On listing,sampling, and counting the chordal graphs with edge constraints

We discuss the problems to list, sample, and count the chordal graphs with edge constraints. The objects we look at are chordal graphs sandwiched by a given pair of graphs where we assume that at least one of the input graphs is chordal. The setting is a natural generalization of chordal completions and deletions. For the listing problem, we give an efficient algorithm running in polynomial time per output with polynomial space. As for the sampling problem, we give two clues that indicate that a random sampling is not easy. The first clue is that we show #P-completeness results for counting problems. The second clue is that we give an instance for which a natural Markov chain suffers from an exponential mixing time. These results provide a unified viewpoint from algorithms’ theory to problems arising from various areas such as statistics, data mining, and numerical computation.     

Layout optimization method for magnetic circuit using multistep utilization of genetic algorithm combined with design space reduction

Layout optimization with ON/OFF information of magnetic material in finite elements is one of the most attractive tools in the initial conceptual and practical design of electrical machinery for engineers. Heuristic algorithms based on random search allow engineers to define general‐purpose objects. However, there are many iterations of finite element analysis, and it is difficult to achieve a practical solution without island and void distribution by using a direct search method, such as simulated annealing (SA), genetic algorithm (GA), and so on. This paper presents a layout optimization method based on GA. The proposed method can arrive at a practical solution by means of multistep utilization of the GA, and the convergence speed is considerably improved by using it in combination with reduction of the design space. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 181(3): 19‐30, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22290     

Transcriptional Induction of Metallothionein by Tris(pentafluorophenyl)stibane in Cultured Bovine Aortic Endothelial Cells

Vascular endothelial cells cover the luminal surface of blood vessels and contribute to the prevention of vascular disorders such as atherosclerosis. Metallothionein (MT) is a low molecular weight, cysteine-rich, metal-binding, inducible protein, which protects cells from the toxicity of heavy metals and active oxygen species. Endothelial MT is not induced by inorganic zinc. Adequate tools are required to investigate the mechanisms underlying endothelial MT induction. In the present study, we found that an organoantimony compound, tris(pentafluorophenyl)stibane, induces gene expression of MT-1A and MT-2A, which are subisoforms of MT in bovine aortic endothelial cells. The data reveal that MT-1A is induced by activation of both the MTF-1–MRE and Nrf2–ARE pathways, whereas MT-2A expression requires only activation of the MTF-1–MRE pathway. The present data suggest that the original role of MT-1 is to protect cells from heavy metal toxicity and oxidative stress in the biological defense system, while that of MT-2 is to regulate intracellular zinc metabolism.     

污水硫自养反硝化技术研究进展

硫自养反硝化（SAD）是一种绿色低碳的污水脱氮技术,具有成本低、污泥产量少、无须外加有机碳源等优点,已成为污水脱氮技术研究的热点之一。阐述SAD填料组成与复合硫源填料的合成方法,归纳SAD固定床反应器和流化床反应器的结构及其适用条件,回顾SAD与电化学、异养反硝化、厌氧氨氧化耦合工艺等方面的研究进展,并总结SAD耦合技术的优缺点以及耦合工艺的脱氮特征。微生物的代谢功能是实现高效SAD的关键因素,列举不同代谢特性的SAD功能微生物种类,阐述代表性微生物Thiobacillus和Sulfurimonas在SAD过程中的反硝化特性及其生长条件。目前,SAD技术在填料、反应器和耦合工艺等方面取得显著进步,但仍面临诸多挑战,在SAD技术温度适应性、高处理负荷反应器设计以及工艺流程优化等方面进一步创新。     

Origin of common-mode noise in two-dimensional finite-size circuit and reduction of the noise using a symmetric three-line circuit

In this paper, we investigate common-mode (CM) noise caused by a connection to a two-dimensional finite-size ground plane. Numerical calculations are conducted to visualize the time variation of potentials that leads to CM noise. A connection of the signal line to the ground plane, which is conventionally used in circuits, causes an imbalance in the circuit that makes the potential of the ground plane fluctuate, which results in CM noise. CM noise does not occur in a symmetric three-line circuit because the potential of the middle line is always kept at 0 V. Furthermore, the middle line prevents an externally induced potential fluctuation of the ground plane from being converted to a normal-mode voltage (i.e., CM noise).     

