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Davide Farronato, Davide Fumagalli, Farah Asa'ad, Giulio Rasperini
The aim of this study was to evaluate different cleaning procedures for customized laser-microtextured titanium abutments. A total of 20 customized laser-microtextured abutments were randomized into four groups: no cleaning (control group), ultrasonic treatments + autoclave cycle (group 1), ultrasonic treatments + argon plasma (group 2), and only argon plasma (group 3). Surface contaminants were assessed through scanning electron microscopy and energy-dispersive x-ray spectroscopy microanalysis. In the control group, 99...
April 20, 2018: International Journal of Periodontics & Restorative Dentistry
Vasily V Zhakhovsky, Alexei P Kryukov, Vladimir Yu Levashov, Irina N Shishkova, Sergey I Anisimov
Boundary conditions required for numerical solution of the Boltzmann kinetic equation (BKE) for mass/heat transfer between evaporation and condensation surfaces are analyzed by comparison of BKE results with molecular dynamics (MD) simulations. Lennard-Jones potential with parameters corresponding to solid argon is used to simulate evaporation from the hot side, nonequilibrium vapor flow with a Knudsen number of about 0.02, and condensation on the cold side of the condensed phase. The equilibrium density of vapor obtained in MD simulation of phase coexistence is used in BKE calculations for consistency of BKE results with MD data...
April 16, 2018: Proceedings of the National Academy of Sciences of the United States of America
Paul Andrew Christensen, Zeinab T A W Mashhadani, Abd Halim Bin Md Ali, Michael A Carroll, Philip A Martin
This paper reports in-situ Fourier Transform Infra Red (FTIR) spectroscopic studies on the non-thermal plasma reaction of isopropyl alcohol in dinitrogen at Macor (a ceramic containing oxides of Al, Mg and Si) and the analogous thermally-driven process. Whilst isopropyl alcohol did not react at the Macor at temperatures up to 600°C, the study of the non-thermal plasma-driven process at the ceramic led to unexpected chemistry hitherto not observed, primarily the reaction of IPA in dinitrogen at short timescales to produce methane, HCN, acetone and "cold" CO at ca...
April 17, 2018: Journal of Physical Chemistry. A
Onur Tosun, Mohammed Salehi-Fashami, Balamurugan Balasubramanian, Ralph Skomski, David J Sellmyer, George C Hadjipanayis
In this work, we investigated the magnetic and structural properties of isolated Mn₅Ge₃ nanoparticles prepared by the cluster-beam deposition technique. Particles with sizes between 7.2 and 12.6 nm were produced by varying the argon pressure and power in the cluster gun. X-ray diffraction (XRD)and selected area diffraction (SAD) measurements show that the nanoparticles crystallize in the hexagonal Mn₅Si₃-type crystal structure, which is also the structure of bulk Mn₅Ge₃. The temperature dependence of the magnetization shows that the as-made particles are ferromagnetic at room temperature and have slightly different Curie temperatures...
April 15, 2018: Nanomaterials
Hong Qi, Lourdes Soto-Gonzalez, Konstantin A Krychtiuk, Sarah Ruhittel, Christoph Kaun, Walter S Speidl, Attila Kiss, Bruno K Podesser, Shanglong Yao, Klaus Markstaller, Klaus U Klein, Verena Tretter
BACKGROUND: The noble gas argon induces cardioprotection in a rabbit model of myocardial ischemia and reperfusion. However, no studies in human primary cells or subjects have been performed so far. We used human cardiac myocyte-like progenitor cells (HCMs) to investigate the protective effect on the cellular level. METHODS: HCMs were pretreated with 30% or 50% argon before oxygen-glucose deprivation (OGD) and reperfusion. We evaluated apoptotic states by flow cytometry and the activation of mitogen-activated protein kinase (MAPKs) members extracellular signal-regulated kinase (ERK), c-jun N-terminal kinase (JNK), p38 MAPkinase, and protein kinase B (Akt) by Westernblot analysis and by activity assays of downstream transcription factors...
May 2018: Shock
Lester Andrews, Han-Gook Cho, Zongtang Fang, Monica Vasiliu, David A Dixon
Laser ablation of tungsten metal provides W atoms which react with phosphine and arsine during condensation in excess argon and neon, leading to major new infrared (IR) absorptions. Annealing, UV irradiation, and deuterium substitution experiments coupled with electronic structure calculations at the density functional theory level led to the assignment of the observed IR absorptions to the E≡WH3 and HE═WH2 molecules for E = P and As. The potential energy surfaces for hydrogen transfer from PH3 to the W were calculated at the coupled-cluster CCSD(T)/complete basis set level...
