200 research outputs found
Composition-structure-property effects of antimony in soda-lime-silica glasses
Float glass-type SiO2-Na2O-CaO glasses with 0 – 10 mol% Sb2O3 were melted and
their compositional, structural, thermal and optical properties characterised. All glasses
were X-ray amorphous and increasing Sb2O3 content progressively decreased glass
transition temperature (Tg) and dilatometric softening point (Td), despite increases in
Al2O3 content from greater crucible corrosion.
121Sb Mössbauer spectroscopy confirmed
that Sb was predominantly incorporated as Sb3+ (Sb3+/ΣSb ~ 0.9) and Raman
spectroscopy showed that Sb substantially decreased average (Si, Al)-O Q
n
speciation.
Both techniques confirmed that Sb3+ ions were incorporated in trigonal pyramidal [:SbO3]
polyhedra. XRF and Raman spectroscopies confirmed that SO3 content decreased with
increasing Sb2O3 content. TGA analysis showed, as a linear function of Sb2O3 content,
mass gain commencing at 700°C, reaching a maximum at 1175°C, then mass loss
above 1175°C, consistent with oxidation (Sb3+ → Sb5+) then reduction (Sb5+ → Sb3+).
The TGA samples were shown to have attained or approached Sb redox equilibrium
during measurement. Optical absorption spectroscopy (UV-Vis-nIR) showed red-shifts
of the UV absorption edge with increasing Sb2O3 content, consistent with increasing
intensity of far-UV absorption bands from Sb3+ and Sb5+ s→p transitions. UV-Vis-nIR
fluorescence spectroscopy evidenced a broad luminescence band centred at ~25,000
cm-1
, attributed to the 3P1→1S0 transition of Sb3+
, which is Stokes shifted by ~15,000
cm-1
from the 1S0→3P1 absorption at ~40,000 cm-1
. The most intense emission occurred
at 0.5 mol% Sb2O3, with concentration quenching reducing luminescence intensities at
higher Sb2O3 contents. Additions of Sb2O3 to float-type soda-lime-silica glasses could
thus enable lower melting energies and/or new solar energy applications
Prevalence of dyslipidaemia and associated risk factors in a rural population in south-western Uganda : a community based survey
BACKGROUND: The burden of dyslipidaemia is rising in many low income countries. However, there are few data on the prevalence of, or risk factors for, dyslipidaemia in Africa. METHODS: In 2011, we used the WHO Stepwise approach to collect cardiovascular risk data within a general population cohort in rural south-western Uganda. Dyslipidaemia was defined by high total cholesterol (TC) ≥ 5.2 mmol/L or low high density lipoprotein cholesterol (HDL-C) 6% (men aOR=3.00, 95%CI=1.37-6.59; women aOR=2.74, 95%CI=1.77-4.27). The odds of high TC was also higher among married men, and women with higher education or high BMI. CONCLUSION: Low HDL-C prevalence in this relatively young rural population is high whereas high TC prevalence is low. The consequences of dyslipidaemia in African populations remain unclear and prospective follow-up is required
Traditional knowledge on zootherapeutic uses by the Saharia tribe of Rajasthan, India
The present zootherapeutic study describes the traditional knowledge related to the use of different animals and animal-derived products as medicines by the Saharia tribe reside in the Shahabad and Kishanganj Panchayat Samiti's of Baran district of Rajasthan, India. A field survey was conducted from April to June 2006 by performing interview through structured questionnaire with 21 selected respondents, who provided information regarding use of animals and their products in folk medicine. A total of 15 animal species were recorded and they are used for different ethnomedical purposes, including cough, asthma, tuberculosis, paralysis, earache, herpes, weakness, muscular pain etc. The zootherapeutic knowledge was mostly based on domestic animals, but some protected species like the peacock (Pavo cristatus,), hard shelled turtle (Kachuga tentoria), sambhar (Cervus unicolor) were also mentioned as medicinal resources. We would suggest that this kind of neglected traditional knowledge should be included into the strategies of conservation and management of faunistic resources. Further studies are required for experimental validation to confirm the presence of bioactive compounds in these traditional remedies and also to emphasize more sustainable use of these resources
Genital Herpes Has Played a More Important Role than Any Other Sexually Transmitted Infection in Driving HIV Prevalence in Africa
Extensive evidence from observational studies suggests a role for genital herpes in the HIV epidemic. A number of herpes vaccines are under development and several trials of the efficacy of HSV-2 treatment with acyclovir in reducing HIV acquisition, transmission, and disease progression have just reported their results or will report their results in the next year. The potential impact of these interventions requires a quantitative assessment of the magnitude of the synergy between HIV and HSV-2 at the population level.A deterministic compartmental model of HIV and HSV-2 dynamics and interactions was constructed. The nature of the epidemiologic synergy was explored qualitatively and quantitatively and compared to other sexually transmitted infections (STIs). The results suggest a more substantial role for HSV-2 in fueling HIV spread in sub-Saharan Africa than other STIs. We estimate that in settings of high HSV-2 prevalence, such as Kisumu, Kenya, more than a quarter of incident HIV infections may have been attributed directly to HSV-2. HSV-2 has also contributed considerably to the onward transmission of HIV by increasing the pool of HIV positive persons in the population and may explain one-third of the differential HIV prevalence among the cities of the Four City study. Conversely, we estimate that HIV had only a small net impact on HSV-2 prevalence.HSV-2 role as a biological cofactor in HIV acquisition and transmission may have contributed substantially to HIV particularly by facilitating HIV spread among the low-risk population with stable long-term sexual partnerships. This finding suggests that prevention of HSV-2 infection through a prophylactic vaccine may be an effective intervention both in nascent epidemics with high HIV incidence in the high risk groups, and in established epidemics where a large portion of HIV transmission occurs in stable partnerships
Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.
BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700
A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)
Meeting abstrac
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