58 research outputs found

    Characterization of injection system by time-frequency analysis

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    The aim of this study is to provide a better understanding while the injectio n system of Diesel engine is running, by measuring the forward movement of the nozzle inside a testing fence system . As a matter of fact, one use non parametric methods of signal processing are used, such as the Wigner– Ville representation, the Unterberger representation, and the scalogram representation which is the wavelet transform square modulus . Results are comparated with the theoritical calculus.Le but de cette étude est d'apporter une meilleure compréhension du fonctionnement des systèmes d'injection montés sur moteur Diesel, en mesurant l'avancement du jet d'injecteurs montés dans une enceinte test. En fait, on utilise des méthodes non paramétriques du traitement du signal, telles que la représentation de Wigner-Ville, la représentation due à Unterberger, et le scalogramme module carré de la transformée en ondelette. Les résultats sont comparés avec le calcul théorique

    Update on vitamin D and evaluation of vitamin D status.

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    Knowledge about vitamin D has greatly improved during the last few years. Vitamin D cannot any more be considered as exclusively necessary to prevent ricket/osteomalacia. Its role in the prevention of some osteoporotic fractures in the elderly (in association with calcium nutrition) is now well demonstrated and many epidemiologic and laboratory data argue for a role in the prevention of several diseases or anomalies (cancer, auto-immune diseases, cardiovascular events, sarcopenia...). A few intervention studies confirming some of these effects also exist. Vitamin D status can easily be assessed by measuring serum 25 hydroxy vitamin D (25OHD) level. However, many experts have claimed that the population-based reference values for 25OHD are too low and that the cut-off value below which vitamin D insufficiency can be present is somewhere between 20 and 40ng/mL with a clear tendency to target values above 30ng/mL (75nmol/L). The main consequences are that vitamin D insufficiency is highly frequent whereas the currently recommended supplementation doses are not sufficient

    Parafoveal OCT Angiography Features in Diabetic Patients without Clinical Diabetic Retinopathy: A Qualitative and Quantitative Analysis

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    Purpose. To evaluate the capacity of OCT angiography (OCTA) for detecting infraclinical lesions in parafoveal capillaries in diabetic patients without diabetic retinopathy (DR). Methods. This prospective observational cross-sectional case-control study analyzed the superficial and deep capillary plexuses (SCP and DCP) on macular OCTA scans (3 × 3 mm) centered on the fovea. We compared 22 diabetic patients (34 eyes included) without DR diagnosis on color fundus photographs, with 22 age- and gender-matched nondiabetic controls (40 eyes included). Qualitative analysis concerned morphological ischemic capillary alterations. Quantitative analysis measured foveal avascular zone (FAZ) size, parafoveal capillary density, and enlargement coefficient of FAZ between SCP and DCP. Results. Neither the qualitative nor quantitative parameters were significantly different between both groups. No microaneurysms or venous tortuosity was observed in any of the analyzed images. On the SCP, the mean FAZ area was 0.322 ± 0.125 mm2 in diabetic patients and 0.285 ± 0.150 mm2 in controls, P=0.31. On the DCP, the mean FAZ area was 0.444 ± 0.153 mm2 in cases and 0.398 ± 0.138 mm2 in controls, P=0.20. Conclusion. OCTA did not detect infraclinical qualitative or quantitative differences in parafoveal capillaries of diabetic patients without DR in comparison with nondiabetic controls

    Multi-objective optimization of gate location and processing conditions in injection molding using MOEAs: experimental assessment

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    The definition of the gate location in injection molding is one of the most important factors in achieving dimensionally accuracy of the parts. This paper presents an optimization methodology for addressing this problem based on a Multi-objective Evolutionary Algorithm (MOEA). The algorithm adopted here is named Reduced Pareto Set Genetic Algorithm (RPSGA) and was used to create a balanced filling pattern using weld line characterization. The optimization approach proposed in this paper is an integration of evolutionary algorithms with Computer-Aided Engineering (CAE) software (Autodesk Moldflow Plastics software). The performance of the proposed optimization methodology was illustrated with an example consisting in the injection of a rectangular part with a non-symmetrical hole. The numerical results were experimentally assessed. Physical meaning was obtained which guaranteed a successful process optimization.This work was supported by the Portuguese Fundação para a Ciência e Tecnologia under grant SFRH/BD/28479/2006 and IPC/I3N – Institute for Polymers and Composites, University of Minho.info:eu-repo/semantics/publishedVersio

    Localization and function of the renal calcium-sensing receptor

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    The ability to monitor changes in the ionic composition of the extracellular environment is a crucial feature that has evolved in all living organisms. The cloning and characterization of the extracellular calcium-sensing receptor (CaSR) from the mammalian parathyroid gland in the early 1990s provided the first description of a cellular, ion-sensing mechanism. This finding demonstrated how cells can detect small, physiological variations in free ionized calcium (Ca 2+) in the extracellular fluid and subsequently evoke an appropriate biological response by altering the secretion of parathyroid hormone (PTH) that acts on PTH receptors expressed in target tissues, including the kidney, intestine, and bone. Aberrant Ca 2+ sensing by the parathyroid glands, as a result of altered CaSR expression or function, is associated with impaired divalent cation homeostasis. CaSR activators that mimic the effects of Ca 2+ (calcimimetics) have been designed to treat hyperparathyroidism, and CaSR antagonists (calcilytics) are in development for the treatment of hypercalciuric disorders. The kidney expresses a CaSR that might directly contribute to the regulation of many aspects of renal function in a PTH-independent manner. This Review discusses the roles of the renal CaSR and the potential impact of pharmacological modulation of the CaSR on renal function

    Transformee bilineaires temps : Echelle des signaux asymptotioues d'energie finie

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    La distribution bilinéaire temps échelle Bz(t,η) due à A.GROSSMANN s'inscrit dans le cadre des représentations bilinéaires affine dues à P.FLANDRIN et O.RIOUL. Les principales propriétés de Bz(t,η) sont ici énoncées. Cet article propose ensuite une méthode de calcul de Bz(t,η) pour des signaux asymptotiques d'énergie finie. Les termes d'interférence "internes" et "externes" inhérent à cette distribution temps échelle sont analysés

    The symmetric logarithmic image processing model

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    International audienceIn this paper, a new extension of logarithmic image processing (LIP) model, called Symmetric Logarithmic Image Processing (SLIP), is proposed. Inspired by the previously developed symmetric models, the SLIP model defines a vector space on a symmetric bounded set. The development is aimed at (1) maintaining the physical interpretation of the LIP model and (2) solving the potential out-of-range problem which the LIP model has. The SLIP model is also able to deal with transmitted and reflected light images. The advantage of the SLIP is demonstrated through an image enhancement application using the generalized unsharp masking algorithm

    Interpretation physique des representations bilineaires temps : Echelle et des representations frequence -echelle

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    Les distributions temps échelle, ou WIGNER VILLE affines, possèdent une transformée de FOURIER à deux dimensions fréquence échelle (Ο,ξ). La variable Ç s'interprète comme une date réduite. Possédant la symétrie hermitique la transformée de FOURIER est bornée à l'origine en module en étant liée à la fonction d'Ambiguïté symétrique de VILLE-SUSSMANN. Cette grandeur, modifiée par la transformation linéaire due à P. FLANDRIN, fournit par transformation de MELLIN FOURIER la classe hyperbolique des représentations (temps, fréquence). Les résultats manifestent des règles d'écriture symétrisée ou non de l'opérateur de changement d'échelle

    A Way Towards Optimization of Injection Molding

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