A Multiphase Semistatic Training Method for Swarm Confrontation Using Multiagent Deep Reinforcement Learning.

In this paper, we propose a multiphase semistatic training method for swarm confrontation using multi-agent deep reinforcement learning. In particular, we build a swarm confrontation game, the 3V3 tank fight, based on the Unity platform and train the agents by a MDRL algorithm called MA-POCA, coming with the ML-Agent toolkit. By multiphase learning, we split the traditional single training phase into multiple consecutive training phases, where the performance level of the strong team for each phase increases in an incremental way. On the other hand, by semistatic learning, the strong team in all phases will stop learning when fighting against the weak team, which reduces the possibility that the weak team keeps being defeated and learns nothing at all. Comprehensive experiments prove that, in contrast to the traditional single-phase training method, the multiphase semistatic training method proposed in this paper can significantly increase the training efficiency, shedding lights on how the weak could learn from the strong with less time and computational cost.

Controllable synthesis of lignin nanoparticles with antibacterial activity and analysis of its antibacterial mechanism.

As a kind of polyphenol substance, lignin is considered to have good biological activity and certain antibacterial properties. However, it is difficult to be applied because of its uneven molecular weight and difficulty in separation. In this study, by way of fractionation and antisolvent, we obtained lignin fractions with different molecular weight. Moreover, we increased the content of active functional groups and regulated microstructure of lignin, thereby increased lignin's antibacterial property. The classification of chemical components and the control of particle morphology also provided convenience for the exploration of lignin's antibacterial mechanism. The results showed that acetone with high hydrogen bonding ability could collect lignin with different molecular weights and increase the content of phenolic hydroxyl groups, up to 31.2 %. By adjusting the ratio of water/solvent (v/v) and stirring rate during the process of antisolvent, lignin nanoparticles (sphere 40-300 nm) with regular shape and uniform size can be obtained. Through observing the distribution of lignin nanoparticles in vivo and in vitro after co-incubation for different time, it could be found that lignin nanoparticles firstly damage structural integrity of bacterial cells externally, and then are swallowed into cells to affect their protein synthesis, which constitutes a dynamic antibacterial process.

Silver Nanoparticle-Embedded Conductive Hydrogels for Electrochemical Sensing of Hydroquinone.

In this work, a conductive hydrogel was successfully synthesized, taking advantage of the high number density of active amino and hydroxyl groups in carboxymethyl chitosan and sodium carboxymethyl cellulose. These biopolymers were effectively coupled via hydrogen bonding with the nitrogen atoms of the heterocyclic rings of conductive polypyrrole. The inclusion of another biobased polymer, sodium lignosulfonate (LS), was effective to achieve highly efficient adsorption and in-situ reduction of silver ions, leading to silver nanoparticles that were embedded in the hydrogel network and used to further improve the electro-catalytic efficiency of the system. Doping of the system in the pre-gelled state led to hydrogels that could be easily attached to the electrodes. The as-prepared silver nanoparticle-embedded conductive hydrogel electrode exhibited excellent electro-catalytic activity towards hydroquinone (HQ) present in a buffer solution. At the optimum conditions, the oxidation current density peak of HQ was linear over the 0.1-100 µM concentration range, with a detection limit as low as 0.12 µM (signal-to-noise of 3). The relative standard deviation of the anodic peak current intensity was 1.37% for eight different electrodes. After one week of storage in a 0.1 M Tris-HCl buffer solution at 4 °C, the anodic peak current intensity was 93.4% of the initial current intensity. In addition, this sensor showed no interference activity, while the addition of 30 µM CC, RS, or 1 mM of different inorganic ions does not have a significant impact on the test results, enabling HQ quantification in actual water samples.

Design of AgNPs doped chitosan/sodium lignin sulfonate/polypyrrole films with antibacterial and endotoxin adsorption functions.

