26 resultados para ZnO:Ga
em Doria (National Library of Finland DSpace Services) - National Library of Finland, Finland
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Painovuosi nimekkeestä.
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Geokemi och isotopsammansättningarna hos ca 1,8 Ga (miljarder år) gamla mafiska bergartsintrusioner studerades i två huvudområden: i) Transskandinaviska magmatiska bältet (TMB) i Bergslagen, Småland och Blekinge, södra Sverige, inklusive några prov från det ca 1,87 Ga gamla Hedesunda-komplexet i östra Bergslagen, samt ii) mindre, postkollisionala komplex i södra Finland och ryska Karelen. I det senare fallet var även tillhörande granitoider inkluderade i studierna. TMB-bergarterna skiljer sig avsevärt i utvecklingsgrad och omfattar sammansättningsmässigt bergarter från ultramafiter till kvartsdioriter. Dessa bergarters geokemi är kännetecknande för kontinentala öbågar. För sydligaste TMB och Hedesunda antyder geokemin en något mera oceanisk öbågekaraktär. Tillsammans med tidigare data antyder de av Rutanen analyserade Nd- och Sr-isotopförhållanden för TMB en ’milt utarmad’ mantelsammansättning. De mafiska bergarterna i södra Finland och ryska Karelen varierar från ultramafiska till monzodioritiska, men med avsevärt högre alkalihalter jämfört med TMB. Källan för all den studerade mafiska magmatismen kan beskrivas som en utarmad mantel som i varierande grad påverkats av fluider och smältor ur subducerande litosfärplattor. Geokemin antyder infiltrering och påverkning av H2O-dominerande fluider i övre manteln för TMB. Den mafiska ca 1,8 Ga gamla magmatismen österut avspeglar en ökande påverkan av sedimentderiverade karbonatfluider och smältor inom allt djupare mantelområden. Denna subduktionsrelaterade mantelanrikning skedde under den föregående öbågeutvecklingen i södra delarna av Finland och Sverige, samt ryska Karelen. Geokemin för en grupp granitoider, associerade med de ca 1,8 Ga gamla intrusionerna i södra Finland visar både vulkanisk öbåge och synkollisional granitoidkaraktär. Denna grupp har ett blandat magmatiskt och sedimentärt Svekofenniskt ursprung, vilket kan antas p.g.a. deras Nd- och Sr-isotopförhållanden. En annan grupp av granitoider ligger geokemiskt mellan vulkanisk öbåge- och intraplatt-granitoider, och har magmatiskt ursprung. Geokemin och isotoperna hos dessa intrusioner kan förklaras med hybridisering mellan de kraftigt anrikade, mantelderiverade magmorna, och granitmagmor från den äldre skorpan. Den ca 1,8 Ga gamla TMB-magmatismen i Sverige skedde vid sammanslutning av kontinentalrandbågar, med kontinuerlig subduktion mot öster i Bergslagen, och mot norr i de sydligare delarna. Samtidigt i öster intruderade de postkollisionala intrusionerna i skorpan omedelbart efter kollisionen med den Volgo-Sarmatiska kontinenten från sydost. Denna invecklade paleotektoniska konfiguration orsakade en tektonisk regim där litosfäriska mantelkällor levererade de starkt anrikade magmorna, vilkas uppstigning troligen möjliggjordes av djupgående postkollisionala skjuvzoner. Intrusionerna orsakade uppsmältning av den omgivande skorpan, vilket framkallade den associerade granitoidmagmatismen.
