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(2021)Kirjallisuuskatsauksessa käydään läpi erilaisia menetelmiä C3-substituoitujen indolien synteeseihin 2-alkenyylianiliinityyppisistä lähtöaineista, joiden bentsyylinen asema oli substituoitu. Erityistä huomiota kiinnitetään menetelmiin, joiden reaktiomekanismeiksi ehdotettiin radikaalimekanismeja. Myös näitä ehdotettuja radikaalimekanismeja esitellään tutkielmassa. Kokeellisessa työssä tutkittiin C3-subsituoitujen indolien hapettavaa synteesiä hiilikatalyytin avulla. Lähtöaineina käytettiin bentsyylisesti aryylisubstituoituja 2-alkenyylianiliinijohdannaisia. Joidenkin lähtöaineiden typpeen oli kiinnitetty metoksipyridiini, jonka kiinnitystä varten kehitettiin Buchwald-katalyysi. Hiilikatalyysit tuottivat hyviä saantoja. Korkea elektronitiheys, etenkin aniliinin bentseenirenkaan ja/tai typen aromaattisen substituentin korkea elektronitiheys, oli eduksi. Reaktion mekanismin ehdotetaan alkavan hapettumisella radikaalikationiksi, ja näitä hapetuspotentiaaleja laskettiin aiemmin raportoidun menetelmän mukaisesti. Mikäli indolin 5-renkaan substituutiot (N1, C2, C3) olivat tarpeeksi samankaltaisia, korkea elektronitiheys, matala hapetuspotentiaali ja hyvä saanto korreloivat. Indolin 5-renkaan substituutio on kuitenkin merkittävämpi tekijä kuin hapetuspotentiaali ja/tai korkea elektronitiheys. Pyridiini typen suojaryhmänä toimi katalyysissä ja se onnistuttiin poistamaan helposti. Metoksipyridiini toimi katalyysissä hyvin, mutta sen kvantitatiivinen poistaminen ei onnistunut.
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(2013)Tutkielma on rakenteeltaan kaksiosainen. Kirjallisuustutkimus on tehty Helsingin yliopistossa ja kokeellinen tutkimus Espanjassa (Universidad Complutense de Madrid). Tästä johtuen ensimmäinen osa on kirjoitettu suomeksi ja toinen osa englanniksi. Kirjallisuuskatsauksessa perehdytään C6-substituoitujen pyrimidiininukleosidien valmistukseen. C6-substituoiduilla pyrimidiininukleosideilla on havaittu olevan monia erilaisia biologisia vaikutuksia. C6-substituoiduista pyrmidiininukleosideista ei ole kovin paljon julkaisuja johtuen synteettisten keinojen vähäisyydestä. C6-substituoituja pyrimidiininukleosideja voidaan valmistaa joko yhdistämällä C6-substituoitu silyloitu emäs ja suojattu sokeri tai muokkaamalla suoraan valmiin nukleosidin C6-asemaa. Happamissa olosuhteissa glykosylaatioreaktiolla valmistettujen C6-substituoitujen pyrimidiininukleosidien saantoa voidaan parantaa käyttämällä Friedel-Crafts-katalyyttejä ja suojaamalla emäksen N3-asema. Glykosylaatioreaktiolla valmistettujen pyrimidiininukleosidien C6-asemassa olevat substituentit ovat yleensä pieniä ryhmiä. Valmiin pyrimidiininukleosidin C6-aseman muokkaukseen on useita keinoja, joista palladiumkatalyytit tarjoavat yhden tehokkaimmista keinoista liittää esimerkiksi aryyliryhmiä C6-asemaan. Muokkaamalla valmista nukleosidia vältetään myös glykosylaatioreaktiossa syntyvien N3-isomeerien muodostuminen. Joidenkin substituenttien kohdalla havaittiin N-glykosidisidoksen hajoamista. Kokeellisen tutkimuksen tavoitteena oli valmistaa uusia asymmetrisessä katalyysissä käytettäviä kiraalisia kamferijohdannaisia ligandeja. Kahden kamferijohdannaisen ligandin valmistuksessa saatiin valmistettua lupaavia välituotteita. Kolme polyhydroksyloitunutta norbornaani- johdannaista eivät toimineet kiraalisina ligandeina vaan tuottivat raseemisen seoksen.
