Radium deposition in human brain tissue: A Geant4-DNA Monte Carlo toolkit study

NASA has encouraged studies on 226Ra deposition in the human brain to investigate the effects of exposure to alpha particles with high linear energy transfer, which could mimic some of the exposure astronauts face during space travel. However, this approach was criticized, noting that radium is a bone-seeker and accumulates in the skull, which means that the radiation dose from alpha particles emitted by 226Ra would be heavily concentrated in areas close to cranial bones rather than uniformly distributed throughout the brain. In the high background radiation areas of Ramsar, Iran, extremely high levels of 226Ra in soil contribute to a large proportion of the inhabitants' radiation exposure. A prospective study on Ramsar residents with a calcium-rich diet was conducted to improve the dose uniformity due to 226Ra throughout the cerebral and cerebellar parenchyma. The study found that exposure of the human brain to alpha particles did not significantly affect working memory but was significantly associated with increased reaction times. This finding is crucial because astronauts on deep space missions may face similar cognitive impairments due to exposure to high charge and energy particles. The current study was aimed to evaluate the validity of the terrestrial model using the Geant4 Monte Carlo toolkit to simulate the interactions of alpha particles and representative cosmic ray particles, acknowledging that these radiation types are only a subset of the complete space radiation environment.

Space Medicine: Why Do Recently Published Papers about Telomere Length Alterations Increase our Uncertainty Rather than Reduce it?

There is a growing interest in examining alterations in telomere length as a reliable biomarker of general health, as well as a marker for predicting later morbidity and mortality. Substantial evidence shows that telomere length is associated with aging; telomere shortening acts as a "counting mechanism" that drives replicative senescence by limiting the mitotic potential of normal (but not malignant) cells. In this Correspondence, we attempt to answer the question of why recently published papers about telomere length alterations increase our uncertainty rather than reduce it. This discussion includes three major research areas regarding telomere length: environmental stressors, aging, and life span. Our review suggests that activation of telomerase activity due to stressors in space might be a double-edged sword with both favorable and unfavorable consequences. The selection of an effect's consequence must clearly elucidate the experimental conditions as well as associated stressors. In this Correspondence, we attempt to answer the question of why recently published papers about telomere length alterations increase our uncertainty rather than reduce it. The selection of an effect's consequence must clearly elucidate the experimental conditions as well as associated stressors. Both positive and negative consequences must be clearly addressed in order to bolster the conclusions, as well as identify future research directions.

How Our Neanderthal Genes Affect the COVID-19 Mortality: Iran and Mongolia, Two Countries with the Same SARS-CoV-2 Mutation Cluster but Different Mortality Rates

Neanderthal genes possibly gave modern human protection against viruses. However, a recent study revealed that that a long sequence of DNA that is inherited from our Neanderthal ancestors can be linked to severe COVID-19 infection and hospitalization. Substantial evidence now indicates that our genetic background may be involved in the transmissibility of SARS-CoV-2 and the rapid progress of COVID-19 in some infected individuals. Although both morbidity and mortality of COVID-19 strongly depends on key factors such as age and co-existing health conditions, potential classes of human genomic variants possibly affect the likelihood of SARS-CoV-2 infection and its progress. Despite Iran and Mongolia seem to share the same SARS-CoV-2 mutation cluster, the COVID-19 mortality rates in these two countries are drastically different. While the population in Iran is 25.8 times higher than that of Mongolia, the number of confirmed cases is 1170 times higher. Moreover, the death rate shows a drastic difference. Since Neanderthals interbred with modern humans in Middle East between 47,000 and 65,000 years ago before going extinct 40,000 years ago, some Iranians have much more Neanderthal DNA than other people. Although neither genetic background nor environmental factors alone can determine our risk of developing severe COVID-19, our genes clearly affect both the development and progression of infectious diseases including COVID-19. Given these considerations, we believe that these great differences, at least to some extent, can be due to the proportion of Neanderthal genes among the people of these two countries

Blocking Short-Wavelength Component of the Visible Light Emitted by Smartphones' Screens Improves Human Sleep Quality

BACKGROUND

It has been shown that short-wavelength blue component of the visible light spectrum can alter the circadian rhythm and suppress the level of melatonin hormone. The short-wavelength light emitted by smartphones' screens can affect the sleep quality of the people who use these devices at night through suppression of melatonin.

