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Background Myocardial dysfunction is an important adverse factor of hemorrhagic shock that induces refractory hypotension, and post-hemorrhagic shock mesenteric lymph (PHSML) return is involved in this adverse effect. This study investigated whether mesenteric lymph drainage (MLD) improves PHSML return-induced cardiac contractile dysfunction via the restoration of cardiomyocyte calcium sensitivity. Materials and methods A hemorrhage shock model was established by using a controlled hemorrhage through the femoral artery that maintained a mean arterial pressure of 40 ± 2 mmHg for 3 h. MLD and mesenteric lymph duct ligation (MLDL) were performed from 1 to 3 h during hypotension. The papillary muscles of the heart were collected for measurement of calmodulin expression and for determining contractile responses to either isoprenaline or calcium. Results The results showed that either MLD or MLDL reversed the hemorrhagic shock-induced downregulation of calmodulin expression, a marker protein of cardiomyocyte calcium sensitization, in papillary muscles. MLD also improved the decreased contractile response and ±df/dt of the papillary muscle strip to gradient isoprenaline or calcium caused by hemorrhagic shock. Conclusion These findings indicate that increased cardiac contractibility may be associated with the restoration of calcium sensitivity produced by PHSML drainage.

ObjectiveThe mechanisms by which exposure of the late-stage progenitor cells to the anesthesia sevoflurane alters their differentiation are not known. We seek to query whether the effects of sevoflurane on late-stage progenitor cells might be regulated by apoptosis and/or autophagy.MethodsTo address the short-term impact of sevoflurane exposure on granule cell differentiation, we used 5-bromo-2-deoxyuridine (BrdU) to identify the labeled late-stage progenitor granule cells. Male or female rats were exposed to 3% sevoflurane for 4 h when the labeled granule cells were 2 weeks old. Differentiation of the BrdU-labeled granule cells was quantified 4 and 7 days after exposure by double immunofluorescence. The expression of apoptosis and autophagy in hippocampal dentate gyrus (DG) was determined by western blot and immunofluorescence. Western blot for the expression of NF-κB was used to evaluate the mechanism. Morris water maze (MWM) test was performed to detect cognitive function in the rats on postnatal 28–33 days.ResultsExposure to sevoflurane decreased the differentiation of the BrdU-labeled late-stage progenitor granule cells, but increased the expression of caspase-3, autophagy, and phosphorylated-P65 in the hippocampus of juvenile rats and resulted in cognitive deficiency. These damaging effects of sevoflurane could be mitigated by inhibitors of autophagy, apoptosis, and NF-κB. The increased apoptosis could be alleviated by pretreatment with the autophagy inhibitor 3-MA, and the increased autophagy and apoptosis could be reduced by pretreatment with NF-κB inhibitor BAY 11-7085.ConclusionThese findings suggest that a single, prolonged sevoflurane exposure could impair the differentiation of late-stage progenitor granule cells in hippocampal DG and cause cognitive deficits possibly via apoptosis activated by autophagy through NF-κB signaling. Our results do not preclude the possibility that the affected differentiation and functional deficits may be caused by depletion of the progenitors pool.

Recently, a new handheld ultrasound-based device, called Accuro, has been commercialized with a real-time automated interpretation of lumbar ultrasound images. We hypothesized that the handheld ultrasound device would improve the efficacy and safety of combined spinal-epidural anesthesia (CSEA) for cesarean delivery in obese parturients.Eighty parturients with a body mass index 30 kg∙mCompared to the palpation group, the first insertion success rate was significantly higher (72.5% vs. 40.0%; P = 0.003), and time taken to identify the needle puncture site was less (30 [26-36] vs. 39 [32-49] seconds; P = 0.001) in the ultrasound group. The rate of parturients who required needle redirections (40.0% vs. 72.5%; P = 0.003) and the incidence of paresthesia were both lower (7.5% vs. 45.0%; P 0.001). The other outcomes had no significant difference between groups. The mean difference between the epidural depth measured by the handheld ultrasound and needle depth was - 0.29 cm [95% limit of agreement, - 0.52 to - 0.05].Our study suggests using the Accuro ultrasound device can enhance the efficacy and safety of CSEA in obese parturients when executed by experienced anesthesiologists, and its automated estimation of epidural depth is accurate.

Soil is composed of particles of various sizes. Once some particles are removed in a physical or chemical process, the particle contacts and soil microstructure will change, leading to irre...

Objective Patients undergoing carotid endarterectomy (CEA) have a significant possibility of developing postoperative cognitive decline (POCD). POCD after surgery could be result from cerebral hypotension induced by cross-clamping or postoperative hyperperfusion. Optic nerve sheath diameter (ONSD) exhibits an excellent correlation with invasive intracranial pressure monitoring, Here, the authors explored the risk factors of POCD in patients undergoing CEA, paying close attention to ONSD to test the hypothesis that decrease of coronal ONSD was related to the incidence of POCD. Design Observational retrospective review. Setting Single tertiary academic center. Participants One hundred sixteen patients undergoing CEA from January 1, 2019 to December 31, 2019. Intervention None. Measurements and Main Results A multivariate logistic regression, scatter diagrams, and a receiver operating curve were used to evaluate the ability to predict POCD though the change in coronal ONSD. This study ultimately enrolled 84 patients and the incidence of POCD within postoperative two days was 28.6%. Decrease of coronal ONSD (odds ratio [OR], 0.438; 95% confidence interval [CI] 0.217-0.881; p = 0.021) and total intravenous anesthesia (TIVA) (OR, 25.541, 95% CI 2.100-310.614, p = 0.011) were independent risk factors for POCD. Changes in coronal ONSD had an area under the curve to distinguish POCD of 0.716 (95% CI 0.531-0.902). Using a cutoff of 0.05 cm, changes of coronal ONSD had a sensitivity of 66.7% and specificity of 66.7%. Conclusions Decrease of coronal ONSD, measured by ultrasonography and TIVA, were associated with POCD. Change in coronal ONSD was a moderate predictor of incidence of POCD.

