626 research outputs found
A new approach to calculate the gluon polarization
We derive the Leading-Order master equation to extract the polarized gluon
distribution G(x;Q^2) = x \deltag(x;Q^2) from polarized proton structure
function, g1p(x;Q^2). By using a Laplace-transform technique, we solve the
master equation and derive the polarized gluon distribution inside the proton.
The test of accuracy which are based on our calculations with two different
methods confirms that we achieve to the correct solution for the polarized
gluon distribution. We show that accurate experimental knowledge of g1p(x;Q^2)
in a region of Bjorken x and Q^2, is all that is needed to determine the
polarized gluon distribution in that region. Therefore, to determine the gluon
polarization \deltag /g,we only need to have accurate experimental data on
un-polarized and polarized structure functions (F2p (x;Q^2) and g1p(x;Q^2)).Comment: 12 pages, 5 figure
Clinical use of HIV integrase inhibitors : a systematic review and meta-analysis
Background: Optimal regimen choice of antiretroviral therapy is essential to achieve long-term clinical success. Integrase inhibitors have swiftly been adopted as part of current antiretroviral regimens. The purpose of this study was to review the evidence for integrase inhibitor use in clinical settings.
Methods: MEDLINE and Web-of-Science were screened from April 2006 until November 2012, as were hand-searched scientific meeting proceedings. Multiple reviewers independently screened 1323 citations in duplicate to identify randomized controlled trials, nonrandomized controlled trials and cohort studies on integrase inhibitor use in clinical practice. Independent, duplicate data extraction and quality assessment were conducted.
Results: 48 unique studies were included on the use of integrase inhibitors in antiretroviral therapy-naive patients and treatment-experienced patients with either virological failure or switching to integrase inhibitors while virologically suppressed. On the selected studies with comparable outcome measures and indication (n = 16), a meta-analysis was performed based on modified intention-to-treat (mITT), on-treatment (OT) and as-treated (AT) virological outcome data. In therapy-naive patients, favorable odds ratios (OR) for integrase inhibitor-based regimens were observed, (mITT OR 0.71, 95% CI 0.59-0.86). However, integrase inhibitors combined with protease inhibitors only did not result in a significant better virological outcome. Evidence further supported integrase inhibitor use following virological failure (mITT OR 0.27; 95% CI 0.11-0.66), but switching to integrase inhibitors from a high genetic barrier drug during successful treatment was not supported (mITT OR 1.43; 95% CI 0.89-2.31). Integrase inhibitor-based regimens result in similar immunological responses compared to other regimens. A low genetic barrier to drug-resistance development was observed for raltegravir and elvitegravir, but not for dolutegravir.
Conclusion: In first-line therapy, integrase inhibitors are superior to other regimens. Integrase inhibitor use after virological failure is supported as well by the meta-analysis. Careful use is however warranted when replacing a high genetic barrier drug in treatment-experienced patients switching successful treatment
Week 96 efficacy and safety results of the phase 3, randomized EMERALD trial to evaluate switching from boosted-protease inhibitors plus emtricitabine/tenofovir disoproxil fumarate regimens to the once daily, single-tablet regimen of darunavir/cobicistat/emtricitabine/tenofovir alafenamide (D/C/F/TAF) in treatment-experienced, virologically-suppressed adults living with HIV-1
Darunavir/cobicistat/emtricitabine/tenofovir alafenamide (D/C/F/TAF) 800/150/200/10 mg was investigated through 96 weeks in EMERALD (NCT02269917).
Virologically-suppressed, HIV-1-positive treatment-experienced adults (previous non-darunavir virologic failure [VF] allowed) were randomized (2:1) to D/C/F/TAF or boosted protease inhibitor (PI) plus emtricitabine/tenofovir-disoproxil-fumarate (F/TDF) over 48 weeks. At week 52 participants in the boosted PI arm were offered switch to D/C/F/TAF (late-switch, 44 weeks D/C/F/TAF exposure). All participants were followed on D/C/F/TAF until week 96. Efficacy endpoints were percentage cumulative protocol-defined virologic rebound (PDVR; confirmed viral load [VL] >= 50 copies/mL) and VL = 50 copies/mL (VF) (FDA-snapshot analysis).
