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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.
911

Intercalation of fatty acids into layered double hydroxides

Nhlapo, N.S. (Nontete Suzan) 02 October 2009 (has links)
Surfactant-mediated intercalation of aliphatic fatty acids into a commercial,layered double hydroxide (LDH) with the approximate composition of [Mg0.689Al0.311(OH2)] (CO3)0.1569nH2O was explored. The reactions were conducted at elevated temperatures with the LDH powder suspended in a fatty acid oil-water emulsion. The acidic fatty acid, e.g. stearic acid, reacts with the basic carbonate anions from LDH-CO3. In the process, CO2 is released as a gas and the fatty acids are intercalated as a bilayer. A high concentration of anionic or non-ionic surfactants, i.e. sodium dodecylsulphate or Tween 60, facilitates the intercalation process by emulsifying the molten fatty acids and dispersing the LDH particles. The presence of carboxylate anions in the interlayer region was confirmed by the carboxylate absorption peaks observed in the region 1700–1000 cm-1 on Fouriertransform infrared spectroscopy (FT-IR). Several bands were observed, i.e. ionised and non-ionised. An increase in the d-spacing of the d003 plane of the brucite-like LDH layers was observed on X-ray diffraction (XRD) analysis of all the LDH intercalates. The d-spacing increased linearly with the length of the carboxylic acid chain. Sharp reflection peaks were obtained on XRD, showing the high crystallinity of the LDH intercalates. The thermal decomposition of these materials was explored on thermogravimetric or differential thermogravimetric analysis (TGA/DTA) and temperature-scanned XRD. The mole ratio of Mg to Al was obtained by XRF and the morphology by scanning electron microscopy (SEM). The present method works well with long-chain aliphatic fatty acids at temperatures above or at the melting point of the desired acid. Temperature proved to be the most important parameter to control during the preparation process, i.e. at low temperatures incomplete reactions were obtained. The method is convenient, economical and environmentally friendly. It employs the readily available carbonate form of LDH as a starting reagent, water is used as medium rather than organic solvents, there are no high-temperature calcinations, and an inert atmosphere is not required. Copyright / Dissertation (MSc)--University of Pretoria, 2008. / Chemistry / unrestricted
912

Deep Sequencing of the Mexican Avocado Transcriptome, an Ancient Angiosperm with a High Content of Fatty Acids

Ibarra-Laclette, Enrique, Méndez-Bravo, Alfonso, Pérez-Torres, Claudia Anahí, Albert, Victor A., Mockaitis, Keithanne, Kilaru, Aruna, López-Gómez, Rodolfo, Cervantes-Luevano, Jacob Israel, Herrera-Estrella, Luis 13 August 2015 (has links)
Background: Avocado (Persea americana) is an economically important tropical fruit considered to be a good source of fatty acids. Despite its importance, the molecular and cellular characterization of biochemical and developmental processes in avocado is limited due to the lack of transcriptome and genomic information. Results: The transcriptomes of seeds, roots, stems, leaves, aerial buds and flowers were determined using different sequencing platforms. Additionally, the transcriptomes of three different stages of fruit ripening (pre-climacteric, climacteric and post-climacteric) were also analyzed. The analysis of the RNAseqatlas presented here reveals strong differences in gene expression patterns between different organs, especially between root and flower, but also reveals similarities among the gene expression patterns in other organs, such as stem, leaves and aerial buds (vegetative organs) or seed and fruit (storage organs). Important regulators, functional categories, and differentially expressed genes involved in avocado fruit ripening were identified. Additionally, to demonstrate the utility of the avocado gene expression atlas, we investigated the expression patterns of genes implicated in fatty acid metabolism and fruit ripening. Conclusions: A description of transcriptomic changes occurring during fruit ripening was obtained in Mexican avocado, contributing to a dynamic view of the expression patterns of genes involved in fatty acid biosynthesis and the fruit ripening process.
913

