Manganese(III) acetate mediated synthesis of oxygen heterocycles. Influence of copper(II) salts on product distribution

Unsaturated malonates bearing pendant alcohols yield carbocycles tethered to oxygen heterocycles on exposure to manganese(iii) acetate and an appropriate copper(ii) salt.     

Variability in the chemical contamination effects of gun shot

This is a contribution to a larger study aimed at development of a technique to determine the origins of waterfowl from their feather chemistry, using automated X-ray fluorescence spectrometry. Since feather samples commonly come from shot birds, an effort was made to measure the contamination effects of shot using cotton cloth to simulate feathers. At pointblank ranges contamination can include the elements Ba, Sb, Pb, Cu, S and likely others depending on the exact composition of both gun powder and shot. At greater ranges (12.5 to 50 yards – 14.4 to 45 m) significant contamination resulting from 12 gauge No. 2 shot came only from lead, with some zinc contamination probable at the extreme range used. Lead contamination increased with increasing range, and apparently has a curvelinear relationship with pellet velocity. This knowledge might permit prediction, after the fact, of ranges from which shot has been fired.     

Structure and synthesis of SSZ-63: toward an ordered form of zeolite beta

The synthesis, characterization, and structure elucidation of the borosilicate zeolite SSZ-63 are described. SSZ-63 is synthesized using the 1-cyclodecyl-1-methylpyrrolidinium cation as a structure-directing agent. The structural model for SSZ-63 was determined by comparison of its powder X-ray diffraction pattern with those of zeolite beta and its polytype structures. Whereas conventional zeolite beta may be described as a random intergrowth of polytypes A and B, SSZ-63 is more accurately described as a random intergrowth of polytypes B and C(H) (the hypothetical polytype C proposed by Higgins). Polytype C(H) is essentially an ordered intergrowth (of polytypes A and B) in which one of the crystallographic projections is equivalent to those in polytype A and another projection is equivalent to those in polytype B. Unlike zeolite beta, which possesses significant disorder related to layer shifts along both the a- and b-crystallographic axes, the structure of SSZ-63 has little disorder associated with the translations of layers in the a-direction. DIFFaX simulations of the powder diffraction patterns, electron diffraction, and high-resolution transmission electron microsocopy data all support the proposed model.     

Limit theorems for functionals of mixing processes with applications to -statistics and dimension estimation

In this paper we develop a general approach for investigating the asymptotic distribution of functionals of absolutely regular stochastic processes . Such functionals occur naturally as orbits of chaotic dynamical systems, and thus our results can be used to study probabilistic aspects of dynamical systems. We first prove some moment inequalities that are analogous to those for mixing sequences. With their help, several limit theorems can be proved in a rather straightforward manner. We illustrate this by re-proving a central limit theorem of Ibragimov and Linnik. Then we apply our techniques to -statistics

with symmetric kernel . We prove a law of large numbers, extending results of Aaronson, Burton, Dehling, Gilat, Hill and Weiss for absolutely regular processes. We also prove a central limit theorem under a different set of conditions than the known results of Denker and Keller. As our main application, we establish an invariance principle for -processes , indexed by some class of functions. We finally apply these results to study the asymptotic distribution of estimators of the fractal dimension of the attractor of a dynamical system.

     

Impact of the physical and topographical characteristics of adsorbent solid-phases upon the fluidised bed recovery of plasmid DNA from Escherichia coli lysates

A comparison is made of the performance of two types of adsorbent solid phases (commercially sourced Streamline composites and custom-assembled Zirblast pelliculates), derivatised with similar anion exchange chemistries and applied to the recovery of plasmid DNA from Escherichia coli extracts prepared by chemical lysis and coarse filtration. Streamline and Zirblast adsorbents were characterised by average particle diameters of 200 and 95 microm, densities of 1.16 and 3.85 g/m2, and small ion capacities of 170 and 8 micromol/ml settled adsorbent, respectively. Detailed analysis of products and impurities in a full operational cycle of adsorption, washing, pre-elution, elution and regeneration processes was enabled by the harnessing of a battery of analyses for nucleic acid and organic solute content of feedstocks and bed effluents exploiting ultra-violet spectrophotometry, agarose gel electrophoresis and specific reactions with the fluorescent probe PicoGreen. In comparative tests operated under near identical conditions, Streamline and Zirblast adsorbents exhibited plasmid recoveries of 76 and 90% of bound product characterised by purity ratios (relative PicoGreen and A254 estimates of mass) of 9 and 32, respectively. Conclusions are drawn regarding the specific impact of the physical and topographical characteristics of solid-phase geometry upon product throughput, achievable product purity, process time-scales and operational economics for the manufacture of plasmid DNA.     

Intramolecular PhI=O mediated copper-catalyzed aziridination of unsaturated sulfamates: a new direct access to polysubstituted amines from simple homoallylic alcohols

[reaction: see text] Olefinic sulfamates derived from primary and secondary alcohols undergo intramolecular copper-catalyzed aziridination in the presence of iodosylbenzene to afford novel bicyclic fused aziridines. The latter were opened by various nucleophiles to give the corresponding substituted cyclic sulfamates, which in turn reacted, after nitrogen activation, with a second nucleophile at the carbon atom bearing the oxygen atom. Concomitant removal of the sulfonyloxy moiety thus gave access to polysubstituted amines.     

On the irreducibility of the iterates of

Let be a field and suppose that is irreducible in . We discuss the following question: under what conditions are all iterates of irreducible over ?

     

Three Controls are Better than One: A Computational Model of Complex Control Systems

This paper investigates theories that integrate and extend currently accepted agency- and transaction-based approaches to organizational control. We use a computational model to build three forms of control systems (market, bureaucratic, clan) and three forms of control targets (input, behavior, output). Using these models, we examine relationships between control systems and both singular and multiple control targets. Results of this study support the emerging broader perspective on organizational control research and suggest that managers can improve organizational performance by focusing attention on multiple control targets. In addition, findings partially support posited relationships between control systems and singular control targets. The authors suggest that results of this study should direct scholars to refocus control research from examinations of singular forms of control to evaluations of more complex control systems.