Neutrophil Elastase Deficiency Ameliorates Myocardial Injury Post Myocardial Infarction in Mice

Neutrophils are recruited into the heart at an early stage following a myocardial infarction (MI). These secrete several proteases, one of them being neutrophil elastase (NE), which promotes inflammatory responses in several disease models. It has been shown that there is an increase in NE activity in patients with MI; however, the role of NE in MI remains unclear. Therefore, the present study aimed to investigate the role of NE in the pathogenesis of MI in mice. NE expression peaked on day 1 in the infarcted hearts. In addition, NE deficiency improved survival and cardiac function post-MI, limiting fibrosis in the noninfarcted myocardium. Sivelestat, an NE inhibitor, also improved survival and cardiac function post-MI. Flow cytometric analysis showed that the numbers of heart-infiltrating neutrophils and inflammatory macrophages (CD11b⁺F4/80⁺CD206^low cells) were significantly lower in NE-deficient mice than in wild-type (WT) mice. At the border zone between intact and necrotic areas, the number of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive apoptotic cells was lower in NE-deficient mice than in WT mice. Western blot analyses revealed that the expression levels of insulin receptor substrate 1 and phosphorylation of Akt were significantly upregulated in NE-knockout mouse hearts, indicating that NE deficiency might improve cardiac survival by upregulating insulin/Akt signaling post-MI. Thus, NE may enhance myocardial injury by inducing an excessive inflammatory response and suppressing Akt signaling in cardiomyocytes. Inhibition of NE might serve as a novel therapeutic target in the treatment of MI.     

Incident energy dependence of the scattering dynamics of water molecules on silicon and graphite surfaces: the effect on tangential momentum accommodation

The scattering dynamics of water molecules on solid surfaces was investigated using the molecular beam technique. In contrast to the experiments previously reported in the literature, the range of incident energy was chosen to cover the typical kinetic energies of gas molecules in equilibrium at room temperature (35–130 meV). Even in such a narrow energy range, the angular distribution of scattered molecules is heavily affected by the incident energy, exhibiting both a nearly cosine distribution and a lobular distribution, which has a clear peak close to the specular direction. Interestingly, the tangential momentum accommodation coefficients (TMACs) estimated from the scattering experiments show opposite energy dependences on graphite (0001) and silicon (100) surfaces. As the incident energy increases, the TMAC decreases on the graphite surface, whereas it increases on the silicon surface. These trends can be attributed to the relatively large adsorption energy of water molecules on these surfaces and the atomic-scale surface corrugation, although a rigorous understanding requires further analysis by molecular dynamics simulations. Our findings suggest the need for an elaborate slip-flow model that takes account of the incident energy effect to accurately analyze water vapor flow in micro/nanostructures, which is ubiquitous in nature and engineering applications.     

High-speed stability of a rigid rotor supported by aerostatic journal bearings with compound restrictors

Demands for higher rotational speed and accuracy for effective manufacture of small holes on printed circuit boards and very small precise parts have been increasing remarkably. Aerostatic journal bearings with compound restrictors have greater stiffness than those with conventional inherently compensated restrictors and are one of the most effective candidates to satisfy these demands. In this work, the instability of a rigid rotor supported by aerostatic journal bearings with compound restrictors was investigated numerically and experimentally. It was found that this type of aerostatic bearings showed a much higher threshold speed for instability compared with bearings with inherently compensated restrictors.     

Nonlinear analysis on dynamic behavior of buoyancy-induced flame oscillation under swirling flow

From the viewpoint of nonlinear dynamics, the dynamic behavior of buoyancy-induced flame oscillation has been experimentally investigated under a swirling flow produced by rotating a cylindrical burner tube. As the rotational Reynolds number increases, the dynamic behavior undergoes a significant transition from periodic oscillation to low-dimensional deterministic chaos, through quasi-periodic oscillation. This is clearly demonstrated by nonlinear time series analysis based on chaos theory. The motion of the vortical structure around the burner tube due to the centrifugal instability associated with a rotating Taylor–Couette flow plays an important role in the onset of low-dimensional deterministic chaos.     

Effect of reaction temperature on Fe–Al analcime formation

The effects of reaction period, temperature, and iron species on the zeolite framework type were studied in this work. Gismondine (GIS) is usually synthesized by hydrothermal method at 80°C from sodium metasilicate and aluminum nitrate as starting materials preferentially independent of the presence/absence of iron source. However, the present work revealed that pure analcime (ANA) could be formed at temperatures more than 120°C. A large polyhedral ANA crystal with a diameter of 180 μm was obtained even at a comparatively low temperature such as 150°C at a short reaction period of 1 week. The presence of iron source promoted the formation of pure ANA. Infrared spectroscopy, X-ray diffraction, and ICP-OES analysis suggested that the iron component added as a reactant was incorporated into the ANA framework through the isomorphous substitution for Al.     

Baggage Transportation and Navigation by a Wheeled Inverted Pendulum Mobile Robot

Our goal is to configure an automatic baggage-transportation system by an inverted pendulum robot and realize a navigation function in a real environment. The system consists of two cooperative subsystems: a balancing-and-traveling control subsystem and a navigation subsystem. Position errors of the inverted pendulum robot are often caused by a drift error in the gyro sensor and a change in the center of gravity by a loaded baggage when applying the linear state feedback control method for balancing and traveling. We have reduced the position errors for navigation by resetting the balance position occasionally while traveling with simple methods without an external observer or alternative sensors. In this paper, we state the method and show the experimental results of navigation in a real environment by the implemented robot system.     

Epidemic models and a self-repairing network with a simple lattice

We have proposed a self-repairing network where nodes are capable of repairing neighboring nodes by mutually copying. A critical point where faulty nodes can be eliminated has been investigated. This paper further studies the dynamics of eradicating faulty nodes by comparing the self-repairing network with mathematical epidemic models such as SIS models. It is shown that the self-repairing network, which is a probabilistic cellular automaton, can be regarded as an epidemic model in some restricted situations. This work was presented in part at the 12th International Symposium on Artificial Life and Robotics. Oita, Japan, January 25–27, 2007     

Effects of laser peening on the fatigue strength and defect tolerance of aluminum alloy

The effects of laser peening (LP) on the bending fatigue strength of the 7075‐T651 aluminum alloy were investigated. Accordingly, the defect tolerance of the aluminum alloy subjected to LP is discussed on the basis of fracture mechanics. The results indicate that a deeper compressive residual stress was induced by LP compared with the case of shot peening (SP). The fatigue strengths increased when both peening types were used. Semicircular slits with depths less than 0.4 and 0.1 mm were rendered harmless on the basis of the applications of LP and SP, respectively. The apparent threshold stress intensity factor range ΔK_th,ap increased by approximately five and two times owing to LP and SP, respectively. The increase of the ΔK_th,ap was caused by the compressive residual stress induced by the peening. The Kitagawa‐Takahashi diagram of the laser‐peened specimens shows that the defect tolerance of the aluminum alloy was improved by LP.