Indian Association for the Cultivation of Science

About: Indian Association for the Cultivation of Science is a education organization based out in Kolkata, India. It is known for research contribution in the topics: Catalysis & Excited state. The organization has 3867 authors who have published 10457 publications receiving 220098 citations.

Electrical transport and dielectric relaxation in Fe3O4-polypyrrole hybrid nanocomposites.

Abstract: The polymerization of pyrrole in an aqueous medium in the presence of nanodimensional Fe3O4 using ammonium peroxodisulphate (APS) as oxidant results in the formation of polypyrrole?Fe3O4 nanocomposites. Characterization of the composites was carried out by Fourier transform infrared spectroscopy, x-ray diffraction, scanning and transmission electron microscopy. The magnetization data exhibit a small hysteresis loop at room temperature. The M?ssbauer spectra at room temperature reveal the doublet structure, characteristic of the superparamagnetic phase in magnetite (Fe3O4). The composite samples reveal ordered semiconducting behaviour. Polypyrrole is the dominating component in the transport process of the nanocomposites. A very large dielectric constant of about 11?000 at room temperature has been observed. The interface between polypyrrole and Fe3O4 plays an important role in producing a large dielectric constant in the composite.

Characterization and identification of dityrosine cross-linked peptides using tandem mass spectrometry

Abstract: The use of mass spectrometry coupled with chemical cross-linking of proteins has become a powerful tool for proteins structure and interactions studies. Unlike structural analysis of proteins using chemical reagents specific for lysine or cysteine residues, identification of gas-phase fragmentation patterns of endogenous dityrosine cross-linked peptides have not been investigated. Dityrosine cross-linking in proteins and peptides are clinical markers of oxidative stress, aging, and neurodegenerative diseases including Alzheimer’s disease and Parkinson’s disease. In this study, we investigated and characterized the fragmentation pattern of a synthetically prepared dityrosine cross-linked dimer of Aβ(1–16) using ESI tandem mass spectrometry. We then detailed the fragmentation pattern of dityrosine cross-linked Aβ(1–16), using collision induced dissociation (CID), higher-energy collision induced dissociation (HCD), electron transfer dissociation (ETD), and electron capture dissociation (ECD). Application of ...