Synthesis of Copper Metal Organic Framework Based on Schiff Base Tricarboxylate Ligand for Highly Selective and Sensitive Detection of 2,4,6-Trinitrophenol in Aqueous Medium

Journal of Fluorescence - By using Schiff base tricarboxylate ligand 5-(4-carboxybenzylideneamino)isophthalic acid (H3CIP), a new imine functionalized copper metal organic framework (MOF) has been...     

Chemoselective Oxidation of Benzylic Alcohols with Solid Supported CrO3/TBHP Under Microwave Irradiation

The efficient use of microwave energy coupled with dry media technique for the oxidation of benzylic alcohols using catalytic CrO₃ and TBHP has been effectively projected     

Study of the amplification characteristics of a coaxial EDF with varying coupling conditions

A coaxial erbium doped fiber (EDF) designed to show inherent gain flattening for one of its propagating modes in general supports two or more modes with different gains. In this paper, we show that when such an amplifying coaxial EDF is spliced to a single mode transmission fiber carrying the signal, in general, more than one mode is excited each with its excitation coefficient strongly dependent on wavelength. Due to the interference between these modes, the amplified output coupled to an output single core transmission fiber can be a very sensitive function of the coaxial EDF length, especially around the phase matching wavelength (PMW), and does not show inherent gain flattening. However, due to interference between the two modes, the coaxial fiber acts as a band reject filter at the phase matching wavelength with attenuation and bandwidth depending on fiber parameters. This property can be employed for inherent gain flattening when both modes are excited.     

Study of enhanced red emission from Sm(Sal)3Phen ternary complexes in Poly Vinyl Alcohol film

In the present work, dinuclear complexes of salicylic acid (Sal) and 1,10-phenanthroline (Phen) were synthesized with different concentrations of Samarium ion (Sm³⁺) in Poly Vinyl Alcohol (PVA) polymer films and their structural and spectroscopic properties were investigated. Judd-Ofelt theory has been employed to estimate the several radiative parameters for SmCl₃ and Sm(Sal)₃Phen complex in PVA polymer film which are in fairly agreement between the experimental and the theoretical values supporting the J-O theory. Photoluminescence properties of the complex have been studied on 355 nm and 400 nm excitations in steady state as well as in time domain. On the basis of the UV-Vis absorption, FT-IR absorption, excitation, emission spectra and decay curves, spectroscopic properties of these films were studied and the photophysics involved was explained in terms of energy transfer and the RE encapsulation effect.     

Simple Strategy of Repeated Batch Cultivation for Enhanced Production of 1,3-Propanediol Using Clostridium diolis

Repeated batch cultivation (empty-and-fill protocol) using obligate anaerobe Clostridium diolis was attempted in the present study to improve the production of 1,3-propanediol (1,3-PD). In repeated batch operation, 20?% (v/v) culture broth was removed from the bioreactor and supplemented with an equal volume of fresh nutrient medium when the residual glycerol concentration in the bioreactor decreased below 15?g/L. Four cycles of culture broth withdrawal and subsequent replacement resulted in achieving a 1,3-PD concentration of 67.8?g/L with a productivity of 1.04?g/L/h at the end of 65?h. This represented a 1,3-PD concentration and productivity enhancement by 2.6-fold and 1.5-fold, respectively, as compared to batch 1,3-PD fermentation. This is the first report on the use of repeated batch mode of bioreactor operation for enhanced 1,3-PD production.     

