Impacts of land use on phosphorus and identification of phosphate sources in groundwater and surface water of karst watersheds.

The thin soil layer with uneven distribution in karst areas facilitates the migration of phosphorus (P) to groundwater, threatening the safety of water sources seriously. To offer a scientific guidance for water pollution control and land use planning in karst areas, this study examined the relationships between land use and P in groundwater and surface water, and quantified the phosphate sources in Gaoping river basin, a small typical watershed in karst areas. Spatial distribution analysis revealed that the highest mean P concentrations in groundwater and surface water were in farmland and construction-farmland zones, respectively. Land use impact analysis showed that the concentration of P in groundwater was influenced positively by farmland but negatively by forest land. In contrast, the concentration of P in surface water was influenced positively by both farmland and construction land. The mixed end-element and Bayesian-based Stable Isotope Analysis in R (SIAR) model results showed that agricultural fertilizers were the main phosphate source for groundwater in farmland and forest-farmland zones, while urban sewage was the main source in the construction-farmland zone. For surface water, the main phosphate source was agricultural fertilizers in both farmland and construction-farmland zones. This study indicates that controlling P pollution in local water bodies should pay close attention to the management of land use related to human activities, including regulating sewage discharge from construction land and agricultural fertilizer usage.

Formate-Mediated Electroenzymatic Synthesis via Biological Cofactor NADH.

Synthetic biohybrid systems by coupling artificial system with nature's machinery may offer a disruptive solution to address the global energy crisis. We developed a versatile electroenzymatic pathway for the continuous synthesis of valuable chemicals, facilitated by formate-driven NADH regeneration. Utilizing a bismuth electrocatalyst, we achieved stable CO2 reduction to formate with approximately 90 % Faraday efficiency at a current density of 150 mA cm-2. The generated formate acts as a mediator to regenerate NADH, which is then coupled with immobilized redox enzymes-alcohol dehydrogenase (ADH), L-lactate dehydrogenase (LDH), and L-glutamate dehydrogenase (GDH)-to produce targeted chemicals at significant rates and exceptionally high turnover numbers (1.8×106 to 3.1×106). These achievements not only underscore the efficiency of the system but also its practical applicability in industrial settings. By leveraging in situ generated formate, this innovative approach demonstrates the potential of integrating electrocatalysis with enzymatic reactions for sustainable and efficient chemical production on a practical scale.

Ferroptosis: a new target for iron overload-induced hemophilic arthropathy synovitis.

Iron deposition is closely related to developing haemophilic arthropathy (HA). Studying the relationship between ferroptosis signal expression and iron overload in HA synovium facilitates understanding the pathogenesis of joint synovial hyperplasia in bloodborne arthritis and the development of new protective methods. The knee synovium was collected from HA and osteoarthritis (OA) patients, and pathological changes were analysed by HE and Prussian blue staining. Ferroptosis phenotypes were examined by immunohistochemistry and western blotting. Moreover, ferric ammonium citrate (FAC)-induced was used to construct an in vitro iron overload model to investigate the relationship between iron overload and ferroptosis in synovial fibroblasts (FLS). Furthermore, the factors influencing ferroptosis in FLS were explored. Iron deposition, cell proliferation, and vascular proliferation in the synovium of HA were more obvious. Ferroptosis in HA synovium appears to inhibit. FLS ferroptosis increased with iron accumulation, malondialdehyde (MDA) in cells, and glutathione (GSH) depletion. TNF-α plays a protective role in this process. Blocking the action of TNF-α and inducing ferroptosis significantly reduced synovial proliferation. TNF-α inhibitors combined with a ferroptosis inducer may be a new therapeutic method for HA synovitis.

Surface-enhanced Raman imaging through sprayed probes for the application in chemical visualization of methamphetamine within fingerprints.

For fingerprint-involved forensic investigations, cyanoacrylates and inorganic nanophosphors are mostly used for fingerprint visualization. However, methods to simultaneously report fingerprint images and the corresponding specific chemical information have yet to be realized. In this work, chemical visualization of the analytes in fingerprints is achieved through surface-enhanced Raman spectroscopy (SERS) measurements with the aid of spray-dispersed gold nanorods (AuNRs). The optimal coverage of AuNRs was studied by theoretical simulations and experimental operations. A rapid sampling of fingerprints with the chemical of interest was developed by tuning the spray parameters. In particular, the SERS imaging of methamphetamine in fingerprint latent was attempted by addressing the SERS spectral features of methamphetamine. This chemical visualization method reflects both the graphical and chemical characteristics of fingerprints in a single batch measurement, in which methamphetamine can be detected and mapped at the concentration of 10-5 M. The data processing approach was also modified by employing relevant logical judgments. The improved SERS images with sharpened patterns of fingerprints were obtained by involving the scored multi-peak judgments.

