995 research outputs found
Clinical utility of folate-containing oral contraceptives
Folate is a generic term for a water-soluble B-complex vitamin which plays an important role in protein synthesis and metabolism and other processes related to cell multiplication and tissue growth. Pregnant and lactating women are at increased risk of folic acid deficiency because generally their dietary folate is insufficient to meet their physiological requirements and the metabolic demands of the growing fetus. The evidence pertaining to the reduction of the risk of neural tube defects (NTDs) due to folate is so compelling that supplementation with 400 μg of folic acid to all women trying to conceive until 12 weeks of pregnancy has been recommended by every relevant authority. A recent Cochrane review has also found protective effects of folate supplementation in occurrence and reoccurrence of NTDs. Despite food fortification and targeted public health campaigns promoting folic acid supplementation, 4,300,000 new cases occur each year worldwide resulting in an estimated 41,000 deaths and 2.3 million disability-adjusted life years (DALYS). This article will review the burden and risk factors of NTDS, and the role of folate in preventing NTDs. It will also describe different modes of supplementing folate and the newer evidence of the effectiveness of adding folate in oral contraceptives for raising serum and red blood cell folate levels
Slurry Erosive Wear Behavior of Hot Extruded Al6061-Si3N4 Composite
Silicon nitride possess excellent hot hardness and wear resistance coupled with very good corrosion resistance. Hence, in recent years, silicon nitride has been a serious contender as a reinforcement to develop light weight metal matrix composites for several technological applications. Al6061 is most popular matrix alloy as it possess excellent formability and in particular the quality of extrudates of Al6061 is quite high and are the most preferred in space and naval applications especially for support structures and torpedoes blades respectively. Improved corrosion and slurry erosion resistance on use of silicon nitride in nickel and aluminum alloy matrices have been reported by several researchers. In the light of the above, this paper focuses on development of Al6061- 6wt% Si3N4 by stir casting the most economical and popular route followed by hot extrusion. Hot extrusion was carried out using 200T hydraulic press at extrusion ratio of 1:10 at a temperature of 5500C. Slurry erosion tests were carried out using 3.5% NaCl solution containing silica sand particles of size 312 μm at different rotational speeds varying between 300 rpm and 1200 rpm. The sand concentration was varied from 10 g/l to 40 g/l. Under identical test conditions, hot extruded Al6061- 6wt% Si3N4 composite do possess better slurry erosion resistance when compared with matrix alloy. The mechanism involved in the material removal process during slurry erosion process will also be discussed
Material Characterization and Real-Time Wear Evaluation of Pistons and Cylinder Liners of the Tiger 131 Military Tank
Material characterisation and wear evaluation of the original and replacement pistons and cylinder-liners of Tiger 131 is reported. Original piston and cylinder-liner were operative in the Tigers’ engine during WWII. The replacement piston and cylinder-liner were used as substitutes and were obtained after failure in two hours of operation in the actual engine. Material characterisation revealed that the original piston was aluminium silicon hypereutectic alloy whereas the replacement piston was aluminium copper alloy with very low silicon content. Both original and replacement cylinder-liners consisted of mostly iron which is indicative of cast iron, a common material for this application. The replacement piston average surface roughness was found to be 9.09 μm while for replacement cylinder-liner it was 5.78 μm
Health care seeking for maternal and newborn illnesses in low- and middle-income countries: A systematic review of observational and qualitative studies
Background: In low- and middle-income countries, a large number of maternal and newborn deaths occur due to delays in health care seeking. These delays occur at three levels i.e. delay in making decision to seek care, delay in access to care, and delay in receiving care. Factors that cause delays are therefore need to be understand to prevent and avoid these delays to improve health and survival of mothers and babies. Methods: A systematic review of observational and qualitative studies to identify factors and barriers associated with delays in health care seeking. Results: A total of 159 observational and qualitative studies met the inclusion criteria. The review of observational and qualitative studies identified social, cultural and health services factors that contribute to delays in health care seeking, and influence decisions to seek care. Timely recognition of danger signs, availability of finances to arrange for transport and affordability of health care cost, and accessibility to a health facility were some of these factors. Conclusions: Effective dealing of factors that contribute to delays in health care seeking would lead to significant improvements in mortality, morbidity and care seeking outcomes, particularly in countries that share a major brunt of maternal and newborn morbidity and mortality. Registration: PROSPERO CRD42012003236
Promoting female participation in professional development programmes
A recent publication of the Ministry of Education, Islamabad, shows that the province of Sindh has a population of over 30 million. The overall literacy rate in this province is 46.7 %, while the female literacy rate is 35.4%. However, in the rural areas of Sindh the female literacy rate is 13.11% against the male literacy rate of 52.1%. There are many social, cultural and economic factors that inhibit females from availing opportunities on an equal basis with the other segments of society. The literature also reveals that due to the above-mentioned factors females are confined to play a passive role in general and in the education sector in particular. According to a recent UNDP publication, there is considerable disparity between males and females in terms of professional development. Considering the importance of professional development of females in the education sector in Sindh, the Aga Khan University Institute for Educational Development (AKU-IED), under the Pakistan Non- Government Initiatives (PNI-II), took an initiative to launch a project titled ‘Strengthening the Capacity of NGOs/CBOs’. The project targeted to provide opportunities of professional development to 258 individuals, but the actual number of those who graduated was 388, considerably exceeding the planned target. Out of 388, 68 % (262) were females, which show the enthusiasm and commitment of the participants, collaborating NGOs/CBOs and AKU-IED towards the professional development of females. Through this initiative, females were trained as ‘agents of change’ to motivate their communities towards education of their children, in particular the girl child. This presentation unfolds the learning experiences of the USAID Project-III team in promoting female participation in professional development programmes at AKU-IED
Air jet Erosion Wear behavior of Al6061-SiC-Carbon fibre Hybrid Composite
Currently, the focus in materials development is on processing of hybrid metal matrix composites (MMC’s) in particular aluminum (Al) based owing to their flexibility in achieving tailor made properties. Till date, only processing, characterization of mechanical and adhesive wear behavior of various hybrid MMCs have received much attention. However, solid erosion wear of hybrid MMCs has not yet been reported. This assessment will further enlarge the range of applications of hybrid MMCs in particular for components in operation for military applications especially in desert areas. In the light of the above, the present paper discusses the air jet erosion behavior of developed Al6061-SiC-carbon fibre hybrid composite prepared by combination of powder metallurgy and casting process followed by hot extrusion at temperature of 550oC using extrusion ratio of 1:4. The solid sand erodent particle size used was 312 μm while the operating pressure and velocity was maintained at 1.4 bar and 30 m/sec respectively. The adopted feed rate of the sand particles was 2.0 g/min with standoff distance being 10 mm. The sample size was 25 mm x 25 mm x 10 mm. The effect of silicon carbide (SiC), Carbon fibre (Cf), test duration and angle of impingement of the erodent on the erosion wear loss of the developed hybrid composite will be discussed at length
Overestimation of Vitamin a Supplementation Coverage from District Tally Sheets Demonstrates Importance of Population-Based Surveys for Program Improvement: Lessons from Tanzania.
