Design and Optimization of High-Performance Novel RbPbBr3-Based Solar Cells with Wide-Band-Gap S-Chalcogenide Electron Transport Layers (ETLs).

Inorganic cubic rubidium-lead-halide perovskites have attracted considerable attention owing to their structural, electronic, and unique optical properties. In this study, novel rubidium-lead-bromide (RbPbBr3)-based hybrid perovskite solar cells (HPSCs) with several high-band-gap chalcogenide electron transport layers (ETLs) of In2S3, WS2, and SnS2 were studied by density functional theory (DFT) and using the SCAPS-1D simulator. Initially, the band gap and optical performance were computed using DFT, and these results were utilized for the first time in the SCAPS-1D simulator. Furthermore, the impact of different major influencing parameters, that is, the thickness of the layer, bulk defect density, doping concentration, and defect density of interfaces, including the working temperature, were also investigated and unveiled. Further, a study on an optimized device with the most potential ETL (SnS2) layer was performed systematically. Finally, a comparative study of different reported heterostructures was performed to explore the benchmark of the most recent efficient RbPbBr3-based photovoltaics. The highest power conversion efficiency (PCE) was 29.75% for the SnS2 ETL with Voc of 0.9789 V, Jsc of 34.57863 mA cm-2, and fill factor (FF) of 87.91%, while the PCEs of 21.15 and 24.57% were obtained for In2S3 and WS2 ETLs, respectively. The electron-hole generation, recombination rates, and quantum efficiency (QE) characteristics were also investigated in detail. Thus, the SnS2 ETL shows strong potential for use in RbPbBr3-based hybrid perovskite high-performance photovoltaic devices.

Boosting efficiency above 28% using effective charge transport layer with Sr3SbI3 based novel inorganic perovskite.

Strontium antimony iodide (Sr3SbI3) is one of the emerging absorbers materials owing to its intriguing structural, electronic, and optical properties for efficient and cost-effective solar cell applications. A comprehensive investigation on the structural, optical, and electronic characterization of Sr3SbI3 and its subsequent applications in heterostructure solar cells have been studied theoretically. Initially, the optoelectronic parameters of the novel Sr3SbI3 absorber, and the possible electron transport layer (ETL) of tin sulfide (SnS2), zinc sulfide (ZnS), and indium sulfide (In2S3) including various interface layers were obtained by DFT study. Afterward, the photovoltaic (PV) performance of Sr3SbI3 absorber-based cell structures with SnS2, ZnS, and In2S3 as ETLs were systematically investigated at varying layer thickness, defect density bulk, doping density, interface density of active materials including working temperature, and thereby, optimized PV parameters were achieved using SCAPS-1D simulator. Additionally, the quantum efficiency (QE), current density-voltage (J-V), and generation and recombination rates of photocarriers were determined. The maximum power conversion efficiency (PCE) of 28.05% with JSC of 34.67 mA cm-2, FF of 87.31%, VOC of 0.93 V for SnS2 ETL was obtained with Al/FTO/SnS2/Sr3SbI3/Ni structure, while the PCE of 24.33%, and 18.40% in ZnS and In2S3 ETLs heterostructures, respectively. The findings of this study contribute to in-depth understanding of the physical, electronic, and optical properties of Sr3SbI3 absorber perovskite and SnS2, ZnS, and In2S3 ETLs. Additionally, it provides valuable insights into the potential of Sr3SbI3 in heterostructure perovskite solar cells (PSCs), paving the pathway for further experimental design of an efficient and stable PSC devices.

High efficiency Cu2MnSnS4 thin film solar cells with SnS BSF and CdS ETL layers: A numerical simulation.

The quaternary compound copper manganese tin sulfide Cu2MnSnS4 is a potential absorber semiconductor material for fabricating thin film solar cells (TFSC) thanks to their promising optoelectronic parameters. This article numerically investigated the performance of Cu2MnSnS4 (CMTS)-based TFSC without and with tin sulphide (SnS) back surface field (BSF) thin-film layer. First, the impact of several major influential parameters such as the active material's thickness, doping concentration of photoactive materials, density of bulk and interface defect, working temperature, and metal contact, were studied systematically without a BSF layer. Thereafter, the photovoltaic performance of the optimized pristine cell was further investigated with an SnS as BSF inserted between the absorber (CMTS) with a Platinum back metal of an optimized heterostructure of Cu/ZnO:Al/i-ZnO/n-CdS/p-Cu2MnSnS4/Pt. Thus, the photoconversion efficiency (PCE) of 25.43% with a J SC of 34.41nullmA/cm2 and V OC of 0.883 V was achieved under AM1.5G solar spectrum without SnS BSF layer. Furthermore, an improved PCE of 31.4% with a J SC of 36.21nullmA/cm2 and V OC of 1.07 V was achieved with a quantum efficiency of over 85% in the wavelengths of 450-1000 nm by the addition of SnS BSF layer. Thus, this obtained systematic and consistent outcomes reveal immense potential of CMTS with SnS as absorber and BSF, respectively and provide imperious guidance for fabricating highly a massive potential efficient solar cell.

