Fermentation-induced changes in the concentrations of organic acids,amino acids,sugars, and minerals and superoxide dismutase-like activity in tomato vinegar

Various raw materials are used to produce vinegars that contain functional compounds associated with disease prevention. We evaluated changes in functional compounds during tomato vinegar production and superoxide dismutase-like activity of tomato vinegar. Tomato vinegar contained abundant anti-hypertensive compounds, e.g., γ-aminobutyric acid and potassium derived from tomatoes and acetic acid and pyroglutamic acid produced during fermentation. It had stronger superoxide dismutase-like activity than commercial vinegars because of tomato-derived superoxide dismutase-like compounds, including phenolic acids, flavonoids, and glutathione. These data indicate that tomato vinegar is a candidate dietary supplement with potential preventive effects against cardiovascular diseases due to its anti-hypertensive and superoxide dismutase-like compounds.     

Ultra-precision cryogenic machining of viscoelastic polymers

Microfluidic chips with micro- or nanoscale channels are currently in great demand. PDMS (polydimethylsiloxane), a viscoelastic polymer, has high transparency and good chemical stability, making it a suitable substrate material for such chips. However, it is difficult to machine PDMS by conventional cutting processes because of its high elasticity and adhesion. We proposed the cryogenic micromachining of PDMS completely immersed in liquid nitrogen as a direct process to fabricate customized 3D nano/microfluidic chips precisely. In this study, the feasibility of ultra-precision cryogenic machining is studied as an extended nanofabrication process.     

Optical tunneling effect calculation of a solid immersion lens for use in optical disk memory

A solid immersion lens (SIL) has the advantage of easily decreasing the spot size for high data density in optical recording. To accurately obtain the optical tunneling effect for a high-N.A. SIL, we calculated the optical tunneling beam characteristics, using electromagnetic theory. Tunneling beam spot-size dependence on polarization direction and energy-transfer efficiency are also clearly shown.     

Molecular mechanics and molecular orbital simulations on specific interactions between peroxisome proliferator-activated receptor PPARalpha and plasticizer

Peroxisome proliferator-activated receptor α (PPARα) has various physiological functions such as lipid and glucose metabolism, inflammation and fibrosis in living organisms. Many types of ligand molecules such as phthalate and adipate esters control these physiological functions. In the present study, to elucidate the dependence of PPARα properties on ligand binding, we investigated stable structures and electronic properties for the complexes of PPARα and phthalate as well as adipate esters, which are used as a plasticizer, by molecular simulations based on molecular mechanics and molecular orbital methods. Furthermore, to elucidate the influence of these esters in vivo, we injected them into male mice and observed the change in the expression of PPARα-related enzymes. The comparison between the calculated and observed results indicates that the change in the expression has a correlation with the size of energy gaps between highest occupied and lowest unoccupied molecular orbitals of the complexes with mouse PPARα and esters.     

Simulations of construction learning for neuron-computer resources

It is well known that information processing in the brain depends on neuron systems. Simple neuron systems are neural networks, and their learning methods have been studied. However, we believe that research on large-scale neural network systems is still incomplete. Here, we propose a learning method for millions of neurons as resources for a neuron computer. The method is a type of recurrent path-selection, so the neural network objective must have nesting structures. This method is executed at high speed. When information processing is executed by analogue signals, the accumulation of errors is a grave problem. We equipped a neural network with a digitizer and AD/DA (Analogue Digital) converters constructed of neurons. They retain all information signals and guarantee precision in complex operations. By using these techniques, we generated an image shifter constructed of 8.6 million neurons. We believe that there is the potential to design a neuron computer using this scheme. This work was presented in part at the Fifth International Symposium on Artificial Life and Robotics, Oita, Japan, January 26–28, 2000     

Characterization of neutron field in the experimental fast reactor JOYO for fuel and structural material irradiation test

The experimental fast reactor JOYO has been operated as an irradiation test facility for fast reactor fuel and structural material since 1983 with its MK-II core. During this time, an extensive study was conducted to characterize the neutron field in order to assure the accuracy and reliability of neutron fluence. Neutron flux for a given irradiation test was calculated using a core management code system based on three-dimensional diffusion theory. It was then corrected with the adjusted neutron spectrum by means of the multiple foil activation method. The neutron fluence calculation accuracy in the fuel region was evaluated within a 5% error by comparing the burn-up of spent fuel with the measured values, which had been obtained from their post-irradiation examination. At positions away from the fuel region, the neutron flux distribution was calculated using a two-dimensional transport code. A Monte Carlo code was also used to analyze the detailed neutron flux distribution within an irradiation test subassembly that had a heterogeneous internal structure. With the neutron flux results various irradiation parameters, such as displacement per atom (dpa) and helium production, could be evaluated. A helium accumulation fluence monitor has been developed to measure not only neutron fluence but also helium production. Neutron flux and fluence obtained from the core management calculations were compiled as a database for users’ convenience together with related irradiation information and fuel subassembly material compositions. These data are expected to be widely used in the post-irradiation analysis of fuel and structural material.     