Background Catechins, caffeine, and theanine as three important metabolites in the tea leaves play essential roles in the formation of specific taste and shows potential health benefits to humans. However, the knowledge on the dynamic changes of these metabolites content over seasons, as well as the candidate regulatory factors, remains largely undetermined. Results An integrated transcriptomic and metabolomic approach was used to analyze the dynamic changes of three mainly metabolites including catechins, caffeine, and theanine, and to explore the potential influencing factors associated with these dynamic changes over the course of seasons. We found that the catechins abundance was higher in Summer than that in Spring and Autumn, and the theanine abundance was significantly higher in Spring than that in Summer and Autumn, whereas caffeine exhibited no significant changes over three seasons. Transcriptomics analysis suggested that genes in photosynthesis pathway were significantly down-regulated which might in linkage to the formation of different phenotypes and metabolites content in the tea leaves of varied seasons. Fifty-six copies of nine genes in catechins biosynthesis, 30 copies of 10 genes in caffeine biosynthesis, and 12 copies of six genes in theanine biosynthesis were detected. The correlative analysis further presented that eight genes can be regulated by transcription factors, and highly correlated with the changes of metabolites abundance in tea-leaves. Conclusion Sunshine intensity as a key factor can affect photosynthesis of tea plants, further affect the expression of major Transcription factors (TFs) and structural genes in, and finally resulted in the various amounts of catechins, caffeine and theaine in tea-leaves over three seasons. These findings provide new insights into abundance and influencing factors of metabolites of tea in different seasons, and further our understanding in the formation of flavor, nutrition and medicinal function.

Many high-piled wharves were built in the last century, and some wharf members have been damaged over decades of operation. It is important to use effective means to evaluate the safety sta...

We aimed to determine whether heart rate variability (HRV) was correlated to long-term outcome in patients who received mechanical thrombectomy (MT) under general anesthesia for emergent large vessel occlusion (ELVO). Data from 106 patients receiving MT under general anesthesia to treat ELVO between January 1, 2017 and December 31, 2019 were collected in a multicenter chart review. Univariate analysis, Chi-square test, and bivariate logistic regression were performed to assess the correlations between preoperative risk factors such as HRV and long-term outcome (as indicated by the modified Rankin score [mRS] at 90 days after MT). Bivariate logistic regression revealed that decreased LF/HF (low frequency/high frequency in HRV) ratio was correlated with unfavorable functional outcome as indicated by mRS ≥ 2 (odds ratio [OR], 0.650; 95% confidence interval [CI], 0.157–0.839; p = 0.018), and functionally dependent outcome as indicated by mRS ≥ 3 (OR, 0.704; 95% CI, 0.360–0.914; p = 0.021). It was also found that ELVO in the right anterior circulation was correlated with lower LF/HF ratio, as compared with ELVO in the contralateral side (p < 0.05). Our retrospective study demonstrated that worse outcome in patients with ELVO who received MT under general anesthesia induced autonomic changes and that decreased LF/HF ratio.

B cell hyperactivities are involved in the development of systemic lupus erythematosus (SLE). Toll-like receptor 7 (TLR7) in the B cells plays a pivotal role in the pathogenesis of SLE. Previous studies have focused on the intrinsic role of B cells in TLR7/MyD88 signaling and consequently on immune activation, autoantibody production, and systemic inflammation. However, a feasible treatment for this immune disorder remains to be discovered. The in vitro cellular response that have been studied likely plays a central role in the production of some important autoantibodies in SLE. We successfully used R848 to build a lupus-like B cell model in vitro; these B cells were overactivated, differentiated into plasma cells, escaped apoptosis, massively proliferated, and produced large amounts of autoantibodies and cytokines. In the present study, we found that TJ-M2010-5, a novel MyD88 inhibitor previously synthesized in our lab, seemed to inhibit the lupus-like condition of B cells, including overactivation, massive proliferation, differentiation into plasma cells, and overproduction of autoantibodies and cytokines. TJ-M2010-5 also induce B cells apoptosis. Furthermore, TJ-M2010-5 was found to remarkably inhibit NF-κB and MAPK signaling. In summary, TJ-M2010-5 might correct R848-induced lupus-like immune disorders of B cells by blocking the TLR7/MyD88/NF-κB and TLR7/MyD88/MAPK signaling pathways.

Background Oxidative stress mediates the nerve injury during the pathogenesis of Alzheimer’s disease (AD). Protecting against oxidative stress damage is an important strategy to prevent and treat AD. Di-Huang-Yi-Zhi (DHYZ) is a Chinese medicine used for the treatment of AD, but its mechanism remains unknown. This study is aimed to investigate the effect of DHYZ on H2O2 induced oxidative damage in PC12 cells. Methods PC12 cells were treated with H2O2 and DHYZ. Cell proliferation was detected by Cell counting kit-8 (CCK-8) assay. Cytotoxicity of H2O2 was measured by lactate dehydrogenase (LDH) release assay. Apoptosis were identified by Annexin V-FITC/PI staining. Caspase 3 activity was detected by commercial kit. Mitochondrial membrane potential (MMP) was detected by JC-1 staining. Reactive oxygen species (ROS) was 2′, 7′-Dichlorodihydrofluorescein diacetate (DCFH-DA) staining. Protein expression and phosphorylation was identified by western blot. Results The results showed that DHYZ antagonized H2O2-mediated cytotoxicity and proliferation inhibition. DHYZ reduced ROS production, stabilize mitochondrial membrane potential, inhibit Caspase-3 activity and apoptosis induced by H2O2. In addition, DHYZ inhibited the phosphorylation of ASK1, JNK1/2/3 and p38 MAPK which were up-regulated by H2O2. Conclusions The present study suggested that DHYZ protected PC12 cells from H2O2-induced oxidative stress damage and was related to inhibition of ROS production and ASK1-JNK/p38 MAPK signaling. The present study provides experimental evidence for the application of DHYZ for the management of oxidative stress damage and AD.

Carbon monoxide‑releasing molecule‑3 (CORM‑3), which is an exogenous carbon monoxide (CO) compound, slowly releases CO under physiological conditions; this exerts neuroprotective effects against incomplete ischemia/reperfusion injury. The objective of the present study was to investigate whether the administration of CORM‑3 protects against nucleotide‑binding oligomerization domain‑like receptor pyrin domain‑3 (NLRP3) inflammasome formation and neuronal pyroptosis in the hippocampus following hemorrhagic shock and resuscitation (HSR). To establish this, an HSR model was created. Hemorrhagic shock was induced in adult male Sprague‑Dawley rats under sevoflurane anesthesia by bleeding using a heparinized syringe to maintain a mean arterial pressure of 30±5 mmHg for 60 min. Resuscitation was performed by reperfusion of the blood and, if necessary, administering sterile saline to achieve the baseline arterial pressure. Following resuscitation, CORM‑3 (4 mg/kg) was injected via the femoral vein. Neuronal pyroptosis in the hippocampus, mitochondrial morphology, mitochondrial DNA (mtDNA), brain magnetic resonance imaging, expression levels of NLRP3 and the interaction of pro‑caspase‑1 and apoptosis‑associated speck‑like protein containing a CARD domain (ASC) were examined 12 h after HSR; locomotor activity was assessed 7 days after HSR. Compared with HSR‑treated rats, CORM‑3 administration resulted in a lower level of neuronal pyroptosis in the hippocampus, improved mitochondrial morphology, a lower mtDNA level, steadier levels of metabolites, decreased expression levels of NLRP3 and pro‑caspase‑1 interacting with ASC and enhanced locomotor activity. In conclusion, treatment with CORM‑3 ameliorated impairments of locomotor and exploratory activities in a rat model of HSR. The mechanism may be associated with the inhibition of mitochondrial DNA‑induced pyroptosis via improvements in cell metabolism.

