991 resultados para Orthogonal polynomials in several variables
Resumo:
Five selective serotonin reuptake inhibitors (SSRIs) have been introduced recently: citalopram, fluoxetine, fluvoxamine, paroxetine and sertraline. Although no therapeutic window has been defined for SSRIs, in contrast to tricyclic antidepressants, analytical methods for therapeutic drug monitoring of SSRIs are useful in several instances. SSRIs differ widely in their chemical structure and in their metabolism. The fact that some of them have N-demethylated metabolites, which are also SSRIs, requires that methods be available which allow therapeutic drug monitoring of the parent compounds and of these active metabolites. most procedures are based on prepurification of the SSRIs by liquid-liquid extraction before they are submitted to separation by chromatographic procedures (high-performance liquid chromatography, gas chromatography, thin layer chromatography) and detection by various detectors (UV, fluorescence, electrochemical detector, nitrogen-phosphorus detector, mass spectrometry). This literature review shows that most methods allow quantitative determination of SSRIs in plasma, in the lower ng/ml range, and that they are, therefore, suitable for therapeutic drug monitoring purposes of this category of drugs.
Resumo:
Polyploidization, which is expected to trigger major genomic reorganizations, occurs much less commonly in animals than in plants, possibly because of constraints imposed by sex-determination systems. We investigated the origins and consequences of allopolyploidization in Palearctic green toads (Bufo viridis subgroup) from Central Asia, with three ploidy levels and different modes of genome transmission (sexual versus clonal), to (i) establish a topology for the reticulate phylogeny in a species-rich radiation involving several closely related lineages and (ii) explore processes of genomic reorganization that may follow polyploidization. Sibship analyses based on 30 cross-amplifying microsatellite markers substantiated the maternal origins and revealed the paternal origins and relationships of subgenomes in allopolyploids. Analyses of the synteny of linkage groups identified three markers affected by translocation events, which occurred only within the paternally inherited subgenomes of allopolyploid toads and exclusively affected the linkage group that determines sex in several diploid species of the green toad radiation. Recombination rates did not differ between diploid and polyploid toad species, and were overall much reduced in males, independent of linkage group and ploidy levels. Clonally transmitted subgenomes in allotriploid toads provided support for strong genetic drift, presumably resulting from recombination arrest. The Palearctic green toad radiation seems to offer unique opportunities to investigate the consequences of polyploidization and clonal transmission on the dynamics of genomes in vertebrates.
Resumo:
Previous studies assessed the outcome of ankle arthrodesis (AA) and total ankle replacement (TAR) surgeries; however, the extent of postoperative recovery towards bilateral gait mechanics (BGM) is unknown. We evaluated the outcome of the two surgeries at least 2 years post rehabilitation, focusing on BGM. 36 participants, including 12 AA patients, 12 TAR patients, and 12 controls were included. Gait assessment over 50 m distance was performed utilizing pressure insoles and 3D inertial sensors, following which an intraindividual comparison was performed. Most spatiotemporal and kinematic parameters in the TAR group were indicative of good gait symmetry, while the AA group presented significant differences. Plantar pressure symmetry among the AA group was also significantly distorted. Abnormality in biomechanical behavior of the AA unoperated, contralateral foot was observed. In summary, our results indicate an altered BGM in AA patients, whereas a relatively fully recovered BGM is observed in TAR patients, despite the quantitative differences in several parameters when compared to a healthy population. Our study supports a biomechanical assessment and rehabilitation of both operated and unoperated sides after major surgeries for ankle osteoarthrosis.