April 16, 2018: Inorganic Chemistry
Chun-Hao Li, Ji-Hong Zhao, Qi-Dai Chen, Jing Feng, Hong-Bo Sun
Non-doped black silicon (b-Si) is fabricated on the surface layer of a near-intrinsic Si substrate by nanosecond (ns) laser direct writing in an argon (Ar) atmosphere. The non-doped samples exhibit a near-unity sub-bandgap (1100∼2500  nm) absorptance of more than 50%. Amazingly, the resistivity of the ns laser irradiated b-Si layer is about five orders of magnitude lower than that of the unprocessed Si substrate. The carrier density of the b-Si layer is about 1×1018   cm-3 , according to the Hall effect measurement...
April 15, 2018: Optics Letters
Andreas Katsanos, Anastasios G Konstas, Dimitrios G Mikropoulos, Luciano Quaranta, Irini C Voudouragkaki, Georgios P Athanasopoulos, Ioannis Asproudis, Miguel A Teus
In the last decade, selective laser trabeculoplasty (SLT) has been commonly used in the management of several different types of glaucoma, as either primary or adjunct therapy. The technique has an excellent safety profile and is at least as effective as argon laser trabeculoplasty. Although the actual mechanism of action of SLT remains unclear, evidence has shown that it does not induce morphologically evident trabecular meshwork alterations. SLT's non-disruptive mode of action offers the advantage of repeatability...
April 11, 2018: Advances in Therapy
Ilya S Sosulin, Ekaterina S Shiryaeva, Daniil A Tyurin, Vladimir I Feldman
Intermolecular complexes between CHF3 and CO have been studied by ab initio calculations and IR matrix isolation spectroscopy. The computations at the MP2 and CCSD(T) levels of theory indicated five minima on the potential energy surface (PES). The most energetically favorable structure is the C(CO)-H(CHF3) coordinated complex (Cs symmetry) with the stabilization energy of 0.84 kcal/mol as computed at the CCSD(T) level (with ZPVE and BSSE corrections). This is the only structure experimentally found in argon and krypton matrixes, whereas the weaker non-hydrogen-bonded complexes predicted by theory were not detected...
April 7, 2018: Journal of Physical Chemistry. A
Rena C Moon, Andre F Teixeira, Manoel Galvao Neto, Natan Zundel, Bruno Queiroz Sander, Flavio Mitidieri Ramos, Felipe Matz, Giorgio A Baretta, Luiz Gustavo de Quadros, Eduardo Grecco, Thiago Souza, Sergio A Barrichello, Admar Concon Filho, Eduardo Nobuyuki Usuy, Artagnan Menezes Barbosa de Amorim, Muhammad A Jawad
BACKGROUND: Endoscopic approaches exist for targeting weight regain after Roux-en-Y gastric bypass (RYGB), including endoscopic suturing, clipping, and sclerotherapy. Argon plasma coagulation (APC) is a noncontact electrocoagulation method, and when used in RYGB patients, it has shown reduction in the diameter of the gastrojejunal anastomosis. OBJECTIVES: To study the effectiveness of APC for weight regain in terms of weight loss for RYGB patients, from eight bariatric centers...
April 8, 2018: Obesity Surgery
Linda Lehmke, Mark Coburn, Manfred Möller, Rosmarie Blaumeiser-Debarry, Pia Lenzig, Dominik Wiemuth, Stefan Gründer
Acid-sensing ion channels (ASICs) are neuronal Na+ channels that are activated by extracellular acidification. Inhibiting ASICs is neuroprotective in mouse models of ischemic stroke. As inhalational anesthetics interact with many ion channels and as some of them have neuroprotective effects, we hypothesized that inhalational anesthetics modulate ASICs. We expressed different homo- and heteromeric ASICs heterologously in Xenopus oocytes. We co-applied with acidic pH the halogenated inhalational anesthetics sevoflurane, desflurane, and isoflurane and the noble gases xenon and argon at concentrations that are roughly equivalent to their minimal alveolar concentrations and analyzed their effect on current kinetics and amplitude...
April 5, 2018: Neuropharmacology
Cameron D Wright
Modern thoracic surgery requires knowledge and skill in advanced bronchoscopic techniques. Rigid bronchoscopy remains a workhorse for the management of central airway obstruction. Dilation of tracheal strictures is now much simpler with the advent of the balloon dilator, which can be passed through a therapeutic bronchoscope. Numerous adjuncts, such as laser, argon beam coagulation, electrocautery, and cryotherapy, can be used to improve airway patency. There are now numerous stenting options for strictures that require stenting to maintain airway patency...
May 2018: Thoracic Surgery Clinics
Timothy R Elliott, Zacharias P Tsiamoulos, Siwan Thomas-Gibson, Noriko Suzuki, Leonidas A Bourikas, Ailsa Hart, Paul Bassett, Brian P Saunders
BACKGROUND:  Delayed bleeding is the most common significant complication after piecemeal endoscopic mucosal resection (p-EMR) of large nonpedunculated colorectal polyps (NPCPs). Risk factors for delayed bleeding are incompletely defined. We aimed to determine risk factors for delayed bleeding following p-EMR. METHODS:  Data were analyzed from a prospective tertiary center audit of patients with NPCPs ≥ 20 mm who underwent p-EMR between 2010 and 2012...
