Distribution Patterns Research Articles

Attenuated kidney oxidative metabolism in young adults with type 1 diabetes.

In type 1 diabetes (T1D), impaired insulin sensitivity may contribute to the development of diabetic kidney disease (DKD) through alterations in kidney oxidative metabolism. Young adults with T1D (n = 30) and healthy controls (HC, n = 20) underwent hyperinsulinemic-euglycemic clamp studies, MRI, 11C-acetate PET, kidney biopsies, single-cell RNA sequencing, and spatial metabolomics to assess this relationship. Participants with T1D had significantly higher glomerular basement membrane thickness compared to HC. T1D participants exhibited lower insulin sensitivity and cortical oxidative metabolism, correlating with higher insulin sensitivity. Proximal tubular transcripts of TCA cycle and oxidative phosphorylation enzymes were lower in T1D. Spatial metabolomics showed reductions in tubular TCA cycle intermediates, indicating mitochondrial dysfunction. The Slingshot algorithm identified a lineage of proximal tubular cells progressing from stable to adaptive/maladaptive subtypes, using pseudotime trajectory analysis, which computationally orders cells along a continuum of states. This analysis revealed distinct distribution patterns between T1D and HC, with attenuated oxidative metabolism in T1D attributed to a greater proportion of adaptive/maladaptive subtypes with low expression of TCA cycle and oxidative phosphorylation transcripts. Pseudotime progression associated with higher HbA1c, BMI, GBM, and lower insulin sensitivity and cortical oxidative metabolism. These early structural and metabolic changes in T1D kidneys may precede clinical DKD. gov NCT04074668.

Delineation of Management Zones for Site‐Specific Soil Nutrient Management for Sustainable Crop Production

ABSTRACTSoil nutrients deficiencies are one of the major causes of soil degradation in different parts of World, adversely impacting crop production. Delineation of soil nutrients management zones (MZs) is one of the commonly used techniques for evaluating spatial distribution pattern of soil parameters for adoption of site‐specific nutrient management. We, therefore, conducted the present study to understand the spatial distribution pattern of soil nutrients and their associated soil properties, and to delineate soil nutrients MZs in a north‐western Indian Himalayan (NWIH) region. A total of 18,930 representative surface (0–15 cm depth) soil samples were collected and processed. The processed soil sample were analyzed for pH, and electrical conductivity (EC), soil organic carbon (SOC), available N (AN), available P (AP), available potassium (AK), exchangeable Ca (Ex. Ca), exchangeable Mg (Ex. Mg), available S (AS), available Zn (AZn), available Fe (AFe), available Cu (ACu), available Mn (AMn) and available B (AB). The values of studied soil parameters varied widely with coefficient of variation ranging from 11.8% to 156%. Semivariogram analysis revealed stable, exponential and Gaussian best‐fit models for different soil parameters with weak (AP and AB), moderate (rest of soil parameters) and strong (AS) spatial dependence. Varied distribution pattern of soil parameters was visualized from ordinary kriging interpolation. Five soil nutrient management zones (MZs) were identified (using fuzzy performance index and normalized classification entropy values) by employing the techniques of principal component analysis and fuzzy c‐means clustering. Principal components with Eigen value > 1 were considered for further analysis. The soil parameters of identified MZs differed significantly. Thus, the study highlighted the usefulness of MZ delineation technique for site‐specific soil nutrient management in different cultivated areas for sustainable crop production. The developed MZ maps could suitably be used for efficient management of agronomic inputs especially fertilizer nutrients for improved environmental and economic efficiency.

