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Ronak Gupta, Meheboob Alam
The nature of particle-wall interactions is shown to have a profound impact on the well-known "Knudsen paradox" [or the "Knudsen minimum" effect, which refers to the decrease of the mass-flow rate of a gas with increasing Knudsen number Kn, reaching a minimum at Kn∼O(1) and increasing logarithmically with Kn as Kn→∞] in the acceleration-driven Poiseuille flow of rarefied gases. The nonmonotonic variation of the flow rate with Kn occurs even in a granular or dissipative gas in contact with thermal walls...
January 2018: Physical Review. E
Ebru N Cetin, Selda Sayın Kutlu, Osman Parca, Murat Kutlu, Gökhan Pekel
OBJECTIVES: To evaluate corneal and anterior chamber morphology as measured by Pentacam HR in human immunodeficiency virus (HIV)-infected patients without opportunistic infections and to search for signs of accelerated aging. METHODS: This prospective study included 41 eyes of 41 HIV-1-infected patients (study group) and 50 eyes of 50 healthy subjects (control group). Specular microscope and Pentacam HR were used for corneal and anterior chamber morphology evaluation...
February 12, 2018: Eye & Contact Lens
Alexander C Lygo, Danielle M Hamann, Daniel B Moore, Devin R Merrill, Jeffrey Ditto, Marco Esters, Jacob Orlowicz, Suzannah R Wood, David C Johnson
Preparing homologous series of compounds allows chemists to rapidly discover new compounds with predictable structure and properties. Synthesizing compounds within such a series involves navigating a free energy landscape defined by the interactions within and between constituent atoms. Historically, synthesis approaches are typically limited to forming only the most thermodynamically stable compound under the reaction conditions. Presented here is the synthesis, via self-assembly of designed precursors, of isocompositional incommensurate layered compounds [(BiSe)1+δ]m[TiSe2]m with m =1, 2, and 3...
February 12, 2018: Journal of the American Chemical Society
Christopher T Lam, Jenna Mueller, Betsy Asma, Mercy Asiedu, Marlee S Krieger, Rhea Chitalia, Denali Dahl, Peyton Taylor, John W Schmitt, Nimmi Ramanujam
INTRODUCTION: We have previously developed a portable Pocket Colposcope for cervical cancer screening in resource-limited settings. In this manuscript we report two different strategies (cross-polarization and an integrated reflector) to improve image contrast levels achieved with the Pocket Colposcope and evaluate the merits of each strategy compared to a standard-of-care digital colposcope. The desired outcomes included reduced specular reflection (glare), increased illumination beam pattern uniformity, and reduced electrical power budget...
2018: PloS One
Tiffany Sara Liu, Seth Meskin
The purpose of the study was to report a case of focal trichiasis causing full-thickness corneal edema, scarring, and endothelial cell loss requiring penetrating keratoplasty (PK). A 66-year-old male was referred for trichiasis of the right upper eyelid corresponding to an area of full-thickness corneal edema. No keratic precipitates or guttata was noted. Specular microscopy showed diffuse endothelial cell loss. He was treated with topical steroids and acyclovir with epilation of lashes. Anterior chamber paracentesis was negative for varicella-zoster virus, cytomegalovirus, and herpes simplex virus...
October 2017: Middle East African Journal of Ophthalmology
Pramod Kumar Sahu, Gopal Krushna Das, Sumeet Agrawal, Sabitabh Kumar, Nitish Kumar
PURPOSE: To determine if phacoemulsification with intraocular lens implantation has a greater impact on the corneal endothelium of type 2 diabetic patients as compared to nondiabetics. MATERIALS AND METHODS: This study compared the endothelial status in 60 diabetics with good glycemic control and 60 nondiabetics before and after uneventful phacoemulsification. Central corneal endothelial cell density, percentage hexagonality and percentage coefficient of variation (%CV) were measured using a specular microscope...
October 2017: Middle East African Journal of Ophthalmology
Raffael Rameshan, Vedran Vonk, Dirk Franz, Jakub Drnec, Simon Penner, Andreas Garhofer, Florian Mittendorfer, Andreas Stierle, Bernhard Klötzer
Surface X-ray Diffraction was used to study the transformation of a carbon-supersaturated carbidic precursor toward a complete single layer of graphene in the temperature region below 703 K without carbon supply from the gas phase. The excess carbon beyond the 0.45  monolayers of C atoms within a single Ni2C layer is accompanied by sharpened reflections of the |4772| superstructure, along with ring-like diffraction features resulting from non-coincidence rotated Ni2C-type domains. A dynamic Ni2C reordering process, accompanied by slow carbon loss to subsurface regions, is proposed to increase the Ni2C 2D carbide long-range order via ripening toward coherent domains, and to increase the local supersaturation of near-surface dissolved carbon required for spontaneous graphene nucleation and growth...
