Severe motor vehicle accidents (MVAs) represent one of the most often occurring psychological traumas, and are a leading cause of Posttraumatic Stress Disorder (PTSD). However, not all persons develop PTSD after traumatic events and a great proportion of patients who show symptoms initially recover over time. This has stimulated research of psychological and biological factors that explain development and maintenance of the disorder. Fortunately, this highly distressing condition can be effectively treated, e.g. via cognitive behavioral therapy (CBT). However, brain mechanisms underlying changes due to psychological therapy in PTSD are almost unknown (Roffman, Marci, Glick, Dougherty, & Rauch, 2005). On the other hand there are observations of positive changes following trauma called Posttraumatic Growth (PTG), which have stimulated research of associated psychological processes and factors. However, there is a lack of research about the relation of biological variables (e.g. measures of brain function) and PTG. Theories of brain asymmetry and emotion (Davidson, 1998b, 2004b; Heller, Koven, & Miller, 2003) propose that asymmetries of brain activation are related to certain features of human emotion (e.g. valence, approach or withdrawal tendencies, arousal). Whereas an enormous increase in the understanding of structural and functional abnormalities in PTSD could be achieved in the last decades due to neuroimaging research, there are still numerous unanswered questions. Especially, there is only little research explicitly examining activation asymmetries in PTSD. Furthermore, as mentioned, research is sparse investigating alterations of brain function that are associated with successful psychological treatment of PTSD. Finally, there is no published study examining how measures of brain function are related to PTG. This thesis presents 3 studies investigating electroencephalographic (EEG) asymmetries in survivors of severe motor vehicle accidents. The first part of the thesis (chapter 2) is devoted to a literature review about description (chapter 2.1), epidemiology (chapter 2.2 and 2.3), risk factors (chapter 2.4), psychological theories (chapter 2.5), biological mechanisms particularly neuroimaging findings (chapter 2.6), and treatment of PTSD (chapter 2.7.). Chapter 2.8 gives a short review on definition and research of Posttraumatic Growth. Chapter 2.9 provides an overview of models and research regarding brain asymmetry and emotion. In chapter 3.1, a study is presented that investigated hemispheric asymmetries (EEG alpha) among MVA survivors with PTSD, with subsyndromal PTSD, and without PTSD as well as non-exposed healthy controls during a baseline condition and in response to neutral, positive, negative, and trauma-related pictures (study I). Next, the findings of study II are presented (chapter 3.2). This study examined the effect of cognitive behavioral therapy on measures of EEG activity. Therefore, EEG activity before and after CBT in comparison to an assessment only Wait-list condition was measured. In chapter 3.3 a correlational study (study III) is presented that examined the relationship between frontal brain asymmetry and selfreported posttraumatic growth after severe MVAs. Finally, in chapter 4 the findings are summarized and discussed with respect to (1) the state/trait debate in frontal asymmetry research and (2) current psychological theories of PTSD and PTG. In addition, the use of neuroscientific research for psychotherapy is discussed. Suggestions are presented for future goals for “brain” research of PTSD and treatment of PTSD. / Schwere Verkehrsunfälle stellen eines der am häufigsten vorkommenden psychologischen Traumata dar, und sind eine Hauptursache der Posttraumatischen Belastungsstörung (PTBS). Jedoch entwickeln nicht alle Personen nach traumatischen Ereignissen eine PTBS und bei einem Großteil remittieren anfängliche PTBS-Symptome. Dies stimulierte die Erforschung von psychologischen und biologischen Faktoren, die die Entstehung und Aufrechterhaltung der PTBS erklären. Glücklicherweise