76 resultados para OHMIC CONTACTS
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In this thesis, the contact resistance of graphene devices was investigated because high contact resistance is detrimental to the performance of graphene field-effect transistors (GFET). Method for increasing so-called edge-contact area was applied in device fabrication process, as few nanometers thick Ni layer was used as a catalytic etchant during the annealing process. Finally, Ni was also used as a metal for contact. GFETs were fabricated using electron beam lithography using graphene fabricated by chemical vapor deposition (CVD). Critical part of the fabrication process was to preserve the high quality of the graphene channel while etching the graphene at contact areas with Ni during the annealing. This was achieved by optimizing the combination of temperature and gas flows. The structural properties of graphene were studied using scanning electron microscopy, scanning confocal μ-Raman spectroscopy and optical microscopy. Evaluation of electric transport properties including contact resistance was carried out by transmission line method and four-probe method. The lowest contact resistance found was about at 350 Ωμm. In addition, different methods to transfer CVD graphene synthesized on copper were studied. Typical method using PMMA as a supporting layer leaves some residues after its removal, thus effecting on the performance of a graphene devices. In a metal assisted transfer method, metal is used as an interfacial layer between PMMA and graphene. This allows more effective removal of PMMA. However, Raman spectra of graphene transferred by metal assisted method showed somewhat lower quality than the PMMA assisted method
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Presentation at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014
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This study looks at negotiation of belonging and understandings of home among a generation of young Kurdish adults who were born in Iraq, Iran, and Turkey and who reached adulthood in Finland. The young Kurds taking part in the study belong to the generation of migrants who moved to Finland in their childhood and early teenage years from the region of Kurdistan and elsewhere in the Middle East, then grew to adulthood in Finland. In theoretical terms, the study draws broadly from three approaches: transnationalism, intersectionality, and narrativity. Transnationalism refers to individuals’ cross-border ties and interaction extending beyond nationstates’ borders. Young people of migrant background, it has been suggested, are raised in a transnational space that entails cross-border contacts, ties, and visits to the societies of departure. How identities and feelings of belonging become formed in relation to the transnational space is approached with an intersectional frame, for examination of individuals’ positionings in terms of their intersecting attributes of gender, age/generation, and ethnicity, among others. Focus on the narrative approach allows untangling how individuals make sense of their place in the social world and how they narrate their belonging in terms of various mechanisms of inclusion and exclusion, including institutional arrangements and discursive categorisation schemes. The empirical data for this qualitative study come from 25 semi-structured thematic interviews that were conducted with 23 young Kurdish adults living in Turku and Helsinki between 2009 and 2011. The interviewees were aged between 19 and 28 years at the time of interviewing. Interview themes involved topics such as school and working life, family relations and language-learning, political activism and citizenship, transnational ties and attachments, belonging and identification, and plans for the future and aspirations. Furthermore, data were collected from observations during political demonstrations and meetings, along with cultural get-togethers. The data were analysed via thematic analysis. The findings from the study suggest that young Kurds express a strong sense of ‘Kurdishness’ that is based partially on knowing the Kurdish language and is informed by a sense of cultural continuity in the diaspora setting. Collective Kurdish identity narratives, particularly related to the consciousness of being a marginalised ‘other’ in the context of the Middle East, are resonant in young interviewees’ narrations of ‘Kurdishness’. Thus, a sense of ‘Kurdishness’ is drawn from lived experiences indexed to a particular politico-historical context of the Kurdish diaspora movements but also from the current situation of Kurdish minorities in the Middle East. On the other hand, young Kurds construct a sense of belonging in terms of the discursive constructions of ‘Finnishness’ and ‘otherness’ in the Finnish context. The racialised boundaries of ‘Finnishness’ are echoed in young Kurds’ narrations and position them as the ‘other’ – namely, the ‘immigrant’, ‘refugee’, or ‘foreigner’ – on the basis of embodied signifiers (specifically, their darker complexions). This study also indicates that young Kurds navigate between gendered expectations and norms at home and outside the home environment. They negotiate their positionings through linguistic repertoires – for instance, through mastery of the Finnish language – and by adjusting their behaviour in light of the context. This suggests that young Kurds adopt various forms of agency to display and enact their belonging in a transnational diaspora space. Young Kurds’ narrations display both territorially-bounded and non-territorially-bounded elements with regard to the relationship between identity and locality. ‘Home’ is located in Finland, and the future and aspirations are planned in relation to it. In contrast, the region of Kurdistan is viewed as ‘homeland’ and as the place of origins and roots, where temporary stays and visits are a possibility. The emotional attachments are forged in relation to the country (Finland) and not so much relative to ‘Finnishness’, which the interviewees considered an exclusionary identity category. Furthermore, identification with one’s immediate place of residence (city) or, in some cases, with a religious identity as ‘Muslim’ provides a more flexible venue for identification than does identifying oneself with the (Finnish) nation.
