Silicon phthalocyanine derivatives 1a and 1b were synthesized and characterized by UV, <sup>1</sup>H-NMR and MS. The photophysical properties of the compounds in DMSO were investigated. The maximum absorpt...Silicon phthalocyanine derivatives 1a and 1b were synthesized and characterized by UV, <sup>1</sup>H-NMR and MS. The photophysical properties of the compounds in DMSO were investigated. The maximum absorption peaks of compounds 1a and 1b at the Q-band are 681 nm. With ZnPc (Φ<sub>F</sub> = 0.20, Φ<sub>Δ</sub> = 0.67) as a reference, the fluorescence quantum yield (Φ<sub>F</sub>) of 1a and 1b are 0.20 and 0.31 respectively, and the singlet oxygen quantum yield (Φ<sub>Δ</sub>) are 0.66 and 0.59 respectively. The DNA-photocleavage activities of compounds 1a and 1b were studied by gel electrophoresis. Compounds 1a and 1b possess good photocleavage activity to pBR322 DNA. The results demonstrate that compounds 1a and 1b are potential photosensitizers for tumor therapy.展开更多
Current atmospheric quality models usually underestimate the level of ambient secondary organic aerosol(SOA), one of the possible reasons is that the precursors at different concentrations may undergo different oxidat...Current atmospheric quality models usually underestimate the level of ambient secondary organic aerosol(SOA), one of the possible reasons is that the precursors at different concentrations may undergo different oxidation processes and further affect SOA formation. Therefore, there is a need to perform more chamber studies to disclose the influence. In this work, SOA formation over a wide range of initial precursor concentrations(tens of ppb to hundreds of ppb levels) was investigated in a 30 m3 indoor smog chamber,and mainly through the analysis of multiple generations of VOCs detected from HR-To FPTRMS to expound the difference in the oxidation process between low and high precursor concentrations. Compared to high initial concentrations, gas-phase intermediates formed at low concentrations had a higher intensity by about one order of magnitude, and the lowvolatility compounds also had a higher formation potential due to the competition between semi-volatile intermediates and precursors with oxidants. In addition, the formed SOA was more oxidized with higher f44 value(0.14 ± 0.02) and more relevant to real atmosphere than that formed at high concentrations. This work should help to deeply understand SOA formation and improve the performance of air quality models for SOA simulation.展开更多
The dithiothreitol(DTT)assay is the most commonly used method to quantify the oxidative potential of fine particles.However,the reported DTT decay rates of carbon black(CB)materials vary greatly among different resear...The dithiothreitol(DTT)assay is the most commonly used method to quantify the oxidative potential of fine particles.However,the reported DTT decay rates of carbon black(CB)materials vary greatly among different researchers.This might have resulted from either the intrinsic toxicity of CB or the unsuitability of the DTT assay protocol for CB particles.In the current study,the protocol of the DTT assay for CB materials has been carefully evaluated.It was found that the dispersion degree of CB particles in water has a great influence on the DTT decay rate of CB materials.For CB particles(special black 4A(SB4A)and Printex U)and single-walled carbon nanotube tube(SWCNT),the DTT decay rate after sonication for 10 min became 4.2,4.6 and 1.7 times higher than that without sonication.The rate continued to grow as a function of ultrasound time up to 30 min of sonication.Although the concentration of soluble transition metals and surface oxygen-containing species such as carbonyls increased slightly with sonication,they had no significant effects on the measured DTT activity,while the increase in the dispersion degree of aggregates was found to play a vital role in the observed enhancement of the DTT decay rates for different CB materials.Based on our results,30 min of sonication is recommended for sample dispersion when measuring the DTT decay rate of CB materials.展开更多
文摘Silicon phthalocyanine derivatives 1a and 1b were synthesized and characterized by UV, <sup>1</sup>H-NMR and MS. The photophysical properties of the compounds in DMSO were investigated. The maximum absorption peaks of compounds 1a and 1b at the Q-band are 681 nm. With ZnPc (Φ<sub>F</sub> = 0.20, Φ<sub>Δ</sub> = 0.67) as a reference, the fluorescence quantum yield (Φ<sub>F</sub>) of 1a and 1b are 0.20 and 0.31 respectively, and the singlet oxygen quantum yield (Φ<sub>Δ</sub>) are 0.66 and 0.59 respectively. The DNA-photocleavage activities of compounds 1a and 1b were studied by gel electrophoresis. Compounds 1a and 1b possess good photocleavage activity to pBR322 DNA. The results demonstrate that compounds 1a and 1b are potential photosensitizers for tumor therapy.
基金supported by the National Key R&D Program of China(No.2016YFC0202700)the National Natural Science Foundation of China(No.91543109 and 41877306)+1 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(Nos.XDB05040100,XDB05010300)the Youth Innovation Promotion Association,CAS(No.2018060)
文摘Current atmospheric quality models usually underestimate the level of ambient secondary organic aerosol(SOA), one of the possible reasons is that the precursors at different concentrations may undergo different oxidation processes and further affect SOA formation. Therefore, there is a need to perform more chamber studies to disclose the influence. In this work, SOA formation over a wide range of initial precursor concentrations(tens of ppb to hundreds of ppb levels) was investigated in a 30 m3 indoor smog chamber,and mainly through the analysis of multiple generations of VOCs detected from HR-To FPTRMS to expound the difference in the oxidation process between low and high precursor concentrations. Compared to high initial concentrations, gas-phase intermediates formed at low concentrations had a higher intensity by about one order of magnitude, and the lowvolatility compounds also had a higher formation potential due to the competition between semi-volatile intermediates and precursors with oxidants. In addition, the formed SOA was more oxidized with higher f44 value(0.14 ± 0.02) and more relevant to real atmosphere than that formed at high concentrations. This work should help to deeply understand SOA formation and improve the performance of air quality models for SOA simulation.
基金financially supported by the National Natural Science Foundation of China (Nos. 91543109 and 41877306)the Fundamental Research Funds for the Central Universities (No. PT1907)Beijing University of Chemical Technology for financial support
文摘The dithiothreitol(DTT)assay is the most commonly used method to quantify the oxidative potential of fine particles.However,the reported DTT decay rates of carbon black(CB)materials vary greatly among different researchers.This might have resulted from either the intrinsic toxicity of CB or the unsuitability of the DTT assay protocol for CB particles.In the current study,the protocol of the DTT assay for CB materials has been carefully evaluated.It was found that the dispersion degree of CB particles in water has a great influence on the DTT decay rate of CB materials.For CB particles(special black 4A(SB4A)and Printex U)and single-walled carbon nanotube tube(SWCNT),the DTT decay rate after sonication for 10 min became 4.2,4.6 and 1.7 times higher than that without sonication.The rate continued to grow as a function of ultrasound time up to 30 min of sonication.Although the concentration of soluble transition metals and surface oxygen-containing species such as carbonyls increased slightly with sonication,they had no significant effects on the measured DTT activity,while the increase in the dispersion degree of aggregates was found to play a vital role in the observed enhancement of the DTT decay rates for different CB materials.Based on our results,30 min of sonication is recommended for sample dispersion when measuring the DTT decay rate of CB materials.
