Natural Processing Research Articles

Effective dipole model for electrostatic interactions between polarizable spherical particles in particle scale simulations.

Despite their widespread adoption, particle-scale simulation methods, such as the Discrete Element Method (DEM), for electrically charged particles in several natural processes and industrial transformations do not include realistic polarization effects. At close distances, these can dominate the particle motion and are impossible to predict by the commonly adopted Coulomb point-charge approximation. Sophisticated mathematical tools can account for uneven charge distributions, predicting an attractive force between a charged particle and a neutral particle or possible attraction between two like-charged particles. Such approaches are accurate but too complex for implementation in DEM simulations of many interacting particles. We propose a novel, simpler yet realistically accurate effective dipole model. By attributing a net charge and an induced effective dipole to each sphere, the interaction force between charged polarizable particles is computed in closed form. A comparison of a rigorous solution and the proposed dipole approach for two spherical particles reveals significant improvement over the commonly employed Coulomb law. The effects of particle size ratio and charge ratio on the interaction force are discussed. Then, the dynamic DEM simulation of a shaker filled with a binary mixture of differently sized particles that are all positively charged is shown to predict the counterintuitive formation of fine-on-coarse aggregates.

Beyond CO2 Storage: Enzyme-Amyloid Fibril Catalytic Hybrids for Long Cascade Reactions Converting CO2 into Fructose.

Enzyme immobilization is an efficient and cost-effective approach to recovering, stabilizing, and enhancing enzyme catalytic properties. It is a challenge, however, for coimmobilized multiple enzymes to perform consecutive reactions without being inactivated under similar conditions. Here, we present a facile enzyme immobilization platform using β-lactoglobulin amyloid fibril hydrogels. Two different hydrogels, loading either RuBisCO alone (hereby termed AFR*) or seven enzymes related to the Calvin Cycle (hereby termed AF7E hydrogel), show immobilization efficiency of over ∼95% while simultaneously exhibiting excellent activity and stability. The AFR* hydrogel enables the fixation of CO2 into 3-phosphoglycerate (3-PGA), which is then utilized as the initial step in the Calvin Cycle cascade catalytic reactions if the AF7E hydrogel is used, mimicking the light-independent part of the more complex natural photosynthesis full process. The converted substrates of this process contain precursors (α-glycerophosphate dehydrogenase and dihydroxyacetone phosphate), which can be further converted to fructose by additional aldolase. Due to the proteinaceous nature of the amyloid substrate, the AF7E hydrogel is completely biodegradable by pepsin, as confirmed via atomic force microscopy and circular dichroism spectroscopy analysis. This original enzyme-amyloid hybrid is biocompatible, sustainable, and scalable and may serve as a general template for multienzymatic catalytic platforms.

Preparation of Highly Stable Wood with Fast Curing, Ultraviolet, and Mildew Resistance through Copper-Montmorillonite Nanoparticles Hybridized with Tung Oil.

Wood has a number of undesirable inherent properties that limit its ability to be used in a wider range of applications. For this reason, in this study, copper-montmorillonite nanoparticles were prepared from natural biomass tung oil and the natural mineral montmorillonite by the ion exchange method. Modified wood with tung oil intercalated with copper-montmorillonite was prepared by a simple and environmentally friendly impregnation and natural curing process. The natural curing rate of tung oil was greatly accelerated by the addition of copper-montmorillonite nanoparticles. The surface contact angle of the wood increased from 85.0° to 152.2° after copper-montmorillonite-tung oil treatment, and remarkably, it remained at 144.2° after 180 s. After 192 h of immersion, the water absorption decreased by 90.0% compared with the control group, of which the resistance to swelling was as high as 59.00%, which significantly improved the dimensional stability of the wood. After 15 days of ultraviolet irradiation, the copper-montmorillonite-tung oil-treated wood showed a 68.89% reduction in redness value compared to the control and a significant increase in ultraviolet resistance. Copper-montmorillonite-tung oil-treated wood showed greatly enhanced effectiveness against mildew. On the eighth day of Aspergillus niger infestation, the control wood was already full of mildew, whereas the copper-montmorillonite-tung oil-treated wood was not infested with mildew. In particular, after 28 days of infestation by Penicillium oryzae, the modified wood remained free of the fungus, with 100% mildew prevention efficiency. In addition, after 2 weeks of leaching, the leaching rate of the impregnated material was only 0.22%, facilitating long-term protection of the wood. The present study by the copper-montmorillonite synergistic tung oil treatment strategy provides innovative methods and potential ideas for extending the service life of wood products and high-value utilization of wood and also has the potential to scale up wood protection.