Of 1141 randomized patients, 1080 continued in the extension phase. Few patients had PDVR (D/C/F/TAF: 3.1%, 24/763 cumulative through week 96; late-switch: 2.3%, 8/352 week 52-96). Week 96 virologic suppression was 90.7% (692/763) (D/C/F/TAF) and 93.8% (330/352) (late-switch). VF was 1.2% and 1.7%, respectively. No darunavir, primary PI, tenofovir or emtricitabine resistance-associated mutations were observed post-baseline. No patients discontinued for efficacy-related reasons. Few discontinued due to adverse events (2% D/C/F/TAF arm). Improved renal and bone parameters were maintained in the D/C/F/TAF arm and observed in the late-switch arm, with small increases in total cholesterol/high-density-lipoprotein-cholesterol ratio. A study limitation was the lack of a control arm in the week 96 analysis.
Through 96 weeks, D/C/F/TAF resulted in low PDVR rates, high virologic suppression rates, very few VFs, and no resistance development. Late-switch results were consistent with D/C/F/TAF week 48 results. EMERALD week 96 results confirm the efficacy, high genetic barrier to resistance and safety benefits of D/C/F/TAF
Risk Factors for Hepatitis C Virus Transmission to Health Care Workers after Occupational Exposure: A European Case-Control Study
Background. Additional studies are required to identify risk factors for hepatitis C virus (HCV) transmission to health care workers after occupational exposure to HCV. Methods. We conducted a matched case-control study in 5 European countries from 1 January 1991 through 31 December 2002. Case patients were health care workers who experienced seroconversion after percutaneous or mucocutaneous exposure to HCV. Control subjects were HCV-exposed health care workers who did not experience seroconversion and were matched with case patients for center and period of exposure. Results. Sixty case patients and 204 control subjects were included in the study. All case patients were exposed to HCV-infected fluids through percutaneous injuries. The 37 case patients for whom information was available were exposed to viremic source patients. As risk factors for HCV infection, multivariate analysis identified needle placement in a source patient's vein or artery (odds ratio [OR], 100.1; 95% confidence interval [CI], 7.3-1365.7), deep injury (OR, 155.2; 95% CI, 7.1-3417.2), and sex of the health care worker (OR for male vs. female, 3.1; 95% CI, 1.0-10.0). Source patient HCV load was not introduced in the multivariate model. In unmatched univariate analysis, the risk of HCV transmission increased 11-fold for health care workers exposed to source patients with a viral load >6 log10 copies/mL (95% CI, 1.1-114.1), compared with exposures to source patients with a viral load ⩽4 log10 copies/mL. Conclusion. In this study, HCV occupational transmission was found to occur after percutaneous exposures. The risk of HCV transmission after percutaneous exposure increased with deep injuries and procedures involving hollow-bore needle placement in the source patient's vein or artery. These results highlight the need for widespread adoption of needlestick-prevention devices in health care settings, together with other preventive measure
Engaging new migrants in infectious disease screening: a qualitative semi-structured interview study of UK migrant community health-care leads.
Migration to Europe - and in particular the UK - has risen dramatically in the past decades, with implications for public health services. Migrants have increased vulnerability to infectious diseases (70% of TB cases and 60% HIV cases are in migrants) and face multiple barriers to healthcare. There is currently considerable debate as to the optimum approach to infectious disease screening in this often hard-to-reach group, and an urgent need for innovative approaches. Little research has focused on the specific experience of new migrants, nor sought their views on ways forward. We undertook a qualitative semi-structured interview study of migrant community health-care leads representing dominant new migrant groups in London, UK, to explore their views around barriers to screening, acceptability of screening, and innovative approaches to screening for four key diseases (HIV, TB, hepatitis B, and hepatitis C). Participants unanimously agreed that current screening models are not perceived to be widely accessible to new migrant communities. Dominant barriers that discourage uptake of screening include disease-related stigma present in their own communities and services being perceived as non-migrant friendly. New migrants are likely to be disproportionately affected by these barriers, with implications for health status. Screening is certainly acceptable to new migrants, however, services need to be developed to become more community-based, proactive, and to work more closely with community organisations; findings that mirror the views of migrants and health-care providers in Europe and internationally. Awareness raising about the benefits of screening within new migrant communities is critical. One innovative approach proposed by participants is a community-based package of health screening combining all key diseases into one general health check-up, to lessen the associated stigma. Further research is needed to develop evidence-based community-focused screening models - drawing on models of best practice from other countries receiving high numbers of migrants
CLC, a promising concept with challenging development issues
Chemical Looping Combustion (CLC) is a promising technique to achieve fuel combustion in a nitrogen free atmosphere, therefore giving the possibility to separate and store or use CO2. Several potential applications are considered in the field of power generation with gas, liquid and solid fuels. In the Carbon Capture, Storage and Utilization (CCSU) context, energy penalty is reduced compared to other routes. In addition, other applications of Chemical Looping are considered in the field of H2 production or gasification for instance.
