Untying the insulating and superconducting orders in magic-angle graphene.

The coexistence of superconducting and correlated insulating states in magic-angle twisted bilayer graphene1-11 prompts fascinating questions about their relationship. Independent control of the microscopic mechanisms that govern these phases could help uncover their individual roles and shed light on their intricate interplay. Here we report on direct tuning of electronic interactions in this system by changing the separation distance between the graphene and a metallic screening layer12,13. We observe quenching of correlated insulators in devices with screening layer separations that are smaller than the typical Wannier orbital size of 15 nanometres and with twist angles that deviate slightly from the magic angle of 1.10 ± 0.05 degrees. Upon extinction of the insulating orders, the vacated phase space is taken over by superconducting domes that feature critical temperatures comparable to those in devices with strong insulators. In addition, we find that insulators at half-filling can reappear in small out-of-plane magnetic fields of 0.4 tesla, giving rise to quantized Hall states with a Chern number of 2. Our study suggests re-examination of the often-assumed 'parent-and-child' relation between the insulating and superconducting phases in moiré graphene, and suggests a way of directly probing the microscopic mechanisms of superconductivity in strongly correlated systems.

Superconductors, orbital magnets and correlated states in magic-angle bilayer graphene.

Superconductivity can occur under conditions approaching broken-symmetry parent states1. In bilayer graphene, the twisting of one layer with respect to the other at 'magic' twist angles of around 1 degree leads to the emergence of ultra-flat moiré superlattice minibands. Such bands are a rich and highly tunable source of strong-correlation physics2-5, notably superconductivity, which emerges close to interaction-induced insulating states6,7. Here we report the fabrication of magic-angle twisted bilayer graphene devices with highly uniform twist angles. The reduction in twist-angle disorder reveals the presence of insulating states at all integer occupancies of the fourfold spin-valley degenerate flat conduction and valence bands-that is, at moiré band filling factors ν = 0, ±1, ±2, ±3. At ν ≈ -2, superconductivity is observed below critical temperatures of up to 3 kelvin. We also observe three new superconducting domes at much lower temperatures, close to the ν = 0 and ν = ±1 insulating states. Notably, at ν = ± 1 we find states with non-zero Chern numbers. For ν = -1 the insulating state exhibits a sharp hysteretic resistance enhancement when a perpendicular magnetic field greater than 3.6 tesla is applied, which is consistent with a field-driven phase transition. Our study shows that broken-symmetry states, interaction-driven insulators, orbital magnets, states with non-zero Chern numbers and superconducting domes occur frequently across a wide range of moiré flat band fillings, including close to charge neutrality. This study provides a more detailed view of the phenomenology of magic-angle twisted bilayer graphene, adding to our evolving understanding of its emergent properties.

Observation of Reentrant Correlated Insulators and Interaction-Driven Fermi-Surface Reconstructions at One Magnetic Flux Quantum per Moiré Unit Cell in Magic-Angle Twisted Bilayer Graphene.

The discovery of flat bands with nontrivial band topology in magic-angle twisted bilayer graphene (MATBG) has provided a unique platform to study strongly correlated phenomena including superconductivity, correlated insulators, Chern insulators, and magnetism. A fundamental feature of the MATBG, so far unexplored, is its high magnetic field Hofstadter spectrum. Here, we report on a detailed magnetotransport study of a MATBG device in external magnetic fields of up to B=31 T, corresponding to one magnetic flux quantum per moiré unit cell Φ_{0}. At Φ_{0}, we observe reentrant correlated insulators at a flat band filling factors of ν=+2 and of ν=+3, and interaction-driven Fermi-surface reconstructions at other fillings, which are identified by new sets of Landau levels originating from these. These experimental observations are supplemented by theoretical work that predicts a new set of eight well-isolated flat bands at Φ_{0}, of comparable band width, but with different topology than in zero field. Overall, our magnetotransport data reveal a qualitatively new Hofstadter spectrum in MATBG, which arises due to the strong electronic correlations in the reentrant flat bands.

Effect of thermal and non-thermal processing on astringency reduction and nutrient retention in cashew apple fruit and its juice.

