Observation of a new DsJ meson in B+-->D0D0K+ decays

We report the observation of a new DsJ meson produced in B+-->D0DsJ-->D0D0K+. This state has a mass of M=2708+/-9(-10)(+11) MeV/c2, a width Gamma=108+/-23(-31)(+36) MeV/c2 and a 1- spin-parity. The statistical significance of this observation is 8.4 sigma. The results are based on an analysis of 449 x 10(6) BB events collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider.     

Synthesis, spectroscopy, and X-ray structures of fac-(CO)3(dppe)MnSC(S)H, fac-(CO)3(dppe)ReSC(S)H, fac-(CO)3(dppp)ReSC(S)H, and fac-(CO)3(dppb)ReSC(S)H

The monodentate dithioformato complexes, fac-(CO)₃(dppe)MnSC(S)H (1), fac- (CO)₃(dppe)ReSC(S)H (2), fac-(CO)₃(dppp)ReSC(S)H (3), and fac-(CO)₃ (dppb)ReSC(S)H (4), where dppe is 1,2-bis(diphenylphosphino)ethane, dppp is 1,3-bis(diphenylphosphino)propane, and dppb is 1,4-bis(diphenylphosphino)butane, were synthesized from the treatment of the corresponding hydrides, fac-(CO)₃ (P-P)MSC(S)H with CS₂. Compounds 1–4 crystallize in the monoclinic crystal system: for 1, space group = P2₁/c, a = 15.3139(3) Å, b = 9.7297(4) Å, c = 19.0991(6) Å, = 105.928(1), V = 2736.5 ų, Z = 4; for 2, space group = P2₁/c, a = 15.6395(8) Å, b = 9.8182(5) Å, c = 19.4153(11) Å, = 106.741(1), V = 2854.9(3) ų, Z = 4; for 3, space group = P2₁/n, a = 11.3570(10) Å, b = 19.465(2) Å, c = 15.5702(14) Å, = 104.776(2), V = 3328.3(5) ų, Z = 4; and for 4, space group = C2/c, a = 32.078(2) Å, b = 10.4741(6) Å, c = 19.0608(9) Å, = 94.315(2), V = 6386.1(6) ų, Z = 8.     

Stabilization of Catalytically Active Cu+ Surface Sites on Titanium–Copper Mixed‐Oxide Films

The oxidation of CO is the archetypal heterogeneous catalytic reaction and plays a central role in the advancement of fundamental studies, the control of automobile emissions, and industrial oxidation reactions. Copper‐based catalysts were the first catalysts that were reported to enable the oxidation of CO at room temperature, but a lack of stability at the elevated reaction temperatures that are used in automobile catalytic converters, in particular the loss of the most reactive Cu⁺ cations, leads to their deactivation. Using a combined experimental and theoretical approach, it is shown how the incorporation of titanium cations in a Cu₂O film leads to the formation of a stable mixed‐metal oxide with a Cu⁺ terminated surface that is highly active for CO oxidation.     

Integrated Adsorption–Photodegradation of Organic Pollutants by Carbon Xerogel/Titania Composites

Recent studies on the removal of pollutants via adsorption include the use of carbon-based adsorbents, due to their high porosity and large surface area; however, such materials lack photoactive properties. This study evaluates the synergistic effect of integrated mesoporous carbon xerogel (derived from resorcinol formaldehyde) and titanium dioxide (TiO₂) for combined adsorption and photodegradation application. The complex formed between carbon xerogel and TiO₂ phase was investigated through FTIR, proving the presence of a Ti-O–C chemical linkage. The physicochemical properties of the synthesised adsorbent–photocatalyst were probed using FESEM, BET analysis and UV–Vis analysis. The kinetics, equilibrium adsorption, effect of pH, and effect of adsorbent dosage were investigated. The expansion of the absorbance range to the visible range was verified, and the corresponding band gap evaluated. These properties enabled a visible light response when the system was exposed to visible light post adsorption. Hence, an assistive adsorption–photodegradation phenomenon was successfully executed. The adsorption performance exhibited 85% dye degradation which improved to 99% following photodegradation. Further experiments showed the reduction of microorganisms under visible light, where no microbial colonies were observed after treatment, indicating the potential application of these composite materials.     

