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Background: Humans beings are continuously exposed to ionizing radiation from natural sources. The main contributors to natural radiation are high-energy cosmic radiation and radioactive nuclides that originates in the earth’s crust. Exposure to high levels of radiation can cause serious health effects. In this study an attempt has been made to monitor the levels of environmental background radiation (gamma) in temples, historical monuments, schools and colleges, hostels, wedding halls and theaters in Mysore and Chamaraj Nagar districts and assess the possible effects on environment and human health. Materials and Methods: Environmental radiation dosimeter is used to measure the outdoor and indoor radiation absorbed dose levels. The measurements were made 1 m above the ground level. Results: Inside the temples it varies from 122.7 to 231.4 nGy.h–1 with a median of 130.1 nGy.h–1 outside the temples it varies from 141.8 to 340.2 nGy.h–1 with a median of 216.2 nGy.h–1. In different types of buildings in indoor atmosphere it varies from 112.2 to 197.5 nGy.h–1 with a median of 127.0 nGy.h–1 and in outdoor atmosphere it varies from 140.9 to 298.4 nGy.h–1 with a median of 216.2 nGy.h–1. Conclusion: The indoor absorbed dose rate is higher than outdoors in all types of constructions. Indoor and outdoor environment of the temples has higher levels of radiation than the historical monuments and other public and private building in Mysore and Chamaraj Nagar districts. Use of additional granite materials inside or outside the building will enhance the absorbed radiation dose levels. The values observed in the study area are comparable with other values observed in different parts of the world.

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Background: The study of rheological properties of blood has special interest since it is a circulating fluid exposed to shear rates during its life time. This work aims to investigate the influence of whole body gamma irradiation on the rheological properties of rat’s blood. The applied shear rate was from 12 to 375 s-1. Low shear viscosity (up to 100 s-1) depends mainly on the erythrocytes aggregation while the high shear viscosity depends on the erythrocytes deformability. Materials and Methods: Adult male rats were exposed to 1, 2.5, 3.5, 5, 7 and 9 Gy single doses. The consistency index, apparent viscosity, yield stress and aggregation index were increased after exposure to gamma radiation. The dielectric properties of the erythrocytes, in the low frequency range (60 Hz to 40 kHz), were measured in order to investigate the changes in the membrane surface charge. Results: The results obtained indicate that the viscosity, consistency index and yield stress increased after the exposure to the lowest dose taken 1 Gy, and continued to increase as the exposure dose increased up to dose 7 Gy and then decrease after exposure to 9 Gy. The relative permittivity and relaxation time showed significant decrease after exposure to the lowest dose and continue to decrease as the dose increased. Conclusion: The obtained results can be attributed to the decrease of membrane surface charge after exposure to gamma radiation. The decrease in the membrane surface charge is known to decrease the repulsion between the cells and increase blood viscosity. Iran. J. Radiat. Res., 2009 7 (1): 1117

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Background: Since 1996 the assessment of environmental gamma radiation dose in residential areas of Iranian towns and cities has been accomplished for 10 counties. As a practical method and based on the results of a pilot study, in order to attribute the final results to the whole residential area of a town five stations were selected for every town. The location of individual station was studied closely to comply with recommended conditions in the literature. Materials and Methods: RDS-110 was employed to measure gamma dose rate for one hour. Average annual dose rates plus conversion coefficients were employed to estimate gonad, bone marrow, equivalent and effective dose. Result: Minimum and maximum annual bone marrow and gonad dose equivalent attributed to environmental gamma are 0.24 mSvy-1 (for both tissues) and 1.44 and 1.46 mSvy-1, respectively. Conclusion: Average gonad and bone marrow doses for North Khorasan, Boshehr and Hormozgan provinces were less than the corresponding values for normal area. Iran. J. Radiat. Res., 2009 7 (1): 41-47

