Search

Urban cover-collapse sinkholes pose a significant global challenge due to their destructive impacts. Previous studies have identified groundwater fluctuations, subsurface soil conditions, pipeline leakage, precipitation, and subterranean construction activities as key contributors to these phenomena. However, unique geological settings across different urban environments lead to variations in the primary factors influencing sinkhole formation. This study focuses on Shanghai, a city notable for its extensive urbanization and rich historical context, to explore the dynamics of sinkholes within urbanized areas worldwide. We employ spatial analysis and statistical methods to examine data on sinkholes recorded in the past two decades in Shanghai, correlating these events with the city's shallow sand layer, ground elevation, and proximity to surface water. Our goal is to identify the dominant factors governing sinkhole occurrence in Shanghai and to lay the groundwork for their effective scientific management and prevention. Key findings indicate that most sinkholes in the area are associated with a thin shallow sand layer, low to moderate ground elevations, and the absence of nearby rivers. Additionally, many sinkholes correlate with subterranean voids within the confined aquifer beneath the cohesive soil layer. The lack of historical river channels, obscured by urban development, also indirectly contributes to sinkhole formation. We recommend enhancing urban river management and drainage systems to mitigate potential damage from water accumulation. [ABSTRACT FROM AUTHOR]

Summary: The asymptotic stabilization problem is studied for a cascade connection of passive switched nonlinear systems and a passive switched nonlinear system in this paper. When each subsystem is asymptotically zero state detectable and passive on active time intervals, asymptotic stabilization is achieved via co‐design of switching laws and controllers without damping injection. First, an output‐feedback controller is designed to asymptotically stabilize a cascade connection of two passive switched systems if outputs are measurable. Second, when the output of the first switched system is noisy or unmeasurable, a sampled integral stabilization (SIS) technique is employed to investigate asymptotical stabilization of a cascade connection by measuring only the storage function of the second switched system. Finally, as a special case of a cascade connection, the SIS technique is used to stabilize a passive switched system without damping injection. Under this circumstance, the controller is designed by sampling the integral of the passive output. The two‐link robot manipulator is provided to illustrate the effectiveness of the SIS technique. [ABSTRACT FROM AUTHOR]

In this study, finite‐time passivity of switched non‐linear systems is developed. First, a finite‐time passivity concept is proposed using multiple storage functions. Second, a switching law is designed to make a switched non‐linear system finite‐time passive. Third, on the basis of the proposed concept, finite‐time passivity properties are investigated. On the one hand, finite‐time passivity can induce finite‐time stability. On the other hand, finite‐time passivity is preserved under the feedback interconnection and parallel interconnection. Furthermore, the merging switching signal technique is employed to make an interconnected system finite‐time passive. Finally, an example is provided to demonstrate the effectiveness of the obtained results. [ABSTRACT FROM AUTHOR]

Local passivity andH∞control of switched discrete-time nonlinear systems are studied using the linearisation technique in this paper. We first establish LMI-based sufficient conditions under which theconsidered system is locally strictly QSR-dissipative. Then, two special cases of QSR-dissipativity, local passivity andl2gain, are investigated. In view of the derived conditions being all convex in linearised system matrices, local feedback passification andH∞control problems of switched discrete-time nonlinear systems are solved. The efficiency of the proposed method is verified through numerical examples. [ABSTRACT FROM PUBLISHER]

Cities have become significant sources of greenhouse gas emissions. Effective land management may be the solution to carbon neutrality targets for megacities with limited land resources. This paper takes Shanghai as a case study to investigate the regional land use dynamics and its impact on carbon emissions following the implementation of land conservation and intensive use policy. During 2010–2020, the land use pattern in Shanghai changed from the previous urban land expansion to a combination of industrial land reduction and woodland expansion. Meanwhile, the area proportion of land-use mixture grids increased from 90.50% to 92.28% with the spatial pattern of mixed types also changing. Furthermore, the notable land-use mixture does not necessarily lead to carbon emission reduction, but it can reduce carbon emission hotspots in industrial agglomerations by promoting the mixed use of industrial land and other land use types. However, megacities cannot achieve carbon balance through land use management alone. Due to the increasing carbon emission density of hybrid industrial land, the joint implementation of a land conservation and intensive use strategy with industrial and energy structure adjustments may be an effective way forward. [Display omitted] • Land use change in Shanghai over the past decade resulted in positive carbon sinks. • Impact of land-use mixture on carbon emission was evaluated for the first time. • The reduction and intensive use of industrial land is the new land-use pattern. • Hybrid industrial land helps reduce carbon hotspots in industrial agglomerations. [ABSTRACT FROM AUTHOR]

