Search for the decay upsilon(1S) --> gammaeta(')

We report on a search for the radiative decay Upsilon(1S)-->gammaeta(') in 61.3 pb(-1) of data taken with the CLEO II detector at the Cornell Electron Storage Ring. Three decay chains were investigated, all involving eta(')-->pi(+)pi(-)eta, followed by eta-->gammagamma, eta-->pi(0)pi(0)pi(0), or eta-->pi(+)pi(-)pi(0). We find no candidate events in any of the three cases and set a combined upper limit of 1.6x10(-5) at 90% C.L., significantly smaller than the previous limit. We compare our result to other radiative Upsilon decays, to radiative J/psi decays, and to theoretical predictions.     

Non-Globular Organic Ionic Plastic Crystal Containing a Crown-Ether Moiety – Tuning Its Behaviour Using Sodium Salts

Organic ionic plastic crystals (OIPCs) are a class of soft materials showing positional order while still allowing orientational freedom. Due to their motional freedom in the solid state, they possess plasticity, non-flammability and high ionic conductivity. OIPC behavior is typically exhibited by ‘simple’ globular molecules allowing molecular rotation, whereas the interactions that govern the formation of OIPC phases in complex non-globular molecules are less understood. To better understand these interactions, a new family of non-globular OIPCs containing a 15-crown-5 ether moiety was synthetized and characterized. The 15C5BA molecule prepared does not exhibit the sought-after behavior because of its non-globular nature and strong intermolecular H-bonds that restrict orientational motion. However, the OIPC behavior was successfully obtained through complexation of the crown-ether moiety with sodium salts containing chaotropic anions. Those anions weaken the interactions between the molecules, allowing rotational freedom and tuning of the thermal and morphological properties of the OIPC.     

The copolymerization of carbon dioxide and [2-(3,4-epoxycyclohexyl)ethyl]trimethoxysilane catalyzed by (salen)CrCl. Formation of a CO2 soluble polycarbonate

The copolymerization of 2-(3,4-epoxycyclohexyl)ethyl-trimethoxysilane and carbon dioxide catalyzed by (salen)Cr(III)Cl (H(2)salen = N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-ethylenediimine) with 2.5 equiv of N-MeIm as cocatalyst affords a polycarbonate devoid of polyether linkages, along with only a trace quantity of cyclic carbonate. The presence of the trimethoxysilane functionality in the epoxide not only provided the reactant monomer and product copolymer high solubility in liquid carbon dioxide but also provided the ability to cross-link the copolymer and thereby greatly alter the physical properties of the thus formed polycarbonate. In addition, the enhanced solubility of the copolymer in liquid CO(2) furnishes a ready means of removing the highly colored metal catalyst from the polycarbonate product.     

Dielectrophoresis-based programmable fluidic processors

Droplet-based programmable processors promise to offer solutions to a wide range of applications in which chemical and biological analysis and/or small-scale synthesis are required, suggesting they will become the microfluidic equivalents of microprocessors by offering off-the-shelf solutions for almost any fluid based analysis or small scale synthesis problem. A general purpose droplet processor should be able to manipulate droplets of different compositions (including those that are electrically conductive or insulating and those of polar or non-polar nature), to control reagent titrations accurately, and to remain free of contamination and carry over on its reaction surfaces. In this article we discuss the application of dielectrophoresis to droplet based processors and demonstrate that it can provide the means for accurately titrating, moving and mixing polar or non-polar droplets whether they are electrically conductive or not. DEP does not require contact with control surfaces and several strategies for minimizing surface contact are presented. As an example of a DEP actuated general purpose droplet processor, we show an embodiment based on a scaleable CMOS architecture that uses DEP manipulation on a 32 x 32 electrode array having built-in control and switching circuitry. Lastly, we demonstrate the concept of a general-purpose programming environment that facilitates droplet software development for any type of droplet processor.     

