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Adaptive optics

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https://www.readbyqxmd.com/read/28811364/mechanosensing-drives-acuity-of-%C3%AE-%C3%AE-t-cell-recognition
#1
Yinnian Feng, Kristine N Brazin, Eiji Kobayashi, Robert J Mallis, Ellis L Reinherz, Matthew J Lang
T lymphocytes use surface [Formula: see text] T-cell receptors (TCRs) to recognize peptides bound to MHC molecules (pMHCs) on antigen-presenting cells (APCs). How the exquisite specificity of high-avidity T cells is achieved is unknown but essential, given the paucity of foreign pMHC ligands relative to the ubiquitous self-pMHC array on an APC. Using optical traps, we determine physicochemical triggering thresholds based on load and force direction. Strikingly, chemical thresholds in the absence of external load require orders of magnitude higher pMHC numbers than observed physiologically...
August 15, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28811303/adaptive-camouflage-what-can-be-learned-from-the-wetting-behaviour-of-the-tropical-flat-bugs-dysodius-lunatus-and-dysodiusmagnus
#2
Florian Hischen, Vladislav Reiswich, Desirée Kupsch, Ninon De Mecquenem, Michael Riedel, Markus Himmelsbach, Agnes Weth, Ernst Heiss, Oskar Armbruster, Johannes Heitz, Werner Baumgartner
The neotropical flat bug species Dysodius lunatus and Dysodius magnus show a fascinating camouflage principle, as their appearance renders the animal hardly visible on the bark of trees. However, when getting wet due to rain, bark changes its colour and gets darker. In order to keep the camouflage effect, it seems that some Dysodius species benefit from their ability to hold a water film on their cuticle and therefore change their optical properties when also wetted by water. This camouflage behaviour requires the insect to have a hydrophilic surface and passive surface structures which facilitate the liquid spreading...
August 15, 2017: Biology Open
https://www.readbyqxmd.com/read/28808961/zebrafish-as-a-model-for-the-study-of-host-virus-interactions
#3
Peng Fei Zou, Pin Nie
Zebrafish (Danio rerio) has become an increasingly important model for in vivo and in vitro studies on host-pathogen interaction, offering scientists with optical accessibility and genetic tractability, and a vertebrate-type immunity that can be separated into innate and adaptive ones. Although it is shown in previous studies that few species of viruses can naturally infect zebrafish, the spring viraemia of carp virus (SVCV), a rhabdovirus that causes contagious acute hemorrhagic viraemia in a variety of cyprinid fishes, can infect zebrafish by both injection and static immersion methods in laboratory conditions...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28808014/adaptive-benefit-of-cross-modal-plasticity-following-cochlear-implantation-in-deaf-adults
#4
Carly A Anderson, Ian M Wiggins, Pádraig T Kitterick, Douglas E H Hartley
It has been suggested that visual language is maladaptive for hearing restoration with a cochlear implant (CI) due to cross-modal recruitment of auditory brain regions. Rehabilitative guidelines therefore discourage the use of visual language. However, neuroscientific understanding of cross-modal plasticity following cochlear implantation has been restricted due to incompatibility between established neuroimaging techniques and the surgically implanted electronic and magnetic components of the CI. As a solution to this problem, here we used functional near-infrared spectroscopy (fNIRS), a noninvasive optical neuroimaging method that is fully compatible with a CI and safe for repeated testing...
August 14, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28805877/a-dna-bipedal-nanowalker-with-a-piston-like-expulsion-stroke
#5
Q Y Yeo, I Y Loh, S R Tee, Y H Chiang, J Cheng, M H Liu, Z S Wang
Artificial molecular walkers beyond burn-bridge designs are important for nanotechnology, but their systematic development remains difficult. Herein, we have reported a new rationally designed DNA walker-track system and experimentally verified a previously proposed general expulsion regime for implementing non-burn-bridge nanowalkers. The DNA walker has an optically powered engine motif that reversibly extends and contracts the walker via a quadruplex-duplex conformational change. The walker's extension is an energy-absorbing and force-generating process, which drives the walker's leg dissociation off-track in a piston-like expulsion stroke...
