Modeling Methane Adsorption in Interpenetrating Porous Polymer Networks

Porous polymer networks (PPNs) are a class of porous materials of particular interest in a variety of energy-related applications because of their stability, high surface areas, and gas uptake capacities. Computationally derived structures for five recently synthesized PPN frameworks, PPN-2, -3, -4, -5, and -6, were generated for various topologies, optimized using semiempirical electronic structure methods, and evaluated using classical grand-canonical Monte Carlo simulations. We show that a key factor in modeling the methane uptake performance of these materials is whether, and how, these material frameworks interpenetrate and demonstrate a computational approach for predicting the presence, degree, and nature of interpenetration in PPNs that enables the reproduction of experimental adsorption data. © 2013 American Chemical Society

In-street wind direction variability in the vicinity of a busy intersection in central London

We present results from fast-response wind measurements within and above a busy intersection between two street canyons (Marylebone Road and Gloucester Place) in Westminster, London taken as part of the DAPPLE (Dispersion of Air Pollution and Penetration into the Local Environment; www.dapple.org.uk) 2007 field campaign. The data reported here were collected using ultrasonic anemometers on the roof-top of a building adjacent to the intersection and at two heights on a pair of lamp-posts on opposite sides of the intersection. Site characteristics, data analysis and the variation of intersection flow with the above-roof wind direction (θref) are discussed. Evidence of both flow channelling and recirculation was identified within the canyon, only a few metres from the intersection for along-street and across-street roof-top winds respectively. Results also indicate that for oblique rooftop flows, the intersection flow is a complex combination of bifurcated channelled flows, recirculation and corner vortices. Asymmetries in local building geometry around the intersection and small changes in the background wind direction (changes in 15-min mean θref of 5–10 degrees) were also observed to have profound influences on the behaviour of intersection flow patterns. Consequently, short time-scale variability in the background flow direction can lead to highly scattered in-street mean flow angles masking the true multi-modal features of the flow and thus further complicating modelling challenges

Sublinear Algorithms for Approximating String Compressibility

We raise the question of approximating the compressibility of a string with respect to a fixed compression scheme, in sublinear time. We study this question in detail for two popular lossless compression schemes: run-length encoding (RLE) and a variant of Lempel-Ziv (LZ77), and present sublinear algorithms for approximating compressibility with respect to both schemes. We also give several lower bounds that show that our algorithms for both schemes cannot be improved significantly. Our investigation of LZ77 yields results whose interest goes beyond the initial questions we set out to study. In particular, we prove combinatorial structural lemmas that relate the compressibility of a string with respect to LZ77 to the number of distinct short substrings contained in it (its ℓth subword complexity , for small ℓ). In addition, we show that approximating the compressibility with respect to LZ77 is related to approximating the support size of a distribution.National Science Foundation (U.S.) (Award CCF-1065125)National Science Foundation (U.S.) (Award CCF-0728645)Marie Curie International Reintegration Grant PIRG03-GA-2008-231077Israel Science Foundation (Grant 1147/09)Israel Science Foundation (Grant 1675/09

Incidence of multiple Herpesvirus infection in HIV seropositive patients, a big concern for Eastern Indian scenario

<p>Abstract</p> <p>Background</p> <p>Human immunodeficiency virus (HIV) infection is associated with an increased risk for human <it>herpes viruses </it>(HHVs) and their related diseases and they frequently cause disease deterioration and therapeutic failures. Methods for limiting the transmission of HHVs require a better understanding of the incidence and infectivity of oral HHVs in HIV-infected patients. This study was designed to determine the seroprevalence of human herpes viruses (CMV, HSV 2, EBV-1, VZV) antibodies and to evaluate their association with age, sex as well as other demographic and behavioral factors.</p> <p>Results</p> <p>A study of 200 HIV positive patients from Eastern India attending the Calcutta Medical College Hospital, Kolkata, West Bengal, Apex Clinic, Calcutta Medical College Hospital and ART Center, School of Tropical Medicine, Kolkata, West Bengal was done. Serum samples were screened for antibodies to the respective viruses using the indirect ELISA in triplicates.</p> <p><it>CytoMegalo virus </it>(CMV), <it>Herpes Simplex virus </it>type 2 (HSV-2), <it>Varicella Zoster virus </it>(VZV), and <it>Epstein Barr virus </it>(EBV-1) were detected in 49%, 47%, 32.5%, and 26% respectively.</p> <p>Conclusion</p> <p>This study has contributed baseline data and provided insights in viral OI and HIV co-infection in Eastern India. This would undoubtedly serve as a basis for further studies on this topic.</p

A-type and B-type Epstein-Barr virus differ in their ability to spontaneously enter the lytic cycle

In this study replication of A-type and B-type Epstein-Barr virus (EBV) strains has been assessed. A-type and B-type lymphoblastoid cell lines (LCLs) were established by infecting B lymphocytes, isolated from five EBV-seropositive donors, with different A-type and B-type virus isolates. The presence of viral capsid antigens (VCA) in these LCLs was determined by immunofluoresence assay and by immunoblotting, All of the B-type EBV strains were capable of spontaneously generating virus regardless of the origin of the donor cells. In contrast the A-type strains, other than strain IARC-BL36, did not readily produce VCA in any of the different donor lymphocytes used. This study demonstrates another biological difference between the two virus types: their ability to spontaneously enter the lyric cycle

Human Sin1 contains Ras-binding and pleckstrin homology domains and suppresses Ras signaling

Human Sin1 (SAPK-interacting protein 1) is a member of a conserved family of orthologous proteins that have an essential role in signal transduction in yeast and Dictyostelium. This study demonstrates that most Sin I orthologues contain both a Raf-like Ras-binding domain (RBD) and a pleckstrin homology (PH) domain. These domains are functional in the human Sin1 protein, with the PH domain involved in lipid and membrane binding by SinI, and the RBD able to bind activated H-and K-Ras. Sin1 and Ras co-immunoprecipitated and co-localised, showing that these proteins associate with each other in vivo. Overexpression of Sin I inhibited the activation of ERK, Akt and JNK signalling pathways by Ras. In contrast, siRNA knockdown of endogenous Sin1 protein expression in HEK293 cells enhanced the activation of ERK1/2 by Ras. These data suggest that SinI is a mammalian Ras-inhibitor. (c) 2007 Elsevier Inc. All rights reserved