The use of an economical medium for the production of alkaline serine proteases by Bacillus licheniformis NH1

The present study is concerned with the selection of new economical media based on agricultural and marine-processing by-products for the production of alkaline proteases by Bacillus licheniformis NH1. Powders from different fish species were prepared and then tested as growth media at a concentration of 10 g/l for proteases production by NH1 strain. Powder prepared from whole Sardinelle was found to be the best substrate for the production of the alkaline protease. The NH1 strain exhibited a slightlygreater protease production (2927 U/ml) in medium containing only whole Sardinelle powder than that obtained in control medium (2800 U/ml). Proteases were produced even when strain NH1 was cultivated in medium containing only powder prepared from combined heads and viscera Sardinelle (CHVSP), about 2117 U/ml. Protease production was also carried out in media containing hulled grain of wheat, a by-product of semolina factories, as carbon source. Maximum activity (2517 U/ml) was achieved when the strain was grown in medium containing hulled grain of wheat (10 g/l), casein peptone (2 g/l), K2HPO4 (0.5 g/l) and KH2PO4 (0.5 g/l). Moreover, protease production was considerably enhanced when thestrain was grown in medium containing both hulled grain of wheat and CHVSP as carbon and nitrogen sources, respectively, (4771 U/ml). The study shows that hulled grain of wheat and powders from fishery by-products could be utilized as bacterial substrates for the production of alkaline proteases by B. licheniformis NH1

Parametric Study Of Friction Stir Spot Welding (FSSW) For Polymer Materials Case Of High Density Polyethylene Sheets: Experimental And Numerical Study

Friction stir spot welding (FSSW) is a very important part of conventional friction stir welding (FSW) which can be a replacement for riveted assemblies and resistance spot welding. This technique provides high quality joints compared to conventional welding processes. Friction stir spot welding (FSSW) is a new technology adopted to join various types of metals such as titanium, aluminum, magnesium. It is also used for welding polymer materials which are difficult to weld by the conventional welding process. In various industrial applications, high density polyethylene (HDPE) becomes the most used material. The parameters and mechanical properties of the welds are the major problems in the welding processes. In this paper, we have presented a contribution in finite element modeling of the friction stir spot welding process (FSSW) using Abaqus as a finite element solver. The objective of this paper is to study the HDPE plates resistance of stir spot welding joints (FSSW). First, we show the experimental tests results of high-density polyethylene (HDPE) plates assembled by friction stir spot welding (FSSW). Three-dimensional numerical modeling by the finite element method makes it possible to determine the best representation of the weld joint for a good prediction of its behavior. Comparison of the results shows that there is a good agreement between the numerical modeling predictions and the experimental results

Assessing the performance of a serological point-of-care test in measuring detectable antibodies against SARS-CoV-2

This study investigated the performance of a rapid point-of-care antibody test, the BioMedomics COVID-19 IgM/IgG Rapid Test, in comparison with a high-quality, validated, laboratory-based platform, the Roche Elecsys Anti-SARS-CoV-2 assay. Serological testing was conducted on 709 individuals. Concordance metrics were estimated. Logistic regression was used to assess associations with seropositivity. SARS-CoV-2 seroprevalence was 63.5% (450/709; 95% CI 59.8%-67.0%) using the BioMedomics assay and 71.9% (510/709; 95% CI 68.5%-75.2%) using the Elecsys assay. There were 60 discordant results between the two assays, all of which were seropositive in the Elecsys assay, but seronegative in the BioMedomics assay. Overall, positive, and negative percent agreements between the two assays were 91.5% (95% CI 89.2%-93.5%), 88.2% (95% CI 85.1%-90.9%), and 100% (95% CI 98.2%-100%), respectively, with a Cohen’s kappa of 0.81 (95% CI 0.78–0.84). Excluding specimens with lower (Elecsys) antibody titers, the agreement improved with overall, positive, and negative percent concordance of 94.4% (95% CI 92.3%-96.1%), 91.8% (95% CI 88.8%-94.3%), and 100% (95% CI 98.2%-100%), respectively, and a Cohen’s kappa of 0.88 (95% CI 0.85–0.90). Logistic regression confirmed better agreement with higher antibody titers. The BioMedomics COVID-19 IgM/IgG Rapid Test demonstrated good performance in measuring detectable antibodies against SARS-CoV-2, supporting the utility of such rapid point-of-care serological testing to guide the public health responses and vaccine prioritization. © 2022 Coyle et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Prevalence and factors associated with maternal and neonatal sepsis in sub-Saharan Africa: a systematic review and meta-analysis

