Search

As the most fundamental unit of photonic integration, optical waveguides offer the possibility of developing efficient and practical photonic chips by facilitating the on‐chip integration of devices with different functions. Femtosecond direct laser writing (FsDLW), as a burgeoning 3D microfabrication technology, can realize the rapid formation of arbitrary optical waveguides without any mask inside versatile materials, such as crystalline dielectric crystals, glasses, polymers, and photoresists. This significant material‐independence allows FsDLW to combine different materials and manufacturing processes to implement a cross‐platform solution. This review first describes the different optical loss types and suitable measurement methods for different applicable scenes, then summarizes the two fabrication mechanisms and points out the general direction for adjusting the waveguide properties by fabrication processes. Finally, the application fields and development prospects of different materials are discussed by overviewing the characteristics of different materials and the material selection preferences of different devices. With a panoramic view of the development, it is concluded with insights and perspectives of the future development of optical waveguides and processing technology via FsDLW. [ABSTRACT FROM AUTHOR]

Platelet rich plasma (PRP) is the autologous plasma fraction with a platelet-rich cellular component which is enriched with a number of growth factors. Due to its availability and low cost, PRP has become an increasingly popular clinical tool as an alternative source of growth factors for various applications, for example, tendon regeneration but with limited success in clinical trials. The main objective of the current study was to determine whether activated PRP [i.e., platelet rich plasma-clot release (PRCR)] could be used to induce the proliferation and collagen synthesis in human tenocyte in vitro. The advantage of using PRCR is that the platelet-derived bioactive factors are more concentrated and could initiate a more rapid and accelerated healing response than PRP. Our results demonstrated that 10% PRCR treatment accelerated the extent of cell proliferation and collagen production by human tenocytes in vitro. The expression of specific tenocyte markers were similar to conventional fetal bovine serum (FBS)-treated tenocytes implanted in mice within 14 days of implantation in diffusion chambers. Moreover, relatively more collagen fibrils were evident in PRCR-treated tenocytes in vivo as compared to 10% FBS-treated cells. Overall, our feasibility study has indicated that PRCR can induce human tenocyte proliferation and collagen synthesis which could be implemented for future tendon regeneration in reconstructive surgeries. © 2011 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:982-990, 2012 [ABSTRACT FROM AUTHOR]

The rational design of efficient catalysts for uric acid (UA) electrooxidation, as well as the establishment of structure‐activity relationships, remains a critical bottleneck in the field of electrochemical sensing. To address these challenges, herein, a hybrid catalyst that integrates carbon‐supported Pt nanoparticles and nitrogen‐coordinated Mn single atoms (PtNPs/MnNC) is developed. The metal‐metal interaction during annealing affords the construction of metallic‐bonded Pt−Mn pairs between PtNPs and Mn single atoms, facilitating the electron transfer from PtNPs to the support and thereby optimizing the electronic structure of catalysts. More importantly, experiments and theoretical calculations provide visual proof for the ‘incipient hydrous oxide adatom mediator’ mechanism for UA oxidation. The Pt−Mn pairs first adsorb OH* to construct the bridged Pt−OH−Mn mediators to serve as a highly active intermediate for N−H bond dissociation and proton transfer. Benefiting from the unique electronic and geometric structure of the catalytic center and reactive intermediates, PtNPs/MnNC exhibits superior electrooxidation performance. The electrochemical sensor based on PtNPs/MnNC enables sensitive detection and discrimination of UA and dopamine in serum samples. This work offers new insights into the construction of novel electrocatalysts for sensitive sensing platforms. [ABSTRACT FROM AUTHOR]

