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Linnea Jarenbäck, Göran Eriksson, Stefan Peterson, Jaro Ankerst, Leif Bjermer, Ellen Tufvesson
BACKGROUND: COPD is defined as partly irreversible airflow obstruction. The response pattern of bronchodilators has not been followed in advanced lung function parameters. PURPOSE: The aim of this study was to investigate bronchodilator response pattern in advanced lung function parameters in a continuous fashion along forced expiratory volume in 1 second (FEV1) percent predicted (%p) in COPD patients and controls. PATIENTS AND METHODS: Eighty-one smokers/ex-smokers (41 controls and 40 COPD) performed spirometry, body plethysmography, impulse oscillometry and single-breath helium dilution carbon monoxide diffusion at baseline, after salbutamol inhalation and then after an additional inhalation of ipratropium...
2016: International Journal of Chronic Obstructive Pulmonary Disease
Stefan Zeller, Maksim Kunitski, Jörg Voigtsberger, Anton Kalinin, Alexander Schottelius, Carl Schober, Markus Waitz, Hendrik Sann, Alexander Hartung, Tobias Bauer, Martin Pitzer, Florian Trinter, Christoph Goihl, Christian Janke, Martin Richter, Gregor Kastirke, Miriam Weller, Achim Czasch, Markus Kitzler, Markus Braune, Robert E Grisenti, Wieland Schöllkopf, Lothar Ph H Schmidt, Markus S Schöffler, Joshua B Williams, Till Jahnke, Reinhard Dörner
Quantum tunneling is a ubiquitous phenomenon in nature and crucial for many technological applications. It allows quantum particles to reach regions in space which are energetically not accessible according to classical mechanics. In this "tunneling region," the particle density is known to decay exponentially. This behavior is universal across all energy scales from nuclear physics to chemistry and solid state systems. Although typically only a small fraction of a particle wavefunction extends into the tunneling region, we present here an extreme quantum system: a gigantic molecule consisting of two helium atoms, with an 80% probability that its two nuclei will be found in this classical forbidden region...
December 6, 2016: Proceedings of the National Academy of Sciences of the United States of America
Takatoshi Yamada, Hiromitsu Kato, Yuki Okigawa, Masatou Ishihara, Masataka Hasegawa
Bilayer graphene was synthesized at low temperature using surface wave microwave plasma techniques where poly(methyl metacrylate) (PMMA) and methane (CH4) were used as carbon sources. Temperature-dependent Hall effect measurements were carried out in a helium atmosphere. Sheet resistance, sheet carrier density and mobility showed weak temperature dependence for graphene from PMMA, and the highest carrier mobility is 740 cm(2) V(-1) s(-1). For graphene from CH4, tunneling of the domain boundary limited carrier transport...
January 13, 2017: Nanotechnology
Mahadevappa Mahesh, Peter B Barker
No abstract text is available yet for this article.
December 2016: Journal of the American College of Radiology: JACR
Ming-Shuai Ding, Lin Tian, Wei-Zhong Han, Ju Li, Evan Ma, Zhi-Wei Shan
Helium bubbles are one of the typical radiation microstructures in metals and alloys, significantly influencing their deformation behavior. However, the dynamic evolution of helium bubbles under straining is less explored so far. Here, by using in situ micromechanical testing inside a transmission electron microscope, we discover that the helium bubble not only can coalesce with adjacent bubbles, but also can split into several nanoscale bubbles under tension. Alignment of the splittings along a slip line can create a bubble-free channel, which appears softer, promotes shear localization, and accelerates the failure in the shearing-off mode...
November 18, 2016: Physical Review Letters
S Kaliki, C L Shields
Although it is a relatively rare disease, primarily found in the Caucasian population, uveal melanoma is the most common primary intraocular tumor in adults with a mean age-adjusted incidence of 5.1 cases per million per year. Tumors are located either in iris (4%), ciliary body (6%), or choroid (90%). The host susceptibility factors for uveal melanoma include fair skin, light eye color, inability to tan, ocular or oculodermal melanocytosis, cutaneous or iris or choroidal nevus, and BRCA1-associated protein 1 mutation...
December 2, 2016: Eye
J M Muñoz Burgos, T Barbui, O Schmitz, D Stutman, K Tritz
Helium line-ratios for electron temperature (Te) and density (ne) plasma diagnostic in the Scrape-Off-Layer (SOL) and edge regions of tokamaks are widely used. Due to their intensities and proximity of wavelengths, the singlet, 667.8 and 728.1 nm, and triplet, 706.5 nm, visible lines have been typically preferred. Time-dependency of the triplet line (706.5 nm) has been previously analyzed in detail by including transient effects on line-ratios during gas-puff diagnostic applications. In this work, several line-ratio combinations within each of the two spin systems are analyzed with the purpose of eliminating transient effects to extend the application of this powerful diagnostic to high temporal resolution characterization of plasmas...
