Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1995-1999  (2)
  • Hydrodynamic  (1)
  • Pyruvate
  • Amino acid transport
  • 1
    Electronic Resource
    Electronic Resource
    Characterization of fluorescent surfactant aggregates by fluorimetric and viscosimetric techniques (1997)
    Springer
    Monatshefte für Chemie 128 (1997), S. 585-592 
    Details
    ISSN: 1434-4475
    Keywords: Fluorescence ; Hydrodynamic ; Micelle ; Surfactant ; Viscosity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Verbindung N,N-Dimethyl-N-2-(4-(t-butylphenoxy)ethoxy)ethyl-N-hexadecylammoniumchlorid (BDHC), eine oberflächenaktive Substanz mit zwei unterschiedlichen Seitenketten, wurde mittels einer Kombination von fluorimetrischen und viskosimetrischen Methoden charakterisiert. Anregung bei 274 nm ruft eine Fluoreszenz bei 315 nm hervor; diese Eigenschaft wurde zur Bestimmung der kritischen Micellenkonzentration (CMC) herangezogen. Es wurde ein geringfügig temperaturabhängiger Wert von 3.98×10−5 M gefunden (T min=25.35°C). Quenchexperimente mit 4-Nitroanilin ergaben eine Aggregationszahl von 42.0, viskosimetrische Untersuchungen einen hydrodynamischen Radius von 21.91 Å. Die erhaltenen Daten erlauben zusammen mit den Beziehungen nachTanford undEinstein-Stokes die Bestimmung der Micellenstruktur (sphärisch) und des Diffusionskoeffizienten (0.97×10−6 cm2/s). Das ΔG der Micellenbildung fürBDHC beträgt −34.9 kJ/mol.
    Notes: Summary A combination of fluorimetric and viscosimetric methods was used to characterize N,N-dimethyl-N-2-(4-(t-butylphenoxy)ethoxy)ethyl-N-hexadecylammonium chloride (BDHC), a doubletailed surfactant with dissimilar tail groups.BDHC was observed to fluoresce at 315 nm when excited at 274 nm, a feature which could be utilized to determine its critical micelle concentration (CMC). A value of 3.98×10−5 M was obtained and was observed to be slightly temperature dependent with aT min of 25.35°C. Fluorescence quenching experiments using 4-nitroaniline as a quencher were performed in order to determine the aggregation number which was found to be 42.0. The hydrodynamic radius of 21.91 Å was obtained using data from viscosimetric experiments. These data, together with theTanford andEinstein-Stokes relationships, were used to determine the micellar structure (spherical) and the diffusion coefficient (D=0.97×10−6 cm2/s), respectively. The ΔG of micellization forBDHC was determined to be −34.9 kJ/mol.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00807588
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Markers of cellular dysoxia during orthotopic liver transplantation in pigs (1998)
    Springer
    Intensive care medicine 24 (1998), S. 268-275 
    Details
    ISSN: 1432-1238
    Keywords: Key words Swine ; Liver transplantation ; Oxygen consumption ; Gastric tonometry ; Lactate ; Pyruvate ; Ketone bodies ; Carnitine ; Free fatty acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objective: To characterize global, regional, and end-organ markers of cellular dysoxia during orthotopic liver transplantation and early reperfusion in pigs. Design: Descriptive study. Setting: University hospital research laboratory. Animals and interventions: 7 fasted, anesthetized, and mechanically ventilated Yorkshire pigs underwent orthotopic liver transplantation. Oxygen consumption (VO2) and oxygen delivery (DO2) were both calculated using standard formulae. Gastric interstitial pH and the gastroarterial partial pressure of carbondioxide (PCO2) gradient were measured with a gastric tonometer. The following were determined from arterial blood samples: serum lactate to pyruvate ratio, serum 3-hydroxybutyrate to acetoacetate ratio, plasma free fatty acids, and plasma free and total carnitine levels. Measurements and results: Data were collected 1 h after induction of anesthesia (I), at the end of the anhepatic phase (A), and 1 h after reperfusion (R). Median (range) VO2 values obtained at the specified time points were: I 318 (206–1860), A 210 (152–408), R 330 (214–424) ml/kg per min, respectively (NS); DO2 values were: I 1828 (1382–3259), A 1219 (452–2492), R 1741 (1345–12 071) ml/kg per min, respectively (NS). The lactate to pyruvate ratio, reflecting the redox potential of the cytosol, progressively increased: I 22 (9–46), A 29 (16–68), R 43 (23–55) (P〈 0.05). Gastric interstitial pH, as well as the gastroarterial PCO2 gradient values at the specified time points did not reach statistical significance. Levels of ketone bodies (3-hydroxybutyrate+acetoacetate) remained lower than 0.120 mmol/l. The ketone body ratio did not significantly vary over time (NS). Plasma esterified and free carnitine concentrations and free fatty acid values remained within normal limits (NS). Among these markers, the ketone body ratio presented the largest area under the receiver operating characteristic curve as a marker of postoperative mortality, with an inflexion point at 0.9. Conclusions: In this study, orthotopic liver transplantation was associated with significant variations over time in the redox potential of the cytosol. Postoperative mortality was, however, related to the redox state of the liver mitochondria. Our data suggest the occurrence of abnormal tissue oxygenation during liver transplantation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001340050564
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...