Search Results (147)

Oxalic acid is extensively used in industrial chemical processes, purification systems, hydrometallurgical operations, and advanced oxidation environments where rapid and environmentally sustainable analytical methodologies are increasingly required for process monitoring and quality control. In this study, a micro-Raman spectroscopy methodology was developed for the direct quantification of oxalic acid in aqueous systems at moderate-to-high concentrations (0.079–0.793 M). The analytical strategy was based on the integrated Raman response of the carbonyl stretching region (1700–1750 cm⁻¹), selected due to its strong concentration-dependent behavior, spectral definition, and reduced interference from the aqueous matrix. The proposed methodology demonstrated excellent analytical performance, including high linearity (R² > 0.998), satisfactory precision, and reliable concentration-dependent reproducibility throughout the evaluated concentration range. To evaluate operational robustness, matrix-matched standards incorporating temperature variation (25–40 °C), turbidity (0–57 mg/L), dissolved Ca²⁺ (0–58 mg/L), and dissolved Fe³⁺ (0–7 mg/L) were prepared to simulate chemically perturbed industrial environments. Principal Component Analysis (PCA) demonstrated that the carbonyl vibrational region retained organized concentration-dependent spectral behavior despite operational perturbations. Partial Least Squares (PLS) regression models developed under these matrix-informed conditions preserved strong predictive capability (R² ≈ 0.997), while preliminary prediction of process-related samples yielded excellent agreement between predicted and reference concentrations (R² = 0.990). Although operational perturbations produced substantial attenuation of Raman intensity, particularly at lower concentration levels, the carbonyl Raman band remained spectrally detectable and analytically interpretable throughout all evaluated conditions. Electronic-structure analysis using Natural Bond Orbital (NBO) and Atoms-in-Molecules (AIM) methodologies demonstrated that the strong analytical behavior of the ν(C=O) vibrational mode is associated with enhanced electron-density localization, covalent stabilization, and favorable polarizability characteristics of the carbonyl bond. The combined experimental, chemometric, and computational results demonstrate the feasibility of matrix-informed micro-Raman spectroscopy as a rapid, reagent-free, and operationally robust methodology for oxalic acid monitoring in chemically perturbed aqueous industrial systems. Full article

Organic matter production, recycling, and burial processes temporally fluctuate across the Clarion-Clipperton Zone (CCZ) in the Eastern Tropical Pacific. Between 2019 and 2022, we conducted pelagic and benthic surveys in Nauru Ocean Research Inc. contract area D (NORI-D) in the southeast CCZ to establish environmental baseline conditions. Here, we synthetise the natural ranges of variability in physicochemical and biogeochemical processes in NORI-D across multiple surveys and years. We present interannual water column physicochemical characteristics from five metocean and pelagic campaigns, annual satellite-derived net primary productivity and export production, time-integrated sediment trap annual particulate organic carbon flux, and seafloor biogeochemical and sediment physical characteristics from three benthic campaigns. Temperature and salinity seasonally varied at the sea surface. Strong thermohaline and oxygen stratification developed over 0–100 m. Mean net primary productivity, export production, and seafloor particulate organic carbon flux amounted to 634.1, 15.7, and 2.1 mg C m⁻² d⁻¹, respectively. These rates fluctuated nearly four-fold seasonally and interannually. An oxygen minimum zone (100–700 m) dampened organic carbon flux attenuation (b = −0.538) to the abyss. Abyssal seafloor organic matter dynamics showed more homogenous conditions in 2020–2021 (TOC = 0.57 ± 0.05%) than in 2022 (TOC = 0.42 ± 0.19%). Bioturbation rate and mixed-layer depth decreased from 2020 to 2022, while oxygen consumption increased at 0–1 cm bsf. Lipid consumption and compositional alteration in 2022 surpassed 2020–2021. Our findings provide critical baseline data to inform environmental impact assessments and monitoring programmes for deep-sea mining of polymetallic nodules in NORI-D. Full article

