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https://www.readbyqxmd.com/read/28525866/theoretical-spectroscopic-insights-of-tautomers-and-enantiomers-of-penicillamine
#1
J Mendes, K J de Almeida, J L Neto, T C Ramalho, H A Duarte
B3LYP and MP2 calculations have been carried out to investigate tautomers and enantiomers of penicillamine (Pen). Their infrared (IR), ultraviolet (UV), circular dichroism (CD) and nuclear magnetic resonance (NMR) spectra were obtained at linear-response, time-dependent DFT (TD-DFT). IR, UV and NMR spectra cannot be used to identify Pen enantiomers, showing nearly equal spectral profiles. CD spectra, however, give rise to completely symmetric signals, forming a perfect specular image to each other. Distinct CD profiles were also obtained for Pen tautomers...
May 11, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28505746/alternative-extrapolation-based-symmetry-boundary-implementations-for-the-axisymmetric-lattice-boltzmann-method
#2
Liangqi Zhang, Shiliang Yang, Zhong Zeng, Jie Chen, Lingquan Wang, Jia Wei Chew
In this study, alternative symmetry boundary implementations for the axisymmetric lattice Boltzmann (LB) method are proposed based on the nonequilibrium extrapolation and the direct extrapolation schemes. The proposed boundary schemes are directly implemented on the symmetry axis, and the postcollision distribution function and the macroscopic variables at the boundary nodes are extrapolated from the inner fluid nodes; thereby, the singularities arising at the symmetry axis (r=0) during the collision and the macroscopic variable calculations are completely avoided...
April 2017: Physical Review. E
https://www.readbyqxmd.com/read/28500960/infrared-reflectometry-of-skin-analysis-of-backscattered-light-from-different-skin-layers
#3
Miguel A Pleitez, Otto Hertzberg, Alexander Bauer, Tobias Lieblein, Mathias Glasmacher, Hans Tholl, Werner Mäntele
We have recently reported infrared spectroscopy of human skin in vivo using quantum cascade laser excitation and photoacoustic or photothermal detection for non-invasive glucose measurement . Here, we analyze the IR light diffusely reflected from skin layers for spectral contributions of glucose. Excitation of human skin by an external cavity tunable quantum cascade laser in the spectral region from 1000 to 1245cm(-1), where glucose exhibits a fingerprint absorption, yields reflectance spectra with some contributions from glucose molecules...
May 1, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28494229/an-algorithm-for-quantitatively-modeling-reflected-ultrasonic-bounded-pulses-and-beams
#4
Reza Malehmir, Nasser Kazemi, Douglas R Schmitt
The study of the reflected acoustic waves plays an important role in our understanding of media. We provide an algorithm to propagate the ultrasonic bounded beam source and study its reflection from any horizontal and homogenous water-solid boundary. This algorithm implements a hybrid combination of the phase-advance wavefield continuation in the frequency domain and the complex analytic solution for the acoustic reflectivity. The peak amplitude of the specularly reflected beam is in agreement with the laboratory measured acoustic reflection from water-Aluminum and water-Copper alloy boundaries...
April 29, 2017: Ultrasonics
https://www.readbyqxmd.com/read/28488075/effects-of-phacoemulsification-with-versus-without-viscoelastic-devices-on-surgical-outcomes
#5
İbrahim Taşkın, Lokman Aslan
PURPOSE: The aim of this study is to report surgical outcomes in patients undergoing phacoemulsification surgery (PE) with versus without ophthalmic viscosurgical devices (OVDs). METHODS: This is a comparative case series study. In total, 145 patients who performed PE with OVDs in 68 eyes (Group 1) and without OVD in 77 eyes (Group 2) were enrolled. A comprehensive ophthalmological examination was performed including slit-lamp, fundus examination. Best-corrected visual acuity (BCVA), intraocular pressure (IOP) specular endothelial microscopy (SM), and ultrasound pachymetry (UP) were also measured before surgery and at four-time points postoperatively...
