774 Works

X-ray generation from and spectroscopy of a thin liquid sheet

Jonathan Charles Tobit Barnard
In this thesis a fan spray nozzle design is presented that is capable of producing single micrometer thick sheets of liquid, which are stable and flat. These sheets are characterised by various interferometric techniques, and some elementary fluid dynamics calculations are employed to understand the formation of the sheet. A new experimental vacuum chamber was designed and built, and the liquid sheet jet apparatus was installed into it and run successfully in the vacuum. Soft...

Mesh adaptation and adjoint methods for finite element coastal ocean modelling

Joseph Gregory Wallwork
Adjoint methods have become extremely useful tools for computational geoscience. In this thesis, the two main implementations – the continuous and discrete adjoint methods – are compared within the same code framework, Firedrake, in terms of accuracy, computational cost and usability. The discrete adjoint method is deemed best suited for use within gradient-based optimisation routines and is used to invert timeseries data for a tsunami source, with different automatic differentiation tools applied to the source...

The effect of food structure on energy intake and appetite regulation

Shatha Humoud Alrabiah
The beneficial effects of resistant starch on appetite regulation and body weight is well established in the literature; however, the underlying mechanism is not fully understood. Cell walls are the main source of resistant starch in human diets. Changes in dietary patterns over the recent years are dominantly characterised by highly-processed food, which commonly lack their cell-wall structure intact. Industrial processing can cause damage to the native structure of the cell wall, affecting nutrient bioavailability...

Novel therapeutic approaches with small activating RNA

Pinelopi Andrikakou
Oligonucleotide therapeutics is a major platform for drug discovery with great potential for diseases where endogenous gene expression is downregulated. In 2016, MTL-CEBPA was the first RNA activating oligonucleotide drug targeting CEBPA to enter clinical development for patients with advanced hepatocellular carcinoma (HCC). The aim of this PhD project is to develop new therapeutic small activating RNAs (saRNAs) for genes which are suppressed in the pathology of inflammation, Non-alcoholic Fatty Liver Disease (NAFLD) and Non-Alcoholic...

A novel role for the Escherichia coli RNA chaperone Hfq in the adaptive response to nitrogen starvation

Joshua McQuail
Nitrogen is an essential nutrient for bacterial survival and growth, being a constituent of almost all cellular building blocks, including nucleotides, amino acids, and cell wall components. The adaptive response to nitrogen starvation in Escherichia coli has been well characterised at the transcriptional level, but relatively little beyond that. Moreover, the role of post-transcriptional regulation of gene expression is being increasingly recognised as a vital facet of bacterial adaptive responses to stress. Therefore, the ubiquitous...

Environmentally assisted cracking on titanium alloys

Yitong Shi
Titanium alloys have been widely used as the structural components in gas turbine engines for aerospace applications, owing to the combined benefits of the high specific strength, good corrosion resistance and excellent fatigue properties at the temperature range 300-600 °C. Failure associated with AgCl-induced HSSCC was firstly identified in 1966, on a titanium compressor disc in a spin test. However, the reaction chemistry and cracking mechanisms have been rarely studied and still remain unknown. This...

Using biomechanics to define the role of the upper extremity in rowing performance

Caryn Alexa Urbanczyk
Performance and injury risk are strongly affected by an athlete’s ability to consistently execute effective rowing technique. Previous rowing biomechanics studies focused on kinematic descriptions of the lower extremity and lumbar spine. Detailed biomechanical analyses of the upper extremity during rowing are limited, despite repetitive, high intensity loading across the shoulder complex and the prevalence of long-lasting upper extremity overuse injuries. This thesis aims to examine upper body biomechanics in ergometer rowing (for performance enhancement...

Superhydrophobic surfaces: their hydrodynamic stability, thermal resistance and boundary layers

Samuel Tomlinson
It is known that an increased flow rate can be achieved in channel flows when smooth walls are replaced by superhydrophobic surfaces. Applications include the thermal management of microelectronics, where a competition between convective and conductive resistances must be accounted for to evaluate any advantages of these surfaces. Additionally, it is important to address the stability of the Cassie-Baxter state for future work. Fluid properties are central in such problems, and in applications; these can...

