Protein aggregation, due to the imbalance in the concentration of Cu
2+
and Zn
2+
ions is found to be allied with various physiological disorders. Copper is known to promote the oxidative damage of ...β/γ-crystallins in aged eye lens and causes their aggregation leading to cataract. Therefore, synthesis of a small-molecule ‘chelator’ for Cu
2+
with complementary antioxidant effect will find potential applications against aggregation of β/γ-crystallins. In this paper, we have reported the synthesis of different Schiff bases and studied their Cu
2+
complexation ability (using UV–Vis, FT-IR and ESI-MS) and antioxidant activity. Further based on their copper complexation efficiency, Schiff bases were used to inhibit Cu
2+
-mediated aggregation of recombinant human γD-crystallin (HGD) and β/γ-crystallins (isolated from cataractous human eye lens). Among these synthesized molecules, compound
8
at a concentration of 100 μM had shown ~95% inhibition of copper (100 μM)-induced aggregation. Compound
8
also showed a positive cooperative effect at a concentration of 5–15 μM on the inhibitory activity of human αA-crystallin (HAA) during Cu
2+
-induced aggregation of HGD. It eventually inhibited the aggregation process by additional ~20%. However, ~50% inhibition of copper-mediated aggregation of β/γ-crystallins (isolated from cataractous human eye lens) was recorded by compound
8
(100 μM). Although the reductive aminated products of the imines showed better antioxidant activity due to their lower copper complexing ability, they were found to be non-effective against Cu
2+
-mediated aggregation of HGD.
Graphical Abstract
The efficacy and safety of a selective NK(1) antagonist, L-759274, was investigated in outpatients with diagnosis of major depressive disorder with melancholic features, following evidence obtained ...with the novel compound aprepitant that Substance P (NK(1)) antagonists may provide a unique mechanism of antidepressant activity. A randomized, double-blind placebo-controlled study was carried out. Patients, male or female, aged 18-60, scoring >/=25 points on total of first 17 items of 21-item Hamilton Depression Scale (HAMD), and scoring >/=4 (moderately ill) on Clinical Global Impressions-Severity Scale were randomized to oral L-759274 40 mg daily (n=66) or placebo (n=62) for 6 weeks. For patients receiving L-759274, improvement (mean decrease from baseline) in HAMD-17 total score was 10.7 points, compared with a mean 7.8 point improvement in patients receiving placebo (p<0.009). Mean scores for item 1 of HAMD-17 (depressed mood) also improved to a greater extent in the active group compared with the placebo group (0.3 points, p<0.058). Compared with placebo, mean scores on Clinical Global Impressions-Improvement Scale improved significantly by the end of the trial (p=0.009). L-759274 was generally safe and well-tolerated. The incidence of sexual side effects was on par with that observed in patients receiving placebo, and the incidences of gastrointestinal effects were low. Antidepressant actions have now been observed with two different highly selective NK(1) antagonists (aprepitant and L-759274). NK(1) antagonism is a replicated and generally well-tolerated antidepressant mechanism.
The present work reports on the fabrication of a lightweight microwave absorber comprising MnCo
O
prepared from the urea complex of manganese (Mn)/cobalt (Co) and nitrogen-doped reduced graphite ...oxide (NRGO) by facile hydrothermal method followed by annealing process and characterized. The phase analysis, compositional, morphological, magnetic, and conductivity measurements indicated dispersion of paramagnetic MnCo
O
spherical particles on the surface of NRGO. Our findings also showed that Mn, Co-urea complex, and GO in the weight ratio of 1:4 (NGMC3) exhibited maximum shielding efficiency in the range of 55-38 dB with absorption as an overall dominant shielding mechanism. The reflection loss of NGMC3 was found to be in the range of -90 to -77 dB with minima at -103 dB (at 2.9 GHz). Such outstanding electromagnetic wave absorption performance of NRGO/MnCo
O
nanocomposite compared to several other metal cobaltates could be attributed to the formation of percolated network assisted electronic polarization, interfacial polarization and associated relaxation losses, conductance loss, dipole polarization and corresponding relaxation loss, impedance matching, and magnetic resonance to some extent.
