JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY
Year:2006 | Volume:- | Issue:1 (36)|Papers Count:10

The present pot study was carried out for comparison of N2 fixation ability for three main soybean cultivars in Iran i.,e. Sahar, Williams and Clark 63. The experiment was conducted under the proper growth chamber condition, with a randomized complete block design on a soil with no indigenous rhizobia and low nitrogen content. Each treatment was replicated four times. Each pot contained 3.5-kg air dried homogenized soil, and at the time of planting each seedling was inoculated with l ml of inoculums containing approximately 9×108 cells per ml. For quantifying the fixed nitrogen, using A-value (N-15) method, two solutions of N-15 enriched ammonium sulfate containing 9.616 and 2.086% N-15 atom excess were applied in amount of 6.67 and 33.33mg/kg N at the stage V2 for the fixing, and for the stages V2, R2 and R5 as reference pots. During 4 months of growth, the plants were irrigated with distilled water to maintain the soil moisture approximately 0.8 of the field capacity. The plants were harvested at the plant developmental stage reproductive 6 (R6) and a number of growth parameters were measured. According to the results, Sahar cultivar which is more lateness, showed a higher results in the most measured characteristics, including nitrogen derived from air, shoot dry matter, nodule dry matter and the whole dry matter of plant, significantly. All the three cultivars could supply more than 90 % of nitrogen demand through symbiosis. The cultivars were different significantly in amount of nitrogen derived from air, despite of the percent of nitrogen derived from air.

Prostate is a leading site for the cancer incidence, accounted for 31.0% of new cancer cases in men. Prostate-specific antigen (PSA) is widely used in the detection and monitoring of the prostate cancer. Currently, immunoassay is used to detect PSA in human serum. This technique is based on the interaction between antibody and antigen. The varied immunoassay formats and equipment to run the assays allow the users to measure the analytes rapidly, with the flexibility to run a small or a large number of samples. Among different immunoassay methods, immunoradiometric assay (IRMA) is a more sensitive and valuable detection approach. This study has been made in 4 parts: (1) purification of PSA from seminal fluid; (2) preparation of hybridoma cells which secrete monoclonal antibody (mAb) against PSA, (3) selection of pair monoclonal antibody among those antibodies, and finally (4) design of an IRMA kit and its quality control. The results of this study were: (1) obtaing a huge amount of PSA as semi-purified and purified, that is a valuable material for preparation of standard kits; (2) preparation of 8 kinds of monoclonal antibodies; (3) finding 4 pairs of monoclonal antibodies which react with different epitopes on PSA molecule; and (4) preparation of IRMA kit for measuring PSA concentration in human serum.

In this work, the capacity of an extreme halophilic archaebacterium, isolated from Uromia lake, Haloferax radiotolerans to withstand the lethal effects of ultraviolet light (UV), and 60Co r-rays has heen studied. The resistibility of this organism against the DNA-damaging agents was evaluated by calculating of the survival fractions at different dose rates of UV and 60Co r-rays radiations and compared with those of Escherichia coli B/r (a radioresistant strain of E. coli). D37 values for Haloferax radiotolerans and E. coli B/r were 231, and 9 J/m2, respectively, by exposure to the UV light. They were 645, and 99 Gy, respectively, by exposure to 60Co r-rays. Against these agents, Haloferax radiotolerans shows much more resistance compare to that of E. coli B/r. This is catogorized as the first report of resistibility in the member of Archaea.

