Inhibition of G1 cyclin expression in normal rat kidney cells by inostamycin, a phosphatidylinositol synthesis inhibitor

We previously reported that inostamycin, an inhibitor of CDP-DG: inositol transferase, inhibited cell proliferation in normal rat kidney (NRK) cells by blocking cell cycle progression at the G1 phase. In the present paper, we report the effect of inostamycin on the serum-induced activation of Ser/Thr protein kinases that are involved in G1 progression. In quiescent NRK cells mitogen-activated protein kinase (MAP kinase) and casein kinase II were activated within 15 min after serum addition. Neither activation was affected by the treatment with inostamycin. However, in the inostamycin-treated cell, cyclin-dependent kinase 2 (CDK2) failed to be activated after serum stimulation. Since serum-induced expression of cyclin E was also suppressed by inostamycin, this inhibitor would appear to block CDK2 activation by inhibiting cyclin E expression. Furthermore, inostamycin also inhibited cyclin D1 expression induced by serum; and consequently, hyperphosphorylation of retinoblastoma protein (pRB) by RB-kinases such as CDK4 and CDK2 was abolished, which would result in elimination of functional inactivation of pRB. Thus, early G1 arrest in NRK cells by inostamycin is due to the inhibition of cyclin D1 and E expressions.     

Characterization of microspherical semi-transparent solar cells and modules

Microspherical solar cells and modules have been fabricated. The spherical nature of these semi-transparent devices allows the microspherical cells to harvest both directly incident and diffuse components of sunlight thereby improving the solar energy conversion efficiency. Indoor and outdoor characterizations of these three dimensional semi-transparent cells and modules are carried out using a Lambertian reflector in order to assess the maximum efficiency of the devices. In the absence of the reflector the cell efficiency is 13.5% under standard illumination (100 mW cm⁻², A.M. 1.5, 25 °C). However, this is significantly enhanced in the presence of the reflector. Microspherical modules with the reflector are directly compared to similar semi-transparent modules comprised of traditional planar devices, in outdoor tests at low light intensity (2.5–25 mW cm⁻²) to further demonstrate the benefits of the design particularly at low angle of incident radiation.     

Fabrication of blue-light emission fused-silica substrates by using Si-ion implantation and high-temperature annealing

We fabricated fused-silica substrates which emit blue light by using Si-ion implantation and high-temperature annealing. Photoluminescence peak wavelengths are around 400 nm, and the peak intensities can be remarkable after annealing above 1150 °C.     

Novel Constitutive Equation for Predicting Dynamic Recrystallization During Hot Working Considering the Efficiency of Power Dissipation

The efficiency of power dissipation (η) in a dynamic material model has been conventionally used for qualitative predictions to estimate the hot working conditions at which dynamic recrystallization (DRX) is dominant. However, predicting the quantitative value of the DRX fraction (X_DRX) from η remains a challenge. In this paper, a constitutive equation is proposed to quantitatively predict X_DRX using η. The proposed equation for describing X_DRX is derived from the reaction rate equation using the assumption that the DRX rate depends on η. The proposed equation is verified via hot compression tests of equiaxed Ti–6Al–4V ELI alloys (Ti-64) in the (α + β) region. The predicted and experimental X_DRX values are found to be generally consistent with one another, exhibiting an average absolute error of 0.05. Furthermore, the proposed equation provides the same level of prediction accuracy as the conventional Johnson–Mehl–Avrami–Kolmogorov (JMAK) equation. Therefore, the proposed equation can be used to quantitatively predict X_DRX following hot compression tests of equiaxed Ti-64. Moreover, compared with the JMAK equation, the proposed equation is expressed in fewer parameters and constant terms. It is, thus, expected to facilitate the quantitative prediction of X_DRX.

