The diversification of proto-cells driven by membrane permselectivity

We consider how permselectivity as a function of the membrane is related to the cell evolution with an abstract proto-cell model. We construct an autopoietic proto-cell model having primitive auto-catalytic reaction cycle inside. In this model, several primitive membrane substances are assumed to be produced from the reaction cycle and the membrane is assumed to have a permeability to specific chemical species. We show that the permselectivity of the membrane induces the diversification of the cell volume. We discuss how the diversification of the cells is related to the Darwinian evolution. This work was presented in part and awarded as Young Author Award at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Changes in the surface compositions of FeCr alloys caused by heating in a high vacuum

The change in the alloy surface by heating in a vacuum up to 380°C has been studied for a series of iron—chromium alloys by means of X-ray photo-electron spectroscopy (XPS). Remarkable enrichment of chromium occurs in surface films on the alloys containing 13 % chromium or more. Dependence of composition and thickness of film and composition of alloy surface directly beneath the film on alloy composition has been examined in detail and has been interpreted in terms of the oxidation of chromium and the conversion of the pre-existing surface film, such as decomposition of the oxyhydroxide-like structure and reduction of oxidized iron.     

XPS study of surface film on nickel alloys in hot concentrated NaOH

X-ray photo-electron spectroscopy has been used to investigate the composition of surface films formed on Alloy 600 and Alloy 800 in 50wt. %NaOH at 120°C as a function of polarization potential. Anodic polarization from the corrosion potential successively revealed the active, primary passive, transpassive and secondary passive regions. The formation of hydrated chromium oxy-hydroxide resulted in the primary passivation; the chromium content in the passive film increased with the rise in potential. The transpassive reaction led to an abrupt decrease of chromium in the film with a consequent increase in nickel. The secondary passive film was composed exclusively of nickel hydroxide which transformed to hydrated nickelous oxy-hydroxide with an increase in potential.     

Fiber-optic subscriber loop systems for integrated services--The strategy for introducing fibers into the subscriber network

Two approaches to fiber-optic subscriber loop system development in Japan are described. In the first. Approach I, NTT aims at introducing inexpensive fiber-optic subscriber loop systems using conventional LED's, multimode fiber, and analog transmission techniques in the near future. In the second, Approach II, fiber-optic subscriber loop systems will be made highly functional by evolving from analog to digital transmission. This paper presents system fabrication examples for each approach and the results obtained in the tests.     

Human-following mobile robot in a distributed intelligent sensor network

The robots that will be needed in the near future are human-friendly robots that are able to coexist with humans and support humans effectively. To realize this, humans and robots need to be in close proximity to each other as much as possible. Moreover, it is necessary for their interactions to occur naturally. It is desirable for a robot to carry out human following, as one of the human-affinitive movements. The human-following robot requires several techniques: the recognition of the target human, the recognition of the environment around the robot, and the control strategy for following a human stably. In this research, an intelligent environment is used in order to achieve these goals. An intelligent environment is a space in which many sensors and intelligent devices are distributed. Mobile robots exist in this space as physical agents providing humans with services. A mobile robot is controlled to follow a walking human using distributed intelligent sensors as stably and precisely as possible. The control law based on the virtual spring model is proposed to mitigate the difference of movement between the human and the mobile robot. The proposed control law is applied to the intelligent environment and its performance is verified by the computer simulation and the experiment.     

High drive current NMOS with Si-SiGe heterostructure low electric field channel

A drive-current enhancement in NMOS with a compressively strained SiGe structure, which had been a difficult challenge for CMOS integration with strained SiGe high-hole-mobility PMOS, was successfully achieved using a Si-SiGe heterostructure low electric field channel of optimum thickness. A 4-nm-thick Si low-field-channel NMOS with a 4-nm-thick Si/sub 0.8/Ge/sub 0.2/ layer improved drive current by 10% with a 20% reduction in gate leakage current compared with Si-control, while suppressing threshold-voltage rolloff characteristic degradation, and demonstrated excellent I/sub on/--I/sub off/ characteristics of I/sub on/ = 1 mA//spl mu/m for I/sub off/ = 100 nA//spl mu/m. These results are the best in ever reported NMOS with a compressively strained SiGe structure and indicate that a Si-SiGe heterostructure low-field-channel NMOS integrated with a compressively strained SiGe channel PMOS is a promising candidate for high-speed CMOS in 65-nm node logic technology.     

Inflammatory Biomarkers as Differential Predictors of Antidepressant Response

Although antidepressants are generally effective in the treatment of major depressive disorder (MDD), it can still take weeks before patients feel the full antidepressant effects. Despite the efficacy of standard treatments, approximately two-thirds of patients with MDD fail to respond to pharmacotherapy. Therefore, the identification of blood biomarkers that can predict the treatment response to antidepressants would be highly useful in order to improve this situation. This article discusses inflammatory molecules as predictive biomarkers for antidepressant responses to several classes of antidepressants, including the N-methyl-d-aspartate (NMDA) receptor antagonist ketamine.     

Reaction mechanism in Ti–SiC–C powder mixture during pulse discharge sintering

During pulse discharge sintering (PDS) of Ti/SiC/C powder mixture, combustion synthesis reactions occurred at heating rates above 20 °C/min. With an increase in heating rate, combustion synthesis occurred at higher temperatures. The essential of this combustion reaction is the liquid reaction between Ti and formed Ti₅Si₃. The exothermic TiC formation during PDS process promotes this liquid reaction. We have found that the combustion reactions alone did not finish the formation reactions for Ti₃SiC₂, and further heating following the combustion reactions is necessary for the synthesis process of Ti₃SiC₂.     

Active Polymer Gel Actuators

Many kinds of stimuli-responsive polymer and gels have been developed and applied to biomimetic actuators or artificial muscles. Electroactive polymers that change shape when stimulated electrically seem to be particularly promising. In all cases, however, the mechanical motion is driven by external stimuli, for example, reversing the direction of electric field. On the other hand, many living organisms can generate an autonomous motion without external driving stimuli like self-beating of heart muscles. Here we show a novel biomimetic gel actuator that can walk spontaneously with a worm-like motion without switching of external stimuli. The self-oscillating motion is produced by dissipating chemical energy of oscillating reaction. Although the gel is completely composed of synthetic polymer, it shows autonomous motion as if it were alive.