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Adaptive optics

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https://www.readbyqxmd.com/read/28110374/morphological-description-of-limbal-epithelium-searching-for-stem-cells-crypts-in-the-dog-cat-pig-cow-sheep-and-horse
#1
M Patruno, A Perazzi, T Martinello, A Blaseotto, E Di Iorio, I Iacopetti
The cornea provides protection and transparency to the eye, allowing an optimal sharpness view. In some pathological conditions the cornea is able to regenerate thanks to the presence of a stem cells reservoir present at the level of the transition area between cornea and sclera (limbus). Corneal cell therapies in Veterinary Medicine are really limited due to the lacking of knowledge about the anatomy of the limbal area, the putative presence of stem cells and their identification in domestic species. The aim of this study was to provide an overview of the main distinctive structural features of the sclero-corneal junction and conjunctival-corneal junction areas in some species of veterinary importance, using optic microscope observations of histological sections...
January 21, 2017: Veterinary Research Communications
https://www.readbyqxmd.com/read/28109903/an-apposition-compound-eye-adapted-for-nocturnal-vision-in-the-moth-midge-clogmia-albipunctata-williston-diptera-psychodidae
#2
Lei-Po Jia, Ai-Ping Liang
Morphology and anatomy, dark/light adaptational changes and optics of the compound eyes of the nocturnal moth midge Clogmia albipunctata (Williston) are studied. Its apposition type of eye consists of approximately 260 well-separated ommatidia. Each ommatidium features a biconvex corneal lens covered by corneal nipples measuring around 17 nm in height; a crystalline cone of the acone type; and an open (laterally fused) rhabdom formed by eight retinular cells (R1-R8). The corneal lens, whose biological significance is addressed, is composed of a thick yellow-coloured inner lens unit (ILU) surrounded by a thin, colourless outer lens unit (OLU)...
January 18, 2017: Journal of Insect Physiology
https://www.readbyqxmd.com/read/28108959/innovative-root-end-filling-materials-based-on-calcium-silicates-and-calcium-phosphates
#3
Ali Abedi-Amin, Arlinda Luzi, Massimo Giovarruscio, Gaetano Paolone, Atanaz Darvizeh, Victoria Vivó Agulló, Salvatore Sauro
This in vitro study evaluated the apical sealing ability, bioactivity and biocompatibility of an experimental calcium silicate-based and two light-curing calcium silicate/calcium-phosphate cements as potential root end filling materials. A calcium silicate Portland-based (Control PC), an experimental calcium silicate (Exp. PC) and two light-curing cements (LC-CaP; LC-Si/CaP) were assessed for their alkalinising activity (pH) and biocompatibility. Single-rooted human canines were endodontically treated, filled with gutta-percha and finally submitted to apicoectomy...
February 2017: Journal of Materials Science. Materials in Medicine
https://www.readbyqxmd.com/read/28105843/adaptive-pcr-based-on-hybridization-sensing-of-mirror-image-l-dna
#4
Nicholas M Adams, William E Gabella, Austin N Hardcastle, Frederick R Haselton
Polymerase chain reaction (PCR) is dependent on two key hybridization events during each cycle of amplification, primer annealing and product melting. To ensure that these hybridization events occur, current PCR approaches rely on temperature set points and reaction contents that are optimized and maintained using rigid thermal cycling programs and stringent sample preparation procedures. This report describes a fundamentally simpler and more robust PCR design that dynamically controls thermal cycling by more directly monitoring the two key hybridization events during the reaction...
January 3, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28105741/potential-use-of-cubic-phase-masks-for-extending-the-range-of-clear-vision-in-presbyopes-initial-calculation-and-simulation-studies
#5
Justo Arines, Citlalli Almaguer, Eva Acosta
PURPOSE: In this paper we analyse the potential use of a non-symmetrical optical element, a cubic phase mask, for extending the range of clear vision of presbyopic eyes. Additionally, we will discuss the appropriateness of the visual Strehl ratio to analyse this sort of presbyopic solution based on non-symmetrical phase masks contrasted with through-focus retinal images. METHODS: In order to evaluate the performance of the cubic phase mask we employed computational Fourier Optics to compute the different visual Strehl criteria as well as simulate the retinal images...
