ZnO@ZIF-8: Gas sensitive core-shell hetero-structures show reduced cross-sensitivity to humidity

A ‘lawn-like’ distribution of interconnected zinc oxide nanorods, coated with a metal-organic compound based on zeolitic imidazolate frameworks – ZIF-8 was prepared on microstructured thin-film interdigitated Pt-electrodes forming ZnO@ZIF-8 core-shell heterostructures and investigated as gas sensor material in relation to the identical, but uncovered pure ZnO-layer. This composite combines the gas sensing properties of the metal oxide ZnO with the specific properties of the metal-organic framework material which result in a distinct change of the conditions of gas sensing at the ZnO/ZIF-8-interface. Herein, for the first time it is reported that as prepared ZnO@ZIF-8 composite material is an attractive choice to reduce the cross-sensitivity to water vapour (humidity) in the gas sensing response towards propene and ethene. The observed change of sensitivity in relation to uncovered ZnO is discussed to be due to (i) the specific interaction of the ZIF-8 at the interface with the ZnO taking influence on the gas reaction processes, (ii) the diffusivity of ZIF-8 for the different gas components, and (iii) the sorption behaviour of the used gases at the ZnO interface and inside the ZIF-8 material

Ischemic Preconditioning Improves Microvascular Endothelial Function in Remote Vasculature by Enhanced Prostacyclin Production.

BACKGROUND The mechanisms underlying the effect of preconditioning on remote microvasculature remains undisclosed. The primary objective was to document the remote effect of ischemic preconditioning on microvascular function in humans. The secondary objective was to test if exercise also induces remote microvascular effects. METHODS AND RESULTS A total of 12 healthy young men and women participated in 2 experimental days in a random counterbalanced order. On one day the participants underwent 4×5 minutes of forearm ischemic preconditioning, and on the other day they completed 4×5 minutes of hand-grip exercise. On both days, catheters were placed in the brachial and femoral artery and vein for infusion of acetylcholine, sodium nitroprusside, and epoprostenol. Vascular conductance was calculated from blood flow measurements with ultrasound Doppler and arterial and venous blood pressures. Ischemic preconditioning enhanced (P<0.05) the remote vasodilator response to intra-arterial acetylcholine in the leg at 5 and 90 minutes after application. The enhanced response was associated with a 6-fold increase (P<0.05) in femoral venous plasma prostacyclin levels and with a transient increase (P<0.05) in arterial plasma levels of brain-derived neurotrophic factor and vascular endothelial growth factor. In contrast, hand-grip exercise did not influence remote microvascular function. CONCLUSIONS These findings demonstrate that ischemic preconditioning of the forearm improves remote microvascular endothelial function and suggest that one of the underlying mechanisms is a humoral-mediated potentiation of prostacyclin formation

Insulin-induced membrane permeability to glucose in human muscles at rest and following exercise

Running title: Exercise and insulin action on muscle membrane permeability to glucos

Promising outcomes of a national programme for the prevention of mother-to-child HIV transmission in Addis Ababa: a retrospective study

<p>Abstract</p> <p>Background</p> <p>Prevention of Mother-to-Child HIV Transmission (PMTCT) is still the most effective intervention in combating new HIV infections. In 2008, revised national PMTCT guidelines that incorporated new policies on HIV counselling and testing, antiretroviral prophylaxis regimen and infant HIV diagnosis came into effect in Ethiopia. In the present study we have examined trends in PMTCT service utilization and assessed the rate of MTCT in relation to policy changes in the national PMTCT programme.</p> <p>Methods</p> <p>Reports from February 2004 to August 2009 were reviewed in 10 sub-cities in Addis Ababa, Ethiopia. The data was collected from May to October 2009.</p> <p>Results</p> <p>The proportion of women who received HIV counselling and testing among new antenatal care attendees increased from 50.7% (95% CI 50.2-51.2) in 2007 to 84.5% (95% CI 84.1-84.9) in 2009 following the shift to routine opt-out testing. Nevertheless, in 2009 only 53.7% of the positive women and 40.7% of their infants received antiretroviral prophylaxis. The HIV prevalence among antenatal attendees decreased significantly from 10.5% in 2004 to 4.6% in 2009 in parallel to the increased number of women being tested. The HIV positive women were over 18 times (RR 18.5, p < 0.0001) more likely to be referred for treatment, care and support in 2009 than in 2004. The proportion of partners tested for HIV decreased by 14% in 2009 compared to 2004, although the absolute number was increasing year by year. Only 10.6% (95% CI 9.9-11.2) of the HIV positive women completed their follow up to infant HIV testing. The cumulative probability of HIV infection among babies on single dose nevirapine regimen who were tested at >=18 months was 15.0% (95% CI 9.8-22.1) in 2007, whereas it was 8.2% (95% CI 5.55-11.97) among babies on Zidovudine regimen who were tested at >=45 days in 2009.</p> <p>Conclusion</p> <p>The paper demonstrates trends in PMTCT service utilization in relation to changing policy. There is marked improvement in HIV counselling and testing service utilization, especially after the policy shift to routine opt-out testing. However, despite policy changes, the ARV prophylaxis uptake, the loss to follow up and the partner testing have remained unchanged across the years. This should be a matter of immediate concern and a topic for further research.</p

