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  • Seppälä, Jukka (Helsingin yliopisto, 2009)
    To obtain data on phytoplankton dynamics with improved spatial and temporal resolution, and at reduced cost, traditional phytoplankton monitoring methods have been supplemented with optical approaches. In this thesis, I have explored various fluorescence-based techniques for detection of phytoplankton abundance, taxonomy and physiology in the Baltic Sea. In algal cultures used in this thesis, the availability of nitrogen and light conditions caused changes in pigmentation, and consequently in light absorption and fluorescence properties of cells. In the Baltic Sea, physical environmental factors (e.g. mixing depth, irradiance and temperature) and related seasonal succession in the phytoplankton community explained a large part of the seasonal variability in the magnitude and shape of Chlorophyll a (Chla)-specific absorption. The variability in Chla-specific fluorescence was related to the abundance of cyanobacteria, the size structure of the phytoplankton community, and absorption characteristics of phytoplankton. Cyanobacteria show very low Chla-specific fluorescence. In the presence of eukaryotic species, Chla fluorescence describes poorly cyanobacteria. During cyanobacterial bloom in the Baltic Sea, phycocyanin fluorescence explained large part of the variability in Chla concentrations. Thus, both Chla and phycocyanin fluorescence were required to predict Chla concentration. Phycobilins are major light harvesting pigments for cyanobacteria. In the open Baltic Sea, small picoplanktonic cyanobacteria were the main source of phycoerythrin fluorescence and absorption signal. Large filamentous cyanobacteria, forming harmful blooms, were the main source of the phycocyanin fluorescence signal and typically their biomass and phycocyanin fluorescence were linearly related. Using phycocyanin fluorescence, dynamics of cyanobacterial blooms can be detected at high spatial and seasonal resolution not possible with other methods. Various taxonomic phytoplankton pigment groups can be separated by spectral fluorescence. I compared multivariate calibration methods for the retrieval of phytoplankton biomass in different taxonomic groups. Partial least squares regression method gave the closest predictions for all taxonomic groups, and the accuracy was adequate for phytoplankton bloom detection. Variable fluorescence has been proposed as a tool to study the physiological state of phytoplankton. My results from the Baltic Sea emphasize that variable fluorescence alone cannot be used to detect nutrient limitation of phytoplankton. However, when combined with experiments with active nutrient manipulation, and other nutrient limitation indices, variable fluorescence provided valuable information on the physiological responses of the phytoplankton community. This thesis found a severe limitation of a commercial fast repetition rate fluorometer, which couldn t detect the variable fluorescence of phycoerythrin-lacking cyanobacteria. For these species, the Photosystem II absorption of blue light is very low, and fluorometer excitation light did not saturate Photosystem II during a measurement. This thesis encourages the use of various in vivo fluorescence methods for the detection of bulk phytoplankton biomass, biomass of cyanobacteria, chemotaxonomy of phytoplankton community, and phytoplankton physiology. Fluorescence methods can support traditional phytoplankton monitoring by providing continuous measurements of phytoplankton, and thereby strengthen the understanding of the links between biological, chemical and physical processes in aquatic ecosystems.
  • Isavnin, Alexey (Helsingin yliopisto, 2014)
    A lot of modern ground-based and space systems, such as navigation satellites, electric power grids, and telecommunication frameworks, can be affected by the changes in the near-Earth space environment, i.e., space weather. The main driver of the space weather is the Sun, which provides a supersonic flow of plasma, known as the solar wind. Coronal mass ejections (CMEs) are the most prominent feature of solar activity. They result from the eruptions on the Sun and propagate almost radially from it embedded into the solar wind. CMEs drive the strongest disturbances of the near-Earth space environment and cause the strongest geomagnetic storms when they encounter the magnetosphere of the Earth. A significant fraction of CMEs exhibit a specific configuration of twisted magnetic field lines, i.e., the flux rope configuration. The geoffectiveness of flux rope CMEs depends on their internal magnetic structure, morphological properties, speed, and the geometry of their propagation through the interplanetary space. In this thesis, the internal structure of flux rope CMEs and their three-dimensional evolution in the interplanetary space were investigated using the combination of white-light and extreme ultraviolet observations and in-situ measurements and modeling. The results of the analysis show that a typical flux rope CME consists of regions of physically different plasma with the flux rope occupying one of them. The methodology for studying the evolution of the individual flux rope in three-dimensional space is described. The presented technique is used to show that solar flux ropes experience significant deflections and rotations during their propagation from the Sun to the Earth's orbit that have to be taken into account for reliable space weather forecasting. These structures deflect predominantly towards the solar equatorial plane and their rotations are affected by the solar wind streams. It is discovered that 40% of the flux rope evolution happens after 30 solar radii. Flux-rope-like structures can also form in the magnetosphere during the periods of geomagnetic disturbances. They are generated in the magnetotail configurations with multiple reconnection sites and travel towards the Earth or away from it. Both types of these helical magnetic structures are addressed in this thesis as well. It is demonstrated that the properties of these structures help to get insight into the dynamics of the magnetosphere. The model of evolution of earthward-traveling flux ropes is presented, according to which they deteriorate and degrade into dipolarization fronts, another magnetic field configuration that is characteristic for geomagnetic disturbances. This thesis contributes both to the improvement of the flux rope analysis techniques as well as conducts a comprehensive analysis of solar and magnetospheric flux ropes and their evolution. The results of the research advance our understanding of the Sun-Earth coupling in one dynamical process and can be used for improving the space weather forecasting tools.
