Person: Chevalier Del Río, Margarita
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First Name
Margarita
Last Name
Chevalier Del Río
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Medicina
Department
Radiología, Rehabilitación y Fisioterapia
Area
Radiología y Medicina Física
Identifiers
18 results
Search Results
Now showing 1 - 10 of 18
Item Theoretical approach to hyperacuity tests based on resolution criteria for two-line images(Proceedings of Holography, Interferometry, and Optical Pattern Recognition in Biomedicine, 1991) Mondal, Pronab Kumar; Calvo Padilla, María Luisa; Lakshminarayanan, Vasudevan; Chevalier Del Río, MargaritaResolution criteria for resolving two line images under coherent and incoherent illumination are presented. This technique has been used to interpret psychophysical data obtained from hyperacuity paradigms.Item Edge image processing: An analysis of modified heaviside functions as degraded edge generators(17th Congress of the International Commission for Optics: Optics For Science And New Technology, Pts 1 And 2, 1996) Manzanares Ituarte, Ana; Calvo Padilla, María Luisa; Chevalier Del Río, Margarita; Lakshminarayanan, VasudevanItem Line spread function formulation proposed by W. H. Steel: A revision(Applied Optics, 1997) Manzanares Ituarte, Ana; Calvo Padilla, María Luisa; Chevalier Del Río, Margarita; Lakshminarayanan, VasudevanA revised formulation of the image Light distribution of an incoherent line source proposed by Steel [Rev. Opt. 31, 334-340 (1952)] is presented. Analytical and numerical results based on this new representation are given. We explicitly show that a major error in Steel's final expression generates singularities, thereby preventing convenient numerical computation.Item Sampled hard edge reconstruction: Definition of frequency modulation function for a sampling-reconstructing system (not quantized)(17th Congress of the International Commission for Optics: Optics for Science and New Technology, Pts 1 and 2, 1996) Sanz, Inmaculada; Calvo Padilla, María Luisa; Chevalier Del Río, MargaritaItem Applications Of Optical Image Processing For The Determination Of The Optical Properties Of The Cellular Membranes.(10th International Optical Computing Conference, 1984) Carreras Béjar, Carmen; Chevalier Del Río, Margarita; Calvo Padilla, María LuisaIn this paper, we present a theoretical model for the transmission function of a biological cell. Three different cases have been considered: a) Real transmission function, b) Pure phase Object, c) Mixed case where both, real and complex terms are present in the transmission function. We have studied in all those cases the response in the Fourier plane. The comparison of the models proposed above allow us to conclude that the most correct treatment would come from c). Even if the cytoplasm gives the most important contribution, neither the nucleus nor the membrane can be neglected.Item Item Optical image processing to determine the optical properties of cellular membranes(Applied Optics, 1984) Carreras Béjar, Carmen; Chevalier Del Río, Margarita; Calvo Padilla, María LuisaIn this paper we present a theoretical model for the transmission function of a biological cell. Three different cases are considered: real transmission function, pure phase object, general case, where both real and complex terms are present in the transmission function. In all cases we studied the response in the Fourier plane. Comparison of the proposed models leads us to conclude that the most correct treatment would come from the general case, where it was found that the membrane contribution predominates in the total diffracted amplitude distribution.Item Resistance to Degradation of Silk Fibroin Hydrogels Exposed to Neuroinflammatory Environments(Polymers, 2023) Yonesi, Mahdi; Ramos, Milagros; Ramírez Castillejo, Carmen; Fernández Serra, Rocío; González Nieto, Daniel; Panetsos Petrova, Fivos; Belarra, Adrián; Chevalier Del Río, Margarita; Rojo, Francisco J.; Pérez Rigueiro, José; Guinea, Gustavo V.Central nervous system (CNS) diseases represent an extreme burden with significant social and economic costs. A common link in most brain pathologies is the appearance of inflammatory components that can jeopardize the stability of the implanted biomaterials and the effectiveness of therapies. Different silk fibroin scaffolds have been used in applications related to CNS disorders. Although some studies have analyzed the degradability of silk fibroin in non-cerebral tissues (almost exclusively upon non-inflammatory conditions), the stability of silk hydrogel scaffolds in the inflammatory nervous system has not been studied in depth. In this study, the stability of silk fibroin hydrogels exposed to different neuroinflammatory contexts has been explored using an in vitro microglial cell culture and two in vivo pathological models of cerebral stroke and Alzheimer’s disease. This biomaterial was relatively stable and did not show signs of extensive degradation across time after implantation and during two weeks of in vivo analysis. This finding contrasted with the rapid degradation observed under the same in vivo conditions for other natural materials such as collagen. Our results support the suitability of silk fibroin hydrogels for intracerebral applications and highlight the potentiality of this vehicle for the release of molecules and cells for acute and chronic treatments in cerebral pathologies. © 2023 by the authors.Item Edge image quality assessment: a new formulation for degraded edge imaging(Image and Vision omputing, 1998) Manzanares Ituarte, Ana; Calvo Padilla, María Luisa; Chevalier Del Río, Margarita; Lakshminarayanan, VasudevanWe discuss a formalism to characterize degraded edge images formed in a diffraction limited system (with circular pupil of unit radius) under conditions of incoherent illumination. We introduce a novel definition of degraded edges and consider this approach to model a basic optical mechanism involved in the perception of visual depth and edge detection. We introduce a degradation parameter to quantize the degree of edge blur. We present a generalization of such a procedure by assuming the Heaviside function to be a systematic generator of degraded edges. We reproduce experimentally the predictions made by the formalism proposed herein.- Project number: 184
Item Desarrollo de una herramienta para la evaluación de los examen tipo test y sus aplicaciones en la mejora de la calidad y en los criterios de evaluación de estos exámenes(2018) García Pinto, Diego; Guibelalde Del Castillo, Eduardo; Turrero Nogués, Agustín; Castillo Garcia, Maria; Garcia Salinero, Antonia; Prieto Renieblas, Gabriel; Delgado Martínez, Víctor; Vaño Carruana, Eliseo; Fernández Soto, José Miguel; Prieto Martín, Carlos; López Fernández, Alfonso; Chevalier Del Río, Margarita