11 resultados para Embryo Culture Techniques

em Helda - Digital Repository of University of Helsinki


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Human-mediated movement of plants and plant products is now generally accepted to be the primary mode of introduction of plant pathogens. Species of the genus Phytophthora are commonly spread in this way and have caused severe epidemics in silviculture, horticulture as well as natural systems all over the world. The aims of the study were to gather information on the occurrence of Phytophthora spp. in Finnish nurseries, to produce information for risk assessments for these Phytophthora spp. by determining their host ranges and tolerance of cold temperatures, and to establish molecular means for their detection. Phytophthora cactorum was found to persist in natural waterbodies and results suggest that irrigation water might be a source of inoculum in nurseries. In addition to P. cactorum, isolates from ornamental nursery Rhododendron yielded three species new to Finland: P. ramorum, P. plurivora and P. pini. The only species with quarantine status, P. ramorum, was most adapted to growth in cold temperatures and able to persist in the nursery in spite of an annual sanitation protocol. Phytophthora plurivora and the closely related P. pini had more hosts among Nordic tree and plant species than P. ramorum and P. cactorum, and also had higher infectivity rates. All four species survived two weeks in -5 °C , and thus soil survival of these Phytophthoras in Finland is likely under current climatic conditions. The most common tree species in Finnish nurseries, Picea abies, was highly susceptible to P. plurivora and P. pini in pathogenicity trials. In a histological examination of P. plurivora in P. abies shoot tissues, fast necrotrophic growth was observed in nearly all tissues. The production of propagules in P. abies shoot tissue was only weakly indicated. In this study, a PCR DGGE technique was developed for simultaneous detection and identification of Phytophthora spp. It reliably detected Phytophthora in plant tissues and could discriminate most test species as well as indicate instances of multiple-species infections. It proved to be a useful detection and identification tool either applied alone or in concert with traditional isolation culture techniques. All of the introduced species of Phytophthora had properties that promote a high risk of establishment and spread in Finland. It is probable that more pathogens of this genus will be introduced and become established in Finland and other Nordic countries unless efficient phytosanitary control becomes standard practice in the international plant trade.

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Standards have been placed to regulate the microbial and preservative contents to assure that foods are safe to the consumer. In a case of a food-related disease outbreak, it is crucial to be able to detect and identify quickly and accurately the cause of the disease. In addition, for every day control of food microbial and preservative contents, the detection methods must be easily performed for numerous food samples. In this present study, quicker alternative methods were studied for identification of bacteria by DNA fingerprinting. A flow cytometry method was developed as an alternative to pulsed-field gel electrophoresis, the golden method . DNA fragment sizing by an ultrasensitive flow cytometer was able to discriminate species and strains in a reproducible and comparable manner to pulsed-field gel electrophoresis. This new method was hundreds times faster and 200,000 times more sensitive. Additionally, another DNA fingerprinting identification method was developed based on single-enzyme amplified fragment length polymorphism (SE-AFLP). This method allowed the differentiation of genera, species, and strains of pathogenic bacteria of Bacilli, Staphylococci, Yersinia, and Escherichia coli. These fingerprinting patterns obtained by SE-AFLP were simpler and easier to analyze than those by the traditional amplified fragment length polymorphism by double enzyme digestion. Nisin (E234) is added as a preservative to different types of foods, especially dairy products, around the world. Various detection methods exist for nisin, but they lack in sensitivity, speed or specificity. In this present study, a sensitive nisin-induced green fluorescent protein (GFPuv) bioassay was developed using the Lactococcus lactis two-component signal system NisRK and the nisin-inducible nisA promoter. The bioassay was extremely sensitive with detection limit of 10 pg/ml in culture supernatant. In addition, it was compatible for quantification from various food matrices, such as milk, salad dressings, processed cheese, liquid eggs, and canned tomatoes. Wine has good antimicrobial properties due to its alcohol concentration, low pH, and organic content and therefore often assumed to be microbially safe to consume. Another aim of this thesis was to study the microbiota of wines returned by customers complaining of food-poisoning symptoms. By partial 16S rRNA gene sequence analysis, ribotyping, and boar spermatozoa motility assay, it was identified that one of the wines contained a Bacillus simplex BAC91, which produced a heat-stable substance toxic to the mitochondria of sperm cells. The antibacterial activity of wine was tested on the vegetative cells and spores of B. simplex BAC91, B. cereus type strain ATCC 14579 and cereulide-producing B. cereus F4810/72. Although the vegetative cells and spores of B. simplex BAC91 were sensitive to the antimicrobial effects of wine, the spores of B. cereus strains ATCC 14579 and F4810/72 stayed viable for at least 4 months. According to these results, Bacillus spp., more specifically spores, can be a possible risk to the wine consumer.