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(Helsingin yliopistoUniversity of HelsinkiHelsingfors universitet, 2004)
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(2012)In analysis of structural information for transmembrane (TM) proteins it is ideal to work with a three-dimensional (3D) structure. This is not always possible as determining an accurate 3D structure can be challenging and expensive as pursuing one can take large amounts of time. Sequence analysis is often used as a surrogate to determine a subset of information regarding secondary and tertiary protein structure given the primary structure (an amino acid sequence). Using Equilibrative Nucleoside Transporter member 1 (ENT1) as a model, the objective of predicting secondary and tertiary structure given primary structure is attempted through computational (in silico) methods. The in silico methods include the use of a pipeline of programs spanning both custom made and ready built software. A set of 2034 homologous protein sequences are first obtained from the initial human ENT1 (hENT1) sequence through a BLASTp. This sequence information is then processed to acquire information on variation, conservation, and hydrophobicity through topology prediction, hydropathic moment plots and variation moment plots. Comparing these results with data acquired from Glycerol-3-Phosphate Transporter (GlpT), a protein with a known 3D structure of 3.3 Angstrom resolution is done to assess evidence of evolutionary origin. This in turn allows estimation on the reliability of predictions to be made on aspects of the secondary and tertiary structure for hENT1. The results show that within predicted TM alpha helical regions that there is some level of correlation between the variation of the amino acids within the alpha helical TM region and its orientation towards the membrane. This can be further refined by gathering statistics on other known proteins with a 3D structure for their relationships in TM regions to hydrophobicity and variability. This will aid in secondary and tertiary structure predictions of other TM proteins given further refinement and additional data. In addition, the sequence conservation information obtained should prove to be robust and allow for a large number of sequences to be analyzed to determine conservation of amino acids given a reference protein. Ideally this information will provide aid in determining interesting amino acids for experiments to be done on hENT1.
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(2023)The outsourced emissions, particularly from transport and construction, pose a challenge for cities like Helsinki in achieving carbon neutrality. Helsinki, epitomizing this struggle, unveiled the 'Carbon-neutral Helsinki 2035 Action Plan' in 2018, aiming to achieve carbon neutrality by 2030. However, this plan, primarily employing a production-based emissions accounting method, neglects the crucial aspect of outsourced emissions. This thesis undertakes a focused examination of the outsourced emissions in Helsinki's transport sector, utilizing a consumption-based emissions accounting method, with a particular focus on emissions originating from car traffic. To ensure a comprehensive evaluation of emissions, this study employs a fleet-based life-cycle assessment (LCA) methodology, providing a holistic perspective encompassing the entire life cycle of vehicles. This approach diverges from conventional product-centric LCAs, incorporating the dynamic interplay between production, usage, and disposal. The study's outcomes are contrasting against the City of Helsinki's Business-As-Usual scenario, emphasizing electrification and technological advancements to reduce emission intensity. Key research questions include uncovering disparities between consumption-based and production-based methodologies, assessing the feasibility of Helsinki's emission reduction goals, and exploring differences between fleet-based and traditional LCA approaches. The thesis is organized into eight chapters, delineating the analytical framework, City of Helsinki's emission mitigation efforts, methodology, data, results, and concluding insights. The consumption-based methodology illuminates substantial disparities in emissions compared to the production-based approach, posing formidable challenges for Helsinki's emission reduction aspirations. The study emphasizes the imperative of actively curtailing the number of vehicles and promoting alternative modes of transportation to achieve meaningful reductions. The fleet-based LCA methodology not only provides a nuanced understanding of emissions but also highlights the necessity of considering evolving technologies and lifecycles. To make significant strides in emissions reduction, Helsinki must adopt a comprehensive and transparent approach, surpassing mere reporting standards and actively contributing to global climate efforts. The study underscores the urgency for cities to transcend greenwashing tactics, aligning policies with public sentiment, and committing to tangible actions for a sustainable future.
