Segunda neoplasia en cáncer de cabeza y cuello : incidencia y factores de riesgo /

Consultable des del TDXTítol obtingut de la portada digitalitzadaEl objetivo de esta tesis es el de evaluar la hipótesis de que la persistencia de los hábitos tóxicos en los pacientes que han sido diagnosticados y tratados de un carcinoma de cabeza y cuello influye de forma significativa en la posibilidad de aparición de una segunda neoplasia a nivel de las vías aerodigestivas

Neural manifold analysis of brain circuit dynamics in health and disease

Recent developments in experimental neuroscience make it possible to simultaneously record the activity of thousands of neurons. However, the development of analysis approaches for such large-scale neural recordings have been slower than those applicable to single-cell experiments. One approach that has gained recent popularity is neural manifold learning. This approach takes advantage of the fact that often, even though neural datasets may be very high dimensional, the dynamics of neural activity tends to traverse a much lower-dimensional space. The topological structures formed by these low-dimensional neural subspaces are referred to as “neural manifolds”, and may potentially provide insight linking neural circuit dynamics with cognitive function and behavioral performance. In this paper we review a number of linear and non-linear approaches to neural manifold learning, including principal component analysis (PCA), multi-dimensional scaling (MDS), Isomap, locally linear embedding (LLE), Laplacian eigenmaps (LEM), t-SNE, and uniform manifold approximation and projection (UMAP). We outline these methods under a common mathematical nomenclature, and compare their advantages and disadvantages with respect to their use for neural data analysis. We apply them to a number of datasets from published literature, comparing the manifolds that result from their application to hippocampal place cells, motor cortical neurons during a reaching task, and prefrontal cortical neurons during a multi-behavior task. We find that in many circumstances linear algorithms produce similar results to non-linear methods, although in particular cases where the behavioral complexity is greater, non-linear methods tend to find lower-dimensional manifolds, at the possible expense of interpretability. We demonstrate that these methods are applicable to the study of neurological disorders through simulation of a mouse model of Alzheimer’s Disease, and speculate that neural manifold analysis may help us to understand the circuit-level consequences of molecular and cellular neuropathology

QUANTIFICATION OF L-ASCORBIC ACID AND D-ISO-ASCORBIC ACID IN JELLIES FRUIT BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

QUANTIFICATION OF L-ASCORBIC ACID AND D-ISO-ASCORBIC ACID IN JELLIES FRUIT BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY. Ascorbic acid has important nutritional characteristics such as high antioxidant potential, preventing diverse damage and diseases in the tissues and the process of aging. Different isomeric forms of the ascorbic acid can be found in nature and each one have different potential antioxidant and different activity pro-vitamin C. This work examined a method to detect and quantify the isomers L-ascorbic acid (LAA) and D-iso-ascorbic acid (DIAA) in jelly fruit. The method showed acceptable selectivity, linearity, repeatability and recovery. DIAA was not found in the analyzed samples, but LAA was found up to 605 mg in 100 g of sample.3551020102

Bioprospecting of yeasts for amylase production in solid state fermentation and evaluation of the catalytic properties of enzymatic extracts

Profiling microorganisms with potential for amylase production in low cost culture media has been widely recognized due to its broad applicability. The aim of this study was to select yeast strains with potential to produce amylolytic enzymes by solid state fermentation. Fifty-four (54) strains were assessed and three exhibited ability to produce amylases: Candida parapsilosis with 14.68 U/mL (146.8 U/g substrate); Rhodotorula mucilaginosa with 25.0 U/mL (250 U/g substrate), and Candida glabrata with 25.39 U/mL (253.9 U/g substrate), in solid state fermentation, for 120 h at 28°C, using wheat bran with 70% moisture. The enzymes exhibited maximum activity at a pH of 7.0 and at 60°C. Amylases demonstrated satisfactory structural stability, maintaining their catalytic activity after 1 h at 50°C. All enzymes were ethanol tolerant and retained more than 70% of their original activities in 15% ethanol solution. Corn starch was efficiently hydrolyzed by enzymes and the extracts produced by C. parapsilosis and C. glabrata exhibited dextrinizing activity, while those produced by R. mucilaginosa exhibited saccharifying activity. Key words: Candida parapsilosis, Candida glabrata, Rhodotorula mucilaginosa, dextrinizing and saccharifying activit

Revisión del concepto de Pensamiento Crítico en Enfermería: Definición, composición, contextualización y medición

El pensamiento crítico es un proceso cognitivo e intencionado que se aplica para examinar el propio pensamiento e implica reflexionar, efectuar deducciones, conclusiones y toma de decisiones. Además, puede abordarse desde diferentes marcos conceptuales, de ahí la variedad de herramientas y nuevas estrategias dinámicas de aprendizaje existentes para su medición. El objetivo principal de este trabajo, es describir el concepto de pensamiento en base a su definición, sus elementos de composición, su contexto y su medición. La metodología empleada ha sido una revisión bibliográfica sistemática en las bases de datos: CINHAL, PUBMED, PROQUEST, LILLACS, de los términos de estudio: pensamiento crítico, estudiantes de enfermería, competencias, cuidados de enfermería

Separation dichotomy and wavefronts for a nonlinear convolution equation

This paper is concerned with a scalar nonlinear convolution equation which appears naturally in the theory of traveling waves for monostable evolution models. First, we prove that each bounded positive solution of the convolution equation should either be asymptotically separated from zero or it should converge (exponentially) to zero. This dichotomy principle is then used to establish a general theorem guaranteeing the uniform persistence and existence of semi-wavefront solutions to the convolution equation. Finally, we apply our abstract results to several well-studied classes of evolution equations with asymmetric non-local and non-monotone response. We show that, contrary to the symmetric case, these equations can possess at the same time the stationary, the expansion and the extinction waves.Comment: 15 pages, submitte