Degradation of Amino-(3-methoxyphenyl)methanephosphonic Acid by Alternaria sp

Alternaria sp. isolated from the surface of carrot ( Daucus carota ) seeds appeared to be able to degrade amino-(4-methoxyphenyl)-methanephosphonic acid using it as a sole source of carbon, nitrogen, and phosphorus for growth.     

Particle tunneling and scattering in a three-dimensional potential with a barrier

The particle tunneling through a 3-D rectangular potential barrier has been studied. The simplest model for multiple internal reflections has been assumed. The explicit expression for all the transmission and reflection probability amplitudes have been derived, as well as the tunneling and reflection phase times.      

On translations of subsets of the real line

In this paper we discuss various questions connected with translations of subsets of the real line. Most of these questions originate from W. Sierpinski. We discuss the number of translations a single subset of the reals may have. Later we discuss almost invariant subsets of Abelian groups.

     

Continuous monitoring of thermooxidative degradation products of polystyrene by membrane extraction with sorbent interface and gas chromatography

A novel method for the continuous monitoring of thermooxidative degradation products of polystyrene by membrane extraction with sorbent interface (MESI) and gas chromatography (GC) is developed. The results are compared with solid-phase microextraction-GC, which can extract gases, vapors, and aerosols. The volatile and semivolatile degradation products are identified by mass spectrometry. The membrane used in the MESI-GC analysis shows a high permeation for volatile aromatic hydrocarbons; a low permeation for corresponding volatile aldehydes; and no permeation for less volatile alcohols, acids, and degradation products with a high molecular weight, thus reducing significantly the number of compounds detected from MESI-GC. Sensitivity of the method depends on the time of trapping, which is limited by the breakthrough of the trap. By heating the trap at fixed intervals of time, consecutive gas chromatograms are obtained.     

Folding of aromatic oligoimides of trans-1,2-diaminocyclohexane

Chiral oligomeric diimides prepared from pyromellitic dianhydride, (R,R)-1,2-diaminocyclohexane and phthalic anhydride fold into M or P helical conformers; trimer 1 folds into the P conformer in the crystal but the M conformer dominates in solution; longer chain oligomers 2 and 3 form preferentially P conformers in solution, as a result of intermolecular interactions.     

Beyond Flory-Huggins theory: new classes of blend miscibility associated with monomer structural asymmetry

Flory-Huggins (FH) theory is restricted to polymer mixtures whose monomers are structurally identical, a situation limited to isotopic blends and computer simulations. We investigate the influence of monomer structure on blend miscibility and scattering properties using the lattice cluster theory generalization of the FH model. Monomer structural asymmetry is shown to profoundly affect blend miscibility (T(c),phi(c)), chain swelling (T(theta)), and the scale (xi) and intensity [S(0)] of composition fluctuations. Four distinct blend miscibility classes are identified and experimental evidence for these classes is discussed.