Enhancing the functional characteristics of soy protein isolate via cross-linking catalyzed by Bacillus subtilis transglutaminase.

BACKGROUND: Although Streptomyces mobaraense transglutaminase (MTG) has been extensively applied to enhance the functional characteristics of soy protein isolate (SPI) through cross-linking, various transglutaminases (TGs) in nature may provide more choice in the food industry. Previous research reported that TG derived from Bacillus subtilis (BTG) exhibited better pH stability and thermostability than MTG. RESULTS: An attempt was made to study the influence of BTG induced cross-linking on the properties of SPI. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) results indicated that almost all protein constituents (α', α, ß, AS, and BS) in SPI could be cross-linked with BTG treatment. The BTG treatment also resulted in a significant increase (*P < 0.05) in SPI mean particle size. Emulsifying activity and stability were improved from 0.11535 m2  g-1 and 48.3% for native SPI to 0.13252 m2  g-1 and 83.9% for SPI treated with BTG at 6 h. Similarly, the modified SPI showed better foam activity (1.32 mL) and stability (87.6%) than the original SPI (0.93 mL and 56.8%). The water-holding capacity of SPI gel was found to increase with time, with a value of 95.43% at 6 h. Furthermore, SPI gel's texture profiles were greatly improved by adding BTG (*P < 0.05). CONCLUSION: The results of the present study indicated that BTG could be a promising cross-linking agent for improving the functional characteristics of SPI. As a substitute for MTG, BTG could thus potentially be used for food structure engineering to enhance the functional characteristics of multiple proteins to advance the development of food chemistry. © 2020 Society of Chemical Industry.

A Particle Swarm Algorithm Based on a Multi-Stage Search Strategy.

Particle swarm optimization (PSO) has the disadvantages of easily getting trapped in local optima and a low search accuracy. Scores of approaches have been used to improve the diversity, search accuracy, and results of PSO, but the balance between exploration and exploitation remains sub-optimal. Many scholars have divided the population into multiple sub-populations with the aim of managing it in space. In this paper, a multi-stage search strategy that is dominated by mutual repulsion among particles and supplemented by attraction was proposed to control the traits of the population. From the angle of iteration time, the algorithm was able to adequately enhance the entropy of the population under the premise of satisfying the convergence, creating a more balanced search process. The study acquired satisfactory results from the CEC2017 test function by improving the standard PSO and improved PSO.

A Diversity Model Based on Dimension Entropy and Its Application to Swarm Intelligence Algorithm.

The swarm intelligence algorithm has become an important method to solve optimization problems because of its excellent self-organization, self-adaptation, and self-learning characteristics. However, when a traditional swarm intelligence algorithm faces high and complex multi-peak problems, population diversity is quickly lost, which leads to the premature convergence of the algorithm. In order to solve this problem, dimension entropy is proposed as a measure of population diversity, and a diversity control mechanism is proposed to guide the updating of the swarm intelligence algorithm. It maintains the diversity of the algorithm in the early stage and ensures the convergence of the algorithm in the later stage. Experimental results show that the performance of the improved algorithm is better than that of the original algorithm.

Co-Evolution of Complex Network Public Goods Game under the Edges Rules.

The reconnection of broken edges is an effective way to avoid drawback for the commons in past studies. Inspired by this, we proposed a public goods game model under the edges rules, where we evaluate the weight of edges by their nodes' payoff. The results proved that the game obtains a larger range of cooperation with a small gain factor by this proposed model by consulting Monte Carlo simulations (MCS) and real experiments. Furthermore, as the following the course of game and discussing the reason of cooperation, in the research, we found that the distribution entropy of the excess average degree is able to embody and predict the presence of cooperation.

Photophysical/Chemistry Properties of Distyryl-BODIPY Derivatives: An Experimental and Density Functional Theoretical Study.

Singlet oxygen is the key element for photodynamic therapy. In this paper, six novel distyryl-BODIPY compounds were synthesized and investigated in detail to fully evaluate their photophysical/chemistry characteristics. Specially, the singlet oxygen (1O2) quantum yield of compounds 2 and 4 each bearing two bromine atoms in their skeleton revealed the position effect of heavy atom for 1O2 production. The 1O2 quantum yield of 4, which was brominated at 2/6 position of BODIPY skeleton, was much higher than that of compound 2, brominated at styryl group with a long distance toward BODIPY core. Importantly, theoretical calculations were carried out to elaborate the essential reason for the difference of 2 and 4 by investigating intersystem crossing rate.

Bonus-based mercenary punishment promotes cooperation in public goods games.

