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1.
Nature ; 629(8013): 886-892, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38720071

RESUMO

Cobalamin (vitamin B12, herein referred to as B12) is an essential cofactor for most marine prokaryotes and eukaryotes1,2. Synthesized by a limited number of prokaryotes, its scarcity affects microbial interactions and community dynamics2-4. Here we show that two bacterial B12 auxotrophs can salvage different B12 building blocks and cooperate to synthesize B12. A Colwellia sp. synthesizes and releases the activated lower ligand α-ribazole, which is used by another B12 auxotroph, a Roseovarius sp., to produce the corrin ring and synthesize B12. Release of B12 by Roseovarius sp. happens only in co-culture with Colwellia sp. and only coincidently with the induction of a prophage encoded in Roseovarius sp. Subsequent growth of Colwellia sp. in these conditions may be due to the provision of B12 by lysed cells of Roseovarius sp. Further evidence is required to support a causative role for prophage induction in the release of B12. These complex microbial interactions of ligand cross-feeding and joint B12 biosynthesis seem to be widespread in marine pelagic ecosystems. In the western and northern tropical Atlantic Ocean, bacteria predicted to be capable of salvaging cobinamide and synthesizing only the activated lower ligand outnumber B12 producers. These findings add new players to our understanding of B12 supply to auxotrophic microorganisms in the ocean and possibly in other ecosystems.


Assuntos
Prófagos , Vitamina B 12 , Vitamina B 12/metabolismo , Vitamina B 12/biossíntese , Ligantes , Prófagos/metabolismo , Corrinoides/metabolismo , Oceano Atlântico , Interações Microbianas , Técnicas de Cocultura , Actinobacteria/metabolismo
2.
Heliyon ; 10(7): e28290, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38689953

RESUMO

In this work there was investigated the synergistic effect of the nanomaterials-the Montmorillonite (MMT) and the vanadium pentoxide (V2O5) on the polyvinyl alcohol (PVA)/starch composite. The composite films were prepared by the solvent casting method. The characterization of the composites showed that the addition of the MMT and the V2O5 to PVA/starch composite decreased the water solubility and water absorption capacity of the film. Both of the reinforcement materials enriched values of thermal conductivity and thermal stability of the composite. The TG/DTA and universal testing machine (UTM) analysis exhibited that MMT and V2O5 augmented the thermal robustness and tensile strength of composites and decreased the strain to break. It was also observed that greater MMT concentration accelerates mechanical strength deterioration of the film owing to agglomeration. The scanning electron microscopy (SEM) analysis reflected great change in the surface morphology of the films in the presence and absence of MMT and V2O5. This was due to the interaction amid constituents of the composite. The chemical interaction between the PVA, Starch, MMT and the V2O5 was also established via Fourier-transform infrared spectroscopy (FTIR) analysis, which revealed fluctuations in the absorbance position and intensity of the PVA/Starch. Antimicrobial activities against seven different cultures of bacteria (both-gram positive and -negative) and one fungus (Candida albicans), exposed that antimicrobial performance of the PVA amplified upon addition of the starch, MMT and V2O5, making these composites prospective candidates for the biodegradable packaging materials.

3.
ACS Omega ; 9(12): 13917-13927, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38559970

RESUMO

In the pursuit of finding efficient D-π-A organic dyes as photosensitizers for dye-sensitized solar cells (DSSCs), first-principles calculations of guanidine-based dyes [A1-A18] were executed using density functional theory (DFT). The various electronic and optical properties of guanidine-based organic dyes with different D-π-A structural modifications were investigated. The structural modification of guanidine-based dyes largely affects the properties of molecules, such as excitation energies, the oscillator strength dipole moment, the transition dipole moment, and light-harvesting efficiencies. The energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) is responsible for the reduction and injection of electrons. Modification of the guanidine subunit by different structural modifications gave a range of HOMO-LUMO energy gaps. Chemical and optical characteristics of the dyes indicated prominent charge transfer and light-harvesting efficiencies. The wide electronic absorption spectra of these guanidine-based dyes computed by TD-DFT-B3LYP with 6-31G, 6-311G, and cc-PVDZ basis sets have been observed in the visible region of spectra due to the presence of chromophore groups of dye molecules. Better anchorage of dyes to the surface of TiO2 semiconductors helps in charge-transfer phenomena, and the results suggested that -COOH, -CN, and -NO2 proved to be proficient anchoring groups, making dyes very encouraging candidates for DSSCs. Molecular electrostatic potential explained the electrostatic potential of organic dyes, and IR spectrum and conformational analyses ensured the suitability of organic dyes for the fabrication of DSSCs.

