Search results for "Conducta"
showing 10 items of 611 documents
Interaction of Heparins and Dextran Sulfates with a Mesoscopic Protein Nanopore
2009
A mechanism of how polyanions influence the channel formed by Staphylococcus aureus alpha-hemolysin is described. We demonstrate that the probability of several types of polyanions to block the ion channel depends on the presence of divalent cations and the polyanion molecular weight and concentration. For heparins, a 10-fold increase in molecular weight decreases the half-maximal inhibitory concentration, IC(50), nearly 10(4)-fold. Dextran sulfates were less effective at blocking the channel. The polyanions are significantly more effective at reducing the conductance when added to the trans side of this channel. Lastly, the effectiveness of heparins on the channel conductance correlated wi…
Cluster organization and pore structure of ion channels formed by beticolin 3, a nonpeptidic fungal toxin
1999
Beticolin 3 (B3) belongs to a family of nonpeptidic phytotoxins produced by the fungus Cercospora beticola, which present a broad spectrum of cytotoxic effects. We report here that, at cytotoxic concentration (10 microM), B3 formed voltage-independent, weakly selective ion channels with multiple conductance levels in planar lipid bilayers. In symmetrical standard solutions, conductance values of the first levels were, respectively, 16 +/- 1 pS, 32 +/- 2 pS, and 57 +/- 2 pS (n = 4) and so on, any conductance level being roughly twice the lower one. Whether a cluster organization of elementary channels or different channel structures underlies this particular property was addressed by investi…
Entropy–enthalpy compensation at the single protein level: pH sensing in the bacterial channel OmpF
2014
The pH sensing mechanism of the OmpF channel operates via ligand modification: increasing acidity induces the replacement of cations with protons in critical binding sites decreasing the channel conductance. Aside from the change in enthalpy associated with the binding, there is also a change in the microscopic arrangements of ligands, receptors and the surrounding solvent. We show that the pH-modulation of the single channel conduction involves small free energy changes because large enthalpic and entropic contributions change in opposite ways, demonstrating an approximate enthalpy–entropy compensation for different salts and concentrations. We wish to acknowledge the support from the Span…
Implementation of Online Behavior Modification Techniques in the Management of Chronic Musculoskeletal Pain: A Systematic Review and Meta-Analysis
2022
Purpose: The main aim of this systematic review and meta-analysis (MA) was to assess the effectiveness of online behavior modification techniques (e-BMT) in the management of chronic musculoskeletal pain. Methods: We conducted a search of Medline (PubMed), Cumulative Index to Nursing and Allied Health Literature (CINAHL), Web of Science, APA PsychInfo, and Psychological and Behavioral Collections, from inception to the 30 August 2021. The main outcome measures were pain intensity, pain interference, kinesiophobia, pain catastrophizing and self-efficacy. The statistical analysis was conducted using RStudio software. To compare the outcomes reported by the studies, we calculated the standardi…
Bɪ-CомDᴇт: Community Detection in Bipartite Networks
2019
Abstract Extracting hidden communities from bipartite networks witnessed a determined effort. In this respect, different streams of research relied on bipartite networks to unveil communities. In this paper, we introduce a new approach, called Bi-Comdet, that aims to an efficient community detection in bipartite networks. The main trust of the introduced approach is that it stresses on the importance of grouping two types of nodes in communities having a full connection between its nodes. The quality of the unveiled communities, is assessed through some metrics borrowed from the FCA community, to wit modularity, overlapping and stability. These metrics are then aggregated through the use of…
Cooperative Effects Enhance Electric-Field-Induced Conductance Switching in Molecular Monolayers
2011
The anchoring of molecules with functional groups at surfaces permits information processing based on two stable molecular states that can be tuned externally by light irradiation and external fields. By using a molecular model that incorporates the essential characteristics of the problem, we show that the local interactions between adjacent molecules in a densely packed monolayer can stabilize domains with the same molecular state because of cooperative processes, enhancing significantly the switching properties between the molecular states. The case of electric-field-induced conductance switching is exploited in two possible applications: the design of a logic gates system and the operat…
Metallic Nanoparticles Linked to Molecular Switches as Signal Processing Devices
2009
We explore theoretically the use of nanoscale switches whose conductance can be varied between two states by an external stimulus to implement signal processing devices. The building block is formed by a metallic nanoparticle linked to two electrodes by an organic ligand and a molecular switch. The system implementation exploits the sharp current resonance of the system that occurs when the frequencies of the applied potential and the induced variation on the switch conductance coincide.
Device variability and circuit redundancy in signal processing based on nanoswitches
2009
Signal processing based on molecular switches whose conductance can be tuned by an external stimulus between two (on and off) states has been proposed recently (Cervera et al 2008 J. Appl. Phys. 104 084317). The basic building block is a metal nanoparticle linked to two electrodes by an organic ligand and a nanoswitch. The net charge delivered by this nanostructure exhibits a sharp resonance when the alternating potential applied between the electrodes has the same frequency as the periodic variation between the on and off conductance states induced on the nanoswitch. This resonance can be used to process an external signal by selectively extracting the weight of the different harmonics. Ho…
Cinema Data Mining
2015
While the physiological response of humans to emotional events or stimuli is well-investigated for many modalities (like EEG, skin resistance, ...), surprisingly little is known about the exhalation of so-called Volatile Organic Compounds (VOCs) at quite low concentrations in response to such stimuli. VOCs are molecules of relatively small mass that quickly evaporate or sublimate and can be detected in the air that surrounds us. The paper introduces a new field of application for data mining, where trace gas responses of people reacting on-line to films shown in cinemas (or movie theaters) are related to the semantic content of the films themselves. To do so, we measured the VOCs from a mov…
ESE. Estudios sobre educación
2021
espanolEste estudio pretende avanzar en la comprension de la relacion entre el profesor y el estudiante universitario con el objetivo de mejorar el rendimiento de los estudiantes. Se articula sobre tres ejes: el enfoque de rendimiento del estudiante, la relacion entre diversos aspectos del profesor y, fi nalmente, el efecto de estos aspectos sobre el rendimiento del estudiante. Los resultados obtenidos de una muestra de 45 profesores y 932 estudiantes muestran que la orientacion al estudiante por parte del profesor afecta al aprendizaje percibido y a la satisfaccion del estudiante. Se alcanzan otros interesantes resultados que permiten establecer ciertas conclusiones e implicaciones. Englis…