Joshy Joseph

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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)
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)
One-electron oxidation of A/T-rich DNA leads to mutations at thymine. Experimental investigation of DNA containing methyl-deuterated thymine reveals a large isotope effect establishing that cleavage of this carbon-hydrogen bond is involved in the rate-determining step of the reaction. First-principles quantum calculations reveal that the radical cation(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)
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)
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)
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)
Charged-particle spectra associated with direct photon (γ dir) and π 0 are measured in p+p and Au+Au collisions at center-of-mass energy √ s N N = 200 GeV with the STAR detector at RHIC. A shower-shape analysis is used to partially discriminate between γ dir and π 0. Assuming no associated charged particles in the γ dir direction (near side) and small(More)
Grid computing enables resource sharing and dynamic allocation of distributed heterogeneous computational resources while minimizing the associated ownership and operating cost. In grid computing there is no matter where data located is or which computer processes a task. Quality of Service parameters plays a key role in selecting Grid resources and(More)