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The human immune system is constantly interacting with the surrounding stimuli and microorganisms. However, when directed against self or harmless antigens, these vital defense mechanisms can cause great damage. In addition, the understanding the underlying mechanism of several human diseases caused by aberrant immune cell functions, for instance type 1 diabetes and allergies, remains far from being complete. In this Ph.D. study these questions were addressed using genome-wide transcriptomic analyses. Asthma and allergies are characterized by a hyperactive response of the T helper 2 (Th2) immune cells. In this study, the target genes of the STAT6 transcription factor in naïve human T cells were identified with RNAi for the first time. STAT6 was shown to act as a central activator of the genes expression upon IL-4 signaling, with both direct and indirect effects on Th2 cell transcriptome. The core transcription factor network induced by IL-4 was identified from a kinetic analysis of the transcriptome. Type 1 diabetes is an autoimmune disease influenced by both the genetic susceptibility of an individual and the disease-triggering environmental factors. To improve understanding of the autoimmune processes driving pathogenesis in the prediabetic phase in humans, a unique series of prospective whole-blood RNA samples collected from HLA-susceptible children in the Finnish Type 1 Diabetes Prediction and Prevention (DIPP) study was studied. Changes in different timewindows of the pathogenesis process were identified, and especially the type 1 interferon response was activated early and throughout the preclinical T1D. The hygiene hypothesis states that allergic diseases, and lately also autoimmune diseases, could be prevented by infections and other microbial contacts acquired in early childhood, or even prenatally. To study the effects of the standard of hygiene on the development of neonatal immune system, cord blood samples from children born in Finland (high standard of living), Estonia (rapid economic growth) and Russian Karelia (low standard of living) were compared. Children born in Russian Karelia deviated from Finnish and Estonian children in many aspects of the neonatal immune system, which was developmentally more mature in Karelia, resembling that of older infants. The results of this thesis offer significant new information on the regulatory networks associated with immune-mediated diseases in human. The results will facilitate understanding and further research on the role of the identified target genes and mechanisms driving the allergic inflammation and type 1 diabetes, hopefully leading to a new era of drug development.
