With the emergence of online social networks (OSNs), the way people create and share information has changed, which becomes faster and broader than traditional social media. Understanding how... Show moreWith the emergence of online social networks (OSNs), the way people create and share information has changed, which becomes faster and broader than traditional social media. Understanding how information (both good and harmful) spreads through OSNs, as well as what elements drive the success of information diffusion, has significant implications for a wide range of real-world applications. In this thesis, we conduct research to analysis the diffusion of information in OSNs via using deep representation learning. Specifically, we aim to develop deep learning- based models to solve two specific tasks, i.e., information cascades modeling and rumor detection. Show less
Jong, T.A. de; Chen, X.; Jobst, J.; Krasovskii, E.E.; Tromp, R.M.; Molen, S.J. van der 2022
Stacking domain boundaries occur in Van der Waals heterostacks whenever there is a twist angle or lattice mismatch between subsequent layers. Not only can these domain boundaries host topological... Show moreStacking domain boundaries occur in Van der Waals heterostacks whenever there is a twist angle or lattice mismatch between subsequent layers. Not only can these domain boundaries host topological edge states, imaging them has been instrumental to determine local variations in twisted bilayer graphene. Here, we analyse the mechanisms causing stacking domain boundary contrast in Bright Field Low-Energy Electron Microscopy (BF-LEEM) for both graphene on SiC, where domain boundaries are caused by strain and for twisted few layer graphene. We show that when domain boundaries are between the top two graphene layers, BF-LEEM contrast is observed due to amplitude contrast and corresponds well to calculations of the contrast based purely on the local stacking in the domain boundary. Conversely, for deeper-lying domain boundaries, amplitude contrast only provides a weak distinction between the inequivalent stackings in the domains themselves. However, for small domains phase contrast, where electrons from different parts of the unit cell interfere causes a very strong contrast. We derive a general rule-of-thumb of expected BF-LEEM contrast for domain boundaries in Van der Waals materials. Show less
This thesis consists of five chapters on how to construct prediction sets for different types of data and models in a parametric or nonparametric Bayesian paradigm. The motivation of the models... Show moreThis thesis consists of five chapters on how to construct prediction sets for different types of data and models in a parametric or nonparametric Bayesian paradigm. The motivation of the models comes from applications in pharmaceutical manufacturing and quality control. Show less
Jong, T. A. de; Benschop, T.; Chen, X.; Krasovskii, E.E.; Dood, M.J.A. de; Tromp, R.M.; ... ; Molen, S.J. van der 2021
In twisted bilayer graphene (TBG) a moiré pattern forms that introduces a new length scale to the material. At the 'magic' twist angle of 1.1°, this causes a flat band to form, yielding emergent... Show moreIn twisted bilayer graphene (TBG) a moiré pattern forms that introduces a new length scale to the material. At the 'magic' twist angle of 1.1°, this causes a flat band to form, yielding emergent properties such as correlated insulator behavior and superconductivity [1-4]. In general, the moiré structure in TBG varies spatially, influencing the local electronic properties [5-9] and hence the outcome of macroscopic charge transport experiments. In particular, to understand the wide variety observed in the phase diagrams and critical temperatures, a more detailed understanding of the local moiré variation is needed [10]. Here, we study spatial and temporal variations of the moiré pattern in TBG using aberration-corrected Low Energy Electron Microscopy (AC-LEEM) [11,12]. The spatial variation we find is lower than reported previously. At 500°C, we observe thermal fluctuations of the moiré lattice, corresponding to collective atomic displacements of less than 70pm on a time scale of seconds [13], homogenizing the sample. Despite previous concerns, no untwisting of the layers is found, even at temperatures as high as 600°C [14,15]. From these observations, we conclude that thermal annealing can be used to decrease the local disorder in TBG samples. Finally, we report the existence of individual edge dislocations in the atomic and moiré lattice. These topological defects break translation symmetry and are anticipated to exhibit unique local electronic properties. Show less
