Time-moduated nonreciprocal metasurface absorber for surface waves.

We have investigated a magnet-free, nonreciprocal surface wave absorber based on high impedance surfaces (HISs) using a spatial-temporal modulation approach. By controlling embedded switches with a travelling wave, the HIS metasurface is modulated to break the time and spatial symmetry, which enables surface waves to propagate in one direction but be absorbed when propagating in the reverse direction. The nonreciprocity has been demonstrated by an EM-circuit co-simulation. We envision that this could be possibly applied in future communication systems that preferably transmit unidirectionally but absorb interference from the reverse direction caused by reflections or other devices.

Chemical Diversity and Prediction of Potential Cultivation Areas of Cistanche Herbs.

Owing to hostile growth environments and increasing related production, Cistanche plants have decreased in number. The aim of the present study was to evaluate the quality of and to predict potential suitable regions for two official species and two nonofficial species (C. salsa and C. sinensis) by high-performance liquid chromatography and the MaxEnt model. The results indicated that 2'-acetylacteoside was present only in C. deserticola. The compound can be used as a potential chemical marker to discriminate C. deserticola from the three other Cistanche plants. Anthocyanin A and carotenoid F were the common constituents of the two official species only and can thus be used as chemical markers to differentiate between official and nonofficial species. The prediction results of a potentially suitable distribution indicated that C. sinensis has much wider regions for potential distribution than the other species. Finally, the echinacoside content in C. deserticola was significantly different between the two suitable potential distributions, and the contents of samples from Inner Mongolia were significantly higher than those from Gansu Province. This is the first application of the combination of the contents of chemical components and the results of MaxEnt models for the quality assessment of herbal medicine. Our results may provide a reference for the sustainable utilization of endangered Cistanche species.

An Integrated LC-MS-Based Strategy for the Quality Assessment and Discrimination of Three Panax Species.

: The quality assessment and discrimination of Panax herbs are very challenging to perform due to the complexity and variability of their chemical compositions. An integrated strategy was established using UHPLC-Q-Exactive/HRMS and HPLC-ESI-MS/MS to achieve an accurate, rapid, and comprehensive qualitative and quantitative analysis of Panax japonicas (PJ), Panax japonicus var. major (PM), and Panax zingiberensis (PZ). Additionally, discrimination among the three species was explored with partial least squares⁻discriminant analysis (PLS-DA) and orthogonal partial least squares⁻discriminant analysis (OPLS-DA) score plots. A total of 101 compounds were plausibly or unambiguously identified, including 82 from PJ, 78 from PM, and 67 from PZ. Among them, 16 representative ginsenosides were further quantified in three herbs. A clear discrimination between the three species was observed through a multivariate statistical analysis on the quantitative data. Nine compounds that allowed for discrimination between PJ, PM, and PZ were discovered. Notably, ginsenoside Rf (G-Rf), ginsenoside F3 (G-F3), and chikusetsu saponin IV (CS-IV) were the three most important differential compounds. The research indicated that the integrated LC-MS-based strategy can be applied for the quality assessment and discrimination of the three Panax herbs.

Predicting the Global Potential Distribution of Four Endangered Panax Species in Middle-and Low-Latitude Regions of China by the Geographic Information System for Global Medicinal Plants (GMPGIS).

Global biodiversity is strongly influenced by the decrease in endangered biological species. Predicting the distribution of endangered medicinal plants is necessary for resource conservation. A spatial distribution model-geographic information system for global medicinal plants (GMPGIS)-is used to predict the global potential suitable distribution of four endangered Panax species, including Panax japonicas (T. Nees) C. A. Meyer and Panax japonicas var. major (Burkill) C. Y. Wu & K. M. Feng distributed in low- and middle-latitude, Panax zingiberensis C. Y. Wu & K. M. Feng and Panax stipuleanatus C. T. Tsai & K. M. Feng in low-latitude regions of China based on seven bioclimatic variables and 600 occurrence points. Results indicate that areas of P. japonicus and P. japonicusvar. major are 266.29 × 105 and 77.5 × 105 km², respectively, which are mainly distributed in China and America. By contrast, the areas of P. zingiberensis and P. stipuleanatus are 5.09 × 105 and 2.05 × 105 km², respectively, which are mainly distributed in Brazil and China. P. japonicus has the widest distribution among the four species. The data also indicate that the mean temperature of coldest quarter is the most critical factor. This scientific prediction can be used as reference for resource conservation of endangered plants and as a guide to search for endangered species in previously unknown areas.