Performance improvement of JPEG2000 steganography using QIM

This paper presents a modified QIM-JPEG2000 steganography which improves the previous JPEG2000 steganography using quantization index modulation （QIM）. Since after-embedding changes on file size and PSNR by the modified QIM-JPEG2000 are smaller than those by the previous QIM-JPEG2000, the modified QIM-JPEG2000 should be more secure than the previous QIM-JPEG2000.     

Effect of microwell chip structure on cell microsphere production of various animal cells

The formation of three-dimensional cell microspheres such as spheroids, embryoid bodies, and neurospheres has attracted attention as a useful culture technique. In this study, we investigated a technique for effective cell microsphere production by using specially prepared microchip. The basic chip design was a multimicrowell structure in triangular arrangement within a 100-mm² region in the center of a polymethylmethacrylate (PMMA) plate (24 × 24 mm²), the surface of which was modified with polyethylene glycol (PEG) to render it nonadhesive to cells. We also designed six similar chips with microwell diameters of 200, 300, 400, 600, 800, and 1000 μm to investigate the effect of the microwell diameter on the cell microsphere diameter. Rat hepatocytes, HepG2 cells, mouse embryonic stem (ES) cells, and mouse neural progenitor/stem (NPS) cells formed hepatocyte spheroids, HepG2 spheroids, embryoid bodies, and neurospheres, respectively, in the microwells within 5 days of culture. For all the cells, a single microsphere was formed in each microwell under all the chip conditions, and such microsphere configurations remained throughout the culture period. Furthermore, the microsphere diameters of each type of cell were strongly positively correlated with the microwell diameters of the chips, suggesting that microsphere diameter can be factitiously controlled by using different chip conditions. Thus, this chip technique is a promising cellular platform for tissue engineering or regenerative medicine research, pharmacological and toxicological studies, and fundamental studies in cell biology.     

Effects of temperature and substrate concentration on biological hydrogen production from starch

This study investigates the effects of temperature and substrate concentration on biological hydrogen production from starch using mixed cultures. In this work, although hydrogen was successfully produced under the thermophilic condition, stable hydrogen production was not observed under the mesophilic condition. In the thermophilic reactor, the maximum hydrogen yield was 2.8 mol H₂/mol glucose at 20 g/l-starch; however, hydrogen yield decreased drastically with the change of by-product distribution when substrate concentration was over 30 g/l-starch. A negative correlation was observed between the hydrogen yield and the total concentration of undissociated acids.     

Chemical Composition of the Defensive Secretion of the Longhorned Beetle, <Emphasis Type="Italic">Chloridolum loochooanum</Emphasis>

Adults of the longhorned beetle, Chloridolum loochooanum Gressitt (Coleoptera: Cerambycidae) emit a white frothy secretion from their metasternal glands. This defensive substance contains cyclopentanoid monoterpenoids (iridodials), whose structures were elucidated by gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) analyses that compared the naturally occurring structures with synthesized versions. Optically active citronellals, [(S)-, (R)-, and (S)/(R)- mixture], were used as starting materials for synthesizing the corresponding iridodials for the determination of the absolute configuration of the natural product. The retention time of (2S)-iridodial, derived from (S)-citronellal, corresponded to that of C. loochooanum iridodial by enantioselective GC analysis. Thus, we suggest that the absolute configuration of C. loochooanum iridodial is (1R,2S,5S)-iridodial.     

Oxidation of all‐cis‐7,10,13,16,19‐docosapentaenoic acid ethyl ester. Hydroperoxide distribution and volatile characterization

The isomeric hydroperoxide distribution and the composition of volatiles generated by oxidation of all‐cis‐7,10,13,16,19‐docosapentaenoic acid ethyl ester (DPA Et) were determined. DPA Et was prepared by using seal blubber oils as raw material and purified by urea complexation and reverse‐phase high‐performance liquid chromatography (HPLC). The DPA Et of over 96% purity thus obtained was dissolved in methanol and subsequently divided into two portions. One portion was added with methylene blue and exposed to a tungsten bulb light at 5 °C for photosensitized oxidation. The other portion was added with 2,2'‐azobis (2,4‐dimethylvaleronitrile) as an azo‐radical initiator and kept in the dark at room temperature for autoxidation. Positional isomers of hydroperoxides generated by autoxidation or photosensitized oxidation of DPA Et were separated by normal‐phase HPLC and detected by a fluorescence detection system as well as UV absorption. The peak components were identified by gas chromatography‐mass spectrometry (GC‐MS). Eight isomeric hydroperoxides, including certain amounts of 7‐, 10‐, 11‐, 13‐, 14‐, 16‐, 17‐, and 20‐hydroperoxy docosapentaenoate, were generated by autoxidation of DPA Et. The photosensitized oxidation of DPA Et yielded not only the above eight hydroperoxide isomers but also two additional isomeric hydroperoxides, 8‐ and 19‐hydroperoxy docosapentaenoate, which are characteristic hydroperoxide isomers generated by singlet oxygen‐mediated oxidation. Volatiles formed by autoxidation of DPA Et at 50 °C were collected and analyzed by solid‐phase micro‐extraction and GC/GC‐MS. A number of aldehydes, ketones, alcohols, acids, furans and hydrocarbons were identified. The formation mechanisms of certain volatiles are discussed.     