OBJECTIVES

In this study, we examined the effects of covering the screens of smartphones with different filters (changing the effective wavelength of the light) on sleep delay time in 43 healthy students.

MATERIALS AND METHODS

Volunteer students were asked to go to bed at 23:00 and to use their mobile phones in bed for watching a natural life documentary movie for 60 minutes. No filter was used for one night while amber and blue filters were used for other 2 nights. Photospectrometry method was used to determine the output spectrum of the light passing through the filters used for covering the screens of the mobile phones. The order for utilizing amber or blue filters or using no filter was selected randomly. After 1 hour, the participants were asked to record their sleep delay time measured by a modified form of sleep time record sheet.

RESULTS

The mean sleep delay time for the "no-filter" night was 20.84±9.15 minutes, while the sleep delay times for the nights with amber and blue filters were 15.26±1.04 and 26.33±1.59 minutes, respectively.

CONCLUSION

The findings obtained in this study support this hypothesis that blue light possibly suppresses the secretion of melatonin more than the longer wavelengths of the visible light spectrum. Using amber filter in this study significantly improved the sleep quality. Altogether, these findings lead us to this conclusion that blocking the short-wavelength component of the light emitted by smartphones' screens improves human sleep.

Can Light Emitted from Smartphone Screens and Taking Selfies Cause Premature Aging and Wrinkles?

Since the early days of human life on the Earth, our skin has been exposed to different levels of light. Recently, due to inevitable consequences of modern life, humans are not exposed to adequate levels of natural light during the day but they are overexposed to relatively high levels of artificial light at night. Skin is a major target of oxidative stress and the link between aging and oxidative stress is well documented. Especially, extrinsic skin aging can be caused by oxidative stress. The widespread use of light emitting diodes (LEDs) and the rapidly increasing use of smartphones, tablets, laptops and desktop computers have led to a significant rise in the exposure of human eyes to short-wavelength visible light. Recent studies show that exposure of human skin cells to light emitted from electronic devices, even for exposures as short as 1 hour, may cause reactive oxygen species (ROS) generation, apoptosis, and necrosis. The biological effects of exposure to short-wavelength visible light in blue region in humans and other living organisms were among our research priorities at the Ionizing and Non-ionizing Radiation Protection Research Center (INIRPRC). Today, there is a growing concern over the safety of the light sources such as LEDs with peak emissions in the blue light range (400-490 nm). Recent studies aimed at investigating the effect of exposure to light emitted from electronic device on human skin cells, shows that even short exposures can increase the generation of reactive oxygen species. However, the biological effects of either long-term or repeated exposures are not fully known, yet. Furthermore, there are reports indicating that frequent exposure to visible light spectrum of the selfie flashes may cause skin damage and accelerated skin ageing. In this paper we have addressed the different aspects of potential effects of exposure to the light emitted from smartphones' digital screens as well as smartphones' photoflashes on premature aging of the human skin. Specifically, the effects of blue light on eyes and skin are discussed. Based on current knowledge, it can be suggested that changing the spectral output of LED-based smartphones' flashes can be introduced as an effective method to reduce the adverse health effects associated with exposure to blue light.

Does Exposure to Static Magnetic Fields Generated by Magnetic Resonance Imaging Scanners Raise Safety Problems for Personnel?

MRI workers are occupationally exposed to static and time-varying gradient magnetic fields. While the 24-hour time-averaged exposure to static magnetic fields is about a few mT, the maximum static field strength can be as high as 500 mT during patient setup. Over the past several years, our laboratory has performed extensive experiments on the health effects of exposure of animal models and humans to different sources of electromagnetic fields such as cellular phones, mobile base stations, mobile phone jammers, laptop computers, radars, dentistry cavitrons and MRI. This study is to investigate the adverse health effects in MRI workers and also to assess the effect of exposure of MRI workers to static magnetic fields on their cognitive functions. In the first phase of this study a questionnaire was designed to collect information from 120 MRI personnel. The collection of data about the adverse health effects was based on self-reporting by the participants. In the second phase, 47 volunteer university students were asked to continuously move around a 1.5 T MRI scanner. Visual reaction time and working memory tests were performed on all participants before and after the experiment. Forward digit span and backward digit span were used for assessing the working memory. Furthermore, participants were asked to report the symptoms they had experienced during the movement. The first phase of our study showed increased frequencies of adverse health effects in MRI workers. In this study the rates of self-reported symptoms such as a headache, sleep problems, myalgia, palpitation, fatigue, concentration problems, attention problems, nervousness and backpain were possibly affected by static magnetic field. Furthermore we found that reaction time and working memory could be influenced by the movements of the body around a MRI scanner. It can be concluded that movement through a high magnetic field can also lead to some adverse cognitive effects in MRI staff.

