84 resultados para DOMAIN TRANSFER
Biophysical modeling of photosynthetic electron transfer and practical applications to cyanobacteria
Resumo:
In this thesis, the DFMA is presented and used for the purpose of having a design for a vertical transfer line that can be easily manufactured and assembled. The design of the transfer line, the major components and drawings are presented. The ease of assembly, the costs of manufacturing and differences between the use of steel structure and aluminum are compared. The ALARA principle is followed to minimize the risk of radiation exposure by the means of locating the test ion sources outside the radioactive area.
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Lipider är viktiga biomolekyler, eftersom de bygger upp alla cellulära membran. Glykolipider, dvs. lipider som innehåller socker, är dessutom betydelsefulla som signaleringsmolekyler vid olika processer. Det är essentiellt att regleringen av syntesen, nedbrytningen samt transporten av lipider i cellen är noggrant koordinerade, och faktorer som kan påverka lipidmetabolismen är därför viktiga att undersöka. Denna avhandling har undersökt två olika lipidbindande proteiner, glykolipidtransportprotein (GLTP) och ceramidtransportprotein (CERT). GLTPs biologiska funktion är ännu oklar, dock vet man att GLTP har förmåga att binda olika glykolipider samt överföra dessa lipider mellan olika lipidmembraner. CERT har däremot visats kunna transportera ceramid från det endoplastiska retiklet (ER) till Golgi-apparaten, för produktion av sfingomyelin. I detta avhandlingsarbete undersöktes lokaliseringen av GLTP i celler med olika metoder, bl.a. konfokalmikroskopi, samt olika centrifugeringsmetoder. Genom att överuttrycka GLTP i celler och därefter analysera halten nysyntetiserade glykolipider, kunde även sambandet mellan GLTP-uttrycket och dessa lipider undersökas. I avhandlingen identifierades ytterligare en specifik aminosyrasekvens hos GLTP. Denna sekvens visades kunna binda till VAP-A, ett integralt ER protein, med en tidigare fastställd viktig funktion vid regleringen av lipidtransporten. I avhandlingen analyserades även hur ceramidtransporten mellan två olika membraner, medierad av CERT, påverkas av egenskaper i ceramidens omgivning. För att undersöka detta användes artificiella modellmembraner samt fluorimetriska metoder. Sammansättningen och packningen hos lipidmembranerna visades ha en stor betydelse för den CERT-katalyserade ceramidtransporten. Sammanfattningsvis antyder resultaten från avhandlingen att det existerar flera faktorer som kan påverka aktiviteten av GLTP och CERT, vilka i sin tur har förmåga att reglera lipidmetabolismen.
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The paper is devoted to study specific aspects of heat transfer in the combustion chamber of compression ignited reciprocating internal combustion engines and possibility to directly measure the heat flux by means of Gradient Heat Flux Sensors (GHFS). A one – dimensional single zone model proposed by Kyung Tae Yun et al. and implemented with the aid of Matlab, was used to obtain approximate picture of heat flux behavior in the combustion chamber with relation to the crank angle. The model’s numerical output was compared to the experimental results. The experiment was accomplished by A. Mityakov at four stroke diesel engine Indenor XL4D. Local heat fluxes on the surface of cylinder head were measured with fast – response, high – sensitive GHFS. The comparison of numerical data with experimental results has revealed a small deviation in obtained heat flux values throughout the cycle and different behavior of heat flux curve after Top Dead Center.
