Navya, Antony; Dr.Mohanan, P V(Cochin University of Science And Technology, March 25, 2014)
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Abstract:
Several natural and synthetic supports have been assessed for their efficiency
for enzyme immobilization. Synthetic polymer materials are prepared by chemical
polymerization using various monomers. As a kind of important carrier, synthetic
polymer materials exhibit the advantages of good mechanical rigidity, high specific
surface area, inertness to microbial attack, easy to change their surface characteristics,
and their potential for bringing specific functional group according to actual needs.
Hence, they have been widely investigated and used for enzyme immobilization.
When it comes to the natural polymer materials, much attention has been paid
to cellulose and other natural polymer materials owing to their wide range of sources,
easy modification, nontoxic, and pollution-free, with a possibility of introducing wide
variety of functional groups and good biocompatible properties.
In this work report the use of synthetic polymer, polypyrrole and its
derivatives and natural polymers coconut fiber and sugarcane bagasse as supports for
Diastase α- amylase immobilization. An attempt was also made to functionalize both
synthetic and natural polymers using Amino-propyl triethoxysilane. Supports and their
immobilized forms were characterized via FT-IR, TG, SEM, XRD, BET and EDS
techniques. Immobilization parameters were also optimized so as to prepare stable
immobilized biocatalyst for starch hydrolysis.
Description:
Department of Applied Chemistry
Cochin University of Science and Technology
Babu,S; Dr.Krishnamoorthy,A(Cochin University of Science and Technology, May , 2007)
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Abstract:
In this thesis we have studied a few models involving self-generation of priorities.
Priority queues have been extensively discussed in literature. However, these are situations involving priority assigned to
(or possessed by) customers at the time of their arrival. Nevertheless, customers
generating into priority is a common phenomena. Such situations especially arise
at a physicians clinic, aircrafts hovering over airport running out of fuel but waiting
for clearance to land and in several communication systems. Quantification of these
are very little seen in literature except for those cited in some of the work indicated
in the introduction. Our attempt is to quantify a few of such problems. In doing
so, we have also generalized the classical priority queues by introducing priority
generation ( going to higher priorities and during waiting). Systematically we have
proceeded from single server queue to multi server queue. We also introduced customers with repeated attempts (retrial) generating
priorities. All models that were analyzed in this thesis involve nonpreemptive
service. Since the models are not analytically tractable, a large number
of numerical illustrations were produced in each chapter to get a feel about the
working of the systems.
Description:
Department of Mathematics,
Cochin University of Science and Technology
Venu, Nair G; Dr.Mohan Kumar, K(Department of Atmospheric Science, 2006)
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Abstract:
The thesis gives a general introduction about the topic include India, the spatial and temporal variation of the surface meteorological parameters are dealt in detail. The general pattern of the winds over the region in different seasons and the generation and movements of the thermally and dynamically originated local wind systems of Western Ghats region has been studied. The modification of the prevailing winds over region by the Palghat Gap and its effect on the mouth regions pf the gap is analysed in great depth. The thesis gives the information of climatic elements of the mountain region such as energy budgets, rainfall studies, evaporation and condensation and the variation in the heat fluxes over the region. The impact of orography is studied in a different approach. The type of hypothetical study gives more insight into the control of mountain on the distribution of meteorological parameter over the study region and helps to quantify the impact of the mountain in varying the weather climate of region. The detailed study of the hydro-meteorological aspects of the main river basins of the region also should be included to the climatic studies for the total understanding of the weather and climate over the region.
Nelson, Rodrigues; Dr. Jacob, Philip(Cochin University of Science and Technology, March , 1997)
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Abstract:
The dielectric and elastic properties are of considerable significance to the science and
technology of matter in the solid state. The study of these properties give information
about the magnitude of the forces and nature of the bonding between the atoms. Our
aim has been to investigate systematically the effect of doping of an appropriate element
on the elastic and dielectric properties of selected dielectric ceramics and oxide glasses.
These materials have got wide technological applications due to their interesting electrical, optical, thermal and elastic behaviour. Ultrasound propagation and capacitance
measurement techniques have been employed for the systematic investigation of the
elastic and dielectric properties of selected number of these materials. Details of the
work done and results obtained are presented in this thesis.