Spatio-temporal analysis of formaldehyde and its association with atmospheric and environmental variables over the Southeast Asian region using satellite data.

This study investigates the spatio-temporal distribution of formaldehyde (HCHO) over the mainland Southeast Asian region (including Northeast India) from 2019 to 2022 using TROPOMI satellite data. HCHO is a key atmospheric trace gas which is influenced by both natural processes and anthropogenic activities. We analyze HCHO levels in relation to atmospheric species including carbon monoxide (CO), nitrogen dioxide (NO2), and environmental factors such as land surface temperature (LST), precipitation (PPT), fire radiative power (FRP), and enhanced vegetation index (EVI). Peak levels of HCHO are particularly observed in March and April, which coincide with the dry and warm seasons and reflect seasonal variability arising from both fluctuating emission sources and regional climate patterns. Correlation analyses reveal significant associations between HCHO and CO (r = 0.727), followed by HCHO and NO2 (r = 0.577) and HCHO and LST (r = 0.539). Conversely, a negative correlation with PPT (r = - 0.233) is observed as HCHO decreases with increased precipitation due to washout. The negative correlation with EVI (r = - 0.319) is unexpected since biogenic emissions are significant contributors to HCHO. This outcome likely results from the confounding effect of precipitation. A robust multiple regression model incorporating these variables is developed which is able to explain 61.8% of the variance in HCHO. It enhances predictive capabilities facilitating the estimation of HCHO distribution and supporting air quality management efforts in the region. This research contributes to understanding the complex interactions of HCHO with atmospheric chemistry and climate variability in Southeast Asia. Insights gained from this study are crucial for informing environmental policies aimed at reducing air pollution and protecting public health in rapidly developing regions.

Characterisation of environmentally persistent free radicals and their contributions to oxidative potential and reactive oxygen species in sea spray and size-resolved ambient particles

Aerosols, derived from natural processes and human activities, present various risks to the environment and human health. In this regard, the role of recent pollutant environmentally persistent free radicals (EPFRs) should not be overlooked. However, the oxidative toxicity and mass transfer processes of EPFRs in liquid-phase environments remain completely understood. In this study, the dispersion characteristics of EPFRs and their contributions to the oxidation potential (OP) and reactive oxygen species (ROS) in sea spray and size-resolved PM were investigated and compared. The results showed that the sea spray contained fast-decaying C-centred EPFRs with a half-life of 0.32 years. The concentration ranged from 0.3 × 1013 spins/m3 to 7.5 × 1013 spins/m3. It increased as the samples approached the coast. Moreover, the size-resolved PM contained slow-decaying O-centred EPFRs with a half-life of 0.51 years. The concentration ranged from 4.57 × 1013 spins/m3 to 11.46 × 1013 spins/m3, which was higher than that of most sea spray samples. The interaction between sea spray and water mainly generated hydroxyl free radicals (54 ± 3%), whereas the size-resolved PM mainly generated organic free radicals (64 ± 5%). Correlation analysis revealed that EPFRs may be involved in ROS generation. In addition, the mass transfer of EPFRs between the PM and sea spray may have been controlled by both gas and liquid films. The concentration of EPFRs at the phase interface was calculated to be 4.92 × 1013 spins/m3. In summary, EPFRs positively contribute to OP and ROS production.

Shallow groundwater near a deep-well CO2 storage site-15years of stable water quality for agricultural use.

