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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.
251

The Schmidt reaction of aryl-pryidyl, alkyl-pyridyl, diaryl and alkyl-aryl ketones /

Brackenridge, David Ross January 1967 (has links)
No description available.
252

Memory ensemble selection in human information processing /

Williams, John Donald January 1970 (has links)
No description available.
253

Studies on the mechanism of uridine diphosphate-galactose-4-epimerase /

Wee, Timple Go January 1973 (has links)
No description available.
254

A study of the radiative capture reaction mechanism in ¹²C(p,γ)¹³N /

Tsin, Tsang Lin January 1976 (has links)
No description available.
255

States in 176Hf Populated by the (a,2n) Reaction

Khoo, Teng 03 1900 (has links)
The level structure of the even-even deformed nucleus 176Hf has been studied by means of the 174yb (a,2n) 176Hf reaction through y-ray singles, conversion electron and extensive prompt and delayed y-y coincidence measurements. The half-lives of the isomeric states a·t 1333 and 1559 keV have been measured as 9.5 and 9.8 usec, respectively. Besides the ground state rotational band, the following ten rotational bands have been established: two K=0+ bands at 1150 keV and 1293 keV, a K=2+ band at 1341.1 keV, a K=3+ band at 1577.3 keV, a K=2-octupole band at 1247.5 keV, two K=6+ bands of mixed neutron and proton character at 1333.1 keV and 1761.5 keV, a K=8- band at 1559.4 keV, a K=8- and/or 7- band at 1860.3 keV and a K=7-and/or 6- band at 1798.0 keV. The de-excitation of the high K states proceeds through either of the two isomers, and were studied by novel experimental techniques which involved pulsing the alpha beam. The intrinsic structure and decay properties of the states are understood in terms of the unified model. In some cases it has been necessary to make use of unpublished McMaster results from the single neutron and proton transfer reactions. / Thesis / Doctor of Philosophy (PhD)
256

The Vapour-Phase Reaction of 2-Alkyltetrahydropyrans with Aniline over Alumina

Richards, Harry 10 1900 (has links)
The vapour-phase reaction of 2-methyl-tetrahydropyran and 2-ethyltetrahydropyran with aniline over an activated alumina catalyst has been studied. The product, in each case, consisted of a mixture of an N-arylpiperidine, an N-arylpyrrolidine formed by ring contraction, and two N-alkenylanilines formed by ring opening. The structures of the nitrogen heterocyclic compounds were established by independent syntheses involving the reaction of the appropriate dibroinoalkane with aniline. The N-alkenylanilines were characterised by hydrogenation to known N-alkylanilines and by identification of the osonolysis products. / Thesis / Master of Science (MS)
257

Reaction Synthesis of HfB2 in a Variety of Metallic Environments

Dykema, Christopher Patrick 15 June 2012 (has links)
This project investigated the reactive formation of hafnium diboride (HfB2) in a variety of metallic environments, including blends with Bi, Cu, Ni, and Sb. HfB2 has garnered interest for a variety of applications due to its hardness, stability at elevated temperatures, as well as electrical and thermal conductivity. Experimental testing included differential scanning calorimetry (DSC) to reveal reaction initiation temperatures and enthalpies of reaction; and optical pyrometry to measure maximum reaction temperatures. Overall, DSC results indicated melting preceded reaction initiation; suggesting that the reaction initiation temperature for a certain blend occurred soon after melt formation, and could be broadly approximated by examination of binary phase diagrams. However, compositions containing bismuth ignited almost 200 ºC above the expected melting temperature. The maximum temperature measurement did not appear to correlate with reaction enthalpies as might be expected. This lack of correlation may be a result of an inability to capture the true maximum temperature due to the measurement frequency of the pyrometer, the disparity of heating rates between the two experimental methods, and/or to the influence of intermediate reactions on the temperature increase. / Master of Science
258

Benzyne in synthesis : a search for palladium catalysed three-component couplings

