44 results on '"Arboleda, Carolina"'
Search Results
2. Ethical and scientific considerations when making decisions to euthanise companion animals
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Giraldo-Arboleda, Carolina, primary, Zapata-Martinez, Juan Carlos, additional, Osorio-Morales, Lina, additional, and Pedraza-Ordonez, Francisco, additional
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- 2023
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3. Grating-based interferometry and hybrid photon counting detectors: Towards a new era in X-ray medical imaging
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Gkoumas, Spyridon, Wang, Zhentian, Abis, Matteo, Arboleda, Carolina, Tudosie, George, Donath, Tilman, Brönnimann, Christian, Schulze-Briese, Clemens, and Stampanoni, Marco
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- 2016
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4. Microbubbles as a contrast agent in grating interferometry mammography: an ex vivo proof-of-mechanism study
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Lång, Kristina, Arboleda, Carolina, Forte, Serafino, Wang, Zhentian, Prevrhal, Sven, Koehler, Thomas, Kuhn, Norbert, David, Bernd, Jefimovs, Konstantins, Kubik-Huch, Rahel A., and Stampanoni, Marco
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- 2019
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5. Correction to: Towards clinical grating-interferometry mammography
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Arboleda, Carolina, Wang, Zhentian, Jefimovs, Konstantins, Koehler, Thomas, Van Stevendaal, Udo, Kuhn, Norbert, David, Bernd, Prevrhal, Sven, Lång, Kristina, Forte, Serafino, Kubik-Huch, Rahel Antonia, Leo, Cornelia, Singer, Gad, Marcon, Magda, Boss, Andreas, Roessl, Ewald, and Stampanoni, Marco
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- 2020
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6. X-ray grating interferometry design for the 4D GRAPH-X system
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PATERA, ALESSANDRA, primary, Arboleda, Carolina, additional, Ferrero, Veronica, additional, Fiorina, Elisa, additional, Jefimovs, Konstantins, additional, Lo Giudice, Alessandro, additional, Mas Milian, Felix, additional, Mereu, Paolo, additional, Pallotta, Stefania, additional, Ramello, Luciano, additional, Re, Alessandro, additional, Visca, Lorenzo, additional, and Cerello, Piergiorgio, additional
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- 2021
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7. Fabrication of X-ray Gratings for Interferometric Imaging by Conformal Seedless Gold Electroplating
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Jefimovs, Konstantins, primary, Vila-Comamala, Joan, additional, Arboleda, Carolina, additional, Wang, Zhentian, additional, Romano, Lucia, additional, Shi, Zhitian, additional, Kagias, Matias, additional, and Stampanoni, Marco, additional
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- 2021
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8. Can grating interferometry-based mammography discriminate benign from malignant microcalcifications in fresh biopsy samples?
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Forte, Serafino, primary, Wang, Zhentian, additional, Arboleda, Carolina, additional, Lång, Kristina, additional, Singer, Gad, additional, Kubik-Huch, Rahel A., additional, and Stampanoni, Marco, additional
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- 2020
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9. Eclipse Solar
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Arboleda, Carolina, primary and Whang, Mikyoung, additional
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- 2015
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10. The trigonometric orthogonality of phase‐stepping curves in grating‐based x‐ray phase‐contrast imaging: Integral property and its implications for noise optimization
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Wu, Chengpeng, primary, Zhang, Li, additional, Chen, Zhiqiang, additional, Xing, Yuxiang, additional, Li, Xinbin, additional, Zhu, Xiaohua, additional, Arboleda, Carolina, additional, Wang, Zhentian, additional, and Gao, Hewei, additional
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- 2019
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11. Towards clinical grating-interferometry mammography
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Arboleda, Carolina, primary, Wang, Zhentian, additional, Jefimovs, Konstantins, additional, Koehler, Thomas, additional, Van Stevendaal, Udo, additional, Kuhn, Norbert, additional, David, Bernd, additional, Prevrhal, Sven, additional, Lång, Kristina, additional, Forte, Serafino, additional, Kubik-Huch, Rahel Antonia, additional, Leo, Cornelia, additional, Singer, Gad, additional, Marcon, Magda, additional, Boss, Andreas, additional, Roessl, Ewald, additional, and Stampanoni, Marco, additional
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- 2019
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12. Investigation of suitable biopsy markers for grating-based phase contrast mammography
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Arboleda, Carolina, Wang, Zhentian, Forte, Serafino, Kubik-Huch, Rahel A, Stampanoni, Marco, University of Zurich, and Arboleda, Carolina
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170 Ethics ,3105 Instrumentation ,610 Medicine & health ,10237 Institute of Biomedical Engineering ,2610 Mathematical Physics - Published
- 2017
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13. Estrategia de intervención terapéutica para el mejoramiento de las relaciones interpersonales en el personal de salud del hospital referencial Ferreñafe
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Castañeda Arboleda, Carolina Elizabeth and Callejas Torres, Juan Carlos
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Estrategia de Intervención Terapéutica ,Personal de Salud ,Relaciones Interpersonales ,purl.org/pe-repo/ocde/ford#5.01.02 [http] - Abstract
Esta investigación tiene como objetivo aplicar la estrategia de intervención terapéutica basada en el proceso de formación de los valores comunicación, respeto, asertividad y empatía, desde las tendencias históricas en el proceso de formación de valores y su dinámica; la investigación es experimental, diseño cuasi experimental y esta validado por expertos; también se evalúa el nivel de relaciones interpersonales en el personal de salud; por ello es que se aplica la correlación entre la estrategia de intervención terapéutica basada en el proceso de formación de los valores y el mejoramiento de las relaciones interpersonales. El análisis de los resultados nos informa que la falta de valores en el personal de salud ha generado estrategias de evaluación e intervención dirigidas a ayudar a los trabajadores que presentan dificultades en el área de las relaciones interpersonales, por lo que el aprendizaje de los valores, se produce siempre en contextos interpersonales, gracias a la interacción con los demás. Por ello se concluye en una aportación en la práctica de los valores y mostrar visiblemente un cambio en el manejo de las relaciones de las relaciones interpersonales entre todo el personal de salud, los cambios lo asumieron con mucha madurez intelectual y emocional en la práctica de su jornada diaria. Además es muy importante la comunicación, conductas asertivas y el respeto. Tesis
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- 2018
14. The trigonometric orthogonality of phase‐stepping curves in grating‐based x‐ray phase‐contrast imaging: Integral property and its implications for noise optimization.
