Wu, Cuiyan
Xu, Hai
Li, Yaqian
Xie, Ruihua
Li, Peijuan
Pang, Xiao
Zhou, Zile
Li, Haitao
Zhang, Youyu
Hydrazine (N2H4) is widely used in industry but also very toxic. Herein, we describe the preparation of a "naked-eye" colorimetric and ratiometric fluorescent probe (DH), bearing alpha,beta-unsaturation carbonyl group as a recognition site, and employ it for the excited-state intramolecular proton transfer based (ESIPT-based) detection of N2H4. The probe can detect N2H4 by colorimetric and ratiometric fluorescence dual signals with high sensitivity and selectivity; the detection limit of N2H4 was 0.063 mu M (2.01 ppb), which was far below the safety level (10 ppb) stated by the U.S. Environmental Protection Agency (EPA). It enables "naked-eye" detection for hydrazine determination in aqueous solution. More importantly, we successfully applied DH to detect N2H4 in real water samples, indicating its potential utility for N2H4 sensing in environmental samples.
Li, Yaqian
Xie, Ruihua
Pang, Xiao
Zhou, Zile
Xu, Hai
Gu, Biao
Wu, Cuiyan
Li, Haitao
Zhang, Youyu
Alkaline phosphatase (ALP) is a non-specific phosphate monoesterase and often regarded as an important biomarker of hypothyroidism and hepatobiliary diseases in medical diagnosis. In-situ detection of endogenous ALP and exploration of the distribution of ALP in cells are of great importance for the diagnosis of diseases associated with ALP. In this work, we designed and synthesized an aggregation-induced emission (AIE) fluorescent probe, (E)-2-(((9H-fluoren-9-ylidene) hydrazono)methyl)phenyl dihydrogen phosphate (FAS-P), that can respond to ALP with a remarkable large Stokes shift ( > 200 nm) based on excited state intramolecular proton transfer (ESIPT) mechanism. The probe FAS-P has high selectivity and sensitivity to the detection of ALP. And there is a linear relationship between the fluorescence intensity of FAS-P and ALP activity in the range of 1-100 U L-1, the limit of detection (LOD) is as low as 0.6 U L-1. More importantly, we successfully applied FAS-P to detect ALP in living cells and the monitoring of ALP in real time.
Electrodialysis (ED) technique is a typical and promising membrane process, for applications like water treatment and ion separation. Especially, the separation between monovalent and multivalent cations is a current central issue in many industries and academic researches. Herein, a series of novel cation exchange membranes were prepared from quaternized polyaniline modified sulfonated polyphenyl sulfone (SPPSU) by in-situ polymerization-deposited polyaniline followed by quaternizing with methyl iodide. Restricted divalent cation penetration and regulated monovalent cation transport were achieved by elevating the kinetic effect of electrostatic repulsion and narrowing water channel. Importantly, positive charge density of modification layer could be adjusted by controlling the degree of quaternization, which was accompanied by the change of water channel. When evaluated in a simulated mixed salt system (Mg2+/Na+ and Mg2+/Li+), the optimal quaternized polyaniline membrane exhibited a higher perm-selectivity (P-Mg(Na)=3D4.1, P-Mg(Li)=3D1.75) than initial polyaniline modified cation exchange membrane (P-Mg(Na)=3D0.8, P-Mg(Li)=3D0.75), and commercial monovalent-selective cations exchange membrane CIMS (P-Mg(Na)=3D3.56, P-Mg(Li)=3D1.11). This presented strategy is straightforward and effective, demonstrating the effect of surface positive charge layer on perm-selectivity.
Lei, Peng
Pang, Xiao
Feng, Xiaohai
Li, Sha
Chi, Bo
Wang, Rui
Xu, Zongqi
Xu, Hong
Poly-gamma-glutamic acid (gamma-PGA) is a microbe-secreted isopeptide that has been shown to promote growth and enhance stress tolerance in crops. However, its site of action and downstream signaling pathways are still unknown. In this study, we investigated.-PGA-induced tolerance to salt and cold stresses in Brassica napus L. seedlings. Fluorescent labeling of gamma-PGA was used to locate the site of its activity in root protoplasts. The relationship between.-PGA-induced stress tolerance and two signal molecules, H2O2 and Ca2+, as well as the gamma-PGA-elicited signaling pathway at the whole plant level, were explored. Fluorescent labeling showed that gamma-PGA did not enter the cytoplasm but instead attached to the surface of root protoplasm. Here, it triggered a burst of H2O2 in roots by enhancing the transcription of RbohD and RbohF, and the elicited H2O2 further activated an influx of Ca2+ into root cells. Ca2+ signaling was transmitted via the stem from roots to leaves, where it elicited a fresh burst of H2O2, thus promoting plant growth and enhancing stress tolerance. On the basis of these observation, we propose that.-PGA mediates stress tolerance in Brassica napus seedlings by activating an H2O2 burst and subsequent crosstalk between H2O2 and Ca2+ signaling.
A rule-based event handling model is proposed in the paper, which has a hierarchical architecture with four-layers: resource layer, knowledge layer, business layer and representation layer. This model is aimed at distributed information integrating and service scheduling for event handling through rule in knowledge layer. Detail work on knowledge layer is explored, which includes definition of formal business rule, reference to resources in a rule, as well as design and implementation of the rule system. A unified urgent event call-in disposition of city joint emergency response systems is taking as an example of rule-based information integrating and service scheduling.
Huang, Zhen
Wu, Cuiyan
Li, Yaqian
Zhou, Zile
Xie, Ruihua
Pang, Xiao
Xu, Hai
Li, Haitao
Zhang, Youyu
Serum cysteine (Cys) level is correlated with many diseases. Therefore, it is very important to detect the concentration of serum cysteine with high sensitivity and accuracy. In this study, a turn-on fluorescent and colorimetric probe, (E)-2-(2-(4-formylstyryl)-4H-chromen-4-ylidene)malononitrile, termed as probe 1, was designed and synthesized for the detection of Cys in serum. Upon the addition of Cys, a remarkable enhancement in the fluorescence feature at 440 nm and a significant colour change of the probe solution were observed. Under optimal conditions, the probe enables quantitative analysis of Cys with high sensitivity. Moreover, the detection limit of Cys was calculated as 63 nM. The results showed that the fluorescence response of probe 1 to cysteine was highly selective when homocysteine (Hcy), glutathione (GSH) and other natural amino acids coexisted with cysteine under physiological conditions. Furthermore, the probe 1 could be used to accurately and sensitively detect cysteine in human serum.
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