A free-standing graphene-polypyrrole hybrid paper via electropolymerization with an enhanced areal capacitance

Here we developed a free-standing reduced graphene oxide (rGO)-polypyrrole (PPy) hybrid paper via electropolymerization on a paper-like graphene gel. This flexible hybrid paper displayed a uniform layered structure with PPy coated onto the graphene layers. A high areal mass of 2.7 mg cm−2 could be obtained. It delivered a greatly enhanced areal capacitance of 440 mF cm−2 at 0.5 A g−1, in contrast to that 151∼198.5 mF cm−2 previously reported for graphene paper or polypyrrole-graphene paper. It can retain ∼81% of the initial capacitance at a high current density of 6 A g−1. The combined high flexibility with outstanding electrochemical performance, makes such novel hybrid paper a promising electrode for flexible supercapacitors

Toward biodegradable Mg-air bioelectric batteries composed of silk fibroin-polypyrrole film

Biodegradable active implantable devices can be used to diagnose and/or treat disease and eventually disappear without surgical removal. If an external energy source is required for effective operation then a biocompatible and biodegradable battery would be ideal. In this study, a partially biodegradable Mg-air bioelectric battery (biobattery) is demonstrated using a silk fibroin-polypyrrole (SF-PPy) film cathode coupled with bioresorbable Mg alloy anode in phosphate buffered saline (PBS) electrolyte. PPy is chemically coated onto one side of the silk substrate. SF-PPy film shows a conductivity of ≈1.1 S cm−1 and a mild catalytic activity toward oxygen reduction. It degrades in a concentrated buffered protease XIV solution, with a weight loss of 82% after 15 d. The assembled Mg-air biobattery exhibits a discharge capacity up to 3.79 mA h cm−2 at a current of 10 μA cm−2 at room temperature, offering a specific energy density of ≈4.70 mW h cm−2. This novel partially biodegradable battery provides another step along the route to biodegradable batteries

A robust free-standing MoS2/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) film for supercapacitor applications

Two-dimensional molybdenum disulfide (MoS2) is a promising energy storage material due to its high surface area and unique electronic structure. Free-standing flexible MoS2-based electrode is of importance for use in flexible energy storage devices, whereas there are limited reports available. In this work we developed a robust hybrid film, MoS2 incorporated with highly conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate). This free-standing film possesses excellent mechanical properties with a fracture strength of 18.0 MPa and a Young\u27s modulus of 2.0 GPa. It can deliver a large volumetric capacitance of 141.4 F cm-3, a high volumetric energy density of 4.9 mWh cm-3, and a capacitance retention rate of 98.6% after 5000 charge/discharge cycles. This film has demonstrated its application in an all-solid-state bendable supercapacitor as well

A robust free-standing MoS2/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) film for supercapacitor applications

Two-dimensional molybdenum disulfide (MoS2) is a promising energy storage material due to its high surface area and unique electronic structure. Free-standing flexible MoS2-based electrode is of importance for use in flexible energy storage devices, whereas there are limited reports available. In this work we developed a robust hybrid film, MoS2 incorporated with highly conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate). This free-standing film possesses excellent mechanical properties with a fracture strength of 18.0 MPa and a Young\u27s modulus of 2.0 GPa. It can deliver a large volumetric capacitance of 141.4 F cm-3, a high volumetric energy density of 4.9 mWh cm-3, and a capacitance retention rate of 98.6% after 5000 charge/discharge cycles. This film has demonstrated its application in an all-solid-state bendable supercapacitor as well

Diversity and bioactivity of cultured aquatic fungi from the High Arctic region

This study assessed the diversity and α-glycosidase inhibitory activity of cultured fungi isolated from four aquatic environments (stream, pond, glacial ice, and estuary) in the Ny-Ålesund region (Svalbard, Norway, High Arctic). A total of 134 fungal isolates were obtained from 13 water samples. Based on morphological characteristics and sequence analyses of the nuclear ribosomal DNA internal transcribed spacer region, these fungal isolates were identified as belonging to 47 species, with 26 belonging to the Ascomycota, 20 to the Basidiomycota, and one to the Zygomycota. The most frequently detected fungal species were Vishniacozyma sp. 2, Cadophora sp. 2, Phenoliferia sp. 1, Dioszegia sp. 2, and Mortierella sp.; these species occurred in 10, eight, seven, six, and five of the samples, respectively. Among the 134 fungal isolates, 17 isolates of 15 species displayed high α-glycosidase inhibitory activity in culture. The results suggest that diverse and distinct populations of cultured fungi are present in Arctic aquatic environments, and they include taxa that are potential sources of bioactive molecules that may be used as prototype drugs for medicinal proposals

The impact of social comparison on the neural substrates of reward processing: An event-related potential study

