Latest ArticlesThe development of high-precision sensors using flexible piezoelectric materials has the advantages of high sensitivity, high stability, good durability, and lightweight. The main problem with sensing equipment is low sensitivity, which is due to the mismatch between materials and analysis methods, resulting in the inability to effectively eliminate noise. To address this issue, we developed the denoising analysis method to motion signals captured by a flexible piezoelectric sensor fabricated from poly(L-lactic acid) (PLLA) and polydimethylsiloxane (PDMS) materials. Experimental results demonstrate that this improved denoising method effectively removes noise components from neck muscle motion signals, thus obtaining high-quality, low-noise motion signal waveforms. Wavelet decomposition and reconstruction is a signal processing technique that involves decomposing a signal into different scales and frequency components using wavelets and then selectively reconstructing the signal to emphasize specific features or eliminate noise. The study employed the sym8 wavelet basis for wavelet decomposition and reconstruction. In the denoised signals, a high degree of stability and periodic peaks are distinctly manifested, while amplitude and frequency differences among different types of movements also become noticeably visible. As a result of this study, we are enabled to accurately analyze subtle variations in neck muscle motion signals, such as nodding, shaking the head, neck lateral flexion, and neck circles. Through temporal and frequency domain analysis of denoised motion signals, differentiation among various motion states can be achieved. Overall, this improved analytical approach holds broad application prospects across various types of piezoelectric sensors, such as healthcare monitoring, sports biomechanics.
The catalytic oxidation of volatile organic compounds (VOCs) is of considerable significance for the sustainable development of the chemical industry; thus, considerable efforts have been devoted to the exploration of efficient catalysts for use in this reaction. In this regard, the development and utilization of single-atom catalysts (SACs) in VOCs decomposition is a rapidly expanding research area. SACs can be employed as potential catalysts for oxidizing VOC molecules due to their optimal utilization efficiency, unique atomic bonding structures, and unsaturated orbits. Progress has been achieved, while the challenges surrounding precise regulation of the microstructures of SACs for improving their low-temperature efficiency, stability, and product selectivity under practical conditions are remaining. Therefore, elucidating structure-performance relationships and establishing intrinsic modulating mechanisms are urgently required for guiding researchers on how to synthesize effective and stable functional SACs proactively. Herein, recent advances in the design and synthesis of functional SACs for application in the catalytic oxidation of VOCs are summarized. The experimental and theoretical studies revealing higher efficiency, stability, and selectivity of as-prepared functional SACs are being highlighted. Accordingly, the future perspectives in terms of promising catalysts with multi-sized composite active sites and the illustration of intrinsic mechanism are proposed. The rapid intelligent screening of applicable SACs and their industrial applications are also discussed.
Highly selective and remotely communicable nitrogen dioxide (NO2) sensing may contribute to future Internet of Things in environmental monitoring. However, room-temperature NO2 sensing materials such as carbon materials is still less than satisfactory due to their insensitive interaction with target gas. Here, polyethylene imine functionalized three-dimensional (3D) carbon framework (PEI/C framework) has been developed for enhanced selective NO2 sensing, via combined template synthesis and subsequent doping. Typically, the 3D PEI/C framework is observed porous shape with irregular coating. Beneficially, the response of C framework to NO2 increases while those of interfering gases decrease after being functionalized with PEI. Remarkably, the sensor prototypes show a 100 ppb-concentration detection limit at room temperature. Theoretically, such excellent NO2 sensing is attributed to the large specific surface ratio of porous 3D PEI/C framework, in which PEI serves as an active layer for target NO2, while a passivated one for interfering gases. Practically, such PEI/C framework sensor prototype is simulated for NO2 sensing device and communicated with a smartphone, showing great potential in future intelligent environmental monitoring.
Fe-N-C materials have received increasing attention, due to its distinctive catalytic activity. However, the Fe-N coordination number dependence of catalytic ability and mechanism for H2O2 activation remain elusive. Herein, a series of Fe-N-C heterogeneous Fenton-like catalysts with different Fe-N coordination number were prepared for tetracycline degradation. The results demonstrated that samples with Fe-N4 structure exhibited high activity. The excellent performance was mainly ascribed to the high adsorption capacity and the formation of superoxide radicals (•O2−) catalyzed by Fe linked to pyridinic nitrogen. The intermediates and degradation pathways of tetracycline degradation by Fe-N-C/H2O2 system were analyzed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Furthermore, we applied our Fe-N-C catalysts to treat simulated pharmaceutical wastewater with high tetracycline degradation capacity despite high concentrations of organic matter such as oxalic acid and various ionic interferences. Our work reveals the dependence of the activation H2O2 on the Fe-N coordination environment and the degradation mechanism of these catalysts. It provides insights into the prospects for tuning the catalyst in practical applications.