The focus throughout this thesis will be on gathering fundamental studies of the detailed structure and composition of the electrode/electrolyte interface effect on the rate and mechanism of key... Show moreThe focus throughout this thesis will be on gathering fundamental studies of the detailed structure and composition of the electrode/electrolyte interface effect on the rate and mechanism of key electrocatalytic reactions. The first part (Chapter 2 and 3) of this PhD thesis is about the studies of the non-Nernstian dependence on pH of the step-related voltammetric peak on platinum surface. The combined experimental and computational studies prove the existence of the co-adsorbed alkaline metal cation (Li, Na, K, and Cs) and hydroxyl at step sites of a platinum electrode. The co-adsorbed alkaline metal cation weakens the hydroxyl adsorption which yielding the anomalous non-Nernstian dependence on pH of the step-related “hydrogen peaks”. The second part starts from Chapter 4 changes first to the study of adsorption processes on a Pd monolayer-modified Pt(111) surface. Chapter 5 deals with the mechanism of electrocatalytic oxidation of formic acid and reduction of carbon dioxide on this Pd monolayer-modified Pt(111) electrode. The work in Chapter 6 explores the effects of electrolyte composition and catalysts surface structure on formic acid oxidation reaction. Show less
By investigating the interaction between different types of nucleases (i.e. nicking versus cleaving), donor DNA structures and target chromatin environments, this thesis provides important insights... Show moreBy investigating the interaction between different types of nucleases (i.e. nicking versus cleaving), donor DNA structures and target chromatin environments, this thesis provides important insights into how to improve the three crucial parameters of genome editing: efficiency, specificity and fidelity. The work presented in this thesis expand the range of possibilities for high-fidelity genetic manipulation of human cells. Show less
Bronchopulmonary dysplasia is the most common complication when premature birth occurs at less than 28 weeks gestational age. The general aim of this thesis is to explore the therapeutic... Show moreBronchopulmonary dysplasia is the most common complication when premature birth occurs at less than 28 weeks gestational age. The general aim of this thesis is to explore the therapeutic potential of interventions in signaling pathways, involved in lung development and oxidative stress-induced lung injury, to prevent or attenuate BPD in a neonatal rat model, in which experimental BPD is induced by exposure to hyperoxia. The therapeutic potential of the targeting compounds of signaling pathways was investigated by studying their beneficial effects on contributing factors to severe experimental BPD pathology, including aberrant alveolar and vascular development, inflammation, fibrosis, coagulation, vascular remodeling, pulmonary arterial hypertension and right ventricular hypertrophy. We found ⑴angiotensin II type 2 receptor ligand PD123319 attenuates hyperoxia-induced lung and heart injury at a low dose in newborn rats; ⑵ Metformin attenuates hyperoxia-induced lung injury in neonatal rats by reducing the inflammatory response; ⑶ Deficiency or inhibition of lysophosphatidic acid receptor 1 protects against hyperoxia-induced lung injury in neonatal rats; ⑷Adult lysophosphatidic acid receptor 1-deficient rats with hyperoxia-induced neonatal chronic lung disease are protected against lipopolysaccharide-induced acute lung injury; ⑸ Bone morphogenetic protein 9 protects against neonatal hyperoxia-induced impairment of alveolarization and pulmonary inflammation. Show less
The GABAergic system has been implicated in the pathogenesis of various anxiety disorders. Pharmacological treatments, like benzodiazepines, have been proven to target the GABA(A) receptors and... Show moreThe GABAergic system has been implicated in the pathogenesis of various anxiety disorders. Pharmacological treatments, like benzodiazepines, have been proven to target the GABA(A) receptors and exert quick-onset anxiolytic effect in anxiety patients. However, the side effects of these non-selective GABA(A)ergic compounds, such as sedation, postural imbalance, or potential abuse, limit their use for clinical anxiolysis. Based on the understanding of benzodiazepines’ mechanism of action, the emergence of α2,3 subtype-selective GABA(A) modulator is expected to provide a novel pharmacological approach that alleviates anxiety symptoms but spares the common undesired side effects. Most of these compounds are still in early clinical development, in which stage proof-of-mechanism studies are usually performed in healthy volunteers. The findings from our studies consistently present a similar pattern in the pharmacodynamic effect profiles of the α2,3 subtype-selective GABA(A) modulators versus those of the non-selective full GABA(A) agonist, lorazepam. Future application of anxiogenic symptom provocation models that combine subjective measurements and/or neuroendocrine biomarker assays may provide further construct validity for clinical anxiolytic effects of α2,3 subtype-selective GABA(A) modulators. Also, such findings are expected to provide insights into the translation of preclinical pharmacological properties of α2,3-subtype-selective GABA(A)ergic compounds to clinical effects in anxiety patients through human pharmacology studies. Show less