  • Wikström, Janne (2006)
    Studien handlar om en differentiering av användning och planering av periurbana eller rurbana grönområden. Det huvudsakliga syftet med avhandlingen är att analysera förhållandet mellan naturskyddare och friluftsaktörer med tanke på Noux skogsområde i Storhelsingfors. Också naturskydds- och friluftsorganisationers reaktioner på beslut som tagits inom miljöförvaltningen står i fokus. I arbetet ingår också en idéhistorisk beskrivning av utvecklingen av naturskydd och friluftsliv i moderna samhällen i allmänhet och Noux i synnerhet. Viktiga teoretiska influenser är Jonathan Murdochs och Terry Marsdens studier av differentiering samt Sverker Sörlins idéhistoriska verk om naturuppfattningens utveckling. Centrala miljösociologiska och miljöpolitologiska referenser är Pekka Jokinens och Yrjö Hailas verk. I avhandlingen ingår en empirisk fallstudie av de reaktioner som Helsingfors stads försök att implementera EU:s naturskyddsprogram Natura 2000 väckte hos medborgarorganisationer för naturskydd och friluftsliv. Med hjälp av problemformuleringen söks svar på frågor om vilka argument, konflikter och allianser som kännetecknar miljöaktivisters och fritidskonsumenters kommunikation med varandra och planläggande myndigheter. Som empiriskt material används myndigheters plandokument och medborgarorganisationernas utlåtanden angående dem. Som metod för analysen av det empiriska textmaterialet används diskurs- och argumentationsanalys. Den empiriska studien visar att medborgarorganisationerna ingår allianser för att kunna bevaka sina intressen och påverka den lokala miljöförvaltningens beslutsfattande. De här organisationerna är missnöjda med den möjlighet till brukardemokrati som den lokala miljöförvaltningen ger dem. Teoretiska och konkreta exempel på nätverk och konventioner som en lösning på bristen av brukardeltagande framförs i arbetet. Bland teoretiska lösningar kan nämnas Giddens och Castells nätverksteorier. Konkreta exempel lyfts fram ur det empiriska materialet och i form av Kaisa Raitios studie av medling i konflikter mellan renskötare och skogsägare i Lappland.
  • Björklund, Ann-Sofie (2002)
    I teoridelen behandiades ackulturation och flyktingbarns anpassning till det nya samhället. J.W. Berrys ackulturationsteori användes som grund för arbetet. Föräldrarnas situation i det nya landet konstaterades inverka på barnens hälsa. Därför behandlades även det. Det sociala arbetets betydelse för flyktingfamiljer behandlades också. En kvantitativ undersökning utfördes genom korrelations- och regressionsanalyser, med material från en longitudinell undersökning. Sambandet mellan variabler och symtom, samt variablers påverkan på symtommängden undersöktes. Syftet med studien var att undersöka vilka faktorer som innverkar på välmåendet och leder till symtom hos flyktingbarn. Det undersöktes också ifall det förekommer en ökning eller minskning av symtom med tiden. Hypotes l: Ju negativare händelser barnen upplevt, samt ju flera negativa faktorer som finns med i bilden, desto mera symtom har barnen. Hypotes 2: Marginalisering, förluster, traumatiska erfarenheter, samt föräldrarnas frånvaro (separation eller död) antogs vara av stor betydeise för barnens mentala hälsa. Resultaten visade att symtom ökade från tidpunkt ett till tidpunkt två. Psykiska problem hos modern påverkade symtom starkast i samband med den första tidpunkten. Traumatiska erfarenheter och hastighet angående flykten påverkade symtom mest vid den andra tidpunkten. Förluster visade sig inte påverka förekomsten av symtom. Ju flera negativa faktorer som fanns med, desto större visade sig sannolikheten vara för psykiska problem. I samverkan med andra hade föräldrarnas närvaro, psykiska problem hos modern, föräldrarnas brist på kontakt med sina landsmän, samt barnens kön och ålder ett betydande samband med symtomen hos flyktingbarnen. Även bristande socialt nätverk hos barnet visade sig ha betydelse vid den första tidpunkten. Äldre barn hade mera symtom och symtomförekomsten var mycket större bland pojkar än bland flickor. Viktiga källor: Ba Thien, N. & Malapert, B. (1988). The Psychological Consequences for Children of War Trauma and Migration. ln Miserez, (Ed.) Refugees - The Trauma of Exile. Dordrecht: Martinus Nijhoff publishers, 248-286. Berry, J.W. (1992). Acculturation and Adaptation in a New Society. lnternationai Migration: voi. 30, 69-85. Sosiaali- ja terveysministeriön monistetta 1992: 20. Pakolaistyö - sosiaalityön uusi maailma. Helsinki: Sosiaali- ja terveysministeriö: Pakolaistoimisto.
