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During the dry season of December 2020, two sliding subzones of the Qingliu landslide in southwest China slid out of stability, severely damaging the buildings on the slope. To investigate the mechanism and movement of landslides in the dry season, we employed high-resolution unmanned aerial vehicle mapping, electrical resistivity tomography, on-site union boreholes, groundwater detection, deep displacement monitoring, and numerical simulation to analyze the deep geotechnical structural characteristics, groundwater types and runoff paths, and destabilization range and movement processes at different times. Preliminary analysis showed that the slow infiltration of rainwater during the rainy season and infiltration of snow melt in winter, topography, and loess clay layers of the slide zone type are related to the triggers of landslide instability. Four layers of rock-soil stratification interfaces with different resistivity values, revealed by electrical resistivity tomographycomprising loess-like pulverized clay, gravelly pulverized clay, and bedrock, existed at different burial depths in the longitudinal section. Borehole and displacement monitoring revealed the existence of a primary slip surface and several secondary slip surfaces, with an average thickness of 16-22 m and a maximum daily displacement at the slip surface of approximately 2.29 mm. The deepest groundwater level of the water-bearing section in the borehole was 25.8 m, and it percolates and drains through fractures in the loess-like layer. Startup acceleration, deceleration pileup, front-edge pileup stopping, and middle- to rear-edge pileup stopping are the four primary discrete element simulation forecasting movement phases. The findings help deepen the understanding of similar dry-season landslides and their disaster-causing effects.Fig. 1 Geographical situation and geo-tectonic setting of H01 and H02 zoning of Qingliu landslide, Li County, Southwest China. (a. 1:500,000 regional geological map; b. High-resolution UAV orthophotography and geometric interpretation)

The impact of geohazards on mountainous settlement have been focused in recent years. Despite the booming development in the modeling of hazards and vulnerability, the risk assessment in mountainous area still have difficulty in absence of refined data. Moreover, development imbalances widely exist in mountainous areas, which ignored in previous researches. In this study, the development imbalances were quantified and integrated into risk assessment framework, which be applied in Lushan and Baoxing mountainous areas. The refined distribution of soc-economic data is obtained by using spatialization from the census, which eases the situation of the lack of data. Then, a frequency ratio-random forest (FR-RF) model is conducted to evaluate the geohazards hazard. Meanwhile, vulnerability was evaluated using triangular fuzzy number‑based analytic hierarchy process (TFN-AHP). In vulnerability assessment, the inhomogeneity index is integrated to evaluate the imbalance between indicators, the use of which can reward a more realistic vulnerability result. Finally, risk map was produced by multiplying hazard and vulnerability. The risk assessment framework is successfully applied in Lushan and Baoxing counties of Southwestern China, which is a typical mountainous area with frequent earthquakes, uneven development, and a lack of high-precision data. The total area of high and extremely high hazard (868.82 km2), vulnerability (258.66 km2), and risk (113.49 km2) are estimated and mapped.

High-mountain landslides in the hydrogeological environment expose the residents and properties of mountain settlements to immediate risks, especially in the southwestern part of the Tibetan Plateau, where severe damage is frequent. The risk assessment of geohazards is provided as an effective disaster prevention and mitigation management measure. To reasonably predict the spatial distribution characteristics of high-mountain landslide risks, the Gaussian process classification (GPC) and the improved weight-based generalized objective function were applied to quantify the hazard, vulnerability, and risk values of Li County, Southwest China. The findings revealed that the hazard, vulnerability, and risk levels in the studied areas were comparatively high, with percentages in the moderate–high ranges of 41.715%, 40.634%, and 57.135%, respectively. The towns of Zagunao, Ganbu, and Taoping are among the regions with a high grade of risk, with risk values of 0.407, 0.347, and 0.335, respectively. These high-risk distribution sites are concentrated predominantly in the municipalities and their fringes, whereas other prefectures are in the medium–below risk level range. Following the examination of the GPC model and integral appraisal performance, this risk assessment framework exhibits good predictability, with an accurate proportion of predictions in the hazardous location interval reaching 99.857% and an ROC-AUC value of 0.97. The proceedings of this study can provide essential materials and references for decision-making for hydrogeological-environmental hazard policy formulation, territorial spatial planning, and other regional-related risk assessment projects.

