A solid-phase chemiluminescence immunoassay for 17α-methyltestosterone

A solid-phase immunoassay based on chemiluminescence detection is described for the anabolic steroid 17α-methyltestosterone (MT). The reproducibility is increased substantially by introduction of the solid-phase principle and the assay can therefore be used to quantify MT in bovine urine. The detection limit is 10 pg.     

Soft X-ray resonant magnetic scattering of magnetic nanostructures

Soft X-ray resonant magnetic scattering offers a unique element-, site- and valence-specific probe to study magnetic structures on the nanoscopic length scale. This new technique, which combines X-ray scattering with X-ray magnetic circular and linear dichroism, is ideally suited to investigate magnetic superlattices and magnetic domain structures. The theoretical analysis of the polarization dependence to determine the vector magnetization profile is presented. This is illustrated with examples studying the closure domains in self-organising magnetic domain structures, the magnetic order in patterned samples, and the local configuration of magnetic nano-objects using coherent X-rays. To cite this article: G. van der Laan, C. R. Physique 9 (2008).     

Non-reciprocal X-ray linear dichroism

Recently, a new optical effect was observed by Goulon, Rogalev, Goulon-Ginet, Benayoun, Paolasini, Brouder, Malgrange & Metcalf [Phys. Rev. Lett. (2000), 85, 4385-4388] using linearly polarized synchrotron radiation. The authors have correctly analysed the effect using the mathematical framework of Buckingham and Barron. A brief review is given with the underlying simplicity discussed from a symmetry point of view.     

Harsanyi power solutions for graph-restricted games

We consider cooperative transferable utility games, or simply TU-games, with limited communication structure in which players can cooperate if and only if they are connected in the communication graph. Solutions for such graph games can be obtained by applying standard solutions to a modified or restricted game that takes account of the cooperation restrictions. We discuss Harsanyi solutions which distribute dividends such that the dividend shares of players in a coalition are based on power measures for nodes in corresponding communication graphs. We provide axiomatic characterizations of the Harsanyi power solutions on the class of cycle-free graph games and on the class of all graph games. Special attention is given to the Harsanyi degree solution which equals the Shapley value on the class of complete graph games and equals the position value on the class of cycle-free graph games. The Myerson value is the Harsanyi power solution that is based on the equal power measure. Finally, various applications are discussed.     

Intersection theorems on polytopes

Received June 6, 1995 / Revised version received May 26, 1998 Published online October 9, 1998     

Characterization of the Reverse Talmud bankruptcy rule by Exemption and Exclusion properties

The Reverse Talmud rule for bankruptcy problems applies the Constrained Equal Awards rule (CEA rule) for ‘large’ amounts of the estate, while it applies the Constrained Equal Losses rule (CEL rule) for ‘small’ amounts of the estate. The CEA rule, respectively CEL rule, can be axiomatized using the Exemption and Exclusion properties respectively. There is no rule that satisfies both these two properties. In this paper we axiomatize the Reverse Talmud rule by using compatible weaker versions of the Exemption and Exclusion properties.     

Charge carrier mobilities in liquid crystalline mesomorphic poly(DI-n-Alkylsilylene)s; influence of backbone conformation

The charge transport properties of a series of symmetrically substituted mesomorphic poly(di-n-alkylsilylene)s are studied using the pulse-radiolysis time resolved microwave conductivity (PR-TRMC) technique. The observed conductivities for these polymers could be correlated with different backbone conformations present both in the crystalline solid phase and in the liquid crystalline mesophase. The transition from the solid phase to the mesophase is accompanied by a disordering of the silicon backbone that results in a decrease of the conductivity of up to two orders of magnitude. The charge carrier mobilities found varied from 5×10⁻⁵ m² /Vs for the all-trans conformation in the solid phase to 6×10⁻⁷ m² /Vs for the disordered backbone conformation in the mesophase. The anisotropic radiation-induced conductivity observed for aligned poly(di-n-hexylsilylene) samples demonstrate that charge carrier migration takes place preferentially in the direction of the polymer backbone.