February 8, 2018: Scientific Reports
Yumi Takashina, Terumasa Mitogawa, Kota Saito, Katsuyoshi Hoshino
Metal-free, metal-like lustrous films may find applications in a variety of fields, and a study of the factors affecting their stability is highly desirable. In particular, chemical events occurring in the coating solutions might affect the supramolecular organization of the films and therefore the metal-like luster. Herein, the chemical events occurring in acetonitrile and nitromethane coating solutions of oligo(3-methoxythiophene) and their effect on the optical properties of the films were investigated by X-ray diffraction, UV-vis absorption, and viscosity measurements...
February 8, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Jagdish A K, Kavita Garg, Praveen C Ramamurthy, Debiprosad Roy Mahapatra, Gopalkrishna Hegde
Nano-scale patterns such as those found on the exterior surface of the eyes of certain nocturnal insects have far-reaching implications in terms of optoelectronic device design. The advantage of using these patterns for optoelectronic enhancement in photovoltaic light harvesting has been less explored due to the lack of suitable engineered materials to easily fabricate such nanostructures. Here, an attempt is made to realize these complex patterns using a self-assembly based molding process on hitherto unexplored robust structural epoxies with excellent repeatability and scalability to a larger area...
February 7, 2018: Nanoscale
Takashi Ono, Masaharu Iida, Toshihiro Sakisaka, Keiichiro Minami, Kazunori Miyata
PURPOSE: To evaluate the changes in corneal endothelial cell density (ECD) over a 7-year period after laser peripheral iridotomy (LPI) using argon and neodymium-doped yttrium aluminum garnet (Nd:YAG) lasers. STUDY DESIGN: Retrospective case series. METHODS: Eyes that underwent prophylactic LPI using argon and Nd:YAG lasers were followed up for 7 years. Central corneal endothelial cells were observed by use of noncontact specular microscopy preoperatively and at 1 and 7 years postoperatively...
February 6, 2018: Japanese Journal of Ophthalmology
Zhenqi Niu, Nan Gao, Zonghua Zhang, Feng Gao, Xiangqian Jiang
This paper presents an advanced phase measuring deflectometry (PMD) method based on a novel mathematical model to obtain three dimensional (3D) shape of discontinuous specular object using a bi-telecentric lens. The proposed method uses an LCD screen, a flat beam splitter, a camera with a bi-telecentric lens, and a translating stage. The LCD screen is used to display sinusoidal fringe patterns and can be moved by the stage to two different positions along the normal direction of a reference plane. The camera captures the deformed fringe patterns reflected by the measured specular surface...
January 22, 2018: Optics Express
Sabrina Chebli, Muriel Rabilloud, Carole Burillon, Viridiana Kocaba
PURPOSE: To evaluate the long-term endothelial tolerance of iris-fixated phakic intraocular lenses (pIOLs) over a 10-year period, to identify predictive factors for endothelial decompensation, and to develop a model to predict endothelial cell survival after pIOL implantation. METHODS: This retrospective study included 130 eyes in 60 patients who underwent pIOL implantation for correction of high myopia from January 2003 to October 2012 at Edouard Herriot Hospital in Lyon, France...
February 2, 2018: Cornea
Thomas A Blake, Timothy J Johnson, Russell G Tonkyn, Brenda M Forland, Tanya L Myers, Carolyn S Brauer, Yin-Fong Su, Bruce E Bernacki, Leonard Hanssen, Gerardo Gonzalez
We have developed methods to measure the directional-hemispherical (ρ) and diffuse (ρd) reflectances of powders, liquids, and disks of powders and solid materials using a commercially available, matte gold-coated integrating sphere and Fourier transform infrared spectrometer. To determine how well the sphere and protocols produce quantitative reflectance data, measurements were made of three diffuse and two specular standards prepared by the National Institute of Standards and Technology (NIST), LabSphere Infragold and Spectralon standards, hand-loaded sulfur and talc powder samples, and water...
January 20, 2018: Applied Optics
Sergi Segarra, Marta Leiva, Daniel Costa, Natàlia Coyo, Maria Sabés-Alsina, José Ríos, Teresa Peña
BACKGROUND: Rabbits are currently not a good model for studying diseases of the corneal endothelium because their corneal endothelial cells (CECs) maintain a high proliferative capacity throughout almost all their life. Addressing this particular feature might allow the use of this species for such a purpose. The aim of this study was to evaluate the corneal endothelial injury after intracameral benzalkonium chloride (BAC) injection into rabbit eyes ex vivo, and to establish the most suitable starting dose for an in vivo study aimed at developing an animal model of corneal endothelial disease...
