897 resultados para REGENERATIVE NICHE


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Spermatogenesis, i.e sperm production in the seminiferous tubules of the testis, is a complex process that takes over one month to complete. Life-long ability of sperm production ultimately lies in a small population of undifferentiated cells, called spermatogonial stem cells (SSCs). These cells give rise to differentiating spermatogonia, which are committed to mature into spermatozoa. SSCs represent a heterogeneous population of cells and many aspects of their basic biology are still unknown. Understanding the mechanisms behind the cell fate decision of these cells is important to gain more insights into the causes of infertility and testis cancer. In addition, an interesting new aspect is the use of testis-derived stem cells in regenerative medicine. Our data demonstrated that adult mouse testis houses a population of Nanog-expressing spermatogonia. Based on mRNA and protein analysis these cells are enriched in stage XII of the mouse seminiferous epithelial cycle. The cells derived from this stage have the highest capacity to give rise to ES cell-like cells which express Oct4 and Nanog. These cells are under tight non- GDNF regulation but their fate can be dictated by activating p21 signalling. Comparative studies suggested that these cells are regulated like ES cells. Taken together these data imply that pluripotent cells are present in the adult mammalian testis. CIP2A (cancerous inhibitor of PP2A) has been associated with tumour aggressiveness and poor prognosis. In the testis it is expressed by the descendants of stem cells, i.e. the spermatogonial progenitor cells. Our data suggest that CIP2A acts upstream of PLZF and is needed for quantitatively normal spermatogenesis. Classification of CIP2A as a cancer/testis gene makes it an attractive target for cancer therapy. Study on the CIP2A deficient mouse model demonstrates that systemic inhibition of CIP2A does not severely interfere with growth and development or tissue or organ function, except for the spermatogenic output. These data demonstrate that CIP2A is required for quantitatively normal spermatogenesis. Hedgehog (Hh) signalling is involved in the development and maintenance of many different tissues and organs. According to our data, Hh signalling is active at many different levels during rat spermatogenesis: in spermatogonia, spermatocytes and late elongating spermatids. Localization of Suppressor of Fused (SuFu), the negative regulator of the pathway, specifically in early elongating spermatids suggests that Hh signalling needs to be shut down in these cells. Introduction of Hh signalling inhibitor resulted in an increase in germ cell apoptosis. Follicle-stimulating hormone (FSH) and inhibition of receptor tyrosine kinases resulted in down-regulation of Hh signalling. These data show that Hh signalling is under endocrine and paracrine control and it promotes germ cell survival.

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Pluripotent cells have the potential to differentiate into all somatic cell types. As the adult human body is unable to regenerate various tissues, pluripotent cells provide an attractive source for regenerative medicine. Human embryonic stem cells (hESCs) can be isolated from blastocyst stage embryos and cultured in the laboratory environment. However, their use in regenerative medicine is restricted due to problems with immunosuppression by the host and ethical legislation. Recently, a new source of pluripotent cells was established via the direct reprogramming of somatic cells. These human induced pluripotent stem cells (hiPSCs) enable the production of patient specific cell types. However, numerous challenges, such as efficient reprogramming, optimal culture, directed differentiation, genetic stability and tumor risk need to be solved before the launch of therapeutic applications. The main objective of this thesis was to understand the unique properties of human pluripotent stem cells. The specific aims were to identify novel factors involved in maintaining pluripotency, characterize the effects of low oxygen culture on hESCs, and determine the high resolution changes in hESCs and hiPSCs during culture and reprogramming. As a result, the previously uncharacterized protein L1TD1 was determined to be specific for pluripotent cells and essential for the maintenance of pluripotency. The low oxygen culture supported undifferentiated growth and affected expression of stem cell associated transcripts. High resolution screening of hESCs identified a number of culture induced copy number variations and loss of heterozygosity changes. Further, screening of hiPSCs revealed that reprogramming induces high resolution alterations. The results obtained in this thesis have important implications for stem cell and cancer biology and the therapeutic potential of pluripotent cells.

