510 research outputs found

    Analysis of a char-forming ablator

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    The purpose of this thesis is to conduct an analytical analysis of a char-forming ablation material. This is one phase of ablation heat transfer. Fourier\u27s general equation for one dimensional heat conduction is transformed to moving coordinates and is then solved using the applicable boundary conditions. Solutions of this equation are valid for initial studies in ablation heat transfer --Abstract, page ii

    Effects of Reinforcer Magnitude and d-Amphetamine on Delay Discounting in Rats

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    Delay-discounting procedures are commonly employed to study impulsive choice, which can be defined as choice for a smaller, more immediate reinforcer over a larger, more delayed reinforcer. Differences in reinforcer magnitude have been shown to alter delay discounting with human participants, but results have been mixed with non-human animals. It is also unclear what impact the absolute difference between a smaller, more immediate and a larger, more delayed reinforcer has on choice in a delay-discounting context. Therefore, in Experiment 1 of the present study, effects of different reinforcer magnitudes on delay discounting in rats were examined using a discrete-trials procedure where the absolute, but not relative, difference in smaller, immediate and larger, delayed reinforcers was altered. It was found that rates of delay discounting were lower when choice was between one immediate and three delayed reinforcers (Small-Magnitude Condition), compared to when choice was between two immediate and six delayed reinforcers (Large-Magnitude Condition). d-Amphetamine has been found to alter delay discounting, and baseline levels of delay discounting have been found to be correlated with effects of d-amphetamine on choice. As reinforcer magnitude altered baseline rates of delay discounting in Experiment 1, in Experiment 2, effects of various doses of d-amphetamine (0.1, 0.3, 1.0, and 1.8 mg/kg) on delay discounting were examined in the context arranged in Experiment 1. In general, d-amphetamine decreased delay discounting when rates were relatively high (Small-Magnitude Condition) and increased delay discounting when rates were relatively low (Large-Magnitude Condition), suggesting that baseline rates of delay discounting can influence effects of d-amphetamine on delay discounting

    Characteristics of Cause of Death, Victim, Crime, Offender, and Familial Relationship

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    Broad personality or global traits are unlikely to assist in solving capital crimes, so forensic psychologists have begun to focus on characteristics of the crime to create differentiating profiles. The purpose of this study was to determine if offender and victim characteristics and method of murder could provide cluster profiles differentiating familial relationship between offender and victim. Guided by classical conditioning theory and social learning theory, an archival database of 147 capital offenders responsible for 506 victims was analyzed. Cluster analysis yielded 3 distinct profiles. Compared to other clusters, Cluster 1 offenders tended to be Black and unfamiliar with their victims, who tended to be male between 20 and 50 years old that were typically shot. Cluster 2 offenders tended to be White and familiar with their typically female victims under the age of 20 who they typically murdered by use of blunt force or strangulation. Cluster 3 offenders were distinguished from the other 2 clusters only by having accounted for 90.6% of all victims who were stabbed, but no other associations with variables in the data set were discovered to explain this finding. Though limited in sample size, range of variables, and supplemental insights that could have been gained from case files or interviews, the results contribute to positive social change with offender-victim characteristics and method of murder profiles that begin to differentiate the familial offender-victim relationship and that future research can prospectively build on to create retrospective profiling models, which could potentially lead to resolving unsolved serial murder cases

    Results from the third Scottish National Prevalence Survey: is a population health approach now needed to prevent healthcare-associated infections?

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    Summary Background Healthcare associated infections (HAI) are a major public health concern and a significant cause of morbidity and mortality. A robust and current evidence base that is specific to local, national and Europe-wide settings is necessary to inform the development of strategies to reduce HAI and contain antimicrobial resistance (AMR). Aim To measure the prevalence of HAI and antimicrobial prescribing and identify key priority areas for interventions to reduce the burden of infection. Methods A national rolling PPS in National Health Service (NHS) acute, NHS non-acute, NHS paediatric and independent hospitals was carried out between September and November 2016 using the European Centre for Disease Prevention and Control protocol designed for the European PPS. Findings The prevalence of HAI was 4.6%, 2.7% and 3.2% in acute adults, paediatric and non-acute patient groups, respectively. The most common HAI types reported in adult patients were urinary tract infection and pneumonia. The prevalence of antimicrobial prescribing was 35.7%, 29.3% and 13.8% in acute adults, paediatric and non-acute patient groups, respectively. Respiratory, skin and soft tissue, gastrointestinal and urinary tract infections were the most common infections being treated at the time of survey. Conclusion HAI continues to be a public health concern in Scotland. UTI and pneumonia continue to place a significant burden on patients and on healthcare delivery, including those that develop in the community and require hospital admission. A broader population health approach which focuses on reducing the risk of infection upstream would reduce these infections in both community and hospital settings

