Dendritic Ni33.8Co66.2 alloy microstructures with hexagonal closed-packed phase have been prepared in large-scale by a simple and facile solution phase chemical route, while flowerlike Ni33.4Co66.6 in size of 2.5–5.5 μm was synthesized by solvothermal routes. Experimental results show that the reaction temperature, total concentration of [Ni2+] + [Co2+], and kinds of solvent and surfactants are key factors for controlling the morphology and crystal phase of the NiCo alloy. The possible formation mechanism for the Ni33.8Co66.2 dendrites has been discussed. Magnetic measurements revealed that both of the NiCo2 alloys obtained are ferromagnetic at room temperature. The saturation magnetization value of the Ni33.8Co66.2 dendrites (163.55 emu/g) is lower than that of the flowerlike Ni33.4Co66.6 (195.79 emu/g), but the Ni33.8Co66.2 dendritic structures exhibit an enhanced coercivity value. NiCo2 alloys with different shapes (Ni33.8Co66.2 dendrites and flowerlike Ni33.4Co66.6) have been used as reusable heteroge...

NiCo2 Alloys: Controllable Synthesis, Magnetic Properties, and Catalytic Applications in Reduction of 4-Nitrophenol

Flowerlike Ni−Fe alloy nanostructures composed of nanorods have been synthesized via a facile hydrothermal approach at relatively low temperature (100 °C) independent of surfactants or external mag...

Facile Synthesis and Growth Mechanism of Flowerlike Ni−Fe Alloy Nanostructures

Uniform 3-D flower-like NiCo crystalline nano/microstructures were synthesized by a surfactant-assisted solvothermal process at 120 °C for 10–15 h, which were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy dispersive X-ray spectroscopy (EDX) and vibrating sample magnetometry (VSM). The effects of synthetic parameters such as surfactant, solvent and molar ratio of metal ions on the formation and morphology of NiCo samples were investigated. The experimental results showed that sodium dodecylbenzenesulfonate (SDBS) and solvent ethanol play critical roles in the formation of novel flower-like NiCo alloy assemblies, and the self-assembly evolution was found to be a two-stage growth process. Magnetic hysteresis measurements revealed that the flower-like Ni48Co52 alloy spheres with an average diameter of ca. 800 nm and hierarchical flower-like Ni47Co53 alloys with a size of ca. 5 μm display ferromagnetic behaviors with saturation magnetizations of 111.33 emu g−1 and 103.58 emu g−1, and coercivities of 84.27 Oe and 52.71 Oe, respectively, at room temperature.

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3-D flower-like NiCo alloy nano/microstructures grown by a surfactant-assisted solvothermal process

Three-dimensional nickel–iron (3-D/Ni–Fe) nanostructures are exciting candidates for various applications because they produce more reaction-active sites than 1-D and 2-D nanostructured materials and exhibit attractive optical, electrical and catalytic properties. In this work, freestanding 3-D/Ni–Fe interconnected hierarchical nanosheets, hierarchical nanospheres, and porous nanospheres are directly grown on a flexible carbon fiber paper (CFP) substrate by a single-step hydrothermal process. Among the nanostructures, 3-D/Ni–Fe interconnected hierarchical nanosheets show excellent electrochemical properties because of its high conductivity, large specific active surface area, and mesopores on its walls (vide infra). The 3-D/Ni–Fe hierarchical nanosheet array modified CFP substrate is further explored as a novel electrode for electrochemical non-enzymatic glucose sensor application. The 3-D/Ni–Fe hierarchical nanosheet arrays exhibit significant catalytic activity towards the electrochemical oxidation of glucose, as compared to the 3-D/Ni–Fe hierarchical nanospheres, and porous nanospheres. The 3-D/Ni–Fe hierarchical nanosheet arrays can access a large amount of glucose molecules on their surface (mesopore walls) for an efficient electrocatalytic oxidation process. Moreover, 3-D/Ni–Fe hierarchical nanosheet arrays showed higher sensitivity (7.90 μA μM−1 cm−2) with wide linear glucose concentration ranging from 0.05 μM to 0.2 mM, and the low detection limit (LOD) of 0.031 μM (S/N = 3) is achieved by the amperometry method. Further, the 3-D/Ni–Fe hierarchical nanosheet array modified CFP electrode can be demonstrated to have excellent selectivity towards the detection of glucose in the presence of 500-fold excess of major important interferents. All these results indicate that 3-D/Ni–Fe hierarchical nanosheet arrays are promising candidates for non-enzymatic glucose sensing.

Hierarchical 3-dimensional nickel-iron nanosheet arrays on carbon fiber paper as a novel electrode for non-enzymatic glucose sensing.

Single crystalline FeNi3 dendrites were successfully synthesized in high yield by a simple and facile hydrothermal method without the presence of surfactants and were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), selected area electron diffraction (SAED), energy dispersive X-ray spectroscopy (EDX), and vibrating sample magnetometer (VSM). The individual FeNi3 dendrite consists of a long central trunk with secondary, tertiary, and even quaternary branches. On the dendritic hierarchical structures, several leaves with different lengths of 0.2−2.5 μm and widths of 100 nm to 1 μm are connected to the trunk with a length of 1−5 μm. The reaction parameters such as temperature, the reaction time, the concentration of NaOH, and the initial concentration of Fe3+ ions that affected the FeNi3 morphology were investigated systematically, based on which possible formation mechanism for the dendrites was proposed. Compared with FeNi3 particl...

