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Adaptive optics

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https://www.readbyqxmd.com/read/28728169/correlations-between-macular-skin-and-serum-carotenoids
#1
Christopher D Conrady, James P Bell, Brian M Besch, Aruna Gorusupudi, Kelliann Farnsworth, Igor Ermakov, Mohsen Sharifzadeh, Maia Ermakova, Werner Gellermann, Paul S Bernstein
Purpose: Ocular and systemic measurement and imaging of the macular carotenoids lutein and zeaxanthin have been employed extensively as potential biomarkers of AMD risk. In this study, we systematically compare dual wavelength retinal autofluorescence imaging (AFI) of macular pigment with skin resonance Raman spectroscopy (RRS) and serum carotenoid levels in a clinic-based population. Methods: Eighty-eight patients were recruited from retina and general ophthalmology practices from a tertiary referral center and excluded only if they did not have all three modalities tested, had a diagnosis of macular telangiectasia (MacTel) or Stargardt disease, or had poor AFI image quality...
July 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28727809/optical-modelling-of-a-supplementary-tunable-air-spaced-goggle-lens-for-rodent-eye-imaging
#2
Elie de Lestrange-Anginieur, Xiaoyun Jiang, Qiushi Ren
Aberration variations severely degrade retinal imaging in small animal eyes. Previously, the approach of a goggle lens with a matching corneal index was proposed to overcome the on-axis resolution limit of static imaging systems, which allows the use of the full eye pupil. But this technique didn't address the problem of the large power variation, and the ensuing aberration on and off-axis, when dealing with small animal eyes. In this study, we present the concept of a tunable goggle lens, designed to compensate individual ocular aberration for different rodent eye powers...
2017: PloS One
https://www.readbyqxmd.com/read/28719742/integrated-smartphone-app-chip-system-for-on-site-ppb-level-colorimetric-quantitation-of-aflatoxins
#3
Xiaochun Li, Fan Yang, Jessica X H Wong, Hua-Zhong Yu
We demonstrate herein an integrated, smartphone-app-chip (SPAC) system for on-site quantitation of food toxins, as demonstrated with aflatoxin B1 (AFB1), at parts-per-billion (ppb) level in food products. The detection is based on an indirect competitive immunoassay fabricated on a transparent plastic chip with the assistance of a microfluidic channel plate. A 3D-printed optical accessory attached to a smartphone is adapted to align the assay chip and to provide uniform illumination for imaging, with which high-quality images of the assay chip are captured by the smartphone camera and directly processed using a custom-developed Android app...
July 18, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28717573/in-vivo-digital-wavefront-sensing-using-swept-source-oct
#4
Abhishek Kumar, Lara M Wurster, Matthias Salas, Laurin Ginner, Wolfgang Drexler, Rainer A Leitgeb
Sub-aperture based digital adaptive optics is demonstrated in a fiber based point scanning optical coherence tomography system using a 1060 nm swept source laser. To detect optical aberrations in-vivo, a small lateral field of view of ~[Formula: see text] is scanned on the sample at a high volume rate of 17 Hz (~1.3 kHz B-scan rate) to avoid any significant lateral and axial motion of the sample, and is used as a "guide star" for the sub-aperture based DAO. The proof of principle is demonstrated using a micro-beads phantom sample, wherein a significant root mean square wavefront error (RMS WFE) of 1...
July 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28713646/progression-of-local-glaucomatous-damage-near-fixation-as-seen-with-adaptive-optics-imaging
#5
Donald C Hood, Dongwon Lee, Ravivarn Jarukasetphon, Jason Nunez, Maria A Mavrommatis, Richard B Rosen, Robert Ritch, Alfredo Dubra, Toco Y P Chui
PURPOSE: Deep glaucomatous defects near fixation were followed over time with an adaptive optics-scanning light ophthalmoscope (AO-SLO) to better understand the progression of these defects and to explore the use of AO-SLO in detecting them. METHODS: Six eyes of 5 patients were imaged with an AO-SLO from 2 to 4 times for a range of 14.6 to 33.6 months. All eyes had open-angle glaucoma with deep defects in the superior visual field (VF) near fixation as defined by 10-2 VFs with 5 or more points less than -15 dB; two of the eyes had deep defects in the inferior VF as well...
