122 research outputs found

    A Comparative Study of Vector Control and Model Predictive Control Technique for Grid Connected Battery System

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    Advancements made to battery energy storage technologies have led to increasing integration of battery systems with the grid. This paper presents a comparative study of the well-established vector control technique and the model predictive current control technique as applied to the grid connected battery systems. An electrical equivalent model of the battery is modeled and integrated with the grid using a three- phase bidirectional converter. The comparative study is shown for bidirectional flow of power to charge/discharge the battery from the grid. Also, the effects of model predictive control versus vector control technique are analyzed at an event of grid fault. Asymmetrical and symmetrical grid fault is considered for the comparison. All the modeling and simulation is performed in PSCADTM/EMTDCTM. The results are plotted using MATLAB R2017a. The results show that the model predictive control technique performs as good as the vector control technique for a battery connected grid system

    Prevalence of sickle cell trait and needs assessment for uptake of sickle cell screening among secondary school students in Kampala City, Uganda

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    Background Sickle cell disease (SCD) is one of the most frequent and traumatizing genetic disease in Uganda, with the prevalence of the sickle cell trait (SCT) estimated at 13.3% leading to serious psycho-social and economic impact on the patients and their families. Aim This study aimed to determine the burden of SCT and factors influencing the uptake of screening services among secondary school students in Uganda. Methods We used an analytical cross-sectional design with a multi-stage sampling approach. A total of 399 students from four secondary schools in Kampala City were enrolled in this study. Data were gathered using semi-structured questionnaires and blood screening. We used the sickling test to determine the presence of sickle cell alleles among the participants and hemoglobin electrophoresis as a confirmatory test. Data gathered using the questionnaire were analyzed using descriptive and inferential statistics. Results In total, 5.8% of participants who were tested during this study had SCT. Most (80.2%) participants were not in an intimate relationship at the time of data collection. The majority (60.4%) had moderate knowledge about SCT screening and obtained information about screening from the school. Only 29 (7.3%) participants knew of a family member with sickle cell. Overall, participants had a negative attitude toward SCT screening (67%), although 41.6% believed that most people who were sickle cell carriers did not live long and were often sick. Statistically significant associations were found between testing for SCT and knowing a partner’s sickle cell status (odds ratio [OR] 2.112, p = 0.043) and Anglican religion (OR 2.075, p = 0.047). Conclusion Despite the moderate level of knowledge and negative attitudes, a relatively large number of participants had SCT. This highlights the need for a comprehensive health education package targeting adolescents to promote SCD/SCT screening

    One-arm safety intervention study on community case management of chest indrawing pneumonia in children in Nigeria - a study protocol.

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    Current recommendations within integrated community case management (iCCM) programmes advise community health workers (CHWs) to refer cases of chest indrawing pneumonia to health facilities for treatment, but many children die due to delays or non-compliance with referral advice. Recent revision of World Health Organization (WHO) pneumonia guidelines and integrated management of childhood illness chart booklet recommend oral amoxicillin for treatment of lower chest indrawing (LCI) pneumonia on an outpatient basis. However, these guidelines did not recommend its use by CHWs as part of iCCM, due to insufficient evidence regarding safety. We present a protocol for a one-arm safety intervention study aimed at increasing access to treatment of pneumonia by training CHWs, locally referred to as Community Oriented Resource Persons (CORPs) in Nigeria. The primary objective was to assess if CORPs could safely and appropriately manage LCI pneumonia in 2-59 month old children, and refer children with danger signs. The primary outcomes were the proportion of children 2-59 months with LCI pneumonia who were managed appropriately by CORPs and the clinical treatment failure within 6 days of LCI pneumonia. Secondary outcomes included proportion of children with LCI followed up by CORPs on day 3; caregiver adherence to treatment for chest indrawing, acceptability and satisfaction of both CORP and caregivers on the mode of treatment, including caregiver adherence to treatment; and clinical relapse of pneumonia between day 7 to 14 among children whose signs of pneumonia disappeared by day 6. Approximately 308 children 2-59 months of age with LCI pneumonia would be needed for this safety intervention study

    The health seeking behaviour of elderly population in a poor-urban community of Karachi, Pakistan

