An Overview of Metal-Organic Framework Based Electrocatalysts: Design and Synthesis for Electrochemical Hydrogen Evolution, Oxygen Evolution, and Carbon Dioxide Reduction Reactions.

Due to the increasing global energy demands, scarce fossil fuel supplies, and environmental issues, the pursued goals of energy technologies are being sustainable, more efficient, accessible, and produce near zero greenhouse gas emissions. Electrochemical water splitting is considered as a highly viable and eco-friendly energy technology. Further, electrochemical carbon dioxide (CO2 ) reduction reaction (CO2 RR) is a cleaner strategy for CO2 utilization and conversion to stable energy (fuels). One of the critical issues in these cleaner technologies is the development of efficient and economical electrocatalyst. Among various materials, metal-organic frameworks (MOFs) are becoming increasingly popular because of their structural tunability, such as pre- and post- synthetic modifications, flexibility in ligand design and its functional groups, and incorporation of different metal nodes, that allows for the design of suitable MOFs with desired quality required for each process. In this review, the design of MOF was discussed for specific process together with different synthetic methods and their effects on the MOF properties. The MOFs as electrocatalysts were highlighted with their performances from the aspects of hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and electrochemical CO2 RR. Finally, the challenges and opportunities in this field are discussed.

Analyzing and Tuning the Chalcogen-Amine-Thiol Complexes for Tailoring of Chalcogenide Syntheses.

The amine-thiol solvent system has been used extensively to synthesize metal chalcogenide thin films and nanoparticles because of its ability to dissolve various metal and chalcogen precursors. While previous studies of this solvent system have focused on understanding the dissolution of metal precursors, here we provide an in-depth investigation of the dissolution of chalcogens, specifically Se and Te. Analytical techniques, including Raman, X-ray absorption, and NMR spectroscopy and high-resolution tandem mass spectrometry, were used to identify pathways for Se and Te dissolution in butylamine-ethanethiol and ethylenediamine-ethanethiol solutions. Se in monoamine-monothiol solutions was found to form ionic polyselenides free of thiol ligands, while in diamine-monothiol solutions, thiol coordination with polyselenides was predominately observed. When the relative concentration of thiol is increased to that of Se, the chain length of polyselenide species was observed to shorten. Analysis of Te dissolution in diamine-thiol solutions also suggested the formation of relatively unstable thiol-coordinated Te ions. This instability of Te ions was found to be reduced by codissolving Te with Se in diamine-thiol solutions. Analysis of the codissolved solutions revealed the presence of atomic interaction between Se and Te through the identification of Se-Te bonds. This new understanding then provided a new route to dissolve otherwise insoluble Te in butylamine-ethanethiol solutions by taking advantage of the Se2- nucleophile. Finally, the knowledge gained for chalcogen dissolutions in this solvent system allowed for controlled alloying of Se and Te in PbSenTe1-n material and also provided a general knob to alter various metal chalcogenide material syntheses.

'Oxidative stress'-A new target in the management of diabetes mellitus.

Diabetes mellitus (DM) is a chronic condition that poses a mammoth challenge for the healthcare system in developing as well as developed nations. Diabetes mellitus is associated with damage to the vasculature which leads to microvascular and macrovascular complications. Oxidative stress is a consequence of glucotoxicity and lipotoxicity, which are associated with diabetes. Glucotoxicity and lipotoxicity play a part in the pathogenesis of ß-cell dysfunction. The hyperglycemic state in DM leads to oxidative stress which further hampers insulin secretion. In diabetes, the biological antioxidants also get depleted along with a reduction in glutathione (GSH), an increase in the oxidized glutathione (GSSG)/GSH ratio, and a depletion of non-enzymatic antioxidants. This results in the formation of a viscous circle of hyperglycemia leading to increased oxidative stress that further hampers insulin secretion which in turn results in hyperglycemia. Antioxidants are efficacious in reducing diabetic complications. The antioxidants produced biologically fall short, hence external supplements are required. In this review, the authors have discussed the relationship between oxidative stress in DM and the advantages of antioxidant supplements in controlling blood glucose levels and also in deaccelerating the complications related to DM.

Molecular Precursor Approach to Sulfur-Free CuInSe2: Replacing Thiol Coordination in Soluble Metal Complexes.