Resumo:
The Jalta and Jebel Ghozlane ore deposits are located in the extreme North of Tunisia, within the Nappe zone. The mineralization of Jalta, hosted in Triassic dolostones and the overlying Mio-Pliocene conglomerates, consists of abundant galena, barite, and cerussite with accessory sphalerite, pyrite, and jordanite. At Jebel Ghozlane, large Pb-Zn concentrations occur in the Triassic dolostones and Eocene limestones. The mineral association consists of galena, sphalerite, barite, and celestite and their oxidation products (cerussite, smithsonite, and anglesite). Lead isotope ratios in galena from both districts are relatively homogeneous ((206)Pb/(204)Pb = 18.702-18.823, (207)Pb/(204)Pb = 15.665-15.677, (208)Pb/(204)Pb = 38.725-38.875). The delta(34)S values for sulfates from both areas (+12.2 to +16.2 parts per thousand at Jalta and + 14.3 to + 19.4 parts per thousand at Jebel Ghozlane) are compatible with a derivation of sulfur from marine sulfates, possibly sourced from the Triassic evaporites. The delta(34)S values of the sulfides have a range between -10 and +12.5 parts per thousand at Jalta, and between -9.1 and +22.1 parts per thousand at Jebel Ghozlane. The large range of values suggests reduction of the sulfate by bacterial and/or thermochemical reduction of sulfate to sulfur. The high delta(34)S values of sulfides require closed-system reduction processes. The isotopically light carbon in late calcites (-6.3 to -2.5 parts per thousand) and authigenic dolomite (-17.6 parts per thousand) suggests an organic source of at least some of the carbon in these samples, whereas the similarity of the delta(18)O values between calcite (+24.8 parts per thousand) and the authigenic dolomite (+24.7 parts per thousand) of Jalta and their respective host rocks reflects oxygen isotope buffering of the mineralizing fluids by the host rock carbonates. The secondary calcite isotope compositions of Jalta are compatible with a hydrothermal fluid circulation at approximately 100 to 200 degrees C, but temperatures as low as 50 degrees C may be indicated by the late calcite of Jebel Ghozlane (delta(18)O of +35.9 parts per thousand). Given the geological events related to the Alpine orogeny in the Nappe zone (nappe emplacement, bimodal volcanism, and reactivation of major faults, such as Ghardimaou-Cap Serrat) and the Neogene age of the host rocks in several localities, a Late-Miocene age is proposed for the Pb-Zn ore deposits considered in this study. Remobilization of deep-seated primary deposits in the Paleozoic sequence is the most probable source for metals in both localities considered in this study and probably in the Nappe zone as a whole. (C) 2011 Elsevier B.V. All rights reserved.
Resumo:
Muscle dysfunction often occurs in patients with chronic obstructive pulmonary disease (COPD) and may involve both respiratory and locomotor (peripheral) muscles. The loss of strength and/or endurance in the former can lead to ventilatory insufficiency, whereas in the latter it limits exercise capacity and activities of daily life. Muscle dysfunction is the consequence of complex interactions between local and systemic factors, frequently coexisting in COPD patients. Pulmonary hyperinflation along with the increase in work of breathing that occur in COPD appear as the main contributing factors to respiratory muscle dysfunction. By contrast, deconditioning seems to play a key role in peripheral muscle dysfunction. However, additional systemic factors, including tobacco smoking, systemic inflammation, exercise, exacerbations, nutritional and gas exchange abnormalities, anabolic insufficiency, comorbidities and drugs, can also influence the function of both respiratory and peripheral muscles, by inducing modifications in their local microenvironment. Under all these circumstances, protein metabolism imbalance, oxidative stress, inflammatory events, as well as muscle injury may occur, determining the final structure and modulating the function of different muscle groups. Respiratory muscles show signs of injury as well as an increase in several elements involved in aerobic metabolism (proportion of type I fibers, capillary density, and aerobic enzyme activity) whereas limb muscles exhibit a loss of the same elements, injury, and a reduction in fiber size. In the present review we examine the current state of the art of the pathophysiology of muscle dysfunction in COPD.
