4,337 research outputs found

    Theoretical investigation of the scope of sequential ligand tuning using a bifunctional scorpionate tris(1,2,4-triazolyl)borate-based architecture

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    The donor properties of a series of tripodal mixed N-donor/carbene ligands derived through sequential alkylation of hydrotris(1,2,4-triazolyl)borate have been investigated by density functional theory (DFT) methods. The structures of complexes of the form [Mo(L)(CO)3]- were optimized (L = [HB(1,2,4-triazolyl)n(1,2,4-triazol-5-ylidene)3-n]- (n = 0 – 3), hydrotris(pyrazolyl)borate, hydrotris(3,5-dimethylpyrazolyl)borate and hydrotris(imidazol-2-ylidene)borate) and nuCO frequencies for these complexes and partial charges of their Mo(CO)3 fragments were determined. Results show that ligand donation is highly tunable when compared to similar experimentally known ligands with a shift in the symmetric nuCO stretching mode of -39 cm -1 on going from the tris(1,2,4-triazolyl)borate complexes to that of the triscarbene hydrotris(1,2,4-triazol-5-ylidene) and an increase in partial charge (distributed multipole analysis) of the Mo(CO)3 fragment from -0.23 to -0.48

    Effect of lower sodium intake on health: systematic review and meta-analyses

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    Objective To assess the effect of decreased sodium intake on blood pressure, related cardiovascular diseases, and potential adverse effects such as changes in blood lipids, catecholamine levels, and renal function. Design Systematic review and meta-analysis. Data sources Cochrane Central Register of Controlled Trials, Medline, Embase, WHO International Clinical Trials Registry Platform, the Latin American and Caribbean health science literature database, and the reference lists of previous reviews. Study selection Randomised controlled trials and prospective cohort studies in non-acutely ill adults and children assessing the relations between sodium intake and blood pressure, renal function, blood lipids, and catecholamine levels, and in non-acutely ill adults all cause mortality, cardiovascular disease, stroke, and coronary heart disease. Study appraisal and synthesis Potential studies were screened independently and in duplicate and study characteristics and outcomes extracted. When possible we conducted a meta-analysis to estimate the effect of lower sodium intake using the inverse variance method and a random effects model. We present results as mean differences or risk ratios, with 95% confidence intervals. Results We included 14 cohort studies and five randomised controlled trials reporting all cause mortality, cardiovascular disease, stroke, or coronary heart disease; and 37 randomised controlled trials measuring blood pressure, renal function, blood lipids, and catecholamine levels in adults. Nine controlled trials and one cohort study in children reporting on blood pressure were also included. In adults a reduction in sodium intake significantly reduced resting systolic blood pressure by 3.39 mm Hg (95% confidence interval 2.46 to 4.31) and resting diastolic blood pressure by 1.54 mm Hg (0.98 to 2.11). When sodium intake was 0.05). There were insufficient randomised controlled trials to assess the effects of reduced sodium intake on mortality and morbidity. The associations in cohort studies between sodium intake and all cause mortality, incident fatal and non-fatal cardiovascular disease, and coronary heart disease were non-significant (P>0.05). Increased sodium intake was associated with an increased risk of stroke (risk ratio 1.24, 95% confidence interval 1.08 to 1.43), stroke mortality (1.63, 1.27 to 2.10), and coronary heart disease mortality (1.32, 1.13 to 1.53). In children, a reduction in sodium intake significantly reduced systolic blood pressure by 0.84 mm Hg (0.25 to 1.43) and diastolic blood pressure by 0.87 mm Hg (0.14 to 1.60). Conclusions High quality evidence in non-acutely ill adults shows that reduced sodium intake reduces blood pressure and has no adverse effect on blood lipids, catecholamine levels, or renal function, and moderate quality evidence in children shows that a reduction in sodium intake reduces blood pressure. Lower sodium intake is also associated with a reduced risk of stroke and fatal coronary heart disease in adults. The totality of evidence suggests that most people will likely benefit from reducing sodium intake

    Symmetry of k·p Hamiltonian in pyramidal InAs/GaAs quantum dots: Application to the calculation of electronic structure