Stakeholder perceptions on scaling-up community-led interventions for prevention and control of non-communicable diseases in Bangladesh: a qualitative study.

BACKGROUND: Engaging communities is an important component of multisectoral action to address the growing burden of non-communicable diseases (NCDs) in low- and middle-income countries. We conducted research with non-communicable disease stakeholders in Bangladesh to understand how a community-led intervention which was shown to reduce the incidence of type 2 diabetes in rural Bangladesh could be scaled-up. METHODS: We purposively sampled any actor who could have an interest in the intervention, or that could affect or be affected by the intervention. We interviewed central level stakeholders from donor agencies, national health policy levels, public, non-governmental, and research sectors to identify scale-up mechanisms. We interviewed community health workers, policy makers, and non-governmental stakeholders, to explore the feasibility and acceptability of implementing the suggested mechanisms. We discussed scale-up options in focus groups with community members who had attended a community-led intervention. We iteratively developed our data collection tools based on our analysis and re-interviewed some participants. We analysed the data deductively using a stakeholder analysis framework, and inductively from codes identified in the data. RESULTS: Despite interest in addressing NCDs, there was a lack of a clear community engagement strategy at the government level, and most interventions have been implemented by non-governmental organisations. Many felt the Ministry of Health and Family Welfare should lead on community engagement, and NCD screening and referral has been added to the responsibilities of community health workers and health volunteers. Yet there remains a focus on reproductive health and NCD diagnosis and referral instead of prevention at the community level. There is potential to engage health volunteers in community-led interventions, but their present focus on engaging women for reproductive health does not fit with community needs for NCD prevention. CONCLUSIONS: Research highlighted the need for a preventative community engagement strategy to address NCDs, and the potential to utilise existing cadres to scale-up community-led interventions. It will be important to work with key stakeholders to address gender issues and ensure flexibility and responsiveness to community concerns. We indicate areas for further implementation research to develop scaled-up models of community-led interventions to address NCDs.

Intermediate hyperglycaemia, diabetes and blood pressure in rural Bangladesh: five-year post-randomisation follow-up of the DMagic cluster-randomised controlled trial.

Background: The DMagic trial showed that participatory learning and action (PLA) community mobilisation delivered through facilitated community groups, and mHealth voice messaging interventions improved diabetes knowledge in Bangladesh and the PLA intervention reduced diabetes occurrence. We assess intervention effects three years after intervention activities stopped. Methods: Five years post-randomisation, we conducted a cross-sectional survey among a random sample of adults aged ≥30-years living in the 96 DMagic villages, and a cohort of individuals identified with intermediate hyperglycaemia at the start of the DMagic trial in 2016. Primary outcomes were: 1) the combined prevalence of intermediate hyperglycaemia and diabetes; 2) five-year cumulative incidence of diabetes among the 2016 cohort of individuals with intermediate hyperglycaemia. Secondary outcomes were: weight, BMI, waist and hip circumferences, blood pressure, knowledge and behaviours. Primary analysis compared outcomes at the cluster level between intervention arms relative to control. Findings: Data were gathered from 1623 (82%) of the randomly selected adults and 1817 (87%) of the intermediate hyperglycaemia cohort. 2018 improvements in diabetes knowledge in mHealth clusters were no longer observable in 2021. Knowledge remains significantly higher in PLA clusters relative to control but no difference in primary outcomes of intermediate hyperglycaemia and diabetes prevalence (OR (95%CI) 1.23 (0.89, 1.70)) or five-year incidence of diabetes were observed (1.04 (0.78, 1.40)). Hypertension (0.73 (0.54, 0.97)) and hypertension control (2.77 (1.34, 5.75)) were improved in PLA clusters relative to control. Interpretation: PLA intervention effect on intermediate hyperglycaemia and diabetes was not sustained at 3 years after intervention end, but benefits in terms of blood pressure reduction were observed. Funding: Medical Research Council UK: MR/M016501/1 (DMagic trial); MR/T023562/1 (DClare study), under the Global Alliance for Chronic Diseases (GACD) Diabetes and Scale-up Programmes, respectively.

Community participatory learning and action cycle groups to reduce type 2 diabetes in Bangladesh (D:Clare): an updated study protocol for a parallel arm cluster randomised controlled trial.