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(2023)Polygenic risk scores (PRSs) estimate the genetic risk of an individual for a certain polygenic disease trait by summing up the effects of multiple variants across the genome affecting the disease risk. Currently, polygenic risk scores (PRSs) are calculated from imputed array genotyping data which is inexpensive to produce use and has standard procedures and pipelines available. However, genotyping arrays are prone to ascertainment bias, which can also lead to biased PRS results in some populations. If PRSs are utilized in healthcare for screening rare diseases, usage of whole-genome sequencing (WGS) instead of array genotyping is desirable, because also individual samples can be analyzed easily. While high-coverage WGS is still significantly more expensive than array genotyping, low-coverage whole genome sequencing (lcWGS) with imputation has been proposed as an alternative for genotyping arrays. In this project, the utility of imputed low-coverage whole-genome sequencing (lcWGS) data in PRS estimation compared to genotyping array data and the impact of the choice of imputation tool for lcWGS data was studied. Down-sampled WGS data with six different low coverages (0.1x-2x) was used to represent lcWGS data. Two different pipelines were used in genotype imputation and haplotype phasing: in the first one, pre-phasing and imputation were performed directly for the genotype likelihoods (GLs) calculated from the down-sampled data, whereas in the second one, the GLs were converted to genotype calls before imputation and phasing. In both pipelines, PRS for 27 disease phenotypes were calculated from the imputed and phased lcWGS data. Imputation and PRS calculation accuracy of the two pipelines were calculated in relation to both genotyping array and high-coverage whole-genome sequencing (hcWGS) data. In both pipelines, imputation and PRS calculation accuracy increased when the down-sampled coverage increased. The second imputation and phasing pipeline lead to better results in both imputation and PRS calculation accuracy. Some differences in PRS accuracy between different phenotypes were also detected. The results show similar patterns to what is seen in other similar publications. However, not quite as high imputation and PRS accuracy as seen in earlier studies could be attained, but possible limitations leading to lower accuracy could be identified. The results also emphasize the importance of choosing suitable imputation and phasing methods for lcWGS data and suggest that methods and pipelines designed particularly for lcWGS should be developed and published.
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(2018)Parisian cycling increased importantly in the past twenty years. Reviewing fifty years of Parisian transport planning and details of the bike-sharing programme Vélib’, I argue in the background research that municipal biking planning and the public bicycles Vélib’ can explain this development of urban biking (1997-2015). The city also has high ambitions for the biking modal share, aiming for fifteen per cent of all Parisian transport by 2020. I want to discover what the determinants of Parisian biking are, and if the latter can be modelled and predicted; thereby, I can verify if predictions match municipal objectives for 2020. I calculate correlations between the Parisian cycling index and its possible determinants with annual values on biking and other variables from 1997 to 2015 in the first part of the analysis (chapter V). This analysis shows that cycling infrastructure, Vélib’ memberships and gasoline price are the strongest positive biking determinants, while car traffic is the strongest negative determinant. In the second part of the analysis, knowing these determinants, I can find multiple linear regression models with high R-squared values (around 0,97 and 0,98) and low standard errors. The best regression model combines linear infrastructure, car traffic volume and Vélib’ memberships. The predictions in the last part of the analysis chapter reveal that in the current tendencies, the Parisian biking modal share will reach about 7 per cent by 2020, instead of the 15 per cent aimed. But I illustrate how the objective can be accomplished, by either improving drastically one of the determinants or the three of them simultaneously to reach a modal share of 15 per cent. The results and the models found appear to be more satisfactory and accurate than the ones of previous researches, presented in the literature review. The findings may be useful for public authorities and decision-makers during processes of biking planning, and it might contribute to future research in this topic.
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(2012)Tässä tutkielmassa esitellään algebrallisen ryhmän käsite sekä hieman tavallisesta poikkeava tapa ymmärtää permutaatioita. Työn tärkeimpinä kohtina voi pitää Caleyn lausetta, joka yhdistää permutaation ja ryhmän käsitteet, sekä p-ryhmän käsitettä. Työssä käsitellään myös pintapuolisesti suoraan tuloon liittyviä ryhmiä. Varsinaisia esitietovaatimuksia työn ymmärtämiseksi ei ole, mutta tietynlainen matemaattinen yleissivistys on toivottavaa. Kenen tahansa kandidaattitasoisen matematiikan opiskelijan kuitenkin pitäisi pystyä ymmärtämään tämän tutkielman oleellinen sisältö. Esitelmäni perustuu Joseph J. Rotmanin kirjaan An Introduction to the Theory of Groups [2]. Tukena olen käyttänyt Tauno Metsänkylän ja Marjatta Näätäsen teosta Algebra I [1]. Permutaatioita käsittelevässä luvussa olen tukeutunut Pekka Tuomisen Todennäköisyyslaskenta I- kirjaan [3]. Permutaatioita oli tutkittu jo aikaisemminkin, mutta ryhmien teorian tutkimuksen aloitti varsinaisesti Galois (1811-1832). 1800-luvun lopussa ryhmäteoriaa tutkittiin lähinnä kahdessa päähaarassa. Nämä päähaarat olivat algebralliset ryhmät, erityisesti Lien ryhmät, sekä äärelliset ryhmät. 1900-luvulla ilmaantui kuitenkin kolmas päähaara, äärettömät ryhmät. Nykyään ryhmät esiintyvät monilla matematiikan aloilla, esimerkiksi geometriassa, topologiassa ja logiikassa.
