6 resultados para Asymmetric pulmonary edema
em Doria (National Library of Finland DSpace Services) - National Library of Finland, Finland
Resumo:
The purpose of this study was to increase the understanding of the role and nature of trust in asymmetric technology partnership formation. In the knowledge-based "learning race" knowledge is considered as a primary source for competitive advantage. In the emerging ICT sector the high pace of technological change, the convergence of technologies and industries as well as the increasing complexity and uncertainty have forced even the largest players to seek cooperation for complementary knowledge and capabilities. Small technology firms need the complementary resources and legitimacy of the large firms to grow and compete in the global market place. Most of the earlier research indicates, however, that partnerships with asymmetric size, managerial resources and cultures have failed. A basic assumption supported by earlier research was that trust is a critical factor in asymmetric technology partnership formation. Asymmetric technology partnership formation is a dynamic and multi-dimensional process, and consequently a holistic research approach was selected. Research issue was approached from different levels: the individual decision-maker, the firm and the relationship between the parties. Also the impact of the dynamic environment and technology content was analyzed. A multitheoretical approach and a qualitative research method with in-depth interviews in five large ICT companies and eight small ICT companies enabled a holistic and rich view of the research issue. Study contributes on the scarce understanding on the nature and evolution of trust in asymmetric technology partnership formation. It sheds also light on the specific nature of asymmetric technology partnerships. The partnerships were found to be tentative and the diverse strategic intent of small and large technology firms appeared as a major challenge. The role of the boundary spanner was highlighted as a possibility to match the incompatible organizational cultures. A shared vision was found to be a pre-condition for individual-based fast trust leading to intuitive decision-making and experimentation. The relationships were tentative and they were continuously re-evaluated through the key actors' sense making of the technology content, asymmetry and the dynamic environment. A multi-dimensional conceptualization for trust was created and propositions on the role and nature of trust for further research are given. The purpose of this study was to increase the understanding of the role and nature of trust in asymmetric technology partnership formation. In the knowledge-based "learning race" knowledge is considered as a primary source for competitive advantage. In the emerging ICT sector the high pace of technological change, the convergence of technologies and industries as well as the increasing complexity and uncertainty have forced even the largest players to seek cooperation for complementary knowledge and capabilities. Small technology firms need the complementary resources and legitimacy of the large firms to grow and compete in the global market place. Most of the earlier research indicates, however, that partnerships with asymmetric size, managerial resources and cultures have failed. A basic assumption supported by earlier research was that trust is a critical factor in asymmetric technology partnership formation. Asymmetric technology partnership formation is a dynamic and multi-dimensional process, and consequently a holistic research approach was selected. Research issue was approached from different levels: the individual decision-maker, the firm and the relationship between the parties. Also the impact of the dynamic environment and technology content was analyzed. A multitheoretical approach and a qualitative research method with in-depth interviews in five large ICT companies and eight small ICT companies enabled a holistic and rich view of the research issue. Study contributes on the scarce understanding on the nature and evolution of trust in asymmetric technology partnership formation. It sheds also light on the specific nature of asymmetric technology partnerships. The partnerships were found to be tentative and the diverse strategic intent of small and large technology firms appeared as a major challenge. The role of the boundary spanner was highlighted as a possibility to match the incompatible organizational cultures. A shared vision was found to be a pre-condition for individual-based fast trust leading to intuitive decision-making and experimentation. The relationships were tentative and they were continuously re-evaluated through the key actors' sense making of the technology content, asymmetry and the dynamic environment. A multi-dimensional conceptualization for trust was created and propositions on the role and nature of trust for further research are given.
Resumo:
Acute lung injury (ALI) is a syndrome of acute hypoxemic respiratory failure with bilateral pulmonary infiltrates that is not caused by left atrial hypertension. Since there is no effective treatment available, this frequent clinical syndrome significantly contributes to mortality of both medical and surgical patients. Great majority of the patients with the syndrome suffers from indirect ALI caused by systemic inflammatory response syndrome (SIRS). Sepsis, trauma, major surgery and severe burns, which represent the most common triggers of SIRS, often induce an overwhelming inflammatory reaction leading to dysfunction of several vital organs. Studies of indirect ALI due to SIRS revealed that respiratory dysfunction results from increased permeability of endothelium. Disruption of endothelial barrier allows extravasation of protein-rich liquid and neutrophils to pulmonary parenchyma. Both under normal conditions and in inflammation, endothelial barrier function is regulated by numerous mechanisms. Endothelial enzymes represent one of the critical control points of vascular permeability and leukocyte trafficking. Some endothelial enzymes prevent disruption of endothelial barrier by production of anti-inflammatory substances. For instance, nitric oxide synthase (NOS) down-regulates leukocyte extravasation in inflammation by generation of nitric oxide. CD73 decreases vascular leakage and neutrophil emigration to inflamed tissues by generation of adenosine. On the other hand, vascular adhesion protein-1 (VAP-1) mediates leukocyte trafficking to the sites of inflammation both by generation of pro-inflammatory substances and by physically acting as an adhesion molecule. The aims of this study were to define the role of endothelial enzymes NOS, CD73 and VAP-1 in acute lung injury. Our data suggest that increasing substrate availability for NOS reduces both lung edema and neutrophil infiltration and this effect is not enhanced by concomitant administration of antioxidants. CD73 protects from vascular leakage in ALI and its up-regulation by interferon-β represents a novel therapeutic strategy for treatment of this syndrome. Enzymatic activity of VAP-1 mediates neutrophil infiltration in ALI and its inhibition represents an attractive approach to treat ALI.
