Elastic properties and line tension of self-assembled bilayer membranes.

The elastic properties of a self-assembled bilayer membrane are studied using the self-consistent field theory, applied to a model system composed of flexible amphiphilic chains dissolved in hydrophilic polymeric solvents. Examining the free energy of bilayer membranes with different geometries allows us to calculate their bending modulus, Gaussian modulus, two fourth-order membrane moduli, and the line tension. The dependence of these parameters on the microscopic characteristics of the amphiphilic chain, characterized by the volume fraction of the hydrophilic component, is systematically studied.

Probing timescales during back side ablation of Molybdenum thin films with optical and electrical measurement techniques.

In this study we present a new measurement technique to investigate the timescales of back side ablation of conductive films, using Molybdenum as an application example from photovoltaics. With ultrashort laser pulses at fluences below 0.6 J/cm(2), we ablate the Mo film in the shape of a fully intact Mo 'disc' from a transparent substrate.

Self-consistent field approach for cross-linked copolymer materials.

A generalized self-consistent field approach for polymer networks with a fixed topology is developed. It is shown that the theory reproduces the localization of cross-links, which is characteristic for gels. The theory is then used to study the order-disorder transition in regular networks of end-linked diblock copolymers.

Generation of a highly active folding enzyme by combining a parvulin-type prolyl isomerase from SurA with an unrelated chaperone domain.

Parvulins are small prolyl isomerases and serve as catalytic domains of folding enzymes. SurA (survival protein A) from the periplasm of Escherichia coli consists of an inactive (Par1) and an active (Par2) parvulin domain as well as a chaperone domain. In the absence of the chaperone domain, the folding activity of Par2 is virtually abolished.

Dynamic and dielectric response of charged colloids in electrolyte solutions to external electric fields.

Computer simulations are used to investigate the response of a charged colloid and its surrounding microion cloud to an external electric field. Both static fields and alternating fields are considered. A mesoscopic simulation method is implemented to account in full for hydrodynamic and electrostatic interactions.

Comparison of an automated respiratory systolic variation test with dynamic preload indicators to predict fluid responsiveness after major surgery.

Background: Predicting the response of cardiac output to volume administration remains an ongoing clinical challenge. The objective of our study was to compare the ability to predict volume responsiveness of various functional measures of cardiac preload. These included pulse pressure variation (PPV), stroke volume variation (SVV), and the recently launched automated respiratory systolic variation test (RSVT) in patients after major surgery.

Introducing a new breed of wine yeast: interspecific hybridisation between a commercial Saccharomyces cerevisiae wine yeast and Saccharomyces mikatae.

Interspecific hybrids are commonplace in agriculture and horticulture; bread wheat and grapefruit are but two examples. The benefits derived from interspecific hybridisation include the potential of generating advantageous transgressive phenotypes. This paper describes the generation of a new breed of wine yeast by interspecific hybridisation between a commercial Saccharomyces cerevisiae wine yeast strain and Saccharomyces mikatae, a species hitherto not associated with industrial fermentation environs.

Mature T-cell lymphomagenesis induced by retroviral insertional activation of Janus kinase 1.

Retroviral vectors (RVs) are powerful tools in clinical gene therapy. However, stable genomic integration of RVs can be oncogenic, as reported in several animal models and in clinical trials. Previously, we observed that T-cell receptor (TCR) polyclonal mature T cells are resistant to transformation after gammaretroviral transfer of (proto-)oncogenes, whereas TCR-oligoclonal T cells were transformable in the same setting.

Molecular function of the prolyl cis/trans isomerase and metallochaperone SlyD.

SlyD is a bacterial two-domain protein that functions as a molecular chaperone, a prolyl cis/trans isomerase, and a nickel-binding protein. This review summarizes recent findings about the molecular enzyme mechanism of SlyD. The chaperone function located in one domain of SlyD is involved in twin-arginine translocation and increases the catalytic efficiency of the prolyl cis/trans isomerase domain in protein folding by two orders of magnitude.

AC-field-induced polarization for uncharged colloids in salt solution: a dissipative particle dynamics simulation.

We study the response of a spherical colloid under alternating electric fields (AC fields) by mesoscopic simulation method, accounting in full for hydrodynamic and electrostatic interactions. We focus on a special case of uncharged colloids. The main polarization mechanism is the "volume polarization", where ionic currents are deflected by the core of the uncharged colloid.

Monolayer curvature stabilizes nanoscale raft domains in mixed lipid bilayers.

According to the lipid raft hypothesis, biological lipid membranes are laterally heterogeneous and filled with nanoscale ordered "raft" domains, which are believed to play an important role for the organization of proteins in membranes. However, the mechanisms stabilizing such small rafts are not clear, and even their existence is sometimes questioned. Here, we report the observation of raft-like structures in a coarse-grained molecular model for multicomponent lipid bilayers.

Initiation of phage infection by partial unfolding and prolyl isomerization.

Infection of Escherichia coli by the filamentous phage fd starts with the binding of the N2 domain of the phage gene-3-protein to an F pilus. This interaction triggers partial unfolding of the gene-3-protein, cis → trans isomerization at Pro-213, and domain disassembly, thereby exposing its binding site for the ultimate receptor TolA. The trans-proline sets a molecular timer to maintain the binding-active state long enough for the phage to interact with TolA.

The prolyl isomerase SlyD is a highly efficient enzyme but decelerates the conformational folding of a client protein.