ObjectivesThis study aimed to determine the prevalence and factors associated with maternal and neonatal sepsis in sub-Saharan Africa.MethodsThis systematic review and meta-analysis used the PRISMA guideline on sepsis data in sub-Saharan Africa. The bibliographic search was carried out on the following databases: Medline/PubMed, Cochrane Library, African Index Medicus, and Google Scholar. Additionally, the reference lists of the included studies were screened for potentially relevant studies. The last search was conducted on 15 October 2022. The Joanna Briggs Institute quality assessment checklist was applied for critical appraisal. Estimates of the prevalence of maternal and neonatal sepsis were pooled using a random-effects meta-analysis model. Heterogeneity between studies was estimated using the Q statistic and the I2 statistic. The funnel plot and Egger’s regression test were used to assess the publication bias.ResultsA total of 39 studies were included in our review: 32 studies on neonatal sepsis and 7 studies on maternal sepsis. The overall pooled prevalence of maternal and neonatal sepsis in Sub-Saharan Africa was 19.21% (95% CI, 11.46–26.97) and 36.02% (CI: 26.68–45.36), respectively. The meta-analyses revealed that Apgar score < 7 (OR: 2.4, 95% CI: 1.6–3.5), meconium in the amniotic fluid (OR: 2.9, 95% CI: 1.8–4.5), prolonged rupture of membranes >12 h (OR: 2.8, 95% CI: 1.9–4.1), male sex (OR: 1.2, 95% CI: 1.1–1.4), intrapartum fever (OR: 2.4, 95% CI: 1.5–3.7), and history of urinary tract infection in the mother (OR: 2.7, 95% CI: 1.4–5.2) are factors associated with neonatal sepsis. Rural residence (OR: 2.3, 95% CI: 1.01–10.9), parity (OR: 0.5, 95% CI: 0.3–0.7), prolonged labor (OR: 3.4, 95% CI: 1.6–6.9), and multiple digital vaginal examinations (OR: 4.4, 95% CI: 1.3–14.3) were significantly associated with maternal sepsis.ConclusionThe prevalence of maternal and neonatal sepsis was high in sub-Saharan Africa. Multiple factors associated with neonatal and maternal sepsis were identified. These factors could help in the prevention and development of strategies to combat maternal and neonatal sepsis. Given the high risk of bias and high heterogeneity, further high-quality research is needed in the sub-Saharan African context, including a meta-analysis of individual data.Systematic review registration: PROSPERO (ID: CRD42022382050)

SARS-CoV-2 seroprevalence in the urban population of Qatar: An analysis of antibody testing on a sample of 112,941 individuals

ABSTRACTBackgroundQatar has experienced a large SARS-CoV-2 epidemic. Our first objective was to assess the proportion of the urban population that has been infected with SARS-CoV-2, by measuring the prevalence of detectable antibodies. Our second objective was to identify predictors for infection and for having higher antibody titers.MethodsResidual blood specimens from individuals receiving routine and other clinical care between May 12-September 9, 2020 were tested for anti-SARS-CoV-2 antibodies. Associations with seropositivity and higher antibody titers were identified through regression analyses. Probability weights were applied in deriving the epidemiological measures.ResultsWe tested 112,941 individuals (∼10% of Qatar’s urban population), of whom 51.6% were men and 66.0% were 20-49 years of age. Seropositivity was 13.3% (95% CI: 13.1-13.6%) and was significantly associated with sex, age, nationality, clinical-care type, and testing date. The proportion with higher antibody titers varied by age, nationality, clinical-care type, and testing date. There was a strong correlation between higher antibody titers and seroprevalence in each nationality, with a Pearson correlation coefficient of 0.85 (95% CI: 0.47-0.96), suggesting that higher antibody titers may indicate repeated exposure to the virus. The percentage of antibody-positive persons with prior PCR-confirmed diagnosis was 47.1% (95% CI: 46.1-48.2%), severity rate was 3.9% (95% CI: 3.7-4.2%), criticality rate was 1.3% (95% CI: 1.1-1.4%), and fatality rate was 0.3% (95% CI: 0.2-0.3%).ConclusionsFewer than two in every 10 individuals in Qatar’s urban population had detectable antibodies against SARS-CoV-2 between May 12-September 9, 2020, suggesting that this population is still far from the herd immunity threshold and at risk from a subsequent epidemic wave.</jats:sec