Landslides threaten the safety of vehicles on highways. Nevertheless, a rigorous quantitative highway landslide risk assessment seems difficult. Using a case study in Hong Kong, this paper presents a method for quantitative risk assessment for highway landslides. The suggested method consists of three parts, i.e., analysis of annual failure probability of the slope, the spatial impact analysis and the consequence analysis. In the case study, the annual failure probability of the slope is analyzed based on historical failure data in Hong Kong. The spatial impact of the landslides is estimated based on empirical correlations with the geometry of the slope. The consequence is assessed based on probabilistic modeling of the traffic on the highway. Based on the suggested method, the annual failure probability of the slope, the distance from the slope and the road and the density of vehicles on the road can significantly affect the landslide risk and the suggested method can be used to quantify the effects of these factors. The suggested method can be also potentially used to analyze the highway landslide risk in other regions.

Barriers are commonly used to intercept landslide flows or debris flows. The presence of a barrier changes the flow condition and leads to a buildup of earth pressure in a zone behind the b...

Objective. To explore the ability of asiatic acid to interfere with the invasion and proliferation of breast cancer cells by inhibiting WAVE3 expression and activation through the PI3K/AKT signaling pathway. Methods. The MDA-MB-231 cells with strong invasiveness were screened by transwell assay, and plasmids with high expression of WAVE3 were constructed for transfection. The transfection effect and protein expression level of plasmids were verified by PCR and WB. The effects of asiatic acid on cell proliferation and invasion were investigated by flow cytometry. The xenografted tumor models in nude mice were established to study the antitumor activity of asiatic acid. Results. Asiatic acid significantly inhibited the activity of MDA-MB-231 cells, and the expression level of WAVE3 increased significantly in the tissue of ductal carcinoma in situ and was lower than that in the metastasis group. After plasmid transfection, the mRNA and protein expression of WAVE3 increased significantly in the cells. Asiatic acid at different concentrations had an impact on cell apoptosis and invasion and could significantly inhibit the expression of WAVE3, P53, p-PI3K, p-AKT, and other proteins. The T/C(%) of asiatic acid (50 mg/kg) for MDA-MB-231(F10) xenografted tumor in nude mice was 46.33%, with a tumor inhibition rate of 59.55%. Asiatic acid could significantly inhibit the growth of MDA-MB-231 (F10) xenografted tumors in nude mice (p<0.05). Conclusions. Asiatic acid interferes with the ability of breast cancer cells to invade and proliferate by inhibiting WAVE3 expression and activation and the mechanism of action may be related to the PI3K/AKT signaling pathway.

Flood damage has been extremely severe in recent decades and is responsible for a greater number of damaging events than any other type of natural hazard. Floods are anticipated to happen more frequently in the future because of climate change, unplanned rapid urbanization, change in land use pattern, poor watershed management and declining recharge of groundwater by extension of impermeable surfaces in urban areas. Therefore, assessment of flood consequence under large storms is an important issue. This paper quantifies the elements at risk in Hong Kong under large storm scenarios with rain intensities of 29 and 85% of the 24-h Probable Maximum Precipitation (PMP). The buildings affected were obtained by overlaying flood maps and building maps in a GIS environment. The numbers of buildings of all types and exposed individuals affected by the flood under the two storm scenarios were also quantified. The results indicate that residential buildings appear to be the most vulnerable among all structures and facilities in Hong Kong and thereby may lead to the highest affected population under the two rainfall scenarios. The western part of Hong Kong Island is more susceptible to flooding as a result of its steeper slope terrain and densely populated infrastructures. Enhanced flood risk assessment methods and improved understanding about flood risk will support decision makers in decreasing damage and fatalities.

The break of large landslide dam will trigger catastrophic flood hazard to the downstream area. To manage the flood risk, multiple mitigation measures are required, such as evacuation and removal of obstacles in the river channel. Design of these mitigation measures relies on the estimation of critical flood parameters, namely, peak discharges and stages along the river. However, uncertainties in outburst flood prediction and flood routing analysis have significant influence on the estimation of these flood parameters. Ignoring these uncertainties will undermine the reliability of the estimated flood parameters, which might lead to insufficient design of risk mitigation measures. To enhance the reliability of landslide dam break risk management, we quantify the influence of uncertainties in both landslide dam material erodibility and river channel roughness on the estimation of flood parameters. Successive Baige landslide dams on the Jinsha River in 2018 are investigated to show how the uncertainty quantification facilitates robust decision making for risk management.

A drum centrifuge accommodates a long soil model in its drum, hence models distributed geotechnical problems better than a beam centrifuge. A modular package has been designed for the HKUST 870 g-ton drum centrifuge to simulate overtopping and erosion of embankment dams. For the sake of space-saving and convenient operation, 1/6 of the drum model channel is designed as a fluid storage tank. The fluid storage tank is sealed by a top cover, and controlled by a fixed baffle and a movable baffle driven by a three-dimensional centrifuge actuator. After the drum centrifuge spins to the design speed, the movable baffle can be lifted by the actuator to release the fluid into the reservoir of the embankment. The rising rate of the water level can be controlled by adjusting the lifted height of the baffle. The embankment can then be overtopped. High-speed cameras and a PICV system will be employed to monitor the erosion or break process of the embankment. Pore pressure sensors are installed inside the embankment to measure the pore pressure response.

Landslide dams are typically formed by loose landslide deposits which can be vulnerable to overtopping failure. Subsequent flash flood can pose great threat to downstream area. Hong Kong is subject to subtropical weather and the terrain is hilly. Due to the changing climate, extreme rainfall is becoming more and more frequent which can cause a large number of landslides. Therefore, it is essential to evaluate possible landslide dam formation and failure process, especially on Hong Kong Island which is densely populated. In this paper, a physically-based distributed cell model, EDDA 2.0, is adopted which is capable to predict rainfall-induced landslides, debris flows, erosion and deposition process, and flash floods. Possible landslide dam formation and failure are predicted under an extreme rainfall condition (65% of the 24-h PMP, Probable Maximum Precipitation). Although the magnitude of the landslide and the landslide dam is not very large, the subsequent flash flood can pose much greater threat to people’s lives and properties especially in urban area such as Hong Kong Island where the population density is rather high.

Loss of fine particles or suffusion in soils induced by seepage is an important problem that may cause dam or dike failures. This paper aims to study the evolution mechanisms of suffusion i...

