5,562 research outputs found
Sixteen-fermion and related terms in M-theory on T**2
Certain one-loop processes in eleven-dimensional supergravity compactified on
T**2 determine exact, non-perturbative, terms in the effective action of type
II string theories compactified on a circle. One example is the modular
invariant U(1)-violating interaction of sixteen complex spin-1/2 fermions of
ten-dimensional type IIB theory. This term, together with the (curvature)**4
term, and many other terms of the same dimension are all explicitly related by
supersymmetry.Comment: 14 Pages, Latex, no figures, Minor changes, version to appear in PL
Light-cone Quantum Mechanics of the Eleven-dimensional Superparticle
The linearized interactions of eleven-dimensional supergravity are obtained
in a manifestly supersymmetric light-cone gauge formalism. These vertices are
used to calculate certain one-loop processes involving external gravitini,
antisymmetric three-form potentials and gravitons, thereby determining some
protected terms in the effective action of M-theory compactified on a
two-torus.Comment: 31 pages, harvmac (b); A minor TeX error correcte
An Efficient Modified "Walk On Spheres" Algorithm for the Linearized Poisson-Boltzmann Equation
A discrete random walk method on grids was proposed and used to solve the
linearized Poisson-Boltzmann equation (LPBE) \cite{Rammile}. Here, we present a
new and efficient grid-free random walk method. Based on a modified `` Walk On
Spheres" (WOS) algorithm \cite{Elepov-Mihailov1973} for the LPBE, this Monte
Carlo algorithm uses a survival probability distribution function for the
random walker in a continuous and free diffusion region. The new simulation
method is illustrated by computing four analytically solvable problems. In all
cases, excellent agreement is observed.Comment: 12 pages, 5 figure
BindingDB in 2015: A public database for medicinal chemistry, computational chemistry and systems pharmacology.
BindingDB, www.bindingdb.org, is a publicly accessible database of experimental protein-small molecule interaction data. Its collection of over a million data entries derives primarily from scientific articles and, increasingly, US patents. BindingDB provides many ways to browse and search for data of interest, including an advanced search tool, which can cross searches of multiple query types, including text, chemical structure, protein sequence and numerical affinities. The PDB and PubMed provide links to data in BindingDB, and vice versa; and BindingDB provides links to pathway information, the ZINC catalog of available compounds, and other resources. The BindingDB website offers specialized tools that take advantage of its large data collection, including ones to generate hypotheses for the protein targets bound by a bioactive compound, and for the compounds bound by a new protein of known sequence; and virtual compound screening by maximal chemical similarity, binary kernel discrimination, and support vector machine methods. Specialized data sets are also available, such as binding data for hundreds of congeneric series of ligands, drawn from BindingDB and organized for use in validating drug design methods. BindingDB offers several forms of programmatic access, and comes with extensive background material and documentation. Here, we provide the first update of BindingDB since 2007, focusing on new and unique features and highlighting directions of importance to the field as a whole
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Biotin Supplementation Ameliorates Murine Colitis by Preventing NF-κB Activation.
Background & aimsBiotin is a water-soluble vitamin that is indispensable for human health. Biotin deficiency can cause failure-to-thrive, immunodeficiency, alopecia, dermatitis, and conjunctivitis. We previously reported that biotin deficiency also can lead to severe colitis in mice, which is completely reversed with supplementation. Our aim in this study was to determine if high-dose biotin supplementation can provide a therapeutic benefit in a preclinical model for inflammatory bowel disease (IBD) and to identify the molecular mechanism by which this occurs.MethodsMice were challenged with dextran sodium sulfate to induce colitis and were treated with 1 mmol/L biotin to induce or maintain remission. Clinical response was monitored by the Disease Activity Index and fecal calprotectin levels. The colon tissue was investigated for histology, length, as well as expression of inflammatory cytokines (interleukin 6, tumor necrosis factor-α, interleukin 1β), intestinal permeability, tight junctions (zonula occludens-1 and claudin-2), and the transcription factor nuclear factor-κB (NF-κB).ResultsBiotin therapy led to delayed onset and severity of colitis as well as accelerated healing. There was improvement in the Disease Activity Index, fecal calprotectin levels, colon length, and histology. In addition, biotin-treated mice had reduced expression of inflammatory cytokines, reduced intestinal permeability, and reduced activation of NF-κB.ConclusionsOral supplementation with biotin provides benefit for maintenance and induction of remission in the dextran sodium sulfate preclinical model for IBD. Biotin does this by reducing the activation of NF-κB, which prevents the production of inflammatory cytokines and helps maintain the integrity of the intestinal barrier. Clinically, the NF-κB pathway is important in the development of IBD and this finding suggests that biotin may have therapeutic potential for patients with IBD
Improved Combinatorial Group Testing Algorithms for Real-World Problem Sizes
We study practically efficient methods for performing combinatorial group
testing. We present efficient non-adaptive and two-stage combinatorial group
testing algorithms, which identify the at most d items out of a given set of n
items that are defective, using fewer tests for all practical set sizes. For
example, our two-stage algorithm matches the information theoretic lower bound
for the number of tests in a combinatorial group testing regimen.Comment: 18 pages; an abbreviated version of this paper is to appear at the
9th Worksh. Algorithms and Data Structure
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