4.
Heliyon ; 10(1): e24268, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38234878

RESUMO

The escalation of healthcare spending in many nations, particularly in emerging countries such as Bangladesh, may be largely attributed to the growing demand for healthcare services. Evidently, there has been a significant expansion in the public funding allocated to the health sector in Bangladesh, intending to enhance health outcomes. Therefore, the purpose of this study was to examine the impact of healthcare expenditure on health outcomes, specifically focusing on the reduction in different mortality rates and the transmission of various infectious diseases. A total of 30 years of data (1990-2019) on the health sector of Bangladesh were collected from different national and international sources. The Vector Autoregression with Exogenous Variables (VARX) model was employed to determine the effects of healthcare expenditure on health outcomes. Results revealed that the per capita health expenditure and the number of doctors showed a significant positive impact on life expectancy and maternal and child health. Also, the government's annual budget on the health sector and number of doctors had a significant positive impact on lowering deaths by Diphtheria, Cholera, Tuberculosis, and Malaria diseases. In order to develop a sustainable healthcare system within the nation, it is imperative for the government to prioritize the allocation of sufficient and effective healthcare funding to cater to the needs of the populace.

5.
ISME J ; 17(6): 836-845, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36914732

RESUMO

Vitamin B12 (cobalamin, herein B12) is an essential cofactor involved in amino acid synthesis and carbon resupply to the TCA cycle for most prokaryotes, eukaryotic microorganisms, and animals. Despite being required by most, B12 is produced by only a minor fraction of prokaryotes and therefore leads to complex interaction between prototrophs and auxotrophs. However, it is unknown how B12 is provided by prototrophs to auxotrophs. In this study, 33 B12 prototrophic alphaproteobacterial strains were grown in co-culture with Thalassiosira pseudonana, a B12 auxotrophic diatom, to determine the bacterial ability to support the growth of the diatom by sharing B12. Among these strains, 18 were identified to share B12 with the diatom, while nine were identified to retain B12 and not support growth of the diatom. The other bacteria either shared B12 with the diatom only with the addition of substrate or inhibited the growth of the diatom. Extracellular B12 measurements of B12-provider and B12-retainer strains confirmed that the cofactor could only be detected in the environment of the tested B12-provider strains. Intracellular B12 was measured by LC-MS and showed that the concentrations of the different B12-provider as well as B12-retainer strains differed substantially. Although B12 is essential for the vast majority of microorganisms, mechanisms that export this essential cofactor are still unknown. Our results suggest that a large proportion of bacteria that can synthesise B12 de novo cannot share the cofactor with their environment.


Assuntos
Diatomáceas , Vitamina B 12 , Vitamina B 12/metabolismo , Bactérias/genética , Bactérias/metabolismo , Diatomáceas/metabolismo , Vitaminas/metabolismo
6.
J Phycol ; 59(2): 309-322, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36471567

RESUMO

Interactions between marine diatoms and bacteria have been studied for decades. However, the visualization of physical interactions between these diatoms and their colonizers is still limited. To enhance our understanding of these specific interactions, a new Thalassiosira rotula isolate from the North Sea (strain 8673) was characterized by scanning electron microscopy and confocal laser scanning microscopy (CLSM) after staining with fluorescently labeled lectins targeting specific glycoconjugates. To investigate defined interactions of this strain with bacteria the new strain was made axenic and co-cultivated with a natural bacterial community and in two- or three-partner consortia with different bacteria of the Roseobacter group, Gammaproteobacteria and Bacteroidetes. The CLSM analysis of the consortia identified six out of 78 different lectins as very suitable to characterize glycoconjugates of T. rotula. The resulting images show that fucose-containing threads were the dominant glycoconjugates secreted by the T. rotula cells but chitin and to a lesser extent other glycoconjugates were also identified. Bacteria attached predominantly to the fucose glycoconjugates. The colonizing bacteria showed various attachment patterns such as adhering to the diatom threads in aggregates only or attaching to both the surfaces and the threads of the diatom. Interestingly the colonization patterns of single bacteria differed strikingly from those of bacterial co-cultures, indicating that interactions between two bacterial species impacted the colonization of the diatom. Our observations help to better understand physical interactions and specific colonization patterns of distinct bacterial mono- and co-cultures with an abundant diatom of costal seas.


