VictorJuiz/thesis huggingface dataset:
Origami-inspired honeycombs as energy absorbing materials

This thesis proposed a type of origami-inspired honeycombs for energy absorption. The major findings of this thesis were as follows.
First, a novel design of origami-inspired honeycomb with self-locking and stiffness gradient was proposed. The design used the concept of Miura-ori pattern to create the unique Miura-ori honeycomb, with a core layer being at the middle sandwiched by two secondary flange layers. The self-locking feature realized by the prior densification of the flanges increased the overall energy absorption whilst keeping the peak load low. It was found that properly designed honeycombs could reduce the peak force by more than 50% and meanwhile possess good specific energy absorption (SEA) in comparison with conventional square honeycomb.
Second, derivative Miura-ori-based honeycomb cores were used to create a family of hybrid origami honeycombs. Experimental and numerical results were presented to study the energy absorption capacity of the hybrid honeycombs. It was found that the hybridization could notably affect the peak load and SEA when compared to the individual cores that was constructed in the same form. Especially, it was seen that the hybridization built in a weak-strong-weak manner could reduce the peak force and meanwhile increase the energy absorption efficiency.
Third, the effects of dynamic loading on origami honeycombs were investigated numerically. The mechanical behaviors of derivative Miura-ori-based honeycombs, including the hybrid origami-honeycombs were studied under different compressive loading conditions. It was found that under dynamic loading condition, the hybrid origami-honeycomb with stiffness gradient in weak-strong-weak order could noticeably reduce the impact and transmitted force, and increase the energy absorption efficiency at the same time.
In conclusion, this thesis presented new paths for creating programmable energy absorbing materials with controllable mechanical properties.

Keywords: honeycomb
energy absorption
Origami
Advisor: You, Z
Targeting β-catenin to inhibit the Wnt pathway in colorectal cancer cell lines

In colorectal cancer (CRC), one of the post prevalent cancers, the Wnt signalling pathway is upregulated due to mutations in the key players Adenomatous polyposis coli (APC) and CTNNB1 (β-catenin). While intensive research efforts are being placed in blocking the Wnt pathway, no inhibitors are yet in clinical use. In this project, different strategies were assessed to target β-catenin protein-protein interactions (PPIs) with the aim to inhibit the Wnt pathway in CRC cell lines.
Through 2x2 statistical analyses of known microarray gene expression and mutation data and preliminary immunofluorescence imaging of β-catenin localisation in CRC lines, low E-cadherin expression was associated with a more nuclear β-catenin subcellular localisation (Chapter 3).
Three different approaches to target the Wnt pathway were described: firstly, small molecule inhibitors against the β-catenin/B cell lymphoma 9 (BCL9) interaction site were tested in vitro (Chapter 4). The compounds exhibited non-specific killing on a large panel of CRC cell lines and fibroblasts. Furthermore, the compounds were also shown to be albumin dependent, limiting their further development. In Chapter 5, the Intracellular Antibody Capture (IAC) methodology to identify intracellular single domain antibodies (sdAb) against β-catenin is described. Through a large variable-heavy (VH) single domain library screen, three sdAb against β-catenin were identified, but subsequentially shown to be non-specific binders. Lastly, a previously described llama single-domain antibody fragment (VHH) was further characterised in SW480 CRC cells (Chapter 6). The VHH was shown to inhibit T-cell factor (TCF)-mediated Wnt pathway transcription and the expression of the Wnt target genes ASCL2 and AXIN2. The VHH binding site was refined to the first three Armadillo repeats of β-catenin.
Overall, this work explores different routes of Wnt signalling inhibition by targeting β-catenin PPIs and discusses their advantages and potential limitations for further development (Chapter 7).

Advisor: Bodmer, W
Machine learning based financial statement analysis predicting the market reaction to earnings announcements

This thesis considers the question of whether machine learning models can utilise the data contained in past financial statements to predict the market reaction to a future earnings announcement. The theoretical motivation for this hypothesis is drawn from a literature review encompassing the research domains of financial statement analysis, and earnings forecasting.
For the empiric evaluation of the hypothesis, a range of machine learning models and traditional linear models are trained to predict the abnormal return of a stock following its earnings call based on 121 variables from the balance sheet, income-, and cashflow-statement. These quarterly financial statement variables for the entire North American stock market are taken from the Compustat FUNDQ data set between the years 1991 and 2017, and the critical problem of missing values in the data is addressed with a comprehensive pre-processing strategy. The abnormal stock return serving as the dependent variable is computed as the Buy-And-Hold Abnormal Return (BHAR) of a particular stock until 30 days after the earnings announcement.
The design of the experiments involves model setups formulated as regressions and classifications, which are evaluated using an out-of-time and out-of-sample test sample. For it, the models demonstrate an ability to predict the correct sign of the abnormal market reaction in the majority of the cases using a newly introduced metric called PC. Additionally, the model predictions are demonstrated to translate into positive quarterly returns when employed in a simulated trading strategy over the study period. These task-specific evaluation metrics confirm a superior performance of the random forest and neural network over traditional linear models like the Lasso regression.