Debris flows are a common natural trigger of disasters in mountainous areas, and check dams are standard structural measures for controlling debris flows. Despite their prevalence in debris flow-prone areas worldwide, the capacity of check dams is still calculated using empirical formulas, which lead to large calculation errors. This paper proposes a new method that uses GIS to calculating the design storage capacity of a check dam in the debris flow-prone Cutou Gully in Wenchuan County, China. Large-scale digital surface models derived from unmanned aerial vehicle imagery and ground surveys identify local topographic changes in the debris flow path and develop appropriate maintenance plans for check dams. The measured storage capacity of the check dam is determined by analyzing the DEM differences. This study uses the newly proposed method to calculate the design storage capacity of the check dam. The accuracy of the calculation results was evaluated using the checkpoint method, and the results showed that the design and measured siltation surface errors ranged from -1.16-2.96 m, with a root mean square error of 0.93 m. The design capacity of the check dam is 33.6× 104 m3, and the actual capacity is 36.7× 104 m3, with an absolute error of 3.1× 104 m3 and relative error of 8.6%. The results prove the validity of the proposed calculation method; moreover, this study shows that the new method is accurate, easy to operate, and highly efficient for visualizing the spatial distribution of the siltation depth behind the check dam. This work will help improve future engineering decisions, design strategies, and find optimal design solutions to minimize the risk of debris flow hazards.

The upper reaches of Min River (The upper Min River) is located in Southwest China with significant mountain settlements, which are vulnerable to frequent geological hazards. Based on a field investigation, collation of yearbook data, and analysis through the use of SPSS statistical software, a vulnerability evaluation index system of geological hazards was devised. According to the actual field situation and the acquired data of the study area in 2006, 2009, and 2015, 16 indicators were selected as settlement vulnerability evaluation indexes of geological hazards. The indexes included population density, building coverage, and economic density. Based on the comprehensive evaluation model of entropy value, the dynamic change in the settlement vulnerability of geological hazards was analyzed. The results showed that population density, building coverage, economic density, and road density were the factors that affected the settlement vulnerability of geological hazards the most—Wenchuan earthquake caused considerable damage to the upper Min River, making the area the most vulnerable in 2009. However, its vulnerability decreased in 2015, which indicated that postearthquake reconstruction achieved significant results. Thus, the vulnerability has emerged as an important indicator reflecting the safety and healthy development of mountain settlements.

Frequent geological disasters such as debris flow and landslides in seismic zones are the primary causes of regional population and infrastructure losses. In this paper, the Contribution Weighting Superposition (CWS) model was used to establish a quantitative vulnerability assessment method of geohazards in the Qiaojia seismic area (SW China). The CWS approach uses three appraisal dimensions: exposure, response, and resilience. A total of 326 historical hazardous locations were selected and combined with ten subfactors—population density (PD), road density (RD), economic density (ED), building density (BD), farmland coverage (FC), ratio of primary industry (RPI), ratio of government revenue (RGR), urbanization rate (UR), GDP per capita (GPC), and disposable income per capita of rural permanent residents (RPR)—for predicting geological hazards vulnerability. Finally, Cohen's kappa coefficient (k) was applied to examine the consistency between the appraisal outcomes and the actual data concerning hazards. Results show that the overall vulnerability in this area is medium and above, with a high risk of widespread damage from potential calamities. PD, GR, and RPR are the three subfactors that most significantly affect the spatial distribution characteristics of vulnerability. The k value associated with the assessed and actual hazard observation data was 0.771 (95% CI 0.771 ± 0.039) with an approximate significance of P

