825 research outputs found

    Comparison of added mass coefficients for a floating tanker evaluated by conformal mapping and boundary element methods

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    One of the important parameters needed to model ship motions in a seaway is the added mass matrix of the hull. Current state-ofthe- art boundary element methods routinely evaluate the 6 x 6 added mass matrices as part of the radiation problem solution. These developments have largely superseded conventional approaches to sectional added mass evaluation using conformal mapping techniques. However, conformal mapping techniques are still attractive in terms of their mathematical explicitness and computational simplicity. The recurrent form of Bieberbach Method of conformal mapping was developed for mapping the exterior of a closed curve i.e. the two-dimensional ship cross section and its mirror image, into the exterior of the circle oscillating vertically at free surface and to compute the added mass coefficients. By incorporating a strip theory approximation the added mass coefficients of a three dimensional structure can be estimated from its two-dimensional section coefficients at different drafts. In this paper we have applied this method to calculate the heave, pitch and heave induced pitch added mass coefficients of a tanker. The applicability of these conformal mapping techniques to floating platforms under consideration is discussed, by comparing the results with state-of-the-art industry standard boundary element methods, AQWA and SESAM

    Ergonomy in laboratory animal care

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    Comparison of efficacy of visual inspection with 4% acetic acid, visual inspection with Lugol's iodine, Pap smear and colposcopy in screening cervical precancerous lesions

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    Background: Cervical malignancy is the fourth most common cancer in women worldwide. Screening of high-grade cervical intraepithelial neoplasia aids in early detection and their effective treatment which constitutes the most effective and widely used strategy to prevent cervical carcinoma throughout the world. Objectives of the study were to: screen women with visual inspection with 4% acetic acid (VIA), visual inspection with Lugol's iodine (VILI), Pap smear and colposcopy who have abnormal symptoms for unhealthy cervix; and to evaluate the sensitivity and specificity of VIA, VILI, Pap smear and colposcopy.Methods: This was a hospital based cross sectional study conducted at Jorhat Medical College, Assam at the department of obstetrics and gynaecology from June 2020 to May 2021, carried out on 60 women. This study was done on 60 women who fulfilled the inclusion and exclusion criteria, were first subjected to Pap smear followed by VIA, VILI, colposcopy and biopsy for confirmation of lesion, if needed. Data was obtained and statistically analyzed.Results: VIA showed sensitivity 96.15%, specificity 62.50% and diagnostic accuracy 88.23%. VILI showed sensitivity 89.65%, specificity 40% and diagnostic accuracy 82.35%. Colposcopy showed sensitivity 96.66%, specificity 25% and diagnostic accuracy 88.23%. Pap smear showed sensitivity of 86.66%, specificity 75% and diagnostic accuracy of 85.29%.Conclusions: Our study shows that VIA, VILI, Pap smear and colposcopy has comparable sensitivity. Pap smear shows better specificity. Therefore, use of combination of these tests gives better sensitivity and specificity for early detection of cervical carcinoma.

    Covalent bonding and the nature of band gaps in some half-Heusler compounds

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    Half-Heusler compounds \textit{XYZ}, also called semi-Heusler compounds, crystallize in the MgAgAs structure, in the space group F4ˉ3mF\bar43m. We report a systematic examination of band gaps and the nature (covalent or ionic) of bonding in semiconducting 8- and 18- electron half-Heusler compounds through first-principles density functional calculations. We find the most appropriate description of these compounds from the viewpoint of electronic structures is one of a \textit{YZ} zinc blende lattice stuffed by the \textit{X} ion. Simple valence rules are obeyed for bonding in the 8-electron compound. For example, LiMgN can be written Li+^+ + (MgN)^-, and (MgN)^-, which is isoelectronic with (SiSi), forms a zinc blende lattice. The 18-electron compounds can similarly be considered as obeying valence rules. A semiconductor such as TiCoSb can be written Ti4+^{4+} + (CoSb)4^{4-}; the latter unit is isoelectronic and isostructural with zinc-blende GaSb. For both the 8- and 18-electron compounds, when \textit{X} is fixed as some electropositive cation, the computed band gap varies approximately as the difference in Pauling electronegativities of \textit{Y} and \textit{Z}. What is particularly exciting is that this simple idea of a covalently bonded \textit{YZ} lattice can also be extended to the very important \textit{magnetic} half-Heusler phases; we describe these as valence compounds \textit{ie.} possessing a band gap at the Fermi energy albeit only in one spin direction. The \textit{local} moment in these magnetic compounds resides on the \textit{X} site.Comment: 18 pages and 14 figures (many in color

    Hyperinsulinism in short-chain L-3-hydroxyacyl-CoA dehydrogenase deficiency reveals the importance of beta-oxidation in insulin secretion

