Flexible System LSI for Embedded Systems and Its Optimization Techniques

In this paper, we propose a chip architecture and design techniques to simultaneously reduce both the chip cost and power consumption of system-on-a-chip (SOCs). The chip cost of SOCs consists of the design cost, the mask cost, the fabrication cost, the package cost, and the test cost. In case that the production volume of one design is large, the fabrication cost becomes relatively larger than other costs. The minimization of the fabrication cost by shrinking the chip area has been the main problem to reduce the chip cost. SOCs are not always mass-produced and their design and the mask costs are dominant. We need new design criteria and a new design methodology for SOCs whose production volume is small. Our major contribution is a proposal of a design methodology based on new criteria suitable for SOC design. In our methodology, system designers use a pre-fabricated chip, called Flexible System LSI (FlexSys) chip, which consists of a processor, memories, and other cores specific to an application domain. At the fabrication phase, the power supply for unused parts of the FlexSys chip is cut off using a few additional masks which are designed for a specific application. This leads the reduction of wasteful power consumed by circuits which do not essentially contribute to the computation of the application. Since the basic die of the FlexSys is fabricated as a general purpose product, we can reduce the cost of the dies drastically. Experimental results show that about 30% power reduction can be achieved without performance loss by reducing the wasteful power consumption.     

Hydrogenolysis of sugar beet fiber by supported metal catalyst

Sugar beet fiber is an agricultural by-product in the sugar manufacturing and an available biomass source with a rich hemicellulose component. So far, there has been no report on the catalytic conversion of the beet fiber for the synthesis of chemicals. In this work, the hydrogenolysis of the beet fiber was studied by using supported metal catalysts under pressurized hydrogen conditions. Activated carbon supported Ru was found to show the highest catalytic activity to give arabitol as a major product in the hydrogenolysis of hemicellulose part of this material. The reuse ability of the catalyst was also investigated.     

Influence of fetal calf serum on differentiation of mesenchymal stem cells to chondrocytes during expansion

Mesenchymal stem cells (MSCs) should be expanded in vitro while maintaining their multilineage potential before differentiation to one mesenchymal lineage for application to regeneration therapy. The effect of fetal calf serum (FCS) on undesirable differentiation during subcultivations for the expansion was investigated. The expression level of the aggrecan gene, which is a marker of chondrogenic differentiation, gradually and markedly increased during the subcultivations of MSCs with the addition of 10% FCS and without additional cytokines. The percentage of cells positive for CD90 and CD166, which are markers of MSCs, decreased, and the percentage of large polygonal cells and the average cell adhesion area increased during the expansion. There was a marked difference in the increase in the aggrecan expression level between the two expansion cultures employing different FCS lots, although their proliferation rates were almost the same. The decrease in FCS concentration resulted in a higher percentage of CD90(+)CD166(+) cells, a lower percentage of large polygonal cells, and a lower level of aggrecan expression. Consequently, FCS components could stimulate MSC differentiation to chondrocytes and a lower concentration could decrease this differentiation.     

Wettability of liquid caesium iodine and boron oxide on yttria-stabilized zirconia

During the Fukushima Daiichi Nuclear Power Plant accident occurred in 2011, volatile fission products (FPs) such as Cs and I had released and caused environmental contamination and public exposure, respectively. However, the release mechanism of these FPs from fuels under the accident is still not completely understood. In recent years, we have focused on the wettability of liquid FPs against solid fuels, because the interface between the fuel surface and the FPs becomes the migration pathway, which might have large influences on the release behaviour of the FPs. Here, we studied the wettability of liquid CsI and B₂O₃ on yttria-stabilized zirconia (YSZ) solid surface by the sessile drop test, where YSZ is a simulated material of the fuel. It was revealed that liquid CsI exhibited extremely high wettability against the YSZ surface with the contact angle of nearly zero. This high wettability may act to suppress the FPs release. Furthermore, it was confirmed that the crystal orientation and surface roughness of the YSZ solids have large influences on the wettability of liquid B₂O₃. The present results contribute for deep understanding of the release behaviour of the volatile FPs from fuels.     

Double-integrator control for precision positioning in the presence of friction

In order to achieve good performance in precision positioning systems where friction is present, a straightforward approach is using single-integrator controllers to suppress the effect of friction. In this paper, double-integrator (DI) control, in which two integrators are involved, is proposed to enhance controller gain at lower frequencies. A new integral anti-windup scheme is developed for the DI control and is shown to be effective. Performance of a DI controller is compared with that of a proportional-integral-derivative controller (I-PD) and a pole-placement-with-integration controller (PPI) by experiment on a slide system driven by a dc motor. In the system, the dc motor has brushes that give rise to friction, and all other frictional contacts are removed by frictionless aerostatic support. Because of the unmodeled high frequency dynamics caused by aerostatic dynamics, closed-loop bandwidth with the I-PD controller is limited at a lower value than in the cases with the DI and PPI controllers. With the three controllers having parameters for similar closed-loop bandwidths, the DI controller gives uniform closed-loop responses to step inputs of different heights, while for the other two controllers the responses are obviously dependent on the height of the step inputs.     

