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Introduction: Nowadays, cancer is the second cause of mortality in the world. Gastric cancer has a high mortality rate (about 70%) which is more common in men and has a higher incidence in eastern Asian countries. One of the methods for cancer treatment is radiotherapy, in which to enhance the efficiency of radiation therapy some of radio-sensitizer agents can be used to enhance tumor cell radiosensitivity. Some nanoparticles can be considered as a sensitizer because of enhancing the cytotoxicity to oxidative stress and increasing free radicals especially ROS within cells, resulting to cell death. In this study, synergistic effect of TiO2 nanoparticles as a radio-sensitizer agent was evaluated in the presence of cobalt-60 gamma rays on human gastric cancer cell line. Materials and Methods: After cell culture, MKN-45 cells were exposed to 2 Gy of radiation and 30 µg/ml concentration of nanoparticles. Viability was calculated using MTT assay. Findings: Exposing cultured cells to nanoparticles alone resulted to a mean decrease of 70% in cell survival. Viability of cells in presence of gamma radiation and nanoparticles was significantly reduced compared to the viability of cells exposed only to radiation or nanoparticle, alone. The effect was dependent both on the nanoparticle crystal type and concentration. Discussion & Conclusion: Nano-TiO2 increased the sensitivity of gastric cancer cells to gamma radiation, due to an increase in the ROS production and cytotoxicity. Anatase crystals have more severe effects than rutile crystal because of having a larger surface area and creation of more free radicals. Therefore, this nanoparticle has the potential to be used as a radio-sensitizer.

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Background and Objectives Chromium is a common contaminant in ground and surface water, soil and waste water. Chromium is of considerable because of toxicity and environmental and human health. The aim of this research were to synthesize magnetite nanoparticles (Fe3O4) and determining its efficiency in chromium removal from aqueous solutions. Materials and Methods: magnetite nanoparticles were synthesized and the effects of pH and contact time on cadmium removal efficiency were investigated in batch system. Then kinetics and isotherm models coefficients were determined based on optimum conditions. Scanning Electron Microscopy (SEM), XRD were used to characterization of the synthesized magnetite nanoparticles. Results: SEM results showed that the diameter of the particles is 40-50 nm. Results showed that the optimum pH value for chromium adsorption was 2 and the equilibrium time was 60 min. The magnetite nanoparticles have advantages such as high removal efficiency and short reaction time and can be used as a method to remove cadmium from aqueous solutions. The adsorption kinetics fitted using the type1- pseudo second-order kinetic model and the adsorption isotherm could be described by the langmuer. The langmuer maximum adsorption capacity of magnetite nanoparticles for Cr(VI) was found to be 24 mgg-1. Conclusion: These results indicated that magnetite nanoparticles can be employed as an efficient adsorbent for the removal of chromium from contaminated water sources. The results also revealed that the magnetite nanoparticles supported have a better adsorption capacity, better magnetic properties and separation, and therefore, lower cost.

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Introduction: Nowadays, potential risks have been well known for human health which associated with toxic heavy metals in environment.Cadmium is one of the most important heavy metals that its presence in aquatic environment have created many concerns due to high toxicity at low concentrations and the ability to accumulate in living tissues. several methods have been studied to remove of heavy metals but, using low prices absorbents has been considered by researchers to remove these metals in recent years . in this research, we will study cadmium removal by natural clinoptilolite zeolite.
 Material s & methods: The experiments were conducted with natural zeolite discontinuous . To determine the characteristics of zeolite, Scanning Electroni Microscop (SEM) and X-ray diffraction Device (XRD) have been used . effect of some parameters have studied on efficency of cadmium elimination and adssorption isotherms, including: PH (2,4,6,8,10), contact time (30, 60, 90, 120, 150 min), adsorbant dosage (0.2,0.5,0.8,1,2 gr) and mtetal ion concentration (10, 50, 100 mg/L).
 Findings: According to absorption of cadmium process results, The optimum PH was equal 6 with removal efficencies of 83.3% and equiliberium time of 90 minuts with removal efficencies of 93.1%,. As expected, The amount of absorbed cadmium ereduced by increasing the concentration of cadmium. Between both models Langmuir and Freundlich isotherm, Langmuir model have described cadmium adsorption of cadmium on the adsorbent better than Freundlich.
Discussion & Conclusion: The results of current study have indicated that natural linoptilolite zeolite can be used as an efficient and I nexpensive absorbent to elemination of cadmium in aquatic environments.