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Color contrast sensitivity

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https://www.readbyqxmd.com/read/28411334/normative-values-for-a-tablet-computer-based-application-to-assess-chromatic-contrast-sensitivity
#1
Lakshmi Bodduluri, Mei Ying Boon, Malcolm Ryan, Stephen J Dain
Tablet computer displays are amenable for the development of vision tests in a portable form. Assessing color vision using an easily accessible and portable test may help in the self-monitoring of vision-related changes in ocular/systemic conditions and assist in the early detection of disease processes. Tablet computer-based games were developed with different levels of gamification as a more portable option to assess chromatic contrast sensitivity. Game 1 was designed as a clinical version with no gaming elements...
April 14, 2017: Behavior Research Methods
https://www.readbyqxmd.com/read/28405391/red-fluorescence-of-the-triplefin-tripterygion-delaisi-is-increasingly-visible-against-background-light-with-increasing-depth
#2
Pierre-Paul Bitton, Ulrike K Harant, Roland Fritsch, Connor M Champ, Shelby E Temple, Nico K Michiels
The light environment in water bodies changes with depth due to the absorption of short and long wavelengths. Below 10 m depth, red wavelengths are almost completely absent rendering any red-reflecting animal dark and achromatic. However, fluorescence may produce red coloration even when red light is not available for reflection. A large number of marine taxa including over 270 fish species are known to produce red fluorescence, yet it is unclear under which natural light environment fluorescence contributes perceptively to their colours...
March 2017: Royal Society Open Science
https://www.readbyqxmd.com/read/28355632/cross-modal-attention-influences-auditory-contrast-sensitivity-decreasing-visual-load-improves-auditory-thresholds-for-amplitude-and-frequency-modulated-sounds
#3
Vivian M Ciaramitaro, Hiu Mei Chow, Luke G Eglington
We used a cross-modal dual task to examine how changing visual-task demands influenced auditory processing, namely auditory thresholds for amplitude- and frequency-modulated sounds. Observers had to attend to two consecutive intervals of sounds and report which interval contained the auditory stimulus that was modulated in amplitude (Experiment 1) or frequency (Experiment 2). During auditory-stimulus presentation, observers simultaneously attended to a rapid sequential visual presentation-two consecutive intervals of streams of visual letters-and had to report which interval contained a particular color (low load, demanding less attentional resources) or, in separate blocks of trials, which interval contained more of a target letter (high load, demanding more attentional resources)...
March 1, 2017: Journal of Vision
https://www.readbyqxmd.com/read/28322387/color-resolution-improvement-of-the-dark-field-microscopy-imaging-of-single-light-scattering-plasmonic-nanoprobes-for-microrna-visual-detection
#4
Jun Zhou, Peng Fei Gao, Hong Zhi Zhang, Gang Lei, Lin Ling Zheng, Hui Liu, Cheng Zhi Huang
Imaging of light scattering plasmonic nanoparticles (PNPs) with the aid of the dark-field microscopy imaging (iDFM) technique has attracted wide attention owing to its high signal-to-noise ratio, but to improve the color resolution and contrast of dark-field microscopy (DFM) images of single light scattering PNPs in a small spectral variation environment is still a challenge. In this study, a new color analytical method for resolving the resolution and contrast in DFM images has been developed and further applied for colorimetric analysis using the digital image processing technique...
March 21, 2017: Nanoscale
https://www.readbyqxmd.com/read/28282060/visual-dysfunction-and-its-correlation-with-retinal-changes-in-patients-with-alzheimer-s-disease
#5
V Polo, M J Rodrigo, E Garcia-Martin, S Otin, J M Larrosa, M I Fuertes, M P Bambo, L E Pablo, M Satue
AimTo evaluate visual dysfunction and its correlation with structural changes in the retina in patients with Alzheimer's disease (AD).MethodsPatients with AD (n=24) and controls (n=24) underwent evaluation of visual acuity (VA), color vision (using the Farnsworth and L'Anthony desaturated (D) 15 color tests), and contrast sensitivity vision (CSV; using the Pelli-Robson chart and CSV-1000E test) to measure visual dysfunction. Structural measurements of the retinal nerve fiber layer (RNFL) and macular thickness were obtained using spectral domain-optical coherence tomography (SD-OCT)...
