Abscopal Effect of Frozen Autograft Reconstruction Combined with an Immune Checkpoint Inhibitor Analyzed Using a Metastatic Bone Tumor Model

We evaluated the abscopal effect of re-implantation of liquid nitrogen-treated tumor-bearing bone grafts and the synergistic effect of anti-PD-1 (programmed death-1) therapy using a bone metastasis model, created by injecting MMT-060562 cells into the bilateral tibiae of 6–8-week-old female C3H mice. After 2 weeks, the lateral tumors were treated by excision, cryotreatment using liquid nitrogen, excision with anti-PD-1 treatment, and cryotreatment with anti-PD-1 treatment. Anti-mouse PD-1 4H2 was injected on days 1, 6, 12, and 18 post-treatment. The mice were euthanized after 3 weeks; the abscopal effect was evaluated by focusing on growth inhibition of the abscopal tumor. The re-implantation of frozen autografts significantly inhibited the growth of the remaining abscopal tumors. However, a more potent abscopal effect was observed in the anti-PD-1 antibody group. The number of CD8+ T cells infiltrating the abscopal tumor and tumor-specific interferon-γ (IFN-γ)-producing spleen cells increased in the liquid nitrogen-treated group compared with those in the excision group, with no significant difference. The number was significantly higher in the anti-PD-1 antibody-treated group than in the non-treated group. Overall, re-implantation of tumor-bearing frozen autograft has an abscopal effect on abscopal tumor growth, although re-implantation of liquid nitrogen-treated bone grafts did not induce a strong T-cell response or tumor-suppressive effect.     

Swarm robotic network using Lévy flight in target detection problem

One approach in swarm robotics is homogeneous system which is embedded with sensing, computing, mobile and communication components. In this study, a target detection problem, which is one of navigation problems, was employed. Once a robot detects a target, robots immediately communicate with a base station via intermediate relay robots due to the multi-hop transmission of wireless communication. Therefore, this control task is completed with connectivity of the network. In a target detection problem, we must improve the performance of exploration as well as connectivity of the network. This study investigates the performances of the two types of random walk algorithm in navigation while loosely ensuring connectivity of the robotic network based on our previous study.     

Emergency response to the nuclear accident at the Fukushima Daiichi Nuclear Power Plants using mobile rescue robots

On March 11, 2011, a massive earthquake (magnitude 9.0) and accompanying tsunami hit the Tohoku region of eastern Japan. Since then, the Fukushima Daiichi Nuclear Power Plants have been facing a crisis due to the loss of all power that resulted from the meltdown accidents. Three buildings housing nuclear reactors were seriously damaged from hydrogen explosions, and, in one building, the nuclear reactions became out of control. It was too dangerous for humans to enter the buildings to inspect the damage because radioactive materials were also being released. In response to this crisis, it was decided that mobile rescue robots would be used to carry out surveillance missions. The mobile rescue robots needed could not be delivered to the Tokyo Electric Power Company (TEPCO) until various technical issues were resolved. Those issues involved hardware reliability, communication functions, and the ability of the robots' electronic components to withstand radiation. Additional sensors and functionality that would enable the robots to respond effectively to the crisis were also needed. Available robots were therefore retrofitted for the disaster reponse missions. First, the radiation tolerance of the electronic componenets was checked by means of gamma ray irradiation tests, which were conducted using the facilities of the Japan Atomic Energy Agency (JAEA). The commercial electronic devices used in the original robot systems operated long enough (more than 100 h at a 10% safety margin) in the assumed environment (100 mGy/h). Next, the usability of wireless communication in the target environment was assessed. Such tests were not possible in the target environment itself, so they were performed at the Hamaoka Daiichi Nuclear Power Plants, which are similar to the target environment. As previously predicted, the test results indicated that robust wireless communication would not be possible in the reactor buildings. It was therefore determined that a wired communication device would need to be installed. After TEPCO's official urgent mission proposal was received, the team mounted additional devices to facilitate the installation of a water gauge in the basement of the reactor buildings to determine flooding levels. While these preparations were taking place, prospective robot operators from TEPCO trained in a laboratory environment. Finally, one of the robots was delivered to the Fukushima Daiichi Nuclear Power Plants on June 20, 2011, where it performed a number of important missions inside the buildings. In this paper, the requirements for the exploration mission in the Fukushima Daiichi Nuclear Power Plants are presented, the implementation is discussed, and the results of the mission are reported.     

Tracking a Sea Turtle by an AUV with a Multibeam Imaging Sonar: Toward Robotic Observation of Marine Life

International Journal of Control, Automation and Systems - This paper proposes a method for autonomous underwater vehicles to chase sea turtles without attaching any tag to them, toward efficient...     

