The manufacture of bionic materials to simulate the natural counterparts has attracted extensive attention. As one of the subcategories of biomimetic materials, the development of artificial enzyme ...is intensive pursuing. As a kind of artificial enzyme, nanozymes are dedicated to solve the limitations of natural enzymes. In recent years, attributed to the explosive development of nanotechnology, biotechnology, catalysis science, computational design and theory calculation, research on nanozymes has made great progress. To highlight these achievements and help researchers to understand the current investigation status of nanozyme, the state‐of‐the‐art development in nanozymes from fabrication materials to bioapplications are summarized. First different raw materials are summarized, including metal‐based, metal‐free, metal‐organic frameworks‐based, and some other novel matters, which are applied to fabricate nanozymes. The different types of enzymes‐like catalytic activities of nanozymes are briefly discussed. Subsequently, the wide applications of nanozymes such as anti‐oxidation, curing diseases, anti‐bacteria, biosensing, and bioimaging are discussed. Finally, the current challenges faced by nanozymes are outlined and the future directions for advancing nanozyme research are outlooked. The authors hope this review can inspire research in the fields of nanotechnology, chemistry, biology, materials science, and theoretical computing, and can contribute to the development of nanozymes.
To highlight these achievements and help researchers to understand the current investigation status of nanozyme, the state‐of‐the‐art development in nanozymes from fabrication materials and catalytic properties to anti‐oxidation, curing diseases, anti‐bacteria, biosensing, bioimaging, and the like are summarized in this review. Furthermore, the challenges faced by nanozymology are outlined and the future directions for advancing nanozyme research are outlooked.
Thermally conductive yet electrically insulating polymer composites are urgently required for thermal management applications of modern electrical systems and electronic devices because of their ...multifunctionality and ease of processing. However, the thermal conductivity enhancement of polymer composites is usually at the price of the loss of lightweight, the deterioration of flexibility, and electrical insulation. Here we report advanced polymer nanocomposites containing orientated boron nitride nanosheets (BNNSs), which simultaneously exhibit high thermal conductivity enhancement, excellent electrical insulation, and outstanding flexibility. These nanocomposite films can be easily constructed by electrospinning polymer/BNNSs nanocomposite fibers, vertically folding the electrospun nanocomposite fibers and the subsequent pressing. The nanocomposite films exhibit thickness-dependent in-plane thermal conductivity, which can reach 16.3 W/(m·K) in the 18 μm thick nanocomposite film with 33 wt % BNNSs. In addition, the nanocomposite films have superior electrically insulating properties compared with the pristine polymer, such as reduced dielectric loss, increased electrical resistivity, and enhanced breakdown strength. The strong thermal management capability of the nanocomposite film was demonstrated in switching power supply, which showed the importance of high in-plane thermal conductivity in thermal management of high-power density electronic devices.
High‐entropy alloys nanoparticles (HEANPs) are receiving extensive attention due to their broad compositional tunability and unlimited potential in bioapplication. However, developing new methods to ...prepare ultra‐small high‐entropy alloy nanoparticles (US‐HEANPs) faces severe challenges owing to their intrinsic thermodynamic instability. Furthermore, there are few reports on studying the effect of HEANPs in tumor therapy. Herein, the fabricated PtPdRuRhIr US‐HEANPs act as bifunctional nanoplatforms for the highly efficient treatment of tumors. The US‐HEANPs are engineered by the universal metal‐ligand cross‐linking strategy. This simple and scalable strategy is based on the aldol condensation of organometallics to form the target US‐HEANPs. The synthesized US‐HEANPs exhibit excellent peroxidase‐like (POD‐like) activity and can catalyze the endogenous hydrogen peroxide to produce highly toxic hydroxyl radicals. Furthermore, the US‐HEANPs possess a high photothermal conversion effect for converting 808 nm near‐infrared light into heat energy. In vivo and in vitro experiments demonstrated that under the synergistic effect of POD‐like activity and photothermal action, the US‐HEANPs can effectively ablate cancer cells and treat tumors. It is believed that this work not only provides a new perspective for the fabrication of HEANPs, but also opens the high‐entropy nanozymes research direction and their biomedical application.
The ultra‐small PtPdRuRhIr high‐entropy alloy nanoparticles (US‐HEANPs) are fabricated by the universal metal‐ligand cross‐linking strategy. This strategy takes advantage of simplicity, scalability, and genericity. The developed US‐HEANPs exhibit excellent peroxidase‐like activity and possess a high photothermal conversion effect. Under the synergistic effects of peroxidase‐like activity and photothermal action, the US‐HEANPs can effectively ablate cancer cells and treat tumors.
Piezoelectric nanogenerators (PENGs) with good flexibility and high outputs have promising and outstanding applications for harvesting mechanical energy and powering electronics. In this work, PENGs ...are fabricated by using electrospun nanocomposite fiber mats comprising barium titanate (BT) nanoparticles, graphene nanosheets and poly(vinylidene fluoride) (PVDF). When the nanocomposite fiber mats are composed of 0.15 wt% graphene nanosheets and 15 wt% BT nanoparticles, the open-circuit voltage and electric power of the PENG can reach as high as 11 V and 4.1 μW under a loading frequency of 2 Hz and a strain of 4 mm, and no apparent decline of the open-circuit voltage is observed after 1800 cycles in the durability test. In addition, the PENG generate a peak voltage as high as 112 V during a finger pressing-releasing process, which can light up 15 LEDs and drive an electric watch. The improved output of the PENG is ascribed to the synergistic contribution of the BT nanoparticles and graphene nanosheets to the piezoelectric performance enhancement of the nanocomposite fibers. This study shows that the nanocomposite fiber based flexible PENGs are promising mechanical energy harvesters and effective power sources for portable electronic and wearable devices.
