Table of contents :

• electromagnetic radiations (EMR).
• light amplification by stimulated emission of radiation (LASER) : a device which transforms light of various frequencies into an extremely intense, small, and nearly nondivergent beam of monochromatic radiation in the visible region with all the waves in phase. Capable of mobilizing immense heat and power when focused at close range, it is used as a tool in surgical procedures, in diagnosis, and in physiologic studies. With proper equipment, any EMR can made to operate like a LASER :
• microwave amplification by Stimulated Emission of Radiation (MASER)
Web resources : Laser Fundamentals
Pathogenesis : chemists already knew that magnetic fields can affect certain chemical reactions involving radicals, molecules that contain unpaired electrons. But these reactions rely on molecules not found in living creatures. The question remained whether such magnetic-field effects occur in real biological systems. A mutant strain of the bacterium Rhodobacter sphaeroides called R-26 lacking a protective chemical known as a carotenoid that normally soaks up damaging radicals:
• nonionizing radiations (NIR) (n < 3,000 THz ; E < 10 eV)
• radiofrequencies (RF) is the name given to that section of the electromagnetic spectrum from frequencies of 300 kHz to 300 GHz => radiofrequency electromagnetic fields (RFEMF). Frequencies in the THz range (THz = 1012 Hz) are difficult to measure directly (they can be measured by heterodyning: observing the difference frequencies they make with reference signals).

Classification systems :
• divided into bands whose wavelengths and frequencies begin and end on metres times a power of 10. Because the speed of light is close to 3 ^.10⁸ m/s, when these bands are expressed in frequencies, their limits are 3 times a power of 10 Hz
• bands allotted for specific types of communication.
Subdivision :
• radiowaves
• super low and extra low frequency (ELF) => extremely low frequency electromagnetic fields (ELF-MF / ELF-EMF) (0 Hz < n < 300 Hz)

Sources : electricity authorities power lines (50 < n < 60 Hz)
Biological effects :
• cell damage
• considerable long-term exposure to 50-Hz EM fields among nonsmoking power linesmen is associated with a slight increase in lymphocytes with chromatid-type breaks, expecially among those power linesmen who had worked earlier in their life^ref
• synergism
• cells exposed to both ionizing radiation and 60 Hz magnetic fields demonstrated an enhanced frequency of near tetraploid chromosome complements, a feature not observed following exposure to only ionizing radiation^ref
• cancers :
• residential magnetic field exposures commonly experienced by US women do not influence risk of breast cancer^ref
• childhood leukemia
• risk of acute lymphoblastic leukemia (ALL) in children 0-9 years of age whose mothers were exposed to the highest occupational levels of ELF-MF during pregnancy^ref. Studies with aneuploid cell lines raised the hypothesis that ELF EMF may act as a coleukaemogen by compromising DNA damage response to genotoxic agents such as ionising radiation^ref.
• various studies observed an increased risk for tumours in the hematopoietic and lymphatic tissue of people living in the proximity of TV and radio broadcast transmitters. However, methodological limitations to these studies have been identified and their findings are controversial.
• exposure of human peripheral blood mononuclear cells to extremely low frequency pulsed electromagnetic fields (PEMFs) increased both the spontaneous and the PHA- and TPA-induced production of IL-1 and IL-6^ref.
• childhood exposure to residential contact currents may play a role in explaining any possible association between residential magnetic fields and childhood leukemia
• CNS alterations :
• significant 5-HT increase at birth, 15 and 21 days, in the cerebral cortex of growing rats exposed during pregnancy^ref
• increased risk of
• Alzheimer's disease (AD) (RR up to 4 among welders and other workers occupationally exposed to ELF-MF^ref; long-term exposure >=0.2 mT in lifetime principal job leads to a multivariate-adjusted relative risks of 2.3 for AD and 2.0 for dementia. Similar patterns were not seen in women, which may in part be the result of a greater exposure misclassification in women than in men. A similar sex-specific pattern was seen for the associations with average ELF-MF exposure throughout the work life. A dose-response relation was suggested in men, with multivariate-adjusted relative risks of 2.4 for AD and 2.5 for dementia for the upper tertile of lifetime average exposure^ref)
• amyotrophic lateral sclerosis (ALS) (RR up to 2.2 among welders and other workers occupationally exposed to ELF-MF.
• teratogenicity :
• IVF-derived mouse embryos are more sensitive than NB-generated embryos to ELF-MF, and that this sensitivity occurs earlier in development^ref
• the human auditory response to pulses of radiofrequency (RF) energy, commonly called RF hearing, is a well established phenomenon. RF induced sounds can be characterized as low intensity sounds because, in general, a quiet environment is required for the auditory response. The sound is similar to other common sounds such as a click, buzz, hiss, knock, or chirp. Effective radiofrequencies range from 2.4 to 10 000 MHz, but an individual's ability to hear RF induced sounds is dependent upon high frequency acoustic hearing in the kHz range above about 5 kHz. The site of conversion of RF energy to acoustic energy is within or peripheral to the cochlea, and once the cochlea is stimulated, the detection of RF induced sounds in humans and RF induced auditory responses in animals is similar to acoustic sound detection. The fundamental frequency of RF induced sounds is independent of the frequency of the radiowaves but dependent upon head dimensions. The auditory response has been shown to be dependent upon the energy in a single pulse and not on average power density. The weight of evidence of the results of human, animal, and modeling studies supports the thermoelastic expansion theory as the explanation for the RF hearing phenomenon. RF induced sounds involve the perception via bone conduction of thermally generated sound transients, that is, audible sounds are produced by rapid thermal expansion resulting from a calculated temperature rise of only 5 x 10^-6 °C in tissue at the threshold level due to absorption of the energy in the RF pulse. The hearing of RF induced sounds at exposure levels many orders of magnitude greater than the hearing threshold is considered to be a biological effect without an accompanying health effect. This conclusion is supported by a comparison of pressure induced in the body by RF pulses to pressure associated with hazardous acoustic energy and clinical ultrasound procedures.
• ultra low frequency (ULF) (300 Hz < n < 3 kHz) : electromagnetic waves in this range are not strongly absorbed by water or the earth. They may therefore be used to communicate with submarines and with mines. The wavelengths are so long that antennae may be huge. One disadvantage is that, with such low frequency, one can only modulate their amplitude or frequency very slowly (eg with morse code) so they cannot carry much information. This is not a disadvantage if only the phase is required, as is the case for

Sources : navigation systems
• very low frequency (VLF) (3 < n < 30 kHz; l > 10 km) : again, the information carrying capacity is limited.

Sources : navigation systems.
• low frequency (LF) (30 < n < 300 kHz; 1 < l < 10 km) : this band has the advantage that it can propagate around the Earth, by refraction and reflection at the ionisphere or the surface of the Earth itself. Indeed, these 2 conductors form a waveguide for waves in this range, which can therefore be used to communicate across the oceans and around the world.

Sources : radioamateur stations
• medium frequency (MF) (300 kHz < n < 3 MHz; 0.1 < l < 1 km) : these waves are not so well reflected/refracted by the ionosphere, but at night there is enough reflection that one can pick up radio stations hundreds or thousands of km away

Sources : Amplitude Modulated (AM) radio band (535 kHz - 1.605 MHz (200 < l < 600 m)). The frequencies 30-535 kHz are used for maritime communication and navigation and for aircraft navigation. Carrier frequencies of 540 to 1600 kHz are assigned at 10 kHz intervals. You do not need an antenna that has a comparable length, although the strength of the signal will increase as you increase the antenna length.
• high frequency (HF) (3 < n < 30 MHz; 10 < l < 100 m) : as the frequency of the carrier wave increases, it becomes possible to encode more information and to crowd channels (proportionately) closer together.

Sources :
• short waves : 1.605 < n < 54 MHz (5.55 < l < 187 m)
• 1,605 kHz - 30 MHz : amateur radio, government radio, international shortwave broadcast, fixed and mobile communications.
• 30-50 MHz  : government and non-government, fixed and mobile. Includes police, fire, forestry, highway, and railroad services.
• 50-54 MHz : amateur
• citizens band (CB) radio : several bands around 27 MHz.
• channels used for radio control
• very high frequency (VHF) (30 < n < 300 MHz; 1 < l < 10 m) : you need an unobstructed path to the transmitter that is not much different from a straight line. Antennae are often made to be about one quarter or one half wavelength long.

Sources :
• frequency modulation (FM) radio (88 - 108 MHz) : the wavelength are about 3 metres, so simple antennae should be about 1/4 or 1/2 this length.
• television (several different bands between 54 and 220 MHz) : television carries more information than radio does--pictures plus sound-- and so needs broader bands for each channel
The carrier frequencies for VHF television Channels 2-4 cover the frequency range 54 to 72 MHz. There is a band from 72-76 MHz which is reserved for government and non-government services, including a standard aeronautical beacon at 75 MHz. VHF TV channels 5 and 6 are between 76 and 88 MHz. The FM radio band is from 88 to 108 MHz between VHF television Channels 6 and 7.Above the FM is a range 108-122 MHz for aeronautical navigation including localizers, radio ranging and airport control. From 122 to 174 MHz is another general service band for both government and non-government signals. It includes fixed and mobile units and amateur broadcast. Channels 7 through 13 span the frequency range 174-216 MHz. 216-470 MHz includes a number of fixed and mobile communication modes, including some aeronautical navigation and citizens radio. 470-890 MHz includes UHF television channels 14 to 83. Frequencies 890-3000 MHz include a variety of aeronautical and amateur uses, studio-transmitter relays, etc. There are radar bands 1,300-1,600 MHz. The FM stations are assigned center frequencies at 200 kHz separation starting at 88.1 MHz, for a maximum of 100 stations. These FM stations have a 75 kHz maximum deviation from the center frequency, which leaves 25 kHz upper and lower "gaurd bands" to minimize interaction with the adjacent frequency band. Television channels have 5 MHz separation.
Biological effects : the weight of evidence available indicates that, for a variety of frequencies and modulations with both short and long exposure times, at exposure levels that do not (or in some instances do) heat the biological sample such that there is a measurable increase in temperature, RF exposure does not induce DNA strand breaks,  chromosome aberrations, sister chromatid exchanges (SCEs), DNA repair synthesis, phenotypic mutation, or transformation. While there is limited experimental evidence that RF exposure induces micronuclei formation, there is abundant evidence that it does not. There is some evidence that RF exposure does not induce DNA excision repair, suggesting the absence of base damage. There is also evidence that RF exposure does not inhibit excision repair after the induction of thymine dimers by UV exposure, as well as evidence that indicates that RF is not a co-carcinogen or a tumor promoter. Teratologic effects can occur only from exposure levels that cause biologically detrimental increases in body temperature.
Medical applications : radiofrequency ablation (RFA)
• microwaves (MW) => high frequency electromagnetic fields (HF-EMF) (300 MHz < n <  300 GHz ; 1 mm < l < 1 m. Some consider microwaves those with 800 MHz < n < 300 GHz and 37.5 cm < l < 1 m. The term "microwaves" can be misleading as the shortest wavelength is 1 millimeter not 1 "micro" meter)
• ultra high frequency (UHF) (300 MHz < n < 3 GHz; 10 < l < 100 cm)

Sources :
• radio and television broadcast antennas :
• satellite communications (L-band : 390-1550 MHz)
• global positioning system (GPS) : 1.2 -1.6 GHz
• cellular or mobile phones (CP) : MW are made by a transmitter chip and an antenna
• analogue cellular technologies
• C-450, C-Netz , and Nordic Mobile Telephones/450 (NMT450) : 450 MHz
• advanced mobile phone system (AMPS) and narrowband AMPS (N-AMPS) : 800 MHz
• Nordic Mobile Telephones/900 (NMT900), NMT France (NMT-F) and total access communications system (TACS) / Japan access communication system (JTAC) : 900 MHz
• digital cellular technologies
• UltraPhone 110 : 350-500 MHz
• digital AMPS (D-AMPS) : 824-849 and 869-894 MHz
• wireless application protocol (WAP)
• internet protocol (IP)
• IS-54, IS-95 : 800 MHz
• global system for mobile (GSM : the original acronym standed for Groupe Spécial Mobile) communication phones (900 MHz)
• GSM corldless telephone system (CTS). In the home environment, GSM-CTS phones communicate with a CTS Home Base Station (HBS), which offers perfect indoor radio coverage. The CTS-HBS hooks up to the fixed network and offers the best of the fixed and mobile worldsTelecentre-H : 350-500 MHz and 800-1000 MHz.
To test - via Transcranial Magnetic Stimulation (TMS) - the excitability of each brain hemisphere after real or sham exposure to the electromagnetic field (EMF) generated by a mobile phone operating in the Global System for Mobile Communication (GSM), 15 male volunteers attended 2 experimental sessions, 1 week apart, in a cross-over, double-blind paradigm. In one session the signal was turned ON (EMF-on, real exposure), in the other it was turned OFF (EMF-off, sham exposure), for 45 minutes. Motor Evoked Potentials (MEPs) were recorded using a paired-pulse paradigm (testing intracortical excitability with 1 to 17 ms interstimulus intervals), both before and at different times after exposure to the EMF. Short Intracortical Inhibition (SICI) and Facilitation (ICF) curves were evaluated both on the exposed and non-exposed hemispheres. Tympanic temperature was collected during each session. The intracortical excitability curve becomes significantly modified during real exposure, with SICI being reduced and ICF enhanced in the acutely exposed brain hemisphere as compared to the contralateral, non-exposed hemisphere or to sham exposure. Tympanic temperature showed no significant main effect or interactions^ref
• personal digital cellular (PDC) : 800 and 1500 MHz
• iDEN® (Integrated Digital Enhanced Network) : 800 MHz, 900 Mhz and 1.5 GHz bands
• digital cordless standard (DCS) / GSM1800 / E-Netz (1800 MHz)
• JS-008 : CDMA based standard for 1,900 MHz.
• universal mobile telecommunication system (UMTS) : 2 GHz
• Zigbee UWB Standard : 2.4 GHz
Biological effects :
• 900 MHz
• CNS alterations :
• a 'Phantom Scalp' was constructed from a conducting foam mat to form a layer under a 62-electrode EEG cap closely approximating the electrical properties of a human scalp. The mat was placed over a polystyrene manikin head to preserve a correct anatomical arrangement. Electrical signals were recorded with a GSM communications mobile phone handset in place against the side of the 'head'. Amplitude spectra were compared for 3 phone conditions: 'off', 'standby' and 'transmit'. At 217 Hz, significant differences were obtained between 'transmit' and the other 2 conditions, but no significant differences were noted for the physiologically important range 0.5-30 Hz. An anomalous difference was noted for one electrode in the range 30-45 Hz^ref
• traditional EEG was full of noises during operation of a cellular phone. Using a 16-channel telemetric electroencephalograph (Expert^TM) in awake subjects, all the noise was eliminated, and EEG showed interesting changes: after a period of 10-15 s there was no visible change, the spectrum median frequency increased in areas close to antenna; after 20-40 s, a slow-wave activity (2.5-6.0 Hz) appeared in the contralateral frontal and temporal areas. These slow waves lasting for about one second repeated every 15-20 s at the same recording electrodes. After turning off the mobile phone, slow-wave activity progressively disappeared; local changes such as increased median frequency decreased and disappeared after 15-20 min. We observed similar changes in children, but the slow-waves with higher amplitude appeared earlier in children (10-20 s) than adults, and their frequency was lower (1.0-2.5 Hz) with longer duration and shorter intervals^ref
• 30 min mobile phone use has no short-term adverse effects on the human auditory system as assessed with auditory brainstem response (ABR), the ABR recovery function and middle latency response (MLR)^ref
• attention functions may be differentially enhanced after exposing to the electromagnetic field emitted by mobile phones. Furthermore, this transient facilitation effect might be dose dependent^ref
• human peripheral blood lymphocytes (PBLs)
• no statistically significant differences were detected in terms of either human PBLs micronucleus frequency (evaluated by applying the cytokinesis-block micronucleus assay) or cell cycle kinetics in continuous-wave (CW) intermittent exposure (SAR = 1.6 W/kg) for 6 min followed by a 3-h pause (14 on/off cycles) or Global System of Mobile Communication (GSM) modulated signal, intermittent exposure as described above or GSM signal, intermittent exposure as described above 24 h before stimulation with PHA (8 on/off cycles) or GSM signal, intermittent exposure (SAR = 0.2 W/kg) 1 h per day for 3 days^{ref (8/2003)}
• a linear increase in chromosome 17 aneuploidy was observed as a function of the SAR value after in vitro exposure of human PBLs to continuous 830 MHz electromagnetic fields, demonstrating that this radiation has a genotoxic effect. The SAR dependent aneuploidy was accompanied by an abnormal mode of replication of the chromosome 17 region engaged in segregation (repetitive DNA arrays associated with the centromere), suggesting that epigenetic alterations are involved in the SAR dependent genetic toxicity. Control experiments (i.e., without any RF radiation) carried out in the temperature range of 34.5-38.5 degrees C showed that elevated temperature is not associated with either the genetic or epigenetic alterations observed following RF radiation-the increased levels of aneuploidy and the modification in replication of the centromeric DNA arrays. These findings indicate that the genotoxic effect of the electromagnetic radiation is elicited via a non-thermal pathway^{ref (2/2003), comment1, comment2}.
• tumors
• REFLEX study, a 4-year project performed by 12 research groups in 7 European countries and led by Franz Adlkofer of Verum Foundation, a research organization based in Munich, Germany found that levels of radiation equivalent to those from a phone prompted breaks in individual strands of DNA in a variety of human cells, types of damage have been linked with cancer. The level of injury increased with the intensity of radiation and the length of exposure. Hints, but not conclusive evidence, were found for other cell changes, including damage to chromosomes, alterations in the activity of certain genes and a boosted rate of cell division. The damaging effects occurred when cells were exposed to EMR of intensities 0.3-2 W/kg, overlapping with the level of radiation typically emitted by phones of around 0.2-1 W/kg. Other research groups might have missed equivalent harm in their studies because they exposed cells to radiation for too short a time or used laboratory cell types that are resistant to damage. There is a need for more extensive studies to test whether mobile phone radiation damages DNA in people, and whether this is linked to disease. Until then, users should keep their time on the phone to a minimum and use headsets if they are concerned about the risks.
• chronic exposure to 835.62 MHz FDMA or 847.74 MHz CDMA RF radiation had no significant effect on the incidence of spontaneous tumors in F344 rats^ref
• incidence rates for malignancies arising in the head and neck, including those sites that hypothetically receive the highest levels of radio frequency radiation during cellular telephone use, have not changed materially since the introduction of cellular telephones to New Zealand in 1987 to 2003^ref. In studies of a possible association between brain tumours and mobile phone use, the average period mobile phones use was short compared to the known latency period of brain tumours. Although these studies did not establish an overall increased risk of brain tumours associated with mobile phone use, there were some indications of an association. Immediate effects associated with mobile phone use have been observed in human experimental studies that cannot be explained by conventional thermal mechanisms. In total use of analogue cellular telephones gives an increased risk for brain tumours with OR=1.3, whereas digital and cordless phones do not overall increase the risk significantly. Ipsilateral use of analogue phones gives OR=1.7, digital phones OR=1.3 and cordless phones OR=1.2. The risk for ipsilateral use is significantly increased for astrocytoma for all studied phone types, analogue phones OR=1.8, digital phones OR=1.8, cordless phones OR=1.8. Use of a telephone on the opposite side of the brain is not associated with a significantly increased risk for brain tumours. Regarding anatomical area of the tumour and exposure to microwaves, the risk is increased for tumours located in the temporal area on the same side of the brain that is used during phone calls, significantly so for analogue cellular telephones OR=2.3. For acoustic neurinoma OR=4.4 is calculated among analogue cellular telephone users. When duration of use is analysed as a continuous variable in the total material, the risk increased per year for analogue phones with OR=1.04. For astrocytoma and ipsilateral use the trend was for analogue phones OR=1.10, digital phones OR=1.11, and cordless phones OR=1.09. There was a tendency of a shorter tumour induction period for ipsilateral exposure to microwaves than for contralateral, which may indicate a tumour promotor effect^ref. An increased odds ratio of 3.45, 95% confidence interval (CI) 1.77-6.76, was found for vestibular schwannoma (VS) associated with the use of analogue cell phones. During the time period 1960-1998, the age-standardized incidence of VS in Sweden significantly increased yearly by +2.53%. A significant increase in the incidence of VS was only found for the latter of the two time periods 1960-1979 and 1980-1998. For all other brain tumors taken together, the incidence significantly increased yearly by +0.80% for the time period 1960-1998, although the increase was only significant for benign tumors other than VS during 1960-1979^ref. In Denmark (106 acoustic neuroma patients and 212 healthy controls) the overall estimated relative risk of acoustic neuroma was 0.90. Use of a cell phone for > 10 years did not increase acoustic neuroma risk over that of short-term users. Furthermore, tumors did not occur more frequently on the side of the head on which the telephone was typically used, and the size of the tumor did not correlate with the pattern of cell phone use. The results of this prospective, population-based, nationwide study, which included a large number of long-term users of cellular telephones, do not support an association between cell phone use and risk of acoustic neuroma^ref. Even in Sweden (148 patients and 600 controls) the overall OR for VS associated with regular mobile phone use is 1.0, but 10 years after the start of mobile phone use the estimates relative risk increases to 1.9; when restricting to tumors on the same side of the head as the phone is normally used, the relative risk is 3.9^ref.
• use of a mobile phone, either in the short or medium term, was not associated with an increased risk of glioma among 966 people aged 18 to 69 years diagnosed with a glioma from 1 December 2000 to 29 February 2004. This is consistent with most but not all published studies. The complementary positive and negative risks associated with ipsilateral and contralateral use of the phone in relation to the side of the tumour might be due to recall bias. The overall odds ratio for regular phone use was 0.94 (CI₉₅ = 0.78 to 1.13). There was no relation for risk of glioma and time since first use, lifetime years of use, and cumulative number of calls and hours of use. A significant excess risk for reported phone use ipsilateral to the tumour (1.24, 1.02 to 1.52) was paralleled by a significant reduction in risk (0.75, 0.61 to 0.93) for contralateral use^ref
• cutaneous blood flow is modified by non-ionizing electromagnetic radiations, emitted by a cellular phone^ref :
• without CP contact with the skin
• CP turned off but in contact with the ear skin : + 61.38%
• CP contact and turned on : + 131.74%
• CP contact, turned on and receiving : + 157.67%
• CP contact and set turned on : + 139.21%
• CP contact and turned off : + 122.90%;
• without CP contact : 57.58+/-10 PU
In such exposures, the electromagnetic energy may reach very high values of power density in peak at relatively low time-averaged levels of power density.
Web resources :
• Independent Expert Group on Mobile Phones (IEGMP)
• Stewart Report : "Mobile Phones and Health" : children could be more at risk from the radiowaves emitted by mobile phones because their brains are still developing and their skulls are thinner, making it easier for the radiowaves to penetrate them.
• Mobile Operators Association (MOA), formerly known as the Mobile Telecoms Advisory Group (MTAG) within the Federation of the Electronics Industry (FEI)
• National Radiological Protection Board (NRPB)
• Advisory Group on Non-Ionising Radiation (AGNIR)
• Advisory Group Report
• INTERPHONE Study, coordinated by the WHO's International Agency for Research on Cancer (IARC) in Lyon, France, was set up in 1998 to investigate whether exposure to the radio-frequency electromagnetic fields from mobile phones causes damaging health effects. It involves 13 countries (Australia, Canada, Denmark, Finland, France, Germany, Israel, Italy, Japan, New Zealand, Norway, Sweden and the UK). In order to maximise the power of finding a risk if it exists, the studies are mainly focused on tumours in relatively young people (30-59 – who had the highest prevalence of mobile phone use 5 to 10 years ago) and on regions within the participating countries with longest and highest use of mobile phones. It is expected that the studies will include about 6000 cases of gliomas and meningiomas (both benign and malignant), 1000 cases of acoustic neurinoma, 600 cases of parotid gland tumours and their respective controls. Studies are now complete in nearly all the countries involved in the INTERPHONE project, and the final results are expected to be released in early 2005, according to Elisabeth Cardis, chief of the radiation and cancer unit at the IARC. 5 of the countries involved in the project are also planning to start prospective studies following 250,000 people (50,000 in each country) to confirm any effects that INTERPHONE finds.
• super high frequency (SHF) (3 < n < 30 GHz; 1 < l < 10 cm)

