HIV risk and prevention among men who have sex with men in rural South Africa

Rural South African men who have sex with men (MSM) are likely to be underserved in terms of access to relevant healthcare and HIV prevention services. While research in urban and peri-urban MSM populations has identified a range of factors affecting HIV risk in South African MSM, very little research is available that examines HIV risk and prevention in rural MSM populations. This exploratory study begins to address this lack by assessing perceptions of HIV risk among MSM in rural Limpopo province. Using thematic analysis of interview and discussion data, two overarching global themes that encapsulated participants’ understandings of HIV risk and the HIV risk environment in their communities were developed. In the first theme, “community experience and the rural social environment”, factors affecting HIV risk within the broad risk environment were discussed. These included perceptions of traditional value systems and communities as homophobic; jealousy and competition between MSM; and the role of social media as a means of meeting other MSM. The second global theme, “HIV/AIDS knowledge, risk and experience”, focused on factors more immediately affecting HIV transmission risk. These included: high levels of knowledge of heterosexual HIV risk, but limited knowledge of MSM-specific risk; inconsistent condom and lubricant use; difficulties in negotiating condom and lubricant use due to uneven power dynamics in relationships; competition for sexual partners; multiple concurrent sexual partnerships; and transactional sex. These exploratory results suggest that rural South African MSM, like their urban and peri-urban counterparts, are at high risk of contracting HIV, and that there is a need for more in-depth research into the interactions between the rural context and the specific HIV risk knowledge and behaviours that affect HIV risk in this population.     

Elucidating the effect of precursor decomposition time on the structural and optical properties of copper(i) nitride nanocubes

To study the effect of time on the colloidal synthesis of Cu₃N nanoparticles, copper(ii) nitrate was thermally decomposed at 260 °C for up to 60 min in octadecylamine as a stabilizing ligand. Thermolysis of the nitrate followed four steps which included; nucleation, growth, ripening and decomposition. At 5 min, partially developed nanocubes were found in a dense population of Cu₃N nuclei. Well-defined Cu₃N nanocubes were obtained at 15 min with no presence of the nuclei. TEM images showed disintegration of the cubes at 20 min and as time progressed, all the Cu₃N decomposed to Cu by 60 min. The formation of the Cu₃N nanocubes was confirmed by XRD and XPS. FTIR suggested the formation of a nitrile (RCN) as a result of the thermal decomposition in octadecylamine (ODA) and this was confirmed using NMR and hence, a reaction mechanism was then proposed. The optical properties of the as-synthesized Cu₃N were studied using UV-vis and photoluminescence spectroscopies. The absorption spectra for particles synthesized from 5 min to 15 min showed a singular exciton peak while from 20 min to 60 min two peaks were observed. The two peaks may both be associated with the two direct transitions observed in Cu₃N or the more red-shifted peak could be a result of localized surface plasmon resonance due to the Cu nanoparticles. Nevertheless, similar to other studies, it is clear that the optical properties of Cu₃N are complex.

To study the effect of time on the colloidal synthesis of Cu₃N nanoparticles, copper(ii) nitrate was thermally decomposed at 260 °C for up to 60 min in octadecylamine as a stabilizing ligand.     

Southern Africa ports as spaces of HIV vulnerability: case studies from South Africa and Namibia

There is increasing recognition that in order to respond to the HIV epidemic migrants and mobile populations must be included in national and regional responses. While migration in and of itself does not necessarily contribute to increased risk of HIV infection, some migrants and mobile populations do face increased HIV risk. With its immense coastline and extensive transport industry, Southern Africa provides an excellent case study to examine the HIV risks and vulnerabilities of mobile workers and local communities through port settings. IOM's research in Southern African ports illustrates why HIV/AIDS policies and programmes must focus on spaces where migrants and mobile populations interact with sedentary populations (including sex workers and other sexual partners) in environments conducive to multiple concurrent partnerships, in order to reduce HIV risk and increase access to treatment, care, and support for all.     

Novel 2D-AuSe nanostructures as effective platinum replacement counter electrodes in dye-sensitized solar cells

Studies to improve the efficiency of dye-sensitized solar cells (DSSCs) include, but are not limited to, finding alternatives such as 2D layered materials as replacement counter electrodes (CEs) to the commonly used Pt. Herein, we report for the first time, the use of AuSe as a counter electrode for the reduction of triiodide ions (I₃⁻) to iodide ions (I⁻). The colloidal synthesis of gold selenide nanostructures produced α-AuSe and β-AuSe dominated products as determined by XRD. Electron microscopy showed α-AuSe having belt-like structures while β-AuSe had a plate-like morphology. EDS mapping confirmed the elemental composition and homogeneity of the AuSe CEs. Cyclic voltammetry curves of the AuSe CEs displayed the double set of reduction–oxidation peaks associated with the reactions in the I₃⁻/I⁻ electrolyte and therefore were comparable to the Pt CV curve. The α-AuSe CE showed better electrocatalytic activity with a reduction current of 6.1 mA than that of β-AuSe and Pt CEs, which were 4.2 mA and 4.8 mA, respectively. The peak-to-peak separation (ΔE_pp) for the α-AuSe CE was also more favourable with a value of 532 mV over that of the β-AuSe CE of 739 mV however, both values were larger than that of the Pt CE, which was found to be 468 mV. The EIS and Tafel plot data showed that α-AuSe had the best catalytic activity compared to β-AuSe and was comparable to Pt. The DSSC using α-AuSe as a CE had the highest PCE (6.94%) as compared to Pt (4.89%) and β-AuSe (3.47%). The lower efficiency for Pt was attributed to the poorer fill factor. With these novel results, α-AuSe is an excellent candidate to be used as an alternative CE to Pt in DSSCs.

