Adenosine triphosphate induces amorphous aggregation of amyloid β by increasing Aβ dynamics

アルツハイマー病に関係するアミロイドβ1分子の凝集動態を観察. 京都大学プレスリリース. 2024-04-23.Amyloid β (Aβ) aggregates into two distinct fibril and amorphous forms in the brains of patients with Alzheimer’s disease. Adenosine triphosphate (ATP) is a biological hydrotrope that causes Aβ to form amorphous aggregates and inhibit fibril formation at physiological concentrations. Based on diffracted X-ray blinking (DXB) analysis, the dynamics of Aβ significantly increased immediately after ATP was added compared to those in the absence and presence of ADP and AMP, and the effect diminished after 30 min as the aggregates formed. In the presence of ATP, the β-sheet content of Aβ gradually increased from the beginning, and in the absence of ATP, the content increased rapidly after 180 min incubation, as revealed by a time-dependent thioflavin T fluorescence assay. Images of an atomic force microscope revealed that ATP induces the formation of amorphous aggregates with an average diameter of less than 100 nm, preventing fibrillar formation during 4 days of incubation at 37℃. ATP may induce amorphous aggregation by increasing the dynamics of Aβ, and as a result, the other aggregation pathway is omitted. Our results also suggest that DXB analysis is a useful method to evaluate the inhibitory effect of fibrillar formation

Simultaneous estimation of slope angle and handling force when getting on and off a humanriding wheeled inverted pendulum vehicle.

Abstract-We are developing a human-riding wheeled inverted pendulum for use as a personal vehicle. To be practically usable, the vehicle requires a function that enables the rider to get on and off both safely and smoothly while on a slope of unknown angle. Concretely, for the convenience of the rider, the vehicle needs to be stabilized on an unknown slope without the rider aboard, both before the rider gets on it and after he/she gets off it. Moreover, the vehicle should be stabilized safely relative to the rider's handling force at a grip of the vehicle while getting on and off. We thus developed a method of estimating the handling force and the slope angle separately. In this paper, we report the method to estimate the handling force and the slope angle using a disturbance observer. We verified the validity of our proposed estimation method by computer simulations and experiments using a prototype of a humanriding wheeled inverted pendulum on an unknown slope

Electrocutaneous Communication in a Guide Dog Robot (MELDOG)

Two main problems to be solved in designing truly effective mobility aids for the blind are: 1) to determine what kinds and how many pieces of information are necessary and/or sufficient to mobilize humans, and 2) to establish the optimal coding and display method of the acquired information. If a robot is to be designed which can independently travel from one place to another, using a city map with specific landmarks stored in its memory and obstacle information gathered by the sensors on boarp the, robot, these pieces of information acquired and used by. the robot provide one solution to the first problem. In this paper, a guide dog robot (MELDOG) is described which approaches the first problem in this manner. MELDOG intends to enhance mobility aids for the blind by providing them with the functions of guide dogs, i.e., obedience in navigating its blind master, intelligent disobedience in detecting and avoiding obstacles in his/her path, and companionship in communicating between the master and the robot. For the second problem of displaying the information acquired, the electrocutaneous communication systems being developed, based on the fundamental experiments on electrocutaneous stimulation, are explained. These include constant pulse energy circuits which keep the perceived sensational magnitude constant despite the change of the skin impedance, and two-dimensional phantom sensations which reduce the number of the electrodes used

Utilization of Inertial Effect in Damping-based Posture Control of Mobile Manipulator

This paper presents the utilization of inertial effect in damping-based posture control of a mobile manipulator. As a measure for redundancy resolution of a mobile manipulator, an effective inertia at the end effector in the operational space is proposed and investigated. By changing the effective inertia property via null-motion, we can get the reduced inertial property of the mobile manipulator. The reduced effective inertia has a significant effect on reducing the impulse force in collision with environment. To find a posture satisfying both the reduced inertia and joint limit constraints, we propose a combined potential function method which can deal with multiple constraints. The proposed reduced inertia property algorithm is integrated into a damping controller to reduce the impulse force at collision and to regulate the contact force in mobile manipulation. 1

Multioperator Teleoperation of Multirobot Systems with Time Delay: Part II—Testbed Description

The Mechanical Engineering Laboratory (MEL)1 has been developing coordinated control technologies for multi-telerobot cooperation in a common environment remotely controlled from multiple operators physically distant from each other. Previously, we learned about how the transmission delay over the network deteriorates the performance of telerobots through simulations. To overcome the operator's delayed visual perception arising from network throughput limitations, we have suggested several coordinated control aids at the local operator site. The testbed facilitates experiments with physical robots for validation beyond simulation. This paper mainly discusses the details of the testbed and investigates the use of an online predictive simulator to assist the operator in coping with time delay over the network. Practically, a common data relay station is suggested to reduce the travel distance of the master data over the network and enable multirobot predictive simulation at one's master station. Operators control their master to get their telerobot to cooperate with the counterpart telerobot using the predictive simulator as well as video image feedback. Specifically, exploiting the audio-visual resources of the simulator, operators can detect a priori the possibility of collision and coordinate conflicting motions between telerobots. We have demonstrated an object rearrangement task by two telerobots and two operators via an ethernet LAN that is subject to simulated delays and evaluated the validity of the online predictive simulator in Multioperator-Multirobot (MOMR) tele-cooperation