Fabry-Perot micro-structured polymer optical fibre sensors for opto-acoustic endoscopy

Opto-Acoustic Endoscopy (OAE) requires sensors with a high sensitivity and small physical dimensions in order to facilitate integration into an endoscope of less than 1mm in diameter. We present fibre Bragg grating (FBG) and Fabry- Perot intrinsic fibre sensors for ultrasound detection. We present a structure profile characterisation setup to analyse tune the fibre sensors in preparation for ultrasonic detection. We evaluate the suitability of the different structures and grating parameters for ultrasonic sensing. By analysing the prepared gratings, we enable the optimisation of the profile and a simplification of the detection regime for an optimal interferometric OAE configuration.

Polymer optical fibre sensors for endoscopic optoacoustic imaging

Opto-acoustic imaging (OAI) shows particular promise for in-vivo biomedical diagnostics. Its applications include cardiovascular, gastrointestinal and urogenital systems imaging. Opto-acoustic endoscopy (OAE) allows the imaging of body parts through cavities permitting entry. The critical parameter is the physical size of the device, allowing compatibility with current technology, while governing flexibility of the distal end of the endoscope based on the needs of the sensor. Polymer optical fibre (POF) presents a novel approach for endoscopic applications and has been positively discussed and compared in existing publications. A great advantage can be obtained for endoscopy due to a small size and array potential to provide discrete imaging speed improvements. Optical fibre exhibits numerous advantages over conventional piezo-electric transducers, such as immunity from electromagnetic interference and a higher resolution at small sizes. Furthermore, micro structured polymer optical fibres offer over 12 times the sensitivity of silica fibre. We present a polymer fibre Bragg grating ultrasound detector with a core diameter of 125 microns. We discuss the ultrasonic signals received and draw conclusions on the opportunities and challenges of applying this technology in biomedical applications.

A compact polymer optical fibre ultrasound detector

Polymer optical fibre (POF) is a relatively new and novel technology that presents an innovative approach for ultrasonic endoscopic applications. Currently, piezo electric transducers are the typical detectors of choice, albeit possessing a limited bandwidth due to their resonant nature and a sensitivity that decreases proportionally to their size. Optical fibres provide immunity from electromagnetic interference and POF in particular boasts more suitable physical characteristics than silica optical fibre. The most important of these are lower acoustic impedance, a reduced Young's Modulus and a higher acoustic sensitivity than single-mode silica fibre at both 1 MHz and 10 MHz. POF therefore offers an interesting alternative to existing technology. Intrinsic fibre structures such as Bragg gratings and Fabry-Perot cavities may be inscribed into the fibre core using UV lasers. These gratings are a modulation of the refractive index of the fibre core and provide the advantages of high reflectivity, customisable bandwidth and point detection. We present a compact in fibre ultrasonic point detector based upon a POF Bragg grating (POFBG) sensor. We demonstrate that the detector is capable of leaving a laboratory environment by using connectorised fibre sensors and make a case for endoscopic ultrasonic detection through use of a mounting structure that better mimics the environment of an endoscopic probe. We measure the effects of water immersion upon POFBGs and analyse the ultrasonic response for 1, 5 and 10 MHz.

Bilirubin Present in Diverse Angiosperms

Background and aims: Bilirubin is an orange-yellow tetrapyrrole produced from the breakdown of heme by mammals and some other vertebrates. Plants, algae, and cyanobacteria synthesize molecules similar to bilirubin, including the protein-bound bilins and phytochromobilin which harvest or sense light. Recently, we discovered bilirubin in the arils of Strelitzia nicolai, the White Bird of Paradise Tree, which was the first example of this molecule in a higher plant. Subsequently, we identified bilirubin in both the arils and flowers of Strelitzia reginae, the Bird of Paradise Flower. In the arils of both species, bilirubin is present as the primary pigment, and thus functions to produce color. Previously, no tetrapyrroles were known to generate display color in plants. We were therefore interested in determining whether bilirubin is broadly distributed in the plant kingdom, and whether it contributes to color in other species.

Animal pigment bilirubin discovered in plants

The bile pigment bilirubin-IXα is the degradative product of heme, distributed among mammals and some other vertebrates. It can be recognized as the pigment responsible for the yellow color of jaundice and healing bruises. In this paper we present the first example of the isolation of bilirubin in plants. The compound was isolated from the brilliant orange-colored arils of Strelitzia nicolai, the white bird of paradise tree, and characterized by HPLC−ESMS, UV−visible, 1H NMR, and 13C NMR spectroscopy, as well as comparison with an authentic standard. This discovery indicates that plant cyclic tetrapyrroles may undergo degradation by a previously unknown pathway. Preliminary analyses of related plants, including S. reginae, the bird of paradise, also revealed bilirubin in the arils and flowers, indicating that the occurrence of bilirubin is not limited to a single species or tissue type.

