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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.
31

Antiarrhythmic mechanisms of omega-3 polyunsaturated fatty acids in rat ventricular cardiomyocytes / Wayne R. Leifert.

Leifert, Wayne R. January 2001 (has links)
Includes bibliographical references (leaves 237-257). / xx, 257 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Investigates the mechanisms underlying the antiarrhythmic effects of omega-3 polyunsaturated fatty acids using adult rat ventricular cardiac myocytes. / Thesis (Ph.D.)--Adelaide University, Dept. of Physiology, 2001
32

Studies on cell injury induced by hypoxia-reoxygenation and oxidized low density lipoprotein : with special reference to the protectiove effect of mixed tocopherols, omega-3 fatty acids and transforming growth factor-beta1 /

Chen, Hongjiang, January 2003 (has links)
Diss. (sammanfattning) Uppsala : Univ., 2003. / Härtill 5 uppsatser.
33

Marine oils : stabilization, structural characterization and omega-3 fatty acid concentration /

Wanasundara, Udaya Nayanakantha, January 1996 (has links)
Thesis (Ph.D.)--Memorial University of Newfoundland, 1997. / Restricted until December 2000. Bibliography: leaves [252]-282.
34

ProduÃÃo de biodiesel assistida por ultra-som / Production of biodiesel assisted by ultrasound

Francisco Francielle Pinheiro dos Santos 26 February 2009 (has links)
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Este trabalho apresenta a utilizaÃÃo de uma nova tecnologia de produÃÃo de biodiesel utilizando ultra-som, em substituiÃÃo a tÃcnica tradicional que emprega aquecimento e agitaÃÃo vigorosa da mistura reacional. O processo de produÃÃo de biodiesel utilizando ultra-som foi aplicado aos processos de esterificaÃÃo de Ãcidos graxos de origem vegetal e animal e de transesterificaÃÃo de Ãleo vegetal. Ãcidos graxos de Ãleo de peixe e de Ãleo de fritura usado (Ãleo de soja), produzidos atravÃs da reaÃÃo de saponificaÃÃo seguida de hidrÃlise Ãcida, foram utilizados nos estudos de esterificaÃÃo. A reaÃÃo de esterificaÃÃo foi realizada em reator batelada submetida a ondas ultrasÃnicas, e a reaÃÃo ocorreu pela reaÃÃo do Ãcido graxo com metanol usando Ãcido sulfÃrico como catalisador. Nos estudos de esterificaÃÃo foram estudados, via planejamento experimental, as principais variÃveis do processo: razÃo molar metanol:Ãcido graxo (razÃo molar entre 3 e 9), concentraÃÃo de catalisador (entre 0,5 a 3,5% em massa) e temperatura (entre 30 e 90ÂC). Ãleo de soja foi utilizado no estudo de transesterificaÃÃo. A reaÃÃo de transesterificaÃÃo tambÃm foi realizada em reator batelada submetida a ondas ultrasÃnicas, e a reaÃÃo ocorreu pela reaÃÃo do Ãleo com metanol usando hidrÃxido de potÃssio como catalisador. Nos estudos de transesterificaÃÃo foram estudados a influÃncia da razÃo molar metanol:Ãleo (razÃo molar entre 3 e 9) e da concentraÃÃo de catalisador (entre 0,2 a 0,6% em massa) no processo. Para efeito comparativo, a reaÃÃo auxiliada por ultra-som foi comparada ao processo convencional (agitaÃÃo vigorosa), mostrando que o processo utilizando ultra-som resultou em uma conversÃo em biodiesel superior ao processo convencional. A produÃÃo de biodiesel usando Ãcido graxo de Ãleo de peixe resultou em uma conversÃo de 99,9% de Ãcido graxo em biodiesel e a condiÃÃo Ãtima foi obtida com uma razÃo molar metanol:Ãcido graxo de 7, usando 4,1% de catalisador. Usando Ãcido graxo de Ãleo de fritura resultou em uma conversÃo de 99,0% de Ãcido graxo em biodiesel e a condiÃÃo Ãtima foi obtida com uma razÃo molar metanol:Ãcido graxo de 11, usando 1,25% de catalisador e temperatura de 60ÂC. Para a reaÃÃo de transesterificaÃÃo, a conversÃo obtida foi de 98% de Ãleo em biodiesel e foi obtida aplicando uma razÃo molar metanol:Ãleo de 9, usando 0,2% de catalisador. Os resultados mostraram que o processo de produÃÃo de biodiesel utilizando ultra-som à uma tecnologia promissora, obtendo-se conversÃes maiores do que o processo convencional. O tempo necessÃrio de processamento à menor do que no processo convencional e para o processo de esterificaÃÃo, o tempo total (produÃÃo do Ãcido graxo e esterificaÃÃo) à 75% menor. O processo mostrou necessitar de uma menor quantidade de catalisador, minimizando problemas reacionais, tais como a formaÃÃo de sabÃo na reaÃÃo de transesterificaÃÃo / This work presents the use of a new technology for biodiesel production applying ultrasound, instead of using the conventional method that requires heating and vigorous mixing. The process for biodiesel production applying ultrasound was studied with the esterification reaction of fatty acid of vegetal and animal origin and with the transesterification reaction of vegetal oil. Fatty acids from fish oil and from waste oil (soybean oil), produced by the saponification reaction followed by acid hydrolysis, were used in the esterification studies. The esterification reaction was carried out in a batch reactor subjected to ultrasound, reacting the fatty acid with methanol using sulfuric acid as catalyst. In the esterification studies, the main parameters that affect the reaction were studied: molar ratio of methanol and fatty acid (from 3 to 9), catalyst concentration (between 0.5 to 3.5%) and temperature (between 30 and 90ÂC). Soybean oil was used in the transesterification reactions. The transesterification reaction was also carried out in a batch reactor subjected to ultrasonic waves, reacting the oil with methanol using potassium hydroxide as catalyst. In the transesterification reaction, the parameters molar ratio of methanol and oil (between 3 and 9) and catalyst concentration (from 0.2 and 0.6%) were studied. To compare the ultrasound process with the onventional process, the reactions were carried out with both processes. The results showed that the ultrasound process was superior to the conventional process in terms of conversion into biodiesel. The production of biodiesel using fatty acid of fish oil resulted in a conversion of 99.9% of fatty acid into biodiesel and the optimal condition was found applying a molar ratio of methanol to fatty acid of 7, using 4.1% of catalyst. Using the waste oil fatty acid, the highest conversion obtained was at 99.0% and was obtained at a molar ratio of methanol to fatty acid of 11, using 1.25% of catalyst and 60ÂC. For the transesterification reaction, the conversion of soybean oil into biodiesel was 98% and was obtained applying a molar ratio of 9 and 0.2% of catalyst. The results showed that the process for biodiesel production using ultrasound is a promising technology that is able to obtain higher conversions compared to the conventional process. The processing time is lower than of the conventional process and for the esterification process, the total processing time (production of the fatty acid and esterification) is 75% lower. The process also required less catalyst, reducing reacting problems such as soap formation during transesterification
35

