Analyse du comportement dynamique de mousses de polyuréthane par des tests vibratoires

L’objectif de cet article est de décrire les techniques expérimentales et l’identification des propriétés dynamiques de mousses de polyuréthane. En effet, le niveau de confort d’un siège automobile est établien considérant les propriétés quasi-statiques – densité, portance et résilience – et dynamiques – transmissibilité – de la mousse flexible de polyuréthane. Notre dispositif d’essai est un système à un degré de liberté, composé d’un dispositif expérimental reposant sur le vérin d’une machine d’essai dynamique. Ce dispositif expérimental est composé d’un plateau supérieur avec une masse libre et d’un plateau inférieur solidaire de la machine d’essai, entre lesquels est placé un échantillon de mousse de dimensions100x100x50 mm3. Les vibrations transmises à travers la mousse sont mesurées pour déterminerles caractéristiques dynamiques de l’échantillon et permettent de réaliser le diagramme de Bodede la transmissibilité de l’échantillon. Cinq types de mousses de polyuréthane utilisées dans l’automobile seront comparés dans cet article

Evaluating Prophylactic Effect of Bovine Colostrum on Intestinal Barrier Function in Zonulin Transgenic Mice : A Transcriptomic Study

The intestinal barrier comprises a single layer of epithelial cells tightly joined to form a physical barrier. Disruption or compromise of the intestinal barrier can lead to the inadvertent activation of immune cells, potentially causing an increased risk of chronic inflammation in various tissues. Recent research has suggested that specific dietary components may influence the function of the intestinal barrier, potentially offering a means to prevent or mitigate inflammatory disorders. However, the precise mechanism underlying these effects remains unclear. Bovine colostrum (BC), the first milk from cows after calving, is a natural source of nutrients with immunomodulatory, anti-inflammatory, and gut-barrier fortifying properties. This novel study sought to investigate the transcriptome in BC-treated Zonulin transgenic mice (Ztm), characterized by dysbiotic microbiota, intestinal hyperpermeability, and mild hyperactivity, applying RNA sequencing. Seventy-five tissue samples from the duodenum, colon, and brain of Ztm and wild-type (WT) mice were dissected, processed, and RNA sequenced. The expression profiles were analyzed and integrated to identify differentially expressed genes (DEGs) and differentially expressed transcripts (DETs). These were then further examined using bioinformatics tools. RNA-seq analysis identified 1298 DEGs and 20,952 DETs in the paired (Ztm treatment vs. Ztm control) and reference (WT controls) groups. Of these, 733 DEGs and 10,476 DETs were upregulated, while 565 DEGs and 6097 DETs were downregulated. BC-treated Ztm female mice showed significant upregulation of cingulin (Cgn) and claudin 12 (Cldn12) duodenum and protein interactions, as well as molecular pathways and interactions pertaining to tight junctions, while BC-treated Ztm males displayed an upregulation of transcripts like occludin (Ocln) and Rho/Rac guanine nucleotide exchange factor 2 (Arhgf2) and cellular structures and interfaces, protein-protein interactions, and organization and response mechanisms. This comprehensive analysis reveals the influence of BC treatment on tight junctions (TJs) and Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) signaling pathway gene expressions. The present study is the first to analyze intestinal and brain samples from BC-treated Ztm mice applying high-throughput RNA sequencing. This study revealed molecular interaction in intestinal barrier function and identified hub genes and their functional pathways and biological processes in response to BC treatment in Ztm mice. Further research is needed to validate these findings and explore their implications for dietary interventions aimed at improving intestinal barrier integrity and function. The MGH Institutional Animal Care and Use Committee authorized the animal study (2013N000013).Peer reviewe

Prophylactic Effect of Bovine Colostrum on Intestinal Microbiota and Behavior in Wild-Type and Zonulin Transgenic Mice