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Wu, Chengpeng, Zhang, Li, Chen, Zhiqiang, Xing, Yuxiang, Li, Xinbin, Zhu, Xiaohua, Arboleda, Carolina, Wang, Zhentian, and Gao, Hewei
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X-ray imaging ,FOURIER series ,NOISE ,FOURIER analysis ,INFORMATION retrieval - Abstract
Purpose: Grating‐based x‐ray phase‐contrast imaging (GPCI) is a promising technique for clinical applications as it can provide two newly emerging imaging modalities (differential phase‐contrast and dark‐field contrast) in addition to the conventional absorption contrast. As far, phase‐stepping strategy is the most commonly used approach in GPCI to indirectly acquire differential phase‐contrast and dark‐field contrast. It is known that the obtained phase‐stepping curves (PSCs) have the cosine property and the convolution property, leading to two types of information retrieval approaches in literature: the Fourier component analysis and the multi‐order moment analysis. The purpose of this paper is to derive a new property of PSCs and apply the property to noise optimization for information retrieval. Methods: Based on the cosine expression of the flat PSC without the sample and the well‐established convolution relationship between the flat PSC and the sample PSC, we reveal an important integral property of PSCs: the inner product of PSCs and an arbitrary function contains only zero‐order and first‐order components in the Fourier series. Furthermore, we apply the property to the direct multi‐order moment analysis and propose a set of generalized forms including an optimal one in the presence of noise. Results: To validate the effectiveness of our analysis, we compared the simulated and real experiment results retrieved by the original direct multi‐order moment analysis with the ones retrieved by our proposed noise‐optimal form. A significant improvement of noise performance by our method is observed and the improvement ratio in differential phase‐contrast is consistent with our theoretical calculation (39.2%). Conclusions: In this paper, we reveal a new integral property of the acquired PSCs with and without samples in GPCI, which can be applied to information retrieval approaches like the direct multi‐order moment analysis. Then we optimize these approaches to improve the noise performance, offering great potentials of dose reduction in practical applications. [ABSTRACT FROM AUTHOR]
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- 2020
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15. Development of Laboratory Grating-based X-ray Phase Contrast Microtomography for Improved Pathology
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Vila-Comamala, Joan, primary, Arboleda, Carolina, additional, Romano, Lucia, additional, Kuo, Willy, additional, Lang, Kristina, additional, Jefimovs, Konstantins, additional, Wang, Zhentian, additional, Singer, Gad, additional, Vine, David, additional, Yun, Wenbing, additional, and Stampanoni, Marco, additional
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- 2018
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16. ESTRATEGIA DE INTERVENCIÓN TERAPÉUTICA PARA EL MEJORAMIENTO DE LAS RELACIONES INTERPESONALES DEL HOSPITAL FERRAÑAFE
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Castañeda Arboleda, Carolina E., primary, Callejas Torres, Juan Carlos, primary, and Pérez Martinto, Pedro Carlos, primary
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- 2018
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17. Impacto organizacional del tratamiento de las cuentas por cobrar bajo NIIF
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Ruiz Arboleda, Carolina, Moratto Muñoz, Daniela, and Peláez Arbeláez, Paula Andrea
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N/A - Published
- 2017
18. IN VITRO ANTI-HIV-1 ACTIVITY OF THE ENZYMATIC EXTRACT ENRICHED WITH LACCASE PRODUCED BY THE FUNGI GANODERMA SP. AND LENTINUS SP
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FLÓREZ-SAMPEDRO, Laura, ZAPATA, Wildeman, OROZCO, Lina P, MEJÍA, Amanda I, ARBOLEDA, Carolina, and RUGELES, María T
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Human immunodeficiency virus type 1 (HIV-1) ,lacasa ,Lentinus ,natural products ,productos naturales ,antiviral activity ,Ganoderma ,Virus de la Inmunodeficiencia Humana tipo 1 (VIH-1) ,actividad antiviral ,laccase - Abstract
Background: Natural compounds are a good source for the development of antiretroviral drugs with low cytotoxicity. The laccase enzyme, produced by fungi of the genera Ganoderma sp. and Lentinus sp., inhibits the reverse transcriptase (RT) of the human immunodeficiency virus 1 (HIV-1), in cell-free models in vitro. Objetives: In this study we evaluated the anti-HIV-1 activity of the enzymatic extracts (EE) enriched with laccase, produced by two native species of fungi of the same genera in an in vitro cell culture model. Methods: The inhibition of viral replication was performed using the U373-MAGI cell line infected with recombinant viruses in the presence/absence of the EE and 48 hpi, the percentage of infected cells was evaluated by flow cytometry for green fluorescent protein -GFP- and ELISA for p24. The inhibition of the RT was determined by quantification of early and late products of reverse transcription using quantitative PCR. Results: The EEs from Ganoderma sp. and Lentinus sp. inhibited the replication of HIV-1 between 80 and 90% and decreased the production of early and late transcripts between 55,5%-91,3% and 82,1%-93,6% respectively. The EE from Lentinus sp. had the best selectivity index (SI: 8.3). Conclusions: These results suggest the potential anti-HIV-1 activity of the EE for the exploration of an alternative therapy against HIV-1 infection. RESUMEN Antecedentes: Los compuestos naturales son una buena fuente para el desarrollo de fármacos antirretrovirales con baja citotoxicidad. La enzima lacasa, producida por hongos del género Ganoderma sp. y Lentinus sp., inhibe la transcriptasa reversa (TR) del virus de la inmunodeficiencia humana tipo 1 (VIH-1), en modelos in vitro, libres de células. Objetivos: En este estudio se evaluó la actividad anti-VIH-1 del extracto enzimático (EE) enriquecido con lacasa, producida por dos especies nativas de hongos de los mismos géneros en un modelo in vitro de cultivo celular. Métodos: La inhibición de la replicación viral se realizó usando la línea celular U373-MAGI infectada con virus recombinantes en la presencia/ausencia del EE y 48 hpi, el porcentaje de células infectadas se evaluó mediante citometría de flujo para GFP y ELISA para p24. La inhibición de la TR se determinó mediante la cuantificación de los productos tempranos y tardíos de la transcripción reversa utilizando una PCR cuantitativa. Resultados: El EE de Ganoderma sp. y Lentinus sp. inhibió la replicación del VIH-1 entre el 80 y 90% y disminuyó la producción de transcriptos tempranos y tardíos entre el 55,5% -91,3% y 82,1% -93,6%, respectivamente. El EE de Lentinus sp. mostró el mejor índice de selectividad (IS: 8.3). Conclusiones: Estos resultados sugieren el potencial anti-VIH-1 del EE para la exploración de una terapia alternativa contra la infección por el VIH-1.
