Paulose,C S; Dakshinamurti,K(Department of Biotechnology, June 12, 1987)
[+]
[-]
Abstract:
Chronic catheterization is illustrated using vascular-access-port model SLA where the port is surgically placed subcutaneously on
the back of the rat. The catheter is tunnelled to the neck and inserted into the jugular vein . Within 24 h rats showed normal blood
pressure and blood samples were collected at intervals with minimal stress to the animals . A comparison of the plasma catecholamine
of blood collected from vascular-access-ports with that obtained from decapitation indicates that there was minimal stress to the rats
when blood was drawn through the vascular-access-port.
Rani, Joseph(Hutig & Wepf Verlag,Basel, October 5, 1987)
[+]
[-]
Abstract:
Compounding of styrene-butadiene copolymer/polybutadiene , natural rubber/
ethylene-propylene-diene terpolymer and natural rubber/butadiene-acrylonitrile copolymer
blends was done in three different ways and their curing behaviour and the
tensile properties of the es are compared.
Paulose,C S; Dakshinamurti,K; Subah,Packer; Newman,L Stephens(Department of Biotechnology, December 8, 1987)
[+]
[-]
Abstract:
Pyridoxal phosphate is the coenzyme of various decarboxylases involved in the formation
of monoamine neurotransmitters such as y-aminobutyric acid , serotonin , dopamine, and norepinephrine
. Adult male Sprague-Dawley rats placed on a pyridoxine -deficient diet for 8 weeks showed
significant hypertension compared with pyridoxine -supplemented controls . Hypothalamic contents of
pyridoxal phosphate , y-aminobutyric acid, and serotonin in the pyridoxine - deficient rats were significantly
lower than those in pyridoxine -supplemented controls . Hypertension was associated with
sympathetic stimulation . Treatment of pyridoxine-deficient rats with a single dose of pyridoxine (10
mg/kg body weight) reversed the blood pressure to normal levels within 24 hours, with concomitant
restorations of hypothalamic serotonin and y-aminobutyric acid as well as the return of plasma
norepinephrine and epinephrine to normal levels . Also, pyridoxine treatment reversed the hypothalamic
hypothyroidism observed in pyridoxine -deficient rats . These results indicate an association
between pyridoxine deficiency and sympathetic stimulation leading to hypertension.
Abdul Rasheed, T M; Moosad, K P B; Nampoori, V P N; Sathianandan, K(American Chemical Society, 1987)
[+]
[-]
Abstract:
Vibrational overtone spectra of acetophenone and benzaldehyde in the visible and near-infrared regions are studied by the
dual beam thermal lens and the conventional near-infrared absorption techniques. The observed increase in the mechanical
frequency of the aryl CH bond from that of benzene is attributed to the decrease in the aryl CH bond length caused by
the electron-withdrawing property of the substituents. Overtone spectra also demonstrate that acetophenone contains two
types of methyl CH bonds arising from the anisotropic environments created by oxygen lone pair and carbonyl P electrons.
The local-mode parameters of the two types of CH bonds are compared with those of acetone and acetaldehyde. The possible
factors influencing the methyl CH bonds in acetophenone are discussed.
Natural rubber, styrene-butadiene rubber, and polybutadiene
rubber were used to replace part of the butadieneacrylonitrile
rubber in a 70/30 butadiene-acrylonitrile rubber/
poly(vinyl chloride) blend. Such replacement up to 15%
of the total weight of the blend improved the mechanical
properties, while decreasing the cost of the blend. Styrenebutadiene
rubber could replace butadiene-acrylonitrile
rubber up to 30% of the total weight of the blend without
deterioration in the mechanical properties.
Reghunath, A T; Nampoori, V P N(Springer, November , 1987)
[+]
[-]
Abstract:
Using laser transmission, the characteristics of hydrodynamic turbulence is studied following one of the recently developed technique in nonlinear dynamics. The existence of deterministic chaos in turbulence is proved by evaluating two invariants viz. dimension of attractor and Kolmogorov entropy. The behaviour of these invariants indicates that above a certain strength of turbulence the system tends to more ordered states.
Harikrishnan, K P; Nandakumaran, V M(Pramana, December , 1987)
[+]
[-]
Abstract:
We have studied the bifurcation structure of the logistic map with a time dependant control parameter. By introducing a specific nonlinear variation for the parameter, we show that the bifurcation structure is modified qualitatively as well as quantitatively from the first bifurcation onwards. We have also computed the two Lyapunov exponents of the system and find that the modulated logistic map is less chaotic compared to the logistic map.
The role of acoustic plasmons in the recently discovered high Tc superconductors
is discussed. It is shown that the exchange of acoustic plasmons together with the
usual phonon exchange between electrons can give rise to a Tc - 100 K.
Harikrishnan, K P; Nandakumaran, V M(Elsevier, December 7, 1987)
[+]
[-]
Abstract:
We study the period-doubling bifurcations to chaos in a logistic map with a nonlinearly modulated parameter and show that the bifurcation structure is modified significantly. Using the renormalisation method due to Derrida et al. we establish the universal behaviour of the system at the onset of chaos.