Resumo:
This thesis focuses on the molecular mechanisms regulating the photosynthetic electron transfer reactions upon changes in light intensity. To investigate these mechanisms, I used mutants of the model plant Arabidopsis thaliana impaired in various aspects of regulation of the photosynthetic light reactions. These included mutants of photosystem II (PSII) and light harvesting complex II (LHCII) phosphorylation (stn7 and stn8), mutants of energy-dependent non-photochemical quenching (NPQ) (npq1 and npq4) and of regulation of photosynthetic electron transfer (pgr5). All of these processes have been extensively investigated during the past decades, mainly on plants growing under steady-state conditions, and therefore many aspects of acclimation processes may have been neglected. In this study, plants were grown under fluctuating light, i.e. the alternation of low and high intensities of light, in order to maximally challenge the photosynthetic regulatory mechanisms. In pgr5 and stn7 mutants, the growth in fluctuating light condition mainly damaged PSI while PSII was rather unaffected. It is shown that the PGR5 protein regulates the linear electron transfer: it is essential for the induction of transthylakoid ΔpH that, in turn, activates energy-dependent NPQ and downregulates the activity of cytochrome b6f. This regulation was shown to be essential for the photoprotection of PSI under fluctuations in light intensity. The stn7 mutants were able to acclimate under constant growth light conditions by modulating the PSII/PSI ratio, while under fluctuating growth light they failed in implementing this acclimation strategy. LHCII phosphorylation ensures the balance of the excitation energy distribution between PSII and PSI by increasing the probability for excitons to be trapped by PSI. LHCII can be phosphorylated over all of the thylakoid membrane (grana cores as well as stroma lamellae) and when phosphorylated it constitutes a common antenna for PSII and PSI. Moreover, LHCII was shown to work as a functional bridge that allows the energy transfer between PSII units in grana cores and between PSII and PSI centers in grana margins. Consequently, PSI can function as a quencher of excitation energy. Eventually, the LHCII phosphorylation, NPQ and the photosynthetic control of linear electron transfer via cytochrome b6f work in concert to maintain the redox poise of the electron transfer chain. This is a prerequisite for successful plant growth upon changing natural light conditions, both in short- and long-term.
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Information gained from the human genome project and improvements in compound synthesizing have increased the number of both therapeutic targets and potential lead compounds. This has evolved a need for better screening techniques to have a capacity to screen number of compound libraries against increasing amount of targets. Radioactivity based assays have been traditionally used in drug screening but the fluorescence based assays have become more popular in high throughput screening (HTS) as they avoid safety and waste problems confronted with radioactivity. In comparison to conventional fluorescence more sensitive detection is obtained with time-resolved luminescence which has increased the popularity of time-resolved fluorescence resonance energy transfer (TR-FRET) based assays. To simplify the current TR-FRET based assay concept the luminometric homogeneous single-label utilizing assay technique, Quenching Resonance Energy Transfer (QRET), was developed. The technique utilizes soluble quencher to quench non-specifically the signal of unbound fraction of lanthanide labeled ligand. One labeling procedure and fewer manipulation steps in the assay concept are saving resources. The QRET technique is suitable for both biochemical and cell-based assays as indicated in four studies:1) ligand screening study of β2 -adrenergic receptor (cell-based), 2) activation study of Gs-/Gi-protein coupled receptors by measuring intracellular concentration of cyclic adenosine monophosphate (cell-based), 3) activation study of G-protein coupled receptors by observing the binding of guanosine-5’-triphosphate (cell membranes), and 4) activation study of small GTP binding protein Ras (biochemical). Signal-to-background ratios were between 2.4 to 10 and coefficient of variation varied from 0.5 to 17% indicating their suitability to HTS use.