Resumo:
Modifiering av metallytor med starkt adsorberade kirala organiska molekyler är eventuellt den mest relevanta teknik man vet i dag för att skapa kirala ytor. Den kan utnyttjas i katalytisk produktion av enantiomeriskt rena kirala föreningar som behövs t.ex. som läkemedel och aromkemikalier. Trots många fördelar av asymmetrisk heterogen katalys jämfört med andra sätt för att få kirala föreningar, har den ändå inte blivit ett allmänt verktyg för storskaliga tillämpningar. Detta beror t.ex. på brist på djupare kunskaper i katalytiska reaktionsmekanismer och ursprunget för asymmetrisk induktion. I denna studie användes molekylmodelleringstekniker för att studera asymmetriska, heterogena katalytiska system, speciellt hydrering av prokirala karbonylföreningar till motsvarande kirala alkoholer på cinchona-alkaloidmodifierade Pt-katalysatorer. 1-Fenyl-1,2-propandion (PPD) och några andra föreningar, som innehåller en prokiral C=O-grupp, användes som reaktanter. Konformationer av reaktanter och cinchona-alkaloider (som kallas modifierare) samt vätebundna 1:1-komplex mellan dem studerades i gas- och lösningsfas med metoder som baserar sig på vågfunktionsteori och täthetsfunktionalteori (DFT). För beräkningen av protonaffiniteter användes också högst noggranna kombinationsmetoder såsom G2(MP2). Den relativa populationen av modifierarnas konformationer varierade som funktion av modifieraren, dess protonering och lösningsmedlet. Flera reaktant–modifierareinteraktionsgeometrier beaktades. Slutsatserna på riktning av stereoselektivitet baserade sig på den relativa termodynamiska stabiliteten av de diastereomeriska reaktant–modifierare-komplexen samt energierna hos π- och π*-orbitalerna i den reaktiva karbonylgruppen. Adsorption och reaktioner på Pt(111)-ytan betraktades med DFT. Regioselektivitet i hydreringen av PPD och 2,3-hexandion kunde förklaras med molekyl–yta-interaktioner. Storleken och formen av klustret använt för att beskriva Pt-ytan inverkade inte bara på adsorptionsenergierna utan också på de relativa stabiliteterna av olika adsorptionsstrukturer av en molekyl. Populationerna av modifierarnas konformationer i gas- och lösningsfas korrelerade inte med populationerna på Pt-ytan eller med enantioselektiviteten i hydreringen av PPD på Pt–cinchona-katalysatorer. Vissa modifierares konformationer och reaktant–modifierare-interaktionsgeometrier var stabila bara på metallytan. Teoretiskt beräknade potentialenergiprofiler för hydrering av kirala α-hydroxiketoner på Pt implicerade preferens för parvis additionsmekanism för väte och selektiviteter i harmoni med experimenten. De uppnådda resultaten ökar uppfattningen om kirala heterogena katalytiska system och kunde därför utnyttjas i utvecklingen av nya, mera aktiva och selektiva kirala katalysatorer.
Resumo:
In this study, finite element analyses and experimental tests are carried out in order to investigate the effect of loading type and symmetry on the fatigue strength of three different non-load carrying welded joints. The current codes and recommendations do not give explicit instructions how to consider degree of bending in loading and the effect of symmetry in the fatigue assessment of welded joints. The fatigue assessment is done by using effective notch stress method and linear elastic fracture mechanics. Transverse attachment and cover plate joints are analyzed by using 2D plane strain element models in FEMAP/NxNastran and Franc2D software and longitudinal gusset case is analyzed by using solid element models in Abaqus and Abaqus/XFEM software. By means of the evaluated effective notch stress range and stress intensity factor range, the nominal fatigue strength is assessed. Experimental tests consist of the fatigue tests of transverse attachment joints with total amount of 12 specimens. In the tests, the effect of both loading type and symmetry on the fatigue strength is studied. Finite element analyses showed that the fatigue strength of asymmetric joint is higher in tensile loading and the fatigue strength of symmetric joint is higher in bending loading in terms of nominal and hot spot stress methods. Linear elastic fracture mechanics indicated that bending reduces stress intensity factors when the crack size is relatively large since the normal stress decreases at the crack tip due to the stress gradient. Under tensile loading, experimental tests corresponded with finite element analyzes. Still, the fatigue tested joints subjected to bending showed the bending increased the fatigue strength of non-load carrying welded joints and the fatigue test results did not fully agree with the fatigue assessment. According to the results, it can be concluded that in tensile loading, the symmetry of joint distinctly affects on the fatigue strength. The fatigue life assessment of bending loaded joints is challenging since it depends on whether the crack initiation or propagation is predominant.