Antioxidant Capacity and Antimicrobial Activity of Commercial Samples of Guava Leaves (\u3cem\u3ePsidium guajava\u3c/em\u3e)

Psidium guajava is a small tree native to South and Central America. Guava leaves have traditionally been used for treating different illnesses. These benefits can be attributed to phenolics and flavonoids produced by guava. The chemical composition of guava leaf extracts was correlated with biological activity. Total phenolics, total flavonoids, ABTS/DPPH, TZM-bl, plaque reduction, XTT, spectrophotometric and Kirby-Bauer assays were used to test phenols, flavonoids, antioxidant properties, antiviral activity, cytotoxicity, and antibacterial activity, respectively. The median cytotoxicity concentration and half-maximal effective concentration values were obtained in order to determine antiviral selectivity against human immunodeficiency virus type 1 and herpes simplex virus type 1. Antibacterial activity against Escherichia coli and Bacillus subtilis were evaluated using a spectrophotometric assay and Kirby-Bauer test. The guava leaf extracts had a high phenol (0.8 to 2.1 GAE mg/mL) and flavonoid (62.7 to 182.1 Rutin Eq mg/g DW) content that correlated with high antioxidant capacity and selective antiviral activity (therapeutic index values above 10). Results of antibacterial tests indicated that the extracts have activity against gram-negative and gram-positive bacteria

Influence of the forming process on the mechanical behavior of a commingled carbon PPS composite part

In this research work, the influence of the forming process on commingled thermoplastic composite parts mechanical behavior was investigated. The aim of this work is to evaluate the influence of fabric shearing on the mechanical response of composite laminate. Different sheets with a given shear angle are manufactured. Tensile experimental results are compared with the properties obtained from a simple model based on the laminate plate theory for various off angles. Later, the link with a tetrahedron shape 3D part manufactured by punch deep drawing will be made

Antioxidant, antibacterial, and anti-SARS-CoV Activity of Commercial Products of \u3cem\u3eXylopia\u3c/em\u3e (\u3cem\u3eXylopia aethiopica\u3c/em\u3e)

Xylopia aethiopica (Annonaceae) is a spice and medicinal plant that grows wild in many West African countries (from Liberia to Nigeria) and is locally known as Guinea pepper, grains of Selim, hwentia and uda. The dried fruits are used as a flavoring for soups and traditionally in decoctions as an analgesic and anti-inflammatory, as well as a treatment for infections. The medicinal properties of the fruits are associated with the presence of phenolics and essential oil constituents. We studied the total phenols, total flavonoids, and antioxidant activity in different X. aethiopica extracts using spectrophotometry. We found variation in total phenolic and flavonoids and antioxidant capacity between different samples and different extraction solvents. Antibacterial activity against Escherichia coli and Bacillus subtilis were evaluated using a spectrophotometric assay and Kirby-Bauer test. Additionally, a pseudoviral cell-based assay was used to test the antiviral activity against severe acute respiratory syndrome coronaviruses (SARS-CoV-1 and SARS-CoV-2). High total phenolic and flavonoid content was correlated with high antioxidant capacity. Results of antibacterial tests indicated that one Xylopia extract potentially has strong antibacterial activity against gram-positive bacteria B. subtilis. The pseudoviral assay showed moderate antiviral activity against SARS-CoV-1 and SARS-CoV-2

Results of a phase 1, randomized, placebocontrolled first-in-human trial of griffithsin formulated in a carrageenan vaginal gel