With global warming, glacial collapse chain disasters have frequently occurred in high-mountain areas. In particular, the ice avalanche-glacial debris flow/landslide-barrier lake-flood burst chain disaster caused the most serious consequences. Different from the general landslide dam consisted of rocks and soils, the landslide dam initiated by ice avalanches contains a considerable amount of ice. The appearance of ice will influence the overall performance of the landslide dam by melting, which may cause differential settlements, local weak zones, a more porous structure, and a lower erosion resistance of the landslide dam. Such changes in the erodibility and geometry of the landslide dam will further affect the dam overtopping and flood routing process, which have not been investigated yet and urgently require further study. Therefore, in this study, a preliminary study of the effects of different ice fractions of the landslide dam is conducted, which mainly involves changes in the dam erodibility, the dam geometry, the overtopping development, the final breach size, the process of downstream flood routing, etc. Results show that with the increasing amount of ice melting, the coefficient of soil erodibility and the soil void ratio increase significantly, implying a more erodible dam material and a looser dam structure. The melting of ice can also induce obvious dam settlement, which further results in an earlier dam burst and a shorter rescue time. With the increasing initial ice amount in the landslide dam, the overtopping process develops more rapidly, the breach expands greater both horizontally and vertically, the subsequent flood becomes larger, and the peak arrival time comes earlier.

The tidal volume setting as well as colloid transfusion during the peri-operative period after intracranial aneurysm is controversial. A multicenter retrospective study was conducted to determine whether or not an increased tidal volume setting and colloid transfusion are associated with poor outcomes and postoperative pulmonary complications after intracranial aneurysm.Data from endovascular coiling to treat intracranial aneurysms that took place between 30 March 2014 and 30 March 2016 were collected in a multicenter chart. The primary outcomes were better (defined as a Modified Rankin scores [MRS] ≤2) and worse outcomes (MRS ≥3). Secondary outcomes included pneumonia and non-pneumonia in patients with intracranial aneurysms. Univariate analysis, bivariate logistic regression, Spearman correlation, and a linear regression model were performed to account for the association between peri-operative risk factors and different outcomes.Bivariate logistic analysis showed that worse outcomes were correlated with height, Hunt and Hess scores (HHS), and Fisher grade (P 0.05). There was no significant association between colloid transfusion and worse outcomes and postoperative pneumonia (P 0.05). Postoperative pneumonia incidence was associated with increased height in a population with intracranial aneurysms (P 0.05). The Spearman correlation and a linear regression model suggested that increased height was significantly correlated with lower tidal volume setting (per unit of body weight; P 0.05).Decreased tidal volume with increased height, but not colloid transfusion, was independently associated with worse outcomes and postoperative pneumonia across a spectrum of risk profiles. These findings may help to improve practice decisions regarding tidal volume settings.

In shallow eutrophic lakes, benthic bioclastic deposits accumulate abundant organic carbon derived from macrophyte detritus. Taking the typical macrophyte-dominated Xukou Bay as the study area, field investigations were performed using sediment cores to evaluate benthic phytodetritus accumulation. Specifically, nutrient contents, TOC/TN ratios, pigmentation, and biodegradable compounds were measured as descriptive parameters. The results show that the benthic bioclastic deposit had accumulated abundant pigments, nutrients, and biodegradable compounds derived from macrophytes detritus. These were mainly localized in the top 15 cm of sediments. Nitrogen loading in the sediments was significantly higher than phosphorous loading, with a distinct spatial difference; the total nitrogen content ranged from 127.2-2092.8 mg·kg

Oxidative stress mediates the nerve injury during the pathogenesis of Alzheimer's disease (AD). Protecting against oxidative stress damage is an important strategy to prevent and treat AD. Di-Huang-Yi-Zhi (DHYZ) is a Chinese medicine used for the treatment of AD, but its mechanism remains unknown. This study is aimed to investigate the effect of DHYZ on HPC12 cells were treated with HThe results showed that DHYZ antagonized HThe present study suggested that DHYZ protected PC12 cells from H

An assessment of soil properties at unsampled locations is a common requirement during the design of a geotechnical structure/system. Such an assessment is challenging due to inherent soil variability and the limited number of in situ tests currently available. Here we present a three-dimensional conditioned random field approach for the estimation of anisotropic soil resistance at unsampled locations based only on data from a limited number of cone penetration tests (CPT). The novelty of this work is that the measured CPT data at arbitrary locations can be combined with random field theory to update the estimated soil properties in three dimensions. The accuracy of the estimation can be improved significantly using the proposed method. A case study in Australia is conducted to illustrate the procedure and to assess the capability of the method. The results indicate that the mean values of the conditioned random fields are good estimates of the soil resistance at unsampled locations. The prediction error of the normalized cone penetration resistance is about 0.08 when there are only six CPT tests. A unique feature of this method is its ability to obtain high-resolution results of soil properties in three-dimensional space using a limited number of CPT tests.

In this work, 3D discrete element method modeling of drained shearing tests with gap-graded soils after internal erosion is carried out based on published experimental results. The erosion in the model is achieved by randomly deleting fine particles, mimicking the salt dissolving process in the experiments. The present model successfully simulates the stress–strain behavior of the physical test by employing the roll resistance and lateral membrane. The case without erosion shows a strain-softening and dilative response, while strain-hardening and contractive response starts to occur as the degree of erosion increases. The dilative to contractive transition is mainly caused by the increase in void ratio due to the loss of fine particles. The change from dilative behavior to contractive behavior is more abrupt for the specimen with larger fine particle percentage because the soil skeleton is mainly controlled by the fine particles instead of by the coarse soil particles. The transition from “fines in sand” to “sand in fines” might be associated with the rapid increasing in the contacts associated with fine particles in the specimen as the percentage of fine content increases. The erosion scenario based on the hydraulic gradient is also modeled by deleting the fine particles based on the ranking of the contact force. Compared with the scenario based on random deletion, the remaining fine particles for the erosion scenario based on the ranking of contact force are more dispersedly distributed, which might benefit the small strain stiffness but result in a smaller strength. This work provides some insights for better understanding the mechanism behind the internal erosion and the associated stress–strain behavior of soil. The gradient of the critical state line increases with more loss of fine particles denoting that the fine particles are helpful for holding the structure of the soils from larger deformation.

