Conformational change of poly(methylphenylsilane) induced by the photoisomerization of pendant azobenzene moiety in the film state

Conformational change of the main chain of poly(methylphenylsilane) functionalized with pendant azobenzene has been studied in the solution and in the film state. The conformation of the main chain was found to depend on the molar ratio of the Si units with and without the pendant azobenzene moiety. The inflection region for the conformational change was 0.3–0.5 of the molar ratio. The conformation of the main chain changed by the photoisomerization of the pendant azobenzene moiety in the film state. The efficiency of the conformational change of the main chain increased with the decrease of the molar ratio, accompanied by the highest final value of degree of the conformational change at the molar ratio of 0.5. The reverse conformational change was induced by heating.     

Design and synthesis of fluorescence-labeled closo-dodecaborate lipid: its liposome formation and in vivo imaging targeting of tumors for boron neutron capture therapy

The fluorescence-labeled closo-dodecaborane lipid (FL-SBL) was synthesized from (S)-(+)-1,2-isopropylideneglycerol as a chiral starting material. FL-SBL was readily accumulated into the PEGylated DSPC liposomes prepared from DSPC, CH, and DSPE-PEG-OMe by the post insertion protocol. The boron concentrations and the fluorescent intensities of the FL-SBL-labeled DSPC liposomes increased with the increase of the additive FL-SBL, and the maximum emission wavelength of the liposomes appeared at 531 nm. A preliminary in vivo imaging study of tumor-bearing mice revealed that the FL-SBL-labeled DSPC liposomes were delivered to the tumor tissue but not distributed to hypoxic regions.     

Liposome solubilization induced by surfactant molecules in a microchip

The dynamics of liposome solubilization was monitored by dynamic light scattering and optical microscopy. A newly designed Y-shape microchannel connected to a room was incorporated into a microchip and the reaction processes of the liposome suspension and surfactant solution were observed in the room after mixing the two fluids and stopping the flow. By using this microchip, we succeeded in real-time monitoring of liposome solubilization and the following dynamic processes of solubilization were proposed: 1) Deformed liposomes become spherical. 2) The liposome size increases until the surfactant/liposome ratio in the liposome membrane reaches a threshold value. 3) Mixed micelles of surfactants and phospholipids are released and the liposomes collapse.     

Total synthesis and structural revision of hericerin

The total synthesis of hericerin, a pollen growth inhibitor from Hericium erinaceum, was achieved. We found that the reported structure of hericerin should be revised to be the carbonyl regioisomer.     

Cyclizations producing hydrindanones with two methyl groups at the juncture positions mediated by samarium diiodide and electrolysis

One-electron reductive intramolecular cyclization of enones with ketones or aldehydes mediated by samarium diiodide and electrolysis to afford cis-trimethyl- hydrindanolones. The reactions gave selectivities ranging from 1:1 to 100:0 depending on the conditions.     

New triterpenoid saponins from fruit specimens of Panax japonicus collected in Toyama prefecture and Hokkaido (2)

Four new dammarane-type triterpenoid saponins, chikusetsusaponin FT(1) (1), chikusetsusaponin FT(2) (2), chikusetsusaponin FT(3) (3), chikusetsusaponin FT(4) (4), and six known triterpenoid saponins, chikusetsusaponin FK(4) (8), chikusetsusaponin FK(5) (9), chikusetsusaponin FK(2) (10), chikusetsusaponin FK(3) (11), chikusetsusaponin LN(4) (12), and chikusetsusaponin IVa (14), were isolated from the fruits of Panax japonicus C. A. MEYER, collected in Toyama prefecture, Japan, and five new dammarane-type triterpenoid saponins, chikusetsusaponin FT(1) (1), chikusetsusaponin FT(3) (3), chikusetsusaponin FT(4) (4), chikusetsusaponin FH(1) (5), chikusetsusaponin FH(2) (6), and eight known triterpenoid saponins, ginsenoside Re (7), chikusetsusaponin FK(5) (9), chikusetsusaponin FK(2) (10), chikusetsusaponin FK(3) (11), chikusetsusaponin LN(4) (12), 28-desglucosylchikusetsusaponin IVa (13), chikusetsusaponin IVa (14), and chikusetsusaponin V (15), were isolated from the fruits of P. japonicus C. A. MEYER, collected in Hokkaido, Japan. The structures of new chikusetsusaponins were elucidated on the basis of chemical and physicochemical evidences.     

