Comparison of Saccharomyces cerevisiae F-BAR Domain Structures Reveals a Conserved Inositol Phosphate Binding Site

DOE PAGES

Moravcevic, Katarina; Alvarado, Diego; Schmitz, Karl R.; ...

2015-01-22

F-BAR domains control membrane interactions in endocytosis, cytokinesis, and cell signaling. Although they are generally thought to bind curved membranes containing negatively charged phospholipids, numerous functional studies argue that differences in lipid-binding selectivities of F-BAR domains are functionally important. Here in this paper, we compare membrane-binding properties of the Saccharomyces cerevisiae F-BAR domains in vitro and in vivo. Whereas some F-BAR domains (such as Bzz1p and Hof1p F-BARs) bind equally well to all phospholipids, the F-BAR domain from the RhoGAP Rgd1p preferentially binds phosphoinositides. We determined X-ray crystal structures of F-BAR domains from Hof1p and Rgd1p, the latter bound tomore » an inositol phosphate. The structures explain phospholipid-binding selectivity differences and reveal an F-BAR phosphoinositide binding site that is fully conserved in a mammalian RhoGAP called Gmip and is partly retained in certain other F-BAR domains. In conclusion, our findings reveal previously unappreciated determinants of F-BAR domain lipid-binding specificity and provide a basis for its prediction from sequence.« less

Closed membrane shapes with attached BAR domains subject to external force of actin filaments.

PubMed

Mesarec, Luka; Góźdź, Wojciech; Iglič, Veronika Kralj; Kralj, Samo; Iglič, Aleš

2016-05-01

Membrane deformations induced by attached BAR superfamily domains could trigger or facilitate the growth of plasma membrane protrusions. The BAR domain family consists of BAR, F-BAR and I-BAR domains, each enforcing a different local curvature when attached to the membrane surface. Our theoretical study mainly focuses on the role of I-BAR in the membrane tubular deformations generated or stabilised by actin filaments. The influence of the area density of membrane attached BAR domains and their intrinsic curvature on the closed membrane shapes (vesicles) was investigated numerically. We derived an analytical approximative expression for the critical relative area density of BARs at which the membrane tubular protrusions on vesicles are most prominent. We have shown that the BARs with a higher intrinsic curvature induce thinner and longer cylindrical protrusions. The average orientation of the membrane attached BARs is altered when the vesicle shape is subjected to external force of growing actin rod-like structure inside a vesicle. The average orientation angle of membrane attached BARs may indicate whether the actin filaments are just stabilising the protrusion or generating it by stretching the vesicle. Copyright © 2016 Elsevier B.V. All rights reserved.

An Amphipathic Helix Directs Cellular Membrane Curvature Sensing and Function of the BAR Domain Protein PICK1.

PubMed

Herlo, Rasmus; Lund, Viktor K; Lycas, Matthew D; Jansen, Anna M; Khelashvili, George; Andersen, Rita C; Bhatia, Vikram; Pedersen, Thomas S; Albornoz, Pedro B C; Johner, Niklaus; Ammendrup-Johnsen, Ina; Christensen, Nikolaj R; Erlendsson, Simon; Stoklund, Mikkel; Larsen, Jannik B; Weinstein, Harel; Kjærulff, Ole; Stamou, Dimitrios; Gether, Ulrik; Madsen, Kenneth L

2018-05-15

BAR domains are dimeric protein modules that sense, induce, and stabilize lipid membrane curvature. Here, we show that membrane curvature sensing (MCS) directs cellular localization and function of the BAR domain protein PICK1. In PICK1, and the homologous proteins ICA69 and arfaptin2, we identify an amphipathic helix N-terminal to the BAR domain that mediates MCS. Mutational disruption of the helix in PICK1 impaired MCS without affecting membrane binding per se. In insulin-producing INS-1E cells, super-resolution microscopy revealed that disruption of the helix selectively compromised PICK1 density on insulin granules of high curvature during their maturation. This was accompanied by reduced hormone storage in the INS-1E cells. In Drosophila, disruption of the helix compromised growth regulation. By demonstrating size-dependent binding on insulin granules, our finding highlights the function of MCS for BAR domain proteins in a biological context distinct from their function, e.g., at the plasma membrane during endocytosis. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

Coordinated autoinhibition of F-BAR domain membrane binding and WASp activation by Nervous Wreck.

PubMed

Stanishneva-Konovalova, Tatiana B; Kelley, Charlotte F; Eskin, Tania L; Messelaar, Emily M; Wasserman, Steven A; Sokolova, Olga S; Rodal, Avital A

2016-09-20

Membrane remodeling by Fes/Cip4 homology-Bin/Amphiphysin/Rvs167 (F-BAR) proteins is regulated by autoinhibitory interactions between their SRC homology 3 (SH3) and F-BAR domains. The structural basis of autoregulation, and whether it affects interactions of SH3 domains with other cellular ligands, remain unclear. Here we used single-particle electron microscopy to determine the structure of the F-BAR protein Nervous Wreck (Nwk) in both soluble and membrane-bound states. On membrane binding, Nwk SH3 domains do not completely dissociate from the F-BAR dimer, but instead shift from its concave surface to positions on either side of the dimer. Unexpectedly, along with controlling membrane binding, these autoregulatory interactions inhibit the ability of Nwk-SH3a to activate Wiskott-Aldrich syndrome protein (WASp)/actin related protein (Arp) 2/3-dependent actin filament assembly. In Drosophila neurons, Nwk autoregulation restricts SH3a domain-dependent synaptopod formation, synaptic growth, and actin organization. Our results define structural rearrangements in Nwk that control F-BAR-membrane interactions as well as SH3 domain activities, and suggest that these two functions are tightly coordinated in vitro and in vivo.

Yeast Ivy1p Is a Putative I-BAR-domain Protein with pH-sensitive Filament Forming Ability in vitro.

PubMed

Itoh, Yuzuru; Kida, Kazuki; Hanawa-Suetsugu, Kyoko; Suetsugu, Shiro

2016-01-01

Bin-Amphiphysin-Rvs161/167 (BAR) domains mold lipid bilayer membranes into tubules, by forming a spiral polymer on the membrane. Most BAR domains are thought to be involved in forming membrane invaginations through their concave membrane binding surfaces, whereas some members have convex membrane binding surfaces, and thereby mold membranes into protrusions. The BAR domains with a convex surface form a subtype called the inverse BAR (I-BAR) domain or IRSp53-MIM-homology domain (IMD). Although the mammalian I-BAR domains have been studied, those from other organisms remain elusive. Here, we found putative I-BAR domains in Fungi and animal-like unicellular organisms. The fungal protein containing the putative I-BAR-domain is known as Ivy1p in yeast, and is reportedly localized in the vacuole. The phylogenetic analysis of the I-BAR domains revealed that the fungal I-BAR-domain containing proteins comprise a distinct group from those containing IRSp53 or MIM. Importantly, Ivy1p formed a polymer with a diameter of approximately 20 nm in vitro, without a lipid membrane. The filaments were formed at neutral pH, but disassembled when pH was reverted to basic. Moreover, Ivy1p and the I-BAR domain expressed in mammalian HeLa cells was localized at a vacuole-like structure as filaments as revealed by super-resolved microscopy. These data indicate the pH-sensitive polymer forming ability and the functional conservation of Ivy1p in eukaryotic cells.

Performance simulation of BaBar DIRC bar boxes in TORCH

NASA Astrophysics Data System (ADS)

Föhl, K.; Brook, N.; Castillo García, L.; Cussans, D.; Forty, R.; Frei, C.; Gao, R.; Gys, T.; Harnew, N.; Piedigrossi, D.; Rademacker, J.; Ros García, A.; van Dijk, M.

2017-12-01

TORCH is a large-area precision time-of-flight detector based on the DIRC principle. The DIRC bar boxes of the BaBar experiment at SLAC could possibly be reused to form a part of the TORCH detector time-of-flight wall area, proposed to provide positive particle identification of low momentum kaons in the LHCb experiment at CERN. For a potential integration of BaBar bar boxes into TORCH, new imaging readout optics are required. From the several designs of readout optics that have been considered, two are used in this paper to study the effect of BaBar bar optical imperfections on the detector reconstruction performance. The kaon-pion separation powers obtained from analysing simulated photon hit patterns show the performance reduction for a BaBar bar of non-square geometry compared to a perfectly rectangular cross section.

Salt Bridge Formation between the I-BAR Domain and Lipids Increases Lipid Density and Membrane Curvature.

PubMed

Takemura, Kazuhiro; Hanawa-Suetsugu, Kyoko; Suetsugu, Shiro; Kitao, Akio

2017-07-28

The BAR domain superfamily proteins sense or induce curvature in membranes. The inverse-BAR domain (I-BAR) is a BAR domain that forms a straight "zeppelin-shaped" dimer. The mechanisms by which IRSp53 I-BAR binds to and deforms a lipid membrane are investigated here by all-atom molecular dynamics simulation (MD), binding energy analysis, and the effects of mutation experiments on filopodia on HeLa cells. I-BAR adopts a curved structure when crystallized, but adopts a flatter shape in MD. The binding of I-BAR to membrane was stabilized by ~30 salt bridges, consistent with experiments showing that point mutations of the interface residues have little effect on the binding affinity whereas multiple mutations have considerable effect. Salt bridge formation increases the local density of lipids and deforms the membrane into a concave shape. In addition, the point mutations that break key intra-molecular salt bridges within I-BAR reduce the binding affinity; this was confirmed by expressing these mutants in HeLa cells and observing their effects. The results indicate that the stiffness of I-BAR is important for membrane deformation, although I-BAR does not act as a completely rigid template.

Correlative Microscopy of Vitreous Sections Provides Insights into BAR-Domain Organization In Situ.

PubMed

Bharat, Tanmay A M; Hoffmann, Patrick C; Kukulski, Wanda

2018-04-10

Electron microscopy imaging of macromolecular complexes in their native cellular context is limited by the inherent difficulty to acquire high-resolution tomographic data from thick cells and to specifically identify elusive structures within crowded cellular environments. Here, we combined cryo-fluorescence microscopy with electron cryo-tomography of vitreous sections into a coherent correlative microscopy workflow, ideal for detection and structural analysis of elusive protein assemblies in situ. We used this workflow to address an open question on BAR-domain coating of yeast plasma membrane compartments known as eisosomes. BAR domains can sense or induce membrane curvature, and form scaffold-like membrane coats in vitro. Our results demonstrate that in cells, the BAR protein Pil1 localizes to eisosomes of varying membrane curvature. Sub-tomogram analysis revealed a dense protein coat on curved eisosomes, which was not present on shallow eisosomes, indicating that while BAR domains can assemble at shallow membranes in vivo, scaffold formation is tightly coupled to curvature generation. Copyright © 2018 MRC Laboratory of Molecular Biology. Published by Elsevier Ltd.. All rights reserved.

Membrane re-modelling by BAR domain superfamily proteins via molecular and non-molecular factors.

PubMed

Nishimura, Tamako; Morone, Nobuhiro; Suetsugu, Shiro

2018-04-17

Lipid membranes are structural components of cell surfaces and intracellular organelles. Alterations in lipid membrane shape are accompanied by numerous cellular functions, including endocytosis, intracellular transport, and cell migration. Proteins containing Bin-Amphiphysin-Rvs (BAR) domains (BAR proteins) are unique, because their structures correspond to the membrane curvature, that is, the shape of the lipid membrane. BAR proteins present at high concentration determine the shape of the membrane, because BAR domain oligomers function as scaffolds that mould the membrane. BAR proteins co-operate with various molecular and non-molecular factors. The molecular factors include cytoskeletal proteins such as the regulators of actin filaments and the membrane scission protein dynamin. Lipid composition, including saturated or unsaturated fatty acid tails of phospholipids, also affects the ability of BAR proteins to mould the membrane. Non-molecular factors include the external physical forces applied to the membrane, such as tension and friction. In this mini-review, we will discuss how the BAR proteins orchestrate membrane dynamics together with various molecular and non-molecular factors. © 2018 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

The F-BAR domains from srGAP1, srGAP2 and srGAP3 regulate membrane deformation differently

PubMed Central

Coutinho-Budd, Jaeda; Ghukasyan, Vladimir; Zylka, Mark J.; Polleux, Franck

2012-01-01

Summary Coordination of membrane deformation and cytoskeletal dynamics lies at the heart of many biological processes critical for cell polarity, motility and morphogenesis. We have recently shown that Slit-Robo GTPase-activating protein 2 (srGAP2) regulates neuronal morphogenesis through the ability of its F-BAR domain to regulate membrane deformation and induce filopodia formation. Here, we demonstrate that the F-BAR domains of two closely related family members, srGAP1 and srGAP3 [designated F-BAR(1) and F-BAR(3), respectively] display significantly different membrane deformation properties in non-neuronal COS7 cells and in cortical neurons. F-BAR(3) induces filopodia in both cell types, though less potently than F-BAR(2), whereas F-BAR(1) prevents filopodia formation in cortical neurons and reduces plasma membrane dynamics. These three F-BAR domains can heterodimerize, and they act synergistically towards filopodia induction in COS7 cells. As measured by fluorescence recovery after photobleaching, F-BAR(2) displays faster molecular dynamics than F-BAR(3) and F-BAR(1) at the plasma membrane, which correlates well with its increased potency to induce filopodia. We also show that the molecular dynamic properties of F-BAR(2) at the membrane are partially dependent on F-Actin. Interestingly, acute phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] depletion in cells does not interfere with plasma membrane localization of F-BAR(2), which is compatible with our result showing that F-BAR(2) binds to a broad range of negatively-charged phospholipids present at the plasma membrane, including phosphatidylserine (PtdSer). Overall, our results provide novel insights into the functional diversity of the membrane deformation properties of this subclass of F-BAR-domains required for cell morphogenesis. PMID:22467852

A Coincidence Detection Mechanism Controls PX-BAR Domain-Mediated Endocytic Membrane Remodeling via an Allosteric Structural Switch.

PubMed

Lo, Wen-Ting; Vujičić Žagar, Andreja; Gerth, Fabian; Lehmann, Martin; Puchkov, Dymtro; Krylova, Oxana; Freund, Christian; Scapozza, Leonardo; Vadas, Oscar; Haucke, Volker

2017-11-20

Clathrin-mediated endocytosis occurs by bending and remodeling of the membrane underneath the coat. Bin-amphiphysin-rvs (BAR) domain proteins are crucial for endocytic membrane remodeling, but how their activity is spatiotemporally controlled is largely unknown. We demonstrate that the membrane remodeling activity of sorting nexin 9 (SNX9), a late-acting endocytic PX-BAR domain protein required for constriction of U-shaped endocytic intermediates, is controlled by an allosteric structural switch involving coincident detection of the clathrin adaptor AP2 and phosphatidylinositol-3,4-bisphosphate (PI(3,4)P 2 ) at endocytic sites. Structural, biochemical, and cell biological data show that SNX9 is autoinhibited in solution. Binding to PI(3,4)P 2 via its PX-BAR domain, and concomitant association with AP2 via sequences in the linker region, releases SNX9 autoinhibitory contacts to enable membrane constriction. Our results reveal a mechanism for restricting the latent membrane remodeling activity of BAR domain proteins to allow spatiotemporal coupling of membrane constriction to the progression of the endocytic pathway. Copyright © 2017 Elsevier Inc. All rights reserved.

Through its F-BAR and RhoGAP domains, Rgd1p acts in different polarized growth processes in budding yeast

PubMed Central

Lefebvre, Fabien; Prouzet-Mauléon, Valérie; Vieillemard, Aurélie; Thoraval, Didier; Crouzet, Marc

2009-01-01

Protein domain architecture can be used to construct supramolecular structures, to carry out specific functions and to mediate signaling in prokaryotic and eukaryotic cells. The Rgd1p protein of budding yeast contains two domains with different functions in the cell: the F-BAR and RhoGAP domains. The F-BAR domain has been shown to interact with membrane phospholipids and is thought to induce or sense membrane curvature. The RhoGAP domain activates the GTP hydrolysis of two Rho GTPases, thereby regulating different cellular pathways. Specific molecular interactions with the F-BAR and RhoGAP domains, cell signaling and interplay between these domains may allow the Rgd1p protein to act in several different biological processes, all of which are required for polarized growth in yeast. PMID:19704907

P-type doping of GaN(000\\bar{1}) by magnesium ion implantation

NASA Astrophysics Data System (ADS)

Narita, Tetsuo; Kachi, Tetsu; Kataoka, Keita; Uesugi, Tsutomu

2017-01-01

Magnesium ion implantation has been performed on a GaN(000\\bar{1}) substrate, whose surface has a high thermal stability, thus allowing postimplantation annealing without the use of a protective layer. The current-voltage characteristics of p-n diodes fabricated on GaN(000\\bar{1}) showed distinct rectification at a turn-on voltage of about 3 V, although the leakage current varied widely among the diodes. Coimplantation with magnesium and hydrogen ions effectively suppressed the leakage currents and device-to-device variations. In addition, an electroluminescence band was observed at wavelengths shorter than 450 nm for these diodes. These results provide strong evidence that implanted magnesium ions create acceptors in GaN(000\\bar{1}).

FlnA binding to PACSIN2 F-BAR domain regulates membrane tubulation in megakaryocytes and platelets.

PubMed

Begonja, Antonija Jurak; Pluthero, Fred G; Suphamungmee, Worawit; Giannini, Silvia; Christensen, Hilary; Leung, Richard; Lo, Richard W; Nakamura, Fumihiko; Lehman, William; Plomann, Markus; Hoffmeister, Karin M; Kahr, Walter H A; Hartwig, John H; Falet, Hervé

2015-07-02

Bin-Amphiphysin-Rvs (BAR) and Fes-CIP4 homology BAR (F-BAR) proteins generate tubular membrane invaginations reminiscent of the megakaryocyte (MK) demarcation membrane system (DMS), which provides membranes necessary for future platelets. The F-BAR protein PACSIN2 is one of the most abundant BAR/F-BAR proteins in platelets and the only one reported to interact with the cytoskeletal and scaffold protein filamin A (FlnA), an essential regulator of platelet formation and function. The FlnA-PACSIN2 interaction was therefore investigated in MKs and platelets. PACSIN2 associated with FlnA in human platelets. The interaction required FlnA immunoglobulin-like repeat 20 and the tip of PACSIN2 F-BAR domain and enhanced PACSIN2 F-BAR domain membrane tubulation in vitro. Most human and wild-type mouse platelets had 1 to 2 distinct PACSIN2 foci associated with cell membrane GPIbα, whereas Flna-null platelets had 0 to 4 or more foci. Endogenous PACSIN2 and transfected enhanced green fluorescent protein-PACSIN2 were concentrated in midstage wild-type mouse MKs in a well-defined invagination of the plasma membrane reminiscent of the initiating DMS and dispersed in the absence of FlnA binding. The DMS appeared less well defined, and platelet territories were not readily visualized in Flna-null MKs. We conclude that the FlnA-PACSIN2 interaction regulates membrane tubulation in MKs and platelets and likely contributes to DMS formation. © 2015 by The American Society of Hematology.

Calculations of antiproton-nucleus quasi-bound states using the Paris N bar N potential

NASA Astrophysics Data System (ADS)

Hrtánková, Jaroslava; Mareš, Jiří

2018-01-01

An optical potential constructed using the p bar N scattering amplitudes derived from the 2009 version of the Paris N bar N potential is applied in calculations of p bar quasi-bound states in selected nuclei across the periodic table. A proper self-consistent procedure for treating energy dependence of the amplitudes in a nucleus appears crucial for evaluating p bar binding energies and widths. Particular attention is paid to the role of P-wave amplitudes. While the P-wave potential nearly does not affect calculated p bar binding energies, it reduces considerably the corresponding widths. The Paris S-wave potential supplemented by a phenomenological P-wave term yields in dynamical calculations p bar binding energies Bpbar ≈ 200 MeV and widths Γpbar ∼ 200- 230 MeV, which is very close to the values obtained within the RMF model consistent with p bar -atom data.

Deciphering the BAR code of membrane modulators.

PubMed

Salzer, Ulrich; Kostan, Julius; Djinović-Carugo, Kristina

2017-07-01

The BAR domain is the eponymous domain of the "BAR-domain protein superfamily", a large and diverse set of mostly multi-domain proteins that play eminent roles at the membrane cytoskeleton interface. BAR domain homodimers are the functional units that peripherally associate with lipid membranes and are involved in membrane sculpting activities. Differences in their intrinsic curvatures and lipid-binding properties account for a large variety in membrane modulating properties. Membrane activities of BAR domains are further modified and regulated by intramolecular or inter-subunit domains, by intermolecular protein interactions, and by posttranslational modifications. Rather than providing detailed cell biological information on single members of this superfamily, this review focuses on biochemical, biophysical, and structural aspects and on recent findings that paradigmatically promote our understanding of processes driven and modulated by BAR domains.

A novel in-frame deletion affecting the BAR domain of OPHN1 in a family with intellectual disability and hippocampal alterations

PubMed Central

Santos-Rebouças, Cíntia Barros; Belet, Stefanie; Guedes de Almeida, Luciana; Ribeiro, Márcia Gonçalves; Medina-Acosta, Enrique; Bahia, Paulo Roberto Valle; Alves da Silva, Antônio Francisco; Lima dos Santos, Flávia; Borges de Lacerda, Glenda Corrêa; Pimentel, Márcia Mattos Gonçalves; Froyen, Guy

2014-01-01

Oligophrenin-1 (OPHN1) is one of at least seven genes located on chromosome X that take part in Rho GTPase-dependent signaling pathways involved in X-linked intellectual disability (XLID). Mutations in OPHN1 were primarily described as an exclusive cause of non-syndromic XLID, but the re-evaluation of the affected individuals using brain imaging displayed fronto-temporal atrophy and cerebellar hypoplasia as neuroanatomical marks. In this study, we describe clinical, genetic and neuroimaging data of a three generation Brazilian XLID family co-segregating a novel intragenic deletion in OPHN1. This deletion results in an in-frame loss of exon 7 at transcription level (c.781_891del; r.487_597del), which is predicted to abolish 37 amino acids from the highly conserved N-terminal BAR domain of OPHN1. cDNA expression analysis demonstrated that the mutant OPHN1 transcript is stable and no abnormal splicing was observed. Features shared by the affected males of this family include neonatal hypotonia, strabismus, prominent root of the nose, deep set eyes, hyperactivity and instability/intolerance to frustration. Cranial MRI scans showed large lateral ventricles, vermis hypoplasia and cystic dilatation of the cisterna magna in all affected males. Interestingly, hippocampal alterations that have not been reported in patients with loss-of-function OPHN1 mutations were found in three affected individuals, suggesting an important function for the BAR domain in the hippocampus. This is the first description of an in-frame deletion within the BAR domain of OPHN1 and could provide new insights into the role of this domain in relation to brain and cognitive development or function. PMID:24105372

Contributions of F-BAR and SH2 domains of Fes protein tyrosine kinase for coupling to the FcepsilonRI pathway in mast cells.

PubMed

McPherson, Victor A; Everingham, Stephanie; Karisch, Robert; Smith, Julie A; Udell, Christian M; Zheng, Jimin; Jia, Zongchao; Craig, Andrew W B

2009-01-01

This study investigates the roles of Fer-CIP4 homology (FCH)-Bin/amphiphysin/Rvs (F-BAR) and SH2 domains of Fes protein tyrosine kinase in regulating its activation and signaling downstream of the high-affinity immunoglobulin G (IgE) receptor (FcepsilonRI) in mast cells. Homology modeling of the Fes F-BAR domain revealed conservation of some basic residues implicated in phosphoinositide binding (R113/K114). The Fes F-BAR can bind phosphoinositides and induce tubulation of liposomes in vitro. Mutation of R113/K114 to uncharged residues (RK/QQ) caused a significant reduction in phosphoinositide binding in vitro and a more diffuse cytoplasmic localization in transfected COS-7 cells. RBL-2H3 mast cells expressing full-length Fes carrying the RK/QQ mutation show defects in FcepsilonRI-induced Fes tyrosine phosphorylation and degranulation compared to cells expressing wild-type Fes. This correlated with reduced localization to Lyn kinase-containing membrane fractions for the RK/QQ mutant compared to wild-type Fes in mast cells. The Fes SH2 domain also contributes to Fes signaling in mast cells, via interactions with the phosphorylated FcepsilonRI beta chain and the actin regulatory protein HS1. We show that Fes phosphorylates C-terminal tyrosine residues in HS1 implicated in actin stabilization. Thus, coordinated actions of the F-BAR and SH2 domains of Fes allow for coupling to FcepsilonRI signaling and potential regulation the actin reorganization in mast cells.

The bar-halo interaction - I. From fundamental dynamics to revised N-body requirements

NASA Astrophysics Data System (ADS)

Weinberg, Martin D.; Katz, Neal

2007-02-01

A galaxy remains near equilibrium for most of its history. Only through resonances can non-axisymmetric features, such as spiral arms and bars, exert torques over large scales and change the overall structure of the galaxy. In this paper, we describe the resonant interaction mechanism in detail, derive explicit criteria for the particle number required to simulate these dynamical processes accurately using N-body simulations, and illustrate them with numerical experiments. To do this, we perform a direct numerical solution of perturbation theory, in short, by solving for each orbit in an ensemble and make detailed comparisons with N-body simulations. The criteria include: sufficient particle coverage in phase space near the resonance and enough particles to minimize gravitational potential fluctuations that will change the dynamics of the resonant encounter. These criteria are general in concept and can be applied to any dynamical interaction. We use the bar-halo interaction as our primary example owing to its technical simplicity and astronomical ubiquity. Some of our more surprising findings are as follows. First, the inner Lindblad like resonance, responsible for coupling the bar to the central halo cusp, requires more than equal-mass particles within the virial radius or inside the bar radius for a Milky Way like bar in a Navarro, Frenk & White profile. Secondly, orbits that linger near the resonance receive more angular momentum than orbits that move through the resonance quickly. Small-scale fluctuations present in state-of-the-art particle-particle simulations can knock orbits out of resonance, preventing them from lingering and, thereby, decrease the torque per orbit. This can be offset by the larger number of orbits affected by the resonance due to the diffusion. However, noise from orbiting substructure remains at least an order of magnitude too small to be of consequence. Applied to N-body simulations, the required particle numbers are sufficiently high

Dynamics of membrane nanotubes coated with I-BAR

NASA Astrophysics Data System (ADS)

Barooji, Younes F.; Rørvig-Lund, Andreas; Semsey, Szabolcs; Reihani, S. Nader S.; Bendix, Poul M.

2016-07-01

Membrane deformation is a necessary step in a number of cellular processes such as filopodia and invadopodia formation and has been shown to involve membrane shaping proteins containing membrane binding domains from the IRSp53-MIM protein family. In reconstituted membranes the membrane shaping domains can efficiently deform negatively charged membranes into tubules without any other proteins present. Here, we show that the IM domain (also called I-BAR domain) from the protein ABBA, forms semi-flexible nanotubes protruding into Giant Unilamellar lipid Vesicles (GUVs). By simultaneous quantification of tube intensity and tubular shape we find both the diameter and stiffness of the nanotubes. I-BAR decorated tubes were quantified to have a diameter of ~50 nm and exhibit no stiffening relative to protein free tubes of the same diameter. At high protein density the tubes are immobile whereas at lower density the tubes diffuse freely on the surface of the GUV. Bleaching experiments of the fluorescently tagged I-BAR confirmed that the mobility of the tubes correlates with the mobility of the I-BAR on the GUV membrane. Finally, at low density of I-BAR the protein upconcentrates within tubes protruding into the GUVs. This implies that I-BAR exhibits strong preference for negatively curved membranes.

Multiple voluminous sector collapses at Volcán Barú, Panama

NASA Astrophysics Data System (ADS)

Herrick, J. A.; Rose, W. I.

2010-12-01

Our recent work on Volcán Barú, an andesitic dome complex in Western Panama, has revealed a significant hazard from debris avalanches. Field observations of volcanic debris avalanche deposits and study of aerial photo data have revealed two avalanche units from Barú, the Barriles and the Caisán Deposits, both attributed to sector collapse of the western flank. Sherrod and others, 2007, also recognized this as one of the potential volcanic hazards of Panama's youngest volcanic center. The Barriles Deposit yielded two radiocarbon ages: 8590 ±50 ybp and 8000 ±30 ybp. The Caisán Deposit was also dated and is beyond the radiocarbon range (>43,000 ybp). From satellite imagery and field observations of distal hummocks, the total runout length of the Caisán deposit was ˜50 km covering 1180-km2. The Barriles Deposit extended to about 43 km. Despite heavy vegetation of the field area, 576-km2 were analyzed and over 4000 individual hummocks were digitized from aerial photography. Statistical analysis of hummock locations and geometries depict flow patterns over the entire debris fan and reflect the effects of underlying topography. The Barriles avalanche deposit has an estimated volume of 39 km3 to 61 km3 while the Caisán Deposit is slightly larger: 57 km3 to 64 km3. We conclude that debris avalanches of Volcán Barú are rare examples of unconfined volcanic debris avalanche deposits that rank among the world's most voluminous such as ancestral Mount Shasta, USA; Socompa, Chile/Argentina; and Shiveluch, Russia. Supported by the NSF Partnerships in International Research and Education Grant [0530109] this work is part of an on-going collaboration between the Michigan Tech Geology Department and Peace Corps. Reference: Sherrod, D.R., Vallance, J.W., Tapia Espinosa, A., and McGeehin, J.P., 2007, Volcán Barú eruptive history and volcano-hazards assessment, Open-File Report 2007-1401: Reston, VA, The U.S. Geological Survey, p. 33. A view East into the crater of Volcán

Modeling Membrane Deformations and Lipid Demixing upon Protein-Membrane Interaction: The BAR Dimer Adsorption

PubMed Central

Khelashvili, George; Harries, Daniel; Weinstein, Harel

2009-01-01

We use a self-consistent mean-field theory, designed to investigate membrane reshaping and lipid demixing upon interaction with proteins, to explore BAR domains interacting with large patches of lipid membranes of heterogeneous compositions. The computational model includes contributions to the system free energy from electrostatic interactions and elastic energies of the membrane, as well as salt and lipid mixing entropies. The results from our simulation of a single adsorbing Amphiphysin BAR dimer indicate that it is capable of stabilizing a significantly curved membrane. However, we predict that such deformations will occur only for membrane patches that have the inherent propensity for high curvature, reflected in the tendency to create local distortions that closely match the curvature of the BAR dimer itself. Such favorable preconditioning for BAR-membrane interaction may be the result of perturbations such as local lipid demixing induced by the interaction, or of a prior insertion of the BAR domain's amphiphatic N-helix. From our simulations it appears that local segregation of charged lipids under the influence of the BAR dimer cannot produce high enough asymmetry between bilayer leaflets to induce significant bending. In the absence of additional energy contributions that favor membrane asymmetry, the membrane will remain nearly flat upon single BAR dimer adsorption, relative to the undulation expected from thermal fluctuations. Thus, we conclude that the N-helix insertions have a critical mechanistic role in the local perturbation and curving of the membrane, which is then stabilized by the electrostatic interaction with the BAR dimer. We discuss how these results can be used to estimate the tendency of BARs to bend membranes in terms of a spatially nonisotropic spontaneous curvature. PMID:19751667

Two flagellar BAR domain proteins in Trypanosoma brucei with stage-specific regulation

PubMed Central

Cicova, Zdenka; Dejung, Mario; Skalicky, Tomas; Eisenhuth, Nicole; Hanselmann, Steffen; Morriswood, Brooke; Figueiredo, Luisa M.; Butter, Falk; Janzen, Christian J.

2016-01-01

Trypanosomes are masters of adaptation to different host environments during their complex life cycle. Large-scale proteomic approaches provide information on changes at the cellular level, and in a systematic way. However, detailed work on single components is necessary to understand the adaptation mechanisms on a molecular level. Here, we have performed a detailed characterization of a bloodstream form (BSF) stage-specific putative flagellar host adaptation factor Tb927.11.2400, identified previously in a SILAC-based comparative proteome study. Tb927.11.2400 shares 38% amino acid identity with TbFlabarin (Tb927.11.2410), a procyclic form (PCF) stage-specific flagellar BAR domain protein. We named Tb927.11.2400 TbFlabarin-like (TbFlabarinL), and demonstrate that it originates from a gene duplication event, which occurred in the African trypanosomes. TbFlabarinL is not essential for the growth of the parasites under cell culture conditions and it is dispensable for developmental differentiation from BSF to the PCF in vitro. We generated TbFlabarinL-specific antibodies, and showed that it localizes in the flagellum. Co-immunoprecipitation experiments together with a biochemical cell fractionation suggest a dual association of TbFlabarinL with the flagellar membrane and the components of the paraflagellar rod. PMID:27779220

Contributions of F-BAR and SH2 Domains of Fes Protein Tyrosine Kinase for Coupling to the FcɛRI Pathway in Mast Cells▿ †

PubMed Central

McPherson, Victor A.; Everingham, Stephanie; Karisch, Robert; Smith, Julie A.; Udell, Christian M.; Zheng, Jimin; Jia, Zongchao; Craig, Andrew W. B.

2009-01-01

This study investigates the roles of Fer-CIP4 homology (FCH)-Bin/amphiphysin/Rvs (F-BAR) and SH2 domains of Fes protein tyrosine kinase in regulating its activation and signaling downstream of the high-affinity immunoglobulin G (IgE) receptor (FcɛRI) in mast cells. Homology modeling of the Fes F-BAR domain revealed conservation of some basic residues implicated in phosphoinositide binding (R113/K114). The Fes F-BAR can bind phosphoinositides and induce tubulation of liposomes in vitro. Mutation of R113/K114 to uncharged residues (RK/QQ) caused a significant reduction in phosphoinositide binding in vitro and a more diffuse cytoplasmic localization in transfected COS-7 cells. RBL-2H3 mast cells expressing full-length Fes carrying the RK/QQ mutation show defects in FcɛRI-induced Fes tyrosine phosphorylation and degranulation compared to cells expressing wild-type Fes. This correlated with reduced localization to Lyn kinase-containing membrane fractions for the RK/QQ mutant compared to wild-type Fes in mast cells. The Fes SH2 domain also contributes to Fes signaling in mast cells, via interactions with the phosphorylated FcɛRI β chain and the actin regulatory protein HS1. We show that Fes phosphorylates C-terminal tyrosine residues in HS1 implicated in actin stabilization. Thus, coordinated actions of the F-BAR and SH2 domains of Fes allow for coupling to FcɛRI signaling and potential regulation the actin reorganization in mast cells. PMID:19001085

F-BAR family proteins, emerging regulators for cell membrane dynamic changes-from structure to human diseases.

PubMed

Liu, Suxuan; Xiong, Xinyu; Zhao, Xianxian; Yang, Xiaofeng; Wang, Hong

2015-05-09

Eukaryotic cell membrane dynamics change in curvature during physiological and pathological processes. In the past ten years, a novel protein family, Fes/CIP4 homology-Bin/Amphiphysin/Rvs (F-BAR) domain proteins, has been identified to be the most important coordinators in membrane curvature regulation. The F-BAR domain family is a member of the Bin/Amphiphysin/Rvs (BAR) domain superfamily that is associated with dynamic changes in cell membrane. However, the molecular basis in membrane structure regulation and the biological functions of F-BAR protein are unclear. The pathophysiological role of F-BAR protein is unknown. This review summarizes the current understanding of structure and function in the BAR domain superfamily, classifies F-BAR family proteins into nine subfamilies based on domain structure, and characterizes F-BAR protein structure, domain interaction, and functional relevance. In general, F-BAR protein binds to cell membrane via F-BAR domain association with membrane phospholipids and initiates membrane curvature and scission via Src homology-3 (SH3) domain interaction with its partner proteins. This process causes membrane dynamic changes and leads to seven important cellular biological functions, which include endocytosis, phagocytosis, filopodium, lamellipodium, cytokinesis, adhesion, and podosome formation, via distinct signaling pathways determined by specific domain-binding partners. These cellular functions play important roles in many physiological and pathophysiological processes. We further summarize F-BAR protein expression and mutation changes observed in various diseases and developmental disorders. Considering the structure feature and functional implication of F-BAR proteins, we anticipate that F-BAR proteins modulate physiological and pathophysiological processes via transferring extracellular materials, regulating cell trafficking and mobility, presenting antigens, mediating extracellular matrix degradation, and transmitting

Optimizing purification process of MIM-I-BAR domain by introducing atomic force microscope and dynamics simulations.

PubMed

Zhang, Yue; Lou, Zhichao; Lin, Xubo; Wang, Qiwei; Cao, Meng; Gu, Ning

2017-09-01

MIM (missing in metastasis) is a member of I-BAR (inverse BAR) domain protein family, which functions as a putative metastasis suppressor. However, methods of gaining high purity MIM-I-BAR protein are barely reported. Here, by optimizing the purification process including changing the conditions of cell lysate and protein elution, we successfully purified MIM protein. The purity of the obtained protein was up to ∼90%. High-resolution atomic force microscope (AFM) provides more visual images, ensuring that we can observe the microenvironment around the target protein, as well as the conformations of the purification products following each purification process. MIM protein with two different sizes were observed on mica surface with AFM. Combining with molecular dynamics simulations, these molecules were revealed as MIM monomer and dimer. Furthermore, our study attaches importance to the usage of imidazole with suitable concentrations during the affinity chromatography process, as well as the removal of excessive imidazole after the affinity chromatography process. All these results indicate that the method described here was successful in purifying MIM protein and maintaining their natural properties, and is supposed to be used to purify other proteins with low solubility. Copyright © 2017. Published by Elsevier B.V.

Miscut dependent surface evolution in the process of N-polar GaN(000 1 bar) growth under N-rich condition

NASA Astrophysics Data System (ADS)

Krzyżewski, Filip; Załuska-Kotur, Magdalena A.; Turski, Henryk; Sawicka, Marta; Skierbiszewski, Czesław

2017-01-01

The evolution of surface morphology during the growth of N-polar (000 1 bar) GaN under N-rich conditions is studied by kinetic Monte Carlo (kMC) simulations for two substrates miscuts 2° and 4°. The results are compared with experimentally observed surface morphologies of (000 1 bar) GaN layers grown by plasma-assisted molecular beam epitaxy. The proposed kMC two-component model of GaN(000 1 bar) surface where both types of atoms, nitrogen and gallium, attach to the surface and diffuse independently shows that at relatively high rates of the step flow (miscut angle < 2 °) the low mobility of gallium adatoms causes surface instabilities and leads to experimentally observed roughening while for low rates of the step flow (miscut 4°), smooth surface can be obtained. In the presence of almost immobile nitrogen atoms under N-rich conditions crystal growth is realized by the process of two-dimensional island nucleation and coalescence. Larger crystal miscut, lower growth rate or higher temperature results in similar effect of the surface smoothening. We show that the surface also smoothens for the growth conditions with very high N-excess. In the presence of large number of nitrogen atoms the mobility of gallium atoms changes locally thus providing easier coalescence of separated island.

Interaction of real and virtual p p bar pairs in J / ψ → p p bar γ (ρ , ω) decays

NASA Astrophysics Data System (ADS)

Milstein, A. I.; Salnikov, S. G.

2017-10-01

The p p bar invariant mass spectra of the processes J / ψ → p p bar ω, J / ψ → p p bar ρ, and J / ψ → p p bar γ close to the p p bar threshold are calculated by means of the N N bar optical potential. The potential model for N N bar interaction in the S10 state is proposed. The parameters of the model are obtained by fitting the cross section of N N bar scattering together with the p p bar invariant mass spectra of the J / ψ decays. Good agreement with the available experimental data is achieved. Using our potential and the Green's function approach we also describe the peak in the η‧π+π- invariant mass spectrum in the decay J / ψ → γη‧π+π- in the energy region near the N N bar threshold.

Performances of RPCs in the BaBar experiment

NASA Astrophysics Data System (ADS)

Anulli, F.; Baldini, R.; Band, H.; Bionta, R.; Brau, J.; Brigljevic, V.; Buzzo, A.; Calcaterra, A.; Carpinelli, M.; Cartaro, T.; Cavallo, N.; Crosetti, G.; De Nardo, G.; De Sangro, R.; Eichenbaum, A.; Falciai, D.; Fabozzi, F.; Ferroni, F.; Finocchiaro, G.; Forti, F.; Frey, R.; Johnson, J.; Gatto, C.; Grauges-Pous, E.; Iwasaki, M.; Lange, D.; Lista, L.; Lo Vetere, M.; Lu, C.; Neal, H.; Neri, N.; Macri, M.; Messener, B.; Monge, M. R.; Moore, T.; Morganti, S.; Palano, A.; Paoloni, E.; Paolucci, P.; Passaggio, S.; Pastore, F.; Patrignani, C.; Patteri, P.; Peruzzi, I.; Piccolo, D.; Piccolo, M.; Piredda, G.; Pompili, A.; Robutti, E.; Roodman, A.; Santroni, A.; Sciacca, C.; Sinev, N.; Soha, A.; Storm, D.; Tosi, S.; Va'vra, J.; Xie, Y.; Wright, D.; Wisniewski, W.

2003-12-01

The BaBar experiment uses a big system based on RPC detectors to discriminate muons from pions and to identify neutral hadrons. About 2000 m2 of RPC chambers have been working at SLAC since the end of 1998. We report on the performances of the RPC chambers focusing on new problems discovered in the RPC behaviour. These problems started very soon after the installation of the chambers on the detector when the high-ambient temperature triggered an increase of dark currents inside the chambers and a reduction of the efficiency. Careful analysis of the BaBar data and dedicated R&D efforts in the laboratory have helped to identify the main source of the trouble in the linseed oil varnish on the bakelite electrodes.

Polydimethylsiloxane/MIL-100(Fe) coated stir bar sorptive extraction-high performance liquid chromatography for the determination of triazines in environmental water samples.

PubMed

Lei, Yun; Chen, Beibei; You, Linna; He, Man; Hu, Bin

2017-12-01

Polydimethylsiloxane (PDMS)/MIL-100(Fe) coated stir bar was prepared by sol gel technique, and good preparation reproducibility was achieved with relative standard deviations (RSDs) ranging from 2.6% to 7.5% (n=7) and 3.6% to 10.8% (n=7) for bar-to-bar and batch-to-batch, respectively. Compared with commercial PDMS coated stir bar (Gerstel) and PEG coated stir bar (Gerstel), the prepared PDMS/MIL-100(Fe) stir bar showed better extraction efficiency for target triazines compounds. It also exhibited relatively fast extraction/desorption kinetics and long lifespan. Based on it, a method of PDMS/MIL-100(Fe) coated stir bar sorptive extraction (SBSE)-high performance liquid chromatography-ultraviolet detector (HPLC-UV) was developed for the determination of six triazines (simazine, atrazine, prometon, ametryn, prometryne and prebane) in environmental water samples. Several parameters affecting SBSE of six target triazines including extraction time, stirring rate, sample pH, ionic strength, desorption solvent and desorption time were investigated. Under the optimal experimental conditions, the limits of detection (LODs, S/N=3) were found to be in the range of 0.021-0.079μgL -1 . The repeatability RSDs were in the range of 2.3-6.3% (n=7, c=0.5μgL -1 ) and the enrichment factors (EFs) ranged from 51.1 to 102-fold (theoretical EF was 200-fold). The proposed method was applied to the analysis of target triazines in environmental water samples, with recoveries of 98.0-118% and 94.0-107% for spiked East Lake water and local pond water samples, respectively. Copyright © 2017. Published by Elsevier B.V.

Membrane curvature and its generation by BAR proteins

PubMed Central

Mim, Carsten; Unger, Vinzenz M

2012-01-01

Membranes are flexible barriers that surround the cell and its compartments. To execute vital functions such as locomotion or receptor turnover, cells need to control the shapes of their membranes. In part, this control is achieved through membrane-bending proteins, such as the bin/amphiphysin/rvs domain (BAR) proteins. Many open questions remain about the mechanisms by which membrane-bending proteins function. Addressing this shortfall, recent structures of BAR protein:membrane complexes support existing mechanistic models, but also produced novel insights into how BAR-domain proteins sense, stabilize and generate curvature. Here we review these recent findings, focusing on how BAR proteins interact with the membrane, and how the resulting scaffold structures might aid the recruitment of other proteins to the sites where membranes are bent. PMID:23058040

The BaBar detector: Upgrades, operation and performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aubert, B.; Barate, R.; Boutigny, D.

2013-11-01

The BaBar detector operated successfully at the PEP-II asymmetric e+e- collider at the SLAC National Accelerator Laboratory from 1999 to 2008. This report covers upgrades, operation, and performance of the collider and the detector systems, as well as the trigger, online and offline computing, and aspects of event reconstruction since the beginning of data taking.

Performance studies of the P barANDA planar GEM-tracking detector in physics simulations

NASA Astrophysics Data System (ADS)

Divani Veis, Nazila; Firoozabadi, Mohammad M.; Karabowicz, Radoslaw; Maas, Frank; Saito, Takehiko R.; Voss, Bernd; ̅PANDA Gem-Tracker Subgroup

2018-03-01

The P barANDA experiment will be installed at the future facility for antiproton and ion research (FAIR) in Darmstadt, Germany, to study events from the annihilation of protons and antiprotons. The P barANDA detectors can cover a wide physics program about baryon spectroscopy and nucleon structure as well as the study of hadrons and hypernuclear physics including the study of excited hyperon states. One very specific feature of most hyperon ground states is the long decay length of several centimeters in the forward direction. The central tracking detectors of the P barANDA setup are not sufficiently optimized for these long decay lengths. Therefore, using a set of the planar GEM-tracking detectors in the forward region of interest can improve the results in the hyperon physics-benchmark channel. The current conceptual designed P barANDA GEM-tracking stations contribute the measurement of the particles emitted in the polar angles between about 2 to 22 degrees. For this designed detector performance and acceptance, studies have been performed using one of the important hyperonic decay channel p bar p → Λ bar Λ → p bar pπ+π- in physics simulations. The simulations were carried out using the PandaRoot software packages based on the FairRoot framework.

Gaseous Structures in Barred Galaxies: Effects of the Bar Strength

NASA Astrophysics Data System (ADS)

Kim, Woong-Tae; Seo, Woo-Young; Kim, Yonghwi

2012-10-01

Using hydrodynamic simulations, we investigate the physical properties of gaseous substructures in barred galaxies and their relationships with the bar strength. The gaseous medium is assumed to be isothermal and unmagnetized. The bar potential is modeled as a Ferrers prolate with index n. To explore situations with differing bar strength, we vary the bar mass f bar relative to the spheroidal component as well as its aspect ratio { R}. We derive expressions as functions of f bar and { R} for the bar strength Qb and the radius r(Qb ) where the maximum bar torque occurs. When applied to observations, these expressions suggest that bars in real galaxies are most likely to have f bar ~ 0.25-0.50 and n <~ 1. Dust lanes approximately follow one of the x 1-orbits and tend to be straighter under a stronger and more elongated bar, but are insensitive to the presence of self-gravity. A nuclear ring of a conventional x 2 type forms only when the bar is not so massive or elongated. The radius of an x 2-type ring is generally smaller than the inner Lindblad resonance, decreases systematically with increasing Qb , and is slightly larger when self-gravity is included. This is evidence that the ring position is not determined by the resonance, but instead by the amount of angular momentum loss at dust-lane shocks. Nuclear spirals exist only when the ring is of the x 2 type and is sufficiently large in size. Unlike the other features, nuclear spirals are transient in that they start out being tightly wound and weak, and then, due to the nonlinear effect, unwind and become stronger until they turn into shocks, with an unwinding rate that is higher for larger Qb . The mass inflow rate to the galaxy center is found to be less than 0.01 M ⊙ yr-1 for models with Qb <~ 0.2, while becoming larger than 0.1 M ⊙ yr-1 when Qb >~ 0.2 and self-gravity is included.

Evaluation of a method for the simultaneous quantification of N-nitrosamines in water samples based on stir bar sorptive extraction combined with high-performance liquid chromatography and diode array detection.

PubMed

Talebpour, Zahra; Rostami, Simindokht; Rezadoost, Hassan

2015-05-01

A simple, sensitive, and reliable procedure based on stir bar sorptive extraction coupled with high-performance liquid chromatography was applied to simultaneously extract and determine three semipolar nitrosamines including N-nitrosodibutylamine, N-nitrosodiphenylamine, and N-nitrosodicyclohexylamine. To achieve the optimum conditions, the effective parameters on the extraction efficiency including desorption solvent and time, ionic strength of sample, extraction time, and sample volume were systematically investigated. The optimized extraction procedure was carried out by stir bars coated with polydimethylsiloxane. Under optimum extraction conditions, the performance of the proposed method was studied. The linear dynamic range was obtained in the range of 0.95-1000 ng/mL (r = 0.9995), 0.26-1000 ng/mL (r = 0.9988) and both 0.32-100 ng/mL (r = 0.9999) and 100-1000 ng/mL (r = 0.9998) with limits of detection of 0.28, 0.08, and 0.09 ng/mL for N-nitrosodibutylamine, N-nitrosodiphenylamine, and N-nitrosodicyclohexylamine, respectively. The average recoveries were obtained >81%, and the reproducibility of the proposed method presented as intra- and interday precision were also found with a relative standard deviation <6%. Finally, the proposed method was successfully applied to the determination of trace amounts of selected nitrosamines in various water and wastewater samples and the obtained results were confirmed using mass spectrometry. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Bologna Annotation Resource (BAR 3.0): improving protein functional annotation

PubMed Central

Casadio, Rita

2017-01-01

Abstract BAR 3.0 updates our server BAR (Bologna Annotation Resource) for predicting protein structural and functional features from sequence. We increase data volume, query capabilities and information conveyed to the user. The core of BAR 3.0 is a graph-based clustering procedure of UniProtKB sequences, following strict pairwise similarity criteria (sequence identity ≥40% with alignment coverage ≥90%). Each cluster contains the available annotation downloaded from UniProtKB, GO, PFAM and PDB. After statistical validation, GO terms and PFAM domains are cluster-specific and annotate new sequences entering the cluster after satisfying similarity constraints. BAR 3.0 includes 28 869 663 sequences in 1 361 773 clusters, of which 22.2% (22 241 661 sequences) and 47.4% (24 555 055 sequences) have at least one validated GO term and one PFAM domain, respectively. 1.4% of the clusters (36% of all sequences) include PDB structures and the cluster is associated to a hidden Markov model that allows building template-target alignment suitable for structural modeling. Some other 3 399 026 sequences are singletons. BAR 3.0 offers an improved search interface, allowing queries by UniProtKB-accession, Fasta sequence, GO-term, PFAM-domain, organism, PDB and ligand/s. When evaluated on the CAFA2 targets, BAR 3.0 largely outperforms our previous version and scores among state-of-the-art methods. BAR 3.0 is publicly available and accessible at http://bar.biocomp.unibo.it/bar3. PMID:28453653

Predicting detection performance with model observers: Fourier domain or spatial domain?

PubMed

Chen, Baiyu; Yu, Lifeng; Leng, Shuai; Kofler, James; Favazza, Christopher; Vrieze, Thomas; McCollough, Cynthia

2016-02-27

The use of Fourier domain model observer is challenged by iterative reconstruction (IR), because IR algorithms are nonlinear and IR images have noise texture different from that of FBP. A modified Fourier domain model observer, which incorporates nonlinear noise and resolution properties, has been proposed for IR and needs to be validated with human detection performance. On the other hand, the spatial domain model observer is theoretically applicable to IR, but more computationally intensive than the Fourier domain method. The purpose of this study is to compare the modified Fourier domain model observer to the spatial domain model observer with both FBP and IR images, using human detection performance as the gold standard. A phantom with inserts of various low contrast levels and sizes was repeatedly scanned 100 times on a third-generation, dual-source CT scanner at 5 dose levels and reconstructed using FBP and IR algorithms. The human detection performance of the inserts was measured via a 2-alternative-forced-choice (2AFC) test. In addition, two model observer performances were calculated, including a Fourier domain non-prewhitening model observer and a spatial domain channelized Hotelling observer. The performance of these two mode observers was compared in terms of how well they correlated with human observer performance. Our results demonstrated that the spatial domain model observer correlated well with human observers across various dose levels, object contrast levels, and object sizes. The Fourier domain observer correlated well with human observers using FBP images, but overestimated the detection performance using IR images.

Predicting detection performance with model observers: Fourier domain or spatial domain?

PubMed Central

Chen, Baiyu; Yu, Lifeng; Leng, Shuai; Kofler, James; Favazza, Christopher; Vrieze, Thomas; McCollough, Cynthia

2016-01-01

The use of Fourier domain model observer is challenged by iterative reconstruction (IR), because IR algorithms are nonlinear and IR images have noise texture different from that of FBP. A modified Fourier domain model observer, which incorporates nonlinear noise and resolution properties, has been proposed for IR and needs to be validated with human detection performance. On the other hand, the spatial domain model observer is theoretically applicable to IR, but more computationally intensive than the Fourier domain method. The purpose of this study is to compare the modified Fourier domain model observer to the spatial domain model observer with both FBP and IR images, using human detection performance as the gold standard. A phantom with inserts of various low contrast levels and sizes was repeatedly scanned 100 times on a third-generation, dual-source CT scanner at 5 dose levels and reconstructed using FBP and IR algorithms. The human detection performance of the inserts was measured via a 2-alternative-forced-choice (2AFC) test. In addition, two model observer performances were calculated, including a Fourier domain non-prewhitening model observer and a spatial domain channelized Hotelling observer. The performance of these two mode observers was compared in terms of how well they correlated with human observer performance. Our results demonstrated that the spatial domain model observer correlated well with human observers across various dose levels, object contrast levels, and object sizes. The Fourier domain observer correlated well with human observers using FBP images, but overestimated the detection performance using IR images. PMID:27239086

Trend of change in retentive force for bar attachments with different materials.

PubMed

Saito, Marie; Kanazawa, Manabu; Takahashi, Hidekazu; Uo, Motohiro; Minakuchi, Shunsuke

2014-12-01

Attachment wear can decrease the retentive force of 2-implant overdentures (2-IODs). The purpose of this in vitro study was to investigate the trend of change in retentive force for 6 different bar attachments during dislodgement. Round and Dolder bars were made of platinum-added gold alloy (PGA), cobalt chromium alloy (Co-Cr), and commercially pure titanium grade IV (Ti). Clips were made of PGA. Retentive force was measured during 7200 dislodging cycles. Simple linear regression analysis was performed in order to investigate the relationship between number of cycles and retentive force (P<.05). Subsequently, wear debris was analyzed, and the surface of the attachments was observed. The retentive force of the Co-Cr round bar attachment (CoCr-R) increased from 57.5 N to 68.3 N and the Ti round bar attachment (Ti-R) from 54.8 N to 59.7 N. However, the retentive force of the PGA round bar attachment (PGA-R) decreased from 69.3 N to 64.0 N. A positive relationship was found between the number of cycles and the retentive force of both CoCr-R and Ti-R. The composition of the wear debris was almost the same as for PGA. For the Dolder bar attachment, no changes were seen in retentive force (between 7.0 N to 12.0 N). For the round bar attachment, the PGA clip and PGA bar showed wear. The retentive force of PGA-R slightly decreased. The retentive force of CoCr-R and Ti-R tended to increase. For the Dolder bar attachment, all 3 types of bar attachment showed no wear. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

The Bologna Annotation Resource (BAR 3.0): improving protein functional annotation.

PubMed

Profiti, Giuseppe; Martelli, Pier Luigi; Casadio, Rita

2017-07-03

BAR 3.0 updates our server BAR (Bologna Annotation Resource) for predicting protein structural and functional features from sequence. We increase data volume, query capabilities and information conveyed to the user. The core of BAR 3.0 is a graph-based clustering procedure of UniProtKB sequences, following strict pairwise similarity criteria (sequence identity ≥40% with alignment coverage ≥90%). Each cluster contains the available annotation downloaded from UniProtKB, GO, PFAM and PDB. After statistical validation, GO terms and PFAM domains are cluster-specific and annotate new sequences entering the cluster after satisfying similarity constraints. BAR 3.0 includes 28 869 663 sequences in 1 361 773 clusters, of which 22.2% (22 241 661 sequences) and 47.4% (24 555 055 sequences) have at least one validated GO term and one PFAM domain, respectively. 1.4% of the clusters (36% of all sequences) include PDB structures and the cluster is associated to a hidden Markov model that allows building template-target alignment suitable for structural modeling. Some other 3 399 026 sequences are singletons. BAR 3.0 offers an improved search interface, allowing queries by UniProtKB-accession, Fasta sequence, GO-term, PFAM-domain, organism, PDB and ligand/s. When evaluated on the CAFA2 targets, BAR 3.0 largely outperforms our previous version and scores among state-of-the-art methods. BAR 3.0 is publicly available and accessible at http://bar.biocomp.unibo.it/bar3. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Fuchs-Kliewer phonons of H-covered and clean GaN(1 1 bar 00)

NASA Astrophysics Data System (ADS)

Rink, M.; Himmerlich, M.; Krischok, S.; Kröger, J.

