Nutritional improvement of soybean oil via lipase-catalyzed interesterification

In order to decrease the content of linoleoyl moiety in soybean oil, soybean oil that contains 22.8% oleoyl, 54.8% linoleoyl, and 7.1% α-linolenoyl moieties as molar acyl moiety composition was interesterified in hexane with oleic acid or α-linolenic acid, using an immobilized sn-l,3-specific lipase (Lipozyme® IM) fromMucor miehei. The reactions were carried out in a batch reactor at 37°C in the following system: molar ratio of fatty acid to soybean oil = 1.0 ～ 6.0, 5.0 mL of hexane/500 μmol soybean oil, and 10.0 or 15.0 batch interesterification units of enzyme/500 μmol soybean oil. Under these reaction conditions, the rates of interesterification of acyl moieties in soybean oil were of the order: stearoyl > palmitoyl > linoleoyl > oleoyl > α-linolenoyl, and the reaction with oleic acid occurred without a significant loss of α-linolenoyl moiety. At the molar ratio of 3.0 and the reaction time of 6 h, triacylglycerols (TGs), which contain 50.8% oleoyl, 38.8% linoleoyl, and 5.4% α-linolenoyl moieties, were produced in the reaction with oleic acid; TGs that contain 13.5% oleoyl, 40.8% linoleoyl, and 40.4% α-linolenoyl moieties were obtained with α-linolenic acid. Approximately 86-88% of the interesterification of linoleoyl moiety, which occurred in 10 h, took place within 1 h.     

Application of optically transparent electrodes: Part III. A double-illumination-step chronoamperometric study of the kinetics of the dark back reaction of photochemically generated leucothionine with iron(III) in the iron-thionine system

Experimental transient photocurrent-time curves caused by a step-functional illumination through an optically transparent electrode (OTE) are compared with theoretical ones for the iron-thionine system. where not only can photochemically generated leucothionine be oxidized and consequently be monitored electrochemically at the OTE, but it can also be oxidized homogeneously with ferric ion in solution. It is also described how the rate constants of this dark back reaction in solution can be determined by double-illumination-step chronoamperometry. The second order rate constant for the reaction was determined to be 190±30 M^?1 s^?1 at 15±1°C     

High-resolution infrared spectrum of chlorine dioxide: The ν1 fundamental band

The B-type ν₁ fundamental band of chlorine dioxide has been observed with the resolution of 0.06 cm^?1, and several molecular parameters have been derived for the ³⁵ClO₂ isotopic species. The spectrum has been partially resolved by a tunable diode laser, and many doublet structures have been observed providing sufficient data to determine the spin-rotation interaction constants.     

Analysis of a class of undesired multimode oscillations

The behavior of a negative-resistance circuit in which the parameters permit self-sustained oscillations to occur is discussed. In such a circuit, undesired oscillations of higher frequency caused by parasitic elements can exist in addition to normal oscillations. Parasitic oscillations are described by second-order simultaneous non-linear differential equations, taking into account of existence of the shunt capacitance, lead inductance and resistance of a negative-resistance element. Assuming that the frequency of the parasitic oscillations is sufficiently high compared with that of the desired normal oscillations, the approximate periodic solutions are obtained by using a method of averaging. In addition, the theoretical results are compared with the observed behavior of an experimental oscillator having similar parameters.     

The nature of the vibronic coupling in a metalloporphyrin and its Raman scattering

