Joshy Joseph

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All organisms store the information necessary to maintain life in their DNA. Any process that damages DNA, causing a loss or corruption of that information, jeopardizes the viability of the organism. One-electron oxidation is such a process. In this Account, we address three of the central features of one-electron oxidation of DNA: (i) the migration of the(More)
During recent years, we have witnessed a major paradigm shift in distributed computing principles, with a focus towards service orientation, open standards integration, collaboration, and virtualization. One particular area of interest centers on the evolution of grid computing principles into the mainstream of distributed computing and Web services. In(More)
A series of acridinium derivatives 1-6, wherein steric factors have been varied systematically through substitution at the 9 position of the acridine ring, have been synthesized and their DNA interactions have been investigated by various biophysical techniques. The unsubstituted and methylacridinium derivatives 1 and 2 and the o-tolylacridinium derivative(More)
Novel bifunctional conjugates 1-3, with varying polymethylene spacer groups, were synthesized, and their DNA interactions have been investigated by various biophysical techniques. The absorption spectra of these systems showed bands in the regions of 300-375 and 375-475 nm, corresponding to acridine and acridinium chromophores, respectively. When compared(More)
A new series of photoactivated DNA oxidizing agents in which an acridine moiety is covalently linked to viologen by an alkylidene spacer was synthesized, and their photophysical properties and interactions with DNA, including DNA cleaving properties, were investigated. The fluorescence quantum yields of the viologen-linked acridines were found to be lower(More)
Thymine-Hg(II)-thymine base pairs have been incorporated in an oligonucleotide duplex to study their effect on DNA-mediated charge transport. The introduction of a formally charged Hg atom inside the DNA base core does not significantly alter the charge hopping and trapping properties, as discussed in this paper. Hg(II) replaces the protons normally found(More)
The feature article is a review of the reaction of thymine in the one-electron oxidation of duplex DNA. Oxidation of DNA causes chemical reactions that result in remote damage (mutation) to a nucleobase. Normally this reaction occurs at guanine, but in oligonucleotides that lack guanines, or when the DNA contains a thymine-thymine mispair, reaction occurs(More)
The discovery that electron holes (radical cations) migrate long distances in DNA has fostered enormous interest in the mechanism of this processes, due in large part to its apparent similarity with oxidative damage in cells.1,2 Several models have been proposed to account for the extensive experimental observations in this area. Currently, it is generally(More)
Port causes environmental and health concerns in coastal cities if its operation and development are not made environmentally compatible and sustainable. An emission inventory is necessary to assess the impact of port projects or growth in marine activity as well as to plan mitigation strategies. In this study, a detailed emission inventory of total(More)
The one-electron oxidation of a series of DNA oligonucleotides was examined. Each oligomer contains a covalently linked anthraquinone (AQ) group. Irradiation of the AQ group with near-UV light results in a one-electron oxidation of the DNA that generates a radical cation (electron "hole"). The radical cation migrates through the DNA by a hopping mechanism(More)