A novel sheet 4f-3d mixed-metal pyridine dicarboxylate: synthesis, structure, photophysical properties and its transformation to a perovskite oxide

The synthesis, characterization and photophysical properties of a 4f-3d mixed metal compound, Gd(H2O)(3)Co[C5N1H3-(COO)(2)](3), are described; the structure is unique, consisting of sheets with large pores ( ca. 7 angstrom diameter) in the sheets and transforms to a perovskite oxide at moderate temperatures.

Structure of abnormal products isolated from the isomerization of 7-methoxychromano3,4-disoxazole - A novel synthesis of one of the products

A one-step synthesis of (IIb), an isomerization product of 7-methoxychromano3,4-disoxazole, from (III) is reported.

Novel insertion and deletion mutants of RpoB that render Mycobacterium smegmatis RNA polymerase resistant to rifampicin-mediated inhibition of transcription

The startling increase in the occurrence of rifampicin (Rif) resistance in the clinical isolates of Mycobacterium tuberculosis worldwide is posing a serious concern to tuberculosis management. The majority of Rif resistance in bacteria arises from mutations in the RpoB subunit of the RNA polymerase. We isolated M. smegmatis strains harbouring either an insertion (6 aa) or a deletion (10 aa) in their RpoB proteins. Although these strains showed a compromised fitness for growth in 7H9 Middlebrook medium, their resistance to Rif was remarkably high. The attenuated growth of the strains correlated with decreased specific activities of the RNA polymerases from the mutants. While the RNA polymerases from the parent or a mutant strain (harbouring a frequently occurring mutation, H442Y, in RpoB) were susceptible to Rif-mediated inhibition of transcription from calf thymus DNA, those from the insertion and deletion mutants were essentially refractory to such inhibition. Three-dimensional structure modelling revealed that the RpoB amino acids that interact with Rif are either deleted or unable to interact with Rif due to their unsuitable spatial positioning in these mutants. We discuss possible uses of the RpoB mutants in studying transcriptional regulation in mycobacteria and as potential targets for drug design.

A novel approach for large-scale polypeptide folding based on elastic networks using continuous optimization

We present a new computationally efficient method for large-scale polypeptide folding using coarse-grained elastic networks and gradient-based continuous optimization techniques. The folding is governed by minimization of energy based on Miyazawa–Jernigan contact potentials. Using this method we are able to substantially reduce the computation time on ordinary desktop computers for simulation of polypeptide folding starting from a fully unfolded state. We compare our results with available native state structures from Protein Data Bank (PDB) for a few de-novo proteins and two natural proteins, Ubiquitin and Lysozyme. Based on our simulations we are able to draw the energy landscape for a small de-novo protein, Chignolin. We also use two well known protein structure prediction software, MODELLER and GROMACS to compare our results. In the end, we show how a modification of normal elastic network model can lead to higher accuracy and lower time required for simulation.

Novel features of rapidly quenched melts of Bi2(Ca,Sr) 3Cu2O8+δ

By roller quenching and water quenching melts of Bi2(Ca, Sr)3Cu2O8+δ, glasses have been obtained. These glasses exhibit two glass transitions as well as two crystallization transitions. Microwave absorption studies show the glass to be weakly superconducting at 77 K, probably due to the presence of ultramicrocrystallites. The glass on crystallization at 870 K gives the crystalline n=1 member of the homologous series Bi2(Ca, Sr)n+1CunO 2n+4 and the n=2 member on annealing at 1100 K. The glass route provides a unique means of obtaining the n=2 member of the series. On prolonged annealing of the glass at 1120 K, the n=3 member seems to be formed.

Electroreduction of oxygen on some novel cobalt phthalocyanine complexes

The catalytic activity of cobalt phthalocyanine monomer and some of its polymeric derivatives towards the electroreduction of molecular oxygen in salt and alkaline solutions is examined. It is found that most of these complexes exhibit a higher catalytic activity than the cobalt phthalocyanine monomer.

Novel 1122 thallium cuprates showing high Tc superconductivity: TlCa1-xY,Ba2Cu2Oy,T,1-xPbxCaSr2Cu2Oy and TlCa0.5Ln0.5Sr2Cu2Oy

Substitution of Ca by Y in TlCaBa2Cu2Oy does not favour superconductivity, but substitution of Tl by Pb or of Ca by Ln (Ln = Y or rare earth) in TlCaSr2Cu2Oy results in high Tc superconductivity (Tc π 60-90 K). TlCa1-xLnxSr2Cu2Oy is a new series of high Tc superconductors, but the x = 0.0 composition does not exhibit bulk superconductivity.

Novel dielectric properties of glasses prepared by quenching melts of Bisingle bondCasingle bondSrsingle bondCusingle bondO cuprates

Glasses, prepared from the melts of Bi2(Ca, Sr)n+1 CunO2n+4 (n=1,2 and 3) have been characterized by various techniques. These glasses exhibit relatively high dielectric constants, high electrical conductivity, a ferroelectric-like dielectric hysteresis loop and pyroelectric effect at 300K. They also show weak microwave absorption at 77K.

Certain novel features of the R.F. response of the YBa2Cu3O7−x superconductors

The r.f. absorption experiment performed on YBa2Cu3O7-x ceramic pellets using a CW NMR spectrometer shows some novel observed in the microwave range.

From cages to wedges and clefts : Design of some novel hosts based on Image , Image , Image -triquinane framework

Annulation of aromatic rings on the folded Image ,Image ,Image -triquinane backbone has led to the design of potential host systems Image and Image whose crystal structures have been determined.

Novel composite coded pattern for small angle measurement using imaging method -art.no.62891D

A novel approach for measurement of small rotation angles using imaging method is proposed and demonstrated. A plane mirror placed on a precision rotating table is used for imaging the newly designed composite coded pattern. The imaged patterns are captured with the help of a CCD camera. The angular rotation of the plane mirror is determined from a pair of the images of the pattern, captured once before and once after affecting the tilt of the mirror. Both simulation and experimental results suggest that the proposed approach not only retains the advantages of the original imaging method but also contributes significantly to the enhancement of its measuring range (+/- 4.13 degrees with accuracy of the order of 1 arcsec).