The "Diabetes: Community-led Awareness, Response and Evaluation" (D:Clare) trial aims to scale up and replicate an evidence-based participatory learning and action cycle intervention in Bangladesh, to inform policy on population-level T2DM prevention and control.The trial was originally designed as a stepped-wedge cluster randomised controlled trial, with the interventions running from March 2020 to September 2022. Twelve clusters were randomly allocated (1:1) to implement the intervention at months 1 or 12 in two steps, and evaluated through three cross-sectional surveys at months 1, 12 and 24. However, due to the COVID-19 pandemic, we suspended project activities on the 20th of March 2020. As a result of the changed risk landscape and the delays introduced by the COVID-19 pandemic, we changed from the stepped-wedge design to a wait-list parallel arm cluster RCT (cRCT) with baseline data. We had four key reasons for eventually agreeing to change designs: equipoise, temporal bias in exposure and outcomes, loss of power and time and funding considerations.Trial registration ISRCTN42219712 . Registered on 31 October 2019.

An extensive study on multiple ETL and HTL layers to design and simulation of high-performance lead-free CsSnCl3-based perovskite solar cells.

Cesium tin chloride (CsSnCl3) is a potential and competitive absorber material for lead-free perovskite solar cells (PSCs). The full potential of CsSnCl3 not yet been realized owing to the possible challenges of defect-free device fabrication, non-optimized alignment of the electron transport layer (ETL), hole transport layer (HTL), and the favorable device configuration. In this work, we proposed several CsSnCl3-based solar cell (SC) configurations using one dimensional solar cell capacitance simulator (SCAPS-1D) with different competent ETLs like indium-gallium-zinc-oxide (IGZO), tin-dioxide (SnO2), tungsten disulfide (WS2), ceric dioxide (CeO2), titanium dioxide (TiO2), zinc oxide (ZnO), C60, PCBM, and HTLs of cuprous oxide (Cu2O), cupric oxide (CuO), nickel oxide (NiO), vanadium oxide (V2O5), copper iodide (CuI), CuSCN, CuSbS2, Spiro MeOTAD, CBTS, CFTS, P3HT, PEDOT:PSS. Simulation results revealed that ZnO, TiO2, IGZO, WS2, PCBM, and C60 ETLs-based halide perovskites with ITO/ETLs/CsSnCl3/CBTS/Au heterostructure exhibited outstanding photoconversion efficiency retaining nearest photovoltaic parameters values among 96 different configurations. Further, for the six best-performing configurations, the effect of the CsSnCl3 absorber and ETL thickness, series and shunt resistance, working temperature, impact of capacitance, Mott-Schottky, generation and recombination rate, current-voltage properties, and quantum efficiency on performance were assessed. We found that ETLs like TiO2, ZnO, and IGZO, with CBTS HTL can act as outstanding materials for the fabrication of CsSnCl3-based high efficiency (η ≥ 22%) heterojunction SCs with ITO/ETL/CsSnCl3/CBTS/Au structure. The simulation results obtained by the SCAPS-1D for the best six CsSnCl3-perovskites SC configurations were compared by the wxAMPS (widget provided analysis of microelectronic and photonic structures) tool for further validation. Furthermore, the structural, optical and electronic properties along with electron charge density, and Fermi surface of the CsSnCl3 perovskite absorber layer were computed and analyzed using first-principle calculations based on density functional theory. Thus, this in-depth simulation paves a constructive research avenue to fabricate cost-effective, high-efficiency, and lead-free CsSnCl3 perovskite-based high-performance SCs for a lead-free green and pollution-free environment.

Concurrent investigation of antimony chalcogenide (Sb2Se3 and Sb2S3)-based solar cells with a potential WS2 electron transport layer.

Antimony (Sb) chalcogenides such as antimony selenide (Sb2Se3) and antimony sulfide (Sb2S3) have distinct properties to be used as absorber semiconductors for harnessing solar energy including high absorption coefficient, tunable bandgap, low toxicity, phase stability. The potentiality of Sb2Se3 and Sb2S3 as absorber material in Al/FTO/Sb2Se3(or Sb2S3)/Au heterojunction solar cells (HJSCs) with 2D tungsten disulfide (WS2) electron transport layer (ETL) layer has been investigated numerically using SCAPS-1D solar simulator. A systematic investigation of the impact of physical properties of each active material of Sb2Se3, Sb2S3, and WS2 on photovoltaic parameters including layer thickness, carrier doping concentration, bulk defect density, interface defect density, carrier generation, and recombination. This study emphasizes the exploration of causes of low performance of actual devices and demonstrates the individual variation in the open-circuit voltage (VOC), short-circuit current density (JSC), fill factor (FF), power conversion efficiency (PCE) and quantum efficiency (QE). Thereby, highly potential heterostructures of Al/FTO/WS2/absorber (Sb2Se3 or Sb2S3)/Au proposed, in which, the PCE over 28.20 and 26.60% obtained with V OC of 850 and 1230 mV, J sc of 38.0 and 24.0 mA/cm2, and FF of 86.0 and 89.0% for Sb2Se3 and Sb2S3 absorber, respectively. These detailed findings revealed that the Sb-chalcogenide heterostructure with potential WS2 ETL can be used to realize the fabrication of feasible thin film solar cells and thus the design of high-efficiency high-current (HEHC) and high-efficiency high-voltage (HEHV) solar panels.

