Efficient electrocardiogram generation based on cardiac electric vector simulation model.

This study introduces a novel Cardiac Electric Vector Simulation Model (CEVSM) to address the computational inefficiencies and low fidelity of traditional electrophysiological models in generating electrocardiograms (ECGs). Our approach leverages CEVSM to efficiently produce reliable ECG samples, facilitating data augmentation essential for the computer-aided diagnosis of myocardial infarction (MI). Significantly, experimental results show that our model dramatically reduces computation time compared to conventional models, with the self-adapting regression transformation matrix method (SRTM) providing clear advantages. SRTM not only achieves high fidelity in ECG simulations but also ensures exceptional consistency with the gold standard method, greatly enhancing MI localization accuracy by data augmentation. These advancements highlight the potential of our model to generate dependable ECG training samples, making it highly suitable for data augmentation and significantly advancing the development and validation of intelligent MI diagnostic systems. Furthermore, this study demonstrates the feasibility of applying life system simulations in the training of medical big models.

Characteristics and distribution of phosphorus in surface sediments of a shallow lake.

Phosphorus (P) in sediments plays an important role in shallow lake ecosystems and has a major effect on the lake environment. The mobility and bioavailability of P primarily depend on the contents of different P forms, which in turn depend on the sedimentary environment. Here, sediment samples from Baiyangdian (BYD) lake were collected and measured by the Standards, Measurements, and Testing procedure and Phosphorus-31 nuclear magnetic resonance spectroscopy (31P NMR) to characterize different P forms and their relationships with sediment physicochemical properties. The P content in the sediments varied in different areas and had characteristics indicative of exogenous river input. Inorganic P (334-916 mg/kg) was the dominant form of P. The 31P NMR results demonstrated that orthophosphate monoesters (16-110 mg/kg), which may be a source of P when redox conditions change, was the dominant form of organic P (20-305 mg/kg). The distribution of P forms in each region varied greatly because of the effects of anthropogenic activities, and the regions affected by exogenous river input had a higher content of P and a higher risk of P release. Principal component analysis indicated that P bound to Fe, Al, and Mn oxides and hydroxides (NaOH-P) and organic P were mainly derived from industrial and agricultural pollution, respectively. Redundancy analysis indicated that increases in pH lead to the release of NaOH-P. Organic matter plays an important role in the organic P biogeochemical cycle, as it acts as a sink and source of organic P.

Comprehensive analysis of the migration and transformation of nutrients between sediment and overlying water in complex habitat systems.

Under the influence of environmental change, disturbance and other external conditions, sediments release internal nutrients to the overlying water and become a contamination source in the lake. Complex habitat systems provide a unique opportunity for determining the influences of environmental changes in lakes. In this study, Baiyangdian Lake (BYDL) was divided into different habitat systems (connected water areas, river courses, reed fields, lotus ponds, fishponds, farmland, and thorps) based on the influence of natural and artificial activities. The physical and chemical properties of overlying water and sediment in different habitat systems were investigated. In addition, statistical analytical methods were used to analyze the relationship between sediment characteristics and overlying water parameters in different habitat systems. The results showed that nitrogen and phosphorus in the overlying water could accumulate in the sediments, while disturbance was one of the main factors affecting the release of nutrients from sediments. Disturbance promoted the suspension of sediments and increased the oxygen content, thereby facilitating the internal release of nutrients. However, there were also some differences in the process of internal release of nutrients between the habitat systems. Nitrogen in the overlying water was closely related to the source of organic matter (r > 0.950), especially in the ponds (including lotus ponds, reed fields, and fishponds), and phosphorus was mainly influenced by turbidity (r > 0.870). In the river course (p = 0.198, n = 26), the disturbance and increase in pH promoted the internal release of nutrients from the sediments (contributions of 35.2 % and 25.1 %, respectively). In the ponds, the aquatic macrophytes reduced the release of nitrogen and phosphorus in sediments. Overall, this study provides more information on the migration and transformation of nutrients between sediment and overlying water in lakes with multiple habitats.

Synergistic effect of novel Co-modified micro/nano geopolymers in a photo-PDS system.

