Photoconducting cdse powder for flat panel displays

The initial aim of this work was the preparation of sensitized photoconductor layers for use in conjunction with d.c. electroluminescent panels to develop an optically triggered bistable system for sustaining pixel states during the frame time of dynamically addressed flat panel displays. More than 200 CdSe powder samples and devices were prepared in attempts to achieve the required response speed of approximately 1 millisecond and photocurrent density of at least 10mA cm(^-2) under expected operating conditions. Powder samples were sensitized by various dopant incorporation and heat treatment processes. Copper and halogen ions were introduced in the form of dilute solutions. Correlations between preparation conditions and photoelectronic behaviour were sought, additional information being obtained from various physical and chemical analytical techniques. Devices were prepared from sensitized powder samples by compression, sintering or mixing with a nitrocellulose binder. A screen printing process was employed to deposit powder-binder layers 40-70 microns in thickness. Although an optically triggered bistable element was not experimentally demonstrated, sensitized powder characteristics were successively improved to within an order of magnitude of those required. Response times of 2 - 10 milliseconds were recorded, and photo-response in a sandwich type powder-binder device was finally achieved with photocurrent density of approximately 100mA cm(^-2). Simple power law relationships between conductivity and applied voltage, pressure and photoexcitation intensity were experimentally established. Prolonged ball milling of CdSe powder was found to cause a wurtzite to sphalerite phase transition which was reversible by firing in air for 2 hours at 500ºC. The estimated sphalerite lattice parameter was 6.051A. Long term variations in sample conductivities and photosensitivies were attributed primarily to oxygen adsorption in the presence of water vapour during storage. Photoelectronic characteristics indicative of both oxygen photoadsorption and photodesorption were observed, and explained in terms of dopant levels. Photoconductive processes in sensitized CdSe powder were shown to be dictated principally by surface chemistry and inter particle contacts

Evidencing the Need to Broaden the Position of Trust Legislation to Include Sports Coaches

When an individual is in a position of trust over another person, the age of consent is raised from 16 to 18 in the United Kingdom. Currently, the definition of a Position of Trust is restricted to professions such as teachers, care workers and youth justice workers. Recent high-profile cases have contributed to a growing consensus amongst key stakeholders of the need to broaden this legislation to include other roles, such as a sports coach. This study represents the first investigation into the number of concerns recorded by local authorities across England and Wales regarding sexual relationships between a person who is in a potential Position of Trust which is not currently covered by the legislation and someone who was aged 16 or 17 years old. Freedom of Information Requests resulted in full responses from 142 out of the 172 local authorities. A total of 653 cases were recorded over a 4-year period. The most prevalent of the identified roles were related to sport, however, roles related to religion, youth work, transport and uniform services were also cited. Regional differences regarding the number of cases recorded are highlighted and the implications of these findings are discussed

Fractional total colourings of graphs of high girth

Reed conjectured that for every epsilon>0 and Delta there exists g such that the fractional total chromatic number of a graph with maximum degree Delta and girth at least g is at most Delta+1+epsilon. We prove the conjecture for Delta=3 and for even Delta>=4 in the following stronger form: For each of these values of Delta, there exists g such that the fractional total chromatic number of any graph with maximum degree Delta and girth at least g is equal to Delta+1

Bimodal regulation of axonal transport by the GDNF-RET signalling axis in healthy and diseased motor neurons

Deficits in axonal transport are one of the earliest pathological outcomes in several models of amyotrophic lateral sclerosis (ALS), including SOD1G93A mice. Evidence suggests that rescuing these deficits prevents disease progression, stops denervation, and extends survival. Kinase inhibitors have been previously identified as transport enhancers, and are being investigated as potential therapies for ALS. For example, inhibitors of p38 mitogen-activated protein kinase and insulin growth factor receptor 1 have been shown to rescue axonal transport deficits in vivo in symptomatic SOD1G93A mice. In this work, we investigated the impact of RET, the tyrosine kinase receptor for glial cell line-derived neurotrophic factor (GDNF), as a modifier of axonal transport. We identified the fundamental interplay between RET signalling and axonal transport in both wild-type and SOD1G93A motor neurons in vitro. We demonstrated that blockade of RET signalling using pharmacological inhibitors and genetic knockdown enhances signalling endosome transport in wild-type motor neurons and uncovered a divergence in the response of primary motor neurons to GDNF compared with cell lines. Finally, we showed that inhibition of the GDNF-RET signalling axis rescues in vivo transport deficits in early symptomatic SOD1G93A mice, promoting RET as a potential therapeutic target in the treatment of ALS

Hierarchical Corannulene‐Based Materials: Energy Transfer and Solid‐State Photophysics