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Tutkimuksen ensimmäinen tavoite on kaksiosainen. Aluksi pyrittiin selvittämään, kuinka voittoa tavoittelemattomalla sektorilla voidaan mitata asiakashankinnan suorituskykyä. Toiseksi tutkittiin, mikä on mittauksen tila Suomen voittoa tavoittelemattomassa sektorissa. Toinen tavoite oli rakentaa suorituskykymittaristo suurehkon järjestön asiakashankintaan ja pohtia asiakashankinnan tavoitteiden jalkauttamista mittareiden avulla. Ensimmäinen tavoite toteutettiin kirjallisuuskatsauksen ja kyselytutkimuksen avulla. Kirjallisuuskatsauksen perusteella rakennettiin kyselylomake, jota jaettiin suomalaisiin voittoa tavoittelemattomiin organisaatioihin. Kirjallisuuskatsauksessa selvisi, että suorituskyvyn kannalta tärkeintä olisi mitata kontaktien määrää siinä, missä kontaktien laatu ja prosessin sujuvuus toimivat täydentävinä mittauskohteina. Kyselytutkimuksen perusteella noin puolet vastaajaorganisaatioista mittasi toimintaansa ylipäätään. Käytetyt mittarit painottuivat asiakashankinnan laatuun. Toisen tavoitteen osalta mittaristo luotiin hyödyntämällä LUT:issa rakennetun SAKE-sovelluksen implementointiprosessia. Mittaristo kattaa sekä puhelimitse että kentällä tehdyn asiakashankinnan ja sähköisen markkinoinnin määrä- ja laatumittarit. Lisäksi on arvioitu, asiakashankinnan tavoitteet voidaan jalkauttaa käytännön työhön. Kirjallisuuskatsauksen avulla tehdyt johtopäätökset toimivat ohjenuorana, kun pohditaan vastaavan toiminnan mittaamista. Tehtyä mittaristoa ei ole tarkoituksenmukaista soveltaa muualla sellaisenaan, vaan mittaristo tulee aina sovittaa kohdeorganisaatioon. Kyselytutkimuksen tuloksia ei voida pienen vastaajamäärän takia yleistää järjestökenttään.
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Global trends associated with development of information technology, globalization, industrial and economic changes are influencing on company and customer domains and thus transforming company-customer relationship. The company centric paradigm with a strong product focus shifts to a customer oriented one with a strong emphasis on customer collaboration. As a result, the customer role changes from a passive observer to an active player. Moreover, global trends contribute to transformation of competitive environment making it tougher and simplifying an access to resources previously considered as unique. All that factors push the companies towards cooperation with customers in order to identify unarticulated needs and finding the best possible solution to existing customer problems. The Master’s Thesis is done for Outotec (Lappeenranta) which considers extension of dewatering business in Russian coal market. Research aims to identify key features of coal preparation and dewatering of fine coal and tailings in Russian preparation plants; analyze the state of Russian coal market and evaluate market potential for Outotec dewatering solutions. The study has a qualitative nature and implements an action research methodology that involves both creation of knowledge and introduction of changes into the system. The base for taking actions is formed by theoretical framework that targets on describing company - customer interaction and has selected co-creation as the most appropriate method of customer involvement. The integration of co-creation approach into an action research cycle allows not only fulfilling the research objectives but also facilitates organizational learning and intraorganizational collaboration, assists in establishing customer contacts and making the first steps into the market, bringing new joint projects to the company and opening real business opportunities.
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Online sexual solicitation (solicitation) of youth has received widespread media and research attention during the last decade. The prevalence rates of youth who have experienced solicitation or solicitation attempts vary between studies depending on the methodology used (e.g., whether youth or adults are the target study group). In studies focusing on youth victims, the prevalence of solicitation attempts made by adults during the past year is typically reported to be between 5 and 9%. Adults who solicit youth online have been found to use deception and other manipulative behaviors to gain access to sexual activities with youth. However, previous studies have lacked a control group of adults who solicit other adults online. Without this comparison, one could argue that deceiving others online about one’s identity, and engaging in manipulative behaviors, is an inherent part of most online sexual interactions with strangers. Additionally, little is known about the associations between manipulative behaviors and the solicitation outcomes. In research concerning offline sexual behaviors, it has been noted that situational factors, such as sexual arousal, may alter both sexual interest and behavior. The effects of situational factors on online sexual behaviors have been less extensively studied (especially so with a quantitative approach); no studies have to date focused on adults’ solicitation of youth. Investigating the role of a lowered sexual age preference and the role of situational factors in the soliciting adults could be an important step in order to receive deeper knowledge of the role of traits and states in the context of solicitation. Additionally, there is a lack of knowledge of the effect of the age of the youth. Although previous studies on solicitation has found that older youth, compared with younger youth and children, are more often solicited, the possible reasons for this have not been investigated. Are adults who solicit youth affected by legal deterrence (through the legal age of consent), is it because older youth are more available online, or are the adults’ age preferences merely a product of a normally distributed