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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.
11

Effects of Carbon Dioxide Levels on Growth and Pigments of Freshwater Algae

Unknown Date (has links)
This project was designed to investigate the effects of carbon dioxide (CO2) levels on the growth and pigment ratios (chemotaxonomy) of freshwater algal species typical to the south Florida surface waters. Green algae, diatoms, and cyanobacteria were cultured under 400 or 800 ppm CO3 in air for several weeks. Growth monitoring used a cell counter, hemocytometer, and chlorophyll fluorescence. Pigments were analyzed using HPLC-PDA. Experiments with certified CO2 concentrations (400, 600, 800, 1200 ppm) were conducted with helium degassed ultrapure water and each of three culture media. Theoretical and experimental pH values with water matched exactly. However, each culture media proved to exhibit significant buffer capacity. Cell growth monitoring was problematic except for the cyanobacterium Microcystis aeruginosa. That species responded to increased CO2 (800 ppm) with increased growth rates as predicted. The other species gave erratic results mainly due to difficulties in obtaining valid consistent cell counts. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection
12

Beitrag zur zerstörungsfreien Bestimmung des räumlichen Konzentrationsprofils von Chromophoren in biologischen Geweben mittels photoakustischer Spektroskopie /

Schmidt, Kai, January 2000 (has links)
Thesis (doctoral)--Universität der Bundeswehr, München, 2000. / Includes bibliographical references (p. 165-172).
13

Studies of the Membrane and DNA Gyrase Inhibiting Antibiotics on Pigment Synthesis in Corynebacterium Poinsettiae

Tabarya, Daniel 08 1900 (has links)
The purpose of this study was (1) to determine whether a correlation exists among the protein profiles, extracted from cell membranes of mutants belonging to five pigment cluster groups, (2) to locate the protein moiety and cartenoprotein complex in the membranes of wild type and colorless mutant (designated W-19) of C. poinsettae and to show whether there are any structural differences between cell membranes of the wild type and a colorless mutant, (3) to determine the effect of six antibiotics on cartenoid gene expression.
14

Synthetic and spectroscopic studies of 6-substituted chromone derivatives

Ramonetha, Thata Golden 05 1900 (has links)
Department of Chemistry / MSc (Chemistry) / See the attached abstract below
15

Synthetic studies and biological evaluation of chromone - 3 - carbaldehydes

Gordon, Allen Tauya 21 August 2018 (has links)
MSc (Chemistry) / Department of Chemistry / Chromones are well known naturally occurring heterocyclic compounds with oxygen as a heteroatom. Chromones are also one of the major classes of naturally occurring compounds, and the interest in their chemistry is due to their wide range of their biological activity. In this study, three classes of target compounds were synthesized through three different pathways. The first pathway, chromone-3-carbaldehyde analogues were afforded in good to excellent yield followed by the oxidation thereof to 4-oxo-4H-chromene-3-carboxylic acids. A series of chromone-3-carboxamides was obtained from corresponding 4-oxo-4H-chromene-3-carboxylic acid via the in situ generation of the corresponding acid chloride in good yield. The second class of compounds were achieved by reacting corresponding chromone-3-carbaldehyde analogues with thiazolidine-2,4-dione to afford 5-((4-oxo-4H-chromen-3-yl)methylene)thiazolidine-2,4-dione analogues. The third class of compounds followed the same reaction pathway as the second class of compounds from corresponding 8-allyl-chromone-3-carbaldehyde analogues to afford 5-((8-allyl-4-oxo-4H-chromen-3-yl)methylene)thiazolidine-2,4-dione analogues in good yield. Compounds were characterized by 1D NMR (1H, 13C and DEPT), 2D NMR (COSY, HSQC and HMBC), IR and elemental analysis (CHN analysis). Selected synthesized chromone derivatives were evaluated in vitro for two biological assays; namely trypanocidal activity and cytotoxicity. Among all tested compounds, 41A, 55B and 63D displayed promising trypanocidal activity by reducing the percentage parasite viability to 0.61, 0.15 and 0.21 respectively. These results were further substantiated by their IC50 values 4.3, 1.3 and 1.9 μg/mL respectively. Compounds 41B and 59A also showed significant trypanocidal activity, however it was below the positive control. Compounds 41A and 55B displayed cytotoxicity against the HeLa cells whilst compound 63D displayed no toxicity against the HeLa cells. / NRF

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