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high frequency jet

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
Chung-Che Wu, Marcel Burger, Detlef Günther, Chuan-Chou Shen, Bodo Hattendorf
This work presents a high-sensitivity approach to quantify ultra-trace concentrations of rare earth elements (REEs) in speleothem carbonates using open-cell laser ablation-sector field-inductively coupled plasma mass spectrometry (open-cell LA-SF-ICPMS). Specifically, open-cell LA in combination with a gas exchange device enabled sampling of large-scale carbonate specimens in an ambient environment. The use of a "jet" vacuum interface and the addition of small amounts of N2 gas allowed for a 20-40 fold sensitivity enhancement compared to the conventional interface configuration...
August 14, 2018: Analytica Chimica Acta
Caiyi Xiong, Yong Jiang
Shear layer effect was pointed out to be associated with the vortex-flame interaction and leads to the difference in combustion noise. In this work, numerical simulation combining with an acoustic analogy equation was performed to investigate the shear layer effect on the sound generation by jet diffusion flames. To easily identify the cause and effect, the approach that varies the thickness of shear layer by changing the Prandtl number is adopted, which provides deeper physical insight into the characteristics of the acoustic near field...
March 2018: Journal of the Acoustical Society of America
Wolfgang Hohenforst-Schmidt, Paul Zarogoulidis, Haidong Huang, Yan-Gao Man, Stella Laskou, Charilaos Koulouris, Dimitris Giannakidis, Stylianos Mantalobas, Maria C Florou, Aikaterini Amaniti, Michael Steinheimer, Anil Sinha, Lutz Freitag, J Francis Turner, Robert Browning, Thomas Vogl, Andrei Roman, Naim Benhassen, Isaak Kesisoglou, Konstantinos Sapalidis
We use pulmonary interventional procedures for the diagnosis of pulmonary diseases either for benign or malignant lesions. Flexible bronchoscopy with or without radial endobronchial ultrasound, convex-probe endobronchial ultrasound and electromagnetic navigation are procedures performed in centers with experience in diagnostic pulmonary medicine. The method of sedation and ventilation is very important in order to avoid or handle with success complications. Proper respiration during pulmonary (or other interventional) procedures is a key factor...
2018: Journal of Cancer
Libor Trško, František Nový, Otakar Bokůvka, Michal Jambor
Ultrasonic fatigue testing is one of a few methods which allow investigating fatigue properties in the ultra-high cycle region. The method is based on exposing the specimen to longitudinal vibrations on its resonance frequency close to 20 kHz. With use of this method, it is possible to significantly decrease the time required for the test, when compared to conventional testing devices usually working at frequencies under 200 Hz. It is also used to simulate loading of material during operation in high speed conditions, such as those experienced by components of jet engines or car turbo pumps...
March 7, 2018: Journal of Visualized Experiments: JoVE
Ajay P Anvekar, Piyush S Shah, Elizabeth A Nathan, Dorota A Doherty, Sanjay K Patole, Karen N Simmer
OBJECTIVE: To assess if high frequency jet ventilation (HFJV) is associated with reduced odds of death or discharge home on oxygen in preterm infants. METHODS: A case control study (1 February 2010 - 1 June 2014) comparing the primary outcome as "death or discharge home on oxygen" in preterm infants who needed HFJV (Cases) versus those who did not (Controls). Controls were matched to cases (1:1) on gestation, birthweight, gender, place of birth, growth status, antenatal glucocorticoids, and dexamethasone as treatment for severe bronchopulmonary dysplasia (BPD)...
March 20, 2018: Journal of Maternal-fetal & Neonatal Medicine
Thea Buchan, Miles Walkden, Kathryn Jenkins, Pervez Sultan, Steve Bandula
AIM: To evaluate the effect of high-frequency jet ventilation (HFJV) in place of standard intermittent positive-pressure ventilation (IPPV) on procedure duration, patient radiation dose, complication rates, and outcomes during CT-guided cryoablation of small renal tumours. MATERIALS AND METHODS: One hundred consecutive CT-guided cryoablation procedures to treat small renal tumours under general anaesthesia were evaluated-50 with standard IPPV and 50 after the introduction of HFJV as standard practice...
