VictorJuiz/thesis huggingface dataset:
Group 4 amidinate complexes as olefin polymerisation catalysts

This Thesis describes the syntheses, structure and olefin polymerisation capability of a series of group 4 ?1-amidinate-supported complexes. Chapter One introduces metal-catalysed polymerisation of olefins with emphasis on the development of homogeneous molecular catalysts. The evolution of ?post-metallocene? systems, cocatalysts and the chemistry of activation are explored providing context to the work detailed in subsequent chapters.
Chapter Two describes the synthesis and characterisation of new titanium cyclopentadienyl-amidinate diene complexes and corresponding B(C6F5)3-activated zwitterionic compounds. Their performance in small-scale ethylene-propylene-diene monomer (EPDM) copolymerisation is compared to that of a related dialkyl initiator. Some underlying chemistry of the diene/zwitterionic species is explored particularly in relation to the reversibility of zwitterion formation (activation).
Chapter Three details the synthesis and characterisation of a congeneric series of cyclopentadienyl-amidinate group 4 complexes. Combined crystallographic and DFT studies provide an insight into the nature of the amidinate-metal interaction as well as the bonding and conformational preference of the diene complexes described in Chapters Two and Three. The performance of these precatalysts in ethylene homo- and ethylene-propylene (EP) copolymerisation experiments is presented along with preliminary activation experiments giving enhanced understanding of the nature of the active species.
Chapter Four describes the synthesis and characterisation of a series of chelating cyclopentadienyl-amidinate complexes. Structural characterisation of these compounds combined with DFT calculations provide useful comparisons with the related non-ansa precatalysts. The EP and EPDM polymerisation performance of the bridged complexes is compared to a representative non-chelated precatalyst.
Chapter Five contains experimental details and characterising data for new compounds described in this Thesis.
CD Appendix provides crystallography .cif files.

Keywords: CATALYSIS
CHEMISTRY
POLYMERISATION
ORGANOMETALLIC
Advisor: Mountford, P
Spin-selective chemical reactions in radical pair magnetoreception

Many animals on earth need to navigate in their own environments for breeding and foraging. The ability to determine a correct heading and the current location for a migratory bird is critical for its survival. Animals that are sensitive to the Earth’s magnetic field can use it to obtain their direction of travel.
In 2000, a paper suggested that radical pair reaction could form the basis for magnetoreception in migratory birds and a flavoprotein, cryptochrome, was proposed as the candidate for the radical pair precursor. Recent in vivo experimental results strongly support the hypothesis that radical pairs formed in the eyes of migratory birds are responsible for their magnetic compass sense. Cryptochrome has also been located in the UV-cones in the retinas of two different species of bird.
Radical pairs in living cells are influenced mainly by Zeeman interaction, hyperfine interaction, rotational modulation, etc., and together they influence the recombination reactions of the radical pairs. This thesis considers the possible role of radical pairs in avian magnetoreception, using computer simulations of the quantum mechanical evolution of a radical pair under a variety of conditions.
Chapter 1 contains the introductions to spin chemistry, avian magnetoreception, and the mathematical description of the quantum evolution of a radical pair.
Chapter 2 describes the four different theoretical models for a general non-diffusion-controlled radical pair reaction and the product yields of a radical pair reaction predicted by these four models are analysed and compared.
Chapter 3 introduces a model for avian magnetoreception that integrates photoselection with the radical pair reaction and the model is used to predict the retinal patterns that a bird may be able to use for magnetoreception. The anisotropic singlet product yields of a radical pair comprises the flavin chromophore and the tryptophan of a cryptochrome are also presented in this chapter. A paper based on some parts of this chapter is published [1] in the Journal of The Royal Society Interface.
Chapter 4 describes a modified version of an algorithm that is used to calculate the product yields detected in a reaction yield detected magnetic resonance (RYDMR) experiment. The new algorithm is used to analyse the results of two sets of RYDMR experiments in which two radical pair systems, pyrene/1,3-dicyanobenzene and chrysene/1,4-dicyanobenzene, were used. The modulated detection technique used in the RYDMR experiments is also discussed in this chapter. A section of this chapter is published [2] in a paper in the journal Physical Chemistry Chemical Physics.
[1] Lau, J.C.S.; Rodgers, C.T.; Hore, P.J., J. R. Soc. Interface, 9 (77): 3329–3337, 2012 [2] Wedge, C.J.; Lau, J.C.S.; Ferguson, K.-A.; Norman, S.A.; Hore, P.J.; Timmel, C.R. Phys. Chem. Chem. Phys., 15 (38): 16043–16053, 2013

Keywords: Magnetoreception
Radical Pair Mechanism
Advisor: Hore, P
Electrochemical investigations of H2-producing enzymes

