6,866 research outputs found

    Immunopathogenesis of canine chronic ulcerative stomatitis.

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    Canine Chronic Ulcerative Stomatitis is a spontaneously occurring inflammatory disease of the oral mucosa. An immune-mediated pathogenesis is suspected though not yet proven. We have recently reported on the clinical and histologic features, and identification of select leukocyte cell populations within the lesion. A clinical and histologic similarity to oral lichen planus of people was proposed. In the present study, these initial observations are extended by examining lesions from 24 dogs with clinical evidence of chronic ulcerative stomatitis. Because dogs with chronic ulcerative stomatitis often have concurrent periodontal disease, we wondered if dental plaque/biofilm may be a common instigator of inflammation in both lesions. We hypothesized that dogs with chronic ulcerative stomatitis would exhibit a spectrum of pathologic changes and phenotype of infiltrating leukocytes that would inform lesion pathogenesis and that these changes would differ from inflammatory phenotypes in periodontitis. Previously we identified chronic ulcerative stomatitis lesions to be rich in FoxP3+ and IL17+ cells. As such, we suspect that these leukocytes play an important role in lesion pathogenesis. The current study confirms the presence of moderate to large numbers of FoxP3+ T cells and IL17+ cells in all ulcerative stomatitis lesions using confocal immunofluorescence. Interestingly, the majority of IL17+ cells were determined to be non-T cells and IL17+ cell frequencies were negatively correlated with severity on the clinical scoring system. Three histologic subtypes of ulcerative stomatitis were determined; lichenoid, deep stomatitis and granulomatous. Periodontitis lesions, like stomatitis lesions, were B cell and plasma cell rich, but otherwise differed from the stomatitis lesions. Direct immunofluorescence results did not support an autoantibody-mediated autoimmune disease process. This investigation contributes to the body of literature regarding leukocyte involvement in canine idiopathic inflammatory disease pathogenesis

    Little known facts about education: An empirical analysis

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    The thesis consists of four chapters utilising applied micro-econometric techniques to develop a deeper understanding of the education sector. I apply traditional economic concepts such as productivity, immigration, insurance and technological innovation to the field of education economics. Chapter one considers the consequences of academic rank in primary school on later test scores. Using administrative data tracking the student population in England, I estimate the impact of rank on later attainment through the variation in the test-score distributions across schools. The positive impact of rank on attainment helps to explain some puzzles in the education literature, such as the lack of impact of selective schools. The second chapter involves immigration and investigates how the influx of overseas students has affected enrolment of domestic students at UK universities. Using administrative data, I employ methods used in the labour literature to model crowd-out. I find no evidence of crowd-out of domestic students, and some evidence of crowd in amongst postgraduate students. Chapter three establishes the threat of accusations as new source of demand for trade union membership amongst teachers. I model union membership as legal insurance, where demand is determined by the threat of accusations. I measure threat primarily through the incidence of media stories concerning teachers in the local area. Combining these data with union membership data from Labour Force Surveys, I find that unionisation rates increase with media coverage of allegations. The final chapter is an estimation of the impact of restricting technology in the workplace on productivity. This is applied to the education setting using the autonomous decisions by schools to ban mobile phones. Obtaining histories of phone policies through surveys and combining this with administrative data on individual pupil level attainment, I use a difference in difference analysis to estimate the impact on student performance

    Work, stress and play: students’ perceptions of factors impacting on their studies and well‐being

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    Abstract Introduction This study gathered information about life outside of the course for undergraduates studying at the School of Dentistry, Cardiff University. The aim was to explore how these external factors to the course may affect an individual’s academic performance and well‐being. Materials and Methods A cross‐sectional study design was used. An online questionnaire designed for the purpose of the study was used to capture (quantitative and qualitative) data. Questions with dichotomous options, a range of statements with Likert scales (level of agreement) and open (free‐text) questions were used. Data were analysed in SPSS using simple descriptive statistics and frequency distributions. Spearman’s Rho was used to explore relationships for scaled categorical data. Content analysis was used for qualitative data. Results Two‐thirds (n = 69, 63%) of participants reported being very stressed about their studies in the previous 12 months. The majority felt that external factors to their course (e.g. lack of sleep, health issues, financial concerns, hobbies and issues with friends) had impacted on their academic lives with only 9% (n = 10) stating that their lives outside dentistry had no effect. Discussion Those who felt able to pursue hobbies and activities reported a better work‐life balance and less stress. Questions about pursuing hobbies and sleep may help identify students at risk of being stressed or who may benefit from additional support in order to achieve a better work‐life balance. Conclusion This study has highlighted key areas for further investigation and opportunities for improving support to reduce student stress and improve well‐being

    Effects of creatine supplementation on housekeeping genes in human skeletal muscle using real-time RT-PCR.

