Simulating Adaptive Human Bipedal Locomotion Based on Phase Resetting Using Foot-Contact Information

Humans generate bipedal walking by cooperatively manipulating their complicated and redundant musculoskeletal systems to produce adaptive behaviors in diverse environments. To elucidate the mechanisms that generate adaptive human bipedal locomotion, we conduct numerical simulations based on a musculoskeletal model and a locomotor controller constructed from anatomical and physiological findings. In particular, we focus on the adaptive mechanism using phase resetting based on the foot-contact information that modulates the walking behavior. For that purpose, we first reconstruct walking behavior from the measured kinematic data. Next, we examine the roles of phase resetting on the generation of stable locomotion by disturbing the walking model. Our results indicate that phase resetting increases the robustness of the walking behavior against perturbations, suggesting that this mechanism contributes to the generation of adaptive human bipedal locomotion

Suzaku Observations of M82 X-1 : Detection of a Curved Hard X-ray Spectrum

A report is presented on Suzaku observations of the ultra-luminous X-ray source X-1 in the starburst galaxy M82, made three time in 2005 October for an exposure of ~ 30 ks each. The XIS signals from a region of radius 3 around the nucleus defined a 2-10 keV flux of 2.1 x 10^-11 erg s-1 cm-2 attributable to point sources. The 3.2-10 keV spectrum was slightly more convex than a power-law with a photon index of 1.7. In all observations, the HXD also detected signals from M82 up to ~ 20 keV, at a 12-20 keV flux of 4.4 x 10^-12 erg s-1 cm-2 . The HXD spectrum was steeper than that of the XIS. The XIS and HXD spectra can be jointly reproduced by a cutoff power-law model, or similar curved models. Of the detected wide-band signals, 1/3 to 2/3 are attributable to X-1, while the remainder to other discrete sources in M82. Regardless of the modeling of these contaminants, the spectrum attributable to X-1 is more curved than a power-law, with a bolometric luminosity of (1.5 -3) x 10 ^40 erg s-1. These results are interpreted as Comptonized emission from a black hole of 100-200 solar masses, radiating roughly at the Eddington luminosity.Comment: 19 pages, 9 figures, accepted in Publications of the Astronomical Society of Japa

Synthesis of Pyrrolo [2,1-b] thiazolines Using N-(Trimethylsilylmethyl)-2- methylthiothiazolinium Trifluoromethanesulfonate

N-(Trimethylsilylmethyl)-2-methylthiothiazolinium trifluoromethanesulfonate(4), readily prepard from 2-methylthiothiazoline (2) and trimethylsilylmethyl trifluoromethenesulfonate (1), reacted with activated alkenes (5) and alkynes (6) in the presence of cesium fluoride in acetonitrile to give the corresponding 4, 5-dihydropyrrolo [2, 1-b] thiazoline and pyrrolo [2, 1-b] thiazoline derivatives. The 1, 3-dipolar cycloaddition reaction is one of the most important reaction to construct five-membered heterocycles. We have reported that tailor-made azomethine and thiocarbonyl ylids can be generated by the 1, 3-elimionation reaction of trimethylsilylmethyl- substituted ketene N,S- or S,S- acetals promoted by fluoride ion and react with dipolarophiles to give five-membered heterocycles. As an unpublished result, we have recognized that the reactuion of 3-trimethylsilylmethylamino-3-methylthio-2- cyanoacrylonitrile with dipolarophiles in the presence of a fluoride ion gives five-membered heterocycles but the reaction of 3-trimethylsilylmethylamino-2-cyanoacrylonitrile with dipolarophiles gives no cycloadducts. These facts have shown that the elimination of a methylthio group following cleavage of carbon-silicon bond is a useful tool for the generation of 1,3-dipolar. Here we descrive the reaction of N-(trimethylsilylmethyl)-2- methythiothiazolinium trifluoromethanesulfonate, which has a Me3SiCH2 -N=C-SMe system, with dipolarophiles gives 4,5-dihydropyrrolo [2,1 - b] thiazoline derivatives. Trimethysilylmethyl trifluoromethanesulfonate (1) is an interesting compound to the preparation of silicon-containing sulfonium, nitrogen and other ylids. Starting material 1 was prepared according to the literature. A solution of 2-methylthiothiazoline (2) in dichloromethane was treated with 1 and stirred at room temperature for over night. After the solvent was removed N- (trimethylsilymethyl)-2-methylthiothiazolinium trifluoromethanesulfonate (4) was afforded. The crude salt 4 was used in the next step without purification. A solution of 4, thus obtained, and dimethyl fumarate(6b) in the prsence of cesium fluoride in acetonitrile was stirred at room temperature for 24h. The usual work-up after treatment with aqueous ammonium chloride and separation by preparative t.l.c. gave dimethyl 4,5-dihydropyrrolo [2, 1-b] thiazoline -5, 6-dicarboxylate(7b), formal [3+2] cycloaddition product, in 53% yield. The cycloadditon behavior of an unsymmetrically substituted dipolarophile was studied to determine the regioselectivity of the reaction. The reaction of 4 and methyl acrylate (6a) under the similar conditions gave methyl 4,5-dihydop yrrolo [2,1-b] thiazoline-6-carboxylate (7a) in 57% yield, exclusively. When methyl cinnamate (6d) was used as a dipolarophile, cycloadduct 7d was obtained as a single pro duct. The representative results are listed in Table 1. N-(Trimethylsilylmethyl)-2- methylthiobenzothia-zolium trifluoromethenesulfonate (5) was also prepared and reacted with activated alkenes (6a-6d) to give the corresponding [3+2] cycloadducts (8a-8d) in a manner similar to that described for 7a. The reaction also shows complete regiospecificity in the cycloaddition with unsymmetrically substituted olefins. However the reactions of 4 and 5 with N-methylmaleimide was unsuccessful under the present reaction conditions. Salt 4 and 5 reacted with alkynes (9a and 9b) under the similar conditions to give [3+2] cycloaiddition products, pyrrolo [2, 1-b] thiazoline derivatives(10a and 10b) and pyrrolo [2, 1-b] benzothiazole derivatives (11a and 11b). (see Table 2) This work demonstrates a mild and simple procedure for the preparation of pyrrolo [2, 1-b] thiazoline and pyrrolo [2, 1-b] benzothiazole derivatives

