Channel capacity of the ribosome.

Translation is one of the most fundamental processes in the biological cell. Because of the central role that translation plays across all domains of life, the enzyme that carries out this process, the ribosome, is required to process information with high accuracy. This accuracy often approaches values near unity experimentally. In this paper, we model the ribosome as an information channel and demonstrate mathematically that this biological machine has information-processing capabilities that have not been recognized previously. In particular, we calculate bounds on the ribosome's theoretical Shannon capacity and numerically approximate this capacity. Finally, by incorporating estimates on the ribosome's operation time, we show that the ribosome operates at speeds safely below its capacity, allowing the ribosome to process information with an arbitrary degree of error. Our results show that the ribosome achieves a high accuracy in line with purely information-theoretic means.

Evaluation of electrochemical properties of nanostructured metal oxide electrodes immersed in redox-inactive organic media.

This paper describes analysis of dropcast nanocrystalline and electrochemically deposited films of NiO and α-Fe2O3 as model metal oxide semiconductors immersed in redox-inactive organic electrolyte solutions using electrochemical impedance spectroscopy (EIS). Although the data reported here fit a circuit commonly used to model EIS data of metal oxide electrodes, which comprises an RC circuit nested inside a second RC circuit that is in series with a resistor, our interpretation of the physical meaning of these circuit elements differs from that applied to EIS measurements of metal oxide electrodes immersed in redox-active media. The data presented here are most consistent with an interpretation in which the nested RC circuit represents charge transfer between the metal oxide film and the underlying metal electrode, and the non-nested RC circuit represents the resistance and capacitance associated with formation of a charge-compensating double-layer at the exposed interface between the metal electrode and electrolyte solution. Applying this interpretation to analysis of EIS data collected for metal oxide films in organic media enables the impact of film morphology on electrochemical behavior to be distinguished from the effects of the intrinsic electronic structure of the metal oxide. This distinction is crucial to the evaluation of nanostructured metal oxide electrodes for electrochemical energy storage and electrocatalysis applications.

Metaphase FISHing of transgenic mice recommended: FISH and SKY define BAC-mediated balanced translocation.

The evolving trend to use larger transgenes and their associated increased chance of unexpected genetic events mandates more careful characterization of transgenic mice. In characterizing our five new mouse strains transgenic for the BAC, bEMS4, we have identified the highest copy number reported to date: the stable incorporation of approximately 40 copies of a 194-kb expressed transgene in a single insertion site. We caution, however, that standard molecular techniques failed to identify a balanced translocation in another strain, and an inappropriate site of insertion in a third. Molecular cytogenetic analysis using metaphase FISH was the minimum level of characterization needed to reveal these unexpected genetic events. In addition, we combined FISH and SKY to identify the transgene at the breakpoints of the balanced translocation, t(3;9). This is the first description of a BAC-mediated chromosomal rearrangement and the first application of SKY to identify transgene-induced chromosomal rearrangements.