Sobhana, Mathew; Dr.Girish Kumar, K(Cochin University of Science and Technology, March , 2012)
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Abstract:
Electroanalytical techniques represent a class of powerful and versatile
analytical method which is based on the electrical properties of a solution of
the analyte when it is made part of an electrochemical cell. They offer high
sensitivity, accuracy, precision and a large linear dynamic range. The cost of
instrumentation is relatively low compared to other instrumental methods of
analysis. Many solid state electrochemical sensors have been commercialised
nowadays. Potentiometry is a very simple electroanalytical technique with
extraordinary analytical capabilities. Since valinomycin was introduced as an
ionophore for K+, Ion Selective Electrodes have become one of the best
studied and understood analytical devices. It can be used for the
determination of substances ranging from simple inorganic ions to complex
organic molecules. It is a very attractive option owing to the wide range of
applications and ease of the use of the instruments employed. They also
possess the advantages of short response time, high selectivity and very low
detection limits. Moreover, analysis by these electrodes is non-destructive and
adaptable to small sample volumes. It has become a standard technique for
medical researchers, biologists, geologists and environmental specialists.
This thesis presents the synthesis and characterisation of five
ionophores. Based on these ionophores, nine potentiometric sensors are
fabricated for the determination of ions such as Pb2+, Mn2+, Ni2+, Cu2+ and
Sal- ion (Salicylate ion). The electrochemical characterisation and analytical
application studies of the developed sensors are also described. The thesis is
divided into eight chapters
Description:
Department of Applied Chemistry, Cochin University of Science and Technology
Kishore,V C; Dr.Sudha Kartha,C; Dr. Sreekumar, K(Cochin University of Science & Technology, June , 2008)
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Abstract:
This Thesis discussed molecules suitable for photorefractive effect. Out
of the molecules studied, only one system was used to make photorefractive polymers system. Other molecules, especially, the electro-optic
polymer, Poly(3-methacrloyl-1-(4'-nitro-4-azo-1'-phenyl)phenylalanine-co-
methyl methacrylate) can be subjected to more detailed studies to explore
the possibilities of using them for electro-optic applications. Though not included in the thesis, the efficient photoconductor, Poly(6-tert-butyl-3-
phenyl-3,4-dihydro-2H-1,3-benzoxazine) sensitized with C60, which was described in Chapter 3 showed a low magnitude photovoltaic effect. This
hints at the possibility of using this system for organic solar cells also. The thesis presented the initial observation of photorefractive effect in
a polybenzoxazine based polymer system. A detailed analysis of the effect of C60, ECZ and DR1 can be carried out to check for the possibility of a high efficiency photorefractive system.
Description:
Applied Optics Division, Department of Physics, Cochin University of Science and Technology
Sanal, K C; Dr.Jayaraj, M K(Cochin University of Science And Technology, January 27, 2014)
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Abstract:
Semiconductor physics has developed significantly in the field of re-
search and industry in the past few decades due to it’s numerous
practical applications. One of the relevant fields of current interest in
material science is the fundamental aspects and applications of semi-
conducting transparent thin films. Transparent conductors show the
properties of transparency and conductivity simultaneously. As far
as the band structure is concerned, the combination of the these two
properties in the same material is contradictory. Generally a trans-
parent material is an insulator having completely filled valence and
empty conduction bands. Metallic conductivity come out when the
Fermi level lies within a band with a large density of states to provide
high carrier concentration. Effective transparent conductors must nec-
essarily represent a compromise between a better transmission within the visible spectral range and a controlled but useful electrical con-
ductivity [1–6]. Generally oxides like In2O3, SnO2, ZnO, CdO etc,
show such a combination. These materials without any doping are
insulators with optical band gap of about 3 eV. To become a trans-
parent conductor, these materials must be degenerately doped to lift
the Fermi level up into the conduction band. Degenerate doping pro-
vides high mobility of extra carriers and low optical absorption. The
increase in conductivity involves an increase in either carrier concen-
tration or mobility. Increase in carrier concentration will enhance the
absorption in the visible region while increase in mobility has no re-
verse effect on optical properties. Therefore the focus of research for
new transparent conducting oxide (TCO) materials is on developing
materials with higher carrier mobilities.
