Segmentation of bone structures in 3D CT images based on continuous max- ow optimization

In this paper an algorithm to carry out the automatic segmentation of bone structures in 3D CT images has been implemented. Automatic segmentation of bone structures is of special interest for radiologists and surgeons to analyze bone diseases or to plan some surgical interventions. This task is very complicated as bones usually present intensities overlapping with those of surrounding tissues. This overlapping is mainly due to the composition of bones and to the presence of some diseases such as Osteoarthritis, Osteoporosis, etc. Moreover, segmentation of bone structures is a very time-consuming task due to the 3D essence of the bones. Usually, this segmentation is implemented manually or with algorithms using simple techniques such as thresholding and thus providing bad results. In this paper gray information and 3D statistical information have been combined to be used as input to a continuous max- ow algorithm. Twenty CT images have been tested and di erent coe cients have been computed to assess the performance of our implementation. Dice and Sensitivity values above 0.91 and 0.97 respectively were obtained. A comparison with Level Sets and thresholding techniques has been carried out and our results outperformed them in terms of accuracy.Ministerio de ciencia e innovación TEC2010-21619-C04-02Junta de Andalucía P11-TIC-772

Constructores de la naturaleza. Sus técnicas

[ES] En este trabajo se demuestra la capacidad de algunos animales, no especialmente complejos, de crear sofisticadas construcciones con desarrollo tecnológico notable. Se ofrece, por tanto, un amplio abanico de las técnicas que son comúnmente utilizadas para modificar su entorno, creando nuevos ambientes, y adecuarlo a sus necesidades más básicas. De este modo, es imprescindible estudiar previamente el funcionamiento del comportamiento animal y cuales son los criterios más influyentes en el desarrollo de la construcción de sus propios habitáculos. Además, se evidencia que sin duda el ser humano ha obtenido de los animales las distintas técnicas, para aplicarlas después a usos diversos y desarrollarlas hasta alcanzar una gran eficiencia y complejidad, ofreciendo una visión crítica de la aplicación de sus técnicas a nuestras construcciones[EN] This work demonstrates the capacity of some animals, not very complex, to create sophisticated constructions with remarkable technology. It offers, therefore, a wide range of techniques that are used to modify their environment, creating new environments, and adapt it to their most basic needs. In this way, it is essential to study previously the behavior of animals and what are the most influential criteria in the development of the construction of their own living spaces. In addition, it was evidenced that, without a doubt, the human being has obtained the results of the animals, the posterior techniques to multiple uses and advanced to the latest technology, a critical vision of the application of the techniques to our constructions.Pérez Piñero, CM. (2019). Constructores de la naturaleza. Sus técnicas. http://hdl.handle.net/10251/120069TFG

Decreased Perifoveal Sensitivity Detected by Microperimetry in Patients Using Hydroxychloroquine and without Visual Field and Fundoscopic Anomalies

Purpose. To evaluate the usefulness of microperimetry in the early detection of the ocular anomalies associated with the use of hydroxychloroquine. Methods. Prospective comparative case series study comprising 14 healthy eyes of 7 patients (group A) and 14 eyes of 7 patients under treatment with hydroxychloroquine for the treatment of rheumatologic diseases and without fundoscopic or perimetric anomalies (group B). A comprehensive ophthalmological examination including microperimetry (MP) and spectraldomain optical coherence tomography was performed in both groups. Results. No significant differences were found in mean MP foveal sensitivity between groups (P = 0.18). However, mean MP overall sensitivity was significantly higher in group A (29.05 ± 0.57 dB versus group B, 26.05 ± 2.75 dB; P < 0.001). Significantly higher sensitivity values were obtained in group A in comparison to group B for the three eccentric loci evaluated (P < 0.001). Conclusion. Microperimetry seems to be a useful tool for the early detection of retinal damage in patients treated with hydroxychloroquine

Lente de contacto híbrida de geometría inversa en córnea irregular con presencia de isla central tras cirugía LASIK