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    A method for the calculation of the electronic structure of pyramidal self-assembled InAs/GaAs quantum dots is presented. The method is based on exploiting the C-4 symmetry of the 8-band k·p Hamiltonian with the strain taken into account via the continuum mechanical model. The operators representing symmetry group elements were represented in the plane wave basis and the group projectors were used to find the symmetry adapted basis in which the corresponding Hamiltonian matrix is block diagonal with four blocks of approximately equal size. The quantum number of total quasiangular momentum is introduced and the states are classified according to its value. Selection rules for interaction with electromagnetic field in the dipole approximation are derived. The method was applied to calculate electron and hole quasibound states in a periodic array of vertically stacked pyramidal self-assembled InAs/GaAs quantum dots for different values of the distance between the dots and external axial magnetic field. As the distance between the dots in an array is varied, an interesting effect of simultaneous change of ground hole state symmetry, type, and the sign of miniband effective mass is predicted. This effect is explained in terms of the change of biaxial strain. It is also found that the magnetic field splitting of Kramer's double degenerate states is most prominent for the first and second excited state in the conduction band and that the magnetic field can both separate otherwise overlapping minibands and concatenate otherwise nonoverlapping minibands

    Circulatory proteins relate cardiovascular disease to cognitive performance: a Mendelian randomisation study

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    Background and objectives: Mechanistic research suggests synergistic effects of cardiovascular disease (CVD) and dementia pathologies on cognitive decline. Interventions targeting proteins relevant to shared mechanisms underlying CVD and dementia could also be used for the prevention of cognitive impairment. Methods: We applied Mendelian randomisation (MR) and colocalization analysis to investigate the causal relationships of 90 CVD-related proteins measured by the Olink CVD I panel with cognitive traits. Genetic instruments for circulatory protein concentrations were obtained using a meta-analysis of genome-wide association studies (GWAS) from the SCALLOP consortium (N = 17,747) based on three sets of criteria: 1) protein quantitative trait loci (pQTL); 2) cis-pQTL (pQTL within ±500 kb from the coding gene); and 3) brain-specific cis-expression QTL (cis-eQTL) which accounts for coding gene expression based on GTEx8. Genetic associations of cognitive performance were obtained from GWAS for either: 1) general cognitive function constructed using Principal Component Analysis (N = 300,486); or, 2) g Factor constructed using genomic structural equation modelling (N = 11,263–331,679). Findings for candidate causal proteins were replicated using a separate protein GWAS in Icelanders (N = 35,559). Results: A higher concentration of genetically predicted circulatory myeloperoxidase (MPO) was nominally associated with better cognitive performance (p < 0.05) using different selection criteria for genetic instruments. Particularly, brain-specific cis-eQTL predicted MPO, which accounts for protein-coding gene expression in brain tissues, was associated with general cognitive function (βWald = 0.22, PWald = 2.4 × 10−4). The posterior probability for colocalization (PP.H4) of MPO pQTL with the g Factor was 0.577. Findings for MPO were replicated using the Icelandic GWAS. Although we did not find evidence for colocalization, we found that higher genetically predicted concentrations of cathepsin D and CD40 were associated with better cognitive performance and a higher genetically predicted concentration of CSF-1 was associated with poorer cognitive performance. Conclusion: We conclude that these proteins are involved in shared pathways between CVD and those for cognitive reserve or affecting cognitive decline, suggesting therapeutic targets able to reduce genetic risks conferred by cardiovascular disease

    Happy Little Nigs / words by George Elliott

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    Cover: drawing of young African Americans dancing as an older African American male plays the banjo; description reads rag two step; Publisher: W. J. Dyer and Bro. (Saint Paul)https://egrove.olemiss.edu/sharris_a/1029/thumbnail.jp

    Renewing the Exploration Approach for Mid-Enthalpy Systems: Examples from Northern England and Scotland

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    After a promising start in the 1970s and 80s, the UK rather fell behind other countries in the search for viable mid-enthalpy geothermal resources. This situation began to turn around in 2004, when the first of three deep geothermal exploration boreholes were drilled in northern England. What distinguished these from earlier drilling in Cornwall was the deliberate search for naturallyhigh permeability associated with major faults, especially those that have undergone strike-slip reactivation during the Cenozoic. Boreholes at Eastgate in the North Pennines targeted buried radiothermal granite, whereas the 1,821m-deep Science Central Borehole in Newcastle upon Tyne targeted a postulated deep sedimentary aquifer (the Fell Sandstones), which were inferred to be connected laterally to the granitic heat source by a major fault (the reactivation of the Iapetus geo-suture). The drilling was in both cases rewarded with impressive heat flows, and in the case of Eastgate with what is believed to be the highest permeability yet found in a deep granite batholith anywhere in the world. In parallel with these developments, a re-assessment was made of the preexisting geothermal heat flow database for the UK, applying newly-standardised correction protocols for palaeoclimatic and topographic distortions, which were found to be particularly marked in Scotland (where only shallow boreholes had been used to establish geothermal gradients in the original 1980s analysis), Similar prospects in northern England (similar to that drilled at Science Central) are now the focus of commercial exploration efforts. Appraisal of fault dispositions relative to the present-day maximum compressive stress azimuth are being used to identify the most promising areas for intersecting fault-related permeability at depth. New geophysical tools – most notably atomic dielectric resonance scanning – are also being appraised for their ability to directly detect features (such as hot brines) which are indicative of localised convection in target fault zones and aquifers

