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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

Analysis of flavan-3-ols by capillary electrophoresis.

January 2004 (has links)
Lee Wai Hang. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 71-76). / Abstracts in English and Chinese. / Acknowledgement --- p.i / Abstract --- p.ii / Table of Contents --- p.v / Abbreviations --- p.viii / List of Figures --- p.ix / List of Tables --- p.xiv / Chapter / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- The French Paradox --- p.1 / Chapter 1.2 --- Flavonoids --- p.2 / Chapter 1.3 --- Grape seed extract --- p.4 / Chapter 1.4 --- Instrunmental analysis --- p.7 / Chapter 1.4.1 --- High Performance Liquid Chromatography --- p.7 / Chapter 1.4.2 --- Colorimetry --- p.9 / Chapter 1.5 --- Capillary Electrophoresis --- p.10 / Chapter 1.5.1 --- Instrunmentation --- p.10 / Chapter 1.5.2 --- Electroosmotic Flow --- p.11 / Chapter 1.5.3 --- Electrophoretic mobility --- p.13 / Chapter 1.6 --- Objective of the study --- p.15 / Chapter 2. --- Experimental --- p.18 / Chapter 2.1 --- Reagents and material --- p.18 / Chapter 2.1.1 --- Reagents --- p.18 / Chapter 2.1.2 --- Instrunmentation --- p.18 / Chapter 2.1.3 --- Reference compounds --- p.19 / Chapter 2.1.4 --- Samples --- p.19 / Chapter 2.2 --- Selection of solvent for sample preparation --- p.20 / Chapter 2.3 --- Procedures --- p.21 / Chapter 2.3.1 --- Preparation of running buffer solution --- p.21 / Chapter 2.3.2 --- Preparation of standard solution --- p.21 / Chapter 2.3.3 --- Preparation of sample solution --- p.22 / Chapter 2.3.4 --- Flushing procedures --- p.22 / Chapter 3. --- Results and Discussion --- p.24 / Chapter 3.1 --- Preliminary experiments --- p.24 / Chapter 3.2 --- Effect of pH --- p.27 / Chapter 3.3 --- Addition of surfactant --- p.30 / Chapter 3.4 --- Effect of SDS concentration --- p.35 / Chapter 3.5 --- Addition of cyclodextrins --- p.39 / Chapter 3.6 --- Urea --- p.46 / Chapter 3.7 --- Addition of organic modifier --- p.47 / Chapter 3.8 --- Effect of borate concentration --- p.49 / Chapter 3.9 --- Effect of cyclodextrin concentration --- p.53 / Chapter 3.10 --- Optimized condition --- p.58 / Chapter 3.11 --- Reproducibility of the method --- p.58 / Chapter 3.12 --- Quantitative analysis of reference compounds --- p.60 / Chapter 3.13 --- Application of the CE method in grape seed products --- p.62 / Chapter 4. --- Conclusion --- p.69 / References --- p.71
22

The isolation and characterisation of pharmacologically active compounds isolated from medicinal plants

Bergendorff, Ola. January 1994 (has links)
Thesis (doctoral)--Lund University, 1994. / Added t.p. with thesis statement inserted.
23

The isolation and characterisation of pharmacologically active compounds isolated from medicinal plants

Bergendorff, Ola. January 1994 (has links)
Thesis (doctoral)--Lund University, 1994. / Added t.p. with thesis statement inserted.
24

The effect of acute consumption of a flavonol-rich cocoa drink on cerebral vasomotor reactivity in African Americans

Ku, ByungMo 08 October 2014 (has links)
African Americans (AA) are at great risk of cardiovascular diseases (CVD) which can lead to brain damage, dementia, and endothelial dysfunction. Decreased nitric oxide (NO) bioavailability contributes cardiovascular disease in AA population. Flavonols of the subclass known as flavonoids that have several beneficial effects on cerebral blood flow and cerebral vasomotor reactivity (CVMR). This study investigated the effects of the acute consumption of a flavanol-rich cocoa drink on CVMR. Ten non-smoking African American (6 males and 3 females) participants were randomly recruited. The subjects participated in two experimental sessions which were separated before and after the consumption of cocoa drink. For the pre-session, baseline CVMR was measured by the hypercapnia rebreathing (CVMR test) prior to the consumption of the cocoa drink and the again at 2h after consumption of one serving of the cocoa drink (45g of cocoa mixed with 8oz of cold water). Cerebral vascular conductance (CVC) was significantly increased in the post-study during hypercapnia rebreathing compared with the pre-study(post-study: 3.649 ± 1.833 CVC % of baseline/mmHg, pre-study: 2.483 ± 1.418 CVC % of baseline/mmHg vs. P < 0.05) Thus, CVMR was significantly increased in the post-study after the acute consumption of a flavonol-rich cocoa drink compared to the pre-study in AA. / text
25

