57 research outputs found

    Boundary-layer transition detection by thermography and numerical method around bionic train model in wind tunnel test

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    Methods of diagnosing aerodynamic characteristics are constantly developing in order to conduct the precise and energy efficient wind tunnel testing of transport vehicles in the prototype design early stages. This is of a special importance when facing the time/cost consumption problems of detection of the transition zone over the simplified design of the high-speed train. Herein the applied thermodynamics found a very significant role in the field of experimental aerodynamics. With the intention of detecting the boundary-layer transition zone the following measurements were applied: the infrared thermography, flow visualization, and drag force measurements. In addition, the CFD was applied to predict the flow behaviour and transition zone, solving PDE consisting of the Reynolds-averaged Navier-Stokes equations, energy equation, and the equation of state for an ideal gas employing density-based solver. The thermal imaging defined the transition zone by simple application, and fast recognition, while the transition bounds were defined in the analysis. The flow visualization confirmed thermography results and the method itself as favourable, especially in the most expensive early phases of redesigning for aerodynamically optimized and energy efficient solutions. The numerical method was confirmed by the experiments, resulting in acceptable differences in the definition of the transition zone. For a better understanding of the phenomenon, the overlapped implementation of the presented methods focused on forced convection showed as the best solution. Based on the experiences of this research, development of the additional equipment and adjustments will be introduced in the future experiments

    Evidence Based Development of a Novel Lateral Fibula Plate (VariAx Fibula) Using a Real CT Bone Data Based Optimization Process During Device Development

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    Development of novel implants in orthopaedic trauma surgery is based on limited datasets of cadaver trials or artificial bone models. A method has been developed whereby implants can be constructed in an evidence based method founded on a large anatomic database consisting of more than 2.000 datasets of bones extracted from CT scans. The aim of this study was the development and clinical application of an anatomically pre-contoured plate for the treatment of distal fibular fractures based on the anatomical database

    Imbalance of flight-freeze responses and their cellular correlates in the Nlgn3-/y rat model of autism

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    Abstract Background Mutations in the postsynaptic transmembrane protein neuroligin-3 are highly correlative with autism spectrum disorders (ASDs) and intellectual disabilities (IDs). Fear learning is well studied in models of these disorders, however differences in fear response behaviours are often overlooked. We aim to examine fear behaviour and its cellular underpinnings in a rat model of ASD/ID lacking Nlgn3. Methods This study uses a range of behavioural tests to understand differences in fear response behaviour in Nlgn3 −/y rats. Following this, we examined the physiological underpinnings of this in neurons of the periaqueductal grey (PAG), a midbrain area involved in flight-or-freeze responses. We used whole-cell patch-clamp recordings from ex vivo PAG slices, in addition to in vivo local-field potential recordings and electrical stimulation of the PAG in wildtype and Nlgn3 −/y rats. We analysed behavioural data with two- and three-way ANOVAS and electrophysiological data with generalised linear mixed modelling (GLMM). Results We observed that, unlike the wildtype, Nlgn3 −/y rats are more likely to response with flight rather than freezing in threatening situations. Electrophysiological findings were in agreement with these behavioural outcomes. We found in ex vivo slices from Nlgn3 −/y rats that neurons in dorsal PAG (dPAG) showed intrinsic hyperexcitability compared to wildtype. Similarly, stimulating dPAG in vivo revealed that lower magnitudes sufficed to evoke flight behaviour in Nlgn3 −/y than wildtype rats, indicating the functional impact of the increased cellular excitability. Limitations Our findings do not examine what specific cell type in the PAG is likely responsible for these phenotypes. Furthermore, we have focussed on phenotypes in young adult animals, whilst the human condition associated with NLGN3 mutations appears during the first few years of life. Conclusions We describe altered fear responses in Nlgn3 −/y rats and provide evidence that this is the result of a circuit bias that predisposes flight over freeze responses. Additionally, we demonstrate the first link between PAG dysfunction and ASD/ID. This study provides new insight into potential pathophysiologies leading to anxiety disorders and changes to fear responses in individuals with ASD

    Measurement of Epstein-Barr virus DNA load using a novel quantification standard containing two EBV DNA targets and SYBR Green I dye

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    <p>Abstract</p> <p>Background</p> <p>Reactivation of Epstein-Barr virus (EBV) infection may cause serious, life-threatening complications in immunocompromised individuals. EBV DNA is often detected in EBV-associated disease states, with viral load believed to be a reflection of virus activity. Two separate real-time quantitative polymerase chain reaction (QPCR) assays using SYBR Green I dye and a single quantification standard containing two EBV genes, Epstein-Barr nuclear antigen-1 (EBNA-1) and BamHI fragment H rightward open reading frame-1 (BHRF-1), were developed to detect and measure absolute EBV DNA load in patients with various EBV-associated diseases. EBV DNA loads and viral capsid antigen (VCA) IgG antibody titres were also quantified on a population sample.</p> <p>Results</p> <p>EBV DNA was measurable in ethylenediaminetetraacetic acid (EDTA) whole blood, peripheral blood mononuclear cells (PBMCs), plasma and cerebrospinal fluid (CSF) samples. EBV DNA loads were detectable from 8.0 × 10<sup>2 </sup>to 1.3 × 10<sup>8 </sup>copies/ml in post-transplant lymphoproliferative disease (n = 5), 1.5 × 10<sup>3 </sup>to 2.0 × 10<sup>5 </sup>copies/ml in infectious mononucleosis (n = 7), 7.5 × 10<sup>4 </sup>to 1.1 × 10<sup>5 </sup>copies/ml in EBV-associated haemophagocytic syndrome (n = 1), 2.0 × 10<sup>2 </sup>to 5.6 × 10<sup>3 </sup>copies/ml in HIV-infected patients (n = 12), and 2.0 × 10<sup>2 </sup>to 9.1 × 10<sup>4 </sup>copies/ml in the population sample (n = 218). EBNA-1 and BHRF-1 DNA were detected in 11.0% and 21.6% of the population sample respectively. There was a modest correlation between VCA IgG antibody titre and BHRF-1 DNA load (rho = 0.13, p = 0.05) but not EBNA-1 DNA load (rho = 0.11, p = 0.11).</p> <p>Conclusion</p> <p>Two sensitive and specific real-time PCR assays using SYBR Green I dye and a single quantification standard containing two EBV DNA targets, were developed for the detection and measurement of EBV DNA load in a variety of clinical samples. These assays have application in the investigation of EBV-related illnesses in immunocompromised individuals.</p