Advisor: Calliess, JP
Amel-Zadeh, A
Roberts, S
Postcolonial identities in Russophone women’s writing from the Caucasus and central Asia

My project examines how post-Soviet women writers outside of Russia, namely those in the Caucasus and Central Asia, respond to the post- Soviet transition and define their post-Soviet identities. The starting position of my thesis is that the current developments in the post-Soviet region cannot be understood without reference to postcolonial theory and that, to a large extent, post-Soviet identity is a postcolonial identity. Using theoretical tools of postcolonial studies (Bhabha, Vizenor, Tlostanova, Mbembe, Haraway), my enquiry spans a wide array of topics which most distinguish Russophone women’s prose: post-Soviet ‘unhomely’ trauma, immigration, NGOs and utopias. Yet, all of these themes are interlinked because the social perspectives and representational strategies are shared. Victimisation is eschewed in terms of ludic auto- stereotyping, mischief, and various kinds of strategically significant folly or outsider commentary, and authors push boundaries in order to creatively engage with otherness, evoking different kinds of unusual, uncanny, or even inhuman, senses of self. The project considers Russian studies as an expanding, trans-geographical field, while also enriching postcolonial studies by expanding its Eurocentric hermeneutics to include territories that are at most debatably ‘European’.

Keywords: Russophone
Central Asia
Caucasus
Post-Soviet
Literature
Women's writing
Postcolonial
Advisor: Kelly, C
P-wave velocity structures under South America from multi-frequency tomography

This thesis presents P-wave tomographic images of mantle structures under South America and offers tectonic interpretations for the recovered features. To build this inversion, source time functions, a requirement for computing suitably realistic synthetic seismograms, were estimated from broadband waveforms of 3505 teleseismic earthquakes of magnitudes greater than 5.6, recorded between 1990 and 2016 by regional and global networks. Almost 5M traveltime anomalies were calculated using cross-correlation of synthetic and observed seismograms in eight frequency bands, with centre periods ranging from 30.0 to 2.7 seconds. Sensitivity kernels were calculated using finite-frequency theory. In order to better illuminate weakly sampled mantle regions, integrated traveltime picks from the International Seismological Centre's ISC-EHB catalogue were also included.
Two main features are inferred from the tomographic images under South America. First, extensive lower-mantle fast anomalies under north-western region of South America may indicate ancient intra-oceanic subduction settings, which might have occurred to the west of the western margin of the continent. Secondly, high velocity provinces beneath western margin of South America, which appears only in the upper mantle, is interpreted to imply a younger subduction history. This fast anomalies distribution is associated to the Andean segmentation which has been archived in the geological records.

Advisor: Sigloch, K
Nissen-Meyer, T
Electrophysiological signals for closed-loop deep brain stimulation in Parkinson’s disease

Continuous high-frequency deep brain stimulation (DBS) in the subthalamic nucleus (STN) is an established treatment for Parkinson’s disease (PD). Current developments focus on trying to widen the therapeutic window of such treatments. Closed-loop DBS, where stimulation is dynamically controlled by feedback from biomarkers of pathological brain circuit activity, is one such development. Numerous electrophysiological signals extracted from local field potentials (LFPs) or electrocorticography (ECoG) in the basal ganglia-thalamo-cortical circuit relate to symptom severity and have consequently been proposed as real-time biomarkers. These signals include phase-amplitude coupling, beta-oscillatory bursts, single neuronal firing patterns, and features of waveform morphology. The neuronal basis and interdependency of these signals, however, are poorly understood. To address this a two-fold approach was taken. First, subthalamic macro- and micro electrode recordings of LFPs and single unit activity were studied in human PD patients undergoing DBS-surgery. Simultaneously recorded ECoGs were analysed in order to relate previously proposed cortical biomarkers to subthalamic neuronal activity. Second, selective optogenetic stimulation of basal-ganglia or cerebellar receiving thalamus was deployed in rodents to investigate if cortical electrophysiological signals observed in PD could be generated from driving inputs to motor thalamus.
In human PD patients, phase-amplitude coupling in the STN was found to reflect the locking of spiking activity to network beta oscillations and this coupling increased progressively with beta-burst duration, suggesting subthalamic beta bursts to capture higher levels of input-output synchronisation. Furthermore, cortical beta bursts were associated with several other cortical and subthalamic biomarkers and cortical waveform sharpness was linked to subthalamic neuronal synchronisation. In rodents, cortical phase-amplitude coupling in the ECoG could be produced by driving basal-ganglia, but not cerebellar recipient thalamus. Thus, providing experimental evidence to a theory of a basal-ganglia-thalamic origin of cortical phase-amplitude coupling in PD. Overall, this thesis gives novel insights into the neuronal basis of electrophysiological biomarkers in PD with direct implications for future closed-loop DBS trials.

