730 research outputs found

    Insulin-like growth factor II receptors in human brain and their absence in astrogliotic plaques in multiple sclerosis

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    Insulin-like growth factor (IGF) II receptors were studied in human adult brain by using autoradiography with [(125)I]IGF-II. Receptors were found to be widely distributed throughout all neuronal regions. The highest densities were found in plexus choroideus, granular layer of the cerebellar cortex, gyrus dendatus and pyramidal layer of the hippocampus, striatum, and cerebral cortex. White matter was devoid of IGF-II receptors. We also examined [(125)I]IGF-II binding in six plaques of multiple sclerosis, which were characterized by a dense network of astrocytes. Ne were unable to detect IGF-II receptors in any of the astrogliotic plaques, suggesting that IGF-II receptors in human brain are not involved in astrogliosis. The regional variations in neuronal distribution of IGF-II receptors suggest involvement of IGF-II in functions associated with specific neuronal pathways. (C) 2000 Elsevier Science B.V. All rights reserved

    On the multispacecraft determination of periodic surface wave phase speeds and wavelengths

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    Observations of surface waves on the magnetopause indicate a wide range of phase velocities and wavelengths. Their multispacecraft analysis allows a more precise determination of wave characteristics than ever before and reveal shortcomings of approximations to the phase speed that take a predetermined fraction of the magnetosheath speed or the average flow velocity in the boundary layer. We show that time lags between two or more spacecraft can give a qualitative upper estimate, and we confirm the unreliability of flow approximations often used by analyzing a few cases. Using two‐point distant magnetic field observations and spectral analysis of the tailward magnetic field component, we propose an alternative method to estimate the wavelength and phase speed at a single spacecraft from a statistical fit to the data at the other site

    Chronic progressive lymphedema in the Belgian draft horse in Belgium: clinical phenotyping, prevalence and risk factor analysis

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    Chronic progressive lymphedema (CPL) is a well-known problem in the Belgian draft horse. However, tools for clinical diagnosis have not been standardized. Therefore, the exact disease prevalence and the possible CPL risk factors have not been investigated in the Belgian breed yet. The aim of the present study was to assess a uniform CPL clinical examination method to increase diagnostic objectivity as well as to determine the occurrence and severity of lesions. Using univariate and stepwise multivariable logistic regression models, the association of factors, such as age-gender interaction, coat color and season, with CPL occurrence was examined. In this study, it was demonstrated that CPL is highly prevalent in the Belgian draft horse: 60.66% of the horses of the total sample were affected, including a large proportion of young horses (= 3 years). In the latter, the lesions were more explicit as CPL is a chronic disorder. In some horses (i.e. 14% of the yearlings), mild clinical symptoms appeared at approximately the age of one, while distinct onset of the disease occurred from the age of three onwards. The factors age-gender interaction, coat color and season, which are significantly associated with CPL occurrence, were identified and quantified. In this study, a standardized diagnostic protocol is proposed that will enhance future data collection and furthermore will offer a foundation for quantitative genetic research. Ultimately, it will help to reduce CPL occurrence in the Belgian draft horse by means of selection

    Direct visualization of magnetic vortex pinning in superconductors

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    We study the vortex structure in a Pb film deposited on top of a periodic array of ferromagnetic square microrings by combining two high resolution imaging techniques: Bitter decoration and scanning Hall probe microscopy (SHPM). The periodicity and strength of the magnetic pinning potential generated by the square microrings are controlled by the magnetic history of the template. When the square rings are in the magnetized dipolar state, known as the onion state, the strong stray field generated at the domain walls prevents the decoration of vortices. SHPM images show that the stray field generated by the dipoles is much stronger than the vortex field in agreement with the results of simulations. Real space vortex imaging has revealed that, in the onion state, the corners of the square rings act as effective pinning centers for vortices.Comment: To be published in Phys. Rev.

    Implementation of an extended prediction self-adaptive controller using LabVIEW (TM)

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    The implementation of the Extended Prediction Self-Adaptive Controller is presented in this paper. It employs LabVIEWTM graphical programming of industrial equipment and it is suitable for controlling fast processes. Three different systems are used for implementing the control algorithm. The research regarding the controller design using graphical programming demonstrates that a single advanced control application can run on Windows, real time operating systems and FPGA targets without requiring significant program modifications. The most appropriate device may be selected according to the required processing time of the control signal and of the application. A relevant case study is used to exemplify the procedure

    A Portable Implementation on Industrial Devices of a Predictive Controller Using Graphical Programming

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    This paper presents an approach for developing an Extended Prediction Self-Adaptive Controller employing graphical programming of industrial standard devices, for controlling fast processes. For comparison purposes, the algorithm has been implemented on three different FPGA (Field Programmable Gate Arrays) chips. The paper presents research aspects regarding graphical programming controller design, showing that a single advanced control application can run on different targets without requiring significant program modifications. Based on the time needed for processing the control signal and on the application, one can efficiently and easily select the most appropriate device. To exemplify the procedure, a conclusive case study is presented
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