  • Ingman, Ulla-Britt (2007)
    Avsikten med min pro gradu avhandling är att forska i hur flyktingföräldrar upplever sin föräldraroll i diasporan. Det regionala perspektivet är landsbygden i svenska Österbotten. Jag har utgått från föräldrarnas perspektiv och valt kvalitativ forskningsmetodik och temaintervjuer för att kunna intervjua åtta invandrarföräldrar från Bosnien och därmed ta del av deras upplevelser. Vad innebär det att vara förälder med kanske bristfälliga kunskaper i språk och kultur i ett nytt land? Hur har det finländska samhället påverkat föräldrarollen och hur upplevs föräldraskapet i det nya hemlandet? Jag lyfter även fram mottagandet av flyktingar på landsbygden och diskuterar hur integrationen har fungerat i ett agrart samhälle, eftersom tidigare integrationsforskning begränsats till mera urbana miljöer. Jag utgår från att redogöra för vad flyktingskap är ur en teoretisk utgångspunkt i lagstiftning, utanförskap och liminalitet. Själva flykten förklaras utgående från van Genneps övergångsritteori (1999) som exemplifierar hur flyktingarna står på sidan om eller ”mittemellan”. Därefter diskuteras begreppet föräldraskap och jag undersöker om det finns olikheter i synen på uppfostran mellan den bosniska och finländska kulturen. Andra frågor jag tar upp är hur familjen och samhället påverkar föräldrarna och barnen i diasporan och vilken inverkan de transnationella kontakterna har. Slutligen vilken betydelse har den kulturella bakgrunden i kontakten med det nya samhället och dess invånare. Jag har prövat mitt empiriska material utgående från Berrys (1980) ackulturationsteori som omfattar kontakt-, konflikt-, och anpassningsskeden för att analysera vilka områden som upplevts som problematiska och för att analysera vilket stöd de eventuellt har kunnat få samt på vilket sätt föräldrarna eventuellt kunnat ta del av det finländska samhället. Ur det empiriska materialet steg centrala utmaningar i uppfostran upp till ytan. Dessa var oron för barnen, den socioekonomiska situationen, kulturella skillnader och drömmen om hemlandet. Livet i den diasporiska verkligheten har inneburit både oro och förväntningar på framtiden och då speciellt när det gällt barnen. Trots längtan till hemlandet har språkundervisningen och arbetsplatsen utgjort grunden för integrationen i samhället. Att utgå från den egna kulturens föräldraroll samtidigt som de ganska långt omfattat den nya kulturens föräldraroll torde ha gett en stabil grund att stå på. Stödet från skolan, arbetskamraterna och vårdpersonal har även ansetts vara värdefullt för utveckling av föräldrarollen. Centrala begrepp: flyktingskap, föräldraskap, diaspora, landsbygd, ackulturation
  • Helenius, Axel Gabriel (1877)
  • Gröning, Petter (2005)
    I min undersökning har jag granskat det svenskspråkiga nyhetsutbudet som Finska notisbyrån producerar. Målsättningen med min undersökning har varit att undersöka om FNB:s nyhetsprioritering lever upp till de finlandssvenska kundtidningarnas önskemål, dels gällande prioriteringen men också kvaliteten av nyhetstexterna. Jag bygger min undersökning på teorier om nyhetsvärdering och gatekeeping men själva undersökningen har en ganska praktisk utgångspunkt. Jag genomförde undersökningen i två olika delar. Den första delen bestod av att sammanställa frekvenstabeller. Jag förde bok över det nyhetsmaterial FNB skickat ut och kontrollerade vilka texter de finlandssvenska kundtidningarna publicerade. Metoden var alltså renodlat kvantitativ. Undersökningsperioden var sju dagar. Den andra delen utgjordes av en enkät som jag skickade till kundtidningarna och som hade en lite mer kvalitativ utformning. Resultaten visar att de finlandssvenska kundtidningarna är mycket beroende av FNB. Speciellt de