kann die PTBS effektiv, z.B über die kognitive Verhaltenstherapie (KVT), behandelt werden. Jedoch sind Gehirnmechanismen, die mit klinischen Änderungen aufgrund der psychologischen Therapie in PTSD einhergehen, nahezu unbekannt (Roffman, Marci, Glick, Dougherty, Rauch, 2005). Auf der anderen Seite gibt es Berichte von positiven Änderungen nach traumatischen Ereignissen, die als Posttraumatische Reifung (PTR) bezeichent werden. Dies hat in kürzerer Vergangenheit die Forschung von verbundenen psychologischen Prozessen und Faktoren stimuliert. Jedoch gibt es kaum Untersuchungen über die Beziehung von biologischen Variablen (z.B Messungen der Gehirnfunktion) und PTR. Diese Arbeit präsentiert 3 Studien, die electroenzephalographische (EEG) Asymmetrien bei Opfern schwerer Verkehrsunfälle untersuchten. Der erste Teil der Arbeit (Kapitel 2) widmet sich einer Literaturrezension über: die Beschreibung (Kapitel 2.1), Epidemiologie (Kapitel 2.2 und 2.3), Risikofaktoren (Kapitel 2.4), psychologische Theorien (Kapitel 2.5), biologische Mechanismen besonders Neuroimaging Ergebnisse (Kapitel 2.6), und Behandlung der PTBS (Kapitel 2.7.). Kapitel 2.8 gibt einen kurzen Überblick über die Definition und Forschung zur Posttraumatischen Reifung. Kapitel 2.9 gibt eine Übersicht zu aktuellen Modellen und empirischen Befunden bezüglich Gehirnasymmetrien und Emotionen. Kapitel 3.1 präsentiert eine Studie, in der hemisphärische Asymmetrien (im EEG-Alpha Band) bei Unfallopfern mit PTBS, subsyndromaler PTBS, und ohne PTBS sowie gesunden Kontrollpersonen ohne Unfall untersucht wurden: während einer Ruhemessung und einer Emotionsinduktions-bedingung (neutrale, positive, negative und trauma-spezifische Bilder) (Studie I). Danach werden die Ergebnisse der Studie II (Kapitel 3.2) präsentiert. Hier wurde die Wirkung der kognitiven Verhaltenstherapie auf Messungen der EEG-Aktivität untersucht. Deshalb wurde EEG-Aktivität vor und nach einer KVT im Vergleich mit einer Warten-Gruppe gemessen. Kapitel 3.3 präsentiert eine Korellationsanalyse (Studie III), bei der die Beziehung zwischen der frontalen Gehirnasymmetrie und posttraumatischer Reifung untersucht wurde. Am Ende der Arbeit (Kapitel 4) werden die Ergebnisse zusammengefasst und in Bezug auf (1) die state/trait-Debatte im Rahmen der Asymmetrie-Forschung diskutiert sowie (2) ein Bezug zu aktuellen psychologische Theorien von PTSD und PTG hergestellt. Außerdem wird der Nutzen von neurobiologischer Forschung für die Psychotherapie besprochen. Dabei werden Vorschläge für zukünftige Projekte für die "Gehirn"-Forschung im Zusammenhang mit der PTBS, deren Behandlung und PTG gemacht.

The aim of the diploma thesis was the diagnostics of plasma generated in the atmosphere simulating conditions on Mars. This diploma thesis is focused on the simulation of Mars’ atmosphere at atmospheric pressure and normal laboratory temperature. Due to the similar conditions of Mars' atmosphere with Earth, this planet has been explored in the past as well as up to now. Mars' atmosphere is composed mostly of carbon dioxide, which makes up more than 90 % of Mars' atmosphere. A glow discharge generated in a special reactor at atmospheric pressure at a flow of pure CO2 was used to simulate the atmosphere of Mars. Part of the measurement was performed only in pure CO2 with changing current of 20, 25, 30, 35 and 40 mA. Part of the measurements was focused on the study of the effect of the addition of various gases, such as nitrogen, hydrogen and methane, at changes in their flow rates of 1, 2, 3, 4 and 5 sccm. The products formed in the special reactor were analysed using a mass spectrometer with proton ionization and with a flight time analyser. Optical emission spectrometry was used for plasma diagnostics and composition. Mainly simple aliphatic hydrocarbons, alcohols, aldehydes, and ketones were detected. With increasing flow rates of the individual gases, more complex aromatic compounds with higher molecular weights were formed. Corresponding mass and optical emission spectra were measured simultaneously.