Keywords: Parkinson's Disease
Neuroscience
Deep brain stimulation
Computer brain interface
Closed-loop DBS
Brain modulation
Subthalamic nucleus
Advisor: Sharott, A
Brown, P
Building bridges, blurring boundaries: the contribution of multiethnic individuals to intergroup relations

Multiethnic people constitute an increasingly prominent share of the population in the UK and beyond. Nevertheless, most research on intergroup relations continues to focus on people on either side of a clearly defined group divide. The aim of this thesis is to integrate multiethnic populations into research on intergroup relations and to investigate a question that is often raised about multiethnic individuals: whether they build bridges between members of different monoethnic groups. Chapter 1 outlines the theoretical and empirical context of my research, as well as the multi-method approach adopted throughout this thesis. Across three empirical chapters, I then present research on monoethnic individuals’ context-level exposure to multiethnic people, and on their individual-level contact experiences with multiethnic friends. This thesis includes research conducted in England, South Africa, and the US, and combines experimental, social network, and multi-level survey data. Chapter 2 investigates whether the presence alone of multiethnic individuals in a social environment can improve relations between members of different monoethnic groups. I report that context-level exposure to multiethnic people is unlikely to affect monoethnic individuals’ intergroup relations. Chapter 3 addresses further the bridge- building potential of multiethnics by studying their location within friendship networks and how they are evaluated by monoethnics. I find that multiethnics tend to be evaluated with intermediate levels of favourability, that they often occupy broker positions within their friendship networks, but that this may have both positive and negative implications for intergroup relations. Chapter 4 focusses on monoethnic individuals’ contact experiences with multiethnic friends and suggests that the bridge-building potential of multiethnic individuals may be realised most effectively through direct and indirect intergroup contact. I discuss these findings further in Chapter 5, which also addresses the implications of my research for our understanding of intergroup relations in the increasingly heterogeneous societies of the 21st century.

Keywords: brokers
intergroup contact
prejudice reduction
intergroup friendship
social network analysis
multiethnic individuals
multiracial individuals
Advisor: Wölfer, R
Parkinson, B
Exploring the interface between endoplasmic reticulum stress and oncolytic adenoviruses

Oncolytic viruses represent an emerging approach to cancer therapy. However, better understanding of their interaction with the host cancer cell and approaches to enhance their efficacy are needed. Efficient protein folding is essential for normal cell function but is perturbed in many cancer types and in cells suffering viral infections, resulting in endoplasmic reticulum (ER) stress and the consequent induction of the unfolded protein response (UPR). However, the interactions between viral infection and UPR signalling are poorly understood and could potentially be exploited for enhancing therapeutic effect.
Here, we investigate the effect of chemically induced endoplasmic reticulum (ER) stress on the activity of the chimeric group B oncolytic adenovirus Enadenotucirev, its closely related parental virus Ad11p, and the archetypal group C wild-type adenovirus Ad5. We find that EnAd and Ad11p induce ER stress much more powerfully than Ad5 infection. We show that treatment of colorectal and ovarian cancer cell lines with thapsigargin or ionomycin caused an influx of Ca2+, leading to an upregulation in E1A transcript and protein levels. Increased E1A protein levels, in turn, increased levels of expression of the E2B viral DNA polymerase, genome replication, late viral protein expression, infectious virus particle production and cell killing during Enadenotucirev and Ad11p but not Ad5 infection.
The engineering of an EnAd virus armed with the ability to genetically knockdown the target of thapsigargin inhibition however did not result in enhanced replication. We then show that the effect of thapsigargin and ionomycin treatment was not due to the induction of ER stress, but rather the influx of extracellular Ca2+ and consequent increase in protein kinase C activity.
These results underscore the importance of Ca2+ homeostasis during adenoviral infection, indicate a novel signalling pathway between protein kinase C and E1A, and raise the possibility of using Ca2+ flux-modulating agents in the manufacture and potentiation of oncolytic virotherapies.