större tidningarna Hufvudstadsbladet, Vasabladet och Jakobstads Tidning använder ansenliga mängder FNB-texter varje dag. Vidare kom jag fram till att tidningarna mest av allt använder klassiskt nyhetsmaterial - entydiga och slagkraftiga nyhetsnotiser om exempelvis brott, straff och olyckor. I de politiska texterna och utrikestexterna används texter om elitpersoner och elitnationer i hög utsträckning. Texterna med dålig genomslagskraft saknade ofta en klar och tydlig nyhetskrok, det kunde exempelvis handla om analyser eller förhandstexter. Enkätundersökningen visade att kundtidningarna i stort sett är nöjda med FNB:s nyhetsprioritering och service i största allmänhet. Däremot klagade tidningarna på FNB:s språk, tidningarna ansåg att språket är för byråkratiskt och styvt. I teoridelen hade jag stor nytta av Håkan Hvitfelts undersökningar om nyhetsvärdering och Pamela Shoemakers böcker om gatekeeping. Oliver Boyd-Barrett var min huvudsakliga källa gällande nyhetsbyråverksamhet i största allmänhet och för metoddelen använde jag mig bland annat av Åsa Nilssons redogörelse för kvantitativ innehållsanalys. Min främsta materialkälla var frekvenstabellerna som jag sammanställde hösten 2004 och enkätundersökningen som jag genomförde vintern 2005.
  • Nevanen, Saila (Helsingin yliopisto, 2015)
    This research focuses on one arts education project which was carried out in Helsinki in early childhood education centres and schools. This study is an evaluation research which concentrates on art education s connections to learning, wellbeing and communality; it views kindergarten and school as arts learning environments and at arts education as a multiprofessional col-laboration between teachers and artists. The arts education project, which was started in Helsinki in 2000, was offered to children who were under school age (3 6 years old) and at ele-mentary school age (7 9 years old). The data consists of interviews of the teachers, artists and principals of the kindergartens (N=23), the narratives of the closing report (N=9) and the follow-up materials of the project. The method of the research was multidimensional evaluation. The research includes five independent articles and a summary that con-nects the entirety of the research. Each theme is included in one independ-ent article, each of which was published in international peer-reviewed journals. Article I analyses the multiprofessional collaboration between teachers and artists. Article II focuses on the possibilities of arts education in developing learning abilities. Article III explores kindergarten and school as learning environments of arts education. Article IV highlights the evalua-tion of the arts education project through a multidimensional evaluation method. The last article, number V, analyses the long-term impacts of the arts education project in kindergartens and schools. The results show that well-executed, long-lasting arts education projects may support and promote children s wellbeing and their learning abilities. It was easy to motivate and direct the children in activities that connected target-oriented work with natural play. Arts education can also be used to strengthen the unity of the community between early childhood education centres, schools and neighbourhoods. The multiprofessional collaboration between the teachers and artists con-nected their skills and professional abilities, but successful cooperation also required the ability to handle additional interests and tensions. The long-term impact evaluation showed that five out of ten participating kindergartens still continue the developmental work started in the project. The project work was also seen as an excellent way to continue or update training.
