Objective To investigate the spatial distribution patterns and environmental determinants of Lagotis brachystachya Maxim.,a keystone species in Tibetan medicine("Zhi Da Sa Zeng"),under contemporary climatic conditions in China;To provide references for the sustainable utilization of its resources and the ecological protection of alpine grassland areas.Methods Based on the maximum entropy model,the selected species distribution data and environmental factors were added to MaxEnt 4.3.1 software for modeling.The geographical detector was applied to quantify the factors influencing the spatial differentiation of the suitable areas,employing both factor detection and interaction detection functionalities.Additionally,an overlay analysis with land cover types was conducted to quantify the distribution characteristics of grassland within the potential suitable areas for Lagotis brachystachya Maxim..Results Under the current climatic conditions,dominant environmental drivers included elevation,monthly average temperature difference between day and night,average precipitation in June,wind speed in September,solar radiation in August,average precipitation in May,average precipitation in October,among which elevation demonstrated the strongest explanatory power(q=0.37)in habitat suitability analysis.The model prediction results showed that the potential suitable area for Lagotis brachystachya Maxim.was 5.31×105 km2.Considering the type of surface coverage,the main suitable habitat for Lagotis brachystachya Maxim.was grassland,with an area of 4.34×105 km2.The high suitable grassland of areas were mainly distributed in Qinghai Province(Yushu Tibetan Autonomous Prefecture,Huangnan Tibetan Autonomous Prefecture,Golog Tibetan Autonomous Prefecture,Hainan Tibetan Autonomous Prefecture,Haibei Tibetan Autonomous Prefecture),Sichuan Province(Ganzi Tibetan Autonomous Prefecture,Aba Qiang Autonomous Prefecture),Xizang Autonomous Region(Naqu City,Shigatse City,Changdu City),and Gansu Province(Gannan Tibetan Autonomous Prefecture).Conclusion This study can provide references for the protection of wild resources and the selection of domestication and cultivation areas for Lagotis brachystachya Maxim..

Objective To investigate the spatial distribution patterns and environmental determinants of Lagotis brachystachya Maxim.,a keystone species in Tibetan medicine("Zhi Da Sa Zeng"),under contemporary climatic conditions in China;To provide references for the sustainable utilization of its resources and the ecological protection of alpine grassland areas.Methods Based on the maximum entropy model,the selected species distribution data and environmental factors were added to MaxEnt 4.3.1 software for modeling.The geographical detector was applied to quantify the factors influencing the spatial differentiation of the suitable areas,employing both factor detection and interaction detection functionalities.Additionally,an overlay analysis with land cover types was conducted to quantify the distribution characteristics of grassland within the potential suitable areas for Lagotis brachystachya Maxim..Results Under the current climatic conditions,dominant environmental drivers included elevation,monthly average temperature difference between day and night,average precipitation in June,wind speed in September,solar radiation in August,average precipitation in May,average precipitation in October,among which elevation demonstrated the strongest explanatory power(q=0.37)in habitat suitability analysis.The model prediction results showed that the potential suitable area for Lagotis brachystachya Maxim.was 5.31×105 km2.Considering the type of surface coverage,the main suitable habitat for Lagotis brachystachya Maxim.was grassland,with an area of 4.34×105 km2.The high suitable grassland of areas were mainly distributed in Qinghai Province(Yushu Tibetan Autonomous Prefecture,Huangnan Tibetan Autonomous Prefecture,Golog Tibetan Autonomous Prefecture,Hainan Tibetan Autonomous Prefecture,Haibei Tibetan Autonomous Prefecture),Sichuan Province(Ganzi Tibetan Autonomous Prefecture,Aba Qiang Autonomous Prefecture),Xizang Autonomous Region(Naqu City,Shigatse City,Changdu City),and Gansu Province(Gannan Tibetan Autonomous Prefecture).Conclusion This study can provide references for the protection of wild resources and the selection of domestication and cultivation areas for Lagotis brachystachya Maxim..

Objective To evaluate the value of 3T magnetic resonance imaging (MRI) in the preoperative T staging of potentially resectable esophageal cancer(EC), compared with endoscopic ultrasonography (EUS). Methods Patients with resectable EC pathologically confirmed by biopsy from March 2015 to September 2016 were prospectively enrolled. All patients underwent MRI (including T2-TSE-BLADE,DWI and radial-VIBE)and EUS one week after the biopsy,and MRI were performed prior to EUS, both MRI and EUS were acquired within one week before surgery. Two readers with more than 5 years experiences in the MRI diagnosis evaluated the MR image quality using a 5-point score independently. T staging was assigned on MRI and EUS by the two MRI readers using double-blind method and one endoscopist in accordance with the 7th edition of AJCC TNM Classification for EC, and any disagreement between two MRI readers was resolved by consensus with discussion to the third senior MRI doctor. The inter-observer agreement between two MRI readers were calculated using Kappa test for image quality scores and T staging results. Considering postoperative pathological T staging results as the gold standard, the performances of MRI and EUS were evaluated based on the accuracy rate and analyzed by χ2 test. Results A total of 70 patients were enrolled in the study, the good image quality cases (≥ 3 scores) were 66 in reader 1 and 68 in reader 2. The inter-observer agreement of the image quality scores by two readers was excellent (Kappa=0.824, P<0.05). The pathological results revealed 16 cases of T1 stage, 18 cases of T2 stage, 30 cases of T3 stage, and 6 cases of T4a stage. The inter-observer agreement of the preoperative T staging of EC by two readers was excellent (Kappa=0.809, P<0.05). The accuracy rates of MRI and EUS for preoperative T staging of EC were 92.9% (65/70) and 67.1% (47/70), respectively, and the difference in accuracy rates of two techniques was statistically significant (χ2=14.5, P<0.05). Conclusions The accuracy rate of MRI for preoperative T staging of EC is significantly higher than that of EUS. MRI can be used as a noninvasive method for preoperative T staging of EC.