Observation of stable superdense core plasmas in the large helical device

In reduced recycling discharges in the Large Helical Device, a super dense core plasma develops when a series of pellets are injected. A core region with density as high as 4.5 x 10(20) m(-3) and temperature of 0.85 keV is maintained by an internal diffusion barrier with very high-density gradient. These results may extrapolate to a scenario for fusion ignition at very high density and relatively low temperature in helical devices.     

Bioluminescence color modulation of Vibrio fischeri strain Y1 coupled with alterable levels of endogenous yellow fluorescent protein and its fluorescence imaging

Bioluminescence (BL) (lambda(max) approximately 535 nm) of Vibrio fischeri strain Y1 has been previously characterized in terms of the fluctuation in intracellular levels of yellow fluorescent protein (YFP). In this study fluorescence microscopic analysis has revealed that yellow fluorescence, as well as blue fluorescence attributable to a luciferase intermediate, is localized to the periphery of V. fischeri Y1 cells. This finding indicates that both YFP and the luciferase are present in the vicinity of the cell membrane. By using cyanide to enhance yellow BL, it has been shown that BL modulation is coupled with the fluctuations in the intracellular levels of YFP and the primary emitter. On the basis of the BL characterization, combined with results of a sedimentation experiment, it has been shown that larger cells produce a relatively stronger yellow BL. Two-dimensional gel electrophoresis of cell-protein extracts has shown that the YFP level is more alterable than the luciferase level. It is postulated that the yellow BL modulation takes place in connection with cell growth.     

Formation of metal-lustrous organic crystals from 2-aryl-1-(4-methoxyphenyl)-5-(5-tricyanoethenyl-2-thienyl)pyrroles

Various 2-aryl-1-(4-methoxyphenyl)-5-(5-tricyanoethenyl-2-thienyl)pyrroles (3) were synthesized. When the 2-aryl group of 3 is phenyl, 4-tolyl, and 4-methoxyphenyl, organic crystals with greenish yellow metallic luster are formed. In contrast, a 2-(4-fluorophenyl) derivative of 3 gives gold-like lustrous crystals. The relation of their crystal structures with the appearance of metallic color is mentioned.     

Greenish metal-lustrous organic crystals formed from 1-aryl-2-(2-thienyl)-5-(5-tricyanoethenyl-2-furyl)pyrroles

On the treatment of 1-aryl-2-(2-furyl)-5-(2-thienyl)pyrroles with tetracyanoethylene, 1-aryl-2-(2-thienyl)-5-(5-tricyanoethenyl-2-furyl)pyrroles were produced. These compounds formed crystals with greenish metallic luster. In their solid-state UV-vis-NIR diffuse reflection-absorption spectra, absorption band corresponding to metallic reflection spreads in the range of 550-900 nm. Furthermore, strong absorption appeared below 520-540 nm. This absorption results in the appearance of green color. Single-crystal X-ray crystallographic analysis revealed the crystal structure of 1-(4-methoxyphenyl)-2-(2-thienyl)-5-(5-tricyanoethenyl-2-furyl)pyrrole (2c). The distinct features of the crystal structure are as follows: (1) the thiophene-pyrrole-furan-tricyanoethenyl π-system is approximately flat; (2) the conformational relation between the pyrrole ring and the furan ring is anti, that is, these rings are pointing in opposite directions and the dihedral angle of N-C-C-O=180°; (3) as a result, the tricyanoethenyl group is far from the 4-methoxyphenyl group; (4) the molecules of 2c are arranged in a ribbon structure; (5) the ribbons are assembled side-by-side to form a terraced layer; (6) the layers stack so that the π-orbitals of 2c become close to each other.