Assuntos
Diatomáceas , Diatomáceas/metabolismo , Fucose/metabolismo , Bactérias/metabolismo , Ecossistema , Glicoconjugados/metabolismo , Lectinas/metabolismo
7.
Front Nutr ; 10: 1271931, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38249611

RESUMO

Background: Anemia poses a significant public health problem, affecting 1.6 billion people and contributing to the loss of 68.4 million disability-adjusted life years. We assessed the impact of a market-based home fortification program with micronutrient powder (MNP) called Pushtikona-5 implemented by Bangladesh Rural Advancement Committee (BRAC) on the prevalence of anemia among children aged 6-59 months in Bangladesh. Methods: We used a modified stepped wedged design and conducted three baseline, two midline, and three endline surveys to evaluate the Pushtikona-5 program implemented through three BRAC program platforms. We interviewed children's caregivers, and collected finger-prick blood samples from children to measure hemoglobin concentration. We also collected data on coverage of Pushtikona-5 and infant and young child feeding (IYCF) practices. We performed bivariate and multivariable analysis and calculated adjusted risk ratios (ARRs) to assess the effect of program outcomes. Results: A total of 16,936 households were surveyed. The prevalence of anemia was 46.6% at baseline, dropping to 32.1% at midline and 31.2% at endline. These represented adjusted relative reductions of 34% at midline (RR 0.66, 95%CI 0.62 to 0.71, value of p <0.001) and 32% at endline (RR 0.68, 95%CI 0.64 to 0.71, value of p <0.001) relative to baseline. Regarding MNP coverage, at baseline, 43.5% of caregivers surveyed had heard about MNP; 24.3% of children had ever consumed food with MNP, and only 1.8% had consumed three or more sachets in the 7 days preceding the survey. These increased to 63.0, 36.9, and 4.6%, respectively, at midline and 90.6, 68.9, and 11.5%, respectively, at endline. Conclusion: These results show evidence of a reduction in the prevalence of anemia and an improvement in coverage. This study provides important evidence of the feasibility and potential for impact of linking market-based MNP distribution with IYCF promotion through community level health workers.

8.
ISME J ; 16(11): 2599-2609, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35963899

RESUMO

Biotin (vitamin B7) is involved in a wide range of essential biochemical reactions and a crucial micronutrient that is vital for many pro- and eukaryotic organisms. The few biotin measurements in the world's oceans show that availability is subject to strong fluctuations. Numerous marine microorganisms exhibit biotin auxotrophy and therefore rely on supply by other organisms. Desthiobiotin is the primary precursor of biotin and has recently been detected at concentrations similar to biotin in seawater. The last enzymatic reaction in the biotin biosynthetic pathway converts desthiobiotin to biotin via the biotin synthase (BioB). The role of desthiobiotin as a precursor of biotin synthesis in microbial systems, however, is largely unknown. Here we demonstrate experimentally that bacteria can overcome biotin auxotrophy if they retain the bioB gene and desthiobiotin is available. A genomic search of 1068 bacteria predicts that the biotin biosynthetic potential varies greatly among different phylogenetic groups and that 20% encode solely bioB and thus can potentially overcome biotin auxotrophy. Many Actino- and Alphaproteobacteria cannot synthesize biotin de novo, but some possess solely bioB, whereas the vast majority of Gammaproteobacteria and Flavobacteriia exhibit the last four crucial biotin synthesis genes. We detected high intra- and extracellular concentrations of the precursor relative to biotin in the prototrophic bacterium, Vibrio campbellii, with extracellular desthiobiotin reaching up to 1.09 ± 0.15*106 molecules per cell during exponential growth. Our results provide evidence for the ecological role of desthiobiotin as an escape route to overcome biotin auxotrophy for bacteria in the ocean and presumably in other ecosystems.