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(2020)The feasibility of quantitatively measuring ultrasound in air with a Schlieren arrangement has been demonstrated before, but previous work demonstrating calibration of the system combined with computation to yield the 3D pressure field does not exist. The present work demonstrates the feasibility of this both in theory and practice, and characterizes the setup used to gain the results. Elementary ray optical and Schlieren theory is exhibited to support the claims. Derivation of ray optical equations related to quantitative Schlieren measurements are shown step by step to help understand the basics. A numerical example based on the theoretical results is then displayed: Synthetic Schlieren images are computed for a theoretical ultrasonic field using direct numerical integration, then the ultrasonic field is recovered from the Synthetic Schlieren images using the inverse Abel transform. Accuracy of the inverse transform is evaluated in presence of synthetic noise. The Schlieren arrangement, including the optics, optomechanics, and electronics, to produce the results is explained along with the stroboscopic use of the light source to freeze ultrasound in the photographs. Postprocessing methods such as background subtraction and median and Gaussian filtering are used. The repeatability and uncertainty of the calibration is examined by performing repeated calibration while translating or rotating the calibration targets. The ultrasound fields emitted by three transducers (100 kHz, 175 kHz, and 300 kHz) when driven by 5 cycle sine bursts at 400 Vpp are measured at two different points in time. The measured 3D pressure fields measured for each transducer are shown along with a line profile near the acoustic axis. Pressure amplitudes range near 1 kPa, which is near the acoustic pressure, are seen. Nonlinearity is seen in the waveforms as expected for such high pressures. Noise estimates from the numerical example suggest that the pressure amplitudes have an uncertainty of 10% due to noise in the photographs. Calibration experiments suggest that additional uncertainty of about 2% per degree of freedom (Z, X, rotation) is to be expected unless especial care is taken. The worst-case uncertainty is estimated to be 18%. Limitations and advantages of the method are discussed. As Schlieren is a non-contacting method it is advantageous over microphone measurements, which may affect the field they are measuring. As every photograph measures the whole field, no scanning of the measurement device is required, such as with a microphone or with an LDV. Suggestions to improve the measurement setup are provided.
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(2012)The most important parameters describing the aerosol particle population are the size, concentration and composition of the aerosol particles. The size and water content of the aerosol particles are dependent of the relative humidity of the ambient air. Hygroscopicity is a measure to describe the water absorption ability of an aerosol particle. Volatility of an aerosol defines how the aerosol particles behave as a function of temperature. A Volatility-Hygroscopicity Tandem Differential Mobility Analyzer (VH-TDMA) is an instrument for size-selected investigation of particle number concentration, volatility, hygroscopicity and the hygroscopicity of the particle core, i.e. what is left of the particle after the volatilization. While knowing these qualities of aerosol particles, one can predict their behavior in different atmospheric conditions. Volatility and hygroscopicity can also be used for indirect analysis of chemical composition. The aim of this study was to build and characterize a VH-TDMA, and report the results of its field deployment at the California Nexus (CalNex) 2010 measurement campaign. The calibration measurements validated that with the VH-TDMA one can obtain accurate volatility and hygroscopicity measurements for particles between 20 nm and 145 nm. The CalNex 2010 results showed that the instrument is capable in field measurements at varying measurement conditions; and valuable data about hygroscopicty, volatility and the mixing state of several types of aerosols were measured. The data obtained was in line with the observations based on the data measured with other instruments.
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(2022)In this thesis we investigate the feasibility of machine learning methods for estimating the type and the weight of individual food items from images taken of customers’ plates at a buffet- style restaurant. The images were collected in collaboration with the University of Turku and Flavoria, a public lunch-line restaurant, where a camera was mounted above the cashier to automatically take a photo of the foods chosen by the customer when they went to pay. For each image, an existing system of scales at the restaurant provided the weights for each individual food item. We describe suitable model architectures and training setups for the weight estimation and food identification tasks and explain the models’ theoretical background. Furthermore we propose and compare two methods for utilizing a restaurant’s daily menu information for improving model performance in both tasks. We show that the models perform well in comparison to baseline methods and reach accuracy on par with other similar work. Additionally, as the images were captured automatically, in some of the images the food was occluded or blurry, or the image contained sensitive customer information. To address this we present computer vision techniques for preprocessing and filtering the images. We publish the dataset containing the preprocessed images along with the corresponding individual food weights for use in future research. The main results of the project have been published as a peer-reviewed article in the International Conference in Pattern Recognition Systems 2022. The article received the best paper award of the conference.