Single Crystalline FeNi3 Dendrites: Large Scale Synthesis, Formation Mechanism, and Magnetic Properties

Solution phase reduction to Fe–Ni alloy nanostructures with tunable shape and size

Several monoclonal antibodies targeting the programmed cell death-1/programmed cell death-ligand 1 (PD-1/PD-L1) pathway have been used successfully in anticancer immunotherapy. Inherent limitations of antibody-based therapies remain, however, and alternative small-molecule inhibitors that can block the PD-1/PD-L1 axis are urgent needed. Herein, we report the discovery of compound 17 as a bifunctional inhibitor of PD-1/PD-L1 interactions. 17 inhibits PD-1/PD-L1 interactions and promotes dimerization, internalization, and degradation of PD-L1. 17 promotes cell-surface PD-L1 internalized into the cytosol and induces the degradation of PD-L1 in tumor cells through a lysosome-dependent pathway. Furthermore, 17 suppresses tumor growth in vivo by activating antitumor immunity. These results demonstrate that 17 targets the PD-1/PD-L1 axis and induces PD-L1 degradation.

Discovery of Small-Molecule Inhibitors of the PD-1/PD-L1 Axis That Promote PD-L1 Internalization and Degradation.

Predicting the native or near-native binding pose of a small molecule within a protein binding pocket is an extremely important task in structure-based drug design, especially in the hit-to-lead and lead optimization phases. In this study, fastDRH, a free and open accessed web server, was developed to predict and analyze protein-ligand complex structures. In fastDRH server, AutoDock Vina and AutoDock-GPU docking engines, structure-truncated MM/PB(GB)SA free energy calculation procedures and multiple poses based per-residue energy decomposition analysis were well integrated into a user-friendly and multifunctional online platform. Benefit from the modular architecture, users can flexibly use one or more of three features, including molecular docking, docking pose rescoring and hotspot residue prediction, to obtain the key information clearly based on a result analysis panel supported by 3Dmol.js and Apache ECharts. In terms of protein-ligand binding mode prediction, the integrated structure-truncated MM/PB(GB)SA rescoring procedures exhibit a success rate of >80% in benchmark, which is much better than the AutoDock Vina (~70%). For hotspot residue identification, our multiple poses based per-residue energy decomposition analysis strategy is a more reliable solution than the one using only a single pose, and the performance of our solution has been experimentally validated in several drug discovery projects. To summarize, the fastDRH server is a useful tool for predicting the ligand binding mode and the hotspot residue of protein for ligand binding. The fastDRH server is accessible free of charge at http://cadd.zju.edu.cn/fastdrh/.

fastDRH: a webserver to predict and analyze protein-ligand complexes based on molecular docking and MM/PB(GB)SA computation

The anomeric configuration can greatly affect the biological functions and activities of carbohydrates. Herein, we report that N-phenyltrifluoroacetimidoyl (PTFAI), a well-known leaving group for catalytic glycosylation, can act as a stereodirecting group for the challenging 1,2-cis α-glycosylation. Utilizing rapidly accessible 1,6-di-OPTFAI glycosyl donors, TMSOTf-catalyzed glycosylation occurred with excellent α-selectivity and broad substrate scope, and the remaining 6-OPTFAI group can be cleaved chemoselectively. The remote participation of 6-OPTFAI is supported by the first characterization of the crucial 1,6-bridged bicyclic oxazepinium ion intermediates by low-temperature NMR spectroscopy. These cations were found to be relatively stable and mainly responsible for the present stereoselectivities. Further application is highlighted in glycosylation reactions toward trisaccharide heparins as well as the convergent synthesis of chacotriose derivatives using a bulky 2,4-di-O-glycosylated donor.

More than a Leaving Group: N-Phenyltrifluoroacetimidate as a Remote Directing Group for Highly α-Selective 1,2-cis Glycosylation.

Drug design targeting protein-protein interactions (PPIs) associated with the development of diseases has been one of the most important therapeutic strategies. Besides interrupting the PPIs with PPI inhibitors/blockers, increasing evidence shows that stabilizing the interaction between two interacting proteins may also benefit the therapy, such as the development of various types of molecular glues/stabilizers that mostly work by stabilizing the two interacting proteins to regulate the downstream biological effects. However, characterizing the stabilization effect of a stabilizer is usually hard or too complicated for traditional experiments since it involves ternary interactions [protein-protein-stabilizer (PPS) interaction]. Thus, developing reliable computational strategies will facilitate the discovery/design of molecular glues or PPI stabilizers. Here, by fully analyzing the energetic features of the binary interactions in the PPS ternary complex, we systematically investigated the performance of molecular mechanics Poisson-Boltzmann surface area (MM/PBSA) and molecular mechanics generalized Born surface area (MM/GBSA) methods on characterizing the stabilization effects of stabilizers in 14-3-3 systems. The results show that both MM/PBSA and MM/GBSA are powerful tools in distinguishing the stabilizers from the decoys (with area under the curves of 0.90-0.93 for all tested cases) and are reasonable for ranking protein-peptide interactions in the presence or absence of stabilizers as well (with the average Pearson correlation coefficient of ~0.6 at a relatively high dielectric constant for both methods). Moreover, to give a detailed picture of the stabilization effects, the stabilization mechanism is also analyzed from the structural and energetic points of view for individual systems containing strong or weak stabilizers. This study demonstrates a potential strategy to accelerate the discovery of PPI stabilizers.

Hui-Qun Sun

Papers

Solution phase reduction to Fe–Ni alloy nanostructures with tunable shape and size

Discovery of Small-Molecule Inhibitors of the PD-1/PD-L1 Axis That Promote PD-L1 Internalization and Degradation.

fastDRH: a webserver to predict and analyze protein-ligand complexes based on molecular docking and MM/PB(GB)SA computation

More than a Leaving Group: N-Phenyltrifluoroacetimidate as a Remote Directing Group for Highly α-Selective 1,2-cis Glycosylation.

Characterizing the stabilization effects of stabilizers in protein-protein systems with end-point binding free energy calculations