Deposition Area Research Articles

Ecological and Health Risks from Trace Elements Contamination in Soils at the Rutile Bearing Area of Akonolinga, Cameroon

This study evaluates the concentrations of trace elements (TEs) in soils from the rutile deposit area of Akonolinga, Cameroon, and analyzes the associated health risks. A total of 25 samples were analyzed using flame atomic absorption spectrometry (FAAS). The results show that TE concentrations follow the decreasing order Fe, Ti, Zr, Mn, Cr, V, Ba, Zn, Nb, Ni, Pb, Ga, Cu, Co, Y, Br, and Sn. Pollution indices and the Pearson correlation matrix reveal moderate correlations between Fe and several other TEs, indicating a common origin. Enrichment Factors show significant enrichment in Zr, Nb, and Ti, with notable enrichment in Cr and Co at certain sites. Although the Geo-Accumulation Index indicates no direct contamination and the overall ecological risk is low, the Contamination Factor reveals high levels for Cr, Nb, Ti, and Zr. The carcinogenic risk is moderate, while non-carcinogenic risks are high for children and considerable for adults. These research highlight the potential public health impacts in this mining region and provide essential baseline data for future environmental risk management.

Exploring subaqueous bedforms and its relation to hydrodynamics in the Rio Grande Rise, Southwestern Atlantic

This study investigates the interplay between hydrodynamics, sediment dynamics, and topography in the Rio Grande Rise (RGR) area. It addresses bedforms found in five different regions, attributing their formation to the interaction between unconsolidated carbonatic substrate and bottom currents, particularly the M2 tidal flow, the primary lunar semidiurnal constituent. The bedforms are shaped by the interplay of the M2 tidal current and local topography, with the bottom mean flow also contributing to specific areas. Generally, bedforms are classified as subaqueous dunes/tidal banks. The environmental sectorization within the RGR, driven by variations in bottom velocities related to flow-topography interaction, delineates deposition and non-deposition areas. Bathymetric data reveal that bedforms are present in shallower, lower-flow energy zones, whereas FeMn crusts are located in more profound, higher-flow energy areas. They indicate that carbonate sediments are either being transported away from the crust regions or remobilized, leading to accumulation in the areas with bedforms. The flow velocity in FeMn crust areas is able to cause sediment bypassing, resulting in areas where deposition does not occur. Furthermore, these velocities exceed the optimal flow conditions for FeMn crust precipitation and could be eroding the previously formed FeMn crusts. These findings imply that FeMn crusts lie beneath the subaqueous dunes to some extent. This study highlights the complexity of the interaction of oceanic flow with the RGR substrate and its morphology, emphasizing the importance of local hydrodynamics and topography when analyzing these features.

Activation of Ms 6.9 Milin Earthquake on Sedongpu Disaster Chain, China with Multi-Temporal Optical Images

In recent years, disaster chains caused by glacier movements have occurred frequently in the lower Yarlung Tsangpo River in southwest China. However, it is still unclear whether earthquakes significantly contribute to glacier movements and disaster chains. In addition, it is difficult to measure the high-frequency and large gradient displacement time series with optical remote sensing images due to cloud coverage. To this end, we take the Sedongpu disaster chain as an example, where the Milin earthquake, with an epicenter 11 km away, occurred on 18 November 2017. Firstly, to deal with the cloud coverage problem for single optical remote sensing analysis, we employed multiple platform optical images and conducted a cross-platform correlation technique to invert the two-dimensional displacement rate and the cumulative displacement time series of the Sedongpu glacier. To reveal the correlation between earthquakes and disaster chains, we divided the optical images into three classes according to the Milin earthquake event. Lastly, to increase the accuracy and reliability, we propose two strategies for displacement monitoring, that is, a four-quadrant block registration strategy and a multi-window fusion strategy. Results show that the RMSE reduction percentage of the proposed registration method reaches 80%, and the fusion method can retrieve the large magnitude displacements and complete displacement field. Secondly, the Milin earthquake accelerated the Sedongpu glacier movement, where the pre-seismic velocities were less than 0.5 m/day, the co-seismic velocities increased to 1 to 6 m/day, and the post-seismic velocities decreased to 0.5 to 3 m/day. Lastly, the earthquake had a triggering effect around 33 days on the Sedongpu disaster chain event on 21 December 2017. The failure pattern can be summarized as ice and rock collapse in the source area, large magnitude glacier displacement in the moraine area, and a large volume of sediment in the deposition area, causing a river blockage.