The present study is aimed at evaluating the effect of different processing techniques on astringency reduction, nutrient retention, and sensory attributes in cashew apple fruit and its juice. Astringency attribute was measured by tannin content, while nutrition profile by ascorbic acid, total sugars, and antioxidant activity. Hot water, steaming, and microwave were selected as the source of heat application for treating whole fruit, where the process variables were the temperature and exposure time. The non-thermal technique selected to treat juice was by using bio coagulants, i.e., dried okra pod and drumstick seed powder, where the independent parameters were concentration and settling time. The processes were optimized using a multivariate approach coupled with full factorial design. The obtained results indicated that samples, with 42.6% tannin removal, were rated as being the least astringent. The use of dried okra pod powder under optimal conditions (0.3% concentration, 0.5 h settling time) was found to be the best in reducing astringency while retaining the nutrient and desirable sensory attributes. Maximum tannin removal (48.9 ± 1.6%) with minimum loss of ascorbic acid (8.1 ± 0.9%), total sugar (4.8 ± 0.5%) and antioxidant activity (11.1 ± 1.0) with high sensory score (92.7 ± 1.6%) was achieved with composite desirability of 0.85.

Looking for medium-term conservation and development impacts of community management agreements in Uganda's Rwenzori Mountains National Park.

We evaluate the impact of collaborative management agreements (CMAs) designed to protect forests and raise incomes for smallholders living adjacent to Rwenzori Mountains National Park (RMNP), Uganda. We use a quasi-experimental study design to estimate changes in several income measures, as well as land cover using three waves (2003, 2007, and 2012) of household survey and remote sensing data. Overall, we find no significant impact of CMAs on any of our income measures. However, when disaggregating households by income quartile, we find that access to forest resources in RMNP may have had an income stabilizing effect for poor households. Forest income grew significantly faster among the poorest quartile of treatment relative to control households, partially because poor households recorded very low income from forests at baseline. The effect of CMAs on forest cover is minimal, although we find that conversion of woody savanna and savanna to cropland is more pronounced in villages with CMAs. These findings suggest that in the medium-term, CMAs have failed to deliver conservation or development benefits related to enhancing livelihoods or conserving forests near RMNP. Practitioners should consider different CMA models or other strategies for improving welfare and forest health outcomes in communities neighboring protected areas.

Piloting improved cookstoves in India.

Despite the potential of improved cookstoves to reduce the adverse environmental and health impacts of solid fuel use, their adoption and use remains low. Social marketing-with its focus on the marketing mix of promotion, product, price, and place-offers a useful way to understand household behaviors and design campaigns to change biomass fuel use. We report on a series of pilots across 3 Indian states that use different combinations of the marketing mix. We find sales varying from 0% to 60%. Behavior change promotion that combined door-to-door personalized demonstrations with information pamphlets was effective. When given a choice amongst products, households strongly preferred an electric stove over improved biomass-burning options. Among different stove attributes, reduced cooking time was considered most valuable by those adopting a new stove. Households clearly identified price as a significant barrier to adoption, while provision of discounts (e.g., rebates given if households used the stove) or payments in installments were related to higher purchase. Place-based factors such as remoteness and nongovernmental organization operations significantly affected the ability to supply and convince households to buy and use improved cookstoves. Collectively, these pilots point to the importance of continued and extensive testing of messages, pricing models, and different stove types before scale-up. Thus, we caution that a one-size-fits-all approach will not boost improved cookstove adoption.

Estuarine mangrove niches select cultivable heterotrophic diazotrophs with diverse metabolic potentials-a prospective cross-dialog for functional diazotrophy.

