Oxidative stress response in SH-SY5Y cells exposed to short-term 1800 MHz radiofrequency radiation.

The exact mechanism that could explain the effects of radiofrequency (RF) radiation exposure at non-thermal level is still unknown. Increasing evidence suggests a possible involvement of reactive oxygen species (ROS) and development of oxidative stress. To test the proposed hypothesis, human neuroblastoma cells (SH-SY5Y) were exposed to 1800 MHz short-term RF exposure for 10, 30 and 60 minutes. Electric field strength within Gigahertz Transverse Electromagnetic cell (GTEM) was 30 V m-1 and specific absorption rate (SAR) was calculated to be 1.6 W kg-1. Cellular viability was measured by MTT assay and level of ROS was determined by fluorescent probe 2',7'-dichlorofluorescin diacetate. Concentrations of malondialdehyde and protein carbonyls were used to assess lipid and protein oxidative damage and antioxidant activity was evaluated by measuring concentrations of total glutathione (GSH). After radiation exposure, viability of irradiated cells remained within normal physiological values. Significantly higher ROS level was observed for every radiation exposure time. After 60 min of exposure, the applied radiation caused significant lipid and protein damage. The highest GSH concentration was detected after 10 minute-exposure. The results of our study showed enhanced susceptibility of SH-SY5Y cells for development of oxidative stress even after short-term RF exposure.

In vitro non-thermal oxidative stress response after 1800 MHz radiofrequency radiation.

In this study possible connection between radiofrequency exposure (RF) and development of oxidative stress was investigated by measuring impairment in cellular oxidation-reduction balance immediately after RF exposure. Fibroblast cells V79 were exposed for 10, 30 and 60 minutes to 1800 MHz RF radiation. Electric field strength was 30 V/m and specific absorption rate (SAR) was calculated to be 1.6 W/kg. Electromagnetic field was generated within Gigahertz Transversal Electromagnetic Mode cell (GTEM) equipped by signal generator, amplifier and modulator. Cell viability was determined by CCK-8 colorimetric assay and level of reactive oxygen species (ROS) was detected by dihydroethidium staining. Reduced glutathione (GSH) and glutathione peroxidase (GSH-Px) were used to assess cell antioxidant activity while lipid oxidative damage was evaluated measuring concentration of malondialdehyde. Viability of V79 cells remained within normal physiological values regardless of exposure time. Increased level of superoxide radicals was detected after 60-min exposure. Significantly higher GSH level was observed immediately after 10-min exposure with higher but insignificant activity of GSH-Px. Lipid oxidative damage in exposed cell samples was not observed. Short-term RF exposure revealed transient oxidation-reduction imbalance in fibroblast cells following adaptation to applied experimental conditions.

Cell oxidation-reduction imbalance after modulated radiofrequency radiation.

Aim of this study was to evaluate an influence of modulated radiofrequency field (RF) of 1800 MHz, strength of 30 V/m on oxidation-reduction processes within the cell. The assigned RF field was generated within Gigahertz Transversal Electromagnetic Mode cell equipped by signal generator, modulator, and amplifier. Cell line V79, was irradiated for 10, 30, and 60 min, specific absorption rate was calculated to be 1.6 W/kg. Cell metabolic activity and viability was determined by MTT assay. In order to define total protein content, colorimetric method was used. Concentration of oxidised proteins was evaluated by enzyme-linked immunosorbent assay. Reactive oxygen species (ROS) marked with fluorescent probe 2',7'-dichlorofluorescin diacetate were measured by means of plate reader device. In comparison with control cell samples, metabolic activity and total protein content in exposed cells did not differ significantly. Concentrations of carbonyl derivates, a product of protein oxidation, insignificantly but continuously increase with duration of exposure. In exposed samples, ROS level significantly (p < 0.05) increased after 10 min of exposure. Decrease in ROS level was observed after 30-min treatment indicating antioxidant defence mechanism activation. In conclusion, under the given laboratory conditions, modulated RF radiation might cause impairment in cell oxidation-reduction equilibrium within the growing cells.

Effect of electromagnetic radiofrequency radiation on the rats' brain, liver and kidney cells measured by comet assay.