Omega-3 Fatty Acid Fortification of Marinara Sauce

Collie, Hannah 01 May 2021 (has links)
In westernized culture, there is a deficit of healthy fats in the average person’s diet. Decreased intake of omega-3 fatty acids has been correlated to many different conditions such as cardiovascular disease, cancer, and chronic inflammatory issues. The “Mediterranean Diet” has been proposed as an ideal way to combat these issues. This diet promotes fish as a protein source and as a way to increase intake of essential polyunsaturated fatty acids. Due to location and dietary trends, fish is less often the main component of Northeast Tennessee's diet. This study investigated ways to fortify a more commonly consumed food in western culture, marinara sauce, with flaxseed oil, walnut oil, or anchovies. These fortified marinara sauces were compared to a commercial sauce, Paul Newman’s Marinara. We hypothesized that adding omega-3 rich ingredients to a base marinara sauce recipe will significantly vary the fatty acid profile and increase the amount of omega-3 fatty acids and decrease the omega-6 to omega-3 fatty acid ratio. Marinara sauces were prepared and analyzed using proximate analysis methods to evaluate each variant sauce for macronutrient distribution. Preparation included cooking, freeze-drying, and grinding the variants into a fine powder. The tests that we performed included: bomb calorimetry, Kjeldahl protein analysis, Soxhlet fat analysis, ash/mineral analysis, FRAP Assay of antioxidant content, and gas chromatography to characterize fatty acid profiles. The focus of our proximate analysis was investigating the fatty acid composition to answer our main research question. Other tests conducted allowed us to understand better the nutrient composition of the 3 variants for possible future studies. The three variants showed a better omega-6 to omega-3 fatty acid ratio than the Paul Newman’s sauce. Samples with the highest to lowest omega-6 to omega-3 ratio were Paul Newman's Marinara, Anchovies, Walnut Oil, Flaxseed Oil, respectively. Gas chromatography showed different concentrations of omega-3 fatty acids as (% area under the curve): flaxseed oil (32.42%), walnut oil (7.637%), anchovies (3.018%), and Paul Newman’s Marinara (1.599%). All three variant sauces, flaxseed oil, walnut oil, and anchovy, compared to the commercial Paul Newman's sauce, had better omega-3 fatty acid content and lower omega-6 to omega-3 ratio. In conclusion, simple additions of omega-3 ingredients to marinara sauce could decrease the omega-6 to omega-3 ratio in the diet.
914

Immunohistochemical Detection of a Fatty Acid Synthase (OA-519) as a Predictor of Progression of Prostate Cancer

Shurbaji, M. Salah, Kalbfleisch, John H., Thurmond, T. Scott 01 January 1996 (has links)
Prostate cancer is the most common newly diagnosed non-skin cancer and the second leading cause of cancer death in men. It is a unique neoplasm because of the large discrepancy between its clinical incidence and the much higher incidence of latent cancer. Predicting the prognosis of prostate cancer, especially the cancers detected incidentally or by screening, remains a clinically important problem. Immunoreactivity for Onco-antigen 519 (OA- 519), a recently described fatty acid synthase (FAS), has been associated with poor prognosis in breast cancers. The authors have previously shown that its detection in prostate cancer correlated with high-grade, large volume, and advanced stage tumors. This study examines the association between OA- 519 immunoreactivity in primary prostate cancer and disease progression. The authors used immunohistochemistry with an affinity-purified anti-OA-519 antibody and examined primary prostate cancers (stages A1 to D1) from 99 men with a mean follow-up of 4 years (range= 2 to 9.3). Survival analysis was used to evaluate differences in progression-free survival. OA-519 immunoreactivity was seen in 56 (57%) of the 99 primary prostate cancers examined. OA-519-positive cancers were more likely to progress than the OA- 519-negative cancers (P < .04). Univariate survival analysis showed that OA- 519 (FAS), histological grade (Gleason score), and clinical stage were significant predictors of disease progression. Multivariate analyses of all cases showed that only histological grade was significant. However, multivariate analysis of the 85 cancers with Gleason scores 2-7 (ie, low to intermediate grade) showed OA-519 (FAS) immunoreactivity to be the only statistically significant predictor of cancer progression (P<.02). Expression of the fatty acid synthase OA-519 by prostate cancers is potentially a clinically useful predictor of disease progression. It appears to be independent of histological grade (Gleason score), at least in cancers with low to intermediate grades. Further studies are needed to evaluate the role of fatty acid synthase in malignancy and the potential therapeutic implications of enzyme blockers.
915