Injecting CO2 into deep geological formations can be an effective carbon removal and storage technology to mitigate global climate change. Interaction of injected CO2 with rock formations changes pH and hydrochemistry within the deep injection zone (> 800m depth). However, cap rocks and multiple tight aquitards typically act as barriers to protect the shallow aquifer from changes in the injection zone. Monitoring and evaluation of shallow groundwater quality are essential to verify that carbon capture storage projects (CCS) do not impact the near-surface environment. This study investigated shallow groundwater quality using long-term data (2006-2023) from a regular monitoring program at the Otway International Test Centre (OITC) in Victoria, Australia. It was found that shallow groundwater quality was stable over at least 15years, during which time three phases of CO2 injection into a deep storage zone occurred. The results highlighted groundwater quality complied with guidelines of Food and Agriculture Organization (FAO) and Australian water quality guidelines. Minor and localised changes observed in salinity or pH in shallow monitoring piezometers were caused by natural processes. Moreover, a wide range of groundwater quality indicators were evaluated. The results demonstrated that the groundwater quality of shallow aquifers (< 80m) at OITC is suitable for agriculture. The study provides assurance and confidence to stakeholders that the quality of the near-surface environment has not been impacted by CO2 injection into confined formations and no pollution has been detected. Although numerous CCS sites around the world are subject to monitoring, no evidence of changes in shallow groundwater quality has been reported that could be traced to CO2 injection in confined formations at > 800m depth.

Recent advances on dioxin and furan (dibenzofuran) based pollutants from analytical, environmental, and health perspectives.

Dioxins and analogous derivatives pose significant concerns due to their impact on human health through both acute and prolonged exposures. They have the potential to resist natural degradation processes; therefore, they tend to accumulate in water, sediments, fish, meat, and human adipose tissue. As a result, concerns to both environmental and human health arise among the scientific community and environmental health organizers. Herein, we provide a comprehensive review highlighting recent findings of dioxin and furan pollution with a focus on major environmental and health aspects associated with the exposure to dioxin and its derivatives by assessing the routes of exposure, toxicity, and modes of action. Moreover, VOSviewer was used to understand the research interest within the scientific community in the study of dioxins and furans. Various strategies like remediation, methods of extraction and analysis, as well as protocols required to improve compound filtration and mineralization to enhance the efficiency of environmental cleanup processes.

Optimizing FACTS Device Placement Using the Fata Morgana Algorithm: A Cost and Power Loss Minimization Approach in Uncertain Load Scenario-Based Systems

Today, reliable power delivery and increasing demand are important issues in modern power systems. Flexible Alternating Current Transmission Systems (FACTS) devices are used to control transmission line parameters to increase power transfer and stability. Nevertheless, the problem of determining the optimal placement and sizing of these devices is still challenging, as the placement and sizing of the devices affects generation costs, power losses, voltage stability, and system reliability. This study proposes the Fata Morgana Algorithm (FATA), an optimization algorithm inspired by the natural process of mirage formation to optimize placement and sizing of FACTS devices in an IEEE 30 bus system with wind turbine integration. The FATA algorithm is evaluated against recently developed and improved optimization techniques, such as rime-ice formation phenomenon based Improved RIME (IRIME) Algorithm, Newton–Raphson-Based Optimization (NRBO), Resistance Capacitance Algorithm (RCA), Krill Optimization Algorithm (KOA), and Grey Wolf Optimizer (GWO), across multiple optimization objectives: reduction in generation cost, reduction in power loss and combined generation cost plus power loss, termed as Gross cost function. Results obtained show that FATA consistently outperforms the other algorithms in terms of convergence and solution quality, offering a robust approach to solving single objective optimization problems. FATA theoretically provides a good balance between exploration and exploitation, and produces better global solutions. It practically increases power system efficiency by lowering operational costs and losses and improving stability. Results indicate that the FATA algorithm produced minimum generation cost of 807.0405 $/h, which is 0.088–0.426% less than the competing algorithms. It also reduced power losses to 5.5917 MW, which is 1.095–6.781% less than other methods. For gross cost minimization, the FATA algorithm achieved a minimum gross cost of 1366.3727 $/h, which is 0.4799% better than the next best algorithm and 3.2261% better than the worst. The results also show that FATA is robust in solving complex optimization problems in power systems, and it provides significant improvements in run time and convergence efficiency. The main advantage for readers is that FATA provides a reliable and efficient way to optimize power systems. Future work could also investigate the application of FATA in real time, as well as in larger power networks with more renewable energy sources.

