346 research outputs found
Characterization of injection system by time-frequency analysis
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
From an imagined community to genuine communities: Birth and development of Etrimo Apartment Buildings in Brussels, 1950–2020
Using an analysis of apartment buildings built in Brussels by the real estate developer Etrimo between 1950 and 1970, we investigate the ability of collective housing to build and support an inhabitants’ community.
After World War II, Etrimo took advantage of the poor state of existing housing stock and the return of Belgian families from Congo to intensify its production of apartment buildings for aspiring middle-class homeowners. These buildings consisted of repeated, identical three-room dwellings offering all modern comforts for the nuclear family of the thirty-year post-war boom. The portrait of this family, reflected in various commercial brochures and the 14,000 dwellings built in Brussels by the private developer, suggests a relatively homogeneous middle class. How did this imagined, abstract community materialise?
First, we present how the juxtaposition of identical households may or may not have produced a homogenous community at the project’s different spatial scales. This analysis is based on primary sources at our disposal: sales brochures, Etrimo advertisement posters, writings by the company’s founder Jean-François Collin on the legal and financial set-up of his business, plans of the housing units and complexes.
Second, on the basis of interviews with inhabitants and on-site observations of living practices in the collective spaces of the housing estates, we highlight the model Etrimo housing estates offers contemporary society for new ways of living together
Wavelet Analysis of the Turbulent LES Data of the Lid-Driven Cavity Flow
International audienceBoth Fourier and wavelet transforms are performed on data obtained from large-eddy simulations of the turbulent flow in a lid-driven cubical cavity. The analyzed data or synthetic signals are picked at three specific points inside the cavity allowing to investigate three regimes over time: laminar, transitional and turbulent. The main objective of this study is to generate and analyze synthetic signals in order to confirm the correlation between the computed physical quantities and those expected theoretically
On the relationship between proteinuria and plasma phosphate.
Albuminuria is strongly associated with renal and cardiovascular outcomes independently of renal function level. However, the pathophysiology of these associations is debated. In chronic kidney disease (CKD), phosphate retention participates in cardiovascular events and increased cardiovascular mortality. We hypothesised that albuminuria may modulate tubular phosphate handling by the kidney. To verify this hypothesis, we first studied the association between phosphataemia and albuminuria in children with nephrotic syndrome and in adults with CKD. In both cases, higher albuminuria was associated with higher phosphate level, independently of glomerular filtration rate. We further tried to decipher the molecular mechanisms of these observations. Using animal models of nephrotic proteinuria, we could show that albuminuric rats and mice had abnormally elevated sodium-phosphate apical co-transporter expression, despite elevated fibroblast growth factor 23 (FGF23). The FGF23 downstream pathway was inhibited despite elevated FGF23 levels. Klotho protein expression was also lower in proteinuric animals compared to controls. Finally, albumin had no direct effects on phosphate transport in cells. Altogether, we show that albuminuria induces alteration of phosphate tubular handling, independently of glomerular filtration rate. The mechanisms involved appear to include Klotho down-regulation and resistance to FGF23. This observation may link albuminuria to increased cardiovascular disease via altered phosphate handling. Finally, this observation opens up further opportunities to better understand the link between albuminuria, Klotho, FGF23 and phosphate handling
De la norme comme garantie imposée aux appropriations comme initiatives raisonnées
