Scientific support for an orbiter middeck experiment on solid surface combustion

The objective is to determine the mechanism of gas-phase flame spread over solid fuel surfaces in the absence of any buoyancy or externally imposed gas-phase flow. Such understanding can be used to improve the fire safety aspects of space travel by providing information that will allow judicious selections of spacecraft materials and environments to be made. The planned experiment consists of measuring the flame spread rate over thermally thin and thermally thick fuels in a closed container in the low-gravity environment of the Space Shuttle. Measurements consist of flame spread rate and shape obtained from two views of the process as recorded on movie film and surface and gas-phase temperatures obtained from fine-wire thermocouples. The temperature measurements along with appropriate modeling provide information about the gas-to-solid heat flux. Environmental parameters to be varied are the oxygen concentration and pressure

Theory of the propagation dynamics of spiral edges of diffusion flames in von Kármán swirling flows

This analysis addresses the propagation of spiral edge flames found in von Kármán swirling flows induced in rotating porous-disk burners. In this configuration, a porous disk is spun at a constant angular velocity in an otherwise quiescent oxidizing atmosphere. Gaseous methane is injected through the disk pores and burns in a flat diffusion flame adjacent to the disk. Among other flame patterns experimentally found, a stable, rotating spiral flame is observed for sufficiently large rotation velocities and small fuel flow rates as a result of partial extinction of the underlying diffusion flame. The tip of the spiral can undergo a steady rotation for sufficiently large rotational velocities or small fuel flow rates, whereas a meandering tip in an epicycloidal trajectory is observed for smaller rotational velocities and larger fuel flow rates. A formulation of this problem is presented in the equidiffusional and thermodiffusive limits within the framework of one-step chemistry with large activation energies. Edge-flame propagation regimes are obtained by scaling analyses of the conservation equations and exemplified by numerical simulations of straight two-dimensional edge flames near a cold porous wall, for which lateral heat losses to the disk and large strains induce extinction of the trailing diffusion flame but are relatively unimportant in the front region, consistent with the existence of the cooling tail found in the experiments. The propagation dynamics of a steadily rotating spiral edge is studied in the large-core limit, for which the characteristic Markstein length is much smaller than the distance from the center at which the spiral tip is anchored. An asymptotic description of the edge tangential structure is obtained, spiral edge shapes are calculated, and an expression is found that relates the spiral rotational velocity to the rest of the parameters. A quasiestatic stability analysis of the edge shows that the edge curvature at extinction in the tip region is responsible for the stable tip anchoring at the core radius. Finally, experimental results are analyzed, and theoretical predictions are tested

Abdominal tuberculosis: Diagnosis and demographics, a 10-year retrospective review from a single centre.

AIM: To review all cases of abdominal tuberculosis (ATB) for demographic details, diagnostic work up and evidence of vitamin D deficiency. METHODS: This was a retrospective analysis of all patients diagnosed with ATB from June 2003 to August 2013 at St George's Hospital, London. Demographic data was available from the local tuberculosis database. Further clinical information was collected from electronic patient records, including radiology, endoscopy, microbiology, histology, biochemistry and serology. Patients were classified as either confirmed ATB [if mycobacteria tuberculosis (MTB) was cultured from abdominal site] or presumed ATB (if suggestive findings or high clinical suspicion). Subtypes of ATB were classified as tuberculosis (TB) peritonitis, luminal TB, solid organ TB or from a combination of sites. RESULTS: There were a total of 65 cases identified in this time period, with a mean of 6.5 cases per year (range 4-9). Mean age 42 years, 49.2% females. Fifty-two point three percent were South Asian, 38.5% African. Forty-nine point two percent had gastrointestinal endoscopy, 30.8% paracentesis and 24.6% surgery in order to obtain samples. Forty-seven point seven percent were defined as confirmed ATB with positive culture of MTB from abdominal sites, the rest were treated as presumed ATB. Twenty-four point six percent had co-existing sputum culture positive for MTB, and 30.8% had an abnormal chest X-ray. Subtypes of ATB: 35.4% had TB peritonitis; 27.7% luminal TB; 3.1% solid organ TB; and 33.8% TB at a combination of abdominal sites. Thirteen point nine percent were human immunodeficiency virus positive, all with CD4 count less than 300 cells/μL. Seventy point five percent had severe vitamin D deficiency, and 25% were vitamin D deficient. CONCLUSION: ATB mainly affects young South Asian and African patients, with difficulties in confirming diagnosis despite a range of non-invasive and invasive diagnostic tests

