Localization for Schrodinger operators with random vector potentials

We prove Anderson localization at the internal band-edges for periodic magnetic Schr{\"o}dinger operators perturbed by random vector potentials of Anderson-type. This is achieved by combining new results on the Lifshitz tails behavior of the integrated density of states for random magnetic Schr{\"o}dinger operators, thereby providing the initial length-scale estimate, and a Wegner estimate, for such models

High Saturated Fat-Enriched Diet Evokes Endoplasmic Reticulum Stress and Consequently Increases ?- Site App Cleaving Enzyme 1 Activity in Amyloid-Beta Engenderment in the Brain

Alzheimer’s disease (AD) is the most common form of dementia in the elderly that is histo-pathologically characterized by extracellular accumulation of aggregated Amyloid-? (A?) peptide as neuritic senile plaques and the intracellular accumulation of aggregated hyperphosphorylated protein tau (?) as neurofibrillary tangles. The aspartyl protease BACE1 is indispensable for the engenderment of A? and catalyzes the rate-limiting step in A? genesis from A?PP. The expression of BACE1 protein as well as its enzymatic activity is significantly augmented in the AD brain. The etiology of AD is multifactorial and egregiously comprehended, but epidemiological studies have implicated a diet rich in saturated free fatty acids (sFFA) as a significant risk factor for developing AD. Palmitic acid (palmitate) is the most abundant long-chain free saturated fatty acid in the brain and the diet and higher palmitate levels in the plasma, as observed in obesity and diabetes, inversely correlate with cognitive function. Recent cogent evidence has implicated endoplasmic reticulum (ER) stress as one of the culpable factors in initiating and fostering the deleterious neurodegenerative changes in AD. A multitude of studies have cogently demonstrated that sFFA such as palmitic acid evoke ER stress. In this study we demonstrate that palmitate evokes ER stress leading to the induction of CHOP expression which indispensably mediates the up-regulation in BACE1 expression and A? engenderment via the NF-?B signaling pathway. Our study unveils a novel ER stress/CHOP/NF-?B signaling pathway and delineates the molecular mechanism thereof that mediate the palmitate-induced up-regulation of BACE1 expression

Endoplasmic Renticulum-Activated C/EBP Homologous Protein Mediates the Palmitate-Enriched Diet Induced Increase in the Lipogenic Expression in the Liver

Non-alcoholic fatty liver disease (NAFLD) is a wide spectrum pathophysiological disorder characterized by insulin resistance, hepatic steatosis, and inflammation. Diets rich in saturated fat are known to evoke insulin resistance, ER stress, and de novo lipogenesis and thereby contribute to the pathogenic mechanisms involved in NAFLD. Palmitic acid (palmitate) is the most abundant saturated fatty acid in the diet and palmitate-enriched diets are known to cause NAFLD in a multitude of rodent models of NAFLD. Palmitate-enriched diets are known to induce steatosis by inducing the expression of genes involved in de novo lipogenesis. However, the signaling mechanisms and the downstream molecular mediators involved have not been elucidated. In this study, we explored the role of palmitate-induced ER stress and subsequent induction of C/EBP Homologous Protein (CHOP) expression in the modulation of expression and transcriptional activities of Liver X Receptor alpha (LXR?) and Sterol Response Element Binding Protein 1c (SREBP1c), two indispensable transcription factors and master regulators of genes involved in de novo lipogenesis. We demonstrate, in exogenous palmitate-treated HepG2 cells and in the livers of palmitate-enriched diet-fed mice, that palmitate evokes ER stress leading to the induction of CHOP expression. We further show that CHOP mediates the up-regulation in expression levels and transcriptional activities of LXR? and SREBP1c. Our study identifies a unique ER stress-CHOP-LXR?/SREBP1c signaling pathway that mediates palmitate-induced up-regulation of lipogenic gene expression in the liver that may play a critical role in the etiopathogenesis of NAFLD

Enhancement of Bacillus subtilis Lipopeptide Biosurfactants Production through Optimization of Medium Composition and Adequate Control of Aeration

Interest in biosurfactants has increased considerably in recent years, as they are potentially used in many commercial applications in petroleum, pharmaceuticals, biomedical, and food processing industries. Since improvement of their production was of great importance to reduce the final coast, cultural conditions were analyzed to optimize biosurfactants production from Bacillus subtilis SPB1 strain. A high yield of biosurfactants was obtained from a culture of B. subtilis using carbohydrate substrate as a carbon source; among carbohydrates, glucose enhanced the best surfactin production. The optimum glucose concentration was 40 g/L. Higher amount of biosurfactants was obtained using 5 g/L of urea as organic nitrogen source and applying C/N ratio of 7 with ammonium chloride as inorganic nitrogen source. The highest amount of biosurfactants was recorded with the addition of 2% kerosene. Moreover, it was shown, using an automated full-controlled 2.6 L fermenter, that aeration of the medium, which affected strongly the growth regulated biosurfactants synthesis by the producing cell. So that, low or high aerations lead to a decrease of biosurfactants synthesis yields. It was found that when using dissolved oxygen saturation of the medium at 30%, biosurfactants production reached 4.92 g/L

A demonstrator for bolometric interferometry

Bolometric Interferometry (BI) is one of the most promising techniques for precise measurements of the Cosmic Microwave Background polarization. In this paper, we present the results of DIBO (Demonstrateur d'Interferometrie Bolometrique), a single-baseline demonstrator operating at 90 GHz, built to proof the validity of the BI concept applied to a millimeter-wave interferometer. This instrument has been characterized in the laboratory with a detector at room temperature and with a 4 K bolometer. This allowed us to measure interference patterns in a clean way, both (1) rotating the source and (2) varying with time the phase shift among the two interferometer's arms. Detailed modelisation has also been performed and validated with measurements.Comment: 15 pages, 14 figure

