AAS Open Research最新文献

Background: The removal of textile wastes is a priority due to their mutagenic and carcinogenic properties.  In this study, bismuth oxyhalide was used in the removal of methylene blue (MB) which is a textile waste. The main objective of this study was to develop and investigate the applicability of a bismuth oxyhalide (BiOBr _zI _(1-z)) solid solutions in the photodegradation of MB under solar and ultraviolet (UV) light irradiation. Methods: Bismuth oxyhalide (BiOBr _zI _(1-z)) (0 ≤ z ≤ 1) materials were successfully prepared through the hydrothermal method. Brunauer-Emmett-Teller (BET), transmission electron microscope (TEM), X-ray diffractometer (XRD), and scanning electron microscope (SEM) were used to determine the surface area, microstructure, crystal structure, and morphology of the resultant products. The photocatalytic performance of BiOBr _zI _(1-z) materials was examined through methylene blue (MB) degradation under UV light and solar irradiation. Results: The XRD showed that BiOBr _zI _(1-z) materials crystallized into a tetragonal crystal structure with (102) peak slightly shifting to lower diffraction angle with an increase in the amount of iodide (I ^-). BiOBr _0.6I _0.4 materials showed a point of zero charge of 5.29 and presented the highest photocatalytic activity in the removal of MB with 99% and 88% efficiency under solar and UV irradiation, respectively. The kinetics studies of MB removal by BiOBr _zI _(1-z) materials showed that the degradation process followed nonlinear pseudo-first-order model indicating that the removal of MB depends on the population of the adsorption sites. Trapping experiments confirmed that photogenerated holes (h ⁺) and superoxide radicals ( ^•O ₂ ^-) are the key species responsible for the degradation of MB. Conclusions : This study shows that bismuth oxyhalide materials are very active in the degradation of methylene blue dye using sunlight and thus they have great potential in safeguarding public health and the environment from the dye's degradation standpoint. Moreover, the experimental results agree with nonlinear fitting.

Background: There are low levels of research productivity among Higher Education Institutions (HEIs) in Africa, a situation that is likely to compromise the development agenda of the continent if not addressed. We conducted a systematic literature review to synthesize evidence of the factors associated with research productivity in HEIs in Africa and the researchers' motives for research. Methods: We identified 838 publications related to research productivity in HEIs in Africa from various databases, from which we included 28 papers for review. The inclusion criteria were that (i) the paper's primary focus was on factors associated with research productivity, and motivations of doing research among faculty members in Africa; (ii) the setting was the HEIs in Africa; (iii) the type of publication was peer-reviewed papers and book chapters based on primary or secondary data analysis; and (iv) the language was English or French. Essays, opinions, blogs, editorials, reviews, and commentaries were excluded. Results: Most of the studies operationalized research productivity as either journal publications or conference proceedings. Both institutional and individual factors are associated with the level of research productivity in HEIs in Africa. Institutional factors include the availability of research funding, level of institutional networking, and the degree of research collaborations, while individual factors include personal motivation, academic qualifications, and research self-efficacy. Conclusions: Deliberate efforts in HEIs in Africa that addressed both individual and institutional barriers to research productivity are promising. This study recommends that the leadership of HEIs in Africa prioritizes the funding of research to enable researchers to contribute to the development agenda of the continent. Moreover, HEIs should build institutional support to research through the provision of research enabling environment, policies and incentives; strengthening of researchers' capabilities through relevant training courses, mentorship and coaching; and embracing networking and collaboration opportunities.

Background: The need for competent research managers and administrators (RMAs) has increased due to the complexity in managing research projects between disparate and international partners. To facilitate the creation of robust training and professional development programmes it is essential to first understand the status quo. A collaborative project, Sustainable Management and Administration for Research: Training across the project Lifecycle (SMARTLife), made up of RMAs from South Africa, Zimbabwe and the United Kingdom (UK) developed a set of competencies to conduct an RMA competency-based training needs assessment scoping tool. Method: Nine areas were identified: Equitable partnership; Finance Management; Project Management; Monitoring and Evaluation; Reporting and Communications; Equity, Diversity & Inclusion; Training and Capacity Development; Impact a& Sustainability; and Ethical, Social, Legal a& Social Implications.  Tasks for each competency area were identified to develop an scoping tool that had 168 data collection points. The tool was advertised through press releases, mailing lists and social media. Results:  108 responses were obtained:  with 49% from 15 Africa countries/the remainder from the UK. The UK (71%) had more permanent RMA staff members compared to Africa (39%). There were more respondents in Africa with the title of Research Manager/Coordinator(p=0.0132) compared to the UK where most of the RMAs were employed as Finance/Contract officers. 60% of respondents from the UK had more than three years experience while only 35% from Africa had experience. While most RMAs had formal higher education qualifications, their training was not in research management and administration, which requires a diverse range of skills. Confidence in specific tasks varied between the UK and Africa whereas collaborative partnerships challenges and enablers were similar. Conclusion This work highlights differences in RMA training and experience RMA  between Africa and UK, this work could inform much needed competency-based training for RMAs and partnership strategies that aid mutual-learning.

