583 research outputs found

    Species Specific Bacterial Spore Detection Using Lateral-Flow Immunoassay with DPA-Triggered Tb Luminescence

    Get PDF
    A method of detecting bacterial spores incorporates (1) A method of lateral-flow immunoassay in combination with (2) A method based on the luminescence of Tb3+ ions to which molecules of dipicolinic acid (DPA) released from the spores have become bound. The present combination of lateral-flow immunoassay and DPA-triggered Tb luminescence was developed as a superior alternative to a prior lateral-flow immunoassay method in which detection involves the visual observation and/or measurement of red light scattered from colloidal gold nanoparticles. The advantage of the present combination method is that it affords both (1) High selectivity for spores of the species of bacteria that one seeks to detect (a characteristic of lateral-flow immunoassay in general) and (2) Detection sensitivity much greater (by virtue of the use of DPA-triggered Tb luminescence instead of gold nanoparticles) than that of the prior lateral-flow immunoassay metho

    Hydrocyclone/Filter for Concentrating Biomarkers from Soil

    Get PDF
    The hydrocyclone-filtration extractor (HFE), now undergoing development, is a simple, robust apparatus for processing large amounts of soil to extract trace amounts of microorganisms, soluble organic compounds, and other biomarkers from soil and to concentrate the extracts in amounts sufficient to enable such traditional assays as cell culturing, deoxyribonucleic acid (DNA) analysis, and isotope analysis. Originally intended for incorporation into a suite of instruments for detecting signs of life on Mars, the HFE could also be used on Earth for similar purposes, including detecting trace amounts of biomarkers or chemical wastes in soils

    Method bacterial endospore quantification using lanthanide dipicolinate luminescence

    Get PDF
    A lanthanide is combined with a medium to be tested for endospores. The dipicolinic acid released from the endospores binds the lanthanides, which have distinctive emission (i.e., luminescence) spectra, and are detected using photoluminescence. The concentration of spores is determined by preparing a calibration curve generated from photoluminescence spectra of lanthanide complex mixed with spores of a known concentration. A lanthanide complex is used as the analysis reagent, and is comprised of lanthanide ions bound to multidentate ligands that increase the dipicolinic acid binding constant through a cooperative binding effect with respect to lanthanide chloride. The resulting combined effect of increasing the binding constant and eliminating coordinated water and multiple equilibria increase the sensitivity of the endospore assay by an estimated three to four orders of magnitude over prior art of endospore detection based on lanthanide luminescence

    Detection of bacterial spores with lanthanide-macrocycle binary complexes

    Get PDF
    The detection of bacterial spores via dipicolinate-triggered lanthanide luminescence has been improved in terms of detection limit, stability, and susceptibility to interferents by use of lanthanide−macrocycle binary complexes. Specifically, we compared the effectiveness of Sm, Eu, Tb, and Dy complexes with the macrocycle 1,4,7,10-tetraazacyclododecane-1,7-diacetate (DO2A) to the corresponding lanthanide aquo ions. The Ln(DO2A)^+ binary complexes bind dipicolinic acid (DPA), a major constituent of bacterial spores, with greater affinity and demonstrate significant improvement in bacterial spore detection. Of the four luminescent lanthanides studied, the terbium complex exhibits the greatest dipicolinate binding affinity (100-fold greater than Tb^(3+) alone, and 10-fold greater than other Ln(DO2A)^+ complexes) and highest quantum yield. Moreover, the inclusion of DO2A extends the pH range over which Tb−DPA coordination is stable, reduces the interference of calcium ions nearly 5-fold, and mitigates phosphate interference 1000-fold compared to free terbium alone. In addition, detection of Bacillus atrophaeus bacterial spores was improved by the use of Tb(DO2A)^+, yielding a 3-fold increase in the signal-to-noise ratio over Tb^(3+). Out of the eight cases investigated, the Tb(DO2A)^+ binary complex is best for the detection of bacterial spores