The 2008 Wenchuan earthquake in Sichuan, China triggered numerous landslides in the stricken area. The loose landslide materials retained on mountain slopes and in gullies are prone to reactivation and may transform into debris flows in the rainy season. Nine years after the Wenchuan earthquake, debris flows are still active in Gaojiagou Ravine 16.5 km north of the epicentre. On 14 August 2010, 3 July 2011, 13 July 2013, and 6 July 2016, four large-scale debris flows were triggered by heavy storms in Gaojiagou Ravine. The four debris flows blocked the Minjiang River twice and caused severe damage to nearby villages and reconstruction sites. Several questions arise from these repeated debris flows. Did the level of triggering rainfall change in the four debris flow events? How did the initiation mechanism evolve over time? What are the differences in the runout characteristics in the four events? How did the check dams constructed in 2012 function in the subsequent debris flows? In this paper, we evaluated the loose deposit volumes in Gaojiagou Ravine before and after each of the four debris flows and the runout volumes, and analysed the triggering rainfall intensities, initiation mechanisms and runout characteristics of the four debris flows. The rainfall threshold for the debris flows in Gaojiagou Ravine increased over time, and the initiation mechanisms evolved from landslides to channel-bed failure, and subsequently to channel-bank erosion. The mobility of the debris flows decreased from 2010 to 2016 as the initiation positions moved lower and the particle size of the runout materials became coarser.

Interstitial cells of Cajal (ICC), especially myenteric interstitial cells of Cajal (ICC-MY), are key to gastrointestinal motility. However, their role in the pathogenesis of functional dyspepsia (FD) is unclear. Therefore, autophagy and differentiation of ICC-MY were investigated to elucidate the pathogenesis of gastric motility disorder in FD. FD model was induced by chronic stress via tail clamping in rats, which was assessed by the vital signs of rats, gastric emptying rate result, and histology. The ultrastructure of ICC-MY was examined using transmission electron microscope. In ICC-MY, changes in autophagic biomarkers (Beclin1 and LC3B) and differentiation biomarkers (c-kit and SCF) were evaluated with in situ hybridization, quantitative real time PCR, immunofluorescence, and Western blot, respectively. The FD model was successfully induced in rats, as evidenced by the abnormal vital signs (such as loss of appetite, liquid excreta, less activity, and slower weight gain), the decrease in gastric emptying rates, and little pathological change in gastric antrum tissue. Compared with the control group, FD caused increased organelle denaturation or reduction and increase in vacuolization. FD also promoted generation of autophagosomes in ICC-MY. Moreover, increased the expression of Beclin1 and LC3B, but decreased expression of c-kit and SCF. Excessive autophagy and abnormal differentiation of ICC-MY may contribute to the pathogenesis of gastric motility disorder in FD.

This paper presents a stochastic seismic analysis of geosynthetic-reinforced soil slopes (GRSS) using the probability density evolution method (PDEM). The combination of the uncertainties of seismic ground motions (SGM), soil properties and reinforcement parameters was considered. The stochastic SGM was generated from a random function based on the spectral representation method. The present method is proved to be more precise than the pseudo-static method and pseudo-dynamic method due to the consideration of the uncertainty of frequency spectrum of seismic excitations, and more efficient than the Monte Carlo simulation method for reducing the number of samples by 39 times. Without involving the stochastic earthquake, the result of the estimated performance would incur large errors since it greatly depends on the selected earthquakes, which may be one of the major reasons for GRSS failure. The slope displacement and the reinforcement strain occur at a relatively narrow region at the beginning, then increase and fluctuate intensively with large uncertainty, and finally become steady in the earthquake decay phase. The reinforcement length has a more substantial influence on the failure probability of the reinforcement than other parameters in the studied ranges. The reinforcement strain increases but the slope displacement decreases with the reinforcement length because of the variation of failure mechanisms.

Tapered piles have superior benefits over traditional cylindrical piles in resisting axial and lateral loads, being an economical alternative to cylindrical piles. When designing the tapered pile in soft or liquefiable soil, it is necessary to identify its buckling strengths. Notwithstanding, the buckling analysis of tapered piles considering nonlinear pile-soil interactions with geometric imperfections under combined loads has not been well established. This paper presents a non-prismatic beam-column element for nonlinear buckling analysis, considering nonlinear pile-soil interactions, combined external loads, and geometric imperfections, to robustly and efficiently simulate the buckling response of tapered piles. Unlike the discrete-spring stepped element (DSSE) model using an approximate stepwise modeling approach, analytical expressions for considering the axial and flexural rigidity of tapered section members are derived in the proposed element formulations to explicitly model the tapered sections. Several examples of buckling analysis are provided to validate the accuracy and efficiency of the proposed method. Parametric studies are performed to investigate the influences of Young’s modulus, taper ratio, initial geometric imperfection, and horizontal load on the buckling behavior of tapered piles with different boundary conditions. The critical buckling load of tapered piles is found to increase with increasing Young’s modulus and decreasing initial geometric imperfection and horizontal load. An optimal taper ratio of the tapered pile can be determined to carry the maximum axial load.

In the comproportionation reaction of CuII X2 and Cu0 with isopropylacetylene (iPr-C≡C-H), the ethynediide species C22- is generated via concomitant C-H/C-C bond cleavage of the iPr-C≡C-H precursor under moderate temperature to direct the formation of CuI mixed ethynediide/isopropylethynide nanoclusters (potentially explosive). The active ethynediide dianion C22- exhibits chameleon-like templating behavior to form C2 @Cum (m=6 (3, 4), 7 (2, 4), 8 (1)) central structural units for successive formation of {C22- ⊂Cu24 } (1, 2), {6 C22- ⊂Cu48 } (3), and {18 C22- ⊂Cu92 } (4) complexes. Bearing the highest C22- content, complex 4 features an unprecedented nanoscale Cu2 C2 kernel. Furthermore, 1-3 exhibit structure-controlled photoluminescence in the solid state.

This paper presents a coupled air–water flow analysis to evaluate the performance of a three-layer capillary barrier for controlling water infiltration into and gas emission from a waste containment system in a high precipitation environment, and to optimize combinations of local soil layers for barrier construction. A multi-phase flow model is proposed considering the movements of the gas and water phases simultaneously. The governing partial differential equations are solved in COMSOL Multiphysics software. Several combinations of lean clay with sand (CL), clayey sand with gravel (SC), silty sand with gravel (SM), sandy silt (ML), and well-graded gravel with silt (GW–GM) are examined. The rates of percolation water and gas emission are used as indicators to compare the performance of different combinations. A fine-grained surface soil layer reduces both water infiltration and gas emission due to its low desaturation rate and high water-retention capacity. The coarse middle layer plays a critical role, promoting capillary effects and hindering water infiltration during rainfall as well as draining any infiltrated water or percolated gas.

Current knowledge on responses of aquatic clonal plants to resource availability is largely based on studies manipulating limited resource levels, which may have failed to capture the “big picture” for aquatic clonal plants in response to resource availability. In a greenhouse experiment, we grew the floating clonal plant Spirodela polyrhiza under ten nutrient levels (i.e., 1/64×, 1/32×, 1/16×, 1/8×, 1/4×, 1/2×, 1×, 2×, 4× and 8×full-strength Hoagland solution) and examined their responses in terms of clonal growth, morphology and biomass allocations. The responses of total biomass and number of ramets to nutrient availability were unimodal. A similar pattern was found for frond mass, frond length and frond width, even though area per frond and specific frond area fluctuated greatly in response to nutrient availability. In contrast, the responses of root mass and root length to nutrient availability were U-shaped. Moreover, S. polyrhiza invested more to roots under lower nutrient concentrations. These results suggest that nutrient availability may have distinct influences on roots and fronds of the aquatic clonal plant S. polyrhiza, resulting in a great influence on the whole S. polyrhiza population.

