A Fluorination Strategy and Low-Acidity Anchoring Group in Self-Assembled Molecules for Efficient and Stable Inverted Perovskite Solar Cells.

Herein, we synthesized two donor-acceptor (D-A) type small organic molecules with self-assembly properties, namely MPA-BT-BA and MPA-2FBT-BA, both containing a low acidity anchoring group, benzoic acid. After systematically investigation, it is found that, with the fluorination, the MPA-2FBT-BA demonstrates a lower highest occupied molecular orbital (HOMO) energy level, higher hole mobility, higher hydrophobicity and stronger interaction with the perovskite layer than that of MPA-BT-BA. As a result, the device based-on MPA-2FBT-BA displays a better crystallization and morphology of perovskite layer with larger grain size and less non-radiative recombination. Consequently, the device using MPA-2FBT-BA as hole transport material achieved the power conversion efficiency (PCE) of 20.32 % and remarkable stability. After being kept in an N2 glove box for 116 days, the unsealed PSCs' device retained 93 % of its initial PCE. Even exposed to air with a relative humidity range of 30±5 % for 43 days, its PCE remained above 91 % of its initial condition. This study highlights the vital importance of the fluorination strategy combined with a low acidity anchoring group in SAMs, offering a pathway to achieve efficient and stable PSCs.

Antisolvent-Free Heterogenous Nucleation Enabled by Employing 4-Tert-Butyl Pyridine Additive and Two-Step Annealing for Efficient CsPbI2 Br Perovskite Solar Cells.

All inorganic perovskite based on CsPbI2 Br has attracted significant attention due to its relatively thermal stable structure compare to its hybrid counterparts. With a wide bandgap of 1.9 eV and excellent light absorption capability, it has been extensively explored for applications in indoor photovoltaics and as a front absorber in tandem devices. However, the uncontrollable crystallization process during solvent evaporation and thermal annealing leads to both macroscopic defects like cracks and microscopic defects such as voids. In this study, a metastable adduct with lead (II) halides by incorporating 4-tert-butyl pyridine as a volatile Lewis base monodentate ligand in the precursor solution is formed. The strategic preferential decomposition of the adduct during the early-stage low-temperature annealing facilitated the desorption of lead (II) halides, inducing antisolvent-free heterogenous nucleation. This, in turn, promoted crystal growth during subsequent high-temperature annealing, resulting in dense films with low defect density. As a result, a maximum open-circuit voltage of 1.30 V is achieved with the champion power conversion efficiency of 16.5% in CsPbI2 Br-based perovskite solar cell. The work reveals a new mechanism of using Lewis acid-base adduct to obtain high quality perovskite films other than hindering crystallization in traditional way.

Characterization of HIV-Related Stigma in Myanmar.

Characterizing HIV-related stigma and its impacts are important for interventions toward their elimination. A cross-sectional study was conducted in 2016 to evaluate enacted and internalized stigma among adult people living with HIV (PLWH) across four cities in Myanmar using the India Stigma Index questionnaire. Multivariable regression analyses were performed to determine differences in measured enacted and internalized stigma outcomes. Among 1,006 participants, 89% reported any stigma indicator, 47% enacted stigma, and 87% internalized stigma. In regression analysis, city and duration of illness were associated with higher enacted stigma, and younger age was associated with higher internalized stigma. Those with HIV duration > 7.4 years had mean enacted stigma nearly 2 units higher than the overall mean. Internalized stigma increased with duration of illness and leveled off at 5 years. PLWH from smaller cities experienced lower stigma. In Myanmar, nearly 90% of PLWH experience stigma, results that reflect a unique transition point.

Single Crystals of Mixed-Cation Copper-Based Perovskite with Trimodal Bandgap Behavior.

Two-dimensional (2D) hybrid perovskites with novel functionalities and structural diversity are a perfect platform for emerging optoelectronic devices such as photodetectors, light-emitting diodes, and solar cells. Here, we demonstrate that excess concentration of Cesium bromide (CsBr) is key to the formation of easily exfoliated 2D Cs2 Cu(Cl/Br)4 perovskite crystal. Furthermore, by employing this trick to 2D perovskite MA2 Cu(Cl/Br)4 (MA=methylammonium), we achieve a phase-pure easily exfoliated 2D mixed-cation (MA/Cs)2 Cu(Cl/Br)4 perovskite crystal, which exhibits reduced bandgap (1.53 eV) with ferromagnetic behavior and photovoltaic property. The resultant mixed-cation structured device reveals enhanced efficiency compared to all MA and all Cs counterparts. These findings demonstrate the importance of cation-engineering in developing innovative materials with novel properties.

