Aufschluß und Veraschung organischer Substanzen durch Radikale in wäßriger Lösung

The method described utilizes the OH radicals formed from the reagent H₂O₂/Fe²⁺ in aqueous solution. It is especially suitable for foodstuffs (as meat, fish, flour), biological material (as animal carcases, faeces, urine) and various chemicals. The parameters of the method have been investigated with the wet-ashing of meat as example. Mild experimental conditions, large amounts of substances which can be ashed and simple manipulation in an open system are the essential advantages in comparison with methods hitherto used. The procedure is useful for analytical decomposition and ashing, for serial operation, as a rapid method, and for destruction of waste. In the present communication it is applied to the control of environmental radioactivity in the determination of very low activities of ¹³⁷Cs in meat and to the rapid and reliable measurement of accidental contaminations.     

NHC Supersilyl Silver Complex [Ag(IPr)SitBu3] as a Promising Agent for Substitution Reactions

The NHC supersilyl silver complex [Ag(IPr)SitBu₃] (IPr = NHC_IPr) was prepared by treatment of Ag(IPr)Cl with Na(thf)₂[SitBu₃] in benzene/thf at room temperature. X-ray quality crystals of the NHC supersilyl silver complex [Ag(IPr)SitBu₃] (monoclinic, space group P2₁/m) were grown from heptane at room temperature. The ²⁹Si NMR spectrum of a solution of [Ag(IPr)SitBu₃] in C₆D₆ revealed two doublets caused by coupling to ¹⁰⁷Ag and ¹⁰⁹Ag nuclei. We further investigated the possibility of a conversion of triel halides EX₃ by treatment with [Ag(IPr)SitBu₃]. At ambient temperature the reaction of [Ag(IPr)SitBu₃] with an excess of EX₃ yielded tBu₃SiEX₂ (E = B, Al; X = Cl, Br; E = Ga; X = Cl) and IPr · EX₃ (EX₃ = BCl₃, BBr₃, AlCl₃, AlBr₃, GaCl₃). The identity of tBu₃SiEX₂ and IPr · EX₃ was confirmed by comparison with authentic samples.     

Bottom-up computational modeling of semi-crystalline fibers: from atomistic to continuum scale

A bottom-up computational approach involving Molecular Dynamics (MD) of silk fiber subunits and Finite Element (FE) simulations of whole spider silk fibers is presented. The approach is discussed with an emphasis on the benefits and bottlenecks of incorporating the atomistic and continuum models of crystalline and disordered domains in the fibers. The approach does not require any empirical parameters and it is applicable to similar semi-crystalline systems.