This study designed and fabricated a sensor chip that arranged 25 wells to droplet for antibody solution of 2 µL. We examined a reasonable mounting method for an enzyme-labeled antibody on the sensor chip. Further, we developed the degree of accumulation by image analysis. This study evaluated the correlation between image analysis method and existing absorbance method using a microplate reader.
This paper presents a heat-flow-type warmth sensor with sub-second response that discriminates materials for tactile sensing of robots. In previous study, the original sensor structure was proposed, and the material discrimination using a heat-flow peak in the heat-flow transitional phenomenon was demonstrated. In this study, to realize the material discrimination function as high response as human, the heat-flow-type warmth sensor with sub-second response was developed. Firstly, a thermal equivalent circuit of the sensor was proposed to simulate the transitional heat-flow characteristics. The simulation results showed that the response time of heat-flow peak is improved by reducing a heat capacity of the sensor and a thermal resistance of a surface material in the sensor. Secondly, miniaturized heat-flow-type warmth sensors downsized to 1/3.4 of previous one were fabricated according to the simulation results. The three miniaturized sensors were fabricated using three surface materials with different thermal resistances, and the experimental characteristics were compared to the simulation results. The tendencies of the experimental characteristics were agreement with those of the simulation results. Finally, the experimental results demonstrated the heat-flow-peak response times of 0.2 s with sufficient material discrimination function. Compared to the previous warmth sensor, the response time was improved 28 times.
This paper addresses a fundamental design guideline for rotational components of a micro-scale gas turbine engine considering an interaction between geometrical structure and aerodynamics. The rotational components of the micro-scale gas turbine engine may be subjected to the centrifugal stress due to high-speed rotation. The efficiency of each component is strongly controlled by geometrical clearance between rotational and stationary components, and heat transfer from the turbine to the compressor. Therefore, the elastic deformations due to the centrifugal stress and heat transfer have important role to determine the practical aerodynamic performance of the rotational components. A new sophisticated geometrical structure was introduced to the rotational components to control the elastic deformation and maintain the compressor efficiency that is necessary to hold the minimum requirement for the thermodynamic cycle.
We developed an optical-driven nanoneedle that is operated in aqueous solution by 2 focused laser beams. A nanoneedle tool consists of 2 micrometer-sized structures for optical trapping and a nanoneedle having 200 nm width and 20 μm length. Nanoneedle tools are fabricated with single UV lithography of SU-8 photoresist with highly scalable manner. We evaluated the conditions of the lithography processes: rinse, hardbake and PEB that determine the shape of the nanoneedles and recovery rate. We demonstrated the trapping of a nanoneedle tool to verify the manipulation of the position and the orientation. Nanoneedle tools have an advantage in the use of closed microchanells, which can lead to the applications including delivery and extraction of substances inside single cells and pinpoint molecular processing of biomolecules. In this paper, we report on the fabrication process of the nanoneedle tools and the demonstration of the manipulation.
Highly accurate isolation of circulating tumor cells (CTC) in the blood is essential for early detection of cancer. In particular, the dielectrophoretic device with a 3D structure can be expected to have separation accuracy, which cannot be obtained with conventional 2D shapes. In this study, an isolating leukemia-derived suspended Jurkat cell and fluorescent polystyrene particle, which are particles of uniform size, using a 3D microcylindrical electrodes are conducted. When the concentration of Jurkat cells was reduced to 1/100 of the concentration of polystyrene particles, Jurkat cells and polystyrene particles could be efficiently separated, and the collection efficiency at Outlet II, the outlet for the collection of target cells, was 100% and 2%, respectively. It was suggested that the proposed device may be able to separate cells of similar size with high accuracy.
This paper presents a new method which achieves accuracy like cuff-based BP (Blood pressure) measurement to improve the conventional cuff-less BP estimation method for a wrist-type single PPG sensor. The conventional method used the modified normalized pulse volume and the pulse rate for resistance and flow rate respectively to express BP. However, it is required to improve the performance in comparison with methods based on pulse wave velocity which involve elasticity rate relating to vascular pressure. The new method incorporates both resistance which is derived from relative velocity and peripheral arterial elasticity based on vascular function to elevate the accuracy of diastolic BP estimation. Systolic BP is also improved by the sum of estimated pulse pressure with resistance and the estimated diastolic BP value. The accuracy comparison between the conventional and proposal method was performed by cross validation for estimated BP values in 5 seconds each by using wrist-type PPG signals. It is found that the estimated SBP and DBP of the conventional method differed from the reference BP by 3.9 (mean absolute error) ±12 (standard deviation) mmHg and 4.7 ± 11 mmHg respectively. In the proposal method, the differences of estimated values are 2.5 ± 7.2 mmHg and 2.7 ± 7.8 mmHg. When compared to the AAMI requirement (5 ± 8 mmHg for both SBP and DBP estimation), the results suggest that the proposed method has great potential for a single PPG sensor device.
Collaborative robots, which work in the same places with humans, have recently been attracting a lot of attention. Proximity and tactile sensors are among the vital devices for collaborative robots to work safely. In this study, we proposed a proximity and contact sensor for a collaborative robot by combining a multiple time-of-flight (ToF) sensor and a self-capacitive sensor. ToF sensors can detect distance at a non-contact range, and they have a long measurement range with respect to the sensor vertical direction (Z-axis). However, the detection accuracy and X-Y axis detection range of ToF sensors are reduced at close ranges. Self-capacitive sensors can detect objects before and on contact, and they have high sensitivity at close ranges. However, the detection range of their Z-axis is small, and it is difficult for them to detect distance. In this study, we aimed at expanding the measurement range and reducing the blind spot area of collaborative robot sensors using multiple ToF sensors with the larger electrodes of self-capacitive sensors. Using the prototype sensor, it was possible to obtain efficient distance measurements with a range of 0-400 mm. The prototype sensors were placed on a robot arm, and they were able to detect object positions at a proximity range in addition to human contact. Additionally, the robot arm was controlled using measurement data. We believe that the proposed sensor can be used as a proximity and contact sensor for collaborative robots.