Studies on non-cyanide alkaline zinc electrolytes

An alkaline non-cyanide zinc plating solution consisting of 10 g/l zinc oxide, 90 g/l sodium hydroxide and 1.5 g/l gelatine was prepared . Using this solution, a smooth, uniform and fine-grained semi-bright deposit was obtained on mild steel sheets over a wide range of current density and pH at 303 K. The plating bath had about 63% current efficiency and 25% throwing power at 303 K and at pH 10. Caffeine and vanillin additions to this bath gave bright zinc deposits. Received: 30 January 1998 / Accepted: 15 May 1998     

An end-point global gradient weighted estimate for quasilinear equations in non-smooth domains

A weighted norm inequality involving A₁ weights is obtained at the natural exponent for gradients of solutions to quasilinear elliptic equations in Reifenberg flat domains. Certain gradient estimates in Lorentz–Morrey spaces below the natural exponent are also obtained as a consequence of our analysis.     

Electrochemical Synthesis of β‐Cyclodextrin Functionalized Silver Nanoparticles and Reduced Graphene Oxide Composite for the Determination of Hydrazine

β‐cyclodextrin (β‐CD) functionalized silver nanoparticles (AgNPs) and reduced graphene oxide (RGO) via one step electrochemical potentiodyanamic method has been prepared. Scanning electron microscopy, Energy‐Dispersive X‐ray spectroscopy, electrochemical impedance spectroscopy and cyclic voltammetry were used to study the role of β‐CD on preparation of AgNPs and RGO. RGO/β‐CD/AgNPs modified GCE showed good electrochemical activity towards electro‐oxidation of hydrazine in terms of decreasing the over potential and increasing the peak current. The kinetic parameters such as electron transfer coefficient (α) and diffusion coefficient (Do) of the modified electrode towards hydrazine were determined to be 0.66 and 0.97×10^?6 cm² s^?1, respectively. The LOD of our sensor was many folds lower than that of recommended concentration of hydrazine in drinking water by United States Environmental Protection Agency and World Health Organization. The sensor exhibited a wide linear range from 0.08 to 1110 µM and a very low detection limit (LOD) of 1.4 nM. In addition, the sensor selectively determined hydrazine even in the presence of common interferents.     

Cis–trans isomerism shown by the polymer containing chalcone moiety in its side chain

Polymer containing chalcone moiety showed a cis–trans isomerism. Two novel acrylate monomers, 4‐[3‐(2,4‐dichloro‐phenyl)3‐oxoprop‐1‐en‐1‐yl]phenylacrylate (DCP) and 4‐(3‐(4‐((4‐(4‐(3‐(2,4‐dichlorophenyl)‐3‐oxoprop‐1‐en‐1‐yl)phenoxy)‐6‐((4‐nitrophenyl)amino)‐1,3,5‐triazin‐2‐yl)oxy)phenyl)‐3‐oxoprop‐1‐en‐1‐yl)phenyl acrylate (TCP) were synthesized and copolymer with acrylic acid. All the monomers and polymer were characterized by IR, NMR and UV techniques. The M_w of the DCP based polymer and TCP based polymer were 4000 and 10,000 g/mol respectively. DCP and TCP based polymer showed double stage and single stage decomposition respectively. The reactivity ratio of the polymers showed that the poly(DCP‐co‐AA) formed random polymerization whereas poly(TCP‐co‐AA) formed alternate copolymerization. The poly(TCP‐co‐AA) showed excellent photoisomerism whereas poly(DCP‐co‐AA) showed photocycloaddition reaction. Copyright © 2016 John Wiley & Sons, Ltd.     

Three‐Arm,Biotin‐Tagged Carbazole–Dicyanovinyl–Chlorambucil Conjugate: Simultaneous Tumor Targeting,Sensing, and Photoresponsive Anticancer Drug Delivery

The design, synthesis, and in vitro biological studies of a biotin–carbazole–dicyanovinyl–chlorambucil conjugate (Bio‐CBZ‐DCV‐CBL; 6 ) are reported. This conjugate ( 6 ) is a multifunctional single‐molecule appliance composed of a thiol‐sensor DCV functionality, a CBZ‐derived phototrigger as well as fluorescent reporter, and CBL as the anticancer drug, and Bio as the cancer‐targeting ligand. In conjugate 6 , the DCV bond undergoes a thiol–ene click reaction at pH<7 with intracellular thiols, thereby shutting down internal charge transfer between the donor CBZ and acceptor DCV units, resulting in a change of the fluorescence color from green to blue, and thereby, sensing the tumor microenvironment. Subsequent photoirradiation results in release of the anticancer drug CBL in a controlled manner.     

Mycothiol disulfide reductase: solid phase synthesis and evaluation of alternative substrate analogues

A solid phase synthesis of des-myo-inositol mycothiol disulfide and its alpha-configured methyl- and benzyl-glycoside derivatives has been developed. Kinetic characterisation of these compounds has demonstrated their viability as alternative substrates for use in mycothiol disulfide reductase enzyme assays.     

Enhancement in the supercapacitive storage performance of MnCO<Subscript>3</Subscript> using SiO<Subscript>x</Subscript> nanofluid-based electrolyte

Generally adopted strategies to improve capacitance of the electrode materials are tuning various properties of the electrode material or increasing the cell voltage. While tuning the properties of the electrode material is tedious, increasing the cell voltage is restricted by the stability of the electrolyte. Herein, we report a facile approach to improve the capacitance of MnCO₃ by the influence of SiO_x nanofluid in the electrolyte. The capacitance properties of MnCO₃ are studied in 0.1 M Mg(ClO₄)₂ electrolyte in the presence and in the absence of SiO_x nanofluid. The presence of small amount of SiO_x nanofluid in the electrolyte provides higher diffusivity and more conductive percolation paths for ions and thus decreases internal resistance and increases ionic conductivity of the electrolyte. As a result, 60% enhancement in the capacitance is witnessed for MnCO₃. Further, nanofluid containing electrolyte is found to be stable over a month.

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Graphical abstract Improvement in the capacitance properties of MnCO by the influence of SiO nanofluid

     

Amberlyst-15 catalyzed synthesis of novel thiophene–pyrazoline derivatives: spectral and crystallographic characterization and anti-inflammatory and antimicrobial evaluation

Increasing instances of antimicrobial drug resistance and Inflammation-mediated disorders requires the design and synthesis of new small-molecules with higher affinity and specificity for their potential targets to serve as antibiotics or anti-inflammatory drugs, respectively. The current study presents the synthesis of a series of chalcones, 3(a–h) by the reaction of 3-methylthiophene-2-carbaldehyde, 1 and acetophenones, 2(a–h) by Claisen–Schmidt approach. The chalcones were efficiently transformed into thienyl-pyrazolines, 5(a–h) by their reaction with thiosemicarbazide hydrochloride, 4 in the presence of Amberlyst-15 as a catalyst in acetonitrile at room temperature. Alternatively, the compounds 5(a–h) were prepared by conventional method using acetic acid (40%) medium. Structures were characterized by spectral and single crystal X-ray diffraction studies. Preliminary assessment of the anti-inflammatory properties of the compounds showed that, amongst the series, compounds 5b and 5c have excellent anti-inflammatory activities. Further, compound 5c showed excellent activity against Escherichia coli (MIC, 15 µg/mL), Bacillus subtilis (MIC, 20 µg/mL), Aspergillus niger (MIC, 20 µg/mL), and Aspergillus flavus (MIC 15 µg/mL), respectively. Compounds 5a and 5b were also found to be active against the tested microorganisms.