    Perspectives on pre-exposure prophylaxis for people who inject drugs in the context of an HIV outbreak: a qualitative study

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    Background: There is an ongoing HIV outbreak amongst people who inject drugs (PWID) in Glasgow, Scotland, and one response which has not yet been widely implemented is the provision of Pre-exposure prophylaxis (PrEP). PrEP is the use of HIV anti-retrovirals prior to HIV infection to provide a barrier to infection. This has been shown to be effective amongst various at-risk populations in preventing HIV spread. The present study aimed to explore views of PWID who might benefit from PrEP provision and Service Providers working with PWID to understand will to use PrEP and literacy of PrEP, contributing to the development of a PrEP service. Methods: A qualitative approach was taken, with semi structured interviews conducted in Glasgow at two third sector service sites. 11 Service Providers and 21 PWID participated in the study. Data was analysed thematically. Results: Participants, both PWID and Service Providers, were keen to engage with PrEP and perceived substantial potential benefits of PrEP for this population. Potential barriers to engagement were identified as a lack of health literacy, motivation, and self-ascribed risk, as well as the overwhelming unpredictability of substance use. Participants wanted PrEP to be provided within already existing structures, particularly community pharmacies, and for promotion and provision to involve peers. Conclusion: This sample reported willingness to engage with PrEP, and suggested there is a specific need amongst PWID for PrEP. However, PWID have specific lived experienced contexts and needs, and are burdened by social and economic marginalisation and inequality at every level. This contrasts them from other populations currently being provided with PrEP, and must be considered in the development of provision

    Prey consumption rates and growth of piscivorous brown trout in a subarctic watercourse

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    This is the peer reviewed version of the following article: Jensen, H., Amundsen, P.-A., Elliott, J.M., Bøhn, T. & Aspholm, P.E. (2006). Prey consumption rates and growth of piscivorous brown trout in a subarctic watercourse. Journal of Fish Biology, 68(3), 838-848, which has been published in final form at https://doi.org/10.1111/j.0022-1112.2006.00972.x. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.Prey consumption rates of piscivorous brown trout Salmo trutta were studied in the Pasvik watercourse, which forms the border between Norway and Russia. Estimates of food consumption in the field were similar to or slightly less than maximum values from a bioenergetic model. The piscivore diet consisted mainly of vendace Coregonus albula with a smaller number of whitefish Coregonus lavaretus. Individual brown trout had an estimated mean daily intake of c. 1·5 vendace and 0·4 whitefish, and a rapid annual growth increment of 7–8 cm year−1. The total population of brown trout >25 cm total length was estimated as 8445 individuals (0·6 individuals ha−1), giving a mean ± s.e. annual consumption of 1553880 ± 405360 vendace and 439140 ± 287130 whitefish for the whole watercourse. The rapid growth in summer of brown trout >25 cm indicated a high prey consumption rate

    Multidisciplinary analysis of a mummified cranium claimed to be that of a medieval execution victim

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    This article presents a multidisciplinary analysis of a human skull with preserved soft tissue curated by a small museum in Boscastle, Cornwall, UK. The skull lacks a mandible and is coated in a black tar-like substance. Records left by a previous museum curator (now deceased) claimed the skull to be the head of a medieval execution victim. The skull was purportedly recovered from a London church that was destroyed during the Second World War where it had been kept in a carved oak box. If these details are correct, the skull would appear to have been venerated as a relic. The skull and box have been analysed using a range of techniques including computerised tomography, laser scanning, microscopy, infrared spectroscopy and radiocarbon dating. These analyses demonstrated the skull in fact to be that of an Egyptian mummy dating from the Ptolemaic period. Other instances have been noted of parts of Egyptian mummies being presented as European saintly relics, and the ‘Boscastle skull’ would appear to be an example of such. A wider point illustrated by the work presented here is that sufficient application of modern analytical techniques may reveal considerable information regarding human remains which otherwise have little or no provenance. This point strengthens arguments for the retention of such remains by curating institutions
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