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https://www.readbyqxmd.com/read/27913326/delay-and-standard-deviation-beamforming-to-enhance-specular-reflections-in-ultrasound-imaging
#1
Raja Sekhar Bandaru, Anders Rasmus Sornes, Jeroen Hermans, Eigil Samset, Jan D'hooge
Although interventional devices, such as needles, guide wires, and catheters, are best visualized by X-ray, real-time volumetric echography could offer an attractive alternative as it avoids ionizing radiation; it provides good soft tissue contrast, and it is mobile and relatively cheap. Unfortunately, as echography is traditionally used to image soft tissue and blood flow, the appearance of interventional devices in conventional ultrasound images remains relatively poor, which is a major obstacle toward ultrasound-guided interventions...
December 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27912115/self-assembled-hemispherical-nanowell-arrays-for-superhydrophobic-antireflection-coatings
#2
Cheng-Yen Lin, Kun-Yi Andrew Lin, Ting-Wei Yang, Ying-Chu Chen, Hongta Yang
The present study reports an inexpensive and simple bottom-up technology for fabricating superhydrophobic antireflection coatings with highly ordered hemispherical nanowell structures, which are assembled by a scalable Langmuir-Blodgett technology. The subwavelength gratings lead to a gradual change in the effective refractive index, substantially suppressing specular reflection over the entire visible wavelength range. After surface modification with fluorinated silane, the resulting nanowell arrays exhibit superhydrophobic surface with high static water contact angle (154°) and low water contact angle hysteresis (7°)...
November 21, 2016: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/27901088/tunable-microwave-metasurfaces-for-high-performance-operations-dispersion-compensation-and-dynamical-switch
#3
He-Xiu Xu, Shiwei Tang, Shaojie Ma, Weijie Luo, Tong Cai, Shulin Sun, Qiong He, Lei Zhou
Controlling the phase distributions on metasurfaces leads to fascinating effects such as anomalous light refraction/reflection, flat-lens focusing, and optics-vortex generation. However, metasurfaces realized so far largely reply on passive resonant meta-atoms, whose intrinsic dispersions limit such passive meta-devices' performances at frequencies other than the target one. Here, based on tunable meta-atoms with varactor diodes involved, we establish a scheme to resolve these issues for microwave metasurfaces, in which the dispersive response of each meta-atom is precisely controlled by an external voltage imparted on the diode...
November 30, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27899387/activation-of-cytomegalovirus-corneal-endotheliitis-following-laser-in-situ-keratomileusis
#4
Tien-En Tan, Chui Ming Gemmy Cheung, Jodhbir S Mehta
A case of Cytomegalovirus (CMV) corneal endotheliitis following laser in-situ keratomileusis (LASIK) is presented. A 32-year-old man presented 3 weeks after uncomplicated myopic LASIK with unilateral LASIK flap oedema, interface fluid accumulation, keratic precipitates, anterior uveitis and raised intraocular pressure. Despite treatment with topical corticosteroids, he had 3 further recurrent episodes. Specular microscopy showed decreased endothelial cell density and aqueous humour. Polymerase chain reaction (PCR) testing was positive for CMV DNA...
November 29, 2016: BMJ Case Reports
https://www.readbyqxmd.com/read/27893622/image-quality-and-artifacts-on-optical-coherence-tomography-angiography-comparison-of-pathologic-and-paired-fellow-eyes-in-65-patients-with-unilateral-choroidal-melanoma-treated-with-plaque-radiotherapy
#5
Emil A T Say, Sandor Ferenczy, George N Magrath, Wasim A Samara, Chloe T L Khoo, Carol L Shields
PURPOSE: To study image quality and artifacts seen on optical coherence tomography angiography (OCTA). METHODS: Sixty-five consecutive patients with unilateral posterior uveal melanoma treated with plaque radiotherapy had OCTA during follow-up. Optical coherence tomography angiography was performed on both the affected and fellow eye. Signal strength and frequency of image artifacts on en face images were compared between affected and fellow eyes. RESULTS: A total of 130 eyes in 65 patients were analyzed, the mean age at time of OCTA was 55 years (median: 56, range: 12-81 years), and 39 (39/65, 60%) were female...