Current status of MHI’s CO2 recovery technology and optimization of CO2 recovery plant with a PC fired power plant

AbstractIt is the opinion of the authors that CO2 Capture and Storage (CCS) technology can significantly contribute as an effective countermeasure against climate change, allowing us to continue the utilization of fossil fuels for primary energy production. However for this technology to be widely deployed on a commercial basis there are three key issues that need to be addressed; (1) Reduction in energy consumption, (2) Efficient integration with other environmental control equipment of a PC power plant and (3) Reduction in the decrease of net electrical output.MHI has delivered multiple commercial CO2 recovery plants in the chemical and fertilizer industries, which recover CO2 from natural gas fired flue gas, with four commercial plants in operation and another four under construction, all utilizing the proprietary KM-CDR process.In order to gain experience with CO2 recovery from a coal fired flue gas stream, Mitsubishi Heavy Industries (MHI), together with a subsidy from RITE and cooperation from J-POWER, constructed a 10 metric ton per day (T/D) CO2 recovery demonstration plant at the 2×500 MW Matsushima power station in southern Japan. This demonstration plant has subsequently achieved more than 4,000 hours of successful test operation during 2006–2007 with a further 1,000 hours during 2008, and testing continues today. The demonstration testing confirmed that the KM-CDR process is applicable to coal fired flue gas streams. Future research priorities include the improved integration of the CO2 recovery process with the flue gas pre-treatment components and the additional optimization of removal and separation methods for coal based impurities accumulating in the absorbent.An issue of concern for power plant operators is the reduction of the net electrical output due to the demands of CO2 recovery process. MHI has made significant improvements in this area and in the efficiency of absorbents. However, it is necessary to further reduce the adverse impact on the net electrical output of the power plant via astute integration of the energy transferred between the power plant and the Post Combustion CO2 Capture (PCC) plant. MHI is investigating the following concepts; (1) Utilizing the waste heat of the PCC plant for the power plant, (2) Utilizing heat recovery from the flue gas for the CO2 recovery process and (3) Utilizing the compression heat of the CO2 compressor for the CO2 recovery process

Fractal mechanism of basin of attraction in passive dynamic walking

Passive dynamic walking is a model that walks down a shallow slope without any control or input. This model has been widely used to investigate how humans walk with low energy consumption and provides design principles for energy-efficient biped robots. However, the basin of attraction is very small and thin and has a fractal-like complicated shape, which makes producing stable walking difficult. In our previous study, we used the simplest walking model and investigated the fractal-like basin of attraction based on dynamical systems theory by focusing on the hybrid dynamics of the model composed of the continuous dynamics with saddle hyperbolicity and the discontinuous dynamics caused by the impact upon foot contact. We clarified that the fractal-like basin of attraction is generated through iterative stretching and bending deformations of the domain of the Poincaré map by sequential inverse images. However, whether the fractal-like basin of attraction is actually fractal, i.e., whether infinitely many self-similar patterns are embedded in the basin of attraction, is dependent on the slope angle, and the mechanism remains unclear. In the present study, we improved our previous analysis in order to clarify this mechanism. In particular, we newly focused on the range of the Poincaré map and specified the regions that are stretched and bent by the sequential inverse images of the Poincaré map. Through the analysis of the specified regions, we clarified the conditions and mechanism required for the basin of attraction to be fractal

Preoperative oral administration of pentoxifylline ameliorates respiratory index after cardiopulmonary bypass through decreased production of IL-6

Activation of inflammatory response during cardiopulmonary bypass (CPB) may lead to considerable post-operative mortality. Recently, pentoxifylline (PTX), a methylxanthine derivative, has been reported to be effective in inhibiting proinflammatory cytokine production. This study aimed to determine whether or not PTX prevented CPB-induced systemic inflammatory response syndrome (SIRS) in patients undergoing cardiovascular surgery. Thirty adult patients were randomly separated into 2 experimental groups and 1 control group of 10 patients each. The experimental group received peroral PTX administration (Group 1: 600 mg/day, Group 2: 900 mg/day), while the control group did not. In Group 1 and Group 2, PTX administration was started on preoperative day 5 and continued for 5 days. Serum levels of PTX and IL-6 were measured just before and at 4 h after CPB using HPLC and ELISA, respectively. Respiratory index (RI) before and at 4 h after CPB was calculated, and serum levels of C-reactive protein (CRP) and fibrinogen on postoperative day 1 were also determined. There were no significant differences in age, body weight, sex, surgical procedures, CPB time, haemodynamics or risk factors among the 3 groups. Serum IL-6 level and RI index after CPB in Group 2 were significantly decreased compared with those in Group 1 and the control group. These results, therefore, suggested that preoperative daily administration of 900 mg/day PTX contributed to the attenuation of CPB-induced SIRS and had a beneficial effect on the postoperative course after cardiovascular surgery.</p