Persulfate activation is an efficient advanced oxidation process for water treatment. However, many catalyst materials make their preparation methods and raw materials very complicated and expensive while pursuing high-efficiency catalytic effects. In this research, a novel Co-modified micro/nano geopolymer (Co-MNG) material was prepared from solid waste using a mechanochemical method. The whole preparation process of Co-MNG is simple and time-saving, and most of its raw materials are solid waste. In addition, it has few adverse effects on the environment during preparation and use and has a good effect on PDS activation. Under dark conditions, 1 mg L-1 of unloaded Co metal MNG material could degrade 20 mg L-1 Rhodamine B solution by 79% in 60 min with 15 mM PDS, but the application of visible light could not enhance its effect. However, after adding 4 wt% of different Co-containing compounds, the prepared Co-MNG materials could improve their degradation effect under the same conditions, and it is more obvious under the condition of applying visible light. Among them, MNG-Co(NO3)2 could completely degrade RhB within 40 min under the application of visible light. ESR (electron spin resonance) tests showed that the MNG-Co(NO3)2 material could generate a variety of active radicals in a photo-PDS system, such as h+, ·OH, ·O2- and SO4-. Mechanistic research experiments showed that both visible light and Co-MNG materials can activate PDS to a certain extent, but when both exist at the same time, the material could effectively couple visible light and Co activation of PDS in a photo-PDS activation system to achieve synergistic degradation of pollutants in water.

Facile synthesis of waste-based CdS-loaded hierarchically porous geopolymer for adsorption-photocatalysis of organic contamination and its environmental risks.

In order to obtain an adsorbent-photocatalyst with low-cost, strong stability and great reusability/recyclability, a waste-based and CdS-loaded hierarchically porous geopolymer (HPG) was prepared by facile synthesis. The adsorption-photocatalysis ability, reusability, and stability of HPG under different conditions were determined. Results indicated that HPG showed better adsorption-photocatalysis performance for organic dyes under alkaline environment, and it remained a high adsorption-photocatalysis efficiency after used for five times. Furthermore, HPG was stable in different environment conditions (strong acidic, acid raining, neutral, high salinity, and high alkali environment). The mass loss of HPG were around 3.22-6.68% (7 days extraction), and the immobilization rates of Cd2+ in neutral, high salinity, and high alkali environments were higher than 99.99%. Under visible light irradiation, HPG effectively photo-degraded the organic substances in overlying water of polluted sediments. After 330 min irradiation, the concentrations of COD and TOC were decreased from 47.52 mg/L and 20.9 mg/L to 16.58 mg/L and 11.19 mg/L, respectively. The humic-like and fulvic-like substances were transformed to protein-like substances under photo-degradation effect. This study confirmed that HPG possesses advantages in cost, chemical stability, and reusability, and it has a great potential to be used as in-situ remediation environmental functional material for organic contaminants in lake.

Solidification/stabilization of landfill leachate concentrate contaminants using solid alkali-activated geopolymers with a high liquid solid ratio and fixing rate.

Landfill leachate concentrate (LLC) is a highly toxic wastewater that contains many refractory contaminants. One of the technical and economic treatment methods is solidification/stabilization (S/S), where the contaminants of LLC can be sealed in one step to achieve zero wastewater discharge. This study presents the S/S of LLC contaminants using solid alkali-activated geopolymers prepared from blast furnace slag (BFS) and powdery sodium silicate. The stability of the formed geopolymer was studied through unconfined compressive strength (UCS) and leaching tests. The strongest UCS was obtained when the modulus of the activator was 1.16 with a high liquid/solid ratio of 0.64. BFS-based geopolymers presented excellent LLC S/S efficiency. The S/S rates of TOC, CODCr, NH3-N, Cl-, and SO42- were 81%, 89%, 97%, 97%, and 78%, respectively. The S/S rates of heavy metals, i.e., Cd and Pb, were all more than 99%. The results of microstructure characterization showed that the S/S mechanism of LLC pollutants was the dual effect of physical closure and chemical stability. Cl- and SO42- were respectively stabilized in the crystal lattice by Friedel's salt and calcium sulfate, respectively, while organic matter and NH3-N were physically encapsulated in the dense structure of the geopolymer. Overall, BFS based geopolymers demonstrated high treatment capacity and excellent S/S efficiency, and have a potential application prospects in LLC treatment.

