Search for scalar top quark production in p&pmacr; collisions at sqrt

We have searched for direct production of scalar top quarks at the Collider Detector at Fermilab in 88 pb(-1) of p&pmacr; collisions at sqrt[s] = 1.8 TeV. We assume the scalar top quark decays into either a bottom quark and a chargino or a bottom quark, a lepton, and a scalar neutrino. The event signature for both decay scenarios is a lepton, missing transverse energy, and at least two b-quark jets. For a chargino mass of 90 GeV/c(2) and scalar neutrino masses of at least 40 GeV/c(2), we find no evidence for scalar top production and present upper limits on the production cross section in both decay scenarios.     

Polymer-catalyzed aminolysis of covalently imprinted cholic acid derivative

A cholic acid template bearing an acrylate functional group was copolymerized with acrylamides to generate a series of cross-linked imprint polymers. Subsequent release from the matrix by means of an aminolysis reaction showed a remarkable catalysis by the polymer surface.     

Asymptotic regularizations and shocks in noninductive heat-current-free relativistic fluids

We give here a first example of the usefulness of a method which we developed elsewhere, showing how it can give infinitesimal shock wave equations from a differential system when distribution methods fail to do so. The fluid chosen is the one indicated in the title, and the method proves to be particularly useful and easy to apply when one comes to the determination of the propagation equations.     

Biomimetic investigations from reactive lysine-derived C5 units: one step synthesis of complex polycyclic alkaloids from the Nitraria genus

A single biomimetic cascade sequence featuring intermolecular followed by intramolecular cyclizations allowed the biomimetic synthesis of nitraramine and the formation of an interesting original cage-like structure from simple C₅ lysine-derived metabolites. In the course of the study, the structure and spectral data of 1-epinitraramine were also revisited.     

NHC-catalyzed spiro bis-indane formation via domino Stetter-aldol-Michael and Stetter-aldol-aldol reactions

Two novel domino NHC-catalyzed spirocyclizations are described herein, enabling the rapid construction of three new carbon-carbon bonds and a quaternary center with high diastereoselectivity. A variety of spiro bis-indane structures are assembled in a single step from simple o-phthaldialdehyde derivatives.