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adaptative optics

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https://www.readbyqxmd.com/read/28640147/human-photoreceptor-cone-density-measured-with-adaptive-optics-technology-rtx1-device-in-healthy-eyes-standardization-of-measurements
#1
Anna Zaleska-Żmijewska, Zbigniew M Wawrzyniak, Magdalena Ulińska, Jerzy Szaflik, Anna Dąbrowska, Jacek P Szaflik
The anatomic structures of the anterior segment of the eye enable correct reception of stimuli by the retina, which contains receptors that receive light impulses and transmit them to the visual cortex. The aim of this study was to assess the effect of the size of the sampling window in an adaptive optics (AO) flood-illumination retinal camera (rtx1) on cone density measurements in the eyes of healthy individuals and to investigate the differences in cone density and spacing in different quadrants of the retina...
June 2017: Medicine (Baltimore)
https://www.readbyqxmd.com/read/28638436/in-vivo-label-free-mapping-of-the-effect-of-a-photosystem-ii-inhibiting-herbicide-in-plants-using-chlorophyll-fluorescence-lifetime
#2
Elizabeth Noble, Sunil Kumar, Frederik G Görlitz, Chris Stain, Chris Dunsby, Paul M W French
BACKGROUND: In order to better understand and improve the mode of action of agrochemicals, it is useful to be able to visualize their uptake and distribution in vivo, non-invasively and, ideally, in the field. Here we explore the potential of plant autofluorescence (specifically chlorophyll fluorescence) to provide a readout of herbicide action across the scales utilising multiphoton-excited fluorescence lifetime imaging, wide-field single-photon excited fluorescence lifetime imaging and single point fluorescence lifetime measurements via a fibre-optic probe...
2017: Plant Methods
https://www.readbyqxmd.com/read/28637860/higher-order-neural-processing-tunes-motion-neurons-to-visual-ecology-in-three-species-of-hawkmoths
#3
A L Stöckl, D O'Carroll, E J Warrant
To sample information optimally, sensory systems must adapt to the ecological demands of each animal species. These adaptations can occur peripherally, in the anatomical structures of sensory organs and their receptors; and centrally, as higher-order neural processing in the brain. While a rich body of investigations has focused on peripheral adaptations, our understanding is sparse when it comes to central mechanisms. We quantified how peripheral adaptations in the eyes, and central adaptations in the wide-field motion vision system, set the trade-off between resolution and sensitivity in three species of hawkmoths active at very different light levels: nocturnal Deilephila elpenor, crepuscular Manduca sexta, and diurnal Macroglossum stellatarum...
June 28, 2017: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/28633153/association-between-visual-function-and-subretinal-drusenoid-deposits-in-normal-and-early-age-related-macular-degeneration-eyes
#4
David Neely, Anna V Zarubina, Mark E Clark, Carrie E Huisingh, Gregory R Jackson, Yuhua Zhang, Gerald McGwin, Christine A Curcio, Cynthia Owsley
PURPOSE: To examine the association between subretinal drusenoid deposits (SDDs) identified by multimodal retinal imaging and visual function in older eyes with normal macular health or in the earliest phases of age-related macular degeneration (AMD). METHODS: Age-related macular degeneration status for each eye was defined according to the Age-Related Eye Disease Study (AREDS) 9-step classification system (normal = Step 1, early AMD = Steps 2-4) based on color fundus photographs...
July 2017: Retina
https://www.readbyqxmd.com/read/28632879/reliability-and-agreement-between-metrics-of-cone-spacing-in-adaptive-optics-images-of-the-human-retinal-photoreceptor-mosaic
#5
Daniela Giannini, Giuseppe Lombardo, Letizia Mariotti, Nicholas Devaney, Sebastiano Serrao, Marco Lombardo
Purpose: To assess reliability and agreement among three metrics used to evaluate the distribution of cell distances in adaptive optics (AO) images of the cone mosaic. Methods: Using an AO flood illumination retinal camera, we acquired images of the cone mosaic in 20 healthy subjects and 12 patients with retinal diseases. The three spacing metrics studied were the center-to-center spacing (Scc), the local cone spacing (LCS), and the density recovery profile distance (DRPD)...
