Cloning of a novel signal-transducing adaptor molecule containing an SH3 domain and ITAM

We molecularly cloned a cDNA coding for a novel phosphotyrosine molecule with a 70 kDa molecular mass, named STAM (signal transducing adaptor molecule), which is tyrosine-phosphorylated rapidly after stimulation with various cytokines such as IL-2, IL-3, IL-4, IL-7, GM-CSF, EGF and PDGF. STAM contains an SH3 (Src-homology 3) domain and the ITAM (immunoreceptor tyrosine-based activation motif), suggesting that STAM acts as an adaptor molecule involved in signal transducing pathways from the cytokine receptors.     

Input information maximization for improving self-organizing maps

In this paper, we propose a new type of information-theoretic method called “input information maximization” to improve the performance of self-organizing maps. We consider outputs from input neurons by focusing on winning neurons. The outputs are based on the difference between input neurons and the corresponding winning neurons. Then, we compute the uncertainty of input neurons by normalizing the outputs. Input information is defined as a decrease in the uncertainty of input neurons from a maximum and observed value. When input information increases, fewer input neurons tend to be activated. In the maximum state, only one neuron is on, and all others are off. We applied the method to two data sets, namely, the Senate and voting attitude data sets. In both, experimental results confirmed that when input information increased, quantization and topographic errors decreased. In addition, clearer class structure could be extracted by increasing input information. In comparison to our previous methods to detect the importance of input neurons, the present method turned out to be good at producing faithful representations with much more simplified computational procedures.     

Understanding heterogeneous catalysis on an atomic scale: a combined surface science and reactivity investigation for the dehydrogenation of ethylbenzene over iron oxide catalysts

In order to study the dehydrogenation of ethylbenzene to styrene, epitaxial iron oxide model catalyst films with Fe₃O₄(111), -Fe₂O₃(0001) and KFe _x O _y (111) stoichiometry were prepared in single crystal quality on Pt(111). They were investigated using surface science techniques before and after atmospheric pressure reaction experiments in a newly designed single crystal flow reactor. As expected from low-pressure measurements, Fe₃O₄(111) is catalytically inactive. The catalytic activity of -Fe₂O₃(0001) starts after an activation period of about 45 min. After that, the surface is essentially clean but shows a high concentration of defects. On the potassium-promoted films, however, the activation period is much longer, the activity then is higher and the surface gets covered completely with carbon and oxygen during reaction. This indicates a different reaction pathway on the promoted films with a carbon–oxygen species as catalytically active species.     

Synthesis of High Density and Transparent Forsterite Ceramics Using Nano-Sized Precursors and Their Dielectric Properties

Forsterite (Mg₂SiO₄) ceramics were prepared using Mg(OH)₂ and SiO₂ as precursors, and the effect of powder characteristics of Mg(OH)₂ on calcination and sintering was investigated. The use of highly dispersed Mg(OH)₂ powder (HD powder) resulted in a lower calcination temperature. Forsterite powder of high homogeneity and small particle size prepared from the HD powder enabled synthesis of high-density forsterite ceramics by ordinary sintering without applying external pressure. Moreover, transparent forsterite ceramics were successfully synthesized through addition of excess Mg to the precursors to compensate for Mg evaporated during the sintering process. Subsequent dielectric measurements revealed that the transparent forsterite ceramics had a very low dielectric loss (tan δ<10⁻⁴).     

Information-Theoretic Competitive Learning with Inverse Euclidean Distance Output Units

In this paper, we propose a new information theoretic competitive learning method. We first construct a learning method in single-layered networks, and then we extend it to supervised multi-layered networks. Competitive unit outputs are computed by the inverse of Euclidean distance between input patterns and connection weights. As distance is smaller, competitive unit outputs are stronger. In realizing competition, neither the winner-take-all algorithm nor the lateral inhibition is used. Instead, the new method is based upon mutual information maximization between input patterns and competitive units. In maximizing mutual information, the entropy of competitive units is increased as much as possible. This means that all competitive units must equally be used in our framework. Thus, no under-utilized neurons or dead neurons are generated. When using multi-layered networks, we can improve noise-tolerance performance by unifying information maximization and minimization. We applied our method with single-layered networks to a simple artificial data problem and an actual road classification problem. In both cases, experimental results confirmed that the new method can produce the final solutions almost independently of initial conditions, and classification performance is significantly improved. Then, we used multi-layered networks, and applied them to a character recognition problem and a political data analysis. In these problem, we could show that noise-tolerance performance was improved by decreasing information content on input patterns to certain points.     

