Aiming at the construction of novel platform for efficient light harvesting, the precise synthesis of a new family of AIEgen‐branched rotaxane dendrimers was successful realized from an ...AIEgen‐functionalized 2rotaxane through a controllable divergent approach. In the resultant AIE macromolecules, up to twenty‐one AIEgens located at the tails of each branches, thus making them the first successful example of AIEgen‐branched dendrimers. Attributed to the solvent‐induced switching feature of the rotaxane branches, the integrated rotaxane dendrimers displayed interesting dynamic feature upon the aggregation‐induced emission (AIE) process. Moreover, novel artificial light‐harvesting systems were further constructed based on these AIEgen‐branched rotaxane dendrimers, which revealed impressive generation‐dependent photocatalytic performances for both photooxidation reaction and aerobic cross‐dehydrogenative coupling (CDC) reaction.
A novel artificial light‐harvesting system based on AIEgen‐branched rotaxane dendrimers has been successfully constructed which displayed impressive generation‐dependent photocatalytic performances for both photooxidation reaction and aerobic cross‐dehydrogenative coupling reaction.
Nitrogen‐doped carbon (NC) materials have been proposed as next‐generation oxygen reduction reaction (ORR) catalysts to significantly improve scalability and reduce costs, but these alternatives ...usually exhibit low activity and/or gradual deactivation during use. Here, we develop new 2D sandwich‐like zeolitic imidazolate framework (ZIF) derived graphene‐based nitrogen‐doped porous carbon sheets (GNPCSs) obtained by in situ growing ZIF on graphene oxide (GO). Compared to commercial Pt/C catalyst, the GNPCSs show comparable onset potential, higher current density, and especially an excellent tolerance to methanol and superior durability in the ORR. Those properties might be attributed to a synergistic effect between NC and graphene with regard to structure and composition. Furthermore, higher open‐circuit voltage and power density are obtained in direct methanol fuel cells.
Nitrogen‐doped: A new oxygen reduction reaction electrocatalyst was obtained from ZIF‐derived porous carbon and graphene. The catalyst exhibits high activity, superior tolerance to methanol, and good stability in comparison to commercial Pt/C catalyst.
Insect gustatory system plays a central role in guiding insect feeding behaviors, insect–plant interactions and coevolutions. Gustatory receptors (GRs) form the interface between the insect taste ...system and their environment. Previously, most studies on insect GRs are focused on Drosophila; much less attention has been paid to Lepidoptera species, which consist of a large number of serious agricultural crop pests. With the exceptional advances in the next generation sequencing (NGS), cellular biology, RNA interference (RNAi), and clustered regularly interspaced short palindromic repeats (CRISPR) technologies in recent years, extraordinary progresses have been achieved elucidating the molecular mechanisms of Lepidopteran GRs. In this review, we highlighted these advances, discussed what these advances have revealed and provide our new insights into this field.
To avoid large open surgery using scaffold transplants, small‐sized cell carriers are employed to repair complexly shaped tissue defects. However, most cell carriers show poor cell adherences and ...viability. Therefore, polyhydroxyalkanoate (PHA), a natural biopolymer, is used to prepare highly open porous microspheres (OPMs) of 300–360 µm in diameter, combining the advantages of microspheres and scaffolds to serve as injectable carriers harboring proliferating stem cells. In addition to the convenient injection to a defected tissue, and in contrast to poor performances of OPMs made of polylactides (PLA OPMs) and traditional less porous hollow microspheres (PHA HMs), PHA OPMs present suitable surface pores of 10–60 µm and interconnected passages with an average size of 8.8 µm, leading to a high in vitro cell adhesion of 93.4%, continuous proliferation for 10 d and improved differentiation of human bone marrow mesenchymal stem cells (hMSCs). PHA OPMs also support stronger osteoblast‐regeneration compared with traditional PHA HMs, PLA OPMs, commercial hyaluronic acid hydrogels, and carrier‐free hMSCs in an ectopic bone‐formation mouse model. PHA OPMs protect cells against stresses during injection, allowing more living cells to proliferate and migrate to damaged tissues. They function like a micro‐Noah's Ark to safely transport cells to a defect tissue.
