An acyclic phane receptor with a pair of disulfonaphthalene arms recognizing 2,3-trans-gallate-type catechins in water

In order to develop a receptor molecule for recognizing differences in catechin structures, complexation between catechins and a water-soluble acyclic phane composed of an isophthalate and two aminodisulfonaphthalenes was investigated with ¹H NMR spectroscopy. The phane receptor formed 1:1 complexes with the catechins and showed preferential binding ability for the 2,3-trans-gallate-type catechin. The binding studies demonstrated the length of naphthalene framework required to form a hydrophobic environment for the complexation.     

Lewis acid-catalyzed intramolecular amination via 1,3-chirality transfer

Direct intramolecular amination of the chiral non-racemic allylic alcohol 1 conjugated with a benzene ring afforded the tetrahydroisoquinoline 2 possessing a newly formed alkene in the presence of a catalytic amount of Lewis acid.     

Amperometric determination of choline with enzyme immobilized in a hybrid mesoporous membrane

Choline sensor is successfully prepared by using immobilized enzyme, i.e., choline oxidase (ChOx) within a hybrid mesoporous membrane with 12 nm pore diameter (F127M). The measurement was based on the detection of hydrogen peroxide, which is the co-product of the enzymatic choline oxidation. The determination range and the response time are 5.0-800 μM and approximately 2 min, respectively. The sensor is very stable compared to the native enzyme sensor and 85% of the initial response was maintained even after storage for 80 days. These results indicate that ChOx is successfully immobilized and well stabilized, and at the same time, enzyme reaction proceeds efficiently. Such ability of hybrid mesoporous membrane F127M suggests great promise for effective immobilization of enzyme useful for electrochemical biosensors.     

Remark on Single Exponential Bound of the Vorticity Gradient for the Two-Dimensional Euler Flow Around a Corner

In this paper, we consider the two–dimensional Euler flow under a simple symmetry condition, with hyperbolic structure in a unit square \({D = \{(x_1,x_2):0 < x_1+x_2 < \sqrt{2},0 < -x_1+x_2 < \sqrt{2}\}}\). It is shown that the Lipschitz estimate of the vorticity on the boundary is at most a single exponential growth near the stagnation point.     

Storage of multiple coherent microwave excitations in an electron spin ensemble

Strong coupling between a microwave photon and electron spins, which could enable a long-lived quantum memory element for superconducting qubits, is possible using a large ensemble of spins. This represents an inefficient use of resources unless multiple photons, or qubits, can be orthogonally stored and retrieved. Here we employ holographic techniques to realize a coherent memory using a pulsed magnetic field gradient and demonstrate the storage and retrieval of up to 100 weak 10?GHz coherent excitations in collective states of an electron spin ensemble. We further show that such collective excitations in the electron spin can then be stored in nuclear spin states, which offer coherence times in excess of seconds.     

Demonstration of local expansion toward large-scale entangled webs

We demonstrate an optical gate that increases the size of polarization-based W states by accessing only one of the qubits. Using this gate, we have generated three-photon and four-photon W states with fidelities 0.836 ± 0.042 and 0.784 ± 0.028, respectively. We also confirmed the existence of pairwise entanglement in every pair of qubits, including the one that was left untouched by the gate. The gate is applicable to any size of W states and hence is a universal tool for expanding entanglement.     

Perfect softening of the ferroelectric mode in the isotope-exchanged strontium titanate of SrTi18O3 studied by light scattering

The mode of the isotope-induced ferroelectric strontium titanate shows a perfect softening at the ferroelectric phase transition temperature , where the frequency of the underdamped mode approaches completely to zero within the instrumental resolution. The spectra of the Raman inactive soft mode have been successfully observed owing to local symmetry breaking and by long-term accumulation of the spectral intensity with a high resolution technique. The mechanism of the phase transition is concluded to be an ideal displacive-type accompanied with perfect softening of the Slater-type polar mode. The difference between the soft mode behavior of and indicates that the origin of the quantum paraelectric state of lies in the quantum fluctuation of the oxide octahedron in the perovskite structure.     

Observation of b-->dgamma and determination of /Vtd/Vts/

We report the observation of the flavor-changing neutral current process b-->dgamma using a sample of 386 x 106 B meson pairs accumulated by the Belle detector at the KEKB e+e- collider. We measure branching fractions for the exclusive modes B--->rho-gamma, B0rho0gamma, and B0omegagamma. Assuming that these three modes are related by isospin, we find B(B-->(rho,gamma)gamma)=[Formula: See Text] with a significance of 5.1sigma. This result is used to determine the ratio of Cabibbo-Kobayashi-Maskawa matrix elements /Vtd/Vts/ to be [Formula: See Text].     

Gas‐phase basicities of acetophenones toward lanthanum cation [La(OMe)]

The relative free energy changes (lanthanum cation basicity, LaCB[L₂]) for the reaction [La(OMe)₂]L ? La(OMe) + 2L were determined in the gas phase for m‐ and p‐substituted acetophenones based on the measurement of ligand exchange equilibria using an FT‐ICR mass spectrometer. The substituent effect on ΔLaCB[L₂] of acetophenone is described in terms of the Yukawa–Tsuno equation, ΔG = ρ(σ° + r⁺ Δ σ ), with a ρ value of ?11.2 and an r⁺ value of 0.49. From this result, a ρ value of ?7.0 and an r⁺ value of 0.49 were estimated for the monomeric complex [LLa(OMe)] with the aid of theoretical calculations. This ρ value was found to be significantly smaller than that for protonation, and even smaller than Li⁺ basicity. Such a small ρ value has been attributed to the largely ionic (ion–dipole interaction) nature of the bonding interaction between La(OMe) and the carbonyl oxygen atom and, in part, to the long distance between La(OMe) and the substituent. Contrary to the ρ value, the r⁺ value is identical in both La(OMe) and Li⁺ basicities, suggesting that the r⁺ value of 0.49 can be regarded as a limiting one in a series of Lewis cation basicities of the acetophenone system, H⁺ (0.86) > Me₃Si⁺ (0.75) > Me₃Ge⁺ (0.71) > Cu⁺ (0.60) > Li⁺ = La(OMe) (0.49). Since the binding interaction between La(OMe) or Li⁺ and a neutral ligand is mostly electrostatic, the moderate r⁺ was interpreted to result from the redistribution of the induced positive charge within the acetophenone moiety upon binding with a metal ion rather than transfer of positive charge from a metal ion to the aromatic moiety. Copyright © 2010 John Wiley & Sons, Ltd.