2018-01-01

Inelastic electron scattering is used to study surface phonon polaritons on H-covered and clean GaN(1 1 bar 00) surfaces. The Fuchs-Kliewer phonon of GaN(1 1 bar 00) -H gives rise to characteristic signatures of its single and multiple excitation in specular electron energy loss spectra. The loss intensities for multi-phonon scattering processes decrease according to a Poisson distribution. Vibrational spectra of this surface are invariant on the time scale of days reflecting its chemical passivation by the H layer. In contrast, vibrational spectra of pristine GaN(1 1 bar 00) are subject to a pronounced temporal evolution where spectroscopic weight is gradually shifted towards the multiple excitation of the Fuchs-Kliewer phonon. As a consequence, the monotonous decrease of the cross section for multiple quantum excitation as observed for the H-covered surface is not applicable. This remarkable effect is particularly strong in spectra acquired at low primary energies of incident electrons, which hints at processes occurring in the very surface region. Scenarios that may contribute to these observations are discussed.

Scale dependence of open c{\\bar{c}} and b{\\bar{b}} production in the low x region

NASA Astrophysics Data System (ADS)

Oliveira, E. G. de; Martin, A. D.; Ryskin, M. G.

2017-03-01

The `optimal' factorization scale μ _0 is calculated for open heavy quark production. We find that the optimal value is μ _F=μ _0˜eq 0.85√{p^2_T+m_Q^2} ; a choice which allows us to resum the double-logarithmic, (α _s ln μ ^2_F ln (1/x))^n corrections (enhanced at LHC energies by large values of ln (1/x)) and to move them into the incoming parton distributions, PDF(x,μ _0^2). Besides this result for the single inclusive cross section (corresponding to an observed heavy quark of transverse momentum p_T), we also determined the scale for processes where the acoplanarity can be measured; that is, events where the azimuthal angle between the quark and the antiquark may be determined experimentally. Moreover, we discuss the important role played by the 2→ 2 subprocesses, gg→ Q\\bar{Q} at NLO and higher orders. In summary, we achieve a better stability of the QCD calculations, so that the data on c{\\bar{c}} and b{\\bar{b}} production can be used to further constrain the gluons in the small x, relatively low scale, domain, where the uncertainties of the global analyses are large at present.

Estimating non-circular motions in barred galaxies using numerical N-body simulations

NASA Astrophysics Data System (ADS)

Randriamampandry, T. H.; Combes, F.; Carignan, C.; Deg, N.

2015-12-01

The observed velocities of the gas in barred galaxies are a combination of the azimuthally averaged circular velocity and non-circular motions, primarily caused by gas streaming along the bar. These non-circular flows must be accounted for before the observed velocities can be used in mass modelling. In this work, we examine the performance of the tilted-ring method and the DISKFIT algorithm for transforming velocity maps of barred spiral galaxies into rotation curves (RCs) using simulated data. We find that the tilted-ring method, which does not account for streaming motions, under-/overestimates the circular motions when the bar is parallel/perpendicular to the projected major axis. DISKFIT, which does include streaming motions, is limited to orientations where the bar is not aligned with either the major or minor axis of the image. Therefore, we propose a method of correcting RCs based on numerical simulations of galaxies. We correct the RC derived from the tilted-ring method based on a numerical simulation of a galaxy with similar properties and projections as the observed galaxy. Using observations of NGC 3319, which has a bar aligned with the major axis, as a test case, we show that the inferred mass models from the uncorrected and corrected RCs are significantly different. These results show the importance of correcting for the non-circular motions and demonstrate that new methods of accounting for these motions are necessary as current methods fail for specific bar alignments.

Determination of phenol compounds in surface water matrices by bar adsorptive microextraction-high performance liquid chromatography-diode array detection.

PubMed

Neng, Nuno R; Nogueira, José M F

2014-07-03

Bar adsorptive microextraction combined with liquid desorption followed by high performance liquid chromatography with diode array detection (BAµE-LD/HPLC-DAD) is proposed for the determination of trace levels of five phenol compounds (3-nitrophenol, 4-nitrophenol, bisphenol-A, 4-n-octylphenol and 4-n-nonylphenol) in surface water matrices. By using a polystyrene-divinylbenzene copolymer (PS-DVB) sorbent phase, high selectivity and efficiency is achieved even against polydimethylsiloxane through stir bar sorptive extraction. Assays performed by BAµE(PS-DVB)-LD/HPLC-DAD on 25 mL water samples spiked at the 10.0 µg/L levels yielded recoveries over 88.0%±5.7% for all five analytes, under optimized experimental conditions. The analytical performance showed good precision (RSD<15%), detection limits of 0.25 µg/L and linear dynamic ranges (1.0-25.0 μg/L) with determination coefficient higher than 0.9904. By using the standard addition method, the application of the present method to surface water matrices allowed very good performances at the trace level. The proposed methodology proved to be a suitable alternative to monitor phenol compounds in surface water matrices, showing to be easy to implement, reliable, sensitive and requiring a low sample volume.

Oligomerization but Not Membrane Bending Underlies the Function of Certain F-BAR Proteins in Cell Motility and Cytokinesis.

PubMed

McDonald, Nathan A; Vander Kooi, Craig W; Ohi, Melanie D; Gould, Kathleen L

2015-12-21

F-BAR proteins function in diverse cellular processes by linking membranes to the actin cytoskeleton. Through oligomerization, multiple F-BAR domains can bend membranes into tubules, though the physiological importance of F-BAR-to-F-BAR assemblies is not yet known. Here, we investigate the F-BAR domain of the essential cytokinetic scaffold, Schizosaccharomyces pombe Cdc15, during cytokinesis. Challenging a widely held view that membrane deformation is a fundamental property of F-BARs, we report that the Cdc15 F-BAR binds, but does not deform, membranes in vivo or in vitro, and six human F-BAR domains-including those from Fer and RhoGAP4-share this property. Nevertheless, tip-to-tip interactions between F-BAR dimers are critical for Cdc15 oligomerization and high-avidity membrane binding, stabilization of contractile ring components at the medial cortex, and the fidelity of cytokinesis. F-BAR oligomerization is also critical for Fer and RhoGAP4 physiological function, demonstrating its broad importance to F-BAR proteins that function without membrane bending. Copyright © 2015 Elsevier Inc. All rights reserved.

Enabling Narrow(est) IWA Coronagraphy with STIS BAR5 and BAR10 Occulters

NASA Astrophysics Data System (ADS)

Schneider, Glenn; Gaspar, Andras; Debes, John; Gull, Theodore; Hines, Dean; Apai, Daniel; Rieke, George

2017-09-01

The Space Telescope Imaging Spectrograph's (STIS) BAR5 coronagraphic occulter was designed to provide high-contrast, visible-light, imaging in close (> 0.15") angular proximity to bright point-sources. We explored and verified the functionality and utility of the BAR5 occulter. We also investigated, and herein report on, the use of the BAR10 rounded corners as narrow-angle occulters and compare IWA vs. contrast performance for the BAR5, BAR10, and Wedge occulters. With that, we provide recommendations for the most efficacious BAR5 and BAR10 use on-orbit in support of GO science.

Fast strain wave induced magnetization changes in long cobalt bars: Domain motion versus coherent rotation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, S.; Adenwalla, S., E-mail: sadenwalla1@unl.edu; Borchers, J. A.

2015-02-14

A high frequency (88 MHz) traveling strain wave on a piezoelectric substrate is shown to change the magnetization direction in 40 μm wide Co bars with an aspect ratio of 10{sup 3}. The rapidly alternating strain wave rotates the magnetization away from the long axis into the short axis direction, via magnetoelastic coupling. Strain-induced magnetization changes have previously been demonstrated in ferroelectric/ferromagnetic heterostructures, with excellent fidelity between the ferromagnet and the ferroelectric domains, but these experiments were limited to essentially dc frequencies. Both magneto-optical Kerr effect and polarized neutron reflectivity confirm that the traveling strain wave does rotate the magnetization awaymore » from the long axis direction and both yield quantitatively similar values for the rotated magnetization. An investigation of the behavior of short axis magnetization with increasing strain wave amplitude on a series of samples with variable edge roughness suggests that the magnetization reorientation that is seen proceeds solely via coherent rotation. Polarized neutron reflectivity data provide direct experimental evidence for this model. This is consistent with expectations that domain wall motion cannot track the rapidly varying strain.« less

Comparative study of (0001) and (11\\bar{2}2) InGaN based light emitting diodes

NASA Astrophysics Data System (ADS)

Pristovsek, Markus; Humphreys, Colin J.; Bauer, Sebastian; Knab, Manuel; Thonke, Klaus; Kozlowski, Grzegorz; O'Mahony, Donagh; Maaskant, Pleun; Corbett, Brian

2016-05-01

We have systematically investigated the doping of (11\\bar{2}2) with Si and Mg by metal-organic vapour phase epitaxy for light emitting diodes (LEDs). By Si doping of GaN we reached electron concentrations close to 1020 cm-3, but the topography degrades above mid 1019 cm-3. By Mg doping we reached hole concentrations close to 5 × 1017 cm-3, using Mg partial pressures about 3× higher than those for (0001). Exceeding the maximum Mg partial pressure led to a quick degradation of the sample. Low resistivities as well as high hole concentrations required a growth temperature of 900 °C or higher. At optimised conditions the electrical properties as well as the photoluminescence of (11\\bar{2}2) p-GaN were similar to (0001) p-GaN. The best ohmic p-contacts were achieved by NiAg metallisation. A single quantum well LED emitting at 465 nm was realised on (0001) and (11\\bar{2}2). Droop (sub-linear increase of the light output power) occurred at much higher current densities on (11\\bar{2}2). However, the light output of the (0001) LED was higher than that of (11\\bar{2}2) until deep in the droop regime. Our LEDs as well as those in the literature indicate a reduction in efficiency from (0001) over semi-polar to non-polar orientations. We propose that reduced fields open a loss channel for carriers.

Polyaniline/cyclodextrin composite coated stir bar sorptive extraction combined with high performance liquid chromatography-ultraviolet detection for the analysis of trace polychlorinated biphenyls in environmental waters.

PubMed

Lei, Yun; He, Man; Chen, Beibei; Hu, Bin

2016-04-01

A novel polyaniline/α-cyclodextrin (PANI/α-CD) composite coated stir bar was prepared by sol-gel process for the analysis of polychlorinated biphenyls (PCBs) in this work. The preparation reproducibility of the PANI/α-CD-coated stir bar was good, with relative standard deviations (RSDs) ranging from 2.3% to 3.7% (n=7) and 2.0% to 3.8% (n=7) for bar to bar and batch to batch, respectively. Based on it, a novel method of PANI/α-CD-coated stir bar sorptive extraction (SBSE) followed by high performance liquid chromatography-ultraviolet (HPLC-UV) detection was developed for the determination of trace PCBs in environmental waters. To obtain the best extraction performance for target PCBs, several parameters affecting SBSE, such as extraction time, stirring rate, and ionic strength were investigated. Under optimal experimental conditions, the limits of detection (LODs) of the proposed method for seven PCBs were in the range of 0.048-0.22 μg/L, and the RSDs were 5.3-9.8% (n=7, c=1 μg/L). Enrichment factors (EFs) ranging from 39.8 to 68.4-fold (theoretical EF, 83.3-fold) for target analytes were achieved. The proposed method was successfully applied for the determination of seven target PCBs in Yangtze River water and East Lake water, and the recoveries were in the range of 73.0-120% for the spiked East Lake water samples and 82.7-121% for the spiked Yangtze River water samples, respectively. Copyright © 2015 Elsevier B.V. All rights reserved.

Ultrasound-Guided Bar Edge Labeling in the Perioperative Assessment of Nuss Bar Removal.

PubMed

Incerti, Filippo; Bertocchini, Alessia; Ghionzoli, Marco; Messineo, Antonio

2017-12-01

Nuss bar removal after minimally invasive repair of pectus excavatum in patients where bar ends are not palpable, can be a challenging procedure for the surgeon; a blind dissection toward the bar edges may lead to intercostal vessels or deep intercostal muscle injuries. In this article, we describe a fast, repeatable, low-cost technique to detect bar edge and stabilizers. A perioperative scan is performed by means of a portable ultrasonograph a few minutes before the operation. The bar edge stabilizer is detected as a hyperechogenic image with a concentric crescent while the bar edge is detected as a hyperechogenic dashed line with net edges. The scan is performed, and the actual projection on the skin of the metal plaque bulk is then labeled on the patient's chest by an ink marker. We believe that this method may improve morbidity, operative time, and consequently, hospitalization length and costs.

Evaluation of a nontoxic rigid polymer as connecting bar in external skeletal fixators.

PubMed

Störk, Christoph K; Canivet, Philippe; Baidak, Alexandre A; Balligand, Marc H

2003-01-01

To investigate the mechanical characteristics of a nontoxic, low-cost, rigid polymer (RP) and to compare the structural and mechanical properties of a full-frame external skeletal fixator (ESF) with either RP connecting bars, polymethylmethacrylate (PMMA) connecting bars, or stainless-steel (SS) clamps and connecting bars. In vitro mechanical evaluation. Mechanical properties were assessed using an in vitro bone fracture model with a bilateral uniplanar ESF (type II). Identical ESF were built with connecting bars using RP (n = 8), PMMA (n = 8), and SS connecting bars and clamps (System Meynard; n = 3). Nondestructive mechanical tests were performed in uniaxial compression (AC) and craniocaudal (CC) 4-point bending, as well as fatigue AC. Composite stiffness for each specimen and for each loading mode was calculated from 6 replicate measures using the slope of the load displacement curve at small displacements. RP, PMMA, and SS ESF constructs yielded mean +/- SD composite stiffness values of 227 +/- 15, 381 +/- 30, and 394 +/- 9 N/mm in AC and of 35 +/- 2, 24 +/- 2, and 15 +/- 0 N/mm in CC, respectively. Structural and mechanical properties of RP are satisfactorily rigid and fatigue resistant for its use as a connecting bar in ESF. RP connecting bars in an ESF are a reliable, versatile, nontoxic and inexpensive option for the veterinary surgeon. Copyright 2003 by The American College of Veterinary Surgeons

Is Domain Highlighting Actually Helpful in Identifying Phishing Web Pages?

PubMed

Xiong, Aiping; Proctor, Robert W; Yang, Weining; Li, Ninghui

2017-06-01

To evaluate the effectiveness of domain highlighting in helping users identify whether Web pages are legitimate or spurious. As a component of the URL, a domain name can be overlooked. Consequently, browsers highlight the domain name to help users identify which Web site they are visiting. Nevertheless, few studies have assessed the effectiveness of domain highlighting, and the only formal study confounded highlighting with instructions to look at the address bar. We conducted two phishing detection experiments. Experiment 1 was run online: Participants judged the legitimacy of Web pages in two phases. In Phase 1, participants were to judge the legitimacy based on any information on the Web page, whereas in Phase 2, they were to focus on the address bar. Whether the domain was highlighted was also varied. Experiment 2 was conducted similarly but with participants in a laboratory setting, which allowed tracking of fixations. Participants differentiated the legitimate and fraudulent Web pages better than chance. There was some benefit of attending to the address bar, but domain highlighting did not provide effective protection against phishing attacks. Analysis of eye-gaze fixation measures was in agreement with the task performance, but heat-map results revealed that participants' visual attention was attracted by the highlighted domains. Failure to detect many fraudulent Web pages even when the domain was highlighted implies that users lacked knowledge of Web page security cues or how to use those cues. Potential applications include development of phishing prevention training incorporating domain highlighting with other methods to help users identify phishing Web pages.

Bar-spheroid interaction in galaxies

NASA Technical Reports Server (NTRS)

Hernquist, Lars; Weinberg, Martin D.

1992-01-01

N-body simulation and linear analysis is employed to investigate the secular evolution of barred galaxies, with emphasis on the interaction between bars and spheroidal components of galaxies. This interaction is argued to drive secular transfer of angular momentum from bars to spheroids, primarily through resonant coupling. A moderately strong bar, having mass within corotation about 0.3 times the enclosed spheroid mass, is predicted to shed all its angular momentum typically in less than about 10 exp 9 yr. Even shorter depletion time scales are found for relatively more massive bars. It is suggested either that spheroids around barred galaxies are structured so as to inhibit strong coupling with bars, or that bars can form by unknown processes long after disks are established. The present models reinforce the notion that bars can drive secular evolution in galaxies.

High Bar Swing Performance in Novice Adults: Effects of Practice and Talent

ERIC Educational Resources Information Center

Busquets, Albert; Marina, Michel; Irurtia, Alfredo; Ranz, Daniel; Angulo-Barroso, Rosa M.

2011-01-01

An individual's a priori talent can affect movement performance during learning. Also, task requirements and motor-perceptual factors are critical to the learning process. This study describes changes in high bar swing performance after a 2-month practice period. Twenty-five novice participants were divided by a priori talent level…

Implant-retained mandibular bar-supported overlay dentures: a finite element stress analysis of four different bar heights.

PubMed

Rismanchian, Mansoor; Dakhilalian, Mansour; Bajoghli, Farshad; Ghasemi, Ehsan; Sadr-Eshkevari, Pooyan

2012-04-01

Proper stress distribution on dental implants is necessary in bar-retained implant overlay dentures. We aimed to comparatively assess this stress distribution according to different bar heights using finite element models. A three-dimensional (3D) computer model of mandible with 2 implants (ITI, 4.1 mm diameter and 12 mm length) in canine areas and an overlying implant-supported bar-retained overlay denture were simulated with 0-, 1-, 2-, and 3-mm bar heights using ABAQUS software. A vertical force was applied to the left first molar and gradually increased from 0 to 50 N. The resultant stress distribution was evaluated. Bars of 1 and 2 mm in height transferred the least stress to the implants (3.882 and 3.896 MPa, respectively). The 0-mm height of the bar connection transferred the highest stress value (4.277 MPa). The amount of stress transferred by 3-mm heights of the bar connection was greater than that of 1- and 2-mm bar connections and smaller than that of 0-mm bar connection (4.165 kgN). This 3D finite element analysis study suggested that the use of Dolder bar attachment with 1- and 2-mm heights could be associated with appropriate stress distribution for implant-retained overlay dentures.

Work domain constraints for modelling surgical performance.

PubMed

Morineau, Thierry; Riffaud, Laurent; Morandi, Xavier; Villain, Jonathan; Jannin, Pierre

2015-10-01

Three main approaches can be identified for modelling surgical performance: a competency-based approach, a task-based approach, both largely explored in the literature, and a less known work domain-based approach. The work domain-based approach first describes the work domain properties that constrain the agent's actions and shape the performance. This paper presents a work domain-based approach for modelling performance during cervical spine surgery, based on the idea that anatomical structures delineate the surgical performance. This model was evaluated through an analysis of junior and senior surgeons' actions. Twenty-four cervical spine surgeries performed by two junior and two senior surgeons were recorded in real time by an expert surgeon. According to a work domain-based model describing an optimal progression through anatomical structures, the degree of adjustment of each surgical procedure to a statistical polynomial function was assessed. Each surgical procedure showed a significant suitability with the model and regression coefficient values around 0.9. However, the surgeries performed by senior surgeons fitted this model significantly better than those performed by junior surgeons. Analysis of the relative frequencies of actions on anatomical structures showed that some specific anatomical structures discriminate senior from junior performances. The work domain-based modelling approach can provide an overall statistical indicator of surgical performance, but in particular, it can highlight specific points of interest among anatomical structures that the surgeons dwelled on according to their level of expertise.

Dowel bar retrofit performance in Wisconsin.

DOT National Transportation Integrated Search

2010-05-01

In 1999, WisDOT constructed test sections on I-39 to evaluate the dowel bar retrofit (DBR) rehabilitation technique for faulted concrete pavement slabs. Two years later, mortar deterioration and debonding were noted in the dowel slots. In response to...

Experimental study of the seismic performance of L-shaped columns with 500 MPa steel bars.

PubMed

Wang, Tiecheng; Liu, Xiao; Zhao, Hailong

2014-01-01

Based on tests on six L-shaped RC columns with 500 MPa steel bars, the effect of axial compression ratios and stirrup spacing on failure mode, bearing capacity, displacement, and curvature ductility of the specimens is investigated. Test results show that specimens with lower axial load and large stirrup characteristic value (larger than about 0.35) are better at ductility and seismic performance, while specimens under high axial load or with a small stirrup characteristic value (less than about 0.35) are poorer at ductility; L-shaped columns with 500 MPa steel bars show better bearing capacity and ductility in comparison with specimens with HRB400 steel bars.

Enhancement of surface migration by Mg doping in the metalorganic vapor phase epitaxy of N-polar (000\\bar{1}) GaN/sapphire

NASA Astrophysics Data System (ADS)

Tanikawa, Tomoyuki; Shojiki, Kanako; Aisaka, Takashi; Kimura, Takeshi; Kuboya, Shigeyuki; Hanada, Takashi; Katayama, Ryuji; Matsuoka, Takashi

2014-01-01

With respect to N-polar (000\\bar{1}) GaN grown on a sapphire substrate, the effects of Mg doping on the surface morphology, and the optical, and electrical properties are precisely investigated. By doping Mg, hillocks observed on the surface of (000\\bar{1}) GaN can be suppressed, while step bunching becomes severe. The atomic terrace width is extended with increasing Mg/Ga precursor ratio. Mg doping can promote the surface migration of Ga adatoms on a GaN surface during growth. In the case of heavily Mg-doped GaN, atomic steps become wavy. From photoluminescence spectra, the dominant transition was found to change from near-band-edge transition to donor-acceptor-pair transition. Hall-effect measurement shows p-type conduction at room temperature for a sample grown with the Mg/Ga precursor ratio of 4.5 × 10-3. The activation energy is 143 meV, which is comparable to that of Mg in the conventional Ga-polar (0001) GaN.

Acceptance of Nordic snack bars in children aged 8-11 years.

PubMed

Holmer, Anna; Hausner, Helene; Reinbach, Helene C; Bredie, Wender L P; Wendin, Karin

2012-01-01

A health promoting diet is suggested to be tailored to regional circumstances to preserve the cultural diversity in eating habits, as well as contribute to more environmentally friendly eating. It may influence consumer acceptance, however, if the components of the diet differs considerably from their habitual food. This study aimed to investigate whether snack bars composed of Nordic ingredients were accepted by 8-11 year-old Danish (n=134) and Swedish (n=109) children. A seven-point hedonic scale was used to measure the children's acceptance of five snack bars that varied in their composition of whole grains, berries and nuts. A preference rank ordering of the five bars was also performed. The results showed that samples that were rated highest in liking and were most preferred in both countries were a kamut/pumpkin bar and an oat/cranberry bar. The sample with the lowest rating that was also least preferred was a pumpernickel/sea buckthorn bar. Flavour was the most important determinant of overall liking followed by texture, odour and appearance. Children's acceptances and preferences were highly influenced by the sensory characteristics of the bars, mainly flavour. In agreement with earlier studies, the novel food ingredients seemed to influence children's preferences. The Nordic snack bars may have a potential to be a snack option for Danish and Swedish school children, but repeated exposures to the products are recommended to increase children's acceptance.

Solubility of carbon monoxide in n-hexane between 293 and 473 K and CO pressures up to 200 bar

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koelliker, R.; Thies, H.

The solubility of carbon monoxide, CO, in n-hexane was measured at 293, 323, 373, 423, and 473 K for CO partial pressures up to 200 bar. The enthalpy of solution was calculated between 293 and 473 K. Using the Krichevsky-Ilinskaya equation of state, the solubility of CO in n-hexane can be calculated between 293 and 423 K for CO partial pressures up to 200 bar with an accuracy better than 5%.

Glass Fiber Reinforced Polymer Dowel Bar Evaluation

DOT National Transportation Integrated Search

2012-09-01

Glass Fiber Reinforced Polymer (GFRP) dowel bars were installed on one new construction project and two dowel bar : retrofit projects to evaluate the performance of this type of dowel bar in comparison to steel dowel bars installed on the same : cont...

Bar dimensions and bar shapes in estuaries

NASA Astrophysics Data System (ADS)

Leuven, Jasper; Kleinhans, Maarten; Weisscher, Steven; van der Vegt, Maarten

2016-04-01

Estuaries cause fascinating patterns of dynamic channels and shoals. Intertidal sandbars are valuable habitats, whilst channels provide access to harbors. We still lack a full explanation and classification scheme for the shapes and dimensions of bar patterns in natural estuaries, in contrast with bars in rivers. Analytical physics-based models suggest that bar length in estuaries increases with flow velocity, tidal excursion length or estuary width, depending on which model. However, these hypotheses were never validated for lack of data and experiments. We present a large dataset and determine the controls on bar shape and dimensions in estuaries, spanning bar lengths from centimeters (experiments) to 10s of kilometers length. First, we visually identified and classified 190 bars, measured their dimensions (width, length, height) and local braiding index. Data on estuarine geometry and tidal characteristics were obtained from governmental databases and literature on case studies. We found that many complex bars can be seen as simple elongated bars partly cut by mutually evasive ebb- and flood-dominated channels. Data analysis shows that bar dimensions scale with estuary dimensions, in particular estuary width. Breaking up the complex bars in simple bars greatly reduced scatter. Analytical bar theory overpredicts bar dimensions by an order of magnitude in case of small estuarine systems. Likewise, braiding index depends on local width-to-depth ratio, as was previously found for river systems. Our results suggest that estuary dimensions determine the order of magnitude of bar dimensions, while tidal characteristics modify this. We will continue to model bars numerically and experimentally. Our dataset on tidal bars enables future studies on the sedimentary architecture of geologically complex tidal deposits and enables studying effects of man-induced perturbations such as dredging and dumping on bar and channel patterns and habitats.

Polydimethylsiloxane/covalent triazine frameworks coated stir bar sorptive extraction coupled with high performance liquid chromatography-ultraviolet detection for the determination of phenols in environmental water samples.

PubMed

Zhong, Cheng; He, Man; Liao, Huaping; Chen, Beibei; Wang, Cheng; Hu, Bin

2016-04-08

In this work, covalent triazine frameworks (CTFs) were introduced in stir bar sorptive extraction (SBSE) and a novel polydimethylsiloxane(PDMS)/CTFs stir bar coating was prepared by sol-gel technique for the sorptive extraction of eight phenols (including phenol, 2-chlorophenol, 2-nitrophenol, 4-nitrophenol, 2,4-dimethylphenol, p-chloro-m-cresol and 2,4-dichlorophenol, 2,4,6-trichlorophenol) from environmental water samples followed by high performance liquid chromatography-ultraviolet (HPLC-UV) detection. The prepared PDMS/CTFs coated stir bar showed good preparation reproducibility with the relative standard deviations (RSDs) ranging from 3.5 to 5.7% (n=7) in one batch, and from 3.7 to 9.3% (n=7) among different batches. Several parameters affecting SBSE of eight target phenols including extraction time, stirring rate, sample pH, ionic strength, desorption solvent and desorption time were investigated. Under the optimal experimental conditions, the limits of detection (LODs, S/N=3) were found to be in the range of 0.08-0.30 μg/L. The linear range was 0.25-500 μg/L for 2-nitrophenol, 0.5-500 μg/L for phenol, 2-chlorophenol, 4-nitrophenol as well as 2,4-dimethylphenol, and 1-500 μg/L for p-chloro-m-cresol, 2,4-dichlorophenol as well as 2,4,6-trichlorophenol, respectively. The intra-day relative standard deviations (RSDs) were in the range of 4.3-9.4% (n=7, c=2 μg/L) and the enrichment factors ranged from 64.9 to 145.6 fold (theoretical enrichment factor was 200-fold). Compared with commercial PDMS coated stir bar (Gerstel) and PEG coated stir bar (Gerstel), the prepared PDMS/CTFs stir bar showed better extraction efficiency for target phenol compounds. The proposed method was successfully applied to the analysis of phenols in environmental water samples and good relative recoveries were obtained with the spiking level at 2, 10, 50 μg/L, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

A Modern Picture of Barred Galaxy Dynamics

NASA Astrophysics Data System (ADS)

Petersen, Michael; Weinberg, Martin; Katz, Neal

2018-01-01

Observations of disk galaxies suggest that bars are responsible for altering global galaxy parameters (e.g. structures, gas fraction, star formation rate). The canonical understanding of the mechanisms underpinning bar-driven secular dynamics in disk galaxies has been largely built upon the analysis of linear theory, despite galactic bars being clearly demonstrated to be nonlinear phenomena in n-body simulations. We present simulations of barred Milky Way-like galaxy models designed to elucidate nonlinear barred galaxy dynamics. We have developed two new methodologies for analyzing n-body simulations that give the best of both powerful analytic linear theory and brute force simulation analysis: orbit family identification and multicomponent torque analysis. The software will be offered publicly to the community for their own simulation analysis.The orbit classifier reveals that the details of kinematic components in galactic disks (e.g. the bar, bulge, thin disk, and thick disk components) are powerful discriminators of evolutionary paradigms (i.e. violent instabilities and secular evolution) as well as the basic parameters of the dark matter halo (mass distribution, angular momentum distribution). Multicomponent torque analysis provides a thorough accounting of the transfer of angular momentum between orbits, global patterns, and distinct components in order to better explain the underlying physics which govern the secular evolution of barred disk galaxies.Using these methodologies, we are able to identify the successes and failures of linear theory and traditional n-body simulations en route to a detailed understanding of the control bars exhibit over secular evolution in galaxies. We present explanations for observed physical and velocity structures in observations of barred galaxies alongside predictions for how structures will vary with dynamical properties from galaxy to galaxy as well as over the lifetime of a galaxy, finding that the transfer of angular

Preparation, characterization and application of a new stir bar sorptive extraction based on poly(vinylphthalimide-co-N,N'-methylenebisacrylamide) monolith.

PubMed

Huang, Xiaojia; Chen, Linli; Yuan, Dongxing; Luo, Xianbin

2011-12-01

In this study, a new stir bar sorptive extraction (SBSE) coating based on poly(vinylphthalimide-co-N,N'-methylenebisacrylamide) monolith (SBSE-VPMB) was prepared. The influences of the contents of monomer in polymerization mixture and the percentage of porogen solvent on the extraction performance were investigated thoroughly. Several characteristic techniques, such as elemental analysis, scanning electron microscopy, mercury intrusion porosimetry and infrared spectroscopy, were used to characterize the monolithic material. The analysis of oxfendazole (OFZ) and mebendazole (MBZ) in milk and honey samples by the combination of SBSE with HPLC with diode array detection was selected as paradigms for the practical evaluation of the new coating. Under the optimized extraction conditions, the limits of detection (S/N=3) for OFZ and MBZ were 0.23-0.60 μg/L in milk and 0.24-1.08 μg/L in honey, respectively. The method also showed good linearity, repeatability, high feasibility and acceptable recoveries for real samples. At the same time, the extraction performance and the distribution coefficients (K(VPMB/W)) of OFZ and MBZ on SBSE-VPMB were compared with other SBSEs based on porous monoliths and commercial SBSE. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Experimental Study of the Seismic Performance of L-Shaped Columns with 500 MPa Steel Bars

PubMed Central

Wang, Tiecheng; Liu, Xiao; Zhao, Hailong

2014-01-01

Based on tests on six L-shaped RC columns with 500 MPa steel bars, the effect of axial compression ratios and stirrup spacing on failure mode, bearing capacity, displacement, and curvature ductility of the specimens is investigated. Test results show that specimens with lower axial load and large stirrup characteristic value (larger than about 0.35) are better at ductility and seismic performance, while specimens under high axial load or with a small stirrup characteristic value (less than about 0.35) are poorer at ductility; L-shaped columns with 500 MPa steel bars show better bearing capacity and ductility in comparison with specimens with HRB400 steel bars. PMID:24967420

The N Domain of Human Angiotensin-I-converting Enzyme

PubMed Central

Anthony, Colin S.; Corradi, Hazel R.; Schwager, Sylva L. U.; Redelinghuys, Pierre; Georgiadis, Dimitris; Dive, Vincent; Acharya, K. Ravi; Sturrock, Edward D.

2010-01-01

Angiotensin-I-converting enzyme (ACE) plays a critical role in the regulation of blood pressure through its central role in the renin-angiotensin and kallikrein-kinin systems. ACE contains two domains, the N and C domains, both of which are heavily glycosylated. Structural studies of ACE have been fraught with severe difficulties because of surface glycosylation of the protein. In order to investigate the role of glycosylation in the N domain and to create suitable forms for crystallization, we have investigated the importance of the 10 potential N-linked glycan sites using enzymatic deglycosylation, limited proteolysis, and mass spectrometry. A number of glycosylation mutants were generated via site-directed mutagenesis, expressed in CHO cells, and analyzed for enzymatic activity and thermal stability. At least eight of 10 of the potential glycan sites are glycosylated; three C-terminal sites were sufficient for expression of active N domain, whereas two N-terminal sites are important for its thermal stability. The minimally glycosylated Ndom389 construct was highly suitable for crystallization studies. The structure in the presence of an N domain-selective phosphinic inhibitor RXP407 was determined to 2.0 Å resolution. The Ndom389 structure revealed a hinge region that may contribute to the breathing motion proposed for substrate binding. PMID:20826823

Evaluation of longitudinal joint tie bar system.

DOT National Transportation Integrated Search

2011-09-01

"An adequate longitudinal joint tie bar system is essential in the overall performance of concrete pavement. Excessive : longitudinal joint openings are believed to be caused by either inadequate tie bar size or spacing or improper tie bar : installa...

Dynamic working memory performance in individuals with single-domain amnestic mild cognitive impairment.

PubMed

Guild, Emma B; Vasquez, Brandon P; Maione, Andrea M; Mah, Linda; Ween, Jon; Anderson, Nicole D

2014-01-01

Previous studies have observed poorer working memory performance in individuals with amnestic mild cognitive impairment than in healthy older adults. It is unclear, however, whether these difficulties are true only of the multiple-domain clinical subtype in whom poorer executive functioning is common. The current study examined working memory, as measured by the self-ordered pointing task (SOPT) and an n-back task, in healthy older adults and adults with single-domain amnestic mild cognitive impairment (aMCI). Individuals with single-domain aMCI committed more errors and required longer to develop an organizational strategy on the SOPT. The single-domain aMCI group did not differ from healthy older adults on the 1-back or 2-back, but had poorer discrimination on the 3-back task. This is, to our knowledge, the first characterization of dynamic working memory performance in a single-domain aMCI group. These results lend support for the idea that clinical amnestic MCI subtypes may reflect different stages on a continuum of progression to dementia and question whether standardized measures of working memory (span tasks) are sensitive enough to capture subtle changes in performance.

Simulation of the oscillation regimes of bowed bars: a non-linear modal approach

NASA Astrophysics Data System (ADS)

Inácio, Octávio; Henrique, Luís.; Antunes, José

2003-06-01

It is still a challenge to properly simulate the complex stick-slip behavior of multi-degree-of-freedom systems. In the present paper we investigate the self-excited non-linear responses of bowed bars, using a time-domain modal approach, coupled with an explicit model for the frictional forces, which is able to emulate stick-slip behavior. This computational approach can provide very detailed simulations and is well suited to deal with systems presenting a dispersive behavior. The effects of the bar supporting fixture are included in the model, as well as a velocity-dependent friction coefficient. We present the results of numerical simulations, for representative ranges of the bowing velocity and normal force. Computations have been performed for constant-section aluminum bars, as well as for real vibraphone bars, which display a central undercutting, intended to help tuning the first modes. Our results show limiting values for the normal force FN and bowing velocity ẏbow for which the "musical" self-sustained solutions exist. Beyond this "playability space", double period and even chaotic regimes were found for specific ranges of the input parameters FN and ẏbow. As also displayed by bowed strings, the vibration amplitudes of bowed bars also increase with the bow velocity. However, in contrast to string instruments, bowed bars "slip" during most of the motion cycle. Another important difference is that, in bowed bars, the self-excited motions are dominated by the system's first mode. Our numerical results are qualitatively supported by preliminary experimental results.

Print media coverage of California's smokefree bar law

PubMed Central

Magzamen, S.; Charlesworth, A.; Glantz, S.

2001-01-01

OBJECTIVE—To assess the print media coverage of California's smokefree bar law in the state of California.
DESIGN—Content analysis of newspaper, trade journal, and magazine items.
SUBJECTS—Items regarding the smokefree bar law published seven months before and one year following the implementation of the smokefree bar law (June 1997 to December 1998). Items consisted of news articles (n = 446), opinion editorials (n = 31), editorials (n = 104), letters to the editor (n = 240), and cartoons (n = 10).
MAIN OUTCOME MEASURES—Number and timing of publication of items, presence of tobacco industry arguments or public health arguments regarding law, positive, negative, and neutral views of opinion items published.
RESULTS—53% of items published concerning the smokefree bar law were news articles, 47% were opinion items. 45% of items regarding the smokefree bar law were published during the first month of implementation. The tobacco industry dominated coverage in most categories (economics, choice, enforcement, ventilation, legislation, individual quotes), except for categories public health used the most frequently (government role, tactics, organisational quotes). Anti-law editorials and letters to the editor were published more than pro-law editorials and letters. Region of the state, paper size, presence of local clean indoor air legislation, and voting on tobacco related ballot initiatives did not have an impact on the presence of opinion items.
CONCLUSIONS—The tobacco industry succeeded in obtaining more coverage of the smokefree bar law, both in news items and opinion items. The tobacco industry used historical arguments of restricting freedom of choice and economic ramifications in fighting the smokefree bar law, while public health groups focused on the worker protection issue, and exposed tobacco industry tactics. Despite the skewed coverage, public health groups obtained adequate attention to their arguments to keep the law in

Structural and functional properties of the N transcriptional activation domain of thyroid transcription factor-1: similarities with the acidic activation domains.

PubMed Central

Tell, G; Perrone, L; Fabbro, D; Pellizzari, L; Pucillo, C; De Felice, M; Acquaviva, R; Formisano, S; Damante, G

1998-01-01

The thyroid transcription factor 1 (TTF-1) is a tissue-specific transcription factor involved in the development of thyroid and lung. TTF-1 contains two transcriptional activation domains (N and C domain). The primary amino acid sequence of the N domain does not show any typical characteristic of known transcriptional activation domains. In aqueous solution the N domain exists in a random-coil conformation. The increase of the milieu hydrophobicity, by the addition of trifluoroethanol, induces a considerable gain of alpha-helical structure. Acidic transcriptional activation domains are largely unstructured in solution, but, under hydrophobic conditions, folding into alpha-helices or beta-strands can be induced. Therefore our data indicate that the inducibility of alpha-helix by hydrophobic conditions is a property not restricted to acidic domains. Co-transfections experiments indicate that the acidic domain of herpes simplex virus protein VP16 (VP16) and the TTF-1 N domain are interchangeable and that a chimaeric protein, which combines VP16 linked to the DNA-binding domain of TTF-1, undergoes the same regulatory constraints that operate for the wild-type TTF-1. In addition, we demonstrate that the TTF-1 N domain possesses two typical properties of acidic activation domains: TBP (TATA-binding protein) binding and ability to activate transcription in yeast. Accordingly, the TTF-1 N domain is able to squelch the activity of the p65 acidic domain. Altogether, these structural and functional data suggest that a non-acidic transcriptional activation domain (TTF-1 N domain) activates transcription by using molecular mechanisms similar to those used by acidic domains. TTF-1 N domain and acidic domains define a family of proteins whose common property is to activate transcription through the use of mechanisms largely conserved during evolutionary development. PMID:9425125

BAR Proteins PSTPIP1/2 Regulate Podosome Dynamics and the Resorption Activity of Osteoclasts

PubMed Central

Sztacho, Martin; Segeletz, Sandra; Sanchez-Fernandez, Maria Arantzazu; Czupalla, Cornelia; Niehage, Christian; Hoflack, Bernard

2016-01-01

Bone resorption in vertebrates relies on the ability of osteoclasts to assemble F-actin-rich podosomes that condense into podosomal belts, forming sealing zones. Sealing zones segregate bone-facing ruffled membranes from other membrane domains, and disassemble when osteoclasts migrate to new areas. How podosome/sealing zone dynamics is regulated remains unknown. We illustrate the essential role of the membrane scaffolding F-BAR-Proline-Serine-Threonine Phosphatase Interacting Proteins (PSTPIP) 1 and 2 in this process. Whereas PSTPIP2 regulates podosome assembly, PSTPIP1 regulates their disassembly. PSTPIP1 recruits, through its F-BAR domain, the protein tyrosine phosphatase non-receptor type 6 (PTPN6) that de-phosphophorylates the phosphatidylinositol 5-phosphatases SHIP1/2 bound to the SH3 domain of PSTPIP1. Depletion of any component of this complex prevents sealing zone disassembly and increases osteoclast activity. Thus, our results illustrate the importance of BAR domain proteins in podosome structure and dynamics, and identify a new PSTPIP1/PTPN6/SHIP1/2-dependent negative feedback mechanism that counterbalances Src and PI(3,4,5)P3 signalling to control osteoclast cell polarity and activity during bone resorption. PMID:27760174

Sorptive extraction using polydimethylsiloxane/metal-organic framework coated stir bars coupled with high performance liquid chromatography-fluorescence detection for the determination of polycyclic aromatic hydrocarbons in environmental water samples.

PubMed

Hu, Cong; He, Man; Chen, Beibei; Zhong, Cheng; Hu, Bin

2014-08-22

In this work, metal-organic frameworks (MOFs, Al-MIL-53-NH₂) were synthesized via the hydrothermal method, and novel polydimethylsiloxane/metal-organic framework (PDMS/MOFs, PDMS/Al-MIL-53-NH₂)-coated stir bars were prepared by the sol-gel technique. The preparation reproducibility of the PDMS/MOFs-coated stir bar was good, with relative standard deviations (RSDs) ranging from 4.8% to 14.9% (n=7) within one batch and from 6.2% to 16.9% (n=6) among different batches. Based on this fact, a new method of PDMS/MOFs-coated stir bar sorptive extraction (SBSE) and ultrasonic-assisted liquid desorption (UALD) coupled with high performance liquid chromatography-fluorescence detection (HPLC-FLD) was developed for the determination of polycyclic aromatic hydrocarbons (PAHs) in environmental water samples. To obtain the best extraction performance for PAHs, several parameters affecting SBSE, such as extraction time, stirring rate, and extraction temperature, were investigated. Under optimal experimental conditions, wide linear ranges and good RSDs (n=7) were obtained. With enrichment factors (EFs) of 16.1- to 88.9-fold (theoretical EF, 142-fold), the limits of detection (LODs, S/N=3) of the developed method for the target PAHs were found to be in the range of 0.05-2.94 ng/L. The developed method was successfully applied to the analysis of PAHs in Yangtze River and East Lake water samples. Copyright © 2014 Elsevier B.V. All rights reserved.

[Amaranth bars enriched with fructans: acceptability and nutritional value].

PubMed

Dias Capriles, Vanessa; Gomes Arêas, José Alfredo

2010-09-01

There is an increasing appeal for convenience foods with potential health benefits to the consumer. Raw materials with high nutritional value and functional properties must be used on the development of these food products. Amaranth is a gluten-free grain with high nutrition value. Inulin and oligofructose are prebiotic ingredients presenting effects as the enhancement of calcium absorption. Amaranth bars enriched with inulin and oligofructose were developed in the flavors: banana, Brazilian nuts and dried grape, coconut, peach, strawberry and wall nut. The proximate composition were determined and compared to commercial cereal bars, available in traditional (n=59), light (n=60), diet (n=8), with soy (n=10) and quinoa (n=1) categories. Amaranth bars present mean global acceptance values from 6.3 to 7.6 on a 9-point hedonic scale, nutritional advantages as compared to commercial cereal bars (caloric reduction and higher levels of dietary fiber). Although amaranth is an unknown raw material in Brazil, it shows good potential to be used in the manufacturing of ready-to-eat products. As they are gluten free, these amaranth bars are also an alternative product for celiacs, also contributing to the enhancement of calcium absorption, a problem frequently observed in these patients.

Structure and evolution of N-domains in AAA metalloproteases.

PubMed

Scharfenberg, Franka; Serek-Heuberger, Justyna; Coles, Murray; Hartmann, Marcus D; Habeck, Michael; Martin, Jörg; Lupas, Andrei N; Alva, Vikram

2015-02-27

Metalloproteases of the AAA (ATPases associated with various cellular activities) family play a crucial role in protein quality control within the cytoplasmic membrane of bacteria and the inner membrane of eukaryotic organelles. These membrane-anchored hexameric enzymes are composed of an N-terminal domain with one or two transmembrane helices, a central AAA ATPase module, and a C-terminal Zn(2+)-dependent protease. While the latter two domains have been well studied, so far, little is known about the N-terminal regions. Here, in an extensive bioinformatic and structural analysis, we identified three major, non-homologous groups of N-domains in AAA metalloproteases. By far, the largest one is the FtsH-like group of bacteria and eukaryotic organelles. The other two groups are specific to Yme1: one found in plants, fungi, and basal metazoans and the other one found exclusively in animals. Using NMR and crystallography, we determined the subunit structure and hexameric assembly of Escherichia coli FtsH-N, exhibiting an unusual α+β fold, and the conserved part of fungal Yme1-N from Saccharomyces cerevisiae, revealing a tetratricopeptide repeat fold. Our bioinformatic analysis showed that, uniquely among these proteins, the N-domain of Yme1 from the cnidarian Hydra vulgaris contains both the tetratricopeptide repeat region seen in basal metazoans and a region of homology to the N-domains of animals. Thus, it is a modern-day representative of an intermediate in the evolution of animal Yme1 from basal eukaryotic precursors. Copyright © 2015. Published by Elsevier Ltd.

Polarization effects in the N-bar+N{yields}{pi}+l{sup +}+l{sup -} reaction: General analysis and numerical estimations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gakh, G. I.; Rekalo, A. P.; Tomasi-Gustafsson, E.

2011-02-15

A general formalism is developed to calculate the cross section and the polarization observables for the reaction N-bar+N{yields}{pi}+l{sup +}+l{sup -}. The matrix element and the observables are expressed in terms of six scalar amplitudes (complex functions of three kinematical variables) that determine the reaction dynamics. The numerical predictions are given in the frame of a particular model in the kinematical range accessible in the antiproton annihilation at Darmstadt (PANDA) experiment at the Facility for Antiproton and Ion Research (FAIR).

Analysis of preservatives with different polarities in beverage samples by dual-phase dual stir bar sorptive extraction combined with high-performance liquid chromatography.

PubMed

Xu, Jin; Chen, Beibei; He, Man; Hu, Bin

2013-02-22

A new concept of "dual-phase dual stir bar sorptive extraction (SBSE)" was proposed to simultaneously extract six preservatives with different polarities (logKo/w values of 1.27-3.41), namely, benzoic acid (BA), sorbic acid (SA), methyl p-hydroxybenzoate (MP), ethyl p-hydroxybenzoate (EP), propyl p-hydroxybenzoate (PP), and butyl p-hydroxybenzoate (BP). The dual-phase dual SBSE apparatus was consisted of two differently coated stir bars, a 3-aminopropyltriethoxysilane (APTES)-hydroxy-terminated silicone oil (OH-TSO)-coated stir bar that was prepared by sol-gel technique and a C(18) silica (C(18))-polydimethylsiloxane (PDMS)-coated stir bar that was prepared by adhesion. In dual-phase dual SBSE, the two stir bars with different coatings were placed in the same sample solution for the simultaneous extraction of the target analytes with different polarities, and then the bars were desorbed in the same desorption solvent. The extraction performance of the dual-phase dual SBSE for the six preservatives was evaluated by comparing with the conventional SBSE (individual stir bar) with different coatings, including commercial PDMS, homemade PDMS, C(18)-APTES-OH-TSO, APTES-OH-TSO, and C(18)-PDMS. The experimental results showed that the dual-phase dual SBSE had the highest extraction efficiency for the six target preservatives. Based on this fact, a novel method by combining the dual-phase dual SBSE which was consisted of the APTES-OH-TSO-coated and C(18)-PDMS-coated stir bars with high-performance liquid chromatography-ultraviolet detection (HPLC-UV) was developed for the simultaneous analysis of six target beverage preservatives in beverages. Under optimal conditions, the limits of detection (LODs) for six target preservatives ranged from 0.6 to 2.7 μgL(-1) with the relative standard deviations (RSDs) of 4.6-9.2% (C(BA,SA)=5 μgL(-1),C(MP)=20 μgL(-1),C(EP,PP,BP)=10 μgL(-1), n=7). The enrichment factors (EFs) were approximately 16-42-fold (theoretical EF was 50-fold

A psychology of liberation for Central America: the unfinished work of Ignacio Martín-Baró (1942-1989).

PubMed

Gondra, José María

2013-01-01

On November 16, 1989 the world was shocked by the news of the assassination of six Jesuits at the campus of the Universidad Centro Americana José Simeón Cañas (UCA) in San Salvador, El Salvador. Among those murdered by government soldiers was Ignacio Martín-Baró, a PhD in social psychology from the University of Chicago who at that time was the Vice-Rector for Academic Affairs and Vice-President of the Interamerican Society of Psychology (SIP). Drawing on Martín-Baró's published writings and non-published academic papers and correspondence, this article traces the evolution of the Spanish-born Jesuit who became a leading authority among Latin American social psychologists. In particular, it analyzes his project of becoming a clinical psychologist under the influence of psychoanalysis, his critical social psychology aimed to "de-ideologize" the oppressed social classes of El Salvador, and his ultimate project of a psychology of liberation for Latin America. Martín-Baró's work came to a tragic end just when it began to bear fruit, but it stands as a testimony to a lifetime committed to the human values of democracy, social justice and service to society's poorest and most neglected.

Search for CP Violation in Hyperon Decay: $$\\Xi^- / \\bar{\\Xi}^+$$ and $$\\Lambda / \\bar{\\Lambda}$$ (in French)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leros, Nicolas

2001-06-01

The HyperCP(EB71) experiment, performed at the Fermi National Accelerator Laboratory in the United States, provides a primary search for direct OP violation in the decays ofmore » $$\\Xi^-/\\bar{\\Xi}^+$$ and $$\\Lambda/ \\bar{\\Lambda}$$ hyperons....« less

Magnetic domain configuration of (111)-oriented LaFeO 3 epitaxial thin films

DOE PAGES

Hallsteinsen, I.; Moreau, M.; Chopdekar, R. V.; ...

2017-08-22

In antiferromagnetic spintronics control of the domains and corresponding spin axis orientation is crucial for devices. Here we investigate the antiferromagnetic axis in (111)-oriented LaFeO 3 SrTiO 3 , which is coupled to structural twin domains. The structural domains have either the orthorhombic a- or b-axis along the in-plane <1more » $$\\bar{1}$$0> cubic directions of the substrate, and the corresponding magnetic domains have the antiferromagnetic axis in the sample plane. Six degenerate antiferromagnetic axes are found corresponding to the <1$$\\bar{1}$$0> and <11$$\\bar{2}$$> in-plane directions. This is in contrast to the biaxial anisotropy in (001)-oriented films and reflects how crystal orientation can be used to control magnetic anisotropy in antiferromagnets.« less

Impact of Partial and Comprehensive Smoke-Free Regulations on Indoor Air Quality in Bars

PubMed Central

Kim, Jeonghoon; Ban, Hyunkyung; Hwang, Yunhyung; Ha, Kwonchul; Lee, Kiyoung

2016-01-01

In Korea, smoke-free regulations have been gradually implemented in bars based on venue size. Smoking bans were implemented in 2013 for bars ≥150 m2, in 2014 for bars ≥100 m2, and in 2015 for bars of all sizes. The purpose of this study was to determine indoor fine particle (PM2.5) concentrations in bars before and after implementation of the smoke-free policies based on venue size. Indoor PM2.5 concentrations were measured with real-time aerosol monitors at four time points: (1) pre-regulation (n = 75); (2) after implementing the ban in bars ≥150 m2 (n = 75); (3) after implementing the ban in bars ≥100 m2 (n = 107); and (4) when all bars were smoke-free (n = 79). Our results showed that the geometric mean of the indoor PM2.5 concentrations of all bars decreased from 98.4 μg/m3 pre-regulation to 79.5, 42.9, and 26.6 μg/m3 after the ban on smoking in bars ≥150 m2, ≥100 m2, and all bars, respectively. Indoor PM2.5 concentrations in bars of each size decreased only after the corresponding regulations were implemented. Although smoking was not observed in Seoul bars after smoking was banned in all bars, smoking was observed in 4 of 21 bars in Changwon. Our study concludes that the greatest decrease in PM2.5 concentrations in bars was observed after the regulation covering all bars was implemented. However, despite the comprehensive ban, smoking was observed in bars in Changwon. Strict compliance with the regulations is needed to improve indoor air quality further. PMID:27472349

Impact of Partial and Comprehensive Smoke-Free Regulations on Indoor Air Quality in Bars.

PubMed

Kim, Jeonghoon; Ban, Hyunkyung; Hwang, Yunhyung; Ha, Kwonchul; Lee, Kiyoung

2016-07-26

In Korea, smoke-free regulations have been gradually implemented in bars based on venue size. Smoking bans were implemented in 2013 for bars ≥150 m², in 2014 for bars ≥100 m², and in 2015 for bars of all sizes. The purpose of this study was to determine indoor fine particle (PM2.5) concentrations in bars before and after implementation of the smoke-free policies based on venue size. Indoor PM2.5 concentrations were measured with real-time aerosol monitors at four time points: (1) pre-regulation (n = 75); (2) after implementing the ban in bars ≥150 m² (n = 75); (3) after implementing the ban in bars ≥100 m² (n = 107); and (4) when all bars were smoke-free (n = 79). Our results showed that the geometric mean of the indoor PM2.5 concentrations of all bars decreased from 98.4 μg/m³ pre-regulation to 79.5, 42.9, and 26.6 μg/m³ after the ban on smoking in bars ≥150 m², ≥100 m², and all bars, respectively. Indoor PM2.5 concentrations in bars of each size decreased only after the corresponding regulations were implemented. Although smoking was not observed in Seoul bars after smoking was banned in all bars, smoking was observed in 4 of 21 bars in Changwon. Our study concludes that the greatest decrease in PM2.5 concentrations in bars was observed after the regulation covering all bars was implemented. However, despite the comprehensive ban, smoking was observed in bars in Changwon. Strict compliance with the regulations is needed to improve indoor air quality further.

Domains of the Florida Performance Measurement System.

ERIC Educational Resources Information Center

Florida State Dept. of Education, Tallahassee.

This monograph sets forth in detail the concepts included in the five domains of teaching as identified by the Florida Coalition for the Development of a Performance Evaluation System. The first domain, planning, includes the concepts: (1) content coverage; (2) utilization of instructional materials; (3) activity structure; (4) goal focusing; and…

Fatigue of reinforcing bars during hydro-demolition

NASA Astrophysics Data System (ADS)

Hyland, C. W. K.; Ouwejan, A.

2017-05-01

Reinforcing steel fractured during hydro-demolition of a reinforced concrete pier head due to low cycle flexural fatigue from vibration caused by impact of the high pressure water jet on the exposed length of the bars. Research into the fatigue performance of steel reinforcing steel tends to focus on the high cycle axial performance in reinforced concrete members and re-bending behaviour. However with the increasing use of hydro-demolition of concrete structures as part of remediation works care is required to ensure the steel reinforcement exposed to the high pressure jet of water is not going to suffer relatively low cycle flexural damage that may compromise the designed performance of the completed reinforced concrete structure. This paper describes the failure assessment, fatigue analysis, and metallographic examination that was undertaken. It was found that the rib to flank transition radius on the reinforcement steel was small enough to cause a significant stress concentration effect and was the location of fatigue crack growth. A relatively simple analysis using the maximum unrestrained cantilevered bar length and force exerted by the water jet was used to calculate the maximum expected bending moment. This was compared to the bending capacity at initiation of yielding at the rib flank transition accounting for stress concentration effects. This showed that the observed cyclic reversing ductile crack growth and fracture of the H25 bars was consistent with the loading applied. A method is proposed based on these observations to assess suitable limits for unrestrained bar lengths or maximum working offset of the water jet from the point of bar restraint when undertaking hydro-demolition work. The fatigue critical performance requirements of AS/NZS4671 500E bars are also therefore compared with those of BS4449:2005 and PN EN/ISO 15630-1:2011 for comparable 500C bars

Energy Drinks and Food Bars: Power or Hype?

MedlinePlus

... Staying Safe Videos for Educators Search English Español Energy Drinks and Food Bars: Power or Hype? KidsHealth / ... nutritivas: ¿Energía o mera exageración? The Buzz on Energy Foods Energy drinks and nutrition bars often make ...

NMR assignments of the N-terminal domain of Nephila clavipes spidroin 1

PubMed Central

Parnham, Stuart; Gaines, William A.; Duggan, Brendan M.; Marcotte, William R.

