Measurement of the B(0)-B(0) mixing parameter Deltam(d) using semileptonic B0 decays

We present a measurement of the B0-Bmacr;(0) mixing parameter Deltam(d) using neutral B meson pairs in a 29.1 fb(-1) data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We exclusively reconstruct one neutral B meson in the semileptonic B0-->D(*-)l(+)nu decay mode and identify the flavor of the accompanying B meson from its decay products. From the distribution of the time intervals between the two flavor-tagged B meson decay points, we obtain Deltam(d)=(0.494+/-0.012+/-0.015) ps(-1), where the first error is statistical and the second error is systematic.     

Observation of the color-suppressed decay B( 0)-->D(0)pi(0)

We report the first observation of color-suppressed B( 0)-->D(0)pi(0), D(*0)pi(0), D0eta, and D0omega decays, and evidence for B( 0)-->D(*0)eta and D(*0)omega. The branching fractions are B(B( 0)-->D0pi(0)) = (3.1 +/- 0.4 +/- 0.5)x10(-4), B(B( 0) -->D(*0)pi(0)) = (2.7(+0.8+0.5)(-0.7-0.6))x10(-4), B(B( 0) --> D0eta) = (1.4(+0.5)(-0.4) +/- 0.3)x10(-4), B(B( 0) --> D0omega) = (1.8 +/- 0.5(+0.4)(-0.3))x10(-4), and we set 90% confidence level upper limits of B(B( 0) --> D(*0)eta)<4.6 x 10(-4) and B(B( 0)-->D(*0)omega)<7.9 x 10(-4). The analysis is based on a data sample of 21.3 fb(-1) collected at the Upsilon(4S) resonance by the Belle detector at the KEKB e(+)e(-) collider.     

Observation of B+/- -->omegaK+/- decay

We report the first observation of the charmless two-body mode B+/--->omegaK+/- decay, and a new measurement of the branching fraction for the B+/--->omegapi(+/-) decay. The measured branching fractions are B(B+/--->omegaK+/-)=(9.2(+2.6)(-2.3)+/-1.0)x10(-6) and B(B+/--->omegapi(+/-))=(4.2(+2.0)(-1.8)+/-0.5)x10(-6). We also measure the partial rate asymmetry of B+/--->omegaK+/- decays and obtain A(CP)=-0.21+/-0.28+/-0.03. The results are based on a data sample of 29.4 fb(-1) collected on the Upsilon(4S) resonance by the Belle detector at the KEKB e(+)e(-) collider.     

Diastereoselective synthesis of all stereoisomers of beta-methoxytyrosine,a component of papuamides

beta-Methoxytyrosine (beta-OMeTyr) is a stereoundefined component of papuamides A and B, novel cyclodepsipeptides, with anti-HIV and cytotoxic activities. For structural determination and total synthesis of papuamides, all stereoisomers of beta-OMeTyr were stereoselectively prepared from (S)- and (R)-serine, respectively.     

First isolation of eclipsed vic-disulfoxide: 7,8-dithiabicyclo[4.2.1]nona-2,4-diene 7-exo,8-exo-dioxide

[reaction: see text] The oxidation of 7,8-dithiabicyclo[4.2.1]nona-2,4-diene 7-exo-oxide with dimethyldioxirane (DMD) provided the 7-exo-8-exo-dioxide, the structure of which was determined by X-ray crystallography [S-S 2.341(2) A and 90 degree angle O-S-S-O 4.1(3) degrees ]. The exo attack of DMD to give the exo,exo-dioxide was kinetically more favorable than the endo attack to give the endo,exo-dioxide. DFT calculations showed that the exo,exo-dioxide is thermodynamically more stable than the other stereoisomers.     

Erythrocyte-like liposomes prepared by means of amphiphilic cyclodextrin sulfates

A novel class of sulfated glycolipids with excellent self-assembling capacity to form stable monolayers at an air-water interface and specific erythrocyte-like liposomes was synthesised from alpha, beta, and gamma-cyclodextrins as starting materials.     

Heat Resistance and Local Structure of FeCl2-Absorbed Crosslinked Poly(γ-Glutamic Acid)

Fiber of Japanese food natto (Bacillus subtilis) is known to be superabsorbent poly(-glutamic acid) (PGA). NaCl particles precipitate in FeCl₂-absorbed crosslinked PGA when heated at crystallization temperature of 320 °C for 10 to 60 min. After heat treatment the Mössbauer spectrum of FeCl₂-crosslinked PGA consists of a quadrupole doublet due to FeCl₂·2H₂O. The Mössbauer spectrum of anhydrous FeCl₂ reagent heated under the same condition shows an intense sextet due to -Fe₂O₃ . These results prove that the superabsorbent polymer, crosslinked PGA, has higher heat resistance.