EEG reveals brain network alterations in chronic aphasia during natural speech listening

Aphasia is a common consequence of a stroke which affects language processing. In search of an objective biomarker for aphasia, we used EEG to investigate how functional network patterns in the cortex are affected in persons with post-stroke chronic aphasia (PWA) compared to healthy controls (HC) while they are listening to a story. EEG was recorded from 22 HC and 27 PWA while they listened to a 25-min-long story. Functional connectivity between scalp regions was measured with the weighted phase lag index. The Network-Based Statistics toolbox was used to detect altered network patterns and to investigate correlations with behavioural tests within the aphasia group. Differences in network geometry were assessed by means of graph theory and a targeted node-attack approach. Group-classification accuracy was obtained with a support vector machine classifier. PWA showed stronger inter-hemispheric connectivity compared to HC in the theta-band (4.5–7 Hz), whilst a weaker subnetwork emerged in the low-gamma band (30.5–49 Hz). Two subnetworks correlated with semantic fluency in PWA respectively in delta- (1–4 Hz) and low-gamma-bands. In the theta-band network, graph alterations in PWA emerged at both local and global level, whilst only local changes were found in the low-gamma-band network. Network metrics discriminated PWA and HC with AUC = 83%. Overall, we demonstrate the potential of EEG-network metrics for the development of informative biomarkers to assess natural speech processing in chronic aphasia. We hypothesize that the detected alterations reflect compensatory mechanisms associated with recovery.

Deferasirox improved iron homeostasis and hematopoiesis in ovariectomized rats with iron accumulation

Menopause is a natural biological aging process characterized by the loss of ovarian follicular function and decrease estrogen levels. These hormonal fluctuations are associated with increased iron levels, which ultimately lead to iron accumulation. This study aims to investigate the effects of Deferasirox on iron homeostasis and hematopoiesis in ovariectomized rats with iron accumulation. Sixty-four female Wistar rats were divided into eight groups and underwent ovariectomy surgery to simulate menopause. Iron accumulation was induced through the injection of ammonium ferric citrate. Deferasirox was administered at doses of 50 mg/kg and 100 mg/kg. Hematological parameters, iron profile, antioxidant markers, oxidative stress indicators, histopathological evaluation of uterine, bone, bone marrow, liver, and spleen tissues, flow cytometric analysis of hematopoietic CD markers, and relative expression of Hamp, Pu.1, Gata1, and Gdf11 genes were analyzed. Deferasirox treatment improved histopathological changes in the uterine tissue of ovariectomized rats with iron accumulation, increased the number of white blood cells, and reduced serum iron levels, TIBC, ferritin, and transferrin saturation percentage. It also increased serum antioxidant capacity and reduced oxidative stress markers. Deferasirox had a positive effect on femur bone, hematopoietic cell count, volume of hematopoietic and adipose tissues in bone marrow, extramedullary hematopoiesis in the liver and spleen, and influenced the relative expression of Hamp, Pu.1, Gata1, and Gdf11 genes related to hematopoiesis and iron metabolism. In conclusion, Deferasirox effectively manages iron homeostasis and hematopoiesis in ovariectomized rats with iron accumulation and suppresses oxidative stress.