La lente híbrida de geometría inversa PS ofrece una mejoría de la calidad visual en pacientes con córneas irregulares tras cirugía refractiva miópica, mostrándose como una excelente opción en aquellos casos en que el insuficiente lecho corneal imposibilita retratamientos posteriores

Error induced by the estimation of the corneal power and the effective lens position with a rotationally asymmetric refractive multifocal intraocular lens

AIM: To evaluate the prediction error in intraocular lens (IOL) power calculation for a rotationally asymmetric refractive multifocal IOL and the impact on this error of the optimization of the keratometric estimation of the corneal power and the prediction of the effective lens position (ELP). METHODS: Retrospective study including a total of 25 eyes of 13 patients (age, 50 to 83y) with previous cataract surgery with implantation of the Lentis Mplus LS-312 IOL (Oculentis GmbH, Germany). In all cases, an adjusted IOL power (PIOLadj) was calculated based on Gaussian optics using a variable keratometric index value (nkadj) for the estimation of the corneal power (Pkadj) and on a new value for ELP (ELPadj) obtained by multiple regression analysis. This PIOLadj was compared with the IOL power implanted (PIOLReal) and the value proposed by three conventional formulas (Haigis, Hoffer Q and Holladay). RESULTS: PIOLReal was not significantly different than PIOLadj and Holladay IOL power (P>0.05). In the Bland and Altman analysis, PIOLadj showed lower mean difference (-0.07 D) and limits of agreement (of 1.47 and -1.61 D) when compared to PIOLReal than the IOL power value obtained with the Holladay formula. Furthermore, ELPadj was significantly lower than ELP calculated with other conventional formulas (P<0.01) and was found to be dependent on axial length, anterior chamber depth and Pkadj. CONCLUSION: Refractive outcomes after cataract surgery with implantation of the multifocal IOL Lentis Mplus LS-312 can be optimized by minimizing the keratometric error and by estimating ELP using a mathematical expression dependent on anatomical factors

Positional accommodative intraocular lens power error induced by the estimation of the corneal power and the effective lens position

Purpose: To evaluate the predictability of the refractive correction achieved with a positional accommodating intraocular lenses (IOL) and to develop a potential optimization of it by minimizing the error associated with the keratometric estimation of the corneal power and by developing a predictive formula for the effective lens position (ELP). Materials and Methods: Clinical data from 25 eyes of 14 patients (age range, 52–77 years) and undergoing cataract surgery with implantation of the accommodating IOL Crystalens HD (Bausch and Lomb) were retrospectively reviewed. In all cases, the calculation of an adjusted IOL power (PIOLadj) based on Gaussian optics considering the residual refractive error was done using a variable keratometric index value (nkadj) for corneal power estimation with and without using an estimation algorithm for ELP obtained by multiple regression analysis (ELPadj). PIOLadj was compared to the real IOL power implanted (PIOLReal, calculated with the SRK-T formula) and also to the values estimated by the Haigis, HofferQ, and Holladay I formulas. Results: No statistically significant differences were found between PIOLReal and PIOLadj when ELPadj was used (P = 0.10), with a range of agreement between calculations of 1.23 D. In contrast, PIOLReal was significantly higher when compared to PIOLadj without using ELPadj and also compared to the values estimated by the other formulas. Conclusions: Predictable refractive outcomes can be obtained with the accommodating IOL Crystalens HD using a variable keratometric index for corneal power estimation and by estimating ELP with an algorithm dependent on anatomical factors and age