August 14, 2017: Nanoscale
https://www.readbyqxmd.com/read/28803949/measuring-temporal-summation-in-visual-detection-with-a-single-photon-source
#6
Rebecca Holmes, Michelle Victora, Ranxiao Frances Wang, Paul G Kwiat
Temporal summation is an important feature of the visual system which combines visual signals that arrive at different times. Previous research estimated complete summation to last for 100 ms for stimuli judged "just detectable." We measured the full range of temporal summation for much weaker stimuli using a new paradigm and a novel light source, developed in the field of quantum optics for generating small numbers of photons with precise timing characteristics and reduced variance in photon number. Dark-adapted participants judged whether a light was presented to the left or right of their fixation in each trial...
August 10, 2017: Vision Research
https://www.readbyqxmd.com/read/28796755/the-effect-of-lumbar-disc-herniation-on-musculoskeletal-loadings-in-the-spinal-region-during-level-walking-and-stair-climbing
#7
Shengzheng Kuai, Zhenhua Liao, Wenyu Zhou, Xinyu Guan, Run Ji, Rui Zhang, Daiqi Guo, Weiqiang Liu
BACKGROUND People with low back pain (LBP) alter their motion patterns during level walking and stair climbing due to pain or fear. However, the alternations of load sharing during the two activities are largely unknown. The objective of this study was to investigate the effect of LBP caused by lumbar disc herniation (LDH) on the muscle activities of 17 main trunk muscle groups and the intradiscal forces acting on the five lumbar discs. MATERIAL AND METHODS Twenty-six healthy adults and seven LDH patients were recruited to perform level walking and stair climbing in the Gait Analysis Laboratory...
August 10, 2017: Medical Science Monitor: International Medical Journal of Experimental and Clinical Research
https://www.readbyqxmd.com/read/28791546/quantitative-analysis-of-photoreceptor-layer-reflectivity-on-en-face-optical-coherence-tomography-as-an-estimator-of-cone-density
#8
Maher Saleh, Mathieu Flores, Anne Sophie Gauthier, Emeric Elphege, Bernard Delbosc
BACKGROUND: To investigate whether outer retinal reflectivity on en-face Optical coherence tomography (OCT) can be considered as an estimator of cone density measured in the same area. METHODS: Forty-one points of comparisons were studied in 9 eyes (n = 6 patients) presenting maculopathies with various degrees of impairment of the photoreceptor layer. The inner segment ellipsoid zone (EZ), interdigitation zone (IZ), and retinal pigment epithelium (RPE) reflectivity were measured on coronal reconstruction of the photoreceptor layer using homemade dedicated software (Matlab, MathWorks Inc...
August 8, 2017: Graefe's Archive for Clinical and Experimental Ophthalmology
https://www.readbyqxmd.com/read/28791532/diameter-changes-of-retinal-vessels-in-diabetic-retinopathy
#9
REVIEW
Toke Bek
PURPOSE OF REVIEW: The diameter of retinal vessels is an important source of information about retinal blood flow and metabolism. The purpose of the present study is to review how diameter changes of retinal vessels contribute to the development of diabetic retinopathy and may be a marker of the prognosis of the disease. RECENT FINDINGS: The early stages of diabetic retinopathy are accompanied with dilatation of the diameter of retinal vessels and reduced autoregulation...
August 8, 2017: Current Diabetes Reports
https://www.readbyqxmd.com/read/28791156/mismatch-between-the-eye-and-the-optic-lobe-in-the-giant-squid
#10
Yung-Chieh Liu, Tsung-Han Liu, Chun-Chieh Yu, Chia-Hao Su, Chuan-Chin Chiao
Giant squids (Architeuthis) are a legendary species among the cephalopods. They live in the deep sea and are well known for their enormous body and giant eyes. It has been suggested that their giant eyes are not adapted for the detection of either mates or prey at distance, but rather are best suited for monitoring very large predators, such as sperm whales, at distances exceeding 120 m and at a depth below 600 m (Nilsson et al. 2012 Curr. Biol.22, 683-688. (doi:10.1016/j.cub.2012.02.031)). However, it is not clear how the brain of giant squids processes visual information...
