Rapid measurement of cyclosporin a plasma levels by HPLC in allograft transplant recipients

Summary An HPLC-method for the measurement of blood Cyclosporin A levels (CyA) of renal allograft transplanted patients within 9min is described. After a simple protein precipitation of the blood the supernatant is transferred to an HPLC-system. The short time of analysis is obtained by a step gradient elution technique and a precolumn separation of the fractions of interest followed by a backflush regeneration step of the precolumn. The analysis of the fraction of interest takes place on a column with high resolution power as long as the precolumn is regenerated. CyA is monitored by UV-absorption at 206nm. Detection of 20 to 2000ng/ml CyA allows the use of the method for patient monitoring and for research purposes. Presented at the 15th International Symposium on Chromatography, Nürnberg, October 1984     

How far, how long: on the temporal scope of prosodic boundary effects

Acoustic lengthening at prosodic boundaries is well explored, and the articulatory bases for this lengthening are becoming better understood. However, the temporal scope of prosodic boundary effects has not been examined in the articulatory domain. The few acoustic studies examining the distribution of lengthening indicate that boundary effects extend from one to three syllables before the boundary, and that effects diminish as distance from the boundary increases. This diminishment is consistent with the pi-gesture model of prosodic influence [Byrd and Saltzman, J. Phonetics 31, 149-180 (2003)]. The present experiment tests the preboundary and postboundary scope of articulatory lengthening at an intonational phrase boundary. Movement-tracking data are used to evaluate durations of consonant closing and opening movements, acceleration durations, and consonant spatial magnitude. Results indicate that prosodic boundary effects exist locally near the phrase boundary in both directions, diminishing in magnitude more remotely for those subjects who exhibit extended effects. Small postboundary effects that are compensatory in direction are also observed.     

Small-Angle and Wide-Angle X-Ray Scattering Study of Slow Relaxation Following Phase Transitions of New Bolaamphiphiles Based on N-(12-Betainylamino-Dodecane)-octyl β-D-Glucofuranosiduronamide Chloride

In the present study, we investigated the polymorphism and its time-dependence of a new series of bolaamphiphile molecules based on N-(12-Betainylamino-dodecane)-octyl β-D-Glucofuranosiduronamide Chloride. To obtain six members of this series, the length of the main bridging chain and the lateral chain were varied in order to modify the hydrophilic–lipophilic balance. Another chemical modification was to introduce a diacetylenic unit in the middle of the bridging chain to study the influence of the π–π stacking on the supramolecular organization of these molecules. Dry bolaamphiphiles self-organize in supramolecular structures such as lamellar crystalline structure, L_c; lamellar gel structure, L_β′; lamellar fluid structure, L_α; and lamellar isotropic structure, L. Thermal hysteresis of these structures, following phase transitions, are investigated by small-angle and wide-angle X-ray scattering. Once the thermal cycle is accomplished, the system remains in the kinetically stabilized undercooled high-temperature phase at the temperature of 20°C. Subsequently, the time-dependence of the relaxation to the thermodynamically stable phase is followed, and very slow relaxation for a period on the order of hours or days is observed. The study of the polymorphism and the stability of various phases of this new series of bolaamphiphiles—which are issued from natural primary resources (sugar beet and wheat) and thus interesting for potential application in pharmaceutical, cosmetics, or food industry—was undertaken in this work.     

Compactness of operators acting from a Lorentz sequence space to an Orlicz sequence space

LetX andY be closed subspaces of the Lorentz sequence spaced(v, p) and the Orlicz sequence spacel _M , respectively. It is proved that every bounded linear operator fromX toY is compact whenever

Viscometric and volumetric behaviour of binary mixtures of sulfolane and N-methylpyrrolidone with monoethanolamine and diethanolamine in the range 303–373 K

Capillary viscometry was used to determine the kinematic viscosity of the binary systems composed of N-methylpyrrolidone + monoethanolamine and N-methylpyrrolidone + diethanolamine throughout the concentration range, at eight different temperatures in the range 303.15–373.15 K. Pure component values of viscosity were also determined in the temperature range 303.15–423.15 K. Using a rolling ball viscometer the absolute viscosity was obtained for the binary systems composed of tetramethylene sulfone (sulfolane) + monoethanolamine and tetramethylene sulfone + diethanolamine, throughout the concentration range, at three different temperatures in the range 303.15–373.15 K. Density results were obtained using a vibrating-tube densimeter for the four pure components and the four binary systems studied, in the same temperature range and the whole concentration range for the binary systems as the viscosity measurements.

The experimental viscosity results for the four pure solvents cover a broader temperature range than previously reported by other workers. The experimental results of viscosity for both pure and binary systems show a decrease with increasing temperature as expected. In the case of the binary systems the change of viscosity with concentration for the two sets of mixtures with N-methylpyrrolidone is very large in the range of 303.15–353.15 K, whereas it is small in the range 363.15–373.15 K. The observed behaviour of the change of viscosity with concentration for sulfolane with monoethanolamine is different from that shown by sulfolane with diethanolamine, at 303.15 and 323.15 K; the first system shows a minimum viscosity point in the sulfolane-rich region whereas at 373.15 K it shows values of viscosity greater than that of the pure components in the whole range of concentration; and the second system shows large variations of viscosity at low sulfolane concentration, at 303.15 and 323.15 K; whereas at 373.15 K the viscosity values change smoothly between those for the two pure components.

From the density results, molar excess volumes were derived, which were correlated using the Redlich–Kister equation; the final expression includes the functionality with both concentration and temperature.