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The use of autologous platelet concentrates, represent a promising and innovator tools in the medicine and dentistry today. The goal is to accelerate hard and soft tissue healing. Among them, the platelet-rich plasma (PRP) is the main alternative for use in liquid form (injectable). These injectable form ofplatelet concentrates are often used in regenerative procedures and demonstrate good results. The aim of this study is to present an alternative to these platelet concentrates using the platelet-rich fibrin in liquid form (injectable) and its use with particulated bone graft materials in the polymerized form.

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Connectivity depends on rates of dispersal between communities. For marine soft-sediment communities continued small-scale dispersal as post-larvae and as adults can be equally important in maintaining community composition, as initial recruitment of substrate by pelagic larvae. In this thesis post-larval dispersal strategies of benthic invertebrates, as well as mechanisms by which communities are connected were investigated. Such knowledge on dispersal is scarce, due to the difficulties in actually measuring dispersal directly in nature, and dispersal has not previously been quantified in the Baltic Sea. Different trap-types were used underwater to capture dispersing invertebrates at different sites, while in parallel measuring waves and currents. Local community composition was found to change predictably under varying rates of dispersal and physical connectivity (waves and currents). This response was, however, dependent on dispersal-related traits of taxa. Actively dispersing taxa will be relatively better at maintaining their position, as they are not as dependent on hydrodynamic conditions for dispersal and will be less prone to be passively transported by currents. Taxa also dispersed in relative proportions that were distinctly different from resident community composition and a significant proportion (40 %) of taxa were found to lack a planktonic larval life-stage. Community assembly was re-started in a large-scale manipulative field experiment over one year across several sites, which revealed how patterns of community composition (α-, β- and λ-diversity) change depending on rates of dispersal. Results also demonstrated that in response to small-scale disturbance, initial recruitment was by nearby-dominant species after which other species arrived from successively further away. At later assembly time, the number of coexisting species increased beyond what was expected purely by local niche requirements (species sorting), transferring regional differences in community composition (β-diversity) to the local scale (α-diversity, mass effect). Findings of this thesis complement more theoretical studies in metacommunity ecology by demonstrating that understanding how and when individuals disperse relative to underlying environmental heterogeneity is key to interpreting how patterns of diversity change across different spatial scales. Such information from nature is critical when predicting responses to, for example, different types of disturbances or management actions in conservation.

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The dewatering of iron ore concentrates requires large capacity in addition to producing a cake with low moisture content. Such large processes are commonly energy intensive and means to lower the specific energy consumption are needed. Ceramic capillary action disc filters incorporate a novel filter medium enabling the harnessing of capillary action, which results in decreased energy consumption in comparison to traditional filtration technologies. As another benefit, the filter medium is mechanically and chemically more durable than, for example, filter cloths and can, thus, withstand harsh operating conditions and possible regeneration better than other types of filter media. In iron ore dewatering, the regeneration of the filter medium is done through a combination of several techniques: (1) backwashing, (2) ultrasonic cleaning, and (3) acid regeneration. Although it is commonly acknowledged that the filter medium is affected by slurry particles and extraneous compounds, published research, especially in the field of dewatering of mineral concentrates, is scarce. Whereas the regenerative effect of backwashing and ultrasound are more or less mechanical, regeneration with acids is based on chemistry. The chemistry behind the acid regeneration is, naturally, dissolution. The dissolution of iron oxide particles has been extensively studied over several decades but those studies may not necessarily be directly applicable in the regeneration of the filter medium which has undergone interactions with the slurry components. The aim of this thesis was to investigate if free particle dissolution indeed correlates with the regeneration of the filter medium. For this purpose, both free particle dissolution and dissolution of surface adhered particles were studied. The focus was on acidic dissolution of iron oxide particles and on the study of the ceramic filter medium used in the dewatering of iron ore concentrates. The free particle dissolution experiments show that the solubility of synthetic fine grained iron oxide particles in oxalic acid could be explained through linear models accounting for the effects of temperature and acid concentration, whereas the dissolution of a natural magnetite is not so easily explained by such models. In addition, the kinetic experiments performed both support and contradict the work of previous authors: the suitable kinetic model here supports previous research suggesting solid state reduction to be the reaction mechanism of hematite dissolution but the formation of a stable iron oxalate is not supported by the results of this research. Several other dissolution mechanisms have also been suggested for iron oxide dissolution in oxalic acid, indicating that the details of oxalate promoted reductive dissolution are not yet agreed and, in this respect, this research offers added value to the community. The results of the regeneration experiments with the ceramic filter media show that oxalic acid is highly effective in removing iron oxide particles from the surface of the filter medium. The dissolution of those particles did not, however, exhibit the expected behaviour, i.e. complete dissolution. The results of this thesis show that although the regeneration of the ceramic filter medium with acids incorporates the dissolution of slurry particles from the surface of the filter medium, the regeneration cannot be assessed purely based upon free particle dissolution. A steady state, dependent on temperature and on the acid concentration, was observed in the dissolution of particles from the surface even though the limit of solubility of free iron oxide particles had not been reached. Both the regeneration capacity and efficiency, with regards to the removal of iron oxide particles, was found to be temperature dependent, but was not affected by the acid concentration. This observation further suggests that the removal of the surface adhered particles does not follow the dissolution of free particles, which do exhibit a dependency on the acid concentration. In addition, changes in the permeability and in the pore structure of the filter medium were still observed after the bulk concentration of dissolved iron had reached a steady state. Consequently, the regeneration of the filter medium continued after the dissolution of particles from the surface had ceased. This observation suggests that internal changes take place at the final stages of regeneration. The regeneration process could, in theory, be divided into two, possibly overlapping, stages: (1) dissolution of surface-adhered particles, and (2) dissolution of extraneous compounds from within the pore structure. In addition to the fundamental knowledge generated during this thesis, tools to assess the effects of parameters on the regeneration of the ceramic filter medium are needed. It has become clear that the same tools used to estimate the dissolution of free particles cannot be used to estimate the regeneration of a filter medium unless only a robust characterisation of the order of regeneration efficiency is needed.