Equity impact of participatory learning and action community mobilisation and mHealth interventions to prevent and control type 2 diabetes and intermediate hyperglycaemia in rural Bangladesh: analysis of a cluster randomised controlled trial.

BACKGROUND: A cluster randomised trial of mHealth and participatory learning and action (PLA) community mobilisation interventions showed that PLA significantly reduced the prevalence of intermediate hyperglycaemia and type 2 diabetes mellitus (T2DM) and the incidence of T2DM among adults in rural Bangladesh; mHealth improved knowledge but showed no effect on glycaemic outcomes. We explore the equity of intervention reach and impact. METHODS: Intervention reach and primary outcomes of intermediate hyperglycaemia and T2DM were assessed through interview surveys and blood fasting glucose and 2-hour oral glucose tolerance tests among population-based samples of adults aged ≥30 years. Age-stratified, gender-stratified and wealth-stratified intervention effects were estimated using random effects logistic regression. RESULTS: PLA participants were similar to non-participants, though female participants were younger and more likely to be married than female non-participants. Differences including age, education, wealth and marital status were observed between individuals exposed and those not exposed to the mHealth intervention.PLA reduced the prevalence of T2DM and intermediate hyperglycaemia in all age, gender and wealth strata. Reductions in 2-year incidence of T2DM of at least 51% (0.49, 95% CI 0.26 to 0.92) were observed in all strata except among the oldest and least poor groups. mHealth impact on glycaemic outcomes was observed only among the youngest group, where a 47% reduction in the 2-year incidence of T2DM was observed (0.53, 95% CI 0.28 to 1.00). CONCLUSION: Large impacts of PLA across all strata indicate a highly effective and equitable intervention. mHealth may be more suitable for targeting higher risk, younger populations. TRIAL REGISTRATION NUMBER: ISRCTN41083256.

Learning from a diabetes mHealth intervention in rural Bangladesh: what worked, what did not and what next?

There is an urgent need for population-based interventions to slow the growth of the diabetes epidemic in low-and middle-income countries. We tested the effectiveness of a population-based mHealth voice messaging intervention for T2DM prevention and control in rural Bangladesh through a cluster randomised controlled trial. mHealth improved knowledge and awareness about T2DM but there was no detectable effect on T2DM occurrence. We conducted mixed-methods research to understand this result. Exposure to messages was limited by technological faults, high frequency of mobile phone number changes, message fatigue and (mis)perceptions that messages were only for those who had T2DM. Persistent social norms, habits and desires made behaviour change challenging, and participants felt they would be more motivated by group discussions than mHealth messaging alone. Engagement with mHealth messages for T2DM prevention and control can be increased by (1) sending identifiable messages from a trusted source (2) using participatory design of mHealth messages to inform modelling of behaviours and increase relevance to the general population (3) enabling interactive messaging. mHealth messaging is likely to be most successful if implemented as part of a multi-sectoral, multi-component approach to address T2DM and non-communicable disease risk factors.

Changes in non-communicable diseases, diet and exercise in a rural Bangladesh setting before and after the first wave of COVID-19.

Prevalence of non-communicable diseases (NCDs) is high in rural Bangladesh. Given the complex multi-directional relationships between NCDs, COVID-19 infections and control measures, exploring pandemic impacts in this context is important. We conducted two cross-sectional surveys of adults ≥30-years in rural Faridpur district, Bangladesh, in February to March 2020 (survey 1, pre-COVID-19), and January to March 2021 (survey 2, post-lockdown). A new random sample of participants was taken at each survey. Anthropometric measures included: blood pressure, weight, height, hip and waist circumference and fasting and 2-hour post-glucose load blood glucose. An interviewer-administered questionnaire included: socio-demographics; lifestyle and behavioural risk factors; care seeking; self-rated health, depression and anxiety assessments. Differences in NCDs, diet and exercise were compared between surveys using chi2 tests, logistic and linear regression; sub-group analyses by gender, age and socio-economic tertiles were conducted. We recruited 950 (72.0%) participants in survey 1 and 1392 (87.9%) in survey 2. The percentage of the population with hypertension increased significantly from 34.5% (95% CI: 30.7, 38.5) to 41.5% (95% CI: 38.2, 45.0; p-value = 0.011); the increase was more pronounced in men. Across all measures of self-reported health and mental health, there was a significant improvement between survey 1 and 2. For self-rated health, we observed a 10-point increase (71.3 vs 81.2, p-value = 0.005). Depression reduced from 15.3% (95% CI: 8.4, 26.1) to 6.0% (95% CI: 2.7, 12.6; p-value = 0.044) and generalised anxiety from 17.9% (95% CI: 11.3, 27.3) to 4.0% (95% CI: 2.0, 7.6; p-value<0.001). No changes in fasting blood glucose, diabetes status, BMI or abdominal obesity were observed. Our findings suggest both positive and negative health outcomes following COVID-19 lockdown in a rural Bangladeshi setting, with a concerning increase in hypertension. These findings need to be further contextualised, with prospective assessments of indirect effects on physical and mental health and care-seeking.

