Coherent Electron Transport in Air-Stable,Printed Single-Crystal Organic Semiconductor and Application to Megahertz Transistors

Organic semiconductors (OSCs) have attracted growing attention for optoelectronic applications such as field-effect transistors (FETs), and coherent (or band-like) carrier transport properties in OSC single crystals (SCs) have been of interest as they can lead to high carrier mobilities. Recently, such p-type OSC SCs compatible with a printing technology have been used to achieve high-speed FETs; therefore, developments of n-type counterparts may be promising for realizing high-speed complementary organic circuits. Herein, coherent electron transport properties in a printed SC of a state-of-the-art, air-stable n-type OSC, PhC₂−BQQDI, by means of variable-temperature gated Hall effect measurements and X-ray single-crystal diffraction analyses in conjunction with band structure calculations, are reported. Furthermore, the SC FET is tested for high-speed operations, which obtains a cutoff frequency of 4.3 MHz at an operation voltage of 20 V in air. Thus, PhC₂−BQQDI is shown as a new candidate for practical applications of SC-based, organic complementary devices.     

Effect of particles and interface conditions on fibrous tissue interposition between bone and implant. A particle challenge model in rabbit

Interposed fibrous tissue at bone–implant interfaces was quantitatively measured in the presence or absence of polyethylene (PE) or alumina particles. Three different conditions of the interface were designed by implanting a pre-polymerized polymethylmethacrylate (PMMA) plug (plug group), a doughy PMMA (injection group) and a hydroxyapatite (HA) plug (HA group) in the hole drilled at the intercondylar notch of rabbit knees. PE (170±18 m) or alumina particles (88±26 m) were repeatedly administered into the knee joints at one month intervals (six times). All animals were sacrificed seven months after the implantation. The bone–implant interface was histomorphometrically examined using undecalcified ground sections. In the plug group, the PE particles significantly increased the extent of the interposed fibrous tissue (p < 0.05), while the alumina particles showed no effect. In contrast, both particles showed no significant effects in the injection and the HA groups. These results indicate that both particle characteristics and conditions of the bone–implant interface affected particle-induced fibrous tissue interposition. The loose PMMA plug with PE particles induced the greatest amount of fibrous tissue interposition. ©2000 Kluwer Academic Publishers     

Autonomous and distributed mobility management in mobile core networks

The 5th generation mobile and wireless communication systems are expected to accommodate exploding traffic, increasing number of devices, and heterogeneous applications driven by proliferation of IoT and M2M technologies. However, the centralized mobility management architecture in a current mobile core network would face critical problems such as excessive concentration of load on specific servers and considerable increase in C-plane overhead. To solve the problems we first consider a novel architecture of distributed mobility management in C-plane in the mobile core network, which employs virtualized mobility management entity called ADMMEs (Autonomous Distributed Mobility Management Entity) in this paper. In addition, to assign an appropriate ADMME to a UE in accordance with mobility characteristics of the UE and a management policy, we propose an autonomous and adaptive ADMME selection scheme. We adopt a biologically-inspired algorithm, called attractor selection, to accomplish adaptive selection taking into account multiple objectives. Through simulation experiments, we confirmed our proposal could accomplish more than 63 % performance improvement comparing to the current method from viewpoints of delay, load balancing, and C-plane overhead under a dynamic mobility scenario.     

Increase in breakdown strength of PE film by additives ofazocompounds

PE films with various additives were prepared by the solution-grown method. The thickness of the films ranged from 5 to 25 μm. Six different azocompounds were used as additives. The results show that BDS 0 for the film with additives was higher than that for the film without additives in the temperature range from -35 to 30°C. The increasing ratio of BDS depended on the composition of the additives used. Our results indicate that the breakdown of the film is induced by an electron avalanche. The conduction current through the film in the high electric field region was reduced by using the additives. The dependence of the conduction current on additives corresponds to that of BDS; a higher BDS is realized for films with additives by which the conductive current is controlled at the lower value. It was considered that the reduction of current by the additive is due to either the trapping effect or the excitation effect of the additive. The trap level for the additive and the excitation energy depend upon the type of radical connected on the benzene ring of the additive: electron-accepting or electron-donating type. The results suggested that high BDS and small current are obtained when the azocompound on which the electron-accepting radical is connected is used as the additive     

Cooperative Control of a 3D Dual-Flexible-Arm Robot

This paper discusses cooperative control of a dual-flexible-arm robot to handle a rigid object in three-dimensional space. The proposed control scheme integrates hybrid position/force control and vibration suppression control. To derive the control scheme, kinematics and dynamics of the robot when it forms a closed kinematic chain is discussed. Kinematics is described using workspace force, velocity and position vectors, and hybrid position/force control is extended from that on dual-rigid-arm robots. Dynamics is derived from constraint conditions and the lumped-mass-spring model of the flexible robots and an object. The vibration suppression control is calculated from the deflections of the flexible links and the dynamics. Experiments on cooperative control are performed. The absolute positions/orientations and internal forces/moments are controlled using the robot, each arm of which has two flexible links, seven joints and a force/torque sensor. The results illustrate that the robot handled the rigid object damping links' vibration successfully in three-dimensional space.     