In the past years, a huge effort has been conducted worldwide to investigate CLC materials and process issues. In 2008, IFPEN and Total have started an ambitious collaboration to develop CLC applications. Nowadays, the CLC concept is well demonstrated at the pilot scale. The next step is to demonstrate the technology over time at larger scale. However, for further developments, the challenges are numerous and will be discussed, both on market and technical aspects. Short term market is limited. Uncertainties around CO2 emission market and storage issues are related to CO2 policy and public acceptance of storage which still must evolve in the right direction... Financing of demonstration units in this context is challenging and other applications of CLC have to be investigated. The industrial use of synthetic metal oxides or natural ores at large scale generates a lot of issues related to availability, price, waste disposal, health and safety, additionally to chemical and mechanical stability over time, reactivity, and oxygen transfer capacity. Chemical looping reactor and process technology concepts have to be explored, developed, modeled and scaled-up in order to ensure adequate power production together with good gas solid contact and reaction requirement, controlled circulation of mixtures of particle (oxygen carrier, ash, solid fuel for instance). All these points should be considered at very large scale for CCS applications in order to minimize energy penalty and cost in severe operating conditions (temperatures above 800°C and intense solid circulation).
Technical challenges remain to be solved and proven with large demonstration over long periods of time. In this context, research in the field of fluidization technology is essential and we will address a couple of key points already investigated at IFPEN and related to control of solid circulation, oxygen carrier attrition, conceptual design of CLC reactors and process performance
Some at Risk for COVID-19 Are Reluctant to Take Precautions, but Others Are Not: A Case from Rural Iran
Little is known about the evaluative and cognitive foundations for adopting preventive measures to reduce the spread of COVID-19. Recognizing the existence of a gap in the knowledge describing the intention and behavior of participating in health measures, this study investigated the drivers that contribute to the intention to take health protective measures among 305 rural youth from the Dashtestan Region, Bushehr Province, southwestern Iran, reached through an online survey. Protection motivation theory (PMT) served as the theoretical framework for the study. It was able to forecast variation in intentions and behaviors with accuracies of 39% and 64%, respectively. Furthermore, the variables of response efficiency, perceived severity, and self-efficacy had a positive and significant effect on protective intentions. Additionally, perceived severity, self-efficacy, and intention produced a positive and significant impression on behaviors, with most of the behavioral variance being accounted for by the intention, as was hypothesized. In conclusion, it is suggested that health development including training measures that take account of both the concrete issues of health resources and technologies and of more abstract ones, such as mindset readiness, are important for engagement in positive health care behaviors. Accordingly, training-based interventions for rural youth should be contemplated, with the object of changing their intentions
Sex-specific genetic effects influence variation in body composition
Aims/hypothesis: Despite well-known sex differences in body composition it is not known whether sex-specific genetic or environmental effects contribute to these differences. Methods: We assessed body composition in 2,506 individuals, from a young Dutch genetic isolate participating in the Erasmus Rucphen Family study, by dual-energy X-ray absorptiometry and anthropometry. We used variance decomposition procedures to partition variation of body composition into genetic and environmental components common to both sexes and to men and women separately and calculated the correlation between genetic components in men and women. Results: After accounting for age
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