THE DESIGN AND SYNTHESIS OF NEW ORGANIC DITHIOLS FOR ENVIRONMENTAL APPLICATIONS

A thiol molecule, 2,6-pyridinediamidoethanethiol (PB9), was synthesized based on the pyridine-2,6-dicarboxamide scaffold with appended cysteamine groups. PB9 acts as an effective chelator for Pb(II) due to multiple binding sites (N3S2) through irreversible binding precipitating Pb(II). Removal of aqueous Pb(II) from solution was demonstrated by exploring the effects of time, initial PB9:Pb(II) ratios, pH, exposure time, and solution temperature. After 15 min the Pb(II) concentrations were reduced from 50.00 ppm to 0.30 ppm (99.4%) and 0.25 ppm (99.5%) for PB9:Pb ratios of 1:1 and 2:1, respectively. Removal of \u3e 93% Pb(II) was observed over multiple pH values with negligible susceptibility for leaching over time. The thermodynamic studies reveal that the removal of Pb(II) from solution is an entropically driven, spontaneous process. Solution-state (UV−vis, 1H-NMR, 13C- NMR) along with solid-state (IR, Raman, and thermal) studies of PB9/Pb(II) compounds were performed. UV-vis displays a global maximum at 274 nm and a local maximum at 327 nm for ligand-to-metal charge transfer S- 3p to Pb2+ 6p, and intraatomic Pb2+ 6s to Pb2+ 6p transitions. FT-IR absorption spectra show significant absorption bands corresponding to amide I (C=O stretching) and amide II bands (C-N stretching, NH bending). The spectral shifting due to coordination of the amidic and pyridinic N to Pb(II) and further covalent bonding with sulfur was observed. Probable PB9 + Pb(II) interactions are proposed based on the techniques above mentioned. The molecular structure was designed as PB9 behaving like a bis-deprotonated ligand with an N3S2 donor set to give Pb(II) a trigonal bipyramidal environment with non-stereochemically active s electrons. The existence of a cyclic oligomeric (PB9)4(Pb)4 or polymeric (PB9)ꝏ(Pb)ꝏ structure is evidenced by broad melting point, insolubility in most common solvents, and amorphous powder XRD. Moreover, PB9 also exhibits high sensitivity and selectivity towards Fe(III) over other metal ions by fluorescent quenching. Theoretical studies comprising Benesi- Hildebrand, and studies such as Job’s plot, Stern-Volmer (S-V), and detection limits illustrate higher sensing abilities, possible dynamic and static quenching, and reversibility of binding. The quenching efficiency found by S-V is 7.42 ± 0.03 × 103 M−1. Job’s plot indicates the molar binding ratio of PB9: Fe(III) as 1:1 with a higher apparent association constant of 9.537 × 103 M–1 from the Benesi- Hildebrand plot. A linear range of Fe(III) (0 – 80 µM) with a detection limit of 0.59 µM (0.003 ppm) was found. The obtained detection limit was much lower than the maximum allowable limit of Fe(III) (0.3 ppm) regulated by EPA in drinking water. PB9-sensor exhibits visible color change from colorless to yellow acting like a naked-eye detector for Fe(III). In a separate study, 2,2\u27-(isophthalolybis(azanediyl))bis-3-mercaptopropanoic acid (AB9) was coupled to amine-functionalized silica and silica-coated magnetic nanoparticles (with magnetite, Fe3O4, core). This exploration was conducted for achieving \u3e 15 ppb (EPA level in drinking water) by a previously established method in the lab. The impact of initial concentration, pH, exposure time, and adsorbent dosage on the adsorption properties of Pb(II) from an aqueous solution was studied and optimized. Characterization was performed with ICP, FT-IR, Raman, XRD, TEM, and SEM. Results revealed successful fabrication of AB9 on mesoporous silica and MNP surfaces without introducing crystalline impurities. Indeed, an added advantage for AB9-MNP over AB9-silica is its magnetic nature, whereby a magnet was used to isolate the Pb(II)-containing (solid) composite from the treated water. The \u3e 99.9% removal of Pb(II) was obtained by AB9-MNP with detectable Pb(II) dropping below 15 ppb EPA level. The obtained equilibrium results were inserted in various adsorption isotherm models, including Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich. The data was in agreement with the Langmuir model, suggesting a dominant chemical adsorption mechanism on mesoporous AB9- silica and AB9-MNP with monolayer coverage. Maximum adsorption capacities were 22.05, 24.80, 35.57, and 56.40 mg/g, respectively, for silica, AB9-silica, MNP, and AB9-MNP. This demonstrates that a thiol group improves the adsorption capacity of Pb(II). This is an eco-friendly modification with rapid magnetic separation and chemicals utilizing HSAB to form stable compounds. Lack of complicated operations, extensive reaction times, high temperatures or high pressures, and toxic/ harmful reaction media make these AB9-MNP a good candidate for aqueous Pb(II) removal

