Measurement of the e+e- -->pi+pi- J/psi cross section via initial-state radiation at Belle

The cross section for e(+)e(-)-->pi(+)pi(-)J/psi between 3.8 and 5.5 GeV/c(2) is measured using a 548 fb(-1) data sample collected on or near the Upsilon(4S) resonance with the Belle detector at KEKB. A peak near 4.25 GeV/c(2), corresponding to the so called Y(4260), is observed. In addition, there is another cluster of events at around 4.05 GeV/c(2). A fit using two interfering Breit-Wigner shapes describes the data better than one that uses only the Y(4260), especially for the lower-mass side of the 4.25 GeV enhancement.     

Conformational analysis of methyl 2-methyl-2-(1-naphthyl)propionate

(S)-2-Methoxy-2-(1-naphthyl)propionic acid (MαNP acid 1) is used for enantioseparation of many secondary alcohols and for determining the stereogenic centers. In the liquid state, based on the ¹H NMR anisotropy effect and reported results, it was shown that the MαNP ester preferred a coplanar relation between the methyl and naphthyl groups and a synperiplanar relation between the Cα-OMe and CO groups. In the case of 1,2,3,4-tetrahydro-4-phenanthrenol, which is a secondary alcohol, the stereogenic center was determined by X-ray analysis. It was shown that MαNP ester adopted similar arrangements in the solid state. However, it was presumed that the strong repulsion between oxygen atoms may be disadvantageous in the solid state. Therefore, we carried out conformational analysis using the simplest MαNP methyl ester to clarify this unique relationship. From detailed results based on the energy surface determined using the RHF/STO-3G basis set, the synperiplanar positional relation was the most stable, and the calculated results agreed with many reported experimental results. At the same time, all conformational isomers of the MαNP methyl ester were used to clarify the internal conversion pathways.     

Theoretical analysis on changes in thermodynamic quantities upon protein folding: essential role of hydration

The free energy change associated with the coil-to-native structural transition of protein G in aqueous solution is calculated by using the molecular theory of solvation, also known as the three-dimensional reference interaction site model theory, to uncover the molecular mechanism of protein folding. The free energy is decomposed into the protein intramolecular energy, the hydration energy, and the hydration entropy. The folding is accompanied with a large gain in the protein intramolecular energy. However, it is almost canceled by the correspondingly large loss in the hydration energy due to the dehydration, resulting in the total energy gain about an order of magnitude smaller than might occur in vacuum. The hydration entropy gain is found to be a substantial driving force in protein folding. It is comparable with or even larger than the total energy gain. The total energy gain coupled with the hydration entropy gain is capable of suppressing the conformational entropy loss in the folding. Based on careful analysis of the theoretical results, the authors present a challenging physical picture of protein folding where the overall folding process is driven by the water entropy effect.     

Hierarchical polymer assemblies constructed by the mutual template effect of cationic polymer complex and anionic supramolecular nanofiber

Creation of higher-ordered polymeric architectures composed of alternative assemblies of single-walled carbon nanotubes (SWNTs) and fibrous porphyrin J-aggregates can be easily achieved utilizing the cationic semi-artificial polysaccharide which can act not only as a tubular host for SWNTs but also as a one-dimensional template for porphyrin molecules. This new class of hierarchical polymer assembly is formed, for the first time, by the mutual template effect of two components, i.e., the cationic SWNT complexes and the anionic porphyrin supramolecular nanofibers. In the present system, the self-assembling behaviors of the SWNT complexes as well as the final properties of the SWNT nanoarchitectures are strongly affected by the packing mode of porphyrin molecules on the cationic semi-artificial polysaccharide. Furthermore, we have confirmed that the light energy captured by the porphyrin J-aggregates is effectively transferred to SWNTs.     