Land subsidence is an important challenge faced by coastal cities under rapid urban development. This study focuses on the Haikou–Laocheng area and conducts time-series monitoring of land subsidence using PS-InSAR and SBAS-InSAR based on 42 Sentinel-1 SAR scenes acquired from April 2023 to April 2025, thereby deriving the spatial distribution of cumulative subsidence rates and the evolution patterns of multi-temporal cumulative subsidence. Because only ascending-orbit Sentinel-1 data were used, the reported deformation values are vertical-projected estimates converted from line-of-sight (LOS) displacement under the assumption that horizontal motion is negligible. The reliability of the monitoring results is evaluated through cross-validation between the two methods, assessing their inter-method consistency. The results indicate that the study area is dominated by slight subsidence, with vertical-projected subsidence rates mainly ranging from −6 to 3.7 mm/y, while a few uplift points are locally observed, forming an overall “stable with localized anomalies” deformation pattern. PS-InSAR and SBAS-InSAR show good consistency in overall trends, and both identify a pronounced subsidence bowl in the southwestern part of the study area, where the peak vertical-projected subsidence rates reach −25.1 mm/y and −35.1 mm/y, respectively, with outward banded attenuation. The results suggest that land subsidence in the study area is influenced by both natural factors and human activities. Specifically, rainfall shows a non-synchronous, stage-wise modulation relationship with subsidence evolution, and most high-subsidence zones are distributed in impervious surfaces such as built-up land and transportation corridors, or in low-elevation areas such as farmland. In terms of geological factors, thick, highly compressible soft soils are the primary geological control on the continued development of subsidence. These findings can provide scientific references for the prevention and control of abnormal subsidence and for urban planning and development in the Haikou–Laocheng area. The strengthened discussion clarifies the research gap, planning significance, and limitations of applying dual time-series InSAR in a data-scarce tropical coastal soft-soil setting. Full article

Petroleum contamination of soils remains a significant environmental problem in boreal regions, where low temperatures constrain natural attenuation processes and complicate bioremediation. Nitrogen biostimulation is widely used to enhance petroleum hydrocarbon degradation; however, the combined effects of temperature regime, nitrogen form, contamination level, and nitrogen dosage remain insufficiently resolved for sandy podzolic soils of northern regions. This study investigated nitrogen-assisted biostimulation of petroleum-contaminated sandy podzolic soil collected in the Khanty–Mansi Autonomous Okrug (Western Siberia, Russia) using a factorial experimental design. Soil samples were artificially contaminated with crude oil at concentrations of 25, 50, and 100 g kg⁻¹ and incubated under warm and cold temperature regimes. Two nitrogen sources, urea and ammonium nitrate, were applied at several dosages. Changes in residual petroleum hydrocarbon content were monitored together with the abundance of culturable microorganisms under the applied cultivation conditions at the intermediate contamination level on day 60. Nitrogen supplementation enhanced petroleum hydrocarbon removal relative to the untreated control, but the magnitude of the effect depended substantially on temperature, nitrogen form, and contamination level. Under the tested conditions, ammonium nitrate was generally associated with stronger hydrocarbon removal than urea, particularly at the intermediate contamination level (50 g kg⁻¹). The results indicate that the response to nitrogen biostimulation in sandy boreal soils is controlled by interacting experimental factors rather than by nitrogen addition alone. These findings improve the positioning of nutrient-assisted remediation in cold-region soils and provide a basis for future mechanistic and field-scale studies. Full article

Achieving a credible net-zero transition requires reliable corporate environmental information to support effective climate governance. When firms overstate environmental commitments without corresponding improvements in actual performance, regulatory signals become distorted, and decarbonization efforts are weakened. This study examines whether stringent command-and-control environmental regulation enhances the credibility of corporate climate commitments. Using the staggered implementation of China’s Air Pollution Prevention and Control Action Plan as a quasi-natural experiment, we construct a firm-level measure of corporate greenwashing that captures the divergence between environmental discourse and regulatory performance. Based on a multi-period difference-in-differences model, the results indicate that environmental regulation significantly reduces corporate greenwashing, with the probability of inconsistency between environmental claims and actual behavior declining by approximately 25 percent relative to the sample mean. Mechanism analysis shows that this effect operates through increased green technological innovation and heightened public environmental concern, which together strengthen substantive compliance and external monitoring. The moderating analysis shows heterogeneous responses across firms: board independence strengthens the policy’s inhibitory effect, while market share and institutional ownership attenuate it. Overall, the findings suggest that command-and-control regulation improves the credibility of disclosure and reinforces the informational foundations necessary for an effective net-zero transition. Full article

