Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Monocyte recruitment promotes the accumulation of myeloid foam cells in early atherosclerotic plaques. However, initial foam cells form prior to increased monocyte recruitment in hypercholesterolemic Ldlr-/- mice. These initial foam cells are derived from myeloid cells residing in the normal intima, and express integrin alphaX (CD11c). The goal of this thesis was to assess the role of initial foam cells in atherogenesis. The approach was to delete these cells by diphtheria toxin-induced apoptosis in Ldlr-/- bone marrow chimeras. Depletion of CD11c+ leukocytes resulted in significant reductions of intimal lipid accumulation, monocyte recruitment, intimal chemokine expression, but not endothelial cell adhesion molecule expression, at 10 and 21 days of hypercholesterolemia. These data suggest that lipid uptake by resident intimal CD11c-expressing myeloid cells during the earliest stages of atherosclerosis promotes chemokine production that is required for increased monocyte recruitment.

Monocyte recruitment promotes the accumulation of myeloid foam cells in early atherosclerotic plaques. However, initial foam cells form prior to increased monocyte recruitment in hypercholesterolemic Ldlr-/- mice. These initial foam cells are derived from myeloid cells residing in the normal intima, and express integrin alphaX (CD11c). The goal of this thesis was to assess the role of initial foam cells in atherogenesis. The approach was to delete these cells by diphtheria toxin-induced apoptosis in Ldlr-/- bone marrow chimeras. Depletion of CD11c+ leukocytes resulted in significant reductions of intimal lipid accumulation, monocyte recruitment, intimal chemokine expression, but not endothelial cell adhesion molecule expression, at 10 and 21 days of hypercholesterolemia. These data suggest that lipid uptake by resident intimal CD11c-expressing myeloid cells during the earliest stages of atherosclerosis promotes chemokine production that is required for increased monocyte recruitment.

The purpose of this study is to examine economic growth impact on financial sector development in the Baltic States by investigating interrelation between indicators of these two economic areas. Research is based on scientific literature and empirical analysis. Statistical data is collected mostly from World Bank database in the period between 1994-2009. Indicators like liquid liabilities to GDP and private credit to GDP ratio are used to measure the financial sector size and activity. Economic growth is analyzed throughout total production and factors which are suggested by three economic growth theories. Analysis of GDP is made by expenditure approach. Statistical data showed positive financial sector development in Baltic States during the research period. Estonia had highest developed financial sector, then followed Latvia and Lithuania. The main reason for strongest financial performance in Estonia can be explained by highest export and import activity, financial capital accumulation and lowest real interest rates, unemployment and population. Financial sector development in Latvia was supported by high education expenditure and capital formation in the private sector. Lowest performance of financial activity in Lithuania can be justified by greatest unemployment, population and lowest financial capital attraction. This work confirms Patrick's (1966) demand-following hypothesis which states that growing economy leads to increasing demand of financial services and so... [to full text] / Šių studijų tikslas yra ištirti ekonomikos augimo įtaką finansinio sektoriaus plėtrai Baltijos šalyse, nagrinėjant tarpusavio ryšį tarp šių dviejų ekonominiu sričių vystymosi rodiklių. Tyrimas remiasi moksline literatūra ir empirine analize. Statistiniai duomenys yra surinkti daugiausiai iš Pasaulio Banko duomenų bazės 1994-2009 metų laikotarpyje. Indikatoriai kaip likvidţių įsipareigojimų santykis su BVP ir privačių kreditų santykis su BVP yra naudojami matuojant finansinio sektoriaus dydį ir aktyvumą. Ekonomikos augimas analizuojamas per bendrą produkciją ir indikatorius, kurie buvo pasiūlyti trijų ekonomikos augimo teorijų. BVP analizuojamas išlaidų metodu. Statistiniai duomenys parodė pozityvų finansinio sektoriaus vystymąsi Baltijos šalyse tiriamajame laikotarpyje. Estija turėjo labiausiai išvystytą finansinį sektorių, po jos sekė Latvija ir galiausiai Lietuva. Stipri finansinė padėtis Estijoje gali būti paaiškinama dėl aukšto eksporto ir importo aktyvumo, finansinio kapitalo akumuliacijos ir ţemos palūkanų normos, ţemo nedarbo ir populiacijos. Finansinio sektoriaus plėtra Latvijoje buvo paremta didelėmis švietimo išlaidomis ir kapitalo formavimu privačiame sektoriuje. Silpnesnį finansinį sektorių Lietuvoje greičiausiai sąlygojo didţiausias nedarbas, populiacija, ir maţiausias finansinio kapitalo pritraukimas. Šis darbas patvirtina Patricko (1966) paklausos-sekimo hipotezę, kuri teigia, kad ekonomikos augimas veda prie didėjančios finansinių paslaugų paklausos ir taip... [toliau žr. visą tekstą]

