Gas permeability and side chain structure of poly(γ-benzyl L-glutamate)

Three structural modifications of poly(γ-benzyl L -glutamate) (PBLG), forms A, B, and C, were prepared by varying the casting solvents and casting temperature. From x-ray analysis, infrared absorption spectroscopy, differential scanning calorimetry, and viscoelastic measurements, it is concluded that form A of PBLG is characterized by intramolecular stacking between the benzene rings in the side chain, form B exhibits intermolecular stacking, and form C has no stacking. The transition which corresponds to the breakdown of stacking of form A at 135°C is irreversible, while that of form B at 110°C is reversible. The degree of stacking is larger for form A than for form B. These structural features of the side chain region reflect the permeation and sorption behavior of carbon dioxide. Breakdown of stacking between benzene rings causes an abrupt increase in permeability in both form A and form B, and the permeation behavior for form A is not reversible, as is suggested from the irreversibility of the transition. The larger the degree of stacking, the lower is the amount of sorption. Although stacking is considered to affect the sorption site (solubility) and molecular motion, its influence on solubility is more evident in the temperature range up to about 50°C.     

Formation of trimers of α-tocopherol and its model compound, 2,2,5,7,8-pentamethylchroman-6-ol,in autoxidizing methyl linoleate

The reaction products of α-tocopherol and its model compound, 2,2,5,7,8-pentamethylchroman-6-ol, during the autoxidation of methyl linoleate at 37 C were investigated. Two isomeric trimers were obtained as the major reaction products of α-tocopherol, and a trimer was obtained as that of its model chroman. The structure of each trimer has been characterized by IR, UV,¹H and¹³C NMR, and mass spectroscopy. The¹³C NMR spectra showed the presence of a quaternary carbon atom and a carbon atom bearing two oxy substituents in the molecule. On methanolysis of each trimer, equimolar amounts of the 5-methoxymethyl compound and the dihydroxy dimer were formed, indicating the presence of a ketal group in the molecule. From these results, new trimeric structures are proposed. The reaction products of α-tocopherol could be well-separated by reverse-phase high performance liquid chromatography. When methyl linoleate was autoxidized in the presence of 1 mol% α-tocopherol, spirodiene dimer was the initial reaction product of α-tocopherol, and trimers were formed with the decrease of α-tocopherol.     

Structural control of core/shell polystyrene microcapsule‐immobilized microbial cells and their application to polymeric microbioreactors

Polystyrene microcapsules possessing a large single core and highly microporous wall were prepared as immobilization supports for microbial cells by a new method based on phase separation of polystyrene within a mixed organic solvent system in an oil‐in‐water (o/w) emulsion. The structures of core and micropore were controlled by changing the concentration of isooctane in the organic phase and the temperature of solvent evaporation. The immobilization of baker's yeast into the polystyrene microcapsules was carried out by entrapping the yeast into calcium alginate beads before encapsulating in the microcapsules and followed by removing the beads with HCl solution. The morphology of the microcapsules was observed by means of SEM, and the activity of the immobilized yeast was evaluated by using the microcapsules in ethanol fermentation. It was found that the formation of the core and wall pore was remarkably influenced by the isooctane concentration, and the diameter of the core was affected by the temperature of solvent evaporation. The yeast was successfully immobilized into the polystyrene microcapsules at a high density and a high catalyst activity by the proposed immobilization method. Furthermore, the polystyrene microcapsules exhibited a high operational stability in the repeated batchwise fermentation test. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1966–1975, 2003     

Reaction of α-tocopherol with alkyl and alkylperoxyl radicals of methyl linoleate

α-Tocopherol was reacted with alkyl and alkylperoxyl radicals at 37°C in bulk phase. The lipid-free radicals were generated by the reaction of methyl linoleate with the free radical initiator, 2,2′-azobis(2,4-dimethylvaleronitrile) (AMVN) under air-insufficient conditions. The products were isolated by high-performance liquid chromatography. Their structures were identified as 2-(α-tocopheroxy)-2,4-dimethylvaleronitrile (1), a mixture of methyl 9-(8a-peroxy-α-tocopherone)-10(E),12(Z)-octadecadienoate and methyl 13-(8a-peroxy-α-tocopherone)-9(Z),11(E)-octadecadienoate (2), methyl 9-(α-tocopheroxy)-10(E),12(Z)-octadecadienoate (3a), methyl 13-(α-tocopheroxy)-9(Z),11(E)-octadecadienoate (3b), α-tocopherol spirodiene dimer (4) and α-tocopherol trimer (5). When methyl linoleate containing α-tocopherol was oxidized with AMVN under airsufficient conditions, the main products were 8a-alkyl-peroxy-α-tocopherones (2). In addition to these compounds, 6-O-alkyl-α-tocopherols (1, 3a and 3b) were formed when the reaction was carried out under air-insufficient conditions. The results indicate that α-tocopherol can react with both alkyl and alkylperoxyl radicals during the autoxidation of polyunsaturated lipids.     