"Triple M" Effect: A Proposed Mechanism to Explain Increased Dental Amalgam Microleakage after Exposure to Radiofrequency Electromagnetic Radiation

A large body of evidence now indicates that the amount of mercury released from dental amalgam fillings can be significantly accelerated by exposure to radiofrequency electromagnetic fields (RF-EMFs) such as common mobile phones and magnetic resonance imaging (MRI). Studies performed on the increased microleakage of dental amalgam restorations after exposure to RF-EMFs have further supported these findings. Although the accelerated microleakage induced by RF-EMFs is clinically significant, the entire mechanisms of this phenomenon are not clearly understood. In this paper, we introduce "Triple M" effect, a new evidence-based theory which can explain the accelerated microleakage of dental amalgam fillings after exposure to different sources of electromagnetic radiation. Based on this theory, there are saliva-filled tiny spaces between amalgam and the tooth. Exposure of the oral cavity to RF-EMFs increases the energy of these small amounts of saliva. Due to the small mass of saliva in these tiny spaces, a small amount of energy will be required for heating. Moreover, reflection of the radiofrequency radiation on the inner walls of the tiny spaces causes interference which in turn produces some "hot spots" in these spaces. Finally, formation of gas bubbles in response to increased temperature and very rapid expansion of these bubbles will accelerate the microleakage of amalgam. Experiments that confirm the validity of this theory are discussed.

Cancers of the Brain and CNS: Global Patterns and Trends in Incidence

Miranda-Filho et al. in their recently published paper entitled "Cancers of the brain and CNS: global patterns and trends in incidence" provided a global status report of the geographic and temporal variations in the incidence of brain and CNS cancers in different countries across continents worldwide. While the authors confirm the role of genetic risk factors and ionizing radiation exposures, they claimed that no firm conclusion could be drawn about the role of exposure to non-ionizing radiation. The paper authored by Miranda-Filho et al. not only addresses a challenging issue, it can be considered as a good contribution in the field of brain and CNS cancers. However, our correspondence addresses a basic shortcoming of this paper about the role of electromagnetic fields and cancers and provides evidence showing that exposure to radiofrequency electromagnetic fields (RF-EMFs), at least at high levels and long durations, can increases the risk of cancer.

Comments on "Radiofrequency electromagnetic fields and some cancers of unknown etiology: An ecological study"

This correspondence refers to the Science of the Total Environment article by Gonzalez-Rubio et al. entitled "Radiofrequency electromagnetic fields and some cancers of unknown etiology: An ecological study". Authors of this paper have presented the findings of their preliminary epidemiological study which combined epidemiology, statistics and geographical information systems (GIS). Gonzalez-Rubio et al. have analyzed the possible link between exposure to Radiofrequency Electromagnetic Fields (RF-EMF) in the city of Albacete, Spain and the incidence of cancers such as lymphomas, and brain tumors. The shortcomings of this study are discussed.

Comments on "Association of excessive mobile phone use during pregnancy with birth weight: an adjunct study in Kumamoto of Japan Environment and Children's Study"

We have read with interest the article by Lu et al. entitled “Association of excessive mobile phone use during pregnancy with birth weight: an adjunct study in Kumamoto of Japan Environment and Children’s Study” published recently in the Environmental Health and Preventive Medicine. Although this paper addresses a very challenging issue, it has some shortcomings. Mortazavi et al. have previously studied the effects of ionizing and non-ionizing radiation on birth weight of newborns and found no statistical significant differences between the mean weight of newborns whose mothers had been exposed to electromagnetic fields (EMF) generated by mobile phones and those of non-exposed mothers. The study performed by Lu et al. cannot answer this very key question that whether ordinary use of mobile phone during pregnancy can lead to low birth weight. The origin of the controversy between the findings of these two studies and the shortcomings of the article by Lu et al. are discussed.