    IL-21 receptor expression in human tendinopathy

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    The pathogenetic mechanisms underlying tendinopathy remain unclear, with much debate as to whether inflammation or degradation has the prominent role. Increasing evidence points toward and early inflammatory infiltrate and associated inflammatory cytokine production in human and animal models of tendon disease. The IL-21/IL-21R axis is a proinflammatory cytokine complex that has been associated with chronic inflammatory diseases including rheumatoid arthritis and inflammatory bowel disease. This project aimed to investigate the role and expression of the cytokine/receptor pair IL-21/IL-21R in human tendinopathy. We found significantly elevated expression of IL-21 receptor message and protein in human tendon samples but found no convincing evidence of the presence of IL-21 at message or protein level. The level of expression of IL-21R message/protein in human tenocytes was significantly up regulated by proinflammatory cytokines (TNFα/IL-1β) in vitro. These findings demonstrate that IL-21R is present in early human tendinopathy mainly expressed by tenocytes and macrophages. Despite a lack of IL-21 expression these data again suggest that early tendinopathy has an inflammatory/cytokine phenotype, which may provide novel translational targets in the treatment of tendinopathy

    Morphological effects of porous poly-D,L-lactic acid/hydroxyapatite scaffolds produced by supercritical CO2 foaming on their mechanical performance

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    A novel supercritical CO2 foaming technique was used to fabricate scaffolds of controllable morphology and mechanical properties, with the potential to tailor the scaffolds to specific tissue engineering applications. Biodegradable scaffolds are widely used as temporary supportive structures for bone regeneration. The scaffolds must provide a sufficient mechanical support while allowing cell attachment and growth as well as metabolic activities. In this study, supercritical CO2 foaming was used to prepare fully interconnected porous scaffolds of poly-D,L-lactic acid and poly-D,L-lactic acid/hydroxyapatite. The morphological, mechanical and cell behaviours of the scaffolds were measured to examine the effect of hydroxyapatite on these properties. These scaffolds showed an average porosity in the range of 86%–95%, an average pore diameter of 229–347 µm and an average pore interconnection of 103–207 µm. The measured porosity, pore diameter, and interconnection size are suitable for cancellous bone regeneration. Compressive strength and modulus of up to 36.03 ± 5.90 and 37.97 ± 6.84 MPa were measured for the produced porous scaffolds of various compositions. The mechanical properties presented an improvement with the addition of hydroxyapatite to the structure. The relationship between morphological and mechanical properties was investigated. The matrices with different compositions were seeded with bone cells, and all the matrices showed a high cell viability and biocompatibility. The number of cells attached on the matrices slightly increased with the addition of hydroxyapatite indicating that hydroxyapatite improves the biocompatibility and proliferation of the scaffolds. The produced poly-D,L-lactic acid/hydroxyapatite scaffolds in this study showed a potential to be used as bone graft substitutes

    Distinct neuropeptide-receptor modules regulate a sex-specific behavioral response to a pheromone

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    Dioecious species are a hallmark of the animal kingdom, with opposing sexes responding differently to identical sensory cues. Here, we study the response of C. elegans to the small-molecule pheromone, ascr#8, which elicits opposing behavioral valences in each sex. We identify a novel neuropeptide-neuropeptide receptor (NP/NPR) module that is active in males, but not in hermaphrodites. Using a novel paradigm of neuropeptide rescue that we established, we leverage bacterial expression of individual peptides to rescue the sex-specific response to ascr#8. Concurrent biochemical studies confirmed individual FLP-3 peptides differentially activate two divergent receptors, NPR-10 and FRPR-16. Interestingly, the two of the peptides that rescued behavior in our feeding paradigm are related through a conserved threonine, suggesting that a specific NP/NPR combination sets a male state, driving the correct behavioral valence of the ascr#8 response. Receptor expression within pre-motor neurons reveals novel coordination of male-specific and core locomotory circuitries

    Clinical and Genetic Evaluation of People with or at Risk of Hereditary ATTR Amyloidosis: An Expert Opinion and Consensus on Best Practice in Ireland and the UK

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    Hereditary transthyretin-mediated amyloidosis (hATTR) is challenging to diagnose early owing to the heterogeneity of clinical presentation, which differs according to the TTR gene variant and its penetrance in each individual. The TTR variants seen most frequently in the UK and Ireland (T80A, V142I and V50M) differ to those commonly occurring in other geographic locations and warrant a specific consideration for diagnosis and genetic testing. In addition, recent availability of treatment for this condition has reinforced the need for a more consistent approach to the management of patients, including access to specialist services, genetic testing and counselling, and clinical investigation for families living in the UK and Ireland. A multidisciplinary panel of experts from the UK and Ireland was convened to identify the current challenges, provide recommendations, and develop a consensus for the diagnosis and screening of people with, or at risk of, hATTR. Over a series of meetings, experts shared their current practices and drafted, refined and approved a consensus statement. This consensus statement provides recommendations for three different groups: (1) people with symptoms raising a possibility of hATTR amyloidosis; (2) people with biopsy-confirmed hATTR amyloidosis; and (3) people without symptoms who may have hATTR amyloidosis (i.e. relatives of people with identified TTR variants). For each group, recommendations are made for the required steps for the diagnosis and follow-up of symptomatic patients, and for guidance on the specialist support for counselling and pre-symptomatic genetic testing of at-risk individuals. This guidance is intended to be practical and based on available evidence. The aim is for regional amyloid specialist centres to provide timely diagnosis, clinical screening, and treatment for individuals and their families with hATTR amyloidosis
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