Introduction: Biological nitrogen fixation (BNF), an unparalleled metabolic novelty among living microorganisms on earth, globally contributes ~88-101 Tg N year-1 to natural ecosystems, ~56% sourced from symbiotic BNF while ~22-45% derived from free-living nitrogen fixers (FLNF). The success of symbiotic BNF is largely dependent on its interaction with host-plant, however ubiquitous environmental heterotrophic FLNFs face many limitations in their immediate ecological niches to sustain unhindered BNF. The autotrophic FLNFs like cyanobacteria and oceanic heterotrophic diazotrophs have been well studied about their contrivances acclimated/adapted by these organisms to outwit the environmental constraints for functional diazotrophy. However, FLNF heterotrophs face more adversity in executing BNF under stressful estuarine/marine/aquatic habitats. Methods: In this study a large-scale cultivation-dependent investigation was accomplished with 190 NCBI accessioned and 45 non-accessioned heterotrophic FLNF cultivable bacterial isolates (total 235) from halophilic estuarine intertidal mangrove niches of Indian Sundarbans, a Ramsar site and UNESCO proclaimed World Heritage Site. Assuming ~1% culturability of the microbial community, the respective niches were also studied for representing actual bacterial diversity via cultivation-independent next-generation sequencing of V3-V4 rRNA regions. Results: Both the studies revealed a higher abundance of culturable Gammaproteobacteria followed by Firmicutes, the majority of 235 FLNFs studied belonging to these two classes. The FLNFs displayed comparable selection potential in media for free nitrogen fixers and iron-oxidizing bacteria, linking diazotrophy with iron oxidation, siderophore production, phosphorus solubilization, phosphorus uptake and accumulation as well as denitrification. Discussion: This observation validated the hypothesis that under extreme estuarine mangrove niches, diazotrophs are naturally selected as a specialized multidimensional entity, to expedite BNF and survive. Earlier metagenome data from mangrove niches demonstrated a microbial metabolic coupling among C, N, P, S, and Fe cycling in mangrove sediments, as an adaptive trait, evident with the co-abundant respective functional genes, which corroborates our findings in cultivation mode for multiple interrelated metabolic potential facilitating BNF in a challenging intertidal mangrove environment.

Ecological restoration at pilot-scale employing site-specific rationales for small-patch degraded mangroves in Indian Sundarbans.

To date, degraded mangrove ecosystem restoration accomplished worldwide primarily aligns towards rehabilitation with monotypic plantations, while ecological restoration principles are rarely followed in these interventions. However, researchers admit that most of these initiatives' success rate is not appreciable often. An integrative framework of ecological restoration for degraded mangroves where site-specific observations could be scientifically rationalized, with co-located reference pristine mangroves as the target ecosystem to achieve is currently distinctively lacking. Through this experimental scale study, we studied the suitability of site-specific strategies to ecologically restore degraded mangrove patches vis-à-vis the conventional mono-species plantations in a highly vulnerable mangrove ecosystem in Indian Sundarbans. This comprehensive restoration framework was trialed in small discrete degraded mangrove patches spanning ~ 65 ha. Site-specific key restoration components applied are statistically validated through RDA analyses and Bayesian t-tests. 25 quantifiable metrics evaluate the restoration success of a ~ 3 ha degraded mangrove patch with Ridgeline distribution, Kolmogorov-Smirnov (K-S) tests, and Mahalanobis Distance (D2) measure to prove the site's near-equivalence to pristine reference in multiple ecosystem attributes. This restoration intervention irrevocably establishes the greater potential of this framework in the recovery of ecosystem functions and self-sustenance compared to that of predominant monoculture practices for vulnerable mangroves.

Biochemical and histopathological alterations in freshwater fish, Labeo rohita (Hamilton, 1822) upon chronic exposure to a commonly used hopper insecticide, triflumezopyrim.

The present study has been carried out to see the long-term effects of triflumezopyrim in an Indian major carp, Labeo rohita. Fishes were exposed to sub-lethal concentrations triflumezopyrim insecticide, 1.41 ppm (Treatment 1), 3.27 ppm (Treatment 2) and 4.97 ppm (Treatment 3), respectively for 21 days. The liver, kidney, gills, muscle, and brain tissues of the fish were examined for physiological parameters and biochemical parameters such as catalase (CAT), superoxide dismutase (SOD), lactate dehydrogenase (LDH), malate dehydrogenase (MDH), alanine aminotransaminase (ALT), aspartate aminotransaminase (AST), acetylcholinessterase (AChE), and hexokinase. After 21 days of exposure, the activity CAT, SOD, LDH, MDH and ALT got increased and a drop in the activity of total protein was found in all treatment groups in comparison to the control group. Long-term triflumezopyrim exposure increased ROS production, ultimately leading to oxidative cell damage and inhibiting the antioxidant capabilities of the fish tissues. Histopathological analysis showed alteration in different tissues structures of pesticide treated fishes. Fishes exposed to highest sublethal concentration of the pesticide showed higher damage rate. The present study demonstrated that chronic exposure of fish to different sublethal concentration of triflumezopyrim exerts detrimental effect on the organism.

