Large-scale synthesis of porous NiCo2O4 and rGO-NiCo2O4 hollow-spheres with superior electrochemical performance as a faradaic electrode

Synthesis of nanocomposites of metal oxide and reduced graphene oxide (rGO) in a hollow spherical form has been proved to be challenging due to the crumbling effect of rGO. In this paper, we report a simple, cost-effective and large-scale synthetic strategy for producing porous NiCo2O4 hollow spheres as well as rGO-NiCo2O4 hollow spheres through spray drying of respective metal ammonium carbonate complex solutions followed by calcination. During the synthesis process, ammonium carbonate played a pivotal role in hollow sphere formation through easy decomposition into CO2 and NH3 and enhancement of internal pressure of atomized droplets helped to overcome the crumbling effect of rGO. The synthesized hollow spheres are porous, made of 7-12 nm particles with an average diameter of 2-3 mm and a surface area of 76 m(2) g(-1) for pristine NiCo2O4 and 21 m(2) g(-1) for rGO-NiCo2O4. Observance of distinct redox peaks in cyclic voltammetry (CV) indicates that the electrochemical charge storage mechanism of NiCo2O4 is non-capacitive and somewhat battery type in nature. The synthesized rGO-NiCo2O4 hollow spheres showed a specific capacity as high as 427 C g(-1) (971 F g(-1)) at a current density of 0.5 A g(-1) which is much superior to that of pristine NiCo2O4 hollow spheres (183 C g(-1)). rGO-NiCo2O4 also exhibited an excellent rate performance with capacities of 385.3, 345.4, 256, 169 and 89 C g(-1) at current densities of 1, 2, 5, 10 and 20 A g(-1), respectively and 76% retention of capacity after 5000 cycles at 10 A g(-1). Furthermore, studies on AC//rGO-NiCo2O4 asymmetric cells show that the energy storage performance of rGO-NiCo2O4 hollow spheres obtained by the present scalable and cost-effective process is quite comparable, or even superior to those reported for NiCo2O4 synthesized through sophisticated and costly synthetic protocols

Principal components′ analysis of multifocal electroretinogram in retinitis pigmentosa

Aims : To determine waveforms of multifocal electroretinogram (mfERG) in patients with retinitis pigmentosa (RP) contributing significantly to the overall retinal response by using principal components′ analysis. Settings and Design: Prospective, non-randomized, single-visit, observational, case-control study from a single tertiary ophthalmic center. Materials and Methods: Patients with various forms of RP underwent mfERG testing for a period of one year. The first-order kernel responses of RP cases were compared with concurrently recruited healthy controls. Statistical Analysis Used: Parametric data was analyzed using the unpaired t test for differences between the implicit time and amplitudes of cases and controls. Principal components′ analysis was done for each implicit time and amplitude in cases with RP using the Varimax rotation method. Results: From March 2006 to March 2007, 24 cases with typical RP (56%, 47 eyes) were included in the final analysis. Their mean age was 33.7 years (19-69 ± 15.5 years). Comparison of latencies and amplitudes among RP cases with log MAR acuity ≤ 0.18 and those > 0.18, revealed significant difference in the implicit time (P1) in Ring 2 only (P=0.028). Two components (predominently from Ring 1 and 2) each contributing 66.8% and 88.8% of the total variance in the data for latencies and amplitudes respectively, were seen. Conclusions : The first two rings of the mfERG contributed to the variance of waveforms in RP, irrespective of the visual acuity and poor visual field results

TiO2-rGO nanocomposite hollow spheres: large scale synthesis and application as an efficient anode material for lithium-ion batteries

We report here a controllable large-scale synthesis protocol for TiO2-rGO nanocomposites with a hollow spherical morphology by a novel aerosol-assisted spray drying method followed by calcination. The developed strategy is easy to scale-up without significant change in morphology. The precursors used for the synthesis are aqueous titanium ammonium peroxo-carbonate complex (TAPCC) solution, being decomposable at low temperatures, and an aqueous graphene oxide (GO) suspension; no additive or structure-directing agent is required. Both the precursors play vital roles in hollow sphere formation. The enhanced internal pressure inside the atomized droplets built-up in situ through decomposition of TAPCC forming gaseous CO2, NH3, O-2 and H2O vapour, helps overcome the crumpling effect of GO. The sheet structure of GO provides sufficient mechanical strength to prevent bursting of the expanded droplets. The synthesized TiO2-rGO hollow spheres are porous, composed of 10-20 nm TiO2 particles dispersed on the surfaces of rGO with a surface area of 86 m(2) g(-1). The synthesized TiO2-rGO composites showed superior electrochemical performance as lithium-ion battery (LIB) anode with capacity values of 265 mA h g(-1) (10 wt% rGO) and 274 mA h g(-1) (20 wt% rGO) at 18.8 mA g(-1) as compared to 236 mA h g(-1) for the pristine sample with a 2D flake-like morphology. This is due to the unique thin-walled hollow-spherical structure of TiO2-rGO composites, which provides a large number of electrochemically accessible active sites, favorable diffusion paths for Li+ ions and enhanced charge transport. Thus, the present synthetic method has great potential for large scale production of TiO2-rGO hollow spheres for application as anode in practical high-rate lithium-ion batteries

Protective Role of Black Tea Extract against Nonalcoholic Steatohepatitis-Induced Skeletal Dysfunction

