Colorectal cancer is a serious threat to human health. Colonoscopy is the most effective procedure for the inspection of colorectal cancer. However, traditional colonoscopy may cause pain, which can lead to the patient’s fear of colonoscopy. The use of active-motion colonoscopy robots is expected to replace traditional colonoscopy procedures for colorectal cancer screening, without causing pain to patients. This paper proposes an inchworm-like soft colonoscopy robot based on a rubber spring. The motion mechanism of the robot consists of two anchoring units and an elongation unit. The elongation unit of the robot is driven by 3 cables during contraction and by its inherent elasticity during extension. The balloon is selected as the anchoring mechanism of the robot. It has soft contact with the colon and will not damage the colon wall, which means no discomfort is caused. The elastic force test of the rubber spring shows that the elongation unit of the robot has sufficient restorative force to drive the robot to move forward and backward. The influence of the balloon’s expansion size on the dexterity of the robot head is analyzed, and the functions of the balloons are expounded. The balloon can not only assist the robot in its locomotion but also assist the robot to perform a better inspection. The robot can move successfully in a horizontal, straight, and inclined isolated pig colon, showing great clinical application potential.

Airflow sensor is a crucial component for monitoring environmental airflow conditions in many engineering fields, especially in the field of aerospace engineering. However, conventional airflow sensors have been suffering from issues such as complexity and bulk in structures, high cost in fabrication and maintenance, and low stability and durability. In this work, we developed a facile direct-writing method for fabricating a low-cost piezoresistive element aiming at high-performance airflow sensing, in which a commercial pen was utilized to drop solutions of single-walled carbon nanotubes onto tissue paper to form a piezoresistive sensing element. The encapsulated piezoresistive element was tested for electromechanical properties under two loading modes: one loading mode is the so-called pressure mode in which the piezoresistive element is pressed by a normal pressure, and another mode is the so-called bending mode in which the piezoresistive element is bended as a cantilever beam. Unlike many other developed airflow sensors among which the sensing elements are normally employed as cantilever beams for facing winds, we designed a fin structure to be incorporated with the piezoresistive element for airflow sensing; the main function of the fin is to face winds instead of the piezoresistive element, and subsequently transfer and enlarge the airflow pressure to the piezoresistive element for the normal pressure loading mode. With this design, the piezoresistive element can also be protected by avoiding experiencing large strains and direct contact with external airflows so that the stability and durability of the sensor can be maintained. Moreover, we experimentally found that the performance parameters of the airflow sensor could be effectively tuned by varying the size of the fin structure. When the fin sizes of the airflow sensors were 20 mm, 30 mm, and 40 mm, the detection limits and sensitivities of the fabricated airflow sensors were measured as 8.2 m/s, 6.2 m/s, 3.2 m/s, 0.0121 (m/s)⁻², 0.01657 (m/s)⁻², and 0.02264 (m/s)⁻², respectively. Therefore, the design of the fin structure could pave an easy way for adjusting the sensor performance without changing the sensor itself toward different application scenarios.

In this article, a class of p -Laplacian fractional differential equations with multiple derivative terms in the nonlinearity is studied. First, the Green’s function is derived and its key properties are analyzed, enabling us to construct a suitable cone for further analysis. Subsequently, using the Avery-Peterson fixed point theorem, the existence theorem of multiple positive solutions is established by examining the action of the Green’s function on the defined cone. The presence of multiple derivative terms in the nonlinearity introduces significant analytical challenges, particularly in proving the continuity and equicontinuity of the associated operator in the space C ⁱ [0, 1], which we have successfully overcome. Additionally, the nonlinearity exhibits singularity, and this issue is addressed by imposing appropriate conditions. To further explore solution existence, the Leray-Schauder nonlinear alternative and the Schauder fixed point theorem are employed to ensure the existence of nontrivial solutions. Moreover, under a generalized Lipschitz condition, the uniqueness of the solution is proved via the Banach fixed point theorem. Finally, two illustrative examples are provided to demonstrate the validity of the theoretical results presented.

As an irreplaceable element for obtaining airflow information in many engineering scenarios, airflow sensors have gained increasing attention across the fields of aerospace engineering, environmental engineering, sustainable energy exploitation, meteorology research, and so on. As one of the mainstream airflow sensing principles, piezoresistive airflow velocity sensors have experienced rapid growth over the years, while effective vector airflow sensors with the ability of detecting both airflow velocity and direction based on the piezoresistive principle are scarce. Here, on the basis of our developed piezoresistive airflow velocity sensors based on pressure loading mode, we design an array of these sensors and propose a corresponding explicit algorithm for simultaneous detection of airflow velocity and direction. This sensor array configuration enables an automatic recognition function of the quadrant of incoming airflow, which can significantly simplify the reverse calculation of airflow information compared with conventional vector airflow sensors. The experimental results demonstrate the decent performance of this sensor array for identifying both airflow velocity and direction. This study not only fills the gap between our developed airflow velocity sensor and the ability of detecting airflow direction but also presents a simple and universal array-based strategy for vector airflow sensing, which could be widely applied in airflow sensors based on other principles.

Images taken by an endoscope in single-port-access surgery are the most important information for directing surgeons to operate, so acquiring images taken at better position and a more desired perspective has profound significance for improving the efficiency and safety of surgery. The magnetically anchored laparoscope can help to realize this goal compared with the traditional laparoscope used in single-port-access surgery. In this paper, we propose the concept of applying ultrasonic motors in the magnetically anchored laparoscope. Two types of ultrasonic motors used for driving the laparoscope, namely a miniature traveling wave-rotating ultrasonic motor and a miniature traveling wave-tilt ultrasonic motor, are designed. The prototype of the magnetically anchored laparoscope using these two types of ultrasonic motors is fabricated and evaluated by experiments. The results show that the maximum output torque of the miniature traveling wave-rotating ultrasonic motor is 1.2 mN·m, and that of the miniature traveling wave-tilt ultrasonic motor is 1.4 mN·m, which is enough to actuate the magnetically anchored laparoscope. Additionally, it is proven that the two designed ultrasonic motors can be applied successfully in the laparoscope.