66 research outputs found

    Repeated-batch ethanol fermentation from sweet sorghum juice by free cells of Saccharomyces cerevisiae NP 01

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    Low-cost inoculum preparation (IP) media for ethanol production were developed. It was found that sweet sorghum juice (SSJ) containing 100 g l-1 of total sugar without nutrient supplement could be used as the low-cost IP medium instead of the typical IP medium or yeast extract malt extract (YM) medium. Ethanol production from the SSJ (total soluble solids of 24 °Bx) by the inoculum of Saccharomyces cerevisiae NP 01 in batch and repeated-batch fermentations was then investigated. The fermentations were carried out under static condition in 500 ml air-locked Erlenmeyer flasks at 30°C and the initial yeast cell concentration was 1×108 cells ml-1. In the batch fermentation, the concentration (P), productivity (Qp) and yield (Yp/s) of ethanol were 110.09 ± 0.81 g l-1, 2.29 ± 0.01 g l-1 h-1 and 0.51 ± 0.02, respectively. In the repeated-batch fermentation, the yeasts could be used at least eight successive batches without a marked decrease in ethanol production. The repeated-batch fermentation with fill and drain volume at 75% of the working volume gave higher ethanol production efficiencies than those at 50% of the working volume in terms of total ethanol production rate (g h-1). The average P, Qp and Yp/s of the eight successive batches at 75% fill and drain volume in a 2 L bioreactor at the agitation rate of 100 rev min-1 were 93.30 ± 9.44 g l-1, 1.21 ± 0.43 g l-1 h-1 and 0.48 ± 0.03, respectively.Key words: Repeated-batch, ethanol fermentation, low-cost nutrient, sweet sorghum juice, Saccharomyces cerevisiae

    Improvement of gas chromatographic analysis for organic acids and solvents in acetone-butanolethanol fermentation from sweet sorghum juice

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    Modern development for gas chromatographic peak recognition of organic acids and organic solvents in acetone-butanol-ethanol (ABE) fermentation was investigated under different temperature programmes. Either propanol or iso-butanol was used as an internal standard. The results showed that short retention time and fair recognition peak of the compounds were obtained under the following column temperature programme: 10 min at 150°C, 15°C/min to 180°C and 20 min at 180°C. The appearance of the chromatograms showed that iso-butanol allowed higher resolution and satisfactory peak shape for the tested compounds than propanol. Calibration curve between ratios of standard peak area per internal standard peak area and concentrations of the organic acids and organic solvents under these conditions had a good linear correlation with R2 ≥ 0.998. When ABE fermentation by Clostridium beijerinckii JCM1390 from sweet sorghum juice was carried out in a 2-L fermenter, the highest butanol concentration was 7.56 g/l with the butanol yield of 0.33 g/g sugar utilized.Key words: Acetone-butanol-ethanol fermentation, column temperature programme, gas chromatography, sweet sorghum juice

    Time to Update and Quantitative Changes in the Results of Cochrane Pregnancy and Childbirth Reviews

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    BACKGROUND: The recommended interval between updates for systematic reviews included in The Cochrane Library is 2 years. However, it is unclear whether this interval is always appropriate. Whereas excessive updating wastes time and resources, insufficient updating allows out-of-date or incomplete evidence to guide clinical decision-making. We set out to determine, for Cochrane pregnancy and childbirth reviews, the frequency of updates, factors associated with updating, and whether updating frequency was appropriate. METHODOLOGY/PRINCIPAL FINDINGS: Cochrane pregnancy and childbirth reviews published in Issue 3, 2007 of the Cochrane Database of Systematic Reviews were retrieved, and data were collected from their original and updated versions. Quantitative changes were determined for one of the primary outcomes (mortality, or the outcome of greatest clinical significance). Potential factors associated with time to update were assessed using the Cox proportional hazard model. Among the 101 reviews in our final sample, the median time before the first update was 3.3 years (95% CI 2.7-3.8). Only 32.7% had been updated within the recommended interval of 2 years. In 75.3% (76/101), a median of 3 new trials with a median of 576 additional participants were included in the updated versions. There were quantitative changes in 71% of the reviews that included new trials (54/76): the median change in effect size was 18.2%, and the median change in 95% CI width was 30.8%. Statistical significance changed in 18.5% (10/54) of these reviews, but conclusions were revised in only 3.7% (2/54). A shorter time to update was associated with the same original review team at updating. CONCLUSIONS/SIGNIFICANCE: Most reviews were updated less frequently than recommended by Cochrane policy, but few updates had revised conclusions. Prescribed time to update should be reconsidered to support improved decision-making while making efficient use of limited resources

    Caesarean section without medical indications is associated with an increased risk of adverse short-term maternal outcomes: the 2004-2008 WHO Global Survey on Maternal and Perinatal Health

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    <p>Abstract</p> <p>Background</p> <p>There is worldwide debate about the appropriateness of caesarean sections performed without medical indications. In this analysis, we aim to further investigate the relationship between caesarean section without medical indication and severe maternal outcomes.</p> <p>Methods</p> <p>This is a multicountry, facility-based survey that used a stratified multistage cluster sampling design to obtain a sample of countries and health institutions worldwide. A total of 24 countries and 373 health facilities participated in this study. Data collection took place during 2004 and 2005 in Africa and the Americas and during 2007 and 2008 in Asia. All women giving birth at the facility during the study period were included and had their medical records reviewed before discharge from the hospital. Univariate and multilevel analysis were performed to study the association between each group's mode of delivery and the severe maternal and perinatal outcome.</p> <p>Results</p> <p>A total of 286,565 deliveries were analysed. The overall caesarean section rate was 25.7% and a total of 1.0 percent of all deliveries were caesarean sections without medical indications, either due to maternal request or in the absence of other recorded indications. Compared to spontaneous vaginal delivery, all other modes of delivery presented an association with the increased risk of death, admission to ICU, blood transfusion and hysterectomy, including antepartum caesarean section without medical indications (Adjusted Odds Ratio (Adj OR), 5.93, 95% Confidence Interval (95% CI), 3.88 to 9.05) and intrapartum caesarean section without medical indications (Adj OR, 14.29, 95% CI, 10.91 to 18.72). In addition, this association is stronger in Africa, compared to Asia and Latin America.</p> <p>Conclusions</p> <p>Caesarean sections were associated with an intrinsic risk of increased severe maternal outcomes. We conclude that caesarean sections should be performed when a clear benefit is anticipated, a benefit that might compensate for the higher costs and additional risks associated with this operation.</p

