Outline of Synthesis of Cognitive and Socio-cultural Foundations of Scientific Knowledge Evolution in Research Programs of Western Philosophy of Science

The article analyses the development of cognitive sociology of science, in the object field of which connection of cognitive and social structures of science is traced. The role of context in scientific knowledge formation is defined. It is stated that the basis for development of research program of cognitive sociology of science appeared to be reconsideration of the standard concept of science as a complex of gnoseological, epistemological and methodological interpretations of nature and morphology of the produced scientific knowledge, methods for its explanation and scientificity ideals. The difference between "strong" and «weak» varieties of scientific knowledge evolution, developed in western philosophy of science, is considered. "Social studies of science" are reviewed as a form of social constructivism and relativism, exhibiting their specific nature in macro-analytical and micro- analytical strategies of scientific knowledge evolution analysis. The thesis that multidimensionality of science cannot be adequately interpreted focusing only on conceptual history of science is proved

EPR spectra of spin labels in lipid bilayers : II. Rotation of steroid spin probes

The spin label method is used to investigate the nature of molecular motion in a liquid crystalline bilayer. The EPR spectra of different spin labels are simulated by means of perturbation theory. Using the diffusion model with a restoring potential the rotational diffusion coefficients for the different spin labels are evaluated from the linewidth. Rotational diffusion and viscosity are related by a modified Stokes‐Einstein‐Perrin formula. The correction factors account for the difference between the effective viscosity during rotation and the (translational) viscosity and are interpreted in terms of the geometry and the ordering of the spin probes. The bilayer viscosity η is found to be 3.7 cp ≤ η ≤ 5.7 cp

EPR spectra of spin labels in lipid bilayers

Assuming a probability function P(θ)αexp{(−q/RT)cos2Θ} for the orientation of the chain segments in a lipid bilayer, a quantitative theory for the spin label spectra of such systems is developed. Only three parameters, namely two energy parameters q3 and q1 and the correlation time τ20 are required to yield perfect agreement between experimental and theoretical spectra for correlation times up to 3 × 10−9 sec. In calculating the EPR spectra pseudosecular and nonsecular contributions to the linewidth are included, since especially the former exert a distinct influence on the spectra. Also discussed are the effects of tilt angle and spread angle. The theory is applied to the anisotropic motion of the fatty acid spin label I (13.2) in a decanol‐sodium decanoate bilayer. Between 44 and 8°C the correlation time is found to increase exponentially from 1.0 × 10−10 to 4.0 × 10−10 sec with an activation energy of 6.84 kcal mole−1. The energy parameters q3 and q1, which determine the order parameters S3 and S1, remain constant in the same temperature range (q3 = −2.9 kcal mole−1; q1 = 1.7 kcal mole−1). The average orientation of the chain segment is perpendicular to the bilayer normal. Below 8°C a phase transition occurs and the chain segments become gradually tilted. At −8°C the correlation time has increased to 2.8 × 10−9 sec and the chains are now tilted by approximately 18° from the bilayer normal. From the correlation time the translational diffusion constant can also be deduced. At 21°C a value of Dtrans = 1.5 × 10−6 cm2 sec−1 is obtained for the lipid molecules in the decanol‐sodium decanoate bilayer. In vesicles of dimyristoyl‐L‐α‐lecithin at 21°C the analysis of the spectrum yields a correlation time of 2.5 × 10−9 sec and a diffusion constant of the lipid molecules of Dtrans = 3.6 × 10−8 cm2 sec−1

The acetylcholine receptor: double-channel, noncovalent interactions and a possible role for the [delta]-[delta]-disulfide bridge

Spillecke F, Schindler H, Neumann E. The acetylcholine receptor: double-channel, noncovalent interactions and a possible role for the [delta]-[delta]-disulfide bridge. Hoppe-Seyler's Zeitschrift für physiologische Chemie. 1983;364:1220

The dimer of torpedo acetylcholine receptor: synchronizd double channel

Neumann E, Spillecke F, Schindler H. The dimer of torpedo acetylcholine receptor: synchronizd double channel. In: Changeux J-P, ed. Molecular basis of nerve activity: proceedings of the Internat. Symposium in Memory of David Nachmansohn (1899 - 1983), Berlin (West), Germany, October 11 - 13, 1984. Berlin: de Gruyter; 1985: 369-385