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- 2016
19. Sensitivity-based optimization for the design of a grating interferometer for clinical X-ray phase contrast mammography
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Arboleda, Carolina, primary, Wang, Zhentian, additional, Koehler, Thomas, additional, Martens, Gerhard, additional, Van Stevendaal, Udo, additional, Bartels, Matthias, additional, Villanueva-Perez, Pablo, additional, Roessl, Ewald, additional, and Stampanoni, Marco, additional
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- 2017
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20. Sensitivity-based optimization for the design of a grating interferometer for clinical X-ray phase contrast mammography
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Arboleda, Carolina, Wang, Zhentian, Koehler, Thomas, Martens, Gerhard, Van Stevendaal, Udo, Bartels, Matthias, Villanueva-Perez, Pablo, Roessl, Ewald, Stampanoni, Marco, Arboleda, Carolina, Wang, Zhentian, Koehler, Thomas, Martens, Gerhard, Van Stevendaal, Udo, Bartels, Matthias, Villanueva-Perez, Pablo, Roessl, Ewald, and Stampanoni, Marco
- Abstract
An X-ray grating interferometer (GI) suitable for clinical mammography must comply with quite strict dose, scanning time and geometry limitations, while being able to detect tumors, microcalcifications and other abnormalities. Such a design task is not straightforward, since obtaining optimal phase-contrast and dark-field signals with clinically compatible doses and geometrical constraints is remarkably challenging. In this work, we present a wave propagation based optimization that uses the phase and dark-field sensitivities as figures of merit. This method was used to calculate the optimal interferometer designs for a commercial mammography setup. Its accuracy was validated by measuring the visibility of polycarbonate samples of different thicknesses on a Talbot-Lau interferometer installed on this device and considering some of the most common grating imperfections to be able to reproduce the experimental values. The optimization method outcomes indicate that small grating pitches are required to boost sensitivity in such a constrained setup and that there is a different optimal scenario for each signal type.
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- 2017
21. Sistematización de una experiencia pedagógica de educación primaria en una institución educativa del Municipio de la Celia/Risaralda, Colombia
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Osorio Mejía, Luisa Fernanda, Gómez López, Paola Vanessa, Henao Arboleda, Carolina, Osorio Mejía, Luisa Fernanda, Gómez López, Paola Vanessa, and Henao Arboleda, Carolina
- Abstract
Con la realización de esta investigación de tipo cualitativo se busca la sistematización de la experiencia de un docente del grado segundo de una Institución Educativa del municipio de La Celia Risaralda,con la implementación de una unidad didáctica “¿Como generar conciencia ambiental a partir de las experiencias vividas hasta el momento con los silos de café? diseñada mediante la metodología del programa Pequeños científicos, desarrollando así la competencia científica en los estudiantes promoviendo la indagación y la argumentación de problemáticas asociadas a su entorno. Esta metodología permite la integración y participación de los estudiantes en su proceso de aprendizaje.
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- 2016
22. Mercadeo, Vallenpaz
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Mora Arboleda , Carolina, Lombana Astaiza , Vanessa, Gartner Villa, Ángela María, and Asesor Tesis
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Marketing ,Investigación de mercadeo ,Posicionamiento ,Marca ,Estrategias de mercadeo ,Strategy ONG ,Estrategia en ONG ,Mercadeo ,Mercado campesino ,Trabajos de grado ,Producción intelectual registrada - Universidad Icesi ,VallenPaz ,Farmers Market ,Positioning - Abstract
El siguiente proyecto de grado trabajó el nivel de posicionamiento de la marca Cosechas de Paz de la Corporación para el desarrollo y paz del suroccidente colombiano, VallenPaz. Análisis desarrollado en el segmento de consumidores de productos campesinos orgánicos, mediante una investigación cuantitativa por medio de encuestas a consumidores y entrevistas a personal de la corporación. Donde se obtuvo el perfil del mercado objetivo, compuesto por mujeres de treinta años en adelante, de estratos socioeconómicos tres y cuatro, con familias en promedio de tres a cuatro miembros. Igualmente identificamos las diferentes asociaciones a la marca, entre las cuales se encuentran la buena calidad, buen sabor, libre de químicos y sobresale la contribución que estos productos hacen a la consecución de la paz. Además se estableció que el nivel de recordación de la marca es bajo en el segmento de la categoría, a pesar de que esta cuenta con una imagen favorable entre sus consumidores. Todo esto se ejecutó con el fin de evaluar la efectividad de las decisiones estratégicas de mercadeo, las cuales a través del indicador de posicionamiento se pueden calificar como poco efectivas para el segmento objetivo. In this Project we worked in the level of positioning of the brand Cosechas de Paz of the corporation for development and peace of southwestern of Colombia, VallenPaz. The analysis was development in the segment of consumers of organic farmer’s products, through to quantitative investigation with consumer surveys and interviews with staff of the corporation. Where the profile was obtained Target Market, composed for women of thirty years or more with families of 3 or 4 members. Also we could identify the different associations to the Brand, good quality, and good taste, free of chemicals and excels the contribution to the products to the peace. Also we established that the level of brand recall is low in the segment of the category and the brand has a good image in the consumers. All this was carried for the interest out to evaluate the Effectiveness of strategic marketing decisions through the positioning indicator in the category of these products.
