- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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A colorimetric and ratiometric fluorescent probe with ultralow detection limit and high selectivity for phosgene sensing
摘要： Phosgene is a kind of colourless and extreme toxic gas that poses a serious threat to public health and safety. A colorimetric and ratiometric fluorescent probe (AC-6ED), with anthracene carboximide as fluorophore and ethylenediamine group as recognition moiety has been developed for phosgene detection in solutions and in the gas phase based on the intramolecular charge transfer (ICT) mechanism. The AC-6ED traps phosgene molecule via intramolecular cyclization reaction to afford color and fluorescence emission change. The AC-6ED features low detection limit (0.09 nM), fast response (< 20 s), remarkable colorimetric and ratiometric signal, excellent selectivity for phosgene over other interference analytes such as nerve agent mimics, various acyl chlorides and analogues. The AC-6ED loaded TLC plate can serve as a highly selective tool for phosgene sensing in the gas phase below health risk concentrations in a fast, portable, visible, and highly sensitive manner.
关键词： ratiometric fluorescence,phosgene,fluorescent probe,anthracene carboximide
更新于2025-09-04 15:30:14
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Visual colorimetric and fluorescence turn-on probe for Cu(II) ion based on coordination and catalyzed oxidative cyclization of ortho amino azobenzene
摘要： 2,2′-diaminoazobenzene (L1), a visual colorimetric and fluorescence turn-on detection probe for Cu2+ ion, has been discovered successfully. The yellow L1 solution changed into light-purple solution rapidly with dropping of Cu2+ ion observed by the naked eyes, for the formation of 1:1 complex of L1 and Cu2+ ion calculated by Job-plot method. Non-emissive L1 transformed into 2-(2-aminophenyl) benzotriazole (L1-BTA) with strong fluorescence at the peak around 475 nm, owing to the Cu2+ catalyzed oxidative cyclization of L1, accompanied by the fluorescence intensity gradually increasing within 20 min. And L1 was applied for quantitative detection of Cu2+ with good linear relationship between its UV absorbance and Cu2+ concentration, and exhibited high fluorescence selectivity toward Cu2+ over other metal ions (Fe3+, Zn2+, Cd2+, Co2+, Ni2+, Mn2+, Na+, Al3+ and Ca2+) in EtOH solution.
关键词： Cu(II) ion,Oxidative cyclization,Fluorescence probe,Coordination,Amino azobenzene
更新于2025-09-04 15:30:14
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[IEEE 2018 24th International Conference on Pattern Recognition (ICPR) - Beijing, China (2018.8.20-2018.8.24)] 2018 24th International Conference on Pattern Recognition (ICPR) - Confidence-Driven Network for Point-to-Set Matching
摘要： The goal of point-to-set matching is to match a single image with a set of images from a subject. Within an image set, different images contain various levels of discriminative information and thus should contribute differently to the results. However, the discriminative level is not accessible directly. To this end, we propose a confidence driven network to perform point-to-set matching. The proposed system comprises a feature extraction network (FEN) and a performance prediction network (PPN). Given an input image, the FEN generates a template, while the PPN generates a confidence score which measures the discriminative level of the template. At matching time, the template is used to compute a point-to-point similarity. The similarity scores from different samples in the set are integrated at a score level, weighted by the predicted confidence scores. Extensive multi-probe face recognition experiments on the IJB-A and UHDB-31 datasets demonstrate performance improvements over state of the art algorithms.
