Composition and cross-sectional area of muscle fibre types in relation to daily gain and lean and fat content of carcass in Landrace and Yorkshire pigs

Selostus: Lihassolutyypin ja lihassolun poikkipinta-alan yhteys sian kasvuun ja ruhon koostumukseen maatiaisessa ja yorkshiressa

Effects of Dietary Fat Oxidation Products and Flavonols on Lipoprotein Oxidation

Various studies suggest that oxidative modifications of low density lipoprotein (LDL), and also other lipoproteins, have an important role in the development of atherosclerosis. In addition to the oxidation products formed endogenously, oxidised triacylglycerols (TAG) and oxysterols in the diet contribute to the oxidised lipoproteins found in circulation. However, studies on both the effect of oxidised dietary lipids on lipoprotein lipid oxidation and the reactions that modify oxidised fat after ingestion have been scarce. Studies on the effects of dietary antioxidants on the lipid oxidation in vivo and the risk of atherosclerosis have been inconclusive. More clinical trials are needed to test the importance of lipoprotein oxidation as a cardiovascular risk factor in humans. In the recent years, various methods have been optimised and applied to the analysis of lipid oxidation products in vivo, and information on the molecular structures of oxidised lipids in plasma, lipoproteins and atherosclerotic plaques has started to accumulate. However, specific structures of oxidised TAG molecules present in these tissues and lipoprotein fractions have not been investigated earlier. In the orginal research in this thesis, an approach based on highperformance liquid chromatographyelectrospray ionisationmass spectrometry (HPLCESIMS) and baseline diene conjugation (BDC) methods was used in order to investigate lipid oxidation level and oxidised TAG molecular structures in pig and human lipoproteins after dietary interventions. The approach was optimised with human LDL samples, which contained various oxidation products of TAG. LDL particles of hyperlipidaemic subjects contained an elevated amount of conjugated dienes. In the pig studies, several oxidised TAG structures with hydroxy, keto, epoxy or aldehydic groups were found in chylomicrons and VLDL after diets rich in sunflower seed oil. Also, the results showed that oxidised sunflower seed oil increased the oxidation of lipoprotein lipids and their TAG molecules. TAG hydroperoxides could be detected neither in the small intestinal mucosa of the pigs fed on the oxidised oil nor in their chylomicrons or VLDL.6 In the clinical studies, dietary flavonol aglycones extracted from sea buckthorn berries did not have an effect on lipoprotein lipid oxidation and other potential risk factors of atherosclerosis, but their absorption was demonstrated. Oil supplementation seemed to increase the bioavailability of the flavonols. Oxidised TAG molecules were detected in LDL particles of the subjects after both flavonol and control diets.

Regime Switching Models for Electricity Time Series that Capture Fat Tailed Distributions

In the power market, electricity prices play an important role at the economic level. The behavior of a price trend usually known as a structural break may change over time in terms of its mean value, its volatility, or it may change for a period of time before reverting back to its original behavior or switching to another style of behavior, and the latter is typically termed a regime shift or regime switch. Our task in this thesis is to develop an electricity price time series model that captures fat tailed distributions which can explain this behavior and analyze it for better understanding. For NordPool data used, the obtained Markov Regime-Switching model operates on two regimes: regular and non-regular. Three criteria have been considered price difference criterion, capacity/flow difference criterion and spikes in Finland criterion. The suitability of GARCH modeling to simulate multi-regime modeling is also studied.

Berry polyphenol absorption and the effect of northern berries on metabolism, ectopic fat accumulation, and associated diseases