  • Vakkari, Johanna (Suomen Muinaismuistoyhdistys, 2007)
    My doctoral dissertation is on Johan Jakob Tikkanen (1857 1930), the first professor of art history in Finland, and his significance and methods in the context of late 19th and early 20th-century European art history. Tikkanen was one of the pioneering scholars in the field of medieval art research, and, along with Anton Springer, Heinrich Wölfflin, Aloïs Riegl, Adolfo Venturi, Franz Wickhoff, Julius von Schlosser, Aby Warburg, Emile Mâle and others, one of the scholars who defined art history as an independent academic discipline. Tikkanen s scholarly interests and his methods resemble those of many formalistically oriented German and Austrian art historians of his time. He became well known throughout Europe, mainly for his studies on illustrated medieval manuscripts. Tikkanen s dissertation, Der Malerische Styl Giotto s Versuch zu einer Characteristik Desselben, from 1884 was regarded in its day as the best form-analytical study on the painter. It has a central position in the present thesis, as it already included nearly all the methods that Tikkanen used and elaborated upon throughout his career. Giotto also gives a good perspective for comparing Tikkanen s ideas with a long art-historical tradition. Tikkanen was profoundly interested in artistic creativity. In his own words, he wanted to study das künstlerische Können , artistic ability, instead of das künstlerische Wollen or artistic will, which was an important theoretical issue in art history in the late 19th century. This starting point led him to the history of style and iconographical research. Along with the Danish art historian, Julius Lange, he was one of the first scholars who began to study the meaning of gestures and postures in art. In my dissertation I have emphasized the importance of Tikkanen s personal art education. I regard it as having influenced both his scholarly argumentation and his working methods. I have also written a short overview of the situation of art history in Finland and in Northern Countries before Tikkanen s time in order to give an idea of his scientific background. My thesis is a critical and historiographical study on J. J. Tikkanen s role in the development of art history and its methodology.
  • Lehtonen, Sini (2015)
    Tämän tutkielman tarkoituksena on esitellä focus stacking -algoritmien toimintaa. Focus stacking on digitaalinen kuvankäsittelymenetelmä, jossa yhdistetään useita eri kuvia, joissa jokaisessa eri osa kohteesta on tarkka. Kuvista erotetaan tarkat kohdat ja kootaan ne uudeksi kuvaksi. Näin saadaan muodostettua kuva, jossa koko kuvauksen kohde on mahdollisimman tarkka. Tässä tutkielmassa perehdytään kahteen eri tapaan tunnistaa kuvien tarkat kohdat, gradientin ja Fourier-muunnoksen avulla tapahtuvaan tunnistamiseen. Tutkielman alussa, luvussa kaksi, esitellään focus stacking -algoritmien toteuttamiseen tarvittavaa teoriaa. Luvun alussa selostetaan digitaaliseen kuvaan ja valokuvaukseen liittyvää termistöä. Tämän jälkeen esitellään gradientin teoriaa ja kerrotaan, miten gradientti voidaan laskea kuvalle erilaisten konvoluutioytimien avulla. Seuraavaksi selostetaan teoriaa Fourier-muunnoksesta, erityisesti diskreetissä tapauksessa. Lisäksi tarkastellaan nopeaa Fourier-muunnosta. Luvun lopuksi tarkastellaan vielä ali- ja ylipäästösuodatusta. Kolmannessa luvussa esitellään työssä käytettävä aineisto eli itse otetut kuvat, joiden kohteena on kolme laskettelevaa pupua. Jokaisessa kuvassa eri pupu on tarkka. Tavoitteena on saada muodostettua algoritmeja käyttäen kuva, jossa kaikki kolme pupua olisivat mahdollisimman tarkkoja. Luvussa neljä esitellään menetelmät, joista gradienttimenetelmässä vertaillaan tarkkoja ja epätarkkoja alueita gradienttien magnitudeista laskettujen normien avulla ja Fourier-muunnosmenetelmässä Fourier-muunnosten normien avulla. Luvussa viisi esitellään molemmilla menetelmillä eri parametrien arvoilla saatuja tuloksia. Käytettävissä algoritmeissa on kolme muutettavaa parametria, kerrallaan tarkasteltavan alueen koko, kynnys ja Fourier-muunnosmenetelmässä vielä ylipäästösuodatuksen rajataajuus. Kuvia vertaillaan siis aina tarkasteltavan alueen kokoinen pala kerrallaan. Kynnys tarkoittaa lukua, jonka alle jääviä normeja vastaavat alueet valitaan esimerkiksi ensimmäisestä kuvasta. Nämä alueet ovat siis kaikissa kuvissa epätarkkoja. Kynnyksen avulla varmistetaan, että epätarkasta alueesta saadaan tasainen. Johtopäätöksissä, luvussa kuusi, tarkastellaan saatuja tuloksia, jotka ovat yllättävän hyviä. Parhaan gradienttimenetelmällä ja parhaan Fourier-muunnosmenetelmällä saadun kuvan välillä ei ole suurta eroa. Kummassakin kuvassa on joitakin virheitä eli epätarkkoja pikseleitä. Gradienttimenetelmässä tarkkojen alueiden reunat tulevat helpommin tasaisemman näköisiksi kuin Fourier-muunnosmenetelmässä, mutta kuviin jää usein kokonaisia epätarkkoja alueita. Fourier-muunnosmenetelmässä reunoihin jää usein pieniä epäsäännöllisen muotoisia epätarkkoja alueita. Parametrien arvoista erityisesti tarkasteltavan alueen koolla ja ylipäästösuodatuksen rajataajuudella on suuri merkitys tuloksiin.
