Biomedical Engineering and Bioengineering Commons^™

Estudio De Prevalencia En Salud Visual En Una Población Escolar De Bogotá, Colombia, 2000, Clara Patricia Hernández Luna, Deisy Catalina Barrera Santos, Carolina Guiza Segura, Johanna Patricia Rodríguez Malagón, Walter Ernesto Ludeman, Sandra Paola Gómez Montaña

Ciencia y Tecnología para la Salud Visual y Ocular

Las deficiencias visuales en los escolares, pueden implicar problemas en el aprendizaje y retardo en el desarrollo psicosocial. Debido a la poca información sobre esta problemática en el Distrito, se realizo este estudio de tipo descriptivo, con el objeto de determinar la prevalencia de alteraciones oculares‐visuales, en una muestra de 1.250 niños de 5 a 14 años de establecimientos oficiales y privados en Bogotá. El 42% de los niños escolares presento algún grado de deficiencia en la AV (20/25 o menor). De deficiencia disminuye a medida que aumenta la edad. En cuanto a los defectos refractivos se presentaron: hipermetropía (59.2%), …

Omega 3 Y Su Acción Terapéutica En El Síndrome De Ojo Seco, Neida Esperanza Ronderos Escamilla

Ciencia y Tecnología para la Salud Visual y Ocular

Los ácidos grasos esenciales Omega 3 y Omega 6 tienen efectos competitivos e inhibitorios en el organismo. Mientras el primero actúa como antiinflamorio, el segundo tiene un derivado clave en la cascada inflamatoria: el acido araquidonico. Por tanto se plantea el omega 3 como terapéutico en el proceso inflamatorio del Síndrome de Ojo Seco.

Los Hábitos De Los Directivos De Alto Rendimiento, Ingrid Astrid Jiménez Barbosa

Ciencia y Tecnología para la Salud Visual y Ocular

Los directivos de cualquier organización se encuentran constantemente en la búsqueda de alguna teoría, tendencia o forma de dirigirse a ellos mismos, así como a la Organización que lideran, de la manera más efectiva. Los directivos que alcanzan un rendimiento elevado crean situaciones, o permiten que se les conduzcan a ellas, en las que identifican sus fuerzas. Siempre están en el lugar y en el momento adecuado y además son capaces de eludir el fracaso. Reconocen sus capacidades claves del éxito y con ello demuestran que hay un mundo de acción y de gestión más allá de la estrategia. En …

Compact Supercell Method Based On Opposite Parity For Bragg Fibers, Wang Zhi, Ren Guobin, Lou Shuquin, Liang Weijun, Shangping Guo

Electrical & Computer Engineering Faculty Publications

The supercell- based orthonormal basis method is proposed to investigate the modal properties of the Bragg fibers. A square lattice is constructed by the whole Bragg fiber which is considered a supercell, and the periodical dielectric structure of the square lattice is decomposed using periodic functions (cosine). The modal electric field is expanded as the sum of the orthonormal set of Hermite-Gaussian basis functions based on the opposite parity of the transverse electric field. The propagation characteristics of Bragg fibers can be obtained after recasting the wave equation into an eigenvalue system. This method is implemented with very high efficiency …

Influence Of Sorghum Wax, Glycerin, And Sorbitol On Physical Properties Of Soy Protein Isolate Films, Ki Myong Kim, David B. Marx, Curtis Weller, Milford Hanna

Biological Systems Engineering: Papers and Publications

Sorghum wax, sorbitol, glycerin, and soy protein isolate (SPI) composite films were prepared. Effects of sorghum wax, sorbitol, and glycerin concentrations on various films were evaluated using response surface methodology. All independent variables significantly (P < 0.05) affected film water vapor permeability (WVP), tensile strength (TS), elongation at break (E), total color difference, and total soluble matter (TSM). Increasing the sorghum wax concentration decreased WVP and E. As sorbitol content increased in the composite films, WVP and TS increased. Sorbitol had a critical point of 2–5 g/5 g SPI for low values of TSM. The addition of sorbitol contributed more to the properties of the film than did glycerin.