July 2017: Translational Vision Science & Technology
https://www.readbyqxmd.com/read/28708142/experimental-validation-of-phase-only-pre-compensation-over-494%C3%A2-%C3%A2-m-free-space-propagation
#6
Aoife Brady, René Berlich, Nina Leonhard, Teresa Kopf, Paul Böttner, Ramona Eberhardt, Claudia Reinlein
It is anticipated that ground-to-geostationary orbit (GEO) laser communication will benefit from pre-compensation of atmospheric turbulence for laser beam propagation through the atmosphere. Theoretical simulations and laboratory experiments have determined its feasibility; extensive free-space experimental validation has, however, yet to be fulfilled. Therefore, we designed and implemented an adaptive optical (AO)-box which pre-compensates an outgoing laser beam (uplink) using the measurements of an incoming beam (downlink)...
July 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28707032/receptor-heterogeneity-in-optical-biosensors
#7
Ryan M Evans, David A Edwards
Scientists measure rate constants associated with biochemical reactions in an optical biosensor-an instrument in which ligand molecules are convected through a flow cell over a surface to which receptors are immobilized. We quantify transport effects on such reactions by modeling the associated convection-diffusion equation with a reaction boundary condition. In experimental situations, the full PDE model reduces to a set of unwieldy integrodifferential equations (IDEs). Employing common physical assumptions, we may reduce the system to an ODE model, which is more useful in practice, and which can be easily adapted to the inverse problem of finding rate constants...
July 13, 2017: Journal of Mathematical Biology
https://www.readbyqxmd.com/read/28706756/impact-of-vital-dyes-on-cell-viability-and-transduction-efficiency-of-aav-vectors-used-in-retinal-gene-therapy-surgery-an-in-vitro-and-in-vivo-analysis
#8
Anna P Salvetti, Maria I Patrício, Alun R Barnard, Harry O Orlans, Doron G Hickey, Robert E MacLaren
PURPOSE: Treatment of inherited retinal degenerations using adeno-associated viral (AAV) vectors involves delivery by subretinal injection. In the latter stages, alteration of normal anatomy may cause difficulty in visualizing the retinotomy, retinal detachment extension, and vector diffusion. Vital dyes may be useful surgical adjuncts, but their safety and impact on AAV transduction are largely unknown. METHODS: The effects of Sodium Fluorescein (SF), Membrane Blue (MB), and Membrane Blue Dual (DB) at a range of dilutions were assessed on human embryonic kidney cells in vitro using an AAV2-green fluorescent protein (GFP) reporter at different multiplicities of infection...
July 2017: Translational Vision Science & Technology
https://www.readbyqxmd.com/read/28702672/chitosan-stabilized-platinum-nanoparticles-as-effective-oxidase-mimics-for-colorimetric-detection-of-acid-phosphatase
#9
Hao-Hua Deng, Xiu-Ling Lin, Yin-Huan Liu, Ke-Lin Li, Qiong-Qiong Zhuang, Hua-Ping Peng, Ai-Lin Liu, Xing-Hua Xia, Wei Chen
Capping molecules on the surface of nanomaterials not only enhance the dispersion and stability of nanomaterials but also greatly facilitate their surface modification and biological applications. However, most capping molecules can severely block the active sites of the catalytic core, thereby decreasing the enzymatic activity of nanomaterial-based enzyme mimics. This work demonstrates the superiority of chitosan (Ch) as a capping molecule for synthesizing catalytic platinum nanoparticles (PtNPs). The experimental results show that Ch simultaneously exhibits an excellent stabilizing effect and enhances the oxidase-like activity of PtNPs...
July 12, 2017: Nanoscale
https://www.readbyqxmd.com/read/28700902/a-novel-algorithm-to-detect-glaucoma-risk-using-texton-and-local-configuration-pattern-features-extracted-from-fundus-images
#10
U Rajendra Acharya, Shreya Bhat, Joel E W Koh, Sulatha V Bhandary, Hojjat Adeli
Glaucoma is an optic neuropathy defined by characteristic damage to the optic nerve and accompanying visual field deficits. Early diagnosis and treatment are critical to prevent irreversible vision loss and ultimate blindness. Current techniques for computer-aided analysis of the optic nerve and retinal nerve fiber layer (RNFL) are expensive and require keen interpretation by trained specialists. Hence, an automated system is highly desirable for a cost-effective and accurate screening for the diagnosis of glaucoma...