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    OBJECTIVES: To presents socio-demographic characteristics and health seeking behaviour of elderly and to determine frequency of Diabetes Mellitus and Hypertension in elderly population of a poor peri-urban community in Karachi, Pakistan. METHODS: A cross-sectional study was conducted, targeting population aged 65 or above. A total of 438 respondents were interviewed after taking informed consent, between November 2005 and December 2005. Frequencies and Chi square values were calculated for different variables using SPSS 13.0. RESULTS: Total population surveyed comprised of 438 elderly, 158 (36%) women and 280 (63.9%) men. Mean age for the population was 71.44 +/- 7.74. A total of 238 (54.3%) elderly were found to be economically active. More than half (n = 269, 61.4%) of the elderly were found to be illiterate. Only 72 (16.4%) of the elderly population were Diabetic and 132 (30.1%) were Hypertensive. Common symptoms that prompted elderly of Azam Basti to seek health care were fever (61.2%), generalized body aches (43.4%) and cough (40.4%). Over half of the (n = 269, 61.4%) responders reported factors which deterred them from seeking health care, out of which 62% reported financial constraint as the commonest factor. Deterrence from seeking health care was associated with illiteracy (p = 0.001) and living alone (p = 0.06). CONCLUSION: The elderly population of this peri-urban community has financial constraints in seeking health care. Hypertension was found to be more prevalent among women as compared to men, ratio being 1:2. Less number of people knew they were diabetics; this might be attributed to ignorance and non-availability of investigations and screening

    Mitochondrial Ca(2+) uptake by the voltage-dependent anion channel 2 regulates cardiac rhythmicity.

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    Tightly regulated Ca(2+) homeostasis is a prerequisite for proper cardiac function. To dissect the regulatory network of cardiac Ca(2+) handling, we performed a chemical suppressor screen on zebrafish tremblor embryos, which suffer from Ca(2+) extrusion defects. Efsevin was identified based on its potent activity to restore coordinated contractions in tremblor. We show that efsevin binds to VDAC2, potentiates mitochondrial Ca(2+) uptake and accelerates the transfer of Ca(2+) from intracellular stores into mitochondria. In cardiomyocytes, efsevin restricts the temporal and spatial boundaries of Ca(2+) sparks and thereby inhibits Ca(2+) overload-induced erratic Ca(2+) waves and irregular contractions. We further show that overexpression of VDAC2 recapitulates the suppressive effect of efsevin on tremblor embryos whereas VDAC2 deficiency attenuates efsevin\u27s rescue effect and that VDAC2 functions synergistically with MCU to suppress cardiac fibrillation in tremblor. Together, these findings demonstrate a critical modulatory role for VDAC2-dependent mitochondrial Ca(2+) uptake in the regulation of cardiac rhythmicity

    Treatment of neonatal infections: a multi-country analysis of health system bottlenecks and potential solutions.

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    BACKGROUND: Around one-third of the world's 2.8 million neonatal deaths are caused by infections. Most of these deaths are preventable, but occur due to delays in care-seeking, and access to effective antibiotic treatment with supportive care. Understanding variation in health system bottlenecks to scale-up of case management of neonatal infections and identifying solutions is essential to reduce mortality, and also morbidity. METHODS: A standardised bottleneck analysis tool was applied in 12 countries in Africa and Asia as part of the development of the Every Newborn Action Plan. Country workshops involved technical experts to complete a survey tool, to grade health system "bottlenecks" hindering scale up of maternal-newborn intervention packages. Quantitative and qualitative methods were used to analyse the data, combined with literature review, to present priority bottlenecks and synthesise actions to improve case management of newborn infections. RESULTS: For neonatal infections, the health system building blocks most frequently graded as major or significant bottlenecks, irrespective of mortality context and geographical region, were health workforce (11 out of 12 countries), and community ownership and partnership (11 out of 12 countries). Lack of data to inform decision making, and limited funding to increase access to quality neonatal care were also major challenges. CONCLUSIONS: Rapid recognition of possible serious bacterial infection and access to care is essential. Inpatient hospital care remains the first line of treatment for neonatal infections. In situations where referral is not possible, the use of simplified antibiotic regimens for outpatient management for non-critically ill young infants has recently been reported in large clinical trials; WHO is developing a guideline to treat this group of young infants. Improving quality of care through more investment in the health workforce at all levels of care is critical, in addition to ensuring development and dissemination of national guidelines. Improved information systems are needed to track coverage and adequately manage drug supply logistics for improved health outcomes. It is important to increase community ownership and partnership, for example through involvement of community groups

