X-ray determination of the mean amplitudes of vibration and debye temperatures of some rare earth monochalcogenides

The x-ray diffraction intensities of Bragg reflections have been measured at room temperature for thulium selenide, samarium sulphide, samarium selenide and samarium telluride. On the basis of a common amplitude approximation, the Debye-Waller factor, the mean amplitude of vibration and the Debye temperature have been evaluated. The values of the Debye temperatures and mean amplitudes of vibration are 176±16°K, 0·185 ± 0·017 Å (TmSe), 155 ± 7°K, 0·244 ± 0·012 Å (SmS), 153 ± 14°K, 0·221 ± 0·020 Å (SmSe) and 151 ± 20°K, 0·204 ± 0·027 Å (SmTe).     

Berkeleydione and berkeleytrione, new bioactive metabolites from an acid mine organism

[structure: see text] Two novel hybrid polyketide-terpenoid metabolites were isolated from a Penicillium sp. growing in the Berkeley Pit Lake of Butte, Montana. Their structures were deduced by spectroscopic analysis and confirmed by single-crystal X-ray analysis on berkeleydione (1). Both compounds inhibited matrix metalloproteinase-3 and caspase-1, and berkeleydione showed activity toward non-small-cell lung cancer in NCI's human cell line antitumor screen.     

Surface core level shift observed on NiAl(1 1 0)

Using high resolution core level spectroscopy, a surface core level shift towards lower binding energy of −0.13 eV is determined for the 2p level of the outwardly relaxed Al surface atoms on NiAl(1 1 0). Density functional theory based calculations with inclusion of final state effects yield a value of −0.14 eV for this shift in excellent agreement with experiment. We show that the initial state approximation yields a value of +0.09 eV, i.e. the inclusion of final state relaxation effects is vital not only to obtain the correct value but even the correct sign for this shift.     

Plocamenone,a unique halogenated monoterpene from the red alga,plocamium

The unique halogenated monoterpene, 7-bromo-2,6-dimethyl-4,4,8-trichloro-1,5(z)-octadiene-3-one, was isolated from the marine red alga $\text{Plocamium}$.     

SXNS13: Surface X-ray and Neutron Scattering Conference in Hamburg

The 13th Surface X-ray and Neutron Scattering Conference took place from July 7–11, 2014, on the DESY site in Hamburg, Germany. The meeting was attended by about 140 participants from all over the world.     

A surface x-ray study of the structure and morphology of the oxidized Pd001 surface

The oxidation of Pd(100) and the formation of PdO was studied in situ using surface x-ray diffraction. A bulklike, epitaxial PdO film is formed at oxygen partial pressures beyond 1 mbar and sample temperatures exceeding 650 K. The main orientation is PdO(001)/Pd(001), based upon bulk reflections from the PdO film. By comparing with measurements from the Pd crystal truncation rods, we estimate an rms surface roughness of 6 A, in good agreement with previous high pressure scanning tunneling microscopy measurements. Finally, we observed the transformation from the (radical5 x radical5) surface oxide to PdO bulk oxide at 675 K and 50 mbar O(2) pressure.     

Berkelic acid, a novel spiroketal with selective anticancer activity from an acid mine waste fungal extremophile

Berkeley Pit Lake is an abandoned open-pit copper mine filled with 30 billion gallons of acidic, metal-contaminated water. This harsh environment is proving to be a source of unusual microorganisms that produce novel bioactive metabolites. Bioassay-guided fractionation using signal transduction enzyme assays led to the isolation of the novel spiroketal, berkelic acid 1, and of the known gamma-pyrone, spiciferone A 4. Berkelic acid has shown selective, nanomolar activity against OVCAR-3, an ovarian cancer cell line in the National Cancer Institute cell line screen. The isolation and characterization of these compounds are reported here.