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Asthma and allergy are common diseases and their prevalence is increasing. One of the hypotheses that explains this trend is exposure to inhalable chemicals such as traffi c-related air pollution. Epidemiological research supports this theory, as a correlation between environmental chemicals and allergic respiratory diseases has been found. In addition to ambient airborne particles, one may be exposed to engineered nanosized materials that are actively produced due to their favorable physico-chemical properties compared to their bulk size counterparts. On the cellular level, improper activity of T helper (Th) cells has been connected to allergic reactions. Th cells can differentiate into functionally different effector subsets, which are identifi ed according to their characteristic cytokine profi les resulting in specifi c ability to communicate with other cells. Th2 cells activate humoral immunity and stimulate eradication of extracellular pathogens. However, persistent predominance of Th2 cells is involved in a development of number of allergic diseases. The cytokine environment at the time of antigen recognition is the major factor determining the polarization of a naïve Th cell. Th2 cell differentiation is initiated by IL4, which signals via transcription factor STAT6. Although the importance of this pathway has been evaluated in the mouse studies, the signaling components involved have been largely unknown. The aim of this thesis was to identify molecules, which are under the control of IL4 and STAT6 in Th cells. This was done by using system-level analysis of STAT6 target genes at genome, mRNA and protein level resulting in identifi cation of various genes previously not connected to Th2 cell phenotype acquisition. In the study, STAT6-mediated primary and secondary target genes were dissection from each other and a detailed transcriptional kinetics of Th2 cell polarization of naïve human CD4+ T cells was collected. Integration of these data revealed the hierarchy of molecular events that mediates the differentiation towards Th2 cell phenotype. In addition, the results highlighted the importance of exploiting proteomics tools to complement the studies on STAT6 target genes identifi ed through transcriptional profi ling. In the last subproject, the effects of the exposure with ZnO and TiO2 nanoparticles was analyzed in Jurkat T cell line and in primary human monocyte-derived macrophages and dendritic cells to evaluate their toxicity and potential to cause infl ammation. Identifi cation of ZnO-derived gene expression showed that the same nanoparticles may elicit markedly distinctive responses in different cell types, thus underscoring the need for unbiased profi ling of target genes and pathways affected. The results gave additional proof that the cellular response to nanosized ZnO is due to leached Zn2+ ions. The approach used in ZnO and TiO2 nanoparticle study demonstrated the value of assessing nanoparticle responses through a toxicogenomics approach. The increased knowledge of Th2 cell signaling will hopefully reveal new therapeutic nodes and eventually improve our possibilities to prevent and tackle allergic infl ammatory diseases.
First-principles study on electronic and structural properties of Cu(In/Ga)Se alloys for solar cells
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Thin-film photovoltaic solar cells based on the Cu(In1−xGax)Se2 (CIGS) alloys have attracted more and more attention due to their large optical absorption coefficient, long term stability, low cost, and high efficiency. Modern theoretical studies of this material with first-principles calculations can provide accurate description of the electronic structure and yield results in close agreement with experimental values, but takes a large amount of calculation time. In this work, we use first-principles calculations based on the computationally affordable meta- generalized gradient approximation of the density-functional theory to investigate electronic and structural properties of the CIGS alloys. We report on the simulation of the lattice parameters and band gaps, as a function of chemical composition. The obtained results were found to be in a good agreement with the available experimental data.
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Traditional methods for studying the magnetic shape memory (MSM) alloys Ni-Mn-Ga include subjecting the entire sample to a uniform magnetic field or completely actuating the sample mechanically. These methods have produced significant results in characterizing the MSM effect, the properties of Ni-Mn-Ga and have pioneered the development of applications from this material. Twin boundaries and their configuration within a Ni-Mn-Ga sample are a key component in the magnetic shape memory effect. Applications that are developed require an understanding of twin boundary characteristics and, more importantly, the ability to predictably control them. Twins have such a critical role that the twinning stress of a Ni-Mn-Ga crystal is the defining characteristic that indicates its quality and significant research has been conducted to minimize this property. This dissertation reports a decrease in the twinning stress, predictably controlling the twin configuration and characterizing the dynamics of twin boundaries. A reduction of the twinning stress is demonstrated by the discovery of Type II twins within Ni-Mn-Ga which have as little as 10% of the twinning stress of traditional Type I twins. Furthermore, new methods of actuating a Ni-Mn-Ga element using localized unidirectional or bidirectional magnetic fields were developed that can predictably control the twin configuration in a localized area of a Ni-Mn-Ga element. This method of controlling the local twin configuration was used in the characterization of twin boundary dynamics. Using a localized magnetic pulse, the velocity and acceleration of a single twin boundary were measured to be 82.5 m/s and 2.9 × 107 m/s2, and the time needed for the twin boundary to nucleate and begin moving was less than 2.8 μs. Using a bidirectional magnetic field from a diametrically magnetized cylindrical magnet, a highly reproducible and controllable local twin configuration was created in a Ni-Mn-Ga element which is the fundamental pumping mechanism in the MSM micropump that has been co-invented and extensively characterized by the author.
