Electromagnetic properties of semiconducting metal oxides under external stimulation

The main aim of this thesis is to investigate the realtime and long term electrical properties of semiconducting pigments when exposed to light an other environmental stimuli. A novel rectangular microwave resonant cavity is introduced for measuring the realtime dielectric changes of thin foil samples containing lacqueur and pigment while being exposed to a mostly uniform ultraviolet light source. This in an improvement to the invasive resistive measurements usually used to characterise resistive thin films. It also gives an insight into the localized conductivity of the material compared to the bulk conductivity of a traditional measurement. A novel temperature correction technique is described which splits degenerate cylindrical cavity modes into a measurement and reference mode. This was tested using a water sample, and was found to be very effective. A simplified analytical method of interpreting the resonant frequencies for temperature correction was also described, and experiments performed to check it’s accuracy. The properties of two sets of photosensitive materials were investigated. Titanium Dioxide (TiO2), which is known for being a brilliant white pigment and effective photocatalyst, was investigated as a powder under ultraviolet, green and red light. It was also investigated during thermal and humidity exposure. The results showed that Anatase TiO2 was more photoactive than Rutile under UV light. A photocatalytic grade of TiO2 with a smaller particle size and Carbon doping didn’t show a large change in dielectric loss, however its initial loss was much larger than the other samples suggesting it was already excited from ambient light. A pigment grade of TiO2 with a surface treatment of aluminium, silicon and polysiloxane compunds was also analysed which almost no response to UV light. None of the samples showed significant changes under green and red light. A range of pigments called Iriotec ® 7000, which are based around Antimony doped Tin Oxide coated onto mica/quartz/talcum substrates, were investigated using the rectangular resonant cavity due to their unusual darkening when exposed to ultraviolet light. The microwave measurements also showed a semi-permanent increase in dielectric loss suggesting an increase in trapped charge states. The larger particle sizes were in general more conductive than the smaller ones, and the addition of quartz/talcum also increased the conductivity slightly. Finally the in house built software used to run these experiments was described, including its low level architecture and available features such as a retracking algorithm to keep the frequency sweep close to the resonant frequency of the mode being measured

Getting on to a PhD

Over the last decade, there has been a 25% rise in the number of students applying for doctoral-level study across the UK (Universities UK, 2017). Prior to committing to a PhD, applicants must make an informed decision as to whether working towards a PhD is valuable for them in terms of personal and professional development. By answering some of the most frequent questions asked by PhD applicants, this article aims to de-mystify common myths associated with doctoral-level study

Temperature correction using degenerate modes for cylindrical cavity perturbation measurements

Microwave cavity perturbation measurements are a useful way to analyze material properties. Temperature changes can be introduced during these measurements either intentionally or as a result of some other process. The microwave cavity itself also has a temperature-dependent response, which can affect the results. A common method to correct is to use another resonant mode separately to the measurement mode, which is not affected by the sample. Instead of using independent modes, this paper describes a method to use split degenerate TMm10 modes of cylindrical cavities. TMm10 consists of two modes with identical field patterns with a relative rotation between them and identical resonant frequencies. A strategically placed perturbation reduces the frequency of one of the TMm10 modes and affects the coupling of both modes by reconfiguring the fields. This can be used for temperature correction by placing a sample such that both modes are equally coupled. The lower frequency, the perturbed mode is used as a measurement mode. The higher mode is used as a reference for temperature correction as it is unaffected by the sample. This technique was verified by measuring the permittivity of pure water using an aluminum microwave cavity resonator at 3.96 GHz. The temperature was swept between 20 °C and 60 °C, and the results was verified against the literature

Who are the women who enrolled in the POSITIVE trial: A global study to support young hormone receptor positive breast cancer survivors desiring pregnancy

Càncer de mama; Desig d'embaràs; Dones jovesBreast cancer; Pregnancy desire; Young womenCáncer de mama; Deseo de embarazo; Mujeres jóvenesBackground Premenopausal women with early hormone-receptor positive (HR+) breast cancer receive 5–10 years of adjuvant endocrine therapy (ET) during which pregnancy is contraindicated and fertility may wane. The POSITIVE study investigates the impact of temporary ET interruption to allow pregnancy. Methods POSITIVE enrolled women with stage I-III HR + early breast cancer, ≤42 years, who had received 18–30 months of adjuvant ET and wished to interrupt ET for pregnancy. Treatment interruption for up to 2 years was permitted to allow pregnancy, delivery and breastfeeding, followed by ET resumption to complete the planned duration. Findings From 12/2014 to 12/2019, 518 women were enrolled at 116 institutions/20 countries/4 continents. At enrolment, the median age was 37 years and 74.9 % were nulliparous. Fertility preservation was used by 51.5 % of women. 93.2 % of patients had stage I/II disease, 66.0 % were node-negative, 54.7 % had breast conserving surgery, 61.9 % had received neo/adjuvant chemotherapy. Tamoxifen alone was the most prescribed ET (41.8 %), followed by tamoxifen + ovarian function suppression (OFS) (35.4 %). A greater proportion of North American women were <35 years at enrolment (42.7 %), had mastectomy (59.0 %) and received tamoxifen alone (59.8 %). More Asian women were nulliparous (81.0 %), had node-negative disease (76.2%) and received tamoxifen + OFS (56.0 %). More European women had received chemotherapy (69.3 %). Interpretation The characteristics of participants in the POSITIVE study provide insights to which patients and doctors considered it acceptable to interrupt ET to pursue pregnancy. Similarities and variations from a regional, sociodemographic, disease and treatment standpoint suggest specific sociocultural attitudes across the world.The POSITIVE trial and this work are sponsored by the IBCSG in non-North American countries and by the Alliance for Clinical Trials in Oncology in North America, with collaboration of the Breast International Group (BIG) cooperative groups and US National Clinical Trials Network groups

