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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.
21

Total synthesis of the marine sesquiterpenes (±) dactylol and (±)-africanol : a synthetic approach toward (±)-neolemnanyl acetate /

Ham, Won-hun January 1986 (has links)
No description available.
22

The effects of acetate and malonate on growth and fatty acid biosynthesis in Aspergillus niger

Peterson, David L. January 1972 (has links)
The purpose of this research was to determine the effects of adding alternate carbon sources to a ten percent glucose or sucrose medium on growth, fatty acid distribution, and incorporation of radioactive carbon sources into lipids using submerged Aspergillus niger cultures.
23

Thermal gas phase rearrangements of trans-[alpha], [gamma]-dimethylallyl acetate and exo-2-bicyclo-[3.2.1.]oct-3-enyl acetate II. Synthesis and resolution of cis-[alpha], [gamma]-dimethylallyl alcohol : III. Determination of absolute configuration of (+)-cis-[alpha], [gamma]-dimethylallyl alcohol.

Cosper, David. January 1969 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1969. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
24

Measurements of plasma acetate concentrations in humans, with reference to diabetes, dietary composition and bowel function

Akanji, Abayomi Olusola January 1987 (has links)
This thesis examined aspects of production and utilization of acetate in humans via measurements of plasma concentrations in different circumstances with particular attention to changes in diabetes. Circulating plasma acetate was measured by a modified acetate kinase-based enzymatic spectrophotometric method with adequate sensitivity and specificity for levels encountered in human plasma. Fasting plasma acetate was increased in diabetics and correlated with glucose and indices of glucose disposal. Levels increased further when they were fed different high- fibre diets. The rise in acetate levels after lactulose ingestion correlated with changing breath hydrogen excretion in subjects with suspected malabsorption. Plasma acetate levels increased during fat infusion, and conversely, fell with suppression of fatty acid levels during euglycaemic clamping. Insulin appeared to promote acetate production from glucose by enhancing glycolysis and acetyl CoA availability, although its activity in reducing lipolysis had an opposite effect. The hepatic formation of acetate from ethanol did not appear influenced by prior chlorpropamide intake. Glucose tolerance was unaffected by a 150mmol/hr acetate load, but acetate tolerance was impaired when glucose was simultaneously available. Adipose tissue lipolysis was suppressed during acetate infusions as evident from reduced levels of glycerol and non-esterifled fatty acids. Blood 'ketone body' levels were increased, suggesting direct conversion from acetate. Possibly as a result, fat oxidation assessed from gaseous exchange, was reduced with infused acetate. Acetate utilization was impaired in diabetic patients from higher fasting plasma levels and slower metabolic clearance. The defect in diabetes was probably due to both over-production and under-utilization, and could be related to the enhanced lipolysis, hyperglycaemia and a reportedly reduced hepatic activity of acetyl CoA synthetase. It was concluded that acetate is derived from both colonic fermentation and endogenous catabolism of glucose and fatty acids and appears rapidly metabolisable in humans. Some areas of further interest in human acetate metabolism were highlighted.
25

Synthesis of Glitazone Analogues as Anti-Diabetic Drugs

Tshiluka, Ndivhuwo Raymond 21 September 2018 (has links)
MSc (Chemistry) / Department of Chemistry / In this study, three series of novel glitazones (acetates, glycinates and alaninates) were designed and prepared by using appropriate synthetic methods to incorporate aromatic ring, alicyclic amines and alanine moiety instead of glycine moiety as a linker via two carbons. This was done over five reaction steps. Compounds were synthesized using conventional methods from step one with nucleophilic substitution to Knoevenagel condensation reaction as the final step and were characterized by using a combination of 1H NMR, 13C NMR, IR spectroscopies as well as HRMS analysis. Fourteen final compounds were successfully obtained in good to excellent yields. Furthermore, the same compounds were subjected to in vitro screening for their inhibitory activities against α-glucosidase and α-amylase. Among all the synthesized compounds, 36f exhibited excellent antidiabetic activities against α-glucosidase. Compounds 36a, 36b, 36i and 36j also displayed good activities and have potential to be further investigated whereas compounds 36c, 36e, 36g and 36h exhibited moderated activities against α-glucosidase. Only compounds 36a, 36b, 36f, 36i and 36j displayed weak activities against α-amylase and the rest of the compounds were not active at all against α-amylase. / NRF
26