Analyzing the distribution patterns and dynamic niche of Magnolia grandiflora L. in the United States and China in response to climate change

IntroductionMagnolia grandiflora L. (southern magnolia) is native to the southeastern coastal areas of the United States, from North Carolina to eastern Texas (USDA Cold Hardiness Zone 8). It is currently widely cultivated in Zones 5-10 in the U.S. and in southern Yangtze River regions in China. Limited studies have examined the effects of climate change and human activities on the geographical distribution and adaptability of M. grandiflora during its introduction to China.MethodsWe selected 127 occurrence points in the U.S. and 87 occurrence points in China, along with 43 environmental variables, to predict suitable habitat areas for M. grandiflora using present climate data (1970-2000) and projected future climate data (2050-2070) based on a complete niche ensemble model (EM) using the Biomod2 package. We also predicted the niche change of M. grandiflora in both countries using the 'ecospat' package in R.ResultsThe ensemble models demonstrated high reliability, with an AUC of 0.993 and TSS of 0.932. Solar radiation in July, human impact index, and precipitation of the wettest month were identified as the most critical variables influencing M. grandiflora distribution. The species shows a similar trend of distribution expansion under climate change scenarios in both countries, with predicted expansions towards the northwest and northeast, and contractions in southern regions.DiscussionOur study emphasizes a practical framework for predicting suitable habitats and migration of Magnoliaceae species under climate change scenarios. These findings provide valuable insights. for species conservation, introduction, management strategies, and sustainable utilization of M. grandiflora.

Non-Conventional Data for Farming-Related Air Pollution: Contributions to Modelling and Risk Assessment in the Lombardy Region, Italy

Air pollution is one of the most critical global health concerns today. While emissions from industrial activities and combustion processes are the primary threats to air quality, intensive farming activities also contribute significantly, especially through ammonia emissions that promote the formation of secondary pollutants, such as particulate matter. Advancements in air quality research have been achieved by enhancements in emissions characterisation, modelling techniques, and sensor technology, expanding the availability of air pollution data beyond traditional ground sensor observations, which are often lacking in rural agricultural areas. Accordingly, this paper demonstrates the advantages of integrating traditional and non-conventional data to investigate farming-related air pollution through a case study in the Lombardy Region, Northern Italy. The study incorporates an array of data sources, including ground sensors and atmospheric composition model estimates. The concurrent utilisation of these diverse datasets is explored through machine learning modelling, focusing on assessing the influence of agricultural activities on particulate matter distribution patterns. Finally, the reliability of non-conventional air pollution data for health risk assessment applications is also investigated. The paper critically discusses the main findings based on empirical results, highlighting the significance of integrating multiple data sources to complement traditional air quality monitoring while outlining the main limitations in terms of the accuracy and usability of such non-conventional data.

Explaining Environmental Distribution of Aedes albopictus using Machine Learning

Abstract. The Aedes albopictus mosquito, known for its role in transmitting diseases such as dengue fever, Zika virus, and chikungunya, poses a significant public health threat globally. Understanding its distribution patterns is crucial for effective disease surveillance and control. This study employs machine learning techniques, specifically MaxEnt modeling, to elucidate the relationship between environmental factors and the distribution of Aedes albopictus. Using presence-only data and a suite of environmental variables, we trained MaxEnt models to predict the potential distribution of Aedes albopictus across a geographical region. The models were validated using independent datasets and evaluated for their predictive accuracy and robustness. Our results reveal significant associations between Aedes albopictus presence and environmental factors such as temperature related variables. Furthermore, we employed spatial analysis techniques to identify areas at high risk of Aedes albopictus presence, aiding in targeted vector control strategies and disease prevention efforts. MaxEnt models demonstrated high predictive performance, effectively capturing the complex relationships between environmental variables and mosquito distribution in Nepal, India and Myanmar, along with Spain and Italy. By integrating machine learning algorithms with environmental data, this study provides valuable insights into the ecological drivers of Aedes albopictus distribution, enhancing our ability to mitigate the risk of mosquito-borne diseases in affected regions.

