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91.
92.
Sixiang Zhao Yingying Yu Boyu Zhang Pu Feng Congcong Dang Ming Li Liancheng Zhao Liming Gao 《Advanced Optical Materials》2021,9(20):2100907
Amplification of the intensity and dissymmetry factors (glum) of circularly polarized light is desired to broaden the range of applications of circularly polarized luminescence (CPL) because of the small glum values commonly observed for CPL materials and the loss of intensity resulting from circular polarization. In this study, enhanced CPL produced by metal-enhanced fluorescence is successfully achieved by the self-assembly of Au@SiO2 triangular nanoprisms (Au@SiO2TNPs) and fluorophores (sulforhodamine 101 and methylene blue) in chiral cellulose nanocrystal films. By overlapping the plasmon bands of Au@SiO2TNPs and the excitation–emission spectra of fluorophores, both the fluorescence intensity and glum value of CPL are significantly enhanced. For sulforhodamine 101 in the metal-enhanced CPL system, a 52-fold fluorescence enhancement is achieved, and the glum value increased from −0.038 to −0.126. For methylene blue in the metal-enhanced CPL system, a 201-fold enhancement of fluorescence is obtained, and the glum value is enhanced from −0.055 to −0.085. This metal-enhanced CPL film is expected to generate superior circularly polarized light for extensive CPL applications because of its outstanding enhanced CPL, fluorescence amplification, and feasibility for different fluorophores. 相似文献
93.
Tianyong Liu Qian Dang Xunhui Zhou Jin Li Zhen Ge Hang Che Prof. Shaobin Tang Prof. Yi Luo Prof. Jun Jiang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(23):6945-6953
Developing the low-cost and efficient single-atom catalysts (SACs) for nitrogen reduction reaction (NRR) is of great importance while remains as a great challenge. The catalytic activity, selectivity and durability are all fundamentally related to the elaborate coordination environment of SACs. Using first-principles calculations, we investigated the SACs with single transition metal (TM) atom supported on defective boron carbide nitride nanotubes (BCNTs) as NRR electrocatalysts. Our results suggest that boron-vacancy defects on BCNTs can strongly immobilize TM atoms with large enough binding energy and high thermal/structural stability. Importantly, the synergistic effect of boron nitride (BN) and carbon domains comes up with the modifications of the charge polarization of single-TM-atom active site and the electronic properties of material, which has been proven to be the essential key to promote N2 adsorption, activation, and reduction. Specifically, six SACs (namely V, Mn, Fe, Mo, Ru, and W atoms embedded into defective BCNTs) can be used as promising candidates for NRR electrocatalysts as their NRR activity is higher than the state-of-the art Ru(0001) catalyst. In particular, single Mo atom supported on defective BCNTs with large tube diameter possesses the highest NRR activity while suppressing the competitive hydrogen evolution reaction, with a low limiting potential of −0.62 V via associative distal path. This work suggests new opportunities for driving NH3 production by carbon-based single-atom electrocatalysts under ambient conditions. 相似文献
94.
Cong-Luan Tran Thi-Bich-Ngoc Dao Thanh-Nha Tran Dinh-Tri Mai Thi-Minh-Dinh Tran Nguyen-Minh-An Tran Van-Son Dang Thi-Xuyen Vo Thuc-Huy Duong Jirapast Sichaem 《Molecules (Basel, Switzerland)》2021,26(8)
Bioactive-guided phytochemical investigation of Euphorbia antiquorum L. growing in Vietnam led to the isolation of five ent-atisanes, one seco-ent-atisane, and one lathyrane (ingol-type). The structures were elucidated as ent-1α,3α,16β,17-tetrahydroxyatisane (1), ethyl ent-3,4-seco-4,16β,17-trihydroxyatisane-3-carboxylate (2), ent-atisane-3-oxo-16β,17-acetonide (3), ent-3α-acetoxy-16β,17-dihydroxyatisane (4), ent-16β,17-dihydroxyatisane-3-one (5), calliterpenone (6), and ingol 12-acetate (7). Their chemical structures were unambiguously determined by analysis of one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) and high resolution mass spectrometry, as well as by comparison with literature data. Among them, 1 is a new compound while 2 is an ethylated artifact of ent-3,4-seco-4,16β,17-trihydroxyatisane-3-carboxylic acid, a new compound. Isolates were evaluated for alpha-glucosidase inhibition. Compound 3 showed the most significant inhibitory activity against alpha-glucosidase with an IC50 value of 69.62 µM. Further study on mechanism underlying yeast alpha-glucosidase inhibition indicated that 3 could retard the enzyme function by noncompetitive. 相似文献
95.
