1,880 research outputs found

    The Application of Laser Induced Breakdown Spectroscopy to Molten Salt Corrosion

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    Molten salt reactors (MSRs) have a plethora of advantages over light water reactors. The operate at more favorable conditions for power generation and accident conditions. These conditions lead to problems with corrosion. Monitoring of this corrosion will be required for a MSR when built. Laser Induced Breakdown Spectroscopy (LIBS) is an excellent tool for this application, as it can be done with minimal sample preparation and without having to complete the more complex sample preparation required for EDS. This work will demonstrate the utility of LIBS in showing similar features as EDS such that an understanding of the corrosion seen in a material is achieved through LIBS

    Quality of Life After Bilateral Adrenalectomy in MEN 2

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    Pheochromocytoma is a major cause of morbidity and mortality in the multiple endocrine neoplasia type 2 (MEN 2) syndrome. For the physician, surgical treatment seems well justified even though bilateral adrenalectomy will induce iatrogenically complete loss of adrenocortical function. For the patient this treatment may be a cause of medical problems as well as worry. We have evaluated quality of life after bilateral adrenalectomy in 27 MEN 2 patients through a combined oral and written approach. Mortality was low (one of 27), as was serious morbidity. Most patients had adapted well to the postadrenalectomy state. However, fatigue, worry, and noncompliance with daily medication often caused problems

    An evaluation of the implementation of Georgia's Pre-k program: Report of the findings from the Georgia Early Childhood Study (2002-03)

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    After ten years, Georgia continues to lead the nation in providing full day, publicly subsidized Pre-K to four-year-olds whose parents choose to enroll them. In this report, we assess the extent to which differences in the way Pre-K is implemented affect children's development. Do teachers with higher levels of education have more positive impacts on children's development? Do teaching styles make a difference in terms of children's outcomes by the end of kindergarten? Do children taught using certain curricula fare better than those taught using others? Answers to questions such as these can assist Pre-K administrators in refining Georgia's program and inform those in other states who are developing or expanding their prekindergarten programs

    A microfluidic chip based model for the study of full thickness human intestinal tissue using dual flow

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    © 2016 Author(s). The study of inflammatory bowel disease, including Ulcerative Colitis and Crohn's Disease, has relied largely upon the use of animal or cell culture models; neither of which can represent all aspects of the human pathophysiology. Presented herein is a dual flow microfluidic device which holds full thickness human intestinal tissue in a known orientation. The luminal and serosal sides are independently perfused ex vivo with nutrients with simultaneous waste removal for up to 72 h. The microfluidic device maintains the viability and integrity of the tissue as demonstrated through Haematoxylin & Eosin staining, immunohistochemistry and release of lactate dehydrogenase. In addition, the inflammatory state remains in the tissue after perfusion on the device as determined by measuring calprotectin levels. It is anticipated that this human model will be extremely useful for studying the biology and tes ting novel interventions in diseased tissue

    A Mutation in Amino Acid Permease AAP6 Reduces the Amino Acid Content of the Arabidopsis Sieve Elements but Leaves Aphid Herbivores Unaffected.

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    The aim of this study was to investigate the role of the amino acid permease gene AAP6 in regulating phloem amino acid composition and then to determine the effects of this altered diet on aphid performance. A genotype of Arabidopsis thaliana (L.) was produced in which the function of the amino acid permease gene AAP6 (At5g49630) was abolished. Plants homozygous for the insertionally inactivated AAP6 gene had a significantly larger mean rosette width than the wild type and a greater number of cauline leaves. Seeds from the aap6 mutant were also significantly larger than those from the wild-type plants. Sieve element (SE) sap was collected by aphid stylectomy and the amino acids derivatized, separated, and quantified using Capillary Electrophoresis with Laser Induced Fluorescence (CE-LIF). In spite of the large variation across samples, the total amino acid concentration of SE sap of the aap6 mutant plants was significantly lower than that of the wild-type plants. The concentrations of lysine, phenylalanine, leucine, and aspartic acid were all significantly lower in concentration in the aap6 mutant plants compared with wild-type plants. This is the first direct demonstration of a physiological role for an amino acid transporter in regulating SE composition in vivo. The amino acid availability in sieve element sap is thought to be the major limiting factor for aphid growth and reproduction. Despite the changes in their diet, the aphid Myzus persicae(Sulzer) displayed only small changes in feeding behaviour on mutant plants when measured using the Electronic Penetration Graph (EPG) technique. Salivation by the aphid into the SE (E1 phase) was increased on mutant plants but there was no significant effect on other feeding EPG behaviours, or in the rate of honeydew production. Consistent with the small effect on aphid feeding behaviour, there was only a small effect of reduced sieve element amino acid concentration on aphid reproduction. The data are discussed in relation to the regulation of phloem composition and the role of phloem amino acids in regulating aphid performance

    Steric constraints in model proteins

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    A simple lattice model for proteins that allows for distinct sizes of the amino acids is presented. The model is found to lead to a significant number of conformations that are the unique ground state of one or more sequences or encodable. Furthermore, several of the encodable structures are highly designable and are the non-degenerate ground state of several sequences. Even though the native state conformations are typically compact, not all compact conformations are encodable. The incorporation of the hydrophobic and polar nature of amino acids further enhances the attractive features of the model.Comment: RevTex, 5 pages, 3 postscript figure
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