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The nitrate radical (NO 3 ) and dinitrogen pentoxide (N 2 O 5 ) play an important role in the nocturnal atmosphere chemistry. Observations of NO 3 radicals and N 2 O 5 were performed in a semirural ground site at Tai'Zhou in polluted southern China using cavity ring down spectroscopy (CRDS) from 23 May to 15 June 2018. The observed NO 3 and N 2 O 5 concentrations were relatively low, with 1 min average value of 4.4 ± 2.2 and 26.0 ± 35.7 pptV, respectively. The N 2 O 5 uptake coefficient was determined to be from 0.027 to 0.107 based on steady state lifetime method. Fast N 2 O 5 hydrolysis was the largest contributor to the loss of NO 3 and contributed to substantial nitrate formation, with an average value of 14.83 ± 6.01 µg/m 3 . Further analysis shows that the N 2 O 5 heterogeneous reactions dominated the nocturnal NO x loss and the nocturnal NO x loss rate is 0.14 ± 0.02 over this region., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020. Published by Elsevier B.V.)

An inexpensive, compact instrument for sensitive measurement of nocturnal nitrogen oxides NO 3 and N 2 O 5 in ambient air at high time resolution has been described. The instrument measures NO 3 and N 2 O 5 which is converted into the NO 3 radical through thermal decomposition by optical extinction using a diode laser at 662.08 nm in two separate detection channels. The minimum detection limits (1σ) for the NO 3 radical and N 2 O 5 are estimated to be 2.3 pptv and 3.1 pptv in an average time of 2.5 s, with the accessible effective absorption path length generally exceeding 30 km, which is sufficient for quantifying NO 3 radical and N 2 O 5 concentrations under moderately polluted conditions. The total uncertainties of the NO 3 and N 2 O 5 measurements are 8% and 15% respectively, which are mainly dominated by the uncertainty of NO 3 across section calculated for 353 K in this system. In addition, the dependence of the instrument's sensitivity and accuracy on a variety of conditions was presented in winter of 2016 and in summer of 2017 during two China-UK joint campaigns. Distinct N 2 O 5 vertical profiles were observed at night in winter. The equilibrium among observed NO 2 , NO 3 and N 2 O 5 based on the equilibrium constants during summer time also provides confirmation of the measurement accuracy of the instrument.

Dinitrogen pentoxide (N 2 O 5 ) is one of the basic trace gases which plays a key role in nighttime atmosphere. An intercomparison and validation of different N 2 O 5 measurement methods is important for determining the true accuracy of these methods. Cavity ring down spectroscopy (CRDS) and cavity enhanced absorption spectrometer (CEAS) were used to measure N 2 O 5 at the campus of the University of Chinese Academy of Sciences (UCAS) from February 21, 2016 to March 4, 2016. The detection limits were 1.6ppt (1σ) at 30s intervals for the CEAS instrument and 3.9ppt (1σ) at 10s time resolution for the CRDS instrument respectively. In this study, a comparison of the 1min observations from the two instruments was presented. The two data sets showed a good agreement within their uncertainties, with an absolute shift of 15.6ppt, slope of 0.94 and a correlation coefficient R 2 =0.97. In general, the difference between the CRDS and CEAS instruments for N 2 O 5 measurement can be explained by their combined measurement uncertainties. However, high relative humidity (>60%) and high PM2.5 concentration (>200μg/m 3 ) may contribute to the discrepancies. The excellent agreement between the measurement by the CRDS and CEAS instruments demonstrates the capability of the two instruments for accurately measuring N 2 O 5 with high sensitivity., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Aim: The aim of this study was to investigate the relationship between the expression of neutral endopeptidase (NEP) and dipeptidyl peptidase IV (DPP IV) proteins, and the clinical significance of the two proteins in patients with intrahepatic cholangiocarcinomas (IHCC)., Methods: Expression patterns and subcellular localizations of NEP and DPP IV proteins in 186 primary IHCC and 60 noncancerous liver tissue specimens were detected by immunohistochemistry., Results: Both the expression of NEP and DPP IV proteins in IHCC tissues were significantly higher than those in noncancerous liver tissues (both P<0.001). Of 186 patients with IHCC, 128 (68.82%) highly expressed both NEP and DPP IV proteins. In addition, the coexpression of NEP and DPP IV proteins was significantly associated with advanced tumor stage (P=0.009), positive lymph node metastasis (P=0.016) and distant metastasis (P=0.013), and the presence of recurrence (P=0.027). Moreover, Kaplan-Meier analysis showed that IHCC patients with high NEP expression, high DPP IV expression, and combined overexpression of NEP and DPP IV proteins all had poorer overall survival and early recurrence after surgery. Furthermore, Cox analysis suggested that NEP expression, DPP IV expression, and combined expression of NEP and DPP IV proteins were all independent prognostic markers for overall survival and recurrence-free survival in patients with IHCC., Conclusion: Our data suggest, for the first time, that both the expression of NEP and DPP IV proteins may be upregulated in human IHCC tissues and the combined expression of NEP and DPP IV proteins may play important roles in progression and prognosis of patients with IHCC.