November 2016: Review of Scientific Instruments
T Barbui, M Krychowiak, R König, O Schmitz, J M Muñoz Burgos, B Schweer, A Terra
A beam emission spectroscopy system on thermal helium (He) and neon (Ne) has been set up at Wendelstein 7-X to measure edge electron temperature and density profiles utilizing the line-ratio technique or its extension by the analysis of absolutely calibrated line emissions. The setup for a first systematic test of these techniques of quantitative atomic spectroscopy in the limiter startup phase (OP1.1) is reported together with first measured profiles. This setup and the first results are an important test for developing the technique for the upcoming high density, low temperature island divertor regime...
November 2016: Review of Scientific Instruments
H B Ray, T M Biewer, D T Fehling, R C Isler, E A Unterberg
Fast visible cameras and a filterscope are used to examine the visible light emission from Oak Ridge National Laboratory's Proto-MPEX. The filterscope has been configured to perform helium line ratio measurements using emission lines at 667.9, 728.1, and 706.5 nm. The measured lines should be mathematically inverted and the ratios compared to a collisional radiative model (CRM) to determine Te and ne. Increasing the number of measurement chords through the plasma improves the inversion calculation and subsequent Te and ne localization...
November 2016: Review of Scientific Instruments
C C Klepper, T M Biewer, U Kruezi, S Vartanian, D Douai, D L Hillis, C Marcus
The detection limit for helium (He) partial pressure monitoring via the Penning discharge optical emission diagnostic, mainly used for tokamak divertor effluent gas analysis, is shown here to be possible for He concentrations down to 0.1% in predominantly deuterium effluents. This result from a dedicated laboratory study means that the technique can now be extended to intrinsically (non-injected) He produced as fusion reaction ash in deuterium-tritium experiments. The paper also examines threshold ionization mass spectroscopy as a potential backup to the optical technique, but finds that further development is needed to attain with plasma pulse-relevant response times...
November 2016: Review of Scientific Instruments
E Pasch, M N A Beurskens, S A Bozhenkov, G Fuchert, J Knauer, R C Wolf
This paper describes the design of the Thomson scattering system at the Wendelstein 7-X stellarator. For the first operation campaign we installed a 10 spatial channel system to cover a radial half profile of the plasma cross section. The start-up system is based on one Nd:YAG laser with 10 Hz repetition frequency, one observation optics, five fiber bundles with one delay line each, and five interference filter polychromators with five spectral channels and silicon avalanche diodes as detectors. High dynamic range analog to digital converters with 14 bit, 1 GS/s are used to digitize the signals...
November 2016: Review of Scientific Instruments
Peter J E M van der Linden, Marco Moretti Sala, Christian Henriquet, Matteo Rossi, Kenya Ohgushi, François Fauth, Laura Simonelli, Carlo Marini, Edmundo Fraga, Claire Murray, Jonathan Potter, Michael Krisch
We have developed a helium gas flow cryostat for use on synchrotron tender to hard X-ray beamlines. Very efficient sample cooling is achieved because the sample is placed directly in the cooling helium flow on a removable sample holder. The cryostat is compact and easy to operate; samples can be changed in less than 5 min at any temperature. The cryostat has a temperature range of 2.5-325 K with temperature stability better than 0.1 K. The very wide optical angle and the ability to operate in any orientation mean that the cryostat can easily be adapted for different X-ray techniques...
November 2016: Review of Scientific Instruments
B Lyu, J Chen, R J Hu, F D Wang, Y Y Li, J Fu, Y C Shen, M Bitter, K W Hill, L F Delgado-Aparicio, N Pablant, S G Lee, M Y Ye, Y J Shi, B N Wan
A two-crystal assembly was deployed on the tangential X-ray crystal spectrometer to measure both helium-like and hydrogen-like spectra on EAST. High-quality helium-like and hydrogen-like spectra were observed simultaneously for the first time on one detector for a wide range of plasma parameters. Profiles of line-integrated core ion temperatures inferred from two spectra were consistent. Since tungsten was adopted as the upper divertor material, one tungsten line (W XLIV at 4.017 Å) on the short-wavelength side of the Lyman-α line (Lα1) was identified for typical USN discharges, which was diffracted by a He-like crystal (2d = 4...
November 2016: Review of Scientific Instruments
W Yan, Z Y Chen, W Jin, S G Lee, Y J Shi, D W Huang, R H Tong, S Y Wang, Y N Wei, T K Ma, G Zhuang
An x-ray imaging crystal spectrometer has been developed on joint Texas experimental tokamak for the measurement of electron and ion temperatures from the Kα spectra of helium-like argon and its satellite lines. A two-dimensional multi-wire proportional counter has been applied to detect the spectra. The electron and ion temperatures have been obtained from the Voigt fitting with the spectra of helium-like argon ions. The profiles of electron and ion temperatures show the dependence on electron density in ohmic plasmas...