February 2, 2018: BMC Veterinary Research
Bo Zhuang, Robert Rohling, Purang Abolmaesumi
In recent years, ultrasound has been increasingly used to guide needle insertion procedures for spinal anesthesia. The primary anatomical targets are facet joints and epidural spaces. For these procedures, accurate visualization of the spine anatomy is of critical importance. Challenges arising from the interactions between the ultrasound beam and spinal structures including tilt caused by specular reflections, off-axis interference, and reverberations often result in weakened and blurred vertebra surfaces...
February 2018: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Vyacheslav Alexeyevich Timofeev, A I Nikiforov, Artur Raisovich Tuktamyshev, Vladimir Ivanovich Mashanov, Ivan Dmitrievich Loshkarev, Aleksei A Bloshkin, Anton K Gutakovskii
The GeSiSn, SiSn layer growth mechanisms on Si(100) were investigated and the kinetic diagrams of the morphological GeSiSn, SiSn film states in the temperature range of 150 - 450 °C at the tin content from 0 to 35 % were built. The phase diagram of the superstructural change on the surface of Sn grown on Si(100) in the annealing temperature range of 0 - 850 °C was established. The specular beam oscillations were first obtained during the SiSn film growth from 150 to 300 °C at the Sn content up to 35 %. The transmission electron microscopy and X-ray diffractometry data confirm the crystal perfection and the pseudomorphic GeSiSn, SiSn film state, and also the presence of smooth heterointerfaces between GeSiSn or SiSn and Si...
February 1, 2018: Nanotechnology
Jonathan H Lass, Beth Ann Benetz, Harry J Menegay, Constantinos P Tsipis, Jane Caty Cook, David S Boyer, Michael Singer, Kristine Erickson, Namrata Saroj, Robert Vitti, Karen W Chu, Hadi Moini, Yuhwen Soo, Yenchieh Cheng
PURPOSE: The effects of repeated intravitreal aflibercept injection (IAI) on the corneal endothelium were studied in patients with unilateral neovascular age-related macular degeneration. METHODS: RE-VIEW was a phase 4, open-label, single-arm, multicenter study. Patients received IAI every 8 weeks after 3 monthly doses. Slit-lamp biomicroscopy was performed at all study visits. The central corneal endothelial health was evaluated by specular microscopy in the treated versus untreated fellow eyes at baseline and weeks 24 and 52...
January 30, 2018: Cornea
Fabian P Schmidt, Armin Kolb, Bernd J Pichler
This study depicts the evaluation of a SiPM detector with depth of interaction (DOI) capability via a dual-sided readout that is suitable for high-resolution positron emission tomography and magnetic resonance (PET/MR) imaging. Two different 12×12 pixelated LSO scintillator arrays with a crystal pitch of 1.60 mm are examined. One array is 20 mm-long with a crystal separation by the specular reflector Vikuiti Enhanced Specular Reflector (ESR), and the other one is 18 mm-long and separated by the diffuse reflector Lumirror E60 (E60)...
January 31, 2018: Physics in Medicine and Biology
Neha Kapur, Sridevi Gunda, Surender Dixit, Lokesh Chauhan, Manisha Acharya, Umang Mathur
PURPOSE: The purpose of this study is to evaluate the effect of transfer of donor corneal tissue from McCarey-Kaufmann (MK) medium to Optisol-GS on corneal endothelium. METHODS: This was a prospective, randomized comparative study. Twenty paired human donor corneal tissues of optical quality were retrieved. One tissue of the pair was preserved in Optisol-GS preservative medium (Group A) and other tissue of the pair in MK medium (Group B) at the time of corneoscleral disc excision...
February 2018: Indian Journal of Ophthalmology
Raul Martin
Current corneal assessment technologies make the process of corneal evaluation extremely fast and simple, and several devices and technologies show signs that help in identification of different diseases thereby, helping in diagnosis, management, and follow-up of patients. The purpose of this review is to present and update readers on the evaluation of cornea and ocular surface. This first part reviews a description of slit lamp biomicroscopy (SLB), endothelial specular microscopy, confocal microscopy, and ultrasound biomicroscopy examination techniques and the second part describes the corneal topography and tomography, providing up-to-date information on the clinical recommendations of these techniques in eye care practice...
February 2018: Indian Journal of Ophthalmology
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