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- 2014
23. Diseño y construcción de un prototipo de interfaz cerebro-computador para facilitar la comunicación de personas con discapacidad motora (Design and construction of a brain-computer interface prototype to facilitate the communication of people with motor
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Arboleda, Carolina, García, Eliana, Posada, Alejandro, and Torres, Róbinson
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potencial evocado cognitivo P300 ,motor disability ,interfaz cerebro-computador (ICC) ,discapacidad motora ,el ,augmentative and alternative communication ,procesamiento de señales. Keywords ,electroencefalografía ,comunicación aumentativa y alternativa - Abstract
Una interfaz cerebro-computador (ICC) es un sistema de comunicación que permite generar una señal de control a partir de señales cerebrales como los ritmos sensorimotores y los potenciales evocados y, por consiguiente, constituye una alternativa novedosa de comunicación para personas con discapacidad motora seria (como aquellas que padecen esclerosis lateral amiotrófica, ELA). Este proyecto propone el desarrollo de un prototipo de ICC basado en el registro de potenciales evocados cognitivos P-300 mediante electroencefalografía. El prototipo usa un electroencefalógrafo de seis canales para la adquisición de las señales, y por medio de una matriz de estimulación visual que contiene las letras del abecedario e íconos asociados a ellas permite que el usuario escriba palabras o elabore mensajes con los íconos. Para procesar las señales (filtración, diezmado, entre otros) se utilizaron los programas BCI2000 y MATLAB 7.0. Este último se empleó para programar tres algoritmos lineales de traslación (análisis lineal del discriminante, solución por mínimos cuadrados y análisis lineal del discriminante paso a paso) que permitieran traducir los potenciales evocados en señales de comunicación.Abstract: A brain-computer interface (BCI) is a communication system that translates a brain signal (e.g. sensorimotor rhythms, evoked potentials) into a control signal and, therefore, constitutes an innovative communication alternative for people with severe motor disability (such as patients with amyotrophic lateral sclerosis). This project proposes the development of a BCI prototype based on the recording of P300 cognitive potentials using electroencephalography. The prototype uses a six-channel electroencephalograph to acquire the signals, and through a visual stimulation matrix containing the letters of the alphabet and icons associated to each one gives the user the possibility of writing words or elaborating messages with the icons. To process the signals (filtering and decimation, among other methods), the software BCI2000 and MATLAB 7.0 were used. The latter was used to program three different linear translation algorithms (linear discriminant analysis, least squares analysis and stepwise linear discriminant analysis), in order to translate the recorded evoked potentials into communication signals. Una interfaz cerebro-computador (ICC) es un sistema de comunicación que permite generar una señal de control a partir de señales cerebrales como los ritmos sensorimotores y los potenciales evocados y, por consiguiente, constituye una alternativa novedosa de comunicación para personas con discapacidad motora seria (como aquellas que padecen esclerosis lateral amiotrófica, ELA). Este proyecto propone el desarrollo de un prototipo de ICC basado en el registro de potenciales evocados cognitivos P-300 mediante electroencefalografía. El prototipo usa un electroencefalógrafo de seis canales para la adquisición de las señales, y por medio de una matriz de estimulación visual que contiene las letras del abecedario e íconos asociados a ellas permite que el usuario escriba palabras o elabore mensajes con los íconos. Para procesar las señales (filtración, diezmado, entre otros) se utilizaron los programas BCI2000 y MATLAB 7.0. Este último se empleó para programar tres algoritmos lineales de traslación (análisis lineal del discriminante, solución por mínimos cuadrados y análisis lineal del discriminante paso a paso) que permitieran traducir los potenciales evocados en señales de comunicación.Abstract: A brain-computer interface (BCI) is a communication system that translates a brain signal (e.g. sensorimotor rhythms, evoked potentials) into a control signal and, therefore, constitutes an innovative communication alternative for people with severe motor disability (such as patients with amyotrophic lateral sclerosis). This project proposes the development of a BCI prototype based on the recording of P300 cognitive potentials using electroencephalography. The prototype uses a six-channel electroencephalograph to acquire the signals, and through a visual stimulation matrix containing the letters of the alphabet and icons associated to each one gives the user the possibility of writing words or elaborating messages with the icons. To process the signals (filtering and decimation, among other methods), the software BCI2000 and MATLAB 7.0 were used. The latter was used to program three different linear translation algorithms (linear discriminant analysis, least squares analysis and stepwise linear discriminant analysis), in order to translate the recorded evoked potentials into communication signals.
- Published
- 2013
24. Total liver fat quantification using three-dimensional respiratory self-navigated MRI sequence
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Arboleda, Carolina, primary, Aguirre-Reyes, Daniel, additional, García, María Paz, additional, Tejos, Cristián, additional, Muñoz, Loreto, additional, Miquel, Juan Francisco, additional, Irarrazaval, Pablo, additional, Andia, Marcelo E., additional, and Uribe, Sergio, additional
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- 2015
- Full Text
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25. Tilted-grating approach for scanning-mode X-ray phase contrast imaging
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Arboleda, Carolina, Wang, Zhentian, Stampanoni, Marco, Arboleda, Carolina, Wang, Zhentian, and Stampanoni, Marco
- Abstract
Among the existent X-ray phase-contrast modalities, grating interferometry appears as a very promising technique for commercial applications, since it is compatible with conventional X-ray tubes and is robust from a mechanical point of view. However, since applications such as medical imaging and homeland security demand covering a considerable field of view, the fabrication of large-area gratings, which is known to be challenging and expensive, would be needed. A scanning setup is a good solution for this issue, because it uses cheaper line instead of large-area 2D detectors and, therefore, would require smaller gratings. In such a setup, the phase-retrieval using the conventional phase-stepping approach would be very slow, so having a faster method to record the signals becomes fundamental. To tackle this problem, we present a scanning-mode grating interferometer design, in which a grating is tilted to form Moiré fringes perpendicular to the grating lines. The sample is then translated along the fringes, so each line detector records a different phase step for each slice of the sample. This new approach was tested both in a simulated scenario and in an experimental setting, and its performance was quantitatively satisfactory compared to the traditional phase-stepping method and another existing scanning-mode technique.