Effect of α-substituents on molecular motion and wetting behaviors of poly(fluoroalkyl acrylate) thin films with short fluoroalkyl side chains

The effect of α-substituent on the molecular motion and wetting behavior of poly{2-(perfluorobutyl)ethyl acrylate} [PFA-C₄], poly{2-(perfluorobutyl)ethyl methacrylate} [PFMA-C₄], poly{2-(perfluorobutyl)ethyl α-fluoroacrylate} [PFFA-C₄], and poly{2-(perfluorobutyl)ethyl α-chloroacrylate} [PFClA-C₄] films were characterized by dynamic contact angle measurement, lateral force microscopy (LFM), wide angle X-ray diffraction (WAXD), and X-ray photoelectron spectroscopy (XPS). WAXD of oriented PFClA-C₄ fiber suggested the presence of rod-like chain due to the presence of bulky α-substituent. The glass transition temperature (T_g) of PFFA-C₄ and PFClA-C₄ were well above the room temperature. The water repellencies of PFFA-C₄ and PFClA-C₄ were as high as that of PFMA-C₄ and their oil repellency of PFFA-C₄ and PFClA-C₄ was higher than the PFMA-C_4. This result was originated from the low main chain mobility of PFFA-C₄ and PFClA-C₄ due to the presence of bulky α-substituents. The effect of molecular motion on water repellency was clarified by the results of temperature dependence studies of dynamic contact angle, LFM, and surface chemical composition measured by XPS.     

Selective preparation of oligomeric naphthylene ether and its applications to epoxy resin for silicon carbide power semiconductor device materials

In this study, a novel method for selective synthesis of naphthylene ether trimers by self‐condensation of 2,7‐dihydroxynaphthalene in the presence of catalytic amount of potassium hydroxide was reported. An epoxy resin from the trimers was prepared and properties of the cured epoxy resin were examined. The cured resin showed not only good physical thermal stability, such as high glass transition temperature and low thermal expansion coefficient, but also good chemical thermal stability like high thermal decomposition temperature. Additionally, low moisture absorption of the cured resin was confirmed. From these results, the newly prepared epoxy resin with naphthylene ether skeletons was considered to be suitable for advanced applications such as silicon carbide power semiconductor device. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43339.     

Why we talk?: altruism and multilevel selection in the origin of language

Talking entails costs of production and time, although some of the information sent to hearers will be of value to them in general. We believe that the matter of why we talk at all is a key question for the origin of language, and the answer will shed some light on the mystery of human identity. This article focuses on altruism in communication, and aims to demonstrate evolutionary scenarios based on multilevel selection. We constructed a computational model to examine these scenarios. The evolutionary experiments showed that in the case of an unstructured population, a linguistic system hardly emerged due to the dynamics between interpretable utterance that imposes a penalty and correct interpretation that yields a reward, which is similar to prey-predator dynamics. However, in the case of a multigroup population, a linguistic system emerged owing to multilevel selection among the groups. In addition, the probability of success in conversation was higher in a group in more severe environmental conditions. This result supports Bickerton’s hypothesis based on the ecological gap between human ancestors and other ape species.     

Single-Electron Device With Si Nanodot Array and Multiple Input Gates

We have developed a flexible-logic-gate single-electron device (SED) with an array of nanodots. Although the small size of SEDs is highly advantageous, the size of the nanodots inevitably fluctuates, which causes variations in device characteristics. This variability can be eliminated and high device functionality can be obtained by exploiting the oscillatory characteristics and multigate capability of SEDs. We fabricated, on a silicon-on-insulator wafer, a Si nanodot array device with two input gates and a control gate and investigated its basic operation characteristics experimentally. The device was demonstrated to operate as a logic gate providing six important logic functions ( and, or, nand, nor, xor, and xnor), which are obtained by adjusting the control-gate voltage.