Characteristics of optical properties of DOM and nutrients in rainwater of different ecological areas of a large reservoir in China.

Numerous studies have focused on the spectral characteristics and seasonal variations of dissolved organic matter (DOM) in rainwater. However, the relationship between the optical indices of DOM and nutrients in rainwater from different ecological areas of large reservoirs is poorly understood. A one-year monitoring study was conducted between March 2019 and February 2020 in the Danjiangkou Reservoir in Henan Province, China, to compare the composition, spectral characteristic parameters, and relationship between the optical indices of DOM and nutrients in rainwater under different ecological environments. The study showed that the average value of a300 in all samples was 5.29 ± 2.16 m-1 and showed a seasonal trend of higher in spring and winter and lower in summer and autumn as well as a regional difference of agricultural area > urban area > reservoir area. A three-dimensional fluorescence with parallel factor analysis (EEM-PARAFAC) revealed four components of the rainwater: C1 and C2 as UV humic-like substances, and C3 and C4 as protein-like substances. The protein-like components of rainwater from agricultural areas had a high fluorescence intensity, whereas the UV humic-like components of rainfall from urban and reservoir areas had a high fluorescence intensity. Analysis of the fluorescence indices showed that rainwater DOM humification was low and had a strong endogenous character in the Danjiangkou Reservoir. The redundancy analysis revealed that NO3--N, DTN, and SO42- mainly influenced the DOM optical indices of rainwater in urban areas, EC, DTN, and DOC had the highest interpretation of the DOM optical indices of rainwater in agricultural areas, and SO42-, DOC, and DTN had the highest interpretation of the DOM optical indices of rainwater in the reservoir. Overall, understanding the characteristics of rainfall DOM fluorescence and the relationships with nutrients in different ecological regions provides important information for comprehending biogeochemical processes in reservoirs.

Characteristics of dissolved N2O and indirect N2O emission factor in the groundwater of high nitrate leaching areas in northwest China.

Numerous studies have demonstrated high concentrations of dissolved N2O and indirect N2O emission factors in groundwater affected by agriculture. However, the characteristics of seasonal and vertical dimensional difference in groundwater in high nitrate leaching areas are relatively lacking. We monitored the concentrations of dissolved and wellhead N2O of 23 groundwater wells over a one year period to understand the seasonal characteristics of dissolved and wellhead N2O concentrations and indirect N2O emission factors (EF5) of the shallow and deep groundwater in a high nitrogen leaching area and analyze the reasons for their differences. The mean dissolved N2O concentration in groundwater was 9.71 (9.03) µg/L, which was 1.5-fold higher during the wet season relative to the dry season. Furthermore, the leaching of soil N2O caused by rainfall and irrigation could be a pivotal factor affecting seasonal variation in the dissolved N2O. Shallow wells were found to have higher dissolved and wellhead N2O concentrations compared with deep wells in all seasons. The low wellhead N2O concentrations during the dry season were attributed to the seasonal decrease of the groundwater table and dissolved N2O concentrations. We concluded that indirect N2O emission factors did not vary in the vertical dimension but were higher during the wet season than that during the dry season. In addition, the mean indirect N2O emission factor in the groundwater was 0.025 %, which was one order of magnitude below the current IPCC value (0.25 %). Thus, we proposed that such a low indirect N2O emissions factor could imply a low indirect N2O emission potential in groundwater with high dissolved oxygen and nitrogen loads. Our study further indicated that seasonal differences in dissolved N2O concentrations and indirect N2O emission factors should be considered when estimating the potential emissions of dissolved N2O in groundwater.

Dissolved greenhouse gas emissions from agricultural groundwater irrigation in the Guanzhong Basin of China.

While evidence indicates that groundwater is a potential source for greenhouse gas (GHG) emissions, information for such emissions in groundwater used for irrigation is lacking. Based on 23 wells in the mid-western Guanzhong Basin of China, we investigated the dissolved CO2, N2O, and CH4 distributions in groundwater, their relationships with water indicators, and emission fluxes during flood irrigation. We found zero methane, but CO2 and N2O were 30 and 25 times, respectively, supersaturated compared to atmospheric concentrations. Dissolved N2O in groundwater was positively correlated with NO3--N (P = 0.009), while CO2 depended mainly on low pH and high dissolved inorganic carbon. The CO2 and N2O emission fluxes detected in wellheads, especially in shallow wells, implied potential emissions. Flood irrigation experiments showed that 24.55% of dissolved CO2 and 36.81% of dissolved N2O in groundwater was degassed immediately (within 12 min of irrigation) to the atmosphere. Our study demonstrates that direct GHG emissions from groundwater used for agricultural irrigation in the Guanzhong Basin are potentially equivalent to about 2-4% of the GHG emissions from 3 years of fertilizer use on these farmlands, so further research should focus on optimizing irrigation strategies to mitigate GHG emissions.

Quality value transmitting of substance benchmarks in Danggui Buxue Decoction / 中国中药杂志

To clarify the key quality attributes of substance benchmarks in Danggui Buxue Decoction(DBD), this study prepared 21 batches of DBD substance benchmarks, and established two methods for detecting their fingerprints, followed by the identification of peak attribution and similarity range as well as the determination of extract and transfer rate ranges and contents of index components ferulic acid, calycosin-7-O-β-D-glucoside, and astragaloside Ⅳ. The mass fractions and transfer rates of DBD substance benchmarks from different batches were calculated as follows: ferulic acid(index component in Angelicae Sinensis Radix): 0.037%-0.084% and 31.41%-98.88%; astragaloside Ⅳ(index component in Astragali Radix): 0.021%-0.059% and 32.18%-118.57%; calycosin-7-O-β-D-glucoside: 0.002%-0.023% and 11.51%-45.65%, with the extract rate being 18.4%-36.1%. The similarity of fingerprints among 21 batches of DBD substance benchmarks was all higher than 0.9. The quality control method for DBD substance benchmarks was preliminarily established based on the HPLC fingerprint analysis and index component determination, which has provided a basis for the subsequent development of DBD and the quality control of novel related preparations.