2011-01-01

The building blocks of spider dragline silk are two fibrous proteins secreted from the major ampullate gland named spidroins 1 and 2 (MaSp1, MaSp2). These proteins consist of a large central domain composed of approximately 100 tandem copies of a 35–40 amino acid repeat sequence. Non-repetitive N and C-terminal domains, of which the C-terminal domain has been implicated to transition from soluble and insoluble states during spinning, flank the repetitive core. The N-terminal domain until recently has been largely unknown due to difficulties in cloning and expression. Here, we report nearly complete assignment for all 1H, 13C, and 15N resonances in the 14 kDa N-terminal domain of major ampullate spidroin 1 (MaSp1-N) of the golden orb-web spider Nephila clavipes. PMID:21152998

The pterygoalar bar: A meta-analysis of its prevalence, morphology and morphometry.

PubMed

Pękala, Przemysław A; Henry, Brandon Michael; Pękala, Jakub R; Frączek, Paulina A; Taterra, Dominik; Natsis, Konstantinos; Piagkou, Maria; Skrzat, Janusz; Tomaszewska, Iwona M

2017-09-01

The pterygoalar (PA) bar is a bony bridge resulting from the partial or complete ossification of a PA ligament. The aim of this meta-analysis was to systematically analyze and provide the most comprehensive data on the prevalence, morphology and topographical anatomy of the PA bar. A comprehensive search of the major electronic databases (PubMed, Embase, ScienceDirect, SciELO, BIOSIS, and Web of Science) was conducted in order to identify relevant studies. Studies reporting the prevalence, side of occurrence, gender dimorphism and morphometry of the PA bar were included in the current study. A total of 25 articles (n = 16,168 subjects) were included in the meta-analysis. The overall pooled prevalence of the complete PA bar was 4.4% (95% CI: 3.0-6.0) and of the incomplete was 8.4% (95% CI: 4.6-13.3). The PA bar was most often observed unilaterally, on the left side. Analysis of geographical subgroups revealed considerable differences, with the lowest prevalence rates in Europe for both incomplete and complete PA bars. Considering the prevalence and anatomical characteristics of the PA bar, caution is recommended while planning or performing transfacial needle approach to the foramen ovale and when considering a differential diagnosis for nerve compression or entrapment syndromes. Copyright © 2017 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Search for the Standard Model Higgs Boson in ZH → v$$\\bar{v}$$b$$\\bar{b}$$ channel in p$$\\bar{p}$$ collisions at √s= 1.96 TeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dubey, Abhinav

2011-01-01

A search for the standard model Higgs boson is performed in 5.2 fb -1 of pmore » $$\\bar{p}$$ collisions at p √s = 1.96 TeV, collected with the DØ detector at the Fermilab Tevatron. The final state considered is a pair of b jets with large missing transverse energy, as expected from p$$\\bar{p}$$→ ZH → v$$\\bar{v}$$b$$\\bar{b}$$ production. The search is also sensitive to the WH → ℓvb$$\\bar{b}$$ channel, where the charged lepton is not identified. Boosted decision trees are used to discriminate signal from background. Good agreement is observed between data and expected backgrounds, and, for a Higgs-boson mass of 115 GeV, a limit is set at 95% C.L. on the cross section multiplied by branching fraction of (p$$\\bar{p}$$ → (Z/W)H) × (H → b$$\\bar{b}$$) that is a factor 4.57 expected and 3.73 observed larger than the value expected from the standard model.« less

PREDICTIONS FOR $B \\to \\tau \\bar{\\mu} + \\mu \\bar{\\tau}$

NASA Astrophysics Data System (ADS)

Boubaa, Dris; Datta, Alakabha; Duraisamy, Murugeswaran; Khalil, Shaaban

2013-12-01

The observation of B -> τ \\bar {μ } + μ \\bar {τ } at present experiments would be a clear sign of new physics. In this paper, we calculate this process in an extended Higgs sector framework where the decay is mediated by the exchange of spin zero particle with flavor changing neutral current couplings. If we identify the scalar with the newly discovered state at LHC with a mass 125 GeV then we find that, after imposing all experimental constraints, the BR(Bs -> τ \\bar {μ } + μ \\bar {τ }) can be as high as 10-6 and BR (Bd -> τ \\bar {μ } + μ \\bar {τ }) can be as high as 10-7. We also calculate this process in the minimal supersymmetric standard model and find the BR(Bs ->τ \\bar {μ } + μ \\bar {τ }) is typically of the order 10-8.

Why Buckling Stellar Bars Weaken in Disk Galaxies

NASA Astrophysics Data System (ADS)

Martinez-Valpuesta, Inma; Shlosman, Isaac

2004-09-01

Young stellar bars in disk galaxies experience a vertical buckling instability that terminates their growth and thickens them, resulting in a characteristic peanut/boxy shape when viewed edge-on. Using N-body simulations of galactic disks embedded in live halos, we have analyzed the bar structure throughout this instability and found that the outer (approximately) third of the bar dissolves completely while the inner part (within the vertical inner Lindblad resonance) becomes less oval. The bar acquires the frequently observed peanut/boxy-shaped isophotes. We also find that the bar buckling is responsible for a mass injection above the plane, which is subsequently trapped by specific three-dimensional families of periodic orbits of particular shapes explaining the observed isophotes, in line with previous work. Using a three-dimensional orbit analysis and surfaces of sections, we infer that the outer part of the bar is dissolved by a rapidly widening stochastic region around its corotation radius-a process related to the bar growth. This leads to a dramatic decrease in the bar size, decrease in the overall bar strength, and a mild increase in its pattern speed but is not expected to lead to a complete bar dissolution. The buckling instability appears primarily responsible for shortening the secular diffusion timescale to a dynamical one when building the boxy isophotes. The sufficiently long timescale of the described evolution, ~1 Gyr, can affect the observed bar fraction in the local universe and at higher redshifts, both through reduced bar strength and the absence of dust offset lanes in the bar.

Stir bar sorptive extraction combined with high performance liquid chromatography-ultraviolet/inductively coupled plasma mass spectrometry for analysis of thyroxine in urine samples.

PubMed

Fan, Wenying; Mao, Xiangju; He, Man; Chen, Beibei; Hu, Bin

2013-11-29

tIn this work, polyethyleneglycol (PEG)/hydroxyl polydimethylsiloxane (OH-PDMS)/γ -mercaptopropyltrimethoxysilane (γ -MPTS) coated stir bar was prepared by sol–gel process and its extraction performance for the extraction of amphoteric thyroxines (3,3',5,5'-tetraiodothyronin, T(4); 3,3',5-triiodothyronine, T(3); reversed-3,3',5-triiodothyronine, rT(3)) and their metabolite (3,5-diiodothyronine,T2) was studied. The preparation reproducibility of PEG/OH-PDMS/γ -MPTS coated stir bar was investigated, and the relative standard deviations (RSDs) in the same batch and among different batches were 3.3–14.3% (n = 5) and 7.7–16.6% (n = 3), respectively. The prepared PEG/OH-PDMS/γ -MPTS coated stir bar could be reused for more than 20 times. Based on this fact, a novel method of stir bar sorptive extraction (SBSE) combined with high performance liquid chromatography (HPLC)-ultraviolet (UV)and HPLC-inductively coupled plasma mass spectrometry (ICP-MS) for the analysis of target thyroxinesin human urine samples was developed. The influencing factors of SBSE, such as sample pH, extraction time, stirring rate, salt effect, desorption solution and desorption time, were studied in detail, and the analytical performance of the proposed method was evaluated under the optimized conditions. The enrichment factors (EFs) of the developed method for four target thyroxines were in the range of 14.9–70.4(theoretical enrichment factor was 100). The RSDs were ranging from 4.0% to 13.8% for SBSE-HPLC-UV (c = 25 μg/L, n = 6) and from 3.7% to 6.1% for SBSE-HPLC-ICP-MS (c = 0.5 μg/L, n = 5). The linear range obtained by SBSE-HPLC-UV was 2–500 μg/L for T(2)and 5–500 μg/L for rT3, T(3)and T(4), with correlation coefficients (r) ranging from 0.9957 to 0.9998, respectively, while the linear range obtained by SBSE-HPLC-ICP-MS was 0.05–500 μg/L for T(2) and rT(3), 0.10–200 μg/L for T(3) and 0.05–200 μg/L for T(4)with r ranging from 0.9979 to 0.9998, respectively. The

Fractured toughness of Si3N4 measured with short bar chevron-notched specimens

NASA Technical Reports Server (NTRS)

Salem, J. A.; Shannon, J. L., Jr.

1985-01-01

The short bar chevron-notched specimen is used to measure the plane strain fracture toughness of hot pressed Si3N4. Specimen proportions and chevron-notch angle are varied, thereby varying the amount of crack extension to maximum load (upon which K sub IC is based). The measured toughness (4.68 + or - 0.19 MNm to the 3/2 power) is independent of these variations, inferring that the material has a flat crack growth resistance curve.

Fracture toughness of Si3N4 measured with short bar chevron-notched specimens

NASA Technical Reports Server (NTRS)

Salem, Jonathan A.; Shannon, John L., Jr.

1987-01-01

The short bar chevron-notched specimen is used to measure the plane strain fracture toughness of hot pressed Si3N4. Specimen proportions and chevron-notch angle are varied, thereby varying the amount of crack extension to maximum load (upon which K sub IC is based). The measured toughness (4.68 + or 0.19 MNm to the 3/2 power) is independent of these variations, inferring that the material has a flat crack growth resistance curve.

Formation of Tidally Induced Bars in Galactic Flybys: Prograde versus Retrograde Encounters

NASA Astrophysics Data System (ADS)

Łokas, Ewa L.

2018-04-01

Bars in disk galaxies can be formed by interactions with other systems, including those of comparable mass. It has long been established that the effect of such interactions on galaxy morphology depends strongly on the orbital configuration, in particular the orientation of the intrinsic spin of the galactic disk with respect to its orbital angular momentum. Prograde encounters modify the morphology strongly, including the formation of tidally induced bars, while retrograde flybys should have little effect on morphology. Recent works on the subject reached conflicting conclusions, one using the impulse approximation and claiming no dependence on this angle in the properties of tidal bars. To resolve the controversy, we performed self-consistent N-body simulations of hyperbolic encounters between two identical Milky Way-like galaxies assuming different velocities and impact parameters, with one of the galaxies on a prograde and the other on a retrograde orbit. The galaxies were initially composed of an exponential stellar disk and an NFW dark halo, and they were stable against bar formation in isolation for 3 Gyr. We find that strong tidally induced bars form only in galaxies on prograde orbits. For smaller impact parameters and lower relative velocities, the bars are stronger and have lower pattern speeds. Stronger bars undergo extended periods of buckling instability that thicken their vertical structure. The encounters also lead to the formation of two-armed spirals with strength inversely proportional to the strength of the bars. We conclude that proper modeling of prograde and retrograde encounters cannot rely on the simplest impulse approximation.

Performance of a bridge deck with glass fiber reinforced polymer bars as the top mat of reinforcement.

DOT National Transportation Integrated Search

2005-01-01

The purpose of this research was to investigate the performance of glass fiber reinforced polymer (GFRP) bars as reinforcement for concrete decks. Today's rapid bridge deck deterioration is calling for a replacement for steel reinforcement. The advan...

Characterization of seismicity at Volcán Barú, Panama: May 2013 through April 2014

NASA Astrophysics Data System (ADS)

Hopp, Chet J.; Waite, Gregory P.

2016-12-01

Volcán Barú, in the western province of Chiriquí, is Panama's youngest and most active volcano. Although Barú has experienced no historic eruptions, there have been four eruptive episodes in the last 1600 years, the most recent occurring 400-500 years ago (Sherrod et al., 2007). In addition, there have been four reported earthquake swarms in the last 100 years. The most recent swarm occurred in May of 2006, prompting a USGS hazard assessment (Sherrod et al., 2007). In order to characterize local seismicity and provide a reference for future monitoring efforts, we established a seismic network that operated from May 2013 through April 2014. The network consisted of eight temporary, single-component, short-period sensors loaned by OSOP Panama, and three permanent stations distributed over a 35 by 15 km area. During operation of the network, 91 local events were detected and located. These events were used to calculate a new 1-D velocity model for the region surrounding Barú. Of particular interest was a cluster of events located less than 5 km east of Barú at a depth of roughly 5 km. We used a template matching detection technique to identify another 47 smaller magnitude events in the area of this cluster. The largest events in the cluster exhibit a broad range of frequencies extending up to 20 Hz and focal mechanisms calculated for eight of the events suggest strike-slip and reverse faulting are the predominant source processes. The directions of maximum compression shown by these focal mechanisms are approximately radial with respect to the volcano, which may reflect the influence of a magmatic source beneath the edifice.

Sampling Approaches for Multi-Domain Internet Performance Measurement Infrastructures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calyam, Prasad

2014-09-15

The next-generation of high-performance networks being developed in DOE communities are critical for supporting current and emerging data-intensive science applications. The goal of this project is to investigate multi-domain network status sampling techniques and tools to measure/analyze performance, and thereby provide “network awareness” to end-users and network operators in DOE communities. We leverage the infrastructure and datasets available through perfSONAR, which is a multi-domain measurement framework that has been widely deployed in high-performance computing and networking communities; the DOE community is a core developer and the largest adopter of perfSONAR. Our investigations include development of semantic scheduling algorithms, measurement federationmore » policies, and tools to sample multi-domain and multi-layer network status within perfSONAR deployments. We validate our algorithms and policies with end-to-end measurement analysis tools for various monitoring objectives such as network weather forecasting, anomaly detection, and fault-diagnosis. In addition, we develop a multi-domain architecture for an enterprise-specific perfSONAR deployment that can implement monitoring-objective based sampling and that adheres to any domain-specific measurement policies.« less

Tidally Induced Bars of Galaxies in Clusters

NASA Astrophysics Data System (ADS)

Łokas, Ewa L.; Ebrová, Ivana; del Pino, Andrés; Sybilska, Agnieszka; Athanassoula, E.; Semczuk, Marcin; Gajda, Grzegorz; Fouquet, Sylvain

2016-08-01

Using N-body simulations, we study the formation and evolution of tidally induced bars in disky galaxies in clusters. Our progenitor is a massive, late-type galaxy similar to the Milky Way, composed of an exponential disk and a Navarro-Frenk-White dark matter halo. We place the galaxy on four different orbits in a Virgo-like cluster and evolve it for 10 Gyr. As a reference case, we also evolve the same model in isolation. Tidally induced bars form on all orbits soon after the first pericenter passage and survive until the end of the evolution. They appear earlier, are stronger and longer, and have lower pattern speeds for tighter orbits. Only for the tightest orbit are the properties of the bar controlled by the orientation of the tidal torque from the cluster at pericenter. The mechanism behind the formation of the bars is the angular momentum transfer from the galaxy stellar component to its halo. All of the bars undergo extended periods of buckling instability that occur earlier and lead to more pronounced boxy/peanut shapes when the tidal forces are stronger. Using all simulation outputs of galaxies at different evolutionary stages, we construct a toy model of the galaxy population in the cluster and measure the average bar strength and bar fraction as a function of clustercentric radius. Both are found to be mildly decreasing functions of radius. We conclude that tidal forces can trigger bar formation in cluster cores, but not in the outskirts, and thus can cause larger concentrations of barred galaxies toward the cluster center.

Determination of sulfonamides in butter samples by ionic liquid magnetic bar liquid-phase microextraction high-performance liquid chromatography.

PubMed

Wu, Lijie; Song, Ying; Hu, Mingzhu; Xu, Xu; Zhang, Hanqi; Yu, Aimin; Ma, Qiang; Wang, Ziming

2015-01-01

A novel, simple, and environmentally friendly pretreatment method, ionic liquid magnetic bar liquid-phase microextraction, was developed for the determination of sulfonamides in butter samples by high-performance liquid chromatography. The ionic liquid magnetic bar was prepared by inserting a stainless steel wire into the hollow of a hollow fiber and immobilizing ionic liquid in the micropores of the hollow fiber. In the extraction process, the ionic liquid magnetic bars were used to stir the mixture of sample and extraction solvent and enrich the sulfonamides in the mixture. After extraction, the analyte-adsorbed ionic liquid magnetic bars were readily isolated with a magnet from the extraction system. It is notable that the present method was environmentally friendly since water and only several microliters of ionic liquid were used in the whole extraction process. Several parameters affecting the extraction efficiency were investigated and optimized, including the type of ionic liquid, sample-to-extraction solvent ratio, the number of ionic liquid magnetic bars, extraction temperature, extraction time, salt concentration, stirring speed, pH of the extraction solvent, and desorption conditions. The recoveries were in the range of 73.25-103.85 % and the relative standard deviations were lower than 6.84 %. The experiment results indicated that the present method was effective for the extraction of sulfonamides in high-fat content samples.

Mesoscopic bar magnet based on ε-Fe2O3 hard ferrite.

PubMed

Ohkoshi, Shin-Ichi; Namai, Asuka; Yamaoka, Takehiro; Yoshikiyo, Marie; Imoto, Kenta; Nasu, Tomomichi; Anan, Shizuka; Umeta, Yoshikazu; Nakagawa, Kosuke; Tokoro, Hiroko

2016-06-07

Ferrite magnets have a long history. They are used in motors, magnetic fluids, drug delivery systems, etc. Herein we report a mesoscopic ferrite bar magnet based on rod-shaped ε-Fe2O3 with a large coercive field (>25 kOe). The ε-Fe2O3-based bar magnet is a single crystal with a single magnetic domain along the longitudinal direction. A wide frequency range spectroscopic study shows that the crystallographic a-axis of ε-Fe2O3, which corresponds to the longitudinal direction of the bar magnet, plays an important role in linear and non-linear magneto-optical transitions, phonon modes, and the magnon (Kittel mode). Due to its multiferroic property, a magnetic-responsive non-linear optical sheet is manufactured as an application using an ε-Fe2O3-based bar magnet, resin, and polyethylene terephthalate. Furthermore, from the viewpoint of the large coercive field property, we demonstrate that a mesoscopic ε-Fe2O3 bar magnet can be used as a magnetic force microscopy probe.

Mesoscopic bar magnet based on ɛ-Fe2O3 hard ferrite

NASA Astrophysics Data System (ADS)

Ohkoshi, Shin-Ichi; Namai, Asuka; Yamaoka, Takehiro; Yoshikiyo, Marie; Imoto, Kenta; Nasu, Tomomichi; Anan, Shizuka; Umeta, Yoshikazu; Nakagawa, Kosuke; Tokoro, Hiroko

2016-06-01

Ferrite magnets have a long history. They are used in motors, magnetic fluids, drug delivery systems, etc. Herein we report a mesoscopic ferrite bar magnet based on rod-shaped ɛ-Fe2O3 with a large coercive field (>25 kOe). The ɛ-Fe2O3-based bar magnet is a single crystal with a single magnetic domain along the longitudinal direction. A wide frequency range spectroscopic study shows that the crystallographic a-axis of ɛ-Fe2O3, which corresponds to the longitudinal direction of the bar magnet, plays an important role in linear and non-linear magneto-optical transitions, phonon modes, and the magnon (Kittel mode). Due to its multiferroic property, a magnetic-responsive non-linear optical sheet is manufactured as an application using an ɛ-Fe2O3-based bar magnet, resin, and polyethylene terephthalate. Furthermore, from the viewpoint of the large coercive field property, we demonstrate that a mesoscopic ɛ-Fe2O3 bar magnet can be used as a magnetic force microscopy probe.

Non-specific activities of the major herbicide-resistance gene BAR.

PubMed

Christ, Bastien; Hochstrasser, Ramon; Guyer, Luzia; Francisco, Rita; Aubry, Sylvain; Hörtensteiner, Stefan; Weng, Jing-Ke

2017-12-01

Bialaphos resistance (BAR) and phosphinothricin acetyltransferase (PAT) genes, which convey resistance to the broad-spectrum herbicide phosphinothricin (also known as glufosinate) via N-acetylation, have been globally used in basic plant research and genetically engineered crops 1-4 . Although early in vitro enzyme assays showed that recombinant BAR and PAT exhibit substrate preference toward phosphinothricin over the 20 proteinogenic amino acids 1 , indirect effects of BAR-containing transgenes in planta, including modified amino acid levels, have been seen but without the identification of their direct causes 5,6 . Combining metabolomics, plant genetics and biochemical approaches, we show that transgenic BAR indeed converts two plant endogenous amino acids, aminoadipate and tryptophan, to their respective N-acetylated products in several plant species. We report the crystal structures of BAR, and further delineate structural basis for its substrate selectivity and catalytic mechanism. Through structure-guided protein engineering, we generated several BAR variants that display significantly reduced non-specific activities compared with its wild-type counterpart in vivo. The transgenic expression of enzymes can result in unintended off-target metabolism arising from enzyme promiscuity. Understanding such phenomena at the mechanistic level can facilitate the design of maximally insulated systems featuring heterologously expressed enzymes.

Metal/polymer composite Nuss bar for minimally invasive bar removal after Pectus Excavatum treatment: FEM simulations.

PubMed

Ricotti, Leonardo; Ciuti, Gastone; Ghionzoli, Marco; Messineo, Antonio; Menciassi, Arianna

2014-12-01

This study aims at assessing the mechanical behavior of a composite metal/polymer bar to be implanted in the retrosternal position, in order to correct chest wall deformities, such as Pectus Excavatum. A 300-mm-long, 12.7-mm-wide, and 3.5-mm-thick Nuss bar was considered, made of different metals and biodegradable polymers, fixed at its extremities, and with a constant force of 250 N applied on its center. Two different geometries for the metal elements to be embedded in the polymeric matrix were tested: in the former, thin metal sheets and in the latter, cylindrical metal reinforcing rods were considered. Finite element method simulation results are reported, in terms of maximum stress and strain of the bar. Furthermore, the maximum stress values obtained by varying metal sheet thickness or rod diameter (and therefore the volumetric percentage of metal within the matrix) for different material combinations are also shown; optimal configuration for the Pectus Excavatum treatment was finally identified for a composite Nuss bar. Copyright © 2014 John Wiley & Sons, Ltd.

Water-compatible graphene oxide/molecularly imprinted polymer coated stir bar sorptive extraction of propranolol from urine samples followed by high performance liquid chromatography-ultraviolet detection.

PubMed

Fan, Wenying; He, Man; You, Linna; Zhu, Xuewei; Chen, Beibei; Hu, Bin

2016-04-22

Due to the high selectivity and stability, molecularly imprinted polymers (MIPs) have been successfully applied in stir bar sorptive extraction (SBSE) as a special coating to improve the selective extraction capability for target analytes. However, traditional MIPs usually suffer from incompatibility in aqueous media and low adsorption capacity, which limit the application of MIP coated stir bar in aqueous samples. To solve these problems, a water-compatible graphene oxides (GO)/MIP composite coated stir bar was prepared in this work by in situ polymerization. The prepared water-compatible GO/MIP coated stir bar presented good mechanical strength and chemical stability, and its recognition ability in aqueous samples was improved due to the polymerization of MIP in water environment, the adsorption capacity for target analytes was also increased by the addition of GO in MIP pre-polymer solution. Based on it, a method of water-compatible GO/MIP coated stir bar sorptive extraction combined with high performance liquid chromatography-ultraviolet detector (HPLV-UV) was proposed for the analysis of propranolol (PRO) in aqueous solution. The influencing factors of SBSE, such as sample pH, salt effect, stirring rate, extraction time, desorption solvent and desorption time, were optimized, and the analytical performance of the developed SBSE-HPLC-UV method was evaluated under the optimized conditions. The limit of detection (LOD) of the proposed method for PRO was about 0.37 μg L(-1), and the enrichment factor (EF) was 59.7-fold (theoretical EF was 100-fold). The reproducibility was also investigated at concentrations of 5 μg L(-1) and the relative standard deviation (RSD) was found to be 7.3% (n=7). The proposed method of GO/MIP coating-SBSE-HPLC-UV was successfully applied for the assay of the interested PRO drug in urine samples, and further extended to the investigation of the excretion of the drugs by monitoring the variation of the concentration of PRO in urine

Experimental evaluation of low-pass shock isolation performance of elastomers using frequency-based Kolsky bar analyses

DOE PAGES

Knight, Marlene E.; Sanborn, Brett; Song, Bo; ...

2017-01-26

Elastomeric materials are used as shock isolation materials in a variety of environments to dampen vibrations and/or absorb energy from external impact to minimize energy transfer between two objects or bodies. Some applications require the shock isolation materials to behave as a low-pass mechanical filter to mitigate the shock/impact at high frequencies but transmit the energy at low frequencies with minimal attenuation. To fulfill this requirement, a shock isolation material needs to be carefully evaluated and selected with proper experimental design, procedures, and analyses. In this study, a Kolsky bar was modified with precompression (up to 15.5 kN) and confinementmore » capabilities to evaluate low-pass shock isolation performance in terms of acceleration attenuation through a variety of elastomers. Also investigated were the effects of preload and specimen geometry on the low-pass shock isolation response.« less

Scaleable multi-format QCW pump stacks based on 200W laser diode bars and mini bars at 808nm and 940nm

NASA Astrophysics Data System (ADS)

Berk, Yuri; Karni, Yoram; Klumel, Genady; Openhaim, Yaakov; Cohen, Shalom; Yanson, Dan

2011-03-01

Advanced solid state laser architectures place increasingly demanding requirements on high-brightness, low-cost QCW laser diode pump sources, with custom apertures both for side and end rod pumping configurations. To meet this need, a new series of scaleable pump sources at 808nm and 940nm was developed. The stacks, available in multiple output formats, allow for custom aperture filling by varying both the length and quantity of stacked laser bars. For these products, we developed next-generation laser bars based on improved epitaxial wafer designs delivering power densities of 20W/mm of emission aperture. With >200W of peak QCW power available from a full-length 1cm bar, we have demonstrated power scaling to over 2kW in 10-bar stacks with 55% wall plug efficiency. We also present the design and performance of several stack configurations using full-length and reduced-length (mini) bars that demonstrate the versatility of both the bar and packaging designs. We illustrate how the ROBUST HEAD packaging technology developed at SCD is capable of accommodating variable bar length, pitch and quantity for custom rod pumping geometries. The excellent all-around performance of the stacks is supported by reliability data in line with the previously reported 20 Gshot space-grade qualification of SCD's stacks.

Spatial dynamics of bar-headed geese migration in the context of H5N1

USGS Publications Warehouse

Bourouiba, L.; Wu, Jianhong; Newman, S.; Takekawa, John Y.; Natdorj, T.; Batbayar, N.; Bishop, C.M.; Hawkes, L.A.; Butler, P.J.; Wikelski, M.

2010-01-01

Virulent outbreaks of highly pathogenic avian influenza (HPAI) since 2005 have raised the question about the roles of migratory and wild birds in the transmission of HPAI. Despite increased monitoring, the role of wild waterfowl as the primary source of the highly pathogenic H5N1 has not been clearly established. The impact of outbreaks of HPAI among species of wild birds which are already endangered can nevertheless have devastating consequences for the local and non-local ecology where migratory species are established. Understanding the entangled dynamics of migration and the disease dynamics will be key to prevention and control measures for humans, migratory birds and poultry. Here, we present a spatial dynamic model of seasonal migration derived from first principles and linking the local dynamics during migratory stopovers to the larger scale migratory routes. We discuss the effect of repeated epizootic at specific migratory stopovers for bar-headed geese (Anser indicus). We find that repeated deadly outbreaks of H5N1 on stopovers during the autumn migration of bar-headed geese could lead to a larger reduction in the size of the equilibrium bird population compared with that obtained after repeated outbreaks during the spring migration. However, the opposite is true during the first few years of transition to such an equilibrium. The age-maturation process of juvenile birds which are more susceptible to H5N1 reinforces this result.

Machine learning techniques in searches for$$t\\bar{t}$$h in the h → $$b\\bar{b}$$ decay channel

DOE PAGES

Santos, Robert; Nguyen, M.; Webster, Jordan; ...

2017-04-10

Study of the production of pairs of top quarks in association with a Higgs boson is one of the primary goals of the Large Hadron Collider over the next decade, as measurements of this process may help us to understand whether the uniquely large mass of the top quark plays a special role in electroweak symmetry breaking. Higgs bosons decay predominantly to bmore » $$\\bar{_b}$$, yielding signatures for the signal that are similar to t$$\\bar{_t}$$ + jets with heavy flavor. Though particularly challenging to study due to the similar kinematics between signal and background events, such final states (t$$\\bar{_t}$$b$$\\bar{b}$$) are an important channel for studying the top quark Yukawa coupling. This paper presents a systematic study of machine learning (ML) methods for detecting t$$\\bar{_t}$$h in the h → b$$\\bar{b}$$ decay channel. Among the seven ML methods tested, we show that neural network models outperform alternative methods. In addition, two neural models used in this paper outperform NeuroBayes, one of the standard algorithms used in current particle physics experiments. We further study the effectiveness of ML algorithms by investigating the impact of feature set and data size, as well as the depth of the networks for neural models. We demonstrate that an extended feature set leads to improvement of performance over basic features. Furthermore, the availability of large samples for training is found to be important for improving the performance of the techniques. For the features and the data set studied here, neural networks of more layers deliver comparable performance to their simpler counterparts.« less

Machine learning techniques in searches for$$t\\bar{t}$$h in the h → $$b\\bar{b}$$ decay channel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Santos, Robert; Nguyen, M.; Webster, Jordan

Study of the production of pairs of top quarks in association with a Higgs boson is one of the primary goals of the Large Hadron Collider over the next decade, as measurements of this process may help us to understand whether the uniquely large mass of the top quark plays a special role in electroweak symmetry breaking. Higgs bosons decay predominantly to bmore » $$\\bar{_b}$$, yielding signatures for the signal that are similar to t$$\\bar{_t}$$ + jets with heavy flavor. Though particularly challenging to study due to the similar kinematics between signal and background events, such final states (t$$\\bar{_t}$$b$$\\bar{b}$$) are an important channel for studying the top quark Yukawa coupling. This paper presents a systematic study of machine learning (ML) methods for detecting t$$\\bar{_t}$$h in the h → b$$\\bar{b}$$ decay channel. Among the seven ML methods tested, we show that neural network models outperform alternative methods. In addition, two neural models used in this paper outperform NeuroBayes, one of the standard algorithms used in current particle physics experiments. We further study the effectiveness of ML algorithms by investigating the impact of feature set and data size, as well as the depth of the networks for neural models. We demonstrate that an extended feature set leads to improvement of performance over basic features. Furthermore, the availability of large samples for training is found to be important for improving the performance of the techniques. For the features and the data set studied here, neural networks of more layers deliver comparable performance to their simpler counterparts.« less

Effects of the Bar Strength of Gaseous Features in Barred Galaxies

NASA Astrophysics Data System (ADS)

Kim, Woong-Tae; Seo, W.; Kim, Y.

2013-01-01

Barred galaxies commonly possess gaseous structures such as a pair of dust lanes, a nuclear ring, and nuclear spirals at their centers. We use hydrodynamic simulations to study the physical properties of the gaseous structures in barred galaxies and their relationships with the bar strength. We vary the bar mass fbar relative to the spheroidal component as well as its aspect ratio. We derive expressions for the bar strength Qb and the radius where the maximum bar torque occurs. When applied to observations, these expressions suggest that bars in real galaxies are most likely to have fbar = 0.25-0.5. Dust lanes approximately follow one of x1-orbits and tend to be more straight under a stronger and more elongated bar. A nuclear ring of a conventional x2 type forms only when the bar is not so massive or elongated. The radius of an x2-type ring is generally smaller than the inner Lindblad resonance, decreases systematically with increasing Qb, evidencing that the ring position is not determined by the resonance but by the bar strength. Nuclear spirals exist only when the ring is of the x2-type and sufficiently large in size. Unlike the other features, nuclear spirals are transient in that they start out as being tightly-wound and weak, and then due to the nonlinear effect unwind and become stronger until turning into shocks, with an unwinding rate higher for larger Qb. These results suggest that the bar strength is the primary factor that determine the properties of gaseous structures in barred galaxies.

Glide Dislocations Dissociation in Inversion Domain Boundaries of Plastically Deformed Aluminium Nitride

NASA Astrophysics Data System (ADS)

Feregotto, Virginia; Michel, Jean-Pierre

1996-09-01

A ten per cent plastic deformation of polycrystalline aluminium nitride, at a temperature ranging from 1500 to 1650 ^{circ}C creates a new kind of intragranular defect. Observed by transmission electron microscopy, the look like torsion subboundaries created by dislocations with 1/3<~ngle11bar{2}0rangle Burgers vectors and so nodes are dissociated into Shockley partials. They are located in the basal plane. In fact, these defects appear only in the plane areas of grown-in defects, the inversion domain boundaries. The formation of these faulted networks is interpreted as being the ultimate stage of the interactions between inversion domain boundaries and glide dislocations. Une déformation plastique de 10 % de nitrure d'aluminium polycristallin, entre 1500 et 1650 ^{circ}C introduit un nouveau type de défauts intragranulaires. Au microscope électronique par transmission, ils apparaissent comme des sous-joints de torsion créés par des dislocations de vecteurs de Burgers 1/3<~ngle11bar{2}0rangle dont les nœuds triples sont dissociés en partielles de Shockley ; ils sont situés dans le plan de base. En fait, ces défauts ne se produisent que sur les parties planes de défauts originels, les parois de domaines d'inversion. La formation de ces réseaux fautés est analysée comme l'ultime stade des interactions entre parois de domaines d'inversion et dislocations de glissement.

Surfactant antimony enhanced indium incorporation on InGaN (000 1 bar) surface: A DFT study

NASA Astrophysics Data System (ADS)

Zhang, Yiou; Zhu, Junyi

2016-03-01

InGaN is an ideal alloy system for optoelectronic devices due its tunable band gap. Yet high-quality InGaN requires high In concentration, which is a challenging issue that limits its use in green-light LEDs and other devices. In this paper, we investigated the surfactant effect of Sb on the In incorporation on InGaN (000 1 bar) surface via first-principles approaches. Surface phase diagram was also constructed to determine surface structures under different growth conditions. By analyzing surface stress under different structures, we found that Sb adatom can induce tensile sites in the cation layer, enhancing the In incorporation. These findings may provide fundamental understandings and guidelines for the growth of InGaN with high In concentration.

Determination of semicarbazide in fish by molecularly imprinted stir bar sorptive extraction coupled with high performance liquid chromatography.

PubMed

Tang, Tang; Wei, Fangdi; Wang, Xu; Ma, Yujie; Song, Yueyue; Ma, Yunsu; Song, Quan; Xu, Guanhong; Cen, Yao; Hu, Qin

2018-02-15

A novel molecularly imprinted stir bar (MI-SB) for sorptive extraction of semicarbazide (SEM) was prepared in present paper. The coating of the stir bar was characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, dynamic adsorption and static adsorption tests. The saturated adsorption of MI-SB was about 4 times over that of non-imprinted stir bar (NI-SB). The selectivity of MI-SB for SEM was much better than NI-SB. A method to determine SEM was established by coupling MI-SB sorptive extraction with HPLC-UV. The liner range was 1-100ng/mL for SEM with a correlation coefficient of 0.9985. The limit of detection was about 0.59ng/mL, which was below the minimum required performance limit of SEM in meat products regulated by European Union. The method was applied to the determination of SEM in fish samples with satisfactory results. Copyright © 2018 Elsevier B.V. All rights reserved.

Multi-stir bar sorptive extraction for analysis of odor compounds in aqueous samples.

PubMed

Ochiai, Nobuo; Sasamoto, Kikuo; Ieda, Teruyo; David, Frank; Sandra, Pat

2013-11-08

As reproducible coating of stir bars with more polar phases was found to be very difficult, a supporting grid was used in the development of an ethyleneglycol-modified Silicone (EG Silicone) coated stir bar. This new polar coating showed good performance for the extraction of polar solutes, but long term use also showed degradation of the coating due to friction while stirring. In order to address the lower robustness of the EG Silicone stir bar which has a much softer coating compared to a conventional polydimethylsiloxane (PDMS) stir bar, a novel SBSE procedure termed multi-SBSE ((m)SBSE) was developed. (m)SBSE consists of the robust PDMS stir bar stirring at the bottom of the vial and the EG Silicone stir bar attached on the inner side wall of the vial (a magnetic clip is used for the set-up). After extraction, the two stir bars are placed in a single glass desorption liner and are simultaneously thermally desorbed. The desorbed compounds were analyzed by thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). Compared to conventional SBSE, (m)SBSE provides more uniform enrichment of a wide range of odor compounds in aqueous sample since both stir bars can complement each other, while eliminating the damage of the EG Silicone phase during the extraction. The robustness of the EG Silicone stir bar was dramatically increased and more than 30 extraction and desorption cycles were possible without loss in performance. The recoveries for polar solutes such as 2-acetyl pyrrole (logKow: 0.55), benzyl alcohol (logKow: 1.08), guaiacol (logKow: 1.34), and indole (logKow: 2.05) were increased by a factor of about 2-7. The (m)SBSE-TD-GC-MS method showed good linearity (r(2)>0.9913) and high sensitivity (limit of detection: 0.011-0.071 ng mL(-1)) for the test compounds spiked in water. The feasibility and benefit of the method was demonstrated with analysis of odor compounds in roasted green tea. The normalized areas obtained from (m)SBSE showed the best

kW-class diode laser bars

NASA Astrophysics Data System (ADS)

Strohmaier, S. G.; Erbert, G.; Meissner-Schenk, A. H.; Lommel, M.; Schmidt, B.; Kaul, T.; Karow, M.; Crump, P.

2017-02-01

Progress will be presented on ongoing research into the development of ultra-high power and efficiency bars achieving significantly higher output power, conversion efficiency and brightness than currently commercially available. We combine advanced InAlGaAs/GaAs-based epitaxial structures and novel lateral designs, new materials and superior cooling architectures to enable improved performance. Specifically, we present progress in kilowatt-class 10-mm diode laser bars, where recent studies have demonstrated 880 W continuous wave output power from a 10 mm x 4 mm laser diode bar at 850 A of electrical current and 15°C water temperature. This laser achieves < 60% electro-optical efficiency at 880 W CW output power.

Usability engineering: domain analysis activities for augmented-reality systems

NASA Astrophysics Data System (ADS)

Gabbard, Joseph; Swan, J. E., II; Hix, Deborah; Lanzagorta, Marco O.; Livingston, Mark; Brown, Dennis B.; Julier, Simon J.

2002-05-01

This paper discusses our usability engineering process for the Battlefield Augmented Reality System (BARS). Usability engineering is a structured, iterative, stepwise development process. Like the related disciplines of software and systems engineering, usability engineering is a combination of management principals and techniques, formal and semi- formal evaluation techniques, and computerized tools. BARS is an outdoor augmented reality system that displays heads- up battlefield intelligence information to a dismounted warrior. The paper discusses our general usability engineering process. We originally developed the process in the context of virtual reality applications, but in this work we are adapting the procedures to an augmented reality system. The focus of this paper is our work on domain analysis, the first activity of the usability engineering process. We describe our plans for and our progress to date on our domain analysis for BARS. We give results in terms of a specific urban battlefield use case we have designed.

Aerobic exercise training differentially affects ACE C- and N-domain activities in humans: Interactions with ACE I/D polymorphism and association with vascular reactivity.

PubMed

Alves, Cléber Rene; Fernandes, Tiago; Lemos, José Ribeiro; Magalhães, Flávio de Castro; Trombetta, Ivani Credidio; Alves, Guilherme Barreto; Mota, Glória de Fátima Alves da; Dias, Rodrigo Gonçalves; Pereira, Alexandre Costa; Krieger, José Eduardo; Negrão, Carlos Eduardo; Oliveira, Edilamar Menezes

2018-01-01

Previous studies have linked angiotensin-converting enzyme ( ACE) insertion (I)/deletion (D) polymorphism (II, ID and DD) to physical performance. Moreover, ACE has two catalytic domains: NH2 (N) and COOH (C) with distinct functions, and their activity has been found to be modulated by ACE polymorphism. The aim of the present study is to investigate the effects of the interaction between aerobic exercise training (AET) and ACE I/D polymorphism on ACE N- and C-domain activities and vascular reactivity in humans. A total of 315 pre-selected healthy males were genotyped for II, ID and DD genotypes. Fifty completed the full AET (II, n = 12; ID, n = 25; and DD, n = 13), performed in three 90-minute sessions weekly, in the four-month exercise protocol. Pre- and post-training resting heart rate (HR), peak O 2 consumption (VO 2 peak), mean blood pressure (MBP), forearm vascular conduction (FVC), total circulating ACE and C- and N-domain activities were assessed. One-way ANOVA and two -way repeated-measures ANOVA were used. In pre-training, all variables were similar among the three genotypes. In post-training, a similar increase in FVC (35%) was observed in the three genotypes. AET increased VO 2 peak similarly in II, ID and DD (49±2 vs. 57±1; 48±1 vs. 56±3; and 48±5 vs. 58±2 ml/kg/min, respectively). Moreover, there were no changes in HR and MBP. The DD genotype was also associated with greater ACE and C-domain activities at pre- and post-training when compared to II. AET decreased similarly the total ACE and C-domain activities in all genotypes, while increasing the N-domain activity in the II and DD genotypes. However, interestingly, the measurements of N-domain activity after training indicate a greater activity than the other genotypes. These results suggest that the vasodilation in response to AET may be associated with the decrease in total ACE and C-domain activities, regardless of genotype, and that the increase in N-domain activity is dependent on the DD

Acute muscular strength assessment using free weight bars of different thickness.

PubMed

Ratamess, Nicholas A; Faigenbaum, Avery D; Mangine, Gerald T; Hoffman, Jay R; Kang, Jie

2007-02-01

The purpose of the present investigation was to examine strength performance of 6 common resistance training exercises using free weight bars of different thickness. Eleven resistance-trained men (8.2 +/- 2.6 years of experience; age: 22.1 +/- 1.6 years; body mass: 90.5 +/- 8.9 kg) underwent 1 repetition maximum (1RM) strength testing on 6 occasions in random order for the deadlift, bent-over row, upright row, bench press, seated shoulder press, and arm curl exercises under 3 conditions using: (a) a standard Olympic bar (OL), (b) a 2-inch thick bar (5.08 cm grip span), and (c) a 3-inch thick bar (7.62 cm grip span). Significant (p < 0.05) interactions were observed for the "pulling" exercises. For the deadlift and bent-over row, highest 1RM values were obtained with OL, followed by the 2- and 3-inch bar. Significant 1RM performance decrements for the 2- and 3-inch bars were approximately 28.3 and 55.0%, respectively, for the deadlift; decrements for the 2- and 3-inch bars were approximately 8.9 and 37.3%, respectively, for the bent-over row. For the upright row and arm curl, similar 1RMs were obtained for OL and the 2-inch bar. However, a significant performance reduction was observed using the 3-inch bar (approximately 26.1% for the upright row and 17.6% for the arm curl). The reductions in 1RM loads correlated significantly to hand size and maximal isometric grip strength (r = -0.55 to -0.73). No differences were observed between bars for the bench press or shoulder press. In conclusion, the use of 2- and 3-inch thick bars may result in initial weight reductions primarily for pulling exercises presumably due to greater reliance on maximal grip strength and larger hand size.

Effects of Partial and Acute Total Sleep Deprivation on Performance across Cognitive Domains, Individuals and Circadian Phase

PubMed Central

Lo, June C.; Groeger, John A.; Santhi, Nayantara; Arbon, Emma L.; Lazar, Alpar S.; Hasan, Sibah; von Schantz, Malcolm; Archer, Simon N.; Dijk, Derk-Jan

2012-01-01

Background Cognitive performance deteriorates during extended wakefulness and circadian phase misalignment, and some individuals are more affected than others. Whether performance is affected similarly across cognitive domains, or whether cognitive processes involving Executive Functions are more sensitive to sleep and circadian misalignment than Alertness and Sustained Attention, is a matter of debate. Methodology/Principal Findings We conducted a 2 × 12-day laboratory protocol to characterize the interaction of repeated partial and acute total sleep deprivation and circadian phase on performance across seven cognitive domains in 36 individuals (18 males; mean ± SD of age = 27.6±4.0 years). The sample was stratified for the rs57875989 polymorphism in PER3, which confers cognitive susceptibility to total sleep deprivation. We observed a deterioration of performance during both repeated partial and acute total sleep deprivation. Furthermore, prior partial sleep deprivation led to poorer cognitive performance in a subsequent total sleep deprivation period, but its effect was modulated by circadian phase such that it was virtually absent in the evening wake maintenance zone, and most prominent during early morning hours. A significant effect of PER3 genotype was observed for Subjective Alertness during partial sleep deprivation and on n-back tasks with a high executive load when assessed in the morning hours during total sleep deprivation after partial sleep loss. Overall, however, Subjective Alertness and Sustained Attention were more affected by both partial and total sleep deprivation than other cognitive domains and tasks including n-back tasks of Working Memory, even when implemented with a high executive load. Conclusions/Significance Sleep loss has a primary effect on Sleepiness and Sustained Attention with much smaller effects on challenging Working Memory tasks. These findings have implications for understanding how sleep debt and circadian rhythmicity

Biomechanical and Cost Comparisons of Near-Far and Pin-Bar Constructs.

PubMed

Whitney Kluk, Augusta; Zhang, Tina; Russell, Joseph P; Kim, Hyunchul; Hsieh, Adam H; O'Toole, Robert V

2017-03-01

Orthopedic dogma states that external fixator stiffness is improved by placing 1 pin close to the fracture and 1 as distant as possible ("near-far"). This fixator construct is thought to be less expensive than placing pins a shorter distance apart and using "pin-bar" clamps that attach pins to outriggers. The authors therefore hypothesized that the near-far construct is stiffer and less expensive. They compared mechanical stiffness and costs of near-far and pin-bar constructs commonly used for temporary external fixation of femoral shaft fractures. Their testing model simulated femoral shaft fractures in damage control situations. Fourth-generation synthetic femora (n=18) were used. The near-far construct had 2 pins that were 106 mm apart, placed 25 mm from the gap on each side of the fracture. The pin-bar construct pins were 55 mm apart, placed 40 mm from the gap. Mechanical testing was performed on a material test system machine. Stiffness was determined in the linear portion of the load-displacement curve for both constructs in 4 modes: axial compression, torsional loading, frontal plane 3-point bending, and sagittal plane 3-point bending. Costs were determined from a 2012 price guide. Compared with the near-far construct, the pin-bar construct had stiffness increased by 58% in axial compression (P<.05) and by 52% in torsional loading (P<.05). The pin-bar construct increased cost by 11%. In contrast to the authors' hypothesis and existing orthopedic dogma, the near-far construct was less stiff than the pin-bar construct and was similarly priced. Use of the pin-bar construct is mechanically and economically reasonable. [Orthopedics. 2017; 40(2):e238-e241.]. Copyright 2016, SLACK Incorporated.

Crystal structure of the N domain of human somatic angiotensin I-converting enzyme provides a structural basis for domain-specific inhibitor design.

PubMed

Corradi, Hazel R; Schwager, Sylva L U; Nchinda, Aloysius T; Sturrock, Edward D; Acharya, K Ravi

2006-03-31

Human somatic angiotensin I-converting enzyme (sACE) is a key regulator of blood pressure and an important drug target for combating cardiovascular and renal disease. sACE comprises two homologous metallopeptidase domains, N and C, joined by an inter-domain linker. Both domains are capable of cleaving the two hemoregulatory peptides angiotensin I and bradykinin, but differ in their affinities for a range of other substrates and inhibitors. Previously we determined the structure of testis ACE (C domain); here we present the crystal structure of the N domain of sACE (both in the presence and absence of the antihypertensive drug lisinopril) in order to aid the understanding of how these two domains differ in specificity and function. In addition, the structure of most of the inter-domain linker allows us to propose relative domain positions for sACE that may contribute to the domain cooperativity. The structure now provides a platform for the design of "domain-specific" second-generation ACE inhibitors.

Effect of bar cross-section and female housing material on retention of mandibular implant bar overdentures: A comparative in vitro study.

PubMed

Abdel-Khalek, Elsayed A; Ibrahim, Abdullah M

2017-01-01

The aim of this study is to evaluate the effect of different cross-sections of bar connecting two implants on the retention of mandibular overdentures with Hader clip or lined with heat-cured resilient liner as a housing material. The retentive values after simulated 1.5 years of service were also recorded. Edentulous mandibular acrylic model was constructed with two dummy implants located in the canine region and connected with cast bar assembly. According to bar cross-section and anchoring method, four groups ( n = 10) of identical overdentures were used as Hader bar/clip group (HCG), Hader bar/silicone liner female housing group (HSG), oval bar/silicone liner female housing group (OSG), and round bar/silicone liner female housing group (RSG). Each overdenture sample was subjected to simulated wear up to 2740 manual insertions/separations. The mean retentive forces were measured at the baseline and after every 500 insertions. The data were statistically analyzed using one-way analysis of variance. The present study demonstrated that all bar cross-sections showed a significant difference at the baseline ( P < 0.05), but HSG showed greater initial retention compared to HCG, OSG, and RSG. OSG showed a significant higher retention after 2740 insertions (simulated five insertions/day). Within the limitation of this in vitro study and for a similar period of service, heat-cured silicone female housing for Hader bar could maintain greater retention for two-implant-retained overdentures than provided by conventional plastic clip after 1.5 year. The oval bar recorded reasonable initial retention values and maintained these values for 1.5 years of service.

The Carnegie-Irvine Galaxy Survey. V. Statistical Study of Bars and Buckled Bars

NASA Astrophysics Data System (ADS)

Li, Zhao-Yu; Ho, Luis C.; Barth, Aaron J.

2017-08-01

Simulations have shown that bars are subject to a vertical buckling instability that transforms thin bars into boxy or peanut-shaped structures, but the physical conditions necessary for buckling to occur are not fully understood. We use the large sample of local disk galaxies in the Carnegie-Irvine Galaxy Survey to examine the incidence of bars and buckled bars across the Hubble sequence. Depending on the disk inclination angle (I), a buckled bar reveals itself as either a boxy/peanut-shaped bulge (at high I) or as a barlens structure (at low I). We visually identify bars, boxy/peanut-shaped bulges, and barlenses, and examine the dependence of bar and buckled bar fractions on host galaxy properties, including Hubble type, stellar mass, color, and gas mass fraction. We find that the barred and unbarred disks show similar distributions in these physical parameters. The bar fraction is higher (70%-80%) in late-type disks with low stellar mass (M * < 1010.5 M ⊙) and high gas mass ratio. In contrast, the buckled bar fraction increases to 80% toward massive and early-type disks (M * > 1010.5 M ⊙), and decreases with higher gas mass ratio. These results suggest that bars are more difficult to grow in massive disks that are dynamically hotter than low-mass disks. However, once a bar forms, it can easily buckle in the massive disks, where a deeper potential can sustain the vertical resonant orbits. We also find a probable buckling bar candidate (ESO 506-G004) that could provide further clues to understand the timescale of the buckling process.

Structure of the Fibrillin-1 N-Terminal Domains Suggests that Heparan Sulfate Regulates the Early Stages of Microfibril Assembly

PubMed Central

Yadin, David A.; Robertson, Ian B.; McNaught-Davis, Joanne; Evans, Paul; Stoddart, David; Handford, Penny A.; Jensen, Sacha A.; Redfield, Christina

2013-01-01

Summary The human extracellular matrix glycoprotein fibrillin-1 is the primary component of the 10- to 12-nm-diameter microfibrils, which perform key structural and regulatory roles in connective tissues. Relatively little is known about the molecular mechanisms of fibrillin assembly into microfibrils. Studies using recombinant fibrillin fragments indicate that an interaction between the N- and C-terminal regions drives head-to-tail assembly. Here, we present the structure of a fibrillin N-terminal fragment comprising the fibrillin unique N-terminal (FUN) and the first three epidermal growth factor (EGF)-like domains (FUN-EGF3). Two rod-like domain pairs are separated by a short, flexible linker between the EGF1 and EGF2 domains. We also show that the binding site for the C-terminal region spans multiple domains and overlaps with a heparin interaction site. These data suggest that heparan sulfate may sequester fibrillin at the cell surface via FUN-EGF3 prior to aggregation of the C terminus, thereby regulating microfibril assembly. PMID:24035709

Bar Evolution and Bar Properties from Disc Galaxies in the Early Universe

NASA Astrophysics Data System (ADS)

Hutchinson-Smith, Tenley; Simmons, Brooke

2017-01-01

Bars in disc galaxies indicate a large collection of stars in a specific configuration of orbits that give the galaxy center a rectangular looking feature. Astronomers have discovered that these bars affect the distribution of matter in galaxies, and are also related to galaxy stellar mass and star formation history. Little is known about the specifics of how bars evolve and drive the evolution of their host galaxies because only a handful of bars have been studied in detail so far. I have examined a sample of 8,221 barred galaxies from the early universe to identify and examine correlations with galaxy properties. The data comes from Galaxy Zoo, an online citizen science project that allows anyone to classify and measure detailed properties of galaxies. I present results including the fraction of galaxies in the sample that have bars, and the variation of galaxy properties with bar length, including galaxy color and stellar mass. I also compare these results to barred galaxies in the local universe. I will discuss the implications of these results in the context of galaxy evolution overall, including the effect of dark matter on bars and galaxy evolution.

Effect of sodium chloride on the structure and stability of spider silk's N-terminal protein domain.

PubMed

Gronau, Greta; Qin, Zhao; Buehler, Markus J

2013-03-01

A spider's ability to store silk protein solutions at high concentration is believed to be related to the protein's terminal domains. It has been suggested that a shift in salt concentration and pH can have a significant influence on the assembly process. Based on experimental data, a model has been proposed in which the N-terminal domain exists as a monomer during storage and assembles into a homodimer upon spinning. Here we perform a systematic computational study using atomistic, coarse-grained and well-tempered metadynamics simulation to understand how the NaCl concentration in the solution affects the N-terminal domain of the silk protein. Our results show that a high salt concentration, as found during storage, weakens key salt bridges between the monomers, inducing a loss in bond energy by 28.6% in a single salt bridge. As a result dimer formation is less likely as 35.5% less energy is required to unfold the dimer by mechanical force. Conversely, homodimer formation appears to be more likely at low salt concentrations as the salt bridge stays at the lower energy state. The link between salt concentration, structure and stability of the N-terminal domain provides a possible mechanism that prevents premature fiber formation during storage.

ATP Binding to p97/VCP D1 Domain Regulates Selective Recruitment of Adaptors to Its Proximal N-Domain

PubMed Central

Chia, Wei Sheng; Chia, Diana Xueqi; Rao, Feng; Bar Nun, Shoshana; Geifman Shochat, Susana

2012-01-01

p97/Valosin-containing protein (VCP) is a member of the AAA-ATPase family involved in many cellular processes including cell division, intracellular trafficking and extraction of misfolded proteins in endoplasmic reticulum-associated degradation (ERAD). It is a homohexamer with each subunit containing two tandem D1 and D2 ATPase domains and N- and C-terminal regions that function as adaptor protein binding domains. p97/VCP is directed to its many different functional pathways by associating with various adaptor proteins. The regulation of the recruitment of the adaptor proteins remains unclear. Two adaptor proteins, Ufd1/Npl4 and p47, which bind exclusively to the p97/VCP N-domain and direct p97/VCP to either ERAD-related processes or homotypic fusion of Golgi fragments, were studied here. Surface plasmon resonance biosensor-based assays allowed the study of binding kinetics in real time. In competition experiments, it was observed that in the presence of ATP, Ufd1/Npl4 was able to compete more effectively with p47 for binding to p97/VCP. By using non-hydrolysable ATP analogues and the hexameric truncated p97/N-D1 fragment, it was shown that binding rather than hydrolysis of ATP to the proximal D1 domain strengthened the Ufd1/Npl4 association with the N-domain, thus regulating the recruitment of either Ufd1/Npl4 or p47. This novel role of ATP and an assigned function to the D1 AAA-ATPase domain link the multiple functions of p97/VCP to the metabolic status of the cell. PMID:23226521

ATP binding to p97/VCP D1 domain regulates selective recruitment of adaptors to its proximal N-domain.

PubMed

Chia, Wei Sheng; Chia, Diana Xueqi; Rao, Feng; Bar Nun, Shoshana; Geifman Shochat, Susana

2012-01-01

p97/Valosin-containing protein (VCP) is a member of the AAA-ATPase family involved in many cellular processes including cell division, intracellular trafficking and extraction of misfolded proteins in endoplasmic reticulum-associated degradation (ERAD). It is a homohexamer with each subunit containing two tandem D1 and D2 ATPase domains and N- and C-terminal regions that function as adaptor protein binding domains. p97/VCP is directed to its many different functional pathways by associating with various adaptor proteins. The regulation of the recruitment of the adaptor proteins remains unclear. Two adaptor proteins, Ufd1/Npl4 and p47, which bind exclusively to the p97/VCP N-domain and direct p97/VCP to either ERAD-related processes or homotypic fusion of Golgi fragments, were studied here. Surface plasmon resonance biosensor-based assays allowed the study of binding kinetics in real time. In competition experiments, it was observed that in the presence of ATP, Ufd1/Npl4 was able to compete more effectively with p47 for binding to p97/VCP. By using non-hydrolysable ATP analogues and the hexameric truncated p97/N-D1 fragment, it was shown that binding rather than hydrolysis of ATP to the proximal D1 domain strengthened the Ufd1/Npl4 association with the N-domain, thus regulating the recruitment of either Ufd1/Npl4 or p47. This novel role of ATP and an assigned function to the D1 AAA-ATPase domain link the multiple functions of p97/VCP to the metabolic status of the cell.