Ultrafast synthesis of laccase-copper phosphate hybrid nanoflowers for efficient degradation of tetracycline antibiotics.

The presence of antibiotics in the environment causes increasing attention due to their potential risks to ecosystems and public health. Laccases are versatile oxidases capable of degrading various organic contaminants including pharmaceuticals. However, the performance of bacterial laccases on tetracycline antibiotics (TCs) degradation is seldom investigated. In this work, a bacterial laccase from Bacillus amyloliquefaciens was immobilized as laccase-inorganic hybrid nanoflowers (Lac-hNFs) by a facile and rapid method. The immobilized laccase was employed to remove different TCs including tigecycline, which is a third-generation TC that its degradation by laccase has not been reported. Lac-hNFs were synthesized by sonication-mediated self-assembly of laccase and copper ions in 5 min at room temperature. About 95% of laccase could be encapsulated in the nanoflowers, and the obtained Lac-hNFs exhibited great enhancement in stability under harsh conditions. The immobilized laccase showed a half-life of 11.7 h at 60 °C, which was about 1.4-fold higher than that of the free enzyme. Meanwhile, Lac-hNFs retained 81% of the initial activity after incubation at 25 °C for 10 days. The laccase in combination with acetosyringone could efficiently decompose tetracycline, doxycycline, and tigecycline. More than 79% of the three TCs were transformed in 1 h. Compared with the free enzyme, Lac-hNFs demonstrated higher capacity in the removal of TCs. Furthermore, Lac-hNFs remained their high degradation capacity after five cycles of reuse. Bacterial growth inhibition test revealed that most of the toxicity of TCs was eliminated after Lac-hNFs treatment. The main transformation products were identified by LC-MS, and the possible degradation pathways were proposed. The interaction mechanism between laccase and TCs was also analyzed using molecular docking. This work provides an efficient way to remove toxic organic pollutants.

Recent Progress in Atmospheric Chemistry Research in China: Establishing a Theoretical Framework for the "Air Pollution Complex".

Atmospheric chemistry research has been growing rapidly in China in the last 25 years since the concept of the "air pollution complex" was first proposed by Professor Xiaoyan TANG in 1997. For papers published in 2021 on air pollution (only papers included in the Web of Science Core Collection database were considered), more than 24 000 papers were authored or co-authored by scientists working in China. In this paper, we review a limited number of representative and significant studies on atmospheric chemistry in China in the last few years, including studies on (1) sources and emission inventories, (2) atmospheric chemical processes, (3) interactions of air pollution with meteorology, weather and climate, (4) interactions between the biosphere and atmosphere, and (5) data assimilation. The intention was not to provide a complete review of all progress made in the last few years, but rather to serve as a starting point for learning more about atmospheric chemistry research in China. The advances reviewed in this paper have enabled a theoretical framework for the air pollution complex to be established, provided robust scientific support to highly successful air pollution control policies in China, and created great opportunities in education, training, and career development for many graduate students and young scientists. This paper further highlights that developing and low-income countries that are heavily affected by air pollution can benefit from these research advances, whilst at the same time acknowledging that many challenges and opportunities still remain in atmospheric chemistry research in China, to hopefully be addressed over the next few decades.

FGF23 and SOX9 expression in haemophilic cartilage: In vitro studies of the effects of iron.

INTRODUCTION: Clarifying the links between iron and FGF23, SOX9 expression in chondrocytes would be helpful for comprehending articular cartilage degradation pathogenesis in blood-induced arthritis and exploring new protective methods. AIM: The purpose of this study was to determine iron regulation of fibroblast growth factor 23 (FGF23) and SRY-box 9 (SOX9) in human chondrocytes, an area which is unexplored in blood-induced arthritis cartilage degradation pathogenesis. METHODS: Expression of FGF23, SOX9, MMP13 and collagen Ⅱ in articular cartilage of patients with osteoarthritis (OA) or haemophilic arthritis (HA) was determined by western blot (WB). Iron-induced FGF23 and SOX9 mRNA and protein expression in primary human normal chondrocyte cells (HUM-iCell-s018) was quantified by qRT-PCR and WB, respectively. RESULTS: We found that compared with OA patients, the expression of FGF23, MMP13 in articular cartilage of patients with HA was up-regulated, while the expression of SOX9, collagen Ⅱ was down-regulated. Iron-induced FGF23 and suppressed SOX9 expression in chondrocytes in a dose-dependent manner. CONCLUSIONS: These findings demonstrated that iron was involved in hemophilic cartilage lesion directly via changing cartilage phenotype through regulation of FGF23 and SOX9 expression in chondrocytes.

