SMJ Mortazavi

Solar particle events (SPEs) are primarily composed of low to moderate energy protons while isotropic galactic cosmic radiation is dominated by protons with a wider energy range. To date, different methods for physical shielding of spacecrafts as well as increasing biological radioresistance using radioprotectors or even adaptive response-induced radioresistance after exposure to low level chronic space radiation have been proposed to solve the problem of intense radiation in the space… نمایش موارد بیشتر

Solar particle events (SPEs) are primarily composed of low to moderate energy protons while isotropic galactic cosmic radiation is dominated by protons with a wider energy range. To date, different methods for physical shielding of spacecrafts as well as increasing biological radioresistance using radioprotectors or even adaptive response-induced radioresistance after exposure to low level chronic space radiation have been proposed to solve the problem of intense radiation in the space environment. Limitations of physical shielding such as extremely high cost of transporting heavy structures into space and their incapability to provide adequate shielding against heavy ions at an appropriate thickness, prompt us to explore biological methods for increasing radioresistance during space missions. Mortazavi et al have previously reported that screening of the candidates of long-term space missions by conducting Ground-based in vitro adaptive response studies before any mission identifies the individuals who respond well to low levels of ionizing radiation and reveal high magnitudes of radioadaptive response. They have also found that laboratory animals pre-irradiated with radiofrequency radiation were less susceptible to subsequent lethal effects of high doses of ionizing radiation Furthermore, Mortazavi et al have recently showed that based on their findings in an animal model, radiofrequency-induced adaptive response can be used as a method for decreasing the risk of infection during deep space missions. These biological methods for management of radiation risk in manned deep space missions will be challenging issues in future space exploration. نمایش موارد کمتر

As a member of the United Nations Committee on the Peaceful Uses of Outer Space (COPUOS), Iran has a long-term space exploration program. Space radiation is one of the challenges facing humans when they go outside Earth's protective atmosphere and magnetic field. Space is an environment that the cardinal principles of radiation protection; i.e. time, distance and shielding cannot be effectively applied. On the other hand, well-known limitations of physical shielding prompt us to explore… نمایش موارد بیشتر

As a member of the United Nations Committee on the Peaceful Uses of Outer Space (COPUOS), Iran has a long-term space exploration program. Space radiation is one of the challenges facing humans when they go outside Earth's protective atmosphere and magnetic field. Space is an environment that the cardinal principles of radiation protection; i.e. time, distance and shielding cannot be effectively applied. On the other hand, well-known limitations of physical shielding prompt us to explore biological methods for inducing radioresistance during space missions. Screening of the candidates of long-term space missions by ground-based in vitro adaptive response studies might be helpful. It has recently been shown that the detrimental effects of exposure to protons and HZE particles can be prevented by some dietary supplements. Interestingly, in contrast with radioprotectors, these dietary supplements can prevent radiation induced detrimental effects even when applied several days after exposure to radiation. It seems that finding appropriate radiation mitigators with a post-exposure time window in excess of 24 hours will be a critical goal in planning future manned space missions. In this paper, the advantages of biological shielding over current well defined physical shielding will be discussed. نمایش موارد کمتر

The aim of this study was to investigate the effect of pre-irradiation with microwaves on the induction of radioadaptive response. In the 1st phase of the study, 110 male mice were divided into 8 groups. The animals in these groups were exposed/sham-exposed to microwave, low dose rate gamma or both for 5 days. On day six, the animals were exposed to a lethal dose (LD). In the 2nd phase, 30 male rats were divided into 2 groups of 15 animals. The 1st group received microwave exposure. The 2nd… نمایش موارد بیشتر

The aim of this study was to investigate the effect of pre-irradiation with microwaves on the induction of radioadaptive response. In the 1st phase of the study, 110 male mice were divided into 8 groups. The animals in these groups were exposed/sham-exposed to microwave, low dose rate gamma or both for 5 days. On day six, the animals were exposed to a lethal dose (LD). In the 2nd phase, 30 male rats were divided into 2 groups of 15 animals. The 1st group received microwave exposure. The 2nd group (controls) received the same LD but there was no treatment before the LD. On day 5, all animals were whole-body irradiated with the LD. Statistically significant differences between the survival rate of the mice only exposed to lethal dose of gamma radiation before irradiation with a lethal dose of gamma radiation with those of the animals pre-exposed to either microwave (p=0.02), low dose rate gamma (p=0.001) or both of these physical adapting doses (p=0.003) were observed. Likewise, a statistically significant difference between survival rates of the rats in control and test groups was observed. Altogether, these experiments showed that exposure to microwave radiation may induce a significant survival adaptive response. نمایش موارد کمتر

