Identification of a novel series of alkylitaconic acids in wood cultures of Ceriporiopsis subvermispora by gas chromatography/mass spectrometry.

A novel series of long-chain unsaturated dicarboxylic acids consisting of a long aliphatic chain attached to the C-3 position of itaconic acid has been identified by gas chromatography/mass spectrometry during in vitro decay of eucalypt wood by the white-rot basidiomycete Ceriporiopsis subvermispora. The major compounds were identified as tetradecyl-, 7-hexadecenyl- and hexadecylitaconic acids by their mass fragmentation patterns. Other members of the same compound series, identified as dodecanyl-, tridecanyl-, tetradecenyl-, pentadecanyl-, octadecenyl- and octadecanylitaconic acids, were present in very minor amounts or traces. Whereas hexadecenylitaconic acid has already been reported in cultures of C. subvermispora, to our knowledge this is the first report of the presence of the other alkylitaconic acids in fungal cultures. These new alkylitaconic-type metabolites may constitute a source for peroxidizable lipids involved in lignin degradation during wood decay by C. subvermispora and other white-rot basidiomycetes.     

Coherent-mode representation of supercontinuum

We apply the coherent-mode expansion to correlation functions used to describe the coherence properties of supercontinuum generated in nonlinear ?bers. We show that the leading term of the expansion represents the quasi-coherent part of the ?eld while the quasi-stationary part is embedded into the higher-order modes. The evolution of the modal expansion and the number of modes needed to describe the supercontinuum ?eld are also discussed.     

The lamellar phase of the sodium dodecylsulfate/decanol/toluene/formamide system: NMR and phase studies of solubilization

The phase behavior of the system sodium dodecylsulfate/decanol/toluene/ formamide was investigated and pseudo-ternary diagrams established. In particular, the effect of varying the amount of toluene in the system on the stability of the lamellar phase region was studied in detail. Deuterium NMR and low-angle x-ray diffraction measurements showed that more toluene was distributed between the surfactant chains as the amount of decanol in the system is reduced, resulting in a more disordered dynamic structure in the bilayers. Similarly, increased formamide content lead to greater penetration of the toluene into the bilayer and more disorder. Both factors were found to be instrumental in decreasing the stability of the lamellar structure.     

A dielectric study of 1-alcohol — tetraethyl orthosilicate mixtures

Dielectric properties of mixtures of 1-alcohols (ethanol, 1-butanol and 1-hexanol) and tetraethyl orthosilicate (TEOS) were determined by means of the time domain method (TDS). To all spectra were fitted a model function containing a sum of three debye relaxation terms with fixed ₂ and ₃. Initially, to 2–3 mole%, TEOS did not influence static permittivity nor main relaxation time of the alcohol. For higher concentrations there is a linear decrease in both these parameters. Qualitatively the effects of TEOS are comparable with those of a nonpolar hydrocarbon on the alcohol structure.     

Gelled emulsions with a high water content

The structure of a gel containing 99% water, 0.5% of a nonionic surfactant and 0.5% of a hydrocarbon was investigated by analysis of its equilibrium phases and their state of dispersion by liquid helium freeze fracture electron microscopy.The gel consisted of aqueous droplets of micron size separated by a thin membrane of a lamellar liquid crystal and a W/O microemulsion with droplets varying between 200 and 1000 Å in diameter.     

Phase equilibria and structures in the system glycerol,sodium dodecyl sulfate and decanol

The phase equilibria and structures in the system glycerol, sodium dodecyl sulfate and decanol were determined using visual observation, optical microscopy, and low angle X-ray diffraction.The results showed the presence of an isotropic liquid alcohol solution of the surfactant and the glycerol, a lamellar liquid crystalline phase and a small region of an isotropic glycerol solution.     

W/O microemulsions of styrene monomer and dimer

The reason for the lower water solubility in W/O microemulsions of the styrene dimer, trans, trans-1,4-diphenyl-1,3-butadiene, in comparison with the monomer was investigated by determining the phase equilibria in the microemulsion system with pentanol as the cosurfactant and sodium dodecyl sulfate as the surfactant. The main factor for the low tolerance for water in the system was the incompatibility of the dimer with the cosurfactant and surfactant.     

Influence of the short-range coordination order of erbium ions on excitation migration and upconversion in multicomponent glasses

Applying a pair-correlation function of erbium ions that is known from x-ray absorption fine structure spectroscopy, we develop a new statistical model of migration-assisted upconversion in erbium-doped glasses. The results of modeling show that short-range coordination order of erbium ions contributes to the upconversion rate for both low and high population inversion. In addition, we report the methods of suppression of the short-range order of erbium ions in multicomponent glasses.     

Decrease in spatial coherence of light propagating in free space

It is shown that a highly spatially incoherent light distribution may be generated from a highly coherent one on propagation in free space. This result essentially demonstrates that there exists an inverse of a classic result of optical coherence theory, namely, the van Cittert-Zernike theorem. The analysis also indicates that the technique of phase conjugation may be used to reverse changes in the coherence properties of light, at least those which are generated on propagation in free space.