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(2022)Can a day be classified to the correct season on the basis of its hourly weather observations using a neural network model, and how accurately can this be done? This is the question this thesis aims to answer. The weather observation data was retrieved from Finnish Meteorological Institute’s website, and it includes the hourly weather observations from Kumpula observation station from years 2010-2020. The weather observations used for the classification were cloud amount, air pressure, precipitation amount, relative humidity, snow depth, air temperature, dew-point temperature, horizontal visibility, wind direction, gust speed and wind speed. There are four distinct seasons that can be experienced in Finland. In this thesis the seasons were defined as three-month periods, with winter consisting of December, January and February, spring consisting of March, April and May, summer consisting of June, July and August, and autumn consisting of September, October and November. The days in the weather data were classified into these seasons with a convolutional neural network model. The model included a convolutional layer followed by a fully connected layer, with the width of both layers being 16 nodes. The accuracy of the classification with this model was 0.80. The model performed better than a multinomial logistic regression model, which had accuracy of 0.75. It can be concluded that the classification task was satisfactorily successful. An interesting finding was that neither models ever confused summer and winter with each other.
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(2012)Tässä tutkielmassa tarkastellaan Cantorin joukkoa ja sen soveltamista muutamiin matemaattisiin tarkoituksiin. Cantorin joukon määrittelyssä otetaan huomioon sen monet topologiset ominaisuudet. Tarkoituksena on muotoilla Cantorin joukkoon liittyvät matemaattiset erikoisuudet mahdollisimman ymmärrettävällä tavalla matematiikkaa vain vähän opiskelleelle. Cantorin joukko on hämmentänyt matemaatikkoja sen ensimmäisestä esiintymisestä lähtien. Joukko muodostetaan vaiheittain poistamalla yksikkövälistä [0, 1] avoimia kolmanneksia. Prosessin ensimmäisessä vaiheessa välistä [0, 1] poistetaan väli (1/3, 2/3). Seuraavassa vaiheessa kahdesta välistä [0, 1/3] ja [2/3, 1] poistetaan jälleen niiden keskimmäiset kolmannekset eli välit (1/9, 2/9) ja (7/9, 8/9). Kun tätä prosessia jatketaan loputtomasti, välistä [0, 1] lopulta jäljelle jäävät pisteet muodostavat Cantorin joukon. Cantorin joukkoon kuuluvat ainakin kaikkien poistettujen välien päätepisteet. Yhtenä joukon erikoisuutena on kuitenkin se, että siihen kuuluu vielä ylinumeroituvasti ääretön määrä pisteitä, jotka eivät ole poistettujen välien päätepisteitä. Tämän seurauksena myös Cantorin joukko on siis ylinumeroituvasti ääretön. Topologiset ominaisuudet ovat Cantorin joukolla myös erikoisia. Voidaan osoittaa, että joukolla ei ole sisäpisteitä eli pisteitä, joilla olisi jokin Cantorin joukkoon kuuluva ympäristö. Lisäksi voidaan osoittaa, että jokainen Cantorin joukon piste on kasautumispiste eli piste, jonka jokaisessa ympäristössä on jokin toinen Cantorin joukon piste. Pirunporrasfunktionakin tunnetun Cantorin funktion lähtö- ja maalijoukko on yksikköväli [0, 1] eli gamma : [0, 1] -> [0, 1]. Funktion määrittely aloitetaan kuitenkin usein Cantorin joukon avulla. Nimen pirunporrasfunktio on saanut portaikkoa muistuttavasta kuvaajastaan. Vaikka gamma muistuttaa portaikkoa ja ensisilmäyksellä vaikuttaa katkonaiselta, niin se on kuitenkin jatkuva ja jopa tasaisesti jatkuva. Viimeisenä asiana tässä tutkielmassa esitetään lyhyesti Cantorin joukkoon liittyvä Lebesguen käyrä. Lebesguen käyrää sanotaan avaruuden täyttäväksi käyräksi, koska se kulkee jokaisen maalijoukkonsa, tässä tapauksessa yksikköneliön [0; 1] x [0; 1], pisteen kautta.
