Counterion condensation as saturation effect under the influence of ion hydration.

Polyelectrolyte solutions are often described by structural theories. These theories in some cases yield values for the counterion concentration at the charged monomer surface that exceed the saturation concentration. This means a change of the ion properties due to ion immobilization or ion condensation in close vicinity to the polymer chain. The extent of this counterion condensation (CIC) and the respective surface potential are calculated from the saturation concentrations of the electrolyte involved including the influence of ion hydration on the effective dielectric number. In this paper, we shall consider all these influences by a fundamental differential equation and a set of explicit formulae yielding quantitative expressions without linearization. All calculations are based on the abstraction of an idealized elementary cell.

Network of characterizing functions for stationary populations.

A variety of open systems in nature and society exist under dynamic equilibrium, maintained by statistical counterbalance between the entering and leaving of individuals and the stationarity of the exchange processes. A network of functions characterizing the dynamics of such a stationary population is established and discussed, which allows the mutual transference of system properties without the need of any explicit information about the microdynamic processes. In order to illustrate the potential benefit of these interdependence relations, examples taken from diverse branches of research (adsorption and reaction kinetics, demographic analysis, and coronary blood flow diagnosis) are given.

[Minimal model for representing the central and peripheral pulse based on the pulse wave theory]. / Minimalmodell zur Darstellung zentraler und peripherer Pulse auf der Basis der Pulswellentheorie.

The present paper discusses an optimized model for describing central and peripheral pulse waves. On the basis of these computer-aided calculations, further haemodynamic data may be evaluated with the aim of improving the possibilities of clinically invasive diagnostic evaluation of cardiovascular diseases.

Development of the rabbit retina. IV. Tissue tensility and elasticity in dependence on topographic specializations.

A method is introduced for the quantification of specific compliance and the elasticity of small pieces of living retinal tissue. These pieces are fixed at their margins by means of tissue glue, and loaded with a small iron spherule the bending force of which can be gradually enhanced by the action of an electromagnet. Retinal bending caused by such calibrated forces is measured by a horizontal light microscope, and used for estimations of specific compliance and elasticity of the tissue. Three different particular regions of the rabbit retina--periphery, visual streak, and (prospective) medullary rays--were tested at several post-natal developmental stages. From very early stages on (day 2 p.p.) up to adulthood the peripheral retina was found to be significantly more tensile than the two other central regions. This can be shown to depend greatly on the thickness of the tissue which is lower in the retinal periphery. During early post-natal development, all retinal regions except the (prospective) medullary rays become thinner. The tensility of the tissue increases, with the exception of the medullary rays which reduce their compliance strongly. In the adult retina, however, the tensility of all retinal regions is reduced as compared with the neonatal tissue. This seems to be caused by a constant gradual increase of the elasticity of the retina during development which, in turn, may be caused by several developmental parameters, e.g. the formation of synapses, the outgrowth of glial side branches ensheathing neighbouring neuronal cells, or a reduction in extracellular clefts. It is proposed that these differences in tensility between different retinal regions, may be the cause for differential retinal expansion driven by the intraocular pressure. Thus, simple mechanical features of the tissue may contribute to the formation of important topographic specializations of the retina, e.g. the visual streak as the site of highest visual acuity.

[Tracer kinetic studies of the cholesterol metabolism in patients with hypercholesterolemia]. / Tracerkinetische Untersuchungen des Cholesterolstoffwechsels bei Patienten mit Hypercholesterolämie.

For the examination of the cholesterol metabolism in patients with normal and increased serum cholesterol the 3H-cholesterol was used. The tracer-kinetic investigation programme consisted of the examination of the serum for free and esterified cholesterol as well as the separation in VLDL-, LDL- AND HDL-fractions. The establishment of the content of radioactivity of the individual samples was carried out in the LSC-nitrobeta 1210. Specific activity-time-curves were established and fitted according to a mathematical programme. The most essential findings of the evaluation of these curves resulted in a clearly changed turnover of the LDL-fraction. Possible causes for the disturbed LDL-turnover were discussed.

[Macronucleolar transformation of a leukemic lymphosarcoma. Clinical morphologic and molecular biologic parameters]. / Makronukleolare Transformation eines leukämischen Lymphosarkoms. Klinische, morphologische und molekularbiologische Parameter

In a case with leukemic lymphosarcomatosis huge nucleoli developed at a final stage refractory to chemotherapy. The lymphosarcoma cells were characterized before and after their macronucleolar transformation by cell fractionation and by biochemical characterization of their nuclear 45S RNA fraction after high specific labelling with 32P-orthophosphate. The analyses provided evidence for a marked increase in nucleolar 45S RNA production. Processing of preribosomal RNA did not seem to be blocked. The biochemical alterations are discussed especially with respect to a possible significance of biological changes during the development of drug resistance against cytostatic agents.