age preference in the population? The purpose of the present thesis was fivefold: 1) to obtain an estimate of the frequency of adults’ solicitation of youth as self-reported and observed in actual behavior; 2) to explore whether the legal age of consent (LAC) affects solicitation frequency, or whether a normally distributed sexual age preference more accurately describe the proportion of solicited youth of different ages; 3) to investigate the associations of both traits (e.g., lower sexual age preference) and states (immediate situational factors, such as alcohol intoxication), and the solicitation target; 4) to explore whether adults who solicit youth and adults who solicit adults are equally deceitful and manipulative online, and whether the different solicitation outcomes are as common in both groups; and 5) to investigate whether the deceitful and manipulative behaviors engaged in had different associations with the solicitation outcomes depending on the age of the solicited. In the survey study, a convenience sample of 1393 adult participants (aged 18 years or older) self-reported any online communication with strangers during the past year. Of these, 56% (776 respondents) reported that they had solicited or attempted to solicit at least one stranger. Of the respondents, 453 (58.4%) were men, and 323 (41.6%) were women. Participants with only adult contacts (18 years or older) constituted the majority (640 respondents). In contrast, 136 individuals reported a youth contact (a 13 year old or younger, or a 14 to 17-year old). Approximately half of the participants were men in the adult contact group, while 75% of the participants were men in the youth contact group. Approximately 60% of the participants with youth contacts were recruited from two websites associated with a pedophilic sexual interest. In an online quasi-experimental study, with researchers impersonating youth of different ages (10–18 year olds) in chat rooms, 251 online conversations with chat room visitors made up the entire sample. All chat room visitors alleged to be men. The self-reported frequency of having solicited youth (0–17-year olds) during the past year was approximately 10% in our sample of adults who reported communicating with any strangers online. When we observed this behavior in chat rooms, we found that approximately 30% of the chat room visitors who believed they interacted with a 10 to 14 year old attempted to solicit the youth. We found that solicitation attempts increased equally much when increasing the age of the impersonated youth from 14 to 16, as from 16 to 18. Thus, we concluded that a normally distributed age preference in the population was a more plausible explanation to the effect of the age of the solicited, rather than the LAC (here; 15 and 16). If the chat room visitors would have been deterred only by the LAC, we would have expected that the change in amount of solicitation attempts from an illegal age group to a legal age group would have been significantly stronger than changes between age groups within illegal-illegal and legal-legal groups. Our subsample of survey participants from the pedophilia-related websites expectedly reported that they had solicited youth more often in comparison to the sample gathered through general (i.e., not associated with any particular sexual preference) websites. We also found that participants with a youth contact reported higher levels of sexual arousal and shame before the sexual interaction with their online contact, compared with participants with an adult contact. Additionally, the participants with youth contacts who reported consumption of child- and adolescent pornography also reported being more sexually aroused before the interaction, compared to the participants with youth contacts who did not report consumption of these kinds of pornography. We also found clear indications that the online sexual interaction had an alleviatory effect on reported levels of sadness, boredom and stress, independent of the age of the contact. Generally, the participants with youth and adult contacts reported deceiving their contacts as often and suggesting keeping the communication a secret from someone as often. Participants with a youth contact, however, reported using more persuasion techniques for online sexual purposes or for the purpose of an offline meeting, compared to those with an adult contact. In the chat rooms, we found that more indirect ways of future sexual communication (e.g., continuing chatting) was suggested by the chat room visitors that were under the assumption of interacting with youth aged 10 to 14, compared with more direct means (e.g., meeting offline). Survey participants with youth contacts who had used deception, suggested keeping the interactions a secret, and/or persuaded their contact by appealing to the contacts feelings of love and attachment for the participant had also more often engaged in cybersex with the contact. No other manipulative behaviors were associated with the other investigated solicitation outcomes (receiving a sexual picture, meeting offline, and engaging in sexual contact offline) within this group of participants. However, using deception, suggesting secrecy and using persuasion was also positively associated with certain solicitation outcomes within participants with an adult contact. In summary, adults’ solicitation of youth is much more frequent when observed in chat rooms than self-reported. Additionally, an underlying lowered sexual age preference seems to be a motivating factor on a group level in adults who solicit youth. We concluded that directed prevention efforts should be made on pedophiliarelated websites. Additionally, the role of situational factors, especially sexual arousal in persons with a pedo- or hebephilic sexual interest should be investigated further in the context of online sexual solicitation.