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Background: Lymphedema is a debilitating disorder with few treatment options. Clinical studies have shown that microvascular lymph node transfer may improve the lymphatic function of the affected limb. This study provides information about the clinical efficacy and safety of this procedure. Further, the biological background of this technique is clarified with an analysis of postoperative production of lymphatic growth factors and cytokines related to lymphangiogenesis. Patients and Methods: The effect of lymph node transfer to recipient and donor sites was analyzed with lymphoscintigraphy, limb circumference measurements, and appearance of clinical symptoms. Axillary seroma samples were analyzed from four patient groups: Axillary lymph node removal (ALND), Microvascular breast reconstruction (BR), lymph node transfer (LN) and combined lymph node transfer and breast reconstruction (LN-BR). Results: The postoperative lymphatic transport index was improved in 7/19 patients. Ten patients were able to reduce or discontinue compression therapy 6 - 24 months postoperatively. The donor lower limb lymphatic flow was slightly impaired (Ti >10) in 2 patients. No donor site lymphedema symptoms appeared during the 8 – 56-month follow-up. A high concentration of the VEGF-C protein was detected in the seroma fluid of all flap transfer groups. The concentration of the anti-inflammatory and anti-fibrotic cytokine IL-10 was increased in the LN-BR group samples when compared to the ALND or BR group. Conclusions: According to this preliminary study, the lymph node transfer seems to be beneficial for the lymphedema patients. However, a randomized study comparing the effect of BR and LN-BR is needed to evaluate the clinical efficacy of lymph node transfer. In addition, the effect of this surgery on the donor site needs to be studied further. The clinical effects of the lymph node transfer might be partly mediated by increased production of the lymphangiogenic growth factor (VEGF-C) as well as the anti-fibrotic cytokine (IL-10).
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Tankyrases belong to the Diphtheria toxin-like ADP-ribosyltransferase (ARTD) enzyme superfamily, also known as poly(ADP-ribose) polymerases (PARPs). They catalyze a covalent post-translational modification reaction where they transfer ADP-ribose units from NAD+ to target proteins. Tankyrases are involved in many cellular processes and their roles in telomere homeostasis, Wnt signaling and in several diseases including cancers have made them interesting drug targets. In this thesis project, selective inhibition of human tankyrases was studied. A homogeneous fluorescence-based assay was developed to screen the compound libraries. The assay is inexpensive, operationally easy, and performs well according to the statistical analysis. Assay suitability was confirmed by screening a natural product library. Flavone was identified as the most potent inhibitor in the library and this motivated us to screen a larger flavonoid library. Results showed that flavones were indeed the best inhibitor of tankyrases among flavonoids. To further study the structure-activity relationship, a small library of flavones containing single substitution was screened and potency measurements allowed us to generate structure-activity relationship. Compounds containing substitutions at 4´-position were more potent in comparison to other substitutions, and importantly, hydrophobic groups improved isoenzyme selectivity as well as the potency. A flavone derivative containing a hydrophobic isopropyl group (compound 22), displayed 6 nM potency against TNKS1, excellent isoenzyme selectivity and Wnt signaling inhibition. Protein interactions with compounds were studied by solving complex crystal structures of the compounds with TNKS2 catalytic domain. A novel tankyrase inhibitor (IWR-1) was also crystallized in complex with TNKS2 catalytic domain. The crystal structure of TNKS2 in complex with IWR-1 showed that the compound binds to adenosine site and it was the first known ARTD inhibitor of this kind. To date, there is no structural information available about the substrate binding with any of the ARTD family members; therefore NAD+ was soaked with TNKS2 catalytic domain crystals. However, analysis of crystal structure showed that NAD+ was hydrolyzed to nicotinamide. Also, a co-crystal structure of NAD+ mimic compound, EB-47, was solved which was used to deduce some insights about the substrate interactions with the enzyme. Like EB-47, other ARTD1 inhibitors were also shown to inhibit tankyrases. It indicated that selectivity of the ARTD1 inhibitors should be considered as some of the effects in cells could come from tankyrase inhibition. In conclusion, the study provides novel information on tankyrase inhibition and presents new insight into the selectivity and potency of compounds.
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This Master’s Thesis deals with the topic of transfer pricing documentation in Finland and China. The goal of the research is to find what kind of differences exist in a single case company’s transfer pricing documentation when following Chinese or Finnish transfer pricing regulations. The study is carried out as a case study research. The theoretical framework consists of information from different transfer pricing topics and transfer pricing documentation regulations in China and Finland. The main research material was the case company’s transfer pricing documents with the support of open discus-sion with one of the case company’s employees. The study compared the 2009 and 2010 documents. The 2009 document was done based on the Finnish method while the 2010 document was based on the Chinese documentation principles. The conclusion made is that the content of the documents was heavily similar, while the main differences come in the way the content is presented and the level of detail used in the documents.
