Erosion Formation Research Articles

Cross-shore hydrodynamics and morphodynamics modeling of an erosive event in the inner surf zone

The phase-averaged and depth-integrated coastal morphodynamic model, XBeach-Surfbeat, was investigated for its capability of predicting the cross-shore hydrodynamics and morphodynamics in the inner surf zone by simulating the storm-induced berm erosion, sediment transport, and subsequent sand bar formation. By utilizing a comprehensive hydrodynamic and morphodynamic dataset measured in a large wave flume and high-fidelity 3D large-eddy simulation (LES) data, a rigorous model validation was conducted to assess its capability in predicting inner-surf zone hydrodynamics and to explore how the improved hydrodynamic performance impacts the predicted morphodynamics. Using the default model parameters of the model, the undertow was overestimated with the peak magnitude being 30%–35% larger in the inner surf zone. Combining Monte Carlo simulation, the optimum hydrodynamic calibration for the simulated undertow was achieved when the roller energy dissipation parameter (β) was maintained below 0.1, and the threshold water depth (hmin) exceeded 0.25 m. The calibrated undertow improved the morphodynamic predictions by reducing the excessive berm erosion (Event I) and sand bar growth in the inner surf zone (Event II). Further improved morphodynamic predictions were achieved by calibrating sediment transport parameters, including the onshore sediment transport coefficient (γua) and the bore interval coefficient (Tbfac) associated with turbulence-bed interaction. A consistent set of optimized model coefficients for the model is shown to be effective in simulating the entire erosive event (combined Events I and II). This study reveals that further improvement of the model's capability may require incorporating new parameterizations and physics, such as wave-breaking-induced turbulence and wave nonlinearity associated with sediment transport in the inner surf and swash zones.

Soil Loss Estimation and Community Awareness Assessment on Integrated Watershed Management: The Case of Lake Hashenge Watershed, Tigray, Ethiopia

Ethiopia is recognized as one of the most severely affected regions by soil erosion globally, posing significant threats to its national economy. This study investigates soil loss estimation and community awareness within the framework of integrated watershed management in the Lake Hashenge watershed, Tigray, Ethiopia. The mean annual rainfall and total drainage area of Lake Hashenge watershed is 988.7 mm and 129km2 respectively. Utilizing the Revised Universal Soil Loss Equation (RUSLE) model, we quantified soil erosion rates and identified critical areas prone to severe soil loss. Our findings indicate significant soil degradation, exacerbated by both natural and anthropogenic factors. The estimated soil loss yield entering Lake Hashenge in the form of sheet and rill erosion was 61.94 tons/ha/year. According to the universal soil loss factsheet, the soil loss estimated in the watershed was categorized as severe, indicating that the lake is in danger. Concurrently, we assessed community awareness and participation in soil conservation practices through surveys and interviews with a multidisciplinary team of researchers. The results reveal a moderate level of awareness and engagement, highlighting the need for enhanced educational and participatory approaches to foster sustainable watershed management. This research underscores the importance of integrating scientific soil loss assessments with community-based integrated watershed management strategies to mitigate soil erosion, protect the lake from sedimentation, and promote environmental sustainability in the region.

Characteristics and development of steepland gullies in the dry valleys of Southwest China.

In semi-arid and arid areas, gully erosion is one of the most destructive forms of erosion and causes serious land degradation and resource destruction. Steepland gullies are widely distributed in the dry valleys of southwest China, and their formation is one of the main causes of soil erosion and the destruction of sloping farmland in the region. Previous research on the development of steepland gullies is limited, and further study is needed. In this study, 11 steepland gullies at various stages of development located in Guobu Village, Xide County, Liangshan, Sichuan Province, were selected for investigation using a digital elevation model (DEM) derived from unmanned aerial vehicle data as the primary data source. These data had a spatial resolution of 0.1 m. Fundamental parameters such as the gully length, width, depth, area, and volume were extracted from the remote sensing data. Other characteristic parameters, including the coefficient of main and tributary gullies, vertical gradient, gully elongation, and gully openness, were also investigated. The results indicate a significant linear positive correlation between the gully's degree of openness and elongation as the gully's length, width, and depth increase. Furthermore, the vertical gradient and coefficient of main and tributary gullies exhibit power-law relationships with these gully dimensions. The development of steepland gullies was divided into infancy, youth, maturity, and old age based on the use of the gully length as an ergodic indicator in space-for-time substitution. The morphological characteristics of these different stages were quantitatively analyzed, and a proposed mechanism for how the evolution of the gullies proceeds was developed. An empirical model of volume-length erosion was established to investigate the development process of steepland gullies in the dry valleys. It has been observed that the development law of steepland gullies is essentially consistent with the very active stage of typical gully formation, suggesting that steepland gully may represent the initial stage of gully development. The results show that these steepland gullies have their origin in high-intensity rainfall events that are accompanied by the formation of steps and drop water. The effects of gravity erosion and hydraulic erosion then cause the gullies to expand rapidly, forming gullies with a large head and a small tail before they gradually stabilize. The results of this study will help with the understanding of the formation and evolution of steepland gullies and will be of practical significance for the prevention of gully erosion and the protection of sloping farmland in the dry valley region of southwest China.