Towards negative carbon footprint: carbon sequestration enabled manufacturing of coral-inspired tough structural composites

The increasing impacts of global warming necessitate effective mitigation strategies, with carbon sequestration emerging as a viable mid-term solution. Traditional methods focus on storing CO2 or converting it into liquid substances. However, natural processes like those found in corals demonstrate superior capabilities by transforming CO2 into robust, load-bearing solids with exceptional mechanical properties. Inspired by coral’s biomineralization, this study introduces an electrochemical manufacturing method that converts CO2 into calcium carbonate minerals around 3D-printed polymer scaffolds. This approach results in mineral-polymer composites characterized by extraordinary mechanical strength and fracture toughness, fire resistance, and crack repairability. These composites also offer structure-programmability and composition-reversibility. The scalable modular assembly of these composites supports the creation of larger-scale, load-bearing meso-structures. This manufacturing paradigm promotes negative carbon footprint practices, paving the way for sustainable engineering solutions and a more environmentally friendly future.

Terrestrial nanoparticles and geospatial optics: Implications for environmental impact from anthropogenic contaminants in the Caribbean region.

Atmospheric contaminants from natural processes and anthropogenic activities pose a major problem to the environment. Here we analyze the dynamics of atmospheric and terrestrial contaminant concentrations in sediments containing chemical elements, such as nanoparticles (NPs) and ultrafine particles in hydrological sources of the Caribbean region of Colombia. Terrestrial sediments were collected from 2022 to 2024, and quantified for major chemical elements in the form of NPs and ultrafine particles in runoff receiving areas along the banks of Colombia's Ciénaga Grande in Santa Marta Bay, on the Isla de Salamanca. Additionally, atmospheric carbon monoxide (CO) and nitrogen dioxide (NO2) levels were detected using TROPOMI, coupled with the Sentinel-5P satellite, from 2019 to 2024. Sampling was performed during both summer and winter, focusing on the Sierra Nevada de Santa Marta National Park, Isla de Salamanca, and the cities of Santa Marta and Barranquilla. Sediment samples were collected from 25 fixed sites on Isla de Salamanca and analyzed in the laboratory. The CO and NO2 concentrations were detected at 122 "collection points," with a spatial resolution of 7km×3.5km, an average normalization of 0.83μg/mg, and a maximum error of 6.62%. The results revealed abundant Fe particles containing Cr, Ti, Zn, and Zr (1-2.5μm in size), with nanohematite (iron oxide) particles containing C, As, and S detected via EDS. The CO concentrations peaked in Barranquilla and Santa Marta (up to 0.042mol/m2), while NO2 concentrations reached 2.4×10-5 mol/m2, similar to the levels in Sierra Nevada de Santa Marta National Park and Ciénaga Grande de Santa Marta. These findings highlight the impact of forest fires on air quality in the region and support the development of new public policies to mitigate pollution and to protect ecosystems in this ecologically relevant area.

Bioinspired Assembly of Natural Polyphenol-Amino Acid Surfactants as Multifunctional Durable Coatings for Anticorrosion Fruit Packaging.

Challenges emerge in the quest for highly efficient and biocompatible coatings to tackle microbial contamination. Here, we propose a bioinspired paradigm combining (-)-epigallocatechin gallate (EGCG) and l-arginine surfactants (LAM) as all-green building blocks for advanced coatings with superior performance. Molecular dynamics simulations reveal the natural assembly process of the EGCG/LAM supramolecular nanoparticles (ELA NPs). Notably, the coatings retain 99.0% antimicrobial activity even after eight cycles of use and exhibit highly adhesive and anti-water washing properties, maintaining their efficacy after eight uses and 30 days of water soaking on various substrates. When applied as sustainable food packaging coatings for perishable fruits at room temperature, the ELA coatings significantly extend the shelf life of strawberries and cherry tomatoes, reducing weight loss and maintaining firmness and sweetness. This study demonstrates the potential of ELA NPs as versatile and durable coating materials for mitigating food waste and agricultural economic losses due to microbial pollution.

