Existence of Local Covariant Time Ordered Products of Quantum Fields in Curved Spacetime

 We establish the existence of local, covariant time ordered products of local Wick polynomials for a free scalar field in curved spacetime. Our time ordered products satisfy all of the hypotheses of our previous uniqueness theorem, so our construction essentially completes the analysis of the existence, uniqueness, and renormalizability of the perturbative expansion for nonlinear quantum field theories in curved spacetime. As a byproduct of our analysis, we derive a scaling expansion of the time ordered products about the total diagonal that expresses them as a sum of products of polynomials in the curvature times Lorentz invariant distributions, plus a remainder term of arbitrarily low scaling degree. Received: 6 December 2001 / Accepted: 10 June 2002 Published online: 21 October 2002     

Protein adhesion on dental surfaces—a combined surface analytical approach

Protein adsorption is a field of huge interest in a number of application fields. Information on protein adhesion is accessible by a variety of methods. However, the results obtained are significantly influenced by the applied technique. The objective of this work was to understand the role of adhesion forces (obtained by scanning force spectroscopy, SFS) in the process of protein adsorption and desorption. In SFS, the protein is forced to and retracted from the surface, even under unfavorable conditions, in contrast to the natural situation. Furthermore, adhesion forces are correlated with adhesion energies, neglecting the entropic part in the Gibbs enthalpy. In this context, dynamic contact angle (DCA) measurements were performed to identify the potential of this method to complement SFS data. In DCA measurements, the protein diffuses voluntarily to the surface and information on surface coverage and reversibility of adsorption is obtained, including entropic effects (conformational changes and hydrophobic effect). It could be shown that the surface coverage (by DCA) of bovine serum albumin on dental materials correlates well with the adhesion forces (by SFS) if no hydrophobic surface is involved. On those, the entropic hydrophobic effect plays a major role. As a second task, the reversibility of the protein adsorption, i.e., the voluntary desorption as studied by DCA, was compared to the adhesion forces. Here, a correlation between low adhesion forces and good reversibility could be found as long as no covalent bonds were involved. The comparative study of DCA and SFS, thus, leads to a more detailed picture of the complete adsorption/desorption cycle.     

Aktivierungsanalytische Spurenbestimmung von Magnesium und Mangan in biologischer Matrix

Zusammenfassung Die Bestimmung kleinster Magnesium und Manganmengen nebeneinander, wie sie häufig etwa in biologischem Material erforderlich ist, bereitet bislang Schwierigkeiten. Aktivierungsanalytische Untersuchungen durch Bestrahlung mit thermischen Neutronen haben sogar zu Verwechslungen Anlaß gegeben, die sich durch die kurze Halbwertzeit des²⁷Mg im Verein mit der geringen Differenz der-Energien von²⁷Mg (0,844 MeV) und⁵⁶Mn (0,877 MeV) erklären lassen.Durch Auftrennung eines im thermischen Neutronenfluß von 3,5·10¹³ respektive 7·10¹³ n·cm^–2·sek^–1 bestrahlten Mg-Mn-Salzgemisches an einem Chelex-100-Ionenaustauscher und Elution mit Acetatpuffer p_H=6,25 konnte eine einwandfreie Trennung beider Nuklide bei einer vernachlässigbaren, respektive ohne Verunreinigung des eluierten Mg durch Mn erzielt werden. Die Anwendung des Verfahrens bei der Bestimmung des Mg- und Mn-Gehaltes von Reis wird beschrieben.

---

Determination of traces of magnesium and manganese in biological material by activation analysis

Summary The determination of trace amounts of magnesium in the presence of manganese in biological matrixes rendered great difficulties in the past. Activation analysis with thermal neutrons could lead to errors because of the short half-time of²⁷Mg and similarities in-energy of²⁷Mg and⁵⁶Mn (0,844 MeV and 0,847 MeV, respectively). In the present work the ionexchange chromatography using Chelex-100 resin and elution with the acetate buffer (p_H 6,25) has been employed for the separation of the mixture of Mg and Mn salts, irradiated with thermal neutron flux of 3.5 · 10¹³ n · cm^–2 · · sec^–1 or 7·10¹³ n·cm^–2·sec^–1. The results show that both elements can be obtained in the pure form, or with a very small degree of contamination of magnesium with manganese. Application of the method for the determination of the Mg- and Mn-content in rice is described.

---

---

Auszugsweise vorgetragen auf dem VI. Intern. Symposium für Mikrochemie, G-raz, September 1970.     

First application of tunable alkyl or aryl sulfinamides to the stereoselective synthesis of a chiral amine: asymmetric synthesis of (R)-didesmethylsibutramine ((R)-DDMS) using (R)-triethylmethylsulfinamide ((R)-TESA)

A highly diastereoselective addition of i-BuLi to a triethylmethylsulfinamide derived aldimine was used as the key step in the first asymmetric synthesis of (R)-didesmethylsibutramine, a metabolite of sibutramine for the potential treatment of CNS disorders. [reaction: see text]