Multistability,intermittency and remerging Feigenbaum trees in an externally pumped ring cavity laser system

We study a Fabry-Pérot cavity containing a saturable absorber and driven by an external laser. It is shown that the output field as a function of the input field and bistability parameter exhibits multistability, intermittency and remerging Feigenbaum trees.     

Rheological complexity in simple chain models

Dynamical properties of short freely jointed and freely rotating chains are studied using molecular dynamics simulations. These results are combined with those of previous studies, and the degree of rheological complexity of the two models is assessed. New results are based on an improved analysis procedure of the rotational relaxation of the second Legendre polynomials of the end-to-end vector in terms of the Kohlrausch-Williams-Watts (KWW) function. Increased accuracy permits the variation of the KWW stretching exponent beta to be tracked over a wide range of state points. The smoothness of beta as a function of packing fraction eta is a testimony both to the accuracy of the analytical methods and the appropriateness of (eta(0)-eta) as a measure of the distance to the ideal glass transition at eta(0). Relatively direct comparison is made with experiment by viewing beta as a function of the KWW relaxation time tau(KWW). The simulation results are found to be typical of small molecular glass formers. Several manifestations of rheological complexity are considered. First, the proportionality of alpha-relaxation times is explored by the comparison of translational to rotational motion (i.e., the Debye-Stokes-Einstein relation), of motion on different length scales (i.e., the Stokes-Einstein relation), and of rotational motion at intermediate times to that at long time. Second, the range of time-temperature superposition master curve behavior is assessed. Third, the variation of beta across state points is tracked. Although no particulate model of a liquid is rigorously rheologically simple, we find freely jointed chains closely approximated this idealization, while freely rotating chains display distinctly complex dynamical features.     

Synthesis of novel indenoquinolines and indenopyridazines via photoisomerization of benzotropolone derivatives

We describe the photoisomerization of hetero Diels-Alder adducts of tetramethylpurpurogallin bearing β,γ-unsaturated ketone chromophores and endocyclic -N-O- or -N-N- groups. Based on spectroscopic and crystallographic data, our results indicate that the outcome of the reaction for the two types of substrates can be correlated with the difference in the stabilities of the radical intermediates generated in each case. For oxazines, the photoisomerization involves both the β,γ-unsaturated ketone and -N-O- moieties, and proceeds through the formation of allyl, benzoyl, phenyl, and α-carbonyl radical intermediates. While the same allylic and benzoyl radicals are formed in adducts with an -N-N- group, the hydrazine does not participate in the reaction and the product is a simple rearrangement of the initial intermediate.     

High-capacity hydrogen and nitric oxide adsorption and storage in a metal-organic framework

Gas adsorption experiments have been carried out on a copper benzene tricarboxylate metal-organic framework material, HKUST-1. Hydrogen adsorption at 1 and 10 bar (both 77 K) gives an adsorption capacity of 11.16 mmol H2 per g of HKUST-1 (22.7 mg g(-)1, 2.27 wt %) at 1 bar and 18 mmol per g (36.28 mg g(-)1, 3.6 wt %) at 10 bar. Adsorption of D2 at 1 bar (77 K) is between 1.09 (at 1 bar) and 1.20(at <100 mbar) times the H2 values depending on the pressure, agreeing with the theoretical expectations. Gravimetric adsorption measurements of NO on HKUST-1 at 196 K (1 bar) gives a large adsorption capacity of approximately 9 mmol g(-1), which is significantly greater than any other adsorption capacity reported on a porous solid. At 298 K the adsorption capacity at 1 bar is just over 3 mmol g(-1). Infra red experiments show that the NO binds to the empty copper metal sites in HKUST-1. Chemiluminescence and platelet aggregometry experiments indicate that the amount of NO recovered on exposure of the resulting complex to water is enough to be biologically active, completely inhibiting platelet aggregation in platelet rich plasma.