Deciphering Vacancy Defect Evolution of 2D MoS2 for Reliable Transistors.

Two-dimensional (2D) MoS2 is an excellent candidate channel material for next-generation integrated circuit (IC) transistors. However, the reliability of MoS2 is of great concern due to the serious threat of vacancy defects, such as sulfur vacancies (VS). Evaluating the impact of vacancy defects on the service reliability of MoS2 transistors is crucial, but it has always been limited by the difficulty in systematically tracking and analyzing the changes and effects of vacancy defects in the service environment. Here, a simulated initiator is established for deciphering the evolution of vacancy defects in MoS2 and their influence on the reliability of transistors. The results indicate that VS below 1.3% are isolated by slow enrichment during initiation. Over 1.3% of VS tend to enrich in pairs and over 3.5% of the enriched VS easily evolve into nanopores. The enriched VS with electron doping in the channel cause the threshold voltage (Vth) negative drift approaching 6 V, while the expanded nanopores initiate the Vth roll-off and punch-through of transistors. Finally, sulfur steam deposition has been proposed to constrain VS enrichment, and reliable MoS2 transistors are constructed. Our research provides a new method for deciphering and identifying the impact of defects.

IMU Motion Capture Method with Adaptive Tremor Attenuation in Teleoperation Robot System.

Teleoperation robot systems can help humans perform tasks in unstructured environments. However, non-intuitive control interfaces using only a keyboard or joystick and physiological tremor reduce the performance of teleoperation. This paper presents an intuitive control interface based on the wearable device gForcePro+ armband. Two gForcePro+ armbands are worn at the centroid of the upper arm and forearm, respectively. Firstly, the kinematics model of the human arm is established, and the inertial measurement units (IMUs) are used to capture the position and orientation information of the end of the arm. Then, a regression model of angular transformation is developed for the phenomenon that the rotation axis of the torsion joint is not perfectly aligned with the limb segment during motion, which can be applied to different individuals. Finally, to attenuate the physiological tremor, a variable gain extended Kalman filter (EKF) fusing sEMG signals is developed. The described control interface shows good attitude estimation accuracy compared to the VICON optical capture system, with an average angular RMSE of 4.837° ± 1.433°. The performance of the described filtering method is tested using the xMate3 Pro robot, and the results show it can improve the tracking performance of the robot and reduce the tremor.

The Effects of a Passive Exoskeleton on Human Thermal Responses in Temperate and Cold Environments.

The exoskeleton as functional wearable equipment has been increasingly used in working environments. However, the effects of wearing an exoskeleton on human thermal responses are still unknown. In this study, 10 male package handlers were exposed to 10 °C (COLD) and 25 °C (TEMP) ambient temperatures while performing a 10 kg lifting task (LIFTING) and sedentary (REST) both with (EXO) and without the exoskeleton (WEXO). Thermal responses, including the metabolic rate and mean skin temperature (MST), were continuously measured. Thermal comfort, thermal sensation and sweat feeling were also recorded. For LIFTING, metabolic heat production is significant decrease with the exoskeleton support. The MST and thermal sensation significantly increase when wearing the exoskeleton, but thermal discomfort and sweating are only aggravated in TEMP. For REST, MST and thermal sensation are also increased by the exoskeleton, and there is no significant difference in the metabolic rate between EXO and WEXO. The thermal comfort is significantly improved by wearing the exoskeleton only in COLD. The results suggest that the passive exoskeleton increases the local clothing insulation, and the way of wearing reduces the "pumping effect", which makes a difference in the thermal response between COLD and TEMP. Designers need to develop appropriate usage strategies according to the operative temperature.

[Pharmacological mechanism of traditional sedative effect of alkaloids in Nelumbinis Plumula based on network pharmacology].