A new semi-analytical approach for nonlinear dynamic responses of functionally graded porous graphene platelet-reinforced circular plates and spherical shells

This paper presents the semi-analytical approach for nonlinear dynamic responses of porous graphene platelet-reinforced circular plates (CiPs) and spherical shells (SpSs) resting on the Pasternak foundation in thermal environment. The graphene platelets (GPLs) are distributed in the functionally graded (FG) distribution patterns and uniform distribution pattern through the CiP and SpS thickness direction. The governing equations of the GPL-reinforced structures subjected to time-dependent external pressure respected to the harmonic and linear functions of time are established based on the geometrically nonlinear higher-order shear deformation theory. A simple and effective semi-analytical solution for the considered problem is established using the Euler-Lagrange equations, and the damping viscosity of the foundation can be counted using the Rayleigh dispassion function. The Runge-Kutta method is employed to determine the dynamic responses of the GPL-reinforced structures, while the fundamental frequencies of free and linear vibration, and frequency-amplitude curves are obtained in explicit form. The numerical results obtained reveal that the GPL and porous distributions, geometrical and material properties can significantly affect the frequency-amplitude curves, and dynamic responses of harmonically loaded and linearly loaded structures, specially, the dynamic buckling phenomenon is clearly observable with the SpSs but not with the CiPs.

Impact of burden and distribution of aortic valve calcification on the hemodynamic performance and procedural outcomes of a self-expanding, intra-annular transcatheter aortic valve system.

Aortic valve calcification (AVC) has been explored as a powerful predictor of procedural complications in patients undergoing transcatheter aortic valve implantation (TAVI). However, little evidence exists on its impact on intra-annular devices' performance. We aimed to investigate the impact of AVC burden and distribution pattern on the occurrence of paravalvular leak (PVL), conduction disturbances requiring permanent pacemaker implantation (PPI) and 30-day clinical outcomes in patients undergoing TAVI with a self-expanding, intra-annular device. According to AVC, 103 patients enrolled in a single medical centre from November 2019 to December 2022 were divided into tertiles. Valve Academic Research Consortium (VARC)-3 definitions were used to classify procedural complications and outcomes. Patients in the highest AVC tertile showed an increased occurrence of mild or more PVL and conduction disorders (p < 0.001 and p = 0.006). AVC tertiles (highest tertile) emerged as an independent predictor of PVL (OR 7.32, 95%CI 3.10-17.28, p < 0.001) and post-TAVI conduction disturbances (OR 3.73, 95%CI 1.31-10.60, p = 0.013) but not of PPI (OR 1.44, 95%CI 0.39-5.35, p = 0.579). Considering calcium distribution, ROC analyses revealed that annular AVC but not left ventricle outflow tract (LVOT) calcium burden significantly indicated the development of PVL (AUC 0.863, 0.77-0.93, p < 0.001) and conduction disorders/PPI (AUC 0.797, 0.70-0.89, p < 0.001 and 0.723, 0.58-0.86, p = 0.018, respectively). After adjustment for age and sex, the highest tertile remained an independent predictor of the 30-day composite outcome (death, myocardial infarction, stroke, major vascular complications, type 3/4 bleedings, acute kidney injury, PPI and ≥ moderate PVL) (OR 3.26; 95%CI 1.26-8.40, p = 0.014). A higher AVC is associated with an increased risk of PVL and conduction disturbances after TAVI with a self-expanding, intra-annular device. However, our findings suggest a minor role for LVOT calcification compared with annular AVC in the performance of this specific prosthesis.

Study on the Value of Ecosystem Services and Land Use Change in the Area North of the Tianshan Mountains from 2000 to 2020

The northern Tianshans region in the arid zone of northwestern China plays a key role in promoting high-quality development of the ecological environment. In recent years, ecological environmental protection in this region has encountered major challenges due to the dual impacts of human activities and natural changes. In order to accurately assess the current status of the ecological environment in the northern Tianshans, this study analyzed the spatial and temporal changes in land use and ecological and environmental effects using land use data from 2000 to 2020 and explored the current status of land use, land use dynamic process, and ecosystem service value (ESV) in the region. Two-factor spatial autocorrelation analysis revealed the spatio-temporal characteristics of the value changes over the 20-year period as well as their spatial heterogeneity. The results show that: (1) land use changes are dominated by increases in cultivated land, forest land, watershed, and wetland, and decreases in grassland, glacier snow, and bare land. Of these changes, the expansion of cultivated land area is the most significant, showing a total increase of 1136.13 × 103 hm2. (2) The ESV increased and then decreased, reaching the highest value in 2005 and the lowest in 2020. The value of individual ecosystem services is dominated by regulating services, accounting for about 67% of the total value. (3) The overall regional balance of ecological environment quality and the contribution rate of the conversion from bare land to other land types is as high as 82.7986%, constituting the main factor in regional ecological environment improvement. The spatial distribution pattern exhibits the characteristic of “high in the northeast and low in the southwest”. (4) There is a positive correlation between the ESV, the Normalized Difference Vegetation Index (NDVI), and the Anthropogenic Impact Composite Index, with the NDVI being the main cause of spatial heterogeneity in the ESV. The research results provide a scientific basis for ecological protection, land management, and policy formulation in the northern foothills of the Tianshan Mountains and are of great significance for promoting regional sustainable development.

