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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.
1

Enhanced butyric acid fermentation by Clostridium tyrobutyricum immobilized in a fibrous-bed bioreactor

Zhu, Ying. January 2003 (has links)
Thesis (Ph. D.)--Ohio State University, 2003. / Title from first page of PDF file. Document formatted into pages; contains xx, 323 p. Includes abstract and vita. Advisor: Shang-Tian Yang, Dept. of Chemical Engineering. Includes bibliographical references (p. 263-288).
2

Responses of processing peas to applications of 4-(2-methyl-4-chlorophenoxy) butyric acid

Vostral, Henry Joseph, January 1965 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1965. / Typescript. Vita. Description based on print version record. Includes bibliographical references.
3

Interrelationships between ketone body production, carbohydrate utilization and fat mobilization in the ruminant

Menahan, Lawrence Albert, January 1966 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1966. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
4

'n Studie oor die aktiwiteit van 'n seolietkatalisator met betrekking tot die isomerisasie van hekseen

Coetzee, Johannes Hendrik 22 October 2015 (has links)
M.Sc. (Chemistry) / At Sasol the zeolite catalyst HZ-1 is used to isomerize short-chain hydrocarbons. In this reaction unwanted organic acids are also formed. This investigation has as focal point the interaction between one of these acids, n-butyric acid, and the catalyst. This experimental study consisted of kinetic experiments with a continuous reactor as well as a pulse reactor. In addition to this, temperature programmed desorption was used ...
5

The C₄-saccharinic acids. Further attempts to prepare 2, 2-́dihydroxyisobutyric acid. 2, 3-dihydroxybutyric acid lactone from glycidol. The preparation of the two iodohydrins of glycerol ...

Klaas, Rosalind Amelia, January 1933 (has links)
Part of Thesis (PH. D.)--University of Chicago, 1932. / "Private edition, distributed by the University of Chicago libraries, Chicago, Illinois." eContent provider-neutral record in process. Description based on print version record.
6

The C₄-saccharinic acids. Further attempts to prepare 2, 2-́dihydroxyisobutyric acid. 2, 3-dihydroxybutyric acid lactone from glycidol. The preparation of the two iodohydrins of glycerol ...

Klaas, Rosalind Amelia, January 1933 (has links)
Part of Thesis (PH. D.)--University of Chicago, 1932. / "Private edition, distributed by the University of Chicago libraries, Chicago, Illinois." eContent provider-neutral record in process. Description based on print version record.
7

I. Studies on ring closure of [Gamma]- (1- and 2-napthyl)-butyric acid II. 7-acetoxy-9-acetyl-1, 2, 3, 4,- tetrahydrophenanthrene and dialkylamino carbinols derived from it ...

Mighton, Harold Russell, January 1900 (has links)
Thesis (Ph. D.)--Columbia University, 1945. / "Contribution from the Department of chemistry of Columbia university." "Lithoprinted." Vita. Bibliography: p. 16, 27.
8

Production of butyric acid and hydrogen by metabolically engineered mutants of Clostridium tyrobutyricum