Suspensions of pancreatic islet cells from ob/ob-mice were incubated with Trypan Blue. Microscope photometry showed that apparently viable cells excluded the dye completely, whereas the nuclei of non-viable cells accumulated Trypan Blue by a saturable process. Alloxan rapidly increased the permeability of the plasma membrane in mouse 3-cells; the exclusion of Trypan Blue is a valid and useful measure of islet cell viability following alloxan exposure. The diabetogenic action of alloxan may be mediated by hydroxyl radicals. In several biological systems hydroxyl radicals are formed by an iron-catalyzed reaction between superoxide anion radicals and hydrogen peroxide. To test whether this applies to alloxan diabetogenicity, the effects of superoxide dismutase, catalase, scavengers of hydroxyl radicals, and metal ion chelators were tested (a) in a cell-free radical-generating system and (b) on islets and islet-cells exposed to alloxan In vitro. The effect of longtime-circulating superoxide dismutase injected prior to alloxan was tested on mice in vivo. Luminol chemiluminescence was used to monitor alloxan-dependent radical production. Accumulation of 8^Rb+ and exclusion of Trypan Blue were used as cell viability criteria in isolated mouse islets and islet-cells. Blood glucose was determined to monitor the development of diabetes in living animals. Superoxide dismutase, catalase, scavengers of hydroxyl radicals, and metal ion chelators inhibited the alloxan-dependent chemiluminescence and decreased the toxic effects on Rb+ accumulation or Trypan Blue exclusion in islets and islet-cells. Superoxide dismutase, linked to polyethylene glycol and injected 12 hours before alloxan, largely prevented the development of alloxan diabetes. Alloxan toxicity _in vitro and in vivo seems to depend on the formation of superoxide radicals and hydrogen peroxide which in turn form the noxious hydroxyl radical via an iron-catalyzed Haber-Weiss reaction. As free radicals and hydrogen peroxide can be formed by other chemicals and during inflammation, and inflammation may accompany the outbreak of human diabetes, studies on the beneficiary effects of superoxide dismutase and other scavengers of free radicals in other forms of diabetes seem warranted. / <p>S. 1-38: sammanfattning, s. 39-74: Härtill 6 uppsatser</p> / digitalisering@umu

Barley protoplasts were shown to be a suitable experimental system for studies on the relative maximum during the decay of luminescence observed in most photosynthetic systems after excitation with far red light and in the presence of O2. The far red induced relative luminescence maximum was shown to be a result of three coinciding events: *Randomization of the S-states of the water splitting system during illumination with far red light. *Extreme oxidation of the PSII acceptor side after excitation with far red light and in the presence of O2. *Reverse coupling, causing partial re-reduction of the PSII acceptor side in the dark after far red illumination. When the CO2 concentration in the air above an intact barley leaf was lowered in the dark, the primary PSII acceptor QA was partially reduced. The effect was obtained by changes in CO2 over a wide concentration range including that of saturated photosynthesis. It was thus concluded that the effect was not related to the role of CO2 as the terminal electron acceptor in photosynthesis. White light induced relative maxima during the decay of luminescence frqm low CO2 adapted green algae were shown to be the result of either one or two interacting mechanisms: *Relaxation of qE quenching. *Dark reduction of QA occuring as a result of lowered internal Cj concentration in the dark. Far red induced luminescence decay kinetics and fluorescence induction kinetics, when analyzed with multivariat data analysis, were shown to contain information allowing prediction of the state of frost hardiness in artificially hardened seedlings of Scots pine. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1988, härtill 8 uppsatser.</p> / digitalisering@umu

