360 research outputs found

    Importance of tetrahedral coordination for high-valent transition metal oxides: YCrO4_4 as a model system

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    We have investigated the electronic structure of the high oxidation state material YCrO4_4 within the framework of the Zaanen-Sawatzky-Allen phase diagram. While Cr4+^{4+}-based compounds like SrCrO3_3/CaCrO3_3 and CrO2_2 can be classified as small-gap or metallic negative-charge-transfer systems, we find using photoelectron spectroscopy that YCrO4_4 is a robust insulator despite the fact that its Cr ions have an even higher formal valence state of 5+. We reveal using band structure calculations that the tetrahedral coordination of the Cr5+^{5+} ions in YCrO4_4 plays a decisive role, namely to diminish the bonding of the Cr 3d3d states with the top of the O 2p2p valence band. This finding not only explains why the charge-transfer energy remains effectively positive and the material stable, but also opens up a new route to create doped carriers with symmetries different from those of other transition-metal ions.Comment: 6 pages, 6 figure

    Outcomes of the South African National Antiretroviral Treatment Programme for children: The IeDEA Southern Africa collaboration

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    Objectives. To assess paediatric antiretroviral treatment (ART)outcomes and their associations from a collaborative cohortrepresenting 20% of the South African national treatment programme.Design and setting. Multi-cohort study of 7 public sectorpaediatric ART programmes in Gauteng, Western Cape andKwaZulu-Natal provinces. Subjects. ART-naive children (.16 years) who commenced treatment with .3 antiretroviral drugs before March 2008.Outcome measures. Time to death or loss to follow-up were assessed using the Kaplan-Meier method. Associations between baseline characteristics and mortality were assessed with Cox proportional hazards models stratified by site. Immune status, virological suppression and growth were described in relation to duration of ART.Results. The median (interquartile range) age of 6 078 childrenwith 9 368 child-years of follow-up was 43 (15 - 83) months, with 29% bein

    Breast Milk Macronutrients in Relation to Infants’ Anthropometric Measures

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    BACKGROUND: Breast milk (BM) is the main nutritional source for newborns before they are capable to eat and consume other foods. BM has carbohydrates, lipids, complex proteins, and other biologically active components which have a direct effect on infant growth. AIM: The aim of the study was to correlate anthropometric data of the infant to macronutrients in BM (fat, protein, and carbohydrates) and to find some modifiable issues affecting macronutrient contents of BM for the benefits of upcoming infants. METHODS: One hundred breastfeeding mothers participated in the study, they were recruited from the outpatient clinic, El Demerdash Hospital, Ain Shams University, from September 2019, to December 2019. BM was expressed by an electric pump, macronutrient content was assessed. Anthropometric data of the babies and mothers were obtained, gestational age, parity, age of the women, and the route of birth were recorded. RESULTS: For the macronutrients content of milk, a positive significant correlation was observed between BM fat, protein, and lactose. Infants’ body mass index (BMI) was negatively related to the fat content of BM, while no relation was found between BMI and protein or lactose content of the milk. BM fat content was negatively correlated with gestational age and maternal age. Positive correlations were found between BMI and protein, lactose and infant age. Protein content was negatively correlated with parity. No impact of infant’s sex on BM composition and as regards maternal diet, high protein consumption leading to increase BM protein content. CONCLUSIONS: The current study confirms that BM macronutrient composition has a wide variability; this variability is associated with each macronutrient, respectively. To improve BM composition, one could aim for improving the nutritional balance in lactating women, especially for protein intake. More well-designed longitudinal studies about factors that influence human milk compositions are warranted

    Monitoring the South African National Antiretroviral Treatment Programme, 2003 - 2007: The IeDEA Southern Africa collaboration

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    Objectives. To introduce the combined South African cohortsof the International epidemiologic Databases to EvaluateAIDS Southern Africa (IeDEA-SA) collaboration as reflectingthe South African national antiretroviral treatment (ART)programme; to characterise patients accessing these services;and to describe changes in services and patients from 2003 to2007.Design and setting. Multi-cohort study of 11 ART programmesin Gauteng, Western Cape, Free State and KwaZulu-Natal.Subjects. Adults and children

    Characterizing the double-sided cascade of care for adolescents living with HIV transitioning to adulthood across Southern Africa

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    INTRODUCTION: As adolescents and young people living with HIV (AYLH) age, they face a "transition cascade," a series of steps associated with transitions in their care as they become responsible for their own healthcare. In high-income countries, this usually includes transfer from predominantly paediatric/adolescent to adult clinics. In sub-Saharan Africa, paediatric HIV care is mostly provided in decentralized, non-specialist primary care clinics, where "transition" may not necessarily include transfer of care but entails becoming more autonomous for one's HIV care. Using different age thresholds as proxies for when "transition" to autonomy might occur, we evaluated pre- and post-transition outcomes among AYLH. METHODS: We included AYLH aged <16 years at enrolment, receiving antiretroviral therapy (ART) within International epidemiology Databases to Evaluate AIDS Southern Africa (IeDEA-SA) sites (2004 to 2017) with no history of transferring care. Using the ages of 16, 18, 20 and 22 years as proxies for "transition to autonomy," we compared the outcomes: no gap in care (≥2 clinic visits) and viral suppression (HIV-RNA <400 copies/mL) in the 12 months before and after each age threshold. Using log-binomial regression, we examined factors associated with no gap in care (retention) in the 12 months post-transition. RESULTS: A total of 5516 AYLH from 16 sites were included at "transition" age 16 (transition-16y), 3864 at 18 (transition-18y), 1463 at 20 (transition-20y) and 440 at 22 years (transition-22y). At transition-18y, in the 12 months pre- and post-transition, 83% versus 74% of AYLH had no gap in care (difference 9.3 (95% confidence interval (CI) 7.8 to 10.9)); while 65% versus 62% were virally suppressed (difference 2.7 (-1.0 to 6.5%)). The strongest predictor of being retained post-transition was having no gap in the preceding year, across all transition age thresholds (transition-16y: adjusted risk ratio (aRR) 1.72; 95% CI (1.60 to 1.86); transition-18y: aRR 1.76 (1.61 to 1.92); transition-20y: aRR 1.75 (1.53 to 2.01); transition-22y: aRR 1.47; (1.21 to 1.78)). CONCLUSIONS: AYLH with gaps in care need targeted support to prevent non-retention as they take on greater responsibility for their healthcare. Interventions to increase virologic suppression rates are necessary for all AYLH ageing to adulthood

