A more sensitive MS detector does not obviously lead to a more sensitive assay: experiences with ES-285

In this paper the transfer of an existing method for the quantitative determination of the anticancer agent ES-285 in human plasma using liquid chromatography tandem mass spectrometry on an API 365 to an API 3000 mass spectrometer is described. The transfer appeared not to be straightforward. Problems arose resulting from carry-over and interferences. In addition, due to the expansion of the calibration range, data ought to be weighted with a different factor to increase the accuracy of the lower concentrations. After finding appropriate solutions for these problems, the lower limit of quantitation could be lowered from 10 to 1 ng/mL for ES-285 in human plasma. The usefulness and necessity of the modified assay was demonstrated by analysis of plasma samples from a patient receiving a low dosage of the drug.     

A general approach to detect protein expression in vivo using fluorescent puromycin conjugates

Understanding the expression of known and unknown gene products represents one of the key challenges in the post-genomic world. Here, we have developed a new class of reagents to examine protein expression in vivo that does not require transfection, radiolabeling, or the prior choice of a candidate gene. To do this, we constructed a series of puromycin conjugates bearing various fluorescent and biotin moieties. These compounds are readily incorporated into expressed protein products in cell lysates in vitro and efficiently cross cell membranes to function in protein synthesis in vivo as indicated by flow cytometry, selective enrichment studies, and Western analysis. Overall, this work demonstrates that fluorescent-puromycin conjugates offer a general means to examine protein expression in vivo.     

A charge-transfer-induced spin transition in the discrete cyanide-bridged complex [[Co(tmphen)2]3[Fe(CN)6]2

A charge-transfer-induced spin transition (CTIST) is observed in the discrete cyanide-bridged complex, {[Co(tmphen)2]3[Fe(CN)6]2}. Single-crystal X-ray diffraction, 57Fe M?ssbauer spectroscopy, and magnetic susceptibility were used collectively to describe the oxidation states of the Co and Fe ions in this cluster as a function of temperature. This pentanuclear complex represents the first example of a CTIST at the discrete molecular level.     

New reactions in water: metal-free conversion of alcohols and ketones into alpha-iodoketones

Using water as the reaction medium, ketones can be transformed into alpha-iodoketones upon treatment with sodium iodide, hydrogen peroxide and an acid; interestingly, alpha-iodoketones can be also obtained from secondary alcohols through a metal-free tandem oxidation-iodination approach.     

A new class of tethered-arene ruthenium(II) complexes with pendant P and C donor atoms: synthesis of eta6:eta1:eta1 phosphonio-azabutadienyl ruthenabicycles via allenylidene intermediates

The activation of 1,1-diphenyl-2-propyn-1-ol by complexes [RuCl(eta(6)-p-cymene)[eta(2)-P,N-Ph(2)PCH(2)P([=NR)Ph(2)]](+) results in the formation of the unusual tethered (eta(6)-arene)-ruthenium(ii) derivatives, via an unprecedented iminophosphorane-allenylidene coupling process.     

Edge-enhanced imaging with polyvinyl alcohol/acrylamide photopolymer gratings

We demonstrate edge-enhanced imaging produced by volume phase gratings recorded on a polyvinyl alcohol/acrylamide photopolymer. Bragg diffraction, exhibited by volume gratings, modifies the impulse response of the imaging system, facilitating spatial filtering operations with no need for a physical Fourier plane. We demonstrate that Kogelnik's coupled-wave theory can be used to calculate the transfer function for the transmitted and the diffracted orders. The experimental and simulated results agree, and they demonstrate the feasibility of our proposal.     

Spatial optical solitons supported by mutual focusing

We study composite spatial optical solitons supported by two-wave mutual focusing induced by cross-phase modulation in Kerr-like nonlinear media. We find the families of both single- and two-hump solitons and discuss their properties and stability. We also reveal remarkable similarities between recently predicted holographic solitons in photorefractive media and parametric solitons in quadratic nonlinear crystals.     

Resonant scattering of surface-plasmon polariton pulses by nanoscale metal defects

We have theoretically investigated the dynamics of the scattering of surface-plasmon polariton (SPP) pulses by single nanoscale metal defects through a rigorous calculation of the time dependence of the reflected and transmitted SPP and of the angular distribution of the scattered light. SPP resonances that occur at deep Gaussian grooves are probed with SPP pulses, the resonant scattering being unequivocally manifested by (a) the exponential tails of the scattered SPP and light pulses and (b) the delay time of the transmitted SPP pulse.     

Asymptotic properties of two interacting maps

In this paper we consider a system whose state x changes to (x) if a perturbation occurs at the time t, for . Moreover, the state x changes to the new state (x) at time t, for . It is assumed that the number of perturbations in an interval (0, t) is a Poisson process. Here and are measurable maps from a measure space into itself. We give conditions for the existence of a stationary distribution of the system when the maps and commute, and we prove that any stationary distribution is an invariant measure of these maps.     

Overcomplete Free Energy Functional for D = 1 Particle Systems with Next Neighbor Interactions

We deduce an overcomplete free energy functional for D=1 particle systems with next neighbor interactions, where the set of redundant variables are the local block densities _i of i interacting particles. The idea is to analyze the decomposition of a given pure system into blocks of i interacting particles by means of a mapping onto a hard rod mixture. This mapping uses the local activity of component i of the mixture to control the local association of i particles of the pure system. Thus it identifies the local particle density of component i of the mixture with the local block density _i of the given system. Consequently, our overcomplete free energy functional takes on the hard rod mixture form with the set of block densities _i representing the sequence of partition functions of the local aggregates of particle numbers i. The system of equations for the local particle density of the original system is closed via a subsidiary condition for the block densities in terms of . Analoguous to the uniform isothermal-isobaric technique, all our results are expressible in terms of effective pressures. We illustrate the theory with two standard examples, the adhesive interaction and the square-well potential. For the uniform case, our proof of such an overcomplete format is based on the exponential boundedness of the number of partitions of a positive integer (Hardy-Ramanujan formula) and on Varadhan's theorem on the asymptotics of a class of integrals.