This thesis investigates, at the country level, the relationship between innovation output or generation of new technology and input factors such as stock of knowledge, research effort and institutional factors such as competition and intellectual property rights. It is shown that variations in generation of new technology reflect differences in knowledge stock, research effort, product market competition and other institutional factors of OECD countries. The available stock of knowledge and the research effort was shown to have a linear and positive effect on technology generation. It was also shown that the degree of product market competition has a nonlinear effect on technology growth, thereby confirming on a country-level an inverted-U relationship between competition and innovation. Generation of new knowledge was examined using a knowledge production function with annual and accumulated knowledge measured with a patent indicator based on a worldwide count of patent priority filings. A cross-sectional linear regression model was used with secondary data. Independent variables included were the main variables accumulated stock of patent priority filings, the number of FTE researchers in R&amp;D and the Product Market Regulation Index. Institutional bias was accounted for by including the independent variables Index of Patent Rights, administrative patenting fees and a Global Competitiveness Index. The Global Competitiveness index was found to have positive effect on patent productivity and the administrative patenting fees relationship was found to be negative. The results are consistent with theories and empirical findings. The results also highlight the importance of innovation policies that keep costs of patenting low and of adjusting the competition policy of a country to the type of economy in question.

No description available.

The actual service loading histories of most engineering components are characterized by variable amplitudes and are sometimes rather complicated. The goal of this study was to estimate the fatigue life of nickel-chromium-molybdenum 30CrNiMo8HH steel alloy under axial and pure torsion variable amplitude loading (VAL) conditions. The investigation was directed at two primary factors that are believed to have an influence on fatigue life under such loading conditions: load sequence and mean stress. The experimental work for this research included two-step loading, non-zero mean strain loading, and VAL tests, the results of which were added to previously determined fully reversed strain-controlled fatigue data. The effect of load sequence on fatigue life was examined through the application of the commonly used linear damage accumulation rule along with the Manson and Marco–Starkey damage accumulation methods, the latter of which takes load sequence into account. Based on the two-step experimental results, both the Manson and Marco–Starkey methods were modified in order to eliminate the empirically determined constants normally required for these two methods. The effect of mean stress on fatigue life was investigated with the use of three life prediction models: Smith–Watson–Topper (SWT), Fatemi–Socie (FS), and Jahed–Varvani (JV). The cycles from the VAL histories were counted using a rainflow counting procedure that maintains the applied strain sequence, and a novel method was developed for the estimation of the total energy density required for the JV model. For two-step loading and for all three fatigue models employed, the modified damage accumulation methods provided superior fatigue life predictions. However, regardless of the damage accumulation method applied, the most satisfactory fatigue life correlation for VAL was obtained using the energy-based JV model.

129I is of major concern because of its biophilic nature, excessive inventory, long half-life (~16 million yrs), and high mobility in the natural environment that depends on its chemical speciation. Iodide (I-) has the highest mobility than iodate (IO3-) and is the predominant species in the terrestrial environment due to prevailing pH and Eh conditions. In order to transform I- to less mobile organo-iodine (OI), strong oxidants are necessary to activate the first electron transfer step from I- to reactive intermediates. The aim of this study was to determine the influence of naturally occurring aerobic bacteria isolated from an 129I contaminated aquifer (F-area of the Savannah River Site, SC) on I- oxidation and OI formation. It was demonstrated that 3 of 136 strains accumulated I- (0.2~2%) in the presence of H2O2, when incubated in the presence of an environmentally relevant concentration of I- (0.1 microM). The accumulation was likely through electrophilic substitution resulting in the iodination of cellular constituents. The results indicated that culturable I--accumulating bacteria are not directly responsible for the high fraction of oxidized iodine species (IO3- and OI, >50% of total I) present in the SRS F-area. Several bacterial strains were found to be capable of stimulating I- oxidation through excretion of oxidants and enzymes. Organic acids in spent liquid medium from 27 of 84 aerobic bacterial cultures enhanced H2O2-dependent I- oxidation 2-10 fold. Organic acids enhanced I- oxidation by (1) lowering the pH of the spent medium and (2) reacting with H2O2 to form peroxy carboxylic acids, which are strong oxidizing agents. In the absence of H2O2, spent medium from 44 of 84 bacteria cultures showed I- oxidizing capacities. One I- oxidizing bacterium was studied to characterize its extracellular I- oxidizing component(s). The I- oxidizing capability from the spent medium was inactive by treatments with heat and H2O2 and absent under anaerobic conditions. Conversely, NADH, NADPH and FMN additions stimulated I- oxidation in the spend medium. These results indicate an oxidase(s) catalyzed I- oxidation. Understanding the bacterial activities involved with I- oxidation and OI formation is expected to help reduce 129I mobility in water-soil systems.