Some Areas of Ramsar, a city in northern Iran are among the world’s well-known inhabited areas with highest levels of natural radiation. Annual exposure levels in these areas are up to 260 mGy y‐1 and the mean exposure rate is about 10 mGy y‐1 for a population of about 2000 residents. If elevated levels of natural radiation as high as a few hundred mSv per year is detrimental to health and leads to higher risks of genetic abnormalities and cancer, it should be evident in the residents of areas… نمایش موارد بیشتر

Some Areas of Ramsar, a city in northern Iran are among the world’s well-known inhabited areas with highest levels of natural radiation. Annual exposure levels in these areas are up to 260 mGy y‐1 and the mean exposure rate is about 10 mGy y‐1 for a population of about 2000 residents. If elevated levels of natural radiation as high as a few hundred mSv per year is detrimental to health and leads to higher risks of genetic abnormalities and cancer, it should be evident in the residents of areas such as Ramsar. However, it has been reported that no detrimental biological effects have ever been detected in high natural background radiation areas. Some studies indicate that Ramsar residents not only show a significant increase in DNA repair but also demonstrate induction of radioadaptive response. There is currently a great debate over the shape of the dose‐response curve for stochastic effects such as mutations and cancer after exposure to low doses of ionizing radiation. Linear‐no‐threshold (LNT) model predicts that every dose, no matter how low, carries some cancer risk. Lack of any proven detrimental effect in the residents of high natural background radiation areas of Ramsar may be due to the induction of nonlinear dose‐response relationships which are not compatible with the widely accepted LNT hypothesis. نمایش موارد کمتر

Energetic solar particle events (SPE) which are among the main sources of ionizing radiation can be life threatening to astronauts who are not adequately protected. To date, physical shielding of spacecrafts and inducing radioresistance by using radioprotectors have been proposed by different investigators. Mortazavi et al. have previously reported that screening of the candidates of long-term space missions by conducting Ground-based in vitro adaptive response studies before any mission… نمایش موارد بیشتر

Energetic solar particle events (SPE) which are among the main sources of ionizing radiation can be life threatening to astronauts who are not adequately protected. To date, physical shielding of spacecrafts and inducing radioresistance by using radioprotectors have been proposed by different investigators. Mortazavi et al. have previously reported that screening of the candidates of long-term space missions by conducting Ground-based in vitro adaptive response studies before any mission identifies the individuals who respond well to low levels of ionizing radiation and reveal high magnitudes of radioadaptive response. On the other hand, Mortazavi et al. have recently showed that radiofrequency-induced adaptive response can be used as a method for decreasing the risk of infection caused by immunosuppression during deep space missions. Furthermore, over the past years the radioresistance induced by a wide variety of radioprotectors has been studied. According to classical radiobiology, chemical radioprotective agents must be administered before irradiation or at the time of irradiation, to increase the mean survival rate of the exposed individuals. A revolution in this paradigm was started in 2010, when investigators reported that a diet supplemented with antioxidants administered starting 24 h after total-body irradiation is more effective than if given soon after the exposure (radiation mitigation). This finding along with the above mentioned interventions open new horizons in inducing biological radioresistance against unpredictable high levels of radiation due to solar particle events. This wide time window indeed enables astronauts to firstly evaluate their radiation doses before making any decision on the type of intervention. As major solar particle events last for hours, astronauts will be able to consult distinguished radiation biologists via satellite telecommunication before choosing any medical intervention. نمایش موارد کمتر

Abstract Background: Radar transmitters emit high-power radiofrequency radiation by creation of a high-voltage and high-frequency alternating electrical current. Methods: Health effects of occupational exposure to military radar were investigated. Visual reaction time was recorded with a simple blind computer-assisted-visual reaction time test. To assess the short-term memory, modified Wechsler Memory Scale test was performed. Results: The mean +/- SD reaction time in radar works (N=100) and… نمایش موارد بیشتر