Sandy soil spots in northwestern Paraná: approaches for identification and quantification

The predominance of sandy soils in the Northwest region of the state of Paraná, associated with the removal of natural vegetation, favored the development of patches of white sand on the surface without any aggregation. These spots are associated with the different types of land use existing in the region and the process of lateral soil transformation. As they constitute material without aggregation, they can be easily transported by wind and water and deposited in water bodies, causing severe environmental impacts. Thus, using thermal infrared satellite images, the objective of the present study was to map, determine the formation process of the spots and estimate the predominant particle size fractions. The model used and validated with field and laboratory information, allowed the identification of surfaces with patches of white sand present in the study region and estimating their percentage in different classes. After filtering the samples with vegetation cover during the product calculation period, an R² of 0.78 was obtained. The removal of natural vegetation has contributed to the formation and expansion of sandy patches and erosion in the northwest region of Paraná.

Evaluating rainfall erosivity index from CHIRPS and INMET data in southeast region of Goiás (Brazil)

Abstract. Soil erosion is a form of land degradation commonly observed in different regions of the world, especially in tropical regions. In Brazil, soil erosion caused by rainwater (pluvial erosion) is the most common and worrying form of erosion, causing various environmental, economic and social damage. The main aim of this work was to evaluate the Erosivity Index (EI) relationships based on CHIRPS and INMET data in the municipality of Catalão-GO, that is located in one of the world's largest agricultural frontiers, the Brazilian Cerrado. The results found indicated that the CHIRPS data it is an alternative for calculating EI in the context of municipality of Catalão, southeast region of Goiás state, from a previous stage for statistical validation.

Analysis and mitigation of erosion wear of transfer ducts in a falling particle CSP system

Solid particles are effective heat capture and transfer media for next-generation (Gen3) concentrating solar power (CSP) plants that offer high-temperature operability, lower levelized cost, and higher efficiency. However, the relative motion of the solid particles with respect to the CSP system components causes significant wear of the wall materials in the form of erosion and abrasion. The transfer duct is one of the prevalent components in the falling particle CSP system that experiences erosion wear due to the impact of particles on its surface, which depends on several factors, such as duct design, material, and particle flow rate, among others. In this work, erosion wear in the transfer duct and its mitigation were studied computationally through different duct designs and particle flow parameters, including transfer duct length, diameter, slanted angle of the duct, and entrance velocity. Computational simulations based on particle tracking and discrete element modeling were used to understand erosion behavior systematically and, in turn, identify areas most prone to erosive wear. It was found that the use of erosion-resistant coatings in selected locations determined from the simulations was sufficient to mitigate overall erosion wear in the component. This study provides fundamental insight into the erosion wear of a key component of the falling particle CSP system for the first time and the design approaches to mitigate wear.

The complex pathophysiology and clinical management of epidermolysis bullosa: a comprehensive review

Epidermolysis bullosa (EB) represents a group of rare, genetically heterogeneous disorders characterized by the formation of blisters and erosions of the skin and mucous membranes in response to minor mechanical trauma. EB is classified into four major types-EB simplex, junctional EB, dystrophic EB, and Kindler syndrome, each associated with mutations in specific genes that encode structural proteins essential for skin integrity. The clinical spectrum of EB ranges from mild forms, presenting with localized skin involvement, to severe variants that lead to widespread blistering, mutilating scarring, and significant morbidity. The pathophysiology of EB is complex, involving disruptions in the adhesion between the dermis and epidermis, leading to compromised structural stability of the skin. Current therapeutic strategies focus on symptom management, including wound care, infection prevention, and pain control, as no definitive cure exists. Advances in gene therapy, stem cell therapy, and protein replacement therapy hold promise for future treatment paradigms. This review aims to elucidate the molecular underpinnings, clinical manifestations, and emerging therapeutic approaches for EB, providing a comprehensive overview for clinicians and researchers engaged in the management and study of this challenging condition.