The vertical–horizontal curtain system (VH curtain) is sometimes utilized in foundation pit dewatering under complex hydrogeological conditions. However, the working mechanism of this system when the horizontal curtain is semi-permeable and cannot completely cut off the bottom aquifer remains unknown. A transparent soil physical model test was performed to reveal the water control mechanism of the VH curtain system with a semi-permeable horizontal curtain. A multi-point inert tracer with a high-speed camera was used to photograph the seepage process. The seepage mode was revealed via a model test. With the Shanghai deep tunnel project as background, a numerical simulation was performed to understand the utilization of the VH curtain. The influence of horizontal curtain position, horizontal curtain thickness, horizontal curtain hydraulic conductivity, and VH curtain combination form on the seepage path around the foundation pit and on the drawdown of water level inside and outside the pit were studied. Results provide a basis for the engineering application of the VH curtain pumping well system. [ABSTRACT FROM AUTHOR]

Background Heterotopic gastric mucosa in the upper esophagus (HGMUE) is reported to be related to gastroesophageal reflux disease (GERD). This study investigated the prevalence of GERD and the use of salivary pepsin to diagnose gastroesophageal reflux, especially proximal reflux, in HGMUE patients. Methods One hundred and fifty-three HGMUE patients and 50 healthy volunteers were studied. All subjects took a reflux symptom index questionnaire (RSI); underwent endoscopy, barium esophagogram, high-resolution manometry (HRM), and 24-hour multichannel intraluminal impedance-pH-metry (MII-pH); and salivary pepsin test. Results Ninety-five (62.1%) HGMUE patients but no control subjects were diagnosed with GERD. The salivary pepsin concentration, RSI score, DeMeester score, acid exposure time (AET), total reflux episodes, proximal acidic reflux episodes, and proximal weakly acidic reflux episodes were significantly higher in the HGMUE group than in the control group (P  < 0.05). The salivary pepsin test showed a sensitivity of 85.9% and specificity of 56.9% for diagnosing GERD using the optimal cut-off value of 75 ng/mL. One hundred and seven (69.9%) and 46 (30.1%) HGMUE patients were categorized as pepsin (+) and pepsin (−), respectively when 75 ng/mL was used as a cut-off value. Male sex, RSI, AET, and proximal acid reflux episodes were positive predictive factors for the occurrence of pepsin (+) in HGMUE patients. Conclusions GERD, especially GERD with proximal acid reflux and related symptoms, was common in HGMUE patients. The salivary pepsin test could be an additional useful test for testing reflux in HGMUE patients, but it will not replace the MII-pH. [ABSTRACT FROM AUTHOR]

Groundwater level has to be lowered during deep excavation. A vertical curtain is usually adopted to control the drawdown inside and outside a foundation pit in a built-up area. However, the cost and working difficulty increases substantially with the rise in depth of vertical curtains. In the manuscript, a man-made horizontal seepage reducing body (HSRB) was introduced to shorten the vertical curtain depth and control drawdown. With the No. 4 shaft foundation pit of Guangyuan Project, Shanghai as background, HSRB was proposed in foundation pit dewatering. Microbially induced carbonate precipitation grouting technology was recommended to form an environment-friendly HSRB. Numerical method was used to simulate and understand the influence of position, thickness, and hydraulic conductivity of HSRB on groundwater level. The non-separated HSRB was better than the separate HSRB. Decreasing HSRB hydraulic conductivity was better than increasing HSRB depth. Four seepage modes were summarized considering vertical curtain penetration conditions into multi-aquifer, and the fifth seepage mode was formed for vertical curtain using man-made HSRB, which can be referred by similar engineering applications. [ABSTRACT FROM AUTHOR]

