ROCS

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Now showing 1 - 20 of 78
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    A compact acoustic spanner to rotate macroscopic objects
    E Toninelli; Mitchell Cox; Graham M. Gibson; Stuart D. Brown; Matthew P. Edger; Andrew Forbes; M Padgett
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    Antibacterial and Anticancer Activity and Untargeted Secondary Metabolite Profiling of Crude Bacterial Endophyte Extracts from Crinum macowanii Baker Leaves
    (Hindawi, 2020-12-10) T Sebola; N Uche-Okereafor; L Mekuto; Maya Makatini; E Green; Vuyo Mavumengwana
    This study isolated and identified endophytic bacteria from the leaves of Crinum macowanii and investigated the potential of the bacterial endophyte extracts as antibacterial and anticancer agents and their subsequent secondary metabolites. Ethyl acetate extracts from the endophytes and the leaves (methanol: dichloromethane (1 : 1)) were used for antibacterial activity against selected pathogenic bacterial strains by using the broth microdilution method. The anticancer activity against the U87MG glioblastoma and A549 lung carcinoma cells was determined by the MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxy-phenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay. Bacterial endophytes that were successfully isolated from C. macowanii leaves include Raoultella ornithinolytica, Acinetobacter guillouiae, Pseudomonas sp., Pseudomonas palleroniana, Pseudomonas putida, Bacillus safensis, Enterobacter asburiae, Pseudomonas cichorii, and Arthrobacter pascens. Pseudomonas cichorii exhibited broad antibacterial activity against both Gram-negative and Gram-positive pathogenic bacteria while Arthrobacter pascens displayed the least MIC of 0.0625 mg/mL. Bacillus safensis crude extracts were the only sample that showed notable cell reduction of 50% against A549 lung carcinoma cells at a concentration of 100 mu g/mL. Metabolite profiling of Bacillus safensis, Pseudomonas cichorii, and Arthrobacter pascens crude extracts revealed the presence of known antibacterial and/or anticancer agents such as lycorine (1), angustine (2), crinamidine (3), vasicinol (4), and powelline. It can be concluded that the crude bacterial endophyte extracts obtained from C. macowanii leaves can biosynthesize bioactive compounds and can be bioprospected for medical application into antibacterial and anticancer agents.
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    Carbon Encapsulated Ternary MnNiCo Oxide Nanoparticles as Electrode Materials for Energy Storage Applications
    (Wiley, 2020-12) Tarekegn Heliso Dolla; Isiaka A. Lawal; David Billing; K Pruessner; Patrick Ndungu; Dolla, TH; Lawal, IA; Billing, DG; Pruessner, k; Ndungu, P
    Ternary transition metal oxides are promising advanced materials for use as electrode components in electrochemical energy storage systems. However, low electronic/ionic conductivity hinder practical applications. In this study, ternary Mn-Ni-Co oxide nanoparticles were encapsulated in carbon nanosheets, to improve the electrical conductivity and surface area. When tested as supercapacitor electrodes, the materials exhibited specific capacity of 91.2 mAh g(-1)at a current density of 1 A g(-1)in 2 M KOH. Moreover, after 3000 cycles the composite achieved a specific capacity of 74.6 mAh g(-1)at a current density of 6 A g(-1)and high capacitance retention of 96.4 %.