Mist chemical vapor deposition of crystalline MoS2atomic layer films using sequential mist supply mode and its application in field-effect transistors.

Molybdenum disulfide (MoS2) mono/bilayer have been systematically investigated using atmospheric-pressure mist chemical vapor deposition (mist CVD) from (NH4)2MoS4dissolved in N-methyl-2-pyrrolidone as a precursor. Film deposition was performed by alternating MoS2mist storage within a closed chamber and mist exhaust, i.e. sequential mist supply mode at different furnace temperatures, storage times of precursor, and repetition cycles of mist supply on thermally grown SiO2(th-SiO2) and mist-CVD grown Al1-xTixOy(ATO) layers coated on p+-Si substrates. The average size of the MoS2flake and their number of stack layers could be controlled by tuning the deposition parameters combined with substrate pretreatment. Field-effect transistors with MoS2atomic mono/bilayer as a channel layer exhibited mobility up to 31-40 (43-55) cm2V-1s-1with a threshold voltage of -1.6 (-0.5) V, subthreshold slope of 0.8 (0.11) V dec.-1, and on/off ratio of 3.2 × 104(3.6 × 105) onth-SiO2(ATO) layers as gate dielectric layers without mechanical exfoliation. These findings imply that mist CVD is available for the synthesis of metal transition metal dichalcogenide and metal oxide layers as channel and gate dielectric layers, respectively.

Care-seeking and managing diabetes in rural Bangladesh: a mixed methods study.

BACKGROUND: Type 2 diabetes mellitus poses a major health challenge worldwide and in low-income countries such as Bangladesh, however little is known about the care-seeking of people with diabetes. We sought to understand the factors that affect care-seeking and diabetes management in rural Bangladesh in order to make recommendations as to how care could be better delivered. METHODS: Survey data from a community-based random sample of 12,047 adults aged 30 years and above identified 292 individuals with a self-reported prior diagnosis of diabetes. Data on health seeking practices regarding testing, medical advice, medication and use of non-allopathic medicine were gathered from these 292 individuals. Qualitative semi-structured interviews and focus group discussions with people with diabetes and semi-structured interviews with health workers explored care-seeking behaviour, management of diabetes and perceptions on quality of care. We explore quality of care using the WHO model with the following domains: safe, effective, patient-centred, timely, equitable and efficient. RESULTS: People with diabetes who are aware of their diabetic status do seek care but access, particularly to specialist diabetes services, is hindered by costs, time, crowded conditions and distance. Locally available services, while more accessible, lack infrastructure and expertise. Women are less likely to be diagnosed with diabetes and attend specialist services. Furthermore costs of care and dissatisfaction with health care providers affect medication adherence. CONCLUSION: People with diabetes often make a trade-off between seeking locally available accessible care and specialised care which is more difficult to access. It is vital that health services respond to the needs of patients by building the capacity of local health providers and consider practical ways of supporting diabetes care. TRIAL REGISTRATION: ISRCTN41083256 . Registered on 30/03/2016.

Community participatory learning and action cycle groups to reduce type 2 diabetes in Bangladesh (D:Clare trial): study protocol for a stepped-wedge cluster randomised controlled trial.