Examination of variables that affect dyeing of acetate in a three dye system

Winfrey, Elizabeth Lea 07 July 2010 (has links)
This research evaluated three variables within an AATCC experimental laboratory procedure for dyeing acetate. Evaluation of color measurement from test samples and transmission, an indicator of dye exhaustion, from final dyebath was focused on reproducibility of color from dyeing to dyeing and maximum dye exhaustion. Experimental effects were 1) pH of dyebath, 2) high dyeing temperature for the test fabric, an acetate tricot, and 3) time at the high dyeing temperature. Major findings included: 1. pH of 4 produces significantly higher X and Y color reflectance values, measured by the Color Eye<sup>R</sup> at the .05 level. pH of 4 and 6 produce significantly higher Z color values at the .05 level. Transmission readings, measured by the Spec 20<sup>R</sup>, indicate exhaustion for the Disperse Red 4, Disperse Blue 3, and Disperse Yellow 3 dyes and are significantly higher for pH of 4 at the .05 level. 2. Temperature of (150°F) 65.6°C and (175°F) 79.4°C give significantly higher transmission readings for Disperse Red 4 at the .05 level. (175°F) 79.4°C and (200°F) 82°C give significantly higher transmission readings for Disperse Blue 3 at the .05 level. Disperse Yellow 3 is unaffected by temperature. 3. Time at the high dyeing temperature had no effect on color measurements or transmission. 4. Transmission is a qualitative indicator of dye concentration and exhaustion. 5. Leakage was prevented with one time use of Ball Jar Lids<sup>R</sup> on the AATCC Wash Cups IIA used on the Atlas LaundryOmeter.<sup>R</sup> / Master of Science
27

A study of the difference between the primary and secondary cellulose acetates

Tannenbaum, Irving R. January 1947 (has links)
M.S.
28

An investigation into the molecular mechanism of action of the progestins, medroxyprogesterone acetate and norethisterone acetate