March 7, 2018: Cardiovascular and Interventional Radiology
Daniela V Pachito, Alan L Eckeli, Ahmed S Desouky, Mark A Corbett, Timo Partonen, Shantha Mw Rajaratnam, Rachel Riera
BACKGROUND: Exposure to light plays a crucial role in biological processes, influencing mood and alertness. Daytime workers may be exposed to insufficient or inappropriate light during daytime, leading to mood disturbances and decreases in levels of alertness. OBJECTIVES: To assess the effectiveness and safety of lighting interventions to improve alertness and mood in daytime workers. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, seven other databases; ClinicalTrials...
March 2, 2018: Cochrane Database of Systematic Reviews
Sander Bekeschus, Anke Schmidt, Axel Kramer, Hans-Robert Metelmann, Frank Adler, Thomas von Woedtke, Felix Niessner, Klaus-Dieter Weltmann, Kristian Wende
Promising cold physical plasma sources have been developed in the field of plasma medicine. An important prerequisite to their clinical use is lack of genotoxic effects in cells. During optimization of one or even different plasma sources for a specific application, large numbers of samples need to be analyzed. There are soft and easy-to-assess markers for genotoxic stress such as phosphorylation of histone H2AX (γH2AX) but only few tests are accredited by the OECD with regard to mutagenicity detection. The micronucleus (MN) assay is among them but often requires manual counting of many thousands of cells per sample under the microscope...
February 8, 2018: Environmental and Molecular Mutagenesis
Xiaotao Geng, Shiyang Zhong, Guanglong Chen, Weijun Ling, Xinkui He, Zhiyi Wei, Dong Eon Kim
Generation of high-order harmonics (HHs) is intensified by using a plasma waveguide created by a laser in a clustered gas jet. The formation of a plasma waveguide and the guiding of a laser beam are also demonstrated. Compared to the case without a waveguide, harmonics were strengthened up to nine times, and blue-shifted. Numerical simulation by solving the time-dependent Schrödinger equation in strong field approximation agreed well with experimental results. This result reveals that the strengthening is the result of improved phase matching and that the blue shift is a result of change in fundamental laser frequency due to self-phase modulation (SPM)...
February 5, 2018: Optics Express
Paul S Hsu, Naibo Jiang, Paul M Danehy, James R Gord, Sukesh Roy
Transmission of intense ultrashort laser pulses through hollow-core fibers (HCFs) is investigated for molecular-tagging velocimetry. A low-vacuumed HCF beam-delivery system is developed to transmit high-peak-power pulses. Vacuum pressure effects on transmission efficiency and nonlinear effects at the fiber output are studied for 100 ps and 100 fs laser beams. With a 0.1 bar vacuum in the fiber, transmission efficiency increases by ∼30%, while spectral broadening is reduced. A 1 m long, 1 mm core metal-dielectric-coated HCF can transmit ∼45  mJ/pulse and ∼2...
January 20, 2018: Applied Optics
B-B Zhang, B Zhang, H Sun, W-H Lei, H Gao, Y Li, L Shao, Y Zhao, Y-D Hu, H-J Lü, X-F Wu, X-L Fan, G Wang, A J Castro-Tirado, S Zhang, B-Y Yu, Y-Y Cao, E-W Liang
Double neutron star (DNS) merger events are promising candidates of short gamma-ray burst (sGRB) progenitors as well as high-frequency gravitational wave (GW) emitters. On August 17, 2017, such a coinciding event was detected by both the LIGO-Virgo gravitational wave detector network as GW170817 and Gamma-Ray Monitor on board NASA's Fermi Space Telescope as GRB 170817A. Here, we show that the fluence and spectral peak energy of this sGRB fall into the lower portion of the distributions of known sGRBs. Its peak isotropic luminosity is abnormally low...
January 31, 2018: Nature Communications
Demet Altun, Emre Çamcı, Mukadder Orhan-Sungur, Nükhet Sivrikoz, Bora Başaran, Tülay Özkan-Seyhan
No abstract text is available yet for this article.
January 17, 2018: Auris, Nasus, Larynx
Oliver McRae, Antoine Gaillard, James C Bird
When air is blown in a straw or tube near an air-liquid interface, typically one of two behaviors is observed: a dimple in the liquid's surface, or a frenzy of sputtering bubbles, waves, and spray. Here we report and characterize an intermediate regime that can develop when a confined air jet enters the interface at an angle. This regime is oscillatory with a distinct characteristic frequency and can develop periodic angled jets that can break up into monodisperse aerosols. The underlying mechanisms responsible for this highly periodic regime are not well understood...
