Solid-state synthesis and characterization of σ-Alkane complexes, [Rh(L2)(η2,η2-C7H12)][BArF4] (L2 = bidentate chelating phosphine)

The use of solid/gas and single-crystal to single-crystal synthetic routes is reported for the synthesis and characterization of a number of σ-alkane complexes: [Rh(R2P(CH2)nPR2)(η2,η2-C7H12)][BArF4]; R = Cy, n = 2; R = iPr, n = 2,3; Ar = 3,5-C6H3(CF3)2. These norbornane adducts are formed by simple hydrogenation of the corresponding norbornadiene precursor in the solid state. For R = Cy (n = 2), the resulting complex is remarkably stable (months at 298 K), allowing for full characterization using single-crystal X-ray diffraction. The solid-state structure shows no disorder, and the structural metrics can be accurately determined, while the 1H chemical shifts of the Rh···H–C motif can be determined using solid-state NMR spectroscopy. DFT calculations show that the bonding between the metal fragment and the alkane can be best characterized as a three-center, two-electron interaction, of which σCH → Rh donation is the major component. The other alkane complexes exhibit solid-state 31P NMR data consistent with their formation, but they are now much less persistent at 298 K and ultimately give the corresponding zwitterions in which [BArF4]− coordinates and NBA is lost. The solid-state structures, as determined by X-ray crystallography, for all these [BArF4]− adducts are reported. DFT calculations suggest that the molecular zwitterions within these structures are all significantly more stable than their corresponding σ-alkane cations, suggesting that the solid-state motif has a strong influence on their observed relative stabilities

Scale-dependent effects of density and habitat on foal survival

Identifying the most appropriate scale to study factors influencing life history is important to evolutionary ecology and wildlife management. For example, the scale at which density is assessed and explains variation in survival can affect how biologists observe and interpret population dynamics, which can influence plans for managing populations. Feral horses (Equus ferus caballus) contrast with most ungulates by exhibiting a mating system characterized by female-defense polygyny with persistent, non-territorial breeding groups (bands) and female-biased initial (natal) and subsequent (breeding) dispersal. We predicted that for horses, offspring movements coupled with female-biased breeding dispersal would increase the scale at which density best related to juvenile survival compared to species with greater female philopatry. From 2008 to 2013, we censused the population of feral horses on Sable Island, Canada. We annually computed individual-specific local densities for 442 foals (horses/km2 in radii of 2,000 m, 4,000 m, and 8,000 m fixed to a band’s centroid of movements) and whole-island (total) population density, group (band) size, and local access to surface freshwater, which affected movement patterns and selection of vegetation by females. The population of feral horses increased from 380 in 2008 to 559 in 2013. Overwinter survival of foals averaged 82.8%. Island-wide density was the most important predictor of foal mortality and was negatively associated with survival, with a lesser negative effect from local density. Increased access to surface freshwater (ponds) was an important predictor of foal survival but only at certain scales. Our study emphasizes the relevance of a multi-scale approach when analyzing the response of fitness components to changes in habitat and population processes, which may be influenced by the particular social organization of the species

Mean field variational bayes for elaborate distributions

We develop strategies for mean field variational Bayes approximate inference for Bayesian hierarchical models containing elaborate distributions. We loosely define elaborate distributions to be those having more complicated forms compared with common distributions such as those in the Normal and Gamma families. Examples are Asymmetric Laplace, Skew Normal and Generalized Extreme Value distributions. Such models suffer from the difficulty that the parameter updates do not admit closed form solutions. We circumvent this problem through a combination of (a) specially tailored auxiliary variables, (b) univariate quadrature schemes and (c) finite mixture approximations of troublesome density functions. An accuracy assessment is conducted and the new methodology is illustrated in an application. © 2011 International Society for Bayesian Analysis

Draft Genome Sequences of Three Strains of Geobacillus stearothermophilus Isolated from a Milk Powder Manufacturing Plant.

