Search

Improving wearing mobility is an important issue for wearable robot mechanisms to provide a person wearing the mechanism with improved efficiency of a task and comfortable wearing feel. For evaluating the wearing mobility, relative motion between the mechanism and a human limb wearing the mechanism is considered to be a major factor, because the mechanism is usually fixed tightly to the limb for the purpose of motion support. This paper assumes motion support of a human elbow, and considers evaluation of wearing mobility of a human arm based on measurement data obtained by a sensor device. Evaluation under definitions of some indexes is discussed in this paper. In addition, two mechanical designs, one of which is considered to be typical in wearable elbow mechanisms, are evaluated and compared from the viewpoint of wearing mobility. The comparison suggests that a mechanical design with parallel linkages has potential of improving wearing mobility.

Objective.Assessing retention rate and risk factor for drug discontinuation is important for drug evaluation. We examined a 3-year retention rate and the risk factor for discontinuation due to insufficient efficacy (IE) and adverse events (AE) in Japanese patients with rheumatoid arthritis (RA) who are receiving etanercept (ETN).Methods.Data were collected from 588 patients treated with ETN as a first biologic from the Tsurumai Biologics Communication Registry. Baseline characteristics for the incidence of both IE and AE were analyzed using the Cox proportional-hazards regression model. Patients were divided into groups based on age and concomitant methotrexate (MTX). Drug retention rates were calculated using the Kaplan-Meier method and compared among groups using the log-rank test.Results.ETN monotherapy without concomitant MTX [MTX(–)] was significantly related to a higher incidence of discontinuation due to IE [hazard ratio (HR) = 2.226, 95% CI 1.363–3.634]. Older age and MTX(–) were significantly related to a higher incidence of discontinuation due to AE [HR = 1.040, 1.746, 95% CI 1.020–1.060, 1.103–2.763, respectively]. The MTX(–)/≥ 65 years group had the lowest retention rate (p < 0.001). The discontinuation rate due to IE was lower in the MTX(+)/< 65 years group compared to < 65 years/MTX(–), ≥ 65 years/MTX(–) group (p = 0.006, p < 0.001, respectively). The discontinuation rate due to AE was highest in the MTX(–)/≥ 65 years group (p < 0.001).Conclusion.Our findings suggest that the risk of discontinuation due to IE was high in the patients who did not use concomitant MTX and that the risk of discontinuation due to AE was high in elderly patients who did not use concomitant MTX.

We have developed a LIDAR system with a sensor head which, although it includes a scanning mechanism, is less than 20 cc in size. The system is not only small, but is also highly sensitive. Our LIDAR system is based on time-of-flight measurements, and incorporates an optical fiber. The main feature of our system is the utilization of optical amplifiers for both the transmitter and the receiver, and the optical amplifiers enable us to exceed the detection limit set by thermal noise. In conventional LIDAR systems the detection limit is determined by the thermal noise, because the avalanche photo-diodes (APD) and trans-impedance amplifiers (TIA) that they use detect the received signals directly. In the case of our LIDAR system, the received signal is amplified by an optical fiber amplifier before reaching the photo diode and the TIA. Therefore, our LIDAR system boosts the signal level before the weak incoming signal is depleted by thermal noise. There are conditions under which the noise figure for the combination of an optical fiber amplifier and a photo diode is superior to the noise figure for an avalanche photo diode. We optimized the gains of the optical fiber amplifier and the TIA in our LIDAR system such that it would be capable of detecting a single photon. As a result, the detection limit of our system is determined by shot noise. We have previously demonstrated optical pre-amplified LIDAR with a perfect co-axial optical system[1]. For this we used a variable optical attenuator to remove internal reflection from the transmission and receiving lenses. However, the optical attenuator had an insertion loss of 6dB which reduced the sensitivity of the LIDAR. We re-designed the optical system such that it was semi-co-axial and removed the variable optical attenuator. As a result, we succeeded in scanning up to a range of 80 m. This small and highly sensitive measurement technology shows great potential for use in LIDAR.

