Ueber 2, 4, 5 trimethyldibenzylamin und 2, 4, 5 trimethyldibenz...

Thesis (doctoral)--

Uber das (1)-tolyl-(3)-phenyl-(4, 5)-pyrazolindion.

Thesis (doctoral)--

Fair Employment Practice Act (Chapter 121, Part 4.5, Division 2, Labor code) : FEPC rules and regulations : guide to pre-employment inquiries.

Cover title.

Livret officiel de la Fête des vignerons se célébrant à Vevey les 4,5,7,8,10 et 11 août 1905.

Mode of access: Internet.

A stable rearrangement product of humulene-4,5-epoxide

Humulene-4,5-monoepoxide, 1, may rearrange to the cyclopropyl diol 2 during chromatography over silica. The rearrangement can be reversed with acid.

Flexible synthesis of enantiomerically pure 2,8-dialkyl-1,7-dioxaspiro[5.5]undecanes and 2,7-dialkyl-1,6-dioxaspiro[4.5]decanes from propargylic and homopropargylic alcohols

A new approach to enantiomerically pure 2,8-dialkyl-1,7-dioxaspiro[5.5]undecanes and 2,7-dialkyl-1,6-dioxaspiro [4.5] decanes is described and utilizes enantiomerically pure homopropargylic alcohols obtained from lithium acetylide opening of enantiomerically pure epoxides, which are, in turn, acquired by hydrolytic kinetic resolution of the corresponding racemic epoxides. Alkyne carboxylation and conversion to the Weinreb amide may be followed by triple-bond manipulation prior to reaction with a second alkynyllithium derived from a homo- or propargylic alcohol. In this way, the two ring components of the spiroacetal are individually constructed, with deprotection and cyclization affording the spiroacetal. The procedure is illustrated by acquisition of (2S,5R,7S) and (2R,5R,7S)-2-n-butyl-7-methyl-1,6-dioxaspiro[4.5]-decanes (1), (2S,6R,8S)-2-methyl-8-n-pentyl-1,7-dioxaspiro[5.5]undecane (2), and (2S,6R,8S)-2-methyl-8-n-propyl-1,7-dioxaspiro[5.5]undecane (3). The widely distributed insect component, (2S,6R,8S)-2,8-dimethyl-1,7-dioxaspiro[5.5]undecane (4), was acquired by linking two identical alkyne precursors via ethyl formate. In addition, [H-2(4)]-regioisomers, 10,10,11,11-[H-2(4)] and 4,4,5,5-[H-2(4)] of 3 and 4,4,5,5-[H-2(4)]-4, were acquired by triple-bond deuteration, using deuterium gas and Wilkinson's catalyst. This alkyne-based approach is, in principle, applicable to more complex spiroacetal systems not only by use of more elaborate alkynes but also by triple-bond functionalization during the general sequence.

A dual band 2.4/5.2GHz antenna including a radial line slot array and a patch

The design of an antenna that combines a radial line slot array and a circular patch to operate as a dual band (2.4/5.2 GHz) antenna at the access point of a WLAN is presented. The design has been accomplished using commercially available Ansoft HFSS and in-house developed software. The designed antenna shows good performance in terms of return losses, radiation pattern and circular polarization in the two, 2.4 and 5.2 GHz, frequency bands. Due to its good electrical performance and a relatively low profile and low developmental cost, it should be found attractive for use as an access point antenna for dual band operation.

Investigations into a dual band 2.4/5.2GHz antenna for WLAN applications

The design of a dual-band 2.45/5.2 GHz antenna for an access point of a wireless local area network (WLAN) is presented. The proposed antenna is formed by an assembly of a radial line slot array (RLSA) operating at 2.4 GHz and a microstrip patch working at 5.2 GHz. The design of this antenna system is accomplished using commercially available finite element software, high frequency structure simulator (HFSS), of Ansoft. The performance of the designed antenna is assessed in terms of return loss (RL), radiation pattern and polarization purity in the two investigated frequency bands.

A combinatorial approach to the chemical synthesis and biological evaluation of 3,4,5-trisubstiituted furan-2(5H)-ones

Many important natural products contain the furan-2(5H)-one structure. The structure of this molecule lends itself to manipulation using combinatorial techniques due to the presence of more than one site for the attachment of different suhstituents. By developing different reaction schemes at the three sites available for attachment on the furan-2(5H)-one scaffold, combinatorial chemistry techniques can be employed to assemble libraries of novel furan 2(5H)-ones. These libraries can then be entered into various biological screening programmes. This approach will enable a vast diversity or compounds to be examined, in the hope or finding new biologically active Iead structures. The work in this thesis has investigated the potential that combinatorial chemistry has in the quest for new biologically active lead structures based on the furan-2(5H)-one structure. Different reactions were investigated with respect to their suitability for inclusion in a library. Once sets of reactions at the various sites had been established, the viability of these reactions in the assembly of combinatorial libraries was investigated. Purification methods were developed, and the purified products entered into suitable biological screening tests. Results from some of these tests were optimised using structure activity relationships, and the resulting products re-screened. The screening tests performed were for anticancer and antimicrobial activity, cholecystokinin (CCK-B) antagonism and anti-inflammatory activity (in the quest for novel cyclo-oxygenase (COX-2) selective non-steroidal anti-inflammatory drugs). It has been shown that many reactions undergone by the furan-2(5H)-one structure are suitable for the assembly of a combinatorial library. Investigation into the assembly of different libraries has been carried out with initial screening results included. From this work, further investigation into combinatorial library assembly and structure activity relationships of screened reaction products can be undertaken.

Exploration of steroselective cleavage of 4, 5-epoycholestane-3, 6-diols and stero controlled epoxidation of cholest-4-en-3 β, 6β-diol-6-acetate

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An Ins(1,4,5)P3 receptor in Paramecium is associated with the osmoregulatory system

In the ciliate Paramecium, a variety of well characterized processes are regulated by Ca2+, e.g. exocytosis, endocytosis and ciliary beat. Therefore, among protozoa, Paramecium is considered a model organism for Ca2+ signaling, although the molecular identity of the channels responsible for the Ca2+ signals remains largely unknown. We have cloned - for the first time in a protozoan - the full sequence of the gene encoding a putative inositol (1,4,5)-trisphosphate (Ins(1,4,5)P3) receptor from Paramecium tetraurelia cells showing molecular characteristics of higher eukaryotic cells. The homologously expressed Ins(1,4,5)P3-binding domain binds [3H]Ins(1,4,5)P3, whereas antibodies unexpectedly localize this protein to the osmoregulatory system. The level of Ins(1,4,5)P3-receptor expression was reduced, as shown on a transcriptional level and by immuno-staining, by decreasing the concentration of extracellular Ca2+ (Paramecium cells rapidly adjust their Ca2+ level to that in the outside medium). Fluorochromes reveal spontaneous fluctuations in cytosolic Ca2+ levels along the osmoregulatory system and these signals change upon activation of caged Ins(1,4,5)P3. Considering the ongoing expulsion of substantial amounts of Ca2+ by the osmoregulatory system, we propose here that Ins(1,4,5)P3 receptors serve a new function, i.e. a latent, graded reflux of Ca2+ to fine-tune [Ca2+] homeostasis.