Disposable electrochromic polyaniline sensor based on a redox response using a conventional camera: A first approach to handheld analysis

We present a disposable optical sensor for Ascorbic Acid (AA). It uses a polyaniline based electrochromic sensing film that undergoes a color change when exposed to solutions of ascorbic acid at pH 3.0. The color is monitored by a conventional digital camera working with the hue (H) color coordinate. The electrochromic film was deposited on an Indium Tin Oxide (ITO) electrode by cyclic voltammetry and then characterized by atomic force microscopy, electrochemical and spectroscopic techniques. An estimation of the initial rate of H, as ΔH/Δt, is used as the analytical parameter and resulted in the following logarithmic relationship: ΔH/Δt = 0.029 log[AA] + 0.14, with a limit of detection of 17 μM. The relative standard deviation when using the same membrane 5 times was 7.4% for the blank, and 2.6% (for n = 3) on exposure to ascorbic acid in 160 μM concentration. The sensor is disposable and its applicability to pharmaceutical analysis was demonstrated. This configuration can be extended for future handheld configurations.

Molecularly imprinted silica films prepared by electroassisted deposition for the selective detection of dopamine

Dopamine (DA) can be detected by electrochemical oxidation in conventional electrodes. However, the presence of other oxidizable species (interferents) usually present in physiological fluids at high concentrations (like ascorbic acid) makes very difficult its electrochemical detection. In the present work, glassy carbon electrodes have been modified with molecularly imprinted silica (MIS) films prepared by electroassisted deposition of sol–gel precursors. The production of MIS films was performed by adding the template molecule (DA) to the precursor sol. The molecular impression of silica was assessed showing a high coherency allowing a filtering capacity in the molecular scale. The MIS-modified electrodes present a high selectivity for the detection of DA in neutral or acidic solutions. The MIS-modified electrodes allow the amperometric determination of dopamine in solutions containing ascorbic acid with molar ratios lower than 1:50,000.

Método POGIL para el Aprendizaje Cooperativo en Ciencias: Aplicación a la asignatura “Oceanografía Química”

Se muestra un método de aprendizaje cooperativo para una asignatura del Grado de Ciencias del Mar donde se aplica el método POGIL (Process-Oriented Guided Inquiry Learning). Los estudiantes aprenden los temas del curso siguiendo el ciclo del aprendizaje. En cada actividad se muestra un experimento o caso de estudio y se realizan preguntas para guiar a la comprensión del fenómeno observado. Tras la discusión y adquisición de los nuevos conceptos se formulan ejercicios para la aplicación de los mismos. Los grupos aprenden de forma autónoma pero el diseño de la actividad, menos libre que en métodos de aprendizaje similares (como el Aprendizaje Basado en Problemas) asegura la consecución de las competencias de conocimiento al final de la actividad. Se desarrollan además competencias genéricas: trabajo en equipo, comunicación efectiva y aprendizaje autónomo, entre otras. Se muestra un ejemplo de asignatura casi completamente desarrollada con este formato durante los 3 últimos cursos académicos. Se han realizado encuestas entre los alumnos con el fin de valorar el método educativo observándose que los alumnos se sienten más comprometidos con la asignatura y que tienen una mejor compresión de conceptos de química con este método que con clases tradicionales.

FISICO: Fast Image SegmentatIon COrrection.

BACKGROUND AND PURPOSE In clinical diagnosis, medical image segmentation plays a key role in the analysis of pathological regions. Despite advances in automatic and semi-automatic segmentation techniques, time-effective correction tools are commonly needed to improve segmentation results. Therefore, these tools must provide faster corrections with a lower number of interactions, and a user-independent solution to reduce the time frame between image acquisition and diagnosis. METHODS We present a new interactive method for correcting image segmentations. Our method provides 3D shape corrections through 2D interactions. This approach enables an intuitive and natural corrections of 3D segmentation results. The developed method has been implemented into a software tool and has been evaluated for the task of lumbar muscle and knee joint segmentations from MR images. RESULTS Experimental results show that full segmentation corrections could be performed within an average correction time of 5.5±3.3 minutes and an average of 56.5±33.1 user interactions, while maintaining the quality of the final segmentation result within an average Dice coefficient of 0.92±0.02 for both anatomies. In addition, for users with different levels of expertise, our method yields a correction time and number of interaction decrease from 38±19.2 minutes to 6.4±4.3 minutes, and 339±157.1 to 67.7±39.6 interactions, respectively.

"Lira libre" /

Poems.

Miserias humanas.

Mode of access: Internet.

Obras completas.

Mode of access: Internet.

Veladas del Ateneo.

Baldomero Lillo. Sub-sole.--Víctor Domingo Silva. El ladrón de flores.--Augusto Halmar. Via-Crucis.--Manuel Magallanes Moure. La carreta.--Amanda Labarca Hubertson. La torre de Santa Ireneia.--Samuel A. Lillo. La escuela de antaño.--Guillermo Labarca Hubertson. El pantano.--Augusto Winter. La fuga de los cisnes.--Federico Gana. La maiga.--Carlos Pezoa Veliz. Pancho i Tomás.--Emilio Lillo. El bueimuerto.--Antonio Bórquez Solar. La oración del huerto.--Paulino Alfonso. Impresiones de Versalles.--Max. Jara. El agua.--Ernesto Montenegro. La gran ciudad.--Rafael Maluenda. Animae facies.--Carlos R. Mondaca. Evanjelio.

Naturaleza y división de la pena

Mode of access: Internet.

Flores del cristianismo; ramillete.

Poems.

Anales de la Universidad de Chile ...

Ser. 2 in two parts: [pt. 1] Articulos científicos i literarios, and [pt. 2] Boletin de instrucción pública secundaria i superior (running title: Boletín de instrucción pública; v. 6?-8? Boletin del Consejo Universitario).

Historia jeneral de la República de Chile desde su independencia hasta nuestros dias ...

Vol. 1-4 pub. by J. S. Valenzuela; v. 5 by R. Jover.

Para secretarios de señores, y todo genero : nueuo estilo y formulario de escriuir cartas missiuas y responder a ellas ... /

Mode of access: Internet.

Istoria della vita, martirio, e prodigj del B. Giovanni Nepomuceno, canonico della S. Chiesa Metropolitana di Praga .. /

Triduo al glorioso martire S. Giovanni Nepomuceno ([6], 24 p.) con portada propia, a dos tintas y Del prodigio continuo della lingua di questo glorioso martire ([4] p.)

De la naturaleza de la enagenacion mental : Discurso pronunciado /

Tesis doctoral Univ. Central, 1854.