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  • Electronic Resource  (5)
  • Inorganic Chemistry  (2)
  • critical point  (2)
  • Acetylsalicylic acid (ASA)  (1)
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  • Electronic Resource  (5)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Archives of gynecology and obstetrics 233 (1982), S. 15-22 
    ISSN: 1432-0711
    Keywords: Tocolytic treatment ; Acetylsalicylic acid (ASA) ; Pharmacokinetics in pregnancy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Pregnant women were treated with infusions of acetylsalicylic acid (ASA). The plasma concentrations of total salicylate or those of ASA and salicylic acid (SA) were determined. The ASA steady state was reached after 2 h of infusion whereas 3 days seemed necessary to reach the steady state of SA. In a further study during the late phase of cervical dilatation (12 min – 2 h before birth) healthy pregnant women were given 1 g ASA as a single i.v. bolus injection. The resulting plasma levels of ASA and SA in the mothers during delivery, the plasma concentrations in umbilical cord blood and in blood obtained from the newborn several hours after birth were measured. With increasing time the SA concentrations in the umbilical cord blood plasma approached those of the mothers. On the other hand, the umbilical cord blood concentrations of ASA did not approach the maternal concentrations, probably because of the ASA esterase activity at the placental barrier. The plasma concentrations in the newborn indicated that the newborn is able to degrade ASA and to excrete SA. However, the velocities are lower than the respective velocities in adults.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    International journal of thermophysics 19 (1998), S. 481-490 
    ISSN: 1572-9567
    Keywords: critical point ; temperature control ; temperature gradients ; thermostat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The density of a pure fluid near its critical point is extremely sensitive to temperature gradients. In the absence of gravity, this effect limits the fluid's homogeneity. For example, at 0.6 mK above the critical temperature, the microgravity experiment Critical Viscosity of Xenon (CVX) can allow temperature differences no larger than 0.2 μK, corresponding to a gradient of 10−5 K·m−1. The CVX thermostat, which consists of a thick-walled copper cell contained within three concentric aluminum shells, was designed to achieve such a small temperature gradient. However, asymmetries not included in the thermostat's model could degrade the thermostat's performance. Therefore we measured the temperature gradient directly with a miniature commercial thermoelectric cooler consisting of 66 semiconductor thermocouples. We checked the results with a half-bridge consisting of two matched thermistors. The measurement was made along a thin-walled stainless-steel cell whose conductance was much lower than that of the copper cell, thus “amplifying” the temperature differences by a factor of 60. When the thermostat was controlled at a constant temperature, the steel cell's static temperature difference was 5±1 μK. (The value inferred for the copper cell is 0.08 μK.) Ramping the thermostat's temperature at a rate of 1 × 10−5 K·s−1 increased the temperature difference to 0.36 mK. These results demonstrate the feasibility of achieving extremely low temperature gradients.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    International journal of thermophysics 7 (1986), S. 675-686 
    ISSN: 1572-9567
    Keywords: critical point ; cyclohexane ; methanol ; torsion oscillator ; viscometer ; viscosity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A torsion-oscillator viscometer has been constructed for the measurement of the viscosity of fluids near both liquid-vapor and liquid-liquid critical points. This viscometer has a resolution of ±0.2% and operates at a low frequency (0.6 Hz) and a very low shear rate (0.05 Hz). Thus, it can be used closer to critical points than other viscometers before encountering the non-Newtonian phenomena associated with critical slowing down. This viscometer was used to study the viscosity anomaly near the consolute point of mixtures of methanol and cyclohexane along paths of constant pressure and paths of constant volume at temperatures spanning the range 10−5 〈 (T-T c)/T c〈10−2. The data are consistent with a simple, power-law divergence of the viscosity with a multiplicative background characterized by an apparent exponent y≈0.041. Recent theoretical estimates for y are near 0.033. If the data are to be fit with the theoretical value of y, one must simultaneously restrict the range of the data and introduce additional unphysical parameters into the fitting function.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 189 (1930), S. 101-112 
    ISSN: 0863-1786
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1. Es wird die Eignung der selenigen Säure für analytische Zwecke gezeigt und.
    Additional Material: 12 Tab.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Über die Bildung von [Na(POCl3)4]+-Komplexionen. Leitfähigkeits-, Raman- und NMR-Untersuchungen im System Phosphorylchlorid-Natriumtetrachloroaluminat bzw. analoger VerbindungenLeitfähigkeiten, Raman- sowie 27Al-, 23Na- und 31P-NMR-Spektren des Systems POCl3-NaAlCl4 wurden in Abhängigkeit vom Molenbruch x(NaAlCl4) im lösungsmittelreichen Gebiet gemessen. Zusätzlich erfolgte die Registrierung der Raman-Spektren der Lösungen von NaFeCl4, LiAlCl4, LiFeCl4 und KAlCl4 in POCl3. In den Li+- bzw. Na+-Ionen enthaltenden Proben konnte unter bestimmten Bedingungen ein von Temperatur und Salzkonzentration abhängiger Phasenübergang von der flüssigen in die feste Phase beobachtet werden. Deutliche Veränderungen in den Ramanspektren der Elektrolytlösungen im Vergleich zum reinen Lösungsmittel POCl3 belegen die Existenz von intermolekularen Wechselwirkungen, durch die das POCl3-Molekül beeinflußt wird. Die Annahme der Bildung von [M(POCl3)4]+-Solvaten (M = Li, Na) aufgrund der Ramanergebnisse wird durch die Resultate der NMR-Spektroskopie unterstützt.
    Notes: The system POCl3-NaAlCl4 was investigated by measuring the conductivity and the Raman and NMR spectra (27Al, 23Na and 31P) as a function of the mol fraction x of NaAlCl4 in POCl3. Additionally, Raman spectra of POCl3 solutions of NaFeCl4, LiAlCl4, LiFeCl4, and KAlCl4 were recorded. In solutions containing Li+ or Na+ ions a liquid to solid (or jelly) phase transition was observed under certain conditions, dependent on salt concentration and temperature. Observed changes in the Raman spectra of the electrolyte solutions in comparison to the pure solvent POCl3 demonstrate the existence of interactions. Clearly, the POCl3 eigenfrequencies and hence the molecules are pertubed. The formation of [M(POCl3)4]+ complexes (M = Li, Na) can be deduced from the Raman measurements. NMR investigations support this conclusion. For assigning of Raman spectra, (Li+, K+) cation and ([FeCl4]-, [SbCl6]-) anion substitutions were employed.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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