54 research outputs found

    Structural and Physico-Chemical Interpretation (SPCI) of QSAR Models and Its Comparison with Matched Molecular Pair Analysis

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    © 2016 American Chemical Society.This paper describes the Structural and Physico-Chemical Interpretation (SPCI) approach, which is an extension of a recently reported method for interpretation of quantitative structure-activity relationship (QSAR) models. This approach can efficiently be used to reveal structural motifs and the major physicochemical factors affecting the investigated properties. Its efficacy was demonstrated both on the classical Free-Wilson data set and on several data sets with different end points (permeability of the blood-brain barrier, fibrinogen receptor antagonists, acute oral toxicity). Structure-activity patterns extracted from QSAR models with SPCI were in good correspondence with experimentally observed relationships and molecular docking, regardless of the machine learning method used. Comparison of SPCI with the matched molecular pair (MMP) method clearly shows an advantage of our approach over MMP, especially for small or structurally diverse data sets. The developed approach has been implemented in the SPCI software tool with a graphical user interface, which is publicly available at http://qsar4u.com/pages/sirms-qsar.php

    Spin alignment of K(892)±K^*(892)^\pm mesons produced in neutron-carbon interactions

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    A new precise measurements of spin density matrix element ρ00\rho_{00} of K(892)±K^*(892)^{\pm} mesons produced inclusively in neutron-carbon interactions at \~60 GeV have been carried out in the EXCHARM experiment at the Serpukhov accelerator. The values of ρ00\rho_{00} obtained in the transversity frame are 0.424±0.011(stat)±0.018(sys)0.424\pm0.011(stat)\pm0.018(sys) for K(892)+K^*(892)^+ and 0.393±0.025(stat)±0.018(sys)0.393\pm0.025(stat)\pm0.018(sys) for K(892)K^*(892)^-. Significant PTP_T dependence of ρ00\rho_{00} has been observed in K(892)+K^*(892)^+ production.Comment: 8 pages, LaTeX, 3 eps figure

    Hydrogen peroxide bleaching of cellulose pulps obtained from brewer’s spent grain

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    Brewer’s spent grain (BSG) was evaluated for bleached pulp production. Two cellulose pulps with different chemical compositionswere produced by soda pulping: one from the original raw material and the other from material pretreated by dilute acid. Both of them were bleached by a totally chlorine-free sequence performed in three stages, using 5% hydrogen peroxide in the two initial, and a 0.25 NNaOHsolution in the last one. Chemical composition, kappa number, viscosity, brightness and yield of bleached and unbleached pulps were evaluated. The high hemicellulose (28.4% w/w) and extractives (5.8% w/w) contents in original BSG affected the pulping and bleaching processes.However, soda pulping of acid pretreated BSG gave a celluloserich pulp (90.4% w/w) with low hemicellulose and extractives contents (7.9% w/w and <3.4% w/w, respectively), which was easily bleached achieving a kappa number of 11.21, viscosity of 3.12 cp, brightness of 71.3%, cellulose content of 95.7% w/w, and residual lignin of 3.4% w/w. Alkaline and oxidative delignification of acid pretreated BSG was found as an attractive approach for producing high-purity, chlorine-free cellulose pulp.FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo), Brazil.CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico).Capes (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior)

    Ancient Ancestry of KFDV and AHFV Revealed by Complete Genome Analyses of Viruses Isolated from Ticks and Mammalian Hosts

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    Alkhurma hemorrhagic fever (AHF) and Kyasanur Forest disease (KFD) viruses both cause serious and sometimes fatal human disease in their respective ranges, Saudi Arabia and India. AHFV was first identified in the mid-1990s and due to its strong genetic similarity to KFDV it has since been considered the result of a recent introduction of KFDV into Saudi Arabia. To gain a better understanding of the evolutionary history of AHFV and KFDV, we sequenced the full-length genomes of 3 KFDV and 16 AHFV. Sequence analyses show a greater genetic diversity within AHFV than previously thought, particularly within the tick population. The phylogeny constructed with these 19 full-length sequences and two AHFV sequences from GenBank indicates AHFV diverged from KFDV almost 700 years ago. Given the presence of competent tick vectors in the regions between and surrounding Saudi Arabia and India and the recent identification of AHFV in Egypt, these results suggest a broader geographic range of AHFV and KFDV, and raise the possibility of other AHFV/KFDV–like viruses circulating in these regions

