Search results for " Gradient"
showing 10 items of 575 documents
A 66-kilodalton heat shock protein of Salmonella typhimurium is responsible for binding of the bacterium to intestinal mucus
1992
Salmonella typhimurium infections have increased during the last few years. However, the interplay of virulence factors in S. typhimurium pathogenesis is still poorly understood, particularly with regard to the mechanisms and components of the bacterium which are involved in its interaction with the intestinal mucus. We have observed that S. typhimurium is aggregated by incubation with colonic mucus (guinea pig model). To quantify this phenomenon, an aggregation assay was established. By using this assay, it was found that the aggregation profile of S. typhimurium strains freshly isolated from patients (age 9 and older) with salmonellosis correlated with the severity of the disease. An isol…
Low-density lipoproteins generated during an oral fat load in mild hypertriglyceridemic and healthy subjects are smaller, denser, and have an increas…
2005
Triglyceride-rich lipoproteins generated during the postprandial phase are atherogenic. Large very low-density lipoproteins (LDLs) or chylomicrons (CMs) are not as atherogenic as their remnants (Rem). Small and dense LDLs are associated with cardiovascular disease. Low-density lipoprotein size is partly under genetic control and is considered as a relatively stable LDL feature. In this article, we present data on retinyl palmitate kinetics correlated with the modification of LDL features in terms of size, density, and in vitro receptor binding affinity after an oral fat load. Six nondiabetic, hypertriglyceridemic (HTG) patients and 6 healthy controls were examined. Low-density lipoprotein s…
Prevalence of Parental Alcohol Problems among a General Population Sample of 28,047 Norwegian Adults: Evidence for a Socioeconomic Gradient
2021
The aim of the study presented here was to estimate the prevalence of parental alcohol problems during childhood in a general population of Norwegian adults, and to investigate associations between parental alcohol problems during childhood and lower socioeconomic status in adulthood. This cross-sectional study recruited 28,047 adults (≥18 years) to an online health survey (Norwegian Counties Public Health Surveys). We evaluated demographic and socioeconomic measures and responses to a shortened version of the Children of Alcoholics Screening Test (CAST-6) scale to assess whether respondents perceived parental alcohol consumption during childhood as problematic. Respondents reported parenta…
Practical strategies for stable operation of HFF-QCM in continuous air flow
2013
Currently there are a few fields of application using quartz crystal microbalances (QCM). Because of environmental conditions and insufficient resolution of the microbalance, chemical sensing of volatile organic compounds in an open system was as yet not possible. In this study we present strategies on how to use 195 MHz fundamental quartz resonators for a mobile sensor platform to detect airborne analytes. Commonly the use of devices with a resonant frequency of about 10 MHz is standard. By increasing the frequency to 195 MHz the frequency shift increases by a factor of almost 400. Unfortunately, such kinds of quartz crystals tend to exhibit some challenges to obtain a reasonable signal-to…
A new method to isolate lichen algae by using percoll® gradient centrifugation
2001
AbstractA rapid method to isolate intact functional algae from the lichens Evemia prunastri and Ramalina farinacea has been developed. This method is based on the use of Percoll® gradients after mechanical disruption of lichen thalli. Results obtained show that the algal preparations were virtually free of contamination by fungal hyphae. The purified algal cells were photosynthetically active and without symptoms of photoinhibition, which indicates their functional integrity. This method may be used for the isolation of intact algae from a broad range of lichen species.
The hydrothermal system of the Domuyo volcanic complex (Argentina): A conceptual model based on new geochemical and isotopic evidences
2016
The Domuyo volcanic complex (Neuquén Province, Argentina) hosts one of the most promising geothermal systems of Patagonia, giving rise to thermal manifestations discharging hot and Cl−-rich fluids. This study reports a complete geochemical dataset of gas and water samples collected in three years (2013, 2014 and 2015) from the main fluid discharges of this area. The chemical and isotopic composition (δD-H2O and δ18O-H2O) of waters indicates that rainwater and snow melting are the primary recharge of a hydrothermal reservoir located at relative shallow depth (400–600 m) possibly connected to a second deeper (2–3 km) reservoir. Reactive magmatic gases are completely scrubbed by the hydrotherm…
On a global superconvergence of the gradient of linear triangular elements
1987
Abstract We study a simple superconvergent scheme which recovers the gradient when solving a second-order elliptic problem in the plane by the usual linear elements. The recovered gradient globally approximates the true gradient even by one order of accuracy higher in the L 2 -norm than the piecewise constant gradient of the Ritz—Galerkin solution. A superconvergent approximation to the boundary flux is presented as well.
Facilitated SLM extraction of peptides with D2EHPA as a carrier
2004
Abstract The extraction of short peptides through a supported liquid membrane containing di-2-(ethylhexyl)phosphoric acid (D2EHPA) as a carrier was investigated. The extraction was carried out from the aqueous donor phase with pH 3 to amore acidic acceptor phase. The proton gradient between the donor and the acceptor phase was the main driving force of the mass transfer in this system. The influence of various parameters such as diluent of the carrier, pH of the donor and acceptor phase, peptide structure and concentration on the extraction efficiency was presented.
Study of uniformity of plasmas produced in a wall-stabilized arc
2003
In this contribution the plasma of an arc discharge in a mixture of helium and argon is studied. The gas mixture is introduced uniformly along the arc column between each of the stabilizing plates. From the measured lateral distribution of radiation (HeI, HI, ArI, ArII, NI, FI line intensity and width measurements), after Abel inversion, the radial temperature distributions were obtained at various positions of the arc column. Beside the expected radial temperature gradients, a distinct temperature gradient along the arc column was found.
Estimation of Granger causality through Artificial Neural Networks: applications to physiological systems and chaotic electronic oscillators
2021
One of the most challenging problems in the study of complex dynamical systems is to find the statistical interdependencies among the system components. Granger causality (GC) represents one of the most employed approaches, based on modeling the system dynamics with a linear vector autoregressive (VAR) model and on evaluating the information flow between two processes in terms of prediction error variances. In its most advanced setting, GC analysis is performed through a state-space (SS) representation of the VAR model that allows to compute both conditional and unconditional forms of GC by solving only one regression problem. While this problem is typically solved through Ordinary Least Sq…