Various regions often adopt punish strategies to solve traffic congestion problems. Punishing defectors is an effective strategy to solve the first-order free-rider problem in a public goods game. But this behavior is costly because the punisher is often also involved in the original joint venture and therefore vulnerable, which jeopardizes the effectiveness of this incentive. As an option, we could hire special players whose sole duty would be to monitor the population and punish defectors. The fines collected by various regions will also be used to subsidize the construction of public transportation. Thereby, we derive inspiration, and propose an improved public goods game model based on bonus and mercenary punishment. Research has shown that after cooperator gives the punisher an appropriate bonus, cooperators can strengthen the punisher, thereby weakening the defector's advantage and indirectly promoting cooperation by stabilizing the punisher's position in the system. In addition, the mechanism of reusing the fines collected from defectors and then subsidize to other players in the system can directly promote the emergence of cooperation.

Nanostructured Porous Polymer with Low Volume Expansion, Structural Distortion, and Gradual Activation for High and Durable Lithium Storage.

Organic compounds exhibit great potential as sustainable, tailorable, and environmentally friendly electrode materials for rechargeable batteries. However, the intrinsic defects of organic electrodes, including solubility, low ionic conductivity, and restricted electroactivity sites, will inevitably decrease the cycling life and capacity. We herein designed and prepared nanostructured porous polymers (NPP) with a simple one-pot method to overcome the above defects. Theoretical calculations and experimental results demonstrate that the as-synthesized NPP exhibited low volume expansion, molecular-structural distortion, and a gradual function activation process during cycling, thus exhibiting superior, high, and durable lithium storage. The gradual molecular distortion during the lithium storage processes provides more redox-active sites for Li storage, increasing the Li-storage capacity. Ex situ spectrum studies reveal the redox reaction mechanism of Li storage and demonstrate a gradual activation process during the repeated charging/discharging until the full storage of 18 Li ions is achieved. Additionally, a real-time observation on the NPP anode by in situ transmission electron microscope reveals a slight volume expansion during the repeating lithiation and delithiation processes, ensuring its structural integrity during cycling. This quantitative work for high-durability lithium storage could be of immediate benefit for designing organic electrode materials.

Two-dimensional polymer nanosheets as a high-performance organic anode for sodium-ion batteries.

Organic compounds have become a potentially important choice for a new generation of energy-storage electrode materials due to their designability, flexibility, green sustainability, and abundance. However, the applications of organic electrode materials are still limited because of their dissolution in electrolytes and low electrical conductivity, which in turn cause poor cycling stability. Here, for the first time, we report 2-amino-4-thiazole-acetic acid (ATA) and its sodium salt, sodium 2-amino-4-thiazol-derived polymer (PATANa), as an anode. The PATANa showed a two-dimensional (2D) nanosheet structure, offering a larger contact area with the electrolyte and a shorter ion-migration path, which improved the ion-diffusion kinetics. The polymer showed excellent cycling stability and outstanding rate capability when tested as an anode for sodium-ion batteries (SIBs). It could deliver a high reversible specific capacity of 303 mA h g-1 at 100 mA g-1 for 100 cycles and maintain a high discharge capacity of 190 mA h g-1 after 1000 long cycle numbers even at a high current density of 1000 mA g-1. This approach of salinizing the polymer opens a new way to develop anode materials for sodium-ion batteries.

Porous Organic Polymer with Hierarchical Structure and Limited Volume Expansion for Ultrafast and Highly Durable Sodium Storage.

Sustainable organic electrode materials, as promising alternatives to conventional inorganic electrode materials for sodium-ion batteries (SIBs), are still challenging to realize long-lifetime and high-rate batteries because of their poor conductivity, limited electroactivity, and severe dissolution. It is also urgent to deeply reveal their electrochemical mechanism and evolution processes. A porous organic polymer (POP) with a conjugated and hierarchical structure is designed and synthesized here. The unique molecule and structure endow the POP with electron delocalization, high ionic diffusivity, plentiful active sites, exceptional structure stability, and limited solubility in electrolytes. When evaluated as an anode for SIBs, the POP exhibits appealing electrochemical properties regarding reversible capacity, rate behaviors, and long-duration life. Importantly, using judiciously combined experiments and theoretical computation, including in situ transmission electron microscopy (TEM), and ex situ spectroscopy, we reveal the Na-storage mechanism and dynamic evolution processes of the POP, including 12-electron reaction process with Na, low volume expansion (125-106% vs the initial 100%), and stable composition and structure evolution during repeating sodiation/de-sodiation processes. This quantitative design for ultrafast and highly durable sodium storage in the POP could be of immediate benefit for the rational design of organic electrode materials with ideal electrochemical properties.

