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Sergey V Sukhomlinov, Martin H Müser
The mean bond length d between a central atom and its nearest neighbors can be estimated from the position of the first peak in the radial distribution function g(r). However, as we demonstrate here, this estimate does not allow one to deduce temperature-induced changes in d. Instead, skewness has to be included into the analysis, which can be achieved, for example, via the skew normal distribution (SND). Fits to the first peak using the SND give bond length in good agreement with direct measurements of nearest-neighbor distribution functions in crystals as well as with a Voronoi-tessellation based detection of nearest-neighbors in liquids...
January 14, 2017: Journal of Chemical Physics
P A Ndoye Roth, S A Toure, H Kane, A S Sow, A M Wane, J M Ndiaye, A M Ka, J P Diagne, H M Diallo, M E Demedeiros Quenum, M Nguer, E A Ba, P A Ndiaye, M R Ndiaye
PURPOSE: To report the clinical investigation of isolated microspherophakia involving a Senegalese family in order to appreciate its functional impact. OBSERVATIONS: This is a rural family comprised of 7 members. The sibship included three girls and two boys. One of the girls, who lived in a distant zone, was unable to be examined. Of all the examined members of the family, only the father was unaffected by the illness. There was no consanguinity. The general medical examination was normal...
January 10, 2017: Journal Français D'ophtalmologie
Gunnar R Stratton, Fei Dai, Christopher L Bellona, Thomas M Holsen, Eric Reyvell Velazquez Dickenson, Selma Mededovic Thagard
A process based on electrical discharge plasma was tested for the transformation of perfluorooctanoic acid (PFOA). The plasma-based process was adapted for two cases, high removal rate and high removal efficiency. During a 30 minute treatment, the PFOA concentration in 1.4 L aqueous solutions was reduced by 90% with the high rate process (76.5 W input power) and 25% with the high efficiency process (4.1 W input power). Both achieved remarkably high PFOA removal and defluorination efficiencies compared to leading alternative technologies...
January 12, 2017: Environmental Science & Technology
Corina H Pollok, Tim Riesebeck, Christian Merten
Characterizing the stereochemistry of transient photoisomerization products remains a big challenge for the design of molecular machines, such as unidirectional molecular motors. Often these states are not stable long enough to be characterized in detail using conventional spectroscopic tools. The structurally simple camphorquinone imine 1 serves to illustrate the advantage of combining the matrix-isolation technique with vibrational circular dichroism (VCD) spectroscopy for the investigation of photoisomerizations of chiral molecules...
January 12, 2017: Angewandte Chemie
Takuya Iwasaki, Manoharan Muruganathan, Marek E Schmidt, Hiroshi Mizuta
The transformation of systematic vacuum and hydrogen annealing effects in graphene devices on the SiO2 surface is reported based on experimental and van der Waals interaction corrected density functional theory (DFT) simulation results. Vacuum annealing removes p-type dopants and reduces charged impurity scattering in graphene. Moreover, it induces n-type doping into graphene, leading to the improvement of the electron mobility and conductivity in the electron transport regime, which are reversed by exposing to atmospheric environment...
January 11, 2017: Nanoscale
Yan Busby, Emil J W List-Kratochvil, Jean-Jacques Pireaux
Despite of the wide use of blends combining an organic p-type polymer and molecular fullerene-based electron acceptor, the proper characterization of such bulk heterojunction materials is still challenging. In order to highlight structure-to-function relations and improve the device performance, advanced tools and strategies need to be developed to characterize composition and interfaces with a sufficient accuracy. In this work, high-resolution X-ray photoelectron spectroscopy (XPS) is combined with very low energy argon ion beam sputtering to perform a non-destructive depth profile chemical analysis on full Al/P3HT:PCBM/PEDOT:PSS/ITO bulk-heterojunction solar cell device stacks...
January 10, 2017: ACS Applied Materials & Interfaces
Sudi Jawahery, Cory M Simon, Efrem Braun, Matthew Witman, Davide Tiana, Bess Vlaisavljevich, Berend Smit
IRMOF-74 analogues are among the most widely studied metal-organic frameworks (MOFs) for adsorption applications because of their one-dimensional channels and high metal density. Most studies involving the IRMOF-74 series assume that the crystal lattice is rigid. This assumption guides the interpretation of experimental data, as changes in the crystal symmetry have so far been ignored as a possibility in the literature. Here, we report a deformation pattern, induced by the adsorption of argon, for IRMOF-74-V...
