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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
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
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
Amani E Badawi
PURPOSE: The purpose of this study was to evaluate the effects of accelerated cross-linking (CXL) on corneal endothelium in keratoconus and postlaser-assisted in situ keratomileusis (LASIK) ectasia. DESIGN: This study is a prospective nonrandomized controlled study. SETTING: This study was conducted in Mansoura Ophthalmic Center (Mansoura University) and Al-Mostakbal Ophthalmic Center, Mansoura, Egypt. METHODS: In total, 40 eyes with progressive keratoconus and 10 eyes with postLASIK ectasia were subjected to an accelerated CXL (10 mW/cm(2) for 9 minutes)...
2016: Clinical Ophthalmology
Jia Xu, Zuzhen Huang, Liang Yan, Xu Zhou, Furu Zhang, Teng Long
For modern synthetic aperture radar (SAR), it has much more urgent demands on ground moving target indication (GMTI), which includes not only the point moving targets like cars, truck or tanks but also the distributed moving targets like river or ocean surfaces. Among the existing GMTI methods, displaced phase center antenna (DPCA) can effectively cancel the strong ground clutter and has been widely used. However, its detection performance is closely related to the target's signal-to-clutter ratio (SCR) as well as radial velocity, and it cannot effectively detect the weak large-sized river surfaces in strong ground clutter due to their low SCR caused by specular scattering...
October 12, 2016: Sensors
Uri Elbaz, Kamiar Mireskandari, Nasrin Tehrani, Carl Shen, Saad Khan, Sara Luck, Asim Ali
PURPOSE: To establish a normative database of endothelial cell density (ECD) using in-vivo specular microscopy in children under 5 years old. DESIGN: Cross sectional study. METHODS: Specular microscopy was performed during a clinic visit in cooperative children in the standard upright position. In uncooperative children, specular microscopy was performed in the lateral decubitus position under general anesthesia, prior to surgery for other reasons...
October 13, 2016: American Journal of Ophthalmology
Zachary M Mayko, Beth Ann Benetz, Harry Menegay, Christopher P Donovan, Christopher G Stoeger, Mark A Terry, Jonathan H Lass
PURPOSE: To evaluate a single eye bank's measurement of endothelial cell density (ECD) of Descemet membrane endothelial keratoplasty (DMEK) grafts before and after preparation using 2 separate counting methods. METHODS: A series of 60 donor tissues were prepared for DMEK surgery. One to 4 specular images of the central endothelium were taken both before and after preparation, and ECDs were evaluated for a total of 345 unique images. Images were then masked and provided to the Cornea Image Analysis Reading Center (CIARC) for independent analysis...
October 12, 2016: Cornea
Christophe Panthier, Romain Courtin, Emmanuel Guilbert, Damien Gatinel, Alain Saad
PURPOSE: To evaluate the clinical impact of implanting donor tissue torn during preparation for the Descemet membrane endothelial keratoplasty procedure. METHODS: In this single-center retrospective analysis of consecutive cases, 10 cases with torn donor tissue from one surgeon's caseload of 175 procedures were analyzed and compared with control cases. Best-corrected visual acuity, endothelial cell density of the donor tissue measured by specular microscopy, and the recipient's central corneal thickness were recorded preoperatively and again 1, 3, and 6 months after surgery...
October 12, 2016: Cornea
K M Ratheesh, L K Seah, V M Murukeshan
The automatic calibration in Fourier-domain optical coherence tomography (FD-OCT) systems allows for high resolution imaging with precise depth ranging functionality in many complex imaging scenarios, such as microsurgery. However, the accuracy and speed of the existing automatic schemes are limited due to the functional approximations and iterative operations used in their procedures. In this paper, we present a new real-time automatic calibration scheme for swept source-based optical coherence tomography (SS-OCT) systems...
October 14, 2016: Physics in Medicine and Biology
Juno Kim, Phillip J Marlow
Specular surfaces and refractive media are difficult to distinguish from each other because they both generate distorted images of the surrounding lighting environment. Whereas convex refractive objects invert the orientation of the horizon so the sky appears beneath the ground plane, convex specular surfaces preserve the orientation of the horizon so the sky appears above the ground. Here, we show that a refractive transparent object can be made to appear specular and opaque simply by rotating the image by 180°...
September 2016: I-Perception
Scott MacRae, Jack T Holladay, Gene Hilmantel, Don Calogero, Samuel Masket, Walter Stark, Adrian Glasser, Eva Rorer, Michelle E Tarver, Tieuvi Nguyen, Malvina Eydelman
No abstract text is available yet for this article.
October 7, 2016: Ophthalmology
Remzi Karadag, Murat Unluzeybek, Ozgur Cakici, Ayse Yagmur Kanra, Huseyin Bayramlar
AIM: The aim of the study is to compare the measurements of central corneal thickness (CCT) performed by two examiners with four different methods at different times inter- and intra-individually. METHODS: Thirty healthy people were included in the study. In these measurements, an optical low-coherence reflectometry (OLCR), an optic coherence tomography (OCT), a specular microscopy (SM), and a corneal topography (CT) were used. Two examiners performed the measurements in a consecutive manner...
