The Emi2 Protein of Saccharomyces cerevisiae is a Hexokinase Expressed under Glucose Limitation

Hexokinases catalyze glucose phosphorylation at the first step in glycolysis in eukaryotes. In the budding yeast Saccharomyces cerevisiae , three enzymes for glucose phosphorylation have long been known: Hxk1, Hxk2, and Glk1. In this study, we focus on Emi2, a previously uncharacterized hexokinase-like protein of S. cerevisiae . Our data show that the recombinant Emi2 protein (rEmi2), expressed in Escherichia coli , possesses glucose-phosphorylating activity in the presence of ATP and Mg ²⁺ . It was also found that rEmi2 phosphorylates not only glucose but also fructose, mannose and glucosamine in vitro . In addition, we examined changes in the level of endogenous Emi2 protein in S. cerevisiae in the presence or absence of glucose and a non-fermentable carbon source. We found that the expression of Emi2 protein is tightly suppressed during proliferation in high glucose, while it is strongly upregulated in response to glucose limitation and the presence of a non-fermentable carbon source. Our data suggest that the expression of the endogenous Emi2 protein in S. cerevisiae is regulated under the control of Hxk2 in response to glucose availability in the environment.     

Calculation of the Characteristics of Salient‐Pole Synchronous Machines Assisted by Permanent Magnets on the Basis of the Operating Principle

In this study we investigate a method for accurately calculating the characteristics of salient‐pole synchronous machines assisted by permanent magnets. First, the operating principle of the machines is investigated by using both finite element analysis and a simple magnetic circuit. Then, a theoretical representation of the assist effect on the permanent magnets is derived based on the magnetic circuit. Finally, the measured and calculated results are compared in order to confirm the validity of the proposed calculation method. We show that the load characteristics of the proposed machine can be accurately estimated from the no‐load and short‐circuit characteristics of the conventional machine without permanent magnets, and the size and magnetization of the inserted permanent magnets.     

Application of Near-Infrared Spectroscopy for Evaluation of Drying Stress on Lumber Surface: A Comparison of Artificial Neural Networks and Partial Least Squares Regression

This study aimed to examine the feasibility of evaluating the stress level at the surface of lumber during drying using near-infrared (NIR) spectroscopy combined with artificial neural networks (ANNs). Sugi (Cryptomeria japonica D. Don) lumber with an initial moisture content ranging from 41.1 to 85.8% was dried using a commercial drying schedule. An ANN model for predicting surface-released strain (SRS) was developed based on NIR spectra collected from the lumber during drying. The predictive ability of the ANN model was compared with a partial least squares (PLS) regression model.

The ANN model showed good correlation between laboratory-measured SRS and predicted SRS with an R ² of 0.79, a root mean square error of prediction (RMSEP) of 0.0009, and a ratio of performance to deviation (RPD) of 1.81. The PLS regression model gave a lower R ² of 0.69, a higher RMSEP of 0.0010, and a lower RPD of 1.38 than the ANN model, suggesting that the predictive performance of the ANN model was superior to the PLS regression model. The SRS evolution during drying as predicted by the models showed a similar trend to the laboratory-measured one. The predicted elapsed times to reach maximum tensile SRS and stress reversal roughly coincided with the laboratory-measured times. These results suggest that NIR spectroscopy combined with multivariate analysis has the potential to predict the drying stress level on the lumber surface and the critical periods during drying, such as the points of maximum tensile stress and stress reversal.     

Dynamic mechanical properties of three‐component composites (acrylic polymer/epoxy/SiO2) in the glass‐transition region

In previous studies, we reported the linear and nonlinear rheological properties of three‐component composites consisting of acrylic polymer (AP), epoxy resin (EP), and various SiO₂ contents (AP/EP/SiO₂) in the molten state. In this study, the dynamic mechanical properties of AP/EP/SiO₂ composites with different particle sizes (0.5 and 8 μm) were investigated in the glass‐transition region. The EP consisted of three kinds of EP components. The α relaxation due to the glass transition shifted to a higher temperature with an increase in the volume fraction (?) for the AP/EP/SiO₂ composites having a particle size of 0.5 μm, but the α relaxation scarcely shifted for the composite having a particle size of 8 μm as a general result. This result suggested that the SiO₂ nanoparticles that were 0.5 μm in size adsorbed a lot of the low‐glass‐transition‐temperature (T_g) component because of their large surface area. The AP/SiO₂ composites did not exhibit a shift in T_g; this indicated that the composite did not adsorb any component. The modulus in the glassy state (E′_g) exhibited a very weak &phis; dependence for the AP/EP/SiO₂ composites having particle sizes of 0.5 and 8 μm, although E′_g of the AP/SiO₂ composites increased with &phis;. The AP/EP/SiO₂ composites exhibited a peculiar dynamic mechanical behavior, although the AP/SiO₂ composites showed the behavior of general two‐component composites. Scanning electron microscopic observations indicated that some components in the EP were adsorbed on the surface of the SiO₂ particles. We concluded that the peculiar behavior of the AP/EP/SiO₂ composites was due to the selective adsorption of the EP component. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40409.     

