1,240 research outputs found

    Torque control strategy for an axial flux switched reluctance machine

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    This paper reflects the work done to design a torque control strategy for an axial flux switched reluctance machine. The general electrical model is first presented but as the switched reluctance machine behaves nonlinearly1 a (three-dimensional) finite element method characterization is performed, so the nonlinearity may be considered. Once the machine is characterized in FEM a Simulink model is developed where a torque control strategy is proposed. Then, both the machine and the control are experimentally tested. The control setting, and the obtained real performance results are also presented in this document. Finally, the most outstanding conclusions about the control strategy are captured. Main difficulties encountered during the implementation of the control strategy are also collected

    Plasma cytokines as potential biomarkers of kidney damage in patients with systemic lupus erythematosus

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    Background: Systemic lupus erythematosus is a heterogeneous chronic inflammatory autoimmune disorder characterized by an exacerbated expression of cytokines and chemokines in different tissues and organs. Renal involvement is a significant contributor to the morbidity and mortality of systemic lupus erythematosus, and its diagnosis is based on renal biopsy, an invasive procedure with a high risk of complications. Therefore, the development of alternative, non-invasive diagnostic tests for kidney disease in patients with systemic lupus erythematosus is a priority. Aim: To evaluate the plasma levels of a panel of cytokines and chemokines using multiplex xMAP technology in a cohort of Colombian patients with active and inactive systemic lupus erythematosus, and to evaluate their potential as biomarkers of renal involvement. Results: Plasma from 40 systemic lupus erythematosus non-nephritis patients and 80 lupus nephritis patients with different levels of renal involvement were analyzed for 39 cytokines using Luminex xMAP technology. Lupus nephritis patients had significantly increased plasma eotaxin, TNF-a, interleukin-17-a, interleukin-10, and interleukin-15 as compared to the systemic lupus erythematosus non-nephritis group. Macrophage-derived chemokine, growth regulated oncogene alpha, and epidermal growth factor were significantly elevated in systemic lupus erythematosus non-nephritis patients when compared to lupus nephritis individuals. Plasma eotaxin levels allowed a discrimination between systemic lupus erythematosus non-nephritis and lupus nephritis patients, for which we performed a receiver operating characteristic curve to confirm. We observed a correlation of eotaxin levels with active nephritis (Systemic Lupus Erythematosus Disease Activity Index). Our data indicate that circulating cytokines and chemokines could be considered good predictors of renal involvement in individuals with systemic lupus erythematosus

    Age-dependent changes in insulin-like immunoreactivity in rat submandibular salivary glands.

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    In recent years, a growing interest had arisen in hormonal factors in salivary glands. We have investigated the changes in the content of an insulin-like immunoreactive (ILI) compound in the submandibular salivary glands of Sprague Dawley rats during physiological aging, in the range 15 days-27 months. The amount of ILI in the submandibular glands of young adult rats was found to be doubled in the post-natal period until the age of puberty and was maintained in senescence. No significant correlation was found between age-dependent variations in ILI levels of submandibular salivary glands and circulating insulin concentrations, further supporting previous indications that ILI is being synthesized in situ. It is possible that ILI could exert paracrine effects within the glands, as regards the development of other glandular structures during the first months of life, as well as the preservation of glandular function in senescent animals as well

    Visual population receptive fields in people with schizophrenia have reduced inhibitory surrounds

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    People with schizophrenia (SZ) experience abnormal visual perception on a range of visual tasks, which have been linked to abnormal synaptic transmission and an imbalance between cortical excitation and inhibition. However differences in the underlying architecture of visual cortex neurons, which might explain these visual anomalies, have yet to be reported in vivo. Here, we probe the neural basis of these deficits by using functional MRI (fMRI) and population receptive field (pRF) mapping to infer properties of visually responsive neurons in people with SZ. We employed a Difference-of-Gaussian (DoG) model to capture the centre-surround configuration of the pRF, providing critical information about the spatial scale of the pRFs inhibitory surround. Our analysis reveals that SZ is associated with reduced pRF size in early retinotopic visual cortex as well as a reduction in size and depth of the inhibitory surround in V1, V2 and V4. We consider how reduced inhibition might explain the diverse range of visual deficits reported in SZ. SIGNIFICANCE STATEMENT: People with schizophrenia (SZ) experience abnormal perception on a range of visual tasks, which has been linked to abnormal synaptic transmission and an imbalance between cortical excitation/inhibition. However associated differences in the underlying architecture of visual cortex neurons have yet to be reported in vivo. We used fMRI and population receptive field (pRF) mapping to demonstrate that the fine-grained functional architecture of visual cortex in people with SZ differs from unaffected controls. SZ is associated with reduced pRF size in early retinotopic visual cortex, largely due to reduced inhibitory surrounds. An imbalance between cortical excitation and inhibition could drive such a change in the centre-surround pRF configuration, and ultimately explain the range of visual deficits experienced in SZ

    CONTRIBUCIÓN AL ESTUDIO LIQUENOLÓGICO DE ANDALUCIA OCCIDENTAL, 11. COMUNIDADES SOBRE GRANITOIDES EN LA ZONA MÁS TÉRMICA DE LA PROVINCIA DE SEVILLA

