Observation of B{0}-->ppK*0 with a large K*0 polarization

Using a 492 fb{-1} data sample collected near the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e{+}e{-} collider, we observe the decay B{0}-->ppK*0 with a branching fraction of (1.18{-0.25}{+0.29}(stat)+/-0.11(syst))x10{-6}. We study the decay dynamics of B{0}-->ppK*0 and compare with B{+}-->ppK*+. The K*0 meson is found to be almost 100% polarized (with a fraction of (101+/-13+/-3)% in the helicity zero state), while the K*+ meson has a (32+/-17+/-9)% fraction in the helicity zero state. The direct CP asymmetries for B{0}-->ppK*0 and B{+}-->ppK*+ are measured to be -0.08+/-0.20+/-0.02 and -0.01+/-0.19+/-0.02, respectively. In addition, we report improved measurements of the branching fractions B(B{+}-->ppK*+)=(3.38{-0.60}{+0.73}+/-0.39)x10{-6} and B(B{0}-->ppK{0})=(2.51{-0.29}{+0.35}+/-0.21)x10{-6}, which supersede our previous measurements.     

Novel carbon-carbon bond-forming reactions using carbocations produced from substituted propargyl silyl ethers by the action of TMSOTf.

Highly useful carbon-carbon bond forming reactions using stable allenyl, propargyl, or allyl-propargyl hybrid cations have been developed. These carbocations could be generated from silyl 1-(pi-donor)-substituted propargyl ethers by the action of trimethylsilyl trifluoromethanesulfonate in dichloromethane at -78 degrees C to room temperature and could be attacked nucleophilically by electron rich arenes, allylsilanes, or enol silyl ethers, giving rise to allenes, alkynes, and their derivatives. A novel method for regio- and stereoselective synthesis of conjugated enynes utilizing allyl-propargyl hybrid cations has also been established.     

Aromatization of enamines promoted by a stoichiometric amount of palladium(II) salts: a novel method for the synthesis of aromatic amines.

Enamines (1a-r) prepared from cyclohexanones, cyclohexane-1,3-diones, or tetralones led to arylamines (2a-r) in one pot when treated with a stoichiometric amount of palladium salts [PdCl2-(MeCN)2] in acetonitrile in the presence of triethylamine at room temperature or at elevated temperature, in some cases for 5 min to 2 h. The initial electrophilic attack of palladium chloride on the beta-carbon of the enamines led to a sigma-palladium species (8) which triggered a series of reactions (-->9-->10-->11-->12) destined for aromatization to give 2a-r in good yields. The intervention of such a sigma-palladium species has been attested by a trapping experiment. On the basis of this reaction mechanism, we have developed another new process capable of transforming acyclic compounds having 6-en-2-one frameworks (16, 23, 25) to arylamines (2s-u) when their enamines were treated under the similar conditions as above, featuring again the formation of sigma-palladium species such as 8 as the initial key intermediate.     

Complementarity Constraint Qualifications and Simplified B-Stationarity Conditions for Mathematical Programs with Equilibrium Constraints

With the aid of some novel complementarity constraint qualifications, we derive some simplified primal-dual characterizations of a B-stationary point for a mathematical program with complementarity constraints (MPEC). The approach is based on a locally equivalent piecewise formulation of such a program near a feasible point. The simplified results, which rely heavily on a careful dissection and improved understanding of the tangent cone of the feasible region of the program, bypass the combinatorial characterization that is intrinsic to B-stationarity.     

Biosorption of actinides from dilute waste actinide solution by egg-shell membrane

Removal of radioactive elements from the effluent and waste aqueous solutions is an important problem. In previous laboratory batch experiments, hen egg-shell membrane (ESM) was stable as an insoluble protein and was very capable of binding heavy metal ions from aqueous solution. Batch laboratory pH profile, time dependency, and capacity experiments were performed to determine the binding of uranium (U) and thorium (Th) to ESM. Batch pH profile experiments indicated that the optimum pH for binding these actinides was approx 6.0 (U) or 3.0 (Th). The adsorption isotherms were developed at pH 5.0 (U) or 3.0 (Th) at 25°C, and the adsorption equilibrium data fitted both Langmuir and Freundlich models. The maximum uptakes by the Langmuir model were about 240 mg U/g and 60 mg Th/g dry weight ESM. In addition, their adsorption capacities increased as salt concentration increased. ESM could also accumulate uranium from dilute aqueous solution by adjusting to the optimum pH. These results showed that ESM was effective for removing actinides from solution and would be useful in filtration technology to remove actinides from aqueous solution. S.-I. Ishikawa is a research fellow at the Japan Society for the Promotion of Science.     

