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adaptative optics

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https://www.readbyqxmd.com/read/28526865/realization-of-large-energy-proportion-in-the-central-lobe-by-coherent-beam-combination-based-on-conformal-projection-system
#1
Dong Zhi, Zhixin Zhang, Yanxing Ma, Xiaolin Wang, Zilun Chen, Wuming Wu, Pu Zhou, Lei Si
In this paper, we experimentally validate a tiled-aperture conformal projection system with the largest array filling factor and element beam truncation factor to the best of our knowledge. The conformal projection system, which is made up of a hexagonal adaptive fiber-optics collimator (AFOC) array with the proximate ideal intensity distributions, is fabricated and the performance of output beam is tested and evaluated properly and carefully. Both of the active phase-locking control and precise tip-tilt control are implemented successfully in the CBC of the hexagonal seven-beam-array...
May 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28525557/retinal-vascular-branching-in-healthy-and-diabetic-subjects
#2
Ting Luo, Thomas J Gast, Tyler J Vermeer, Stephen A Burns
Purpose: To measure the effect of nonproliferative diabetic retinopathy (NPDR) on retinal branching. To compare vascular branching in healthy and diabetic subjects with established biophysical models. Methods: Vascular bifurcations in arteries and veins were imaged in 17 NPDR and 26 healthy subjects with the Indiana adaptive optics scanning laser ophthalmoscope (AOSLO). Vessel measurements were grouped according to parent vessel diameters into large (≤50 ∼ <100 μm) and small (≤20 ∼ <50 μm) sizes...
May 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28524140/-influence-of-endothelial-graft-thickness-on-postoperative-visual-acuity
#3
S V Trufanov, S A Malozhen, V I Siplivyy, E P Salovarova
AIM: to assess the influence of the endothelial graft thickness on postoperative visual acuity following modified endothelial keratoplasty (UTDSAEK). MATERIAL AND METHODS: The study included 49 patients with pseudophakic bullous keratopathy and no concomitant disorders of either the retina or optic nerve. Ultrathin Descemet's stripping automated endothelial keratoplasty (UTDSAEK) was performed in all cases. Corneal graft thickness was measured 1 year after UTDSAEK by means of optical coherence tomography...
2017: Vestnik Oftalmologii
https://www.readbyqxmd.com/read/28522844/high-performance-pvc-gel-for-adaptive-micro-lenses-with-variable-focal-length
#4
Jin Woo Bae, Eun-Jae Shin, Jaeu Jeong, Dong-Soo Choi, Jong Eun Lee, Byeong Uk Nam, Liwei Lin, Sang-Youn Kim
This paper presents a bio-inspired adaptive micro-lens with electrically tunable focus made of non-ionic high-molecular-weight polyvinyl chloride (PVC) gel. The optical device mimics the design of the crystalline lens and ciliary muscle of the human eye. It consists of a plano-convex PVC gel micro-lens on Indium Tin Oxide (ITO) glass, confined with an annular electrode operating as an artificial ciliary muscle. Upon electrical activation, the electroactive adhesive force of the PVC gel is exerted on the annular anode electrode, which reduces the sagittal height of the plano-convex PVC gel lens, resulting in focal length variation of the micro-lens...
May 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28522835/reactivity-in-the-human-retinal-microvasculature-measured-during-acute-gas-breathing-provocations
#5
Angelina Duan, Phillip A Bedggood, Andrew B Metha, Bang V Bui
Although changes in vessel diameter following gas perturbation have been documented in retinal arterioles and venules, these responses have yet to be quantified in the smallest vessels of the human retina. Here, using in vivo adaptive optics, we imaged 3-25 µm diameter vessels of the human inner retinal circulation and monitored the effects of altered gas-breathing conditions. During isocapnic hyperoxia, definite constrictions were seen in 51% of vessel segments (mean ± SD for pre-capillary arterioles -9...