- Published
- 2014
26. Tilted-grating approach for scanning-mode X-ray phase contrast imaging
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Arboleda, Carolina, primary, Wang, Zhentian, additional, and Stampanoni, Marco, additional
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- 2014
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27. Wavelet-based noise-model driven denoising algorithm for differential phase contrast mammography
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Arboleda, Carolina, Wang, Zhentian, Stampanoni, Marco, Arboleda, Carolina, Wang, Zhentian, and Stampanoni, Marco
- Published
- 2013
28. Cultura, política industrial y competitividad internacional de las pyme en Colombia
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Bustamante Zapata, Luis Fernando, Arboleda, Carolina, Gutiérrez Ossa, Jahir Alexander, Bustamante Zapata, Luis Fernando, Arboleda, Carolina, and Gutiérrez Ossa, Jahir Alexander
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- 2010
29. Diseño y construcción de un prototipo de interfaz cerebro-computador para facilitar la comunicación de personas con discapacidad motora
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García, Eliana, Posada, Alejandro, Arboleda, Carolina, Torres, Róbinson, García, Eliana, Posada, Alejandro, Arboleda, Carolina, and Torres, Róbinson
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- 2009
30. Image-quality optimization for dual energy computed tomography (dect) three-material decomposition
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Arboleda, Carolina, Pelc, Norbert J, Arboleda, Carolina, and Pelc, Norbert J
- Abstract
Dual energy computed tomography, which consists of the acquisition of two images of a given region of interest using two different x-ray energies, has been used to decompose images. For example, it has been proposed to estimate the degree of stenosis of blood vessels with calcified plaques. Pragmatic realities, though, such as beam hardening, scattered radiation and mostly quantum noise, reduce the ideal of a perfect decomposition. In this study, a dual energy separation method for iodinated contrast media, cortical bone and soft tissue was implemented; afterwards, it was tested in simulated noiseless and noisy situations. The noise propagation was modeled mathematically, and an image-quality optimization technique regarding the right distribution of radiation dose between the high and low energy images was proposed. The results obtained suggest that in the absence of noise and using mono-energetic beams, an accurate separation is possible, but when noise is added and poly-chromatic spectra used this decomposition becomes more challenging., La tomografía computarizada de dos energías, que consiste en la adquisición de dos imágenes de una región de interés dada usando rayos X de dos energías distintas, ha sido utilizada para descomponer imágenes. Por ejemplo, esta técnica ha sido propuesta para estimar el grado de estenosis de vasos sanguíneos obstruidos con placas de calcio. Sin embargo, fenómenos como el endurecimiento del rayo, la radiación dispersada y principalmente el ruido cuántico, impiden que esta separación sea perfecta. En este estudio, se implementó un método de separación de medio de contraste yodado, tejido blando y hueso cortical; este se evaluó en simulaciones, tanto en presencia como en ausencia de ruido. Posteriormente, se modeló matemáticamente la propagación del ruido y, con base en los resultados de estos modelos, se propuso una técnica de optimización de la imagen basada en la distribución adecuada de la dosis de radiación entre las imágenes de energías alta y baja. Los resultados evidencian que en ausencia de ruido y con rayos mono-energéticos, es posible obtener una separación precisa, pero cuando se adiciona ruido a las imágenes y se trabaja con espectros policromáticos, la descomposición resulta más complicada.
- Published
- 2009
31. Fungi autochthonous from the tropical forest of Colombia for dye decolourisation and ligninolytic enzymes production
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Arboleda, Carolina, Mejia, Amanda Ines, Franco-Molano, Ana E., Jimenez-Tobon, Gloria, Penninckx, Michel, Arboleda, Carolina, Mejia, Amanda Ines, Franco-Molano, Ana E., Jimenez-Tobon, Gloria, and Penninckx, Michel
- Abstract
info:eu-repo/semantics/published
- Published
- 2008
32. Autochthonous white rot fungi from the tropical forest of Colombia for dye decolourisation and ligninolytic enzymes production
- Author
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Arboleda, Carolina, Mejia, Amanda Ines, Franco-Molano, Ana E., Jimenez-Tobon, Gloria, Penninckx, Michel, Arboleda, Carolina, Mejia, Amanda Ines, Franco-Molano, Ana E., Jimenez-Tobon, Gloria, and Penninckx, Michel
- Abstract
SCOPUS: ar.j, info:eu-repo/semantics/published
- Published
- 2008
33. Tomografía computarizada por rayos x: Fundamentos y actualidad
- Author
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Ramírez Giraldo, Juan Carlos, Arboleda, Carolina, McCollough, Cynthia H, Ramírez Giraldo, Juan Carlos, Arboleda, Carolina, and McCollough, Cynthia H
- Abstract
This paper reviews the fundamentals of x-ray computed tomography. It starts by summarizing the early days of the technique and its evolution through time, as well as the physical principles of x-ray production. Subsequently, the mathematical principles of image reconstruction are discussed with emphasis in both analytical and iterative reconstruction methods. A complete section is dedicated to review the main concepts related with the risks of ionizing radiation, and discuss some of the most recent controversies about CT radiation and how those risks affect scanning protocols. Finally, based on the most recent advances and trends in CT, the paper discuss about those areas, which, presumably, will be the research focus of CT in the near future., Este artículo presenta una revisión de los fundamentos de la tomografía computarizada, empezando por un recuento de los inicios y progresos de esta técnica a través del tiempo, y continuando con una descripción de los principios físicos que rigen la producción de los rayos X. El artículo también discute las bases matemáticas para la reconstrucción de las imágenes a partir de proyecciones utilizando métodos analíticos o iterativos. En una sección independiente, se revisan los conceptos más importantes relacionados con los riesgos de la radiación ionizante y se discuten investigaciones recientes, algunas polémicas, acerca de los beneficios y riesgos asociados con la tomografía computarizada y cómo estos afectan los protocolos de adquisición de las imágenes. Finalmente, con base en los avances científicos y tendencias más recientes, el artículo propone las áreas que, presumiblemente, continuarán siendo el centro de atención de la tomografía computarizada de rayos X en los próximos años.