Description:
Department of Physics
Cochin University of Science and Technology
Sreekumar, A; Dr.Vijayakumar, K P(Cochin University of Science And Technology, November , 2007)
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Abstract:
In the present work, the author has designed and developed all types of solar
air heaters called porous and nonporous collectors. The developed solar air
heaters were subjected to different air mass flow rates in order to standardize
the flow per unit area of the collector. Much attention was given to
investigate the performance of the solar air heaters fitted with baffles. The
output obtained from the experiments on pilot models, helped the installation
of solar air heating system for industrial drying applications also. Apart from
these, various types of solar dryers, for small and medium scale drying
applications, were also built up. The feasibility of ‘latent heat thermal energy
storage system’ based on Phase Change Material was also undertaken. The
application of solar greenhouse for drying industrial effluent was analyzed in
the present study and a solar greenhouse was developed. The effectiveness
of Computational Fluid Dynamics (CFD) in the field of solar air heaters was
also analyzed. The thesis is divided into eight chapters.
Description:
Department of Physics, Cochin University of Science and Technology
Sooraj,K P; Rajan,C K(Department of Atmospheric Sciences, 2004)
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Abstract:
This study focuses on the onset of southwest monsoon over Kerala. India Meteorological Department (IMD) has been using a semi-objective method to define monsoon onset. The main objectives of the study are to understand the monsoon onset processes, to simulate monsoon onset in a GCM using as input the atmospheric conditions and Sea Surface Temperature, 10 days earlier to the onset, to develop a method for medium range prediction of the date of onset of southwest monsoon over Kerala and to examine the possibility of objectively defining the date of Monsoon Onset over Kerala (MOK). It gives a broad description of regional monsoon systems and monsoon onsets over Asia and Australia. Asian monsoon includes two separate subsystems, Indain monsoon and East Asian monsoon. It is seen from this study that the duration of the different phases of the onset process are dependent on the period of ISO. Based on the study of the monsoon onset process, modeling studies can be done for better understanding of the ocean-atmosphere interaction especially those associated with the warm pool in the Bay of Bengal and the Arabian Sea.
Linda, Louis; Sarita, Bhat G(Cochin University Of Science And Technology, December , 2014)
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Abstract:
The resurgence of the enteric pathogen Vibrio cholerae, the causative organism of epidemic cholera, remains a major health problem in many developing countries like India. The southern Indian state of Kerala is endemic to cholera. The outbreaks of cholera follow a seasonal pattern in regions of endemicity. Marine aquaculture settings and mangrove environments of Kerala serve as reservoirs for V. cholerae. The non-O1/non-O139 environmental isolates of V. cholerae with incomplete ‘virulence casette’ are to be dealt with caution as they constitute a major reservoir of diverse virulence genes in the marine environment and play a crucial role in pathogenicity and horizontal gene transfer. The genes coding cholera toxin are borne on, and can be infectiously transmitted by CTXΦ, a filamentous lysogenic vibriophages. Temperate phages can provide crucial virulence and fitness factors affecting cell metabolism, bacterial adhesion, colonization, immunity, antibiotic resistance and serum resistance. The present study was an attempt to screen the marine environments like aquafarms and mangroves of coastal areas of Alappuzha and Cochin, Kerala for the presence of lysogenic V. cholerae, to study their pathogenicity and also gene transfer potential. Phenotypic and molecular methods were used for identification of isolates as V. cholerae. The thirty one isolates which were Gram negative, oxidase positive, fermentative, with or without gas production on MOF media and which showed