Highly mismatched alloys are of substantial interest for composition-dependent bandgap tunability for solar cell applications. Using low-energy ion implantation and subsequent thermal treatment, we ...have synthesized ZnTe nanocrystals from Te/ZnO bilayer thin films. However, only thermal treatment without ion implantation does not show any ZnTe nanocrystal characteristics that demonstrate the role of defects via ion implantation in nucleation growth. High-resolution transmission electron microscopy measurements confirmed the nanocrystalline growth of ZnTe and ZnTeO3 inside the mixed layer of ZnO and Te. From X-ray diffraction, it has been observed that a critical fluence of ions is required to produce a certain quantity of defects to assist in stoichiometric ZnTe formation. The absorption spectroscopy illustrates dual bandgap in the mixed alloys. Cathodoluminescence spectroscopy confirms two visible emission bands at 2.1 eV and 2.35 eV corresponding to the ZnTe and ZnO defect band along with the near band UV emission of ZnO at 3.26 eV. Such composition-dependent bandgap and light emission tunability from a mixed alloy are suitable for semiconductor device technology and energy harvesting.
•Low energy ion implantation mixed the ZnO/Te thin films to form highly mismatched alloys.•The thermal treatment after ion implantation assists in forming ZnTe nanocrystals.•Dual direct bandgap for ZnTe and ZnO has been observed and tuned with ion fluence.•The cathodoluminescence properties are also tuned with ion fluence.•The defect density helped to form crystalline alloy phases of ZnO, ZnTeO3, Te, and ZnTe nanocrystals from the thin films.
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•Prorteases (Mpro and PLpro) are part of the replication machinery of corona virus.•Mpro and PLpro inhibitors may serve as therapeutic weapons against SARS-CoV-2.•An exquisite picture ...of the recent coronavirus protease inhibitors is provided.•Experimental screening approaches are also highlighted.•Challenges in the development of effective as well as drug like protease inhibitors is also discussed.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) brutally perils physical and mental health worldwide. Unavailability of effective anti-viral drug rendering global threat of COVID-19 caused by SARS-CoV-2. In this scenario, viral protease enzymes are crucial targets for drug discovery. This extensive study meticulously focused on two viral proteases such as main protease (Mpro) and papain-like protease (PLpro), those are essential for viral replication. This review provides a detail overview of the targets (Mpro and PLpro) from a structural and medicinal chemistry point of view, together with recently reported protease inhibitors. An insight into the challenges in the development of effective as well as drug like protease inhibitors is discussed. Peptidomimetic and/or covalent coronavirus protease inhibitors possessed potent and selective active site inhibition but compromised in pharmacokinetic parameters to be a drug/drug like molecule. Lead optimization of non-peptidomimetic and/or low molecular weight compounds may be a better option for oral delivery. A masterly combination of adequate pharmacokinetic properties with coronavirus protease activity as well as selectivity will provide potential drug candidates in future. This study is a part of our endeavors which surely dictates medicinal chemistry efforts to discover effective anti-viral agent for this devastating disease.
Crystallin proteins undergo various posttranslational modifications with aging of eye lens. Oxidation of tryptophan (Trp) residues of a major γ-crystallin namely human γD-crystallin (HGD) was found ...to be inhibited by a naturally occurring flavonoid hesperetin at relatively low concentration mostly due to its antioxidant activity. Further the molecular interactions between HGD and hesperetin were elucidated on the basis of the quenching of Trp fluorescence of the protein by the flavonoid. Ground state complexation between HGD and hesperetin caused static quenching of the Trp fluorescence of HGD. Binding and quenching constants were in the order of (103- 104 M−1). Energy transfer from protein to hesperetin was suggested by FRET calculations. Thermodynamic parameters reveal significant hydrophobic association between the protein and hesperetin. Synchronous fluorescence and CD spectroscopic results had ruled out conformational changes in the protein due to binding of hesperetin. Docking studies suggested the proximity of hesperetin with Trp 42, which largely corroborates our experimental findings.
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The pursuit of sustainable solutions to address the global energy crisis has led to a keen interest in the advancement of cost-effective and multifunctional electrochemical systems. ...These systems aim to achieve both zero-carbon emissions and the dual capability to convert and store energy efficiently. The electrochemical splitting of water is one way to create carbon–neutral, clean hydrogen gas. Electrocatalysis and hydrogen evolution in general depends not only on the catalyst but also on its nano- and microstructure, which influences local chemical conditions and hydrogen gas bubble detachment. Therefore, rapid screening of not only potential catalysts but also various structured surfaces is needed for effective electrode fabrication. The fused deposition modeling (FDM) method of 3D printing is frequently used for electrode fabrication using conducting filaments; however, its micro-structuration resolution is limited. Stereolithography can produce complex and fine structures; however, the resins are not conductive and therefore the structures are not suitable for electrode fabrication. In this work, we have fabricated a substrate with high-resolution needle array architecture using stereolithographic (SLA) 3D printing and coated it with Co3Te4-CoTe2 (COT) nanofiber for water splitting and energy storage. The SLA 3D-printed cobalt telluride electrodes showed appreciable performance as a photoelectrocatalyst for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), acting as a bifunctional catalyst. We also demonstrated fabrication of a cobalt telluride based SLA 3D-printed supercapacitor device with multiscale hierarchy. The SLA 3D-printed supercapacitor device exhibited good electrochemical behavior along with high cycling stability. In general, we show here a universal method for SLA conductive electrode fabrication with hierarchical structuring of functional elements and suitable for various applications.