Lesions mimicking lacrimal gland pleomorphic adenoma

Aim: To report a series of patients with lacrimal gland lesions simulating the clinicoradiological features of lacrimal gland pleomorphic adenoma (LGPA). Methods: Multicentre retrospective, interventional case series. Clinical records of all patients with lesions mimicking LGPA seen in five orbital units were reviewed. Results: The study included 14 patients (seven men and seven women) with a mean age of 50.9 years. The diagnosis of LGPA was made in all cases by experienced orbital surgeons, based on clinicoradiological features, and lacrimal gland excision was performed. Postoperative histology revealed lymphoma (four patients), chronic dacryoadenitis (three patients), adenoid cystic carcinoma (two patients), Sjogren's syndrome (two patients), cavernous haemangioma (one patient), benign lymphoid hyperplasia (one patient) and granulomatous dacryoadenitis (one patient). Comparison with the total number of histologically confirmed LGPA cases seen during the study period revealed that 22.6% of cases of suspected LGPA were misdiagnosed based on clinicoradiological criteria. Conclusions: Many different lesions may mimic the clinicoradiological features of LGPA. The accepted clinicoradiological criteria used for the diagnosis of LGPA have a high false-positive rate, even in experienced hands. Based on this study, the authors believe that fine-needle aspiration biopsy or intraoperative biopsy and frozen section diagnosis may help reduce unnecessary lacrimal gland excision.Venkatesh C Prabhakaran, Paul S Cannon, Alan McNab, Garry Davis, Brett O’Donnell, Peter J Dolman, Raf Ghabrial, Dinesh Selv

Microgravity Droplet Combustion in CO2 Enriched Environments at Elevated Pressures

Microgravity droplet combustion experiments were performed in elevated concentrations of CO2 at pressures of 1.0 atm, 3.0 atm, and 5.0 atm to examine the effects of a radiatively participating suppression agent in space applications. Methanol and n-heptane droplets, with an initial diameter of 2.0 mm supported on a quartz fiber, were used in these experiments. The ambient O2 concentration was held constant at 21% and the CO2 concentrations ranged from 0% to a maximum of 70%, by volume with the balance consisting of N2 . Results from the methanol tests showed slight decreases in burning rates with increased CO2 concentrations at all ambient pressures. The n-heptane tests show slight increases in burning rates with increasing CO2 concentrations at each pressure level. Instantaneous radiative heat flux was also measured using both a broadband radiometer (i.e., wavelengths from 0.6 microns to 40.0 microns) and a narrowband radiometer (i.e., centered at 5.6 microns with a filter width at half maximum of 1.5 microns). Radiative exchanges between the droplet and surrounding gases as well as the soot field produce departures from the classical quasisteady theory which would predict a decrease in burning rates with increasing CO2 concentrations in microgravity

Polypharmacy Treatment of Hypertensionin Public Health Centers

Background: Hypertension is one of the most prominent global diseases. Despite the availability of effective therapies, hypertension remains poorly controlled in Indonesia. In many cases, patient’s noncompliance may be attributable to the low patients’ knowledge, attitude, and life-style practices such as polypharmacy. Polypharmacy is defined as the administration of many drugs at in one prescription. Polypharmacy increases expenses, possible adverse reaction to a single agent, incidence of drug interactions, and decreases patient’s compliance This study aimed to identify the practice of polypharmacy in hypertension treatment in primary health centers.Methods: A cross-sectional descriptive observational study was carried out on 60 patients from two primary health centers in Jatinangor, West Java, Indonesia in October 2013. Sociodemographic profile, degree of hypertension, types of antihypertensive drugs, concomitant drugs given together with antihypertensive drugs, and treatment compliance data were collected and presented in tables and figures.Results: The incidence of hypertension was more common among male patients compared to female patients. Thirty-three patients (55%) have low compliance to their medication. Twenty-nine patients (48%) received single drug and 31 patients (52%) received more than one drugs.Conclusions: The percentage of polypharmacy practice in treating hypertension in primary health centers is 52%. The most frequently prescribed anti-hypertensive are angiotensin-converting enzyme (ACE) inhibitors and calcium-channel blockers (CCB). Most of hypertensive patients have low compliance to therapy. [AMJ.2016;3(4):633–9] DOI: 10.15850/amj.v3n4.95

Scaling up prevention and treatment towards the elimination of hepatitis C: a global mathematical model