Resumo:
The markets of biomass for energy are developing rapidly and becoming more international. A remarkable increase in the use of biomass for energy needs parallel and positive development in several areas, and there will be plenty of challenges to overcome. The main objective of the study was to clarify the alternative future scenarios for the international biomass market until the year 2020, and based on the scenario process, to identify underlying steps needed towards the vital working and sustainable biomass market for energy purposes. Two scenario processes were conducted for this study. The first was carried out with a group of Finnish experts and thesecond involved an international group. A heuristic, semi-structured approach, including the use of preliminary questionnaires as well as manual and computerised group support systems (GSS), was applied in the scenario processes.The scenario processes reinforced the picture of the future of international biomass and bioenergy markets as a complex and multi-layer subject. The scenarios estimated that the biomass market will develop and grow rapidly as well as diversify in the future. The results of the scenario process also opened up new discussion and provided new information and collective views of experts for the purposes of policy makers. An overall view resulting from this scenario analysis are the enormous opportunities relating to the utilisation of biomass as a resource for global energy use in the coming decades. The scenario analysis shows the key issues in the field: global economic growth including the growing need for energy, environmental forces in the global evolution, possibilities of technological development to solve global problems, capabilities of the international community to find solutions for global issues and the complex interdependencies of all these driving forces. The results of the scenario processes provide a starting point for further research analysing the technological and commercial aspects related the scenarios and foreseeing the scales and directions of biomass streams.
Resumo:
Even though the research on innovation in services has expanded remarkably especially during the past two decades, there is still a need to increase understanding on the special characteristics of service innovation. In addition to studying innovation in service companies and industries, research has also recently focused more on services in innovation, as especially the significance of so-called knowledge intensive business services (KIBS) for the competitive edge of their clients, othercompanies, regions and even nations has been proved in several previous studies. This study focuses on studying technology-based KIBS firms, and technology andengineering consulting (TEC) sector in particular. These firms have multiple roles in innovation systems, and thus, there is also a need for in-depth studies that increase knowledge about the types and dimensions of service innovations as well as underlying mechanisms and procedures which make the innovations successful. The main aim of this study is to generate new knowledge in the fragmented research field of service innovation management by recognizing the different typesof innovations in TEC services and some of the enablers of and barriers to innovation capacity in the field, especially from the knowledge management perspective. The study also aims to shed light on some of the existing routines and new constructions needed for enhancing service innovation and knowledge processing activities in KIBS companies of the TEC sector. The main samples of data in this research include literature reviews and public data sources, and a qualitative research approach with exploratory case studies conducted with the help of the interviews at technology consulting companies in Singapore in 2006. These complement the qualitative interview data gathered previously in Finland during a larger research project in the years 2004-2005. The data is also supplemented by a survey conducted in Singapore. The respondents for the survey by Tan (2007) were technology consulting companies who operate in the Singapore region. The purpose ofthe quantitative part of the study was to validate and further examine specificaspects such as the influence of knowledge management activities on innovativeness and different types of service innovations, in which the technology consultancies are involved. Singapore is known as a South-east Asian knowledge hub and is thus a significant research area where several multinational knowledge-intensive service firms operate. Typically, the service innovations identified in the studied TEC firms were formed by several dimensions of innovations. In addition to technological aspects, innovations were, for instance, related to new client interfaces and service delivery processes. The main enablers of and barriers to innovation seem to be partly similar in Singaporean firms as compared to the earlier study of Finnish TEC firms. Empirical studies also brought forth the significance of various sources of knowledge and knowledge processing activities as themain driving forces of service innovation in technology-related KIBS firms. A framework was also developed to study the effect of knowledge processing capabilities as well as some moderators on the innovativeness of TEC firms. Especially efficient knowledge acquisition and environmental dynamism seem to influence the innovativeness of TEC firms positively. The results of the study also contributeto the present service innovation literature by focusing more on 'innovation within KIBs' rather than 'innovation through KIBS', which has been the typical viewpoint stressed in the previous literature. Additionally, the study provides several possibilities for further research.
