In this research, using Geant4 Monte Carlo simulation tool, we have investigated the shielding properties of aluminum oxide, magnesium fluoride, aluminum fluoride, titanium dioxide, magnesium diboride, magnesium silicide, calcium disilicate, and Fluental in the energy range of 0.015 to 10 𝑀𝑒𝑉. In this review, we have calculated and analyzed the linear attenuation coefficient (LAC) and mass attenuation coefficients (MAC), half-value layer (HVL), tenth value layer (TVL), mean free path (MFP), and effective atomic number, effective electron density, equivalent atomic number and buildup factor. In the continuation of the work, we have compared the calculated results of mass attenuation coefficient by Geant4 Monte Carlo simulation tool with the experimental results of others and with the simulation data by XMuDat code, and they have a very low relative error and are in good agreement with each other. Finally, the results obtained for the selected materials are shown in appropriate figures.

Background: Eucalyptus oil often used for medicinal purposes. Aims: The Eucalyptus oil gastro protective impact investigated against Gamma-rays-exposure-induced gastric ulceration in rats. Materials and Methods: Thirty-two rats were divided equally into 4groups,control, Eucalyptus oil (100mg/ kg), Gamma-rays (7Gy) and Eucalyptus oil plus Gamma-rays treated groups. The stomach histopathology samples were examined. The levels of malondialdehyde, reduced glutathione, superoxide dismutase, tumour necrosis factor-α,and the interleukin-1β,were assessed. Results: The stomach histopathological examination revealed that pre-treatment with Eucalyptus oil enhanced regeneration of mucosal crypt cells. The results revealed a decreased level of stomach malondialdehyde, inflammatory markers, increased levels of stomach antioxidants markers in Eucalyptus oil plus Gamma-rays treated group. Conclusion: Eucalyptus oil ameliorates Gamma-rays-induced gastric ulceration that could attribute to its antioxidant, anti-apoptotic and radioprotective activities.

Muon-electron ratio and median zenith angle of Extensive Air Shower (EAS) is calculated for the energy range of 1019 to bigger than 1020 eV. The results are compared with the simulation work of Capdevielle et al. The results show a good correspondence with proton primary composition up to energy level of 7×1019 eV. In higher energies above GZK cut off, a considerable increase is calculated in cosmic primary photons. In addition, event frequency distribution above energy 7×1019 eV shows increasing concentration towards super galactic plane.

Objective: To assess relative biological effectiveness (RBE) of 131I radiation relative to 60Co Gamma rays in glioblastoma spheroid cells. Materials and Methods: In this experimental study, glioblastoma spheroid cells were exposed to 131I radiation and 60Co Gamma rays. Radiation induced DNA damage was evaluated by alkaline comet assay. Samples of spheroid cells were treated by radiation from 131I for four different periods of time to find the dose-response equation. Spheroid cells were also exposed by 200 cGy of 60Co Gamma rays as reference radiation to induce DNA damage as endpoint. Results: Resulted RBE of 131I radiation relative to 60Co Gamma rays in 100mm giloblas-toma spheroid cells was equal to 1.16.Conclusion: The finding of this study suggests that 131I photons and electrons can be more effective than 60Co Gamma rays to produce DNA damage in glioblastoma spheroid cells.

Background: Recently, it has been demonstrated that thermosetting polymer composites have excellent Gamma-rays shielding properties. Among them, phthalonitrile composites are the best suitable materials to replace the traditional shielding materials such as lead and concrete. Furthermore, tungsten-boride as high Zmaterial is an effective ionizing radiation shield. Materials and Methods: The Gamma rays shielding properties of the phthalonitrile matrix (PH) reinforced with tungstenboride (WB) at 661, 1172, and 1332 keV photon energies were investigated using MCNPX code and XCOM tool kit and compared to those of concrete as conventional shielding material and epoxy composites. MCNPX geometry was defined along the zaxis and described in the input file. The number of emitted photons was fixed at 107 at the source, which is supposed to be a monoenergetic point. Results: The simulated mass attenuation coefficients results are in good agreement with those calculated using the XCOM tool kit. Also, it was observed that at 661 keV photon energy, the shielding performances in term of Half-Value-Layer (HVL) are enhanced by3. 08% and 22. 01% for 30% and 50% of tungsten-boride concentrations compared to 30% of PbO concentration in the Epoxy-Clay composite and concrete respectively. Conclusion: In this study, the outstanding results of Gamma-rays shielding properties of Phthalonitrile/WB composites (PHWB) obtained using MCNPX code and XCOM can be used for future experimental Gamma-rays shielding approaches at a wide range of energy.

Background: The trabecular bone changes in the tibia of C3H/HeN mice were measured 12 weeks after whole body irradiation with various doses of fast neutrons (0-2.4 Gy) or 137Cs-generated Gamma-rays (0-6 Gy).Materials and Methods: Serum calcium, phosphorus, estradiol concentration and alkaline phosphatase activity were measured. Tibiae were analyzed using microcomputed tomography. Biomechanical property and osteoclast surface level were measured.Results: There was a significant relationship between the loss of bone architecture and the radiation dose, and the best-fittng dose-response curves were linear-quadratic. Mean relative biological effectiveness (RBE) values (Ref. Gamma) of 2.05 and 2.33 were estimated for fast neutron irradiation in trabecular bone volume fraction and bone mineral density, respectively. There was a substantial reduction in osteoclast surface level in tartrate-resistant acid phosphatase-stained histological sections of tibial metaphyses in irradiated mice with high dose of neutrons.Conclusion: There was a significant relationship between the loss of bone architecture and the radiation dose. The difference of osteoclastic bone resorption may represent a contributor to the low RBE in high dose of irradiation level relative to that of low dose level.