Pd Nanoparticle-Decorated Novel Ternary Bi2O2CO3-Bi2MoO6-CuO Heterojunction for Enhanced Photo-electrocatalytic Ethanol Oxidation.

Recently, photo-electrooxidation of fuel using a noble metal-semiconductor junction has been one of the most promising approaches in fuel cell systems. Herein, we report the development of a Pd-supported Bi2MoO6-Bi2O2CO3-CuO novel ternary heterojunction for ethanol oxidation in alkali in the presence and absence of visible light. Various spectroscopic and microscopic characterization techniques confirm strong coupling between palladium nanoparticles and Bi2MoO6-Bi2O2CO3-CuO ternary heterojunction supports. The photo-electrocatalytic efficacy of the synthesized catalysts was inspected by cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS). The CV study reveals that the forward peak current density (in mA mg-1 of Pd) of the synthesized quaternary heterojunction was about 1482.5, which is 2.4, 4, and 4.6 times higher than that of Pd/CuO (608.3), Pd/Bi2MoO6-Bi2O2CO3 (368.3), and similarly synthesized Pd catalyst (321.5) under visible light radiation. The best heterojunction catalyst shows 2.21-fold higher peak current density in visible light compared to that in dark. CA study reveals that after operation for 6000 s, the current density of the quaternary electrode is 1.5 and 3.4 times greater than that of Pd/CuO and Pd/C catalysts, respectively. The greater photocurrent response, lower photoluminescence (PL) emission intensity, and smaller semicircle arc in the Nyquist plot of the quaternary catalyst demonstrate the efficient segregation and higher charge transfer conductance of photogenerated charges to facilitate the photo-electrooxidation process of ethanol. The stability test shows that the quaternary catalyst loses only 9.8 and 7.7% of its maximum current density after 500 cycles of CV operation in the dark and light, respectively, indicating that light energy is more beneficial in establishing high stability. The dramatic enhancement of the photo-electrocatalytic activity of the quaternary electrode is owing to the lower band gap, high ECSA, enhanced charge separation of photogenerated carriers (e--h+), and all cocatalytic support of Bi2MoO6, Bi2O2CO3, and CuO in Pd/ Bi2MoO6-Bi2O2CO3-CuO under visible light radiation. The morphology and structure of the used quaternary catalyst are tested using FESEM and PXRD. Finally, ex situ FTIR spectroscopy and HPLC techniques help understand the ethanol electrooxidation reaction mechanism.

Size-Dependent Catalytic Activity of PVA-Stabilized Palladium Nanoparticles in p-Nitrophenol Reduction: Using a Thermoresponsive Nanoreactor.

Palladium nanoparticles (Pd NPs) of various average global diameters (2.1-7.1 nm) encapsulated with hydrophilic polymer polyvinyl alcohol (PVA) have been synthesized and used as catalysts for sodium borohydride assisted reduction of p-nitrophenol to p-aminophenol. The synthesized catalysts exhibit excellent and typical size-dependent catalytic activity in the green protocol. UV-visible absorption spectroscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy were employed to characterize the prepared Pd NPs. The kinetics of this reaction was easily monitored by a UV-visible absorption spectrophotometer. The mechanism of the reaction is explained by the Langmuir-Hinshelwood model. The catalytic performance increases with decreasing size of the synthesized nanoparticles. The apparent rate constants (k app × 103/s-1) of the catalytic reduction in the presence of Pd NPs of average diameters of 2.1, 3.35, 6.2, and 7.1 nm are determined as 8.57, 7.67, 6.16, and 5.04, respectively, at 298 K by using 2.91 mol % palladium nanocatalyst in each case. Moreover, the estimated activation energy of 22.2 kJ mol-1 obtained for Pd NPs with the smallest average diameter of 2.1 nm is very low as reported in the literature for the reduction. The influences of catalyst dose and concentration of p-nitrophenol on catalytic reduction are fully investigated. The catalyst with the largest diameter shows a temperature-sensitive property that might be due to the presence of a very low amount of rapped PVA used as stabilizer during the fabrication process. Thus, the synthetic protocol provides a unique fabrication process of a catalytically active thermoresponsive nanoreactor consisting of Pd NPs encapsulated into a PVA stabilizing agent.

