Contribution of adsorptive or acid–base interaction between phenol molecules and polyvinylpyridine membrane to the large permeability of phenol through the membrane

Permeability of phenol from aqueous solution to organic solvent through a microporous membrane made of cross-linked poly (4-vinylpyridine) (polyvinylpyridine membrane) was about 12 times larger than that through a microporous membrane made of polyethylene (polyethylene membrane) having similar thickness, porosity, and mean pore diameter with those of polyvinylpyridine membrane. Adsorptive or acid–base interaction between phenol molecules and polyvinylpyridine membrane was shown to play an important role in this unusally rapid permeation of phenol through the membrane. The amount of phenol contained in polyethylene membrane per unit volume of the pores was about six times larger than the phenol concentration in the feed aqueous solution. However, the amount of phenol contained in polyvinylpridine membrane per unit volume of the pores was 80–260 times larger than the feed phase concentration. The rapid permeation of phenol through poly-vinylpyridine membrane was thus explained in terms of the extensive enrichment of phenol in the membrane due to the adsorptive or acid–base interaction between phenol molecules and the membrane. © 1993 John Wiley & Sons, Inc.     

Graft polymerization of acrylic acid onto polyethylene film by preirradiation method. II. Effects of oxygen at irradiation,storage time after irradiation,mohr's salt,and ethylene dichloride

In the grafting of acrylic acid onto polyethylene by preirradiation method, the irradiation in air gave a higher rate of grafting than in N₂, since the diffusion rate of monomer is larger for less crosslinked polyethylene. The rate of grafting decreased with increasing time of storaging polyethylene because of the decay of trapped radicals. The effects of storage conditions on the grafting activity was reasonably interpreted by assuming that grafting is predominantly controlled by both concentration of trapped radicals and monomer diffusibility in the polymer matrix. Mohr's salt was found to depress the homopolymerization of acrylic acid without marked change of grafting rate. The rate of grafting was increased by the addition of ethylene dichloride due to the increase in monomer diffusion.     

Formation and Transformation of WO3 Prepared from Alkoxide

Amorphous WO₃ or WO₃ or H₂O is formed by hydrolysis of tungsten ethoxide. The temperature of hydrolysis influences the crystallization of WO₃·H₂O. Tungsten hydrate (WO₃·H₂O) has an orthorhombic unit cell with a=0.5235 nm, b = 1.0688 nm, and c=0.5123 nm. Orthorhombic WO₃ crystallizes at 350° to 500°Cfrom amorphous WO₃. Cubic WO₃ is formed at 200° to 310°C with dehydration of WO₃·H₂O. WO₃ transformations are examined by high-temperature X-ray diffraction. The kinetics of formation of the cubic modification have been studied by measuring the weight decrease with a thermobalcnce. Formation isotherms can be interpreted in terms of the first-order equation –In (1–f)=kt; activation energies are 110 and 80 kJ mol⁻¹ for initial and final stages, respectively.     

X-ray crystallographic data on aluminum silicon carbide, α-Al4SiC4 and Al4Si2C5

Single-crystal and powder X-ray crystallographic data on -Al₄SiC₄ and Al₄Si₂C₅ are given, and their respective space groups are P6₃ mc and R¯3m. Powder X-ray diffraction lines are individually indexed in the 2-range from 5° to 110°. The unit cell dimensions obtained from a least-square computer program are a=3.2771 Å (±0.0001 Å), c= 21.676 Å (±0.002) for -Al₄SiC₄ and a=3.2512 Å (±0.0002 Å), c=40.1078 Å (±0.0027 Å) for Al₄Si₂C₅. In addition, it is proposed that the crystal structures of -Al₄SiC₄ and Al₄Si₂C₅ may be formed by substituting SiC-layers for AIN-layers in the Al₅C₃N and Al₆C₃N₂ structures.     

Melting and crystallization behavior of poly(tetrafluoroethylene). New method for molecular weight measurement of poly(tetrafluoroethylene) using a differential scanning calorimeter

Melting and crystallization behavior of virgin polytetrafluoroethylene have been studied using a differential scanning calorimeter. Following quantitative relationship was found between number average molecular weight of polytetrafluoroethylene and the heat of crystallization in the molecular weight range of 5.2 × 10⁵ to 4.5 × 10⁷: M?_n = 2.1 × 10¹⁰ ΔH_c^?5.16, where M?_n is number average molecular weight and ΔH_c is the heat of crystallization in cal/g. The heat of crystallization is independent of cooling rate ranging from 4 to 32°C/min. This relationship provides a simple rapid and reliable method for measuring the molecular weight of polytetrafluoroethylene.     