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Background Multiple sclerosis (MS) is a demyelinating disease of the central nervous system, which mainly affects young adults. In Finland, approximately 2500 out of 6000 MS patients have relapsing MS and are treated with disease modifying drugs (DMD): interferon- β (INF-β-1a or INF-β-1b) and glatiramer acetate (GA). Depending on the used IFN-β preparation, 2 % to 40 % of patients develop neutralizing antibodies (NAbs), which abolish the biological effects of IFN-β, leading to reduced clinical and MRI detected efficacy. According to the Finnish Current Care Guidelines and European Federation of Neurological Societis (EFNS) guidelines, it is suggested tomeasure the presence of NAbs during the first 24 months of IFN-β therapy. Aims The aim of this thesis was to measure the bioactivity of IFN-β therapy by focusing on the induction of MxA protein (myxovirus resistance protein A) and its correlation to neutralizing antibodies (NAb). A new MxA EIA assay was set up to offer an easier and rapid method for MxA protein detection in clinical practice. In addition, the tolerability and safety of GA were evaluated in patients who haddiscontinued IFN-β therapy due to side effects and lack of efficacy. Results NAbs developed towards the end of 12 months of treatment, and binding antibodies were detectable before or parallel with them. The titer of NAb correlated negatively with the amount of MxA protein and the mean values of preinjection MxA levels never returned to true baseline in NAb negative patients, but tended to drop in the NAb positive group. The test results between MxA EIA and flow cytometric analysis showed significant correlation. GA reduced the relapse rate and was a safe and well-tolerated therapy in IFN-β-intolerant MS patients. Conclusions NAbs inhibit the induction of MxA protein, which can be used as a surrogate marker of the bioactivity of IFN-β therapy. Compared to flow cytometricanalysis and NAb assay, MxA-EIA seemed to be a sensitive and more practical method in clinical use to measure the actual bioactivity of IFN-β treatment, which is of value also from a cost-effective perspective.
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Tässä diplomityössä tutkittiin painetun paperin ja siitä fenoliformaldehydihartsilla impregnoimalla valmistetun pinnoituskalvon UV-stabiilisuuden parantamis-mahdollisuuksia. Työn kirjallisuusosassa käsitellään painetun pinnoituskalvon valmistusprosessia ja painatuksen UV-valonkestoon vaikuttavia tekijöitä. Painovärin pigmentti, sen määrä ja käsittely, painovärin sideaine sekä fenoliformaldehydihartsi ja sen lisäaineet vaikuttavat pinnoitetun betonoimisvanerin säänkesto-ominaisuuksiin. Erilaisilla epäorgaanisilla valkoisilla pigmenteillä ja kidemuodoilla on erilainen UV-valonkesto ja taitekerroin. Päällystämällä titaanidioksidi esimerkiksi alumiini- tai zirkoniumoksideilla sen UV-valonkestoa voidaan parantaa merkittävästi. UV-hajoaminen voidaan havaita painetun pinnoitteen liituuntumisena. Liituuntumista voidaan pitää veden ja hapen välisenä reaktiona, jota titaanidioksidi ja UV-säteily katalysoivat. Sen takia myös muiden valkoisten epäorgaanisten pigmenttien ominaisuuksia ja käyttöä selvitettiin. Kokeissa käytettiin yhdeksää eri painoväriä, kahta eri paksuista paperia ja kahta eri tyyppistä hartsia. Painovärejä ohennettiin vedellä ja paperin painopuolta vaihdeltiin. Kaikissa painatuksissa käytettiin kolmea eri rasterointiasteen laattaa, jolloin painovärin määrää paperissa saatiin vähennettyä. Painetuista papereista mitattiin densiteetti, värimäärä, pisara-absorptio vedellä ja kontaktikulma hartsilla. Myös painovärin tunkeumaa selvitettiin paperin poikkileikeistä tehtyjen SEM-kuvien avulla. Painetut paperit impregnoitiin fenoliformaldehydihartsilla kalvoksi. Pinnoituskalvot puristettiin vanerin pinnalle laboratoriopuristimella. Koekappaleet altistettiin UV-valolle, sateelle ja pakkaselle sääkaapissa 400 h ajan, mikä vastaa noin 1,5 vuotta ulkona Suomen oloissa. Kappaleista mitattiin kiilto, värinmuutos ja liituuntuminen. Pinnoitteen liituuntumista tapahtui vähiten niissä koepisteissä, joissa painatus oli tehty 30 % rasteroidulla laatallaSäänkestävä TiO2 osoittautui hyväksi, mutta myös ZnO-pigmentillä saatiin hyviä tuloksia. ZnO-koepisteessä liituuntumisreaktio ei ole niin voimakkaasti katalysoitu kuin TiO2-koepisteissä. Paksun paperin painatuspuolella näytti olevan merkitystä säänkestoon. Huopapuolelle painettuna pinnoitteen liituuntuminen oli vähäisempää