    Method and apparatus for distributed sensing of volatiles using a long period fiber grating sensor with modulated plastic coating for environmental monitoring

    Get PDF
    Optical time domain reflectometry caused by absorption of a volatile or analyte into the fiber optic cladding is used as an optical nose. The fiber optics (14) are covered with a gas permeable film (44) which is patterned to leave millimeter wide gas permeable notches (48a-48d). The notches contain a sensing polymer that responds to different gases by expanding or contracting

    Position discovery for a system of bouncing robots

    Get PDF
    International audienceA collection of n anonymous mobile robots is deployed on a unit-perimeter ring or a unit-length line segment. Every robot starts moving at constant speed, and bounces each time it meets any other robot or segment endpoint, changing its walk direction. We study the problem of position discovery, in which the task of each robot is to detect the presence and the initial positions of all other robots. The robots cannot communicate or perceive information about the environment in any way other than by bouncing nor they have control over their walks which are determined by their initial positions and their starting directions. Each robot has a clock allowing it to observe the times of its bounces. We give complete characterizations of all initial configurations for both the ring and the segment in which no position detection algorithm exists and we design optimal position detection algorithms for all feasible configurations

    Aplicación Web basada en redes neuronales para mejorar el control de asistencias con reconocimiento facial en la Institución Educativa Santísimo Sacramento de La Esperanza – Trujillo, 2023

    Get PDF
    El presente estudio, se enfocó en mejorar el control de asistencias en la Institución Educativa Santísimo Sacramento de la Esperanza - Trujillo, utilizando una aplicación web basada en redes neuronales, fue una investigación aplicada con diseño experimental puro, en la que se utilizó la observación directa para evaluar los indicadores de tiempo promedio para registrar asistencias, tiempo promedio para generar reportes de asistencia, nivel de exactitud de la información y tiempo promedio para la personalización de reportes, se estudiaron 30 registros del proceso de control de asistencia recogidos a través de un muestreo probabilístico aleatorio simple, y se procesaron los datos de los grupos control y experimental mediante la prueba de normalidad Shapiro-Wilk, con la ayuda del software Jamovi versión 2.3.28. La metodología de desarrollo del software seguida fue XP, que comprende las fases de planificación, diseño, desarrollo y pruebas, los resultados mostraron que, en el grupo experimental, el 53.33% del tiempo promedio para registrar asistencias, el 70% del mismo en la Posprueba, y el 90% en comparación con el grupo control, fueron inferiores al promedio, en cuanto al tiempo promedio para generar reportes, el 60% en el grupo experimental fue menor que su promedio, y el 90% y el 100% fueron inferiores a la meta y al promedio del grupo control, con respecto al nivel de exactitud de la información, el 80% en el grupo experimental superó su promedio y la meta, y el 96.67% excedió el promedio del grupo control, finalmente, para el tiempo promedio de personalización de reportes, el 60% en el grupo experimental fue inferior a su promedio, mientras que el 93.33% y el 100% fueron menores que la meta y el promedio del grupo control, así, se concluyó que la aplicación web basada en redes neuronales contribuyó a mejorar significativamente el control de asistencias en la institución educativa

    Sedimentología e Icnología de deltas fluvio-dominados afectados por descargas hiperpícnicas de la Formación Lajas (Jurásico Medio), Cuenca Neuquina, Argentina