November 23, 2016: Retina
https://www.readbyqxmd.com/read/27890511/cuticular-microstructures-turn-specular-black-into-matt-black-in-a-stick-insect
#6
Doris L Maurer, Tobias Kohl, Michael J Gebhardt
The stick insect Peruphasma schultei stands out from other insects by its deep matt black cuticle. We tested whether the appearance of P. schultei is due to microstructures of the cuticle, a phenomenon that has recently been described for the velvet black scales of the Gaboon viper. The shiny black stick insect Anisomorpha paromalus served as a control. We found that the P. schultei cuticle is characterised by two different types of microstructures, tall elevations with a maximum size of 18 μm and small structures with a height of 4 μm...
November 23, 2016: Arthropod Structure & Development
https://www.readbyqxmd.com/read/27886476/coexistence-of-quantized-time-dependent-clusters-in-globally-coupled-oscillators
#7
Hongjie Bi, Xin Hu, S Boccaletti, Xingang Wang, Yong Zou, Zonghua Liu, Shuguang Guan
We report on a novel collective state, occurring in globally coupled nonidentical oscillators in the proximity of the point where the transition from the system's incoherent to coherent phase converts from explosive to continuous. In such a state, the oscillators form quantized clusters, where neither their phases nor their instantaneous frequencies are locked. The oscillators' instantaneous speeds are different within the clusters, but they form a characteristic cusped pattern and, more importantly, they behave periodically in time so that their average values are the same...
November 11, 2016: Physical Review Letters
https://www.readbyqxmd.com/read/27884788/the-virtual-dissecting-room-creating-highly-detailed-anatomy-models-for-educational-purposes
#8
Marijn Zilverschoon, Koen L Vincken, Ronald L A W Bleys
INTRODUCTION: Virtual 3D models are powerful tools for teaching anatomy. At the present day, there are a lot of different digital anatomy models, most of these commercial applications are based on a 3D model of a human body reconstructed from images with a 1 millimeter intervals. The use of even smaller intervals may result in more details and more realistic appearances of 3D anatomy models. The aim of this study was to create a realistic and highly detailed 3D model of the hand and wrist based on small interval cross-sectional images, suitable for undergraduate and postgraduate teaching purposes with the possibility to perform a virtual dissection in an educational application...
November 21, 2016: Journal of Biomedical Informatics
https://www.readbyqxmd.com/read/27878429/comparison-of-specular-microscopy-and-ultrasound-pachymetry-before-and-after-cataract-surgery
#9
Alberto López-Miguel, María Sanchidrián, Itziar Fernández, Alfredo Holgueras, Miguel J Maldonado
PURPOSE: To compare specular microscopy (Topcon SP-3000P, Topcon Corporation, Tokyo, Japan) and ultrasound (US) technology when evaluating central corneal thickness (CCT) prior to and after phacoemulsification. METHODS: Corneal edema was assessed in phacoemulsification patients due to senile cataract by measuring CCT preoperatively and 1 day, 1 month, and 3 months postoperatively. Bland-Altman analysis was performed to assess interchangeability between pachymetry techniques for each visit...
November 22, 2016: Graefe's Archive for Clinical and Experimental Ophthalmology
https://www.readbyqxmd.com/read/27861306/enhancing-dmek-success-by-identifying-optimal-levels-of-trypan-blue-dye-application-to-donor-corneal-tissue
#10
Parag A Majmudar, Lauren Johnson
PURPOSE: The purpose of this study was to determine the correct concentration and duration of application of trypan blue dye to Descemet membrane endothelial keratoplasty (DMEK) donor corneal tissue before transplant to enhance visibility while minimizing damage to the tissue. METHODS: Corneas were precut for DMEK using an 8-mm punch, and each was stained with either 0.06% or 0.15% trypan blue for a duration of 1, 3, or 5 minutes. After staining, each tissue was placed in balanced salt solution and observed to determine how quickly the stain faded from the tissue using a grading system...