Fanya Juu terraces improve soil properties of cultivated land in erosion-prone semi-arid area of Ethiopia

Soil erosion is a major process that affect soil fertility and agricultural productivity. To reduce soil erosion by water, physical soil and water conservation measures such as Fanya juu have been widely introduced. However, the study on the performance of those measures against its target is limited. Objective of this study was to assess the effects of physical soil and water conservation (SWC) measures (e.g., Fanya juu) on selected soil physico-chemical properties. Soil samples were collected at 0–20 cm depth of fields treated with Fanya juu and non-treated (without any physical SWC) and analyzed following standard laboratory procedures. Paired sample t-test and one-way ANOVA were used to analyze data. The results of the analysis revealed that clay, silt, sand, soil pH, soil organic carbon (SOC), total nitrogen (TN), available phosphorous (Pav.), and available potassium (Kav.) differed significantly (p < 0.05) between 8-years conserved and non-conserved land. This could be due to the positive effect of conservation measures in reducing erosion. In addition, in the intra- Fanya juu areas clay, sand, Kav., TN, and SOC were significantly varied (p < 0.05), with greater clay, SOC and nutrients at above Fanya juu (deposition area) than below Fanya juu (loss zone), which can be due to the downward movement of organic matter and surface soil and the protection ability of Fanya juu against erosion. In erosion-prone areas, lacking physical SWC measures could degrade essential soil properties as compared to farm fields with physical SWC measures. The spatial variation in intra-Fanya juu area should be amended by integrating additional soil fertility management practices for better effect.

Prediction of Thrombus Formation within an Oxygenator via Bioimpedance Analysis.

Blood clot formation inside the membrane oxygenator (MO) remains a risk in extracorporeal membrane oxygenation (ECMO). It is associated with thromboembolic complications and normally detectable only at an advanced stage. Established clinical monitoring techniques lack predictive capabilities, emphasizing the need for refinement in MO monitoring towards an early warning system. In this study, an MO was modified by integrating four sensor fibers in the middle of the hollow fiber mat bundle, allowing for bioimpedance measurement within the MO. The modified MO was perfused with human blood in an in vitro test circuit until fulminant clot formation. The optical analysis of clot residues on the extracted hollow fibers showed a clot deposition area of 51.88% ± 14.25%. This was detectable via an increased bioimpedance signal with a significant increase 5 min in advance to fulminant clot formation inside the MO, which was monitored by the clinical gold standard (pressure difference across the MO (dp-MO)). This study demonstrates the feasibility of detecting clot growth early and effectively by measuring bioimpedance within an MO using integrated sensor fibers. Thus, bioimpedance may even outperform the clinical gold standard of dp-MO as a monitoring method by providing earlier clot detection.

Characteristics of Rock Avalanche Deposit in Wangjiapo, Ludian Based on UAV Aerial Image Recognition

Rock avalanche disasters in alpine and gorge regions are frequent and large in scale and cause severe damage. The movement of a rock avalanche is complex and has not been fully studied. The deposits of a rock avalanche can provide valuable insights into its movement process, which is crucial in understanding the rock fragmentation mechanism and predicting disaster-affected areas. Taking the Wangjiapo rock avalanche in Yunnan Province of China as an example, the size, shape and distribution characteristics of the deposit were analyzed based on field surveys, unmanned aerial vehicle (UAV) photography and image recognition technology. Initially, 3062 deposited rock blocks were manually measured in the field. Subsequently, the Particles/Pores and Cracks Analysis System (PCAS) was employed to identify 11,357 rock blocks with an area greater than 0.1 m2 from UAV orthophotos. By comparing the characteristics of the rock blocks obtained through image recognition and manual measurement, the statistical analysis of UAV aerial imagery combined with PACS proved feasible in studying the Wangjiapo rock avalanche. The results showed that the rock block movement was accompanied by fragmentation and sorting processes; furthermore, the roundness increased with the migration distance. Small blocks were more prevalent at the foot of the slope, while irregularly shaped, large blocks dominated in source areas. The movement of huge blocks was characterized by significant potential energy-driven features and inertia advantages, allowing them to travel farther than smaller blocks, and they tended to be concentrated in the central area of the deposit. Additionally, affected by the cementation degree of breccia and the topography, the blocks in the eastern and western deposit areas exhibited different fragmentation and deposition characteristics.