Folding enzymes often use distinct domains for the interaction with a folding protein chain and for the catalysis of intrinsically slow reactions such as prolyl cis/trans isomerization. Here, we investigated the refolding reaction of ribonuclease T1 in the presence of the prolyl isomerase SlyD from Escherichia coli to examine how this enzyme catalyzes the folding of molecules with an incorrect trans proline isomer and how it modulates the conformational folding of the molecules with the correct cis proline. The kinetic analysis suggests that prolyl cis → trans isomerization in the SlyD-bound state shows a rate near 100 s(-1) and is thus more than 10(4)-fold accelerated, relative to the uncatalyzed reaction.

Unique proline-rich domain regulates the chaperone function of AIPL1.

Human aryl hydrocarbon receptor (AHR) interacting protein (AIP) and AIP like 1 (AIPL1) are cochaperones of Hsp90 which share 49% sequence identity. Both proteins contain an N-terminal FKBP-like prolyl peptidyl isomerase (PPIase) domain followed by a tetratricopeptide repeat (TPR) domain. In addition, AIPL1 harbors a unique C-terminal proline-rich domain (PRD).

Haemodynamically irrelevant pericardial effusion is associated with increased mortality in patients with chronic heart failure.

Aims: Pericardial effusion (PE) is a common finding in cardiac patients with chronic heart failure. The prognostic relevance of a small, haemodynamically non-compromising PE in such patients, however, remains to be determined.

Methods And Results: All patients referred to our heart failure clinic and having a baseline echocardiography and follow-up clinical visits were included.

Transcapsular arterial neovascularization of liver transplants increases the risk of intraoperative bleeding during retransplantation.

Arterial neovascularization of liver grafts can be a source of significant blood loss during retransplantation. This study evaluated the effect of transcapsular arterial neovascularization on intraoperative blood loss during retransplantation and long-term follow-up. Eleven consecutive patients with transcapsular arterial neovascularization (seven male, four female; nine children, two adults; mean age 12.

Yersinia enterocolitica and Photorhabdus asymbiotica β-lactamases BlaA are exported by the twin-arginine translocation pathway.

In general, β-lactamases of medically important Gram-negative bacteria are Sec-dependently translocated into the periplasm. In contrast, β-lactamases of Mycobacteria spp. (BlaC, BlaS) and the Gram-negative environmental bacteria Stenotrophomonas maltophilia (L2) and Xanthomonas campestris (Bla(XCC-1)) have been reported to be secreted by the twin-arginine translocation (Tat) system.

Safe lifting programs at long-term care facilities and their impact on workers' compensation costs.

Objective: To determine the utility of a safe lifting program index and a measure of lift inventory to predict workers' compensation claim frequency and costs in long-term care facilities in 23 states.

Methods: Workers' compensation claims and cost data were matched to Center for Medicare and Medicaid Services (CMS)-certified facilities (N = 656). Facility safe lifting program index were derived from interviews with directors of nursing in a subset (N = 271).

Dielectric response of nanoscopic spherical colloids in alternating electric fields: a dissipative particle dynamics simulation.

We study the response of single nanosized spherical colloids in electrolyte solution to an alternating electric field (AC field) by computer simulations. We use a coarse-grained mesoscopic simulation approach that accounts in full for hydrodynamic and electrostatic interactions as well as for thermal fluctuations. The solvent is modeled as a fluid of single dissipative particle dynamics (DPD) beads, and the colloidal particle is modeled as a rigid body made of DPD beads.

A gene therapeutic approach to correct splice defects with modified U1 and U6 snRNPs.

Splicing is an essential cellular process to generate mature transcripts from pre-mRNA. It requires the splice factor U1 small nuclear ribonucleoprotein (U1), which promotes exon recognition by base-pairing interaction with the splice donor site (SD). After U1 dissociation, exon recognition is maintained by U6 small nuclear ribonucleoproteins (U6).

Separation of chiral particles in micro- or nanofluidic channels.

We propose a method to separate enantiomers in microfluidic or nanofluidic channels. It requires flow profiles that break chiral symmetry and have regions with high local shear. Such profiles can be generated in channels confined by walls with different hydrodynamic boundary conditions (e.

Anti-metastatic treatment in colorectal cancer: targeting signaling pathways.

Colorectal cancer is one of the most common cancers worldwide and one of the leading causes of cancer-related death in the Western world. Tumor progression towards metastasis affects a large number of patients with colorectal cancer and seriously affects their clinical outcome. Therefore, considerable effort has been made towards the development of therapeutic strategies that can decrease or prevent colorectal cancer metastasis.

Free and total plasma levels of lopinavir during pregnancy, at delivery and postpartum: implications for dosage adjustments in pregnant women.

Background: Physiological changes associated with pregnancy may alter antiretroviral plasma concentrations and might jeopardize prevention of mother-to-child HIV transmission. Lopinavir is one of the protease inhibitors more frequently prescribed during pregnancy in Europe. We described the free and total pharmacokinetics of lopinavir in HIV-infected pregnant and non-pregnant women, and evaluated whether significant alterations in its disposition and protein binding warrant systematic dosage adjustment.

Nicotinic acid adenine dinucleotide phosphate (NAADP) degradation by alkaline phosphatase.

Nicotinic acid adenine dinucleotide phosphate (NAADP) is a ubiquitous second messenger providing a Ca(2+) trigger in a wide range of cell types. However, its metabolism is not well understood. Here, we demonstrate the presence of endogenous NAADP in HeLa cells.