Purpose: Although laparoscopic Nissen fundoplication (LNF) is a kind of minimally invasive surgery, some transition time may still be required to allow the fundoplicated stomach to adapt to the new anatomical position. We observed transient delayed gastric emptying (DGE) post-LNF in our preliminary study. This study aimed to investigate the occurrence rate and development of transient DGE post-LNF. Methods: Patients who underwent LNF for gastroesophageal reflux disease (GERD) at our institution were recruited consecutively. They were treated with standardized LNF and prospectively followed up for 2 months. Proper diet guidance and/or pharmacologic therapy were given during these 2 months. GERD Health-Related Quality of Life (GERD-HRQL), DGE symptoms, and DGE status were evaluated preoperatively and postoperatively. Results: Fifty-one patients underwent LNF and completed a 2-month follow-up. LNF succeeded in all patients. Prior to LNF, no DGE was identified. At the 1-month follow-up, LNF led to a significant reduction in the GERD-HRQL total score but a significantly increased DGE score. Endoscopically, DGE was identified in forty-seven (n = 47, 92.2%) patients. At the 2-month follow-up, the GERD-HRQL scores continued to show decreases compared to the 1 month. The DGE score returned to the baseline value. Endoscopically, no DGE was identified in any patients (n = 0, 0.0%). Conclusions: Transient DGE is a very common one-month post-LNF but can recover quickly in the second month following LNF. [ABSTRACT FROM AUTHOR]

Ovarian cancer is a type of common gynecological tumors with high incidence and poor survival. The anticancer effects of the traditional Chinese medicine Solanum lyratum Thunb (SLT) have been intensively investigated in various cancers but in ovarian cancer is rare. The current study is aimed at investigating the effect of SLT on ovarian cancer cells. Lactate dehydrogenase (LDH) and MTT assays indicated that SLT concentrations of 0.25 and 0.5 μg/mL were not cytotoxic and had significant inhibitory effects on the cell viabilities of A2780 and SKOV3 cells, hence were used for subsequent experiments. Flow cytometric and western blot analysis revealed that SLT effectively suppressed ovarian cancer cell proliferation via inducing cell cycle arrest and increasing apoptosis. Cell cycle and apoptosis-related protein expressions were also regulated in SLT-treated cells. Moreover, DCFH-DA and western blot assays demonstrated that SLT enhanced ROS accumulation and subsequently activated the p53 signaling pathway. However, SLT-regulated ovarian cancer cell proliferation, apoptosis, migration, invasion, and EMT were significantly reversed by an ROS inhibitor (NAC, N-acetyl-L-cysteine). Furthermore, A2780 and SKOV3 cells cocultured with M0 macrophages showed that SLT activated the polarization of M0 macrophages to M1 macrophages and inhibited the polarization to M2 macrophages, with the increased percentage of CD86+ cells and decreased percentage of CD206+ cells were detected. In summary, this study illustrated the anticancer effects of SLT on ovarian cancer cells, suggesting that SLT may have the potential to provide basic evidence for the discovery of antiovarian cancer agents. [ABSTRACT FROM AUTHOR]

Highlights • A new denitration method which combined MOFs with NTP method was proposed. • An ultra-efficient efficiency of 97.87% was gained requiring no reducing agent. • A synergistic effect between MOFs and NTP was verified. • NO was mainly reduced to N 2 by activated CuBTC and NTP at ambient temperature. Abstract In this work, a new MOFs-NTP synergistic method was first proposed in order to study the denitration performance. As a highly efficient MOFs material, CuBTC was synthesized by microwave method and combined with non-thermal plasma (NTP) which achieved an ultra-efficiency of 97.87% for NO removal. It was 76.77% and 64.43% higher than that of the CuBTC-alone process and NTP-alone denitration process. The influential factors and characterization analysis (SEM, XRD, N 2 adsorption-desorption isotherms, ESR, XPS) were also investigated to study the synergistic effect of the MOFs-NTP denitration process. The results showed that CuBTC could be activated by NTP and generated the coordinatively unsaturated Cu(I)/Cu(II) sites which greatly enhanced the surface catalytic activity of CuBTC. NO was mainly reduced by Cu(I) sites to N 2. Cu(II) species can also be reacted with NO to generate Cu2+⋯(NO) adducts. The increase of carbonyl groups (C O) and carboxyl groups (COO) content also improved the chemisorption property of CuBTC. The results have shown that MOFs can serve as an ultra-efficient gas pollution adsorption material and will be more widely to be used in the field of environmental protection in the future. [ABSTRACT FROM AUTHOR]

The article presents the discussion on global population facing a high probability of land subsidence. Topics include natural or anthropogenic triggers resulting from solid or fluid mobilization underground; reducing aquifer-system storage capacity, causing earth fissures, damaging buildings, and civil infrastructure; and raising awareness and informing decision-making by evaluating potential global subsidence due to groundwater depletion.