    Caesarean section in four South East Asian countries: reasons for, rates, associated care practices and health outcomes

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    Background: Caesarean section is a commonly performed operation on women that is globally increasing in prevalence each year. There is a large variation in the rates of caesarean, both in high and low income countries, as well as between different institutions within these countries. This audit aimed to report rates and reasons for caesarean and associated clinical care practices amongst nine hospitals in the four South East Asian countries participating in the South East Asia-Optimising Reproductive and Child Health in Developing countries (SEA-ORCHID) project. Methods: Data on caesarean rates, care practices and health outcomes were collected from the medical records of the 9550 women and their 9665 infants admitted to the nine participating hospitals across South East Asia between January and December 2005. Results: Overall 27% of women had a caesarean section, with rates varying from 19% to 35% between countries and 12% to 39% between hospitals within countries. The most common indications for caesarean were previous caesarean (7.0%), cephalopelvic disproportion (6.3%), malpresentation (4.7%) and fetal distress (3.3%). Neonatal resuscitation rates ranged from 7% to 60% between countries. Prophylactic antibiotics were almost universally given but variations in timing occurred between countries and between hospitals within countries. Conclusion: Rates and reasons for caesarean section and associated clinical care practices and health outcomes varied widely between the four South East Asian countries.Mario R Festin, Malinee Laopaiboon, Porjai Pattanittum, Melissa R Ewens, David J Henderson-Smart and Caroline A Crowther for The SEA-ORCHID Study Grou

    Impact of increasing capacity for generating and using research on maternal and perinatal health practices in South East Asia (SEA-ORCHID Project)

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    Writing committee: P. Lumbiganon, S. J. McDonald, M. Laopaiboon, T. Turner, S. Green, C. A. Crowther. The SEA-ORCHID Study Group consists of: Pisake Lumbiganon, Mario Festin, Jacqueline Ho, Hakimi Mohammad, David Henderson-Smart, Sally Green and Caroline Crowther. Educators and Fellows. AUSTRALIA: Jacki Short, Tari Turner, Ruth MartisBackground: Maternal and neonatal mortality and morbidity remain unacceptably high in many low and middle income countries. SEA-ORCHID was a five year international collaborative project in South East Asia which aimed to determine whether health care and health outcomes for mothers and babies could be improved by developing capacity for research generation, synthesis and use. Methods: Nine hospitals in Indonesia, Malaysia, the Philippines and Thailand participated in SEA-ORCHID. These hospitals were supported by researchers from three Australian centres. Health care practices and outcomes were assessed for 1000 women at each hospital both before and after the intervention. The capacity development intervention was tailored to the needs and context of each hospital and delivered over an 18 month period. Main outcomes included adherence to forms of care likely to be beneficial and avoidance of forms of care likely to be ineffective or harmful. Results: We observed substantial variation in clinical practice change between sites. The capacity development intervention had a positive impact on some care practices across all countries, including increased family support during labour and decreased perineal shaving before birth, but in some areas there was no significant change in practice and a few beneficial practices were followed less often. Conclusion: The results of SEA-ORCHID demonstrate that investing in developing capacity for research use, synthesis and generation can lead to improvements in maternal and neonatal health practice and highlight the difficulty of implementing evidence-based practice change.The SEA-ORCHID Study Group... [C. A. Crowther... Ruth Martis...

    A global reference for caesarean section rates (C-Model): a multicountry cross-sectional study.

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    OBJECTIVE: To generate a global reference for caesarean section (CS) rates at health facilities. DESIGN: Cross-sectional study. SETTING: Health facilities from 43 countries. POPULATION/SAMPLE: Thirty eight thousand three hundred and twenty-four women giving birth from 22 countries for model building and 10,045,875 women giving birth from 43 countries for model testing. METHODS: We hypothesised that mathematical models could determine the relationship between clinical-obstetric characteristics and CS. These models generated probabilities of CS that could be compared with the observed CS rates. We devised a three-step approach to generate the global benchmark of CS rates at health facilities: creation of a multi-country reference population, building mathematical models, and testing these models. MAIN OUTCOME MEASURES: Area under the ROC curves, diagnostic odds ratio, expected CS rate, observed CS rate. RESULTS: According to the different versions of the model, areas under the ROC curves suggested a good discriminatory capacity of C-Model, with summary estimates ranging from 0.832 to 0.844. The C-Model was able to generate expected CS rates adjusted for the case-mix of the obstetric population. We have also prepared an e-calculator to facilitate use of C-Model (www.who.int/reproductivehealth/publications/maternal_perinatal_health/c-model/en/). CONCLUSIONS: This article describes the development of a global reference for CS rates. Based on maternal characteristics, this tool was able to generate an individualised expected CS rate for health facilities or groups of health facilities. With C-Model, obstetric teams, health system managers, health facilities, health insurance companies, and governments can produce a customised reference CS rate for assessing use (and overuse) of CS. TWEETABLE ABSTRACT: The C-Model provides a customized benchmark for caesarean section rates in health facilities and systems
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