Sources :
• communication with satellites
• civilian, police and military RAdio Detecting And Ranging (RADAR) used on aircraft, ships and weather forcasters : 1,300 to 1,600 MHz. An electronic instrument using UHF radio waves to detect distant objects and measure their range by how they scatter or reflect radio energy. Precipitation and clouds are detected by measuring the strength of the electromagnetic signal reflected back. Examples are doppler radar (weather radar that measures direction and speed of a moving object, such as drops of precipitation, by determining whether atmospheric motion is horizontally toward or away from the radar. Using the Doppler effect, it measures the velocity of particles) and next generation weather radar (NEXRAD) (a network of advanced Doppler radars implemented in the United States between 1992 and 1996, it detects the location and intensity of precipitation out to a range of 143 miles from the radar site. NEXRAD Doppler radar is highly sensitive and can detect precipitation from very light rain and snow up to the strongest thunderstorms with accuracy and detail. Sometimes, however, the radar's extreme sensitivity will cause ground clutter and other non-precipitation echoes to be displayed in the vicinity of the radar site)
• long distance trunk telephone communications
• TErrestrial Trunked RAdio (TETRA)
• microwave ovens : 2.45 GHz (MW are made by a magnetron)
• extra high frequency (EHF) (30 < n < 300 GHz; l < 1 cm)

Sources :
• cosmic microwave background radiation (CMR) is the leftover heat emitted 400,000 years after the big bang. It permeates the entire universe at a temperature of 2.725 +/- 0.001°K. Close examination of slight CMR intensity variations in different parts of the sky help cosmologists study the formation of galaxies. The intensity is measured in Mega Jansky per steradian
• not much used for radio communication, because of the technological difficulty of encoding and decoding amplitude and frequency modulation at such high frequencies.
Other sources : pulsed electromagnetic fields (PEMFs)
• a variety of industrial inductive and dielectric heating devices
• traffic speed cameras
• medical devices such as MRI and diathermy devices
• stars
Medical applications : microwave coagulation therapy (MCT)
Biological effects :
• non-thermal effect
• no evidence of a co-promoting effect of exposure to GSM-900 signals using the 7,12-dimethylbenz(a)anthracene (DMBA) female Sprague-Dawley rat model^ref
• thermal effect : they are absorbed by the lens causing acquired cataract
Web resources : Neurological effects of radiofrequency electromagnetic radiation
• infra-red (IR) radiations (0.3 < n < 385 THz; 760 nm < l < 1 mm)
• near-IR (NIR) : 0.76 - 5 mm

Applications : metal nanoshells
• mid-IR (MIR) / intermediate IR (IIR) : 5-30 mm
• far-IR (FIR) : 30-1000 mm
Sources :
• fire
• living organisms
• remote control signals can be detected by most camcorders
• night vision scopes/goggies use a special camera that senses IR ands converts the image to visible light. Some IR cameras employ an IR lamp to help illuminate the view.
• IR LASERs are used for burining objects (ex. product best-before date-codes)
Detection : heat receptors (some snakes have IR sensors)
Biological effects : they are absorbed by the lens causing acquired cataract
• visible light (385 < n < 750 THz; 400 < l < 760 nm)

Sources : Sun optic window 290-1400 nm
Laboratory examinations : luximeter (luminance)
Biological effects :
• vision
• photosynthesis
• retinal burns
• computer vision syndrome (CVS)
• asthenopia, headache
• retinal degeneration from chronic exposure to blue light
The diodes used in solar cells work at a potential difference of about 0.6 V, so every visible photon has enough energy to shift one electron across the interface
• ultra-violet (UV) radiations (750 < n < 3,000 THz; 200 < l < 400 nm) : beyond the violet end of the spectrum; said of electromagnetic rays or radiation between the violet rays and the x-rays. These rays have powerful actinic and chemical properties. Physicists have divided UV light into :
• near UV (NUV) : 300-400 nm (near the visible spectrum)
• medium UV (MUV) : 200-300 nm
• vacuum UV (VUV) / far UV (FUV) : 100-200 nm
• extreme UV (EUV / XUV) : 10-100 nm
In the 1930's the Commission Internationale de l'Eclaraige (CIE : International Commission on Illumination) introduced for photobiological spectral bands :
• ultraviolet A (UVA) (320 < l < 400 nm), comprising > 99% of UV reaching the surface of the earth. UVA enhances the harmful effects of UVB radiation and is also responsible for some photosensitivity reactions; it is used therapeutically in the treatment of a variety of skin disorders.
• UVA-1 (340 < l < 400 nm)

Biological effects : they are absorbed by the derm and vitreous humor
• UVA1/2 for DNA altering effects at 340 nm.
• UVA-2 (320 < l < 340 nm)

Biological effects : they are absorbed by the derm and vitreous humor, and can inactivate previtamin D₃
• ultraviolet B (UVB) (290 < l < 320 nm : the CIE originally divided UVA/B at 315 nm, later some photo-dermatologists divided it at 320 nm), comprising < 1% of the UV radiation reaching the earth's surface

Sources : those produced by the Sun are partially filtered by ozonosphere
Biological effects : they are absorbed by
• basal layers of the epidermis
• convert provitamin D₃ in previtamin D₃
• acute exposures leads tosunburn
• chronic exposure leads to
• atrophic/dystrophic dermatitis
• damaging photochemical changes within cells, including damage to DNA, leading to premature aging of the skin, premalignant and malignant changes, and a variety of photosensitivity reactions
They induce a transient appearance of neutrophils in papillary derm already 5 hrs after irradiation, reaching a peak at 24 hrs : this causes a T_h2 shift thanks to IL-4.
• minimal erythemogenic dose (MED) is the quantity of radiant energy required to produce a E+/- erythema 24 hours after exposure. A template with holes (approximately 1 x1 cm) is placed on a sun-protected area (hip or buttock) which is then irradiated with different doses of UV-B at a fixed distance. If broadband UVB are used, the following escalating doses are recommended : 20, 40, 60, 80, 100, and 120 mJ/cm²; if narrowband UVB are used : 200, 400, 600, 800, 1000, and 1200 mJ/cm²
The erythema action spectrum is believed to parallel the one for carcinogenesis. UV-induced DNA damage gives rise to mutations and skin cancer.
Prevention :
• sunscreens and other skincare products already contain a range of products - such as antioxidants from green tea - which are thought to prevent DNA damage. But because these are marketed as cosmetics, they have not been as rigorously tested as drugs. They passively block damaging UV rays but are sometimes ineffective because users often do not apply them frequently enough or in sufficient quantities
• dioxybenzone : an ultraviolet sunscreen applied topically to the skin
• bacterial DNA repair enzyme T4 endonuclease V in a liposomal delivery vehicle applied topically (T4N5 liposome lotion) lowers the rate of new actinic keratoses and basal-cell carcinoma in patients with xeroderma pigmentosum^ref
• treatment of skin cells in vitro with thymidine dinucleotide (pTT) activates p53^ref and increases the ability of cells to repair subsequent UV-induced DNA damage by enhancing endogenous DNA repair capacity^ref. Topical pTT pretreatment enhances the rate of DNA photoproduct removal, decreases UV-induced mutations, and reduces photocarcinogenesis in UV-irradiated hairless WT repair-proficient and Xpc^+/- heterozygous partially repair-deficient mice, both transgenic for the lacZ/pUR288 mutation-indicator gene : treated animals stayed free of pre-cancerous skin lesions for 16 weeks, while unprotected ones succumbed after 9 weeks. These data support the existence of inducible mammalian DNA damage responses that increase DNA repair capacity after DNA damage and hence reduce the impact of future exposures to environmental carcinogens. The ability of topically applied pTT to induce protective physiologic responses that normally result from DNA damage suggests a previously undescribed means of reducing skin cancer in high-risk individuals : the fragments could be a powerful new ingredient in sunscreens - one whose effect lasts days rather than hours^ref
• cornea
• vitreous humor
Applications : treatment of skin disorders.
• ultraviolet C (UVC) (200 < l < 290 nm)

Sources :
• Sun => they are totally filtered by ozonosphere
• artificial source
Biological effects : absorbed by cornea and epidermis
Applications :
• used for germicidal purposes
• ultraviolet phototherapy
Sources :
• Sun
• objects hotter than the sun (eg some massive young stars)
Biological effects : a UV photon has enough energy to damage DNA molecules in your cells
Bumble-bees can see light in the UVA range and so flowers have UV colours to attract them (bees can also see the polarisation of light, which they use to navigate)
Laboratory examinations :
• field analyzers (e.g. TE307 Acritalia or 15 ID Alenia) (from ELF to UHF)
• magnetic field (H) [A/m or tesla (T)]
• electric field (E) [V/m]
• power density (S) = E x H [W/m²] (from SHF to EHF)
• spectrum analyzer (e.g. Hewlett Packard)
• specific absorption rate (SAR) [W/kg] (from VHF to EHF)
• biological effects of ionizing radiation (BEIR)
Electromagnetic interference (EMI) : despite the introduction of modern pacemakers (PM) and bipolar lead systems, EMI still remains to be a concern during daily lives when patients are exposed to cellular phones, electronic security systems, and several household appliances : anyway there is no EMI risk of an induction oven in patients with bipolar or right-sided unipolar pacemakers^ref
Web resources :
• The International EMF Project at WHO
• International Commission on Non-Ionizing Radiation Protection (ICNIRP)
• actinic or ionizing radiations (IR) : pertaining to those rays of light beyond the violet end of the spectrum (E > 12.4 eV; n > 3,000 THz) that produce chemical effects, as in photography or heliotherapy (actinism / actinicity)
• X rays or Röntgen rays (10 pm < l < 200 nm; 3 ^. 10⁸ < n < 3^.10⁹; 12.4-124 keV)
• 'soft' X rays with longer wavelengths and lower energies are stopped by (enough) air
• 'hard' X rays with shorter wavelengths and higher energies can penetrate deeply into tissue
Sources :
• natural
• some radioactive sources
• very hot objects like neutron stars
• artificial
• kV : conventional roentgentherapy. X-ray machine : smashing DV-accelerated (high energy) electrons into heavy metal targets. X-ray emission apparatuses include
• vacuum tube : a glass tube from which the air has been exhausted to a high degree of vacuum.
• x-ray tube : a glass vacuum bulb containing a diode with DV = 40-150 kV : the cathode (₇₄W) expell electrons by thermoelectric effect (DV = 10 V) towards a rotating anodic disc : catodic electrons interacts with both anodic electrons (one inner anodic electron is excited and replaced by an outer electron, generating heat for 99% and characteristic X-rays for 1%) and anodic nuclei (₇₄W) generating a continuum spectrum of braking radiations). The mA current modifies the width of the focal spot. By increasing
• catodic DV => increased electron expulsion => increased X-ray flow
• catodic-anticatodic DV => increased electron energy => increased X-ray energy => hard X-rays

• Chaoul tube : a low voltage x-ray tube so designed as to permit the anode to be located at 2 cm. from the body, thus permitting intense but very superficial tissue penetration of the ionizing radiation beam.
• Coolidge tube : a vacuum tube for the generation of x-rays in which the cathode consists of a spiral filament of incandescent tungsten and the anode (the target) of massive tungsten.
• Olshevsky tube : an x-ray tube constructed to use only the stronger rays which pass through the target and armoring the rest of the tube.
• exit window
• filter which eliminates low-energy (ie high-wavelenght) characteristic X-rays
• collimator
X photons interact with patient's atoms in 3 ways :
• classical or coherent diffusion => photon diffusion
• photoelectric effect
• Compton effect (conventional X-rays)
• MV :
• linear accelerator (LINAC)  : machine generating ionizing radiation from electricity; these machines are commissioned to treat with x-rays (E = 4-20 MeV) or electrons; depth of treatment varies with energy and type of radiation
• betatron : an apparatus for accelerating electrons to millions of electron volts by means of magnetic induction
Biological effects : their energies are enough to ionise atoms and to destroy chemical bonds
Applications : radiotherapy
• extremely high (millimetre waves, MMW) frequency electromagnetic fields
• g rays (l < 10 pm)

Sources :
• byproduct of radioisotope decays (e.g. ⁶⁰Co or ¹³⁷Cs)
Applications : radiotherapy
Symptoms & signs :
Epidemiology : < 4,000 people are likely to die as a result of Chernobyl. That was the conclusion released by the United Nations and the governments of Ukraine, Belarus and Russia in September 2005, in the most comprehensive assessment of the accident so far. But despite promising "definitive" answers the report, based on 2 decades of research, has done little to resolve the debate over Chernobyl's impact. The estimate drew howls of protest from environmental groups, which accused the UN's Chernobyl Forum of a whitewash. And scientists whose work is cited in the report are concerned about how their figures were presented, pointing out that the true cost of the disaster will not be known for decades to come, if ever. Chernobyl's runaway nuclear reaction on April 26, 1986 was triggered by a faulty safety test, and exacerbated by a design flaw that caused a catastrophic temperature rise in the reactor core. This caused about 6.7 tonnes of radioactive material to spread for hundreds of kilometres around the site. 2 of the most significant elements in the chemical cocktail were iodine and caesium, and the most devastating effects were seen within a few tens of km of the reactor, in the region where Ukraine, Belarus and Russia meet. In the confusion that followed, local families continued to graze and milk their cattle on contaminated land. Many predicted that the accident would cause hundreds of thousands of cancers. The forum reports that the fallout has since caused about 4,000 cases of thyroid cancer, mainly in children and adolescents. But just 15 of these patients have died. Along with highly exposed rescue workers who brought the reactor inferno under control, 62 deaths have been attributed directly to the accident so far. There has been no significant increase so far in the incidence of other cancers. In total, it said, "up to 4,000 people" may ultimately die as a direct result of the disaster — much lower than previous estimates. The argument stems from uncertainty about the health effects of low doses of radiation. Evidence from survivors of the atomic bombs dropped on Nagasaki and Hiroshima has allowed researchers to predict the effects of high doses. But as the exposure drops, so does the understanding of its impact. In 2005, a working group of the US National Research Council concluded that even tiny amounts of radiation cannot be considered safe. In contrast, the forum based its headline figure on just the 600,000 people exposed to the most radiation, predicting that roughly 4,000 of them will die as a result. The full report acknowledges that, of 6.8 million others living further from the explosion who received a much lower dose, Chernobyl will kill another 5,000 — more than doubling the projected death toll. But this is not mentioned in the report's 50-page summary or the accompanying press release. The figures come from a study published in 1996 by Elisabeth Cardis of the International Agency for Research on Cancer in Lyon, France. The extra 6.8 million people were, on average, exposed to a radiation dose of just 7 mSv — little more than the natural background delivers in a year in most parts of the world. A decision was made to focus on the lower 4,000 figure, partly as a reaction to the inflated estimates of past decades. Some of the higher death tolls come from those who believe that estimates of those potentially affected should extend to everyone in Europe:

In a report commissioned by Green Party members of the European Parliament, radiation scientist Ian Fairlie calculated that of the hundreds of millions of people who could possibly have received any radiation at all from Chernobyl, 30,000–60,000 could die as a result^ref. Cardis is also about to publish a study of the pan-European impact. She concludes that, of 570 million people in Europe at the time, 16,000 will ultimately die as a result of the accident — 0.01% of all cancer deaths. But it will be virtually impossible to assess the ultimate death toll. Cancer causes about a quarter of all deaths in Europe, so weeding out those cases triggered by Chernobyl cannot be done with statistical confidence. Some researchers also take issue with the report's conclusion that there are no hereditary effects in children born after the disaster. The fact that we haven't seen anything doesn't mean there isn't an effect : it's just too early to see an increase. Until Chernobyl survivors' children and grandchildren grow up, the only way to assess such effects is to look for DNA mutations. Increased genetic changes have been found in the children of irradiated parents — but the fingerprinting technique he used only allowed him to look at non-coding DNA^ref. Coding regions are also likely to be affected. DNA chips currently being developed will allow mass screening of samples from thousands of people, he says, and could pick up effects too small to have been spotted so far. The real necessity now is to organize proper blood-sample banks. Many are calling for research to track effects such as cancer or infertility in subsequent generations. But although such monitoring is seen as essential, some worry that wrangling over death tolls and radiation risk is hampering survivors' recovery. Rough estimates of death tolls allow governments to set up policies to manage the future health effects. But the focus on the figure of 4,000 obscured a more important message of the report: that myths about the threat of radiation have created a "paralysing fatalism" among residents of affected areas. Instead Vinton hopes that Chernobyl's legacy can be seen as a social problem. Chernobyl's most serious impact was on the mental health of about 7 million people labelled as victims of the accident. Aid from the governments of Russia, Belarus and Ukraine has created a culture of dependency, it argues, which may have encouraged exaggerated fears of ill-health. Poor diet, lack of exercise and smoking are all linked to such apathy. It is hard to separate the stress of Chernobyl from the effects of collapse of the Soviet Union. But Chernobyl aid has drained resources. In 1991, Belarus spent 22.3% of its budget on aid; today that figure is still 6%. The forum's report recommends that governments reassign the cash towards regenerating the region and developing infrastructure. The hottest spots will be radioactive for centuries. But the most prevalent isotope, caesium-137, has a half-life of about 30 years and scientists estimate that much of the abandoned area will become habitable over coming decades. The 30-km exclusion zone around Chernobyl is likely to remain off limits. But in other evacuated areas roads should be rebuilt, and people encouraged to start farms and businesses. Projects to build hospitals and schools are already helping people to help themselves. Some of the radioactive emissions were carried by the wind to Sweden. Heavy rain caused a relatively large amount, about 5% of the Cesium-137 released in the disaster, fell on Sweden, above all along the coastal area of Northern Sweden and northern central Sweden. The fallout in Sweden was unevenly distributed and, compared with the areas close to the nuclear power station at Chenobyl, considerably less. Anyway a statistically determined correlation between radioactive fallout from the Chernobyl accident and an increase in the number of cases of cancer in the exposed areas in Sweden is reported during the years 1988 through 1996. There is a statistically established correlation between the degree of fallout and an observed rise in the number of cancer cases. The increase involves all types of cancer in the aggregate. On the other hand, no clear effect can be seen for individual forms of cancer, not even for those types that have been regarded as especially susceptible to radiation, such as leukemia or thyroid cancer. It is remarkable that an increase in cancer morbidity could have occurred after such a relatively short time following the accident, but just such a short time period has been described for groups exposed to radioactive radiation. If the correlation found here is not a product of chance, or other unknown disturbances than those corrected for in the analysis, then one possible explanation is that the radiation hastened the growth of already established tumors in their early stages, rather than that new tumors occurred.
Dosimetry^ref : the determination by scientific methods of the amount, rate, and distribution of radiation emitted from a source of ionizing radiation
• physical dosimetry : the determination of the level of exposure to ionizing radiation by means of radiation measuring instruments such as environmental monitoring devices or individual dosimeters.
• counter : a device for enumerating ionizing events
• Geiger-Müller counter : a radiation counter that uses a gas-filled tube to indicate the presence of ionizing particles; the type and energy of a particle cannot be determined because the degree of ionization produced is independent of them. It is highly sensitive to b particles, but relatively insensitive to g and x-rays.
• proportional counter : a gas-filled radiation detection tube in which the pulse produced is proportional to the number of ions formed in the gas by the primary ionizing particle; thus it is possible to discriminate among radiations of different energies or types.
• scintillation counter : an instrument for indicating the emission of ionizing particles, making possible the determination of the concentration of radioactive isotopes in the body or other substance; the radiation is absorbed by a specific type of crystal or liquid that subsequently emits minute flashes of light, which are detected and amplified by a photomultiplier tube and counted if they fall within a preset window of energies characteristic of the radioisotope in question
• scintillation or gamma camera : an electronic instrument that produces photographs or cathode-ray tube images of the gamma ray emissions from organs containing tracer compounds
• Anger camera (the original and most commonly used type) : a device used to form an image of the distribution of a gamma ray–emitting radionuclide in a patient. The radiation is passed through a collimator to reduce scatter and interacts with a sodium iodide crystal, resulting in the production of pulses of light, which are detected and converted to amplified electrical signals by an array of photomultiplier tubes behind the crystal. A pulse height analyzer then discards all but those signals arising from the photopeak of the nuclide being imaged, and the remaining signals are used to form an image of the distribution of the radionuclide on a cathode ray tube. It was the original, and is by far the most commonly used, form of scintillation (or gamma) camera, and the terms are often used interchangeably.
• multicrystal versions
• dosage meter / dosimeter : in radiology, an instrument used to detect and measure exposure to radiation of either personnel or radiotherapy patients
• film badge : a pack of radiographic film or films, usually worn on the body during potential exposure to radiation in order to detect and quantitate the dosage of exposure. A.k.a. thermoluminescence dosimeter : thermoluminescence is the production of light by a substance when its temperature is increased
• source activity : 1 Bq (becquerel) = 1 dis/s = 2.7 x 1011 Ci (curie) / mol . 1 Ci = number of disintegrations/s in 1 g of ²²⁶Ra ===> ²²²Rn + a
• linear energy transfer (LET) : total charge of ions (keV) / mm
• high LET (low penetration and direct, densely ionizing) : particulated radiations, less influenced and poorly sensitive to O₂ sensitization
• low LET (high penetration and indirect, sparsely ionizing) : b^- and EMR, highly sensitive to O₂ sensitization
• doses usually referred to a given time
• exposure dose (total electric charge of produced ions / 1 Kg of air) : 1 C/Kg = 3876 R (röntgen) . 1 R = dose of 250 keV X-rays that in normal conditions (T = 0°C and P = 1 atm) is able to produce 2 x 10⁹ ion pairs in 1 cm³ of air in 1 minute.
• Behnken's unit (R) : a unit of x-ray exposure, being that quantity which, when applied in 1 cc of air at 18°C and 760 mm Hg of pressure, engenders sufficient electric conductivity to equal one electrostatic unit, as measured by the saturation current
• Hampson unit : a unit of x-ray exposure; it is one quarter of the erythema dose.
• Kienböck x-ray unit (X) : a unit of x-ray exposure equal to 0.1 erythema dose
• absorbed dose (absorbed energy / tissue mass) = 1 Gy (gray) = 1 J / kg = 100 rad (radiation absorbed dose). 1 rad = 100 erg/g (about 1 R / g)
• specific absorption rates (SARs) averaged over the whole body (W/Kg)
• equivalent dose (absorbed dose from radiations of every type) : 1 Sv (sievert) = 100 REM (röntgen equivalent in man). 1 REM = 1 rad of radiations of every kind.
• relative biological effectiveness (RBE) : the rate between the absorbed dose of standard radiation (X rays with E = 250 keV) able to produce a given biological effect and the absorbed dose of every radiation that produces the same biological effect. It depends on LET
• ionization chamber : a device for measuring ionizing radiation by the measurement of the ionization of the gas contained in the chamber
• free-air ionization chamber : an ionization chamber in which the ionization in an accurately defined volume of free air is measured
• air-equivalent ionization chamber : in radiology, a chamber in which the materials of the wall and electrodes are such that ionizing radiations produce ionization essentially similar to that in a free-air ionization chamber
• thimble chamber : a small, thin-walled ionization chamber, usually with walls of organic material; used as a dosimeter
• tissue-equivalent ionization chamber : an ionization chamber in which the walls, electrodes, and gas are selected to produce ionization essentially equivalent to that which would occur in the tissue under consideration
• biological dosimetry : the determination of the level of exposure to ionizing radiation by measurement of radiation-induced changes such as cytogenetic abnormalities, lymphopenia, and agranulocytosis; the dose is estimated by comparison of the measurements under consideration to those observed in prior radiation accidents.
Radiobiology is the study of events that occur after ionizing radiation is absorbed by a living organism :
• physical stage : excitation and ionization of atoms or molecules
• thermic effect (if E < 1 eV : i.e. from microwaves up to far IR)
• exciting effect (if 1 eV < E < 10 eV : i.e. from near IR up to UV-C). The excited molecule is less electrophilic and so it may be more easily oxidized, producing redox reactions or free radicals (e.g. through photodynamic effect mediated by photosensitizers cycling (380-410 nm : porphirins; 453 nm: bilirubin; eosin; 340-360 nm: flavin; melanin). UVC are specifically absorbed by the aromatic groups in nucleobases (l₁ = 260 nm) leading to dimer formation between consecutive thymine residues in DNA and by aromatic groups in aromatic amino acids (l₁ = 280 nm)
• ionizing (or radicalizing) effect (if E > 10 eV : i.e. X and g electromagnetic radiations and all particulated radiations)

The ionizing mechanism may be :
• Hallwachs photoelectric effect (if 10 eV < E < 0.1 MeV) : incident photon energy is greater than the binding energy of the electron (depends on E^-3 and Z³) => expulsion of a same-energy photoelectron from inner orbitals; no radiation results
• Compton effect or scattering (if 0.1 < E < 10 MeV) : incident photon causes ejection of a Compton recoil electron from outer orbitals (depends on E^-1); a reduced energy photon is scattered by a given angle. In Homo sapiens it occurs only in bones.
• coherent difusion effect : incident photon s deviated by an atomic electron without loss of energy
• pair-production effect (if E > 1.02 MeV) : the incident photon interacts with the nucleus (given that the rest mass of an electron is 0.511 MeV and E=mc², a photon must have at least 1.022 MeV of energy to produce an electron-positron pair) => a b⁺ and a b^- pair results => they annihilate themselves into 2 180°-opposed annihilation photons (g rays each with E = 0.511 keV)
The atomic ionization may be ...
• direct ionization (rare) by charged particles a, b^-, b⁺ and H⁺ : they produce ion pair
• indirect ionization (common) by uncharged particles (neutrons) and X and g electromagnetic radiations : they produce charged particles
• chemical stage : formation of highly reactive free radicals. The biopolymers ionization may be...
• direct ionization (rare)
• indirect ionization (common) : mediated by H₂O ionization or homolysis, both leading to ^.OH production
Ionized molecules may undergo homolysis after reduction or heterolysis. O₂ has a radiosensitizing effect because peroxyls can only be reduced to hydroperoxyls but never reversed !
• biological stage :
• damage to critical targets :
• nuclear DNA : large-sized, complex molecule with difficult repair. Most repair is believed to occur within 6 hours after a treatment.
• single chromosomal strand breaks (SSB) :
• generally repaired readily
• misrepair may result in chromosomal aberrations
• lethal somatic mutation => delayed mitotic or reproductive cell death
• chromosome damage may cause reproductive failure (death at the time of cell division).
• apoptosis is enhanced by toxic treatments
• germinal mutation : heritable change in genes expressed in later generations
• carcinogenesis (somatic cells) : chromosome aberration that may cause oncogene activation or suppressor
• gene loss
• double chromosomal strand break (DSB) are more difficult to repair and may activate an oncogene or inactivate a tumor suppressor gene.
• mitotic or reproductive cell death
• mutation
• carcinogenesis
• only in indirect ionization : damages to nitrogenated nucleobases
• only in indirect ionization :
• proteins
• phospholipid peroxidation
• induction of STP activating expression of genes mediating tissue response
Effects :
• genetic effects (stochastic) : DNA mutations
• somatic effects
• stochastic : cancers
• nonstochastic (see below)
Radiosensitivity is the innate sensitivity of cells, tissues, or tumors to radiation. Both normal and cancer cells are affected by radiation
• factors that influence radiation sensitivity include the following
• increasing radiosensitivity :
• cells in late G₂ and M phases
• hyperoxia. Reoxygenation occurs as the tumor shrinks during RT and previously hypoxic cells become better oxygenated
• poor differentiation (however associated with higher histological grading)
• rapidly dividing cells (anyway also poorly dividing cell types as small lymphocytes and salivary gland cells may experience an interphase death)
• increasing radioresistance :
• cells in the late S phase
• hypoxia
• high differentiation
• nondividing or slowly dividing cells
• large tumor size (often indicates a poorly oxygenated mass that, thus, is less radiosensitive)
• factors related to radiation-induced injury of normal tissue
• patient-related factors
• age
• in children : growth-related factors (e.g., growth retardation, endocrine changes)
• in adults : limited data available
• hemoglobin level
• low hemoglobin has been found to decrease local control probability in cancers such as squamous cell carcinoma of the head and neck, carcinoma of the cervix, and transitional cell carcinoma of the bladder
• little information is available concerning hemoglobin level related to normal tissue reactions.
• smoking : can enhance some early and late effects
• tumor invasion : may interfere with normal tissue reactions
• infection : may increase normal tissue injury, especially when the immune system is compromised
• intrinsic radiosensitivity
• genetic syndromes : clastogenias are associated with increased sensitivity to RT
• autoimmune diseases (e.g., systemic lupus erythematosus)
Tolerance doses (TD) of various normal organs

organ	severe complications	minimal tolerance dose 5/5 (cGy) = the dose, given to a population of patients under a standard set of treatment conditions, that will result in no more than a 5% rate of severe complications within 5 years after treatment.	maximal tolerance dose 50/5 (cGy) = the dose, given to a population of patients under a standard set of treatment conditions, that will result in a 50% rate of severe complications within 5 years after treatment.	whole or partial organ (field size or length)
bone marrow	pancytopenia, leukemias	250 3,000	450 4,000	whole  segmental
liver	acute and chronic hepatitis	2,500 1,500	4,000 2,000	whole  whole (strip)
stomach	perforation, ulcer, hemorrhage	4,500	5,500	100 cm
intestine	radiation enteritis, radiation colitis, radiation proctitis, ulcer, perforation, hemorrhage	4,500 5,000	5,500 6,500	400 cm  100 cm
encephalon	infarction, necrosis	5,000	6,000	whole
spinal cord	infarction, necrosis (radiation myelopathy and transverse myelitis)	4,500	5,500	10 cm
heart	pancarditis (radiation myocarditis and radiation pericarditis)	4,500 7,000	5,500 8,000	60%  25%
lungs	acute and chronic radiation pneumonitis, lung cancer	3,000 1,500	3,500 2,500	100 cm  whole
kidneys	acute and chronic nephrosclerosis	1,500 2,000	2,000 2,500	whole (strip)  whole
bladder	radiation cystitis
fetus	death	200	400	whole
skin	burn wounds, X-ray dermatitis / radiodermatitis, photodermatitis, photoaging, freckle / ephelis, cutaneous malignant melanoma, cutaneous squamous cell cancer (SCC)
thyroid	papillary thyroid carcinoma (90%)
bone	osteosarcoma