June 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28632158/on-the-application-of-image-processing-methods-for-bubble-recognition-to-the-study-of-subcooled-flow-boiling-of-water-in-rectangular-channels
#6
Concepción Paz, Marcos Conde, Jacobo Porteiro, Miguel Concheiro
This work introduces the use of machine vision in the massive bubble recognition process, which supports the validation of boiling models involving bubble dynamics, as well as nucleation frequency, active site density and size of the bubbles. The two algorithms presented are meant to be run employing quite standard images of the bubbling process, recorded in general-purpose boiling facilities. The recognition routines are easily adaptable to other facilities if a minimum number of precautions are taken in the setup and in the treatment of the information...
June 20, 2017: Sensors
https://www.readbyqxmd.com/read/28630799/optimized-process-for-fabrication-of-free-standing-silicon-nanophotonic-devices
#7
Paul Seidler
A detailed procedure is presented for fabrication of free-standing silicon photonic devices that accurately reproduces design dimensions while minimizing surface roughness. By reducing charging effects during inductively coupled-plasma reactive ion etching, undercutting in small, high-aspect ratio openings is reduced. Slot structures with a width as small as 40 nm and an aspect ratio of 5.5:1 can be produced with a nearly straight, vertical sidewall profile. Subsequent removal of an underlying sacrificial silicon dioxide layer by wet-etching to create free-standing devices is performed under conditions which suppress attack of the silicon...
May 2017: Journal of Vacuum Science and Technology. B, Nanotechnology & Microelectronics: Materials, Processing, Measurement, & Phenomena: JVST B
https://www.readbyqxmd.com/read/28629902/relationship-between-vessel-diameter-and-depth-measurements-within-the-limbus-using-ultra-high-resolution-optical-coherence-tomography
#8
Emmanuel Alabi, Natalie Hutchings, Kostadinka Bizheva, Trefford Simpson
PURPOSE: To establish a relationship between the diameter and depth position of vessels in the superior and inferior corneo-scleral limbus using ultra-high resolution optical coherence tomography (UHR-OCT). METHODS: Volumetric OCT images of the superior and inferior limbus were acquired from 14 healthy subjects with a research-grade UHR-OCT system. Differences in vessel diameter and depth between superior and inferior limbus were analyzed using repeated measured ANOVA in SPSS and R...
June 16, 2017: Journal of Optometry
https://www.readbyqxmd.com/read/28628128/adaptive-optics-improves-multiphoton-super-resolution-imaging
#9
Wei Zheng, Yicong Wu, Peter Winter, Robert Fischer, Damian Dalle Nogare, Amy Hong, Chad McCormick, Ryan Christensen, William P Dempsey, Don B Arnold, Joshua Zimmerberg, Ajay Chitnis, James Sellers, Clare Waterman, Hari Shroff
We improve multiphoton structured illumination microscopy using a nonlinear guide star to determine optical aberrations and a deformable mirror to correct them. We demonstrate our method on bead phantoms, cells in collagen gels, nematode larvae and embryos, Drosophila brain, and zebrafish embryos. Peak intensity is increased (up to 40-fold) and resolution recovered (up to 176 ± 10 nm laterally, 729 ± 39 nm axially) at depths ∼250 μm from the coverslip surface.
June 19, 2017: Nature Methods
https://www.readbyqxmd.com/read/28627942/diffusion-imaging-of-mild-traumatic-brain-injury-in-the-impact-accelerated-rodent-model-a-pilot-study
#10
Zora Kikinis, Marc Muehlmann, Ofer Pasternak, Sharon Peled, Praveen Kulkarni, Craig Ferris, Sylvain Bouix, Yogesh Rathi, Inga K Koerte, Steve Pieper, Alexander Yarmarkovich, Caryn L Porter, Bruce S Kristal, Martha E Shenton
PRIMARY OBJECTIVE: There is a need to understand pathologic processes of the brain following mild traumatic brain injury (mTBI). Previous studies report axonal injury and oedema in the first week after injury in a rodent model. This study aims to investigate the processes occurring 1 week after injury at the time of regeneration and degeneration using diffusion tensor imaging (DTI) in the impact acceleration rat mTBI model. RESEARCH DESIGN: Eighteen rats were subjected to impact acceleration injury, and three rats served as sham controls...
