A comparative study of essential oils of Cymbopogon citratus and some members of the genus Citrus

Steam distilled oils of some species of the genus Citrus and Cymbopogon citratus were analyzed by GC-MS. It is observed that citral b was the most common constituent of the oils, which could be a good inhibitor of beta-glucuronidase as all the tested essential oils showed significant inhibition of beta-glucuronidase. IC50 values of a mixture of citral a and b also proved the hypothesis. The same oils also exhibited positive response against tested microbes.     

Spectrophotometric determination of nitrogen in small quantities of biological materials

Summary A new spot test for ammonium, by its reaction with ruthenium trichloride-triphenylphosphine, having a Ig limit of identification is reported. On the basis of this spot reaction a spectrophotometric method is described for the determination of minute quantities of NH₄-N from biological materials.

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Zusammenfassung Eine neue Tüpfelreaktion auf Ammonium wurde beschrieben, die auf der Umsetzung mit Rutheniumtrichlorid-Triphenylphosphin beruht. Die Erfassungsgrenze beträgt 1g. Mit Hilfe dieser Reaktion lassen sich kleinste Mengen Ammoniumstickstoff spektrophotometrisch in biologischem Material bestimmen.

     

Synthesis of novel 6-substituted sulfur-containing derivatives of pyridoxine

An efficient synthesis of novel 6-substituted derivatives of pyridoxine was achieved. The reactions of various thiols with mono-, bis-, and tris(сhlorine) derivatives of 6-methyl-2,3,4-tris(hydroxymethyl)pyridin-5-ol (6-hydroxymethylpyridoxine) gave sulfur-containing derivatives of pyridoxine.     

Linear Invariants of a Cartesian Tensor Under SO(2), SO(3) and SO(4)

A general theory for finding the invariants of an arbitrary tensor is described. Group theoretic methods produce formulas which precisely determine the number of invariants for a Cartesian tensor of arbitrary rank defined over a space of dimension 2,3 or 4. Explicit expressions are obtained for simple cases.     

Simultaneous sensing system for identical long-period gratings sensors using subcarrier multiplexing

A novel system based on subcarrier multiplexing is presented for simultaneous sensing of identical long-period grating sensor array. The experimental results show that the system facilitates excellent discrimination of two sensors at identical resonance wavelength.     

Electrochemical,morphological, and spectroscopic study of poly(aniline-co-<Emphasis Type="Italic">o</Emphasis>-bromoaniline) (PA-co-<Emphasis Type="Italic">o</Emphasis>-BrA) conducting copolymer

A series of moderately conducting and soluble copolymers of poly(aniline-co-o-bromoaniline) (PA-co-o-BrA) having different compositions was obtained by in the situ copolymerization method using different concentrations of monomer units of aniline and o-bromoaniline in the feed. The physio-chemical properties of the copolymers have been studied with sophisticated instrumental techniques. The electrochemical study of the copolymers was conducted by cyclic voltammetry. The band gap of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the copolymers was evaluated by UV-vis spectroscopy. The morphological study was conducted by scanning electron microscopy and transmission electron microscopy at high magnification which shows non-uniform tubular to globular morphology of the copolymers. Surface profiles of the polymers were studied by AFM analyses, and it has confirmed the smooth surface of the copolymers while the homopolymers possesses non-uniform surfaces. The particle size distribution curve indicates that the particle sizes vary in the range of 5 to 9000 nm, and a small fraction of particles possess a size in the range of 5–10 nm.     

Investigations of half-metallic ferromagnetism and thermoelectric properties of cubic XCrO3 (X = Ca,Sr,Ba) compounds via first-principles approaches

In this paper, the physical aspects of the cubic phase XCrO₃ ($\mathrm{X}=\mathrm{Ca},\mathrm{Sr},\mathrm{Ba}$) perovskites are studied by employing full-potential linearized augmented plane wave plus local orbital ($\text{FP-LAPW}+\mathit{lo}$) method. These compounds have been found stable in ferromagnetic (FM) phase since they possess lower energy in FM phase compared to non-FM phase and their stability is also confirmed by calculating the enthalpy of formation (ΔH). The electronic structures of these compounds are analyzed with Trans and Blaha modified Becke–Johnson potential (TB-mBJ) for both spin up and spin down channels, which indicate their half-metallic characters. Analysis of density of states (DOS) shows major contributions of O-2p states in the valence band and Cr 3d-state in conduction band. A comparative analysis of crystal field effect ($\mathrm{\Delta }{\mathrm{E}}_{\mathrm{crystal}}$) and the exchange energies (direct ${\mathrm{\Delta }}_x(d)$ and indirect ${\mathrm{\Delta }}_x(pd)$) tells about the main part of electronic spin in ferromagnetic character. The calculated magnetic moments make these compounds favorable for spintronic applications. In the end, thermoelectric parameters are computed for 200 K–800 K temperature range to explore potential of these compounds for applications in renewable energy devices.     

A Brief Review on Fluorescent Copper Sensor Based on Conjugated Organic Dyes

The design and development of the fluorescence reporting molecules for the trace recognition of the metallic ions in the aqueous, mixed organic aqueous media, environmental specimen, living things e.g., body fluids, serum, urine etc is the evergreen research area. Among several methodologies utilized for these purposes, the fluorescent techniques have wonderful impact in the era of metal sensor development due to their acclamatory features of non-invasive detection process and appreciable sensitivity. The utilization of small organic molecules for the sensation of metallic ions through the fluorescent techniques harvested the wonderful results having some interesting features of chromogenic response on metal binding, robustness in the preparation and applicability to establish the metallic accumulation level inside the live cells via bioimaging studies. The detailed knowledge and background about the several reported chemosening strategies have the utmost importance in order to understand or to design the novel molecules for metal sensing purposes. The objective of the presents review was to compile the best ever used copper sensing strategies via fluorescent means in the running decade. We have summarized the values of optical positions of the spectral lines, spectral shifting upon metal binding, binding/association/dissociation constants, chromogenic changes in the reaction mixture, proposed complexation mechanism of the ligand with the copper, ligand sensitivities toward the copper recognition, binding stoichiometries and the detailed bioimaging results where applicable.     

Lamp-assisted CVD of carbon micro/nano-structures using metal catalysts and CH2I2 precursor

Carbon micro/nanofibers and nanotubes were deposited via chemical vapor deposition (CVD) using CH₂I₂ precursor and different metal catalysts (Pd, Ni, Fe, Co and Mn) on Si (1 0 0) substrates. A versatile and low-cost IR lamp technique is employed to induce the deposition process. With this method carbon features could be obtained already at temperatures much lower than with common techniques. Palladium metal was deposited by laser-assisted CVD from a liquid solution of the ammine complex and the 3d metals by thermal evaporation. Large-scale periodicity of nano-sized metal catalysts, and subsequently of carbon deposits was obtained by using monolayers of polystyrene microspheres as mask. The carbon structures were analyzed by SEM and micro-Raman spectroscopy.