The goal of study was to evaluate DNA damage in rat's renal, liver and brain cells after in vivo exposure to radiofrequency/microwave (Rf/Mw) radiation of cellular phone frequencies range. To determine DNA damage, a single cell gel electrophoresis/comet assay was used. Wistar rats (male, 12 week old, approximate body weight 350 g) (N = 9) were exposed to the carrier frequency of 915 MHz with Global System Mobile signal modulation (GSM), power density of 2.4 W/m2, whole body average specific absorption rate SAR of 0.6 W/kg. The animals were irradiated for one hour/day, seven days/week during two weeks period. The exposure set-up was Gigahertz Transversal Electromagnetic Mode Cell (GTEM--cell). Sham irradiated controls (N = 9) were apart of the study. The body temperature was measured before and after exposure. There were no differences in temperature in between control and treated animals. Comet assay parameters such as the tail length and tail intensity were evaluated. In comparison with tail length in controls (13.5 +/- 0.7 microm), the tail was slightly elongated in brain cells of irradiated animals (14.0 +/- 0.3 microm). The tail length obtained for liver (14.5 +/- 0.3 microm) and kidney (13.9 +/- 0.5 microm) homogenates notably differs in comparison with matched sham controls (13.6 +/- 0.3 microm) and (12.9 +/- 0.9 microm). Differences in tail intensity between control and exposed animals were not significant. The results of this study suggest that, under the experimental conditions applied, repeated 915 MHz irradiation could be a cause of DNA breaks in renal and liver cells, but not affect the cell genome at the higher extent compared to the basal damage.

Exposure to poultry dust and health effects in poultry workers: impact of mould and mite allergens.

PURPOSE: The aim of the study was to evaluate exposure to moulds and house dust mite Dermatophagoides pteronyssinus in poultry farms, and related health effects in poultry workers (PW). METHODS: The study involved 41 PW and 45 control office workers. Working environment was evaluated for D. pteronyssinus allergen (Der p 1), moulds and endotoxin. In workers, eye, skin and respiratory symptoms, ventilatory lung function, atopy markers (skin prick test to inhalatory allergens, total IgE) and specific IgG to moulds were assessed. RESULTS: Der p 1 levels ranged <0.1-3.3 microg/g, exposure to fungi was 4.9 x 10(3)-6.8 x 10(4) cfu/m(3), with prevailing Aspergillus, Penicillium and Mucor species, and endotoxin levels ranged 230-284 EU/m(3). In comparison to control subjects, significantly higher prevalence of work-related nose, asthma, eye and skin symptoms, and slight decline in ventilatory lung function was found in PW. PW had significantly higher prevalence of IgG antibodies to moulds comparing to controls (63 vs. 36%, respectively, P = 0.01), especially to Alternaria and Aspergillus species. The prevalence of atopy markers in PW was lower than in population-based studies. CONCLUSIONS: Hazardous levels of Der p 1, endotoxin and moulds were determined in poultry houses. High prevalence of work-related symptoms and IgG antibodies to moulds was found in PW. Healthy worker effect is proposed as an explanation of low atopy markers prevalence among PW.

Evaluation of basal DNA damage and oxidative stress in Wistar rat leukocytes after exposure to microwave radiation.

The aim of this study was to assess whether microwave-induced DNA damage is basal or it is also generated through reactive oxygen species (ROS) formation. After having irradiated Wistar rats with 915MHz microwave radiation, we assessed different DNA alterations in peripheral leukocytes using standard and formamidopyrimidine DNA-glycosylase (Fpg)-modified comet assay. The first is a sensitive tool for detecting primary DNA damage, and the second is much more specific for detecting oxidative damage. The animals were irradiated for 1h a day for 2 weeks at a field power density of 2.4W/m(2), and the whole-body average specific absorption rate (SAR) of 0.6W/kg. Both the standard and the Fpg-modified comet assay detected increased DNA damage in blood leukocytes of the exposed rats. The significant increase in Fpg-detected DNA damage in the exposed rats suggests that oxidative stress is likely to be responsible. DNA damage detected by the standard comet assay indicates that some other mechanisms may also be involved. In addition, both methods served proved sensitive enough to measure basal and oxidative DNA damage after long-term exposure to 915MHz microwave radiation in vivo.

[Issues related to long-term asbestos use and manufacture]. / Razmjeri problematike povezane s dugotrajnom preradom i uporabom azbesta.

