Strategically Designed Pd-Induced Changes in Alkaline Hydrogen Evolution Reaction and Oxygen Evolution Reaction Performances of Electrochemical Water Oxidation by the Galvanically Synthesized MoO2/MoO3 Composite Thin Film.

Electrochemical water oxidation is believed to be an effective pathway to produce clean, carbon-free, and environmentally sustainable green energy. In this work, we report a simple, easy-to-construct, facile, low-cost, and single-step galvanic technique to synthesize a Pd-supported temperature-assisted MoOx thin film nanocomposite for effective water oxidation. The most suitable nanocomposite exhibits very low overpotential at 10 mA/cm2 with smaller Tafel slope values for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) processes in an alkaline medium. The formation of a metal oxide-metal junction accelerates the growth of more active sites, promoting induced electronic synergism at the MoOx-Pd interface. This endows higher electrical conductivity and faster electron transfer kinetics, thus accelerating the faster water dissociation reaction following the Tafel-Volmer mechanism to boost the HER process in an alkaline medium. The excellent electrochemical HER and OER performances of our electrocatalyst even supersede the accomplishments of the benchmark catalysts Pt/C and RuO2. Moreover, neither of these two catalysts demonstrates both catalytic reactions, i.e., HER and OER at the same time, which have been observed for our synthesized catalyst. Our findings illustrate the potential of a thin-film MoOx-Pd nanocomposite to be an exceedingly effective electrocatalyst developed by interface engineering strategies. This also provides insight into designing several other semiconductor composite catalysts using simple synthesis techniques for highly efficient HER/OER processes that could be alternatives to benchmark electrocatalysts for water electrolysis.

Polyaniline/Reduced Graphene Oxide Composite-Enhanced Visible-Light-Driven Photocatalytic Activity for the Degradation of Organic Dyes.

Creation of an innovative composite photocatalyst, to advance its performance, has attracted researchers to the field of photocatalysis. In this article, a new photocatalyst based on polyaniline/reduced graphene oxide (PANI/RGO) composites has been prepared via the in situ oxidative polymerization method employing RGO as a template. For thermoelectric applications, though a higher percentage (50 wt %) of RGO has been used, for photocatalytic activity, lesser percentages (2, 5, and 8 wt %) of RGO in the composite have given a significant outcome. Furthermore, photoluminescence (PL) spectra, time-resolved fluorescence spectra, and Brunauer-Emmett-Teller surface area analyses confirmed the improved photocatalytic mechanism. PANI/RGO composites under visible light irradiation exhibit amazingly improved activity toward the degradation of cationic and anionic dyes in comparison with pristine PANI or RGO. Here, a PANI/RGO composite, with 5 wt % RGO(PG2), has emerged as the best combination with the degradation percentages of 99.68, 99.35, and 98.73 for malachite green, rhodamine B, and congo red within 15, 30, and 40 min, respectively. Experimental findings show that the introduction of RGO can relieve the agglomeration of PANI nanoparticles and enhance the light absorption of the materials due to an increased surface area. Moreover, the PG2 composite also showed excellent photocatalytic activity to reduce noxious Cr(VI). The effective removal of Cr(VI) up to 94.7% at pH 2 was observed within only 15 min. With the help of the active species trapping experiment, a plausible mechanism for the photocatalytic degradation has been proposed. The heightened activity of the as-synthesized composite compared to that of neat PANI or RGO was generally because of high concentrations of •OH radicals and partly of •O2 - and holes (h+) as concluded from the nitroblue tetrazolium probe test and photoluminescence experiment. It is hoped that the exceptional photocatalytic performance of our work makes the conducting polymer-based composite an effective alternative in wastewater treatment for industrial applications.

A turn-on fluorogenic chemosensor for Fe3+ and a Schottky barrier diode with frequency-switching device applications.