Post-mortem analysis of the deposit layers on the lower divertor after the 2023 high particle fluence campaign of WEST

We analysed deposits collected on the lower divertor of WEST after the first high fluence campaign performed in 2023. Deposits were collected on the high field side (thick deposition area) of 2 ITER-grade plasma facing units (PFUs), located on different toroidal positions. Using focused ion beam cross sectioning, the deposits were found to be very thick (12–55 µm). A significant difference was observed in the toroidal direction with thicker deposits for the PFU located at the maximal heat load in the inner side, showing a deposition pattern due to the toroidal magnetic field modulation. Deposits present a complex layer-by-layer structure with dense layers, some melted parts and porosities within the layers. The deposition is mainly composed of tungsten with oxygen, boron, carbon and traces of nitrogen whose composition vary along the radial direction. We identified W-rich deposits in the high plasma flux area near the inner strike point and deposits rich in O, B, C and N in the low plasma flux area further away from this strike point. W dense layers of about 5 up to 40 µm thick in the thick deposit area near the strike point were attributed to the high fluence campaign. Pure boron layers resulting from wall conditioning and processed by plasma wall interactions were also observed.

Genesis of the Longfengchang polymetallic sulfide deposit in the southwest Fujian depression, southeast China, with a comparative study of the “Makeng-Type” iron deposit

The Southwest Fujian Depression Belt is a prominent metallogenic zone for skarn-type iron polymetallic deposits in China, with the Longfengchang (LFC) sulfur polymetallic deposit representing a medium-scale, sulfide-dominated deposit in this region. This study conducted a detailed analysis of the LFC deposit, focusing on its mineralogy, mineral composition, and in-situ sulfur isotopes, alongside a comparative study with the “Makeng-type” deposit. The study aims to elucidate the genesis of the LFC deposit, its relationship with the “Makeng-type” deposit, and the factors underlying differences in dominant economic minerals and resource scale. The LFC deposit is hosted within the skarn above the fault contact zone between the Lindi Formation sandstone and the Chuanshan–Qixia Formation carbonate, with mineralization stages classified as skarn-magnetite, quartz-sulfide, and carbonate. LFC garnets are primarily composed of CaO, TFeO, and SiO2, with minor Al2O3 and trace amounts of MgO and MnO, classifying them as distal exoskarn andradite. The presence of Mn3+ substituting for Fe3+ in garnet suggests that the ore-forming fluid during the garnet skarn stage was likely oxidizing and weakly acidic. LFC pyrites exhibit Co/Ni ratios primarily ranging from 1 to 10, decreasing from Py1 to Py3. In-situ sulfur isotope δ34S values range from −1.48 to 3.51 ‰, centering around 0 ‰, and increase from Py1 to Py3, suggesting a magmatic-hydrothermal origin and a cooling metallogenic process. Thus, the LFC deposit is classified as a magmatic-hydrothermal skarn-type deposit, consistent with the genesis of “Makeng-type” deposits. The absence of the Jinshe Formation, and mantle-derived magma contribution, and less developed “Si-Ca” interface may explain the smaller scale and different mineralization type in the LFC deposit compared to the “Makeng-type” deposit. The key prospecting area for large iron-sulfur polymetallic deposits in the Southwest Fujian Depression Belt should feature a nappe structural window, well-preserved Jinshe Formation, developed “Si-Ca” interface, Yanshanian high-K calc-alkaline to shoshonitic intrusions, and coeval mantle-derived magma.

