Length-scale dependent relaxation shear modulus and viscoelastic hydrodynamic interactions in polymer liquids.

A quantitative theory of hydrodynamic interactions in unentangled polymer melts and concentrated solutions is presented. The study is focussed on the pre-Rouse transient time regimes (t < τ(R), the Rouse relaxation time) where the hydrodynamic response is governed mainly by the viscoelastic effects. It is shown that transient viscoelastic hydrodynamic interactions are not suppressed (screened) at large distances and are virtually independent of polymer molecular mass.

Hydrodynamic and viscoelastic effects in polymer diffusion.

We develop a fluctuating hydrodynamics approach to study the impact of the hydrodynamic and viscoelastic interactions on the motion of the center of mass of a polymer as well as on the relaxation of Rouse modes, either in a Θ solvent or in a melt of identical unentangled chains. We show that this method allows us to describe the effect of hydrodynamic interactions beyond the Zimm (for a single chain in a Θ solvent) or the Rouse models (for an unentangled melt). In the latter case, we recover the same important effect of the viscoelastic hydrodynamic interactions on the center-of-mass diffusion, first described in Farago et al (2011 Phys.

PHBV/PCL microparticles for controlled release of resveratrol: physicochemical characterization, antioxidant potential, and effect on hemolysis of human erythrocytes.

Microparticles of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and poly(ε-caprolactone) (PCL) containing resveratrol were successfully prepared by simple emulsion/solvent evaporation. All formulations showed suitable encapsulation efficiency values higher than 80%. PHBV microparticles revealed spherical shape with rough surface and presence of pores.

Headache in patients with idiopathic intracranial hypertension: a pilot study to assess applicability of ICHD-2 diagnostic criteria.

Headache is one of the most common symptoms of idiopathic intracranial hypertension (IIH). The aim of this study was to investigate the applicability of the diagnostic criteria for "Headache attributed to IIH" included in the current classification of headache disorders, particularly as far as the main headache features. A consecutive clinical series of IIH patients with demonstration of increased intracranial pressure by lumbar puncture in the recumbent position were enrolled.

In Vitro Cytotoxic Potential of Essential Oils of Eucalyptus benthamii and Its Related Terpenes on Tumor Cell Lines.

Eucalyptus L. is traditionally used for many medicinal purposes. In particular, some Eucalyptus species have currently shown cytotoxic properties.

BRCT domains: A little more than kin, and less than kind.

BRCT domains are versatile protein modular domains found as single units or as multiple copies in more than 20 different proteins in the human genome. Interestingly, most BRCT-containing proteins function in the same biological process, the DNA damage response network, but show specificity in their molecular interactions. BRCT domains have been found to bind a wide array of ligands from proteins, phosphorylated linear motifs, and DNA.

[The phenomenon of drug change in the interviews with injecting drug users].

Introduction: Important part of the studies on drug use deals with drug use transitions because of their public health consequences. Narrating of drug use change states the active decision making in the centre of the process with adding mental states of the participants to the change process. The transitional narratives can be embedded in the social context of "risk environment".

Hierarchical self-organization of cytoskeletal active networks.

The structural reorganization of the actin cytoskeleton is facilitated through the action of motor proteins that crosslink the actin filaments and transport them relative to each other. Here, we present a combined experimental-computational study that probes the dynamic evolution of mixtures of actin filaments and clusters of myosin motors. While on small spatial and temporal scales the system behaves in a very noisy manner, on larger scales it evolves into several well distinct patterns such as bundles, asters and networks.

Duty ratio of cooperative molecular motors.

Molecular motors are found throughout the cells of the human body and have many different and important roles. These micromachines move along filament tracks and have the ability to convert chemical energy into mechanical work that powers cellular motility. Different types of motors are characterized by different duty ratios, which is the fraction of time that a motor is attached to its filament.

Dental caries experience in a Hungarian police student population.

The aim of this study was to assess the caries experience of Hungarian police students and to evaluate its relationship with nutrition, oral hygiene habits, behavioural and social factors. This representative cross-sectional epidemiological survey was conducted in a dental office of the Miskolc Law Enforcement Secondary School in Hungary in 2008. Altogether 792 Hungarian police student volunteers (male/female ratio was 90.

Mechanical surface tension governs membrane thermal fluctuations.

We use analytical considerations and computer simulations to show that the membrane spectrum of thermal fluctuations is governed by the mechanical and not the intrinsic tension. Our study highlights the fact that the commonly used quadratic approximation of the Helfrich effective Hamiltonian is not rotationally invariant. We demonstrate that this nonphysical feature leads to a calculated mechanical tension that differs dramatically from the correct mechanical tension.

Entropic attraction of adhesion bonds toward cell boundaries.

Adhesion bonds between membranes and surfaces are attracted to each other via effective interactions whose origin is the entropy loss due to the reduction in the amplitude of the membrane thermal fluctuations in the vicinity of the adhesion bonds. These fluctuation-induced interactions are also expected to drive the adhesion bonds toward the rim of the cell as well as toward the surfaces of membrane inclusions. In this paper we analyze the attraction of adhesion bonds to the cell inner and outer boundaries.

Purification of high-quality micro RNA from the heart tissue.

Micro RNAs (miRNA) are an abundant class of small RNAs that regulate the stability and translation of cognate mRNAs. MiRNAs are potential diagnostic markers, moreover, they play an essential role in the development of various heart disesases. In case of limited tissue material, such as, e.

Anomalous diffusion of a polymer chain in an unentangled melt.