Constructed wetland substrates: A review on development, function mechanisms, and application in contaminants removal.

Constructed wetlands (CWs) are economical, efficient, and sustainable wastewater treatment method. Substrates in CWs inextricably link with the other key components and significantly influence the performance and sustainability of CWs. Gradually, CWs have been applied to treat more complex contaminants from different fields, thus has brought forward new demand on substrates for enhancing the performance and sustainability of CWs. Various materials have been used as substrates in CWs, and their individual characteristics and application advantages have been extensively studied in recent years. Therefore, this review summarizes the development, function mechanisms (e.g., filtration, adsorption, electron supply, supporting plant growth and microbial reproduction), categories, and applications of substrates in CWs. The interaction mechanisms of substrates with contaminants/plants/microorganisms are comprehensively described, and the characteristics and advantages of different substrate categories (e.g., Natural mineral materials, chemical products, biomass materials, industrial and municipal by-products, modified functional materials, and novel materials) are critically evaluated. Meanwhile, the influences of substrate layer arrangement and synergism on contaminants removal are firstly systematically reviewed. Furthermore, further research about substrates (e.g., clogging, life cycle assessment/management, internal relationship between components) should be systematically carried out for improving efficiency and sustainability of CWs.

A review on the landfill leachate treatment technologies and application prospects of three-dimensional electrode technology.

With the expansion of urbanisation, the total amount of solid waste produced by urban residents has been increasing, and the problem of municipal solid waste disposal has also been aggravated. Landfill leachate treatment technologies could be divided into three categories: biological, physical and advanced oxidation treatment technology. Among them, advanced oxidation treatment technology has a good effect on the treatment of landfill leachate with little secondary pollution and has excellent application potential. Three-dimensional (3D) electrode technology, as a new type of advanced oxidation technology, could remove refractory pollutants in water and has attracted considerable attention. This article aims to (1) compare existing landfill leachate treatment technologies, (2) summarise 3D electrode technology application scenarios, (3) discuss the advantages of 3D electrode technology in landfill leachate treatment and (4) look ahead the future directions of 3D electrode technology in landfill leachate treatment. We hope that this article will be helpful to researchers who are interested in the field of landfill leachate treatment.

Enrichment differences and source apportionment of nutrients, stable isotopes, and trace metal elements in sediments of complex and fragmented wetland systems.

Anthropogenic activities significantly influence the lake environment and are reflected by the element contents in sediments/soils. The lake fragmentation provides a unique opportunity for comparing the influences of natural/anthropogenic activities of different wetlands systems. In this study, a complex and fragmented lake was investigated, and sediment/soil samples were collected from different systems. The nutrient contents (C, N, and P), stable isotopic compositions (δ13C and δ15N), and trace metal contents (As, Cd, Cr, Cu, Ni, Pb, and Zn) in the sediments/soils were measured to determine the natural and anthropogenic influences and pollution sources. Lake fragmentation was caused by insufficient water input and long-term agricultural and aquacultural activities of local residents. Due to the effect of anthropogenic activities, the enrichment conditions of various elements differed significantly for different wetland systems. Industrial, agricultural, and biological sources significantly influenced the element enrichment in different systems. The results demonstrated that the anthropogenic activities significantly influenced the sediments/soils in wetland systems, and the lake fragmentation reduced the diffusion of the contaminants. These results provide accurate reference information for pollution control, lake management, and ecological restoration.

Photoresponsive molecularly imprinted polymers based on 4-[(4-methacryloyloxy)phenylazo] benzenesulfonic acid for the determination of sulfamethazine.

Core-shell structured photoresponsive molecularly imprinted polymers were developed for the determination of sulfamethazine in milk samples. The photoresponsive imprinted polymers were prepared with polymethyl methacrylate containing a mass of ester groups as core, sulfamethazine as template molecules, self-synthesized water-soluble 4-[(4-methacryloyloxy)phenylazo] benzenesulfonic acid as a photoresponsive monomer, and ethylene dimethacrylate as cross-linker. Interestingly, the imprinted polymer can specifically adsorb sulfamethazine under dark and 440 nm irradiation, and release it at 365 nm. A series of adsorption experiments showed that the maximum adsorption capacity reached 12.5 mg⋅g-1 , and the adsorption equilibrium was achieved within 80 min. Moreover, the imprinted polymers display excellent reusability, with almost no performance loss after four times photo-controlled adsorption-release cycles, and the imprinted polymers have excellent selectively for sulfamethazine (imprinting factor  = 3.01). In the end, the imprinted polymers realized effective separation and enrichment of sulfamethazine in milk, with a recovery rate of over 97.5%. The material can be used as a solid-phase extractant in the process of enrichment and separation for the quantitative detection of sulfamethazine in milk samples.