Study region Hong Kong, China. Study focus This paper aims to develop a flood analysis model to integrate the effects of multiple flooding triggers (i.e. rainfall, high sea levels and wave overtopping) during powerful tropical cyclones and investigate coastal flood hazards in an urban area at the street scale. The process of wave overtopping is properly estimated and integrated in a dual-drainage model in a maneuverable way as an inflow discharge hydrograph. The inundation during Typhoon Mangkhut, 2018, in Tseung Kwan O town center, a coastal community of Hong Kong, is taken as a case study. New hydrological insights for the region The inundation scenario in Tseung Kwan O town center during Tyhpoon Mangkhut is reproduced and comparison between different drainage conditions demonstrates the key role of drainage facilities in the mitigation of flooding induced by wave overtopping, although the varying sea level boundary could partly reduce the drainage efficiency. In addition, possible flood scenarios and pedestrian stability in flowing water upon the unfavorable combination of storm surge and astronomical tide, as well as the effectiveness of a 1.1 m wave wall are evaluated. The overtopping discharge, flooding severity and dangerous zones for pedestrian can be markedly reduced by the wave wall.

The functional role of procyanidins (PC) in PM2.5-induced cardiovascular diseases (CVD) is largely unexplored. This study aimed to explore the protective effect of PC against PM2.5-induced vascular smooth muscle cells (VSMCs) apoptosis and underlying mechanisms. Sprague Dawley rats were pretreated with three doses of PC (50, 100, and 200 mg/kg) and exposed to 10 mg/kg PM2.5 by intratracheal instillation three times a week. VSMCs were exposed to 5, 10, and 20 μM PC before the addition of 100 μg/mL PM2.5. In vivo, the PM2.5 exposure induced apoptosis in the thoracic aorta of rats. The PM2.5 exposure significantly elevated the reactive oxygen species (ROS) and malondialdehyde (MDA) levels and decreased the superoxide dismutase activity. Also, PC supplementation increased the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), and its downstream antioxidant genes, i.e., NAD(P)H dehydrogenase (quinine) 1 and heme oxygenase 1, attenuated oxidative stress and vascular apoptosis. In vitro, PM2.5 induced cytotoxicity in VSMCs in a dose-dependent manner. Besides, PC abolished the PM2.5-induced cytotoxicity by activating the Nrf2 signal pathway, alleviating oxidative stress, and decreasing apoptosis. In conclusion, this work is the first study to demonstrate that PC can suppress the PM2.5-induced VSMCs apoptosis via the activation of the Nrf2 signal pathway.

Landslides pose threats to the safety and property of people living in mountainous areas like Hong Kong. Dependence of landslide travel distance on initial conditions and travel routes has broad implications for assessing the landslide risks. In this study, the controlling topographic and geologic factors for travel distances of open hillslope landslides and channelized debris flows are examined based on the Enhanced Natural Terrain Landslide Inventory (ENTLI) in Hong Kong with 11,622 records during the period of 1984–2013. The mean values of the horizontal travel distances of open hillslope landslides and channelized debris flows are 24.1 and 86.3 m, respectively. Correlations combining horizontal travel distances, volumes and fall heights of open hillslope landslides have been derived. The horizontal travel distances (L) and fall heights (H) are closely related for both types of landslides. The use of the L/H ratio alone as a representation of natural terrain landslide mobility is not suggested. Because of the entrainment of loose materials, the travel distances of channelized debris flows are enlarged significantly on colluvium lands (with mean value of 142.6 m), compared with those on weathered mantles (with mean value of 74.2 m).

After the formation of a landslide barrier lake, additional landslides in the lake area can generate huge waves, which may overtop the landslide dam and eventually lead to breaching failure of the dam. Since landslide dams are natural dams without compaction, the dam materials are heterogeneous, loose and highly erodible, so that the breaching process under wave actions is rather complex. Although a number of model tests have been conducted by different workers, several critical issues have not been addressed satisfactorily, including influences of landslide dam materials on breaching characteristics, stability criteria for landslide dams under surge waves, and differences in the breaching mechanisms by surge wave impact and natural overtopping flow. In this study, 9 flume tests were conducted to study the breaching mechanisms of landslide dams composed of fine, medium and coarse materials under surge waves of three wave heights. Compared with the natural overtopping condition, the breaching process under surge wave impact is much faster (the consumed time is only 2%-20%) and the peak discharge of breaching flood is 1.1-5.1 times larger. The surge waves accelerate the landslide dam breaching with more intense surface erosion and larger dynamic pore pressure. The total erosion volume and breaching duration decrease with the increase of mean particle size. With the increase of wave height, both the average erosion rate and peak discharge of the breaching flood increase. An empirical equation of wave climbing height for landslide dams was established based on the flume test results, which considers slope angle, surface roughness of dam and wave characteristics. The net overtopping height, ΔH, which is the difference between the sum of wave climbing height and still water level and the effective dam height, can be adopted as a useful index to preliminarily judge whether the landslide dam is stable or not under the impact of surge waves. When ΔH

The hydraulic conductivity of unsaturated soils can span several orders of magnitude. The measurement of hydraulic conductivity over a wide suction range is a challenging task for decades. In this study, numerical tests are carried out to check the assumption, error sources, and applicable conditions of the wetting front advancing method and instantaneous profile method. Based on the numerical test results, a digital wetting front advancing method is proposed to measure hydraulic conductivity of unsaturated soils in the relative high suction range and the traditional instantaneous profile method is found to be robust in measuring hydraulic conductivity in the low suction range, e.g. for soil with a degree of saturation above 0.9. Further, a combination of the digital wetting front advancing method and the traditional instantaneous profile method is implemented in the same soil column test and leads to an accurate soil hydraulic conductivity function over a wide suction range. The proposed method is applicable to various soil types and the test duration is only 1 ~ 5 days, thus makes the measurement of hydraulic conductivity a routine experiment for unsaturated soil mechanics.

