3 resultados para Two-stage converter

em Bioline International


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Background: A study of the correlation between the particle size of lignocellulosic substrates and ultrasound pretreatment on the efficiency of further enzymatic hydrolysis and fermentation to ethanol. Results: Themaximumconcentrations of glucose and, to a lesser extent, di- and trisaccharideswere obtained in a series of experiments with 48-h enzymatic hydrolysis of pine rawmaterials ground at 380–400 rpm for 30min. The highest glucose yield was observed at the end of the hydrolysis with a cellulase dosage of 10 mg of protein (204 ± 21 units CMCase per g of sawdust). The greatest enzymatic hydrolysis efficiency was observed in a sample that combined two-stage grinding at 400 rpm with ultrasonic treatment for 5–10 min at a power of 10 W per kg of sawdust. The glucose yield in this case (35.5 g glucose l−1) increased twofold compared to ground substrate without further preparation. Conclusions: Using a mechanical two-stage grinding of lignocellulosic raw materials with ultrasonication increases the efficiency of subsequent enzymatic hydrolysis and fermentation.

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Background: The aim of this study was to assess the quality of rapid HIV testing in South Africa. Method: A two-stage sampling procedure was used to select HCT sites in eight provinces of South Africa. The study employed both semi-structured interviews with HIV testers and observation of testing sessions as a means of data collection. In total, 63 HCT sites (one HIV tester per site) were included in the survey assessing qualification, training, testing practices and attitudes towards rapid tests. Quantitative data was analysed using descriptive statistics and qualitative data was content analysed. Results: Of the 63 HIV testers, 20.6% had a nursing qualification, 14.3% were professional counsellors, 58.7% were lay HIV counsellors and testers and 6.4% were from other professions. Most HIV testers (87.3%) had had a formal training in testing, which ranged between 10-14 days, while 6 (9.5%) had none. Findings revealed sub-standard practices in relation to testing. These were mainly related to non-adherence to testing algorithms, poor external quality control practices, poor handling and communication of discordant results. Conclusion: Quality of HIV rapid testing may be highly compromised through poor adherence to guidelines as observed in our study.

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The increased prevalence of iron deficiency among infants can be attributed to the consumption of an iron deficient diet or a diet that interferes with iron absorption at the critical time of infancy, among other factors. The gradual shift from breast milk to other foods and liquids is a transition period which greatly contributes to iron deficiency anaemia (IDA). The purpose of this research was to assess iron deficiency anaemia among infants aged six to nine months in Keiyo South Sub County. The specific objectives of this study were: to establish the prevalence of infants with iron deficiency anaemia and dietary iron intake among infants aged 6 to 9 months. The cross sectional study design was adopted in this survey. This study was conducted in three health facilities in Keiyo South Sub County. The infants were selected by use of a two stage cluster sampling procedure. Systematic random sampling was then used to select a total of 244 mothers and their infants. Eighty two (82) infants were selected from Kamwosor sub-district hospital and eighty one (81) from both Nyaru and Chepkorio health facilities. Interview schedules, 24-hour dietary recall and food frequency questionnaires were used for collection of dietary iron intake. Biochemical tests were carried out by use of the Hemo-control photochrometer at the health facilities. Infants whose hemoglobin levels were less than 11g/dl were considered anaemic. Further, peripheral blood smears were conducted to ascertain the type of nutritional anaemia. Data was analyzed using the Statistical Package for Social Sciences (SPSS) computer software version 17, 2009. Dietary iron intake was analyzed using the NutriSurvey 2007 computer software. Results indicated that the mean hemoglobin values were 11.3± 0.84 g/dl. Twenty one percent (21.7%) of the infants had anaemia and further 100% of peripheral blood smears indicated iron deficiency anaemia. Dietary iron intake was a predictor of iron deficiency anaemia in this study (t=-3.138; p=0.01). Iron deficiency anaemia was evident among infants in Keiyo South Sub County. The Ministry of Health should formulate and implement policies on screening for anaemia and ensure intensive nutrition education on iron rich diets during child welfare clinics.