June 29, 2017: Computers in Biology and Medicine
https://www.readbyqxmd.com/read/28697898/fusion-domains-guide-the-oriented-insertion-of-light-driven-proton-pumps-into-liposomes
#11
Noah Ritzmann, Johannes Thoma, Stephan Hirschi, David Kalbermatter, Dimitrios Fotiadis, Daniel J Müller
One major objective of synthetic biology is the bottom-up assembly of minimalistic nanocells consisting of lipid or polymer vesicles as architectural scaffolds and of membrane and soluble proteins as functional elements. However, there is no reliable method to orient membrane proteins reconstituted into vesicles. Here, we introduce a simple approach to orient the insertion of the light-driven proton pump proteorhodopsin (PR) into liposomes. To this end, we engineered red or green fluorescent proteins to the N- or C-terminus of PR, respectively...
July 8, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28696172/multimodal-imaging-in-retinal-vasculitis
#12
Aniruddha Agarwal, Rubbia Afridi, Rupesh Agrawal, Diana V Do, Vishali Gupta, Quan Dong Nguyen
Retinal vasculitis presents with inflammation involving the retinal vasculature as an isolated disease or in combination with other ocular or systemic conditions. This entity may be associated with a wide variety of clinical manifestations such as vascular sheathing, cotton-wool spots, retinal ischemia, and neovascularization. Often, retinal vasculitis and its complications lead to diagnostic challenges in identifying the exact etiology of the inflammation. Ancillary investigations such as fundus photography, fluorescein angiography, and more recently, adaptive optics imaging and optical coherence tomography angiography, may provide valuable information that help in establishing the exact diagnosis and initiation of appropriate therapy...
June 2017: Ocular Immunology and Inflammation
https://www.readbyqxmd.com/read/28694501/retinal-blood-flow-velocity-change-in-parafoveal-capillary-after-topical-tafluprost-treatment-in-eyes-with-primary-open-angle-glaucoma
#13
Yuto Iida, Tadamichi Akagi, Hideo Nakanishi, Hanako Ohashi Ikeda, Satoshi Morooka, Kenji Suda, Tomoko Hasegawa, Satoshi Yokota, Munemitsu Yoshikawa, Akihito Uji, Nagahisa Yoshimura
Although ocular circulation at the retina and optic disc is known to be associated with the pathology of glaucoma, direct measurement of blood flow velocity has been difficult to obtain. This prospective observational study enrolled 11 consecutive patients with treatment-naïve primary open-angle glaucoma (POAG) and 11 healthy subjects, and the effects of topical tafluprost treatment on ocular circulation were examined at baseline and at 1, 4, and 12 weeks after initiating treatment with topical tafluprost on POAG patients using multiple modalities, which include adaptive optics scanning laser ophthalmoscopy (AOSLO)...
July 10, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28689397/invention-of-the-guide-catheter-irrigation-monitoring-device-for-neuroendovascular-therapy
#14
Ayca Ozkul, Jong-Hyun Park, Dong-Seung Shin, Ali Yilmaz, Bum-Tae Kim
OBJECTIVE: The thromboembolic events during neuroendovascular therapy (NET) are the major complications of concern that can be occasionally fatal. The thrombotic occlusion of the guide catheter for NET is thought to be the risk of the thromboembolic events. We have developed an idea for inventing the monitoring system of the continuous irrigation through the guide catheter. We herein present a unique invention of the guide catheter irrigation monitoring device. METHODS: We have developed ideas for preventing the thrombotic occlusion of the guide catheter...
July 2017: Journal of Korean Neurosurgical Society
https://www.readbyqxmd.com/read/28687853/alterations-to-the-foveal-cone-mosaic-of-diabetic-patients
#15
Lucie Sawides, Kaitlyn A Sapoznik, Alberto de Castro, Brittany R Walker, Thomas J Gast, Ann E Elsner, Stephen A Burns
Purpose: We measured localized changes occurring in the foveal cone photoreceptors and related defects in the cone mosaic to alterations in the nearby retinal vasculature. Methods: The central 4° of the retina of 54 diabetic (53.7 ± 12.5 years) and 85 control (35.8 ± 15.2 years) participants were imaged with the Indiana adaptive optics scanning laser ophthalmoscope. Foveal cones and overlying retinal capillaries were imaged and infrared scanning laser ophthalmoscopy (IR SLO) images and optical coherence tomography (OCT) B-scans were obtained...