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    Four localities (Gerena, Guillena. Lora del Rio and Almadén de la Plata) from Sevilla district have been studied in detail. The results are presented of 49 relévés which represent the lichen vegetation of these areas. The communities on sunny and exposed to rain surfaces (PurmelieRhizocurpefum tetrasporii), sunny and sheltered surfaces (Acarosporelum epithallinohilaris), shady and variously exposed to rain surfaces (Lusallielum pustulafrie and community of Pertusuria leucosora) and runoff surfaces (Peltuletum euplocae) are given.Se han explorado con detalle cuatro localidades de la provincia de Sevilla (Cierena, Ciuillena, Lora del Río y Almadén de la Plata). De los inventarias levantados en el campo, se transcriben en este trabajo 49 de ellos, por ser los que mejor definen la vegetación liquénica. Se estudian las comunidades de superficie soleadas totalmente abiertas a la lluvia (Parmelio Rhizocarpetumle trasporii), superficies soleadas pero protegidas de la lluvia (Lasallieturn pustulutae y comunidades con Pertusariu leucosora). y por último se estudian las comunidades de supsrficies tle escorrentía (Pelluletum euplocue)

    Global optimization in systems biology: stochastic methods and their applications

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    Mathematical optimization is at the core of many problems in systems biology: (1) as the underlying hypothesis for model development, (2) in model identification, or (3) in the computation of optimal stimulation procedures to synthetically achieve a desired biological behavior. These problems are usually formulated as nonlinear programing problems (NLPs) with dynamic and algebraic constraints. However the nonlinear and highly constrained nature of systems biology models, together with the usually large number of decision variables, can make their solution a daunting task, therefore calling for efficient and robust optimization techniques. Here, we present novel global optimization methods and software tools such as cooperative enhanced scatter search (eSS), AMIGO, or DOTcvpSB, and illustrate their possibilities in the context of modeling including model identification and stimulation design in systems biology.This work was supported by the Spanish MICINN project ”MultiSysBio” (ref. DPI2008-06880-C03-02), and by CSIC intramural project ”BioREDES” (ref. PIE-201170E018).Peer reviewe

    Quantitative evaluation of bias in barcode markers derived from complex samples

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    PCR products have become a major commodity used to identify organisms based on polymorphism at the DNA level. One problem arising is that unbiased identification of organisms takes as working hypothesis that when DNA is extracted from a sample, a positive signal will be obtained if universal primers are used and DNA quality is suitable for PCR. As this assumption is not always correct we used a system where large differences in PCR success have been described to identify where biases appear and maybe identify solutions. Plants can be identified with at least seven independent plastid‐located loci. These differ in their degree of PCR success and how informative they are in terms of taxonomically useful sequence polymorphisms. Here we used six common plastid loci spanning 48 plant species and performed a quantitative analysis of bias at each step of the identification process. As expected we found important differences in PCR efficiency within a single species, depending on the barcoding sequence being amplified. Quantitative PCR revealed that the Ct threshold for various plastid loci, even within a single species, could exhibit greater than 2000‐fold differences in DNA quantity after amplification. We then performed Next Generation Sequencing experiments in nine species using equal quantities of three plastid‐based primers and equally‐mixed quantities of DNA from multiple species. The result was significantly biased towards species and specific loci even when using adaptor‐specific primers. Our results caution that Next‐Generation Sequencing projects may suffer dramatic bias, arising largely during DNA amplification steps. Moreover, that amplification‐based Next Generation Sequencing technologies exhibit additional bias despite using adaptor‐specific primers, indicating that amplification success depends on the DNA fragment. As such, while qualitative analysis of unknown samples are prone to false negative results if a combination of widely‐successful amplicons are not used, quantitative results should be considered highly suspect, even if all species in the starting sample are known.This work was funded by the Comunidad Autónoma de la Región de Murcia Project “Molecular markers in coservation and management of the flora of Murcia Region”

    Short-Cut Method to Assess a Gross Available Energy in a Medium-Load Screw Friction Press

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    The present study proposed a rapid method, based on a previous universal compression tests, to estimate the required load capacity to cold forge different specimen quantity in a screw press. Accordingly, experimental and theoretical approach are performed to check new adjustable drive motor of the modified forging machine to achieve a gross available energy to deform the specimens preventing damage of the forging machine. During the forging experiments, two screw friction presses (as-received and modified) are used to validate the theoretical approach. The modified press exhibits an increase of 51% of gross energy and 11% of maximum load capacity compare to the as-received press. This method is used to improve the effective of the forging process avoiding excessive loads that could promote machine failure. Therefore, a low-cost and easy to implement methodology is proposed to determine the energy and load capacity of a screw friction press to forge different specimen quantities with symmetry pattern configurations.This work is supported by the Ministry of Economy and Competitiveness of Spain (reference project: FJCI-2016-29297), Instituto Nacional de Tecnologia Industrial (INTI) of Argentina and the Aeronautics Advanced Manufacturing Center (CFAA) of Bilbao
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