Severe morbidity and mortality in untreated HIV-infected children in a paediatric care programme in Abidjan, Côte d'Ivoire, 2004-2009

<p>Abstract</p> <p>Background</p> <p>Clinical evolution of HIV-infected children who have not yet initiated antiretroviral treatment (ART) is poorly understood in Africa. We describe severe morbidity and mortality of untreated HIV-infected children.</p> <p>Methods</p> <p>All HIV-infected children enrolled from 2004-2009 in a prospective HIV programme in two health facilities in Abidjan, Côte d'Ivoire, were eligible from their time of inclusion. Risks of severe morbidity (the first clinical event leading to death or hospitalisation) and mortality were documented retrospectively and estimated using cumulative incidence functions. Associations with baseline characteristics were assessed by competing risk regression models between outcomes and antiretroviral initiation.</p> <p>Results</p> <p>405 children were included at a median age of 4.5 years; at baseline, 66.9% were receiving cotrimoxazole prophylaxis, and 27.7% met the 2006 WHO criteria for immunodeficiency by age. The risk of developing a severe morbid event was 14% (95%CI: 10.7 - 17.8) at 18 months; this risk was lower in children previously exposed to any prevention of mother-to-child-transmission (PMTCT) intervention (adjusted subdistribution hazard ratio [sHR]: 0.16, 95% CI: 0.04 - 0.71) versus those without known exposure. Cumulative mortality reached 5.5% (95%CI: 3.5 - 8.1) at 18 months. Mortality was associated with immunodeficiency (sHR: 6.02, 95% CI: 1.28-28.42).</p> <p>Conclusions</p> <p>Having benefited from early access to care minimizes the severe morbidity risk for children who acquire HIV. Despite the receipt of cotrimoxazole prophylaxis, the risk of severe morbidity and mortality remains high in untreated HIV-infected children. Such evidence adds arguments to promote earlier access to ART in HIV-infected children in Africa and improve care interventions in a context where treatment is still not available to all.</p

Male partner attendance of skilled antenatal care in peri-urban Gulu district, Northern Uganda

<p>Abstract</p> <p>Background</p> <p>Male partner attendance of skilled Antenatal Care (ANC) is beneficial to improving maternal outcomes. This study investigated the level, perceived benefits and factors associated with male partner attendance of skilled ANC in a peri-urban community recovering from two decades of civil conflict.</p> <p>Methods</p> <p>This cross-sectional survey used multi-stage sampling in 12 villages of Omoro county to select 331 married male respondents aged 18 years or more, whose female spouses had childbirth within 24 months prior to the survey. A structured questionnaire elicited responses about male partner attendance of ANC during pregnancy at a public health facility as the main outcome variable. Analysis used Generalized Linear Model (GLM) in Stata version 10.0 to obtain Prevalence Risk Ratios (PRR) for association between the binary outcome and independent factors. All factors significant at p < 0.15 and potential confounders were included in the multivariable model.</p> <p>Results</p> <p>Overall, 65.4% (95%CI; 60.3, 70.5) male partners attended at least one skilled ANC visit. Mean age was 31.9 years [SD 8.2]. Perceived benefits of attending ANC were: HIV screening (74.5%), monitoring foetal growth (34%) and identifying complications during pregnancy (18.9%). Factors independently associated with higher ANC attendance were: knowledge of 3 or more ANC services (adj.PRR 2.77; 95%CI 2.24, 3.42), obtaining health information from facility health workers (adj.PRR 1.14; 95%CI 1.01, 1.29) and if spouse had skilled attendance at last childbirth (adj.PRR 1.31; 95%CI 1.04-1.64). However, factors for low attendance were: male partners intending their spouse to carry another pregnancy (adj.PRR 0.83; 95%CI 0.71, 0.97) and living more than 5 Km from a health facility (adj.PRR 0.83, 95%CI 0.70, 0.98).</p> <p>Conclusions</p> <p>Men who were knowledgeable of ANC services, obtained health information from a health worker and whose spouses utilised skilled delivery at last pregnancy were more likely to accompany their spouses at ANC, unlike those who wanted to have more children and lived more than 5 km from the health facility. These findings suggest that empowering male partners with knowledge about ANC services may increase their ANC participation and in turn increase skilled delivery. This strategy may improve maternal health care in post conflict and resource-limited settings.</p