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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Novel synthetic routes towards the anti-inflammatory mediator resolvin E1, and methodology development

Brown, Natalie J. January 2015 (has links)
The benefits of fish oil supplementation for inflammation based disorders has been well-documented,[1] prompting investigations into the pathways through which these benefits are achieved. This led Serhan et al. to the discovery of a new class of pro-resolution lipid mediators, termed resolvins .[2][3] There has subsequently been much research into their being a potential treatment for chronic inflammatory diseases such as asthma,[4] diabetes,[5] and arthritis.[6] The aim of this research was to study the bioactivity of resolvin E1 (RvE1) and its analogues; to do this a flexible and versatile route towards the chemical synthesis of RvE1 had to be developed, which would allow for easy modification of the stereochemistry of the C-C double bonds and hydroxyl groups, as well as producing fragments containing key functional groups. The first proposed route synthesised RvE1 from two key fragments termed the lactone and epoxide fragments. RvE1 contains three stereogenic hydroxyl groups, one with S configuration and two with R configuration. The epoxide fragment was to be converted into two adjacent sections of the RvE1 chain. The S-stereocentre was introduced via hydrolytic kinetic resolution using a Jacobsen s catalyst.[7] The two R-stereocentres were introduced via the chiral pool originating from 1,2:5,6-di-O-isopropylidene-D-mannitol. Unfortunately, problems were encountered late on in the synthesis of both fragments and therefore a new synthetic route had to be devised. The second proposed route synthesised RvE1 from two key fragments termed the alkyne and halide fragments. The S-stereocentre and one R-stereocentre were proposed to be introduced via asymmetric reduction of a ketone group. The other R-stereocentre was proposed to be synthesised with the use of chiral additives during an indium-mediated coupling reaction.[8] As work progressed on the halide fragment, the Lewis acid catalysed thermodynamic conversion of a branched chain homoallylic alcohol to its linear counterpart was trialled in order to obtain one of the conjugated diene system in RvE1. Using literature conditions for a similar system[9] this reaction was unsuccessful. The reaction mechanism was studied and a hypothesis was put forward that adding a catalytic amount of the aldehyde that the branched chain homoallylic alcohol was synthesised from to the reaction mixture would promote the thermodynamic conversion to the linear chain. These conditions were trialled on a number of different starting materials, leading to either an improvement in yield for the thermodynamic conversion, or the success of a previously unsuccessful conversion.
82

Estudos potenciométricos sobre a formção de complexos entre índio (III) e azoteto, em meio aquoso / Potentiometric studies on the formation of indium (III) azide complexes in aqueous medium

Bertotti, Mauro 16 December 1986 (has links)
O presente estudo procura dar continuidade a um dos ramos de pesquisa desenvolvidos na área de Analítica do Instituto de Química da USP, onde se procura estudar a química de complexos formados entre diferentes metais e o ânion azoteto, N-3. O cátion índio(III), à semelhança do que ocorre com o ferro (III), complexa com o ânion azoteto em meio aquoso. Este poder de complexação foi constatado em estudos polarográficos do sistema In N3+ / N-3 ora em desenvolvimento. A obtenção das constantes de estabilidade dos complexos formados entre o In3+ e o ligante azoteto, por via potenciométrica, baseia-se na alteração do pH do tampão formado por N-3 e o ácido fraco HN3, quando se adicionam íons In3+. O acompanhamento da variação da concentração hidrogeniônica foi f.eito com o auxílio do eletrodo de vidro combinado. A concentração de N-3 de equilíbrio variou de valores próximos de zero a 90 mM, para que se obtivessem dados na mais larga faixa de concentraç6es de ligante. Manteve-se a força iônica das soluções em 2,00OM (NaCI04) e trabalhou-se a 25,0οC. A análise dos dados experimentais e tratamento matemático dos mesmos, evidenciaram a formação de complexos mononucleares e os valores das constantes globais encontrados foram: β1 = (2,0 ± 0,1) x 103M-1 β2 = (7 ± 3) x 105M-2 β3 = (5 ± 1) x 107M-3 β4 = (7 ± 3) x 108M-4 / The present study is a branch of the main work concerned with the complex formation between several metal cations and azide anion in aqueous media. Indium (III) was selected, in analogy to iron (III), because forms complexes with azide in aqueous media. Polarographic studies in development showed the tendency of these complexation. To determine the stability constants of complexes was used potentiometric method using glass e1ectrode. The main advantage is based on pH modification of the buffer solution constituted by azide and hidrazoic acid (N-3;/HN3) when indium (III) cations are added in the buffer. The azide concentration was a1tered from near zero to 90 mM, the ionic strenght he1d at 2,000 M with sodium perchlorate and the temperature kept constant at 25,0°C. The evaluation of experimental data shawed mononuclear species and the global constants found were: β1 = (2,0 ± 0,1) x 103M-1 β2 = (7 ± 3) x 105M-2 β3 = (5 ± 1) x 107M-3 β4 = (7 ± 3) x 108M-4
83

Synthesis and characterization of organogallium and -indium compounds.