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Poor pharmacokinetics is one of the reasons for the withdrawal of drug candidates from clinical trials. There is an urgent need for investigating in vitro ADME (absorption, distribution, metabolism and excretion) properties and recognising unsuitable drug candidates as early as possible in the drug development process. Current throughput of in vitro ADME profiling is insufficient because effective new synthesis techniques, such as drug design in silico and combinatorial synthesis, have vastly increased the number of drug candidates. Assay technologies for larger sets of compounds than are currently feasible are critically needed. The first part of this work focused on the evaluation of cocktail strategy in studies of drug permeability and metabolic stability. N-in-one liquid chromatography-tandem mass spectrometry (LC/MS/MS) methods were developed and validated for the multiple component analysis of samples in cocktail experiments. Together, cocktail dosing and LC/MS/MS were found to form an effective tool for increasing throughput. First, cocktail dosing, i.e. the use of a mixture of many test compounds, was applied in permeability experiments with Caco-2 cell culture, which is a widely used in vitro model for small intestinal absorption. A cocktail of 7-10 reference compounds was successfully evaluated for standardization and routine testing of the performance of Caco-2 cell cultures. Secondly, cocktail strategy was used in metabolic stability studies of drugs with UGT isoenzymes, which are one of the most important phase II drug metabolizing enzymes. The study confirmed that the determination of intrinsic clearance (Clint) as a cocktail of seven substrates is possible. The LC/MS/MS methods that were developed were fast and reliable for the quantitative analysis of a heterogenous set of drugs from Caco-2 permeability experiments and the set of glucuronides from in vitro stability experiments. The performance of a new ionization technique, atmospheric pressure photoionization (APPI), was evaluated through comparison with electrospray ionization (ESI), where both techniques were used for the analysis of Caco-2 samples. Like ESI, also APPI proved to be a reliable technique for the analysis of Caco-2 samples and even more flexible than ESI because of the wider dynamic linear range. The second part of the experimental study focused on metabolite profiling. Different mass spectrometric instruments and commercially available software tools were investigated for profiling metabolites in urine and hepatocyte samples. All the instruments tested (triple quadrupole, quadrupole time-of-flight, ion trap) exhibited some good and some bad features in searching for and identifying of expected and non-expected metabolites. Although, current profiling software is helpful, it is still insufficient. Thus a time-consuming largely manual approach is still required for metabolite profiling from complex biological matrices.