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Background: Similar to the thermoluminescence (TL) spectra, the optical parameters variations can also be used in TL crystals for dosimetry purposes. These optical parameters can include absorption, transmission and reflection coefficients. Materials and Methods: Single crystals of KBr and KCl which have been used in this research were grown from laboratory grade extra pure precursor powders. Crystal growth was performed by using a Czochralski crystal growth apparatus. The grown crystals were irradiated using a 60Co source to doses of 0.5, 1.0 and 1.5 kGy. Reflection spectra were measured by a Shimatzu UVPC 3101 model spectrometer in 5 and 45 incident degree angles. Results: Optical properties of KClxBr1-x mixed crystals surfaces irradiated with gamma radiation were determined. Refraction indices and dielectric coefficients of the crystals in the optical region of 250-750 nm were studied. It was observed that both irradiated and non-irradiated mixed crystals had similar surface behaviour in the order of n ≈ 1.4 and ε ≈ 2.2 in the whole range of 250-750 nm, while colour intensities of irradiated samples were different for various irradiation doses. The reason could have been due to the permanent heat transfer effects with the outer surface layers of the crystal and the rapid relaxation of the excited states in defected surface of the crystal. Conclusion: Reflection spectra along with the crystal surface optical parameters could not be efficient for the dosimetry purposes and additional information such as absorption or transmission data would also be necessary Iran. J. Radiat. Res., 2009 7 (3): 165-169

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Background: To evaluate the radioprotective potential of Punica granatum fruit rind extract (PGRE) in mouse testes. Materials and Methods: Adult male mice were divided into four groups. Group I was kept without any treatment. Group II was irradiated with 8Gy Co⁶⁰ gamma irradiation and Group III was given PGRE one hour before irradiation. Group IV was fed with PGRE at the rate of 10 mg/kg body weight. Mice were sacrificed at various post irradiation intervals and testes were removed, weighed and analysed biochemically for reduced glutathione content, Lipid peroxidation, Total protein, DNA and RNA content. Results were subjected to students ‘t’ test. Results: Testes weight of both the II group and III group decreased till 3rd post irradiation day. Protein and RNA contents increased up till the 3rd post irradiation day and decreased till 28th day in group II. Group IV maintains a higher level of protein and RNA content in comparison to II group. GSH and DNA content decreased in II group in comparison to normal and in III group they are found to be significantly higher at all the post irradiation intervals. Conclusion: Punica granatum fruit rind extract pretreatment renders protection against biochemical changes in mouse testes.

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Background: The aim of this study was to measure137Cs levels in soil and brick samples to set the baseline data and an indicator of fallout radioactivity for this part of the world. This study will help to probe, if there is any health threat posed by ¹³⁷Cs exposure to the residents of the area. Materials and Methods: Twenty five samples of soil and 6 samples of bricks were collected from different locations of Mirpur of Azad Kashmir. A P-type HPGe detector was used to measure gamma spectra of samples. Results: Results showed that for soil samples activity concentration range from 0.076±0.071 to 2.94±0.17 Bq.Kg^-1 with average value of 1.39±0.17 Bq.Kg^-1. Similarly activity concentration of ¹³⁷Cs in Brick samples range from 0.22±0.09 BqKg^-1 to 2.14±0.13 BqKg^-1 with average value of 0.73±0.10 Bq.Kg^-1. For soil samples the average values of outdoor, indoor and annual effective dose were found to be 5.12 × 10 ^–5, 20.47 × 10 ^–5 and 25.58 × 10 ^–5 mSv.y^-1 respectively. For brick samples specific activity of the ¹³⁷Cs range from 0.22±0.09 to 2.14±0.13 Bq Kg^-1. The average values of outdoor, indoor and annual effective dose for brick samples were 2.71 × 10 ^–5, 10.52 × 10 ^–5 and 13.23 × 10 ^–5 mSv.y^-1 respectively. Conclusion: The results indicate that the measured values were extremely small when compared with the annual dose rate recommended by ICRP (1.0 mSv.y^-1), as well as the annual external gamma radiation dose (0.48 mSv.y^-1) received per head from the natural sources of radiation.