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Executive Summary Tuulivoimateollisuus on kasvanut erittäin voimakkaasti 2000-luvulla, ja viime vuonna asennettiin maailmanlaajuisesti ennätysmäärä noin 42 GW uutta tuulivoimakapasiteettia. Kumulatiivinen asennettu kapasiteetti oli vuoden 2011 lopussa noin 241 GW, josta eniten Euroopassa, sitten Kaakkois-Aasiassa, etenkin Kiinassa ja kolmanneksi suurimpana markkina-alueena oli USA. Kiinassa oli eniten asennettua tuulivoimaa, 26 % maailman tuulivoimasta, toisena oli USA, sitten Saksa, Espanja ja Intia. Suurin osa asennetusta koko maailman kapasiteetista on maatuulivoimaa (onshore), merituulivoimaa (offshore) oli asennettu vajaat 4 GW. Teollisuus työllisti arviolta yli 560000 henkilöä maailmanlaajuisesti ja liiketoiminnan arvo oli noin 52 Mrd. euroa (73 Mrd. USD). Tuuliturbiineja oli maailmalla toiminnassa noin 200000 ja niiden keskikoko oli 1,2 MW. Turbiinien koko on tasaisesti kasvanut ja nykyisin suurimmat kaupalliset turbiinit ovat 6-7 MW kokoluokassa. Suomessa oli vuoden 2012 lopussa asennettuna 163 turbiinia yhteisteholtaan 288 MW, joten olemme huomattavasti jäljessä useimpia muita EU maita tuulivoiman hyödyntämisessä. Tuulivoimamarkkinoiden ennakoidaan kasvavan keskimäärin noin 10 % vuosittain, jolloin vuonna 2020 maailmassa olisi asennettuna kapasiteettia noin 900 GW, josta offshore tuulivoimaa 75 GW. Tällöin tuulivoimalla tuotettaisiin noin 8 % sähköntuotannosta, kun arvio vuodelle 2012 on 2,26 %. Nopeinta kasvu olisi Kaakkois-Aasiassa ja Pohjois-Amerikassa, merituulivoimaa sen sijaan asennettaisiin eniten Eurooppaan. Suomen ilmasto- ja energiastrategin mukainen tavoite on 2,5 GW tuulivoimaa vuonna 2020. Moderni turbiini koostuu seuraavista pääkomponenteista: tornista, kolmilapaisesta roottorista, vaihteistosta, generaattorista, ja elektroniikasta. Turbiinien hinta vaihtelee projektista ja käytetystä tekniikasta johtuen, mutta tämän hetkisenä keskiarvona voidaan käyttää noin 1 MEUR / MW hintaa Euroopassa ja Pohjois-Amerikassa. Kiinassa hinta on vähintään yhden kolmasosan halvempi. Turbiinihintojen ennakoidaan halventuvan jo lähivuosien kuluessa jopa 30 % johtuen muun muassa suuruuden ekonomiasta ja kiristyvästä kilpailusta. Kun mukaan lasketaan kaikki kulut, kuten suunnittelu, luvat, turbiinin perustukset ja kaapeloinnit, tulee asennetulle turbiinille keskihinnaksi noin 1,5 MEUR. Merituulivoima voi olla kaksi kertaa kalliimpi investointi. Generaattoreina käytetään tyypillisesti nopeita tai keskinopeita induktio- (DFIG) tai kestomagneettigeneraattoreita (PMSG) ja yleisesti kolmivaihteisia vaihteistoja. Hidasnopeuksisen (PMSG) suoravetogeneraattorin (DD) käyttö on kuitenkin yleistymässä, sillä tällöin vältetään vika-alttiin vaihteiston käyttö. Korkea toimintaluotettavuus on erityisen tärkeä merituulivoimaloissa. Suurimmat 15 turbiinivalmistajaa toimittivat viime vuonna lähes 90 % maailman tuulivoimaloista. Suurin toimija on tanskalainen Vestas, jonka liikevaihto vuonna 2011 oli noin 6 Mrd euroa ja henkilöstöä yli 22000. Suurimpien valmistajien joukossa oli 7 kiinalaista toimijaa, jotka ovat kasvaneet nopeasti viime vuosina. Useimmat turbiinivalmistajat valmistavat joitakin strategisia komponentteja itse tai ostavat ne omaan konserniin kuuluvalta tytäryhtiöltä ja ostavat muut komponentit ja materiaalit sopimusvalmistajilta. Yhtiöiden valmistusstrategiat kuitenkin vaihtelevat ”tehdään kaikki itse” strategiasta pelkkään avainkomponenttien kokoonpanoon ja turbiinin kokonaistoimitukseen. Tyypillisesti turbiinivalmistajia palvelee vakiintunut joukko kansainväliseen toimintaan kyvykkäitä komponenttitoimittajia varatoimittajineen. Kaiken kaikkiaan sekä turbiini- että komponenttivalmistajien kesken on tapahtunut viime vuosikymmenen kuluessa konsolidoitumista. Valmistus on myös globalisoitunut eli avainkomponentit ja etenkin isot komponentit valmistetaan lähellä asiakasta. Toisaalta kiristynyt hintakilpailu on johtanut siihen, että yritykset ovat siirtäneet tuotantoa Kiinaan, joka nykyisin onkin suurin komponenttien valmistusmaa. Alan keskittyminen ja globalisoituminen tullee jatkumaan myös tulevaisuudessa. Suomessa on eri sektoreilta tuulivoiman huippuosaamista, mutta kokonaisvaltaista tuulivoimaklusteria meillä ei ole. Sellaisen rakentaminen tai rakentuminen vie aikaa ja edellyttäisi selkeän veturiyrityksen olemassaoloa. Tuuliturbiinien kokonaistoimituksista yleensä vastaava turbiinivalmistaja olisi luonteva veturiyritys, mutta kotimaiset valmistajat (Winwind ja Mervento) ovat kansainvälisesti pieniä, ja niiden markkina-asema on haastava. Lisäksi Winwind on ajautunut vakavaan taloudelliseen kriisiin (velkojat hakevat yhtiöltä saataviaan käräjäoikeudessa tammikuussa 2013). Kotimaisille turbiinivalmistajille, kuten muillekin