Koubovec, Dominique J. B. M. 04 1900 (has links)
Thesis (PhD)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: Although the progestins medroxyprogesterone acetate (MPA) and norethisterone acetate (NET-A) are widely used in reproductive therapy, the steroid receptors and their target genes involved in the actions of MPA and NET-A are not well understood. Surprisingly, it had not yet been investigated whether doses of MPA and NET-A used for contraception and HRT cause significant side effects through various target genes via the glucocorticoid receptor (GR). In this thesis results of in vitro studies showed that, MPA, like dexamethasone (dex) and prog, significantly repressed tumour necrosis factor (TN F)-stimulated IL-6 protein production, and IL-6 and IL-8 promoter reporter constructs at the transcriptional level in L929sA cells, via interference with nuclear factor KB (NFKB) and activator protein-1 (AP-1) transcription factors. Like dex and prog, MPA did not affect NFKB DNA-binding activity. Furthermore, unlike dex and prog, MPA did not inhibit mitogen-activated protein kinase (MAPK) activity. The antagonistic effects of the GR and progesterone receptor (PR) antagonist, RU486, as well as the MPAinduced nuclear translocation of the GR, strongly suggest that the actions of MPA in these cells are mediated at least in part via the GR. Although the mechanism was not investigated as extensively as for MPA, NET-A was shown to repress IL-8 promoter reporter activity very weakly relative to dex, MPA and prog in Hek293 cells stably transfected with the rat GR. Furthermore, NET-A, like MPA, dex and prog did not interfere with the DNA-binding activity of NFKB. Significant transactivation of a GRE-driven promoter reporter construct by MPA and dex in L929sA via endogenous GR and COS-1 cells via expressed rat GR, and by MPA, dex and prog in Hek293 cells via expressed rat GR was also observed. In contrast, NET-A, unlike MPA, dex and prog showed no transactivation in Hek293 cells. MPA, NET-A and prog were shown to compete with dex for binding to the endogenous human GR in human lung carcinoma A549 cells. Similarly, MPA and NET-A were shown to compete with dex for binding to expressed rat GR in COS-1 cells. MPA displayed a higher relative binding affinity than NET-A for the GR in both systems, and a higher relative binding affinity than prog in A549 cells. Equilibrium dissociation constants (Ki values) for MPA (Ki = 10.8 ± 1.1 nM), NET-A (Ki = 270 ± 1.3 nM) and prog (Ki = 215 ± 1.1 nM) towards the human GR in A549 cells were also established. Furthermore, dose-response curves showed that MPA displays significantly greater GC agonist potency and efficacy than NET-A and prog for both transactivation of a synthetic GRE-reporter construct and transrepression of a synthetic IL-8 reporter construct via expressed rat GR in Hek293 cells, as NET-A showed no transactivation and very weak partial agonist activity for transrepression. Based on these observations, MPA behaves as a GR agonist whereas NET-A is proposed to be a weak antagonist. These results show that MPA and NET-A are not alike and not the same as prog in their mechanism of action via the GR, which may have serious health implications in vivo. Such insights may provide women and their clinicians with more information to facilitate the selection of contraception or reproductive therapy regimes with fewer side effects. / AFRIKAANSE OPSOMMING: Alhoewel MPA en NET-A algemeen gebruik word in hormoontherapie, is dit nie duidelik watter steroïedreseptore en teikengene betrokke is by die werking van MPA en NET-A nie. Verrassend is dat geen studie nog gedoen is om te bepaal of die dosisse van MPA en NET-A wat gebruik word in voorbehoeding en hormoonvervangingsterapie (HVT), newe-effekte veroorsaak deur die glukokortikoïedreseptor (GR) en verskeie teikengene nie. In hierdie tesis is in L929sA selle aangetoon dat MPA, net soos deksametasoon (dex) en prog, TNF-gestimuleerde IL-6 produksie onderdruk, en dat IL-6 en IL-8 promoter-rapporteerderkonstrukte op transkripsionele vlak onderdruk word deur middel van inmenging met NF-KB en AP-1 transkripsie-faktore. Net soos dex en prog het MPA nie die DNA-bindingsaktiwiteit van NF-KB beïnvloed nie. Anders as dex en prog het MPA egter nie MAPK aktiwiteit onderdruk nie. Die antagonistiese effekte van RU486, asook die MPA-geïnduseerde translokasie van die GR na die selkern, dui sterk daarop dat die effekte van MPA in hierdie selle ten minste gedeeltelik deur die GR geskied. Alhoewel die meganisme vir NET -A nie so breedvoerig bestudeer is as dié van MPA nie, is tog aangetoon dat, in Hek293 selle wat stabiel getransfekteer is met die rot GR, die onderdrukking van die IL-8 promoter deur NET-A baie swakker is as met dex, prog en MPA. Verder is daar ook gevind dat NET-A, net soos MPA, dex en prog, nie kon inmeng met die DNA-bindingsaktiwiteit van NF-KB nie. Beduidende transaktivering van 'n GRE-bevattende promoterrapporteerderkonstruk deur MPA en dex in L929sA en COS-1 selle, en deur MPA, dex en prog in Hek293 selle, is ook gevind. Daarteenoor het NET-A, anders as MPA, dex en prog, geen transaktivering in Hek293 selle getoon nie. Verder moes die relatiewe bindingsaffiniteit (ewewigs-dissosiasiekonstantes) van MPA, NET-A en prog vir die GR, asook die relatiewe sterkte en effektiwiteit vir transaktivering en transonderdrukking van verskeie teikengene deur die GR, ook bepaal word. Daar is gevind dat MPA, NET-A en prog meeding met dex vir binding aan die endogene GR in mens longkarsinoom A549 selle. Soortgelyk hieraan is ook gevind dat MPA en NET-A meeding met dex vir binding aan rot GR wat in COS-1 selle uitgedruk is. MPA het in beide sisteme 'n hoër relatiewe bindingsaffiniteit vir die GR getoon as NET-A, asook 'n hoër relatiewe bindingsaffiniteit as prog in A549 selle. Ewewigs-dissosiasiekonstantes (Ki waardes) vir MPA (Ki = 10.8 ± 1.1 nM), NET- A (Ki = 270 ± 1.3 nM) en prog (Ki = 215 ± 1.1 nM) vir die mens GR in A549 selle is ook bereken. Dosisrespons-grafieke het ook aangedui dat MPA 'n beduidend beter GC sterkte en effektiwiteit as NET-A en prog het, vir beide transaktivering van 'n sintetiese GRE-rapporteerderkonstruk en transonderdrukking van 'n sintetiese IL-8 rapporteerderkonstruk via rot GR wat uitgedruk is in Hek293 selle. Dit kon afgelei word aangesien NET-A geen transaktivering en slegs baie swak gedeeltelike agonisaktiwiteit vir transonderdrukking getoon het. Op grond van hierdie waarnemings tree MPA op as 'n GR agonis, terwyl dit lyk asof NET-A 'n swak antagonis is. Hierdie resultate dui aan dat MPA en NET-A nie dieselfde is nie, en ook nie dieselfde meganisme van werking deur die GR het as prog nie. Dit kan ernstige gesondheidsimplikasies inhou in vivo. Hierdie insigte kan dus meer inligting aan vroue en kliniese personeel verskaf om sodoende die keuse van voorbehoeding of voortplantingsterapie met minder newe-effekte te vergemaklik.
29

Central carbon metabolism of the biocontrol yeast Pichia anomala : influence of oxygen limitation /

Fredlund, Elisabeth, January 2004 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2004. / Härtill 5 uppsatser.
30

Complexes of cupric ion with acetate and glycinate ions in aqueous solution ...

Draley, Joseph Edward, January 1946 (has links)
Thesis (Ph. D.)--Catholic University of America. / Processed. eContent provider-neutral record in process. Description based on print version record. Bibliography: p. 135-137.

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