We developed a LIDAR system with a sensor head as small as 22 cc, in spite of the inclusion of a scanning mechanism. This LIDAR system not only has a small body, but is also highly sensitive. Our LIDAR system is based on time-of-flight measurements, and it incorporates an optical fiber. The main feature of our system is the utilization of optical amplifiers for both the transmitter and the receiver, and the optical amplifiers enabled us to exceed the detection limit of thermal noise. In conventional LIDAR systems the detection limit is determined by thermal noise, because the avalanche photo-diodes (APD) and trans-impedance amplifiers (TIA) that they use detect the received signals directly. In the case of our LIDAR system, received signal is amplified by an optical fiber amplifier in front of the photo diode and the TIA. Therefore, our LIDAR system can boost the signal level before the weak incoming signal is depleted by thermal noise. There are conditions under which the noise figure for the combination of an optical fiber amplifier and a photo diode is superior to the noise figure for an avalanche photo diode. We optimized the gain of the optical fiber amplifier and TIA in our LIDAR system such that it is capable of detecting a single photon. As a result, the detection limit of our LIDAR system is determined by shot noise. This small and highly sensitive measurement technology shows great potential for use in LIDAR with an optical preamplifier.

Pseudo Random Noise (PN) coded laser radar can improve the target detection ability without the demand on high power laser. However, the reflected echoes are generally so weak that they are buried in the thermal noise of the receiver, which raises the problem of choosing an optimal threshold for correctly decoding them since the power of echoes varies from time to time, and the voltage of light generated electrical signal by photo diode (PD) is always positive. In this work, we firstly show the problem we are going to discuss. Then, a novel method basing on Inter Symbol Interference (ISI) is proposed for solving the problem. Next, numerical simulations and experiments are performed to validate the method. Finally, we discuss the obtained results theoretically.

X-ray powder diffraction data for a new calcium zirconium phosphate Ca7Zr(PO4)6are reported. The sample was prepared by heating mixtures of CaCO3, ZrO2, and NH4H2PO4in prescribed molar ratios at 1623 K. Powder diffraction data were collected with a laboratory X-ray source (Cu K?) for refinement of unit-cell parameters and intensity measurement of individual reflections. Crystallographic data were Ca7Zr(PO4)6, cubic, I-43d(No. 220), a=0.98338(1) nm, V=0.95097(3) nm3, Z=2, and Dx=3.29 Mg m?3. This compound is most probably isomorphous with eulytite.

The use of nanocolumn crystals is thought to be effective in producing a low-dislocation-density GaN layers. In this paper, we propose a metal--organic vapor phase epitaxial (MOVPE) growth method for producing uniform GaN nanocolumns using deep through-holes in a thick SiO2selective growth mask. A SiO2film with a thickness of 500 nm was deposited by sputtering on an AlN buffer layer/SiC substrate. A nanoimprinting technique was applied to produce dot openings. Then, dry etching with CF4gas was carried out to form deep through-holes in the SiO2film. In the second MOVPE growth, individual GaN nanocolumns coalesced into a planarized GaN layer, after thinning the SiO2mask to 100 nm. A cathode-luminescence image of the GaN layer on a GaN nanocolumn template shows a low dislocation density of $1.3\times 10^{8}$ cm-2, while that of a GaN layer directly grown on an AlN buffer layer shows a dislocation density of $9.4\times 10^{8}$ cm-2.

No relevant conflicts of interest to declare.

Natural killer (NK) cells have been proposed as a new source for immunotherapies in various malignancies. Previous studies have developed peripheral blood NK cells expansions or NK cells differentiation from cord blood cells. Expansion trial using IL-15 or dasatinib is not sufficient to obtain NK cells with high cytotoxicity. More recently, NK cells induction from human pluripotent stem cells (hPSCs), taking the advantage of their unlimited growth potential, has been reported. Although previous studies regarding hPSC-derived NK cells seems impressive and successful, most systems used bovine and human serum, which might result in the unstable yield and efficiency in the production of CD34+CD45+ HPCs and NK cells. To resolve those problems, we tried to induce functional NK cells from hPSCs under a completely chemically defined condition free from any non-autologous serum or stroma.