Abstract Background: Radar transmitters emit high-power radiofrequency radiation by creation of a high-voltage and high-frequency alternating electrical current. Methods: Health effects of occupational exposure to military radar were investigated. Visual reaction time was recorded with a simple blind computer-assisted-visual reaction time test. To assess the short-term memory, modified Wechsler Memory Scale test was performed. Results: The mean +/- SD reaction time in radar works (N=100) and the control group (N=57) were 238.58 +/- 23.47 milliseconds and 291.86 +/- 28.26 milliseconds (P<0.0001), respectively. The scores of forward digit span in radar works and the control group were 3.56 +/- 0.77 and 4.29 +/- 1.06 (P<0.0001), while the scores of backward digit span in radar works and the control group were 2.70 +/- 0.69 and 3.62 +/- 0.95 (P<0.0001). The scores of word recognition in radar works and the control group were 3.37 +/- 1.13 and 5.86 +/- 1.11 (P<0.0001). Finally, the scores of paired words in radar works and the control group were 13.56 +/- 1.78 and 15.21 +/- 2.20 (P<0.0001). It can be concluded that occupational exposures to radar radiations decreases reaction time, which may lead to a better response to different hazards. Conclusion: To the best of our knowledge, this is the first study to show that occupational exposure to radar microwave radiation leads to decreased reaction time and the lower performance of short-term memory. Altogether, these results indicate that occupational exposure to radar microwave radiations may be linked to some non-detrimental and detrimental health effects. نمایش موارد کمتر

Long-term manned exploratory missions are planned for the future. Exposure to high-energy neutrons, protons and high charge and energy particles during a deep space mission, needs protection against the detrimental effects of space radiation. It has been suggested that exposure to unpredictable extremely large solar particle events would kill the astronauts without massive shielding. To reduce this risk to astronauts and to minimize the need for shielding, astronauts with highest significant… نمایش موارد بیشتر

Long-term manned exploratory missions are planned for the future. Exposure to high-energy neutrons, protons and high charge and energy particles during a deep space mission, needs protection against the detrimental effects of space radiation. It has been suggested that exposure to unpredictable extremely large solar particle events would kill the astronauts without massive shielding. To reduce this risk to astronauts and to minimize the need for shielding, astronauts with highest significant adaptive responses should be chosen. It has been demonstrated that some humans living in very high natural radiation areas have acquired high adaptive responses to external radiation. Therefore, we suggest that for a deep space mission the adaptive response of all potential crew members be measured and only those with high adaptive response be chosen. We also proclaim that chronic exposure to elevated levels of radiation can considerably decrease radiation susceptibility and better protect astronauts against the unpredictable exposure to sudden and dramatic increase in flux due to solar flares and coronal mass ejections. نمایش موارد کمتر

Mercury is among the most toxic nonradioactive elements which may cause toxicity even at low doses. We have previously shown that release of mercury from dental amalgam fillings in individuals who used mobile phones and those who had a MRI was significantly increased. To overcome the limitations associated with our previous work, we selected students who had identical tooth decays, required a similar pattern of restorative dentistry and were exposed to a significantly higher magnetic flux… نمایش موارد بیشتر

Mercury is among the most toxic nonradioactive elements which may cause toxicity even at low doses. We have previously shown that release of mercury from dental amalgam fillings in individuals who used mobile phones and those who had a MRI was significantly increased. To overcome the limitations associated with our previous work, we selected students who had identical tooth decays, required a similar pattern of restorative dentistry and were exposed to a significantly higher magnetic flux density of 1.5 T produced by the currently used MRI machines. Sixteen students with identical dental decay, but otherwise healthy, participated in this study. They underwent similar restorative dentistry procedures and randomly divided into two groups of MRI exposed and control. Urinary concentrations of mercury in control subjects were measured before (hour 0) and 48 and 72 hours after amalgam restoration, using cold vapor atomic absorption spectrometry. Similarly, urinary concentrations of mercury in exposed individuals were determined before (hour 0), and 24, 48, 72 and 96 hours after amalgam restoration. However, unlike control subjects, they underwent conventional brain MRI (15 min, 99 slices), 24 h after amalgam restoration. Mercury levels in urine samples of MRI exposed and control individuals before amalgam restoration were 20.70±6.35 and 20.25±6.99, µg/l, respectively (P=0.87). Conversely, 48 h after MRI (72 h after restoration), mercury level in urine samples of MRI exposed and control students were 25.95±7.68 and 18.57±6.73 µg/l, respectively (P=0.038). Likewise, 72 h after MRI (96 h after restoration), again the mercury level in MRI exposed students was significantly (P=0.046) higher than that of control students (24.83±8.10 and 16.14±7.09 µg/l, respectively). These findings provide further evidence in favor of the notion that exposure to magnetic fields may significantly increase the release of mercury from dental amalgam fillings. نمایش موارد کمتر

