Parvathi, M R; Dr. Nandakumaran, V M(Cochin University of Science & Technology, May , 2009)
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Abstract:
In this thesis we have presented some aspects of the nonlinear dynamics of
Nd:YAG lasers including synchronization, Hopf bifurcation, chaos control
and delay induced multistability.We have chosen diode pumped Nd:YAG
laser with intracavity KTP crystal operating with two mode and three mode
output as our model system.Different types of orientation for the laser cavity
modes were considered to carry out the studies. For laser operating with two
mode output we have chosen the modes as having parallel polarization and
perpendicular polarization. For laser having three mode output, we have
chosen them as two modes polarized parallel to each other while the third
mode polarized orthogonal to them.
Description:
International School of Photonics,
Cochin University of Science and Technology
Mathew, K T; Anil, Lonappan; Paul, Benzy; Thimothy, V O; Rajasekaran, C; Vinu, Thomas; Joe, Jacob(Wiley InterScience, January , 2009)
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Abstract:
This article reports a new method of analyzing pericardial
fluid based on the measurement of the dielectric properties at microwave
frequencies. The microwave measurements were performed by
rectangular cavity perturbation method in the S-band of microwave frequency
with the pericardial fluid from healthy persons as well as from
patients suffering from pericardial effusion. It is observed that a remarkable
change in the dielectric properties of patient samples with the
normal healthy samples and these measurements were in good agreement
with clinical analysis. This measurement technique and the method
of extraction of pericardial fluid are simple. These results give light to
an alternative in-vitro method of diagnosing onset pericardial effusion
abnormalities using microwaves without surgical procedure.
Sreedevi N, kutty; Dr. Damodaran, R; Dr. Rosamma, Philip(Cochin University of Science & Technology, November , 2009)
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Abstract:
The present study provides an account of the occurrence and diversity of
marine yeasts in the slope sediments of Arabian Sea and Bay of Bengal. It also
gives a clear idea about the role of yeasts in the benthic realm of marine
ecosystem. The lipolytic potential of the organisms indicate the presence of rich
lipid moieties in the study area. The isolates, Candida sp. SD 302 and Pichia
guilliermondii SD 337 were proved to have potential oil degrading property and
can be employed as bioremediators of oil spill after further characterization. The
black yeasts isolated during the study area were found to have high commercial
value by virtue of the by-products obtained from them. The melanin and the
melanin degrading enzyme extracted from these organisms are potential
bioactive materials for application in cosmetology.
Description:
Department of Marine Biology, Microbiology and Biochemistry, Cochin University of Science and Technology
Digital library Initiatives in India, models of electronic and print publishing, digitallibrary and funding, chaalenges and oppertunities,digital ibrary initiatives in India, current digital library moedels etc
Epilepsy is a syndrome of episodic brain dysfunction characterized by recurrent unpredictable, spontaneous
seizures. Cerebellar dysfunction is a recognized complication of temporal lobe epilepsy and it is associated
with seizure generation, motor deficits and memory impairment. Serotonin is known to exert a modulatory
action on cerebellar function through 5HT2C receptors. 5-HT2C receptors are novel targets for developing anticonvulsant
drugs. In the present study, we investigated the changes in the 5-HT2C receptors binding and gene
expression in the cerebellum of control, epileptic and Bacopa monnieri treated epileptic rats. There was a
significant down regulation of the 5-HT content (pb0.001), 5-HT2C gene expression (pb0.001) and 5-HT2C
receptor binding (pb0.001) with an increased affinity (pb0.001). Carbamazepine and B. monnieri treatments
to epileptic rats reversed the down regulated 5-HT content (pb0.01), 5-HT2C receptor binding (pb0.001) and
gene expression (pb0.01) to near control level. Also, the Rotarod test confirms the motor dysfunction and
recovery by B. monnieri treatment. These data suggest the neuroprotective role of B. monnieri through the
upregulation of 5-HT2C receptor in epileptic rats. This has clinical significance in the management of epilepsy
Paulose, C S; Athira, Babu; Anju, T R(Indian Journal of Biochemistry and Biophysics, April , 2009)
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Abstract:
Hypoxia is one of the major causes of damage to the fetal and neonatal brain and cardiac functions. in earlier studies we have reported the brain damage caused by hypoxia and resusciation with oxygen and epinephrine and have found that glucose treatment to hypoxic rats and hypoxic rats treated with oxygen shows a reversal of brain damage. during this study the findings may have clinical significance in the proper management of heart and brain functions.