The Ways of Forming and the Erosion/Decay/Aging of Bioapatites in the Context of the Reversibility of Apatites.

This study primarily focused on the acid erosion of enamel and dentin. A detailed examination of the X-ray diffraction data proves that the products of the acid-caused decay of enamel belong to the family of isomorphic bioapatites, especially calcium-deficient hydroxyapatites. They are on a trajectory towards less and less crystallized substances. The increase in Bragg's parameter d and the decrease in the energy necessary for the changes were coupled with variability in the pH. This was valid for the corrosive action of acid solutions with a pH greater than 3.5. When the processes of natural tooth aging were studied by X-ray diffraction, a clear similarity to the processes of the erosion of teeth was revealed. Scarce data on osteoporotic bones seemed to confirm the conclusions derived for teeth. The data concerning the bioapatite decays were confronted with the cycles of apatite synthesis/decay. The chemical studies, mainly concerning the Ca/P ratio in relation to the pH range of durability of popular compounds engaged in the synthesis/decay of apatites, suggested that the process of the formation of erosion under the influence of acids was much inverted in relation to the process of the formation of apatites, starting from brushite up to apatite, in an alkaline environment. Our simulations showed the shift between the family of bioapatites versus the family of apatites concerning the pH of the reaction environment. The detailed model stoichiometric equations associated with the particular stages of relevant processes were derived. The synthesis processes were alkalization reactions coupled with dehydration. The erosion processes were acid hydrolysis reactions. Formally, the alkalization of the environment during apatite synthesis is presented by introducing Ca(OH)2 to stoichiometric equations.

Time-dependent reliability analysis of flood defenses under cumulative internal erosion

Internal erosion is a significant cause of failure in dams, levees and other hydraulic structures. This article studies the time-dependent reliability of such structures under Backward Erosion Piping (BEP), a form of internal erosion in the foundation. First, a physics-based time-dependent piping failure model is presented. Second, a time-variant reliability analysis method is presented which allows to quantify how the reliability evolves over the years due to cumulative pipe growth over multiple flood events. Finally, these models are used to study the importance of time-dependence for reliability estimates of flood defenses in The Netherlands. The findings show that, particularly in coastal areas, incorporating time-dependence significantly reduces the computed failure probability. Reductions vary widely, ranging from a factor of 5 to more than 10 6 , depending on flood duration and levee properties. Therefore, reliability estimates for levees can be improved by incorporating time-dependent pipe development in the BEP failure model, and thereby contribute to avoiding unnecessary reinforcements.

Analgesic activity of a new cannabinoid CB1 receptor modulator

Aim. To study the analgesic activity, the effect on motor functions, and the potential ulcerogenic effect of a new 2H-chromene derivative, a cannabinoid CB1 receptor modulator (code name – CHR).Materials and methods. The analgesic activity of the CHR compound was studied when injected intragastrically at an effective dose of 5 mg / kg in mouse models of acute chemogenic pain (formalin test), acute visceral pain (the acetic acid-induced writhing test), and thermal nociception (hot plate test and tail-flick test). It was compared to the effect of tramadol and morphine or diclofenac sodium at doses of 20, 4 or 10 mg / kg, respectively. The effect of a single intragastric injection of the CHR compound at a dose of 5 mg / kg on motor activity was evaluated in the open field test. The potential ulcerogenic effect of the CHR compound at a dose of 5 mg / kg with repeated intragastric administration was compared with the effect of diclofenac sodium at a dose of 10 mg / kg.Results. With subplantar administration of formalin to mice, the 2H-chromene derivative reduced the number of pain reactions by 43–63% (p < 0.05). With intraperitoneal administration of acetic acid to mice, it reduced the number of writhing responses by 50% and had the same analgesic effect as diclofenac sodium and tramadol. In the hot plate test, the CHR compound increased the latency time to painful stimuli by 34% (p < 0.05). In the tailflick test, it increased the latency time to painful thermal sensations by 32% (p < 0.05). The CHR compound at an effective dose of 5 mg / kg did not change the motor activity of mice in the open field test and did not cause the formation of erosions and ulcers in the gastric mucosa when administered repeatedly to rats.Conclusion. The 2H-chromene derivative CHR at an effective dose of 5 mg / kg has a pronounced analgesic effect in mouse models of chemogenic, visceral, and thermal pain, which is as strong as that of tramadol, morphine, and diclofenac sodium used at effective doses. The CHR compound at an effective dose does not inhibit motor functions and does not have an ulcerogenic effect.

