Helium gas permeability of montmorillonite/epoxy nanocomposites

Helium gas permeability of silicate clay (montmorillonite) particles/epoxy nanocomposites was examined. The incorporation of increasing amounts of montmorillonite particles reduced the helium gas permeability. Based on Fick’s law, gas permeation behavior of the nanocomposite was evaluated. With the increase of montmorillonite loading, gas diffusivity decreased, while gas solubility increased. Helium diffusion behavior is in agreement to the numerical results based on the Hatta–Taya–Eshelby theory. It has been revealed that dispersion of nanoscale platelets in polymer is effective in improving gas barrier property.     

Ion-velocity dependence of high-density electronic excitation effects in oxide superconductors

Thin films of EuBa₂Cu₃O_y oxide superconductor have been irradiated with high energy heavy ions (80 MeV I, 125 MeV Br, 1.1 GeV Mo and 3.5 GeV Xe) having same electronic stopping power, S_e, in order to investigate the ion-velocity dependence of the electronic excitation effects under the constant electronic energy deposition. Although S_e is constant, a strong reduction in the irradiation effect on lattice parameter with increasing ion-velocity is observed in the low ion-velocity region around E  1 MeV/nucleon, while the ion-velocity dependence is hardly observed in the high ion-velocity region of E > 10 MeV/nucleon. If the observed velocity-dependence is assumed to be due to the change in the fraction of S_e contributing to defect creation, the fraction in the low velocity region (E  0.6 MeV/nucleon) is estimated to be about two times larger than that in the high velocity region (E > 10 MeV/nucleon).     

Hydraulic Study of the Onset of Hypoxia in the Tone River Estuary

Field measurements were conducted to investigate the onset and growth of hypoxia in the Tone River Estuary. Vertical profiles of dissolved oxygen (DO), salinity, and temperature were measured along the deepest line of the estuary. Rates of oxygen consumption by water and sediment in a salt wedge were obtained using laboratory tests. The measurements showed that hypoxia frequently occurred in the front part of the salt wedge and expanded its area toward the river mouth during the summer when the river flow rate was small. The data also suggested that the onset of hypoxia was delayed by the estuarine circulation which supplied oxygen-rich seawater to the salt wedge. To simulate this phenomenon, a two-dimensional flow model in the vertical-longitudinal plane was constructed by transversely integrating the k–ε model equations. The results of model simulation for three months in the summer of 1997 closely matched the field data. The model simulation proved that DO degradation is highly correlated with the residence time of salt water in the estuary.     

ST-segment elevation in right precordial leads implies depressed right ventricular function after acute inferior myocardial infarction

BACKGROUND: The prognosis of acute inferior myocardial infarction is worse when it is complicated by right ventricular infarction. ST elevation in the right precordial leads is one of the reliable methods for detecting acute right ventricular infarction. The purpose of the study was to examine the relation between ST elevation in the right precordial electrocardiographic leads during acute inferior infarction and the severity of right ventricular systolic dysfunction. METHODS: This study analyzed the relation between ST elevation > or = 0.1 mV in V4R and the severity of right ventricular systolic dysfunction in 43 consecutive patients (men/women: 35/8; average age 62+/-9 years) with acute inferior myocardial infarction with a rapid-response Swan-Ganz catheter to measure the right ventricular ejection fraction (RVEF). RESULTS: RVEF was significantly lower in patients with ST elevation (n = 18) than in those without (n = 25) (33%+/-6% vs 40%+/-9%, p = 0.010). If the infarct-related lesion was located in the proximal right coronary artery, RVEF tended to be lower than if the lesion was located in the distal right coronary artery or the left circumflex coronary artery (33%+/-10% vs 37%+/-9% vs 42%+/-9%, p = 0.101). Logistic regression analysis demonstrated that ST elevation in V4R was the only independent predictor of depressed RVEF (odds ratio = 5.31, 95% confidence interval = 1.28 to 22.1, p = 0.022). CONCLUSION: ST elevation in lead V4R during acute inferior myocardial infarction predicts right ventricular systolic dysfunction.     

Deuterium trapping by irradiation damage in tungsten induced by different displacement processes

The deuterium trapping behaviors in tungsten damaged by light ions with lower energy (10 keV C⁺ and 3 keV He⁺) or a heavy ion with higher energy (2.8 MeV Fe²⁺) were compared by means of TDS to understand the effects of cascade collisions on deuterium retention in tungsten. By light ion irradiation, most of deuterium was trapped by vacancies, whose retention was almost saturated at the damage level of 0.2 dpa. For the heavy ion irradiation, the deuterium trapping by voids was found, indicating that cascade collisions by the heavy ion irradiation would create the voids in tungsten. Most of deuterium trapped by the voids was desorbed in higher temperature region compared to that trapped by vacancies. It was also found that deuterium could accumulate in the voids, resulting in the formation of blisters in tungsten.     

Second harmonic generation of pseudo mode-locked multi ten milliwatt picosecond Ti:sapphire laser

We report the single-pass second harmonic generation (SHG) of the picosecond Ti:sapphire laser with a periodically poled lithium niobate (PPLN) waveguide. We demonstrate a conversion efficiency of 37% for the 9-mW fundamental input power at 820 nm. This laser source can provide three types of pulsed modes such as picosecond, nanosecond, and contiuous wave, by adjusting the power of the pumping source. We compare the conversion efficiency in each mode, and clearly show that SHG efficiency depends on the pulsewidth, that is, the peak power of the laser source. As the temperature of the PPLN rises, the fundamental wavelength for phase-matching becomes longer. We indicate that the rate is about 0.06 nm/K.     