Resumo:
Theultimate goal of any research in the mechanism/kinematic/design area may be called predictive design, ie the optimisation of mechanism proportions in the design stage without requiring extensive life and wear testing. This is an ambitious goal and can be realised through development and refinement of numerical (computational) technology in order to facilitate the design analysis and optimisation of complex mechanisms, mechanical components and systems. As a part of the systematic design methodology this thesis concentrates on kinematic synthesis (kinematic design and analysis) methods in the mechanism synthesis process. The main task of kinematic design is to find all possible solutions in the form of structural parameters to accomplish the desired requirements of motion. Main formulations of kinematic design can be broadly divided to exact synthesis and approximate synthesis formulations. The exact synthesis formulation is based in solving n linear or nonlinear equations in n variables and the solutions for the problem areget by adopting closed form classical or modern algebraic solution methods or using numerical solution methods based on the polynomial continuation or homotopy. The approximate synthesis formulations is based on minimising the approximation error by direct optimisation The main drawbacks of exact synthesis formulationare: (ia) limitations of number of design specifications and (iia) failure in handling design constraints- especially inequality constraints. The main drawbacks of approximate synthesis formulations are: (ib) it is difficult to choose a proper initial linkage and (iib) it is hard to find more than one solution. Recentformulations in solving the approximate synthesis problem adopts polynomial continuation providing several solutions, but it can not handle inequality const-raints. Based on the practical design needs the mixed exact-approximate position synthesis with two exact and an unlimited number of approximate positions has also been developed. The solutions space is presented as a ground pivot map but thepole between the exact positions cannot be selected as a ground pivot. In this thesis the exact synthesis problem of planar mechanism is solved by generating all possible solutions for the optimisation process ¿ including solutions in positive dimensional solution sets - within inequality constraints of structural parameters. Through the literature research it is first shown that the algebraic and numerical solution methods ¿ used in the research area of computational kinematics ¿ are capable of solving non-parametric algebraic systems of n equations inn variables and cannot handle the singularities associated with positive-dimensional solution sets. In this thesis the problem of positive-dimensional solutionsets is solved adopting the main principles from mathematical research area of algebraic geometry in solving parametric ( in the mathematical sense that all parameter values are considered ¿ including the degenerate cases ¿ for which the system is solvable ) algebraic systems of n equations and at least n+1 variables.Adopting the developed solution method in solving the dyadic equations in direct polynomial form in two- to three-precision-points it has been algebraically proved and numerically demonstrated that the map of the ground pivots is ambiguousand that the singularities associated with positive-dimensional solution sets can be solved. The positive-dimensional solution sets associated with the poles might contain physically meaningful solutions in the form of optimal defectfree mechanisms. Traditionally the mechanism optimisation of hydraulically driven boommechanisms is done at early state of the design process. This will result in optimal component design rather than optimal system level design. Modern mechanismoptimisation at system level demands integration of kinematic design methods with mechanical system simulation techniques. In this thesis a new kinematic design method for hydraulically driven boom mechanism is developed and integrated in mechanical system simulation techniques. The developed kinematic design method is based on the combinations of two-precision-point formulation and on optimisation ( with mathematical programming techniques or adopting optimisation methods based on probability and statistics ) of substructures using calculated criteria from the system level response of multidegree-of-freedom mechanisms. Eg. by adopting the mixed exact-approximate position synthesis in direct optimisation (using mathematical programming techniques) with two exact positions and an unlimitednumber of approximate positions the drawbacks of (ia)-(iib) has been cancelled.The design principles of the developed method are based on the design-tree -approach of the mechanical systems and the design method ¿ in principle ¿ is capable of capturing the interrelationship between kinematic and dynamic synthesis simultaneously when the developed kinematic design method is integrated with the mechanical system simulation techniques.