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Decrease in microbial contacts in affluent societies is considered to lie behind the rise in allergic and other chronic inflammatory diseases during the last decades. Indeed, deviations in the intestinal microbiota composition and diversity have been associated with several diseases, such as atopic eczema. However, there is no consensus yet on what would constitute a beneficial or harmful microbiota. The aim of this thesis was to study the microbiota development in healthy infants and to characterize intestinal microbiota signatures associated with disease status and severity in infants with atopic eczema. The methodological aim was to compare and optimize methods for DNA extraction from fecal samples to be used in high-throughput microbiota analyses. It was confirmed that the most critical step in successful microbial DNA extraction from fecal samples is the mechanical cell lysis procedure. Based on this finding, an efficient semi-automated extraction process was developed that can be scaled for use in high-throughput platforms such as phylogenetic microarray used in this series of studies. By analyzing a longitudinal motherchild cohort for 3 years it was observed that the microbiota development is a gradual process, where some bacterial groups reach the degree of adult-type pattern earlier than others. During the breast-feeding period, the microbiota appeared to be relatively simple, while major diversification was found to start during the weaning process. By the age of 3 years, the child’s microbiota composition started to resemble that of an adult, but the bacterial diversity has still not reached the full diversity, indicating that the microbiota maturation extends beyond this age. In addition, at three years of age, the child’s microbiota was more similar to mother’s microbiota than to microbiota of nonrelated women.In infants with atopic eczema, a high total microbiota diversity and abundance of butyrate-producing bacteria was found to correlate with mild symptoms at 6 months. At 18 months, infants with mild eczema had significantly higher microbiota diversity and aberrant microbiota composition when compared to healthy controls at the same age. In conclusion, the comprehensive phylogenetic microarray analysis of early life microbiota shows the synergetic effect of vertical transmission and shared environment on the intestinal microbiota development. By the age of three years, the compositional development of intestinal microbiota is close to adult level, but the microbiota diversification continues beyond this age. In addition, specific microbiota signatures are associated with the existence and severity of atopic eczema and intestinal microbiota seems to have a role in alleviating the symptoms of this disease.
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Potentiometric sensors are very attractive tools for chemical analysis because of their simplicity, low power consumption and low cost. They are extensively used in clinical diagnostics and in environmental monitoring. Modern applications of both fields require improvements in the conventional construction and in the performance of the potentiometric sensors, as the trends are towards portable, on-site diagnostics and autonomous sensing in remote locations. The aim of this PhD work was to improve some of the sensor properties that currently hamper the implementation of the potentiometric sensors in modern applications. The first part of the work was concentrated on the development of a solid-state reference electrode (RE) compatible with already existing solid-contact ion-selective electrodes (ISE), both of which are needed for all-solid-state potentiometric sensing systems. A poly(vinyl chloride) membrane doped with a moderately lipophilic salt, tetrabutylammonium-tetrabutylborate (TBA-TBB), was found to show a satisfactory stability of potential in sample solutions with different concentrations. Its response time was nevertheless slow, as it required several minutes to reach the equilibrium. The TBA-TBB membrane RE worked well together with solid-state ISEs in several different situations and on different substrates enabling a miniature design. Solid contacts (SC) that mediate the ion-to-electron transduction are crucial components of well-functioning potentiometric sensors. This transduction process converting the ionic conduction of an ion-selective membrane to the electronic conduction in the circuit was studied with the help of electrochemical impedance spectroscopy (EIS). The solid contacts studied were (i) the conducting