Synthesis and characterization of a novel magnetic calcium-rich nanocomposite and its remediation behaviour for As(III) and Pb(II) co-contamination in aqueous systems.

Herein, a novel magnetic calcium-rich biochar (MCRB), prepared by loading Fe3O4 nanoparticles (Fe3O4 NPs) on crab shell-derived biochar, was studied for remediation of arsenic and lead co-contamination. Characteristics of the MCRB demonstrated that Fe3O4 NPs adhered on the biochar matrix uniformly. Batch experiments on the effects of pH, contact time and initial concentrations revealed that for both metals, removal by the MCRB was pH-dependent with an optimal pH of 6, and that the MCRB had a strong ability for removing arsenic and lead with maximum removal capacities of 15.8 and 62.4 mg g-1, respectively. The mechanisms of the simultaneous removal of arsenic and lead involved both competitive and synergistic effects. The As(III) addition enhanced Pb(II) removal by 5.4-18.8%, while the presence of Pb(II) suppressed As(III) removal by 5.8-17.8%. Competitive complexation of the two metals with biochar was responsible for the suppression, while the enhancement was due mainly to the formation of the Pb(II)-As(III)-FeO ternary surface complex with As(III) as the bridging molecule. These new insights can further our understanding of the application of MCRB as a potential material for use in the treatment of arsenic and lead co-contamination.

Immobilization efficiency and mechanism of metal cations (Cd2+, Pb2+ and Zn2+) and anions (AsO43- and Cr2O72-) in wastes-based geopolymer.

In this study, a composite geopolymer based on solid wastes (drinking water treatment residue (DWTR) and granulated blast furnace slag (GBFS)) were used in immobilization of heavy metals cations (Cd2+, Pb2+ and Zn2+) and anions (AsO43- and Cr2O72-). For evaluating the immobilization effect for heavy metals, the mechanical strength and leaching properties of geopolymers were investigated. Meanwhile, different characterization methods were used to research the immobilization mechanisms. The results indicated that the mechanical strength of geopolymers containing heavy metals was effectively improved by 37.11% with addition of DWTR. The stability of metals in geopolymer were increased and the release risk was decreased under the effect of DWTR. Characterization results verified the uniform distribution of heavy metals in geopolymer, and the adding of Pb2+, AsO43- and Cr2O72- caused the formation of crystalline phases. After the adding of heavy metals, the chemical environment change of Al 2p is more significant than Si 2p. Based on 29Si and 27Al MAS-NMR results, the different metals show various influences on the silicon and aluminum species in geopolymer matrix, and the strength of polymerized structure is mainly based on the Q4(mAl).

Distribution, ecological risk and source identification of heavy metals in sediments from the Baiyangdian Lake, Northern China.

Baiyangdian Lake (BYDL) is the largest plant-dominated freshwater wetland in the North China Plain. It plays an important role in supporting the construction of Xiongan New Area. Heavy metals contents (As, Cd, Cu, Cr, Ni, Pb, and Zn) in the sediments from BYDL are investigated to determine their spatial distribution and potential ecological risk in this study. Then the relationship and sources of contaminants were analyzed using a multivariate visual statistical analysis. The risk assessment results reveal that the surface sediments of BYDL are moderately to highly polluted by heavy metals, and the primary contaminants are Cd, Pb, and Zn. The spatial distribution of high potential risk regions mainly concentrate in the stream corridor between the east and west of the lake, and the distribution of high potential risk level of Cd, Pb, and Zn occur in a similar region. Additionally, exogenetic heavy metals are accumulated in the sediment cores within a depth of 16 cm, and their contents and risk decreased sharply with the increasing of depth. Furthermore, the results of statistical analysis implied that the Cd, Pb, and Zn in sediments are derived from industrial sources, the As and Cr from the geological process and the nutrients are from the nonpoint agricultural pollution. Overall, this study gives more information about the ecological risk distribution and pollution sources of BYDL, which is essential for the strategic design of future pollution control and environmental remediation.