Microstructure and dry sliding wear evaluation of functionally graded coating deposited via atmospheric plasma spray

Surfaces are commonly enhanced with wear-resistant coatings to improve their resistance to abrasion, erosion, and other forms of wear. These coatings play a crucial role in extending the lifespan and improving the performance of materials and components exposed to challenging conditions. The objective of the current study is to deposit thermally sprayed 3-layer TiC–12Co–10ZrO2/NiCoCrAlMo functionally graded coatings on SS410 substrates using atmospheric plasma spray. The results revealed that by employing appropriate ceramic proportions, the microhardness of graded coatings increased to 990.4 HV, which is approximately 3.21 times higher than that of the substrate. Furthermore, the tribological properties of graded coating exhibited superior resistance compared to the substrate, where process settings were varied. Specifically, graded coating samples subjected to the applied load, sliding distance, and sliding velocity showed improved wear resistance of 78.51%, 68.42%, and 76.66% respectively in extreme conditions compared with uncoated samples. The characterization of the worn surface revealed a sequential occurrence of wear mechanisms: abrasive, adhesive, and delamination. The formation of TiO2 and Cr2O3 tribo-oxide film protects the surface against the wear mechanism and is applicable in extreme wear environments.

Salt weathering resilience in masonry: An accelerated laboratory study involving wind-induced variations

Salt weathering resistance is a critical parameter governing the durability of coastal masonry units and mortars. Accelerated weathering cycles are employed at the laboratory to investigate the responses of substrates and mortars upon exposure to salt, moisture, temperature fluctuations and humidity. In this paper, the individual and synergistic performances of bricks and mortar formulations when exposed to accelerated salt weathering cycles are investigated, incorporating the influence of wind on their resilience. The study examines the behaviour of brick-mortar sandwich specimens and separate specimens of bricks and mortar mixtures comprising cement, dry hydrated lime, fly ash, and limestone. These specimens are exposed to repeated weathering cycles in a 5 % sodium sulphate solution. Along with the mass variations during each weathering cycle, physicomechanical, microstructural, mineralogical and morphological characterization of the specimens are used to compare their salt weathering resistance. The results highlight that the responses of individual masonry components might not collectively translate to the overall performance of the combined system due to hygric resistance, which is minimal when the components have comparable pore size distribution. Higher microporosity (pores of diameter between 0.1 μm and 10 μm) and mechanical strength enough to resist the crystallization stresses together provide better resistance to salt weathering to the individual mortars. However, pore structure compatibility and pore fraction similarity between the components govern the behaviour of the combined system and, therefore, reflect the better performance of sandwich specimens with brick and lime mortars. The study demonstrated that wind accelerates material degradation during salt weathering through progressive erosion, accelerated evaporation and subsequent formation of isolated thenardite.

