763 research outputs found

    Erosion—diagnosis and risk factors

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    Dental erosion is a multifactorial condition: The interplay of chemical, biological and behavioural factors is crucial and helps explain why some individuals exhibit more erosion than others. The erosive potential of erosive agents like acidic drinks or foodstuffs depends on chemical factors, e.g. pH, titratable acidity, mineral content, clearance on tooth surface and on its calcium-chelation properties. Biological factors such as saliva, acquired pellicle, tooth structure and positioning in relation to soft tissues and tongue are related to the pathogenesis of dental erosion. Furthermore, behavioural factors like eating and drinking habits, regular exercise with dehydration and decrease of salivary flow, excessive oral hygiene and, on the other side, an unhealthy lifestyle, e.g. chronic alcoholism, are predisposing factors for dental erosion. There is some evidence that dental erosion is growing steadily. To prevent further progression, it is important to detect this condition as early as possible. Dentists have to know the clinical appearance and possible signs of progression of erosive lesions and their causes such that adequate preventive and, if necessary, therapeutic measures can be initiated. The clinical examination has to be done systematically, and a comprehensive case history should be undertaken such that all risk factors will be reveale

    Erosion—diagnosis and risk factors

    Get PDF
    Dental erosion is a multifactorial condition: The interplay of chemical, biological and behavioural factors is crucial and helps explain why some individuals exhibit more erosion than others. The erosive potential of erosive agents like acidic drinks or foodstuffs depends on chemical factors, e.g. pH, titratable acidity, mineral content, clearance on tooth surface and on its calcium-chelation properties. Biological factors such as saliva, acquired pellicle, tooth structure and positioning in relation to soft tissues and tongue are related to the pathogenesis of dental erosion. Furthermore, behavioural factors like eating and drinking habits, regular exercise with dehydration and decrease of salivary flow, excessive oral hygiene and, on the other side, an unhealthy lifestyle, e.g. chronic alcoholism, are predisposing factors for dental erosion. There is some evidence that dental erosion is growing steadily. To prevent further progression, it is important to detect this condition as early as possible. Dentists have to know the clinical appearance and possible signs of progression of erosive lesions and their causes such that adequate preventive and, if necessary, therapeutic measures can be initiated. The clinical examination has to be done systematically, and a comprehensive case history should be undertaken such that all risk factors will be revealed

    Insight into High-quality Aerodynamic Design Spaces through Multi-objective Optimization

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    An approach to support the computational aerodynamic design process is presented and demonstrated through the application of a novel multi-objective variant of the Tabu Search optimization algorithm for continuous problems to the aerodynamic design optimization of turbomachinery blades. The aim is to improve the performance of a specific stage and ultimately of the whole engine. The integrated system developed for this purpose is described. This combines the optimizer with an existing geometry parameterization scheme and a well- established CFD package. The system’s performance is illustrated through case studies – one two-dimensional, one three-dimensional – in which flow characteristics important to the overall performance of turbomachinery blades are optimized. By showing the designer the trade-off surfaces between the competing objectives, this approach provides considerable insight into the design space under consideration and presents the designer with a range of different Pareto-optimal designs for further consideration. Special emphasis is given to the dimensionality in objective function space of the optimization problem, which seeks designs that perform well for a range of flow performance metrics. The resulting compressor blades achieve their high performance by exploiting complicated physical mechanisms successfully identified through the design process. The system can readily be run on parallel computers, substantially reducing wall-clock run times – a significant benefit when tackling computationally demanding design problems. Overall optimal performance is offered by compromise designs on the Pareto trade-off surface revealed through a true multi-objective design optimization test case. Bearing in mind the continuing rapid advances in computing power and the benefits discussed, this approach brings the adoption of such techniques in real-world engineering design practice a ste

    Increase of Fungal Endocarditis in Children

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    Background:: Infective endocarditis (IE) is a rare and feared infection that mainly occurs in patients with underlying cardiac disease or altered function of the immune system. Recent epidemiological data on both sepsis and nosocomial infections indicate a rise in gram-negative bacterial and fungal infection, particularly in patients requiring critical care support. This study sought to characterize the change in the spectrum of IE encountered in a single pediatric tertiary care center during the last 18 years, to evaluate emergence of fungal IE and to identify contributing factors. Patients and Methods:: Review of all cases of IE diagnosed between January 1986 and August 2003 at a single university children's hospital. Patients were distributed between two equal time periods and compared according to the era of IE diagnosis. Results:: In 43 patients, 44 episodes of IE were identified with most cases occurring in children with congenital or acquired heart disease. The annual number of diagnosed cases fluctuated during the study (mean 2.4 cases/year). Blood or specimen cultures were positive in 34 cases (77%) with gram-positive organisms most frequently observed (n = 20, 44.4%). Fungal IE cases (n = 9, 20%) occurred preferentially during the second period (p < 0.03), and were more common in children with noncardiac diseases (p = 0.023). Factors associated with fungal IE were the use of broad-spectrum antibiotics (p < 0.001) and the presence of an infected central venous catheter (p = 0.01). Overall mortality did not differ between the two eras. Conclusion:: The incidence of fungal IE seems to have significantly increased in more recent years. Use of broadspectrum antibiotics for prolonged time or/and central venous catheters were identified as predisposing factors to fungal infective endocarditi

    Dominance or tolerance? Causes and consequences of a period of increased intercommunity encounters among bonobos (Pan paniscus) at LuiKotale