Distribution, enrichment characteristics and prospecting potential of lithium in Uzbekistan: Insights from 1:1 million geochemical mapping

With the world economy gradually shifting to alow‑carbon and greener model in recent years, there is a growing need for developing key metals like lithium in economic development. Economic growth has sped up the country's shift to a green economy along with Uzbekistan's reform and opening up, and the country's developing major mineral resources, such as lithium, have garnered a lot of attention. Owing to lithium resource protential of Uzbekistan is unclear, it is important to examine the possibility of lithium mineralization. The distribution and enrichment characteristics of lithium in the Uzbeksitan Tianshan are studied in this paper, based on geochemical mapping data at a 1:1000000 scale. It's concluded that stream sediments from the Tianshan region of Uzbekistan have higher concentration of lithium than the continental crust, and the South Tianshan has the highest lithium content. Lithium mineralization has been found in the lithium-geochemical anomaly areas in the eastern part of Uzbekistan South Tianshan through field investigation. Spodumene pegmatite, the first instance of pegmatitic type lithium mineralization in this region and even in the Tianshan orogenic belt of Central Asia. In conjunction with the geological background analysis, the metallogenic potential of lithium was assessed, resulting in the identification of four regions with lithium geochemical anomaly, and these sites will serve as target areas for Li deposits prospecting work in the future. This work has significant implications for the advancement of our understanding of the metallogenic theory of pegmatite-type Li deposits, as well as practical guiding significance for lithium ore prospecting in the Tianshan orogenic belt of Central Asia.

Amelioration of full-thickness cutaneous wound healing using stem cell exosome and zinc oxide nanoparticles in rats

BackgroundWound healing is a complex procedure that requires the coordination of several factors, so this study aimed to assess the zinc oxide nanoparticles’ regenerated effect and stem cell exosomes on full-thickness wounds in rats. MethodsSeventy-two Wistar male rats were subjected to a full-thickness skin defect (20 mm2) on the dorsal surface of each rat between two shoulder joints. The rats were randomized into four groups (18/group) according to wound treatments. The wounds were irrigated with normal saline (Control group), or the wound's edges were subcutaneously injected daily with 0.3 ml of exosome (Exo-group), or 1 ml of zinc oxide nanoparticles (ZnO2-NPs group), or 0.3 ml of exosome in combined with 1 ml of zinc oxide nanoparticles (Exo/ZnO2-NPs group). On the 7th, 14th, and 21st days post-wounding, the weight of the rats, the wound healing breaking strength, the wound size, and the contraction percent were evaluated. Six rats in each group were euthanized at each time point for histopathological, immunohistochemical examination of collagen, the levels of alpha-smooth muscle actin (α-SMA), and epidermal growth factor receptor (EGFR). additionally, the gene expression analysis of the relative renal nuclear factor erythroid 2-related factor2 (Nrf2 mRNA), Transforming growth factor beta-1 (TGFβ1), fibroblast growth factor-7 (FGF7), Transforming growth factor beta-1 (TGFβ1), Lysyl oxidase (LOX), and Vascular endothelial growth factor (VEGF) were applied. ResultsThe Exo-group exhibited a significant decrease in wound size and a significant increase in wound contraction compared with other groups. Histopathologically evaluation during the three intervals revealed that the Exo-group had the highest collagen deposition area with a significant reduction of the granulation tissue. Moreover, upregulated gene expression profiles of the growth factors genes at all time points post-wounding. DiscussionThe exosomes-treated group revealed superior wound healing and contraction, with minimal inflammatory signs, higher angiogenesis, and myofibroblasts, and associated with higher growth factor expression genes compared to the other groups. ConclusionsExosome-based therapy demonstrates potential as a treatment method to promote and accelerate wound healing by modulating angiogenesis, re-epithelialization, collagen deposition, and gene expression profiles.

Lead and Barium strata-bound deposits in eocene carbonate ramps of Iran: Implications for the influence of sedimentary environment characteristics on the distribution of Ore reserves

In the case of ore deposits that are formed in marine environments, including kuroko deposits, the effect of paleo-sedimentary environment parameters and microfacies changes is very important, but it is often neglected in economic geological research. These factors determine the dispersion and concentration of ore horizons in an ore deposit area, and recognition them leads us to the localization of high concentration ore horizons.In this regard, lead and barite ore deposit area in the southeastern of Tafresh city (the border of Markazi and Qom provinces, Iran) was investigated. This ore deposit is of the kuroko type and is of the early to middle Eocene epoch (Ypresian-Lutetian ages) and was formed in a relatively deep ancient carbonate ramp. Investigating the concentration of different minerals and ore minerals in the mentioned ore deposit area using by remote sensing techniques indicates that the distribution of minerals and ore minerals is non-uniform with a noteworthy correlation unto the carbonate ramp microfacies in the southeastern of Tafresh. The scrutiny of microfacies characteristics and paleo-sedimentary environment showed that the distance from hydrothermal smokers, the action of different seawaves, sedimentological changes, structural features and initial morphology of microfacies have a remarkable impressiveness in the dispersion of ore reserves and the formation of horizons with a high concentration of ore.