October 8, 2016: International Ophthalmology
William Rock, Muhammed Enes Oruc, Ross J Ellis, Ahmet Uysal
Many industrial and biological processes involve the competitive adsorption of ions with different valencies and sizes at charged surfaces; heavy and precious metal ions are separated based on their propensity to adsorb onto interfaces, often as anionic ion clusters (e.g. [MClx](n-)). However, very little is known, both theoretically and experimentally, about the competition of factors that drive preferential adsorption, such as charge density or valence, at interfaces in technologically-relevant systems. There are even contradictory pictures described by interfacial studies and real life applications, such as chlorometallate extractions, where charge diffuse chlorometallate ions are extracted efficiently even though charge dense chloride ions present in the background are expected to occupy the interface...
October 7, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Mahmood Nejabat, Fatemeh Heidary, Mohammad Reza Talebnejad, Ramin Salouti, Mohammad Hossein Nowroozzadeh, Masoumeh Masoumpour, Hamideh Mahdaviazad, Zahra Tajbakhsh, Maryam Keshtkar, Hossein Jamali, Mohammad Reza Khalili, Hossein Movahedan, Narges Roustaei, Reza Gharebaghi
INTRODUCTION: This study aimed to determine intraocular pressure (IOP) and central corneal thickness (CCT) measurements in healthy Persian children to find clinical reference values in this ethnicity. Additionally, we examined the possible relationship between these measurements. METHODS: This cross-sectional study included 262 eyes of 131 Persian primary school children between 6 and 13 years of age. All eyes were healthy and had no anterior or posterior segment abnormalities, corneal disease, or evidence of glaucoma...
October 5, 2016: Ophthalmology and Therapy
Juno Kim, Kairen Tan, Nahian S Chowdhury
We experience vivid percepts of objects and materials despite complexities in the way images are structured by the interaction of light with surface properties (3D shape, albedo, and gloss or specularity). Although the perception of gloss (and lightness) has been argued to depend on image statistics (e.g., sub-band skew), studies have shown that perceived gloss depends critically on the structure of luminance variations in images. Here, we found that separately adapting observers to either positive or negative skew generated declines in perceived gloss, contrary to the predictions of theories involving image statistics...
July 2016: I-Perception
Yuan Zeng, Jian-Hua Gao
OBJECTIVE: This study aimed to evaluate the effect of Mydrin eye-drops on central corneal thickness values and investigate the duration of the effect. METHODS: In this prospective randomised self-controlled study, we enrolled 60 myopic patients (120 eyes) undergoing corneal laser refractive surgery. The central corneal thickness was measured before and one and four hours after administration of Mydrin eye-drops (major components are tropicamide and phenylephrine hydrochloride) using the Orbscan II anterior segment analysis system and a SP-2000P non-contact specular microscope, respectively...
September 29, 2016: Clinical & Experimental Optometry: Journal of the Australian Optometrical Association
Stefan Hellebrandt, Sang Soo Lee, Karah E Knope, Aaron J Lussier, Joanne E Stubbs, Peter J Eng, L Soderholm, Paul Fenter, Moritz Schmidt
X-ray scattering techniques [in situ resonant anomalous X-ray reflectivity (RAXR) and specular crystal truncation rods (CTR)] were used to compare muscovite (001) surfaces in contact with solutions containing either 0.1 mM plutonyl(VI) or 1 mM uranyl(VI) at pH = 3.2 ± 0.2, I(NaCl) = 0.1 M, as well as in situ grazing-incidence X-ray absorption near-edge structure (GI XANES) spectroscopy and ex situ alpha spectrometry. Details of the surface coverage are found to be very different. In the case of Pu, alpha spectrometry finds a surface coverage of 8...
October 10, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
R Sundar, K Ranganathan, P Hedaoo, K S Bindra
In this paper, we present a comparative study on pump heads for a high power diode-side-pumped Nd:YAG laser. The pump head is a modular type, which is in the form of discs, with each disc holding three pump diodes kept at 120° with respect to each other. Unabsorbed pump light from the active medium is reflected by reflectors mounted adjacent to the pump diodes. The performance of a high power pump head made of modular discs mounted with specular or diffused type reflectors was studied. Hybrid pump geometry was also investigated, where the pump head is made up of discs loaded with metal and diffused reflectors, alternately...
September 20, 2016: Applied Optics
Han Shi, Dong Du, JianFeng Xu, William W Moses, Qiyu Peng
Optical simulation of the detector module level is highly desired for Position Emission Tomography (PET) system design. Commonly used simulation toolkits such as GATE are not efficient in the optical simulation of detector modules with complicated light-sharing configurations, where a vast amount of photons need to be tracked. We present a fast approach based on a simplified specular reflectance model and a structured light-tracking algorithm to speed up the photon tracking in detector modules constructed with polished finish and specular reflector materials...
December 1, 2015: Nuclear Instruments & Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment
Yan Yan, Long Li, Guodong Xie, Changjing Bao, Peicheng Liao, Hao Huang, Yongxiong Ren, Nisar Ahmed, Zhe Zhao, Zhe Wang, Nima Ashrafi, Solyman Ashrafi, Shilpa Talwar, Soji Sajuyigbe, Moshe Tur, Andreas F Molisch, Alan E Willner
Electromagnetic waves carrying orbital angular momentum (OAM) have been used for mode division multiplexing in free-space communication systems to increase both the capacity and the spectral efficiency. In the case of conventional wireless communication links using non-OAM beams, multipath effects caused by beam spreading and reflection from the surrounding objects affect the system performance. This paper presents the results of analysis, simulations, and measurements of multipath effects in a millimetre-wave communication link using OAM multiplexing at 28 GHz...
2016: Scientific Reports
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