Henderson, Jaclyn January 2008 (has links)
It is over 100 years since scientists first postulated the existence of arynes as reactive intermediates. Their use in organic synthesis is now well-established and investigations into novel methods for their generation and utility in carbon-carbon bond forming reactions continue to this day. In 1983 Kobayashi and co-workers introduced a novel method of generating benzyne under mild conditions, using a fluoride induced decomposition of 2-(trimethylsilyl)phenyl triflate 1. This development has opened the door to employing arynes in a variety of transitionmetal mediated carbon-carbon bond forming processes. Intermolecular carbopalladation, in particular, stands out as a powerful methodology for the construction of diverse 1,2-functionalised arenes through multi-component coupling processes. Initial benzyne carbopalladation with an organopalladium species produces the arylpalladium intermediate 3, which can then undergo a second coupling to any one of the vast numbers of nucleophiles that have been demonstrated to work in palladium cross coupling. Presented herein are investigations towards the realisation of such methodology. Initial efforts focussed on its application to the Heck reaction, using acryates as the nucleophilic component. The chemistry has been developed to incorporate a variety of organo-halides in order to generate a variety of molecular architectures; the resultant 1,2-substituted diaryls being useful in the synthesis of both natural products and medicinal chemistry targets. Following successful development of the Heck reaction, investigations of other palladium catalysed couplings were also undertaken, in particular the Buchwald reaction. Initial mechanistic studies are also discussed.
259

Molecular Methods for Campylobacter and Arcobacter Detection

Abu-Halaweh, Marwan, n/a January 2005 (has links)
Twenty species and six subspecies of the genera Arcobacter and Campylobacter have been described to date. All are Gram-negative, microaerophilic, curved, spiral or S-shaped cells, and are members of the order Campylobacterales, class Epsilonproteobacteria phylum Proteobacteria. Though most members are pathogenic, C. jejuni, C. coli and A. butzleri are the most frequently isolated species from patients suffering from gastrointestinal illness. The current methods for their detection, identification, and differentiation are cumbersome, time consuming and lack specificity. DNA based molecular techniques including real-time Polymerase Chain Reaction (PCR) and Fingerprinting methods Terminal Restriction Fragments Length Polymorphism (T-RFLP) and Ligase Detection Reaction (LDR) have been used in this project to develop rapid detection and identification methods for Campylobacter and Arcobacter species. Five real-time PCR methods were developed which include: (a) rapid detection and identification of Campylobacter species using real-time PCR adjacent hybridisation probes, (b) rapid identification of C. jejuni using SYBR Green I, (c) rapid detection and differentiation of Arcobacter species using adjacent hybridisation probes, (d) rapid detection and differentiation of Arcobacter species and the Campylobacter group (C. coli, C. jejuni, C. lari, C. hyoilei, C. helviticus, C. hyointestinalis, C. insulaenigrae, C lanienae) using melting temperature (Tm) of adjacent hybridisation probes, and (e) a one tube real-time PCR multiplex for the rapid detection and identification of Campylobacter species, C. coli and C. jejuni using a TaqMan Probe, in an iCycler iQTM (BioRad, USA) and Light CyclerTM (Idaho Technology, USA). [Continued ...]
260

Design and Synthesis of Novel Benzimidazoles and Aminothiazoles as Small Molecule Inhibitors of CDK5/p25

Jain, Prashi 16 December 2013 (has links)
This dissertation describes the design, synthesis and biological evaluation of novel CDK5/p25 small molecule inhibitors. Cyclin dependent kinase 5 (CDK5) is a proline directed serine/threonine kinase which plays an important role in the pathology of Alzheimer's disease (AD). CDK5/p25 has been implicated in hyperphosphorylation of tau protein which forms neurofibrillary tangles (NFTs), a contributing factor to the pathology of Alzheimer's disease (AD). Based on the deposited X-ray crystal structure of CDK5/p25 with a non-selective CDK inhibitor R-Roscovitine (PDB ID: 1UNL), eight series of novel compounds with a benzimidazole core were designed, synthesized and tested as inhibitors of CDK5/p25. An efficient synthesis of trisubtituted benzimidazoles was developed to explore the SAR at the 1-, 4-, and 6- positions of the benzimidazole core. X-ray crystal structure verification of an intermediate confirmed selective alkylation of the N-1 position of the benzimidazole scaffold. Synthesis of N-1, N-4, C6-O, C6-N, C6-C and C-2 substituted benzimidazoles were achieved via Mitsunobu coupling, Suzuki Miyaura coupling, Buchwald coupling and reductive alkylation strategies. Aminothiazole scaffolds are an established class of CDK inhibitors including CDK5. A molecular hybridization technique was applied to the design of a series of 2-, 5- disubstituted aminothiazoles incorporating structural features of both the Meriolins, natural product CDK inhibitors, and known aminothiazole scaffolds. Synthetic techniques employed included aryl lithiation, deoxygenation and acylation. / Mylan School of Pharmacy and the Graduate School of Pharmaceutical Sciences / Medicinal Chemistry / PhD / Dissertation

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