July 2017: Royal Society Open Science
https://www.readbyqxmd.com/read/28781156/evaluation-of-deformed-image-based-dose-calculations-for-adaptive-radiotherapy-of-nasopharyngeal-carcinoma
#11
Miranda Poon, Catherine Holborn, Ka Fai Cheng, Winky Wing Ki Fung, George Chiu
The ultimate goal of adaptive radiotherapy (ART) is to deliver truly customized radiation treatments. Currently, the quality of cone-beam computed tomography (CBCT) images is still inferior to that of conventional CT images in contour delineations and dose calculations for replanning purposes. This retrospective study aims to evaluate the dosimetric accuracy of using deformed conventional CT images for dose calculations, in the hope of inferring the feasibility of ART using planning CT (PCT) images that deformed to up-to-date CBCT images for patients with nasopharyngeal carcinoma (NPC)...
August 3, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/28780099/effect-of-recombinant-bovine-somatotropin-on-leukocyte-mrna-expression-for-genes-related-to-cell-energy-metabolism-cytokine-production-phagocytosis-oxidative-burst-and-adaptive-immunity
#12
P R B Silva, C D Nelson, J P Driver, W W Thatcher, R C Chebel
Objectives of the current experiment were to evaluate the effects of treatment of periparturient dairy cows with recombinant bovine somatotropin (rbST) on mRNA expression in peripheral leukocytes for genes related to the somatotropic axis, cell energy metabolism, and innate and adaptive immune responses. Cows were enrolled in the experiment at 253 ± 3 d of gestation and assigned to an untreated control group (n = 98) or to receive 125 mg of rbST weekly from -21 to 21 d relative to calving (rbST125; n = 98)...
August 2, 2017: Journal of Dairy Science
https://www.readbyqxmd.com/read/28777341/a-multiscale-material-testing-system-for-in-situ-optical-and-electron-microscopes-and-its-application
#13
Xuan Ye, Zhiguo Cui, Huajun Fang, Xide Li
We report a novel material testing system (MTS) that uses hierarchical designs for in-situ mechanical characterization of multiscale materials. This MTS is adaptable for use in optical microscopes (OMs) and scanning electron microscopes (SEMs). The system consists of a microscale material testing module (m-MTM) and a nanoscale material testing module (n-MTM). The MTS can measure mechanical properties of materials with characteristic lengths ranging from millimeters to tens of nanometers, while load capacity can vary from several hundred micronewtons to several nanonewtons...
August 4, 2017: Sensors
https://www.readbyqxmd.com/read/28777323/a-3d-laser-profiling-system-for-rail-surface-defect-detection
#14
Zhimin Xiong, Qingquan Li, Qingzhou Mao, Qin Zou
Rail surface defects such as the abrasion, scratch and peeling often cause damages to the train wheels and rail bearings. An efficient and accurate detection of rail defects is of vital importance for the safety of railway transportation. In the past few decades, automatic rail defect detection has been studied; however, most developed methods use optic-imaging techniques to collect the rail surface data and are still suffering from a high false recognition rate. In this paper, a novel 3D laser profiling system (3D-LPS) is proposed, which integrates a laser scanner, odometer, inertial measurement unit (IMU) and global position system (GPS) to capture the rail surface profile data...
August 4, 2017: Sensors
https://www.readbyqxmd.com/read/28776029/genome-wide-signatures-of-complex-introgression-and-adaptive-evolution-in-the-big-cats
#15
Henrique V Figueiró, Gang Li, Fernanda J Trindade, Juliana Assis, Fabiano Pais, Gabriel Fernandes, Sarah H D Santos, Graham M Hughes, Aleksey Komissarov, Agostinho Antunes, Cristine S Trinca, Maíra R Rodrigues, Tyler Linderoth, Ke Bi, Leandro Silveira, Fernando C C Azevedo, Daniel Kantek, Emiliano Ramalho, Ricardo A Brassaloti, Priscilla M S Villela, Adauto L V Nunes, Rodrigo H F Teixeira, Ronaldo G Morato, Damian Loska, Patricia Saragüeta, Toni Gabaldón, Emma C Teeling, Stephen J O'Brien, Rasmus Nielsen, Luiz L Coutinho, Guilherme Oliveira, William J Murphy, Eduardo Eizirik
The great cats of the genus Panthera comprise a recent radiation whose evolutionary history is poorly understood. Their rapid diversification poses challenges to resolving their phylogeny while offering opportunities to investigate the historical dynamics of adaptive divergence. We report the sequence, de novo assembly, and annotation of the jaguar (Panthera onca) genome, a novel genome sequence for the leopard (Panthera pardus), and comparative analyses encompassing all living Panthera species. Demographic reconstructions indicated that all of these species have experienced variable episodes of population decline during the Pleistocene, ultimately leading to small effective sizes in present-day genomes...
