17 research outputs found
Participant recall and understandings of information on biobanking and future genomic research: experiences from a multi-disease community-based health screening and biobank platform in rural South Africa.
BACKGROUND: Limited research has been conducted on explanations and understandings of biobanking for future genomic research in African contexts with low literacy and limited healthcare access. We report on the findings of a sub-study on participant understanding embedded in a multi-disease community health screening and biobank platform study known as 'Vukuzazi' in rural KwaZulu-Natal, South Africa. METHODS: Semi-structured interviews were conducted with research participants who had been invited to take part in the Vukuzazi study, including both participants and non-participants, and research staff that worked on the study. The interviews were transcribed, and themes were identified from the interview transcripts, manually coded, and thematically analysed. RESULTS: Thirty-nine individuals were interviewed. We found that the research team explained biobanking and future genomic research by describing how hereditary characteristics create similarities among individuals. However, recollection and understanding of this explanation seven months after participation was variable. The large volume of information about the Vukuzazi study objectives and procedures presented a challenge to participant recall. By the time of interviews, some participants recalled rudimentary facts about the genetic aspects of the study, but many expressed little to no interest in genetics and biobanking. CONCLUSION: Participant's understanding of information related to genetics and biobanking provided during the consent process is affected by the volume of information as well as participant's interest (or lack thereof) in the subject matter being discussed. We recommend that future studies undertaking biobanking and genomic research treat explanations of this kind of research to participants as an on-going process of communication between researchers, participants and the community and that explanatory imagery and video graphic storytelling should be incorporated into theses explanations as these have previously been found to facilitate understanding among those with low literacy levels. Studies should also avoid having broader research objectives as this can divert participant's interest and therefore understanding of why their samples are being collected
Independent and combined effects of improved water, sanitation, and hygiene, and improved complementary feeding, on child stunting and anaemia in rural Zimbabwe: a cluster-randomised trial.
BACKGROUND: Child stunting reduces survival and impairs neurodevelopment. We tested the independent and combined effects of improved water, sanitation, and hygiene (WASH), and improved infant and young child feeding (IYCF) on stunting and anaemia in in Zimbabwe. METHODS: We did a cluster-randomised, community-based, 2 × 2 factorial trial in two rural districts in Zimbabwe. Clusters were defined as the catchment area of between one and four village health workers employed by the Zimbabwe Ministry of Health and Child Care. Women were eligible for inclusion if they permanently lived in clusters and were confirmed pregnant. Clusters were randomly assigned (1:1:1:1) to standard of care (52 clusters), IYCF (20 g of a small-quantity lipid-based nutrient supplement per day from age 6 to 18 months plus complementary feeding counselling; 53 clusters), WASH (construction of a ventilated improved pit latrine, provision of two handwashing stations, liquid soap, chlorine, and play space plus hygiene counselling; 53 clusters), or IYCF plus WASH (53 clusters). A constrained randomisation technique was used to achieve balance across the groups for 14 variables related to geography, demography, water access, and community-level sanitation coverage. Masking of participants and fieldworkers was not possible. The primary outcomes were infant length-for-age Z score and haemoglobin concentrations at 18 months of age among children born to mothers who were HIV negative during pregnancy. These outcomes were analysed in the intention-to-treat population. We estimated the effects of the interventions by comparing the two IYCF groups with the two non-IYCF groups and the two WASH groups with the two non-WASH groups, except for outcomes that had an important statistical interaction between the interventions. This trial is registered with ClinicalTrials.gov, number NCT01824940. FINDINGS: Between Nov 22, 2012, and March 27, 2015, 5280 pregnant women were enrolled from 211 clusters. 