Analysis of an Imported Subgenotype C2 Strain of Human Enterovirus 71 in Beijing, China, 2015

Background: Subgenotype C4 of enterovirus 71 (EV71) is the predominant agent of Hand Foot and Mouth disease (HFMD) circulating in the mainland of China. For the first time, a subgenotype C2 of EV71 named SY30-2 was isolated from a HFMD case in Beijing, China. Since it is uncertain whether antibodies raised against subgenotype C4 of EV71 can protect C2 EV71, it is important to monitor and check the presence of cross-reactive antibodies against new EV71 subgenotypes. To find out the causes for the different NtAb, this study is to investigate the relationships between amino acid residue variations and cross-reactive antibodies against EV71 subgenotypes C2 and C4.Methods: Nucleotide and amino acid sequences from full-length genome sequence of SY30-2 were compared to EV71 reference strains. A microneutralization test was used to detect neutralizing antibody (NTAb) in the sera of subgenotype C4 of EV71 infected cases against SY30-2 and FY17 (a C4 isolate). The 3D structure of the viral capsid protein of SY30-2 was constructed.Results: Genome sequence and similarity plot analyses showed that SY30-2 shared the highest identity with subgenotype C2 of EV71 strains in every fragment of the genome. While the microneutralization test result showed that children infected with subgenotype C4 of EV71 had higher NTAb titers against FY17 than SY30-2 (p < 0.001). The amino acid sequence comparison revealed that four amino acid residues VP1-22, VP1-31, VP1-249 and VP3-93 were highly conserved in subgenotype C4 of EV71 compared with the corresponding amino acid residues on subgenotype C2 of EV71 (p < 0.05). Furthermore, the 3D-structure of viral capsid protein showed that VP1-22, VP1-31 and VP3-93 were located on the surface of virion.Conclusion: This is the first report of an EV71 subgenotype C2 isolated from HFMD in Beijing, China. Only a few antigenic variations on subgenotype C2 of EV71 could have led to a great decrease in NTAb titer. Thus, imported new genotypes and subgenotypes of EV71 should be closely monitored. The efficacy of available vaccines against new viruses should be evaluated as well

The Development of a Soft Robot Hand with Pin-Array Structure

This paper proposes a soft robot hand with pin-array structure and self-adaptive function, CTSA-II hand, where CTSA is the Cluster tube self-adaption. The CTSA-II hand is designed with a quite concise structure and consists of bases, a pin array, a spring array, and a membrane. When the CTSA-II hand grasps an object, the pins will slide along the trajectory to conform to the profile of the object under the reaction force applied by the object, and thus the outer membrane will form a specific shape, and then the vacuum drives the CTSA-II hand to grasp the object. Theoretical analysis shows that the CTSA-II hand can generate enough grasping force and get good stability. Moreover, the optimization of its structure is achieved by studying the effects of specific parameters. The capture experimental results of the prototype show that the CTSA-II hand can realize self-adaptive grasping of different sizes and shapes with a high degree of fit and a high success rate. A series of research experiments show the influence of various factors on the grasping force, which verifies the results of the theoretical analysis with the CTSA-II hand. Compared to the traditional robot hand, the CTSA-II hand has good crawl performance, concise structure, small volume, and easy assembly

VGS Hand: A Novel Hybrid Grasping Modes Robot Hand with Variable Geometrical Structure

Robot hand is the device used for robots to interact with the environments, it has many potential applications. Traditional robot hands cannot translate their finger end along a straight line, which makes them not suitable for grasping thin objects on a flat surface. In order to overcome the bottleneck of traditional hands and enlarge the application possibility of robot hands, this paper develops a novel hybrid grasping modes hand with the variable geometrical structure (called VGS hand). The hand consists of 4-DOF (degree of freedom), two actuators and two fingers. It can perform both linear-parallel and self-adaptive grasping modes. Kinematics, dynamics, and contact forces analysis are conducted to provide a theoretical reference for the design. A prototype was manufactured for grasping experiments; the results of the experiments indicate that the hand has a good grasping performance and can meet different application requirements