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(2017)In the first part of this thesis the principles of capillary electrophoresis (CE) are presented from the aspects of steroid and sterol analysis focusing mainly on two separation techniques: micellar electrokinetic chromatography (MEKC) and capillary electrochromatography (CEC). Analytes are delineated in steroids, corticosteroids, phytosterols, and cholesterol. Conventional chromatographic methods: gas chromatography (GC) and high-pressure liquid chromatography (HPLC) are somewhat challenging for steroid and sterol analysis, since direct analysis of steroids/sterols and their conjugates is rarely feasible. Hence, alternative separation and analysis methods need to be approached. MEKC and CEC have provided intriguing new opportunities for steroids and sterols, respectively. The experimental part covers the study on finding out the steroid composition and concentrations of wastewater samples collected from wastewater treatment plants (WWTP) around Finland. In addition, the efficiencies of the WWTPs were resolved. There were two types of wastewater samples: influent and effluent. Influent is the unclean water and effluent is the cleaned water that has passed through the process steps. The sample pretreatment includes filtering (glass fiber and membrane filters), solid phase extraction (SPE) (with C18 (Strata-X) and quaternary amine (N+) sorbents), and liquid-liquid extraction (LLE) (with diethyl ether). SPE was effective in purifying and concentrating the water samples, with a concentration factor of 20,000. The analysis was performed with partial filling-micellar electrokinetic chromatography, utilizing UV detection. It was found that the method was suitable for both qualitative and quantitative analysis of endogenous steroids and their corresponding metabolites. Androstenedione, testosterone glucuronide, and progesterone were found from the samples. Some notable results are that biological treatment most likely increases the amount of androstenedione, whereas enzymatic processes remove efficiently progesterone. Overall, the lowest steroid concentrations were obtained from the samples of Espoo, Pori, and Uusikaupunki. On the contrary, highest concentrations were in Kajaani, Mikkeli, and Porvoo.
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(2019)The large variety of shapes, functions, and conformations of proteins explains the challenges in protein identification and separation in solution. Gel electrophoresis, and more specifically SDS-PAGE, is an established technique applied to large proteins. Capillary gel electrophoresis offers the advantage of miniaturization coupled with higher speed of analysis and sample throughput. Protein analysis in silica capillaries is affected by the presence of charges on the silica surface, causing absorption, reliability and repeatability issues. Electroosmotic flow may also contribute, requiring buffer additives such as sodium dodecyl sulphate and dynamic or permanent coatings on the capillary wall. Coatings employed in capillary zone electrophoresis can be neutral or charged. They include copolymers such as poly((1-vinylpyrrolidone)-co-(2-dimethylaminoethyl methacrylate)), polyacrylamide, diazoresin as a coupling agent to form covalently bound coatings with polyvinyl alcohol, carboxyl fullerene and graphene oxide, and proprietary coatings. Capillary gel electrophoresis offers the advantages of a sieving matrix to enhance the separation of large proteins with similar charge-to-mass ratio. Dilute and semi-dilute polymer solutions with or without self-coating properties can be employed, such as polyacrylamide, polydimethyl acrylamide, and hydrophilic cellulose derivatives such as hydroxypropyl cellulose and hydroxyethyl cellulose. UV detection is enhanced by stacking techniques such as field-amplified sample stacking and the addition of sodium chloride to the sample. The focus of experimental laboratory works for this thesis was the identification of BSA, the lipoproteins HDL and LDL, and an apolipoprotein ApoB-100 using capillary gel electrophoresis. The polymer solution employed was cross-linked polyacrylamide. Instrumental factors such as run voltage, injection type, presence of sieving matrix and SDS in the BGE, sample concentration and presence of NaCl in the sample were examined. Repeatability was an issue throughout the study caused by current instability, although SDS in the BGE and addition of NaCl to the sample prior to injection had a positive effect. Stability of the BGE and the sieving matrix, together with addition of NaCl to the sample could be explored further.
