Tracer studies on f-actin fluctuations

We present a study on the fluctuations of semiflexible actin filaments using fluorescence videomicroscopy, focusing on the end-to-end fluctuations of single filaments. In order to specifically measure the position of the polymer's ends, we developed a novel noninvasive method that consists of annealing short end tags to the filaments. This allows us to probe polymer fluctuations to a very high accuracy. We compared the distribution of the end-to-end distance with recent theoretical results, and found excellent agreement. We also studied the dynamics of the mean-square end-to-end distance deltaR2(t) and orientation of the ends, deltaTheta(2)(t), finding power laws t(3/4) and t(1/4), respectively. Scaling behavior for deltaR2(t) is observed over several decades in relaxation time in agreement with theoretical results.     

Black hole uniqueness from a hidden symmetry of Einstein's gravity

A theorem is proven that the only possible exterior solution for a pseudostationary, rotating, electrovacuum black hole with nondegenerate event horizon is the Kerr-Newman solution withM ²-J²/M²-Q²>0. A special role played in the proof of this theorem by the hidden symmetry groupSU(1, 2) of Einstein's equations is established.This essay received the third award from the Gravity Research Foundation for the year 1983 [Ed.].     

Multi-conjugate solar adaptive optics at the Vacuum Tower Telescope on Tenerife

We present a breadboard multi-conjugate adaptive optics (MCAO) system for high angular resolution solar observations which we operate at the Vacuum Tower Telescope. We have developed methods to estimate quantitatively the performance of solar adaptive optics from science data. Several sets of short exposure images of the solar photosphere were analyzed to assess the performance of the MCAO. We demonstrate that a 30 arcsec field of view is substantially improved when the MCAO system is turned on. This compares favourably with an improvement of a 10 arcsec field with conventional solar adaptive optics. We also show how irradiance fluctuations in the MCAO compensated focus can be suppressed. To cite this article: O. von der Lühe et al., C. R. Physique 6 (2005).     

Thermoplasma polariton within scaling theory of single-layer graphene

The electrodynamics of single-layer graphene is studied in the scaling regime. At any finite temperature, there is a weakly damped collective thermoplasma polariton mode whose dispersion and wavelength-dependent damping is determined analytically. The electric and magnetic fields associated with this mode decay exponentially in the direction perpendicular to the graphene layer, but, unlike the surface plasma polariton modes of metals, the decay length and the mode frequency are strongly temperature-dependent. This may lead to new ways of generation and manipulation of these modes.     

Über die Darstellung und die Eigenschaften des Indo-oxins

Zusammenfassung Es wird eine Darstellungsmethode für das vonBerg undBecker beschriebene Indo-oxin angegeben. Für das Produkt werden die Absorptionsspektren in verschiedenen Lösungsmitteln mitgeteilt. Die Darstellung des bisher unbekannten Hydrochlorids wird beschrieben.Mit 2 Abbildungen.Meinem verehrten Lehrer, Herrn Professor Dr.A. Franke, zum 80. Geburtstag gewidmet.W. P.     

Band structure of even and ions of odd polyenes

The analysis of experimental data for singlet transitions (E _n) of even polyenes (I), cations (II) and anions (III) of odd polyenes show that for infinite chains E (I)/E (II)=E (I)/E (III) = 2:1. It is shown that the energy gap is equal for the three systems. In cases (II) and (III) there is a level (NBMO) in the gap which is vacant in (II) and occupied in (III). That is why the first optical transition in (II) and (III) depends on the semiwidth of the gap.     

Der Nachweis des Eisens als Tri-n-butylammonium-eisen(III)-rhodanid

Ohne ZusammenfassungHierüber und über die quantitative Bestimmung des Eisens wird in Kürze berichtet.     

Über den Nachweis von Palladium mit Violursäure

Zusammenfassung Eine Fällungsreaktion von Palladiumsalz mit Violursäure in saurer Lösung wird als Nachweismöglichkeit für das Element neben Platin, Rhodium und Gold herangezogen. Die Untersuchung der Palladiumverbindung zeigt, daß das Metall mit zwei Violursäureresten verknüpft ist.

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Summary A precipitation reaction of palladium salt with violuric acid in acid solution is used to detect this element in the presence of platinum, rhodium, and gold. The study of the palladium compound showed that the metal is bound to two violuric acid radicals.

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Résumé Mise en évidence de la possibilité d'identifier le palladium en solution acide, en présence de platine, de rhodium et d'or par une réaction de précipitation du sel de palladium par l'acide violurique. L'étude de la combinaison palladiée montre que le métal est lié à deux restes violuriques.