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    The present study examined the validity and reliability of measuring the expression of various genes in human skeletal muscle using quantitative real-time RT-PCR on a GeneAmp 5700 sequence detection system with SYBR Green 1 chemistry. In addition, the validity of using some of these genes as endogenous controls (i.e., housekeeping genes) when human skeletal muscle was exposed to elevated total creatine levels and exercise was also examined. For all except 28S, linear relationships between the logarithm of the starting RNA concentrations and the cycle threshold (C(T)) values were established for beta-actin, beta2-microglobulin (beta2M), cyclophilin (CYC), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). We found a linear response between C(T) values and the logarithm of a given amount of starting cDNA for all the genes tested. The overall intra-assay coefficient of variance for these genes was 1.3% and 21% for raw C(T) values and the linear value of 2(-C(T)), respectively. Interassay variability was 2.3% for raw C(T) values and 34% for the linear value of 2(-C(T)). We also examined the expression of various housekeeping genes in human skeletal muscle at days 0, 1, and 5 following oral supplementation with either creatine or a placebo employing a double-blind crossover study design. Treatments were separated by a 5-wk washout period. Immediately following each muscle sampling, subjects performed two 30-s all-out bouts on a cycle ergometer. Creatine supplementation increased (P < 0.05) muscle total creatine content above placebo levels; however, there were no changes (P > 0.05) in C(T) values across the supplementation periods for any of the genes. Nevertheless, 95% confidence intervals showed that GAPDH was variable, whereas beta-actin, beta2M, and CYC were the least varying genes. Normalization of the data to these housekeeping genes revealed variable behavior for beta2M with more stable expressions for both beta-actin and CYC. We conclude that, using real-time RT-PCR, beta-actin or CYC may be used as housekeeping genes to study gene expression in human muscle in experiments employing short-term creatine supplementation combined with high-intensity exercise

    Atomic transition frequencies, isotope shifts, and sensitivity to variation of the fine structure constant for studies of quasar absorption spectra

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    Theories unifying gravity with other interactions suggest spatial and temporal variation of fundamental "constants" in the Universe. A change in the fine structure constant, alpha, could be detected via shifts in the frequencies of atomic transitions in quasar absorption systems. Recent studies using 140 absorption systems from the Keck telescope and 153 from the Very Large Telescope, suggest that alpha varies spatially. That is, in one direction on the sky alpha seems to have been smaller at the time of absorption, while in the opposite direction it seems to have been larger. To continue this study we need accurate laboratory measurements of atomic transition frequencies. The aim of this paper is to provide a compilation of transitions of importance to the search for alpha variation. They are E1 transitions to the ground state in several different atoms and ions, with wavelengths ranging from around 900 - 6000 A, and require an accuracy of better than 10^{-4} A. We discuss isotope shift measurements that are needed in order to resolve systematic effects in the study. The coefficients of sensitivity to alpha-variation (q) are also presented.Comment: Includes updated version of the "alpha line" lis

    Pseudorehearsal in value function approximation

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    Catastrophic forgetting is of special importance in reinforcement learning, as the data distribution is generally non-stationary over time. We study and compare several pseudorehearsal approaches for Q-learning with function approximation in a pole balancing task. We have found that pseudorehearsal seems to assist learning even in such very simple problems, given proper initialization of the rehearsal parameters

    Changes in microphytobenthos fluorescence over a tidal cycle: implications for sampling designs

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    Intertidal microphytobenthos (MPB) are important primary producers and provide food for herbivores in soft sediments and on rocky shores. Methods of measuring MPB biomass that do not depend on the time of collection relative to the time of day or tidal conditions are important in any studies that need to compare temporal or spatial variation, effects of abiotic factors or activity of grazers. Pulse amplitude modulated (PAM) fluorometry is often used to estimate biomass of MPB because it is a rapid, non-destructive method, but it is not known how measures of fluorescence are altered by changing conditions during a period of low tide. We investigated this experimentally using in situ changes in minimal fluorescence (F) on a rocky shore and on an estuarine mudflat around Sydney (Australia), during low tides. On rocky shores, the time when samples are taken during low tide had little direct influence on measures of fluorescence as long as the substratum is dry. Wetness from wave-splash, seepage from rock pools, run-off, rainfall, etc., had large consequences for any comparisons. On soft sediments, fluorescence was decreased if the sediment dried out, as happens during low-spring tides on particularly hot and dry days. Surface water affected the response of PAM and therefore measurements used to estimate MPB, emphasising the need for care to ensure that representative sampling is done during low tide

    Bioethanol from poplar clone Imola: an environmentally viable alternative to fossil fuel?