Partial expansion was observed in stratified subsidence during foundation pit dewatering. However, the phenomenon was suspected to be an error because the compression of layers is known to occur when subsidence occurs. A slice of the subsidence cone induced by drawdown was selected as the prototype. Model tests were performed to investigate the phenomenon. The underlying confined aquifer was generated as a movable rigid plate with a hinge at one end. The overlying layers were simulated with remolded materials collected from a construction site. Model tests performed under the conceptual model indicated that partial expansion occurred in stratified settlements under coordination deformation and consolidation conditions. During foundation pit dewatering, rapid drawdown resulted in rapid subsidence in the dewatered confined aquifer. The rapidly subsiding confined aquifer top was the bottom deformation boundary of the overlying layers. Non-coordination deformation was observed at the top and bottom of the subsiding overlying layers. The subsidence of overlying layers was larger at the bottom than at the top. The layers expanded and became thicker. The phenomenon was verified using numerical simulation method based on finite difference method. Compared with numerical simulation results, the boundary effect of the physical tests was obvious in the observation point close to the movable endpoint. The tensile stress of the overlying soil layers induced by the underlying settlement of dewatered confined aquifer contributed to the expansion phenomenon. The partial expansion of overlying soil layers was defined as inversed rebound. The inversed rebound was induced by inversed coordination deformation. Compression was induced by the consolidation in the overlying soil layers because of drainage. Partial expansion occurred when the expansion exceeded the compression. Considering the inversed rebound, traditional layer-wise summation method for calculating subsidence should be revised and improved. [ABSTRACT FROM AUTHOR]

Glioblastoma (GBM) is one of the most common and malignant types of primary cancer in the central nervous system; however, the clinical outcomes of patients with GBM remain poor. Circular RNAs (circRNAs) have been revealed to serve important roles in diverse biological processes, such as regulating cell proliferation, epithelial-mesenchymal transition and tumor development. However, the underlying biological function of circRNA filamin A (circFLNA) and its potential role in GBM remain to be determined. The present study aimed to identify differentially expressed circRNAs in GBM. Reverse transcription-quantitative PCR was used to analyze the expression levels of circFLNA. The results demonstrated that the expression levels of circFLNA were significantly upregulated in clinical GBM samples and GBM cells compared with adjacent healthy brain tissues and normal human astrocytes, respectively. The results of the Cell Counting Kit-8 and Transwell assays revealed that circFLNA knockdown significantly inhibited the proliferative and invasive abilities of GBM cell lines. Moreover, high circFLNA expression levels were associated with a worse prognosis in GBM. MicroRNA (miR)-199-3p was subsequently predicted to be target of circFLNA. The inhibitory effect of miR-199-3p on cell proliferation and invasion was partially reversed following circFLNA knockdown. In conclusion, the findings of the present study identified novel roles for circFLNA in GBM and indicated that the circFLNA/miR-199-3p signaling axis may serve an important role in GBM progression. Therefore, circFLNA may represent a novel target for the diagnosis and treatment of GBM. [ABSTRACT FROM AUTHOR]