Augmented reality-based block piling game with superimposed collapse prediction

Understanding what cannot be seen is difficult. Physical behavior can be explained on the basis of physical theories even if the behavior cannot be observed. Explanation of what is physically happening in the real world would become easy, however, if annotations were superimposed on the real objects. Herein, the authors demonstrate how an understanding of a physical event can be facilitated by overlapping a real-world situation with a simulation that predicts a future state. This idea is demonstrated in a game application in which a player stacks blocks into a pile until it collapses. In general, it is easy to estimate whether a block on the edge of a table will fall or not. However, it is more difficult to predict whether a stack of many blocks will collapse, and in what manner the stack will collapse. Even though previous research has demonstrated that the problem of how two-dimensionally stacked blocks collapse can be reduced to solving a sequence of convex quadratic programs, algorithms for convex quadratic programs require massive computational resources. Hence, the authors developed a fast and new algorithm based on a linear program. The proposed algorithm realizes real-time simulation based on physics that superimposes predicted collapse. The block that is predicted to fall is superimposed on the real block with a lit background projection. The system was evaluated in an experiment, and superimposed augmented reality annotation was observed to be efficient. The system was also demonstrated in game contests and received positive feedback and comments.     

High‐speed mobility on planetary surfaces: A technical review

Despite the success so far accomplished in the robotic exploration of the Moon and Mars, the constraints associated with newly proposed mission concepts manifest the need for a faster surface prospection. Increasing driving velocities is being considered as a potential solution to the requirements introduced by these missions. This review presents the benefits and foreseeable challenges of using faster locomotive solutions for space exploration. Information is provided regarding the set of missions that would benefit most from faster locomotive capabilities. Starting by understanding the theoretical framework governing the interaction of wheeled robots operating over loose, sandy terrains, we delve into the foundation of Bekker's classic terramechanic equations—the most frequently used method to predict mobile robots off‐road performance. We highlight its limitations and review the efforts that have been made to expand the range of application of these theories to dynamic wheel–soil interactions. We analyze the existing experimental evidence on the effects of increasing traveling velocities under earthbound, off‐road conditions. By paying special attention to previous experiences on the lunar surface, we outline the challenges that the combination of irregular terrains and a reduced‐gravity field may pose to a fast‐moving exploration rover. The principles, mathematical models, experimental evidence, and experiences presented in this review are meant to aid in the identification of poorly understood and insufficiently studied aspects regarding high‐speed extraterrestrial surface mobility.     

Mask design compensation for sloped sidewall structures fabricated by X-ray lithography

We have investigated and report in this paper the factors influencing the deformation caused by the dependence between the absorbed X-ray energy on the resist and the shape of the absorber on the X-ray mask. Based on the measurement of errors that occurred during the transferring process between the 2-D shape of mask pattern and the resulting wall of the fabricated 3-D structure, we have developed newly useful graphical data on the absorbed X-ray energy, dosage, and shape of a microstructure. As a result, it is being reported as a method for compensation for the deformed shape after the fabrication of a quadruplets-microneedle. We have considered a number of factors affecting the deformation and finally realized that the effect of a dose–depth nonlinear curve is the most possible cause. Without the compensation of the mask design, we could observe the deformed shapes of the sloped sidewall on the exposed structures. Polymethylmethacrylate microneedle structures fabricated by X-ray lithography with an additional plane-pattern to cross-section transfers technique are directly influenced by the absorber on the X-ray mask pattern. The sidewall of the microneedle was improved by changing the mask pattern from a double right-triangular pattern to a double semi-circular pattern, modeled by comparing the results from a mask-pattern and the actual structure.     

Molecular valve consisting of poly(acrylic acid) gel

A molecular valve, consisting of poly(acrylic acid) gel-coated Au mesh, was developed based on volume change of the gel in response to cation concentration. The valve closed when concentration of cations such as H⁺, Na⁺, K⁺, Ca²⁺, Cu²⁺, or Al³⁺ was low, whereas opened upon increase in its concentration. The valve re-closed when water was flowed. The concentration where the valve opens was found to increase in the order of Al³⁺, Ca²⁺, and Na⁺ (2 × 10⁻⁴, 5 × 10⁻⁴, and 6 × 10⁻³ M, respectively). The response to Cu²⁺ ion showed similar behaviour, but the opening concentration was ca. 2 × 10⁻⁴ M, which is lower than that of Ca²⁺ ion. The valve appeared to close over the pH range from 3 to 12, whereas to open below and above it. The fastest response time to open the valve (less than 1 min) was obtained for a solution of pH 1–2. The valve showed repeatability at least 25 cycles upon successive loading of a solution of pH 2 and water. Effects of anions and pressure were also studied.     

Positioning device for outdoor mobile robots using optical sensors and lasers

We propose a novel method for positioning a mobile robot in an outdoor environment using lasers and optical sensors. Position estimation via a noncontact optical method is useful because the information from the wheel odometer and the global positioning system in a mobile robot is unreliable in some situations. Contact optical sensors such as computer mouse are designed to be in contact with a surface and do not function well in strong ambient light conditions. To mitigate the challenges of an outdoor environment, we developed an optical device with a bandpass filter and a pipe to restrict solar light and to detect translation. The use of two devices enables sensing of the mobile robot’s position, including posture. Furthermore, employing a collimated laser beam allows measurements against a surface to be invariable with the distance to the surface. In this paper, we describe motion estimation, device configurations, and several tests for performance evaluation. We also present the experimental positioning results from a vehicle equipped with our optical device on an outdoor path. Finally, we discuss an improvement in postural accuracy by combining an optical device with precise gyroscopes.