January 9, 2017: Nature Communications
Kevin V Murphy, Whitney James Morgan, Zhi Sun, Henry F Schaefer, Jay Agarwal
The ephemeral Criegee intermediate, first postulated over 70 years ago, has only recently been isolated in the gas phase. The sulfur analog of this canonical zwitterion, thioformaldehyde S-sulfide, has eluded similar analysis; however, argon matrix isolation has been achieved (Angew. Chem. 2001, 40, 393-396). Here, thioformaldehyde S-sulfide and its valence valence isomer dithiirane are examined with high-level coupled-cluster methods, including the minimum energy pathway for interconversion. Relative enthalpies, calculated from extrapolated energies at the complete basis set limit of the full CCSDTQ method, are reported...
January 6, 2017: Journal of Physical Chemistry. A
F Horst, G Fehrenbacher, K Zink
PURPOSE: In high energy photon therapy, several radiation protection issues result from photonuclear reactions. The activation of air - directly by photonuclear reactions as well as indirectly by capture of photoneutrons generated inside the linac head - is a major point of concern for the medical staff. The purpose of this study was to estimate the annual effective dose to medical workers due to activated air around a medical high energy electron linac by means of Monte Carlo simulations...
June 2016: Medical Physics
M C Guixeres Esteve, A O Pardo Saiz
CLINICAL CASE: A 14 year-old boy with Coats' disease in his right eye, presented with a visual acuity (VA) of 0.1, micro-aneurysms, exudates, a macular oedema of 959 microns, and peripheral telangiectasias. After 12 months follow-up with 6 ranibizumab injections and 3 sessions of argon laser photocoagulation, the macular oedema remained and VA was 0.2. Following 4 aflibercept injections and another 2 laser sessions, he had a good foveal slope and a VA of 0.5, with no recurrences in the last 12 months...
December 27, 2016: Archivos de la Sociedad Española de Oftalmología
Malvika Arya, Emily D Cole, Eduardo A Novais, Ricardo N Louzada, Nadia K Waheed, Jay S Duker
PURPOSE: To illustrate errors in the automated segmentation image analysis of optical coherence tomography angiography after laser photocoagulation therapy for Type 2 neovascularization. METHODS: This case report describes a patient with extrafoveal Type 2 neovascularization treated with argon laser photocoagulation evaluated before and after treatment by optical coherence tomography angiography. RESULTS: Disrupted retinal layers after laser photocoagulation therapy lead to segmentation errors...
December 28, 2016: Retinal Cases & Brief Reports
Emily Mace, Craig Aalseth, Jill Brandenberger, Anthony Day, Eric Hoppe, Paul Humble, Martin Keillor, Justin Kulongoski, Cory Overman, Mark Panisko, Allen Seifert, Signe White, Eric Wilcox Freeburg, Richard Williams
Argon-39 can be used as a tracer for age-dating glaciers, oceans, and more recently, groundwater. With a half-life of 269 years, (39)Ar fills an intermediate age range gap (50-1,000 years) not currently covered by other common groundwater tracers. Therefore, adding this tracer to the data suite for groundwater studies provides an important tool for improving our understanding of groundwater systems. We present the methods employed for arriving at an age-date for a given sample of argon degassed from groundwater...
December 21, 2016: Applied Radiation and Isotopes
Giorgos Papaspyrou, Maximilian Linxweiler, Dirk Knöbber, Bernhard Schick, Basel Al Kadah
INTRODUCTION: Tonsillotomy is increasingly gaining acceptance as the treatment for tonsillar hyperplasia resulting in obstructive symptoms. The aim of this study was to compare the long-term results of CO2 laser tonsillotomy with those of argon plasma coagulation (APC) tonsillotomy. METHODS: The data of 64 children, aged 2-10 years (mean 4.7 years), treated in the Department of Otolaryngology, Head and Neck Surgery, in Homburg, Germany with APC (36 patients) or CO2 laser (28 patients) for tonsillar hyperplasia between June 2004 and December 2004 were available for analysis...