Event-related potentials (ERPs) were recorded to explore the electrophysiological correlates of reward processing in the social comparison context when subjects performed a simple number estimation task that entailed monetary rewards for correct answers. Three social comparison stimulus categories (three relative reward levels/self reward related to the other subject\u27s) were mainly prepared: Self:Other=1:2 (Disadvantageous inequity condition); Self:Other=1:1 (Equity condition); and Self:Other=2:1 (Advantageous inequity condition). Results showed that: both Disadvantageous and Advantageous inequity elicited a more negative ERP deflection (N350–550) than did Equity between 350 and 550 ms, and the generators of N350–550 were localized near the parahippocampal gyrus and the medial frontal/anterior cingulate cortex, which might be related to monitor and control reward prediction error during reward processing. Then, Disadvantageous and Advantageous inequity both elicited a more late negative complex (LNC1 and LNC2) than did Equity between 550 and 750 ms. The generators of LNC1 and LNC2 were both localized near the caudate nucleus, which might be related to reward processing under social comparison

Visualizing the Localized Electrons of a Kagome Flat Band

Destructive interference between electron wavefunctions on the two-dimensional (2D) kagome lattice induces an electronic flat band, which could host a variety of interesting many-body quantum states. Key to realize these proposals is to demonstrate the real space localization of kagome flat band electrons. In particular, the extent to which the often more complex lattice structure and orbital composition of realistic materials counteract the localizing effect of destructive interference, described by the 2D kagome lattice model, is hitherto unknown. We used scanning tunneling microscopy (STM) to visualize the non-trivial Wannier states of a kagome flat band at the surface of CoSn, a kagome metal. We find that the local density of states associated with the flat bands of CoSn is localized at the center of the kagome lattice, consistent with theoretical expectations for their corresponding Wannier states. Our results show that these states exhibit an extremely small localization length of two to three angstroms concomitant with a strongly renormalized quasiparticle velocity, which is comparable to that of moir\'e superlattices. Hence, interaction effects in the flat bands of CoSn could be much more significant than previously thought. Our findings provide fundamental insight into the electronic properties of kagome metals and are a key step for future research on emergent many-body states in transition metal based kagome materials

A novel intelligent adaptive control of laser-based ground thermal test

AbstractLaser heating technology is a type of potential and attractive space heat flux simulation technology, which is characterized by high heating rate, controlled spatial intensity distribution and rapid response. However, the controlled plant is nonlinear, time-varying and uncertainty when implementing the laser-based heat flux simulation. In this paper, a novel intelligent adaptive controller based on proportion–integration–differentiation (PID) type fuzzy logic is proposed to improve the performance of laser-based ground thermal test. The temperature range of thermal cycles is more than 200K in many instances. In order to improve the adaptability of controller, output scaling factors are real time adjusted while the thermal test is underway. The initial values of scaling factors are optimized using a stochastic hybrid particle swarm optimization (H-PSO) algorithm. A validating system has been established in the laboratory. The performance of the proposed controller is evaluated through extensive experiments under different operating conditions (reference and load disturbance). The results show that the proposed adaptive controller performs remarkably better compared to the conventional PID (PID) controller and the conventional PID type fuzzy (F-PID) controller considering performance indicators of overshoot, settling time and steady state error for laser-based ground thermal test. It is a reliable tool for effective temperature control of laser-based ground thermal test

Hawthorn Procyanidins Regulate Lipid Metabolism through the AMPK/SREBP-1c Signaling Pathway

Objective: To investigate the effect of hawthorn procyanidins (HPC) on lipid metabolism and its mechanism by regulating the AMP-activated protein kinase/sterol regulatory element binding protein-1c (AMPK/SREBP-1c) signaling pathway. Methods: Sixty rats were randomly divided into six groups (n = 10) blank control (BC), hyperlipidemia model (HM), low-, medium-, and high-dose HPC (HPC-LD, HPC-MD, and HPC-HD) and fenofibrate positive control (FP). The contents of triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) in the serum and liver homogenate were measured by commercial kits. Hematoxylin eosin (HE) staining was used to observe hepatic histopathological changes. The mRNA expression levels of AMPK, SREBP-1c, glycerol-3-phosphate acyltransferase-1 (GPAT1), acetyl CoA carboxylase (ACC), fatty acid synthase (FAS), carnitine palmitoyltransterase-1 (CPT1) and peroxisome proliferator activated receptor γ coactivator-1α (PGC-1α) in the liver were measured by quantitative real-time polymerase chain reaction (PCR). Western blotting was used to detect the protein expression of p-AMPK, SREBP-1c, GPAT1, ACC, FAS, CPT1 and PGC-1α in the liver. Results: After seven weeks of feeding on a high-fat diet, body mass, liver mass and liver index significantly increased compared with the control group fed on a basal diet (P < 0.05 or < 0.01). Compared with the HM group, the contents of TG, TC and LDL-C in serum and liver homogenate in the HPC-HD and FP groups significantly decreased, and the content of HDL-C significantly increased (P < 0.01); the effect of HPC on lipid content in serum and liver homogenate was dose-dependent. After prophylactic intervention with HPC, the steatosis of hepatocytes was gradually improved with an increase in the dosage of HPC. Compared with the HM group, the AMPK mRNA expression and p-AMPK protein expression in liver tissues in the HPC-HD and FP groups significantly increased (P < 0.01), and the mRNA and protein expression of SREBP-1c, GPAT1, ACC and FAS significantly decreased (P < 0.01), and the mRNA and protein expression of CPT1 and PGC-1α significantly increased in the liver (P < 0.01). Conclusion: HPC can effectively improve lipid metabolism in hyperlipidemic rats, which may be related to the regulation of the AMPK/SREBP-1c signaling pathway