Description:
Department of Physics, Cochin
University of Science and Technology
Rachel, Reena Philip; Dr.Pradeep, B(Cochin University of Science And Technology, December , 2004)
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Abstract:
Investigations on thin films that started decades back due to scientific curiosity in the
properties of a two-dimensional solid, has developed into a leading research field in
recent years due to the ever expanding applications of the thin films in the fann of a
variety of active and passive microminiaturized components and devices, solar cells,
radiation sowces and detectors, magnetic memory devices, interference filters,
refection and antireflection coatings etc. [1]. The recent environment and energy
resource concerns have aroused an enonnous interest in the study of materials in thin
film form suitable for renewable energy sources such as photovoltaic devices.
Recognition of the immense potential applications of the chalcopyrites that can fonn
homojunctions or heterojunctions for solar cell fabrication has attracted many
researchers to extensive and intense research on them.
In this thesis, we have started with studies performed on CuInSe, thin films, a
technologically well recognized compound belonging to the l•ill-VI family of
semiconductors and have riveted on investigations on the preparation and
characterization of compoWlds Culn3Se5. Culn5Seg and CuIn7Se12, an interesting group
of compounds related to CuInSe2 called Ordered Vacancy Compounds, having
promising applications in photovoltaic devices. A pioneering work attempted on
preparing and characterizing the compound Culn7Sel2 is detailed in the chapters on
OVC's. Investigation on valence band splitting in avc's have also been attempted for
the first time and included as the last chapter in the thesis. Some of the salient features
of the chalcopyrite c.ompounds are given in the next section .of this introductory
chapter.
Description:
Department of Physics, Cochin University of Science And Technology,
Antu K, Antony; Raghu, K G(Cochin University of Science and Technology, December , 2014)
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Abstract:
Diabetes mellitus is a heterogeneous metabolic disorder characterized by hyperglycemia
with disturbances in carbohydrate, protein and lipid metabolism resulting from defects in
insulin secretion, insulin action or both. Currently there are 387 million people with
diabetes worldwide and is expected to affect 592 million people by 2035. Insulin
resistance in peripheral tissues and pancreatic beta cell dysfunction are the major
challenges in the pathophysiology of diabetes. Diabetic secondary complications (like
liver cirrhosis, retinopathy, microvascular and macrovascular complications) arise from
persistent hyperglycemia and dyslipidemia can be disabling or even life threatening.
Current medications are effective for control and management of hyperglycemia but
undesirable effects, inefficiency against secondary complications and high cost are still
serious issues in the present prognosis of this disorder. Hence the search for more
effective and safer therapeutic agents of natural origin has been found to be highly
demanding and attract attention in the present drug discovery research. The data
available from Ayurveda on various medicinal plants for treatment of diabetes can
efficiently yield potential new lead as antidiabetic agents. For wider acceptability and
popularity of herbal remedies available in Ayurveda scientific validation by the
elucidation of mechanism of action is very much essential. Modern biological techniques
are available now to elucidate the biochemical basis of the effectiveness of these
medicinal plants. Keeping this idea the research programme under this thesis has been
planned to evaluate the molecular mechanism responsible for the antidiabetic property of
Symplocos cochinchinensis, the main ingredient of Nishakathakadi Kashayam, a wellknown
Ayurvedic antidiabetic preparation. A general introduction of diabetes, its
pathophysiology, secondary complications and current treatment options, innovative
solutions based on phytomedicine etc has been described in Chapter 1.
The effect of Symplocos cochinchinensis (SC), on various in vitro biochemical targets
relevant to diabetes is depicted in Chapter 2 including the preparation of plant extract.
Since diabetes is a multifactorial disease, ethanolic extract of the bark of SC (SCE) and its
fractions (hexane, dichloromethane, ethyl acetate and 90 % ethanol) were evaluated by in
vitro methods against multiple targets such as control of postprandial hyperglycemia,
insulin resistance, oxidative stress, pancreatic beta cell proliferation, inhibition of protein
glycation, protein tyrosine phosphatase-1B (PTP-1B) and dipeptidyl peptidase-IV (DPPxxi
IV). Among the extracts, SCE exhibited comparatively better activity like alpha
glucosidase inhibition, insulin dependent glucose uptake (3 fold increase) in L6
myotubes, pancreatic beta cell regeneration in RIN-m5F and reduced triglyceride
accumulation in 3T3-L1 cells, protection from hyperglycemia induced generation of
reactive oxygen species in HepG2 cells with moderate antiglycation and PTP-1B
inhibition. Chemical characterization by HPLC revealed the superiority of SCE over other
extracts due to presence of bioactives (beta-sitosterol, phloretin 2’glucoside, oleanolic
acid) in addition to minerals like magnesium, calcium, potassium, sodium, zinc and
manganese. So SCE has been subjected to oral sucrose tolerance test (OGTT) to evaluate
its antihyperglycemic property in mild diabetic and diabetic animal models. SCE showed
significant antihyperglycemic activity in in vivo diabetic models.