Surface Analysis of Cr2O3‐, CoO‐, and Al2O3‐Doped Iron–Phosphate Glasses at High Temperature

Surface structures of iron–phosphate glasses were examined using X‐ray photoelectron spectroscopy (XPS). Cr₂O₃, CoO, and Al₂O₃ were introduced to the glass by the replacement of a part of Fe₂O₃, and the simulated fission products are also added. The obtained glasses showed high chemical durabilities by MCC‐1 test. In situ high‐temperature and room‐temperature XPS measurements were conducted on the polished sample surfaces and also those after 1‐week chemical durability test. Unique trends were observed in XPS spectra on heating and after the chemical durability test, respectively. Nature of the glass surface of iron–phosphate glasses was explained from the point of view of surface energy, and the origin of high chemical durability and the effect of chromium ions were discussed based on the changes on surface composition and valence states of transition‐metal ions.     

Water vapor solubility of poly(lactic acid) films modified the surface by vacuum ultraviolet irradiation

Surface modification of poly(lactic acid) (PLA) film is performed via 172 nm excimer lamp irradiation. Effects on water vapor solubility and physical properties via vacuum ultraviolet (VUV) irradiation are studied systematically. After VUV irradiation, water vapor solubility increases approximately 11–43% in the low‐pressure region and approximately 20–38% in the high‐pressure region as surface hydrophilicity increased. The increase is attributed to hydrogen bonding with the carboxyl groups because of VUV radiation. The modified layer is significantly swelling after water vapor sorption. The hydrophilic layer forms a thickness of 2–3 μm from the irradiated surface via VUV radiation, but no changes are observed inside the irradiated film. Therefore, PLA film solubility after irradiation is enhanced by hydrophilicity and the swelling effect of the surface. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42200.     

Eutectic compound (KNO3/NaNO3 : PCM) quasi‐encapsulated into SiC‐honeycomb for suppressing natural convection of melted PCM

The phase change eutectic compound, KNO₃/NaNO₃ (50/50 mol%) (phase change material (PCM)), which is used as the thermal energy storage material in the solar thermal power plant, was quasi‐encapsulated into the SiC‐honeycomb (SCH) for suppressing the natural convection occurring at the liquid state of PCM. The performance of the SCH as the material suppressing natural convection of PCM was investigated experimentally. PCM with three kinds of mixing ratios of SCH of 10%, 20%, and 30%, was prepared and packed in their respective stainless can with oil‐flowing pipe in the center, which is called thermal energy storage unit (TESU). Three units were linked together and stacked vertically by the connector at the inlet/outlet oil pipe. The time variation of temperature at the fixed positions inside the TESU in charging/discharging process and temperature gradient in the radial direction inside TESU when PCM was liquid state were investigated. It is concluded that the natural convection is suppressed by mixing the SCH with PCM up to around 30% in weight, because the PCM is quasi‐encapsulated into cell holes and porous structures of SCHs. And thus, the heat transfer of the PCM + 30%SCH composite is controlled mainly by its thermal conduction, which is also supported through comparison of simulation result with experimental one. And so, we conclude that SCH has a function as the quasi‐encapsulating material for suppressing the natural convection of PCM. Copyright © 2015 John Wiley & Sons, Ltd.     

Predicting the Life Span of Dies Used for Soft Magnetic Core Motors

This paper describes a method of predicting the life span of the dies used in motor manufacture from soft magnetic composites (SMCs). In the present study, a clawtooth motor was used. The method involves performing a stress analysis of a die followed by fatigue testing of test pieces. In the analysis, the SMC was assumed to be in powder form and its yield function was derived by a simple method. In addition to the analysis, we describe a simpler and more effective method in which the properties of the SMC are treated as boundary conditions. In the fatigue tests, we used test pieces that simulated the shape and construction material of the die. To predict the life span of the die, we evaluate the SN diagram, which represents the relationship between the maximum stress and fatigue life with respect to the stress generated in the die. The life expectancy of a new die, which is about 100 cycles of use, is found to agree substantially with its actual life. Furthermore, we explain how to extend the life span of a die to the targeted life span, namely, more than 200,000 cycles of use, by changing its shape to reduce stress.