593 research outputs found

    A general catalytic β-C-H carbonylation of aliphatic amines to β-lactams

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    Methods for the synthesis and functionalization of amines are intrinsically important to a variety of chemical applications. We present a general carbon-hydrogen bond activation process that combines readily available aliphatic amines and the feedstock gas carbon monoxide to form synthetically versatile value-added amide products. The operationally straightforward palladium-catalyzed process exploits a distinct reaction pathway, wherein a sterically hindered carboxylate ligand orchestrates an amine attack on a palladium anhydride to transform aliphatic amines into β-lactams. The reaction is successful with a wide range of secondary amines and can be used as a late-stage functionalization tactic to deliver advanced, highly functionalized amine products of utility for pharmaceutical research and other areas.We gratefully acknowledge funding from the European Research Council and the UK Engineering and Physical Sciences Research Council (EPSRC) (to D.W., K.F.H., A.P.S., and M.J.G.), the Herchel Smith Trust (to B.G.N.C.), the Marie Curie Foundation (to J.C.), and the Royal Society (Wolfson Merit Award to M.J.G.). Mass spectrometry data were acquired at the EPSRC UK National Mass Spectrometry Facility at Swansea University. Computational work was performed with the Darwin Supercomputer of the University of Cambridge High Performance Computing Service (http://www.hpc.cam.ac.uk/), provided by Dell, using Strategic Research Infrastructure Funding from the Higher Education Funding Council for England

    A mechanistic modelling approach for the determination of the mechanisms of inhibition by cyclosporine on the uptake and metabolism of atorvastatin in rat hepatocytes using a high throughput uptake method

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    (1) Determine the inhibition mechanism through which cyclosporine inhibits the uptake and metabolism of atorvastatin in fresh rat hepatocytes using mechanistic models applied to data generated using a high throughput oil spin method. (2) Atorvastatin was incubated in fresh rat hepatocytes (0.05–150 nmol/ml) with or without 20 min pre-incubation with 10 nmol/ml cyclosporine and sampled over 0.25–60 min using a high throughput oil spin method. Micro-rate constant and macro-rate constant mechanistic models were ranked based on goodness of fit values. (3) The best fitting model to the data was a micro-rate constant mechanistic model including non-competitive inhibition of uptake and competitive inhibition of metabolism by cyclosporine (Model 2). The association rate constant for atorvastatin was 150-fold greater than the dissociation rate constant and 10-fold greater than the translocation into the cell. The association and dissociation rate constants for cyclosporine were 7-fold smaller and 10-fold greater, respectively, than atorvastatin. The simulated atorvastatin-transporter-cyclosporine complex derived using the micro-rate constant parameter estimates increased in line with the incubation concentration of atorvastatin. (4) The increased amount of data generated with the high throughput oil spin method, combined with a micro-rate constant mechanistic model helps to explain the inhibition of uptake by cyclosporine following pre-incubation

    Partial Volume Correction in Arterial Spin Labeling Perfusion MRI: A method to disentangle anatomy from physiology or an analysis step too far?

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    The mismatch in the spatial resolution of Arterial Spin Labeling (ASL) MRI perfusion images and the anatomy of functionally distinct tissues in the brain leads to a partial volume effect (PVE), which in turn confounds the estimation of perfusion to a specific tissue of interest such as grey or white matter. This confound occurs because the image voxels contain a mixture of tissues with disparate perfusion properties, leading to estimated perfusion values that reflect primarily the volume proportions of tissues in the voxel rather than the perfusion of any particular tissue of interest within that volume. It is already recognized that PVE influences studies of brain perfusion, and that its effect might be even more evident in studies where changes in perfusion are co-incident with alterations in brain structure, such as studies involving a comparison between an atrophic patient population vs control subjects, or studies comparing subjects over a wide range of ages. However, the application of PVE correction (PVEc) is currently limited and the employed methodologies remain inconsistent. In this article, we outline the influence of PVE in ASL measurements of perfusion, explain the main principles of PVEc, and provide a critique of the current state of the art for the use of such methods. Furthermore, we examine the current use of PVEc in perfusion studies and whether there is evidence to support its wider adoption. We conclude that there is sound theoretical motivation for the use of PVEc alongside conventional, 'uncorrected', images, and encourage such combined reporting. Methods for PVEc are now available within standard neuroimaging toolboxes, which makes our recommendation straightforward to implement. However, there is still more work to be done to establish the value of PVEc as well as the efficacy and robustness of existing PVEc methods

    Complete mitochondrial genomes and nuclear ribosomal RNA operons of two species of Diplostomum (Platyhelminthes: Trematoda): a molecular resource for taxonomy and molecular epidemiology of important fish pathogens

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    © 2015 Brabec et al. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http:// creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. The attached file is the published version of the article

    Prognostic and Mechanistic Potential of Progesterone Sulfates in Intrahepatic Cholestasis of Pregnancy and Pruritus Gravidarum