The Fundamental Reasons Why Laptop Computers should not be Used on Your Lap

As a tendency to use new technologies, gadgets such as laptop computers are becoming more popular among students, teachers, businessmen and office workers. Today laptops are a great tool for education and learning, work and personal multimedia. Millions of men, especially those in the reproductive age, are frequently using their laptop computers on the lap (thigh). Over the past several years, our lab has focused on the health effects of exposure to different sources of electromagnetic fields such as cellular phones, mobile base stations, mobile phone jammers, laptop computers, radars, dentistry cavitrons and Magnetic Resonance Imaging (MRI). Our own studies as well as the studies performed by other researchers indicate that using laptop computers on the lap adversely affects the male reproductive health. When it is placed on the lap, not only the heat from a laptop computer can warm men's scrotums, the electromagnetic fields generated by laptop's internal electronic circuits as well as the Wi-Fi Radiofrequency radiation hazards (in a Wi-Fi connected laptop) may decrease sperm quality. Furthermore, due to poor working posture, laptops should not be used on the lap for long hours.

Effect of 5% benzocaine gel on relieving pain caused by fixed orthodontic appliance activation. A double-blind randomized controlled trial

AIM

To compare the effectiveness of 5% benzocaine gel and placebo gel on reducing pain caused by fixed orthodontic appliance activation.

SETTING AND SAMPLE POPULATION

Thirty subjects (15-25 years) undergoing fixed orthodontics.

METHODS AND MATERIALS

A randomized, double-blind, placebo-controlled and cross-over clinical trial study was conducted. Subjects were asked to apply a placebo gel and 5% benzocaine gel, exchangeable in two consecutive appointments, twice a day for 3 days and mark their level of pain on a VAS scale. The pain severity was evaluated by means of Mann-Whitney U-test for comparing two gel groups, Kruskal-Wallis nonparametric test for overall differences and post hoc test of Dunnett for paired multiple comparisons. p-value was assigned <0.05.

RESULTS

The overall mean value of pain intensity for benzocaine and placebo gels was 0.89 and 1.15, respectively. The Mann-Whitney U-test indicated that there was no significant difference between overall pain in both groups (mean difference = 0.258 p ˂ 0.21). For both groups, pain intensity was significantly lower at 2, 6 and 24 h compared with pain experienced at days 2, 3 and 7.

CONCLUSION

Benzocaine gel caused a decrease in pain perception at 2 h compared with placebo gel. Peak pain intensity was at 2 h for placebo gel and at 6 h for benzocaine gel, followed by a decline in pain perception from that point to day 7 for both gels.

Short-Term Exposure to Electromagnetic Fields Generated by Mobile Phone Jammers Decreases the Fasting Blood Sugar in Adult Male Rats

BACKGROUND

Substantial evidence indicates that exposure to electromagnetic fields (EMF) above certain levels can affect human health through triggering some biological responses. According to WHO, short-term exposure to EMF at the levels present in the home/environment do not cause any apparent detrimental effects in healthy individuals. However, now, there is a debate on whether long-term exposure to low level EMF can evoke detrimental biological responses. Although based on the Communications Act of 1934, selling, advertising, using, or importing mobile jammers which block cell phone calls and text messages are illegal acts, in some countries these devices are being used for security purpose and for prevention of cheating during examinations.

METHODS

In this study 30 male Wistar rats were randomly divided into 3 groups of 10 each. The control group received no radiation. The sham exposure group was exposed to a switched-off jammer device. After fasting for 12 hours, the exposure group was exposed to EMFs at a distance of 50 cm from the jammer. Blood samples were collected from the tail vein after 24, 48 and72 hours and fasting blood sugar was measured by using a common blood glucose monitor (BIONIME GM110, Taiwan). The significance level was considered 5% and SPSS Ver. 21 was used for statistical analysis. The data were analyzed by ANOVA followed by Tukey's test.