The present work is focused on the synthesis of bismuth sulfide (Bi 2 S 3 ) nanorod/reduced graphene oxide (RGO) composites via a one-step hydrothermal method using GO and bismuth nitrate in 5 : 1, 3 ...: 1 and 2 : 1 weight ratios and their characterization. The morphological studies revealed the formation of homogeneously dispersed Bi 2 S 3 nanorods on RGO sheets along with occasional wrapping in the Bi 2 S 3 nanorod/RGO (3 : 1) composite. XRD, FTIR, Raman and XPS studies suggested the incorporation of Bi 2 S 3 in RGO sheets. The galvanostatic charge–discharge measurements showed that the Bi 2 S 3 nanorod/RGO (3 : 1) composite exhibited the highest specific capacitance (1932 F g −1 ) at 1 A g −1 in the presence of 2 M aqueous KOH in a three-electrode cell. This is ascribed to the enhanced contact area between metal sulfide nanoparticles and RGO, increased conductivity and synergistic effect of Bi 2 S 3 and RGO. The optimized Bi 2 S 3 nanorod/RGO (3 : 1) composite also maintained an excellent cycling stability with ∼100% capacitance retention after 700 cycles. It is noted that the supercapacitor performance of the Bi 2 S 3 nanorod/RGO (3 : 1) composite was better than group V and VI metal chalcogenides and their nanocomposites reported in several previous studies.
Recently, porous nanostructured transition metal oxides with excellent electrochemical performance have become a new class of energy storage materials for supercapacitors. The ever-growing global ...demand of electrically powered devices makes it imperative to develop renewable, efficient and reliable electrochemical energy storage devices. This review article focuses on the Ni based transition metal oxides and their composite electrode materials including carbons, metals and transition metal oxides for supercapacitor applications, providing an overview on the charge mechanisms, methodologies and nanostructures discovered in recent years, and latest research findings. The NiO and their composites possess higher reversible capacity, good structural stability, and have been studied for usage as novel electrode materials for supercapacitors. Their fine-tuned physical and chemical properties make them ideal candidates for supercapacitor applications as they possess higher accessible electroactive sites, which will provide both high power density and also high energy density. Moreover, synergistic effects can be derived from the constituent materials of the NiO based composite electrodes. The potential problems like device fabrication, measurement techniques, and future prospects of utilizing these materials as supercapacitor electrodes highlighting the fundamental understanding of the relationship between electrochemical and structural performances are also discussed.
•NiO and their composite electrodes for supercapacitor applications are reviewed.•Charge storage mechanisms, methodologies and latest findings are discussed.•The potential problems in device fabrication and commercialization are analyzed.•Summarized the thumb rule for the selection of materials for supercapacitors.
The evolution of high electromagnetic absorption materials is essential in the fast growing electronic industry in overcoming electromagnetic pollution. In view of this, a series of Ni ...nanoparticle-decorated functionalized graphene sheets (FG/Ni) are synthesized by a solvothermal method using different ratios of FG/Ni precursors. Subsequently, FG/Ni is subjected to in situ polymerization of aniline to form FG/Ni/PANI ternary composites and characterized. The total electromagnetic interference shielding efficiency (SET) measurements on FG/Ni/PANI with an optimized FG/Ni ratio (50 mg:600 mg NiCl2·6H2O) exhibit enhanced performance, i.e., ∼47–65 dB (2–3.8 GHz) and ∼65–45 dB (3.8–8 GHz), following absorption as the dominant mechanism due to the matching of dielectric loss and magnetic loss. It is anticipated that such excellent performance of robust FG/Ni/PANI ternary composites at a very low thickness (0.5 mm) has great potential in the application of microwave-absorbing materials.
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