2,237 research outputs found

    Nonlinear transient analysis via energy minimization

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    The formulation basis for nonlinear transient analysis of finite element models of structures using energy minimization is provided. Geometric and material nonlinearities are included. The development is restricted to simple one and two dimensional finite elements which are regarded as being the basic elements for modeling full aircraft-like structures under crash conditions. The results indicate the effectiveness of the technique as a viable tool for this purpose

    Efficiency of unconstrained minimization techniques in nonlinear analysis

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    Unconstrained minimization algorithms have been critically evaluated for their effectiveness in solving structural problems involving geometric and material nonlinearities. The algorithms have been categorized as being zeroth, first, or second order depending upon the highest derivative of the function required by the algorithm. The sensitivity of these algorithms to the accuracy of derivatives clearly suggests using analytically derived gradients instead of finite difference approximations. The use of analytic gradients results in better control of the number of minimizations required for convergence to the exact solution

    Enhancement of the Power Output of Photogalvanic Cells

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    Evaluation of the effects of Aegle marmelos and Punica granatum in an experimental model of gastrointestinal barrier dysfunction

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    Background: The study was conducted to evaluate the effects of Aegle marmelos and Punica granatum in an experimental model of gastrointestinal barrier dysfunction induced by common bile duct ligation.Methods: Institutional animal ethics committee approval was obtained. Forty two Wistar rats (either sex, 150-250 gms) divided into seven groups (n=six/group), were subjected to sham operation (group 1) or bile duct ligation (groups 2-7) and treated with distilled water (groups 1 and 2); 0.75mg/kg glutamine (group 3); 0.27 g/kg and 0.54 g/kg of A. marmelos (groups 4 and 5); 3.6 g/kg and 7.2 g/kg P. granatum (groups 6 and 7) orally once daily for 10 days. On Day 11, animals were sacrificed and samples of the jejunum, ileum and mesenteric lymph nodes were obtained to study jejunal and ileal villous morphology, villous heights, jejunal mucosal sucrase enzyme activity and bacterial translocation to mesenteric lymph nodes.Results: Glutamine prevented blunting of the intestinal villi, bacterial translocation and a fall in the sucrase enzyme activity. Both the plant drugs prevented blunting of the villi (except low dose A. marmelos for ileal villi) and a fall in the villous heights (except low dose P. granatum for jejunal villi), decreased the bacterial translocation (except low dose A. marmelos), and prevented a fall in the sucrase enzyme activity when compared to the disease control. The high doses of both A. marmelos and P. granatum were comparable to glutamine for all the variables tested.Conclusions: Both A. marmelos and P. granatum maintained the gastrointestinal barrier function in this model

    Role of imprint cytology in gastrointestinal tract: A study

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    Touch imprint cytology is the science of interpretation of cells that are either exfoliated from epithelial surfaces or removed from various tissues. Over the years cytology has evolved into a major branch in diagnostic pathology. It includes both exfoliative cytology and fine needle aspiration biopsy. Exfoliative cytology has advanced to become the most reliable screening test for uterine cervical malignancies. It also finds its application in various other organ systems, either as a part of analysis of body fluid, lavage fluid, abrasive technique such as brushings and scrapings or the simple touch or imprint smears. Dudgeon and Patrick in 1927 and Bamforth and Osborn in 1958 have reported about imprint technique. Touch imprint cytology has been found valuable in the diagnosis of lesions of gastrointestinal tract, central nervous system, lung, thyroid, parathyroid, breast, ovary, lymph node, spleen, bone marrow, bone and soft tissue, oral cavity, pancreaticobiliary system. The application of video endoscopy has greatly facilitated the diagnosis of gastrointestinal tract lesions. Though taking biopsies has been common practice in endoscopic diagnosis, touch imprint cytology has not been widely practiced in this setting. This is in spite of several studies which have proved the usefulness of cytology beyond doubt. Many workers find the technique practical in giving an autopsy diagnosis especially because of its cost effectiveness. It can be used as a teaching tool for students of autopsy pathology due to its simplicity. With this background, we designed a study to investigate the role of imprint cytology in the endoscopic and intraoperative diagnosis of lesions of gastrointestinal tract and pancreaticobiliary system in our institute

    Do health systems delay the treatment of poor children? A qualitative study of child deaths in rural Tanzania.

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    Child mortality remains one of the major public-health problems in Tanzania. Delays in receiving and accessing adequate care contribute to these high rates. The literature on public health often focuses on the role of mothers in delaying treatment, suggesting that they contact the health system too late and that they prefer to treat their children at home, a perspective often echoed by health workers. Using the three-delay methodology, this study focus on the third phase of the model, exploring the delays experienced in receiving adequate care when mothers with a sick child contact a health-care facility. The overall objective is to analyse specific structural factors embedded in everyday practices at health facilities in a district in Tanzania which cause delays in the treatment of poor children and to discuss possible changes to institutions and social technologies. The study is based on qualitative fieldwork, including in-depth interviews with sixteen mothers who have lost a child, case studies in which patients were followed through the health system, and observations of more than a hundred consultations at all three levels of the health-care system. Data analysis took the form of thematic analysis. Focusing on the third phase of the three-delay model, four main obstacles have been identified: confusions over payment, inadequate referral systems, the inefficient organization of health services and the culture of communication. These impediments strike the poorest segment of the mothers particularly hard. It is argued that these delaying factors function as 'technologies of social exclusion', as they are embedded in the everyday practices of the health facilities in systematic ways. The interviews, case studies and observations show that it is especially families with low social and cultural capital that experience delays after having contacted the health-care system. Reductions of the various types of uncertainty concerning payment, improved referral practices and improved communication between health staff and patients would reduce some of the delays within health facilities, which might feedback positively into the other two phases of delay
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