5,200 research outputs found

    (S)-(-)-1-Phenylethanaminium hexanoate

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    A binary mixture of (S)-(-)-1-phenylethanamine and hexanoic acid was allowed to react to form the title salt, C8H12N+·C6H11O2-. This crystal contains a 1:1 stoichiometric mixture of the acid- and amine-derived species and displays a chiral structure with N-H...O hydrogen-bonded chains propagating along the c-axis direction.This work was supported by the Department of Chemistry, the BP Institute and the Oppenheimer Trust

    Has there been a turning point in the numbers of AIDS and HIV antibody positive cases in Ireland?

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    Significant developments in the prevention and treatment of human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS) have taken place in recent years. Changes in the size of the HIV and AIDS epidemic need to be monitored to assess these developments and plan future services. This paper describes temporal trends in the incidence of HIV and AIDS in Ireland, describing separately the major risk groups, and to explore possible associations between these trends with developments in care. The annual numbers of HIV and AIDS in Ireland were analysed to determine whether there has been a turning point in incidence. There has been an overall decrease in the numbers of AIDS cases since 1993, with both homosexual and intravenous drug users (IDU) risk groups exhibiting a decrease. For HIV antibody positive individuals, overall numbers have remained constant. However, there has been an upward trend in the heterosexual risk group and a downward trend in the IDU risk group. Thus both AIDS and HIV numbers exhibit turning points. Declines in HIV and AIDS incidence in the homosexual and IDU risk groups are indirectly attributable to health safety and treatment programmes. The increase in HIV antibody positive cases among heterosexuals may reflect a relapse in safe sex behaviour

    Benzylammonium hexanoate

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    A binary mixture of benzylamine and hexanoic acid has been reacted to form the title salt, C7H10N+·C6H11O2-. This crystal has a 1:1 stoichiometry of acid- and amine-derived species which contrasts with other related species which can have a number of other integer ratios of acid and amine components. The diffraction data indicate complete transfer of a proton from the acid to the amine to give the salt, comprising a cation and anion combination, with the formation of three hydrogen bonds around each ammonium group. This contrasts with other related species.This work was supported by the Department of Chemistry, the BP Institute and the Oppenheimer Trust

    Complex rift geometries resulting from inheritance of pre-existing structures: Insights and regional implications from the Barmer Basin rift

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    Structural studies of the Barmer Basin in Rajasthan, northwest India, demonstrate the important effect that pre-existing faults can have on the geometries of evolving fault systems at both the outcrop and basin-scale. Outcrop exposures on opposing rift margins reveal two distinct, non-coaxial extensional events. On the eastern rift margin northwest–southeast extension was accommodated on southwest- and west-striking faults that form a complex, zig-zag fault network. On the western rift margin northeast–southwest extension was accommodated on northwest-striking faults that form classical extensional geometries. Combining these outcrop studies with subsurface interpretations demonstrates that northwest–southeast extension preceded northeast–southwest extension. Structures active during the early, previously unrecognised extensional event were variably incorporated into the evolving fault systems during the second. In the study area, an inherited rift-oblique fault transferred extension from the rift margin to a mid-rift fault, rather than linking rift margin fault systems directly. The resultant rift margin accommodation structure has important implications for early sediment routing and depocentre evolution, as well as wider reaching implications for the evolution of the rift basin and West Indian Rift System. The discovery of early rifting in the Barmer Basin supports that extension along the West Indian Rift System was long-lived, multi-event, and likely resulted from far-field plate reorganisations

    The International Crop Information System manages geneological; phenotypic and genotypic data in a wheat breeding program

