The International Temperature Scale of 1990 (ITS-90) defines the present S.I.(“System International”) means of measuring temperature. The ITS-90 uses the freezing points of metals to define temperature fixed points. It also uses long-stemplatinum resistance thermometers to interpolate between the fixed points from 660 °Cdown to 84 K (if one includes the Argon triple point). Impurities are a major source of uncertainty in the fixed point temperature (of the order of 1 mK). And a better understanding of the impurity effect is required to improve top-level metrologicalthermometry. Most historical experiments with impurities have worked at a muchhigher levels of impurities – say of the order of 100ppm - and in arrangements that are not used on a day-to-day basis in a metrology laboratory. This thesis describes the deliberate doping of tin and aluminium, each with three different impurities and the effects of these on the temperature of the tin and aluminium liquid-solid phase transitions. The impurities, of the order of 1-30 ppm,were Co, Pb and Sb in the tin and Cu, Si and Ti in the aluminium. The tin and aluminium samples were in the form of ~0.3 kg ingots that would normally be used to realise an ITS-90 fixed point. Measurements were made using equipment normally available in a metrological thermometry laboratory, rather than using specially prepared samples. The samples were chemically analysed (by Glow Discharge Mass Spectrometry(GD-MS)) before and after the doping. Using the amount of dopants introduced,and/or the chemical analysis data, the measured temperature changes were compared with those interpolated from the standard text. The experimental undoped liquid-solid transition curves were also compared against theoretical curves (calculated from atheoretical model MTDATA). The results obtained did not disagree with the Hansen interpolated values (though there was considerable uncertainty in some of the measurements (e.g. a factor of 2 ormore) due to the measurement of small changes. Within these uncertainties it indicatesthat the Sum of Individual Estimates (SIE) method of correcting for, at least, metal impurities in otherwise high purity metals remain valid. However the results also showed considerable discrepancies between the initial measured and calculated temperature shifts (based on the pre-existing impurities prior to doping) suggesting that there may be impurities that are not (separately) detected by the GD-MS method. There was evidence that the thermal history of the metal phase transitions can cause considerable segregation of some impurities, particularly those likely to increase the phase transition temperature through a peritectic (“positive” impurities), and that the effects of this segregation can be clearly seen on the shape of the melting curves of thetin doped with Sb. Some of the aluminium doped with Ti freezing curves may also show evidence of a“concave up” shape at the start of the freezing curve, as previously calculated by MTDATA, though the effect is not as pronounced. All individual phase transition measurements - made over tens of hours – were repeated at least three times and found to be reproducible, hence providing a real dataset that can be used for comparison with theoretical models still under development.

During gas turbine development testing, measurements of the gas-path stagnation temperature are used to characterise the engine running condition and establish individual engine component performance. These measurements are typically acquired using passively ventilated thermocouple probes, which are capable of achieving absolute stagnation temperature uncertainties of approximately 0.5 %. Historically, this measurement accuracy has been considered adequate to evaluate gains in turbomachinery efficiency. However, realisable turbomachinery efficiency gains have recently become sufficiently small that an improvement in measurement accuracy is now required. This has resulted in the specification of a target absolute stagnation temperature uncertainty of 0.1 %. The research presented in this thesis focusses on the development of a new stagnation temperature probe that will achieve a measurement uncertainty close to the target value. The new probe has been designed to utilise a thin-film platinum resistance thermometer (PRT) as the temperature sensitive element. For certain aspects of gas turbine engine testing, this type of sensor offers an improvement in measurement accuracy compared to a thermocouple.