Liu, Xiaoguang 24 August 2005 (has links)
No description available.
9

Butyric and docosahexaenoic acids production from hemicellulose

Zhang, Ling January 1900 (has links)
Master of Science / Department of Biological and Agricultural Engineering / Wenqiao Yuan / Many of the current industrial fermentation processes cannot use pentose as the carbon source. However, complete substrate utilization of sugars in lignocellulose is one of the prerequisites to render economic development of biofuels or bioproducts from biomass. In this study we proposed a new process for DHA production from renewable carbon sources by first using anaerobic bacteria, Clostridium tyrobutyricum to convert pentose into organic acids with butyric acid as the main product, and then using the organic acids to feed microalgae, Crypthecodinium cohnii to produce DHA. The effect of glucose and xylose on the yield of butyric acid produced by C. tyrobutyricum was investigated, separately. Cell growth of C. tyrobutyricum increased with increasing initial glucose or xylose concentration, but was not affected significantly when the concentration was above 55g/l for glucose or 35g/l for xylose. Butyric acid yield increased as the initial sugar concentration increased in both xylose and glucose, but the conversion rate from xylose or glucose to butyric acid decreased as the sugar concentration increased. The xylose to glucose ratio in their mixture did not significantly affect cell growth or butyric acid yield. The effect of arabinose on the yield of butyric acid produced by C. tyrobutyricum was also studied. As for butyric acid production, compared with glucose or xylose, the arabinose was in a low efficiency, with butyric acid output of 2.25g/l in 10g/l arabinose and a long lag period of about 3-4 d. However, a low concentration of arabinose could be used as a nutritional supplement to improve the fermentability of a mixture of xylose and glucose. The conversion rate of sugar to butyric acid increased as the supplement arabinose increased. In order to obtain low cost xylose, corncobs were hydrolyzed and this xylose-rich product was used to culture C. tyrobutyricum. The results showed that at end of the 9 d fermentation, the concentration of butyric acid from corncob hydrolysate reached 10.56 g/l, and the mimic medium reached 11.3 g/l. This suggests that corncob hydrolysate can be used as a carbon source for butyric acid production by C. tyrobutyricum, although some inhibitory effects were found on cell growth with corncob hydrolysate. The effect of butyric acid, lactic acid and acetic acid on the yield of DHA produced by C. cohnii was also investigated, separately. The DHA yield was highly related to both biomass and DHA content in the cell, whereas lower growth rate could bring higher DHA content. The best concentration for DHA yield seemed to be 1.2g/l in three single organic acid media. In two organic acids mixture media, acetic acid tended to be beneficial for biomass accumulation, regardless whether butyric acid or lactic acid was mixed with acetic acid, the OD could reach 1.3 or above. When butyric acid was mixed with lactic acid, the highest DHA yield was achieved, due to increased DHA content from mutual influence between butyric acid and lactic acid.
10

Short-chain fatty acid modulation of apoptosis in gastric and colon cancer cells.

Matthews, Geoffrey Mark January 2007 (has links)
Introduction: Gastric and colon cancer are major causes of mortality and morbidity worldwide. Gastric cancer is often detected at an advanced stage and current chemotherapeutics are only modestly effective against this neoplasm. Novel chemotherapeutics, chemopreventive agents and treatment strategies are required to prevent and treat gastric cancer. The ideal method to eliminate cancer cells may be the induction of apoptosis, further preventing cell proliferation and tumour growth. Recently, short-chain fatty acids (SCFAs) butyrate and propionate have been investigated as potential chemotherapeutic agents, particularly in colon cancer. Butyrate is reported to induce apoptosis in colon cancer cells and is demonstrated to modulate intracellular redox state by altering the levels of an antioxidant, glutathione (GSH). GSH availability is controlled by the oxidative pentose pathway (OPP). Very few studies have investigated the effects of butyrate on cell types other than colon cancer cells, and even less is known regarding the effects of propionate. This thesis investigated the potential for SCFAs to induce apoptosis in a gastric cancer cell line, Kato III, compared to the colon cancer cell line, Caco-2. Cell cycle regulation, OPP activity, GSH availability and glucose metabolism were also assessed. Methods: Initial studies developed a new technique to measure 1-13C-D-glucose metabolism. Following this, Kato III and Caco-2 colon carcinoma cells were treated with butyrate or propionate (1mM, 5mM or 10mM) or a 5mM combination of both SCFAs. The induction of apoptosis and cell cycle alterations by these SCFAs were assessed using flow cytometry. OPP activity and GSH availability were assessed in both cell lines using colorimetric techniques. Butyrate metabolism was assessed using 13C-butyrate. Results: Butyrate and propionate significantly induced apoptosis and G2-M arrest in Kato III and Caco-2 cells, although to a significantly greater extent in the latter cell line. Moreover, butyrate induced apoptosis to a significantly greater extent than propionate, in both cell lines. SCFA treatment led to the significant up-regulation of OPP activity in both cancer cell lines while GSH availability was significantly reduced. Glucose metabolism was initially increased by all SCFA treatments, however, 72hr butyrate treatment led to its reduction. Importantly, glucose metabolism was measured using a new technique developed within this thesis. The rate of butyrate metabolism was demonstrated to correlate with the sensitivity of each cell line to this SCFA. Conclusions: This thesis provides evidence that SCFAs, particularly butyrate, induce apoptosis in gastric and colon cancer cells in vitro. The response of cancer cells to SCFAs appears complex, and involves multiple distinct mechanisms and pathways, including p53, Fas, changes to intracellular redox state and glucose metabolism. The capability of butyrate to induce apoptosis also appears to be directly related to the rate of its metabolism. Butyrate has the potential to be utilised as an adjunctive therapy for the treatment of gastric cancer and colon cancer. / Thesis (Ph.D.) -- School of Molecular and Biomedical Science, 2007

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