A 2-acre reedbed system, cultivated with Phragmites australis, was established and utilized to remediate groundwater polluted with chlorinated hydrocarbons at a former industrial site. The reedbed comprised a combination of horizontal and vertical systems over four parallel installations, with a treatment capacity of 305 m³/day. The mean inlet concentration for the four-line treatment was 112.4 mg/L, which was below the specified inlet concentration of 250 mg/L. From 2019 to 2024, the reedbed system effectively eliminated 1,2-Dichloroethane (1,2-DCA), with average removal rates of 97.7%, 98.8%, 98.5%, and 98.6% for Lines 1 to 4, respectively. The average outlet concentrations of 1,2-DCA were 0.70 mg/L, 0.40 mg/L, 0.42 mg/L, and 0.52 mg/L for Lines 1–4, respectively, resulting in an overall average of 0.51 mg/L. We performed the assessment of natural attenuation by first-order decay kinetics for five groundwater monitoring wells, showing values between 0.0012/year and 0.0036/year (shallow wells), 0.0003/year and 0.0021/year (middle wells), and 0.0003/year and 0.0009/year (deep wells). Here, shallow groundwater showed the highest kinetic rates compared to middle and deep groundwater wells. The results indicated that the reedbed system removed the bulk of contaminants through active biological processes involving plants and microbes, and that natural attenuation further degraded 1,2-DCA in the groundwater profiles. Based on data monitoring from 2019 to 2024, the reduction and degradation results showed good removal efficiency for the reedbed systems, combined with natural attenuation in the groundwater. Full article

Urban flooding represents an increasingly critical challenge in rapidly urbanizing cities, where high-density development and climate variability intensify hydrological vulnerability. This article presents an analytically focused case study of Shenzhen, a national Sponge City pilot, to examine not only whether nature-based interventions are associated with flood-resilience gains but also under what spatial, institutional, and governance conditions such gains emerge. The study adopts a qualitative mixed-methods case-study design based on secondary sources, integrating observed flood-event records, reported hydrological and water-quality indicators, model-based projections, and systematic policy analysis. Drawing on data from 2006–2020, the analysis explicitly distinguishes observed outcomes, reported performance indicators, and inferred effects, addressing a key methodological limitation in existing Sponge City assessments. Results indicate that, within designated pilot zones, Sponge City interventions are associated with reduced surface runoff, attenuated peak flows, and reported improvements in pollutant filtration, particularly where green infrastructure density and monitoring capacity are high. However, these performance patterns are spatially uneven and mediated by governance constraints, including institutional fragmentation and maintenance capacity. The principal contribution of the study lies in identifying governance–infrastructure mechanisms that condition Sponge City performance and scalability. By treating Shenzhen as a critical rather than representative case, the article offers analytically transferable insights into the effectiveness, durability, and limits of nature-based flood-management strategies in high-capacity urban contexts. Full article