November 16, 2016: Cornea
https://www.readbyqxmd.com/read/27857330/planar-hyperblack-absolute-radiometer
#11
John Lehman, Andreas Steiger, Nathan Tomlin, Malcolm White, Mathias Kehrt, Ivan Ryger, Michelle Stephens, Christian Monte, Ingmar Mueller, Joerg Hollandt, Marla Dowell
The absolute responsivity of a planar cryogenic radiometer fabricated from micromachined silicon and having carbon nanotubes, as the absorber and thermistor were measured in the visible and far infrared (free-field terahertz) wavelength range by means of detector-based radiometry. The temperature coefficient of the thermistor near 4.8 K and noise equivalent power were evaluated along with independent characterization of the window transmittance and specular reflectance of the nanotube absorber. Measurements of absolute power by means of electrical substitution are compared to the German national standard and the uncertainty of the radiometer responsivity as a function of wavelength is summarized...
November 14, 2016: Optics Express
https://www.readbyqxmd.com/read/27856284/multiwavelength-micromirrors-in-the-cuticle-of-scarab-beetle-chrysina-gloriosa
#12
Gonzague Agez, Chloé Bayon, Michel Mitov
: Beetles from the genus Chrysina show vivid reflections from bright green to metallic silver-gold as a consequence of the cholesteric liquid crystal organization of chitin molecules. Particularly, the cuticle of Chrysina gloriosa exhibits green and silver stripes. By combining confocal microscopy and spectrophotometry, scanning electron microscopy and numerical simulations, the relationship between the reflectance and the structural parameters for both stripes at the micro- and nanoscales are established...
November 14, 2016: Acta Biomaterialia
https://www.readbyqxmd.com/read/27828377/wide-angled-off-axis-achromatic-metasurfaces-for-visible-light
#13
Zi-Lan Deng, Shuang Zhang, Guo Ping Wang
We present an approach to build multiwavelength achromatic metasurface that can work in off-axis configuration with an ultra-wide applicable incident angle range for visible light. The metasurface is constructed by combining multiple metallic nano-groove gratings, which support enhanced diffractions for transverse magnetic polarization in an ultrawide incident angle range from 10° to 80° due to the excitations of localized gap plasmon modes at different resonance wavelengths. To achieve the achromatic diffraction, the ratio between the resonance wavelength and the period of each elementary grating is fixed...
October 3, 2016: Optics Express
https://www.readbyqxmd.com/read/27827347/imaging-pulsed-laser-deposition-growth-of-homo-epitaxial-srtio3-by-low-energy-electron-microscopy
#14
A J H van der Torren, S J van der Molen, J Aarts
By combining low-energy electron microscopy with in situ pulsed laser deposition we have developed a new technique for film growth analysis, making use of both diffraction and real-space information. Working at the growth temperature, we can use: the intensity and profile variations of the specular beam to follow the coverage in a layer-by-layer fashion; real-space microscopy to follow e.g. atomic steps at the surface; and electron reflectivity to probe the unoccupied band structure of the grown material. Here, we demonstrate our methodology for homo-epitaxial growth of SrTiO3...
November 9, 2016: Nanotechnology
https://www.readbyqxmd.com/read/27824383/360-degree-iris-burns-following-conductive-keratoplasty
#15
Hanefi Çakir, Selim Genç, Emre Güler
PURPOSE: The authors report a case with multiple iris burns after conductive keratoplasty to correct hyperopia. METHODS: Case report. RESULTS: A 52-year-old woman with hyperopia had a previous conductive keratoplasty procedure and underwent a conductive keratoplasty re-treatment 6 months later. Postoperatively, she presented with 360-degree iris burns in both eyes that were correlated with the corneal conductive keratoplasty scars. In addition, specular microscopy revealed decreased endothelial cell density for both eyes...
