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Adaptive optics

P Monsalve, S Ren, G Triolo, L Vazquez, A D Henderson, M Kostic, P Gordon, W J Feuer, V Porciatti
PURPOSE: To investigate within-test variability of the steady-state PERG (SS-PERG). METHODS: SS-PERGs were recorded in response to black-white horizontal gratings (1.6 cycles/deg, 98% contrast, 15.63 reversals/s, LED display, 25 deg square field, 800 cd/sqm mean luminance) using skin electrodes. PERG and noise (± reference) signals were averaged over 1024 epochs (~ 2.2 min) and Fourier analyzed to retrieve SS-PERG amplitude and phase. SS-PERGs were split into 16 partial averages (samples) of 64 epochs each, and corresponding amplitudes and phases combined in polar coordinates to assess their dispersion (within-test variability)...
May 19, 2018: Documenta Ophthalmologica. Advances in Ophthalmology
H Fayad, M Gilles, T Pan, D Visvikis
PURPOSE: Respiratory motion reduces the sensitivity and specificity of medical images especially in the thoracic and abdominal areas. It may affect applications such as cancer diagnostic imaging and/or radiation therapy (RT). Solutions to this issue include modelling of the respiratory motion in order to optimize both diagnostic and therapeutic protocols. Personalised motion modeling required patient specific four dimensional (4D) imaging which in the case of 4D computed tomography (4D CT) acquisition is associated with an increased dose...
May 17, 2018: Medical Physics
Yushu Liu, Hongqiang Ye, Yong Wang, Yijao Zhao, Yuchun Sun, Yongsheng Zhou
PURPOSE: To evaluate the internal adaptations of cast crowns made from resin patterns produced using three different computer-aided design/computer-assisted manufacturing technologies. MATERIALS AND METHODS: A full-crown abutment made of zirconia was digitized using an intraoral scanner, and the design of the crown was finished on the digital model. Resin patterns were fabricated using a fused deposition modeling (FDM) 3D printer (LT group), a digital light projection (DLP) 3D printer (EV group), or a five-axis milling machine (ZT group)...
May 17, 2018: International Journal of Prosthodontics
Yun Liu, Jesse Roll, Stephen Van Kooten, Xinyan Deng
The aerodynamic force on flying insects results from the vortical flow structures that vary both spatially and temporally throughout flight. Due to these complexities and the inherent difficulties in studying flying insects in a natural setting, a complete picture of the vortical flow has been difficult to obtain experimentally. In this paper, Schlieren , a widely used technique for highspeed flow visualization, was adapted to capture the vortex structures around freely flying hawkmoth ( Manduca ). Flow features such as leading-edge vortex, trailing-edge vortex, as well as the full vortex system in the wake were visualized directly...
May 2018: Biology Letters
Leonard Bezinge, Richard M Maceiczyk, Ioannis Lignos, Maksym V Kovalenko, Andrew J deMello
Recent advances in the development of hybrid organic-inorganic lead halide perovskite (LHP) nanocrystals (NCs) have demonstrated their versatility and potential application as photovoltaics and light emitters through compositional tuning of optical properties. That said, due to their compositional complexity, the targeted synthesis of mixed-cation, mixed-halide LHP NCs still represents an immense challenge for traditional batch scale chemistry. To address this limitation, we herein report the integration of a high-throughput segmented-flow microfluidic reactor and self-optimizing algorithm for the synthesis of nanocrystals with defined emission properties...
May 16, 2018: ACS Applied Materials & Interfaces
Da Yang, Anna D Jennings, Evalynn Borrego, Scott T Retterer, Jaan Männik
The microfluidic mother machine platform has attracted much interest for its potential in studies of bacterial physiology, cellular organization, and cell mechanics. Despite numerous experiments and development of dedicated analysis software, differences in bacterial growth and morphology in narrow mother machine channels compared to typical liquid media conditions have not been systematically characterized. Here we determine changes in E. coli growth rates and cell dimensions in different sized dead-end microfluidic channels using high resolution optical microscopy...
2018: Frontiers in Microbiology
Anna-Maria Marbà-Ardébol, Jörn Emmerich, Michael Muthig, Peter Neubauer, Stefan Junne
BACKGROUND: The morphology of yeast cells changes during budding, depending on the growth rate and cultivation conditions. A photo-optical microscope was adapted and used to observe such morphological changes of individual cells directly in the cell suspension. In order to obtain statistically representative samples of the population without the influence of sampling, in situ microscopy (ISM) was applied in the different phases of a Saccharomyces cerevisiae batch cultivation. The real-time measurement was performed by coupling a photo-optical probe to an automated image analysis based on a neural network approach...
