Engineering of Cyclodextrin Product Specificity and pH Optima of the Thermostable Cyclodextrin Glycosyltransferase from Thermoanaerobacterium thermosulfurigenes EM1

The product specificity and pH optimum of the thermostable cyclodextrin glycosyltransferase (CGTase) from Thermoanaerobacterium thermosulfurigenes EM1 was engineered using a combination of x-ray crystallography and site-directed mutagenesis. Previously, a crystal soaking experiment with the Bacillus circulans strain 251 β-CGTase had revealed a maltononaose inhibitor bound to the enzyme in an extended conformation. An identical experiment with the CGTase from T. thermosulfurigenes EM1 resulted in a 2.6-Å resolution x-ray structure of a complex with a maltohexaose inhibitor, bound in a different conformation. We hypothesize that the new maltohexaose conformation is related to the enhanced α-cyclodextrin production of the CGTase. The detailed structural information subsequently allowed engineering of the cyclodextrin product specificity of the CGTase from T. thermosulfurigenes EM1 by site-directed mutagenesis. Mutation D371R was aimed at hindering the maltohexaose conformation and resulted in enhanced production of larger size cyclodextrins (β- and γ-CD). Mutation D197H was aimed at stabilization of the new maltohexaose conformation and resulted in increased production of α-CD. Glu258 is involved in catalysis in CGTases as well as α-amylases, and is the proton donor in the first step of the cyclization reaction. Amino acids close to Glu258 in the CGTase from T. thermosulfurigenes EM1 were changed. Phe284 was replaced by Lys and Asn327 by Asp. The mutants showed changes in both the high and low pH slopes of the optimum curve for cyclization and hydrolysis when compared with the wild-type enzyme. This suggests that the pH optimum curve of CGTase is determined only by residue Glu258.

The Effects of Transcranial Direct Current Stimulation (tDCS) on Auditory False Perceptions in Healthy Participants

Auditive verbale hallusinasjoner (AVH) har vært assosiert med hyperaktivitet i venstre temporoparietal cortex (TPC) og hypoaktivitet i venstre dorsolateral prefrontal cortex (DLPFC). Basert på disse funnene har det blitt foreslått at transkraniell direkte strømstimulering (tDCS), med den antatt eksitatoriske anoden og den antatte hemmende katoden plassert henholdsvis over venstre DLPFC og venstre TPC, kan lindre AVH. Til tross for lovende funn er imidlertid resultatene av denne behandlingen inkonsekvente. Målet med dette studie var å teste om en reversering av denne elektrode plasseringen hos friske deltakere ville føre til en omvendt effekt, det vil si økninger i auditive falske oppfatninger (H1). Dette vil kunne bekrefte det teoretiske grunnlaget for tDCS-behandlingen av AVH. I tillegg testet vi om flere auditive falske oppfatninger kunne utløses når deltakerne forventet visse ord (top-down-effekt) og når disse ordene var innebygd i menneskelig støy (bottom-up-effekt). Syttiseks deltakere ble testet to ganger, en gang med ekte og en gang med falsk tDCS. Trettini deltakere fikk elektrodeplasseringen som er brukt i behandlinger av AVH hos kliniske pasienter, mens trettisyv fikk omvendt elektrode plassering. Effekten av tDCS ble målt med en signaldeteksjonsoppgave (SDT) under hver økt. Vi klarte ikke å finne noen effekt av elektrodeplassering eller den forventete top-down/bottom-up interaksjonen. Mulige forklaringer på manglende funn, som at tDCS muligens ikke retter seg mot tiltenkte nevrale nettverk, presenteres.Masteroppgave i psykologiMAPSYK360INTL-KMDINTL-MEDMAPS-PSYKINTL-JUSINTL-MNINTL-HFINTL-PSYKINTL-S

Captured Waste: Drivers and barriers to the implementation of carbon capture and storage in the waste to energy industry

This thesis explores drivers and barriers to implementing carbon capture and storage in the waste to energy industry, and how this transformation is affected by contextual factors and preconditions. Additionally, it explores the role and strategy of actors involved in the transition. It has an emphasis on place-based factors. The study identified climate action, financing schemes and new business models that cover capital expenses and operational expenses, as well as learning outcomes as the primary drivers for CCS in WtE. At the same time, capital expenses and operational expenses were identified as primary financial barriers, requiring policies enabling a negative emission market and adjusting the CO2 emission tariff for the sector to enable profitability of CCS in WtE. Space limitations and issues of heat integration were also major barriers. Actors worked through networks to influence national politics, and to overcome placebased barriers. The findings provide empirical examples of regime alignment, triple embeddedness mediation, and highlight technical and physical challenges to implementing CCS in WtE. Finally, geography was conveyed through an emphasis on place-based factors, which showed a variance between the cases. At the general level, the findings of this thesis highlight the challenges of transforming hard-to-abate industries with CCS, and what measures actors involved are employing to increase the successfulness of these projects

