143 research outputs found
Transition metals in superheat melts
A series of experiments with silicate melts doped with transition element oxides was carried out at atmospheric pressures of inert gas at temperatures exceeding liquidus. As predicted from the shape of fO2 buffer curves in T-fO2 diagrams the reducing conditions for a particular oxide-metal pair can be achieved through the T increase if the released oxygen is continuously removed. Experimental studies suggest that transition metals such as Cr or V behave as siderophile elements at temperatures exceeding liquidus temperatures if the system is not buffered by the presence of other oxide of more siderophile element. For example the presence of FeO prevents the reduction of Cr2O3. The sequence of decreasing siderophility of transition elements at superheat conditions (Mo, Ni, Fe, Cr) matches the decreasing degree of depletion of siderophile elements in mantle rocks as compared to chondrites
Die Strategische Rolle von Governance-Organen in Nonprofit Organisationen: Eine empirische Untersuchung der Zusammenhänge zwischen Kontext, Governance, Strategie und Performance im österreichischen Gesundheitssektor
Doctoral Thesis Rotterdam School of ManagementThis dissertation deals with the interface between governance and strategic management in nonprofit organizations (NPOs). The discussion and analysis focus on the influence of the governance process on strategic decision-making, in particular the interaction between the board members and the top management team (so-called interface governance). The aim of this research project has been to analyze the effects of this interface governance on organizations’ governance structure and the impact on organizational performance. The theoretical framework used in this dissertation is rooted in both the NPO governance and the strategic management literature. On the one hand, using NPO management and economic theories, a state of the art overview of governance in NPOs is presented. The typical characteristics of NPO organizations are discussed, as well as the consequences of such organizational peculiarities for both theory and practice. On the other hand, on the basis of strategic management literature – mostly coming from New Institutional Economics, stakeholder theory and resource-based view – a particular perspective on interface governance is presented. At the centre of attention are the factors, which in the context of interface governance can have an impact on the governance process and structure. On the basis of this theoretical framework, hypotheses have been formulated and tested, in a quantitative study using a sample of Austrian hospitals and old people's homes. An overall discussion of the research results and recommendations for a more efficient and effective interface governance in non-profit organizations can be found at the end of the dissertation
Elevation of plasma phospholipid transfer protein increases the risk of atherosclerosis despite lower apolipoprotein B-containing lipoproteins.
Plasma phospholipid transfer protein (PLTP) transfers phospholipids
between lipoproteins and mediates HDL conversion. PLTP-overexpressing mice
have increased atherosclerosis. However, mice do not express cholesteryl
ester transfer protein (CETP), which is involved in the same metabolic
pathways as PLTP. Therefore, we studied atherosclerosis in heterozygous
LDL receptor-deficient (LDLR(+/-)) mice expressing both human CETP and
human PLTP. We used two transgenic lines with moderately and highly
elevated plasma PLTP activity. In LDLR(+/-)/huCETPtg mice, cholesterol is
present in both LDL and HDL. Both are decreased in
LDLR(+/-)/huCETPtg/huPLTPtg mice (>50%). An atherogenic diet resulted in
high levels of VLDL+LDL cholesterol. PLTP expression caused a strong PLTP
dose-dependent decrease in VLDL and LDL cholesterol (-26% and -69%) and a
decrease in HDL cholesterol (-70%). Surprisingly, atherosclerosis was
increased in the two transgenic lines with moderately and highly elevated
plasma PLTP activity (1.9-fold and 4.4-fold, respectively), indicating
that the adverse effect of the reduction in plasma HDL outweighs the
beneficial effect of the reduction in apolipoprotein B (apoB)-containing
lipoproteins. The activities of the antiatherogenic enzymes paraoxonase
and platelet-activating factor acetyl hydrolase were both PLTP
dose-dependently reduced ( approximately -33% and -65%, respectively). We
conclude that expression of PLTP in this animal model results in increased
atherosclerosis in spite of reduced apoB-containing lipoproteins, by
reduction of HDL and of HDL-associated antioxidant enzyme activities
A Phospholipidomic Analysis of All Defined Human Plasma Lipoproteins
Since plasma lipoproteins contain both protein and phospholipid components, either may be involved in processes such as atherosclerosis. In this study the identification of plasma lipoprotein-associated phospholipids, which is essential for understanding these processes at the molecular level, are performed. LC-ESI/MS, LC-ESI-MS/MS and High Performance Thin Layer Chromatography (HPTLC) analysis of different lipoprotein fractions collected from pooled plasma revealed the presence of phosphatidylethanolamine (PE), phosphatidylinositol (PI), and sphingomyeline (SM) only on lipoproteins and phosphatidylcholine (PC), Lyso-PC on both lipoproteins and plasma lipoprotein free fraction (PLFF). Cardiolipin, phosphatidylglycerol (PG) and Phosphatidylserine (PS) were observed neither in the lipoprotein fractions nor in PLFF. All three approaches led to the same results regarding phospholipids occurrence in plasma lipoproteins and PLFF. A high abundancy of PE and SM was observed in VLDL and LDL fractions respectively. This study provides for the first time the knowledge about the phospholipid composition of all defined plasma lipoproteins
Characterisation of a ruthenium bipyridyl dye showing a long-lived charge-separated state on TiO<sub>2</sub> in the presence of I<sup>-</sup>/I<sub>3</sub><sup>-</sup>
Cancer Genomics Identifies Regulatory Gene Networks Associated with the Transition from Dysplasia to Advanced Lung Adenocarcinomas Induced by c-Raf-1
Background: Lung cancer is a leading cause of cancer morbidity. To improve an understanding of molecular causes of disease a transgenic mouse model was investigated where targeted expression of the serine threonine kinase c-Raf to respiratory epithelium induced initialy dysplasia and subsequently adenocarcinomas. This enables dissection of genetic events associated with precancerous and cancerous lesions. Methodology/Principal Findings: By laser microdissection cancer cell populations were harvested and subjected to whole genome expression analyses. Overall 473 and 541 genes were significantly regulated, when cancer versus transgenic and non-transgenic cells were compared, giving rise to three distinct and one common regulatory gene network. At advanced stages of tumor growth predominately repression of gene expression was observed, but genes previously shown to be upregulated in dysplasia were also up-regulated in solid tumors. Regulation of developmental programs as well as epithelial mesenchymal and mesenchymal endothelial transition was a hall mark of adenocarcinomas. Additionaly, genes coding for cell adhesion, i.e. the integrins and the tight and gap junction proteins were repressed, whereas ligands for receptor tyrosine kinase such as epi- and amphiregulin were up-regulated. Notably, Vegfr- 2 and its ligand Vegfd, as well as Notch and Wnt signalling cascades were regulated as were glycosylases that influence cellular recognition. Other regulated signalling molecules included guanine exchange factors that play a role in an activation of the MAP kinases while several tumor suppressors i.e. Mcc, Hey1, Fat3, Armcx1 and Reck were significantly repressed. Finally, probable molecular switches forcing dysplastic cells into malignantly transformed cells could be identified. Conclusions/Significance: This study provides insight into molecular pertubations allowing dysplasia to progress further to adenocarcinoma induced by exaggerted c-Raf kinase activity
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