Physicochemical and Biochemical Characterization of Enzymes Immobilized on lnorganic Matrices

Biotechnology is currently considered as a useful altemative to conventional process technology in industrial and catalytic fields. The increasing awareness of the need to create green and sustainable production processes in all fields of chemistry has stimulated materials scientists to search for innovative catalysts supports. lmmobilization of enzymes in inorganic matrices is very useful in practical applications due to the preserved stability and catalytic activity of the immobilized enzymes under extreme conditions. Nanostructured inorganic, organic or hybrid organic-inorganic nanocomposites present paramount advantages to facilitate integration and miniaturization of the devices (nanotechnologies), thus affording a direct connection between the inorganic, organic and biological worlds. These properties, combined with good chemical stability, make them competent candidates for designed biocatalysts, protein-separation devices, drug delivery systems, and biosensors Aluininosilicate clays and layered double hydroxides, displaying, respectively, cation and anion exchange properties, were found to be attractive materials for immobilization because of their hydrophilic, swelling and porosity properties, as well as their mechanical and thermal stability.The aim of this study is the replacement of inorganic catalysts by immobilized lipases to obtain purer and healthier products.Mesocellular silica foams were synthesized by oil-in-water microemulsion templating route and were functionalized with silane and glutaraldehyde. " The experimental results from IR spectroscopy and elemental analysis demonstrated the presence of immobilized lipase and also functionalisation with silane and glutaraldehyde on the supports.The present work is a comprehensive study on enzymatic synthesis of butyl isobutyrate through esterification reaction using lipase immobilized onto mesocellular siliceous foams and montmorillonite K-10 via adsorption and covalent binding. Moreover, the irnrnobil-ization does not modify the nature of the kinetic mechanism proposed which is of the Bi-Bi Ping—Pong type with inhibition by n-butanol. The immobilized biocatalyst can be commercially exploited for the synthesis of other short chain flavor esters. Mesocellular silica foams (MCF) were synthesized by microemusion templating method via two different routes (hydrothermal and room temperature). and were functionalized with silane and glutaraldehyde. Candida rugosa lipase was adsorbed onto MCF silica and clay using heptane as the coupling medium for reactions in non-aqueous media. I From XRD results, a slight broadening and lowering of d spacing values after immobilization and modification was observed in the case of MCF 160 and MCF35 but there was no change in the d-spacing in the case of K-10 which showed that the enzymes are adsorbed only on the external surface. This was further confirmed from the nitrogen adsorption measurements

Combined toxic effects of oil and pesticides on selected marine invertebrates

In recent years, pollution in general and sea water pollution in particular, has become an important topic for national and international considerations. Because of its impact on society, marine pollution has attracted great attention from politicians, administrators, natural scientists and technologists all over the world. To save our environment from further deterioration, it is essential to have an assessment of this problem This thesis involves investigation of the lethal and sub lethal effects of four pesticides and two petroleum oil, individually and in combinations on two commercially important bivalves. Among the four pesticides used two are organophosphates and the other two are organochlorines. Synthetic Pesticides, especially organophosphates and organochlorines have become increasingly important additions to chemical wastes polluting natural aquatic Communities special attention is given in the present investigation to delineate the combined toxic effect of oil and pesticides. The results are presented under different sections to make the presentation meaningful.

Studies on the Hydrobiology and pollution of the Vembanad Lake and adjacent waters

The Thesis deals with the entire estuarine system in totality on several parameters related to hydrography, ecology of biota, productivity and also the effects of pollution. The objective of this study has been to review the systems physical, chemical and biological features through varying periods of time at locations where human interference is high so that an overall assessment of the changing ecology could be made so as to impress on the scientific community whether remedial measures could be undertaken in sensitive areas. It is also the objective of this study to point out thrust areas where concerted efforts from a larger body of scientists and administrators who can sit together and chalk out programmes for a co-operative endeavor in monitoring the most sensitive areas and also suggest ways and means to exploit the rich and diverse resources at optimum levels with emphasis on conservation and protection from environmental degradation resulting in depletion of resources. Areas also have been identified which are potentially more productive where aquaculture could be intensified