Extensive measures to ban mining, manufacture, use, and trade of asbestos and asbestos materials have been taken worldwide. In this century asbestos will continue to be an economic, industrial, health, social, and environmental issue. Five thousand products that are still in use have been inherited from a century of asbestos processing. In 1999, the EU member states decided to take steps that would eventually terminate the use of asbestos. At the same time, about 4000 t of asbestos had been imported to Croatia every year. EU member states started to enforce asbestos ban in 2005. This encouraged the Croatian Ministry of Health and Social Welfare to issue a list of toxicants whose manufacture, trade, and use were banned, and which included asbestos and asbestos products. In 2007, several national acts came to force regulating protection of workers occupationally exposed to asbestos. Asbestos is ubiquitous in the environment. It has been released from construction materials during renovations, demolitions, maintenance, and other building activities. It is released by drilling, blowing, demolishing, loading, transport, and improper storage of asbestos materials. Asbestos was often used for insulation. It was favoured for its resistance to heat, fire, moisture, noise, electricity, friction, and fraying. Materials used for firefighting, insulation, protection from noise, and construction frequently contain one or more types of asbestos. Landfills present a particular problem, since asbestos materials can not be recognised macroscopically. Asbestos can be identified by standardised polarising microscopy. This raises the need for education, because human exposure should be kept as low as possible to prevent the development of asbestos-related diseases.

In vitro testing of cellular response to ultra high frequency electromagnetic field radiation.

The aim of this study was to evaluate whether low-level, ultra high frequency (UHF) irradiation of 935 MHz influences the cell structure and growth of V79 cells. UHF field was generated inside a Gigahertz Transversal Electromagnetic Mode cell (GTEM-cell) with a Hewlett-Packard signal generator. The electric field strength was 8.2+/-0.3 V/cm and the average specific absorption rate (SAR) was calculated to be 0.12 W/kg. Cell samples were cultivated in a humidified atmosphere at 37 degrees C with 5% CO2. Prepared cell samples were exposed to a 935 MHz continuous wave frequency field for 1, 2, and 3 h. The structure of microtubule proteins has been determined using the immunocytochemical method. Cell growth was determined by cell counts for each hour of exposure during five post-exposure days. Negative- and positive-cell controls were included into the experimental procedure. In comparison with control cells, the microtubule structure clearly altered after 3h of irradiation (p<0.05). Significantly decreased growth was noted in cells exposed for 3h three days after irradiation (p<0.05). It seems that the 935 MHz, low-level UHF radiation affects microtubule proteins, which consequently may obstruct cell growth.

Dose- and mode-dependent effect of halogen dental curing blue light on the V79-cell line.

The aim of this study was to evaluate the time and dose dependent effect of halogen light from dental curing unit on the cell viability, colony-forming ability and proliferation of the V79 cell culture. The investigation included the medium mode (M), exponential (E) and standard (S) illumination mode for 20, 40 and 80 seconds. The viability was determined using the trypan blue exclusion test. Colony forming ability was assessed by colony count on post-exposure day 7. Cell proliferation was determined by cell counts during five post-exposure days. The viability of cells was not affected by blue light in view of exposure time and modes. Colony forming ability in treated cells was slightly, but not significantly lower than in control cells. Cell proliferation was lower in cells exposed to the M mode for 80 s on post-exposure day 3 and 4 (p < 0.05). On the same post-exposure days, the proliferation of cells exposed to modes E and S, showed a significant inhibition after 20, 40 and 80 s of exposure (p < 0.05). Disrupted cellular functionality and no significant decrease in colony forming ability of V79 cells in addition to time- and dose dependent significant inhibition of cell proliferation might be ascribed to the photocuring blue light activity and/or changes in temperature during the course of experiment in vitro.

Impact of 864 MHz or 935 MHz radiofrequency microwave radiation on the basic growth parameters of V79 cell line.