Engineering isolated metal sites resembling the primary coordination sphere of metallocofactors enables atomically dispersed materials as promising nanozymes. However, most existing nanozymes primarily focus on replicating specific metallocofactors while neglecting other supporting cofactors within active pockets, leading to reduced electron transfer (ET) efficiency and thus inferior catalytic performances. Herein, we report a metal–organic framework UiO‐67 nanozyme with atomically dispersed iron sites, which involves multiple tailored enzyme‐like nanocofactors that synergistically drive the ET process for enhanced peroxidase‐like catalysis. Among them, the linker‐coupled atomic iron site plays a critical role in substrate activation, while bare linkers and zirconia nodes facilitate the ET efficiency of intermediates. The synergy of three nanocofactors results in a 4.29‐fold enhancement compared with the single effort of isolated metal site‐based nanocofactor, holding promise in immunoassay for sensitive detection of chlorpyrifos. This finding opens a new way for designing high‐performance nanozymes by harmonizing various nanocofactors at the atomic and molecular scale. [ABSTRACT FROM AUTHOR]

Engineering isolated metal sites resembling the primary coordination sphere of metallocofactors enables atomically dispersed materials as promising nanozymes. However, most existing nanozymes primarily focus on replicating specific metallocofactors while neglecting other supporting cofactors within active pockets, leading to reduced electron transfer (ET) efficiency and thus inferior catalytic performances. Herein, we report a metal–organic framework UiO‐67 nanozyme with atomically dispersed iron sites, which involves multiple tailored enzyme‐like nanocofactors that synergistically drive the ET process for enhanced peroxidase‐like catalysis. Among them, the linker‐coupled atomic iron site plays a critical role in substrate activation, while bare linkers and zirconia nodes facilitate the ET efficiency of intermediates. The synergy of three nanocofactors results in a 4.29‐fold enhancement compared with the single effort of isolated metal site‐based nanocofactor, holding promise in immunoassay for sensitive detection of chlorpyrifos. This finding opens a new way for designing high‐performance nanozymes by harmonizing various nanocofactors at the atomic and molecular scale. [ABSTRACT FROM AUTHOR]

Transition metal oxides (TMOs) are promising materials for next‐generation lithium‐ion batteries while the lithium storage and cycling stability of TMOs are still limited. Herein, a novel Co3O4/MnO2/C composite using metal‐organic frameworks (MOFs) as sacrificial templates is reported. MnO2 and C shells are layer by layer coated on the MOF‐derived Co3O4/C samples via hydrothermal technique and heat treatment. When employed as anode materials for LIBs, the hierarchically heterostructured Co3O4/MnO2/C composites incorporate the merits of Co3O4, MnO2, and C, showing high Li storage performances at a current density of 0.2 A g−1 with an initial capacity of ∼1245.7 mAh g−1 and a reversible capacity of ∼854.9 mAh g−1 after 100 cycles, remarkable cycling stability, and excellent rate capability (almost 98 % recovery as the current density returns to the initial 0.2 A g−1, and especially, the specific capacity remains ∼587.6 mAh g−1 at a high current density of 2.0 A g−1). [ABSTRACT FROM AUTHOR]

Reducing carbon emissions is a crucial way to achieve the goal of green and sustainable development. To accomplish this goal, electric vehicles (EVs) are considered system‐schedulable energy storage devices, suppressing the negative impact of the randomness and fluctuation of renewable energy on the system's operation. In this paper, a coordination control strategy aimed at minimising the carbon emissions of a distribution network between EVs, energy storage devices, and static var compensators (SVCs) is proposed. A model‐free deep reinforcement learning (DRL)‐based approach is developed to learn the optimal control strategy with the constraint of avoiding system overload caused by random EV access. The twin‐delayed deep deterministic policy gradient (TD3) framework is applied to design the learning method. After the model learning is completed, the neural network can quickly generate a real‐time low‐carbon scheduling strategy according to the system operating situation. Finally, simulation on the IEEE 33‐bus system verifies the effectiveness and robustness of this method. On the premise of meeting the charging demand of electric vehicles, this method can optimise the system operation by controlling the charge‐discharge process of EVs, effectively absorbing the renewable energy in the system and reducing the carbon emissions of the system operation. [ABSTRACT FROM AUTHOR]