Studies to improve the efficiency of dye-sensitized solar cells (DSSCs) include, but are not limited to, finding alternatives such as 2D layered materials as replacement counter electrodes (CEs) to the commonly used Pt.     

Amide Tethered 4-Aminoquinoline-naphthalimide Hybrids: A New Class of Possible Dual Function Antiplasmodials

A series of amide tethered 4-aminoquinoline-naphthalimide hybrids has been synthesized to assess their in vitro antiplasmodial potential against chloroquine-susceptible (3D7) and chloroquine-resistant (W2) strains of Plasmodium falciparum. The most active and noncytotoxic compound had an IC₅₀ value of 0.07 μM against W2 strain and was more active than standard antimalarial drugs, including chloroquine, desethylamodiaquine, and quinine, particularly for drug resistant malaria. The promising scaffold, when subjected to heme binding and molecular modeling studies, was identified as a possible potent inhibitor of hemozoin formation and P. falciparum chloroquine resistance transporter (PfCRT), respectively, and, therefore, could act as a dual function antiplasmodial.     

Diastereoselective approach to rationally design tetrahydro-β-carboline–isatin conjugates as potential SERMs against breast cancer

A series of tetrahydro-β-carboline–isatin conjugates, with varying substituents as well as stereochemistry at C-1 and C-5 position of tetrahydro-β-carboline (THβC) and isatin ring, were prepared and assayed for anti-proliferative efficacy on Estrogen Responsive ER(+) (MCF-7) and ER(−ve) MDA-MB-231 cell-lines. The synthesized scaffolds displayed selective anti-proliferative efficacy against MCF-7 cell-line with the most active conjugate 8b exhibiting an IC₅₀ value of 37.42 μM, comparable to that of peganumine A, a tetrahydro-β-carboline analogue, isolated from Peganum harmala. The synthesized compound 8b was also more potent than the standard drug tamoxifen (IC₅₀ = 50 μM against MCF-7). The observed activities were further corroborated via docking studies in ER-α (PDB ID: 3ERT).

A series of tetrahydro-β-carboline–isatin conjugates was prepared and assayed for anti-proliferative activities on Estrogen Responsive ER(+) and non-responsive ER(−ve) cell-lines.     

Gender factors associated with sexual abstinent behaviour of rural South African high school going youth in KwaZulu-Natal, South Africa

The cross-sectional study investigated South African rural high school learners' choice of sexual abstinence in order to be able to develop tailored health education messages. All Grade 9 learners from one class at each of 10 randomly selected rural high schools participated. The Integrated Model for Motivational and Behavioural Change was used to elicit attitudes, social influences, self-efficacy and intentions towards sexual abstinence. Chi-square and t-tests were used for bivariate analysis. In total, 454 learners, mean age 16.7 years (standard deviation 1.41) range 14-20 years, participated, of whom 246 (54.2%) were female. When comparing learners reporting abstinence (n=252) with those not abstinent (n=202), abstinent learners were significantly more often females (P<0.005), younger (16.5 years versus 17.1 years, P<0.005) and drank less alcohol (P<0.005). Abstaining girls believed that their friends and parents think that they should abstain from sex, that their friends abstained from sex and that abstinence helped them to mature emotionally. Abstinent boys expressed intentions to abstain from sex until marriage. Targeted intervention research is required to encourage South African rural high school learners to delay their sexual initiation to reduce their risk of human immunodeficiency virus infection. Different abstinent messages are needed for boys and girls to address the different patterns of behaviour observed.     

Probing the stoichiometry dependent catalytic activity of nickel selenide counter electrodes in the redox reaction of iodide/triiodide electrolyte in dye sensitized solar cells

Nickel selenide (Ni_xSe_y) systems have received much attention in recent years as potential low cost counter electrodes (CEs) in dye sensitized solar cells (DSSCs). Their electrocatalytic activities are comparable to that of the conventional platinum CE. Despite their achievements, the effect of stoichiometry on their catalytic performance as CEs in DSSCs still remains unclear, hence the motivation for this work. Different stoichiometries of Ni_xSe_y were synthesized via a colloidal method in oleylamine or oleylamine/oleic acid mixture at the appropriate synthetic temperature and Ni to Se precursor ratio. X-ray diffraction revealed that different stoichiometries of nickel selenide were formed namely, NiSe₂, Ni₃Se₄, Ni_0.85Se, NiSe and Ni₃Se₂. Scanning electron microscopy showed that all the stoichiometries had predominantly spherical-like morphologies. Cyclic voltammetry, electrochemical impedance spectroscopy analysis and the photovoltaic performances of the DSSCs fabricated using the different Ni_xSe_y CEs revealed that selenium rich stoichiometries performed better than the nickel rich ones. Consequently, the catalytic activity towards the redox reaction of the triiodide/iodide electrolyte and hence the power conversion efficiency (PCE) followed the order of NiSe₂ > Ni₃Se₄ > Ni_0.85Se > NiSe > Ni₃Se₂ with PCE values of 3.31%, 3.25%, 3.17%, 2.35% and 1.52% respectively under ambient conditions.

Nickel selenide (Ni_xSe_y) systems have received much attention in recent years as potential low cost counter electrodes (CEs) in dye sensitized solar cells (DSSCs).