Cholesterol synthesis and degradation in normal rats fed a cholesterol-free diet with excess cystine

Feeding a diet with excess cystine to rats resulted in hypercholesterolemia. To understand the mechanism of the hypercholesterolemia’ cholesterol synthesis and degradation’ bile acid content of bile’ and fecal steroids were determined. The in vivo incorporation of tritiated water into hepatic cholesterol’ and activity of hepatic 3-hydroxy-3-methylglutaryl-CoA reductase in rats fed a high-cystine diet were significantly higher than those in rats fed a control diet. The activity of hepatic cholesterol 7α-hydroxylase was similar between two groups. Little effect of cystine supplementation was found on fecal sterol excretion although there were some changes in biliary excretion of cholic acid derivatives. These results indicate that hypercholesterolemia caused by feeding of a high-cystine diet may be due to the stimulation of hepatic cholesterol synthesis.     

Truncated chlorophyll antenna size of the photosystems—a practical method to improve microalgal productivity and hydrogen production in mass culture

Unicellular microalgae hold the promise of commercial exploitation in mass culture for hydrogen and biomass production. In any microalgal production system, the achievable photosynthetic productivity and light utilization efficiency of the algae are the single most important factors in the determination of cost. Microalgal mass cultures growing under full sunlight have a low per chlorophyll (Chl) productivity since, at high photon flux densities, the rate of photon absorption by the Chl antenna far exceeds the rate at which photons can be utilized for photosynthesis. Excess photons are dissipated as fluorescence or heat. Up to 80% of absorbed photons could thus be wasted, reducing light conversion efficiencies and cellular productivity to fairly low levels. This shortcoming could possibly be alleviated by the development of microalgal strains with a limited number of Chl molecules in the light-harvesting antenna of their photosystems, i.e., strains that have a truncated Chl antenna size. It is expected that individually, such microalgae will not be able to saturate rates of photosynthesis and, thus, will not be subject to wasteful dissipation of excitation energy. In turn, the productivity of the mass culture will be improved. The method of choice to reach the objective of a “truncated light-harvesting Chl antenna” size (tla) employed DNA insertional and chemical mutagenesis of the unicellular green algae Chlamydomonas reinhardtii and Dunaliella salina, followed by a rigorous screening protocol to identify mutants with a smaller light-harvesting Chl antenna size. Molecular and genetic analyses of isolated tla strains were performed. Biochemical and physiological analyses in terms of photosynthetic productivity and light conversion efficiencies are presented. The results show that a truncated Chl antenna size of PSII is more important than that of PSI in terms of the photosynthetic productivity of a mass culture. A list of genes that confer a “truncated light-harvesting Chl antenna” size to green algae is being compiled for future application in algal hydrogen and biomass production.     

Numerical and experimental analysis of transient state micro-bounce of aerostatic guideways caused by small pores

Aerostatic guideways have been applied to precision machine elements. Recently, downsizing and the increased use of high-density technology in IT devices have generated demand for higher accuracy in aerostatic guideways. It has been pointed out that the micro-bounce occurs when the slider passes over the aerostatic guideway with small pores. This transient state micro-vibration decreases the accuracy of aerostatic guideways and, thus, it is now expected to be suppressed. The purpose of this study is to analyze the micro-bounce mechanism of aerostatic guideways caused by pores, and to propose new designs for the suppression of micro-bounce.     

Effect of the composition on the phase size in immiscible blends with the viscosity ratio close to unity

The influence of the composition and interfacial tension on the phase size in immiscible polymer blends with a viscosity ratio close to unity has been investigated with poly(methyl methacrylate)/poly(ethylene terephthalate) blends and data from various works. For all the blends considered, the dispersed particle diameter (d) is proportional to the interfacial tension of the system. When the dispersed‐phase content (?) is below 1%, there is minimal change of d with increasing ?. When ? is between 1 and 20%, d is proportional to ?^0.4. It seems that the processing conditions do not influence the morphology significantly for blend systems with a viscosity ratio close to unity.© 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1791–1799, 2003