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    Challenges in recruiting children to a multidrugresistant TB prevention trial
    S Purchase; E Batist; N Mmile; S Nkosi; J Workman; Neil Martinson; Lee Fairlie; H. S. Schaaf; et al et al
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    Classical Cardiovascular Risk Factors and HIV are Associated With Carotid IntimaMedia Thickness in Adults From SubSaharan Africa Findings From H3Africa AWIGen Study
    (2019-06-07) Boua P; Ali S; Soo C
    Background-—Studies on the determinants of carotid intima-media thickness (CIMT), a marker of sub-clinical atherosclerosis, mostly come from white, Asian, and diasporan black populations. We present CIMT data from sub-Saharan Africa, which is experiencing a rising burden of cardiovascular diseases and infectious diseases. Methods and Results-—The H3 (Human Hereditary and Health) in Africa’s AWI-Gen (African-Wits-INDEPTH partnership for Genomic) study is a cross-sectional study conducted in adults aged 40 to 60 years from Burkina Faso, Kenya, Ghana, and South Africa. Cardiovascular disease risk and ultrasonography of the CIMT of right and left common carotids were measured. Multivariable linear and mixed-effect multilevel regression modeling was applied to determine factors related to CIMT. Data included 8872 adults (50.8% men), mean age of 50 6 years with age- and sex-adjusted mean ( SE) CIMT of 640 123lm. Participants from Ghana and Burkina Faso had higher CIMT compared with other sites. Age (b = 6.77, 95%CI [6.34–7.19]), body mass index (17.6[12.5–22.8]), systolic blood pressure (7.52[6.21–8.83]), low-density lipoprotein cholesterol (5.08[2.10–8.06]) and men (10.3[4.75– 15.9]) were associated with higher CIMT. Smoking was associated with higher CIMT in men. High-density lipoprotein cholesterol (12.2 [17.9– 6.41]), alcohol consumption (–13.5 [19.1–7.91]) and HIV (8.86 [15.7–2.03]) were inversely associated with CIMT. Conclusions-—Given the rising prevalence of cardiovascular diseases risk factors in sub-Saharan Africa, atherosclerotic diseases may become a major pan-African epidemic unless preventive measures are taken particularly for prevention of hypertension, obesity, and smoking. HIV-specific studies are needed to fully understand the association between HIV and CIMT in sub-Saharan Africa
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    Determining immunological correlates of protection against group B streptococcus colonization in pregnant women
    (2016) Kwatra, Gaurav
    Introduction: Maternal recto-vaginal colonization with Group B Streptococcus (GBS) is the major risk factor for invasive GBS disease in newborn’s. Maternal vaccination against GBS during pregnancy may prevent or reduce subsequent recto-vaginal colonization in women, which could lower fetal/newborn exposure to GBS and contribute to reducing GBS associated infections during early infancy. In this study we determined the immunological correlates of protection against GBS colonization in black African pregnant women. Methods: We compared GBS serotype-specific serum IgG, mucosal IgG, mucosal IgA and cellular immune responses in relation to GBS rectovaginal acquisition and clearance in pregnant women from 20 to 37+ weeks of gestational age. Furthermore, we also evaluated different media for isolation of GBS from vaginal and rectal swabs. Results: The prevalence of recto-vaginal GBS colonization was 33.0%, 32.7%, 28.7% and 28.4% at 20-25 weeks, 26-30 weeks, 31-35 weeks and 37+ weeks of gestational age, respectively. The most common identified serotypes were Ia (39.2%), III (32.8%) and V (12.4%). The cumulative overall recto-vaginal acquisition rate of new serotypes during the study was 27.9%, including 11.2%, 8.2% and 4.3% for serotypes Ia, III and V, respectively. The recovery of GBS from rectal swabs was significantly higher from direct plating on chromogenic medium (p<0.0001) than from selective broth method. New-acquisition of GBS was inversely correlated with serotype-specific serum IgG concentration for serotype III (p=0.009) and OPA titer for serotype Ia and III (p<0.001 for both) at time of enrolment. Serum IgG concentration significantly associated with protection against recto-vaginal acquisition of the homotypic serotype was ≥1 μg/ml for serotype V (p=0.039), ≥3 μg/ml for serotype Ia (p=0.043) and III (p=0.023). Mucosal IgG correlated significantly with serum IgG with Rho values of 0.839, 0.621 and 0.426 (all p<0.001) for serotype Ia, III and V, respectively. The clearance of serotype-specific GBS recto-vaginal colonization during pregnancy was positively associated with presence of homotypic capsular ELISpot IFN-γ positivity for serotype III (p=0.008) Conclusion: Maternal GBS colonization could be used as end point to evaluate efficacy of GBS vaccine. A serotype-specific capsular polysaccharide based GBS vaccine able to elicit both humoral and cell-mediated capsular immune responses could confer protection against EOD by reducing the exposure of the newborn’s to GBS colonization during the peri-partum period.
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    Does expanding fiscal space lead to improved funding of the health sector in developing countries?: lessons from Kenya, Lagos State (Nigeria) and South Africa
    (Taylor & Francis, 2018-05-16) Doherty, Jane Tanya; Kirigia, Doris; Okoli, Chijioke; Chuma, Jane; Ezumah, N; Ichoku, Hyacinth; Hanson, Kara; McIntyre, Diane
    This article examines whether increased tax revenue in the three territories of Kenya, Lagos State (Nigeria) and South Africa was accompanied by improved resource allocation to their public health sectors, and explores the reasons underlying the observed trends.
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    Does having children affect womens entrepreneurship decision Evidence from Nigeria
    (SpringerLink, 2019-09) Ajefu, J. B.