Design of experiments for stacking sequence optimizations with genetic algorithm using response surface approximation

This study describes a new method of experimental design to obtain a response surface of buckling load of laminated composites. Many evaluations for genetic algorithms for stacking sequence optimizations require high computational cost. That evaluation cost can be reduced by an approximation using a response surface. For a response surface for stacking sequence optimizations, lamination parameters are adopted as variables of the approximation function of the entire design space instead of ply angles for each ply. This study presents, proposes and investigates a new method of experimental design in detail. For most analytical tools, stacking sequences is demand as input data and lamination parameters cannot be applied directly to the tools. Therefore, the present study proposes and applies a new D-optimal set of laminates to the stacking sequence optimizations of the problem of maximization of buckling load of a composite cylinder. The new experimental design is a set of stacking sequences selected from candidate stacks using D-optimality. Consequently, the D-optimal set of laminates is shown to be effective for design of experiments of response surfaces for maximization of the buckling load of composite structures.     

An object-oriented database system Jasmine: implementation,application, and extension

We have devised an object oriented DBMS called Jasmine for advanced applications. The paper describes the implementation, application and extension of Jasmine in detail. We focus on the impact of the design of its object oriented model and language on database implementation technology. We describe what part of traditional relational database technology we extend to handle object oriented features such as object identifiers, complex objects, class hierarchies, and methods. We introduce nested relations to efficiently store and access clustered complex objects. We use hash based methods to efficiently access nonclustered complex objects. We provide user defined functions directly evaluated on page buffers to efficiently process method invocation. We devise object oriented optimization of queries including class hierarchies, complex objects, and method invocation. We incorporate dedicated object buffering to allow efficient access to objects through object identifiers. We also describe nontrivial applications of Jasmine and discuss the validity of object oriented databases. We focus on a constraint management facility, which can be implemented by taking advantage of the extensibility of Jasmine. The facility includes constraint rules, called design goals, for automatic database population required by engineering applications. Finally, we describe a view facility for schema integration also needed by engineering applications in distributed environments. We focus on how we extend Jasmine to implement the facility     

ARSlice: Head-Mounted Display Augmented with Dynamic Tracking and Projection

Computed tomography (CT) generates cross-sectional images of the body. Visualizing CT images has been a challenging problem. The emergence of the augmented and virtual reality technology has provided promising solutions. However, existing solutions suffer from tethered display or wireless transmission latency. In this paper, we present ARSlice, a proof-of-concept prototype that can visualize CT images in an untethered manner without wireless transmission latency. Our ARSlice prototype consists of two parts, the user end and the projector end. By employing dynamic tracking and projection, the projector end can track the user-end equipment and project CT images onto it in real time. The user-end equipment is responsible for displaying these CT images into the 3D space. Its main feature is that the user-end equipment is a pure optical device with light weight, low cost, and no energy consumption. Our experiments demonstrate that our ARSlice prototype provides part of six degrees of freedom for the user, and a high frame rate. By interactively visualizing CT images into the 3D space, our ARSlice prototype can help untrained users better understand that CT images are slices of a body.     

Functional and Structural Insights into Human PPARα/δ/γ Subtype Selectivity of Bezafibrate,Fenofibric Acid,and Pemafibrate

Among the agonists against three peroxisome proliferator-activated receptor (PPAR) subtypes, those against PPARα (fibrates) and PPARγ (glitazones) are currently used to treat dyslipidemia and type 2 diabetes, respectively, whereas PPARδ agonists are expected to be the next-generation metabolic disease drug. In addition, some dual/pan PPAR agonists are currently being investigated via clinical trials as one of the first curative drugs against nonalcoholic fatty liver disease (NAFLD). Because PPARα/δ/γ share considerable amino acid identity and three-dimensional structures, especially in ligand-binding domains (LBDs), clinically approved fibrates, such as bezafibrate, fenofibric acid, and pemafibrate, could also act on PPARδ/γ when used as anti-NAFLD drugs. Therefore, this study examined their PPARα/δ/γ selectivity using three independent assays—a dual luciferase-based GAL4 transactivation assay for COS-7 cells, time-resolved fluorescence resonance energy transfer-based coactivator recruitment assay, and circular dichroism spectroscopy-based thermostability assay. Although the efficacy and efficiency highly varied between agonists, assay types, and PPAR subtypes, the three fibrates, except fenofibric acid that did not affect PPARδ-mediated transactivation and coactivator recruitment, activated all PPAR subtypes in those assays. Furthermore, we aimed to obtain cocrystal structures of PPARδ/γ-LBD and the three fibrates via X-ray diffraction and versatile crystallization methods, which we recently used to obtain 34 structures of PPARα-LBD cocrystallized with 17 ligands, including the fibrates. We herein reveal five novel high-resolution structures of PPARδ/γ–bezafibrate, PPARγ–fenofibric acid, and PPARδ/γ–pemafibrate, thereby providing the molecular basis for their application beyond dyslipidemia treatment.