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  • 1
    Electronic Resource
    Electronic Resource
    On the theory of adsorption kinetics of ionic surfactants at fluid interfaces (1985)
    Springer
    Colloid & polymer science 263 (1985), S. 420-423 
    Details
    ISSN: 1435-1536
    Keywords: adsorption kinetics ; ionic surfactants ; electric double layer influence ; theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The kinetic equation to describe the adsorption process of ionic surfactants (derived in part 1) will be solved numerically. The results show the effect of parameters such as ion valencyz, thickness of theDL x −1, and surfactant parametersΓeq,K, andK ads on the adsorption process. The results can be used to decide whether the model can explain experimental data on charged surfactant molecules or not.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01410392
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  • 2
    Electronic Resource
    Electronic Resource
    Determination of theophylline clearance in South African children (1993)
    Springer
    European journal of clinical pharmacology 44 (1993), S. 369-375 
    Details
    ISSN: 1432-1041
    Keywords: Theophylline ; children ; population pharmacokinetics ; Nonmem ; age ; gender ; race
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Theophylline clearance values in South African children were determined using 400 serum theophylline concentration measurements gathered from 109 compliant outpatients during their normal routine care. Population pharmacokinetic analysis was done using the Non-Linear Mixed Effects Model (Nonmem) to analyse the data. Nonmem was also used to estimate the influence of fixed effects (weight, age, race, gender etc) on clearance and its interindividual variability. Gender, age, and weight raised to an iterated exponent were found to be the most important demographic fixed effect parameters influencing clearance. Race was not found to be important. The weight-adjusted values of theophylline clearance decreased with increasing age. The actual values expressed in l·h−1·kg−1 were 0.0949 for children aged 1–5 y; 0.0813 for children aged 5–9 y, and 0.0660 for children of 9–16 y. The values are similar to those reported in other studies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00316475
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  • 3
    Electronic Resource
    Electronic Resource
    Ketotifen pharmacokinetics in children with atopic perennial asthma (1997)
    Springer
    European journal of clinical pharmacology 52 (1997), S. 383-386 
    Details
    ISSN: 1432-1041
    Keywords: Key words Ketotifen; pharmacokinetics ; children ; ␣clearance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objective: Published pharmacokinetic data on ketotifen are sparse, although it is a commonly used prophylactic agent in various allergic disorders in adults and children. The aim of this study was to assess the steady-state pharmacokinetics of ketotifen in children with atopic perennial asthma who were participating in a clinical trial. Method: The NONMEM population approach with sparse sampling was utilized. The data set consisted of 239 samples from 48 children who were randomized to receive either 1 mg or 2 mg oral ketotifen daily. Patients underwent a clinical examination and had a blood sample taken at 2-week intervals for 12 weeks. The ketotifen concentrations were measured by RIA. Results: A one-compartment model with first-order absorption was fit to the data. Volume was estimated at 394 l and clearance (CL) at 97.4 l · h−1 (3.6 l · h−1 · kg−1). Weight or body surface area were the most influential covariates for explaining interindividual variability in CL. The 2-mg dose appeared to have a relative bioavailability of 85% of the 1-mg dose. Conclusion: Children have a faster clearance of ketotifen than adults and would therefore require a higher dose per kilogram body weight to give comparable steady-state levels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050305
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  • 4
    Electronic Resource
    Electronic Resource
    Determination of phenobarbitone population clearance values for South African children (1995)
    Springer
    European journal of clinical pharmacology 48 (1995), S. 381-383 
    Details
    ISSN: 1432-1041
    Keywords: Phenobarbitone ; children ; population pharmacokinetics ; NONMEM ; concomitant medication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Non-linear Mixed Effects Modelling (NONMEM) was used to estimate phenobarbitone population clearance values for South African children, using 52 serum levels gathered from 32 patients during their routine care. NONMEM was also used to evaluate the influence of fixed effects such as weight, age and concomitant medication. The final model describing phenobarbitone clearance was CL=[Exp(0.0288 Wt−2.53)] M, where CL=clearance (l·h−1), Exp=the base of the natural logarithm, Wt=patient weight (kg) and M=a scaling factor for concomitant medication with a value of 1 for patients on phenobarbitone monotherapy, 0.62 for those receiving concomitant valproate and 0.87 for those patients receiving concomitant carbamazepine or phenytoin. Mean (95% confidence interval) phenobarbitone clearance values were 7.6 ml·h−1·kg−1 (6.2, 9.0 ml·h−1·kg−1) for the monotherapy group, 5.0 ml·h−1·kg−1 (4.0, 6.0 ml·h−1·kg−1) in the presence of concomitant valproate and 6.8 ml·h−1·kg−1 (5.6, 8.0 ml·h−1·kg−1) in the presence of concomitant carbamazepine or phenytoin. These values are similar to those previously reported from both traditional and NONMEM pharmacokinetic studies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00194954
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  • 5
    Electronic Resource
    Electronic Resource
    On the theory of adsorption kinetics of ionic surfactants at fluid interfaces 3. Generalization of the model (1991)
    Springer
    Colloid & polymer science 269 (1991), S. 923-928 
    Details
    ISSN: 1435-1536
    Keywords: Adsorptionkinetics ; theory ; ionicsurfactants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract It was shown that, in the case of adsorbing ions, the Boltzmann equation cannot be applied in its classical form, but has to be modified by considering the flux of adsorbing ions. From the comparison with the adsorption of nonionic surfactants a ratio results which is the measure of deceleration of adsorption kinetics due to the electric double layerr=K(y s)/δ(t). At highr-values the electrostatic deceleration controls the adsorption kinetics process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00657309
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  • 6
    Electronic Resource
    Electronic Resource
    On the theory of adsorption kinetics of ionic surfactants at fluid interfaces (1983)
    Springer
    Colloid & polymer science 261 (1983), S. 335-339 
    Details
    ISSN: 1435-1536
    Keywords: Adsorption kinetics ; ionic surfactants ; influence of the electric double layer ; theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The influence of the electric field caused by an electric double layer (DL) on the adsorption kinetics of charged surfactant molecules at fluid interfaces is described for the case of high surface potentials and a quasi-equilibrium state of the DL. Known relations for the description of the transport of molecules in the diffusion layer and the DL respectively are used.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01413940
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  • 7
    Electronic Resource
    Electronic Resource
    Adsorption kinetics of surfactants from micellar solutions (1981)
    Springer
    Colloid & polymer science 259 (1981), S. 1124-1128 
    Details
    ISSN: 1435-1536
    Keywords: Adsorption kinetics ; surfactants ; micellar solutions ; theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Zusammenfassung Es wird ein Modell für die diffusionskontrollierte Adsorption von Tensiden aus mizellaren Lösungen angegeben und numerisch gelöst. Das dabei zugrundegelegte Modell für die Mizellkinetik entspricht einem Bildungs-Auflösungs-Mechanismus. Es wird der Einfluß von Parametern wie Mizellkonzentration, Assoziationsgrad, Geschwindigkeitskonstanten der Mizellkinetik auf die Adsorptionskinetik diskutiert.
