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.
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.
Sulaiman,Pyroja; Binoy,Joseph; Paulose,C S(Department of Biotechnology, December 5, 2006)
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Abstract:
In the present study, serotonin 2C (5-HT2c) receptor binding parameters in the brainstem and cerebral cortex were investigated during
liver generation after partial hepatectomy (PH) and N-nitrosodiethylamine (NDEA) induced hepatic neoplasia in male Wistar rats. The
serotonin content increased significantly (p<0.01) in the cerebral cortex after PH and in NDEA induced hepatic neoplasia. Brain stem
serotonin content increased significantly (p<0.05) after PH and (p<0.001) in NDEA induced hepatic neoplasia. The number and affinity of
the 5-HT2c receptors in the crude synaptic membrane preparations of the brain stem showed a significant (p<0.001) increase after PH and in
NDEA induced hepatic neoplasia. The number and affinity of 5-HT2c receptors increased significantly (p<0.001) in NDEA induced hepatic
neoplasia in the crude synaptic membrane preparations of the cerebral cortex. There was a significant (p<0.01) increase in plasma
norepinephrine in PH and (p<0.001) in NDEA induced hepatic neoplasia, indicating sympathetic stimulation. Thus, our results suggest that
during active hepatocyte proliferation 5-HT2c receptor in the brain stem and cerebral cortex are up-regulated which in turn induce hepatocyte
proliferation mediated through sympathetic stimulation.
This paper presents gamma stochastic volatility models and investigates its distributional
and time series properties. The parameter estimators obtained by the
method of moments are shown analytically to be consistent and asymptotically
normal. The simulation results indicate that the estimators behave well. The insample
analysis shows that return models with gamma autoregressive stochastic
volatility processes capture the leptokurtic nature of return distributions and
the slowly decaying autocorrelation functions of squared stock index returns
for the USA and UK. In comparison with GARCH and EGARCH models, the
gamma autoregressive model picks up the persistence in volatility for the US
and UK index returns but not the volatility persistence for the Canadian and
Japanese index returns. The out-of-sample analysis indicates that the gamma
autoregressive model has a superior volatility forecasting performance compared
to GARCH and EGARCH models.
Radhakrishnan, P; V P N Nampoori; Girijavallabhan, C P; Geetha, K; Rajesh, M(Journal of Optics A: Pure and Applied Optics, Institute of Physics Publishing, January 13, 2006)
[+]
[-]
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.
V P N Nampoori; Radhakrishnan, P; Girijavallabhan, C P; Geetha, K; Rajesh, M(Journal of Optics A: Pure and Applied Optics, Institute of Physics Publishing, January 13, 2006)
[+]
[-]
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.
Optical emission spectroscopic studies were carried out on the plasma produced by ablation of zinc
oxide target using the third harmonic 355 nm of Q-switched Nd:YAG laser, in vacuum and at three
different ambient gas oxygen pressures. The spatial variations of electron density Ne and electron
temperature Te were studied up to a distance of 20 mm from the target surface. The kinematics of
the emitted particles and the expansion of the plume edge are discussed. The optimum conditions
favorable for the formation of high quality zinc oxide thin films are thereby suggested.
Zinc oxide (ZnO) thin films were deposited on quartz, silicon, and polymer substrates by pulsed laser deposition (PLD)
technique at different oxygen partial pressures (0.007 mbar to 0.003 mbar). Polycrystalline ZnO films were obtained at
room temperature when the oxygen pressure was between 0.003 mbar and .007 mbar, above and below this pressure the
films were amorphous as indicated by the X-ray diffraction (XRD). ZnO films were deposited on Al2O3 (0001) at
different substrate temperatures varying from 400oC to 600oC and full width half maximum (FWHM) of XRD peak is
observed to decrease as substrate temperature increases. The optical band gaps of these films were nearly 3.3 eV. A
cylindrical Langmuir probe is used for the investigation of plasma plume arising from the ZnO target. The spatial and
temporal variations in electron density and electron temperature are studied. Optical emission spectroscopy is used to
identify the different ionic species in the plume. Strong emission lines of neutral Zn, Zn+ and neutral oxygen are
observed. No electronically excited O+ cations are identified, which is in agreement with previous studies of ZnO plasma
plume.
Jayaraj, M K(American Institute of Physics, January 4, 2006)
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Abstract:
The radio frequency plasma generated during the sputtering of Indium Tin Oxide target using Argon
was analyzed by Langmuir probe and optical-emission spectroscopy. The basic plasma parameters
such as electron temperature and ion density were evaluated. These studies were carried out by
varying the RF power from 20 to 50 W. A linear increase in ion density and an exponential decrease
in electron temperature with rf power were observed. The measured plasma parameters were then
correlated with the properties of ITO thin films deposited under similar plasma conditions.