The CH/π interaction is a kind of weak hydrogen bond (<1 kcal·mol^-1) occurring between soft acids (CHs) and soft bases (π-electron systems). Evi-dence for such a weak attractive molecular force has been obtained by various methods, including X-ray crystallography, IR, NMR, CD spectroscopies, and combination of these methods. The conclusion has been supported by molecular orbital calculations. The characteristic features of this attractive force is that CHs and π-groups are arranged generally in chemical structures in a symmetrical manner and have many chance to interact. Moreover, the interaction may occur in protic media. The problems of conformation, chromatography, and the structure of proteins have been discussed in the light of the CH/7 interaction. Suggestions have been made, on ground of these findings, as for the applications of the concept in life science and materials science.

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The authors established a method for estimating the mixing ratios of oil mixtures on the basis of their fatty acid composition data by quadratic programming. This method was applied to the mixtures of sesame oil, soybean oil, rapeseed oil and rice bran oil. The results were highly accurate provided exact data were available for the pure oils used in mixing. The error between estimated and actual mixing ratio derived primarily from variation in fatty acid composition of pure oils among different sources. The distribution ranges of the estimated mixing ratio for binary mixtures of sesame and adulterant oil were calculated and the results confirmed the effectiveness of this method.

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The effects of pressure on the solution properites of tetradecane-1-sulfonates with divalent cation of separate electric charges as counterion [1, 1'- (1, ω-alkanediyl) bispyridinium tetradecane-1-sulfonate]
_??_ON+_- (CH₂) n-⁺NO_??_ (C₁₄H₂₉SO₃^-) ₂ : n=2, 4, 6, 8, 10
were examined at 40°C by the critical micelle concentration (cmc) and by the aqueous solubility. Specific conductivity of the surfactants below the cmc was found to increase monotonously with pressure. Longchain surfactant anions would thus appear to associate with the divalent cations below the cmc, the extent of which decreasing with increasing pressure. The cmc of all surfactants was found to have a maximum around 140 MP as conventional ionic surfactants. The volume change on micellization, Δ Vm, was determined based on the pressure dependence of cmc, and Δ Vm was observed to decrease more rapidly with pressure for shorter charge separation of the counterions. Dynamic light scattering was measured for micellar solutions, and the results indicated the hydrodynamic radius of micelles to be considerably controlled by divalent cationic counterions of increasing charge separation.

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The solubilization of two binary perfume systems (eugenol-linalool and eugenol-d-limonene) by sodium dodecyl sulfate was determined in terms of solubilizing capacity (SC) of the surfactant. The experimental SC of each perfume in an eugenol-linalool system was almost equal to the ideal SC. In eugenol-d-limonene system, however, the SC of eugenol and d-limonene differed positively from the ideal SC of the perfumes. This result would be attributed to the change in micellar structure (micellar diameter) caused by the solubilization of these perfumes and to the location of the perfumes in the micelle.

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The structures and antioxidative activity of retro carotenoids from the berries of the Japanese yew, Taxus cuspidata were studied. Three retro carotenoids, rhodoxanthin (1), eschscholtzxanthone (2) and eschscholtzxanthin (3) were identified by spectroscopy. The stereo-structure of (2) was fully determined based on ¹H-NMR and CD spectral data. These retro carotenoids showed stronger antioxidative activity for lipid peroxidation induced by free radical and singlet oxygen than that of β-carotene.

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Using a heat conduction calorimeter with very high resolution of 5×10^-5 J/deg cm³, we measured specific heat capacity, C_pL, between 25°C and 35°C of dimyristoylphosphatidylcholine (DMPC) in aqueous dispersions. Anomaly in C_pL_, between 28.60°C and 29.50°C was noted; i.e., the curve for C_pL against T first decreased and then exhibited an inflection point at 28.96°C before flattening. The inflection point at 28.96°C corresponded to the high order phase transition in DMPC bilayers that could occur through an intermediary phase.
The dynamic properties of C_pL indicated T^* to be critical for the occurrence of high order transition of the bilayers. The time to reach equilibrium on changing temperature increased dramatically between 28.60°C and 28.96°C, increasing as (T-T) ^-1, but at T>T^*, no dramatic “slowing-down” phenomenon was observed. This “slowing-down” near T^* is a general characteristic of critical phenomena in high order transition. Thermodynamic parameters for high order bilayer transition were obtained fromC_pLT data over this temperature interval. The value of 3.43 J/mol or 8.73 ×10^-3 erg/cm² of bilayer was found to be enthalpy change, in agreement with other data for interaction energy between neutral bilayers. A possible relationship of membrane bilayer stability with these newly identified dynamic properties of transition is discussed.

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The elution properties of various polar and apolar nonionic compounds on supercritical fluid chromatography (SFC), using a silica gel column were studied. Relationships among capacity factor (k'), adsorption energy (S⁰), adsorption cross area (A_s) and solvent strength (ε⁰), were reported in thin layer chromatography as theoretically [log k' =α (S⁰-A_s×ε⁰) +C] (C, column constant and α, activation factor of the silica gel column). The elution time of each compound could be predicted and chromatographic conditions could be easily established by the proper choice and concentration of modifier. These findings were applied, in a step gradient mode, to the fractionation of toiletry and cosmetic ingredient mixtures. Hydrocarbons, fatty alcohols, alkylglycerylethers, fatty acid mono- and di-ethanolamides were found to be fractionated quite efficiently.

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Examination was made of the behavior of polyethyleneglycol lauryl ether (non-ionic surfactant) in aqueous ethanol solution. Surface tension, penetration power, foaming power, foam stability, viscosity, dynamic surface tension and solubility of lauryl ether with different numbers of P.O.E. concentrations of aqueous ethanol were measured.
From results, the following became apparent. At the air/water interface, lauryl ether forms an absorption film. When ethanol is added to water at 10%, laurly ether begins to dissapear from the surface, and at 20%, surfactant molecules are not present on the surface. At the bulk of the solution, solubility decreased to 1/41/5 that of water, indicating that micells to have changed.

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Absolute configurations of mytiloxanthin and 9-E-mytiloxanthin isolated from the mussel Mytilus coruscus were confirmed to be 3R, 3'S, 5'R by using modified Mosher's method.

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The antioxidative activity of eleven phenolic compounds, two of which, (8) and (11) were new compounds, were isolated from the fruit of Boreava orientalis (Cruciferae), was examined by methyl linolate peroxidation which was induced by 2, 2' -azobis (2, 4-dimethyl-vareronitrile) (AMVN). All phenolic compounds showed antioxidative activity. The activity of sinapic acid (10) and its derivatives, (9) and (11), was remarkably high.

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