May 15, 2018: Microbial Cell Factories
Elisabeth Dursun, Aude Monnier-Da Costa, Christian Moussally
After pulp therapy or with multi-surface caries in primary molars, pre-formed stainless steel crowns are usually placed to ensure tooth longevity. Esthetic alternatives, such as zirconia crowns, have been proposed, but they are invasive. Here we describe two cases of chairside computer-aided design and computer-aided manufacturing (CAD/CAM) technology used to treat extended and/or deep caries on primary molars. A powder-free chairside CAD/CAM system, a milling unit and machinable high-performance composite blocks were used...
May 15, 2018: Journal of Clinical Pediatric Dentistry
Bingyao Tan, Alexander Wong, Kostadinka Bizheva
A novel image processing algorithm based on a modified Bayesian residual transform (MBRT) was developed for the enhancement of morphological and vascular features in optical coherence tomography (OCT) and OCT angiography (OCTA) images. The MBRT algorithm decomposes the original OCT image into multiple residual images, where each image presents information at a unique scale. Scale selective residual adaptation is used subsequently to enhance morphological features of interest, such as blood vessels and tissue layers, and to suppress irrelevant image features such as noise and motion artefacts...
May 1, 2018: Biomedical Optics Express
Site Luo, Dan Wang, Jianyu Tang, Liang Zhou, Can Duan, Donglin Wang, Hao Liu, Yu Zhu, Guoxing Li, Hui Zhao, Yuqing Wu, Xin An, Xinling Li, Yabing Liu, Li Huo, Huikai Xie
We present a novel circumferential-scan endoscopic optical coherence tomography (OCT) probe by using a circular array of six electrothermal microelectromechanical (MEMS) mirrors and six C-lenses. The MEMS mirrors have a 0.5 mm × 0.5 mm mirror plate and a chip size of 1.5 mm × 1.3 mm. Each MEMS mirror can scan up to 45° at a voltage of less than 12 V. Six of those mirrors have been successfully packaged to a probe head; full circumferential scans have been demonstrated. Furthermore, each scan unit is composed of a MEMS mirror and a C-lens and the six scan units can be designed with different focal lengths to adapt for lesions with uneven surfaces...
May 1, 2018: Biomedical Optics Express
Anett Karl, Silke Agte, Astrid Zayas-Santiago, Felix N Makarov, Yomarie Rivera, Jan Benedikt, Mike Francke, Andreas Reichenbach, Serguei N Skatchkov, Andreas Bringmann
It has been shown that mammalian retinal glial (Müller) cells act as living optical fibers that guide the light through the retinal tissue to the photoreceptor cells (Agte et al., 2011; Franze et al., 2007). However, for nonmammalian species it is unclear whether Müller cells also improve the transretinal light transmission. Furthermore, for nonmammalian species there is a lack of ultrastructural data of the retinal cells, which, in general, delivers fundamental information of the retinal function, i.e. the vision of the species...
May 10, 2018: Experimental Eye Research
Kyung-Hoon Han, Young-Sam Park, Doo-Hee Cho, Yoonjay Han, Jonghee Lee, Byoung-Gon Yu, Nam Sung Cho, Jeong-Ik Lee, Jang-Joo Kim
Recently, we have addressed that a formation mechanism of a nano-lens array (NLA) fabricated by using a maskless vacuum deposition is explained as the increase in surface tension of organic molecules induced by their crystallization. Here, as another research using finite difference time domain (FDTD) simulations, not electric field intensities but transmitted energies of electromagnetic waves inside and outside top-emitting blue organic light emitting diodes (TOLEDs), without and with NLAs, are obtained, to easily grasp the effect of NLA formation on the light extraction of TOLEDs...
May 11, 2018: ACS Applied Materials & Interfaces
Ji Qi, Chao Chen, Xiaoyan Zhang, Xianglong Hu, Shenglu Ji, Ryan T K Kwok, Jacky W Y Lam, Dan Ding, Ben Zhong Tang
Fluorescence and photoacoustic imaging have different advantages in cancer diagnosis; however, combining effects in one agent normally requires a trade-off as the mechanisms interfere. Here, based on rational molecular design, we introduce a smart organic nanoparticle whose absorbed excitation energy can be photo-switched to the pathway of thermal deactivation for photoacoustic imaging, or to allow opposed routes for fluorescence imaging and photodynamic therapy. The molecule is made of a dithienylethene (DTE) core with two surrounding 2-(1-(4-(1,2,2-triphenylvinyl)phenyl)ethylidene)malononitrile (TPECM) units (DTE-TPECM)...
May 10, 2018: Nature Communications
Xinrong Cao, Lanyan Xue, Jiawen Lin, Lun Yu
Fast optic disk localization and boundary segmentation is an important research topic in computer aided diagnosis. This paper proposes a novel method to effectively segment optic disk by using human visual characteristics in analyzing and processing fundus image. After a general analysis of optic disk features in fundus images, the target of interest could be located quickly, and intensity, color and spatial distribution of the disc are used to generate saliency map based on pixel distance. Then the adaptive threshold is used to segment optic disk...