January 1995 (has links)
by Candy Man-Yee Chan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1995. / Includes bibliographical references. / Acknowledgements --- p.i / Abstract --- p.ii / Contents --- p.iii / Abbreviations --- p.v / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- General aspects of group 13 organometallic chemistry --- p.1 / Chapter 1.2 --- Stability of group 13 organometallic compounds --- p.3 / Chapter 1.3 --- Group 13-15 organometallic compounds -- potential single- source precursors for semiconductors --- p.5 / Chapter 1.4 --- Objective of this work --- p.7 / Chapter 1.5 --- References --- p.9 / Chapter Chapter 2 --- Synthesis and Characterization of Group 13Metal Alkyl Halide Complexes / Chapter 2.1 --- Introduction / Chapter 2.1.1 --- General synthetic methods of organogallium and indium halide complexes --- p.10 / Chapter 2.1.2 --- Structural properties of gallium and indium organometallic halides --- p.12 / Chapter 2.1.3 --- Utilization of N-functionalized sterically hindered groups as ligands --- p.14 / Chapter 2.2 --- Results and Discussions / Chapter 2.2.1 --- Synthesis of group 13 metal alkyl complexes --- p.17 / Chapter 2.2.2 --- Characterization of group 13 metal alkyl complexes --- p.23 / Chapter 2.3 --- Experimental --- p.37 / Chapter 2.4 --- References --- p.44 / Chapter Chapter 3 --- Synthesis and Characterization of Group13- 15 Organometallic Compounds / Chapter 3.1 --- Introduction / Chapter 3.1.1 --- General routes to the formation of group 13-15 covalent bond --- p.46 / Chapter 3.1.2 --- Multiple bonding between group 13 and group 15 element --- p.48 / Chapter 3.2 --- Results and Discussions / Chapter 3.2.1 --- Synthesis of group 13-15 organometallic compounds --- p.54 / Chapter 3.2.2 --- Characterization of group 13-15 organometallic compounds --- p.57 / Chapter 3.2.3 --- Discussion on multiple bond character of group13-15 organometallic compounds --- p.72 / Chapter 3.3 --- Experimental --- p.77 / Chapter 3.4 --- References --- p.81 / Appendix I --- p.83 / Appendix II --- p.88
84

Raman spectroscopy of Co2+ in MgO and of b- In2Se2

Trudel, Jacques, 1948- January 1983 (has links)
No description available.
85

Ballistic magnetotransport and spin-orbit interaction in InSb and InAs quantum wells

Peters, John Archibald. January 2006 (has links)
Thesis (Ph.D.)--Ohio University, June, 2006. / Title from PDF t.p. Includes bibliographical references (p. 119-128)
86

Structural and optical studies of indium gallium arsenide/gallium arsenide quantum dot molecules for terahertz applications

Kerr, William. January 2006 (has links)
Thesis (M.M.S.E.)--University of Delaware, 2006. / Principal faculty advisor: Valeria Stoleru, Dept. of Materials Science & Engineering. Includes bibliographical references.
87

Sub-Micron Indium Pillar Fabrications

Pervissian, Pantea 08 May 2009 (has links)
The laws of classical mechanics show that mechanical properties are independent of sample sizes. However, based on extensive theoretical work and experimentation, it is believed that reducing the size of materials to the submicron scale can result in different mechanical properties than those found in bulk quantities. This size effect was explained by the strain gradient. Atomic simulations have shown that yield stress depends on size even in the absence of the strain gradient. All of the experiments done on material creep behaviour, reported in the literature, have been conducted in the presence of strain gradient. This thesis focuses on the fabrication methods of freestanding indium pillar samples created by two unique methods; focused ion beam (FIB) and the micro-fabrication approach. The low melting point indium metal limits the application of FIB to form the sub-micron pillars. As a result, two different micro-lithography techniques, ultra-violet radiation and electron-beam lithography, were developed to fabricate these nano-pillars. In order to monitor the creep mechanism, which was dominant in this testing, the samples were then divided into two groups: polycrystalline and single-crystal pillars, each in different sizes. These pillars will later be compressed by a nano-indenter using a flat punch. Compressive stress, strain, and stiffness of the pillars will be measured to verify if the indium mechanical behavior deviates from the bulk in the absence of strong strain gradient.
88

Sub-Micron Indium Pillar Fabrications

Pervissian, Pantea 08 May 2009 (has links)
The laws of classical mechanics show that mechanical properties are independent of sample sizes. However, based on extensive theoretical work and experimentation, it is believed that reducing the size of materials to the submicron scale can result in different mechanical properties than those found in bulk quantities. This size effect was explained by the strain gradient. Atomic simulations have shown that yield stress depends on size even in the absence of the strain gradient. All of the experiments done on material creep behaviour, reported in the literature, have been conducted in the presence of strain gradient. This thesis focuses on the fabrication methods of freestanding indium pillar samples created by two unique methods; focused ion beam (FIB) and the micro-fabrication approach. The low melting point indium metal limits the application of FIB to form the sub-micron pillars. As a result, two different micro-lithography techniques, ultra-violet radiation and electron-beam lithography, were developed to fabricate these nano-pillars. In order to monitor the creep mechanism, which was dominant in this testing, the samples were then divided into two groups: polycrystalline and single-crystal pillars, each in different sizes. These pillars will later be compressed by a nano-indenter using a flat punch. Compressive stress, strain, and stiffness of the pillars will be measured to verify if the indium mechanical behavior deviates from the bulk in the absence of strong strain gradient.
89

High electric field current transport in semi-insulating GaAs and InP

Luo, Yilin. January 2000 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 230-253).
90

Theoretical and experimental studies of electronic states in InAs/GaAs self-assembled quantum dots

Wen, Yuan, January 2009 (has links)
Thesis (M. Phil.)--University of Hong Kong, 2010. / Includes bibliographical references (leave 60). Also available in print.

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