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Mariusz Ślachciński
The Flow Focusing Pneumatic Nebulizer (FFPN) working at low liquid flow rates was evaluated for the elemental analysis in slurried samples by argon-helium microwave induced plasma optical emission spectrometry (MIP-OES). The obtained results achieved were compared with commercially available V-groove Babington type nebulizer (VBPN). A univariate approach and the simplex optimization procedure were used to achieve optimized conditions and derive analytical figures of merit. Analytical performance of the micro nebulization system was characterized by a determination of the limits of detection (LODs), the precision (RSDs) and the wash-out times for Ba, Ca, Cd, Cu, Fe, Mg, Mn, Pb and Sr...
December 1, 2016: Talanta
Johan van der Meer, André Pampel, Eus van Someren, Jennifer Ramautar, Ysbrand van der Werf, German Gomez-Herrero, Jöran Lepsien, Lydia Hellrung, Hermann Hinrichs, Harald Möller, Martin Walter
This data set contains electroencephalography (EEG) data as well as simultaneous EEG with functional magnetic resonance imaging (EEG/fMRI) data. During EEG/fMRI, the EEG cap was outfitted with a hardware-based add-on consisting of carbon-wire loops (CWL). These yielded six extra׳CWL׳ signals related to Faraday induction of these loops in the main magnetic field "Measurement and reduction of motion and ballistocardiogram artefacts from simultaneous EEG and fMRI recordings" (Masterton et al., 2007) [1]. In this data set, the CWL data make it possible to do a direct regression approach to deal with the BCG and specifically He artifact...
June 2016: Data in Brief
C F Barenghi, Y A Sergeev, A W Baggaley
Experiments and numerical simulations of turbulent (4)He and (3)He-B have established that, at hydrodynamic length scales larger than the average distance between quantum vortices, the energy spectrum obeys the same 5/3 Kolmogorov law which is observed in the homogeneous isotropic turbulence of ordinary fluids. The importance of the 5/3 law is that it points to the existence of a Richardson energy cascade from large eddies to small eddies. However, there is also evidence of quantum turbulent regimes without Kolmogorov scaling...
October 20, 2016: Scientific Reports
Andrew P Storey, Offer M Zeiri, Steven J Ray, Gary M Hieftje
The flowing atmospheric-pressure afterglow (FAPA) source was used for the mass-spectrometric analysis of vapor samples introduced between the source and mass spectrometer inlet. Through interrupted operation of the plasma-supporting helium flow, helium consumption is greatly reduced and dynamic gas behavior occurs that was characterized by schlieren imaging. Moreover, mass spectra acquired immediately after the onset of helium flow exhibit a signal spike before declining and ultimately reaching a steady level...
October 18, 2016: Journal of the American Society for Mass Spectrometry
Elena Redchenko, Mikhail Lemeshko
We study a polar molecule immersed in a superfluid environment, such as a helium nanodroplet or a Bose-Einstein condensate, in the presence of a strong electrostatic field. We show that coupling of the molecular pendular motion, induced by the field, to the fluctuating bath leads to formation of pendulons -- spherical harmonic librators dressed by a field of many-particle excitations. We study the behavior of the pendulon in a broad range of molecule-bath and molecule-field interaction strengths, and reveal that its spectrum features a series of instabilities which are absent in the field-free case of the angulon quasiparticle...
October 18, 2016: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Marko Melander, Elvar Örn Jónsson, Jens Jørgen Mortensen, Tejs Vegge, Juan María García Lastra
Combining constrained density function theory (cDFT) with Marcus theory is an efficient and promising way to address charge transfer reactions. Here, we present a general and robust implementation of cDFT within the projector augmented wave (PAW) framework. PAW pseudopotentials offer a reliable frozen-core electron description across the whole periodic table, with good transferability, as well as facilitate the extraction of all-electron quantities. The present implementation is applicable to two different wave function representations -- atomic centred basis sets (LCAO) and the finite-difference (FD) approximation utilizing real-space grids...
October 17, 2016: Journal of Chemical Theory and Computation
Kenion H Blakeman, Craig A Cavanaugh, William M Gilliland, J Michael Ramsey
RATIONALE: There are many chemical measurement scenarios that would benefit from hand portable mass spectrometry tools including forensics, environmental monitoring, and safety and security. High pressure mass spectrometry (HPMS) facilitates miniaturization by significantly reducing vacuum system requirements. Previous work demonstrated HPMS using helium buffer gas, but HPMS conducted using ambient air would further reduce the size and weight of a portable instrument while also reducing logistical demands by eliminating the need for a helium supply...