Functionally graded materials (FGMs) are inhomogeneous materials in which the material properties vary with respect to space. Research has been done by scientific community in developing techniques like photothermal radiometry (PTR) to measure the thermal conductivity and volumetric heat capacity of FGMs. One of the problems involved in the technique is to solve the inverse problem, i.e., estimating the thermal properties after the frequency scan has been obtained. The present work involves finding the unknown thermal conductivity and volumetric heat capacity of the FGMs by using finite volume method. By taking the flux entering the sample as periodic and solving the discretized 1-D thermal wave field equation at a frequency domain, one can obtain the complex temperatures at the surface of the sample for each frequency. These complex temperatures when solved for a range of frequencies gives the phase vs frequency scan which can then be compared to original frequency scan obtained from the PTR experiment by using a residual function. Brute force and gradient descent optimization methods have been implemented to estimate the unknown thermal conductivity and volumetric specific heat of the FGMs through minimization of the residual function. In general, the spatial composition profile of the FGMs can be approximated by using a smooth curve. Three functional forms namely Arctangent curve, Hermite curve, and Bezier curve are used in approximating the thermal conductivity and volumetric heat capacity distributions in the FGMs. The use of Hermite and Bezier curves gives the flexibility to control the slope of the curve i.e. the thermal property distribution along the thickness of the sample. Two-layered samples with constant thermal properties and three layered samples in which one of the layer has varying thermal properties with respect to thickness are considered. The program is written in Fortran and several test runs are performed. Results obtained are close to the original thermal property values with some deviation based on the stopping criteria used in the gradient descent algorithm. Calculating the gradients at each iteration takes considerable amount of time and if these gradient values are already available, the problem can be solved at a faster rate. One of the methods is extending automatic differentiation to complex numbers and calculating the gradient values ahead; this is left for future work.

Les matériaux polymères sont aujourd'hui très présents dans notre environnement et deviennent irremplaçables pour de nombreuses applications : emballage, textile, mobilier,... La connaissance du cycle de vie de ces matériaux, de la production à leur destruction, devient importante pour nos sociétés. Par exemple ces matériaux peuvent émettre des Composés Organiques Volatils qui sont souvent toxiques et leur impact sur le milieu doit être évalué. L’objectif de ce travail de thèse a été de développer une méthode au laboratoire pour identifier et quantifier ces émissions. La difficulté provient de la grande diversité des composés qui peuvent être émis. Par ailleurs la méthode nécessite une fréquence de mesure élevée (temps réel) souvent incompatible avec les techniques actuelles. Une solution analytique couplant un four et un spectromètre de masse haute résolution associé à une méthode d’ionisation chimique contrôlée a été développée. Celle-ci est basée sur un spectromètre FT-ICR compact à bas champ magnétique : BTrap. Les points forts de cette technique sont la très haute résolution en masse qui permet de mesurer la masse exacte des composés et la détection multi composés, simultanée sur toute la gamme de masse. L’ionisation chimique contrôlée permet l'ionisation douce et quantitative des molécules d’intérêt. Le transfert de proton à partir de l’ion H₃O⁺ (PTRMS) a montré son potentiel pour la détection des COV dans de nombreux domaines. Après une présentation du contexte et du besoin, le dispositif expérimental développé est détaillé. La validation de celui-ci pour l'analyse de gaz traces a été effectuée au LPGP, sur un système de dépollution par plasma froid. Les résultats de dégradation de l'acétaldéhyde en fonction des conditions de fonctionnement du réacteur sont présentés.L’ionisation par PTR conduit habituellement à la molécule protonée ce qui simplifie l’identification. Cependant des fragmentations peuvent être observées. L’utilisation d’un précurseur d’ionisation chimique plus lourd et moins réactif que H₃O⁺ pourrait minimiser ces phénomènes. L’utilisation du diflurobenzène protoné a été testée et comparée à celle de l’ion H₃O⁺. Pour cela, des études cinétiques ont été menées sur une série d’alcools connus pour fragmenter avec H₃O⁺, et confirment l'intérêt du nouveau précurseur.Le