Background The revolution in hepatitis C virus (HCV) treatment through the development of direct-acting antivirals (DAAs) has generated international interest in the global elimination of the disease as a public health threat. In 2017, this led WHO to establish elimination targets for 2030. We evaluated the impact of public health interventions on the global HCV epidemic and investigated whether WHO's elimination targets could be met. Methods We developed a dynamic transmission model of the global HCV epidemic, calibrated to 190 countries, which incorporates data on demography, people who inject drugs (PWID), current coverage of treatment and prevention programmes, natural history of the disease, HCV prevalence, and HCV-attributable mortality. We estimated the worldwide impact of scaling up interventions that reduce risk of transmission, improve access to treatment, and increase screening for HCV infection by considering six scenarios: no change made to existing levels of diagnosis or treatment; sequentially adding the following interventions: blood safety and infection control, PWID harm reduction, offering of DAAs at diagnosis, and outreach screening to increase the number diagnosed; and a scenario in which DAAs are not introduced (ie, treatment is only with pegylated interferon and oral ribavirin) to investigate the effect of DAA use. We explored the effect of varying the coverage or impact of these interventions in sensitivity analyses and also assessed the impact on the global epidemic of removing certain key countries from the package of interventions. Findings By 2030, interventions that reduce risk of transmission in the non-PWID population by 80% and increase coverage of harm reduction services to 40% of PWID could avert 14·1 million (95% credible interval 13·0–15·2) new infections. Offering DAAs at time of diagnosis in all countries could prevent 640 000 deaths (620 000–670 000) from cirrhosis and liver cancer. A comprehensive package of prevention, screening, and treatment interventions could avert 15·1 million (13·8–16·1) new infections and 1·5 million (1·4–1·6) cirrhosis and liver cancer deaths, corresponding to an 81% (78–82) reduction in incidence and a 61% (60–62) reduction in mortality compared with 2015 baseline. This reaches the WHO HCV incidence reduction target of 80% but is just short of the mortality reduction target of 65%, which could be reached by 2032. Reducing global burden depends upon success of prevention interventions, implemention of outreach screening, and progress made in key high-burden countries including China, India, and Pakistan. Interpretation Further improvements in blood safety and infection control, expansion or creation of PWID harm reduction services, and extensive screening for HCV with concomitant treatment for all are necessary to reduce the burden of HCV. These findings should inform the ongoing global action to eliminate the HCV epidemic

Risk of early horizontal transmission of hepatitis B virus in children of uninfected mothers in sub-Saharan Africa: a systematic review and meta-analysis

Background Sub-Saharan Africa is highly endemic for hepatitis B virus (HBV); historically, most people were exposed during childhood through vertical or horizontal transmission. Although all African countries now provide a three-dose infant hepatitis B vaccination starting at age 6–8 weeks, only a third of African countries have introduced birth dose (HepB-BD) vaccine. Adding HepB-BD is fundamental to prevent vertical transmission, but its effectiveness in preventing horizontal transmission, compared with the three-dose infant vaccination alone, is unknown. We aimed to estimate the risk of early horizontal transmission in children of hepatitis B surface antigen (HBsAg)-negative mothers in sub-Saharan Africa stratified according to the vaccination schedule. Methods In this systematic review and meta-analysis we searched MEDLINE, Global Health, Embase, African Index Medicus and African Journals Online from their inception to Oct 24, 2022, for studies reporting HBsAg or HBV DNA, or both, in children (aged 0–5 years) of HBsAg-negative mothers. We excluded studies if children were only tested at birth. Two reviewers independently screened the titles and abstracts of all articles and data were extracted using a standardised pre-piloted data extraction sheet, and authors were contacted if any important information was missing. The primary outcome was the risk of HBV infection in children of HBsAg-negative mothers, stratified by vaccination schedule (no vaccination, first dose at 6–8 weeks, or first dose at birth). We pooled the child risks of HBsAg or HBV DNA-positivity from the age of 0 years to 5 years via a random-effect meta-analysis using a generalised linear mixed model. The study was registered on PROSPERO, CRD42021236203. Findings Of 8856 articles identified, 27 studies evaluating 10 003 children of HBsAg-negative mothers were included. The pooled risks of infection were 6·16% (95% CI 3·05–12·04; 155/1407) in the no vaccination group, 0·21% (0·04–1·15; 10/3425) in children who received their first dose at 6–8 weeks, and 0·05% (0·00–1·32; 3/2902) in children who received their first dose at birth. The difference was not statistically significant in children who received their first dose at 6–8 weeks and children who received their first dose at birth after adjusting for the study period, region, and maternal HIV status (test of moderators p=0·37). Interpretation In children of HBsAg-negative mothers, the risk of infection might be minimal even with the vaccination starting at 6–8 weeks, without clear additional benefit from HepB-BD. When births take place at home and timely administration of HepB-BD is challenging, antenatal HBsAg screening and selective HepB-BD might allow efficient allocation of resources to mother and child pairs at high risk compared with universal HepB-BD