October 17, 2016: Rapid Communications in Mass Spectrometry: RCM
Deborah Azrael, Alexander Mukamal, Amy P Cohen, David Gunnell, Catherine Barber, Matthew Miller
INTRODUCTION: Identifying the source and specific type of gas used in suicides is difficult using most data systems owing to limitations in ICD-10 coding. The National Violent Death Reporting System (NVDRS), with its rich collection of both coded and free-text variables, has the potential to overcome these limitations. This study used a multipronged approach to identify gas-specific suicides in NVDRS and to track the incidence of these suicides over time. METHODS: Using suicide cases from the 16 NVDRS states that participated throughout 2005-2012, free-text and code searches were conducted for four types of variables-incident narratives, coroner/medical examiner cause-of-death statements, cause-of-death codes, and substance names-to identify suicides by carbon monoxide, helium, hydrogen sulfide, and four other gases...
November 2016: American Journal of Preventive Medicine
Moritz Flick, Martin Albrecht, Gezina T M L Oei, Renske Steenstra, Raphaela P Kerindongo, Coert J Zuurbier, Hemal H Patel, Markus W Hollmann, Benedikt Preckel, Nina C Weber
Caveolae, lipid enriched invaginations of the plasma membrane, are epicentres of cellular signal transduction. The structural proteins of caveolae, caveolins, regulate effector pathways in anaesthetic-induced cardioprotection, including the RISK pathway. Helium (He) postconditioning (HePoc) is known to mimic anaesthetic conditioning and to prevent damage from myocardial infarction. We hypothesize that HePoc regulates caveolin-1 and caveolin-3 (Cav-1 and Cav-3) expression in the rat heart and activates the RISK pathway...
October 11, 2016: European Journal of Pharmacology
Luke J Higgins, Cristian A Marocico, Vasilios D Karanikolas, Alan P Bell, John J Gough, Graham P Murphy, Peter J Parbrook, A Louise Bradley
A range of seven different Ag plasmonic arrays formed using nanostructures of varying shape, size and gap were fabricated using helium-ion lithography (HIL) on an InGaN/GaN quantum well (QW) substrate. The influence of the array geometry on plasmon-enhanced Förster resonance energy transfer (FRET) from a single InGaN QW to a ∼80 nm layer of CdSe/ZnS quantum dots (QDs) embedded in a poly(methyl methacrylate) (PMMA) matrix is investigated. It is shown that the energy transfer efficiency is strongly dependent on the array properties and an efficiency of ∼51% is observed for a nanoring array...
October 14, 2016: Nanoscale
Kirsten F Smit, Daniel Brevoord, Stefan De Hert, Bas A de Mol, Raphaela P Kerindongo, Susan van Dieren, Wolfgang S Schlack, Markus W Hollmann, Nina C Weber, Benedikt Preckel
BACKGROUND: The noble gas helium induces pre- and postconditioning in animals and humans. Volatile anesthetics induce cardioprotection in humans undergoing coronary artery bypass graft (CABG) surgery. We hypothesized that helium induces pre- and postconditioning in CABG-patients, affecting signaling molecules protein kinase C-epsilon (PKC-ε), p38 mitogen activated protein kinase (p38 MAPK), extracellular signal-regulated kinase 1/2 (ERK-1/2) and heat shock protein 27 (HSP-27) within cardiac tissue, and reducing postoperative troponin levels...
October 14, 2016: Journal of Translational Medicine
Philippe Jolliet, Lamia Ouanes-Besbes, Fekri Abroug, Jalila Ben Khelil, Mohamed Besbes, Aude Garnero, Jean-Michel Arnal, Fabrice Daviaud, Jean-Daniel Chiche, Benoît Lortat-Jacob, Jean-Luc Diehl, Nicolas Lerolle, Alain Mercat, Keyvan Razazi, Christian Brun-Buisson, Isabelle Durand-Zaleski, Joëlle Texereau, Laurent Brochard
RATIONALE: During non-invasive ventilation (NIV) for COPD exacerbations, Helium/Oxygen (He/O2) reduces work of breathing and hypercapnia more than Air/O2 but impact on clinical outcome remains unknown. OBJECTIVE: To determine whether continuous administration of He/O2 for 72 hours, during and in-between NIV sessions, is superior to Air/O2 in reducing NIV failure (25% to 15%) in severe hypercapnic COPD exacerbations. METHODS: Prospective, randomized, open-label trial (16 intensive care units, 6 countries)...
October 13, 2016: American Journal of Respiratory and Critical Care Medicine
C Bopp, R Hirayama, T Inaniwa, A Kitagawa, N Matsufuji, K Noda
Ion beams present a potential advantage in terms of treatment of lesions with hypoxic regions. In order to use this potential, it is important to accurately model the cell survival of oxic as well as hypoxic cells. In this work, an adaptation of the microdosimetric kinetic (MK) model making it possible to account for cell hypoxia is presented. The adaptation relies on the modification of damage quantity (double strand breaks and more complex lesions) due to the radiation. Model parameters such as domain size and nucleus size are then adapted through a fitting procedure...