The Carnegie-Irvine Galaxy Survey. V. Statistical Study of Bars and Buckled Bars

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Zhao-Yu; Ho, Luis C.; Barth, Aaron J., E-mail: lizy@shao.ac.cn

Simulations have shown that bars are subject to a vertical buckling instability that transforms thin bars into boxy or peanut-shaped structures, but the physical conditions necessary for buckling to occur are not fully understood. We use the large sample of local disk galaxies in the Carnegie-Irvine Galaxy Survey to examine the incidence of bars and buckled bars across the Hubble sequence. Depending on the disk inclination angle ( i ), a buckled bar reveals itself as either a boxy/peanut-shaped bulge (at high i ) or as a barlens structure (at low i ). We visually identify bars, boxy/peanut-shaped bulges, andmore » barlenses, and examine the dependence of bar and buckled bar fractions on host galaxy properties, including Hubble type, stellar mass, color, and gas mass fraction. We find that the barred and unbarred disks show similar distributions in these physical parameters. The bar fraction is higher (70%–80%) in late-type disks with low stellar mass ( M {sub *} < 10{sup 10.5} M {sub ⊙}) and high gas mass ratio. In contrast, the buckled bar fraction increases to 80% toward massive and early-type disks ( M {sub *} > 10{sup 10.5} M {sub ⊙}), and decreases with higher gas mass ratio. These results suggest that bars are more difficult to grow in massive disks that are dynamically hotter than low-mass disks. However, once a bar forms, it can easily buckle in the massive disks, where a deeper potential can sustain the vertical resonant orbits. We also find a probable buckling bar candidate (ESO 506−G004) that could provide further clues to understand the timescale of the buckling process.« less

Speculations on the dynamics of Jupiter's atmosphere from 1 to 100 bars

NASA Astrophysics Data System (ADS)

Ingersoll, A. P.

2017-12-01

The latitude-altitude map of ammonia mixing ratio shows an ammonia-rich zone at 0-5°N, with mixing ratios of 320-340 ppm, extending from 40-60 bars up to the ammonia cloud base at 0.7 bars. Ammonia-poor air occupies a belt from 5-20°N. We argue that downdrafts as well as updrafts are needed in the 0-5°N zone to balance the upward ammonia flux. Outside the 0-20°N region, the belt-zone signature is weaker. At latitudes out to ±40°, there is an ammonia-rich layer from cloud base down to 2 bars which we argue is caused by falling precipitation. Below, there is an ammonia-poor layer with a minimum at 6 bars. Unanswered questions include how the ammonia-poor layer is maintained, why the belt-zone structure is barely evident in the ammonia distribution outside 0-20°N, and how the internal heat is transported through the ammonia-poor layer to the ammonia cloud base. Here we speculate on possible answers, including double-diffusive convection, deep abyssal overturning, and mass loading of heavy condensates in a hydrogen/helium atmosphere. Ingersoll, A. P. et al. (2017). Implications of the ammonia distribution on Jupiter from 1 to 100 bars as measured by the Juno microwave radiometer. Geophys. Res. Lett., in press, doi: 10.1002/2017GL074277.

A Note on a Sampling Theorem for Functions over GF(q)n Domain

NASA Astrophysics Data System (ADS)

Ukita, Yoshifumi; Saito, Tomohiko; Matsushima, Toshiyasu; Hirasawa, Shigeichi

In digital signal processing, the sampling theorem states that any real valued function ƒ can be reconstructed from a sequence of values of ƒ that are discretely sampled with a frequency at least twice as high as the maximum frequency of the spectrum of ƒ. This theorem can also be applied to functions over finite domain. Then, the range of frequencies of ƒ can be expressed in more detail by using a bounded set instead of the maximum frequency. A function whose range of frequencies is confined to a bounded set is referred to as bandlimited function. And a sampling theorem for bandlimited functions over Boolean domain has been obtained. Here, it is important to obtain a sampling theorem for bandlimited functions not only over Boolean domain (GF(q)n domain) but also over GF(q)n domain, where q is a prime power and GF(q) is Galois field of order q. For example, in experimental designs, although the model can be expressed as a linear combination of the Fourier basis functions and the levels of each factor can be represented by GF(q)n, the number of levels often take a value greater than two. However, the sampling theorem for bandlimited functions over GF(q)n domain has not been obtained. On the other hand, the sampling points are closely related to the codewords of a linear code. However, the relation between the parity check matrix of a linear code and any distinct error vectors has not been obtained, although it is necessary for understanding the meaning of the sampling theorem for bandlimited functions. In this paper, we generalize the sampling theorem for bandlimited functions over Boolean domain to a sampling theorem for bandlimited functions over GF(q)n domain. We also present a theorem for the relation between the parity check matrix of a linear code and any distinct error vectors. Lastly, we clarify the relation between the sampling theorem for functions over GF(q)n domain and linear codes.

Performance Assessment in CTE: Focusing on the Cognitive, Psychomotor ...and Affective Domains

ERIC Educational Resources Information Center

Washer, Bart; Cochran, Lori

2012-01-01

When a student is performing in the psychomotor domain, the authors believe the student is also performing in the cognitive domain (sequencing steps, evaluating the situation) and in the affective domain (appreciating a job well done, quality control, safety). As Dabney Doty, former instructor at the University of Central Missouri, stated, "There…

The TDP-43 N-terminal domain structure at high resolution.

PubMed

Mompeán, Miguel; Romano, Valentina; Pantoja-Uceda, David; Stuani, Cristiana; Baralle, Francisco E; Buratti, Emanuele; Laurents, Douglas V

2016-04-01

Transactive response DNA-binding protein 43 kDa (TDP-43) is an RNA transporting and processing protein whose aberrant aggregates are implicated in neurodegenerative diseases. The C-terminal domain of this protein plays a key role in mediating this process. However, the N-terminal domain (residues 1-77) is needed to effectively recruit TDP-43 monomers into this aggregate. In the present study, we report, for the first time, the essentially complete (1) H, (15) N and (13) C NMR assignments and the structure of the N-terminal domain determined on the basis of 26 hydrogen-bond, 60 torsion angle and 1058 unambiguous NOE structural restraints. The structure consists of an α-helix and six β-strands. Two β-strands form a β-hairpin not seen in the ubiquitin fold. All Pro residues are in the trans conformer and the two Cys are reduced and distantly separated on the surface of the protein. The domain has a well defined hydrophobic core composed of F35, Y43, W68, Y73 and 17 aliphatic side chains. The fold is topologically similar to the reported structure of axin 1. The protein is stable and no denatured species are observed at pH 4 and 25 °C. At 4 kcal·mol(-1) , the conformational stability of the domain, as measured by hydrogen/deuterium exchange, is comparable to ubiquitin (6 kcal·mol(-1) ). The β-strands, α-helix, and three of four turns are generally rigid, although the loop formed by residues 47-53 is mobile, as determined by model-free analysis of the (15) N{(1) H}NOE, as well as the translational and transversal relaxation rates. Structural data have been deposited in the Protein Data Bank under accession code: 2n4p. The NMR assignments have been deposited in the BMRB database under access code: 25675. © 2016 Federation of European Biochemical Societies.

Performance in hippocampus- and PFC-dependent cognitive domains are not concomitantly impaired in rats exposed to 20 cGy of 1 GeV/n 56Fe particles

NASA Astrophysics Data System (ADS)

Britten, Richard A.; Miller, Vania D.; Hadley, Melissa M.; Jewell, Jessica S.; Macadat, Evangeline

2016-08-01

NASA is currently conducting ground based experiments to determine whether the radiation environment that astronauts will encounter on deep space missions will have an impact on their long-term health and their ability to complete the various tasks during the mission. Emerging data suggest that exposure of rodents to mission-relevant HZE radiation doses does result in the impairment of various neurocognitive processes. An essential part of mission planning is a probabilistic risk assessment process that takes into account the likely incidence and severity of a problem. To date few studies have reported the impact of space radiation in a format that is amenable to PRA, and those that have only reported data for a single cognitive process. This study has established the ability of individual male Wistar rats to conduct a hippocampus-dependent (spatial memory) task and a cortex-dependent (attentional set shifting task) 90 days after exposure to 20 cGy 1 GeV/n 56Fe particles. Radiation-induced impairment of performance in one cognitive domain was not consistently associated with impaired performance in the other domain. Thus sole reliance upon a single measure of cognitive performance may substantially under-estimate the risk of cognitive impairment, and ultimately it may be necessary to establish the likelihood that mission-relevant HZE doses will impair performance in the three or four cognitive domains that NASA considers to be most critical for mission success, and build a PRA using the composite data from such studies.

Membrane interaction of the N-terminal domain of chemokine receptor CXCR1.

PubMed

Haldar, Sourav; Raghuraman, H; Namani, Trishool; Rajarathnam, Krishna; Chattopadhyay, Amitabha

2010-06-01

The N-terminal domain of chemokine receptors constitutes one of the two critical ligand binding sites, and plays important roles by mediating binding affinity, receptor selectivity, and regulating function. In this work, we monitored the organization and dynamics of a 34-mer peptide of the CXC chemokine receptor 1 (CXCR1) N-terminal domain and its interaction with membranes by utilizing a combination of fluorescence-based approaches and surface pressure measurements. Our results show that the CXCR1 N-domain 34-mer peptide binds vesicles of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and upon binding, the tryptophan residues of the peptide experience motional restriction and exhibit red edge excitation shift (REES) of 19nm. These results are further supported by increase in fluorescence anisotropy and mean fluorescence lifetime upon membrane binding. These results constitute one of the first reports demonstrating membrane interaction of the N-terminal domain of CXCR1 and gain relevance in the context of the emerging role of cellular membranes in chemokine signaling.

Finite Element Analysis of IPS Empress II Ceramic Bridge Reinforced by Zirconia Bar

PubMed Central

Kermanshah, H.; Bitaraf, T.; Geramy, A.

2012-01-01

Objective: The aim of this study was to determine the effect of trenched zirconia bar on the von Mises stress distribution of IPS –Empress II core ceramics. Materials and Methods: The three-dimensional model including a three-unit bridge from the second premolar to the second molar was designed. The model was reinforced with zirconia bar (ZB), zirconia bar with vertical trench (VZB) and zirconia bar with horizontal trench (HZB) (cross sections of these bars were circular). The model without zirconia bar was designed as the control. The bridges were loaded by 200 N and 500 N on the occlusal surface at the middle of the pontic component and von Mises stresses were evaluated along a defined path. Results: In the connector area, von Mises stress in MPa were approximately identical in the specimens with ZB (at molar connector (MC): 4.75 and at premolar connector (PC): 6.40) and without ZB (MC: 5.50, PC: 6.68), and considerable differences were not recognized. Whereas, Von-Mises stress (MPa) in the specimens with horizontal trenched Zirconia bar (HZB) (MC: 3.91, PC: 2.44) and Vertical trenched Zirconia bar (VZB) (MC: 2.53, PC: 2.56) was decreased considerably. Conclusion: Embeded trenched zirconia bar could reinforce IPS-Empress II at the connector area which is a main failure region in all ceramic fixed partial dentures. PMID:23323181

Finite Element Analysis of IPS Empress II Ceramic Bridge Reinforced by Zirconia Bar.

PubMed

Kermanshah, H; Bitaraf, T; Geramy, A

2012-01-01

The aim of this study was to determine the effect of trenched zirconia bar on the von Mises stress distribution of IPS -Empress II core ceramics. The three-dimensional model including a three-unit bridge from the second premolar to the second molar was designed. The model was reinforced with zirconia bar (ZB), zirconia bar with vertical trench (VZB) and zirconia bar with horizontal trench (HZB) (cross sections of these bars were circular). The model without zirconia bar was designed as the control. The bridges were loaded by 200 N and 500 N on the occlusal surface at the middle of the pontic component and von Mises stresses were evaluated along a defined path. IN THE CONNECTOR AREA, VON MISES STRESS IN MPA WERE APPROXIMATELY IDENTICAL IN THE SPECIMENS WITH ZB (AT MOLAR CONNECTOR (MC): 4.75 and at premolar connector (PC): 6.40) and without ZB (MC: 5.50, PC: 6.68), and considerable differences were not recognized. Whereas, Von-Mises stress (MPa) in the specimens with horizontal trenched Zirconia bar (HZB) (MC: 3.91, PC: 2.44) and Vertical trenched Zirconia bar (VZB) (MC: 2.53, PC: 2.56) was decreased considerably. Embeded trenched zirconia bar could reinforce IPS-Empress II at the connector area which is a main failure region in all ceramic fixed partial dentures.

Discrete and Structurally Unique Proteins (T$$\\bar{a}$$pirins) Mediate Attachment of Extremely Thermophilic Caldicellulosiruptor Species to Cellulose

DOE PAGES

Blumer-Schuette, S. E.; Alahuhta, M.; Conway, J. M.; ...

2015-04-24

A variety of catalytic and noncatalytic protein domains are deployed by select microorganisms to deconstruct lignocellulose. These extracellular proteins are used to attach to, modify, and hydrolyze the complex polysaccharides present in plant cell walls. Cellulolytic enzymes, often containing carbohydrate-binding modules, are key to this process; however, these enzymes are not solely responsible for attachment. Few mechanisms of attachment have been discovered among bacteria that do not form large polypeptide structures, called cellulosomes, to deconstruct biomass. In this study, bioinformatics and proteomics analyses identified unique, discrete, hypothetical proteins (“tmore » $$\\bar{a}$$pirins,” origin from M$$\\bar{a}$$ori: to join), not directly associated with cellulases, that mediate attachment to cellulose by species in the noncellulosomal, extremely thermophilic bacterial genus Caldicellulosiruptor. Two t$$\\bar{a}$$pirin genes are located directly downstream of a type IV pilus operon in strongly cellulolytic members of the genus, whereas homologs are absent from the weakly cellulolytic Caldicellulosiruptor species. Based on their amino acid sequence, t$$\\bar{a}$$pirins are specific to these extreme thermophiles. T$$\\bar{a}$$pirins are also unusual in that they share no detectable protein domain signatures with known polysaccharide-binding proteins. Adsorption isotherm and trans vivo analyses demonstrated the carbohydrate-binding module-like affinity of the t$$\\bar{a}$$pirins for cellulose. Crystallization of a cellulose-binding truncation from one t$$\\bar{a}$$pirin indicated that these proteins form a long β-helix core with a shielded hydrophobic face. In addition, they are structurally unique and define a new class of polysaccharide adhesins. Strongly cellulolytic Caldicellulosiruptor species employ t$$\\bar{a}$$pirins to complement substrate-binding proteins from the ATP-binding cassette transporters and multidomain extracellular and S

Discrete and Structurally Unique Proteins (T$$\\bar{a}$$pirins) Mediate Attachment of Extremely Thermophilic Caldicellulosiruptor Species to Cellulose

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blumer-Schuette, S. E.; Alahuhta, M.; Conway, J. M.

A variety of catalytic and noncatalytic protein domains are deployed by select microorganisms to deconstruct lignocellulose. These extracellular proteins are used to attach to, modify, and hydrolyze the complex polysaccharides present in plant cell walls. Cellulolytic enzymes, often containing carbohydrate-binding modules, are key to this process; however, these enzymes are not solely responsible for attachment. Few mechanisms of attachment have been discovered among bacteria that do not form large polypeptide structures, called cellulosomes, to deconstruct biomass. In this study, bioinformatics and proteomics analyses identified unique, discrete, hypothetical proteins (“tmore » $$\\bar{a}$$pirins,” origin from M$$\\bar{a}$$ori: to join), not directly associated with cellulases, that mediate attachment to cellulose by species in the noncellulosomal, extremely thermophilic bacterial genus Caldicellulosiruptor. Two t$$\\bar{a}$$pirin genes are located directly downstream of a type IV pilus operon in strongly cellulolytic members of the genus, whereas homologs are absent from the weakly cellulolytic Caldicellulosiruptor species. Based on their amino acid sequence, t$$\\bar{a}$$pirins are specific to these extreme thermophiles. T$$\\bar{a}$$pirins are also unusual in that they share no detectable protein domain signatures with known polysaccharide-binding proteins. Adsorption isotherm and trans vivo analyses demonstrated the carbohydrate-binding module-like affinity of the t$$\\bar{a}$$pirins for cellulose. Crystallization of a cellulose-binding truncation from one t$$\\bar{a}$$pirin indicated that these proteins form a long β-helix core with a shielded hydrophobic face. In addition, they are structurally unique and define a new class of polysaccharide adhesins. Strongly cellulolytic Caldicellulosiruptor species employ t$$\\bar{a}$$pirins to complement substrate-binding proteins from the ATP-binding cassette transporters and multidomain extracellular and S

Directed evolution of the TALE N-terminal domain for recognition of all 5' bases.

PubMed

Lamb, Brian M; Mercer, Andrew C; Barbas, Carlos F

2013-11-01

Transcription activator-like effector (TALE) proteins can be designed to bind virtually any DNA sequence. General guidelines for design of TALE DNA-binding domains suggest that the 5'-most base of the DNA sequence bound by the TALE (the N0 base) should be a thymine. We quantified the N0 requirement by analysis of the activities of TALE transcription factors (TALE-TF), TALE recombinases (TALE-R) and TALE nucleases (TALENs) with each DNA base at this position. In the absence of a 5' T, we observed decreases in TALE activity up to >1000-fold in TALE-TF activity, up to 100-fold in TALE-R activity and up to 10-fold reduction in TALEN activity compared with target sequences containing a 5' T. To develop TALE architectures that recognize all possible N0 bases, we used structure-guided library design coupled with TALE-R activity selections to evolve novel TALE N-terminal domains to accommodate any N0 base. A G-selective domain and broadly reactive domains were isolated and characterized. The engineered TALE domains selected in the TALE-R format demonstrated modularity and were active in TALE-TF and TALEN architectures. Evolved N-terminal domains provide effective and unconstrained TALE-based targeting of any DNA sequence as TALE binding proteins and designer enzymes.

Cathode Characterization with Steel and Copper Collector Bars in an Electrolytic Cell

NASA Astrophysics Data System (ADS)

Das, Subrat; Morsi, Yos; Brooks, Geoffrey

2013-12-01

This article presents finite-element method simulation results of current distribution in an aluminum electrolytic cell. The model uses one quarter of the cell as a computational domain assuming longitudinal (along the length of the cell) and transverse axes of symmetries. The purpose of this work is to closely examine the impact of steel and copper collector bars on the cell current distribution. The findings indicated that an inclined steel collector bar (φ = 1°) can save up to 10-12 mV from the cathode lining in comparison to a horizontal 100 mm × 150-mm steel collector bar. It is predicted that a copper collector bar has a much higher potential of saving cathode voltage drop (CVD) and has a greater impact on the overall current distribution in the cell. A copper collector bar with 72% of cathode length and size of 100 mm × 150 mm is predicted to have more than 150 mV savings in cathode lining. In addition, a significant improvement in current distribution over the entire cathode surface is achieved when compared with a similar size of steel collector bar. There is a reduction of more than 70% in peak current density value due to the higher conductivity of copper. Comparisons between steel and copper collector bars with different sizes are discussed in terms CVD and current density distribution. The most important aspect of the findings is to recognize the influence of copper collector bars on the current distribution in molten metal. Lorentz fields are evaluated at different sizes of steel and copper collector bars. The simulation predicts that there is 50% decrease in Lorentz force due to the improvement in current distribution in the molten metal.

The structure of the nucleoprotein binding domain of lyssavirus phosphoprotein reveals a structural relationship between the N-RNA binding domains of Rhabdoviridae and Paramyxoviridae.

PubMed

Delmas, Olivier; Assenberg, Rene; Grimes, Jonathan M; Bourhy, Hervé

2010-01-01

The phosphoprotein P of non-segmented negative-sense RNA viruses is an essential component of the replication and transcription complex and acts as a co-factor for the viral RNA-dependent RNA polymerase. P recruits the viral polymerase to the nucleoprotein-bound viral RNA (N-RNA) via an interaction between its C-terminal domain and the N-RNA complex. We have obtained the structure of the C-terminal domain of P of Mokola virus (MOKV), a lyssavirus that belongs to the Rhabdoviridae family and mapped at the amino acid level the crucial positions involved in interaction with N and in the formation of the viral replication complex. Comparison of the N-RNA binding domains of P solved to date suggests that the N-RNA binding domains are structurally conserved among paramyxoviruses and rhabdoviruses in spite of low sequence conservation. We also review the numerous other functions of this domain and more generally of the phosphoprotein.

College students' exposure to tobacco marketing in nightclubs and bars.

PubMed

Ridner, S Lee; Myers, John A; Hahn, Ellen J; Ciszewski, Tiffany N

2010-01-01

to examine whether a college student's exposure to tobacco marketing in nightclubs and bars was affected by the presence of a smoke-free law. a random sample (N = 478) of students participated in the survey (no smoke-free law, n = 240; smoke-free law, n = 238). The analysis was limited to students who reported being in nightclubs and bars (n = 171). a nonexperimental, cross-sectional, 2-group design was used. students in the smoke-free law city were more likely to be approached by tobacco marketers (34.7% versus 20.2%, p = .02), offered free gifts (41.7% versus 24.2%, p = .02), and take free gifts for themselves (34.7% versus 19.2%, p = .02). They were more likely to be exposed to direct marketing strategies (1.83 versus 1.12, p = .02). There was no difference on indirect tobacco marketing by site. tobacco marketing is pervasive in nightclubs and bars. Smoke-free laws may protect against exposure to secondhand smoke but not the "pro" smoking messages students encounter.

Studying W‧ boson contributions in \\bar{B} \\rightarrow {D}^{(* )}{{\\ell }}^{-}{\\bar{\

NASA Astrophysics Data System (ADS)

Wang, Yi-Long; Wei, Bin; Sheng, Jin-Huan; Wang, Ru-Min; Yang, Ya-Dong

2018-05-01

Recently, the Belle collaboration reported the first measurement of the τ lepton polarization P τ (D*) in \\bar{B}\\to {D}* {τ }-{\\bar{ν }}τ decay and a new measurement of the rate of the branching ratios R(D*), which are consistent with the Standard Model (SM) predictions. These could be used to constrain the New Physics (NP) beyond the SM. In this paper, we probe \\bar{B}\\to {D}(* ){{\\ell }}-{\\bar{ν }}{\\ell } (ℓ = e, μ, τ) decays in the model-independent way and in the specific G(221) models with lepton flavour universality. Considering the theoretical uncertainties and the experimental errors at the 95% C.L., we obtain the quite strong bounds on the model-independent parameters {C}{{LL}}{\\prime },{C}{{LR}}{\\prime },{C}{{RR}}{\\prime },{C}{{RL}}{\\prime },{g}V,{g}A,{g}V{\\prime },{g}A{\\prime } and the specific G(221) model parameter rates. We find that the constrained NP couplings have no obvious effects on all (differential) branching ratios and their rates, nevertheless, many NP couplings have very large effects on the lepton spin asymmetries of \\bar{B}\\to {D}(* ){{\\ell }}-{\\bar{ν }}{\\ell } decays and the forward–backward asymmetries of \\bar{B}\\to {D}* {{\\ell }}-{\\bar{ν }}{\\ell }. So we expect precision measurements of these observables would be researched by LHCb and Belle-II.

Universal precision sine bar attachment

NASA Technical Reports Server (NTRS)

Mann, Franklin D. (Inventor)

1989-01-01

This invention relates to an attachment for a sine bar which can be used to perform measurements during lathe operations or other types of machining operations. The attachment can be used for setting precision angles on vises, dividing heads, rotary tables and angle plates. It can also be used in the inspection of machined parts, when close tolerances are required, and in the layout of precision hardware. The novelty of the invention is believed to reside in a specific versatile sine bar attachment for measuring a variety of angles on a number of different types of equipment.

Multi-wavelength observations of barred, flocculent galaxies

NASA Astrophysics Data System (ADS)

Ratay, Douglas Lee

Although it is generally accepted that large galaxies form through the assemblage of smaller objects, an explanation for the morphology of galaxies is not available. Any complete theory of galaxy morphology must include production and dissolution mechanisms for galactic bars, rings, nuclear bars, spiral arms, and companions. This theory does not exist because of the lack of detailed data from many types of galaxies in different environments. We have defined a new sample of galaxies which are simultaneously flocculent, barred, and isolated. We have performed optical, near-infrared, and radio (HI) observations of the galaxies in this sample. We measured properties of our galaxies including bar length, bar axis ratio, HI diameter, HI mass, and dynamical mass. We found that our sample group is heterogeneous, and compares well to a standard samples of galaxies. We found two of our galaxies to possess companions, and two others to show evidence of current interactions. This is consistent with other observations indicating that local isolated galaxies do not possess a large number of small companions. We cannot rule out the possibility of very small companions. We find that as a group our sample is slightly less luminous than normal galaxies and may be more likely to be involved in interactions. We conclude that the bar and spiral arm features in our sample are due to processes internal to the galaxies, likely involving the interaction between the galactic disk and halo. We defined a control sample of barred, grand design galaxies to further determine the acceptability of barred, flocculent galaxies as a physically meaningful subset of galaxies.

Determination of Phenols Isomers in Water by Novel Nanosilica/Polydimethylsiloxane-Coated Stirring Bar Combined with High Performance Liquid Chromatography-Fourier Transform Infrared Spectroscopy.

PubMed

Zheng, Bei; Li, Wentao; Liu, Lin; Wang, Xin; Chen, Chen; Yu, Zhiyong; Li, Hongyan

2017-08-18

A novel nanosilica/polydimethylsiloxane (SiO 2 /PDMS) coated stirring bar was adopted in the sorption extraction (SBSE) of phenols in water, and the high performance liquid chromatography-fourier transform infrared spectroscopy (HPLC-FTIR) was subsequently used to determination of phenol concentration. The SiO 2 /PDMS coating was prepared by sol-gel method and characterized with respect to morphology and specific surface area. The results of field-emission scanning electron microscope (FE-SEM) and N 2 adsorption-desorption as well as phenol adsorption experiments denoted that SiO 2 /PDMS has larger surface area and better adsorption capacity than commercial PDMS. The extraction efficiency of phenol with SiO 2 /PDMS coated stirring bar was optimized in terms of ion strength, flow rate of phenol-involved influent, type of desorption solvent and desorption time. More than 75% of phenol desorption efficiency could be kept even after 50 cycles of extraction, indicating the high stability of the SiO 2 /PDMS coated stirring bar. Approximately 0.16 mg/L 2, 5-dimethylphenol (2, 5-DMP), which was 34-fold more toxic than phenol, was detected in water through HPLC-FTIR. However, 2, 5-DMP could be oxidized to 5-methy-2-hydroxy benzaldehyde after disinfection in drinking water treatment process. Therefore, the proposed method of SiO 2 /PDMS-SBSE-HPLC-FTIR is successfully applied in the analysis of phenols isomers in aqueous environment.

Aerobic exercise training differentially affects ACE C- and N-domain activities in humans: Interactions with ACE I/D polymorphism and association with vascular reactivity

PubMed Central

Alves, Cléber Rene; Fernandes, Tiago; Lemos, José Ribeiro; Magalhães, Flávio de Castro; Trombetta, Ivani Credidio; Alves, Guilherme Barreto; da Mota, Glória de Fátima Alves; Dias, Rodrigo Gonçalves; Pereira, Alexandre Costa; Krieger, José Eduardo; Negrão, Carlos Eduardo; Oliveira, Edilamar Menezes

2018-01-01

Introduction: Previous studies have linked angiotensin-converting enzyme (ACE) insertion (I)/deletion (D) polymorphism (II, ID and DD) to physical performance. Moreover, ACE has two catalytic domains: NH2 (N) and COOH (C) with distinct functions, and their activity has been found to be modulated by ACE polymorphism. The aim of the present study is to investigate the effects of the interaction between aerobic exercise training (AET) and ACE I/D polymorphism on ACE N- and C-domain activities and vascular reactivity in humans. Materials and methods: A total of 315 pre-selected healthy males were genotyped for II, ID and DD genotypes. Fifty completed the full AET (II, n = 12; ID, n = 25; and DD, n = 13), performed in three 90-minute sessions weekly, in the four-month exercise protocol. Pre- and post-training resting heart rate (HR), peak O2 consumption (VO2 peak), mean blood pressure (MBP), forearm vascular conduction (FVC), total circulating ACE and C- and N-domain activities were assessed. One-way ANOVA and two-way repeated-measures ANOVA were used. Results: In pre-training, all variables were similar among the three genotypes. In post-training, a similar increase in FVC (35%) was observed in the three genotypes. AET increased VO2 peak similarly in II, ID and DD (49±2 vs. 57±1; 48±1 vs. 56±3; and 48±5 vs. 58±2 ml/kg/min, respectively). Moreover, there were no changes in HR and MBP. The DD genotype was also associated with greater ACE and C-domain activities at pre- and post-training when compared to II. AET decreased similarly the total ACE and C-domain activities in all genotypes, while increasing the N-domain activity in the II and DD genotypes. However, interestingly, the measurements of N-domain activity after training indicate a greater activity than the other genotypes. These results suggest that the vasodilation in response to AET may be associated with the decrease in total ACE and C-domain activities, regardless of genotype, and that the increase in N-domain

Greater gains from smoke-free legislation for non-smoking bar staff in Belfast.

PubMed

Bannon, Finian; Devlin, Anne; McElwee, Gerry; Gavin, Anna

2009-12-01

In April 2007, smoke-free legislation was enacted in workplaces throughout N. Ireland. The effects of this legislation on bar workers' health and their exposure to second-hand smoke at home, work and social environment, and their attitudes to the legislation before and after its implementation remain to be documented. A self-completed questionnaire of bar staff in 35 Belfast bars, before (March 2007, n = 110) and after the legislation (July 2007, n = 110). Smokers (excluding 'social smokers') made up 41.6% of respondents. After the introduction of the smoke-free legislation, the reductions in the proportion of bar workers reporting various respiratory symptoms ranged from 1.3% to 18.6% for smokers and from 21.9% to 33.2% for non-smokers. Likewise, the reductions for various sensory symptoms ranged from 7.3% to 17.7% for smokers and from 29.6% to 46.8% for non-smokers. Reduction in wheeze, cough and throat symptoms after the legislation were much greater for non-smokers than smokers. The proportion of bar staff who reported satisfaction with the legislation remained unchanged across the surveys. Decreases in perceived exposure to second-hand smoke occurred at work, home and in social settings. After the legislation's enactment, a majority of bar workers felt the workplace was healthier (98%). These first findings show reduced reported symptoms among bar workers, both smokers and non-smokers, after the introduction of smoke-free legislation in N. Ireland, though greater among non-smokers. There was also a reported fall in the hours of second-hand smoke exposure in the home for this group of workers which has a high prevalence of smokers.

Study of aging and embrittlement of microalloyed steel bars

NASA Astrophysics Data System (ADS)

Campillo, B.; Perez, R.; Martinez, L.

1996-10-01

The aging of hooks, anchors, and other bent reinforcing steel bars in concrete structures are considered in modern international standards. Rebend test procedures have been designed in order to predict the aging embrittlement susceptibility by submerging bent reinforcing bar specimens in boiling water. Subsequently the bars are rebent or straightened in order to determine the loss of ductility or embrittlement of the aged material. The present work considers the influence of carbon, sulfur, and niobium on the performance of reinforcing bars in rebend tests of 300 heats of microalloyed steel bars with a variety of compositions. The microstructural evidence and the statistical results clearly indicate the strong influence of carbon and sulfur on rebend failure, while niobium-rich precipitates contribute to the hardening of the ferrite grains during aging.

General and Domain-Specific Contributions to Creative Ideation and Creative Performance

PubMed Central

An, Donggun; Runco, Mark A.

2016-01-01

The general objective of this study was to reexamine two views of creativity, one positing that there is a general creative capacity or talent and the other that creativity is domain-specific. These two views were compared by (a) testing correlations among measures of domain-general and domain-specific creativity and (b) examining how the general and the specific measures was each related to indices of knowledge, motivation, and personality. Participants were 147 college students enrolled in a foreign language course. Data were collected on participants’ domain knowledge, motivation, and creative personality, as well as four measures representing “General or Domain-Specific Creative Ideation” or “Creative Performance and Activity”. Results indicated that the four measures of creativity were correlated with one another, except for “General Performance and Activity” and “Domain-Specific Ideation.” A canonical correlation indicated that knowledge, motivation, and personality were significantly correlated with the four creativity measures (Rc = .49, p < .01). Multiple regressions uncovered particular relationships consistent with the view that creativity has both general and domain-specific contributions. Limitations, such as the focus on one domain, and future directions are discussed. PMID:27872664

Nutritional Evaluation of NASA's Rodent Food Bar Diet

NASA Technical Reports Server (NTRS)

Barrett, Joyce E.; Yu, Diane S.; Dalton, Bonnie P.

2000-01-01

Tests are being conducted on NASA's rodent Food Bar in preparation for long-term use as the rat and mouse diet aboard the International Space Station. Nutritional analyses are performed after the bars are manufactured and then repeated periodically to determine nutritional stability. The primary factors analyzed are protein, ash, fat, fiber, moisture, amino acids, fatty acids, and minerals. Nutrient levels are compared to values published in the National Research Council's dietary requirements for rodents, and also to those contained in several commonly used commercial rodent lab diets. The Food Bar is manufactured from a powdered diet to which moisture is added as it is processed through an extruder. The bars are dipped into potassium sorbate, vacuum-sealed, and irradiated. In order to determine nutrient changes during extrusion and irradiation, the powdered diet, the non-irradiated bars, and the irradiated bars are all analyzed. We have observed lower values for some nutrients (iodine, vitamin K, and iron) in the Food Bars compared with NRC requirements. Many nutrients in the Food Bars are contained at a higher level than levels in the NRC requirements. An additional factor we are investigating is the 26% moisture level in the Food Bars, which drops to about 15% within a week, compared to a stable 10% moisture in many standard lab chow diets. In addition to the nutritional analyses, the food bar is being fed to several strains of rats and mice, and feeding study and necropsy results are being observed (Barrett et al, unpublished data). Information from the nutritional analyses and from the rodent studies will enable us to recommend the formulation that will most adequately meet the rodent Food Bar requirements for long-term use aboard the Space Station.

The N domain of somatic angiotensin-converting enzyme negatively regulates ectodomain shedding and catalytic activity.

PubMed

Woodman, Zenda L; Schwager, Sylva L U; Redelinghuys, Pierre; Carmona, Adriana K; Ehlers, Mario R W; Sturrock, Edward D

2005-08-01

sACE (somatic angiotensin-converting enzyme) consists of two homologous, N and C domains, whereas the testis isoenzyme [tACE (testis ACE)] consists of a single C domain. Both isoenzymes are shed from the cell surface by a sheddase activity, although sACE is shed much less efficiently than tACE. We hypothesize that the N domain of sACE plays a regulatory role, by occluding a recognition motif on the C domain required for ectodomain shedding and by influencing the catalytic efficiency. To test this, we constructed two mutants: CNdom-ACE and CCdom-ACE. CNdom-ACE was shed less efficiently than sACE, whereas CCdom-ACE was shed as efficiently as tACE. Notably, cleavage occurred both within the stalk and the interdomain bridge in both mutants, suggesting that a sheddase recognition motif resides within the C domain and is capable of directly cleaving at both positions. Analysis of the catalytic properties of the mutants and comparison with sACE and tACE revealed that the k(cat) for sACE and CNdom-ACE was less than or equal to the sum of the kcat values for tACE and the N-domain, suggesting negative co-operativity, whereas the kcat value for the CCdom-ACE suggested positive co-operativity between the two domains. Taken together, the results provide support for (i) the existence of a sheddase recognition motif in the C domain and (ii) molecular flexibility of the N and C domains in sACE, resulting in occlusion of the C-domain recognition motif by the N domain as well as close contact of the two domains during hydrolysis of peptide substrates.

The N domain of somatic angiotensin-converting enzyme negatively regulates ectodomain shedding and catalytic activity

PubMed Central

Woodman, Zenda L.; Schwager, Sylva L. U.; Redelinghuys, Pierre; Carmona, Adriana K.; Ehlers, Mario R. W.; Sturrock, Edward D.

2005-01-01

sACE (somatic angiotensin-converting enzyme) consists of two homologous, N and C domains, whereas the testis isoenzyme [tACE (testis ACE)] consists of a single C domain. Both isoenzymes are shed from the cell surface by a sheddase activity, although sACE is shed much less efficiently than tACE. We hypothesize that the N domain of sACE plays a regulatory role, by occluding a recognition motif on the C domain required for ectodomain shedding and by influencing the catalytic efficiency. To test this, we constructed two mutants: CNdom-ACE and CCdom-ACE. CNdom-ACE was shed less efficiently than sACE, whereas CCdom-ACE was shed as efficiently as tACE. Notably, cleavage occurred both within the stalk and the interdomain bridge in both mutants, suggesting that a sheddase recognition motif resides within the C domain and is capable of directly cleaving at both positions. Analysis of the catalytic properties of the mutants and comparison with sACE and tACE revealed that the kcat for sACE and CNdom-ACE was less than or equal to the sum of the kcat values for tACE and the N-domain, suggesting negative co-operativity, whereas the kcat value for the CCdom-ACE suggested positive co-operativity between the two domains. Taken together, the results provide support for (i) the existence of a sheddase recognition motif in the C domain and (ii) molecular flexibility of the N and C domains in sACE, resulting in occlusion of the C-domain recognition motif by the N domain as well as close contact of the two domains during hydrolysis of peptide substrates. PMID:15813703

Bar Code Labels

NASA Technical Reports Server (NTRS)

1988-01-01

American Bar Codes, Inc. developed special bar code labels for inventory control of space shuttle parts and other space system components. ABC labels are made in a company-developed anodizing aluminum process and consecutively marketed with bar code symbology and human readable numbers. They offer extreme abrasion resistance and indefinite resistance to ultraviolet radiation, capable of withstanding 700 degree temperatures without deterioration and up to 1400 degrees with special designs. They offer high resistance to salt spray, cleaning fluids and mild acids. ABC is now producing these bar code labels commercially or industrial customers who also need labels to resist harsh environments.

Identification of the WW domain-interaction sites in the unstructured N-terminal domain of EBV LMP 2A.

PubMed

Seo, Min-Duk; Park, Sung Jean; Kim, Hyun-Jung; Lee, Bong Jin

2007-01-09

Epstein-Barr virus latency is maintained by the latent membrane protein (LMP) 2A, which mimics the B-cell receptor (BCR) and perturbs BCR signaling. The cytoplasmic N-terminal domain of LMP2A is composed of 119 amino acids. The N-terminal domain of LMP2A (LMP2A NTD) contains two PY motifs (PPPPY) that interact with the WW domains of Nedd4 family ubiquitin-protein ligases. Based on our analysis of NMR data, we found that the LMP2A NTD adopts an overall random-coil structure in its native state. However, the region between residues 60 and 90 was relatively ordered, and seemed to form the hydrophobic core of the LMP2A NTD. This region resides between two PY motifs and is important for WW domain binding. Mapping of the residues involved in the interaction between the LMP2A NTD and WW domains was achieved by chemical shift perturbation, by the addition of WW2 and WW3 peptides. Interestingly, the binding of the WW domains mainly occurred in the hydrophobic core of the LMP2A NTD. In addition, we detected a difference in the binding modes of the two PY motifs against the two WW peptides. The binding of the WW3 peptide caused the resonances of five residues (Tyr(60), Glu(61), Asp(62), Trp(65), and Gly(66)) just behind the N-terminal PY motif of the LMP2A NTD to disappear. A similar result was obtained with WW2 binding. However, near the C-terminal PY motif, the chemical shift perturbation caused by WW2 binding was different from that due to WW3 binding, indicating that the residues near the PY motifs are involved in selective binding of WW domains. The present work represents the first structural study of the LMP2A NTD and provides fundamental structural information about its interaction with ubiquitin-protein ligase.

The New BaBar Data Reconstruction Control System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ceseracciu, Antonio

2003-06-02

The BaBar experiment is characterized by extremely high luminosity, a complex detector, and a huge data volume, with increasing requirements each year. To fulfill these requirements a new control system has been designed and developed for the offline data reconstruction system. The new control system described in this paper provides the performance and flexibility needed to manage a large number of small computing farms, and takes full benefit of OO design. The infrastructure is well isolated from the processing layer, it is generic and flexible, based on a light framework providing message passing and cooperative multitasking. The system is activelymore » distributed, enforces the separation between different processing tiers by using different naming domains, and glues them together by dedicated brokers. It provides a powerful Finite State Machine framework to describe custom processing models in a simple regular language. This paper describes this new control system, currently in use at SLAC and Padova on {approx}450 CPUs organized in 12 farms.« less

The bridge technique for pectus bar fixation: a method to make the bar un-rotatable.

PubMed

Park, Hyung Joo; Kim, Kyung Soo; Moon, Young Kyu; Lee, Sungsoo

2015-08-01

Pectus bar rotation is a major challenge in pectus repair. However, to date, no satisfactory technique to completely eliminate bar displacement has been introduced. Here, we propose a bar fixation technique using a bridge that makes the bar unmovable. The purpose of this study was to determine the efficacy of this bridge technique. A total of 80 patients underwent pectus bar repair of pectus excavatum with the bridge technique from July 2013 to July 2014. The technique involved connecting 2 parallel bars using plate-screws at the ends of the bars. To determine bar position change, the angles between the sternum and pectus bars were measured on postoperative day 5 (POD5) and 4 months (POM4) and compared. The mean patient age was 17.5 years (range, 6-38 years). The mean difference between POD5 and POM4 were 0.23° (P=.602) and 0.35° (P=.338) for the upper and lower bars, respectively. Bar position was virtually unchanged during the follow-up, and there was no bar dislocation or reoperation. A "bridge technique" designed to connect 2 parallel bars using plates and screws was demonstrated as a method to avoid pectus bar displacement. This approach was easy to implement without using sutures or invasive devices. Copyright © 2015 Elsevier Inc. All rights reserved.

Effect of sodium chloride on the structure and stability of spider silk’s N-terminal protein domain

PubMed Central

Gronau, Greta; Qin, Zhao; Buehler, Markus J.

2013-01-01

A spider’s ability to store silk protein solutions at high concentration is believed to be related to the protein’s terminal domains. It has been suggested that a shift in salt concentration and pH can have a significant influence on the assembly process. Based on experimental data, a model has been proposed in which the N-terminal domain exists as a monomer during storage and assembles into a homodimer upon spinning. Here we perform a systematic computational study using atomistic, coarse-grained and well-tempered metadynamics simulation to understand how the NaCl concentration in the solution affects the N-terminal domain of the silk protein. Our results show that a high salt concentration, as found during storage, weakens key salt bridges between the monomers, inducing a loss in bond energy by 28.6% in a single salt bridge. As a result dimer formation is less likely as 35.5% less energy is required to unfold the dimer by mechanical force. Conversely, homodimer formation appears to be more likely at low salt concentrations as the salt bridge stays at the lower energy state. The link between salt concentration, structure and stability of the N-terminal domain provides a possible mechanism that prevents premature fiber formation during storage. PMID:23833703

Automated multisyringe stir bar sorptive extraction using robust montmorillonite/epoxy-coated stir bars.

PubMed

Ghani, Milad; Saraji, Mohammad; Maya, Fernando; Cerdà, Víctor

2016-05-06

Herein we present a simple, rapid and low cost strategy for the preparation of robust stir bar coatings based on the combination of montmorillonite with epoxy resin. The composite stir bar was implemented in a novel automated multisyringe stir bar sorptive extraction system (MS-SBSE), and applied to the extraction of four chlorophenols (4-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol and pentachlorophenol) as model compounds, followed by high performance liquid chromatography-diode array detection. The different experimental parameters of the MS-SBSE, such as sample volume, selection of the desorption solvent, desorption volume, desorption time, sample solution pH, salt effect and extraction time were studied. Under the optimum conditions, the detection limits were between 0.02 and 0.34μgL(-1). Relative standard deviations (RSD) of the method for the analytes at 10μgL(-1) concentration level ranged from 3.5% to 4.1% (as intra-day RSD) and from 3.9% to 4.3% (as inter-day RSD at 50μgL(-1) concentration level). Batch-to-batch reproducibility for three different stir bars was 4.6-5.1%. The enrichment factors were between 30 and 49. In order to investigate the capability of the developed technique for real sample analysis, well water, wastewater and leachates from a solid waste treatment plant were satisfactorily analyzed. Copyright © 2016 Elsevier B.V. All rights reserved.

Testing of an actively damped boring bar featuring structurally integrated PZT stack actuators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Redmond, J.; Barney, P.

This paper summarizes the results of cutting tests performed using an actively damped boring bar to minimize chatter in metal cutting. A commercially available 2 inch diameter boring bar was modified to incorporate PZT stack actuators for controlling tool bending vibrations encountered during metal removal. The extensional motion of the actuators induce bending moments in the host structure through a two-point preloaded mounting scheme. Cutting tests performed at various speeds and depths of cuts on a hardened steel workpiece illustrate the bar`s effectiveness toward eliminating chatter vibrations and improving workpiece surface finish.

Performance in hippocampus- and PFC-dependent cognitive domains are not concomitantly impaired in rats exposed to 20cGy of 1GeV/n (56)Fe particles.

PubMed

Britten, Richard A; Miller, Vania D; Hadley, Melissa M; Jewell, Jessica S; Macadat, Evangeline

2016-08-01

NASA is currently conducting ground based experiments to determine whether the radiation environment that astronauts will encounter on deep space missions will have an impact on their long-term health and their ability to complete the various tasks during the mission. Emerging data suggest that exposure of rodents to mission-relevant HZE radiation doses does result in the impairment of various neurocognitive processes. An essential part of mission planning is a probabilistic risk assessment process that takes into account the likely incidence and severity of a problem. To date few studies have reported the impact of space radiation in a format that is amenable to PRA, and those that have only reported data for a single cognitive process. This study has established the ability of individual male Wistar rats to conduct a hippocampus-dependent (spatial memory) task and a cortex-dependent (attentional set shifting task) 90 days after exposure to 20cGy 1GeV/n (56)Fe particles. Radiation-induced impairment of performance in one cognitive domain was not consistently associated with impaired performance in the other domain. Thus sole reliance upon a single measure of cognitive performance may substantially under-estimate the risk of cognitive impairment, and ultimately it may be necessary to establish the likelihood that mission-relevant HZE doses will impair performance in the three or four cognitive domains that NASA considers to be most critical for mission success, and build a PRA using the composite data from such studies. Copyright © 2016 The Committee on Space Research (COSPAR). Published by Elsevier Ltd. All rights reserved.

Uncertainties in the deprojection of the observed bar properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zou, Yanfei; Shen, Juntai; Li, Zhao-Yu, E-mail: jshen@shao.ac.cn

2014-08-10

In observations, it is important to deproject the two fundamental quantities characterizing a bar, i.e., its length (a) and ellipticity (e), to face-on values before any careful analyses. However, systematic estimation on the uncertainties of the commonly used deprojection methods is still lacking. Simulated galaxies are well suited in this study. We project two simulated barred galaxies onto a two-dimensional (2D) plane with different bar orientations and disk inclination angles (i). Bar properties are measured and deprojected with the popular deprojection methods in the literature. Generally speaking, deprojection uncertainties increase with increasing i. All of the deprojection methods behave badlymore » when i is larger than 60°, due to the vertical thickness of the bar. Thus, future statistical studies of barred galaxies should exclude galaxies more inclined than 60°. At moderate inclination angles (i ≤ 60°), 2D deprojection methods (analytical and image stretching), and Fourier-based methods (Fourier decomposition and bar-interbar contrast) perform reasonably well with uncertainties ∼10% in both the bar length and ellipticity, whereas the uncertainties of the one-dimensional (1D) analytical deprojection can be as high as 100% in certain extreme cases. We find that different bar measurement methods show systematic differences in the deprojection uncertainties. We further discuss the deprojection uncertainty factors with the emphasis on the most important one, i.e., the three-dimensional structure of the bar itself. We construct two triaxial toy bar models that can qualitatively reproduce the results of the 1D and 2D analytical deprojections; they confirm that the vertical thickness of the bar is the main source of uncertainties.« less

The company they keep: drinking group attitudes and male bar aggression.

PubMed

Dumas, Tara M; Graham, Kathryn; Wells, Samantha

2015-05-01

The purpose of this study was to assess (a) similarities in self-reported bar-aggression-related attitudes and behaviors among members of young male groups recruited on their way to bars and (b) group-level variables associated with individual members' self-reported likelihood of perpetrating physical bar aggression in the past year, controlling for individual attitudes. Young, male, natural drinking groups recruited on their way to a bar district Thursday, Friday, and Saturday nights (n = 167, 53 groups) completed an online survey that measured whether they had perpetrated physical aggression at a bar in the past year and constructs associated with bar aggression, including attitudes toward male bar aggression and frequency of heavy episodic drinking in the past year. Intraclass correlations and chi-square tests demonstrated significant within-group similarity on bar-aggression-related attitudes and behaviors (ps < .01). Hierarchical linear modeling revealed that group attitudes toward bar aggression were significantly associated with individuals' likelihood of perpetrating physical bar aggression, controlling for individual attitudes (p < .01); however, the link between group heavy episodic drinking and self-reported bar aggression was nonsignificant in the full model. This study suggests that the most important group influence on young men's bar aggression is the attitudes of other group members. These attitudes were associated with group members' likelihood of engaging in bar aggression over and above individuals' own attitudes. A better understanding of how group attitudes and behavior affect the behavior of individual group members is needed to inform aggression-prevention programming.

Word Memory Test Performance Across Cognitive Domains, Psychiatric Presentations, and Mild Traumatic Brain Injury.

PubMed

Rowland, Jared A; Miskey, Holly M; Brearly, Timothy W; Martindale, Sarah L; Shura, Robert D

2017-05-01

The current study addressed two aims: (i) determine how Word Memory Test (WMT) performance relates to test performance across numerous cognitive domains and (ii) evaluate how current psychiatric disorders or mild traumatic brain injury (mTBI) history affects performance on the WMT after excluding participants with poor symptom validity. Participants were 235 Iraq and Afghanistan-era veterans (Mage = 35.5) who completed a comprehensive neuropsychological battery. Participants were divided into two groups based on WMT performance (Pass = 193, Fail = 42). Tests were grouped into cognitive domains and an average z-score was calculated for each domain. Significant differences were found between those who passed and those who failed the WMT on the memory, attention, executive function, and motor output domain z-scores. WMT failure was associated with a larger performance decrement in the memory domain than the sensation or visuospatial-construction domains. Participants with a current psychiatric diagnosis or mTBI history were significantly more likely to fail the WMT, even after removing participants with poor symptom validity. Results suggest that the WMT is most appropriate for assessing validity in the domains of attention, executive function, motor output and memory, with little relationship to performance in domains of sensation or visuospatial-construction. Comprehensive cognitive batteries would benefit from inclusion of additional performance validity tests in these domains. Additionally, symptom validity did not explain higher rates of WMT failure in individuals with a current psychiatric diagnosis or mTBI history. Further research is needed to better understand how these conditions may affect WMT performance. Published by Oxford University Press 2016. This work is written by (a) US Government employee(s) and is in the public domain in the US.

School-Level Practices and Perceptions Associated with Salad Bars in Schools

ERIC Educational Resources Information Center

Bruening, Meg; Adams, Marc A.; Ohri-Vachaspati, Punam; Hurley, Jane

2018-01-01

Background: Salad bars are placed in schools to promote fruit and vegetable consumption among students. This study assessed differences in school nutrition practices and perceptions in schools with and without salad bars. Methods: Cross-sectional surveys were completed by school nutrition managers (N = 648) in Arizona schools participating in the…

Measurement of |V{sub cb}| using {bar B}{sup 0} {yields} D*{sup +}{ell}{sup -}{bar {nu}}{sub {ell}} Decays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Della Ricca, Giuseppe

A preliminary measurement of |V{sub cb}| and the branching fraction {Beta}({bar B}{sup 0} {yields} D*{sup +}{ell}{sup -}{bar {nu}}{sub {ell}}) has been performed based on a sample of about 55,700 {bar B}{sup 0} {yields} D*{sup +}{ell}{sup -}{bar {nu}}{sub {ell}} decays recorded with the BABAR detector. The decays are identified in the D*{sup +} {yields} D{sup 0}{pi}{sup +} final state, with the D{sup 0} reconstructed in three different decay modes. The differential decay rate is measured as a function of the relativistic boost of the D*{sup +} in the {bar B}{sup 0} rest frame. The value of the differential decay rate atmore » ''zero recoil'', namely the point at which the D*{sup +} is at rest in the {bar B}{sup 0} frame, is predicted in Heavy Quark Effective Theory as a kinematic factor times F(1)|V{sub cb}|, where F is the unique form factor governing the decay. We extrapolate the measured differential decay rate to the zero recoil point and obtain F(1)|V{sub cb}| = (34.03 {+-} 0.24 {+-} 1.31) x 10{sup -3}. Using a theoretical calculation for F(1) we extract |V{sub cb}| = (37.27 {+-} 0.26(stat.) {+-} 1.43(syst.){sub -1.2}{sup +1.5}(theo.)) x 10{sup -3}. From the integrated decay rate we obtain {Beta}({bar B}{sup 0} {yields} D*{sup +}{ell}{sup -}{bar {nu}}{sub {ell}}) = (4.68 {+-} 0.03 {+-} 0.29)%.« less

Overdentures in the edentulous mandible supported by implants and retained by a Dolder bar: a 5-year prospective study.

PubMed

Heschl, Alexander; Payer, Michael; Clar, Volker; Stopper, Marlene; Wegscheider, Walther; Lorenzoni, Martin

2013-08-01

This prospective study was performed to evaluate the outcomes of XiVE® S plus implants (Dentsply Friadent, Mannheim, Germany) following conventional restoration with bar structures and overdentures in the edentulous mandible. A total of 39 patients were treated with four interforaminal implants (n = 156) splinted by a Dolder bar. Overdentures were attached to the bars after 3 months of healing. As primary outcome measures, clinical and radiological parameters were evaluated at the time of implant placement (baseline) and once a year (1, 2, 3, 4, 5 years) after functional loading. Secondary outcome measures included (i) primary stability and surgical complications, as well as (ii) Periotest® (Medizintechnik Gulden, Modautal, Germany) values, implant survival, and prosthetic complications at baseline and follow-up. A total of 156 implants were placed. The vast majority (n = 149) were tightened to >30 Ncm, while torques in the range of 20-30 Ncm were obtained in the remaining cases (n = 7). Mean crestal bone levels around the implants were 0.41 mm at baseline and 1.04/1.20/1.34/1.45/1.44 mm after 1/2/3/4/5 years respectively. The mean values of the plaque, calculus, bleeding, and mucosal indices remained low throughout this period. The reported follow-up periods involved one implant loss after 3 months (survival rate: 99.4%) and one implant failure after 4 years (success rate: 98.4%). Prosthetic complications included factures of bars (n = 3) and denture teeth (n = 7). Prosthetic survival was 100%. Dolder bars to restore oral implants in the edentulous mandible appear to offer a high rate of implant survival, good stability of the peri-implant tissue, and a low rate of prosthetic complications. © 2011 Wiley Periodicals, Inc.

Chemical enrichment in isolated barred spiral galaxies.

NASA Astrophysics Data System (ADS)

Martel, Hugo; Carles, Christian; Robichaud, Fidéle; Ellison, Sara L.; Williamson, David J.

2018-04-01

To investigate the role of bars in the chemical evolution of isolated disc galaxies, we performed a series of 39 gas dynamical simulations of isolated barred and unbarred galaxies with various masses, initial gas fractions, and AGN feedback models. The presence of a bar drives a substantial amount of gas toward the central region of the galaxy. In the most massive galaxies, this results in a violent starburst, followed by a drop in star formation resulting from gas exhaustion. The time delay between Type Ia and Type II supernovae explosions means that barred galaxies experience a rapid increase in [O/H] in the central region, and a much more gradual increase in [Fe/H]. In unbarred galaxies, star formation proceeds at a slow and steady rate, and oxygen and iron are produced at steady rates which are similar except for a time offset. Comparing the abundance ratios in barred and unbarred galaxies with the same central stellar mass M*, we find in barred galaxies an enhancement of 0.07 dex in [O/H], 0.05 dex in [Fe/H], and 0.05 dex in [O/Fe]. The [O/H] enhancement is in excellent agreement with observations from the SDSS. The initial gas fraction has very little effect on the abundance ratios in barred and unbarred galaxies, unless the galaxies experience a starburst. We considered AGN-host galaxies located near the bottom of the AGN regime, M* ≳ 3 × 1010M⊙, where AGN feedback dominates over supernovae feedback. We found that the impact of AGN feedback on the central abundances is marginal.

