Eigenvalues of a statistical mechanics matrix

We consider the problem of finding the spectrum of an n × n matrix which arises in the study of a certain model of long-range interactions in a one-dimensional statistical mechanics system. Our analysis exhibits a curious resemblance of the suitably normalized distribution of eigenvalues to the Marčenko–Pastur law in the limit n → ∞.     

Fundamental and practical aspects in the design of nanoscaled SnO2 gas sensors: a status report

Gas sensors based on semiconducting materials have become of great interest to both sensor users and researchers. In this context, a huge number of publications have appeared in the literature which deal with metal oxide gas sensors, in general, and with the prototype material SnO₂, in particular. The amount of data published grows continuously and has led to a situation in which even experts in this field tend to lose an overview. The present review describes the reasons for this complexity and outlines unifying concepts to understand the huge amount of published, mostly empirical data. This leads to a comprehension of gas-sensing phenomena in both the application and research domains. Received: 7 December 1998 / Revised: 6 May 1999 / Accepted: 19 May 1999     

Exclusively Heteronuclear NMR Experiments to Obtain Structural and Dynamic Information on Proteins

Provided that ¹³C‐detected NMR experiments are either preferable or complementary to ¹H detection, we report here tools to determine C^α? C′, C′? N, and C^α? H^α residual dipolar couplings on the basis of the CON experiment. The coupling constants determined on ubiquitin are consistent with the subset measured with the ¹H‐detected HNCO sequences. Since the utilization of residual dipolar couplings may depend on the mobility of the involved nuclei, we also provide tools to measure longitudinal and transverse relaxation rates of N and C′. This new set of experiments is a further development of a whole strategy based on ¹³C direct‐detection NMR spectroscopy for the study of biological macromolecules.     

Elementare Eigenschaften lokaler–Polynom–Schätzer: ein Streifzug durch die lineare Algebra

Zusammenfassung. Der lokale–Polynom–Sch?tzer besteht darin, an eine Sequenz von aufeinanderfolgenden Datenpunkten lokal ein Polynom anzupassen und damit zuf?llige Schwankungen in den Daten wegzugl?tten. Dieser Ansatz gewinnt in der nichtparametrischen Kurvensch?tzung st?ndig an Bedeutung. Es wird gezeigt, wie die Herleitung einiger elementarer Eigenschaften dieses Handwerkszeuges des Datenanalytikers einen Streifzug durch die lineare Algebra erforderlich macht. Eingegangen am 27.03.1998 / Angenommen am 15.06.1998     

Norcholanic acids as substrates for recombinant 3β-hydroxysteroid dehydrogenase and progesterone 5β-reductase, enzymes of the 5β-cardenolide biosynthesis

The conversion of 23-nor-5,20(22)E-choladienic acid-3β-ol and other intermediates of the putative norcholanic acid pathway of cardenolide biosynthesis by recombinant 3β-hydroxysteroid dehydrogenase from Digitalis lanata in dehydrogenation and reduction reactions was investigated. 23-nor-4,20(22)E-choladienic acid-3-one was found to be a substrate of recombinant progesterone 5β-reductases from D. lanata and Arabidopsis thaliana. The role of various substrates in cardenolide biosynthesis is discussed.