Expanding guitar production techniques: Building the Guitar Application Toolkit (GATK)

The purpose of this thesis was to build the Guitar Application ToolKit (GATK), a series of applications used to expand the sonic capabilities of the acoustic/electric stereo guitar. Furthermore, the goal of the GATK was to extend improvisational capabilities and the compositional techniques generated by this innovative instrument. ^ During the GATK creation process, the current production guitar techniques and overall sonic result were enhanced by planning and implementing a personalized electro-acoustic performance set up, designing custom-made performance interfaces, creating interactive compositional strategies, crafting non-standardized sounds, and controlling various music parameters in real-time using the Max/MSP programming environment. ^ This was the fast thesis project of its kind. It is expected that this thesis will be useful as a reference paper for electronic musicians and music technology students; as a product demonstration for companies that manufacture the relevant software; and as a personal portfolio for future technology related jobs. ^

The Sesquiterpene Lactone Dehydroleucodine Triggers Senescence and Apoptosis in Association with Accumulation of DNA Damage Markers

Sesquiterpene lactones (SLs) are plant-derived compounds that display anti-cancer effects. Some SLs derivatives have a marked killing effect on cancer cells and have therefore reached clinical trials. Little is known regarding the mechanism of action of SLs. We studied the responses of human cancer cells exposed to various concentrations of dehydroleucodine (DhL), a SL of the guaianolide group isolated and purified from Artemisia douglasiana (Besser), a medicinal herb that is commonly used in Argentina. We demonstrate for the first time that treatment of cancer cells with DhL, promotes the accumulation of DNA damage markers such as phosphorylation of ATM and focal organization of γH2AX and 53BP1. This accumulation triggers cell senescence or apoptosis depending on the concentration of the DhL delivered to cells. Transient DhL treatment also induces marked accumulation of senescent cells. Our findings help elucidate the mechanism whereby DhL triggers cell cycle arrest and cell death and provide a basis for further exploration of the effects of DhL in in vivo cancer treatment models.

Post-revolutionary post-modernism: Central American detective fiction by the turn of the 21st century

Contemporary Central American fiction has become a vital project of revision of the tragic events and the social conditions in the recent history of the countries from which they emerge. The literary projects of Sergio Ramirez (Nicaragua), Dante Liano (Guatemala), Horacio Castellanos Moya (El Salvador), and Ramon Fonseca Mora (Panama), are representative of the latest trends in Central American narrative. These trends conform to a new literary paradigm that consists of an amalgam of styles and discourses, which combine the testimonial, the historical, and the political with the mystery and suspense of noir thrillers. Contemporary Central American noir narrative depicts the persistent war against social injustice, violence, criminal activities, as well as the new technological advances and economic challenges of the post-war neo-liberal order that still prevails throughout the region. ^ Drawing on postmodernism theory proposed by Ihab Hassan, Linda Hutcheon and Brian MacHale, I argued that the new Central American literary paradigm exemplified by Sergio Ramirez's El cielo llora por mí, Dante Liano's El hombre de Montserrat, Horacio Castellanos Moya's El arma en el hombre and La diabla en el espejo , and Ramon Fonseca Mora's El desenterrador, are highly structured novels that display the characteristic marks of postmodern cultural expression through their ambivalence, which results from the coexistence of multiple styles and conflicting ideologies and narrative trends. The novels analyzed in this dissertation make use of a noir sensitivity in which corruption, decay and disillusionment are at their core to portray the events that shaped the modern history of the countries from which they emerge. The revolutionary armed struggle, the state of terror imposed by military regimes and the fight against drug trafficking and organized crime, are among the major themes of these contemporary works of fiction, which I have categorized as perfect examples of the post-revolutionary post-modernism Central American detective fiction at the turn of the 21st century.^