Enhanced cycling stability and rate capability of a graphene-supported commercialized Vat Blue 4 anode for advanced Li-ion batteries.

Commercialized Vat Blue 4 (VB4) has attracted more attention as a promising anode for large-scale applications in Li-ion batteries (LIBs) due to its high electrochemical activity, low price, and large-scale production. However, its moderate solubility results in severe capacity decay and low utilization of active components. Herein, we present a graphene-supported VB4 composite (VB4/rGO) prepared by a facile sonication and hydrothermal process for long cycling stability and high-rate capability. This design can significantly enhance the Li-storage properties, including high capacity (1045 mA h g-1 at 0.1 A g-1), long cycling stability (537 mA h g-1 even over 1000 cycles at 1 A g-1), and rate capability (315 mA h g-1 at 5 A g-1). Strong π-π interaction derived from the aromatic rings within the π-conjugated system (graphene and VB4) and spatial confinement in-between graphene sheets both can suppress the high solubility of VB4 for superior capacity retention. Moreover, conductive graphene and channels in-between nanosheets can simultaneously facilitate the electron and Li+ transfer. This work demonstrates a simple and effective method to improve the electrochemical performance of commercialized Vat dyes and provides a low-cost and large-scale strategy to develop their practical application in the energy storage field.

Enhanced Structural Stability and Volumetric Capacity of a 3D Pyknotic Graphene Conductive Network via a Pillar Effect of Sn Nanoparticles for Sodium-Ion Batteries.

High volumetric capacity and durability anode materials for sodium ion batteries have been urgently required for practical applications. Herein, we reported a Sn-pillared pyknotic graphene conductive network with high-level N-doping. This densely stacked block offers high volumetric Na-ion storage capacity, rapid electrochemical reaction kinetics, and robust structural stability during cycling owing to the high capacity component (metallic Sn ≈847 mAh g-1), high tap density (≈2.63 g cm-3), high conductivity (N doping ≈5 at. %), and strong spatially confined and pillared structure. Moreover, theoretical simulations have indicated that the charge accumulation around the N-doped region is more pronounced compared to the pristine one, and electrons accumulate around the N atom while loss occurs at the Na atom. These studies also suggest that it might possibly contribute to higher conductivity and stronger electrophilic reactivity, thereby resulting in enhanced Na-ion storage performance. As a result, the as-obtained electrode material exhibits competitive volumetric capacity (1462 mAh cm-3 at 0.1 A g-1), cycling performance (1207 mAh cm-3 after 100 cycles), and promising rate behavior simultaneously.

Stacked Cu2-xSe nanoplates with 2D nanochannels as high performance anode for lithium batteries.

Transition metal chalcogenides are considered as promising alternative materials for lithium-ion batteries owing to their relatively high theoretical capacity. However, poor cycle stability combined with low rate capacity still hinders their practical applications. In this work, the Cu-N chemical bonding directed the stacking Cu2-xSe nanoplates (DETA-Cu2-xSe) is developed to solve this issue. Such unique structure with small nanochannels can enhance the reactive site, facilitate the Li-ion transport as well as inhibit the structural collapse. Benefitting of these advantages, the DETA-Cu2-xSe exhibits high specific capacity, better rate capacity and long cyclability with the specific capacities of 565mAhg-1 after 100 cycles at 200 mA g-1 and 368mAhg-1 after 500 cycles at 5000 mA g-1. This novel DETA-Cu2-xSe structure with nanochannels is promising for next generation energy storage and the synthetic process can be extended to fabricate other transition metal chalcogenides with similar structure.

Trust-based partner switching among partitioned regions promotes cooperation in public goods game.

In this paper, the coevolution mechanism of trust-based partner switching among partitioned regions on an adaptive network is studied. We investigate a low-information approach to building trust and cooperation in public goods games. Unlike reputation, trust scores are only given to players by those with whom they have a relationship in the game, depending on the game they play together. A player's trust score for a certain neighbor is given and known by that player only. Players can adjust their connections to neighbors with low trust scores by switching their partners to other players. When switching partners, players divide other nodes in the network into three regions: immediate neighbors as the known region, indirectly connected second-order neighbors as the intermediate region, and other nodes as the unknown region. Such choices and compartmentalization often occur in global and regional economies. Our results show that preference for switching to partners in the intermediate region is not conducive to spreading cooperation, while random selection has the disadvantage of protecting the cooperator. However, selecting new partners in the remaining two regions based on the average trust score of the known region performs well in both protecting partners and finding potential cooperators. Meanwhile, by analyzing the parameters, we find that the influence of vigilance increasing against unsatisfactory behavior on evolution direction depends on the level of cooperation reward.

