Unsteady and chaotic characteristics of natural convection field in vertical slots at large Prandtl number

In this study we examined the unsteady and chaotic characteristics of the natural convection field in vertical slots at large Prandtl number. In the computation, temperature dependence of viscosity was partially taken into consideration. As a result we discovered that the spatial region where a significant temperature fluctuation is detected corresponds to the spatial region where the secondary cells exist. The largest Lyapunov exponents calculated from the temperature on the center line have a local maximum at the lower region of the enclosure when the viscosity change was considered. These characteristics agree well with the experimental ones that have been observed by authors (Ishida, Kure and Kimoto 2001).     

Medicinal flowers. II. Inhibitors of nitric oxide production and absolute stereostructures of five new germacrane-type sesquiterpenes, kikkanols D, D monoacetate, E, F, and F monoacetate from the flowers of Chrysanthemum indicum L

The methanolic extract and ethyl acetate-soluble portion from the flowers of Chrysanthemum indicum L., Chrysanthemi Indici Flos, were found to show inhibitory activity against nitric oxide (NO) production in lipopolysaccharide-activated macrophages. Five new germacrane-type sesquiterpenes, kikkanols D, D monoacetate, E, F, and F monoacetate, were isolated from the ethyl acetate-soluble portion. Their absolute stereostructures were elucidated on the basis of chemical and physicochemical evidence, which included application of the modified Mosher's method. The effects of fifteen principal components from the ethyl acetate-soluble portion of this medicinal flower against NO production were examined and, among them, acetylenic compounds and flavonoids were found to show potent inhibitory activity.     

Medicinal flowers. I. Aldose reductase inhibitors and three new eudesmane-type sesquiterpenes, kikkanols A, B, and C, from the flowers of Chrysanthemum indicum L

The methanolic extract from the flowers of Chrysanthemum indicum L., Chrysanthemi Indici Flos, was found to show inhibitory activity against rat lens aldose reductase. By bioassay-guided separation, the active components, such as flavone and flavone glycosides, were isolated from the extract together with three new eudesmane-type sesquiterpenes, kikkanols A, B, and C. The structures of kikkanols A, B, and C were elucidated on the basis of chemical and physicochemical evidence, which included application of the modified Mosher's method.     

Pentamethylcyclopentadienide in organic synthesis: nucleophilic addition of lithium pentamethylcyclopentadienide to aromatic aldehydes and carbon-carbon bond cleavage of the adducts affording the parent aldehydes

Treatment of aromatic aldehyde with lithium pentamethylcyclopentadienide provided the corresponding carbinol in excellent yield. The carbinol returns to the parent aldehyde and pentamethylcyclopentadiene upon exposure to an acid or due to heating. The combination of the two reactions can represent a protection of aromatic aldehyde.     

Medicinal flowers. VI. Absolute stereostructures of two new flavanone glycosides and a phenylbutanoid glycoside from the flowers of Chrysanthemum indicum L.: their inhibitory activities for rat lens aldose reductase

Two new flavanone glycosides, (2S)- and (2R)-eriodictyol 7-O-beta-D-glucopyranosiduronic acids, and a new phenylbutanoid glycoside, (2S, 3S)-1-phenyl-2,3-butanediol 3-O-beta-D-glucopyranoside, were isolated from the flowers of Chrysanthemum indicum L. cultivated in China together with eight flavonoids. The absolute stereostructures of the new compounds were determined on the basis of chemical and physicochemical evidence. Both of the new flavanone glycosides were found to show inhibitory activity for rat lens aldose reductase.     

Bioactive constituents from Chinese natural medicines. XIV. New glycosides of beta-carboline-type alkaloid, neolignan, and phenylpropanoid from Stellaria dichotoma L. var. lanceolata and their antiallergic activities

A new beta-carboline-type alkaloidal glycoside, glucodichotomine B, four new neolignan glycosides, dichotomosides A, B, C, and D, and a new phenylpropanoid glycoside, dichotomoside E, were isolated from a Chinese natural medicine, the roots of Stellaria dichotoma L. var. lanceolata. The structures of the new glycosides were determined on the basis of chemical and physicochemical evidence. Among them, dichotomoside D inhibited the release of beta-hexosaminidase (IC(50)=64 microM) as well as tumor necrosis factor-alpha and interleukin-4 (IC(50)=16, 34 microM) in RBL-2H3 cells. These findings suggest that dichotomoside D is more effective against the late-phase reactions in type I allergy than in the immediate phase.     

Influence of extended π-conjugation units on carrier mobilities in conducting polymers

Carrier mobilities in thin films of copolymers with repeat units consisting of oligothiophenes bridged by Si atoms are measured over a range of doping levels, where the numbers of thienylenes in the repeat unit are 7, 8, 10, 12, and 14. The mobilities for these polymer films increased with the increase in doping level and the mobility enhancement followed an increasing order of the π-conjugation length. The magnitude of the mobility increase for the Si polymer comprising 14 thiophene units reached ca. 10⁴, implying that this π-conjugation length is almost sufficient to reproduce transport properties of polythiophenes.