  • Birge, Traci (Helsingfors universitet, 2004)
    Productivity and quality of two grazed coastal seashore meadows in Eastern Uusimaa were examined between May and July, 2002. A total of 18 1m2 sample sites divided into four separate cutting regimes were cut by hand to simulate grazing in the meadow. cutting regimes of various intensities were used to simulate the short term effects of different grazing pressures on the quality and productivity of the vascular plant forage in the meadows. Samples were dried, weighed and analysed for digestibility and composition. Digestibility analysis was carried out using in vitro digestibility analysis. A CNS- 1000 Elemental Analyzer was used to measure carbon, nitrogen and sulphur content of selected samples. The results showed that cumulative above ground phytomass productivity (AGPP) was dependent upon both biotope and cutting regime in the large (40 ha) Bosgård meadow, and that interaction betweeen these two factors was significant. The results of the smaller (<2 ha) Majvik meadow were highly variable between replicates. This variation overshadowed possible effects of biotope and cutting regime and their interaction. Quality was dependent upon both biotope and cutting regime. D-value decreased over time.
  • Westerholm, Fia (1995)
    21 hundar som lider av EPI deltog i ett utfodringsexperiment för att man skulleutreda näringssammansättningens inverkan på fettabsorption och avföringens hydrolasaktivitet. Fem hundar deltog dessutom i endoskopisk undersökning och av dem togs biopsier från tunntarmen. Hundarna deltog i fyra utfodringsperioder, av vilka den första var en tvåveckor lång ordinärdietperiod och de tre följande specialdietperioder. Specialdieterna utgjordes av ett med moderat fett- och fiberhalt (i/d), ett med hög fiberhalt(R/d) och ett med hög fetthalt(p/d). I slutet av varje period togs all under ett dygn producerad avföring tillvara och analyserades efter avslutade dietperioder med avseende på amylas-lipasproteas-aktiviteterna i avföringe n. Fettåbsorptionen uträknades i relation till hundens kroppsvikt. För alla specialdietperioder var den genomsnittliga absorptionen lägre än hos friska hundar. Hos friska hundar är fettabsorptionen över 90%, medan våra försökshundar under samtliga dieter hade en absorption under 90% (r/d 83%, i/d85%, p/d 83%). Fettmängden i avföringen i relation till hundens vikt låg församtliga foder över referensvärdet för friska hunda (0.3 g/kg kroppsvikt), samtliga över 0.6 g/kg kroppsvikt. Samtliga enzymaktiviteter nådde sina minsta värden då hundarna utfodrades med r/d (p mindre än 0.05) i relation till övriga dieter. I den histologiska delen deltog fem hundar, hos vilka kunde påvisas en statistiskt signifikant sänknig i antalet lymfocyter i lamina propria med r/d, i jämförelse med p/d. Antalet plasmaceller, som skulle indikera en inflammation,sjöek också då hundarna utfodrades med r/d och var statistiskt signifikant i förhållande till i/d. R/d innehåller cellulosa, som har ansetts binda lipas, liksom övriga fibrer. Denna undersökning skulle tyda på att så inte är fallet. Utfodring med ett foderinnehållande en stor fibermängd minskar eventuellt en inflammatorisk process i tunntarmens slemhinna.
  • Peltonen, Jenni (Helsingin yliopisto, 2015)
    The first part of this thesis consists of literature review focusing on the folate vitamer chemical characteristics, the role of folate in human nutrition and health, the characteristics of folate in vegetables, berries and mushrooms, and also the determination of food folate. The second part reviews the experimental section of the study. Many food composition databases are lacking the folate content of unusual vegetables, berries and mushrooms. The objective of the experimental study was determination of total folate content in certain vegetables, berries and mushrooms using microbiological assay (MA) to update Fineli ® - Finnish Food Composition Database and also to study their folate vitamer distribution using ultra-high performance liquid chromatography (UHPLC). Vegetables contained more folate than berries and mushrooms. In vegetables total folate content ranged from 25 to 108 µg/100 g (fw), in berries from 11 to 38 µg/100 g (fw) and in mushrooms from 4 to 30 (fw) µg/100 g. In vegetables the highest folate content was in rocket (108 µg/100 g fw), and in berries in raspberry and in cloudberry (38 µg/100 fw). In mushrooms overwhelmingly more folate was penny bun (30 µg/100 g fw). Based on the four primary samples of chanterelles, growing region affects mushroom folate content and vitamer distribution. Chanterelles from Estonia had more than triple amount of folate compared to chanterelles from Finland (Estonia 13,3 µg/100 g fw; Mäntyharju (Finland) 4,3 µg/100 g fw). Expectedly the predominant folate vitamer in vegetables and berries was 5-CH3-H4-folate. In berries 5-CH3-H4-folate constituted 87–100 % of the vitamer sum, except for blueberry which had lower proportion of 5-CH3-H4-folate (33 %). Coriander, rocket, roman salad and lamb’s lettuce contained also a high amount of 10-CHO-folic acid (28–54 %). Affinity chromatographic purification was not suitable purification method for most mushrooms species. In particular penny bun and northern milk-cap formed a viscous solution which made the filtering and cleaning difficult. On the other hand, the purification method seemed to be more suitable for chanterelles and based on that mushrooms’ folate vitamer distribution was more versatile than that of vegetables and berries.
