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.
Jackson,James; Paulose,C S(Department of Biotechnology, May 1, 2000)
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Abstract:
5-HT2A receptor binding parameters were studied in the cerebral cortex and brain stem of
control, diabetic, insulin, insulin + tryptophan and tr3yptophan treated streptozotocin diabetic
rats. Scatchard analysis using selective antagonist, [-H](±)2,3-dimethoxyphenyl-l-[2-(4-piperidine)-
methanol] ([3H]MDL100907) in cerebral cortex of diabetic rats showed a significant
decrease in dissociation constant (Kd) without any change in maximal binding (Bm). Competition
binding studies in cerebral cortex using ketanserin against [3H]MDL100907 showed
the appearance of an additional site in the low affinity region during diabetes. In the brain
stem, Scatchard analysis showed a significant increase in Bmax and Kd. Displacement studies
showed a shift in the receptor affinity towards a low affinity state. All these altered parameters
in diabetes were reversed to control level by insulin, insulin + tryptophan and tryptophan
treatments. Tryptophan treatment is suggested to reverse the altered 5-HT2Abinding and
blood glucose level to control status by increasing the brain 5-HT content.
Radhakrishnan, P; V P N Nampoori; Girijavallabhan, C P; Nibu, A George; George, A K(Journal of Physics D : Applied Physics, October 13, 2000)
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Abstract:
We report on a laser induced photoacoustic study of the nematic-to-isotropic
transition in certain commercial nematic liquid crystal mixtures, namely BL001, BL002,
BL032 and BL035. A simple analysis of the experimental data using the
Rosencwaig–Gersho theory shows that the heat capacities of all these compounds exhibit a
sharp peak as the temperature of the sample is varied across the transition region. Also,
substantial differences in the photoacoustic signal amplitudes in nematic and isotropic phases
have been noticed for all the mixtures. The increased light scattering property of the nematic
phase may be the reason for the enhanced photoacoustic signal amplitude in this phase
V P N Nampoori; Radhakrishnan, P; Girijavallabhan, C P; Nibu, A George; George, A K(Journal of Physics D : Applied Physics, October 13, 2000)
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Abstract:
We report on a laser induced photoacoustic study of the nematic-to-isotropic
transition in certain commercial nematic liquid crystal mixtures, namely BL001, BL002,
BL032 and BL035. A simple analysis of the experimental data using the
Rosencwaig–Gersho theory shows that the heat capacities of all these compounds exhibit a
sharp peak as the temperature of the sample is varied across the transition region. Also,
substantial differences in the photoacoustic signal amplitudes in nematic and isotropic phases
have been noticed for all the mixtures. The increased light scattering property of the nematic
phase may be the reason for the enhanced photoacoustic signal amplitude in this phase.
Ceramic dielectric resonators in the BaO-RE2O3-TiO2 (RE = rare earth) system have been
prepared by the conventional solid state ceramic route. The dielectric properties have been
tailored by substitution of different rare earth oxides and by bismuth oxide addition. The
dielectric constants increased with Bi addition whereas the 0 decreased. The temperature
coefficient of the resonant frequency improved with bismuth addition
A microwave dielectric ceramic resonator based on BaCe2Ti5O15 and Ba5Nb4O15 have been prepared by conventional solid state ceramic route. The dielectric resonators (DRs) have high dielectric constant 32 and 40 for BaCe2Ti5O15 and Ba5Nb4O15, respectively. The whispering gallery mode (WGM) technique was employed for the accurate determination of the dielectric properties in the microwave frequency range. The BaCe2Ti5O15 and Ba5Nb4O15 have quality factors (Q X F) of 30,600 and 53,000 respectively. The quality factor is found to depend on the azimuthal mode numbers. The temperature coefficient of resonant frequency (Tr) of BaCe2Ti5O15 and Ba5Nb4O15 have been measured accurately using different
resonant modes and are + 41 and + 78 ppm/K, respectively
Biju,M P; Pyroja,Sulaiman; Rajeshkumar,Neelimmathara V; Paulose,C S(Department of Biotechnology, September 20, 2000)
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Abstract:
GABAergic alterations in hypothalamus during compensatory hyperplasia after partial hepatectomy (PH), lead nitrate (LN)
induced direct hyperplasia and N-nitrosodiethylamine (NDEA) induced neoplasia in liver were investigated. Serum GABA
levels were increased in all 3 experimental groups compared with the control. GABA content decreased in hypothalamus of
PH and NDEA treated rats, while it increased in LN treated rats. GABAA receptor number and affinity in hypothalamic membrane
preparations of rats showed a significant decrease in PH and NDEA treated rats, while in LN treated rats the affinity
increased without any change in the receptor number. The GABAB receptor number increased in PH and NDEA treated rats,
while it decreased in LN treated rats. The affinity of the receptor also increased in NDEA treated rats. Plasma NE levels
showed significant increase in PH and NDEA rats compared with the control while it decreased in LN treated rats. The results
of the present study suggests that liver cell proliferation is influencing the hypothalamic GABAergic neurotransmission
and these changes regulate the hepatic proliferation through the sympathetic stimulation.
Rani, Joseph(John Wiley & Sons, Inc., March 20, 2000)
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Abstract:
ABSTRACT: Zinc salts of ethyl, isopropyl, and butyl xanthates were prepared in the
laboratory. They were purified by reprecipitation and were characterized by IR, NMR,
and thermogravimetric analysis techniques. The melting points were also determined.
The rubber compounds with different xanthate accelerators were cured at temperatures
from 30 to 150°C. The sheets were molded and properties such as tensile strength,
tear strength, crosslink density, elongation at break, and modulus at 300% elongation
were evaluated. The properties showed that all three xanthate accelerators are effective
for room temperature curing.
Sreekumar, K; Thomas, Mathew; Mirajkar, S P; Sugunan, S; Rao, B S(Elsevier, 2000)
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Abstract:
The catalyst compositions of the Zn1−xCOxFe2O4 (x= 0, 0.2, 0.5, 0.8 and 1.0) spiel series possessing ‘x’ values, x less than or equal to 0.5, are
unique for selective N-monomethylation of aniline using methanol as the alkylating agent. Since dimethyl carbonate (DMC)
is another potential non-toxic alkylating agent, alkylation of aniline was investigated over various Zn–Co ferrites using DMC
as the alkylating agent. The merits and demerits of the two alkylating agents are compared. Catalytic activity followed a
similar trend with respect to the composition of the ferrospinel systems. DMC is active at comparatively low temperature,
where methanol shows only mild activity. However, on the selectivity basis, DMC as an alkylating agent could not compete
with methanol, since the former gave appreciable amounts of N,N-dimethylaniline (NNDMA) even at low temperature where
methanol gave nearly 99% N-methylaniline (NMA) selectivity. As in the case of methanol, DMC also did not give any
C-alkylated products.