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Kirjallisuuden- ja kulttuurintutkimus on viimeisten kolmen vuosikymmenen aikana tullut yhä enenevässä määrin tietoiseksi tieteen ja taiteen suhteen monimutkaisesta luonteesta. Nykyään näiden kahden kulttuurin tutkimus muodostaa oman kenttänsä, jolla niiden suhdetta tarkastellaan ennen kaikkea dynaamisena vuorovaikutuksena, joka heijastaa kulttuurimme kieltä, arvoja ja ideologisia sisältöjä. Toisin kuin aiemmat näkemykset, jotka pitävät tiedettä ja taidetta toisilleen enemmän tai vähemmän vastakkaisina pyrkimyksinä, nykytutkimus lähtee oletuksesta, jonka mukaan ne ovat kulttuurillisesti rakentuneita diskursseja, jotka kohtaavat usein samankaltaisia todellisuuden mallintamiseen liittyviä ongelmia, vaikka niiden käyttämät metodit eroavatkin toisistaan. Väitöskirjani keskittyy yllä mainitun suhteen osa-alueista popularisoidun tietokirjallisuuden (muun muassa Paul Davies, James Gleick ja Richard Dawkins) käyttämän kielen ja luonnontieteistä ideoita ammentavan kaunokirjallisuuden (muun muassa Jeanette Winterson, Tom Stoppard ja Richard Powers) hyödyntämien keinojen tarkasteluun nojautuen yli 30 teoksen kattavaa aineistoa koskevaan tyylin ja teemojen tekstianalyysiin. Populaarin tietokirjallisuuden osalta tarkoituksenani on osoittaa, että sen käyttämä kieli rakentuu huomattavassa määrin sellaisille rakenteille, jotka tarjoavat mahdollisuuden esittää todellisuutta koskevia argumentteja mahdollisimman vakuuttavalla tavalla. Tässä tehtävässä monilla klassisen retoriikan määrittelemillä kuvioilla on tärkeä rooli, koska ne auttavat liittämään sanotun sisällön ja muodon tiukasti toisiinsa: retoristen kuvioiden käyttö ei näin ollen edusta pelkkää tyylikeinoa, vaan se myös usein kiteyttää argumenttien taustalla olevat tieteenfilosofiset olettamukset ja auttaa vakiinnuttamaan argumentoinnin logiikan. Koska monet aikaisemmin ilmestyneistä tutkimuksista ovat keskittyneet pelkästään metaforan rooliin tieteellisissä argumenteissa, tämä väitöskirja pyrkii laajentamaan tutkimuskenttää analysoimalla myös toisenlaisten kuvioiden käyttöä. Osoitan myös, että retoristen kuvioiden käyttö muodostaa yhtymäkohdan tieteellisiä ideoita hyödyntävään kaunokirjallisuuteen. Siinä missä popularisoitu tiede käyttää retoriikkaa vahvistaakseen sekä argumentatiivisia että kaunokirjallisia ominaisuuksiaan, kuvaa tällainen sanataide tiedettä tavoilla, jotka usein heijastelevat tietokirjallisuuden kielellisiä rakenteita. Toisaalta on myös mahdollista nähdä, miten kaunokirjallisuuden keinot heijastuvat popularisoidun tieteen kerrontatapoihin ja kieleen todistaen kahden kulttuurin dynaamisesta vuorovaikutuksesta. Nykyaikaisen populaaritieteen retoristen elementtien ja kaunokirjallisuuden keinojen vertailu näyttää lisäksi, kuinka tiede ja taide osallistuvat keskusteluun kulttuurimme tiettyjen peruskäsitteiden kuten identiteetin, tiedon ja ajan merkityksestä. Tällä tavoin on mahdollista nähdä, että molemmat ovat perustavanlaatuisia osia merkityksenantoprosessissa, jonka kautta niin tieteelliset ideat kuin ihmiselämän suuret kysymyksetkin saavat kulttuurillisesti rakentuneen merkityksensä.

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The present study provides a usage-based account of how three grammatical structures, declarative content clauses, interrogative content clause and as-predicative constructions, are used in academic research articles. These structures may be used in both knowledge claims and citations, and they often express evaluative meanings. Using the methodology of quantitative corpus linguistics, I investigate how the culture of the academic discipline influences the way in which these constructions are used in research articles. The study compares the rates of occurrence of these grammatical structures and investigates their co-occurrence patterns in articles representing four different disciplines (medicine, physics, law, and literary criticism). The analysis is based on a purpose-built 2-million-word corpus, which has been part-of-speech tagged. The analysis demonstrates that the use of these grammatical structures varies between disciplines, and further shows that the differences observed in the corpus data are linked with differences in the nature of knowledge and the patterns of enquiry. The constructions in focus tend to be more frequently used in the soft disciplines, law and literary criticism, where their co-occurrence patterns are also more varied. This reflects both the greater variety of topics discussed in these disciplines, and the higher frequency of references to statements made by other researchers. Knowledge-building in the soft fields normally requires a careful contextualisation of the arguments, giving rise to statements reporting earlier research employing the constructions in focus. In contrast, knowledgebuilding in the hard fields is typically a cumulative process, based on agreed-upon methods of analysis. This characteristic is reflected in the structure and contents of research reports, which offer fewer opportunities for using these constructions.