Does ERA5-Land Effectively Capture Extreme Precipitation in the Yellow River Basin?

ERA5-Land is a valuable reanalysis data resource that provides near-real-time, high-resolution, multivariable data for various applications. Using daily precipitation data from 301 meteorological stations in the Yellow River Basin from 2001 to 2013 as benchmark data, this study aims to evaluate ERA5-Land’s capability of monitoring extreme precipitation. The evaluation study is conducted from three perspectives: precipitation amount, extreme precipitation indices, and characteristics of extreme precipitation events. The results show that ERA5-Land can effectively capture the spatial distribution patterns and temporal trends in precipitation and extreme precipitation; however, it also exhibits significant overestimation and underestimation errors. ERA5-Land significantly overestimates total precipitation and indices for heavy precipitation and extreme precipitation (R95pTOT and R99pTOT), with errors reaching up to 89%, but underestimates the Simple Daily Intensity Index (SDII). ERA5-Land tends to overestimate the duration of extreme precipitation events but slightly underestimates the total and average precipitation of these events. These findings provide a scientific reference for optimizing the ERA5-Land algorithm and for users in selecting data.

Statistical analysis of apparent morphology and characteristics of corroded rebars of concrete in the marine environment

The residual cross-sectional areas of corroded rebars and their uniformity are the main indexes to evaluate the safety and durability of concrete structures in the marine environment. To evaluate corrosion characteristics of naturally corroded rebars, nineteen corroded rebars were extracted from the prototype components of a high-pile wharf with 35 years of service. The apparent morphology characteristics of corroded rebars were obtained using 3D scanning. The results indicate that the corrosion is non-uniform along both the longitudinal and cross-sectional directions of the corroded rebars. In the marine environment, the residual cross-sectional areas of corroded rebars along the length adhere to a three-parameter Weibull distribution; however, no specific probability distribution model or clear correlation with the distribution pattern exists for rebars with varying corrosion degrees. The spatial heterogeneity factors of the rebars are characterized by a three-parameter Frechet distribution.

Review of Neoleptastacus Nicholls, 1945 (Harpacticoida, Arenopontiidae), including an updated key to species and proposal of Phreatipontia gen. nov.