Effects of Shaofu Zhuyu decoction on intestinal flora and fibrosis in a mouse model of endometriosis

Shaofu Zhuyu decoction has been widely used to treat gynecological diseases; however, its mechanism of action in endometriosis remains unclear. We analyzed Shaofu Zhuyu decoction’s chemical composition using ultra-high performance liquid chromatography-mass spectrometry. In an endometriosis mouse model, ectopic lesions weight measurements and hematoxylin and eosin staining were used to assess the therapeutic efficacy of Shaofu Zhuyu decoction. Effects on intestinal microflora were analyzed using 16S ribosomal ribonucleic acid sequencing, and impacts on focal fibrosis were analyzed using Masson’s trichrome staining. Moreover, fibrosis- and metabolism-related proteins were assessed using immunohistochemistry and enzyme-linked immunosorbent assay. The study identified 157 chemical constituents within Shaofu Zhuyu decoction. Shaofu Zhuyu decoction treatment in mice with endometriosis resulted in a reduction in ectopic lesions weight (P<0.05) and delayed disease progression. Moreover, it improved the diversity and abundance of intestinal flora, and decreased the expression of Lachnospiraceae (P<0.05), Rikenellaceae (P<0.01), Ruminococcaceae (P<0.01), Lachnoclostridium (P<0.05), and unclassified_f__Ruminococcaceae (P<0.05). Kyoto Encyclopedia of Genes and Genomes analysis revealed enrichment in carbohydrate, amino acid, and lipid metabolism pathways. Masson’s trichrome staining revealed that compared to the untreated group, the Shaofu Zhuyu decoction group exhibited significantly reduced collagen deposition areas (P<0.001), lower TGF-β1 (P<0.001), COL1A1 (P<0.05), and α-SMA (P<0.01) expression in ectopic lesions, along with increased serum adiponectin (P<0.05), decreased serum leptin (P<0.05), TGF-β1 (P<0.001), and CTGF (P<0.05). Shaofu Zhuyu decoction regulates the intestinal flora of mice with endometriosis while also reducing fibrosis at the lesion site. These findings highlight novel mechanisms for its efficacy in alleviating endometriosis.

Non-consistent changes and drivers of water-sediment fluxes in the yarlung tsangpo river basin of the Tibetan plateau

Variations in water-sediment fluxes and their driving mechanisms are critical to riverine ecosystems and management. Yet, current estimates of the response of water and sediment flux remain insufficiently quantified, limited by the scarcity of long-term hydrological records in the alpine regions. Here, we leverage decadal observations in the Yarlung Tsangpo River basin, to investigate the dynamic shifts in water-sediment fluxes from 1955 to 2020 and elucidate their linkage to a warming and wetting climate, snowmelt, and environmental greening (including natural- and human-induced greening) in the different spatial and temporal scale. Major drivers of shifts in water-sediment flux are identified by using wavelet coherence and variance partitioning of redundancy analysis. The results highlight that observational data from four gauging stations (i.e., Lhaze, Nugesha, Yangcun, and Nuxia) uncover a substantial decrease in suspended sediment load (SSL) (Nuxia: 12.302 × 104 t/yr, P < 0.05) in the downstream with consistently increasing runoff and precipitation. Especially during the flood season (July to September), the dam/reservoir construction caused a median decrease in SSL. Dropping sediment offsets the slightly rising SSLs in the midstream and upstream (upper Yangcun: 14.8 × 104 t/yr, P > 0.05). Up to 80% of sediment was sourced from the middle stretch between Lhaze and Nugesha despite it supplied with lower regional runoff generation. Nevertheless, the downstream zone experienced the transition from a sediment source to a deposition area around 1998. We further found the negative and positive effects between water-sediment fluxes and revegetation, and demonstrated that employing NDVI to evaluate human-induced vegetation greening might overestimate the impact of ecological restoration programs on water-sediment fluxes. Attribution analysis indicates that precipitation was not the primary contributor to runoff and SSL changes in all stretches of the basin. In the upstream, temperature and associated snowmelt can be more important than precipitation. Compared to before 1998, precipitation is still the primary driver of change in downstream runoff change after 1998, whilst vegetation restoration, rather than precipitation, dominates the reduction in downstream SSL. These findings have far-reaching significance for watershed managers and decision-makers in terms of developing effective strategies for water resources and soil erosion control.

