Nitrogen-Doped Hierarchical Heterostructured Aerophobic MoS_(x)/Ni_(3)S_(2)Nanowires by One-pot Synthesis:System Engineering and Synergistic Effect in Electrocatalysis of Hydrogen Evolution Reaction

Non-noble metal electrocatalysis has witnessed rapid and profound performance improvements owing to the emergence of advanced nanosynthetic techniques.Integration of these nanotechniques can lead to synergistic performance enhancement,but such system-engineering strategies are difficult to achieve because of the lack of effective synthesis method.We hereby demonstrate an integrated approach that combines most of the existing nanotechniques in a facile one-pot synthesis.Material characterization reveals that the product shows key features intended by techniques including morphological,structural,doping,heterointerface,and surface wetting engineering.The as-obtained nitrogen-doped hierarchical heterostructured MoS_(x)/Ni_(3)S_(2)nanowires show an overpotential that is only50 mV higher than commercial Pt/C for hydrogen evolution reaction over current densities from 10 to 150 mA cm^(-2).Correlations between the adopted nanotechniques and the electrochemical reaction rates are established by evaluating the impacts of individual techniques on the activation energy,pre-exponential factor,and transfer coefficient.This indepth analysis provides a full account of the synergistic effects and the overall improvement in electrocatalytic performance of hydrogen evolution reaction.This work manifests a generic strategy for multipurpose material design in non-noble metal electrocatalysis.

Multilevel Micro Structures of the Clam Make the Sealing Even Tighter

Excellent fluid sealing performance is crucial to ensuring the safety of important equipment,especially in aerospace field,such as space capsule and fuel chamber.The frequently opening and closing of the sealing devices is particularly important.Driven by this background,clams(Mactra chinensis)which can open and close their double shells with superior sealing performance,are studied in this work.Here,we show that the clam’s sealing ability is the result of its unique multilevel intermeshing microstructures,including hinge teeth and micro-blocks.These microstructures,which resemble gear teeth,engage with each other when the shell closes,forming a tight structure that prevents the infiltration of water from the outside.Furthermore,the presence of micron blocks prevents the penetration of finer liquids.The simulation results of the bionic end seal components show that the multilevel microstructure has a superior sealing effect.This research is expected to be applied to undersea vehicles that require frequent door opening and closing.

Fish Skin-Inspired Janus Hydrogel Coating for Drag Reduction

Comprehensive Summary,In nature,fishes have evolved functional skins with effective hydrodynamic performance and anti-fouling,facilitating predation and escaping from predators.Although a large number of fish scale-inspired structured surfaces have been explored,the incorporation of mucus on the structured surfaces has been largely ignored.Inspired by the skin of Osteichthyes fishes,a Janus hydrogel coating(JHC)is successfully prepared by a two-step UV light irradiation at room temperature.The bottom side of JHC(STH)achieves a shear adhesive strength of 103.3±17.5 kPa and can strongly adhere to a large variety of surfaces,including metals,ceramic and polymers.The top surface of JHC(SLH)replicates the structure of cycloid scales,while the nature of hydrogel mimics the mucus on fish skin.SLH possesses prominent mechanical,anti-swelling,anti-fouling and drag reduction properties.The design strategy for JHC has potential applications in numerous fields,like,pipeline transportation,bioengineering,and shipping industry.

Bph30confers resistance to brown planthopperby fortifying sclerenchyma in rice leaf sheaths

Phloem-feeding insects cause massive losses in agriculture and horticulture.Host plant resistance to phloem-feeding insects is often mediated by changes in phloem composition,which deter insect settling and feeding and decrease viability.Here,we report that rice plant resistance to the phloem-feeding brown planthopper(BPH)is associated with fortification of the sclerenchyma tissue,which is located just beneath the epidermis and a cell layer or two away from the vascular bundle in the rice leaf sheath.We found that BPHs prefer to feed on the smooth and soft region on the surface of rice leaf sheaths called the long-cell block.We identified Bph30 as a rice BPH resistance gene that prevents BPH stylets from reaching the phloem due to the fortified sclerenchyma.Bph30 is strongly expressed in sclerenchyma cells and enhances cellulose and hemicellulose synthesis,making the cell walls stiffer and sclerenchyma thicker.The structurally fortified sclerenchyma is a formidable barrier preventing BPH stylets from penetrating the leaf sheath tissues and arriving at the phloem to feed.Bph30 belongs to a novel gene family,encoding a protein with two leucine-rich domains.Another member of the family,Bph40,also conferred resistance to BPH.Collectively,the fortified sclerenchyma-mediated resistance mechanism revealed in this study expands our understanding of plant-insect interactions and opens a new path for controlling planthoppers in rice.

Pomelo Peel-Inspired 3D-Printed Porous Structure for Efficient Absorption of Compressive Strain Energy

The porous structure in pomelo peel is believed to be responsible for the protection of its fruit from damage during the free falling from a tree.The quantitative understanding of the relationship between the deformation behavior and the porous structure could pave the way for the design of porous structures for efficient energy absorption.Here,a universal feature of pore distribution in pomelo peels along the radial direction is extracted from three varieties of pomelos,which shows strong correlation to the deformation behavior of the peels under compression.Guided by the porous design found in pomelo peels,porous polyether-ether-ketone(PEEK)cube is additively manufactured and possesses the highest ability to absorb energy during compression as compared to the non-pomelo-inspired geometries,which is further confirmed by the finite element simulation.The nature-optimized porous structure revealed here could guide the design of lightweight and high-energy-dissipating materials/devices.

3D printing of bioinspired compartmentalized capsular structure for controlled drug release

Drug delivery with customized combinations of drugs,controllable drug dosage,and on-demand release kinetics is critical for personalized medicine.In this study,inspired by successive opening of layered structures and compartmentalized structures in plants,we designed a multiple compartmentalized capsular structure for controlled drug delivery.The structure was designed as a series of compartments,defined by the gradient thickness of their external walls and internal divisions.Based on the careful choice and optimization of bioinks composed of gelatin,starch,and alginate,the capsular structures were successfully manufactured by fused deposition modeling three-dimensional(3 D)printing.The capsules showed fusion and firm contact between printed layers,forming complete structures without significant defects on the external walls and internal joints.Internal cavities with different volumes were achieved for different drug loading as designed.In vitro swelling demonstrated a successive dissolving and opening of external walls of different capsule compartments,allowing successive drug pulses from the capsules,resulting in the sustained release for about 410 min.The drug release was significantly prolonged compared to a single burst release from a traditional capsular design.The bioinspired design and manufacture of multiple compartmentalized capsules enable customized drug release in a controllable fashion with combinations of different drugs,drug doses,and release kinetics,and have potential for use in personalized medicine.