A revision of the genus Neoleptastacus Nicholls, 1945 (Harpacticoida, Arenopontiidae) is presented, resulting in the recognition of 24 valid species. The genus is divided in five species groups based on shared morphological character states, i.e. the acanthus-, australis-, speluncae-, trisetosus- and spinicaudatus-groups with the acanthus-group being further fragmented in three subgroups (acanthus, gussoae, ornamentus). The two members of the speluncae-group, Neoleptastacus phreatica (Cottarelli, Bruno &amp; Venanzetti, 1994) and N. speluncae (Cottarelli, Bruno &amp; Venanzetti, 1994), are redescribed and transferred to a new genus, Phreatipontia gen. nov., that appears to have a preference for low salinity habitats. The Mediterranean N. acanthus (Chappuis, 1954) is redescribed based on material from Türkiye and considered potentially conspecific with N. huysi (Karanovic, 2000). The male specimen illustrated in the original description of N. longiremis (Chappuis, 1955) is designated as the lectotype to define the nominal taxon objectively in the likely event that females and males assigned to this inadequately described species turn out to be non-conspecific. Detailed morphological comparison of species currently allocated to the gussoae-complex revealed three new cryptic taxa from Central and South America which are accorded specific rank (N. abbreviatus sp. nov., N. chilensis sp. nov., and N. rectus sp. nov.). The taxonomic status of Arenopontia (Neoleptastacus) acantha accraensis Lang, 1965 sensu Kunz (1971) is reassessed based on material from Angola and described as N. emendatus sp. nov. The Panamanian material previously identified as N. trisetosus (Mielke, 1982) is considered to represent a distinct species, N. panamensis sp. nov. while N. pseudishikarianus sp. nov. is proposed for the Chilean “population” of N. ishikarianus (Itô, 1968). Neoleptastacus supersetosus sp. nov. is described from Kuwait, representing the first arenopontiid record from the Arabian Peninsula. Neoleptastacus secundus Krishnaswamy, 1957 and N. accraensis (Lang, 1965) are treated as species inquirendae while Arenopontia breviarticulata Mielke, 1975 is removed from its provisional position in Neoleptastacus and placed as species incertae sedis in the Arenopontiidae. Distribution data are summarized for each species and the previously assumed amphi-Panamanian and amphi-Pacific distribution patterns of N. gussoae (Cottarelli, 1973) and N. ishikarianus, respectively, are rejected. Updated keys to the 24 valid species of Neoleptastacus and the six genera currently recognized in the family are provided.

Altitude Distribution Patterns and Driving Factors of Rhizosphere Soil Microbial Diversity in the Mountainous and Hilly Region of Southwest, China

The distribution characteristics of the microbial community in rhizosphere soils of different altitudinal gradients were explored to uncover ecological factors affecting microbial community composition. In this study, the community variations of bacteria and fungi in the rhizosphere soil of Chrysanthemum indicum L. were analyzed. Samples were distributed along an altitudinal gradient of 300–1500 m above sea level in the Fuling watershed of the Three Gorges Reservoir area, China. The analysis was conducted using Illumina MiSeq high-throughput sequencing and bioinformatics analyses. Through correlation analysis with ecological factors, the altitude distribution pattern and driving factors of soil microbial diversity in the mountainous and hilly region of Chongqing were explored. According to the results, the richness and diversity of rhizosphere soil bacteria increased with altitude, while fungi were the richest and most diverse at an altitude of 900 m. The composition of the microbial community differed among different altitudes. Actinobacteria, Proteobacteria, Acidobacteriota, Chloroflexi, Bacteroidota, Ascomycota, unclassified_k_Fungi, Basidiomycota, and Mortierellomycota dominated the microbial community in rhizosphere soil. Correlation analysis showed that the distribution of rhizosphere soil microbial communities correlated with soil ecological factors at different altitudes. Moisture, pH, total nitrogen, total potassium, available potassium, urease, and catalase were significantly positively correlated with rhizosphere soil bacterial α-diversity, while their correlations with fungi were not significant. Variation partition analysis showed that the combined effects of soil physical and chemical factors, enzyme activity, and microbial quantity regulated bacterial community structure and composition. Their combined contributions (19.21%) were lower than the individual effects of soil physical and chemical factors (48.49%), enzyme activity (53.24%), and microbial quantity (60.38%). The effects of ecological factors on fungal communities differed: While the soil physical and chemical factors (44.43%) alone had a clear effect on fungal community structures, their combined contributions had no apparent effect. The results of this study not only contribute to a deeper understanding of the impact mechanism of altitude gradient on the diversity of rhizosphere soil microbial communities, but also provide a scientific basis for the protection and management of mountainous and hilly ecosystems. It lays a foundation for the future exploration of the relationship between microbial communities and plant–soil interactions.