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Background: Ramsar (Mazandran province) is known for its extremely high levels of natural background radiation. Although no excess cancer rate is reported in these areas by epidemiological studies, the study of tumor markers in the inhabitants of these areas may shed some light on the impact of high levels of background radiation on cancer induction. Materials and Methods: The level of background gamma radiation as well as indoor radon was determined using RDS-110 and CR-39 dosimeters. Thirty five individuals from a high background radiation area (HBRA) and 53 individuals from a normal background radiation area (NBRA) were randomly selected to participate in the study. Commercial ELISA kits (sandwich type ELISA tests) were used to measure the serum levels of PSA, CA15.3, CA125, Cyfra21-1, CEA, CA19.9, AFP and Tag72 tumor markers. Results: Among the eight biomarkers investigated, the means of PSA, CA15.3, CA125, CA19.9 and AFP concentrations between the HBRAs and NBRAs were not significantly different. However, Cyfra21, CEA and Tag72 in HBRA group revealed statistically significant increases compared to those of NBRA group (P<0.05). Furthermore, a statistically significant correlation between the external gamma dose as well as indoor radon level and the concentration of CEA (P<0.001), Cyfra-21(P<0.001) and TAG 72 (P<0.001 and 0.01 respectively) biomarkers were observed. Conclusion: Chronic exposure to high background radiation induces significant alterations in Cyfra21, CEA and Tag72 levels. We believe that studies with other relevant tumor markers might overcome the limitations of epidemiological studies on cancer incidence in high background radiation areas.

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Background: Dosimetry is a fundamental part of the radiation processing industry. Aqueous inorganic dosimeters have been used for gamma radiation dosimetry such as standard ferrous sulfate dosimeter. The purpose of this study was to investigate the effect of gamma radiation on the diethyl fumarate DEF in dimethyl sulfoxide DMSO solution and its possible use in chemical dosimetry. Materials and Methods: Three solutions having different concentrations of DEF were prepared (5, 10 and 20%) and exposed to various gamma doses. Irradiation was carried out using ROBO facility of ⁶⁰Co gamma ray. Absorbance was measured using Melton Roy 1201 UV-VIS spectrophotometer. Results: The absorption spectra of irradiated solution showed broad absorption bands between (325-400nm) with a shoulder at 332 nm. The absorbance increased with increasing the dose. Good response and linear relationship were found between absorbed dose and absorbance of 10% and 20% DEF concentration in the range of 0-225 kGy at the measured wavelength. Good dose rate independence was observed in the range of 14-33 kGy/h. It was noticed that irradiated samples had a good stability in darkness. Whereas, the response was affected during the storage in day light. This response was found to be depended on the irradiation temperature within the range of 18- 52 ⁰C. Conclusion: Our measurements showed that the ability of using the solution of diethyl fumarate DEF in dimethyl sulfoxide DMSO as a high dose radiation dosimetry. The useful dose range for 10% and 20% DEF of concentrations is up to 225 kGy. Nevertheless, the correction of temperature for routine dosimetry measurements should be taken into account.

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Background: The purpose of this work was to investigate the use of polyvinyl chloride (PVC) dyed with methyl red as a high dose radiation dosimetry. Materials and Methods: Commercial PVC films from Sabic made from resins PVC57S with thickness of 60 µm and methyl red with a molecular weight of 269.31 were used. Irradiation was carried out using a ⁶⁰Co γ-ray generator with sources arranged in rectangular holder with a total activity of 73.6926 kCi. Absorbance measurements were made by Jasco V- 630 UV-VIS spectrophotometer. Dose rate and irradiation temperature effects as well as post-irradiation storage in dark and indirect daylight conditions on dosimetry performance were also investigated. Results: The results showed a linear relationship between the relative absorbance (response) and the absorbed dose at the wavelength 548 nm in the range of 0-150 kGy. The response was found to be independent of both dose rate and irradiation temperature. Conclusion: The experimental results indicate that PVC films dyed with methyl red may be used for a high dose radiation dosimetry.

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