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The aim of this study is to gain a better understanding of the structure and the deformation history of a NW-SE trending regional, crustal-scale shear structure in the Åland archipelago, SW Finland, called the Sottunga-Jurmo shear zone (SJSZ). Approaches involving e.g. structural geology, geochronology, geochemistry and metamorphic petrology were utilised in order to reconstruct the overall deformation history of the study area. The study therefore describes several features of the shear zone including structures, kinematics and lithologies within the study area, the ages of the different deformation phases (ductile to brittle) within the shear zone, as well as some geothermobarometric results. The results indicate that the SJSZ outlines a major crustal discontinuity between the extensively migmatized rocks NE of the shear zone and the unmigmatised, amphibolite facies rocks SW of the zone. The main SJSZ shows overall dextral lateral kinematics with a SW-side up vertical component and deformation partitioning into pure shear and simple shear dominated deformation styles that was intensified toward later stages of the deformation history. The deformation partitioning resulted in complex folding and refolding against the SW margin of the SJSZ, including conical and sheath folds, and in a formation of several minor strike-slip shear zones both parallel and conjugate to the main SJSZ in order to accommodate the regional transpressive stresses. Different deformation phases within the study area were dated by SIMS (zircon U-Pb), ID-TIMS (titanite U-Pb) and 40Ar/39Ar (pseudotachylyte wholerock) methods. The first deformation phase within the ca. 1.88 Ga rocks of the study area is dated at ca. 1.85 Ga, and the shear zone was reactivated twice within the ductile regime (at ca. 1.83 Ga and 1.79 Ga), during which the strain was successively increasingly partitioned into the main SJSZ and the minor shear zones. The age determinations suggest that the orogenic processes within the study area did not occur in a temporal continuum; instead, the metamorphic zircon rims and titanites show distinct, 10-20 Ma long breaks in deformation between phases of active deformation. The results of this study further imply slow cooling of the rocks through 600-700ºC so that at 1.79 Ga, 2 the temperature was still at least 600ºC. The highest recorded metamorphic pressures are 6.4-7.1 kbar. At the late stages or soon after the last ductile phase (ca. 1.79 Ga), relatively high-T mylonites and ultramylonites were formed, witnessing extreme deformation partitioning and high strain rates. After the rocks reached lower amphibolite facies to amphibolite-greenschist facies transitional conditions (ca. 500-550ºC), they cooled rapidly, probably due to crustal uplift and exhumation. The shear zone was reactivated at least once within the semi-brittle to brittle regime between ca. 1.79 Ga and 1.58 Ga, as evidenced by cataclasites and pseudotachylytes. In summary, the results of this study suggest that the Sottunga-Jurmo shear zone (and the South Finland shear zone) defines a major crustal discontinuity, and played a central role in accommodating the regional stresses during and after the Svecofennian orogeny.
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The goal of the thesis was to study fundamental structural and optical properties of InAs islands and In(Ga)As quantum rings. The research was carried out at the Department of Micro and Nanosciences of Helsinki University of Technology. A good surface quality can be essential for the potential applications in optoelectronic devices. For such device applications it is usually necessary to control size, density and arrangement of the islands. In order to study the dependence of the structural properties of the islands and the quantum rings on growth conditions, atomic force microscope was used. Obtained results reveal that the size and the density of the In(Ga)As quantum rings strongly depend on the growth temperature, the annealing time and the thickness of the partial capping layer. From obtained results it is possible to conclude that to get round shape islands and high density one has to use growth temperature of 500 ̊C. In the case of formation of In(Ga)As quantum rings the effect of mobility anisotropy is observed that so the shape of the rings is not symmetric. To exclude this effect it is preferable to use a higher annealing temperature of 570 ̊C. Optical properties were characterized by PL spectroscopy. PL emission was observed from buried InAs quantum dots and In(Ga)As quantum rings grown with different annealing time and temperature and covered with a various thickness of the partial capping layer.