    Influence of socioeconomic factors on pregnancy outcome in women with structural heart disease

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    OBJECTIVE: Cardiac disease is the leading cause of indirect maternal mortality. The aim of this study was to analyse to what extent socioeconomic factors influence the outcome of pregnancy in women with heart disease.  METHODS: The Registry of Pregnancy and Cardiac disease is a global prospective registry. For this analysis, countries that enrolled ≥10 patients were included. A combined cardiac endpoint included maternal cardiac death, arrhythmia requiring treatment, heart failure, thromboembolic event, aortic dissection, endocarditis, acute coronary syndrome, hospitalisation for cardiac reason or intervention. Associations between patient characteristics, country characteristics (income inequality expressed as Gini coefficient, health expenditure, schooling, gross domestic product, birth rate and hospital beds) and cardiac endpoints were checked in a three-level model (patient-centre-country).  RESULTS: A total of 30 countries enrolled 2924 patients from 89 centres. At least one endpoint occurred in 645 women (22.1%). Maternal age, New York Heart Association classification and modified WHO risk classification were associated with the combined endpoint and explained 37% of variance in outcome. Gini coefficient and country-specific birth rate explained an additional 4%. There were large differences between the individual countries, but the need for multilevel modelling to account for these differences disappeared after adjustment for patient characteristics, Gini and country-specific birth rate.  CONCLUSION: While there are definite interregional differences in pregnancy outcome in women with cardiac disease, these differences seem to be mainly driven by individual patient characteristics. Adjustment for country characteristics refined the results to a limited extent, but maternal condition seems to be the main determinant of outcome

    Cryptococcus neoformans Intracellular Proliferation and Capsule Size Determines Early Macrophage Control of Infection.

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    Cryptococcus neoformans is a significant fungal pathogen of immunocompromised patients. Many questions remain regarding the function of macrophages in normal clearance of cryptococcal infection and the defects present in uncontrolled cryptococcosis. Two current limitations are: 1) The difficulties in interpreting studies using isolated macrophages in the context of the progression of infection, and 2) The use of high resolution imaging in understanding immune cell behavior during animal infection. Here we describe a high-content imaging method in a zebrafish model of cryptococcosis that permits the detailed analysis of macrophage interactions with C. neoformans during infection. Using this approach we demonstrate that, while macrophages are critical for control of C. neoformans, a failure of macrophage response is not the limiting defect in fatal infections. We find phagocytosis is restrained very early in infection and that increases in cryptococcal number are driven by intracellular proliferation. We show that macrophages preferentially phagocytose cryptococci with smaller polysaccharide capsules and that capsule size is greatly increased over twenty-four hours of infection, a change that is sufficient to severely limit further phagocytosis. Thus, high-content imaging of cryptococcal infection in vivo demonstrates how very early interactions between macrophages and cryptococci are critical in the outcome of cryptococcosis

    How to repair CSK using small perturbation control - Case study and performance analysis

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    In this paper we study coded modulation schemes based on iterated chaotic maps. In particular, we consider CSKCSK-like systems in which a chaotic map is switched depending on the payload. We show how small perturbation control can substantially improve the performance and we demonstrate using a minimum distance approach how absence/wrongly designed control can lead to bad performance

    Minimum distance properties of coded modulations based on iterated chaotic maps

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    In this paper we introduce a method for analyzing the performance of coded modulation schemes based on iterated chaotic maps. In particular, it is known from coding theory that the minimum distance plays an important role, defining the behavior of the error probability performance at sufficiently high signal to noise ratios. We introduce the method and illustrate it for two examples of chaotic maps, the Bernoulli shift map and the tent map. We emphasize that the performance of the map can not be understood by a reasoning in terms of ergodic behavior of the map. The given simulation results confirm the relevance of the minimum distance for describing the performance of such a system

    A Variant of the Kleine-Levin Syndrome following Head Trauma

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    A 19-year-old man developed the Kleine-Levin syndrome three weeks after the head trauma and subsequent neurosurgical evacuation of right-sided, fronto-temporal epidural hematoma. The expression of periodic episodes was observed for hypersomnolence and, to a lesser degree, for behavioral disturbances, while the hyperphagia was constantly present during a period of 1.5 years. These clinical features were associated with the focal, right-sided hypothalamic lesion and ipsilateral posttraumatic parenchymal temporal lobe damage on NMR imaging
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