Synthesis of intermediates for chalcone and 6-MSA biosynthesis

Schicker, Susanna Heidi January 1997 (has links)
No description available.
26

Chemosystematic studies of the tribe Mimoseae (Mimosoideae)

Sulaiman, Shaida Fariza January 1997 (has links)
No description available.
27

Antioxidants of licorice

An, Jing January 1993 (has links)
No description available.
28

Phytochemical and biological studies of Tagetes erecta and its clinical evaluation in the treatment of hallux abducto valgus and its associated condition, bunion

Khan, Mohammed Taufiq January 1999 (has links)
No description available.
29

The structure and synthesis of metabolites from virgilia oroboides and chlorophora excelsa (Iroko)

Swinny, Ewald Eugene. 11 November 2013 (has links)
In the present study the acetone extract of the heartwood of two trees, Virgilia oroboides and Chlorophora excelsa, were investigated. The heartwood of Virgilia oroboides afforded a variety of known flavonoids, as well as a new pterocarpene and a new α-hydroxydihydrochalcone, viz.; 3-hydroxy-8, 9-methylenedioxy-6a,11a-dihydropterocarpan (αS), 2' ,4'-trihydroxy-4-methoxydihydrochalcone. A series comprising substituted hydroxygeranylstilbenes, substituted benzenoid compounds and quercitin-type flavones were isolated from the acetone extract of the heartwood of Chlorophora excelsa. The new compounds isolated from this tree are: 3,5-dihydroxy-4-geranylbenzaldehyde; 3' ,4,5'-trihydroxy-4'-geranylstilbene; 2'-methoxy-3, 4',7-tri-O-methylquercitin. A combination of solvent extraction, Craig countercurrent, column (LH 20 and silica gel) and thin layer chromatography procedures were used to isolate and purify the compounds mentioned. Structures were elucidated by high resolution (300 MHz) ¹HNMR spectroscopy (including NOE and spin-spin decoupling experiments) and mass spectrometry. The proposed structural assignments of the following compounds were confirmed by synthesis: 3, 5-dihydroxy-4-geranylbenzaldehyde; 3' ,4 ,5'-trihydroxy-4' -geranylstilbene; 2 ,3' ,4 ,5'-tetrahydroxy-4' -geranylstilbene (chlorophorin). The modified Wittig reation was used to synthesize 3' ,4 ,5' trihydroxystilbene. U.V. irradiation experiments were performed on chlorophorin in an attempt to synthesize the cis-isomer and a phenanthrene-type compound. Biosynthetic pathways showing the structural relationships of the identified compounds in Virgilia oroboides and Chlorophora excelsa were proposed. An attempt to synthesize (+)-catechin lignoid involved the coupling of (+)-catechin to sinapyl alcohol, with the latter synthesized from 2 ,6-dimethoxyphenol via vinyl quinone methide. Further investigations on lignoid currently in progress. / Thesis (M.Sc.)-University of Durban-Westville, 1989.
30

The transport of the Rooibos tea flavonoid aspalathin across the skin and the intestinal epithelium

Huang, Miao-Juei January 2006 (has links)
A dissertation submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master in Pharmacy. Johannesburg, South Africa, 2006 / The aqueous extract of rooibos has been used for more than three hundred years since its discovery by the indigenous people. Currently, rooibos is gaining popularity in the cosmetic industry and incorporation of rooibos extracts in topical cosmetic formulations has become a fashionable trend. Both topical and intestinal absorption of rooibos tea were investigated. The transport of aspalathin in the unfennented (green) rooibos aqueous extracts and aqueous solution of pure aspalathin were studied. / IT2018

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