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Pro gradu -työn taustalla oli selvittää sähkökemiallisella polymeroinnilla tuotetun viologeenikalvon anioniselektiivisyyttä. Polymerointi toteutettiin sekä staattisella kennosysteemillä että suihkuvirtauskennolla (engl. wall-jet) käyttäen 1,3,5-tris-(N-metyyli-4-syanopyridinium)-2,4,6-trimetyylitribromidi-, trans-1,2-bis-(karbamoyyli-para-metyylisyano-pyridinium)-sykloheksaanidibromidi- ja 1,3-bis-[4-(para-metyylisyanopyridinium)-fenyyli-tioureido]-ksyleenidibromidilähtöaineita. Platina- ja kultasubstraateille muodostettuja viologeenikalvoja tutkittiin voltammetrisesti (CV), kronoamperometrisesti (CA), konduktometrisesta (GA) sekä kvartsikidemikrovaakaa (QCMB) apuna käyttäen. Tulosten perusteella polymeerirakenteet omasivat anionikaviteetteja mutta affiniteetit eri anionien väillä eivät korreloineet täydellisesti sähkökemiallisessa generoinnissa käytettyjen muotti-ionien kanssa. Selektiivisyyteen todennäköisesti vaikuttivat myös liuosfaasissa olleiden ionisten molekyylien ja solvatoituneiden anionien poolisuus ja hydraattiverhon koko. Lisäksi polymeroitujen viologeenien anionivakansseista suurin osa todettiin inaktiivisiksi. Kirjallisuuskatsauksen perusteella substituoidut γ,γ’-bipyridyylit ovat materiaaleina lupaavia ja yleisen sensoriteknologian mielenkiinnon kohteena mm. aurinkokennoissa, biosensoreissa ja elektronin delokalisaatioon perustuvissa värinäytöissä (ECD). Ongelmina löydetyissä sovellutuksissa ovat olleet bipyridyylien vuotaminen liuokseen, katalyyttisesti verraten hitaat elektroninsiirtoreaktiot ja yhdisteiden myrkyllisyys. Vastaavasti etuja ovat olleet polymeerien intensiiviset värit, väriskaalan muokattavuus, sähkökemiallisesti tuotetun radikaalikationin stabiilius vesiliuoksessa, katalyyttinen aktiivisuus ja helppo synteesireitti syanopyridiinilähtöaineista.
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Soitinnus: lauluääni, piano.
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The aim of this thesis was to study the health, the hospitalisations, and the use of communal health care services in very preterm children during the first five years of life. In addition, the effect of very preterm birth and prematurity-related morbidities on the costs of hospitalisations, other health care services and the cost per quality adjusted life years (QALY) were studied. This population-based study included all very preterm children (gestational age (GA) <32 weeks or birth weight<1501g, N=2 064) and full-term controls (GA 37+0−41+6, N=200 609) born in Finland during 2000-2003. The data sources included national register data, costing data from the participating hospitals and parental questionnaires. This study showed that most very preterm infants born in Finland survived without prematurity-related morbidities diagnosed during the first years of life. They required relatively little hospital care after the initial discharge, which accounted for the vast majority of the total four-year hospitalisation costs. However, a minority of children born very preterm later developing morbidities had a long initial length of stay and more re-admissions and outpatient visits during the five-year follow-up period. In particular, the number and costs of non-emergency outpatient visits were considerable in individuals with prematurity-related morbidities. The need and costs of hospitalisations decreased clearly with each follow-up year, even in individuals with morbidities. The health-care related costs during the fifth year of life in children born very preterm without prematurity-related morbidities were close to the costs in infants born healthy at term. The cost per QALY of 19,245 € was at an acceptable level already by four years of age in the very preterm population as a whole. Prematurity-related later morbidities and decreasing GA increased the costs per QALY. As the initial hospital stay accounted for a great majority of the total four-year costs, and the costs of hospitalisation decreased with each follow-up year, the cost per QALY is likely to decrease with age. In conclusion, the majority of costs arising after the initial hospitalisation were associated with morbidities related to prematurity. Therefore offering high-quality neonatal care to prevent later morbidities in very preterm survivors has a long-term impact on the cost per QALY. In addition, this study indicates that when estimating the costs of prematurity after the first year of life, one should calculate not only the hospitalisation costs, but also other costs for social welfare services, primary care, and therapies, as these exceed the hospitalisation costs in very preterm infants during the fifth year of life.