Control of a Quadruped Robot with Bionic Springy Legs in Trotting Gait

Legged robots have better performance on discontinuous terrain than that of wheeled robots. However, the dynamic trotting and balance control of a quadruped robot is still a challenging problem, especially when the robot has multi-joint legs. This paper presents a three-dimensional model of a quadruped robot which has 6 Degrees of Freedom （DOF） on torso and 5 DOF on each leg. On the basis of the Spring-Loaded Inverted Pendulum （SLIP） model, body control algorithm is discussed in the first place to figure out how legs work in 3D trotting. Then, motivated by the principle of joint function separation and introducing certain biological characteristics, two joint coordination approaches are developed to produce the trot and provide balance. The robot reaches the highest speed of 2.0 m.s-1, and keeps balance under 250 Kg.m.s-1 lateral disturbance in the simulations. The effectiveness of these approaches is also verified on a prototype robot which runs to 0.83 m.s-1 on the treadmill, The simulations and experiments show that legged robots have good biological properties, such as the ground reaction force, and spring-like leg behavior.     

Design and Kinematic Analysis of a Novel Humanoid Robot Eye Using Pneumatic Artificial Muscles

This paper proposed a novel humanoid robot eye, which is driven by six Pneumatic Artificial Muscles （PAMs） and rotates with 3 Degree of Freedom （DOF）. The design of the mechanism and motion type of the robot eye are inspired by that of human eyes. The model of humanoid robot eye is established as a parallel mechanism, and the inverse-kinematic problem of this flexible tendons driving parallel system is solved by the analytical geometry method. As an extension, the simulation result for saccadic movement is presented under three conditions. The design and kinematic analysis of the prototype could be a sig- nificant step towards the goal of building an autonomous humanoid robot eye with the movement and especially the visual functions similar to that of human.     

Dynamic Modeling and Experiment of a Fish Robot with a Flexible Tail Fin

This paper presents the dynamic modeling of a flexible tail for a robotic fish. For this purpose firstly, the flexible tail was simplified as a slewing beam actuated by a driving moment. The governing equation of the flexible tail was derived by using the Euler-Bernoulli theory. In this equation, the resistive forces were estimated as a term analogous to viscous damping. Then, the modal analysis method was applied in order to derive an analytical solution of the governing equation, by which the relationship between the driving moment and the lateral movement of the flexible tail was described. Finally, simulations and experiments were carried out and the results were compared to verify the accuracy of the dynamic model. It was proved that the dynamic model of a fish robot with a flexible tail fin well explains the real behavior of robotic fish in underwater environment.     

Toward Fast and Efficient Mobility in Aquatic Environment: A Robot with Compliant Swimming Appendages Inspired by a Water Beetle

Water beetles are proficient drag-powered swimmers,with oar-like legs.Inspired by this mechamsm,here we propose a miniature robot,with mobility provided by a pair of legs with swimming appendages.The robot has optimized linkage structure to maximize the stroke angle,which is actuated by a single DC motor with a series of gears and a spring.A simplified swimming appendage model is proposed to calculate the deflection due to the applied drag force,and is compared with simulated data using COMSOL Multiphysics.Also,the swimming appendages are optimized by considering their locations on the legs using two fitness functions,and six different configurations are selected.We investigate the performance of the robot with various types of appendage using a high-speed camera,and motion capture cameras.The robot with the proposed configuration exhibits fast and efficient movement compared with other robots.In addition,the locomotion of the robot is analyzed by considering its dynamics,and compared with that of a water boatman (Corixidae).     