Assuntos
Biotina , Ecossistema , Bactérias/genética , Bactérias/metabolismo , Biotina/análogos & derivados , Biotina/metabolismo , Micronutrientes , Filogenia , Vitaminas
9.
J Colloid Interface Sci ; 625: 83-99, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35714411

RESUMO

Nitrogen reduction to ammonia is vital for chemical industries and renewable clean energy. Denying the harsh reaction conditions adopted in the Haber-Bosch process and stimulation research for ammonia production through sustainable technologies is a smart approach. Hitherto, photocatalyst acquiring the potential to attain high nitrogen reduction reaction (NRR) efficiency is a challenging task. Here, this study demonstrated cobalt titanate (CoTiO3) rods (p-type) straddled with two-dimensional (2D) sheets of nitrogen-doped reduced graphene oxide (N-rGO, n-type) via, reflux method; realizing the advantages of dissimilar dimensionalities and strong interfacial junction coupling for efficient NRR under visible light irradiation. The successful interface junction establishment between CoTiO3 and N-rGO has been witnessed from Raman, x-ray photoelectron spectroscopy (XPS), and Mott-Schottky analysis. Moreover, a well-defined type-II band structure is capable to curl the charge anti-recombination process; reflected in upgraded photo-catalytic/electrocatalytic upshots. The CoTiO3 modified with an optimized concentration of N-rGO exhibits high stability with an improved photocatalytic (1722.22 µmolL-1h-1) and photo-electrocatalytic (16.8 µg cm-1h-1) nitrogen reduction to ammonia production; multiple times higher than counterparts. This improved photo-activity of CoTiO3/N-rGO junction hybrid stems from the built-in electric field existing across the dissimilar junction interface, triggering charge transfer channels for reduction reaction in mild reaction conditions. The result of these materials might strategies the way for future development of new functionalities bearing highly active catalyst materials for sustainable energy-related conversion.

10.
Curr Cardiol Rep ; 24(6): 659-665, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35380385

RESUMO

PURPOSE OF THIS REVIEW: We discuss the role of observational studies and cardiac registries during the COVID-19 pandemic. We focus on published cardiac registries and highlight contributions to the field that have had clinical implications. RECENT FINDINGS: We included observational studies of COVID-19 patients published in peer-reviewed medical journals with defined inclusion and exclusion criteria, defined study design, and primary outcomes. A PubMed and MEDLINE literature review results in 437 articles, of which 52 include patients with COVID-19 with cardiac endpoints. From July 2020 to December 2021, the average time from last data collected to publication was 8.9 ± 4.1 months, with an increasing trend over time (R = 0.9444, p < 0.0001). Of the 52 articles that met our inclusion criteria, we summarize main findings of 4 manuscripts on stroke, 14 on acute coronary syndrome, 4 on cardiac arrest, 7 on heart failure, 7 on venous thromboembolism, 5 on dysrhythmia, and 11 on different populations at risk for cardiovascular. Registries are cost effective, not disruptive to essential health services, and can be rapidly disseminated with short intervals between last data point collected and publication. In less than 2 years, cardiac registries have filled important gaps in knowledge and informed the care of COVID-19 patients with cardiovascular conditions.


Assuntos
COVID-19 , Insuficiência Cardíaca , COVID-19/epidemiologia , Humanos , Pandemias , Sistema de Registros , SARS-CoV-2
11.
Inorg Chem ; 61(1): 131-140, 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-34936349

RESUMO

The nitrogen reduction reaction is of great scientific significance as a hydrogen fuel carrier as well as a source of value-added products; in context to this, photoelectrochemical (PEC) nitrogen fixation emerges as an effective and environmentally benign strategy to meet the need. Hence, the current work reports an effective catalytic system containing a low-cost iron boride-based cocatalyst onto the CeO2 nanosheet matrix for photoelectrochemical nitrogen reduction reaction. The harmonized electronic property and the ensemble effect of phosphorus and boron in FeB/P with unsaturated metal sites make it a site-selective cocatalyst for nitrogen adsorption and its polarization. Furthermore, the low Fermi level of iron borophosphide enhances the trapping of photogenerated electrons from CeO2 and productively provides it to the adsorbed nitrogen species. The observed peculiar photocurrent behavior confirms the interaction of photogenerated electrons with adsorbed nitrogen species and its subsequent reduction by the surrounding protonic environment. The optimized CeO2-FeB/P photoelectrocatalyst exhibited an excellent NH3 yield velocity, i.e., 9.54 µg/h/cm2 at -0.12 V vs RHE with a solar-to-chemical conversion efficiency of 0.046% under ambient conditions. The same catalyst is also very active under near-zero biasing conditions and possesses impressive durability even after multiple uses. This work might strategically direct a promising way for the exploration of new photoelectrocatalytic systems for effective PEC-nitrogen reduction reaction.