polymer (CP) poly(3,4-ethylienedioxythiophene) (PEDOT) and (ii) a carbon cloth having a high surface area. The PEDOT films were doped with a large immobile anion poly(styrene sulfonate) (PSS-) or with a small mobile anion Cl-. As could be expected, the studied PEDOT solid-contact mediated the ion-toelectron transduction more efficiently than the bare glassy carbon substrate, onto which they were electropolymerized, while the impedance of the PEDOT films depended on the mobility of the doping ion and on the ions in the electrolyte. The carbon cloth was found to be an even more effective ion-to-electron transducer than the PEDOT films and it also proved to work as a combined electrical conductor and solid contact when covered with an ion-selective membrane or with a TBA-TBB-based reference membrane. The last part of the work was focused on improving the reproducibility and the potential stability of the SC-ISEs, a problem that culminates to the stability of the standard potential E°. It was proven that the E° of a SC-ISE with a conducting polymer as a solid contact could be adjusted by reducing or oxidizing the CP solid contact by applying current pulses or a potential to it, as the redox state of the CP solid-contact influences the overall potential of the ISE. The slope and thus the analytical performance of the SC-ISEs were retained despite the adjustment of the E°. The shortcircuiting of the SC-ISE with a conventional large-capacitance RE was found to be a feasible instrument-free method to control the E°. With this method, the driving force for the oxidation/reduction of the CP was the potential difference between the RE and the SC-ISE, and the position of the adjusted potential could be controlled by choosing a suitable concentration for the short-circuiting electrolyte. The piece-to-piece reproducibility of the adjusted potential was promising, and the day-today reproducibility for a specific sensor was excellent. The instrumentfree approach to control the E° is very attractive considering practical applications.
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Recent Storms in Nordic countries were a reason of long power outages in huge territories. After these disasters distribution networks' operators faced with a problem how to provide adequate quality of supply in such situation. The decision of utilization cable lines rather than overhead lines were made, which brings new features to distribution networks. The main idea of this work is a complex analysis of medium voltage distribution networks with long cable lines. High value of cable’s specific capacitance and length of lines determine such problems as: high values of earth fault currents, excessive amount of reactive power flow from distribution to transmission network, possibility of a high voltage level at the receiving end of cable feeders. However the core tasks was to estimate functional ability of the earth fault protection and the possibility to utilize simplified formulas for operating setting calculations in this network. In order to provide justify solution or evaluation of mentioned above problems corresponding calculations were made and in order to analyze behavior of relay protection principles PSCAD model of the examined network have been created. Evaluation of the voltage rise in the end of a cable line have educed absence of a dangerous increase in a voltage level, while excessive value of reactive power can be a reason of final penalty according to the Finish regulations. It was proved and calculated that for this networks compensation of earth fault currents should be implemented. In PSCAD models of the electrical grid with isolated neutral, central compensation and hybrid compensation were created. For the network with hybrid compensation methodology which allows to select number and rated power of distributed arc suppression coils have been offered. Based on the obtained results from experiments it was determined that in order to guarantee selective and reliable operation of the relay protection should be utilized hybrid compensation with connection of high-ohmic resistor. Directional and admittance based relay protection were tested under these conditions and advantageous of the novel protection were revealed. However, for electrical grids with extensive cabling necessity of a complex approach to the relay protection were explained and illustrated. Thus, in order to organize reliable earth fault protection is recommended to utilize both intermittent and conventional relay protection with operational settings calculated by the use of simplified formulas.