March 10, 2017: Eye
https://www.readbyqxmd.com/read/28273721/neurochemical-responses-to-chromatic-and-achromatic-stimuli-in-the-human-visual-cortex
#6
Petr Bednařík, Ivan Tkáč, Federico Giove, Lynn E Eberly, Dinesh K Deelchand, Felipe R Barreto, Silvia Mangia
In the present study, we aimed at determining the metabolic responses of the human visual cortex during the presentation of chromatic and achromatic stimuli, known to preferentially activate two separate clusters of neuronal populations (called "blobs" and "interblobs") with distinct sensitivity to color or luminance features. Since blobs and interblobs have different cytochrome-oxidase (COX) content and micro-vascularization level (i.e., different capacities for glucose oxidation), different functional metabolic responses during chromatic vs...
January 1, 2017: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/28237426/the-role-of-the-human-visual-cortex-in-assessment-of-the-long-term-durability-of-retinal-gene-therapy-in-follow-on-rpe65-clinical-trial-patients
#7
Manzar Ashtari, Elena S Nikonova, Kathleen A Marshall, Gloria J Young, Puya Aravand, Wei Pan, Gui-Shuang Ying, Aimee E Willett, Mani Mahmoudian, Albert M Maguire, Jean Bennett
PURPOSE: Gene therapy (GT) has offered immense hope to individuals who are visually impaired because of RPE65 mutations. Although GT has shown great success in clinical trials enrolling these individuals, evidence for stability and durability of this treatment over time is still unknown. Herein we explored the value of functional magnetic resonance imaging (fMRI) as an objective measure to assess independently the longevity of retinal GT. DESIGN: Individuals with RPE65 mutations who underwent GT in their worse-seeing eye in a phase 1 clinical trial received a second subretinal injection in their contralateral eye in a follow-on clinical trial...
February 22, 2017: Ophthalmology
https://www.readbyqxmd.com/read/28214221/relationship-between-the-melanocortin-1-receptor-mc1r-variant-r306ter-and-physiological-responses-to-mechanical-or-thermal-stimuli-in-labrador-retriever-dogs
#8
Tania E Perez, Katrina L Mealey, Neal S Burke, Tamara L Grubb, Michael H Court, Stephen A Greene
OBJECTIVE: Variants in the MC1R gene have been associated with red hair color and sensitivity to pain in humans. The study objective was to determine if a relationship exists between MC1R genotype and physiological thermal or mechanical nociceptive thresholds in Labrador Retriever dogs. STUDY DESIGN: Prospective experimental study. ANIMALS: Thirty-four Labrador Retriever dogs were included in the study following public requests for volunteers...
January 11, 2017: Veterinary Anaesthesia and Analgesia
https://www.readbyqxmd.com/read/28208185/evaluation-of-progressive-visual-dysfunction-and-retinal-degeneration-in-patients-with-parkinson-s-disease
#9
Maria Satue, Maria J Rodrigo, Javier Obis, Elisa Vilades, Hector Gracia, Sofia Otin, Maria I Fuertes, Raquel Alarcia, Jose A Crespo, Vicente Polo, Jose M Larrosa, Luis E Pablo, Elena Garcia-Martin
Purpose: To quantify changes in visual function parameters and in the retinal nerve fiber layer and macular thickness over a 5-year period in patients with Parkinson's disease (PD). Methods: Thirty patients with PD and 30 healthy subjects underwent a complete ophthalmic evaluation, including assessment of visual acuity, contrast sensitivity vision, color vision, and retinal evaluation with spectral-domain optical coherence tomography (SD-OCT). All subjects were reevaluated after 5 years to quantify changes in visual function parameters, the retinal nerve fiber layer, and macular thickness...
February 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28180194/prospective-evaluation-of-quasistatic-ultrasound-elastography-use-compared-with-baseline-us-for-parotid-gland-lesions-preliminary-results-of-elasticity-contrast-index-eci-evaluation
#10
Vito Cantisani, Emanuele David, Armando De Virgilio, Paul S Sidhu, Hektor Grazhdani, Antonio Greco, Marco De Vincentiis, Alessandro Corsi, Flaminia De Cristofaro, Luca Brunese, Fabrizio Calliada, Alfredo Blandino, Mario Tombolini, Giorgio Ascenti, Roberto Stramare, Marcello Caratozzolo, Ferdinando D'Ambrosio
AIMS: To assess the diagnostic value of elasticity contrast index (ECI) elastography, in comparison with conventional ultrasound for the differentiation of benign and malignant parotid lesions. MATERIAL AND METHODS: Sixty-three consecutive patients with parotid gland tumors, treated surgically at a single tertiary center were enrolled. Ultrasound evaluation consisted of B-mode, color-Doppler and quasistatic ultrasound elastography (USE), conducted with the ECI technique...