tuulivoima-alan toimijoille olisi ensisijaista, että kotimaiset investoinnit käynnistyisivät täysipainoisesti. Tämä tarkoittaisi paitsi liiketoimintamahdollisuuksia, niin kumuloituvaa osaamista ja ennen kaikkea referenssejä kansainvälistä kilpailua silmälläpitäen. Suomalaisten turbiinivalmistajien kilpailukykyisin businessalue löytynee erityisosaamisesta, kuten esimerkiksi arktisesta tuulivoimasektorista. Mahdollisesti liittoutumalla tai jonkin johtavan turbiinivalmistajan tytäryrityksenä suomalainen niche markkinoille erikoistunut turbiinivalmistus voisi menestyä tulevaisuuden kovenevassa kilpailussa. Kilpailu päämarkkinoilla johtavien turbiinivalmistajien kanssa tuskin tuo menestystä, sillä näiden resurssit ja referenssit ovat ylivertaiset ja osaaminenkin osin suomalaisia edellä. Suomalaista huippuosaamista edustavat muun muassa ABB, The Switch, Vacon, Vaisala, Prysmian sekä Moventas. Yhtiöiden markkina-alue on globaali ja etenkin ABB:n ja Prysmianin resurssit mittavat. Yhtiöillä on edellytykset menestyä jatkossakin kansainvälisesti tuulivoimaliiketoiminnan komponenttien ja systeemien toimittajina. Moventaksen haasteena on yrityksen taloudellinen tilanne ja kilpailukyky markkinoilla (koko henkilöstö lomautetaan määräajaksi keväällä 2013). Muun muassa paperikonevalmistuksen ja meriteollisuuden johdolla Suomeen on syntynyt vahva konepajaosaaminen ja alihankintaverkosto. Esimerkiksi Holming, Componenta, Häkkinen Group ja Metso Foundries palvelevat jo tuulivoimateollisuutta. Osa yhtiöistä toimii kansainvälisesti ja niillä on mahdollisuus jatkossakin palvella tuulivoimateollisuutta, etenkin Suomessa ja lähialueilla. Komponenttitoimittajien ja alihankkijoiden kansainvälistymisen haasteina ovat muun muassa Suomen syrjäinen sijainti Euroopan päämarkkinoilta ja päämiesten jo osin vakiintuneet toimittajaverkostot. Tuulivoiman suunnittelu ja konsultointi sekä käyttö ja kunnossapito tarjoavat suomalaisille yhtiöille liiketoimintamahdollisuuksia Suomessa ja lähialueilla. Merkittävää uutta potentiaalia edustaa telakkateollisuus, ennen muuta STX Finland. STX konsernissa osataan erikoislaivojen tekeminen, konserni omistaa jo turbiinivalmistajan ja konsernin strategiana on tulla merkittäväksi tuulivoimatoimijaksi. Offshore perustukset ja tornit voisivat luontevasti olla omaa tuotantoa oman turbiinivalmistuksen, tuulipuistojen käytön ja kunnossapidon sekä erikoislaivojen ohella. STX Finlandilla olisi potentiaalia toimia suomalaisen tuulivoimateollisuuden veturiyrityksenä. Yhtiön rahoitustilanne ja kilpailukyky ovat kuitenkin tällä hetkellä haastavat. Rautaruukilla on potentiaalia toimittaa muun muassa ristikkorakenteisia torneja ja Parmalla hybriditorneja tuulivoimateollisuudelle. Suomalaisen tuulivoimaosaamisen ja työllisyyden kannalta keskeistä on, että Suomen ilmasto- ja energiastrategian mukaiset tuulivoimainvestoinnit saataisiin viipymättä käyntiin ja investointiympäristö säilyisi suotuisana ja ennustettavana. Tuulivoiman syöttötariffi tukee tuulivoiman taloudellista kannattavuutta lähitulevaisuudessa, mutta tuulivoimarakentamisen rajoituksia ja esteitä tulee myös merkittävästi purkaa tai lieventää.”Työpaikkoja syntyy niihin maihin joissa tuulivoimaa rakennetaan”. Tuulivoima työllistää paitsi suunnittelu- ja rakentamisvaiheessa, niin erityisesti laitosten 20-30 vuoden käyttö- ja kunnossapitoaikana. Teknologiateollisuuden (2012) positiivisen kasvuskenaarion mukaan tuulivoimateollisuus voisi työllistää jopa 25-30000 henkilöä vuonna 2020 nykyisten noin 2000 sijasta ja alan liikevaihto voisi olla jopa 12-14 Mrd. euroa. Tällainen kasvuskenaario sisältää kyllä merkittäviä epävarmuustekijöitä ja Tarastin (2012) selvitys arvioikin kasvun ja työllisyyden kehittyvän kasvuskenaariossakin maltillisemmin. Todennäköisimmät menestysmahdollisuudet ovat alalla jo merkittävässä asemassa olevilla resursseiltaan vahvoilla ja kansainvälisillä yrityksillä. Monialayritykset kestävät pelkästään tuulivoima-alaan keskittyneitä yrityksiä paremmin alalle tyypilliset liiketoiminnan vaihtelut. Erikoistuminen ja uudet radikaalit innovaatiot voivat kuitenkin tuoda tuulivoimaliiketoimintaan täysin uusia toimijoita tai muuttaa nykyisten yritysten kilpailuasetelmia. Kaupallisesti menestyviä uusia keksintöjä harvoin kuitenkaan syntyy ilman panostuksia. Ensiarvoisen tärkeää olisi määritellä kansallinen tahtotila, millä resurssein ja mihin tuulivoimateollisuuden sektoreihin halutaan panostaa, ja kohdentaa resurssit siten, että alan yrityksillä, tutkimuslaitoksilla ja muilla toimijoilla olisi parhaat edellytykset kehittää kilpailukykyisiä tuotteita, palveluita ja systeemeitä. Potentiaalisten uusien teknologioiden ja suomalaisten toimijoiden syvällisempi tarkastelu voisikin olla mielenkiintoisen jatkotutkimuksen aihe.