April 6, 2018: Endoscopy
Olusola Olawoye, Adelina A Ashaye, Tarela F Sarimiye
Aim: To report the safety and efficacy of Argon Laser Trabeculoplasty (ALT) in reducing intraocular pressure (IOP). Settings and Design: This was a retrospective study performed on 25 eyes of 25 patients. Methods and Materials: Consecutive patients who met the inclusion criteria for ALT were recruited from the ophthalmic clinic of the University College Hospital Ibadan, Nigeria and followed up for a minimum period of six months. Two criteria were used to define successful response...
December 2017: Ghana Medical Journal
Michael Barter, Jon Hartley, François-Joseph Yazigi, Ross J Marshall, Ross S Forgan, Adrian Porch, Martin Owen Jones
Ammonia absorption has been investigated in metal-organic frameworks (UiO-67, HKUST-1 and CPO-27-Co) using custom-built apparatus that allows simultaneous neutron powder diffraction (NPD), microwave dielectric characterisation and out-gas mass spectroscopy of solid-state materials during ammonia adsorption. Deuterated ammonia was flowed through the sample and absorption monitored using mass flow meters and mass spectroscopy. Argon gas was then flowed through the ammoniated sample to cause ammonia desorption...
April 4, 2018: Physical Chemistry Chemical Physics: PCCP
Ce Han, Qun Li, Dewen Wang, Qingqing Lu, Zhicai Xing, Xiurong Yang
Exploration of economical electrocatalysts for highly efficient and stable oxygen reduction reaction (ORR) is believed to be essential for diverse future renewable energy applications. Herein, cobalt sulfide nanowire core encapsulated in a N, S codoped graphitic carbon shell (CoS NWs@NSC) is successfully fabricated via the calcination of polydopamine-coated Co(CO3 )0.5 (OH)0.11 H2 O NWs with sulfur powder under argon atmosphere. The uniform encapsulation of CoS core by N, S codoped graphitic carbon shell favors the interaction of the core-shell structure for generating stable and numerous ORR active sites homogeneously dispersed throughout the materials...
April 3, 2018: Small
D T Halfen, L M Ziurys
The pure rotational spectrum of the AlC2 radical (X[combining tilde]2A1) has been measured using Fourier transform microwave/millimeter-wave (FTMmmW) techniques in the frequency range 21-65 GHz. This study is the first high-resolution spectroscopic investigation of this molecule. AlC2 was created in a supersonic jet from the reaction of aluminum, generated by laser ablation, with a mixture of CH4 or HCCH, diluted in argon, in the presence of a DC discharge. Three transitions (NKa,Kc = 101 → 000, 202 → 101, and 303 → 202) were measured, each consisting of multiple fine/hyperfine components, resulting from the unpaired electron in the species and the aluminum-27 nuclear spin (I = 5/2)...
April 3, 2018: Physical Chemistry Chemical Physics: PCCP
Stefan Mueller, Simon Draeger, Xiaonan Ma, Matthias Hensen, Tristan Kenneweg, Walter Pfeiffer, Tobias Brixner
We demonstrate two-quantum (2Q) coherent two-dimensional (2D) electronic spectroscopy using a shot-to-shot-modulated pulse shaper and fluorescence detection. Broadband collinear excitation is realized with the supercontinuum output of an argon-filled hollow-core fiber enabling us to excite multiple transitions simultaneously in the visible range. The 2Q contribution is extracted via a three-pulse sequence with 16-fold phase cycling and simulated employing cresyl violet as a model system. Furthermore, we report the first experimental realization of one-quantum-two-quantum (1Q-2Q) 2D spectroscopy, offering less congested spectra as compared to the 2Q implementation...
April 2, 2018: Journal of Physical Chemistry Letters
M Afsharmanesh, M Habibi
In the present context, the extraction system of a helicon ion source has been simulated and constructed. Results of the ion source commissioning at up to 20 kV are presented as well as simulations of an ion beam extraction system. Argon current of more than 200 μA at up to 20 kV is extracted and is characterized with a Faraday cup and beam profile monitoring grid. By changing different ion source parameters such as RF power, extraction voltage, and working pressure, an ion beam with current distribution exhibiting a central core has been detected...
March 2018: Review of Scientific Instruments
Yaguo Tang, Xu Shan, Zhaohui Liu, Shanshan Niu, Enliang Wang, Xiangjun Chen
The low count rate of (e, 2e) electron momentum spectroscopy (EMS) has long been a major limitation of its application to the investigation of molecular dynamics. Here we report a new EMS apparatus developed for time-resolved experiments in the nanosecond time scale, in which a double toroidal energy analyzer is utilized to improve the sensitivity of the spectrometer and a nanosecond pulsed electron gun with a repetition rate of 10 kHz is used to obtain an average beam current up to nA. Meanwhile, a picosecond ultraviolet laser with a repetition rate of 5 kHz is introduced to pump the sample target...
March 2018: Review of Scientific Instruments
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