The development and outbursts of glacial lake debris flow pose threats to downstream infrastructures. Thus, rational assessment of its potential hazards is necessary to mitigate geological hazards along the Sichuan–Tibet railway lines. In this paper, we used logistic regression models and Rapid Mass Movement Simulation methods to assess the multiyear dynamic evolutionary characteristics and outburst risks of the glacial lake and to conduct numerical simulation of the debris flow process. The adopted methodology used remote sensing images from the Landsat 1-Landsat 8 series for the period 1973–2018, combined with the pieces of information of the geological expedition in the glacial lake Dongcuoqu, Luolong County, Tibet, China. The results revealed that the probability of collapse risk of the Dongcuoqu glacial lake dam was 0.39, and its risk extent reached level I, which indicates medium hazardousness and severe loss. The debris flow process simulation comprises of four stages: initiation, acceleration, deceleration, and termination. The outburst floods flow through the proposed location of the Sichuan–Tibet railway. Specifically, the flow velocity in the vicinity of the Luolong station of nearly 5 m/s, which poses a significant threat to the safe construction of the railway. In the flood and non-flood periods, the change in the amount of snow and ice melt was distinctive, and the maximum storage capacities of the glacial lake during these periods were 82 × 106 m3 and 60.1 × 106 m3, respectively. These findings suggest that the assessment results can be used as an excellent reference for the reduction of the construction risk of the proposed Sichuan–Tibet railway under disaster stress in glacial lake outburst hazard areas.

Once urinary bladder cancer (UBC) develops into muscle-invasive bladder cancer, its mortality rate increases dramatically. However, the molecular mechanisms of UBC invasion and metastasis remain largely unknown. Herein, using 5637 UBC cells, we generated two sublines with low (5637 NMI) and high (5637 HMI) invasive capabilities. Mass spectrum analyses revealed that the Wnt family protein Wnt7a is more highly expressed in 5637 HMI cells than in 5637 NMI cells. We also found that increased Wnt7a expression is associated with UBC metastasis and predicted worse clinical outcome in UBC patients. Wnt7a depletion in 5637 HMI and T24 cells reduced UBC cell invasion and decreased levels of active β-catenin and its downstream target genes involved in the epithelial-to-mesenchymal transition (EMT) and extracellular matrix (ECM) degradation. Consistently, treating 5637 NMI and J82 cells with recombinant Wnt7a induced cell invasion, EMT, and expression of ECM degradation–associated genes. Moreover, TOP/FOPflash luciferase assays indicated that Wnt7a activated canonical β-catenin signaling in UBC cells, and increased Wnt7a expression was associated with nuclear β-catenin in UBC samples. Wnt7a ablation suppressed matrix metalloproteinase 10 (MMP10) expression, and Wnt7a overexpression increased MMP10 promoter activity through two TCF/LEF promoter sites, confirming that Wnt7a-mediated MMP10 activation is mediated by the canonical Wnt/β-catenin pathway. Of note, the microRNA miR-370-3p directly repressed Wnt7a expression and thereby suppressed UBC cell invasion, which was partially restored by Wnt7a overexpression. Our results have identified an miR-370-3p/Wnt7a axis that controls UBC invasion through canonical Wnt/β-catenin signaling, which may offer prognostic and therapeutic opportunities.

PCL-heparin conjugates were synthesized by coupling mono-hydroxyl terminated PCL (Mn = 2000-10000 g/mol) with heparin via EDC/NHS chemistry. The conjugates enabled to self-assemble into the core-shell nanoparticles in around 100 nm diameter to load binary anti-cancer drugs. Lipophilic and neutral paclitaxel (PTX) was first encapsulated in the core, and then hydrophilic and positive charged doxorubicin (DOX) was incorporated into the negative charged shell of PTX loaded nanoparticles via the electrostatic interaction. The in vitro release profiles of the binary-drug loaded nanoparticles revealed that both PTX and DOX were sustainably released from the particles but behaved differently. The release of DOX was pH dependent, ensuring more drug to be released in the tumor cells than in the normal ones. Hence these particles were featured by a sequential controlled drug delivery behavior with a significant cytotoxicity to cervical cancer (Hela cell) and breast cancer (MDA-MB-321) cells. The CLSM observations clearly indicated that both loaded PTX and DOX aggregated in the nucleus of tumor cells to exert their anti-tumor pharmacodynamic effect on the cells.