132 research outputs found

    Experimental Study of a Beta Stirling Thermal Machine Type Functioning in Receiver and Engine Modes

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    In this paper we studied a beta type Stirling machine. At first, we present the adopted theoretical quasi-stationary model. Then, we pass to the physical and geometrical presentation of this machine. The Latter was experimented according to two configurations: motor configuration and receiver configuration. For the first configuration, in order to improve the performances of the machine, we proceeded to the insulation of the machine hot room to reduce losses by radiation. For the second configuration, the machine is experimented as a heat pump and refrigerator. Comparisons between the theoretical and experimental results are also presented. We finally validated the results obtained by the model with experiments

    A rare case of acute lymphoblastic leukemia in a patient with light chain (AL) amyloidosis treated with lenalidomide.

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    Lenalidomide belongs to a novel class of drugs called Immunomodulators which are now being used for the treatment of plasma cell dyscrasias with variable degrees of efficacy and toxicity. Though Second Primary Malignancies (SPM) have been a concern with its use, the benefits of the treatment outweigh the risks. The leukemogenic risk seems to be potentiated especially when combined with alkylating agents and the SPMs documented are predominantly myeloblastic. To date there are no reported cases of new lymphocytic leukemias in AL amyloidosis, regardless of whether undergone treatment or not. We present a case of AL amylodosis who was treated with lenalidomide and subsequently developed acute lymphoblastic leukemia

    Percentage of {Gamma}{Delta} T Cells in Panniculitis by Paraffin Immunohistochemical Analysis.

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    Cutaneous T-cell lymphomas with panniculitis-like histologic features have different clinical courses depending on whether they are composed of alphabeta T cells or gammadelta T cells, necessitating their distinction for proper prognostication. However, unlike alphabeta T cells, gammadelta T cells cannot be reliably detected in formalin-fixed, paraffin-embedded sections. We demonstrated that a commercially available antibody can detect gammadelta T cells and examined 2 cases of flow cytometry-proven gammadelta T-cell lymphomas and 15 control cases of nonneoplastic panniculitis. In both lymphomas, the atypical lymphocytes were gammadelta T cells, whereas the reactive lymphocytes were alphabeta T cells. In contrast, nonneoplastic panniculitis had predominantly alphabeta T cells with many fewer and individually scattered gammadelta T cells. The detection of gammadelta T cells in paraffin sections provides a powerful new tool to characterize T cells in lymphomas and inflammation

    Progressive optic neuropathy in congenital glaucoma associated with the Sirsasana yoga posture

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    The authors describe a case of progressive optic neuropathy in a patient with congenital glaucoma who had routinely practiced the Sirsasana (headstand) yoga posture for several years. Ophthalmic examination included best-corrected visual acuity, anterior segment examination, indirect oplithalmoscopy, ultrasound pachymetry for central corneal thickness, and intraocular pressure before, during, and after maintaining the Sirsasana posture for 5 minutes. Intraocular pressure increased significantly during the Sirsasana posture. Transient elevation in intraocular pressure during yoga exercises may lead to progressive glaucomatous optic neuropathy, especially in susceptible patients with congenital glaucoma

    Mortality, Recruitment and Change of Desert Tree Populations in a Hyper-Arid Environment

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    BACKGROUND: Long-term vegetation changes in hyper-arid areas have long been neglected. Mortality, recruitment and change in populations of the ecologically and culturally important and drought persistent Acacia tortilis and Balanites aegyptiaca are therefore estimated in the Eastern Desert of Egypt, and are related to the primary agents of change, water conditions and human intervention. METHODOLOGY: A change analysis using high-resolution Corona images (1965) in combination with field data (2003) is the basis for recruitment, mortality and change estimates. For assessing the influence of water conditions on patterns in recruitment and survival, different types of generalized linear models are tested. CONCLUSIONS: The overall trend in population size in that part of the Eastern Desert studied here is negative. At some sites this negative trend is alarming, because the reduction in mature trees is substantial (>50%) at the same time as recruitment is nearly absent. At a few sites there is a positive trend and better recruitment. Frequent observations of sprouting in saplings indicate that this is an important mechanism to increase their persistence. It is the establishment itself that seems to be the main challenge in the recruitment process. There are indications that hydrological variables and surface water in particular can explain some of the observed pattern in mortality, but our results indicate that direct human intervention, i.e., charcoal production, is the main cause of tree mortality in the Eastern Desert

    Free-standing polyelectrolyte membranes made of chitosan and alginate

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    Free-standing films have increasing applications in the biomedical field as drug delivery systems for wound healing and tissue engineering. Here, we prepared free-standing membranes by the layer-by-layer assembly of chitosan and alginate, two widely used biomaterials. Our aim was to produce a thick membrane and to study the permeation of model drugs and the adhesion of muscle cells. We first defined the optimal growth conditions in terms of pH and alginate concentration. The membranes could be easily detached from polystyrene or polypropylene substrate without any postprocessing step. The dry thickness was varied over a large range from 4 to 35 ΞΌm. A 2-fold swelling was observed by confocal microscopy when they were immersed in PBS. In addition, we quantified the permeation of model drugs (fluorescent dextrans) through the free-standing membrane, which depended on the dextran molecular weight. Finally, we showed that myoblast cells exhibited a preferential adhesion on the alginate-ending membrane as compared to the chitosan-ending membrane or to the substrate side.This work was financially supported by Foundation for Science and Technology (FCT) through the Scholarship SFRH/BD/64601/2009 granted to S.G.C. C.M. is indebted to Grenoble INP for financial support via a postdoctoral fellowship. This work was supported by the European Commission (FP7 Program) via a European Research Council starting grant (BIOMIM, GA 259370 to C.P.). C.P. is also grateful to Institut Universitaire de France and to Grenoble Institute of Technology for financial support. We thank Isabelle Paintrand for her technical help with the confocal apparatus and Patrick Chaudouet for his help with SEM imaging

    Understanding renal posttransplantation anemia in the pediatric population

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    Advances in renal transplantation management have proven to be beneficial in improving graft and patient survival. One of the properties of a well-functioning renal allograft is the secretion of adequate amounts of the hormone erythropoietin to stimulate erythropoiesis. Posttransplantation anemia (PTA) may occur at any point in time following transplantation, and the cause is multifactoral. Much of our understanding of PTA is based on studies of adult transplant recipients. The limited number of studies that have been reported on pediatric renal transplant patients appear to indicate that PTA is prevalent in this patient population. Erythropoietin deficiency or resistance is commonly associated with iron deficiency. An understanding of the risk factors, pathophysiology and management of PTA in the pediatric renal transplant population may provide guidelines for clinicians and researchers in the pursuit of larger prospective randomized control studies aimed at improving our limited knowledge of PTA. Recognition of PTA through regular screening and evaluation of the multiple factors that may contribute to its development are recommended after transplantation
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