| 1. |
- Armitage, James M., 1974-
(författare)
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Modeling the global fate and transport of perfluoroalkylated substances (PFAS)
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Perfluoroalkylated substances (PFAS) are persistent contaminants that are widely distributed in the global environment. Despite the fact that these chemicals have been manufactured and used for over 50 years, there has been little scientific and regulatory interest until very recently. An important research priority over the past decade has been to gain a better understanding of the mechanisms and pathways explaining the presence of these compounds in remote regions. One explanation is related to the use and release of volatile precursor compounds which undergo atmospheric transport and are also susceptible to degradation to PFAS through gas phase reactions with radical species. The main purpose of this doctoral thesis was to investigate an alternative explanation, namely the long-range transport (LRT) of PFAS themselves, which have been released into the environment in substantial quantities during manufacturing and product use. Papers I – III explore the LRT potential of perfluorocarboxylic acids and perfluorocarboxylates and demonstrate that both oceanic and atmospheric transport are efficient pathways of dispersion from source to remote regions of the Northern Hemisphere. Oceanic transport of perfluorooctane sulfonate (PFOS) was shown to be an important process in Paper IV as well. The role of precursor transport and degradation to PFOS was also examined in this paper. The most interesting aspect of the fate and transport of PFOS precursors is the rapid response in ambient concentrations exhibited by these compounds in the model simulations following production phase-out. Since precursor compounds are known to degrade to PFOS in vivo, the modeling results demonstrate that this exposure pathway is a plausible explanation for the declining trends in PFOS concentrations reported for marine mammals in some remote environments.
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| 2. |
- Chen, Jr-Tai, 1982-
(författare)
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MOCVD growth of GaN-based high electron mobility transistor structures
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The present work was to improve the overall quality of GaN-based high electron mobility transistor (HEMT) epitaxial structures grown on semi-insulating (SI) SiC and native GaN substrates, using an approach called bottom-to-top optimization. The bottom-to-top optimization means an entire growth process optimization, from in-situ substrate pretreatment to the epitaxial growth and then the cooling process. Great effort was put to gain the understanding of the influence of growth parameters on material properties and consequently to establish an advanced and reproducible growth process. Many state-of-the-art material properties of GaN-based HEMT structures were achieved in this work, including superior structural integrity of AlN nucleation layers for ultra-low thermal boundary resistance, excellent control of residual impurities, outstanding and nearly-perfect crystalline quality of GaN epilayers grown on SiC and native GaN substrates, respectively, and record-high room temperature 2DEG mobility obtained in simple AlGaN/GaN heterostructures.The epitaxial growth of the wide bandgap III-nitride epilayers like GaN, AlN, AlGaN, and InAlN, as well as various GaN-based HEMT structures was all carried out in a hot-wall metalorganic chemical vapor deposition (MOCVD) system. A variety of structural and electrical characterizations were routinely used to provide fast feedback for adjusting growth parameters and developing improved growth processes.
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| 3. |
- ENGBERG, ARON
(författare)
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Walking on the Pages of the Word of God : Self, Land, and Text Among Evangelical Volunteers in Jerusalem
- 2016. - 1st
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- During the last thirty years, the Evangelical relationship with the State of Israel has drawn much academic and popular attention, particularly from historical, theological, and political perspectives. This dissertation engages with this literature but also complements it with an ethnographic account of the discursive practices of Evangelical Zionists through which, it is suggested, much of the religious significance of the contemporary state is being produced. The study is based on ethnographic fieldwork among Evangelical volunteer workers in Jerusalem, focusing on their stories about themselves, the land, and the biblical text. The volunteers are located at three Christian ministries in Jerusalem – the International Christian Embassy Jerusalem (ICEJ), theBridges for Peace (BFP), and the Christian Friends of Israel (CFI) – all of which consider their work in Israel a natural consequence of biblical promises to Israel and their responsibility as Christians to “bless the Jewish people”. After introducing the theoretical and socio-cultural context in which this study is located, Chapter Three analyses the volunteers’ “coming-to-Israel” stories and the ways in which agency and selftransformation are understood therein. The analysis suggests that the ritual-like performance of these narratives situates the encounter with Israel as a religious conversion process and Israel as a religious symbol. Chapter Four discusses the volunteers’ narrative production of Israel as a sacred space that has a unique ability to mediate divine presence. It also shows how Israel’s special status is being negotiated both in relation to the encounter with material realities and with ideas about religious fetishism. The final analytical chapter focuses on “biblical literalism” as a textual ideology and on how this ideology becomes manifest in discourses about Bible prophecy and the “Hebraic roots of Christian faith”. It is suggested that these two discursive domains are deeply embedded in contestations about the authenticity of Evangelical religious forms: while the former often serves as empirical evidence for the truth of the biblical scripture, the latter constructs a historical narrative within which Evangelical Zionism is positioned as a rediscovery of authentic biblical faith. Ultimately, this study suggests that the beliefs and practices of Evangelical Christians engaged with Israel not only represent a recalibration of the relationship between Christianity and Judaism and between faith and politicsthemselves, but also a more fundamental reordering of the ways in which God is understood to relate to the world. While deeply embedded in Evangelical narrative traditions, the ideational and physical encounter with Israel also requires a renegotiation of Evangelical religion. This process involves questions of biblical reading practices and the meanings of signs and their social functions, and it invites Evangelical Zionists to negotiate the proper location of human and divine agency as well as the relationship between materiality and divine presence. For the volunteers the “realization of Israel’s spiritual significance” is a highly transformative experience, but rather than being a definite rupture from the past it is part of a broader process of increasingreligious commitment.