Poly- and Perfluoroalkyl Substances (PFAS): Do They Matter to Aquatic Ecosystems?

Poly- and perfluoroalkyl substances (PFASs) are a group of anthropogenic chemicals with an aliphatic fluorinated carbon chain. Due to their durability, bioaccumulation potential, and negative impacts on living organisms, these compounds have drawn lots of attention across the world. The negative impacts of PFASs on aquatic ecosystems are becoming a major concern due to their widespread use in increasing concentrations and constant leakage into the aquatic environment. Furthermore, by acting as agonists or antagonists, PFASs may alter the bioaccumulation and toxicity of certain substances. In many species, particularly aquatic organisms, PFASs can stay in the body and induce a variety of negative consequences, such as reproductive toxicity, oxidative stress, metabolic disruption, immunological toxicity, developmental toxicity, cellular damage and necrosis. PFAS bioaccumulation plays a significant role and has an impact on the composition of the intestinal microbiota, which is influenced by the kind of diet and is directly related to the host's well-being. PFASs also act as endocrine disruptor chemicals (EDCs) which can change the endocrine system and result in dysbiosis of gut microbes and other health repercussions. In silico investigation and analysis also shows that PFASs are incorporated into the maturing oocytes during vitellogenesis and are bound to vitellogenin and other yolk proteins. The present review reveals that aquatic species, especially fishes, are negatively affected by exposure to emerging PFASs. Additionally, the effects of PFAS pollution on aquatic ecosystems were investigated by evaluating a number of characteristics, including extracellular polymeric substances (EPSs) and chlorophyll content as well as the diversity of the microorganisms in the biofilms. Therefore, this review will provide crucial information on the possible adverse effects of PFASs on fish growth, reproduction, gut microbial dysbiosis, and its potential endocrine disruption. This information aims to help the researchers and academicians work and come up with possible remedial measures to protect aquatic ecosystems as future works need to be focus on techno-economic assessment, life cycle assessment, and multi criteria decision analysis systems that screen PFAS-containing samples. New innovative methods requires further development to reach detection at the permissible regulatory limits.

Tenets in Microbial Endocrinology: A New Vista in Teleost Reproduction.

Climate vulnerability and induced changes in physico-chemical properties of aquatic environment can bring impairment in metabolism, physiology and reproduction in teleost. Variation in environmental stimuli mainly acts on reproduction by interfering with steroidogenesis, gametogenesis and embryogenesis. The control on reproductive function in captivity is essential for the sustainability of aquaculture production. There are more than 3,000 teleost species across the globe having commercial importance; however, adequate quality and quantity of seed production have been the biggest bottleneck. Probiotics are widely used in aquaculture as a growth promoter, stress tolerance, pathogen inhibition, nutrient digestibility and metabolism, reproductive performance and gamete quality. As the gut microbiota exerts various effects on the intestinal milieu which influences distant organs and pathways, therefore it is considered to be a full-fledged endocrine organ. Researches on Gut-Brain-Gonad axis (GBG axis) and its importance on physiology and reproduction have already been highlighted for higher mammals; however, the study on fish physiology and reproduction is limited. While looking into the paucity of information, we have attempted to review the present status of microbiome and its interaction between the brain and gut. This review will address a process of the microbiome physiological mechanism involved in fish reproduction. The gut microbiota influences the BPG axis through a wide variety of compounds, including neuropeptides, neurotransmitter homologs and transmitters. Currently, research is being conducted to determine the precise process by which gut microbial composition influences brain function in fish. The gut-brain bidirectional interaction can influence brain biochemistry such as GABA, serotonin and tryptophan metabolites which play significant roles in CNS regulation. This review summarizes the fact, how microbes from gut, skin and other parts of the body influence fish reproduction through the Gut-Brain-Gonad axis.

