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https://www.readbyqxmd.com/read/28747737/open-source-software-for-automatic-detection-of-cone-photoreceptors-in-adaptive-optics-ophthalmoscopy-using-convolutional-neural-networks
#1
David Cunefare, Leyuan Fang, Robert F Cooper, Alfredo Dubra, Joseph Carroll, Sina Farsiu
Imaging with an adaptive optics scanning light ophthalmoscope (AOSLO) enables direct visualization of the cone photoreceptor mosaic in the living human retina. Quantitative analysis of AOSLO images typically requires manual grading, which is time consuming, and subjective; thus, automated algorithms are highly desirable. Previously developed automated methods are often reliant on ad hoc rules that may not be transferable between different imaging modalities or retinal locations. In this work, we present a convolutional neural network (CNN) based method for cone detection that learns features of interest directly from training data...
July 26, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28746418/a-user-friendly-low-cost-turbidostat-with-versatile-growth-rate-estimation-based-on-an-extended-kalman-filter
#2
Stefan A Hoffmann, Christian Wohltat, Kristian M Müller, Katja M Arndt
For various experimental applications, microbial cultures at defined, constant densities are highly advantageous over simple batch cultures. Due to high costs, however, devices for continuous culture at freely defined densities still experience limited use. We have developed a small-scale turbidostat for research purposes, which is manufactured from inexpensive components and 3D printed parts. A high degree of spatial system integration and a graphical user interface provide user-friendly operability. The used optical density feedback control allows for constant continuous culture at a wide range of densities and offers to vary culture volume and dilution rates without additional parametrization...
2017: PloS One
https://www.readbyqxmd.com/read/28746132/three-dimensional-cross-platform-planning-for-complex-spinal-procedures-a-new-method-adaptive-to-different-navigation-systems
#3
Michael Kosterhon, Angelika Gutenberg, Sven R Kantelhardt, Jens Conrad, Amr Nimer Amr, Joachim Gawehn, Alf Giese
STUDY DESIGN: A feasibility study. OBJECTIVE: To develop a method based on the DICOM standard which transfers complex 3-dimensional (3D) trajectories and objects from external planning software to any navigation system for planning and intraoperative guidance of complex spinal procedures. SUMMARY OF BACKGROUND DATA: There have been many reports about navigation systems with embedded planning solutions but only few on how to transfer planning data generated in external software...
August 2017: Clinical Spine Surgery
https://www.readbyqxmd.com/read/28743458/s-phenylpiracetam-a-selective-dat-inhibitor-reduces-body-weight-gain-without-influencing-locomotor-activity
#4
Liga Zvejniece, Baiba Svalbe, Edijs Vavers, Marina Makrecka-Kuka, Elina Makarova, Vilnis Liepins, Ivars Kalvinsh, Edgars Liepinsh, Maija Dambrova
S-phenylpiracetam is an optical isomer of phenotropil, which is a clinically used nootropic drug that improves physical condition and cognition. Recently, it was shown that S-phenylpiracetam is a selective dopamine transporter (DAT) inhibitor that does not influence norepinephrine (NE) or serotonin (5-HT) receptors. The aim of the present study was to study the effects of S-phenylpiracetam treatment on body weight gain, blood glucose and leptin levels, and locomotor activity. Western diet (WD)-fed mice and obese Zucker rats were treated daily with peroral administration of S-phenylpiracetam for 8 and 12weeks, respectively...
July 22, 2017: Pharmacology, Biochemistry, and Behavior
https://www.readbyqxmd.com/read/28739381/role-of-parafovea-in-blur-perception
#5
Abinaya Priya Venkataraman, Aiswaryah Radhakrishnan, Carlos Dorronsoro, Linda Lundström, Susana Marcos
The blur experienced by our visual system is not uniform across the visual field. Additionally, lens designs with variable power profile such as contact lenses used in presbyopia correction and to control myopia progression create variable blur from the fovea to the periphery. The perceptual changes associated with varying blur profile across the visual field are unclear. We therefore measured the perceived neutral focus with images of different angular subtense (from 4° to 20°) and found that the amount of blur, for which focus is perceived as neutral, increases when the stimulus was extended to cover the parafovea...
July 21, 2017: Vision Research
https://www.readbyqxmd.com/read/28738413/reliability-and-repeatability-of-cone-density-measurements-in-patients-with-stargardt-disease-and-rpgr-associated-retinopathy
#6
Preena Tanna, Melissa Kasilian, Rupert Strauss, James Tee, Angelos Kalitzeos, Sergey Tarima, Alexis Visotcky, Alfredo Dubra, Joseph Carroll, Michel Michaelides
Purpose: To assess reliability and repeatability of cone density measurements by using confocal and (nonconfocal) split-detector adaptive optics scanning light ophthalmoscopy (AOSLO) imaging. It will be determined whether cone density values are significantly different between modalities in Stargardt disease (STGD) and retinitis pigmentosa GTPase regulator (RPGR)-associated retinopathy. Methods: Twelve patients with STGD (aged 9-52 years) and eight with RPGR-associated retinopathy (aged 11-31 years) were imaged using both confocal and split-detector AOSLO simultaneously...
