Sharif Digital Repository

Photo-transmutation of hazardous long lived radioactive 107Pd induced by bremsstrahlung and Compton scattering is carried out. Photonuclear reactions is investigated by irradiating a 2 mm tantalum target with a 10 21 W cm-2 μm2 laser intensity into a 1 cm thick 107Pd target placed directly behind it. Based on the reported data by intense and well-collimated gamma photon beams generated by inexpensive inverse Compton scatterings of a 100 W CO2 laser and the 3.5 GeV high energy electron, a suitable theoretical formalism is presented. The scattered energy and the differential cross section are characterized as a function of scattering angle. It is found that the number of reactions in the... 

Nanoparticles of high-Z elements exhibit stronger photoelectric effects than soft tissues under gamma irradiation. Hence, they can be used as effective radiosensitizers for increasing the efficiency of current radiotherapy. In this work, superparamagnetic zinc ferrite spinel (ZnFe2O4) nanoparticles were synthesized by a hydrothermal reaction method and used as radiosensitizers in cancer therapy. The magnetic nanoparticles showed fast separation from solutions (e.g., ~ 1 min for 2 mg mL- 1 of the nanoparticles in ethanol) by applying an external magnetic field (~ 1 T). The ZnFe2O4 nanoparticles were applied in an in vitro radiotherapy of lymph node carcinoma of prostate cells (as high... 

Foams for biomedical applications were made from polyvinyl alcohol, polyvinyl alcohol / polyvinyl pyrrolidone blend and their nanocomposites with nanoclay by clean processes. Air was entrapped into the aqueous polymer solutions during vigorous mixing and then the solutions were freeze-dried. The foams structure was stabilized by crosslinking via gamma irradiation without using any harmful chemicals. The hydrophilic biocompatible foams possessed interconnected open cell structure with remarkable capacity to absorb and retain water. The foams in wet state were soft and flexible. Desirable pore structure and higher water absorption was obtained at a solution concentration of 5 wt% for both... 

Gamma irradiation systems are used extensively in the industry in order to sterilize medical devices, disinfect hygienic products and increase the shelf life of agricultural products. The method of gamma irradiation is superior to the older methods of heat or chemical treatment because it is by far a simpler operation. In this method, only one parameter, the exposure time is controlled, whereas in the other mentioned methods five or six different parameters need to be controlled. The design of irradiation systems generally includes the size and the location of products, and the arrangement of source rack pencils. In order to optimize the design of the gamma irradiation systems, it is needed... 

We previously reported that MR01, an indigenous strain of Pseudomonas aeruginosa, was able to produce a rhamnolipid-type biosurfactant. Here, we attempted to define the structural properties of this natural product. The analysis of the extracted biosurfactant by thin-layer chromatography (TLC) revealed the presence of two compounds corresponding to those of authentic mono- and di-rhamnolipid. The identity of two structurally distinguished rhamnolipids was confirmed by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. Liquid chromatography/mass spectrometry (LC/MS) of extracted biosurfactant revealed up to seventeen different rhamnolipid congeners. Further quantification showed...