Quantum-noise-limited microwave amplification using a graphene Josephson junction.

Josephson junctions (JJs) and their tunable properties, including their nonlinearities, play an important role in superconducting qubits and amplifiers. JJs together with the circuit quantum electrodynamics architecture form many key components of quantum information processing1. In quantum circuits, low-noise amplification of feeble microwave signals is essential, and Josephson parametric amplifiers (JPAs)2 are the widely used devices. The existing JPAs are based on Al-AlOx-Al tunnel junctions realized in a superconducting quantum interference device geometry, where magnetic flux is the knob for tuning the frequency. Recent experimental realizations of two-dimensional (2D) van der Waals JJs3-5 provide an opportunity to implement various circuit quantum electrodynamics devices6-8 with the added advantage of tuning the junction properties and the operating point using a gate potential. While other components of a possible 2D van der Waals circuit quantum electrodynamics architecture have been demonstrated, a quantum-noise-limited amplifier, an essential component, has not been realized, to the best of our knowledge. Here we implement a quantum-noise-limited JPA using a graphene JJ, that has a linear resonance gate tunability of 3.5 GHz. We report 24 dB amplification with 10 MHz bandwidth and -130 dBm saturation power, a performance on par with the best single-junction JPAs2,9. Importantly, our gate-tunable JPA works in the quantum-limited noise regime, which makes it an attractive option for highly sensitive signal processing. Our work has implications for novel bolometers; the low heat capacity of graphene together with JJ nonlinearity can result in an extremely sensitive microwave bolometer embedded inside a quantum-noise-limited amplifier. In general, this work will open up the exploration of scalable device architectures of 2D van der Waals materials by integrating a sensor with the quantum amplifier.

The benefits of action to reduce household air pollution (BAR-HAP) model: A new decision support tool.

Cooking with polluting and inefficient fuels and technologies is responsible for a large set of global harms, ranging from health and time losses among the billions of people who are energy poor, to environmental degradation at a regional and global scale. This paper presents a new decision-support model-the BAR-HAP Tool-that is aimed at guiding planning of policy interventions to accelerate transitions towards cleaner cooking fuels and technologies. The conceptual model behind BAR-HAP lies in a framework of costs and benefits that is holistic and comprehensive, allows consideration of multiple policy interventions (subsidies, financing, bans, and behavior change communication), and realistically accounts for partial adoption and use of improved cooking technology. It incorporates evidence from recent efforts to characterize the relevant set of parameters that determine those costs and benefits, including those related to intervention effectiveness. Practical aspects of the tool were modified based on feedback from a pilot testing workshop with multisectoral users in Nepal. To demonstrate the functionality of the BAR-HAP tool, we present illustrative calculations related to several cooking transitions in the context of Nepal. In accounting for the multifaceted nature of the issue of household air pollution, the BAR-HAP model is expected to facilitate cross-sector dialogue and problem-solving to address this major health, environment and development challenge.

Genetic control of reproductive and fruit quality traits in crosses involving cultivars and induced mutants of tomato (Solanum lycopersicum L.).

Development of mutants and their effective utilization to incorporate desirable traits in tomato would be a sound improvement strategy to develop so called 'smart' tomato variety of the coming century. Initially we developed three induced mutants from two varieties, 'Patharkuchi', a local adapted cultivar and an introduced variety 'Berika', and then three crosses (Berika 9 P Mut-5, Berika 9 P Mut-11, Patharkuchi 9 B Mut-1) were made to involve in these two varieties and their respective mutants. Six generations (P1, P2, F1, F2, BC1 and BC2) of three crosses were utilized to study the genetic control of yield and quality traits, and to study the genetic basis of formation of dark green fruit. The nature and magnitude of gene action controlling the inheritance of 27 quantitative traits differed from one cross to another and from one trait to another, mostly conditioned by nonadditive gene action and duplicate epistasis. The prevalence of duplicate epistasisin three crosses for most of the traits revealed that the pace of progress through conventional selection process would be hindered as this kind of epistasis might result in decreased variation in F2 and subsequent generations. Recurrent selection in biparental progenies would be helpful for exploiting this type of nonallelic interaction through generation of high frequency of desirable recombination and concentration of genes having cumulative effects in the population. We also observed complex genetic behaviour of some of the traits revealing significant epistatic components. Inheritance study of 'dark green fruit' (dg1) of Berika 9 P Mut-5 cross revealed a single recessive gene governing the trait and expressed when the mutant gene was in homozygous recessive condition (designated as dg-1/dg-1).