poly(méthacrylate de méthyle) (PMMA) est un matériau très répandu : plexiglass. Sa dégradation est a priori relativement simple puisqu’il s’agit très majoritairement d’une dépolymérisation, accompagnée de la formation de produits minoritaires. En conséquence, son étude nous a paru intéressante pour la mise au point et la validation de la méthode. La dégradation du PMMA a été étudiée sous atmosphère inerte, puis oxydante. Les résultats obtenus sont présentés : produits émis, bilan en masse, et apport du suivi en temps réel de la dégradation, montrant en particulier que les produits minoritaires sont émis après le monomère.Enfin une dernière partie de conclusion présente les perspectives pour cette nouvelle méthode. / Polymeric materials are now ubiquitous in our environment and become irreplaceable for many applications such as packaging, textile or furniture. Knowledge of the life cycle of these materials from production to destruction becomes important for our societies. For instance, plastics may release Volatile Organic Compounds: VOCs are often toxic and their impact on the environment must be evaluated. The aim of this thesis work is the development of a laboratory method for identification and quantification of these emissions. The difficulty arises from the wide variety of compounds being potentially emitted. Moreover the desired method requires a high measurement rate ("real time") often incompatible with existing techniques. An analytical device coupling a furnace and a high-resolution mass spectrometer associated with a controlled chemical ionization method has been developed. This device is based on a low magnetic field FT-ICR compact mass spectrometer. The strengths of this technique are (i) high mass resolution allowing exact mass measurements, (ii) recording of the whole mass range simultaneously, allowing detection of a large variety of compounds. Controlled chemical ionization allows soft and quantitative ionization of molecules of interest. Proton transfer from H₃O⁺ ion (PTRMS) has shown its potentialities for VOC detection in many areas. After presenting the background and need, the developed experimental device is described in detail.The validation of this instrument for trace gas analysis has been performed at LPGP, using a nonthermal plasma depollution device. The results of acetaldehyde degradation according to operating conditions in the discharge reactor are presented.PTR ionization usually leads to the protonated molecule, so that identification is simplified. However fragmentations are sometimes observed. Use of a chemical ionization precursor ion heavier and less reactive than H₃O⁺ may minimize these drawbacks. Protonated difluorobenzene was selected as a precursor and its reactivity was tested and compared with H3O+ reactivity. In this purpose, kinetic studies were performed on a series of alcohols known for their fragmentation behavior with H₃O⁺. The results confirm the interest of the new precursor.Polymethyl methacrylate (PMMA) is a widespread material: plexiglass. Its degradation process is relatively simple since it consists in predominant depolymerization, along with formation of minor products. Consequently, PMMA study appeared interesting for method development and validation. Thermal degradation of PMMA has been studied under inert, then oxidative atmosphere conditions. The presented results include identification of minor products and mass balance under different temperature conditions. Real-time monitoring of VOC emission showed time differences in emission peaks of MMA monomer and minor products, each of them being emitted slightly later than MMA. Finally, a conclusive part presents the perspectives opened for this new method.

Pyrenophora tritici-repentis (Ptr) is the necrotrophic fungus responsible for tan spot of wheat (Triticum aestivum). Ptr causes disease on susceptible wheat cultivars through the production and secretion of host-selective toxins (HSTs). HSTs are compounds that are only known to be produced by fungi and considered to be primary determinants of pathogenicity. Infiltration of these toxins into sensitive wheat elicits the same symptoms as the pathogen, which simplifies investigations of host- pathogen interactions due to exclusion of the pathogen. These characteristics make HSTs ideal molecules to dissect molecular plant-microbe interactions. Known HSTs of Ptr include Ptr ToxA (ToxA), Ptr ToxB (ToxB) and Ptr ToxC (ToxC). ToxA is the most characterized toxin of Ptr, as well as the first proteinaceous HST identified. The proposed mode-of-action for ToxA includes internalization into sensitive wheat mesophyll cells, localization to the chloroplast, photosystem perturbations and elicitation of high amounts of reactive oxygen species (ROS), all of