July 2017: Science Advances
https://www.readbyqxmd.com/read/28773176/color-shift-failure-prediction-for-phosphor-converted-white-leds-by-modeling-features-of-spectral-power-distribution-with-a-nonlinear-filter-approach
#16
Jiajie Fan, Moumouni Guero Mohamed, Cheng Qian, Xuejun Fan, Guoqi Zhang, Michael Pecht
With the expanding application of light-emitting diodes (LEDs), the color quality of white LEDs has attracted much attention in several color-sensitive application fields, such as museum lighting, healthcare lighting and displays. Reliability concerns for white LEDs are changing from the luminous efficiency to color quality. However, most of the current available research on the reliability of LEDs is still focused on luminous flux depreciation rather than color shift failure. The spectral power distribution (SPD), defined as the radiant power distribution emitted by a light source at a range of visible wavelength, contains the most fundamental luminescence mechanisms of a light source...
July 18, 2017: Materials
https://www.readbyqxmd.com/read/28772457/model-stirrer-based-on-a-multi-material-turntable-for-microwave-processing-materials
#17
Jinghua Ye, Tao Hong, Yuanyuan Wu, Li Wu, Yinhong Liao, Huacheng Zhu, Yang Yang, Kama Huang
Microwaves have been widely used in the treatment of materials, such as heating, drying, and sterilization. However, the heating in the commonly used microwave applicators is usually uneven. In this paper, a novel multi-material turntable structure is creatively proposed to improve the temperature uniformity in microwave ovens. Three customized turntables consisting of polyethylene (PE) and alumina, PE and aluminum, and alumina and aluminum are, respectively, utilized in a domestic microwave oven in simulation...
January 24, 2017: Materials
https://www.readbyqxmd.com/read/28767059/hyperspectral-and-radar-airborne-imagery-over-controlled-release-of-oil-at-sea
#18
Sébastien Angelliaume, Xavier Ceamanos, Françoise Viallefont-Robinet, Rémi Baqué, Philippe Déliot, Véronique Miegebielle
Remote sensing techniques are commonly used by Oil and Gas companies to monitor hydrocarbon on the ocean surface. The interest lies not only in exploration but also in the monitoring of the maritime environment. Occurrence of natural seeps on the sea surface is a key indicator of the presence of mature source rock in the subsurface. These natural seeps, as well as the oil slicks, are commonly detected using radar sensors but the addition of optical imagery can deliver extra information such as thickness and composition of the detected oil, which is critical for both exploration purposes and efficient cleanup operations...
August 2, 2017: Sensors
https://www.readbyqxmd.com/read/28764500/note-a-four-pass-acousto-optic-modulator-system-for-laser-cooling-of-sodium-atoms
#19
Bo Lu, Dajun Wang
We present a four-pass acousto-optic modulator (AOM) system for providing the repumping light for laser cooling of sodium atoms. With only one 400 MHz AOM, we achieve a tunable laser frequency shift around 1.6 GHz with total efficiency up to 30%. This setup provides an alternative over conventional methods to generate a sodium repumping light using more expensive high frequency AOMs or electro-optical modulators (EOMs) in the GHz domain. This compact and reliable setup can be easily adapted to other frequencies and may find applications in laser spectroscopy, laser cooling and trapping, and coherent manipulation of atomic quantum states...
July 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28760978/superresolution-expansion-microscopy-reveals-the-three-dimensional-organization-of-the-drosophila-synaptonemal-complex
#20
Cori K Cahoon, Zulin Yu, Yongfu Wang, Fengli Guo, Jay R Unruh, Brian D Slaughter, R Scott Hawley
The synaptonemal complex (SC), a structure highly conserved from yeast to mammals, assembles between homologous chromosomes and is essential for accurate chromosome segregation at the first meiotic division. In Drosophila melanogaster, many SC components and their general positions within the complex have been dissected through a combination of genetic analyses, superresolution microscopy, and electron microscopy. Although these studies provide a 2D understanding of SC structure in Drosophila, the inability to optically resolve the minute distances between proteins in the complex has precluded its 3D characterization...
August 15, 2017: Proceedings of the National Academy of Sciences of the United States of America
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