- Published
- 2008
34. Elimination of Bisphenol A and Triclosan Using the Enzymatic System of Autochthonous Colombian Forest Fungi
- Author
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Arboleda, Carolina, primary, Cabana, H., additional, De Pril, E., additional, Jones, J. Peter, additional, Jiménez, G. A., additional, Mejía, A. I., additional, Agathos, S. N., additional, and Penninckx, M. J., additional
- Published
- 2013
- Full Text
- View/download PDF
35. Wavelet-based noise-model driven denoising algorithm for differential phase contrast mammography
- Author
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Arboleda, Carolina, primary, Wang, Zhentian, additional, and Stampanoni, Marco, additional
- Published
- 2013
- Full Text
- View/download PDF
36. Control de mouse para computador mediante potenciales eléctricos oculares
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Arboleda, Carolina, García Cossio, Eliana, Palacio Ochoa, Marcela, Arboleda, Carolina, García Cossio, Eliana, and Palacio Ochoa, Marcela
- Abstract
The use of computers and associated technology, has promoted the development of more comfortable and efficient hardware devices. Many handicapped people can not access to this technology. As a result, innovative mechanisms have been designed to attend the requirements of these people. One of such mechanisms has been the control through biopotentials. This article presents the construction of a mouse prototype, which allows horizontal displacements in response to left and right ocular movements that are registered by instrumentation amplifiers, processed and microcontrolled., El uso creciente de los computadores, y toda la tecnología asociada, ha promovido la creación de dispositivos de hardware cada vez más cómodos y eficientes para el usuario. Un número significativo de personas en situación de discapacidad no puede acceder a esta tecnología. Por esa razón, se han diseñado mecanismos, distintos a los tradicionales, para atender las necesidades de dichas personas. Entre estos mecanismos se han utilizado sistemas de control basados en biopotenciales. En este artículo, se presenta la construcción de un prototipo de mouse, cuyo movimiento en sentido horizontal es determinado por las señales eléctricas provenientes de desplazamientos oculares derecha-izquierda, que son captados por amplificadores de biopotenciales y posteriormente procesados y microcontrolados.
- Published
- 2007
37. Total liver fat quantification using three-dimensional respiratory self-navigated MRI sequence.
- Author
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Arboleda, Carolina, Aguirre‐Reyes, Daniel, García, María Paz, Tejos, Cristián, Muñoz, Loreto, Miquel, Juan Francisco, Irarrazaval, Pablo, Andia, Marcelo E., and Uribe, Sergio
- Abstract
Purpose MRI can produce quantitative liver fat fraction (FF) maps noninvasively, which can help to improve diagnoses of fatty liver diseases. However, most sequences acquire several two-dimensional (2D) slices during one or more breath-holds, which may be difficult for patients with limited breath-holding capacity. A whole-liver 3D FF map could also be obtained in a single acquisition by applying a reliable breathing-motion correction method. Several correction techniques are available for 3D imaging, but they use external devices, interrupt acquisition, or jeopardize the spatial resolution. To overcome these issues, a proof-of-concept study introducing a self-navigated 3D three-point Dixon sequence is presented here. Methods A respiratory self-gating strategy acquiring a center k-space profile was integrated into a three-point Dixon sequence. We obtained 3D FF maps from a water-fat emulsions phantom and fifteen volunteers. This sequence was compared with multi-2D breath-hold and 3D free-breathing approaches. Results Our 3D three-point Dixon self-navigated sequence could correct for respiratory-motion artifacts and provided more precise FF measurements than breath-hold multi-2D and 3D free-breathing techniques. Conclusion Our 3D respiratory self-gating fat quantification sequence could correct for respiratory motion artifacts and yield more-precise FF measurements. Magn Reson Med 76:1400-1409, 2016. © 2015 International Society for Magnetic Resonance in Medicine [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
38. DISEÑO Y CONSTRUCCIÓN DE UN PROTOTIPO DE INTERFAZ CEREBRO-COMPUTADOR PARA FACILITAR LA COMUNICACIÓN DE PERSONAS CON DISCAPACIDAD MOTORA.