International audienceL’héritage de Francfort s’est traduit par des « ratios » (E. May) qui ont permis de garantir, dans la production moderne du logement, des conditions d’habitabilité à un nombre massif de logements urbains. Cependant, les normes qui en ont résulté sont plus tard devenues un possible carcan, dans un monde gagné par les promesses de la société de consommation et l’émergence de l’individualisme. Dans la seconde moitié du XXe siècle, la taille des logements a tendu à se réduire en même temps que l’évolution des modes de vie faisait naître de nouvelles attentes qui s’expriment dans des formes d’appropriations diverses. Partant de nos travaux sur le logement social et la maison individuelle, conduits dans différentes métropoles françaises, portugaises, et marocaines, qui confrontent (à partir de relevés habités et d’entretiens) les pratiques, les représentations et les aspirations des habitants aux lieux architecturaux et urbains dans lesquelles elles évoluent, nous présenterons les dépassements de la norme que constituent l’appropriation du logement standard octroyé. Ces appropriations s’expriment à travers: _des modifications, mineures ou majeures, parfois « hors normes », voire illégales en regard des normes autorisées, _ l’introduction, souvent subtile, d’équipements ou de mobiliers, ajoutant - preuve de la capacité d’initiative de l’habitant - des qualités complémentaires à l’espace initial, qu’il soit contraint ou choisi
Lattice Boltzmann Method for Mathematical Morphology: Application to Porous Media
International audienceThe LBM (Lattice Boltzmann Method) is often used in CFD (Computational Fluid Dynamics) for efficient fluid flow simulations. Computation of the permeability of a porous media from direct simulations is a common application which benefits from the ability of the LBM (Lattice Boltzmann Method) to embed porosity parameters. The MM (Mathematical Morphology) is widely used in image processing as the theoretical aspects guaranty robust algorithms for geometrical characterization of shapes appearing in images. The MM is commonly used to compute porosity from porous media images. The union of these two methods has been recently done through the LB3M (Lattice Boltzmann Method for Mathematical Morphology). The present work extends the LB3M to the extraction of porosity and pores segmentation from images. In order to benefit from the full capacity of the LB3M, it is necessary to reformulate and adjust the algorithms in a new paradigm. Thus, the underlying concept and algorithms required for computing the different previous information are detailed. Moreover, a comparison is provided between the permeability resulting from the CFD and MM both implemented by using the LBM. To sum up, this work emphasizes the full capacity of the LB3M to obtain complex transformations and operations issued from the MM theory through completely new and innovative algorithms. The herein challenge is to highlight the abilities of the LB3M to match with physical phenomenons. Indeed, the LB3M keeps the advantages from the MM such as a complete theory, fast convergence, scalability, robustness, etc. while adding the power of the LBM: statistical physics origins, partial differential equation solver, intrinsic properties of parallelization, efficiency, etc
Update on vitamin D and evaluation of vitamin D status.
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
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
A New Human NHERF1 Mutation Decreases Renal Phosphate Transporter NPT2a Expression by a PTH-Independent Mechanism
Background: The sodium-hydrogen exchanger regulatory factor 1 (NHERF1) binds to the main renal phosphate transporter NPT2a and to the parathyroid hormone (PTH) receptor. We have recently identified mutations in NHERF1 that decrease renal phosphate reabsorption by increasing PTH-induced cAMP production in the renal proximal tubule. Methods: We compared relevant parameters of phosphate homeostasis in a patient with a previously undescribed mutation in NHERF1 and in control subjects. We expressed the mutant NHERF1 protein in Xenopus Oocytes and in cultured cells to study its effects on phosphate transport and PTH-induced cAMP production. Results: We identified in a patient with inappropriate renal phosphate reabsorption a previously unidentified mutation (E68A) located in the PDZ1 domain of NHERF1.We report the consequences of this mutation on NHERF1 function. E68A mutation did not modify cAMP production in the patient. PTH-induced cAMP synthesis and PKC activity were not altered by E68A mutation in renal cells in culture. In contrast to wild-type NHERF1, expression of the E68A mutant in Xenopus oocytes and in human cells failed to increase phosphate transport. Pull down experiments showed that E68A mutant did not interact with NPT2a, which robustly interacted with wild type NHERF1 and previously identified mutants. Biotinylation studies revealed that E68A mutant was unable to increase cell surface expression of NPT2a. Conclusions: Our results indicate that the PDZ1 domain is critical for NHERF1- NPT2a interaction in humans and for th
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