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991.
Mitochondria is the main organelle for the production of reactive sulfur species (RSS), such as homocysteine (Hcy), cysteine (Cys), glutathione (GSH) and sulfur dioxide (SO2). These compounds participate in a large number of physiological processes and play an extremely important role in maintaining the balance of life systems. Abnormal concentration and metabolism are closely related to many diseases. Due to their similarities in chemical properties, it is challenging to develop a single fluorescent probe to distinguish them simultaneously. Here, we synthesized the probe PI-CONBD with three fluorophores, NBD-Cl and benzopyranate as the reaction sites of GSH/Cys/Hcy and SO2, respectively. Three biothiols all could cleavage ether bond to release benzopyrylium and coumarin moiety, which emitted red and blue fluorescence, but Cys/Hcy also could do intramolecular rearrangement after nucleophilic substitution, resulting in yellow fluorescence. Thus the probe can distinguish Cys/Hcy and GSH. Subsequently, only SO2 could quench red fluorescence by adding CC of benzopyrylium. The probe also could localize well in mitochondria by oxonium ion for all kinds of cells. The probe not only could detect above sulfur-containing active substances of intracellular and extracellular but also monitor the level of them under oxidative stress and apoptosis process in living cells and zebrafish. 相似文献
992.
In this study, we electroplated Co and Cu on nano-spiked silicon substrates that were treated with femtosecond laser irradiations. With energy-dispersive X-ray (EDX) analysis by a scanning electron microscope (SEM), it was found that both Co and Cu are primarily coated on the spike surfaces without changing the morphology of the nanospikes. We also found that nanoscale bridges were formed, connecting the Co-coated silicon spikes. The formation of these bridges was studied and optimized through a series of time-controlled electroplating and oxidizing processes. The bridges are related to the oxidation of Co in the air. When it is irradiated with visible light, this special structure has shown a capability of interactions with carbon monoxide and carbon dioxide molecules. The electroplated cobalt may be used for gas sensors. 相似文献
993.
Renewable electricity-driven reduction of CO2 into value-added chemicals has been recognized as a promising sustainable energy conversion method to achieve carbon-neutrality. Although Sn-based catalysts show excellent selectivity towards CO and HCOOH in CO2 reduction, the reaction activity, i. e. current density, remains quite low (<100 mA cm−2). Herein, a hierarchical bimetallic electrocatalyst consisting of Cu foam-supported bundle-like structure and thin amorphous SnO layer was fabricated for efficient electroreduction of CO2 to C1 products (CO and HCOOH). The hierarchical structure ensured higher large electrochemically active surface area, while the thin amorphous SnO layer could efficiently adsorb CO2, and stabilize the *CO2− intermediate formed in the rate-determining step, thereby boosting the reaction activity of CO2 reduction. As a result, an unprecedented partial current density of 128.6 mA cm−2 was achieved for C1 products at −1.4 V vs. RHE with a Faradaic efficiency of 79.2 % in an H-type cell. The strategy of integrating optimized structure with active site here may be beneficial to other related energy conversion systems. 相似文献
994.
Tianhong Wang Youbin Peng Guanlin Li Yicong Luo Yong Ye Dr. Xiaohong Huo Prof. Wanbin Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(40):10255-10260
3,3-Disubstituted oxindoles bearing quaternary and tertiary stereogenic centers are privileged structural motifs, which widely exist in pharmaceutical and natural products. Herein, a highly regio-, enantio-, and diastereoselective allylic alkylation of 3-alkyl oxindoles through synergistic iridium and copper catalysis is described, which provides a series of 3,3-disubstituted oxindole derivatives containing adjacent quaternary and tertiary stereogenic centers in excellent yields, enantiomeric excess, and diastereomeric ratio (for 30 examples, up to 97 % yield, >99 % ee, and >20 : 1 dr). This method provides exclusive branched selectivity, excellent enantio- and diastereoselectivities, and good functional compatibility. Control experiments suggested that the chiral copper catalyst is required for achieving high reactivities and diastereoselectivities under mild reaction conditions. 相似文献
995.
Jiayong Huang Zhenshuo Yan Peiling Qiu Yufeng Mo Qizhen Cao Qiuhong Li Lini Huo Lichun Zhao 《Molecules (Basel, Switzerland)》2021,26(8)
A new coumarin-acridone fluorescent probe S was designed and synthesized, and the structure was confirmed with 1H/13C NMR spectrometry, single-crystal X-ray diffraction, and high-resolution mass spectrometry. This probe has high sensitivity and selectivity for Fe3+ over other testing metal ions at 420 or 436 nm in acetonitrile–MOPS (3-Morpholinopropanesulfonic Acid) buffer solution (20.0 μM, pH = 6.9, 8:2 (v/v)). Under physiological conditions, the probe displayed satisfying time stability with a detection limit of 1.77 µM. In addition, probe S was successfully used to detect intracellular iron changes through a fluorescence-off mode, and the imaging results of cells and zebrafish confirmed their low cytotoxicity and satisfactory cell membrane permeability, as well as their potential biological applications. 相似文献
996.
Tian-Tian Wang Jing-Yi Liu Rui Guo Jun-Dan An Jian-Zhong Huo Yuan-Yuan Liu Wei Shi Bin Ding 《Molecules (Basel, Switzerland)》2021,26(12)
Metal-organic frameworks (MOFs) have been rapidly developed for their broad applications in many different chemistry and materials fields. In this work, a multi-dentate building block 5-(4-(tetrazol-5-yl)phenyl)-isophthalic acid (H3L) containing tetrazole and carbolxylate moieties was employed for the synthesis of a two-dimensional (2D) lanthanide MOF [La(HL)(DMF)2(NO3)] (DMF = N,N-dimethylformamide) (1) under solvothermal condition. The fluorescent sensing application of 1 was investigated. 1 exhibits high sensitivity recognition for antibiotic nitrofurantoin (Ksv: 3.0 × 103 M−1 and detection limit: 17.0 μM) and amino acid l-tyrosine (Ksv: 1.4 × 104 M−1 and detection limit: 3.6 μM). This work provides a feasible detection platform of 2D MOFs for highly sensitive discrimination of antibiotics and amino acids. 相似文献
997.
Xiaogao Feng & Shengjin Huo 《数学研究》2016,49(1):42-49
In this note, for $k$-quasiconformal mappings of a bounded domain into thecomplex plane, we give an upper bound of Burkholder integral. Moreover, as an applicationwe obtain an upper bound of the $L^p$-integral of $sqrt{J_f}$ and $|Df|$ for certain $K$-quasiconformal mappings. 相似文献
998.
1000.
应用电磁场理论和介质中的麦克斯韦方程组,推导了任意截面微腔的TM模光场分布。并以四极子状微腔截面为例,推导了含有传播常数的本征方程。用Mathematica软件模拟出具有不同变形因子的基模(m=1)和高阶模的光场分布图,得出基模在=45°,135°,225°,315°四个方向光辐射最强,具有“蝴蝶结模式”特征,并且当变形因子值取ε′为0.1~0.15时,该效应表现得更明显;而高阶模(m≥2)时微腔中没有这种光的定向输出现象,在任何变形因子情况下也不能形成稳定的“蝴蝶结模式”,为四极子微腔激光器的设计和制作提供了一定的理论依据。 相似文献