Modelo cinemático del control estructural 4D y metalogénesis del distrito auroargentífero Vetas-California (Santander, Colombia)

). The gold and silver deposits of the Vetas-California mining district are hosted in Paleozoic gneisses and Mesozoic granites of the Santander massif in the Eastern Cordillera of Colombia, far from the northern Andean volcanic arc. In the California area, there is ambiguity in defining the epithermal-type metallogenic model with high to intermediate sulfidation due to the presence of Late Triassic-Early Jurassic and Miocene magmatism. The best-known hydrothermal episodes comprise two early porphyritic-style phases: a) characterized by a propylitic alteration with molybdenite of the ~10.1 Ma-old La Mascota breccia, related to granodiorite porphyries and smaller-volume rhyodacitic dykes; and b) attributed to a magmatic-hydrothermal system due to phyllic alteration associated with quartz-pyrite veins with hydrothermal sericite dated at ~3.4 Ma. These two hydrothermal episodes were followed by four epithermal phases related to the development of multiphase hydrothermal breccias and quartz-alunite alteration, defined by bornite, covellite, and chalcopyrite, alongside wolframite, enargite, and sphalerite, with gold and silver mineralization between ~2.6 and ~ 1.6 Ma. To understand the relationship of the emplacement of the porphyries and the subsequent auro-argentiferous enrichments to the deformation front observed in the Pamplona buttress, to the east of the Santander Massif, a 4D structural model of the mineralization is formulated here. This model is based on the spatial analysis of the stresses responsible for the La Baja-Angostura dextral fault in terms of the regional kinematics of the Bucaramanga sinistral fault. It is considered that the SW sector of the deposit area corresponds to a well-defined, tabular, sub-vertical body of the La Mascota breccia. On the other hand, the NE sector in the La Baja-Angostura fault is expressed as a topographically elevated right horsetail splay, which controls the more disseminated distribution of the mineralization by means of veinlet swarms arranged in an ~E-W direction. The disseminated mineralization of Vetas-California was probably favored by late thermal expansion-contraction events in the gneissic sockets, which allowed the accumulation and precipitation of boiling solutions rich in volatiles and elements of economic interest.

Investigating sediment dynamics on a continental shelf mud patch under the influence of a macrotidal estuary: A numerical modeling analysis

Shelf mud patches represent major sinks for fine-grained particles on continental shelves, as well as for carbon and contaminants of continental origin. The West Gironde Mud Patch (WGMP) is an interesting example of such offshore marine systems as it is an active mud deposition area located offshore the Gironde estuarine mouth (France) at depths between 30 and 70 m. It is known to be the trap of fine particles coming from the estuary, but the contribution of this material to the total mass of the depocenter is poorly quantified. In addition, despite the economic and ecological issues at stake, the response of such subtidal sedimentary structure to the combination of tidal currents, waves, and river supply remain poorly understood. Thus, using a realistic 3-D hydrodynamic and mixed (mud/sand) sediment transport model, this study aims at investigating the sediment dynamics of the WGMP under different hydrometeorological conditions. The analysis of the residual fluxes at the estuarine mouth exhibited large discrepancies between the different sediment classes as well as for contrasted hydro-and meteorological conditions induced by different dominant transport mechanisms. During winter, the reinforced density gradients drive strong up-estuary baroclinic circulation at the bottom that dominates the sediment dynamics over the barotropic export of mud particles. The model also reproduced the signature of a subtidal mud accumulation area over the continental shelf around 30–40 m water depth, on the proximal side of the observed WGMP. On average over two years, 26% of the mud mass accumulating on the simulated subtidal mudflat comes from the estuary. The trapping efficiency of this mud patch is negatively correlated with the significant wave height. Moreover, due to the estuarine turbid plume being more concentrated and developed at the surface during high river discharge, the trapping efficiency of the mud body is enhanced compared to lower discharge. This study highlights the sensitivity of mud and sand fluxes to vertical and horizontal residual circulation, and points out the uncertainties associated with the simulation of short-term (i.e., years) fine particle deposits compared to long-term (i.e., centuries) sediment accumulation trends. In addition, these results show the primordial effects of both wave action and riverine sediment supply on the dynamics of such subtidal muddy structures, which raises concern about their fate facing climate change and human activities in the future.