January 31, 2017: Medical Ultrasonography
https://www.readbyqxmd.com/read/28159970/the-clinical-phenotype-of-cnga3-related-achromatopsia-pretreatment-characterization-in-preparation-of-a-gene-replacement-therapy-trial
#11
Ditta Zobor, Annette Werner, Franco Stanzial, Francesco Benedicenti, Günther Rudolph, Ulrich Kellner, Christian Hamel, Sten Andréasson, Gergely Zobor, Torsten Strasser, Bernd Wissinger, Susanne Kohl, Eberhart Zrenner
Purpose: The purpose of this study was to clinically characterize patients with CNGA3-linked achromatopsia (CNGA3-ACHM) in preparation of a gene therapy trial. Methods: Thirty-six patients (age 7-56 years) with complete (cACHM) or incomplete (iACHM) CNGA3-ACHM were examined, including detailed psychophysical tests, extended electrophysiology, and assessment of morphology by fundus autofluorescence and spectral-domain optical coherence tomography (SD-OCT). Results: Mean best-corrected visual acuity was 0...
February 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28146487/plasmon-enhanced-sensitivity-of-spin-based-sensors-based-on-a-diamond-ensemble-of-nitrogen-vacancy-color-centers
#12
Hao Guo, Yulei Chen, Dajin Wu, Rui Zhao, Jun Tang, Zongmin Ma, Chenyang Xue, Wendong Zhang, Jun Liu
A method for enhancement of the sensitivity of a spin sensor based on an ensemble of nitrogen vacancy (NV) color centers was demonstrated. Gold nanoparticles (NPs) were deposited on the bulk diamond, which had NV centers distributed on its surface. The experimental results demonstrate that, when using this simple method, plasmon enhancement of the deposited gold NPs produces an improvement of ∼10 times in the quantum efficiency and has also improved the signal-to-noise ratio by approximately ∼2.5 times...
February 1, 2017: Optics Letters
https://www.readbyqxmd.com/read/28131591/mild-extraction-methods-using-aqueous-glucose-solution-for-the-analysis-of-natural-dyes-in-textile-artefacts-dyed-with-dyer-s-madder-rubia-tinctorum-l
#13
Lauren Ford, Robert L Henderson, Christopher M Rayner, Richard S Blackburn
Madder (Rubia tinctorum L.) has been widely used as a red dye throughout history. Acid-sensitive colorants present in madder, such as glycosides (lucidin primeveroside, ruberythric acid, galiosin) and sensitive aglycons (lucidin), are degraded in the textile back extraction process; in previous literature these sensitive molecules are either absent or present in only low concentrations due to the use of acid in typical textile back extraction processes. Anthraquinone aglycons alizarin and purpurin are usually identified in analysis following harsh back extraction methods, such those using solvent mixtures with concentrated hydrochloric acid at high temperatures...
March 3, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28112128/visual-function-of-children-with-visual-and-other-disabilities-in-oman-a-case-series
#14
Urmi Gogri, Rajiv Khandekar, Salah Al Harby
BACKGROUND: We assessed the visual functioning of the children with special needs in Oman between 2009 and 2012. We present the methods of assessing different visual functions, outcomes, and interventions carried out to improve their functioning. METHODS: Optometrists assessed visual functions of children of "Day care centres" in Oman. Experts further assessed them and provided low vision care. Ocular movements, refractive corrections, near, distance, contrast color, motion, field of vision, and cognitive visual function test results were noted...
December 2016: Indian Journal of Ophthalmology
https://www.readbyqxmd.com/read/28100658/maps-of-cone-opsin-input-to-mouse-v1-and-higher-visual-areas
#15
Issac Rhim, Gabriela Coello-Reyes, Hee-Kyoung Ko, Ian Nauhaus
Studies in the mouse retina have characterized the spatial distribution of an anisotropic ganglion cell and photoreceptor mosaic, which provides a solid foundation to study how the cortex pools from afferent parallel color channels. In particular, the mouse's retinal mosaic exhibits a gradient of wavelength sensitivity along its dorsoventral axis. Cones at the ventral extreme mainly express S opsin, which is sensitive to ultraviolet (UV) wavelengths. Then, moving toward the retina's dorsal extreme, there is a transition to M-opsin dominance...