June 19, 2017: Brain Injury: [BI]
https://www.readbyqxmd.com/read/28614949/comparison-of-metrological-techniques-for-evaluation-of-the-impact-of-a-cosmetic-product-containing-hyaluronic-acid-on-the-properties-of-skin-surface
#11
Rahula Janiš, Vladimír Pata, Pavlína Egner, Jana Pavlačková, Andrea Zapletalová, Kristina Kejlová
The aim of this research was to evaluate mutual interchangeability of four principally different biometric instrumental techniques designed for objective measurement of changes in the physical, mechanical, and topographical properties of the skin surface treated with commercial antiaging cosmetic products with hyaluronic acid. The following instrumental devices were used: Visioscope PC 35, Corneometer Multiprobe Adapter MPA 6, Reviscometer RVM 600, and 3D scanner Talysurf CLI 500. The comparison of the individual methods was performed using cluster analysis...
June 14, 2017: Biointerphases
https://www.readbyqxmd.com/read/28614321/photonic-microwave-carrier-recovery-using-period-one-nonlinear-dynamics-of-semiconductor-lasers-for-ofdm-rof-coherent-detection
#12
Yu-Han Hung, Jhih-Heng Yan, Kai-Ming Feng, Sheng-Kwang Hwang
This study investigates an all-optical scheme based on period-one (P1) nonlinear dynamics of semiconductor lasers, which regenerates the microwave carrier of an orthogonal frequency division multiplexing radio-over-fiber (OFDM-RoF) signal and uses it as a microwave local oscillator for coherent detection. Through the injection locking established between the OFDM-RoF signal and the P1 dynamics, frequency synchronization with highly preserved phase quality is inherently achieved between the recovered microwave carrier and the microwave carrier of the OFDM-RoF signal...
June 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28614042/bnip3l-nix-dependent-mitophagy-regulates-cell-differentiation-via-metabolic-reprogramming
#13
Lorena Esteban-Martínez, Patricia Boya
Macroautophagy/autophagy is the process by which cellular components are degraded and recycled within the lysosome. These components include mitochondria, the selective degradation of which is known as mitophagy. Mitochondria are dynamic organelles that constantly adapt their morphology, function, and number to accommodate the metabolic needs of the cell. Extensive metabolic reconfiguration occurs during cell differentiation, when mitochondrial activity increases in most cell types. However, our data demonstrate that during physiological retinal ganglion cell (RGC) development, mitophagy-dependent metabolic reprogramming towards glycolysis regulates numbers of RGCs, which are the first neurons to differentiate in the retina and whose axons form the optic nerve...
June 14, 2017: Autophagy
https://www.readbyqxmd.com/read/28613053/-application-of-negative-molds-technology-based-on-three-dimensional-printing-in-digital-maxillofacial-prostheses
#14
X Y Gu, X B Chen, T Jiao, F Q Zhang, X Q Jiang
Objective: To explore a digital negative molds technique based on three-dimensional (3D) printing to assist in the manufacture of maxillofacial prostheses, and to improve the deficiency of the current clinical treatment. Methods: Seventeen patients with maxillofacial defects (including nasal defects, orbital defects, cheek defects, auricle defect) were scanned by means of facial optical scanning and computer tomography (CT). The 3D models were then reconstructed and global registration was made to merge the reconstructed models into a new digital model for 3D design...
June 9, 2017: Zhonghua Kou Qiang Yi Xue za Zhi, Zhonghua Kouqiang Yixue Zazhi, Chinese Journal of Stomatology
https://www.readbyqxmd.com/read/28608301/a-comparative-study-on-generating-simulated-landsat-ndvi-images-using-data-fusion-and-regression-method-the-case-of-the-korean-peninsula
#15
Mi Hee Lee, Soo Bong Lee, Yang Dam Eo, Sun Woong Kim, Jung-Hun Woo, Soo Hee Han
Landsat optical images have enough spatial and spectral resolution to analyze vegetation growth characteristics. But, the clouds and water vapor degrade the image quality quite often, which limits the availability of usable images for the time series vegetation vitality measurement. To overcome this shortcoming, simulated images are used as an alternative. In this study, weighted average method, spatial and temporal adaptive reflectance fusion model (STARFM) method, and multilinear regression analysis method have been tested to produce simulated Landsat normalized difference vegetation index (NDVI) images of the Korean Peninsula...