April 1, 2018: Sheng Wu Yi Xue Gong Cheng Xue za Zhi, Journal of Biomedical Engineering, Shengwu Yixue Gongchengxue Zazhi
Xiao Wu Xu, Xin Xiao Yu, Guo Dong Jia, Han Zhi Li, Wei Wei Lu, Zi Qiang Liu
Soil-vegetation-atmosphere continuum (SPAC) is one of the important research objects in the field of terrestrial hydrology, ecology and global change. The process of water and carbon cycling, and their coupling mechanism are frontier issues. With characteristics of tracing, integration and indication, stable isotope techniques contribute to the estimation of the relationship between carbon sequestration and water consumption in ecosystems. In this review, based on a brief introduction of stable isotope principles and techniques, the applications of stable isotope techniques to water and carbon exchange in SPAC using optical stable isotope techniques were mainly explained, including: partitioning of net carbon exchange into photosynthesis and respiration; partitioning of evapotranspiration into transpiration and evaporation; coupling of water and carbon cycle at the ecosystem scale...
July 18, 2017: Ying Yong Sheng Tai Xue Bao, the Journal of Applied Ecology
Chuanrui Chen, Songsong Tang, Hazhir Teymourian, Emil Karshalev, Fangyu Zhang, Jinxing Li, Fangzhi Mou, Yuyan Liang, Jianguo Guan, Joseph Wang
Hybrid micromotors capable of both chemically-powered propulsion and fuel-free light-driven actuation and offering built-in optical brakes for chemical propulsion are described. The new hybrid micromotors are designed by combining photocatalytic TiO2 and catalytic Pt surfaces into a Janus microparticle. The chemical reactions on the different surfaces of the Janus particle hybrid micromotor can be tailored by using chemical or light stimuli that generate counteracting propulsion forces on the catalytic Pt and photocatalytic TiO2 sides, respectively...
May 7, 2018: Angewandte Chemie
Zhuoqiong Ren, Yaou Liu, Kuncheng Li, Yunyun Duan, Huang Jing, Peipeng Liang, Zheng Sun, Xiaojun Zhang, Bei Mao
Purpose : To investigate spontaneous brain activity amplitude alterations in single and relapsing optic neuritis (sON and rON, respectively) and their relationships with clinical variables. Methods : In total, 42 patients with sON, 35 patients with rON and 50 healthy volunteers were recruited. Resting-state functional Magnetic Resonance Imaging (rs-fMRI) scans were acquired for all participants and compared to investigate the changes in the amplitude of low-frequency fluctuations (ALFFs) among the three groups...
2018: Frontiers in Human Neuroscience
Amit Nativ, Haim Feldman, Natan T Shaked
We present a system that is based on a new external, polarization-insensitive differential interference contrast (DIC) module specifically adapted for detecting defects in semiconductor wafers. We obtained defect signal enhancement relative to the surrounding wafer pattern when compared with bright-field imaging. The new DIC module proposed is based on a shearing interferometer that connects externally at the output port of an optical microscope and enables imaging thin samples, such as wafer defects. This module does not require polarization optics (such as Wollaston or Nomarski prisms) and is insensitive to polarization, unlike traditional DIC techniques...
May 1, 2018: Applied Optics
Tao Cheng, WenJin Liu, KangJian Yang, Xin He, Ping Yang, Bing Xu
It is well known that using two or more deformable mirrors (DMs) can improve the compensation ability of an adaptive optics (AO) system. However, to keep the stability of an AO system, the correlation between the multiple DMs must be suppressed during the correction. In this paper, we proposed a slope-based decoupling algorithm to simultaneous control the multiple DMs. In order to examine the validity and practicality of this algorithm, a typical woofer-tweeter (W-T) AO system was set up. For the W-T system, a theory model was simulated and the results indicated in theory that the algorithm we presented can selectively make woofer and tweeter correct different spatial frequency aberration and suppress the cross coupling between the dual DMs...
May 1, 2018: Applied Optics
Rohit Abraham John, Fucai Liu, Nguyen Anh Chien, Mohit R Kulkarni, Chao Zhu, Qundong Fu, Arindam Basu, Zheng Liu, Nripan Mathews
Emulation of brain-like signal processing with thin-film devices can lay the foundation for building artificially intelligent learning circuitry in future. Encompassing higher functionalities into single artificial neural elements will allow the development of robust neuromorphic circuitry emulating biological adaptation mechanisms with drastically lesser neural elements, mitigating strict process challenges and high circuit density requirements necessary to match the computational complexity of the human brain...
May 4, 2018: Advanced Materials
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