Solution-processed CuInSe2 films have generally relied on sulfide or sulfoselenide precursor films that, during the grain growth process, hamper the growth of thicker films and lead to the formation of a fine-grain layer. However, recent research has indicated that sulfur reduction in the precursor film modifies the grain growth mechanism and may enable the fabrication of thicker absorbers that are free of any fine-grain layer. In this work, we pursue direct solution deposition of sulfur-free CuInSe2 films from the molecular precursor approach. To this end, we tune the amine-thiol reactive solvent system and study the changes to the resulting soluble complexes through a combination of analytical techniques. We show that by reactively dissolving indium(III) selenide and selenium in solutions of n-butylamine and 1,2-ethanedithiol, a metal thiolate species is formed, and that this metal thiolate can be modified by isolation from the thiol-containing solvent via precipitation. As the quantity of selenium in the ink increases, the thiol content in the complex decreases, eventually producing soluble [InSex]- species. Extending this method to be used with copper selenide as a copper source, molecular precursor inks can be made for solution-processed, sulfur-free CuInSe2 films. We then show that these CuInSe2 precursor films can be fully coarsened without a fine-grain layer formation, even at the desired thicknesses of 2 µm and greater.

A review on biopolymer-derived electrospun nanofibers for biomedical and antiviral applications.

The unique aspects of polymer-derived nanofibers provide significant potential in the areas of biomedical and health care applications. Much research has demonstrated several plausible nanofibers to overcome the modern-day challenges in the field of medical and healthcare. The present review highlights the electrochemical-based nanofibre technologies, special properties of such nanofibres, fabrication strategies (by the electrospinning technique), and their usage in biomedical and healthcare applications. Also, it summarizes the current research on nanofibers as pharmaceutical agents and sustained drug release, tissue-engineered scaffolds, wound healing dressing materials, and antiviral healthcare units like masks, respirators, and personal protective equipment (PPE kits). Attention is given to exclusive sorts of ultrafine fibers (e.g. mesoporous, hollow, core-shell nanofibers) fabricated from various biopolymers and their achievable biomedical applications.

Solution Phase Growth and Ion Exchange in Microassemblies of Lead Chalcogenide Nanoparticles.

We demonstrate the synthesis of micron-sized assemblies of lead chalcogenide nanoparticles with controlled morphology, crystallinity, and composition through a facile room-temperature solution phase reaction. The amine-thiol solvent system enables this synthesis with a unique oriented attachment growth mechanism of nanoparticles occurring on the time scale of the reaction itself, forming single-crystalline microcubes of PbS, PbSe, and PbTe materials. Increasing the rate of reaction by changing reaction parameters further allows disturbing the oriented attachment mechanism, which results in polycrystalline microassemblies with uniform spherical morphologies. Along with polycrystallinity, due to the differences in reactivities of each chalcogen in the solution, a different extent of hollow-core nature is observed in these microparticles. Similar to morphologies, the composition of such microparticles can be altered through very simplistic room-temperature solution phase coprecipitation, as well as ion-exchange reactions. While coprecipitation reactions are successful in synthesizing core-shell microstructures of PbSe-PbTe materials, the use of solution phase ion-exchange reaction allows for the exchange of not only Te with Se but also Ag with Pb inside the core of the PbTe microparticles. Despite exchanging one Pb with two Ag cations, the hollow-core nature of particles aids in the retention of the original uniform microparticle morphology.

Comparison of efficacy and safety of topical 1% nadifloxacin and tretinoin 0.025% combination therapy with 1% clindamycin and tretinoin 0.025% combination therapy in patients of mild-to-moderate acne.

BACKGROUND: Topical retinoids in combination with antimicrobials have been proven to reduce acne lesions faster and to a greater degree than antimicrobial therapy alone . AIMS AND OBJECTIVES: To compare the efficacy and safety of topical combination of 1% Nadifloxacin [NAD] and 0.025% Tretinoin [Tr] with 1% Clindamycin [CLN] and 0.025% Tr in patients of mild to moderate acne vulgaris of the face. MATERIAL AND METHODS: There were two groups (40 patients in each group): Group A received (NAD+Tr) combination therapy and group B received (CLN+Tr) combination therapy. Efficacy was assessed by any reduction in the mean number of inflammatory lesions(IL), non-inflammatory lesions(NIL) and/or total lesions(TL) as well as by using Evaluator's Global Severity Scale (EGSS) of acne and safety was assessed by adverse effects of study medications at 0, 6 and at 12 weeks follow-up. RESULTS: Both the study groups showed statistically significant intragroup reduction in NIL, IL and TL after 12 weeks of therapy. There was no statistically significant reduction at the end of 6 weeks of therapy in both the groups. At the end of 12 weeks of therapy there was a statistically significant reduction in IL, NIL and TL in group A. There was no statistically significant difference in the occurrence of adverse effects in both the groups. CONCLUSION: Overall the study proved better efficacy of NAD+Tr compared to CLN+Tr. Medications of both the groups were safe and well tolerated.