Evaluation of peer-to-peer HIV counseling in Myanmar: a measure of knowledge, adherence, and barriers.

In Myanmar, an Asian country with one of the highest HIV-1 prevalence rates, counseling prior to initiating antiretroviral therapy (ART) is standard care, either by a healthcare worker (standard counselor, SC) or trained counselor who is also living with HIV (peer counselor, PC). PC is commonly utilized in Myanmar and other resource-limited settings. However, its benefit over SC is unclear. We conducted a cross-sectional survey of people living with HIV (PLWH), who completed either only PC or only SC before treatment initiation across four cities in Myanmar. Participants were evaluated for HIV knowledge, stigma, antiretroviral adherence, barriers to care, social support satisfaction and attitudes regarding both counseling processes. Bivariate analyses and multivariable mixed effects modeling were conducted to compare differences in these measures among PC and SC participants. Among 1006 participants (49% PC; 51% SC), 52% were females and median age was 37 years in those receiving PC and 40 years in those receiving SC. More than 70% of participants in both groups achieved up to grade school education. The average duration since HIV diagnosis was 4.6 years for PC and 5.7 years for SC participants. HIV knowledge and attitudes regarding counseling were good in both groups and more PC participants credited their HIV counselor for knowledge (75% vs 63%, p < 0.001). Compared to SC, PC participants had lower enacted stigma (Incidence Rate Ratio (IRR) 0.75, Confidence Interval (CI) [0.65, 0.86]), mean internalized stigma (-0.24, CI [-0.34, -0.14]), and risk of antiretroviral therapy non-adherence (Odds Ratio 0.59, CI [0.40, 0.88]), while reporting higher levels of barriers to care (9.63, CI [8.20, 11.75]). Our findings demonstrate potential benefits of PC compared to SC, and support the utilization of PC to enhance HIV health outcomes within the unique societal and geographical context of Myanmar, and possibly beyond.

Revealing the Hidden Mechanism of Enhanced Responsivity of Doped p-i-n Perovskite Photodiodes via Coupled Opto-Electronic Model.

Organic-inorganic halide perovskites have demonstrated preeminent optoelectronic performance in recent years due to their unique material properties, and have shown great potential in the field of photodetectors. In this study, a coupled opto-electronic model is constructed to reveal the hidden mechanism of enhancing the performance of perovskite photodetectors that are suitable for both inverted and regular structure doped p-i-n perovskite photodiodes. Upon illumination, the generation rate of photogenerated carriers is calculated followed by carrier density distribution, which serves as a coupled joint to further analyze the recombination rate, electric field strength, and current density of carriers under different doping types and densities. Moreover, experiments were carried out in which the doping types and densities of the active layer were regulated by changing the precursor ratios. With optimal doping conditions, the inverted and regular perovskite photodiodes achieved an external quantum efficiency of 74.83% and 73.36%, and a responsivity of 0.417 and 0.404 A/W, respectively. The constructed coupled opto-electronic model reveals the hidden mechanism and along with the doping strategy, this study provides important guidance for further analysis and improvement of perovskite-based photodiodes.

Predictors of virological failure among people living with HIV receiving first line antiretroviral treatment in Myanmar: retrospective cohort analysis.

