Flexible sensors with zero Poisson's ratio.

Flexible sensors have been developed for the perception of various stimuli. However, complex deformation, usually resulting from forces or strains from multi-axes, can be challenging to measure due to the lack of independent perception of multiaxial stimuli. Herein, flexible sensors based on the metamaterial membrane with zero Poisson's ratio (ZPR) are proposed to achieve independent detection of biaxial stimuli. By deliberately designing the geometric dimensions and arrangement parameters of elements, the Poisson's ratio of an elastomer membrane can be modulated from negative to positive, and the ZPR membrane can maintain a constant transverse dimension under longitudinal stimuli. Due to the accurate monitoring of grasping force by ZPR sensors that are insensitive to curvatures of contact surfaces, rigid robotic manipulators can be guided to safely grasp deformable objects. Meanwhile, the ZPR sensor can also precisely distinguish different states of manipulators. When ZPR sensors are attached to a thermal-actuation soft robot, they can accurately detect the moving distance and direction. This work presents a new strategy for independent biaxial stimuli perception through the design of mechanical metamaterials, and may inspire the future development of advanced flexible sensors for healthcare, human-machine interfaces and robotic tactile sensing.

Uniform Bi-Bi2O3 nanoparticles/reduced graphene oxide composites for high-performance aqueous alkaline batteries.

Aqueous alkaline batteries (AABs) with the merits of both high energy density and power density have emerged as one of the most promising candidates for the new generation of energy storage devices, while their practical applications are still limited by the lack of high-performance electrode materials, especially for the anode materials. Herein, metallic bismuth-bismuth oxide nanoparticles (Bi-Bi2O3), with numerous heterogeneous interfaces, are successfully anchored and uniformly distributed on reduced graphene oxide (rGO) sheets. When Bi-Bi2O3/rGO-20 electrode is used as the anode material for an AAB, it shows a high specific capacity of 288.0 mA h g-1 (1036.9 F g-1) at 1 A g-1 and good rate capability (74.7% of capacity retention ratio at 20 A g-1). Additionally, in order to match well with a Bi-Bi2O3/rGO-20 anode, CoVSx thin sheets decorated with Ni-Co layered double hydroxide sheets (NiCo-LDH) were successfully constructed via a facile multistep hydrothermal method and a subsequent electrodeposition process. The resulting cathode exhibits a high specific capacity of 306.0 mA h g-1 (2448 F g-1) at 1 A g-1. The assembled CoVSx@NiCo-LDH//Bi-Bi2O3/rGO-20 AAB delivers an outstanding energy density of 106.1 Wh kg-1 at a power density of 789.6 W kg-1. Besides, the as-synthesized Bi-based electrode is also used in aqueous Zn alkaline batteries to further extend its application and the assembled Bi-Bi2O3/rGO-20//Zn batteries possess an ultralong flat discharge plateau and exhibit a specific capacity of 250.6 mA h g-1 at 1 A g-1. The results demonstrate that the as-assembled AAB has huge potential for practical applications and provides an inspiration for the next-generation energy storage devices.

Isocitrate dehydrogenase 1 from Acinetobacter baummanii (AbIDH1) enzymatic characterization and its regulation by phosphorylation.

Acinetobacter baumannii encodes all enzymes required in the tricarboxylic acid (TCA) cycle and glyoxylate bypass except for isocitrate dehydrogenase kinase/phosphatase (IDHKP), which can phosphorylate isocitrate dehydrogenase (IDH) at a substrate-binding Ser site and control the carbon flux in enterobacteria, such as Escherichia coli. The potential kinase was not successfully pulled down from A. baumannii cell lyase; therefore, whether the IDH 1 from A. baumannii (AbIDH1) can be phosphorylated to regulate intracellular carbon flux has not been clarified. Herein, the AbIDH1 gene was cloned, the encoded protein was expressed and purified to homogeneity, and phosphorylation and enzyme kinetics were evaluated in vitro. Gel filtration and SDS-PAGE analyses showed that AbIDH1 is an 83.5 kDa homodimer in solution. The kinetics showed that AbIDH1 is a fully active NADP-dependent enzyme. The Michaelis constant Km is 46.6 (Mn2+) and 18.1 µM (Mg2+) for NADP+ and 50.5 (Mn2+) and 65.4 µM (Mg2+) for the substrate isocitrate. Phosphorylation experiments in vitro indicated that AbIDH1 is a substrate for E. coli IDHKP. The activity of AbIDH1 treated with E. coli IDHKP immediately decreased by 80% within 9 min. Mass spectrometry indicated that the conserved Ser113 of AbIDH1 is phosphorylated. Continuous phosphorylation-mimicking mutants (Ser113Glu and Ser113Asp) lack almost all enzymatic activity. Side-chain mutations at Ser113 (Ser113Thr, Ser113Ala, Ser113Gly and Ser113Tyr) remarkably reduce the enzymatic activity. Understanding the potential of AbIDH1 phosphorylation enables further investigations of the AbIDH1 physiological functions in A. baumannii.

