39 research outputs found

    Distribution, variability and sources of tropospheric ozone over south China in spring: intensive ozonesonde measurements at five locations and modeling analysis

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    We examine the characteristics of the spatial distribution and variability of tropospheric ozone (O3) by analysis of 93 ozonesonde profiles obtained at five stations over south China (18–30 N) during a field campaign in April–May 2004. We use a global 3-D chemical transport model (GEOS-Chem) to interpret these characteristics and to quantify the sources of tropospheric O3 over south China during this period. The observed tropospheric O3 mixing ratios showed strong spatiotemporal variability due to a complex interplay of various dynamical and chemical processes. A prominent feature in the upper and middle troposphere (UT/MT) was the frequent occurrence of high O3 mixing ratios shown as tongues extending down from the lower stratosphere or as isolated layers at all stations. The model largely captured the observed pattern of day-to-day variability in tropospheric O3 mixing ratios at all stations, but often underestimated those tongues or isolated layers of O3 enhancements observed in the UT/MT, especially at low-latitude stations. We found that tropospheric O3 along the southeast China coast was mainly produced within Asia. Lightning NOx emissions (over South Asia and equatorial Africa) and/or stratospheric influences were responsible for major events of high O3 observed in the UT/MT at all stations. Underestimated contributions of these sources likely led to the model’s underestimate in the low-latitude UT/MT O3. This study emphasizes the need for improved understanding of lightning NOx emissions and stratospheric influences over the Eurasian and African continents and for better representation of these processes in current global models

    Activity, stability and 3-D structure of the Cu(II) form of a chitin-active lytic polysaccharide monooxygenase from Bacillus amyloliquefaciens

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    The enzymatic deconstruction of recalcitrant polysaccharide biomass is central to the conversion of these substrates for societal benefit, such as in biofuels. Traditional models for enzyme-catalysed polysaccharide degradation involved the synergistic action of endo-, exo-and processive glycoside hydrolases working in concert to hydrolyse the substrate. More recently this model has been succeeded by one featuring a newly discovered class of mononuclear copper enzymes: lytic polysaccharide monooxygenases (LPMOs; classified as Auxiliary Activity (AA) enzymes in the CAZy classification). In 2013, the structure of an LPMO from Bacillus amyloliquefaciens, BaAA10, was solved with the Cu centre photoreduced to Cu(I) in the X-ray beam. Here we present the catalytic activity of BaAA10. We show that it is a chitin-active LPMO, active on both α and β chitin, with the Cu(II) binding with low nM KD, and the substrate greatly increasing the thermal stability of the enzyme. A spiral data collection strategy has been used to facilitate access to the previously unobservable Cu(II) state of the active centre, revealing a coordination geometry around the copper which is distorted from axial symmetry, consistent with the previous findings from EPR spectroscopy

    Altered mGluR5-Homer scaffolds and corticostriatal connectivity in a Shank3 complete knockout model of autism

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    Human neuroimaging studies suggest that aberrant neural connectivity underlies behavioural deficits in autism spectrum disorders (ASDs), but the molecular and neural circuit mechanisms underlying ASDs remain elusive. Here, we describe a complete knockout mouse model of the autism-associated Shank3 gene, with a deletion of exons 4–22 (Δe4–22). Both mGluR5-Homer scaffolds and mGluR5-mediated signalling are selectively altered in striatal neurons. These changes are associated with perturbed function at striatal synapses, abnormal brain morphology, aberrant structural connectivity and ASD-like behaviour. In vivo recording reveals that the cortico-striatal-thalamic circuit is tonically hyperactive in mutants, but becomes hypoactive during social behaviour. Manipulation of mGluR5 activity attenuates excessive grooming and instrumental learning differentially, and rescues impaired striatal synaptic plasticity in Δe4–22−/− mice. These findings show that deficiency of Shank3 can impair mGluR5-Homer scaffolding, resulting in cortico-striatal circuit abnormalities that underlie deficits in learning and ASD-like behaviours. These data suggest causal links between genetic, molecular, and circuit mechanisms underlying the pathophysiology of ASDs

    Genomic Relationships, Novel Loci, and Pleiotropic Mechanisms across Eight Psychiatric Disorders

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    Genetic influences on psychiatric disorders transcend diagnostic boundaries, suggesting substantial pleiotropy of contributing loci. However, the nature and mechanisms of these pleiotropic effects remain unclear. We performed analyses of 232,964 cases and 494,162 controls from genome-wide studies of anorexia nervosa, attention-deficit/hyper-activity disorder, autism spectrum disorder, bipolar disorder, major depression, obsessive-compulsive disorder, schizophrenia, and Tourette syndrome. Genetic correlation analyses revealed a meaningful structure within the eight disorders, identifying three groups of inter-related disorders. Meta-analysis across these eight disorders detected 109 loci associated with at least two psychiatric disorders, including 23 loci with pleiotropic effects on four or more disorders and 11 loci with antagonistic effects on multiple disorders. The pleiotropic loci are located within genes that show heightened expression in the brain throughout the lifespan, beginning prenatally in the second trimester, and play prominent roles in neurodevelopmental processes. These findings have important implications for psychiatric nosology, drug development, and risk prediction.Peer reviewe

    Practical Recommendations for Long-term Management of Modifiable Risks in Kidney and Liver Transplant Recipients

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    Data extraction template.

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    BackgroundClimate Change (CC) emanating from anthropocentric human activities is a great threat to the quality of human life and well-being worldwide. The translation of CC research evidence can play a critical role in promoting the formulation of climate-sensitive policies to equip public health systems for CC-associated disaster preparedness, response, and management. This scoping review seeks to explore knowledge translation approaches for promoting, the uptake, and use of CC research evidence in public health policy and practice.MethodsThis scoping review will be conducted according to the guidelines of Arksey and O’Malley. A search strategy will be developed for published articles in PubMed, CINAHL, and Scopus databases and for grey literature in the World Health Organization, Planetary Health Alliance, and the University of the Western Cape repositories.DiscussionThe proposed scoping review will gather existing evidence on the relationship between knowledge translation, CC research, and public health decision-making. This will provide insights into research and practice gaps, and recommendations will be made to ensure effective knowledge translation for CC related decision-making.</div

    PRISMA-P checklist.

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    BackgroundClimate Change (CC) emanating from anthropocentric human activities is a great threat to the quality of human life and well-being worldwide. The translation of CC research evidence can play a critical role in promoting the formulation of climate-sensitive policies to equip public health systems for CC-associated disaster preparedness, response, and management. This scoping review seeks to explore knowledge translation approaches for promoting, the uptake, and use of CC research evidence in public health policy and practice.MethodsThis scoping review will be conducted according to the guidelines of Arksey and O’Malley. A search strategy will be developed for published articles in PubMed, CINAHL, and Scopus databases and for grey literature in the World Health Organization, Planetary Health Alliance, and the University of the Western Cape repositories.DiscussionThe proposed scoping review will gather existing evidence on the relationship between knowledge translation, CC research, and public health decision-making. This will provide insights into research and practice gaps, and recommendations will be made to ensure effective knowledge translation for CC related decision-making.</div
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