Observation of the decay Omega(0)(c)-->Omega(-)e(+)nu(e)

Using the CLEO detector at the Cornell Electron Storage Ring we have observed the Omega(0)(c) (css ground state) in the decay Omega(0)(c)-->Omega(-)e(+)nu(e). We find a signal of 11.4+/-3.8(stat) events. The probability that we have observed a background fluctuation is 7.6x10(-5). We measure B(Omega(0)(c)-->Omega(-)e(+)nu(e)).sigma(e(+)e(-)-->Omega(0)(c)X)=(42.2+/-14.1(stat)+/-5.7(syst)) fb and R=[Gamma(Omega(0)(c)-->Omega(-)pi(+))]/[Gamma(Omega(0)(c)-->Omega(-)enu(e))]=00.41+/-0.19(stat)+/-0.04(syst). This is the first statistically significant observation of an individual decay mode of the Omega(0)(c) in e(+)e(-) annihilation and the first example of a baryon decaying via beta emission, where no quarks from the first generation participate in the reaction.     

Stereospecific analytical method development and preliminary in vivo pharmacokinetic characterization of pinostrobin in the rat

The complete pharmacokinetic disposition of the chiral flavonoid (±) pinostrobin remains unknown without the development of an analytical method of detection and quantitation of its individual enantiomers. Resolution of the enantiomers of pinostrobin was achieved using as simple high‐performance liquid chromatographic method. A Chiralpak® AD‐RH column was employed to perform baseline separation with UV detection at 287 nm. The standard curves were linear ranging from 0.5 to 100 µg/mL for each enantiomer. The limit of quantification was 0.5 µg/mL. Precision and accuracy of the assay was < 15% (RSD) and was with a bias <15% for all points on the calibration curve. The assay was applied successfully to stereoselective serum disposition of pinostrobin enantiomers in rats. Both enantiomers had a serum half‐life of ~7 h. They also shared similar values of volume of distribution (V_d S‐pinostrobin, 8.2 L/kg; V_d R‐pinostrobin, 8.9 L/kg), total clearance (S‐pinostrobin CL_total, 0.959 L//h/kg; R‐pinostrobin CL_total, 1.055 L//h/kg), and area under the curve (S‐pinostrobin AUC_inf, 23.16 µg h/mL; R‐pinostrobin AUC_inf, 21.296 µg h/mL). The large volume of distribution suggests extensive distribution of pinostrobin into tissues. Copyright © 2012 John Wiley & Sons, Ltd.     

Study of enantioselectivity on an immobilized amylose carbamate stationary phase under subcritical fluid chromatography

In this paper, we describe the enantiomeric separation of a chiral alcohol under subcritical fluid chromatography conditions using a 3 μm particle size bonded amylose carbamate stationary phase. Linear and branched alcohols were used as polar modifiers in CO₂. The studies with linear alcohols showed a decrease in selectivity factor as the number of carbons in the linear chain increased. For branched alcohols, as the bulk of substituents at the α carbon atom increases the separation factor decreases. Thermodynamic studies showed that in the presence of the alcohols studies, except methanol and ethanol, a positive ΔΔS was observed. Molecular mechanics simulation brought more insights into the mechanism of enantiomeric separation on this stationary phase under subcritical fluid chromatography.     

Detection of Al(III) and Ga(III) complexes with morin by electrospray ionization mass spectrometry.

The Al(III) and Ga(III) complexes formed by morin (M) in aqueous solution were investigated by means of electrospray ionization mass spectrometry (ESI-MS). In the full scan mass spectra, Al:M showed 1:2 and 2:3 stoichiometric ratios. When (S)-N-acetylserine methyl ester (Ser), as a partial mimic of the serine residue in silk, was added to Al:M and Ga:M complexes in aqueous solution, the mass spectra of Ser:Al:M showed 1:1:1 and 1:1:2 stoichiometric ratios. The patterns of the mass spectra of Ga:M and Ser:Ga:M complexes were similar to those for the corresponding Al(III) complexes. Calculated heats of formation of potential structures of the complexes, with and without bound water, were obtained using semiempirical PM3 calculations.