November 1, 2016: Journal of Refractive Surgery
https://www.readbyqxmd.com/read/27794355/including-scattering-within-the-room-acoustics-diffusion-model-an-analytical-approach
#16
Cédric Foy, Judicaël Picaut, Vincent Valeau
Over the last 20 years, a statistical acoustic model has been developed to predict the reverberant sound field in buildings. This model is based on the assumption that the propagation of the reverberant sound field follows a transport process and, as an approximation, a diffusion process that can be easily solved numerically. This model, initially designed and validated for rooms with purely diffuse reflections, is extended in the present study to mixed reflections, with a proportion of specular and diffuse reflections defined by a scattering coefficient...
October 2016: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/27785456/gyroid-optical-metamaterials-calculating-the-effective-permittivity-of-multidomain-samples
#17
James A Dolan, Matthias Saba, Raphael Dehmel, Ilja Gunkel, Yibei Gu, Ulrich Wiesner, Ortwin Hess, Timothy D Wilkinson, Jeremy J Baumberg, Ullrich Steiner, Bodo D Wilts
Gold gyroid optical metamaterials are known to possess a reduced plasma frequency and linear dichroism imparted by their intricate subwavelength single gyroid morphology. The anisotropic optical properties are, however, only evident when a large individual gyroid domain is investigated. Multidomain gyroid metamaterials, fabricated using a polyisoprene-b-polystyrene-b-poly(ethylene oxide) triblock terpolymer and consisting of multiple small gyroid domains with random orientation and handedness, instead exhibit isotropic optical properties...
October 19, 2016: ACS Photonics
https://www.readbyqxmd.com/read/27776315/ir-atr-investigation-of-surface-anisotropy-in-silicate-glasses
#18
Vladimir Ivanovski, Thomas G Mayerhöfer, Antje Kriltz, Jürgen Popp
Several samples of flat soda-lime silicate glass were investigated by the Infrared Attenuated Total Reflection (IR-ATR) spectroscopy technique. The specular reflectance spectra together with the results of the performed dispersion analysis and the generated reflectance spectra, using Fresnel equations, suggest that the samples are isotropic. In contrast, spectra recorded by the ATR technique suggest an anisotropic structure on the surface of the specimen different from that in the bulk. This is established through differences in the s- and p-polarized IR-ATR spectra, which cannot be simply transformed into one another employing Fresnel formula for an isotropic case...
October 17, 2016: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/27774454/computer-based-melanocytic-and-nevus-image-enhancement-and-segmentation
#19
Uzma Jamil, M Usman Akram, Shehzad Khalid, Sarmad Abbas, Kashif Saleem
Digital dermoscopy aids dermatologists in monitoring potentially cancerous skin lesions. Melanoma is the 5th common form of skin cancer that is rare but the most dangerous. Melanoma is curable if it is detected at an early stage. Automated segmentation of cancerous lesion from normal skin is the most critical yet tricky part in computerized lesion detection and classification. The effectiveness and accuracy of lesion classification are critically dependent on the quality of lesion segmentation. In this paper, we have proposed a novel approach that can automatically preprocess the image and then segment the lesion...
2016: BioMed Research International
https://www.readbyqxmd.com/read/27769461/quantitative-analysis-of-solid-samples-using-modified-specular-reflectance-accessory
#20
Tomasz Czaja, Sylwester Mazurek, Roman Szostak
Diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS) is a fast, reliable and cost effective analytical method, requiring minimal or no sample preparation. It is commonly used in the course of qualitative and quantitative analysis of pharmaceutical ingredients and food. We demonstrate that simpler and cheaper specular reflectance (SR) accessory working in a DRIFTS like mode (SR-DL) can be an alternative for DIRFTS attachment. An application of a modified SR accessory for quantitative analysis of solids samples is presented...
December 1, 2016: Talanta
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