The aim of this study was to evaluate and compare the influence of 864 MHz and 935 MHz radiofrequency/microwave (RF/MW) fields on the growth, colony-forming ability, and viability of V79 cells (continuous line). Cell samples with 1 x 10(4) V79 cells each, were exposed to continuous wave frequencies of 864 MHz and 935 MHz for 1, 2 and 3 hours. Exposed samples were matched with unexposed control samples. Specific absorption rate (SAR) was 0.08 W/kg for the 864 MHz or 0.12 W/kg for the 935 MHz field. Cell growth and viability were determined by counting cells every day for five days after exposure. Colony-forming ability was assessed by counting colonies seven days after exposure. The growth of the 864 MHz-irradiated cells was significant after two- and three-hour exposure 72 hours after irradiation (p < 0.05). The similar was observed 72 hours after exposure for cells exposed to 935 MHz microwaves for three hours (p <0.05). Colony-forming ability and cell viability in V79 cells exposed to 864 MHz or 935 MHz microwaves did not significantly differ from control cells. The two applied RF/MW fields showed similar effects on the growth, colony-forming ability and viability of V79 cells. Cell growth impact was time-dependent for both fields.

Erythropoietic dynamic equilibrium in rats maintained after microwave irradiation.

The aim of study was to define influence of radiofrequency microwave (RF/MW) radiation on erythropoiesis in rats. The kinetics of polychromatic erythrocytes (PCEs) and micronucleated (MN) PCEs in the bone marrow (BM) and peripheral blood (PB) of rats during the intermittent subchronic experiment was followed. Rats were exposed 2h/day, 7 days/week to RF/MW of 2.45 GHz and whole-body specific absorption rate (SAR) of 1.25+/-0.36 W/kg. Control animals were included in the study. Each exposed and control group was killed on the final day of irradiation. Acridine-orange stained BM and blood smears were examined by fluorescence microscope. PCEs were obtained by inspection of 2000 BM and 1000 PB erythrocytes/slides. BMMNs and PBMNs frequency was obtained by observation of 1000 PCEs/slides. BMPCEs were increased on day 8 and 15, and PBPCEs were elevated on days 2 and 8 (p<0.05). The BMMN frequency was increased on experimental day 15, and MNPCEs in the PB was increased on day 8 (p<0.05). Findings of BM and PBPCEs or MNPCEs declined nearly to the control values until the end of the experiment. Such findings are considered to be indicators of radiation effects on BM erythropoiesis consequently reflected in the PB. Rehabilitated dynamic haemopoietc equilibrium in rats by the end of experiment indicates possibility of activation adaptation process in rats to the selected experimental conditions of subchronic RF/MW exposure.

Comparison of 864 MHz and 935 MHz microwave radiation effects on cell culture.

The objective of this study was to compare the effects of 864 MHz and 935 MHz radiofrequency/microwave radiation on the ability of V79 cells to proliferate, form colonies and on their viability. For one, two and three hours, the cells were exposed to the 864 MHz field in a transversal electromagnetic mode cell (TEM) connected with amplifier and to the 935 MHz field in a gigahertz transversal electromagnetic mode cell (GTEM) equipped with a signal generator. The average specific absorption rate (SAR) was 0.08 W kg(-1) for the 864 MHz field and 0.12 W kg(-1) for the 935 MHz field. In comparison to the control cell samples, the growth curve of the 864 MHz irradiated cells showed a significant decrease after two-hour and three-hour exposure on the Day 3 after exposure. Likewise, cells exposed to 935 MHz microwaves for three hours showed a significant growth on Day 3 after exposure. The colony-forming ability and viability of cells exposed to 864 MHz and 935 MHz microwaves did not significantly differ from the matched controls. The applied RF/MW fields showed a similar effect on cell culture growth, colony-forming ability and viability of V79 cells.

Blood-forming system in rats after whole-body microwave exposure; reference to the lymphocytes.

The influence of 2.45 GHz microwave (RF/MW) irradiation on blood-forming cells after whole-body irradiation of rats was investigated. The exposures were conducted with a field power density of 5-10 mW/cm2, and whole-body average specific absorption rate (SAR) of 1-2 W/kg. Four experimental subgroups were created and irradiated 2, 8, 15 or 30 days, for 2 h a day, 7 days a week. Concurrent sham-exposed rats were also included in the study. The cell response was assessed by number and type of the bone marrow nuclear cells and peripheral blood white cells using standard laboratory methods. Significant decrease in lymphoblast count was obtained at 15 and 30th experimental day (P < 0.05), whereas other examined parameters did not significantly differed in comparison to the sham-exposed controls. The findings point out at stress response in blood-forming system in rats after selected microwave exposure, which could be considered rather as sign of adaptation than malfunction.

Micronucleus induction after whole-body microwave irradiation of rats.

