89 research outputs found

    Expanding the scope of N → S acyl transfer in native peptide sequences

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    Understanding the factors that influence N → S acyl transfer in native peptide sequences, and discovery of new reagents that facilitate it, will be key to expanding its scope and applicability. Here, through a study of short model peptides in thioester formation and cyclisation reactions, we demonstrate that a wider variety of Xaa-Cys motifs than originally envisaged are capable of undergoing efficient N → S acyl transfer. We present data for the relative rates of thioester formation and cyclisation for a representative set of amino acids, and show how this expanded scope can be applied to the production of the natural protease inhibitor Sunflower Trypsin Inhibitor-1 (SFTI-1)

    Dirhenium carbonyl compounds bearing cis-1,2-bis(diphenylphosphino)ethylene and cis-1,2-bis(diphenylphosphino)ethylene oxide ligands

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    1289-1295Reaction of [Re2(CO)9(MeCN)] with cis-1,2-bis(diphenylphosphino)ethylene (cis-Ph2PCH=CHPPh2) in boiling benzene (80 °C) afforded two compounds, ax-[Re2(CO)9(κ1-cis-Ph2PCH=CHPPh2)] (1) and ax-[Re2(CO)9{κ1-cis- Ph2PCH=CHPh2P(O)}] (2) where the ligand is axially coordinated in a κ1 monodentate fashion through phosphorus. The close-bridged compound eq-[Re2(CO)8(μ-κ2-cis-Ph2PCH=CHPPh2)] (3) is obtained from a similar reaction of the same ligand with [Re2(CO)8(NCMe)2] in refluxing benzene. In this case the diphosphine is equatorially coordinated to two Re atoms in a symmetrical bridging fashion. Compounds 1−3 have been characterized by IR, 1H NMR, 31P{1H} NMR spectroscopy and single crystal X-ray diffraction analyses

    Dirhenium carbonyl compounds bearing cis-1,2-bis(diphenylphosphino)ethylene and cis-1,2-bis(diphenylphosphino)ethylene oxide ligands 

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    Reaction of [Re2(CO)9(MeCN)] with cis-1,2-bis(diphenylphosphino)ethylene (cis-Ph2PCH=CHPPh2) in boiling benzene (80 °C) afforded two compounds, ax-[Re2(CO)9(κ1-cis-Ph2PCH=CHPPh2)] (1) and ax-[Re2(CO)9{κ1-cis-Ph2PCH=CHPh2P(O)}] (2) where the ligand is axially coordinated in a κ1 monodentate fashion through phosphorus. The close-bridged compound [Re2(CO)8(μ-κ2-cis-Ph2PCH=CHPPh2)] (3) was obtained from a similar reaction of the same ligand with [Re2(CO)8(NCMe)2] in refluxing benzene. In this case the diphosphine is equatorially coordinated to two Re atoms in a symmetrical bridging fashion. Compounds 1−3 have been characterized by IR, 1H NMR, 31P{1H} NMR spectroscopy and single crystal X-ray diffraction analyses

    Tribological behaviour of microalloyed and conventional C–Mn rail steels in a pure sliding condition

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    This paper compares the tribological behaviour of microalloyed rail steel with conventional C–Mn rail steel under different test conditions (load, temperature and humidity). Pin-on-disc tribological tests were performed inside a climate chamber under different loads (20, 30 and 40 N), relative humidity (15, 55 and 70%) and temperatures (20 and 40 ℃). After the friction and wear tests, the worn surfaces were analysed using both confocal and scanning electron microscopies. The results obtained show that the use of microalloyed steel in railway applications under severe conditions (high loads and humidity) could lead to increased service life of the rails and could extend the time between maintenance operations

    Factors associated with antenatal care adequacy in rural and urban contexts-results from two health and demographic surveillance sites in Vietnam

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    <p>Abstract</p> <p>Background</p> <p>Antenatal Care (ANC) is universally considered important for women and children. This study aims to identify factors, demographic, social and economic, possibly associated with three ANC indicators: number of visits, timing of visits and content of services. The aim is also to compare the patterns of association of such factors between one rural and one urban context in northern Vietnam.</p> <p>Methods</p> <p>Totally 2,132 pregnant women were followed from identification of pregnancy until birth in two Health and Demographic Surveillance Sites (HDSS). Information was obtained through quarterly face to face interviews.</p> <p>Results</p> <p>Living in the rural area was significantly associated with lower adequate use of ANC compared to living in the urban area, both regarding quantity (number and timing of visits) and content. Low education, living in poor households and exclusively using private sector ANC in both sites and self employment, becoming pregnant before 25 years of age and living in poor communities in the rural area turned out to increase the risk for overall inadequate ANC. High risk pregnancy could not be demonstrated to be associated with ANC adequacy in either site. The medical content of services offered was often inadequate, in relation to the national recommendations, especially in the private sector.</p> <p>Conclusion</p> <p>Low education, low economic status, exclusive use of private ANC and living in rural areas were main factors associated with risk for overall inadequate ANC use as related to the national recommendations. Therefore, interventions focussing on poor and less educated women, especially in rural areas should be prioritized. They should focus the importance of early attendance of ANC and sufficient use of core services. Financial support for poor and near poor women should be considered. Providers of ANC should be educated and otherwise influenced to provide sufficient core services. Adherence to ANC content guidelines must be improved through enhanced supervision, particularly in the private sector.</p