Effects of dietary fish oil supplementation on the skeletal muscle blood flow response to submaximal treadmill exercise

Hammel, Lauren E. January 1900 (has links)
Master of Science / Department of Kinesiology / Timothy I. Musch / Dietary supplementation with omega-3 polyunsaturated fatty acids (PUFAs) containing docosahexaenoic (DHA) and eicosapentaenoic acid (EPA) has been demonstrated to produce advantageous effects on vascular function. Specifically, PUFA supplementation has resulted in enhanced brachial artery blood flow (Q), dilation, and vascular conductance (VC) during rhythmic handgrip exercise. The effects of fish oils (FO) on skeletal muscle blood flow (Qm) during dynamic whole body exercise, however, remain unknown. PURPOSE: To test our hypothesis that 6 weeks of dietary FO supplementation with DHA and EPA enhances regional Qm and VC to the hindlimb musculature during submaximal treadmill exercise. METHODS: Following 6 weeks of dietary supplementation with safflower oil (SO) (control; n = 9) or FO (n = 8), heart rate (HR), mean arterial pressure (MAP), and Q[subscript]m to the hindlimb were measured at rest and during submaximal treadmill exercise (20 m/min, 10%, ~65% VO[subscript]2max) via radiolabeled microspheres in adult male Sprague-Dawley rats. RESULTS: HR and MAP were not different between SO and FO at rest or exercise (P<0.05). Q[subscript]m and VC were not different between SO and FO at rest. During exercise, FO exhibited greater Q[subscript]m in 8 of the 28 muscle parts measured as well as greater VC in 11 of the 28 muscle parts measured. Additionally, FO exhibited greater (Q)[subscript] m (158[plus or minus]9) and VC (1.156[plus or minus]0.066) to the total hindlimb musculature than SO (128[plus or minus]10 ml/min/100g, 0.918[plus or minus]0.077 ml/min/100g/mmHg) (P<0.05). CONCLUSION: These results demonstrate that 6 weeks of dietary FO supplementation with DHA and EPA results in enhanced Q[subscript]m and VC to the hindlimb during submaximal exercise. Thus, supplementation with DHA and EPA may have therapeutic effects on oxygen delivery and vascular function in patients with impaired vascular function and exercise tolerance (i.e., congestive heart failure, diabetes).
36