Crisis at home and abroad

I denne oppgaven undersøker jeg hvordan flyktningkrisa fra 2015 økte oppslutningen til Sverigedemokratene (SD) og hvorfor responsen til de etablerte partiene slo feil. Dette er gjort gjennom å fokusere på konseptene tilbud og etterspørsel. Jeg anvender dokumentanalyse for å undersøke og avdekke hvorfor strategiene, dvs. Tilbudet, til Sosialdemokratene og Moderatene slo feil. For å vise en økende etterspørsel for en restriktiv innvandringspolitikk anvender jeg statistisk analyse. Den økte etterspørselen gjenspeiles i økt skepsis til innvanding og økende fremmedfientlige holdinger. Holdningsendringene er reflektert i statistikk, en diskursanalyse utført av Yantseva, samt de skiftende holdningene til partiet Moderatene. I den politiske kampen om velgere endret Moderatene holding fra en liberal innvandringspolitikk til å ta til orde for å begrense innvandring kraftig. Sosialdemokratene beskyttet prinsippene bak en liberal innvandringspolitikk mens de implementete lovendringer som begrenset innvandring. Strategiene falt derimot i SD sitt favør gjennom å øke prevalansen av innvandringsdebatten og styrke troverdigheten til SD sitt innvandringskritiske sysnpunkt. Jeg konkluderer med at flyktningkrisa fra 2015 er et godt eksempel på hvordan en hendelse kan påvirke den politiske status quo, og at politiske aktører spiller an avgjørende rolle i denne prosessen.This thesis examines how the Migration Crisis of 2015 furthered the Sweden Democrats’ (SD) electoral success and why the strategies of the mainstream parties failed. This is done through a demand-side and supply-side approach, using statistical analysis to explain the growing demand for a party opposing immigration and document analysis to examine how the supply of the Social Democrats and the Moderates failed. The thesis finds that opposition to immigration and nativist attitudes increased among Swedish constituents following the Crisis, increasing the demand for restricting immigration for which SD was the established proponent. The changes in attitudes were reflected in statistical evidence, a discourse analysis and in the changing attitudes of the Moderates. Additionally, I found the approach of the mainstream to benefit SD through increasing issue saliency and boosting the credibility of their critical views on immigration. I conclude that the Migration Crisis is a great example of how events may alter the political status quo in liberal democracies through altering demand and supply, and that political actors play a crucial role in this process

Fast fashion: an urgent global challenge

This research aims to explore why the fast fashion industry keeps growing despite growing knowledge about its environmental and social costs. The clothing industry is among the most unsustainable sectors in the global economy, accelerated by the fast fashion business model, and major changes in the industry are needed to be able to reach the Sustainable Development Goals (SDGs). In recent years, the industry and the public have become more aware of its negative impacts. However, the industry is still growing, and, with the current production and consumer patterns, this can have catastrophic outcomes for the planet. This research explores the real cost of fast fashion by looking at the negative externalities of the industry. Moreover, the study identifies the drivers of the market growth focusing on consumers, companies, and policy makers - three main actors in the sector.Universidad Europea de MadridGrado en Relaciones InternacionalesPresencia

The Response to Poverty in Three English Towns, 1560-1640: A Comparative Approach

This article compares poverty and poor relief in the Kentish towns of New Romney, Faversham and Sandwich. Each adopted quite distinct approaches and attitudes to the problems of urban indigence. In order to determine why these responses differed so markedly, three main variables are examined: economies and civic finances, religious inclinations and internal politics. Political variables, it is concluded, had the greatest impact on social welfare policies. Good relations between corporate authorities and those they ruled were essential to effective social relief. Cet article compare la pauvreté et l’assistance aux pauvres dans les trois villes du Kent, de New Romney, Faversham et Sandwich, chacune d’elles ayant adopté des attitudes et des approches très différentes face aux problèmes de l’indigence en milieu urbain. Afin de préciser les raisons pour lesquelles les réponses différaient si nettement, trois variables principales ont été examinées au niveau urbain : l’économie et les finances, les tendances religieuses et les politiques internes. Il en résulte que les variables de nature politique ont eu le plus d’impact sur les politiques d’assistance sociale. En effet, de bonnes relations entre les autorités municipales et ceux qu’elles gouvernaient étaient essentielles à la mise sur pied d’un système d’assistance sociale efficace. On peut espérer que ces conclusions sont largement applicables à d’autres communautés anglaises