Objective Traumatic brain injury (TBI) induced the gastrointestinal inflammation that is associated with TBI-related morbidity and mortality. Carbon monoxide-releasing molecule (CORM)-3 is a water-soluble exogenous carbon monoxide that exerts protective effects against inflammation-induced pyroptosis. We investigated the gastrointestinal inflammation in a rodent model of traumatic brain injury (TBI) with subsequent hemorrhagic shock and resuscitation (HSR), as well as effects of CORM-3 using an intestinal injection on both gut and brain. Methods Following exposure to TBI plus HSR, rats were administrated with CORM-3 (8 mg/kg) through an intestinal injection after resuscitation immediately. The pathological changes and pyroptosis in the gut were measured at 24 h and 30 day post-trauma. We also assessed the intestinal and cortical CO content, as well as IL-1β and IL-18 levels in the serum within 48 h after trauma. We then explored pathological changes in the ventromedial prefrontal cortex (vmPFC) and neurological behavior deficits on 30 day post-trauma. Results After TBI + HSR exposure, CORM-3-treated rats presented significantly decreased pyroptosis, more CO content in the jejunum, and lower IL-1β, IL-18 levels in the serum at 24 h after trauma. Moreover, the rats treated with CORM-3 exerted ameliorated jejunal and vmPFC injury, enhanced learning/memory ability and exploratory activity, improved anxiety-like behaviors than the TBI + HSR-treated rats on 30 day post-trauma. Conclusion These experimental data demonstrated and bidirectional gut–brain interactions after TBI, anti-inflammatory effects of CORM-3, which may improve late outcomes after brain injury.

Landslide susceptibility assessment is essential for regional landslide risk assessment and mitigation. Most past studies involved cell-based analysis that takes landslide incidents as geo-spatial points. Nevertheless, given that a landslide is a two-dimensional polygon on maps and a three-dimensional object in the real world, an object-wise assessment is more logical. Fusing with artificial intelligence (AI) techniques, this paper proposes a novel AI-powered object-based landslide susceptibility assessment method to address this issue. First, landslide and non-landslide objects are defined based on an optimal object size determined by statistics of historical landslides. Next, landslide and non-landslide samples are constructed by integrating geoenvironmental data layers derived from multi-source data. Subsequently, AI techniques are applied to learn susceptibility prediction based on the prepared samples. To illustrate the proposed method, a comprehensive case study of Hong Kong is conducted, in which six AI algorithms are evaluated including logistic regression (area under curve, AUC = 0.949), random forest (AUC = 0.951), LogitBoost (AUC = 0.958), convolutional neural network (CNN) (AUC = 0.966), bidirectional long short-term memory architecture of recurrent neural network (BiLSTM-RNN) (AUC = 0.966), and CNN-LSTM (AUC = 0.972), among which the BiLSTM-RNN and CNN-LSTM algorithms are applied in landslide susceptibility assessment for the first time. Results confirm that the proposed object-based method outperforms the traditional cell-based method significantly. Equally importantly, the case study produced the first set of AI-based territory-wide landslide susceptibility maps for Hong Kong. These maps can be used as a fundamental tool for quantifying natural terrain landslide risk and identifying susceptible zones where landslide mitigation measures may be needed.

Many coastal cities face growing flood risks due to interactions of multiple triggers related to the changing climate such as intense rainstorms, rising sea level, severe storm surges, etc. The complex urban morphology and infrastructural systems have profound effects on flow routing and need to be properly considered in flood modelling. In particular, the underground drainage system is a key element of urban drainage, but its fine-scale modelling is still an open challenge. This paper aims to evaluate flood hazards in coastal cities upon combined high tide, storm surge and intense rainfall by incorporating the compound weather conditions into a grid-based flood analysis model. An equivalent drainage method is proposed to improve the efficiency of large-scale urban drainage modelling, which simulates the capacity of drainage networks by enhanced infiltration. The equivalent method is calibrated with a physically based drainage model considering varying rainfall intensities and sea levels. The flood hazards in two coastal cities (Shenzhen and Hong Kong) in the Pearl River Delta of South China are evaluated. Results show that in the combination of low-intensity rainfall and high sea level, stormwater is difficult to drain into the sea, and significant backflows into the drainage outfalls can occur. The inland inundation caused by rainfall can be amplified by high sea levels due to the reduction of drainage efficiency. Moreover, flood hazards both along the coastline and in the inland areas can be exacerbated due to sea level rise and ground subsidence. The equivalent drainage method shows a good performance and provides an easy alternative in large-scale urban flood modelling. The predicted hazard scenarios under various combinations of weather conditions provide essential information for re-examining urban drainage designs and developing new flood prevention strategies.

Many cities face high flood risks due to intense rainstorms and dense urban environments. Quantifying the degree and duration of flood impact to urban systems under extreme rainstorms is essential for long-term flood risk management and short-term emergency response. This study aims to develop a novel stress testing framework for evaluating urban system flooding upon extreme rainstorms in Hong Kong. The stress testing framework is based on a pipe-surface coupled hydraulic model for detailed flood simulation in urban settings and a dynamic flood impact evaluation method for assessing interruptions to urban transportation and building systems. The proposed stress testing method is applied to assess the flood impacts in Kowloon, the most densely populated area in Hong Kong. Detailed urban settings such as engineering drainage facilities and buildings are incorporated into the flood simulation model, and the model is validated both qualitatively and quantitatively by field observations. Flood hazard scenarios are investigated under design rainstorms of different return periods (20, 100, and 1000 years), and the impacts on transportation and building systems are evaluated with the new process-based impact evaluation method. The results of the case study indicate that underground mass transit railway (MTR) stations and residential buildings will be more affected than highways and other types of buildings in Kowloon: up to 56% of MTR stations and 43% of residential buildings may be affected under the 1000-year rainstorm, with inundation durations of 8 and 7 h for the MTR stations and residential buildings, respectively. To ensure public transportation services and reduce potential exposure of residents during extreme rainstorms, mitigation measures should be taken to reduce the affected percentage and duration of MTR stations and residential buildings. The proposed methods contribute to enhanced societal flood preparedness, warning, and response.

Rain-induced landslides are recognized as one of the most catastrophic hazards on hilly terrains. To develop strategies for landslide risk assessment and management, it is necessary to estimate not only the rainfall threshold for the initiation of landslides, but also the likely magnitudes of landslides triggered by a storm of a given intensity. In this study, the frequency distributions of both open hillside landslides and channelized debris flows in Hong Kong are established on the basis of the Enhanced Natural Terrain Landslide Inventory (ENTLI) with 19,763 records in Hong Kong up to 2013. The landslide magnitudes are measured in terms of the number, scar area, volume, or density of landslides. The mean values of the scar areas and volumes are 55.2 m2 and 102.0 m3, respectively, for the open hillside landslides and 91.3 m2 and 166.5 m3, respectively, for the channelized debris flows. Empirical correlations between the numbers, scar areas, and volumes of hillside landslides or channelized debris flows and the maximum rolling rainfall intensities of different periods have been derived. The maximum rolling 4- to 24-h rainfall amounts provide better predictions compared with those with the maximum rolling 1-h rainfall. Maximum rolling rainfall intensity-duration thresholds identifying the likely rainfall conditions that yield natural terrain landslides or debris flows of different magnitudes are also proposed. The initiation rainfall thresholds are identified as 75, 90, 100, 120, 150, 180, and 200 mm for the maximum rolling 1-, 2-, 4-, 6-, 8-, 12-, and 24-h rainfall, respectively.

