Epitaxial Growth of Pentacene on Alkali Halide Surfaces Studied by Kelvin Probe Force Microscopy

In the field of molecular electronics thin films of molecules adsorbed on insulating surfaces are used as the functional building blocks of electronic devices. A control of the structural and electronic properties of the thin films is required for a reliable operating mode of such devices. Here, noncontact atomic force and Kelvin probe force microscopies have been used to investigate the growth and electronic properties of pentacene on KBr(001) and KCl(001) surfaces. Mainly molecular islands of upright standing pentacene are formed, whereas a new phase of tilted molecules appear near step edges on some KBr samples. Local contact potential differences (LCPD) have been studied with both Kelvin experiments and density-functional theory calculations. Large LCPD are found between the substrate and the differently oriented molecules, which may be explained by a partial charge transfer from the pentacene to the surface. The monitoring of the changes of the pentacene islands during dewetting shows that multilayers build up at the expense of monolayers. Moreover, in the Kelvin images, previously unknown line defects appear, which unveil the epitaxial growth of pentacene crystals.Comment: This document is the unedited author's version of a Submitted Work that was subsequently accepted for publication in ACSNano, copyright American Chemical Society after peer review. To access the final edited and published work see doi belo

Type I Interferon Imposes a TSG101/ISG15 Checkpoint at the Golgi for Glycoprotein Trafficking during Influenza Virus Infection

SummarySeveral enveloped viruses exploit host pathways, such as the cellular endosomal sorting complex required for transport (ESCRT) machinery, for their assembly and release. The influenza A virus (IAV) matrix protein binds to the ESCRT-I complex, although the involvement of early ESCRT proteins such as Tsg101 in IAV trafficking remain to be established. We find that Tsg101 can facilitate IAV trafficking, but this is effectively restricted by the interferon (IFN)-stimulated protein ISG15. Cytosol from type I IFN-treated cells abolished IAV hemagglutinin (HA) transport to the cell surface in infected semi-intact cells. This inhibition required Tsg101 and could be relieved with deISGylases. Tsg101 is itself ISGylated in IFN-treated cells. Upon infection, intact Tsg101-deficient cells obtained by CRISPR-Cas9 genome editing were defective in the surface display of HA and for infectious virion release. These data support the IFN-induced generation of a Tsg101- and ISG15-dependent checkpoint in the secretory pathway that compromises influenza virus release

First Results from the TOTEM Experiment

The first physics results from the TOTEM experiment are here reported, concerning the measurements of the total, differential elastic, elastic and inelastic pp cross-section at the LHC energy of $\sqrt{s}$ = 7 TeV, obtained using the luminosity measurement from CMS. A preliminary measurement of the forward charged particle $\eta$ distribution is also shown.Comment: Conference Proceeding. MPI@LHC 2010: 2nd International Workshop on Multiple Partonic Interactions at the LHC. Glasgow (UK), 29th of November to the 3rd of December 201

Site-specific protein modification using immobilized sortase in batch and continuous-flow systems

Transpeptidation catalyzed by ​sortase A allows the preparation of proteins that are site-specifically and homogeneously modified with a wide variety of functional groups, such as fluorophores, PEG moieties, lipids, glycans, bio-orthogonal reactive groups and affinity handles. This protocol describes immobilization of ​sortase A on a solid support (Sepharose beads). Immobilization of ​sortase A simplifies downstream purification of a protein of interest after labeling of its N or C terminus. Smaller batch and larger-scale continuous-flow reactions require only a limited amount of enzyme. The immobilized enzyme can be reused for multiple cycles of protein modification reactions. The described protocol also works with a Ca²⁺-independent variant of ​sortase A with increased catalytic activity. This heptamutant variant of ​sortase A (7M) was generated by combining previously published mutations, and this immobilized enzyme can be used for the modification of calcium-senstive substrates or in instances in which low temperatures are needed. Preparation of immobilized ​sortase A takes 1–2 d. Batch reactions take 3–12 h and flow reactions proceed at 0.5 ml h⁻¹, depending on the geometry of the reactor used.United States. National Institutes of Health (RO1 AI087879

