1,599 research outputs found

    An artificial-vision- and statistical-learning-based method for studying the biodegradation of type I collagen scaffolds in bone regeneration systems

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    [Abstract] This work proposes a method based on image analysis and machine and statistical learning to model and estimate osteocyte growth (in type I collagen scaffolds for bone regeneration systems) and the collagen degradation degree due to cellular growth. To achieve these aims, the mass of collagen -subjected to the action of osteocyte growth and differentiation from stem cells- was measured on 3 days during each of 2 months, under conditions simulating a tissue in the human body. In addition, optical microscopy was applied to obtain information about cellular growth, cellular differentiation, and collagen degradation. Our first contribution consists of the application of a supervised classification random forest algorithm to image texture features (the structure tensor and entropy) for estimating the different regions of interest in an image obtained by optical microscopy: the extracellular matrix, collagen, and image background, and nuclei. Then, extracellular-matrix and collagen regions of interest were determined by the extraction of features related to the progression of the cellular growth and collagen degradation (e.g., mean area of objects and the mode of an intensity histogram). Finally, these critical features were statistically modeled depending on time via nonparametric and parametric linear and nonlinear models such as those based on logistic functions. Namely, the parametric logistic mixture models provided a way to identify and model the degradation due to biological activity by estimating the corresponding proportion of mass loss. The relation between osteocyte growth and differentiation from stem cells, on the one hand, and collagen degradation, on the other hand, was determined too and modeled through analysis of image objects’ circularity and area, in addition to collagen mass loss. This set of imaging techniques, machine learning procedures, and statistical tools allowed us to characterize and parameterize type I collagen biodegradation when collagen acts as a scaffold in bone regeneration tasks. Namely, the parametric logistic mixture models provided a way to identify and model the degradation due to biological activity and thus to estimate the corresponding proportion of mass loss. Moreover, the proposed methodology can help to estimate the degradation degree of scaffolds from the information obtained by optical microscopy.Ministerio de Asuntos Económicos y Transformación Digital; MTM2014-52876-RMinisterio de Asuntos Económicos y Transformación Digital; MTM2017-82724-RXunta de Galicia; ED431C-2016-015Xunta de Galicia; ED431G/0

    Analysis of the mechanical properties of wood attacked by Xylotrechus arvicola (Coleoptera: Cerambycidae) larvae, and its influence on the structural properties of the plant

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    Xylotrechus arvicola is an invasive insect on Vitis vinifera in the main wine-producing regions of the Iberian Peninsula. X. arvicola larvae bore into the grapevine wood and make galleries, which cause structural damages to the plant. The aim of this study was to investigate how grapevine wood infested by larvae affects the mechanical properties of the plant in comparation with those of uninfested wood. Samples of grapevine wood uninfested and infested by larvae were collected from vineyards. Compression and flexural strengths as well as simulated structures of grapevine wood in field, in relation to harvest weight by variety, were used to quantify the wood mechanical properties. Infested wood endured a lower strength and normal tension, and exhibited a reduction in the structural capacities in the simulation of harvest weight of 'Cabernet-Sauvignon' variety (up to 62.0 %). 'Tempranillo' (despite its high mechanical slenderness values) and 'Cabernet-Sauvignon', were the varieties that showed a higher resistance on trunks and branches, respectively. A lower bending moment was observed on the infested branches of all varieties. Changes in the mechanical properties of infested wood suggest a decrease in mechanical resistance of wood attacked by larvae that could contribute to the rupture of the infested grapevine over time. Grapevine wood attacked by X. arvicola larvae could be more sensitive to mechanical external factors in vineyards such as strong winds, harvest weight and vibration exerted by harvesting machines

    New models involving quantum chemical parameters for assessing the chromatographic retention process

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    .Knowledge about the theoretical relationship between the analyte properties and the critical chromatographic parameters is mandatory for a better interpretation of the separation mechanism and a more leisurely development of quantitative studies. In a preliminary stage of this work, we introduce the Gumbel distribution, the extreme value distribution type-I widely used in other fields, as a novel tool for modelling the chromatographic peak shape. Further, we develop mathematical models to evaluate the effect of the experimental variables and various quantum parameters on the chromatographic indices, such as the retention time, capacity factor, asymmetry factor, tailing factor and number of theoretical plates. Finally, we propose a mechanistic behaviour for the chromatographic separation process based on the structure-retention relationship of fifteen selected drugs involving several molecular quantum parametersS