Curva Normal De Sensibilidad Al Contraste (Fact) En Niños Entre 6 Y 12 Años En El Instituto De Investigaciones Optométricas, Yolanda López Aguirre

Ciencia y Tecnología para la Salud Visual y Ocular

El test de sensibilidad al contraste (FACT) es util en la detección y diagnostico de diversas patologías oculares pero su uso se ha limitado mucho en niños. El objetivo de este estudio fue construir la curva con el rango de normalidad para el mencionado Test, para frecuencias especiales de 1.5, 3.0, 6.0, 12.0 y 18.0, para niños de 6 a 12 años que consultan el Instituto de Investigaciones Optométricas de la Universidad de La Salle. Fue un estudio descriptivo para estandarización de un test, con una muestra de 58 niños (nivel de confianza 95%, error muestral del 5%), mediante muestreo …

Estado Refractivo En Niños Menores De Un Año De Edad, Marta Bermúdez Ruiz

Ciencia y Tecnología para la Salud Visual y Ocular

Describe el estado refractivo en niños menores de un año de edad. Los niños examinados proceden de la población pediátrica del hospital de Tunjuelito‐ Clínica El Carmen, que asisten al “Programa de Crecimiento y Desarrollo”. La refracción fue determinada mediante la técnica de retinoscopia dinámica. Los estados refractivos encontrados más comúnmente fueron: Astigmatismo (77.5% OD, 73.5 OI: con la regla 100% OD 97.4% OI) del tipo hipermétrope compuesto y mixto. El componente esférico positivo y negativo encontrado en el ojo derecho oscilo entre 0.25 y 1.50 dioptrías, en el ojo izquierdo y el componente esférico positivo fluctuó entre 0.25 y …

Perfil Microbiológico De Pacientes Con Patología Infecciosa Del Segmento Anterior, Patricia Hernández Rodríguez, Gladys M. Quintero

Ciencia y Tecnología para la Salud Visual y Ocular

En esta investigación fueron evaluados 286 pacientes con patología infecciosa del segmento anterior y mediante estudio microbiológico se identificaron las bacterias asociadas con la infección. En 286 cultivos bacteriológicos realizados se obtuvieron 177 aislamientos, encontrándose un 73.45% de flora gran positiva siendo las especies más frecuentes S. Epidermidis 48.46%, S. Aureus (35.38%), S.Pneumoniae (4.61%) y Corynebacterium SP. (2.31%). El 26.55% correspondía a bacilos gran negativos de los cuales el 74.47% son enterobacterias y el 25.53% microorganismos no fermentados. El mayor porcentaje de aislamientos fue realizado en pacientes con conjuntivitis bacteriana, blefaritis bacteriana, conjuntivitis inespecífica y blefaritis inespecífica.

Técnicas Moleculares: Un Avance En El Diagnóstico Y Conocimiento De Patología Oculares, Patricia Hernández Rodríguez

Ciencia y Tecnología para la Salud Visual y Ocular

Hace 40 años era imposible pensar en la manipulación genética; pero la marcha incensante que permitió la comprensión de algunos aspectos de la regulación génica en condiciones normales y patológicas, ha generado un amplio campo investigativo. El descubrimiento de la estructura doble del DNA, ls purificación del DNA y el conocimiento de la actividad que presenta ciertas enzimas (endonucleasas de restricción) sobre los ácidos nucleicos, puso en el escenario científico las herramientas necesarias para comprender ciertos procesos fisiológicos. Son muchas las disciplinas que han utilizado las tecnologías moleculares como puente para ampliar el conocimiento y sin duda, en las ciencias …

Los Términos Científicos Más Usados En Optometría, Pilar Alcazar Orduz

Ciencia y Tecnología para la Salud Visual y Ocular

Cada ciencia tiene una terminología propia y lo significados de ella se desprenden no pueden aplicarse a otra indistintamente. Por esto me voy a ceñir a las palabras referentes a optometría y al significado que en esta ciencia tiene; resulta indispensable para un estudiante saber la etimología del vocabulario técnico de su profesión, por ser universal, base de los fundamentos científicos. Su comprensión y uso facilitan una comunicación en un lenguaje adecuado y preciso. Explicare los términos técnicos mas usuales y definiré otras palabras según se refiera a ciertas características que entran en el estudio general de la optometría.

