Titanium and carbon implantation of iron

Pure iron foils have been implanted with Ti and with Ti plus C and characterized by conversion electron Mössbauer spectroscopy (CEMS) and Auger electron spectroscopy (AES). Both paramagnetic and magnetic phases are observed and attributed to amorphous Fe?Ti?C alloys of differing Ti and C contents. Estimates of the thicknesses of the amorphous layers based on the CEMS data are in good agreement with the AES concentration depth profiles.     

Citrafungins A and B, two new fungal metabolite inhibitors of GGTase I with antifungal activity

[structure: see text] Screening of natural products extracts led to the discovery of citrafungins A and B, two new fungal metabolites of the alkylcitrate family that are inhibitors of GGTase I of various pathogenic fungal species with IC(50) values of 2.5-15 microM. These compounds exhibited antifungal activities with MIC values of 0.40-55 microM. The isolation, structure elucidation, relative and absolute stereochemistry, and biological activities of citrafungins are described.     

Characterization of an epithermal irradiation facility

An epithermal energy neutron irradiation facility has been used to perform instrumental activation analysis for iodine, silicon, nickel, zirconium, uranium and thorium. The facility, which is adjacent to the fuel of the University of Virginia 2.0 MW pool reactor, consists of a dry sample region surrounded by a fixed cadmium shield. A boron nitride capsule can be used to hold the sample in the cadmium facility to further enhance the reduction of thermal neutron activation. The neutron fluence rate is 2.2×10¹⁶ n·m^–2·s^–1 for fission spectrum energy neutrons (measured with Ni(n,p)Co) and 8.2·10¹⁵ n·m^–2·s^–1 for resonance energy neutrons (measured with gold).Iodine has been measured at concentrations as low as 0.1 mg/kg with 3% counting statistics in powdered infant formula and 0.15 mg/kg with 5% statistics in liquid infant formula. Silicon has been measured at concentrations of 0.2% in biological samples with counting statistics between 5 and 10% and in coal and soil at concentrations greater than 4% with better than 1% statistics. Nickel has been measured in coal and soil at the 20 mg/kg level and higher with 6% statistics. Zirconium has been determined at 600 mg/kg and greater in ceramics with counting errors less than 3%. Uranium and thorium have been measured at the 10 mg/kg level with 3% counting statistics.     

VUV laser-induced fluorescence of molecular hydrogen

State-selective detection of molecular hydrogen by VUV laser-induced fluorescence has been achieved at excitation wavelengths greater than the lithium fluoride cut-off, using xenon as the non-linear medium. With this approach sensitivities of ≈10⁹ per cm³ per quantum state have been achieved under cell conditions. This method provides a simple approach to monitoring the vibrational state distribution of hydrogen and its isotopes.