Greffage de peptides pour limiter les infections sur des prothèses intraosseuses transcutanées pour amputations (ITAP)

Les prothèses intraosseuses transcutanées pour amputations (ITAP) représentent une alternative prometteuse par rapport aux prothèses orthopédiques actuellement utilisées en clinique puisqu’elles pourraient diminuer, entre autres, la douleur et l’inconfort chez les patients. Cependant, l’infection, surtout à l’interface implant /peau, reste une complication importante dans ce type de chirurgie orthopédique. Le but de ce projet de recherche est donc de limiter les infections sur une prothèse en alliage de titane (Ti6Al4V ELI).Deux approches ont été établies. La première consiste à promouvoir l’adhésion des cellules de la peau par les peptides d’adhésion KRGDS et KYIGSR, ce qui permettrait de sceller la partie de l’implant qui sort de l’os et ainsi limiter les infections et la deuxième à agir directement sur les bactéries en les éliminant, par le peptide antimicrobien, Magainine 2 (Mag 2).Pour ce travail de thèse, les deux peptides d’adhésion, soit KRGDS et KYIGSR et le peptide antimicrobien, Mag 2, ont été greffés de façon covalente et stable via les bras d’ancrage phosphonates et dopamine à la surface du matériau Ti6Al4V ELI. La caractérisation physico-chimique de ces surfaces a permis de valider le greffage covalent et stable de ces peptides. Des tests cellulaires et bactériens ont été effectués sur les surfaces Ti6Al4V ELI brutes et fonctionnalisées par les différents peptides. Pour les tests cellulaires, il y aune bonne adhésion et prolifération cellulaire des fibroblastes dermiques pour les 4types de matériaux Ti6Al4V ELI. Par contre, la viabilité cellulaire est améliorée pour les échantillons avec peptides greffés, surtout KRGDS et Mag 2. D’autant plus, l’attachement dermique est nettement meilleur sur les surfaces fonctionnalisées par Mag 2 également. Concernant les tests de microbiologie, les résultats obtenus avec les bactéries Staphylococcus epidermidis ATCC-12228 montrent un léger effet antibactérien de la Mag 2 greffée sur la surface Ti6Al4V ELI. Dans le cadre de ce projet, la fonctionnalisation de surface par le peptide antimicrobien Mag 2 est la meilleure alternative pour limiter les infections sur les matériaux Ti6Al4V ELI.Intraosseous Transcutaneous Amputation Prostheses (ITAPs) represent apromising alternative to orthopedic prostheses currently used in the clinic since they could reduce, among other things, pain and discomfort in patients. However, infection, especially at the implant / skin interface, remains a significant complicationin this type of orthopedic surgery. The aim of this research project is therefore to limit infections on a titanium alloy prosthesis (Ti6Al4V ELI). Two approaches have been established. The first is to promote the adhesion of skin cells by using the KRGDS and KYIGSR peptides, which would seal the part of the implant that comes out of the bone and thus limit infections and the second to act directly on bacteria by eliminating them, by using the antimicrobial peptide, Mag 2. For this thesis work, the two adhesion peptides, either KRGDS or KYIGSR and the antimicrobial peptide, Mag 2, were covalently grafted via the phosphonate and dopamine anchor arms to the surface of the Ti6Al4V ELI material. The physico-chemical characterization of these surfaces made it possible to validate the covalent and stable grafting of these peptides. Cellular and bacterial tests were carried out on bare Ti6Al4V ELI surfaces and functionalized by the various peptides. For cellular assays, there is good celladhesion and proliferation of dermal fibroblasts on the 4 types of Ti6Al4V ELI samples. In contrast, cell viability is improved for samples with grafted peptides,especially KRGDS and Mag 2. Moreover, dermal attachment is significantly betteron surfaces functionalized by Mag 2 as well. Regarding microbiology tests, the results obtained with Staphylococcus epidermidis ATCC12228 bacteria show a slight antibacterial effect of Mag 2 grafted onto the Ti6Al4V ELI surface. Within the framework of this project, the surface functionalization by the antimicrobial peptide Mag 2 is the best alternative to limit infections on Ti6Al4V ELI material

Agent-based simulations for coverage extensions in 5G networks and beyond

Device-to-device (D2D) communications is one of the key emerging technologies for the fifth generation (5G) networks and beyond. It enables direct communication between mobile users and thereby extends coverage for devices lacking direct access to the cellular infrastructure and hence enhances network capacity. D2D networks are complex, highly dynamic and will be strongly augmented by intelligence for decision making at both the edge and core of the network, which makes them particularly difficult to predict and analyze. Conventionally, D2D systems are evaluated, investigated and analyzed using analytical and probabilistic models (e.g., from stochastic geometry). However, applying classical simulation and analytical tools to such a complex system is often hard to track and inaccurate. In this paper, we present a modeling and simulation framework from the perspective of complex-systems science and exhibit an agent-based model for the simulation of D2D coverage extensions. We also present a theoretical study to benchmark our proposed approach for a basic scenario that is less complicated to model mathematically. Our simulation results show that we are indeed able to predict coverage extensions for multi-hop scenarios and quantify the effects of street-system characteristics and pedestrian mobility on the connection time of devices to the base station (BS). To our knowledge, this is the first study that applies agent-based simulations for coverage extensions in D2D