Diamond detectors for the TOTEM timing upgrade

This paper describes the design and the performance of the timing detector developed by the TOTEM Collaboration for the Roman Pots (RPs) to measure the Time-Of-Flight (TOF) of the protons produced in central diffractive interactions at the LHC. The measurement of the TOF of the protons allows the determination of the longitudinal position of the proton interaction vertex and its association with one of the vertices reconstructed by the CMS detectors. The TOF detector is based on single crystal Chemical Vapor Deposition (scCVD) diamond plates and is designed to measure the protons TOF with about 50 ps time precision. This upgrade to the TOTEM apparatus will be used in the LHC run 2 and will tag the central diffractive events up to an interaction pileup of about 1. A dedicated fast and low noise electronics for the signal amplification has been developed. The digitization of the diamond signal is performed by sampling the waveform. After introducing the physics studies that will most profit from the addition of these new detectors, we discuss in detail the optimization and the performance of the first TOF detector installed in the LHC in November 2015.Peer reviewe

Measurement of elastic pp scattering at √ s = 8 TeV in the Coulomb-nuclear interference region : determination of the rho-parameter and the total cross-section

The TOTEM experiment at the CERN LHC has measured elastic proton-proton scattering at the centre-of-mass energy root s = 8 TeV and four-momentum transfers squared, vertical bar t vertical bar, from 6 x 10(-4) to 0.2GeV(2). Near the lower end of the t-interval the differential cross-section is sensitive to the interference between the hadronic and the electromagnetic scattering amplitudes. This article presents the elastic cross-section measurement and the constraints it imposes on the functional forms of the modulus and phase of the hadronic elastic amplitude. The data exclude the traditional Simplified West and Yennie interference formula that requires a constant phase and a purely exponential modulus of the hadronic amplitude. For parametrisations of the hadronic modulus with second-or third-order polynomials in the exponent, the data are compatible with hadronic phase functions giving either central or peripheral behaviour in the impact parameter picture of elastic scattering. In both cases, the.-parameter is found to be 0.12 +/- 0.03. The results for the total hadronic cross-section are sigma(tot) = (102.9 +/- 2.3) mb and (103.0 +/- 2.3) mb for central and peripheral phase formulations, respectively. Both are consistent with previous TOTEM measurements.Peer reviewe

Dietary Supplements and Sports Performance: Herbals

This is the fourth in a series of six articles to discuss the major classes of dietary supplements (vitamins; minerals; amino acids; herbs or botanicals; metabolites, constituents/extracts, or combinations). The major focus is on efficacy of such dietary supplements to enhance exercise or sport performance

Haploinsufficiency of the E3 Ubiquitin Ligase C-Terminus of Heat Shock Cognate 70 Interacting Protein (CHIP) Produces Specific Behavioral Impairments

The multifunctional E3 ubiquitin ligase CHIP is an essential interacting partner of HSP70, which together promote the proteasomal degradation of client proteins. Acute CHIP overexpression provides neuroprotection against neurotoxic mitochondrial stress, glucocorticoids, and accumulation of toxic amyloid fragments, as well as genetic mutations in other E3 ligases, which have been shown to result in familial Parkinson's disease. These studies have created a great deal of interest in understanding CHIP activity, expression and modulation. While CHIP knockout mice have the potential to provide essential insights into the molecular control of cell fate and survival, the animals have been difficult to characterize in vivo due to severe phenotypic and behavioral dysfunction, which have thus far been poorly characterized. Therefore, in the present study we conducted a battery of neurobehavioral and physiological assays of adult CHIP heterozygotic (HET) mutant mice to provide a better understanding of the functional consequence of CHIP deficiency. We found that CHIP HET mice had normal body and brain weight, body temperature, muscle tone and breathing patterns, but do have a significant elevation in baseline heart rate. Meanwhile basic behavioral screens of sensory, motor, emotional and cognitive functions were normative. We observed no alterations in performance in the elevated plus maze, light-dark preference and tail suspension assays, or two simple cognitive tasks: novel object recognition and spontaneous alternation in a Y maze. Significant deficits were found, however, when CHIP HET mice performed wire hang, inverted screen, wire maneuver, and open field tasks. Taken together, our data indicate a clear subset of behaviors that are altered at baseline in CHIP deficient animals, which will further guide whole animal studies of the effects of CHIP dysregulation on cardiac function, brain circuitry and function, and responsiveness to environmental and cellular stress