The prevalence of obesity and type 2 diabetes has increased at an alarming rate in developed countries. It seems in the light of current knowledge that metabolic syndrome may not develop at all without NAFLD, and NAFLD is estimated to be as common as metabolic syndrome in western population (23 % occurrence). Fat in the liver is called ectopic fat, which is triacylglycerols within the cells of non-adipose tissue. Serum alanine aminotransferase (ALT) values correlate positively with liver fat proportions, and increased activity of ALT predicts type 2 diabetes independently from obesity. Berries, high in natural bioactive compounds, have indicated the potential to reduce the risk of obesity-related diseases. Ectopic fat induces common endocrine excretion of adipose tissue resulting in the overproduction of inflammatory markers, which further induce insulin resistance by multiple mechanisms. Insulin resistance inducing hyperinsulinemia and lipolysis in adipocytes increases the concentration of free fatty acids and consequently causes further fat accumulation in hepatocytes. Polyphenolic fractions of berries have been shown to reverse inflammatory reaction cascades in in vitro and animal studies, and moreover to decrease ectopic fat accumulation. The aim of this thesis was to explore the role of northern berries in obesity-related diseases. The absorption and metabolism of selected berry polyphenols, flavonol glycosides and anthocyanins, was investigated in humans, and metabolites of the studied compounds were identified in plasma and urine samples (I, II). Further, the effects of berries on the risk factors of metabolic syndrome were studied in clinical intervention trials (III, IV), and the different fractions of sea buckthorn berry were tested for their ability to reduce postprandial glycemia and insulinemia after high-glucose meal in a postprandial study with humans (V). The marked impact of mixed berries on plasma ALT values (III), as well as indications of the positive effects of sea buckthorn, its fractions and bilberry on omental adiposity and adhesion molecules (IV) were observed. In study V, sea buckthorn and its polyphenol fractions had a promising effect on potprandial metabolism after high-glucose meal. In the literature review, the possible mechanisms behind the observed effects have been discussed with a special emphasis on ectopic fat accumulation. The literature review indicated that especially tannins and flavonoids have shown potential in suppressing diverse reaction cascades related to systemic inflammation, ectopic fat accumulation and insulin resistance development.

FAT-luokkien määritys hitsatuille levyliitoksille käyttämällä lineaarisen murtumismekaniikan särönkasvun simulointia

Työssä tutkittiin hitsattujen levyliitosten väsymiskestävyyden mitoitusarvoja. Hitsien väsymiskestävyyden mitoitusarvot määritettiin lineaarista murtumismekaniikkaa soveltavalla 2D FEM-laskentaohjelmalla. Murtumismekaanisen laskennan tuloksista määriteltiin, eri liitosgeometrioiden ja kuormitustyyppien mukaisia, nimellisen jännityksen väsymismitoitusmenetelmää vastaavia FAT-luokkia, joissa on huomioitu rakenteellinen jännitys hitsiä vastaan kohtisuorassa suunnassa. Tutkittujen liitosten geometriat olivat pääsääntöisesti poikkeavia mitoitusstandardien ja ohjeiden sisältämistä taulukkotapauksista. Laskennassa otettiin huomioon hitsien liittymiskulma perusaineeseen, rajaviivan pyöristykset ja vajaa hitsautumissyvyys. Kuormitustyyppien vaihtelua tutkittiin rakenteellisen jännityksen taivutusosuuden muutoksilla ja kuormaa kantavien X-liitosten risteävien kuormituksien suhteellisilla suuruuksilla. Väsymiskestävyydet määritettiin kuormituskohtaisille kalvo- ja taivutusjännityksille sekä näiden jännitysjakaumien keskiarvoille. Työssä saatuja FAT-luokkia voidaan hyödyntää vastaavien geometrioiden ja kuormitusten yhteydessä, sekä interpoloimalla myös tuloksien väliarvoissa. Työssä käytetyillä menetelmillä voidaan parantaa nimellisen jännityksen mitoitusmenetelmän tarkkuutta ja laajentaa sitä koskemaan myös taulukkotapausten ulkopuolisia liitoksia. Työn tuloksissa on esitetty FAT-luokkia T-, X- ja päittäisliitoksille ja näiden eri kuormitusyhdistelmille.

Phenomena and mechanisms in purification of animal fat

Työn tarkoitus oli tutkia eläinrasvan puhdistusta biodieselin valmistusta varten. Eläinrasvaa syntyy elintarviketeollisuuden sivutuotteena ja sitä saadaan myös myymättä jääneistä elintarvikkeista. Rasva sisältää epäpuhtauksia, jotka on poistettava ennen biodieselprosessia. Tässä työssä tutkittavat epäpuhtaudet ovat typpi, fosfori, rauta, natrium, kalsium ja magnesium. Puhdistusmenetelminä käytettiin saostamista sitruunahapolla sekä adsorbointia kahdella eri adsorbentilla. Tavoitteena oli selvittää riittävä määrä happoa ja adsorbenttia sekä tutkia puhdistuksen mekanismia. Lisäksi tarkasteltiin lämpötilan vaikutusta adsorption aikana.