BACKGROUND: An estimated 463 million people globally have diabetes, with the prevalence growing in low-and middle-income settings, such as Bangladesh. Given the need for context-appropriate interventions to prevent type 2 diabetes mellitus (T2DM), the 'Diabetes: Community-led Awareness, Response and Evaluation' (D:Clare) trial will rigorously evaluate the replication and scale-up of a participatory learning and action (PLA) cycle intervention in Bangladesh, to inform policy on population-level T2DM prevention and control. METHODS: This is a stepped-wedge cluster randomised controlled trial, with integrated process and economic evaluations, conducted from March 2020 to September 2022. The trial will evaluate a community-based four-phase PLA cycle intervention focused on prevention and control of T2DM implemented over 18 months, against a control of usual care. Twelve clusters will be randomly allocated (1:1) to implement the intervention at project month 1 or 12. The intervention will be evaluated through three cross-sectional surveys at months 1, 12 and 24. The trial will be conducted in Alfadanga Upazila, Faridpur district, with an estimated population of 120,000. Clusters are defined as administrative geographical areas, with approximately equal populations. Each of the six unions in Alfadanga will be divided into two clusters, forming 12 clusters in total. Given the risk of inter-cluster contamination, evaluation surveys will exclude villages in border areas. Participants will be randomly sampled, independently for each survey, from a population census conducted in January 2020. The primary outcome is the combined prevalence of intermediate hyperglycaemia and T2DM, measured through fasting and 2-h post-glucose load blood tests. A total of 4680 participants provide 84% power to detect a 30% reduction in the primary outcome, assuming a baseline of 30% and an ICC of 0.07. The analysis will be by intention-to-treat, comparing intervention and control periods across all clusters, adjusting for geographical clustering. DISCUSSION: This study will provide further evidence of effectiveness for community-based PLA to prevent T2DM at scale in a rural Bangladesh setting. However, we encountered several challenges in applying the stepped-wedge design to our research context, with particular consideration given to balancing seasonality, timing and number of steps and estimation of partial versus full effect. TRIAL REGISTRATION: ISRCTN: ISRCTN42219712 . Registered on 31 October 2019.

Participatory learning and action to address type 2 diabetes in rural Bangladesh: a qualitative process evaluation.

BACKGROUND: Diabetes is 7th largest cause of death worldwide, and prevalence is increasing rapidly in low-and middle-income countries. There is an urgent need to develop and test interventions to prevent and control diabetes and develop the theory about how such interventions can be effective. We conducted a participatory learning and action (PLA) intervention with community groups in rural Bangladesh which was evaluated through a cluster randomised controlled trial. There was a large reduction in the combined prevalence of type 2 diabetes and intermediate hyperglycaemia in the PLA group compared with the control group. We present findings from qualitative process evaluation research to explore how this intervention was effective. METHODS: We conducted group interviews and focus group discussions using photovoice with purposively sampled group attenders and non-attenders, and intervention implementers. Data were collected before the trial analysis. We used inductive content analysis to generate theory from the data. RESULTS: The intervention increased the health literacy of individuals and communities - developing their knowledge, capacity and self-confidence to enact healthy behaviours. Community, household and individual capacity increased through social support and social networks, which then created an enabling community context, further strengthening agency and enabling community action. This increased opportunities for healthy behaviour. Community actions addressed lack of awareness about diabetes, gendered barriers to physical activity and lack of access to blood glucose testing. The interaction between the individual, household, and community contexts amplified change, and yet there was limited engagement with macro level, or 'state', barriers to healthy behaviour. CONCLUSIONS: The participatory approach enabled groups to analyse how context affected their ability to have healthy behaviours and participants engaged with issues as a community in the ways that they felt comfortable. We suggest measuring health literacy and social networks in future interventions and recommend specific capacity strengthening to develop public accountability mechanisms and health systems strengthening to complement community-based interventions. TRIAL REGISTRATION: Registered at ISRCTN on 30th March 2016 (Retrospectively Registered) Registration number: ISRCTN41083256 .

Gendered perceptions of physical activity and diabetes in rural Bangladesh: a qualitative study to inform mHealth and community mobilization interventions.

Background Diabetes prevalence is increasing rapidly in Bangladesh, and there is an urgent need to promote preventive behaviours for type 2 diabetes, such as maintaining a healthy body weight, eating healthily, avoiding tobacco and being active for 150 minutes per week. Methods We used a qualitative methodology informed by the capability, opportunity, motivation theory of behaviour change to explore the factors affecting physical activity among men and women in rural Bangladesh. We conducted semi-structured interviews and focus group discussions with 64 purposively sampled participants with and without diabetes, and five health workers. From the results of descriptive content analysis, we identified key capabilities, opportunities and motivations to engage with in our mHealth and community mobilization interventions. Results Men and women without diabetes lacked awareness about the need to remain physically active to prevent diabetes, and most felt that their activity levels were sufficient. Housework was not commonly perceived as physical activity among all respondents. These knowledge and capability gaps could be addressed through mHealth messaging and community mobilization providing information on sufficiency and types of physical activity to prevent and control diabetes. Men were physically active while working outside the home, whereas women felt unsafe and conspicuous, and were constrained by family commitments and social expectations of appropriate behaviour. Women engaged in strategies to protect their own and their family's reputations. These opportunity factors affecting physical activity indicated the need for strategies developed through participatory processes to challenge unhealthy gender norms and increase women's safety. Conclusion Formative research data can enable the development of contextually relevant interventions. Data show that mHealth interventions should consider gendered barriers to physical activity, tailoring information to meet men's and women's needs, and that community mobilization interventions should enable unhealthy, gendered community norms to be challenged. Participatory interventions can enable communities to push the boundaries of socially acceptable behaviours to increase physical activity, helping to prevent and control diabetes.