May 9, 2017: International Ophthalmology
https://www.readbyqxmd.com/read/28486855/the-effects-of-smoking-on-corneal-endothelial-cells-a-cross-sectional-study-on-a-population-from-isfahan-iran
#6
Khodayar Golabchi, Mohammad Ali Abtahi, Ali Salehi, Hamidreza Jahanbani-Ardakani, Sara Ghafari, Ziba Farajzadegan
PURPOSE: The aim of this study is to compare the effect of smoking in corneal endothelial cell number and morphology by specular microscopy on a non-smoker population. METHODS: Our cross-sectional study was performed on 150 participants from a non-smoker population. Non-contact specular microscopy (Tomey Corporation Inc., Nagoya, Japan) was performed in the center of the cornea of all subjects. The cell density (CD), average cell size (AVG), percent of hexagonality (HEX %), and central corneal thickness (CCT) were calculated and compared in both groups...
May 10, 2017: Cutaneous and Ocular Toxicology
https://www.readbyqxmd.com/read/28480616/transferable-organic-semiconductor-nanosheets-for-application-in-electronic-devices
#7
Simon J Noever, Michael Eder, Fabio Del Giudice, Jan Martin, Franz X Werkmeister, Stefan Hallwig, Stefan Fischer, Oliver Seeck, Nils-Eike Weber, Clemens Liewald, Fritz Keilmann, Andrey Turchanin, Bert Nickel
A method has been developed to stabilize and transfer nanofilms of functional organic semiconductors. The method is based on crosslinking of their topmost layers by low energy electron irradiation. The films can then be detached from their original substrates and subsequently deposited onto new solid or holey substrates retaining their structural integrity. Grazing incidence X-ray diffraction, X-ray specular reflectivity, and UV-Vis spectroscopy measurements reveal that the electron irradiation of ≈50 nm thick pentacene films results in crosslinking of their only topmost ≈5 nm (3-4 monolayers), whereas the deeper pentacene layers preserve their pristine crystallinity...
May 8, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28480600/ophthalmic-parameters-in-adult-lowland-paca-cuniculus-paca-raised-in-captivity
#8
Camila P Balthazar da Silveira, Tiago B Lima, Roberta M Crivelaro, Luciana C C de Lacerda, Ivan R M Pádua, Roberta Renzo, Alexandre A F de Barros Sobrinho, Fabrício S Oliveira, Marcela Aldrovani, José L Laus
OBJECTIVE: To investigate the ophthalmic parameters of lowland pacas, including the anatomic features, tear production, intraocular pressure, central corneal thickness, and morphology of the corneal endothelium. ANIMALS STUDIED: Thirteen adult, anesthetized Cuniculus paca. PROCEDURE: Eyes were evaluated using slit-lamp biomicroscopy, the Schirmer tear test I, digital applanation tonometry, binocular indirect ophthalmoscopy, and noncontact specular microscopy...
May 8, 2017: Veterinary Ophthalmology
https://www.readbyqxmd.com/read/28465835/a-rabbit-model-study-to-determine-the-efficacy-of-a-prototype-corneal-endothelium-protector-during-cataract-surgery
#9
Annabel C Y Chew, Anita Chan, Monisha E Nongpiur, Gary Peh, Veluchamy A Barathi, Nyein C Lwin, Charles Ong, Shamira Perera
Purpose. We evaluated the efficacy and safety of a mechanical device, the P-chute, in corneal endothelium preservation during phacoemulsification in a rabbit model. Methods. Twenty-four rabbits were randomly assigned into 2 groups. One eye of each rabbit underwent phacoemulsification that simulated the removal of a dense nucleus, with or without the P-chute. Serial slit-lamp examinations, anterior segment optical coherence tomography (ASOCT) scans, and specular microscopy were performed. Three rabbits from each group were sacrificed on postoperative days (PODs) 1, 5, 7, and 14...