January 20, 2017: Ophthalmic & Physiological Optics: the Journal of the British College of Ophthalmic Opticians (Optometrists)
https://www.readbyqxmd.com/read/28102964/plasmonic-chirality-imprinting-on-nucleobase-displaying-supramolecular-nanohelices-by-metal-nucleobase-recognition
#6
Yiyang Lin, E Thomas Pashuck, Michael R Thomas, Nadav Amdursky, Shih-Ting Wang, Lesley W Chow, Molly M Stevens
Supramolecular self-assembly is an important process that enables the conception of complex structures mimicking biological motifs. Herein, we constructed helical fibrils through chiral self-assembly of nucleobase-peptide conjugates (NPCs), where achiral nucleobases are helically displayed on the surface of fibrils, comparable to polymerized nucleic acids. Selective binding between DNA and the NPC fibrils was observed with fluorescence polarization. Taking advantage of metal-nucleobase recognition, we highlight the possibility of deposition/assembly of plasmonic nanoparticles onto the fibrillar constructs...
January 19, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28101412/visualization-of-micro-capillaries-using-optical-coherence-tomography-angiography-with-and-without-adaptive-optics
#7
Matthias Salas, Marco Augustin, Laurin Ginner, Abhishek Kumar, Bernhard Baumann, Rainer Leitgeb, Wolfgang Drexler, Sonja Prager, Julia Hafner, Ursula Schmidt-Erfurth, Michael Pircher
The purpose of this work is to investigate the benefits of adaptive optics (AO) technology for optical coherence tomography angiography (OCTA). OCTA has shown great potential in non-invasively enhancing the contrast of vessels and small capillaries. Especially the capability of the technique to visualize capillaries with a lateral extension that is below the transverse resolution of the system opens unique opportunities in diagnosing retinal vascular diseases. However, there are some limitations of this technology such as shadowing and projection artifacts caused by overlying vasculature or the inability to determine the true extension of a vessel...
January 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28101398/wide-field-retinal-optical-coherence-tomography-with-wavefront-sensorless-adaptive-optics-for-enhanced-imaging-of-targeted-regions
#8
James Polans, Brenton Keller, Oscar M Carrasco-Zevallos, Francesco LaRocca, Elijah Cole, Heather E Whitson, Eleonora M Lad, Sina Farsiu, Joseph A Izatt
The peripheral retina of the human eye offers a unique opportunity for assessment and monitoring of ocular diseases. We have developed a novel wide-field (>70°) optical coherence tomography system (WF-OCT) equipped with wavefront sensorless adaptive optics (WSAO) for enhancing the visualization of smaller (<25°) targeted regions in the peripheral retina. We iterated the WSAO algorithm at the speed of individual OCT B-scans (~20 ms) by using raw spectral interferograms to calculate the optimization metric...
January 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28100483/electrophysiological-changes-in-12-year-old-children-born-mlp-reduced-vep-amplitude-in-mlp-children
#9
Lina H Raffa, Josefin Nilsson, Jovanna Dahlgren, Marita Andersson Grönlund
AIM: To study the electrophysiological changes in relation to fundus morphology in moderate-to-late preterm (MLP) children with no previous history of retinopathy of prematurity. METHODS: Visual acuity (VA), refraction and fundus variables measured by optical coherence tomography, pattern reversal visual evoked potentials and full-field electroretinography (ff-ERG) were obtained from 22 twelve-year-old MLP children (11 male, 11 female) and 21 full-term controls...
January 18, 2017: British Journal of Ophthalmology
https://www.readbyqxmd.com/read/28099163/adapting-smartphone-based-photoplethysmograpy-to-suboptimal-scenarios
#10
Augusto Garcia-Agundez, Tim Dutz, Stefan Goebel
Photoplethysmography (PPG) is an optical technique used to measure the heart rate (HR) and other cardiovascular variables by analyzing volume changes in the microvascular bed of tissue. At the moment, smartphone users can already measure their HR using PPG applications that use the smartphone's built-in camera. However, available applications are unreliable when artifacts are present, such as those caused by movement, finger pressure, or ambient light changes. This contribution aims to analyze the limitations of a smartphone-based PPG algorithm capable of measuring N-N intervals when such artifacts are present by comparing it to a 2-lead electrocardiography (ECG)...