Implementation and fidelity of a participatory learning and action cycle intervention to prevent and control type 2 diabetes in rural Bangladesh.

INTRODUCTION: There is an urgent need to address the growing type 2 diabetes disease burden. 20-30% of adults in rural areas of Bangladesh have intermediate hyperglycaemia and about 10% have diabetes. We report on the implementation and fidelity of a Participatory Learning and Action (PLA) intervention, evaluated through a three-arm cluster randomised controlled trial which reduced the incidence of diabetes and intermediate hyperglycaemia in rural Bangladesh. PLA interventions have been effective in addressing population level health problems in low income country contexts, and therefore we sought to use this approach to engage communities to identify and address community barriers to prevention and control of type 2 diabetes. METHODS: We used a mixed methods approach collecting quantitative data through field reports and qualitative data through observations and focus group discussions. Through descriptive analysis, we considered fidelity to the participatory approach and implementation plans. RESULTS: One hundred twenty-two groups per month were convened by 16 facilitators and supervised by two coordinators. Groups worked through a four phase PLA cycle of problem identification, planning together, implementation and evaluation to address the risk factors for diabetes - diet, physical activity, smoking and stress. Groups reported a lack of awareness about diabetes prevention and control, the prohibitive cost of care and healthy eating, and gender barriers to exercise for women. Groups set targets to encourage physical activity, kitchen-gardening, cooking with less oil, and reduced tobacco consumption. Anti-tobacco committees operated in 90 groups. One hundred twenty-two groups arranged blood glucose testing and 74 groups organized testing twice. Forty-one women's groups established funds, and 61 communities committed not to ridicule women exercising. Experienced and committed supervisors enabled fidelity to a participatory methodology. A longer intervention period and capacity building could enable engagement with systems barriers to behaviour change. CONCLUSION: Our complex intervention was implemented as planned and is likely to be valid in similar contexts given the flexibility of the participatory approach to contextually specific barriers to prevention and control of type 2 diabetes. Fidelity to the participatory approach is key to implementing the intervention and effectively addressing type 2 diabetes in a low-income country.

Developing a theory-driven contextually relevant mHealth intervention.

Background: mHealth interventions have huge potential to reach large numbers of people in resource poor settings but have been criticised for lacking theory-driven design and rigorous evaluation. This paper shares the process we developed when developing an awareness raising and behaviour change focused mHealth intervention, through applying behavioural theory to in-depth qualitative research. It addresses an important gap in research regarding the use of theory and formative research to develop an mHealth intervention. Objectives: To develop a theory-driven contextually relevant mHealth intervention aimed at preventing and managing diabetes among the general population in rural Bangladesh. Methods: In-depth formative qualitative research (interviews and focus group discussions) were conducted in rural Faridpur. The data were analysed thematically and enablers and barriers to behaviour change related to lifestyle and the prevention of and management of diabetes were identified. In addition to the COM-B (Capability, Opportunity, Motivation-Behaviour) model of behaviour change we selected the Transtheoretical Domains Framework (TDF) to be applied to the formative research in order to guide the development of the intervention. Results: A six step-process was developed to outline the content of voice messages drawing on in-depth qualitative research and COM-B and TDF models. A table to inform voice messages was developed and acted as a guide to scriptwriters in the production of the messages. Conclusions: In order to respond to the local needs of a community in Bangladesh, a process of formative research, drawing on behavioural theory helped in the development of awareness-raising and behaviour change mHealth messages through helping us to conceptualise and understand behaviour (for example by categorising behaviour into specific domains) and subsequently identify specific behavioural strategies to target the behaviour.

Exploring the equity impact of a maternal and newborn health intervention: a qualitative study of participatory women's groups in rural South Asia and Africa.