We successfully employed bisphenol A and several different formyl-containing monomers as useful building blocks to construct a series of hydroxy-group-containing porous organic polymers in a sealed tube at high temperature. Fourier transform infrared and solid-state 13C CP/MAS NMR spectroscopy are utilized to characterize the possible structure of the obtained polymers. The highest Brunauer–Emmet–Teller specific surface area of the phenolic-resin porous organic polymers (PPOPs) is estimated to be 920 m2 g–1. The PPOPs exhibit a highest carbon dioxide uptake (up to 15.0 wt % (273 K) and 8.8 wt % (298 K) at 1.0 bar), and possess moderate hydrogen storage capacities ranging from 1.28 to 1.04 wt % (77 K) at 1.0 bar. Moreover, the highest uptake of methane for the PPOPs is measured as 4.3 wt % (273 K) at 1.0 bar.

A series of seven new complexes including silver-thiolate molecular clusters and their covalent supramolecular frameworks have been assembled from the silver carbide precursor Ag2 C2 using a C22- pre-templated approach. Herein, two prototype clusters Ag14 (SR)6 and CO3 @Agm (SR)10 (R=isopropyl, cyclohexyl or tert-butyl; m=18 or 20) are employed to construct cluster-based metal-organic frameworks of different dimensions. In particular, both new ellipsoidal tetradecanuclear molecular cluster compounds, namely, Ag14 (S-iPr)6 (CO2 CF3 )8 ⋅(DMSO)6 (two polymorphic forms 1, 2) and [Ag14 (S-Cy)6 (CO2 CF3 )8 (DMSO)4 ]⋅(DMSO)3 (3), and a cluster-based metal-organic framework {Ag3 [Ag14 (S-iPr)6 (CO2 CF3 )11 (H2 O)3 CH3 OH]⋅(H2 O)2.5 }n (4) have been isolated and structurally characterized. Furthermore, increased acidity of the reaction mixture afforded three carboxylate-templated cluster based frameworks: a chain-like compound {[HN(CH3 )2 CO]⋅[CO3 @Ag18 (S-tBu)10 (NO3 )7 (DMF)4 ]⋅DMF}n (5), as well as two layer-type compounds, namely, {Ag[CO3 @Ag20 (S-iPr)10 (CO2 CF3 )9 (CO2 HCF3 )(CH3 OH)2 ]}n (6) and {Ag2 [CO3 @Ag20 (S-Cy)10 (CO2 CF3 )10 (CO2 HCF3 )2 (H2 O)2 ]⋅(H2 O)3 ⋅(CH3 OH)3 }n (7) exhibiting sql-net characteristics. It is demonstrated that the C≡C2- pre-template, which draws several Ag+ ions together to form the C2 @Agn entity, plays an indispensable role in the syntheses of these compounds. Furthermore, covalent linkage of these nano-sized silver thiolate clusters from one- to three-dimensions revealed enormous potential for the future development of silver cluster-based frameworks.

Coastal wetlands soil organic carbon (SOC) plays an important role in global carbon sequestration, and exotic S. alterniflora affects the coastal ecosystem’s functions including SOC storage (SOCS). We investigated the vertical deep soil SOC distribution (0–300 cm) in Jiangsu salt marsh and estimated its changes. The results show that (1) exotic S. alterniflora increases the SOC, with higher densities (g kg −1 ) in both topsoil and deep soil in its colonized area, and subsequently increases the SOCS vertical depth (cm) distribution. Such influences become more prominent with time since the introduction of S. alterniflora . The deepest SOC distribution (180 cm) and the highest SOC content (2.14 ± 0.19 g kg −1 ) in the deep layer (50–300 cm) were found in the zones where S. salsa – S. alterniflora co-exist (SSI). The vertical SOC distribution in zones where multi-species co-exists is deeper than that in mono-species dominated zones; (2) The deep soil (100–300 cm) SOC accounts more than 50% of 0–300 cm SOC in Jiangsu salt marsh, suggesting that SOC content of deep soil should not be ignored when calculating the global soil carbon stock; (3) Total SOCS within 0–300 cm in Jiangsu salt marshes (107.84 × 10 6 m 2 ) is 84.90 × 10 10 g, of which 0–100 cm, 100–200 cm and 200–300 cm layer accounts for 38.25%, 30.72% and 31.03%, respectively. The size of the SOCS (0–300 cm) in the Jiangsu salt marshes relatively to the global biome (0.36 × 10 −6 ) is in a lower proportion of the range of salt marsh area to global biome area (0.89 × 10 −6 ). The S. alterniflora salt marsh contributes most of the SOCS in the 0–300 cm and 0–100 cm soils.

Heavy rainfall is a key cause of shallow landslides in red-bed terrains with steep topography and residual soils of degradable strength. In this study, laboratory model tests were carried out to examine the characteristics of rainfall infiltration, deformation, and failures of slopes in the red-bed area of Sichuan. The hydrological response and deformation of the slope soil during rainfall are addressed. Based on a modified Green–Ampt infiltration model, ponding along the bedrock surface is incorporated. A physically based model for shallow landslides caused by rainfall is developed. The theoretical analysis and the model test results indicate that the slope failures are related to erosion in the shallow soil layer and rainwater infiltration, particularly along preferential seepage channels. The process of rainfall-induced shallow landslides can be separated into three stages: erosion at the slope toe, tension crack formation at the slope crest, and shallow sliding. When initial underground water level is located at the bedrock surface or the preferential seepage flow quickly reaches the bedrock surface, it is easier for the soil slopes to slide along the bedrock surface than along the wetting front.

This paper presents a computational scheme for simulating debris-flow impact pressures on buildings in urban areas. The debris flow mobility is described using depth-averaged mass and momentum equations considering the erosion and deposition processes and changing solid concentrations. The total impact pressure consists of a dynamic impact pressure from the moving debris flow mixture and a static pressure from the deposited debris material. A target analysis area on Hong Kong Island, including a large number of buildings in that area, is characterized precisely using a three-dimensional high-resolution digital elevation model, and discretized into a grid of 5 m square cells with different bed material parameters. Using the model, the flow patterns of a large debris flow around nearly 20 buildings along the flow path and the impact pressures against the facades of these buildings are simulated. The buildings increase the flow depth and flow velocity as the debris tends to run up and deposit in front of the buildings and the flow path tends to be narrowed due to building blockage. The impact pressures are high on the building facades that face the main traversing path of the debris flow. Deposition of debris in front of the buildings increases the impact pressure.