  • Zhang, Yuetuan (Helsingin yliopisto, 2015)
    The literature review described the importance of folate enhancement to human health especially to coeliac patients with an introduction to folate analysis, pseudocereals and possible fortification methods. The aim of this study was to study the natural folate enhancement methods in pseudocereal matrix. Pseudocereal materials consisted of buckwheat, amaranth and quinoa, each of which was subjected to three different treatments: germination, fermentation and combined treatment. Total folate determination was based on an official microbiological assay method (Lactobacillus rhamnosus ATCC 7469). Germination of pseudocereals lasted for 4–5 days. Fermentation was conducted using either baking yeast Saccharomyces cerevisiae ALKO743 or LAB Streptococcus thermophilus ABM5097. All germinated whole grain pseudocereals indeed showed a significant increase in total folate content. Specifically, the increase was 5.4-fold in buckwheat, 5-fold in amaranth and 2.6-fold in quinoa. Fermentation of native pseudocereals also enhanced total folate level. As for the combined treatment, the total folate level of germinated seeds did not further significantly increase or decrease in later fermentation period. Although more studies are needed for processing real pseudocereal foods, our study showed great potential of folate enhancement using germination or fermentation.
  • Kariluoto, Susanna (Helsingin yliopisto, 2008)
    The average daily intake of folate, one of the B vitamins, falls below recommendations among the Finnish population. Bread and cereals are the main sources of folate, rye being the most significant single source. Processing is a prerequisite for the consumption of whole grain rye; however, little is known about the effect of processing on folates. Moreover, data on the bioavailability of endogenous cereal folates are scarce. The aim of this study was to examine the variation in as well as the effect of fermentation, germination, and thermal processes on folate contents in rye. Bioavailability of endogenous rye folates was investigated in a four-week human intervention study. One of the objectives throughout the work was to optimise and evaluate analytical methods for determining folate contents in cereals. Affinity chromatographic purification followed by high-performance liquid chromatography (HPLC) was a suitable method for analysing cereal products for folate vitamers, and microbiological assay with Lactobacillus rhamnosus reliably quantified the total folate. However, HPLC gave approximately 30% lower results than the microbiological assay. The folate content of rye was high and could be further increased by targeted processing. The vitamer distribution of whole grain rye was characterised by a large proportion of formylated vitamers followed by 5-methyltetrahydrofolate. In sourdough fermentation of rye, the studied yeasts synthesized and lactic acid bacteria mainly depleted folate. Two endogenous bacteria isolated from rye flour were found to produce folate during fermentation. Inclusion of baker s yeast in sourdough fermentation raised the folate level so that the bread could contain more folate than the flour it was made of. Germination markedly increased the folate content of rye, with particularly high folate concentrations in hypocotylar roots. Thermal treatments caused significant folate losses but the preceding germination compensated well for the losses. In the bioavailability study, moderate amounts of endogenous folates in the form of different rye products and orange juice incorporated in the diet improved the folate status among healthy adults. Endogenous folates from rye and orange juice showed similar bioavailability to folic acid from fortified white bread. In brief, it was shown that the folate content of rye can be enhanced manifold by optimising and combining food processing techniques. This offers some practical means to increase the daily intake of folate in a bioavailable form.