The Microvascular Bed of Fatty Bone Marrow in the Adult Beagle

Miller, S. C., Jee, W. S.S. 01 January 1980 (has links)
The structure and ultrastructure of the microvascular bed of fatty bone marrow and the relationships of this vascular bed to endosteal bone surfaces was studied in adult beagles. The vascular volume of fatty bone marrow, as demonstrated by India ink-gelatin perfusion, appears less than the vascular volume of red bone marrow. The capillaries in fatty bone marrow are found between the large fat cells in a loose reticular connective tissue and have a continuous endothelial lining and basal lamina. Capillaries are frequently found adjacent to bone surfaces in these fatty marrow sites, yet are separated from these surfaces by very thin bone-lining cells. The nuclei of bone-lining cells are often found near these capillaries. The association of bone-lining cells to the microvasculature suggests that these cells may play a role in partitioning the extracellular fluids from the bone.
916

Effects of Maternal Dietary Fats and Antioxidants on Growth Rate and Bone Development of Commercial Broilers

Taylor, Douglas Lumont Jr. 03 June 1998 (has links)
The effect of maternal dietary fats on growth rate and bone development of commercial broilers was examined. Three hundred fifty female chicks were winged banded, weighed and equally divided among six starter pens (1.52 X 3.66m) with litter floors. At 20 wk of age, each pen was fed a basal laying diet supplemented with either 3% chicken fat (CF), soybean oil (SBO) or menhaden oil (MO). Each diet was provided with or without the antioxidant ethoxyquin, producing a total of six dietary treatments. Addition of fats [soybean (SBO), menhaden oil (MO), chicken fat (CF), soybean + antioxidant (SA), menhaden + antioxidant (MA), and chicken + antioxidant (CA)] to the maternal diet altered the tissue and yolk composition of hens to reflect the dietary source. Response variables measured were body weight, tibia weight and length, and breaking strength (stress, force, energy, bone wall, and diameter). Chick tissue from hens fed a MO and MA diet exhibited greater (P<0.01) amounts of DPA (22:5n3), DHA (22:6n3) and total n-3 fatty acids than the remaining dietary treatments. Tissues from chicks fed a SBO and SA diet displayed larger levels of 18:2n6 and total n-6 fatty acids when compared to all other treatments. Male and female chicks from the menhaden type diets (MO and MA) were lighter (P<0.01) during grow out period than from soybean (SBO and SA) and chicken (CF and CA) type diets. Chicks tibiae diameter from CF maternal diet tended to be larger than the MO maternal diet, with significance being noted at d 14 (P<0.01) and 28 (P<0.01). Increases were observed in shear force and stress required to break chick tibia from SBO maternal diet compared to those from the CF and MO maternal diets. The SBO maternal diet stimulates growth rate and bone development and strength of the progeny. (Key words: chickens, bone development, breaking strength, growth rate, fatty acids) / Master of Science
917

Biomarker of Long-Chain N-3 Fatty Acid Intake and Breast Cancer: Accumulative Evidence From an Updated Meta-Analysis of Epidemiological Studies

Yang, Bo, Ren, Xiao L., Wang, Zhi Y., Wang, Liang, Zhao, Feng, Guo, Xiao J., Li, Duo 28 October 2019 (has links)
Objective: We aimed to summarize the up-to-date epidemiology evidence on biomarkers of long-chain (LC) n-3 fatty acid (FA) intake in relation to breast cancer (BC). Methods: Epidemiology studies determining FA levels in biospecimen (circulating blood or adipose tissue (AT)) were identified from PubMed, EMBASE, and Cochrane Library databases until March 2018. Multivariate-adjusted risk ratios (RRs) with 95% confidence intervals (CIs) were pooled using a random-effect model. Difference in biospecimen proportions of LC n-3 FA between BC cases and non-cases were analyzed as a standardized mean difference (SMD). Results: Thirteen cohort and eleven case-control studies were eligible for the present meta-analysis. The estimated SMD was -0.14 (95% CI: -0.27, -0.11) for LC n-3 FA and -0.27 (95% CI: -0.42, -0.11) for LC n-3/n-6 FA ratio. When comparing the top tertiles with the bottom baseline levels, circulating LC n-3 FA was significantly associated with a lower risk of BC (RR: 0.84, 95% CI: 0.74, 0.96), but not AT (RR: 1.02, 95% CI: 0.70, 1.48). Significant inverse dose-response associations were observed for each 1% increment of circulating 20:5n-3 and 22:6n-3. Conclusion: This meta-analysis highlights that circulating LC n-3 FA as a biomarker of intake may be an independent predictive factor for BC, especially 20:5n-3 and 22:6n-3.
918

Nonalcoholic Fatty Liver Disease and Albuminuria: A Systematic Review and Meta-Analysis