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    A challenge in obstetrics is to distinguish pathological symptoms from those associated with normal changes of pregnancy, typified by the need to differentiate whether gestational pruritus of the skin is an early symptom of intrahepatic cholestasis of pregnancy (ICP) or due to benign pruritus gravidarum. ICP is characterized by raised serum bile acids and complicated by spontaneous preterm labor and stillbirth. A biomarker for ICP would be invaluable for early diagnosis and treatment and to enable its differentiation from other maternal diseases. Three progesterone sulfate compounds, whose concentrations have not previously been studied, were newly synthesized and assayed in the serum of three groups of ICP patients and found to be significantly higher in ICP at 9-15 weeks of gestation and prior to symptom onset (group 1 cases/samples: ICP n = 35/80, uncomplicated pregnancy = 29/100), demonstrating that all three progesterone sulfates are prognostic for ICP. Concentrations of progesterone sulfates were associated with itch severity and, in combination with autotaxin, distinguished pregnant women with itch that would subsequently develop ICP from pruritus gravidarum (group 2: ICP n = 41, pruritus gravidarum n = 14). In a third group of first-trimester samples all progesterone sulfates were significantly elevated in serum from low-risk asymptomatic women who subsequently developed ICP (ICP/uncomplicated pregnancy n = 54/51). Finally, we show mechanistically that progesterone sulfates mediate itch by evoking a Tgr5-dependent scratch response in mice. Conclusion: Our discovery that sulfated progesterone metabolites are a prognostic indicator for ICP will help predict onset of ICP and distinguish it from benign pruritus gravidarum, enabling targeted obstetric care to a high-risk population. Delineation of a progesterone sulfate-TGR5 pruritus axis identifies a therapeutic target for itch management in ICP

    Efficacy of a 3 month training program on the jump-landing technique in jump-landing sports. Design of a cluster randomized controlled trial

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    <p>Abstract</p> <p>Background</p> <p>With the relatively high rate of injuries to the lower extremity due to jump-landing movement patterns and the accompanied high costs, there is need for determining potential preventive programs. A program on the intervention of jump-landing technique is possibly an important preventative measure since it appeared to reduce the incidence of lower extremity injuries. In real life situations, amateur sports lack the infrastructure and funds to have a sports physician or therapist permanently supervising such a program. Therefore the current prevention program is designed so that it could be implemented by coaches alone.</p> <p>Objective</p> <p>The objective of this randomized controlled trial is to evaluate the effect of a coach supervised intervention program targeting jump-landing technique on the incidence of lower extremity injuries.</p> <p>Methods</p> <p>Of the 110 Flemish teams of the elite division, 24 teams are included and equally randomized to two study groups. An equal selection of female and male teams with allocation to intervention and control group is obtained. The program is a modification of other prevention programs previously proven to be effective. All exercises in the current program are adjusted so that a more progressive development in the exercise is presented. Both the control and intervention group continue with their normal training routine, while the intervention group carries out the program on jump-landing technique. The full intervention program has a duration of three months and is performed 2 times a week during warm-up (5-10 min). Injuries are registered during the entire season.</p> <p>Discussion</p> <p>The results of this study can give valuable information on the effect of a coach supervised intervention program on jump-landing technique and injury occurrence. Results will become available in 2011.</p> <p>Trial registration</p> <p>Trial registration number: NTR2560</p

    A comparision of GHG emissions from UK field crop production under selected arable systems with reference to disease control

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    Crop disease not only threatens global food security by reducing crop production at a time of growing demand, but also contributes to greenhouse gas (GHG) emissions by reducing efficiency of N fertiliser use and farm operations and by driving land use change. GHG emissions associated with adoption of reduced tillage, organic and integrated systems of field crop production across the UK and selected regions are compared with emissions from conventional arable farming to assess their potential for climate change mitigation. The reduced tillage system demonstrated a modest (<20%) reduction in emissions in all cases, although in practice it may not be suitable for all soils and it is likely to cause problems with control of diseases spread on crop debris. There were substantial increases in GHG emissions associated with the organic and integrated systems at national level, principally due to soil organic carbon losses from land use change. At a regional level the integrated system shows the potential to deliver significant emission reductions. These results indicate that the conventional crop production system, coupled to reduced tillage cultivation where appropriate, is generally the best for producing high yields to minimise greenhouse gas emissions and contribute to global food security, although there may be scope for use of the integrated system on a regional basis. The control of crop disease will continue to have an essential role in both maintaining productivity and decreasing GHG emissions.Peer reviewe

    A mixed methods study of hope, transitions, and quality of life in family caregivers of persons with Alzheimer's disease

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    <p>Abstract</p> <p>Background</p> <p>Several research studies have reported the poor quality of life of family caregivers of persons with Alzheimer's disease (AD). However, factors that influence their quality of life have not been clearly defined. The purpose of this study was to examine factors associated with the quality of life of these caregivers such as demographic variables, their transition experience, and hope. A secondary aim was to explore the transition experience of family caregivers of persons with AD.</p> <p>Methods</p> <p>A cross-sectional triangulation data transformation model mixed method design (Quant +Qual) was utilized to address the purpose of the study. Eighty family caregivers of persons with AD completed a survey with quantitative measures [demographic variables, Herth Hope Index (HHI-hope), World Health Organization Quality of Life -BREF (WHOQOL-BREF)] and a qualitative survey about their transitions experience. The qualitative data (transition open ended- survey) was converted to quantitative data using content analysis. Variables significant at the p < 0.10 level in the univariate analysis were entered in the multivariate generalized linear model used to determine significant factors associated with quality of life.</p> <p>Results</p> <p>Subjects with higher hope scores (p < 0.0001) (Factor 1: temporality and future-cognitive-temporary dimension of hope) and who dealt with their transitions by actively seeking out knowledge and assistance (p = 0.02) had higher overall quality of life scores. HHI scores were associated with overall quality of life and for each of the four quality of life domains (physical psychosocial, relationships, and environment).</p> <p>Conclusions</p> <p>Hope played a significant role in the subjects' perceptions of overall quality of life as well as the 4 quality of life domains. This underscores the need to develop ways to foster hope in family caregivers. Moreover, the active engagement of families in seeking information and help, as a way to deal with their transitions, suggests encouraging this engagement is important. The findings of this study also suggest many directions for future research, such as increasing our understanding of the processes of transitions for this population.</p
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