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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 273 (1995), S. 83-95 
    ISSN: 1435-1536
    Keywords: Aggregation numbers ; ethyl hydroxyethyl cellulose ; sodium dodecyl sulphate ; interaction ; fluorescence quenching ; dye solubilization
    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 present investigation proves that in the interaction between an uncharged polymer and a negatively charged amphiphilic ion (surfactant) clusters are actually formed and it provides data for the cluster concentration and the cluster size and their variation with composition. The polymer bound cluster size increases after a certain critical surfactant concentration and passes through a maximum. This maximum cluster size decreases with decreasing polymer concentration and attains a limiting value at infinite dilution. For the highest polymer concentration the cluster size is close to the size of normal surfactant micelles. The cluster concentration was determined by a fluorescence quenching technique and the amount surfactant adsorbed to the polymer by dialysis equilibrium measurements. Combining these independent sets of data permits the cluster aggregation number to be unambiguously determined. Solubilization experiments indicate the possibility to regulate the amount solubilized by varying the polymer concentration. The molecular properties of the system are sensitively monitored by the variation in two vibronic peaks in the pyrene fluorescence emission spectrum which defines a “hydrophobic index”. Very good agreement is found between all three experimental methods. Finally, the model suggested is analyzed in terms of coil size and cluster-cluster distance. Depending upon the degree of adsorption saturation and the density of polymer segments in solution the interaction may switch from being intramolecular to becoming intermolecular.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 272 (1994), S. 338-347 
    ISSN: 1435-1536
    Keywords: Time dependence ; viscosity ; ethyl hydroxyethyl cellulose ; sodium dodecyl sulphate ; overlap concentration
    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 properties of the system EHEC/SDS/water in solution show considerable time dependence during several hours after preparation. The paper discusses various reasons for this time dependence. Similar time dependence in polymer solutions has been observed elsewhere. It is found that although the system properties vary, a true equilibrium is finally attained for all compositions. The most pronounced time dependence is shown in a region close to and above the CMC of a pure surfactant solution and for polymer concentrations at least equal to the critical overlap concentration. It is proposed that part of the explanation resides in the fact that in the solution preparation there appears intermediate states corresponding to high local polymer concentrations. Some quantitative aspects of the time dependence are also discussed.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 275 (1997), S. 830-840 
    ISSN: 1435-1536
    Keywords: Key words Ethyl hydroxyethyl cellulose ; sodium dodecyl sulfate ; interaction ; sodium chloride ; microviscosity ; average aggregation number ; micropolarity
    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 effect of small amounts of salt on the interaction between two fractions of ethyl(hydroxy)ethyl cellulose, EHEC, and sodium dodecyl sulfate, SDS, has been investigated by means of steady-state fluorescence measurements. The two polymer fractions display different properties in hydrophobicity expressed as different cloud points. The results are discussed in relation to hydrodynamic (viscosity) and thermodynamic (equilibrium dialysis) properties. The micropolarity as sensed by the probe pyrene shows that the polymers begin to interact with SDS at a lower concentration in the presence of salt. The average aggregation numbers of polymer-bound clusters, N p, were obtained by fluorescence-quenching data in combination with equilibrium dialysis experiments. N p was found to increase in the presence of salt for the EHEC fraction with a high cloud point (CP). The polymer with a low CP displays higher N p in the presence of salt at low SDS concentrations, but exhibit lower N p at higher SDS concentrations than in the salt-free system. The microviscosity index as determined by intramolecular excimer formation of 1, 3-di(1-pyrenyl)propane (P3P) is highest for the lowest N p and there is a corre-lation with N p in the presence as well as absence of salt for both EHEC fractions. It is found that when the same fractional amount of SDS is bound to the polymers, 10–20% of the value of saturation, the increase in macroviscosity occurs and the microviscosity shows high rigidity.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 274 (1996), S. 836-847 
    ISSN: 1435-1536
    Keywords: Ethyl hydroxyethyl cellulose ; sodium dodecyl sulphate ; interaction ; sodium chloride ; viscosity ; equilibrium dialysis
    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 Two fractions of ethyl(hydroxy)ethyl cellulose, EHEC, and their interactions with sodium dodecyl sulphate, SDS, have been investigated. The effect of salt on these interactions was explored. The more hydrophobic fraction exhibits a cloud point (CP) of 30°C, and the more hydrophilic fraction has a CP around 65°C. The properties of the systems were studied by means of hydrodynamic (viscosity), equilibrium dialysis and cloud point measurements. Dye solubilization was used to obtain indications of cluster formation on the polymer backbone. The equilibrium dialysis shows a steep binding beginning at a critical surfactant concentration indicating a cooperative effect in the EHEC/SDS/water system. It is found that when the degree of binding is moderate and only 10–20% of the value at saturation, the specific viscosity effects occur and solutions containing high polymer concentrations pass a marked maximum in viscosity. It is shown that the maximum in viscosity and the collcoil interaction, expressed as Huggins constant,k H, appear a composition with the same fractional amount of SDS adsorbed to both EHEC fractions. It was found that the onset of redistribution and increase in viscosity were shifted to higher SDS concentrations, although still below the normal CMC, for the EHEC fraction with a high CP. When small amounts of salt are present in the EHEC/SDS/water solutions, the CP curves develop a pronounced minimum at low SDS concentrations. The redistribution of SDS to the polymers starts immediately in the presence of salt, but the viscosity of the solutions is affected only in a very narrow composition interval.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Quality of life research 5 (1996), S. 532-538 
