Characterisation and stability of MESFETs fabricated on amorphous indium-gallium-zinc-oxide.

Indium-Gallium-Zinc-Oxide (a-IGZO) is an amorphous oxide semiconductor that has been attracting increasing attention for use in flat panel display and optoelectronic applications. This is largely due to IGZO’s high mobility at low processing temperatures. In this thesis, IGZO films were successfully grown on polyethylene naphthalate (PEN) substrates by RF magnetron sputtering at room temperature. These films were flexible, transparent and had a good Hall mobility (5-12 cm2/Vs). High quality metal oxide Schottky contacts were fabricated on these as-grown IGZO/PEN films with on-off rectification ratios of up to 108. These were then used as the gate contacts in transparent metal semiconductor field effect transistors (MESFETs). The performance and device stability of these IGZO/PEN MESFETs were investigated via a series of stress tests in both dark conditions and under illumination at different wavelengths in the visible spectrum. During constant voltage stress testing under illumination, the threshold voltage shifted by -0.54 V and 0.38 V for negative and positive gate biasing, respectively. These shifts proved reversible when devices were left in dark conditions for extended periods of time. The effect of persistent photoconductivity after exposure to different illumination sources was examined, with three potential passivation coatings to reduce this unwanted effect explored. Transparent IGZO/PEN MESFETs with an absolute transmission of up to 75% were achieved with the use of ITO ohmic contacts. These devices survived mechanical bending down to a radius of 7 mm with negligible variation in on-current and threshold voltage. This allows for the possibility of incorporating their use in future applications such as flexible transparent electronics

Characterisation and stability of MESFETs fabricated on amorphous indium-gallium-zinc-oxide.

Indium-Gallium-Zinc-Oxide (a-IGZO) is an amorphous oxide semiconductor that has been attracting increasing attention for use in flat panel display and optoelectronic applications. This is largely due to IGZO’s high mobility at low processing temperatures. In this thesis, IGZO films were successfully grown on polyethylene naphthalate (PEN) substrates by RF magnetron sputtering at room temperature. These films were flexible, transparent and had a good Hall mobility (5-12 cm2/Vs). High quality metal oxide Schottky contacts were fabricated on these as-grown IGZO/PEN films with on-off rectification ratios of up to 108. These were then used as the gate contacts in transparent metal semiconductor field effect transistors (MESFETs). The performance and device stability of these IGZO/PEN MESFETs were investigated via a series of stress tests in both dark conditions and under illumination at different wavelengths in the visible spectrum. During constant voltage stress testing under illumination, the threshold voltage shifted by -0.54 V and 0.38 V for negative and positive gate biasing, respectively. These shifts proved reversible when devices were left in dark conditions for extended periods of time. The effect of persistent photoconductivity after exposure to different illumination sources was examined, with three potential passivation coatings to reduce this unwanted effect explored. Transparent IGZO/PEN MESFETs with an absolute transmission of up to 75% were achieved with the use of ITO ohmic contacts. These devices survived mechanical bending down to a radius of 7 mm with negligible variation in on-current and threshold voltage. This allows for the possibility of incorporating their use in future applications such as flexible transparent electronics

The brighter side of soils: quantum dots track organic nitrogen through fungi and plants.

Soil microorganisms mediate many nutrient transformations that are central in terrestrial cycling of carbon and nitrogen. However, uptake of organic nutrients by microorganisms is difficult to study in natural systems. We assessed quantum dots (fluorescent nanoscale semiconductors) as a new tool to observe uptake and translocation of organic nitrogen by fungi and plants. We conjugated quantum dots to the amino groups of glycine, arginine, and chitosan and incubated them with Penicillium fungi (a saprotroph) and annual bluegrass (Poa annua) inoculated with arbuscular mycorrhizal fungi. As experimental controls, we incubated fungi and bluegrass samples with substrate-free quantum dots as well as unbound quantum dot substrate mixtures. Penicillium fungi, annual bluegrass, and arbuscular mycorrhizal fungi all showed uptake and translocation of quantum dot-labeled organic nitrogen, but no uptake of quantum dot controls. Additionally, we observed quantum dot-labeled organic nitrogen within soil hyphae, plant roots, and plant shoots using field imaging techniques. This experiment is one of the first to demonstrate direct uptake of organic nitrogen by arbuscular mycorrhizal fungi