Three strains of Geobacillus stearothermophilus (designated A1, P3, and D1) were isolated from a New Zealand milk powder manufacturing plant. Here, we describe their draft genome sequences. This information provided the first genomic insights into the nature of G. stearothermophilus strains present in the milk powder manufacturing environment.Published onlin

Stages of development and injury: an epidemiological survey of young children presenting to an emergency department

<p><b>Background:</b> The aim of our study was to use a local (Glasgow, west of Scotland) version of a Canadian injury surveillance programme (CHIRPP) to investigate the relationship between the developmental stage of young (pre-school) children, using age as a proxy, and the occurrence (incidence, nature, mechanism and location) of injuries presenting to a Scottish hospital emergency department, in an attempt to replicate the findings of a recent study in Kingston, Canada.</p> <p><b>Methods:</b> We used the Glasgow CHIRPP data to perform two types of analyses. First, we calculated injury rates for that part of the hospital catchment area for which reasonably accurate population denominators were available. Second, we examined detailed injury patterns, in terms of the circumstances, mechanisms, location and types of injury. We compared our findings with those of the Kingston researchers.</p> <p><b>Results:</b> A total of 17,793 injury records for children aged up to 7 years were identified over the period 1997–99. For 1997–2001, 6,188 were used to calculate rates in the west of the city only. Average annual age specific rates per 1000 children were highest in both males and females aged 12–35 months. Apart from the higher rates in Glasgow, the pattern of injuries, in terms of breakdown factors, mechanism, location, context, and nature of injury, were similar in Glasgow and Kingston.</p> <p><b>Conclusion:</b> We replicated in Glasgow, UK, the findings of a Canadian study demonstrating a correlation between the pattern of childhood injuries and developmental stage. Future research should take account of the need to enhance statistical power and explore the interaction between age and potential confounding variables such as socio-economic deprivation. Our findings highlight the importance of designing injury prevention interventions that are appropriate for specific stages of development in children.</p&gt

Do HIV treatment eligibility expansions crowd out the sickest? Evidence from rural South Africa

OBJECTIVE: The 2015 WHO recommendation to initiate all HIV patients on antiretroviral therapy (ART) at diagnosis could potentially overextend health systems and crowd out sicker patients, mitigating the policy's impact. We evaluate whether South Africa's prior eligibility expansion from CD4 ≤200 to CD4 ≤350 cells/μL reduced ART uptake in the sickest patients. METHODS: Using data on all patients presenting to the Hlabisa HIV Treatment and Care Program in KwaZulu-Natal from April 2010 - June 2012 (n=13,809), we assessed the impact of the August 2011 eligibility expansion on the number of patients seeking care, number initiating ART, and time from HIV diagnosis to ART initiation among patients always eligible (CD4 0-200), newly eligible (CD4 201-350), and not yet eligible by CD4 count (>350). We used interrupted time series methods to control for long-run trends and isolate the effect of the policy. RESULTS: Expanding ART eligibility led to an increased number of patients initiating ART per month [+95.5; 95% CI (-1.3; 192.3)]. Newly eligible patients (CD4 201-350) initiated treatment 47% faster than before (95% CI 19%; 82%), while the sickest patients (CD4 ≤200) saw no decline in the monthly number of patients initiating treatment or the rate of treatment uptake. CONCLUSION: The Hlabisa program successfully extended ART to patients with CD4 ≤350 cells/μL, while ensuring that the sickest patients did not experience delays in ART initiation. Treatment programs must be vigilant to maintain quality of care for the sickest as countries move to treat all patients irrespective of CD4 count. This article is protected by copyright. All rights reserved

CYP2D6 variants and the prediction of tamoxifen response in randomized patients: author response

and letter by Rae et al. onlin

Modulation of adipocyte G-protein expression in cancer cachexia by a lipid-mobilizing factor (LMF)

Adipocytes isolated from cachectic mice bearing the MAC 16 tumour showed over a 3-fold increase in lipolytic response to both low concentrations of isoprenaline and a tumour-derived lipid mobilizing factor (LMF). This was reflected by an enhanced stimulation of adenylate cyclase in plasma membrane fractions of adipocytes in the presence of both factors. There was no up-regulation of adenylate cyclase in response to forskolin, suggesting that the effect arose from a change in receptor number or G-protein expression. Immunoblotting of adipocyte membranes from mice bearing the MAC16 tumour showed an increased expression of Gαs up to 10% weight loss and a reciprocal decrease in Gα. There was also an increased expression of Gαs and a decrease in Gα in adipose tissue from a patient with cancer-associated weight loss compared with a non-cachectic cancer patient. The changes in G-protein expression were also seen in adipose tissue of normal mice administered pure LMF as well as in 3T3L1 adipocytes in vitro. The changes in G-protein expression induced by LMF were attenuated by the polyunsaturated fatty acid, eicosapentaenoic acid (EPA). This suggests that this tumour-derived lipolytic factor acts to sensitize adipose tissue to lipolytic stimuli, and that this effect is attenuated by EPA, which is known to preserve adipose tissue in cancer cachexia. © 2001 Cancer Research Campaig