Sheathed cold-formed steel wall systems

Constantinos Kyprianou
Cold-formed steel members are widely used in the construction industry due to their versatility, high strength-to-weight ratio and ease of assembly. Stud columns set in tracks, form the main members in cold-formed steel wall systems, which are typically sheathed with plasterboard or oriented strand board (OSB). The interaction between the cold-formed steel members and the sheathing, which can have a significant effect on the ultimate strength and flexural stiffness due to composite action and bracing,...

Exploring ambient mass spectrometry capacities for rapid detection and phenotyping of pseudomonas aeruginosa infection in cystic fibrosis patients

Emmanuelle Bardin
Cystic fibrosis (CF) patients mostly succumb to respiratory failure, usually caused by Pseudomonas aeruginosa infection. Early, but not chronic, infection can be eradicated, mandating timely detection. However, current methods are insufficiently sensitive and unsuitable for children. This thesis explores the potential of novel ambient mass spectrometric (MS) tools for the phenotyping of P. aeruginosa and its detection in non-invasive samples. The hypotheses are that bacterial expression evolves as infection progresses and that the composition of...

Developing physiologically-based toxicokinetic models to assess human exposure to brominated flame retardants and herbicides

Alexander Cooper
PBTK models are mathematical representations of chemical absorption, distribution, metabolism and excretion (ADME). Each model parameter describes a physiological, physicochemical or biochemical process that affects ADME. Distributions can be assigned to parameters that describe population variability and uncertainty. In this project, PBTK models were developed and calibrated using Bayesian analysis to assess human population exposure to herbicides (picloram and haloxyfop) and a brominated flame retardant (TBBPA). These models allowed assessment of internal exposure at the...

A guide to building climate-financial scenarios for financial institutions

A Koberle, A Ostrovnaya & G Ganguly
This briefing considers how the financial sector can manage the risks associated with moving to a zero-carbon future. The paper outlines why it is essential for financial institutions to understand so-called climate transition scenarios, which explore this journey to a zero-carbon future. The paper also sets out a framework that financial institutions can use to construct, or understand and use, climate transition scenarios in the context of financial sector risk management.

Novel carbon-11 radiolabelling of organic and inorganic compounds using [11C]CS2: Towards applications in pet imaging

Sara Cesarec
This thesis investigates the reaction of [11C]carbon disulfide and ammonium [11C]thiocyanate for the preparation of 11C-labelled organic and inorganic molecules that have the potential to be used in positron emission tomography (PET) imaging. CS2 is a small and reactive molecule that, to date, has not been widely explored for the generation of 11C-labelled compounds. CS2 is known to react rapidly with amines and to form dithiocarbamate (DTC) molecules within minutes. This method therefore presents a...

Biologically-inspired machine learning approaches to large-scale neural data analysis

Pamela Hathway
Recent progress in recording techniques now allows researchers to record from hundreds and even thousands of neurons simultaneously. New, scalable methods need to be developed to handle such large data sets. Ideally these methods should not only analyse the multi-dimensional data, but also provide results which could be interpreted by the brain. One key problem in neuronal data analysis is to identify neuronal assemblies i.~e. groups of neurons displaying coordinated neuronal activity. Currently available methods...

Modelling and inference of spatio-temporal processes in Single Molecule Localisation Microscopy

Lekha Patel
Recent advancements in super-resolution microscopy have enabled cellular structures to be imaged beyond sub-diffraction limits. In order to do so, a widely used class of super resolution methods called single molecule localisation microscopy (SMLM) exploit the stochastic nature of fluorescent probes, or fluorophores, that move between bright and dark states until they permanently cease to transition. When observing a large number of fluorophores, this behaviour enables only a sparse subset of them to be detected...

Examples of G-Strand Equations

Darryl Holm & Rossen Ivanov

The preservation of lipid biosignatures in iron-rich environments on mars

Jonathan Tan
Past life on Mars, should it have existed, would have left behind fossilised organic biosignatures. Sample selection strategies for current and future life detection missions to Mars require an understanding of the processes that control the preservation, degradation, and detection of diagnostic organic fossil biosignatures in Martian environments over geological time. These include the deleterious effects of radiation, the increased temperatures and pressures associated with burial in the Martian subsurface, and the interactions between organic...