Using SAR imagery to extract flash flood sediment deposition area in the northern Loess Plateau

The lack of hydrology data brings challenges to the accurate simulation of the inundation range of flash floods using hydrodynamic models. In addition, the water bodies of flash floods often disappear quickly, which makes it difficult for remote sensing satellites to extract flash flood inundated areas without standing water. There is currently no research using flood sediment deposition areas to characterize flash floods in areas without water accumulation. To address this research gap, we developed a method based on Google Earth Engine (GEE) that uses Sentinel-1 SAR imagery to automatically extract flash flood sediment deposition areas. This method, termed Power Operation of Different Polarization Combination (PODPC), differs from other feature extraction methods in that it utilizes not only the original Vertical-Vertical (VV) and Vertical-Horizontal (VH) polarizations and their simple combinations but also employs power operations and threshold techniques to extrac t sediment deposition areas. We explored the advanced features of PODPC in terms of extraction accuracy, threshold segmentation effect, and sediment deposition area distribution. The results demonstrate that the histograms generated by PODPC exhibit clearer bimodal characteristics, facilitating better threshold selection. VV3, (VV + VH)6, and (VV × VH)3 produced fewer false deposition areas, achieving an overall accuracy of 92 % ∼ 93 %. Compared to commonly used methods such as VV, VH, and VV + VH, PODPC increased the overall accuracy by an average of 23 %. (VV-VH)n and (VV/VH)n are are considered unsuitable for the extraction of sediment deposition areas. The extracted sediment deposition area can serve as indicator of flash flood severity and as validation and input data for flash flood models, enhancing the scientific assessment of flash flood disasters.

Incorporating Effects of Slope Units and Sliding Areas into Seismically Induced Landslide Risk Modeling in Tectonically Active Mountainous Areas

Traditional Newmark models estimate earthquake-induced landslide hazards by calculating permanent displacements exceeding the critical acceleration, which is determined from static factors of safety and hillslope geometries. However, these studies typically predict the potential landslide mass only for the source area, rather than the entire landslide zone, which includes both the source and sliding/depositional areas. In this study, we present a modified Newmark Runout model that incorporates sliding and depositional areas to improve the estimation of landslide chain risks. This model defines the landslide runout as the direction from the source area to the nearest river channel within the same slope unit, simulating natural landslide behavior under gravitational effects, which enables the prediction of the entire landslide zone. We applied the model to a subset of the Minjiang Catchment affected by the 1933 MW 7.3 Diexi Earthquake in China to assess long-term landslide chain risks. The results indicate that the predicted total landslide zone closely matches that of the Xinmo Landslide that occurred on 24 June 2017, despite some uncertainties in the sliding direction caused by the old landslide along the sliding path. Distance-weighted kernel density analysis was used to reduce the prediction uncertainties. The hazard levels of the buildings and roads were determined by the distance to the nearest entire landslide zone, thereby assessing the landslide risk. The landslide dam risks were estimated using the kernel density module for channels blocked by the predicted landslides, modeling intersections of the total landslide zone and the channels. High-risk landslide dam zones spatially correspond to the locations of the knickpoints primarily induced by landslide dams, validating the model’s accuracy. These analyses demonstrate the effectiveness of the presented model for Newmark-based landslide risk estimations, with implications for geohazard chain risk assessments, risk mitigation, and land use planning and management.