There is an urgent need to develop materials to prevent bacterial infection and the deleterious effects of endotoxins. In this study, we introduce a one-step electrodeposition method to prepare films composed of chitosan/Ag/polypyrrole and layer-by-layer self-assembly to introduce lignin sulphonate (LS) to obtain chitosan/Ag/polypyrrole/LS films. Antibacterial effects against both E. coli and S. aureus are shown by bacterial growth profiles and observation of bacteriostatic zones. Meanwhile, the addition of self-assembled LS improved the antibacterial effect of the film. For E. coli, the inhibition zone diameter was 0.93 cm, while for S. aureus, the inhibition zone diameter was 0.72 cm. Rapid and efficient endotoxin adsorption effects were shown whereby the electrostatic interactions between chitosan and endotoxin molecules played a major role. After adsorption for 1 h, in initial concentration of 1 EU/mL endotoxin solution, the adsorption efficiency could reach up to 85 %, while in initial concentration of 5 EU/mL endotoxin solution, the adsorption efficiency could reach up to 87.6 %. The results suggest chitosan/Ag/polypyrrole/LS films for their capability as a new type of antibacterial film with intrinsic endotoxin adsorption activity.

Electrochemical sensing of Staphylococcus aureus based on conductive anti-fouling interface.

A system for the rapid and ultra-sensitive detection of Staphylococcus aureus (S. aureus), a prevalent foodborne pathogen is introduced. Limitations of typical electrochemical sensing, often subjected to interference from non-specific protein adsorption are addressed. A dual-aptamer-based sandwich immunobiosensor is shown for its benefits regarding specificity and anti-fouling capacity, endowed by a sulfonated polyaniline layer combined with signal amplification via highly conductive gold nanoparticles. EIS spectra (Nyquist plots) were recorded at pH 7.4 PBS containing 5 mM Fe(CN)63-/Fe(CN)64-, in order to verify the possibility of the electrochemical sensing for detection of S. aureus. Results demonstrated that the constructed immunobiosensor presents an extended detection range (1 × 101 to 1 × 105 CFU/mL) and detection limit as low as 2 CFU/mL. The resistance values of the immunobiosensor developed  maintain at a stable value during 2 weeks.  Besides, the specificity of the system is highlighted by testing raw milk, and the results of which demonstrate the excellent prospects of the system for monitoring foodborne pathogens.

Electrochemical sensing technology for liquid biopsy of circulating tumor cells-a review.

In recent years, a lot of new detection techniques for circulating tumor cells (CTCs) have been developed. Among them, electrochemical sensing technology has gradually developed because of its advantages of good selectivity, high sensitivity, low cost and rapid detection. Especially in the latest decade, the field of electrochemical biosensing has witnessed great progress, thanks to the merging of biosensing research area with nanotechnology, immunotechnology, nucleic acid technology, and microfluidic technology. In this review, the recent progress for the detection of CTCs according to the principle of detection was summarized and how they can contribute to the enhanced performance of such biosensors was explained. The latest electrode construction strategies such as rolling circle amplification reaction, DNA walker and microfluidic technology and their advantages were also introduced emphatically. Moreover, the main reasonswhy the existing biosensors have not been widely used clinically and the next research points were clearly put forward.

Recyclable deep eutectic solvent coupling sodium hydroxide post-treatment for boosting woody/herbaceous biomass conversion at mild condition.

A novel recyclable deep eutectic solvent (DES) consisting of p-toluene sulfonic acid (p-TsOH) and choline chloride (ChCl) was developed for efficient woody poplar sawdust (PL) and herbaceous miscanthus (MC) conversion at mild condition. The extraction of leftover lignin on the surface of DES pretreated residues using NaOH solution at room temperature greatly improved the enzymatic hydrolysis efficiency. Near complete cellulose conversion of PL and MC residues were obtained with a degree of delignification and xylan removal over 90% at 100 °C within 40 min. The strong correlations between xylan (R2 = 0.95) and lignin (R2 = 0.82) removal with cellulose conversion were observed in MC as well as positive correlations (R2 > 0.77) in PL. The results demonstrated that the DES system coupling NaOH post-treatment was a promising method to achieve an economically feasible biomass conversion process, which was effective for both woody PL residues and herbaceous MC.