Hydrogenases are a family of enzyme that catalyses the bidirectional interconversion of H+ and H2. There are two major classes of hydrogenases: the [NiFe(Se)]- and [FeFe]-hydrogenases. Both of these benefit from characteristics which would be advantageous to their use in technological devices for H2 evolution and the generation of energy. These features are explored in detail in this thesis, with a particular emphasis placed on defining the conditions that limit the activity of hydrogenases when reducing H+ to produce H2. Electrochemistry can be used as a direct measure of enzymatic activity; thus, Protein Film Electrochemistry, in which the protein is adsorbed directly onto the electrode, has been employed to probe catalysis by hydrogenases.
Various characteristics of hydrogenases were probed. The catalytic bias for H2 production was interrogated and the inhibition of H2 evolution by H2 itself (a major drawback to the use of some hydrogenases in technological devices to produce H2) was quantified for a number of different hydrogenase. Aerobic inactivation of hydrogenases is also a substantial technological limitation; thus, inactivation of both H2 production and H2 oxidation by O2 was studied in detail. This was compared to inhibition of hydrogenases by CO so as to elucidate the mechanism of binding of diatomic molecules and determine the factors limiting inactivation. This allows for a preliminary proposal for the genetic redesigning of hydrogenases for biotechnological purposes to be made. Finally, preliminary investigation of the binding of formaldehyde, potentially at a site integral to proton transfer, opens the field for further research into proton transfer pathways, the structural implications thereof and their importance in catalysis.

Keywords: hydrogenase
protein film electrochemistry
H2 production
Advisor: Fraser, A
Interpersonal affective forecasting

This thesis investigates individual and interpersonal predictions of future affect and explores their relation to implicit theories of emotion, prediction recall, debiasing, and focalism. Studies 1, 2, and 3 assessed affect predictions to upcoming reasoning tests and academic results, and Studies 4, 5, and 6 concerned predictions for self-identified events. The first study investigated the influence of implicit theories of emotion (ITE; Tamir, John, Srivastava, & Gross, 2007) on impact bias and prediction recall manipulating ITE between participant pairs who predicted and reported their affective reactions to feedback on a test of reasoning skills. Neither impact bias nor recalled predictions were affected by the manipulation. Recalled affect predictions differed from original affect predictions, but were not influenced by experienced affect. Study 2 further investigated the effects of target event timing on impact bias and affect prediction recall. The results showed no differences between individual and interpersonal impact biases across conditions. Again, recalled predictions differed from original predictions, and were not influenced by experienced affect. Study 3 investigated the influence of prior information about impact bias on interpersonal affective forecasting involving real-world exam results. The results demonstrated no differences in predictions due to information, however, significantly less unhappiness was predicted for participants’ friends compared to self-predictions. Study 4 examined the effect of different de-biasing information on affective predictions. The results demonstrated no differences in affective predictions by condition and found that participants’ ITE were not associated to affect predictions. Study 5 examined individual and interpersonal affect predictions using a between-subjects design in place of the within-subjects design. The results demonstrated no differences between the affect predictions made for self and for friends, and ITE were not associated with predictions. Study 6 examined the impact bias in interpersonal affective forecasting and the role of focalism. The results demonstrated distinctions between individual and interpersonal affecting forecasting with individual impact bias for positive reactions for negative events and individual and interpersonal reverse impact bias for calm emotional reactions to positive events. Immune neglect was found not to be associated with predictions. Overall, the studies found evidence for similar individual and interpersonal predictions which are resistant to influence.

Keywords: focalism
Impact bias
memory
debiasing
Interpersonal affective forecasting
Implicit theories of emotion
Affective forecasting
biased recall
Advisor: Parkinson, B
Models of the transition regions and coronae of late-type stars

This thesis examines the structure and heating requirements of the outer atmospheres (the lower transition region, upper transition region and corona) of the five dwarfs χ1 Ori (G0V), ϵ Eri (K2V), ξ Boo A (G8V), α Cen A (G2V) and α Cen B (K0V), and the sub-giant Procyon (F5 IV-V).
Alternative fits to X-ray spectra of ten late-type dwarfs from ROSAT are made using the latest available versions of the radiative power loss codes of Raymond and Smith, Landini and Monsignori Fossi, and Mewe et al.. Differences between these codes are found to arise from the choice of atomic physics and the number of transitions included. The resulting coronal temperatures and emission measures are found to follow correlations proposed by Montesinos and Jordan (1993).
The lower transition region is modelled using observations made with the International Ultraviolet Explorer and up-to-date atomic data. Models of the upper transition region and corona are derived assuming a balance between the radiative and conductive losses. Wave pressure is included in these models for the first time. Recent observations with the Extreme Ultraviolet Explorer aid the choice of starting parameters. The calculations are carried out in plane parallel and spherically symmetric geometries. The models of the lower and upper transition region are then combined; the spherically symmetric models of the upper transition region fit more smoothly on to those of the lower transition region than do the plane parallel models. The new model of Procyon and new measurements of Ne resolve a previous discrepancy which led to suggestions that emission in the transition region is restricted in area.
The heating requirements are examined. In the five dwarfs, but not in Procyon, the conductive fluxes at the base of the upper transition region are found to exceed the radiative energy losses for the layers immediately below. In Procyon, it is shown that acoustic wave heating is a viable mechanism for heating the lower transition region and corona, while the correlation of coronal properties with the dynamo Rossby number suggest that magnetic heating models are more likely for the five dwarfs.
Essential amino acid depletion by embryonic stem cells as a mechanism of immune privilege

