Measurement of branching fractions and mass spectra of B-->Kpipigamma

We present a measurement of the partial branching fractions and mass spectra of the exclusive radiative penguin processes B-->Kpipigamma in the range m(Kpipi)<1.8 GeV/c(2). We reconstruct four final states: K(+)pi(-)pi(+)gamma, K(+)pi(-)pi(0)gamma, K(S)(0)pi(-)pi(+)gamma, and K(S)(0)pi(+)pi(0)gamma, where K(S)(0)-->pi(+)pi(-). Using 232 x 10(6) e(+)e(-)-->BB events recorded by the BABAR experiment at the SLAC PEP-II asymmetric-energy storage ring, we measure the branching fractions B(B(+)-->K(+)pi(-)pi(+)gamma)=[2.95+/-0.13(stat)+/-0.20(syst)] x 10(-5), B(B(0)-->K(+)pi(-)pi(0)gamma)=[4.07+/-0.22(stat)+/-0.31(syst)] x 10(-5), B(B(0)-->K(0)pi(+)pi(-)gamma)=[1.85+/-0.21(stat)+/-0.12(syst)] x 10(-5), and B(B(+)-->K(0)pi(+)pi(0)gamma)=[4.56+/-0.42(stat)+/-0.31(syst)] x 10(-5).     

Observation of B Meson decays to b1pi and b1K

We present the results of searches for decays of B mesons to final states with a b1 meson and a charged pion or kaon. The data, collected with the BABAR detector at the Stanford Linear Accelerator Center, represent 382x10(6) BB[over ] pairs produced in e+e- annihilation. The results for the branching fractions are, in units of 10(-6), B(B+-->b1(0)pi+)=6.7+/-1.7+/-1.0, B(B+-->b1(0)K+)=9.1+/-1.7+/-1.0, B(B0-->b1(-/+)pi(+/-))=10.9+/-1.2+/-0.9, and B(B0-->b1(-)K+)=7.4+/-1.0+/-1.0, with the assumption that B(b1-->omega pi)=1. We also measure charge and flavor asymmetries A(ch)(B+-->b1(0)pi+)=0.05+/-0.16+/-0.02, Ach(B+-->b1(0)K+)=-0.46+/-0.20+/-0.02, A(ch)(B0-->b1(-/+)pi(+/-))=-0.05+/-0.10+/-0.02, C(B0-->b1(-/+)pi(+/-))=-0.22+/-0.23+/-0.05, DeltaC(B0-->b1(-/+)pi(+/-))=-1.04+/-0.23+/-0.08, and A(ch)(B0-->b1(-)K+)=-0.07+/-0.12+/-0.02. The first error quoted is statistical, and the second systematic.     

Synthesis of 6-substituted-4-hydroxy-2-pyridinones via intramolecular ketene trapping of functionalized enamine-dioxinones

The synthesis of various 6-substituted-4-hydroxy-2-pyridinones is reported. The functionalized keto-dioxinones were constructed via a diethylzinc mediated crossed Claisen condensation reaction and subsequent enamine formation, thermolysis, and cyclization-aromatization providing the pyridinone unit.     

Biomimetic total synthesis of angelicoin A and B via a palladium-catalyzed decarboxylative prenylation-aromatization sequence

Five-step total syntheses of angelicoin A and B from 2,2,6-trimethyl-4-dioxinone are reported using late stage biomimetic aromatization reactions via diketo-dioxinones as intermediates. In addition, with angelicoin A, this aromatization was coupled with a palladium-catalyzed decarboxylative prenylation in a one-pot sequence as the key step.     

Dendritic cell internalization of foam-structured fluorescent mesoporous silica nanoparticles

In this paper, foam-structured fluorescent mesoporous silica nanoparticles (FMSNs) are produced in a sol-gel method with the introduction of a phosphonate functional group. It is found that the phosphonate functionalized FMSNs with the foam structure minimizes the aggregation of FMSNs in solution. The average particle size of the FMSNs without and with phosphonate functionalization is 46.3 ± 5 nm and 60.5 ± 8 nm in diameter, respectively. The latter one exhibits higher fluorophore loading capacity (~67 ± 2.5%). The excitation wavelength (λ(ex)) of FMSNs is observed at 526 nm, approximate 12 nm larger in the Stoke-shift compared to the free organic dye at 494/514 nm. Furthermore, the photostability of the hydrophobic fluorophore is greatly improved by the FMSNs with the foam structure. In addition, the dose-dependent nature of FMSN uptake is assessed for the immune cells, the bone marrow-derived dendritic immune cells (BMDCs). Our results indicate that approximately 42% of BMDCs are able to take up foam-structured FMSNs (>5 μg/ml) without decreasing the viability of BMDCs. Thus, the phosphonate functionalized FMSNs with the foam structure are suitable to be used for many biomedical applications, especially in cell tracking.     

Separation of parasites from human blood using deterministic lateral displacement

We present the use of a simple microfluidic technique to separate living parasites from human blood. Parasitic trypanosomatids cause a range of human and animal diseases. African trypanosomes, responsible for human African trypanosomiasis (sleeping sickness), live free in the blood and other tissue fluids. Diagnosis relies on detection and due to their often low numbers against an overwhelming background of predominantly red blood cells it is crucial to separate the parasites from the blood. By modifying the method of deterministic lateral displacement, confining parasites and red blood cells in channels of optimized depth which accentuates morphological differences, we were able to achieve separation thus offering a potential route to diagnostics.     

Novel structural phases of Dy thin films on W(1 1 2)

Thin films of the rare-earth metal Dy were grown on W(1 1 2) at room temperature and 570 K. Then the resultant film morphologies were characterised by LEED and STM. A series of novel film morphologies, including c(4 × 6), c(5 × 12) and (5 × 8) structures, were found that are unique among the rare-earth metals. High thermal stability was found for the Dy films (up to 1650 K, close to the melting point at 1685 K) such that the Dy atoms preserved an ordered structure and the Dy volatility was less than would be expected from its vapour pressure. This is an indication of strong electronic interactions between the Dy atoms and the W(1 1 2) substrate.     

ROMPgel-supported tris(triphenylphosphine)rhodium(I) chloride: a selective hydrogenation catalyst for parallel synthesis

ROMPgel-supported tris(triphenylphosphine)rhodium(I) chloride has been prepared and the immobilised catalyst has been effectively employed in selective hydrogenations of a variety of alkenes and terminal alkynes.     

The role of optimum dielectric saturation in the reversible combination of oxygen with heme Fe2+ and the tuning of paramagnetic-diamagnetic switching

The paramagnetic-diamagnetic switching mechanism of hemoglobin, triggered by oxygen binding, is studied by a formalism involving an expression of work necessary to polarize the dielectric in Landau form. The “tuning” of the mechanism, or determination of occurrence of the switching in response to a certain input energy, is brought about by dielectric saturation of the medium. The relation between the effect of dielectric saturation of the medium and the effect of application of a constant (nonordering) magnetic field indicates charge transfer between the central Fe²⁺ ion and the porphyrin ring during switching.