BACKGROUND: Progress toward the global target for 95% virological suppression among those on antiretroviral treatment (ART) is still suboptimal. We describe the viral load (VL) cascade, the incidence of virological failure and associated risk factors among people living with HIV receiving first-line ART in an HIV cohort in Myanmar treated by the Médecins Sans Frontières in collaboration with the Ministry of Health and Sports Myanmar. METHODS: We conducted a retrospective cohort study, including adult patients with at least one HIV viral load test result and having received of at least 6 months' standard first-line ART. The incidence rate of virological failure (HIV viral load ≥ 1000 copies/mL) was calculated. Multivariable Cox's regression was performed to identify risk factors for virological failure. RESULTS: We included 25,260 patients with a median age of 33.1 years (interquartile range, IQR 28.0-39.1) and a median observation time of 5.4 years (IQR 3.7-7.9). Virological failure was documented in 3,579 (14.2%) participants, resulting in an overall incidence rate for failure of 2.5 per 100 person-years of follow-up. Among those who had a follow-up viral load result, 1,258 (57.1%) had confirmed virological failure, of which 836 (66.5%) were switched to second-line treatment. An increased hazard for failure was associated with age ≤ 19 years (adjusted hazard ratio, aHR 1.51; 95% confidence intervals, CI 1.20-1.89; p < 0.001), baseline tuberculosis (aHR 1.39; 95% CI 1.14-1.49; p < 0.001), a history of low-level viremia (aHR 1.60; 95% CI 1.42-1.81; p < 0.001), or a history of loss-to-follow-up (aHR 1.24; 95% CI 1.41-1.52; p = 0.041) and being on the same regimen (aHR 1.37; 95% CI 1.07-1.76; p < 0.001). Cumulative appointment delay was not significantly associated with failure after controlling for covariates. CONCLUSIONS: VL monitoring is an important tool to improve programme outcomes, however limited coverage of VL testing and acting on test results hampers its full potential. In our cohort children and adolescents, PLHIV with history of loss-to-follow-up or those with low-viremia are at the highest risk of virological failure and might require more frequent virological monitoring than is currently recommended.

Chikungunya Virus Infection in Blood Donors and Patients During Outbreak, Mandalay, Myanmar, 2019.

In 2019, an outbreak of chikungunya virus infection occurred in Mandalay, Myanmar, and 3.2% of blood donors and 20.5% of patients who were children were confirmed as being infected. The prevalence rate was up to 6.3% among blood donors. The East Central/South African genotype was predominantly circulating during this outbreak.

High-Performance Inverted Planar Perovskite Solar Cells Enhanced by Thickness Tuning of New Dopant-Free Hole Transporting Layer.

A new hole transporting material (HTM) named DMZ is synthesized and employed as a dopant-free HTM in inverted planar perovskite solar cells (PSCs). Systematic studies demonstrate that the thickness of the hole transporting layer can effectively enhance the morphology and crystallinity of the perovskite layer, leading to low series resistance and less defects in the crystal. As a result, the champion power conversion efficiency (PCE) of 18.61% with JSC = 22.62 mA cm-2 , VOC = 1.02 V, and FF = 81.05% (an average one is 17.62%) is achieved with a thickness of ≈13 nm of DMZ (2 mg mL-1 ) under standard global AM 1.5 illumination, which is ≈1.5 times higher than that of devices based on poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonic acid) (PEDOT:PSS). More importantly, the devices based on DMZ exhibit a much better stability (90% of maximum PCE retained after more than 556 h in air (relative humidity ≈ 45%-50%) without any encapsulation) than that of devices based on PEDOT:PSS (only 36% of initial PCE retained after 77 h in same conditions). Therefore, the cost-effective and facile material named DMZ offers an appealing alternative to PEDOT:PSS or polytriarylamine for highly efficient and stable inverted planar PSCs.

Late Middle Eocene primate from Myanmar and the initial anthropoid colonization of Africa.

Reconstructing the origin and early evolutionary history of anthropoid primates (monkeys, apes, and humans) is a current focus of paleoprimatology. Although earlier hypotheses frequently supported an African origin for anthropoids, recent discoveries of older and phylogenetically more basal fossils in China and Myanmar indicate that the group originated in Asia. Given the Oligocene-Recent history of African anthropoids, the colonization of Africa by early anthropoids hailing from Asia was a decisive event in primate evolution. However, the fossil record has so far failed to constrain the nature and timing of this pivotal event. Here we describe a fossil primate from the late middle Eocene Pondaung Formation of Myanmar, Afrasia djijidae gen. et sp. nov., that is remarkably similar to, yet dentally more primitive than, the roughly contemporaneous North African anthropoid Afrotarsius. Phylogenetic analysis suggests that Afrasia and Afrotarsius are sister taxa within a basal anthropoid clade designated as the infraorder Eosimiiformes. Current knowledge of eosimiiform relationships and their distribution through space and time suggests that members of this clade dispersed from Asia to Africa sometime during the middle Eocene, shortly before their first appearance in the African fossil record. Crown anthropoids and their nearest fossil relatives do not appear to be specially related to Afrotarsius, suggesting one or more additional episodes of dispersal from Asia to Africa. Hystricognathous rodents, anthracotheres, and possibly other Asian mammal groups seem to have colonized Africa at roughly the same time or shortly after anthropoids gained their first toehold there.