Nicotinamide phosphoribosyltransferase as a biomarker for the diagnosis of infectious pleural effusions.

Nicotinamide phosphoribosyltransferase (NAMPT) has been reported to be involved in infectious diseases, but it is unknown whether it plays a role in infectious pleural effusions (IPEs). We observed the levels of NAMPT in pleural effusions of different etiologies and investigated the clinical value of NAMPT in the differential diagnosis of infectious pleural effusions. A total of 111 patients with pleural effusion were enrolled in the study, including 25 parapneumonic effusions (PPEs) (17 uncomplicated PPEs, 3 complicated PPEs, and 5 empyemas), 30 tuberculous pleural effusions (TPEs), 36 malignant pleural effusions (MPEs), and 20 transudative effusions. Pleural fluid NAMPT levels were highest in the patients with empyemas [575.4 (457.7, 649.3) ng/ml], followed by those with complicated PPEs [113.5 (103.5, 155.29) ng/ml], uncomplicated PPEs [24.9 (20.2, 46.7) ng/ml] and TPEs [88 (19.4, 182.6) ng/ml], and lower in patients with MPEs [11.5 (6.5, 18.4) ng/ml] and transudative effusions [4.3 (2.6, 5.1) ng/ml]. Pleural fluid NAMPT levels were significantly higher in PPEs (P < 0.001) or TPEs (P < 0.001) than in MPEs. Moreover, Pleural fluid NAMPT levels were positively correlated with the neutrophil percentage and lactate dehydrogenase (LDH) levels and inversely correlated with glucose levels in both PPEs and TPEs, indicating that NAMPT was implicated in the neutrophil-associated inflammatory response in infectious pleural effusion. Further, multivariate logistic regression analysis showed pleural fluid NAMPT was a significant predictor distinguishing PPEs from MPEs [odds ratio (OR) 1.180, 95% confidence interval (CI) 1.052-1.324, P = 0.005]. Receiver-operating characteristic (ROC) analysis demonstrated that NAMPT was a promising diagnostic factor for the diagnosis of infectious effusions, with the areas under the curve for pleural fluid NAMPT distinguishing PPEs from MPEs, TPEs from MPEs, and IPEs (PPEs and TPEs) from NIPEs were 0.92, 0.85, and 0.88, respectively. In conclusion, pleural fluid NAMPT could be used as a biomarker for the diagnosis of infectious pleural effusions.

Biochemical characterization of a tyrosinase from Bacillus aryabhattai and its application.

Although lots of tyrosinases have been isolated from bacteria, few studies are focused on tyrosinases from Bacillus sp.. In this study, a tyrosinase from B. aryabhattai TCCC 111983 (TYR) was functionally expressed, purified, and then biochemically characterized. The recombinant tyrosinase (rTYR) presented a good catalytic activity in a broad temperature and pH range, retaining over 60% of the relative activity at 30 °C-90 °C and 45% at pH 3.0 to 10.0. Especially, rTYR exhibited 20% of its maximum activity at 0 °C, and it also showed a variable stability towards different effectors. It presented high tolerance towards salinity and chloride, retaining 81% of its original activity in 2 M NaCl. Kinetic parameters indicated that rTYR displayed a relatively good affinity for both l-tyrosine and l-DOPA. Additionally, rTYR demonstrated remarkable advantages on efficient decolorizing azo and anthraquinonic food dyes (carmine and erythrosin), and more five industrial dyes with or without mediators in acidic, neutral, and alkaline conditions. As the first report on the tyrosinase from B. aryabhattai, the aforementioned results indicated that rTYR would be potential for food industrial applications.

Enzymatic characterization, molecular dynamics simulation, and application of a novel Bacillus licheniformis laccase.