    A Multicenter Evaluation of Vancomycin-Associated Acute Kidney Injury in Hospitalized Patients with Acute Bacterial Skin and Skin Structure Infections

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    BACKGROUND: We sought to determine the real-world incidence of and risk factors for vancomycin-associated acute kidney injury (V-AKI) in hospitalized adults with acute bacterial skin and skin structure infections (ABSSSI). METHODS: Retrospective, observational, cohort study at ten U.S. medical centers between 2015 and 2019. Hospitalized patients treated with vancomycin (≥ 72 h) for ABSSSI and ≥ one baseline AKI risk factor were eligible. Patients with end-stage kidney disease, on renal replacement therapy or AKI at baseline, were excluded. The primary outcome was V-AKI by the vancomycin guidelines criteria. RESULTS: In total, 415 patients were included. V-AKI occurred in 39 (9.4%) patients. Independent risk factors for V-AKI were: chronic alcohol abuse (aOR 4.710, 95% CI 1.929-11.499), no medical insurance (aOR 3.451, 95% CI 1.310-9.090), ICU residence (aOR 4.398, 95% CI 1.676-11.541), Gram-negative coverage (aOR 2.926, 95% CI 1.158-7.392) and vancomycin duration (aOR 1.143, 95% CI 1.037-1.260). Based on infection severity and comorbidities, 34.7% of patients were candidates for oral antibiotics at baseline and 39.3% had non-purulent cellulitis which could have been more appropriately treated with a beta-lactam. Patients with V-AKI had significantly longer hospital lengths of stay (9 vs. 6 days, p = 0.001), higher 30-day readmission rates (30.8 vs. 9.0%, p \u3c 0.001) and increased all-cause 30-day mortality (5.1 vs. 0.3%, p = 0.024) CONCLUSIONS: V-AKI occurred in approximately one in ten ABSSSI patients and may be largely prevented by preferential use of oral antibiotics whenever possible, using beta-lactams for non-purulent cellulitis and limiting durations of vancomycin therapy

    Count every newborn; a measurement improvement roadmap for coverage data.

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    BACKGROUND: The Every Newborn Action Plan (ENAP), launched in 2014, aims to end preventable newborn deaths and stillbirths, with national targets of ≤12 neonatal deaths per 1000 live births and ≤12 stillbirths per 1000 total births by 2030. This requires ambitious improvement of the data on care at birth and of small and sick newborns, particularly to track coverage, quality and equity. METHODS: In a multistage process, a matrix of 70 indicators were assessed by the Every Newborn steering group. Indicators were graded based on their availability and importance to ENAP, resulting in 10 core and 10 additional indicators. A consultation process was undertaken to assess the status of each ENAP core indicator definition, data availability and measurement feasibility. Coverage indicators for the specific ENAP treatment interventions were assigned task teams and given priority as they were identified as requiring the most technical work. Consultations were held throughout. RESULTS: ENAP published 10 core indicators plus 10 additional indicators. Three core impact indicators (neonatal mortality rate, maternal mortality ratio, stillbirth rate) are well defined, with future efforts needed to focus on improving data quantity and quality. Three core indicators on coverage of care for all mothers and newborns (intrapartum/skilled birth attendance, early postnatal care, essential newborn care) have defined contact points, but gaps exist in measuring content and quality of the interventions. Four core (antenatal corticosteroids, neonatal resuscitation, treatment of serious neonatal infections, kangaroo mother care) and one additional coverage indicator for newborns at risk or with complications (chlorhexidine cord cleansing) lack indicator definitions or data, especially for denominators (population in need). To address these gaps, feasible coverage indicator definitions are presented for validity testing. Measurable process indicators to help monitor health service readiness are also presented. A major measurement gap exists to monitor care of small and sick babies, yet signal functions could be tracked similarly to emergency obstetric care. CONCLUSIONS: The ENAP Measurement Improvement Roadmap (2015-2020) outlines tools to be developed (e.g., improved birth and death registration, audit, and minimum perinatal dataset) and actions to test, validate and institutionalise proposed coverage indicators. The roadmap presents a unique opportunity to strengthen routine health information systems, crosslinking these data with civil registration and vital statistics and population-based surveys. Real measurement change requires intentional transfer of leadership to countries with the greatest disease burden and will be achieved by working with centres of excellence and existing networks