    Notes: Summary A model of diffusion controlled adsorption of surfactants from micellar solutions is given and numerically solved. The model used to describe the micelle kinetics corresponds to a formation-dissolution mechanism. Parameters like micelle concentration, aggregation number, rate constant of formation or dissolution of micelles influencing the adsorption process are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01524900
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  • 8
    Electronic Resource
    Electronic Resource
    Transmission electron microscopy of 3F/PMDA-polypropylene oxide triblock copolymer based nanofoams (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 35 (1997), S. 1067-1076 
    Details
    ISSN: 0887-6266
    Keywords: transmission electron microscopy ; block copolymer ; polyimide ; nanofoam ; porous films ; polymer foam ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Transmission electron microscopy was performed on a polymeric nanofoam material, derived from a triblock copolymer composed of a fluorinated polyimide center block, 3F/PMDA (derived from pyromelletic dianhydride (PMDA) and 1,1-bis(4-aminophenyl)-1-phenyl-2,2,2-trifluoroethane (3F)) and polypropylene oxide (PO) end blocks. The cast and imidized polymer exhibits a microphase-separated morphology consisting of PO microdomains within a polyimide matrix. The final nanofoam material is obtained by decomposing PO microdomains into low molecular weight products, which diffuse out of the polyimide matrix leaving nanometer length scale voids. Ruthenium tetroxide staining prior to microscopy was used to enhance the contrast between the 3F/PMDA matrix and the PO microdomains or voids, which permitted a more detailed view of the microstructure of both the foamed and unfoamed materials. From the power spectra of the micrographs, spatial correlation between the PO microdomains in the unfoamed material and between the voids in the foam were found. An interdomain separation distance of ca. 37 nm was observed. Analysis of the image yielded an average area of 411 nm2 for the PO domains. The analysis indicated that the PO domains were oblong, having average major and minor dimensions of 35 and 12.5 nm, respectively. An autocorrelation of the image showed that the domain center of masses were positioned 41 nm apart, in close agreement with the domain spacing (ca. 37 nm) found as described above. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 1067-1076, 1997
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Molecular probe techniques for studying diffusion and relaxation in thin and ultrathin polymer films (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 35 (1997), S. 2795-2802 
    Details
    ISSN: 0887-6266
    Keywords: ultrathin polymer films ; fluorescence nonradiative energy transfer ; second harmonic generation ; polymer relaxation ; small-molecule diffusion ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Two optically based, molecular probe techniques are employed to study relaxation and small-molecule translational diffusion in thin and ultrathin (thicknesses 〈 ∼200 nm) polymer films. Second harmonic generation (SHG) is used to study the reorientational dynamics of a nonlinear optical chromophore, Disperse Red 1 (DR1) (previously shown to be an effective probe of α-relaxation dynamics) either covalently attached or freely doped in polymer films. Our studies on films ranging in thickness from 7 nm to 1 μm show little change in Tg with film thickness; however, a substantial broadening of the relaxation distribution is observed as film thickness decreases below approximately 150 nm. Experimental guidelines are given for using fluorescence nonradiative energy transfer (NRET) to study translational diffusion in ultrathin polymer films. Appropriate choice of a fluorescence donor species is important along with ensuring that diffusion is slow enough to be measured appropriately. Initial results on the diffusion of a small-molecule probe, lophine, in poly(isobutyl methacrylate) indicates that there is little change in probe diffusion coefficients in films as thin as 90 nm as compared to bulk films. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 2795-2802, 1997
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Phase transfer-catalyzed nitromercuration of diene polymers (1980)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 2723-2729 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A mild, efficient method of nitrating olefins was described recently by Corey and Estreicher. Application of their procedure to diene polymers failed because of the insolubility of the hydrophobic polymer in the aqueous nitromercuration regent. Use of water-immiscible organic cosolvents gave slow nitromercuration with substantial formation of nitrite esters. To overcome these problems a nonaqueous phase transfer-assisted method of rapid selective nitromercuration of diene polymers was developed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1980.170180828
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