A comparative study to assess the lifestyle practices among government and private school teachers with hypertension in selected schools, Erode district

A comparative study to assess the lifestyle practices among Government and Private school teachers with hypertension at selected schools, Erode district was done by Anish V Nayagam as a partial fulfillment of the requirement of the Degree of Master of Science in Nursing at Shivparvathi Mandradiar Institute of Health Science, under the Tamil Nadu Dr. M. G. R. Medical University, Chennai, April 2016. The Objectives of the study were : 1. To assess the lifestyle practices of Government and private school teachers with Hypertension. 2. To compare the lifestyle practices of Government and private school teachers with Hypertension. 3. To find out the association between the lifestyle practices and the selected background factors among Government and private school teachers with Hypertension. The Research Hypothesis formulated and tested were : H1 : There is a significant difference in the lifestyle practices among Government and private school teachers with Hypertension. H2 : There is a significant association between the lifestyle practices and their selected background factors among Government and private school teachers with Hypertension. Review of literature was done in the following heading, 1. Studies related to the prevalence and determinants of hypertension, 2. Studies related to knowledge and attitude regarding hypertension The conceptual framework for the present study is formulated by the investigator based on Roy’s adaptation model. The research design used was a non experimental descriptive comparative design. The data collection tool was validated by a physician and the four nursing experts. Reliability was established by test - retest method, r = 0.9 for the structured knowledge questionnaire. The samples (82) for the study were chosen by using purposive sampling technique, Data was collected by using Structured Questionnaire regarding Lifestyle Practice. Data was collected for a period of One month. The data collected were edited, tabulated, analyzed and interpreted manually. The obtained mean value was 4, SD 6.69, Range, 23 among Government school teachers with hypertension whereas among private school teachers with hypertension the obtained mean value was 56, SD 5.6, Range 24 and Mean difference of lifestyle practices between Government and Private school teachers was 9, and the obtained ‘t’ value was 5.4 which was significance at the level of P<0.05. The findings of the study revealed that there was a significant difference in the lifestyle practices between the Government and Private school teachers with hypertension. There was a significant association between the lifestyle practices and the selected demographic variable monthly income of the participant among private school teachers with hypertension. None of the demographic varaibles were associated with lifestyle practices among government school teachers with hypertension. The implications, limitations, recommendations and conclusion were clearly spelt

Methanol Droplet Combustion in Oxygen-Inert Environments in Microgravity

The Flame Extinguishment (FLEX) experiment that is currently underway in the Combustion Integrated Rack facility onboard the International Space Station is aimed at understanding the effects of inert diluents on the flammability of condensed phase fuels. To this end, droplets of various fuels, including alkanes and alcohols, are burned in a quiescent microgravity environment with varying amounts of oxygen and inert diluents to determine the limiting oxygen index (LOI) for these fuels. In this study we report experimental observations of methanol droplets burning in oxygen-nitrogen-carbon dioxide and oxygen-nitrogen-helium gas mixtures at 0.7 and 1 atmospheric pressures. The initial droplet size varied between approximately 1.5 mm and 4 mm to capture both diffusive extinction brought about by insufficient residence time at the flame and radiative extinction caused by excessive heat loss from the flame zone. The ambient oxygen concentration varied from a high value of 30% by volume to as low as 12%, approaching the limiting oxygen index for the fuel. The inert dilution by carbon dioxide and helium varied over a range of 0% to 70% by volume. In these experiments, both freely floated and tethered droplets were ignited using symmetrically opposed hot-wire igniters and the burning histories were recorded onboard using digital cameras, downlinked later to the ground for analysis. The digital images yielded droplet and flame diameters as functions of time and subsequently droplet burning rate, flame standoff ratio, and initial and extinction droplet diameters. Simplified theoretical models correlate the measured burning rate constant and the flame standoff ratio reasonably well. An activation energy asymptotic theory accounting for time-dependent water dissolution or evaporation from the droplet is shown to predict the measured diffusive extinction conditions well. The experiments also show that the limiting oxygen index for methanol in these diluent gases is around 12% to 13% oxygen by volume