Early Adoption of an Improved Household Energy System in Urban Rwanda.

Cooking with solid fuels and inefficient cookstoves has adverse consequences for health, environment, and human well-being. Despite the promise of improved cookstoves to reduce these impacts, adoption rates are relatively low. Using a 2-wave sample of 144 households from the baseline and first midline of an ongoing 4-year randomized controlled trial in Rwanda, we analyze the drivers and associations of early adoption of a household energy intervention marketed by a private sector firm. Households sign an annual contract to purchase sustainably produced biomass pellets and lease a fan micro-gasification cookstove with verified emissions reductions in laboratory settings. Using difference-in-differences and fixed effects estimation techniques, we examine the association between take-up of the improved cooking system and household fuel expenditures, health outcomes, and time use for primary cooks. Thirty percent of households adopted the pellet and improved cookstove system. Adopting households had more assets, lower per capita total expenditures and cooking fuel expenditures, and higher per capita hygiene expenditures. Households with married household heads and female cooks were significantly more likely to adopt. Adjusting for confounders, we find significant reduction in primary cooks' systolic blood pressure, self-reported prevalence of shortness of breath, an indicator of respiratory illness, time spent cooking, and household expenditures on charcoal. Our findings have implications for marketing of future clean fuel and improved cookstove programs in urban settings or where stoves and fuel are purchased. Analysis of follow-up surveys will allow for estimation of long-term impacts of adoption of interventions involving pellets and fan micro-gasification cookstoves.

Implementation and scale-up of a biomass pellet and improved cookstove enterprise in Rwanda.

This paper reviews the experience of a for-profit firm in Rwanda promoting biomass pellets and a fan micro-gasification improved cookstove as a clean cooking alternative to charcoal. Consumers purchase locally produced biomass pellets and receive the improved cookstove on a lease basis. The cost of the pellets and stove(s) is lower than the cost of cooking with charcoal in the urban setting where our study takes place. Inyenyeri has been piloting its business model since 2012. Using data from an ongoing quantitative impact evaluation study, focus group discussions, and a series of key informant interviews, we chronicle the firm's experience with stove choice, pellet production, and marketing, highlighting lessons for the design of private sector led clean cooking interventions We find that 38% of households marketed to as part of our ongoing impact evaluation study adopted the pellet and stove system, but that approximately 45% of those who adopted suspended contracts after signing up. The firm's experience with stove choice, pellet production, pricing structures, and customer service strategies have influenced implementation, adoption rates, and scale-up. Customer preferences for specific stove attributes and willingness of stove manufacturers to modify stoves for local conditions have influenced both the firm's choice of stove and customer satisfaction. In 2015 the firm transitioned customers from the Philips stove to the Mimi Moto, a decision which created confusion among consumers, and affected adoption rates. Despite the challenge of establishing and scaling-up pellet production in central Africa, the firm increased production 400% between 2014 and 2017 to reach 800,000 kg/year. Importing and maintaining pelletizing equipment in Rwanda is costly, the supply of feedstock, and undercapitalization of the firm have affected production. With respect to marketing, after experimenting with a sign-up fee and a minimum monthly purchase of pellets, the firm has decided to transition to a pay-as-you-go system to reduce perceived risk by consumers. A high-level of customer service including in home visits, free in-home repair, and home delivery of pellets are major innovations. The long pilot phase and the evolutionary nature of the firm's activities illustrate both the complexity of building a market for clean cooking, and the time required to understand nascent markets and consumer demand.

A 'burning opportunity' for human rights: using human rights as a catalyst for policies to mitigate the health risk of household air pollution.