Exercício em esteira e suplementação com óleo de peixe em ratos no início da vida: efeitos sobre ansiedade, memória e excitabilidade cerebral

MELO, Janatar Stella Vasconcelos de 03 March 2016 (has links)
Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2017-07-13T13:30:25Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Dissertação_JanatarStellaVaconcelosdeMelo_2016.pdf: 1719619 bytes, checksum: 6315f0db6eb0f7ba21328cc670638617 (MD5) / Made available in DSpace on 2017-07-13T13:30:25Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Dissertação_JanatarStellaVaconcelosdeMelo_2016.pdf: 1719619 bytes, checksum: 6315f0db6eb0f7ba21328cc670638617 (MD5) Previous issue date: 2016-03-03 / CAPES / As fases iniciais da vida representam um período crítico no desenvolvimento do sistema nervoso. O objetivo desse estudo foi avaliar efeitos da associação entre exercício físico em esteira e suplementação com óleo de peixe em ratosno início da vida, sobre ansiedade, memória e excitabilidade cerebral. Ratos Wistar foram divididos em: Óleo de Peixe ou Veículo e subdivididos em Exercitados ou Sedentários. O período de treinamento ocorreu do 15º ao 45º dias de vida. A partir dos 46 dias de vida, foi realizada avaliação dos efeitos dessa associação sobre peso corporal, murinometria, respostas comportamentais relacionadas à ansiedade, memória e eletrofisiologia cortical. Os resultados demonstram que não houve alteração nos dados murinométricos. No teste de labirinto em cruz elevado, os animais exercitados apresentaram comportamento menos ansioso a julgar pelo maior número de entradas nos braços abertos. Além disso, animais suplementados e/ou exercitados apresentaram memória preservada para reconhecimento da identidade do objeto. Por outro lado, a análise intragrupo demonstrou prejuízo dependente do tratamento, quando os animais foram submetidos ao teste de reconhecimento quanto à localização do objeto. Com relação à análise intergrupo, a suplementação e o exercício aumentaram o índice de discriminação para o objeto estacionário. Sobre a eletrofisiologia cerebral, houve potencialização da suplementação sobre o exercício na redução da velocidade de propagação da depressão alastrante cortical. Neste contexto, os resultados indicam que é necessária cautela no uso da associação dessas estratégias referentes à modulação comportamental ou neural em períodos críticos de desenvolvimento do sistema nervoso. / The early stages of life represent a critical period in the development of the nervous system. The aim of this study was to evaluate how the association between treadmill exercise and supplementation with fish oil in rats during lactation affect anxiety, memory and brain excitability. Wistar rats performed two experimental groups as Fish Oil or vehicle, and then divided into exercised or sedentary. The training period was from the 15th to 45th days of life. From the 46 days of life, the effects of this combination on body weight, murimetric parameters, behavioral assessment, and cortical electrophysiology were evaluated. The results demonstrate that there was no change in murinometric data. In the elevated plus maze, exercised animals were less anxious as judged by the largest number of entries into the open arms as compared to the respective controls. Furthermore, supplemented and / or trained animals showed preserved memory to recognize the identity of the object. On the other hand, the intra-group analysis showed treatment-dependent impairment when the animals were subjected to the recognition test on the object location. The inter-group analysis supplementation and exercise increased the discrimination index for the stationary object. In addition, supplementation with fish oil enhanced the effect of exercise on brain excitability by reducing the velocity of propagation of cortical spreading depression. Therefore, the present data indicate that caution is required in use of the association of these strategies concerning behavioral or neural modulation.
37

The Effect of Omega-3 Fatty Acids on Airway Inflammation, Hyperpnea-Induced Bronchoconstriction, and Airway Smooth Muscle Contractility in Asthma