The Role of Acupuncture and Stem Cell Therapy in Enhancing Stroke Recovery

Stroke is an acute neurological disorder caused by disrupted blood flow to the brain, depriving cells of oxygen. From 1990 to 2019, it was the world’s second-leading cause of death and the third-leading cause of combined death and disability. Acupuncture plays a role in stem cell treatment by activating the body's natural recovery processes through physical stimulation, aiding the recovery and rehabilitation of stroke patients. Several studies have explored combining stem cell therapy with acupuncture, yielding promising results in improving patient outcomes. This review assesses the effectiveness of combining acupuncture with stem cell therapy for stroke recovery. Analysis of seven randomized controlled trials shows that both stem cell transplantation and acupuncture contribute to the rehabilitation of stroke patients. When applied together, this combined therapy improves the survival, retention, and functional differentiation of implanted stem cells, creating a synergistic effect that amplifies the benefits of each treatment and compensates for their individual limitations. Key acupuncture points for this combination therapy include GV20, GV14, LI11, ST36, and GV26, with treatment durations ranging from 10 to 22 days.

Bone Enzyme-Responsive Biodegradable Poly(propylene fumarate) and Polycaprolactone Polyphosphoester Dendrimer Cross-Linked via Click Chemistry for Bone Tissue Engineering.

Traditional polymer systems often rely on toxic initiators or catalysts for cross-linking, posing significant safety risks. For bone tissue engineering, another issue is that the scaffolds often take a longer time to degrade, inconsistent with bone formation pace. Here, we developed an enzyme-responsive biodegradable poly(propylene fumarate) (PPF) and polycaprolactone (PCL) polyphosphoester (PPE) dendrimer cross-linked utilizing click chemistry (EnzDeg-click-PFCLPE scaffold) for enhanced biocompatibility and degradation. The strain-promoted alkyne-azide cycloaddition (SPAAC) offers high efficiency and biocompatibility without harmful agents. The polyphosphoesters render polymer cleavage responsive to alkaline phosphatase (ALP) enzyme in bone formation, ensuring facilitated scaffold biodegradation. The in vitro testing confirmed biocompatibility, enzyme-responsive degradation, and capability to support stem cell differentiation. Further in vivo implantation in rat demonstrated bone regeneration and scaffold integration. In summary, this polymer system combining click chemistry with ALP-responsive biodegradation ensures initial bone support and facilitates scaffold degradation synchronized with the natural bone healing process.

Nucleic acid recognition during prokaryotic immunity.

Parasitic elements often spread to hosts through the delivery of their nucleic acids to the recipient. This is particularly true for the primary parasites of bacteria, bacteriophages (phages) and plasmids. Although bacterial immune systems can sense a diverse set of infection signals, such as a protein unique to the invader or the disruption of natural host processes, phage and plasmid nucleic acids represent some of the most common molecules that are recognized as foreign to initiate defense. In this review, we will discuss the various elements of invader nucleic acids that can be distinguished by bacterial host immune systems as "non-self" and how this signal is relayed to activate an immune response.

Gypsum heterogenous nucleation pathways regulated by surface functional groups and hydrophobicity

Gypsum (CaSO4·2H2O) plays a critical role in numerous natural and industrial processes. Nevertheless, the underlying mechanisms governing the formation of gypsum crystals on surfaces with diverse chemical properties remain poorly understood due to a lack of sufficient temporal-spatial resolution. Herein, we use in situ microscopy to investigate the real-time gypsum nucleation on self-assembled monolayers (SAMs) terminated with −CH3, −hybrid (a combination of NH2 and COOH), −COOH, −SO3, −NH3, and −OH functional groups. We report that the rate of gypsum formation is regulated by the surface functional groups and hydrophobicity, in the order of −CH3 > −hybrid > −COOH > −SO3 ≈ − NH3 > − OH. Results based on classical nucleation theory and molecular dynamics simulations reveal that nucleation pathways for hydrophilic surfaces involve surface-induced nucleation, with ion adsorption sites (i.e., functional groups) serving as anchors to facilitate the growth of vertically oriented clusters. Conversely, hydrophobic surfaces involve bulk nucleation with ions near the surface that coalesce into larger horizontal clusters. These findings provide new insights into the spatial and temporal characteristics of gypsum formation on various surfaces and highlight the significance of surface functional groups and hydrophobicity in governing gypsum formation mechanisms, while also acknowledging the possibility of alternative nucleation pathways due to the limitations of experimental techniques.