Prototypical basin reconstruction and evolutionary models for the Precambrian of the Qinshui Basin, North China craton

The thick Precambrian strata in the Qinshui Basin (QB) have high potential for hydrocarbon exploration. Tectonic evolution restoration and prototype basin reconstruction are key to hydrocarbon exploration and evaluation for Precambrian strata. We studied the 2D/3D seismic data and Precambrian field outcrops of the QB to elucidate its geological attributes, major regional unconformities, tectonostratigraphic framework, tectonic evolution and prototype basin. The Precambrian strata of the QB are the sedimentary products of the continuous transgression from south to north and are more appropriately attributed to the Xiong'er Aulacogen in the Changchengian and Jixian periods. We identified six regional unconformities: the Archean or Palaeoproterozoic/Xiong'er Group, the Xiong'er Group/Chy, Chc/Chl, Chl/Jxl, the Jxl/Cambrian System, and the Ordovician/Carboniferous. Seven tectonostratigraphic units can be delineated: the Archean–Palaeoproterozoic, Xiong'er Group, Yunmengshan–Cuizhuang, Luoyukou, Jixian, Cambrian–Ordovician, and Carboniferous–Triassic tectonostratigraphic units. The tectonic evolution was divided into seven stages: the formation and evolution of the basement (∼1800 Ma), the synrift stage in the Xiong'er period (1800–1720 Ma), the postrift stage in the Yunmengshan–Luoyukou period (1720–1600 Ma), the passive continental margin basin stage in the Jixian period (1600–1400 Ma), the marine craton stage during the Cambrian–Ordovician (542–440 Ma), the marine–continental transitional–continental craton stage during the Carboniferous–Triassic (316–200 Ma), and the intense deformation stage (200–0 Ma). Three stages of prototype basin models of the Precambrian in the QB have been reconstructed: (1) In the synrift basin model, numerous normal faults have developed, and the section shows a symmetrical composite graben. The topography in the south is low, that in the north is high, and the northeast and northwest areas are palaeo-uplifted. A set of volcanic rocks with coarse-grained clasts was deposited. (2) In the postrift basin model, the fault activity weakened, and the depositional range became larger than that of the synrift stage, and a set of marine clastic–carbonate rocks was deposited showing a gradual coarsening–upwards trend. (3) In the passive continental margin basin model, the fault became almost inactive, the topography was low in the southeast and high in the northwest, and the depositional area was more widespread, resulting in a set of marine carbonates. These results contribute to a better understanding of the break-up process of the Columbia supercontinent and the Precambrian evolution of the North China Craton (NCC) and can be used to predict the distributions of source rocks and hydrocarbons.

Thermal and statistical analysis of the high-Z tungsten-based UFOs observed during the first deuterium high fluence campaign of the WEST tokamak

This paper summarizes the observations on the Unidentified Flying Object (UFO) observed during the first high fluence campaign performed in WEST. The campaign was characterized by high erosion and deposition rates, generating dusts and deposits prone to flaking during plasma operation. A total of 686 UFOs have been detected for 384 discharges executed, in which 133 UFOs lead to a disruption. These UFOs appear mostly during the low hybrid heating ramp-up early in the discharges. The mechanisms leading to a disruption is described as well as the delay available to react after the UFO entering in the plasma. The UFOs originate mostly from the high field side corresponding to the thick deposit area. These UFOs can be debris from a preceding disruption (≈27 %) or come from progressive loss of adherence of the thick deposits (≈55 %) under plasma cycling or more likely by disruption on this area. Finally, the thermal resistance of the poorly attached deposits has been calculated in the range from 2.10−4 °C m2/W to 1.10−3 °C m2/W coherent with previous observations in the high field side of the JET divertor.

Contribution of collagen-binding protein Cnm of Streptococcus mutans to induced IgA nephropathy-like nephritis in rats

IgA nephropathy (IgAN), the most common primary glomerulonephritis, is considered an intractable disease with unknown pathogenic factors. In our previous study, Streptococcus mutans, the major causative bacteria of dental caries, which expresses Cnm, was related to the induction of IgAN-like nephritis. In the present study, the Cnm-positive S. mutans parental strain, a Cnm-defective isogenic mutant strain, its complementation strain, and recombinant Cnm (rCnm) protein were administered intravenously to Sprague Dawley rats, and the condition of their kidneys was evaluated focusing on the pathogenicity of Cnm. Rats treated with parental and complement bacterial strains and rCnm protein developed IgAN-like nephritis with mesangial proliferation and IgA and C3 mesangial deposition. Scanning immunoelectron microscopy revealed that rCnm was present in the electron-dense deposition area of the mesangial region in the rCnm protein group. These results demonstrated that the Cnm protein itself is an important factor in the induction of IgAN in rats.