published_or_final_version / Urban Planning / Master / Master of Science in Urban Planning

Transmissible spongiform encephalopathies (TSEs), also known as prion diseases, are lethal and infectious neurodegenerative diseases of humans and animals. The misfolding of the normal, or cellular isoform of the prion protein (PrPC) into the abnormal disease-associated isoform of PrP (PrPSc) could change the properties of PrP, consequently, PrPSc has lethal infectivity to transmit diseases. The proteinaceous infectious particle consisting mainly of PrPSc is called prion. Transmissibility of prions is strongly influenced by multiple factors including PrP polymorphisms, species barriers (PrP sequence specificity) and prion strains (conformational specificity) by unknown mechanisms. Even though the ability of prions to cross a species barrier has been recognized, the precise mechanisms of interspecies prion transmission remain unclear. This dissertation research was conducted in order to learn more about the molecular mechanisms of conversion, propagation and transmission of PrPSc; about determinants of genetic susceptibility to infection in prion diseases; and about understanding those mechanisms, which might govern the zoonotic potential of prion diseases. First, we investigated the transmissibility risk of multiple strains of Chronic Wasting Disease, which is a cervid TSE, with humanized transgenic mice and showed that the transmission barriers between cervid and the humanized mice are high. Next, the structural factors underlying the species barrier of prion diseases were studied using cell culture systems by systematically introducing amino acid substitutions in the regions of PrP, where the most divergences of different PrP species are recognized. Thirdly, we investigated the effects of the genetic susceptibility to prions as well as conversion kinetics and properties of PrPSc using Tg mice expressing ovine PrP polymorphism (OvPrP) at codon 136 either alanine (A) or valine (V). The templating characteristics of OvPrPSc-V136 were dominant over OvPrPSc-A136 under co-expressions of OvPrPC-A136 and OvPrPC-V136. Finally, the function of PrP was studied in relation to the pathogenesis of Alzheimer’s disease. These studies demonstrated that the conformational compatibility between PrPC and PrPSc contributed to the conversion kinetics and species barrier. We concluded that the conformational compatibility of PrPC to PrPSc is controlled not only by the PrP sequence specificity but also by the tertiary structure of PrPC.

<p>The papermaking industry uses a large amount of starch each year, both as a wet-end additive and as a rheological modifier in surface sizing and coating colors. It is important to be able to reduce the amount of chemicals used in the papermaking and surface treatment process, to reduce costs and to make the process even more efficient. Interest in new high-performance starches is great. By using these new types of starches, improved recycling of barrier products may be obtained as well as a reduction in the use of synthetic sizing agents. The objectives of this work were to understand the behavior of temperature-responsive hydrophobically modified starches, where the solubility in water simply can be adjusted by temperature or by polymer charge, to improve the barrier properties, like the water vapor permeability, mechanical properties and water resistance (Cobb and contact angle) of papers surface sized by starch-containing solutions, and to investigate the potential for industrial use of these temperature-responsive starches. It was demonstrated that the temperature-responsive starches phase separate upon cooling and, depending on the charge density of the starch, a particulate precipitation or a gel-like structure was obtained. The starch with zero net charge showed a larger increase in turbidity than the starch with a cationic net charge, indicating that particulate precipitation is favored by a zero net charge and that the formation of a gel network is favored by charged starch molecules. Further, the starches formed inclusion complexes with surfactants, giving stabilization to the starches in the presence of surfactants. The net charge density of the starch and the charge of the surfactant determined whether or not an inclusion complex would form between them. Important mechanisms for the stability of the starch seemed to be formation of mixed micellar-like structures between the hydrophobic chain of the starch and the surfactant along the starch backbone in addition to formation of inclusion complexes between the starch and the surfactant. The hydrophobically modified starches showed higher hydrophobic surface character when applied to the paper surface above the critical phase separation temperature than with application at room temperature. Free films of the temperature-responsive starches showed good barrier against oxygen, but no barrier against water vapor. The mechanical properties decreased with addition of glycerol to the films.</p>

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Dielectric Barrier Discharge (DBD) excimer lamp is a very attractive source for Ultraviolet (UV) radiation. It has a number of advantages compared to the mercury lamp which is the main lamp used in the industry for UV production. Some of these advantages are instant UV radiation (no warm-up period), narrow UV spectrum, longer life times and simple construction. The DBD UV lamp can be used in number of applications like water disinfection, Plasma Display Panels (PDP) and surface treatment in the semiconductor industry. Yet, the full industrial application of this lamp still faces some problems mainly related to finding the optimum electrical driver to maximize the efficiency of such a lamp. This includes the type of the electrical waveform to generate and the power electronic driver to produce it. In this thesis, firstly a physically based circuit model for the DBD lamp using the Finite Volume Method (FVM) is developed. This model provides the electrical and optical characteristics of the lamp. Using this model the sensitivity of the lamp efficiency to the proposed electrical waveform has been determined. Secondly, the order of this FVM model has been reduced to obtain a model which is used in the design procedure of the proposed driver. Since the DBD lamp has a capacitive nature, a current controlled driver is proposed in this thesis as opposed to most of the published drivers which are voltage controlled drivers. The design of this driver is intended to enhance the electrical to optical efficiency of the lamp and therefore enhancing the overall efficiency of the system. The driver topology permits direct control of the peak lamp current and the operating frequency of the supplied current to the DBD lamp. The width of the current pulses is determined by the transformer magnetizing inductance and the lamp capacitance. Experimental results of the proposed driver connected to a XeCl DBD lamp are presented to validate the performance of the driver and to prove the concept of such a current controlled driver. The proposed driver performance is compared to a voltage source driver which was also implemented. The proposed driver produced higher overall system efficiency but at the expense of a reduction in the driver efficiency as compared to the voltage source driver. The complete system, which consists of the developed FVM based model and the equivalent circuit of the proposed driver, was simulated and the results were compared to the experimental results to validate the accuracy of the developed model for the DBD lamp.