Strategies for Differential Diagnosis and Management of Ichthyosis in Newborns

Congenital ichthyosis represents agroup of heterogeneous inherited skin diseases characterized by generalized keratinization disorder in the form of hyperkeratosis, caused by abnormalities in epidermal differentiation. The neonatal period is crucial for patients with ichthyosis due to the risk of developing complications, comorbidities, and fatal outcomes. Most complications arise from impaired skin barrier function. This article discusses the manifestations of ichthyosis in newborns, describes risks and complications, and suggests strategies for monitoring and treating patients. Purpose of the study: to present contemporary data on differential diagnosis and treatment strategies for newborn patients with congenital ichthyosis. Materials and Methods: review of Russian and international sources dedicated to the etiology, diagnosis, and treatment of ichthyosis was conducted. Results: Differential diagnosis of ichthyosis in the neonatal period is acrucial task, hence the most life-threatening subtypes are considered. The most severe progression with ahigh risk of fatal outcomes is characteristic of Harlequin ichthyosis. Collodion baby presents with less pronounced symptoms, is not afinal diagnosis, and may later develop clinical manifestations typical of ichthyosiform erythroderma, lamellar ichthyosis, or self-resolving congenital ichthyosis. Netherton syndrome is characterized by acombination of congenital ichthyosis with structural abnormalities of the hair shaft and apropensity for atopy. Epidermolytic ichthyosis, accompanied by the formation of blisters and erosions on the skin, requires differential diagnosis not only with other forms of ichthyosis but also with bullous epidermolysis, staphylococcal scalded skin syndrome, and toxic epidermal necrolysis. Every newborn with described manifestations requires support from amultidisciplinary team of specialists and timely therapeutic and diagnostic measures aimed at preventing the development of complications and deterioration of the patient’s condition. Conclusion: An analysis of global literature data and the practical experience of the authors indicate the complexities of differential diagnosis of ichthyosis forms in the neonatal period. To improve skin condition, prevent infectious complications, and correct electrolyte and respiratory disturbances, symptomatic treatment should begin before adefinitive diagnosis is established.

Large Eddy Simulation of Cross‐Shore Hydrodynamics Under Random Waves in the Inner Surf and Swash Zones

AbstractA 3D large eddy simulation coupled with a free surface tracking scheme was used to simulate cross‐shore hydrodynamics as observed in a large wave flume experiment. The primary objective was to enhance the understanding of wave‐backwash interactions and the implications for observed morphodynamics. Two simulation cases were carried out to elucidate key processes of wave‐backwash interactions across two distinct stages: berm erosion and sandbar formation, during the early portion of a modeled storm. The major difference between the two cases was the bathymetry: one featuring a berm without a sandbar (Case I), and the other, featuring a sandbar without a berm (Case II) at similar water depth. Good agreement (overall Willmott's index of agreement greater than 0.8) between simulations and measured data in free surface elevation, wave spectrum, and flow velocities validated the model skill. The findings indicated that the bottom shear stress, represented by the Shields parameter, was significant in both cases, potentially contributing substantial sediment transport. Notably, the occurrence of intense wave‐backwash interactions were more frequent in the absence of a sandbar. These intense wave‐backwash interactions resulted in a pronounced horizontal pressure gradient, quantified by high Sleath parameters, exceeding the criteria for momentary bed failure. Additionally, a more vigorous turbulence‐bed interaction, characterized by near‐bed turbulent kinetic energy, was observed in the case lacking a sandbar, potentially augmenting sediment suspension. These insights are pivotal in understanding the mechanisms underlying berm erosion and how sandbar formation serves to protect further beach erosion.

Predicting gully formation: An approach for assessing susceptibility and future risk

AbstractGully erosion is a significant natural hazard and a form of soil erosion. This research aims to predict gully formation in the Kalshour basin, Sabzevar, Iran. Employing the Information Gain Ratio (IGR) index, we identified 13 key factors out of 22 for modeling, with elevation emerging as the most influential factor in gully formation. The study evaluated the performance of individual machine learning algorithms and ensemble algorithms, including the Functional Tree (FT) as the main classifier, Bagging (Bagg), AdaBoost (Ada), Rotation Forest (RoF), and Random Subspace (RSS). Using a data set of 400 gully and non‐gully points obtained through field investigations (70% for training and 30% for testing), the RoF model achieved an area under the curev (AUC) value of 0.99, indicating its high predictive ability for gully‐susceptible areas. Other algorithms also performed well (Ada: 0.90, FT: 0.92, RSS: 0.94, Bagg: 0.95). However, the RoF algorithm with the functional tree as the main classifier (RoF_FT) demonstrated the highest ability in gully classification and susceptibility mapping, enhancing the functional tree's performance. In addition to AUC, the RoF_FT model achieved an F1 score of 0.89 and an MCC of 0.78 on the validation set, indicating a high balance between precision and recall, and a strong correlation between predicted and actual classes, respectively. Similarly, other models showed robust performance with high F1 scores and MCC values, but the RoF_FT model consistently outperformed them, underscoring its robustness and reliability. The resulting gully erosion‐susceptibility map can be valuable for decision‐makers and local managers in soil conservation and minimizing damages. Implementing proactive measures based on these findings can contribute to sustainable land management practices in the Kalshour basin.Recommendations Gully erosion threat: Gully erosion poses a significant threat to soil, with far‐reaching environmental consequences. Predictive modeling: This research focuses on predicting gully formation in the Kalshour basin, Sabzevar, Iran, using advanced machine learning algorithms. Key findings for decision‐makers: The study evaluates the performance of various machine learning algorithms and ensemble algorithms, with the Functional Tree serving as the main classifier. This not only enhances our ability to predict gully formation but also provides a valuable tool for decision‐makers and local managers in soil conservation. Impact on sustainable land management: By offering a gully erosion‐susceptibility map, the research empowers decision‐makers to implement proactive measures, minimizing damage and contributing to sustainable land management practices. Interdisciplinary approach: The study's combination of geospatial analysis, machine learning, and soil conservation aligns with the journal's mission to advance understanding in environmental modeling.