July 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28687596/expression-and-light-dependent-translocation-of-%C3%AE-arrestin-in-the-visual-system-of-the-terrestrial-slug-limax-valentianus
#16
Ryota Matsuo, Yuka Takatori, Shun Hamada, Mitsumasa Koyanagi, Yuko Matsuo
Vertebrates, cephalopods, and arthropods are equipped with eyes having the highest spatiotemporal resolution among the animal phyla. In parallel, it is only the animals in these three phyla that have visual arrestin specialized for the termination of visual signaling triggered by opsin, in addition to ubiquitously expressed β-arrestin that serves in terminating general G protein-coupled receptor signaling. Indeed, visual arrestin in Drosophila and rodents translocates to the opsin-rich subcellular region in response to light to reduce the overall sensitivity of photoreceptors in an illuminated environment (i...
July 7, 2017: Journal of Experimental Biology
https://www.readbyqxmd.com/read/28685469/optical-design-of-adaptive-optics-confocal-scanning-laser-ophthalmoscope-with-two-deformable-mirrors
#17
Jinsheng Yang, Yuanyuan Wang, Xuejun Rao, Ling Wei, Xiqi Li, Yi He
We describe the optical design of a confocal scanning laser ophthalmoscope with two deformable mirrors. Spherical mirrors are used for pupil relay. Defocus aberration of the human eye is corrected by a Badal focusing structure and astigmatism aberration is corrected by a deformable mirror. The main optical system achieves a diffraction-limited performance through the entire scanning field (6 mm pupil, 3 degrees on pupil plane). The performance of the optical system, with correction of defocus and astigmatism, is also evaluated...
2017: Advances in Experimental Medicine and Biology
https://www.readbyqxmd.com/read/28685107/optical-response-of-heterogeneous-polymer-layers-containing-silver-nanostructures
#18
Miriam Carlberg, Florent Pourcin, Olivier Margeat, Judikaël Le Rouzo, Gérard Berginc, Rose-Marie Sauvage, Jörg Ackermann, Ludovic Escoubas
This work is focused on the study of the optical properties of silver nanostructures embedded in a polymer host matrix. The introduction of silver nanostructures in polymer thin films is assumed to result in layers having adaptable optical properties. Thin film layers with inclusions of differently shaped nanoparticles, such as nanospheres and nanoprisms, and of different sizes, are optically characterized. The nanoparticles are produced by a simple chemical synthesis at room temperature in water. The plasmonic resonance peaks of the different colloidal solutions range from 390 to 1300 nm...
2017: Beilstein Journal of Nanotechnology
https://www.readbyqxmd.com/read/28684434/optical-measurement-of-stem-xylem-vulnerability
#19
Timothy John Brodribb, Marc Carriqui, Sylvain Delzon, Christopher Lucani
The vulnerability of plant water transport tissues to a loss of function by cavitation during water stress is a key indicator of the survival capabilities of plant species during drought. Quantifying this important metric has been greatly advanced by non-invasive techniques that allow embolisms to be directly viewed in the vascular system. Here we present a new method for evaluating the spatial and temporal propagation of embolising bubbles in the stem xylem during imposed water stress. We demonstrate how the "optical method", previously used in leaves, can be adapted to measure the xylem vulnerability of stems...
July 6, 2017: Plant Physiology
https://www.readbyqxmd.com/read/28681906/refractive-changes-induced-by-spherical-aberration-in-laser-correction-procedures-an-adaptive-optics-study
#20
Alfredo Amigó, Paula Martinez-Sorribes, Margarita Recuerda
PURPOSE: To study the effect on vision of induced negative and positive spherical aberration within the range of laser vision correction procedures. METHODS: In 10 eyes (mean age: 35.8 years) under cyclopegic conditions, spherical aberration values from -0.75 to +0.75 µm in 0.25-µm steps were induced by an adaptive optics system. Astigmatism and spherical refraction were corrected, whereas the other natural aberrations remained untouched. Visual acuity, depth of focus defined as the interval of vision for which the target was still perceived acceptable, contrast sensitivity, and change in spherical refraction associated with the variation in pupil diameter from 6 to 2...
July 1, 2017: Journal of Refractive Surgery
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