Photochemistry of mesoionic compounds. Photochemical conversion of 5-azido-1,3-diaryltetrazolium salts to novel tricyclic mesoions with a tetrazolo[1,5-a]benzimidazole skeleton

A new type of tetrazolium-5-amide mesoions 2 with a tricyclic tetrazolo[1,5-a]benzimidazole skeleton has been synthesized via photolysis of 5-azido-1,3-diaryltetrazolium salts 1 .     

On the Structure of the Small Quantum Cohomology Rings of Projective Hypersurfaces

We give an explicit procedure which computes for degree d≤ 3 the correlation functions of topological sigma model (A-model) on a projective Fano hypersurface X as homogeneous polynomials of degree d in the correlation functions of degree 1 (number of lines). We extend this formalism to the case of Calabi–Yau hypersurfaces and explain how the polynomial property is preserved. Our key tool is the construction of universal recursive formulas which express the structure constants of the quantum cohomology ring of X as weighted homogeneous polynomial functions of the constants of the Fano hypersurface with the same degree and dimension one more. We propose some conjectures about the existence and the form of the recursive laws for the structure constants of rational curves of arbitrary degree. Our recursive formulas should yield the coefficients of the hypergeometric series used in the mirror calculation. Assuming the validity of the conjectures we find the recursive laws for rational curves of degree four. Received: 29 November 1996 / Accepted: 15 March 1999     

Ab initio molecular orbital study on the structures and energetics of CH3OH\documentclass{article}\pagestyle{empty}\begin{document}$_{2}^{+}$\end{document}(H2O)n and CH3SH\documentclass{article}\pagestyle{empty}\begin{document}$_{2}^{+}$\end{document}(H2O)n in the gas phase

The purpose of this study was to calculate the structures and energetics of CH₃OH$_{2}^{+}$(H₂O)_n and CH₃SH$_{2}^{+}$(H₂O)_n in the gas phase: we asked how the CH₃OH$_{2}^{+}$ and CH₃SH$_{2}^{+}$ moieties of CH₃OH$_{2}^{+}$(H₂O)_n and CH₃SH$_{2}^{+}$(H₂O)_n change with an increase in n and how can we reproduce the experimental values ΔH°_n−1,n. For this purpose, we carried out full geometry optimizations with MP2/6‐31+G(d,p) for CH₃OH$_{2}^{+}$(H₂O)_n (n=0,1,2,3,4,5) and CH₃SH$_{2}^{+}$(H₂O)_n (n=0,1,2,3,4). We also performed a vibrational analysis for all clusters in the optimized structures to confirm that all vibrational frequencies are real. All of the vibrational frequencies of these clusters are real, and they correspond to equilibrium structures. For CH₃OH$_{2}^{+}$(H₂O)_n, when n increases, (1) the C O bond length decreases, (2) the C H bond lengths do not change, (3) the O H bond lengths increase, (4) the OCH bond angles increase, (5) the COH bond angles decrease, (6) the charge on CH₃ becomes less positive, and (7) these predicted values, except for the O H bond lengths of CH₃OH$_{2}^{+}$(H₂O)_n, approach the corresponding values in CH₃OH. The C O bond length in CH₃OH$_{2}^{+}$(H₂O)₅ is shorter than that in CH₃OH$_{2}^{+}$ in the gas phase by 0.061 Å at the MP2/6‐31+G(d,p) level. Except for the S H bond lengths in CH₃SH$_{2}^{+}$(H₂O)_n, however, the structure of the CH₃SH$_{2}^{+}$ moiety does not change with an increase in n. © 2000 John Wiley & Sons, Inc. J Comput Chem 22: 125–131, 2001