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The compounds in leaf and stem extracts of Astragalus emarginatus Labill., a plant species used in traditional Lebanese medicine, were investigated for antioxidant properties. First, the activity of various extracts was assessed using the Trolox equivalent antioxidant capacity, oxygen radical absorption capacity, and 2,2-diphenyl-1-picryl-hydrazyl-hydrate assays. The extract obtained using 30% ethanol showed the greatest activity. The antioxidant compounds in this extract were screened using a hyphenated high-performance liquid chromatography-2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonate) radical system before being separated by ultra-high-performance liquid chromatography and identified using high-resolution mass spectrometry and ultra-violet-visible diode array detection. Approximately 40 compounds were identified. Hydroxycinnamates (caffeic, ferulic, and p-coumaric acid derivatives) and flavonoids (quercetin, luteolin, apigenin, and isorhamnetin derivatives) were the two main categories of the identified compounds. The active compounds were identified as caffeic acid derivatives and quercetin glycosides. In addition, the catechol moiety was shown to be key to antioxidant activity. This study showed that A. emarginatus Labill. is a source of natural antioxidants, which may explain its medicinal use.

Purpose Methods and materials Results Conclusion Personal information and conflict of interest References, Purpose: Traditional static FDG-PET plays an important role in the identification of epileptic foci, but static standardized uptake value (SUV) is a relative measurement and can be influenced by many factors [1]. Dynamic total-body FDG PET scanning can...

Environmental trace gas monitoring instrument (EMI) onboard GaoFen-5 was launched in May 2018 and has successfully operated on-orbit for more than a year. EMI contains four grating spectrometers, covering wavelengths in the range 240–710 nm with a spectral resolution of 0.3–0.5 nm, and enables one-day global coverage. For EMI on-orbit calibration, two onboard solar diffusers (SD), one surface reflectance aluminum diffuser, and one quartz volume diffuser (QVD) are used to measure solar spectra. The solar spectra are used to perform accurate spectral and radiometric calibrations. EMI on-orbit spectral calibration contains wavelength calibration and instrument spectral response function (ISRF), both of which are the key quantities in trace gas retrievals based on differential optical absorption spectroscopy (DOAS) analysis. The wavelength calibration is performed using the Fraunhofer lines in the solar spectrum, and the ISRF parameters are obtained by fitting high-resolution and EMI-measured solar spectra. Based on the known solar irradiation and characteristic of SD, SD radiance can be calculated and is used for EMI on-orbit radiometric calibration. The radiometric calibration also determines the absolute Earth reflectance spectra that are used as inputs for atmospheric retrieval algorithms. For EMI on-orbit radiometric monitoring, aluminum diffuser is used as reference SD to monitor QVD degradation. An internal white light source is used to detect pixel performance and monitor radiometric throughput.

Ground-based two-dimensional (2D) Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements of nitrogen dioxide (NO2) were collected continuously from June 2015 to May 2016 in Hefei, China. The spatial distribution of NO2 concentrations showed that more air pollution was present in eastern and southeastern direction from the study site, and these areas were located in the center of the city and economic developing zone. The seasonal variations of NO2 concentrations were distinct, and the highest levels were detected in winter, while the lowest levels were detected in summer. The mean concentration of NO2 during the heating season (November–March of the following year) was 6.56 ppbv, while that during the non-heating season (April–October) was 4 ppbv. The highest concentrations of NO2, carbon monoxide (CO), and PM2.5 were all observed during the heating season. The results from the potential source contribution function (PSCF) analysis suggested that NO2 pollution in the summer was caused primarily by long-range transport from the east, while that in winter showed significant local influences. By combining the analyses of meteorological trajectory pressure profiles and aerosol optical depths (AODs), the sources of NO2 during the heating season were found to be mainly local emissions, while those during the non-heating season were mainly from long-range transportation.

The environmental trace gas monitoring instrument (EMI) is a space-borne imaging spectrometer onboard GaoFen-5, which was launched in May 2018, covering wavelengths in the range of 240–710 nm to measure NO2, O3, HCHO, and SO2. An advanced EMI-2 instrument with a higher spatial resolution and sufficient signal-to-noise is currently planned for launch on the GaoFen-5(02) satellite in 2021. The EMI-2 instrument bidirectional scattering distribution function (BSDF) is obtained from the absolute irradiance and radiance calibration on-ground. Based on EMI-2 earth and sun optical paths, the key factors of BSDF parameters are introduced. An NIST-calibrated 1000 W FEL quartz tungsten halogen lamp and a 2D turntable are adopted for the absolute irradiance calibration. A large aperture integrating sphere system is used for the absolute radiance calibration. Based on absolute irradiance and radiance calibration functions, the BSDF parameters are obtained, with accuracy of 4.9% for UV1, 4.3% for UV2, 4.1% for VIS1, and 4.2% for VIS2. The on-ground measurement results show that the reflectance spectrum can be calculated from BSDF parameters. On-orbit application of the EMI-2 instrument BSDF are also discussed.

