84 research outputs found

    THE MANUFACTURE OF THE GRAPHITE-URANIA FUEL MATRIX FOR TREAT. Final Report--Metallurgy Program 7.6.9

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    The fabrication of the graphite-urania fuel blocks to be used in the Transient Reactor Test is described. A flowsheet of the fabrication process and an evaluation of the fabricated blocks are presented. (C.J.G.

    THE ZrOsub2sub 2-CaO-UOsub2sub 2 CERAMIC FUEL FABRICATION FOR THE EBWR SPIKED CORE ELEMENTS. Final Report-Metallurgy Program 7.9.5

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    A series of experiments was proposed in which the thermal output of the EBWR is increased to 100 Mw. The increase in thermal enengy will be accomplished by inserting 32 spike elements in the initial fuel core. The fuel selected for the spike elements was a cubic solid solution in the system ZrO/sub 2/- CaO- UO/ sub 2/. The ceramic fuel was fabricated in the form of pellets by compacting a mixture of U/sub 3/O/sub 8/, CaCO/sub 3/, and ZrO/sub 2/. The pressed pellets were sintered in air at 1675 deg C plus or minus 25 deg C to form a cubic solid solution having a composition of 9.01 wt.% UO/sub 2/ (93% enriched), 9.07 wt.% CaO, and 81.92 wt.% ZrO/sub 2/. The procedures used in forming the fuel pellets are described. Following fabrication, the pellets were loosely inserted into Zircaloy-2 tubes for subsequent assembly into fuel elements. (auth

    The effect of food availability, age or size on the RNA/DNA ratio of individually measured herring larvae: laboratory calibration

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    RNA/DNA ratios in individual herring (Clupea harengus) larvae (collected from Kiel Bay, Baltic Sea, in 1989) were measured and proved suitable for determining nutritional status. Significant differences between fed and starving larvae appeared after 3 to 4 d of food deprivation in larvae older than 10 d after hatching. The RNA/DNA ratio showed an increase with age or length of the larvae and was less pronounced in starving larvae compared to fed larvae. The individual variability of RNA/DNA ratios in relation to larval length of fed larvae and of larvae deprived of food for intervals of 6 to 9 d is presented. Based on the length dependency and the individual variability found within the RNA/DNA ratios, a laboratory calibration is given to determine whether a larva caught in the field has been starving or not. An example for a field application is shown

    Presymptomatic breast cancer in Egypt: role of BRCA1 and BRCA2 tumor suppressor genes mutations detection

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    <p>Abstract</p> <p>Background</p> <p>Breast cancer is one of the most common diseases affecting women. Inherited susceptibility genes, <it>BRCA1 </it>and <it>BRCA2</it>, are considered in breast, ovarian and other common cancers etiology. <it>BRCA1 </it>and <it>BRCA2 </it>genes have been identified that confer a high degree of breast cancer risk.</p> <p>Objective</p> <p>Our study was performed to identify germline mutations in some exons of <it>BRCA1 </it>and <it>BRCA2 </it>genes for the early detection of presymptomatic breast cancer in females.</p> <p>Methods</p> <p>This study was applied on Egyptian healthy females who first degree relatives to those, with or without a family history, infected with breast cancer. Sixty breast cancer patients, derived from 60 families, were selected for molecular genetic testing of <it>BRCA1 </it>and <it>BRCA2 </it>genes. The study also included 120 healthy first degree female relatives of the patients, either sisters and/or daughters, for early detection of presymptomatic breast cancer mutation carriers. Genomic DNA was extracted from peripheral blood lymphocytes of all the studied subjects. Universal primers were used to amplify four regions of the <it>BRCA1 </it>gene (exons 2,8,13 and 22) and one region (exon 9) of <it>BRCA2 </it>gene using specific PCR. The polymerase chain reaction was carried out. Single strand conformation polymorphism assay and heteroduplex analysis were used to screen for mutations in the studied exons. In addition, DNA sequencing of the normal and mutated exons were performed.</p> <p>Results</p> <p>Mutations in both <it>BRCA1 </it>and <it>BRCA2 </it>genes were detected in 86.7% of the families. Current study indicates that 60% of these families were attributable to <it>BRCA1 </it>mutations, while 26.7% of them were attributable to <it>BRCA2 </it>mutations. Results showed that four mutations were detected in the <it>BRCA1 </it>gene, while one mutation was detected in the <it>BRCA2 </it>gene. Asymptomatic relatives, 80(67%) out of total 120, were mutation carriers.</p> <p>Conclusions</p> <p><it>BRCA1 </it>and <it>BRCA2 </it>genes mutations are responsible for a significant proportion of breast cancer. <it>BRCA </it>mutations were found in individuals with and without family history.</p

    Experimental Evidence for an Interface Delocalization Transition in Cu3Au\mathrm{Cu_3Au}

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    The Cu3_3Au(100) surface has been studied close to the bulk order-disorder transition temperature T0_0 by x-ray diffraction under total external reflection. The order-parameter profile which has been probed in various depths is analyzed in terms of a surface-induced disorder transition. It is demonstrated that the temperature dependence of the superlattice intensity is consistent with the assumption of a disordered surface layer which exists between the ordered bulk and the vacuum at temperatures below T0 and grows logarithmically as T0_0 is approached
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