Vanadium pentoxide (V2O5) with a layered structure is of great interest in the field of electrochromic (EC) due to its abundance of color variations. However, there are still a series of problems such as slow ion diffusion, poor electronic conductivity and cyclic stability in the reaction process. Herein, we successfully prepared a stable and fast multi-color electrochromic material V2O5-PEDOT by a simple "one-pot" method. The layer space of V2O5 could be tuned by 3,4-ethylenedioxythiophene (named V2O5-PEDOT) during the dissolution and recrystallization of vanadium oxide. The expanded layer spacing facilitates rapid ion insertion and extraction. PEDOT serves as an internal conductive pillar to improve the overall conductivity of the material. The obtained intercrossing structure of the nanobelts shortens the ion diffusion distance and ensures electrolyte penetration. The V2O5-PEDOT exhibits the fast response time (1.1 s for coloration and 3.5 s for bleaching at 422 nm), high optical contrast (ΔT = 45% at 422 nm and ΔT = 35.2% at 1000 nm), great coloration efficiency (CE = 97.1 cm2/C), and high cyclic stability (86% preserved after 3000 cycles). The electrochromic devices (ECD) were successfully assembled by using V2O5-PEDOT films as ion storage layers and electrochromic layers, demonstrating remarkable performance.
As one of the most promising adoptive T-cell therapies, chimeric antigen receptor T-cell (CAR-T) therapy has acquired Food and Drug Administration (FDA) approval for a variety of products and has been used successfully in the treatment of malignant hematological tumors. CAR-T therapy, on the other hand, faces a number of obstacles in the field of solid tumor therapy that limit its widespread clinical implementation. Significant advances in nanoparticle research in cancer therapy and immunotherapy have been made in recent years, providing novel strategies to address the challenges encountered by CAR-T therapy in the treatment of solid tumors. This review commences with a comprehensive explanation of the basic framework of CAR-T therapy as well as the challenges it faces in the treatment of solid tumors. Subsequently, we encapsulate a summary of the developmental research combining nanoparticles with CAR-T cells for the treatment of solid tumors, which includes gene transfection, cell activation and expansion, targeted infiltration, immune escape inhibition, and combination with other therapies. Coupled with the overview of the research progress, a discussion has been initiated on the challenges and perspectives of CAR-T based on nanoparticles.
Niduenes A−F (1−6), six novel sesterterpenoids with unprecedented 5/5/5/5/6 pentacyclic ring skeleton were isolated from endophytic fungus Aspergillus nidulans. Compounds 1 and 2 represent the first examples of aromatic pentacyclic sesterterpenoids. Their structures and configurations were elucidated by spectroscopic data and single-crystal X-ray diffraction analyses. Compound 4 demonstrated potent resensitization of SW620/AD300 cells to paclitaxel (PTX). Rhodamine 123 accumulation assay and docking analysis further support that 4 inhibitory the efflux function of P-glycoprotein (P-gp).
Two novel fungal metabolites, asperochones A and B, were obtained from an Aspergillus sp. Their structures were determined by 1D/2D nuclear magnetic resonance (NMR) spectroscopy, high resolution electrospray ionization mass spectroscopy (HRESIMS), and single-crystal X-ray diffraction analysis. Asperochone A possesses an intriguing skeleton bearing 5/6/6/6/7/5/5/5 octacyclic ring system, and asperochone B also exhibits an unusual carbon skeleton with five stereochiral centers. Their structures were proposed as heterotrimeric and heterodimeric products of aromatic polyketides. In addition, asperochone A exhibited a potential anti-tuberculosis effect since it showed a moderate potency against Mycobacterium smegmatis.
Hydrogen-bonded organic frameworks (HOFs) are a promising candidate for optical sensing, but the lack of effective design strategies poses significant challenges to the construction of HOFs for organic acid sensing. In this work, the first HOF for organic acid sensing is reported by constructing a multiple-pyridine carbazole-based dense HOF, namely HOF-FJU-206, from a tripyridine-carbazole molecular 3,6-bis(pyridin-4-yl)-9-(4-(pyridin-4-yl)phenyl)-9H-carbazole (CPPY) with carbazole center for luminescence, pyridyl sites for its responsive of hydrogen proton, and narrow channels in the dense framework for the diffusion of hydrogen protons. HOF-FJU-206 exhibits differential responsively fluorescence sensing and recovery properties to formic, acetic, and propionic acids with different molecular sizes and pKa value (acid dissociation constant). The dissociation degree of various acids can be determined by analyzing the slope of changes in both peak wavelength and intensity of in-situ fluorescence, which easily enables the dual-corrective recognition of different acids. The varying degree of protonation at pyridine sites is proved to be the reason for differential sensing of various acids, as demonstrated by 1H NMR spectra, X-ray photoelectron spectroscopy (XPS) characterization, and modeling studies.
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