The world has experienced dramatic urbanization in recent decades. However, we still lack information about the characteristics of urbanization in large cities throughout the world. After analyzing 841 large cities with built-up areas (BUAs) of over 100 km2 from 2001 to 2018, here we found an uneven distribution of urbanization at different economic levels. On average, large cities in the low-income and lower-middle-income countries had the highest urban population growth, and BUA expansion in the upper-middle-income countries was more than three times that of the high-income countries. Globally, more than 10% of BUAs in 325 large cities showed significant greening (P < 0.05) from 2001 to 2018. In particular, China accounted for 32% of greening BUAs in the 841 large cities, where about 108 million people lived. Our quantitative results provide information for future urban sustainable development, especially for rational urbanization of the developing world.

A pneumatically powered, reconfigurable omnidirectional soft robot based on caterpillar locomotion is described. The robot is composed of nine modules arranged as a three by three matrix and the length of this matrix is 154 mm. The robot propagates a traveling wave inspired by caterpillar locomotion, and it has all three degrees of freedom on a plane (X, Y, and rotation). The speed of the robot is about 18.5 m/h (two body lengths per minute) and it can rotate at a speed of 1.63°/s. The modules have neodymium-iron-boron (NdFeB) magnets embedded and can be easily replaced or combined into other configurations. Two different configurations are presented to demonstrate the possibilities of the modular structure: (1) by removing some modules, the omnidirectional robot can be reassembled into a form that can crawl in a pipe and (2) two omnidirectional robots can crawl close to each other and be assembled automatically into a bigger omnidirectional robot. Omnidirectional motion is important for soft robots to explore unstructured environments. The modular structure gives the soft robot the ability to cope with the challenges of different environments and tasks.

The results of our trial have shown that LBO laser en bloc resection is feasible, safe, and effective alternative for the treatment of primary non-muscle-invasive bladder tumors. Besides, it can provide intact specimen for the pathologic diagnosis. Lasers Surg. Med. 48:859-865, 2016. © 2016 Wiley Periodicals, Inc.

working. With the development of fabrication technology of soft robots, entirely flexible manipulator [9][10][11][12][13] and gripper [14][15][16][17][18] have been achieved. However, none of the existing soft actuators are appropriate for entirely flexible joint. Therefore, flexible twisting actuators with diverse functions and easy manufacture are needed to be designed.Pressurized air has been widely used as the main power source for soft actuators to achieve twisting or rotary motion, although an overpressure risk needs to be carefully considered in actuator design. [19][20][21][22][23][24][25] Lee et al., [19] Morin et al., [20] and Lazarus et al. [21] designed a range of twisting actuators powered by positive pressure with twisting angles of less than 62°. To improve performance, Connolly et al. [22] developed soft fluidic actuators reinforced by fibers, which can rotate up to 180°. They combined the actuators with different fiber angles in series to create a wormlike soft robot that could navigate through a pipe and insert prongs into holes. However, the actuator length needs to be increased to achieve larger twisting angles, which limits their application as flexible joints, since such structure requires a short length. Gorissen et al. [23] proposed a new soft actuator based on angled pneumatic balloon actuator arrays that can perform a large twisting angle of 71° without compromising an increase of actuator length. Four actuators were used to create a two degrees of freedom (DoFs) tilting mirror platform, which could turn at angles of ±25° and ± 29°. However, the actuator is not suitable for the development of soft robots due to its inherent sheet-like structure. A continuous rotary actuator driven by pressurized air was proposed by Gong et al. [24] who designed a pneumatic rotary actuator based on peristaltic motion of elastomeric materials. The actuator consisted of an inflatable stator that was paired with a rotor. A four-wheeled vehicle, which used a combination of the actuators, was prototyped and achieved a speed of 37 mm s −1 . The vehicle could travel over irregular terrains and survive high mechanical impact loads. The actuator was completely soft, but the cyclic fatigue behavior of the elastomeric bladders and delamination at the bonded interfaces were not clear and requires further investigation.Recently, pioneering studies employed the use of vacuum power to achieve torsional motion. [26][27][28] Yang et al. [26] exploited an elastomeric structure which contained a number of elastic beams and interconnected deformable cavities sealed within a Vacuum-powered soft pneumatic actuators (V-SPAs) are a promising enabling technology for a wide range of emerging applications, including artificial muscles, programmable locomotion, and flexible grippers. This is due to their flexible deformation, clean power supply, safe interaction with users, and high reliability compared with alternative actuators. A new vacuum-powered soft pneumatic twisting actuator (V-SPTA) is designed, which has a single seamless...