Urban traffic noise poses escalating environmental challenges in rapidly urbanizing regions with high-density buildings, yet systematic investigations into its spatiotemporal characteristics remain relatively scarce. This study addresses this research gap via the synchronized on-site monitoring of traffic noise and traffic flow on a representative arterial road in Guangzhou, China. The analysis reveals that nighttime equivalent continuous A-weighted sound levels (L_Aeq) are 3.0–4.0 dB(A) higher than those during the congested daytime peak, a phenomenon primarily driven by higher vehicle speeds under nighttime free-flow traffic conditions. The spatial analysis uncovers complex three-dimensional noise propagation dynamics specific to urban street canyons. Vertical profiling demonstrates a counterintuitive pattern where noise levels do not attenuate with building height, and upper floors experience marginally higher noise exposure than the ground floor, which is attributed to the canyon effect, where multiple sound wave reflections offset the natural distance attenuation. A validated three-dimensional computational model was further employed to evaluate the efficacy of noise mitigation strategies, showing that an integrated intervention combining porous asphalt pavement and acoustic barriers achieves a maximum noise attenuation of 19.9 dB(A) at ground-level receptors. This significant reduction stems from a synergistic effect: porous asphalt reduces noise at the source on a global scale, while acoustic barriers provide localized shielding for the lower floors of adjacent buildings. This research concludes that effective traffic noise control in high-density urban areas requires three-dimensional, multi-faceted strategies addressing noise source characteristics, transmission pathways, and receptor vulnerabilities. Full article

Background/Objectives: African swine fever is currently the most devastating viral disease affecting domestic and wild suids, causing major economic losses and severe impacts on natural populations. Oral immunization could become an important tool to control the panzootic and support wild pig conservation. However, this requires safe and effective vaccines, baits accepted by target species, and vaccine reservoirs that reliably release the vaccine during bait intake while maintaining vaccine integrity. Methods: We evaluated different bait types and vaccine containers in four wild Suiformes species, including Eurasian wild boar. In the same wild boar, we assessed oral vaccination with the live attenuated vaccine candidate “ASFV-G-ΔI177L”. Environmental monitoring approaches were applied to detect potential virus shedding, and vaccine immunogenicity and dissemination were evaluated. Vaccine stability was tested in vitro in two container types under different temperature conditions. Results: Bait uptake and container performance varied between manufacturers and among species. Environmental samples were largely negative for vaccine virus genome under controlled laboratory conditions, with only a few positive cotton ropes (0.43% of all samples). After oral bait vaccination, 45% (9/20) of wild boar seroconverted, with a higher proportion in animals receiving the vaccine in the slightly less attractive bait (gelatine-based). Vaccine virus dissemination was limited to a small number of organs, including gastrohepatic and mandibular lymph nodes. Conclusions: Our findings demonstrate that wild pigs can be vaccinated orally with “ASFV-G-ΔI177L” while virus shedding appears minimal. Although the tested baits show potential for multiple target species, baits and containers require optimization. Environmental monitoring methods also need refinement for field application. Full article

Decentralized graywater treatment using nature-based systems represents a sustainable, low-energy alternative to centralized wastewater technologies, particularly in water-scarce regions. This study evaluates the performance of a rain-garden-based constructed wetland implemented at Zain Park in Jerash, Jordan, for on-site graywater treatment and potential non-potable reuse. The system consists of two filtration beds with multi-layer gravel–sand media planted with ornamental vegetation to promote physical filtration, adsorption, and biologically mediated transformations. Influent and effluent samples were monitored monthly from April 2024 to January 2025 and analyzed for biodegradable and oxidizable organic fractions (BOD₅ and COD), nutrients (TN, PO₄³⁻), suspended solids, turbidity, salinity indicators, and microbial parameters (E. coli and total coliform). Average removal efficiencies reached 98% for BOD and 96% for COD, while turbidity and TSS were reduced by more than 96%, indicating effective organic degradation and particulate retention. Nutrient removal was moderate, with 40% reduction in Total Nitrogen and 74% in nitrate, reflecting partial nitrification–denitrification and plant uptake. Microbial removal was variable, with an average reduction of 0.8 log₁₀ (64.7%) for E. coli and 1.1 log₁₀ (82.6%) for total coliforms, indicating that passive filtration alone may not ensure complete pathogen attenuation. Post-treatment disinfection and substrate enhancements (aeration and plant selection) can strengthen system efficiency and support sustainable graywater reuse in water-stressed regions, contributing directly to SDG 6 (Clean Water and Sanitation), SDG 11 (Sustainable Cities and Communities), and SDG 12 (Responsible Consumption and Production). These findings support the applicability of compact constructed wetland systems as decentralized wastewater treatment solutions in arid and semi-arid urban environments. Full article