Manifestations of radiation effects occur at different times for different tissues
• acutely responding tissues : damage to epithelial stem cells in rapidly rennovating tissues and flogosis due to necrosis mediators => reversible mucositis and erythema within hours to days
• bone marrow
• ovaries : 2 Gy can wipe out 50% of a woman's oocytes : even women receiving a fraction of a standard dose of abdominal, pelvic or total-body irradiation could be left infertile or have an earlier menopause. In cases where chemotherapy is a good alternative, medics could avoid radiation except as a last resort. For many years these side effects have been largely ignored as doctors focused on the more pressing issue of survival : improved treatments now mean that many women survive once-fatal cancers, so patients' subsequent quality of life is being taken into account. Some women facing cancer treatment are given the opportunity to have their oocytes or ovarian tissue frozen, in the hope of using them in assisted-reproduction techniques later.
• testes
• lymph nodes
• oral mucosa
• salivary glands
• esophagus
• stomach
• small bowel
• colon
• larynx
• arterioles
• capillaries
• skin
• bladder
• vagina
• postirradiation syndrome : a symptom complex caused by massive irradiation, with hemorrhage, anemia, and malnutrition
• acute radiation syndrome : a syndrome caused by exposure to a whole-body dose of over 1 Gy of ionizing radiation. Symptoms, whose severity and time of onset depend on the size of the dose, include erythema, radiation enteritis (nausea and vomiting, diarrhea, gastrointestinal hemorrhage), fatigue, fever, petechiae, bleeding from the mucous membranes, lymphocytopenia, granulocytopenia, and thrombocytopenia, epilation, systemic arterial hypotension, tachycardia, and dehydration; death may occur within hours or weeks of exposure.
• subacutely responding tissues demonstrate effects in weeks to several months after RT and include :
• lungs
• liver
• kidneys
• heart
• CNS :
• encephalon
• somnolence syndrome : a transient condition of drowsiness, lethargy, anorexia, and irritability with electroencephalographic changes, occurring in children after irradiation of the head in the treatment of brain tumors, acute leukemia, or non-Hodgkin's lymphoma.
• spinal cord : transverse myelitis due to endovasculitis
• late-responding tissues : chronic damage to parenchymal tissues due to impaired vascularization and sclerosis => effects months to years after RT and include :
• lymph vessels
• thyroid
• pituitary gland
• breasts
• connective tissues
• bones
• cartilage
• endocrine pancreas
• uterus
• bile ducts
• muscles
IR can cause cancer by :
• DNA mutagenesis
• epigenetic mechanisms => down-regulation of E-cadherin and b-catenin (vital for cell-cell adhesion) and connexin 43 (a component of gap junctions) heritable disruption of epithelial cell interactions^ref
Primary prevention : radioprotectant therapy
• human serum albumin (HSA)
• glycerol
• aminothiols
• N-acetyl cysteine (NAC) isomers
• L-N-acetyl cysteine (LNAC)
• D-N-acetyl cysteine (DNAC)
• cysteamine
• amifostine
• strawberries and blueberries are used in diet of astronauts to protect brain cells from cosmic rays during travels beyond Earth's protective magnetic field
• Ca-channel blockers
• acylmelatonin homologs
• substituted anilines
• curcumin
• liposomal lipid A
• 21-aminosteroid U-74389G
• glutamine (a conditionally essential amino acid)
• vitamin C
• vitamin E (more efficacious when given subcutaneously than when given orally)
• pentobarbital acts as a cerebral radioprotectant
• pilocarpine, a salivary stimulant, has been shown to protect salivary glands from g-radiation-induced damage during the radiotherapy of head and neck tumors
• atropine acts as an intestinal radioprotectant
Web resources :
• US Nuclear Regulatory Commission (NRC)
• National Radiological Protection Board (NRPB)
Doctors across Europe are complaining loudly about new regulations on radiation exposure, which they say will needlessly hinder their use of MRI when treating patients. The European Union Physical Agents Directive, set to become law in April 2008, is aimed at protecting workers in telecommunications and the electricity industry from possible health risks caused by exposure to electromagnetic radiation. Strong fields can induce a current within tissues, which heats them up and may cause damage. Some controversial studies have suggested that such fields may also damage DNA. But the rules will also keep doctors away from MRI machines, which are another source of electromagnetic radiation. This will prevent nervous patients from being accompanied during scans, and may even restrict proper cleaning of the devices. MRI scanners are not dangerous, and that although the electromagnetic frequencies from these devices can gently heat tissues and stimulate nerves in the spine, this does not lead to damage because the heating effects are miniscule. MRI scans have been used to see inside the human body since the beginning of the 1980s, with no known ill effects. Any firm evidence of adverse effects from standing next to a scanner is sparse : unpublished conference abstracts may have fuelled the directive and the advisory guidelines that precede it. Doctors are right to point out the lack of clear evidence of harmful effects, but we are dealing with a new technology and perhaps a bit of caution is necessary. We can't rule out any long-term effect. The directive will turn the UK's current advisory guidelines into law. These guidelines are based on the advice of the International Commission on Non-ionizing Radiation Protection and the National Radiological Protection Board (NRPB). Researchers say these guidelines are also strict, but few people have complained as they are only voluntary. The patients most affected by the changes will probably be anxious children and patients requiring specialized heart investigations. In the absence of a comforting hand, scared children may undergo more harmful but less intimidating X-ray imaging. And nervous patients may have to be anaesthetized before being scanned, subjecting them to an unnecessary risk. Certain heart procedures may also face difficulties. In cardiac catherization, for example, a doctor uses an MRI scan to help guide a tube up the patient's leg to their heart. This would not be possible if the doctor was not allowed in the scanning room. Cleaning the magnet will also be a problem, as technicians will no longer be allowed to get near the magnet. Technicians have been advised to clean the magnet with a sponge on a stick. Given the risk of superbugs, Keevil is horrified at this prospect. Several leading experts in the UK have written to the Secretary of State for Health, requesting 2 years to do research that will justify relaxing the limits in the directive.
• particulated radiations
• neutrons
• slow or thermic neutron : E < 1 MeV
• fast neutron
Sources :
• uranium fission
• cyclotron : large, electrically powered machine that produces neutrons by smashing accelerated deuterons into ³H or Be targets => H⁺, ions with E = 60-300 MeV
• ¹H⁺ (proton) :

Sources : cyclotron
Properties : high LET, straight trajectory, gradual decay =>
• ²H⁺ (deuteron : i.e. proton + neutron) :
• a radiation (⁴He²⁺). E < 3 MeV. Only isotopes with Z > 82 and A > 200 may give such a decay.

Sources :
• cyclotron
• radioisotopes
• b⁺radiation (antielectrons) : only isotopes in which n/p < 1 give such a decay.

Sources :
• radioisotopes
• b^-radiation (electrons) : only isotopes in which n/p > 1 give such a decay.

Sources :
• linear accelerator (LINAC)
• betatron
• radioisotopes
Properties : unelastic collisions => deviated trajectory, high LET, uniform dose in successive layers and sudden decay => ideal for radiotherapy
• meson (p^-) radiation : a short-lived subatomic particle of a mass usually less than that of a proton but more than that of an electron; it may carry either a positive, a negative, or a neutral electric charge.

Sources : smashing accelerated protons into beryllium targets
Properties : ionization density is maximal in depth => ideal for in-depth radiotherapy
• cosmic rays : low fluxes of energetic heavy ions which may be galactic, solar or terrestrial, left over from the Big Bang : during a spacewalk, an astronaut is hit by about 27 times as many cosmic particles than a person on Earth. Matroshka, an 80-kilogram limbless, life-sized mannequin made of natural bone and plastics of various densities that serve as fake organs, will test the human body's exposure received by individual organs in the International Space Station. The doll is coated with a carbon-fibre covering that blocks ultraviolet radiation and deflects space debris, much as a space suit protects a live astronaut. And it has strategically placed radiation sensors to measure cosmic-ray doses to the stomach, lungs, kidneys, colon and eyes. It's because of all these layers that the mannequin is named after the famous hollow Russian dolls that open up to reveal ever-smaller versions of themselves inside. It is expected to spend a year strapped to the outside of the station's Russian Zvezda module, starting on 26 February. During that time, Matroshka will receive three times more radiation than a professional radiation worker's annual dose. Most spacecraft are made of aluminium, through which cosmic rays can easily pass. A round-trip to Mars would take more than two years - far longer than the record 679 days spent on Russia's Mir space station by cosmonaut Valery Polyakov in 1994-95
Sources
• radioactive heavy metals in the fallout nuclear bombs and in waste from nuclear power plants. The chemicals may also be used in a "dirty bomb", a conventional explosive device that contains a small amount of radioactive materials.
• ⁵⁶Mn (biologic t_1/2 = 5.7 days)

Sources : reactors, research laboratories
Exposure type : external, internal
Mode of contamination : not available
Focal accumulation in body : liver
Treatment : not available
• ⁶⁰Co (biologic t_1/2 = 9.5 days)

Sources : medical radiotherapy devices, commercial food irradiators
Exposure type : external, internal
Mode of contamination : lungs
Focal accumulation in body : liver
Treatment : gastric lavage, purgatives, penicillamine in severe cases
• ⁹⁰Sr (biologic t_1/2 = 18,000 days)

Sources : fission product of uranium
Exposure type : internal
Mode of contamination : moderate GI tract
Focal accumulation in body : bones, similar to calcium
Treatment : aluminum phosphate gel (PO 100 ml once immediately after exposure to decrease gut absorption) strontium, calcium, ammonium chloride
• ⁹⁹Mo (biologic t_1/2 = 3 days)

Sources : hospitals - scans
Exposure type : external, internal
Mode of contamination : not available
Focal accumulation in body : kidneys
Treatment : not available
• ^99mTc (biologic t_1/2 = 1 day)

Sources : hospitals - scans
Exposure type : external, internal
Mode of contamination : IV administration
Focal accumulation in body : kidneys, total body
Treatment : potassium perchlorate to reduce thyroid dose
• ¹³⁷Cs (biologic t_1/2 = 70 days)

Sources : medical radiotherapy devices
Exposure type : external, internal
Mode of contamination : lungs, GI tract, wounds, follows potassium
Focal accumulation in body : renal excretion
Treatment : ion-exchange resins, Prussian blue (PO 1 g tid with 100-200 ml water, up to 10 g/d) for >= 3 weeks titrated by urine and fecal bioassay and whole-body counting), chelation therapy
• ¹⁴⁴Ce
• ¹⁵³Gd (biologic t_1/2 = 1,000 days)

Sources : hospitals
Exposure type : external, internal
Mode of contamination : not available
Focal accumulation in body : not available
Treatment : not available
• ¹⁹²Ir (biologic t_1/2 = 50 days)

Sources : commercial radiography
Exposure type : external, internal
Mode of contamination : not available
Focal accumulation in body : spleen
Treatment : not available
• ²²⁶Ra (biologic t_1/2 = 16,400 days)

Sources : instrumental illumination, industrial applications, old medical equipment, former Soviet Union military equipment
Exposure type : external, internal
Mode of contamination : GI tract
Focal accumulation in body : bones
Treatment : MgSO₄ lavage, ammonium chloride, calcium alginates
• ³H (biologic t_1/2 = 12 days)

Sources : luminescent gun sights, muzzle-velocity detectors, nuclear weapons
Exposure type : internal
Mode of contamination : inhalation, GI tract, wounds
Focal accumulation in body : total body
Treatment : dilution with controlled water intake (PO > 3-4 L per day for 3 weeks), diuretics
• ¹³¹I (biologic t_1/2 = 138 days)

Sources : reactor accidents, thyroid ablators
Exposure type : internal
Mode of contamination : inhalation, GI tract, wounds
Focal accumulation in body : thyroid
Treatment : p.o. potassium/sodium iodide (130 mg/d for adults > 40 with thyroid exposure > 500 cGy; 130 mg/d for adults 18-40 with thyroid exposure > 10 cGy, 130 mg/d for pregnant or lactating women with thyroid exposure > 5 cGy; 65 mgd for children and adolescents 3-18 with thyroid exposure > 5 cGy, 16 mg/d for neonates from birth to 1 month with thyroid exposure > 5 cGy) for 7-14 days, propylthiouracil, methimazole
• ²³⁵U (biologic t_1/2 = 15 days)

Sources : depleted uranium, natural uranium, fuel rods, weapons-grade material. 230,000 tons of nuclear waste: that’s how much toxic metal can accumulate after 30 years of mining uranium - and that’s just one waste pile. With all the nuclear waste production throughout the world, this toxic metal is literally “piling up” in more and more places, and is encroaching on inhabited areas. During the process of generating nuclear power and nuclear weapons, radionuclides like uranium are discharged into the environment. These metals pose a serious ecological and health threat and usually contaminate the soil, sediment, and waters surrounding the waste piles. Conventional methods of cleaning up these toxic wastes are often expensive and not very effective. The environment is in dire need of a novel approach to waste clean-up and researchers in Germany may have the answer. Bioremediation is a process that uses microorganisms to return an environment back to its original condition after it has been exposed to contaminants. Nuclear waste pilesare a reservoir for certain strains of bacteria. These bacteria have evolved special mechanisms to survive in this waste that would normally be toxic to other types of microorganisms. The strain Bacillus sphaericus has evolved a crystalline surface layer (S-layer) that covers the outside of the cell. This layer is more than a protective barrier to the bacteria, it serves to accumulate high amounts of toxic metals such as uranium, lead, copper, aluminum, and cadmium. Researchers are currently seeking out ways to exploit the bacteria’s strategies. New technology is incorporating the S-layer structure onto silicon wafers, metals, polymers, nanoclusters, and bioceramic discs. All of these products could be used to remove metals from contaminated water and soil. Additionally, these technologies could be used to recover precious metals such as platinum and palladium from industrial waste sites and recycle them for making electronic products. Bacteria may be the template for new technology aimed at nuclear waste removal. The time may be near when synthetic S-layer discs can be placed in contaminated areas and act as sponges, cleaning up a big toxic mess (Pollman, Biotechnology Advances)
Exposure type : internal
Mode of contamination : GI tract
Focal accumulation in body : kidneys, bones
Treatment : NaHCO₃ (IV 2 ampules 44.3 mEq each, 7.5% in 1000 ml NS, 125 ml/l, or 1 ampule 44.3 mEq, 7.5% in 500 ml NS, 500 ml/h; PO 2 tablets every 4 h until urine pH = 7-8, or 4 g (8 tablets) 3 tid; usually IV for the first 3-4 hours, PO for additional 2 days; continuation of treatment for > 3 days is rare and can be done according to titration of uranium amounts in the body), chelation with EDTA
• ²³⁸U / depleted uranium (DU) (biologic t_1/2 = 15 days), a waste product of ²³⁸U enrichment, is a heavy metal that is 1.6-1.7 times denser than lead. The natural ²³⁵U/²³⁸U isotope ratio is 0.007222.

Sources :
• several civilian applications
• military applications (armor-penetrating munitions, military vehicle armor, and aircraft, ship and missile counterweighting/ballasting). Recent combat applications of DU alloy [i.e., 1991 Persian Gulf War (PGW) and Kosovo peacekeeping objective] resulted in human acute exposure to DU dust, vapor or aerosol, as well as chronic exposure from tissue embedding of DU shrapnel fragments. DU alloy is 99.8% ²³⁸U, and emits approximately 60% of the a, b, and g radiation found in natural uranium (4.05 x 10^-7 Ci/g DU alloy). During the Gulf conflict, Abrams tanks, Apache attack helicopters and A-10 tank-buster planes fired an estimated 300 tonnes of DU munitions : it was claimed to contribute to health problems such as acute myeloblastic leukemia (AML) and the so-named Gulf War syndrome / Balkan syndrome.
Pathogenesis : the radiological and chemical properties of DU can be compared to those of natural uranium, which is ubiquitously present in soil at a typical concentration of 3 mg/kg. Natural uranium has the same chemotoxicity, but its radiotoxicity is 60% higher.
• due to the low specific radioactivity and the dominance of a-radiation no acute risk is attributed to external exposure to DU
• the major risk is DU dust, generated when DU ammunition hits hard targets. Depending on aerosol speciation, inhalation may lead to a protracted exposure of the lung and other organs. After deposition on the ground, resuspension can take place if the DU containing particle size is sufficiently small. However, transfer to drinking water or locally produced food has little potential to lead to significant exposures to DU
It can remain within the body for many years and slowly solubilize. High levels of urinary uranium have been measured in PGW veterans 10 years after exposure to DU fragments and vapors.
Laboratory examinations : since poor solubility of uranium compounds and lack of information on speciation precludes the use of radioecological models for exposure assessment, biomonitoring has to be used for assessing exposed persons : urine, feces, hair and nails record recent exposures to DU.
Symptoms & signs :
• in rats
• there is strong evidence of DU accumulation in tissues including testes, bone, kidneys, and brain
• in vitro tests indicate that DU alloy may be both genotoxic and mutagenic
• in vivo study suggests that tissue-embedded DU alloy may be carcinogenic in rats. T
• about 116 in every 100,000 people were diagnosed in 2001 with cancer in the vicinity of Basra in southern Iraq, where the U.S. military used DU shells in the Persian Gulf War in 1991 : the number marks a 10-fold increase from the 11 cases diagnosed in 1988. An increasing number of families have members who are suffering from cancer, and the death toll from the disease has risen 19-fold during the same period. In 2001, 611 babies were born with no limbs, no eyes or other birth defects, compared with 37 such cases in 1990
• there is limited available data for reproductive and teratological deficits from exposure to uranium per se, typically from oral, respiratory, or dermal exposure routes. Alternatively, there is no data available on the reproductive effects of DU embedded
Prevention : adding acetate into contaminated underground aquifer stimulates the growth of Geobacter spp., which convert soluble uranium to insoluble uraninite, which stays put instead of mixing with water used for drinking or irrigation (70% in 50 days)
Treatment : NaHCO₃ (IV 2 ampules 44.3 mEq each, 7.5% in 1000 ml NS, 125 ml/l, or 1 ampule 44.3 mEq, 7.5% in 500 ml NS, 500 ml/h; usually IV for the first 3-4 hours, PO for additional 2 days; continuation of treatment for > 3 days is rare and can be done according to titration of uranium amounts in the body), chelation with EDTA
• ₉₄²³⁹Pu (biologic t_1/2 = 73,000 days)

Sources : produced from uranium in reactors, nuclear weapons
Exposure type : internal
Mode of contamination : limited lung absorption, high retention
Focal accumulation in body : lungs, bones, bone marrow, liver, gonads
Treatment : chelation therapy with Zn- or Ca-DTPA (IV 1 g in 250 ml NS or 5% glucose, given in 1-2 h, or bolus over 3-4 min; inhalation 1 g in 1:1 dilution with water or NS over 15-20 min; IM 1 g not recommended because of pain) for up to 5 days or EDTA
• ²⁴¹Am (biologic t_1/2 = 73,000 days)

Sources : smoke detectors, nuclear weapon detonation fallout
Exposure type : internal
Mode of contamination : inhalation, skin wounds
Focal accumulation in body : lungs, liver, bones, bone marrow
Treatment : chelating with Zn- or Ca-DTPA (IV 1 g in 250 ml NS or 5% glucose, given in 1-2 h, or bolus over 3-4 min; inhalation 1 g in 1:1 dilution with water or NS over 15-20 min; IM 1 g not recommended because of pain) for up to 5 days or EDTA
• ₉₅²⁴³Am