Head, Sally K. 16 March 2012 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Asthma, a chronic inflammatory disease of the airways, affects nearly 25 million Americans. The vast majority of these patients suffer from exercise-induced bronchoconstriction (EIB), a complication of asthma. Although traditionally treated pharmacologically, nutritional strategies provide a promising alternative for managing EIB as the prevalence of asthma may be due in part to changes in diet. Our objective was to determine the effects of novel nutritional strategies on hyperpnea-induced bronchoconstriction (HIB) in asthmatic individuals. HIB uses rapid breathing to identify EIB in a research or clinical setting. Fish oil, a combination of the omega-3 fatty acids eicosapentaenoic acid (EPA) and docsahexaenoic acid (DHA), has been shown to be effective in suppressing EIB. However, its use in combination with other nutritional supplements, the optimal fish oil formula, and its effect on smooth muscle contractility have not been fully explored. An in vivo study (study 1) was conducted in individuals with both asthma and HIB to determine whether a combination of fish oil and vitamin C was more effective than either one alone in alleviating HIB. Pulmonary function was significantly improved with both fish oil and the combination treatment but not with vitamin C alone. In study 2, individuals with both asthma and HIB were supplemented with DHA alone since the optimal formula for fish oil has yet to be ascertained; previous in vitro studies have suggested DHA may be the more potent omega-3 fatty acid in fish oil. However, no significant changes in pulmonary function or airway inflammation were seen with DHA supplementation. For study 3, canine airway smooth muscle tissue was treated with fish oil to determine the in vitro effect of fish oil on smooth muscle contractility. Acute treatment with fish oil relaxed smooth muscle strips that had been contracted with 5-hydroxytryptamine. These minor relaxations in smooth muscle tension with fish oil may represent significant changes at the level of the smaller airways. These studies have confirmed that fish oil represents a viable treatment modality for asthmatic individuals with EIB and suggest that fish oil may influence airway smooth muscle contractility.
38

The effect of exercise and fish oil supplements on the blood lipid levels of the hamster

Kennel, Phyllis D. 29 November 2012 (has links)
The effect of aerobic exercise and fish oil supplements on plasma lipid parameters was investigated in the hamster. The hamsters were fed a basal hypercholesterolemic purified diet (0.1% cholesterol, 15% fat) to elicit an elevated lipid response. Fifty-six hypercholesterolemic hamsters were divided into four groups: control, swimming (trained up to one hour every other day), daily fish oil supplementation (.35g/kg/day omega-3), and a swimming/fish oil combination. The effect of these treatments on plasma TC, TG and pooled samples of plasma HDL-C, HDL2â C, LDL-C and VLDL-C was studied over 12 weeks. All hamsters had a significant increase in body weight. Feed intakes increased at 6 weeks and then declined over the second 6 weeks, but remained above the beginning levels. / Master of Science
39

Enriquecimento do ovo: utilização de óleos de peixes e alga marinha como fontes de ácidos graxos poliinsaturados ômega-3 em rações de galinhas / Egg\'s enrichment: utilization of fish oils and marine algae as sources of omega-3 polyunsaturated fatty acids in hens\' diet.

Piber Neto, Eduardo 24 February 2006 (has links)
Foram utilizadas 168 galinhas poedeiras Hisex White em delineamento experimental inteiramente casualizado, com duração de cinco semanas. As aves foram distribuídas em sete tratamentos com três repetições cada, com o objetivo de verificar a influência da suplementação de três fontes marinhas de PUFAs n-3 - óleos de salmão (SA) e de atum e sardinha (A/S) e mistura de algas marinhas (AL), bem como sua combinações (SA+A/S, AL+SA, AL+A/S) - em relação ao grupo controle alimentado com ração basal de milho e soja (CON), sobre a qualidade do ovo e a composição lipídica da gema. A qualidade externa e interna do ovo não foi alterada significativamente pela adição de fontes de PUFAs n-3 na dieta das aves. A relação entre os lípides saturados : monoinsturados : poliinsaturados da gema (3,5 : 4,5 : 2,0) manteve-se constante com a adição dos suplementos de PUFAs n-3 na ração. Os óleos de salmão (SA) e de atum e sardinha (A/S) revelaram-se mais efetivos no enriquecimento da gema do ovo em PUFAs n-3, em especial o DHA. A relação PUFAs n-6/ PUFAs n-3 sofreu redução significativa com a adição das fontes marinhas de ômega-3 à dieta das galinhas. O EPA, embora em teores mais baixos que o DHA na gema do ovo, apresentou incremento significativo com o uso dos óleos de peixes (SA e A/S) adicionado à dieta em relação ao CON. O consumo de dois ovos enriquecidos com DHA do presente estudo, por dia, provavelmente atenderia os requerimentos diários deste PUFA n-3 para o ser humano / To investigate the influence of three PUFAs n-3 marine sources - salmon oil (SA), tuna and sardine oil (A/S), marine algae (AL) and combinations (SA+A/S, AL+SA, AL+A/S) - on egg quality and egg lipid composition, compared to a corn/soy control group (CON), 168 Hisex White laying hens were assigned into seven treatments with three repetitions in a randomized design during a experimental period of five weeks. The external and internal egg quality were not significantly affected by the addition of PUFAs n-3 marine sources into the hen diets. The saturated : monounsaturated : polyunsaturated ratio (3.5:4.5:2.0) remained constant by the supplementation of the marine sources into the diets. The salmon oil and the tuna and sardine oil showed the best results of PUFAs n-3 egg yolk enrichment, mainly the DHA. The PUFAs n-6/PUFAs n-3 ratio was significantly reduced by the inclusion of PUFAs n-3 sources into the hen diets. The EPA, although with lower levels than DHA into the egg yolk, showed a significant increase by the use of salmon oil and tuna and sardine oil added to the diet as compared to the control group (CON). The consumption of two DHA enriched eggs from this study per day probably would reach the daily requirements of this PUFA n-3 for the human been
40