Wijarnpreecha, Karn, Thongprayoon, Charat, Boonpheng, Boonphiphop, Panjawatanan, Panadeekarn, Sharma, Konika, Ungprasert, Patompong, Pungpapong, Surakit, Cheungpasitporn, Wisit 01 September 2018 (has links)
Background/objectives The relationship between nonalcoholic fatty liver disease (NAFLD) and albuminuria has been shown in many epidemiologic studies, although the results were inconsistent. This meta-analysis was conducted to summarize all available data and to estimate the risk of albuminuria among patients with NAFLD. Methods Comprehensive literature review was conducted utilizing Medline and Embase database through January 2018 to identify studies that compared the risk of albuminuria among patients with NAFLD versus those without NAFLD. Effect estimates from each study were extracted and combined using the random-effect, generic inverse variance method of DerSimonian and Laird. Results Nineteen studies (17 cross-sectional studies and two cohort studies) with 24 804 participants fulfilled the eligibility criteria and were included in this meta-analysis. The risk of albuminuria among patients with NAFLD was significantly higher than those without NAFLD with the pooled odds ratio (OR) of 1.67 [95% confidence interval (CI): 1.32-2.11]. Subgroup analysis demonstrated the significantly increased risk of albuminuria among patients with NAFLD without diabetes with pooled OR of 2.25 (95% CI: 1.65-3.06). However, we found no significant association between albuminuria and NAFLD among diabetic patients [pooled OR 1.28 (95% CI: 0.94-1.75)]. Conclusion A significantly increased risk of albuminuria among patients with NAFLD was observed in this meta-analysis. Physicians should pay more attention to the early detection and subsequent treatment of individuals with microalbuminuria especially in patients with NAFLD.
919

Alcoholic Fatty Liver Is Enhanced in CYP2A5 Knockout Mice: The Role of the PPARα-FGF21 Axis

Chen, Xue, Ward, Stephen C., Cederbaum, Arthur I., Xiong, Huabao, Lu, Yongke 15 March 2017 (has links)
Background & aims Cytochrome P450 2A5 (CYP2A5) is induced by ethanol, and the ethanol induction of CYP2A5 is regulated by nuclear factor-erythroid 2-related factor 2 (NRF2). Cyp2a5 knockout (Cyp2a5−/−) mice develop more severe alcoholic fatty liver than Cyp2a5+/+ mice. Fibroblast growth factor 21 (FGF21), a PPARα-regulated liver hormone, is involved in hepatic lipid metabolism. Alcoholic and non-alcoholic fatty liver are enhanced in Pparα knockout (Pparα−/−) mice. This study investigates the relationship between the PPARα-FGF21 axis and the enhanced alcoholic fatty liver in Cyp2a5−/− mice. Methods Mice were fed the Lieber-Decarli ethanol diet to induce alcoholic fatty liver. Results More severe alcoholic fatty liver disease was developed in Cyp2a5−/− mice than in Cyp2a5+/+ mice. Basal FGF21 levels were higher in Cyp2a5−/− mice than in Cyp2a5+/+ mice, but ethanol did not further increase the elevated FGF21 levels in Cyp2a5−/− mice while FGF21 was induced by ethanol in Cyp2a5+/+ mice. Basal levels of serum FGF21 were lower in Pparα−/− mice than in Pparα+/+ mice; ethanol induced FGF21 in Pparα+/+ mice but not in Pparα−/− mice, whereas ethanol induced hypertriglyceridemia in Pparα−/− mice but not in Pparα+/+ mice. Administration of recombinant FGF21 normalized serum FGF21 and triglyceride in Pparα−/− mice. Alcoholic fatty liver was enhanced in liver-specific Fgf21 knockout mice. Pparα and Cyp2a5 double knockout (Pparα−/−/Cyp2a5−/−) mice developed more severe alcoholic fatty liver than Pparα+/+/Cyp2a5−/− mice. Conclusions These results suggest that CYP2A5 protects against the development of alcoholic fatty liver disease, and the PPARα-FGF21 axis contributes to the protective effects of CYP2A5 on alcoholic fatty liver disease.
920

Factors affecting the composition of long-chain fatty acids in the African buffalo (Syncerus caffer)

Steenkamp, Karen 07 December 2006 (has links)
Please read the abstract in the section 00front of this document / Dissertation (MSc Agric (Production Physiology))--University of Pretoria, 2000. / Animal and Wildlife Sciences / unrestricted

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