The visualization and endurance of fingerprints on cartridge cases after the firing process have been examined. Cartridges of M16, AK-47 (Kalashnikov) and Parabellum have been tested. Despite difficulties in visualizing these fingerprints, it was found that in some cartridge cases under laboratory conditions--for instance, on M16 brass cartridges--substantial parts of the fingerprints remain intact after shooting. The careful use of illumination after metal vapor deposition enabled visualization. Different possible mechanisms responsible for the partial destruction of the fingerprints are discussed.[on SciFinder (R)]

Fe redox chem. was studied in Lake Kinneret (Sea of Galilee), a mesotrophic, monomictic lake in the central part of the Jordan Rift Valley, Israel. Fe2+ and total Fe concns. in the epilimnion and hypolimnion were measured; relationships between Fe2+ and other parameters (e.g., light, pH) were examd. In addn., lab. expts. were conducted where filtered (biota-free) Lake Kinneret water, sterile unfiltered Lake Kinneret water, and distd. water were spiked with various Fe3+ and Fe2+ concns. Fe3+ and Fe2+ concns. were measured as a function of time in water samples under a variety of pH, O2, and radiation conditions. Fe2+ concns. in the epilimnion were below detection limits (0.04 μM) during nighttime, whereas in daytime, Fe2+ concns. were always above detection limits and changed significantly throughout the year (0.05-0.15 μM). Fe2+:Fe(tot) ratios measured in the lake (3-99%) were higher than expected values for a high pH (pH ∼8), low ionic strength (∼10 mM) aquatic system. In addn. to photo-induced redn. of Fe3+, there was strong evidence that Fe2+ is stabilized in O2-satd. lake water, since Fe2+ concns. were detected at a depth of 10 m, where <10% of light penetrates. Results of oxidn. and photoredn. expts. suggested obsd. rates of Fe redox reactions in sterile lake water were consistent with known chem. (abiotic) rates, but that these rates cannot account for obsd. Fe2+ concns. in epilimnetic water. Therefore, it was proposed that the photo-induced Fe redox cycle in the epilimnion of Lake Kinneret is largely controlled by biol. activity and that abiotic photoredn. of Fe accounts for only a small fraction of Fe2+ in the epilimnion. [on SciFinder(R)]

A two-dimensional conducting polyaniline (PAN) monolayer has been formed on an elec. insulating monolayer. The approach is based on the electrochem. polymn. of surface-confined anilinium ions that were electrostatically attached to a neg. charged self-assembled monolayer of ω-mercaptodecanesulfonate (MDS), HS(CH2)10SO3-, on a gold surface. The formation and characterization of the two-dimensional film and the MDS monolayer have been examd. by cyclic voltammetry, Fourier transform IR spectroscopy, XPS, wettability, and scanning electrochem. microscope. The formation of a capacitor-like assembly, in which electron transfer was blocked between PAN and the gold surface, was accomplished by electrochem. incorporating hexadecanethiol (C16) into the MDS monolayer. The PAN monolayer exhibits properties similar to those of a thin polymer film. [on SciFinder(R)]