Prevalence of smoking among bar workers prior to the Republic of Ireland smokefree workplace legislation.

PubMed

Mullally, B J; Greiner, B A; Allwright, S; Paul, G; Perry, I J

2008-12-01

This study establishes baseline prevalence of smoking and cigarette consumption among Cork bar workers prior to the Republic of Ireland's (ROI) smokefree workplace legislation and compares gender- and age-specific smoking rates and estimates the adjusted odds of being a smoker for Cork bar workers relative to the general population. Cross-sectional random sample of bar workers in Cork city and cross-sectional random telephone survey of the general population were conducted prior to the smokefree legislation. Self reported smoking prevalence among Cork bar workers (n = 129) was 54% (58% using cotinine-validated measures), with particularly high rates in women (70%) and 18-28 years old (72%). Within the ROI (n = 1,240) sub-sample rates were substantially lower at 28%. Bar workers were twice as likely to be smokers as the general population sub-sample (OR = 2.15). Cork bar workers constitute an occupational group with an extremely high smoking prevalence.

Unique bar-like sulfur-doped C3N4/TiO2 nanocomposite: Excellent visible light driven photocatalytic activity and mechanism study

NASA Astrophysics Data System (ADS)

Zhao, Yu; Xu, Shiping; Sun, Xiang; Xu, Xing; Gao, Baoyu

2018-04-01

In this work, a nanocomposite of TiO2 nanoparticles coupled with sulfur-doped C3N4 (S-C3N4) laminated layer was successfully fabricated using a facile impregnation method and the nanocomposite exhibited superior photocatalytic activity in pollutant removal under visible light irradiation, compared to bare TiO2, g-C3N4 and binary C3N4-TiO2 nanocomposite. The enhanced photocatalytic activity was benefited from the efficient migration and transformation of electron-hole (e--h+) pairs, improved visible light absorption capability, and relatively large specific surface area induce by sulfur doping. Interestingly, the introduction of sulfur changes regulated the morphology of g-C3N4 leading to the formation of ultrathin g-C3N4 layer nanosheet assemblies and unique bar-like g-C3N4/TiO2 nanocomposite, which is beneficial for the outstanding performance of the product. In addition, trapping experiment was carried out to identify the main active species in the photocatalytic reaction over the S-C3N4/TiO2 photocatalyst, and functional mechanism of the composite was proposed. This work may provide new ideas for the fabrication and utilization of highly efficient photocatalyst with excellent visible light response in environmental purification applications.

Development of self-sensing BFRP bars with distributed optic fiber sensors

NASA Astrophysics Data System (ADS)

Tang, Yongsheng; Wu, Zhishen; Yang, Caiqian; Shen, Sheng; Wu, Gang; Hong, Wan

2009-03-01

In this paper, a new type of self-sensing basalt fiber reinforced polymer (BFRP) bars is developed with using the Brillouin scattering-based distributed optic fiber sensing technique. During the fabrication, optic fiber without buffer and sheath as a core is firstly reinforced through braiding around mechanically dry continuous basalt fiber sheath in order to survive the pulling-shoving process of manufacturing the BFRP bars. The optic fiber with dry basalt fiber sheath as a core embedded further in the BFRP bars will be impregnated well with epoxy resin during the pulling-shoving process. The bond between the optic fiber and the basalt fiber sheath as well as between the basalt fiber sheath and the FRP bar can be controlled and ensured. Therefore, the measuring error due to the slippage between the optic fiber core and the coating can be improved. Moreover, epoxy resin of the segments, where the connection of optic fibers will be performed, is uncured by isolating heat from these parts of the bar during the manufacture. Consequently, the optic fiber in these segments of the bar can be easily taken out, and the connection between optic fibers can be smoothly carried out. Finally, a series of experiments are performed to study the sensing and mechanical properties of the propose BFRP bars. The experimental results show that the self-sensing BFRP bar is characterized by not only excellent accuracy, repeatability and linearity for strain measuring but also good mechanical property.

An Evaluation of the Performance Diagnostic Checklist-Human Services (PDC-HS) Across Domains.

PubMed

Wilder, David A; Lipschultz, Joshua; Gehrman, Chana

2018-06-01

The Performance Diagnostic Checklist-Human Services (PDC-HS) is an informant-based tool designed to assess the environmental variables that contribute to poor employee performance in human service settings. Although the PDC-HS has been shown to effectively identify variables contributing to problematic performance, interventions based on only two of the four PDC-HS domains have been evaluated to date. In addition, the extent to which PDC-HS-indicated interventions are more effective than nonindicated interventions for two domains remains unclear. In the current study, we administered the PDC-HS to supervisors to assess the variables contributing to infrequent teaching of verbal operants and use of a timer by therapists at a center-based autism treatment program. Each of the four PDC-HS domains was identified as contributing to poor performance for at least one therapist. We then evaluated PDC-HS-indicated interventions for each domain. In addition, to assess the predictive validity of the tool, we evaluated various nonindicated interventions prior to implementing a PDC-HS-indicated intervention for two of the four domains. Results suggest that the PDC-HS-indicated interventions were effective across all four domains and were more effective than the nonindicated interventions for the two domains for which they were evaluated. Results are discussed in terms of the utility of the PDC-HS to identify appropriate interventions to manage therapist performance in human service settings.

Selecting and Effectively Using Sports Drinks, Carbohydrate Gels and Energy Bars

MedlinePlus

... and Effectively Using Sports Drinks, Carbohydrate Gels and Energy Bars Depending upon the length of your workout ... can hinder performance. Sports drinks, carbohydrate gels and energy bars can help restore your body’s fluids and ...

The study of two barred galaxies with curious kinematical features

NASA Astrophysics Data System (ADS)

Saburova, A. S.; Katkov, I. Y.; Khoperskov, S. A.; Zasov, A. V.; Uklein, R. I.

2017-09-01

We performed long-slit spectral observations of two SB-type galaxies: NGC 5347 and UGC 1344. They were previously suspected as the galaxies with unusually low mass-to-light ratios (on the ground of mass estimates from the H I linewidths), which are in conflict with their observed colours. The observations were conducted at the Russian 6-m telescope. The aim of this study was to clarify the kinematics and structure, as well as the properties of stellar populations of the galaxies. The results of observations disproved the peculiarly low mass-to-light ratios of both galaxies. The most probable reasons of underestimation of their masses are discussed. We tried to reproduce the main observed features of kinematical profiles of the galaxies in the N-body simulations of barred galaxies. We found that both galaxies possess central components of different structures. Indeed, the age and velocity dispersion of stellar population in NGC 5347 are low in its innermost part in comparison to that of the bulge or a bar, which agrees with the presence of nuclear kinematically decoupled disc. It probably was formed due to the bar that supplied the inner region with gas. The kinematical profiles of the second galaxy UGC 1344 give evidence in favour of the central peanut-shaped bulge. In spite of the different luminosities of the two galaxies, they possess nearly equal (close to solar) central stellar abundance and the flattening of the stellar metallicity gradient in the bar regions. However, in the less luminous NGC 5347, the mean stellar age is younger than that in UGC 1344.

Triple bar, high efficiency mechanical sealer

DOEpatents

Pak, Donald J.; Hawkins, Samantha A.; Young, John E.

2013-03-19

A clamp with a bottom clamp bar that has a planar upper surface is provided. The clamp may also include a top clamp bar connected to the bottom clamp bar, and a pressure distribution bar between the top clamp bar and the bottom clamp bar. The pressure distribution bar may have a planar lower surface in facing relation to the upper surface of the bottom clamp bar. An object is capable of being disposed in a clamping region between the upper surface and the lower surface. The width of the planar lower surface may be less than the width of the upper surface within the clamping region. Also, the pressure distribution bar may be capable of being urged away from the top clamp bar and towards the bottom clamp bar.

Application of smart BFRP bars with distributed fiber optic sensors into concrete structures

NASA Astrophysics Data System (ADS)

Tang, Yongsheng; Wu, Zhishen; Yang, Caiqian; Wu, Gang; Zhao, Lihua; Song, Shiwei

2010-04-01

In this paper, the self-sensing and mechanical properties of concrete structures strengthened with a novel type of smart basalt fiber reinforced polymer (BFRP) bars were experimentally studied, wherein the sensing element is Brillouin scattering-based distributed optical fiber sensing technique. First, one of the smart bars was applied to strengthen a 2m concrete beam under a 4-points static loading manner in the laboratory. During the experiment, the bar can measure the inner strain changes and monitor the randomly distributed cracks well. With the distributed strain information along the bar, the distributed deformation of the beam can be calculated, and the structural health can be monitored and evaluated as well. Then, two smart bars with a length of about 70m were embedded into a concrete airfield pavement reinforced by long BFRP bars. In the field test, all the optical fiber sensors in the smart bars survived the whole concrete casting process and worked well. From the measured data, the concrete cracks along the pavement length can be easily monitored. The experimental results also confirmed that the bars can strengthen the structures especially after the yielding of steel bars. All the results confirm that this new type of smart BFRP bars show not only good sensing performance but also mechanical performance in the concrete structures.

Automatic detection of service initiation signals used in bars

PubMed Central

Loth, Sebastian; Huth, Kerstin; De Ruiter, Jan P.

2013-01-01

Recognizing the intention of others is important in all social interactions, especially in the service domain. Enabling a bartending robot to serve customers is particularly challenging as the system has to recognize the social signals produced by customers and respond appropriately. Detecting whether a customer would like to order is essential for the service encounter to succeed. This detection is particularly challenging in a noisy environment with multiple customers. Thus, a bartending robot has to be able to distinguish between customers intending to order, chatting with friends or just passing by. In order to study which signals customers use to initiate a service interaction in a bar, we recorded real-life customer-staff interactions in several German bars. These recordings were used to generate initial hypotheses about the signals customers produce when bidding for the attention of bar staff. Two experiments using snapshots and short video sequences then tested the validity of these hypothesized candidate signals. The results revealed that bar staff responded to a set of two non-verbal signals: first, customers position themselves directly at the bar counter and, secondly, they look at a member of staff. Both signals were necessary and, when occurring together, sufficient. The participants also showed a strong agreement about when these cues occurred in the videos. Finally, a signal detection analysis revealed that ignoring a potential order is deemed worse than erroneously inviting customers to order. We conclude that (a) these two easily recognizable actions are sufficient for recognizing the intention of customers to initiate a service interaction, but other actions such as gestures and speech were not necessary, and (b) the use of reaction time experiments using natural materials is feasible and provides ecologically valid results. PMID:24009594

Conformation changes, N-terminal involvement and cGMP signal relay in phosphodiesterase-5 GAF domain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, H.; Robinson, H.; Ke, H.

2010-12-03

The activity of phosphodiesterase-5 (PDE5) is specific for cGMP and is regulated by cGMP binding to GAF-A in its regulatory domain. To better understand the regulatory mechanism, x-ray crystallographic and biochemical studies were performed on constructs of human PDE5A1 containing the N-terminal phosphorylation segment, GAF-A, and GAF-B. Superposition of this unliganded GAF-A with the previously reported NMR structure of cGMP-bound PDE5 revealed dramatic conformational differences and suggested that helix H4 and strand B3 probably serve as two lids to gate the cGMP-binding pocket in GAF-A. The structure also identified an interfacial region among GAF-A, GAF-B, and the N-terminal loop, whichmore » may serve as a relay of the cGMP signal from GAF-A to GAF-B. N-terminal loop 98-147 was physically associated with GAF-B domains of the dimer. Biochemical analyses showed an inhibitory effect of this loop on cGMP binding and its involvement in the cGMP-induced conformation changes.« less

Barring intervention? Lesbian and gay bars as an underutilized venue for tobacco interventions.

PubMed

Leibel, Katherine; Lee, Joseph G L; Goldstein, Adam O; Ranney, Leah M

2011-07-01

Lesbian, gay, bisexual, and transgender (LGBT) communities are at high risk for tobacco use. While LGBT communities have historically considered bars to be safe places to socialize and congregate, these spaces are often tobacco-friendly environments and may have potential as sites for much needed intervention. Only a few public health interventions have attempted to work through bars and clubs to decrease tobacco use in the LGBT populations. Evidence from HIV prevention suggests some potential interventions in bars, and the tobacco industry has worked extensively (and successfully) to utilize bars in marketing efforts. Lesbian and gay bars are underutilized in tobacco control, suggesting missed avenues for chronic disease prevention programs. Researchers and communities should continue to recognize the importance of clean indoor air laws covering bars and develop additional strategies for reaching LGBT populations with disparities.

Etched poly(ether ether ketone) jacket stir bar with detachable dumbbell-shaped structure for stir bar sorptive extraction.

PubMed

Zhou, Wei; Wang, Chenlu; Wang, Xuemei; Chen, Zilin

2018-06-08

Development of stir bar sorptive extraction (SBSE) device with high stability and extraction efficiency is critical and challenging by date. In this work, etched poly(ether ether ketone) (PEEK) tube with high mechanical strength and large specific surface area was used as jacket for SBSE device. By etching with concentrated sulfuric acid, the smooth outer surface of PEEK become porous with plenty of micro holes, which was beneficial for coating of sorbents and significantly improved the extraction performance. After functionalized by bio-polydopamine method, strong hydrophobic p-naphtholbenzein molecular was immobilized onto the chemical resistant PEEK surface (PNB@E-PEEK) as stationary phase. We also firstly developed a simple detachable dumbbell-shaped structure for improving the workability of PEEK jacket stir bar. The dumbbell-shaped construction can eliminate the friction between stir bar and container, and the design of detachable structure make elution can be accomplished easier with small amount of organic solvent. It was interesting that the developed detachable dumbbell-shaped PNB@E-PEEK stir bar showed exceptional stability and extraction efficiency for SBSE enrichment of multiple analytes including several Sudan dyes, triazines, polycyclic aromatic hydrocarbons (PAHs), alkaloids and flavonoid. By coupling with high performance liquid chromatography-ultraviolet detection (HPLC-UV), PNB@E-PEEK stir bar based SBSE-HPLC-UV method was applied for the analysis of common Sudan dye pollutants. The method showed low limits of detection (0.02-0.03 ng/mL), good linearity (R 2  ≥ 0.9979) and good reproducibility (relative standard deviation ≤ 7.96%). It has been successfully applied to determine three dye pollutants in tap and lake water. Copyright © 2018 Elsevier B.V. All rights reserved.

Chemical enrichment in isolated barred spiral galaxies

NASA Astrophysics Data System (ADS)

Martel, Hugo; Carles, Christian; Robichaud, Fidèle; Ellison, Sara L.; Williamson, David J.

2018-07-01

To investigate the role of bars in the chemical evolution of isolated disc galaxies, we performed a series of 39 gas dynamical simulations of isolated barred and unbarred galaxies with various masses, initial gas fractions, and active galactic nucleus (AGN) feedback models. The presence of a bar drives a substantial amount of gas towards the central region of the galaxy. In the most massive galaxies, this results in a violent starburst, followed by a drop in star formation resulting from gas exhaustion. The time delay between Type Ia and Type II supernovae explosions means that barred galaxies experience a rapid increase in [O/H] in the central region, and a much more gradual increase in [Fe/H]. In unbarred galaxies, star formation proceeds at a slow and steady rate, and oxygen and iron are produced at steady rates which are similar except for a time offset. Comparing the abundance ratios in barred and unbarred galaxies with the same central stellar mass M*, we find in barred galaxies an enhancement of 0.07 dex in [O/H], 0.05 dex in [Fe/H], and 0.05 dex in [O/Fe]. The [O/H] enhancement is in excellent agreement with observations from the SDSS. The initial gas fraction has very little effect on the abundance ratios in barred and unbarred galaxies, unless the galaxies experience a starburst. We considered AGN-host galaxies located near the bottom of the AGN regime, M* ≳ 3 × 1010M⊙, where AGN feedback dominates over supernovae feedback. We found that the impact of AGN feedback on the central abundances is marginal.

Machine learning models for lipophilicity and their domain of applicability.

PubMed

Schroeter, Timon; Schwaighofer, Anton; Mika, Sebastian; Laak, Antonius Ter; Suelzle, Detlev; Ganzer, Ursula; Heinrich, Nikolaus; Müller, Klaus-Robert

2007-01-01

Unfavorable lipophilicity and water solubility cause many drug failures; therefore these properties have to be taken into account early on in lead discovery. Commercial tools for predicting lipophilicity usually have been trained on small and neutral molecules, and are thus often unable to accurately predict in-house data. Using a modern Bayesian machine learning algorithm--a Gaussian process model--this study constructs a log D7 model based on 14,556 drug discovery compounds of Bayer Schering Pharma. Performance is compared with support vector machines, decision trees, ridge regression, and four commercial tools. In a blind test on 7013 new measurements from the last months (including compounds from new projects) 81% were predicted correctly within 1 log unit, compared to only 44% achieved by commercial software. Additional evaluations using public data are presented. We consider error bars for each method (model based error bars, ensemble based, and distance based approaches), and investigate how well they quantify the domain of applicability of each model.

Directed evolution of the TALE N-terminal domain for recognition of all 5′ bases

PubMed Central

Lamb, Brian M.; Mercer, Andrew C.; Barbas, Carlos F.

2013-01-01

Transcription activator-like effector (TALE) proteins can be designed to bind virtually any DNA sequence. General guidelines for design of TALE DNA-binding domains suggest that the 5′-most base of the DNA sequence bound by the TALE (the N0 base) should be a thymine. We quantified the N0 requirement by analysis of the activities of TALE transcription factors (TALE-TF), TALE recombinases (TALE-R) and TALE nucleases (TALENs) with each DNA base at this position. In the absence of a 5′ T, we observed decreases in TALE activity up to >1000-fold in TALE-TF activity, up to 100-fold in TALE-R activity and up to 10-fold reduction in TALEN activity compared with target sequences containing a 5′ T. To develop TALE architectures that recognize all possible N0 bases, we used structure-guided library design coupled with TALE-R activity selections to evolve novel TALE N-terminal domains to accommodate any N0 base. A G-selective domain and broadly reactive domains were isolated and characterized. The engineered TALE domains selected in the TALE-R format demonstrated modularity and were active in TALE-TF and TALEN architectures. Evolved N-terminal domains provide effective and unconstrained TALE-based targeting of any DNA sequence as TALE binding proteins and designer enzymes. PMID:23980031

Compliance with smoke-free policies in Korean bars and restaurants: A descriptive analysis in California

PubMed Central

Irvin, Veronica L.; Hofstetter, C. Richard; Nichols, Jeanne F.; Chambers, Christina D.; Usita, Paula M.; Norman, Gregory J.; Kang, Sunny; Hovell, Melbourne F.

2015-01-01

Objective Compliance with California's smoke-free restaurant and bar policies may be more a function of social contingencies and less a function of legal contingencies. The aims of this study are: 1) to report indications of compliance with smoke-free legislation in Korean bars and restaurants in California; 2) to examine the demographic, smoking status, and acculturation factors of who smoked indoors; and 3) to report social cues in opposition to smoking among a sample of Koreans in California. Method Data were collected by telephone surveys administered by bilingual interviewers between 2007– 2009, and included California adults of Korean descent who visited a Korean bar or restaurant in a typical month (N=2,173, 55% female). Results 1% of restaurant-going participants smoked inside while 7% observed someone else smoke inside a Korean restaurant. 23% of bar-going participants smoked inside and 65% observed someone else smoke inside a Korean bar. Presence of ashtrays was related to indoor smoking in bars and restaurants. Among participants who observed smoking, a higher percentage observed someone ask a smoker to stop (17.6%) or gesture to a smoker (27.0%) inside Korean restaurants (N=169) than inside Korean bars (n=141, 17.0% observed verbal cue and 22.7% observed gesture). Participants who smoked inside were significantly younger and more acculturated than participants who did not. Less acculturated participants were significantly more to likely to be told to stop smoking. Conclusions Ten years after implementation of ordinances, smoking was common in Korean bars in California. PMID:25735336

Compliance with smoke-free policies in korean bars and restaurants in california: a descriptive analysis.

PubMed

Irvin, Veronica L; Hofstetter, C Richard; Nichols, Jeanne F; Chambers, Christina D; Usita, Paula M; Norman, Gregory J; Kang, Sunny; Hovell, Melbourne F

2015-01-01

Compliance with California's smoke-free restaurant and bar policies may be more a function of social contingencies and less a function of legal contingencies. The aims of this study were: 1) to report indications of compliance with smoke-free legislation in Korean bars and restaurants in California; 2) to examine the demographic, smoking status, and acculturation factors of who smoked indoors; and 3) to report social cues in opposition to smoking among a sample of Koreans in California. Data were collected by telephone surveys administered by bilingual interviewers between 2007-2009, and included California adults of Korean descent who visited a Korean bar or restaurant in a typical month (N=2,173, 55% female). 1% of restaurant-going participants smoked inside while 7% observed someone else smoke inside a Korean restaurant. Some 23% of bar-going participants smoked inside and 65% observed someone else smoke inside a Korean bar. Presence of ashtrays was related to indoor smoking in bars and restaurants. Among participants who observed smoking, a higher percentage observed someone ask a smoker to stop (17.6%) or gesture to a smoker (27.0%) inside Korean restaurants (N=169) than inside Korean bars (n=141, 17.0% observed verbal cue and 22.7% observed gesture). Participants who smoked inside were significantly younger and more acculturated than participants who did not. Less acculturated participants were significantly more to likely to be told to stop smoking. Ten years after implementation of ordinances, smoking appears to be common in Korean bars in California.

DAMPING OF THE MILKY WAY BAR BY MANIFOLD-DRIVEN SPIRALS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Łokas, Ewa L.

2016-10-10

We describe a new phenomenon of “bar damping” that may have played an important role in shaping the Milky Way bar and bulge as well as its spiral structure. We use a collisionless N -body simulation of a Milky Way–like galaxy initially composed of a dark matter halo and an exponential disk with a Toomre parameter slightly above unity. In this configuration, dominated by the disk in the center, a bar forms relatively quickly, after 1 Gyr of evolution. This is immediately followed by the formation of two manifold-driven spiral arms and the outflow of stars that modifies the potentialmore » in the vicinity of the bar, apparently shifting the position of the L {sub 1}/ L {sub 2} Lagrange points. This modification leads to the shortening of the bar and the creation of a next generation of manifold-driven spiral arms at a smaller radius. The process repeats itself a few times over the next 0.5 Gyr resulting in further substantial weakening and shortening of the bar. The time when the damping comes to an end coincides with the first buckling episode in the bar that rebuilds the orbital structure so that no more new spiral arms are formed. The morphology of the bar and the spiral structure at this time show remarkable similarity to the present properties of the Milky Way. Later on, the bar starts to grow rather steadily again, weakened only by subsequent buckling episodes occurring at more distant parts of the disk.« less

Interference of Nonstandard Interactions with Standard Model in {B^0} \\to {π ^0}\\bar vv, B_c^ - \\to {D^ - }\\bar vv and \\bar B_s^0 \\to {K^0}\\bar vv Decays

NASA Astrophysics Data System (ADS)

Mahmood, Shakeel; Tahir, Farida; Mir, Azeem

2018-05-01

We study the contributions of nonstandard neutrino interactions (NSI) to the rare decays of pseudoscalar mesons involving neutrinos in the final state {B^0} \\to {π ^0}\\bar vv, B_c^ - \\to {D^ - }\\bar vv and \\bar B_s^0 \\to {\\bar K^0}\\bar vv, It is pointed that dominant contribution comes from the interference between standard model and nonstandard interaction We predict limits on NSIs free parameter ɛ uL ττ and compare them with experimental data. We further compare our results with perturbative QCD (pQCD) and QCD results for these reactions.

Design and Evaluation of a Prosthetic Knee Joint Using the Geared Five-Bar Mechanism.

PubMed

Sun, Yuanxi; Ge, Wenjie; Zheng, Jia; Dong, Dianbiao

2015-11-01

This paper presents the mechanical design, dynamics analysis and ankle trajectory analysis of a prosthetic knee joint using the geared five-bar mechanism. Compared with traditional four-bar or six-bar mechanisms, the geared five-bar mechanism is better at performing diverse movements and is easy to control. This prosthetic knee joint with the geared five-bar mechanism is capable of fine-tuning its relative instantaneous center of rotation and ankle trajectory. The centrode of this prosthetic knee joint, which is mechanically optimized according to the centrode of human knee joint, is better in the bionic performance than that of a prosthetic knee joint using the four-bar mechanism. Additionally, the stability control of this prosthetic knee joint during the swing and stance phase is achieved by a motor. By adjusting the gear ratio of this prosthetic knee joint, the ankle trajectories of both unilateral and bilateral amputees show less deviations from expected than that of the four-bar knee joint.

Abl N-terminal Cap stabilization of SH3 domain dynamics†

PubMed Central

Chen, Shugui; Dumitrescu, Teodora Pene; Smithgall, Thomas E.; Engen, John R.

2008-01-01

Crystal structures and other biochemical data indicate that the N-terminal cap (NCap) region of the Abelson tyrosine kinase (c-Abl) is important for maintaining the downregulated conformation of the kinase domain. The exact contributions that NCap makes in stabilizing the various intramolecular interactions within c-Abl are less clear. While the NCap appears important for locking the SH3/SH2 domains to the back of the kinase domain, there may be other more subtle elements of regulation. Hydrogen exchange (HX) and mass spectrometry (MS) were used to determine if the NCap contributes to intramolecular interactions involving the Abl SH3 domain. Under physiological conditions, the Abl SH3 domain underwent partial unfolding and its unfolding half-life was slowed during binding to the SH2-kinase linker, providing a unique assay to test NCap-induced stabilization of the SH3 domain in various constructs. The results showed that NCap stabilizes the dynamics of the SH3 domain in certain constructs but does not increase the relative affinity of the SH3 domain for the native SH2-kinase linker. The stabilization effect was absent in constructs of just NCap + SH3 but was obvious when the SH2 domain and the SH2-kinase linker were present. These results suggest that interactions between NCap and the SH3 domain can contribute to c-Abl stabilization in constructs that contain at least the SH2 domain, an effect that may partially compensate for the absence of the negative regulatory C-terminal tail found in the related Src family of kinases. PMID:18452309

Coffee straw can replace Hader bar for bar retained overdentures--a clinical report.

PubMed

Guttal, S S; Shetty, U S

2012-12-01

Bar attachment system provides retention and support for the overdenture. Retention of a mandibular denture can be achieved by an implant-retained or natural tooth-retained bar and stud attachment in the anterior segment of the mandible. A simple and cost effective treatment for more complex implant overdenture is the concept of conventional tooth-retained overdentures. The authors present a clinical report of a patient treated with a mandibular tooth-borne overdenture with a bar. The bar was fabricated using a coffee straw.

Steel Bar corrosion monitoring based on encapsulated piezoelectric sensors

NASA Astrophysics Data System (ADS)

Xu, Ying; Tang, Tianyou

2018-05-01

The durability of reinforced concrete has a great impact on the structural bearing capacity, while the corrosion of steel bars is the main reason for the degradation of structural durability. In this paper, a new type of encapsulated cement based piezoelectric sensor is developed and its working performance is verified. The consistency of the finite element simulation and the experimental results shows the feasibility of monitoring the corrosion of steel bars using encapsulated piezoelectric sensors. The research results show that the corrosion conditions of the steel bars can be determined by the relative amplitude of the measured signal through the encapsulated piezoelectric sensor.

Structure of the USP15 N-terminal domains: a β-hairpin mediates close association between the DUSP and UBL domains.

PubMed

Harper, Stephen; Besong, Tabot M D; Emsley, Jonas; Scott, David J; Dreveny, Ingrid

2011-09-20

Ubiquitin specific protease 15 (USP15) functions in COP9 signalosome mediated regulation of protein degradation and cellular signaling through catalyzing the ubiquitin deconjugation reaction of a discrete number of substrates. It influences the stability of adenomatous polyposis coli, IκBα, caspase-3, and the human papillomavirus type 16 E6. USP15 forms a subfamily with USP4 and USP11 related through a shared presence of N-terminal "domain present in ubiquitin specific proteases" (DUSP) and "ubiquitin-like" (UBL) domains (DU subfamily). Here we report the 1.5 Å resolution crystal structure of the human USP15 N-terminal domains revealing a 80 Å elongated arrangement with the DU domains aligned in tandem. This architecture is generated through formation of a defined interface that is dominated by an intervening β-hairpin structure (DU finger) that engages in an intricate hydrogen-bonding network between the domains. The UBL domain is closely related to ubiquitin among β-grasp folds but is characterized by the presence of longer loop regions and different surface characteristics, indicating that this domain is unlikely to act as ubiquitin mimic. Comparison with the related murine USP4 DUSP-UBL crystal structure reveals that the main DU interdomain contacts are conserved. Analytical ultracentrifugation, small-angle X-ray scattering, and gel filtration experiments revealed that USP15 DU is monomeric in solution. Our data provide a framework to advance study of the structure and function of the DU subfamily. © 2011 American Chemical Society

Dynamic analysis of four bar planar mechanism extended to six-bar planar mechanism with variable topology

NASA Astrophysics Data System (ADS)

Belleri, Basayya K.; Kerur, Shravankumar B.

2018-04-01

A computer-oriented procedure for solving the dynamic force analysis problem for general planar mechanisms is presented. This paper provides position analysis, velocity analysis, acceleration analysis and force analysis of six bar mechanism with variable topology approach. Six bar mechanism is constructed by joining two simple four bar mechanisms. Initially the position, velocity and acceleration analysis of first four bar mechanism are determined by using the input parameters. The outputs (angular displacement, velocity and acceleration of rocker)of first four bar mechanism are used as input parameter for the second four bar mechanism and the position, velocity, acceleration and forces are analyzed. With out-put parameters of second four-bar mechanism the force analysis of first four-bar mechanism is carried out.

The Role of the N-Domain in the ATPase Activity of the Mammalian AAA ATPase p97/VCP*

PubMed Central

Niwa, Hajime; Ewens, Caroline A.; Tsang, Chun; Yeung, Heidi O.; Zhang, Xiaodong; Freemont, Paul S.

2012-01-01

p97/valosin-containing protein (VCP) is a type II ATPase associated with various cellular activities that forms a homohexamer with each protomer containing an N-terminal domain (N-domain); two ATPase domains, D1 and D2; and a disordered C-terminal region. Little is known about the role of the N-domain or the C-terminal region in the p97 ATPase cycle. In the p97-associated human disease inclusion body myopathy associated with Paget disease of bone and frontotemporal dementia, the majority of missense mutations are located at the N-domain D1 interface. Structure-based predictions suggest that such mutations affect the interaction of the N-domain with D1. Here we have tested ten major inclusion body myopathy associated with Paget disease of bone and frontotemporal dementia-linked mutants for ATPase activity and found that all have increased activity over the wild type, with one mutant, p97A232E, having three times higher activity. Further mutagenesis of p97A232E shows that the increase in ATPase activity is mediated through D2 and requires both the N-domain and a flexible ND1 linker. A disulfide mutation that locks the N-domain to D1 in a coplanar position reversibly abrogates ATPase activity. A cryo-EM reconstruction of p97A232E suggests that the N-domains are flexible. Removal of the C-terminal region also reduces ATPase activity. Taken together, our data suggest that the conformation of the N-domain in relation to the D1-D2 hexamer is directly linked to ATP hydrolysis and that the C-terminal region is required for hexamer stability. This leads us to propose a model where the N-domain adopts either of two conformations: a flexible conformation compatible with ATP hydrolysis or a coplanar conformation that is inactive. PMID:22270372

Scanning electron microscopy observations of failures of implant overdenture bars: a case series report.

PubMed

Waddell, J Neil; Payne, Alan G T; Swain, Michael V; Kieser, Jules A

2010-03-01

Soldered or cast bars are used as a standard of care in attachment systems supporting maxillary and mandibular implant overdentures. When failures of these bars occur, currently there is a lack of evidence in relation to their specific etiology, location, or nature. To investigate the failure process of a case series of six failed soldered bars, four intact soldered bars, and one intact cast milled bar, which had been supporting implant overdentures. A total of 11 different overdenture bars were removed from patients with different configuration of opposing arches. A failed bar (FB) group (n = 6) had failed soldered overdenture bars, which were recovered from patients following up to 2 years of wear before requiring prosthodontic maintenance and repair. An intact bar (IB) group (n = 5) had both soldered bars and a single cast milled bar, which had been worn by patients for 2 to 5 years prior to receiving other aspects of prosthodontic maintenance. All bars were examined using scanning electron microscopy to establish the possible mode of failure (FB) or to identify evidence of potential failure in the future (IB). Evidence of a progressive failure mode of corrosion fatigue and creep were observed on all the FB and IB usually around the solder areas and nonoxidizing gold cylinder. Fatigue and creep were also observed in all the IB. Where the level of corrosion was substantial, there was no evidence of wear from the matrices of the attachment system. Evidence of an instantaneous failure mode, ductile and brittle overload, was observed on the fracture surfaces of all the FB, within the solder and the nonoxidizing gold cylinders, at the solder/cylinder interface. Corrosion, followed by corrosion fatigue, appears to be a key factor in the onset of the failure process for overdenture bars in this case series of both maxillary and mandibular overdentures. Limited sample size and lack of standardization identify trends only but prevent broad interpretation of the findings.

$${{\\bar{d}} - {\\bar{u}}}$$ Flavor Asymmetry in the Proton in Chiral Effective Field Theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salamu, Y.; Ji, Cheung-Ryong; Melnitchouk, Wally

2015-09-01

Themore » $${\\bar d - \\bar u}$$ flavor asymmetry in the proton arising from pion loops is computed using chiral effective field theory. calculation includes both nucleon and Δ intermediate states, and uses both the fully relativistic and heavy baryon frameworks. x dependence of $${\\bar d - \\bar u}$$ extracted from the Fermilab E866 Drell–Yan data can be well reproduced in terms of a single transverse momentum cutoff parameter regulating the ultraviolet behavior of the loop integrals. In addition to the distribution at x > 0, corrections to the integrated asymmetry from zero momentum contributions are computed, which arise from pion rainbow and bubble diagrams at x = 0. These have not been accounted for in previous analyses, and can make important contributions to the lowest moment of $${\\bar d-\\bar u}$$ .« less

Abl N-terminal cap stabilization of SH3 domain dynamics.

PubMed

Chen, Shugui; Dumitrescu, Teodora Pene; Smithgall, Thomas E; Engen, John R

2008-05-27

Crystal structures and other biochemical data indicate that the N-terminal cap (NCap) region of the Abelson tyrosine kinase (c-Abl) is important for maintaining the downregulated conformation of the kinase domain. The exact contributions that the NCap makes in stabilizing the various intramolecular interactions within c-Abl are less clear. While the NCap appears to be important for locking the SH3 and SH2 domains to the back of the kinase domain, there may be other more subtle elements of regulation. Hydrogen exchange (HX) and mass spectrometry (MS) were used to determine if the NCap contributes to intramolecular interactions involving the Abl SH3 domain. Under physiological conditions, the Abl SH3 domain underwent partial unfolding and its unfolding half-life was slowed during binding to the SH2 kinase linker, providing a unique assay for testing NCap-induced stabilization of the SH3 domain in various constructs. The results showed that the NCap stabilizes the dynamics of the SH3 domain in certain constructs but does not increase the relative affinity of the SH3 domain for the native SH2 kinase linker. The stabilization effect was absent in constructs of just the NCap and SH3 but was obvious when the SH2 domain and the SH2 kinase linker were present. These results suggest that interactions between the NCap and the SH3 domain can contribute to c-Abl stabilization in constructs that contain at least the SH2 domain, an effect that may partially compensate for the absence of the negative regulatory C-terminal tail found in the related Src family of kinases.

A Review of the Biomechanical Differences Between the High-Bar and Low-Bar Back-Squat.

PubMed

Glassbrook, Daniel J; Helms, Eric R; Brown, Scott R; Storey, Adam G

2017-09-01

Glassbrook, DJ, Helms, ER, Brown, SR, and Storey, AG. A review of the biomechanical differences between the high-bar and low-bar back-squat. J Strength Cond Res 31(9): 2618-2634, 2017-The back-squat is a common exercise in strength and conditioning for a variety of sports. It is widely regarded as a fundamental movement to increase and measure lower-body and trunk function, as well as an effective injury rehabilitation exercise. There are typically 2 different bar positions used when performing the back-squat: the traditional "high-bar" back-squat (HBBS) and the "low-bar" back-squat (LBBS). Different movement strategies are used to ensure that the center of mass remains in the base of support for balance during the execution of these lifts. These movement strategies manifest as differences in (a) joint angles, (b) vertical ground reaction forces, and (c) the activity of key muscles. This review showed that the HBBS is characterized by greater knee flexion, lesser hip flexion, a more upright torso, and a deeper squat. The LBBS is characterized by greater hip flexion and, therefore, a greater forward lean. However, there are limited differences in vertical ground reaction forces between the HBBS and LBBS. The LBBS can also be characterized by a greater muscle activity of the erector spinae, adductors, and gluteal muscles, whereas the HBBS can be characterized by greater quadriceps muscle activity. Practitioners seeking to develop the posterior-chain hip musculature (i.e., gluteal, hamstring, and erector muscle groups) may seek to use the LBBS. In comparison, those seeking to replicate movements with a more upright torso and contribution from the quadriceps may rather seek to use the HBBS in training.

An intervention study on the effect of matcha tea, in drink and snack bar formats, on mood and cognitive performance.

PubMed

Dietz, Christina; Dekker, Matthijs; Piqueras-Fiszman, Betina

2017-09-01

Matcha tea is gaining popularity throughout the world in recent years and is frequently referred to as a mood-and-brain food. Previous research has demonstrated that three constituents present in matcha tea, l-theanine, epigallocatechin gallate (EGCG), and caffeine, affect mood and cognitive performance. However, to date there are no studies assessing the effect of matcha tea itself. The present study investigates these effects by means of a human intervention study administering matcha tea and a matcha containing product. Using a randomized, placebo-controlled, single-blind study, 23 consumers participated in four test sessions. In each session, participants consumed one of the four test products: matcha tea, matcha tea bar (each containing 4g matcha tea powder), placebo tea, or placebo bar. The assessment was performed at baseline and 60min post-treatment. The participants performed a set of cognitive tests assessing attention, information processing, working memory, and episodic memory. The mood state was measured by means of a Profile of Mood States (POMS). After consuming the matcha products compared to placebo versions, there were mainly significant improvements in tasks measuring basic attention abilities and psychomotor speed in response to stimuli over a defined period of time. In contrast to expectations, the effect was barely present in the other cognitive tasks. The POMS results revealed no significant changes in mood. The influence of the food matrix was demonstrated by the fact that on most cognitive performance measures the drink format outperformed the bar format, particularly in tasks measuring speed of spatial working memory and delayed picture recognition. This study suggests that matcha tea consumed in a realistic dose can induce slight effects on speed of attention and episodic secondary memory to a low degree. Further studies are required to elucidate the influences of the food matrix. Copyright © 2017 Elsevier Ltd. All rights reserved.

Measurement of the forward-backward asymmetry of $$\\Lambda$$ and $$\\bar{\\Lambda}$$ production in $$p \\bar{p}$$ collisions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abazov, Victor Mukhamedovich

Here, we studymore » $$\\Lambda$$ and $$\\bar{\\Lambda}$$ production asymmetries in $$p \\bar{p} \\rightarrow \\Lambda (\\bar{\\Lambda}) X$$, $$p \\bar{p} \\rightarrow J/\\psi \\Lambda (\\bar{\\Lambda}) X$$, and $$p \\bar{p} \\rightarrow \\mu^\\pm \\Lambda (\\bar{\\Lambda}) X$$ events recorded by the D0 detector at the Fermilab Tevatron collider at $$\\sqrt{s} = 1.96$$ TeV. We find an excess of $$\\Lambda$$'s ($$\\bar{\\Lambda}$$'s) produced in the proton (antiproton) direction. This forward-backward asymmetry is measured as a function of rapidity. We confirm that the $$\\bar{\\Lambda}/\\Lambda$$ production ratio, measured by several experiments with various targets and a wide range of energies, is a universal function of "rapidity loss", i.e., the rapidity difference of the beam proton and the lambda.« less

Measurement of the forward-backward asymmetry of $$\\Lambda$$ and $$\\bar{\\Lambda}$$ production in $$p \\bar{p}$$ collisions

DOE PAGES

Abazov, Victor Mukhamedovich

2016-02-09

Here, we studymore » $$\\Lambda$$ and $$\\bar{\\Lambda}$$ production asymmetries in $$p \\bar{p} \\rightarrow \\Lambda (\\bar{\\Lambda}) X$$, $$p \\bar{p} \\rightarrow J/\\psi \\Lambda (\\bar{\\Lambda}) X$$, and $$p \\bar{p} \\rightarrow \\mu^\\pm \\Lambda (\\bar{\\Lambda}) X$$ events recorded by the D0 detector at the Fermilab Tevatron collider at $$\\sqrt{s} = 1.96$$ TeV. We find an excess of $$\\Lambda$$'s ($$\\bar{\\Lambda}$$'s) produced in the proton (antiproton) direction. This forward-backward asymmetry is measured as a function of rapidity. We confirm that the $$\\bar{\\Lambda}/\\Lambda$$ production ratio, measured by several experiments with various targets and a wide range of energies, is a universal function of "rapidity loss", i.e., the rapidity difference of the beam proton and the lambda.« less

What makes the family of barred disc galaxies so rich: damping stellar bars in spinning haloes

NASA Astrophysics Data System (ADS)

Collier, Angela; Shlosman, Isaac; Heller, Clayton

2018-05-01

We model and analyse the secular evolution of stellar bars in spinning dark matter (DM) haloes with the cosmological spin λ ˜ 0-0.09. Using high-resolution stellar and DM numerical simulations, we focus on angular momentum exchange between stellar discs and DM haloes of various axisymmetric shapes - spherical, oblate, and prolate. We find that stellar bars experience a diverse evolution that is guided by the ability of parent haloes to absorb angular momentum, J, lost by the disc through the action of gravitational torques, resonant and non-resonant. We confirm that dynamical bar instability is accelerated via resonant J-transfer to the halo. Our main findings relate to the long-term secular evolution of disc-halo systems: with an increasing λ, bars experience less growth and basically dissolve after they pass through vertical buckling instability. Specifically, with increasing λ, (1) the vertical buckling instability in stellar bars colludes with inability of the inner halo to absorb J - this emerges as the main factor weakening or destroying bars in spinning haloes; (2) bars lose progressively less J, and their pattern speeds level off; (3) bars are smaller, and for λ ≳ 0.06 cease their growth completely following buckling; (4) bars in λ > 0.03 haloes have ratio of corotation-to-bar radii, RCR/Rb > 2, and represent so-called slow bars without offset dust lanes. We provide a quantitative analysis of J-transfer in disc-halo systems, and explain the reasons for absence of growth in fast spinning haloes and its observational corollaries. We conclude that stellar bar evolution is substantially more complex than anticipated, and bars are not as resilient as has been considered so far.

Performance of the SciBar cosmic ray telescope (SciCRT) toward the detection of high-energy solar neutrons in solar cycle 24

NASA Astrophysics Data System (ADS)

Sasai, Yoshinori; Nagai, Yuya; Itow, Yoshitaka; Matsubara, Yutaka; Sako, Takashi; Lopez, Diego; Itow, Tsukasa; Munakata, Kazuoki; Kato, Chihiro; Kozai, Masayoshi; Miyazaki, Takahiro; Shibata, Shoichi; Oshima, Akitoshi; Kojima, Hiroshi; Tsuchiya, Harufumi; Watanabe, Kyoko; Koi, Tatsumi; Valdés-Galicia, Jose Francisco; González, Luis Xavier; Ortiz, Ernesto; Musalem, Octavio; Hurtado, Alejandro; Garcia, Rocio; Anzorena, Marcos

2014-12-01

We plan to observe solar neutrons at Mt. Sierra Negra (4,600 m above sea level) in Mexico using the SciBar detector. This project is named the SciBar Cosmic Ray Telescope (SciCRT). The main aims of the SciCRT project are to observe solar neutrons to study the mechanism of ion acceleration on the surface of the sun and to monitor the anisotropy of galactic cosmic-ray muons. The SciBar detector, a fully active tracker, is composed of 14,848 scintillator bars, whose dimension is 300 cm × 2.5 cm × 1.3 cm. The structure of the detector enables us to obtain the particle trajectory and its total deposited energy. This information is useful for the energy reconstruction of primary neutrons and particle identification. The total volume of the detector is 3.0 m × 3.0 m × 1.7 m. Since this volume is much larger than the solar neutron telescope (SNT) in Mexico, the detection efficiency of the SciCRT for neutrons is highly enhanced. We performed the calibration of the SciCRT at Instituto Nacional de Astrofisica, Optica y Electronica (INAOE) located at 2,150 m above sea level in Mexico in 2012. We installed the SciCRT at Mt. Sierra Negra in April 2013 and calibrated this detector in May and August 2013. We started continuous observation in March 2014. In this paper, we report the detector performance as a solar neutron telescope and the current status of the SciCRT.

Secular Evolution in Barred Galaxies: Observations

NASA Astrophysics Data System (ADS)

Merrifield, M.

2002-12-01

This paper describes a framework for studying galaxy morphology, particularly bar strength, in a quantitative manner, and presents applications of this approach that reveal observational evidence for secular evolution in bar morphology. The distribution of bar strength in galaxies is quite strongly bimodal, suggesting that barred and unbarred systems are distinct entities, and that any evolution between these two states must occur on a relatively rapid timescale. Bars' strengths appear to be correlated with their pattern speeds, implying that these structures weaken as they start to slow, and disappear entirely before the bars have slowed significantly. There is also tantalizing evidence that bars are rare beyond a redshift of z ~ 0.7, indicating that galaxies have only recently evolved to a point where bars can readily form.

Conformation Changes, N-terminal Involvement, and cGMP Signal Relay in the Phosphodiesterase-5 GAF Domain*

PubMed Central

Wang, Huanchen; Robinson, Howard; Ke, Hengming

2010-01-01

The activity of phosphodiesterase-5 (PDE5) is specific for cGMP and is regulated by cGMP binding to GAF-A in its regulatory domain. To better understand the regulatory mechanism, x-ray crystallographic and biochemical studies were performed on constructs of human PDE5A1 containing the N-terminal phosphorylation segment, GAF-A, and GAF-B. Superposition of this unliganded GAF-A with the previously reported NMR structure of cGMP-bound PDE5 revealed dramatic conformational differences and suggested that helix H4 and strand B3 probably serve as two lids to gate the cGMP-binding pocket in GAF-A. The structure also identified an interfacial region among GAF-A, GAF-B, and the N-terminal loop, which may serve as a relay of the cGMP signal from GAF-A to GAF-B. N-terminal loop 98–147 was physically associated with GAF-B domains of the dimer. Biochemical analyses showed an inhibitory effect of this loop on cGMP binding and its involvement in the cGMP-induced conformation changes. PMID:20861010

Conformation Changes N-terminal Involvement and cGMP Signal Relay in the Phosphodiesterase-5 GAF Domain

DOE Office of Scientific and Technical Information (OSTI.GOV)

H Wang; H Robinson; H Ke

2011-12-31

The activity of phosphodiesterase-5 (PDE5) is specific for cGMP and is regulated by cGMP binding to GAF-A in its regulatory domain. To better understand the regulatory mechanism, x-ray crystallographic and biochemical studies were performed on constructs of human PDE5A1 containing the N-terminal phosphorylation segment, GAF-A, and GAF-B. Superposition of this unliganded GAF-A with the previously reported NMR structure of cGMP-bound PDE5 revealed dramatic conformational differences and suggested that helix H4 and strand B3 probably serve as two lids to gate the cGMP-binding pocket in GAF-A. The structure also identified an interfacial region among GAF-A, GAF-B, and the N-terminal loop, whichmore » may serve as a relay of the cGMP signal from GAF-A to GAF-B. N-terminal loop 98-147 was physically associated with GAF-B domains of the dimer. Biochemical analyses showed an inhibitory effect of this loop on cGMP binding and its involvement in the cGMP-induced conformation changes.« less

Preparation of polydimethylsiloxane/beta-cyclodextrin/divinylbenzene coated "dumbbell-shaped" stir bar and its application to the analysis of polycyclic aromatic hydrocarbons and polycyclic aromatic sulfur heterocycles compounds in lake water and soil by high performance liquid chromatography.

PubMed

Yu, Chunhe; Yao, Zhimin; Hu, Bin

2009-05-08

A "dumbbell-shaped" stir bar was proposed to prevent the friction loss of coating during the stirring process, and thus prolonged the lifetime of stir bars. The effects of the coating components, including polydimethylsiloxane (PDMS), beta-cyclodextrin (beta-CD) and divinylbenzene (DVB) were investigated according to an orthogonal experimental design, using three polycyclic aromatic hydrocarbons (PAHs) and four polycyclic aromatic sulfur heterocycles (PASHs) as model analytes. Four kinds of stir bars coated with PDMS, PDMS/beta-CD, PDMS/DVB and PDMS/beta-CD/DVB were prepared and their extraction efficiencies for the target compounds were compared. It was demonstrated that PDMS/beta-CD/DVB-coated stir bar showed the best affinity to the studied compounds. The preparation reproducibility of PDMS/beta-CD/DVB-coated stir bar ranged from 3.2% to 15.2% (n = 6) in one batch, and 5.2% to 13.4% (n = 6) among batches. The "dumbbell-shaped" stir bar could be used for about 40 times, which were 10 extractions more than a normal stir bar. The prepared PDMS/beta-CD/DVB-coated "dumbbell-shaped" stir bar was used for stir bar sorptive extraction (SBSE) of PAHs and PASHs and the desorbed solution was introduced into HPLC-UV for subsequent analysis. The limits of detection of the proposed method for seven target analytes ranged from 0.007 to 0.103 microg L(-1), the relative standard deviations were in the range of 6.3-12.9% (n = 6, c = 40 microg L(-1)), and the enrichment factors were 19-86. The proposed method was successfully applied to the analysis of seven target analytes in lake water and soil samples.

N-domain angiotensin-I converting enzyme is expressed in immortalized mesangial, proximal tubule and collecting duct cells.

PubMed

Mei Wang, Pamella Huey; Andrade, Maria Claudina; Quinto, Beata Marie Redublo; Di Marco, Giovana; Mortara, Renato Arruda; Vio, Carlos P; Casarini, Dulce Elena

2015-01-01

Somatic ACE (sACE) is found in glomerulus, proximal tubule and excreted in urine. We hypothesized that N-domain ACE can also be found at these sites. ACE profile was analyzed in mesangial (IMC), proximal (LLC-PK1), distal tubule (MDCK) and collecting duct (IMCD) cells. Cell lysate and culture medium were submitted to gel filtration chromatography, which separated two peaks with ACE activity from cells and medium, except from distal tubule. The first had a high molecular weight and the second, a lower one (65 kDa; N-domain ACE). We focused on N-domain ACE purification and characterization from LLC-PK1. Total LLC-PK1 N-domain ACE purification was achieved by ion-exchange chromatography, which presented only one peak with ACE activity, denominated ACE(int2A). ACE(int2A) activity was influenced by pH, NaCl and temperature. The purified enzyme was inhibited by Captopril and hydrolyzed AngI, Ang1-7 and AcSDKP. Its ability to hydrolyze AcSDKP characterized it as an N-domain ACE. ACE(int2A) also presented high amino acid sequence homology with the N-terminal part of sACE from mouse, rat, human and rabbit. The presence of secreted and intracellular N-domain ACE and sACE in IMC, LLC-PK1 and IMCD cells confirmed our studies along the nephron. We identified, purified and characterized N-domain ACE from LLC-PK1. Copyright © 2014 Elsevier B.V. All rights reserved.

Investigation of dowel bar placement accuracy with a dowel bar inserter

DOT National Transportation Integrated Search

2003-05-01

Dowel bar inserters (DBI) on concrete paving equipment eliminate the need for manually placing dowel bar baskets. Reduced manual labor eventually pays off the initial investment in a DBI and ultimately results in reduced PCCP costs to the roadway own...

Stress-strain relationship of high-strength steel (HSS) reinforcing bars

NASA Astrophysics Data System (ADS)

Anggraini, Retno; Tavio, Raka, I. Gede Putu; Agustiar

2018-05-01

The introduction of High-Strength Steel (HSS) reinforcing bars in reinforced concrete members has gained much attention in recent years and led to many advantages such as construction timesaving. It is also more economical since it can reduce the amount of reinforcing steel bars used in concrete members which in turn alleviates the congestion of reinforcement. Up to present, the building codes, e.g. American Concrete Institute (ACI) 318M-14 and Standard National Indonesia (SNI) 2847:2013, still restrict the use of higher-strength steel reinforcing bars for concrete design up to Grade 420 MPa due to the possible suspected brittle behavior of concrete members. This paper evaluates the characteristics of stress-strain relationships of HSS bars if they are comparable to the characteristics of those of Grade 420 MPa. To achieve the objective of the study, a series of steel bars from various grades (420, 550, 650, and 700 MPa) was selected. Tensile tests of these steel samples were conducted under displacement-controlled mode to capture the complete stress-strain curves and particularly the post-yield response of the steel bars. The results indicate that all the steel bars tested had the actual yield strengths greater than the corresponding specified values. The stress-strain curves of HSS reinforcing bars (Grade 550, 650, and 700 MPa) performed slightly different characteristics with those of Grade 420 MPa.

N-terminal domains of human DNA polymerase lambda promote primer realignment during translesion DNA synthesis

PubMed Central

Taggart, David J.; Dayeh, Daniel M.; Fredrickson, Saul W.; Suo, Zucai

2014-01-01

The X-family DNA polymerases λ (Polλ) and β (Polβ) possess similar 5′-2-deoxyribose-5-phosphatelyase (dRPase) and polymerase domains. Besides these domains, Polλ also possesses a BRCA1 C-terminal (BRCT) domain and a proline-rich domain at its N terminus. However, it is unclear how these non-enzymatic domains contribute to the unique biological functions of Polλ. Here, we used primer extension assays and a newly developed high-throughput short oligonucleotide sequencing assay (HT-SOSA) to compare the efficiency of lesion bypass and fidelity of human Polβ, Polλ and two N-terminal deletion constructs of Polλ during the bypass of either an abasic site or a 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG) lesion. We demonstrate that the BRCT domain of Polλ enhances the efficiency of abasic site bypass by approximately 1.6-fold. In contrast, deletion of the N-terminal domains of Polλ did not affect the efficiency of 8-oxodG bypass relative to nucleotide incorporations opposite undamaged dG. HT-SOSA analysis demonstrated that Polλ and Polβ preferentially generated −1 or −2 frameshift mutations when bypassing an abasic site and the single or double base deletion frequency was highly sequence dependent. Interestingly, the BRCT and proline-rich domains of Polλ cooperatively promoted the generation of −2 frameshift mutations when the abasic site was situated within a sequence context that was susceptible to homology-driven primer realignment. Furthermore, both N-terminal domains of Polλ increased the generation of −1 frameshift mutations during 8-oxodG bypass and influenced the frequency of substitution mutations produced by Polλ opposite the 8-oxodG lesion. Overall, our data support a model wherein the BRCT and proline-rich domains of Polλ act cooperatively to promote primer/template realignment between DNA strands of limited sequence homology. This function of the N-terminal domains may facilitate the role of Polλ as a gap-filling polymerase

High Performance Computing of Meshless Time Domain Method on Multi-GPU Cluster

NASA Astrophysics Data System (ADS)

Ikuno, Soichiro; Nakata, Susumu; Hirokawa, Yuta; Itoh, Taku

2015-01-01

High performance computing of Meshless Time Domain Method (MTDM) on multi-GPU using the supercomputer HA-PACS (Highly Accelerated Parallel Advanced system for Computational Sciences) at University of Tsukuba is investigated. Generally, the finite difference time domain (FDTD) method is adopted for the numerical simulation of the electromagnetic wave propagation phenomena. However, the numerical domain must be divided into rectangle meshes, and it is difficult to adopt the problem in a complexed domain to the method. On the other hand, MTDM can be easily adept to the problem because MTDM does not requires meshes. In the present study, we implement MTDM on multi-GPU cluster to speedup the method, and numerically investigate the performance of the method on multi-GPU cluster. To reduce the computation time, the communication time between the decomposed domain is hided below the perfect matched layer (PML) calculation procedure. The results of computation show that speedup of MTDM on 128 GPUs is 173 times faster than that of single CPU calculation.

