Exterior and Internal Uniform Loading of Pt Nanoparticles on Yolk-Shell La2O3 by Acoustic Levitation Synthesis with Enhanced Photocatalytic Performance

By the deposition of noble metal nanoparticles on a metal oxide substrate with a specific micro-/nanostructure, namely, yolk-shell structure, a remarkable improvement in photocatalytic performance can be achieved by the composites. Nevertheless, noble metal nanoparticles only distribute on the surface shell of metal oxide substrates when the conventional wet-chemistry reduction approach is employed. Herein, we proposed a novel acoustic levitation synthesis of Pt nanoparticles deposited on yolk-shell La2O3. The composites not only displayed well-defined, homogeneous distribution of Pt NPs on the exterior shell of La2O3 and the interior La2O3 core, but an enhanced chemical interaction between Pt and La2O3. The unique structure not only can display improved photocatalytic degradation rate toward methyl orange, but also may show great potential in fields of hydrogen generation, environmental protection, etc. The novel acoustic levitation synthesis can supplement the methodology of synthesizing well dispersed noble metal oxides over the whole yolk-shell structure through noble metal NPs deposition method

Fast Synthesis of Pt Nanocrystals and Pt/Microporous La2O3 Materials Using Acoustic Levitation

Abstract Usually, we must use an appropriate support material to keep the metal species stable and finely dispersed as supported metal nanoparticles for industry application. Therefore, the choice of support material is a key factor in determining the dispersion and particle size of the noble metal species. Here, we report the synthesis of a single-atom Pt material in the solution and supported Pt nanoclusters on microporous La2O3 by a one-step acoustic levitation method without any pretreatment/modification of raw oxide. We have strongly contributed to the synthetic methodology of the surface/interfacial heterogeneous catalysts in this study, and this finding could open another door for synthesis of supported metal nanoparticles on porous materials for environmental catalysis

A Wearable Prefrontal Cortex Oxygen Saturation Measurement System Based on Near Infrared Spectroscopy

The measurement of blood oxygen saturation in the prefrontal cortex (PFC), especially during sleep, is of great significance for clinical research. Herein, we present a wearable PFC oxygen saturation measurement system using dual-wavelength functional near-infrared spectroscopy. The system is well designed for user-friendly donning and has the advantages of comfort, convenience, portability, and affordability. The performance of the proposed system is investigated by the calibration and experimental results. The wearable system has demonstrated great potential to conduct the physiological monitoring of PFC, and it can be widely deployed in daily life

A Wearable Prefrontal Cortex Oxygen Saturation Measurement System Based on Near Infrared Spectroscopy

The measurement of blood oxygen saturation in the prefrontal cortex (PFC), especially during sleep, is of great significance for clinical research. Herein, we present a wearable PFC oxygen saturation measurement system using dual-wavelength functional near-infrared spectroscopy. The system is well designed for user-friendly donning and has the advantages of comfort, convenience, portability, and affordability. The performance of the proposed system is investigated by the calibration and experimental results. The wearable system has demonstrated great potential to conduct the physiological monitoring of PFC, and it can be widely deployed in daily life

Effect of B on microstructure and properties of joints brazed by In-situ Ag-Cu-Zn-Sn filler metal with high Sn content

The copper brazed joints were obtained by induction brazing using in situ synthetic high Sn content silver filler metals with different B contents and the effect of element B on the wettability of filler metals and microstructure and mechanical properties of the joints were studied. With the addition of element B, the spreading area of the filler metals on the copper increases. The microstructure of the joints mainly consists of silver-based solid solution and copper-based solid solution, and the distribution of silver-based solid solution in the brazing seam becomes dispersed with the addition of B. The width of the brazing seam increases significantly with the increase in B content. Meanwhile, the B element was mainly distributed in the Ag-based solid solution. The tensile strength firstly increased and then sharply decreased with B added. The maximum average tensile strength of 206.83 MPa was obtained with a 2% addition of B and the joint fracture pattern is a brittle fracture

Additional file 1: of Fast Synthesis of Pt Nanocrystals and Pt/Microporous La2O3 Materials Using Acoustic Levitation

HAADF-STEM and HRTEM images of Pt particles. (DOCX 2196 kb

Mechanism of oxide film removal by KF-AlF3 and CsF-AlF3 mixed fluxes on Cu and Al base metals and their effect on wettability

CsF-AlF3 was added in different mass percentages to KF-AlF3 flux, and CsF-AlF3/KF-AlF3 mixed fluxes with different components were prepared by ball milling. The melting curves of four kinds of fluxes were measured using differential scanning calorimetry (DSC). The properties of the fluxes were studied by flowing and wetting experiments. The intermetallic compounds (IMCs) at the interface of the filler metal/copper (Cu) base metal were studied by field emission scanning electron microscope (SEM-EDS), electron backscattering diffraction (EBSD). The results showed that as the mass of CsF-AlF3 increased, the solidus and liquidus temperatures of the flux gradually decreased. The flux has better flowability on the Cu and Al surfaces. In the presence of the fluxes, the wettability of the filler metal on the Al is better compared to the wettability on the Cu. Three kinds of IMCs, namely Cu9Al4, CuAl and CuAl2, were found at the interface between filler metal and Cu. The texture strength and deformation degree of CuAl2 with preferred orientation are the largest. The order of formation of IMCs is Cu9Al4, CuAl, CuAl2

Structural basis for the inhibition of SARS-CoV-2 main protease by antineoplastic drug carmofur

The antineoplastic drug carmofur is shown to inhibit the SARS-CoV-2 main protease (Mpro). Here, the X-ray crystal structure of Mpro in complex with carmofur reveals that the carbonyl reactive group of carmofur is covalently bound to catalytic Cys145, whereas its fatty acid tail occupies the hydrophobic S2 subsite. Carmofur inhibits viral replication in cells (EC50 = 24.30 μM) and is a promising lead compound to develop new antiviral treatment for COVID-19

Structure-based discovery of dual pathway inhibitors for SARS-CoV-2 entry

Abstract Since 2019, SARS-CoV-2 has evolved rapidly and gained resistance to multiple therapeutics targeting the virus. Development of host-directed antivirals offers broad-spectrum intervention against different variants of concern. Host proteases, TMPRSS2 and CTSL/CTSB cleave the SARS-CoV-2 spike to play a crucial role in the two alternative pathways of viral entry and are characterized as promising pharmacological targets. Here, we identify compounds that show potent inhibition of these proteases and determine their complex structures with their respective targets. Furthermore, we show that applying inhibitors simultaneously that block both entry pathways has a synergistic antiviral effect. Notably, we devise a bispecific compound, 212-148, exhibiting the dual-inhibition ability of both TMPRSS2 and CTSL/CTSB, and demonstrate antiviral activity against various SARS-CoV-2 variants with different viral entry profiles. Our findings offer an alternative approach for the discovery of SARS-CoV-2 antivirals, as well as application for broad-spectrum treatment of viral pathogenic infections with similar entry pathways