A simplified model of SO2 capture by limestone in 71 MWe pressurized fluidized bed combustor

A mathematical model of SO₂ capture by uncalcined limestone particles with solid attrition under pressurized fluidized bed combustion conditions was developed based on the shrinking unreacted-core model. Since the thickness of the product layer is sufficiently much smaller than the particle size, a flat surface model was employed. The difference in SO₂ capture behavior between continuous solid attrition and intermittent attrition was investigated. The reaction rate for intermittent solid attrition was found to be lower than that for continuous attrition mode under low SO₂ concentration conditions. A simple mathematical expression to calculate reaction rate of SO₂ capture per unit external surface area of limestone is proposed.The present simplified mathematical model of SO₂ capture by single limestone particle under periodical attrition conditions was applied to the analysis of a large-scale pressurized fluidized bed combustor. By giving the period of attrition as a parameter, the experimental results agreed well with the model results. From the vertical concentration profile of SO₂ concentration, the emission of SO₂ was found to be governed by the balance between SO₂ formation rate from char and SO₂ capture by limestone at the upper surface of the dense bed. A simplified expression to estimate SO₂ emission from pressurized fluidized bed combustors was proposed.     

Biotransformation of l‐menthol by soil‐borne plant pathogenic fungi (Rhizoctonia solani)

The biotransformation of l‐menthol was investigated by using nine isolates of Rhizoctonia solani (AG‐1‐IA Rs24, Joichi‐2, RRG97‐1; AG‐1‐IB TR22, R147, 110.4; AG‐1‐IC F‐1, F‐4 and P‐1) as a biocatalyst. In the cases of Rhizoctonia solani F‐1, F‐4 and P‐1, almost all of the substrate was consumed in 3 days and the major metabolite increased rapidly for the first of 3 days incubation. The structure of the major metabolite was elucidated on the basis of its spectral data. The major metabolite was determined to be (?)‐(1S,3R,4S,6S)‐6‐hydroxymenthol which indicated that l‐menthol was hydroxylated at the C‐6 position. From the main component analysis, the nine isolates of Rhizoctonia solani were divided into two groups based on their ability to transform l‐menthol to (?)‐(1S,3R,4S,6S)‐6‐hydroxymenthol. This is the first report on the biotransformation of l‐menthol by Rhizoctonia solani. © 2001 Society of Chemical Industry     

New Preparation Method for PZT Films Using Electrochemical Reduction

PZT perovskite films on stainless steel were prepared by electrochemical reduction in solutions containing TiO²⁺, ZrO²⁺, and Pb²⁺ ions. Heat treatment at temperatures higher than about 500°C was necessary for crystallization, because the as-deposited oxide films were amorphous. The deposited oxides consisted of a mixture of hydroxides and oxide produced by an increase of pH due to some electrochemical reduction reactions of NO₃⁻, H⁺, and H₂O on the electrode surface. The composition of the PZT films was easily controlled by the composition in solution during the electrolysis. The mechanism of the PZT precursor deposition is discussed.     

A Microcomputer-Based System for Electronic Engine Control Unit Development

Making full use of microcomputers, a Universal Control Unit (UCU), Data Acquisition Unit (DAU), and Engine Simulation Unit (ESU), have been developed for an engine control development system. The UCU has been designed to perform many types of engine control. The DAU is employed to sample various data and to change the control program and characteristics data. Both units can be mounted within an automobile if necessary. The ESU simulates engine performance. The system consisting of a commercially available program design aid and personal computer, as well as these units, facilitates evaluating hardware and software of various control units, and efficiently reduces development time and cost.