Dang Huu Phuc Ha Thanh Tung Van-Cuong Nguyen My Hanh Nguyen Thi 《Molecules (Basel, Switzerland)》2021,26(10)
In this study, TiO2/CdS/CdxCu1−xSe, TiO2/CdS/CdxMn1−xSe, and TiO2/CdS/CdxAg2−2xSe thin films were synthesized by chemical bath deposition for the fabrication of photoanode in quantum-dot-sensitized solar cells. As a result, the structural properties of the thin films have been studied by X-ray diffraction, which confirmed the zinc Blende structure in the samples. The optical films were researched by their experimental absorption spectra with different doping concentrations. Those results were combined with the Tauc correlation to estimate the absorption density, the band gap energy, valence band and conduction band positions, steepness parameter, and electron–phonon interaction. Furthermore, the electrical features, electrochemical impedance spectrum and photocurrent density curves were carried out. The result was used to explain the enhancing performance efficiency. 相似文献
96.
Qi Xu Ziyu Chen Borong Zhu Yiming Li Manju B. Reddy Huilin Liu Guodong Dang Qi Jia Xiaojun Wu 《Molecules (Basel, Switzerland)》2021,26(21)
Cinnamon procyanidin oligomers (CPOs) are water-soluble components extracted from cinnamon. This study aims to explore the neuroprotection of B-type CPO (CPO-B) against 1-methyl-4-phenylpyridinium (MPP+)-mediated cytotoxicity and the molecular mechanisms underlying its protection. The results demonstrated that CPO-B showed protection by increasing cell viability, attenuating an intracellular level of reactive oxygen species, downregulating cleaved caspase-3 expression, and upregulating the Bcl-2/Bax ratio. Moreover, CPO-B completely blocked the dephosphorylation of extracellular, signal-regulated kinase 1 and 2 (Erk1/2) caused by MPP+. Treatment with an Erk1/2 inhibitor, SCH772984, significantly abolished the neuroprotection of CPO-B against MPP+. Taken together, we demonstrate that CPO-B from cinnamon bark provided protection against MPP+ in cultured SH-SY5Y cells, and the potential mechanisms may be attributed to its ability to modulate the dysregulation between pro-apoptotic and anti-apoptotic proteins through the Erk1/2 signaling pathway. Our findings suggest that the addition of cinnamon to food or supplements might benefit patients with PD. 相似文献
97.
Celastrus hindsii is a popular medicinal plant in Vietnam and Southeast Asian countries as well as in South America. In this study, an amount of 12.05 g of an α-amyrin and β-amyrin mixture was isolated from C. hindsii (10.75 g/kg dry weight) by column chromatography applying different solvent systems to obtain maximum efficiency. α-Amyrin and β-amyrin were then confirmed by gas chromatography-mass spectrometry (GC-MS), electrospray ionization-mass spectrometry (ESI-MS), and nuclear magnetic resonance (NMR). The antioxidant activities of the α-amyrin and β-amyrin mixture were determined via 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,20-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays with IC50 of 125.55 and 155.28 µg/mL, respectively. The mixture exhibited a high potential for preventing gout by inhibiting a relevant key enzyme, xanthine oxidase (XO) (IC50 = 258.22 µg/mL). Additionally, an important enzyme in skin hyperpigmentation, tyrosinase, was suppressed by the α-amyrin and β-amyrin mixture (IC50 = 178.85 µg/mL). This study showed that C. hindsii is an abundant source for the isolation of α-amyrin and β-amyrin. Furthermore, this was the first study indicating that α-amyrin and β-amyrin mixture are promising in future therapies for gout and skin hyperpigmentation. 相似文献
98.
In this work, utilizing lotus root knot as raw material, nitrogen and oxygen co-doped hierarchical porous carbon with appropriate heteroatom doping, multi-connected 3D pore structure and suitable pore size distribution were produced by carbonization and chemical activation step. The maximum specific surface area the biochar material reached was 3659 m2 g−1. These physical properties exhibit ultrahigh specific capacitance of up to 454.3 F g−1 in a supercapacitor of the three-electrode system under the current density of 1 A g−1 and a capacitance retention rate of 81.5 % within the range of 1∼10 A g−1. Furthermore, the specific capacitance is maintained at 91.5 % of the initial value in a two-electrode system after 10,000 cycles. In a two-electrode system with tetraethylammonium tetrafluoroborate (TEABF4)/acetonitrile (ACN) solution as the electrolyte. The voltage window attained was 3 V with high energy density of 51.4 Wh kg−1 under the power density of 750 W kg−1. These results show that the assembled supercapacitors provide excellent energy and power density at the same time. 相似文献
99.
针对灰参数线性规划（ＬＰＧＰ）求解中的困难，提出了ＬＰＧＰ定位求解的新思路及定位规划、理想模型、临界模型等新概念；研究了定位系数变化对定位规划最优解的影响以及定位最优值的变化范围；定义了定位规划的满意度和满意解．从而可将灰参数线性规划问题化为若干个一般线性规划问题，在一定程度上解决了灰参数线性规划求解与解的评价问题 相似文献
100.
通过对影响锯片耐用性的六种因素的分析，提出，提高Φ1600冷锯机片耐用性的六种措施，即增大锯齿根部园角半径；改善锯片加工工艺；选取合理的齿形；表面滚压处理；锯齿激光强化处理；选择合理的进锯速度。 相似文献