A novel highly sensitive and selective fluorescent chemosensor L has been synthesized and characterized by various physicochemical techniques. In 3 : 7 water : MeCN (v/v) at pH 7.2 (10 mM HEPES buffer, µ = 0.05 M LiCl), it selectively recognizes Fe3+ through 1 : 1 complexation resulting in a 106-fold fluorescence enhancement and a binding constant of 8.10 × 104 M-1. The otherwise non-fluorescent spirolactam form of the probe results a dual-channel (absorbance and fluorescence) recognition of Fe3+via CHEF (chelation enhanced fluorescence) through the opening of the spirolactam ring. We have also carried out fluorescence titration and anisotropy (r) studies in pure water in the presence of SDS (sodium dodecyl sulphate). Based on the dependence of FI (fluorescence intensity) and r on [SDS] it was proposed that the probe is trapped between two SDS monolayers which again interact among themselves by ππ stacking. As a result, there is an increase in FI up to [SDS] ∼ 7 mM - a phenomenon reminiscent of aggregation-induced enhancement of emission (AIEE). Beyond this concentration of SDS (7 mM), micelle formation takes place and the ππ stacked polymer now becomes a monomer and is trapped inside the micellar cavity. As a result, there is a decrease in FI at [SDS] > 7 mM. But for anisotropy, it increases with [SDS] beyond 7 mM. Ligand, metal, and SDS interactions are well established through different optical and morphological studies. [L-Fe(NO3)]2+ thin films on FTO (Fluorine-doped Tin Oxide) glass substrates have been designed with the help of the spin-coating deposition technique. The deposited film of thickness 1.6 × 10-5 cm is well characterized by optical band gap calculation with a direct band gap, εg ∼ 1.6 eV. FESEM was also performed for the [L-Fe(NO3)]2+/FTO film. The current-voltage characteristics were measured by the two-probe technique. Light-dependent exciton generation was carried out by taking the top and bottom contacts with graphite paste on FTO and on the [L-Fe(NO3)]2+ films for the measurement of switching behavior. The response ratio curve for the light-induced frequency-switching phenomena has been obtained. The frequency taped here is the oscillation frequency of the photo-generated electron and the hole in an exiton. Thus, the light-induced frequency-switching behavior and Schottky barrier diode characteristics of the material were established.

Fabrication of SnO2/α-Fe2O3, SnO2/α-Fe2O3-PB heterostructure thin films: enhanced photodegradation and peroxide sensing.

We report the synthesis of SnO2/α-Fe2O3 heterostructure thin films by employing two-step processes: galvanic and chemical deposition. Fe2O3 is a narrow band gap semiconductor and has short hole diffusion length. Therefore, the photogenerated electrons and holes are not easy to separate in Fe2O3. Combining Fe2O3 to SnO2, a wide-energy-gap semiconductor having suitable valence band and conduction band position is a promising candidate for the photo catalysts. The chemical modification of this heterostructure was achieved by electro-active Prussian blue (PB) molecule. The photocatalytic activities of SnO2, α-Fe2O3, SnO2/α-Fe2O3, and SnO2/α-Fe2O3-PB thin films were investigated for organic dye degradation. It was observed that the coupled and combined modified systems showed better reactivity compared to individual single-component materials. The electrocatalytic activity of the synthesized thin films has also been studied where hydrogen peroxide (H2O2) was taken as a model compound. Amperometric study also reveals that the couple and combined modified thin films are more effective at sensing hydrogen peroxide (H2O2) than single-component materials.

Nickel oxide thin film from electrodeposited nickel sulfide thin film: peroxide sensing and photo-decomposition of phenol.

A novel non-enzymatic peroxide sensor has been constructed by using nickel oxide (NiO) thin films as sensing material, which were prepared by a two-step process: (i) electrodeposition of nickel sulfide (NiS) and (ii) thermal air oxidation of as-deposited NiS to NiO. The resultant material is highly porous and comprises interconnected nanofibers. UV-Vis spectroscopy, FTIR spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM) were used for a complete characterization of nanostructured NiO thin films. Cyclic voltammetry study shows that NiO/ITO electrode facilitates the oxidation of hydrogen peroxide and exhibits excellent catalytic activity towards its sensing. The amperometric study of NiO/ITO was carried out to determine the sensitivity, linear range, detection limit of the proposed sensor. The sensor exhibits prominent electrocatalytic activity toward the oxidation of H2O2 with a wide linear range and a low detection limit. The possible use of the synthesized NiO thin films as an effective photocatalyst for the decomposition of phenol is also discussed.

Retrospective observational study of penetrating keratoplasty in the management of non-responsive microbial keratitis.

Microbial keratitis tops the list of the diseases leading to corneal blindness. Corneal transplant, either partial or full thickness, is the most helpful technique for infective keratitis that remains non- responsive, even with the most suitable medical treatment. Aims of this study are to evaluate the success of therapeutic penetrating keratoplasty in non-responsive microbial keratitis in eradication of infection, restoration of anatomical integrity of the globe and prevention of complication that influence the visual prognosis in a positive way. Result of the retrospective study of 60 patients who underwent therapeutic penetrating keratoplasty, following infected keratitis showed restoration of anatomical integrity in 51 cases (85%). Success rate of penetrating keratoplasty was higher in non- perforated (92%) than in perforated group (74.28%) and in non-mycotic than in mycotic group. Penetrating keratoplasty in non-responsive infected keratitis is thus helpful.