Structure–property correlations in lead silicate glasses and crystalline phases

Lead silicate glasses containing 40–65?mol% of PbO were prepared at two melt-quenching rates and characterized by X-ray diffraction, UV-Visible absorption spectroscopy, density, microhardness, thermo-mechanical analysis, differential scanning calorimetry and Raman scattering studies. On increasing the PbO concentration, density increases, glass transition temperature decreases and the optical absorption edge shifts towards longer wavelength. An intense optical absorption band was observed just below the absorption edge in glasses with 55?mol% and higher concentration of PbO. Dilatometric measurements show an unusual property that glasses do not show any abrupt increase in volume near the glass transition temperature but transform directly into the liquid state. Raman spectroscopy confirmed that the concentration of SiO₄ tetrahedra containing one or more NBOs increase with PbO mol%. Devitrification studies on lead silicate glasses found that samples with 40–45?mol% of PbO do not crystallize, whereas samples with higher PbO concentration produce multiple crystalline phases like PbSiO₃, Pb₃₃Si₂₄O₈₁, Pb₂SiO₄ and Pb₃Si₂O₇ on heat treatment.     

Synthesis, characterization and study of arsenate adsorption from aqueous solution by α- and δ-phase manganese dioxide nanoadsorbents

Single-phase α-MnO₂ nanorods and δ-MnO₂ nano-fiber clumps were synthesized using manganese pentahydrate in an aqueous solution. These nanomaterials were characterized using the Transmission Electron Microscope (TEM), Field Emission Scanning Electron Microscope (FE-SEM), Powder X-ray diffraction (XRD) and the Brunauer-Elmet-Teller nitrogen adsorption technique (BET-N₂ adsorption). The structural analysis shows that α-MnO₂ (2×2 tunnel structure) has the form of needle-shaped nanorods and δ-MnO₂ (2D-layered structure) consists of fine needle-like fibers arranged in ball-like aggregates. Batch adsorption experiments were carried out to determine the effect of pH on adsorption kinetics and adsorption capacity for the removal of As(V) from aqueous solution onto these two types of nanoadsorbents. The adsorption capacity of As(V) was found to be highly pH dependent. The adsorption of As(V) onto α-MnO₂ reached equilibrium more rapidly with higher adsorption capacity compared to δ-MnO₂.     

Profiling Differential Expression of Cellulases and Metabolite Footprints in Aspergillus terreus

This study reports differential expression of endoglucanase (EG) and β-glucosidase (βG) isoforms of Aspergillus terreus. Expression of multiple isoforms was observed, in presence of different carbon sources and culture conditions, by activity staining of poly acrylamide gel electrophoresis gels. Maximal expression of four EG isoforms was observed in presence of rice straw (28 U/g DW substrate) and corn cobs (1.147 U/ml) under solid substrate and shake flask culture, respectively. Furthermore, the sequential induction of EG isoforms was found to be associated with the presence of distinct metabolites (monosaccharides/oligosaccharides) i.e., xylose (X), G₁, G₃ and G₄ as well as putative positional isomers (G₁/G₂, G₂/G₃) in the culture extracts sampled at different time intervals, indicating specific role of these metabolites in the sequential expression of multiple EGs. Addition of fructose and cellobiose to corn cobs containing medium during shake flask culture resulted in up-regulation of EG activity, whereas addition of mannitol, ethanol and glycerol selectively repressed the expression of three EG isoforms (Ia, Ic and Id). The observed regulation profile of βG isoforms was distinct when compared to EG isoforms, and addition of glucose, fructose, sucrose, cellobiose, mannitol and glycerol resulted in down-regulation of one or more of the four βG isoforms.     

Solid acid clay mediated copolymerization of methyl acrylate and 1‐octene: 2D NMR substantiation of predominant alternating comonomer sequence

Montmorillionite K10 powder presence during radically initiated copolymerization of methyl acrylate (M) and 1‐octene (O) gave copolymers with higher incorporation of alkene unit. Highly viscous and transparent copolymers showed alternation irrespective of the copolymer composition. Increasing the amount of K10 powder increased the total percentage conversion, as well as 1‐octene incorporation. The monomodal curves obtained in gel permeation chromatography (GPC) substantiated that true copolymers were formed. The alternation in the copolymers was authenticated through Heteronuclear Multiple Quantum Correlation (HMQC) experiments in conjugation with Total Correlated Spectroscopy (TOCSY). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2156–2162, 2009