Cronobacter species cause serious infections such as meningitis and enteritis in newborns and neonates, with the major vehicle being contaminated powdered infant formula. The main objectives of this study were i) to identify potential virulence factors, such as enterotoxin production; ii) characterize the gene(s) involved in adhesion and invasion of the human brain microvascular endothelial cells (HBMEC); and iii) determine whether strains from clinical, food, and environmental sources differ in their ability to produce surface-attached bacterial aggregates, known as biofilms. Random transposon mutagenesis was used on strains demonstrating the best adherence and invasion to blood- brain barrier cell lines (BBB). Isogenic mutants were then screened for increased or decreased adherence and invasion. Screening of the transposon library identified one isogenic mutant of a clinical strain which lost the ability to adhere to BBB cells. The transposon rescue revealed the insertion site to be within a diguanylate cyclase (DGC) gene. The major function of DGC in many Gram-negative bacteria is to synthesize cyclic diguanylate (c-di-GMP), a secondary bacterial metabolite known for regulating biofilm formation, motility, and virulence or aspects of microbial pathogenicity. Based on the findings of this study, DGC appears to play an important role in Cronobacter species’ ability to produce biofilms and may also have a role of the pathogenicity in the microorganism.

Capacity to perform prolonged exercise is reduced in high ambient temperatures, but this premature fatigue is not adequately explained by peripheral mechanisms. The aim of this thesis was to examine some possible underlying mechanisms of central fatigue operating during prolonged exercise in a warm environment. The first series of experiments investigated the effect of nutritional manipulation of central serotonergic activity through alterations to the plasma concentration ratio of free-tryptophan to branched-chain amino acids (f-TRP:BCAA). In contrast to previous reports, acute BCAA supplementation failed to alter perceived exertion and delay the onset of fatigue (Chapter 3). This response was similar when exercise was preceded by an exercise and diet regimen designed to reduce glycogen availability (Chapter 4). The ingestion of meals containing added carbohydrate and fat did not alter f-TRP:BCAA at rest (Chapter 5). Acute dopaminergic / noradrenergic reuptake inhibition with bupropion increased exercise perfonnance by 9 % in warm conditions (30C), but this effect was not apparent at 18C (Chapter 6). This response was accompanied by attainment of a higher core temperature and heart rate towards the end of the bupropion trial in the heat despite no detectable difference in perceived exertion and thermal stress. These data suggested that maintenance of catecholaminergic activity may dampen inhibitory signals from the CNS due to the attainment of a high core temperature, allowing power output to be maintained. The blood-brain barrier (BBB) regulates the exchange of substances between the cerebral interstitial fluid and the blood to maintain a stable environment for the CNS. If the BBB is compromised this may adversely influence nonnal brain function. Serum S1OOb, a proposed peripheral marker of BBB penneability, was increased following exercise in a warm environment (Chapter 7). These data indicate that exposure to combined exercise and heat stress may result in a loss of BBB integrity.

Contingent claims models have recently been applied to the field of corporate insolvency prediction in an attempt to provide the art with a theoretical methodology that has been lacking in the past. Limited studies have been carried out in order to empirically compare the performance of these “market” models with that of their accounting number-based counterparts. This thesis contributes to the literature in several ways: The thesis traces the evolution of the art of corporate insolvency prediction from its inception through to the present day, combining key developments and methodologies into a single document of reference. I use receiver operating characteristic curves and tests of economic value to assess the efficacy of sixteen models, carefully selected to represent key moments in the evolution of the art, and tested upon, for the first time, post-IFRS UK data. The variability of model efficacy is also measured for the first time, using Monte Carlo simulation upon 10,000 randomly generated training and validation samples from a dataset consisting of over 12,000 firmyear observations. The results provide insights into the distribution of model accuracy as a result of sample selection, which is something which has not appeared in the literature prior to this study. I find overall that the efficacy of the models is generally less than that reported in the prior literature; but that the theoretically driven, market-based models outperform models which use accounting numbers; the latter showing a relatively larger efficacy distribution. Furthermore, I obtain the counter-intuitive finding that predictions based on a single ratio can be as efficient as those which are based on models which are far more complicated – in terms of variable variety and mathematical construction. Finally, I develop and test a naïve version of the down-and-out-call barrier option model for insolvency prediction and find that, despite its simple formulation, it performs favourably compared alongside other market-based models.