Background High-risk sexual behaviors(HRSBs) among young adults are key risk for Sexually Transmitted Infections(STIs), HIV and unplanned pregnancies. WHO has identified the 15-24years age-group as high-risk for STIs. Students at Higher Learning Institutions(HLIs) may be at higher risk because they are free of immediate parental-supervision, are a transient migratory population, probably at peak-years of sexual activity.  In Tanzania, information is limited on sexual and preventive behaviours among young adults in HLIs. We describe risky sexual behaviours and preventive practices among young adults attending HLIs in Mbeya-Tanzania. Methods We conducted a cross-sectional study from March2019 to January2020 among randomly selected students aged 18-24years enrolled in HLIs within Mbeya.  Probability proportional to size was used to determine total student number from each HLI. We used a self-administered questionnaire to collect information on sexual health education, activity, behaviour and STI knowledge. Results Total of 504students were enrolled with mean age of 21.5(SD 1.74)years. Total of 446(88.5%) students reported ever having had sex. Mean-age at first sex was 18.4years and 9.9% reported sexual debut <15years. A higher proportion of male students(57%) reported sexual debut with non-steady partners than females(37.9%). Lack of condom use at sexual debut was reported by 52% of the participants. Consistent condom use during past 4-weeks was reported at 33% and 16.5% among males and females, respectively. About 1 in 10 students reported forced sex by someone they were dating. Sex under the influence of alcohol was reported by 24% of the students.  Nearly 8 in 10 (78.7%) students have heard of STIs, but only 16% were aware STIs can be asymptomatic.  Conclusion STI prevention programs need to recognize young adults in HLIs as at-risk population; and advocate targeted messages to minimize risk to acquiring STIs, counseling and support for those experiencing sexual violence, promote condom use and safer-sex negotiation skills.

Background: The recovery of phenolic compounds is seen as an arduous task because phenolic compounds are available as free aglycones, as sugar or ester conjugates, or as polymers with several monomeric components. This study looks at the optimization of factors that affect the efficiency for the extraction of phenolic compounds from the stem-bark of Funtumia elastica.

Methods: Five independent variables (solvent concentration, time, the temperature, solid-liquid ratio, and pH) of the extraction process were selected. Single factor analysis as well as the response surface method was used to evaluate the impact of the selected factors on the total phenolic content. The effect of the extraction factors on the phenolic content was tested for its statistical significant (p <0.05). For the response surface method, a five/factor, five/level central composite design was used, and a fitted second-order polynomial regression model equation was used to show how the extraction parameters affected the total phenolic recovery.

Results: The predicted value (R² of 0.5917) agreed with the adjusted value (R² of 0.7707). The residuals for response predictions were less than 5%. The optimal factors for the extraction were ethanol concentration of 75.99% v/v, extraction time of 193.86 minutes, temperature of 63.66°C, pH of 5.62, and solid-liquid ratio of 1:21.12 g/mL. Actual overall content of the phenolic compounds was validated at 82.83 ± 3.335 mg gallic acid equivalent (GAE) /g weight of extract, which agreed with the predicted response of 89.467 mg GAE/g of the dried extract under the optimal factors.

Conclusions: The rich phenolic content of stem-bark of Funtumia elastica points to its potential as a functional medicinal product to alleviate diseases caused by oxidative stress such as asthma, breathing disorders, inflammation, and cardiovascular diseases. The results obtained indicate that, the studied optimal conditions support effective phenolics extraction of Funtumia elastica.

Background: Cancer is a highly stigmatized illness associated with profound adverse impact on communities, families and diagnosed individuals. Notwithstanding extensive theorizing since Erving Goffman's classical contributions, health stigma is well explicated in context-specific and situated analysis. The current study explored the manifestations of self and enacted stigma among 20 selected people diagnosed with cancer from rural and urban Zimbabwe, who sought quaternary level of health care services in the capital, Harare. Methods: Phenomenological methodology was enlisted to capture intimate expressions of stigma as expressed about, and by people diagnosed with cancer. Data collection methods used includes semi-structured interviews, key informant interviews and focus group discussions. A semi-structured in-depth interview guide, focus group discussion guide and a key informant interview guide were the tools used to collect the data. Results: The study identified five themes of stigma, indicating pronounced, complex and multiple catalogues of stigma embedded in the existing socio-cultural milieu. Conclusions: This study stands to offer invaluable conceptual schemas and empirical insights on health-related stigma, and may aid in nursing and in the design of educational programs meant to combat health stigma.