With over 3 billion people dependent on traditional cooking and heating technologies, efforts to address the health burden of exposure to household air pollution (HAP), as well as other sociodemographic impacts associated with energy poverty, are central to sustainable development objectives. Yet despite overwhelming scientific consensus on the health burden of HAP exposure, particularly harms to impoverished women and children in developing countries, advocates currently lack a human rights framework to mitigate HAP exposure through improved access to cleaner household energy systems. This article examines the role of human rights in framing state obligations to mitigate HAP exposure, supporting environmental health for the most vulnerable through intersectional obligations across the human right to health, the collective right to development, and women's and children's rights. Drawing from human rights advocacy employed in confronting the public health harms of tobacco, we argue that rights-based civil society advocacy can structure the multi-sectoral policies necessary to address the impacts of HAP exposure and energy poverty, facilitating accountability for human rights implementation through international treaty bodies, national judicial challenges and local political advocacy. We conclude that there is a pressing need to build civil society capacity for a rights-based approach to cleaner household energy policy as a means to alleviate the environmental health effects of energy poverty.

Household air pollution (HAP), microenvironment and child health: Strategies for mitigating HAP exposure in urban Rwanda.

Exposure to household air pollution (HAP) from cooking and heating with solid fuels is major risk factor for morbidity and mortality in sub-Saharan Africa. Children under five are particularly at risk for acute lower respiratory infection. We use baseline data from randomized controlled trial evaluating a household energy intervention in Gisenyi, Rwanda to investigate the role of the microenvironment as a determinant of children's HAP-related health symptoms. Our sample includes 529 households, with 694 children under five. We examine the association between likelihood of HAP-related health symptom prevalence and characteristics of the microenvironment including: dwelling and cooking area structure; distance to nearest road; and tree cover. We find that children residing in groups of enclosed dwellings, in households that cook indoors, and in households proximate to tree cover, are significantly more likely to experience symptoms of respiratory infection, illness with cough and difficulty breathing. On the other hand, children in households with cemented floors and ventilation holes in the cooking area, are significantly less likely to experience the same symptoms. Our findings suggest that in addition to promoting increased access to clean cooking technologies, there are important infrastructure and micro-environment related interventions that mitigate HAP exposure.

Identification of therapeutic targets for inflammation in sickle cell disease (SCD) among Indian patients using gene expression data analysis.

Sickle cell disease (SCD) is life-threatening hemoglobinopathy prevalent in India, Sub-Saharan Africa and Middle East. Inflammation plays a pivotal role in disease process and involves intricate interaction among leukocytes, platelets, sickle erythrocytes and vascular endothelium. Available disease modifying therapies are hydroxyl-urea and blood transfusion. Therefore, it is of interest to develop improved pharmacological agents for SCD. We report up-regulated genes in steady state and vaso-occlusive crisis using analysis of gene expression data obtained by microarray experiment for SCD as potential targets. The association of these targets with inflammation in pathway analysis is also documented.

Biomass Cooking Fuels and Health Outcomes for Women in Malawi.

In sub-Saharan Africa, biomass fuels account for approximately 90% of household energy consumption. Limited evidence exists on the association between different biomass fuels and health outcomes. We report results from a cross-sectional sample of 655 households in Malawi. We calculated odds ratios between hypothesized determinants of household air pollution (HAP) exposure (fuel, stove type, and cooking location) and five categories of health outcomes (cardiopulmonary, respiratory, neurologic, eye health, and burns). Reliance on high- or low-quality firewood or crop residue (vs. charcoal) was associated with significantly higher odds of shortness of breath, difficulty breathing, chest pains, night phlegm, forgetfulness, dizziness, and dry irritated eyes. Use of high-quality firewood was associated with significantly lower odds of persistent phlegm. Cooks in rural areas (vs. urban areas) had significantly higher odds of experiencing shortness of breath, persistent cough, and phlegm, but significantly lower odds of phlegm, forgetfulness, and burns. With deforestation and population pressures increasing reliance on low-quality biomass fuels, prevalence of HAP-related cardiopulmonary and neurologic symptoms will likely increase among cooks. Short- to medium-term strategies are needed to secure access to high-quality biomass fuels given limited potential for scalable transitions to modern energy.