State feedback stabilization of cascaded nonlinear systems with discontinuous connection

In practical engineering, many phenomena are described as a discontinuous function of a state variable, and the discontinuity is usually the main reason for the degradation of the control performance. For example, in the set-point control problem of mechanical systems, the static friction （described by a sgn function of velocity of the contacting faces） causes undesired positioning error. In this paper, we will investigate the stabilization problem for a class of nonlinear systems that consist of two subsystems with cascaded connection. We will show the basic idea with a special case first, and then the result will be extended to more general cases. Some interesting numerical examples will be given to demonstrate the effectiveness of the proposed design approach.     

Anti-Oncogenic gem-Dihydroperoxides Induce Apoptosis in Cancer Cells by Trapping Reactive Oxygen Species

Organic gem-dihydroperoxides (DHPs) and their derived peroxides have attracted a great deal of attention as potential anti-cancer agents. However, the precise mechanism of their inhibitory effect on tumors is unknown. To determine the mechanism of the inhibitory effects of DHPs, we examined the effects of DHPs on leukemia K562 cells. As a result, certain DHPs used in this study exhibited growth-inhibitory activity according to a clear structure-activity relationship. The most potent DHP, 12AC3O, induced apoptosis in K562 cells, but not in peripheral blood monocytes (PBMCs) or fibroblast cells. 12AC3O induced apoptosis through the intrinsic mitochondrial pathway and thereafter through the extrinsic pathway. The activity of the former pathway was partly attenuated by a JNK inhibitor. Interestingly, 12AC3O induced apoptosis by trapping a large amount of ROS, leading to an extremely lower intracellular ROS level compared with that in the cells in the steady-state condition. These results suggest that an appropriate level of intracellular ROS was necessary for the maintenance of cancer cell growth. DHPs may have a potential to be a novel anti-cancer agent with minimum adverse effects on normal cells.     

Interaction of inorganic arsenic with biogenic manganese oxide produced by a Mn-oxidizing fungus, strain KR21-2

In batch culture experiments we examined oxidation of As(III) and adsorption of As(III/V) by biogenic manganese oxide formed by a manganese oxide-depositing fungus, strain KR21-2. We expected to gain insight into the applicability of Mn-depositing microorganisms for biological treatment of As-contaminated waters. In cultures containing Mn2+ and As(V), the solid Mn phase was rich in bound Mn2+ (molar ratio, approximately 30%) and showed a transiently high accumulation of As(V) during the early stage of manganese oxide formation. As manganese oxide formation progressed, a large proportion of adsorbed As(V) was subsequently released. The high proportion of bound Mn2+ may suppress a charge repulsion between As(V) and the manganese oxide surface, which has structural negative charges, promoting complex formation. In cultures containing Mn2+ and As(III), As(III) started to be oxidized to As(V) after manganese oxide formation was mostly completed. In suspensions of the biogenic manganese oxides with dissolved Mn2+, As(III) oxidation rates decreased with increasing dissolved Mn2+. These results indicate that biogenic manganese oxide with a high proportion of bound Mn2+ oxidizes As(III) less effectively than with a low proportion of bound Mn2+. Coexisting Zn2+, Ni2+, and Co2+ also showed similar effects to different extents. The present study demonstrates characteristic features of oxidation and adsorption of As by biogenic manganese oxides and suggests possibilities of developing a microbial treatment system for water contaminated with As that is suited to the actual situation of contamination.     

Tea catechins modulate the glucose transport system in 3T3-L1 adipocytes

In this study, we investigated the effects of tea catechins on the translocation of glucose transporter (GLUT) 4 in 3T3-L1 adipocytes. We found that the ethyl acetate fraction of green tea extract, containing abundant catechins, most decreased insulin-induced glucose uptake activity in 3T3-L1 cells. When the cells were treated with 50 μM catechins in the absence or presence of insulin for 30 min, nongallate-type catechins increased glucose uptake activity without insulin, whereas gallate-type catechins decreased insulin-induced glucose uptake activity. (-)-Epicatechin (EC) and (-)-epigallocatechin (EGC), nongallate-type catechins, increased glucose uptake activity in the dose- and time-dependent manner, whereas (-)-catechin 3-gallate (Cg) and (-)-epigallocatechin 3-gallate (EGCg), gallate-type catechins, decreased insulin-induced glucose uptake activity in the dose- and time-dependent manner. When the cells were treated with 50 μM catechins for 30 min, EC and EGC promoted GLUT4 translocation, whereas Cg and EGCg decreased the insulin-induced translocation in the cells. EC and EGC increased phosphorylation of PKCλ/ζ without phosphorylation of insulin receptor (IR) and Akt. Wortmannin and LY294002, inhibitors for phosphatidylinositol 3'-kinase (PI3K), decreased EC- and EGC-induced glucose uptake activity in the cells. Cg and EGCg decreased phosphorylation of PKCλ/ζ in the presence of insulin without affecting insulin-induced phosphorylation of IR, and Akt. Therefore, EC and EGC promote the translocation of GLUT4 through activation of PI3K, and Cg and EGCg inhibit insulin-induced translocation of GLUT4 by the insulin signaling pathway in 3T3-L1 cells.     

