Arun Nm - Academia.edu (original) (raw)
Papers by Arun Nm
Compressibility of the gamma phase of Fe2O3 (Maghemite) nano-particles was studied using angle di... more Compressibility of the gamma phase of Fe2O3 (Maghemite) nano-particles was studied using angle dispersive x-ray diffraction on the micro-diffraction beamline at HPCAT of the Advanced Photon Source. Nano-particles of three different sizes (3 and10 and 20 nm) were studied up to 31 GPa using a diamond anvil cell equipped with c-BN seats. Two samples were synthesized by treating sulfonated divinyl benzene polystyrene resin matrix with aqueous solutions of (1) FeCl2,(2) FeCl3. The particle size of γ-Fe2O3 prepared using FeCl3 was ˜ 3 nm and with FeCl2 was ˜ 10 nm. The 20 nm particle size sample was bought commercially. The bulk modulii for 10 nm and 20 nm samples were 212 (5) and 207 (5) GPa which are close to the bulk value of 203 (10) GPa, whereas 3.4 nm sample shows a higher value of 240 (5) GPa. Transition pressure (Ptr) at which maghemite transforms to hematite varies with particle size and was estimated to be 10 (2) GPa, 17 (2) GPa and 27 (2) GPa for 3 nm, 10 nm and 20 nm particle size samples, respectively.
Electronics Letters, 1997
... AK Srivastava, SL Zyskind, TA Strasser, JR Pedrazzani, C. Wolf, J. Zhou, SB Judkins, RP Espin... more ... AK Srivastava, SL Zyskind, TA Strasser, JR Pedrazzani, C. Wolf, J. Zhou, SB Judkins, RP Espindola and AM Vengsarkar Indexing terms: Erbium-doped fibre amplifiers, Wavelength division multiplexing, Opticmil communication The authors demonstrate a two band architecture ...
International Journal of Modern Physics B, 2007
The photoexcited carrier lifetime in ZnSe and CdSe (direct band gap crystals) and CdI2 and PbI2 (... more The photoexcited carrier lifetime in ZnSe and CdSe (direct band gap crystals) and CdI2 and PbI2 (indirect band gap crystals) has been investigated by the use of a single beam Z-scan technique at 532 nm. The carrier lifetime (tau) is determined to be (1.7 ± 0.5) ns in the case of direct band gap and (1.2 ± 0.03) ps in
Photochemistry and Photobiology, 2004
Halogenated squaraine dyes 1 and 2 possess favorable photophysical and in vifro photobiological p... more Halogenated squaraine dyes 1 and 2 possess favorable photophysical and in vifro photobiological properties that make these new class of molecules interesting for photodynamic therapeutic applications. For a better understanding of the mechanism of their photobiological activity, we have analyzed the DNA damage and the cytotoxicity induced by these photosensitizers in mammalian cells and cell-free systems in the presence and absence of various additives and scavengers. Both photoactivated squaraines were found to be similar efficient in inducing single-strand breaks (SSB) in cellfree DNA when compared with the cellular DNA. Superoxide dismutase and catalase did not show any influence. However, the presence of tert-butanol and glutathione inhibited the formation of the DNA SSB, indicating an indirect (possibly squaraine radical mediated) mechanism under cell-free conditions. Replacing H 2 0 in the buffer by D20 resulted in a five-to six-fold increase in the number of the SSB in cell-free DNA and a significant enhancement of the photocytotoxicity in mouse lymphoma cells. The results demonstrate that singlet oxygen is the major reactive species under cell-free and cellular conditions and confirm that squaraine-based sensitizers 1 and 2 can have potential applications in photodynamic therapy.
Biological Psychiatry, 1999
Background: Efforts to model putative serotonergic deficits associated with affective disorders h... more Background: Efforts to model putative serotonergic deficits associated with affective disorders have frequently involved acute tryptophan depletion (ATD) as a manipulation strategy aimed at lowering brain serotonin synthesis. In an attempt to widen the scope of the measurement probes used in these investigations, the central actions of ATD and a subsequent dose of fenfluramine were examined via utilization of quantitative electroencephalography (EEG) and mood ratings.