Supression of Shielding Effect of Large Area Field Emitter cathode in Radio Frequency Gun environment

Abstract Using large area field emitters (LAFE) as cathodes for RF gun injectors offers significant potential for creating compact, high-power, and high-brightness electron beams, crucial for advanced accelerator technologies. However, when subjected to DC electric fields, LAFEs face significant challenges due to the shielding effect, which limits emission from central emitters and decreases overall current density. Overcoming the shielding effect in an RF gun environment is essential to meet the required beam quality in accelerators. The current distribution of LAFE under DC conditions is influenced by several geometric parameters, such as emitter height, inter-emitter distance, aspect ratio, and the number of emitters. Moreover, in an RF gun setup, LAFEs experience varying macroscopic electric fields at different emitter positions, altering the current distribution compared to DC fields. In this study, we have systematically examined the impact of various LAFE parameters on their field emission performance in an RF gun environment. We have adopted a semi-analytical approach to estimate the current distribution of LAFE, combining analytically calculated field enhancement factors (γ) with numerically calculated applied RF field values. After validating the method with COMSOL simulations, we have applied it to estimate the current distribution of an LAFE cathode integrated into a ½ cell S-band (2856 MHz) gun. The simulation results indicate that, under favorable conditions, a Gaussian spatial beam distribution can be achieved with LAFE, thus mitigating the shielding effect typical in DC fields. By optimizing various LAFE parameters, the desired current and beam distribution patterns can be attained. This study highlights a promising approach for designing LAFE cathodes for RF guns, which could advance accelerator-related technologies.&amp;#xD;

Cultivated Land Information Extraction and Spatial Pattern Analysis in Beijing Based on Deep Learning

Abstract. Cultivated land is the basic resource and material condition for human survival, providing the necessary material basis for agricultural development and agricultural modernization (Tian and Shi, 2024). For this reason, this paper takes Beijing as an experimental area to study the cultivated land extraction method and analyze the distribution pattern of cultivated land and the degree of fragmentation. The results show that (1) the extraction results are evaluated by using confusion matrix and Kappa coefficient, and the Kappa coefficient is obtained to be 0.8358.(2) The cultivated land in Beijing is mainly distributed in the southeast as well as the northwest of the local area of gentle terrain, and the The range of the extremely high value of cultivated land kernel density in 2017–2022 is significantly reduced, the slope of the area with the smallest reduction in the proportion of cultivated land is less than 5°, the reduction in the area of cultivated land in water resource-rich areas is small, and the reduction in the proportion of cultivated land in road-intensive areas is large. (3) Due to various natural factors and human activities, the degree of cultivated land fragmentation in Beijing is increasing, the boundary shape of cultivated land patches tends to be irregular.

Understanding future water-carbon-land coupled systems in the era of COP 27: The case of the Hanjiang river Basin, China

The 27th Conference of the Parties (COP 27) emphasized addressing this century's interconnected challenges of food, water, and energy. This study proposes a coupled ecosystem service and multi-scenario land-use change simulation model designed to investigate the future dynamics of water-carbon-land coupled systems in the Hanjiang River Basin (HJRB), the primary objective is to provide valuable insights that can inform strategic spatial management decisions, aligning with the ambitious objectives outlined in COP 27. Specifically, this study utilized the PLUS model, InVEST model, and redundancy analysis to comprehensively analyze the interplay between ecosystem services and land-use changes, with a specific focus on water, carbon, and land dynamics. The results showed that regardless of the simulated scenarios, there was a consistent pattern observed in the changes of land use types within the HJRB, with a decrease in farmland and an increase in forest. However, the water area showed an increasing trend in all scenarios, especially in the ecological land protection (ELP) and sustainable development scenarios. Furthermore, the ELP scenario effectively suppressed the expansion of building land and the erosion of ecological land. Ecosystem services under different scenarios showed similar spatial distribution patterns but presented varying degrees of change related to the impact of future land use and urban development on ecosystem services. The water yield (WY), carbon storage, and soil conservation in the upstream areas increased to varying degrees, while those in the downstream areas decreased. In conclusion, precipitation, land use/land cover change, DEM (Digital Elevation Model), and NDVI (Normalized Difference Vegetation Index) were the main driving factors affecting ecosystem services, with precipitation having the most significant and enduring impact on WY. This study supports the adoption of targeted spatial management measures to promote sustainable development and enhance human well-being.

