Ag+ ion transport studies in a polyvinyl alcohol-based polymer electrolyte system

Thick films of pure polyvinyl alcohol and polyvinyl alcohol doped with silver nitrate with different compositions have been prepared by solution cast technique. The FT-IR spectrum confirms the complexation process. The conductivity of the pure polyvinyl alcohol is of the order of 10⁻⁷ Sm⁻¹ at 90 °C, and its value increases by two orders of magnitude when doped with 20 wt% of AgNO₃. The activation energy, calculated from the Arrhenius plot for all compositions of the poly vinyl alcohol doped with silver nitrate, is between 0.24 and 0.35 eV. The migration energy for the ion in polymer electrolyte has been calculated from the modulus spectrum, and is in good agreement with the activation energy calculated from the Arrhenius plot. The modulus spectra indicate the non-Debye nature of the material.     

Synthesis,anti‐inflammatory activity,and molecular docking study of novel azo bis antipyrine derivatives against cyclooxygenase‐2 enzyme

We have synthesized a new series of azo‐bis antipyrine derivatives from a one‐pot multicomponent Knoevenagel/Michael addition reaction of antipyrine, with a diversity of azo aldehydes in ethanol and L‐Proline as a catalyst under reflux condition. The anti‐inflammatory activity of the final products was assessed using the inhibition of albumin denaturation technique. Compound 3f showed an inhibitory effect with IC₅₀ values of 3.6 μM with respect to the standard anti‐inflammatory drug Aspirin, with IC₅₀ values of 2 μM. In addition, molecular docking was performed to confirm the in vitro results against the enzymatic inhibition activity of COX‐2 enzymes in which compound 3f showed good binding affinity with an inhibition constant (Ki) of 1.79 nM.     

Synthesis,anticancer evaluation,and docking studies of some novel azo chromene derivatives

We have described a simple, convenient, and high-yielding one-pot synthesis of novel azo chromene derivatives via a three-component reaction of various azo aldehydes with dimedone and malononitrile using 10 mol% of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as catalyst and ethanol as solvent at reflux condition. All the synthesized compounds have been characterized using Fourier-transform infrared spectroscopy (FT-IR), ¹H NMR, ¹³C NMR, and HR-MS spectra and molecular docking was performed to explore new inhibitors of human placental aromatase cytochrome P450 and cyclooxygenase-2 enzymes. Of all the compounds docked, compound (E)-2-amino-4-(4,4-dimethyl-2,6-dioxocyclohexyl)-6-((3-methoxyphenyl)diazenyl-4H-chromene-3-carbonitrile ( 4o ) showed good binding affinity with the active site of human placental aromatase cytochrome P450 enzyme (PDB: 3EQM) with inhibition constant (Ki) 1.66 nM and compound 4o also showed good binding affinity with the active site of cyclooxygenase-2 enzyme (PDB: 6COX) with inhibition constant (Ki) 367.17 pM. In vitro anti-cancer activity studies against MCF-7 cells were also performed for compounds 4o , anastrozole and celecoxib. Compound 4o showed an effective cytotoxicity at 19.8 μg/ml compared to anastrozole and celecoxib (24.7 and 26.2 μg/ml).     

Analysis of charge density and Fermi level of AlInSb/InSb single-gate high electron mobility transistor

A compact model is proposed to derive the charge density of the AlInSb/InSb HEMT devices by considering the variation of Fermi level, the first subband, the second subband and sheet carrier charge density with applied gate voltage. The proposed model considers the Fermi level dependence of charge density and vice versa. The analytical results generated by the proposed model are compared and they agree well with the experimental results. The developed model can be used to implement a physics based compact model for an InSb HEMT device in SPICE applications.     

Antibacterial Activity of Alpinia galanga (L) Willd Crude Extracts

Methanol, acetone and diethyl ether extracts of Alpinia galanga have been evaluated against pathogens viz. Bacillus subtilis MTCC 2391, Enterobacter aerogene, Enterobacter cloacae, Enterococcus faecalis, Escherichia coli MTCC 1563, Klebsiella pneumoniae, Pseudomonas aeruginosa MTCC 6642, Salmonella typhimurium, Staphylococcus aureus and Streptococcus epidermis using Agar well diffusion method. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of all the extracts were determined using the macrodilution method. Methanol extracts have shown excellent activity towards all the pathogens with MIC and MBC values ranging from 0.04–1.28 mg/ml and 0.08–2.56 mg/ml, respectively. The GC–MS analysis of methanol extracts have yielded compounds like 5-hydroxymethyl furfural (59.9%), benzyl alcohol (57.6%), 1,8 cineole (15.65%), methylcinnamate (9.4%), 3-phenyl-2-butanone (8.5%) and 1,2 benzenedicarboxylic acid (8.9%), which could be responsible for its broad spectrum activity. So, A. galanga can be quite resourceful for the development of new generation drugs.     