General strategy for self-assembly of highly oriented nanocrystalline semiconducting polymers with high mobility.

Solution processable semiconducting polymers with excellent film forming capacity and mechanical flexibility are considered among the most progressive alternatives to conventional inorganic semiconductors. However, the random packing of polymer chains and the disorder of the polymer matrix typically result in low charge transport mobilities (10(-5)-10(-2) cm(2) V(-1) s(-1)). These low mobilities compromise their performance and development. Here, we present a strategy, by utilizing capillary action, to mediate polymer chain self-assembly and unidirectional alignment on nanogrooved substrates. We designed a sandwich tunnel system separated by functionalized glass spacers to induce capillary action for controlling the polymer nanostructure, crystallinity, and charge transport. Using capillary action, we demonstrate saturation mobilities with average values of 21.3 and 18.5 cm(2) V(-1 )s(-1) on two different semiconducting polymers at a transistor channel length of 80 µm. These values are limited by the source-drain contact resistance, Rc. Using a longer channel length of 140 µm where the contact resistance is less important, we measured µh = 36.3 cm(2) v(-1) s(-1). Extrapolating to infinite channel length where Rc is unimportant, the intrinsic mobility for poly[4-(4,4-dihexadecyl-4H-cyclopenta[1,2-b:5,4-b']dithiophen-2-yl)-alt-[1,2,5]thiadiazolo[3,4-c]pyridine] (Mn = 140 kDa) at this degree of chain alignment and structural order is µh ≈ 47 cm(2 )v(-1) s(-1). Our results create a promising pathway toward high performance, solution processable, and low-cost organic electronics.

Detection of east/central/south African genotype of chikungunya virus in Myanmar, 2010.

In 2010, chikungunya virus of the East Central South African genotype was isolated from 4 children in Myanmyar who had dengue-like symptoms. Phylogenetic analysis of the E1 gene revealed that the isolates were closely related to isolates from China, Thailand, and Malaysia that harbor the A226V mutation in this gene.

Microstructured porous ZnO thin film for increased light scattering and improved efficiency in inverted organic photovoltaics.

Microstructured porous zinc oxide (ZnO) thin film was developed and demonstrated as an electron selective layer for enhancing light scattering and efficiency in inverted organic photovoltaics. High degree of porosity was induced and controlled in the ZnO layer by incorporation of polyethylene glycol (PEG) organic template. Scanning electron microscopy, contact angle and absorption measurements prove that the ZnO:PEG ratio of 4:1 is optimal for the best performance of porous ZnO. Ensuring sufficient pore-filling, the use of porous ZnO leads to a marked improvement in device performance compared to non-porous ZnO, with 35% increase in current density and 30% increase in efficiency. Haze factor studies indicate that the performance improvement can be primarily attributed to the improved light scattering enabled by such a highly porous structure.

Improved light harvesting and improved efficiency by insertion of an optical spacer (ZnO) in solution-processed small-molecule solar cells.

We demonstrate that the power conversion efficiency can be significantly improved in solution-processed small-molecule solar cells by tuning the thickness of the active layer and inserting an optical spacer (ZnO) between the active layer and the Al electrode. The enhancement in light absorption in the cell was measured with UV-vis absorption spectroscopy and by measurements of the photoinduced carriers generation rate. The ZnO layer used to improve the light-harvesting increases the charge collection efficiency, serves as a blocking layer for holes, and reduces the recombination rate. The combined optical and electrical improvements raise the power conversion efficiency of solution-processed small-molecule solar cells to 8.9%, that is, comparable to that of polymer counterparts.

N-DMBI Doping of Carbon Nanotube Yarns for Achieving High n-Type Thermoelectric Power Factor and Figure of Merit.