July 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28738202/predicting-carbon-benefits-from-climate-smart-agriculture-high-resolution-carbon-mapping-and-uncertainty-assessment-in-el-salvador
#7
Sean Patrick Kearney, Nicholas C Coops, Kai M A Chan, Steven J Fonte, Pablo Siles, Sean M Smukler
Agroforestry management in smallholder agriculture can provide climate change mitigation and adaptation benefits and has been promoted as 'climate-smart agriculture' (CSA), yet has generally been left out of international and voluntary carbon (C) mitigation agreements. A key reason for this omission is the cost and uncertainty of monitoring C at the farm scale in heterogeneous smallholder landscapes. A largely overlooked alternative is to monitor C at more aggregated scales and develop C contracts with groups of land owners, community organizations or C aggregators working across entire landscapes (e...
July 21, 2017: Journal of Environmental Management
https://www.readbyqxmd.com/read/28736670/wavefront-sensorless-adaptive-optics-oct-with-the-done-algorithm-for-in-vivo-human-retinal-imaging-invited
#8
Hans R G W Verstraete, Morgan Heisler, Myeong Jin Ju, Daniel Wahl, Laurens Bliek, Jeroen Kalkman, Stefano Bonora, Yifan Jian, Michel Verhaegen, Marinko V Sarunic
In this report, which is an international collaboration of OCT, adaptive optics, and control research, we demonstrate the Data-based Online Nonlinear Extremum-seeker (DONE) algorithm to guide the image based optimization for wavefront sensorless adaptive optics (WFSL-AO) OCT for in vivo human retinal imaging. The ocular aberrations were corrected using a multi-actuator adaptive lens after linearization of the hysteresis in the piezoelectric actuators. The DONE algorithm succeeded in drastically improving image quality and the OCT signal intensity, up to a factor seven, while achieving a computational time of 1 ms per iteration, making it applicable for many high speed applications...
April 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28736660/effect-of-higher-order-aberrations-and-intraocular-scatter-on-contrast-sensitivity-measured-with-a-single-instrument
#9
Junlei Zhao, Fei Xiao, Haoxin Zhao, Yun Dai, Yudong Zhang
Higher-order aberrations (HOAs) and intraocular scatter lead to the degradation of image quality on the retina, and consequently deteriorate subjective visual performance. In this article, we modified an adaptive optics double-pass system to combine objective and subjective visual testing capabilities. Employing the modified DP system, we investigated the effects of HOAs and intraocular scatter on contrast sensitivity. Contrast sensitivity measurements were performed with HOAs either retained or corrected by adaptive optics, and with scatter either remaining at the natural eye-induced level or further enhanced by a set of three different scatter filters...
April 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28736657/high-temporal-resolution-aberrometry-in-a-50-eye-population-and-implications-for-adaptive-optics-error-budget
#10
Jessica Jarosz, Pedro Mecê, Jean-Marc Conan, Cyril Petit, Michel Paques, Serge Meimon
We formed a database gathering the wavefront aberrations of 50 healthy eyes measured with an original custom-built Shack-Hartmann aberrometer at a temporal frequency of 236 Hz, with 22 lenslets across a 7-mm diameter pupil, for a duration of 20 s. With this database, we draw statistics on the spatial and temporal behavior of the dynamic aberrations of the eye. Dynamic aberrations were studied on a 5-mm diameter pupil and on a 3.4 s sequence between blinks. We noted that, on average, temporal wavefront variance exhibits a n(-2) power-law with radial order n and temporal spectra follow a f(-1...
April 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28736655/comparison-of-vision-through-surface-modulated-and-spatial-light-modulated-multifocal-optics
#11
Maria Vinas, Carlos Dorronsoro, Aiswaryah Radhakrishnan, Clara Benedi-Garcia, Edward Anthony LaVilla, Jim Schwiegerling, Susana Marcos
Spatial-light-modulators (SLM) are increasingly used as active elements in adaptive optics (AO) systems to simulate optical corrections, in particular multifocal presbyopic corrections. In this study, we compared vision with lathe-manufactured multi-zone (2-4) multifocal, angularly and radially, segmented surfaces and through the same corrections simulated with a SLM in a custom-developed two-active-element AO visual simulator. We found that perceived visual quality measured through real manufactured surfaces and SLM-simulated phase maps corresponded highly...
April 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28735531/origami-and-kirigami-nanocomposites
#12
Lizhi Xu, Terry C Shyu, Nicholas A Kotov
The arts of origami and kirigami inspired numerous examples of macroscale hierarchical structures with high degree of reconfigurability and multiple functionalities. Extension of kirigami and origami patterning to micro-, meso-, and nano-scales enabled production of nanocomposites with unusual combination of properties, transitioning these techniques to the toolbox of materials design. Various subtractive and additive fabrication techniques applicable to nanocomposites and out-of-plane deformation of patterns enable a technological framework to negotiate often contradictory structural requirements for materials properties...