Anodic Oxidation of Butan-1-ol on Reduced Graphene Oxide-Supported Pd-Ag Nanoalloy for Fuel Cell Application.

Reduced graphene oxide (RGO)-supported bimetallic Pd x Ag y alloy nanoparticles of various compositions were synthesized by one-pot coreduction of respective precursors with hydrazine for use in the anode catalysis of oxidation of butan-1-ol in alkali. The as-synthesized catalyst materials were characterized by microscopic, spectroscopic, and diffraction techniques. Cyclic voltammetry (CV), chronoamperometry, and polarization studies infer that a few Pd x Ag y materials exhibit an enhanced and synergistic catalytic activity in reference to Pd and Ag nanomaterials. Among the various RGO composites of Pd x Ag y alloy on graphite support, the one containing the Pd70Ag30@RGO composite is the best in catalytic activity. The cycle life of the catalyst is found to be very high, and PdO and Ag2O are found to be generated in the catalyst material with little change in the catalytic capability during the 100th cycle of CV operation. The addition of Ag upto 30 atom % in the Pd x Ag y alloy causes greater formation of butyraldehyde and butyl butanoate among the various products. Larger atom % of Pd helps to form sodium butyrate and sodium carbonate, as evident from the ex situ Fourier transform infrared and high-performance liquid chromatography study of the product mixtures and the separate CV studies of the intermediate products. A suitable mechanism is also proposed to fit the findings.

Magnetic, Pseudocapacitive, and H2O2-Electrosensing Properties of Self-Assembled Superparamagnetic Co0.3Zn0.7Fe2O4 with Enhanced Saturation Magnetization.

The present work explores the structural, microstructural, optical, magnetic, and hyperfine properties of Co0.3Zn0.7Fe2O4 microspheres, which have been synthesized by a novel template-free solvothermal method. Powder X-ray diffraction, electron microscopic, and Fourier transform infrared spectroscopic techniques were employed to thoroughly investigate the structural and microstructural properties of Co0.3Zn0.7Fe2O4 microspheres. The results revealed that the microspheres (average diameter ∼121 nm) have been formed by self-assembly of nanoparticles with an average particle size of ∼12 nm. UV-vis diffuse reflectance spectroscopic and photoluminescence studies have been performed to study the optical properties of the sample. The studies indicate that Co0.3Zn0.7Fe2O4 microspheres exhibit a lower band gap value and enhanced PL intensity compared to their nanoparticle counterpart. The outcomes of dc magnetic measurement and Mössbauer spectroscopic study confirm that the sample is ferrimagnetic in nature. The values of saturation magnetization are 76 and 116 emu g-1 at 300 and 5 K, respectively, which are substantially larger than its nanosized counterpart. The infield Mössbauer spectroscopic study and Rietveld analysis of the PXRD pattern reveal that Fe3+ ions have migrated from [B] to (A) sites resulting in the cation distribution: (Zn2+ 0.46Fe3+ 0.54)A[Zn2+ 0.24Co2+ 0.3Fe3+ 1.46]BO4. Comparison of electrochemical performance of the Co0.3Zn0.7Fe2O4 microspheres to that of the Co0.3Zn0.7Fe2O4 nanoparticles reveals that the former displays greater specific capacitance (149.13 F g-1) than the latter (80.06 F g-1) due to its self-assembled porous structure. Moreover, it was found that Co0.3Zn0.7Fe2O4 microspheres possess a better electrochemical response toward H2O2 sensing than Co0.3Zn0.7Fe2O4 nanoparticles in a wide linear range.