BACKGROUND:

Modern life prompted man to increasingly generate, transmit and use electricity that leads to exposure to different levels of electromagnetic fields (EMFs). Substantial evidence indicates that exposure to common sources of EMF such as mobile phones, laptops or wireless internet-connected laptops decreases human semen quality. In some countries, mobile jammers are occasionally used in offices, shrines, conference rooms and cinemas to block the signal.
AIMS:

To the… نمایش موارد بیشتر

BACKGROUND:

Modern life prompted man to increasingly generate, transmit and use electricity that leads to exposure to different levels of electromagnetic fields (EMFs). Substantial evidence indicates that exposure to common sources of EMF such as mobile phones, laptops or wireless internet-connected laptops decreases human semen quality. In some countries, mobile jammers are occasionally used in offices, shrines, conference rooms and cinemas to block the signal.
AIMS:

To the best of our knowledge, this is the first study to investigate the effect of short term exposure of human sperm samples to radiofrequency (RF) radiations emitted by common mobile jammers.
SUBJECTS AND METHODS:

Fresh semen samples were collected by masturbation from 30 healthy donors who had referred to Infertility Treatment Center at the Mother and Child Hospital with their wives. Female problem was diagnosed as the reason for infertility in these couples.
STATISTICAL ANALYSIS:

T-test and analysis of variance were used to show statistical significance.
RESULTS:

The motility of sperm samples exposed to jammer RF radiation for 2 or 4 h were significantly lower than those of sham-exposed samples. These findings lead us to the conclusion that mobile jammers may significantly decrease sperm motility and the couples’ chances of conception.
CONCLUSION:

Based on these results, it can be suggested that in countries that have not banned mobile jammer use, legislations should be urgently passed to restrict the use of these signal blocking devices in public or private places. نمایش موارد کمتر

An article by Jin et al. “The Effect of Combined Exposure of 900 MHz Radiofrequency Fields and Doxorubicin in HL-60 Cells", published in the Sep 2012 issue of PLOS ONE Journal (Jin et al. 2012). The authors of the article reported some interesting findings on the induction of adaptive response by pre-exposure of HL-60 Cells to radiofrequency (RF) radiations. As summarized in Table 1, the viability of the cells exposed to DOX alone was 70.2 ± 0.2 while when cells were exposed to 900 MHz RF… نمایش موارد بیشتر

An article by Jin et al. “The Effect of Combined Exposure of 900 MHz Radiofrequency Fields and Doxorubicin in HL-60 Cells", published in the Sep 2012 issue of PLOS ONE Journal (Jin et al. 2012). The authors of the article reported some interesting findings on the induction of adaptive response by pre-exposure of HL-60 Cells to radiofrequency (RF) radiations. As summarized in Table 1, the viability of the cells exposed to DOX alone was 70.2 ± 0.2 while when cells were exposed to 900 MHz RF radiation at 12 μW/cm2 before treatment with DOX, the viability was 82.8 ± 2.1 (P<0.01). RF exposure at higher power densities significantly decreased the viability (60.7 ± 0.5 and 58.6 ± 0.5 for 120 μW/cm2 and 1200 μW/cm2, respectively). We and other investigators have previously reported that radiofrequency radiation can induce adaptive response phenomena (Haghani et al. 2012; Jiang et al. 2012; Mortazavi et al. 2011; Mortazavi et al. 2012; Sannino et al. 2009; Zeni et al. 2012). Jin’s findings as well as findings obtained in our studies (Mortazavi et al. 2012) clearly support the dose window theory that is well discussed for adaptive responses induced by ionizing radiation. As discussed by RE Mitchel, “the adaptive response in mammalian cells and mammals operates within a certain window that can be defined by upper and lower dose thresholds, typically between about 1 and 100 mGy for a single low dose rate exposure” (Mitchel 2010). On the other hand, as indicated by investigators who worked on ionizing radiation-induced adaptive responses (Bose Girigoswami and Ghosh 2005; Dimova, Bryant, and Chankova 2008; Yan et al. 2006), Jin’s findings on RF pre-exposures support this theory that the induction of adaptive response requires a minimum level of damage to trigger this phenomenon. In this light, it seems that there are similar patterns for induction of adaptive response by ionizing and non-ionizing radiations.
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