关键词： feature extraction network,performance prediction network,multi-probe face recognition,confidence driven network,point-to-set matching
更新于2025-09-04 15:30:14
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Comparison of on-wafer TRL calibration to ISS SOLT calibration with open-short de-embedding up to 500 GHz
摘要： Sub-mm circuit design requires accurate on-wafer characterization of passive and active devices. In industry, characterization of these devices is often performed with off-wafer SOLT calibration. In this work, validity of this characterization procedure above 110 GHz is investigated by an exhaustive study of on-wafer and alumina off-wafer calibration using measurement and electromagnetic (EM) simulation up to 500 GHz. The EM simulation is performed at two different levels, first at the intrinsic level of the devices under test for reference and afterward up to the probe level to simulate different standards used in the off-wafer calibration or in the on-wafer calibration in presence of the probe. Further, EM simulation data is calibrated with the same procedures and tools that is used in the measurement; therefore, it includes the probe-to-substrate coupling. In addition, precise EM model of a commercial impedance standard substrate (ISS) is developed and used to perform the SOLT calibration. A good agreement is observed between measurement and EM modelling for the off-wafer calibration as well as for the on-wafer calibration. Results clearly highlights a limitation of alumina off-wafer methodology above 200 GHz for characterization of Silicon based technologies. Finally a discussion is given on the pros and cons of the off-wafer and on-wafer methodologies.
关键词： probe station,calibration,S-parameter measurement,TRL,THz,SiGe HBT,on-wafer,500 GHz,SOLT
更新于2025-09-04 15:30:14
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A novel OFF-ON-OFF fluorescence probe based on coumarin for Al3+ and F? detection and bioimaging in living cells
摘要： A novel fluorescence probe L2 based on coumarin has been designed and synthesized. The probe L2 can be used for relay recognition of metal ions Al3+ and anion F? in the aqueous HEPES buffer (0.05 M, pH=7.4), and build a OFF-ON-OFF detection system. The probe showed high selectivity and sensitivity to target ions in the process of relay recognition, and the corresponding detection limit could be as low as 0.014 μM (Al3+) and 0.03 μM (F?). Besides, the geometry optimizations of probe L2 and [L2+Al3+] complex were carried out using the Gaussian 16 program based on DFT, and the identification mechanism of the probe was also discussed by the mass spectrometry and theoretical calculations. Moreover, the probe have also been successfully applied to detection of target ions in living cells.
关键词： Al3+,coumarin,Fluorescence probe,cell imaging,F?
更新于2025-09-04 15:30:14
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Deep-red fluorogenic probe for rapid detection of nitric oxide in Parkinson’s disease models
摘要： Nitric oxide (NO), as one of important gaseous signaling molecule in human body, has been associated with a variety of physiologic processes. However, excessive production of NO has been profoundly implicated in the pathogenesis of neurodegenerative disorders in particular, Parkinson's disease (PD). Therefore, accurate and facile detection of NO is of great significance for investigating its functions in PD, and the subsequent diagnosis and/or treatment. Herein, we developed a deep-red fluorogenic probe (BT-NH), with high sensitivity and good selectivity to detect NO, which was successfully used to visualize exogenous/endogenous NO level in living cells, and further applied to in vitro and in vivo PD models.
关键词： Parkinson’s disease,Drosophila,live cell imaging,nitric oxide,fluorogenic probe
更新于2025-09-04 15:30:14
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A Two-Photon Ratiometric Probe for Hydrogen Polysulfide (H2Sn): Increase in Mitochondrial H2Sn Production in a Parkinson’s Disease Model
摘要： Hydrogen polysulfide (H2Sn, n>1), which is primarily generated during the crosstalk between H2S and reactive species (ROS and RNS), is receiving increasing attention in biochemical research. H2Sn is mostly generated in the mitochondria, and abnormal mitochondrial function and oxidative stress are directly related to many disorders including Parkinson's disease (PD). We now report a two-photon fluorescent probe (SPS-M1) for in situ detection of H2Sn and its application to a PD model to account the H2Sn levels. The probe exhibited selective and fast response to H2Sn along with a marked blue-to-green color change. SPS-M1 is sensitive enough to quantitative detection of endogenous H2Sn content in mitochondria using two-photon microscopy (TPM). Ratiometric TPM imaging of live neurons and brain slices using SPS-M1 revealed that H2Sn production is increased to a greater extent in the A53T α-synuclein (α-syn) overexpressing model than in the wild-type control. These findings suggest that the interactions of H2S and the increased ROS caused by α-syn overexpression may generate more H2Sn. By employing our recently published TP probe for mitochondrial H2S, we also found the relationship between the H2Sn and H2S; increased H2Sn and decreased H2S levels, indicating that H2S and H2Sn may play a significant role in the pathogenesis of PD. This result may be useful to biomedical studies, including PD.