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(2019)Tässä työssä esitellään klassinen matemaattisen rahoitusteorian aihe, Capital Asset Pricing-malli. Mallista on useita versiota, tässä työssä käsitellään Hilbertin avaruuksiin perustuvaa versiota. Yleisesti, erityisesti taloustieteen puolella, CAP-mallilla tarkoitetaan arvopapereiden hinnoittelumallia. Tässä työssä se kuitenkin määritellään tasapainotilaisten sijoituskohteiden tuottojen ominaisuutena. Hilbertin avaruudet ovat täydellisiä normiavaruuksia, jotka on varustettu sisätulolla. Esitellään Hilbertin avaruudet ja muita funktionaalianalyysin keskeisimpiä käsitteitä, kuten ortogonaalisuus ja Riesz-Frechetin teoreema, jotta CAP-mallin rakentaminen on mahdollista. Lisäksi esitellään arvopaperimarkkinat, sekä niiden toimijat. Tärkeimmät käsitteet ovat arvopapereiden tuotot ja hinnat, sekä toimijoiden kulutus ja utiliteetti. Termiä Capital Asset Pricing-malli käytetään silloin, kun markkinatuotto on odotusarvorintaman tuotto. Tällöin jokaiselle sijoituskohteelle voidaan johtaa arvopaperimarkkinasuoran yhtälö, joka on beta-hinnoittelun erikoistapaus. CAP-mallissa tuottoja mitataan odotusarvon avulla ja riskin mittarina toimii varianssi. Cap-mallin voimassaolo markkinoilla ei ole itsestäänselvyys ja liittyy läheisesti toimijoiden preferensseihin, sekä arvopapereiden voittojen jakaumaan. Lopuksi esitellään faktorimalli, joka on hyvin samankaltainen CAP-mallin kanssa.
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(2021)The number of people belonging to a language minority in Finland is increasing and people are becoming more and more spatially mobile. This has also led to an increase in transnationals and higher rates of cross-border mobility. With new methods involving social media big data, we can map spatial mobility patterns in new ways and deepen the understanding of how people relate to space. Differences in spatial mobility can for example give us an indication of the rate of integration into society. Some claim that a more spatially mobile life is a sign of success, but can we see differences in spatial mobility between people in Finland? The three language minorities considered in this thesis are Swedish, Russian, and Estonian. The history and culture of these groups are different as well as their status in Finnish society. Swedish speakers, with a national language status, have a different role in society, but do this well integrated minority differ from the other ones spatially? By using Twitter data and looking at the spatial mobility within Finland, we see where differences occur between language groups. To understand how strong ties the language groups have with neighbouring countries, we look at cross-border mobility to Estonia, Russia, and Sweden. The results show that there are differences in the spatial mobility of language minorities in Finland. Estonian speakers most frequently visit Estonia, while at the same time they are less mobile within Finland. The variation was large for Russian speakers, with some visiting Russia often and others almost never. Swedish speakers seem to have relatively weak ties to Sweden, compared to the other language groups and have very similar spatial mobility to the majority Finnish speaking population.
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(2023)Northern peatlands are important carbon storing ecosystems, contributing to carbon cycle as sinks and sources. The two most important greenhouse gases in the carbon cycle are carbon dioxide (CO2) and methane (CH4). The study area of this work consists of two sloping fens in the Kuusamo area. from which the peat geochemistry and peat properties (peat stratigraphy, ash content, and bulk density) are studied. In addition, the chronology, carbon-nitrogen ratio, carbon content, and carbon accumulation are studied in the Puukkosuo from the three sampling sites. In the characterization of peat geochemistry, Puukkosuo in the dolomitic rock area and Suvisuo in the volcanic rock area were divided into different geochemical zones based on the cluster analysis. The paludification in the Puukkosuo area has started around 10 000 years ago, and the accumulation of peat have been ongoing in the whole peat basin after 1000 years. The geochemical zones in the Puukkosuo can be divided into five different groups, from which the deepest part of the peatland basin can be separated due to the high heavy metal concentrations in the oldest peat. Most of the bulk peat is differentiated into alternating groups, from which the changes in the peat nutrients are recorded. The margins of the Puukkosuo are separated based on the geochemical properties. The top part of the northwestern edge can be characterized as high concentrations of atmospheric origin elements, whereas the effect of the nearby road can be noted in the concentrations of the top part of the southeastern edge. The amount of carbon accumulated has varied throughout the development of Puukkosuo, and the highest rates are recorded in the lower part of the peat profiles in all study sites. Highest carbon-nitrogen -ratios are recorded near the basal peat samples especially in the deepest part of the Puukkosuo. The long-term carbon accumulation differs from the other long-term averages in the boreal zone. The largest differences were recorded in the deepest part of the basin in the long-term carbon accumulation rates during the Early Holocene. The respective value in the Puukkosuo is four times higher (60 g m-2 yr-1) in contrast to others. During the Late Holocene the long-term carbon accumulation rates correspond to the other average values in the boreal peatlands (25 g m-2 yr-1).