Chelation therapy
• ²¹⁰Po (biologic t_1/2 = 60 days)^ref

Sources : calibration source. Po-210 is used in some devices to get rid of static electricity in processes such as rolling paper, manufacturing sheet plastics, and spinning synthetic fibers. These devices are strictly regulated and are usually only available for lease rather than purchase. Specifications available on manufacturers' websites suggest that they contain enough polonium-210 to kill someone. Polonium 210 is used as a heat source or power supply for satellites.
Exposure type : internal
Mode of contamination : inhalation, wounds
Focal accumulation in body : spleen, kidneys
Even in milligram or microgram amounts, handling polonium-210 is extremely dangerous, requiring specialized equipment and strict handling procedures. a particles emitted by polonium material are absorbed by the body and will damage organic tissue easily if ingested or absorbed (though they do not penetrate the epidermis and hence are not hazardous if the polonium is outside the body). Pierre and Marie Curie discovered the element and they named it after their country of Poland and radium. For this discovery they won the Nobel Prize. Their daughter Irene is believed to have died from cancer related to Polonium, which she was exposed to after an explosion in her laboratory. It was 15 years before the cancer took her life. Although her cancer and subsequent death are believed to have been related to the explosion and possible exposure to the element, there remain questions. For example, did a piece of Polonium 210 contaminated glass penetrate the skin of Irene?
The maximum allowable body burden for ingested polonium is only 1100 Bq (0.03 µCi), which is equivalent to a particle weighing only 6.8 × 10^-12 g. Weight for weight polonium is approximately 2.5 × 10¹¹ times as toxic as hydrogen cyanide. The maximum permissible concentration for airborne soluble polonium compounds is about 7,500 Bq/m³ (2 × 10^-11 µCi/cm³). Polonium has been found in tobacco smoke from tobacco leaves grown at some specific places, as a contaminant^{ref1, ref2} and in uranium ores. At a committed effective dose equivalent (CEDE) of 5.14×10^-7 sieverts per becquerel (1.9×103 mrem/µCi) for ingested ²¹⁰Po and a specific activity of 1.66×10¹⁴ Bq/g (4.49×10³ Ci/g)^ref the amount of material required to produce a lethal dose of 10 sieverts would be only 0.12 mg or about 525 mCi. The biological halflife is 50 to 30 days in humans^ref. The polonium-210 isotope has a half-life of 138 days and it decays to lead-206, which is stable, by emitting an a particle. Crystal of Polonium 210 the size of 0.35 mm crystal of sugar, cubic in shape would weigh 3.9428 x 10^-4 grams. This exceeds lethal dose some 3370 times (3369.9017).
Polonium-210 caused the death of 43-years old Alexander Litvinenko on November 23, 2006^ref : this Russian man was a former member or Russia's secret service (KGB), nowadays renamed the Federal Security Service (FSS). He had become a British citizen and an outspoken critic of President Vladimir Putin. He was investigating the murder of journalist Anna Politkovskaya, a strident critic of the Russian government. Before dying, he accused the Kremlin chief of ordering his killing. Traces of polonium were found in his urine, as well as in several locations he had visited shortly before becoming ill^ref.
• on Nov 1 he met at the Pine Bar of the Mayfair Millennium Hotel, in Grosvenor Square close to the American Embassy with 3 spies :
• 41-years old private security agent Dmitry Kovtun : he was reported Friday to have a "serious form of radiation sickness" that was affecting his critical organs: the liver, kidneys and bowels. The Interfax news agency reported that Mr. Kovtun fell into a coma "practically immediately upon completion of the interrogation" by British and Russian investigators, who questioned him in Moscow as an attempted murder for a 3rd day in connection with Mr. Litvinenko's murder, although he had since regained consciousness. Interfax cited unnamed sources. Later on, a lawyer connected to the case, Andrei Romashov, told Reuters that Kovtun's  health was unchanged and satisfactoryas any deterioration in his condition. Kovtun also claimed in an interview with Germany's Spiegel TV that he must have been contaminated during meetings with Litvinenko and Lugovoi in London in mid-October 2006. Meanwhile, German investigators are investigating Kovtun on suspicion that he may have illegally handled radioactive material. German authorities have found traces of polonium-210 in several locations visited by Kovtun before he traveled to London on 1 Nov 2006. They say Kovtun flew to Hamburg from Moscow on 28 Oct 2006 and departed for London on 1 Nov 2006. Traces of polonium-210 have been found on the passenger seat of the car that picked up Kovtun from the Hamburg airport. German officials believe that Kovtun already was contaminated when he arrived in Hamburg^{ref1, ref2}. Police said that traces of a radiation had been found at the homes in and near Hamburg of the ex-wife and the former mother-in-law of Dmitry Kovtun. Kovtun's 31 year old former wife, her 27 year old boyfriend and her 2 children, ages one and 3, were sent to a Hamburg hospital on Mon 11 Dec 2006 for further tests on "suspicion" of being contaminated, Hamburg police said. German news reports said polonium-210 was found in the bedrooms of the ex-wife's home, on the children and on the family's clothes. German officials said Sun 10 Dec 2006 that Kovtun spent the night of 28 Oct 2006 at his ex-wife's apartment and that they had found polonium-210 on the couch where he slept. They also said traces of polonium-210 were found in a BMW that Kovtun rode in from the airport after flying in from Moscow earlier that day. Officials said Mon 11 Dec 2006 that they had found traces in a 2nd car, a Chrysler, which he rode in twice between 28 Oct and 1 Nov 2006. Police are also seeking to find the taxi driver who drove Kovtun to the airport for a 0640 Germanwings flight to London on 1 Nov 2006. In Moscow on Mon 11 Dec 2006, British detectives talked with businessman and former KGB officer Andrei Lugovoy, who with Kovtun met Litvinenko on 1 Nov 2006 at the Millennium Hotel in London^ref
• Andrei Lugovoi (friends since they were 12 year olds) is also in the same hospital as Mr. Kovtun but his condition is unclear. Lugovoi said in an interview with the Moskovsky Komsomolets newspaper that he thinks Litvinenko may have been poisoned 2 weeks earlier, on the day he and Lugovoi met Kovtunt in the office of a security company in London on 16 Oct 2006. After British authorities, meanwhile, discovered traces of polonium-210 in the security company offices.
• all 7 bar staff tested positive for polonium-210^ref. HPA was assessing staff who worked in the hotel's Pine Bar between 31 Oct and 2 Nov. Around 250 people who were in the bar on 1 Nov 2006 contacted the advice line and were invited to make a urine test
• he also ate at the Itsu sushi restaurant on the same day, although it is not clear which establishment he visited first. There he met Mario Scaramella, an Italian security consultant, who wanted to show Litvinenko emails from a mutual source warning both their lives may be in danger. He said Litvinenko had told him not to worry. He has denied poisoning Litvinenko himself : Scaramella tested positive for traces of radioactivity, but have developed no signs of illness
• Mr. Litvinenko's wife tested positive
• A female adult relative of poisoned Russian Alexander Litvinenko has been exposed to radioactive polonium 210 but is not in any short-term danger. Yegor Gaidar, who served briefly as prime minister in the 1990s under Russian President Boris Yeltsin, vomited and fainted during a conference in Ireland on 24 Nov 2006, a day after ex-KGB agent Alexander Litvinenko died of radiation poisoning. Doctors treating Gaidar in Moscow think he also was poisoned, said his spokesman, Valery Natarov. Gaidar, 50, was feeling better Thursday, according to Natarov^ref.
Litvinenko fell ill on 1 Nov 2006, and was immediately admitted to hospital. The hunt for whatever ailed him was on. His symptoms were consistent with something that was making his cells stop dividing. Some chemicals can do this. At first thallium was reported as the prime suspect (by the press, at least — it was declared "unlikely" by the hospital treating him). This heavy metal is sometimes called the 'poison of choice' for its colourless, tasteless qualities, and the small amount (about 1 g) needed to kill. Then hair loss pointed, potentially, to a radioactive element. Speculation about the possibility of radioactive thallium took off. It wasn't until after Litvinenko's death on 23 Nov 2006 that the true culprit was announced: on the morning of 24 November, Britain's independent Health Protection Agency declared that a significant amount of the radioactive isotope polonium-210 had been found in his body. TOXBASE, for use by doctors in the United Kingdom, helps by listing the symptoms of different toxins. So once you suspect thallium, you could use this to see that this heavy metal usually causes neurological problems, and perhaps rule it out. You'd also, at that point, do a mass spec of urine and blood to look for the suspect element — presuming that it wasn't a 'hit and run' exposure in which the poison would already have passed from the system. Why, at that point, polonium-210 didn't leap off the page is still a mystery to me. Maybe it did. The hospital where Litvinenko died is understandably no longer taking calls from the media — the doctors are too busy saving lives. It might not have mattered much if the culprit was spotted early, it turns out. I ask whether you can do anything for someone with polonium poisoning: No. Nothing. Radiation is nasty stuff. He remembers one case of a man in Brazil who bought a radiation treatment device from a scrap yard, and took the 'pretty' active source home for his kids to play with. He managed to kill himself and quite a few members of his family. Litvinenko died on Nov 23 2006. Earlier on Fri Dec 1, 3 pathologists wearing protective suits to guard against radiation carried out a post-mortem on Litvinenko at the Royal London Hospital. On Thursday, about 50 friends and family members of Mr Litvinenko attended his funeral at Highgate Cemetery in north London. Among them were some of the most prominent Russians living in self-exile from Mr. Putin's Russia: Boris A. Berezovsky, an erstwhile ally of Mr. Putin who fled what he has called politically motivated criminal charges, and Akhmed Zakayev, a leader of Chechnya's foundering separatist movement. Alex Goldfarb, an associate of Mr. Berezovsky and spokesman for the Litvinenko family, said later that the funeral at Highgate Cemetry -- the burial place, among others, of Karl Marx -- had taken an unexpected turn when, against the wishes of Marina Litvinenko, the widow, a Muslim cleric performed Islamic rites. "It was supposed to be a nonreligious, nondenominational ceremony according to the wishes of the widow. Unfortunately, some people appeared and against the explicit wishes of the widow performed Muslim rites over the funeral," Mr. Goldfarb said. "We had a choice to turn it into an unseemly situation, but Marina asked us to respect the memory of Alexander and let these people do what they did. Let God be their judge," Mr. Goldfarb told the British news agency that Press Association. He could not immediately be reached for further comment. "I do not know what Alexander wanted. Akhmed believes that he converted to Islam on his deathbed, but I have strong reservations," Mr. Goldfarb said, referring to Mr. Zakayev, the Chechnyan leader.
The prosecutor general, Yuri Y. Chaika, said Russia would remain in charge of any detective work here and would try any suspects in Russian courts, but Russian investigators have cooperated with their British counterparts who arrived on Monday as part of their investigation. Traces of radiation were found at 12 sites and aboard planes which have carried > 33 000 passengers in the past month, many flying between London and Moscow. It is possible that Litvinenko spread tiny amounts of polonium-210 after being poisoned. It was technically possibly for polonium to be carried in tobacco smoke, where minute traces are routinely found in nature, but the levels of contamination in the bar workers did not signified that the toxins had been inhaled in cigarette smoke. The substance could have come out in his sweat or tears, for example. The Times newspaper said Friday it could have been inhaled from vapour evaporating from a contaminated drink or ice cube or by breathing in poisoned cigarette smoke. You can breathe it in if there are large volumes of it around. But the amount you would take in that way would be very small. The agency has repeatedly stressed that the danger of contamination to the wide public is negligible. The amounts of polonium in tobacco smoke are normally "trivial". "The sort of things we're hearing about the various amounts of polonium in various workers is much greater than you could have got from smoking normally. But he rejected the theory of inhaling vapour from a contaminated drink. You might get very faint traces, but they would be comparable with (traces from) smoking. It just doesn't evaporate in significant quantities. I don't think that anything that was in a drink would get into the air and be breathed in by bar staff. It would be more volatile from a hot drink, such as tea, there would be more possibility but even then, it's a little bit far-fetched." Instead, he suggested there was a common route, perhaps from a liquid aerosol in the bar or dust, but that would not be guaranteed to hit a specific target. It could have been put in a drink, perhaps an ice cube, which would have contaminated the bar staff, they'd be picking up the glass, tipping the drink down the sink, and they could easily get their hands contaminated. Bar staff could then have contaminated themselves by rubbing their eyes, touching their nose or mouth or eating food with their bare fingers. Theories about the planes that have been grounded after finding hints of radiation on board are even more speculative. Authorities have not said what level of radiation has been detected or even whether the source is polonium-210. If polonium-210 is found to be the source, further questions need to be answered. If the polonium-210 was brought from Russia, as many observers have speculated, contamination could easily have been prevented by simply keeping it in a tightly sealed bottle. Careful washing will remove most external traces of Po-210^ref. Normal hygiene practices in hospitals for microbial contamination will protect workers from radiological contamination^ref. As of 4 Dec 2006, the U.K. Health Protection Agency has stated that there have been no issues of public health concern to British Airways passengers^ref. In addition, the U.K. Health Protection Agency reported that the Ashdown Park Hotel and Best Western Hotel, Shaftesbury Avenue, in London have been checked and no public health concern has been found. A potentially affected area in the Emirates Stadium has been checked, and there is no risk to public health.
Scientists at UK Atomic Weapons Establishment (AWE) had traced the source of the polonium to a nuclear power plant in Russia. Russia produces only 8 g of polonium 210 a month. All goes to U.S. companies through a single authorized supplier. Nuclear reactors like the Russian RMBK or the Canadian CANDU were needed to make it. However Atomic Energy of Canada Limited (AECL), the company that makes CANDU reactors, said the plants could not produce polonium : the reactors burned natural uranium while polonium 210 was produced using bismuth as a fuel source^ref1,ref2. The production can be done in a nuclear reactor by bombarding bismuth-209 with neutrons. This initially forms the radioactive isotope bismuth-210, which has a half-life of 5 days, decaying to polonium-210 by b decay. Contrary to initial reports, the radioactive substance that last month killed Alexander Litvinenko could probably be obtained by someone without contacts at nuclear reactors, the sites at which polonium-210 is manufactured. In the USA, tiny amounts can be bought from various supply companies — but one would need to buy thousands in order to amass a dangerous dose. How much was used to kill Litvinenko? No one knows for sure, but the time he took to die — around 3 weeks after being admitted to hospital — gives a rough clue.  Data from survivors of the Hiroshima and Nagasaki bombs, as well as from nuclear accidents, suggest that a dose of more than 15 sieverts kills within days, as the radiation destroys gut tissue. People exposed to < 5 Sv usually live for longer than three weeks and may even survive the initial poisoning. A dose within the range of 5-15 Sv is equivalent to the amount of radiation received by someone standing within 800 m of the Hiroshima bomb. If ingested, perhaps as little as 0.1 mg of polonium-210 could deliver this dose. Estimates on the lethal dose vary widely.
Treatment : lavage, dimercaprol
• ²⁰⁴Tl (see also chemotoxicity)

Chelation therapy
• ²³²Th (biologic t_1/2 = 73,000 days)

Sources : calibration source
Exposure type : internal
Mode of contamination : not available
Focal accumulation in body : not available
Treatment : not available
• ³²P (biologic t_1/2 = 1,155 days)

Sources : research laboratories, medical facilities
Exposure type : internal
Mode of contamination : inhalation, GI tract, wounds
Focal accumulation in body : bones, bone marrow, rapidly replicating cells
Treatment : lavage, aluminum hydroxide (PO 60-100 ml once to decrease gut absorption), phosphate
• ₉₆²⁴⁷Cm

Chelation therapy
• human body : ¹⁴C, ⁴⁰K
• Earth : ²²⁶Ra => ²²²Rn, ²²⁸U, ²³²Th, ²³⁵U
• radium necrosis : necrosis of bones due to exposure to radium, formerly common in workers in radium plants.
• atomic explosions
• dirty bomb : some officials and nuclear experts say that although radiation from a dirty bomb could cause vast psychological and economic damage, it would result in few, if any, deaths. They argue that the radioactive material contained in the bomb would be too diluted after the blast to expose any one person to a deadly dose. A new analysis of an incident in Goiâna, Brazil, where scrap-metal merchants took a canister containing 1,400 curies of radioactive caesium-137 from an abandoned cancer clinic. Not knowing what the glowing dust was, they dispersed about 10% of it at a party, during which over 150 people inhaled or swallowed the material : 6 people in the area died as a result of the incident, 3 of whom were not at the party and had had no direct contact with the material. Using those numbers, it has been estimated that if a bomb dispersed a similar amount of material over a wider area, as many as 150 people could die and 1400 could become ill. The Goiâna incident is particularly disturbing because it is unclear how some of the victims became contaminated, which suggests that even indirect contact with the material was enough to kill them : however the Goiâna victims did not receive treatment until several days after their exposure and the death toll from a dirty bomb might be lowered considerably if victims who ingested or inhaled material were treated immediately following the blast.
Web resources : United Nations Scientific Committee On the Effects of Atomic Radiation (UNSCEAR)

• Baumé's scale : a scale for expressing the specific gravity of liquids, based on the extent to which the liquid is lighter or heavier than water
• hydrometer scale : a scale used for expressing the specific gravity of liquids
• pressure units
• acoustic radiations
• infrasound radiations (n < 8 Hz)
• sound radiations (20 < n < 20,000 Hz) : mechanical radiant energy, the motion of particles of the material medium through which it travels (gas, liquid, or solid) being longitudinal along the line of transmission; such energy provides the stimulus for the subjective sensation of hearing
• continuous sounds
• discontinuous sounds
• stable sounds
• fluctuating sounds
• intermittent sounds
• impulsive sounds (very short and intense) : e.g. explosion, ...
Sources are far more common in crowded cities of Westernized countries :
• lower threshold for auditory ability = 0 dB
• silent room = 20 dB
• isolated room = 50 dB
• normal conversation = 65 dB
• utensile device = 80 dB = danger threshold
• electrical engine for refrigerator = 88 dB
• press = 95 dB
• spray varnishing = 105 dB
• circular saw = 110 dB
• gross polishing = 115 dB
• pain threshold = 125 dB
• TLV-ceiling = 140 dB
• near taking off airplane = 145 dB
• maximum SPL = 194 dB
• occupational exposure
• entertainements (disco, sub, hunting, moto sports, walkman, ...)
Pathogenesis :
• acute high-intensity sounds : eardrum displacement => rupture of eardrum and/or ossicles chain => bilateral transmissive hearing loss
• chronic low-intensity sounds : damage of Corti's organ => bilateral perceptive hearing loss beginning with high frequencies (peak at 4,000 Hz) and then involving also so-called "social frequencies" (250-2,000 Hz)
Symptoms & signs : depend on SPL and duration of exposure
• auditory damage
• acute acoustic trauma from acute exposure to impulsive sounds : monolateral injury to tympanus +/- hairy cell, violent otalgia, hypoacusis with acuphems and vertigo. Exposure > 160 dB, even for a very short time, almost invariably cause tympanic rupture.

Laboratory examinations : audiometry : transmissive or mixed hypoacusis, usually monolateral and reversible
• chronic acoustic trauma from prolonged exposure to SPL > 80 dB => bilateral and symmetric injury to Corti's organ cells developing in 5-20 years, irreversible but not evolutive once exposure is removed.