     

Extraction and implementation of muscle synergies in neuro-mechanical control of upper limb movement

This work faces the redundancy problem, a central concern in robotics, in a particular force-producing task by using muscle synergies to simplify the control. We extracted muscle synergies from human electromyograph signals and interpreted the physical meaning of the identified muscle synergies. Based on the human analysis results, we hypothesized a novel control framework that can explain the mechanism of the human motor control. The framework was tested in controlling a pneumatic-driven robotic arm to perform a reaching task. This control method, which uses only two synergies as manipulated variables for driving antagonistic pneumatic artificial muscles to generate desired movements, would be useful to deal with the redundancy problem; thus, suggesting a simple but efficient control for human-like robots to work safely and compliantly with humans.     

Lysozyme requires fluctuation of the active site for the manifestation of activity

Mutations around His15 which lie far away from the active site,stimulated glycol chitin activity of lysozyme at physiologicaltemperature. Del-Argl4Hisl5 lysozyme, a mutant lysozyme whoseArgl4 and Hisl5 were deleted together, and has the highest activityamong these mutant lysozymes, had a similar binding abilityto a trimer of N-acetyl-glucosamine, a substrate analogue, relativeto native lysozyme. This suggests that the increased activitywas due to an increased k_cat in the catalysis reaction. TheH-D exchange rate of the N-1 proton in the Trp63 which is locatedin the active site cleft, was enhanced in the Del-Argl4Hisl5lysozyme, while 2-D proton NMR analysis revealed no conformationalchange around Trp63. We conclude that some sort of fluctuationat the active site might be required for the manifestation ofactivity. This theory is supported by the finding that the Del-Argl4Hisl5lysozyme showed a shift in temperature dependency of activityto lower temperatures compared with that of native lysozyme.     

Effective renaturation of reduced lysozyme by gentle removal of urea

To increase the folding yield of concentrated reduced lysozyme,we developed a renaturation method by means of dialysis fromconcentrated urea with redox agents. After lysozyme was incubatedin the reducing buffer (8 M urea solution) with oxidized glutathione,renaturation of reduced lysozyme was started by dialysis againstthe dialyzing buffer containing 8 M urea with redox agents.The urea concentration of the dialyzing bottle was graduallydiluted with dialyzing buffer without urea at a flow rate of0.1 ml/min by high pressure pump. Using this systematic dialysis,a concentration as high as 5 mg/ml of reduced lysozyme couldbe renaturated in 80% yield, while the folding yield was <5%even at a concentration of 1 mg/ml using a conventional rapiddilution method [Goldberg et al. (1991) Biochemistry, 30, 2790–2797].Therefore, it was concluded that gentle removal of urea fromdenatured proteins, dissolved in concentrated urea solution,by means of dialysis should be useful to renature denaturedproteins effectively.     

A control method with pheromone information for a transport system

Since the control methods of a transport system between processing machines are specialized for each layout of the system, it is difficult to design prompt schedules and control logic for new complicated systems, especially in cases of machine faults or restructuring the system to modify the layout. In this article, we describe a multiagent transport control system which utilizes pheromone information. Each element of the system acts as an agent and estimates the appropriate path and time to drive out the products using information obtained by communication with other elements as well as pheromone information deposited on the tracks of the products.     

Platform design for large-scale artificial market simulation and preliminary evaluation on the K computer

Artificial market simulations have the potential to be a strong tool for studying rapid and large market fluctuations and designing financial regulations. High-frequency traders, that exchange multiple assets simultaneously within a millisecond, are said to be a cause of rapid and large market fluctuations. For such a large-scale problem, this paper proposes a software or computing platform for large-scale and high-frequency artificial market simulations (Plham: /pl\(\Lambda\)m). The computing platform, Plham, enables modeling financial markets composed of various brands of assets and a large number of agents trading on a short timescale. The design feature of Plham is the separation of artificial market models (simulation models) from their execution (execution models). This allows users to define their simulation models without parallel computing expertise and to choose one of the execution models they need. This computing platform provides a prototype execution model for parallel simulations, which exploits the variety in trading frequency among traders, that is, the fact that some traders do not require up-to-date information of markets changing in millisecond order. We evaluated a prototype implementation on the K computer using up to 256 computing nodes.