3686 children born to HIV-negative mothers were assessed at age 18 months (884 in the standard of care group from 52 clusters, 893 in the IYCF group from 53 clusters, 918 in the WASH group from 53 clusters, and 991 in the IYCF plus WASH group from 51 clusters). In the IYCF intervention groups, the mean length-for-age Z score was 0·16 (95% CI 0·08-0·23) higher and the mean haemoglobin concentration was 2·03 g/L (1·28-2·79) higher than those in the non-IYCF intervention groups. The IYCF intervention reduced the number of stunted children from 620 (35%) of 1792 to 514 (27%) of 1879, and the number of children with anaemia from 245 (13·9%) of 1759 to 193 (10·5%) of 1845. The WASH intervention had no effect on either primary outcome. Neither intervention reduced the prevalence of diarrhoea at 12 or 18 months. No trial-related serious adverse events, and only three trial-related adverse events, were reported. INTERPRETATION: Household-level elementary WASH interventions implemented in rural areas in low-income countries are unlikely to reduce stunting or anaemia and might not reduce diarrhoea. Implementation of these WASH interventions in combination with IYCF interventions is unlikely to reduce stunting or anaemia more than implementation of IYCF alone. FUNDING: Bill & Melinda Gates Foundation, UK Department for International Development, Wellcome Trust, Swiss Development Cooperation, UNICEF, and US National Institutes of Health.The SHINE trial is funded by the Bill & Melinda Gates Foundation (OPP1021542 and OPP113707); UK Department for International Development; Wellcome Trust, UK (093768/Z/10/Z, 108065/Z/15/Z and 203905/Z/16/Z); Swiss Agency for Development and Cooperation; US National Institutes of Health (2R01HD060338-06); and UNICEF (PCA-2017-0002)
Water quality effects on a sulfidic PGM ore: Implications for froth stability and gangue management
Polysaccharide depressants play a crucial role in the flotation of sulfidic PGM bearing ores as they prevent naturally floatable gangue (NFG) from reporting to the concentrate. This action is regarded as critically important because less dilution of the concentrate means lower costs for downstream processes. However, abnormal water conditions such as high concentrations of ions in the flotation system can modify the selectivity of these depressants. It is well known that the existence of selected electrolytes in water can alter the behaviour of some polysaccharide depressants by enhancing their adsorption onto gangue minerals and thereby prevent naturally floatable gangue from moving into the froth phase. Concurrently these same electrolytes may enhance frothability owing to their stabilising effect on the bubbles within the system. Plant water at various ionic strengths was investigated against sodium carboxymethyl cellulose (CMC) dosages in order to understand electrolyte-depressant interactive effects during the flotation of a Merensky ore in a batch flotation cell, using entrainment, rate of NFG recovery, and total gangue recovery as proxies. The study showed that the NFG recovery per unit mass of water decreased with increasing ionic strength at all CMC dosages, however the total amount of gangue reporting to the concentrate increased with increasing ionic strength at all CMC dosages. Thus, this paper considers the effects of both ionic strength and CMC dosage within flotation. It further investigates whether any interactive effects exist between froth stability and entrainment when considered simultaneously
Perspectives from literature on the influence of inorganic electrolytes present in plant water on flotation performance
The interaction of inorganic electrolytes with reagents in the flotation of sulphidic PGM bearing ores is not well explored. It has been shown that specific inorganic electrolytes such as Ca2+ and SO42- can affect the wettability of gangue minerals. These could also hinder the adsorption of collectors onto valuable minerals and concurrently enhance or retard froth stability. This presents a challenge as regards understanding what the overarching or controlling mechanisms of interaction between electrolytes, reagents and minerals are as well as predicting how flotation performance will be affected. This review shows that studies in literature have simplified the question of electrolyte-reagent-mineral interactions and that current approaches have not provided fundamental solutions to the challenge of water quality. It is proposed that the complexity of the flotation system requires an in-depth knowledge of the individual electrolyte-reagent-mineral interactions so as to establish whether there are any dominant or synergistic interactions. Such in-depth knowledge should enable the development of pulp chemistry control measures against water quality variations in flotation
A fundamental study considering specific ion effects on the attachment of sulfide minerals to air bubbles
| openaire: EC/H2020/730480/EU//ITERAMSBubble-particle attachment is one of the most fundamental sub-processes in froth flotation. It is of critical importance in achieving the separation of value from non-value. This sub-process is affected by many factors such as the chemistry of the pulp, action of the reagents, hydrodynamics and operational factors. Understanding the effects of these factors on bubble-particle attachment is thus crucial as they may in turn affect the mineral recoveries attained. With the current drive towards zero effluent discharge on mineral concentrators water quality is an important factor to understand as it can change the pulp chemistry and subsequently affect mineral recoveries. This study thus considers the effect of specific ions found in process water on the bubble-particle attachment of chalcopyrite and galena. Adsorption studies and zeta potential measurements were conducted to interpret the outcomes of the bubble-particle attachment tests. Pulps containing Ca2+ resulted in lower bubble-particle attachment probability and recovery of galena and chalcopyrite. Adsorption studies complemented the bubble-particle attachment findings well and showed that in Ca2+ containing waters, less xanthate was adsorbed on both the chalcopyrite and galena surfaces. The zeta potential measurements showed an increase in mineral potential with Ca2+ containing salts compared to the very negative mineral potential in NaNO3. This work provides evidence of the passivation of the mineral surface with Ca2+; which hindered the adsorption of xanthate on the mineral surface in Ca2+ containing solutions and subsequently resulted in poor bubble-particle attachment.Peer reviewe