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This study examines the structure of the Russian Reflexive Marker ( ся/-сь) and offers a usage-based model building on Construction Grammar and a probabilistic view of linguistic structure. Traditionally, reflexive verbs are accounted for relative to non-reflexive verbs. These accounts assume that linguistic structures emerge as pairs. Furthermore, these accounts assume directionality where the semantics and structure of a reflexive verb can be derived from the non-reflexive verb. However, this directionality does not necessarily hold diachronically. Additionally, the semantics and the patterns associated with a particular reflexive verb are not always shared with the non-reflexive verb. Thus, a model is proposed that can accommodate the traditional pairs as well as for the possible deviations without postulating different systems. A random sample of 2000 instances marked with the Reflexive Marker was extracted from the Russian National Corpus and the sample used in this study contains 819 unique reflexive verbs. This study moves away from the traditional pair account and introduces the concept of Neighbor Verb. A neighbor verb exists for a reflexive verb if they share the same phonological form excluding the Reflexive Marker. It is claimed here that the Reflexive Marker constitutes a system in Russian and the relation between the reflexive and neighbor verbs constitutes a cross-paradigmatic relation. Furthermore, the relation between the reflexive and the neighbor verb is argued to be of symbolic connectivity rather than directionality. Effectively, the relation holding between particular instantiations can vary. The theoretical basis of the present study builds on this assumption. Several new variables are examined in order to systematically model variability of this symbolic connectivity, specifically the degree and strength of connectivity between items. In usage-based models, the lexicon does not constitute an unstructured list of items. Instead, items are assumed to be interconnected in a network. This interconnectedness is defined as Neighborhood in this study. Additionally, each verb carves its own niche within the Neighborhood and this interconnectedness is modeled through rhyme verbs constituting the degree of connectivity of a particular verb in the lexicon. The second component of the degree of connectivity concerns the status of a particular verb relative to its rhyme verbs. The connectivity within the neighborhood of a particular verb varies and this variability is quantified by using the Levenshtein distance. The second property of the lexical network is the strength of connectivity between items. Frequency of use has been one of the primary variables in functional linguistics used to probe this. In addition, a new variable called Constructional Entropy is introduced in this study building on information theory. It is a quantification of the amount of information carried by a particular reflexive verb in one or more argument constructions. The results of the lexical connectivity indicate that the reflexive verbs have statistically greater neighborhood distances than the neighbor verbs. This distributional property can be used to motivate the traditional observation that the reflexive verbs tend to have idiosyncratic properties. A set of argument constructions, generalizations over usage patterns, are proposed for the reflexive verbs in this study. In addition to the variables associated with the lexical connectivity, a number of variables proposed in the literature are explored and used as predictors in the model. The second part of this study introduces the use of a machine learning algorithm called Random Forests. The performance of the model indicates that it is capable, up to a degree, of disambiguating the proposed argument construction types of the Russian Reflexive Marker. Additionally, a global ranking of the predictors used in the model is offered. Finally, most construction grammars assume that argument construction form a network structure. A new method is proposed that establishes generalization over the argument constructions referred to as Linking Construction. In sum, this study explores the structural properties of the Russian Reflexive Marker and a new model is set forth that can accommodate both the traditional pairs and potential deviations from it in a principled manner.