Most river-deltas of the world have been extremely altered by anthropic activities, where a regime shift from net accretion into net erosion may have occurred. In this study, subtidal morphodynamic variations in the Yangtze Estuary (YE) are elaborately analyzed for their causalities using high resolution DEM data from bathymetric surveys conducted every two years from 2007 to 2019; sediment budgetary balance in the estuary has been updated accordingly with mean annual depositional/erosional sediment amounts. The results show that subtidal channel erosion has occurred almost over the whole YE with a mean annual erosional rate of −5.59 cm/yr during the study period. Peak erosion occurred both in the South Branch and the delta front with mean annual erosional rates of −12.64 cm/yr and −8.11 cm/yr, respectively. The erosion lessened in the middle estuary where sandy shoals prevail, and a net accretive rate of 3.13 cm/yr was solely measured at the Chongming shoal. Negative correlation between estuarine erosional volume and riverine sediment discharge demonstrates the great impact of upstream hydro-engineering projects on estuarine morphodynamic change, but large-scale estuarine engineering projects also exert remarkable influence on local morphodynamics, evidenced by the presence of deep erosional belts near the projects. Annually eroded sediment amounts were estimated as 166 Mt/yr and 206 Mt/yr in the distributary channels and the delta front during the period 2007–2019, and the former was almost offset by recent sand mining amount of 143 Mt/yr from the distributary channels for land reclamation. Moreover, contemporary eroded sediment mass and sand mining amount from the tidal river reach between Datong and Xuliujing were reckoned as 77 Mt/yr and 44 Mt/yr, respectively. Our analysis further show that recently 124 Mt/yr and 153 Mt/yr of sediment discharge into the tidal river reach at Datong station and the YE at Xuliujing station account for merely 27.5% and 37.7% of their corresponding values before the 1990s, respectively. Annual sediment amount bypassing the estuary into the open sea has decreased by 37.8% from pre-1990s 370 Mt/yr to recent 140 Mt/yr, leading to recently severe erosion in the delta front. It is therefore highlighted that the estuarine system in response to natural and anthropogenic pressures is very dynamic, and the impacts of various engineering projects in the source-to-sink system should be fully taken into consideration when predicting its morphodynamic response in the estuary. • Subtidal morphodynamic change is intensively examined over the entire Yangtze Estuary. • Estuarine eroded sediment and sand mining amounts both exceed recent river sediment discharge. • Cumulative effect of estuarine engineering projects potentially overtakes upstream engineering projects. • Sediment budget model in the YE is revisited for the highly altered S2S regime. [ABSTRACT FROM AUTHOR]

Subaqueous micro-topographic evolution and riverbed deformation have a direct impact on the safety of engineering projects in rivers, estuaries, and coastal environments. However, the relationship between micro-topographic evolution and riverbed deformation in strong tidal environments requires further study; therefore, this study collected high-resolution bathymetry data of the JinShan Deep Trough (JSDT), Hangzhou Bay, from 2013 to 2017 to interpret this relationship using a multi-beam echo sounder. Velocity data and sediment samples were used to simultaneously analyze the dynamic sedimentary environment. The results show that the strong tidal environment, with a maximum velocity of 1.89 m s−1 and a median riverbed sediment grain size of 9.89–25.21 μm, led to vigorous riverbed deformation in the JSDT. Riverbed deformation occurred via erosion in 2013–2015 (12.18 × 106 m3), deposition in 2015–2016 (2.28 × 106 m3), and erosion in 2016–2017 (4.17 × 106 m3) over an area of 21.64 km2. Overall, the JSDT underwent scouring from 2013 to 2017, corresponding to a total volume of 14.17 × 106 m3 or 1.97 million metric tons of sediment, assuming a bulk density of 1.4 t/m3 for riverbed material. Various types of micro-topography were observed in the JSDT, including scour troughs, collapse landforms, gullies, scarps, dunes, and pockmarks. According to correlation analysis of the development and evolution of micro-topographies and large-scale riverbed deformation, active micro-topographies (including dunes and pockmarks) indicated riverbed deposition, whereas stable micro-topographies (including scour troughs, gullies, scarps, and a smooth riverbed) indicated erosion. Deposition thickness was related to the scale and number of active micro-topographies. Furthermore, a reclamation project changed the flood current, which intensified erosion of the JSDT. Therefore, the development and evolution of micro-topographies can be used as indicators of riverbed deformation trends. These results are also applicable to other estuaries and coasts in similar strong tidal environments. • Multi-beam echo sounding used to observe the topography of the JinShan Deep Trough. • Relationship between micro-topographies and riverbed deformation studied. • Changes in morphological parameters and area used to classify micro-topographies. • Dunes and pockmarks in the area were active micro-topographies. • JSDT underwent erosion from 2013 to 2017, with a total erosion volume of 1.97 million MT. [ABSTRACT FROM AUTHOR]