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Literary tale of A.M. Remizov (1900’s – 1920’s) The thesis is devoted to a detailed historical-literary description of a tale as a genre tradition in the creative work of Alexei Mikhailovich Remizov (1877-1957), one of the major Russian prose writers of the 20’s century. This very approach allows to specify the place and functional meaning of this genre in literary practice of the writer and to appeal to one of the key problems of the 20-21 century literature history – a specific of modernistic literature composition principle and a role of montage techniques in its formation. Remizov was working on tales during his whole life, though the most productive years of folklore studies fell to 1900’s – 1910’s. During this period he intensively studied folklore materials, narrated several hundreds of folk tales and in 1900’s – 1920’s published eight tale collections which played a significant role in the formation of stylistic and compositional principles of his prose of the 1910’s – 1920’s, especially montage techniques, which in its turn influenced the development of the narrative forms in the Russian post-revolutionary literature. At the same time a tale has specified not only poetics but also problematics of Remizov’s creative work, as when choosing folklore sources the writer always alluded to modern themes and relevant intellectual trends. The current research work, based on various archive materials and a wide spectrum of modern historical-literary data, complies four chapters with a consistent description of creation history, publication and critics’ reviews of Remizov’s tale collections and single tales contributing to his creative evolution characteristic. Furthermore, the work refers to composition and subject of the particular collections. On the whole it enables to follow up genre dynamics. The first chapter of the work is devoted to Posolon’ (Sunwise), the earliest tale collection of Remizov. The main feature of the collection is that its composition is oriented on the agrarian calendar and the subject – on the system of mythological views reflected in the Russian folklore. This very collection to a large extent corresponds to the writer’s views on the myth represented in Pis’mo v redaktsiyu (Letter to the Editor). The history of this manifesto appearing is analyzed in the second chapter. The incident which caused its forthcoming contributed to ‘legitimization’ of Remizov’s narrations as a relevant genre of modern literature and to upgrading the writer in professional hierarchy. The third chapter analyzes Remizov’s collections of 1900’s – early 1920’s, a result of Remizov’s scrupulous work with a specific tale material. He is acting here as a tale repertory researcher and in some cases as a collector as well. The means of such collections’ topical organization is not the myth but the hero of the tale. According to this principle single pieces are grouped into cycles, which then form complicated montage constructs. Texts themselves can be viewed as a sort of hyper-quotations, as they in fact entirely coincide with their original sources. Besides, collections usually have their own ideal patterns. In the fourth chapter a connection of Remizov’s creative work with folk fun culture and a tradition of the folklore noel story is being demonstrated on Zavetnyie skazy (Secret Tales) material. A consistent collections’ history creation analysis convinces us that the tale was a sort of laboratory in which main writer’s prose methods were being worked out.

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The theatrical censorship of the Third Reich considered the playwright's race and politics alongside the content of the drama. Given the political stigma of its "leftist" author, it is rather surprising that Hella Wuolijoki's Niskavuoren naiset opened in 1938 at the Staatliches Schauspielhaus in Hamburg. The play ran for fourteen performances before being closed by the Reichsdramaturgie, apparently at the instigation of Finnish critics. Yet this was not the end of the play's or its author's fortunes in the Third Reich, as the possibility of staging the play was raised several times over the next four years, coming to a close in 1942. Playing "Nordic" examines the ideological and theatrical background of this extended "cultural performance," as a means to reopening and reconstructing the work of the 1938 Die Frauen auf Niskavuori. Written by a Finnish, northern, "Nordic" author, and preoccupied with the dynamics of rural culture in an increasingly urbanized world, Niskavuoren naiset was understood in the Third Reich to illustrate and reinforce the racial, agri/cultural themes of Blut und Boden ("veri ja maa"). Playing "Nordic" examines this thematic relationship in three phases. The first phase uses archival materials to investigate the Reichsdramaturgie's understanding of the play and its author, and its ongoing discussion of Wuolijoki from 1937 to 1942. Play evaluator Sigmund Graff's description of Niskavuoren naiset as hamsunartig, or "Hamsun-esque," inspires the second phase of the dissertation, which first elaborates the meanings of Blut und Boden through a reading of contemporary "racial" theory and anthropology, and then assesses the representation of Finland within this discourse, one of the dominant cultural paradigms of the Third Reich. Imaging Finland for German audiences, the play stood among analogous, continued efforts to represent Finland and the rural life in the Third Reich, colored by Blut und Boden: art and agricultural exhibitions, essays and propaganda literature, mass demonstrations of the peasantry. This wider framework for the performance of "Finland" materializes the abstract or theoretical program of Blut und Boden in its everyday performed meanings; as such it provides the essential background for reading the Hamburg production of Die Frauen auf Niskavuori, which sustains the third and final phase. The German translation and the Hamburg photographic record are compared with the Helsinki premiere to assess the impact of Blut und Boden on the representation of Wuolijoki's play in the Third Reich. The journalistic critical response illuminates the effect that the dramatic complex of rural and racial values - generically identified as Bauerndrama in the Third Reich - had on the reception of the play; at the same time, both visual and critical documents also suggest possible moments of theatrical dissent in the Hamburg production. Playing "Nordic" undertakes a documentary and cultural reading of the changing theatrical meanings of Wuolijoki's Niskavuoren naiset as it crossed the frontier from Finland to the stage of the Third Reich. It also provides a model for the ways theatrical signification operates within a network of cultural and ideological meanings, suggesting the ideological work of theatrical production depends on, reinforces, and contests that tissue of values. Although Finnish criticism of Niskavuoren naiset has assumed the play's Blut und Boden resonance contributed to Wuolijoki's success in the Third Reich, this study shows a considerably more complex situation. This revealing production dramatizes the changing uses of plays in a politicized national and transnational context. As part of the framing of "Nordic" identity on the wider stage of the Third Reich, Die Frauen auf Niskavuori exemplifies the conjunction of concurrent - sometimes independent, sometimes interlocking - "racial" and national ideologies.

