Investigation of reduction in etch rate of isolated holes in SiOCH

The reduction in the etch rate of isolated holes in SiOCH was investigated as functions of deposition condition of SiOCH, cap-layer presence, air-exposure time between lithography and etching, and degassing time between cap-layer etching and SiOCH etching. The amount of H₂O in the films was evaluated using thermal-desorption spectroscopy (TDS). We conclude that the H₂O adsorbed in SiOCH reduces the etch rate, and its degassing results in recovery of etch-rate reduction. Using the SiOCH film that can avoid the damage due to cap-layer deposition, the reduction in etch rate was restricted during two months of air exposure.     

Removal of hazardous phenols by microalgae under photoautotrophic conditions

Various algae were screened for their ability to decrease the concentration of 2,4-dinitrophenol (DNP), as a model compound of hazardous phenols, under photoautotrophic conditions. Chlorella fusca var. vacuolata and Anabaena variabilis grew well and showed high DNP removal ability over the concentration range of 5 to 40 microM. Their abilities to remove various phenols were investigated. More than 90% of 40 microM o- and m-nitrophenol and DNP was removed during the cultivation period of 5 d. o-, p-Chlorophenol and 2,4-dichlorophenol could be removed, but not to a significant extent. C. fusca also removed 85% of bisphenol A, suspected to be an endocrine disrupter. It was found that microalgae would be applicable to the removal of hazardous phenols without the addition of any organic carbon sources.     

Biosynthetic Gene Cluster for Surugamide A Encompasses an Unrelated Decapeptide,Surugamide F

Genome mining is a powerful method for finding novel secondary metabolites. In our study on the biosynthetic gene cluster for the cyclic octapeptides surugamides A–E (inhibitors of cathepsin B), we found a putative gene cluster consisting of four successive non‐ribosomal peptide synthetase (NRPS) genes, surA, surB, surC, and surD. Prediction of amino acid sequence based on the NRPSs and gene inactivation revealed that surugamides A–E are produced by two NRPS genes, surA and surD, which were separated by two NRPS genes, surB and surC. The latter genes are responsible for the biosynthesis of an unrelated peptide, surugamide F. The pattern of intercalation observed in the sur genes is unprecedented. The structure of surugamide F, a linear decapeptide containing one 3‐amino‐2‐methylpropionic acid (AMPA) residue, was determined by spectroscopic methods and was confirmed by solid‐phase peptide synthesis.     

Terretonin biosynthesis requires methylation as essential step for cyclization

Unexpected methylation: Terretonin is a fungal meroterpenoid derived from 3,5-dimethylorsellinic acid (DMOA). Trt1 is a terpene cyclase involved in terretonin biosynthesis and only accepts the methylated compound as a substrate to produce the cyclized product. Methylation is a common requirement for the cyclization steps in DMOA-derived meroterpenoid biosynthesis.     

Modeling of the yoke-magnetization in MFL-testing by finite elements

The yoke-magnetization is very popular in magnetic particle testing of welds. The detectability of a flaw by using this method largely depends on the magnetic flux density passing through a specimen to be examined or on the intensity of magnetic field acting in/on the specimen. In Japan inspectors have to check and confirm the appropriate magnetizing situation of the specimen by using an A-type standard test specimen specified in the standard JIS G 0565-1992. The development of indications by magnetic particles on the standard specimen is influenced by the air gap between the standard specimen and the specimen surface to be examined. Since the height and breadth of an artificial flaw in the standard specimen also influence the leakage of the magnetic flux density from the flaw, the information about the magnetizing situation is complex.In this paper we first identify influences of some factors on the magnetic leakage flux density from an artificial flaw in the standard specimen by using FEM modeling. Since the check with the standard specimen gives not a unique information to the magnetization state we investigate the technique, in which intensity of magnetic field acting on the specimen surface is used to characterize the magnetization. A finite element approach is applied to model the magnetization situation. The effectiveness of the modeling is confirmed by an experiment.     

Evaluation of standard impulse voltage/current measuring systems in Japan

A national‐standard‐class impulse voltage measuring system in Japan was developed in the consignment research of the Ministry of Economy, Trade and Industry (METI) and New Energy and Industrial Technology Development Organization (NEDO) from 1998 to 2006. The standard measuring system for the impulse voltage measurements is managed by the Japan High Voltage Impulse Testing Laboratories Liaison (JHILL) established under the Japan Electric Machine Industry Association (JEMA). The standard impulse voltage measuring system calibrates other measuring systems and assesses their uncertainties, and, therefore, its uncertainty needs to be evaluated independently. The principal components of the system are a voltage divider, a digital recorder, and a low‐voltage calibrator which generates impulse voltages of known peak voltages and waveforms. Moreover, a reference measuring system for impulse current in Japan was also developed in 2009 supported by JEMA. Its international compatibility was confirmed through an international comparison test. Through domestic comparison tests, traceability among transducers of impulse current in Japan was established. In this paper, the constitution of these measuring systems, their performance, and related latest activities, such as comparison tests, are described. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

