4,776 research outputs found

    Small-Scale Electric Vehicle DC-DC Converter for Nano-Grids Applications

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    Have you ever wondered what it would be like to have a self-sustained charging system that does not cost you any money on your electric bill? Electric car owners know that even though their cars do not require gasoline to run, they will require electricity and like everyone else that is tied to the grid will have to pay a price per kilowatt hour that is determined by their utility company. With gasoline prices falling somewhat in the past year the hype of electric vehicles has been somewhat less but who knows what the oil market is going to be like in the future, so why not be prepared. Our paper involves implementing an electric vehicle charging station that uses harvested energy from the sun

    Resistance Evolution Against Antimicrobial Peptides in Staphylococcus aureus Alters Pharmacodynamics Beyond the MIC

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    Antimicrobial peptides (AMPs) have been proposed as a promising class of new antimicrobials partly because they are less susceptible to bacterial resistance evolution. This is possibly caused by their mode of action but also by their pharmacodynamic characteristics, which differ significantly from conventional antibiotics. Although pharmacodynamics of antibiotic resistant strains have been studied, such data are lacking for AMP resistant strains. Here, we investigated if the pharmacodynamics of the Gram-positive human pathogen Staphylococcous aureus evolve under antimicrobial peptide selection. Interestingly, the Hill coefficient (kappa κ) evolves together with the minimum inhibition concentration (MIC). Except for one genotype, strains harboring mutations in menF and atl, all mutants had higher kappa than the non-selected sensitive controls. Higher κ results in steeper pharmacodynamic curve and, importantly, in a narrower mutant selection window. S. aureus selected for resistance to melittin displayed cross resistant against pexiganan and had as steep pharmacodynamic curves (high κ) as pexiganan-selected lines. By contrast, the pexiganan-sensitive tenecin-selected lines displayed lower κ. Taken together, our data demonstrate that pharmacodynamic parameters are not fixed traits of particular drug/strain interactions but actually evolve under drug treatment. The contribution of factors such as κ and the maximum and minimum growth rates on the dynamics and probability of resistance evolution are open questions that require urgent attention

    Identification of genes differentially expressed between benign and osteopontin transformed rat mammary epithelial cells

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    <p>Abstract</p> <p>Background</p> <p>Osteopontin is a secreted, integrin-binding and phosphorylated acidic glycoprotein which has an important role in tumor progression.</p> <p>Findings</p> <p>In this study, we have utilized suppressive subtractive hybridization (SSH) to evaluate OPN regulated gene expression, using the Rama 37 benign non-invasive rat mammary cell line and a subclone, Rama 37-OPN. Rama 37-OPN was produced by stably transfecting Rama 37 with an OPN expression vector and it demonstrates increased malignant properties <it>in vitro</it>. Sequence and expression array analysis of the respective cDNA libraries of over 1600 subtracted cDNA fragments revealed 982 ESTs, 45 novel sequences and 659 known genes. The known up-regulated genes in the Rama 37-OPN library code for proteins with a variety of functions including those involved in metabolism, cell adhesion and migration, signal transduction and in apoptosis. Four of the most differentially expressed genes between the benign and <it>in vitro </it>malignant rat mammary cell lines are tumor protein translationally controlled I (TPTI), aryl hydrocarbon receptor nuclear translocator (ARNT), ataxia telangiectasia mutated (ATM) and RAN GTPase (RAN). The largest difference (ca 10,000 fold) between the less aggressively (MCF-7, ZR-75) and more aggressively malignant (MDA MB 231, MDA MB 435S) human breast cancer cell lines is that due to RAN, the next is that due to osteopontin itself.</p> <p>Conclusion</p> <p>The results suggest that enhanced properties associated with the malignant state <it>in vitro </it>induced by osteopontin may be due to, in part, overexpression of RAN GTPase and these biological results are the subject of a subsequent publication <abbrgrp><abbr bid="B1">1</abbr></abbrgrp>.</p

    A pilot study in humans of microneedle sensor arrays for continuous glucose monitoring

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    Although subcutaneously implanted continuous glucose monitoring (CGM) devices have been shown to support diabetes self-management, their uptake remains low due to a combination of high manufacturing cost and limited accuracy and precision arising from their invasiveness. To address these points, minimally invasive, a solid microneedle array-based sensor for continuous glucose monitoring is reported here. These intradermal solid microneedle CGM sensors are designed for low cost manufacturing. The tolerability and performance of these devices is demonstrated through clinical studies, both in healthy volunteers and participants with type 1 diabetes (T1D). The geometry of these solid microneedles allows them to penetrate dermal tissue without the need for an applicator. The outer surface of these solid microneedles are modified as glucose biosensors. The microneedles sit in the interstitial fluid of the skin compartment and monitor real-time changes in glucose concentration. Optical coherence tomography measurements revealed no major axial movement of the microneedles in the tissue. No significant adverse events were observed and low pain scores were reported when compared to catheter insertion, deeming it safe for clinical studies in T1D. These amperometric sensors also yielded currents that tracked venous blood glucose concentrations, showing a clinically acceptable correlation. Studies in people with T1D gave a mean absolute relative difference (MARD) of 9% (with respect to venous blood glucose) with over 94% of the data points in the A and B zones of the Clarke error grid. These findings provide baseline data for further device development and a larger clinical efficacy and acceptability study of this microneedle intradermal glucose sensor in T1D

    Identification of osteopontin as a novel marker for early hepatocellular carcinoma