The application of carbon nanotube (CNT) yarns as thermoelectric materials for harvesting energy from low-grade waste heat including that generated by the human body, is attracting considerable attention. However, the lack of efficient n-type CNT yarns hinders their practical implementation in thermoelectric devices. This study reports efficient n-doping of CNT yarns, employing 4-(1, 3-dimethyl-2, 3-dihydro-1H-benzimidazole-2-yl) phenyl) dimethylamine (N-DMBI) in alternative to conventional n-dopants, with o-dichlorobenzene emerging as the optimal solvent. The small molecular size of N-DMBI enables highly efficient doping within a remarkably short duration (10 s) while ensuring prolonged stability in air and at high temperature (150 °C). Furthermore, Joule annealing of the yarns significantly improves the n-doping efficiency. Consequently, thermoelectric power factors (PFs) of 2800, 2390, and 1534 µW m-1  K-2 are achieved at 200, 150, and 30 °C, respectively. The intercalation of N-DMBI molecules significantly suppresses the thermal conductivity, resulting in the high figure of merit (ZT) of 1.69×10-2 at 100 °C. Additionally, a π-type thermoelectric module is successfully demonstrated incorporating both p- and n-doped CNT yarns. This study offers an efficient doping strategy for achieving CNT yarns with high thermoelectric performance, contributing to the realization of lightweight and mechanically flexible CNT-based thermoelectric devices.

Biochemical and biological characterization of the venoms of Naja kaouthia and Naja mandalayensis from Myanmar and neutralization effects of BPI cobra antivenom.

Snakebite is a neglected public health issue, with many scientific and medical issues to be solved. Cobras are among the most common venomous snakes in Myanmar and are responsible for a considerable number of severe snakebite envenoming. There are three species of cobra (Naja kaouthia, Naja mandalayensis and Ophiophagus hannah) in Myanmar. The study aims to characterize the N. kaouthia and N. mandalayensis venoms and to investigate the efficacy of anti-cobra antivenom (BPI) against the two venoms. Protein components and fibrinogenolytic activity were determined by SDS-PAGE. Enzymatic activities for PLA2, protease and acetylcholinesterase were determined by spectrophotometric method. Anticoagulant activity was determined by recalcification time of citrated human plasma. Myotoxicity, necrotizing activity, median lethal dose (LD50) and median effective dose (ED50) were determined by WHO recommended methods. The SDS-PAGE displayed the proteins and enzymes containing in two venoms were different. N. kaouthia venom exhibited more in PLA2, acetylcholinesterase, anticoagulant, fibrinogenolytic and necrotizing activities than N. mandalayensis venom. N. mandalayensis venom had more protease activity and myotoxicity than N. kaouthia venom. The median lethal dose (LD50) of N. kaouthia and N. mandalayensis venom was 4.33 µg/mouse and 5.04 µg/mouse respectively. Both venoms induced fibrinogen Aα chain degradation in 30 min (N. kaouthia) and in 6 h (N. mandalayensis). The same median effective dose (ED50) (19.56 µg/mouse) showed that anti-NK antivenom can neutralize against lethal effect of N. mandalayensis venom. It can also neutralize the protease activity, anticoagulant activity and fibrinogenolytic activity of both venoms. Immunodiffusion and immunoblotting studies showed that the antivenom recognized its homologous venom (N. kaouthia) and cross-reacted against the heterologous venom (N. mandalayensis). The anti-NK antivenom is suitable to use for N. mandalayensis bite if monospecific antivenom is not available.

Enhancing the Performance of Perovskite Light-Emitting Diodes via Synergistic Effect of Defect Passivation and Dielectric Screening.

Metal halide perovskites, particularly the quasi-two-dimensional perovskite subclass, have exhibited considerable potential for next-generation electroluminescent materials for lighting and display. Nevertheless, the presence of defects within these perovskites has a substantial influence on the emission efficiency and durability of the devices. In this study, we revealed a synergistic passivation mechanism on perovskite films by using a dual-functional compound of potassium bromide. The dual functional potassium bromide on the one hand can passivate the defects of halide vacancies with bromine anions and, on the other hand, can screen the charged defects at the grain boundaries with potassium cations. This approach effectively reduces the probability of carriers quenching resulting from charged defects capture and consequently enhances the radiative recombination efficiency of perovskite thin films, leading to a significant enhancement of photoluminescence quantum yield to near-unity values (95%). Meanwhile, the potassium bromide treatment promoted the growth of homogeneous and smooth film, facilitating the charge carrier injection in the devices. Consequently, the perovskite light-emitting diodes based on this strategy achieve a maximum external quantum efficiency of ~ 21% and maximum luminance of ~ 60,000 cd m-2. This work provides a deeper insight into the passivation mechanism of ionic compound additives in perovskite with the solution method.