Best practice standards for the delivery of NHS infection services in the United Kingdom

Infection expertise in the NHS has historically been provided predominantly by hospital-based medical microbiologists responsible for provision of diagnostic services and advice to front-line clinicians. While most hospitals had consultant-led microbiology departments, infectious iiseases departments were based in a small number of specialist centres. The demand for infection expertise is growing in the NHS, driven by advances in medical care, increasing awareness of the impact of antibiotic resistant and healthcare associated infections and threats from emerging infectious diseases. At the same time diagnostic services are being reorganised into pathology networks. The Combined Infection Training (CIT) is delivering a consultant workforce with expertise both in laboratory diagnostic practice and delivery of direct patient care. These changes create challenges for delivery of high quality infection expertise equitably across the NHS. They also offer an opportunity to shape infection services to meet clinical and laboratory demands.To date there has not been an attempt to bring together a single set of best practice guidelines for the requirements of an infection service. This document sets out seven standards. These are written to be practical and flexible according to the diverse ways in which infection expertise may be required across the NHS. It has been prepared by the Clinical Services Committee of the British Infection Association drawing on published evidence and guidance where they exist and on the group’s extensive experience of delivering infection services in hospitals across the NHS. It was then refined with input from the RCP Joint Specialist committee (JSC) and the RCPath Specialist Advisory Committee (SAC) and through consultation with the RCPath membership. It has been endorsed by the Royal College of Pathologists and the Royal College of Physicians. It will be reviewed annually by the CSC and updated as additional evidence becomes available

Evaluating the cost implications of integrating SARS-CoV-2 genome sequencing for infection prevention and control investigation of nosocomial transmission within hospitals

OBJECTIVES: The COG-UK hospital-onset COVID-19 infection (HOCI) trial evaluated the impact of SARS-CoV-2 whole genome sequencing (WGS) on acute infection, prevention, and control (IPC) investigation of nosocomial transmission within hospitals. We estimated the cost implications of using the information from the sequencing reporting tool (SRT), used to determine likelihood of nosocomial infection in IPC practice. METHODS: We conducted a micro-costing approach for SARS-CoV-2 WGS. Data on IPC management resource use and costs were collected from interviews with IPC teams from 14 participating sites and used to assign cost estimates for IPC activities as collected in the trial. Activities included IPC specific actions following a suspicion of healthcare-associated infection (HAI) or outbreak, as well as changes to practice following the return of data via SRT. RESULTS: The mean per sample costs of SARS-CoV-2 sequencing was estimated at £77.10 for rapid and £66.94 for longer turnaround phases. Over the 3 months interventional phases, the total management cost of IPC-defined HAIs and outbreak events across the sites was estimated at £225,070 and £416,447, respectively. Main cost drivers were bed-day lost due to wards closures because of outbreaks followed by outbreak meetings and bed-day lost due to cohorting contacts. Actioning SRTs, the cost of HAIs increased by £5,178 due to unidentified cases and the cost of outbreaks lowered by £11,246 as SRTs excluded hospital outbreaks. CONCLUSIONS: Although, SARS-CoV-2 WGS adds to the total IPC management cost, additional information provided could balance out the additional cost, depending on identified design improvements and effective deployment

Observing the Evolution of the Universe

How did the universe evolve? The fine angular scale (l>1000) temperature and polarization anisotropies in the CMB are a Rosetta stone for understanding the evolution of the universe. Through detailed measurements one may address everything from the physics of the birth of the universe to the history of star formation and the process by which galaxies formed. One may in addition track the evolution of the dark energy and discover the net neutrino mass. We are at the dawn of a new era in which hundreds of square degrees of sky can be mapped with arcminute resolution and sensitivities measured in microKelvin. Acquiring these data requires the use of special purpose telescopes such as the Atacama Cosmology Telescope (ACT), located in Chile, and the South Pole Telescope (SPT). These new telescopes are outfitted with a new generation of custom mm-wave kilo-pixel arrays. Additional instruments are in the planning stages.Comment: Science White Paper submitted to the US Astro2010 Decadal Survey. Full list of 177 author available at http://cmbpol.uchicago.ed

PolyGR and polyPR knock-in mice reveal a conserved neuroprotective extracellular matrix signature in C9orf72 ALS/FTD neurons

Dipeptide repeat proteins are a major pathogenic feature of C9orf72 amyotrophic lateral sclerosis (C9ALS)/frontotemporal dementia (FTD) pathology, but their physiological impact has yet to be fully determined. Here we generated C9orf72 dipeptide repeat knock-in mouse models characterized by expression of 400 codon-optimized polyGR or polyPR repeats, and heterozygous C9orf72 reduction. (GR)400 and (PR)400 knock-in mice recapitulate key features of C9ALS/FTD, including cortical neuronal hyperexcitability, age-dependent spinal motor neuron loss and progressive motor dysfunction. Quantitative proteomics revealed an increase in extracellular matrix (ECM) proteins in (GR)400 and (PR)400 spinal cord, with the collagen COL6A1 the most increased protein. TGF-β1 was one of the top predicted regulators of this ECM signature and polyGR expression in human induced pluripotent stem cell neurons was sufficient to induce TGF-β1 followed by COL6A1. Knockdown of TGF-β1 or COL6A1 orthologues in polyGR model Drosophila exacerbated neurodegeneration, while expression of TGF-β1 or COL6A1 in induced pluripotent stem cell-derived motor neurons of patients with C9ALS/FTD protected against glutamate-induced cell death. Altogether, our findings reveal a neuroprotective and conserved ECM signature in C9ALS/FTD.</p