Central Executive Dysfunction and Deferred Prefrontal Processing in Veterans with Gulf War Illness.

Gulf War Illness is associated with toxic exposure to cholinergic disruptive chemicals. The cholinergic system has been shown to mediate the central executive of working memory (WM). The current work proposes that impairment of the cholinergic system in Gulf War Illness patients (GWIPs) leads to behavioral and neural deficits of the central executive of WM. A large sample of GWIPs and matched controls (MCs) underwent functional magnetic resonance imaging during a varied-load working memory task. Compared to MCs, GWIPs showed a greater decline in performance as WM-demand increased. Functional imaging suggested that GWIPs evinced separate processing strategies, deferring prefrontal cortex activity from encoding to retrieval for high demand conditions. Greater activity during high-demand encoding predicted greater WM performance. Behavioral data suggest that WM executive strategies are impaired in GWIPs. Functional data further support this hypothesis and suggest that GWIPs utilize less effective strategies during high-demand WM

Nyquist method for Wigner-Poisson quantum plasmas

By means of the Nyquist method, we investigate the linear stability of electrostatic waves in homogeneous equilibria of quantum plasmas described by the Wigner-Poisson system. We show that, unlike the classical Vlasov-Poisson system, the Wigner-Poisson case does not necessarily possess a Penrose functional determining its linear stability properties. The Nyquist method is then applied to a two-stream distribution, for which we obtain an exact, necessary and sufficient condition for linear stability, as well as to a bump-in-tail equilibrium.Comment: 6 figure

Opioids and viral infections: A double-edged sword

Opioids and their receptors have received remarkable attention because they have the ability to alter immune function, which affects disease progression. In vitro and in vivo findings as well as observations in humans indicate that opioids and their receptors positively or negatively affect viral replication and virus-mediated pathology. The present study reviews recent insights in the role of opioids and their receptors in viral infections and discusses possible therapeutic opportunities. This review supports the emerging concept that opioids and their receptors have both favorable and unfavorable effects on viral disease, depending on the type of virus. Targeting of the opioid system is a potential option for developing effective therapies; however caution is required in relation to the beneficial functions of opioid systems. © 2016 Tahamtan, Tavakoli-Yaraki, Mokhtari-Azad, Teymoori-Rad, Bont, Shokri and Salimi

Controlling the drying-induced peeling of colloidal films

In this work, we investigated the effect of the suspension properties on the drying dynamics and the resulting film peeling instability. To do so, a comprehensive series of experiments were conducted using drops of aqueous mixtures of colloidal silica dispersions and polyethylene oxide (PEO) additives. Time- lapse digital microscope images of the evaporating droplets show that film peeling can be discouraged and eventually eliminated with an increase in PEO concentration and molecular weight. This is due to the additives modifying the suspension properties which in turn modify the drying front length across the evaporating surface. Our result extends the understanding of the physics of film failure which is relevant information for various industrial processes such as in inkjet printing and coating applications

Atomic and electronic structure of bismuth-bilayer-terminated Bi2Se3(0001) prepared by atomic hydrogen etching

Under the terms of the Creative Commons Attribution License 3.0 (CC-BY).A bilayer of bismuth is recognized as a prototype two-dimensional topological insulator. Here we present a simple and well reproducible top-down approach to prepare a flat and well ordered bismuth bilayer with a lateral size of several hundred nanometers on Bi2Se3(0001). Using scanning tunneling microscopy, surface x-ray diffraction, and Auger electron spectroscopy we show that exposure of Bi2Se3(0001) to atomic hydrogen completely removes selenium from the top quintuple layer. The band structure of the system, calculated from first principles for the experimentally derived atomic structure, is in excellent agreement with recent photoemission data. Our results open interesting perspectives for the study of topological insulators in general.This work is supported by the Deutsche Forschungsgemeinschaft through priority program SPP 1666 (Topological Insulators). M.M.O. and E.V.C. thank the Tomsk State University Academic D.I. Mendeleev Fund Program (Research Grant No. 8.1.05.2015).Peer Reviewe

Atomic and electronic structure of bismuth-bilayer-terminated Bi2Se3(0001) prepared by atomic hydrogen etching

A bilayer of bismuth is recognized as a prototype two-dimensional topological insulator. Here we present a simple and well reproducible top-down approach to prepare a flat and well ordered bismuth bilayer with a lateral size of several hundred nanometers on Bi2Se3(0001). Using scanning tunneling microscopy, surface x-ray diffraction, and Auger electron spectroscopy we show that exposure of Bi2Se3(0001) to atomic hydrogen completely removes selenium from the top quintuple layer. The band structure of the system, calculated from first principles for the experimentally derived atomic structure, is in excellent agreement with recent photoemission data. Our results open interesting perspectives for the study of topological insulators in general