January 2017: International Journal of Pediatric Otorhinolaryngology
D C McDonald, D T Mauney, D Leicht, J H Marks, J A Tan, J-L Kuo, M A Duncan
Ion-molecule complexes of the form H(+)Arn are produced in pulsed-discharge supersonic expansions containing hydrogen and argon. These ions are analyzed and mass-selected in a reflectron spectrometer and studied with infrared laser photodissociation spectroscopy. Infrared spectra for the n = 3-7 complexes are characterized by a series of strong bands in the 900-2200 cm(-1) region. Computational studies at the MP2/aug-cc-pVTZ level examine the structures, binding energies, and infrared spectra for these systems...
December 21, 2016: Journal of Chemical Physics
Marija M Bozic, Jelena B Karadzic, Igor M Kovacevic, Ivan S Marjanovic
PURPOSE: To assess the effect of panretinal laser photocoagulation on ocular pulse amplitude (OPA) in normotensive eyes with proliferative diabetic retinopathy. METHODS: Prospectively, we performed unilateral argon laser panretinal photocoagulation (PRP) in 30 patients with diabetes mellitus type II and previously untreated bilateral proliferative diabetic retinopathy. Before and 7 and 30 days after the treatment, OPA was measured using dynamic contour tonometer...
November 28, 2016: European Journal of Ophthalmology
A A Rusanov, N V Kazakov, A V Gerasin, M G Kovalev, A L Akopov
AIM: To develop the new method of laser recanalization of airways for tumoral stenosis. MATERIAL AND METHODS: It is proposed to conduct laser effect in the gas environment that does not support combustion (argon). Also the device for these AIM: is suggested. The method is called argon-laser ablation (ALA). A comparison of ALA and conventional high-energy laser exposure (LPD) was performed. RESULTS: ALA and LPD were used in 46 patients and 17 patients with non-small cell lung cancer...
2016: Khirurgiia
Tatsumasa Hiratsuka, Hideki Tanaka, Minoru T Miyahara
We find the rule of capillary condensation from the metastable state in nanoscale pores based on the transition state theory. The conventional thermodynamic theories cannot achieve it because the metastable capillary condensation inherently includes an activated process. We thus compute argon adsorption isotherms on cylindrical pore models and atomistic silica pore models mimicking the MCM-41 materials by the grand canonical Monte Carlo and the gauge cell Monte Carlo methods and evaluate the rate constant for the capillary condensation by the transition state theory...
December 27, 2016: ACS Nano
Y Almadori, Ł Borowik, N Chevalier, J-C Barbé
Thermally induced solid-state dewetting of ultra-thin films on insulators is a process of prime interest, since it is capable of easily forming nanocrystals. If no particular treatment is performed to the film prior to the solid-state dewetting, it is already known that the size, the shape and the density of nanocrystals is governed by the initial film thickness. In this paper, we report a novel approach to control the size and the surface density of silicon nanocrystals based on an argon-implantation preliminary surface treatment...
January 27, 2017: Nanotechnology
Youngwook Park, Hani Kang, Heon Kang
Brute force orientation by an electric field is a promising way of controlling the orientation of polar molecules in the gas phase, but its application to condensed-phase molecules has been very limited. We studied the reorientation of formaldehyde molecules in a solid Ar matrix under the influence of a strong electric field using reflection absorption infrared spectroscopy. Asymptotically perfect alignment of the formaldehyde molecules along the field was achieved at field strengths exceeding 1×10(8)  V m(-1) ...
December 20, 2016: Angewandte Chemie
E W Larsen, S Carlström, E Lorek, C M Heyl, D Paleček, K J Schafer, A L'Huillier, D Zigmantas, J Mauritsson
The sub-cycle dynamics of electrons driven by strong laser fields is central to the emerging field of attosecond science. We demonstrate how the dynamics can be probed through high-order harmonic generation, where different trajectories leading to the same harmonic order are initiated at different times, thereby probing different field strengths. We find large differences between the trajectories with respect to both their sensitivity to driving field ellipticity and resonant enhancement. To accurately describe the ellipticity dependence of the long trajectory harmonics we must include a sub-cycle change of the initial velocity distribution of the electron and its excursion time...
December 19, 2016: Scientific Reports
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