Electrochemical Energy Storage Properties of Ni-Mn-Oxide Electrodes for Advance Asymmetric Supercapacitor Application.

In this work, we report a facile one-spot synthesis process and the influence of compositional variation on the electrochemical performance of Ni-Mn-oxides (Ni:Mn = 1:1, 1:2, 1:3, and 1:4) for high-performance advanced energy storage applications. The crystalline structure and the morphology of these synthesized nanocomposites have been demonstrated using X-ray diffraction, field emission scanning electron microscopy, and transmission electron Microscopy. Among these materials, Ni-Mn-oxide with Ni:Mn = 1:3 possesses a large Brunauer?Emmett?Teller specific surface area (127 m2 g?1) with pore size 8.2 nm and exhibits the highest specific capacitance of 1215.5 F g?1 at a scan rate 2 mV s?1 with an excellent long-term cycling stability (?87.2% capacitance retention at 10 A g?1 over 5000 cycles). This work also gives a comparison and explains the influence of different compositional ratios on the electrochemical properties of Ni-Mn-oxides. To demonstrate the possibility of commercial application, an asymmetric supercapacitor device has been constructed by using Ni-Mn-oxide (Ni:Mn = 1:3) as a positive electrode and activated carbon (AC) as a negative electrode. This battery-like device achieves a maximum energy density of 132.3 W h kg?1 at a power density of 1651 W kg?1 and excellent coulombic efficiency of 97% over 3000 cycles at 10 A g?1.

Synthesis and characterization of biopolymer based hybrid hydrogel nanocomposite and study of their electrochemical efficacy.

A highly competent material, based on poly lactic acid (PLLA) grafted hydroxypropyl guar gum (HPG-g-PLLA) and polypyrrole/carboxylated multiwalled carbon nanotube (PPy/C-MWCNT) composite of various binary composition and copolymer of one of these nanocomposites have been synthesized successfully by in-situ polymerization. The environmentally affable nanocomposites have been characterized by spectroscopy, microscopy and thermogravimetry. Cytotoxicity of bio-nanocomposite has been inquired by cell viability study, which reveals its eco-friendly nature. The electrochemical properties of the biomaterials have been appraised by cyclic voltammetric studies. The PPy/C-MWCNT composite having 1 wt% C-MWCNT appears as the optimum composition from electrochemical studies. The hydrogel nanocomposite (HPG-g-PLLA5/0.5) copolymer behaves as a super ordinate material than pure PPy and PPy/C-MWCNT in every aspect of electrochemical properties like current density, stability, processibility and reversibility. Moreover the hydrogel nanocomposite, making electrode fabrication more simple and binder-free, nullifies all the interfacial complications arising from binders as well.

Phase control synthesis of α, ß and α/ß Bi2O3 hetero-junction with enhanced and synergistic photocatalytic activity on degradation of toxic dye, Rhodamine-B under natural sunlight.

Nano particles of a few α/ß Bi2O3 hetero-junctions of various compositions synthesized by one- pot hydrothermal method, exhibit exceptional and synergistic photo-catalytic activity for the degradation of Rhodamine-B in aqueous solution under natural sunlight. Pure α and pure ß Bi2O3 are also synthesized by control post heating of synthesized hetero-junction. The nano-materials were characterized by diffraction (XRD), microscopic and spectroscopic techniques. The XRD reveals α-ß phase hetero-junctions of Bi2O3 are made of α-Bi2O3 and ß-Bi2O3 with average dimensions within 13-113 and 5-71 nm respectively and having band gap range of 2.4- 2.9 eV. The spectrophotometrically determined % degradation of the dye and associated rate constant on the best hetero-junction are increased by 4.5(/2.1) and 3.3(/1.2) times than these on pure α (/ß). The effects of operational parameters and trapping agents have been analyzed. The maximum removal of the dye was achieved up to 99.6% in 3 h using 0.5 g/L photo-catalyst at pH 3. The reusability test shows that the photo-catalytic activity is retained excellently due to change in chemical nature of the catalyst from α -Bi2O3 to ß-Bi2O3, Bi2O2CO3 and BiOCl. A suitable mechanism is proposed.