Pharmacokinetic behaviors of four constituents in sugar-free Xinnaosu Granules in rat plasma / 中成药

AIM To investigate the pharmacokinetic behaviors of four constituents in sugar-free Xinnaosu Granules in rat plasma.METHODS Rats intragastrically administered with the 0.5％ CMC-Na suspension of this drug (3 g/kg) had their blood collected for the determination of plasma concentration by UHPLC-MS/MS,after which pharmacokinetic parameters were calculated by DAS2.0 software.RESULTS The plasma concentrationtime curves for tanshinone Ⅱ A,salvianolic acid B,ginsenoside Rg1,notoginsenoside R1 accorded with two compartment model,with the t1/2values of (1.68 ±0.56),(4.13 ±0.87),(3.62 ±0.87),(9.77 ±3.12) h,Tmax values of (0.51 ±0.19),(1 ±0),(6 ±0),(4.00 ±1.09) h,Cmax values of (0.42 ±0.08),(0.17 ±0.02),(0.46±0.11),(0.41 ±0.12) mg/L,respectively.CONCLUSION All the four constituents in sugar-free Xinnaosu Granules demonstrate high bioavailabilities.

Screen absorption enhancer for intranasal administration preparations of paeoniflorin based on nasal perfusion method in rats / 中国中药杂志

This experiment was aimed to screen the absorption enhancer for intranasal administration preparations of paeoniflorin. In this study, HPLC method for determination of paeoniflorin in perfusion liquid was established and the improved model of nasal perfusion in rats was used to screen out the species and amounts of absorption enhancer. In order to avoid the influence of the secretion and absorption of nasal cavity on the volume of perfusion fluid, the residual dose was calculated by using the volume correction method. Linear regression was carried out between the logarithm to the percentage of the residual dose and the corresponding time, and the slope of the regression line was exactly the absorption rate constant. Experimental results showed that hydroxypropyl-β-cyclodextrin and water-soluble azone can significantly improve the nasal absorption of paeoniflorin. Furthermore, water-soluble azone had the highest absorption rate constant and the best promoting penetration effect on intranasal administration preparations of paeoniflorin. It was also found that when the mass concentration of water-soluble azone in the perfusion liquid increased from 5 g•L⁻¹ to 20 g•L⁻¹, the absorption rate constant was gradually increased and peaked at 20 g•L⁻¹. When the mass concentration was increased to 30 g•L⁻¹, the absorption rate constant was decreased, indicating that the best mass concentration of water-soluble azone was 20 g•L⁻¹.

Nasal resorption of prim-O-glucosylcimifugin and 5-O-methylvisammioside in rats / 中国中药杂志

In this experiment, rat nasal mucosa absorption characteristics of prim-O-glucosylcimifugin and 5-O-methylvisammioside were studied to provide a basis for drug delivery of Toutongning nasal spray. The nasal mucosa absorption test in rats was conducted with in situ nasal perfusion method after pH 6 buffer solution was used to prepare high, medium and low concentrations of prim-O-glucosylcimifugin, 5-O-methylvisammioside mixed solution as liquid circulation in nasal cavity. Then the concentrations of the circulating liquid compositions to be measured were determined by HPLC, and the absorption rates of prim-O-glucosylcimifugin and 5-O-methylvisammioside under different pH conditions were also investigated. According to the results, the absorption rate constant was (0.588±0.041)×10⁻³, (0.547±0.023)×10⁻³, (0.592±0.063)×10⁻³ min⁻¹ for prim-O-glucosylcimifugin high, middle and low concentrations, and (0.438±0.041)×10⁻³, (0.407±0.023)×10⁻³, and (0.412±0.063)×10⁻³ min⁻¹ for 5-O-methylvisammioside high, middle and low concentrations. There was no significant difference among high, middle and low concentration groups, and the absorption under pH 6 was better than that under other pH conditions. Therefore, we can get the conclusion that the main active ingredient of Toutongning nasal sprays can be absorbed through the nasal mucosa, and it is feasible to make nasal spray; in addition, pH 6 of nasal spray is scientific and reasonable.

In vitro transdermal delivery of Qingfei Xiaocuo gel based on principal component analysis / 中国中药杂志

The objective of the present study was to establish a method based on principal component analysis (PCA) for the study of transdermal delivery of Chinese medicinal formulae, and to choose the best penetration enhancers for Qingfei Xiaocuo gel depend on this method. Using improved Franz type diffusion cell and excised rat skin in vitro as transdermal barrier, the receptive solution fingerprint was established by HPLC, harvesting the areas of the common peaks in the fingerprint, then the total factor scores of the concentrations at different times were calculated using PCA and were employed instead of the concentrations to compute the cumulative amounts (Q12) and enhancement ratio (ER), the latter of which were considered as the indexes for optimizing penetration enhancers. Compare to the control group, the ER of the other groups increased significantly and furthermore, 2.5% azone with 2.5% menthol manifested the best effect. PCA represent most information in the receptive solution, the method above could choose the best penetration enhancers, it could be a reference for the study of transdermal delivery of Chinese medicinal formulae.