Tanzania has conducted a national twice-yearly Vitamin A supplementation (VAS) campaign since 2001. Administrative coverage rates based on tally sheets consistently report >90% coverage; however the accuracy of these rates are uncertain due to potential errors in tally sheets and their aggregation, incomplete or inaccurate reporting from distribution sites, and underestimating the target population. The post event coverage survey in Mainland Tanzania sought to validate tally-sheet based national coverage estimates of VAS and deworming for the June 2010 mass distribution round, and to characterize children missed by the national campaign. WHO/EPI randomized cross-sectional cluster sampling methodology was adapted for this study, using 30 clusters by 40 individuals (n = 1200), in addition to key informant interviews. Households with children 6-59 months of age were included in the study (12-59 months for deworming analysis). Chi-squared tests and logistic regression analysis were used to test differences between children reached and not reached by VAS. Data was collected within six weeks of the June 2010 round. A total of 1203 children, 58 health workers, 30 village leaders and 45 community health workers were sampled. Preschool VAS coverage was 65% (95% CI: 62.7-68.1), approximately 30% lower than tally-sheet coverage estimates. Factors associated with not receiving VAS were urban residence [OR = 3.31; p = 0.01], caretakers who did not hear about the campaign [OR = 48.7; p<0.001], and Muslim households [OR<3.25; p<0.01]. There were no significant differences in VAS coverage by child sex or age, or maternal age or education. Coverage estimation for vitamin A supplementation programs is one of most powerful indicators of program success. National VAS coverage based on a tally-sheet system overestimated VAS coverage by ∼30%. There is a need for representative population-based coverage surveys to complement and validate tally-sheet estimates
Zinc supplementation as an adjunct to antibiotics in the treatment of pneumonia in children 2 to 59 months of age
Background:Diarrhoeal disorders and acute respiratory infections (ARIs), especially pneumonia, are the most common causes of death in low-income countries. Studies evaluating the impact of zinc supplementation as an adjunct in the management of pneumonia are limited and have shown variable results.Objectives: To evaluate zinc supplementation, as an adjunct to antibiotics, in the treatment (clinical recovery) of pneumonia in children aged two to 59 months.Search strategy: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 1), which contains the Cochrane Acute Respiratory Infections (ARI) Group\u27s and the Cochrane Infectious Diseases Group\u27s Specialised Registers, MEDLINE (1950 to March week 2, 2011), EMBASE (1974 to March 2011), CINAHL (1981 to March 2011), LILACS (1985 to March 2011), AMED (1985 to March 2011), CAB Abstracts (1910 to March 2011) and Web of Science (2000 to March 2011).Selection criteria: Randomised control trials (RCTs) evaluating supplementation of zinc as an adjunct to antibiotics for pneumonia in children aged two to 59 months.Data collection and analysis: Two review authors independently assessed trial eligibility and screened all available titles and abstracts for inclusion. If the relevance could not be ascertained by screening the title and abstract, we retrieved and reviewed the full text of the article.Main results: We included four trials in which 3267 children aged two to 35 months participated. Analysis showed that zinc supplementation in addition to standard antibiotic therapy in children with severe and non-severe pneumonia failed to show a statistically significant effect on clinical recovery (risk ratio (RR) 1.02, 95% confidence interval (CI) 0.93 to 1.11). Similary, zinc supplementation in children with severe pneumonia, as an adjunct to standard antibiotic therapy, did not show a statistically significant effect on clinical recovery measured as resolution of tachypnoea (respiratory rate \u3e 50 breaths per minute) (RR 1.13, 95% CI 0.82 to 1.57) and cessation of chest indrawing (RR 1.08, 95% CI 0.88 to 1.31) as compared to the control group. Zinc supplementation in children with severe pneumonia also showed a non-significant effect on the duration of hospitalization stay as compared to the control (RR 1.04, 95% CI 0.89 to 1.22).Authors\u27 Conclusion: Evidence provided in this review is insufficient to recommend the use of zinc as an adjunct to standard antibiotic therapy for pneumonia in children aged two to 35 months
Effect of community based interventions on childhood diarrhea and pneumonia: uptake of treatment modalities and impact on mortality
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