Geopolymers produced from drinking water treatment residue and bottom ash for the immobilization of heavy metals.

Drinking water treatment residue (DWTR) and municipal waste incineration bottom ash (BA) have been traditionally considered as solid waste. With the development of urbanization, their subsequent treatment and resource regeneration need to be further researched. In this work, a composite geopolymer with BA and DWTR was successfully synthesized and applied in the immobilization of Cd, Pb and Zn. The analysis of the geopolymers with different ratios of BA and DWTR, curing times and heavy metals was performed through chemical analysis, SEM, FTIR, XRD, XPS, ICP-AES and compressive strength tests. The results show that the geopolymer samples based on BA and DWTR (BWG) presented higher compressive strength than the samples with single BA material. The sample with 20% DWTR and 80% BA (BWG20) possesses the highest compressive strength (24.10 MPa) among the materials ratios. Furthermore, the microstructure and characterization results indicate that the geopolymer matrix was successfully formed in BWG and was significantly changed by the ratio, curing time and addition of heavy metals. The immobilization efficiency for different categories and dosages of heavy metals by BWG20 were all higher than 99.43%. Moreover, the XPS results demonstrate that the heavy metals were immobilized in geopolymer mainly by divalent state forms.

Fraction spatial distributions and ecological risk assessment of heavy metals in the sediments of Baiyangdian Lake.

Baiyangdian Lake has been the ecological foundation of the Xiongan New Area, a newly developing economic zone in northern China since 2017, meaning that it is increasingly significant to recognize the contamination of the lake. In this work, the spatial distribution and ecological risk of heavy metals in the lake sediments were examined based on field investigation, multivariate statistical analyses and X-ray diffraction techniques (XRD). The results showed that the heavy metals in sediments pose moderate to high risks in most of the sample sites. The heavily contaminated sites presented more unstable chemical (exchangeable and reducible) fractions, and the ecological risk is highly sensitive to the exchangeable fraction in highly contaminative sites. The results of statistical analyses demonstrated that metal fractions were significantly correlated with physicochemical properties, and TP, TN and TOC exhibited a strong correlation with the exchangeable fraction of As, Cd, Pb and Zn. In contrast, Fe and Mn were weakly correlated with the fractions, which due to the high proportion of the nutrient elements in the sediment. Furthermore, the results from the XRD patterns demonstrated that the mineralogy phases of the various heavy metals contributed to the different chemical fractions. Those results demonstrated that further research on metal fraction distribution and influencing factors in the sediment should be implemented to ascertain the degree of toxicity to carry out effective strategies to remediate the lake sediment.

Bibliographic and visualized analysis of geopolymer research and its application in heavy metal immobilization: A review.

Geopolymer (GP) is a novel aluminosilicate inorganic polymer, and it possesses excellent characteristics in application of various fields, and its advantages have attracted worldwide attention. Based on the Citespace software, the bibliometric analysis combined with the visualization analysis on GP was summarized on the publications that extracted from Web of Science (WOS) from 1990 to 2017. The analysis results demonstrate that the research on GP develops rapidly in the last years, and the GP have already possessed a degree of application value in several engineering fields. This research shows a multidisciplinary amalgamation tendency in contents and methods. Additionally, the main application in pollution treatment of GP is heavy metal immobilization. The immobilization effects of GP for heavy metal are mainly depended on physical encapsulation, adsorption effect, chemical bonding, substitution for Al3+ and other effects. And these effects are simultaneous action on heavy metal immobilization under different conditions. Furthermore, the majority of GP are based on the fly ash and metakaolin, and the most frequently used leaching method is the Toxicity Characteristic Leaching Procedure (TCLP). Moreover, there are also several problems need to be solved before GP can be widely applied in heavy metal treatment. Overall, GP have possessed a great potential research and application value in the present stage, especially in the aspect of heavy metal immobilization.