HIV pre-exposure prophylaxis (PrEP) is dominated by clinical therapeutic antiretroviral (ARV) drugs. Griffithsin (GRFT) is a non-ARV lectin with potent anti-HIV activity. GRFT’s preclinical safety, lack of systemic absorption after vaginal administration in animal studies, and lack of cross-resistance with existing ARV drugs prompted its development for topical HIV PrEP. We investigated safety, pharmacokinetics (PK), pharmacodynamics (PD), and immunogenicity of PC-6500 (0.1% GRFT in a carrageenan (CG) gel) in healthy women after vaginal administration. This randomized, placebo-controlled, parallel group, double-blind first-in-human phase 1 study enrolled healthy, HIV-negative, non-pregnant women aged 24–45 years. In the open label period, all participants (n = 7) received single dose of PC- 6500. In the randomized period, participants (n = 13) were instructed to self-administer 14 doses of PC-6500 or its matching CG placebo (PC-535) once daily for 14 days. The primary outcomes were safety and PK after single dose, and then after 14 days of dosing. Exploratory outcomes were GRFT concentrations in cervicovaginal fluids, PD, inflammatory mediators and gene expression in ectocervical biopsies. This trial is registered with ClinicalTrials. gov, number NCT02875119. No significant adverse events were recorded in clinical or laboratory results or histopathological evaluations in cervicovaginal mucosa, and no anti-drug (GRFT) antibodies were detected in serum. No cervicovaginal proinflammatory responses and no changes in the ectocervical transcriptome were evident. Decreased levels of proinflammatory chemokines (CXCL8, CCL5 and CCL20) were observed. GRFT was not detected in plasma. GRFT and GRFT/CG in cervicovaginal lavage samples inhibited HIV and HPV, respectively, in vitro in a dose-dependent fashion. These data suggest GRFT formulated in a CG gel is a safe and promising on-demand multipurpose prevention technology product that warrants further investigation

Etude de la variabilite intrasaisonniere de l'atmosphere tropicale simulee par un modele de circulation generale

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Using X-Ray tomography to evaluate porosities in composite parts

National audienceIn aeronautics and automotive applications, manufacturing composite by consolidation is mainly used in order to answer current weigh reduction and optimization cost problematics. During the process, voids appear in the composite parts. An adequate process cycle must be selected to reach minimum porosity content within the laminate. These voids have influence on mechanical properties of composite parts. That's why, it is important to study voids in composite parts. Objective of this study is to develop a new way to study porosity in composite parts. This method permits not only to measure the voids content but also the voids size, location and morphology.The non-destructive technic consists on using X-ray beam to analyse the sample structure. The intensity of the attenuated X-ray is recorded from different angular position of the sample so as to get the spatial distribution of the absorption coefficient within the laminate by using a reconstruction algorithm. The sample is represented as voxels, which correspond individualy to the intensity of the material density (grayscale value). Objects, which have a low material density as voids, absorbs less X-ray than a higher material density as fibre and matrix. Consequently, in this case, porosities objet have the lowest attenuation coefficient with a grey value close to 0 (black color). On the contrary, fibre and matrix objects have a higher gray value (approching white color for the matrix one). All specimen were analysed with a Easytom 130 tomograph. Scan resolution, in terms of voxel size, reached for this study is 11.2 μm³ +/- 0.8 μm³. Reconstruted 3D images were analysed with post-processing software ImageJ and the plug-in 3D Objects Counter.To analyse voids within the laminates, it is necessary to separate it from matrix and carbon fibres into two groups, with segmentation method. The grey threshold, chosen for void segmentation, is taken at the first inflexion point of the hystogramm of the fibres/matrix image for all X-ray slices. The grey threshold must be determined for each X-ray slice to minimize errors. With this segmentation, voids location, size and morphology are analysed. Voids size permits to define micro and macro voids.This method was applied on carbon composite with different consolidation cycle in terms of consolidation pressure, processing temperature, consolidation time and vacuum levels

Coupling thermal and kinematic full field measurement for the mechanical characterization of metals at high temperature

International audienceMechanical tests were developed to characterize metallic materials at high temperature. Specimens used in these tests can have 3D complex geometry. During the tests, measuring both thermal and kinematic fields is important. Thermal measurement is well control for plane shape samples with a relatively homogenous surface state, but not when the part is convex or concave. Kinematic measurement is well controlled at room temperature but not at high temperature. The aim of this study is to develop a device to measure both temperature and shape during mechanical testing with a 3D complex geometry sample at high temperature

Utilisation de la corrélation d'images pour le suivi de la mise en forme de renfort textile dans le cadre de la fabrication de pièces composites pour l'aéronautique