    The Phylogenetics and Ecology of the Orthopoxviruses Endemic to North America

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    The data presented herein support the North American orthopoxviruses (NA OPXV) in a sister relationship to all other currently described Orthopoxvirus (OPXV) species. This phylogenetic analysis reaffirms the identification of the NA OPXV as close relatives of “Old World” (Eurasian and African) OPXV and presents high support for deeper nodes within the Chordopoxvirinae family. The natural reservoir host(s) for many of the described OPXV species remains unknown although a clear virus-host association exists between the genus OPXV and several mammalian taxa. The hypothesized host associations and the deep divergence of the OPXV/NA OPXV clades depicted in this study may reflect the divergence patterns of the mammalian faunas of the Old and New World and reflect a more ancient presence of OPXV on what are now the American continents. Genes from the central region of the poxvirus genome are generally more conserved than genes from either end of the linear genome due to functional constraints imposed on viral replication abilities. The relatively slower evolution of these genes may more accurately reflect the deeper history among the poxvirus group, allowing for robust placement of the NA OPXV within Chordopoxvirinae. Sequence data for nine genes were compiled from three NA OPXV strains plus an additional 50 genomes collected from Genbank. The current, gene sequence based phylogenetic analysis reaffirms the identification of the NA OPXV as the nearest relatives of “Old World” OPXV and presents high support for deeper nodes within the Chordopoxvirinae family. Additionally, the substantial genetic distances that separate the currently described NA OPXV species indicate that it is likely that many more undescribed OPXV/NA OPXV species may be circulating among wild animals in North America

    Detection of π+π\pi^+\pi^-atoms with the DIRAC spectrometer at CERN

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    The goal of the DIRAC experiment at CERN is to measure with high precision the lifetime of the π+π\pi^+\pi^- atom (A2πA_{2\pi}), which is of order 3×10153\times10^{-15} s, and thus to determine the s-wave ππ\pi\pi-scattering lengths difference a0a2|a_{0}-a_{2}|. A2πA_{2\pi} atoms are detected through the characteristic features of π+π\pi^+\pi^- pairs from the atom break-up (ionization) in the target. We report on a first high statistics atomic data sample obtained from p Ni interactions at 24 GeV/cc proton momentum and present the methods to separate the signal from the background.Comment: 19 pages, 12 figures, 1 tabl

    Genetic Detection and Characterization of Lujo Virus, a New Hemorrhagic Fever–Associated Arenavirus from Southern Africa

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    Lujo virus (LUJV), a new member of the family Arenaviridae and the first hemorrhagic fever–associated arenavirus from the Old World discovered in three decades, was isolated in South Africa during an outbreak of human disease characterized by nosocomial transmission and an unprecedented high case fatality rate of 80% (4/5 cases). Unbiased pyrosequencing of RNA extracts from serum and tissues of outbreak victims enabled identification and detailed phylogenetic characterization within 72 hours of sample receipt. Full genome analyses of LUJV showed it to be unique and branching off the ancestral node of the Old World arenaviruses. The virus G1 glycoprotein sequence was highly diverse and almost equidistant from that of other Old World and New World arenaviruses, consistent with a potential distinctive receptor tropism. LUJV is a novel, genetically distinct, highly pathogenic arenavirus

    Carbonization of some fast-growing species in Sudan

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    Four wood species, indigenous Acacia seyal (talh) and exotic fast-growing Conocarpus lancifolius (damas), Eucalyptus microtheca (kafur) and Prosopis chilensis (mesquite) grown in Sudan, were assessed and compared as raw materials for charcoal making. The effects of production method (traditional earth mound and improved metal kiln) and the physical and chemical properties of the wood and bark on the yield and quality of charcoal produced were assessed. Regression analyses of wood properties and heat value data indicated high negative correlations of the wood heat value with holocellulose and ash, and high positive correlations with wood density, lignin, and alcohol-benzene and hot-water solubles. Carbonization with the Tropical Products Institute metal kiln produced higher yields (33%) than the traditional earth mound (27%), although the difference in energy transformation yields was found to be insignificant both between appliances and species. Charcoal produced by the earth mound had a slightly higher density and was more resistant to shatter, but no significant differences were recorded with respect to the water boiling test or the gross heat value. The exotic species studied gave equal or better charcoal, in terms of yield and quality, compared with the traditionally preferred talh.
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