Molecular Dynamics Of Soy-Protein Isolate Films Plasticized By Water And Glycerol, S.-G. Choi, K. M. Kim, Milford Hanna, Curtis L. Weller, W. L. Kerr

Biological Systems Engineering: Papers and Publications

The effects of water and glycerol on the molecular mobility of a soy-protein isolate (SPI)-based film were investigated using ¹H nuclear magnetic resonance (NMR). SPI-films were prepared with different glycerol contents and equilibrated to various levels of water activity (a_w). The distributed transverse relaxation of film samples showed 2 distinct components: a solid-like fraction (T_2s*) and a liquid-like fraction (T_2m*). The peak T_2s* values of films with lower glycerol concentration were more sensitive to variation in aw. As a_w increased, the change of solid-like to liquid-like fraction was observed in …

Sensitivity To Hand Path Curvature During Reaching, Kyle P. Lillis, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

People optimize reaching to make straight and smooth movements. We performed experiments characterizing human sensitivity to hand path deviations from a straight reach. Vision of the arm was blocked. Subjects either moved the hand along paths of constrained curvature, or a robot moved the relaxed limb along similar trajectories (active and passive conditions, respectively). Subjects responded after each trial whether or not they thought the movement curved convex right. In a series of three experiments, we tested the effects of modifying visual feedback of hand position to suppress curvature, isotonic muscle activation, and a distracter task on subjects ability to …

Mechanisms Of Volatile Anesthetic-Induced Myocardial Protection, Lynda M. Ludwig, Judy R. Kersten, Katsuya Tanaka, Weidong Gu, John F. Ladisa, David C. Warltier, Paul S. Pagel

Biomedical Engineering Faculty Research and Publications

Volatile anesthetics protect myocardium against reversible and irreversible ischemic injury. Experimental evidence from several in vitro and in vivo animal models demonstrates that volatile agents enhance the recovery of stunned myocardium and reduce the size of myocardial infarction after brief or prolonged coronary artery occlusion and reperfusion, respectively. This protective effect persists after the anesthetic has been discontinued, a phenomenon known as anesthetic-induced preconditioning (APC). Recent clinical data also demonstrates evidence of APC in patients during cardiac surgery. Thus, administration of volatile anesthetics may represent a novel therapeutic approach that reduces morbidity and mortality associated with perioperative myocardial ischemia and …

Three-Dimensional Reconstruction Algorithm For A Reverse-Geometry Volumetric Ct System With A Large-Array Scanned Source, Taly Gilat Schmidt, Rebecca Fahrig, Norbert J. Pelc

Biomedical Engineering Faculty Research and Publications

We have proposed a CT system design to rapidly produce volumetric images with negligible cone beam artifacts. The investigated system uses a large array scanned source with a smaller array of fast detectors. The x-ray source is electronically steered across a 2D target every few milliseconds as the system rotates. The proposed reconstruction algorithm for this system is a modified 3D filtered backprojection method. The data are rebinned into 2D parallel ray projections, most of which are tilted with respect to the axis of rotation. Each projection is filtered with a 2D kernel and backprojected onto the desired image matrix. …

Clinical Blood Flow Quantification With Segmented K-Space Magnetic Resonance Phase Velocity Mapping, George P. Chatzimavroudis, Haosen Zhang, Sandra S. Halliburton, James R. Moore, Orlando Simonetti, Paulo R. Schvartzman, Arthur E. Stillman, Richard D. White

Chemical & Biomedical Engineering Faculty Publications

To evaluate the accuracy of segmented k-space magnetic resonance phase velocity mapping (PVM) in quantifying aortic blood flow from through-plane velocity measurements.