Investigations on the Radiation Characteristics of Broadband Strip Loaded Slotted Microstrip Antennas

With the recent progress and rapid increase in mobile terminals, the design of antennas for small mobile terminals is acquiring great importance. In view of this situation, several design concepts are already been addressed by the scientists and engineers. Compactness and efficiency are the major criteria for mobile terminal antennas. The challenging task of the microwave scientists and engineers is to device compact printed radiating systems having broadband behavior, together with good efficiency. Printed antenna technology has received popularity among antenna scientists after the introduction of microstrip antenna in 1970s. The successors in this kind such as printed monopoles and planar inverted F are also equally important. Scientists and Engineers are trying to explore this technology as a viable coast effective solution for forthcoming microwave revolution. The transmission line perspectives of antennas are very interesting. The concept behind any electromagnetic radiator is simple. Any electromagnetic system with a discontinuity is radiating electromagnetic energy. The size, shape and the orientation of the discontinuities controls the radiation characteristics of the system such as radiation pattern, gain, polarization etc. It can be either resonant or non resonant structure. Microstrip antennas are suitable for wireless applications due to their low cost, high gain and ease of fabrication. But the major disadvantage of micro strip antennas is their inherent narrow bandwidth. A lot of techniques are introduced by the researchers all over the world to enhance the bandwidth of micro strip patch antennas. The thesis addresses an attempt to enhance the bandwidth of micro strip patch antennas by incorporating impedance matching strip as a part of the micro strip patch antenna. The first part of the thesis deals with the broadband operation of the tilted square slot and polygonal slot loaded square micro strip patch antennas. The resonant mechanisms are clearly mentioned using the simulation and experimental studies. The bandwidth of the polygonal slotted broadband patch antenna is again enhanced by implementing an Lstrip feed mechanism. In the second major part of the thesis, a novel gain enhancement technique for single band and broadband square micro strip patch antennas is achieved by implementing offset stacked configurations.

Studies on electroluminescence using Powder and thin film devices

The subject of electroluminescence has currently acquired great importance because of its potential applications in display systems of a wide variety. A large number of scientists working in commercial, governmental as well as academic institutions all over the world are at present engaged in the intense effort to develop new and efficient phosphor materials and electroluminescent devices. This thesis presents the work carried out by the author in this field during the past few years. The studies discussed in this thesis are mostly confined to the development of some new phosphor materials, their uses in powder and thin film electroluminescent devices and to their electrical and spectral characteristics. Care has been taken to bring' out the physics involved in all the above aspects of the phenomenon

ARMA modeling of time series based on rational approximation of spectral density function

This study is concerned with Autoregressive Moving Average (ARMA) models of time series. ARMA models form a subclass of the class of general linear models which represents stationary time series, a phenomenon encountered most often in practice by engineers, scientists and economists. It is always desirable to employ models which use parameters parsimoniously. Parsimony will be achieved by ARMA models because it has only finite number of parameters. Even though the discussion is primarily concerned with stationary time series, later we will take up the case of homogeneous non stationary time series which can be transformed to stationary time series. Time series models, obtained with the help of the present and past data is used for forecasting future values. Physical science as well as social science take benefits of forecasting models. The role of forecasting cuts across all fields of management-—finance, marketing, production, business economics, as also in signal process, communication engineering, chemical processes, electronics etc. This high applicability of time series is the motivation to this study.

Studies on some nonlinear optical phenomena-optical phase conjugation and continuous wave second harmonic generation

Nonlinear optics has emerged as a new area of physics , following the development of various types of lasers. A number of advancements , both theoretical and experimental . have been made in the past two decades . by scientists al1 over the world. However , onl y few scientists have attempted to study the experimental aspects of nonlinear optical phenomena i n I ndian laboratories. This thesis is the report of an attempt made in this direction. The thesis contains the details of the several investigations which the author has carried out in the past few years, on optical phase conjugation (OPC) and continuous wave CCVD second harmonic generation CSHG). OPC is a new branch of nonlinear optics, developed only in the past decade. The author has done a few experiments on low power OPC in dye molecules held in solid matrices, by making use of a degenerate four wave mixing CDFWND scheme. These samples have been characterised by studies on their absorption-spectra. fluorescence spectra. triplet lifetimes and saturation intensities. Phase conjugation efficiencies with r espect to the various parameters have been i nvesti gated . DFWM scheme was also employed i n achievi ng phase conjugation of a br oadband laser C Nd: G1ass 3 using a dye solution as the nonlinear medium.