Groundwater Contamination by Heavy Metals in Malaysia: Sources, Transport, and Remediation Strategies

Groundwater contamination by heavy metals is a pressing environmental concern, particularly in regions highly dependent on groundwater as a freshwater source. While Malaysia primarily relies on river water, certain states and islands depend on groundwater for their supply. Research on heavy metal contamination in Malaysia’s groundwater remains limited, making it crucial to study the distribution and mobility of contaminants to develop appropriate remediation strategies. In addition to natural sources, anthropogenic activities such as landfills, mining, and the use of fertilizers contribute significantly to heavy metal pollution in groundwater. Factors like rainfall, fluctuating groundwater levels, and low soil pH can exacerbate heavy metal leaching into aquifers. Various models and techniques, including 2D resistivity imaging and MODFLOW, are used to assess groundwater flow and contaminant transport. These models suggest that contaminant concentrations decrease with increased depth and radial distance from pollution sources such as landfills and mining areas. The health risks associated with heavy metal exposure through groundwater consumption are significant, necessitating effective remediation strategies. Phytoremediation is an economical solution for groundwater containing low concentrations of heavy metals, while permeable reactive barriers may be suitable for more complex cases, pending detailed site investigation. This review aims to examine the current state of knowledge on heavy metal contamination in Malaysia’s groundwater, focusing on sources, distribution patterns, and movement of pollutants. It also seeks to evaluate existing remediation methods, including phytoremediation and permeable reactive barriers, while identifying gaps in research, particularly concerning risk assessments and heavy metal speciation.

Unveiling heavy metal(loid) contamination and migration at an abandoned smelting site: Integrated geophysical and hydrological analyse

The heavy metal contamination at abandoned smelting sites is receiving increasing attention. This study focuses on an abandoned lead–zinc smelting site and uses several methods (such as soil sampling, geophysical exploration, and groundwater monitoring) to systematically investigate the contamination characteristics, distribution patterns, and migration mechanisms of heavy metal(loid) in soil and groundwater. A geological structure model of the study area was established through drilling data and geophysical techniques (Ground penetrating radar (GPR) and Electrical resistivity tomography (ERT)), revealing the relationships among soil resistivity, electromagnetic wave reflection characteristics, and geological structure. This study revealed that heavy metal contamination in soil was concentrated mainly northwest of the site and was closely related to historical smelting activities. The presence of heavy metal(loid)s in groundwater had a complex correlation with soil physicochemical properties and environmental elements, and its distribution was influenced by both hydrogeological conditions and soil properties. This study also investigated the effects of the soil water content (SWC) and soil hydraulic conductivity (Ks) on heavy metal(loid)s migration and reported that high SWC and Ks contribute to the dissolution and migration of heavy metals. In addition, a 3D visualization model of heavy metal contamination plumes was established via Voxler software. This model intuitively demonstrated the migration and diffusion of heavy metal(loid)s in the underground environment, offering a novel perspective on their subsurface behavior. The research results provide important information for understanding the migration of heavy metal(loid)s in soil-groundwater systems.

Exploring the medicinal potential of Dendrobium: Uncovering the spatial distribution of flavonoids and alkaloids in 15 species of Dendrobium using MALDI-MSI

