Model reference adaptive control system design for linear time‐varying systems with unstructured and bounded varying functions

In recent years, many methods of model reference adaptive control system (MRACS) for a linear time‐varying (LTV) plant have been proposed. These methods assumed that the structure of plant parameters is known in advance. However, it is difficult to get a priori information of plant parameters. In this paper, an MRACS design for an LTV system based on high‐order estimator (HOE) is proposed. By applying dynamic certainty equivalence (DyCE) to LTV plants, a new MRAC law of LTV system is derived without knowing the structure of the plant parameters. The MRACS law is generated by using high‐order derivatives of an estimated parameter, so that robust HOE with a normalization signal and σ modification for the system introduced. Our proposed method can attain better performance than conventional methods, such as estimation with variable forgetting factor (VF) and the gradient projection method (GPM). The robust HOE establishes the boundedness of all of the estimated parameters under the condition that the estimated parameter and the first derivative of the parameter are bounded. It is shown that all signals in the adaptive loop are bounded and the output error converges to a closed set. The proposed method is compared to the familiar schemes, the gradient projection method and the estimation based on forgetting factor through numerical simulations, and the effectiveness of our proposed method is shown. © 2000 Scripta Technica, Electr Eng Jpn, 130(4): 87–98, 2000     

Fast acquisition system for digital holograms and image processing for three-dimensional display with data manipulation

A three-dimensional (3D) digital holographic display system with image processing is presented. By use of phase-shifting digital holography, we obtain the complex amplitude of a 3D object at a recording plane. Image processing techniques are introduced to improve the quality of the reconstructed 3D object or manipulate 3D objects for elimination and addition of information by modifying the complex amplitude. The results show that the information processing is effective in such manipulations of 3D objects. We also show a fast recording system of 3D objects based on phase-shifting digital holography for display with image processing. The acquisition of 3D object information at 500 Hz is demonstrated experimentally.     

Complementation analysis reveals a potential role of human ARV1 in GPI anchor biosynthesis

ARV1 is involved in regulating lipid homeostasis but also in the biosynthesis of glycosylphosphatidylinositol (GPI) in Saccharomyces cerevisiae. Here, we examined whether human ARV1 can complement the role of yeast ARV1 in GPI biosynthesis. Overexpression of human ARV1 could rescue the phenotypes associated with GPI anchor synthesis defect in the yeast arv1Δ mutant. The results suggest that Arv1 function in GPI biosynthesis may be conserved in all eukaryotes, from yeast to humans. Copyright © 2015 John Wiley & Sons, Ltd.     

Optical authentication method using a three-dimensional phase object with various wavelength readouts

An optical system for authentication using a 3D (3D) random phase object with various wavelength readouts is proposed. The 3D phase object without surface modulation is secure when the scattering is strong enough because it prevents from the interferometric measurement. The identification is implemented by the correlation between a measured speckle pattern of the 3D phase object and stored speckle patterns. For accurate identification, two speckle patterns of the 3D object obtained by illuminating two wavelengths are used. Experimental demonstrations and numerical evaluations of wavelength selectivity are presented.     

Three-dimensional measurement and imaging based on multicameras randomly distributed on the circumference

We present a three-dimensional (3D) measurement and imaging based on a multicamera system. In the presented system, projected images of 3D objects are taken by cameras located at random positions on a circumference, and then the 3D objects can be reconstructed numerically. We introduce an angle correction function to improve the quality of the reconstructed object. The angle correction function can correct the angle error caused by the position errors in the projected images due to the finite pixel size of the image sensor. The numerical results show that the point source was reconstructed successfully by introducing the angle correction function. We also demonstrate experiments: the two objects are located on a rotary stage controlled by a computer, the projected images are taken by a single camera, and by using 33 projected images, the two objects are reconstructed successfully.     

Tip-enhanced Rayleigh scattering and photoluminescence from semiconductor nanoparticles

Tip-enhanced Rayleigh scattering images of Ge quantum dots grown on a Si substrate have been observed at room temperature. Changing the wavelength of the incidence light from 405 to 590 nm, the contrast of the images is reversed. It is found that the scattering intensity depends on the dielectric constants of the materials under the probe. By changing the wavelength of the incident light, we have obtained information about the dielectric constant dispersion of single Ge quantum dots. The spectral peak position of single Ge quantum dots is found to shift to higher energy, compared to that of bulk Ge. Tip-enhanced photoluminescence from an In0.25Ga0.75N film at room temperature has also been reported. The strong local enhancement of the photoluminescence of the localized excitons has been observed in the vicinity of a gold nano-particle attached to the end of the probe. A coupling to plasmons in the gold nano-particle yields strong enhancement of the photoluminescence.     