Clasificación de lesiones de piel basada en filtros de Gabor y color

CONGRESO ANUAL DE LA SOCIEDAD ESPAÑOLA DE INGENIERÍA BIOMÉDICA (CASEIB 2009) (27) (27.2009.CADIZ, ESPAÑA)Cuando se pretende diagnosticar un posible cáncer de piel, los médicos evalúan la lesión siguiendo diferentes reglas. Aunque la más famosa es la regla ABCD (Asimetría, Borde, Color, Diámetro), una técnica muy empleada en Dermatología es clasificar las lesiones siguiendo un análisis de patrones. Este artículo presenta un método novedoso basado en técnicas de filtrado que clasifica imágenes de color correspondientes a diferentes patrones dermatoscópicos. Hemos evaluado nuestro método usando filtros de Gabor y hemos comparado los resultados obtenidos cuando usamos dos espacios diferentes de color (RGB y L*a*b*) y también cuando consideramos o no la información de color. Para implementar esta tarea hemos evaluado la tasa de clasificación usando 8 vectores diferentes de características. Para cada tipo de vector de características hemos usado el 80% de las imágenes de la base de datos para entrenar una red neuronal fuzzy ARTMAP. El restante 20% de las imágenes fue usado para testear la red. La mejor tasa de clasificación es del 90% cuando usamos el espacio de color L*a*b* para la representación de las imágenes.Junta de Andalucía P06-TIC-0141

Diferencias interoculares medidas mediante microperimetría: comparativa entre sujetos normales y ambliopes

Objetivo: Analizar mediante microperimetría (MP) las diferencias interoculares que existen en sujetos normales, y comparar estos resultados con los de una muestra de sujetos ambliopes. Métodos: Se midieron mediante MP ambos ojos de una muestra de 237 sujetos normales. Las diferencias interoculares se obtuvieron mediante la resta de los valores de cada ojo para: sensibilidad media (Sm), índices P1 y P2, área de la elipse de fijación (BCEA95 y BCEA63), y diámetro horizontal y vertical de esta elipse (H y V). La diferencia interocular normal se estableció mediante el límite superior del IC del 95% de los individuos. Los resultados obtenidos, son comparados con los de 6 sujetos amblíopes, planteándonos dos hipótesis: el ojo dominante (OD) muestra mejores resultados que el ojo amblíope (OA) y esta diferencia es mayor a la encontrada en normales. Resultados: Las diferencias interoculares encontradas en normales fueron: 1.02 dB para Sm, 4.80% y 1.20% para P1 y P2, 3.30°² y 0.37°² para BCEA95 y BCEA63, 0.37° para H y 0.39° para V. En cuanto a los ambliopes, 5/6 sujetos mostraron mayor Sm en el OD, siendo esta diferencia mayor a la encontrada en normales. El análisis de fijación revela que las diferencias interoculares en ambliopes no difieren de las encontradas en normales. Conclusiones: La Sm se ve afectada en el caso de sujetos con ambliopía, encontrando una diferencia entre ojos mayor a la encontrada en normales. En el caso de la fijación, no se encontraron diferencias más allá de las encontradas en normales

Las genealogías de mujeres como práctica de libertad

Este trabajo propone cambios en el sistema educativo actual con el objetivo de que nuestras alumnas salgan del estado de inexistencia social en el que el patriarcado les ha sumido. A este propósito colocaremos las genealogías femeninas en el centro de la educación para crear en el aula un espacio en el que pueda tener lugar la práctica de la libertad. Una libertad que se pone en práctica en las relaciones que establecen nuestras alumnas con las mujeres que forman parte de su genealogía, una relación en la que reconocen en la autoridad de la otra una fuente de valor que permitirá que las mujeres puedan afirmarse como sujetos. <br /

Students frequently ask: ‘Yes but...What is the utility of physics?’

Two Teaching Innovation Projects were carried out in the framework of the subjects ‘Physics I’ and ‘Physics II’ for different Degrees on Engineering at the Engineering High School of the University of Cadiz, Spain, during the 2013-2014 course. The aim of these Projects was to catch the interest of first course students on physical phenomena and principles, a matter frequently considered as ‘difficult’ or even ‘boring’ for them when it is approached from an excessively formal scope. The methodology of the two Projects was based on experiments of Recreational Physics, different toys and devices, and other resources as posters, books and online contents. The Projects were conducted during Theory, Laboratory, and Online classes of Physics I and II, and their results were evaluated from questionnaires to the students. Main conclusions derived from them were: i) a significant increment on the interest of students on Physics and Science; ii) the aim of students for learning more about this kind of recreational physical experiments; and iii) a general sensation of enjoying the study and analysis of physical phenomena by students –and teachers as well–. In addition, students manifested their interest in this methodology to be applied to other Engineering subjects of their Degrees