  • Shmelev, Anton (Helsingin yliopisto, 2007)
    The present study analyses the traffic of Hsp150 fusion proteins through the endoplasmic reticulum (ER) of yeast cells, from their post-translational translocation and folding to their exit from the ER via a selective COPI-independent pathway. The reporter proteins used in the present work are: Hsp150p, an O-glycosylated natural secretory protein of Saccharomyces cerevisiae, as well as fusion proteins consisting of a fragment of Hsp150 that facilitates in the yeast ER proper folding of heterologous proteins fused to it. It is thought that newly synthesized polypeptides are kept in an unfolded form by cytosolic chaperones to facilitate the post-translational translocation across the ER membrane. However, beta-lactamase, fused to the Hsp150 fragment, folds in the cytosol into bioactive conformation. Irreversible binding of benzylpenicillin locked beta-lactamase into a globular conformation, and prevented the translocation of the fusion protein. This indicates that under normal conditions the beta-lactamase portion unfolds for translocation. Cytosolic machinery must be responsible for the unfolding. The unfolding is a prerequisite for translocation through the Sec61 channel into the lumen of the ER, where the polypeptide is again folded into a bioactive and secretion-competent conformation. Lhs1p is a member of the Hsp70 family, which functions in the conformational repair of misfolded proteins in the yeast ER. It contains Hsp70 motifs, thus it has been thought to be an ATPase, like other Hsp70 members. In order to understand its activity, authentic Lhs1p and its recombinant forms expressed in E. coli, were purified. However, no ATPase activity of Lhs1p could be detected. Nor could physical interaction between Lhs1p and activators of the ER Hsp70 chaperone Kar2p, such as the J-domain proteins Sec63p, Scj1p, and Jem1p and the nucleotide exchange factor Sil1p, be demonstrated. The domain structure of Lhs1p was modelled, and found to consist of an ATPase-like domain, a domain resembling the peptide-binding domain (PBD) of Hsp70 proteins, and a C-terminal extension. Crosslinking experiments showed that Lhs1p and Kar2p interact. The interacting domains were the C-terminal extension of Lhs1p and the ATPase domain of Kar2p, and this interaction was independent of ATPase activity of Kar2p. A model is presented where the C-terminal part of Lhs1p forms a Bag-like 3 helices bundle that might serve in the nucleotide exchange function for Kar2p in translocation and folding of secretory proteins in the ER. Exit of secretory proteins in COPII-coated vesicles is believed to be dependent of retrograde transport from the Golgi to the ER in COPI-coated vesicles. It is thought that receptors escaping to the Golgi must be recycled back to the ER exit sites to recruit cargo proteins. We found that Hsp150 leaves the ER even in the absence of functional COPI-traffic from the Golgi to the ER. Thus, an alternative, COPI-independent ER exit pathway must exists, and Hsp150 is recruited to this route. The region containing the signature guiding Hsp150 to this alternative pathway was mapped.
  • Heikkilä, Annukka (Helsingin yliopisto, 2013)
    Follicular thyroid carcinoma (FTC) is the second most common malignancy of the thyroid gland, with predisposing genetic alterations such as rat sarcoma (RAS) mutation and paired box gene 8-peroxisome proliferator-activated receptor γ (PAX-PPARγ) alteration, as well as suggested risk factors such as iodine insufficiency and female gender. Distinguishing FTC from the most common neoplasm of the thyroid, follicular thyroid adenoma (FTA), or even from a non-neoplastic goitrous nodule, is often impossible preoperatively, leading to unnecessary surgery and exposing patients to surgical complications. In this study, 127 follicular thyroid neoplasia patients (83 FTAs and 44 FTCs) treated at Helsinki University Central Hospital (HUCH) in Finland between 1990 and 2009 were examined to find methods for differential diagnosis between follicular thyroid lesions. Tissue markers were investigated by immunohistochemistry in follicular neoplasms and non-neoplastic control tissues, and were correlated with clinical parameters, such as with metastatic disease and survival. Additionally, cancer registry data were gathered, concerning the diminishing incidence of FTC accompanied by an increase in the incidence of papillary thyroid carcinoma. Carcinomas were reanalysed according to the new World Health Organization classification of endocrine tumours, in which a new tumour entity, poorly differentiated carcinoma of the thyroid, was introduced. Markers with possible clinical utility were found; e.g. in an attempt to differentiate between non-neoplastic and neoplastic follicular lesions of the thyroid (HES5) as well as between FTA and FTC (MIB-1, Cyclin D1, TLR-2, ERβ), a marker with prognostic value in carcinomas (ERβ), as well as a marker correlating with the presence of metastatic disease (TLR-4). These results aid in the challenging field of diagnostics in follicular thyroid lesions. Measuring the expression of HES5 may help in differentiating between neoplastic and non-neoplastic follicular thyroid lesions. Markers, such as MIB-1 and ERβ, are partly able to differentiate between benign and malignant follicular thyroid neoplasias, whereas ERβ and TLR-4 have prognostic value in FTC.