Radhakrishnan, P; Dr.Sathianandan, K(Cochin University Of Science And Technology, April 30, 1985)
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Abstract:
Laser-induced damage is the principal limiting
constraint in the design and operation of high-power laser
systems used in fusion and other high-energy laser applications.
Therefore, an understanding of the mechanisms
which cause the radiation damage to the components employed
in building a laser and a knowledge of the damage threshold
of these materials are of great importance in designing a
laser system and to operate it without appreciable degradation
in performance. This thesis, even though covers
three distinct problems for investigations using a dye
Q-switched multimode Nd:glass laser operating at 1062 nm
and emitting 25 ns (FWHM) pulses, lays its main thrust on
damage threshold studies on thin films. Using the same glass
laser two-photon excited fluorescence in rhodamine 6G and
generation and characterisation of a carbon plasma have also
been carried out.
Description:
Department of Physics, Cochin University Of Science And Technology
Radhakrishnan, P; Dr.Sathianandan, K(Cochin University of Science and Technology, April 30, 1985)
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Abstract:
Laser-induced damage is the principal limiting constraint in the design and operation of high-power laser systems used in fusion and other high-energy laser applications. Therefore, an understanding of the mechanisms which cause the radiation damage to the components employed
in building a laser and a knowledge of the damage threshold of these materials are of great importance in designing a laser system and to operate it without appreciable degradation in performance. This thesis, even though covers three distinct problems for investigations using a dye Q-switched multimode Nd:glass laser operating at 1062 nm and emitting 25 ns (FWHM) pulses, lays its main thrust on damage threshold studies on thin films. Using the same glass
laser two-photon excited fluorescence in rhodamine 6G and generation and characterisation of a carbon plasma have also been carried out. The thesis is presented in seven chapters.
Description:
Department of Physics, Cochin university of Science and Technology
Anantharaman, M R; Sethulakshmi, N; Al-Omari, I A; Suresh, K G(AIP Publishing, March 5, 2014)
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Abstract:
Nearly half of lanthanum sites in lanthanum manganites were substituted with monovalent
ion-sodium and the compound possessed distorted orthorhombic structure. Ferromagnetic ordering
at 300K and the magnetic isotherms at different temperature ranges were analyzed for estimating
magnetic entropy variation. Magnetic entropy change of 1.5 J kg 1 K 1 was observed near 300 K.
An appreciable magnetocaloric effect was also observed for a wide range of temperatures near
300K for small magnetic field variation. Heat capacity was measured for temperatures lower than
300K and the adiabatic temperature change increases with increase in temperature with a
maximum of 0.62K at 280 K
Mohammed Yusuff, K K; Leeju, P; Arun,V; Manju, Sebastian; Varsha, Gopalakrishnan; Digna, Varghese(Crystallography Journals,Acta Crystallographica Section E ,Structure Reports, July 15, 2009)
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Abstract:
In the title molecule, C16H11N5, the mean planes of the
quinoxaline and indazole fragments form a dihedral angle of
10.62 (5). In the crystal, weak intermolecular N—H..........N
hydrogen bonds link the molecules into zigzag chains
extending in the [001] direction. The crystal packing also
exhibits pye interactions [centroid–centroid distances of
3.7080 (2) and 3.8220 (5) A ˚ ], which form stacks of the
molecules parallel to the a axis
Archana, R; Dr. R Gopikakumari; Dr. A Unnikrishnan(Cochin University of Science and Technology, March 12, 2015)
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Abstract:
Modeling of chaotic systems, based on the output time series, is quite
promising since the output often represents the characteristic behaviour of
the total system. It has been an interesting topic for researchers over the past
few years. So far, some methods are developed for the identification of
chaotic systems. Because of the intense complexity of chaotic systems, the
performance of existing algorithms is not always satisfactory. Application of
chaotic system theory to socially relevant problems like environmental
studies is the need of the hour Neural networks have the required self-learning capability to tune the
network parameters (i.e. weights) for identifying highly non-linear and
chaotic systems. In the present work, effectiveness of modeling a chaotic
system using dynamic neural networks has been demonstrated. From the rich
literature available for non-linear modeling with neural networks, the
Recurrent Neural Network (RNN) structure is selected. The Extended
Kalman Filter (EKF) algorithm is used to train the RNN. Further, the
Expectation Maximization algorithm is used to effectively arrive at the initial
states and the state covariance. Particle filter algorithm with its two important
variants namely Sampling Importance Resampling (SIR) and Rao
Blackwellised algorithms are also used for training the given RNN. Four
standard chaotic systems, Lorenz, Rossler, Chua and Chen, are modelled
with the three algorithms. The best algorithm is found to be EKF-EM based
on the least mean square error criterion. Validation of RNN model with EKFEM
algorithm is done in time domain by Estimation of embedding
dimension, Phase plots, Lyapunov Exponents, Kaplan -Yorke dimension and
Bifurcation diagrams. Analysis of the chaotic systems is also performed in
the transform domain using Fourier, Wavelet and Mapped Real Transforms.