    Get PDF
    En las áreas de Portada Covunco y Sierra de la Vaca Muerta, la Formación Lajas representa una sucesión deltaica fluvio-dominada integrada por depósitos de prodelta y frente deltaico, afectados por descargas hiperpícnicas y reelaborados por acción de oleaje (normal y de tormenta). Los depósitos de prodelta muestran una marcada geometría tabular con alternancia entre fangolitas y areniscas finas con abundante contenido de materia orgánica y desarrollo de una icnofacies de Cruziana empobrecida. Los depósitos de frente deltaico, integrados por fangolitas, areniscas finas a gruesas y conglomerados finos, presentan cuerpos de geometría tabular con desarrollo de las icnofacies de Skolithos y Glossifungites, esta última relacionada a la avulsión de lóbulos deltaicos. La progradación normal del sistema deltaico muestra intervalos estratigráficos integrados por cuerpos lenticulares y tabulares de espesor variable asignados a canales y lóbulos hiperpícnicos. Internamente estos depósitos presentan un pasaje transicional y recurrente entre diferentes estructuras sedimentarias con marcadas variaciones texturales, múltiples superficies de reactivación interna, y abundante contenido de materia orgánica. Los sistemas de canales hiperpícnicos muestran dimensiones y estilos de relleno diferentes. Al pie de las zonas de mayor gradiente, las descargas hiperpícnicas generaron canales mayores con relleno agradacional, mientras que en posiciones de menor gradiente del sistema, se desarrollaron canales de alta sinuosidad. En las zonas donde el flujo hiperpícnico perdió confinamiento se produjo la acumulación de sistemas de lóbulos hiperpícnicos. La presencia de niveles de conglomerados afectados por acción de oleaje coronando los arreglos, marcan los planos de pausa en la sedimentación, en los cuales se desarrollaron ventanas de colonización para el establecimiento de la fauna bentónica.There are few recognized examples of fluvial-dominated deltaic systems affected by hyperpycnal discharges. The development of predictive models in those systems are essential to understand the distribution of sedimentary facies and for determining the location of the main sandy bodies, which constitute the potential hidrocarbon reservoirs. In Portada Covunco and Sierra de la Vaca Muerta areas (Neuquén, Argentina), the Lajas Formation constitutes an excellent example of a deltaic fluvio-dominated succession consisting of prodelta and deltaic front deposits, affected by hyperpycnal discharges and reworked by wave action (storm and normal wave action). Prodelta deposits show a strongly tabular geometry alternating between mudstones and fine sandstones with abundant organic matter and development of an impoverished Cruziana ichnofacies. Deltaic-front deposits are integrated by mudstones, fine to coarse sandstones and fine conglomerates showing tabular geometries and development of the Skolithos and Glossifungites ichnofacies, the later related to deltaic lobe avulsión. Normal progradation of this deltaic system shows stratigraphic intervals consisting of tabular and lenticular bodies of variable thicknesses assigned to hyperpycnal-channel and lobe systems. Internally, these deposits show transitional and recurrent passages between different sedimentary structures with marked textural variations, multiple internal reactivation surfaces and abundant organic matter content. Hyperpycnal channels systems have different dimensions and fill patterns. At the foot of the areas with the greatest gradients, hyperpycnal discharges produced mayor channels with aggradational fill, whereas in areas with lower gradients, high sinuosity channels developed. Hyperpycnal lobes were accumulated in areas where hyperpycnal flows lost confinement. The presence of conglomeratic levels affected by wave action on top of the lobe deposits indicates pauses in sedimentation during which colonization windows could develope, allowing the establishment of the benthic fauna.Fil: Canale, Nerina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Negro. Sede Alto Valle. Instituto de Investigaciones en Paleobiología y Geología; ArgentinaFil: Ponce, Juan Jose. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Negro. Sede Alto Valle. Instituto de Investigaciones en Paleobiología y Geología; ArgentinaFil: Carmona, Noelia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Negro. Sede Alto Valle. Instituto de Investigaciones en Paleobiología y Geología; ArgentinaFil: Drittanti, Daniel. Universidad Nacional del Sur; ArgentinaFil: Olivera, Daniela Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Geológico del Sur. Universidad Nacional del Sur. Departamento de Geología. Instituto Geológico del Sur; ArgentinaFil: Martinez, Marcelo Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Geológico del Sur. Universidad Nacional del Sur. Departamento de Geología. Instituto Geológico del Sur; ArgentinaFil: Bournod, Constanza Naimé. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Geológico del Sur. Universidad Nacional del Sur. Departamento de Geología. Instituto Geológico del Sur; Argentin
    corecore