May 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28520626/multimodal-imaging-of-acute-exudative-polymorphous-vitelliform-maculopathy-with-optical-coherence-tomography-angiography-and-adaptive-optics-scanning-laser-ophthalmoscopy
#6
Dimitra Skondra, Peter L Nesper, Amani A Fawzi
PURPOSE: To report a case of acute exudative polymorphous vitelliform maculopathy including the findings of optical coherence tomography angiography and adaptive optics scanning laser ophthalmoscopy. METHODS: Findings on clinical examination, color fundus photography, spectral-domain optical coherence tomography, infrared reflectance, autofluorescence, optical coherence tomography angiography, and adaptive optics scanning laser ophthalmoscopy. RESULTS: A 54-year-old white man with no significant medical history and history of smoking presented with bilateral multiple serous and vitelliform detachments consistent with acute exudative polymorphous vitelliform maculopathy...
May 16, 2017: Retinal Cases & Brief Reports
https://www.readbyqxmd.com/read/28518063/visualizing-visual-adaptation
#7
Michael A Webster, Katherine E M Tregillus
Many techniques have been developed to visualize how an image would appear to an individual with a different visual sensitivity: e.g., because of optical or age differences, or a color deficiency or disease. This protocol describes a technique for incorporating sensory adaptation into the simulations. The protocol is illustrated with the example of color vision, but is generally applicable to any form of visual adaptation. The protocol uses a simple model of human color vision based on standard and plausible assumptions about the retinal and cortical mechanisms encoding color and how these adjust their sensitivity to both the average color and range of color in the prevailing stimulus...
April 24, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28511585/three-phase-adaptive-radiation-therapy-for-patients-with-nasopharyngeal-carcinoma-undergoing-intensity-modulated-radiation-therapy-dosimetric-analysis
#8
Shan Deng, Xu Liu, Heming Lu, Huixian Huang, Liuyang Shu, Hailan Jiang, Jinjian Cheng, Luxing Peng, Qiang Pang, Junzhao Gu, Jian Qin, Zhiping Lu, Ying Mo, Danling Wu, Yinglin Wei
Patients with nasopharyngeal carcinoma undergoing intensity-modulated radiation therapy may experience significant anatomic changes throughout the entire treatment course, and adaptive radiation therapy may be necessary to maintain optimal dose delivered both to the targets and to the critical structures. The timing of adaptive radiation therapy, however, is largely unknown. This study was to evaluate the dosimetric benefits of a 3-phase adaptive radiation therapy technique for nasopharyngeal carcinoma. Twenty patients with nasopharyngeal carcinoma treated with intensity-modulated radiation therapy were recruited prospectively...
January 1, 2017: Technology in Cancer Research & Treatment
https://www.readbyqxmd.com/read/28507508/improving-focal-photostimulation-of-cortical-neurons-with-pre-derived-wavefront-correction
#9
Julian M C Choy, Sharmila S Sané, Woei M Lee, Christian Stricker, Hans A Bachor, Vincent R Daria
Recent progress in neuroscience to image and investigate brain function has been made possible by impressive developments in optogenetic and opto-molecular tools. Such research requires advances in optical techniques for the delivery of light through brain tissue with high spatial resolution. The tissue causes distortions to the wavefront of the incoming light which broadens the focus and consequently reduces the intensity and degrades the resolution. Such effects are detrimental in techniques requiring focal stimulation...
2017: Frontiers in Cellular Neuroscience
https://www.readbyqxmd.com/read/28506273/inertial-measurement-systems-for-segments-and-joints-kinematics-assessment-towards-an-understanding-of-the-variations-in-sensors-accuracy
#10
Karina Lebel, Patrick Boissy, Hung Nguyen, Christian Duval
BACKGROUND: Joints kinematics assessment based on inertial measurement systems, which include attitude and heading reference system (AHRS), are quickly gaining in popularity for research and clinical applications. The variety of the tasks and contexts they are used in require a deep understanding of the AHRS accuracy for optimal data interpretation. However, published accuracy studies on AHRS are mostly limited to a single task measured on a limited number of segments and participants...