Combining the advantages of microspheres and scaffolds, highly open porous microspheres (OPMs) made of polyhydroxyalkanoate (PHA) are developed as injectable carriers harboring growing stem cells. The PHA OPMs protect the stem cells from stresses during injection, allowing more living cells to proliferate and migrate to damaged tissues, functioning like a micro‐Noah's Ark to safely transport cells to a designated tissue location for regeneration.
Persistent luminescence is a unique optical process where long‐lasting afterglow persists after the cessation of excitation. Nanoscale persistent luminescent materials are getting increased research ...interest from various fields due to their unique optical property. In recent years, inspiring achievements have been made to produce uniform persistent luminescence nanoparticles (PLNPs) in a controllable manner, unleashing their fascinating potential, surpassing other types of luminescent materials in a wide variety of application such as high‐contrast bioimaging and high‐resolution X‐ray detection. In this review, the evolution of uniform PLNPs, from their bulk phosphor counterparts, to the “top‐down” preparation of nanoscale persistent luminescent materials, to the recent “bottom‐up” synthesis of uniform PLNPs is first summarized. The respective milestones of uniform PLNPs prepared by templated synthesis, aqueous synthesis, and colloidal synthesis are highlighted. The key optical properties that can be enhanced in uniform PLNPs, including increasing the persistent luminescence intensity, tuning the excitation irradiance, as well as the emission wavelengths are then analyzed. Detailed strategies to enhance each optical property are also discussed in various sections. Finally, future challenges are highlighted with respect to the perspectives on the development of next‐generation PLNPs with novel applications.
Persistent luminescence nanoparticles (PLNPs) possess long‐lasting afterglow after the excitation ceases, demonstrating merits for various applications. The recent rapid progress of uniform PLNPs boosts their biomedical applications. This review highlights milestones of uniform PLNPs syntheses, analyzes key strategies for enhancing their optical properties, and envisions the challenges and potential future directions of uniform PLNPs for novel applications.
This letter presents a computationally efficient and robust LiDAR-inertial odometry framework. We fuse LiDAR feature points with IMU data using a tightly-coupled iterated extended Kalman filter to ...allow robust navigation in fast-motion, noisy or cluttered environments where degeneration occurs. To lower the computation load in the presence of a large number of measurements, we present a new formula to compute the Kalman gain. The new formula has computation load depending on the state dimension instead of the measurement dimension. The proposed method and its implementation are tested in various indoor and outdoor environments. In all tests, our method produces reliable navigation results in real-time: running on a quadrotor onboard computer, it fuses more than 1200 effective feature points in a scan and completes all iterations of an iEKF step within 25 ms. Our codes are open-sourced on Github.<xref ref-type="fn" rid="fn1"> 1
Developing cost‐efficient multifunctional electrocatalysts is highly critical for the integrated electrochemical energy‐conversion systems such as water electrolysis based on hydrogen/oxygen ...evolution reactions (HER/OER) and metal‐air batteries based on OER/oxygen reduction reactions (ORR). The core–shell structured materials with transition metal phosphide as the core and nitrogen‐doped carbon (NC) as the shell have been known as promising HER electrocatalysts. However, their oxygen‐related electrocatalytic activities still remain unsatisfactory, which severely limits their further applications. Herein an effective strategy to improve the core and shell performances of core–shell Co2P@NC electrocatalysts through secondary metal (e.g., Fe, Ni, Mo, Al, Mn) doping (termed M‐Co2P@M‐N‐C) is reported. The as‐synthesized M‐Co2P@M‐N‐C electrocatalysts show multifunctional HER/OER/ORR activities and good integrated capabilities for overall water splitting and Zn‐air batteries. Among the M‐Co2P@M‐N‐C catalysts, Fe‐Co2P@Fe‐N‐C electrocatalyst exhibits the best catalytic activities, which is closely related to the configuration of highly active species (Fe‐doping Co2P core and Fe‐N‐C shell) and their subtle synergy, and a stable carbon shell for outstanding durability. Combination of electrochemical‐based in situ Fourier transform infrared spectroscopy with extensive experimental investigation provides deep insights into the origin of the activity and the underlying electrocatalytic mechanisms at the molecular level.