The exploration research in the Khoshoomi region, located at the north east (~180km) of Yazd has shown that the area is benfitted from a good uranium reservation. After leaching the samples, the concentration of uranium was evaluated to be 1200±20 mg/l. By solvent extraction, stripping, precipitation and calcination processes, the uranium oxide (U3O8) was produced. The purity and recovery percentages of U3O8 were 70% and 85%, respectively, which are acceptable according to the international documents. It is concluded that the organic phase, containing 3% (vol) Alamine 336+2% (vol) normal dodecanol in aliphatic kerosene, has a good capability for separation of uranium from anomaly no. 6, of Khoshoomi region sulfuric acid leaching solutions. Applying Mc Cabe-Thiele method, with 2 counter current extraction stages, and 2 stripping stages (15% w/v) sodium bicarbonate solution), separation of uranium is feasible. The percentage of recovery, purity of product and feasibility of the chemical processes show that Khoshoomi mine is capable for producing uranium oxide (U3O8). For stablishing a new uranium mine at this region, however a more technical and engineering information is needed.

Sodium fluoride (Na18F) is the positron emission tomography (PET) radiopharmaceutical for skeletal imaging. The fluoride-18 ions are produced in NRCAM cyclotron IBA, Cyclone-30 by bombardment of enriched water (H218O) with accelerated protons. The produced fluoride-18 ions are converted to injectable sodium fluoride solution. Then, the quality control of sodium fluoride solution is carried out with identification of the radionuclide, radiochemical and chemical purity, pyrogenicity and sterility. After the quality control, the sodium fluoride solution is injected into the rate’s lesion and the distribution of fluoride-18 ions is investigated with imaging by the use of a dual-headed coincidence system. In this paper the process and parameters of the production, methods of the quality the control, and the coincidence images of the rat's lesions and the distribution of fluoride-18 ions are described. The obtained images show that the maximum uptake of the fluoride-18 ions is in the bone lesions.

In this study, the design of a low power gold vapor laser is presented. The laser tube is an alumina ceramic of cylindrical shape, having the length of 58cm and the inner bore diameter of 11mm. The maximum applied DC voltage is 4.2kV, and the average current is ~ 390mA. The system is operating at the pulse repetition rate of 18.2 kHz, with 40 mbar neon gas pressure. The maximum measured output power in sealed off and gas flow conditions are 710 and 450mW, respectively. The operational behavior of the present system has been compared with that of a copper vapor laser of the same dimensions, showing that the power efficiency is much lower in the case of the gold vapor laser. While both systems have similar time behavior and introducing similar response to the operational gas pressure, it seems, however, the laser output powers versus the pulse repetition rate are different in each laser. The measured output power versus the neon gas pressure has a maximum at 60 mbar gas pressure with a cutoff which occurs at 170 mbar.

Carbon nanotubes (CNTs) were grown on nickel catalysts by thermal chemical vapor deposition (TCVD), using CH4 as precursors, at atmospheric pressure. Ion beam sputtering has been used for Ni deposition on various silicon substrates. In this study, the effect of oxided silicon surface on the Ni agglomeration and CNTs growth was investigated, using scanning electron microscopy (SEM) and micro-Raman. SEM results show the role of silicon oxide film on the silicon (SiO2/Si), concerning agglomeration of Ni layer and hence, the CNTs growth. The graphite structure of the tubes was confirmed by Raman spectroscopy.

A precise procedure is used for determination of chloride in the nuclear grade zircaloy (containing <20 ppm chloride) which is necessary in the nuclear industry. In this investigation, an appropriate method for chemical analysis of chloride in zirconium metal and zirconium alloys is developed. In this approach the effective parameters in Turbidity such as pH, residence time of solutions in darkness, silver ion concentration and light effects have been investigated and optimized. The proposed method is compared with the spectrophotometric determination of chloride by mercury (II) thiocyanate through calibration and standard addition methods. The obtained results by turbidimetric and nephelometric methods are confirmed with the spectrophotometric method. In the range of 0.1-2ppm, the concentration and turbidity are linearly related, having a correlation coefficient of r=0.997. The detection limit of the proposed method is 0.03 ppm and the relative standard deviation for five repeated experiments of 0.2, 0.5, 1.0 and 1.5ppm of chloride are 9.0, 6.2, 3.0 and 2.0 percent, respectively.