The Accidental President of Brazil: An Interview with Fernando Henrique Cardoso

Latin American Studie

The Influence of Regional Differences of Native German Speakers on the L2 English Pronunciation of Selected Phonetic Features

Pronunciation, as an aspect of non-native accent, is one of the most noticeable aspects of English as a Foreign Language. Age of learning may have an impact on whether nativelike pronunciation can be attained. Furthermore, standard as well as regional dialects may have an influence on pronunciation through cross-linguistic influence. This project aims to gain a better understanding of possible regional variations in native German speakers’ English pronunciation by examining the production of specific consonants. The project is framed by the discussion of English as a Second Language compared to English as an International Language and whether learners’ wishes should be considered. The analyses undertaken in this project are based on 26 individually structured interviews, which included a production task of 14 sentences each containing a specific consonant sound. No significant difference between German regions was discovered, which may largely be due to the low number of participants and a selection bias discovered during the project

EXPLORING CHARACTERISTICS OF VACCINATED DOGS THAT FAIL TO ACHIEVE AN ADEQUATE LEVEL OF RABIES VIRUS NEUTRALIZING ANTIBODIES

Master of Public HealthPublic Health Interdepartmental ProgramMajor Professor Not ListedThis study provides additional findings that could potentially have implications for current and future guidelines as they pertain to pet travel, vaccination campaigns, and exposure recommendations. Furthermore, the study provides insight into additional research needed within the area of rabies serology specifically as it pertains to the influence of breed or dog size, primary versus anamnestic responses to vaccination, and smaller sampling intervals to determine the initial detection of immunocompetence

[18F]Fluoroform - a versatile building block for PET tracer synthesis

Fluorine-18 (half-life: 110 min) is a popular radionuclide for positron emission tomography (PET), a functional imaging technique that non-invasively visualizes biochemical processes in vivo. It can be introduced into tracer molecules via fluorine-18 labelled building blocks. [18F]Fluoroform is a building block that has received much interest in recent years and is used to introduce radioactive CF3 groups into the tracer molecules. However, shortcomings of [18F]fluoroform, such as the low molar activities typically obtained and the limited 18F-trifluoromethylation strategies available, hampered its use in PET tracer synthesis so far. The aim of this thesis was therefore to address these shortcomings and develop [18F]fluoroform into a useful building block for PET tracer synthesis. In Chapter 1 a general introduction into the topic is provided, discussing the basic concepts of positron emission tomography, different radionuclides and radiofluorination strategies. Furthermore, the building block [18F]fluoroform is introduced. Chapter 2 gives a comprehensive overview of the fluorine-18 labelled building blocks used in PET tracer synthesis from 2010-2016. The overview comprises aromatic and aliphatic building blocks, including [18F]fluoroform. Chapter 3 reports the development of a new method to obtain reactive [18F]fluoride omitting the commonly used azeotropic drying procedures. For this method, hydrated [18F]fluoride was reacted with a bistriflate precursor to form gaseous [18F]triflyl fluoride. The [18F]triflyl fluoride was distilled into a dry organic solvent containing base and cryptand, where it was converted to free [18F]fluoride. Besides being fast, reliable, and high-yielding, this novel method offers high flexibility in the subsequent radiofluorination reaction, particularly enabling the reduction of base and cryptand amounts. Chapter 4 describes the optimization of the [18F]fluoroform synthesis towards a high molar activity procedure. Stability studies with the labelling precursor difluoroiodomethane showed that difluoroiodomethane was unstable under the basic radiofluorination conditions, probably causing the low molar activity typically observed with [18F]fluoroform. By reducing the amount of base and cryptand 100-fold compared to standard radiofluorination conditions the stability of difluoroiodomethane and the molar activity of [18F]fluoroform could be drastically improved. Radiochemical yields of around 40% and molar activities close to 100 GBq/µmol were obtained. The optimized synthesis procedure was automated on a commercially available synthesizer to enhance applicability and facilitate the use in other PET centres. In chapter 5 a novel precursor for the synthesis of [18F]fluoroform is presented, 1-(difluoromethyl)-3-methyl-4-phenyl-1H-1,2,3-triazol-3-ium triflate. It was investigated whether this precursor could provide [18F]fluoroform with even higher molar activities than difluoroiodomethane. It was found that also for this precursor reduction of base and cryptand amounts led to increased precursor stability and high molar activities of [18F]fluoroform. Especially in the automated synthesis the triazolium precursor provided [18F]fluoroform with some of the highest molar activities observed so far (~150 GBq/µmol). Chapter 6 reports the first synthesis and application of fluorine-18 labelled Ruppert-Prakash reagent ([18F]Me3SiCF3) as 18F-trifluoromethylation agent. [18F]Me3SiCF3 was synthesized by reaction of [18F]fluoroform with trimethylsilyl chloride and obtained with radiochemical yields of 85-95% and radiochemical purities of >95%. It was reacted in a simple model reaction with a range of aromatic aldehydes and ketones and proved good reactivity as well as a complementary substrate scope to previously reported methods. Chapter 7 describes the development and evaluation of the new tracer [18F]cinacalcet for the localization of overactive parathyroid glands for surgery. [18F]Cinacalcet was synthesized using the optimized [18F]fluoroform procedure described in chapter 4, followed by aromatic 18F-trifluoromethylation of a boronic acid precursor. [18F]Cinacalcet was obtained with an overall radiochemical yield of 8±4% and a molar activity of 40±11 GBq/µmol within 1 hour (n=7,dc). A biodistribution and metabolite study was performed in healthy rats, showing decent uptake in the parathyroid glands and fast blood metabolism. Chapter 8 gives a short summary and outlook

Influence of surgery and dexamethasone on cell-mediated immune responses in patients with meningiomas.

Cell-mediated cytotoxicity (CTX) was studied in meningioma patients before and within 2 weeks of complete excision of the tumour, using the [3H]-prolin- microcytotoxicity test. Three of 7 patients tested before surgery showed specific CTX, 2 revealed a "non-specific" (tumour-unrelated) response, and 2 were non-reactive. After surgery, CTX decreased from 84 to 50% in one patient and became negative in 2 others previously positive. One of 2 patients showing "non-specific" CTX preoperatively became positive, while the other remained unchanged. All patients were receiving dexamethasone (DXM) at the time they were tested. Lymphocyte responses to PHA were not significantly different before or after surgery (i.e. after prolonged treatment with DXM), from healthy controls. Blocking activity could be detected in the sera of all 3 patients before surgery. This activity was not specific for meningiomas. Paradoxically, the same sera did not inhibit the proliferative response to PHA. Serum from only one patient consistently suppressed the blastogenic response of homologous lymphocytes to PHA. Inhibitory activity was associated with the IgG fraction of his serum

A Supersymmetry Model of Leptons

If supersymmetry (SUSY) is not for stabilizing the electroweak energy scale, what is it used for in particle physics? We propose that it is for flavor problems. A cyclic family symmetry is introduced. Under the family symmetry, only the $\tau$-lepton is massive due to the vacuum expectation value (VEV) of the Higgs field. This symmetry is broken by a sneutrino VEV which results in the muon mass. The comparatively large sneutrino VEV does not result in a large neutrino mass due to requiring heavy gauginos. SUSY breaks at a high scale $\sim 10^{13}$ GeV. The electroweak energy scale is unnaturally small. No additional global symmetry, like the R-parity, is imposed. Other aspects of the model are discussed.Comment: 10 pages, no figure, revtex