Determination of mechanical properties of impacted human morsellized cancellous allografts for revision joint arthroplasty

This paper deals with the characterization of mechanical properties of impacted morsellized cancellous allograft (IMCA) produced by dynamic compaction of allograft femoral heads ground by commercially available bone mills, i.e. rotating rasp and reciprocating type bone mills. Various ranges and profiles of particle size in the graft aggregates were obtained using these bone mills, and the effect of number of compaction as well as the distribution of particle sizes on the mechanical properties of IMCA under quasistatic compression and shear loading conditions was discussed. The morsellized cancellous allograft prepared by the reciprocating type bone mill showed a broad distribution of particle sizes, and gave IMCA superior mechanical properties to the graft with a more uniform size distribution, or prepared by the rotating rasp type bone mills. The increase of number of compaction also improved the mechanical properties of IMCA in compression.     

Isolation of MHC class I-restricted tumor antigen peptide and its precursors associated with heat shock proteins hsp70, hsp90, and gp96

We have previously demonstrated that vaccination with heat shock proteins hsp70, hsp90, and gp96 elicits specific immunity against the tumor from which the hsps were purified. Although the association of tumor Ag peptides with these hsps have been suggested, the identification of the peptides or their precursors stripped from the hsps remained to be resolved. We show in this report that an Ld-restricted cytotoxic T lymphocyte epitope of a mouse leukemia RLmale symbol1 and its precursors are associated with the chaperones hsp90 and hsp70 in the cytosol and gp96 in the lumen of the endoplasmic reticulum. Hsp70 was associated with only final sized octamer, while hsp90 was found to associate with the octamer and two distinct precursor peptides. The gp96 was associated with the octamer and one of the two precursors. Thus, each of the hsps bound a distinct set of peptides. Our results have demonstrated for the first time that the hsps associate not only with final sized tumor Ag peptide but also with its precursors. The implication of this evidence is also discussed in terms of the roles of hsps in MHC class I Ag processing/presentation.     

Small-scale component experiments of the penetration leak characterization test in the ALPHA program

A small-scale penetration leak characterization test has been performed as a part of the ALPHA program at Japan Atomic Energy Research Institute (JAERI). Two series of experiments were performed using test sections which simulate relevant parts of an EPA (Electrical Penetration Assembly) used in Japanese PWR containments. One of the test sections simulates an alumina module and the other includes the silicone resin portion of the EPA. The test section was heated in a leak test vessel which simulated thermal-hydraulic conditions inside and outside of the containment in a severe accident. From the experimental results, it was concluded that although the silicone resin may melt at high temperature, the alumina module will remain intact under severe accident conditions. The EPA as a whole is estimated to maintain leak-tightness during a severe accident. It was found in the experiments that heat conduction along the metal portion of the test section had a strong influence on the melt progression of the resin. It was also found that the measured strain of the alumina module was predominantly caused by the elevated temperature. Therefore, the thermal load will be more of a threat to the EPA's integrity rather than the pressure load.     

Measurement of emotional reactivity and association ability of the Tsukuba emotional strains of rats (Rattus norvegicus) in licking and lever-pressing conditioned suppression situations.

The emotional reactivity and association ability of the Tsukuba High Emotional (THE), the Tsukuba Low Emotional (TLE), and the Wistar-Imamichi (WI) strains of rats were studied in two experiments. Suppression of licking and lever pressing by unsignaled shocks were used to measure emotionality in Experiments 1 and 2, respectively. Contrary to our expectations, the WI rats which had formed a part of the foundation population of the Tsukuba strains, proved to be the most emotional, and the THE and TLE did not differ in emotionality from each other in either experiment. Association ability was measured by the speed of discriminating dangerous and safe periods under matched levels of emotional arousal. Association ability proved to be best in TLE rats, especially in Experiment 2, in which the procedures were somewhat improved on the basis of the results of Experiment 1. We discuss the results in terms of the motivational system and of the behavioral characteristics established during the course of selective breeding. (PsycINFO Database Record (c) 2010 APA, all rights reserved)