Forma y contenido en la escultura de Francisco Toledo

La presente tesis pretende sacar a la luz una obra escultórica excepcional y desconocida, que representa lo mejor de la figuración española del siglo XX, realizada por Francisco Toledo Sánchez. El doble componente, docente y artístico, otorgó a nuestro escultor la suficiente independencia económica como para que sus obras fueran del todo libres y toda la dedicación temporal necesaria para posibilitarle unos desarrollos y acabados únicos, pero al tiempo una cierta despreocupación por su exposición y destino final, lo que pensamos pudo ser una de las causas que propició el desconocimiento y descatalogación de su obra. El primer y principal objetivo de esta tesis es, por tanto, dar a conocer esta magnífica obra escultórica (actualmente desconocida) de Francisco Toledo, analizarla y catalogarla para ofrecer un documento gráfico significativo y didáctico de su trayectoria artística, sintetizada en su obra y recogida en fotografías realizadas por el propio doctorando o, en otros casos, cedidas por el propio escultor. El fallecimiento de Francisco Toledo en 2004, convierte este objetivo en un deber de justicia hacia su figura y una reivindicación acerca del lugar que esta debe ocupar en la Historia del Arte, más concretamente en la Historia de la Escultura. Todos los que fuimos sus alumnos y compañeros, sabemos de la inmensidad de su maestría, pero sin una investigación rigurosa que permita la publicación y exposición de su obra, esta quedaría diluida y con peligro de desaparición. De hecho hemos podido comprobar en esta investigación como, a pesar de los pocos años transcurridos desde su muerte, existen numerosas atribuciones falsas, pérdidas y en el mejor de los casos anonimatos en la atribución de su obra. Esta tesis esta fundamentada en el documento vital de Francisco Toledo a través de numerosos encuentros y entrevistas que jalonando sus recuerdos biográficos recogen su ideario, proceso y procedimiento de la creación de su obra escultórica vista desde la perspectiva de otro escultor y docente...

Étude de l'association entre la fréquence cardiaque au repos et la survie

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Étude de l'association entre la fréquence cardiaque au repos et la survie

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Trabajo de campo en el aula. Reflexiones sobre la experiencia de las clases prácticas de la cátedra Metodología de la Investigación Social II (Métodos y técnicas cualitativas)

Fil: Aguiar, Diego. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

La construcción de lo transcendente en el catolicismo integral y en el catolicismo justicialista

La ponencia comparará la construcción de lo trascendente en el sujeto religioso a partir del catolicismo integral y militante del Vicario General de la Armada Argentina (desde 1926 hasta 1940) Monseñor Dionisio Napal y el catolicismo penetrado por el justicialismo cristiano del Padre Hernán Benítez, jesuita y confesor de Eva Duarte de Perón. Ya no será la Iglesia la mediadora en la construcción de lo trascendente, como predica Dionisio Napal en su vasta producción literaria sino que la tercera posición del justicialismo cristiano, desarrollada por Hernán Benítez, y "el pueblo" serán los elementos constitutivos de esta construcción de lo trascendente. Es por ello que para Hernán Benítez la verdadera Iglesia es aquella que se "obreriza", se hace "pueblo", compartiendo "con" y no tan solo "junto a" las limitaciones materiales y las virtudes antes citadas. Hay una crítica profunda en Benítez a la Iglesia de Napal, jerárquica, preocupada caritativamente por los pobres, organizadora de los Círculos Obreros pero sin tomar acciones de fondo para revertir las razones socioestructurales de las desigualdades. Lo trascendente en Napal es espiritual, separando la Iglesia terrenal y militante, de la Iglesia victoriosa espiritual, reivindicada en un futuro escatológico por Dios, mientras que en Benítez, la trascendencia es histórica, política y no hay una construcción dicotómica, la Iglesia espiritual e histórica es una sola. En Napal, el católico es el depositario de lo eterno y la Iglesia Católica proporciona el fundamento dogmático de la construcción de lo trascendente, en cambio en Benítez, el pueblo es el depositario de lo eterno y el justicialismo cristiano es el heredero e intérprete histórico de la prédica en los evangelios

El enfoque comparativo en la investigación en didáctica de la educación física : Objetos de saber y problemas de trasposición

El propósito de este trabajo es presentar las características del enfoque comparativo en la investigación en didáctica de la educación física, analizando el proceso de trasposición en el tratamiento didáctico de las prácticas motrices, señalando la relevancia que este enfoque tiene para los procesos de desarrollo curricular y de formación docente

Investigación y didáctica de la educación física : Tradiciones de un campo y orientación actual de los estudios

El propósito de este trabajo es describir el estado del arte en los últimos 50 años de investigación en el campo de la didáctica especial de la educación física, procurando adicionalmente incorporar en el análisis las tareas realizadas por el equipo de investigación dirigido por el autor en los últimos 10 años en la AEIEF /FAHCE/UNLP tratando de situar la orientación epistemológica actual de los estudios del equipo, particularmente el programa de investigación comparativa, o enfoque didáctico