Search results for "PERMEABILITY"
showing 10 items of 596 documents
In Silico Prediction of Caco-2 Cell Permeability by a Classification QSAR Approach
2011
In the present study, 21 validated QSAR models that discriminate compounds with high Caco-2 permeability (Papp ≥8×10(-6) cm/s) from those with moderate-poor permeability (Papp <8×10(-6) cm/s) were developed on a novel large dataset of 674 compounds. 20 DRAGON descriptor families were used. The global accuracies of obtained models were ranking between 78-82 %. A general model combining all types of molecular descriptors was developed and it classified correctly 81.56 % and 83.94 % for training and test sets, respectively. An external set of 10 compounds was predicted and 80 % was correctly assessed by in vitro Caco-2 assays. The potential use of the final model was evaluated by a virtual s…
Advances in the Testing of the Hydro-mechanical Behaviour of Shales
2013
The paper presents some of the advanced experimental techniques and apparatuses that have been developed by the authors for testing the hydromechanical behaviour of shales. A methodology established for the analysis of the water retention behaviour in non-isochoric conditions is introduced; the method allows for the determination of the main drying and wetting paths in addition to the volume change response upon total suction variations. A high-pressure oedometric cell is then presented; the apparatus allows for the analysis of the transition from the pre-yield behaviour to the normally consolidated state. The analysis of the settlement versus time curves yields information on the permeabil…
Water vapour permeability, thermal and wetting properties of whey protein isolate based edible films
2010
Abstract This study deals with the effect of whey protein isolate (WPI) and glycerol (GLY) used as a plasticizer on some physical properties of cast whey protein isolate (WPI) films. Films were prepared from heated (80 °C for 30 min) aqueous solutions of WPI at 7, 8, 9 and 10% (w/w), GLY (40%, w/w, of WPI) and WPI at 8% (w/w), GLY (30, 40, and 60%, w/w, of WPI). For all types of films, water vapour permeability for four relative humidity differentials (30–100%, 30–84%, 30–75%, and 30–53%), surface and thermal properties were measured. Varying the proportion of WPI and GLY in edible films had some effect on water vapour permeability, wetting and thermal properties of WPI films. A cumulative …
Mangiferin nanoemulsions in treatment of inflammatory disorders and skin regeneration
2018
Abstract In this paper mangiferin nanoemulsions were developed using hyaluronic acid of different molecular weight, in absence or presence of Transcutol-P. An extensive study was carried out on the physico-chemical properties of nanoemulsions. Nanosizer and transmission electron microscopy showed oil droplets average size 296 nm with monodisperses distribution (PI ≤ 0.30). The zeta potential was highly negative (−30 mV). FTIR analysis confirms the existence of physical interactions among compounds. Rheological measurements allowed to conclude that all formulations present a pseudoplastic behavior (s ∼ 0.4) in presence of the biopolymer. Moreover, mangiferin release depends on the molecular …
Recombinant hydroperoxide lyase for the production of aroma compounds: Effect of substrate on the yeast Yarrowia lipolytica
2008
International audience; The aim of this study was to investigate the action mechanism of linoleic acid hydroperoxides (HPOD), which are the major substrates of hydroperoxide lyase for the production of flavour compounds, on the yeast Yarrowia lipolytica by evaluating their effect on the oxidative state of the cells. The total antioxidant capacity (TAC) and the activity of the main antioxidant enzymes, such as glutathione reductase, glutathione peroxidase and superoxide dismutase, of cells treated with HPOD were studied. The potential role of intracellular glutathione, including reduced glutathione (GSH) and oxidized glutathione (GSSG), in conferring HPOD resistance was also been examined. T…
Functional exploration of the stress response in microorganisms of technological interest : dynamics of membrane response after an ethanol shock in S…
2015
The study of membrane response induced by ethanol stress in Saccharomyces cerevisiae aims to understand mechanisms involved in the survival of eukaryotic cells submitted to high ethanol concentrations. The cell membrane by its position between the intra- and extracellular environment is the first target of ethanolic perturbations. Experiments performed in this study aimed to characterize the maintain of the functional integrity of the membrane in relation to the sterol composition in the yeast S. cerevisiae submitted to different types of ethanolic disturbances: increasing concentrations of ethanol in the growth medium; ethanolic shocks of increasing magnitude; shock 20% ethanol for 15 minu…
Contribution à la compréhension de l'influence des paramètres de formulation et de procédé sur la structure et les propriétés fonctionnelle de films …
2012
The aim of this study is the analysis of structure and transfer mechanisms through chitosan based food packaging materials with incorporated carvacrol as a model of antimicrobial active substance. Integration of composition parameters, structure, processing and drying of chitosan systems is correlated to its physico chemical and functional properties. Understanding and detailed analyses of processing parameters is crucial in production of active chitosan coatings applied on conventional materials such as polyethylene. So, the knowledge of composition and microstructure in association to environmental conditions, control the retention and the release kinetics of carvacrol from chitosan film.…
Glutathione in Cancer Cell Death
2011
Glutathione (L-γ-glutamyl-L-cysteinyl-glycine; GSH) in cancer cells is particularly relevant in the regulation of carcinogenic mechanisms; sensitivity against cytotoxic drugs, ionizing radiations, and some cytokines; DNA synthesis; and cell proliferation and death. The intracellular thiol redox state (controlled by GSH) is one of the endogenous effectors involved in regulating the mitochondrial permeability transition pore complex and, in consequence, thiol oxidation can be a causal factor in the mitochondrion-based mechanism that leads to cell death. Nevertheless GSH depletion is a common feature not only of apoptosis but also of other types of cell death. Indeed rates of GSH synthesis and…
Transport parameters for aroma compounds through i-carrageenan and sodium alginate-based edible films
2011
In an effort to produce more environmentally friendly materials, renewable and biodegradable biopolymers have been investigated as coating materials. Edible films obtained from i-carrageenan and sodium alginates have good mechanical characteristics, are emulsion stabilizers, and decrease oxygen transfer. The addition of lipids to form emulsified films decreases the water vapour transfer and could be used to encapsulate active substances or aroma compounds. The aim of this work was to measure permeability, sorption and diffusion coefficient of the n-hexanal and D-limonene aroma compounds through emulsified (wf) and non-emulsified (wof) i-carrageenan and sodium alginate-based films to finally…
Is Oxidative Stress the Link Between Cerebral Small Vessel Disease, Sleep Disruption, and Oligodendrocyte Dysfunction in the Onset of Alzheimer’s Dis…
2021
Oxidative stress is an early occurrence in the development of Alzheimer’s disease (AD) and one of its proposed etiologic hypotheses. There is sufficient experimental evidence supporting the theory that impaired antioxidant enzymatic activity and increased formation of reactive oxygen species (ROS) take place in this disease. However, the antioxidant treatments fail to stop its advancement. Its multifactorial condition and the diverse toxicological cascades that can be initiated by ROS could possibly explain this failure. Recently, it has been suggested that cerebral small vessel disease (CSVD) contributes to the onset of AD. Oxidative stress is a central hallmark of CSVD and is depicted as …