    The Australian Racism, Acceptance, and Cultural-Ethnocentrism Scale (RACES): item response theory findings

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    BACKGROUND: Racism and associated discrimination are pervasive and persistent challenges with multiple cumulative deleterious effects contributing to inequities in various health outcomes. Globally, research over the past decade has shown consistent associations between racism and negative health concerns. Such research confirms that race endures as one of the strongest predictors of poor health. Due to the lack of validated Australian measures of racist attitudes, RACES (Racism, Acceptance, and Cultural-Ethnocentrism Scale) was developed. METHODS: Here, we examine RACES’ psychometric properties, including the latent structure, utilising Item Response Theory (IRT). Unidimensional and Multidimensional Rating Scale Model (RSM) Rasch analyses were utilised with 296 Victorian primary school students and 182 adolescents and 220 adults from the Australian community. RESULTS: RACES was demonstrated to be a robust 24-item three-dimensional scale of Accepting Attitudes (12 items), Racist Attitudes (8 items), and Ethnocentric Attitudes (4 items). RSM Rasch analyses provide strong support for the instrument as a robust measure of racist attitudes in the Australian context, and for the overall factorial and construct validity of RACES across primary school children, adolescents, and adults. CONCLUSIONS: RACES provides a reliable and valid measure that can be utilised across the lifespan to evaluate attitudes towards all racial, ethnic, cultural, and religious groups. A core function of RACES is to assess the effectiveness of interventions to reduce community levels of racism and in turn inequities in health outcomes within Australia. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12939-016-0338-4) contains supplementary material, which is available to authorized users

    Nicotinic Receptors Underlying Nicotine Dependence: Evidence from Transgenic Mouse Models.

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    Nicotine underlies the reinforcing properties of tobacco cigarettes and e-cigarettes. After inhalation and absorption, nicotine binds to various nicotinic acetylcholine receptor (nAChR) subtypes localized on the pre- and postsynaptic membranes of cells, which subsequently leads to the modulation of cellular function and neurotransmitter signaling. In this chapter, we begin by briefly reviewing the current understanding of nicotine's actions on nAChRs and highlight considerations regarding nAChR subtype localization and pharmacodynamics. Thereafter, we discuss the seminal discoveries derived from genetically modified mouse models, which have greatly contributed to our understanding of nicotine's effects on the reward-related mesolimbic pathway and the aversion-related habenulo-interpeduncular pathway. Thereafter, emerging areas of research focusing on modulation of nAChR expression and/or function are considered. Taken together, these discoveries have provided a foundational understanding of various genetic, neurobiological, and behavioral factors underlying the motivation to use nicotine and related dependence processes, which are thereby advancing drug discovery efforts to promote long-term abstinence

    Racism as a determinant of health: a systematic review and meta-analysis

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    Despite a growing body of epidemiological evidence in recent years documenting the health impacts of racism, the cumulative evidence base has yet to be synthesized in a comprehensive meta-analysis focused specifically on racism as a determinant of health. This meta-analysis reviewed the literature focusing on the relationship between reported racism and mental and physical health outcomes. Data from 293 studies reported in 333 articles published between 1983 and 2013, and conducted predominately in the U.S., were analysed using random effects models and mean weighted effect sizes. Racism was associated with poorer mental health (negative mental health: r = -.23, 95% CI [-.24,-.21], k = 227; positive mental health: r = -.13, 95% CI [-.16,-.10], k = 113), including depression, anxiety, psychological stress and various other outcomes. Racism was also associated with poorer general health (r = -.13 (95% CI [-.18,-.09], k = 30), and poorer physical health (r = -.09, 95% CI [-.12,-.06], k = 50). Moderation effects were found for some outcomes with regard to study and exposure characteristics. Effect sizes of racism on mental health were stronger in cross-sectional compared with longitudinal data and in non-representative samples compared with representative samples. Age, sex, birthplace and education level did not moderate the effects of racism on health. Ethnicity significantly moderated the effect of racism on negative mental health and physical health: the association between racism and negative mental health was significantly stronger for Asian American and Latino(a) American participants compared with African American participants, and the association between racism and physical health was significantly stronger for Latino(a) American participants compared with African American participants.<br /
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