Mouse embryonic stem cells (ESCs) are capable of differentiating into any somatic cell type and are known to display fragile immune privilege in vivo and in vitro. The extent to which the depletion of essential amino acids (EAAs) by ESCs contributes to this phenomenon was investigated.
ESCs were found to express various enzymes capable of catabolising EAAs within the culture medium. In particular, depletion of threonine, valine and lysine was found to have significant impact on T cell proliferation and differentiation, biasing their polarisation towards a FoxP3+ T regulatory (Treg) phenotype. Supplementing ESC conditioned medium with these three EAAs alone rescued normal T cell proliferation, whereas artificially limiting their availability was sufficient to induce Treg cell differentiation to a level equivalent to general EAA depletion. The pattern of EAA catabolism by mouse ESC was shared by induced pluripotent stem cells, while mouse melanoma cell lines and human ESCs displayed distinct patterns of EAA depletion.
The cytosolic branched chain aminotransferase enzyme, Bcat1, catalyses the first step of branched chain amino acid catabolism (isoleucine, leucine and valine), and is highly expressed by both mouse and human ESCs. The contribution of this enzyme to the establishment of acquired immune privilege by ESC-derived tissues was, therefore, investigated. ESC lines were derived from mice lacking Bcat1 activity and were characterised. Bcat1−/− ESC lines displayed no difference to their wildtype counterparts (Bcat1LoxP) in terms of in vitro proliferation and their capacity to form teratomas in vivo. Furthermore, the loss of Bcat1 function had little impact on the inhibition of T cell proliferation in culture, ability to induce Treg cell commitment or their ability to prevent rejection by T cell receptor transgenic recipients, suggesting the minimal contribution of Bcat1 to the depletion of EAAs by ESCs.
In conclusion, EAA depletion by mouse ESC may provide a mechanistic explanation for the previously described immune-suppressive capacity of ESC.

Keywords: mouse embryonic stem cells
immune privilege
transplantation tolerance
Advisor: Fairchild, P
Seismological modelling of global earth structure

Upper mantle discontinuities from PP- and SS-precursors
The 410km discontinuity is examined using two global datasets of precursors to the PP and SS phases. The precursor amplitudes are used to constrain the impedance contrast, and examine lateral variations in the reflection coefficient of the discontinuity. P- and S-wave reflection amplitudes vary over different scale lengths, which could be due to the presence of melt, water or other chemical heterogeneities in the transition zone. Models for 410-topography are also derived, and the relationship between topography and transition zone seismic velocity anomalies examined. A moderate negative correlation exists between long wavelength 410-topography and transition zone velocity anomalies. However, when shorter wavelengths are included the relationship becomes more complex, and in some regions positive correlations are seen. This suggests that long wavelength variation of discontinuity topography and seismic velocity, is due to thermal effects. However, at shorter wavelengths the influence of chemical heterogeneities becomes important. Different spectra for thermal and chemical heterogeneity suggests that chemical anomalies can survive in convecting mantle.
Lower mantle reflectors and S-wave scattering
The lowermost mantle is investigated using a phase stripping technique and two migration methods: a backprojection, and a scheme with weights based on the Generalised Radon Transform. Resolution of the results is tested by migrating synthetic datasets. In some regions the results can be simulated using fairly simple distributions of point scatterers, but elsewhere the results require more complicated structures. The results identify several important properties of the D" region including reflectors within the D" region and a complex pattern of positive and negative scattering potentials near the core-mantle boundary. The results also show the presence of an intermittent D" discontinuity which is not a continuous, nor a global, feature. This suggests that the D" discontinuity is caused by either localised structures, such as thermal or chemical heterogeneity, or a global boundary with a variable impedance contrast.