Resumo:
The driving forces of technology and globalization continuously transform the business landscape in a way which undermines the existing strategies and innovations of organizations. The challenge for organizations is to establish such conditions where they are able to create new knowledge for innovative business ideas in interaction between other organizations and individuals. Innovation processes continuously need new external stimulations and seek new ideas, new information and knowledge locating more and more outside traditional organizational boundaries. In several studies, the early phases of the innovation process have been considered as the most critical ones. During these phases, the innovation process can emerge or conclude. External knowledge acquirement and utilization are noticed to be important at this stage of the innovation process giving information about the development of future markets and needs for new innovative businessideas. To make it possible, new methods and approaches to manage proactive knowledge creation and sharing activities are needed. In this study, knowledge creation and sharing in the early phases of the innovation process has been studied, and the understanding of knowledge management in the innovation process in an open and collaborative context advanced. Furthermore, the innovation management methods in this study are combined in a novel way to establish an open innovation process and tested in real-life cases. For these purposes two complementary and sequentially applied group work methods - the heuristic scenario method and the idea generation process - are examined by focusing the research on the support of the open knowledge creation and sharing process. The research objective of this thesis concerns two doctrines: the innovation management including the knowledge management, and the futures research concerning the scenario paradigm. This thesis also applies the group decision support system (GDSS) in the idea generation process to utilize the converged knowledge during the scenario process.
Resumo:
Tutkimus keskittyy hankintatoimen kehittämiseen osana laitosprojektien toteutusta. Työ pohjautuu empiiriseltä taustaltaan Pöyry Oyj:n projektiliiketoimintaan ja työn tarkastelunäkökulmaksi onvalittu projektihallinnosta vastaavan yrityksen näkökulma. Tutkimus on hyvin käytännönläheinen ¿ se lähtee hankinnan ja sen seurannan ongelmista ja pyrkii tarjoamaan niihin uudenlaisia ratkaisuja. Pohjimmiltaan tutkimus kuuluu teollisuustalouden piiriin, vaikka tietojärjestelmätieteellä on vahva tukirooli. Työn tavoitteet ja tulokset liittyvät teollisuustaloudelle ominaisesti yrityksen toiminnan kehittämiseen, käytetyt välineet ja ratkaisut puolestaan hyödyntävät tietojärjestelmätieteen antamia mahdollisuuksia. Tutkimuksessa on käytetty konstruktiivista tutkimusotetta, jonka mukaisesti on luotu innovatiivisia konstruktioita ratkaisemaan aitoja reaalimaailman ongelmia ja tätä kautta tuotettu kontribuutioita teollisuustaloudelle. Tavoitteena oli järjestää hankintatoimi ja sen seuranta suurissa laitosprojekteissa tehokkaammin. Tätä varten uudistettiin ensin projektihallinnon ja hankintatoimen toimintaohjeet vastaamaan paremmin nykyajan vaatimuksia. Toimintaohjeiden perusteella ryhdyttiin toteuttamaan hankintaohjelmistoa, joka pystyisi kattamaan kaikki toimintaohjeissa kuvatut piirteet. Lopulta hankintaohjelmisto toi mukanaan uusia piirteitä projektihallintoon ja hankintatoimeen ja nämä sisällytettiin toimintaohjeisiin. Tähän kehitystyöhön ryhdyttiin, jotta laitosprojektien projektihallinto ja hankintatoimi toimisivat paremmin, eli pienemmin kustannuksin tuottaen projekteissa tarvittavat tulokset nopeammin, tarkemmin ja laadukkaammin. Tutkimuksella on kolmenlaisia tuloksia: hankintatoimen parannetut metodit, hankintaohjelmiston pohjana olevat toiminta- ja laskentamallit sekä implementaationa hankintasovellus. Uudistetut projekti- ja hankintaohjeet kuvaavat hankintatoiminnan parannettuja metodeja. Hankintaohjelmistoasuunnitellessa ja kehitettäessä tehdyt kuvaukset sisältävät uusia malleja niin hankintaprosessille kuin hankinnan seuraamiseksi suurissa laitosprojekteissa. Itse ohjelmisto on tuloksena implementaatio, joka perustuu parannettuihin hankintametodeihin ja uusiin toiminta- ja laskentamalleihin. Uudistetut projekti- ja hankintaohjeet ovat olleet käytössä Pöyry Oyj:ssä vuodesta 1991. Vuosien varrella nämä toimintaohjeet ovat auttaneet ja tukeneet satojen laitosprojektientoteutusta ja ylläpitäneet Pöyry Oyj:n kilpailukykyä kansainvälisenä projektitalona. Hankintasovellus puolestaan on ollut käytössä useissa projekteissa ja sen on havaittu pienentävän hankintatoimen suoria työkustannuksia laitosprojekteissa. Sovelluksen katsotaan myös tuovan epäsuoria kustannussäästöjä parempien hankintapäätösten muodossa, mutta näiden säästöjen suuruutta ei pystytä luotettavasti arvioimaan.