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(2020)Urban areas account for 70% of worldwide energy-related CO2 emissions and play a significant role in the global carbon budget. With the enhanced consumption of fossil fuel and the dramatic change in land use related to urbanization, control and mitigation of CO2 emissions in the urban area is becoming a major concern for urban dwellers and city managers. It is of great importance and demand to estimate the local CO2 emissions in urban areas to assess the effectiveness of mitigation regulation. Surface Urban Energy and Water Balance Scheme (SUEWS) incorporated with a CO2 exchange module provides an advanced method to model total urban CO2 flux and quantify the different local-scale emission sectors involving transportation, human metabolism, buildings and vegetation. Using appropriate input data such as detailed site information and meteorological condition, it can simulate the local or neighbourhood scale CO2 emissions in a specific period, or even under a future scenario. In this study, the SUEWS model is implemented in an urban region, Jätkäsaari, which is an extension of Helsinki city centre, to simulate anthropogenic and biogenic CO2 emissions in the past and future. The construction of this district started in 2009 and was planned to be completed in 2030. Therefore, this region is a good case to investigate the impacts of urban planning on urban CO2 emissions. Based on the urban surface information, meteorological data, and abundant emission parameters, a simulation in this 1650 × 1400 m area with the spatial resolution of 50 × 50 m and the time resolution of an hour was conducted with the aim to get information on the total annual CO2 emissions, and the temporal and spatial variability of CO2 fluxes from different sources and sink in 2008 and 2030. The positive CO2 fluxes indicate the CO2 sources, while the negative indicate the CO2 sinks. In both of the previous and future case, the spatial variation of net CO2 fluxes in Jätkäsaari is dominated by the distribution of traffic and human activities. From April to September, the vegetation acts as the CO2 sink with negative net ecosystem exchange. In 2008, the modelled cumulative CO2 flux is 3.0 kt CO2 year-1, consisting of 1.9 kt CO2 year-1 from metabolism, 1.9 kt CO2 year-1 from traffic, 0.5 kt CO2 year-1 from soil and vegetation respiration, as well as -1.3 kt CO2 year-1 from photosynthesis. In 2030, the total annual CO2 emissions increase to 11.1 kt CO2 year-1 because of the rising traffic volume and amount of inhabitants. Road traffic became the dominant CO2 sources, accounting for 53% of the total emissions. For the diurnal variation, in 2008, the study area remains the CO2 sources with the exception of summertime morning when the net CO2 flux is negative, while in 2030, the net CO2 flux is positive in the whole day.
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(2017)In the Neoprotezoic Era (1.0Ga – 540Ma) the earth’s climate changed by multiple large glaciations and supercontinent formations and break-ups. Climate changes can be seen from the carbon isotope record, where the steep negative excursions indicate glaciation. The Neoproterozoic Era is known for the Snowball Earth events, when the earth has been covered by snow even in the equator. At the same time, there was Rodinia supercontinent break-up and continent regroup, which led to Mozambique Ocean to form and close during the East African orogen 650 – 620 Ma ago. The Taita Hills is located in South Kenya and lies in the Mozambique Belt. Taita Hills is divided into the Kurase and Kasigau groups. The Kurase group is considered to be metasediments from a continental shelf and the Kasigau group from the continental margin. The Kurase group contains multiple sedimentary carbonate rock layers, which are surveyed by Horkel et al. (1979) and offers a base for this study. The sedimentary carbonate rock samples were analysed with MP-AES for the elemental concentrations of Ca, Mg, Fe, Sr and Mn and for the δ13C and δ18O composition of carbonate. Three of the samples were calcites (Mg/Ca ratio 0.00 – 0.04) and 45 were dolomites (Mg/Ca 0.38 – 0.61). The δ13C values varies from -1.55 to 6.96‰ and the δ18O composition were between -10.2 and -0.66‰. The Mn/Sr ratio indicates that the samples have retained primary δ13C composition. The δ13C composition differs remarkably between the calcite and the dolomite samples, which might indicate that the calcite carbonates have a secondary composition even if the Mn/Sr ratio is low. The positive δ13C values represents the interglacial time. The δ13C compositions of the global δ13C record indicate that the Taita Hills region sedimentary carbonate rocks were precipitated before or after the Sturtian Snowball Earth event.
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