May 15, 2017: Biomedical Engineering Online
https://www.readbyqxmd.com/read/28501420/manipulation-of-visual-information-affects-control-strategy-during-a-visuomotor-tracking-task
#11
Paulina J M Bank, Lucas R M Dobbe, Carel G M Meskers, Jurriaan H de Groot, Erwin de Vlugt
Proper understanding of motor control requires insight into the extent and manner in which task performance and control strategy are influenced by various aspects of visual information. We therefore systematically manipulated the visual presentation (i.e., scaling factor and optical flow density) of a visuomotor tracking task without changing the task itself, and investigated the effect on performance, effort, motor control strategy (i.e., anticipatory or corrective steering) and underlying neuromechanical parameters (i...
May 10, 2017: Behavioural Brain Research
https://www.readbyqxmd.com/read/28501377/structural-changes-associated-with-delayed-dark-adaptation-in-age-related-macular-degeneration
#12
Inês Laíns, John B Miller, Dong H Park, Edem Tsikata, Samaneh Davoudi, Safa Rahmani, Jonathan Pierce, Rufino Silva, Teresa C Chen, Ivana K Kim, Demetrios Vavvas, Joan W Miller, Deeba Husain
PURPOSE: To examine the relationship between dark adaptation (DA) and optical coherence tomography (OCT)-based macular morphology in age-related macular degeneration (AMD). DESIGN: Prospective, cross-sectional study. PARTICIPANTS: Patients with AMD and a comparison group (>50 years) without any vitreoretinal disease. METHODS: All participants were imaged with spectral-domain OCT and color fundus photographs, and then staged for AMD (Age-related Eye Disease Study system)...
May 10, 2017: Ophthalmology
https://www.readbyqxmd.com/read/28499057/adaptive-optics-scanning-laser-ophthalmoscopy-and-multimodal-imaging-of-peau-d-orange-in-pseudoxanthoma-elasticum
#13
Alex C Onishi, Peter L Nesper, Amani A Fawzi
A 41-year-old male with pseudoxanthoma elasticum who presented with progressive vision loss in his left periphery is discussed. Bilateral angioid streaks, optic disc drusen, choroidal neovascularization, and peau d'orange were present. Imaging of the area with peau d'orange with adaptive optics scanning laser ophthalmoscopy and en face optical coherence tomography at Bruch's membrane (BM) revealed a pattern identical to the patches of peau d'orange visible with conventional fundus imaging techniques. These results show that structural abnormalities at the level of BM, likely a result of calcification, correlate with the characteristic "orange peel" pattern known as peau d'orange...
May 1, 2017: Ophthalmic Surgery, Lasers & Imaging Retina
https://www.readbyqxmd.com/read/28494152/low-temperature-synthesis-of-carbon-rich-nanoparticles-with-clickable-surface-for-functionalization
#14
Audrey Picard-Lafond, Jean-Francois Morin
Carbon nanoparticles (CNPs) are promising materials for optoelectronic and biomedical applications thanks to their optical properties, low production cost, and superior biocompatibility compared to traditional semi-conductor quantum dots. The countless synthetic methods reported allow a library of diverse CNPs structures and optical properties, guiding their subsequent applications. However, the current drawbacks lie mainly within these synthetic processes, as many of them require harsh conditions preventing control over morphology and often generating chemically inert nanoparticles...
May 11, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28490775/metasurface-freeform-nanophotonics
#15
Alan Zhan, Shane Colburn, Christopher M Dodson, Arka Majumdar
Freeform optics aims to expand the toolkit of optical elements by allowing for more complex phase geometries beyond rotational symmetry. Complex, asymmetric curvatures are employed to enhance the performance of optical components while minimizing their size. Unfortunately, these high curvatures and complex forms are often difficult to manufacture with current technologies, especially at the micron scale. Metasurfaces are planar sub-wavelength structures that can control the phase, amplitude, and polarization of incident light, and can thereby mimic complex geometric curvatures on a flat, wavelength-scale thick surface...
