53 research outputs found
Detection of Torquetenovirus and Redondovirus DNA in Saliva Samples from SARS-CoV-2-Positive and -Negative Subjects
Torquetenovirus (TTV) and Redondovirus (ReDoV) are the most prevalent viruses found in the human respiratory virome in viral metagenomics studies. A large-scale epidemiological study was performed to investigate their prevalence and loads in saliva samples according to SARS-CoV-2 status
Density, extractives and decay resistance variabilities within branch wood from four agroforestry hardwood species
Agroforestry practices like pruning trees to control the light flux to crops produce every year a large volume of branches which is valorized by farmers as mulching or energy fuel. However, according to the literature, the wood of branches shows higher rates of polyphenols than stem wood and this can open some new perspectives for branch exploitation. In this study, the wood properties (density, mechanical properties, extractive content and decay resistance) were determined on branches of different sizes from oak, chestnut, poplar and walnut trees collected in two agroforestry systems. These properties were evaluated according to the wood age and the sampling position along the radial and longitudinal axes of the branch. All samples were analyzed by NIR-Spectroscopy and a predicting model aimed to assess the branch wood properties has been developed. Wood characteristics largely vary between species and do not exactly follow the same trends from one species to another. Overall, hardwood density of branches is similar to that of trunks, the content in wood extractives follows similar evolutions, and the decay resistance of branch wood does not seem to be really impacted by its position along the branch. Reliable NIRS models were built to easily predict the wood density and extractives content of agroforestry branches. The extractives content and the decay resistance of branch hardwood appear to be substantially lower than those of trunks, which suggests a non-suitability of branch wood for developing highvalued green chemistry
Lrp5 Is Not Required for the Proliferative Response of Osteoblasts to Strain but Regulates Proliferation and Apoptosis in a Cell Autonomous Manner
Although Lrp5 is known to be an important contributor to the mechanisms regulating bone mass, its precise role remains unclear. The aim of this study was to establish whether mutations in Lrp5 are associated with differences in the growth and/or apoptosis of osteoblast-like cells and their proliferative response to mechanical strain in vitro. Primary osteoblast-like cells were derived from cortical bone of adult mice lacking functional Lrp5 (Lrp5−/−), those heterozygous for the human G171V High Bone Mass (HBM) mutation (LRP5G171V) and their WT littermates (WTLrp5, WTHBM). Osteoblast proliferation over time was significantly higher in cultures of cells from LRP5G171V mice compared to their WTHBM littermates, and lower in Lrp5−/− cells. Cells from female LRP5G171V mice grew more rapidly than those from males, whereas cells from female Lrp5−/− mice grew more slowly than those from males. Apoptosis induced by serum withdrawal was significantly higher in cultures from Lrp5−/− mice than in those from WTHBM or LRP5G171V mice. Exposure to a single short period of dynamic mechanical strain was associated with a significant increase in cell number but this response was unaffected by genotype which also did not change the ‘threshold’ at which cells responded to strain. In conclusion, the data presented here suggest that Lrp5 loss and gain of function mutations result in cell-autonomous alterations in osteoblast proliferation and apoptosis but do not alter the proliferative response of osteoblasts to mechanical strain in vitro
Time since Onset of Disease and Individual Clinical Markers Associate with Transcriptional Changes in Uncomplicated Dengue
Dengue virus (DENV) infection causes viral haemorrhagic fever that is characterized by extensive activation of the immune system. The aim of this study is to investigate the kinetics of the transcriptome signature changes during the course of disease and the association of genes in these signatures with clinical parameters. Sequential whole blood samples from DENV infected patients in Jakarta were profiled using affymetrix microarrays, which were analysed using principal component analysis, limma, gene set analysis, and weighted gene co-expression network analysis. We show that time since onset of disease, but not diagnosis, has a large impact on the blood transcriptome of patients with non-severe dengue. Clinical diagnosis (according to the WHO classification) does not associate with differential gene expression. Network analysis however, indicated that the clinical markers platelet count, fibrinogen, albumin, IV fluid distributed per day and liver enzymes SGOT and SGPT strongly correlate with gene modules that are enriched for genes involved in the immune response. Overall, we see a shift in the transcriptome from immunity and inflammation to repair and recovery during the course of a DENV infection. Time since onset of disease associates with the shift in transcriptome signatures from immunity and inflammation to cell cycle and repair mechanisms in patients with non-severe dengue. The strong association of time with blood transcriptome changes hampers both the discovery as well as the potential application of biomarkers in dengue. However, we identified gene expression modules that associate with key clinica