It has been shown that a Raman line of a nontotally symmetric vibration (b_1g, b_2g, or a_2g) of a metalloporphyrin (D_4h) can be caused, not only by a vibronic coupling between the first ($\text{A}\text{?}$) and second ($\text{B}\text{?}$) excited electronic states but also by a vibronic coupling within one of the electronic states (let us call the former the QS mechanism and the latter the QQ and/or SS mechanism). A simple formulation has been made for each of those different mechanisms, so that a numerical calculation can be made of the excitation profile of a Raman scattering for a given set of coupling constants and damping factors. Next, the result of an examination is given of the excitation profile of the Raman scatterings of some of the b_1g, b_2g, and a_2g vibrations of nickel octaethylporphyrin and nickel octaethyltetrachloroporphryin. Most of the Raman lines of these nontotally symmetric vibrations show a resonance effect only in the Q-band ($\text{A}\text{?}\text{←}\text{X}\text{?}$) region but not in the Soret-band ($\text{B}\text{?}\text{←}\text{X}\text{?}$) region. On the basis of this fact, it has been suggested that those Raman lines are caused mainly by the QQ mechanism rather than the QS mechanism. The observed vibrational structure of an excitation profile also seems to support this suggestion.     

Infrared spectra of polymer solutions. I. Conformational stability of isotactic polymer chains in solution

The infrared spectra of isotactic polystyrene, polypropylene, and poly-p-chlorostyrene were measured in dilute solutions or gels at various temperatures ranging from room temperature to ?100°C. For isotactic polystyrene and polypropylene, all the absorption bands characteristic of the helical conformation of the molecules increase in intensity with decreasing temperature, and show intensities at low temperature as strong as in the highly crystallized samples. This suggests that the molecules can assume very regular conformations even in solution. Similar temperature dependence of the spectra was observed for a homogeneous gel of isotactic poly-p-chlorostyrene, which is believed to be noncrystalline. These experimental facts lead to the conclusion that the stability of the TG type helical conformation of these isotactic polymers may be ascribed to the intramolecular forces within a molecule. The fact that these spectral changes are reversible has permitted a thermodynamic treatment of the conformational regularity in solution on the basis of the infrared data. The temperature dependence of the absorption intensities has been interpreted quantitatively by a simple statistical mechanical model, and the enthaply and the entropy differences between the helical and the random states of the monomeric residue in the molecular chain have been estimated.     

Disjointness of the KMS-states of different temperatures

Disjointness of (KMS)-states of different temperatures is proved.     

Structural studies of pressure-crystallized polymers. I. Heat treatment of oriented polymers under high pressure

A convenient pressure apparatus was designed for crystallization of high polymers under hydrostatic pressure up to 5000 atm. Melt crystallization as well as heat treatment under various temperatures and pressures was carried out on several polymers, and the effects of pressure on the molecular and crystal structures of the samples are discussed. Heat treatment of syndiotactic polypropylene under high pressure yields a new crystal modification rather than the previously known helix and planar zigzag modifications. Of the three modifications of poly(vinylidene fluoride), modification III was found as a high-pressure phase for specimens in the unoriented state, while modification I was obtained as the most stable one on heat treatment of oriented specimens under high pressure. Heat treatment under high pressure converts ordinary isotactic poly-4-methylpentene-1 with a lower density than the noncrystalline value, to a new crystal modification with higher density. As is reasonable, the dense modification is stable in a high-pressure range. For these three cases, the orientation of specimens was found to remain unchanged during the transitions, which must therefore occur in the solid state.     

Conformational and packing stability of crystalline polymers. VI. Stable chain packing of polyethylene

The stable packings of polyethylene chains were investigated by intermolecular potential energy calculations based on various chain-assembly models. The structures of the two crystal modifications of polyethylene (i.e., orthorhombic and the monoclinic), together with their cell constants and the setting angles, were well reproduced. The packing modes of polymethylene chains found in various alkane derivatives were also explained by the energy minima of the chain-assembly models. In these calculations, several sets of potential functions were tried and three sets of functions were found to reproduce conformations of single polymer chains, the cell constants of polyethylene at low temperature, and those at room temperature.     

A simulation of key aspects of a primary process in natural photosynthesis by a Langmuir-Blodgett film assembly

An advanced Langmuir-Blodgett (LB) assembly designed to replicate the three key aspects (antenna, reaction center, and quinone pool) of a primary process in natural photosynthesis was successfully fabricated by alternate deposition of a mixed monolayer of an artificial reaction center and an antenna pigment and a pure bilayer of a second donor.