Nelumbinis Plumula has the traditional sedative effect,but its mechanism is unclear. In this study,the relationship between traditional sedative effect and hypnotic effect of Nelumbinis Plumula was taken as the starting point to study the hypnotic mechanism of the major medicinal components in Nelumbinis Plumula by the network pharmacology method. Targets of active Nelumbinis Plumula alkaloids were screened by Swiss Target Prediction server,TCMSP and BATMAN-TCM. Targets of hypnotic drugs approved by FDA were screened from Drug Bank,OMIM,TTD databases. The common targets were screened by GO and KEGG pathways. Cytoscape 3. 7. 1 software was used to construct the network of " active component-target-pathway-disease". The results of network analysis showed that 21 active compounds were associated with 44 targets and 28 pathways. Among them,21 compounds,35 targets and 15 pathways were predicted to be related to sedative hypnosis. Nelumbinis Plumula showed the hypnotic effect by acting on neuroactive ligand-receptor interaction pathway,regulation of actin cytoskeleton pathway,calcium signaling pathway,cholinergic synapse pathway.This study preliminarily revealed the potential active compounds and possible mechanisms of traditional sedative effect of Nelumbinis Plumula,which provided a theoretical basis for further experimental studies on medicinal materials and its mechanisms.

[Virtual screening of antithrombotic alkaloids from Houttuynia cordata].

Antithrombus is one of the effective methods to prevent and treat cardiovascular diseases. Based on the theory of traditional Chinese medicine,the author's previous research and relevant literature,it was found that the alkaloids in Houttuynia cordata has potential antithrombotic effect. However,the pharmacological substance basis and antithrombotic mechanism of H. cordata have not been clarified. In this study,molecular docking was used for virtual screening of antithrombotic alkaloids from H. cordata. Seventy alkaloids selected from H. cordata were screened in the docking ligand data-base with teen thrombosis targets with known crystal structures as the receptors. In addition,the small-molecule approved or to be approved drugs of targets from Drug Bank database were set as a positive reference with minimum score(S value) of each target's approved or to be approved drugs as threshold. The Dock module in Molecular Operating Environment(Version 2016) software was applied to screen the potential active compounds which their scores(S value) were lower than the minimum score of reference. At last the mechanism of antithrombotic effect was preliminarily revealed by compared the main active sites of the test alkaloids with original ligands and references. This study provided some useful information to development of antithrombus drugs.

Effects of copper ions on the characteristics of egg white gel induced by strong alkali.

This study investigated the effects of copper ions on egg white (EW) gel induced by strong alkali. Changes in gel characteristics were examined through texture profile analysis, scanning electron microscopy (SEM), and chemical methods. The value of gel strength reached its maximum when 0.1% copper ions was added. However, the lowest cohesiveness values were observed at 0.1%. The springiness of gel without copper ions was significantly greater than the gel with copper ions added. SEM results illustrated that the low concentration of copper ions contributes to a dense and uniform gel network, and an open matrix was formed at 0.4%. The free and total sulphhydryl group content in the egg white protein gel significantly decreased with the increased copper. The increase of copper ions left the contents of ionic and hydrogen bonds basically unchanged, hydrophobic interaction presented an increasing trend, and the disulfide bond exhibited a completely opposite change. The change of surface hydrophobicity proved that the main binding force of copper induced gel was hydrophobic interaction. However, copper ions had no effect on the protein component of the gels. Generally, a low level of copper ions facilitates protein-protein association, which is involved in the characteristics of gels. Instead, high ionic strength had a negative effect on gels induced by strong alkali.

Changes of microstructure characteristics and intermolecular interactions of preserved egg white gel during pickling.

Changes in gel microstructure characteristics and in intermolecular interactions of preserved egg whites during pickling were investigated. Spin-spin relaxation times of preserved egg whites significantly decreased in the first 8 days and remained unchanged after the 16th day. SEM images revealed a three-dimensional gel network, interwoven with a loose linear fibrous mesh structure. The protein gel mesh structure became more regular, smaller, and compacted with pickling time. Free sulfhydryl contents in the egg whites increased significantly, while total sulfhydryl contents dramatically decreased during pickling. The primary intermolecular forces in the preserved egg white gels were ionic and disulfide bonds. Secondary forces included hydrophobic interaction and relatively few hydrogen bonds. During the first 8 days, the proportion of ionic bonds sharply decreased, and that of disulfide bonds increased over the first 24 days.