Overlapping and Specific Functions of the Hsp104 N Domain Define Its Role in Protein Disaggregation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Jungsoon; Sung, Nuri; Mercado, Jonathan M.

Hsp104 is a ring-forming protein disaggregase that rescues stress-damaged proteins from an aggregated state. To facilitate protein disaggregation, Hsp104 cooperates with Hsp70 and Hsp40 chaperones (Hsp70/40) to form a bi-chaperone system. How Hsp104 recognizes its substrates, particularly the importance of the N domain, remains poorly understood and multiple, seemingly conficting mechanisms have been proposed. Although the N domain is dispensable for protein disaggregation, it is sensitive to point mutations that abolish the function of the bacterial Hsp104 homolog in vitro, and is essential for curing yeast prions by Hsp104 overexpression in vivo. Here, we present the crystal structure of anmore » N-terminal fragment of Saccharomyces cerevisiae Hsp104 with the N domain of one molecule bound to the C-terminal helix of the neighboring D1 domain. Consistent with mimicking substrate interaction, mutating the putative substrate-binding site in a constitutively active Hsp104 variant impairs the recovery of functional protein from aggregates. We fnd that the observed substrate-binding defect can be rescued by Hsp70/40 chaperones, providing a molecular explanation as to why the N domain is dispensable for protein disaggregation when Hsp70/40 is present, yet essential for the dissolution of Hsp104-specifc substrates, such as yeast prions, which likely depends on a direct N domain interaction.« less

Overlapping and Specific Functions of the Hsp104 N Domain Define Its Role in Protein Disaggregation

DOE PAGES

Lee, Jungsoon; Sung, Nuri; Mercado, Jonathan M.; ...

2017-09-11

Hsp104 is a ring-forming protein disaggregase that rescues stress-damaged proteins from an aggregated state. To facilitate protein disaggregation, Hsp104 cooperates with Hsp70 and Hsp40 chaperones (Hsp70/40) to form a bi-chaperone system. How Hsp104 recognizes its substrates, particularly the importance of the N domain, remains poorly understood and multiple, seemingly conficting mechanisms have been proposed. Although the N domain is dispensable for protein disaggregation, it is sensitive to point mutations that abolish the function of the bacterial Hsp104 homolog in vitro, and is essential for curing yeast prions by Hsp104 overexpression in vivo. Here, we present the crystal structure of anmore » N-terminal fragment of Saccharomyces cerevisiae Hsp104 with the N domain of one molecule bound to the C-terminal helix of the neighboring D1 domain. Consistent with mimicking substrate interaction, mutating the putative substrate-binding site in a constitutively active Hsp104 variant impairs the recovery of functional protein from aggregates. We fnd that the observed substrate-binding defect can be rescued by Hsp70/40 chaperones, providing a molecular explanation as to why the N domain is dispensable for protein disaggregation when Hsp70/40 is present, yet essential for the dissolution of Hsp104-specifc substrates, such as yeast prions, which likely depends on a direct N domain interaction.« less

Predicting vertical jump height from bar velocity.

PubMed

García-Ramos, Amador; Štirn, Igor; Padial, Paulino; Argüelles-Cienfuegos, Javier; De la Fuente, Blanca; Strojnik, Vojko; Feriche, Belén

2015-06-01

The objective of the study was to assess the use of maximum (Vmax) and final propulsive phase (FPV) bar velocity to predict jump height in the weighted jump squat. FPV was defined as the velocity reached just before bar acceleration was lower than gravity (-9.81 m·s(-2)). Vertical jump height was calculated from the take-off velocity (Vtake-off) provided by a force platform. Thirty swimmers belonging to the National Slovenian swimming team performed a jump squat incremental loading test, lifting 25%, 50%, 75% and 100% of body weight in a Smith machine. Jump performance was simultaneously monitored using an AMTI portable force platform and a linear velocity transducer attached to the barbell. Simple linear regression was used to estimate jump height from the Vmax and FPV recorded by the linear velocity transducer. Vmax (y = 16.577x - 16.384) was able to explain 93% of jump height variance with a standard error of the estimate of 1.47 cm. FPV (y = 12.828x - 6.504) was able to explain 91% of jump height variance with a standard error of the estimate of 1.66 cm. Despite that both variables resulted to be good predictors, heteroscedasticity in the differences between FPV and Vtake-off was observed (r(2) = 0.307), while the differences between Vmax and Vtake-off were homogenously distributed (r(2) = 0.071). These results suggest that Vmax is a valid tool for estimating vertical jump height in a loaded jump squat test performed in a Smith machine. Key pointsVertical jump height in the loaded jump squat can be estimated with acceptable precision from the maximum bar velocity recorded by a linear velocity transducer.The relationship between the point at which bar acceleration is less than -9.81 m·s(-2) and the real take-off is affected by the velocity of movement.Mean propulsive velocity recorded by a linear velocity transducer does not appear to be optimal to monitor ballistic exercise performance.

Predicting Vertical Jump Height from Bar Velocity

PubMed Central

García-Ramos, Amador; Štirn, Igor; Padial, Paulino; Argüelles-Cienfuegos, Javier; De la Fuente, Blanca; Strojnik, Vojko; Feriche, Belén

2015-01-01

The objective of the study was to assess the use of maximum (Vmax) and final propulsive phase (FPV) bar velocity to predict jump height in the weighted jump squat. FPV was defined as the velocity reached just before bar acceleration was lower than gravity (-9.81 m·s-2). Vertical jump height was calculated from the take-off velocity (Vtake-off) provided by a force platform. Thirty swimmers belonging to the National Slovenian swimming team performed a jump squat incremental loading test, lifting 25%, 50%, 75% and 100% of body weight in a Smith machine. Jump performance was simultaneously monitored using an AMTI portable force platform and a linear velocity transducer attached to the barbell. Simple linear regression was used to estimate jump height from the Vmax and FPV recorded by the linear velocity transducer. Vmax (y = 16.577x - 16.384) was able to explain 93% of jump height variance with a standard error of the estimate of 1.47 cm. FPV (y = 12.828x - 6.504) was able to explain 91% of jump height variance with a standard error of the estimate of 1.66 cm. Despite that both variables resulted to be good predictors, heteroscedasticity in the differences between FPV and Vtake-off was observed (r2 = 0.307), while the differences between Vmax and Vtake-off were homogenously distributed (r2 = 0.071). These results suggest that Vmax is a valid tool for estimating vertical jump height in a loaded jump squat test performed in a Smith machine. Key points Vertical jump height in the loaded jump squat can be estimated with acceptable precision from the maximum bar velocity recorded by a linear velocity transducer. The relationship between the point at which bar acceleration is less than -9.81 m·s-2 and the real take-off is affected by the velocity of movement. Mean propulsive velocity recorded by a linear velocity transducer does not appear to be optimal to monitor ballistic exercise performance. PMID:25983572

Mechanisms linking sediment supply and bar morphology: Results from a straight flume with alternate bars

NASA Astrophysics Data System (ADS)

Braudrick, C. A.; Minear, J. T.; Dietrich, W. E.; Dehart, M.; Sklar, L. S.

2008-12-01

One of the largest uncertainties in routing sediment through drainage networks is predicting the degree to which changes in sediment supply are mitigated by changes in sediment storage in bars. We hypothesize that changes in topographic steering link sediment supply and bar morphology. This hypothesis posits that increased sediment supply would enhance topographic steering over the bar, causing the bar to advance laterally into the pool. Contrarily, decreased supply would diminish topographic steering, causing bars to shrink laterally and pools to expand. We examined this hypothesis in a 28-m long, 0.86-m wide flume with a constant discharge of 5.4 l/s and sand with a median grain size of 0.8 mm. The conditions were sufficient to support alternate bars downstream of the upper 8-10 m, and the flume was run for approximately 65 hours at a constant discharge and sediment feed. The equilibrium slope was 0.0033. Once the channel reached equilibrium, the sediment feed was turned off while the discharge was held constant. During the first 25 hours after the feed was stopped, the sediment transport rate at the downstream end of the flume increased from 9.8 to 10.5 kg/hr as sediment was provided by incision at the upstream end of the flume. Because the bed was the only sediment source, sediment supply increased with distance down the flume. Once the feed was shut off, bar response differed between the upstream and downstream portions of the flume. Bars at the downstream end of the flume, where sediment supply increased relative to equilibrium conditions, swelled into the pool. These changes in bar morphology were accompanied by a decrease in surface grain size. Further upstream, where sediment supply was lower, the bars shrunk. These results suggest that there may be a linkage between topographic steering, bar morphology, and sediment supply, but further numerical tests and experimental manipulations are necessary to verify this linkage and to account for the effect of the

Deletion of the N-terminal Domain (NTD) Alters the Ethanol Inhibition of NMDA Receptors in a Subunit-Dependent Manner

PubMed Central

Smothers, C. Thetford; Jin, Chun; Woodward, John J.

2013-01-01

Background Ethanol inhibition of NMDA receptors is poorly understood due in part to the organizational complexity of the receptor that provides ample locations for sites of action. Among these the N-terminal domain of NMDA receptor subunits contains binding sites for a variety of modulatory agents including zinc, protons and GluN2B selective antagonists such as ifenprodil or Ro-25–6981. Ethanol inhibition of neuronal NMDA receptors expressed in some brain areas has been reported to be occluded by the presence of ifenprodil or similar compounds suggesting that the N-terminal domain may be important in regulating the ethanol sensitivity of NMDA receptors. Methods Wild-type GluN1 and GluN2 subunits and those in which the coding sequence for the N-terminal domain was deleted were expressed in HEK293 cells. Whole-cell voltage-clamp recording was used to assess ethanol inhibition of wild-type and mutant receptors lacking the N-terminal domain. Results As compared to wild-type GluN1/GluN2A receptors, ethanol inhibition was slightly greater in cells expressing GluN2A subunits lacking the N-terminal domain. In contrast, GluN2B N-terminal deletion mutants showed normal ethanol inhibition while those lacking the N-terminal domain in both GluN1 and GluN2B subunits had decreased ethanol inhibition as compared to wild-type receptors. N-terminal domain lacking GluN2B receptors were insensitive to ifenprodil but retained normal sensitivity to ethanol. Conclusions These findings indicate that the N-terminal domain modestly influences the ethanol sensitivity of NMDA receptors in a subunit-dependent manner. They also show that ifenprodil’s actions on GluN2B containing receptors can be dissociated from those of ethanol. These results suggest that while the N-terminal domain is not a primary site of action for ethanol on NMDA receptors, it likely affects sensitivity via actions on intrinsic channel properties. PMID:23905549

Glucose effects on long-term memory performance: duration and domain specificity.

PubMed

Owen, Lauren; Finnegan, Yvonne; Hu, Henglong; Scholey, Andrew B; Sünram-Lea, Sandra I

2010-08-01

Previous research has suggested that long-term verbal declarative memory is particularly sensitive to enhancement by glucose loading; however, investigation of glucose effects on certain memory domains has hitherto been neglected. Therefore, domain specificity of glucose effects merits further elucidation. The aim of the present research was to provide a more comprehensive investigation of the possible effects of glucose administration on different aspects of memory by 1) contrasting the effect of glucose administration on different memory domains (implicit/explicit memory; verbal/non-verbal memory, and recognition/familiarity processes), 2) investigating whether potential effects on memory domains differ depending on the dose of glucose administered (25 g versus 60 g), 3) exploring the duration of the glucose facilitation effect (assessment of memory performance 35 min and 1 week after encoding). A double-blind between-subjects design was used to test the effects of administration of 25 and 60 g glucose on memory performance. Implicit memory was improved following administration of 60 g of glucose. Glucose supplementation failed to improve face recognition performance but significantly improved performance of word recall and recognition following administration of 60 g of glucose. However, effects were not maintained 1 week following encoding. Improved implicit memory performance following glucose administration has not been reported before. Furthermore, the current data tentatively suggest that level of processing may determine the required glucose dosage to demonstrate memory improvement and that higher dosages may be able to exert effects on memory pertaining to both hippocampal and non-hippocampal brain regions.

Arch bar stabilization of endotracheal tubes in children with facial burns.

PubMed

Perrotta, V J; Stern, J D; Lo, A K; Mitra, A

1995-01-01

Endotracheal tube stabilization in children with facial burns can be difficult. Several methods rely on straps or complex devices that apply undesirable pressure to the face, potentially destroying skin grafts and making wound care difficult. Techniques that rely on a single wire or suture can be unreliable. Presented here is the arch bar method of endotracheal tube stabilization, which appears to be free of these problems. This method employs a standard dental arch bar secured to four maxillary teeth with 24-gauge stainless steel wire. The endotracheal tube is anchored to the arch bar with two pieces of wire or suture material. The arch bar method of endotracheal tube stabilization was used on three patients in the burn center at St. Christopher's Hospital for Children. Wound care and successful skin grafting were performed without difficulty. No complications related to the arch bars occurred.

Customized mandibular reconstruction plates improve mechanical performance in a mandibular reconstruction model

PubMed Central

Gutwald, Ralf; Jaeger, Raimund; Lambers, Floor M.

2017-01-01

Abstract The purpose of this paper was to analyze the biomechanical performance of customized mandibular reconstruction plates with optimized strength. The best locations for increasing bar widths were determined with a sensitivity analysis. Standard and customized plates were mounted on mandible models and mechanically tested. Maximum stress in the plate could be reduced from 573 to 393 MPa (−31%) by increasing bar widths. The median fatigue limit was significantly greater (p < 0.001) for customized plates (650 ± 27 N) than for standard plates (475 ± 27 N). Increasing bar widths at case-specific locations was an effective strategy for increasing plate fatigue performance. PMID:27887036

Release of iron, zinc, and lead from common iron construction bars and zinc metallic bars in water solutions and meals.

PubMed

Lechtig, Aarón; Lòpez de Romaña, Daniel; Boy, Erick; Vargas, Alejandro; Rosas del Portal, Mauricio; Huaylinos, María Luisa

2007-12-01

The use of iron pots has decreased the prevalence of anemia. To investigate the release of iron, zinc, and lead from metallic iron and zinc bars incubated in water and in meals. Iron, zinc, and lead concentrations were measured at different incubation conditions in water and in meals. The iron concentration in water was 1.26 mg/L after incubation with one iron bar at pH 7 and 100 degrees C for 20 minutes and in meals was 0.97 mg per 100 g of wet meals, rich in phytate, cooking at 100 degrees C during 20 minutes. The maximum contents were 7720 mg/L of iron and 1826 mg/L of zinc in vinegar at pH 3 and 20 degrees C after 90 and 32 days, respectively. Lead was released from the bars, but at concentrations well below the upper tolerable limits. In outreach populations, the use of iron and zinc metallic bars in water and meals could contribute to sustainable, very low-cost prevention of iron and zinc deficiencies, and home-fortified vinegar could be used for treatment of both deficiencies. Field trials should be performed to determine the impact that the use of iron and zinc metallic bars in water and meals might have on the iron and zinc status of population groups.

Numerical simulations of wave propagation in long bars with application to Kolsky bar testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Corona, Edmundo

2014-11-01

Material testing using the Kolsky bar, or split Hopkinson bar, technique has proven instrumental to conduct measurements of material behavior at strain rates in the order of 10 3 s -1. Test design and data reduction, however, remain empirical endeavors based on the experimentalist's experience. Issues such as wave propagation across discontinuities, the effect of the deformation of the bar surfaces in contact with the specimen, the effect of geometric features in tensile specimens (dog-bone shape), wave dispersion in the bars and other particulars are generally treated using simplified models. The work presented here was conducted in Q3 and Q4more » of FY14. The objective was to demonstrate the feasibility of numerical simulations of Kolsky bar tests, which was done successfully.« less

Cryogenic ultra-high power infrared diode laser bars

NASA Astrophysics Data System (ADS)

Crump, Paul; Frevert, C.; Hösler, H.; Bugge, F.; Knigge, S.; Pittroff, W.; Erbert, G.; Tränkle, G.

2014-02-01

GaAs-based high power diode lasers are the most efficient source of optical energy, and are in wide use in industrial applications, either directly or as pump sources for other laser media. Increased output power per laser is required to enable new applications (increased optical power density) and to reduce cost (more output per component leads to lower cost in $/W). For example, laser bars in the 9xx nm wavelength range with the very highest power and efficiency are needed as pump sources for many high-energy-class solid-state laser systems. We here present latest performance progress using a novel design approach that leverages operation at temperatures below 0°C for increases in bar power and efficiency. We show experimentally that operation at -55°C increases conversion efficiency and suppresses thermal rollover, enabling peak quasi-continuous wave bar powers of Pout > 1.6 kW to be achieved (1.2 ms, 10 Hz), limited by the available current. The conversion efficiency at 1.6 kW is 53%. Following on from this demonstration work, the key open challenge is to develop designs that deliver higher efficiencies, targeting > 80% at 1.6 kW. We present an analysis of the limiting factors and show that low electrical resistance is crucial, meaning that long resonators and high fill factor are needed. We review also progress in epitaxial design developments that leverage low temperatures to enable both low resistance and high optical performance. Latest results will be presented, summarizing the impact on bar performance and options for further improvements to efficiency will also be reviewed.

College Students' Exposure to Tobacco Marketing in Nightclubs and Bars

ERIC Educational Resources Information Center

Ridner, S. Lee; Myers, John A.; Hahn, Ellen J.; Ciszewski, Tiffany N.

2010-01-01

Objective: To examine whether a college student's exposure to tobacco marketing in nightclubs and bars was affected by the presence of a smoke-free law. Participants: A random sample (N = 478) of students participated in the survey (no smoke-free law, n = 240; smoke-free law, n = 238). The analysis was limited to students who reported being in…

[Cereal bars with soy protein and wheat germ, physicochemical characteristics and texture during the storage].

PubMed

Castro Freitas, Daniela D G

2005-09-01

Studies analyzing cereal bars have reported on consumer characteristics and preferences in sensory analyses and on their market growth, however little has been published on their physicochemical data and texture properties. Thus the objective of this research was to provide information about the storage of a cereal bar formulation with high protein and vitamin levels based on soy protein and wheat germ, packaged in 3 different films (A: PET/PEBD; B: PETmet/PEBD; C: PET/PEBD/AL/PEBD), during 6 months under environmental conditions of temperature (25 +/- 2 degrees C) and relative humidity (56%). The moisture content, water activity, pH and total acidity of the cereal bars were determined. The textural measurements accompanied during storage were breaking strength, hardness and cohesiveness. The cereal bars presented variations in water activity (Aw), moisture content and total acidity during storage. The moisture content of the bars tended to increase, which led to a significant (p = 0.05) influence on the texture characteristics of breaking strength and hardness, in the different packaging films tested. The increase in the values for breaking strength (A: 4756,5N; B: 5093,0N; C: 5575,6N) at 45 days of storage was attributed to a possible crystallization of the agglutinating syrup used for the bars. The textured soy protein used in the formulation could also have contributed to this fact due to its hygroscopic character, also interfering in the decrease in the cohesiveness measurements (deformation) with time. The effect of the different barrier properties of the packaging films tested was significant (p < 0.05) in the stability of the cereal bars during storage.

Kinematic Properties of Double-barred Galaxies: Simulations versus Integral-field Observations

NASA Astrophysics Data System (ADS)

Du, Min; Debattista, Victor P.; Shen, Juntai; Cappellari, Michele

2016-09-01

Using high-resolution N-body simulations, we recently reported that a dynamically cool inner disk embedded in a hotter outer disk can naturally generate a steady double-barred (S2B) structure. Here we study the kinematics of these S2B simulations, and compare them to integral-field observations from ATLAS 3D and SAURON. We show that S2B galaxies exhibit several distinct kinematic features, namely: (1) significantly distorted isovelocity contours at the transition region between the two bars, (2) peaks in σ LOS along the minor axis of inner bars, which we term “σ-humps,” that are often accompanied by ring/spiral-like features of increased σ LOS, (3) {h}3{--}\\bar{v} anti-correlations in the region of the inner bar for certain orientations, and (4) rings of positive h 4 when viewed at low inclinations. The most impressive of these features are the σ-humps these evolve with the inner bar, oscillating in strength just as the inner bar does as it rotates relative to the outer bar. We show that, in cylindrical coordinates, the inner bar has similar streaming motions and velocity dispersion properties as normal large-scale bars, except for σ z , which exhibits peaks on the minor axis, I.e., humps. These σ z humps are responsible for producing the σ-humps. For three well-resolved early-type S2Bs (NGC 2859, NGC 2950, and NGC 3941) and a potential S2B candidate (NGC 3384), the S2B model qualitatively matches the integral-field data well, including the “σ-hollows” previously identified. We also discuss the kinematic effect of a nuclear disk in S2Bs.

The Role of 2D Circulation in Sand Bar Migration

NASA Astrophysics Data System (ADS)

Splinter, K. D.; Holman, R. A.; Plant, N. G.; Holland, K. T.

2006-12-01

position, sinuosity, and incident wave conditions, over a one-year period of time-exposure images of Palm Beach, Australia. The resulting analysis produces clear links between bar sinuosity and the rate of change of mean bar position, suggesting a 2DH approach should be used when modeling bar migration. Gallagher, E. L., et al. (1998), Observations of sand bar evolution on a natural beach, Journal of Geophysical Research, 103, 3203-3215. Plant, N. G., et al. (in review), A dynamical attractor governs beach response to storms, Journal of Geophysical Research.

Cognitive reserve is not associated with improved performance in all cognitive domains.

PubMed

Lavrencic, Louise M; Churches, Owen F; Keage, Hannah A D

2017-06-08

Cognitive reserve beneficially affects cognitive performance, even into advanced age. However, the benefits afforded by high cognitive reserve may not extend to all cognitive domains. This study investigated whether cognitive reserve differentially affects performance on cognitive tasks, in 521 cognitively healthy individuals aged 60 to 98 years (Mage = 68, SD = 6.22, 287 female); years of education was used to index cognitive reserve. Cognitive performance variables assessed attention, executive functions, verbal memory, motor performance, orientation, perception of emotion, processing speed, and working memory. Bootstrapped regression analyses revealed that cognitive reserve was associated with attention, executive functions, verbal and working memory, and orientation; and not significantly related to emotion perception, processing speed, or motor performance. Cognitive reserve appears to differentially affect individual cognitive domains, which extends current theory that purports benefits for all domains. This finding highlights the possibility of using tests not (or minimally) associated with cognitive reserve, to screen for cognitive impairment and dementia in late life; these tests will likely best track brain health, free of compensatory neural mechanisms.

Bar quenching in gas-rich galaxies

NASA Astrophysics Data System (ADS)

Khoperskov, S.; Haywood, M.; Di Matteo, P.; Lehnert, M. D.; Combes, F.

2018-01-01

Galaxy surveys have suggested that rapid and sustained decrease in the star-formation rate (SFR), "quenching", in massive disk galaxies is frequently related to the presence of a bar. Optical and near-IR observations reveal that nearly 60% of disk galaxies in the local universe are barred, thus it is important to understand the relationship between bars and star formation in disk galaxies. Recent observational results imply that the Milky Way quenched about 9-10 Gyr ago, at the transition between the cessation of the growth of the kinematically hot, old, metal-poor thick disk and the kinematically colder, younger, and more metal-rich thin disk. Although perhaps coincidental, the quenching episode could also be related to the formation of the bar. Indeed the transfer of energy from the large-scale shear induced by the bar to increasing turbulent energy could stabilize the gaseous disk against wide-spread star formation and quench the galaxy. To explore the relation between bar formation and star formation in gas rich galaxies quantitatively, we simulated gas-rich disk isolated galaxies. Our simulations include prescriptions for star formation, stellar feedback, and for regulating the multi-phase interstellar medium. We find that the action of stellar bar efficiently quenches star formation, reducing the star-formation rate by a factor of ten in less than 1 Gyr. Analytical and self-consistent galaxy simulations with bars suggest that the action of the stellar bar increases the gas random motions within the co-rotation radius of the bar. Indeed, we detect an increase in the gas velocity dispersion up to 20-35 km s-1 at the end of the bar formation phase. The star-formation efficiency decreases rapidly, and in all of our models, the bar quenches the star formation in the galaxy. The star-formation efficiency is much lower in simulated barred compared to unbarred galaxies and more rapid bar formation implies more rapid quenching.

Structure and Function of the N-Terminal Domain of the Vesicular Stomatitis Virus RNA Polymerase

PubMed Central

Qiu, Shihong; Ogino, Minako; Luo, Ming

2015-01-01

ABSTRACT Viruses have various mechanisms to duplicate their genomes and produce virus-specific mRNAs. Negative-strand RNA viruses encode their own polymerases to perform each of these processes. For the nonsegmented negative-strand RNA viruses, the polymerase is comprised of the large polymerase subunit (L) and the phosphoprotein (P). L proteins from members of the Rhabdoviridae, Paramyxoviridae, and Filoviridae share sequence and predicted secondary structure homology. Here, we present the structure of the N-terminal domain (conserved region I) of the L protein from a rhabdovirus, vesicular stomatitis virus, at 1.8-Å resolution. The strictly and strongly conserved residues in this domain cluster in a single area of the protein. Serial mutation of these residues shows that many of the amino acids are essential for viral transcription but not for mRNA capping. Three-dimensional alignments show that this domain shares structural homology with polymerases from other viral families, including segmented negative-strand RNA and double-stranded RNA (dsRNA) viruses. IMPORTANCE Negative-strand RNA viruses include a diverse set of viral families that infect animals and plants, causing serious illness and economic impact. The members of this group of viruses share a set of functionally conserved proteins that are essential to their replication cycle. Among this set of proteins is the viral polymerase, which performs a unique set of reactions to produce genome- and subgenome-length RNA transcripts. In this article, we study the polymerase of vesicular stomatitis virus, a member of the rhabdoviruses, which has served in the past as a model to study negative-strand RNA virus replication. We have identified a site in the N-terminal domain of the polymerase that is essential to viral transcription and that shares sequence homology with members of the paramyxoviruses and the filoviruses. Newly identified sites such as that described here could prove to be useful targets in the

Propagation behavior of the stress wave in a hollow Hopkinson transmission bar

NASA Astrophysics Data System (ADS)

Zou, G.; Shen, X.; Guo, C.; Vecchio, K. S.; Jiang, F.

2018-03-01

In order to investigate the stress wave propagation behavior through a hollow elastic bar that is used in a Hopkinson-bar-loaded fracture testing system, three-point bending fracture experiments were performed in such a system. The effects of sample span and diameter and wall thickness of the hollow elastic bar on the stress wave propagation behavior were studied numerically using the software of ANSYS/LS-DYNA. The experimental results demonstrated that the incident, reflected, and transmitted pulses calculated by the finite element method are coincident with those obtained from the Hopkinson-bar-loaded fracture tests. Compared to the solid transmission bar, the amplitude of the transmitted pulse is relatively larger in the hollow transmission bar under the same loading conditions and decreases with increasing wall thickness. On the other hand, when the inside diameter is fixed, the effect of the wall thickness on the stress wave characteristics is more obvious.

Star formation suppression and bar ages in nearby barred galaxies

NASA Astrophysics Data System (ADS)

James, P. A.; Percival, S. M.

2018-03-01

We present new spectroscopic data for 21 barred spiral galaxies, which we use to explore the effect of bars on disc star formation, and to place constraints on the characteristic lifetimes of bar episodes. The analysis centres on regions of heavily suppressed star formation activity, which we term `star formation deserts'. Long-slit optical spectroscopy is used to determine H β absorption strengths in these desert regions, and comparisons with theoretical stellar population models are used to determine the time since the last significant star formation activity, and hence the ages of the bars. We find typical ages of ˜1 Gyr, but with a broad range, much larger than would be expected from measurement errors alone, extending from ˜0.25 to >4 Gyr. Low-level residual star formation, or mixing of stars from outside the `desert' regions, could result in a doubling of these age estimates. The relatively young ages of the underlying populations coupled with the strong limits on the current star formation rule out a gradual exponential decline in activity, and hence support our assumption of an abrupt truncation event.

Magnetic Polarizability of Virtual (s\\bar{s}) and (c\\bar{c}) Pairs in the Nucleon

NASA Astrophysics Data System (ADS)

Filip, Peter

2017-12-01

We suggest 3 P 0 quantum state of virtual (s\\bar{s}) pairs in the nucleon can be polarised by the internal fields permeating the volume of the nucleon (proton or neutron). Due to the quadratic Zeeman interaction, 3 P 0 wavefunction of virtual (q\\bar{q}) pairs acquires the admixture of 1 P 10 quantum state in the magnetic field, which generates the antiparallel polarization of s and \\bar{s} quarks (in the nucleon). Considering the internal magnetic fields of neutron and proton (originating from their measured magnetic dipole moments), we suggest the induced s-quark polarization in the neutron to be of the oposite direction compared to the proton case. We mention the influence of the internal chromo-magnetic fields on the quantum state of (q\\bar{q}) pairs in the nucleon and we discuss also the expected behaviour of virtual (c\\bar{c}) pairs.

Relationships between drinking onset, alcohol use intensity, and nighttime risk behaviors in a college bar district.

PubMed

Thombs, Dennis L; O'Mara, Ryan; Tobler, Amy L; Wagenaar, Alexander C; Clapp, John D

2009-01-01

To identify antecedents of risk behavior events in college bar patrons. In this nighttime field study, self-report data and alcohol intoxication readings were collected from patrons immediately upon exiting bars (n = 618). Multilevel structural equation modeling revealed positive associations between age of drinking onset and both alcohol use intensity in the past year and recent bar-going frequency. In turn, alcohol use intensity in the past year was positively associated with bar-going frequency and intoxication at bar exit. An association between drinking onset and bar-going frequency was mediated by alcohol use intensity in the past year. Discernable paths from age of drinking onset to monthly bar-going frequency and intoxication level after leaving a bar can be identified. The results highlight the critical role of drinking onset in development of college student alcohol abuse. Research is needed to determine whether college bars are environmental pathogens mediating between genetic risk factors and patron risk behavior.

Magnetometry of micro-magnets with electrostatically defined Hall bars

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lachance-Quirion, Dany; Camirand Lemyre, Julien; Bergeron, Laurent

2015-11-30

Micro-magnets are key components for quantum information processing with individual spins, enabling arbitrary rotations and addressability. In this work, characterization of sub-micrometer sized CoFe ferromagnets is performed with Hall bars electrostatically defined in a two-dimensional electron gas. Due to the ballistic nature of electron transport in the cross junction of the Hall bar, anomalies such as the quenched Hall effect appear near zero external magnetic field, thus hindering the sensitivity of the magnetometer to small magnetic fields. However, it is shown that the sensitivity of the diffusive limit can be almost completely restored at low temperatures using a large currentmore » density in the Hall bar of about 10 A/m. Overcoming the size limitation of conventional etched Hall bars with electrostatic gating enables the measurement of magnetization curves of 440 nm wide micro-magnets with a signal-to-noise ratio above 10{sup 3}. Furthermore, the inhomogeneity of the stray magnetic field created by the micro-magnets is directly measured using the gate-voltage-dependent width of the sensitive area of the Hall bar.« less

Blue 450nm high power semiconductor continuous wave laser bars exceeding rollover output power of 80W

NASA Astrophysics Data System (ADS)

König, H.; Lell, A.; Stojetz, B.; Ali, M.; Eichler, C.; Peter, M.; Löffler, A.; Strauss, U.; Baumann, M.; Balck, A.; Malchus, J.; Krause, V.

2018-02-01

Industrial material processing like cutting or welding of metals is rather energy efficient using direct diode or diode pumped solid state lasers. However, many applications cannot be addressed by established infrared laser technology due to fundamental material properties of the workpiece: For example materials like copper or gold have too low absorption in the near infrared wavelength range to be processed efficiently by use of existing high power laser systems. The huge interest to enable high power kW systems with more suitable wavelengths in the blue spectral range triggered the German funded research project 'BLAULAS': Therein the feasibility and capability of CW operating high power laser bars based on the GaN material system was investigated by Osram and Laserline. High performance bars were enabled by defeating fundamental challenges like material quality as well as the chip processes, both of which differ significantly from well-known IR laser bars. The research samples were assembled on actively cooled heat sinks with hard solder technology. For the first time an output power of 98W per bar at 60A drive current was achieved. Conversion efficiency as high as 46% at 50W output power was demonstrated.

Accurate D-bar Reconstructions of Conductivity Images Based on a Method of Moment with Sinc Basis.

PubMed

Abbasi, Mahdi

2014-01-01

Planar D-bar integral equation is one of the inverse scattering solution methods for complex problems including inverse conductivity considered in applications such as Electrical impedance tomography (EIT). Recently two different methodologies are considered for the numerical solution of D-bar integrals equation, namely product integrals and multigrid. The first one involves high computational burden and the other one suffers from low convergence rate (CR). In this paper, a novel high speed moment method based using the sinc basis is introduced to solve the two-dimensional D-bar integral equation. In this method, all functions within D-bar integral equation are first expanded using the sinc basis functions. Then, the orthogonal properties of their products dissolve the integral operator of the D-bar equation and results a discrete convolution equation. That is, the new moment method leads to the equation solution without direct computation of the D-bar integral. The resulted discrete convolution equation maybe adapted to a suitable structure to be solved using fast Fourier transform. This allows us to reduce the order of computational complexity to as low as O (N (2)log N). Simulation results on solving D-bar equations arising in EIT problem show that the proposed method is accurate with an ultra-linear CR.

Performance evaluation of Iowa bridge decks constructed with epoxy-coated reinforcing bars.

DOT National Transportation Integrated Search

2011-08-01

Epoxy coatings have been used on the embedded reinforcing bars of bridge decks since the mid-1970s to : mitigate deterioration caused by chloride-induced corrosion. The use of chloride-based deicers became : common in the early 1960s and caused corro...

N- versus C-domain selectivity of catalytic inactivation of human angiotensin converting enzyme by lisinopril-coupled transition metal chelates.

PubMed

Hocharoen, Lalintip; Joyner, Jeff C; Cowan, J A

2013-12-27

The N- and C-terminal domains of human somatic angiotensin I converting enzyme (sACE-1) demonstrate distinct physiological functions, with resulting interest in the development of domain-selective inhibitors for specific therapeutic applications. Herein, the activity of lisinopril-coupled transition metal chelates was tested for both reversible binding and irreversible catalytic inactivation of each domain of sACE-1. C/N domain binding selectivity ratios ranged from 1 to 350, while rates of irreversible catalytic inactivation of the N- and C-domains were found to be significantly greater for the N-domain, suggesting a more optimal orientation of M-chelate-lisinopril complexes within the active site of the N-domain of sACE-1. Finally, the combined effect of binding selectivity and inactivation selectivity was assessed for each catalyst (double-filter selectivity factors), and several catalysts were found to cause domain-selective catalytic inactivation. The results of this study demonstrate the ability to optimize the target selectivity of catalytic metallopeptides through both binding and catalytic factors (double-filter effect).

Search for tt-bar-Resonances in the Lepton+Jets Final State

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schliephake, Thorsten

2008-11-23

A search for a narrow-width heavy resonance decaying into top quark pairs (X{yields}tt-bar) in pp-bar collisions at {radical}(s) = 1.96 TeV has been performed using data collected with the DOe detector at the Fermilab Tevatron Collider. This analysis considers tt-bar candidate events in the lepton+jets channel using a neural network tagger to identify b-jets and the tt-bar invariant mass distribution to search for evidence of resonant production. The analyzed dataset corresponds to an integrated luminosity of approximately 2.1 fb{sup -1}. We find no evidence for a narrow resonance X decaying to tt-bar. Therefore, we set upper limits on {sigma}{sub X}{center_dot}B(X{yields}tt-bar)more » for different hypothesized resonance masses using a Bayesian approach. Within a topcolor-assisted technicolor model, the existence of a leptophobic Z' boson with mass M{sub Z'}<760 GeV and width {gamma}{sub Z'} = 0.012M{sub Z'} can be excluded at 95% C.L.« less

Shape of LOSVDs in Barred Disks: Implications for Future IFU Surveys

NASA Astrophysics Data System (ADS)

Li, Zhao-Yu; Shen, Juntai; Bureau, Martin; Zhou, Yingying; Du, Min; Debattista, Victor P.

2018-02-01

The shape of line-of-sight velocity distributions (LOSVDs) carries important information about the internal dynamics of galaxies. The skewness of LOSVDs represents their asymmetric deviation from a Gaussian profile. Correlations between the skewness parameter (h 3) and the mean velocity (\\overline{V}) of a Gauss–Hermite series reflect the underlying stellar orbital configurations of different morphological components. Using two self-consistent N-body simulations of disk galaxies with different bar strengths, we investigate {h}3-\\overline{V} correlations at different inclination angles. Similar to previous studies, we find anticorrelations in the disk area, and positive correlations in the bar area when viewed edge-on. However, at intermediate inclinations, the outer parts of bars exhibit anticorrelations, while the core areas dominated by the boxy/peanut-shaped (B/PS) bulges still maintain weak positive correlations. When viewed edge-on, particles in the foreground/background disk (the wing region) in the bar area constitute the main velocity peak, whereas the particles in the bar contribute to the high-velocity tail, generating the {h}3-\\overline{V} correlation. If we remove the wing particles, the LOSVDs of the particles in the outer part of the bar only exhibit a low-velocity tail, resulting in a negative {h}3-\\overline{V} correlation, whereas the core areas in the central region still show weakly positive correlations. We discuss implications for IFU observations on bars, and show that the variation of the {h}3-\\overline{V} correlation in the disk galaxy may be used as a kinematic indicator of the bar and the B/PS bulge.

Galaxy Zoo: Observing secular evolution through bars

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheung, Edmond; Faber, S. M.; Koo, David C.

In this paper, we use the Galaxy Zoo 2 data set to study the behavior of bars in disk galaxies as a function of specific star formation rate (SSFR) and bulge prominence. Our sample consists of 13,295 disk galaxies, with an overall (strong) bar fraction of 23.6% ± 0.4%, of which 1154 barred galaxies also have bar length (BL) measurements. These samples are the largest ever used to study the role of bars in galaxy evolution. We find that the likelihood of a galaxy hosting a bar is anticorrelated with SSFR, regardless of stellar mass or bulge prominence. We findmore » that the trends of bar likelihood and BL with bulge prominence are bimodal with SSFR. We interpret these observations using state-of-the-art simulations of bar evolution that include live halos and the effects of gas and star formation. We suggest our observed trends of bar likelihood with SSFR are driven by the gas fraction of the disks, a factor demonstrated to significantly retard both bar formation and evolution in models. We interpret the bimodal relationship between bulge prominence and bar properties as being due to the complicated effects of classical bulges and central mass concentrations on bar evolution and also to the growth of disky pseudobulges by bar evolution. These results represent empirical evidence for secular evolution driven by bars in disk galaxies. This work suggests that bars are not stagnant structures within disk galaxies but are a critical evolutionary driver of their host galaxies in the local universe (z < 1).« less

Cysteine Substitution of Transmembrane Domain Amino Acids Alters the Ethanol Inhibition of GluN1/GluN2A N-Methyl-d-Aspartate Receptors

PubMed Central

Xu, Minfu; Smothers, C. Thetford

2015-01-01

N-Methyl-d-aspartate receptors (NMDARs) are inhibited by behaviorally relevant concentrations of ethanol, and residues within transmembrane (TM) domains of NMDARs, including TM3 GluN1 phenylalanine 639 (F639), regulate this sensitivity. In the present study, we used cysteine (C) mutagenesis to determine whether there are additional residues within nearby TM domains that regulate ethanol inhibition on NMDARs. GluN1(F639C)/GluN2A receptors were less inhibited by ethanol than wild-type receptors, and inhibition was restored to wild-type levels following treatment with ethanol-like methanethiosulfonate reagents. Molecular modeling identified six residues in the GluN1 TM1 domain (valine V566; serine S569) and the GluN2A TM4 domain (methionine, M817; V820, F821, and leucine, L824) that were in close vicinity to the TM3 F639 residue, and these were individually mutated to cysteine and tested for ethanol inhibition and receptor function. The F639C-induced decrease in ethanol inhibition was blunted by coexpression of GluN1 TM1 mutants V566C and S569C, and statistically significant interactions were observed for ethanol inhibition among V566C, F639C, and GluN2A TM4 mutants V820C and F821C and S569C, F639C, and GluN2A TM4 mutants F821C and L824C. Ethanol inhibition was also reduced when either GluN1 TM1 mutant V566C or S569C was combined with GluN2A V820C, suggesting a novel TM1:TM4 intrasubunit site of action for ethanol. Cysteines substituted at TM3 and TM4 sites previously suggested to interact with ethanol had less dramatic effects on ethanol inhibition. Overall, the results from these studies suggest that interactions among TM1, TM3, and TM4 amino acids in NMDARs are important determinants of ethanol action at these receptors. PMID:25635140

Single-Domain Antibodies Targeting Neuraminidase Protect against an H5N1 Influenza Virus Challenge

PubMed Central

Cardoso, Francisco Miguel; Ibañez, Lorena Itatí; Van den Hoecke, Silvie; De Baets, Sarah; Smet, Anouk; Roose, Kenny; Schepens, Bert; Descamps, Francis J.; Fiers, Walter; Muyldermans, Serge

2014-01-01

ABSTRACT Influenza virus neuraminidase (NA) is an interesting target of small-molecule antiviral drugs. We isolated a set of H5N1 NA-specific single-domain antibodies (N1-VHHm) and evaluated their in vitro and in vivo antiviral potential. Two of them inhibited the NA activity and in vitro replication of clade 1 and 2 H5N1 viruses. We then generated bivalent derivatives of N1-VHHm by two methods. First, we made N1-VHHb by genetically joining two N1-VHHm moieties with a flexible linker. Second, bivalent N1-VHH-Fc proteins were obtained by genetic fusion of the N1-VHHm moiety with the crystallizable region of mouse IgG2a (Fc). The in vitro antiviral potency against H5N1 of both bivalent N1-VHHb formats was 30- to 240-fold higher than that of their monovalent counterparts, with 50% inhibitory concentrations in the low nanomolar range. Moreover, single-dose prophylactic treatment with bivalent N1-VHHb or N1-VHH-Fc protected BALB/c mice against a lethal challenge with H5N1 virus, including an oseltamivir-resistant H5N1 variant. Surprisingly, an N1-VHH-Fc fusion without in vitro NA-inhibitory or antiviral activity also protected mice against an H5N1 challenge. Virus escape selection experiments indicated that one amino acid residue close to the catalytic site is required for N1-VHHm binding. We conclude that single-domain antibodies directed against influenza virus NA protect against H5N1 virus infection, and when engineered with a conventional Fc domain, they can do so in the absence of detectable NA-inhibitory activity. IMPORTANCE Highly pathogenic H5N1 viruses are a zoonotic threat. Outbreaks of avian influenza caused by these viruses occur in many parts of the world and are associated with tremendous economic loss, and these viruses can cause very severe disease in humans. In such cases, small-molecule inhibitors of the viral NA are among the few treatment options for patients. However, treatment with such drugs often results in the emergence of resistant viruses

Photoelastic analysis of mandibular full-arch implant-supported fixed dentures made with different bar materials and manufacturing techniques.

PubMed

Zaparolli, Danilo; Peixoto, Raniel Fernandes; Pupim, Denise; Macedo, Ana Paula; Toniollo, Marcelo Bighetti; Mattos, Maria da Glória Chiarello de

2017-12-01

To compare the stress distribution of mandibular full dentures supported with implants according to the bar materials and manufacturing techniques using a qualitative photoelastic analysis. An acrylic master model simulating the mandibular arch was fabricated with four Morse taper implant analogs of 4.5×6mm. Four different bars were manufactured according to different material and techniques: fiber-reinforced resin (G1, Trinia, CAD/CAM), commercially pure titanium (G2, cpTi, CAD/CAM), cobalt‑chromium (G3, Co-Cr, CAD/CAM) and cobalt‑chromium (G4, Co-Cr, conventional cast). Standard clinical and laboratory procedures were used by an experienced dental technician to fabricate 4 mandibular implant-supported dentures. The photoelastic model was created based on the acrylic master model. A load simulation (150N) was performed in total occlusion against the antagonist. Dentures with fiber-reinforced resin bar (G1) exhibited better stress distribution. Dentures with machined Co-Cr bar (G3) exhibited the worst standard of stress distribution, with an overload on the distal part of the posteriors implants, followed by dentures with cast Co-Cr bar (G4) and machined cpTi bar (G2). The fiber-reinforced resin bar exhibited an adequate stress distribution and can serve as a viable alternative for oral rehabilitation with mandibular full dentures supported with implants. Moreover, the use of the G1 group offered advantages including reduced weight and less possible overload to the implants components, leading to the preservation of the support structure. Copyright © 2017 Elsevier B.V. All rights reserved.

Finite element analysis on preferable I-bar clasp shape.

PubMed

Sato, Y; Tsuga, K; Abe, Y; Asahara, S; Akagawa, Y

2001-05-01

An I-bar clasp is one of the most popular direct retainers for distal-extension removable partial dentures. However, no adequate information is available on preferable shape as determined by biomechanics. This study aimed (1) to investigate, by finite element analysis (FEA), the dimensions and stress of I-bar clasps having the same stiffness, and (2) to estimate a mechanically preferable clasp design. Three-dimensional FEA models of I-bar clasps were created with vertical and horizontal straight sections connected by a curved section characterized by six parameters: thickness of the clasp tip, width of the clasp tip, radius of the curvature, horizontal distance between the base and the vertical axis, vertical dimension between the tip and the horizontal axis, and taper (change of width per unit length along the axis). Stress was calculated with a concentrated load of 5 N applied 2 mm from the tip of the clasp in the buccal direction. A thinner and wider clasp having an taper of 0.020-0.023 and radius of curvature of 2.75-3.00 showed less stress. The results suggest that such a shape might be the preferable I-bar clasp shape as biomechanical viewpoint.

DD-bar production and their interactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu Yanrui; Oka, Makoto; Takizawa, Makoto

2011-05-23

We have explored the bound state problem and the scattering problem of the DD-bar pair in a meson exchange model. When considering their production in the e{sup +}e{sup -} process, we included the DD-bar rescattering effect. Although it is difficult to answer whether the S-wave DD-bar bound state exists or not from the binding energies and the phase shifts, one may get an upper limit of the binding energy from the production of the BB-bar, the bottom analog of DD-bar.

Nuss bar migrations: occurrence and classification.

PubMed

Binkovitz, Lauren E; Zendejas, Benjamin; Moir, Christopher R; Binkovitz, Larry A

2016-12-01

Pectus excavatum results from dorsal deviation of the sternum causing narrowing of the anterior-posterior diameter of the chest. It can result in significant cosmetic deformities and cardiopulmonary compromise if severe. The Nuss procedure is a minimally invasive technique that involves placing a thin horizontally oriented metal bar below the dorsal sternal apex for correction of the pectus deformity. To identify the frequency and types of Nuss bar migrations, to present a new categorization of bar migrations, and to present examples of true migrations and pseudomigrations. We retrospectively reviewed the electronic medical records and all pertinent radiologic studies of 311 pediatric patients who underwent a Nuss procedure. We evaluated the frequency and type of bar migrations. Bar migration was demonstrated in 23 of 311 patients (7%) and occurred within a mean period of 26 days after surgery. Bar migrations were subjectively defined as deviation of the bar from the position demonstrated on the immediate postoperative radiographs and categorized as superior, inferior, rotation, lateral or flipped using a new classification system. Sixteen of the 23 migrations required re-operation. Nuss bar migration can be diagnosed with careful evaluation of serial radiographs. Nuss bar migration has a wide variety of appearances and requires exclusion of pseudomigration resulting from changes in patient positioning between radiologic examinations.

Structures of the N-acetyltransferase domain of Xylella fastidiosa N-acetyl-L-glutamate synthase/kinase with and without a His tag bound to N-acetyl-L-glutamate.

PubMed

Zhao, Gengxiang; Jin, Zhongmin; Allewell, Norma M; Tuchman, Mendel; Shi, Dashuang

2015-01-01

Structures of the catalytic N-acetyltransferase (NAT) domain of the bifunctional N-acetyl-L-glutamate synthase/kinase (NAGS/K) from Xylella fastidiosa bound to N-acetyl-L-glutamate (NAG) with and without an N-terminal His tag have been solved and refined at 1.7 and 1.4 Å resolution, respectively. The NAT domain with an N-terminal His tag crystallized in space group P4(1)2(1)2, with unit-cell parameters a=b=51.72, c=242.31 Å. Two subunits form a molecular dimer in the asymmetric unit, which contains ∼41% solvent. The NAT domain without an N-terminal His tag crystallized in space group P21, with unit-cell parameters a=63.48, b=122.34, c=75.88 Å, β=107.6°. Eight subunits, which form four molecular dimers, were identified in the asymmetric unit, which contains ∼38% solvent. The structures with and without the N-terminal His tag provide an opportunity to evaluate how the His tag affects structure and function. Furthermore, multiple subunits in different packing environments allow an assessment of the plasticity of the NAG binding site, which might be relevant to substrate binding and product release. The dimeric structure of the X. fastidiosa N-acetytransferase (xfNAT) domain is very similar to that of human N-acetyltransferase (hNAT), reinforcing the notion that mammalian NAGS is evolutionally derived from bifunctional bacterial NAGS/K.

Spectrally-resolved internal quantum efficiency and carrier dynamics of semipolar (10\\bar{1}1) core-shell triangular nanostripe GaN/InGaN LEDs

NASA Astrophysics Data System (ADS)

Okur, Serdal; Rishinaramangalam, Ashwin K.; Mishkat-Ul-Masabih, Saadat; Nami, Mohsen; Liu, Sheng; Brener, Igal; Brueck, Steven R. J.; Feezell, Daniel F.

2018-06-01

We investigate the spectrally resolved internal quantum efficiency (IQE) and carrier dynamics in semipolar (10\\bar{1}1) core–shell triangular nanostripe light-emitting diodes (TLEDs) using temperature-dependent photoluminescence (TDPL) and time-resolved photoluminescence (TRPL) at various excitation energy densities. Using electroluminescence, photoluminescence, and cathodoluminescence measurements, we verify the origins of the broad emission spectra from the nanostructures and confirm that localized regions of high-indium-content InGaN exist along the apex of the nanostructures. Spectrally resolved IQE measurements are then performed, with the spectra integrated from 400–450 nm and 450–500 nm to obtain the IQE of the QWs mainly near the sidewalls and apex of the TLEDs, respectively. TDPL and TRPL are used to decouple the radiative and non-radiative carrier lifetimes for different regions of the emission spectra. We observe that the IQE is higher for the spectral region between 450 nm and 500 nm compared to the IQE between 400 and 450 nm. This result is in contrast to the typical observation that the IQE of planar GaN-based LEDs is lower for longer wavelengths (i.e., higher indium contents). We also observe a longer non-radiative recombination lifetime for the longer wavelength portion of the spectrum. Several explanations are proposed for the improved IQE and longer non-radiative lifetime observed near the apex of the nanostructures. The results show that nanostructures may be leveraged to design more efficient green LEDs, potentially addressing a long-standing challenge in GaN-based materials.

The 4:1 Outer Lindblad Resonance of a long-slow bar as an explanation for the Hercules stream

NASA Astrophysics Data System (ADS)

Hunt, Jason A. S.; Bovy, Jo

2018-04-01

There are multiple groups of comoving stars in the Solar neighbourhood, which are possible signatures of one of the fundamental resonances of non-axisymmetric structure such as the Galactic bar or spiral arms. One such stream, Hercules, has been proposed to result from the outer Lindblad resonance (OLR) of a short fast rotating bar as shown analytically, or the corotation resonance (CR) of a longer slower rotating bar as observed in an N-body model. We show that by including an m = 4 Fourier component in an analytical long bar model, with an amplitude that is typical for bars in N-body simulations, we can reproduce a Hercules-like feature in the stellar kinematics of the Solar neighbourhood. We describe the expected symmetry in the velocity distribution arising from such a model, which we will soon be able to test with Gaia.

Integrated indicator to evaluate vehicle performance across: Safety, fuel efficiency and green domains.

PubMed

Torrao, G; Fontes, T; Coelho, M; Rouphail, N

2016-07-01

In general, car manufacturers face trade-offs between safety, efficiency and environmental performance when choosing between mass, length, engine power, and fuel efficiency. Moreover, the information available to the consumers makes difficult to assess all these components at once, especially when aiming to compare vehicles across different categories and/or to compare vehicles in the same category but across different model years. The main objective of this research was to develop an integrated tool able to assess vehicle's performance simultaneously for safety and environmental domains, leading to the research output of a Safety, Fuel Efficiency and Green Emissions (SEG) indicator able to evaluate and rank vehicle's performance across those three domains. For this purpose, crash data was gathered in Porto (Portugal) for the period 2006-2010 (N=1374). The crash database was analyzed and crash severity prediction models were developed using advanced logistic regression models. Following, the methodology for the SEG indicator was established combining the vehicle's safety and the environmental evaluation into an integrated analysis. The obtained results for the SEG indicator do not show any trade-off between vehicle's safety, fuel consumption and emissions. The best performance was achieved for newer gasoline passenger vehicles (<5year) with a smaller engine size (<1400cm(3)). According to the SEG indicator, a vehicle with these characteristics can be recommended for a safety-conscious profile user, as well as for a user more interested in fuel economy and/or in green performance. On the other hand, for larger engine size vehicles (>2000cm(3)) the combined score for safety user profile was in average more satisfactory than for vehicles in the smaller engine size group (<1400cm(3)), which suggests that in general, larger vehicles may offer extra protection. The achieved results demonstrate that the developed SEG integrated methodology can be a helpful tool for

N- vs. C-Domain Selectivity of Catalytic Inactivation of Human Angiotensin Converting Enzyme by Lisinopril-Coupled Transition Metal Chelates

PubMed Central

Hocharoen, Lalintip; Joyner, Jeff C.; Cowan, J. A.

2014-01-01

The N- and C-terminal domains of human somatic Angiotensin I Converting Enzyme (sACE-1) demonstrate distinct physiological functions, with resulting interest in the development of domain-selective inhibitors for specific therapeutic applications. Herein, the activity of lisinopril-coupled transition metal chelates were tested for both reversible binding and irreversible catalytic inactivation of sACE-1. C/N domain binding selectivity ratios ranged from 1 to 350, while rates of irreversible catalytic inactivation of the N- and C-domains were found to be significantly greater for the N-domain, suggesting a more optimal orientation of the M-chelate-lisinopril complexes within the active site of the N-domain of sACE-1. Finally, the combined effect of binding selectivity and inactivation selectivity was assessed for each catalyst (double-filter selectivity factors), and several catalysts were found to cause domain-selective catalytic inactivation. The results of this study demonstrate the ability to optimize the target selectivity of catalytic metallopeptides through both binding and orientation factors (double-filter effect). PMID:24228790

Stability diagrams for the surface patterns of GaN(0001bar) as a function of Schwoebel barrier height

NASA Astrophysics Data System (ADS)

Krzyżewski, Filip; Załuska-Kotur, Magdalena A.

2017-01-01

Height and type of Schwoebel barriers (direct or inverse) decides about the character of the surface instability. Different surface morphologies are presented. Step bunches, double steps, meanders, mounds and irregular patterns emerge at the surface as a result of step (Schwoebel) barriers at some temperature or miscut values. The study was carried out on the two-component kinetic Monte Carlo (kMC) model of GaN(0001bar) surface grown in nitrogen rich conditions. Diffusion of gallium adatoms over N-polar surface is slow and nitrogen adatoms are almost immobile. We show that in such conditions surfaces remain smooth when gallium adatoms diffuse in the presence of low inverse Schwoebel barrier. It is illustrated by adequate stability diagrams for surface morphologies.

Interaction between a Mg17Al12 precipitate and { 10\\bar 12} < 10\\bar 12 > twin boundary in magnesium alloys

NASA Astrophysics Data System (ADS)

Li, B.; Mathaudhu, S. N.

Interactions between Mg17Al12 precipitates and { 10\\bar 12} < 10\\bar 1\\bar 1 > twin boundaries (TBs) in magnesium were studied by molecular dynamics simulations. The results obtained agree well with experimental observations in which precipitates can be entirely engulfed by { 10\\bar 12} < 10\\bar 1\\bar 1 > twins without being sheared. Structural analysis of the TBs in the atomic scale shows that the TBs are extremely incoherent during twin growth and highly deviate from the { 10\\bar 12} twinning plane as previously observed in a number of experiments. The simulation studies indicate that { 10\\bar 12} < 10\\bar 1\\bar 1 > twinning was accomplished solely by atomic shuffling that converts the parent lattice to the twin lattice without involving twinning dislocations, resulting in zero shear strain at the TBs.

Predictions for the $$\\bar{B}^{0}\\rightarrow \\bar{K}^{\\ast 0}$$ X(YZ) and $$\\bar{B}^{0}_{s}\\rightarrow\\phi$$ X(YZ) with X(4160), Y(3940), Z(3930)

DOE PAGES

Liang, Wei -Hong; Molina, R.; Xie, Ju -Jun; ...

