927 resultados para Health Sciences, Occupational Health and Safety|Health Sciences, Public Health|Sociology, Ethnic and Racial Studies


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Polymer supports and polymeric complexes are highly versatile and they are successfully employed as efficient reagents, substrates and catalysts. Recently there observed a growing interest in the synthesis of tailor-made polymer supports and functionalized polymers for the preparation of metal complexes for various applications. They have the combination of properties due to the macromolecular structure as well as due to the reactivity of the functional group. An interesting feature of functional polymers is their affinity towards metal ions. Therefore the synthesis, characterization and application of such polymeric complexes have great scientific and analytical importance. In this investigation three series of polymeric complexes of transition metal ions are prepared from three schiff bases. All the complexes and polymeric schiff bases were characterized by analytical, spectral and thermal methods The thesis consist of six chapters. The first chapter contains an introduction and a brief review on application of polymer supports, polymer supported ligands and complexes. The second chapter gives the details of reagents and instruments used and the procedure adopted for the preparation of ligands and complexes. The third chapter explains the methods employed for characterization and the results are also discussed. The fourth chapter gives a detailed study of metal ion removal using ligands whereas the fifth chapter describes the development of the Cu” ion sensor electrode. The sixth chapter is the summary of the thesis and references are presented at the end.

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The thesis is mainly concerned with the study of the bacteriology of freezing of mackerel(Rastrelliger kanaggrta)and prawn (Metgpggaeus ddbsoni) The thesis in four sections describes the salient features of the observations and inferences on the bacteriology of freezing of fishes and prawns. This includes the evaluation of methodology for the optimum recovery of bacteria, bacteriology of the newly caught fish and prawn, the effect of freezing temperatures on the survival of selected species of isolates from fish and prawn and the bacteriology of freezing, frozen storage and thawing of prawn/fish emphasizing the effect contributed by each.

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Semicarbazones and their transition metal complexes have been receiving considerable attention because of their biological relevance and applications in the field of analysis and in the field of organic NLO materials. Their structural diversity also attracted inorganic chemists. A good deal of work has been reported on the synthesis and structural investigation of semicarbazones and their complexes. This is due partially to their capability of acting as multidentate, NO, NNO, ONO and ONNO donors with the formation of either mono or bi or polynuclear complexes. Their chemistry and pharmacological applications have been extensively investigated. Appreciable biological applications as well as diverse stereochemistry of their metal complexes prompted us to synthesize two new tridentate ONO donor N4-phenyl semicarbazones derived from 2-hydroxy-4-methoxyacetophenone and 2-hydroxy-4-methoxybenzophenone and their transition metal complexes. These ketones were selected since they can provide a further binding site from phenolic–OH and can thus increase the denticity. Introduction of heterocyclic bases like 1,10-phenanthroline, 2,2′-bipyridine, 4,4′-dimethyl- 2,2′-bipyridine and 4-picoline and some pseudohalides like azide and thiocyanate ion can result in mixed ligand metal chelates with different geometries in coordination compounds In the present study, oxovanadium(IV), manganese(II), cobalt (II/III), nickel(II), copper(II) and zinc(II) complexes of 2-hydroxy-4- methoxyacetophenone-N4-phenylsemicarbazone (H2ASC) and 2-hydroxy-4- methoxybenzophenone-N4-phenylsemicarbazone (H2BSC) were synthesized and characterized.

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Laser engineering is an area in which developments in the existing design concepts and technology appear at an alarming rate. Now—a-days, emphasis has shifted from innovation to cost reduction and system improvement. To a major extent, these studies are aimed at attaining larger power densities, higher system efficiency and identification of new lasing media and new lasing wavelengths. Todate researchers have put to use all the ditferent Forms of matter as lasing material. Laser action was observed For the first time in a gaseous system - the He-Ne system. This was Followed by a variety of solidstate and gas laser systems. Uarious organic dyes dissolved in suitable solvents were found to lase when pumped optically. Broad band emission characteristics of these dye molecules made wavelength tuning possible using optical devices. Laser action was also observed in certain p-n junctions of semiconductor materials and some of these systems are also tunable. The recent addition to this list was the observation of laser action from certain laser produced plasmas. The purpose of this investigation was to examine the design and Fabrication techniques of pulsed Nitrogen lasers and high power Nd: Glass laserso Attempt was also made to put the systems developed into certain related experiments

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Cochin, commercial capital of Kerala, located on the west-coast of South India has a large number of chemical and sea food industries. Earlier studies in the past indicated that these industries contribute to heavy metal pollution, particularly mercury, copper, and cadmium, in Cochin backwater. Hence, in the present study, it was desired to isolate cadmium resistant bacteria from effluent discharged by chemical industry with a view to develop an ideal bioremediation process for safe discharge of industrial effluent in to the nearby aquatic environment. Effluent from three industries, located in the industrial belt of Cochin, were collected from the discharge point and cadmium resistant bacteria were screened using standard microbiological techniques

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In the present thesis a series of exhaustive investigations have been carried out on a number of crystalline samples with special reference tx> the jphase transitions exhibited by them. These include single crystals of pure, doped or deuterated specimens of certain ammonium containing crystals viz., (NH )34H(SO4)2, (NH4)2HPO4, (NH4)2Cr2O7 znui NH4H2PO4. ac/dc electrical conductivity, dielectric constant, ionic thermocurrent as wwifil as photoacoustic measurements have been carried out on most of them over a wide range of temperature. In addition investigations have been carried out in pure and doped single crystals of NaClO3 and NaNO3 using ionic thermocurrent measurements and these are presented here. Special attention has been paid to reveal the mechanism of electrical conduction in various phases of "these crystals and to evaluate the different parameters involved in the conduction as well as phase transition process. The thesis contains ten chapters ‘