Stages :
• 1 : at first exposure : high-tone acumphems, sensation of full ear, headache and obtuseness, at the end of the work shift, then symptoms attenuate
• 2 : lasting months to years, asymptomatic, rarely acuphems), audiometry marks fall at 4,000 Hz and recovery at 8,000 Hz
• 3 : symptomatic hypoacusis (can't listen to watch tic-tac, turn up the volume of radio and TV to understand speeches); audiometric deficiency at 4,000 Hz may reach 45-60 dB
• 4 : noise deafness some years after stage 3; difficulty listening to voices, persistent acuphems, distorted sounds due to recruitment phenomenon; raised auditory threshold at 3,200, 4,000-6,000 Hz and 8,000 Hz (spoon-shaped curve)
Laboratory examinations : perceptive hypoacusis progressively involving frequencies lower than 4 kHz
• on apparatuses other than auditory one due to stimulation of autonomic nervous system :
• peripheral vasoconstriction, decreased cardiac output, tachycardia, extrasystoles and paroxysmal systemic arterial hypertension in cardiopathic patients after 90 dB for 10'
• tachypnea (increased by 10-30%) at SPL > 85 dB, even during sleep
• endocrine systems : hyperpituitarism, hypoadrenalism, hyperthyroidism, and hypogonadism
• mydriasis => difficult depth evaluation when SPL > 75 dB. At SPL = 110-120 dB, reduced visual field for red colour and impaired night vision (dangerous for night drivers listening to high-volume radios)
• psychological reactions : concentration deficit, mental fatigue, insomnia (SPL = 70 dB cause 33% of awakenings and less deep sleep) => depression, irritability, intolerance, decreased vigilance, delayed reaction times, causing a 20% increased energy expenditure.
• urinary and menstrual disorders in adults; decreased fertility and libido; underweight deliveries
• slowed down EEG rhtyhms, reduced reflexes and fixation memory, vasoconstriction-induced headache
• functional alterations of gastrointestinal apparatus : dyspepsia, spasms and cramps; hyperchlorhydria => gastritis => peptic ulcer, colitis
Laboratory examinations :
• phonometer (microphone, registration and elaboration unit, lecture unit) simulating human ear
• pure sound pressure level (SPL) [dB]
• equivalent sound pressure level (SPL) (Leq) [dB] : average sound level of variable sound levels to which the worker is exposed in the given time interval
• level of exposure of a person (Lep) : total sound energy absorbed by the worker
• level of exposure of a person per day (Lep,d) (LEX8h)
• level of exposure of a person per week (Lep,w)
• LCPeak
• Lmax
• Lmin
• Ln values such as L10, L50 and L90
• audiometry.
• Klochoff system :
• Merluzzi's classification :
• 1 : deep at 4,000 Hz
• 2 : deep at 4,000 and 3,000 Hz
• 3 : deep at 4,000, 3,000 and 2,000 Hz
• 4 : deep at 4,000, 3,000, 2,000, and 1,000 Hz
• 5 : deep at 4,000, 3,000, 2,000, 1,000 and 500 Hz
• 6 : mized hypoacusis (noise and other causes)
• 7 : hypoacusis due to a cause other than noise
Differential diagnosis : nosoacusis from other disease, age-related presbyacusis
Prevention :
• interventions on productive process : newer, more silent technologies (decreased machine concentration in rooms; noisy machines far from walls, separation of noisy devices from the others)
• intevention on noise sources : reprojecting and modify machines : constant manutention, reduced working rhythm or rate (not use machines in extreme conditions), silencesrs over air discharges of pneumatic devices and over compressed air pistols
• use more silent deveices with timely sharpening/replacement; use electrical or oleopneumatic screwers; modify press moulds, chutes, and shears
• intervations on noise propagation (place machines on antivibration supports; close machines and noisy devices into isolating cabinets and chest; place acoustic barriers or phonoassorbing covers to reduce noise spreading towards other working places
• worker's protection interventions : reduce exposure duration with shift to other jobs; stationing cabinets are recommended when the worker has mostly surveillance activities; personal protective equipments
• Lep,d < 80 dB => tolerable exposure, no measure required
• Lep,d = 80 dB = TLV-TWA : periodic measurement and worker information required
• Lep,d = 85 dB : personal protective equipment (PPE) should be available
• ear plugs : cotton has poor effectiveness
• universal modelable ear plugs are hygienic and of low-cost (disoposable in waxed cotton or acoustic fibers; semi-disposable in sponge or foamy material inserted into ear channel under pressure)
• tailored ear plugs created according to the earprint
• universal or personalized premodelled soft-silica, rubber or plustic ear plugs (re-usable after soap-washing, hygienic and long-lasting; lower effectiveness in irregular ear channels and may strengthen because of earwax)
• canular rubber capsules for frequent short-time exposures and workers who can't use ear plugs
• cuffs may decrease SPL of high-frequency noises by 15-30 dB (cuffs+ear plugs are recommended for SPL > 105 dB)
• helmet-coupled cuffs
• dielectrical cuffs without metal component for workers exposed to high-voltages
• electronical cuffs reduce dangerous noises and amplifies desired sounds (e.g. voices)
• foldable cuffs for short-time exposures
• helmets
• Lep,d = 90 dB : as above but yearly check-up including also visual signal check-up; reduce exposure by improving turnation and devices
• ultrasound radiations ( n > 20,000 Hz)

Applications :
• echography
• high-intensity focused ultrasound (HIFU) / focused ultrasound surgery (FUS)
Pathogenesis : the type of ultrasound used to scan babies in the womb disturbs brain cells in mouse fetuses. The finding fuels a debate about the safety of the technique for unborn babies. Babies in the womb are routinely scanned using high-frequency sound waves. The scans allow doctors to check on growth rates and spot developmental abnormalities. Pasko Rakic of Yale Medical School in New Haven, Connecticut and his team were similarly scanning experimental mice, to help inject dye into embryos. When later studying the brain development of these mice, the team noticed that certain neurons in the growing cortex were not behaving normally. Rakic discussed his preliminary results at the Society for Neuroscience meeting in 2004. But he says he wanted more results to be convinced — now, 335 mice later, he is. There is no evidence that ultrasound scanning disrupts the brains of human fetuses. The affected mice in his study were exposed to continuous ultrasound for 30 minutes or more; a baby's brain would be exposed for only a fraction of this time during a 30-minute scan of its entire body. And a narrow ultrasound beam will hit and affect far more of a small mouse brain than a larger human one. Some studies have hinted that ultrasound causes subtle brain changes in humans that increases the chance of a child being left-handed or developing speech problems. Others suggest that the risk is minimal. A 2004 study found that fetuses exposed to five ultrasound sessions rather than one are more likely to grow poorly, but that this difference disappears after the first year^ref. We don't want to push the panic button. It would be very wrong if women stopped having medically indicated ultrasounds because of this. At the same time, it is sensible to avoid the lengthy ultrasound scans that some parents now choose in order to make videos of their baby. The US FDA and other medical groups also discourage unnecessary ultrasound scans. Neurons are born deep inside an embryo's brain cortex and then migrate to the outer edge. This migration creates a series of parallel zones running through the cortex, like rock strata, each of which has specific functions in communicating to other areas of the brain. These layers are vital for the processes directed by the cortex such as memory and language. In animals, alcohol, cocaine and viral infections can also disrupt the neurons' migration and affect behaviour. Rakic marked some of these migrating neurons with a dye and then exposed the growing mice to between 5 minutes and 7 hours of ultrasound over the final three days of gestation, using a machine identical to that used for humans. He then examined the brains of the young mice a few days after birth. In those exposed to 30 minutes or more of ultrasound, not all of the neurons destined for the outer layers of the cortex completed their journey. Instead, some remained scattered in interior layers of cortex, or even in neighbouring white matter. The more ultrasound the mice received, the more scattered their neurons^ref. Neuronal migration was disrupted in a group of animals that went through the experimental procedures for 7 hours, but were not exposed to ultrasound. This suggests that the stress caused by an extended period of handling could also affect the brains of a mother's babies. But stress can't explain all the results. The scientists are not sure how the ultrasound waves disrupt neuron migration. One idea is that they make the neurons vibrate, preventing them from sticking to adjacent cells. Rakic is repeating his experiments in monkeys, and looking for behavioural changes in the offspring. He says he does not yet have results
• dysbarism : a general term applied to any clinical syndrome caused by difference between the surrounding atmospheric pressure and the total gas pressure in the various tissues, fluids, and cavities of the body, or expansion of gases in the hollow viscera.
• föhn ill : headache, weariness, and depression felt during the föhn (a wind from the south in Central Europe)
• hypobarism : the condition resulting from exposure to ambient gas pressure or atmospheric pressures that are below those within body tissues, fluids, cavities.

=> hypobaropathy : the disturbances experienced in high altitudes due to reduced air pressure; see high altitude sickness and mountain sickness
=> chokes : a burning sensation experienced during decompression, beginning in the substernal region, with increasing uncontrollable urge to cough and a feeling of great apprehension, leading to vasovagal attack.
• cutis marmorata is a dermal manifestation of decompression sickness. Initially, there is erythema accompanied by pruritus, and then the rash spreads irregularly and deepens in color. It develops a mottled appearance, with areas of pallor surrounded by cyanotic patches. During recompression, the rash resolves. Although cutis marmorata is not directly associated with complications, it commonly accompanies or precedes more severe illness involving the central nervous system or cardiovascular system and should be identified early in a troubled diver^ref
• hyperbarism : the condition resulting from exposure to ambient gas pressure or atmospheric pressures that exceed the pressure within body tissues, fluids, and cavities. Symptoms remain the same whether it all happens during ascent or descent. Boyle's law is important for the understanding of the pathophysiology of barotrauma.

=> barotrauma : any disease or injury due to unequal pressures between a hollow space inside the body and the ambient pressure, or between 2 spaces within the body
• external ear
• eustachian tube and middle ear (barotitis media / otitic barotrauma / aerotitis media / aviation otitis / aviator's ear / middle ear barotrauma)
• inner ear (aerotitis interna / barotitis interna / inner ear barotrauma)
• paranasal sinuses (aerosinusitis / barosinusitis / sinus barotrauma)
• lung (pulmonary barotrauma)
• pneumomediastinum
• pneumothorax
• arterial gas embolism (systemic air embolism (SAE))
• eyes
• teeth
• gastrointestinal tract
• skin
• traumatopathy (traumatology : the branch of surgery which deals with wounds and disability from injuries) : any pathological condition due to wound or injury

Risk factors : marital separation or divorce was associated with an increased risk of a serious accident (all serious accidents: hazard ratio 2.9, 95% confidence interval = 1.7-5.0; at-fault accidents: 4.4, 2.3-8.3). The impact of separation and divorce did not differ according to alcohol consumption levels. Other life events associated with increased risk of serious accident were a child leaving home (all accidents: 1.2, 0.97-1.6; at-fault accidents: 1.5, 1.1-2.1), an important purchase (all accidents: 1.4, 1.1-1.7; at-fault accidents: 1.6, 1.2-2.1), and hospitalization of the partner (all accidents: 1.4, 1.1-2.0)^ref.
• injury / trauma / wound : harm or hurt; usually applied to damage inflicted on the body by an external force
• blast injury : the injuries caused by an explosion, most commonly
• blast chest
• laceration of other thoracic and abdominal viscera
• ruptured ear drums
• minor effects on the central nervous system.
• deceleration injury : an injury sustained by sudden deceleration in the movement of the body, as in a motor vehicle accident (MVA)
• the brain is especially liable to such trauma
• major decelerational thoracic injuries :
• myocardial contusion
• traumatic aortic disruption (TAD)
• sternal fracture (SF)
• flail chest (FC)
• tracheobronchial disruption (TBD)
• whiplash injury : a popular nonspecific term applied to injury to the spine and spinal cord at the junction of the fourth and fifth cervical vertebrae, occurring as the result of rapid acceleration or deceleration of the body. Because of their greater mobility, the 4 upper vertebrae act as the lash, and the lower 4 act as the handle of the whip.
• steering-wheel injury : injury to the chest and sometimes contusion of the heart in motorists, caused by being thrown forward against the steering wheel
• unintentional injury : in public health, the cause of death when the death occurs under accidental circumstances.
• types of explosions
• conventional bombs
• enhanced-blast explosive devices
• types of blast injuries
• primary blast injuries
• secondary blast injuries
• tertiary blast injuries
• quaternary blast injuries
• trauma : injury; psychological or emotional damage.
• birth injury or trauma : an injury to the infant received in or due to the process of being born 2. in some psychiatric theories, the psychic shock produced in an infant by the experience of being born.
• psychic trauma : a psychologically upsetting experience that produces an emotional or mental disorder or otherwise has lasting negative effects on a person's thoughts, feelings, or behavior.
• concussion : a violent jar or shock, or the condition which results from such an injury.
• contusion / bruise : an injury of a part without a break in the skin and with a subcutaneous hemorrhage

Aetiology : contunding bodies
• natural offeding media : hands, feet, teeth, ..
• natural objects : stones, branches
• instruments : hammers, adjustable spanners, bars, automobiles, ...
• arms : truncheon, fisters, ...
Pathogenesis :
• compression : the act of pressing together; an action exerted upon a body by an external force which tends to diminish its volume and augment its density
• percussion : the act of striking a part with short, sharp blows
• rubbing : to move something over a surface with friction
• traction : the act of drawing or exerting a pulling force, as along the long axis of a structure
Localizations :
• brain contusion
• contusion of spinal cord
• myocardial contusion
• pulmonary contusion
• stone bruise : a painful bruise, especially of the bare feet of children
• skin

Grading :
• excoriation
• irritation : a state of overexcitation and undue sensitivity, manifested as vasocutaneous reaction with pallor, reddening and subsequent pain, as after a slap. Sometimes acute burning with local acute inflammation, even with exudation and formation of vesicles (e.g. by handling cords), sometimes evolving to chronic dermatitis
• direct irritation : irritation due to direct stimulation of a part.
• functional irritation : that which is attended with functional derangement without organic lesion; also overexcitability due to excessive functional activity.
• compression may be reversible or cause stasis, cutaneous hemorrhages, or rhabdomyolysis => lower nephron nephrosis (Bywaters' muscle crush syndrome)
• first grade contusion : ecchymoses
• second grade contusion : hematoma
• third grade contusion : necrosis => granuloma
• contused or nonpenetrating wound
• crack or split wound over bones (e.g. blow over skull)
• exposure wound
• bite wound : bite : a wound or puncture made by the teeth or other parts of the mouth
• severe contusive traumas
• precipitation
• car crush
• blast : the wave of air pressure (air concussion) produced by the detonation of a high-explosive bomb shell or other explosion. A wave of high-pressure velocity (shock wave) is created and this is followed by one of negative decreased velocity, exerting a suction-like action. Blast causes pulmonary concussion and hemorrhage (lung blast / blast chest), laceration of other thoracic and abdominal viscera, ruptured ear drums, and minor effects in the central nervous system.
• white weapon injuries

Aetiology :
• accidental
• voluntary
Kinds :
• edged wound

Aetiology : instruments with a handle and a blade (bistoury, knives, scissors, paring-knife, dagger, razors, ...)
• abrasions
• linear wounds : straight or curved
• flap wound : triangular skin flap due to oblique action
• mutilating wound : complete detachment of protruding soft tissue(s)
• bite : a wound or puncture made by the teeth or other parts of the mouth
• morsus humanus : a bite by a human being
Aim & Localization :
• defense wounds : on hand palms
• passive defense wounds : on hand backs
• sidestep wounds : on shoulders and back
• suicide :
• wrist
• throat cutting

Pathogenesis : hemorrhage, gaseous embolism of neck vessels, and internal drowning
• ritual wounds
• eventration wounds
• bleeding woud
• disfigurement wound
Symptoms & signs : regular borders, acute corners, no loss of matter, short tails (on a flat surface : short and gross at entry, longer and subtle at exit as the blade enters pushing and exit sliding; on a curved surface : opposed or absent), the flaps of the wound fit together; hemorrhages, urging pain, retraction of borders, functional impotence according to areas involved
• pointed wound

Aetiology :
• subtle instruments : screwdrivers, punch, awl, ... => internal hemorrhagic stria for 1-2 days
• larger instruments : blind-end or perforatig wound whose diameter is lower than that of the instruments due to elastic skin retraction; excoriated halo and shape according to course of connective fibers.
Pathogenesis : as for single bullet firearms
Localization : precordial (single in suicide; multiple with defense wounds in homicide)
• edged and pointed wound

Symptoms & signs : oval-shaped wound with net borders and depth greater than length; borders are both acute with double edged arms ; short tails if oblique; sometimes contusion due to handle; separation between body layers with different elasticity is rare. The path is traight and fissurated, with subtle walls corresponding to the major axis of the arm (wounds involving viscera are sometimes more curved due to intrinsic peristalsis). Eventual exit wound is smaller and has no short tails.
Localization : precordial or epigastric (single in suicide; multiple with defense wounds in homicide : look at the direction of blood drops)
• cutting blow with a sword