12.
J Adv Vet Anim Res ; 9(4): 712-719, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36714510

RESUMO

Objectives: This study aimed to assess the influence of feeding fresh lemongrass (Cymbopogon citratus) or spearmint (Mentha spicata) and their combination on performance, serum metabolites, liver enzymes, and meat quality in broilers. Materials and Methods: A total of 168 day-old Indian River chicks were arbitrarily offered four experimental rations: (i) control ration (CT-R): corn-soya-based ration, (ii) lemongrass ration (LG-R): CT-R + 1.0% DM of lemongrass; (iii) spearmint ration (SM-R): CT-R + 1.0% DM of spearmint; and (iv) lemongrass-spearmint ration (LS-R): CT-R + 0.5% DM from both lemongrass and spearmint. Each ration was given to 42 birds for a duration of 35 days, with 3 replications and 14 birds each. Results: Elevated body weight gain was observed in LG-R (1,502 gm), LS-R (1,492 gm), and SM-R (1,474 gm) compared to CT-R (1,451 gm) (p = 0.078). Herbal rations successfully reduced almost 3%-5% of serum and meat total cholesterol concentrations compared to CT-R. Compared to CT-R, the highest zinc and iron concentrations of serum and meat were measured in LG-R and SM-R, respectively, while both minerals of serum and meat were observed to be better in LS-R (p < 0.05). Herbal rations significantly improved serum liver enzyme activity and ameliorated the red color of breast and thigh meat but failed to improve the lightness and yellowness of both types of meat compared to CT-R. Conclusions: LG-R, SM-R, and LS-R improved bird performance, liver health, and meat color, and lowered serum and meat cholesterol levels. But among them, LS-R efficaciously increased the serum and meat zinc and iron concentrations.

13.
Food Policy ; 104: 102127, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34720342

RESUMO

Micronutrient deficiency is a pertinent global challenge that affects billions of people and has deleterious health effects. Large-scale food fortification (LSFF) is a cost- effective way to tackle micronutrient deficiency and improve health outcomes, particularly in low- and middle-income countries (LMICs). However, the success of LSFF in LMICs is often hampered by limited compliance with fortification mandates by the private sector, who supply fortified foods. In this paper, we use a case study of the edible oil produced in Bangladesh to analyze the factors facilitating and impeding this compliance by for-profit actors. We identified four bottlenecks that disincentivize private sector actors' decision to comply. First, fortified and non-fortified products co-exist in the market, disincentivizing producers to invest in fortification. Second, the lack of traceability reduces the risk for large-scale producers' non-compliance with the regulation. Third, small-scale producers face economic pressures that prevent them from adequately fortifying oil products. Lastly, law enforcement is currently inconsistent, allowing the supply of under-fortified oil in the market. Given the evidence, we recommend to strengthen the control of bulk item fortification through more frequent and rigorous surveillance at the production level. This will ensure that resource constrained consumers who also have the greatest potential to benefit from added nutrients, remain able to access affordable and nutrient-enriched food.

14.
Pediatr Infect Dis J ; 40(9S): S79-S90, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34448747

RESUMO

BACKGROUND: Pneumonia remains the leading infectious cause of death among children <5 years, but its cause in most children is unknown. We estimated etiology for each child in 2 Bangladesh sites that represent rural and urban South Asian settings with moderate child mortality. METHODS: As part of the Pneumonia Etiology Research for Child Health study, we enrolled children 1-59 months of age with World Health Organization-defined severe and very severe pneumonia, plus age-frequency-matched controls, in Matlab and Dhaka, Bangladesh. We applied microbiologic methods to nasopharyngeal/oropharyngeal swabs, blood, induced sputum, gastric and lung aspirates. Etiology was estimated using Bayesian methods that integrated case and control data and accounted for imperfect sensitivity and specificity of the measurements. RESULTS: We enrolled 525 cases and 772 controls over 24 months. Of the cases, 9.1% had very severe pneumonia and 42.0% (N = 219) had infiltrates on chest radiograph. Three cases (1.5%) had positive blood cultures (2 Salmonella typhi, 1 Escherichia coli and Klebsiella pneumoniae). All 4 lung aspirates were negative. The etiology among chest radiograph-positive cases was predominantly viral [77.7%, 95% credible interval (CrI): 65.3-88.6], primarily respiratory syncytial virus (31.2%, 95% CrI: 24.7-39.3). Influenza virus had very low estimated etiology (0.6%, 95% CrI: 0.0-2.3). Mycobacterium tuberculosis (3.6%, 95% CrI: 0.5-11.0), Enterobacteriaceae (3.0%, 95% CrI: 0.5-10.0) and Streptococcus pneumoniae (1.8%, 95% CrI: 0.0-5.9) were the only nonviral pathogens in the top 10 etiologies. CONCLUSIONS: Childhood severe and very severe pneumonia in young children in Bangladesh is predominantly viral, notably respiratory syncytial virus.