July 2017: Environmental Monitoring and Assessment
https://www.readbyqxmd.com/read/28607486/a-retinal-code-for-motion-along-the-gravitational-and-body-axes
#16
Shai Sabbah, John A Gemmer, Ananya Bhatia-Lin, Gabrielle Manoff, Gabriel Castro, Jesse K Siegel, Nathan Jeffery, David M Berson
Self-motion triggers complementary visual and vestibular reflexes supporting image-stabilization and balance. Translation through space produces one global pattern of retinal image motion (optic flow), rotation another. We examined the direction preferences of direction-sensitive ganglion cells (DSGCs) in flattened mouse retinas in vitro. Here we show that for each subtype of DSGC, direction preference varies topographically so as to align with specific translatory optic flow fields, creating a neural ensemble tuned for a specific direction of motion through space...
June 7, 2017: Nature
https://www.readbyqxmd.com/read/28603518/microbial-extracellular-polymeric-substances-epss-in-ocean-systems
#17
REVIEW
Alan W Decho, Tony Gutierrez
Microbial cells (i.e., bacteria, archaea, microeukaryotes) in oceans secrete a diverse array of large molecules, collectively called extracellular polymeric substances (EPSs) or simply exopolymers. These secretions facilitate attachment to surfaces that lead to the formation of structured 'biofilm' communities. In open-water environments, they also lead to formation of organic colloids, and larger aggregations of cells, called 'marine snow.' Secretion of EPS is now recognized as a fundamental microbial adaptation, occurring under many environmental conditions, and one that influences many ocean processes...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28602957/mitochondrial-dynamics-signaling-is-shifted-toward-fusion-in-muscles-of-very-old-hip-fractured-patients-results-from-the-sarcopenia-in-hip-fracture-shift-exploratory-study
#18
Anna Picca, Riccardo Calvani, Maria Lorenzi, Amerigo Menghi, Marco Galli, Raffaele Vitiello, Francesco Randisi, Roberto Bernabei, Francesco Landi, Emanuele Marzetti
BACKGROUND: Mitochondrial quality control (MQC) is crucial for maintaining mitochondrial fitness. We investigated MQC signaling in muscle of old hip-fractured patients. METHODS: Twenty-three patients, enrolled in the Sarcopenia in HIp FracTure (SHIFT) study, were categorized into old (OL; n=8) and very old groups (VOL; n=15) using 85years as the cut-off. The expression of a set of MQC signaling proteins was assayed in vastus lateralis muscle biopsies. RESULTS: The content of lysosome-associated membrane protein 2, microtubule-associated protein 1 light chain 3B, optic atrophy protein 1, fission protein 1 (Fis1), peroxisome proliferator-activated receptor-γ coactivator-1α, and forkhead box O3 was unvaried between groups...
June 7, 2017: Experimental Gerontology
https://www.readbyqxmd.com/read/28599336/-intraoperative-optical-coherence-tomography-in-vitreoretinal-surgery-clinical-experiences-and-future-developments
#19
Mathias M Maier, Ali Nasseri, Carsten Framme, Sabrina Bohnacker, Matthias D Becker, Dominik Heinrich, Hansjürgen Agostini, Nikolaus Feucht, Chris P Lohmann, Lars Olof Hattenbach
Purpose High resolution optical coherence tomography (OCT) enables better visualization of ophthalmic microstructures than conventional imaging. When using an ophthalmic microscope, integrated optical coherence tomography (iOCT) high resolution real time visualization is possible. Methods We report on the first 110 patients operated on using a microscope integrated OCT (iOCT) during surgical procedures for the treatment of various posterior segment pathologies. Results Microstructural changes that appeared during surgery were depicted precisely by iOCT, and the morphology visualized before and after each surgical step was used to help deciding how to adapt the surgical flow...
June 9, 2017: Klinische Monatsblätter Für Augenheilkunde
https://www.readbyqxmd.com/read/28596194/influence-of-ultra-low-dose-and-iterative-reconstructions-on-the-visualization-of-orbital-soft-tissues-on-maxillofacial-ct
#20
G Widmann, D Juranek, F Waldenberger, P Schullian, A Dennhardt, R Hoermann, M Steurer, E-M Gassner, W Puelacher
BACKGROUND AND PURPOSE: Dose reduction on CT scans for surgical planning and postoperative evaluation of midface and orbital fractures is an important concern. The purpose of this study was to evaluate the variability of various low-dose and iterative reconstruction techniques on the visualization of orbital soft tissues. MATERIALS AND METHODS: Contrast-to-noise ratios of the optic nerve and inferior rectus muscle and subjective scores of a human cadaver were calculated from CT with a reference dose protocol (CT dose index volume = 36...
June 8, 2017: AJNR. American Journal of Neuroradiology
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