- Author
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ARBOLEDA, CAROLINA, GARCÍA, ELIANA, POSADA, ALEJANDRO, and TORRES, RÓBINSON
- Subjects
- *
BRAIN-computer interfaces , *COMPUTER networks , *MOVEMENT disorders , *COMPUTERS & people with disabilities , *ELECTROENCEPHALOGRAPHY , *ALGORITHMS - Abstract
A brain-computer interface (BCI) is a communication system that translates a brain signal (e.g. sensorimotor rhythms, evoked potentials) into a control signal and, therefore, constitutes an innovative communication alternative for people with severe motor disability (such as patients with amyotrophic lateral sclerosis). This project proposes the development of a BCI prototype based on the recording of P300 cognitive potentials using electroencephalography. The prototype uses a six-channel electroencephalograph to acquire the signals, and through a visual stimulation matrix containing the letters of the alphabet and icons associated to each one gives the user the possibility of writing words or elaborating messages with the icons. To process the signals (filtering and decimation, among other methods), the software BCI2000 and MATLAB 7.0 were used. The latter was used to program three different linear translation algorithms (linear discriminant analysis, least squares analysis and stepwise linear discriminant analysis), in order to translate the recorded evoked potentials into communication signals. [ABSTRACT FROM AUTHOR]
- Published
- 2009
39. Microbubbles as a contrast agent in grating interferometry mammography: an ex vivo proof-of-mechanism study
- Author
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Lång, Kristina, Arboleda, Carolina, Forte, Serafino, Wang, Zhentian, Prevrhal, Sven, Koehler, Thomas, Kuhn, Norbert, David, Bernd, Jefimovs, Konstantins, Kubik-Huch, Rahel A., and Stampanoni, Marco
- Subjects
Interferometry ,Microbubbles ,Contrast media ,education ,Phantoms (imaging) ,3. Good health ,Mammography - Abstract
Grating interferometry mammography (GIM) is an experimental breast imaging method at the edge of being clinically implemented. Besides attenuation, GIM can measure the refraction and scattering of x-rays resulting in differential phase contrast (DPC) and dark-field (DF) images. In this exploratory study, we assessed the feasibility of using microbubbles as a contrast agent in GIM. Two millilitres of microbubbles and iodine were respectively injected into ex vivo breast phantoms, consisting of fresh chicken breasts. Native and postcontrast images were acquired with a clinically compatible GIM setup, operated at 38 kVp, 14-s acquisition time, and with a dose of 1.3 mGy. The visibility of the contrast agents was analysed in a side-by-side comparison by three radiologists. The contrast-to-noise-ratio (CNR) was calculated for each contrast agent. We found that both contrast agents were judged to be visible by the readers. The mean CNR was 3.1 ± 1.9 for microbubbles in DF and 24.2 ± 6.5 for iodine in attenuation. In conclusion, this is a first proof-of-mechanism study that microbubbles could be used as a contrast agent in clinically compatible GIM, due to their scattering properties, which implies the potential use of a contrast agent with a high safety profile in x-ray-based breast imaging., European Radiology Experimental, 3 (1), ISSN:2509-9280
40. Towards clinical grating-interferometry mammography
- Author
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Arboleda, Carolina, Wang, Zhentian, Jefimovs, Konstantins, Koehler, Thomas, van Stevendaal, Udo, Kuhn, Norbert, David, Bernd, Prevrhal, Sven, Lång, Kristina, Forte, Serafino, Kubik-Huch, Rahel Antonia, Leo, Cornelia, Singer, Gad, Marcon, Magda, Boss, Andreas, Roessl, Ewald, and Stampanoni, Marco
- Subjects
Interferometry ,Phase contrast ,3. Good health ,Mammography - Abstract
Objectives Grating-interferometry-based mammography (GIM) might facilitate breast cancer detection, as several research works have demonstrated in a pre-clinical setting, since it is able to provide attenuation, differential phase contrast, and scattering images simultaneously. In order to translate this technique to the clinics, it has to be adapted to cover a large field-of-view within a clinically acceptable exposure time and radiation dose. Methods We set up a grating interferometer that fits into a standard mammography system and fulfilled the aforementioned conditions. Here, we present the first mastectomy images acquired with this experimental device. Results and conclusion Our system performs at a mean glandular dose of 1.6 mGy for a 5-cm-thick, 18%-dense breast, and a field-of-view of 26 × 21 cm2. It seems to be well-suited as basis for a clinical-environment device. Further, dark-field signals seem to support an improved lesion visualization. Evidently, the effective impact of such indications must be evaluated and quantified within the context of a proper reader study. Key Points • Grating-interferometry-based mammography (GIM) might facilitate breast cancer detection, since it is sensitive to refraction and scattering and thus provides additional tissue information. • The most straightforward way to do grating-interferometry in the clinics is to modify a standard mammography device. • In a first approximation, the doses given with this technique seem to be similar to those of conventional mammography., European Radiology, 30, ISSN:0938-7994, ISSN:1432-1084
41. Towards clinical grating-interferometry mammography
- Author
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Andreas Boss, Cornelia Leo, Marco Stampanoni, Sven Prevrhal, Bernd David, Konstantins Jefimovs, Zhentian Wang, Carolina Arboleda, Udo Van Stevendaal, Magda Marcon, Gad Singer, Thomas Koehler, Ewald Roessl, Rahel A. Kubik-Huch, Kristina Lång, Serafino Forte, Norbert Kuhn, University of Zurich, and Arboleda, Carolina
- Subjects
medicine.medical_specialty ,610 Medicine & health ,Context (language use) ,Mammography ,Phase contrast ,Interferometry ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Breast cancer ,2741 Radiology, Nuclear Medicine and Imaging ,Medicine ,Radiology, Nuclear Medicine and imaging ,Medical physics ,Breast ,medicine.diagnostic_test ,10042 Clinic for Diagnostic and Interventional Radiology ,business.industry ,Attenuation ,Grating interferometer ,General Medicine ,medicine.disease ,3. Good health ,Visualization ,030220 oncology & carcinogenesis ,Radiology ,business ,Grating interferometry - Abstract
Objectives Grating-interferometry-based mammography (GIM) might facilitate breast cancer detection, as several research works have demonstrated in a pre-clinical setting, since it is able to provide attenuation, differential phase contrast, and scattering images simultaneously. In order to translate this technique to the clinics, it has to be adapted to cover a large field-of-view within a clinically acceptable exposure time and radiation dose. Methods We set up a grating interferometer that fits into a standard mammography system and fulfilled the aforementioned conditions. Here, we present the first mastectomy images acquired with this experimental device. Results and conclusion Our system performs at a mean glandular dose of 1.6 mGy for a 5-cm-thick, 18%-dense breast, and a field-of-view of 26 × 21 cm2. It seems to be well-suited as basis for a clinical-environment device. Further, dark-field signals seem to support an improved lesion visualization. Evidently, the effective impact of such indications must be evaluated and quantified within the context of a proper reader study. Key Points • Grating-interferometry-based mammography (GIM) might facilitate breast cancer detection, since it is sensitive to refraction and scattering and thus provides additional tissue information. • The most straightforward way to do grating-interferometry in the clinics is to modify a standard mammography device. • In a first approximation, the doses given with this technique seem to be similar to those of conventional mammography.