yellow coloured colonies on TCBS (Thiosulfate Citrate Bile salt Sucrose) agar were segregated as vibrios. Twenty two environmental V. cholerae strains of both O1 and non- O1/non-O139 serogroups on induction with mitomycin C showed the presence of lysogenic phages. They produced characteristic turbid plaques in double agar overlay assay using the indicator strain V. cholerae El Tor MAK 757. PCR based molecular typing with primers targeting specific conserved sequences in the bacterial genome, demonstrated genetic diversity among these lysogen containing non-O1 V. cholerae . Polymerase chain reaction was also employed as a rapid screening method to verify the presence of 9 virulence genes namely, ctxA, ctxB, ace, hlyA, toxR, zot,tcpA, ninT and nanH, using gene specific primers. The presence of tcpA gene in ALPVC3 was alarming, as it indicates the possibility of an epidemic by accepting the cholera. Differential induction studies used ΦALPVC3, ΦALPVC11, ΦALPVC12 and ΦEKM14, underlining the possibility of prophage induction in natural ecosystems, due to abiotic factors like antibiotics, pollutants, temperature and UV. The efficiency of induction of prophages varied
considerably in response to the different induction agents. The growth curve of lysogenic V. cholerae used in the study drastically varied in the presence of strong prophage inducers like antibiotics and UV. Bacterial cell lysis was directly proportional to increase in phage number due to induction. Morphological characterization of vibriophages by Transmission Electron Microscopy revealed hexagonal heads for all the four phages. Vibriophage ΦALPVC3 exhibited isometric and contractile tails characteristic of family Myoviridae, while phages ΦALPVC11 and ΦALPVC12 demonstrated the typical hexagonal head and non-contractile tail of family Siphoviridae. ΦEKM14, the podophage was distinguished by short non-contractile tail and icosahedral head. This work demonstrated that environmental parameters can influence the viability and cell adsorption rates of V. cholerae phages. Adsorption studies showed 100% adsorption of ΦALPVC3 ΦALPVC11, ΦALPVC12 and ΦEKM14 after 25, 30, 40 and 35 minutes respectively. Exposure to high temperatures ranging from 50ºC to 100ºC drastically reduced phage viability. The optimum concentration of NaCl required for survival of vibriophages except ΦEKM14 was 0.5 M and that for ΦEKM14 was 1M NaCl. Survival of phage particles was maximum at pH 7-8. V. cholerae is assumed to have existed long before their human host and so the pathogenic clones may have evolved from aquatic forms which later colonized the human intestine by progressive acquisition of genes. This is supported by the fact that the vast majority of V. cholerae strains are still part of the natural aquatic environment. CTXΦ has played a critical role in the evolution of the pathogenicity of V. cholerae as it can transmit the ctxAB gene. The unusual transformation of V. cholerae strains associated with epidemics and the emergence of V. cholera O139 demonstrates the evolutionary success of the organism in attaining greater fitness. Genetic changes in pathogenic V. cholerae constitute a natural process for developing immunity within an endemically infected population. The alternative hosts and lysogenic environmental V. cholerae strains may potentially act as cofactors in promoting cholera phage ‘‘blooms’’ within aquatic environments, thereby influencing transmission of phage sensitive, pathogenic V. cholerae strains by aquatic vehicles. Differential induction of the phages is a clear indication of the impact of environmental pollution and global changes on phage induction. The development of molecular biology techniques offered an accessible gateway for investigating the molecular events leading to genetic diversity in the marine environment. Using nucleic acids as targets, the methods of fingerprinting like ERIC PCR and BOX PCR, revealed that the marine environment harbours potentially pathogenic group of bacteria with genetic diversity. The distribution of virulence associated genes in the environmental isolates of V. cholerae provides tangible material for further investigation. Nucleotide and protein sequence analysis alongwith protein structure prediction aids in better understanding of the variation inalleles of same gene in different ecological niche and its impact on the protein structure for attaining greater fitness of pathogens. The evidences of the co-evolution of virulence genes in toxigenic V. cholerae O1 from different lineages of environmental non-O1 strains is alarming. Transduction studies would indicate that the phenomenon of acquisition of these virulence genes by lateral gene transfer, although rare, is not quite uncommon amongst non-O1/non-O139 V. cholerae and it has a key role in diversification. All these considerations justify the need for an integrated approach towards the development of an effective surveillance system to monitor evolution of V. cholerae strains with epidemic potential. Results presented in this study, if considered together with the mechanism proposed as above, would strongly suggest that the bacteriophage also intervenes as a variable in shaping the cholera bacterium, which cannot be ignored and hinting at imminent future epidemics.