Advisor: Woodhouse, J
Essays on development economics

This thesis is a collection of essays on the relevance of property right reforms on the wellbeing of poor households in developing countries; specifically titling programmes in urban Peru. The first essay assesses the effects of titling on housing investment. The availability of a unique dataset permits us to trace households' investment behaviour. This allows us to investigate if tenure security induces households to make sizeable investments, the evolution of this effect over time, and whether heterogeneous expectations about future tenure security matter for the estimated impact. Evidence reveals significant effects, especially on large investment; however, the response on this type of investment may take several years to become effective. The second essay contributes to the debate on the sustainability of property rights reforms by emphasising the importance of strong registration systems. Policymakers have focused on the process of granting titles but the conditions needed to maintain the formality of future plot transactions have been left unattended. The analysis exploits an exogenous variation in legislation to examine the impact of a change in the registration process on the registration rate of plot transactions. Evidence suggests a large negative effect, implying that a weak registration system could threaten the reform. The third essay explores the impact of titling on the risk preferences of slum dwellers. The analysis provides evidence that titled dwellers reported lower values of the risk aversion measure than their non-treated counterparts. Results also suggest that tenure security can influence slum dwellers' preference formation process. Evidence shows that beneficiaries who were exposed to tenure security during their youth report on average lower values of the risk aversion indicator than individuals titled at an older age.

Keywords: Development
Property Rights
Impact Evaluation
Titling
Economics
Advisor: Dercon, S
So ist Freihet nicht zu retten

This work is an effort to develop an interpretative framework for Kant's political philosophy that will illuminate not merely the political philosophy itself, but will have the additional advantage of showing the integral rather than the peripheral connexion of that philosophy with Kant's wider philosophical concerns. In this sense the essay is not an extended explication or critical commentary on Kant's political theory so much as an attempt to establish a context within which such commentary might proceed.
The context which is suggested is Kant's anthropology, that is to say, his concept of persons, a notion which is foundational to both his political philosophy and the entire Critical philosophy. The difficulty with such an approach is that Kant no where develops in an explicit and extended fashion his concept of persons, and thus the essay is in one way an effort of recovery, first from the historical accounts of human origins and progress, next from the teleological theories of the third Critique and the Anthropology, then from the doctrine of man as end, and finally from Religion, of a systematic account of what Kant believes persons to be.
In all of these diverse efforts to make sense of man, it is argued that Kant's central concept for discussing persons is the idea of freedom, though depending on the context this notion is often linked to another, for instance, in the historical works with Nature, in the Groundwork with reason and morality, and in Religion with evil. Thus all of these other ideas become either extensions of or elucidations of freedom. The idea of Freedom as the foundation of personhood is, however, given its most crucial role in Kant's characterization of persons as ends in themselves. It is this doctrine which is foundational for much of subsequent Western political theory, and which is essential for Kant's political and moral theory. Chapters Three, Four, and Five are thus the core of the essay in that they suggest first that Kant's very strong claims about persons as ends will not work in terms of his own arguments and are rendered even more conceptually suspect in light of his subsequent account of radical evil, and second an alternative reading, proposed by Kant if not finally entirely accepted by him which might provide a more plausible foundation for his basic insights about persons.
Creative sparks: literary responses to electricity, 1830-1880

This thesis examines accounts of electricity in journalism, short stories, novels, poetry and instructional writings, composed between 1830 and 1880 by scientific investigators, popular practitioners and fiction authors. The writings are approached as diverse and often incongruous impressions of electricity, in which the use of figurative and narrative techniques brings into question distinctions between science and literature. It is proposed that the unusual combination of electricity’s historical characterisation as an elixir vitae, intense investigation by contemporary scientists, and close alliance with new technologies offered unique opportunities for imaginative speculation. The thesis contends that engaging with these conflicting characteristics created a synthesis of scientific, social and literary responses that defy epistemological and generic categorisation. Fictionality is approached in chapter two as a central feature of scientific conceptualisation, experiment and discovery, particularly in the work of Michael Faraday and James Clerk Maxwell. In chapters three and four, the landscape of popular non-fiction books and periodicals is mapped, to show the ways in which the period’s publication contexts and forums, reading patterns, and use of literary practices contributed to wider engagement with ideas about electricity. Chapters five and six focus on fiction writings, identifying parallels and divergences between actual electrical science and its fictional portrayal. Short stories are shown to have emphasised associations between electricity, neurosis, deformity and the occult, complicating contemporary scientific optimism and presenting electricity as an alluring yet dangerous phenomenon, which disordered the natural world and man’s relationship with it. These characteristics are identified further in the metaphorical references of several canonical novelists, in the exploitation of electricity, elixirs and power depicted by William Harrison Ainsworth and Edward Bulwer-Lytton, and through a case study of the text and reception of a popular novel about electricity by Benjamin Lumley. The thesis contends that electricity’s anomalous and protean nature produced distinctively hybrid responses that enhance our understanding of contemporary popular writing, its contexts and how it was read.

Keywords: Ainsworth
James Clerk Maxwell
Bulwer-Lytton
Michael Faraday
nineteenth-century
periodicals
Victorian
electricity
elixir vitae
fiction
short stories
Lumley
Advisor: Whitworth, M