    Patterns of antibiotic use, pathogens, and prediction of mortality in hospitalized neonates and young infants with sepsis: A global neonatal sepsis observational cohort study (NeoOBS)

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    BACKGROUND: There is limited data on antibiotic treatment in hospitalized neonates in low- and middle-income countries (LMICs). We aimed to describe patterns of antibiotic use, pathogens, and clinical outcomes, and to develop a severity score predicting mortality in neonatal sepsis to inform future clinical trial design. METHODS AND FINDINGS: Hospitalized infants <60 days with clinical sepsis were enrolled during 2018 to 2020 by 19 sites in 11 countries (mainly Asia and Africa). Prospective daily observational data was collected on clinical signs, supportive care, antibiotic treatment, microbiology, and 28-day mortality. Two prediction models were developed for (1) 28-day mortality from baseline variables (baseline NeoSep Severity Score); and (2) daily risk of death on IV antibiotics from daily updated assessments (NeoSep Recovery Score). Multivariable Cox regression models included a randomly selected 85% of infants, with 15% for validation. A total of 3,204 infants were enrolled, with median birth weight of 2,500 g (IQR 1,400 to 3,000) and postnatal age of 5 days (IQR 1 to 15). 206 different empiric antibiotic combinations were started in 3,141 infants, which were structured into 5 groups based on the World Health Organization (WHO) AWaRe classification. Approximately 25.9% (n = 814) of infants started WHO first line regimens (Group 1-Access) and 13.8% (n = 432) started WHO second-line cephalosporins (cefotaxime/ceftriaxone) (Group 2-"Low" Watch). The largest group (34.0%, n = 1,068) started a regimen providing partial extended-spectrum beta-lactamase (ESBL)/pseudomonal coverage (piperacillin-tazobactam, ceftazidime, or fluoroquinolone-based) (Group 3-"Medium" Watch), 18.0% (n = 566) started a carbapenem (Group 4-"High" Watch), and 1.8% (n = 57) a Reserve antibiotic (Group 5, largely colistin-based), and 728/2,880 (25.3%) of initial regimens in Groups 1 to 4 were escalated, mainly to carbapenems, usually for clinical deterioration (n = 480; 65.9%). A total of 564/3,195 infants (17.7%) were blood culture pathogen positive, of whom 62.9% (n = 355) had a gram-negative organism, predominantly Klebsiella pneumoniae (n = 132) or Acinetobacter spp. (n = 72). Both were commonly resistant to WHO-recommended regimens and to carbapenems in 43 (32.6%) and 50 (71.4%) of cases, respectively. MRSA accounted for 33 (61.1%) of 54 Staphylococcus aureus isolates. Overall, 350/3,204 infants died (11.3%; 95% CI 10.2% to 12.5%), 17.7% if blood cultures were positive for pathogens (95% CI 14.7% to 21.1%, n = 99/564). A baseline NeoSep Severity Score had a C-index of 0.76 (0.69 to 0.82) in the validation sample, with mortality of 1.6% (3/189; 95% CI: 0.5% to 4.6%), 11.0% (27/245; 7.7% to 15.6%), and 27.3% (12/44; 16.3% to 41.8%) in low (score 0 to 4), medium (5 to 8), and high (9 to 16) risk groups, respectively, with similar performance across subgroups. A related NeoSep Recovery Score had an area under the receiver operating curve for predicting death the next day between 0.8 and 0.9 over the first week. There was significant variation in outcomes between sites and external validation would strengthen score applicability. CONCLUSION: Antibiotic regimens used in neonatal sepsis commonly diverge from WHO guidelines, and trials of novel empiric regimens are urgently needed in the context of increasing antimicrobial resistance (AMR). The baseline NeoSep Severity Score identifies high mortality risk criteria for trial entry, while the NeoSep Recovery Score can help guide decisions on regimen change. NeoOBS data informed the NeoSep1 antibiotic trial (ISRCTN48721236), which aims to identify novel first- and second-line empiric antibiotic regimens for neonatal sepsis. TRIAL REGISTRATION: ClinicalTrials.gov, (NCT03721302)
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