    ISSN: 1573-2649
    Keywords: Assessment ; children ; measure ; pre-adolescent ; quality of life
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Although interest in the health-related quality of life (HRQOL) of children has increased in the last years, validated methods for assessing the HRQOL-and especially the perceived HRQOL—of children have been missing. We introduced a 17-dimensional, illustrated, generic measure of perceived HRQOL (17D) for pre-adolescents, and demonstrated its application to three populations of children aged 8–11 years: (1) 244 normal schoolchildren; (2) 22 patients surviving organ transplantation and (3) 10 patients with genetic skeletal dysplasias. The HRQOL scores and profiles of the patients differed significantly according to the diagnosis, giving support to its construct validity. The reliability of the measure was high: its repeatability coefficient was 95%. As a structured interview of 20–30 minutes, the measurement burden is reasonable. We conclude that the assessment of quality of life of pre-adolescents can and should be based on data collected from the children themselves. Our initial experience indicates that 17D is comprehensive, reliable, and valid.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Quality of life research 5 (1996), S. 205-211 
    ISSN: 1573-2649
    Keywords: Adolescents ; children ; measure ; quality of life ; self-assessment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract While data on the health-related quality of life (HRQOL) of adults are accumulating, very little is known about the HRQOL—and especially the perceived HRQOL—of children. In our study we introduced a 16-dimensional, generic self-assessment measure of HRQOL (16D) for early adolescents, and demonstrated its use with four populations of children aged 12–15: (1) 239 normal schoolchildren, (2) patients waiting for organ transplantation (n=5), (3) patients with genetic skeletal dysplasias (n=19), and (4) patients with epilepsy (n=32). The HRQOL profiles of the patients differed significantly according to the diagnosis, giving support to its construct validity. The reliability of the measure was high: its repeatability coefficient was 91%. The quality of life ratings of the healthy boys and their parents differed on the dimensions of distress, vitality, speech, mental function, and discomfort and symptoms (p〈0.05). In addition, there were significant differences in the health-related valuations between the girls, boys and their parents. We conclude that the assessment of quality of life of adolescents should be based on data collected from the adolescents themselves. Further, the 16D is so far the only generic HRQOL measure designed specifically for this purpose. It is capable of differentiating the HRQOL of healthy adolescents as well as patients with various diagnoses. Our experience also indicates that it is easy to use, yet it seems comprehensive, reliable, and valid.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 428 (1996), S. 333-346 
    ISSN: 1432-2307
    Keywords: Congenital nephrotic syndrome ; Proteinuria ; Integrins ; Glomerular extracellular matrix
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The aim of this study was to examine the distribution of β1 and αv integrins (Ints) and some of their ligands in the kidneys of patients with congenital nephrotic syndrome of the Finnish type (CNF) and in controls using indirect immunofluorescence with monoclonal antibodies. The mesangial reactivity of Int α1 and Int β1 subunits was more variable and an increased glomerular reactivity with Int α3 and Int-α6 antibodies was found in CNF kidneys than in controls. Int α2 subunit was either completely missing from or found in significantly lesser amounts in CNF kidney glomeruli. The immunoreactivity for Int αv was more variable, fainter and also more granular in CNF samples than in control kidneys. The glomerular reactivity for Int β5 was more diffuse and weaker, and in sclerotic Bowman's capsules more intense in CNF kidneys than in controls. Immunoreactivity for Int β6 was restricted and was comparable in extent in CNF and control kidneys. Of the extracellular matrix components studied, the expression of EDAFn, EDBFn, OncFn, Ln α2 chain, Ln β1 chain and tenascin was increased. This is also seen in several glomerular diseases with inflammation and sclerosis. Immunoreactivity for vitronectin was decreased. Several differences were found in the intensity or location of the immunostaining for the β1 and αv Ints and their ligands in CNF kidneys compared with controls, which have not been found in any other proteinuric disease. Disturbed Int expression pattern in CNF may specifically reflect the disturbance of glomerular function caused by the primary defect in this disease.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Transplant international 11 (1998), S. S39 
    ISSN: 1432-2277
    Keywords: Key words Kidney transplantation ; Small children ; Graft survival ; Function ; Histopathology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Survival rates, renal function, and histopathology were evaluated in 49 prospectively followed patients transplanted under 5 years of age at our center. Most patients (84 %) suffered from congenital nephrosis of the Finnish type. Triple immunosuppression with cyclosporine administered in three daily doses to pre-school children was used. Patient survival 7 years after transplantation was 98 % and graft survival 88 %. All graft losses were due to post-transplantation nephrosis. The proportion of pathological findings in the follow-up biopsies did not change substantially with time. Five years after transplantation, 47 % showed a normal histology and after 7 years this rose to 67 %. Mean glomerular filtration rate (GFR) was 68 and 55 ml min per 1.73 m2 5 years and 7 years, respectively, after transplantation. The decline in GFR with time was significant. We conclude that good long-term results can be achieved with individually tailored triple immunosuppression in the youngest age group, even with cadaveric donors.
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