A new laccase gene from newly isolated Bacillus licheniformis TCCC 111219 was actively expressed in Escherichia coli. This recombinant laccase (rLAC) exhibited a high stability towards a wide pH range and high temperatures. 170% of the initial activity was detected at pH 10.0 after 10-d incubation, and 60% of the initial activity was even kept after 2-h incubation at 70 °C. It indicated that only single type of extreme environment, such as strong alkaline environment (300 K, pH 12) or high temperature (370 K, pH 7), did not show obvious impact on the structural stability of rLAC during molecular dynamics simulation process. But the four loop regions of rLAC where the active site is situated were seriously destroyed when strong alkaline and high temperature environment existed simultaneously (370 K, pH 12) because of the damage of hydrogen bonds and salt bridges. Moreover, this thermo- and alkaline-stable enzyme could efficiently decolorize the structurally differing azo, triphenylmethane, and anthraquinone dyes with appropriate mediator at pH 3.0, 7.0, and 9.0 at 60 °C. These rare characteristics suggested its high potential in industrial applications to decolorize textile dyeing effluent.

Conjugated Porous Polydiaminophenylsulfone-Triazine Polymer-A High-Performance Anode for Li-Ion Batteries.

Organic compounds are promising electrode materials because of their resource sustainability, environmental friendliness, and highly tailorable properties. The porous conjugated polymer shows great potential as an electrode material for its tunable redox nature, conjugated skeleton, and porous structure. Herein, a novel conjugated porous polymer, polydiaminophenylsulfone-triazine, was synthesized by a simple nucleophilic substitution reaction. The conjugated structure and triazine ring can improve the conductivity, charge-transfer efficiency, and physicochemical stability. Also, the porous polymeric framework shows a large specific surface area and high porosity, providing a large contact area with electrolytes and reducing diffusion distance. The polymer demonstrates highly stable cycling performance and good rate capability as an anode for lithium-ion batteries, suggesting a promising strategy to design a competitive electrode material.

Enhancing the thermostability of phospholipase D from Streptomyces halstedii by directed evolution and elucidating the mechanism of a key amino acid residue using molecular dynamics simulation.

To enhance the thermostability of phospholipase D (PLD), error-prone polymerase chain reaction method was used to create mutants of PLD (PLDsh) from Streptomyces halstedii. One desirable mutant (S163F) with Ser to Phe substitution at position 163 was screened with high-throughput assay. S163F exhibited a 10 °C higher optimum temperature than wild-type (WT). Although WT exhibited almost no activity after incubating at 50 °C for 40 min, S163F still displayed 27% of its highest activity after incubating at 50 °C for 60 min. Furthermore, the half-life of S163F at 50 °C was 3.04-fold higher than that of WT. The analysis of molecular dynamics simulation suggested that the Ser163Phe mutation led to the formation of salt bridge between Lys300 and Glu314 and a stronger hydrophobic interaction of Phe163 with Pro341, Leu342, and Trp460, resulting in an increased structural rigidity and overall enhanced stability at high temperature. This study provides novel insights on PLD tolerance to high temperature by investigating the structure-activity relationship. In addition, it provides strong theoretical foundation and preliminary information on the engineering of PLD with improved characteristics to meet industrial demand.

Diaminopyrene modified reduced graphene oxide as a novel electrode material for excellent performance supercapacitors.

In this paper, novel reduced graphene oxide (rGO) composites (DAPrGOs) modified by diaminopyrene (DAP) were successfully synthesized via a facile solvothermal reaction method and used for supercapacitors. Compared with the pristine rGO, the DAPrGO1 electrode showed distinctly better performance (397.63 F g-1 vs. 80.29 F g-1 of pristine rGO at 0.5 A g-1) with small charge transfer resistance. When a symmetric device was fabricated using DAPrGO1 as the active material, it also exhibited a high capacitance of 82.70 F g-1 at 0.5 A g-1 with an energy density of 25.84 W h kg-1 at a power density of 375 W kg-1, and even offered a high power density of 7500 W kg-1 (18.71 W h kg-1) at 10 A g-1. Moreover, the device possessed good electrochemical stability up to 20 000 cycles, implying promising applications in energy storage fields.

Polyanthraquinone-Triazine-A Promising Anode Material for High-Energy Lithium-Ion Batteries.

A novel covalent organic framework polymer material that bears conjugated anthraquinone and triazine units in its skeleton has been prepared via a facile one-pot condensation reaction and employed as an anode material for Li-ion batteries. The conjugated units consist of C═N groups, C═O groups, and benzene groups, which enable a 17-electron redox reaction with Li per repeating unit and bring a theoretical specific capacity of 1450 mA h g-1. The polymer also shows a large specific surface area and a hierarchically porous structure to trigger interfacial Li storage and contribute to an additional capacity. The highly conductive conjugated polymer skeleton enables fast electron transport to facilitate the Li storage. In this way, the polymer electrode shows a large specific capacity and favorable cycling and rate performance, making it an appealing anode choice for the next-generation high-energy batteries.