Correction: Viraemic-time predicts mortality among people living with HIV on second-line antiretroviral treatment in Myanmar: A retrospective cohort study.

[This corrects the article DOI: 10.1371/journal.pone.0271910.].

Adherence to COVID-19 preventive measures among residents in selected townships, Yangon Region, Myanmar: a community-based cross-sectional study.

BACKGROUND: To fight the current coronavirus disease (COVID-19) pandemic, many countries have implemented various mitigation measures to contain the spread of the disease. By engaging with health service providers, the community's participation in adherence to preventive measures is certainly required in the implementation of COVID-19 mitigation strategies. Therefore, this study aimed to assess the level of adherence to COVID-19 preventive measures and its associated factors among the residents, Yangon Region, Myanmar. METHODS: A community-based cross-sectional study was carried out among 636 residents in Yangon Region, Myanmar, from October to December 2021. A multistage non-probability sampling method, purposively selected for three townships in Yangon Region and convenience sampling for 212 participants from each township, was applied and the data were collected by face-to-face interviews using structured and pretested questionnaires. Data were entered, coded, and analyzed using IBM SPSS version 25.0. Simple and multiple logistic regression analysis were performed to identify the significant variables of adherence to COVID-19 preventive measures. RESULTS: As a level of adherence to COVID-19 preventive measures, the proportion of residents who had good adherence was 39.3% (95% CI 35.5-43.2%), moderate adherence was 37.6% (95% CI 33.8-41.5%), and poor adherence was 23.1% (95% CI 19.9-26.6%). The age group of 31-40 years (AOR: 3.13, 95% CI 1.62-6.05), 30 years and younger (AOR: 3.22, 95% CI 1.75-5.92), Burmese ethnicity (AOR: 2.52, 95% CI 1.44-4.39), own business (AOR: 3.19, 95% CI 1.15-8.87), high school education level and below (AOR: 1.64, 95% CI 1.02-2.69), less than 280.90 USD of monthly family income (AOR: 1.51, 95% CI 1.01-2.29), low knowledge about COVID-19 (AOR: 1.90, 95% CI 1.26-2.88) were significantly associated with poor adherence to COVID-19 preventive measures. CONCLUSIONS: In this study, nearly one-fourth of the residents were experiencing poor adherence to COVID-19 preventive measures. Therefore, building up the risk communication through the community using widely used mainstream media, the continuation of disease surveillance and announcement of updated information or advice for the public to increase awareness towards COVID-19, and enforcement to follow the recommended directions and regulations of health institutions are vital to consider for improving the adherence to preventive measures against COVID-19 among the residents.

Benzophenone: A Small Molecule Additive for Enhanced Performance and Stability of Inverted Perovskite Solar Cells.

In this study, we investigated the impact of benzophenone (BP), a small molecule additive, on the performance and stability of inverted perovskite solar cells (PSCs). Specifically, we introduced BP into the perovskite precursor solution of FAPbI3 to fabricate PSCs with an ITO/PEDOT:PSS/BP:FAPbI3/PCBM/C60/PCB/Ag architecture. The incorporation of BP with an optimum concentration of 2 mg mL-1 significantly enhanced the power conversion efficiency (PCE) of the inverted PSC from 13.12 to 18.84% with negligible hysteresis. Notably, the BP-based PSCs retained ∼90% of their initial PCE after being stored in ambient air with 30% relative humidity at 25 °C for 700 h. In contrast, control devices showed rapid degradation, retaining only 30% of their initial value within 300 h under the same conditions. We attributed the superior performance and stability of the BP-based PSCs to the grain boundary passivation of the perovskite film. The improvement was mainly attributed to the intermolecular interaction between the O-donor Lewis base BP material and both Pb2+ and FA+ in FAPbI3. This effectively suppresses trap-assisted recombination and promotes the conversion of the δ-phase to photoactive and stable α-phase FAPbI3. Overall, our findings suggest that BP is a promising additive for improving the performance and stability of inverted PSCs.