Abstract Ovarian cancer is the fifth leading cause of cancer-associated death in women in Finland. Although ovarian cancer is relatively common, the precise mechanism of its development is still unknown. Additionally, it appears that the modes of pathogenesis differ depending on histotype. Although the initial response to platinum-based chemotherapy is usually good, the majority of ovarian cancer patients relapse and develop platinum resistance. This is a major problem in the treatment of ovarian cancer. Reactive oxygen species (ROS) are metabolites of oxygen. They are continuously formed in normal cells as a by-product of aerobic respiration and they play an important role in normal cell functions. Oxidative stress occurs when ROS formation overrides the antioxidative defence system. Oxidative stress is associated with carcinogenesis. A small proportion of cancer cells are stem cells that survive initial chemotherapy. These cells are suspected of being associated with the development of platinum resistance. To evaluate the significance of oxidative stress in ovarian cancer we examined ROS-derived damage and antioxidant regulators in benign and borderline ovarian tumours and ovarian cancer samples by immunohistochemistry and analysis of serum samples. The existence of cancer stem cell markers was also assessed in ovarian cancer samples. The expression levels of various markers were compared with clinicopathological parameters. Our results confirm that oxidative stress (8-hydroxydeoxyguanosine) exists in benign tumours and antioxidant enzymes, such as peroxiredoxins and thioredoxin are widely expressed in benign and borderline tumours. Oxidative stress was associated with poor survival, higher stage and platinum resistance in ovarian cancer. Oxidative stress markers were more strongly expressed in certain histotypes of ovarian cancer, such as serous and endometrioid type. Cancer stem cell markers were found in ovarian cancer and they were associated with the development of platinum resistance. These observations are beneficial in understanding the pathobiology of ovarian cancer and help in the design of new treatment options. / Tiivistelmä Munasarjasyöpä on yksi merkittävistä syöpäkuolleisuuden aiheuttajista naisilla Suomessa. Se on kohtalaisen yleinen, mutta sen perimmäinen syntymismekanismi on vielä epäselvä. Lisäksi näyttää siltä, että eri histologioilla syntymekanismit poikkeavat toisistaan. Vaikka yleensä platinapohjaisella solunsalpaajahoidolla saadaan hyvä vaste, suurimmalla osalla hoidetuista potilaista tauti uusii ja kehittyy vastustuskyky platinapohjaisille solunsalpaajille. Tämä on suuri ongelma munasarjasyövän hoidossa. Vapaat radikaalit ovat hapen johdannaisia. Niitä muodostuu jatkuvasti soluissa soluhengityksen sivutuotteena, ja niillä on tärkeä merkitys normaaleissa solun toiminnoissa. Jos vapaiden radikaalien tuotanto ylittää antioksidatiivisen puolustusjärjestelmän, syntyy oksidatiivinen stressitilanne. Oksidatiivisen stressin on todettu olevan yhteydessä useiden syöpien syntymiseen. Osaa syövän soluista kutsutaan kantasoluiksi. Nämä solut voivat selvitä solunsalpaajahoidoista ja niiden epäillään olevan yhteydessä vastustuskyvyn kehittymisessä platinapohjaisia sytostaatteja kohtaan. Tutkimuksessamme arvioimme oksidatiivisen stressin merkitystä munasarjakasvaimissa. Tutkimme vapaiden radikaalien aiheuttamia vaurioita ja antioksidatiivisia säätelijöitä hyvänlaatuisissa, rajalaatuisissa sekä munasarjasyöpä kasvaimissa immunohistokemiallisesti ja seeruminäytteistä. Lisäksi selvitimme syövän kantasolumerkkiaineiden esiintymistä munasarjasyövässä. Tutkittujen merkkiaineiden pitoisuuksia verrattiin kliinisiin potilastietoihin. Tutkimustuloksemme mukaan oksidatiivista stressiä (8-hydroxydeoxyguanosine) esiintyi jo hyvänlaatuisissa kasvaimissa. Myös antioksidatiiviset entsyymit, kuten peroksiredoksiinit ja tioredoksiini, esiintyivät jo hyvänlaatuisissa ja rajalaatuisissa kasvaimissa. Oksidatiivinen stressi oli yhteydessä huonompaan tautiennusteeseen ja platinakohtaisen vastustuskyvyn kehittymiseen. Oksidatiivista stressiä oli enemmän seroosissa ja endometrioidissa munasarjasyöpätyypissä. Syövän kantasolumerkkiaineita esiintyi munasarjasyövässä, ja ne olivat yhteydessä huonontuneeseen hoitovasteeseen platinapohjaisille solunsalpaajille. Tulokset auttavat ymmärtämään munasarjasyövän syntymekanismeja ja suunnittelemaan uusia hoitovaihtoehtoja erityyppisissä munasarjasyövissä.

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