MXene Hollow Microsphere-Boosted Nanocomposite Electrodes for Thermocells with Enhanced Thermal Energy Harvesting Capability.

Thermal energy, constantly being produced in natural and industrial processes, constitutes a significant portion of energy lost through various inefficiencies. Employing the thermogalvanic effect, thermocells (TECs) can directly convert thermal energy into electricity, representing a promising energy-conversion technology for efficient, low-grade heat harvesting. However, the use of high-cost platinum electrodes in TECs has severely limited their widespread adoption, highlighting the need for more cost-effective alternatives that maintain comparable thermoelectrochemical performance. In this study, a nanocomposite electrode featuring Ti3C2Tx with hollow microsphere structures is rationally designed. This design addresses the restacking issue inherent in MXene nanosheets, increases the electrochemically active surface area, and modifies the original MXene surfaces with oxygen terminations, leading to improved redox kinetics at the electrode-electrolyte interface, particularly in n-type TECs employing Fe2+/3+ redox ions. The optimized n-type TEC achieved an output power of 84.55 μW cm-2 and a normalized power density of 0.53 mW m-2 K-2 under a ΔT of 40 K, outperforming noble platinum-based TECs by a factor of 5.5. An integrated device consisting of 32 TEC units with a p-n connection is also fabricated, which can be successfully utilized to power various small electronics. These results demonstrate the potential of MXene-based composite electrodes to revolutionize TEC technology by offering a cost-effective, high-performance alternative to traditional noble metal electrodes and contributing to efficient low-grade heat harvesting.

Sources, Water Quality, and Potential Risk Assessment of Heavy Metal Contamination in Typical Megacity River: Insights from Monte Carlo Simulation

Due to the intense human activities and rapid development of economy, dissolved heavy metals (DHMs) pose a significant threat to urban river ecosystems. Therefore, the distribution, sources, and potential risks of DHMs in the Chaobai River (typical urban river) were investigated via ICP-MS in detail. Results revealed considerable spatial heterogeneity of heavy metals with various concentrations from the upper to lower reach. Principal component analysis (PCA) revealed that V, Ni, As, Mo, and Pb mainly originated from a mixing process of industrial input and natural process, Cr and Cu were mainly derived from urban activities, and Zn was mainly influenced by agriculture activities. Furthermore, land use types within the buffer zone near sampling points were innovatively analyzed, revealing strong correlations between DHMs and regional land use patterns. Monte Carlo simulations were employed to assess the differentiated non-carcinogenic and carcinogenic risks associated with DHMs across four age groups. This study provided scientific references for the sustainable management of urban rivers and aquatic systems in such a megacity region.

A scalable and modular reservoir implementation for large-scale integrated hydrologic simulations

Abstract. Recent advancements in integrated hydrologic modeling have enabled increasingly high-fidelity models of the complete terrestrial hydrologic cycle. These advances are critical for our ability to understand and predict watershed dynamics, especially in a changing climate. However, many of the most physically rigorous models have been designed to focus on natural processes and do not incorporate the effect of human-built structures such as dams. By not accounting for these impacts, our models are limited both in their accuracy and in the scope of the topics they are able to investigate. Here, we present the first implementation of dams and reservoirs in ParFlow, an integrated hydrologic model. Through a series of idealized and real-world test cases, we demonstrate that our implementation (1) functions as intended, (2) maintains important qualities such as mass conservation, (3) works in a real domain, and (4) is computationally efficient and can be scaled to large domains with thousands of reservoirs. Our results have the potential to improve the accuracy of current ParFlow models and enable us to ask new questions regarding conjunctive management of ground and surface water in systems with reservoirs.