This research investigates the dynamic response of three-dimensional concrete beams with coated aggregates subjected to transient wave propagation induced by piezoelectric actuators (PZT-lead zirconate titanate). The aim was to assess the effects of coated aggregates on concrete’s damping behavior and wave attenuation. The effect of various coating materials (epoxy and rubber) and replacement levels ranging from 5% to 25% by volume of the natural coarse aggregates on wave attenuation and energy dissipation were investigated through Finite Element Modeling (FEM) using Abaqus/CAE 6.14-1 software. Moreover, the effect of coating thickness is investigated for thicknesses ranging from 1.0 mm to 3.5 mm. The findings show that the replacement level, coating thickness, and coating material have a major effect on damping characteristics of concrete. It was also observed that rubber-coated aggregates with a 3.0 mm coating thickness (20% replacement level) exhibited an optimal damping ratio of 6.15%, representing a 29.5% increase, and offer enhanced energy dissipation, better damping performance, and the ability to alter wave travel paths, all of which could be advantageous for Structural Health Monitoring (SHM) applications. In line with this, the damping ratio of concrete beam models with epoxy- and rubber-coated aggregates, embedded with PZT material, was significantly higher (by approximately 1% to 18%) compared to that of the concrete model without PZT materials. Additionally, the findings showed that the concrete’s damping properties were greatly impacted by the interaction between PZT materials and coated aggregates. All things considered, the dynamic response and damping performance of concrete with coated-aggregate surface properties were successfully assessed using PZT-based simulations. Full article

Hydrocarbon-based rocket fuels, particularly kerosene grades T-1 and RG-1 used during launch vehicle operations, represent a persistent source of soil contamination in areas impacted by rocket stages. This study quantitatively evaluates the response and recovery dynamics of soil microbial communities in Calcisol (Loamic) soils from the U-25 impact area near the “Baikonur” Cosmodrome (Kazakhstan) under controlled kerosene contamination. Eleven soil samples were monitored over 90 days, including one uncontaminated control and ten samples exposed to increasing concentrations of T-1 or RG-1 (100–15,000 mg/kg). Microbial indicators included total microbial count, actinomycetes, microscopic fungi, and spore-forming bacteria, expressed as CFU/g (mean ± SD, n = 3). Acute exposure caused significant reductions in total microbial abundance (28–58%) and microscopic fungi (43–75%, p ≤ 0.05), indicating pronounced short-term toxicity. By Day 90, bacterial and actinomycete populations exhibited partial to complete recovery, with some treatments exceeding control values, suggesting metabolic adaptation and hydrocarbon utilization. In contrast, fungal populations remained consistently suppressed throughout the experiment, indicating prolonged ecological stress. No strict dose–response relationship was observed, highlighting the influence of soil physicochemical properties on microbial resilience and hydrocarbon bioavailability. These findings identify microscopic fungi as the most sensitive indicators of kerosene contamination, suggesting that indigenous bacterial and actinomycete communities play a key role in natural attenuation. The results provide quantitative thresholds relevant for environmental monitoring and support the development of microbiologically informed bioremediation strategies in areas impacted by rocket launches. Full article

