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Surface enhanced Raman scattering (SERS) spectra of organic monolayers were measured on various types of polycrystalline and single crystalline Pt substrates with nanometric or atomic surface features, including heteroepitaxial Pt monolayers, using sphere-plane type nanogap structures. Although atomic geometry and electronic structures of a metal surface significantly influence metal-molecule interactions, such effects are often hindered in conventional SERS measured on a roughened surface because of the spectral information averaging at various adsorption sites. In this study, the use of atomically defined Pt surfaces revealed detailed surface effects; the observed preferential adsorption geometry on each surface was well explained by atomic surface arrangements. The peak shift of the intramolecular vibration in the anchor group was in good agreement with the variation of the d-band center of Pt substrates. Moreover, in electrochemical SERS study the Stark shift of an extramolecular vibrational mode at around 400 cm(-1), which is not accessible in infrared absorption spectroscopy, was monitored on an atomically defined heteroepitaxial Pt monolayer electrode.

The effects of asymmetrical tension on the vibratory pattern of the vocal cords were studied in two kinds of experiments: 1) high speed motion picture photography of artificial voice production in excised canine and human larynges, and 2) computer synthesis of voice and vocal cord vibration via a theoretical model incorporating the physiological parameters required for phonation. In both approaches the asymmetrically tensed vocal cords consistently vibrated in three distinct modes which depend partly on the rest positions of the vocal cords; Type I. For rest positions at or near closure, the two cords vibrate at the same frequency with glottal closure every period, and with tense cord preceding the lax one in phase and with the line of contact moving toward the tenser cord during the closed phase. The voice produced is not hoarse; Type II. For wider rest positions glottal closure occurs irregularly, the vibrations become complex and less periodic, and the voice becomes hoarse; Type III. The glottis never closes and the vibrations become more periodic with reduced amplitude. Supplementary stroboscopic observations suggest a precedure for diagnosing tension asymmetry and the implications for surgical treatment for disorders of vocal pitch are discussed.

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Three neolignans, known as magnolol [1], honokiol [2] and the new monoterpenylmagnolol [3], were isolated from the bark of Magnolia officinalis as inhibitors of Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). The structure of 3 was determined from 2D nmr spectral data and difference nOe experiments. The MeOH extract of this plant and magnolol exhibited remarkable inhibitory effects on mouse skin tumor promotion in an in vivo two stage carcinogenesis test. This investigation indicates that these neolignans and the extract might be valuable antitumor promoters.

Gambir, an official pharmacopoeic medicine in Japan, is the aqueous extract of the leaves and young twigs of Uncaria gambir ROXB. (Rubiaceae).2) The extract has been used for the treatment of diarrhea and sore throat as an astringent medicine in Southeast Asia, 3) and also for hoarseness, as an ingredient of the kampo medicine "Kyoseihatekigan."Flavan monomers, (ϩ)-catechin (1) and (ϩ)-epicatechin (2), 4) several other dimeric compounds 5) related to 1, as well as alkaloids, 6,7) have been reported to be the constituents. Our investigation on the polyphenolic contents of a manufactured gambir product led to the isolation of 1, 2, and seven dimeric flavans 3-9. Although the seven dimeric flavans were known compounds, the present study revealed that the stereostructures of four of the chalcane-flavan dimers should be revised to 6-9. Their 1 H-and 13 C-NMR spectral assignments are also shown here, since those were not reported in detail previously. 5,8) Results and DiscussionA manufactured product of gambir purchased in Japan was extracted with MeOH, and the extract was fractionated by column chromatography on Dia-ion HP-20 using aqueous MeOH. (ϩ)-Catechin (1) was crystallized from the eluate with 20% MeOH, and the mother liquor was subjected to column chromatography on a Toyopearl HW-40 to give a fraction containing both monomeric and dimeric flavans. The fraction was further chromatographed on octadecylsilyl (ODS) silica gel, Sephadex LH-20, and MCI-gel CHP-20P columns to give (ϩ)-catechin (1), (ϩ)-epicatechin (2), procyanidin B1 (3), 9,10) procyanidin B3 (4), 11) gambiriin C (5), 5) and gambiriin A1 (6). The eluate, with 40% MeOH from the column of Dia-ion HP-20, was separated in an analogous way to give gambiriin A2 (7), gambiriin B1 (8), and gambiriin B2 (9). Gambiriin A1 (6) was obtained as an amorphous powder. The dimeric molecular formula, C 30 H 28 O 12 , was indicated by the [MϩH] ϩ ion peak at m/z 581 in the electrospray-ionization (ESI)-MS. The showed a large coupling constant (7.5 Hz), indicating that the lower unit was 2,3-trans catechin. The 2,3-trans structure was also validated by the 13 C-NMR spectrum, which showed the C-2 L signal at d 82.5. The remaining set of the methine-methine-methylene protons [d: 2.56 (H-ga U ), 2.95 (Hgb U ), 4.68 (H-b U ), 4.75 (H-a U )] was attributable to the substituted propyl group in the chalcane structure. The molecular formula of 6, which was indicated by the ESI-MS, also substantiates this open-chain chalcane structure.The rotating frame nuclear Overhauser effect spectroscopy (ROESY) of 6 showed correlations of H-a U /H-2Ј L and Hb U /H-2Ј L , indicating the presence of an interflavonoid link between position C-8 L and the upper chalcane unit (C-a U ) (Fig. 2). These correlations would not be observed if the linkage occurred at C-6 L . The aliphatic protons of 6 appeared as broad signals, due to the restricted rotation around the interflavonoid linkage, which confirmed the location of the linkage at C-8 L .The assigned structure of 6 based on these data suggest...

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A facile synthesis method or ruthenium(II) polypyridine complexes by microwave irradiation has been developed. This method greatly reduces reaction time from 4 hours to 20 minutes with better yield(60–90%). The procedures are simple and may be used for synthesis of a variety of metal polypyridine complexes.