Adult male Wistar rats were exposed for 2 h a day, 7 days a week for up to 30 days to continuous 2,450 MHz radiofrequency microwave (rf/MW) radiation at a power density of 5-10 mW/cm(2). Sham-exposed rats were used as controls. After ether anesthesia, experimental animals were euthanized on the final irradiation day for each treated group. Peripheral blood smears were examined for the extent of genotoxicity, as indicated by the presence of micronuclei in polychromatic erythrocytes (PCEs). The results for the time-course of PCEs indicated significant differences (P<0.05) for the 2nd, the 8th and the 15th day between control and treated subgroups of animals. Increased influx of immature erythrocytes into the peripheral circulation at the beginning of the experiment revealed that the proliferation and maturation of nucleated erythropoietic cells were affected by exposure to the 2,450 MHz radiofrequency radiation. Such findings are indicators of radiation effects on bone-marrow erythropoiesis and their subsequent effects in circulating red cells. The incidence of micronuclei/1,000 PCEs in peripheral blood was significantly increased (P<0.05) in the subgroup exposed to rf/MW radiation after eight irradiation treatments of 2 h each in comparison with the sham-exposed control group. It is likely that an adaptive mechanism, both in erythrocytopoiesis and genotoxicity appeared in the rat experimental model during the subchronic irradiation treatment.

Erythropoietic changes in rats after 2.45 GJz nonthermal irradiation.

The purpose of this study was to observe the erythropoietic changes in rats subchronically exposed to radiofrequency microwave (RF/MW) irradiation at nonthermal level. Adult male Wistar rats (N=40) were exposed to 2.45 GHz continuous RF/MW fields for 2 hours daily, 7 days a week, at 5-10 mW/cm2. Exposed animals were divided into four subgroups (n=10 animals in each subgroup) in order to be irradiated for 2, 8, 15 and 30 days. Animals were sacrified on the final irradiation day of each treated subgroup. Unexposed rats were used as control (N=24). Six animals were included into the each control subgroup. Bone marrow smears were examined to determine absolute counts of anuclear cells and erythropoietic precursor cells. The absolute erythrocyte count, haemoglobin and haematocrit values were observed in the peripheral blood by an automatic cell counter. The bone marrow cytogenetic analysis was accomplished by micronucleus (MN) tests. In the exposed animals erythrocyte count, haemoglobin and haematocrit were increased in peripheral blood on irradiation days 8 and 15. Concurrently, anuclear cells and erythropoietic precursor cells were significantly decreased (p < 0.05) in the bone marrow on day 15, but micronucleated cells' frequency was increased. In the applied experimental condition, RF/MW radiation might cause disturbance in red cell maturation and proliferation, and induce micronucleus formation in erythropoietic cells.

Asbestosis in the Republic of Croatia.

Croatians have been exposed to asbestos in the shipbuilding and asbestos-cement industries since 1945. The first cases of asbestosis were reported in 1961; 317 cases were recorded from 1990 to 2000. The Croatian Cancer Registry recorded 248 malignant pleural mesotheliomas between 1991 and 1997, two thirds of which were attributable to occupational exposures to asbestos. The Croatian Asbestosis Patient Association was founded in 1998 to help victims. Croatian law defines the employer's responsibility for work-related health damage and compensation, but average legal proceedings for asbestosis claims take about seven years. Croatian law does not ban the manufacture and import of asbestos. Croatia as a transitional country is subject to socioeconomic pressures. Future approaches to the asbestos issue will depend on revised regulations, which are expected to conform to recommendations of the European Union by 2005.

Histological and cytological examination of rat reproductive tissue after short-time intermittent radiofrequency exposure.

The unfavourable outcomes of mobile phone use on male fertility have still not been fully elaborated. To establish the potentially adverse effects of everyday exposure to radiofrequency radiation (RF) on humans, we performed a controlled animal study that aimed to investigate the influence of RF radiation on rat testis histology as well as the amount, mobility, and structure of epididymal free sperm cell population. Eighteen adult male rats were divided into two groups of nine. One group comprised sham-exposed control animals, while the other group endured total body irradiation for an hour daily during two weeks. A 915 MHz RF field, power density of 2.4 W m(-2) and strength of 30 V m(-1) was generated in a Gigahertz Transversal Electromagnetic chamber. The specific absorption rate (SAR) was 0.6 W kg(-1). Body mass and temperature were measured before and after each exposure treatment. Immediately after the last exposure, the animals were sacrificed and testes removed and prepared for histological analysis. The free sperm cells were collected from the cauda epididymis and their quantity, quality, and morphology were microscopically determined using a haemocytometer. No statistically significant alteration in any of the endpoints was observed. This study found no evidence of an unfavourable effect of the applied RF radiation on testicular function or structure. Based on these results, we can conclude that short-time intermittent exposure to RF radiation does not represent a significant risk factor for rat reproductive functions.