viii
Natural chaotic systems are analyzed based on the selected model structure
and training algorithm, taken for analysis. Sunspot, Venice Lagoon and
North Atlantic oscillations are the three of the natural chaotic systems
modelled with the selected RNN model structure and EKF-EM algorithm.
Dakshinamurti,K; Paulose,C S; Siow,Y L(Department of Biotechnology, 1985)
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Abstract:
Pyridoxal 5'-phosphate (PLP) is the major coenzymatic
form of pyridoxine. There are over one hundred known pyridoxal
5'-phosphate-dependent reactions, most of which are
involved in the metabolism of various amino acids . Pyridoxamine
5'-phosphate can function in aminotransf erase reactions
by the cyclic regeneration of the two active phosphate
forms. Pyridoxal 5'-phosphate-dependent reactions studied
in the nervous system are involved in the catabolism of various
amino acids. The putative neurotransmitters , dopamine,
norepinephrine , serotonin , histamine , aminobutyric acid
and taurine , as well as the sphingoiipids and poly amines are
synthesized by PLP-dependent enzymes. Of these enzymes,
three ( glutamic acid decarboxylase , 5-hydroxytryptophan decarboxylase
and crnithine decarboxylase) seem to have crucial
roles (Fig. '). The clinical effects of pyridoxine deficiency
can be explained on the basis of the known decreases
in the activities of these enzymes
Dakshinamurti,K; Paulose,C S; Viswanathan,M; Siow,Y L(Department of Biotechnology, 1988)
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Abstract:
Veuruenducrim lri v j p .rim,
deficienc:v. NEUROSCI BIOBEHAV REV 12(3/4) 189-193. 1988.- Dihydroxyphenylalanine decarboxvlase and
5-hydroxytryptophan decarboxvlase respectively have high and low affinities for pyridoxal phosphate. In the pyridoxinedeficient
animal. hypothalamic serotonin content is significantly reduced without any change in catecholamine levels.
Hypothalamic neurotransmitters affect the hvpothalamo-pituitary-end organ axes. Specifically, the decrease in hypothalamic
serotonin in the pyridoxine-deficient rat results in tertiary hypothyroidism. In addition. pineal function is affected in
deficient animals due to decreased synthesis of melatonin.
Anitha, M; Dr. Paulose, C S(Cochin University of Science and Technology, July , 2012)
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Abstract:
This thesis Entitled Neuronal degeneration in streptozotocin induced diabetic rats: effect of aegle marmelose and pyridoxine in pancreatic B cell proliferation and neuronal survival. Diabetes mellitus, a chronic metabolic disorder results in neurological dysfunctions and structural changes in the CNS. Antioxidant therapy is a challenging but necessary dimension in the management of diabetes and neurodegenerative changes associated with it. Our results showed regional variation and imbalance in the expression pattern of dopaminergic receptor subtypes in diabetes and its role in imbalanced insulin signaling and glucose regulation. Disrupted dopaminergic signaling and increased hyperglycemic stress in diabetes contributed to the neuronal loss. Neuronal loss in diabetic rats mediated through the expression of pattern of GLUT-3, CREB, IGF-1, Akt-1, NF,B, second messengers- cAMP, cGMP, IP3 and activation of apoptotic factors factors- TNF-a,caspase-8. Disrupted dopaminergic receptor expressions and its signaling in pancreas contributed defective insulin secretion in diabetes. Activation of apoptotic factors- TNF- a,caspase-8 and defective functioning of neuronal survival factors, disrupted second messenger signaling modulated neuronal viability in diabetes. Hyperglycemic stress activated the expression of TNF-a,caspase-8, BAX and differential expression of anti oxidant
enzymes- SOD and GPx in liver lead to apoptosis. Treatment of diabetic rats with insulin, Aegle marmelose and pyridoxine significantly reversed the altered dopaminergic neurotransmission, GLUT3, GLUT2, IGF-1 and second messenger signaling. Antihyperglycemic and antioxidant activity of Aegle marmelose and pyridoxine enhanced pancreatic B cell proliferation, increased insulin synthesis and secretion in diabetic rats. Thus our results conclude the neuroprotective and regenerating ability of Aegle marmelose and pyridoxine which in turn has a novel therapeutic role in the management of diabetes.
