Incorporation of square-planar Pd2+ in fluorite CeO2 : hydrothermal preparation, local structure, redox properties and stability

The direct hydrothermal crystallisation at 240 °C of Pd2+-containing ceria is investigated to study the extent to which precious metal dopants may be introduced into the cubic fluorite lattice. Samples of composition Ce1−xPdxO2−δ, where 0 ≤ x ≤ 0.15 can be produced in which Pd is included within the CeO2 structure to give a linear lattice expansion. Attempts to produce higher Pd2+-substitution result in the formation of PdO as a secondary phase. Ce and Pd were determined to be in the +4 and +2 oxidation states, respectively, by X-ray absorption near edge structure, suggesting oxide deficiency as the mechanism of charge balance. Extended X-ray absorption fine structure (EXAFS) analysis at the Pd K-edge reveals that Pd2+ has local square-planar coordination, as expected, and that a structural model can fitted in which the average fluorite structure is maintained, but with Pd2+ sitting in the square faces of oxide ions present in the local cubic geometry of Ce. This model, consistent with previous modelling studies, gives an excellent fit to the EXAFS spectra, and explains the observed lattice expansion. Transmission electron microscopy analysis shows that Pd is well dispersed in the nanocrystalline ceria particles, and in situ powder XRD shows that upon heating in air the samples remain stable up to 800 °C. H2-TPR shows that Pd-substitution leads to low temperature (<200 °C) reduction of the oxide, which increases in magnitude with increasing Pd-substitution. On prolonged heating, however, the Pd is lost from the ceria lattice to give dispersed Pd metal, suggesting an inherent instability of Pd-doped CeO2

Track Reconstruction Progress from the DMTPC Directional Dark Matter Experiment

he Dark Matter Time Projection Chamber (DMTPC) collaboration is developing prototype detectors to measure both the energies and directions of nuclear recoils. The intended application is to exploit the expected directional anisotropy of dark matter velocities at Earth to unambiguously observe dark matter induced recoils. The detector consist of low-pressure CF[subscript 4] TPC's with CCD cameras, PMT's, and charge amplifiers for readout. This talk gives an overview of the experiment and describes recent advances in hardware and analysis

Children's Book Awards in Australia: Their Effects on the Literary Marketplace

This study explores the outcomes resulting from the formal recognition of selected children's literature in Australia for six stakeholder cohorts. For the purposes of this research, the recognition was in the form of a children's or young adult literary award. The process leading to an award is documented in policies, reports and handbooks and some publicity is evident in the media, journals, online sources and popular literary magazines. However, the outcomes of this personal, corporate, organizational, social, cultural and economic activity have not been examined to date and this research project addresses the question of exactly what happens to the selected stakeholders after the winning announcement is made. Out of the general focus question there arose subsidiary questions relating to the strength of the impacts, the longevity of the impacts, the current knowledge of a range of awards and responses in terms of income or impressions of award related promotional activity. Selecting meaningful and relevant populations to survey and to clarify relevance and vocabulary in questioning involved a pilot study and resulted in a survey structure of six cohorts to represent the affected field. The survey method involved mailed questionnaires. In the construction of the questionnaires it was apparent that cohort-specific questionnaires would be necessary for there were very few avenues of questioning which were common across all cohorts. As these questionnaires were developed the research design evolved into six mini-projects which had some elements in common but also unique features and perspectives. The evolution of book awards over time is explored in this work. Recognition and dedicated publishing of Australian children's literature slowly developed out of children's literature published in Great Britain, the mother country. This thesis briefly follows this growth and development of literary works for children and the awarding of prizes for exceptional quality, revealing the shifts in perception of the nature of the child reader and society's perception of what constitutes a quality child's book in Australia. Book awards for children's literature did not arise spontaneously but were an expression of interest, respect and maturity in the development of Australian literature

Diagnostic omission errors in acute paediatric practice: impact of a reminder system on decision-making

