Pyrolytic graphite as an efficient second-order neutron filter at tuned positions of boundary crossing

An investigation of pyrolytic graphite (PG) crystal as an efficient second order neutron filter at tuned boundary crossings has been carried out. The neutron transmission through PG crystal at these tuned crossing points as a function of first- and second-order wavelengths were calculated in terms of PG mosaic spread and thickness. The filtering features of PG crystals at these tuned boundary crossings were deduced. It was shown that, there are a large number of tuned positions at double and triple boundary crossings of the curves (hkl) are very promising as tuned filter positions. However, only fourteen of them are found to be most promising ones. These tuned positions are found to be within the neutron wavelengths from 0.133 up to 0.4050 nm. A computer package GRAPHITE has been used in order to provide the required calculations in the whole neutron wavelength range in terms of PG mosaic spread and its orientation with respect to incident neutron beam direction. It was shown that 0.5 cm thick PG crystal with angular mosaic spread of 2o is sufficient to remove 2nd-order neutrons at the wavelengths corresponding to the positions of the intersection boundaries curves (hkl)

The applicability of D2 gastrectomy in operable gastric cancer patients: A trial of Alexandria Surgical Oncology Unit

Background: There is ongoing controversy in patients with early gastric cancer over whether a lymph node resection beyond a D1 lymphadenectomy is beneficial. Experienced gastric surgery centers, especially in Japan and Korea, have argued that a more extensive lymph node dissection that incorporates the next echelon of lymph nodes (D2 lymphadenectomy) improves staging and outcome in gastric cancer patients. Aim of the work: Was to assess the feasibility and safety of D2 gastrectomy in patients presented by operable gastric cancer. Patients and Methods: The study included thirty patients with operable gastric cancer who were treated by D2 gastrectomy after preoperative assessment by laboratory and radiological investigations. They were followed post operatively for complications and hospital stay and the histopathological criteria were assessed and analyzed. Results: Twenty six patients had pyloric tumors and four having gastric body tumors were included. Postoperative complications occurred in 20% of cases, these included wound infection, bile leak, ascites and chest infection. Conclusion: D2 gastrectomy for gastric cancer is a safe procedure for patients with operable gastric cancer. KEYWORDS: Gastric cancer, D2 gastrectom

Effect of Using Stabilizing Agents on Increasing Yield and Water Use Efficiency in Barley Grown under Water Stress

Abstract: Two field experiments were conducted during the two successive seasons of 2004/05 and 2005/06 at the Agricultural Experimental Station of National Research Centre, Shalakan, Kalubia Governorate, Egypt to predict the effect of two yield stabilizing agents (magnesium carbonate and sodium salicylate) on barley yield and water use efficiency under skipping the last irrigation. Four hulled barley cultivars were used i.e. Giza 123, Giza 125, Giza 126, and Giza 2000, in addition to, two hull-less barley cultivars i.e. Giza 129 and Giza 130. Magnesium carbonate or sodium salicylate was sprayed twice during vegetative growth and the last irrigation was skipped. At heading, number of tillers/plant, number of spikes/plant and plant height were measured. Furthermore, at harvest, grain yield, straw yield and biological yield were determined. Data for mean temperature and relative humidity were collected from planting date to heading date and averaged over the two growing seasons. Simple correlation analysis and multiple linear regression analysis were done. Results indicated that the highest reduction in yields as result of skipping the last irrigation was obtained for Giza 126. W hereas, the lowest reduction in grain, straw and biological yields were obtained for the two hull-less cultivars. The application of magnesium carbonate had better effect on the yield of barley cultivars than the application of sodium salicylate. The highest water use efficiency was obtained for Giza 123 under all irrigation treatments, especially under the application of magnesium carbonate. Results also showed that both temperature and relative humidity were highly and negatively correlated with barley yields. Number of tillers/plant and number of spikes/plant were positively correlated with barley grain, straw and biological yields, and plant height, was negatively correlated with grain yield. The developed prediction equations could be a useful decision-making tool to attain early yields prediction, which could be helpful in deciding whether to skip the last irrigation or not

2 keV filters of quasi-mono-energetic neutrons

A simulation study for the production of 2 keV filters of quasi-mono-energetic neutrons based on the deep interference minima in the 45Sc total cross-section was carried out. A computer code QMENF-II was adapted to calculate the optimum amounts of the 45Sc as a main filter element and additional component ones to obtain sufficient intensity at high resolution and purity of the filtered quasi-mono-energetic neutrons. The emitted neutron spectrum from nuclear reactor and from the reaction of 2.6 MeV protons on a lithium fluoride target at the accelerator beam port, are used for simulation