    This paper investigates the impact of fertility on women’s entrepreneurship decision in Nigeria, using the 2008 and 2013 cross-sectional Demographic Health Surveys data. In order to mitigate the potential endogeneity associated with fertility decision, the study explores an exogenous variation in family size using twin births in an instrumental variable (IV) analysis. Both the Ordinary Least Squares (OLS) and Two-Stage Least Squares (2SLS) estimate show that having children is positively associated with women’s entrepreneurship decision, and there are heterogeneous effects across the subsamples by women’s age. The results of this study are robust to using the number of children younger than age five in the home as an alternative definition of fertility.
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    Does village chickenkeeping contribute to young childrens diets and growth A longitudinal observational study in rural Tanzania
    (MDPI, 2018-11-19) J de Bruyn; PC Thomson; I Darnton-Hill; Brigitte Bagnol; W Maulaga; RG Alders
    There is substantial current interest in linkages between livestock-keeping and human nutrition in resource-poor settings. These may include benefits of improved diet quality, through animal-source food consumption and nutritious food purchases using livestock-derived income, and hazards of infectious disease or environmental enteric dysfunction associated with exposure to livestock feces. Particular concerns center on free-roaming chickens, given their proximity to children in rural settings, but findings to date have been inconclusive. This longitudinal study of 503 households with a child under 24 months at enrolment was conducted in villages of Manyoni District, Tanzania between May 2014, and May 2016. Questionnaires encompassed demographic characteristics, assets, livestock ownership, chicken housing practices, maternal education, water and sanitation, and dietary diversity. Twice-monthly household visits provided information on chicken numbers, breastfeeding and child diarrhea, and anthropometry was collected six-monthly. Multivariable mixed model analyses evaluated associations between demographic, socioeconomic and livestock-associated variables and (a) maternal and child diets, (b) children’s height-for-age and (c) children’s diarrhea frequency. Alongside modest contributions of chicken-keeping to some improved dietary outcomes, this study importantly (and of substantial practical significance if confirmed) found no indication of a heightened risk of stunting or greater frequency of diarrhea being associated with chicken-keeping or the practice of keeping chickens within human dwellings overnight.
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    Edible backyards: climate change and urban food insecurity in Africa
    (BioMed Central, 2018) Nkrumah, Bright
    Background: Food insecurity is continuously seen as a major problem in Africa, and as a challenge confronting millions of Africa’s urban population. Although some city residents produce their own food and, therefore, are food secured, others continuously fnd it difcult to access arable land in order to keep animals or cultivate crops. Climate change, in addition, seems to worsen the food insecurity situation of the region’s urban population, especially in the face of drought and fooding waters. To this end, this study recommends that urban agriculture (UA) is well positioned to mitigate the adverse efect of climate change and improve food security. Results: The study found that the current problem posed by climate change to Africa’s urban food security is expected to worsen. Many urban populations are at risk of becoming victims of climate change through severe food supply problems caused by foods, droughts and hailstorms that afect food production in the hinterlands. African urban population has a role to play in fnding appropriate solution to sustain food security, especially through UA. Conclusion: The study concludes that African governments should endeavour to create the necessary conducive environment to encourage urban residents to engage in animal husbandry and food production.
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    An Emperical Study on the Predictors of the Perceived Quality of Learning at Institutions of Higher Education 2D Model Approach
    (2019) Mmatlou Matlakala; Norman Chiliya; Tinashe Chuchu; Tinashe Ndoro
    The purpose of the present study was to conduct an empirical investigation into the predictors of the perceived quality of learning at institutions of higher education from the student’s perspective. The research was based on a conceptual model consisting of six proposed hypotheses. A quantitative study that utilised the survey methodology was adopted is it was imperative to obtain objective findings that would be later used for statistical purposes. In terms of selection of suit-able participants for the study, non-probability sampling, a form of convenience sampling was adopted. Perceptions of students regarding the quality of education were tested empirically. The 2 D Model approach was adopted to investigate this phenomenon. Data was collected from a total of 300 students from a selected university in South Africa. To analyse the data SPSS 24 and AMOS 24 were utilised for descriptive statistics and hypotheses testing respectively. A university’s reputation and the geographic region a student originated from were observed as having the greatest influence on those students’ perception of quality of education that a higher education institution provided.
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    Epidemiology of maxillofacial fractures at two maxillofacial units in South Africa
    (South African Dental Association, 2018-04) Mogajane, Brampie; Mabongo, Mzubanzi
    This article compares epidemiologic characteristics of maxillofacial fractures seen in patients presenting at Charlotte Maxeke Johannesburg Academic Hospital (CMJAH) with those seen at Polokwane – Mankweng Hospital Complex (PMHC).
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