Production of Mycophenolic Acid by <Emphasis Type="Italic">Penicillium brevicompactum</Emphasis> Using Solid State Fermentation

Solid-state fermentation using the microfungus Penicillium brevicompactum for the production of mycophenolic acid is reported in this paper. Of the initial substrates tested (whole wheat, cracked wheat, long grain Basmati rice, and short grain Parmal rice), Parmal rice proved to be the best. Under initial conditions, using steamed Parmal rice with 80% (w/w) initial moisture content, a maximum mycophenolic acid concentration of 3.4 g/kg substrate was achieved in 12 days of fermentation at 25 °C. The above substrate was supplemented with the following additional nutrients (g/L packed substrate): glucose 40.0, peptone 54.0, KH₂PO₄ 8.0, MgSO4?7H₂O 2.0, glycine 7.0, and methionine 1.65 (initial pH 5.0). A small amount of a specified trace element solution was also added. The final mycophenolic acid concentration was increased to nearly 4 g/kg substrate by replacing glucose with molasses. Replacing Parmal rice with rice bran as substrate further improved the mycophenolic acid production to nearly 4.5 g/kg substrate.     

Optimisation of chromium doping in LiNbO3 single crystals

Growth of undoped and Cr doped (0.1, 0.25 and 0.5 mol % Cr₂O₃) congruently‐ melting‐composition LiNbO₃ single crystals by Czochralski technique is reported. Chromium doping was optimised to get crystals with potential for an integrated, broadband, tunable laser in the 700‐1100 nm spectral range. Typical sizes of the grown crystals are 25‐30 mm in diameter and 30‐40 mm in length. Symmetrical and sharp conoscopy pictures confirm the optical homogeneity of the crystals. Optical transmission was recorded for both undoped and doped crystals. 70% transmittance was observed. The grown crystals have reasonably good laser damage threshold. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Voltammetric Immunoassay for the Detection of Protein Biomarkers

A strategy for a fast (ca. 20 min), specific, electrochemical immunoassay for the cardiac biomarker creatine kinase (CK) and the human cytokine interleukin 10 (IL10) has been developed in this paper. The polyaniline modified gold surface formed from electrochemical reduction of diazonium salt supplies a solid substrate to link the activated carboxylic acid groups from the antibodies, which were labelled with ferrocene. The direct electrochemistry of ferrocene allows the analysis of protein markers with good sensitivity. The creatine kinase sensor demonstrates limit of detection of 0.5 pg mL^?1 in a physiological Krebs‐Henseleit solution. The anti‐IL10 antibody retained fluorescence activity after further coupling to ferrocene and covalent immobilization on to a gold electrode, showing a linear detection range for IL‐10 from 0.001 ng mL^?1 to 50 ng mL^?1 in PBS. We attribute the high sensitivity to the well‐controlled modified surface which results in end–on antibodies that can specifically capture the antigen with ease.     

Electrochemical and oxygen reduction properties of pristine and nitrogen-doped few layered graphene nanoflakes (FLGs)

Vertically aligned few layered graphene (FLGs) nanoflakes were synthesized by microwave plasma deposition for various time durations ranging from 30 to 600 s to yield graphene films of varying morphology, microstructure and areal/edge density. Their intrinsic electrochemical properties were explored using Fe(CN)₆ ^3?/4? and Ru(NH₃)₆ ^3+/2+ redox species. All the FLG electrodes demonstrate fast electron transfer kinetics with near ideal ΔEp values of 60–65 mV. Using a relationship between electron transfer rate and edge plane density, an estimation of the edge plane density was carried out which revealed a moderation of edge plane density with increase in growth time. The pristine FLGs also possess excellent electrocatalytic activity towards oxygen reduction reaction (ORR) in alkaline solutions. This ORR activity can be further enhanced by exposing the pristine FLGs to nitrogen electron cyclotron resonance plasma. The metal free N-doped FLGs exhibit much higher electrocatalytic activity towards ORR than pristine FLGs with higher durability and selectivity than Pt-based catalysts. The excellent electrochemical performance of N-doped FLGs is explained in terms of enhanced edge plane exposure, high content of pyridinic nitrogen and an increase in the electronic density of states.     

A one-pot multicomponent Biginelli reaction for the preparation of novel pyrimidinthione derivatives as antimicrobial agents

A convenient synthesis of pyrimidinthiones was carried out in presence of thiourea and easily available catalyst sulfamic acid ( 2a-t) . One-pot Biginelli reaction is very important due to the use of simple and readily available chemicals, less reaction time, economically friendly, and furnishing good yield. Structures of the synthesized compounds are characterized by spectral techniques like IR, ¹H-NMR, ¹³C-NMR, and LC–MS. Synthesized compounds were studied for their antimicrobial activity against several strains of bacteria (E. coli, P. aeruginosa, and S. aureus, S. pyogenes) and fungi (C. albicans, A. niger, and A. clavatus) using serial dilution method.     

Dipolar-glass-like behaviour of 0.7PMN-0.3PZ ceramic

Relaxor ferroelectric behaviour has been observed for lead magnesium niobate-lead zirconate (0.7PMN-0.3PZ) ceramic. The freezing temperature obtained from fitting of dielectric data to the Vogel-Fulcher equation is very close to the dielectric-maximum temperature and to the temperature of collapse of remanant polarization. The temperature dependence of the spontaneous polarization follows a modified Neel's equation. Specific-heat measurement shows canonical glass-like behaviour, and the value of the glass-transition temperature is very close to the freezing temperature obtained from the Vogel-Fulcher equation. All the observations together indicate that 0.7PMN-0.3PZ ceramic behaves like a dipolar glass.     

Electron beam irradiation-induced transformations in the electrical properties of 4’-octyl-4-cyanobiphenyl (8CB)

Changes in the dielectric and thermodynamical properties of electron beam-irradiated 4′-octyl-4-cyanobiphenyl (8CB) were studied. Irradiation-induced changes in the phase transition temperature, dielectric anisotropy, relaxation frequency and activation energy of an observed non-collective relaxation mode corresponding to molecular rotation about the short axis were determined in both nematic and smectic A_d phases. In the nematic phase, dielectric anisotropy increased for a small dose but decreased for a relatively high dose, whereas the relaxation frequency increased due to the irradiation. The pure and irradiated samples were characterised by UV–visible spectroscopy, Fourier transform infrared spectroscopy, gas chromatography, gas chromatography coupled with mass spectroscopy and pulse radiolysis. The observed changes in the dielectric parameters are related to the detachment of the CN group from some of the 8CB molecules due to the electron beam irradiation.     

Shape-memory effect in PMN-PT(65/35) ceramic

We report the observation of fairly large and fully recoverable shape-memory strain in thin bars of lead magnesium niobate lead titanate ceramic for a composition (65/35) near its morphotropic phase-boundary. The recoverable shape strain produced by bending and thermal-cycling experiments is ∼0.3%, similar in magnitude to that reported for the shape-memory effect (SME) observed in some other dielectric ceramics. An explanation of the observed SME and the recoverable shape-strain is given in terms of the ferroelastic phase transitions, and the availability of a large number of competing phases and domain states near the morphotropic phase boundary in this material. The stress-induced shifting of the temperatures at which the ferroelastic phase transitions occur also plays an important role in ensuring good crystallographic reversibility around the thermal-cycling experiments.     

Syntheses,X-ray structures,electrochemical properties and biological evaluation of mono- and dinuclear N2O2-donor ligand-Fe systems

Transition Metal Chemistry - The present work reports the synthesis, spectroscopic and structural characterizations of Fe(III) complexes of types [Fe(L)(H2O)(NCS)] (1),...