April 1, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28079755/macular-pigment-distribution-responses-to-high-dose-zeaxanthin-supplementation-in-patients-with-macular-telangiectasia-type-2
#16
Rene Y Choi, Aruna Gorusupudi, Kimberley Wegner, Mohsen Sharifzadeh, Werner Gellermann, Paul S Bernstein
PURPOSE: To analyze macular pigment (MP) amount and distribution in patients with macular telangiectasia Type 2 receiving oral zeaxanthin supplementation in a randomized, open-label, interventional trial. METHODS: Eight macular telangiectasia Type 2 patients were randomized to 10 mg or 20 mg of zeaxanthin per day. At each visit, best-corrected visual acuity, contrast sensitivity, fundus biomicroscopy, color fundus photography, autofluorescence imaging, optical coherence tomography, and serum carotenoid levels were tested...
January 10, 2017: Retina
https://www.readbyqxmd.com/read/28079243/serum-levels-of-vitamin-a-visual-function-and-ocular-surface-after-bariatric-surgery
#17
Luana Paula Nogueira de Araújo Brandão, Lucio Vilar, Bernardo Menelau Cavalcanti, Pedro Henrique Amorim Brandão, Tiago Eugênio Faria E Arantes, Josemberg Marins Campos
BACKGROUND: - Bariatric surgery is the most effective treatment for severe obesity, but the surgery increases the risk of developing nutritional deficiencies, such as vitamin A deficiency. In human metabolism, vitamin A plays a role in vision. OBJECTIVE: - To evaluate serum vitamin A, visual function and ocular surface of patients undergoing bariatric surgery. METHODS: - A cross-sectional and analytical study was conduced with 28 patients undergoing bariatric surgery for at least 6 months...
January 2017: Arquivos de Gastroenterologia
https://www.readbyqxmd.com/read/28076391/assessing-sexual-dicromatism-the-importance-of-proper-parameterization-in-tetrachromatic-visual-models
#18
Pierre-Paul Bitton, Kevyn Janisse, Stéphanie M Doucet
Perceptual models of animal vision have greatly contributed to our understanding of animal-animal and plant-animal communication. The receptor-noise model of color contrasts has been central to this research as it quantifies the difference between two colors for any visual system of interest. However, if the properties of the visual system are unknown, assumptions regarding parameter values must be made, generally with unknown consequences. In this study, we conduct a sensitivity analysis of the receptor-noise model using avian visual system parameters to systematically investigate the influence of variation in light environment, photoreceptor sensitivities, photoreceptor densities, and light transmission properties of the ocular media and the oil droplets...
2017: PloS One
https://www.readbyqxmd.com/read/28031067/effects-of-faba-beans-with-different-concentrations-of-vicine-and-convicine-on-egg-production-egg-quality-and-red-blood-cells-in-laying-hens
#19
M Lessire, V Gallo, M Prato, O Akide-Ndunge, G Mandili, P Marget, P Arese, G Duc
The faba bean (Vicia faba L.) is a potential source of proteins for poultry, mainly for laying hens whose protein requirements are lower than those of other birds such as growing broilers and turkeys. However, this feedstuff contains anti-nutritional factors, that is, vicine (V) and convicine (C) that are already known to reduce laying hen performance. The aim of the experiment reported here was to evaluate the effects of a wide range of dietary V and C concentrations in laying hens. Two trials were performed with laying hens fed diets including 20% or 25% of faba bean genotypes highly contrasting in V+C content...
December 29, 2016: Animal: An International Journal of Animal Bioscience
https://www.readbyqxmd.com/read/28030559/breeding-dispersal-by-birds-in-a-dynamic-urban-ecosystem
#20
John M Marzluff, Jack H DeLap, M David Oleyar, Kara A Whittaker, Beth Gardner
Changes in land cover during urbanization profoundly affect the diversity of bird communities, but the demographic mechanisms affecting diversity are poorly known. We advance such understanding by documenting how urbanization influences breeding dispersal-the annual movement of territorial adults-of six songbird species in the Seattle, WA, USA metropolitan area. We color-banded adults and mapped the centers of their annual breeding activities from 2000-2010 to obtain 504 consecutive movements by 337 adults...
2016: PloS One
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