    Outcomes of the South African National Antiretroviral Treatment Programme for children: The IeDEA Southern Africa collaboration

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    Objectives: To assess paediatric antiretroviral treatment (ART) outcomes and their associations from a collaborative cohort representing 20% of the South African national treatment programme. Design and setting: Multi-cohort study of 7 public sector paediatric ART programmes in Gauteng, Western Cape and KwaZulu-Natal provinces. Subjects: ART-naïve children (≤16 years) who commenced treatment with ≥3 antiretroviral drugs before March 2008. Outcome measures: Time to death or loss to follow-up were assessed using the Kaplan-Meier method. Associations between baseline characteristics and mortality were assessed with Cox-proportional hazards models stratified by site. Immune status, virologic suppression and growth were also described by duration on ART. Results: The median (IQR) age of 6078 children with 9368 child-years of follow-up was 43 (15 – 83) months, with 29% being <18 months. Most were severely ill at ART initiation. More than 75% of children were appropriately monitored at 6-monthly intervals with viral load suppression (<400 copies/ml) being 80% or above throughout 36 months of treatment. Mortality and retention in care at 3 years were 7.7% (95%CI: 7.0% – 8.6%) and 81.4% (80.1% - 82.6%) respectively. Together with young age, all markers of disease severity (low weight-for-age z-score; high viral load; severe immune suppression, stage 3/4 disease and anaemia) were independently associated with mortality. Conclusions: Dramatic clinical benefit for children accessing the national ART programme is demonstrated. Higher mortality in infants and those with advanced disease highlights the need for early diagnosis of HIV infection and commencement of ART

    Recent Trends in Development of High Voltage Circuit Breakers with SF6 Alternative Gases

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    The available knowledge of state-of-the-art of SF6 alternative gases in switching applications was collected and evaluated in an initiative of the Current Zero Club together with CIGRE. The present contribution summarizes the main results of this activity and will also include the latest trends. The main properties and switching performance of new gases are compared to SF6. The most promising new gases are at the moment perfluoroketones and perfluoronitriles. Due to the high boiling point of these gases, in HV applications mixtures with CO2 are used. For MV insulation perfluoroketones are mixed with air, but also other combinations might be possible. The dielectric and switching performance of the mixtures, with mixing ratios that allow sufficiently low operating temperatures, is reported to be only slightly below SF6. Minor design changes or de-rating of switchgear are therefore necessary. Differences between the gas mixtures are mainly in the boiling point and the GWP

    Immune reconstitution inflammatory syndrome presenting as chylothorax in a patient with HIV and Mycobacterium tuberculosis coinfection: a case report

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    <p>Abstract</p> <p>Background</p> <p>Patients with human immunodeficiency virus (HIV) infection are at risk for <it>Mycobacterium tuberculosis </it>(TB) coinfection. The advent of antiretroviral therapy restores immunity in HIV-infected patients, but predisposes patients to immune reconstitution inflammatory syndrome (IRIS).</p> <p>Case Presentation</p> <p>A 25-year-old HIV-infected male presented with fever, productive cough, and body weight loss for 2 months. His CD4 cell count was 11 cells/μl and HIV-1 viral load was 315,939 copies/ml. Antituberculosis therapy was initiated after the diagnosis of pulmonary TB. One week after antituberculosis therapy, antiretroviral therapy was started. However, multiple mediastinal lymphadenopathies and chylothorax developed. Adequate drainage of the chylothorax, suspension of antiretroviral therapy, and continued antituberculosis therapy resulted in successful treatment and good outcome.</p> <p>Conclusions</p> <p>Chylothorax is a rare manifestation of TB-associated IRIS in HIV-infected patients. Careful monitoring for development of IRIS during treatment of HIV-TB coinfection is essential to minimize the associated morbidity and mortality.</p

    Local correlations in the 1D Bose gas from a scaling limit of the XXZ chain

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    We consider the K-body local correlations in the (repulsive) 1D Bose gas for general K, both at finite size and in the thermodynamic limit. Concerning the latter we develop a multiple integral formula which applies for arbitrary states of the system with a smooth distribution of Bethe roots, including the ground state and finite temperature Gibbs-states. In the cases K<=4 we perform the explicit factorization of the multiple integral. In the case of K=3 we obtain the recent result of Kormos et.al., whereas our formula for K=4 is new. Numerical results are presented as well.Comment: 23 pages, 2 figures, v2: minor modifications and references adde
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