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Tutkielman aiheena on kieli ja tyyli Jöns Budden latinasta muinaisruotsiksi kääntämissä teksteissä. Tarkoituksena on tutkia, millaisia tekstejä Budde käänsi ja missä tarkoituksessa. Lisäksi tutkin kielikontakteja latinaan ja saksaan sekä Buddea henkilönä hänen tuotantonsa valossa. Arvioin myös aiempien Buddeen liittyvien hypoteesien paikkansapitävyyttä. Materiaali käsittää kaikki tekstit, joiden yleisesti oletetaan olevan Budden kääntämiä. Osa on anonyymejä, mutta niiden yhteys Buddeen on erittäin todennäköinen. Aineisto käsittää noin 1350 sivua painetuissa editioissa. Tutkimus on materiaalilähtöistä: tarkan tekstinluvun ja teksti-interpretaation kautta olen kiinnittänyt huomioni erilaisiin etupäässä tyylillisiin seikkoihin, joita kommentoin ottaen huomioon kulttuurihistoriallisen kontekstin. Tutkimus kohdistuu kielenkäyttöön tietyssä konkreettisessa materiaalissa eli tarkastelun kohteina ovat parole ja synkronia ensisijaisemmin kuin diakronia ja langue eli kieli systeeminä ja resurssina. Metodina on siten filologinen teksti-interpretaatio, ja tutkimus on kommentaari Budden teksteihin. Keskeinen tulos on, että Budde on tietoinen stilisti, joka käyttää kieliopin ja stilistiikan keinoja sisällöllisten asioiden painottamiseen ja dramatisointiin. Budden tyyli-ihanteilla on suureksi osaksi esikuvia latinassa, mutta Budde ei noudata niitä orjallisen sokeasti, vaan on itsenäinen alkuteksteihin nähden. Toinen merkittävä tulos liittyy Budden kääntämien Raamatun kirjojen tarkoitukseen. Käsitykseni mukaan niitä ei ole tarkoitettu luettaviksi sellaisenaan, vaan apuvälineiksi luettaessa varsinaista pyhää kirjaa eli Vulgataa latinaksi. Tekstien tekijyyteen liittyvät aiemmat hypoteesit saavat tukea tutkimuksestani, kun taas Budden aristokraattisiin yhteyksiin ja hänen mahdollisiin opintoihinsa Saksassa liittyvät hypoteesit osoittautuvat liian rohkeiksi ottaen huomioon säilyneiden lähteiden niukkuuden.
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Metastasis is the main cause of death among cancer patients. In order to initiate the metastatic cascade cancer cells have to undergo epithelial-to-mesenchymal transition (EMT). In EMT epithelial cells lose their cell-cell and cell-extracellular matrix (ECM) contacts and become more motile. The expression of the transcription factor Slug and of the mesenchymal intermediate filament vimentin is induced during EMT. Vimentin is often overexpressed in malignant epithelial cancers but the functional role of vimentin remains incompletely understood. In addition, kinases such as AKT and ERK are known to be involved in the regulation of EMT and cancer cell motility but the mechanisms underlining their functions are often unclear. Integrins are heterodimeric receptors that attach cells to the surrounding tissue and participate in regulating cell migration and invasion. Changes in integrin activity are linked to increased cell motility and further cancer metastasis. The aim for my PhD studies was to investigate the role of cellular signalling pathways and vimentin in the regulation of cancer cell motility and EMT. Our results revealed that in prostate cancer the downregulation of AKT1 and AKT2, but not AKT3, induces activation of cell surface 1-integrins leading to enhanced cell adhesion, migration and invasion. In addition, our findings demonstrated a reciprocal regulatory interaction between vimentin and ERK2 facilitating ERK-mediated phosphorylation of Slug at serine-87 (S87) in breast cancer. Surprisingly, Slug S87 phosphorylation is dispensable for E-cadherin repression but essential for the induction of vimentin and Axl expression in early onset of EMT. Our findings reveal previously unknown mechanistic information of how prostate and breast cancer cell motility and disease progression is regulated
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As unregistered grassroots charities do not appear in official statistics in China, they tend to remain unnoticed by scholars. Also as they operate unofficially and avoid publicity, their work is usually not reported by the media. In this research I explore the grassroots charity activity of one pop music fan club from the viewpoint of trust as a sociological concept. I will also establish the general situation on charity in China. By using textual analysis on internet blogs and discussion forums I map the charity project from the discussion of the original idea to the execution and follow up phase. I study the roles the fan club members assume during the project as anonymous participants of internet conversations, as well as concrete active charity volunteers outside of the virtual world. I establish parties, other than the fan club, which are involved in the charity project. Interviews with one of the participant of the project in 2010, 2014 and 2015 bring valuable additional information and help in distributing the questionnaire survey. A quantitative questionnaire survey was distributed among the fan club members to get more detailed information on the motives and attitudes