Feasibility and safety of trans-biliary cryoablation: Preclinical evaluation of a novel flexible cryoprobe.

Cryoablation, as a well-characterized technology, has multifarious clinical applications in solid malignancy. However, trans-biliary cryoablation for malignant biliary obstruction has not been reported yet. Thus, this study aimed to determine the efficacy and safety of trans-biliary cryoablation with a novel CO2 gas-based flexible cryoprobe in standardized preclinical settings. For fresh porcine liver ex vivo, the freezing efficacy of cryoablation was evaluated by using fresh porcine liver. The real-time CO2 flow rate, freezing temperature and freezing range were examined and the frozen appearance was visualized. In vivo study, acute and chronical effects were investigated by using the models of canine bile duct. Histopathology and laboratory examination were performed. The lowest temperature that the electrode could deliver to the tissue was -60.7 °C. At 60s after freezing, the tissue temperature dropped to -22.6 °C and -4.3 °C at 0.1 and 0.2 cm from the electrode center, respectively. The frozen size was greater in liver tissue ex vivo than that in bile duct tissue in vivo. No biliary hemorrhage, perforation, stricture, obstruction, and adjacent organ injury were observed. With histopathologic examination, acute intercellular vacuoles were observed in the lamina propria adjacent to the lumen. Chronic changes, including uneven coagulative necrosis, fibro-proliferation, inflammatory infiltration and connective tissue thickening were observed in the lamina propria of the all biliary samples. The results demonstrated CO2 gas-based trans-biliary cryoablation is safe and efficacious. These findings may provide a potential new modality for primary malignant biliary obstruction and malignant obstruction within a biliary stent and contribute to cryoablation of clinical practice.

Design of a flexible surface/interlayer for packaging.

Impact resistance and thermal insulation are important factors to be considered in the fields of encapsulation and drug transportation. In this study, a classic circular sleeve structure is designed by integrating the multi-level surface topography of the sleeve and a hollow sandwich in the wall, which effectively improves the energy absorption efficiency and thermal insulation effect. With the increase of the levels of surface structure, the stiffness of the whole structure and the stress on the topmost structure decreases, which is conducive to protecting the structure. In addition, the thermal conduction efficiency can be limited and the heat preservation ability would be improved as the reduction of the contacting area of packages with internal objects is attributed to such specific topography. Moreover, the synergistic effect of the hollow sandwich further enhances the advantages of mechanics and heat insulation. Based on the findings of this study, this novel design has potential applications in fields such as thermal insulation, packaging, and pharmaceuticals.

Electronic whiskers for velocity sensing based on the liquid metal hysteresis effect.

The artificial biomimetic sensory hair as state-of-art electronics has drawn great attention from academic theorists of industrial production given its potential application in soft robotics, environmental exploration and health monitoring. However, it still remains a challenge to develop highly sensitive electronic sensory hair with fast response. In this study, a bio-inspired electronic whisker (e-whisker) with a hollow polymer shell and a liquid metal core was prepared by microinjection for airflow measurement and detection of obstacles. In addition, we illustrated the effect of liquid metal hysteresis on its distribution in microchannels on deformation. The difference in the deformed velocity between the selected fiber and EGaIn would result in a disturbance emerging in the liquid metal channel, which further causes a variation in resistance. Taking advantage of this phenomenon, the integrated fiber e-whisker can be employed to detect tiny airflow and disturbance. The experimental results indicate that the fiber sensor can detect the airflow velocity as low as 0.2 m s-1 within 0.1 s. The e-whisker can accurately monitor rainfall, human motion and object velocity. This work sheds light on the liquid metal viscosity-induced sensing mechanism and offers a novel strategy to fabricate high-performance velocity sensors.

Liquid Metal-Based Magnetorheological Fluid with a Large Magnetocaloric Effect.

Herein, liquid metal and Mn0.6Fe0.4NiGe0.54Si0.46 particles with a large magnetocaloric effect are adopted to prepare a novel magnetocaloric suspension named liquid metal-based magnetorheological fluid (LM2RF), which can well solve the problems of brittleness, low thermal conductivity, and poor machinability in classical magnetocaloric materials. The low melting point and high boiling point of liquid metal could significantly widen the operating temperature range of such a fluid. As a carrier, the high thermal conductivity, low viscosity, and large density of liquid metal display advantageous to heat transfer. The maximum loading fraction is 19.5 wt %, while LM2RF features the liquid state. A series of tests are conducted to investigate the alloying behavior in LM2RF. It is found that galinstan will react with Mn0.6Fe0.4NiGe0.54Si0.46 particles and form MnGa alloy. However, the reaction rate is very slow and the generated MnGa alloy is passivating. Consequently, the quantity of MnGa alloy is too sparse to affect the magnetocaloric performance of LM2RF. Overall, the LM2RF exhibits a large MCE at around room temperature with a lower magnetic hysteresis loss, and the transition temperature (Tm) remains constant in 60 days. This work demonstrates the outstanding performance of LM2RF and provides a promising alternative to MCE materials for practical magnetic refrigeration.