Search results for "IPA"

Application of molecular topology in the prediction of new compounds with anti-trypanosomal cytotoxic activity

2021

La enfermedad de Chagas es una antropozoonosis parasitaria de transmisión mayoritariamente vectorial. Si bien afecta principalmente a América, constituye una de las mayores enfermedades desatendidas a nivel mundial. Solamente dos fármacos con un alto grado de toxicidad se encuentran disponibles para su tratamiento, por lo que es preciso aunar esfuerzos en pos del desarrollo de nuevas drogas antitripanosomales eficaces y con escasos efectos adversos. En este estudio, se aplicó la topología molecular para el desarrollo de un modelo QSAR capaz de predecir la actividad citotóxica antitripanosomal de un grupo de 39 compuestos. El modelo desarrollado mediante análisis lineal discriminante permiti…

Promising trypanocidal heterocyclic compounds of natural origin and their synthetic analogs

2019

Abstract Diseases caused by members of the order Trypanosomatidae include human African trypanosomiasis (HAT) and Chagas disease, caused by species of Trypanosoma brucei and Trypanosoma cruzi, respectively, as well as leishmaniasis, caused by various species of Leishmania spp. These infections belong to the so-called neglected tropical diseases group, which are a diverse group of communicable diseases that prevail in tropical and subtropical conditions in 149 countries and affect more than one billion people in addition to costing developing economies billions of dollars every year. The available pharmacotherapies for combatting these diseases are limited and associated with strong side eff…

Synthesis and pharmacological evaluation of 2'-hydroxychalcones and flavones as inhibitors of inflammatory mediators generation.

1995

2'-Hydroxy-3,4-dimethoxy-3',4'-dimethylchalcone (3a), 2'-hydroxy-3',4',3,4-tetramethoxychalcone (3b), and their corresponding flavones, 3',4'-dimethoxy-7,8-dimethylflavone (4a) and 3',4',7,8-tetramethoxyflavone (4b), were prepared from 3,4-dimethoxycinnamic acid and the respective phenol. The four compounds inhibited enzymic lipid peroxidation and showed weak peroxyl scavenging activity. They also reduced LTB 4 release from human neutrophils stimulated by A23187. The chalcone 3b was the only compound able to inhibit in a concentration-dependent way, synovial human recombinant phospholipase A 2 activity, human platelet TXB 2 generation, and human neutrophil degranulation. This chalcone exert…

The profession’s proposals to the minister to prepare for climate change: what contributions from research to the strategy presented by the professio…

2021

Statistical properties of the capacity of multipath fading channels

2009

It is well known that a frequency-nonselective multipath fading channel can be modeled by a sum of complex sinusoids, also called sum-of-cisoids (SOC). By using the SOC, we can efficiently model the scattered component of the received signal in non-isotropic scattering environments. Such SOC-based multipath channel models provide the flexibility of having correlated in-phase and quadrature phase components of the received signal. This paper presents the derivation and analysis of the statistical properties of the capacity of multipath fading channels under LOS conditions. As an appropriate stochastic model for the multipath fading channel, we have adopted the SOC model. We have derived the …

Administrer une ville au XVIIIe siècle : Chartres

1988

International audience; Résumé À Chartres, au XVIIIème siècle, l'administration municipale est dominée par les officiersroyaux et par les marchands, qui en excluent progressivement les représentants du Chapitre cathédral.Le champ des responsabilités du Corps de ville est vaste : fiscalité, police municipale, logement dessoldats, fourniture de miliciens, voirie et urbanisme, eau, éclairage public, lutte contre les incendies,surveillance des marchés, fixation du prix du pain, enseignement, assistance aux pauvres, ... Ilspratiquent une politique prudente et raisonnable d'entretien du patrimoine, sans négliger pour autantd'utiles opérations d'urbanisme. Le budget reste remarquablement équilibré…

Perturbations of symmetric elliptic Hamiltonians of degree four

2006

AbstractIn this paper four-parameter unfoldings Xλ of symmetric elliptic Hamiltonians of degree four are studied. We prove that in a compact region of the period annulus of X0 the displacement function of Xλ is sign equivalent to its principal part, which is given by a family induced by a Chebychev system; and we describe the bifurcation diagram of Xλ in a full neighborhood of the origin in the parameter space, where at most two limit cycles can exist for the corresponding systems.

Mixed monolayers of natural and polymeric phospholipids: structural characterization by physical and enzymatic methods

1990

This study has focused on physical characterization and enzymatic hydrolysis of mixed monolayers of a natural phospholipid substrate and a polymerizable phospholipid analogue. Such a mixed system presents the possibility to stabilize model biomembranes, vary the molecular environment within the layer through polymerization and simultaneously examine these influences on monolayer structure. Phospholipase A2 was used here as a sensitive probe of the molecular environment within these mixed, polymerizable monolayers to complement information obtained from isotherm and isobar data. The results clearly show a strong influence of molecular environment on phospholipase A2 activity, even if differe…

Influence of lipid physical state on the in vitro digestibility of emulsified lipids.

2008

The objective of this study was to investigate the influence of the physical state of emulsified lipids on their in vitro digestibility by pancreatic lipase. A 10 wt % tripalmitin oil-in-water emulsion stabilized by sodium dodecyl sulfate (0.9 wt % SDS) was prepared at a temperature (>70 degrees C) above the melting point of the lipid phase (T(m) approximately 60 degrees C). A portion of this emulsion was cooled to a temperature (0 degrees C for 15 min) well below the crystallization temperature of the emulsified lipid (T(c) approximately 22 degrees C) and then warmed to 37 degrees C so as to have completely solid lipid particles. Another portion of the emulsion was directly cooled from 70 …

Flows and mixing in channels with misaligned superhydrophobic walls.

2014

Aligned superhydrophobic surfaces with the same texture orientation reduce drag in the channel and generate secondary flows transverse to the direction of the applied pressure gradient. Here we show that a transverse shear can be easily generated by using superhydrophobic channels with misaligned textured surfaces. We propose a general theoretical approach to quantify this transverse flow by introducing the concept of an effective shear tensor. To illustrate its use, we present approximate theoretical solutions and Dissipative Particle Dynamics simulations for striped superhydrophobic channels. Our results demonstrate that the transverse shear leads to complex flow patterns, which provide a…