Underlying Differences Between Chinese Omnivores and Vegetarians in the Evaluations of Different Dietary Groups.

Drawing upon self-categorization theory, the present research investigated the attitudes of omnivores and vegetarians toward five dietary groups, including omnivores, conscientious omnivores, semi-vegetarians, vegetarians, and vegans. When they had high (vs. low) meat rationalization, omnivore participants had fewer negative attitudes toward and more positive evaluations of the omnivore groups but more negative attitudes toward and fewer positive evaluations of the vegetarian groups. Vegetarian participants had the most negative attitudes toward the omnivore group, followed by the conscientious omnivore group, the semi-vegetarian group, the vegetarian group, and the vegan group; the vegetarian participants with high meat rationalization (vs. those with low meat rationalization) had more positive evaluations of the omnivore groups. Such findings suggested that high levels of meat-eating rationalization predicted more favorable attitudes toward omnivores among both omnivore and vegetarian participants.

Superior cycling performance of a novel NKVO@polypyrrole composite anode for aqueous rechargeable lithium-ion batteries.

An aqueous rechargeable lithium-ion battery (ARLB) system has been assembled using as-prepared polypyrrole (PPy) to coat Na0.8K0.2K6O15 (NKVO) anode coupled with LiMn2O4 cathode, both immersed in an aqueous LiNO3 solution. The chemical polymerization techniques have been employed to uniformly coat the surface of NKVO with PPy. The phase of NKVO@PPy composite has been characterized by X-ray diffraction; for quantifying PPy content, the thermal gravimetric analysis was performed. Spectroscopy techniques have been used to visualize the microscale morphological changes on the particle surface of NKVO caused by PPy coating. The staircase cyclic voltammetry and galvanic charge-discharge tests have been conducted at various current rates in the voltage range of -1 to 1 V vs. saturated calomel electrode (SCE). The PPy coated NKVO material showed a similar intercalation/deintercalation mechanism to that of pristine NKVO. When subjected to cyclic performance evaluation at a higher rate of 4 A g-1, PPy-coated NKVO@PPy exhibited a preliminary discharge capacity of 115 mA h g-1 and 64.5 mA h g-1 following 400 cycles of charge-discharge with a retention rate of 55.6%, whereas the uncoated NKVO showed only 18.8% capacity retention rate. The significantly improved cyclic capacity retention has been attributed to the PPy coating, which acted as a protective layer preventing the unwanted side reactions, buffering the volume change and simultaneously increasing the electrical conductivity of pristine NKVO electrode during charge-discharge cycles. The decent performance demonstrated that NKVO@PPy is a promising electrode material for ARLB.

Nano-sized SnSbAgx alloy anodes prepared by reductive co-precipitation method used as lithium-ion battery materials.

Nano-sized SnSbAgx alloy anode materials are prepared by reductive co-precipitation method combining with the aging treatment in water bath at 80 degrees C. The microstructure, morphology and electrochemical properties of synthesized SnSbAgx alloy powders are evaluated by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), galvanostatical cycling tests and electrochemical impedance spectroscopy (EIS). The XRD results indicate that the phases are composed of beta-Sn, Sb, Ag3Sb, Ag3Sn and SnSb in the SnSbAgx alloy. The existence of inactive element Ag and the complex multi-step reaction mechanism in SnSbAgx alloy anodes are propitious to improve the structure stability and thus improve the cycling performance. When cycled at a constant current density of 0.1 mA cm(-2) between 0.1 and 1.50 V, SnSbAg alloy shows better performance that the first discharge capacity is 794 mAh g(-1) and the reversible capacity of 20th cycle attains to 327 mAh g(-1). EIS results show that the semicircle relates to the passivation on the surface in the higher frequency zone and the bias relates to the diffusion in the lower frequency zone.