Colloque avec actes et comité de lecture. Internationale.National audienceFor several years, structural or semi-structural aeronautics parts manufactured with composite materials have been developped. The geometrical complexity of these parts requires the use of textile preforms with the integration of polymeric yarns in order to optimize the deformability of the fabric during the forming process. Due to the non-linear in plane shear mechanical behavior, local stiffning of the preform appears during this forming. These discontinuities affect the mechanical properties and material health of the final composite part.The objective of this work is to determine the final mechanical properties of a composite part from the forming of the textile reinforcement, using a tracking of the strain field by 3D digital image correlation.The study is divided into three parts: (1) the mechanical characterization of the in plane shear behaviour of the textile reinforcement through Bias tests, (2) drapability tests to establish strain field and shear angles during draping and (3) mechanical tests on the final composite in order to make the link between the shear angles of the textile reinforcement and the mechanical properties of the final composite.According to the firsts part of the study, the shear locking angle of the studied textile reinforcement, a carbon/PPS, is 38.5° ±2.3°. The draping tests show that the shear-locking angle is reached in certain areas for a half-sphere and a parallelepiped shape. The last part of the study is being finalized.Depuis plusieurs années, les matériaux composites sont utilisés dans le domaine de l'aéronautique pour la mise en oeuvre de pièces structurelles ou semi-structurelles. La complexité géométrique de ces pièces non développables nécessite l'utilisation de préformes textiles afin d'optimiser la déformabilité du tissu pourla mise en forme. Durant cette mise en forme, du fait du comportement non-linéaire en cisaillement des tissus,des rigidifications locales des préformes apparaissent. Ces modifications impactent les propriétés mécaniques et la santé matière de la pièce composite finale. L'objectif de ces travaux est de déterminer les propriétés mécaniques finales d'une pièce composite à partir de la mise en forme du renfort textile, en utilisant un suivi du champ de déformation par des bancs de stéréocorrélation d'images. L'étude se divise en trois parties : (1) la caractérisation du renfort textile en cisaillement plan à l'aide de l'essai Bias Test, (2) des essais de drapabilité afin d'établir les champs de déformation et les angles de cisaillement au cours du drapage et (3) des essais mécaniques sur les composites finaux afin de faire le lien entre les angles de cisaillement du renfort textile et les propriétés mécaniques du composite. D'après la première partie de l'étude, l'angle de blocage en cisaillement du renfort textile d'étude, un carbone/PPS, est de 38,5° ±2,3°. Les essais de drapage montrent que l'angle de blocage en cisaillement est atteint dans certaines zones pour une demi-sphère et une forme parallélépipédique. La dernière partie est en cours de finalisation

Diastereocontrolled addition of organometallic reagents to S-chiral N-(tert-butanesulfinyl)-α-fluoroenimines

International audienc

MIV-150/zinc acetate gel inhibits cell-associated simian-human immunodeficiency virus reverse transcriptase infection in a macaque vaginal explant model

The transmission of both cell-free and cell-associated immunodeficiency viruses has been demonstrated directly in multiple animal species and possibly occurs in humans, as suggested by genotyping of the infecting human immunodeficiency virus (HIV) in acutely infected women and in semen from their partners. Therefore, a microbicide may need to block both mechanisms of HIV transmission to achieve maximum efficacy. To date, most of the preclinical evaluation of candidate microbicides has been performed using cell-free HIV. New models of mucosal transmission of cell-associated HIV are needed to evaluate candidate microbicide performance. The MIV-150/zinc acetate/carrageenan (MZC) gel protects Depo-Provera-treated macaques against cell-free simian-human immunodeficiency virus reverse transcriptase (SHIV-RT) infection when applied vaginally up to 8 h before challenge. We recently demonstrated the potent activity of MZC gel against cell-free SHIV-RT in macaque vaginal explants. In the current study, we established a cell-associated SHIV-RT infection model of macaque vaginal tissues and tested the activity of MZC gel in this model. MZC gel protected tissues against cell-associated SHIV-RT infection when present at the time of viral exposure or when applied up to 4 days prior to viral challenge. These data support clinical testing of the MZC gel. Overall, our ex vivo model of cell-associated SHIV-RT infection in macaque vaginal mucosa complements the cell-free infection models, providing tools for prioritization of products that block both modes of HIV transmission