November 2016: Review of Scientific Instruments
S J Freethy, G D Conway, I Classen, A J Creely, T Happel, A Köhn, B Vanovac, A E White
Turbulent temperature fluctuations are measured on the ASDEX Upgrade tokamak using pairs of closely spaced, narrow-band heterodyne radiometer channels and a standard correlation technique. The pre-detection spacing and bandwidth of the radiometer channel pairs is chosen such that they are physically separated less than a turbulent correlation length, but do not overlap. The radiometer has 4 fixed filter frequency channels and two tunable filter channels for added flexibility in the measurement position. Relative temperature fluctuation amplitudes are observed in a helium plasma to be δT/T = (0...
November 2016: Review of Scientific Instruments
K Flesch, T Kremeyer, O Schmitz, V Soukhanovskii, U Wenzel
Direct measurements of the helium (He) fractional neutral pressure in the neutral gas around fusion devices is challenging because of the small mass difference between the abundant D2 molecules and the He ash which will be produced by deuterium-tritium fusion. To study He exhaust, an in situ Penning gauge system is being developed at UW-Madison that is optimized for good pressure and high spectroscopic sensitivity. Three different anode geometries have been studied regarding their vacuum electrostatic fields, light output, and ion current...
November 2016: Review of Scientific Instruments
K W Hill, M Bitter, L Delgado-Aparicio, P C Efthimion, R Ellis, L Gao, J Maddox, N A Pablant, M B Schneider, H Chen, S Ayers, R L Kauffman, A G MacPhee, P Beiersdorfer, R Bettencourt, T Ma, R C Nora, H A Scott, D B Thorn, J D Kilkenny, D Nelson, M Shoup, Y Maron
A high resolution (E/ΔE = 1200-1800) Bragg crystal x-ray spectrometer is being developed to measure plasma parameters in National Ignition Facility experiments. The instrument will be a diagnostic instrument manipulator positioned cassette designed mainly to infer electron density in compressed capsules from Stark broadening of the helium-β (1s(2)-1s3p) lines of krypton and electron temperature from the relative intensities of dielectronic satellites. Two conically shaped crystals will diffract and focus (1) the Kr Heβ complex and (2) the Heα (1s(2)-1s2p) and Lyα (1s-2p) complexes onto a streak camera photocathode for time resolved measurement, and a third cylindrical or conical crystal will focus the full Heα to Heβ spectral range onto an image plate to provide a time integrated calibration spectrum...
November 2016: Review of Scientific Instruments
Daniel Leicht, Matin Kaufmann, Raffael Schwan, Jan Schäfer, Gerhard Schwaab, Martina Havenith
The IR spectrum of benzyl radical:water clusters was recorded. Benzyl radicals were produced by vacuum flash pyrolysis and trapped in superfluid helium nanodroplets. The infrared spectrum of benzyl radical water aggregates in the range 2585-2820 cm(-1) was recorded by subsequent addition of deuterated water. A total of seven peaks are observed at 2766, 2750, 2656, 2638, 2633, 2598, and 2593 cm(-1). Based on pressure dependent measurements and comparison to accompanying ab initio calculations, five of these bands are assigned to distinct O-D stretch vibrations of benzyl:water clusters with one and two water molecules...
November 28, 2016: Journal of Chemical Physics
Thomas-C Jagau
The theory and implementation of the complex-scaled coupled-cluster method with singles and doubles excitations (cs-CCSD) for studying resonances induced by static electric fields are presented. Within this framework, Stark shifts and ionization rates are obtained directly from the real and imaginary parts of the complex energy. The method is applied to the ground states of hydrogen, helium, lithium, beryllium, neon, argon, and carbon at varying field strengths. Complex-scaled Hartree-Fock, second-order many-body perturbation theory, and CCSD results are reported and analyzed with a focus on the impact of electron correlation on the ionization process...
November 28, 2016: Journal of Chemical Physics
Dong K Shin, Bryce M Henson, Roman I Khakimov, Jacob A Ross, Colin J Dedman, Sean S Hodgman, Kenneth G H Baldwin, Andrew G Truscott
We have developed and characterised a stable, narrow linewidth external-cavity laser (ECL) tunable over 100 nm around 1080 nm, using a single-angled-facet gain chip. We propose the ECL as a low-cost, high-performance alternative to fibre and diode lasers in this wavelength range and demonstrate its capability through the spectroscopy of metastable helium. Within the coarse tuning range, the wavelength can be continuously tuned over 30 pm (7.8 GHz) without mode-hopping and modulated with bandwidths up to 3 kHz (piezo) and 37(3) kHz (current)...
November 28, 2016: Optics Express
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