Effects of dietary fish oil and fibre on contractility of gut smooth muscle.

Patten, Glen Stephen January 2008 (has links)
From animal experimentation, and studies using in vitro models, there was evidence in the literature to suggest that dietary fibre may influence contractility and motility of the gastrointestinal tract and long chain (LC) n-3 polyunsaturated fatty acids (PUFAs) from marine sources may influence contractility of smooth muscle cells in blood vessels. The hypothesis of this thesis was that dietary fish oil and/or fibre influence the contractility of isolated intact sections of gut smooth muscle tissue from small animal models. Methodology was established to measure in vitro contractility of intact pieces of guinea pig ileum with the serosal side isolated from the lumen. It was demonstrated that four amino acid peptides from κ-casein (casoxins) applied to the lumen overcame morphine-induced inhibition of contraction. Using this established technology, the guinea pig was used to investigate the effects of dietary fibre and fish oil supplementation on gut in vitro contractility. In separate experiments, changes in sensitivity to electrically-driven and 8-iso-prostanglandin (PG)E₂-induced contractility were demonstrated for dietary fibre and fish oil. A modified, isolated gut super-perfusion system was then established for the rat to validate these findings. It was subsequently shown that LC n-3 PUFA from dietary fish oil significantly increased maximal contraction in response to the G-protein coupled receptor modulators, acetylcholine and the eicosanoids PGE₂, PGF₂α, 8-iso-PGE₂ and U-46619 in ileum but not colon, without changes in sensitivity (EC₅₀), when n-3 PUFA as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) had been incorporated to a similar degree into the gut total phospholipid membrane pool. It was further established that the spontaneously hypertensive rat (SHR) had a depressed prostanoid (PGE₂and PGF₂α) response in the gut that could be restored by dietary fish oil supplementation (5% w/w of total diet) in the ileum but not the colon. Importantly, the muscarinic response in the colon of the SHR was increased by fish oil supplementation with DHA likely to be the active agent. Dietary fish oil dose experiments deduced differential increases in response occurred at fish oil concentrations of 1% for muscarinic and 2.5% (w/w) for prostanoid stimulators of the ileum with no difference in receptor-independent KCl-induced depolarization-driven contractility. Studies combining high amylose resistant starch (HAMS, 10% w/w) and fish oil (10% w/w) fed to young rats demonstrated a low prostanoid response that was enhanced by dietary fish oil but not resistant starch. There was however, an interactive effect of the HAMS and fish oil noted for the muscarinic-mimetic, carbachol. Generally, resistant starch increased the large bowel short chain fatty acid pool with a subsequent lower pH. Binding studies determined that while the total muscarinic receptor binding properties of an isolated ileal membrane fraction were not affected in mature rats by dietary fish oil, young rats had a different order of muscarinic receptor subtype response with a rank order potency of M₃ > M₁ > M₂ compared to mature animals of M₃ > M₂ > M₁ with fish oil altering the sensitivity of the M₁ receptor subtype in isolated carbachol-precontracted ileal tissue. In conclusion, experiments using the guinea pig and rat gut models demonstrated that dietary fish oil supplementation, and to a lesser degree fibre, increased receptor-driven contractility in normal and compromised SHR ileum and colon. Further, changes in responsiveness were demonstrated in the developing rat gut prostanoid and muscarinic receptor populations that could be altered by dietary fish oil. Preliminary evidence suggested that fish oil as DHA may alter receptor-driven gut contractility by mechanisms involving smooth muscle calcium modulation. Defining the role that dietary fibre and fish oil, and other nutrients, play in normal and diseased states of bowel health such as inflammatory bowel disease (IBD), where contractility is compromised, are among the ongoing challenges. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1316907 / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2008

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