Variable sampling inspection plans with screening for assuring average outgoing surplus quality loss limit indexed by Taguchi’s loss

Taguchi has proposed a variable-quality evaluation called “Taguchi’s quality loss” instead of the attribute quality evaluation such as the proportion of nonconforming items. Arizono et al. have proposed a single acceptance sampling plan based on operating characteristics from the viewpoint of assuring Taguchi’s quality loss. This sampling plan is designed to guarantee the constraints of the prescribed acceptance probabilities for respective lots with the allowable quality loss limit and the unallowable quality loss limit. However, in the acceptance sampling plan based on operating characteristics, the corrective action for rejected lot is not prescribed. On the other hand, the sampling inspection plan with screening is well known as the sampling scheme with the corrective action for rejected lots. Then, there is the attribute sampling inspection scheme with screening in order to guarantee the expectation of the proportion of nonconforming items in the shipping lot. However, the variable sampling inspection scheme with screening has not yet been prescribed. Then, in this article, we propose a variable sampling scheme with screening procedure for the purpose of assuring the upper limit of the maximum expected surplus loss indexed by Taguchi’s loss.     

Interpretation of actinide transmutation in thermal and fast reactors

The commonly used transmutation rate of minor actinides in nuclear reactors is decomposed into four components, overall fission rate, Pu production rate, MA production rate, and element production rate. The physical meanings of these factors are described. The transmutation rates of minor actinides in two types of highly-moderated PWRs, a MOX fueled Na cooled fast reactor, and a metal fueled Pb cooled fast reactor are interpreted using the four components. The metal fueled Pb cooled fast reactor can incinerate minor actinides most (79kg/GWth/year), and this amount is about 4 times larger than the thermal reactors. The thermal reactors have large relative overall fission rates for ²⁴¹Am and have a potential for the incineration of ²⁴¹Am.     

Recovery of minor actinides from spent molten salt waste and decontamination of molten salt waste

Recovery of minor actinides from spent molten salt is one of the important issues. Decontamination of spent molten salt waste is also the problem to be solved for establishment of pyrochemical reprocessing. The decontamination method of spent molten salt waste with recovery of minor actinides has been proposed. Our proposed process is based on the hydrometallurgical process. This process consists of the following processes. First, the spent molten salt waste is dissolved in aqueous solution. Next, the minor actinides are recovered by chromatographic techniques using the pyridine resin in the methanolic hydrochloric acid solution. In the last process, the spent molten salt waste is decontaminated by the cation-exchange chromatography. In the present paper, the adsorption behavior of minor actinides, rare earth elements, alkaline earth elements, and alkali metal elements on pyridine resin is reported. The demonstration experiment of the recovery of the minor actinides from simulant spent molten salt waste is also reported.     

Double‐metal complexation of heterogels containing cyanobacterial polysaccharides

Cryogenic‐transmission electron microscopy of metal complexes with cyanobacterial polysaccharides, sacran, extracted from Aphanothece sacrum biomaterials reveals that Nd³⁺ complexes form networks composed of thick strings with a thickness ranging 10–20 nm while Fe²⁺ ones make dense entanglement of very thin strings. When Fe²⁺ and Nd³⁺ double complexation occurs, dense nanonetworks composed of thick strings with a thickness around 10 nm are formed. Next we prepared heterogels by crosslinking poly(vinyl alcohol) chains in the presence of sacran and investigated the effects of double complexation on metal sorption. The amount of Nd³⁺ sorbed into the heterogels in the 1 : 1 miscible solution of Fe²⁺ and Nd³⁺ is higher than that in the solution containing only Nd^3+, suggesting that Fe²⁺ assists the Nd³⁺ sorption. In addition, it is found that the amount of sorbed Nd³⁺ is much higher than that of sorbed Fe²⁺ even in the acidic condition of pH 2. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Evaluation of genetic markers for identifying isolates of the species of the genus Fusarium

BACKGROUND: Members of the genus Fusarium are well known as one of the most important plant pathogens causing food spoilage and loss worldwide. Moreover, they are associated with human and animal diseases through contaminated foods because they produce mycotoxins. To control fungal hazards of plants, animals and humans, there is a need for a rapid, easy and accurate identification system of Fusarium isolates with molecular methods. RESULTS: To specify genes appropriate for identifying isolates of various Fusarium species, we sequenced the 18S rRNA gene (rDNA), internal transcribed spacer region 1, 5.8S rDNA, 28S rDNA, β‐tubulin gene (β‐tub), and aminoadipate reductase gene (lys2), and subsequently calculated the nucleotide sequence homology with pair‐wise comparison of all tested strains and inferred the ratio of the nucleotide substitution rates of each gene. Inter‐species nucleotide sequence homology of β‐tub and lys2 ranged from 83.5 to 99.4% and 56.5 to 99.0%, respectively. The result indicated that sequence homologies of these genes against reference sequences in a database have a high possibility of identifying unknown Fusarium isolates when it is more than 99.0%, because these genes had no inter‐species pair‐wise combinations that had 100% homologies. Other markers often showed 100% homology in inter‐species pair‐wise combinations. The nucleotide substitution rate of lys2 was the highest among the six genes. CONCLUSION: The lys2 is the most appropriate genetic marker with high resolution for identifying isolates of the genus Fusarium among the six genes we examined in this study. Copyright © 2011 Society of Chemical Industry