RESULTS

A statistically significant difference was observed between blood sugar level in the control and exposure groups after 24, 48 and 72 hours of continuous irradiation (p values were <0.001, <0.001 and 0.002, respectively). No significant difference was found between the level of fasting blood sugar in control and sham groups.

CONCLUSION

Short-term exposure to electromagnetic field generated by mobile phone jammer can reduce blood sugar level in adult male rats. These findings, in contrast with our previous results, lead us to this conclusion that the use of these signal blocking devices in very specific circumstances may have some therapeutic effects. However, further studies have to be performed to find out the exact mechanism by which Jammer EMFs reduce fasting blood sugar.

Can the Accuracy of Home Blood Glucose Monitors be affected by the Received Signal Strength of 900 MHz GSM Mobile Phones?

BACKGROUND

People who use home blood glucose monitors may use their mobile phones in the close vicinity of medical devices. This study is aimed at investigating the effect of the signal strength of 900 MHz GSM mobile phones on the accuracy of home blood glucose monitors.

METHODS

Sixty non-diabetic volunteer individuals aged 21 - 28 years participated in this study. Blood samples were analyzed for glucose level by using a common blood glucose monitoring system. Each blood sample was analyzed twice, within ten minutes in presence and absence of electromagnetic fields generated by a common GSM mobile phone during ringing. Blood samples were divided into 3 groups of 20 samples each. Group 1: exposure to mobile phone radiation with weak signal strength. Group2: exposure to mobile phone radiation with strong signal strength. Group3: exposure to a switched-on mobile phone with no signal strength.

RESULTS

The magnitude of the changes in the first, second and third group between glucose levels of two measurements (׀ΔC׀) were 7.4±3.9 mg/dl, 10.2±4.5 mg/dl, 8.7±8.4 mg/dl respectively. The difference in the magnitude of the changes between the 1st and the 3rd groups was not statistically significant. Furthermore, the difference in the magnitude of the changes between the 2nd and the 3rd groups was not statistically significant.

CONCLUSION

Findings of this study showed that the signal strength of 900 MHz GSM mobile phones cannot play a significant role in changing the accuracy of home blood glucose monitors.

A Challenging Issue in the Etiology of Speech Problems: The Effect of Maternal Exposure to Electromagnetic Fields on Speech Problems in the Offspring

BACKGROUND

Nowadays, mothers are continuously exposed to different sources of electromagnetic fields before and even during pregnancy.  It has recently been shown that exposure to mobile phone radiation during pregnancy may lead to adverse effects on the brain development in offspring and cause hyperactivity. Researchers have shown that behavioral problems in laboratory animals which have a similar appearance to ADHD are caused by intrauterine exposure to mobile phones.

OBJECTIVE

The purpose of this study was to investigate whether the maternal exposure to different sources of electromagnetic fields affect on the rate and severity of speech problems in their offspring.

METHODS

In this study, mothers of 35 healthy 3-5 year old children (control group) and 77 children and diagnosed with speech problems who had been referred to a speech treatment center in Shiraz, Iran were interviewed. These mothers were asked whether they had exposure to different sources of electromagnetic fields such as mobile phones, mobile base stations, Wi-Fi, cordless phones, laptops and power lines.

RESULTS

We found a significant association between either the call time (P=0.002) or history of mobile phone use (months used) and speech problems in the offspring (P=0.003). However, other exposures had no effect on the occurrence of speech problems. To the best of our knowledge, this is the first study to investigate a possible association between maternal exposure to electromagnetic field and speech problems in the offspring. Although a major limitation in our study is the relatively small sample size, this study indicates that the maternal exposure to common sources of electromagnetic fields such as mobile phones can affect the occurrence of speech problems in the offspring.

Does Occupational Exposure of Shahid Dastghieb International Airport Workers to Radiofrequency Radiation Affect Their Short Term Memory and Reaction Time?

BACKGROUND

Airport workers are continuously exposed to different levels of radiofrequency microwave (RF/MW) radiation emitted by radar equipments. Radars are extensively used in military and aviation industries. Over the past several years, our lab has focused on the health effects of exposure to different sources of electromagnetic fields such as cellular phones, mobile base stations, mobile phone jammers, laptop computers, radars, dentistry cavitrons and MRI. The main goal of this study was to investigate if occupational exposure of Shahid Dastghieb international airport workers to radiofrequency radiation affects their short term memory and reaction time.