Chapter 3 highlights the beneficial effects of hydroethanol extract of Symplocos
cochinchinensis (SCE) against hyperglycemia associated secondary complications in
streptozotocin (60 mg/kg body weight) induced diabetic rat model. Proper sanction had
been obtained for all the animal experiments from CSIR-CDRI institutional animal ethics
committee. The experimental groups consist of normal control (NC), N + SCE 500 mg/kg
bwd, diabetic control (DC), D + metformin 100 mg/kg bwd, D + SCE 250 and D + SCE
500. SCEs and metformin were administered daily for 21 days and sacrificed on day 22.
Oral glucose tolerance test, plasma insulin, % HbA1c, urea, creatinine, aspartate
aminotransferase (AST), alanine aminotransferase (ALT), albumin, total protein etc. were
analysed. Aldose reductase (AR) activity in the eye lens was also checked. On day 21,
DC rats showed significantly abnormal glucose response, HOMA-IR, % HbA1c,
decreased activity of antioxidant enzymes and GSH, elevated AR activity, hepatic and
renal oxidative stress markers compared to NC. DC rats also exhibited increased level of
plasma urea and creatinine. Treatment with SCE protected from the deleterious alterations
of biochemical parameters in a dose dependent manner including histopathological
alterations in pancreas. SCE 500 exhibited significant glucose lowering effect and
decreased HOMA-IR, % HbA1c, lens AR activity, and hepatic, renal oxidative stress and
function markers compared to DC group. Considerable amount of liver and muscle
glycogen was replenished by SCE treatment in diabetic animals. Although metformin
showed better effect, the activity of SCE was very much comparable with this drug.
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The possible molecular mechanism behind the protective property of S. cochinchinensis
against the insulin resistance in peripheral tissue as well as dyslipidemia in in vivo high
fructose saturated fat diet model is described in Chapter 4. Initially animal were fed a
high fructose saturated fat (HFS) diet for a period of 8 weeks to develop insulin resistance
and dyslipidemia. The normal diet control (ND), ND + SCE 500 mg/kg bwd, high
fructose saturated fat diet control (HFS), HFS + metformin 100 mg/kg bwd, HFS + SCE
250 and HFS + SCE 500 were the experimental groups. SCEs and metformin were
administered daily for the next 3 weeks and sacrificed at the end of 11th week. At the end
of week 11, HFS rats showed significantly abnormal glucose and insulin tolerance,
HOMA-IR, % HbA1c, adiponectin, lipid profile, liver glycolytic and gluconeogenic
enzyme activities, liver and muscle triglyceride accumulation compared to ND. HFS rats
also exhibited increased level of plasma inflammatory cytokines, upregulated mRNA
level of gluconeogenic and lipogenic genes in liver. HFS exhibited the increased
expression of GLUT-2 in liver and decreased expression of GLUT-4 in muscle and
adipose. SCE treatment also preserved the architecture of pancreas, liver, and kidney
tissues. Treatment with SCE reversed the alterations of biochemical parameters, improved
insulin sensitivity by modifying gene expression in liver, muscle and adipose tissues.
Overall results suggest that SC mediates the antidiabetic activity mainly via alpha
glucosidase inhibition, improved insulin sensitivity, with antiglycation and antioxidant
activities.