Organisational alienation: A study with special reference to Kerala water authority

The term 'organisation' is used in different contexts. In this study, organisation is considered as a 'socio—technical system. Alienation, as a term and as a theme, are found in many writings from very early times. But the concept and emphasis differ. The writers who have explained alienation includes theologians, philosophers, anthropologists, economists, political scientists, historians, psychologists and sociologists

Bionomics, Resource Characteristics And Distribution Of The Threatened Freshwater Fishes Of Kerala

The previous faunistic studies were concentrated.on the taxonomical and zoogeo— graphical aspects. These studies contributed to many new additions to the fish fauna of Kerala meanwhile many species described earlier are reported missing in recent years. Many fish species were collected only once or twice by scientists. Detailed information on distribution, habitat, feeding habits, reproduction, population size, etc. are available only with regard to a very few fish species. A meaningful assessment on the biodiversity status of the majority of freshwater fishes cannot be done for want of sufficient data base and therefore, no suitable conservation and management programmes are forthcoming for the protection and preservation of the unique fish germplasm resources of Kerala. The present study was conceptualised and undertaken mostly aiming at bridging these gaps by generating an authentic data base on the distribution, resource characteristics and bionomics of the threatened fishes inhabiting the rivers of Kerala. Osteobrama bakeri (Day) is an endemic fish having a very highly restricted and fragmented distribution in Periyar, Chalakudy, Kabini, Kallada and Meenachil rivers of Kerala. This belongs to vulnerable category and is locally known as Mullanpaval which is valued as food fish. Besides, due to its vibrant and attractive colouration and easiness for domestication, it has great potential for being propagated as an ornamental fish. Hitherto, no information is available on the bionomics and resource characteristics of this species. Studies on detailed life history traits are indispensable for fishery management, development of captive breeding technique and implementation of various conservation programmes. In the present study, a pioneer attempt is also made to investigate the life history traits, resource characteristics, proximate composition, etc. of O.baken'.

Fabrication And Parametric Measurements Of N2 Laser Pumped Dye Laser And Its Application To Energy Transfer Studies In Mixed Dyes

Eventhough a large number of schemes have been proposed and develoned for N9 laser ouined dye lasers the relatively low efficiency compelled the scientists to device new methods to improve the system efficiencs. Energy transfer mechanism has been shown to he a convenien tool for the enhancement of efficiency of dye lasers. Th p resent work covers a detailed study of the performance characteristics of a N2 laser pumped dye laser in the con— ventional mode and also, when pumped by the energy transfer mechanism. For .th.e present investigations a dye laser pumped by a'N2 laser (A4200 kw peak power) was fabricated. The grating at grazing incidence was used as the beam expanding device; A t its best performance the system was giving an output peak power of l5 kW for a 5 X lC"3H/l Rh—€ solution in methanol. T he conversion efficiency was 7.5; The output beam was having 3 divergence of 2 mrad and bandwidth o.9 A. Suitable modifications were suggested for obtaining better conversion efficiency and bandwidth.