Description:
Microbial Genetics laboratory,
Department of Biotechnology
Thresiamma,T K; Dr.Wazir, Hasan Abdi(Cochin University of Science and Technology, 1985)
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Abstract:
The object of this thesis is to formulate a basic commutative difference operator theory for
functions defined on a basic sequence, and a bibasic commutative difference operator theory for functions defined on a bibasic sequence of points, which can be applied to the solution of basic and bibasic difference equations. in this thesis a brief survey of the work done in this field in the classical case, as well as a review of the development of q~difference equations, q—analytic function theory, bibasic analytic function theory, bianalytic function theory, discrete pseudoanalytic function theory and finally a summary of results of this thesis
Description:
Department of Mathematics and
Statistics, Cochin University of Science & Technology
Deepthi, C P; Dr.Krishnamoorthy,A(Cochin University of Science and Technology, May 3, 2013)
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Abstract:
In everyday life different flows of customers to avail some service facility or other at some service station are experienced. In some of these situations, congestion of items arriving for service, because an item cannot be serviced Immediately on arrival, is unavoidable. A queuing system can be described as customers arriving for service, waiting for service if it is not immediate, and if having waited for service, leaving the system after being served. Examples Include shoppers waiting in front of checkout stands in a supermarket, Programs waiting to be processed by a digital computer, ships in the harbor Waiting to be unloaded, persons waiting at railway booking office etc. A queuing system is specified completely by the following characteristics: input or arrival pattern, service pattern, number of service channels, System capacity, queue discipline and number of service stages. The ultimate objective of solving queuing models is to determine the characteristics that measure the performance of the system
Description:
Department
of Mathematics, Cochin University of Science and Technology
Rapheal,P F; Prathapachandra Kurup, M R(Department of applied chemistry, 2006)
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Abstract:
The study deals with the diversity in structural and spectural characteristics of some transition metal complexes derived from aldehyde based thiosemicarbazone ligands thiosemicarbazones are a family of compounds with beneficial biological activity viz., anticancer,antitumour, antifungal, antibacterial, antimalarial, antifilarial, antiviral and anti-HIV activities. Many thiosemicarbazone ligands and their complexes have been prepared and screened for their antimicrobial activity against various types of fungi and bacteria. The results prove that the compounds exhibit antimicrobial properties and it is important to note that in some cases metal chelates show more inhibitory effects than the parent ligands. The increased lipophilicity of these complexes seems to be responsible for their enhanced biological potency. Adverse biological activities of thiosemicarbazones have been widely studied in rats and in other species. The parameters measured show that copper complexes caused considerable oxidative stress and zinc zinc complexes behaved as antioxidants. It has applications on analytical field also. Some thiosemicarbazones produce highly colored complexes with metal ions. This thesis aims to synthesis some novel thiosemicarbazone ligands and their transition metal complexes together with their physico-chemical characterization.
Leeju, P; Dr.Mohammed Yusuff,K K(Cochin University of Science & Technology, April , 2011)
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Abstract:
In this thesis we report the synthsis and characterisation of new transition metal complexes of Pd(II),Cu(II),Ru(II) and Ir(III) of Schiff bases derived from quinoxaline-2-carboxaldehyde/3-hydroxyquinoxaline-2-carboxaldehyde and 5-aminoindazole.6-aminoindazole or 8-aminoquinoline.The complexes have been characterised by spectral and analytical data.Pd(II) and Cu(II) form square planar complexes and Ru(III) and Ir(III) form ctahedral complexes with these Schiff bases.The DNA binding properties of theses synthesised complexes have been studied by various methods including electronic absoption spectroscopy,cyclic voltammetry,different pulse voltammetry and circular dichroism spectra were used.Gel electrophoresis experiments were also performed to investigate the DNA cleavage of theses complexes.Furthermore Ru(III) and Ir(III) complexes find application as oxidation and hydogenation catalsts. The studies on catalytic activities has been presented.The metal complexes presented in this thesis assure significance as they contribute to the development of new DNA binding agents and antibacterial and anticancer drugs.
Description:
Dept.of Applied Chemistry,Cochin University of Science and Technology
Remya, Robinson; Dr. Paulose, C S(Cochin University of Science and Technology, April , 2007)
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Abstract:
In the present study a detailed investigation on the alterations of dopamine
and its receptors in the brain regions of streptozotocin induced diabetic and insulin
induced hypoglycaemic rats were carried out. Glutamate receptor, NMDARI gene
expression in the hypoglycaemic and hyperglycaemic brain was also studied. EEG
recording in hypoglycaemic and hyperglycaemic will be carried out to measure brain
activity. in vitro studies on glucose uptake and insulin secretion, with and without
specific antagonists were carried out to confirm the specific receptor subtypes - DA
D1, DA D2 and NMDA involved in the functional regulation during hyperglycaemic
and hypoglycaemic brain damage. The molecular studies on the brain damage
through dopaminergic and glutamergic receptors will elucidate the therapeutic role in
the corrective measures of the damage to the brain during hypoglycaemia and
hyperglycaemia. This has importance in the management of diabetes and antidiabetic
treatment for better intellectual functioning of the individual.
Description:
Department of
Biotechnology, Cochin University of Science and Technology