Islands in the stream: Wood‐induced deposition and erosion in the river corridor

AbstractLarge wood causes and responds to deposition and erosion within a river corridor. We focus on the anastomosing, gravel‐bed Swan River and two meandering, gravel‐bed tributaries in northwestern Montana, USA to explore the temporal dimensions of deposition and erosion associated with channel avulsions and island formation and to introduce the concept of wood levees. Channel avulsion represents isolation of part of the existing floodplain and formation of an anastomosing channel planform, with wood‐induced deposition at the point of channel bifurcation. Islands form at a wood jam that migrates upstream with time as sediment accumulates in the lee of the jam. The island creates only a local interruption of the single‐channel planform. We use tree‐ring and 14C dating to constrain wood‐induced island ages. We interpret the three wood‐induced forms of deposition and erosion that we describe here as reflecting a temporal continuum. Wood levees have primarily non‐woody vegetation and may be transient relative to the other features. Tributary islands appear to persist from a decade to over a century. Tree ages of 100–200 years at the floodplain avulsion site and the characteristics of the secondary channels suggest that these wood‐induced avulsion features can persist for more than a century. Understanding the temporal dynamics of wood‐induced features and spatial variation in erosion and deposition provides insight into the dynamics and spatial heterogeneity of natural river corridors, with implications for river restoration.

Microstructuring of fused silica by laser-induced microplasma using a pyrographite target for phase optical elements fabrication

In this paper, we purpose to use laser-induced microplasma occurred from a pyrographite target by laser ablation for microstruturing of fused silica plate to fabricate phase optical elements. Laser parameters for erosive plasma torch formation and subsequent etching of fused silica were determined based on preliminary experimental studies and estimated energy calculations. The influence of the overlap coefficients in the focal spot on the reproducibility of etching depths results and the deviation accuracy of etching depths with the found laser parameters was experimentally studied. The best results in terms of accuracy (no more than 0.1 μm) in deviations of etching depths are achieved with the overlap coefficient of 0.5. Moreover, the paper presents estimated calculations of the speed and efficiency of ablation, as well as the coefficient of energy conversion from laser radiation to the ablation energy of fused silica, which was ∼ 0.25. Based on achieved results an attempt was made to fabricate the 6-sector SPP for the wavelength of 355 nm.

Effect of stress conditions on concentrated leak erosion resistant of fine-grained soils with different characteristics

Internal erosion is one of the most important factors that cause earth structures that retain water, such as embankment dams, to collapse. Concentrated leak erosion, one of the forms of internal erosion, occurs in cracked fine-grained soils and pressurized flow conditions. To evaluate the concentrated leak erosion risk of cracks/voids, it is necessary to ascertain the erosion resistance of these materials. The erosion rate and critical shear stresses determine internal erosion resistance in concentrated leak erosion. This study determined soil’s concentrated leak erosion resistance using test equipment that allowed the flow to pass through a hole with stress-free (no loading), anisotropic-compression stress, anisotropic-expansion stress, and isotropic stress conditions. The stresses that developed in the samples’ hole wall where erosion occurred were determined with numerical modeling as pre-experimental stress conditions. The experiments were performed under a single hydraulic head on four selected cohesive soils with different erosion sensitivity. Time-dependent flow rates obtained from the test system can be used to determine hydraulic parameters, such as energy grade lines, with the help of basic theorems of pipe hydraulics in theoretical hydraulic models. Moreover, the erosion rates were quantitatively determined using the continuity equation, while critical shear stresses were qualitatively compared for concentrated leak erosion developed by the dispersion mechanism. As a result of the experiments, stress conditions influence the concentrated leak erosion resistance in the soil samples with dispersive erosion. Moreover, the shear strength in the Mohr–Coulomb hypothesis can explain the erosion resistance in these soils under stress conditions depending on the sand/clay ratio.