Influence of side chain length on fluorescence intensity of ROMP-based polymeric nanoparticles and their tumor specificity in in-vivo tumor imaging

In this study, amphiphilic brush-like copolymers conjugated with short alkyl or long polymeric chains of various lengths are synthesized using ring-opening metathesis polymerization (ROMP) of substituted norbornadiene monomers followed by chemical transformations. These amphiphilic copolymers form spherical self-assemblies in aqueous media with diameters of 132-244 nm. The low critical aggregation concentration of these assemblies (2.5 × 10(-3) -1.4 × 10(-5) g/L) indicates that they are quite stable in dilute conditions. An appropriate length of polymer side chain that conjugates the polymer backbone with a hydrophobic ICG (indocyanine green) moiety enhanced the fluorescence intensities of these self-assemblies in aqueous solution as well as in tumor-bearing mice. A longer side chain conjugated with tumor targeting agents could significantly affect the tumor specificity of self-assemblies to a greater extent. The self-assemblies bearing hydrophilic tumor targeting agents, such as a glucosamine molecule and a cyclic RGD (arginine-glycine-asparatic acid) peptide, accumulated in tumor tissues with high selectivity, while those having a hydrophobic targeting agent, such as folate moieties, accumulated in tumor sites with low selectivity. The results demonstrated here unambiguously indicate that the fluorescence intensity and tumor specificity of self-assemblies are strongly affected by the length of side chains that conjugate with dyes and targeting agents.     

Microstructural degradation mechanisms during creep in strength enhanced high Cr ferritic steels and their evaluation by hardness measurement

There are two creep regions with different creep characteristics: short-term creep region “H”, where precipitates and subgrains are thermally stable, and long-term creep region “L”, where thermal coarsening of precipitates and subgrains appear. In region “H”, the normalized subgrain size (λ-λ₀)/(λ^∗-λ₀) has a linear relation with creep strain and its slope is 10ε⁻¹. But, region L is the time range in which the static recovery and the strain-induced recovery progress simultaneously. In this region, the static recovery accelerates the strain-induced recovery, and subgrain size is larger than that line which neglects the contribution of the static recovery. In region “L”, the Δλ/Δλ^∗-strain present a linear relation with a slope 35ε⁻¹. There is a linear relation between hardness and subgrain size. Hardness drop, H₀ − H, as a function of Larson-Miller parameter can be a good measure method for assessment of hardness drop and consequently degradation of microstructure. Hardness drop shows an identical slope in creep region “H”, whereas hardness drop due to thermal aging and creep in region “L” show together a similar slope. In region “H”, degradation of microstructure is mainly due to recovery of subgrains controlled by creep plastic deformation, and precipitates do not have a major role. However, in creep region “L”, there are three degradation mechanisms that accelerate creep failure; (1) strain-induced recovery of subgrains due to creep plastic deformation, (2) static-recovery of subgrains and precipitates and (3) strain-induced coarsening of precipitates due to the appearance of static-recovery.     

Beneficial Effects of Supplementation of the Rare Sugar “D‐allulose” Against Hepatic Steatosis and Severe Obesity in Lepob/Lepob Mice

A rare sugar, D‐allulose (also called D‐psicose), has recently been applied as a food supplement in view of controlling diabetes and obesity in Japan. D‐allulose has been proven to have unique effects against hyperglycemia and hyperlipidemia in a number of studies using several species of rats and mice. However, the antiobesity effects of D‐allulose have not yet been assessed in Lep^ob/Lep^ob (ob/ob) mice. Therefore, this study explored the dietary supplemental effects of this sugar in leptin‐deficient ob/ob mice. Consequently, the subchronic ingestion of D‐allulose in ob/ob mice for 15 wk significantly decreased the body and liver weights, and the loss of body weight was involved in the reduction of the total fat mass, including abdominal visceral fat, and not fat‐free body mass, including muscle. Furthermore, D‐allulose improved hepatic steatosis, as evaluated using hepatic histological studies and MRI. In the normal mice, none of these parameters were influenced by the single or long‐term ingestion of D‐allulose. These results indicate that dietary supplementation of D‐allulose especially influences postprandial hyperglycemia and obesity‐related hepatic steatosis, without exercise therapy or dietary restriction. Therefore, D‐allulose may be useful as a supplement for preventing and improving obesity and obesity‐related disorders.