Preparations of polystyrene/aluminum hydroxide and polystyrene/alumina composite particles in an ionic liquid

Polystyrene (PS)/aluminum hydroxide (Al(OH)(3)) composite particles were successfully prepared by the sol-gel process of aluminum isopropoxide (Al(OPr(i))(3)) in a hydrophilic ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF(4)]) using ammonium hydroxide (NH(4)OH) as a catalyst in the presence of PS seed. Transmission electron microscopy observation of ultrathin cross-sections of the composite particles revealed that the composite particles had a core-shell morphology consisting of a PS core and a Al(OH)(3) shell having high crystallinity. The amount of secondary nucleated Al(OH)(3) could be reduced by dropwise addition of NH(4)OH. Moreover, PS/η-Al(2)O(3) composite particles were successfully prepared by heat treatment of PS/Al(OH)(3) at 300 °C in N(2) atmosphere, which is below the decomposition temperature of PS.     

Rotation mechanism of F1-ATPase: crucial importance of the water entropy effect

We propose a novel picture of the rotation mechanism of F(1)-ATPase, a rotary-motor protein complex. Entropy, which originates from the translational displacement of water molecules, is treated as the key factor in the proposal. We calculate the water entropy gains upon formation of the α-β, α-γ, and β-γ subunit pairs. The gain is given as the difference between the hydration entropy of a subunit pair and the sum of the hydration entropies of the separate subunits forming the pair. The calculation is made using a hybrid of a statistical-mechanical theory for molecular liquids and morphometric approach. The water entropy gain is considered as a measure of tightness of the packing at each subunit interface. The results are highly correlated with the numbers of stable contacts at the subunit interfaces estimated by a molecular dynamics simulation. We also calculate the hydration entropies of three different subcomplexes comprising the γ subunit, one of the β subunits, and two α subunits adjacent to them. The major finding is that the packing in F(1)-ATPase is highly asymmetrical, and this asymmetry is ascribed to the water entropy effect. We discuss how the rotation of the γ subunit is induced by such chemical processes as ATP binding, ATP hydrolysis, and release of the products. In our picture, the asymmetrical packing plays crucially important roles, and the rotation is driven by the water entropy effect.     

Configurational studies of complexes of various tea catechins and caffeine in crystal state

Crystals of the complexes of (+)-catechin (CA) of non-galloylated catechin and (-)-catechin-3-O-gallate (Cg) of galloylated catechin with caffeine were prepared, and their stereochemical structures and intermolecular interactions were determined by X-ray crystallographic analysis. CA formed a 1 : 1 complex with caffeine by intermolecular hydrogen bonds, whereas Cg formed a 1 : 2 complex with caffeine, which was formed by face-to-face and offset π-π interactions and intermolecular hydrogen bonds. A solution of two kinds of non-galloylated catechin, CA and (-)-epicatechin (EC), and caffeine (molar ratio 1 : 1 : 2) in water afforded a 1 : 1 : 2 complex, the crystal structure of which had two layers, one layer in which CA and caffeine formed alternate lines and an other layer in which EC and caffeine formed alternate lines. The 1 : 1 : 2 complex was formed by offset π-π and CH-π interactions and intermolecular hydrogen bonds.     

Real space observation of current-induced magnetic domain wall displacement in Co/Ni nano-wire by photoemission electron microscopy

Current-induced magnetic domain wall (DW) displacement in a Co/Ni nano-wire with perpendicular magnetic anisotropy was investigated in real space by photoemission electron microscopy (PEEM) for the first time. DW velocity determined from the PEEM observation was 40?m?s(-1) for the current density of 2.5?×?10(12)?A?m(-2), which was consistent with the result obtained by the electrical measurement used in our previous reports.     

Observation of X(3872)→J/ψγ and search for X(3872)→ψ'γ in B decays

We report a study of B→(J/ψγ)K and B→(ψ'γ)K decay modes using 772×10? B ?B events collected at the Υ(4S) resonance with the Belle detector at the KEKB energy-asymmetric e(+)e(-) collider. We observe X(3872)→J/ψγ and report the first evidence for χ(c2)→J/ψγ in B→(X_{c ?cγ)K decays, while in a search for X(3872)→ψ'γ no significant signal is found. We measure the branching fractions, B(B(±)→X(3872)K(±))B(X(3872)→J/ψγ)=(1.78(-0.44)(+0.48)±0.12)×10(-6), B(B(±)→χ(c2)K(±))=(1.11(-0.34)(+0.36)±0.09)×10(-5), B(B(±)→X(3872)K(±))B(X(3872)→ψ'γ)<3.45×10? (upper limit at 90% C.L.), and also provide upper limits for other searches.