BACKGROUND: A consensus is developing on interventions to improve newborn survival, but little is known about how to reduce socioeconomic inequalities in newborn mortality in low- and middle-income countries. Participatory learning and action (PLA) through women's groups can improve newborn survival and home care practices equitably across socioeconomic strata, as shown in cluster randomised controlled trials. We conducted a qualitative study to understand the mechanisms that led to the equitable impact of the PLA approach across socioeconomic strata in four trial sites in India, Nepal, Bangladesh, and Malawi. METHODS: We conducted 42 focus group discussions (FGDs) with women who had attended groups and women who had not attended, in poor and better-off communities. We also interviewed six better-off women and nine poor women who had delivered babies during the trials and had demonstrated recommended behaviours. We conducted 12 key informant interviews and five FGDs with women's group facilitators and fieldworkers. RESULTS: Women's groups addressed a knowledge deficit in poor and better-off women. Women were engaged through visual learning and participatory tools, and learned from the facilitator and each other. Facilitators enabled inclusion of all socioeconomic strata, ensuring that strategies were low-cost and that discussions and advice were relevant. Groups provided a social support network that addressed some financial barriers to care and gave women the confidence to promote behaviour change. Information was disseminated through home visits and other strategies. The social process of learning and action, which led to increased knowledge, confidence to act, and acceptability of recommended practices, was key to ensuring behaviour change across social strata. These equitable effects were enabled by the accessibility, relevance, and engaging format of the intervention. CONCLUSIONS: Participatory learning and action led to increased knowledge, confidence to act, and acceptability of recommended practices. The equitable behavioural effects were facilitated by the accessibility, relevance, and engaging format of the intervention across socioeconomic groups, and by reaching-out to parts of the population usually not accessed. A PLA approach improved health behaviours across socioeconomic strata in rural communities, around issues for which there was a knowledge deficit and where simple changes could be made at home.

Community groups or mobile phone messaging to prevent and control type 2 diabetes and intermediate hyperglycaemia in Bangladesh (DMagic): a cluster-randomised controlled trial.

BACKGROUND: Strategies are needed to prevent and control type 2 diabetes and intermediate hyperglycaemia, which together affect roughly a third of adults in Bangladesh. We aimed to assess the effects of mHealth and community mobilisation on the prevalence of intermediate hyperglycaemia and diabetes among the general adult population in rural Bangladesh, and to assess the effect of these interventions on the incidence of type 2 diabetes among people with intermediate hyperglycaemia within the study population. METHODS: DMagic was a three-arm, cluster-randomised trial of participatory community mobilisation, mHealth mobile phone messaging, and usual care (control) in 96 villages (population roughly 125 000) in Bangladesh. Community mobilisation involved 18 monthly group meetings, led by lay facilitators, applying a participatory learning and action (PLA) cycle focused on diabetes prevention and control. mHealth involved twice-weekly voice messages over 14 months promoting behaviour change to reduce diabetes risk. The primary outcomes were the combined prevalence of type 2 diabetes and intermediate hyperglycaemia in the overall population at the end of the intervention implementation period, and 2-year cumulative incidence of type 2 diabetes in a cohort with intermediate hyperglycaemia at baseline. Primary outcomes were assessed through fasting blood glucose concentrations and 2-h oral glucose tolerance tests among a cross-section of adults aged 30 years and older and a cohort of individuals identified with intermediate hyperglycaemia. Prevalence findings are based on a cross-sectional survey at the end of the study; incidence findings are based on 2-year follow-up survey of a cohort of individuals identified with intermediate hyperglycaemia through a cross-sectional survey at baseline. We also assessed the cost-effectiveness of the interventions. This trial is registered with the ISRCTN registry, number ISRCTN41083256, and is completed. FINDINGS: The study took place between June 27, 2015, and June 28, 2018, with the PLA intervention running in 32 villages from June, 2016, to December, 2017, and the mHealth intervention running in 32 villages from Oct 21, 2016, to Dec 24, 2017. End-of study prevalence was assessed in 11 454 individuals and incidence in 2100 individuals. There was a large reduction in the combined prevalence of type 2 diabetes and intermediate hyperglycaemia in the PLA group compared with the control group at the end of the study (adjusted [for stratification, clustering, and wealth] odds ratio [aOR] 0·36 [0·27-0·48]), with an absolute reduction of 20·7% (95% CI 14·6-26·7). Among 2470 adults with intermediate hyperglycaemia at baseline, 2100 (85%) were followed-up at 2 years. The 2-year cumulative incidence of diabetes in this cohort was significantly lower in the PLA group compared with control (aOR 0·39, 0·24-0·65), representing an absolute incidence reduction of 8·7% (3·5-14·0). There was no evidence of effect of mHealth on combined prevalence of intermediate hyperglycaemia and diabetes (aOR 0·93, 0·74-1·16) or the incidence of diabetes (1·02, 0·73-1·43). The incremental cost-effectiveness ratios for PLA were INT$316 per case of intermediate hyperglycaemia or type 2 diabetes prevented and $6518 per case of type 2 diabetes prevented among individuals with intermediate hyperglycaemia. INTERPRETATION: Our data provide strong evidence to support the use of community mobilisation based on PLA to prevent type 2 diabetes in this rural Bangladeshi population. Despite raising knowledge and awareness of diabetes, the mHealth intervention did not change disease outcomes in our population. Replication studies in other populations should be a priority. FUNDING: UK Medical Research Council.