Single Injection AAV2-FGF18 Gene Therapy Reduces Cartilage Loss and Subchondral Bone Damage in a Mechanically Induced Model of Osteoarthritis.

Osteoarthritis (OA) is a highly debilitating, degenerative pathology of cartilaginous joints affecting over 500 million people worldwide. The global economic burden of OA is estimated at $260-519 billion and growing, driven by aging global population and increasing rates of obesity. To date, only the multi-injection chondroanabolic treatment regimen of Fibroblast Growth Factor 18 (FGF18) has demonstrated clinically meaningful disease-modifying efficacy in placebo-controlled human trials. Our work focuses on the development of a novel single injection disease-modifying gene therapy, based on FGF18's chondroanabolic activity. OA was induced in Sprague-Dawley rats using destabilization of the medial meniscus (DMM) (3 weeks), followed by intra-articular treatment with 3 dose levels of AAV2-FGF18, rh- FGF18 protein, and PBS. Durability, redosability, and biodistribution were measured by quantifying nLuc reporter bioluminescence. Transcriptomic analysis was performed by RNA-seq on cultured human chondrocytes and rat knee joints. Morphological analysis was performed on knee joints stained with Safranin O/Fast Green and anti-PRG antibody. Dose-dependent reductions in cartilage defect size were observed in the AAV2-FGF18- treated joints relative to the vehicle control. Total defect width was reduced by up to 76% and cartilage thickness in the thinnest zone was increased by up to 106%. Morphologically, the vehicle- treated joints exhibited pronounced degeneration, ranging from severe cartilage erosion and bone void formation, to subchondral bone remodeling and near-complete subchondral bone collapse. In contrast, AAV2-FGF18-treated joints appeared more anatomically normal, with only regional glycosaminoglycan loss and marginal cartilage erosion. While effective at reducing cartilage lesions, treatment with rhFGF18 injections resulted in significant joint swelling (19% increase in diameter), as well as a decrease in PRG4 staining uniformity and intensity. In contrast to early-timepoint in vitro RNA-seq analysis, which showed a high degree of concordance between protein- and gene therapy-treated chondrocytes, in vivo transcriptomic analysis, revealed few gene expression changes following protein treatment. On the other hand, the gene therapy treatment exhibited a high degree of durability and localization over the study period, upregulating several chondroanabolic genes while downregulating OA- and fibrocartilage-associated markers. FGF18 gene therapy treatment of OA joints can provide benefits to both cartilage and subchondral bone, with a high degree of localization and durability.

Modeling and Mapping Water Erosion Risk via GIS, Remote Sensing, and the PAP/RAC Model - Case of Tamdrost Watershed, Morocco

Water erosion remains the main form of land degradation globally, with a particularly high sensitivity in Morocco. This study aims to assess and map areas at risk of water erosion in the Tamdroust watershed (Settat Plateau, Morocco) using the PAP/RAC model combined with Geographic Information Systems (GIS) and remote sensing. This comprehensive approach integrates several factors influencing erosion, such as topography, lithology, vegetation density, and land use, to identify erosion-prone areas. The methodology comprises three phases.The first, "predictive" phase generates a synthesized map illustrating the distribution of erosion states. The second phase spatializes different forms of erosion. Finally, the third phase integrates the results of the first two phases. The first phase reveals an abundance of moderate erosion covering 52% of the area, with significant erosion observed in about 7% of the watershed, indicating a trend towards increased erosion without intervention. The subsequent phases identified several forms of erosion such as sheet erosion, gully erosion, solifluction, and Badlands, mainly in areas with steep slopes and low vegetation cover. These results underline the need for interventions to prevent further deterioration of the Tamdroust watershed, highlighting the importance of sustainable land and water resource management in the region.