2015-05-22

We investigate the decay ofmore » $$\\bar B^0 \\to \\bar K^{*0} R$$ and $$\\bar B^0_s \\to \\phi R$$ with $R$ being the $X(4160)$, $Y(3940)$, $Z(3930)$ resonances. Under the assumption that these states are dynamically generated from the vector-vector interaction, as has been concluded from several theoretical studies, we use a reaction mechanism of quark production at the elementary level, followed by hadronization of one final $$q \\bar q$$ pair into two vectors and posterior final state interaction of this pair of vector mesons to produce the resonances. With this procedure we are able to predict five ratios for these decays, which are closely linked to the dynamical nature of these states, and also predict the order of magnitude of the branching ratios which we find of the order of $$10^{-4}$$, well within the present measurable range. In order to further test the dynamical nature of these resonances we study the $$\\bar B^0_s \\to \\phi D^* \\bar D^*$$ and $$\\bar B^0_s \\to \\phi D_s^* \\bar D_s^*$$ decays close to the $$D^* \\bar D^*$$ and $$D_s^* \\bar D_s^*$$ thresholds and make predictions for the ratio of the mass distributions in these decays and the $$\\bar B^0_s \\to \\phi R$$ decay widths. In conclusion, the measurement of these decays rates can help unravel the nature of these resonances.« less

Multiple-interactions among EMILIN1 and EMILIN2 N- and C-terminal domains.

PubMed

Bot, Simonetta; Andreuzzi, Eva; Capuano, Alessandra; Schiavinato, Alvise; Colombatti, Alfonso; Doliana, Roberto

2015-01-01

EMILIN1 and EMILIN2 belong to a family of extracellular matrix glycoproteins characterized by the N-terminal cysteine-rich EMI domain, a long segment with high probabilty for coiled-coil structure formation and a C-terminal gC1q domain. To study EMILIN1 and EMILIN2 interaction and assembly we have applied qualitative and quantitative two hybrid systems using constructs corresponding to the gC1q and EMI domains. The identified interactions were further confirmed in yeast extracts of co-transfected cells followed by co-immunoprecipitation. The data indicated that gC1q domains are able to self-interact as well as to interact one each other and with the EMI domains, but no self interactions were detected between the EMI domains. Furthermore EMILINs interactions were studied in 293-EBNA cells co-transfected with full lenght EMILIN1 and EMILIN2 constructs. Specific antibodies were able to co-immunoprecipitate EMILINs, indicating that also full-lenght proteins can give rise to non-covalent homo- and hetero-multimers even if reduced and alkylated before mixing. Immunofluorescence analysis on mouse cell cultures and tissues sections with specific antibodies showed co-distribution of EMILIN1 and EMILIN2. Thus, we can hypothesize that EMILINs multimers are formed by head-to-tail interaction between C-terminal and N-terminal domains of EMILIN1 and/or EMILIN2 but also by tail-to-tail interaction between gC1q domains. These multiple interactions may regulate homo-typic and/or hetero-typic linear and eventually lateral branching assemblies of EMILIN1 and EMILIN2 in tissues. Copyright © 2014. Published by Elsevier B.V.

A study of the effect of bulges on bar formation in disc galaxies

NASA Astrophysics Data System (ADS)

Kataria, Sandeep Kumar; Das, Mousumi

2018-04-01

We use N-body simulations of bar formation in isolated galaxies to study the effect of bulge mass and bulge concentration on bar formation. Bars are global disc instabilities that evolve by transferring angular momentum from the inner to outer discs and to the dark matter halo. It is well known that a massive spherical component such as halo in a disc galaxy can make it bar stable. In this study, we explore the effect of another spherical component, the bulge, on bar formation in disc galaxies. In our models, we vary both the bulge mass and concentration. We have used two sets of models: one that has a dense bulge and high surface density disc, and the other model has a less concentrated bulge and a lighter disc. In both models, we vary the bulge to disc mass fraction from 0 to 0.7. Simulations of both the models show that there is an upper cut-off in bulge-to-disc mass ratio Mb/Md above which bars cannot form; the cut-off is smaller for denser bulges (Mb/Md = 0.2) compared to less denser ones (Mb/Md = 0.5). We define a new criterion for bar formation in terms of the ratio of bulge to total radial force (Fb/Ftot) at the disc scale lengths above which bars cannot form. We find that if Fb/Ftot > 0.35, a disc is stable and a bar cannot form. Our results indicate that early-type disc galaxies can still form strong bars in spite of having massive bulges.

Too Much Bar and Not Enough Mitzvah? A Proposed Research Agenda on Bar/Bat Mitzvah

ERIC Educational Resources Information Center

Schoenfeld, Stuart

2010-01-01

Jewish educators are understandably interested in research on how bar/bat mitzvah affect Jewish education or research on what Jewish schools have done to avoid the distortions of a focus on bar/bat mitzvah. Research might also focus on the somewhat different and more ambitious topic of the role that bar/bat mitzvah play in contemporary Jewish…

Lung Middle Lobe Laceration Needing Lobectomy as Complication of Nuss Bar Removal.

PubMed

Henry, Brice; Lacroix, Valérie; Pirotte, Thierry; Docquier, Pierre-Louis

2018-01-01

Minimally invasive procedure for the treatment of pectus excavatum as described by Nuss has been used from 1987. The bar initially introduced blindly is now introduced under thoracoscopic control to increase safety of the procedure. It is usually removed two to three years after its insertion in a one-day procedure. Complications of the bar removal are rare but potentially serious. We report the case of a serious complication which occurred immediately after the Nuss bar removal. A 15-year-old boy underwent a Nuss procedure for a severe pectus excavatum without relevant complication. The bar has been removed two years after its insertion in a minimally invasive procedure. Unfortunately, he developed in the immediate postoperative period a hemopneumothorax due to a right middle lobe laceration which required a middle lobectomy by thoracotomy for hemostasis. Lesions of intrathoracic organs are a rare but potentially serious complication of the removal of the Nuss bar. We now propose to perform this procedure under thoracoscopic control to avoid it. In our experience, adhesions between the bar and the pleura are always present, and those with potential risk for bleeding or inducing intrathoracic organ lesions are suppressed prior to the bar removal.

Ribonucleocapsid Formation of SARS-COV Through Molecular Action of the N-Terminal Domain of N Protein

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saikatendu, K.S.; Joseph, J.S.; Subramanian, V.

Conserved amongst all coronaviruses are four structural proteins, the matrix (M), small envelope (E) and spike (S) that are embedded in the viral membrane and the nucleocapsid phosphoprotein (N), which exists in a ribonucleoprotein complex in their lumen. The N terminal domain of coronaviral N proteins (N-NTD) provides a scaffold for RNA binding while the C-terminal domain (N-CTD) mainly acts as oligomerization modules during assembly. The C-terminus of N protein anchors it to the viral membrane by associating with M protein. We characterized the structures of N-NTD from severe acute respiratory syndrome coronavirus (SARS-CoV) in two crystal forms, at 1.17Amore » (monoclinic) and 1.85 A (cubic) respectively, solved by molecular replacement using the homologous avian infectious bronchitis virus (IBV) structure. Flexible loops in the solution structure of SARS-CoV N-NTD are now shown to be well ordered around the beta-sheet core. The functionally important positively charged beta-hairpin protrudes out of the core and is oriented similar to that in the IBV N-NTD and is involved in crystal packing in the monoclinic form. In the cubic form, the monomers form trimeric units that stack in a helical array. Comparison of crystal packing of SARS-CoV and IBV N-NTDs suggest a common mode of RNA recognition, but probably associate differently in vivo during the formation of the ribonucleoprotein complex. Electrostatic potential distribution on the surface of homology models of related coronaviral N-NTDs hints that they employ different modes of both RNA recognition as well as oligomeric assembly, perhaps explaining why their nucleocapsids have different morphologies.« less

Using Common Spatial Distributions of Atoms to Relate Functionally Divergent Influenza Virus N10 and N11 Protein Structures to Functionally Characterized Neuraminidase Structures, Toxin Cell Entry Domains, and Non-Influenza Virus Cell Entry Domains

PubMed Central

Weininger, Arthur; Weininger, Susan

2015-01-01

The ability to identify the functional correlates of structural and sequence variation in proteins is a critical capability. We related structures of influenza A N10 and N11 proteins that have no established function to structures of proteins with known function by identifying spatially conserved atoms. We identified atoms with common distributed spatial occupancy in PDB structures of N10 protein, N11 protein, an influenza A neuraminidase, an influenza B neuraminidase, and a bacterial neuraminidase. By superposing these spatially conserved atoms, we aligned the structures and associated molecules. We report spatially and sequence invariant residues in the aligned structures. Spatially invariant residues in the N6 and influenza B neuraminidase active sites were found in previously unidentified spatially equivalent sites in the N10 and N11 proteins. We found the corresponding secondary and tertiary structures of the aligned proteins to be largely identical despite significant sequence divergence. We found structural precedent in known non-neuraminidase structures for residues exhibiting structural and sequence divergence in the aligned structures. In N10 protein, we identified staphylococcal enterotoxin I-like domains. In N11 protein, we identified hepatitis E E2S-like domains, SARS spike protein-like domains, and toxin components shared by alpha-bungarotoxin, staphylococcal enterotoxin I, anthrax lethal factor, clostridium botulinum neurotoxin, and clostridium tetanus toxin. The presence of active site components common to the N6, influenza B, and S. pneumoniae neuraminidases in the N10 and N11 proteins, combined with the absence of apparent neuraminidase function, suggests that the role of neuraminidases in H17N10 and H18N11 emerging influenza A viruses may have changed. The presentation of E2S-like, SARS spike protein-like, or toxin-like domains by the N10 and N11 proteins in these emerging viruses may indicate that H17N10 and H18N11 sialidase-facilitated cell

Effects of easy-to-use protein-rich energy bar on energy balance, physical activity and performance during 8 days of sustained physical exertion.

PubMed

Tanskanen, Minna M; Westerterp, Klaas R; Uusitalo, Arja L; Atalay, Mustafa; Häkkinen, Keijo; Kinnunen, Hannu O; Kyröläinen, Heikki

2012-01-01

Previous military studies have shown an energy deficit during a strenuous field training course (TC). This study aimed to determine the effects of energy bar supplementation on energy balance, physical activity (PA), physical performance and well-being and to evaluate ad libitum fluid intake during wintertime 8-day strenuous TC. Twenty-six men (age 20±1 yr.) were randomly divided into two groups: The control group (n = 12) had traditional field rations and the experimental (Ebar) group (n = 14) field rations plus energy bars of 4.1 MJ•day(-1). Energy (EI) and water intake was recorded. Fat-free mass and water loss were measured with deuterium dilution and elimination, respectively. The energy expenditure was calculated using the intake/balance method and energy availability as (EI/estimated basal metabolic rate). PA was monitored using an accelerometer. Physical performance was measured and questionnaires of upper respiratory tract infections (URTI), hunger and mood state were recorded before, during and after TC. Ebar had a higher EI and energy availability than the controls. However, decreases in body mass and fat mass were similar in both groups representing an energy deficit. No differences were observed between the groups in PA, water balance, URTI symptoms and changes in physical performance and fat-free mass. Ebar felt less hunger after TC than the controls and they had improved positive mood state during the latter part of TC while controls did not. Water deficit associated to higher PA. Furthermore, URTI symptoms and negative mood state associated negatively with energy availability and PA. An easy-to-use protein-rich energy bars did not prevent energy deficit nor influence PA during an 8-day TC. The high content of protein in the bars might have induced satiation decreasing energy intake from field rations. PA and energy intake seems to be primarily affected by other factors than energy supplementation such as mood state.

Effects of Easy-to-Use Protein-Rich Energy Bar on Energy Balance, Physical Activity and Performance during 8 Days of Sustained Physical Exertion

PubMed Central

Tanskanen, Minna M.; Westerterp, Klaas R.; Uusitalo, Arja L.; Atalay, Mustafa; Häkkinen, Keijo; Kinnunen, Hannu O.; Kyröläinen, Heikki

2012-01-01

Background Previous military studies have shown an energy deficit during a strenuous field training course (TC). This study aimed to determine the effects of energy bar supplementation on energy balance, physical activity (PA), physical performance and well-being and to evaluate ad libitum fluid intake during wintertime 8-day strenuous TC. Methods Twenty-six men (age 20±1 yr.) were randomly divided into two groups: The control group (n = 12) had traditional field rations and the experimental (Ebar) group (n = 14) field rations plus energy bars of 4.1 MJ•day−1. Energy (EI) and water intake was recorded. Fat-free mass and water loss were measured with deuterium dilution and elimination, respectively. The energy expenditure was calculated using the intake/balance method and energy availability as (EI/estimated basal metabolic rate). PA was monitored using an accelerometer. Physical performance was measured and questionnaires of upper respiratory tract infections (URTI), hunger and mood state were recorded before, during and after TC. Results Ebar had a higher EI and energy availability than the controls. However, decreases in body mass and fat mass were similar in both groups representing an energy deficit. No differences were observed between the groups in PA, water balance, URTI symptoms and changes in physical performance and fat-free mass. Ebar felt less hunger after TC than the controls and they had improved positive mood state during the latter part of TC while controls did not. Water deficit associated to higher PA. Furthermore, URTI symptoms and negative mood state associated negatively with energy availability and PA. Conclusion An easy-to-use protein-rich energy bars did not prevent energy deficit nor influence PA during an 8-day TC. The high content of protein in the bars might have induced satiation decreasing energy intake from field rations. PA and energy intake seems to be primarily affected by other factors than energy supplementation such

Domain identification moderates the effect of positive stereotypes on Chinese American women's math performance.

PubMed

Saad, Carmel S; Meyer, Oanh L; Dhindsa, Manveen; Zane, Nolan

2015-01-01

We examined whether an individual difference factor, math domain identification, moderated performance following positive stereotype activation. We hypothesized that positive stereotype activation would improve performance for those more math identified (compared to a control condition), but would hinder performance for those less math identified. We examined 116 Chinese American women (mean age = 19 years). Participants were assigned to the positive stereotype activation condition or to the control condition before completing a math test. Positive stereotype activation led more math identified participants to perform significantly better than the control condition, whereas it led less math identified participants to perform significantly worse than the control condition. Domain identification moderates the effect of positive stereotype activation. Educators should consider how testing situations are constructed, especially when test takers do not identify highly with the domain. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

Laboratory Study on Macro-Features of Wave Breaking Over Bars and Artificial Reefs

DTIC Science & Technology

1990-07-01

Prototype and Model Conditions of Case CE400 ( Pilot Test ) . 72 7 List of Design Parameters for Base Tests ... ........... . 72 8 List of Design Parameters...bar configurations, and the procedure was repeated. Pilot test 112. A pilot test was performed as a trial of the methodology and vali- dation of the...criterion on bar depth given by Larson and Kraus (1989) prior to actual testing . In this pilot test , the wave conditions and equilibrium bar formed in a

The ClpS-like N-domain is essential for the functioning of Ubr11, an N-recognin in Schizosaccharomyces pombe.

PubMed

Kitamura, Kenji

2014-01-01

Several Ubr ubiquitin ligases recognize the N-terminal amino acid of substrate proteins and promote their degradation via the Arg/N-end rule pathway. The primary destabilizing N-terminal amino acids in yeast are classified into type 1 (Arg, Lys, and His) and type 2 (Phe, Trp, Tyr, Leu, Ile, and Met-Ф) residues. The type 1 and type 2 residues bind to the UBR box and the ClpS/N-domain, respectively, in canonical Ubr ubiquitin ligases that act as N-recognins. In this study, the requirement for type 1 and type 2 amino acid recognition by Schizosaccharomyces pombe Ubr11 was examined in vivo. Consistent with the results of previous studies, the ubr11∆ null mutant was found to be defective in oligopeptide uptake and resistant to ergosterol synthesis inhibitors. Furthermore, the ubr11∆ mutant was also less sensitive to some protein synthesis inhibitors. A ubr11 ClpS/N-domain mutant, which retained ubiquitin ligase activity but could not recognize type 2 amino acids, phenocopied all known defects of the ubr11∆ mutant. However, the recognition of type 1 residues by Ubr11 was not required for its functioning, and no severe physiological abnormalities were observed in a ubr11 mutant defective in the recognition of type 1 residues. These results reinforce the fundamental importance of the ClpS/N-domain for the functioning of the N-recognin, Ubr11.

Miro's N-Terminal GTPase Domain Is Required for Transport of Mitochondria into Axons and Dendrites

PubMed Central

Babic, Milos; Russo, Gary J.; Wellington, Andrea J.; Sangston, Ryan M.; Gonzalez, Migdalia

2015-01-01

Mitochondria are dynamically transported in and out of neuronal processes to maintain neuronal excitability and synaptic function. In higher eukaryotes, the mitochondrial GTPase Miro binds Milton/TRAK adaptor proteins linking microtubule motors to mitochondria. Here we show that Drosophila Miro (dMiro), which has previously been shown to be required for kinesin-driven axonal transport, is also critically required for the dynein-driven distribution of mitochondria into dendrites. In addition, we used the loss-of-function mutations dMiroT25N and dMiroT460N to determine the significance of dMiro's N-terminal and C-terminal GTPase domains, respectively. Expression of dMiroT25N in the absence of endogenous dMiro caused premature lethality and arrested development at a pupal stage. dMiroT25N accumulated mitochondria in the soma of larval motor and sensory neurons, and prevented their kinesin-dependent and dynein-dependent distribution into axons and dendrites, respectively. dMiroT25N mutant mitochondria also were severely fragmented and exhibited reduced kinesin and dynein motility in axons. In contrast, dMiroT460N did not impair viability, mitochondrial size, or the distribution of mitochondria. However, dMiroT460N reduced dynein motility during retrograde mitochondrial transport in axons. Finally, we show that substitutions analogous to the constitutively active Ras-G12V mutation in dMiro's N-terminal and C-terminal GTPase domains cause neomorphic phenotypic effects that are likely unrelated to the normal function of each GTPase domain. Overall, our analysis indicates that dMiro's N-terminal GTPase domain is critically required for viability, mitochondrial size, and the distribution of mitochondria out of the neuronal soma regardless of the employed motor, likely by promoting the transition from a stationary to a motile state. PMID:25855186

Large velocity dispersion of molecular gas in bars of strongly barred galaxies NGC 1300 and NGC 5383

NASA Astrophysics Data System (ADS)

Maeda, Fumiya; Ohta, Kouji; Fujimoto, Yusuke; Habe, Asao; Baba, Junichi

2018-06-01

We carried out ^{12}CO(J = 1-0) observations toward bar and arm regions of the strongly barred galaxies NGC 1300 and NGC 5383 with the Nobeyama 45 m radio telescope (beam size of 1-2 kpc in the galaxies). The aim of the observations is to qualitatively examine a new scenario for the suppression of star formation in bars based on recent high-resolution numerical simulations: higher speed collisions between molecular clouds in the bar region compared with the arm region suppress the massive star formation. CO emissions were detected from all the regions, indicating the presence of molecular gases in the strong bars without associating clear H II regions. In both galaxies, the velocity width of the CO line profile tends to be larger in the bar region than in the arm region, which is qualitatively consistent with the new scenario.

TIME-DEPENDENT COROTATION RESONANCE IN BARRED GALAXIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Yu-Ting; Taam, Ronald E.; Pfenniger, Daniel, E-mail: ytwu@asiaa.sinica.edu.tw, E-mail: daniel.pfenniger@unige.ch, E-mail: taam@asiaa.sinica.edu.tw

2016-10-20

The effective potential neighboring the corotation resonance region in barred galaxies is shown to be strongly time-dependent in any rotating frame, due to the competition of nearby perturbations of similar strengths with differing rotation speeds. Contrary to the generally adopted assumption that in the bar rotating frame the corotation region should possess four stationary equilibrium points (Lagrange points), with high quality N -body simulations, we localize the instantaneous equilibrium points (EPs) and find that they circulate or oscillate broadly in azimuth with respect to the pattern speeds of the inner or outer perturbations. This implies that at the particle levelmore » the Jacobi integral is not well conserved around the corotation radius. That is, angular momentum exchanges decouple from energy exchanges, enhancing the chaotic diffusion of stars through the corotation region.« less

From the chromatin interaction network to the organization of the human genome into replication N/U-domains

NASA Astrophysics Data System (ADS)

Boulos, Rasha E.; Julienne, Hanna; Baker, Antoine; Chen, Chun-Long; Petryk, Nataliya; Kahli, Malik; dʼAubenton-Carafa, Yves; Goldar, Arach; Jensen, Pablo; Hyrien, Olivier; Thermes, Claude; Arneodo, Alain; Audit, Benjamin

2014-11-01

The three-dimensional (3D) architecture of the mammalian nucleus is now being unraveled thanks to the recent development of chromatin conformation capture (3C) technologies. Here we report the results of a combined multiscale analysis of genome-wide mean replication timing and chromatin conformation data that reveal some intimate relationships between chromatin folding and human DNA replication. We previously described megabase replication N/U-domains as mammalian multiorigin replication units, and showed that their borders are ‘master’ replication initiation zones that likely initiate cascades of origin firing responsible for the stereotypic replication of these domains. Here, we demonstrate that replication N/U-domains correspond to the structural domains of self-interacting chromatin, and that their borders act as insulating regions both in high-throughput 3C (Hi-C) data and high-resolution 3C (4C) experiments. Further analyses of Hi-C data using a graph-theoretical approach reveal that N/U-domain borders are long-distance, interconnected hubs of the chromatin interaction network. Overall, these results and the observation that a well-defined ordering of chromatin states exists from N/U-domain borders to centers suggest that ‘master’ replication initiation zones are at the heart of a high-order, epigenetically controlled 3D organization of the human genome.

A UNIFIED FRAMEWORK FOR THE ORBITAL STRUCTURE OF BARS AND TRIAXIAL ELLIPSOIDS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Valluri, Monica; Abbott, Caleb; Shen, Juntai

We examine a large random sample of orbits in two self-consistent simulations of N-body bars. Orbits in these bars are classified both visually and with a new automated orbit classification method based on frequency analysis. The well-known prograde x1 orbit family originates from the same parent orbit as the box orbits in stationary and rotating triaxial ellipsoids. However, only a small fraction of bar orbits (∼4%) have predominately prograde motion like their periodic parent orbit. Most bar orbits arising from the x1 orbit have little net angular momentum in the bar frame, making them equivalent to box orbits in rotatingmore » triaxial potentials. In these simulations a small fraction of bar orbits (∼7%) are long-axis tubes that behave exactly like those in triaxial ellipsoids: they are tipped about the intermediate axis owing to the Coriolis force, with the sense of tipping determined by the sign of their angular momentum about the long axis. No orbits parented by prograde periodic x2 orbits are found in the pure bar model, but a tiny population (∼2%) of short-axis tube orbits parented by retrograde x4 orbits are found. When a central point mass representing a supermassive black hole (SMBH) is grown adiabatically at the center of the bar, those orbits that lie in the immediate vicinity of the SMBH are transformed into precessing Keplerian orbits that belong to the same major families (short-axis tubes, long-axis tubes and boxes) occupying the bar at larger radii. During the growth of an SMBH, the inflow of mass and outward transport of angular momentum transform some x1 and long-axis tube orbits into prograde short-axis tubes. This study has important implications for future attempts to constrain the masses of SMBHs in barred galaxies using orbit-based methods like the Schwarzschild orbit superposition scheme and for understanding the observed features in barred galaxies.« less

Distributed Long-Gauge Optical Fiber Sensors Based Self-Sensing FRP Bar for Concrete Structure

PubMed Central

Tang, Yongsheng; Wu, Zhishen

2016-01-01

Brillouin scattering-based distributed optical fiber (OF) sensing technique presents advantages for concrete structure monitoring. However, the existence of spatial resolution greatly decreases strain measurement accuracy especially around cracks. Meanwhile, the brittle feature of OF also hinders its further application. In this paper, the distributed OF sensor was firstly proposed as long-gauge sensor to improve strain measurement accuracy. Then, a new type of self-sensing fiber reinforced polymer (FRP) bar was developed by embedding the packaged long-gauge OF sensors into FRP bar, followed by experimental studies on strain sensing, temperature sensing and basic mechanical properties. The results confirmed the superior strain sensing properties, namely satisfied accuracy, repeatability and linearity, as well as excellent mechanical performance. At the same time, the temperature sensing property was not influenced by the long-gauge package, making temperature compensation easy. Furthermore, the bonding performance between self-sensing FRP bar and concrete was investigated to study its influence on the sensing. Lastly, the sensing performance was further verified with static experiments of concrete beam reinforced with the proposed self-sensing FRP bar. Therefore, the self-sensing FRP bar has potential applications for long-term structural health monitoring (SHM) as embedded sensors as well as reinforcing materials for concrete structures. PMID:26927110

Distributed Long-Gauge Optical Fiber Sensors Based Self-Sensing FRP Bar for Concrete Structure.

PubMed

Tang, Yongsheng; Wu, Zhishen

2016-02-25

Brillouin scattering-based distributed optical fiber (OF) sensing technique presents advantages for concrete structure monitoring. However, the existence of spatial resolution greatly decreases strain measurement accuracy especially around cracks. Meanwhile, the brittle feature of OF also hinders its further application. In this paper, the distributed OF sensor was firstly proposed as long-gauge sensor to improve strain measurement accuracy. Then, a new type of self-sensing fiber reinforced polymer (FRP) bar was developed by embedding the packaged long-gauge OF sensors into FRP bar, followed by experimental studies on strain sensing, temperature sensing and basic mechanical properties. The results confirmed the superior strain sensing properties, namely satisfied accuracy, repeatability and linearity, as well as excellent mechanical performance. At the same time, the temperature sensing property was not influenced by the long-gauge package, making temperature compensation easy. Furthermore, the bonding performance between self-sensing FRP bar and concrete was investigated to study its influence on the sensing. Lastly, the sensing performance was further verified with static experiments of concrete beam reinforced with the proposed self-sensing FRP bar. Therefore, the self-sensing FRP bar has potential applications for long-term structural health monitoring (SHM) as embedded sensors as well as reinforcing materials for concrete structures.

Age differences between the controlled force exertion measured by a computer-generated sinusoidal and a bar chart display.

PubMed

Nagasawa, Yoshinori; Demura, Shinichi; Takahashi, Kenji

2013-01-01

It is important to develop an accurate method of measuring controlled force exertion. This study examined the age differences between the controlled force exertion measured by a sinusoidal waveform and a bar chart display. The participants comprised 175 right-handed male adults aged 20-86 years. The participants were divided into three age groups: young (n=53), middle-aged (n=71), and elderly (n=51). They matched the submaximal grip strength exerted by their dominant hand to changing demand values displayed as either a sinusoidal waveform or a bar chart appearing on a personal computer screen. The participants performed the controlled force exertion test three times with a 1-min inter-trial interval using their dominant hand. The dependent variable was the total sum of the percentage values of the differences between the demand value and grip exertion value for more than 25s. The coefficient of variance had almost the same range in all age groups in both displays (CVSW=28.0-36.9, CVBC=29.1-32.6), but the elderly group showed a somewhat higher value with the sinusoidal waveform. Significant correlations were found between the scores with sinusoidal waveform and bar chart displays in the young, middle-aged, and elderly groups (r=0.47-0.68), but the correlations did not differ significantly between the age groups. Scores over 1500% in sinusoidal and bar chart display were found in one and two participants, respectively, in the middle-aged group and in 12% and 16% of the participants, respectively, in the elderly group. Furthermore, among all participants, only 8% of participants in the elderly group scored over 1500% in both displays. Scores over 1500% in both displays are considered to be considerably worse in controlled force exertion than lower scores. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Bar Coding and Tracking in Pathology.

PubMed

Hanna, Matthew G; Pantanowitz, Liron

2016-03-01

Bar coding and specimen tracking are intricately linked to pathology workflow and efficiency. In the pathology laboratory, bar coding facilitates many laboratory practices, including specimen tracking, automation, and quality management. Data obtained from bar coding can be used to identify, locate, standardize, and audit specimens to achieve maximal laboratory efficiency and patient safety. Variables that need to be considered when implementing and maintaining a bar coding and tracking system include assets to be labeled, bar code symbologies, hardware, software, workflow, and laboratory and information technology infrastructure as well as interoperability with the laboratory information system. This article addresses these issues, primarily focusing on surgical pathology. Copyright © 2016 Elsevier Inc. All rights reserved.

Bar Coding and Tracking in Pathology.

PubMed

Hanna, Matthew G; Pantanowitz, Liron

2015-06-01

Bar coding and specimen tracking are intricately linked to pathology workflow and efficiency. In the pathology laboratory, bar coding facilitates many laboratory practices, including specimen tracking, automation, and quality management. Data obtained from bar coding can be used to identify, locate, standardize, and audit specimens to achieve maximal laboratory efficiency and patient safety. Variables that need to be considered when implementing and maintaining a bar coding and tracking system include assets to be labeled, bar code symbologies, hardware, software, workflow, and laboratory and information technology infrastructure as well as interoperability with the laboratory information system. This article addresses these issues, primarily focusing on surgical pathology. Copyright © 2015 Elsevier Inc. All rights reserved.

Why Are Some Galaxies Not Barred?

NASA Astrophysics Data System (ADS)

Saha, Kanak; Elmegreen, Bruce

2018-05-01

Although more than two-thirds of star-forming disk galaxies in the local universe are barred, some galaxies remain unbarred, occupying the upper half of the Hubble tuning fork diagram. Numerical simulations almost always produce bars spontaneously, so it remains a challenge to understand how galaxies sometimes prevent bars from forming. Using a set of collisionless simulations, we first reproduce the common result that cold stellar disks surrounding a classical bulge become strongly unstable to non-axisymmetric perturbations, leading to the rapid formation of spiral structure and bars. However, our analyses show that galaxy models with compact classical bulges (whose average density is greater than or comparable to the disk density calculated within bulge half-mass radii) are able to prevent bar formation for at least 4 Gyr even when the stellar disk is maximal and having low Toomre Q. Such bar prevention is the result of several factors such as (a) a small inner Lindblad resonance with a high angular rate, which contaminates an incipient bar with x 2 orbits, and (b) rapid loss of angular momentum accompanied by a rapid heating in the center from initially strong bar and spiral instabilities in a low-Q disk; in other words, a rapid initial rise to a value larger than ∼5 of the ratio of the random energy to the rotational energy in the central region of the galaxy.

Structure of the EMMPRIN N-terminal domain 1: Dimerization via [beta]-strand swapping

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luo, Jinquan; Teplyakov, Alexey; Obmolova, Galina

2010-09-27

Extracellular matrix metalloproteinase inducer (EMMPRIN), also known as Hab18G, CD147, Basigin, M6, and neurothelin, is a membrane glycoprotein expressed on the surface of various cell types and many cancer cells. EMMPRIN stimulates adjacent fibroblasts and tumor cells to produce matrix metalloproteinases and plays an important role in tumor invasion and metastasis, angiogenesis, spermatogensis and fertilization, cell-cell adhesion and communication, and other biological processes (reviewed in Ref. 1 and references therein). It was demonstrated that the EMMPRIN extracellular domain (ECD), which structurally belongs to the IgG superfamily, can form homo-oligomers in a cis dependent manner and the N-terminal domain 1 (residuesmore » 22-101) was necessary and sufficient to mediate this interaction. The crystal structure of the ECD of recombinant human EMMPRIN (Hab18G/CD147) expressed in E. coli was reported at 2.8 {angstrom} resolution (Yu et al. 2008). The construct consists of residues 22-205 of the mature protein and has both an N-terminal IgC2 domain (ND1, residues 22-101) and a C-terminal IgC2 domain (ND2, residues 107-205). The two domains are joined by a five amino acid residue linker that constitutes a flexible hinge between the two domains. The crystal form has four copies of the molecule in the asymmetric unit, each of which has a different inter-domain angle that varies from 121{sup o} to 144{sup o}. The two domains each have a conserved disulfide bridge and both are comprised of two {beta}-sheets formed by strands EBA and GFCC, and DEBA and AGFCC for ND1 and ND2, respectively. Based on the crystal packing in this structure, the authors proposed that lateral packing between the two IgG domains of EMMPRIN ECD represents a potential mechanism for cell adhesion. Here we report the 2.0-{angstrom} crystal structure of the N-terminal domain of EMMPRIN ECD (ND1) expressed in mammalian cells. The overall structure of the domain is very similar to that in the full

A unique GCN5-related glucosamine N-acetyltransferase region exist in the fungal multi-domain glycoside hydrolase family 3 β-N-acetylglucosaminidase.

PubMed

Qin, Zhen; Xiao, Yibei; Yang, Xinbin; Mesters, Jeroen R; Yang, Shaoqing; Jiang, Zhengqiang

2015-12-16

Glycoside hydrolase (GH) family 3 β-N-acetylglucosaminidases widely exist in the filamentous fungi, which may play a key role in chitin metabolism of fungi. A multi-domain GH family 3 β-N-acetylglucosaminidase from Rhizomucor miehei (RmNag), exhibiting a potential N-acetyltransferase region, has been recently reported to show great potential in industrial applications. In this study, the crystal structure of RmNag was determined at 2.80 Å resolution. The three-dimensional structure of RmNag showed four distinctive domains, which belong to two distinguishable functional regions--a GH family 3 β-N-acetylglucosaminidase region (N-terminal) and a N-acetyltransferase region (C-terminal). From structural and functional analysis, the C-terminal region of RmNag was identified as a unique tandem array linking general control non-derepressible 5 (GCN5)-related N-acetyltransferase (GNAT), which displayed glucosamine N-acetyltransferase activity. Structural analysis of this glucosamine N-acetyltransferase region revealed that a unique glucosamine binding pocket is located in the pantetheine arm binding terminal region of the conserved CoA binding pocket, which is different from all known GNAT members. This is the first structural report of a glucosamine N-acetyltransferase, which provides novel structural information about substrate specificity of GNATs. The structural and functional features of this multi-domain β-N-acetylglucosaminidase could be useful in studying the catalytic mechanism of GH family 3 proteins.

Simulating a slow bar in the low surface brightness galaxy UGC 628

NASA Astrophysics Data System (ADS)

Chequers, Matthew H.; Spekkens, Kristine; Widrow, Lawrence M.; Gilhuly, Colleen

2016-12-01

We present a disc-halo N-body model of the low surface brightness galaxy UGC 628, one of the few systems that harbours a `slow' bar with a ratio of corotation radius to bar length of R ≡ R_c/a_b ˜ 2. We select our initial conditions using SDSS DR10 photometry, a physically motivated radially variable mass-to-light ratio profile, and rotation curve data from the literature. A global bar instability grows in our submaximal disc model, and the disc morphology and dynamics agree broadly with the photometry and kinematics of UGC 628 at times between peak bar strength and the onset of buckling. Prior to bar formation, the disc and halo contribute roughly equally to the potential in the galaxy's inner region, giving the disc enough self-gravity for bar modes to grow. After bar formation, there is significant mass redistribution, creating a baryon-dominated inner and dark matter-dominated outer disc. This implies that, unlike most other low surface brightness galaxies, UGC 628 is not dark matter dominated everywhere. Our model nonetheless implies that UGC 628 falls on the same relationship between dark matter fraction and rotation velocity found for high surface brightness galaxies, and lends credence to the argument that the disc mass fraction measured at the location where its contribution to the potential peaks is not a reliable indicator of its dynamical importance at all radii.

Behavior intentions of the public after bans on smoking in restaurants and bars.

PubMed Central

Biener, L; Siegel, M

1997-01-01

OBJECTIVES: This study assessed the potential effect of smoke-free policies on bar and restaurant patronage. METHODS: Random-digit dialing techniques were used in surveying a representative sample of Massachusetts adults (n = 2356) by telephone. RESULTS: Approximately 61% of the respondents predicted no change in their use of restaurants in response to smoke-free policies, 30% predicted increased use, and 8% predicted decreased use. In turn, 69% of the respondents predicted no change in their patronage of bars, while 20% predicted increased use and 11% predicted decreased use. CONCLUSIONS: These results suggest that smoke-free policies are likely to increase overall patronage of bars and restaurants. PMID:9431301

Analytical potential-density pairs for bars

NASA Astrophysics Data System (ADS)

Vogt, D.; Letelier, P. S.

2010-11-01

An identity that relates multipolar solutions of the Einstein equations to Newtonian potentials of bars with linear densities proportional to Legendre polynomials is used to construct analytical potential-density pairs of infinitesimally thin bars with a given linear density profile. By means of a suitable transformation, softened bars that are free of singularities are also obtained. As an application we study the equilibrium points and stability for the motion of test particles in the gravitational field for three models of rotating bars.

Testing of a Spray-bar Thermodynamic Vent System in Liquid Nitrogen

NASA Technical Reports Server (NTRS)

Flachbart, R. H.; Hastings, L. J.; Hedayat, A.; Nelson, S. L.; Tucker, S. P.

2005-01-01

To support development of a microgravity pressure control capability for liquid oxygen, thermodynamic vent system (TVS) testing was conducted at Marshall Space Flight Center (MSFC) using liquid nitrogen (LN2) as a LOX simulant. The spray bar TVS hardware used was originally designed by the Boeing Company for testing in liquid hydrogen (LH2). With this concept, a small portion of the tank fluid is passed through a Joule-Thomson (J-T) device, and then through a longitudinal spray bar mixed-heat exchanger in order to cool the bulk fluid. To accommodate the larger mass flow rates associated with LN2, the TVS hardware was modified by replacing the recirculation pump with an LN2 compatible pump and replacing the J-T valve. The primary advantage of the spray-bar configuration is that tank pressure control can be achieved independent of liquid and vapor location, enhancing the applicability of ground test data to microgravity conditions. Performance testing revealed that the spray-bar TVS was effective in controlling tank pressure within a 6.89 kPa band for fill levels of 90%, 50%, and 25%. Tests were also conducted with gaseous helium (GHe) in the ullage. The TVS operated nominally with GHe in the ullage, with performance similar to the tests with gaseous nitrogen (GN2). Testing demonstrated that the spray-bar TVS design was flexible enough for use in two different propellants with minimal hardware modifications.

The role of chest radiography following pectus bar removal.

PubMed

Farach, Sandra M; Danielson, Paul D; Chandler, Nicole M

2016-07-01

Surgical correction of pectus excavatum (PE) via a minimally invasive approach involves placement of a steel bar, which is subsequently removed. The purpose of our study was to evaluate the incidence of pneumothorax and the role for chest radiography (CXR) in patients undergoing pectus bar removal. A retrospective review of 84 patients who underwent pectus bar removal from 2006 to 2014 was performed. Results of postoperative CXR, repeat imaging, need for chest thoracostomy tube placement, and complications were analyzed. Mean Haller index prior to correction was 4.3 ± 0.9. The mean time between PE repair and bar removal was 2.3 ± 0.6 years. Sixty-one patients (72.6 %) had a postoperative CXR. Thirty-one (50.8 %) had no acute findings, 20 (32.8 %) had findings of atelectasis or subcutaneous emphysema, and 10 (16.4 %) had a pneumothorax. One patient (1.6 %) had a second postoperative CXR for a small pneumothorax and rib fractures. There were two complications (2.4 %). No chest tubes were placed for pneumothorax, and 95 % of patients were discharged the day of surgery. Postoperative CXR following pectus bar removal is unnecessary given the low incidence of postoperative pneumothorax requiring intervention. Patients can be safely discharged the day of surgery without the need for routine postoperative chest imaging.

Preparation of a Breadfruit Flour Bar.

PubMed

Nochera, Carmen L; Ragone, Diane

2016-05-20

Breadfruit is a nutritious, high energy food with a low quantity of protein but excellent protein quality. It has the potential to be developed into desired products which will help increase its utilization and add value to the crop. The overall purposes of this investigation were to develop a portable, nutritious, ready-to-eat breadfruit product (bar), test the sensory qualities of the product, and evaluate the nutritional properties of the product. Flour made from the Micronesian variety, Meinpadahk ( Artocarpus altilis × Artocarpus mariannensis ), was utilized for the development of the breadfruit bar. Breadfruit is a rich source of fiber, vitamins such as vitamin C, minerals such as potassium, and phytochemicals such as flavonoids. Nutritional labeling indicates that the breadfruit bar is high in carbohydrates and low in fat, and sensory evaluation indicates that 81% of the panelists found the bar acceptable while 19% disliked the bar. The breadfruit bar can provide an appealing and inexpensive gluten-free food source based on locally available breadfruit.

Static and dynamic behaviour of nonlocal elastic bar using integral strain-based and peridynamic models

NASA Astrophysics Data System (ADS)

Challamel, Noël

2018-04-01

The static and dynamic behaviour of a nonlocal bar of finite length is studied in this paper. The nonlocal integral models considered in this paper are strain-based and relative displacement-based nonlocal models; the latter one is also labelled as a peridynamic model. For infinite media, and for sufficiently smooth displacement fields, both integral nonlocal models can be equivalent, assuming some kernel correspondence rules. For infinite media (or finite media with extended reflection rules), it is also shown that Eringen's differential model can be reformulated into a consistent strain-based integral nonlocal model with exponential kernel, or into a relative displacement-based integral nonlocal model with a modified exponential kernel. A finite bar in uniform tension is considered as a paradigmatic static case. The strain-based nonlocal behaviour of this bar in tension is analyzed for different kernels available in the literature. It is shown that the kernel has to fulfil some normalization and end compatibility conditions in order to preserve the uniform strain field associated with this homogeneous stress state. Such a kernel can be built by combining a local and a nonlocal strain measure with compatible boundary conditions, or by extending the domain outside its finite size while preserving some kinematic compatibility conditions. The same results are shown for the nonlocal peridynamic bar where a homogeneous strain field is also analytically obtained in the elastic bar for consistent compatible kinematic boundary conditions at the vicinity of the end conditions. The results are extended to the vibration of a fixed-fixed finite bar where the natural frequencies are calculated for both the strain-based and the peridynamic models.

N-Terminal Domain of Turkey Pancreatic Lipase is Active on Long Chain Triacylglycerols and Stabilized by Colipase

PubMed Central

Bou Ali, Madiha; Karray, Aida; Gargouri, Youssef; Ben Ali, Yassine

2013-01-01

The gene encoding the TPL N-terminal domain (N-TPL), fused with a His6-tag, was cloned and expressed in Pichia pastoris, under the control of the glyceraldehyde-3-phosphate dehydrogenase (GAP) constitutive promoter. The recombinant protein was successfully expressed and secreted with an expression level of 5 mg/l of culture medium after 2 days of culture. The N-TPL was purified through a one-step Ni-NTA affinity column with a purification factor of approximately 23-fold. The purified N-TPL, with a molecular mass of 35 kDa, had a specific activity of 70 U/mg on tributyrin. Surprisingly, this domain was able to hydrolyse long chain TG with a specific activity of 11 U/mg using olive oil as substrate. This result was confirmed by TLC analysis showing that the N-TPL was able to hydrolyse insoluble substrates as olive oil. N-TPL was unstable at temperatures over 37°C and lost 70% of its activity at acid pH, after 5 min of incubation. The N-TPL exhibited non linear kinetics, indicating its rapid denaturation at the tributyrin–water interface. Colipase increased the N-TPL stability at the lipid-water interface, so the TPL N-terminal domain probably formed functional interactions with colipase despite the absence of the C-terminal domain. PMID:23977086

49 CFR 236.705 - Bar, locking.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Bar, locking. 236.705 Section 236.705..., MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.705 Bar, locking. A bar in an interlocking machine to which the locking dogs are attached. ...

Minimally Invasive Repair of Pectus Excavatum Without Bar Stabilizers Using Endo Close.

PubMed

Pio, Luca; Carlucci, Marcello; Leonelli, Lorenzo; Erminio, Giovanni; Mattioli, Girolamo; Torre, Michele

2016-02-01

Since the introduction of the Nuss technique for pectus excavatum (PE) repair, stabilization of the bar has been a matter of debate and a crucial point for the outcome, as bar dislocation remains one of the most frequent complications. Several techniques have been described, most of them including the use of a metal stabilizer, which, however, can increase morbidity and be difficult to remove. Our study compares bar stabilization techniques in two groups of patients, respectively, with and without the metal stabilizer. A retrospective study on patients affected by PE and treated by the Nuss technique from January 2012 to June 2013 at our institution was performed in order to evaluate the efficacy of metal stabilizers. Group 1 included patients who did not have the metal stabilizer inserted; stabilization was achieved with multiple (at least four) bilateral pericostal Endo Close™ (Auto Suture, US Surgical; Tyco Healthcare Group, Norwalk, CT) sutures. Group 2 included patients who had a metal stabilizer placed because pericostal sutures could not be used bilaterally. We compared the two groups in terms of bar dislocation rate, surgical operative time, and other complications. Statistical analysis was performed with the Mann-Whitney U test and Fisher's exact test. Fifty-seven patients were included in the study: 37 in Group 1 and 20 in Group 2. Two patients from Group 2 had a bar dislocation. Statistical analysis showed no difference between the two groups in dislocation rate or other complications. In our experience, the placement of a metal stabilizer did not reduce the rate of bar dislocation. Bar stabilization by the pericostal Endo Close suture technique appears to have no increase in morbidity or migration compared with the metal lateral stabilizer technique.

Role of Plant-Specific N-Terminal Domain of Maize CK2β1 Subunit in CK2β Functions and Holoenzyme Regulation

PubMed Central

Vélez-Bermúdez, Isabel C.; Carretero-Paulet, Lorenzo; Lumbreras, Victoria; Pagès, Montserrat

2011-01-01

Protein kinase CK2 is a highly pleiotropic Ser/Thr kinase ubiquituous in eukaryotic organisms. CK2 is organized as a heterotetrameric enzyme composed of two types of subunits: the catalytic (CK2α) and the regulatory (CK2β). The CK2β subunits enhance the stability, activity and specificity of the holoenzyme, but they can also perform functions independently of the CK2 tetramer. CK2β regulatory subunits in plants differ from their animal or yeast counterparts, since they present an additional specific N-terminal extension of about 90 aminoacids that shares no homology with any previously characterized functional domain. Sequence analysis of the N-terminal domain of land plant CK2β subunit sequences reveals its arrangement through short, conserved motifs, some of them including CK2 autophosphorylation sites. By using maize CK2β1 and a deleted version (ΔNCK2β1) lacking the N-terminal domain, we have demonstrated that CK2β1 is autophosphorylated within the N-terminal domain. Moreover, the holoenzyme composed with CK2α1/ΔNCK2β1 is able to phosphorylate different substrates more efficiently than CK2α1/CK2β1 or CK2α alone. Transient overexpression of CK2β1 and ΔNCK2β1 fused to GFP in different plant systems show that the presence of N-terminal domain enhances aggregation in nuclear speckles and stabilizes the protein against proteasome degradation. Finally, bimolecular fluorescence complementation (BiFC) assays show the nuclear and cytoplasmic location of the plant CK2 holoenzyme, in contrast to the individual CK2α/β subunits mainly observed in the nucleus. All together, our results support the hypothesis that the plant-specific N-terminal domain of CK2β subunits is involved in the down-regulation of the CK2 holoenzyme activity and in the stabilization of CK2β1 protein. In summary, the whole amount of data shown in this work suggests that this domain was acquired by plants for regulatory purposes. PMID:21789193

The Impact of Bars and Spiral Density Waves on the Relative Frequencies of Supernovae

NASA Astrophysics Data System (ADS)

Aramyan, L. S.; Hakobyan, A. A.; Petrosian, A. R.; Barkhudaryan, L. V.; Karapetyan, A. G.; Adibekyan, V.; Turatto, M.

2017-07-01

We present the results of the analysis of the impact of bars and spiral density waves on the relative frequencies of supernovae (SNe). We find that for early -type Grand-Design (GD) and non-Grand-Design (NGD) galaxies, the NIa/NCC ratios, i.e., one of the tracers of specific star formation rate (sSFR), are not significantly different between barred and unbarred hosts. At the same time, for both barred and unbarred early-type galaxies, the NIa /NCC ratio in NGD hosts is significantly higher than that in GD, and for late-type galaxies no any significant difference exists between the N Ia/NCC ratios. Thus, in contrast to bars, the spiral density waves significantly enhance the relative frequencies of SNe in early-type GD galaxies, while not in late-type hosts. This result is actual also for galaxies when barred and unbarred categories are separated. Hence, the sSFR might be enhanced by density waves in early-type galaxies only.

Prevalence of and Differences in Salad Bar Implementation in Rural Versus Urban Arizona Schools.

PubMed

Blumenschine, Michelle; Adams, Marc; Bruening, Meg

2018-03-01

Rural children consume more calories per day on average than urban children, and they are less likely to consume fruit. Self-service salad bars have been proposed as an effective approach to better meet the National School Lunch Program's fruit and vegetable recommendations. No studies have examined how rural and urban schools differ in the implementation of school salad bars. To compare the prevalence of school-lunch salad bars and differences in implementation between urban and rural Arizona schools. Secondary analysis of a cross-sectional web-based survey. School nutrition managers (N=596) in the state of Arizona. National Center for Education Statistics locale codes defined rural and urban classifications. Barriers to salad bar implementation were examined among schools that have never had, once had, and currently have a school salad bar. Promotional practices were examined among schools that once had and currently have a school salad bar. Generalized estimating equation models were used to compare urban and rural differences in presence and implementation of salad bars, adjusting for school-level demographics and the clustering of schools within districts. After adjustment, the prevalence of salad bars did not differ between urban and rural schools (46.9%±4.3% vs 46.8%±8.5%, respectively). Rural schools without salad bars more often reported perceived food waste and cost of produce as barriers to implementing salad bars, and funding was a necessary resource for offering a salad bar in the future, as compared with urban schools (P<0.05). No other geographic differences were observed in reported salad bar promotion, challenges, or resources among schools that currently have or once had a salad bar. After adjustment, salad bar prevalence, implementation practices, and concerns are similar across geographic settings. Future research is needed to investigate methods to address cost and food waste concerns in rural areas. Copyright © 2018 Academy of Nutrition and

The intrinsic three-dimensional shape of galactic bars

NASA Astrophysics Data System (ADS)

Méndez-Abreu, J.; Costantin, L.; Aguerri, J. A. L.; de Lorenzo-Cáceres, A.; Corsini, E. M.

2018-06-01

We present the first statistical study on the intrinsic three-dimensional (3D) shape of a sample of 83 galactic bars extracted from the CALIFA survey. We use the galaXYZ code to derive the bar intrinsic shape with a statistical approach. The method uses only the geometric information (ellipticities and position angles) of bars and discs obtained from a multi-component photometric decomposition of the galaxy surface-brightness distributions. We find that bars are predominantly prolate-triaxial ellipsoids (68%), with a small fraction of oblate-triaxial ellipsoids (32%). The typical flattening (intrinsic C/A semiaxis ratio) of the bars in our sample is 0.34, which matches well the typical intrinsic flattening of stellar discs at these galaxy masses. We demonstrate that, for prolate-triaxial bars, the intrinsic shape of bars depends on the galaxy Hubble type and stellar mass (bars in massive S0 galaxies are thicker and more circular than those in less massive spirals). The bar intrinsic shape correlates with bulge, disc, and bar parameters. In particular with the bulge-to-total (B/T) luminosity ratio, disc g - r color, and central surface brightness of the bar, confirming the tight link between bars and their host galaxies. Combining the probability distributions of the intrinsic shape of bulges and bars in our sample we show that 52% (16%) of bulges are thicker (flatter) than the surrounding bar at 1σ level. We suggest that these percentages might be representative of the fraction of classical and disc-like bulges in our sample, respectively.

Development of ceramic-coated weld backing bars

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eggleston, B.R.

1994-10-20

In shipbuilding and many other industries, copper weld backing bars are used to draw the heat out of the weld. The problem that some users of these bars encounter is that these bars, on occasion, actually melt in spots and become welded to the weld plates. After this happens a number of times, the backing bar becomes so degraded that it must be either discarded or machined, both of which are very costly and time-consuming actions. To avoid this fusion between the backing bar and the weld plate, the weld processes that are used cannot be ones of high beatmore » input. This requirement is very limiting when thick plates are being welded. The plates must be beveled, and more weld passes must be run. These problems are also costly and time consuming. The aim of this project is to find a way to produce backing bars with nearly the same `chilling` effect but with both a greater resistance to molten metal and resistance to arcing to the backing bar itself. A possible solution currently being tested is to coat the copper bars with a thin layer of a ceramic coating. The procedure used was to coat the copper bars with either alumina or spinel by a plasma spraying method.« less

Unit-bar migration and bar-trough deposition: impacts on hydraulic conductivity and grain size heterogeneity in a sandy streambed

NASA Astrophysics Data System (ADS)

Korus, Jesse T.; Gilmore, Troy E.; Waszgis, Michele M.; Mittelstet, Aaron R.

2018-03-01

The hydrologic function of riverbeds is greatly dependent upon the spatiotemporal distribution of hydraulic conductivity and grain size. Vertical hydraulic conductivity ( K v) is highly variable in space and time, and controls the rate of stream-aquifer interaction. Links between sedimentary processes, deposits, and K v heterogeneity have not been well established from field studies. Unit bars are building blocks of fluvial deposits and are key to understanding controls on heterogeneity. This study links unit bar migration to K v and grain size variability in a sand-dominated, low-sinuosity stream in Nebraska (USA) during a single 10-day hydrologic event. An incipient bar formed parallel to the thalweg and was highly permeable and homogenous. During high flow, this bar was submerged under 10-20 cm of water and migrated 100 m downstream and toward the channel margin, where it became markedly heterogeneous. Low- K v zones formed in the subsequent heterogeneous bar downstream of the original 15-40-cm-thick bar front and past abandoned bridge pilings. These low- K v zones correspond to a discontinuous 1-cm layer of fine sand and silt deposited in the bar trough. Findings show that K v heterogeneity relates chiefly to the deposition of suspended materials in low-velocity zones downstream of the bar and obstructions, and to their subsequent burial by migration of the bar during high flow. Deposition of the unit bar itself, although it emplaced the vast majority of the sediment volume, was secondary to bar-trough deposition as a control on the overall pattern of heterogeneity.

N-terminal Domains Elicit Formation of Functional Pmel17 Amyloid Fibrils*

PubMed Central

Watt, Brenda; van Niel, Guillaume; Fowler, Douglas M.; Hurbain, Ilse; Luk, Kelvin C.; Stayrook, Steven E.; Lemmon, Mark A.; Raposo, Graça; Shorter, James; Kelly, Jeffery W.; Marks, Michael S.

2009-01-01

Pmel17 is a transmembrane protein that mediates the early steps in the formation of melanosomes, the subcellular organelles of melanocytes in which melanin pigments are synthesized and stored. In melanosome precursor organelles, proteolytic fragments of Pmel17 form insoluble, amyloid-like fibrils upon which melanins are deposited during melanosome maturation. The mechanism(s) by which Pmel17 becomes competent to form amyloid are not fully understood. To better understand how amyloid formation is regulated, we have defined the domains within Pmel17 that promote fibril formation in vitro. Using purified recombinant fragments of Pmel17, we show that two regions, an N-terminal domain of unknown structure and a downstream domain with homology to a polycystic kidney disease-1 repeat, efficiently form amyloid in vitro. Analyses of fibrils formed in melanocytes confirm that the polycystic kidney disease-1 domain forms at least part of the physiological amyloid core. Interestingly, this same domain is also required for the intracellular trafficking of Pmel17 to multivesicular compartments within which fibrils begin to form. Although a domain of imperfect repeats (RPT) is required for fibril formation in vivo and is a component of fibrils in melanosomes, RPT is not necessary for fibril formation in vitro and in isolation is unable to adopt an amyloid fold in a physiologically relevant time frame. These data define the structural core of Pmel17 amyloid, imply that the RPT domain plays a regulatory role in timing amyloid conversion, and suggest that fibril formation might be physically linked with multivesicular body sorting. PMID:19840945

Identification of YTH Domain-Containing Proteins as the Readers for N1-Methyladenosine in RNA.

PubMed

Dai, Xiaoxia; Wang, Tianlu; Gonzalez, Gwendolyn; Wang, Yinsheng

2018-06-05

N1-methyladenosine (m 1 A) is an important post-transcriptional modification in RNA; however, the exact biological role of m 1 A remains to be determined. By employing a quantitative proteomics method, we identified multiple putative protein readers of m 1 A in RNA, including several YTH domain family proteins. We showed that YTHDF1-3 and YTHDC1, but not YTHDC2, could bind directly to m 1 A in RNA. We also found that Trp 432 in YTHDF2, a conserved residue in the hydrophobic pocket of the YTH domain that is necessary for its binding to N 6 -methyladenosine (m 6 A), is required for its recognition of m 1 A. An analysis of previously published data revealed transcriptome-wide colocalization of YTH domain-containing proteins and m 1 A sites in HeLa cells, suggesting that YTH domain-containing proteins can bind to m 1 A in cells. Together, our results uncovered YTH domain-containing proteins as readers for m 1 A in RNA and provided new insight into the functions of m 1 A in RNA biology.