Priya Rani, M; Dr. Padmakumari Amma, K. P.; Dr. Raghu, K. G.(Cochin University of Science & Technology, June , 2014)
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Abstract:
Plants and microorganisms provide the pharmaceutical industry with some of the most important sources of components for the research of new medications This thesis involves the study of three medicinal plants belonging to three different important families viz, Cyperus rotundus (Cyperaceae), Stereospermum colais (Bignoniaceae) as well as the well known medicinal plant Zingiber officinale (Zingiberaceae) as the third. The first chapter gives an overview of biologically active natural products with special reference to antioxidant, antidiabetic, anti-inflammatory and antimicrobial molecules from terrestrial sources. Chapter 2 of the thesis deals with the isolation of phytochemical constituents of the medicinal plant Cyperus rotundus and its antioxidant and radical scavenging potential. Chapter 3 of the thesis describes the studies on the roots of Stereospermum colais,
A Bignoniaceae plant belonging to the genus Stereospermum which is used extensively. Chapter 3 of the thesis describes the studies on the roots of Stereospermum colais, a Bignoniaceae plant belonging to the genus Stereospermum which is used extensively in Ayurveda. Chapter 4 describes the biological potential of rhizomes of Zingiber officinale. Ethyl acetate extract of ginger (EAG) possessed antioxidant activity as is evident from the results of various in vitro assays compared to other extracts .In conclusion, medicinal plants Cyperus rotundus and Stereospermum colais have been analysed for their phytochemical constituents. Also, the positive results obtained from biological activity studies such as antioxidant, anti-inflammatory and antimicrobial activity on the isolated compounds/extracts add on to the medicinal properties of these plants. Apart from that, ethyl acetate extract of Zingiber officinale (ginger) rhizomes has been shown to have very good biological potential including glucose lowering and adipocyte differentiation inhibitory effect.
Sobha, A; Dr.Syamaprasad,U(Cochin University of Science And Technology, December , 2002)
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Abstract:
It is important that long superconducting tape must have
desired strain tolerance (less reduction of Jc with applied strains) and
stress tolerance (less reduction of JC in applied stresses) for its use as
coils and magnets. Ag addition to the BPSCCO system has many
advantages with its physical and chemical inertness to the system,
reduces the processing temperature, and promotes the grain growth,
grain alignment and connectivity. All these not only enhance the
critical current density of the tapes but also improve the mechanical
properties. But the published results show very much scattering on the
type of Ag additive to be selected, method of addition and its optimum
percentage. Also there are some negative reports in this regard. The
present work has been undertaken to study the effect of silver addition
in different forms (Ag powder, Ag2O, AgNO3) on the superconducting
and mechanical properties of (Bi,Pb)-2223/Ag tapes and to find out a
suitable form of Ag additive and its optimum percentage to have better
superconducting and mechanical properties. Also it is the aim of the
present work is to optimise the process parameters needed to prepare
(Bi,Pb)-2223/Ag multifilamentary tapes of length ~ 12 m in solenoid
and pancake coil forms with good critical current density and
homogeneity of J C along the length of the tapes.
Description:
Department of physics, Cochin University of Science And Technology
Radhakrishnan, M K; Dr.Joy, George(Cochin University of Science And Technology, February , 1981)
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Abstract:
The Thesis consist of the study of the electrical properties of antimony trisulphide films and the electrical behaviour of different metal contacts to antimony trisulphide films. Since the thermal evapouration of the compound antimony trisulphide as such mayresult in nonstoichiometric compound films , sb2s3 films in the present work were mostly prepared by the three temperature method ,keeping the substrate at different temperature ranging from 3031 to 4231 and evapourating antimony and sulphur simultaneously from separate sources.
Description:
Department of Physics, Cochin University of Science And Technology
Urmila, K. S; Dr. Pradeep, B.(Cochin University of Science and Technology, August 6, 2016)
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Abstract:
The use of energy in our day to day life has grown exponentially and
conserving energy to meet the world’s escalating energy demands is the need of
the hour. During the past decade there is a heightened awareness all over the
world that the production costs of energy from coal, oil and natural gas is
increasingly higher and at the same time the energy technologies involving their
use are contributing to a serious rise in the greenhouse gases in the environment
and a consequent global warming. As a result, more attention is focused on the
utilization of clean energy technologies, especially solar energy which has a
great potential to meet a large fraction of world’s energy demands using
photovoltaics (PV). The heart of the PV system that efficiently convert sunlight
directly into electricity through photovoltaic effect is the solar cell - originally
developed for space applications in the 1950s, are now used in consumer
products, mounted on roofs of houses or assembled into large power stations.