Two segmented PVM schemes were evaluated, one with seven lines per segment (seg-7) and one with nine lines per segment (seg-9), in twenty patients with cardiovascular disease. A non-segmented (non-seg) PVM acquisition was also performed to provide the reference data.

There was agreement between the aortic flow curves acquired with segmented and non-segmented PVM. The calculated systolic and total flow volume per cycle from the seg-7 and the seg-9 scans correlated and agreed with the flow volumes from …

The Economic Impacts Of Various Public-Policy Scenarios For Methane Recovery On Dairy Farms, Richard Stowell, Chris G. Henry

Department of Biological Systems Engineering: Conference Presentations and White Papers

The feasibility of anaerobic digesters for dairy and swine operations in Nebraska was evaluated using EPA’s Ag Star software program Farmworks 2.0 (1997) and local values for farm energy costs, mainly electricity. Four incentive programs were considered that would subsidize anaerobic digestion. Installation of a digester system is a significant investment that is currently very difficult to justify economically to Nebraska producers based upon consideration of readily quantifiable income and expenses, regardless of farm size. Larger dairy operations looking to invest in this technology would benefit most from a tax credit and/or subsidized electricity sales, policies that relate directly to …

Application And Performance Of Constructed Wetlands For Runoff From Small Open Lots, C. G. Henry, J. P. Harner Iii, T. D. Strahm, M. A. Reynolds

Department of Biological Systems Engineering: Conference Presentations and White Papers

Vegetative systems have long been studied and evaluated as alternatives to conventional storage, treatment, and land application systems. This paper discusses the application of vegetative systems, primarily constructed wetlands, as a runoff treatment technology for small livestock operations. The approach used for two small dairies and one beef cattle feedlot is discussed. Cost data for these operations is included as well as nutrient reduction performance results from a three year sampling period for the KS Dairy.

Interaction Of Disparity And Accommodative Vergence, Michele Liu Kung

Theses

To fixate on a target that moves from far to near, changes in blur and disparity activate accommodation and disparity vergence. The goal of this study was to experimentally obtain eye movement data from four subjects, and analyze this data using through a new signal processing algorithm known as independent component analysis (ICA). Preliminary data suggest that three underlying neural subcomponents are present where the two components of disparity vergence initiate the movement and the accommodative portion is activated to facilitate the steady state portion of the response.

ICA was used as a blind source separation technique to analyze experimental …

Feasibility Of Radiographic Absorptiometry Of The Mandible As An Osteoporosis Screening Method, Julie A. Skipper

Browse all Theses and Dissertations

The purpose of this work was to develop and evaluate single- and dual-energy radiographic absorptiometry (RA) for the measurement of mandibular bone mineral density (BMD), using standard dental equipment, that would allow for inexpensive and widespread osteoporosis screening. Accurately measured x-ray tube spectra are important for validating the simulations used in the design of the method. A constrained least-squares deconvolution technique for reducing the detector-induced blurring of the energy spectrum was developed. Application of this analytic correction to spectra acquired with a NaI-photomultiplier detector improved the measured data by 20-60%. Implementation of the screening method is accomplished by simultaneously acquiring …

Cell And Organ Printing 2: Fusion Of Cell Aggregates In Three-Dimensional Gels, Thomas Boland, Vladimir Mironov, Anna Gutowska, Elisabeth Roth, Roger Markwald

Thomas Boland

We recently developed a cell printer (Wilson and Boland, 2003) that enables us to place cells in positions that mimic their respective positions in organs. However, this technology was limited to the printing of two-dimensional (2D) tissue constructs. Here we describe the use of thermosensitive gels to generate sequential layers for cell printing. The ability to drop cells on previously printed successive layers provides a real opportunity for the realization of three-dimensional (3D) organ printing. Organ printing will allow us to print complex 3D organs with computer-controlled, exact placing of different cell types, by a process that can be completed …