Aim. This paper aimed to examine the chemoprotective actions of aqueous black tea extract (BTE) against nonalcoholic steatohepatitis- (NASH-) induced skeletal changes in rats. Material. Wistar rats (body wt. 155–175 g) of both sexes, aged 4–5 months, were randomly assigned to 3 groups; Group A (control), Group B (60% high-fat diet; HFD), and Group C (HFD + 2.5% BTE). Methods. Several urinary (calcium, phosphate, creatinine, and calcium-to-creatinine ratio) serum (alkaline phosphatase and serum tartrate-resistant acid phosphatase), and molecular markers of bone turnover (receptor activator of NF-κB ligand (RANKL), osteoprotegerin (OPG), and estrogen) were tested. Also, several bone parameters (bone density, bone tensile strength, bone mineral content, and bone histology) and calcium homeostasis were checked. Results. Results indicated that HFD-induced alterations in urinary, serum, and bone parameters as well as calcium homeostasis, all could be significantly ameliorated by BTE supplementation. Conclusion. Results suggest a potential role of BTE as a protective agent against NASH-induced changes in bone metabolism in rats

Nickel-Catalyzed Deamidative Step-Down Reduction of Amides to Aromatic Hydrocarbons

To date, cleavage of the C−N bond in aromatic amides has been achieved in molecules with a distorted constitutional framework around the nitrogen atom. In this report, a nickel-catalyzed reduction of planar amides to the corresponding lower hydrocarbon homologue has been reported. This involves a one-pot reductive cleavage of the C−N bond followed by a tandem C−CO bond break in the presence of a hydride source. Substrate scope circumscribes deamidation examples which proceed via oxidative addition of nickel in the amide bonds of nontwisted amides. Mechanistic studies involving isolation and characterization of involved intermediates via different spectroscopic techniques reveal a deeper introspection into the plausible catalytic cycle for the methodology

Synthesis, Characterization, and Reactivity of High-Valent Carbene Dicarboxamide-Based Nickel Pincer Complexes

High-valent metal–fluoride complexes are currently being explored for concerted proton–electron transfer (CPET) reactions, the driving force being the high bond dissociation energy of H–F (BDEH–F = 135 kcal/mol) that is formed after the reaction. Ni(III)–fluoride-based complexes on the pyridine dicarboxamide pincer ligand framework have been utilized for CPET reactions toward phenols and hydrocarbons. We have replaced the central pyridine ligand with an N-heterocyclic carbene carbene to probe its effect in both stabilizing the high-valent Ni(III) state and its ability to initiate CPET reactions. We report a monomeric carbene-diamide-based Ni(II)–fluoride pincer complex that was characterized through 1H/19F NMR, mass spectrometry, UV–vis, and X-ray crystallography analysis. Although carbenes and deprotonated carboxamides in the Ni(II)–fluoride complex are expected to stabilize the Ni(III) state upon oxidation, the Ni(III)/Ni(II) redox process occurred at very high potential (0.87 V vs Fc+/Fc, dichloromethane) and was irreversible. Structural studies indicate significant distortion in the imidazolium “NCN” carbene plane of Ni(II)–fluoride caused by the formation of six-membered metallacycles. The high-valent NiIII–fluoride analogue was synthesized by the addition of 1.0 equiv CTAN (ceric tetrabutylammonium nitrate) in dichloromethane at −20 °C which was characterized by UV–vis, mass spectrometry, and EPR spectroscopy. Density functional theory studies indicate that the Ni-carbene bond elongated, while the Ni–F bond shortened upon oxidation to the Ni(III) species. The high-valent Ni(III)–fluoride was found to react with the substituted phenols. Analysis of the KIE and linear free energy relationship correlates well with the CPET nature of the reaction. Preliminary analysis indicates that the CPET is asynchronous and is primarily driven by the E0′ of the Ni(III)–fluoride complex

Incidence, clinical features, risk factors, and outcomes of Intraocular inflammation following Brolucizumab in Indian eyes – A multicentric study

Purpose: To report the incidence, clinical features, potential risk factors, and outcomes of intraocular inflammation (IOI) following brolucizumab in Indian eyes. Methods: All consecutive patients diagnosed with brolucizumab-induced IOI from 10 centers in eastern India between October 2020 and April 2022 were included. Results: Of 758 injections given during the study period across centers, 13 IOI events (1.7%) were recorded attributable to brolucizumab. The IOI occurred after the first dose in two eyes (15%) (median 45 days after brolucizumab), second dose in six eyes (46%) (median = 8.5 days), and third dose (39%) in the remaining five eyes (median 7 days). Reinjections of brolucizumab were administered at a median interval of 6 weeks (interquartile range = 4–10 weeks) in the 11 eyes, where IOI occurred after the second or third dose. Eyes that experienced IOI after the third dose had received a significantly greater number of previous antivascular endothelial growth factor injections (median = 8) compared to those who developed it after the first or second dose (median = 4) (P = 0.001). Anterior chamber cells were seen in almost all eyes (n = 11, 85%), while peripheral retinal hemorrhages were seen in two eyes, and one eye showed branch artery occlusion. Two-thirds of patients (n = 8, 62%) recovered with a combination of topical and oral steroids, while remaining recovered with topical steroids alone. Irreversible visual loss was not seen in any eye, and median vision recovered to pre-IOI levels by 3 months' time point. Conclusion: Brolucizumab-induced IOI was relatively rare, occurring in 1.7% of eyes, was more common after the second or third injection, especially in those who required frequent reinjections every 6 weeks, and occurred earlier with increasing number of previous brolucizumab injections. Continued surveillance is necessary even after repeated doses of brolucizumab