2017: Journal of Ophthalmology
https://www.readbyqxmd.com/read/28463297/rendering-of-specular-curved-objects-in-polygon-based-computer-holography
#10
Hirohito Nishi, Kyoji Matsushima
A realistic rendering technique is presented for creating large-scale computer-generated holograms. The technique is based on the polygon-based method, but allows specular curved surfaces to be reconstructed without increasing the number of polygons. In this technique, specular flat surfaces are transformed into curved surfaces. This is achieved by controlling the direction of reflected light, using fragmentary plane waves. An actual large-scale computer-generated hologram is created, and is used to verify the validity and practicality of the technique...
May 1, 2017: Applied Optics
https://www.readbyqxmd.com/read/28434385/digital-curation-and-online-resources-digital-scanning-of-surgical-tools-at-the-royal-college-of-physicians-and-surgeons-of-glasgow-for-an-open-university-learning-resource
#11
Kirsty Earley, Daniel Livingstone, Paul M Rea
Collection preservation is essential for the cultural status of any city. However, presenting a collection publicly risks damage. Recently this drawback has been overcome by digital curation. Described here is a method of digitisation using photogrammetry and virtual reality software. Items were selected from the Royal College of Physicians and Surgeons of Glasgow archives, and implemented into an online learning module for the Open University. Images were processed via Agisoft Photoscan, Autodesk Memento, and Garden Gnome Object 2VR...
January 2017: Journal of Visual Communication in Medicine
https://www.readbyqxmd.com/read/28427301/corneal-endothelial-changes-in-long-term-cannabinoid-users
#12
Nihat Polat, Birgul Cumurcu, Tongabay Cumurcu, İlknur Tuncer
PURPOSE: The aim of this study was to evaluate the effects of long-term cannabis use on the corneal endothelial cells with the specular microscopy. METHODS: The study enrolled 28 eyes of 28 patients diagnosed with cannabinoid use disorder. The cannabinoid group was selected among patients who had been using the substance for 3 days or more per week over the past 1 year. 32 eyes of 32 age- and sex-matched healthy individuals enrolled as control group in the study...
April 20, 2017: Cutaneous and Ocular Toxicology
https://www.readbyqxmd.com/read/28422428/identification-of-transthyretin-fibril-formation-inhibitors-using-structure-based-virtual-screening
#13
Gabriella Ortore, Adriano Martinelli
Transthyretin (TTR) is the primary carrier for thyroxine (T4 ) in cerebrospinal fluid and a secondary carrier in blood. TTR is a stable homotetramer, but certain factors, genetic or environmental, could promote its degradation to form amyloid fibrils. A docking study using crystal structures of wild-type TTR was planned; our aim was to design new ligands that are able to inhibit TTR fibril formation. The computational protocol was thought to overcome the multiple binding modes of the ligands induced by the peculiarity of the TTR binding site and by the pseudosymmetry of the site pockets, which generally weaken such structure-based studies...
April 19, 2017: ChemMedChem
https://www.readbyqxmd.com/read/28415262/thermophoretic-force-on-nanocylinders-in-the-free-molecule-regime
#14
Jun Wang, Shuang Luo, Guodong Xia
We theoretically investigate the thermophoresis of nanocylinders in the free molecule regime, wherein the nonrigid-body effect is taken into account. The analytical formulas of the thermophoretic forces on cylinders suspended in both simple gases and binary gas mixtures are derived for the two limiting collision models, i.e., specular and diffuse scatterings, based on the gas kinetic theory. In the limit of the rigid-body collision, the expressions can be reduced to the theoretical results of Garcia-Ybarra and Rosner [AIChE J...
March 2017: Physical Review. E
https://www.readbyqxmd.com/read/28414357/infrared-brewster-angle-polarizing-beam-splitter-using-a-high-index-prism-with-a-small-wedge-angle
#15
R M A Azzam
Specular reflection at the Brewster angle by a planar surface of a high-refractive-index transparent substrate is an effective means of generating linearly polarized light in the infrared. However, in such a reflection linear polarizer, the refracted light beam is usually dumped. In this paper we describe a polarizing beam splitter (PBS) that uses a high-index prism with a small wedge angle to generate two orthogonally p and s linearly polarized beams that travel in orthogonal directions. A single-layer antireflection coating (ARC) at the exit face of the prism can be embedded with aligned Ag nano needles to suppress the transmission of the small, residual, s-polarized refracted component...