Size-Dependent Catalytic Activity and Fate of Palladium Nanoparticles in Suzuki-Miyaura Coupling Reactions.

Stable, catalytically active palladium nanoparticles of various average diameters (1.9-7.4 nm) have been synthesized and characterized by X-ray diffraction, spectroscopy, and microscopy techniques to demonstrate remarkable size-dependent and renewed catalytic activity toward the Suzuki-Miyaura coupling reaction in green protocol. The catalytic activity is found to depend on the amount of the reducing agent, stabilizer-precursor ratio, solvent composition, and aryl halides used. The product obtained by this reaction is characterized by 1H NMR, 13C NMR, and IR spectroscopy analyses. A newly developed kinetic equation illustrates that while the catalyst particles of the lowest dimension are gradually exposed to the reactants and hence activated due to partial removal of capping polymer from the catalyst surface, others are deactivated due to agglomeration during the progress of the reaction, as conformed by the microscopic profiles of the used and unused catalysts.

Oral Ondansetron in Management of Dehydrating Diarrhea with Vomiting in Children Aged 3 Months to 5 Years: A Randomized Controlled Trial.

OBJECTIVES: To evaluate the role of oral ondansetron in facilitating successful rehydration of under-5-year-old children suffering from acute diarrhea with vomiting and some dehydration. STUDY DESIGN: Children (n = 170) aged 3 months to 5 years with acute diarrhea with vomiting and some dehydration were enrolled in this double blind, randomized, placebo-controlled trial. The participants were randomized to receive either single dose of oral ondansetron (n = 85) or placebo (n = 85) in addition to standard management of dehydration according to World Health Organization guidelines. Failure of oral rehydration therapy (ORT), administration of unscheduled intravenous fluids, and amount of oral rehydration solution intake in 4 hours were the primary outcomes. Secondary outcome measures included duration of dehydration correction, number of vomiting episodes, adverse effects, and caregiver satisfaction. RESULTS: Failure of ORT was significantly less in children receiving ondansetron compared with those receiving placebo (31% vs 62%; P < .001; relative risk 0.50, 95% CI 0.35-0.72). Almost one-half of the children in the ondansetron group received intravenous fluids compared with those in the placebo group, but it was not statistically significant (P = .074; relative risk 0.56, 95% CI 0.30-1.07). The oral rehydration solution consumption was significantly more in the ondansetron group (645 mL vs 554 mL; mean difference 91 mL; 95% CI: 35-148 mL). Patients in the ondansetron group also showed faster rehydration, lesser number of vomiting episodes, and better caregiver satisfaction. CONCLUSION: A single oral dose of ondansetron, given before starting ORT to children <5 years of age with acute diarrhea and vomiting results in better oral rehydration. TRIAL REGISTRATION: Clinical Trial Registry of India: CTRI-2011/07/001916.

Topical Corticosteroid Misuse: The Scenario in Patients Attending a Tertiary Care Hospital in New Delhi.