July 23, 2017: ACS Nano
https://www.readbyqxmd.com/read/28735013/simultaneous-intrinsic-signal-imaging-of-auditory-and-visual-cortex-reveals-profound-effects-of-acute-hearing-loss-on-visual-processing
#13
Manuel Teichert, Jürgen Bolz
It has been suggested that primary sensory cortices do not work in isolation but receive subthreshold inputs originating from other senses. However, repercussions of an acute loss of one sense on multimodal sensory processing remain elusive. Here we investigated the early effects of acute hearing loss on visual processing in adult mice. For this, we developed a method to simultaneously map the primary auditory (A1) and visual cortex (V1) using periodic intrinsic optical imaging. We found that reducing sound evoked A1 responsiveness due to the induction of conductive hearing loss (CHL) led to a concomitant increase of visually driven V1 activity...
July 19, 2017: NeuroImage
https://www.readbyqxmd.com/read/28731267/heuristic-knowledge-based-planning-for-single-isocenter-stereotactic-radiosurgery-to-multiple-brain-metastases
#14
Benjamin P Ziemer, Parag Sanghvi, Jona Hattangadi-Gluth, Kevin L Moore
PURPOSE: Single-isocenter, volumetric modulated arc therapy (VMAT) stereotactic radiosurgery (SRS) for multiple brain metastases (multi-mets) can deliver highly conformal dose distributions and reduce overall patient treatment time compared to other techniques. However, treatment planning for multi-met cases is highly complex due to variability in numbers and sizes of brain metastases, as well as their relative proximity to organs-at-risk (OARs). The purpose of this study was to automate the VMAT planning of multi-met cases through a knowledge-based planning (KBP) approach that adapts single target SRS dose predictions to multiple target predictions...
July 21, 2017: Medical Physics
https://www.readbyqxmd.com/read/28731071/-potential-impact-of-colors-of-filters-used-in-sunglasses-on-the-melatonin-suppression-process
#15
Grzegorz Owczarek, Grzegorz Gralewicz, Agnieszka Wolska, Natalia Skuza, Piotr Jurowski
BACKGROUND: In this article the methods for determining spectral transmittance of optical radiation in the visible waveband range through selected materials used as optical filters against solar glare were described. MATERIAL AND METHODS: Transmittance coefficients specified for the fraction of light passing through tested filters, taking into account the mechanism of eye adaptation to daylight and night vision and the melatonin suppression process were compared for 4 dyed sunglass filters...
July 26, 2017: Medycyna Pracy
https://www.readbyqxmd.com/read/28730968/modulation-of-the-immune-system-for-the-treatment-of-glaucoma
#16
Katharina Bell, Nadine von Thun Und Hohenstein-Blaul, Julia Teister, Franz H Grus
At present intraocular pressure (IOP) lowering therapies are the only approach to treat glaucoma. Neuroprotective strategies to protect the retinal ganglion cells (RGC) from apoptosis are lacking to date. Results from clinical studies revealed altered immunoreactivities against retinal and optic nerve antigens in sera and aqueous humor of glaucoma patients and point toward an autoimmune involvement in glaucomatous neurodegeneration and RGC death. IgG accumulations along with plasma cells were found localised in human glaucomatous retinae in a pro-inflammatory environment possibly maintained by microglia...
July 19, 2017: Current Neuropharmacology
https://www.readbyqxmd.com/read/28730808/determination-of-the-relationship-between-expression-and-functional-activity-of-multidrug-resistance-associated-protein-1-using-scanning-electrochemical-microscopy
#17
David Polcari, Javier Alejandro Hernandez-Castro, Kebin Li, Matthias Geissler, Janine Mauzeroll
Cancer cells can develop multidrug resistance (MDR) after prolonged exposure to chemotherapeutic drugs, which is a severe impediment to successful treatment. MDR is typically associated with transmembrane proteins mediating efflux of administered drugs, thereby keeping their intracellular concentration below the threshold required to kill cells. Although expression assays based on flow cytometry and immunostaining have shown that multidrug resistance-associated protein 1 (MRP1) is prevalent in many cancer types, the functional activity of this efflux pump is more difficult to elucidate, especially at the single-cell level...
July 21, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28730088/effect-of-even-and-odd-order-aberrations-on-the-accommodation-response
#18
Aikaterini I Moulakaki, Antonio J Del Águila-Carrasco, José J Esteve-Taboada, Robert Montés-Micó
AIM: To investigate the potential effect that odd and even-order monochromatic aberrations may have on the accommodation response of the human eye. METHODS: Eight healthy subjects with astigmatism below 1 D, best corrected visual acuity 20/20 or better and normal findings in an ophthalmic examination were enrolled. An adaptive optics system was used in order to measure the accommodation response of the subjects' eyes under different conditions: with the natural aberrations being present, and with the odd and even-order aberrations being corrected...
2017: International Journal of Ophthalmology
https://www.readbyqxmd.com/read/28728169/correlations-between-macular-skin-and-serum-carotenoids
#19
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
#20
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
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