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    The aim of this study was to identify a biomarker that could improve alpha‐fetoprotein (AFP) performance in hepatocellular carcinoma (HCC) surveillance among patients with cirrhosis. We performed proteomic profiling of plasma from patients with cirrhosis or HCC and validated selected candidate HCC biomarkers in two geographically distinct cohorts to include HCC of different etiologies. Mass spectrometry profiling of highly fractionated plasma from 18 cirrhosis and 17 HCC patients identified osteopontin (OPN) as significantly up‐regulated in HCC cases, compared to cirrhosis controls. OPN levels were subsequently measured in 312 plasma samples collected from 131 HCC patients, 76 cirrhosis patients, 52 chronic hepatitis C (CHC) and B (CHB) patients, and 53 healthy controls in two independent cohorts. OPN plasma levels were significantly elevated in HCC patients, compared to cirrhosis, CHC, CHB, or healthy controls, in both cohorts. OPN alone or in combination with AFP had significantly better area under the receiver operating characteristic curve, compared to AFP, in comparing cirrhosis and HCC in both cohorts. OPN overall performance remained higher than AFP in comparing cirrhosis and the following HCC groups: HCV‐related HCC, HBV‐associated HCC, and early HCC. OPN also had a good sensitivity in AFP‐negative HCC. In a pilot prospective study including 22 patients who developed HCC during follow‐up, OPN was already elevated 1 year before diagnosis. Conclusion : OPN was more sensitive than AFP for the diagnosis of HCC in all studied HCC groups. In addition, OPN performance remained intact in samples collected 1 year before diagnosis. (H EPATOLOGY 2012)Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90204/1/24703_ftp.pd

    First report of Q fever in Oman.

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    Although serologic evidence suggests the presence of Q fever in humans and animals in Saudi Arabia and the United Arab Emirates, acute Q fever has not been reported on the Arabian Peninsula. We report the first two cases of acute Q fever in Oman

    Explaining the effects of an intervention designed to promote evidence-based diabetes care : a theory-based process evaluation of a pragmatic cluster randomised controlled trial

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    Background The results of randomised controlled trials can be usefully illuminated by studies of the processes by which they achieve their effects. The Theory of Planned Behaviour (TPB) offers a framework for conducting such studies. This study used TPB to explore the observed effects in a pragmatic cluster randomised controlled trial of a structured recall and prompting intervention to increase evidence-based diabetes care that was conducted in three Primary Care Trusts in England. Methods All general practitioners and nurses in practices involved in the trial were sent a postal questionnaire at the end of the intervention period, based on the TPB (predictor variables: attitude; subjective norm; perceived behavioural control, or PBC). It focussed on three clinical behaviours recommended in diabetes care: measuring blood pressure; inspecting feet; and prescribing statins. Multivariate analyses of variance and multiple regression analyses were used to explore changes in cognitions and thereby better understand trial effects. Results Fifty-nine general medical practitioners and 53 practice nurses (intervention: n = 55, 41.98% of trial participants; control: n = 57, 38.26% of trial participants) completed the questionnaire. There were no differences between groups in mean scores for attitudes, subjective norms, PBC or intentions. Control group clinicians had 'normatively-driven' intentions (i.e., related to subjective norm scores), whereas intervention group clinicians had 'attitudinally-driven' intentions (i.e., related to attitude scores) for foot inspection and statin prescription. After controlling for effects of the three predictor variables, this group difference was significant for foot inspection behaviour (trial group × attitude interaction, beta = 0.72, p < 0.05; trial group × subjective norm interaction, beta = -0.65, p < 0.05). Conclusion Attitudinally-driven intentions are proposed to be more consistently translated into action than normatively-driven intentions. This proposition was supported by the findings, thus offering an interpretation of the trial effects. This analytic approach demonstrates the potential of the TPB to explain trial effects in terms of different relationships between variables rather than differences in mean scores. This study illustrates the use of theory-based process evaluation to uncover processes underlying change in implementation trials.European Union ReBEQI projec

    Chemically specifi C multiscale modeling of clay-polymer nanocomposites reveals intercalation dynamics, tactoid self-assembly and emergent materials properties

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    A quantitative description is presented of the dynamical process of polymer intercalation into clay tactoids and the ensuing aggregation of polymerentangled tactoids into larger structures, obtaining various characteristics of these nanocomposites, including clay-layer spacings, out-of-plane clay-sheet bending energies, X-ray diffractograms, and materials properties. This model of clay-polymer interactions is based on a three-level approach, which uses quantum mechanical and atomistic descriptions to derive a coarse-grained yet chemically specifi c representation that can resolve processes on hitherto inaccessible length and time scales. The approach is applied to study collections of clay mineral tactoids interacting with two synthetic polymers, poly(ethylene glycol) and poly(vinyl alcohol). The controlled behavior of layered materials in a polymer matrix is centrally important for many engineering and manufacturing applications. This approach opens up a route to computing the properties of complex soft materials based on knowledge of their chemical composition, molecular structure, and processing conditions.This work was funded in part by the EU FP7 MAPPER project (grant number RI-261507) and the Qatar National Research Fund (grant number 09–260–1–048). Supercomputing time was provided by PRACE on JUGENE (project PRA044), the Hartree Centre (Daresbury Laboratory) on BlueJoule and BlueWonder via the CGCLAY project, and on HECToR and ARCHER, the UK national supercomputing facility at the University of Edinburgh, via EPSRC through grants EP/F00521/1, EP/E045111/1, EP/I017763/1 and the UK Consortium on Mesoscopic Engineering Sciences (EP/L00030X/1). The authors are grateful to Professor Julian Evans for stimulating discussions during the course of this project. Data-storage and management services were provided by EUDAT (grant number 283304)
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