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    Lysyl hydroxylase 2b (LH2b) is known to increase pyridinoline cross-links, making collagen less susceptible to enzymatic degradation. Previously, we observed a relationship between LH2b and osteoarthritis-related fibrosis in murine knee joint. For this study, we investigate if transforming growth factor-beta (TGF-) and connective tissue growth factor (CTGF) regulate procollagen-lysine, 2-oxoglutarate 5-dioxygenase 2 (PLOD2) (gene encoding LH2b) and LH2b expression differently in osteoarthritic human synovial fibroblasts (hSF). Furthermore, we investigate via which TGF- route (Smad2/3P or Smad1/5/8P) LH2b is regulated, to explore options to inhibit LH2b during fibrosis. To answer these questions, fibroblasts were isolated from knee joints of osteoarthritis patients. The hSF were stimulated with TGF- with or without a kinase inhibitor of ALK4/5/7 (SB-505124) or ALK1/2/3/6 (dorsomorphin). TGF-, CTGF, constitutively active (ca)ALK1 and caALK5 were adenovirally overexpressed in hSF. The gene expression levels of PLOD1/2/3, CTGF and COL1A1 were analyzed with Q-PCR. LH2 protein levels were determined with western blot. As expected, TGF- induced PLOD2/LH2 expression in hSF, whereas CTGF did not. PLOD1 and PLOD3 were not affected by either TGF- or CTGF. SB-505124 prevented the induction of TGF--induced PLOD2, CTGF and COL1A1. Surprisingly, dorsomorphin completely blocked the induction of CTGF and COL1A1, whereas TGF--induced PLOD2 was only slightly reduced. Overexpression of caALK5 in osteoarthritic hSF significantly induced PLOD2/LH2 expression, whereas caALK1 had no effect. We showed, in osteoarthritic hSF, that TGF- induced PLOD2/LH2 via ALK5 Smad2/3P. This elevation of LH2b in osteoarthritic hSF makes LH2b an interesting target to interfere with osteoarthritis-related persistent fibrosis

    Effect of the solvent quadrupolarizability on the strength of the hydrogen bond: Theory vs data for the Gibbs energy and enthalpy of homo- and heteroassociation between carboxylic acids and water.

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    A cavity model of the effect of a solvent on thermodynamic parameters of dimerization of polar species in non-polar liquids has been developed and compared to experimental data. Bulk solution data have been collected for stearic acid in cyclohexane and in toluene to quantify the extent of self-association of the acid in terms of the dimer self-dissociation constant, Kd. Composition and temperature-dependent experimental data have been collected to determine Kd, the enthalpy of dissociation, and temperature-dependent infrared molar absorption coefficients. The interaction of stearic acid with small amounts of water present in non-aqueous solvents is also addressed and quantified with a hetero-dissociation (or dehydration) constant, Kh. Existing data for acetic acid are also considered. The model connects Kd and Kh to the vapor-phase association equilibria. Solute dipole-solvent quadrupole interactions are shown to have a major effect on Kd in quadrupolar liquids, such as toluene, benzene, and CS2. This work provides important background as a prelude to adsorption studies of these additives from non-aqueous solvents to solid surfaces with relevance to commercial fluids, such as oil-based corrosion inhibitors and friction modifiers. Moreover, the presented theory of the solvent effect on Kd is a first step to generalization of standard implicit solvent models in computational chemistry (such as the polarizable continuum model) to media of significant quadrupolar strength. This is expected to be particularly important for polar species dissolved in CO2 relevant for carbon capture and storage where appropriate models do not currently exist

    Neutron Reflectometry for Studying Corrosion and Corrosion Inhibition

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    Neutron reflectometry is an extremely powerful technique to monitor chemical and morphological changes at interfaces at the angstrom-level. Its ability to characterise metal, oxide and organic layers simultaneously or separately and in situ makes it an excellent tool for fundamental studies of corrosion and particularly adsorbed corrosion inhibitors. However, apart from a small body of key studies, it has yet to be fully exploited in this area. We present here an outline of the experimental method with particular focus on its application to the study of corrosive systems. This is illustrated with recent examples from the literature addressing corrosion, inhibition and related phenomena
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