Fundamental and flotation techniques assessing the effect of water quality on bubble-particle attachment of chalcopyrite and galena
| openaire: EC/H2020/730480/EU//ITERAMS Funding Information: This work is financed by the National Research Foundation of South Africa (NRF) [Grant number 103641] and this project has received funding from the European Union H2020 programme under grant agreement No 730480. Any opinion, finding and conclusion or recommendation expressed in this material is that of the authors and the NRF does not accept any liability in this regard. Further the financial and technical contributions from the South African Minerals to Metals Research Institute (SAMMRI) is also acknowledged. Publisher Copyright: © 2021 The Author(s) Copyright: Copyright 2021 Elsevier B.V., All rights reserved.Bubble-particle attachment has been studied in the most fundamental way from as early as 1934 by bringing a bubble into contact with a flat mineral surface and since then, techniques measuring this interaction have advanced. Water quality within flotation will impact the bubble particle attachment and as more operations recycle their water on site, an understanding of this process becomes vital. This study uses an Automated Contact Time Apparatus (ACTA) to assess the effect of water quality on bubble-particle attachment of selected sulfide minerals; galena and chalcopyrite, from a fundamental perspective. Classical microflotation tests are complemented with collector adsorption and mineral potential under degrading water quality to validate the ACTA and gain an understanding of the effect of water quality on bubble-particle attachment as well as subsequent flotation. This investigation showed that the results from the ACTA qualitatively showed similar trends as that of the classical microflotation technique for measuring floatability, however the quantitively these methods showed very different results. Due to the dynamic nature of the microflotation technique it may be assumed that plant recovery will resemble the results from this technique closer than that of the ACTA. Furthermore, this investigation showed an increase in zeta potential of both minerals as the concentration of inorganic electrolytes in the water increased. It can thus be speculated that the increase in bubble-particle attachment with increasing ionic strength of synthetic plant water may be attributed to electrical double layer compression and particle agglomeration.Peer reviewe
Isisekelo Sempilo 2x2 factorial randomised controlled trial of the effectiveness of integrating HIV prevention within sexual reproductive health (SRH) services with or without peer support amongst adolescents and young adults in rural KwaZulu-Natal
Background: approximately 200,000 South Africans acquired HIV in 2021 despite universal HIV test and treat (UTT) and Pre-Exposure Prophylaxis (PrEP).Methods: we conducted a 2x2 factorial open label randomised controlled trial. N=3000 potentially eligible 16-29-year-olds, randomly sampled from a population surveillance area in a mostly rural part of KwaZulu-Natal, were randomised to one of 4 arms: 1) enhanced Standard of Care (SoC): access to mobile youth-friendly services for differentiated HIV prevention (condoms, UTT, PrEP if eligible); 2) Sexual and Reproductive Health (SRH): baseline self-collected specimens for sexually transmitted infection testing and referral to differentiated HIV prevention services; 3) Peer-support: referral to a peer navigator for support, condom provision and facilitation of attendance for differentiated HIV prevention services; 4) SRH + peer-support. Co-primary effectiveness outcomes were: 1) linkage to differentiated HIV prevention services within 60 days of enrolment; 2) transmissible HIV (HIV viral load ≥400 copies/mL) measured from dried blood spots (DBS) at 12 months. 3) the proportion of sampled individuals who consented to participation and gave a DBS for HIV testing at 12 months. Logistic regression was used for analyses, adjusted for age, sex and rural/peri-urban area.Findings: between March 2020 and August 2022, 1743/2301(76%) eligible individuals were enrolled, with a 12-month DBS collected from 1168 (67%). Baseline characteristics and 12-month outcome ascertainment were similar by arm. 755 (43.3%) linked to services by 60 days; SRH increased linkage (aOR 1.68;95%CI=1.39-2.04) but peer-support had no effect. At 12 months, 227 (19%) tested ELISA-positive for HIV, of whom 41 (18%) had a viral load ≥400 copies/ml. The overall prevalence of transmissible HIV was 3.5%. There was no evidence of an effect of either intervention on transmissible HIV (main effects: SRH aOR 1.12; 95%CI=0.60-2.11; peer-support aOR 1.03; 95%CI=0.55-1.94). Interpretation: in this representative sample of adolescents and youth in a mostly rural area of South Africa, STI testing and SRH (but not peer support) increased uptake of differentiated HIV prevention. While the UNAIDS target of 90:90:90 was exceeded, neither SRH nor peer support showed evidence of reducing transmissible HIV