October 7, 2016: Physics in Medicine and Biology
Arnau Vilà, Miguel González
The influence of the mass in the photodissociation dynamics of a homonuclear diatomic molecule (X2), embedded in a superfluid helium nanodroplet (T = 0.37 K) of 300 atoms, has been investigated using a hybrid quantum dynamics method recently proposed by us. Several hypothetical isotopic variants of Cl2 have been examined in order to make possible the analysis of a wide diversity of masses (mX: 0.25mCl-1.50mCl). This is probably the first time that this problem has been considered theoretically. The photodissociation mechanism of X2(B) is very similar to that of Cl2(B) and the efficiency of the X2-helium energy exchange mechanism can be so great that it leads to the full and partial (≈86%) geminate recombination for the lower masses explored (mX = 0...
October 5, 2016: Physical Chemistry Chemical Physics: PCCP
Matin Kaufmann, Daniel Leicht, Raffael Schwan, Devendra Mani, Gerhard Schwaab, Martina Havenith
Infrared absorption spectra of glycine and glycine-water aggregates embedded in superfluid helium nanodroplets were recorded in the frequency range 1000-1450 cm(-1). For glycine monomer, absorption bands were observed at 1106 cm(-1), 1134 cm(-1), and 1389 cm(-1). These bands were assigned to the C-OH stretch mode of the glycine conformers I, III and II, respectively. For glycine-water aggregates, we observed two bands at 1209 cm(-1) and 1410 cm(-1) which we assign to distinct conformers of glycine-H2O. In all cases, the water is found to preferentially bind to the carboxyl group of the glycine...
October 12, 2016: Physical Chemistry Chemical Physics: PCCP
P Moroshkin, R Batulin, P Leiderer, K Kono
We investigate the motion of electrically charged metallic nano- and microparticles produced by laser ablation in He gas and injected into superfluid helium. In the presence of a vertical static electric field, the particles either perform a repetitive shuttle-like motion transporting the charge across the liquid-gas interface or become trapped under the free surface of liquid He and coalesce into long filaments and complex two-dimensional mesoscopic networks. A classical electrohydrodynamic model is used to describe the motion of charged microparticles in superfluid He...
September 29, 2016: Physical Chemistry Chemical Physics: PCCP
Neil U M Howes, James P A Lockhart, Mark A Blitz, Scott A Carr, Maria Teresa Baeza-Romero, Dwayne E Heard, Robin J Shannon, Paul W Seakins, T Varga
Using laser flash photolysis coupled to photo-ionization time-of-flight mass spectrometry (PIMS), methyl radicals (CH3) have been detected as primary products from the reaction of OH radicals with acetaldehyde (ethanal, CH3CHO) with a yield of ∼15% at 1-2 Torr of helium bath gas. Supporting measurements based on laser induced fluorescence studies of OH recycling in the OH/CH3CHO/O2 system are consistent with the PIMS study. Master equation calculations suggest that the origin of the methyl radicals is from prompt dissociation of chemically activated acetyl products and hence is consistent with previous studies which have shown that abstraction, rather than addition/elimination, is the sole route for the OH + acetaldehyde reaction...
September 29, 2016: Physical Chemistry Chemical Physics: PCCP
Yue-Cun Wang, Lin Tian, Fan Liu, Yuan-Bin Qin, Gong Zheng, Jing-Tao Wang, Evan Ma, Zhi-Wei Shan
Silicon is used as a prominent case to demonstrate the dramatic effects of helium ion microscope nanofabrication. Structurally, a submicrometer Si pillar can turn completely amorphous at He(+) doses typically used for micromachining, forming nanobubbles at higher doses. In terms of mechanical properties, the flow stress decreases markedly with increasing dosage, and the softened amorphous Si exhibits spread-out plastic flow.
October 6, 2016: Small
S I Zaichkina, A R Dyukina, O M Rozanova, S P Romanchenko, N P Sirota, E A Kuznetsova, N B Simonova, S S Sorokina, D T Zakrzhevskaya, V I Yusupov, V N Bagratishvili
We studied the effect of exposure to helium-neon laser (dose range 0.16-50 mJ/cm(2)) on activation of natural protection reserve in mice using the adaptive response test. DNA comets method revealed a protective response manifested in DNA damage level in whole blood leukocytes of mice and in lymphoid organs by the thymus and spleen weight index; preexposure to laser did not induce the adaptive response. ROS level in the whole blood was assessed by the level of zymosan-induced luminol chemiluminescence. In mice subjected to adaptive laser irradiation in doses of 0...
September 2016: Bulletin of Experimental Biology and Medicine
Lukas Ebner, Jeff Kammerman, Bastiaan Driehuys, Mark L Schiebler, Robert V Cadman, Sean B Fain
In the last two decades, functional imaging of the lungs using hyperpolarized noble gases has entered the clinical stage. Both helium ((3)He) and xenon ((129)Xe) gas have been thoroughly investigated for their ability to assess both the global and regional patterns of lung ventilation. With advances in polarizer technology and the current transition towards the widely available (129)Xe gas, this method is ready for translation to the clinic. Currently, hyperpolarized (HP) noble gas lung MRI is limited to selected academic institutions; yet, the promising results from initial clinical trials have drawn the attention of the pulmonary medicine community...
September 16, 2016: European Journal of Radiology
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