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    A female infant of nonconsanguineous Indian parents presented at 4 months with a hypoglycemic convulsion. Further episodes of hypoketotic hypoglycemia were associated with inappropriately elevated plasma insulin concentrations. However, unlike other children with hyperinsulinism, this patient had a persistently elevated blood spot hydroxybutyrylcarnitine concentration when fed, as well as when fasted. Measurement of the activity of L-3-hydroxyacyl-CoA dehydrogenase in cultured skin fibroblasts with acetoacetyl-CoA substrate showed reduced activity. In fibroblast mitochondria, the activity was less than 5% that of controls. Sequencing of the short-chain L-3-hydroxyacyl-CoA dehydrogenase (SCHAD) genomic DNA from the fibroblasts showed a homozygous mutation (C773T) changing proline to leucine at amino acid 258. Analysis of blood from the parents showed they were heterozygous for this mutation. Western blot studies showed undetectable levels of immunoreactive SCHAD protein in the child's fibroblasts. Expression studies showed that the P258L enzyme had no catalytic activity. We conclude that C773T is a disease-causing SCHAD mutation. This is the first defect in fatty acid beta -oxidation that has been associated with hyperinsulinism and raises interesting questions about the ways in which changes in fatty acid and ketone body metabolism modulate insulin secretion by the beta cell. The patient's hyperinsulinism was easily controlled with diazoxide and chlorothiazide

    Mature Care and Nursing in Psychiatry: Notions Regarding Reciprocity in Asymmetric Professional Relationships

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    The idea behind this article is to discuss the importance and to develop the concept of reciprocity in asymmetric professional relationships. As an empirical starting point for an examination of the possible forms of reciprocity between patients and nurses in psychiatry, we chose two qualitative in-depth interviews with two different patients. The manners in which these two patients relate to medical personnel—one is dependent, the other is independent—show that this presents challenges to nurses. The theoretical context is provided by the notion of mature care as it has been developed by feminist-oriented ethics of care, in contrast to the notion of altruistic care. In relation to the concept of mature care, we discuss how nursing can be perceived in demanding relationships with patients in psychiatry. Reciprocity implies that, in principle, the interests of the nurses also matter in a nurse-patient relationship. We show that reciprocity—in practice—is complicated and challenging in a number of different ways. Mature care—with its systematic inclusion of relationships and reciprocity—provides an alternative understanding of what takes place between patients and nurses compared with an altruistic notion of care. As such, mature care can be regarded as an useful paradigm for nurse-patient relationships in psychiatry

    Oncogenic viruses associated with vulva cancer in HIV-1 patients in Botswana

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    BACKGROUND: Oncoviruses such as HPV, KSHV, and EBV have been reported in patients with HIV infection and AIDS. How oncovirus-associated cancers rise in AIDS patients has not been fully established. The purpose of our study was to identify the viral agents in vulvar cancer and to assess their contribution to pathogenesis. METHOD: We retrospectively identified a total of 13 vulva tissue samples from HIV-1 positive and 9 vulvar samples from HIV-1 negative patients from the Botswana National Health Laboratory in Gaborone, Botswana, a Southern African country with a high incidence of HIV. We utilized PCR and IHC to identify HPV, EBV, KSHV, and JC virus in FFPE preserved tissue samples. RESULTS: Using the GP5(+)/GP6(+) primer set we detected several HPV types in tissue samples. EBV was detected in all of the positive cases (100%) and in most of the negative cases (89%). KSHV was detected in 39% of the HIV-1 positive samples and in 11% of the negative samples, and no JC virus was detected in any of the samples. Using IHC we demonstrated that LANA was expressed in 61% of the positive samples and in 44% of the negative samples. The ubiquitous EBV was more consistently expressed in negative cases (100%) than in positive cases (69%). Interestingly, the HPV-16 E6 transcript was detected in 56% of the negative samples compared to 31% of the positive samples. However, the cell cycle protein P21 used as a surrogate marker for HPV was detected in 77% of the positive samples and in 44% of the negative samples, while VEGF signals were similar in both positive (92%) and negative samples (89%). CONCLUSION: Our study, suggests that in Botswana, vulvar squamous cell carcinoma (VSCC) is associated with oncogenic viruses present in the niche but the contribution and progression may be regulated by HPV and other immunosuppressive infections that include HIV-1

    Electronic structure, magnetism, and disorder in the Heusler compound Co2_2TiSn

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    Polycrystalline samples of the half-metallic ferromagnet Heusler compound Co2_2TiSn have been prepared and studied using bulk techniques (X-ray diffraction and magnetization) as well as local probes (119^{119}Sn M\"ossbauer spectroscopy and 59^{59}Co nuclear magnetic resonance spectroscopy) in order to determine how disorder affects half-metallic behavior and also, to establish the joint use of M\"ossbauer and NMR spectroscopies as a quantitative probe of local ion ordering in these compounds. Additionally, density functional electronic structure calculations on ordered and partially disordered Co2_2TiSn compounds have been carried out at a number of different levels of theory in order to simultaneously understand how the particular choice of DFT scheme as well as disorder affect the computed magnetization. Our studies suggest that a sample which seems well-ordered by X-ray diffraction and magnetization measurements can possess up to 10% of antisite (Co/Ti) disordering. Computations similarly suggest that even 12.5% antisite Co/Ti disorder does not destroy the half-metallic character of this material. However, the use of an appropriate level of non-local DFT is crucial.Comment: 11 pages and 5 figure
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