which lead to necrosis. However, it is still unknown how ToxA is transported to the chloroplast. To identify additional interacting components involved in ToxA symptom development, genes were silenced in tobacco plants (Nicotiana benthamiana) using the tobacco rattle virus (TRV) virus-induced gene-silencing (VIGS) system. Four genes were identified that potentially could play a role in ToxA-induced cell death: a 40S ribosomal subunit, peroxisomal glycolate oxidase (GOX), a thiamine biosynthetic enzyme (Thi1), and the R-gene mediator, Sgt1. Ptr exhibits a complex race structure determined by the HST(s) produced and the symptom(s) elicited on sensitive wheat cultivars. Currently, there are eight characterized races and other HSTs and races have been proposed. Isolate SO3 was discovered in southern Oregon and elicits ToxA-like symptoms on a wheat differential set, yet lacks the ToxA gene. The transcriptome of SO3 was sequenced, assembled, and aligned to a ToxA-producing isolate, Pt-1C-BFP, which will aid in the identification of the protein(s) that may be responsible for these ToxA-like symptoms. SO3 contains a set of 497 sequences that were not found in the ToxA-producing isolate Pt-1C-BFP (BFP). These sequences should be further investigated to identify those that encode small secreted proteins (SSPs) and could potentially serve as HSTs and pathogenicity factors of SO3. / Graduation date: 2013

The performance evaluation and parametric studies of an Inertance Tube Pulse Tube Refrigerator (IPTR) are performed for different length-to-diameter ratios, with the Computational Fluid Dynamics (CFD) package FLUENT. The integrated model consists of individual models of the components, namely, the compressor, compressor cooler, regenerator, cold heat exchanger, pulse tube, warm heat exchanger, inertance tube and the reservoir. The formulation consists of the governing equations expressing the conservation of mass, momentum and energy with axi-symmetry assumption and relations for the variable thermophysical properties of the working medium and the regenerator matrix, and friction factor and heat transfer coefficients in oscillatory flows. The local thermal non-equilibrium of the gas and the matrix is taken into account for the modeling of heat exchangers and the regenerator which are treated as porous zones. In addition, the wall thickness of the components is also accounted for. Dynamic meshing is used to model the compressor zone. The heat interaction between pulse tube wall and the oscillating gas, leading to surface heat pumping, is quantified. The axial heat conduction is found to reduce the overall performance. The thermal non-equilibrium results in a higher cold heat exchanger temperature due to inefficiencies. The dynamic characteristics of pulse tube are analyzed by introducing a time constant. The study is extended to other types of PTRs, namely, the Orifice type Pulse Tube Refrigerator (OPTR), Double Inlet type Pulse Tube Refrigerator (DIPTR) and a PTR with parallel combination of inertance tube and orifice (OIPTR). The focus of the second phase of analysis is the pulse tube region. The oscillatory flow and temperature fields in an open-ended pipe driven by a time-wise sinusoidally varying pressure at one end and subjected to an ambient-to-cryogenic temperature difference across the ends, is numerically studied both with and without the inclusion of buoyancy effects. Conjugate effects arising out of the interaction of oscillatory flow with heat conduction in the pipe wall are taken into account by considering a finite thickness wall with an insulated exterior surface. Parametric studies are conducted with frequencies in the range 5-15 Hz for an end-to-end temperature difference of 200 K. As the pressure amplitude increases, the temperature difference between the wall and the fluid decreases due to mixing at the cold end. The pressure amplitude and the frequency have negligible effect on the time averaged Nusselt number. The effect of buoyancy is studied for hot side up and cold side up configurations. It is found that the time averaged Nusselt number does not change significantly with orientation or Rayleigh number. Sharp changes in Nusselt number and velocity profiles and an increase in energy transfer through solid and gas were observed when natural convection comes into play with hot end placed down. Cooldown experiments are conducted on a preliminary experimental setup. Comparison of the numerical and experimental cooldown curves disclosed a number of areas where improvement is required, primarily the leakage past the piston and the design of the heat exchangers. The setup is being improved to bring out a second and improved version for attaining the lower cold heat exchanger temperature.