May 10, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28487555/adaptation-to-dietary-conditions-by-trehalose-metabolism-in-drosophila
#16
Tetsuo Yasugi, Takayuki Yamada, Takashi Nishimura
Trehalose is a non-reducing disaccharide that serves as the main sugar component of haemolymph in insects. Trehalose hydrolysis enzyme, called trehalase, is highly conserved from bacteria to humans. However, our understanding of the physiological role of trehalase remains incomplete. Here, we analyze the phenotypes of several Trehalase (Treh) loss-of-function alleles in a comparative manner in Drosophila. The previously reported mutant phenotype of Treh affecting neuroepithelial stem cell maintenance and differentiation in the optic lobe is caused by second-site alleles in addition to Treh...
May 9, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28483493/outcomes-in-autoimmune-retinopathy-patients-treated-with-rituximab
#17
Samaneh Davoudi, Nazanin Ebrahimiadib, Cagla Yasa, Damla D Sevgi, Ramak Roohipoor, Evangelia Papavasilieou, Jason Comander, Lucia Sobrin
PURPOSE: To evaluate clinical and ancillary testing, including adaptive optics, outcomes in autoimmune retinopathy (AIR) patients treated with rituximab. DESIGN: Retrospective, interventional case series. METHODS: patients: Sixteen AIR patients treated with rituximab. OBSERVATION PROCEDURES: All patients were treated with a loading and maintenance dose schedule of intravenous rituximab. Visual acuity (VA), electroretinography (ERG), and spectral-domain optical coherence tomography (SDOCT) and visual field (VF) results were recorded...
May 5, 2017: American Journal of Ophthalmology
https://www.readbyqxmd.com/read/28481364/large-field-of-view-imaging-by-multi-pupil-adaptive-optics
#18
Jung-Hoon Park, Lingjie Kong, Yifeng Zhou, Meng Cui
Adaptive optics can correct for optical aberrations. We developed multi-pupil adaptive optics (MPAO), which enables simultaneous wavefront correction over a field of view of 450 × 450 μm(2) and expands the correction area to nine times that of conventional methods. MPAO's ability to perform spatially independent wavefront control further enables 3D nonplanar imaging. We applied MPAO to in vivo structural and functional imaging in the mouse brain.
May 8, 2017: Nature Methods
https://www.readbyqxmd.com/read/28479850/automated-measurements-of-human-cone-photoreceptor-density-in-healthy-and-degenerative-retina-by-region-based-segmentation
#19
Suguru Miyagawa, Hisashi Fukuyama, Masakazu Hirota, Tatsuo Yamaguchi, Kazuo Kitamura, Takao Endo, Hiroyuki Kanda, Takeshi Morimoto, Takashi Fujikado
PURPOSE: The purpose of this study was to develop an algorithm based on region-based segmentation for automated calculations of human cone photoreceptor density of en face images obtained by an adaptive optics scanning laser ophthalmoscope (AOSLO). SUBJECTS AND METHODS: Cone mosaics of 15 eyes of 15 healthy subjects were photographed by a custom-built AOSLO. The cone density was calculated at 0.5, 1.0, and 1.5 mm temporal from the fovea using a region-based segmentation method (RSM) developed in our laboratory...
2017: Clinical Ophthalmology
https://www.readbyqxmd.com/read/28475934/delivery-of-cationic-quantum-dots-using-fusogenic-liposomes-in-living-cells
#20
Anna L L Matos, Goreti Pereira, Paulo E Cabral Filho, Beate S Santos, Adriana Fontes
Quantum dots (QDs) are fluorescent nanocrystals that present unique optical properties, especially a high photostability. However, their use for intracellular studies is still limited since their passage through the living cell membranes does not occur passively. In this work, we adapted the ethanol injection method to encapsulate cationic hydrophilic QDs into fusogenic liposomes, to deliver them in living cells. Liposomes were characterized using zeta potential, dynamic light scattering (DLS), fluorescence microscopy and transmission electron microscopy (TEM)...
April 23, 2017: Journal of Photochemistry and Photobiology. B, Biology
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