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    Group-living primates exhibit variable reactions to intergroup encounters (or IGEs), reflecting species-specific strategies and individual motivations. In chimpanzees (Pan troglodytes), dominating in IGEs provides fitness benefits. Less is known about responses to IGEs in bonobos (Pan paniscus) despite their equal relevance for understanding the origins of human intergroup relations. We observed the Bompusa West (WBp) bonobo community at LuiKotale during a 2-month shift in ranging resulting in frequent IGEs with the smaller Bompusa East (EBp) community. We tested whether incursions provided ecological benefits, and whether responses to IGEs were consistent with inter-community dominance or tolerance. We measured fruit availability and collected activity scans from 26 mature WBp community members when in their core ranging area, during incursions into the EBp ranging area, and during IGEs. We collected data on sexual interactions and aggression with in-group and out-group members during 19 independent IGEs. During their shift in ranging, fruit availability was greater in the EBp ranging area, and WBp bonobos consumed more fruit during incursions than when in their core ranging area. Coalitionary intergroup aggression occurred during nine IGEs, and outcomes were consistent with imbalances in fighting power, in that larger WBp parties supplanted smaller EBp parties from the immediate area. However, communities reformed associations following 70% of coalitionary conflicts, and prolonged IGEs facilitated out-group sexual interactions and female transfers. The WBp community shift in ranging was likely motivated by ecological factors and responses to increased IGEs reflected a mixture of competitive and tolerant strategies

    Impact of Prenatal Stress on Offspring Glucocorticoid Levels: A Phylogenetic Meta-analysis Across 14 Vertebrate Species

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    Prenatal exposure to maternal stress is commonly associated with variation in Hypothalamic Pituitary Adrenal (HPA)-axis functioning in ofspring. However, the strength or consistency of this response has never been empirically evaluated across vertebrate species. Here we meta-analyzed 114 results from 39 studies across 14 vertebrate species using Bayesian phylogenetic mixed-efects models. We found a positive overall efect of prenatal stress on ofspring glucocorticoids (d’=0.43) though the 95% Highest Posterior Density Interval overlapped with 0 (−0.16–0.95). Meta-regressions of potential moderators highlighted that phylogeny and life history variables predicted relatively little variation in efect size. Experimental studies (d’=0.64) produced stronger efects than observational ones (d’=−0.01), while prenatal stress afected glucocorticoid recovery following ofspring stress exposure more strongly (d’=0.75) than baseline levels (d’=0.48) or glucocorticoid peak response (d’=0.36). These fndings are consistent with the argument that HPA-axis sensitivity to prenatal stress is evolutionarily ancient and occurs regardless of a species’ overall life history strategy. These efects may therefore be especially important for mediating intra-specifc life-history variation. In addition, these fndings suggest that animal models of prenatal HPA-axis programming may be appropriate for studying similar efects in humans

    High-throughput and high-precision laser micromachining with ps-pulses in synchronized mode with a fast polygon line scanner

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    To be competitive in laser micro machining, high throughput is an important aspect. One possibility to increase productivity is scaling up the ablation process i.e. linearly increasing the laser repetition rate together with the average power and the scan speed. In the MHz-regime high scan speeds are required which cannot be provided by commercially available galvo scanners. In this work we will report on the results by using a polygon line scanner having a maximum scan speed of 100 m/s and a 50 W ps-laser system, synchronized via the SuperSync™ technology. We will show the results concerning the removal rate and the surface quality for working at the optimum point i.e. most efficient point at repetition rates up to 8.2 MHz

    Predicting Fluid Intelligence of Children using T1-weighted MR Images and a StackNet

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    In this work, we utilize T1-weighted MR images and StackNet to predict fluid intelligence in adolescents. Our framework includes feature extraction, feature normalization, feature denoising, feature selection, training a StackNet, and predicting fluid intelligence. The extracted feature is the distribution of different brain tissues in different brain parcellation regions. The proposed StackNet consists of three layers and 11 models. Each layer uses the predictions from all previous layers including the input layer. The proposed StackNet is tested on a public benchmark Adolescent Brain Cognitive Development Neurocognitive Prediction Challenge 2019 and achieves a mean squared error of 82.42 on the combined training and validation set with 10-fold cross-validation. In addition, the proposed StackNet also achieves a mean squared error of 94.25 on the testing data. The source code is available on GitHub.Comment: 8 pages, 2 figures, 3 tables, Accepted by MICCAI ABCD-NP Challenge 2019; Added ND

    Prosociality, social tolerance and partner choice facilitate mutually beneficial cooperation in common marmosets, Callithrix jacchus

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    Prosocial motivation has been suggested to facilitate the initiation and maintenance of cooperative interactions, as well as the evolution of social systems reliant on helping behaviour and social coordination. Previous comparative research on the link between prosociality and cooperation has been limited, however, by the absence of directly comparable measures of these traits among the same individuals. In the present study, we therefore examined intraspecific variation in prosociality and cooperative behaviour within a captive colony of group-living, cooperatively breeding common marmosets to provide a direct experimental test of these hypothesized benefits. We measured prosociality using a group service food-provisioning paradigm, and we assessed mutually beneficial dyadic cooperation with the loose string coordinated pulling paradigm. In addition, we also investigated the effects of individual social tolerance and partner choice, which have previously been identified as key factors promoting prosociality and cooperation among primates. As predicted, successful cooperation in the loose string paradigm was positively associated with prosociality, as well as with social tolerance and partner choice. These effects were independent of age, sex, personality, food motivation and learning across experimental sessions. Our results therefore suggest that prosocial motivation, social tolerance and partner choice can each facilitate mutually beneficial cooperation and social coordination in marmosets, supporting the hypothesized role of these mechanisms in the evolution of cooperative behaviour among primates
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