INTRODUCTION: Irrational use of Topical Corticosteroid (TC) is quite common in India due to unrestricted availability and use of TC not only by general public but also by physicians and chemists due to quick relief of symptoms in different dermatological conditions. AIM: The present study was conducted to evaluate and analyse the prevalence of misuse of TC and the causes behind misuse of TC among patients in a dermatology outpatient department in New Delhi. MATERIALS AND METHODS: This was a cross-sectional observational questionnaire based study conducted over a period of 5 months (1st June 2015 to 30th November 2015). Patients were questioned and assessed for misuse of TCs in terms of indication, dose, frequency, duration and source of recommendation of TC. RESULTS: During the study period, 256 (11.77%) patients presented with inappropriate use of TC out of 2174 patients attending OPD of dermatology unit of a government hospital. A total of 250 patients presented with adverse effects of TC resulting from the misuse of these drugs. There were 60%female patients and 20-29 years (38%) was the most common age group affected. We found fungal infection (38%) was the most common reason of abuse followed by facial acne (29%) and lightening of skin colour (8.4%). Friends and family (33.2%) were found to be the most influencing factors for misuse of TC. Betamethasone (72.8%) was the most commonly used TC preparation and tinea incognito (26.4%) followed by facial acne (25.6%) were the most common side effect experienced. CONCLUSION: Outcome of the misuse of TC could be dreadful and the cause for same lies at all levels- patients, family, physicians and the regulatory authorities.

Atorvastatin prevents type 2 diabetes mellitus--an experimental study.

Recent reports of increased diabetes risk have raised concerns regarding the use of statins. The present study was therefore planned to clarify whether atorvastatin can prevent diabetes development in a rat model of type 2 diabetes mellitus. Eight week old male Wistar rats were randomized into three groups (n = 12 each group). Group A was given standard chow diet, while group B and group C were offered high sucrose diet. In addition to high sucrose diet, group C was given atorvastatin (20mg/kg/day) from beginning of study till 26th week. After 26 weeks, a low dose of streptozotocin (15 mg/kg, i.p.) was given to all 3 groups and further followed for 4 weeks. Oral glucose tolerance tests were done at week 4, 26 and week 30. Development of impaired glucose tolerance at week 26 (16.66% vs 100%, P = <0.001) and diabetes at week 30 (16.66% vs 81.81%, P = 0.002) was significantly lower in rats pretreated with atorvastatin along with high sucrose diet viz group C compared to group B rats who received high sucrose diet only respectively. Also, metabolic indices like body weight, hypertriglyceridemia, glucose area under the curve (Gl-AUC) were significantly lower in group C compared to group B (P = <0.05) while insulin resistance (HOMA-IR) was also lower in group C (P = 0.05). This study clearly demonstrates for the first time in a rat model of type 2 diabetes mellitus that atorvastatin prevents development of type 2 diabetes.

Polymorphonuclear leukocyte function in type-2 diabetes mellitus patients and its correlation with glycaemic control.

Infection is an important cause of morbidity and mortality in diabetic patients. Chronic hyperglycaemia impairs host defense mechanism such as cell mediated immunity, polymorphonuclear leukocyte (PMNL) function, antibody formation etc. PMNL serves as bodies first line of defense against various infections. The present study was undertaken to establish a correlation between impaired PMNL function, blood glucose levels and its improvement with good glycaemic control with glibenclamide and glimepiride, with special reference to parameters such as respiratory burst and O2(-) and H2O2 production by diabetic neutrophils.

Drug dose calculation need to be drilled.

A study was conducted to establish the knowledge of correct dose calculations and conversion between mass concentration, dilution and percentage concentrations amongst medical and paramedical personnel handling patient, with life saving support system. A questionnaire was prepared having five standard questions to be answered in ten minutes by medical house officers and nurses. Results of the study suggested that the knowledge of correct dose calculations of both the medical and paramedical personnel needs to be improved to impart best possible management to the critically ill patients.

Current status of prophylactic use of antimicrobial agents for caesarean section in a tertiary care teaching hospital in eastern Nepal.

A prospective assessment of the current status of prophylactic use of antimicrobial agents (AMAs) for caesarean section deliveries at BPKIHS, Dharan, Nepal was done. Data was collected by systemic random sampling of 349 in patient case sheets. The prevalence of use of ampicillin either alone or in combination with metronidazole was noted in both the elective and non-elective groups, either in the hospital or at discharge, while only 7.0-9.0% of patients receivedAMAs other than ampicillin. Ampicillin has been reported to be an effective AMA in reducing post-partum endometritis and our observation also corroborates with this finding.