Globaliseringen ökar och med de tillhörande samhällsförändringarna utsätts hälso- och sjukvården för kommunikationsproblem i form av språkbarriärer. Dessa barriärer påverkar sjuksköterskans möjlighet att utföra god omvårdnad samt förutsättningen att bygga en relation till patienten. Inte minst påverkas patientsäkerheten då viktig information inte kan förmedlas. Syftet var att undersöka sjuksköterskans upplevelse av språkbarriärer vid omvårdnad av patienter som inte talar landets officiella språk. Elva vetenskapliga artiklar användes i denna litteraturstudie. Sjuksköterskorna beskrev sig uppleva språkbarriärer som ett vanligt och frustrerande problem som ökade sjuksköterskans stress och arbetsbelastning. Den auktoriserade tolken beskrevs som svårtillgänglig men även som en trygghet för sjuksköterskan i omvårdnaden av patienter som inte förstod språket. Ett etiskt dilemma som framkom var hur patienters barn istället användes som tolk i situationer då auktoriserad tolk ej fanns tillgänglig. I framtida forskning är det aktuellt att studera effekterna av språkbarriärer på patientsäkerheten då detta upplevts som ett genomgående problem av sjuksköterskorna. / The globalisation is increasing, with its demographic changes the healthcare is exposed to communication problems in the form of language barriers. These barriers affect the nurse’s ability to perform proper care and their conditions for building relations with the patient. Not least is the security of the patients affected when important information cannot be transferred. The aim of this literary review was to study the nurse’s experience of language barriers while caring for patients who do not speak the official language of the country. Eleven scientific articles where used in this literary review. The nurses explained that they experienced language barriers as a common and frustrating problem which increased the nurses’ stress and workload. The authorized interpreter was described as unavailable but also as a security for the nurses when caring for patients who do not understand the language. An ethical dilemma that occurred was how the children of patients where used as interpreters instead of authorized interpreters. For future research, it is suitable to study the effects of language barriers on patient security as this is a reoccurring problem according to the nurses.

Bakgrund: Invandring till Sverige ökar. Enligt hälso- och sjukvårdslagen har alla rätt till lika sjukvård. Patienter har rätt till information och självbestämmande. För att uppnå delaktighet krävs att sjuksköterska och patient kan kommunicera. Det är därför av stort värde att beskriva förutsättningar i vården för patienter som har otillräckliga eller inga kunskaper i svenska. Syfte: Att undersöka förutsättningarna för en patient, som har otillräckliga eller inga kunskaper i svenska, att få god somatisk slutenvård samt att undersöka hur kommunikation mellan patient och sjuksköterska kan underlättas. Metod: En kvalitativ studie baserad på semistrukturerade intervjuer där åtta sjuksköterskor från ett universitetssjukhus i Sverige har intervjuats. Intervjuerna blev inspelade, transkriberade och analyserade med kvalitativ innehållsanalys. Resultat: Sjuksköterskan får ofta hitta egna lösningar och verktyg. Ett av de mest använda verktygen är det digitala verktyget Google Translate. Tolk används sällan även om sjuksköterskorna gärna ser att det används mer. Att inte kunna förstå personalen och inte ha möjlighet att kommunicera effektivt leder till att patienten förlorar mycket av sitt sociala liv, informationen blir bristfällig och delaktigheten blir lidande. Detta kan eventuellt leda till att patientens säkerhet påverkas. Slutsats: Språkbarriären påverkar patientens sociala behov, delaktigheten och informationsflödet. Mer användning av tolk efterfrågas men är omständligt. Digitala verktyg är ibland det enda alternativet, dessa verktyg är dock varken medicinskt anpassade eller säkra att översätta med. / Background: Immigration to Sweden is increasing. According to the Swedish Health Care Act, everyone is entitled to equal health care. Patients have the right to information and self-determination. To achieve participation requires that the nurse and patient can communicate. It is therefore of great value to describe the conditions of the care of patients who have inadequate or no knowledge of Swedish. Aim: To investigate conditions for a patient, who have inadequate or no knowledge of Swedish, to receive good somatic inpatient care and how communication between patient and nurse can be facilitated. Method: A qualitative study based on semi-structured interviews where eight nurses from a Swedish university hospital was interviewed. The interviews were recorded, transcribed and analyzed using qualitative content analysis. Result: Nurses often find their own solutions and tools. One of the most used tools is the digital tool Google Translate. Interpreters are rarely used even if the nurses would like to see the interpreter and telephone interpreting being used more. Not being able to understand the staff and not having the ability to communicate in a good way causes the patient to lose much of their social life, insufficient information and lack of participation, this may have an impact on the patient safety. Conclusion: The language barrier affects the patient's social needs, participation and the information flow. More use of interpreters is requested but is cumbersome. Digital tools are sometimes the only option, however, these tools are neither medically customized nor secure to translate with.