Non-Overlapping Functions for Pyk2 and FAK in Osteoblasts during Fluid Shear Stress-Induced Mechanotransduction
Mechanotransduction, the process by which cells convert external mechanical stimuli such as fluid shear stress (FSS) into biochemical changes, plays a critical role in maintenance of the skeleton. We have proposed that mechanical stimulation by FSS across the surfaces of bone cells results in formation of unique signaling complexes called mechanosomes that are launched from sites of adhesion with the extracellular matrix and with other bone cells [1]. Deformation of adhesion complexes at the cell membrane ultimately results in alteration of target gene expression. Recently, we reported that focal adhesion kinase (FAK) functions as a part of a mechanosome complex that is required for FSS-induced mechanotransduction in bone cells. This study extends this work to examine the role of a second member of the FAK family of non-receptor protein tyrosine kinases, proline-rich tyrosine kinase 2 (Pyk2), and determine its role during osteoblast mechanotransduction. We use osteoblasts harvested from mice as our model system in this study and compared the contributions of Pyk2 and FAK during FSS induced mechanotransduction in osteoblasts. We exposed Pyk2+/+ and Pyk2−/− primary calvarial osteoblasts to short period of oscillatory fluid flow and analyzed downstream activation of ERK1/2, and expression of c-fos, cyclooxygenase-2 and osteopontin. Unlike FAK, Pyk2 was not required for fluid flow-induced mechanotransduction as there was no significant difference in the response of Pyk2+/+ and Pyk2−/− osteoblasts to short periods of fluid flow (FF). In contrast, and as predicted, FAK−/− osteoblasts were unable to respond to FF. These data indicate that FAK and Pyk2 have distinct, non-redundant functions in launching mechanical signals during osteoblast mechanotransduction. Additionally, we compared two methods of generating FF in both cell types, oscillatory pump method and another orbital platform method. We determined that both methods of generating FF induced similar responses in both primary calvarial osteoblasts and immortalized calvarial osteoblasts
Raman Intensities of the ν1/ν3 Dyad of 28SiH4
0022-2852The stimulated Raman spectrum of 28SiH4 has been recorded in the ν1/ν3 region between 2182 and 2190 cm(-1). The intensities of the Raman transitions were modeled using a dyad scheme for the two interacting bands with a first-order polarizability expansion. The involved polarizability parameter; have been adjusted to fit about 800 measured intensities of transitions reaching upper states up to J = 18. The resulting standard deviation is about 10%. (C) 1994 Academic Press, Inc
Influence of bismuth on magnetism and magnetocaloric properties of LaFe11.6Si1.4 intermetallic compound
International audienc
Dépistage du kératocône dans une population universitaire au Maroc Keratoconus screening in a Moroccan students’ population
Objectif : Dépister le kératocône dans une population universitaire à Oujda en utilisant la topographie cornéenne afin d’en déterminer la prévalence et les éventuels facteurs de risque.Matériels et méthodes :Trois promotions des étudiants en médecine au centre hospitalier universitaire Mohammed VI d’Oujda au Maroc, entre octobre et décembre 2017, ont été contactées.  Soixante-quinze étudiants ont accepté de participer au protocole de dépistage constitué d’un questionnaire et d’un examen topographique d’élévation type PENTACAM. L’analyse des cartes s’est faite par les logiciels d’intelligence fournis avec le topographe et par une lecture qualitative des cartes. L’ensemble des analyses statistiques a été réalisé avec la version du logiciel SPSS pour Windows version20. Les variables quantitatives ont été exprimées en moyennes et écart types, et les variables qualitatives ont été exprimées en effectifs et pourcentages.Résultats :Soixante-quinze volontaires des 180 contactés ont participé à l’étude (41.6%), dont 43 hommes (42.7%) et 32 femmes (57.3%). La moyenne d’Age était de 21.8 ans. Trente-sept étudiants (49.4%) étaient connus amétropes : 19 (25.4%) participants connus myopes, 14 (18.6%) astigmates et 4 (5.3%) hypermétropes. Deux étudiants sont connus porteurs de kératocône bilatéral. La prévalence du kératocône était de 5.3% dont 2.6% déjà connus. Sept étudiants (9.3%) ont rapporté une histoire familiale de kératocône dont seulement un était porteur de la pathologie. Le frottement des yeux a été retrouvé associé de façon statistiquement significative au kératocône dans notre échantillon.Conclusion Le kératocône est assez fréquent dans une population d’étudiants en médecine à Oujda. Cette étude représente un point de départ à des études ultérieures sur une population plus large et plus représentative de la population générale marocaine dans le but de mieux connaître la prévalence du kératocône dans notre pays.
Magnetic properties and magnetocaloric effect in amorphous Co35Er65 ribbon
International audienc
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