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The number of immigrant students in vocational education and training is steadily increasing in Finland. This poses challenges for teachers and schools. This research focuses on emerging questions of intercultural learning in the context of immigrant training, and on a method the Culture Laboratory that was developed in an attempt to respond to the challenges. The main methodological and theoretical framework lies in cultural-historical activity theory, developmental work research, and in the concepts of the intercultural and hybridity. The empirical material consists of videotaped recordings of discussions in the Culture Laboratory. The five main research questions focused on the strengths and limitations of the Culture Laboratory as a tool for intercultural learning, the significance of disturbances in it, the potential of suggestions for intercultural learning, paper as a mediating artifact , and the concept of intercultural space. The findings showed that the Culture Laboratory offered a solid background for developing intercultural learning. The disturbances manifested revealed a multitude of scripts and activities. It was also suggested that the structure of expansive learning could start from externalization instead of internalization. The suggestions the participants made opened up a hybrid learning space for intercultural development, and offered a good springboard for new ideas. Learning in Paperland posed both challenges and opportunities for immigrant students, and different paper trails emerged. Intercultural space in the Culture Laboratory was a developmental zone in which a hybrid process of observing, comparing, and creating took place. Key words: intercultural learning, immigrant training, cultural-historical activity theory, developmental work research,

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Failures in industrial organizations dealing with hazardous technologies can have widespread consequences for the safety of the workers and the general population. Psychology can have a major role in contributing to the safe and reliable operation of these technologies. Most current models of safety management in complex sociotechnical systems such as nuclear power plant maintenance are either non-contextual or based on an overly-rational image of an organization. Thus, they fail to grasp either the actual requirements of the work or the socially-constructed nature of the work in question. The general aim of the present study is to develop and test a methodology for contextual assessment of organizational culture in complex sociotechnical systems. This is done by demonstrating the findings that the application of the emerging methodology produces in the domain of maintenance of a nuclear power plant (NPP). The concepts of organizational culture and organizational core task (OCT) are operationalized and tested in the case studies. We argue that when the complexity of the work, technology and social environment is increased, the significance of the most implicit features of organizational culture as a means of coordinating the work and achieving safety and effectiveness of the activities also increases. For this reason a cultural perspective could provide additional insight into the problem of safety management. The present study aims to determine; (1) the elements of the organizational culture in complex sociotechnical systems; (2) the demands the maintenance task sets for the organizational culture; (3) how the current organizational culture at the case organizations supports the perception and fulfilment of the demands of the maintenance work; (4) the similarities and differences between the maintenance cultures at the case organizations, and (5) the necessary assessment of the organizational culture in complex sociotechnical systems. Three in-depth case studies were carried out at the maintenance units of three Nordic NPPs. The case studies employed an iterative and multimethod research strategy. The following methods were used: interviews, CULTURE-survey, seminars, document analysis and group work. Both cultural analysis and task modelling were carried out. The results indicate that organizational culture in complex sociotechnical systems can be characterised according to three qualitatively different elements: structure, internal integration and conceptions. All three of these elements of culture as well as their interrelations have to be considered in organizational assessments or important aspects of the organizational dynamics will be overlooked. On the basis of OCT modelling, the maintenance core task was defined as balancing between three critical demands: anticipating the condition of the plant and conducting preventive maintenance accordingly, reacting to unexpected technical faults and monitoring and reflecting on the effects of maintenance actions and the condition of the plant. The results indicate that safety was highly valued at all three plants, and in that sense they all had strong safety cultures. In other respects the cultural features were quite different, and thus the culturally-accepted means of maintaining high safety also differed. The handicraft nature of maintenance work was emphasised as a source of identity at the NPPs. Overall, the importance of safety was taken for granted, but the cultural norms concerning the appropriate means to guarantee it were little reflected. A sense of control, personal responsibility and organizational changes emerged as challenging issues at all the plants. The study shows that in complex sociotechnical systems it is both necessary and possible to analyse the safety and effectiveness of the organizational culture. Safety in complex sociotechnical systems cannot be understood or managed without understanding the demands of the organizational core task and managing the dynamics between the three elements of the organizational culture.