The formation and behavior of self-assembled monolayers made of n-dodecaneselenol (DDSe) on Au(111) as a blocking dielectric medium toward heterogeneous electron-transfer were assessed by electrochemical impedance spectroscopy. Microelectrode array theory was applied to study the growth kinetics of the self-assembled monolayer. The results show that adsorption from a n-dodecaneselenol solution in ethanol can be described using two different time constants. The monolayer is formed within the first minute after the electrode has been brought into contact with the deposition solution. The second step involves film reorganization and self-ordering, which can last for several hours. LA0203483

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Young-of-the-year and yearling northern pike (Esox lucius), yearling yellow perch (Perca flavescens) and adult crayfish (Orconectes virilis) were collected in the mercury-contaminated Wabigoon/English/Winnipeg River System, Ontario, and analyzed for total mercury. Analysis of mercury concentrations in these organisms produced consistent geographical trends; i.e. mercury concentrations in biota downstream of Dryden > English River system > Winnipeg River system > control sites. In the Wabigoon River system the bioavailability of mercury increases with distance downstream of the historical point source. Mercury concentrations in the biota studied were highly correlated with mercury concentrations in fish species which are of sport and commercial interest. The locations where young fish obtain their bodyburdens are known typically within 100 m. The biota studied compare favourably with the criteria proposed by Phillips (1980) as prerequisites for biological indicators. The wide distribution of young pike, perch and crayfish in North America, Europe and Asia may enhance their appeal as biomonitors.

A 10% ASK Smartcard ASIC achieves 3e-10 BER in the presence of digital noise. A 2000 times reduction in digital signature amplitude greatly improves security against DPA attack. Voltage compliance is maintained for more than two decades of received power. The 2.8-mm X 2.9-mm ASIC is fabricated in a 0.6 micron CMOS process with EEPROM.

The retention of both underivatized and carboxylated polystyrene latex beads by electrical field-flow fractionation (EIFFF) was investigated using a 2 mM aqueous solution of quinonehydroquinone as the carrier liquid. The quninone-hydroquinone redox couple passes current with less polarization of the electrodes than carrier liquids previously employed. Underivatized beads, ranging in diameter from 0.15 to 0.74 μm eluted in the normal mode, while carboxylated beads larger than 1 μm eluted in the steric mode. Normal mode retention increases with flow rate, probably due to shearing of the polarization layer, which increases the working field. At a constant field and flow rate, normal-mode retention is inversely related to the product of a particle\u27s size and electrophoretic mobility, in accordance with retention theory. Thus, ElFFF can be used to obtain both the size and electrophoretic mobility of particle suspensions