Diaphorase was hydrophobically immobilized onto a self-assembled monolayer of alkanethiol at an interdigitated Au microarray. The diaphorase activity at the array substrates was imaged with the scanning electrochem. microscopy (SECM) in the presence of NADH and ferrocenemethanol as a redox mediator. The images demonstrate that diaphorase was immobilized onto the SAM layer to form a line-and-space micropattern which reflected the pattern of the Au microarray. [on SciFinder(R)]
Anharmonic correlation-corrected vibrational self-consistent-field (CC-VSCF) calculations are reported for the neutral HXeI molecule. Fundamental, overtone and combination frequencies and their absorption intensities are computed, and compared with previous and new experimental data from FTIR matrix isolation measurements. Agreement between experiment and calculations extend the identification of the HXeI molecule, and the calculations prove useful in aiding assignment of new observed transitions. The results show that especially the Xe-H bond of HXeI is highly anharmonic. While the agreement between theory and experiment is useful for assignment, quantitative discrepancies still remain due to the deficiency of MP2 theory to describe the highly anharmonic surface. (C) 2000 Elsevier Science B.V. All rights reserved.
The effects of the social environment and age on juvenile hormone (JH) and reproduction were investigated by measuring ovarian development, hemolymph levels of JH III, and rates of JH biosynthesis from the same individual bumble bees (Bombus terrestris). Differences in social environment were associated with differences in rates of JH biosynthesis, JH titer and ovarian development. Young queenless workers had a higher rate of JH biosynthesis, JH titer and ovarian development than queenright (QR) workers of similar age. Dominant workers in QR colonies had a higher rate of JH biosynthesis, JH titer and ovarian development than low ranked workers of similar size. There was a positive correlation between JH titer and ovarian development, but no correlation between rate of JH biosynthesis and ovarian development or between JH biosynthesis and JH titer. Both JH titer and rate of JH biosynthesis increased with age from emergence to 3 days of age, but 6-day-old workers, egg-laying workers, and actively reproducing queens had high JH titers and highly developed ovaries but low rates of JH biosynthesis. These results show that reproduction in B. terrestris is strongly affected by the social environment and the influence of the environment on reproduction is mediated by JH. Our data also indicate that the rate of JH biosynthesis measured in vitro is not a reliable indicator of JH titer or ovarian development in B. terrestris; possible reasons are discussed. (C) 1999 Elsevier Science Ltd. All rights reserved.
Revised and reprinted, along with the translation (by N. Strazhas) of Shalamov's "The Artist of the Spade" in Towards the Ethics of Form in Fiction. Columbus: Ohio State University Press, 2010, pp. 179-190 and 191-201.
The dynamics of the K + CH3I reaction is discussed with special reference to two factors that govern the electron transfer. One is that at higher collision velocity the behavior need not be adiabatic so that there can be a finite probability for the electron not to transfer, resulting in no reaction. The other is the marked increase of the electron affinity of CH3I with its bond extension. The electron transfer can therefore take place at much larger separation of the reactants if CH3I is stretched. The barrier to reaction is then much lower. These observations are used to discuss the stereodynamics of the reaction. Several open problems are identified.
An adiabatic-Floquet formalism is used to study the suppression of ionization in short laser pulses. In the high-frequency limit the adiabatic equations involve only the pulse envelope where transitions are purely ramp effects. For a short-ranged potential having a single-bound state we show that ionization suppression is caused by the appearance of a laser-induced resonance state, which is coupled by the pulse ramp to the ground state and acts to trap ionizing flux.
Reviews the book 'Les nouveaux-juifs d'Amsterdam. Essais sur l'histoire sociale et intellectuelle du judaisme sefarade au XVIIe siecle,' by Yosef Kaplan.
The adsorption free energy of charged proteins on mixed membranes, containing varying amounts of (oppositely) charged lipids, is calculated based on a mean-field free energy expression that accounts explicitly for the ability of the lipids to demix locally, and for lateral interactions between the adsorbed proteins. Minimization of this free energy functional yields the familiar nonlinear Poisson-Boltzmann equation and the boundary condition at the membrane surface that allows for lipid charge rearrangement. These two self-consistent equations are solved simultaneously. The proteins are modeled as uniformly charged spheres and the (bare) membrane as an ideal two-dimensional binary mixture of charged and neutral lipids. Substantial variations in the lipid charge density profiles are found when highly charged proteins adsorb on weakly charged membranes; the lipids, at a certain demixing entropy penalty, adjust their concentration in the vicinity of the adsorbed protein to achieve optimal charge matching. Lateral repulsive interactions between the adsorbed proteins affect the lipid modulation profile and, at high densities, result in substantial lowering of the binding energy. Adsorption isotherms demonstrating the importance of lipid mobility and protein-protein interactions are calculated using an adsorption equation with a coverage-dependent binding constant. Typically, at bulk-surface equilibrium (i.e., when the membrane surface is ``saturated'' by adsorbed proteins), the membrane charges are ``overcompensated'' by the protein charges, because only about half of the protein charges (those on the hemispheres facing the membrane) are involved in charge neutralization. Finally, it is argued that the formation of lipid-protein domains may be enhanced by electrostatic adsorption of proteins, but its origin (e.g., elastic deformations associated with lipid demixing) is not purely electrostatic.
