Browsing by Author "Parot Fernández, Vicente José"

Now showing 1 - 16 of 16
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    3D imaging techniques for improved colonoscopy.
    (2014) Durr, Nicholas J.; González, Germán; Parot Fernández, Vicente José
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    Application of the fractional Fourier transform to image reconstruction in MRI
    (2009) Parot Fernández, Vicente José; Irarrázaval Mena, Pablo; Pontificia Universidad Católica de Chile. Escuela de Ingeniería
    Para obtener Imágenes de Resonancia Magnética (MRI) de buena calidad, es necesario tener una buena homogeneidad espacial en el campo B0 de la región a observar. La homogeneidad de campo es difícil de lograr, particularmente para imanes de núcleo corto y campos altos. Cuando el ajuste fino pasivo o activo no es suficiente, o cuando la inhomogeneidad viene de diferencias en la susceptibilidad entre regiones adyacentes dentro de un objeto, hay varias técnicas de post\2013procesamiento para corregir las distorsiones. ´Estas técnicas no tienen un fundamento teórico sólido con la excepción de las relativas a términos lineales. Proponemos usar la Transformada Fraccionaria de Fourier (FrFT) para reconstruir señales MRI obtenidas en campos con desviaciones cuadráticas. La FrFT provee un marco teórico preciso para esto.
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    Compressed Hadamard microscopy for high-speed optically sectioned neuronal activity recordings
    (2019) Parot Fernández, Vicente José; Sing-Long C., Carlos A.; Adam, Yoav; Bohm, Urs L.; Fan, Linlin Z.; Cohen, Adam E.; Farhi, Samouil L.
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    Confocal 3D reflectance imaging through multimode fiber without wavefront shaping
    (2022) Lee, Szu-Yu; Parot Fernández, Vicente José; Bouma, Brett E.; Villiger, Martin
    Imaging through optical multimode fiber (MMF) has the potential to enable hair-thin endoscopes that reduce the invasiveness of imaging deep inside tissues and organs. Active wavefront shaping and fluorescent labeling have recently been exploited to overcome modal scrambling and enable MMF imaging. Here, we present a computational approach that circumvents the need for active wavefront control and exogenous fluorophores. We demonstrate the reconstruction of depth-gated confocal images through MMF using a raster-scanned, focused input illumination at the fiber proximal end. We show the compatibility of this approach with quantitative phase, dark-field, and polarimetric imaging. Computational imaging through MMF opens a new pathway for minimally invasive imaging in medical diagnosis and biological investigations. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement
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    Extended Kalman filter estimates the contour length of a protein in single molecule atomic force microscopy experiments.
    (2009) Parot Fernández, Vicente José; Kosuri, Pallav; Fernández, Julio M.
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    Feature space optimization for virtual chromoendoscopy augmented by topography.
    (2014) González, Germán; Parot Fernández, Vicente José; Lo, William; Vakoc, Benjamin J.; Durr, Nicholas J.
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    Genetically targeted all-optical electrophysiology with a transgenic cre-dependent optopatch mouse.
    (2016) Lou, Shan; Adam, Yoav; Weinstein, Eli N.; Williams, Erika; Williams, Katherine; Parot Fernández, Vicente José; Kavokine, Nikita; Liberles, Stephen; Madisen, Linda; Zeng, Hongkui; Cohen, Adam E.
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    Optogenetic control of Nodal signaling patterns
    (2024) McNamara, Harold M.; Jia, Bill Z.; Guyer, Alison; Parot Fernández, Vicente José; Dobbs, Caleb; Schier, Alexander F.; Cohen, Adam E.; Lord, Nathan D.
    A crucial step in early embryogenesis is the establishment of spatial patterns of signaling activity. Tools to perturb morphogen signals with high resolution in space and time can help reveal how embryonic cells decode these signals to make appropriate fate decisions. Here, we present new optogenetic reagents and an experimental pipeline for creating designer Nodal signaling patterns in live zebrafish embryos. Nodal receptors were fused to the light-sensitive heterodimerizing pair Cry2/CIB1N, and the Type II receptor was sequestered to the cytosol. The improved optoNodal2 reagents eliminate dark activity and improve response kinetics, without sacrificing dynamic range. We adapted an ultra-widefield microscopy platform for parallel light patterning in up to 36 embryos and demonstrated precise spatial control over Nodal signaling activity and downstream gene expression. Patterned Nodal activation drove precisely controlled internalization of endodermal precursors. Further, we used patterned illumination to generate synthetic signaling patterns in Nodal signaling mutants, rescuing several characteristic developmental defects. This study establishes an experimental toolkit for systematic exploration of Nodal signaling patterns in live embryos.
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    Photometric stereo endoscopy.
    (2013) Parot Fernández, Vicente José; Lim, Daryl; González, Germán; Traverso, Giovanni; Nishioka, Norman S.; Vakoc, Benjamin J.; Durr, Nicholas J.
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    Production of positron-gamma emitters for multiplexed PET (mPET) imaging.
    (2013) Herraiz, Joaquin L.; Lage, Eduardo; Parot Fernández, Vicente José; Dave, Shivang R.; Udías, Jose M.; Vaquero, J. J.; Muñoz-Martin, A.; Fraile, L. M.
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    Recovery and normalization of triple coincidences in PET.
    (2015) Lage, Eduardo; Parot Fernández, Vicente José; Moore, Stephen C.; Sitek, Arkadiusz; Udías, Jose M.; Dave, Shivang R.; Park, Mi‐Ae; Vaquero, Juan J.; Herraiz, Joaquin L.
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    Simulation of triple coincidences in PET.
    (2015) Cal González, J.; Lage, Eduardo; Herranz, E.; Vicente, E.; Udías, Jose M.; Moore, Stephen C.; Park, Mi‐Ae; Dave, Shivang R.; Parot Fernández, Vicente José; Herraiz, Joaquin L.
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    System for clinical photometric stereo endoscopy.
    (2014) Durr, Nicholas J.; González, Germán; Parot Fernández, Vicente José; Lim, Daryl; Traverso, Giovanni; Nishioka, Norman S.; Vakoc, Benjamin J.
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    The fractional Fourier transform and quadratic field magnetic resonance imaging
    (2011) Irarrázaval Mena, Pablo; Parot Fernández, Vicente José; Sing-Long C., Carlos A.
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    Voltage imaging and optogenetics reveal behaviour-dependent changes in hippocampal dynamics
    (2019) Adam, Yoav; Kim, J.J.; Lou, Shan; Zhao, Y.; Xie, M.E.; Brinks, D.; Wu, H.; Mostajo-Radji, M.A.; Kheifets, S.; Parot Fernández, Vicente José; Chettih, S.; Williams, K.J.; Gmeiner, B.; Farhi, Samouil L.; Madisen, Linda; Buchanan, E.K.; Kinsella, I.; Zhou, D.; Paninski, L.; Harvey, C.D.; Zeng, Hongkui; Arlotta, P.; Campbell, Robert E.; Cohen, Adam E.
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    Wide-Area All-Optical Neurophysiology in Acute Brain Slices
    (2019) Farhi, Samouil L.; Parot Fernández, Vicente José; Grama, Abhinav; Yamagata, Masahito; Abdelfattah, Ahmed S.; Adam, Yoav; Lou, Shan; Jun Kim, Jeong; Campbell, Robert E.; Cox, David D.; Adam E. Cohen