”Studies on Selected conducting polymers for Microwave and Electrical Applications

The electrical properties of polymers make up an inherently interdisciplinary topic, being closely associated, on the one hand, with the mechanical properties of polymers polarization and relaxation) and, on the other hand, with the semi conductive properties (conduction and break down). In addition, unlike conventional technologies, which use these properties in its various applications like antistatic coatings, rechargeable batteries, sensors, electrochromic devices, electrochemical devices etc, microwave technology extract the microwave absorbing ability of electrically conducting polymers. The conducting polymers are widely used in its potential applications like electro magnetic interference shielding, satellite communication links, beam steering radars, frequency selective surfaces etc. Considering the relevance of microwave applications of conducting polymers, the study of microwave properties of conducting polymers stands poised to become a compelling choice for synthetic chemists and condensed - matter physicists, physical chemists and material scientists, electrochemists and polymer scientists. The main aim of the present work is to study the microwave and low frequency properties of various conducting polymers, conducting semi-interpenetrating networks, conducting copolymers and to characterise it. Also this thesis collated the microwave properties of these conducting systems and exposes the various technologically important applications in the industrial, scientific, communication and defence applications.

Fermentation Of Rice And Related Products By Bacillus Sp.

Recently’ recognition cnf immobilization ‘technology for the rapid conversion of several substrates into metabolites and repeated reuse of the biocatalysts have drawn the attention of the fermentation scientists and technologists to try these new technologies for the rapid production of pnxkmt and enhancement of the efficiencies of the systems Hence in the present study rice was selected,as a substrate since it is a rich source of starch, available and cultivated throughout the year almost in all part of our country. Rice although known for its use as a staple food in many forms as rice, idli, dosai etc., has not been used in industry extensively. However, it ii; a potential resource for’ the production of alcohol, high protein food anui for sugar and sugar syrups as it is evidenced by the few reports mentioned in the review of literature. Of the several microorganisms available, Bacillus sp, is a known candidate for the production of amylases. Hence in the present study Bacillus sp, was desired for its known efficiencies in starch conversion

Studies on some aspects of mangrove ecosystem in a tropical estuary"

The situation in the backwaters of Kerala, which reportedly had about 70,000 ha of mangroves, is unique in the sense that there has been a total conversion to other uses such as paddy cultivation, coconut plantation, aquaculture, harbour development and urban development In order to save and restore what is left over national and international organisations are mounting pressure on scientists and policy makers to work out ways and means conserving and managing the mangrove ecosystems. In this context, it has been observed in recent years that mangrove vegetation has remained intact in isolated pockets of undisturbed areas in the Cochin estuarine system and also that there is resurgence of mangroves in areas of accretion and silting. The candidate took up the present study with a view to make an inventory of the existing mangrove locations, the areas of resurgence, species composition, zonation and other ecological parameters to understand their dynamism and to suggest a mangement plan for this important coastal ecosystem

“Seaweed exudates and settlement behaviour of sedentary organisms"

The present investigation has looked exclusively into the aspect of the biological phenomenon of settling behaviour by two serious fouling offenders encountered in the tropical seas mainly on the hulls of ships and stationary structures in the harbours. The cue to study the behaviour was adopted from the observations so far made by scientists on the epizoic growth of these organisms on the surfaces of algal fronds of variegated shape, texture, size etc. The results do indicate that there are sufficient qualities of bioactive substances produced by plants occupying the lowest categories in organic evolution and curiously enough these substances have withstood the test of time.

On the Tailoring of Magnetic Properties of Fe-Based Alloy Thin Films by Swift Heavy Ion Irradiation and Thermal Annealing

The development of new materials has been the hall mark of human civilization. The quest for making new devices and new materials has prompted humanity to pursue new methods and techniques that eventually has given birth to modern science and technology. With the advent of nanoscience and nanotechnology, scientists are trying hard to tailor materials by varying their size and shape rather than playing with the composition of the material. This, along with the discovery of new and sophisticated imaging tools, has led to the discovery of several new classes of materials like (3D) Graphite, (2D) graphene, (1D) carbon nanotubes, (0D) fullerenes etc. Magnetic materials are in the forefront of applications and have beencontributing their share to remove obsolescence and bring in new devices based on magnetism and magnetic materials. They find applications in various devices such as electromagnets, read heads, sensors, antennas, lubricants etc. Ferromagnetic as well as ferrimagnetic materials have been in use in the form of various devices. Among the ferromagnetic materials iron, cobalt and nickel occupy an important position while various ferrites finds applications in devices ranging from magnetic cores to sensors.