The Environmental trace gas Monitoring Instrument (EMI) onboard the Chinese high-resolution remote sensing satellite GaoFen-5 is an ultraviolet-visible imaging spectrometer, aiming to quantify the global distribution of tropospheric and stratospheric trace gases and planned to be launched in spring 2018. The preflight calibration phase is essential to characterize the properties and performance of the EMI in order to provide information for data processing and trace gas retrievals. In this paper, we present the first EMI measurement of nitrogen dioxide (NO 2 ) from a gas absorption cell using scattered sunlight as the light source by the differential optical absorption spectroscopy technique. The retrieved NO 2 column densities in the UV and Vis wavelength ranges are consistent with the column density in the gas cell calculated from the NO 2 mixing ratio and the length of the gas cell. Furthermore, the differences of the retrieved NO 2 column densities among the adjoining spatial rows of the detector are less than 3%. This variation is similar to the well-known “stripes-pattern” of the Ozone Monitoring Instrument and is probably caused by remaining systematic effects like a nonperfect description of the individual instrument functions. Finally, the signal-to-noise ratios of EMI in-orbit measurements of NO 2 are estimated on the basis of on-ground scattered sunlight measurements and radiative transfer model simulations. Based on our results, we conclude that the EMI is capable of measuring the global distribution of the NO 2 column with the retrieval precision and accuracy better than 3% for the tested wavelength ranges and viewing angles.

In this study, a response surface methodology (RSM) model was used to analyze and optimize the factors affecting copper leaching efficiency in a copper oxide ammonia-ammonium (AA) system based on the parameters of AA concentration (ammonium hydroxide and ammonium bicarbonate matched with 1: 1), leaching time, grinding fineness, liquid-solid ratio, and temperature. The RSM analysis showed that five individual variables had a significant influence and that the interaction between AA concentration and leaching time had the most significant influence on leaching efficiency. In order to improve the estimation accuracy of the copper leaching efficiency, a model consisting of a genetic algorithm and a back propagation neural network (GA-BPNN) was used to optimize the operation index. A back propagation feed forward neural network with 3 layers (5–10–1) was applied to predict copper leaching efficiency. The genetic algorithm was applied to analyze the optimal leaching conditions. The results revealed that the GA-BPNN model outperformed the RSM model for predicting and optimizing copper oxide AA leaching. The optimization results of the GA-BPNN resulted in an R2 of 0.99827 and the highest predicted copper leaching efficiency of 79.49% was obtained under the conditions of an AA concentration of 4.78 mol/L, a leaching time of 157 min, a grinding fineness of 86.86% (–74 μm content account), a liquid-solid ratio of 2.87: 1, and a temperature of 313.17 K. A prediction and optimization method combining RSM and GA-BPNN, as used in this paper, can be further employed as a reliable and accurate method for ore leaching.

International audience; Phospholipids from seven egg types were purified (purity > 96%) by solid-phase extraction cartridges, and subsequently identified and quantified by ultra-high-performance liquid chromatography-electrospray ionization-quadrupole-time of flight-mass spectrometry (UHPLC-ESI-Q-TOF-MS). 10 phospholipid classes were detected and 93 molecular species were characterized. Principal component analysis (PCA) showed that molecular species and concentration of phospholipids in pigeon and hen egg yolks had significant difference with other egg types. Hierarchical cluster analysis further indicated that the phospholipid profiles of pigeon egg yolk were closest to hen egg yolk, following quail, duck, ostrich, emu and goose egg yolks. The quantification of several representative molecular species can be considered to be most responsible for the discrimination among egg yolks phospholipids, for example, SM(d18:1/16:0) in goose egg yolk and PC(16:0/20:4) in duck egg yolk. This study provides a basis for better understanding phospholipid profiles of egg yolks and better evaluating the nutritional value of eggs.

The space-borne Environment Monitoring Instrument detects the Earth's surface radiation from ultraviolet to visible band, and it could be used to inverse the trace gas concentrations of target area. To obtain the 1b radiation data products, raw measurement data (level 0 data) should be corrected and modulated. Based on CCD detectors and payload’s characteristics, the electronic correction processing flow and data correction algorithm are proposed, and dark current, electronic offset, Smear and PRNU are also corrected. By using this algorithm, the ground level 0 test data are corrected. The result shows that the corrected data can improve the accuracy of the data; it can be used to process the data which are measured in orbit observation; it strongly guarantees the formation of further level 2 data products.

A space-borne differential optical absorption spectrometer was designed on the basis of a four channel Offer imaging spectrometer with a convex grating.It could acquire high accuracy radiation scattered by earth surfaces or air in a nadir push-broom mode,and could quantitatively obtain the trace gas distribution based on the "fingerprint" absorption of the trace gas at different spectral information and the differential optical absorption spectrum algorithm.According to the characteristics of large field,wide wavelength range,high spatial and spectral resolution of the spectrometer,the corresponding methods of spectral calibration and radiometric calibration were presented,and a calibration system was built.Then the spectral and radiometric calibrations of the spectrometer were realized,and the calibration uncertainty was analyzed.Experimental results show that spectral calibration uncertainty of the instrument is 0.027 nm and the radiation uncertainty is 2.96%.The calibration accuracy meets the given requirements and can provide a foundation for quantitatively inversion of the instrument.

The environmental measuring instrument (EMI) is a nadir-viewing wide-field imaging spectrometer, which adopts spaceborne diffusers in in-flight calibration systems, including an aluminum diffuser and a quartz volume diffuser. Spaceborne diffusers, are the key components of in-flight calibration systems, and are used to introduce sunlight into the EMI. Hemispheric reflectance and bidirectional reflectance distribution function were experimentally measured to analyze spaceborne diffuser performance. Radiation exposure experiments on atomic oxygen, UV, and radiation dose of the spaceborne diffusers were performed at ground level because the EMI works in low Earth orbit space environments. Effects of radiation exposure on spaceborne diffusers were discussed in detail. Protective methods were introduced to reduce the effects of the space environment, and an in-orbit monitoring method was also proposed.