Background/Objectives: Epidemiological and clinical studies have linked both hypothyroidism and hyperthyroidism to adverse cardiac outcomes, including heart failure and myocardial fibrosis. Triiodothyronine (T3), a biologically active thyroid hormone, is important for cardiovascular homeostasis. While the effects of physiological and non-physiological T3 levels on cardiomyocytes have been extensively investigated, the impact of hypothyroidism and hyperthyroidism on cardiac stromal cells (CSCs), which constitute the majority of the cells in the heart, remains understudied. Given CSCs’ essential role in extracellular matrix (ECM) remodeling and paracrine signaling, understanding their response to altered T3 states is necessary to fully elucidate the thyroid hormone-induced cardiac responses. Methods: Cardiac stromal cells were isolated from human atrial appendages and cultured under hypothyroid (0 nM T3), euthyroid (2.5 nM T3), and hyperthyroid (25 nM T3) conditions for 24 (short term) and 120 h (long term). The cells were harvested after 24 h of treatment using trypsin and automatically counted, and their ECM-related gene and growth factor expression levels were assessed using quantitative RT-PCR. Cardiac glucose uptake in hypothyroid, euthyroid, and hyperthyroid mice was monitored using [18F]-FDG PET/CT at acute (7 days) and chronic (42 days) time points. Results: Both hypo- and hyperthyroidism significantly increased the number of CSCs harvested after 24 h. There were acute alterations in the expression of the ECM-related genes COL1A1, COL3A1, TIMP3 (p < 0.05), and TIMP1 (p < 0.01). Similarly, growth factors such as PDGF-A (p < 0.001), TGF-b, and IGF1 (p < 0.05) were transiently upregulated under non-physiological T3 conditions, especially hypothyroidism. Most of these alterations were attenuated or reversed at the 120 h time point. In vivo PET imaging revealed significant increases in cardiac glucose uptake under acute hypothyroidism (p < 0.05) and decreases under acute hyperthyroidism (p < 0.05). However, these metabolic shifts normalized with chronic exposure, paralleling the transient nature of the gene expression changes observed in vitro. Conclusions: Non-physiological T3 concentrations induce proliferation and changes in ECM-related and growth factor gene expression in CSCs. Most of these changes are acute and return to normal levels after chronic exposure. These transient cellular responses correlate closely with the cardiac metabolic response patterns to acute and chronic hypothyroidism and hyperthyroidism. Full article

Rapid urbanization and persistent air pollution threaten the functional resilience of megacities in Southeast Asia, particularly Bangkok, where PM_2.5 concentrations consistently exceed World Health Organization (WHO) guidelines. To strengthen urban adaptive capacity, this study investigates the role of Nature-based Solutions (NbS), particularly urban green spaces, as resilience-oriented infrastructure for air quality management. Using data from 32 monitoring stations across the Bangkok Metropolitan Administration (BMA) and surrounding areas from 2021 to 2023, spatial and temporal trends in PM_2.5 concentrations were analyzed through geostatistical modeling and inferential statistics. Although all sites exceeded the WHO PM_2.5 guideline of 5 µg/m³, larger and more connected green spaces consistently exhibited better air-quality than the surrounding non-green urban mosaic. Areas with extensive vegetation, greater canopy cover, and more compact park geometries (lower perimeter-to-area ratios) demonstrated improved pollution attenuation capacity, while fragmented parks are more exposed to surrounding emissions. Integration of Local Climate Zone (LCZ) classification further indicated that compact high-rise zones and high-traffic corridors exhibited higher PM_2.5 levels due to reduced airflow and structural confinement. The study underscores the need to embed NbS within resilience-based urban planning to promote long-term environmental stability and public health recovery in rapidly urbanizing megacities like Bangkok. Full article

The present work aims to synthesize polyamide 1212 (PA 1212) via direct solid-state polymerization (DSSP), starting from its solid salt precursor. The DSSP of aliphatic polyamide salts has been found to proceed through melt intermediates, in harmony with the well-documented solid-melt transition (SMT) mechanism. However, PA 1212 salt is anticipated to deviate from this model due to its strongly hydrophobic nature. The reaction was initially investigated at the microscale in a thermo-gravimetric analysis (TGA) chamber and then scaled up to the laboratory scale. The influence of reactor design, reaction temperature, and residence time was examined. DSSP products were characterized in terms of molecular size and morphological properties. At the same time, a novel protocol was developed for qualitatively monitoring the progress of polymerization via Fourier Transform Infrared Spectroscopy-Attenuated Total Refraction (FTIR-ATR) analysis. Emphasis was given on the resulting morphology examined via Scanning Electron Microscopy (SEM imaging). Although DSSP has been found to proceed through a quasi-SMT, significant differences are observed compared to the classical mechanism established in the literature. This paper reveals that the limited surface softening or agglomeration phenomena encountered are mostly associated with the hydrophobic structure of the PA 1212 salt. Full article