Numerical analysis of downward progressive landslides in long natural slopes with sensitive clay

Landslides occurring in sensitive clay often result in widespread destruction,posing a significant risk to human lives and property due to the substantial decrease in undrained shear strength during deformation.Assessing the consequences of these landslides is challenging and necessitates robust numerical methods to comprehensively investigate their failure mechanisms.While studies have extensively explored upward progressive landslides in sensitive clays,understanding downward progressive cases remains limited.In this study,we utilised the nodal integration-based particle finite element method(NPFEM)with a nonlinear strain-softening model to analyse downward progressive landslides in sensitive clay on elongated slopes,induced by surcharge loads near the crest.We focused on elucidating the underlying failure mechanisms and evaluating the effects of different soil parameters and strainsoftening characteristics.The simulation results revealed the typical pattern for downward landslides,which typically start with a localised failure in proximity to the surcharge loads,followed by a combination of different types of failure mechanisms,including single flow slides,translational progressive landslides,progressive flow slides,and spread failures.Additionally,inclined shear bands occur within spread failures,often adopting distinctive ploughing patterns characterised by triangular shapes.The sensitive clay thickness at the base,the clay strength gradient,the sensitivity,and the softening rate significantly influence the failure mechanisms and the extent of diffused displacement.Remarkably,some of these effects mirror those observed in upward progressive landslides,underscoring the interconnectedness of these phenomena.This study contributes valuable insights into the complex dynamics of sensitive clay landslides,shedding light on the intricate interplay of factors governing their behaviour and progression.

白血病细胞中翻译控制肿瘤蛋白的检测及其方法学比较

目的 ：比较蛋白印迹法和流式细胞术（flow cytometry,FCM）在检测细胞内翻译控制肿瘤蛋白（translationally controlled tumor protein,TCTP）中的优势,并分析两者在临床检测中的应用价值。方法 ：用1μmol/L全反式维A酸（all-trans-retinoic acid,ATRA）处理NB4和NB4-R1细胞0~96 h,分别采用蛋白印迹法和FCM检测细胞内TCTP蛋白的变化情况,用Bland-Altman分析法分析检测结果的一致性。用FCM检测部分急性白血病患者骨髓原代标本中TCTP蛋白水平。结果 ：蛋白印迹法检测结果显示,经ATRA处理后NB4细胞内TCTP下降,各时间点（0、24、48、72、96 h）TCTP与β-actin灰度比的相对值分别为1.00、0.97±0.05、0.91±0.03、0.85±0.05和0.72±0.02,而NB4-R1细胞中则保持不变。FCM检测结果显示,经ATRA处理后NB4细胞内各时间点TCTP的阳性率分别为（98.93±0.49）%、（98.83±0.65）%、（96.77±1.45）%、（90.93±1.35）%和（72.17±5.57）%,NB4-R1细胞中保持不变。根据Bland-Altman法,计算可得2种方法测量值95%的一致性区间界限为（-0.081,0.111）,本研究所测得的30组数据中有29组落在区间内。对11例急性白血病患者和9例非白血病患者骨髓细胞内TCTP水平的检测结果显示,非白血病患者骨髓细胞内TCTP的表达较低,而白血病患者则相对较高,两者间差异有统计学意义（P〈0.01）。结论：蛋白印迹法与FCM检测细胞内TCTP蛋白水平的结果间有良好的一致性,而FCM更加适用于患者的原代标本检测。细胞内TCTP水平的高低可能与白血病的发生、发展有关,今后有可能作为临床白血病检测的分子标志物。