Funding Information: This research was partly supported by the Spector Family Foundation to M.F.; the MGH ECOR Feasibility Grant to A.M.R.; European Commission, award number 825033 “GEMMA project” funded on Horizon 2020 program (call H2020-SC1-BHC -03-2018) to A.F.; the Fulbright Foundation, the Leifur Eiríksson Foundation, University of Iceland Research Fund, and the Nutricia Research Foundation to B.A.; the Uehara Memorial Foundation Overseas Postdoctoral Fellowships and the Ito Foundation for the Promotion of Medical Science Travel Grants for Overseas Exchange to T.K. Publisher Copyright: © 2022 by the authors.The microbiota–gut–brain axis (MGBA) involves bidirectional communication between intestinal microbiota and the gastrointestinal (GI) tract, central nervous system (CNS), neuroendocrine/neuroimmune systems, hypothalamic–pituitary–adrenal (HPA) axis, and enteric nervous system (ENS). The intestinal microbiota can influence host physiology and pathology. Dysbiosis involves the loss of beneficial microbial input or signal, diversity, and expansion of pathobionts, which can lead to loss of barrier function and increased intestinal permeability (IP). Colostrum, the first milk from mammals after birth, is a natural source of nutrients and is rich in oligosaccharides, immunoglobulins, growth factors, and anti-microbial components. The aim of this study was to investigate if bovine colostrum (BC) administration might modulate intestinal microbiota and, in turn, behavior in two mouse models, wild-type (WT) and Zonulin transgenic (Ztm)—the latter of which is characterized by dysbiotic microbiota, increased intestinal permeability, and mild hyperactivity—and to compare with control mice. Bioinformatics analysis of the microbiome showed that consumption of BC was associated with increased taxonomy abundance (p = 0.001) and diversity (p = 0.004) of potentially beneficial species in WT mice and shifted dysbiotic microbial community towards eubiosis in Ztm mice (p = 0.001). BC induced an anxiolytic effect in WT female mice compared with WT female control mice (p = 0.0003), and it reduced anxiogenic behavior in Ztm female mice compared with WT female control mice (p = 0.001), as well as in Ztm male mice compared with WT BC male mice (p = 0.03). As evidenced in MGBA interactions, BC supplementation may well be applied for prophylactic approaches in the future. Further research is needed to explore human interdependencies between intestinal microbiota, including eubiosis and pathobionts, and neuroinflammation, and the potential value of BC for human use. The MGH Institutional Animal Care and Use Committee authorized the animal study (2013N000013).Peer reviewe

A theoretical approach to spot active regions in antimicrobial proteins

Background: Much effort goes into identifying new antimicrobial compounds able to evade the increasing resistance of microorganisms to antibiotics. One strategy relies on antimicrobial peptides, either derived from fragments released by proteolytic cleavage of proteins or designed from known antimicrobial protein regions. Results: To identify these antimicrobial determinants, we developed a theoretical approach that predicts antimicrobial proteins from their amino acid sequence in addition to determining their antimicrobial regions. A bactericidal propensity index has been calculated for each amino acid, using the experimental data reported from a high-throughput screening assay as reference. Scanning profiles were performed for protein sequences and potentially active stretches were identified by the best selected threshold parameters. The method was corroborated against positive and negative datasets. This successful approach means that we can spot active sequences previously reported in the literature from experimental data for most of the antimicrobial proteins examined. Conclusion: The method presented can correctly identify antimicrobial proteins with an accuracy of 85% and a sensitivity of 90%. The method can also predict their key active regions, making this a tool for the design of new antimicrobial drugs