This thesis describes the on-road analysis of criteria air pollutants (CAPs) and volatile organic compounds (VOCs) from a moving vehicle. CAPs and VOCs have numerous direct and indirect effects on the environment and public health and are generated from a variety of point and diffuse sources. The concentration of these pollutants can vary on the scale of metres and seconds due to variable emission rates of sources, meteorology, and the topography of an area. CAPs are conventionally measured on a spatial scale of tens of kilometres and one hour or longer time resolution, which limits the understanding of their impact and leaving many communities lacking information regarding their air quality. VOCs are not measured as frequently as CAPs, owing to the difficulty, challenges, and cost associated with sampling. The Mobile Mass Spectrometry Lab (MMSL) was developed to collect high geospatial (15 – 1,500 m) and temporal (1 – 10 s) resolution measurements of CAPs (O3, NOx, PM2.5), CO2, CH4, and VOCs. CAPs and greenhouse gases were monitored using standard analyzers, while VOCs were measured using a proton-transfer reaction time-of-flight mass spectrometer (PTR-MS). PTR-MS is a real-time, direct, in situ technique that can monitor VOCs in the ambient atmosphere without sample collection. The PTR-MS monitored up to mass-to-charge 330 with a sample integration time of 1 or 10 seconds and had detection limits into the low- to mid-ppt. PTR-MS is a soft ionization technique that is selective to all compounds with a proton affinity less than water, which excludes the atmospheric matrix and includes most VOCs. The measurements provided by the PTR-MS provided a rich dataset for which to develop workflow and processing methods alongside sampling strategies for the collection of high geospatial and temporal VOC data. The first on-road deployment of the MMSL was performed across the Regional District of Nanaimo and the Alberni-Clayoquot Regional District in British Columbia, Canada, from July iv 2018 – April 2019 to monitor the geospatial and temporal variation in the concentration of CAPs and VOCs. VOCs detected in the areas include hydrocarbons like toluene, C2-benzenes, and terpenes, organic acids like acetic acid, oxygenated compounds like acetone and acetaldehyde, and reduced sulfur compounds like methanethiol and dimethyl sulfide. While observed concentrations of VOCs were mostly below detection limits, concentration excursions upwards of 2,200 ppb for C2-benzenes (reported as ethylbenzene) for instance, were observed across the various communities and industries that comprise central Vancouver Island. VOCs like monoterpenes, were observed near the wood industries up to 229 ppb. Combustion related VOCs, like toluene and C2-benzenes, were often observed on major transportation corridors and was found to vary significantly between seasons, with winter measurements often exceeding those made in the summer. Reduced sulfur compounds, common components of nuisance odours, were measured around a few industries like waste management and wood industries. The second on-road deployment of the MMSL focused on the analysis of VOCs in the community around a wastewater treatment plant (WWTP) to identify the source of odours in the area. VOCs were also monitored in the odour control process of the WWTP to identify the VOCs being emitted, how much were emitted, and where potential deficiencies were in the process in a unique study. Median emission rates at the facility for methanethiol, dimethyl sulfide, and dimethyl disulfide were determined to be 100, 19, and 21 kg yr-1, respectively. VOC monitoring in the community encompassed the WWTP and the other major industries in the area, including agricultural land, a composting facility, and a marina. The highest measurements of odorous reduced sulfur compounds were observed around the WWTP, upwards of 36 ppb for methanethiol. Unsupervised multivariate analysis was performed to identify groups of VOCs present and their potential sources. Three groups were identified, one of which was related to reduced sulfur compounds. This group was observed around the WWTP, indicating that the WWTP was the likely source of malodours in the community. / Graduate

Severe motor vehicle accidents (MVAs) represent one of the most often occurring psychological traumas, and are a leading cause of Posttraumatic Stress Disorder (PTSD). However, not all persons develop PTSD after traumatic events and a great proportion of patients who show symptoms initially recover over time. This has stimulated research of psychological and biological factors that explain development and maintenance of the disorder. Fortunately, this highly distressing condition can be effectively treated, e.g. via cognitive behavioral therapy (CBT). However, brain mechanisms underlying changes due to psychological therapy in PTSD are almost unknown (Roffman, Marci, Glick, Dougherty, & Rauch, 2005). On the other hand there are observations of positive changes following trauma called Posttraumatic Growth (PTG), which have stimulated research of associated psychological processes and factors. However, there is a lack of research about the relation of biological variables (e.g. measures of brain function) and PTG. Theories of brain asymmetry and emotion (Davidson, 1998b, 2004b; Heller, Koven, & Miller, 2003) propose that asymmetries of brain activation are related to certain features of human emotion (e.g. valence, approach