Citrus auraptene exerts dose-dependent chemopreventive activity in rat large bowel tumorigenesis: the inhibition correlates with suppression of cell proliferation and lipid peroxidation and with induction of phase II drug-metabolizing enzymes

In our previous short-term experiment, Citrus auraptene inhibited the development of azoxymethane (AOM)-induced aberrant crypt foci, which are precursor lesions for colorectal carcinoma. In the present study, the possible inhibitory effect of dietary administration of auraptene was investigated using an animal colon carcinogenesis model with a colon carcinogen AOM. Male F344 rats were given s.c. injections of AOM (15 mg/kg body weight) once a week for 3 weeks to induce colon neoplasms. They also received diets containing 100 or 500 ppm auraptene for 4 weeks in groups of "initiation" feeding, starting 1 week before the first dosing of AOM. The diets containing auraptene were also given to rats for 38 weeks in groups of "postinitiation" feeding. At the termination of the study (38 weeks), dietary administration of auraptene caused dose-dependent inhibition in AOM-induced large bowel carcinogenesis. Auraptene feeding during the initiation phase reduced the incidence of colon adenocarcinoma by 49% at 100 ppm (P = 0.099) and 65% at 500 ppm (P = 0.0075). Auraptene administration during the postinitiation phase inhibited the incidence of colon adenocarcinoma by 58% at 100 ppm (P = 0.021) and 65% at 500 ppm (P = 0.0075). Also, the multiplicity of colon carcinoma was significantly reduced by initiation feeding at a dose level of 500 ppm (P < 0.01) and postinitiation feeding at a level of 100 and 500 ppm (P < 0.05 and P < 0.01, respectively). Feeding of auraptene suppressed the expression of cell proliferation biomarkers (ornithine decarboxylase activity and polyamine content) in the colonic mucosa and reduced the production of aldehydic lipid peroxidation [malondialdehyde and 4-hydroxy-2(E)-nonenal]. In addition, auraptene increased the activities of Phase II drug-metabolizing enzymes (glutathione S-transferase and quinone reductase) in the liver and colon. These findings suggest that the inhibitory effects of auraptene on AOM-induced colon tumorigenesis at the initiation level might be associated, in part, with increased activity of Phase II enzymes, and those at the postinitiation stage might be related to suppression of cell proliferation and lipid peroxidation in the colonic mucosa.     

Active interaction utilizing micro mobile robot and on-line data gathering for experiments in cricket pheromone behavior

This paper describes about a prototype system for active interaction experiment to a cricket by utilizing an operated micro mobile robot. It is also able to measure/collect behavior data of the cricket on-line. The behavior selection of the cricket (Gryllus bimaculatus) is influenced by the experience or the context in living environment. In our current research, we are trying to investigate neuronal mechanisms underlying adaptive behavior switching of the cricket based on individual interactions. However in conventional biological experiments, the conditions are not maneuverable intentionally. Therefore, we are developing an integrated system for conducting active interaction experiments and gathering behavior data related to the effect of interactions. The prototype consists of a micro mobile robot as a physical interaction agent, a camera and a microphone and a computer. The computer is for commanding the robot by the operator’s input. It also works for recording the data of a video sequence, on-line motion tracking and the audio during the experiment. Interaction experiments with the cricket utilizing the prototype system were done. From the results, we could confirm it works well especially for maneuvering experimental conditions and on-line experimental data gathering.     

Cross-Cultural Perspectives on Religion and Computer-Mediated Communication

Previous research on religion and CMC has focused primarily on Christianity and the Western world. The articles collected in this special theme section of the Journal of Computer-Mediated Communication examine a wide range of religions online through both quantitative and qualitative methodologies. The Abrahamic traditions of Judaism, Christianity, and Islam, as well as Hinduism, Shinto, Taoism, Chinese traditions, animism, Japan's New Religions, and diverse forms of Buddhism are examined, in an equally wide range of national cultures and traditions: Israel, Egypt and the Arab world more broadly, India, Japan, Malaysia, Singapore, and the United States. Individually and collectively, the articles highlight shared characteristics of religion cross-culturally that foster or hinder religions' migration online—a migration that most, although not all, religions undertake in varying degrees.     

A simulation model for chemically amplified resist CAMP6

In this paper, a model for computer simulation of the exposure and the development of the CAMP6 chemically amplified resist (CAR) during electron beam lithography is proposed. The distribution of the absorbed electron energy in the exposed resist is determined using our Monte Carlo algorithm and computer programs. A wider resist de-protection region due to the diffusion of the exposure catalyst product (acid) during the post-exposure bake (PEB) is estimated. It lays a special emphasis upon the development process simulation. Experimentally obtained time dependent macroscopic characteristics of the development (contrast curves, the development rate vs. the exposure dose) are taken into account, aiming to avoid the need for further calibration. The proposed model demonstrates qualitative agreement with the development kinetics of the resist developed profiles for the studied CAR.     

Theoretical study on possible usage of difluoromethylene fullerenes as electron-transport materials

The usefulness of the difluoromethylene fullerenes C₆₀(CF₂)_n(n = 1, 2) materials for the organic devices is theoretically discussed, comparing with C₆₀, about the following three points: electron transport in the material, electron injection from the electrode into the material, and thin-film formation of the material. Concerning the thin-film formation, dipole moments are calculated. Frontier orbital energies and adiabatic electron affinities are discussed in connection with the electron injection from the electrode into the material. Additionally, the inter-molecular electron transport is discussed from the viewpoint of the reorganization energy based on the Marcus theory. These results indicate the usage of some C₆₀(CF₂)_n isomers as the useful electron-transport materials.