Gamma rays of primary fission products from 235U(n,f) and 239Pu(n,f)

Gamma rays of primary fission products in thermal-neutron-induced fission of ²³⁵U and ²³⁹Pu were investigated. Isotopic assignments of several lines were made by comparing fission yield ratios and relative γ-ray intensities of the two fissioning nuclei. Differences between ²³⁵U and ²⁵²Cf fission product γ-ray lines are discussed.     

Quantum electrodynamics for vector mesons

Quantum electrodynamics for rho mesons is considered. It is shown that, at the tree level, the value of the gyromagnetic ratio of the rho+ is fixed to 2 in a self-consistent effective quantum field theory. Further, the mixing parameter of the photon and the neutral vector meson is equal to the ratio of electromagnetic and strong couplings, leading to the mass difference M(rho0)-M(rho+/-) approximately 1 MeV at tree order.     

Synthesis of a eta 2-2,3-diphosphabutadiene complex of zerovalent platinum from the corresponding eta 2-phosphaalkyne complex

Hydrozirconation of the eta 2-phosphaalkyne complex [Pt(dppe)(eta 2-tBuCP)] with [ZrHCl(eta 5-C5H5)2], followed by treatment with the chlorophosphaalkene ClP=C(SiMe3)2 affords the eta 2-2,3-diphosphabutadiene complex [Pt(dppe)(eta 2-tBuC(H)=PP=C(SiMe3)2]. In the presence of [Pt(PPh3)2] the latter undergoes an addition reaction with water to afford the structurally characterised Pt(II) complex [Pt(dppe)(tBuCH2P(O)HPC(SiMe3)2].     

Syntheses and characterization of two dioxygen-reactive dinuclear macrocyclic schiff-base copper(I) complexes

The dinuclear copper(I) complex [Cu(2)L(1)(CH(3)CN)(2)](ClO(4))(2) (1, L(1) = 3,6,9,17,20,23-hexaazatricyclo[23.3.1.1]triaconta-1(29),2,9,11(30),12(13),14,16,23,25,27-decaene) has been structurally characterized. As previously described, intramolecular ligand hydroxylation (at the aromatic ring) was observed when 1 was reacted with dioxygen. A stopped-flow analysis of the reaction of 1 with dioxygen under different conditions did not allow a "dioxygen intermediate" to be spectroscopically detected. Detailed NMR and electrochemical data on 1 are also presented and evaluated for the first time. No copper(II) complexes of L(1) could be characterized due to hydrolysis of the compounds. In contrast, complex 2-differing from 1 only in an increase in the size of the chelate rings-did not undergo intramolecular hydroxylation when it was oxidized. The crystal structure of 2 is also described.     

<Emphasis Type="Italic">P</Emphasis>≠<Emphasis Type="Italic">NP</Emphasis> for Infinite Time Turing Machines

We state different versions of the P=?NP problem for infinite time Turing machines. It is observed that PNP collapses to the fact that there are analytic sets which are not Borel.The author thanks J. D. Hamkins, R. Schipperus, and P. Welch for comments on earlier versions of this paper. He thanks Sanders Seliverstov for pointing out an inaccuracy in the first version of the proof of Theorem 2.10.Received April 19, 2002; in revised form June 10, 2002 Published online May 16, 2003     

Roughness evolution of ion sputtered rotating InP surfaces: pattern formation and scaling laws

The topography evolution of simultaneously rotated and Ar (+) ion sputtered InP surfaces was studied using scanning force microscopy. For certain sputter conditions, the formation of a highly regular hexagonal pattern of close-packed mounds was observed with a characteristic spatial wavelength which increases with sputter time t according to lambda approximately t(gamma) with gamma approximately 0.26. Based on the analysis of the dynamic scaling behavior of the surface roughness, the evolution of the surface topography will be discussed within the limits of existing models for surface erosion by ion sputtering.     

NN scattering in higher-derivative formulation of baryon chiral perturbation theory

We consider a new approach to the nucleon-nucleon scattering problem in the framework of the higher-derivative formulation of baryon chiral perturbation theory. Starting with a Lorentz-invariant form of the effective Lagrangian we work out a new symmetry-preserving framework where the leading-order amplitude is calculated by solving renormalizable equations and corrections are taken into account perturbatively. Analogously to the KSW approach, the (leading) renormalization scale dependence to any finite order is absorbed in the redefinition of a finite number of parameters of the effective potential at given order. On the other hand, analogously to Weinberg’s power counting, the one-pion-exchange potential is of leading order and is treated non-perturbatively.     

Asymmetric total synthesis of the indole alkaloid cyclopiazonic acid and first structure-activity data

The indole alkaloid α-cyclopiazonic acid (CPA) is one of the few known inhibitors of sarco(endo)plasmic reticulum Ca²⁺-ATPase (SERCA) besides the terpenoids thapsigargin and artemisinin. We report here the first asymmetric total synthesis of cyclopiazonic acid by a modification of the Knight synthesis, currently the most efficient route to CPA. First structure-activity data of CPA derivatives and stereoisomers are presented and will be discussed in connection with the published crystal structures of CPA-SERCA complexes.