Two Decarestrictine Analogs from the Soil-Derived Fungus Penicillium sp. YUD18003 Associated with Gastrodia elata.

Two new decarestrictine analogs decarestrictine P and penicitone, together with eight known homologous compounds were isolated from the soil fungus from the rhizosphere of Penicillium sp. YUD18003 related to Gastrodia elata. Their different structures include a decanolides decartestridine P and a long-chain polyhydroxyketone penicitone. The structures of new compounds were determined by nuclear magnetic resonance (NMR) spectroscopic analysis and high resolution electrospray ionization mass spectrometry (HR-ESI-MS), while their absolute configurations were determined by spectroscopic methods, DP4+ probability analysis, modified Snatzke's method and electron circular dichroism (ECD) calculations. All compounds were evaluated for antimicrobial activities.

Silicon/Graphite/Amorphous Carbon as Anode Materials for Lithium Secondary Batteries.

Although silicon is being researched as one of the most promising anode materials for future generation lithium-ion batteries owing to its greater theoretical capacity (3579 mAh g-1), its practical applicability is hampered by its worse rate properties and poor cycle performance. Herein, a silicon/graphite/amorphous carbon (Si/G/C) anode composite material has been successfully prepared by a facile spray-drying method followed by heating treatment, exhibiting excellent electrochemical performance compared with silicon/amorphous carbon (Si/C) in lithium-ion batteries. At 0.1 A g-1, the Si/G/C sample exhibits a high initial discharge capacity of 1886 mAh g-1, with a high initial coulombic efficiency of 90.18%, the composite can still deliver a high initial charge capacity of 800 mAh g-1 at 2 A g-1, and shows a superior cyclic and rate performance compared to the Si/C anode sample. This work provides a facile approach to synthesize Si/G/C composite for lithium-ion batteries and has proven that graphite replacing amorphous carbon can effectively improve the electrochemical performance, even using low-performance micrometer silicon and large size flake graphite.

Interlayer-Expanded MoS2 Enabled by Sandwiched Monolayer Carbon for High Performance Potassium Storage.

Potassium-ion batteries (PIBs) have aroused a large amount of interest recently due to the plentiful potassium resource, which may show cost benefits over lithium-ion batteries (LIBs). However, the huge volume expansion induced by the intercalation of large-sized potassium ions and the intrinsic sluggish kinetics of the anode hamper the application of PIBs. Herein, by rational design, nano-roses assembled from petals with a MoS2/monolayer carbon (C-MoS2) sandwiched structure were successfully synthesized. The interlayer distance of ultrathin C-MoS2 was expanded from original MoS2 of 6.2 to 9.6 Å due to the formation of the MoS2-carbon inter overlapped superstructure. This unique structure efficiently alleviates the mechanical strain, prevents the aggregation of MoS2, creates more active sites, facilitates electron transport, and enhances the specific capacity and K+ diffusion kinetics. As a result, the prepared C-MoS2-1 anode delivers a high reversible specific capacity (437 mAh g-1 at 0.1 A g-1) and satisfying rate performance (123 mAh g-1 at 6.4 A g-1). Therefore, this work provides new insights into the design of high-performance anode materials of PIBs.

A Multifunctional Coating on Sulfur-Containing Carbon-Based Anode for High-Performance Sodium-Ion Batteries.

A sulfur doping strategy has been frequently used to improve the sodium storage specific capacity and rate capacity of hard carbon. However, some hard carbon materials have difficulty in preventing the shuttling effect of electrochemical products of sulfur molecules stored in the porous structure of hard carbon, resulting in the poor cycling stability of electrode materials. Here, a multifunctional coating is introduced to comprehensively improve the sodium storage performance of a sulfur-containing carbon-based anode. The physical barrier effect and chemical anchoring effect contributed by the abundant C-S/C-N polarized covalent bond of the N, S-codoped coating (NSC) combine to protect SGCS@NSC from the shuttling effect of soluble polysulfide intermediates. Additionally, the NSC layer can encapsulate the highly dispersed carbon spheres inside a cross-linked three-dimensional conductive network, improving the electrochemical kinetic of the SGCS@NSC electrode. Benefiting from the multifunctional coating, SGCS@NSC exhibits a high capacity of 609 mAh g-1 at 0.1 A g-1 and 249 mAh g-1 at 6.4 A g-1. Furthermore, the capacity retention of SGCS@NSC is 17.6% higher than that of the uncoated one after 200 cycles at 0.5 A g-1.

