Soft robotics is an emerging field, since it offers distinct opportunities in areas where conventional rigid robots are not a feasible solution. However, due to the complex motions of soft robots and the stretchable nature of soft building materials, conventional electronic and fiber optic sensors cannot be used in soft robots, thus, hindering the soft robots’ ability to sense and respond to their surroundings. Fiber Bragg grating (FBG)-based sensors are very popular among various fiber optic sensors, but their stiff nature makes it challenging to be used in soft robotics. In this study, a soft robotic gripper with a sinusoidally embedded stretchable FBG-based fiber optic sensor is demonstrated. Unlike a straight FBG embedding configuration, this unique sinusoidal configuration prevents sensor dislocation, supports stretchability and improves sensitivity by seven times when compared to a straight configuration. Furthermore, the sinusoidally embedded FBG facilitates the detection of various movements and events occurring at the soft robotic gripper, such as (de)actuation, object holding and external perturbation. The combination of a soft robot and stretchable fiber optic sensor is a novel approach to enable a soft robot to sense and response to its surroundings, as well as to provide its operation status to the controller.

Photoinduced reactions of isatin and N-methyl-1,3,4-isoquinolinetrione with bicycloalkylidenes such as bicyclopropylidene, cyclopropylidenecyclobutane, cyclopropylidenecyclohexane and bicyclohexylidene were investigated. The reactions gave spirooxetanes as the major products derived from the [2 + 2] photocycloaddition pathway via 1,4-biradical recombination. Unusual products including the [4 + 2 + 2] cycloadducts, the oxoisochroman derivatives and other ring-rearranged products were derived from competitive pathways via 1,6-biradical recombination. The presence of oxygen in the reaction solution was found to be relevant to the distribution of different types of products. Mechanisms were proposed to rationalize the chemo- and regioselectivity in the photoreactions and the origin of the different types of products.

The increasing demands to enhance information security in data transmission, providing countermeasures against jamming in military applications, as well as boosting data capacity in mobile and satellite communication, have led to a critical need for high-speed frequency-hopping systems. Conventional electronics-based frequency-hopping systems suffer from low data rate, low hopping speed, and narrow hopping-frequency bandwidth. Unfortunately, those are important aspects to facilitate frequency-hopping in emerging microwave systems. The recent advancement of microwave photonics—the use of light to process microwave signals—provides promising solutions to tackle the challenges faced by electronic frequency-hopping systems. In this paper, the challenges of achieving real-time frequency-hopping systems are examined. The operation principles and results of various microwave photonics-enabled frequency-hopping systems are comprehensively discussed, which have wide hopping-frequency bandwidth and frequency-hopping speed from nanoseconds to tens of picoseconds. Lastly, a bio-inspired jamming-avoidance system that could potentially be used for adaptive frequency-hopping is also introduced.

No abstract

Background:In traditional Chinese medicine (TCM), raw and processed herbs are used to treat the different diseases. Fructus Arctii, the dried fruits of Arctium lappa l. (Compositae), is widely used in the TCM. Stir-frying is the most common processing method, which might modify the chemical compositions in Fructus Arctii.Materials and Methods:To test this hypothesis, we focused on analysis and identification of the main chemical constituents in raw and processed Fructus Arctii (PFA) by high-performance liquid chromatography/diode array detection-electrospray ionization-mass spectrometry.Results:The results indicated that there was less arctiin in stir-fried materials than in raw materials. however, there were higher levels of arctigenin in stir-fried materials than in raw materials.Conclusion:We suggest that arctiin reduced significantly following the thermal conversion of arctiin to arctigenin. In conclusion, this finding may shed some light on understanding the differences in the therapeutic values of raw versus PFA in TCM.

No abstract

No abstract

No abstract