Effect of anti-oxidant on tear film in patients suffering from diabetes mellitus.

To study the effects of anti-oxidant on tear film parameters in patients with diabetes mellitus, a total of 100 patients of diabetes mellitus with defective Schirmer test and tear film break-up time were enrolled in this study and they were given vitamin C (1000 mg/day) and vitamin E (400 IU/day) for 30 days. Schirmer test and tear break-up, time were re-examined after 1 month. There was significant improvement in values for Schirmer test (p < 0.001) and tear break-up time. Oxidative stress has an influence on how diabetes mellitus affects various systems of body. This study clearly depicted im- portant roles of vitamins C and E in improving the well-being of the ocular surface.

Electrocatalytic activity of silver nanoparticles modified glassy carbon electrode as amperometric sensor for hydrogen peroxide.

A simple chemical route has been applied for the preparation of quasi-spherical silver (Ag) nanoparticles (NPs) with average diameter of 265 and 8 nm. The as prepared products were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and UV-vis absorption spectroscopy. Ag NPs immobilized on glassy carbon (GC) electrode showed a superior electrocatalytic activity for the reduction of hydrogen peroxide (H2O2) in aqueous medium. The fabricated electrode was also applied for the amperometric detection of H2O2 and showed a favorable response at an applied potential of -0.5 V (vs. Ag/AgCl). The results demonstrate that the fabricated electrode has potential application for hydrogen peroxide sensor.

Photocatalytic degradation of organic dye on porous iron sulfide film surface.

Thin films of nanocrystalline and porous FeS(2) with marcasite phase have been deposited from a greenish-blue iron nitroprusside precursor film, which readily gives FeS(2) on reacting with an aqueous solution of sodium sulfide. High resolution X-ray diffraction (HRXRD) pattern indicated the formation of polycrystalline and orthorhombic (marcasite) phase of FeS(2), whereas the field emission scanning electron microscopy (FESEM) showed the morphology of the films to be consisted of grains of average 25 nm diameter with unevenly distributed numerous pores. Optical characterization (UV-Vis and photoluminescence) revealed significant amount of blueshift in the band gap energy of the deposited material, which is attributed to the strong quantum confinement effect exerted by the FeS(2) nanocrystals. The deposited FeS(2) films showed good photocatalytic activity toward the degradation of Rose Bengal dye and could be found efficient for wastewater treatment.

A novel amperometric biosensor for hydrogen peroxide and glucose based on cuprous sulfide nanoplates.

A facile, greener and template free route has been developed to produce cuprous sulfide (Cu2S) nanoplates (NPs) with average diameters of 70-150 nm, via one step solvothermal decomposition of a single-source precursor (SSP) Cu(ACDC)2 [ACDC = 2-aminocyclopentene-1-dithiocarboxylate] in the presence of ethylenediamine (EN) and triethylenetetramine (TETA) as structure orienting agents. The precursor complex and nanomaterials were thoroughly characterized by several common techniques and measurements, which give the composition and characteristics of the materials. Amperometric biosensors for hydrogen peroxide (H2O2) and glucose have been constructed by immobilizing the synthesized Cu2S NPs in glutaraldehyde on a glassy carbon (GC) electrode using a direct drop-coating method. The proposed sensor has displayed faster response, high and reproducible sensitivity (64.27 µA mM-1) with linear range of 10 µM to 3.75 mM, towards the electrochemical biosensing of H2O2 at -0.35 V (vs. Ag/AgCl). The sensor also showed high and reproducible sensitivity (61.67 µA mM-1) towards glucose determination with linear range of 10 µM to 3.1 mM. The anti-inference ability of electroactive molecules and favorable stability are some of the advantages of the proposed sensor. Finally, using the sensor we have determined the glucose concentration in a human blood serum sample. The results strongly demonstrate the usefulness of Cu2S NPs for biosensor design and other biological applications.

Managing post acute congestive phase by combined manual small incision cataract surgery and trabeculectomy: a prospective study.

