A fluorescent assay for chloride transport; identification of a synthetic anionophore with improved activity

A fluorescent assay based on the chloride-sensitive probe, lucigenin, is developed for monitoring chloride transport into vesicles, and used to compare the effectiveness of three steroid-derived transporters.     

Passivation of Organic-Inorganic Hybrid Sol–Gel

A passivation method for improving long-term stability of organic-inorganic sol–gel material is reported. The effect is observed in experiments with two different passivation materials: Teflon AF and SiO₂. A regime of material curing prior to the passivation is found to strongly affect the optical loss. The degradation of waveguide loss with time due to moisture adsorption from the atmosphere is drastically suppressed by coating the material with a thin silica film. The results indicate a long-term optical loss below 0.3 dB/cm in coated waveguides, significantly smaller than that in uncoated waveguides. The mechanism of the loss reduction is described and experimentally confirmed.     

Investigation of alumina-supported Au catalyst for CO oxidation by isotopic transient analysis and X-ray absorption spectroscopy

Alumina-supported Au particles (1.16 wt %) were prepared by a deposition-precipitation method involving a HAuCl4 precursor. X-ray absorption spectroscopy at the Au L(III) edge was used to monitor the evolution of the Au oxidation state and atomic structure during pretreatment in He up to 623 K. Although the as-prepared material had Au present in a +3 oxidation state, thermal treatment at 623 K facilitated autoreduction of Au cations to metal particles. Analysis of the EXAFS revealed a coordination number (Au-Au) of 7.2, which is consistent with spherical particles of 1.2 nm in average diameter. Steady-state isotopic transient kinetic analysis was used to evaluate the intrinsic turnover frequency (TOF intr) and the surface coverage of carbon-containing species (theta COx) on the gold catalyst during CO oxidation at 1.2 atm total pressure and 296 K. The artifacts in the kinetic parameters caused by re-adsorption of product carbon dioxide were removed by varying the total flow rate. The values of TOF intr and theta COx determined from the intrinsic lifetime of surface intermediates at infinite flow rate were 1.6 s(-1) and 4.9%, respectively. The intrinsic turnover frequency was nearly independent of temperature, indicating a very low activation energy for the reaction. However, the rate was significantly accelerated by the presence of water.     

More Operator Versions of the Schwarz Inequality

Some new operator versions of the Schwarz inequality are obtained. One of them is a counterpart of the variance-covariance inequality in the context of noncommutative probability. Received: 14 April 2000 / Accepted: 10 May 2000     

Real-time queueing theory: A tutorial presentation with an admission control application

Real-time scheduling, or scheduling with respect to a deadline, is critical in many application areas such as telecommunications, control systems, and manufacturing. This paper presents a novel approach to real-time scheduling based on a queueing theory model. Using real-time queueing theory (RTQT), one can analytically determine the distribution of the lead-time profile (i.e., the time until the deadline is reached) of customers waiting for service. Emphasis is placed on the development of the equations used to determine the lead-time profile distribution. The development of the GI/G/1 case is presented and confirmed using simulation. Simulation results confirm prior research for the M/M/1 and GI/M/1 case. As a practical application, RTQT is used to implement a packet admission control algorithm for a telecommunications network. Using this algorithm, packet lateness was reduced by up to 31%. This revised version was published online in June 2006 with corrections to the Cover Date.     

Visual sensing of saccharides promoted by resorcinol condensation products

[structure: see text] Heating aqueous DMSO solutions of five saccharides in the presence of 1-3 reveals that each receptor promotes solution colors characteristic for each sugar. New compound 3 allows the direct correlation of sugar concentration with visible region absorbance and/or fluorescence intensities.     

A Family of Partial Difference Sets with Denniston Parameters in Nonelementary Abelian 2-Groups

We construct a family of partial difference sets with Denniston parameters in the groupZ₄^t × Z₂^tby using Galois rings.