Contrary to common belief, hydrodynamic interactions in polymer melts are not screened beyond the monomer length and are important in transient regimes. We show that viscoelastic hydrodynamic interactions (VHIs) lead to anomalous dynamics of a tagged chain in an unentangled melt at t View Article and Find Full Text PDF

High-density real-time PCR-based in vivo toxicogenomic screen to predict organ-specific toxicity.

Toxicogenomics, based on the temporal effects of drugs on gene expression, is able to predict toxic effects earlier than traditional technologies by analyzing changes in genomic biomarkers that could precede subsequent protein translation and initiation of histological organ damage. In the present study our objective was to extend in vivo toxicogenomic screening from analyzing one or a few tissues to multiple organs, including heart, kidney, brain, liver and spleen. Nanocapillary quantitative real-time PCR (QRT-PCR) was used in the study, due to its higher throughput, sensitivity and reproducibility, and larger dynamic range compared to DNA microarray technologies.

MicroRNA profile of polyunsaturated fatty acid treated glioma cells reveal apoptosis-specific expression changes.

Background: Polyunsaturated fatty acids (PUFAs) such as γ-linolenic acid (GLA), arachidonic acid (AA) and docosahexaenoic acid (DHA) have cytotoxic action on glioma cells.

Results: We evaluated the cytotoxic action of GLA, AA and DHA on glioma cells with specific reference to the expression of miRNAs. Relative expression of miRNAs were assessed by using high throughput nanocapillary real-time PCR.

Clinical evaluation of chlorhexidine for the control of dental biofilm in children with special needs.

Objective: The aim of the present study was to assess two vehicles and forms of the in-home administration of chlorhexidine for the control of dental biofilm in children with special needs.

Basic Research Design: Twenty-nine children aged seven to 12 years (mixed dentition phase) participated in the study. A double-blind, placebo-controlled, cross-over clinical trial was carried out with the following treatment groups: 1 - 0.

A novel study design for antibiotic trials in acute exacerbations of COPD: MAESTRAL methodology.

Antibiotics, along with oral corticosteroids, are standard treatments for acute exacerbations of chronic obstructive pulmonary disease (AECOPD). The ultimate aims of treatment are to minimize the impact of the current exacerbation, and by ensuring complete resolution, reduce the risk of relapse. In the absence of superiority studies of antibiotics in AECOPD, evidence of the relative efficacy of different drugs is lacking, and so it is difficult for physicians to select the most effective antibiotic.

Physical-chemical characteristics of whitening toothpaste and evaluation of its effects on enamel roughness.

This in vitro study evaluated the physical-chemical characteristics of whitening toothpastes and their effect on bovine enamel after application of a bleaching agent (16% carbamide peroxide). Physical-chemical analysis was made considering mass loss by desiccation, ash content and pH of the toothpastes. Thirty bovine dental enamel fragments were prepared for roughness measurements.

Phytochemical screening, antioxidant, and antimicrobial activities of the crude leaves' extract from Ipomoea batatas (L.) Lam.

Background: Ipomoea batatas (L.) Lam., popularly known as sweet potato (SP), has played an important role as an energy and a phytochemical source in human nutrition and animal feeding.

Scale-free center-of-mass displacement correlations in polymer melts without topological constraints and momentum conservation: a bond-fluctuation model study.

By Monte Carlo simulations of a variant of the bond-fluctuation model without topological constraints, we examine the center-of-mass (COM) dynamics of polymer melts in d = 3 dimensions. Our analysis focuses on the COM displacement correlation function C(N)(t)≈∂(t) (2)h(N)(t)/2, measuring the curvature of the COM mean-square displacement h(N)(t). We demonstrate that C(N)(t) ≈ -(R(N)∕T(N))(2)(ρ∗/ρ) f(x = t/T(N)) with N being the chain length (16 ≤ N ≤ 8192), R(N) ∼ N(1/2) is the typical chain size, T(N) ∼ N(2) is the longest chain relaxation time, ρ is the monomer density, ρ(*)≈N/R(N) (d) is the self-density, and f(x) is a universal function decaying asymptotically as f(x) ∼ x(-ω) with ω = (d + 2) × α, where α = 1/4 for x ≪ 1 and α = 1/2 for x ≫ 1.

Usefulness and limits of near infrared spectroscopy monitoring during endovascular neuroradiologic procedures.

Background: Transcranial cerebral oximetry (TCCO) with near-infrared spectroscopy (NIRS) is a non-invasive, bedside technique, which allows the continuous measurement of regional cerebral oxygenation. The aim of this study was to evaluate TCCO monitoring during endovascular neuroradiologic procedures.

Methods: Adult patients undergoing elective endovascular embolization of cerebral aneurysms, arteriovenous malformations, dural arteriovenous fistulas and meningiomas under general anesthesia were included in the study, over a period of 12 months.

Cluster-driven dynamical arrest in concentrated lysozyme solutions.

We present a detailed experimental and numerical study of the structural and dynamical properties of salt-free lysozyme solutions. In particular, by combining small-angle X-ray scattering (SAXS) data with neutron spin echo (NSE) and rheology experiments, we are able to identify that an arrest transition takes place at intermediate densities, driven by the slowing down of the cluster motion. Using an effective pair potential among proteins, based on the combination of short-range attraction and long-range repulsion, we account remarkably well for the peculiar volume fraction dependence of the effective structure factor measured by SAXS.

Slow and static spin correlations in Dy(2 + x)Ti(2 - x)O(7 - δ).

The static and dynamic spin correlations in the spin ices Dy(2.3)Ti(1.7)O(6.