The purpose of the study was to evaluate the therapeutic efficacy of manual small incision cataract surgery (SICS) and trabeculectomy as management option for acute angle closure glaucoma. The first 6 cases of 14 cases of acute angle closure glaucoma seen over a period of 18 months underwent surgical peripheral buttonhole iridectomy (PBHI) after their intra-ocular pressure (IOP) was controlled medically. Subsequently 8 cases underwent manual SICS+trabeculectomy as an alternative procedure after their IOP control who needed further surgery and overall patients' comfort. The results showed sustained visual acuity remained 6/9 or better in all the patients of SICS + trabeculectomy group, compared 6/12 or worse in the PBHI group. Mean non-contact tonometry reading at the end of 6 weeks was 10.2 mm Hg in the second group compared to 14.6 in the first group. None of the patients in the second group ever needed surgery in a 4-month follow-up, whereas 3 patients in the first group had to be operated again for cataract or uncomplicated IOP. Manual SICS+ trabeculectomy offers a good, economical and rational therapeutic alternative to traditional PBHI in the postcongestive phase.

Sodium bicarbonate versus sodium hyaluronidase in ocular regional anaesthesia--a comparative study.

It has been reported that alkalinisation of an anaesthetic medication enhances the rate of onset of regional anaesthesia. The purpose of this study therefore was to find out whether alkalinisation really hastened peribulbar anaesthesia as given prior to routine cataract surgery. Two hundred and forty otherwise healthy patients with bilateral cataracts were selected for this study irrespective of their demographic attributes. The first eye (group FE) received a routine peribulbar block with a standard solution of 6 ml of 2% lignocaine mixed with 15 IU/l units of sodium hyaluronidase at a pH of 4.6. The second eye (group SE) was taken up for surgery after one week and received a peribulbar block with 6 ml lignocaine 2% mixed with 7.5% sodium bicarbonate at a pH 7.4. The time taken for onset of akinesia in both the situations was measured to the last minute with the aid of a stop watch by an independent observer. Thirty-five per cent of patients in group FE had complete akinesia at the end of 5 minutes, another 60% at the end of 7 minutes and remaining 6% at 10 minutes. Sixty-eight per cent of patients in group SE had complete akinesia at the end of 5 minutes and 100% at the end of 7 minutes. No anaesthesia related ocular or systemic complications were seen in any group. Sodium bicarbonate buffered peribulbar block is faster than routine hyaluronidase augmented block with a reduced time of onset of akinesia.

Synthesis of FeS and FeSe nanoparticles from a single source precursor: a study of their photocatalytic activity, peroxidase-like behavior, and electrochemical sensing of H2O2.

Nanocrystalline FeS and FeSe compounds were prepared by solvothermal decomposition of a precursor complex [Fe(3)(µ(3)-O)(µ(2)-O(2)CCH(2)Cl)(6)(H(2)O)(3)]NO(3)·H(2)O in the presence of thiourea and sodium selenite, respectively. The as-obtained products were characterized by X-ray diffraction analysis (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and UV-vis spectroscopic techniques. Structural analyses revealed that the FeS and FeSe nanoparticles (NPs) are composed of needle-like and spherical particles, respectively. The FeS and FeSe NPs showed photocatalytic activity for the decomposition of rose bengal (RB) and methylene blue (MB) dyes under white light illumination. They also showed good catalytic activity toward oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H(2)O(2) and followed Michaelis-Menten kinetics. In addition, both FeS and FeSe NPs exhibited electrocatalytic activity toward reduction of hydrogen peroxide, which on immobilization on glassy carbon (GC) electrodes perform as amperometric sensors for detection of H(2)O(2). At pH 7.0, the FeS/GC showed a linear range for detection of H(2)O(2) from 5 to 140 µM, while for FeSe/GC the range was 5 to 100 µM.

Chronic administration of caffeine: effect on the activities of hepatic antioxidant enzymes of Ehrlich ascites tumor-bearing mice.

Chronic ingestion (for 22-30 consecutive days) of caffeine (20 mg/kg/day, p.o.) increased the activities of the hepatic enzymes- catalase (CAT) and superoxide dismutase (SOD) and decreased its lipid peroxidation (LP) in mice. Development of Ehrlich ascites carcinoma (EAC) cell decreased the activities of hepatic CAT and SOD and increased LP. But pretreatment of caffeine for 12 consecutive days and continuation of its treatment during the course of development of EAC cells restored the EAC cell-induced changes in liver CAT, SOD and LP to their corresponding control values. Thus, the present results by confirming the results of others previously published, suggest that caffeine is an antioxidant and may act as an anticarcinogen.