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The purpose of this thesis is to study the international technology transfer of transition economy SME entrepreneurs to the developed countries. The research aims to characterize the phenomenon by studying Russian SME technology transfer to Finland with the research methods from case studies. In addition to characterizing the phenomenon, the research finds out factors that motivate Russian entrepreneurs to conduct international technology transfer and what are the challenges the Russian entrepreneurs face when they enter the Finnish business environment. The qualitative data was collected from six semi-structured interviews with the entrepreneurs and several secondary data sources, considering four different technology transfer cases. The data and the analysis showed that the case companies in Finland are mostly linked to manufacturing of physical products. The entrepreneurs are motivated to come to Finland mainly by the opportunities and support the Finnish business and innovation environment provides to the entrepreneurs and by the personal gain that they get by establishing the company in Finland. Major challenges in the process include time constraints and capital requirements, difficulties on achieving sales on the Finnish market and finding skilled personnel to support the Russian management and owners.
Resumo:
This thesis aims to find an effective way of conducting a target audience analysis (TAA) in cyber domain. There are two main focal points that are addressed; the nature of the cyber domain and the method of the TAA. Of the cyber domain the object is to find the opportunities, restrictions and caveats that result from its digital and temporal nature. This is the environment in which the TAA method is examined in this study. As the TAA is an important step of any psychological operation and critical to its success, the method used must cover all the main aspects affecting the choice of a proper target audience. The first part of the research was done by sending an open-ended questionnaire to operators in the field of information warfare both in Finland and abroad. As the results were inconclusive, the research was completed by assessing the applicability of United States Army Joint Publication FM 3-05.301 in the cyber domain via a theory-based content analysis. FM 3- 05.301 was chosen because it presents a complete method of the TAA process. The findings were tested against the results of the questionnaire and new scientific research in the field of psychology. The cyber domain was found to be “fast and vast”, volatile and uncontrollable. Although governed by laws to some extent, the cyber domain is unpredictable by nature and not controllable to reasonable amount. The anonymity and lack of verification often present in the digital channels mean that anyone can have an opinion, and any message sent may change or even be counterproductive to the original purpose. The TAA method of the FM 3-05.301 is applicable in the cyber domain, although some parts of the method are outdated and thus suggested to be updated if used in that environment. The target audience categories of step two of the process were replaced by new groups that exist in the digital environment. The accessibility assessment (step eight) was also redefined, as in the digital media the mere existence of a written text is typically not enough to convey the intended message to the target audience. The scientific studies made in computer sciences and both in psychology and sociology about the behavior of people in social media (and overall in cyber domain) call for a more extensive remake of the TAA process. This falls, however, out of the scope of this work. It is thus suggested that further research should be carried out in search of computer-assisted methods and a more thorough TAA process, utilizing the latest discoveries of human behavior. ---------------------------------------------------------------------------------------------------------------------------------- Tämän opinnäytetyön tavoitteena on löytää tehokas tapa kohdeyleisöanalyysin tekemiseksi kybertoimintaympäristössä. Työssä keskitytään kahteen ilmiöön: kybertoimintaympäristön luonteeseen ja kohdeyleisöanalyysin metodiin. Kybertoimintaympäristön osalta tavoitteena on löytää sen digitaalisesta ja ajallisesta luonteesta juontuvat mahdollisuudet, rajoitteet ja sudenkuopat. Tämä on se ympäristö jossa kohdeyleisöanalyysiä tarkastellaan tässä työssä. Koska kohdeyleisöanalyysi kuuluu olennaisena osana jokaiseen psykologiseen operaatioon ja on onnistumisen kannalta kriittinen tekijä, käytettävän metodin tulee pitää sisällään kaikki