The colleflaccinosides, two chiral bianthraquinone glycosides with antitumor activity from the lichen Collema flaccidum collected in Israel and Russia

Colleflaccinosides A and B, two chiral bianthraquinone glycosides from the two geographical varieties of lichen Collema flaccidum collected in Russia and Israel have been isolated as new natural products. Their structures were elucidated using UV, CD, IR, MS, 1D and 2D NMR spectral data, and chemical degradation. The colleflaccinosides B had significant antitumor activity in the crown gall tumor inhibition test.     

Binding abilities of copper to phospholipids and transport of oxalate

Monatshefte für Chemie - Chemical Monthly - Cu(II) creates complexes with dipalmitoylphosphatidylcholine (lecithin), which are detectable using electrospray ionization mass spectrometry....     

Higher‐order analogues of the Tracy‐Widom distribution and the Painlevé II hierarchy

We study Fredholm determinants related to a family of kernels that describe the edge eigenvalue behavior in unitary random matrix models with critical edge points. The kernels are natural higher‐order analogues of the Airy kernel and are built out of functions associated with the Painlevé I hierarchy. The Fredholm determinants related to those kernels are higher‐order generalizations of the Tracy‐Widom distribution. We give an explicit expression for the determinants in terms of a distinguished smooth solution to the Painlevé II hierarchy. In addition, we compute large gap asymptotics for the Fredholm determinants. © 2009 Wiley Periodicals, Inc.     

3D high-resolution acoustic imaging of the sub-seabed

Chirp sub-bottom profilers are marine acoustic devices that use a known and repeatable frequency-modulated source signature to produce vertical seismic reflection cross-sections of the sub-seabed. Here a 3D Chirp system is described that operates in the frequency range of 1.5-13 kHz, to produce a three-dimensional image of the sub-seabed, with typical penetration of 10-30 m and decimetric horizontal and vertical resolution. The system design incorporates a rigid frame that contains the Chirp source array together with 60 receiver elements, with positioning provided by an integrated real-time-kinematic (RTK) global positioning system (GPS). The system can be surface towed from a small survey vessel and can be applied to targets of marine geological, engineering, archaeological and defence interest. Data acquisition and processing are described for a case study which images a buried engineering structure in the Port of Southampton.