Insects are a constant source of inspiration for roboticists. Their compliant bodies allow them to squeeze through small openings and be highly resilient to impacts. However, making subgram autonomous soft robots untethered and capable of responding intelligently to the environment is a long-standing challenge. One obstacle is the low power density of soft actuators, leading to small robots unable to carry their sense and control electronics and a power supply. Dielectric elastomer actuators (DEAs), a class of electrostatic electroactive polymers, allow for kilohertz operation with high power density but require typically several kilovolts to reach full strain. The mass of kilovolt supplies has limited DEA robot speed and performance. In this work, we report low-voltage stacked DEAs (LVSDEAs) with an operating voltage below 450 volts and used them to propel an insect-sized (40 millimeters long) soft untethered and autonomous legged robot. The DEAnsect body, with three LVSDEAs to drive its three legs, weighs 190 milligrams and can carry a 950-milligram payload (five times its body weight). The unloaded DEAnsect moves at 30 millimeters/second and is very robust by virtue of its compliance. The sub–500-volt operation voltage enabled us to develop 780-milligram drive electronics, including optical sensors, a microcontroller, and a battery, for two channels to output 450 volts with frequencies up to 1 kilohertz. By integrating this flexible printed circuit board with the DEAnsect, we developed a subgram robot capable of autonomous navigation, independently following printed paths. This work paves the way for new generations of resilient soft and fast untethered robots.

Head-mounted displays for virtual reality (VR) and augmented reality (AR) allow users to see highly realistic virtual worlds. The wearable haptics that enable feeling and touching these virtual objects are typically bulky, tethered, and provide only low fidelity feedback. A particularly challenging type of wearable human-machine interface is feel-through haptics: ultra-thin wearables so soft as to be mechanically imperceptible when turned off, yet generating sufficient force when actuated to make virtual objects feel tangible, or to change the perceived texture of a physical object. Here, 18 µm thick soft dielectric elastomer actuators (DEA), directly applied on the skin, reports rich vibrotactile feedback generation from 1 Hz to 500 Hz. Users correctly identifies different frequency and sequence patterns with success rates from 73 to 97% for devices applied on their fingertips. An untethered version weighing only 1.3 grams allowed blindfolded users to correctly identify letters by "seeing" them through their fingers. The silicone-based DEA membrane is mechanically transparent, enabling wearable haptics for the many applications where hand dexterity is critical. The feel-through DEA can be placed in array format anywhere on the body.

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Transcervical curettage under laparoscopic guidance provides an alternative conservative treatment for interstitial pregnancy.

The inhibition of hepatitis B virus (HBV) capsid assembly is a novel strategy for the development of chronic hepatitis B (CHB) therapeutics. On the basis of the preclinical properties and clinical results of GLS4, we carried out further investigation to seek a better candidate compound with appropriate anti-HBV potency, reduced hERG activity, decreased CYP enzyme induction, and improved pharmacokinetic (PK) properties. To this end, we have successfully found that morpholine carboxyl analogues with comparable anti-HBV activities to that of GLS4 showed decreased hERG activities, but they displayed strong CYP3A4 induction in a concentration-dependent manner, except for morpholine propionic acid analogues. After several rounds of modification, compound 58 (HEC72702), which had an (R)-morpholine-2-propionic acid at the C6 position of its dihydropyrimidine core ring, was found to display no induction of the CYP1A2, CYP3A4, or CYP2B6 enzyme at the high concentration of 10 μM. In particular, it demonstrated a good systemic exposure and high oral bioavailability and achieved a viral-load reduction greater than 2 log in a hydrodynamic-injected (HDI) HBV mouse model and has now been selected for further development.