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Human embryonic stem cells are pluripotent cells capable of renewing themselves and differentiating to specialized cell types. Because of their unique regenerative potential, pluripotent cells offer new opportunities for disease modeling, development of regenerative therapies, and treating diseases. Before pluripotent cells can be used in any therapeutic applications, there are numerous challenges to overcome. For instance, the key regulators of pluripotency need to be clarified. In addition, long term culture of pluripotent cells is associated with the accumulation of karyotypic abnormalities, which is a concern regarding the safe use of the cells for therapeutic purposes. The goal of the work presented in this thesis was to identify new factors involved in the maintenance of pluripotency, and to further characterize molecular mechanisms of selected candidate genes. Furthermore, we aimed to set up a new method for analyzing genomic integrity of pluripotent cells. The experimental design applied in this study involved a wide range of molecular biology, genome-wide, and computational techniques to study the pluripotency of stem cells and the functions of the target genes. In collaboration with instrument and reagent company Perkin Elmer, KaryoliteTM BoBsTM was implemented for detecting karyotypic changes of pluripotent cells. Novel genes were identified that are highly and specifically expressed in hES cells. Of these genes, L1TD1 and POLR3G were chosen for further investigation. The results revealed that both of these factors are vital for the maintenance of pluripotency and self-renewal of the hESCs. KaryoliteTM BoBsTM was validated as a novel method to detect karyotypic abnormalities in pluripotent stem cells. The results presented in this thesis offer significant new information on the regulatory networks associated with pluripotency. The results will facilitate in understanding developmental and cancer biology, as well as creating stem cell based applications. KaryoliteTM BoBsTM provides rapid, high-throughput, and cost-efficient tool for screening of human pluripotent cell cultures.