Resumo:
Values and value processes are said to be needed in every organization nowadays, as the world is changing and companies have to have something to "keep it together". Organizational values, which are approvedand used by the personnel, could be the key. Every organization has values. But what is the real value of values? The greatest and most crucial challenge is the feasibility of the value process. The main point in this thesis is tostudy how organizational members at different hierarchical levels perceive values and value processes in their organizations. This includes themes such as how values are disseminated, the targets of value processing, factors that affect the process, problems that occur during the value implementation and improvements that could be made when organizational values are implemented. These subjects are studied from the perspective of organizational members (both managers and employees); individuals in the organizations. The aim is to get the insider-perspective on value processing, from multiple hierarchical levels. In this research I study three different organizations (forest industry, bank and retail cooperative) and their value processes. The data is gathered from companies interviewing personnel in the head office and at the local level. The individuals areseen as members of organizations, and the cultural aspect is topical throughout the whole study. Values and cultures are seen as the 'actuality of reality' of organizations, interpreted by organizational members. The three case companies were chosen because they represented different lines of business and they all implemented value processing differently. Sincethe emphasis in this study is at the local level, the similar size of the local units was also an important factor. Values are in 'fashion' -but what does the fashion tell us about the real corporate practices? In annual reports companies emphasize the importance and power of official values. But what is the real 'point' of values? Values are publicly respected and advertised, but still it seems that the words do not meet the deeds. There is a clear conflict between theoretical, official and substantive organizational values: in the value processing from words to real action. This contradiction in value processing is studied through individual perceptions in this study. I study the kinds of perceptions organizationalmembers have when values are processed from the head office to the local level: the official value process is studied from the individual's perspective. Value management has been studied more during the 1990's. The emphasis has usually been on managers: how they consider the values in organizations and what effects it has on the management. Recent literature has emphasized values as tools for improving company performance. The value implementation as a process has been studied through 'good' and 'bad' examples, as if one successful value process could be copied to all organizations. Each company is different with different cultures and personnel, so no all-powerful way of processing values exists. In this study, the organizational members' perceptions at different hierarchical levels are emphasized. Still, managers are also interviewed; this is done since managerial roles in value dissemination are crucial. Organizational values cannot be well disseminated without management; this has been proved in several earlier studies (e.g. Kunda 1992, Martin 1992, Parker 2000). Recent literature has not sufficiently emphasized the individual's (organizational member's) role in value processing. Organizations consist of differentindividuals with personal values, at all hierarchical levels. The aim in this study is to let the individual take the floor. Very often the value process is described starting from the value definition and ending at dissemination, and the real results are left without attention. I wish to contribute to this area. Values are published officially in annual reports etc. as a 'goal' just like profits. Still, the results/implementationof value processing is rarely followed, at least in official reports. This is a very interesting point: why do companies espouse values, if there is no real control or feedback after the processing? In this study, the personnel in three different companies is asked to give an answer. In the empirical findings, there are several results which bring new aspects to the research area of organizational values. The targets of value processing, factors effecting value processing, the management's roles and the problems in value implementation are presented through the individual's perspective. The individual's perceptions in value processing are a recurring theme throughout the whole study. A comparison between the three companies with diverse value processes makes the research complete
Resumo:
Software engineering is criticized as not being engineering or 'well-developed' science at all. Software engineers seem not to know exactly how long their projects will last, what they will cost, and will the software work properly after release. Measurements have to be taken in software projects to improve this situation. It is of limited use to only collect metrics afterwards. The values of the relevant metrics have to be predicted, too. The predictions (i.e. estimates) form the basis for proper project management. One of the most painful problems in software projects is effort estimation. It has a clear and central effect on other project attributes like cost and schedule, and to product attributes like size and quality. Effort estimation can be used for several purposes. In this thesis only the effort estimation in software projects for project management purposes is discussed. There is a short introduction to the measurement issues, and some metrics relevantin estimation context are presented. Effort estimation methods are covered quite broadly. The main new contribution in this thesis is the new estimation model that has been created. It takes use of the basic concepts of Function Point Analysis, but avoids the problems and pitfalls found in the method. It is relativelyeasy to use and learn. Effort estimation accuracy has significantly improved after taking this model into use. A major innovation related to the new estimationmodel is the identified need for hierarchical software size measurement. The author of this thesis has developed a three level solution for the estimation model. All currently used size metrics are static in nature, but this new proposed metric is dynamic. It takes use of the increased understanding of the nature of the work as specification and design work proceeds. It thus 'grows up' along with software projects. The effort estimation model development is not possible without gathering and analyzing history data. However, there are many problems with data in software engineering. A major roadblock is the amount and quality of data available. This thesis shows some useful techniques that have been successful in gathering and analyzing the data needed. An estimation process is needed to ensure that methods are used in a proper way, estimates are stored, reported and analyzed properly, and they are used for project management activities. A higher mechanism called measurement framework is also introduced shortly. The purpose of the framework is to define and maintain a measurement or estimationprocess. Without a proper framework, the estimation capability of an organization declines. It requires effort even to maintain an achieved level of estimationaccuracy. Estimation results in several successive releases are analyzed. It isclearly seen that the new estimation model works and the estimation improvementactions have been successful. The calibration of the hierarchical model is a critical activity. An example is shown to shed more light on the calibration and the model itself. There are also remarks about the sensitivity of the model. Finally, an example of usage is shown.
Resumo:
Building and sustaining competitive advantage through the creation of market imperfections is challenging in a constantly changing business environment - particularly since the sources of such advantages are increasingly knowledge-based. Facilitated by improved networks and communication, knowledge spills over to competitors more easily than before,thus creating an appropriability problem: the inability of an innovating firm to utilize its innovations commercially. Consequently, as the importance of intellectual assets increases, their protection also calls for new approaches. Companies have various means of protection at their disposal, and by taking advantage of them they can make intangibles more non-transferable and prevent, or at leastdelay, imitation of their most crucial intellectual assets. However, creating barriers against imitation has another side to it, and the transfer of knowledge in situations requiring knowledge sharing may be unintentionally obstructed. Theaim of this thesis is to increase understanding of how firms can balance knowledge protection and sharing so as to benefit most from their knowledge assets. Thus, knowledge protection is approached through an examination of the appropriability regime of a firm, i.e., the combination of available and effective means ofprotecting innovations, their profitability, and the increased rents due to R&D. A further aim is to provide a broader understanding of the formation and structure of the appropriability regime. The study consists of two parts. The first part introduces the research topic and the overall results of the study, and the second part consists of six complementary research publications covering various appropriability issues. The thesis contributes to the existing literature in several ways. Although there is a wide range of prior research on appropriability issues, a lot of it is restricted either to the study of individual appropriability mechanisms, or to comparing certain features of them. These approaches are combined, and the relevant theoretical concepts are clarified and developed. In addition, the thesis provides empirical evidence of the formation of the appropriability regime, which is consequently presented as an adaptive process. Thus, a framework is provided that better corresponds to the complex reality of the current business environment.