oikean kohdeyleisön valinnan kannalta merkittävät osa-alueet. Tutkimuksen ensimmäisessä vaiheessa lähetettiin avoin kysely informaatiosodankäynnin ammattilaisille Suomessa ja ulkomailla. Koska kyselyn tulokset eivät olleet riittäviä johtopäätösten tekemiseksi, tutkimusta jatkettiin tarkastelemalla Yhdysvaltojen armeijan kenttäohjesäännön FM 3-05.301 soveltuvuutta kybertoimintaympäristössä käytettäväksi teorialähtöisen sisällönanalyysin avulla. FM 3-05.301 valittiin koska se sisältää kokonaisvaltaisen kohdeyleisöanalyysiprosessin. Havaintoja verrattiin kyselytutkimuksen tuloksiin ja psykologian uusiin tutkimuksiin. Kybertoimintaympäristö on tulosten perusteella nopea ja valtava, jatkuvasti muuttuva ja kontrolloimaton. Vaikkakin lait hallitsevat kybertoimintaympäristöä jossakin määrin, on se silti luonteeltaan ennakoimaton eikä sitä voida luotettavasti hallita. Digitaalisilla kanavilla usein läsnäoleva nimettömyys ja tiedon tarkastamisen mahdottomuus tarkoittavat että kenellä tahansa voi olla mielipide asioista, ja mikä tahansa viesti voi muuttua, jopa alkuperäiseen tarkoitukseen nähden vastakkaiseksi. FM 3-05.301:n metodi toimii kybertoimintaympäristössä, vaikkakin jotkin osa-alueet ovat vanhentuneita ja siksi ne esitetään päivitettäväksi mikäli metodia käytetään kyseisessä ympäristössä. Kohdan kaksi kohdeyleisökategoriat korvattiin uusilla, digitaalisessa ympäristössä esiintyvillä ryhmillä. Lähestyttävyyden arviointi (kohta 8) muotoiltiin myös uudestaan, koska digitaalisessa mediassa pelkkä tekstin läsnäolo ei sellaisenaan tyypillisesti vielä riitä halutun viestin välittämiseen kohdeyleisölle. Tietotekniikan edistyminen ja psykologian sekä sosiologian aloilla tehty tieteellinen tutkimus ihmisten käyttäytymisestä sosiaalisessa mediassa (ja yleensä kybertoimintaympäristössä) mahdollistavat koko kohdeyleisöanalyysiprosessin uudelleenrakentamisen. Tässä työssä sitä kuitenkaan ei voida tehdä. Siksi esitetäänkin että lisätutkimusta tulisi tehdä sekä tietokoneavusteisten prosessien että vielä syvällisempien kohdeyleisöanalyysien osalta, käyttäen hyväksi viimeisimpiä ihmisen käyttäytymiseen liittyviä tutkimustuloksia.
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The main objective of this research is to estimate and characterize heterogeneous mass transfer coefficients in bench- and pilot-scale fluidized bed processes by the means of computational fluid dynamics (CFD). A further objective is to benchmark the heterogeneous mass transfer coefficients predicted by fine-grid Eulerian CFD simulations against empirical data presented in the scientific literature. First, a fine-grid two-dimensional Eulerian CFD model with a solid and gas phase has been designed. The model is applied for transient two-dimensional simulations of char combustion in small-scale bubbling and turbulent fluidized beds. The same approach is used to simulate a novel fluidized bed energy conversion process developed for the carbon capture, chemical looping combustion operated with a gaseous fuel. In order to analyze the results of the CFD simulations, two one-dimensional fluidized bed models have been formulated. The single-phase and bubble-emulsion models were applied to derive the average gas-bed and interphase mass transfer coefficients, respectively. In the analysis, the effects of various fluidized bed operation parameters, such as fluidization, velocity, particle and bubble diameter, reactor size, and chemical kinetics, on the heterogeneous mass transfer coefficients in the lower fluidized bed are evaluated extensively. The analysis shows that the fine-grid Eulerian CFD model can predict the heterogeneous mass transfer coefficients quantitatively with acceptable accuracy. Qualitatively, the CFD-based research of fluidized bed process revealed several new scientific results, such as parametrical relationships. The huge variance of seven orders of magnitude within the bed Sherwood numbers presented in the literature could be explained by the change of controlling mechanisms in the overall heterogeneous mass transfer process with the varied process conditions. The research opens new process-specific insights into the reactive fluidized bed processes, such as a strong mass transfer control over heterogeneous reaction rate, a dominance of interphase mass transfer in the fine-particle fluidized beds and a strong chemical kinetic dependence of the average gas-bed mass transfer. The obtained mass transfer coefficients can be applied in fluidized bed models used for various engineering design, reactor scale-up and process research tasks, and they consequently provide an enhanced prediction accuracy of the performance of fluidized bed processes.