Ajithkumar, G; Dr. Bhasi, M(Cochin University of Science & Technology, July , 2009)
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Abstract:
Poor cold flow properties of vegetable oils are a major problem preventing the
usage of many abundantly available vegetable oils as base stocks for industrial lubricants.
The major objective of this research is to improve the cold flow properties of vegetable
oils by various techniques like additive addition and different chemical modification
processes. Conventional procedure for determining pour point is ASTM D97 method. ASTM
D97 method is time consuming and reproducibility of pour point temperatures is poor
between laboratories. Differential Scanning Calorimetry (DSC) is a fast, accurate and
reproducible method to analyze the thermal activities during cooling/heating of oil. In
this work coconut oil has been chosen as representative vegetable oil for the analysis and
improvement cold flow properties since it is abundantly available in the tropics and has a
very high pour point of 24 °C. DSC is used for the analysis of unmodified and modified
vegetable oil. The modified oils (with acceptable pour points) were then
subjected to different tests for the valuation of important lubricant properties such as
viscometric, tribological (friction and wear properties), oxidative and corrosion
properties.A commercial polymethacrylate based PPD was added in different percentages and the pour points
were determined in each case. Styrenated phenol(SP) was added in different
concentration to coconut oil and each solution was subjected to ASTM D97 test and
analysis by DSC. Refined
coconut oil and other oils like castor oil, sunflower oil and keranja oil were mixed in
different proportions and interesterification procedure was carried out. Interesterification
of coconut oil with other vegetable oils was not found to be effective in lowering the pour
point of coconut oil as the reduction attained was only to the extent of 2 to 3 °C.Chemical modification by acid catalysed condensation reaction with coconut oil
castor oil mixture resulted in significant reduction of pour point (from 24 ºC to -3 ºC).
Instead of using triacylglycerols, when their fatty acid derivatives (lauric acid- the major
fatty acid content of coconut oil and oleic acid- the major fatty acid constituents of monoand
poly- unsaturated vegetable oils like olive oil, sunflower oil etc.) were used for the
synthesis , the pour point could be brought down to -42 ºC. FTIR and NMR spectroscopy
confirmed the ester structure of the product which is fundamental to the biodegradability
of vegetable oils. The tribological performance of the synthesised product with a suitable AW/EP
additive was comparable to the commercial SAE20W30 oil. The viscometric properties
(viscosity and viscosity index) were also (with out additives) comparable to commercial
lubricants. The TGA experiment confirmed the better oxidative performance of the
product compared to vegetable oils. The sample passed corrosion test as per ASTM D130
method.
Description:
School of Engineering, Cochin University of Science and Technology
Paulose, C S; Peeyush, K T; Anju, T R(Springer Science+Business Media, LLC 2009, 2009)
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Abstract:
Hypoxia in neonates can lead to biochemical
and molecular alterations mediated through changes in
neurotransmitters resulting in permanent damage to brain.
In this study, we evaluated the changes in the receptor
status of GABAA in the cerebral cortex and brainstem of
hypoxic neonatal rats and hypoxic rats supplemented with
glucose and oxygen using binding assays and gene
expression of GABAAa1 and GABAAc5. In the cerebral
cortex and brainstem of hypoxic neonatal rats, a significant
decrease in GABAA receptors was observed, which
accounts for the respiratory inhibition. Hypoxic rats sup-
plemented with glucose alone and with glucose and oxygen
showed, respectively, a reversal of the GABAA receptors,
andGABAAa1 and GABAAc5 gene expression to control.
Glucose acts as an immediate energy source thereby
reducing the ATP-depletion-induced increase in GABA
and oxygenation, which helps in encountering anoxia.
Resuscitation with oxygen alone was less effective in
reversing the receptor alterations. Thus, the results of this
study suggest that reduction in the GABAA receptors
functional regulation during hypoxia plays an important
role in mediating the brain damage. Glucose alone and
glucose and oxygen supplementation to hypoxic neonatal
rats helps in protecting the brain from severe hypoxic
damage.