Search results for "passive"
showing 10 items of 375 documents
A Proposed Methodology to Control Body Temperature in Patients at Risk of Hypothermia by means of Active Rewarming Systems
2014
Hypothermia is a common complication in patients undergoing surgery under general anesthesia. It has been noted that, during the first hour of surgery, the patient’s internal temperature (Tcore) decreases by 0.5–1.5°C due to the vasodilatory effect of anesthetic gases, which affect the body’s thermoregulatory system by inhibiting vasoconstriction. Thus a continuous check on patient temperature must be carried out. The currently most used methods to avoid hypothermia are based on passive systems (such as blankets reducing body heat loss) and on active ones (thermal blankets, electric or hot-water mattresses, forced hot air, warming lamps, etc.). Within a broader research upon the environment…
Passive Transport of Ionic Drugs through Membranes with pH-Dependent Fixed Charges
2001
We have studied both theoretically and experimentally the passive transport of ionic drugs through membranes with pH-dependent fixed charge. The system considered constitutes a simplified model for pH-controlled drug delivery through membranes of biochemical and pharmaceutical interest. The theoretical approach employed is based on the Nernst-Planck flux equations and all of the species present in the system (the neutral or ionic drug and the hydrogen and hydroxide ions) have been taken into account together with a Langmuir-type isotherm for the adsorption of the ionic drug onto the membrane surface. The membrane permeabilities of cationic, anionic, and neutral drugs through porous membrane…
Determinants of self-reported smoking and misclassification during pregnancy, and analysis of optimal cut-off points for urinary cotinine: a cross-se…
2013
10 p. Objectives: To estimate the prevalence and factors associated with smoking and misclassification in pregnant women from INMA (INfancia y Medio Ambiente, Environment and Childhood) project, Spain, and to assess the optimal cut-offs for urinary cotinine (UC) that best distinguish daily and occasional smokers with varying levels of second-hand smoke (SHS) exposure.-- Design: We used logistic regression models to study the relationship between sociodemographic variables and self-reported smoking and misclassification (self-reported non-smokers with UC >50 ng/ml). Receiver operating characteristic (ROC) curves were used to calculate the optimal cut-off point for discriminating smokers. The…
Design of Implanted RFID Tags for Passive Sensing of Human Body: The STENTag
2012
Numerical processing of passive UHF-RFID tags' response may provide physical insight about the hosting object or about the nearby environment. This idea is here extended to implanted antennas with the purpose to sense the evolution of some human physiological and pathological process involving a local change of effective permittivity inside the body. The goal is to understand how master the design of this class of devices taking into account both communication and sensing capabilities. An ad hoc design methodology is here presented and discussed by means of a realistic medical case concerning the modification of an endo-vascular device to achieve a STENTag able to sense the state of the ves…
Retention-activity relationship studies of benzodiazepines by micellar liquid chromatography
1999
Solute partitioning into lipid bilayers of biological membranes is the basis for drug and metabolite uptake, passive transport across membranes and bioaccumulation. In order to emulate in vitro the partitioning process in the biomembranes, different approaches have been proposed. The use of micellar solutions as mobile phases in reversed-phase liquid chromatography (micellar liquid chromatography, MLC) has proven to be valid in the prediction of the biological activities of local anesthetics, catecholamines and barbiturates. In this paper we focus our attention on benzodiazepines. The retention of benzodiazepines using different concentrations of Brij35 as micellar mobile phase in modified …
Development of predictive retention-activity relationship models of antipsychotic drugs by micellar liquid chromatography
1999
The predictive and interpretative capability of quantitative chromatographic retention-biological activity models is supported by the fact that in adequate experimental conditions the solute partitioning into the chromatographic system can emulate the solute partitioning into lipid bilayers of biological membranes, which is the basis of drug and metabolite uptake, passive transport across membranes and bioaocumulation. The use of micellar solutions of Brij35 as mobile phases in reversed liquid chromatography has proven to be valid in predicting some biological activities of different kinds of drugs. In this paper, the correlations between the logarithm of capacity factors and pharmacokineti…
Medidas de Tromboprofilaxis en Artroplastia Total de Rodilla. Práctica habitual en la Comunidad Valenciana y revisión bibliográfica.
2020
espanolAntecedentes: El tromboembolismo es una complicacion de la cirugia de artroplastia total de rodilla. Para su prevencion disponemos de multiples medidas fisicas y farmacologicas.Objetivo:Conocer quemedidas de prevencion tromboembolica son las empleadas por los cirujanos ortopedicos en cirugia protesica de rodilla primaria en diferentes centros hospitalarios de nuestra region.Metodo: Estudio transversal descriptivo observacional basado en encuesta dirigida a especialistas COT de 9 hospitales publicos de la Comunidad Valenciana y busqueda bibliografica.Resultados: Se obtuvieron 64 encuestas. Todos los cirujanos eligen HBPM durante un mes como medida de tromboprofilaxis, descartando anti…
Development of predictive retention-activity models of butyrophenones by biopartitioning micellar chromatography
2001
The predictive and interpretative capability of quantitative chromatographic retention-biological activity models is supported by the fact that in adequate experimental conditions the solute partitioning into the chromatographic system can emulate the solute partitioning into lipid bilayers of biological membranes, which is the basis of drug and metabolite uptake, passive transport across membranes and bioaccumulation. The use of retention data obtained in biopartitioning micellar chromatography (BMC) has been demonstrated to be helpful in describing the biological behaviour of different kinds of drugs. In this chromatographic system, polioxyethylene 23 lauryl ether Brij35 micellar mobile p…
Development of Predictive Retention-Activity Relationship Models of Barbiturates by Micellar Liquid Chromatography
2000
The need to get a tool for biological parameters estimation of new compounds for clinical applications, supports the postulation of predictive models as an alternative to conventional classical assays being no necessary the use of experimentation in animals. Our main aim in this work is to determine correlations between the logarithm of capacity factors and preclinical pharmacology and therapeutic efficacy parameters of barbiturates. The predictive and interpretative capability of quantitative chromatographic retention-biological activity models is supported by the fact that in adequate experimental conditions the solute partitioning into chromatographic system can emulate the solute partit…
Influences of Structure and Composition on the Photoelectrochemical Behaviour of Anodic Films on Zr and Zr-20at.%Ti
2008
Abstract A photoelectrochemical investigation on anodic films of different thickness grown on sputter-deposited Zr and Zr–20 at.%Ti was carried out. The estimated optical band gap and flat band potential of thick ( U F ≥ 50 V) anodic films were related to their crystalline structure and compared with those obtained for thinner ( U F ≤ 8 V/SCE) anodic oxides having undetermined crystalline structure. The E g values obtained by photocurrent spectroscopy were also compared with the experimental band gap estimated by other optical ex situ techniques and with the available theoretical estimates of the zirconia electronic structures in an attempt to reconcile the wide range of band gap data rep…