January 18, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28098202/superresolution-imaging-of-clinical-formalin-fixed-paraffin-embedded-breast-cancer-with-single-molecule-localization-microscopy
#11
Matthew K Creech, Jing Wang, Xiaolin Nan, Summer L Gibbs
Millions of archived formalin-fixed, paraffin-embedded (FFPE) specimens contain valuable molecular insight into healthy and diseased states persevered in their native ultrastructure. To diagnose and treat diseases in tissue on the nanoscopic scale, pathology traditionally employs electron microscopy (EM), but this platform has significant limitations including cost and painstaking sample preparation. The invention of single molecule localization microscopy (SMLM) optically overcame the diffraction limit of light to resolve fluorescently labeled molecules on the nanoscale, leading to many exciting biological discoveries...
January 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28092516/single-camera-based-method-for-step-length-symmetry-measurement-in-unconstrained-elderly-home-monitoring
#12
Xi Cai, Guang Han, Xin Song, Jinkuan Wang
OBJECTIVE: Single-camera-based gait monitoring is unobtrusive, inexpensive and easy-to-use to monitor daily gait of seniors in their homes. However, most studies require subjects to walk perpendicularly to camera's optical axis or along some specified routes, which limits its application in elderly home monitoring. To build unconstrained monitoring environments, we propose a method to measure step length symmetry ratio (a useful gait parameter representing gait symmetry without significant relationship with age) from unconstrained straight walking using a single camera, without strict restrictions on walking directions or routes...
January 16, 2017: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28090774/biakamides-a-d-unique-polyketides-from-a-marine-sponge-act-as-selective-growth-inhibitors-of-tumor-cells-adapted-to-nutrient-starvation
#13
Naoyuki Kotoku, Ryosuke Ishida, Hirokazu Matsumoto, Masayoshi Arai, Kazunari Toda, Andi Setiawan, Osamu Muraoka, Motomasa Kobayashi
Biakamides A-D, novel unusually unique polyketides, were isolated from an Indonesian marine sponge (Petrosaspongia sp.) with a constructed bioassay using PANC-1 human pancreatic cancer cells. Through detailed analyses of the one- and two-dimensional nuclear magnetic resonance (NMR) spectra of biakamides, planar chemical structures possessing a terminal thiazole, two N-methyl amides, a chloromethylene, and a substituted butyryl moiety were obtained. After elucidation of the configuration of the secondary alcohol moiety in biakamides A and B, the absolute stereostructures of the two secondary methyl groups in biakamides A-D were determined by the asymmetric total syntheses of all possible stereoisomers from the optically pure monoprotected 2,4-dimethyl-1,5-diol...
January 16, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28088625/absence-of-dj-1-causes-age-related-retinal-abnormalities-in-association-with-increased-oxidative-stress
#14
Vera L Bonilha, Brent A Bell, Mary E Rayborn, Ivy S Samuels, Anna King, Joe G Hollyfield, Chengsong Xie, Huaibin Cai
Oxidative stress alters physiological function in most biological tissues and can lead to cell death. In the retina, oxidative stress initiates a cascade of events leading to focal loss of RPE and photoreceptors, which is thought to be a major contributing factor to geographic atrophy. Despite these implications, the molecular regulation of RPE oxidative stress under normal and pathological conditions remains largely unknown. A better understanding of the mechanisms involved in regulating RPE and photoreceptors oxidative stress response is greatly needed...
January 11, 2017: Free Radical Biology & Medicine
https://www.readbyqxmd.com/read/28081100/digital-equalization-of-time-delay-array-receivers-on-coherent-laser-communications
#15
Aniceto Belmonte
Field conjugation arrays use adaptive combining techniques on multi-aperture receivers to improve the performance of coherent laser communication links by mitigating the consequences of atmospheric turbulence on the down-converted coherent power. However, this motivates the use of complex receivers as optical signals collected by different apertures need to be adaptively processed, co-phased, and scaled before they are combined. Here, we show that multiple apertures, coupled with optical delay lines, combine retarded versions of a signal at a single coherent receiver, which uses digital equalization to obtain diversity gain against atmospheric fading...