Aetiology : heavy bodies
Pathogenesis : contemporaneous compression and contusion
Symptoms & signs : net borders and gross signs of contusion, poor hemorrhage due to hemostatic action of contusion, as for lacerated-contused wounds
• decapitation : the removal of the head, as of an animal, a fetus, or a bone; beheading
• decollation : decapitation, chiefly of a dead fetus
• dismemberment : amputation of a limb or a portion of it.
Localizations : head (homicide), anywhere (occupational injury), very rarely in suicides
• firearm injuries
• compressed air weapons
• magazine : the container of ammunitions inserted into the firearm
• cartdridge contains
• borrage to act as a shock-absorber but also to prevent gas leakages
• primer consists of :
• initiator (lead styphnate)
• oxidiser (barium nitrate)
• fuel (antimony sulfide)
• sensitizer (guanylnitrosoaminoguanyltetracene) is added to styphnate to make it more “irritable”
• frictionator (ground glass) helps in rupturing explosive crystals
• binders (gum arabic, gum tragacanth, starches, polyvinyl alcohol) are used to bind the material together
• coloring materials may be used to impart color
• explosives such as PETN, TNT and DDNP may also be used to provide heat and energy to the reaction.
• gunpowder : silver fulminate
• gun cotton : a general name for a series of explosive nitric ethers of cellulose, obtained by steeping cotton in nitric and sulphuric acids. Although there are formed substances containing nitric acid radicals, yet the results exactly resemble ordinary cotton in appearance. It burns without ash, with explosion if confined, but quietly and harmlessly if free and open, and in small quantity. Specifically, the lower nitrates of cellulose which are insoluble in ether and alcohol in distinction from the highest (pyroxylin) which is soluble. The gun cottons are used for blasting and somewhat in gunnery: for making celluloid when compounded with camphor; and the soluble variety (pyroxylin) for        making collodion. Gun cotton is frequenty but improperly called nitrocellulose. It is not a nitro compound, but an ester of nitric acid.
• ammunition or projectiles
• gun : a weapon which throws or propels a missile to a distance; any firearm or instrument for throwing projectiles, consisting of a tube or barrel closed at one end, in which the projectile is placed, with an explosive charge (such as guncotton or gunpowder) behind, which is ignited by various means. Guns are classified, according to their construction or manner of loading as rifled or smoothbore, breech-loading or muzzle-loading, cast or built-up guns; or according to their use, as field, mountain, prairie, seacoast, and siege guns. The longer the barrel, the highest the velocity of the gunshot.
• smaller guns (small arms) for hand use
• pistols : bifilar magazines may contain up to 15 munitions; the case is always expulsed
• revolver : may contain up to 12 (nowadays up to 6) munitions; in some kinds the cartdriges is not expulsed
• rifles
• carbines
• musket
• fowling pieces
• larger guns
• cannon : a large artillery gun that is usually on wheels
• ordnance : heavy weapons of warfare; cannon, or great guns, mortars, and howitzers; artillery; sometimes, a general term for all weapons and appliances used in war.
• fieldpieces
• carronades
• howitzers
• gun barrel : the barrel or tube of a gun
• long barrel firearms
• short barrel firearms
• gun carriage : the carriage on which a gun is mounted or moved
• sight
• aim devices
• cock or hammer
• percussion-cap
• machine gun : a breech-loading gun or a group of such guns, mounted on a carriage or other holder, and having a reservoir containing cartridges which are loaded into the gun or guns and fired in rapid succession. In earlier models, such as the Gatling gun, the cartridges were loaded by machinery operated by turning a crank. In modern versions the loading of cartidges is accomplished by levers operated by the recoil of the explosion driving the bullet, or by the pressure of gas within the barrel. Several hundred shots can be fired in a minute by such weapons, with accurate aim. The Gatling gun, Gardner gun, Hotchkiss gun, and Nordenfelt gun, named for their inventors, and the French mitrailleuse, are machine guns.
• dum-dum bullets have a second explosive charge whose primer is given by friction of body over cross-shaped notches on the curved nose of the bullet.
• lead-shot bullets don't need an exact aim and have a greater density/cost rate
• trigger
• some firearms have a safety "tooth" to keep hand below the cock and the carriage, preventing injuries during firing : otherwise injuries on the first interdigital space and the index finger of the gunman can be found, expecially when the firearm is unproperly handled (e.g. in suicides)
• plume : the gaseous formation that exits all openings of a firearm following the discharge of a round of ammunition
• K = m v² / 2. Stability of the trajectory depends on angular moment conservation and so on length of the barrel.
• low-velocity gunshots (800-900 m/s; police)
• high-velocity gunshots (1500-2000 m/s; military and urban wars)
• gunshot residue (GSR) / cartridge discharge residue (CDR) / firearm discharge residue (FDR) (smokes and dust) may cover the hand of the gunman and are lost with detersion. Though GSR could come from any of the 4 sources - primer, gunpowder, cartridge and ammunition - it is the primer which is a major contributor of GSR, and hence the importance of knowing its composition.
• one of the earliest efforts to answer this question scientifically was undertaken as early as 1933, when Teodoro Gonzalez of the Mexico City Police Laboratory developed the so called dermal nitrate or the paraffin test^ref. In this test Gonzalez attempted to establish the presence of nitro-compounds, instead of Pb, Sb or Ba as mentioned above. These nitro-compounds were supposed to come from the partially burnt and unburnt propellant particles. They “infected” the hands of the accused, as the “smoke” or the “plume” emanated from all openings of the gun just after shooting. He spread hot molten paraffin on the hands of the accused and made a kind of paraffin cast. This cast was then sprayed with a special chemical - a 0.25% solution of N,N’-diphenylbenzidine in concentrated sulphuric acid (this was later replaced with diphenylamine). If nitro-compounds were there on the cast, having come supposedly from the hands of the accused, the cast would turn deep blue. Of course this test did not determine whether the accused had handled the gun or not. It merely indicated that there were nitro-compounds on his hands, which could have come from shooting. However they could come from a number of naïve sources too - from nail polishes, fertilizers, various pharmaceuticals. Even a person who had contaminated his hands from his own urine (after urination), or who had just struck a match would give positive results.
• metals like lead (Pb), antimony (Sb) and barium (Ba) which are found in primers are also found in several other applications and there presence may be because of other reasons too. Lead for instance is used in as wide variety of things as lead batteries, solder, bearing metals, gasoline, paint, shielding sheet, matches and dyes. Similarly antimony is used in paint pigments, safety matches, brake pads and pyrotechnics, and barium is used in dyes, inks, photographic chemicals and insecticides. Finding of just one metal in GSR thus would not amount to anything. A GSR particle which contains all 3 metals, i.e. lead, antimony and barium must be considered as unique and almost certain indicator of a firing because these 3 metals are found together in just one instance - primers. Combinations of any 2 metals such as Pb-Sb, Pb-Ba, Sb-Ba etc should be characteristic, but not unique.
• Harrison and Gilroy test (1959) : swabs moistened with dilute hydrochloric acid, which were rubbed over the palms and backs of the hands of the accused, were then dried and treated with triphenylmethylarsonium iodide. They were dried again and then treated with sodium rhodizonate, and finally dilute hydrochloric acid was added. If antimony was present on the swabs, the first reagent (triphenylmethylarsonium iodide) would give a orange color, if lead or barium were present, the second reagent (sodium rhodizonate) would give a red color, and finally if just lead was present the addition of dilute hydrochloric acid would turn the spots purple. The big question that remained was of sensitivity.
• “color tests” were done away with, and were replaced with sophisticated modern analytical methods such as
• neutron activation analysis (NAA)
• atomic absorption spectroscopy (AAS)
• graphite furnace atomic absorption spectroscopy (GFAAS)
• flameless atomic absorption spectroscopy (FAAS)
• energy dispersive spectroscopy (EDS)
• inductively coupled plasma/atomic emission spectroscopy (ICP/AES)
• inductively coupled plasma/mass spectrometry (ICP/MS)
• photoluminescence technique
• anodic stripping voltammetry (ASV)
• differential pulse anodic stripping voltammetry (DPASV)
• proton induced X-ray emission (PIXE)
• X-ray microfluorescence
• histochemical techniques such as those using Alizarin Red S (ARS)
• scanning electron microscopy (SEM)
• computer controlled scanning electron microscopy (CCSEM)
Contrary to popular belief, hands are not the only places where GSR is deposited; it can get deposited over as different places as face, clothings, cars, even nostrils and ears of the subject and over inanimate objects such as tables, chairs, walls, drapes, floors, beds and a number of other items. Detection of GSR over these areas can indicate where exactly did the shooting take place. 2 most widely used methods to collect GSR are
• cotton swabs with 5% nitric acid are useful for atomic absorption, neutron activation analysis and inductively coupled plasma. Nitric acid could not possibly be used for SEM, because it immediately starts acting upon metallic particles, transforming their shape (one of the functions of SEM is to record the morphology of the GSR particles).
• adhesive stubs are useful for SEM
• multi-adhesive-layer stub, developed by Loren Sugarman in consultation with Dennis Ward
• single bullet munition injuries (longer than 45 mm) : calibre (most common 27, 38, and 75) is measured in mm in Europe and in in. in English-speaking countries; cartridge-case; bullets for war use require a protection to decrease lesivity.
• explosion zone : 0-200 m
• perforation zone : 300-500 m
• contusion zone > 500 m
Distance of firing : the entry hole is smaller than the calibre due to elastic retraction of tissues.
• exploded at contact : gases penetrate into skin and detach subcutis from cutis, then exit with high velocity due to elastic skin recoil, creating a stellate wound with up to 10 mm-long rays (absent in wound from bullets exploded with silenced firearms); the impact of the barrel (or the larger silencer) leads to an excoriated ecchymosis, grossly mimicking contused-lacerated wounds, but differential diagnosis is easily made looking for the exit hole or looking for the entry hole with a probe. In firearms with a spring-guiding rod, detached skin may be pressed against the backing firearm producing an ecchymosis just below the entry hole (Feltri's sign)
• exploded at near distance (< 40-45 cm) : also flames and gases (smokes and dusts), unless the firearm is silenced; intensity and diameter of halos decreases with distance and is greater from the side opposite to that from which the bullet came. Around the entry hole you can find :
• exploded < 5 cm : burn halo due to the flame (dry, yelllow skin with burning of the adnexa) surrounded by smoking halo (black skin due to deposition of smokes, removable by washing)
• exploded 10-15 cm : no longer burn halo, while smoking halo is due to deposition of both smokes and uncombusted smaller dust particles, surrounded by a tattoo due to penetration of larger dust particles into dermis (not washed away); compression halo : excoriated contusion due to high-pressure gases
• concentric if orthogonal entry
• eccentric if angulated entry
• exploded 30-35 cm : only excoriation and ecchymoses
• exploded at far distance (> 40-45 cm) : after 1 m all effects are due to the bullet alone. The detersion halo is a small blackish/oily circle due to deposition of barrel oil over the bullet (absent on modern firearms and often masked by hemorrhagic infiltrates; sometimes seen over clothes). The excoriation halo (2-3 mm-thick) is circular and larger on the side from which the bullet came.
After entry the bullet has a funnel-shaped path within body and can be deviated by bones.
Exit hole(s), more than one if the bullet fragmented : apart from bullets exploded at contact, the exit hole is usually larger and more irregular than the entry hole due to cutaneous extraflexion and has no excoriated halo (unless the deformed skin is pushed against a stiff surface, including heavy clothes), burn halo, tattoo or smoking halo (unless the bullet passed a body area with a limited thickness, e.g. a limb). These signs can be found over interposed materials instead of over skin, e.g. over clothes, hats or foulards (sometimes lost in aids), hairs (sometimes cut by surgeons), cushions, other limbs (e.g. head over neck)
Symptoms & signs :
• contusions : simple or excoriated ecchymoses whose appearance varies according to direction of the bullet during impact
• penetrating wounds : blind-end wounds, trapassing or perforating wounds, semichanneled or  wounds, contornating wounds, seton wound, ...
• explosion wounds : in empty viscera filled with fluids (e.g. stomach, bladder, ...), where energy propagates better
• secondary bullet wounds : due to fragmentation of the primary bullet before entry in the body
• multiple bullet munition injuries : exit hole is irregular due to modifications of the bullet across the body. Often whole bullets or fragments do not exit the body
• small bullets
• large bullets (each hole has a red halo due to compression over skin, as for single bullet injuries)
• exploded at contact : imprint of the barrel, irregular, stellate wound with festonated borders and blood infiltrates; burn, smoking and tattoo around the hole
• exploded at near distance : gases create suction of skin toward the barrel and the impact of the plastic container creates a crossed wound (from the opening of the container). When the distance is minimal the container may penetrate into the hole; ball effect within 1-2 m
• exploded at far distance : after 4 m, the wound image is no longer single and the plastic container falls down without leaving its imprint on the skin; after 8 m, rose-shaped distribution of ecchymoses due to bullets
Symptoms & signs : nerve section can mask pain. As bullets (aseptical per se) upon entry in body become covered with septical material they can cause peritonitis. Check if large blood vessels are along the trajectory.
• mechanical injuries leading to mechanical asphyxia
• ab externo obstruction of airways :
• suffocation / asphyxiation : the causing of or state of asphyxia
• direct suffocation : simultaneous occlusion of narices and mouth
• accidental
• homicide
• rarely suicide (psychiatric patients closing orifices with bandages)
• internal suffocation or obstruction : closure of respiratory tract by solid or semisolid foreign bodies
• mostly accidental
• infanticide
• homicide
• indirect suffocation : chest compression
• crowd asphyxia
• traumatic asphyxia
• burial asphyxia
• suspension asphyxia
• crucifixion asphyxia : stigmata
• choke / strangle : to interrupt respiration by latero-lateral or antero-posterior obstruction or compression of the neck with one of both hands

Aetiology :
• mostly homicide in subjects unable to face resistance (newborns, elderlies)
• accidental during sexual excitation, wrestling agonism or boys playing dangerous games
• suicide cannot be practiced by strangle
Pathogenesis : anomalous stimulation of baroceptors => hypervagotonia may lead to death within seconds, otherwise complete obstruction of trachea leads to asphyxia if maintained for 3-4'; complete simultaneous obstruction of both neck vessels rarely occurs
Symptoms & signs : necroptic findings : figurated excoriations produced by fingers or nails, subcutaneous and muscular hemorrhages in neck, lacerations of myofibers, fractures of thyroid and cricoid cartilages, and sometimes even hyoid bone with hematomas.
=> strangulation / choke : the condition resulting from interruption of respiration
• strangle : violent constriction exercitated by a lace around the neck placed under traction by a force other the body weight

Aetiology :
• homicide in infants, babies and surprised adults
• accidental (in workers managing rotating belts)
• rarely suicide
Pathogenesis : partial obstruction of trachea (the lace doesn't slide and doesn't press the base of the tongue against the soft palate), complete obstruction of common carotid arteries and jugular veins, and hypervagotonia leading to bradycardia and cardiac arrest
Symptoms & signs : necroptic findings : cord sign : in the mid of the neck with horizontal course and same deep along whole circumference. The sulcus is termed soft or hard according to the strenght of the lace which produced it
• hanging : violent constriction exercitated by a lace around the neck fixed at one end to a support and placed in traction by the weight of the body
• complete hanging (the patient is completely suspended)
• incomplete hanging (the patient can touch the land with the feet or other)
• typical hanging (if the knot is paced at the nape of the neck)
• interrupted hanging : if the lace breaks
• simulated shanging : if a cadaver is hanged
Aetiology :
• frequently suicide
• accidental (in boys playing dangerous games)
• rarely homicide (practiced only on surprised, psychopathic or conciousless erople or anyway unable to oppose resistance)
Pathogenesis : complete obstruction of trachea and carotid arteries and stirs the vagus nerve => cardiac arrest
Symptoms & signs :
• loss of consciousness is not always immediate and  are not constantly observed, on the contrary of the terminal respiratory movements and the final apnea. The heart continues to beat for 10-15 minutes after cessation of breath
• necroptic findings :
• external findings :
• cord sign : a cutaneous sulcus of different depth along its course (maximal at the midpoint) surrounded by an erythematous halo, excoirations, fine pointed hemorrhages and skin lifting in cristae correponding to turns of the lace. The sulcus is termed soft or hard according to the strenght of the lace which produced it
• cadaveric ecchymoses in distal regions of upper and lower limbs (ecchymoses above the level of the cord suggest simulated hanging)
• cyanosis in face (sometimes replaced by pallor)
• gravitary engorgement of external genitalia (not actual erection)
• internal findings :
• lacerations of myofibers and interstitial hemorrhages in neck muscles
• fractures of thyroid cartilage and hyoid bone
• transversal laceration of intima (Amussat's sign) of submucous layer (Friedberg's sign) of common carotid just before bifurcation
• ab interno obstruction of airways
• drowning : suffocation and death resulting from filling of the lungs with water or other substance or fluid, so that gas exchange becomes impossible.
• near drowning : survival for any length of time after submersion in water and temporary suffocation; it sometimes ends with secondary drowning.
• secondary drowning : delayed death from drowning, due to such complications as pulmonary alveolar inflammation
Aetiology :
• mostly accidental
• sometimes suicide (ligation of limbs or placement of weight linked to neck)
• rarely homicide, more common infanticide (immersion of infant in a recipient containing water or in a bath-tub)
• heritable and potentially lethal cardiac channelopathy, such as congenital long-QT syndrome or catecholaminergic polymorphic ventricular tachycardia^{ref1, ref2, ref3}. In fact, in a cohort of autopsy- negative, otherwise unexplained drowning victims, we found molecular evidence suggesting that in nearly 30% of swimming-related drownings, the victims may have had pathogenic mutations in genes associated with the long-QT syndrome and catecholaminergic polymorphic ventricular tachycardia^ref
Pathogenesis :
• sweet water (asphyxia lasts 3-5') : being hypotonic, from alveoli it migrates into blood leading to hypervolemia (up to 50% increase) => hemodilution, hypocalcemia, hyponatremia, hemolysis => anemia and hyperkalemia => ventricular fibrillation
• salt water : being hypertonic, plasma migrates into alveoli, causing massive acute pulmonary edema; hypovolemia leads to hemoconcentration; myocardial hypoxia leads to asystolia
Symptoms & signs :
• surprise stage : reflexed inspiration lasting a few seconds but deep enough to completely inflate lungs
• resistance stage : initial apnea (1') due to a reflex arising in upper airway mucosa once wet with fluid (water choke : laryngeal spasm caused by fluid entering the larynx and especially by getting between the true and false vocal cords)
• dyspnoic stage :
• apnoic stage :
• terminal stage :
Necroptic findings :
• external findings :
• cadaveric phenomena :
• cadaveric ecchymoses are pale red (as skin humidity facilitates diffusion of oxygen to cutaneous capillaries) and confluite in face, shoulders and anterior regions of chest as the cadaver is prone in water.
• cadaver cooling is accerelated due to high heat conductivity and lower temperature of water
• putrefaction is delayed as low temperature prevents microbial growth, but is faster once extracted from water
• maceration is due to water imbibition : skin whitening and lift in folds
• cornea and conjunctiva remain transparent and lucent as permanence in water prevented their dehydration
• sand, mould, algae, and larvae are common
• foamy or mucous fungus : a whitish or pink slaver around lips and narices after removal from water consisting of small iridescent air bubbles immersed in a mucous layer with high surface tension which preserve the fungal shape of the mass
• internal findings :
• foam in trachea and bronchi
• acute pulmonary emphysema due to dyspnoic stage (alveolar walls are lacerated due to hyperaeria and hyperhydria)
Laboratory examinations :
• microscopic lung examination
• research of particles in the drowning fluid (diatom : any unicellular microscopical form of alga having a wall of silica and belonging to the family Diatomaceae. Several species are toxic, causing the “red blooms” or “red tides.” The skeletal siliceous remains of many others are mined from deposits and used as filtering and abrasive agents)
• hemodilution test (cartometric, cryoscopic or electrical conductivity method)
• in drowning in sweet water : higher dilution in left ventricular blood than in right ventricular blood, and hence in pulmonary than in systemic blood
• in drowning in salt water : higher dilution in right ventricular blood than in left ventricular blood, and hence in systemic than in pulmonary blood
Complications in survivors : acute pulmonary edema, bronchopneumonia and sequelae of cerebral hypoxia
• internal drowning : inundation of airways by fluids coming from the inside of the body (blood, pus, exudates or trasudates)

Aetiology :
• traumatic (e.g. throat cutting) : cutting both neck blood vessels and airways causes blood to be aspirated into lungs
• spontaneous :
• aortic aneurysms opening into bronchus
• massive bronchorrhage during bronchopulmonary neoplasms
• abscesses opened into bronchus
• slow confination asphyxia : reclusion in a small volume environment where air recirculation is prevented.