Resumo:
The aim of the work presented in this study was to demonstrate the wide applicability of a single-label quenching resonance energy transfer (QRET) assay based on time-resolved lanthanide luminescence. QRET technology is proximity dependent method utilizing weak and unspecific interaction between soluble quencher molecule and lanthanide chelate. The interaction between quencher and chelate is lost when the ligand binds to its target molecule. The properties of QRET technology are especially useful in high throughput screening (HTS) assays. At the beginning of this study, only end-point type QRET technology was available. To enable efficient study of enzymatic reactions, the QRET technology was further developed to enable measurement of reaction kinetics. This was performed using proteindeoxyribonuclei acid (DNA) interaction as a first tool to monitor reaction kinetics. Later, the QRET was used to study nucleotide exchange reaction kinetics and mutation induced effects to the small GTPase activity. Small GTPases act as a molecular switch shifting between active GTP bound and inactive GDP bound conformation. The possibility of monitoring reaction kinetics using the QRET technology was evaluated using two homogeneous assays: a direct growth factor detection assay and a nucleotide exchange monitoring assay with small GTPases. To complete the list, a heterogeneous assay for monitoring GTP hydrolysis using small GTPases, was developed. All these small GTPase assays could be performed using nanomolar protein concentrations without GTPase pretreatment. The results from these studies demonstrated that QRET technology can be used to monitor reaction kinetics and further enable the possibility to use the same method for screening.
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Alfa Laval Aalborg Oy designs and manufactures waste heat recovery systems utilizing extended surfaces. The waste heat recovery boiler considered in this thesis is a water-tube boiler where exhaust gas is used as the convective heat transfer medium and water or steam flowing inside the tubes is subject to cross-flow. This thesis aims to contribute to the design of waste heat recovery boiler unit by developing a numerical model of the H-type finned tube bundle currently used by Alfa Laval Aalborg Oy to evaluate the gas-side heat transfer performance. The main objective is to identify weaknesses and potential areas of development in the current H-type finned tube design. In addition, numerical simulations for a total of 15 cases with varying geometric parameters are conducted to investigate the heat transfer and pressure drop performance dependent on H-type fin geometry. The investigated geometric parameters include fin width and height, fin spacing, and fin thickness. Comparison between single and double tube type configuration is also conducted. Based on the simulation results, the local heat transfer and flow behaviour of the H-type finned tube is presented including boundary layer development between the fins, the formation of recirculation zone behind the tubes, and the local variations of flow velocity and temperature within the tube bundle and on the fin surface. Moreover, an evaluation of the effects of various fin parameters on heat transfer and pressure drop performance of H-type finned tube bundle has been provided. It was concluded that from the studied parameters fin spacing and fin width had the most significant effect on tube bundle performance and the effect of fin thickness was the least important. Furthermore, the results suggested that the heat transfer performance would increase due to enhanced turbulence if the current double tube configuration is replaced with single tube configuration, but further investigation and experimental measurements are required in order to validate the results.