Study on so called "cellular effect" of methotrexate on choriocarcinoma and its mode of manifestation (author's transl)

The "cellular effect" i.e. temporary elevation of HCG titer may not be infrequently experienced during course of chemotherapy against choriocarcinoma. Present paper is to clarify real view of the effect and mechanism of its manifestation by using a cell-line (GCH-nu). 1) Cellular growth was suppressed moderately by 10(-7), 10(-6) and 10(-5)M MTX. 2) During 2-4 days of administration at these concentrations of MTX HCG per ml medium was elevated 5 times. HCG in cells per mg protein were also higher 5-7 times. 3) HCG-beta in media was enhanced 5-7 times in MTX group. 4) Estrone, estradiol and progesterone were not altered. 5) Choriocarcinoma cells developed marked enlargement of nuclei and cells, multinucleation and cytoplasmic vacuolization. 6) Cytochemistry of heat stable ALP revealed increased activity especially in cells with morphological changes. ALP examined by biochemical method was enhanced 5 times. 7) Amount of protein per cell increased 10 times after giving MTX. Real view of so-called "cellular effect" includes elevations of HCG-beta and ALP activity as well as HCG, whereas sex steroids are not apparently related. The data in addition to morphological and cytochemical changes reveal that MTX may induce differentiation of choriocarcinoma cells into those of syncytial type, which then sustain the "cellular effect".     

A novel pixel memory using integrated voltage‐loss‐compensation (VLC) circuit for ultra‐low‐power TFT‐LCDs

Abstract— A novel pixel memory using an integrated voltage‐loss‐compensation (VLC) circuit has been proposed for ultra‐low‐power TFT‐LCDs, which can increase the number of gray‐scale levels for a single subpixel using an analog voltage gray‐scale technique. The new pixel with a VLC circuit is integrated under a small reflective electrode in a high‐transmissive aperture‐ratio (39%) 3.17‐in. HVGA transflective panel by using a standard low‐temperature‐polysilicon process based on 1.5‐μm rules. No additional process steps are required. The VLC circuit in each pixel enables simultaneous refresh with a very small change in voltage, resulting in a two‐orders‐of‐magnitude reduction in circuit power for a 64‐color image display. The advanced transflective TFT‐LCD using the newly proposed pixel can display high‐quality multi‐color images anytime and anywhere, due to its low power consumption and good outdoor readability.     

Development of a real-time beam current monitoring system for microbeam scanning-PIXE analysis using a ceramic channel electron multiplier

Microbeam scanning-PIXE (micro-PIXE) analysis is a useful method for obtaining information of multi-elemental distribution in samples by two-dimensional images of sample surfaces such as mammalian cells, tissues, and other environmental monitoring species. In addition to elemental distribution information, quantitative analysis is in demand for further investigations of environmental and biomedical studies concerning heavy metals accumulated in terms of cells and sub-cellular organelles. To make quantitative analysis possible, a real-time beam monitoring system that gives a precise number of ions, and an output independent from a sample that enables one to keep a beam resolution of micrometer size is required. In this paper, we report on the development of beam current monitoring. The beam current was monitored using a ceramic channel electron multiplier (CEM) to detect secondary electrons induced from a 50 nm thick carbon film (10 μg/cm²). This carbon film was attached to a sample holder, which was set at the targeted sample position. The output value of the CEM was proportional to the Faraday cup installed just after the sample position. The beam resolution was measured using off-axis STIM by scanning a copper grid, and was estimated at 1.79 and 1.72 μm for the horizontal and vertical directions, respectively, sufficient for routine micro-PIXE analysis.     

Electrooptical‐responsive microsphere with ferroelectric liquid crystalline segments

We synthesized a ferroelectric liquid crystalline monomer (4‐[4′‐(7‐octeneloxy)benzoyloxy]benzoate‐2‐methylbutyester, OBBM) possessing both carboxyl p‐benzolxybenzoate and carboxyl (s)‐(‐)‐2‐methylbutylester as a mesogenic group in its side chain. The liquid crystalline and styrene monomers were employed to make matrices of microspheres prepared by dispersion, suspension, or emulsion polymerization. In this study, we investigated, in detail, physicochemical properties, thermal responses, and electrooptical responses of the microspheres possessing liquid crystalline abilities. The ferroelectric liquid crystalline monomer OBBM had a thermotropic liquid crystalline ability, two‐phase transition temperatures, and a Smectic C* texture, which is characteristic of ferroelectric liquid crystalline substances. The microspheres prepared also exhibited a liquid crystalline ability, and the phase‐transition temperatures toward the liquid crystalline segments into the microspheres prepared by copolymerizing the liquid crystalline and styrene monomers could be decreased with increasing of the styrene monomer. Furthermore, we found that the microspheres remarkably exhibited electrooptical responses at about 8 V. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2490–2499, 2001     

Liquefaction of palm kernel shell to bio-oil using sub- and supercritical water: An overall kinetic study

Palm kernel shell was liquefied using sub- and supercritical water at 330–390 °C and 25 MPa for different reaction times. The overall kinetics of the liquefaction based on the conversion of biomass was analyzed using kinetic equation adopted from the literature, and the kinetic parameters were estimated from the evaluation of the kinetic equation. In this study, the rate constant (k) increased from 0.43 to 0.49 s^?1 with reaction temperature from 330 to 390 °C. The relationship of rate constant (k) and temperature agreed reasonably well with the Arrhenius equation. The activation energy (E) and pre-exponential factor (A) values for the liquefaction process were estimated to be 6.70 kJ/mol and 1.65 s^?1, respectively. In addition, the experimental bio-oil yields with respect to reaction time were well-fitted using the modified Reverchon-Sesti Osseo equation.