Search results for "Interaction"

Regulatory effects of polyamines on membrane-bound acetylcholinesterase

1974

The effects of putrescene, spermidine and spermine on membrane-bound acetylcholinesterase from human erythrocyte ‘ghosts’ and the solubilized enzyme of the electric organ of the electric eel were studied by kinetic methods. Measurements were made by using a photometric method which made it possible to record the enzyme reaction in the steady-state phase. Substrate-concentration-dependent activation and inhibition of acetylcholinesterase by polyamines is similar to that by Na+, K+, Ca2+, Mg2+ and certain quaternary and bisquaternary amines. The kinetics suggest an allosteric reaction mechanism. On the basis of the kinetic results a role for the polyamines as modulators of synaptic acetylchol…

Teacher’s Verbal Communication in the Use of Reciprocal Teaching for Reading Comprehension: An Exploratory Study

2023

Nelle classi di scuola primaria delle tre ultime annualità, molti alunni hanno difficoltà a comprendere quello che leggono male, come si ricava dalla letteratura scientifica e dalle rilevazioni nazionali e internazionali. Il Reciprocal Teaching (RT) è una pratica di apprendimento cooperativo implementata con successo per sostenere e facilitare la comprensione del testo scritto. Alla ricerca hanno partecipato 10 insegnanti di scuola primaria, 73 alunni di classe quinta primaria hanno svolto un’attività di lettura guidata con il RT. Le interazioni verbali in classe sono state osservate; successivamente sono stati analizzati i protocolli raccolti durante le osservazioni nei gruppi per verifica…

Layout attributes and recall

2003

The spatial arrangement of elements such as icons in a computer interface may influence learning the interface. However, the effects of layout organization on users' information processing is relatively little studied so far. The three experiments of this paper examined two attributes of layouts: spatial grouping by proximity and semantic coherence. Learning was assessed by tasks in which 30 participants recalled icon-like items' labels, locations, or both as a series of study-recall trials. The results show that layout organization interacts with task demands. Semantic organization improves recall of labels, and spatial grouping supports recall of locations. When both labels and locations …

The Tobacco mosaic virus movement protein associates with but does not integrate into biological membranes

2014

Plant positive-strand RNA viruses require association with plant cell endomembranes for viral translation and replication, as well as for intra- and intercellular movement of the viral progeny. The membrane association and RNA binding of the Tobacco mosaic virus (TMV) movement protein (MP) are vital for orchestrating the macromolecular network required for virus movement. A previously proposed topological model suggests that TMV MP is an integral membrane protein with two putative -helical transmembrane (TM) segments. Here we tested this model using an experimental system that measured the efficiency with which natural polypeptide segments were inserted into the ER membrane under conditions…

Influence of PVP/VA copolymer composition on drug–polymer solubility

2015

In this study, the influence of copolymer composition on drug-polymer solubility was investigated. The solubility of the model drug celecoxib (CCX) in various polyvinylpyrrolidone/vinyl acetate (PVP/VA) copolymer compositions (70/30, 60/40, 50/50 and 30/70 w/w) and the pure homopolymers polyvinylpyrrolidone (PVP) and polyvinyl acetate (PVA) was predicted at 25 °C using a thermal analysis method based on the recrystallization of a supersaturated amorphous dispersion (recrystallization method). These solubilities were compared with a prediction based on the solubility of CCX in the liquid monomeric precursors of PVP/VA, N-vinylpyrrolidone (NVP) and vinyl acetate (VA), using the Flory-Huggins …

High-Generation Amphiphilic Janus-Dendrimers as Stabilizing Agents for Drug Suspensions

2018

Pharmaceutical nanosuspensions are formed when drug crystals are suspended in aqueous media in the presence of stabilizers. This technology offers a convenient way to enhance the dissolution of poorly water-soluble drug compounds. The stabilizers exert their action through electrostatic or steric interactions, however, the molecular requirements of stabilizing agents have not been studied extensively. Here, four structurally related amphiphilic Janus-dendrimers were synthesized and screened to determine the roles of different macromolecular domains on the stabilization of drug crystals. Physical interaction and nanomilling experiments have substantiated that Janus-dendrimers with fourth gen…

Reducing CAS-SDCI space. Using selected spaces in configuration interaction calculations in an efficient way

2002

A new method is presented, which allows an important reduction of the size of some Configuration Interaction (CI) matrices. Starting from a Complete Active Space (CAS), the numerous configurations that have a small weight in the CAS wave function are eliminated. When excited configurations (e.g., singly and doubly excited) are added to the reference space, the resulting MR-SDCI space is reduced in the same proportion as compared with the full CAS–SDCI. A set of active orbitals is chosen, but some selection of the most relevant excitations is performed because not all the possible excitations act as SDCI generators. Thanks to a new addressing technique, the computational time is drastically …

2019

Abstract This article considers the implementation of a new learning subject ”Technology Comprehension” into lower secondary schools in Denmark, as part of an initiative by the Danish Ministry of Education. The subject consists of learning objectives related to computing, design, and societal reflection and was first introduced as an elective course in 13 schools to investigate how it could be integrated into the Danish education system. We present four key findings based on school visits, interviews, an electronical survey, two questionnaires, and workshops including theme discussions: (1) teachers did not perceive Technology Comprehension as a distinct subject, but rather as a set of skil…

A new multimodal RGB and polarimetric image dataset for road scenes analysis

2020

International audience; Road scene analysis is a fundamental task for both autonomous vehicles and ADAS systems. Nowadays, one can find autonomous vehicles that are able to properly detect objects present in the scene in good weather conditions but some improvements are left to be done when the visibility is altered. People claim that using some non conventional sensors (infra-red, Lidar, etc.) along with classical vision enhances road scene analysis but still when conditions are optimal. In this work, we present the improvements achieved using polarimetric imaging in the complex situation of adverse weather conditions. This rich modality is known for its ability to describe an object not o…

Modelling the regenerative niche: a major challenge in biomaterials research

2015

By definition, biomaterials are developed for clinical application. In the field of regenerative medicine their principal function is to play a significant, and, if possible, an instructive role in tissue healing. In the last analysis the latter involves targeting the 'regenerative niche'. The present paper will address the problem of simulating this niche in the laboratory and adopts a life science approach involving the harnessing of heterotypic cellular communication to achieve this, that is, the ability of cells of different types to mutually influence cellular functions. Thus, co-culture systems using human cells are the methodological focus and will concern four exemplary fields of re…