Survey of variation in human transcription factors reveals prevalent DNA binding changes

Published in final edited form as: Science. 2016 Mar 25; 351(6280): 1450–1454. Published online 2016 Mar 24. doi: 10.1126/science.aad2257Sequencing of exomes and genomes has revealed abundant genetic variation affecting the coding sequences of human transcription factors (TFs), but the consequences of such variation remain largely unexplored. We developed a computational, structure-based approach to evaluate TF variants for their impact on DNA binding activity and used universal protein-binding microarrays to assay sequence-specific DNA binding activity across 41 reference and 117 variant alleles found in individuals of diverse ancestries and families with Mendelian diseases. We found 77 variants in 28 genes that affect DNA binding affinity or specificity and identified thousands of rare alleles likely to alter the DNA binding activity of human sequence-specific TFs. Our results suggest that most individuals have unique repertoires of TF DNA binding activities, which may contribute to phenotypic variation.National Institutes of Health; NHGRI R01 HG003985; P50 HG004233; A*STAR National Science Scholarship; National Science Foundatio

Can concurrent lower gastrointestinal manifestations help the timely diagnosis of small intestinal bacterial overgrowth in CVID patients?

Summary Introduction and objective. Gastrointestinal complications are considered as one of the most common manifestations in patients with Common Variable Immunodeficiency (CVID). These complications can result from Small Intestinal Bacterial Overgrowth (SIBO). Hydrogen breath test is extensively used to diagnose SIBO. The objective of this study was to evaluate the prevalence of SIBO using the Hydrogen Breath Test (HBT) in patients with CVID. Materials and methods. Twenty-seven patients with CVID entered this cross-sectional study. Demographic and lower gastrointestinal symptoms were recorded in a check list. Hemoglobin level was measured in all patients. The concentration of IgA and IgG was assessed using nephelometry. Moreover, SIBO was detected by means of Glucose hydrogen breath test. Results. The mean (± SD) age of the patients was 35.25 (± 11.69) years. Twenty patients (74.1) manifested at least one lower gastrointestinal symptom. The most frequent lower gastrointestinal manifestations were bloating (66.7) and chronic diarrhea (40.7), respectively. IgA level less than 10 mg/dl and IgG level less than 600 mg/dl were determined in 77.8 and 25.9 of patients, respectively. Positive HBT was detected in 40.7 (n = 11) of the patients. In the positive HBT group, bloating, chronic diarrhea and abdominal pain were the most common lower GI manifestations. There was no significant difference in terms of age, BMI, IgA level, and duration of CVID between the positive and negative HBT groups. The significant association of co-occurrence of anemia and abdominal pain with positive HBT (positive predictive value: 100) might be considered as a clue to SIBO diagnosis. Conclusions. Regarding the high prevalence and non-specific manifestation of SIBO, it is suggested to consider concurrent symptoms in patients with CVID to manage the timely and precise diagnosis of SIBO. © 2021 Associazione Allergologi Immunologi Italiani Territoriali e Ospedalieri-AAIITO. Published by EDRA SpA. All rights reserved

Kinetics and thermodynamics of salt-dependent T7 gene 2.5 protein binding to single- and double-stranded DNA

Bacteriophage T7 gene 2.5 protein (gp2.5) is a single-stranded DNA (ssDNA)-binding protein that has essential roles in DNA replication, recombination and repair. However, it differs from other ssDNA-binding proteins by its weaker binding to ssDNA and lack of cooperative ssDNA binding. By studying the rate-dependent DNA melting force in the presence of gp2.5 and its deletion mutant lacking 26 C-terminal residues, we probe the kinetics and thermodynamics of gp2.5 binding to ssDNA and double-stranded DNA (dsDNA). These force measurements allow us to determine the binding rate of both proteins to ssDNA, as well as their equilibrium association constants to dsDNA. The salt dependence of dsDNA binding parallels that of ssDNA binding. We attribute the four orders of magnitude salt-independent differences between ssDNA and dsDNA binding to nonelectrostatic interactions involved only in ssDNA binding, in contrast to T4 gene 32 protein, which achieves preferential ssDNA binding primarily through cooperative interactions. The results support a model in which dimerization interactions must be broken for DNA binding, and gp2.5 monomers search dsDNA by 1D diffusion to bind ssDNA. We also quantitatively compare the salt-dependent ssDNA- and dsDNA-binding properties of the T4 and T7 ssDNA-binding proteins for the first time