Dendrobium, the second largest genus in the Orchidaceae family, has been regarded as a valuable medicinal plant throughout Chinese history. Secondary metabolites present in the stem of Dendrobium, including alkaloids and flavonoids, confer significant pharmacological effects such as anti-inflammatory, antibacterial, immunomodulatory, antitumor, and antioxidant properties. To our knowledge, this study is the first to apply matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) technology to comprehensively identify the spatial distribution of secondary metabolites, particularly flavonoids and alkaloids, in the mature stems of 15 common Dendrobium species. By analyzing the matching scores and relative concentrations of compounds, 20 flavonoids and 19 alkaloids with high identification credibility were identified, along with 4 sesquiterpenoid compounds. Their spatial distributions and compositions were analyzed, and the results revealed that despite the similar structural basis of the stems in the 15 Dendrobium species, significant differences existed in the distribution of secondary metabolites among different species. Flavonoids and alkaloids with different medicinal effects exhibited certain specific distribution patterns; for instance, flavonoids with antioxidant effects were mostly concentrated in the outer circle of thin-walled cells of Dendrobium stems, whereas those with antitumor effects were found in higher concentrations in the central areas of some Dendrobium species than in the periphery. Alkaloids with antitumor properties typically exhibited a higher concentration in peripheral thin-walled cells than in central regions. Furthermore, statistical analysis was conducted on the content of secondary metabolites with different effects among the 15 Dendrobium species to identify species with greater medicinal potential in terms of antioxidant and antitumor effects. The findings of this study not only enhance our understanding of the distribution patterns of flavonoids and alkaloids within Dendrobium stems but also offer valuable insights for the medicinal development and quality assessment of Dendrobium.

Peculiarities of the Species Composition, Abundance and Biotope Distribution of Mollusks Fam. Sphaeriidae in Rivers with a Many Lakes in the Catchment Area (by the Example of Water Courses of the Onega Lake Basin)

Using the example of the rivers of the Onega Lake basin, the species composition of mollusks of the Sphaeriidae family, their abundance, biomass, and contribution to benthic communities in rivers with many lakes in the catchment areas were analyzed. Patterns of spatial distribution of species across biotopes and gradients of environmental variables were traced. 26 species of mollusks of this family were identified, among them European-Siberian species predominate. Most of the species of mollusks of the family Sphaeriidae found by us have wide ecological ranges and are found in water bodies of various types. It was found that the contribution of Sphaeriidae to the species richness and functioning of aquatic communities in rivers in the conditions of branched lake-river systems (Lake Onega basin) exceeds the values usual for rivers with a small number of lakes in the catchment area. Using the ANOSIM and PERMANOVA methods, it was proved that the species composition of rocky rapids and riffles, sandy rifts and soft bottom soils is different. Using the IndVal test, seven species were shown to have a statistically significant association with one of these biotopes, and four of them, with rocky bottoms of river rapids and riffles. Using the NMDS method, it was shown that the greatest changes in the species composition of representatives of Sphaeriidae are observed when environmental conditions change from small streams with slow current and brown water to large rivers with fast current and clear water.

Variability of PAH Patterns in Upper Forest Soil (Sub)horizons—A Case Study From South‐Central Poland

ABSTRACTPolycyclic aromatic hydrocarbons (PAHs) are a class of contaminants characterized by their persistent and toxic nature. This study examines the variability in PAH distribution patterns in the upper layers of forest soils, focusing on the influence of different characteristics of individual soil (sub)horizons. A total of 130 samples were collected from five forest areas in south‐central Poland and analyzed for the 16 priority PAHs. Samples were taken from the organic fermentative‐humic (Ofh), humic (A), and humic‐eluvial (AE) (sub)horizons. The highest mean concentrations of total PAHs were found in the subhorizon‐Ofh (Ofh—1547 μg kg−1, A—1103 μg kg−1, AE—109 μg kg−1). The PAH content was significantly correlated with SOM content and pH, but this correlation was only significant in the horizon‐A. The percentage contributions of 3‐, 4‐, 5‐, and 6‐ring compounds to the total PAHs varied among the investigated soil (sub)horizons. The subhorizon‐Ofh had the highest percentage contribution of 6‐ring PAHs, 4‐ and 5‐ring PAHs were most prevalent in the horizon‐A, while 3‐ring compounds in the horizon‐AE. The variability in PAH patterns was also reflected in individual PAH ratios (BaA/BaA+Chr, IcdP/IcdP+BghiP), confirming the different behavior of 4‐, 5‐, and 6‐ring compounds in these (sub)horizons. This suggests that the retention of PAHs in the investigated (sub)horizons is influenced by several factors, including pH, degree of SOM decomposition, and mineral fraction, each to a different extent. Our findings reveal significant knowledge gaps regarding the behavior and accumulation of PAHs in soil (sub)horizons, underscoring the need for further research.