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| 4. |
- Friedman, Mikaela, 1977-
(författare)
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Affibody molecules targeting the epidermal growth factor receptor for tumor imaging applications
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Tumor targeting and molecular imaging of protein markers specific for or overexpressed in tumors can add useful information in deciding upon treatment and assessing the response to treatment for a cancer patient. The epidermal growth factor receptor (EGFR) is one such tumor-associated receptor, which expression is abnormal or upregulated in various cancers and associated with a poor patient prognosis. It is therefore considered a good target for imaging and therapy. Monoclonal antibodies and recently also antibody fragments have been investigated for in vivo medical applications, like therapy and imaging. In molecular imaging a small sized targeting agent is favorable to give high contrast and therefore, antibody fragments and lately also small affinity proteins based on a scaffold structure constitute promising alternatives to monoclonal antibodies. Affbody molecules are such affinity proteins that are developed by combinatorial protein engineering of the 58 amino acid residue Z-domain scaffold, derived from protein A. In this thesis, novel Affibody molecules specific for the EGFR have been selected from a combinatorial library using phage display technology. Affibody molecules with moderate high affinity demonstrated specific binding to native EGFR on the EGFR-expressing epithelial carcinoma A431 cell line. Further cellular assays showed that the EGFR-binding Affibody molecules could be labeled with radiohalogens or radiometals with preserved specific binding to EGFR-expressing cells. In vitro, the Affibody molecule demonstrated a high uptake and good retention to EGFR-expressing cells and was found to internalize. Furthermore, successful imaging of tumors in tumor-bearing mice was demonstrated. Low nanomolar or subnanomolar affinities are considered to be desired for successful molecular imaging and a directed evolution to increase the affinity was thus performed. This resulted in an approximately 30-fold improvement in affinity, yielding EGFR-binding Affibody molecules with KD´s in the 5-10 nM range, and successful targeting of A431 tumors in tumor-bearing mice. To find a suitable format and labeling, monomeric and dimeric forms of one affinity matured binder were labeled with 125I and 111In. The radiometal-labeled monomeric construct, 111In-labeled-ZEGFR:1907, was found to provide the best tumor-to-organ ratio due to good tumor localization and tumor retention. The tumor-to-blood ratio, which is often used as a measure of contrast, was 31±8 at 24 h post injection and the tumor was clearly visualized by gamma-camera imaging. Altogether, the EGFR-binding Affibody molecule is considered a promising candidate for further development of tumor imaging tracers for EGFR-expressing tumors and metastases. This could simplify the stratification of patients for treatment and the assessment of the response of treatment in patients.
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| 5. |
- Pixton, Tonya S., 1974-
(författare)
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Expecting Happy Women, Not Detecting the Angry Ones : Detection and Perceived Intensity of Facial Anger, Happiness, and Emotionality
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Faces provide cues for judgments regarding the emotional state of individuals. Using signal-detection methodology and a standardized stimulus set, the overall aim of the present dissertation was to investigate the detection of emotional facial expressions (i.e., angry and happy faces) with neutral expressions as the nontarget stimuli. Study I showed a happy-superiority effect and a bias towards reporting happiness in female faces. As work progressed, questions arose regarding whether the emotional stimuli were equal with regard to perceived strength of emotion, and whether the neutral faces were perceived as neutral. To further investigate the effect of stimulus quality on the obtained findings, Study II was designed such that the facial stimuli were rated on scales of happy-sad, angry-friendly, and emotionality. Results showed that ‘neutral’ facial expressions were not rated as neutral, and that there was a greater perceived distance between happy and neutral faces than between angry and neutral faces. These results were used to adjust the detectability measures to compensate for the varying distances of the angry and happy stimuli from the neutral stimuli in the emotional space. The happy-superiority effect was weakened, while an angry-female disadvantage remained. However, as these results were based upon different participant groups for detection and emotional rating, Study III was designed to investigate whether the results from Studies I and II could be replicated in a design where the same participants performed both tasks. Again, the results showed the non-neutrality of ‘neutral’ expressions and that happiness was more easily detected than anger, as shown in general emotion as well as specific emotion detection. Taken together, the overall results of the present dissertation demonstrate a happy-superiority effect that was greater for female than male faces, that angry-female faces were the most difficult to detect, and a bias to report female faces as happy.
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