Assuntos
Pneumonia/etiologia , Bangladesh/epidemiologia , Teorema de Bayes , Estudos de Casos e Controles , Saúde da Criança , Pré-Escolar , Países em Desenvolvimento , Feminino , Hospitalização , Humanos , Lactente , Modelos Logísticos , Masculino , Gravidade do Paciente , Pneumonia/diagnóstico , Pneumonia/epidemiologia , Pneumonia/prevenção & controle , Fatores de Risco , Saúde da População Rural/estatística & dados numéricos , Saúde da População Urbana/estatística & dados numéricos
15.
Nanoscale ; 13(22): 9908-9944, 2021 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-34038496

RESUMO

Fossil fuels as a double-edged sword are essential to daily life. However, the depletion of fossil fuel reservoirs has increased the search for alternative renewable energy sources to procure a more sustainable society. Accordingly, energy production through water splitting, CO2 reduction and N2 reduction via photocatalytic and electrocatalytic pathways is being contemplated as a greener methodology with zero environmental pollution. Owing to their atomic-level thickness, two-dimensional (2D) semiconductor catalysts have triggered the reawakening of interest in the field of energy and environmental applications. Among them, following the unconventional properties of graphene, 2D MoS2 has been widely investigated due to its outstanding optical and electronic properties. However, the photo/electrocatalytic performance of 2D-MoS2 is still unsatisfactory due to its low charge carrier density. Recently, the development of 2D/2D heterojunctions has evoked interdisciplinary research fascination in the scientific community, which can mitigate the shortcomings associated with 2D-MoS2. Following the recent research trends, the present review covers the recent findings and key aspects on the synthetic methods, fundamental properties and practical applications of semiconducting 2D-MoS2 and its heterostructures with other 2D materials such as g-C3N4, graphene, CdS, TiO2, MXene, black phosphorous, and boron nitride. Besides, this review details the viable application of these materials in the area of hydrogen energy production via the H2O splitting reaction, N2 fixation to NH3 formation and CO2 reduction to different value-added hydrocarbons and alcohol products through both photocatalysis and electrocatalysis. The crucial role of the interface together with the charge separation principle between two individual 2D structures towards achieving satisfactory activity for various applications is presented. Overall, the current studies provide a snapshot of the recent breakthroughs in the development of various 2D/2D-based catalysts in the field of energy production, delivering opportunities for future research.

16.
Heliyon ; 7(2): e06148, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33644454

RESUMO

Natural resources are non-renewable and facing a regular depletion due to their immense use which demands new and additional material's reserves, recycling technologies and materials with no or less bad environmental effects. Reuse of waste materials will be rewarding technically, economically and environmentally. Here, we report the incorporation of industrial ceramic wastes in polymer matrix as composite materials to investigate their potentials for various applications. Ceramic wastes were collected from the premises of ceramic producing industries located at Peshawar (Pakistan). The composites of ceramic particles and polyaniline (PANI) were produced via in-situ free polymerization technique. SEM and FT-IR analysis confirmed composite formation. Thermal, dielectric and mechanical properties of the prepared materials were studied. It was found that both the constituent materials (ceramic and polymer) have a synergistic effect on each other. At one hand, ceramic wastes support and enhance the thermal and mechanical properties of the polymer in composites and the polymer in turn beautify the wastes with good dielectric and electrical properties. Based on their properties, the low cost and environmentally friendly novel composites could be used for various applications such as semi-conductors, capacitors and microwave devices.