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Fishes are one of the most important members of the aquatic food chain, and through them some toxicants may reach human beings as well. The selection of organisms for toxicity test is mainly based on certain criteria like its ecological status, position within the food chain, suitability for laboratory studies, genetically stable, uniform populations and adequate background data on the organism (Buikema et al., 1982). The species selected for the present study Etroplus maculatus satisfy most of the above protocols. Rechten (1980) opined it as a laboratory favorite of fish researchers. However, there are difficulties in the rise of fishes for pollution assessment impact. Most important of these is our limited understanding of the mechanism of toxicity. The interpretation of the significance or specificity of a measured biological response could there for become difficult. Not withstanding these limitations, attempts have been made to the normal haematology and to analyze the impact of heavy metal at realistic levels to the experimental media, on the haematology, and enzymatic activity and histology of Etroplus maculatus

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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.

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The work embodied in the thesis is divided into eight chapters. Chapter I gives a brief introduction about metal complexes of thiosemicarbazones, including their structural and bonding properties. Chapter 2 deals with the synthesis and single crystal X-ray diffraction studies of various thiosemicarbazones used up for the present investigations and various characterization techniques. Chapter 3 deals with synthesis, spectral and structural studies of Cu(U) complexes with ONS donor thiosemicarbazones. Chapter 4 deals with synthesis and spectral studies of Ni(II) complexes \vith 2-hydroxyacetophenone N(4)-cyclohexyl thiosemicarbazone as the ligand. Chapter 5 includes synthesis and spectral studies of Mn(II) complexes. Chapter 6 deals with synthesis, spectral and structural studies of Zn(II) complexes. Chapter 7 includes synthesis and spectral studies of oxovanadium(IV) complexes. Chapter 8 deals with synthesis, spectral and single crystal X-ray diffraction studies of dioxomolybdenum(VI) complexes.

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Aqua complex ions of metals must have existed since the appearance of water on the earth, and the subsequent appearance of life depended on, and may even have resulted from the interaction of metal ions with organic molecules. Studies on the coordinating ability of metal ions with other molecules and anions culminated in the theories of/\lfred Werner. Thereon the progress in the studies of metal complex chemistry was rapid. Many factors, like the utility and economic importance of metal chemistry, the intrinsic interest _in many of the compounds and the intellectual challenge of the structural problems to be solved, have contributed to this rapid progress. X—ray diffraction studies further accelerated the progress. The work cited in this thesis was carried out by the author in the Department of Applied Chemistry during 2001-2004. The primary aim of these investigations was to synthesise and characterize some transition metal complexes of 2-benzoylpyridine N(4)-substituted thiosemicarbazones and to study the antimicrobial activities of the ligands and their metal complexes. The work is divided into eight chapters

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A new semicarbazone, HL has been synthesized from quinoline-2-carboxaldehyde and N4-phenyl-3- semicarbazide and structurally and spectrochemically characterized. 1H NMR, 13C NMR, IR and electronic spectra of the compound are studied. The existence of keto form in the solid state is supported by the crystal structure and IR data. The compound crystallizes into an orthorhombic space group P212121. Intra and intermolecular hydrogen bonding interactions facilitates unit cell packing in the crystal lattice

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Five copper(II) complexes [CuLCl]2·CuCl2·4H2O (1), [CuLOAc] (2), [CuLNO3]2 (3), [CuLN3] (4) and [CuLNCS]·3/2H2O (5) of di-2-pyridyl ketone-N4-phenyl-3-semicarbazone (HL) were synthesized and characterized by elemental analyses and electronic, infrared and EPR spectral techniques. In all these complexes the semicarbazone undergoes deprotonation and coordinates through enolate oxygen, azomethine and pyridyl nitrogen atoms. All the complexes are EPR active due to the presence of an unpaired electron. EPR spectra of all the complexes in DMF at 77K suggest axial symmetry and the presence of half field signals for the complexes 1 and 3 indicates dimeric structures

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Oxovanadium(IV/V) complexes of 2-hydroxyacetophenone- 3-hydroxy-2-naphthoylhydrazone (H2L) have been synthesized and characterized. The complexes were characterized by elemental analyses, IR, electronic and EPR spectra. The oxovanadium(V) complex [VOL (OCH3)] is crystallized in two polymorphic forms, denoted by 1a and 1b, with space groups Pn21a and P 1, respectively. Both have distorted square pyramidal structures.

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A novel binuclear Ni(II) complex of salicylaldehyde 3-azacyclothiosemicarbazone (H2L) has been synthesized and characterized by elemental analysis, IR and UV–Vis spectroscopy. The single crystal X-ray structure of the complex shows that bridging occurs through thiolato sulfur and phenolic oxygen atoms. Nickel centers in the complex have square planar and octahedral geometries

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A new class of chiral polyurethanes containing amido linkages in the polymer backbone have been synthesized by reacting toluene diisocyanate with isosorbide (IS) chiral moiety and the chromophores [N,N0-ethane- 1,2-diyl bis(6-hydroxy hexanamide), N,N0-butane-1,4-diyl bis(6-hydroxy hexanamide) and N,N0-hexane-1,6-diyl bis (6-hydroxy hexanamide)]. The corresponding chromophores were obtained by the aminolysis of e-caprolactone by using the diamines, diaminoethane, diaminobutane and diaminohexane, respectively. All the polymers were synthesized according to the symmetry conditions so as to obtain the non-centrosymmetric environment. A series of polyurethanes were synthesized by varying the chiral– chromophore composition. The polyurethanes developed were characterized by optical and thermal methods.