METHODS

Thirty two airport workers involved in duties at control and approach tower (21 males and 11 females), with the age range of 27-67 years old (mean age of 37.38), participated voluntary in this study. On the other hand, 29 workers (13 males, and 16 females) whose offices were in the city with no exposure history to radar systems were also participated in this study as the control group. The employees' reaction time and short term memory were analyzed using a standard visual reaction time (VRT) test software and the modified Wechsler memory scale test, respectively.

RESULTS

The mean± SD values for the reaction times of the airport employees (N=32) and the control group (N=29) were 0.45±0.12 sec and 0.46±0.17 sec, respectively.  Moreover, in the four subset tests; i.e. paired words, forward digit span, backward digit span and word recognition, the following points were obtained for the airport employees and the control group, respectively: (i) pair words test: 28.00±13.13 and 32.07±11.65, (ii) forward digit span: 8.38±1.40 and 9.03±1.32, (iii) backward digit span: 5.54±1.87 and 6.31±1.46, and (iv) word recognition: 5.73±2.36 and 6.50±1.93. These differences were not statistically significant.

CONCLUSION

The occupational exposure of the employees to the RF radiation in Shahid Dastghieb international airport does not have any significant detrimental effect on their reaction time as well as short term memory.

New Horizons in Enhancing the Proliferation and Differentiation of Neural Stem Cells Using Stimulatory Effects of the Short Time Exposure to Radiofrequency Radiation

Mobile phone use and wireless communication technology have grown explosively over the past decades. This rapid growth has caused widespread global concern about the potential detrimental effects of this technology on human health. Stem cells generate specialized cell types of the tissue in which they reside through normal differentiation pathways. Considering the undeniable importance of stem cells in modern medicine, numerous studies have been performed on the effects of ionizing and non-ionizing radiation on cellular processes such as: proliferation, differentiation, cell cycle and DNA repair processes. We have conducted extensive studies on beneficial (stimulatory) or detrimental biological effects of exposure to different sources of electromagnetic fields such as mobile phones, mobile phone base stations, mobile phone jammers, radar systems, magnetic resonance imaging (MRI) systems and dentistry cavitrons over the past years. In this article, recent studies on the biological effects of non-ionizing electromagnetic radiation in the range of radiofrequency (RF) on some important features of stem cells such as their proliferation and differentiation are reviewed. Studies reviewed in this paper indicate that the stimulatory or inhibitory effects of RF radiation on the proliferation and differentiation of stem cells depend on various factors such as the biological systems, experiment conditions, the frequency and intensity of RF and the duration of exposure.

Klebsiella pneumonia, a Microorganism that Approves the Non-linear Responses to Antibiotics and Window Theory after Exposure to Wi-Fi 2.4 GHz Electromagnetic Radiofrequency Radiation

BACKGROUND

Drug resistance is widely believed to be an increasingly serious threat to global public health. We have previously reported that short term exposure of microorganisms to diagnostic ultrasound waves could significantly alter their sensitivity to antibiotics. In our previous studies, Klebsiella pneumoniae showed major differences in the sensitivity to antibiotics in exposed and non-exposed samples. This study was aimed at investigating the alteration of antibiotic resistance of Klebsiella pneumonia, after exposure to Wi-Fi 2.4 GHz electromagnetic radiofrequency radiation.

MATERIALS AND METHODS

In this in vitro study, three replicate agar plates were used for each test. The antibiotic susceptibility test was carried out using disc diffusion method on Mueller Hinton agar plates and the inhibition zones in both control and exposed groups were measured. A common Wi-Fi router was used in this study as the radiofrequency exposure source. Irradiated samples were exposed to Wi-Fi radiofrequency radiation for 3, 4.5 and 8 hours.

RESULTS

Statistically significant variations of sensitivity to antibiotics were found for all studied antibiotics after 4.5 hours of RF exposure, compared to non-exposed bacteria. Interestingly, the mean diameters of the inhibition zones after 3 hours of exposure were less than those exposed for 4.5 hours. Following this rise in the sensitivity to antibiotics, a fall was observed in the bacteria exposed for 8 hours for all studied antibiotics.