January 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28079651/branch-retinal-vein-occlusion-secondary-to-a-retinal-arteriolar-macroaneurysm-a-novel-mechanism-supported-by-multimodal-imaging
#16
Yi Chen, Simon D M Chen, Fred K Chen
BACKGROUND/PURPOSE: To report a case of a branch retinal vein occlusion secondary to a retinal arteriolar macroaneurysm (RAM). METHODS: Retrospective case report describing examination findings, treatment outcome and unique multimodal imaging features demonstrated on fluorescein angiography, optical coherence tomography, optical coherence tomography angiography and adaptive optics photography of the retinal vessels and RAM. RESULTS: A 61-year-old man presented with 20/200 vision in the right eye because of a branch retinal vein occlusion secondary to a RAM...
January 10, 2017: Retinal Cases & Brief Reports
https://www.readbyqxmd.com/read/28078355/-compression-therapy-of-venous-leg-ulcers-in-the-decongestion-phase
#17
REVIEW
J Dissemond, S Eder, S Läuchli, H Partsch, M Stücker, W Vanscheidt
Compression therapy is the basis for successful treatment in most patients with venous leg ulcers. Concerning compression therapy, the initial phase of decongestion and the following phase of maintenance should be differentiated. While in the maintenance phase (ulcer) stocking systems are now frequently recommended, in the decongestion phase compression bandages are mostly still used, which however are often inappropriately applied. In German-speaking countries, compression therapy with short-stretch bandages has a long tradition...
January 11, 2017: Medizinische Klinik, Intensivmedizin und Notfallmedizin
https://www.readbyqxmd.com/read/28078170/computational-fluid-dynamics-assisted-characterization-of-parafoveal-hemodynamics-in-normal-and-diabetic-eyes-using-adaptive-optics-scanning-laser-ophthalmoscopy
#18
Yang Lu, Miguel O Bernabeu, Jan Lammer, Charles C Cai, Martin L Jones, Claudio A Franco, Lloyd Paul Aiello, Jennifer K Sun
Diabetic retinopathy (DR) is the leading cause of visual loss in working-age adults worldwide. Previous studies have found hemodynamic changes in the diabetic eyes, which precede clinically evident pathological alterations of the retinal microvasculature. There is a pressing need for new methods to allow greater understanding of these early hemodynamic changes that occur in DR. In this study, we propose a noninvasive method for the assessment of hemodynamics around the fovea (a region of the eye of paramount importance for vision)...
December 1, 2016: Biomedical Optics Express
https://www.readbyqxmd.com/read/28078077/a-novel-method-for-the-quantification-of-fatty-infiltration-in-skeletal-muscle
#19
Nicole K Biltz, Gretchen A Meyer
BACKGROUND: Fatty infiltration of the skeletal muscle is a common but poorly understood feature of many myopathies. It is best described in human muscle, where non-invasive imaging techniques and representative histology have been optimized to view and quantify infiltrating fat. However, human studies are limited in their ability to identify cellular and molecular mechanisms regulating fatty infiltration, a likely prerequisite to developing targeted interventions. As mechanistic investigations move to small animals, studies may benefit from new or adapted imaging tools optimized for high resolution and whole muscle quantification...
2017: Skeletal Muscle
https://www.readbyqxmd.com/read/28073372/a-novel-method-for-the-quantification-of-fatty-infiltration-in-skeletal-muscle
#20
Nicole K Biltz, Gretchen A Meyer
BACKGROUND: Fatty infiltration of the skeletal muscle is a common but poorly understood feature of many myopathies. It is best described in human muscle, where non-invasive imaging techniques and representative histology have been optimized to view and quantify infiltrating fat. However, human studies are limited in their ability to identify cellular and molecular mechanisms regulating fatty infiltration, a likely prerequisite to developing targeted interventions. As mechanistic investigations move to small animals, studies may benefit from new or adapted imaging tools optimized for high resolution and whole muscle quantification...
January 10, 2017: Skeletal Muscle
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