By incorporating various secondary metals (e.g., Fe, Ni, Mo, Mn, and Al) into core–shell Co2P@NC system, the trifunctional catalytic activities of core and shell of Co2P@NC toward HER/OER/ORR is enhanced simultaneously, leading to an advanced catalytic system (Fe‐Co2P@Fe‐N‐C) with high catalytic efficiency and remarkable stability for efficient water electrolysis and rechargeable liquid/all‐solid‐state Zn‐air batteries.
Aiming at the construction of novel stimuli‐responsive fluorescent system with precisely tunable emissions, the typical 9,14‐diphenyl‐9,14‐dihydrodibenzoa, cphenazine (DPAC) luminogen with attractive ...vibration‐induced emission (VIE) behavior has been introduced into 2rotaxane as a stopper. Taking advantage of their unique dual stimuli‐responsiveness towards solvent and anion, the resultant 2rotaxanes reveal both tunable VIE and switchable circularly polarized luminescence (CPL). Attributed to the formation of mechanical bonds, DPAC‐functionalized 2rotaxanes display interesting VIE behaviors including white‐light emission upon the addition of viscous solvent, as evaluated in detail by femtosecond transient absorption (TA) spectra. In addition, ascribed to the regulation of chirality information transmission through anion‐induced motions of chiral wheel, the resolved chiral 2rotaxanes reveal unique switchable CPL upon the addition of anion, leading to significant increase in the dissymmetry factors (glum) values with excellent reversibility. Interestingly, upon doping the chiral 2rotaxanes in stretchable polymer, the blend films reveal remarkable emission change from white light to light blue with significant 6.5‐fold increase in glum values up to −0.035 under external tensile stresses. This work provides not only a new design strategy for developing molecular systems with fluorescent tunability but also a novel platform for the construction of smart chiral luminescent materials for practical use.
The dual stimuli‐responsiveness of novel 2rotaxanes endows them with both tunable vibration‐induced emission and switchable circularly polarized luminescence, providing a novel platform for the construction of smart chiral luminescent materials for practical use.
We consider three dimensional Einstein gravity non-minimally coupled to a real scalar field with a self-interacting scalar potential and present the exact black hole formation in three dimensions. ...Firstly we obtain an exact time-dependent spherically symmetric solution describing the gravitational collapse to a scalar black hole at the infinite time, i.e. in the static limit. The solution can only be asymptotically AdS because of the No–Go theorem in three dimensions which is resulting from the existence of a smooth black hole horizon. Then we analyze their geometric properties and properties of the time evolution. We also get the exact time-dependent solution in the minimal coupling model after taking a conformal transformation.
Coronavirus disease 2019 is a newly emerging infectious disease currently spreading across the world. It is caused by a novel coronavirus, severe acute respiratory syndrome coronavirus 2 ...(SARS-CoV-2). The spike (S) protein of SARS-CoV-2, which plays a key role in the receptor recognition and cell membrane fusion process, is composed of two subunits, S1 and S2. The S1 subunit contains a receptor-binding domain that recognizes and binds to the host receptor angiotensin-converting enzyme 2, while the S2 subunit mediates viral cell membrane fusion by forming a six-helical bundle via the two-heptad repeat domain. In this review, we highlight recent research advance in the structure, function and development of antivirus drugs targeting the S protein.
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