Biological indicators in response to radiofrequency/microwave exposure.

Over the years, due to rapid technological progress, radiation from man-made sources exceeded that of natural origin. There is a general concern regarding a growing number of appliances that use radiofrequency/ microwave (RF/MW) radiation with particular emphasis on mobile communication systems. Since nonthermal biological effects and mechanisms of RF/MW radiation are still uncertain, laboratory studies on animal models, tissues, cells, and cell free system are of extraordinary importance in bioelectromagnetic research. We believe that such investigations play a supporting role in public risk assessment. Cellular systems with the potential for a clear response to RF/MW exposures should be used in those studies. It is known that organism is a complex electrochemical system where processes of oxidation and reduction regularly occur. One of the plausible mechanisms is connected with generation of reactive oxygen species (ROS). Depending on concentration, ROS can have both beneficial and deleterious effects. Positive effects are connected with cell signalling, defence against infectious agents, and proliferative cell ability. On the other hand, excessive production, which overloads antioxidant defence mechanism, leads to cellular damage with serious potential for disease development. ROS concentration increase within the cell caused by RF/MW radiation seems to be a biologically relevant hypothesis to give clear insight into the RF/MW action at non-thermal level of radiation. In order to better understand the exact mechanism of action and its consequences, further research is needed in the field. We would like to present current knowledge on possible biological mechanisms of RF/MW actions.

Non-thermal biomarkers of exposure to radiofrequency/microwave radiation.

This article gives a review or several hypotheses on the biological effects of non-thermal radiofrequency/microwave (RF/MW) radiation and discusses our own findings from animal and in vitro studies performed over the last decade. We have found that RF/MW radiation disturbs cell proliferation and leads to cell differentiation in the bone marrow, which is reflected in the peripheral blood of rats. Repeated RF/MW radiation can also temporarily disrupt melatonin turnover. The observed changes seem to be a sign of adaptation to stress caused by irradiation rather than of malfunction. The article looks further into the basic mechanisms of RF/MW biological action, including cell growth parameters, colony-forming ability, viability, and the polar and apolar protein cytoskeleton structures. The observed reversible cell changes significantly obstructed cell growth. In contrast to the apolar intermediate proteins, the intracellular polar microtubule and actin fibres were damaged by radiation in a time-dependent manner. These significantly altered parameters can be considered as the biomarkers of exposure. Future research should combine dosimetry, experimental studies, and epidemiological data.

The effects of bluephase LED light on fibroblasts.

OBJECTIVE: The aim of this study was to evaluate the effect of Bluephase light emitting diode (LED) light on cell viability, colony-forming ability and proliferation in V79 cell culture and to determine how much the temperature of the nutrient medium rose. METHODS: The investigation included a low (L), soft start (S) and high (H) illumination mode for 20, 40 and 80 seconds. The viability was determined by the trypan blue exclusion test, colony-forming ability by counting colonies 7 days after exposure and cell proliferation by the cell counts on 5 post-exposure days. The temperature change during illumination was recorded (0.1°C sensitivity). RESULTS: In each experimental condition, 90-95% of the cells were viable, which was in the same range as the controls. Colony-forming ability was not found to be significantly lower (P<.05). A significant decrease in proliferation was recorded on the 4th post-exposure day with S and H irrespective of time, on the 3(rd) day with S for 80 s and H for 40 and 80 s, and with S and H for 80 s on the 2(nd) day (P<.05).The temperature rise was significant with S (P<.05) and H (P<.05), irrespective of exposure duration. CONCLUSION: Dependent on total energy density, LED blue light affects the mitotic activity of cells in its path to a certain extent. Altered mitotic activity was not noted with illumination at the low power mode (intensity of 421.7 ±1.1 mW/cm(2)). The greatest temperature rise was 8.3 °C and occurred at the highest intensity and exposure duration.