Identification of the Regulatory Logic Controlling Salmonella Pathoadaptation by the SsrA-SsrB Two-Component System

Sequence data from the past decade has laid bare the significance of horizontal gene transfer in creating genetic diversity in the bacterial world. Regulatory evolution, in which non-coding DNA is mutated to create new regulatory nodes, also contributes to this diversity to allow niche adaptation and the evolution of pathogenesis. To survive in the host environment, Salmonella enterica uses a type III secretion system and effector proteins, which are activated by the SsrA-SsrB two-component system in response to the host environment. To better understand the phenomenon of regulatory evolution in S. enterica, we defined the SsrB regulon and asked how this transcription factor interacts with the cis-regulatory region of target genes. Using ChIP-on-chip, cDNA hybridization, and comparative genomics analyses, we describe the SsrB-dependent regulon of ancestral and horizontally acquired genes. Further, we used a genetic screen and computational analyses integrating experimental data from S. enterica and sequence data from an orthologous regulatory system in the insect endosymbiont, Sodalis glossinidius, to identify the conserved yet flexible palindrome sequence that defines DNA recognition by SsrB. Mutational analysis of a representative promoter validated this palindrome as the minimal architecture needed for regulatory input by SsrB. These data provide a high-resolution map of a regulatory network and the underlying logic enabling pathogen adaptation to a host

The Burkholderia Genome Database: facilitating flexible queries and comparative analyses

Summary: As the genome sequences of multiple strains of a given bacterial species are obtained, more generalized bacterial genome databases may be complemented by databases that are focused on providing more information geared for a distinct bacterial phylogenetic group and its associated research community. The Burkholderia Genome Database represents a model for such a database, providing a powerful, user-friendly search and comparative analysis interface that contains features not found in other genome databases. It contains continually updated, curated and tracked information about Burkholderia cepacia complex genome annotations, plus other Burkholderia species genomes for comparison, providing a high-quality resource for its targeted cystic fibrosis research community

Amino Acid Uptake in Arbuscular Mycorrhizal Plants

We examined the extent to which arbuscular mycorrhizal (AM) fungi root improved the acquisition of simple organic nitrogen (ON) compounds by their host plants. In a greenhouse-based study, we used quantum dots (fluorescent nanoparticles) to assess uptake of each of the 20 proteinaceous amino acids by AM-colonized versus uncolonized plants. We found that AM colonization increased uptake of phenylalanine, lysine, asparagine, arginine, histidine, methionine, tryptophan, and cysteine; and reduced uptake of aspartic acid. Arbuscular mycorrhizal colonization had the greatest effect on uptake of amino acids that are relatively rare in proteins. In addition, AM fungi facilitated uptake of neutral and positively-charged amino acids more than negatively-charged amino acids. Overall, the AM fungi used in this study appeared to improve access by plants to a number of amino acids, but not necessarily those that are common or negatively-charged

Facilitating healthcare practitioners to deliver self-management support in adult cancer survivors: a realist review