A Worm-Inspired Robot Flexibly Steering on Horizontal and Vertical Surfaces

Based on the motion principle of bionic earthworms, we designed and fabricated a novel crawling robot driven by pneumatic power. Its structure is divided into four segments, and its motion process is periodic with high stability. Due to the pneumatic suction cups mounted on its feet, it is able to crawl on smooth horizontal, inclined, or vertical walls. On this basis, we designed a novel underactuated steering mechanism. Through the tendons on both sides and the springs installed on the side of the robot, we accurately controlled the steering motion of the robot. We analyzed the steering process in detail, calculated the influence of external parameters on the steering process of the robot, and simulated the trajectory of the robot in the steering process. The experimental results validated our analysis. In addition, we calculate the maximum thrust that each segment of the robot can provide, and determine the maximum load that the robot can bear during climbing motions

Multi-Mode Compound Grasping Robot Finger Driven by Linkage

The current underactuated robot hands use a single actuator to drive multiple degrees of freedom, enabling them to perform grasping functions. This paper design a multi-mode compound grasping robot finger driven by linkage, called MCG hand. The MCG hand includes a base, two motors, three phalanx, multiple shafts, two motors, two driving wheels, four linkages, three springs, and two limit blocks. This unique design allows the MCG finger to perform various grasping modes, such as parallel, coupling, middle, and distal phalanx self-adaptive, proximal, and distal gesture-changeable modes, as well as their combinations. The device can independently control the rotation of the proximal phalanx and the distal joint and realize the parallel pinching action of the distal phalanx. It can also realize the coupling function of the proximal and distal phalanx. It has automatic adaptability to objects of different shapes and sizes. Furthermore, the MCG finger provides enveloping grasping with multiple contact points, resulting in a more stable grip. The easy switching between modes through simple control, along with its wide application range and low manufacturing and maintenance costs, make the MCG hand a versatile solution for various applications

A Robot Gripper with Differential and Hoecken Linkages for Straight Parallel Pinch and Self-Adaptive Grasp

Parallel pinch is an important grasp method. The end phalanx of the traditional parallel pinch and self-adaptive gripper moves in an arc trajectory, which requires the auxiliary lifting motion of the industrial manipulator, which is inconvenient to use. To solve this problem, a novel robot finger is designed and implemented—Hoecken’s finger. In this finger, the Hoecken linkage mechanism is used to realize the straight-line trajectory of the end joint, the differential mechanism set on the surface of the phalanxes is used to realize the shape self-adaptation of the first and second phalanxes, and the parallel four-bar linkage in series is used to realize the attitude keeping, thus comprehensively realizing the underactuated gripper driven by a single motor. After analyzing the grasp force and grasp motion of Hoecken’s fingers, the optimized parameters are obtained, and the Hoecken’s gripper is developed. The experimental results show that the gripper can realize the self-adaptive grasp function of straight parallel pinch, the grasp is stable, and the grasp range is large. It can be applied to more scenes that need to grasp objects

A Flexible Arrayed Eddy Current Sensor for Inspection of Hollow Axle Inner Surfaces

A reliable and accurate inspection of the hollow axle inner surface is important for the safe operation of high-speed trains. In order to improve the reliability of the inspection, a flexible arrayed eddy current sensor for non-destructive testing of the hollow axle inner surface was designed, fabricated and characterized. The sensor, consisting of two excitation traces and 28 sensing traces, was developed by using the flexible printed circuit board (FPCB) technique to conform the geometric features of the inner surfaces of the hollow axles. The main innovative aspect of the sensor was the new arrangement of excitation/sensing traces to achieve a differential configuration. Finite element model was established to analyze sensor responses and to determine the optimal excitation frequency. Experimental validations were conducted on a specimen with several artificial defects. Results from experiments and simulations were consistent with each other, with the maximum relative error less than 4%. Both results proved that the sensor was capable of detecting longitudinal and transverse defects with the depth of 0.5 mm under the optimal excitation frequency of 0.9 MHz