- Published
- 2019
- Full Text
- View/download PDF
42. Sensitivity-based optimization for the design of a grating interferometer for clinical X-ray phase contrast mammography
- Author
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Gerhard Martens, Carolina Arboleda, Matthias Bartels, Ewald Roessl, Zhentian Wang, Udo Van Stevendaal, Thomas Koehler, Pablo Villanueva-Perez, Marco Stampanoni, University of Zurich, and Arboleda, Carolina
- Subjects
Wave propagation ,Image quality ,Computer science ,Phase contrast microscopy ,Physics::Medical Physics ,Phase (waves) ,610 Medicine & health ,02 engineering and technology ,Grating ,3107 Atomic and Molecular Physics, and Optics ,030218 nuclear medicine & medical imaging ,law.invention ,170 Ethics ,03 medical and health sciences ,0302 clinical medicine ,Optics ,law ,medicine ,Mammography ,Figure of merit ,10237 Institute of Biomedical Engineering ,Sensitivity (control systems) ,medicine.diagnostic_test ,business.industry ,Phase-contrast imaging ,021001 nanoscience & nanotechnology ,Atomic and Molecular Physics, and Optics ,Interferometry ,0210 nano-technology ,business - Abstract
An X-ray grating interferometer (GI) suitable for clinical mammography must comply with quite strict dose, scanning time and geometry limitations, while being able to detect tumors, microcalcifications and other abnormalities. Such a design task is not straightforward, since obtaining optimal phase-contrast and dark-field signals with clinically compatible doses and geometrical constraints is remarkably challenging. In this work, we present a wave propagation based optimization that uses the phase and dark-field sensitivities as figures of merit. This method was used to calculate the optimal interferometer designs for a commercial mammography setup. Its accuracy was validated by measuring the visibility of polycarbonate samples of different thicknesses on a Talbot-Lau interferometer installed on this device and considering some of the most common grating imperfections to be able to reproduce the experimental values. The optimization method outcomes indicate that small grating pitches are required to boost sensitivity in such a constrained setup and that there is a different optimal scenario for each signal type.
- Published
- 2017
43. Elimination of bisphenol a and triclosan using the enzymatic system of autochthonous colombian forest fungi.
- Author
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Arboleda C, Cabana H, De Pril E, Jones JP, Jiménez GA, Mejía AI, Agathos SN, and Penninckx MJ
- Abstract
Bisphenol A (BPA) and triclosan (TCS) are known or suspected potential endocrine disrupting chemicals (EDCs) which may pose a risk to human health and have an environmental impact. Enzyme preparations containing mainly laccases, obtained from Ganoderma stipitatum and Lentinus swartzii, two autochthonous Colombian forest white rot fungi (WRF), previously identified as high enzyme producers, were used to remove BPA and TCS from aqueous solutions. A Box-Behnken factorial design showed that pH, temperature, and duration of treatment were significant model terms for the elimination of BPA and TCS. Our results demonstrated that these EDCs were extensively removed from 5 mg L(-1) solutions after a contact time of 6 hours. Ninety-four percent of TCS and 97.8% of BPA were removed with the enzyme solution from G. stipitatum; 83.2% of TCS and 88.2% of BPA were removed with the L. swartzii enzyme solution. After a 6-hour treatment with enzymes from G. stipitatum and L. swartzii, up to 90% of the estrogenic activity of BPA was lost, as shown by the yeast estrogen screen assay. 2,2-Azino-bis-(3-ethylthiazoline-6-sulfonate) (ABTS) was used as a mediator (laccase/mediator system) and significantly improved the laccase catalyzed elimination of BPA and TCS. The elimination of BPA in the absence of a mediator resulted in production of oligomers of molecular weights of 454, 680, and 906 amu as determined by mass spectra analysis. The elimination of TCS in the same conditions produced dimers, trimers, and tetramers of molecular weights of 574, 859, and 1146 amu. Ecotoxicological studies using Daphnia pulex to determine lethal concentration (LC50) showed an important reduction of the toxicity of BPA and TCS solutions after enzymatic treatments. Use of laccases emerges thus as a key alternative in the development of innovative wastewater treatment technologies. Moreover, the exploitation of local biodiversity appears as a potentially promising approach for identifying new efficient strains for biotechnological applications.
- Published
- 2012
- Full Text
- View/download PDF
44. P300-based brain computer interface experimental setup.
- Author
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Arboleda C, Garcia E, Posada A, and Torres R
- Subjects
- Reproducibility of Results, Sensitivity and Specificity, Algorithms, Brain physiology, Electroencephalography methods, Event-Related Potentials, P300 physiology, Pattern Recognition, Visual physiology, User-Computer Interface, Visual Cortex physiology
- Abstract
A Brain-Computer interface (BCI) is a communication system that enables the generation of a control signal from brain signals such as sensorymotor rhythms and evoked potentials; therefore, it constitutes a novel communication option for people with severe motor disabilities (such as Amyotrophic Lateral Sclerosis patients). This paper presents the development of a P300-based BCI. This prototype uses a homemade six-channel electroencephalograph for the acquisition of the signals, and a visual stimulation matrix; since this matrix contains letters of the alphabet as well as images associated to them, it permits word-writing and the elaboration of messages with the images. To process the signals the software BCI2000 and MATLAB 7.0 were used. The latter was used to program three linear translation algorithms (Stepwise Linear Discriminant Analysis, Lineal Discriminant Analysis and Least Squares) to convert the brain signals into communication signals. These algorithms had a classification accuracy of 90.73 %, 95.75 % and 89.45 % respectively, when using raw data; and of 90.78%, 49.48 % and 53.9 %, when data was previously common-average filtered. The experimental setup was tested in ten healthy volunteers; 5 of them got a 100% success, 1 a 90% success, 2 an around 70% success and 2 a 50% success, in the online free-spelling tests.
- Published
- 2009
- Full Text
- View/download PDF
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