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There are several methods for inducing periodontal disease in animal models, being the bone defect one of the most reported. This study aimed to evaluate this model, through clinical, radiographic, tomographic and histological analyzes, thus providing standardized data for future regenerative works. Twelve dogs were subjected to the induction protocol. In a first surgical procedure, a mucoperiosteal flap was made on the buccal aspect of the right third and fourth premolars and a defect was produced exposing the furcation and mesial and distal roots, with dimensions: 5mm coronoapical, 5mm mesiodistal, and 3mm buccolingual. Periodontal ligament and cementum were curetted and the defect was filled with molding polyester, which was removed after 21 days on new surgical procedure. Clinical and radiographic examinations were performed after the two surgeries and before the collection of parts for dental tomography and histological analysis. All animals showed grade II furcation exposure in both teeth. Clinical attachment level increased after induction. Defect size did not change for coronoapical and buccolingual measurements, while mesiodistal size was significantly higher than at the time of defect production. Radiographic analysis showed decreased radiopacity and discontinuity of lamina dura in every tooth in the furcation area. The horizontal progression of the disease was evident in micro-computed tomography and defect content in the histological analysis. Therefore, it is concluded that this method promotes the induction of periodontal disease in dogs in a standardized way, thus being a good model for future work.

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TRIZ is one of the well-known tools, based on analytical methods for creative problem solving. This thesis suggests adapted version of contradiction matrix, a powerful tool of TRIZ and few principles based on concept of original TRIZ. It is believed that the proposed version would aid in problem solving, especially those encountered in chemical process industries with unit operations. In addition, this thesis would help fresh process engineers to recognize importance of various available methods for creative problem solving and learn TRIZ method of creative problem solving. This thesis work mainly provides idea on how to modify TRIZ based method according to ones requirements to fit in particular niche area and solve problems efficiently in creative way. Here in this case, the contradiction matrix developed is based on review of common problems encountered in chemical process industry, particularly in unit operations and resolutions are based on approaches used in past to handle those issues.