Cell And Organ Printing 1: Protein And Cell Printers, Cris Wilson, Thomas Boland

Thomas Boland

We have developed several devices for positioning organic molecules, molecular aggregates, cells, and single-cell organisms onto solid supports. These printers can create stable, functional protein arrays using an inexpensive technology. The cell printer allows us to create cell libraries as well as cellular assemblies that mimic their respective position in organs. The printers are derived from commercially available ink-jet printers that are modified to dispense protein or cell solutions instead of ink. We describe here the modifications to the print heads, and the printer hardware and software that enabled us to adapt the ink-jet printers for the manufacture of cell …

Characterization Of Patterned Self-Assembled Monolayers And Protein Arrays Generated By The Ink-Jet Method, Laura Pardo, Thomas Boland

Thomas Boland

Commercial ink-jet printers were used with little modification to deposit alkanethiols onto gold substrata and several proteins onto silica supports. The resulting patterns of alkanethiols form self-assembled layers comparable to those obtained by microcontact printing or solution adsorption. The method has been used successfully to create binary chemical gradients and patterns of tertiary functionality. The proteins form dense patterns on the substrates and seem to maintain their configuration as measured by their ability to bind their specific ligands. Four different proteins were printed simultaneously, allowing for positive and negative controls. This "drop-on-demand" printing method is an inexpensive, flexible alternative to …

Organ Printing: Computer Aided Jet Based 3d Tissue Engineering, Vladimir Mironov, Thomas Boland, Thomas Trusk, Gabor Forgacs, Roger Markwald

Thomas Boland

Tissue engineering technology promises to solve the organ transplantation crisis. However, assembly of vascularized 3D soft organs remains a big challenge. Organ printing, which we define as computer-aided, jet-based 3D tissue-engineering of living human organs, offers a possible solution. Organ printing involves three sequential steps: pre-processing or development of "blueprints" for organs; processing or actual organ printing; and postprocessing or organ conditioning and accelerated organ maturation. A cell printer that can print gels, single cells and cell aggregates has been developed. Layer-by-layer sequentially placed and solidified thin layers of a thermo-reversible gel could serve as "printing paper". Combination of an …

A Quantitative Approach To Studying Structures And Orientation At Self- Assembled Monolayer/Fluid Interfaces", Laura Pardo, Thomas Boland

Thomas Boland

Self-assembled monolayers (SAMs) have become a standard tool for exploring surface interactions. Although well characterized, SAMs are known to undergo structural and conformational changes in the presence of solution, yet the ability to quantify these changes remains an obstacle due to limited analytical techniques. In this study, we determine changes in structure and conformation of CH3, OH, and COOH terminated hexadecanethiols on gold in water by means of a new technique known as evanescence reflection spectroscopy. This FTIR application, in conjunction with a semiempirical formalism, is capable of providing both qualitative and quantitative understanding of the molecular structure and orientation …

Apparatus For Illuminating The Tip-Sample Interface Of An Atomic Force Microscope, Nancy Burnham, E Thoreson

Nancy A. Burnham

An apparatus for the delivery of radiation to the tip-sample interface of an atomic force microscope(AFM) is demonstrated. The pulsed light delivery system (PLDS) was fabricated to probe photoinduced conformational changes of molecules using an AFM. The system is 67 mm long, 59 mm wide, and 21 mm high, leaving clearance to mount the PLDS and a microscope slide coated with a thin film of photoactive molecules beneath the cantilever tip of a stand-alone AFM. The PLDS is coupled into a fiber pigtailed Nd:yttrium–aluminum–garnetfrequency doubled laser, operating at a wavelength of 532 nm. The radiation delivered to a sample through …