Resumo:
Intrinsic resistance to the epidermal growth factor receptor (EGFR; HER1) tyrosine kinase inhibitor (TKI) gefitinib, and more generally to EGFR TKIs, is a common phenomenon in breast cancer. The availability of molecular criteria for predicting sensitivity to EGFR-TKIs is, therefore, the most relevant issue for their correct use and for planning future research. Though it appears that in non-small-cell lung cancer (NSCLC) response to gefitinib is directly related to the occurrence of specific mutations in the EGFR TK domain, breast cancer patients cannot be selected for treatment with gefitinib on the same basis as such EGFR mutations have beenreported neither in primary breast carcinomas nor in several breast cancer cell lines. Alternatively, there is a generalagreement on the hypothesis that the occurrence of molecular alterations that activate transduction pathways downstreamof EGFR (i.e., MEK1/MEK2 - ERK1/2 MAPK and PI-3'K - AKT growth/survival signaling cascades) significantly affect the response to EGFR TKIs in breast carcinomas. However,there are no studies so far addressing a role of EGF-related ligands as intrinsic breast cancer cell modulators of EGFR TKIefficacy. We recently monitored gene expression profiles andsub-cellular localization of HER-1/-2/-3/-4 related ligands (i.e., EGF, amphiregulin, transforming growth factor-α, ß-cellulin,epiregulin and neuregulins) prior to and after gefitinib treatment in a panel of human breast cancer cell lines. First, gefitinibinduced changes in the endogenous levels of EGF-related ligands correlated with the natural degree of breast cancer cellsensitivity to gefitinib. While breast cancer cells intrinsically resistant to gefitinib (IC50 ≥15 μM) markedly up-regulated(up to 600 times) the expression of genes codifying for HERspecific ligands, a significant down-regulation (up to 106 times)of HER ligand gene transcription was found in breast cancer cells intrinsically sensitive to gefitinib (IC50 ≤1 μM). Second,loss of HER1 function differentially regulated the nuclear trafficking of HER-related ligands. While gefitinib treatment induced an active import and nuclear accumulation of the HER ligand NRG in intrinsically gefitinib-resistant breastcancer cells, an active export and nuclear loss of NRG was observed in intrinsically gefitinib-sensitive breast cancer cells.In summary, through in vitro and pharmacodynamic studies we have learned that, besides mutations in the HER1 gene,oncogenic changes downstream of HER1 are the key players regulating gefitinib efficacy in breast cancer cells. It now appears that pharmacological inhibition of HER1 functionalso leads to striking changes in both the gene expression and the nucleo-cytoplasmic trafficking of HER-specific ligands,and that this response correlates with the intrinsic degree of breast cancer sensitivity to the EGFR TKI gefitinib. Therelevance of this previously unrecognized intracrine feedback to gefitinib warrants further studies as cancer cells could bypassthe antiproliferative effects of HER1-targeted therapeutics without a need for the overexpression and/or activation of other HER family members and/or the activation of HER-driven downstream signaling cascades
Resumo:
Deficiency of protease-activated receptor-2 (PAR2) modulates inflammation in several models of inflammatory and autoimmune disease, although the underlying mechanism(s) are not understood. PAR2 is expressed on endothelial and immune cells, and is implicated in dendritic cell (DC) differentiation. We investigated in vivo the impact of PAR2 activation on DCs and T cells in PAR2 wild-type (WT) and knockout (KO) mice using a specific PAR2 agonist peptide (AP2). PAR2 activation significantly increased the frequency of mature CD11c(high) DCs in draining lymph nodes 24 hr after AP2 administration. Furthermore, these DCs exhibited increased expression of major histocompatibility complex (MHC) class II and CD86. A significant increase in activated (CD44(+) CD62(-)) CD4(+) and CD8(+) T-cell frequencies was also observed in draining lymph nodes 48 hr after AP2 injection. No detectable change in DC or T-cell activation profiles was observed in the spleen. The influence of PAR2 signalling on antigen transport to draining lymph nodes was assessed in the context of delayed-type hypersensitivity. PAR2 WT mice that were sensitized by skin-painting with fluorescein isothiocyanate (FITC) to induce delayed-type hypersensitivity possessed elevated proportion of FITC(+) DCs in draining lymph nodes 24 hr after FITC painting when compared with PAR2 KO mice (0.95% versus 0.47% of total lymph node cells). Collectively, these results demonstrate that PAR2 signalling promotes DC trafficking to the lymph nodes and subsequent T-cell activation, and thus provides an explanation for the pro-inflammatory effect of PAR2 in animal models of inflammation.