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Helium/oxygen Mixture (oxygen + mixture)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

Calibration of three capnographs for use with helium and oxygen gas mixtures,

ANAESTHESIA, Issue 2 2003
J. A. S. Ball
Summary Capnography is considered essential in the management of mechanically-ventilated patients. Helium, as an adjunct to mechanical ventilation, is the subject of renewed interest and used increasingly. However, helium affects the performance of infrared capnometry. We constructed a simple device to generate variable mixtures of helium, oxygen and carbon dioxide within the normal physiological range, and tested the performance of two side-stream and one in-line capnographs. We found that addition of helium to the gas mixture caused all three capnographs to underestimate the concentration of carbon dioxide. The underestimation increased as the proportion of helium increased. The maximum underestimation (30%) occurred in a 79:21 helium/oxygen mixture. [source]

Hybrid Sputtering-Remote PECVD Deposition of Au Nanoparticles on SiO2 Layers for Surface Plasmon Resonance-Based Colored Coatings

PLASMA PROCESSES AND POLYMERS, Issue 8 2010
Haile Takele Beyene
Abstract In this paper, a hybrid system consisting of metal nano-particles dispersed on the surface of a dielectric layer is presented: a remote Expanding Thermal Plasma CVD system is used for the deposition of the inorganic (i.e. SiO2) layers from hexamethyldisiloxane/oxygen mixtures in combination with an rf magnetron sputtering tool for the deposition of metallic (i.e. gold) nanoparticles on top of the SiO2 layers. The optical properties of the Au/SiO2 layers have been investigated by means of UV-VIS-NIR variable angle spectroscopic ellipsometry. Rutherford backscattering and transmission electron microscopy were used to determine the film density, the nanoparticle size and its distribution, respectively. The uniform distribution of gold nanoparticles on the surface of the SiO2 layers allows obtaining red- to blue- colored coatings as a consequence of the shift of the surface plasmon resonance band to higher wavelengths, caused by an increase in size of nanoparticles and metal surface coverage. [source]

Mechanistic Study of Partial Oxidation of Methane to Syngas Using In Situ Time-Resolved FTIR and Microprobe Raman Spectroscopies

THE CHEMICAL RECORD, Issue 2 2002
Mechanism of Methane Partial Oxidation
Abstract In situ time-resolved Fourier transform infrared (FTIR) and microprobe Raman spectroscopies were used to characterize the reaction mechanisms of the partial oxidation of methane to syngas over SiO2 - and ,-Al2O3 -supported rhodium and ruthenium catalysts. The interaction of both pure methane and a methane/oxygen mixture at a stoichiometric feed ratio with an oxygen-rich catalyst surface led to the formation of CO2 and H2O as the primary products. For the H2 -pretreated samples, the reaction mechanisms with the catalysts differ. Only Rh/SiO2 is capable of catalyzing the direct oxidation of methane to syngas, while syngas formation over Rh/g-Al2O3, Ru/SiO2, and Ru/g-Al2O3 can be achieved mainly via a combustion-reforming scheme. The significant difference in the mechanisms for partial oxidation of methane to syngas over the catalysts can be correlated to the differences in the concentration of oxygen species (O2,) on the catalyst surface during the reaction, mainly due to the difference in the nature of the metals and supports. © 2002 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 2:102,112, 2002: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.10016 [source]

Options in Prehospital analgesia

EMERGENCY MEDICINE AUSTRALASIA, Issue 1 2002
Meredith L Borland
Abstract Background: Prehospital analgesia options for paramedics have been limited due to the difficulty in achieving safe and effective pain relief without compromising transportation to hospital. The present paper identifies the analgesia methods currently available in the prehospital setting so as to evaluate the various options and highlight areas for future research. Methods: A literature review of Medline and Embase databases from 1966 until the present was undertaken. Further hand searching of all the references identified in these papers was also performed. All current literature was analysed and categorized according to one of four levels of evidence using National Health and Medical Research Council of Australia guidelines (1999). Results: There is a paucity of randomized control trials relating to prehospital analgesia. All published literature was level III or IV prospective or retrospective studies. Drug options used included nitrous oxide/oxygen mixtures, intravenous/intramuscular nalbuphine, intravenous tramadol and intravenous pure opiate agonists. Conclusions: The evidence supporting analgesic options in the prehospital setting is limited. There are few published data in this area despite the inadequacy of pain relief being recognized as a weakness in prehospital care. Prehospital analgesia is an area worthy of innovative methods for the administration of safe and effective analgesics without significant impact on transport times. Such methods should be prospectively evaluated in well-constructed trials. [source]

Crystalline bismuth oxide nanorods fabricated on Pt-coated substrates using a trimethylbismuth and oxygen mixture

CRYSTAL RESEARCH AND TECHNOLOGY, Issue 7 2008
Hyoun Woo Kim
Abstract The current work reports the fabrication of crystalline Bi2O3 nanorods on Pt-coated Si substrates using trimethylbismuth and O2 as the bismuth and the oxygen sources, respectively, in the metalorganic chemical vapor deposition process. Their microstructures were characterized by scanning electron microscopy, X-ray diffraction, and transmission electron microscopy. The obtained nanorods were crystalline, with their diameters in the range of 20,200 nm. The absence of tip-nanoparticle and the presence of predeposited Bi2O3 layer indicated that the growth was dominated by a vapor-solid process. The photoluminescence measurements of the Bi2O3 nanorods at room temperature exhibited an emission band peaked at around 422 nm. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Respiratory problems in Accident and Emergency , the role of helium,oxygen mixtures

ANAESTHESIA, Issue 5 2009
P. Bathke
No abstract is available for this article. [source]