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•The interfacial interaction enhances the β phase crystallization of PVDF.•Synergistic effect of BT and graphene greatly improves the piezoelectric outputs.•The electric outputs of PENGs are influenced by load frequency and strain.•The flexible PENGs with high electric outputs exhibit high durability.•The PENGs can be applied as sensors or an energy harvesters.
Flash memory has become a ubiquitous solid-state memory device widely used in portable digital devices, computers and enterprise applications. The development of the information age has demanded ...improvements in memory speed and retention performance. Here we demonstrate an ultrafast non-volatile flash memory based on MoS
/hBN/multilayer graphene van der Waals heterostructures, which achieves an ultrafast writing/erasing speed of 20 ns through two-triangle-barrier modified Fowler-Nordheim tunnelling. Using detailed theoretical analysis and experimental verification, we postulate that a suitable barrier height, gate coupling ratio and clean interface are the main reasons for the breakthrough writing/erasing speed of our flash memory devices. Because of its non-volatility this ultrafast flash memory could provide the foundation for the next generation of high-speed non-volatile memory.
Due to complexity and diversity of the real tunnel structures and fire scenes, there exist few effective methods for temperature prediction of the underground tunnel fire. Hence, here a data-driven ...adaptive modified ant colony optimization (ACO) algorithm is developed to predict the global temperature field of the underground tunnel fire. The algorithm is not limited to the special tunnel structure and fire scene, in which temperature of the underground tunnel fire can be predicted based solely on some sensor data. Meanwhile, to solve the problem that the choice of the model parameters is usually case by case in the traditional ACO algorithms, the model parameters can be adjusted and determined adaptively in the improved algorithm. A numerical example of full scale fire test of an underground tunnel is used to verify the ability and effectiveness of the developed algorithm. The results show that the maximal error is less than 10%. The developed algorithm can be used to predict global temperature with respect to time of the underground tunnel fire, which is easy to be used in engineering application due to its advantages.
Developing biodegradable materials such as poly(lactic acid) (PLA) is a promising strategy to reduce the reliance on non‐degradable plastics and the accumulation of those wastes. However, the ...fabrication of high‐performance biodegradable films which integrate excellent mechanical and barrier properties remains a major challenge. To address this problem, the “brick and mortar” structure, one of the most effective biomimetic models, is introduced to improve the comprehensive properties of materials. Here, a PLA‐assisted exfoliation and dispersion method to prepare the PLA coated mica nanosheets (Nano‐mica/PLA) from a natural mineral phlogopite is presented. By introducing the sheer force assembly, a kind of nacre‐inspired nanocomposite film with the “brick and mortar” structure can be fabricated. Such a nacre‐inspired nanocomposite film shows excellent mechanical properties, UV‐shielding, and gas barrier properties. The overall performance of the nacre‐inspired nanocomposite film is superior to commercial plastic films, which will allow it possible to break a path for practical applications of PLA in the field of packaging.
An advanced poly(lactic acid)‐assisted exfoliation and dispersion method has been developed to prepare the poly(lactic acid) coated mica nanosheets. By introducing the sheer force assembly, a nacre‐inspired nanocomposite film with the “brick and mortar” structure is constructed with the high strength, excellent UV‐shielding performance, and barrier properties, which has great application potential in the field of packaging materials.
Widely used disposable plastic tableware is usually buried or directly discharged into the natural environment after using, which poses potential threats to the natural environment and human health. ...To solve this problem, nondegradable plastic tableware needs to be replaced by tableware composed of biodegradable structural materials with both food safety and the excellent mechanical and thermal properties. Here, a food‐safe sargassum cellulose nanofiber (SCNF) is extracted from common seaweed in an efficient and low energy consuming way under mild reaction conditions. Then, by assembling the SCNF into a dense bulk material, a strong sargassum cellulose nanofiber structural material (SCNSM) with high strength (283 MPa) and high thermal stability (>160 °C) can be prepared. The SCNSM also possesses good machinability, which can be processed into tableware with different shapes, e.g., knives and forks. The overall performance of the SCNSM‐based tableware is better than commercial plastic, wood‐based, and poly(lactic acid) tableware, which shows great application potential in the tableware field.
A food‐safe sargassum cellulose nanofiber (SCNF) is extracted through an efficient and low energy consuming way. Then, by assembling the SCNF into a dense bulk material, a strong structural material can be prepared. It possesses good machinability, which can be processed into tableware with better overall performance than that of commercial tableware, showing great application potential in the tableware field.
Free-Floating Cyst in the Vitreous Sun, Chuan-bin
The New England journal of medicine,
01/2022, Letnik:
386, Številka:
1
Journal Article
Recenzirano
A healthy 18-year-old man presented to the eye clinic with a 1-day history of seeing a “floating ball” in his left eye when he blinked. Slit-lamp examination (shown in a video) revealed a spherical, ...brown-pigmented mass floating freely in the vitreous when the patient blinked. A diagnosis of iris pigment epithelium cyst was made.
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