July 2017: Physical Review. E
R Pausch, M Bussmann, A Huebl, U Schramm, K Steiniger, R Widera, A Debus
For the relativistic Kelvin-Helmholtz instability (KHI), which occurs at shear interfaces between two plasma streams, we report results on the polarized radiation over all observation directions and frequencies emitted by the plasma electrons from ab initio kinetic simulations. We find the polarization of the radiation to provide a clear signature for distinguishing the linear phase of the KHI from its other phases. During the linear phase, we predict the growth rate of the KHI radiation power to match the growth rate of the KHI to a high degree...
July 2017: Physical Review. E
Anthony Roucou, Isabelle Kleiner, Manuel Goubet, Sabath Bteich, Gael Mouret, Robin Bocquet, Francis Hindle, W Leo Meerts, Arnaud Cuisset
The monitoring of gas-phase mononitrotoluenes is crucial for defence, civil security and environmental interests because they are used as taggant for TNT detection and in the manufacturing of industrial compounds such as dyestuffs. In this study, we have succeeded to measure and analyse at high-resolution a room temperature rotationally resolved millimetre-wave spectrum of meta-nitrotoluene (3-NT). Experimental and theoretical difficulties have been overcome, in particular, those related to the low vapour pressure of 3-NT and to the presence of a CH3 internal rotation in an almost free rotation regime (V3 =6...
January 12, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Maria Wilson, Jens Ådne Rekkedal Haga, Hans Erik Karlsen
Attacks by aquatic predators generate frontal water disturbances characterised by low-frequency gradients in pressure and particle motion. Low-frequency hearing is highly developed in cephalopods. Thus, we examined behavioural responses in juvenile cuttlefish to infrasonic accelerations mimicking main aspects of the hydrodynamic signals created by predators. In the experimental set-up, animals and their surrounding water moved as a unit to minimise lateral line activation and to allow examination of the contribution by the inner ear...
January 11, 2018: Journal of Experimental Biology
Pavol Mikolka, Jana Kopincova, Petra Kosutova, Maros Kolomaznik, Andrea Calkovska, Daniela Mokra
AIM: Meconium aspiration syndrome (MAS) is life-threatening respiratory failure of newborns which can be treated by exogenous surfactant. In response to meconium, increased levels of chemokine IL-8 (CXCL8) stimulate massive neutrophil infiltration of the lungs. Local accumulation and activation of neutrophils, on-going inflammation, lung edema, and oxidative damage contribute to inactivation of endogenous and therapeutically given surfactants. Therefore, we have hypothesized that addition of monoclonal anti-IL-8 antibody into exogenous surfactant can mitigate the neutrophil-induced local injury and the secondary surfactant inactivation and may finally result in improvement of respiratory functions...
February 2018: Experimental Lung Research
Kirstin D Doney, Dongfeng Zhao, Harold Linnartz
We present a combined experimental and ab initio study on the jet-cooled high-resolution infrared spectra of the ν1 (acetylenic stretch) fundamental band for three isotopologues of propyne:13 CH3 12 C≡12 CH,12 CH3 13 C≡12 CH, and12 CH3 12 C≡13 CH. The experimental spectra are recorded in natural abundance using a continuous supersonic expansion of regular propyne diluted in argon and helium, in combination with continuous wave cavity ring-down spectroscopy (cw-CRDS). The fully rotationally resolved K' = 0 and 1 subbands of all three monosubstituted13 C isotopologues have been measured near 3330 cm-1 , and their spectroscopic analysis is presented here for the first time...
January 18, 2018: Journal of Physical Chemistry. A
Francesco Mora, Francesco Missale, Fabiola Incandela, Marta Filauro, Giampiero Parrinello, Alberto Paderno, Palmiro Della Casa, Cesare Piazza, Giorgio Peretti
Background: Transoral laser microsurgery (TLM) for early to intermediate laryngeal squamous cell cancer (SCC) can be technically challenging when adequate exposure of the posterior laryngeal compartment is required due to the presence of the orotracheal tube. The goal of our study was to analyze the efficacy of high frequency jet ventilation (HFJV) in achieving appropriate laryngeal exposure and safe oncologic resection of lesions located in such a position. Methods: We reviewed the clinical records of 62 patients affected by Tis-T2 SCC of the posterior laryngeal compartment treated by TLM between 02/2012 and 12/2016...
2017: Frontiers in Oncology
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