关键词： two-photon microscopy,fluorescent probe,Parkinson’s disease,Hydrogen polysulfide,mitochondria
更新于2025-09-04 15:30:14
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Synthesis of Highly Sensitive and Selective Probe for Fluorescent Detection of Chromium(III)
摘要： A new fluorescent probe capable of sensing Cr3+ has been synthesized. Complexing with Cr3+ triggers the formation of a highly fluorescent ring-open form which is pink in colour. The probe shows extremely high fluorescence enhancement upon complexation with Cr3+ and it can be used as a ‘naked eye’ probe.
关键词： Fluorescent,Chromium(III),Rhodamine B,Probe
更新于2025-09-04 15:30:14
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A molecular design strategy to construct the near-infrared fluorescent probe for selectively sensing human cytochrome P450 2J2
摘要： Cytochrome P450 2J2 (CYP2J2), a key enzyme responsible for oxidative metabolism of various xenobiotics and endogenous compounds, participates in a diverse array of physiological and pathological processes in humans. Its biological role in tumorigenesis and cancer diagnosis remains poorly understood, owing to the lack of molecular tools suitable for real-time monitoring CYP2J2 in complex biological systems. Using molecular design principles we were able to modify the distance between the catalytic unit and metabolic recognition moiety, allowing us to develop a CYP2J2 selective fluorescent probe using a near-infrared fluorophore (E)-2-(2-(6-hydroxy-2, 3-dihydro-1H-xanthen-4-yl)vinyl)-3,3-dimethyl-1-propyl-3H-indol-1-ium iodide (HXPI). To improve the reactivity and isoform specificity, a self-immolative linker was introduced to the HXPI derivatives in order to better fit the narrow substrate channel of CYP2J2, the modification effectively shortened the spatial distance between the metabolic moiety (O-alkyl group) and catalytic center of CYP2J2. After screening a panel of O-alkylated HXPI derivatives, BnXPI displayed the best combination of specificity, sensitivity and applicability for detecting CYP2J2 in vitro and in vivo. Upon O-demethylation by CYP2J2, a self-immolative reaction occurred spontaneously via 1,6-elimination of p-hydroxybenzyl resulting in the release of HXPI. Allowing BnXPI to be successfully used to monitor CYP2J2 activity in real-time for various living systems including cells, tumor tissues, and tumor-bearing animals. In summary, our practical strategy could help the development of a highly specific and broadly applicable tool for monitoring CYP2J2, which offers great promise for exploring the biological functions of CYP2J2 in tumorigenesis.
关键词： Cytochrome P450 2J2,near-infrared fluorescent probe,real-time monitoring,molecular design,CYP2J2,tumorigenesis
更新于2025-09-04 15:30:14
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Fano resonance between coherent acoustic phonon oscillations and electronic states near the bandgap of photoexcited GaAs
摘要： Impulsive photo-excitation of solids results in a travelling strain pulse which manifests itself as coherent acoustic phonon oscillations. These oscillations have been extensively studied using time-resolved pump-probe spectroscopy. In the present work, we report the generation of extremely long-lived, coherent longitudinal acoustic phonon oscillations in intrinsic GaAs (100), with clear and unambiguous evidence of Fano interference between these oscillations and the continuum of electronic states close to the bandgap. Fano resonance is a widespread phenomenon observed in atomic systems and condensed media that arises from quantum interference between a continuum of quantum states and a discrete quantum state. Among other techniques, Fano resonance has been investigated with respect to optical phonons studied with Raman Spectroscopy. In the present work, we investigate Fano resonance in coherent phonon oscillations generated without the aid of any capping layer, dopants or substrate/interface effects. Since Fano resonance is sensitive to changes in electronic structure, doping and defects, these observations are important to the field of picosecond ultrasonics which is used for non-destructive depth profiling of solids and for carrier diffusion studies.
关键词： GaAs,coherent acoustic phonon oscillations,Fano resonance,quantum interference,pump-probe spectroscopy
更新于2025-09-04 15:30:14