Compressibility of the gamma phase of Fe2O3 (Maghemite) nano-particles was studied using angle di... more Compressibility of the gamma phase of Fe2O3 (Maghemite) nano-particles was studied using angle dispersive x-ray diffraction on the micro-diffraction beamline at HPCAT of the Advanced Photon Source. Nano-particles of three different sizes (3 and10 and 20 nm) were studied up to 31 GPa using a diamond anvil cell equipped with c-BN seats. Two samples were synthesized by treating sulfonated divinyl benzene polystyrene resin matrix with aqueous solutions of (1) FeCl2,(2) FeCl3. The particle size of γ-Fe2O3 prepared using FeCl3 was ˜ 3 nm and with FeCl2 was ˜ 10 nm. The 20 nm particle size sample was bought commercially. The bulk modulii for 10 nm and 20 nm samples were 212 (5) and 207 (5) GPa which are close to the bulk value of 203 (10) GPa, whereas 3.4 nm sample shows a higher value of 240 (5) GPa. Transition pressure (Ptr) at which maghemite transforms to hematite varies with particle size and was estimated to be 10 (2) GPa, 17 (2) GPa and 27 (2) GPa for 3 nm, 10 nm and 20 nm particle size samples, respectively.
Electronics Letters, 1997
... AK Srivastava, SL Zyskind, TA Strasser, JR Pedrazzani, C. Wolf, J. Zhou, SB Judkins, RP Espin... more ... AK Srivastava, SL Zyskind, TA Strasser, JR Pedrazzani, C. Wolf, J. Zhou, SB Judkins, RP Espindola and AM Vengsarkar Indexing terms: Erbium-doped fibre amplifiers, Wavelength division multiplexing, Opticmil communication The authors demonstrate a two band architecture ...
International Journal of Modern Physics B, 2007
The photoexcited carrier lifetime in ZnSe and CdSe (direct band gap crystals) and CdI2 and PbI2 (... more The photoexcited carrier lifetime in ZnSe and CdSe (direct band gap crystals) and CdI2 and PbI2 (indirect band gap crystals) has been investigated by the use of a single beam Z-scan technique at 532 nm. The carrier lifetime (tau) is determined to be (1.7 ± 0.5) ns in the case of direct band gap and (1.2 ± 0.03) ps in
Photochemistry and Photobiology, 2004
Halogenated squaraine dyes 1 and 2 possess favorable photophysical and in vifro photobiological p... more Halogenated squaraine dyes 1 and 2 possess favorable photophysical and in vifro photobiological properties that make these new class of molecules interesting for photodynamic therapeutic applications. For a better understanding of the mechanism of their photobiological activity, we have analyzed the DNA damage and the cytotoxicity induced by these photosensitizers in mammalian cells and cell-free systems in the presence and absence of various additives and scavengers. Both photoactivated squaraines were found to be similar efficient in inducing single-strand breaks (SSB) in cellfree DNA when compared with the cellular DNA. Superoxide dismutase and catalase did not show any influence. However, the presence of tert-butanol and glutathione inhibited the formation of the DNA SSB, indicating an indirect (possibly squaraine radical mediated) mechanism under cell-free conditions. Replacing H 2 0 in the buffer by D20 resulted in a five-to six-fold increase in the number of the SSB in cell-free DNA and a significant enhancement of the photocytotoxicity in mouse lymphoma cells. The results demonstrate that singlet oxygen is the major reactive species under cell-free and cellular conditions and confirm that squaraine-based sensitizers 1 and 2 can have potential applications in photodynamic therapy.
Biological Psychiatry, 1999
Background: Efforts to model putative serotonergic deficits associated with affective disorders h... more Background: Efforts to model putative serotonergic deficits associated with affective disorders have frequently involved acute tryptophan depletion (ATD) as a manipulation strategy aimed at lowering brain serotonin synthesis. In an attempt to widen the scope of the measurement probes used in these investigations, the central actions of ATD and a subsequent dose of fenfluramine were examined via utilization of quantitative electroencephalography (EEG) and mood ratings.