Transitioning from donor aid for health: perspectives of national stakeholders in Ghana

Background Ghana’s shift from low-income to middle-income status will make it ineligible to receive concessional aid in the future. While transition may be a reflection of positive changes in a country, such as economic development or health progress, a loss of support from donor agencies could have negative impacts on health system performance and population health. We aimed to identify key challenges and opportunities that Ghana will face in dealing with aid transition, specifically from the point of view of country-level stakeholders.Methods We conducted key informant interviews with 18 stakeholders from the government, civil society organisations and donor agencies in Ghana using a semistructured interview guide. We performed directed content analysis of the interview transcripts to identify key themes related to anticipated challenges and opportunities that might result from donor transitions.Results Overall, stakeholders identified challenges more frequently than opportunities. All stakeholders interviewed believe that Ghana will face substantial challenges due to donor transitions. Challenges include difficulty filling financial gaps left by donors, the shifting of national priorities away from the health sector, lack of human resources for health, interrupted care for beneficiaries of donor-funded health programmes, neglect of vulnerable populations and loss of the accountability mechanisms that are linked with donor financing. However, stakeholders also identified key opportunities that transitions might present, including efficiency gains, increased self-determination and self-sufficiency, enhanced capacity to leverage domestic resources and improved revenue mobilisation.Conclusion Stakeholders in Ghana believe transitioning away from aid for health presents both challenges and opportunities. The challenges could be addressed by conducting a transition readiness assessment, identifying health sector priorities, developing a transition plan with a budget to continue critical health programmes and mobilising greater political commitment to health. The loss of aid could be turned into an opportunity to integrate vertical programmes into a more comprehensive health system

Adaptation of a Theory-Based Social Networking and Gamified App-Based Intervention to Improve Pre-Exposure Prophylaxis Adherence Among Young Men Who Have Sex With Men in Bangkok, Thailand: Qualitative Study

BackgroundHIV disproportionately affects young Thai men who have sex with men (YMSM). Recent studies report a high incidence and prevalence of HIV among Thai YMSM. The Thai national guidelines have recommended pre-exposure prophylaxis (PrEP) since 2014 for key populations; free PrEP has been piloted since 2019. Smartphone-based mobile health (mHealth) interventions provide an optimal platform for innovative PrEP adherence interventions for Thai YMSM. ObjectiveThis study aims to adapt the P3 (Prepared, Protected, emPowered) app, developed with YMSM and transwomen in the United States to improve PrEP adherence and persistence for YMSM in Thailand. The app aims to provide daily adherence support and addresses gaps in staff available for large-scale PrEP rollout needed to see population-level effects of HIV prevention. MethodsWe conducted focus group discussions (FGDs) with YMSM and key informant interviews (KIIs) with PrEP care providers in Bangkok, Thailand, to investigate PrEP adherence facilitators and barriers, preferences for functions and features in mHealth apps among YMSM, and how to best adapt the P3 app to the Thai context. We conducted four FGDs with 4-8 participants per group and 15 KIIs. ResultsFor FGDs, 23 YMSM participated with a mean age of 20 years (range 18-21), 96% (22/23) enrolled in full-time education, and all owned smartphones. The mean age of KII participants was 40 (range 26-60) years; most were state health service providers, with the majority being counselors (6/15, 40%) and physicians (6/15, 40%). Overall, the facilitators and barriers for PrEP adherence identified were similar to those of MSM and YMSM globally including the United States. Key themes included general recommendations for improving mHealth apps in Thailand, such as presenting reliable information in an appealing format, minimizing privacy risks, and addressing connectivity challenges. Additional themes focused on P3 Thailand adaptations and were related to cultural and stylistic preferences, engagement strategies, and recommendations for new functions. To develop the adapted app, P3 Thailand, these findings were balanced with resource limitations resulting in the prioritization of minor modifications: changes in app esthetics (color scheme, iconography, and imagery) and changes in the presentation of information in two of the app’s features. FGDs identified similar PrEP adherence facilitators and barriers to those already addressed within the app. ConclusionsThe core elements of the P3 app address major PrEP facilitators and barriers for Thai YMSM; however, changes to the app features, including stylistic presentation, were needed to appropriately customize the app to the Thai context. Given the similarities of facilitators and barriers for PrEP adherence globally, adapting existing PrEP mHealth solutions based on input from end users and key informants provides a promising approach. However, partnerships with local app designers and developers can improve the adaptation process and final product. Trial RegistrationClinicalTrials.gov NCT04413708; http://clinicaltrials.gov/ct2/show/NCT0441370