We report the first example of a donor–acceptor corannulene-containing hybrid material with rapid ligand-to-ligand energy transfer (ET). Additionally, we provide the first time-resolved photoluminescence (PL) data for any corannulene-based compounds in the solid state. Comprehensive analysis of PL data in combination with theoretical calculations of donor–acceptor exciton coupling was employed to estimate ET rate and efficiency in the prepared material. The ligand-to-ligand ET rate calculated using two models is comparable with that observed in fullerene-containing materials, which are generally considered for molecular electronics development. Thus, the presented studies not only demonstrate the possibility of merging the intrinsic properties of π-bowls, specifically corannulene derivatives, with the versatility of crystalline hybrid scaffolds, but could also foreshadow the engineering of a novel class of hierarchical corannulene-based hybrid materials for optoelectronic devices

Leukocyte CCR2 expression is associated with mini-mental state examination score in older adults

This is a copy of an article published in Rejuvenation Research © 2012 Mary Ann Liebert, Inc.; Rejuvenation Research is available online at: http://online.liebertpub.com.Circulating inflammatory markers may play an important role in cognitive impairment at older ages. Mice deficient for the chemokine (C-C motif) receptor 2 (CCR2) develop an accelerated Alzheimer-like pathology. CCR2 is also important in neurogenesis. To identify human gene transcripts most closely associated with Mini-Mental State Examination (MMSE) scores, we undertook a genome-wide and inflammation specific transcriptome screen in circulating leukocytes from a population-based sample

The MAPS Adaptive Secondary Mirror: First Light, Laboratory Work, and Achievements

The MMT Adaptive Optics exoPlanet Characterization System (MAPS) is a comprehensive update to the first generation MMT adaptive optics system (MMTAO), designed to produce a facility class suite of instruments whose purpose is to image nearby exoplanets. The system's adaptive secondary mirror (ASM), although comprised in part of legacy components from the MMTAO ASM, represents a major leap forward in engineering, structure and function. The subject of this paper is the design, operation, achievements and technical issues of the MAPS adaptive secondary mirror. We discuss laboratory preparation for on-sky engineering runs, the results of those runs and the issues we discovered, what we learned about those issues in a follow-up period of laboratory work, and the steps we are taking to mitigate them.Comment: 22 pages, 22 images, 2 tables, submitted to SPIE Proceedings (Unconventional Imaging, Sensing and Adaptive Optics 2023 Conference

Naomi: a new modelling tool for estimating HIV epidemic indicators at the district level in sub-Saharan Africa.

INTRODUCTION: HIV planning requires granular estimates for the number of people living with HIV (PLHIV), antiretroviral treatment (ART) coverage and unmet need, and new HIV infections by district, or equivalent subnational administrative level. We developed a Bayesian small-area estimation model, called Naomi, to estimate these quantities stratified by subnational administrative units, sex, and five-year age groups. METHODS: Small-area regressions for HIV prevalence, ART coverage and HIV incidence were jointly calibrated using subnational household survey data on all three indicators, routine antenatal service delivery data on HIV prevalence and ART coverage among pregnant women, and service delivery data on the number of PLHIV receiving ART. Incidence was modelled by district-level HIV prevalence and ART coverage. Model outputs of counts and rates for each indicator were aggregated to multiple geographic and demographic stratifications of interest. The model was estimated in an empirical Bayes framework, furnishing probabilistic uncertainty ranges for all output indicators. Example results were presented using data from Malawi during 2016-2018. RESULTS: Adult HIV prevalence in September 2018 ranged from 3.2% to 17.1% across Malawi's districts and was higher in southern districts and in metropolitan areas. ART coverage was more homogenous, ranging from 75% to 82%. The largest number of PLHIV was among ages 35 to 39 for both women and men, while the most untreated PLHIV were among ages 25 to 29 for women and 30 to 34 for men. Relative uncertainty was larger for the untreated PLHIV than the number on ART or total PLHIV. Among clients receiving ART at facilities in Lilongwe city, an estimated 71% (95% CI, 61% to 79%) resided in Lilongwe city, 20% (14% to 27%) in Lilongwe district outside the metropolis, and 9% (6% to 12%) in neighbouring Dowa district. Thirty-eight percent (26% to 50%) of Lilongwe rural residents and 39% (27% to 50%) of Dowa residents received treatment at facilities in Lilongwe city. CONCLUSIONS: The Naomi model synthesizes multiple subnational data sources to furnish estimates of key indicators for HIV programme planning, resource allocation, and target setting. Further model development to meet evolving HIV policy priorities and programme need should be accompanied by continued strengthening and understanding of routine health system data