Advisor: Seymour, L
Lei-Rossmann, J
Brown, T
Topological moduli spaces, homological stability, and operads

This thesis consists of two relatively independent parts.
In the first part, we study operads with homological stability, which are topological operads that satisfy a homological stability condition. Despite the fact that these operads are in general very far from being E∞-operads, their algebras give rise to infinite loop spaces upon group completion. We show that under a mild condition on an operad with homological stability, one can naturally associate topologically enriched symmetric strict monoidal categories to its algebras such that the group completion of the algebra is weakly equivalent to the loop space on the classifying space of the associated category, which is evidently an infinite loop space. We also show that this new infinite loop space structure coming from the associated category is equivalent to the previously known infinite loop space structure on the group completion of the algebra.
The second part is concerned with quotients of mapping class groups Γg,1 of oriented surfaces with one boundary component by the subgroups ϕg,1(k) in their Johnson filtration. We show that the stable classifying spaces Z × B (Γ∞/ϕ∞(k))+ after Wuillen's plus-construction are infinite loop spaces, fitting into a tower of infinite loop space maps that interpolates between the infinite loop spaces Z × BΓ+∞ and Z × B (Γ∞/ϕ∞(1))+ ≃ Z × BSp(Z)+ . We also show that for each level k in the Johnson filtration, the homology of these quotients with suitable systems of twisted coeficients stabilises as the genus g of the surface tends to infinity.

Advisor: Tillmann, U
The relationship between theology and ethics in modern Christian thought

Contemporary Christian theologians and thinkers frequently acknowledge the importance of the relationship between theology and ethics. However, no real consensus exists concerning that relationship’s precise significance, and little work has been done to map the different approaches taken to it. Consequently, most treatments of the relationship proceed without sufficient critical interrogation of their assumptions, or awareness of possible alternatives. This produces further problems downstream for theological or ethical methodology.
The present thesis intends to rectify that deficiency. It first develops a typology of the three principal approaches taken in contemporary Christian thought with respect to the theology/ethics relationship. These are: (1) an interpretation of the relationship in terms of a dualism between theory and practice (“the theory/practice type”); (2) an endeavour to transcend the relationship through a third category which synthesises theology and ethics (“the metahistorical type”); and (3) an argument that theology and ethics reflect discrete aspects of a divinely revealed reality (“the theo ontological type”). I evaluate these approaches through readings of systematic, liberation and practical theologians and Christian ethicists, including Karl Barth, Clodovis Boff, Sarah Coakley, Gerhard Ebeling, John Finnis, Stanley Hauerwas, Bonnie Miller McLemore, Oliver O’Donovan and John Howard Yoder.
Following this diagnostic task, I outline a constructive way forward, by proposing a “critique of the Christian life”. I argue each type above has persisted not merely due to entrenched disciplinary divides in the modern theological academy, but also because it captures an essential facet of that life. No type, however, has obtained a monopoly, given other facets of the Christian life which the competing types have better preserved. Those facets are the responsibility of the Christian moral agent, the particular situations in which that agent is embedded, the coherence of the agent’s life, and that life’s distinctively Christian identity. A key error of modern Christian thought, accordingly, is either to disregard the irreducible integrity of each facet, or alternatively, to assume these facets can be considered apart from one another.

Advisor: Zachhuber, J
Dissecting Polo kinase recruitment to the centrosome

Polo kinase is a major regulator of the cell cycle. Polo is present at many different subcellular structures, including centrosomes. Centrosomes are formed when mother centrioles recruit pericentriolar material (PCM) around themselves. The PCM expands dramatically in preparation for mitosis, in a process that relies on Polo phosphorylation of the PCM protein Cnn. Polo is also known to regulate centriole disengagement, and Polo binding to the centriolar protein Sas-4 is crucial for Asl recruitment to daughter centrioles during their conversion into fully functional mothers.
The primary aim of my thesis was to fully characterise how Polo is recruited to centrosomes to perform its different functions. As a model, I use syncytial fly embryos. In addition to the previously known Polo binding site in Sas-4, I found that the PCM protein Spd-2 directly interacts with the PBD domain of Polo. While Spd-2 is not required for Polo recruitment to the centriole, it is crucial to recruit Polo to the PCM. I propose that this interaction is part of a Spd-2/Polo/Cnn positive feedback loop that drives mitotic PCM assembly. Furthermore, I found that a third protein (Ana1) is required for overall Polo recruitment to the centrosome. Ana1 has been previously linked to Asl recruitment and/or maintenance and centriole conversion. Losing Ana1-mediated Polo recruitment did not affect these processes, but it did severely hinder mitotic PCM expansion. I propose that, independently of its Asl-related role, Ana1 acts as a crucial reservoir of centriolar Polo. Thus, centriolar Polo recruited via Ana1 can phosphorylate Spd-2 to allow it to bind the PBD, in an example of Polo “self-priming”.

Advisor: Raff, J