Ultra-Thin Wrinkled Carbon Sheet as an Anode Material of High-Power-Density Potassium-Ion Batteries.

Although K+ is readily inserted into graphite, the volume expansion of graphite of up to 60% upon the formation of KC8, together with its slow diffusion kinetics, prevent graphite from being used as an anode for potassium-ion batteries (PIBs). Soft carbon with low crystallinity and an incompact carbon structure can overcome these shortcomings of graphite. Here, ultra-thin two-dimensional (2D) wrinkled soft carbon sheets (USCs) are demonstrated to have high specific capacity, excellent rate capability, and outstanding reversibility. The wrinkles themselves prevent the dense stacking of micron-sized sheets and provide sufficient space to accommodate the volume change of USCs during the insertion/extraction of K+. The ultra-thin property reduces strain during the formation of K-C compounds, and further maintains structural stability. The wrinkles and heteroatoms also introduce abundant edge defects that can provide more active sites and shorten the K+ migration distance, improving reaction kinetics. The optimized USC20-1 electrode exhibits a reversible capacity of 151 mAh g-1 even at 6400 mA g-1, and excellent cyclic stability up to 2500 cycles at 1000 mA g-1. Such comprehensive electrochemical performance will accelerate the adoption of PIBs in electrical energy applications.

Nano-Silicon@Exfoliated Graphite/Pyrolytic Polyaniline Composite of a High-Performance Cathode for Lithium Storage.

In this paper, a Si@EG composite was prepared by liquid phase mixing and the elevated temperature solid phase method, while polyaniline was synthesized by the in situ chemical polymerization of aniline monomer to coat the surface of nano-silicon and exfoliated graphite composites (Si@EG). Pyrolytic polyaniline (p-PANI) coating prevents the agglomeration of silicon nanoparticles, forming a good conductive network that effectively alleviates the volume expansion effect of silicon electrodes. SEM, TEM, XRD, Raman, TGA and BET were used to observe the morphology and analyze the structure of the samples. The electrochemical properties of the materials were tested by the constant current charge discharge and cyclic voltammetry (CV) methods. The results show that Si@EG@p-PANI not only inhibits the agglomeration between silicon nanoparticles and forms a good conductive network but also uses the outermost layer of p-PANI carbon coating to effectively alleviate the volume expansion of silicon nanoparticles during cycling. Si@EG@p-PANI had a high initial specific capacity of 1491 mAh g-1 and still maintains 752 mAh g-1 after 100 cycles at 100 mA g-1, which shows that it possesses excellent electrochemical stability and reversibility.

Fungal polyketides from a rhizospheric soil-derived Penicillium sp. YUD17004 associated with Gastrodia elata.

Five unprecedented polyketide metabolites were isolated and characterized from a rhizospheric soil-derived Penicillium sp. YUD17004. Their diverse structures included two indanone-type polyketides penicillyketides A and B, a phthalide-like polyketides penicillyketide C, a symmetrical chromone dimer penicillyketide D, along with a pyrone derivative pyranlyketide, which were elucidated by spectroscopic data interpretation and quantum chemical electronic circular dichroism calculation. Notably, the structures of penicillyketides A and B feature a highly functionalized indanone ring nucleus, but differ from other indanone-containing polyketides by the alkyl substitution pattern. The structure of penicillyketide C comprises a furanone ring instead of the hydroxycyclopentenone ring characteristic for penicillyketides A and B, and represents an undescribed arrangement within C17 polyketides. Penicillyketide D represented the first example of a chromone homodimer with the bridge at C-2/2'. Penicillyketide B exhibited weak anti-inflammatory activity with an IC50 value of 32 ± 1.0 µM. Penicillyketide D displayed weak cytotoxicity against MCF-7 cell line with an IC50 value of 25 ± 0.9 µM.

Phialocetones A-J, C12 lactones from the rhizospheric soil-derived fungus Phialocephala sp. YUD18001 associated with Gastrodia elata.