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Yandex is the dominant search engine in Russia, followed by the world leader Google. This study focuses on the performance differences between the two in search advertising in the context of tourism, by running two identical campaigns and measuring the KPI’s, such as CPA (cost-per-action), on both campaigns. Search engine advertising is a new and fast changing form of advertising, which should be studied frequently in order to keep up with the changes. Research was done as an experimental study in cooperation with a Finnish tourism company and the data is gathered from the clickstream and not from questionnaires, which is recommended method by the literature. The results of the study suggests that Yandex.Direct performed better in the selected niche and that the individual campaign planning for Yandex.Direct and Google AdWords is an important part of the optimization of search advertising in Russia.

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Poster at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014

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Three sampling sites were analysed in each of the following tropical regions: 1) northwestern São Paulo State, representing a disturbed region; 2) Bonito, Mato Grosso do Sul State, representing a hard water region; and 3) Ubatuba, northern costal region of São Paulo State, a well preserved tropical rainforest region. The hard water region had the highest mean values for macroalgal species richness (6.3) and diversity index (H' = 0.62). Northwest and rainforest regions had the highest percent cover values (22.5% and 17.0%, respectively). All sites in the northwest region had one or two dominant species (percent cover significantly higher than the remaining species), characterizing the niche pre-emption distribution pattern. The same pattern was found in two sites of the Atlantic rainforest. The hard water region had dominance of one species in two out of the three sites, but differently from the northwest region, niche overlap values were lower, evidencing a patch distribution. Competition for space was one of the main factors to explain spatial distribution. Overall, sites characterized by niche pre-emption had lower species richness, higher values for niche width and overlap, dominance index and percent cover of dominant species. In contrast, sites characterized by patch distribution had higher species richness and lower values for niche overlap and width, dominance index and percent cover.

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In some literature variations in photosynthetic rates are considered to be of little relevance for individual fitness. This depends among other things on how one defines fitness, i.e. if one takes strictly Darwinian fitness as seed production or if one needs to evaluate particular traits and consider plant establishment. It also matters if one takes the Darwinian "organism individual" as the central entity in evolution ("individual fitness") or the "species individual" in a modified "Structure of Evolutionary Theory" sensu Stephen Jay Gould. A phenotypically expressed trait like photosynthetic rate, even if intra- and interspecific differences may be small, can matter in habitat performance and niche acquisition. Light dependence curves (LCs) of photosynthetic rates are now readily measured under field conditions using miniaturized equipment of pulse amplitude modulated fluorometers. In contrast to actual momentary measurements of quantum yield of photosynthesis under actually prevailing ambient conditions, LC measurements reflect the expressed intrinsic capacity of photosynthesis. In this review we explore the power of LC measurements yielding cardinal points such as maximum apparent electron transport rate of photosystem II (ETRmax) and saturating photosynthetically active radiation (PARsat) in making intra- and interspecific comparisons of plant performance and synecological fingerprinting in ecophysiological studies across species, sites, habitats and ecosystems.

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Toxoplasma gondii and Trypanosoma cruzi are intracellular parasites which, as part of their life cycle, induce a potent cell-mediated immunity (CMI) maintained by Th1 lymphocytes and IFN-g. In both cases, induction of a strong CMI is thought to protect the host against rapid parasite multiplication and consequent pathology and lethality during the acute phase of infection. However, the parasitic infection is not eliminated by the immune system and the vertebrate host serves as a parasite reservoir. In contrast, Leishmania sp, which is a slow growing parasite, appears to evade induction of CMI during early stages of infection as a strategy for surviving in a hostile environment (i.e., inside the macrophages which are their obligatory niche in the vertebrate host). Recent reports show that the initiation of IL-12 synthesis by macrophages during these parasitic infections is a key event in regulating CMI and disease outcome. The studies reviewed here indicate that activation/inhibition of distinct signaling pathways and certain macrophage functions by intracellular protozoa are important events in inducing/modulating the immune response of their vertebrate hosts, allowing parasite and host survival and therefore maintaining parasite life cycles.