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Molecular Water (molecular + water)

Distribution by Scientific Domains

Chemistry	50%

Selected Abstracts

Lower airway humidification in spontaneously breathing tracheostomized patients: Comparative study of trachea spray versus heated humidifier

HEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 5 2008
Tilman Keck MD
Abstract Background. Our aim was to compare inhalation with molecular water (vaporizing humidifier) and particulate water (trachea spray) in spontaneously breathing tracheostomized patients. Methods. We performed a randomized, 2-way crossover study and a prospective, comparative, nonblinded study. Tracheal humidity and temperature were measured before and after use of a humidifier and spray for 1 week. Results. After both inhalation and spray, the tracheal temperature and total water content increased significantly (study 1). The temperature gradient between ambient and tracheal air was significantly higher after spray, but not after inhalation (study 2). The water gradient increased nonsignificantly after spray and inhalation. The water gradient after inhalation or spray did not differ significantly. Conclusions. Molecular water is not superior to particulate water because of temperature and humidity increase after both forms of water delivery. Because of its easy use, portability, and moisturizing effect, a trachea spray may offer additional options in postoperative tracheostomy care. © 2007 Wiley Periodicals, Inc. Head Neck, 2008 [source]

Raman microscopy of the mixite mineral BiCu6(AsO4)3(OH)6·3H2O from the Czech Republic

JOURNAL OF RAMAN SPECTROSCOPY, Issue 5 2010
Ray L. Frost
Abstract Raman microscopy of the mixite mineral BiCu6(AsO4)3(OH)6·3H2O from Jáchymov and from Smrkovec (both Czech Republic) has been used to study their molecular structure. The presence of (AsO4)3,, (AsO3OH)2,, (PO4)3, and (PO3OH)2, units, as well as molecular water and hydroxyl ions, was inferred. OH···O hydrogen bond lengths were calculated from the Raman and infrared spectra using Libowitzky's empirical relation. Small differences in the Raman spectra between both samples were observed and attributed to compositional and hydrogen-bonding network differences. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Treatment methods for the determination of ,2H and ,18O of hair keratin by continuous-flow isotope-ratio mass spectrometry

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 17 2005
Gabriel J. Bowen
The structural proteins that comprise ,90% of animal hair have the potential to record environmentally and physiologically determined variation in ,2H and ,18O values of body water. Broad, systematic, geospatial variation in stable hydrogen and oxygen isotopes of environmental water and the capacity for rapid, precise measurement via methods such as high-temperature conversion elemental analyzer/isotope ratio mass spectrometry (TC/EA-IRMS) make these isotope systems particularly well suited for applications requiring the geolocation of hair samples. In order for such applications to be successful, however, methods must exist for the accurate determination of hair ,2H and ,18O values reflecting the primary products of biosynthesis. Here, we present the results of experiments designed to examine two potential inaccuracies affecting ,2H and ,18O measurements of hair: the contribution of non-biologic hydrogen and oxygen to samples in the form of sorbed molecular water, and the exchange of hydroxyl-bound hydrogen between hair keratin and ambient water vapor. We show that rapid sorption of molecular water from the atmosphere can have a substantial effect on measured ,2H and ,18O values of hair (comprising ,7.7% of the measured isotopic signal for H and up to ,10.6% for O), but that this contribution can be effectively removed through vacuum-drying of samples for 6 days. Hydrogen exchange between hair keratin and ambient vapor is also rapid (reaching equilibrium within 3,4 days), with 9,16% of the total hydrogen available for exchange at room temperature. Based on the results of these experiments, we outline a recommended sample treatment procedure for routine measurement of ,2H and ,18O in mammal hair. Copyright © 2005 John Wiley & Sons, Ltd. [source]