towards official and unofficial charity in China. Because of the inequality in China, the rural minority areas do not have similar educational opportunities as the mostly majority inhabited urban areas, even though the country officially has a nine year compulsory education. Grassroots charities can operate in relative freedom taking some of the government’s burden of social responsibilities if they are not criticizing the authorities. The problem with grassroots charity seems to be lack of sustainability. The lack of trust for authorities and official charities was the reason why the Jane Zhang fan club decided to conduct a charity case unofficially. As a group of people previously unknown to each other, they managed to build mutual trust to carry out the project transparently and successfully, though not sustainably. The internet has provided a new and effective platform for unofficial grassroots charities, who choose not to co-operate with official organisations. On grassroots level charities can have the transparency and trust that lack from official charities. I suggest, that interviewing the real persons behind the internet aliases and finding out what happened outside the discussion forums, would bring a more detailed and outspoken description of the project concerning of the contacts with the local authorities. Also travelling to the site and communicating with the local people in the village would establish how they have experienced the project.
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The objective of this study is to understand why virtual knowledge workers conduct autonomous tasks and interdependent problem solving tasks on virtual platforms. The study is qualitative case study including three case organizations that tap the knowledge of expert networks, and utilize virtual platforms in the work processes. Research data includes 15 interviews, that is, five experts from each case company. According to the findings there are some specific characteristics in motivation to work on tasks on online platforms. Autonomy, self-improvement, meaningful tasks, knowledge sharing, time management, variety of contacts, and variety of tasks, and projects motivate virtual knowledge workers. Factors that may enhance individuals’ engagement to work on tasks are trust, security of continuous task flow and income, feedback, meaningful tasks and tasks that contribute to self-improvement, flexibility and effectiveness in time management, and virtual tools that support social interaction. The results also indicate that there are some differences in individuals’ motivation based on the tasks’ nature. That is, knowledge sharing and variety of contacts motivated experts who worked on interdependent problem solving tasks. Then again, autonomy and variety of tasks motivated experts who worked on autonomous tasks.
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The study approaches student travel from the perspective of postmodern consumption. The background is in the observation that the student travel market has a vast potential, but it is not necessarily capitalized upon to the extent it could. This might partly have to do with the peculiarities of postmodernity: consumption is characterized by unpredictability and abstract motives. The research questions are built around what constitutes student travel consumption and how can students be categorized according to motivation, behaviour and values. Also identity and expressiveness are present and it is evaluated, if travel services facilitate these background is the observation that the student travel market has a vast potential, but it is not necessarily capitalized upon to the extent it could be. This might partly have to do with the peculiarities of postmodernity: consumption is characterized by unpredictability and abstract motives. The research questions are built around what constitutes student travel consumption and how can students be categorized according to motivation, behaviour and values. Also identity and expressiveness are present and it is evaluated whether travel services facilitate these constructs. The topic is approached by discovering the key concepts such as self-identity. This was done in order to create survey questions that reflect the underlying theories. The survey was sent to chosen student groups of Turku School of Economics. The data was analyzed using statistical methods, mainly principal component analysis, in order to categorize students’ motives and behaviour into distinct profiles. The findings indicate that students have a high level of awareness in their travel consumption choices. Travel services seem to facilitate identity and lifestyle expressiveness, one central dimension of postmodernity. Psychographics such as motivation seem to work well as a segmentation criteria when it comes to the student traveler market. Travel offers students an opportunity for relaxation, escape, enjoyment and gaining new experiences and social contacts. Furthermore, the enjoyment of the travel experience extends to the pre- and post-trip time.