BACKGROUND: Diagnostic error is a significant problem in specialities characterised by diagnostic uncertainty such as primary care, emergency medicine and paediatrics. Despite wide-spread availability, computerised aids have not been shown to significantly improve diagnostic decision-making in a real world environment, mainly due to the need for prolonged system consultation. In this study performed in the clinical environment, we used a Web-based diagnostic reminder system that provided rapid advice with free text data entry to examine its impact on clinicians' decisions in an acute paediatric setting during assessments characterised by diagnostic uncertainty. METHODS: Junior doctors working over a 5-month period at four paediatric ambulatory units consulted the Web-based diagnostic aid when they felt the need for diagnostic assistance. Subjects recorded their clinical decisions for patients (differential diagnosis, test-ordering and treatment) before and after system consultation. An expert panel of four paediatric consultants independently suggested clinically significant decisions indicating an appropriate and 'safe' assessment. The primary outcome measure was change in the proportion of 'unsafe' workups by subjects during patient assessment. A more sensitive evaluation of impact was performed using specific validated quality scores. Adverse effects of consultation on decision-making, as well as the additional time spent on system use were examined. RESULTS: Subjects attempted to access the diagnostic aid on 595 occasions during the study period (8.6% of all medical assessments); subjects examined diagnostic advice only in 177 episodes (30%). Senior House Officers at hospitals with greater number of available computer workstations in the clinical area were most likely to consult the system, especially out of working hours. Diagnostic workups construed as 'unsafe' occurred in 47/104 cases (45.2%); this reduced to 32.7% following system consultation (McNemar test, p < 0.001). Subjects' mean 'unsafe' workups per case decreased from 0.49 to 0.32 (p < 0.001). System advice prompted the clinician to consider the 'correct' diagnosis (established at discharge) during initial assessment in 3/104 patients. Median usage time was 1 min 38 sec (IQR 50 sec – 3 min 21 sec). Despite a modest increase in the number of diagnostic possibilities entertained by the clinician, no adverse effects were demonstrable on patient management following system use. Numerous technical barriers prevented subjects from accessing the diagnostic aid in the majority of eligible patients in whom they sought diagnostic assistance. CONCLUSION: We have shown that junior doctors used a Web-based diagnostic reminder system during acute paediatric assessments to significantly improve the quality of their diagnostic workup and reduce diagnostic omission errors. These benefits were achieved without any adverse effects on patient management following a quick consultation

Validation of Tool Mark Comparisons Obtained Using a Quantitative, Comparative, Statistical Algorithm

A statistical analysis and computational algorithm for comparing pairs of tool marks via profilometry data is described. Empirical validation of the method is established through experiments based on tool marks made at selected fixed angles from 50 sequentially manufactured screwdriver tips. Results obtained from three different comparison scenarios are presented and are in agreement with experiential knowledge possessed by practicing examiners. Further comparisons between scores produced by the algorithm and visual assessments of the same tool mark pairs by professional tool mark examiners in a blind study in general show good agreement between the algorithm and human experts. In specific instances where the algorithm had difficulty in assessing a particular comparison pair, results obtained during the collaborative study with professional examiners suggest ways in which algorithm performance may be improved. It is concluded that the addition of contextual information when inputting data into the algorithm should result in better performance

Denitri®cation in a nitrogen-limited stream ecosystem.

Abstract. Denitrification was measured in hyporheic, parafluvial, and bank sediments of Sycamore Creek, Arizona, a nitrogen-limited Sonoran Desert stream. We used three variations of the acetylene block technique to estimate denitrification rates, and compared these estimates to rates of nitrate production through nitrification. Subsurface sediments of Sycamore Creek are typically well-oxygenated, relatively low in nitrate, and low in organic carbon, and therefore are seemingly unlikely sites of denitrification. However, we found that denitrification potential (C &amp; N amended, anaerobic incubations) was substantial, and even by our conservative estimates (unamended, oxic incubations and field chamber nitrous oxide accumulation), denitrification consumed 5-40% of nitrate produced by nitrification. We expected that denitrification would increase along hyporheic and parafluvial flowpaths as dissolved oxygen declined and nitrate increased. To the contrary, we found that denitrification was generally highest at the upstream ends of subsurface flowpaths where surface water had just entered the subsurface zone. This suggests that denitrifiers may be dependent on the import of surface-derived organic matter, resulting in highest denitrification rate at locations of surface-subsurface hydrologic exchange. Laboratory experiments showed that denitrification in Sycamore Creek sediments was primarily nitrogen limited and secondarily carbon limited, and was temperature dependent. Overall, the quantity of nitrate removed from the Sycamore Creek ecosystem via denitrification is significant given the nitrogen-limited status of this stream