输尿管软镜与超微通道经皮肾镜碎石术治疗直径<2cm肾结石的对照分析研究

摘要 目的：对比分析输尿管软镜碎石术与超微通道经皮肾镜碎石术治疗直径<2 cm的肾结石的临床应用效果。方法：选取2017年7月～2019年11月间直径<2 cm肾结石患者200例作为研究对象,随机选择其中的100例患者采用输尿管软镜钬激光碎石术进行治疗(FURS组),另外的100例患者采用超微通道经皮肾镜钬激光碎石术进行治疗(UMP组),比较观察两组患者的手术相关指标,其中包括手术时间、术中出血量、清石率,以及患者术后下床活动时间、术后住院天数等指标的差异,同时记录两组患者术后并发症的情况。结果：两组手术均成功完成,未出现严重出血及邻近器官损伤等并发症,在清石率方面,两组均有较高水平,无统计学差异（98% vs 97%,P＞0.05）;在手术并发症发生率方面,差异无统计学意义 (7% vs 8%,P＞0.05);术中血红蛋白下降水平FURS组少于UMP组（6.82±2.27 vs 16.75±4.92,P＜0.01）;FURS组较UMP组术后下床活动时间（7.53±2.24 vs 15.46±2.61,P＜0.01）以及住院天数（3.46±1.69 vs 6.15±1.27,P<0.01）更少,差异有统计学意义。结论：输尿管软镜钬激光碎石术与微通道经皮肾镜钬激光碎石术都可以成为直径<2 cm肾结石的有效治疗方法,但输尿管软镜钬激光碎石术的患者术中出血少,住院时间短,更为安全,疗效确切,更加具有微创优势,值得优先考虑。     

Study on the binding mode of a pyrrolotriazin derivative with JAK2 by docking and MD simulation

The pyrrolotriazin derivative 2-(4-(4-((7-(3-(N-methylmethylsulfonamido)phenyl)pyrrolo [2,1-f][1,2,4]triazin-2-yl)amino)phenyl)piperidin-1-yl)acetamide (PPA) is a potential Janus kinase 2 (JAK2) inhibitor. The binding mode between PPA and JAK2 was investigated by using a combined method of docking, molecular dynamics (MD) simulation and binding free-energy calculation. The docking calculations preliminarily indicated that there were two possible binding modes 1 and 2; MD simulations and binding free-energy calculations identified that binding mode 1 was more stable and favourable, with the lower MM-PBSA binding free energy of ?34.00?±?0.17?kcal/mol. Moreover, some valuable binding information is revealed as follows: the inhibitor PPA is suitably located at the ATP-binding site of JAK2 and the hydrophobic interaction plays an essential role. PPA not only interacts with residues Leu855, Val863, Ala880, Tyr931, Leu932 and Leu983 via hydrophobic interaction but also interacts with Ser936 and Asp994 by hydrogen bonds. These two factors are advantageous for PPA to strongly bind to JAK2. These results help to understand the action mechanisms and designing new compounds with a higher affinity to JAK2.     

Design and synthesis of new antitumor agents with the 1,7-epoxycyclononane framework. Study of their anticancer action mechanism by a model compound

This article describes the design, synthesis and biological evaluation of a new family of antitumor agents having the 1,7-epoxycyclononane framework. We have developed a versatile synthetic methodology that allows the preparation of a chemical library with structural diversity and in good yield. The synthetic methodology has been scaled up to the multigram level and can be developed in an enantioselective fashion. The study in vitro of a model compound, in front of the cancer cell lines HL-60 and MCF-7, showed a growth inhibitory effect better than that of cisplatin. The observation of cancer cells by fluorescence microscopy showed the presence of apoptotic bodies and a degradation of microtubules. The study of cell cycle and mechanism of death of cancer cells by flow cytometry indicates that the cell cycle arrested at the G₀/G₁ phase and that the cells died by apoptosis preferably over necrosis. A high percentage of apoptotic cells at the subG₀/G₁ level was observed. This indicates that our model compound does not behave as an antimitotic agent like nocodazole, used as a reference, which arrests the cell cycle at G₂/M phase. The interaction of anticancer agents with DNA molecules was evaluated by atomic force microscopy, circular dichroism and electrophoresis on agarose gel. The results indicate that the model compound has not DNA as a target molecule. The in silico study of the model compound showed a potential good oral bioavailability.