Direct observation of magnetic domains by Kerr microscopy in a Ni-Mn-Ga magnetic shape-memory alloy

NASA Astrophysics Data System (ADS)

Perevertov, O.; Heczko, O.; Schäfer, R.

2017-04-01

The magnetic domains in a magnetic shape-memory Ni-Mn-Ga alloy were observed by magneto-optical Kerr microscopy using monochromatic blue LED light. The domains were observed for both single- and multivariant ferroelastic states of modulated martensite. The multivariant state with very fine twins was spontaneously formed after transformation from high-temperature austenite. For both cases, bar domains separated by 180∘ domain walls were found and their dynamics was studied. A quasidomain model was applied to explain the domains in the multivariant state.

Structure and catalytic regulatory function of ubiquitin specific protease 11 N-terminal and ubiquitin-like domains.

PubMed

Harper, Stephen; Gratton, Hayley E; Cornaciu, Irina; Oberer, Monika; Scott, David J; Emsley, Jonas; Dreveny, Ingrid

2014-05-13

The ubiquitin specific protease 11 (USP11) is implicated in DNA repair, viral RNA replication, and TGFβ signaling. We report the first characterization of the USP11 domain architecture and its role in regulating the enzymatic activity. USP11 consists of an N-terminal "domain present in USPs" (DUSP) and "ubiquitin-like" (UBL) domain, together referred to as DU domains, and the catalytic domain harboring a second UBL domain. Crystal structures of the DU domains show a tandem arrangement with a shortened β-hairpin at the two-domain interface and altered surface characteristics compared to the homologues USP4 and USP15. A conserved VEVY motif is a signature feature at the two-domain interface that shapes a potential protein interaction site. Small angle X-ray scattering and gel filtration experiments are consistent with the USP11DU domains and full-length USP11 being monomeric. Unexpectedly, we reveal, through kinetic assays of a series of deletion mutants, that the catalytic activity of USP11 is not regulated through intramolecular autoinhibition or activation by the N-terminal DU or UBL domains. Moreover, ubiquitin chain cleavage assays with all eight linkages reveal a preference for Lys(63)-, Lys(6)-, Lys(33)-, and Lys(11)-linked chains over Lys(27)-, Lys(29)-, and Lys(48)-linked and linear chains consistent with USP11's function in DNA repair pathways that is mediated by the protease domain. Our data support a model whereby USP11 domains outside the catalytic core domain serve as protein interaction or trafficking modules rather than a direct regulatory function of the proteolytic activity. This highlights the diversity of USPs in substrate recognition and regulation of ubiquitin deconjugation.

Feasibility and acceptability of a bar-based sexual risk reduction intervention for bar patrons in Tshwane, South Africa.

PubMed

Morojele, Neo K; Kitleli, Naledi; Ngako, Kgalabi; Kekwaletswe, Connie T; Nkosi, Sebenzile; Fritz, Katherine; Parry, Charles D H

2014-01-01

Alcohol consumption is a recognised risk factor for HIV infection. Alcohol serving establishments have been identified as appropriate venues in which to deliver HIV prevention interventions. This paper describes experiences and lessons learnt from implementing a combined HIV prevention intervention in bar settings in one city- and one township-based bar in Tshwane, South Africa. The intervention consisted of peer-led and brief intervention counselling sub-components. Thirty-nine bar patrons were recruited and trained, and delivered HIV and alcohol risk reduction activities to their peers as peer interventionists. At the same time, nine counsellors received training and visited the bars weekly to provide brief motivational interviewing counselling, advice, and referrals to the patrons of the bars. A responsible server sub-component that had also been planned was not delivered as it was not feasible to train the staff in the two participating bars. Over the eight-month period the counsellors were approached by and provided advice and counselling for alcohol and sexual risk-related problems to 111 bar patrons. The peer interventionists reported 1323 risk reduction interactions with their fellow bar patrons during the same period. The intervention was overall well received and suggests that bar patrons and servers can accept a myriad of intervention activities to reduce sexual risk behaviour within their drinking settings. However, HIV- and AIDS-related stigma hindered participation in certain intervention activities in some instances. The buy-in that we received from the relevant stakeholders (i.e. bar owners/managers and patrons, and the community at large) was an important contributor to the feasibility and acceptability of the intervention.

Feasibility and acceptability of a bar-based sexual risk reduction intervention for bar patrons in Tshwane, South Africa

PubMed Central

Morojele, Neo K.; Kitleli, Naledi; Ngako, Kgalabi; Kekwaletswe, Connie T.; Nkosi, Sebenzile; Fritz, Katherine; Parry, Charles D.H.

2014-01-01

Abstract Alcohol consumption is a recognised risk factor for HIV infection. Alcohol serving establishments have been identified as appropriate venues in which to deliver HIV prevention interventions. This paper describes experiences and lessons learnt from implementing a combined HIV prevention intervention in bar settings in one city- and one township-based bar in Tshwane, South Africa. The intervention consisted of peer-led and brief intervention counselling sub-components. Thirty-nine bar patrons were recruited and trained, and delivered HIV and alcohol risk reduction activities to their peers as peer interventionists. At the same time, nine counsellors received training and visited the bars weekly to provide brief motivational interviewing counselling, advice, and referrals to the patrons of the bars. A responsible server sub-component that had also been planned was not delivered as it was not feasible to train the staff in the two participating bars. Over the eight-month period the counsellors were approached by and provided advice and counselling for alcohol and sexual risk-related problems to 111 bar patrons. The peer interventionists reported 1323 risk reduction interactions with their fellow bar patrons during the same period. The intervention was overall well received and suggests that bar patrons and servers can accept a myriad of intervention activities to reduce sexual risk behaviour within their drinking settings. However, HIV- and AIDS-related stigma hindered participation in certain intervention activities in some instances. The buy-in that we received from the relevant stakeholders (i.e. bar owners/managers and patrons, and the community at large) was an important contributor to the feasibility and acceptability of the intervention. PMID:24750106

A unique GCN5-related glucosamine N-acetyltransferase region exist in the fungal multi-domain glycoside hydrolase family 3 β-N-acetylglucosaminidase

PubMed Central

Qin, Zhen; Xiao, Yibei; Yang, Xinbin; Mesters, Jeroen R.; Yang, Shaoqing; Jiang, Zhengqiang

2015-01-01

Glycoside hydrolase (GH) family 3 β-N-acetylglucosaminidases widely exist in the filamentous fungi, which may play a key role in chitin metabolism of fungi. A multi-domain GH family 3 β-N-acetylglucosaminidase from Rhizomucor miehei (RmNag), exhibiting a potential N-acetyltransferase region, has been recently reported to show great potential in industrial applications. In this study, the crystal structure of RmNag was determined at 2.80 Å resolution. The three-dimensional structure of RmNag showed four distinctive domains, which belong to two distinguishable functional regions — a GH family 3 β-N-acetylglucosaminidase region (N-terminal) and a N-acetyltransferase region (C-terminal). From structural and functional analysis, the C-terminal region of RmNag was identified as a unique tandem array linking general control non-derepressible 5 (GCN5)-related N-acetyltransferase (GNAT), which displayed glucosamine N-acetyltransferase activity. Structural analysis of this glucosamine N-acetyltransferase region revealed that a unique glucosamine binding pocket is located in the pantetheine arm binding terminal region of the conserved CoA binding pocket, which is different from all known GNAT members. This is the first structural report of a glucosamine N-acetyltransferase, which provides novel structural information about substrate specificity of GNATs. The structural and functional features of this multi-domain β-N-acetylglucosaminidase could be useful in studying the catalytic mechanism of GH family 3 proteins. PMID:26669854

Promoter-dependent activity on androgen receptor N-terminal domain mutations in androgen insensitivity syndrome.

PubMed

Tadokoro-Cuccaro, Rieko; Davies, John; Mongan, Nigel P; Bunch, Trevor; Brown, Rosalind S; Audi, Laura; Watt, Kate; McEwan, Iain J; Hughes, Ieuan A

2014-01-01

Androgen receptor (AR) mutations are associated with androgen insensitivity syndrome (AIS). Missense mutations identified in the AR-N-terminal domain (AR-NTD) are rare, and clinical phenotypes are typically mild. We investigated 7 missense mutations and 2 insertion/deletions located in the AR-NTD. This study aimed to elucidate the pathogenic role of AR-NTD mutants in AIS and to use this knowledge to further define AR-NTD function. AR-NTD mutations (Q120E, A159T, G216R, N235K, G248V, L272F, and P380R) were introduced into AR-expression plasmids. Stably expressing cell lines were established for del57L and ins58L. Transactivation was measured using luciferase reporter constructs under the control of GRE and Pem promoters. Intrinsic fluorescence spectroscopy and partial proteolysis studies were performed for mutations which showed reduced activities by using a purified AR-AF1 protein. Pem-luciferase reporter activation was reduced for A159T, N235K, and G248V but not the GRE-luciferase reporter. Protein structure analysis detected no significant change in the AR-AF1 region for these mutations. Reduced cellular expression and transactivation activity were observed for ins58L. The mutations Q120E, G216R, L272F, P380R, and del57L showed small or no detectable changes in function. Thus, clinical and experimental analyses have identified novel AR-signalling defects associated with mutations in the structurally disordered AR-NTD domain in patients with AIS. © 2014 S. Karger AG, Basel.

Secondhand smoke exposure in bars and restaurants in Guatemala City: before and after smoking ban evaluation.

PubMed

Barnoya, Joaquin; Arvizu, Mariel; Jones, Miranda R; Hernandez, Juan C; Breysse, Patrick N; Navas-Acien, Ana

2011-01-01

In February 2009, Guatemala implemented a comprehensive smoking ban. We assessed air nicotine levels in bars and restaurants 6 months after the ban (post-ban) and compared them with levels found in 2006 (pre-ban). Exposure was estimated by passive sampling of vapor-phase nicotine using samplers (n=50) placed for 7 working days in 10 bars and 11 restaurants in Guatemala City. Air nicotine was measured by gas chromatography, and the time-weighted average concentration in μg/m(3) was estimated. Employees answered a survey about smoke-free workplaces (n = 32) and compared with pre-ban (n = 37) results. Nicotine was detectable in all bars pre- and post-ban. In restaurants, it was detectable in all pre- and 73% post-ban. Median nicotine concentrations in bars significantly decreased from 4.58 μg/m(3) (IQR, 1.71, 6.45) pre-ban to 0.28 μg/m(3) (IQR 0.17, 0.66) post-ban (87% decrease). In restaurants, concentrations significantly decreased from 0.58 μg/m(3) (IQR, 0.44, 0.71) to 0.04 μg/m(3) (IQR 0.01, 0.11) (95% decrease). Employees' support for a smoke-free workplace increased in the post-ban survey (from 32 to 81%, p < 0.001). Six months after the implementation of a smoke-free law in Guatemala, nicotine levels were significantly decreased in bars and restaurants and workers' support for the law substantially increased.

Effects of bilateral swing-away grab bars on the biomechanics of stand-to-sit and sit-to-stand toilet transfers.

PubMed

Lee, Su Jin; Mehta-Desai, Ricky; Oh, Kyunggeune; Sanford, Jon; Prilutsky, Boris I

2018-03-09

Kinetic characteristics of transfers to and from a toilet performed using bilateral grab bars are not fully quantified to inform grab bar design and configuration. The purpose of this study was to (1) determine effects of bilateral swing-away grab bars on peaks of ankle, knee and hip joint moments during grab bar assisted stand-to-sit and sit-to-stand transfers; and (2) determine effects of three different heights and widths of swing-away grab bars on the same kinetic characteristics. Healthy subjects (N = 11, age 25-58 years) performed stand-to-sit and sit-to-stand transfers with and without grab bars. In transfers with grab bars, 9 grab bar configurations were tested by varying their height from the floor (0.787 m, 0.813 m, 0.838 m; 31″-33″) and width, the distance of each grab bar from the toilet's centerline (0.330 m, 0.356 m, 0.381 m; 13″-15″). Motion capture, force plate and inverse dynamics analysis were used to determine lower limb joint moments. The use of bilateral grab bars generally reduced the peak magnitude of extension moments at lower limb joints during stand-to-sit and sit-to-stand transfers (p < .05), except the ankle joint moments during stand-to-sit transfers. Relatively few differences in peak joint moments were found between studied grab bar widths or heights. The obtained results suggest that the studied ranges of grab bar configurations reduce moment demands on the leg joints and thus decrease difficulty and required lower limb muscle effort to perform the transfers. Implications for Rehabilitation Maximizing the benefits of assistive technology in the built environment requires a careful assessment of their spatial and configurational dimensions, especially in respect to the needs and abilities of the intended users. Examining the kinetic characteristics of transfers to and from a toilet using the swing-away grab bars is useful for informing grab bar design and configuration recommendations for assisted living

Evidence for new resonances in the K-barN system: A prima facie case for the even-wave harmonic-oscillator model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kamath, S.G.

1978-10-01

Arguments are presented to show that the new resonance parameters obtained by Alston-Garnjost et al. in a recent analysis of the K-barN system from 365 to 1320 MeV/c provide a prima facie case for the even-wave harmonic-oscillator theory of baryonic states in the framework of SU(6)/sub W/ x O(3). A new quantum classification of the ..lambda.. states belonging to the (70,1/sup -/) is also proposed.

Implementation of the P barANDA Planar-GEM tracking detector in Monte Carlo simulations

NASA Astrophysics Data System (ADS)

Divani Veis, Nazila; Ehret, Andre; Firoozabadi, Mohammad M.; Karabowicz, Radoslaw; Maas, Frank; Saito, Nami; Saito, Takehiko R.; Voss, Bernd; PANDA Gem-Tracker Subgroup

2018-02-01

The P barANDA experiment at FAIR will be performed to investigate different aspects of hadron physics using anti-proton beams interacting with a fixed nuclear target. The experimental setup consists of a complex series of detector components covering a large solid angle. A detector with a gaseous active media equipped with gas electron multiplier (GEM) technique will be employed to measure tracks of charged particles at forward direction in order to achieve a high momentum resolution. In this work, a full setup of the GEM tracking detector has been implemented in the P barANDA Monte Carlo simulation package (PandaRoot) based on the current technical and conceptual design, and the expected performance of the P barANDA GEM-tracking detector has been investigated. Furthermore, material-budget studies in terms of the radiation length of the P barANDA GEM-tracking detector have been made in order to investigate the effect of the detector materials and its associated structures to particle measurements.

The origin of the LMC stellar bar: clues from the SFH of the bar and inner disc

NASA Astrophysics Data System (ADS)

Monteagudo, L.; Gallart, C.; Monelli, M.; Bernard, E. J.; Stetson, P. B.

2018-01-01

We discuss the origin of the Large Magellanic Cloud (LMC) stellar bar by comparing the star formation histories (SFHs) obtained from deep colour-magnitude diagrams (CMDs) in the bar and in a number of fields in different directions within the inner disc. The CMDs, reaching the oldest main-sequence turn-offs in these very crowded fields, have been obtained with VIMOS on the Very Large Telescope in the service mode, under very good seeing conditions. We show that the SFHs of all fields share the same patterns, with consistent variations of the star formation rate as a function of time in all of them. We therefore conclude that no specific event of star formation can be identified with the formation of the LMC bar, which instead likely formed from a redistribution of disc material which occurred when the LMC disc became bar unstable, and shared a common SFH with the inner disc thereafter. The strong similarity between the SFH of the centre and edge of the bar rules out the expected significant spatial variations of the SFH across the bar.

The Potential Power of Bar-HRM Technology in Herbal Medicine Identification

PubMed Central

Sun, Wei; Li, Jing-jian; Xiong, Chao; Zhao, Bo; Chen, Shi-lin

2016-01-01

The substitution of low-cost or adulterated herbal products for high-priced herbs makes it important to be able to identify and trace herbal plant species and their processed products in the drug supply chain. PCR-based methods play an increasing role in monitoring the safety of herbal medicines by detecting adulteration. Recent studies have shown the potential of DNA barcoding combined with high resolution melting (Bar-HRM) analysis in herbal medicine identification. This method involves precisely monitoring the change in fluorescence caused by the release of an intercalating DNA dye from a DNA duplex as it is denatured by a gradual increase in temperature. Since the melting profile depends on the GC content, length, and strand complementarity of the amplification product, Bar-HRM analysis opens up the possibility of detecting single-base variants or species-specific differences in a short region of DNA. This review summarizes key factors affecting Bar-HRM analysis and describes how Bar-HRM is performed. We then discuss advances in Bar-HRM analysis of medicinal plant ingredients (herbal materia medica) as a contribution toward safe and effective herbal medicines. PMID:27066026

The Potential Power of Bar-HRM Technology in Herbal Medicine Identification.

PubMed

Sun, Wei; Li, Jing-Jian; Xiong, Chao; Zhao, Bo; Chen, Shi-Lin

2016-01-01

The substitution of low-cost or adulterated herbal products for high-priced herbs makes it important to be able to identify and trace herbal plant species and their processed products in the drug supply chain. PCR-based methods play an increasing role in monitoring the safety of herbal medicines by detecting adulteration. Recent studies have shown the potential of DNA barcoding combined with high resolution melting (Bar-HRM) analysis in herbal medicine identification. This method involves precisely monitoring the change in fluorescence caused by the release of an intercalating DNA dye from a DNA duplex as it is denatured by a gradual increase in temperature. Since the melting profile depends on the GC content, length, and strand complementarity of the amplification product, Bar-HRM analysis opens up the possibility of detecting single-base variants or species-specific differences in a short region of DNA. This review summarizes key factors affecting Bar-HRM analysis and describes how Bar-HRM is performed. We then discuss advances in Bar-HRM analysis of medicinal plant ingredients (herbal materia medica) as a contribution toward safe and effective herbal medicines.

Effects of grab bar on utilized friction and dynamic stability when elderly people enter the bathtub.

PubMed

Sekiguchi, Yusuke; Kato, Tomohisa; Honda, Keita; Kanetaka, Hiroyasu; Izumi, Shin-Ichi

2017-08-01

The effect of the grab bar on dynamic stability when elderly people enter the bathtub remains unclear. The purpose of the present study is to examine the age-related effect of the grab bar on dynamic stability during lateral stepping over an obstacle when entering bathtub. Sixteen young, healthy adults and sixteen elderly adults participated. The subjects performed lateral stepping over an obstacle with and without vertical and horizontal bars. Displacement and velocity of the center of mass and utilized friction, which is the required coefficient of friction to avoid slipping, were simultaneously measured by a three-dimensional motion analysis system and two force plates. A post hoc test for two-way ANOVA revealed that velocity of the center of mass in the vertical direction (p<0.05) and peak-to-peak values of the center of mass in the lateral (p<0.05) and vertical directions (p<0.05) with each grab bar were significantly slower and smaller than those without the grab bar in young and elderly people. Moreover, the utilized friction at push off of the trailing leg with the vertical bar in elderly people was lower (p<0.05) than that in participants without the grab bar. The use of each grab bar while performing a lateral step over an obstacle may help maintaining balance in lateral and vertical directions. However, use of the vertical bar while lateral stepping over an object in elderly people may need low utilized friction to prevent slipping. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Effects of Item Format and Cognitive Domain on Students' Science Performance in TIMSS 2011

NASA Astrophysics Data System (ADS)

Liou, Pey-Yan; Bulut, Okan

2017-12-01

The purpose of this study was to examine eighth-grade students' science performance in terms of two test design components, item format, and cognitive domain. The portion of Taiwanese data came from the 2011 administration of the Trends in International Mathematics and Science Study (TIMSS), one of the major international large-scale assessments in science. The item difficulty analysis was initially applied to show the proportion of correct items. A regression-based cumulative link mixed modeling (CLMM) approach was further utilized to estimate the impact of item format, cognitive domain, and their interaction on the students' science scores. The results of the proportion-correct statistics showed that constructed-response items were more difficult than multiple-choice items, and that the reasoning cognitive domain items were more difficult compared to the items in the applying and knowing domains. In terms of the CLMM results, students tended to obtain higher scores when answering constructed-response items as well as items in the applying cognitive domain. When the two predictors and the interaction term were included together, the directions and magnitudes of the predictors on student science performance changed substantially. Plausible explanations for the complex nature of the effects of the two test-design predictors on student science performance are discussed. The results provide practical, empirical-based evidence for test developers, teachers, and stakeholders to be aware of the differential function of item format, cognitive domain, and their interaction in students' science performance.

BaBar Experiment Public Web Site

Science.gov Websites

spotlights BaBar time-reversal measurement. December 14, 2012 PhysicsWorld.com has selected the BaBar time . BaBar Makes First Direct Observation of Time-Reversal Violation August 30, 2012 Fundamental interactions among particles are oblivious to the direction of time (a movie of a rock thrown up and falling back

C18-coated stir bar sorptive extraction combined with high performance liquid chromatography-electrospray tandem mass spectrometry for the analysis of sulfonamides in milk and milk powder.

PubMed

Yu, Chunhe; Hu, Bin

2012-02-15

A simple, rapid, sensitive, inexpensive and less sample consuming method of C(18)-stir bar sorptive extraction (SBSE)-high performance liquid chromatography (HPLC)-tandem mass spectrometry (MS/MS) was proposed for the determination of six sulfonamides in milk and milk powder samples. C(18) silica particles coated stir bar was prepared by adhesion method, and two kinds of adhesive glue, polydimethylsiloxane (PDMS) sol and epoxy glue were tried. It was found that the C(18)-coated stir bar prepared by PDMS sol as adhesive glue is more robust than that prepared by epoxy glue when liquid desorption was employed, in terms of both lifetime and organic solvent tolerance. The preparation of C(18) stir bar was simple with good mechanic strength and the stir bar could be reused for more than 20 times. Granular coating has relatively high specific surface area and is propitious to sorptive extraction based process. Compared to conventional PDMS SBSE coating, C(18) coating shows good affinity to the target polar/weak polar sulfonamides. To achieve optimum SBSE extraction performance, several parameters including extraction and desorption time, ionic strength, sample pH and stirring speed were investigated. The detection limits of the proposed method for six sulfonamides were in the range of 0.9-10.5 μg/L for milk and 2.7-31.5 μg/kg for milk powder. Good linearities were obtained for sulfonamides with the correlation coefficients (R) above 0.9922. Finally, the proposed method was successfully applied to the determination of sulfonamides in milk and milk powder samples and satisfied recoveries of spiked target compounds in real samples were obtained. Copyright © 2012 Elsevier B.V. All rights reserved.

The Design and Development of a Potent and Selective Novel Diprolyl Derivative That Binds to the N-Domain of Angiotensin-I Converting Enzyme.

PubMed

Fienberg, Stephen; Cozier, Gyles E; Acharya, K Ravi; Chibale, Kelly; Sturrock, Edward D

2018-01-11

Angiotensin-I converting enzyme (ACE) is a zinc metalloprotease consisting of two catalytic domains (N- and C-). Most clinical ACE inhibitor(s) (ACEi) have been shown to inhibit both domains nonselectively, resulting in adverse effects such as cough and angioedema. Selectively inhibiting the individual domains is likely to reduce these effects and potentially treat fibrosis in addition to hypertension. ACEi from the GVK Biosciences database were inspected for possible N-domain selective binding patterns. From this set, a diprolyl chemical series was modeled using docking simulations. The series was expanded based on key target interactions involving residues known to impart N-domain selectivity. In total, seven diprolyl compounds were synthesized and tested for N-domain selective ACE inhibition. One compound with an aspartic acid in the P 2 position (compound 16) displayed potent inhibition (K i = 11.45 nM) and was 84-fold more selective toward the N-domain. A high-resolution crystal structure of compound 16 in complex with the N-domain revealed the molecular basis for the observed selectivity.

Graphene oxide/polyethyleneglycol composite coated stir bar for sorptive extraction of fluoroquinolones from chicken muscle and liver.

PubMed

Fan, Wenying; He, Man; Wu, Xiaoran; Chen, Beibei; Hu, Bin

2015-10-30

Graphene oxide (GO) is an ideal adsorbent for polar and less polar compounds due to its hexagonal carbon network structure with oxygen-containing groups, while its strong hydrophilicity and water solubility limited its application in sample pretreatment techniques. Herein, GO was composited with polyethyleneglycol (PEG) or polyaniline (PAN) through intermolecular interactions to improve its stability, and the GO/PEG and GO/PAN composite coated stir bars were prepared by sol-gel technique. Compared with GO/PAN composite and polydimethylsiloxane (PDMS) coated stir bar, the prepared GO/PEG composite coated stir bar exhibited higher extraction efficiency for five fluoroquinolones (FQs). Based on it, a method of GO/PEG composite coated stir bar sorptive extraction (SBSE) combined with high-performance liquid chromatography-fluorescence detector (HPLC-FLD) was proposed. The factors influencing SBSE, such as sample pH, salt effect, stirring rate, extraction time, desorption solvent and desorption time, were optimized, and the analytical performance of the developed SBSE-HPLC-FLD method was evaluated. The limits of detection (LODs) for five FQs were in the range of 0.0045-0.0079μgL(-1), and the enrichment factors (EFs) were in the range of 41.5-65.5-fold (theoretical enrichment factor was 100-fold). The reproducibility was also investigated at concentrations of 0.05μgL(-1) and the relative standard deviations (RSDs, n=6) were found to be in the range of 4.6-12.1%. The proposed method was successfully applied for the determination of FQs in chicken muscle and chicken liver samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Missense Mutations in the N-Terminal Domain of Human Phenylalanine Hydroxylase Interfere with Binding of Regulatory Phenylalanine

PubMed Central

Gjetting, Torben; Petersen, Marie; Guldberg, Per; Güttler, Flemming

2001-01-01

Hyperphenylalaninemia due to a deficiency of phenylalanine hydroxylase (PAH) is an autosomal recessive disorder caused by >400 mutations in the PAH gene. Recent work has suggested that the majority of PAH missense mutations impair enzyme activity by causing increased protein instability and aggregation. In this study, we describe an alternative mechanism by which some PAH mutations may render PAH defective. Database searches were used to identify regions in the N-terminal domain of PAH with homology to the regulatory domain of prephenate dehydratase (PDH), the rate-limiting enzyme in the bacterial phenylalanine biosynthesis pathway. Naturally occurring N-terminal PAH mutations are distributed in a nonrandom pattern and cluster within residues 46–48 (GAL) and 65–69 (IESRP), two motifs highly conserved in PDH. To examine whether N-terminal PAH mutations affect the ability of PAH to bind phenylalanine at the regulatory domain, wild-type and five mutant (G46S, A47V, T63P/H64N, I65T, and R68S) forms of the N-terminal domain (residues 2–120) of human PAH were expressed as fusion proteins in Escherichia coli. Binding studies showed that the wild-type form of this domain specifically binds phenylalanine, whereas all mutations abolished or significantly reduced this phenylalanine-binding capacity. Our data suggest that impairment of phenylalanine-mediated activation of PAH may be an important disease-causing mechanism of some N-terminal PAH mutations, which may explain some well-documented genotype-phenotype discrepancies in PAH deficiency. PMID:11326337

Amino modified multi-walled carbon nanotubes/polydimethylsiloxane coated stir bar sorptive extraction coupled to high performance liquid chromatography-ultraviolet detection for the determination of phenols in environmental samples.

PubMed

Hu, Cong; Chen, Beibei; He, Man; Hu, Bin

2013-07-26

In this work, amino modified multi-walled carbon nanotubes/polydimethylsiloxane (multi-walled carbon nanotubes-4,4'-diaminodiphenylmethane/polydimethylsiloxane, MWCNTs-DDM/PDMS) was synthesized, and utilized as a novel coating for stir bar sorptive extraction (SBSE) of seven phenols (phenol, 2-chlorophenol, 2-nitrophenol, 4-nitrophenol, 2,4-dimethylphenol, p-choro-m-cresol and 2,4,6-trichlorphenol) in environmental water and soil samples, followed by high performance liquid chromatography-ultraviolet detection (HPLC-UV). The prepared MWCNTs-DDM/PDMS coated stir bar was characterized and good preparation reproducibility was obtained with the relative standard deviations (RSDs) ranging from 4.7% to 11.3% (n=9) in one batch, and from 4.8% to 13.9% (n=8) among different batches. Several parameters affecting the extraction of seven target phenols by MWCNTs-DDM/PDMS-SBSE including extraction time, stirring rate, pH, ionic strength, desorption solvent and desorption time were investigated. Under the optimal experimental conditions, the limits of detection (LODs, S/N=3) were found to be in the range of 0.14μg/L (2-nitrophenol) to 1.76μg/L (phenol) and the limits of quantification (LOQs, S/N=10) were found to be in the range of 0.46μg/L (2-nitrophenol) to 5.8μg/L (phenol). The linear range was 5-1000μg/L for phenol and 4-nitrophenol, 1-1000μg/L for 2-nitrophenol and 2-1000μg/L for other phenols, respectively. The RSDs of the developed method were in the range of 6.2-11.6% (n=8, c=10μg/L) and the enrichment factors were from 6.5 to 62.8-fold (theoretical enrichment factor was 100-fold). The proposed method was successfully applied to the analysis of phenols in environmental water and soil samples, and good recoveries were obtained for the spiked samples. The proposed method is simple, highly sensitive and suitable for the analysis of trace phenols in environmental samples with complex matrix. Copyright © 2013 Elsevier B.V. All rights reserved.

Modulation and Functional Role of the Orientations of the N- and P-Domains of Cu+ -Transporting ATPase along the Ion Transport Cycle.

PubMed

Meng, Dan; Bruschweiler-Li, Lei; Zhang, Fengli; Brüschweiler, Rafael

2015-08-18

Ion transport of different P-type ATPases is regulated similarly through the interplay of multiple protein domains. In the presence of ATP, binding of a cation to the ion binding site in the transmembrane helices leads to the phosphorylation of the P-domain, allowing ion transfer across the membrane. The details of the mechanism, however, are not clear. Here, we report the modulation of the orientation between the N- and P-domains of Cu(+)-transporting ATPase along the ion transport cycle using high-resolution nuclear magnetic resonance spectroscopy in solution. On the basis of residual dipolar coupling measurements, it is found that the interdomain orientation (relative openness) of the N- and P-domains is distinctly modulated depending on the specific state of the N- and P-domains along the ion translocation cycle. The two domains' relative position in the apo state is semiopen, whereas it becomes closed upon binding of ATP to the N-domain. After phosphorylation of the P-domain and the release of ADP, the opening, however, becomes the widest among all the states. We reason such wide opening resulting from the departure of ADP prepares the N- and P-domains to accommodate the A-domain for interaction and, hence, promote ion transport and allow dephosphorylation of the P-domain. Such wide interdomain opening is abolished when an Asn to Asp mutation is introduced into the conserved DXXK motif located in the hinge region of the N- and P-domains of Cu(+)-ATPase, suggesting the indispensible role of the N- and P-interdomain orientation during ion transportation. Our results shed new light on the structural and mechanistic details of P-type ATPase function at large.

Influence of the weighing bar size to determine optimal time of biodiesel-glycerol separation by using the buoyancy weighing-bar method

NASA Astrophysics Data System (ADS)

Tambun, R.; Sibagariang, Y.; Manurung, J.

2018-02-01

The buoyancy weighing-bar method is a novel method in the particle size distribution measurement. This method can measure particle size distributions of the settling particles and floating particles. In this study, the buoyancy weighing-bar method is applied to determine optimal time of biodiesel-glycerol separation. The buoyancy weighing-bar method can be applied to determine the separation time because biodiesel and glycerol have the different densities. The influences of diameter of weighing-bar by using the buoyancy weighing-bar method would be experimentally investigated. The diameters of weighing-bar in this experiment are 8 mm, 10 mm, 15 mm and 20 mm, while the graduated cylinder (diameter : 65 mm) is used as vessel. The samples used in this experiment are the mixture of 95 % of biodiesel and 5 % of glycerol. The data obtained by the buoyancy weighing-bar method are analized by using the gas chromatography to determine the purity of biodiesel. Based on the data obtained, the buoyancy weighing-bar method can be used to detect the separation time of biodiesel-glycerol by using the weighing-bar diameter of 8 mm, 10 mm, 15 mm and 20 mm, but the most accuracy in determination the biodiesel-glycerol separation time is obtained by using the weighing-bar diameter of 20 mm. The biodiesel purity of 97.97 % could be detected at 64 minutes by using the buoyancy weighing-bar method when the weighing-bar diameter of 20 mm is used.

Correlation of Selected Subsize Charpy Bars versus the Standard Charpy Bar

DTIC Science & Technology

1958-05-01

WAL TR 112/91 TECIINICAL REPORT r- i -I WATERTOWN ARSENAL LABORATORI ES CORRELATION OF SELECTED SUBSIZE CHARPY BARS VERSUS THE STANDARD CHARPY BAR...DTIC BY fitELECTED CHARLES Ht. CURIL MAY 8 19813 GEORGE M. OR14ER 0.0. PROJECT: INDUSTRIAL PREPAREDNESS MEASURE, ,... DEVELOPMENT OF SUBSIZE CHARPY ...STANDARD P.E.S.D. NO.: 60302l281-16-65003 REPORT NO.: WAL TR 112191 FILING SUBJECT: SUBSIZE CHARPY IThis documnt~ has mo f1 P~ub1c teT -rie and mczlelIN

The influence of bar diameter on neuromuscular strength and activation: inferences from an isometric unilateral bench press.

PubMed

Fioranelli, Douglas; Lee, C Matthew

2008-05-01

The purpose of this study was to examine the influence of two different bar diameters on neuromuscular activation and strength. The bar diameters used reflected a standard Olympic bar (28 mm (1.1 inch); THIN) and a larger fat bar (51 mm [2 inch]; THICK). Eighteen healthy men (age 25.0 +/- 1 years) were assessed for their maximal voluntary contraction (MVC) during a unilateral isometric bench press exercise with the 2 bar types at 2 different joint angles (angle 1 and angle 2; elbow joint at approximately 45 and 90 degrees , respectively). Additionally, on a separate day, subjects performed three 10-second isometric repetitions at an intensity of 80% MVC using the 2 different bars at angle 1 and angle 2. Electromyographic recordings were collected in the pectoralis major and the muscles of the forearm flexor region at a sampling rate of 1000 Hz during the second day of testing. Analysis of variance was used to examine differences in MVC between bars and also examine between bar differences in electromyographic activity for each muscle group at each joint angle. A significance level of 0.05 was used for all tests. MVC was not different between bar types, although there was a main effect of joint angle on MVC such that it was greater at angle 2. There was a main effect of bar at both angles for the forearm muscles and at angle 1 for the pectoralis such that electromyographic activity was greater with THIN. Our data do not support the hypothesis that bar diameter influences performance during an isometric bench press exercise. However, higher electromyographic activity with THIN suggests greater neuromuscular activation with a standard Olympic bar as opposed to a larger diameter "fat" bar. Although our data do not support the use of a fat bar for increasing neuromuscular activation, these findings should be confirmed in other resistance training exercises.

Structural and motional contributions of the Bacillus subtilis ClpC N-domain in adaptor protein interactions

PubMed Central

Kojetin, Douglas J.; McLaughlin, Patrick D.; Thompson, Richele J.; Dubnau, David; Prepiak, Peter; Rance, Mark; Cavanagh, John

2009-01-01

Summary The AAA+ superfamily protein ClpC is a key regulator of cell development in Bacillus subtilis. As part of a large oligomeric complex, ClpC controls an array of cellular processes by recognizing, unfolding, and providing misfolded and aggregated proteins as substrates for the ClpP peptidase. ClpC is unique compared to other HSP100/Clp proteins, as it requires an adaptor protein for all fundamental activities. The NMR solution structure of the N-terminal repeat domain of ClpC (N-ClpCR) comprises two structural repeats of a four-helix motif. NMR experiments used to map the MecA adaptor protein interaction surface of N-ClpCR reveal that regions involved in the interaction possess conformational flexibility, as well as conformational exchange on the μs-ms time-scale. The electrostatic surface of N-ClpCR differs substantially compared to the N-domain of Escherichia coli ClpA and ClpB, suggesting that the electrostatic surface characteristics of HSP100/Clp N-domains may play a role in adaptor protein and substrate interaction specificity, and perhaps contribute to the unique adaptor protein requirement of ClpC. PMID:19361434

A Structure of a Collagen VI VWA Domain Displays N and C Termini at Opposite Sides of the Protein

PubMed Central

Becker, Ann-Kathrin A.; Mikolajek, Halina; Paulsson, Mats; Wagener, Raimund; Werner, Jörn M.

2014-01-01

Summary Von Willebrand factor A (VWA) domains are versatile protein interaction domains with N and C termini in close proximity placing spatial constraints on overall protein structure. The 1.2 Å crystal structures of a collagen VI VWA domain and a disease-causing point mutant show C-terminal extensions that place the N and C termini at opposite ends. This allows a “beads-on-a-string” arrangement of multiple VWA domains as observed for ten N-terminal domains of the collagen VI α3 chain. The extension is linked to the core domain by a salt bridge and two hydrophobic patches. Comparison of the wild-type and a muscular dystrophy-associated mutant structure identifies a potential perturbation of a protein interaction interface and indeed, the secretion of mutant collagen VI tetramers is affected. Homology modeling is used to locate a number of disease-associated mutations and analyze their structural impact, which will allow mechanistic analysis of collagen-VI-associated muscular dystrophy phenotypes. PMID:24332716

Comparison of near fusional vergence ranges with rotary prisms and with prism bars.

PubMed

Goss, David A; Becker, Emily

2011-02-01

Common methods for determination of fusional vergence ranges make use of rotary prisms in the phoropter or prism bars out of the phoropter. This study compared near fusional vergence ranges with rotary prisms with those with prism bars. Fifty young adults served as subjects. Odd-numbered subjects had rotary prism vergences performed before prism bar vergences. For even-numbered subjects, prism bar vergences were done first. Base-in (BI) vergences were done before base-out (BO) vergences with both rotary prisms and prism bars. A coefficient of agreement was calculated by multiplying the standard deviation of the individual subject differences between rotary prisms and prism bars by 1.96, to approximate the range within which the 2 tests would agree 95% of the time. The lowest coefficient of agreement was 7.3Δ for the BI recovery. The others were high, ranging from 15.4Δ for the BO recovery to 19.5Δ for the BO break. Fusional vergence ranges determined by prism bars out of the phoropter cannot be used interchangeably with those determined by phoropter rotary prisms for the purpose of follow-up on individual patients or for the purpose of comparison with norms. Copyright © 2010 American Optometric Association. Published by Elsevier Inc. All rights reserved.

Collisionless Boltzmann equation approach for the study of stellar discs within barred galaxies

NASA Astrophysics Data System (ADS)

Bienaymé, Olivier

2018-04-01

We have studied the kinematics of stellar disc populations within the solar neighbourhood in order to find the imprints of the Galactic bar. We carried out the analysis by developing a numerical resolution of the 2D2V (two-dimensional in the physical space, 2D, and two-dimensional in the velocity motion, 2V) collisionless Boltzmann equation and modelling the stellar motions within the plane of the Galaxy within the solar neighbourhood. We recover similar results to those obtained by other authors using N-body simulations, but we are also able to numerically identify faint structures thanks to the cancelling of the Poisson noise. We find that the ratio of the bar pattern speed to the local circular frequency is in the range ΩB/Ω = 1.77 to 1.91. If the Galactic bar angle orientation is within the range from 24 to 45 degrees, the bar pattern speed is between 46 and 49 km s-1 kpc-1.

MERIDIONAL TILT OF THE STELLAR VELOCITY ELLIPSOID DURING BAR BUCKLING INSTABILITY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saha, Kanak; Pfenniger, Daniel; Taam, Ronald E., E-mail: saha@mpe.mpg.de

2013-02-20

The structure and evolution of the stellar velocity ellipsoid play an important role in shaping galaxies undergoing bar-driven secular evolution and the eventual formation of a boxy/peanut bulge such as is present in the Milky Way. Using collisionless N-body simulations, we show that during the formation of such a boxy/peanut bulge, the meridional shear stress of stars, which can be measured by the meridional tilt of the velocity ellipsoid, reaches a characteristic peak in its time evolution. It is shown that the onset of a bar buckling instability is closely connected to the maximum meridional tilt of the stellar velocitymore » ellipsoid. Our findings bring a new insight to this complex gravitational instability of the bar which complements the buckling instability studies based on orbital models. We briefly discuss the observed diagnostics of the stellar velocity ellipsoid during such a phenomenon.« less

Novel combined stir bar sorptive extraction coupled with ultrasonic assisted extraction for the determination of brominated flame retardants in environmental samples using high performance liquid chromatography.

PubMed

Yu, Chunhe; Hu, Bin

2007-08-10

A combined stir bar coated with poly (dimethysiloxane)-beta-cyclodextrin (PDMS-beta-CD) on single side has been prepared for the first time by sol-gel method and was coupled with ultrasonic assisted extraction (UAE) for the determination of some brominated flame-retardant compounds (BFRs) in soil and dust samples by high performance liquid chromatography (HPLC). Four different kinds of coatings including PDMS-beta-CD, PDMS, carbowax (CW)-PDMS-poly (vinyl alcohol) (PVA) and PDMS-PVA were evaluated for stir bar sorptive extraction of BFRs by orthogonal experiment design. The experimental results reveal that the PDMS-beta-CD combined stir bar exhibited the best extraction efficiency for the target analytes. The reproducibility for the preparation of PDMS-beta-CD combined stir bar ranged from 1.3% to 15.7% in one batch, and 7.2% to 15.1% among batches. Extraction time, desorption solvent, concentration of methanol and NaCl in the matrix, pH, temperature and stirring speed were optimized. The combined stir bar can avoid direct friction of the coating with the bottom of the vessel, and could be used for more than 100 times. Linearity (>0.993), repeatability (<10.5%), reproducibility (<16.5%), recovery (56-118%) and detection limits (2.9-4.2 microg L(-1)) were proper to determine the seven BFRs. The developed method was applied to the determination of BFRs in soil and dust with satisfactory results.

The N-terminal domain of the thermo-regulated surface protein PrpA of Enterococcus faecium binds to fibrinogen, fibronectin and platelets

PubMed Central

Guzmán Prieto, Ana M.; Urbanus, Rolf T.; Zhang, Xinglin; Bierschenk, Damien; Koekman, C. Arnold; van Luit-Asbroek, Miranda; Ouwerkerk, Janneke P.; Pape, Marieke; Paganelli, Fernanda L.; Wobser, Dominique; Huebner, Johannes; Hendrickx, Antoni P. A.; Bonten, Marc J. M.; Willems, Rob J. L.; van Schaik, Willem

2015-01-01

Enterococcus faecium is a commensal of the mammalian gastrointestinal tract, but is also found in non-enteric environments where it can grow between 10 °C and 45 °C. E. faecium has recently emerged as a multi-drug resistant nosocomial pathogen. We hypothesized that genes involved in the colonization and infection of mammals exhibit temperature-regulated expression control and we therefore performed a transcriptome analysis of the clinical isolate E. faecium E1162, during mid-exponential growth at 25 °C and 37 °C. One of the genes that exhibited differential expression between 25 °C and 37 °C, was predicted to encode a peptidoglycan-anchored surface protein. The N-terminal domain of this protein is unique to E. faecium and closely related enterococci, while the C-terminal domain is homologous to the Streptococcus agalactiae surface protein BibA. This region of the protein contains proline-rich repeats, leading us to name the protein PrpA for proline-rich protein A. We found that PrpA is a surface-exposed protein which is most abundant during exponential growth at 37 °C in E. faecium E1162. The heterologously expressed and purified N-terminal domain of PrpA was able to bind to the extracellular matrix proteins fibrinogen and fibronectin. In addition, the N-terminal domain of PrpA interacted with both non-activated and activated platelets. PMID:26675410

The N-terminal domain of the thermo-regulated surface protein PrpA of Enterococcus faecium binds to fibrinogen, fibronectin and platelets.

PubMed

Guzmán Prieto, Ana M; Urbanus, Rolf T; Zhang, Xinglin; Bierschenk, Damien; Koekman, C Arnold; van Luit-Asbroek, Miranda; Ouwerkerk, Janneke P; Pape, Marieke; Paganelli, Fernanda L; Wobser, Dominique; Huebner, Johannes; Hendrickx, Antoni P A; Bonten, Marc J M; Willems, Rob J L; van Schaik, Willem

2015-12-17

Enterococcus faecium is a commensal of the mammalian gastrointestinal tract, but is also found in non-enteric environments where it can grow between 10 °C and 45 °C. E. faecium has recently emerged as a multi-drug resistant nosocomial pathogen. We hypothesized that genes involved in the colonization and infection of mammals exhibit temperature-regulated expression control and we therefore performed a transcriptome analysis of the clinical isolate E. faecium E1162, during mid-exponential growth at 25 °C and 37 °C. One of the genes that exhibited differential expression between 25 °C and 37 °C, was predicted to encode a peptidoglycan-anchored surface protein. The N-terminal domain of this protein is unique to E. faecium and closely related enterococci, while the C-terminal domain is homologous to the Streptococcus agalactiae surface protein BibA. This region of the protein contains proline-rich repeats, leading us to name the protein PrpA for proline-rich protein A. We found that PrpA is a surface-exposed protein which is most abundant during exponential growth at 37 °C in E. faecium E1162. The heterologously expressed and purified N-terminal domain of PrpA was able to bind to the extracellular matrix proteins fibrinogen and fibronectin. In addition, the N-terminal domain of PrpA interacted with both non-activated and activated platelets.

High-energy pp and pp-bar forward elastic scattering and total cross sections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Block, M.M.; Cahn, R.N.

1985-04-01

The present status of elastic pp and pp-bar scattering in the high-energy domain is reviewed, with emphasis on the forward and near-forward regions. The experimental techniques for measuring sigma/sub tot/, rho, and B are discussed, emphasizing the importance of the region in which the nuclear and Coulomb scattering interfere. The impact-parameter representation is exploited to give simple didactic demonstrations of important rigorous theorems based on analyticity, and to illuminate the significance of the slope parameter B and the curvature parameter C. Models of elastic scattering are discussed, and a criterion for the onset of ''asymptopia'' is given. A critique ofmore » dispersion relations is presented. Simple analytic functions are used to fit simultaneously the real and imaginary parts of forward scattering amplitudes for both pp and pp-bar, obtained from experimental data for sigma/sub tot/ and rho. It is found that a good fit can be obtained using only five parameters (with a cross section rising as ln/sup 2/s), over the energy range 5 < ..sqrt..s < 62 GeV. The possibilities that (a) the cross section rises only as lns, (b) the cross section rises only locally as ln/sup 2/s, and eventually goes to a constant value, and (c) the cross-section difference between pp and pp-bar does not vanish as s..-->..infinity are examined critically. The nuclear slope parameters B are also fitted in a model-independent fashion. Examination of the fits reveals a new regularity of the pp-bar and the pp systems.« less

Comparing the physiological and perceptual responses of construction workers (bar benders and bar fixers) in a hot environment.

PubMed

Wong, Del Pui-Lam; Chung, Joanne Wai-Yee; Chan, Albert Ping-Chuen; Wong, Francis Kwan-Wah; Yi, Wen

2014-11-01

This study aimed to (1) quantify the respective physical workloads of bar bending and fixing; and (2) compare the physiological and perceptual responses between bar benders and bar fixers. Field studies were conducted during the summer in Hong Kong from July 2011 to August 2011 over six construction sites. Synchronized physiological, perceptual, and environmental parameters were measured from construction rebar workers. The average duration of the 39 field measurements was 151.1 ± 22.4 min under hot environment (WBGT = 31.4 ± 2.2 °C), during which physiological, perceptual and environmental parameters were synchronized. Energy expenditure of overall rebar work, bar bending, and bar fixing were 2.57, 2.26 and 2.67 Kcal/min (179, 158 and 186 W), respectively. Bar fixing induced significantly higher physiological responses in heart rate (113.6 vs. 102.3 beat/min, p < 0.05), oxygen consumption (9.53 vs. 7.14 ml/min/kg, p < 0.05), and energy expenditure (2.67 vs. 2.26 Kcal/min, p < 0.05) (186 vs. 158 W, p < 0.05) as compared to bar bending. Perceptual response was higher in bar fixing but such difference was not statistically significant. Findings of this study enable the calculation of daily energy expenditure of rebar work. Copyright © 2014 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Annual Sediment Budgets for Newly Formed Point Bars on Powder River, Montana, USA

NASA Astrophysics Data System (ADS)

Moody, John; Meade, Robert

2013-04-01

Morphodynamic processes have been monitored for 37 years on Powder River, a large, unregulated meandering river that drains an area of about 35,000 km2 in northeastern Wyoming and southeastern Montana, USA. Cross-sectional surveys of the channel and adjacent floodplains and terraces have been measured nearly annually (30 out of 37 years) by the U.S. Geological Survey (USGS) at 24 locations along 90 kilometers of the river. This long-term data set has provided insights into the natural morphological and sedimentary processes; and most recently, into the annual sediment budgets for three point bars that were created when an extreme flood in 1978 cut new channels across the necks of two former meander bends and radically shifted the location of a third bend. Because our cross-sectional surveys are generally made only once a year (during the low-flow period, usually September-October), we record only the net change in thickness of the annual deposition and erosion because some areas on a point bar may be scoured and refilled during multiple floods in a year. Point-bar sediment budgets vary spatially as well as annually. The long-term average of the net annual sediment budgets during the post-1978 years (n=26 surveys) indicates that the average annual increment of new sediment deposited on the three point bars has been three to four times the average annual increment of old sediment eroded from the point bars. This annual deposition-to-erosion ratio has varied at one point bar from a minimum of 0.14 (1986) to maximum of 275 (1995). At the other two point-bar sites the ratio ranged from 0.18 (1991) to 265 (2008) and from 0.023 (1980) to 479 (1987). The lack of correlation from year to year or from one point bar to the next suggests the importance of differences in the planimetric configurations and hydraulic histories of each point bar in the evolutionary process. All the deposited sediment we measured during an annual survey represents the same sediment year class

The e{sup +}e{sup -}{yields}J/{psi}DD-bar, J/{psi}DD-bar* reactions with dynamically generated resonances

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gamermann, D.; Oset, E.

2008-08-31

In two recent reactions by Belle producing DD-bar and DD-bar* meson pairs, peaks above threshold have been measured in the differential cross sections, possibly indicating new resonances in these channels. We want to study such reactions from the point of view that the D meson pairs are produced from already known or predicted resonances below threshold. Our study shows that the peak in the DD-bar* production is not likely to be caused by the X(3872) resonance, but the peak seen in DD-bar invariant mass can be well described if the DD-bar pair comes from the already predicted scalar X(3700) resonance.

Barred Ring Galaxy NGC 1291

NASA Image and Video Library

2005-05-05

This ultraviolet image left and visual image right from NASA Galaxy Evolution Explorer is of the barred ring galaxy NGC 1291. The VIS image is dominated by the inner disk and bar. The UV image is dominated by the low surface brightness outer arms.

Characterizing bars in low surface brightness disc galaxies

NASA Astrophysics Data System (ADS)

Peters, Wesley; Kuzio de Naray, Rachel

2018-05-01

In this paper, we use B-band, I-band, and 3.6 μm azimuthal light profiles of four low surface brightness galaxies (LSBs; UGC 628, F568-1, F568-3, F563-V2) to characterize three bar parameters: length, strength, and corotation radius. We employ three techniques to measure the radius of the bars, including a new method using the azimuthal light profiles. We find comparable bar radii between the I-band and 3.6 μm for all four galaxies when using our azimuthal light profile method, and that our bar lengths are comparable to those in high surface brightness galaxies (HSBs). In addition, we find the bar strengths for our galaxies to be smaller than those for HSBs. Finally, we use Fourier transforms of the B-band, I-band, and 3.6 μm images to characterize the bars as either `fast' or `slow' by measuring the corotation radius via phase profiles. When using the B- and I-band phase crossings, we find three of our galaxies have faster than expected relative bar pattern speeds for galaxies expected to be embedded in centrally dense cold dark matter haloes. When using the B-band and 3.6 μm phase crossings, we find more ambiguous results, although the relative bar pattern speeds are still faster than expected. Since we find a very slow bar in F563-V2, we are confident that we are able to differentiate between fast and slow bars. Finally, we find no relation between bar strength and relative bar pattern speed when comparing our LSBs to HSBs.

The carcinoembryonic antigen IgV-like N domain plays a critical role in the implantation of metastatic tumor cells.

PubMed

Abdul-Wahid, Aws; Huang, Eric H-B; Cydzik, Marzena; Bolewska-Pedyczak, Eleonora; Gariépy, Jean

2014-03-01

The human carcinoembryonic antigen (CEA) is a cell adhesion molecule involved in both homotypic and heterotypic interactions. The aberrant overexpression of CEA on adenocarcinoma cells correlates with their increased metastatic potential. Yet, the mechanism(s) by which its adhesive properties can lead to the implantation of circulating tumor cells and expansion of metastatic foci remains to be established. In this study, we demonstrate that the IgV-like N terminal domain of CEA directly participates in the implantation of cancer cells through its homotypic and heterotypic binding properties. Specifically, we determined that the recombinant N terminal domain of CEA directly binds to fibronectin (Fn) with a dissociation constant in the nanomolar range (K(D) 16 ± 3 nM) and interacts with itself (K(D) 100 ± 17 nM) and more tightly to the IgC-like A(3) domain (K(D) 18 ± 3 nM). Disruption of these molecular associations through the addition of antibodies specific to the CEA N or A(3)B(3) domains, or by adding soluble recombinant forms of the CEA N, A(3) or A(3)B(3) domains or a peptide corresponding to residues 108-115 of CEA resulted in the inhibition of CEA-mediated intercellular aggregation and adherence events in vitro. Finally, pretreating CEA-expressing murine colonic carcinoma cells (MC38.CEA) with rCEA N, A3 or A(3)B(3) modules blocked their implantation and the establishment of tumor foci in vivo. Together, these results suggest a new mechanistic insight into how the CEA IgV-like N domain participates in cellular events that can have a macroscopic impact in terms of cancer progression and metastasis. Copyright © 2013 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Application of modified stir bar with nickel:zinc sulphide nanoparticles loaded on activated carbon as a sorbent for preconcentration of losartan and valsartan and their determination by high performance liquid chromatography.

PubMed

Pebdani, Arezou Amiri; Dadfarnia, Shayesteh; Shabani, Ali Mohammad Haji; Khodadoust, Saeid; Haghgoo, Soheila

2016-03-11

In this study, the stir bar was coated for the first time with the ​nicel:zins sulphide nanoparticles (Ni:ZnS NPs) loaded on activated carbon (AC) (Ni:ZnS-AC) as well as 1-ethyl-3-methylimidazolium hexafluorophosphate ionic liquid (IL) using sol gel technique and was used for stir bar sorptive extraction (SBSE) of losartan (LOS) and valsartan (VAL) as the model compounds. The extracted analytes were then quantified by high performance liquid chromatography (HPLC) equipped with an ultra violet detector. The best extraction performance for LOS and VAL was obtained through the optimization of the parameters affecting SBSE including pH of sample solution, ionic strength, extraction time, volume of desorption solvent, desorption time, and stirring speed. The fractional factorial design (FFD) was used to find the most important parameters, which were then optimized by the central composite design (CCD) and the desirability function (DF). Under the optimal experimental conditions, wide linear ranges of 0.4-50μgL(-1) and 0.5-50μgL(-1) and good RSDs (at level of 5μgL(-1) and n=6) of 4.4 and 4.9% were obtained for LOS and VAL, respectively. With the enrichment factors (EFs) of 188.6 and 184.8-fold, the limits of detection (LODs, S/N=3) of the developed method were found to be 0.12 and 0.15μgL(-1) for LOS and VAL, respectively. The developed method was successfully applied to the determination of LOS and VAL in urine and plasma matrices. Copyright © 2016 Elsevier B.V. All rights reserved.

Impact of a Structural Intervention to Address Alcohol Use Among Gay Bar Patrons in San Francisco: The PACE Study.

PubMed

Charlebois, Edwin D; Plenty, Albert H; Lin, Jessica; Ayala, Alicia; Hecht, Jennifer

2017-11-01

We evaluated the impact on alcohol intake and blood alcohol concentration (BAC) of a multi-level structural intervention to increase the availability of free water, coupled with messaging on pacing alcohol intake and normative feedback of blood alcohol concentration in a convenience sample of gay bars in San Francisco. Participants (n = 1,293) were recruited among exiting patrons of four gay bars (two intervention bars and two control bars). Participants were surveyed on alcohol intake and BAC was measured by breathalyzer. Prior to the intervention there were no significant differences in baseline alcohol measures between intervention and control bars. Post-intervention there were significant differences on objective and subjective measures of alcohol consumption: 30% of intervention bar participants had BAC% levels over the legal driving limit (0.08%) compared to 43% of control bar participants, p < 0.0001 and 78% of intervention bar participants were above the AUDIT-C cut-off for hazardous drinking compared to 87% in control bars, p < 0.001.