or withdrawal tendencies, arousal). Whereas an enormous increase in the understanding of structural and functional abnormalities in PTSD could be achieved in the last decades due to neuroimaging research, there are still numerous unanswered questions. Especially, there is only little research explicitly examining activation asymmetries in PTSD. Furthermore, as mentioned, research is sparse investigating alterations of brain function that are associated with successful psychological treatment of PTSD. Finally, there is no published study examining how measures of brain function are related to PTG. This thesis presents 3 studies investigating electroencephalographic (EEG) asymmetries in survivors of severe motor vehicle accidents. The first part of the thesis (chapter 2) is devoted to a literature review about description (chapter 2.1), epidemiology (chapter 2.2 and 2.3), risk factors (chapter 2.4), psychological theories (chapter 2.5), biological mechanisms particularly neuroimaging findings (chapter 2.6), and treatment of PTSD (chapter 2.7.). Chapter 2.8 gives a short review on definition and research of Posttraumatic Growth. Chapter 2.9 provides an overview of models and research regarding brain asymmetry and emotion. In chapter 3.1, a study is presented that investigated hemispheric asymmetries (EEG alpha) among MVA survivors with PTSD, with subsyndromal PTSD, and without PTSD as well as non-exposed healthy controls during a baseline condition and in response to neutral, positive, negative, and trauma-related pictures (study I). Next, the findings of study II are presented (chapter 3.2). This study examined the effect of cognitive behavioral therapy on measures of EEG activity. Therefore, EEG activity before and after CBT in comparison to an assessment only Wait-list condition was measured. In chapter 3.3 a correlational study (study III) is presented that examined the relationship between frontal brain asymmetry and selfreported posttraumatic growth after severe MVAs. Finally, in chapter 4 the findings are summarized and discussed with respect to (1) the state/trait debate in frontal asymmetry research and (2) current psychological theories of PTSD and PTG. In addition, the use of neuroscientific research for psychotherapy is discussed. Suggestions are presented for future goals for “brain” research of PTSD and treatment of PTSD. / Schwere Verkehrsunfälle stellen eines der am häufigsten vorkommenden psychologischen Traumata dar, und sind eine Hauptursache der Posttraumatischen Belastungsstörung (PTBS). Jedoch entwickeln nicht alle Personen nach traumatischen Ereignissen eine PTBS und bei einem Großteil remittieren anfängliche PTBS-Symptome. Dies stimulierte die Erforschung von psychologischen und biologischen Faktoren, die die Entstehung und Aufrechterhaltung der PTBS erklären. Glücklicherweise kann die PTBS effektiv, z.B über die kognitive Verhaltenstherapie (KVT), behandelt werden. Jedoch sind Gehirnmechanismen, die mit klinischen Änderungen aufgrund der psychologischen Therapie in PTSD einhergehen, nahezu unbekannt (Roffman, Marci, Glick, Dougherty, Rauch, 2005). Auf der anderen Seite gibt es Berichte von positiven Änderungen nach traumatischen Ereignissen, die als Posttraumatische Reifung (PTR) bezeichent werden. Dies hat in kürzerer Vergangenheit die Forschung von verbundenen psychologischen Prozessen und Faktoren stimuliert. Jedoch gibt es kaum Untersuchungen über die Beziehung von biologischen Variablen (z.B Messungen der Gehirnfunktion) und PTR. Diese Arbeit präsentiert 3 Studien, die electroenzephalographische (EEG) Asymmetrien bei Opfern schwerer Verkehrsunfälle untersuchten. Der erste Teil der Arbeit (Kapitel 2) widmet sich einer Literaturrezension über: die Beschreibung (Kapitel 2.1), Epidemiologie (Kapitel 2.2 und 2.3), Risikofaktoren (Kapitel 2.4), psychologische Theorien (Kapitel 2.5), biologische Mechanismen besonders Neuroimaging Ergebnisse (Kapitel 2.6), und Behandlung der PTBS (Kapitel 2.7.). Kapitel 2.8 gibt einen kurzen Überblick über die Definition und Forschung zur Posttraumatischen Reifung. Kapitel 2.9 gibt eine Übersicht zu aktuellen Modellen und empirischen Befunden bezüglich Gehirnasymmetrien und Emotionen. Kapitel 3.1 präsentiert eine Studie, in der hemisphärische Asymmetrien (im EEG-Alpha Band) bei Unfallopfern mit PTBS, subsyndromaler PTBS, und ohne PTBS sowie gesunden Kontrollpersonen ohne Unfall untersucht wurden: während einer Ruhemessung und einer Emotionsinduktions-bedingung (neutrale, positive, negative und trauma-spezifische Bilder) (Studie I). Danach werden die Ergebnisse der Studie II (Kapitel 3.2) präsentiert. Hier wurde die Wirkung der kognitiven Verhaltenstherapie auf Messungen der EEG-Aktivität untersucht. Deshalb wurde EEG-Aktivität vor und nach einer KVT im Vergleich mit einer Warten-Gruppe gemessen. Kapitel 3.3 präsentiert eine Korellationsanalyse (Studie III), bei der die Beziehung zwischen der frontalen Gehirnasymmetrie und posttraumatischer Reifung untersucht wurde. Am Ende der Arbeit (Kapitel 4) werden die Ergebnisse zusammengefasst und in Bezug auf (1) die state/trait-Debatte im Rahmen der Asymmetrie-Forschung diskutiert sowie (2) ein Bezug zu aktuellen psychologische Theorien von PTSD und PTG hergestellt. Außerdem wird der Nutzen von neurobiologischer Forschung für die Psychotherapie besprochen. Dabei werden Vorschläge für zukünftige Projekte für die "Gehirn"-Forschung im Zusammenhang mit der PTBS, deren Behandlung und PTG gemacht.