17.
Public Health Nutr ; 24(S1): s48-s58, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-32131922

RESUMO

OBJECTIVE: We assessed the role of home visits by Shasthya Shebika (SS) - female volunteer community health workers (CHWs) - in improving the distribution of micronutrient powder (MNP), and explored the independent effects of caregiver-provider interaction on coverage variables. DESIGN: We used data from three cross-sectional surveys undertaken at baseline (n 1927), midline (n 1924) and endline (n 1540) as part of an evaluation of a home fortification programme. We defined an exposure group as one that had at least one SS visit to the caregiver's household in the 12 months preceding the survey considering three outcome variables - message (ever heard), contact (ever used) and effective coverage (regular used) of MNP. We performed multiple logistic regressions to explore the determinants of coverage, employed an 'interaction term' and calculated an odds ratio (OR) to assess the modifying effect of SS's home visits on coverage. SETTINGS: Sixty-eight sub-districts from ten districts of Bangladesh. PARTICIPANTS: Children aged 6-59 months and their caregivers. RESULTS: A home visit from an SS positively impacts message coverage at both midline (ratio of OR 1·70; 95 % CI 1·25, 2·32; P < 0·01) and endline (ratio of OR 3·58; 95 % CI 2·22, 5·78; P < 0·001), and contact coverage both at midline (ratio of OR 1·48; 95 % CI 1·06, 2·07; P = 0·021) and endline (ratio of OR 1·74; 95 % CI 1·23, 2·47; P = 0·002). There was no significant effect of a SS's home visit on effective coverage. CONCLUSIONS: The households visited by BRAC's volunteer CHWs have better message and contact coverage among the children aged 6-59 months.


Assuntos
Visita Domiciliar , Micronutrientes , Bangladesh , Criança , Agentes Comunitários de Saúde , Estudos Transversais , Feminino , Humanos , Pós , Voluntários
18.
Front Microbiol ; 11: 570855, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33281765

RESUMO

The Sundarbans forest in Bangladesh is the world's largest mangrove. It is a unique ecosystem where living organisms face extreme challenges to compete for survival. Such competition results in the production of bioactive molecules which are useful for agriculture and human health. In this study, eighty fungal endophytes from nine mangrove plants growing in a region, as yet unexplored, of the Sundarbans were isolated by surface sterilisation and pure culture techniques. Among the eighty isolates subjected to a preliminary antimicrobial screening using an agar plug diffusion assay, only fifteen showed some promising activity. These were subsequently identified by polymerase chain reaction of their ITS gene. Extracts prepared from the identified isolates were screened for antimicrobial, antioxidant, cytotoxic and α-glucosidase inhibitory activities. Their total polyphenol and flavonoid content and their FRAP value were also determined. All endophytes are reported for the first time in the plants under investigation.

20.
Inorg Chem ; 59(6): 3856-3873, 2020 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-32141738

RESUMO

For better exciton separation and high catalytic activity, the most trailblazing stratagem is to construct defect engineered low-dimensional p-n heterojunction framed photocatalytic systems. In this context, we have developed a rod-sheet (1D-2D) p-n heterojunction of MCeO2-BiFeO3 by a simple hydrothermal method and scrutinized its photocatalytic performance toward N2 fixation and phenol/Cr(VI) detoxification. The intimate contact between MCeO2 and BiFeO3 in the junction material is well established via X-ray diffraction (XRD), UV-vis diffuse reflectance spectrosopy (DRS), transmission electron microscopy (TEM), and photoelectrochemical studies. Further, scanning electron microscopy (SEM) and TEM pictures clearly support the decoration of MCeO2 nanorods over BiFeO3 sheets and also depict the junction boundary. Additionally, photoluminescence (PL), electron paramagnetic resonance (EPR), X-ray photoelectron spectroscopy (XPS), and Raman measurements give solid evidence toward the presence of an oxygen vacancy. Moreover, the Mott-Schottky result indicates a feasible band edge potential favoring the p-n heterojunction with a built-in electric field between BiFeO3 and MCeO2 favoring a double charge dynamic. The MCeO2-BFO p-n junction displays a notable catalytic activity, i.e., 98.2% Cr(VI) reduction and 85% phenol photo-oxidation, and produces 117.77 µmol h-1 g-1 of ammonia under light irradiation. Electrochemical analysis suggests a four-electron/five proton-coupled N2 photoreduction pathway. The designed oxygen vacancy oriented p-n heterojunction suffering double charge migration shows significant catalytic performance due to effective electron-hole separation as justified via PL, electrochemical impedance spectra (EIS), and Bode phase analysis.

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