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    BACKGROUND: Environmental issues, e.g. climate change, fossil resource depletion have triggered ambitious national/regional policies to develop biofuel and bioenergy roles within the overall energy portfolio to achieve decarbonising the global economy and increase energy security. With the 10 % binding target for the transport sector, the Renewable Energy Directive confirms the EU’s commitment to renewable transport fuels especially advanced biofuels. Imola is an elite poplar clone crossed from Populus deltoides Bartr. and Populus nigra L. by Research Units for Intensive Wood Production, Agriculture Research Council in Italy. This study examines its suitability for plantation cultivation under short or very short rotation coppice regimes as a potential lignocellulosic feedstock for the production of ethanol as a transport biofuel. A life cycle assessment (LCA) approach was used to model the cradle-to-gate environmental profile of Imola-derived biofuel benchmarked against conventional fossil gasoline. Specific attention was given to analysing the agroecosystem fluxes of carbon and nitrogen occurring in the cultivation of the Imola biomass in the biofuel life cycle using a process-oriented biogeochemistry model (DeNitrification-DeComposition) specifically modified for application to 2G perennial bioenergy crops and carbon and nitrogen cycling. RESULTS: Our results demonstrate that carbon and nitrogen cycling in perennial crop–soil ecosystems such as this example can be expected to have significant effects on the overall environmental profiles of 2G biofuels. In particular, soil carbon accumulation in perennial biomass plantations is likely to be a significant component in the overall greenhouse gas balance of future biofuel and other biorefinery products and warrants ongoing research and data collection for LCA models. We conclude that bioethanol produced from Imola represents a promising alternative transport fuel offering some savings ranging from 35 to 100 % over petrol in global warming potential, ozone depletion and photochemical oxidation impact categories. CONCLUSIONS: Via comparative analyses for Imola-derived bioethanol across potential supply chains, we highlight priority issues for potential improvement in 2G biofuel profiling. Advanced clones of poplar such as Imola for 2G biofuel production in Italy as modelled here show potential to deliver an environmentally sustainable lignocellulosic biorefinery industry and accelerate advanced biofuel penetration in the transport sector. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13068-015-0318-8) contains supplementary material, which is available to authorized users

    Risk factors for presentation to hospital with severe anaemia in Tanzanian children: a case-control study.

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    In malaria endemic areas anaemia is a usually silent condition that nevertheless places a considerable burden on health services. Cases of severe anaemia often require hospitalization and blood transfusions. The objective of this study was to assess risk factors for admission with anaemia to facilitate the design of anaemia control programmes. We conducted a prospective case-control study of children aged 2-59 months admitted to a district hospital in southern Tanzania. There were 216 cases of severe anaemia [packed cell volume (PCV) < 25%] and 234 age-matched controls (PCV > or = 25%). Most cases [55.6% (n = 120)] were < 1 year of age. Anaemia was significantly associated with the educational level of parents, type of accommodation, health-seeking behaviour, the child's nutritional status and recent and current medical history. Of these, the single most important factor was Plasmodium falciparum parasitaemia [OR 4.3, 95% confidence interval (CI) 2.9-6.5, P < 0.001]. Multivariate analysis showed that increased recent health expenditure [OR 2.2 (95% CI 1.3-3.9), P = 0.005], malnutrition [OR 2.4 (95%CI 1.3-4.3), P < 0.001], living > 10 km from the hospital [OR 3.0 (95% CI 1.9-4.9), P < 0.001], a history of previous blood transfusion [OR 3.8 (95% CI 1.7-9.1), P < 0.001] and P. falciparum parasitaemia [OR 9.5 (95% CI 4.3-21.3), P < 0.001] were independently related to risk of being admitted with anaemia. These findings are considered in terms of the pathophysiological pathway leading to anaemia. The concentration of anaemia in infants and problems of access to health services and adequate case management underline the need for targeted preventive strategies for anaemia control
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