    Celdas de combustible microbiano como alternativa para el tratamiento de aguas residuales

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    Las celdas de combustible microbiano (CCM) son una tecnología en desarrollo que constituye una herramienta eficiente para el tratamiento de aguas residuales industriales y urbanas contaminadas, con una simultánea producción de energía. La concentración de los contaminantes se reduce durante el proceso del metabolismo microbiano que genera a la vez electricidad, siendo las CCM consideradas una fuente de energía limpia. En el presente trabajo se realizó una revisión de las CCM, que incluyó los principios de su operación, componentes principales y diseños, los microorganismos comúnmente usados y su clasificación de acuerdo con sus mecanismos característicos de producción de energía y transferencia de electrones. Se analizaron los parámetros aplicados para el tratamiento de diferentes tipos de contaminantes, su eficiencia en la remoción de los mismos, así como la correspondiente producción de energía. En conclusión, se resaltan las ventajas de las CCM como una estrategia eficaz para reducir la contaminación, al ser una herramienta verde alternativa que puede contribuir al desarrollo de nuevos modelos económicos

    An educational environment based on digital image processing to support the learning process of biomaterials degradation in stem cells

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    [Abstract] The Poly(DL-lactide-co-glycolide) copolymers (PDLGA) have designed and performed as biomaterials, taking into account their biodegradability and biocompatibility properties. These materials have a wide range of application in medicine such as orthopedic implants, general surgical implants (suture materials), osteosynthesis, bone cement, among many others. For these reasons, in this paper, we present an intelligent educational environment that can be used for both, researchers and students interested in the analysis of the biomaterial behavior under certain conditions. Our platform includes a Learning Objects (LOs) for MOODLE, and in the same way, implements several digital image processing techniques as well as a decision support module based on a random forest algorithm and statistical modeling. With the aim of determining the real feasibility of this proposal, we have presented the system to 34 Ecuadorian engineering students. After testing the platform, the students answered a survey aimed at determining their perception of the system. The results provide several guidelines to continue with the developing of the platform

    Long-term immune response accompanies clinical outcomes in severe asthmatics treated with anti-IL-5/IL-5R biologics

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    This work was supported by ISCIII - Instituto de Salud Carlos III, FIS (Fondo de Investigación Sanitaria - Spanish Health Research Fund) grants PI21/00896 and FI19/00067; Ciber de Enfermedades Respiratorias (CIBERES); SEAIC grants 22A07; BASEAS STUDY (Basophils in EosinophilicAsthma) Study Code ESR-20-20764 AstraZeneca International; Comunidad de Madrid grant PEJ2021-AI_BMD-22320 and FEDER funds (Fondo Europeo de Desarrollo Regiona

    A chromosome-level genome assembly enables the identification of the follicule stimulating hormone receptor as the master sex determining gene in the flatfish Solea senegalensis

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    Sex determination (SD) shows huge variation among fish and a high evolutionary rate, as illustrated by the Pleuronectiformes (flatfishes). This order is characterized by its adaptation to demersal life, compact genomes and diversity of SD mechanisms. Here, we assembled the Solea senegalensis genome, a flatfish of great commercial value, into 82 contigs (614 Mb) combining long- and short-read sequencing, which were next scaffolded using a highly dense genetic map (28,838 markers, 21 linkage groups), representing 98.9% of the assembly. Further, we established the correspondence between the assembly and the 21 chromosomes by using BAC-FISH. Whole genome resequencing of six males and six females enabled the identification of 41 SNP variants in the follicle stimulating hormone receptor (fshr) consistent with an XX / XY SD system. The observed sex association was validated in a broader independent sample, providing a novel molecular sexing tool. Fshr displayed differential gene expression between male and female gonads from 86 days post-fertilization, when the gonad is still an undifferentiated primordium, concomitant with the activation of amh and cyp19a1a, testis and ovary marker genes, respectively, in males and females. The Y-linked fshr allele, which included 24 non-synonymous variants and showed a highly divergent 3D protein structure, was overexpressed in males compared to the X-linked allele at all stages of gonadal differentiation. We hypothesize a mechanism hampering the action of the follicle stimulating hormone driving the undifferentiated gonad toward testis.info:eu-repo/semantics/acceptedVersio
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