Prediction of particle charging in a dilute pneumatic conveying system

When particles are transported in pipelines, they acquire electrostatic charges as they come into contact with the pipe wall. Charged particles can cause problems such as particle agglomeration, blockage, and explosion. Understanding the particle charge can help to prevent these issues. This study investigates a technique for predicting the particle charge in a straight pipe of any given length, as well as the pipe length at which electrostatic equilibrium occurs, through experimentation in a short 1‐m pipe section. Experimentation with five different types of particles and four pipe wall materials at longer pipe lengths were used to validate the technique. This predictive technique is applicable to a range of particle shapes and sizes under the restriction that charge transfer is due to impact charging. © 2013 American Institute of Chemical Engineers AIChE J, 59: 2308–2316, 2013     

Oxidation kinetics of linoleic acid in the presence of saturated acyl <Emphasis Type="SmallCaps">l</Emphasis>-ascorbate

The oxidation processes of linoleic acid (LA) in the presence of l-ascorbic acid or saturated acyl l-ascorbate additives were measured at various temperatures and molar ratios of the additive to LA. Higher oxidative stability of LA was observed at higher additive levels for all additives. The addition of the ascorbates lengthened the induction period for the oxidation of LA. An autocatalytic kinetic rate equation was used to model the oxidation processes of LA mixed with the ascorbates, and the dependence of the rate constant, k, on acyl-chain carbon number was determined. At any temperature, the use of ascorbate additives decreased the k value for LA, and there was a slight tendency for k values to decrease with increasing acyl-chain length. The apparent activation energy, E _a, and the frequency factor, k ₀, for the rate constant were determined from Arrhenius plots. The calculated E _a and k ₀ values also decreased with increasing ascorbate acyl-chain length.     

Fatty acids in must prepared from 11 grapes grown in Japan: Comparison with wine and effect on fatty acid ethyl ester formation

FA components of 11 mustsmade from grape cultivars grown for making red wine in various regions of Japan and of wines made from the musts were compared to elucidate variety-dependent characteristics and to clarify their effect on FA ethyl ester (FAEE) formation in wine. Sixteen FA with carbon chain lengths from 12 to 26 were detected in all musts, with palmitic, linoleic, and linolenic acids generally predominating. Higher levels of linoleic acid were found in musts from a cold region (Hokkaido), and higher levels of oleic acid occurred in musts from a warm region (Honshu). Moreover, the unsaturation indexes (1.31–1.56) of five grape musts from the cold region showed significant differences among varieties, corresponding to the grapevines’ degree of cryotolerance. The FA levels (610–6,610 nmol/100 mL) of all wines were extremely low (1.2–12.8%) compared with those of must, but the FA compositions were similar to those of must. Additionally, significant amounts of FAEE, possibly derived from yeast activity, were found in wines by using a solid-phase extraction method. The amounts of FAEE in wine significantly differed among samples (245–904 nmol/100 mL) and were inversely correlated with the percentage of linoleic acid in musts (R=−0.883). Thus, higher linoleic acid levels in must may be related to lower FAEE formation by yeast.     

Properties of gels obtained by freezing/thawing of poly(vinyl alcohol)/water/dimethyl sulfoxide solutions

Melting points of poly(vinyl alcohol) (PVA) gels obtained by repeated freezing/thawing cycles of the solutions in mixed solvents of water and dimethyl sulfoxide (DMSO) were measured. PVA solutions in 1–30 and 90 vol % DMSO froze at ?40°C. The melting point of a gel increased with an increase in freezing/thawing cycles for all the solutions frozen and with an increase in freezing time in 10–30 vol % DMSO. The solutions in 1–5 vol % DMSO gelled even at very low polymer concentration of 1.0 g/dL by repeated freezing/thawing. The melting point of all the gels with a 5% polymer concentration reached ca. 73°C after 14 freezing/thawing cycles except for the gels in 90 vol % DMSO. However, the melting point of the gels with the same polymer concentration prepared at ?40°C using an unfrozen mixed solvent in 60 vol % DMSO was ca. 77°C and the largest. The maximum apparent enthalpy of fusion of the gels prepared by repeated freezing/thawing was ca. 40 kcal/mol. The gels in 90 vol % DMSO were transparent independent of cycles where as those in 1–80 vol % DMSO were opaque. The degree of opaqueness increased with decreasing DMSO content.     

Preparation of Hydrogen Permeable Membrane Using Nanoparticles Electrophoresis Technique

Hydrogen perm-selective membranes composed of Pd nanoparticles were investigated. The nanoparticles were prepared by ultrasonic reduction from Pd^II ions, and then deposited on a substrate disc with electrophoresis technique. These electrophoretic membranes have shown high performance of perm-selectivity for H₂ with separation factor α = 3.85, under room temperature.