ABSORPTION MAXIMA OF CATIONS RELATED TO RETINAL AND THEIR IMPLICATION TO MECHANISMS FOR BATHOCHROMIC SHIFT IN VISUAL PIGMENT*

Abstract— The cations resulting from eleven retinal-related polyenes by placing the latter in n-butanol-sulfuric acid were examined spectroscopically in an effort to explain the batho-chromic effect observed in visual pigments. A comparison of the Λ_max values, intensities and 1/2-band widths of the model carbonium ions with those of the visual pigments does not seem to justify the representation of the chromophore in visual pigments as a pure carbonium ion.     

A Novel T-Connected Autotransformer-Based 18-Pulse AC–DC Converter for Harmonic Mitigation in Adjustable-Speed Induction-Motor Drives

This paper presents the design, analysis, and development of a novel autotransformer-based 18-pulse AC-DC converter with reduced kilovoltampere rating, feeding vector-controlled induction-motor drives (VCIMDs) for power-quality improvement at the point of common coupling (PCC). The proposed autotransformer consists of only two single-phase transformers for its realization against three single-phase transformers required in other configurations. The proposed 18-pulse AC-DC converter is suitable for retrofit applications, where, presently, a six-pulse diode bridge rectifier is being used. A set of power-quality parameters, such as total harmonic distortion (THD) and crest factor of AC mains current, power factor, displacement factor, and distortion factor at AC mains, THD of supply voltage at PCC, and DC-bus-voltage ripple factor for a VCIMD fed from an 18-pulse AC-DC converter, are computed to observe its performance. The presented design technique provides flexibility to give an average DC output from the proposed converter, which is the same as that of a conventional three-phase diode bridge rectifier. However, it is also possible to step-up or step-down the output voltage as required. The effect of load variation on VCIMD is also studied to observe the effectiveness of the proposed harmonic mitigator. A laboratory prototype of the proposed autotransformer-based 18-pulse AC-DC converter is developed to validate the design and simulation model.     

Quantum dot capped magnetite nanorings as high performance nanoprobe for multiphoton fluorescence and magnetic resonance imaging

In the present study, quantum dot (QD) capped magnetite nanorings (NRs) with a high luminescence and magnetic vortex core have been successfully developed as a new class of magnetic-fluorescent nanoprobe. Through electrostatic interaction, cationic polyethylenimine (PEI) capped QD have been firmly graft into negatively charged magnetite NRs modified with citric acid on the surface. The obtained biocompatible multicolor QD capped magnetite NRs exhibit a much stronger magnetic resonance (MR) T2* effect where the r2* relaxivity and r2*/r1 ratio are 4 times and 110 times respectively larger than those of a commercial superparamagnetic iron oxide. The multiphoton fluorescence imaging and cell uptake of QD capped magnetite NRs are also demonstrated using MGH bladder cancer cells. In particular, these QD capped magnetite NRs can escape from endosomes and be released into the cytoplasm. The obtained results from these exploratory experiments suggest that the cell-penetrating QD capped magnetite NRs could be an excellent dual-modality nanoprobe for intracellular imaging and therapeutic applications. This work has shown great potential of the magnetic vortex core based multifunctional nanoparticle as a high performance nanoprobe for biomedical applications.     

Synthesis of N‐Arylated 1,2‐Dihydroheteroaromatics Through the Three‐Component Reaction of Arynes with N‐Heteroaromatics and Terminal Alkynes or Ketones

The reaction of benzynes with N‐heteroaromatics including quinolines, isoquinolines, and pyridines and various terminal alkynes or ketones with an α‐hydrogen in the presence of KF and 18‐crown‐6 in THF at room temperature for 8 h gave various N‐arylated 1,2‐dihydroheteroaromatics in good to moderate yields. Some of these product structures are found in various naturally occurring and biologically active heterocyclic compounds. The reaction involves an unusual multiple construction of new C? C, C? N, and C? H bonds and the cleavage of a C? H bond in one pot. It is likely that the three‐component coupling proceeds through the nucleophilic addition of quinoline to benzyne, which generates a zwitterionic species. The latter then attracts a proton from terminal alkyne (or ketone) to generate an N‐arylated quinolinium cation and an acetylide anion. Further reaction of these two ions provides the final substituted 1,2‐dihydroquinolines. In the reaction, the terminal alkyne acts first as a proton donor and then as a nucleophile. The application of a three‐component coupling reaction product, 1,2‐dihydro‐2‐pyridinyl alkyne in a stereospecific [4+2] Diels–Alder cycloaddition reaction with N‐phenyl maleimide to give an isoquinuclidine derivative, an important core present in various natural products, is demonstrated.