Reconstitution of full‐thickness skin by microcolumn grafting

Abstract In addition to providing a physical barrier, skin also serves a diverse range of physiological functions through different specialized resident cell types/structures, including melanocytes (pigmentation and protection against ultraviolet radiation), Langerhans cells (adaptive immunity), fibroblasts (maintaining extracellular matrix, paracrine regulation of keratinocytes), sweat glands (thermoregulation) and hair follicles (hair growth, sensation and a stem cell reservoir). Restoration of these functional elements has been a long‐standing challenge in efforts to engineer skin tissue, while autologous skin grafting is limited by the scarcity of donor site skin and morbidity caused by skin harvesting. We demonstrate an alternative approach of harvesting and then implanting μm‐scale, full‐thickness columns of human skin tissue, which can be removed from a donor site with minimal morbidity and no scarring. Fresh human skin microcolumns were used to reconstitute skin in wounds on immunodeficient mice. The restored skin recapitulated many key features of normal human skin tissue, including epidermal architecture, diverse skin cell populations, adnexal structures and sweat production in response to cholinergic stimulation. These promising preclinical results suggest that harvesting and grafting of microcolumns may be useful for reconstituting fully functional skin in human wounds, without donor site morbidity. © 2016 The Authors Journal of Tissue Engineering and Regenerative Medicine Published by John Wiley & Sons Ltd

Evolution of the Bovine TLR Gene Family and Member Associations with Mycobacterium avium Subspecies paratuberculosis Infection

Members of the Toll-like receptor (TLR) gene family occupy key roles in the mammalian innate immune system by functioning as sentries for the detection of invading pathogens, thereafter provoking host innate immune responses. We utilized a custom next-generation sequencing approach and allele-specific genotyping assays to detect and validate 280 biallelic variants across all 10 bovine TLR genes, including 71 nonsynonymous single nucleotide polymorphisms (SNPs) and one putative nonsense SNP. Bayesian haplotype reconstructions and median joining networks revealed haplotype sharing between Bos taurus taurus and Bos taurus indicus breeds at every locus, and specialized beef and dairy breeds could not be differentiated despite an average polymorphism density of 1 marker/158 bp. Collectively, 160 tagSNPs and two tag insertion-deletion mutations (indels) were sufficient to predict 100% of the variation at 280 variable sites for both Bos subspecies and their hybrids, whereas 118 tagSNPs and 1 tagIndel predictively captured 100% of the variation at 235 variable sites for B. t. taurus. Polyphen and SIFT analyses of amino acid (AA) replacements encoded by bovine TLR SNPs indicated that up to 32% of the AA substitutions were expected to impact protein function. Classical and newly developed tests of diversity provide strong support for balancing selection operating on TLR3 and TLR8, and purifying selection acting on TLR10. An investigation of the persistence and continuity of linkage disequilibrium (r2≥0.50) between adjacent variable sites also supported the presence of selection acting on TLR3 and TLR8. A case-control study employing validated variants from bovine TLR genes recognizing bacterial ligands revealed six SNPs potentially eliciting small effects on susceptibility to Mycobacterium avium spp paratuberculosis infection in dairy cattle. The results of this study will broadly impact domestic cattle research by providing the necessary foundation to explore several avenues of bovine translational genomics, and the potential for marker-assisted vaccination

Comprehensive pharmacogenetic profiling of the epidermal growth factor receptor pathway for biomarkers of response to, and toxicity from, cetuximab

Background Somatic mutations in the epidermal growth factor receptor (EGFR) intracellular signalling pathways predict non-response to cetuximab in the treatment of advanced colorectal cancer (aCRC). We hypothesized that common germline variants within these pathways may also play similar roles. Methods We analysed 54 potentially functional, common, inherited EGFR pathway variants in 815 aCRC patients treated with oxaliplatin-fluoropyrimidine chemotherapy +cetuximab. Primary endpoints were response and skin rash (SR). We had >85% power to detect ORs=1.6 for variants with minor allele frequencies >20%. Results We identified five potential biomarkers for response and four for SR, although none remained significant after correction for multiple testing. Our initial data supported a role for Ser313Pro in PIK3R2 in modulating response to cetuximab - in patients with KRAS wild type CRCs, 36.4% of patients with one allele encoding proline responded, as compared to 71.2% of patients homozygous for alleles encoding serine (OR 0.23, 95% CI 0.09-0.56, P=0.0014) and this association was predictive for cetuximab (Pinteraction=0.017); however, independent replication failed to validate this association. No previously proposed predictive biomarkers were validated. Conclusions Our study highlights the need to validate potential pharmacogenetic biomarkers. We did not find strong evidence for common germline biomarkers of cetuximab response and toxicity