Description:
Center for neuroscience, Department of Biotechnology, Cochin University of Science and Technology
Paulose,C S; Amee,Krishnakumar; Anu, Joseph(Department of Biotechnology, 2007)
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Abstract:
Neuroscience is the study of'tbe ne rvous system , including the i - ; . in, spinal
cord and peripheral nerves . Neurons are the basic cells of the brain and
nervous system which exerts its functional role through various
neurotransmitters and receptor systems . The activity of a nen ren depends
on the balance between the number of excitatory and inhibito r y processes
affecting it, both processes occurring individually and sin ,tlte-' ,ieously. The
functional bal,ince of different neurotransmitters such as Acct >>lcholine
(Ach), Dopamine (DA), Serotonin (5-1-17), Nor epinepbri,te (N.1 j,
Epinephrine (LPI), Glutamate and Gamma amino butyric acid (GA BA)
regulates the growth , division and other vital functions ofa normal cell /
organisin (Sudha, 1 998). The micro-environ ; nertt of the cell is controlled
/ the macro-environment that surrounds the individual. Any change in
the cell environment causes imbalance in cell homeostasis and f,ntction.
Pollution is a significant cause of imbalance caused iii the inacYcenvironment.
Interaction with polluted environments can have an adverse
impact on the health of humans. The alarming rise in enviromilmieil
cont.iniin :rtion has been linked to rises in levels of pesticides, ndltstr al
effluents, domestic Waste, car exhausts and other anthropogenic activities.
Persistent exposures to contaminant cause a negative imp,-, on brain
health and development . Pollution also causes a change in the
neurotransmitters and their receptor function leading to earl.;' recurrence
of neurodcge,terative disorders such as flypoxia , Alzbeimers's and
Huntington 's disease early in life.
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.
Shiny,Palaty; Dr.Rani,Joseph(Cochin University of Science And Technology, March , 2002)
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Abstract:
The primary objective of this work is to develop an efficient accelerator system
for low temperature vulcanization of rubbers. Although xanthates are known to act as
accelerators for low temperature vulcanization, a systematic study on the mechanism
of vulcanization, the mechanical properties of the vulcanizates at varying temperatures
of vulcanization, cure characteristics etc are not reported. Further. xanthate based
curing systems are not commonly used because of their chance for premature
vulcanization during processing. The proposed study is to develop a novel accelerator
system for the low temperature vulcanization of rubbers having enough processing
safely. lt is also proposed to develop a method for the prevulcanisation of natural
rubber latex at room temperature.
As already mentioned the manufacture of rubber products at low
temperature will improve its quality and appearance. Also, energy consumption can
be reduced by low temperature vulcanization. in addition, low temperature
vulcanization will be extremely useful in the area of repair of defective products,
since subjecting finished products to high temperatures during the process of repair
will adversely affect the quality of the product. Further. room temperature curing
accelerator systems will find extensive applications in surface coating industries.
Description:
Department of Polymer science & Rubber Technology, Cochin University of Science And Technology
Supriyo,Dey; Aanandan,C K; Mohanan, P; K G Nair(Microwave and Optical Technology Letters, September , 1994)
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Abstract:
A simple technique to improve the impedance bandwidth of a circular
microstrip patch antenna using two sectorial slots is proposed. Using this
design more than 5% impedance bandwidth is obtained. The added
advantage of this new antenna is that it can be fed by a 50- microstrip line
Aanandan,C K; Mohanan, P; Supriyo,Dey; K G Nair(Department of Electronics, 1994)
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Abstract:
A simple technique to improve the impedance bandwidth of a circular
microstrip patch antenna using two sectorial slots is proposed. Using this
design more than 5% impedance bandwidth is obtained. The added
advantage of this new antenna is that it can be fed by a 50 microstrip
line.