Background: Supporting cancer survivors in self-management can empower them to take an active role in managing the long-term physical and psychosocial consequences of cancer treatment. Healthcare practitioners are key to supporting patients to self-manage, however, they do not routinely engage in these discussions. Objective(s): This review aimed to establish what works for whom and in what circumstances in relation to facilitating healthcare practitioners to provide self-management support in people living with long-term consequences of cancer treatment. Methods: The review follows five steps: define the review's scope, develop initial programme theories, evidence search, selection and appraisal, and data extraction and synthesis. Database searches of Medline, EMBASE, CINAHL, Scopus, PsycINFO, ERIC and AMED databases, to September 2019 were supplemented with practitioner surveys. Insights into the mechanisms that operate in particular contexts to produce successful outcomes were illustrated using realist programme theories, developed using the Theoretical Domains Framework. Data selection was based on relevance and rigour. Data were extracted and synthesised iteratively to illuminate causal links between contexts, mechanisms and outcomes. Results: Five programme theories were identified from 20 included articles and seven practitioner surveys: practitioners will engage patients in discussions about self-management if they have appropriate (1) knowledge and (2) consultations skills, (3) a clear understanding of their self-management support role and responsibilities, and if (4) organisational strategies and (5) health system configuration enable integration into routine care. The mechanisms facilitating practitioners to support self-management were practitioner confidence, mutual trust and shared responsibility between practitioners and cancer survivors, organisational prioritisation and ease of delivery of self-management support. Conclusion: The findings articulate the necessary components for embedding self-management support into routine cancer care. Operationalisation of these components into effective self-management support interventions will require reconfiguration of pathways and adaptation for local context, using strategies such as quality improvement and co-design to guide intervention development, implementation and evaluation

Realist review protocol for understanding the real-world barriers and enablers to practitioners implementing self-management support to people living with and beyond cancer

Introduction: Self-management support can enable and empower people living with and beyond cancer to take an active role in managing long-term consequences of cancer treatment. Healthcare professionals are key to promoting patients to self-manage, however, they do not routinely engage in these discussions. This review aims to understand what works for whom and in what circumstances in relation to practitioners engaging with supporting people living with and beyond cancer to self-manage long-term consequences of systemic anticancer treatment. Methods and analysis: We will follow five steps for undertaking the realist review: (1) define the review scope; (2) develop initial programme theories; (3) evidence search, (4) selection and appraisal and (5) data extraction and synthesis. We will combine an informal literature search with a theory-based approach, using the Theoretical Domains Framework, and stakeholder feedback to develop initial programme theories. We will search Medline, EMBASE, CINAHL, SCOPUS, PsycINFO, ERIC and AMED databases to September 2019, and supplement this with citation tracking, grey literature and practitioner surveys. Data selection will be based on relevance and rigour. Data will be extracted and synthesised iteratively, and causal links between contexts, mechanism and outcomes illuminated in the process. The results will be reported according to the Realist And Meta-narrative Evidence Syntheses: Evolving Standards (RAMESES) quality and publication standards Ethics and dissemination: We have received ethical approval through the Research Ethics Committee, Faculty of Medicine and Health Sciences, University of East Anglia (ref 201819 – 124). We will disseminate to the research community through conference presentations and a peer-reviewed journal article. We will work with health care organisations, cancer charities and patients to agree a strategy for disseminating to these groups. PROSPERO registration number: CRD4201912091

InnateDB: facilitating systems-level analyses of the mammalian innate immune response

Although considerable progress has been made in dissecting the signaling pathways involved in the innate immune response, it is now apparent that this response can no longer be productively thought of in terms of simple linear pathways. InnateDB (www.innatedb.ca) has been developed to facilitate systems-level analyses that will provide better insight into the complex networks of pathways and interactions that govern the innate immune response. InnateDB is a publicly available, manually curated, integrative biology database of the human and mouse molecules, experimentally verified interactions and pathways involved in innate immunity, along with centralized annotation on the broader human and mouse interactomes. To date, more than 3500 innate immunity-relevant interactions have been contextually annotated through the review of 1000 plus publications. Integrated into InnateDB are novel bioinformatics resources, including network visualization software, pathway analysis, orthologous interaction network construction and the ability to overlay user-supplied gene expression data in an intuitively displayed molecular interaction network and pathway context, which will enable biologists without a computational background to explore their data in a more systems-oriented manner