Search results for "Models"
showing 10 items of 8211 documents
Experimental Studies on the Influence of Surfactants on Intestinal Absorption of Drugs Cefadroxil as model drug and sodium taurocholate as natural mo…
2011
The influence of the natural bile acid surfactant sodium taurocholate (CAS 81-24-3) on colic and duodenal (i.e. the proximal third of the small intestine) absorption of cefadroxil (CAS 50370-12-2) was studied using the in situ rat gut technique, and compared with the effect of sodium lauryl sulfate (CAS 151-21-3), the most widely used synthetic anionic surfactant. Previously, the stability, compatibility, and micelle-solubilization characteristics of taurocholate were assessed in order to correct, when necessary, the absorption results. White the passive absorption rate constants (kf, h-1) determined in colon in the presence of increasing lauryl sulfate concentrations showed an asymptotic v…
Position paper - progress towards standards in integrated (aerobic) MBR modelling.
2020
Membrane bioreactor (MBR) models are useful tools for both design and management. The system complexity is high due to the involved number of processes which can be clustered in biological and physical ones. Literature studies are present and need to be harmonized in order to gain insights from the different studies and allow system optimization by applying a control. This position paper aims at defining the current state of the art of the main integrated MBR models reported in the literature. On the basis of a modelling review, a standardized terminology is proposed to facilitate the further development and comparison of integrated membrane fouling models for aerobic MBRs. ispartof: WATER …
ETAS Space–Time Modeling of Chile Triggered Seismicity Using Covariates: Some Preliminary Results
2021
Chilean seismic activity is one of the strongest in the world. As already shown in previous papers, seismic activity can be usefully described by a space–time branching process, such as the ETAS (Epidemic Type Aftershock Sequences) model, which is a semiparametric model with a large time-scale component for the background seismicity and a small time-scale component for the triggered seismicity. The use of covariates can improve the description of triggered seismicity in the ETAS model, so in this paper, we study the Chilean seismicity separately for the North and South area, using some GPS-related data observed together with ordinary catalog data. Our results show evidence that the use of s…
Design and implementation of modelling tasks using iPad's: a dual perspective
2016
[EN] This paper presents the design of two experiences to introduce modelling of physical phe-nomena through modelling tasks using iPadR's. Each of the proposals is designed with adi erent vision about modelling. In one case modelling is used as a vehicle to introduceprecise mathematical contents. While, on the other one, we intend to develop an activitythat can help student to improve their modelling competence. Our aim is to present twoproposals to introduce modelling in a ninth or tenth grade classroom
Differential evolution of PSA-NCAM expression during aging of the rat telencephalon
2007
Changes in the ability of neuronal networks to undergo structural remodeling may be involved in the age-associated cognitive decline. The polysialylated form of the neural cell adhesion molecule (PSA-NCAM) declines dramatically during postnatal development, but persists in several regions of the young-adult rat telencephalon, where it participates, through its anti-adhesive properties, in neuronal structural plasticity. However, PSA-NCAM expression during aging has only been studied in the dentate gyrus and the piriform cortex layer II, where it is strongly downregulated in adult (middle-aged) individuals. Using immunohistochemistry, we have observed that in most of the telencephalic areas …
Association of basal forebrain volumes and cognition in normal aging.
2013
The basal forebrain cholinergic system (BFCS) is known to undergo moderate neurodegenerative alterations during normal aging and severe atrophy in Alzheimer's disease (AD). It has been suggested that functional and structural alterations of the BFCS mediate cognitive performance in normal aging and AD. But, it is still unclear to what extend age-associated cognitive decline can be related to BFCS in normal aging. We analyzed the relationship between BFCS volume and cognition using MRI and a comprehensive neuropsychological test battery in a cohort of 43 healthy elderly subjects spanning the age range from 60 to 85 years. Most notably, we found significant associations between general intell…
Chromatin modifiers and recombination factors promote a telomere fold-back structure, that is lost during replicative senescence.
2020
Telomeres have the ability to adopt a lariat conformation and hence, engage in long and short distance intra-chromosome interactions. Budding yeast telomeres were proposed to fold back into subtelomeric regions, but a robust assay to quantitatively characterize this structure has been lacking. Therefore, it is not well understood how the interactions between telomeres and non-telomeric regions are established and regulated. We employ a telomere chromosome conformation capture (Telo-3C) approach to directly analyze telomere folding and its maintenance in S. cerevisiae. We identify the histone modifiers Sir2, Sin3 and Set2 as critical regulators for telomere folding, which suggests that a dis…
Croissance et convergence des pays de la zone CFA : une étude par les données de panel non stationnaires
2011
During the recent years, african countries in the CFA zone have experienced many economic changes on the one hand through the measures initiated by bilateral and multilateral donors and on the other hand through the economic and monetary integration policies. Thus, relying on the assumption that because of these interventions, the economic systems incorporate various phenomena such as structural change and economic interdependencies, we studied their major implications on growth, convergence and growth predictability. Emphasis is first placed on the major features of integration policies in a monetary union, while stressing the possible implications of such policies on the economic dynamics…
The role of the dual nature of ionic liquids in the reversed-phase liquid chromatographic separation of basic drugs.
2010
The cationic nature of basic drugs gives rise to broad asymmetrical chromatographic peaks with conventional C18 columns and hydro-organic mixtures, due to the ionic interaction of the positively charged solutes with the free silanol groups on the alkyl-bonded reversed-phase packing. Ionic liquids (ILs) have recently attracted some attention to reduce this undesirable silanol activity. ILs are dual modifiers (with a cationic and anionic character), which means that both cation and anion can be adsorbed on the stationary phase, giving rise to interesting interactions with the anionic free silanols and the cationic basic drugs. A comparative study of the performance of four imidazolium-based I…
Synaptic tetraspan vesicle membrane proteins are conserved but not needed for synaptogenesis and neuronal function in Caenorhabditis elegans
2006
Tetraspan vesicle membrane proteins (TVPs) comprise a major portion of synaptic vesicle proteins, yet their contribution to the synaptic vesicle cycle is poorly understood. TVPs are grouped in three mammalian gene families: physins, gyrins, and secretory carrier-associated membrane proteins (SCAMPs). In Caenorhabditis elegans , only a single member of each of these families exists. These three nematode TVPs colocalize to the same vesicular compartment when expressed in mammalian cells, suggesting that they could serve overlapping functions. To examine their function, C. elegans null mutants were isolated for each gene, and a triple mutant was generated. Surprisingly, these animals develop …