April 10, 2017: Applied Optics
https://www.readbyqxmd.com/read/28398905/an-integrated-model-of-scintillator-reflector-properties-for-advanced-simulations-of-optical-transport
#16
Emilie Roncali, Mariele Stockhoff, Simon R Cherry
Accurately modeling the light transport in scintillation detectors is essential to design new detectors for nuclear medicine or high energy physics. Optical models implemented in software such as Geant4 and GATE suffer from important limitations that we addressed by implementing a new approach in which the crystal reflectance was computed from 3D surface measurements. The reflectance was saved in a look-up-table (LUT) then used in Monte Carlo simulation to determine the fate of optical photons. Our previous work using this approach demonstrated excellent agreement with experimental characterization of crystal light output in a limited configuration, i...
April 11, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28388176/role-of-magnetosonic-solitons-in-perpendicular-collisionless-shock-reformation
#17
Renaud Gueroult, Yukiharu Ohsawa, Nathaniel J Fisch
The nature of the magnetic structure arising from ion specular reflection in shock compression studies is examined by means of 1D particle-in-cell simulations. Propagation speed, field profiles, and supporting currents for this magnetic structure are shown to be consistent with a magnetosonic soliton. Coincidentally, this structure and its evolution are typical of foot structures observed in perpendicular shock reformation. To reconcile these two observations, we propose, for the first time, that shock reformation can be explained as the result of the formation, growth, and subsequent transition to a supercritical shock of a magnetosonic soliton...
March 24, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28383814/specular-and-diffuse-reflectance-of-phase-separated-polymer-blend-films
#18
Asritha Nallapaneni, Matthew D Shawkey, Alamgir Karim
Diffuse reflectors have various applications in devices ranging from liquid crystal displays to light emitting diodes, to coatings. Herein, specular and diffuse reflectance from controlled phase separation of polymer blend films, a well-known self-organization process, are studied. Temperature-induced spinodal phase separation of polymer blend films in which one of the components is selectively extracted is shown to exhibit enhanced surface roughness as compared to unextracted films, leading to a notable increase of diffuse reflectance...
April 6, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/28380864/transient-polarized-radiative-transfer-analysis-in-a-scattering-medium-by-a-discontinuous-finite-element-method
#19
Cun-Hai Wang, Hong-Liang Yi, He-Ping Tan
Transient (time-dependent) polarized radiative transfer in a scattering medium exposed to an external collimated beam illumination is conducted based on the time-dependent polarized radiative transfer theory. The transient term, which persists the nanosecond order time and cannot be ignored for the time-dependent radiative transfer problems induced by a short-pulsed beam, is considered as well as the polarization effect of the radiation. A discontinuous finite element method (DFEM) is developed for the transient vector radiative transfer problem and the derivation of the discrete form of the governing equation is presented...
April 3, 2017: Optics Express
https://www.readbyqxmd.com/read/28380096/visual-rehabilitation-using-mini-scleral-contact-lenses-after-penetrating-keratoplasty
#20
Guilherme Andrade do Nascimento Rocha, Patrícia Oliveira Braga Miziara, Ana Clara Vieira de Castro, Arthur Andrade do Nascimento Rocha
Purpose: To report the visual rehabilitation outcomes and complications of patients fitted with mini-scleral rigid gas-permeable (RGP) contact lenses (mini-SCLs) after penetrating keratoplasty. Methods: We retrospectively reviewed 27 eyes (21 patients) that were fitted with mini-SCLs between October 2013 and December 2014. We analyzed demographic data, previous corneal disorders, visual outcomes, interval from keratoplasty to contact lens fitting, topographic and specular microscope data, fitted contact lens parameters, and complications...
January 2017: Arquivos Brasileiros de Oftalmologia
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