Sudha Kartha,C(American Institute of Physics., January 13, 2007)
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Abstract:
Poly(methyl)methacrylate was made photoconducting by molecular doping and the
photoconductivity was investigated using modulated photocurrent technique . Low-temperature
current-voltage measurements showed that the transport mechanism was thermally activated
hopping. An experimental investigation of the photoconductivity action spectrum along with
theoretical calculation enabled an estimation of the diffusion coefficient of the material. The
presence of states with a distribution of lifetimes could be understood from the frequency response
of the photocurrent . The photocurrent was due to the field-assisted dissociation of these states.
Mohammed Yusuff, K K; Digna, Varghese; Arun, Vasudevan; Robinson, P P; Manju, Sebastian; Leeju, P; Varsha, Gopalakrishnan(International Union of Crystallography, Acta Crystallographica Section C ,Crystal Structure Communications, November 11, 2009)
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Abstract:
The Schiff base compounds N,N0-bis[(E)-quinoxalin-2-ylmethylidene]
propane-1,3-diamine, C21H18N6, (I), and N,N0-bis[(E)-
quinoxalin-2-ylmethylidene]butane-1,4-diamine, C22H20N6,
(II), crystallize in the monoclinic crystal system. These
molecules have crystallographically imposed symmetry.
Compound (I) is located on a crystallographic twofold axis
and (II) is located on an inversion centre. The molecular
conformations of these crystal structures are stabilized by
aromatic pye stacking interactions.
Mohammed Yusuff, K K; Manju, Sebastian; Arun, Vasudevan; Robinson, P P; Leeju, Pally; Digna, Varghese; Varsha, Gopalakrishnan(Taylor & Francis, Journal of Coordination Chemistry, October 15, 2009)
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Abstract:
The mononuclear cobalt(II) complex [CoL2] H2O (where HL is quinoxaline-2-carboxalidine-
2-amino-5-methylphenol) has been prepared and characterized by elemental analysis, conductivity
measurement, IR, UV-Vis spectroscopy, TG-DTA, and X-ray structure determination.
The crystallographic study shows that cobalt(II) is distorted octahedral with each tridentate
NNO Schiff base in a cis arrangement. The crystal exhibits a 2-D polymeric structure parallel to
[010] plane, formed by O-H...N and O-H... O intermolecular hydrogen bonds and pye
stacking interactions, as a racemic mixture of optical enantiomers. The ligand is a Schiff base
derived from quinoxaline-2-carboxaldehyde
Mohammed Yusuff, k K; Varsha, Gopalakrishnan; Arun, Vasudevan; Manju, Sebastian; Leeju, P; Digna, Varghese(Crystallography Journals,Acta Crystallographica Section E ,Structure Reports, March 24, 2009)
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Abstract:
The asymmetric unit of the title compound, C11H8N4, contains
two independent molecules. In the crystal structure, intermolecular
N—H.....N hydrogen bonds link molecules into
ribbons extended in the [100] direction
Girijavallabhan, C P; Radhakrishnan, P; V P N Nampoori; Geetha, K; Rajesh, M(Journal of Optics A: Pure and Applied Optics, Institute of Physics Publishing, January 13, 2006)
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Abstract:
We present a compact solid-state laser based on leaky mode propagation
from a dye-doped polymer free-standing film waveguide. The edge emitted
spectrum clearly indicated the existence of periodic resonant modes. The
reflections from the lateral faces of the free-standing film provided the
optical feedback thus giving rise to a Fabry–Perot like optical cavity. This
together with the guidance through the gain medium gave rise to intense
narrow emission lines. For a pump energy of 1.82 mJ/pulse, an intense line
with FWHM ∼0.4 nmwas observed at 576.5 nm.
Aparna,Lakshmanan S; Vijayakumar,Ambat(Department of Mathematics, 2000)
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Abstract:
In this paper, we study the domination number, the global dom
ination number, the cographic domination number, the global co
graphic domination number and the independent domination number
of all the graph products which are non-complete extended p-sums
(NEPS) of two graphs.
Indulal,G; Vijayakumar,A(Department of Mathematics, 2008)
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Abstract:
Eigenvalue of a graph is the eigenvalue of its adjacency matrix. The energy of a graph is the
sum of the absolute values of its eigenvalues. In this note we obtain analytic expressions for the
energy of two classes of regular graphs.
Renuka, T R; Ani Das, V; Paulose, C S(Department of Biotechnology, March 2, 2004)
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Abstract:
Muscarinic M1 and M3 receptor changes in the brain stem during pancreatic regeneration were investigated.
Brain stem acetylcholine esterase activity decreased at the time of regeneration . Sympathetic activity also
decreased as indicated by the norepinephrine (NE) and epinephrine (EPI) content of adrenals and also in the
plasma. Muscarinic Ml and M3 receptors showed reciprocal changes in the brain stem during regeneration.
Muscairnic M1 receptor number decreased at time of regeneration without any change in the affinity. High affinity
M3 receptors showed an increase in the number. The affinity did not show any change . The number of low affinity
receptors decreased with decreased Kd at 72 hours after partial pancreatectomy. The Kd reversed to control value
with a reversal of the number of receptors to near control value . Gene expression studies also showed a similar
change in the mRNA level of Ml and M3 receptors . These alterations in the muscarinic receptors regulate
sympathetic activity and maintain glucose level during pancreatic regeneration. Central muscarinic M1 and M3
receptor subtypes functional balance is suggested to regulate sympathetic and parasympathetic activity, which in
turn control the islet cell proliferation and glucose homeostasis.
Paulose,C S; Amee,Krishnakumar; Anu,Joseph(Department of Biotechnology, October 25, 2006)
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Abstract:
The recent developments in neurobiology have rendered new prominence
and potential to study about the structure and function of brain and related disorders.
Human behaviour is the net result of neural control of the communication between
brain cells. Neurotransmitters are chemicals that are used to relay, amplify and
modulate electrical signals between neurons and/or another cell. It mediates rapid
intercellular communication through the nervous system by interacting with cell
surface receptors. These receptors often trigger second messenger signaling pathways
that regulate the activity of ion channels. The functional balance of different
neurotransmitters such as Acetylcholine (Ach), Dopamine (DA), Serotonin (5-HT),
Norepinephrine (NE), Epinephrine (EPI), Glutamate and Gamma amino butyric acid
(GABA) regulates the growth, division and other vital functions of a normal cell /
organism (Sudha, 1998). Any change in neurotransmitters' functional balance will
result in the failure of cell function and may lead to the occurrence of diseases.
Abnormalities in the production or functioning of neurotransmitters have been
implicated in a number of neurological disorders like Schizophrenia, Alzheimer's,
Epilepsy, Depression and Parkinson's disease. Changes in central and peripheral
neuronal signaling system is also noted in diabetes, cancer, cell proliferation,
alcoholism and aging. Elucidation of neurotransmitters receptor interaction pathways
and gene expression regulation by second messengers and transcriptional factors
in health and disease conditions can lead to new small molecules for development
of therapeutic agents to improve neurological disease conditions. Increased
awareness of the global effects of neurological disorders should help health care
planners and the neurological community set appropriate priorities in research,
prevention, and management of these diseases.