Effects of RAMEB on Bioremediation of Different Soils Contaminated with Hydrocarbons

The limiting factor of soil remediation is often the low accessibility of the pollutants.Laboratory experiments have been carried out to investigate the effect of the randomlymethylated cyclodextrin (RAMEB) on bioremediation of various types of soils spikedwith Diesel and transformer oil and also on actual site soils contaminated with poorlydegradable mazout. The contaminated soil in the aerobic solid phase microcosm-experiments was amended with nutrients and supplemented with different amounts of RAMEB. An integrated chemical-biological-ecotoxicological methodology was applied to follow the bioremediation. The laboratory study proved the bioremediation enhancing effect of RAMEB both on artificially contaminated soils and on actual site mazout contaminated soils. RAMEB activated soil microbes by improving the bioavailability of the contaminants and accelerating biodegradation. Efficacy of RAMEB was influenced both by contaminantand environment related factors, such as the type and concentration of the pollutinghydrocarbons and characteristics of the soil.     

Analysis of poly(amidoamine)-succinamic acid dendrimers by slab-gel electrophoresis and capillary zone electrophoresis

Ethylenediamine (EDA)-core poly(amidoamine) (PAMAM) succinamic acid dendrimers (Ex.SAH, where x refers to the generation) were synthesized and analyzed by polyacrylamide gel electrophoresis (PAGE), size-exclusion chromatography (SEC), potentiometric acid-base titration, and capillary zone electrophoresis (CZE). Various generations (E1.SAH-E7.SAH) PAMAMs and a succinamic acid terminated core-shell tecto(dendrimer) (E5(E3.SAH)(n)) were first analyzed by PAGE. PAGE results show that the relative mobilities of generation 2 to generation 7 dendrimers decreased with the increasing number of generations. The molecular mass of a generation 5 core generation 3 shell tecto(dendrimer) (denoted as E5(E3.SAH)(n)) was determined to be between the Mw of E6.SAH and E7.SAH. CZE analysis allowed the evaluation of electrophoretic properties of given-generation dendrimers. The electrophoretic mobilities of individual generations PAMAM polyanions are similar, indicating that the separation mainly depends on their approximately identical charge/mass ratio. The E5(E3.SAH)(n) tectodendrimer had a lower electrophoretic mobility, which was consistent with its lower charge/mass ratio. The combination of PAGE and CZE analysis provides an alternative and effective way to characterize this group of PAMAM-succinamic acid dendrimers.     

Forced nonlinear oscillations of elastic membranes

An initial-boundary-value problem is considered for the spatially two-dimensional damped Boussinesq equation with a forcing term. The problem in question is argued to serve as a model for describing small nonlinear oscillations of a circular membrane under the influence of acoustic pressure. Eigenfunction expansion method is used for constructing the global-in-time solution of the problem in question. Existence and uniqueness follow from the construction. Long-time asymptotics is computed on the basis of the obtained series representation. Numerical simulations are conducted. The algorithm shows excellent convergence properties.     

Fe–Ag granular multilayers and heterostructures studied in applied magnetic field

An (0.2 nm ⁵⁷Fe / 2.6 nm Ag)₇₅ granular multilayer sample and heterostructures with additional continuous Fe layers in different sequences were studied in magnetic field applied at different temperatures. The broadening of the superparamagnetic lines was found to be very similar for the three samples in applied fields both parallel and perpendicular to the sample plane. While the layer sequence has no significant effect on the superparamagnetic properties, the continuous magnetic layers follow a different approach to saturation in perpendicular magnetic fields.     

The Klee–Minty random edge chain moves with linear speed

An infinite sequence of 0's and 1's evolves by flipping each 1 to a 0 exponentially at rate 1. When a 1 flips, all bits to its right also flip. Starting from any configuration with finitely many 1's to the left of the origin, we show that the leftmost 1 moves right with bounded speed. Upper and lower bounds are given on the speed. A consequence is that a lower bound for the run time of the random‐edge simplex algorithm on a Klee–Minty cube is improved so as to be quadratic, in agreement with the upper bound. © 2006 Wiley Periodicals, Inc. Random Struct. Alg., 2007