Ten undescribed C12 polyketide phialocetones A-J, featuring twelve-, six- and five-membered lactone moieties, were isolated from a rhizospheric soil-derived Phialocephala sp. YUD18001 associated with Gastrodia elata. Their structures were established by NMR spectroscopic analysis and HRMS, while their absolute configurations were determined by computational methods and chemical reactions. All isolated compounds were evaluated for their anti-inflammatory and cytotoxic activities. As a result, phialocetone D exhibited moderate effects against NO production in lipopolysaccharide (LPS)-induced RAW264.7 cells with an IC50 value of 14.77 µM, while phialocetone E showed cytotoxicity against HL-60 and SW480 cell lines with IC50 values of 19.04 and 10.22 µM, respectively.

Altereporenes A-E, five epoxy octa-hydronaphthalene polyketides produced by an endophytic fungus Alternaria sp. YUD20002.

Five previously undescribed epoxy octa-hydronaphthalene polyketides, altereporenes A-E (1-5) were isolated from rice culture of the endophytic fungus Alternaria sp. YUD20002 derived from the tubers of Solanum tuberosum. Their structures were determined on the basis of comprehensive spectroscopic analyses, while the absolute configurations were elucidated by the comparison of experimental and calculated specific rotations. Meanwhile, the antimicrobial, cytotoxic, anti-inflammatory and acetylcholinesterase inhibitory activities of compounds 1-5 were also investigated.

Dynamic Gesture Recognition Algorithm Based on 3D Convolutional Neural Network.

Gesture recognition is one of the important ways of human-computer interaction, which is mainly detected by visual technology. The temporal and spatial features are extracted by convolution of the video containing gesture. However, compared with the convolution calculation of a single image, multiframe image of dynamic gestures has more computation, more complex feature extraction, and more network parameters, which affects the recognition efficiency and real-time performance of the model. To solve above problems, a dynamic gesture recognition model based on CBAM-C3D is proposed. Key frame extraction technology, multimodal joint training, and network optimization with BN layer are used for making the network performance better. The experiments show that the recognition accuracy of the proposed 3D convolutional neural network combined with attention mechanism reaches 72.4% on EgoGesture dataset, which is improved greatly compared with the current main dynamic gesture recognition methods, and the effectiveness of the proposed algorithm is verified.

Numerical Study on the Gas-Solid Flow in a Spouted Bed Installed with a Controllable Nozzle and a Swirling Flow Generator.

The swirling flow technology is adopted on a nozzle of the spouted bed in order to enhance the radial movement of the particles. The hydrodynamic characteristics in a spouted bed with a swirling flow generator installed on the nozzle are numerically investigated based on the two-fluid model (TFM). The traditional spouted bed and spouted bed with an integral swirling blade nozzle (ISBN) are simulated and analyzed. Numerical results show that the dead zone at the cone region of the annulus can be effectively eliminated by using the ISBN. The maximum decrease in particle concentration near the cone region is 72%, and the ISBN structure can significantly improve the comprehensive fluidization degree of the spouted bed when γ equals 86°. The turbulent kinetic energy of gas can be significantly increased by the swirling flow along the radial direction in the spouted bed, especially in the spout region. Also, the swirling flow can promote the radial velocity and granular temperature of the particles in the spouted bed, which is helpful to the radial mixing of particles and gas phase between the central spout and the annulus in the spouted bed. There exists a value of ξ (equals 0.526), which brings the greatest elimination effect of the flow dead zone in the annulus of the limited spouted bed space, and the overall fluidization of the spouted bed has the best performance when ξ = 0.316.

Experimental Study on Gas-Solid Flow in the Spouted Bed under Longitudinal Vortex Effect.

To strengthen the particles radial movement and mixing, the longitudinal vortex generator of a sphere was adopted in the spouted bed in this study. To find the influence of the longitudinal vortex and particle properties on axial and radial velocities of particles in a 152 mm-diametered spouted bed, particle image velocimetry (PIV) was employed. The experimental results show that the addition of the longitudinal vortex generator caused the vortex movement of high-speed gas and induced a considerable secondary fine vortex in the cross section of the spouted bed, and the existence of longitudinal vortex significantly improved the radial velocity of particles, compared with that of the conventional spouted bed. Due to the effect of longitudinal vortex on particles, the phenomenon of early dropping of particles was increasingly obvious with the rise in bed height, and the value of axial velocity of particle phase was negative. With the decrease in the particle diameter, the longitudinal vortex effect of gas-driven particle movement would be enhanced. The longitudinal vortex could enhance particle velocity under a wide range of particle diameters, and the enhancement factor η decreased with the rise in the particle diameter and gradually approaches to 1.