Photoautotrophic cultures of the host and transformed cells of Marchantia polymorpha under controlled incident light intensity

Photoautotrophic cultures of the host and transformed cells of the liverwort, Marchantia polymorpha, were examined. In cultures in flat glass flasks under various light intensities, it was found that the growth rates of both the cells increased with increase in light intensity in the range of 0 to 25 W/m2, but further increase in light intensity caused photoinhibition of the growth of the cells. Cultures of both the types of cells under light-controlled conditions using an externally illuminated bioreactor were carried out taking into consideration the inhibition of cell growth by excessive light and the light intensity distributions in the cell suspensions. In these cultures, 2.1 (transformed cells) and 3.3 (host cells) kg dry cell weight per m3 were harvested at culture times of 9.0 and 10 d, respectively. These values were larger than those obtained in cultures of the respective cells at a fixed incident light intensity of 25 W/m2.     

Effects of4He coverage on the propagation of fourth sound in superfluid3He

We report measurements on the effects of⁴He coverage and pressure on the fourth sound propagation in superfluid³He in confined geometries of four different pore sizes.     

Viscoelastic properties of epoxy resins. II. Antiplasticization in highly crosslinked epoxy system

The effect of the addition of certain low molecular weight compounds to highly crosslinked epoxy resins was investigated. The behavior which is known as antiplasticization, such as increases in modulus and yield strength and the elimination of β-transition, was observed in the highly crosslinked system as well as in the reported cases of thermoplastics—poly(vinyl chloride), bisphenol A polycarbonate, and polysulfone. Chlorinated biphenyl was found to be one of the most effective antiplasticizers examined in the present paper. However, the remarkable reduction in compressive strain at break and impact strength was not recognized for the highly antiplasticized samples. These phenomena have been interpreted on the basis of free volume concept.     

Isolation and characterization of a novel gene encoding alpha-L-arabinofuranosidase from Aspergillus oryzae

We cloned and characterized a novel gene (abfA) encoding alpha-L-arabinofuranosidase (alpha-L-AFase) from Aspergillus oryzae. One clone homologous to the alpha-L-AFase gene of Thermotoga maritima was found in an expressed sequence tag (EST) library of A. oryzae and a corresponding gene was isolated. Molecular analysis showed that the abfA gene carried six exons interrupted by five introns and had an open reading frame encoding 481 amino acid residues. The amino acid sequence similarity at active sites to the alpha-L-AFases from other organisms indicated that the alpha-L-AFase encoded by abfA was classified as a family 51 glycoside hydrolase. When the abfA was overexpressed in the homologous hyperexpression system of A. oryzae, a large amount of alpha-L-AFase was produced as intracellular protein. The apparent molecular mass of the purified enzyme was estimated to be 228,000 by gel filtration and that of its subunit as 55,000 by SDS-PAGE, suggesting that the enzyme is a tetramer. The enzyme hydrolyzed p-nitrophenyl-alpha-L-arabinofuranoside but not other p-nitrophenyl glycosides. These results demonstrated that the abfA gene encodes a functional alpha-L-AFase.     

Dendrimer-immobilized culture surface as a tool to evaluate formation of cellular cytoskeleton of anchorage-dependent cells

Anchorage-dependent cultivation of human epithelial and keratinocyte cells was carried out on surfaces modified with synthesized dendrimers. Notable elongation of the epithelial cells was recognized on the culture surface immobilized with a dendrimer having D-glucose as a functional ligand, but not when a dendrimer having L-glucose was used or when the dendrimer was ligand-free. This morphological change was attributable to a temporary grasping of the cells at the D-glucose moiety via a glucose transporter-mediated mechanism present in the cell membrane. Following visualization of the actin filaments of the cells, it was considered that the cellular elongation on the D-glucose-bound dendrimer surface reflected the degree of formation of the cellular cytoskeleton. The cellular roundness was calculated by means of image analysis of the individual cells and employed as a parameter to evaluate the formation of the cellular cytoskeleton. In the culture of keratinocytes on the D-glucose-bound dendrimer surface, it was demonstrated that the decrease in the ratio of elongated cells (i.e., cells with a low roundness value) was correlated with the deterioration in the growth potential associated with cellular senescence.     

Resonance Effect on the Tunneling Reaction: H+H2→H2+H in Solid Hydrogen

The tunneling abstraction reaction: H+H₂H₂+H in -irradiated solid hydrogen has been studied using electron spin resonance (ESR) and electron-nuclear double resonance (ENDOR) spectroscopy and gas-chromatography. The rate constant for the tunneling reaction in solid hydrogen was found to decrease with the increase in the concentration of ortho-H₂ molecules in solid hydrogen. We concluded that the decrease in the rate constant is due to the energy level mismatching between reactant species of H+H₂ trapped and product species of H₂+H trapped in the reverse induced by inhomogeneous intermolecular interactions between ortho-H² molecules in solid hydrogen. This result indicates that resonance effects play an important role in tunneling reactions in solids.     

Switching Phenomena between Laminar and Turbulent Flows of Superfluid 4He Generated by a Vibrating Wire

We have investigated the turbulence transition of the superfluid ⁴He flow generated by a vibrating wire. For a 1.2-kHz vibrating wire, we observed intermittent switchings between laminar and turbulent flows. The switching rate decreases with increasing temperature above 100 mK, until no occurrence of the switchings at 350 mK. For a 2.4-kHz vibrating wire, we find that the switching rate is much lower than that of the 1.2-kHz vibrating wire even at low temperatures. This result indicates that a mechanism causing the switchings is influenced by the temperature and the oscillation frequency of the superfluid flow.     

Analytic Flow Design Method for an Automated Distribution Center with Multiple Shipping Areas

An analytic flow design algorithm for an automated distribution center with multiple shipping areas is presented. The main elements of the analytic flow design are the number of devices and the volumes of product flow between the devices. In the design of an automated distribution center, it is necessary to satisfy the demand throughput while minimizing construction costs. In the conventional design process, system engineers utilize experimental and intuitional approaches. However, conventional approaches are time-consuming and the design outcome is dependent on the skill of the designer. Therefore, a theoretical design algorithm is needed. We propose an analytic flow design algorithm using a dynamic network flow model and considering time-variable flow volumes according to shipment and storage schedules. To verify the feasibility of the proposed method, we perform analytic flow design using real data and confirm that the proposed method can yield a feasible analytic flow design in several minutes.     

Observations of bound Tween80 surfactant molecules on single-walled carbon nanotubes in an aqueous solution

The slow diffusion of Tween80 surfactant molecules in a single-walled carbon nanotube (SWCNT) aqueous dispersion was directly observed using the pulsed field gradient nuclear magnetic resonance method. The slow diffusion of Tween80 molecules was attributed to the strongly adsorbed molecules on the SWCNTs in the aqueous dispersion. The amount of bound Tween80 molecules was estimated to be approximately 12% of the total amount of Tween80 molecules, contributing to the stability of the SWCNT aqueous dispersion. Using dynamic light scattering and total organic carbon measurements, this SWCNT/Tween80 aqueous dispersion was found to be very stable for at least 3 weeks. The observed zeta potentials of this SWCNT dispersion are between −10 and 0 mV, indicating that the stability of the SWCNTs in the Tween80 solution was maintained by steric interactions between the small amount of adsorbed Tween80 molecules on the SWCNTs, while the effect of electrostatic interactions between adsorbed Tween80 was minimal. This proposed method to investigate the amount of bound Tween80 molecules on SWCNTs has potential benefits in the field of the production of functional materials and nano-toxicity assessments.