Indiana University-Purdue University Indianapolis (IUPUI) Indiana University School of Dentistry Master Degree Thesis. / Detection of caries at an early stage is unequivocally essential for early preventive intervention. Longitudinal assessment of caries lesions, especially under the opaque preventive sealant, would be of utmost importance to the dental community. OBJECTIVES: The aim of this two-part in-vitro study is to evaluate the performance of multiple detection methods: The International Caries Detection and Assessment System (ICDAS); two quantitative light-induced fluorescence systems QLF; Inspektor™ Pro and QLF-D Biluminator™2 (Inspektor Research Systems B.V.; Amsterdam, The Netherlands); and photothermal radiometry and modulated luminescence (PTR/LUM) of The Canary System® (Quantum Dental Technologies; Toronto, Canada). All these are to be evaluated on their detection of caries on posterior human permanent teeth for 1) of primary occlusal lesions, and 2) under the sealant of primary occlusal lesions. METHODS: One hundred and twenty (N = 120) human posterior permanent teeth, selected in compliance with IU-IRB “Institutional Review Board” standards, with non-cavitated occlusal lesions ICDAS (scores 0 to 4) were divided into two equal groups. The second group (N = 60) received an opaque resin dental sealant (Delton® Light-Curing Pit and Fissure Sealant Opaque, Dentsply, York, PA). All lesions were assessed with each detection method twice in a random order except for ICDAS, which was not used following the placement of the sealant. Histological validation was used to compare methods in regard to sensitivity, specificity, % correct, and the area under receiver- operating characteristic curve (AUC). Intra-examiner repeatability and inter-examiner agreement were measured using intraclass correlation coefficient (ICC). RESULTS: 1) Of primary occlusal lesions, sensitivity, specificity, and AUC values were respectively: 0.82, 0.86 and 0.87 (ICDAS); 0.89, 0.60 and 0.90 (Inspektor Pro); 0.96, 0.57 and 0.94 (QLF-D Biluminator 2); and 0.85, 0.43 and 0.79 (The Canary System). Intra-examiner repeatability and inter-examiner agreement were respectively: 0.81 to 0.87: 0.72 (ICDAS); 0.49 to 0.97: 0.73 (Inspektor Pro); 0.96 to 0.99: 0.96 (QLF-D Biluminator 2); and 0.33 to 0.63: 0.48 (The Canary System). 2) Of primary occlusal lesions under the opaque dental sealants, sensitivity, specificity, and AUC values were respectively: 0.99, 0.03 and 0.67 (Inspektor Pro); 1.00, 0.00 and 0.70 (QLF-D Biluminator 2); and 0.54, 0.50 and 0.58 (The Canary System). Intra-examiner repeatability and inter-examiner agreement were respectively: 0.24 to 0.37: 0.29 (Inspektor Pro); 0.80 to 0.84: 0.74 (QLF-D Biluminator 2); and 0.22 to 0.47: 0.01 (The Canary System). CONCLUSION: Limited to these in-vitro conditions, 1) ICDAS remains the method of choice for detection of early caries lesion due to its adequately high accuracy and repeatability. QLF systems demonstrate potential in longitudinal monitoring due to an almost perfect repeatability of QLF-D Biluminator 2. The Canary System performance and repeatability were not acceptable as a valid method of early caries detection. 2) None of the methods demonstrated acceptable ability in detecting of occlusal caries under the opaque sealant. However, QLF-D Biluminator 2, with limitation to these in-vitro conditions and Delton opaque sealant, demonstrated a fair accuracy AUC (0.70) in detecting of caries under sealants at an experimental threshold of 12.5% ΔF.