Sleep Quality and Physical Activity as Predictors of Mental Wellbeing Variance in Older Adults during COVID-19 Lockdown:ECLB COVID-19 International Online Survey

Background. The COVID-19 lockdown could engender disruption to lifestyle behaviors, thus impairing mental wellbeing in the general population. This study investigated whether sociodemographic variables, changes in physical activity, and sleep quality from pre- to during lockdown were predictors of change in mental wellbeing in quarantined older adults. Methods. A 12-week international online survey was launched in 14 languages on 6 April 2020. Forty-one research institutions from Europe, Western-Asia, North-Africa, and the Americas, promoted the survey. The survey was presented in a differential format with questions related to responses "pre" and "during" the lockdown period. Participants responded to the Short Warwick-Edinburgh Mental Wellbeing Scale, the Pittsburgh Sleep Quality Index (PSQI) questionnaire, and the short form of the International Physical Activity Questionnaire. Results. Replies from older adults (aged &gt;55 years, n = 517), mainly from Europe (50.1%), Western-Asia (6.8%), America (30%), and North-Africa (9.3%) were analyzed. The COVID-19 lockdown led to significantly decreased mental wellbeing, sleep quality, and total physical activity energy expenditure levels (all p &lt; 0.001). Regression analysis showed that the change in total PSQI score and total physical activity energy expenditure (F-(2,F- 514) = 66.41 p &lt; 0.001) were significant predictors of the decrease in mental wellbeing from pre- to during lockdown (p &lt; 0.001, R-2: 0.20). Conclusion. COVID-19 lockdown deleteriously affected physical activity and sleep patterns. Furthermore, change in the total PSQI score and total physical activity energy expenditure were significant predictors for the decrease in mental wellbeing.</p

Correction: A Seroepidemiological Study of Serogroup A Meningococcal Infection in the African Meningitis Belt.

[This corrects the article DOI: 10.1371/journal.pone.0147928.]

Diversité des agricultures familiales

Dans un contexte d’interrogation sur les modèles agricoles et de profondes transformations des agricultures et des marchés, cet ouvrage s’attache à revisiter la diversité des formes familiales de production et leurs mutations de par le monde. Dès lors, l’analyse intègre les liens aux marchés, aux territoires et à l’Ailleurs — par le fait migratoire — les enjeux d’autonomie et de sécurité alimentaire, les stratégies de survie et d’accumulation ainsi que les formes d’action collective et politique. L’ouvrage est construit autour de dix-huit études de cas, menées dans les cinq continents. Elles ont toutes été conduites avec un cadre méthodologique, identique et original, inspiré du Sustainable Rural Livehoods (cadre d’identification des moyens de subsistance durables en milieu rural). Revisitée pour cet ouvrage, cette méthode d’observations et d’analyses permet aux auteurs de préciser finement « ce qui fait famille », d’analyser les adaptations du travail des actifs familiaux et les mettre en perspective avec le contexte territorial et les politiques publiques de chaque pays. Écrit à plusieurs mains, par un réseau de chercheurs, cet ouvrage contribue autant à l’approfondissement des savoirs scientifiques sur les agricultures familiales dans le monde qu’à la mise à l’épreuve d’un cadre méthodologique d’analyse et d’observations en milieu rural. Il vise un public de chercheurs, d’enseignants et d’étudiants, agronomes, économistes, sociologues et historiens. Les experts du développement agricole et rural y trouveront un grand intérêt. Plus largement, toute personne qui s’intéresse aux agricultures familiales et à leurs évolutions dans divers contextes sociaux trouvera avantage à cette lecture. Les chercheurs qui ont coordonné cet ouvrage sont agronomes, économistes et géographes, au Cirad ou à l’Inra où ils mènent des recherches sur les systèmes agricoles familiaux à des échelles locales, nationales ou internationales. Cet ouvrage est le fruit d’une démarche de recherche collective et partagée permettant à de nombreux scientifiques des pays du Sud d’exprimer la diversité des réalités agraires contemporaines. Certains coordinateurs ou auteurs de cet ouvrage ont également collaboré à Agricultures familiales et mondes à venir, titre paru en 2014 chez Quae. Ce livre est également disponible en anglais sous le titreDiversity of Family Farming Around the Worldauprès des éditions Springer -www.springer.co