Fabrication and aplications of graphene hollow fibre membranes

Yunsi Chi
Graphene has attracted vast amount of research in the last decade. Attributed to its sp2 hybridisation, graphene is chemically inert, making it an ideal material to be used in extremely harsh conditions. Graphene’s ultra-thin property also makes it an ideal material for membrane separation because permeation is inversely proportional to membrane thickness. While many studies have been carried out on graphene membranes, scaling up remains a key challenge, designing graphene membrane in a geometry which...

Catalysis in flow: monoalkylation of ammonia with alcohols

Andrew Yuk Keung Leung
This PhD thesis describes the Ni-catalysed alkylation of ammonia with alcohols to achieve high selectivity to primary amines. This work was broadly divided into two parts: (i) developing and understanding reaction conditions through batch reactions; and (ii) deploying the system into a flow reactor and understanding how the system works and fails. Extensive screening of heterogeneous catalysts in the alkylation of ammonia with alcohols was carried out in batch reactors. It was found that a...

Understanding more about maternal vaccination and neonatal immunity to improve vaccine induced protection in early life

Ziyun Zhong
Neonates are more susceptible to infectious diseases and often have worse disease outcomes. Influenza virus, Respiratory Syncytial Virus (RSV) and Streptococcus agalacticae (Group B Streptococcus: GBS) are three major pathogens associated with neonatal infections. Maternal and neonatal vaccination are two promising strategies to protect this vulnerable population. Maternal influenza vaccination has been clinically proven to be effective in protecting both the mothers and newborns. However, the limited half-life of antibody response reduces the effectiveness of...

Investigating the role of non-coding RNAs in doxorubicin-induced cardiotoxicity

Long non-coding RNAs (lncRNAs) are emerging as important regulators in many biological processes. However, despite over thousands of lncRNAs have been identified, only a few have been functionally characterised, especially in cardiac diseases and development. The use of anthracyclines such as doxorubicin (DOX) has improved mortality and morbidity in cancer patients, yet associated risks of cardiomyopathy have limited their clinical application. DOX-induced cardiomyopathy (DIC) is frequently irreversible and typically progresses to heart failure. However, little...

Drivers underpinning heterogeneity in host-pathogen systems

Kieran Alexander Bates
The amphibian-infecting chytrid fungi, Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal) cause the disease chytridiomycosis and are major agents of global amphibian decline. Despite catastrophic species loss associated with outbreaks of these pathogens, there is within- and between-species heterogeneity in susceptibility to infection, of which our understanding is limited. In this thesis, I investigate the key factors underpinning disease outcome in amphibians. In particular, I focus on the importance of host microbial ecology and whether...

Engineering pseudovirions for large-scale targeted gene transfer and recombinant adeno-associated virus production

Paladd Asavarut
Gene transfer is a technology central to the development of gene therapy and expression of proteins and biological products necessary for designing and producing drug compounds or creating new research methodologies. Consequently, the field has experienced a large bottleneck in economic and time costs when viral vectors are involved. Over the past decade, recombinant mammalian viral vectors have been exploited for these purposes; however, the limitations in their native biology and production methods warrant new...

Carbon monoxide sensing in biological environments

Jonathan Alexander Robson
Chapter 1 reviews the literature surrounding gaseous small molecules and their sensors in biological environments. In particular, the biological relevance of CO is described, focusing on its production in the cell and role as a small signalling molecule. Development of carbon monoxide (CO) sensors has previously been limited to air and solution studies, however, the latest literature which highlights potential sensing applications in vitro and in vivo has been reviewed. Chapter 2 demonstrates a successful...

Transfer layer formation of high performance polymers, polymer blends and polymer composites

Annelise Jean-Fulcrand
Polymers and polymer-based composites have previously been used for tribological applications in systems where lubricants are deemed unfit. However, one of the main challenges faced by polymer-based components over the years, is their narrow operating temperature range and their poor resistance to frictional heating. In this work, the performance of two high performance polymers: Polyetheretherketone (PEEK) and Polybenzimidazole (PBI) were evaluated under high temperature and various test conditions. The poor perfor- mance of PEEK composites...

Registration Year

  • 2021
    774

Resource Types

  • Text
    774

Affiliations

  • Imperial College London
    774
  • Technological University Dublin
    3
  • University of Orléans
    1
  • French National Centre for Scientific Research
    1
  • Fraunhofer Institute for Applied Polymer Research
    1
  • University of Birmingham
    1
  • University of Cape Town
    1