Aetiology :
• mostly accidental (occupational injury : babies closed into trunks, cases, or armchairs; inhabitants blocked in collapsed houses; sailors blocked in sunken submarines; miners blocked in collapsed galleries; prisoners closed in railway carriages or in unsufficiently ventilated prisons)
• rarely homicide, common infanticide (into drawers, boxes, armchairs, ...), never suicide
Symptoms & signs : begin when P_O2 < 7% => death when P_O2 < 3%, also due to accumulation of CO₂.
Necroptic findings : attenuated findings, common acute pulmonary edema
Symptoms & signs : traumatism / traumatosis : the physical or psychic state resulting from an injury or wound; see also polytrauma
Therapy : traumatherapy / traumatotherapy : treatment of wounds and injuries.
• mechanical vibrations :
• oscillation : a backward and forward motion, like a pendulum
• sinusoidal
• periodical
• not periodical
• impulsive
• transient
• random
• vibration : a rapid movement to and fro
• frequency
• movement
• velocity
• acceleration
• intensity
Wisner classification :
• low-frequency vibrations : 0-2 Hz or cycles per second (cps)

Sources : cars, ships, airplanes, ...
Symptoms & signs (vestibular stimulation => motion sickness) which may be self-limiting at the end or after cessation of exposure or persist :
• sleepiness
• sweating
• pallor
• sialorrhea
• nausea and vomiting
Predisposing factors :
• constitutional habitus
• labirynthopathies
• cervical arthrosis
• visceral ptosis
• intermediate-frequency vibrations : 2-20 Hz =>

Sources : industrial machines or plants
• self-propelled and railway transport and lifting plants (cranes, ...)
• autonomous transport and lifting plants (cranes, ...)
• special transport and lifting plants (excavators, stevedores, ...)
• railways and heavy transport (tractors, trucks, bus, ...)
• fixed plants (olive-press, rolling millers, sieves, ...)
Symptoms & signs (vibration disease) :
• muscular hypertonia
• increased oxygen demand
• cardiac alterations : increased cardiac output
• pulmonary hyperventilation
• EEG modifications
• delayed patellar reflex
• reduced visual acuity
• raised auditory threshold
• endocrine alterations
• rachid alterations
• dyspepsia
• visceral ptosis
• pollakiuria, renal hematuria, nephrolithiasis and sometimes albuminuria
• genital apparatus alterations
• abortion
• genetic alterations ?
• headache
• vertigo
• anxiety
• high-frequency vibrations : > 20 Hz

Sources : vibrating instruments
• alternative percussory movement instruments, e.g. pneumatic drills, pickaxers, nail hammerers, vamp modelers, ...
• rotatory movement instruments, e.g. drills, perforators, milling machines, polishing machines, circular saws, ...
• mixed movement instruments, e.g. pneumatic drill, perforators, ...
Industrial applications :
• extraction industry (quarries, mines, tunnels, ...) : pneumatic and perforator drills, rotating perforators for excavation, demolition, and perforation
• siderurgic industry (foundries, laminators, ...) : presses, pneumatic drills and grinding-wheels for shaping, trimming and grinding, rough-hewing and finish of ingots, demolition and cleaning of furnaces
• metalmechanic industry : filing, planing, milling, grinding, and drilling machines for metal working, finish and polishing
• ship mechanic industry : chisels, grinding-wheels and milling machines for caulkering and welding auxiliary operations
• galvanic industry : milling, grinding, brushing and polishing machines for preparation and cleaning of metal surfaces
• ceramic, glass, bricks, and fire-bricks : milling and grinding machines for cleaning and rectification of finished products
• shoe-makers : grinding, sewing, and milling machines for assembling of vamps and bottom manufacturing
• binding industry : presses and vibrators for blowing and pressuring of concrete
• wood industry : saws, shearing and lapping machines for tree cutting down and preparation
• building industry : pneumatic hammer and drill, grinding wills and milling machines for housing, road building and maintenance
Instruments :
• large grinding machine : Riva-Calzoni Mod 5 SA/N 60 R ; 6.6 ; 6,000
• intermediate grinding machine : Riva-Calzoni Mod 5 SV/N 60 R ; 4.6 ; 6,000
• small grinding machine : Riva-Calzoni Mod 3 SV/N 120 R ; 2.0 ; 12,000
• drilling hammer : Boehler & Co Mod M 40 ; 4.5 ; 2,610
• angulated polishing machine : Thor-Fiap ; 4.3 ; 7,750
• decrusting machine : Ingersoll-Rand ; 0.94 ; 5,500
• polisher machine : Ingersoll-Rand ; 5.5 ; 9,000
• riveting machine : Consolidated Pneumatic Tool ; 7.3 ; 2,000
Factors affecting onset of syndromes :
• vibration characteristics
• vibrating instrument characteristics
• exposure characteristics
• biodynamic factors
• environmental factors
• individual factors
Symptoms & signs (vibrating instrument disease / segmental vibration syndrome) :
• hand-arm vibration syndrome : Raynaud's phenomenon (a.k.a. traumatic vasospastic disease (TVD) or vibration-induced white finger (VWF) in people who experience prolonged repetitive hand and arm high-frequency vibrations (e.g. work with carpenter's hammer or pneumatic drill), usually beginning in distal phalanges of ulnar fingers, and due to vascular, osteoarticular, neurological and tendineal lesions.
• vibration or pneumatic hammer disease : Raynaud's phenomenon with osteoarthritic changes and diminished flexion in joints of the arms and hands, seen in those who use vibrating tools for long periods
• Stockholm Workshop classification, 1986 :
• 0 : asymptomatic
• 1 (mild) : occasional pallor in extremity of at least 1 finger
• 2 (moderate) : occasional episodes of pallor in distal and intermediate phalanges in at least 1 finger
• 3 (severe) : frequent episodes of pallor in all phalanges of most fingers
• 4 (very severe) : as for stage 3, with associated cutaneous dystrophia at extremity of fingers
• Taylor-Pelmear vasculopathy staging :
• 0 : asymptomatic
• 0T/0N : paresthesia and/or torpor in at least 1 finger without interference in working and extra-working activities
• 1 : pallor in at least 1 finger without interference in working and extra-working activities
• 2 : pallor extended to more fingers with increased frequency of attacks, usually triggered by cold. Mild interference with working or extra-working activities
• 3 : pallor extended with frequent attacks during both summer and winter. Severe interference with working or extra-working activities
• 4 : involvement of all fingers with very frequent attacks. Need to change job.
• paraesthesias. Stockholm Workshop classification, 1986 :
• 0SN : no symptoms
• 1SN : intermittent torpor in fingers
• 2SN : intermittent or persistent torpor, reduced tactile, thermic, and pain sensitivity in fingers
• 3SN : intermittent or persistent torpor, reduced tactile discrimination and/or manual dexterity in fingers
• skeletal alterations in hand, wrists (radiocarpal, carpometacarpal arthrosis, scaphoid pseudoarthrosis (tarsal scaphoiditis / Kohler bone disease), semilunar osteonecrosis (Kienböck's disease), carpal bone pseudocysts), elbows (hyperstenosing osteoarthrosis (prevalence = 25-50%; pain at epicondylus and epitrochlea), dissecating osteoarthrosis, marginal osteophytosis with bone spurs), and shoulder (scapulohumeral arthrosis or arthritis, acromioclavicular arthrosis)
• lateral epicondilitis/epitrochleitis
• degenerative meniscopathies
• locked finger
• arthrosis
• rotator cuff
• scapulo-humeral periarthritis : changes of rhythm in scapulo/claviculo-humeral joints, humerus abduction
• radial styloiditis
• low back pain syndrome :
• idiopathic
• secondary to
• disk prolapse
• arthrosis of interapophysary facets
• osteoporosis
• occupational cervicobrachial disorder
• muscular cramps and pain; atrophy of interosseous muscles, tenar and hypotenar eminences
• carpal tunnel syndrome (CTS)
• Dupuytren's contracture
• CNS : syringomyelia, progressive muscular atrophy => muscular fatigue and asthenia
• PNS : decreased sensory and motor nerve conduction rate, ulnar nerve paralysis
• deafness
Laboratory examinations :
• cervical rachid, shoulder, elbow, and hand X-rays
• EMG and ENG
• photoplethysmography
• for differential diagnosis :
• CBC
• ESR
• fibrinogen
• glycemia
• lipid profile
• cryoglobulinemia
• cold agglutinins
• CRP
• mucoproteins
• rheumatoid factor
• protidogram
• uricemia
• anti-streptolysin O titer (ASOT)
Prevention :
• examination at engagement and periodical examinations
• medical and instrumental examinations for early diagnosis
• limitation to time of exposure with enlenghtned pauses to reduce consequences of vibrations
• definitive removal of workers from sources at onset of first symptoms or signs of vibration disease
• lifestyle changes : no tobacco smoke, ethanol, or hyperglycemia
• technical assistance of vibrating instruments
• use of individual protection devices (IPD), e.g. padded shock-absorbing gloves
Energy is transmitteed to human body through body supporting surfaces (varying according to upright or supine position) and the hand-upper limb system
Laboratory examinations :
• accelerometers (an instrument for measuring the acceleration (rate of change of velocity) of an object)
• amplificators
• transductors
• frequency analyzers

• temperature scales
• effective temperature index : an index indicating the warmth due to air temperature, air movement, and humidity
• standard temperature and pressure (STP) is defined as 0°C and 1 atmosphere of pressure.
• hyperthermia
• local hyperthermia
• inflammation
• systemic hyperthermia
• physical urticarias
Pathogenesis of heat syndrome : heat stress =>
• vasodilatation :
• heat loss
• circulatory and vasomotory unstability => heat edema => insufficient venous return => insufficient cerebral blood flow (CBF) => heat stroke
• sweating :
• cutaneous manifestations
• cramping
Symptoms & signs (caloric disease : any disease due to exposure to high temperature) :
• local hyperthermia
• first grade : pallor and edema
• second grade : clear flittena
• third grade : cyanosis and dermal necrosis
• fourth grade : serohematic flictena and deep necrosis
• erythema ab igne
• tropical immersion foot
• general hyperthermia :
• ventricular fibrillation
• stupor => hypothermic coma
• decreased metabolism
• heat exhaustion or prostration : an effect of excessive exposure to heat, occurring among workers in hot places such as furnace rooms and foundries and sometimes in those under prolonged exposure to the sun's heat. It is marked by subnormal temperature, with dizziness, headache, nausea, and sometimes delirium or collapse. Distinguished from heat stroke and insolation / sunstroke, in which the body temperature may be dangerously elevated
Therapy : actions for
• thermal load :
• warm : protection from heat
• external heat :
• room ventilation
• individual protection device (IPD)
• internal heat :
• cold :
• activation of heat sources
• adequate clothes
• physiological response :
• age
• weight (obese in cold environments and thin in hot ones)
• acclimatation (not properly ergonomics !)
• alimentary hygiene
Applications : thermoablative tumor therapy
Prevention : as architects use more and more glass in buildings, our offices are becoming greenhouses and air-conditioning bills are soaring. But conventional window tints are often unpopular because they block out both heat and light. At temperatures lower than 29°C, a new coating made from vanadium dioxide mixed with just 1.9% tungsten metal allows through both visible and infrared rays, just like normal glass, allowing all the Sun's heat to flood through when it is most needed. But once it heats up above 29°C, its atomic structure changes and it begins to reflect heat. This makes it more versatile than other coatings, which reflect heat all the time : it will take considerably less energy to keep a room cool. The chemists coated their windows by heating a sheet of glass to about 550°C. Then they made a steamy vapour of vanadium oxytrichloride and tungsten hexachloride, both common laboratory chemicals. As the molecules passed over the glass, they reacted together to form a thin film of vanadium dioxide that contained just a hint of tungsten. It is easy to vary the thickness of the film, but 100 nm is enough for the heat-busting layer to do its job^ref. Unlike many other coating methods, the process works at atmospheric pressure, which should make commercialization of the process much easier. The process is so flexible that they have been able to make the transition temperature go all the way down to 5°C, so it may be possible to make different glasses for different climates, each set to a different temperature. The only stumbling block is that the coating is coloured yellow. The team hope to add other chemicals to the film that will tone down the colour, perhaps to a misty grey, but there may be a niche market already waiting for their glass
Web resources :
• National Glass Association
• Pilkington Glass
Web resources : Extreme heat at CDC
• hypothermia

Risk factors :
• extreme ages
• newborns
• elderlies
• outdoor exposure
• job
• sport
• inadequate clothing
• drugs or other toxics
• ethanol
• phenothiazines
• barbiturates
• anaesthetics
• neuromuscular blockers
• others
• endocrine factors-related hypothermia
• hypoglycemia
• hypothyroidism
• adrenal failure
• hypopituitarism
• neurological factors-related hypothermia
• stroke
• hypothalamic alterations
• Parkinson's disease
• spinal cord injuries
• with multisystem involvement
• malnutrition
• sepsis
• shock
• burns and dermatological exfoliative conditions
• immobility and cachexia
Pathogenesis : reduced dissociation of O₂ from hemoglobin
Symptoms & signs :
• local hypothermia
• chilblain / chilblains / erythema pernio / pernio
• immersion foot
• trench foot
• trench hand
• frostbite / congelation : damage to tissues as the result of exposure to environmental temperatures < 0°C
• superficial frostbite : damage resulting from exposure to low temperatures, involving only the skin or extending to the tissue immediately beneath it; it may be manifested as simple erythema, transient anesthesia (grade I frostbite), and superficial bullae (grade II frostbite).
• deep frostbite : damage resulting from exposure to extremely low temperatures, involving not only the skin and subcutaneous tissue but also deeper tissues, with hemorrhagic bullae (grade III frostbite) and muscular and osseous lesion (grade IV frostbite) sometimes leading to gangrene and loss of affected parts; it is marked by persistent ischemia, secondary thrombosis, and livid cyanosis.
Risk factors : contact with thermoconductors (metals or volatile solutions), tight shoes or clothes, immobility, vasoconstrictor drugs
Pathogenesis : damage to endothelial cells => plasma extravasation => microvascular constriction => crystalization of extravascular fluid => intracellular dehydration => damaged tissues secrete TxA₂ and PGF_2a => platelet aggregation => leukocyte immobilization and vasoconstriction => microvascular thrombosis => arterovenous shunt => increased tissue pressure => edema => superficial thrombosis, ischemia and necrosis => mummification and demarcation within weeks
Laboratory examinations : thermography and techetium scintigraphy may help in evaluating perfusion a few days after heating
Therapy :

before thawing	during thawing	after thawing
remove from cold environment	evaluate eventual parenteral analgesia and administration of ketorolac	gently dry and protect the involved part; lift it; place tampons between toes if maceration occurred
prevent partial thawing and recongelation	administer oral ibuprofen at 400 mg	if clear fluid-filled vesicles are intact, fluid will be reabsorbed within days; if vesicles are broken, proceed to curettage and medications with antibiotics or aloe vera sterile unguent
stabilize central temperature and treat hypothermia	soak the part in running water at 37-40°C (with thermometric monitoring) containing antiseptical soap, until distal erythema occurs (10-45 minutes)	leave intact hemorrhagic vesicles to prevent infections
protect the congelated part, avoiding frictions or massages	ask the patient to move gently the part	follow therapy with ibuprofen (400 mg p.o., or 12 mg/kg /day) in administrations every 8-12 hours
look for eventual pathological conditions of medical or surgical interest	if pain is unresponsive to tratment, reduce temperature to 33-37°C	evaluate antitetanic and antistreptococcal prophylaxis; lift the part; hydrotherapy at 37°C

Complications : due to neuronal lesions and peristent anomalous sympathetic hypertone, with paresthesias, alterations of thermal perception and hyperhidrosis. Late findings are ungueal deformities, skin carcinomas and epiphyseal damages in babies
• systemic hypothermia (cryoplexy)
• climatic disease : any disease thought to be produced by a change of climate.

severity of hypothermia	body temperature	CNS	cardiovascular apparatus	respiratory apparatus	kidneys and endocrine apparatus	neuromuscular apparatus
mild	35°C - 32.2°C	linear cerebral metabolism depression; amnesia; apathy; dysarthria; alterations of judgement capacity; maladaptive behaviour	tachycrdia followed by progressive bradycardia; enlenghtnement of cardiac cycle; vasoconstriction; increased cardiac output and arterial pressure	tachypnea, then progressive decrease of respiratory volume/minute; decreased O2 consumption; bronchorrhea; bronchospasm	diuresis; increased catecholamines, adrenal streoids, triiodothyronine and thyroxine; increased metabolism at onset of chills	increased muscle tone preceding chills, then fatigue, chill-induced thermogenesis; ataxia
moderate	32.2°C-28°C	EEG alterations, progressive depression of LOC, midriasis, the patient paradoxically unclothes himself, hallucinations	progressive decrease of pulse and cardiac output; increased atrial and ventricular arrhythmias, aspecific EKG alterations (J wave), prolonged systole	hypoventilation; 50% decrease in CO2 production for each 8°C reduction in temperature; lack of airway protective reflexes; 50% reduced O2 consumption	50% increased renal blood flow; intact renal autoregulation; decreased insulin activity	hyporeflexia; decreased chill-induced thermogenesis, rigidity
severe	< 28°C	loss of ability of cerebrovascular autoregulation; decreased cerebral blood flow; coma; loss of ocular reflexes; progressive reduction of recorded EEG signal	progressive reduction of arterial pressure, heart rate and cardiac output; reentry dysrhytmias; decreased threshold of ventricular arrhythmias; asystolia	congestion and pulmonary edema; 75% decrease in O2 consumption; apnea	reduction of renal blood flow parallel to reduced cradiac output; extreme oliguria; poikilothermia; 80% reduction in basal metabolism	loss of movement; reduced nerve conduction velocity; peripheral areflexia

Web resources : Extreme cold at CDC

thermometer

• absolute humidity : the actual amount of vapor in the atmosphere expressed in weight per unit volume.
• relative humidity : the percentage of moisture in the air as compared to the amount necessary to cause saturation, which is taken as 100

hygrometer

• atmospheric electricity (lightnings attracted by metal objects weared by the patient) : 10⁶ V, 10⁵ A and 10³ J of heat. Lightning discharges flows in a 20-cm diameter channel and comes over land with a velocity varying between 30,000 and 100,000 km/s.
• artificial electricity
• domestic electricity (electric shock), including accidents in operating theatres
• electroexecution / electrocution : the taking of life (execution of capital death condamnations) by passage of electric current through the body
• torture
• electrotherapy

• electrolysis :
• Joule's effect : higher in high-resistance tissues => burns
• polarization of cell membrane potential => alteration of cytoplasmic electrolyte balance and deneaturation of high-molecular weight proteins => necrosis
• shape and location changes in tissues

• local injury :
• burns coming from endogenously generated heat by Joule effect => massive coagulation => mummification (painless, unsensitive eschar which doesn't undergo sepsis and repairs slowly but completely with smooth, elastin-rich, soft scars which doesn't leave functional impairments; different from carbonization due to complete combustion)
• voltaic arc burns : from sparks produced by electrical discharges between 5,000 and 50,000 V. Large burns affecting soft tissues and bones of limbs, head, and shoulders, consisting of wide carbonization areas, wide crateriform loss of substance and muscle roasting
• electrical conducer burns : from electrical discharges between 400 and 5,000 V
• electrical mark involving epidermis (containing heat alveoli joining into large bullae => sponge-like look), adnexa, and dermis (detachment, dermal papillae arrange into spheres, intravascular thrombosis due to electrothermal coagulation; metallization due to particles of the conducer penetrating into skin : the latter is the only element for certain differential diangosis with heat burns). They are resistant to putrefaction. They may lack when skin is wet : in individuals immersed in water the mark appears at the line of immersion. In babies marks are more common on lips or tongue due to accidental contact with domestic currents.
• type I : detachment of epidermis, no loss of matter, small skin rise with net borders, mildly depressed at center, white-gray colored and hard. Shape reflects that of the conducer
• type II : loss of matter, crateriform excavation with rise borders and exposed dermis; sometimes small dry, brown eschar with net borders and no surrounding inflammation
• systemic injury :
• 0.9-1.2 mA : paresthesia at entry point
• 5-25 mA : painful localized muscular contraction and cramps
• 25-80 mA : generalzied muscular tetanization (when respiratory muscles are paralyzed for a long time - as when the paralyzed hand remains attached to the electrical source - respiratory death may occuy)
• 80 mA - 3 A : when crossing the heart they cause ventricular fibrillation or other severe arrhythmias
• 3-8 A : depression of nervous system and paralysis cof bulbar centres => cardiorespiratory arrest
• lightnings (10⁵ A) :
• direct injuries : multiple localized burns with dry, excavated eschars, Liechtenberg's ligthning figures (superficial erythematous strie) => multivisceral congestion, subserosal pointed ecchymoses, cerebral and pulmonary edema, very severe burns, wide destructions and carbonization up to whole body incineration => immediate death. Rarely ligthning jokes (only hair burns, cloth burns or metal object fusion with no skin lesions) or death without external injuries.
• indirect injuries : due to air displacement, projection to field, traumas from objects thrown from explosion and fires provoked by the ligthning
Necroptic findings : abundant cadaveric ecchymoses due to low blood viscosity; intense and early rigor mortis if tetanization occurred, intense general congestion (expecially pulmonary and meningoencephalic); pointed subserosal and visceral hemorrhages if asphyxia occurred. Nervous (hemiparesis, peripheral neuritis with muscle atrophy, extrapyramidal syndromes and epilepsy), sensorial (hypoacusis and cataract), psychiatric (hallucinations, anxiety, mania or psychoneurosis) and cardiac (paroxysmal tachycardia, angina pectoris, bundle block, various arrhythmias, and myocardial infarction) sequelae may occur in survivors

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