The Oxidation of Equol by Tyrosinase Produces a Unique Di-ortho-Quinone: Possible Implications for Melanocyte Toxicity

Equol (7-hydroxy-3-(4′-hydroxyphenyl)-chroman, EQ), one of the major intestinally derived metabolites of daidzein, the principal isoflavane found in soybeans and most soy foods, has recently attracted increased interest as a health-beneficial compound for estrogen-dependent diseases. However, based on its structure with two p-substituted phenols, this study aimed to examine whether EQ is a substrate for tyrosinase and whether it produces o-quinone metabolites that are highly cytotoxic to melanocyte. First, the tyrosinase-catalyzed oxidation of EQ was performed, which yielded three EQ-quinones. They were identified after being reduced to their corresponding catechols with NaBH₄ or L-ascorbic acid. The binding of the EQ-quinones to N-acetyl-L-cysteine (NAC), glutathione (GSH), and bovine serum albumin via their cysteine residues was then examined. NAC and GSH afforded two mono-adducts and one di-adduct, which were identified by NMR and MS analysis. It was also found that EQ was oxidized to EQ-di-quinone in cells expressing human tyrosinase. Finally, it was confirmed that the EQ-oligomer, the EQ oxidation product, exerted potent pro-oxidant activity by oxidizing GSH to the oxidized GSSG and concomitantly producing H₂O₂. These results suggest that EQ-quinones could be cytotoxic to melanocytes due to their binding to cellular proteins.     

High-speed and high-backdrivable actuation system considering variable-structured elastic design

This paper proposes a high-speed high-backdrivable actuator using a new actuation structure. To realize a small-sized high-torque actuator, a reduction gear is usually used. Because of the current saturation and friction effect of the actuator, the actuator has maximum values of acceleration and rotation speed. A gear with a high gear ratio reduces these two maximum values because of the presence of a reduction mechanism. The trade-off between the output torque and rotation speed exists. Consequently, it is difficult to achieve high-speed motions using a gear. Moreover, the reduction mechanism increases the friction of the motor and deteriorates its backdrivability. Therefore, in this study, a new actuation mechanism is utilized to solve such problems. The new mechanism consists of an electromagnetic clutch and elastic spring. High backdrivability and high-speed motion are achieved by releasing the clutch and transforming the elastic potential energy accumulated by the geared motor into kinetic energy, respectively. In the proposed system, the output rotation speed exceeds the maximum rotation speed obtained after it is reduced by the gear. Finally, the validity of the proposed method is verified experimentally.     

On the sliding and profile of a liquid droplet on a rotating disk

This theoretical and experimental study was conducted to investigate the critical condition at which a liquid droplet starts to move on a rotating disk. The critical rotational speed ω was theoretically calculated based on the force balance between the surface tension and the centrifugal force, where ω was experimentally measured for each combination between three kinds of test plates and test liquids. The movements of droplets were judged from the careful observation of infinitesimal motion of the three‐phase contact line. The calculated rotational speeds agreed well with measured ones for arbitrary contact angle when the droplets were set on the plate. The three‐dimensional surface profiles of droplets were calculated from the approximate Laplace equation in which the contact line was assumed as the combination of two ellipses with different ratio of measure to minor axis. The measured profiles on the rotating disk were approximated well by the method proposed in this study. © 2009 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20276     

High throughput and exhaustive analysis of diverse lipids by using supercritical fluid chromatography-mass spectrometry for metabolomics

We have developed an analytical system that enables the simultaneous rapid analysis of lipids with varied structures and polarities through the use of supercritical fluid chromatography-mass spectrometry (SFC-MS). The separation conditions for SFC (column, modifier, back pressure, etc.) and the detection conditions for mass spectrometry (ionization method, parameters, etc.) were investigated to develop a simultaneous analytical method for lipid mixtures that included phospholipids, glycolipids, neutral lipids, and sphingolipids. When cyanopropylated silica gel-packed column was used for the separation, all lipids were successfully detected and the analysis time was less than 15 min. The use of an octadecylsilylated column resulted in separation, which was dependent on the differences in the unsaturation of the fatty acid side chains and isomer separation. This system is a powerful tool for studies on lipid metabolomics because it is useful not only as a fingerprinting method for the screening of diverse lipids but also for the detailed profiling of individual components.