Children of depressed mothers: Maternal strain and symptom predictors of dysfunction.

Because of both methodological and theoretical limitations, previous studies of offspring of parents with affective disorders have rarely tested psychosocial models of depressive vulnerability. The current research is part of a longitudinal investigation of psychosocial risk for disorder in 8- to 16-year-old children of unipolar, bipolar, medically ill, and normal mothers. High rates of psychopathology, including depression, were found in children in the high-risk groups. The current study evaluated the separate contributions of maternal depressive history, current self-reported depressive symptoms (Beck Depression Inventory scores), and chronic strains to observe relations between these ordinarily confounded variables and children's psychiatric diagnoses and current functioning. Hierarchical regression analyses indicated that chronic strain added significantly to the prediction of several outcomes and that current depressive symptoms were more predictive of children's scores than was maternal history of affective disorder. Both chronic strains and current Beck Depression Inventory scores are viewed as concomitants of affective disorder but are not specific to it. Therefore studies of the risk to children conferred by parental disorder cannot assume that diagnostic status as such is a single risk factor and must attend to the effects of ongoing stressors and nonspecific symptoms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An integrated approach to source term uncertainty and sensitivity analyses for nuclear reactor severe accidents

Large-scale computer programs simulate severe accident phenomena and often have a moderate-to-large number of models and input variables. Analytical solutions to uncertainty distributions of interested source terms are impractical, and influential inputs on outputs are hard to discover. Runs of such integral codes for complex severe accidents are generally time-consuming and hence computationally expensive. This article presents an integrated approach to uncertainty and sensitivity analyses for nuclear reactor severe accident source terms, with an example which simulates an accident sequence similar to that occurred at Unit 2 of the Fukushima Daiichi Nuclear Power Plant using an integral code, MELCOR. Monte-Carlo-based uncertainty analysis has been elaborated to investigate the released fractions of representative radionuclides, Cs and CsI. In order to estimate the sensitivity of inputs, which have a substantial influence on the core melt progression and the transportation process of radionuclides, a variance decomposition method is applied. Stochastic process, specifically a Dirichlet process, is applied to construct a surrogate model in sensitivity analysis as a substitute of the code. The surrogate model is cross-validated by comparing with corresponding results of MELCOR. The analysis with the simpler model avoids laborious computational cost/load, so that the importance measures for input factors are obtained successfully.     

Parallel Post‐Polyketide Synthase Modification Mechanism Involved in FD‐891 Biosynthesis in Streptomyces graminofaciens A‐8890

To isolate a key polyketide biosynthetic intermediate for the 16‐membered macrolide FD‐891 ( 1 ), we inactivated two biosynthetic genes coding for post‐polyketide synthase (PKS) modification enzymes: a methyltransferase (GfsG) and a cytochrome P450 (GfsF). Consequently, FD‐892 ( 2 ), which lacks the epoxide moiety at C8–C9, the hydroxy group at C10, and the O‐methyl group at O‐25 of FD‐891, was isolated from the gfsF/gfsG double‐knockout mutant. In addition, 25‐O‐methyl‐FD‐892 ( 3 ) and 25‐O‐demethyl‐FD‐891 ( 4 ) were isolated from the gfsF and gfsG mutants, respectively. We also confirmed that GfsG efficiently catalyzes the methylation of 2 and 4 in vitro. Further, GfsF catalyzed the epoxidation of the double bond at C8‐C9 of 2 and 3 and subsequent hydroxylation at C10, to afford 4 and 1 , respectively. These results suggest that a parallel post‐PKS modification mechanism is involved in FD‐891 biosynthesis.     

Evaluation of Pulmonary Toxicity of Zinc Oxide Nanoparticles Following Inhalation and Intratracheal Instillation

We conducted inhalation and intratracheal instillation studies of zinc oxide (ZnO) nanoparticles in order to examine their pulmonary toxicity. F344 rats were received intratracheal instillation at 0.2 or 1 mg of ZnO nanoparticles with a primary diameter of 35 nm that were well-dispersed in distilled water. Cell analysis and chemokines in bronchoalveolar lavage fluid (BALF) were analyzed at three days, one week, one month, three months, and six months after the instillation. As the inhalation study, rats were exposed to a concentration of inhaled ZnO nanoparticles (2 and 10 mg/m³) for four weeks (6 h/day, 5 days/week). The same endpoints as in the intratracheal instillation study were analyzed at three days, one month, and three months after the end of the exposure. In the intratracheal instillation study, both the 0.2 and the 1.0 mg ZnO groups had a transient increase in the total cell and neutrophil count in the BALF and in the expression of cytokine-induced neutrophil chemoattractant (CINC)-1, CINC-2, chemokine for neutrophil, and heme oxygenase-1 (HO-1), an oxidative stress marker, in the BALF. In the inhalation study, transient increases in total cell and neutrophil count, CINC-1,-2 and HO-1 in the BALF were observed in the high concentration groups. Neither of the studies of ZnO nanoparticles showed persistent inflammation in the rat lung, suggesting that well-dispersed ZnO nanoparticles have low toxicity.