IDENTIFICATION DE NOUVEAUX GENES INDUITS LORS DE LA REPONSE IMMUNITAIRE DE LA DROSOPHILE

POUR CARACTERISER DE NOUVEAUX GENES DE LA REPONSE IMMUNITAIRE DE LA DROSOPHILE, J'AI UTILISE UNE TECHNIQUE DE PCR DIFFERENTIELLE PERMETTANT D'ISOLER DES ARNM DONT LA SYNTHESE EST MODULEE APRES UN STIMULUS IMMUN. CE CRIBLE M'A PERMIS D'IDENTIFIER, OUTRE DES GENES CODANT DES PEPTIDES ANTIMICROBIENS DEJA REPERTORIES, DEUX GROUPES DE GENES CODANTS DE NOUVELLES PROTEASES A SERINES ET DES INHIBITEURS DE PROTEASE DE LA FAMILLE KUNITZ. J'AI MIS EN EVIDENCE, QUE L'EXPRESSION DE CES DIFFERENTS GENES EST AUGMENTEE EN CONTEXTE INFECTIEUX, QUE LEURS CINETIQUES D'INDUCTION SONT VARIABLES SUIVANT LE GENE CONSIDERE ET L'AGENT INDUCTEUR UTILISE ET QUE LEUR EXPRESSION EST ALTEREE CHEZ DES DROSOPHILES MUTANTES POUR LES VOIES DE SIGNALISATION DE L'IMMUNITE. L'ANALYSE A L'AIDE D'ANTICORPS DIRIGES CONTRE UNE DES PROTEASES A PERMIS DE MONTRER QUE LA PROTEINE EST PRODUITE PAR LES CELLULES DU CORPS GRAS (UN EQUIVALENT FONCTIONNEL DU FOIE DE MAMMIFERES QUI CONSTITUE LE PRINCIPAL TISSU IMMUNOCOMPETENT CHEZ LA DROSOPHILE) ET QU'ELLE APPARAIT DANS L'HEMOLYMPHE RAPIDEMENT APRES UN BLESSURE SEPTIQUE. PLUSIEURS ACTIVITES PROTEOLYTIQUES DE L'HEMOLYMPHE LIEES A DIFFERENTS MECANISMES DE DEFENSE (COAGULATION, MELANISATION, PRODUCTION DE MOLECULES SIGNALISANTES) SONT DECLENCHES RAPIDEMENT APRES UN STIMULUS IMMUNITAIRE CHEZ LA DROSOPHILE. LES GENES QUE J'AI IDENTIFIES SONT DE BONS CANDIDATS POUR PARTICIPER A CES CASCADES PROTEOLYTIQUES. AFIN DE CARACTERISER LEURS FONCTIONS, J'AI UTILISE DEUX APPROCHES GENETIQUES DIFFERENTES : UNE MUTAGENESE PAR REMOBILISATION D'UN ELEMENT TRANSPOSABLE ET LA GENERATION DE DROSOPHILES TRANSGENIQUES. UN ELEMENT P A ETE INSERE DANS LE GROUPE DE GENES CODANT LES INHIBITEURS DE PROTEASE AFIN DE PERTURBER LEUR EXPRESSION. J'AI ANALYSE DES LIGNEES TRANSGENIQUES SUREXPRIMANT UNE DES PROTEASES SOUS FORMES CONSTITUTIVEMENT ACTIVE, INACTIVE (ZYMOGENE) OU MUTEE AU NIVEAU DU SITE CATALYTIQUE. L'ANALYSE DE CES OUTILS GENETIQUES SE POURSUIT ACTUELLEMENT.STRASBOURG-Sc. et Techniques (674822102) / SudocSudocFranceF

Harmonic Vibration Test for the Analysis of the Dynamic Behaviour of Polyurethane Foams

International audienceThe main goal of this paper is to describe experimental techniques and identification of dynamic properties offlexible polyurethane foam. Indeed, automotive seat comfort level is established with considering quasi-static -density core, hysteresis loss and compression set - and dynamic -transmissibility and damping - properties offlexible polyurethane foams. Our dynamic system, modeled as a single degree-of-freedom system, is composedof an experimental device with a free mass on the top and a shaker on the basement. The first one, a rigid block,is mounted on a 100x100x50 mm cube sample of foam material and the second one excites the device with harmonicvibration. The steady-state response of a polyurethane foam sample – after the same number of cycles –to harmonic vibration is analyzed for different excitation amplitude level and for different initial compression level,corresponding respectively to various road surface conditions and to various apparent-mass. The transmittedvibration between the shaker and the free mass is measured to determine the damping power and the filter bandof polyurethane foam, and enables to trace the Bode magnitude and phase plots of the dynamic stiffness functionof the system. The results presented here compare 3 types of OEM foams

Δcps1 vaccine protects dogs against experimentally induced coccidioidomycosis

Coccidioidomycosis is a significant health problem of dogs and humans in endemic regions, especially California and Arizona in the U.S. Both species would greatly benefit from a vaccine to prevent this disease. A live avirulent vaccine candidate, Δcps1, was tested for tolerability and efficacy to prevent pulmonary coccidioidomycosis in a canine challenge model. Vaccine injection-site reactions were transient and there were no systemic effects observed. Six of seven vaccine sites tested and all draining lymph nodes were sterile post-vaccination. Following infection with Coccidioides posadasii, strain Silveira, arthroconidia into the lungs, dogs given primary and booster vaccinations had significantly reduced lung fungal burdens (P = 0.0003) and composite disease scores (P = 0.0002) compared to unvaccinated dogs. Dogs vaccinated once had fungal burdens intermediate between those given two doses or none, but disease scores were not significantly different from unvaccinated (P = 0.675). Δcps1 was well-tolerated in the dogs and it afforded a high level of protection when given as prime and boost. These results drive the Δcps1 vaccine toward a licensed veterinary vaccine and support continued development of this vaccine to prevent coccidioidomycosis in humans.Open access articleThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]