Search results for "Pore"
showing 10 items of 929 documents
Polymer translocation through a nanopore induced by adsorption: Monte Carlo simulation of a coarse-grained model
2004
Dynamic Monte Carlo simulation of a bead-spring model of flexible macromolecules threading through a very narrow pore in a very thin rigid membrane are presented, assuming at the cis side of the membrane a purely repulsive monomer-wall interaction, while the trans side is attractive. Two choices of monomer-wall attraction epsilon are considered, one choice is slightly below and the other slightly above the "mushroom to pancake" adsorption threshold epsilon(c) for an infinitely long chain. Studying chain lengths N=32, 64, 128, and 256 and varying the number of monomers N(trans) (time t=0) that have already passed the pore when the simulation started, over a wide range, we find for epsiloneps…
Mitochondrial oxidative stress and CD95 ligand: A dual mechanism for hepatocyte apoptosis in chronic alcoholism
2002
Apoptosis plays an important role in the progression of alcohol-induced liver disease to cirrhosis. Oxidative stress is an early event in the development of apoptosis. The major aim of this study was to study the conditions in which oxidative stress occurs in chronic alcoholism and its relationship with apoptosis of hepatocytes. We have found that oxidative stress is associated with chronic ethanol consumption in humans and in rats, in the former independently of the existence of alcohol-induced liver disease. Ethanol or acetaldehyde induces apoptosis in hepatocytes isolated from alcoholic rats, but not in those from control rats. Inhibition of aldehyde dehydrogenase, but not of cytochrome …
The Relationship between Alcohol–induced Apoptosis and Oxidative Stress in the Liver
2005
This chapter discusses the relationship of apoptosis and oxidative stress induced by alcohol in the liver. Oxidative stress is involved in the pathogenesis and progression of alcohol-induced liver disease. Chronic alcoholism always causes oxidative stress independently of the presence of liver disease. Two key mechanisms are responsible for it: (1) the mitochondrial respiratory chain and (2) cytochrome P450 2El activity. Increased production of reactive oxygen species at complexes I and III together with NADH overproduction would be the major cause for mitochondrial oxidative stress in chronic alcoholism. Reactive Oxygen Species (ROS) cause oxidative damage, which may lead to cell death by …
Impact of surface state on polyethylene glycol conformation confined inside a nanopore.
2021
Solid-state nanopores are a promising platform for characterizing proteins. In order to improve their lifetime and prevent fouling, Polyethylene Glycol (PEG) grafting is one of the most efficient and low-cost solutions. Different models to calculate the PEG thickness do not consider their interaction with the nanopore inner surface nor the effect of confinement. Here, we investigate by molecular dynamic simulation the PEG conformation inside a nanopore in the case of hydrophobic and hydrophilic nanopores. Our results reveal that the nanopore inner surface plays a role in the PEG organization and, thus, in the speed of the salt constituent. The resulting pair interaction between PEG and its …
Oxygen Radical Scavengers
2010
The myocardium can tolerate only relatively short periods of total myocardial ischemia without myocardial cell death. Following short ischemic periods, ischemic damage is reversible by reperfusion. However, with increasing duration and severity of ischemia, the damage inflicted to cardiomyocytes following reperfusion becomes irreversible. The combined pathologic events in the myocardium that follow a critical period of ischemia and leading to either reversible or irreversible damage to both cardiomyocytes and cardiac microvasculature is known as ischemia-reperfusion injury (Goldhaber and Weiss 1992).
Comunicare con i bambini per promuovere la loro crescita la prospettiva intersoggettiva ed embodied
2020
L'articolo tratta della specificità della relazione adulto-bambino piccolo, soffermandosi sulla prospettiva intersoggettiva alla seconda persona e facendo riferimento alle ultime ricerche neuroscientifiche che confermano il ruolo fondamentale della comunicazione psico-corporea nell'apprendimento e nello sviluppo infantile e l’importanza delle emozioni e degli affetti. Riflette quindi sulla specificità dei percorsi formativi per gli educatori per l’infanzia che, in una tale prospettiva, dovrebbero intrecciare il piano personale e quello professionale centrandosi sull’esperienza e sulla riflessione e l’autoriflessione. In questo senso particolarmente efficaci si rivelano i linguaggi artistico…
Quando la chirurgia estetica diventa teen
2014
La ricerca si pone l’obiettivo di indagare alcune variabili psicosociali ritenute dalla letteratura sull’argomento elementi importanti dell’interesse per la chirurgia estetica, come la percezione corporea e l’Ego-resiliency, in un gruppo di 210 adolescenti e giovani donne del territorio paler-mitano. I dati mostrano come la percezione di sé abbia un ruolo centrale, essendo l’unica variabile tra quelle indagate che influisce sull’interesse per la chirurgia estetica. Inoltre, l’Ego-resiliency, ossia la capacità di gestire in modo flessibile i propri impulsi e le proprie emozioni e di adattarsi efficacemente alle richieste dell’ambiente, è fortemente legato alla percezione di sé, che, a sua vo…
Etude de la variable fiscale comme facteur de contingence dans la reconnaissance des immobilisations incorporelles
1999
International audience; En pratique, la rubrique "immobilisations incorporelles" pèse peu lourd dans le bilan des comptes sociaux des entreprises françaises. L'un des facteurs explicatifs peut être l'existence de liens théoriques entre la comptabilité et la fiscalité; cette existence conduit, en effet, à une pratique fiscalo-comptable des entreprises en matière de choix comptables ou d'amortissement du fonds de commerce. Cette influence de la variable fiscale sur le traitement comptable des éléments incorporels pose d'ailleurs problème dans le cadre du processus de normalisation internationale.
The RIBES strategy for ex situ conservation: conventional and modern techniques for seed conservation
2022
The Italian seed bank network (RIBES) aims to improve the quality and safety of the germplasm reserves of native plant species in Italy to ensure the long-term conservation of endangered and/or endemic flora. The strategy includes traditional methods to secure seed conservation. A comprehensive priority list for seed collection is being defined, it was prepared by crossing data of various checklists (red lists, endemics) and will soon be cross-referenced with an updated list of accessions of the whole network. A safety-backup program of duplicates will quickly be implemented to secure the conservation of the most threatened species in at least two seed banks of the network. On the other han…
Computational methods and theory for ion channel research
2022
Ion channels are fundamental biological devices that act as gates in order to ensure selective ion transport across cellular membranes; their operation constitutes the molecular mechanism through which basic biological functions, such as nerve signal transmission and muscle contraction, are carried out. Here, we review recent results in the field of computational research on ion channels, covering theoretical advances, state-of-the-art simulation approaches, and frontline modeling techniques. We also report on few selected applications of continuum and atomistic methods to characterize the mechanisms of permeation, selectivity, and gating in biological and model channels.