Stable jets of viscoelastic fluids and self-assembled cylindrical capsules by hydrodynamic focusing

We demonstrate formation of long-lived cylindrical jets of a viscoelastic fluid using hydrodynamic focusing. A solution of polyacrylamide in water is driven coaxially with immiscible oil and subjected to strong extensional flow. At high flow rates, the aqueous phase forms jets that are 4-90 microm in diameter and several centimeters long. The liquid surfaces of these jets are then used as templates for assembly of microspheres into novel rigid and hollow cylinders.     

Calculation of the first nonlinear contribution to the general-relativistic spin-spin interaction for binary systems

We use recently developed effective field theory techniques to calculate the third order post-Newtonian correction to the spin-spin potential between two spinning objects. This correction represents the first contribution to the spin-spin interaction due to the nonlinear nature of general relativity and will play an important role in forthcoming gravity wave experiments.     

Die Existenz irreduzibler analytischer Flächen,welche sich über den Rand eines gegebenen Regularitätsbereiches nicht fortsetzen lassen

Ohne ZusammenfassungHerrn Prof. H.Kneser bin ich für wertvolle Ratschläge bei der Drucklegung der Arbeit dankbar.     

Die invariante Fassung des Kontinuitätssatzes für meromorphe Funktionen

Ohne Zusammenfassung     

Physics of selective systems: Computation and biology

The statistical thermodynamics of systems displaying selective behavior is used to discuss some important ultimate physical limitations of computers and biological systems. These cluster around communication of information, measurement, and irreversible processes. The most fundamental limitation is irreducible increase of entropy accompanying selective acts like measurement of preparation. Relevant theory of machines (automata. Turing machines) and issues involved in physical realizations of those machines are discussed. Quantum measurement, the Einstein-Podolsky-Rosen paradox, the fundamental importance of irreversibility, information and entropy, and their relation to Goedel's theorems on completeness and consistency of formal systems are analyzed. Irreversibility of measurement appears necessary to provide quantum mechanics with the incompleteness needed to avoid inconsistency. Motivation and justification of computer paradigms for fundamental modeling of biological systems is given.     

Loschmidt's and Zermelo's paradoxes do not exist

A strict operational (i.e., informational) analysis of the meaning of preparing a system to realize the paradoxes of Loschmidt or Zermelo is made. Where reversal or recurrence are operationally realizable, no contradiction with the irreversible nature of macroscopic operations occurs. Paradox results either from neglecting irreversible phenomena in the means for preparing a reversed state, or from confusing elements or ensembles, which are meaningful in microstate language but meaningless operationally, with preparable macrostates, whoserepresentation in microstate language is an ensemble whose very definition is incompatible with that of any paradox-generating element or ensemble,Supported in part by NSF Grant No. GN 534.1.     

Bemerkungen zur Theorie komplexer Räume

Ohne ZusammenfassungMeinem LehrerHeinrich Behnke zum 60. Geburtstag     

Water-mediated interactions in the CRP–cAMP–DNA complex: Does water mediate sequence-specific binding at the DNA primary-kink site?

The cyclic AMP receptor protein (CRP) of Escherichia coli binds preferentially to DNA sequences possessing a T:A base pair at position 6 (at which the DNA becomes kinked), but with which it does not form any direct interactions. It has been proposed that indirect readout is involved in CRP-DNA binding, in which specificity for this base pair is primarily related to sequence effects on the energetic susceptibility of the DNA to kink formation. In the current study, the possibility of contributions to indirect readout by water-mediated hydrogen bonding of CRP with the T:A base pair was investigated. A 1.0 ns molecular dynamics simulation of the CRP-cAMP-DNA complex in explicit solvent was performed, and assessed for water-mediated CRP-DNA hydrogen bonds; results were compared to several X-ray crystal structures of comparable complexes. While several water-mediated CRP-DNA hydrogen bonds were identified, none of these involved the T:A base pair at position 6. Therefore, the sequence specificity for this base pair is not likely enhanced by water-mediated hydrogen bonding with the CRP.     

Das Maximumprinzip und die Singularitäten analytischer Mengen

Ohne ZusammenfassungMeinem verehrten Lehrer Heinrich Behnke zum 70. Geburtstag