Substrate-Assisted Catalysis Unifies Two Families of Chitinolytic Enzymes

Hen egg-white lysozyme has long been the paradigm for enzymatic glycosyl hydrolysis with retention of configuration, with a protonated carboxylic acid and a deprotonated carboxylate participating in general acid-base catalysis. In marked contrast, the retaining chitin degrading enzymes from glycosyl hydrolase families 18 and 20 all have a single glutamic acid as the catalytic acid but lack a nucleophile on the enzyme. Both families have a catalytic (βα)8-barrel domain in common. X-ray structures of three different chitinolytic enzymes complexed with substrates or inhibitors identify a retaining mechanism involving a protein acid and the carbonyl oxygen atom of the substrate’s C2 N-acetyl group as the nucleophile. These studies unambiguously demonstrate the distortion of the sugar ring toward a sofa conformation, long postulated as being close to that of the transition state in glycosyl hydrolysis.

Superradiance Transition in Photosynthetic Light-Harvesting Complexes

We investigate the role of long-lasting quantum coherence in the efficiency of energy transport at room temperature in Fenna-Matthews-Olson photosynthetic complexes. The excitation energy transfer due to the coupling of the light harvesting complex to the reaction center ("sink") is analyzed using an effective non-Hermitian Hamiltonian. We show that, as the coupling to the reaction center is varied, maximal efficiency in energy transport is achieved in the vicinity of the superradiance transition, characterized by a segregation of the imaginary parts of the eigenvalues of the effective non-Hermitian Hamiltonian. Our results demonstrate that the presence of the sink (which provides a quasi--continuum in the energy spectrum) is the dominant effect in the energy transfer which takes place even in absence of a thermal bath. This approach allows one to study the effects of finite temperature and the effects of any coupling scheme to the reaction center. Moreover, taking into account a realistic electric dipole interaction, we show that the optimal distance from the reaction center to the Fenna-Matthews-Olson system occurs at the superradiance transition, and we show that this is consistent with available experimental data.Comment: 9 page

Computational Methodologies and Physical Insights into Electronic Energy Transfer in Photosynthetic Light-Harvesting Complexes

We examine computational techniques and methodologies currently in use to explore electronic excitation energy transfer in the context of light-harvesting complexes in photosynthetic antenna systems, and comment on some new insights into the underlying physics. Advantages and pitfalls of these methodologies are discussed, as are some physical insights into the photosynthetic dynamics. By combining results from molecular modelling of the complexes (structural description) with an effective non-equilibrium statistical description (time evolution), we identify some general features, regardless of the particular distribution in the protein scaffold, that are central to light-harvesting dynamics and, that could ultimately be related to the high efficiency of the overall process. Based on these general common features, some possible new directions in the field are discussed.Comment: Invited Perspective Article for Phys. Chem. Chem. Phy

When I Was Young . .. - Perceptions of Past Winters by Elderly Residents of Northwest Wisconsin

Young people today often hear their eIders talk about the severe winters oftheir youth, noting colder, snowier times in the past. A survey of elderly residents of NW Wisconsin documents their perceptions of past winters. The results of this survey were then related to an nual and decade mean winter temperature and snowfal l data from the same region for the period, 1920 to 1996. It appears that memories of the most severe winter weather are connected with childhood. A majority of respondents chose the 1930s as being the coldest decade in memory. In reality, it was not. Only one subject chose the 1970s as being the coldest decade, which it was. Subjects tended to use one severe winter as their reference for the severity of an entire decade. For example, over 35 percent of subjects referred to the 1950s as being the snowiest when in fact the \u2750s produced the least snowfall overall. However, the winter of 1950-51 was exceptionally snowy across much ofthe upper Midwest. Most elderly people associated the most severe winters of their lives with the years in which they walked to school. In their comments the need to express the hardships of their youth is evident. Improved technology minimizes the perceived severity of recent winters. As technology advances, memories do not