Determination of Naringin Content in Rhizoma Drynariae by High Performance Liquid Chromatography

[Objectives]To accurately determine the naringin content in Rhizoma Drynariae.[Methods]The high performance liquid chromatography(HPLC)method was applied in the determination of the naringin content in Rhizoma Drynariae.The sample was sonicated at room temperature.The mobile phase was 0.1%phosphoric acid-acetonitrile(75∶25),detected by diode array detector at the wavelength of 284 nm,and quantified by external standard method.[Results]The linearity of naringin was good in the concentration range of 5-500μg/mL with a correlation coefficient of 0.9999.[Conclusions]This method has good linearity,easy operation,correctness and reproducibility as required,and is expected to provide a method for the determination of naringin content in Rhizoma Drynariae.

Simultaneous Determination of Content of VK_(1) and VK_(2) in Milk and Dairy Products by High Performance Liquid Chromatography

[Objectives]To make simultaneous determination of vitamin K_(1)(VK_(1))and vitamin K_(2)(VK_(2),mainly MK-4,MK-7 and MK-9)in milk and dairy products.[Methods]A high performance liquid chromatographic method was developed for the simultaneous determination of vitamin K_(1)(VK_(1))and vitamin K_(2)(VK_(2),mainly MK-4,MK-7 and MK-9)in milk and dairy products.After enzymatic digestion,the samples were extracted with hexane for VK_(1),MK-4,MK-7 and MK-9,subjected to gradient elution at excitation wavelength 243 nm and emission wavelength 430 nm,detected by high performance liquid chromatography with fluorescence detector and quantified by external standard method.[Results]The linearity of VK_(1),MK-4,MK-7 and MK-9 was good in the concentration range of 2.5-1000 ng/mL with the correlation coefficients greater than 0.999;The relative standard deviations(RSD)of VK_(1),MK-4,MK-7 and MK-9 in milk powder,liquid milk and yogurt were 1.32%-5.05%,1.10%-2.48% and 2.20%-3.47%,respectively;the recovery rates of VK_(1),MK-4,MK-7 and MK-9 at different levels in milk powder,liquid milk and yogurt were 81.1%-108%,81.8%-103%and 82.1%-99.2%,respectively.[Conclusions]The method is rapid,accurate,reproducible and capable of simultaneous determination of VK_(1),MK-4,MK-7 and MK-9.

Spatiotemporal Evolution Analysis of the 3-D Deformation Field of Land Subsidence in Beijing after the South-to-North Water Diversion Project

The implementation of the South-to-North Water Diversion Project (SNWDP) has alleviated groundwater resource pressure in North China to some extent, resulting in a gradual deceleration of land subsidence and even rebound in some areas. To investigate the spatiotemporal evolution characteristics of land subsidence in the eastern plain of Beijing following the SNWDP, this study employs Ascending (ASC) and Descending (DES) InSAR data combined with a Strain Model (SM) to obtain a Three-Dimensional (3-D) deformation field from 2016 to 2018. Through analysis of the 3-D deformation characteristics and spatiotemporal evolution of land subsidence in this region from 2016 to 2018, the results reveal a shift in the distribution of subsiding areas after the South-to-North Water Diversion, with a marked decrease in subsidence rates in certain areas. The maximum subsidence rate in the Beijing area has decreased to 110 mm/yr, accompanied by horizontal deformation at a rate of 12 mm/yr. Additionally, by examining the spatial relationship between major active faults and subsidence deformation in this region, the study further elucidates the influence of fault activity on the spatial distribution of subsidence deformation.

Development of plant communities after restoration of the Antaibao mining site, China

To investigate the dynamic changes in the artificial vegetation in an abandoned mining site,we analyzed the re lationships among community types,environmental variables and community structure in the process of vegetation restoration in the Antaibao mining site,China by survey of the communities and use of biological dating methods.By means of the quantitative classification method(two-way indicator-species analysis,TWINSPAN)and the ordination technique(de-trended correspondence analysis,DCA;and de-trended canonical correspondence analysis,DCCA),the plant communities were classified into seven groups:community I,Robinia pseudoacacia+Pimus tabulaeformis-Caragana kor-shinskii-Agropyron cristatum;community II,Robinia pseudoacacia-Hippophae rhamnoides-Artemisia capil-laries;community II,Ulmus pumila-Elaeagmus angu-stifolia-Artemisia capillaries;community IV,Caragana korshinskii-Agropyron cristatum+Artemisia capillaries;community V,Hippophae rhamnoides-Elymus dahur-icus;community VI,Elaeagnus angustifolia+Hippophae rhamnoides-Brassica jucea;community VII,Hippophae rhammoides+Elaeagnus angustifolia-Salsola collina.We conclude that the community types and diversity are mainly influenced by the succession time and the soil organic matter content.The forest community is more adaptable to the special inhabitation than the shrub community.