CONCLUSION

The findings of this study show a statistically significant rise in the sensitivity of Klebsiella pneumoniae to different antibiotics after 4.5 hours of exposure to 2.4 GHz Wi-Fi radiation, followed by a fall after 8 hours of exposure. These observations can be interpreted by the concept of non-linearity in the responses of Klebsiella pneumoniae to different antibiotics after exposure to electromagnetic radiofrequency radiation. As in this study a minimum level of effect was needed for the induction of adaptive response, these results also confirm the validity of the so-called "window theory".

Does exposure to GSM 900 MHz mobile phone radiation affect short-term memory of elementary school students?

BACKGROUND

Now-a-days, children are exposed to mobile phone radiation at a very early age. We have previously shown that a large proportion of children in the city of Shiraz, Iran use mobile phones. Furthermore, we have indicated that the visual reaction time (VRT) of university students was significantly affected by a 10 min real/sham exposure to electromagnetic fields emitted by mobile phone. We found that these exposures decreased the reaction time which might lead to a better response to different hazards. We have also revealed that occupational exposures to radar radiations decreased the reaction time in radar workers. The purpose of this study was to investigate whether short-term exposure of elementary school students to radiofrequency (RF) radiation leads to changes in their reaction time and short-term memory.

MATERIALS AND METHODS

A total of 60 elementary school children ages ranging from 8 to 10 years studying at a public elementary school in Shiraz, Iran were enrolled in this study. Standardized computer-based tests of VRT and short-term memory (modified for children) were administered. The students were asked to perform some preliminary tests for orientation with the VRT test. After orientation, to reduce the random variation of measurements, each test was repeated ten times in both real and sham exposure phases. The time interval between the two subsequent sham and real exposure phases was 30 min.

RESULTS

The mean ± standard deviation reaction times after a 10 min talk period and after a 10 min sham exposure (switched off mobile) period were 249.0 ± 82.3 ms and 252.9 ± 68.2 ms (P = 0.629), respectively. On the other hand, the mean short-term memory scores after the talk and sham exposure periods were 1062.60 ± 305.39, and 1003.84 ± 339.68 (P = 0.030), respectively.

CONCLUSION

To the best of our knowledge, this is the first study to show that short-term exposure of elementary school students to RF radiation leads to the better performance of their short-term memory.

Production of a Novel Mineral-based Sun Lotion for Protecting the Skin from Biohazards of Electromagnetic Radiation in the UV Region

BACKGROUND

Sun protection materials have been one of the major concerns in pharmaceutical in-dustry since almost one century ago. Various materials have been found to have such an effect but there are still many unknown substances that have not been discovered. Objective : To introduce a novel mineral-based sun lotion with considerable UV absorption properties compared to commercially available sunscreens.

METHOD

 UV absorption properties of transparent plas-tic sheets covered by a uniform cream layer of different mineral-based sun lotions and a commercially available sun lotion were tested.

RESULTS

Sun lotions containing specific proportion of bentonite and zeolite minerals were capable of absorbing the highest level of UV light com-pared to that of the commercially available sun lotion.

CONCLUSION

Mineral-based sun lotions can be considered as cost effective alternatives for current commercial sunscreens.

Exposure to mobile phone radiation opens new horizons in Alzheimer's disease treatment

Alzheimer's disease, the most common type of dementia and a progressive neurodegenerative disease, occurs when the nerve cells in the brain die. Although there are medications that can help delay the development of Alzheimer's disease, there is currently no cure for this disease. Exposure to ionizing and non-ionizing radiation may cause adverse health effects such as cancer.  Looking at the other side of the coin, there are reports indicating stimulatory or beneficial effects after exposure to cell phone radiofrequency radiation. Mortazavi et al. have previously reported some beneficial cognitive effects such as decreased reaction time after human short-term exposure to cell phone radiation or occupational exposure to radar microwave radiation. On the other hand, some recent reports have indicated that RF radiation may have a role in protecting against cognitive impairment in Alzheimer's disease. Although the majority of these data come from animal studies that cannot be easily extrapolated to humans, it can be concluded that this memory enhancing approach may open new horizons in treatment of cognitive impairment in Alzheimer disease.