Pathological changes and expression of lysine oxidases and matrix metalloproteinases -1, -2, and -3 in ligaments of patients with haemophilic arthritis.

INTRODUCTION: Studying the pathological changes of ligaments in patients with haemophilic arthritis (HA) has important significance for guiding the release of ligaments during total knee arthroplasty (TKA) and exploring interventions to prevent ligament lesions. AIM: This study was conducted to show the pathological changes and investigate the lysine oxidase (LOX) and matrix metalloproteinase (MMP)-1, -2, and -3 levels in the ligaments of patients with HA compared with those of patients with osteoarthritis (OA). METHODS: Ligaments obtained during the TKA were stained with Masson trichrome, Verhoeff-Van Gieson and haematoxylin and eosin to show the basic pathological changes. Collagen I, elastin, LOXs and MMP-1, -2, and -3 expression levels were detected via western blot. LOX and MMP-1, -2, and -3 mRNA expression levels were analysed via quantitative real-time PCR. RESULTS: Compared with OA ligaments, HA ligaments were constructed more loosely with wider gaps, more breaks, haemocytodeposition and local hypertrophy among the fibres. LOXs and MMP mRNA expression levels were upregulated in the HA tissues, which was consistent with the western blot results. Collagen I and elastin levels were also higher in patients with HA. CONCLUSIONS: The metabolism of the ligaments in patients with HA is more complex than in those with OA, and the ligaments of patients with HA have stronger healing and destruction processes. This pathology is related to iron overload and imbalanced inflammatory factors due to repeated intra-articular bleeding.

Pre-colectomy location and TNM staging of colon cancer by the computed tomography colonography: a diagnostic performance study.

BACKGROUND: The Chinese Society of Clinical Oncology guidelines 2018 and the recent update of that (version 2020) recommends accurate examination before major treatment for decision(s) in cases of colon cancer. Also, the difficulty in the identification of the lesion during colectomy may lead to resection of a wrong segment of the colon or a more extensive resection than planned. Accurate pre-colectomy local staging of colon cancer is required to make decisions for treatment of colon cancer. The objective of the study was to evaluate the diagnostic performance of the computed tomography colonography (CTC) for pre-colectomy tumor location and tumor, node, and metastasis (TNM) staging of colon cancer. METHODS: Data of preoperative colonoscopies, CTC, surgeries, and surgical pathology of a total of 269 patients diagnosed with colon cancer by colonoscopy and biopsy and underwent pre-colectomy location and TNM staging by CTC were collected and analyzed. The consistency between the radiological and the surgery/surgical-pathological for location and TN stages of colon tumor were estimated with the weighted kappa or kappa coefficient (κ) at 95% confidence interval (CI). RESULTS: CTC detected 261 (93%) and colonoscopy detected 201 (72%) correct locations of tumors. Sensitivity and accuracy of CTC for detection of location of colon tumors were 100% and 92.58% (κ = 0.89; 95% Cl: 0.83-0.95). 72.48% sensitivity, 90.64% specificity, and 83.57% accuracy were reported for CTC in differentiation of tumors confined to the colon wall (T1/T2) from advanced tumors (T3/T4) (κ = 0.69, 95% Cl: 0.51-0.75). 81.01% sensitivity, 89.11% specificity, and 83.93% accuracy of CTC was reported for differentiation of tumors between low-intermediate risk and high risk (κ = 0.68, 95% Cl: 0.53-0.75). 69.31% sensitivity, 66.15% specificity, and 67.14% accuracy of CTC were reported for N staging of tumors (κ = 0.41, 95% Cl: 0.59-0.69). CONCLUSIONS: CTC has high diagnostic parameters for pre-colectomy location and T staging of colon tumors except patients of colon cancer who received neoadjuvant chemotherapy. LEVEL OF EVIDENCE: III. TECHNICAL EFFICACY STAGE: 2.

Variation in PM2.5 sources in central North China Plain during 2017-2019: Response to mitigation strategies.

Central North China Plain (NCP) is one of the most important source region of air pollutants over the Beijing-Tianjin-Hebei (BTH) region. The national government has issued abatement measures to improve the air quality in this area from 2017. To examine the effects of control measures, observational analysis on PM2.5 characteristics was performed in a city of central NCP during 2017-2019 to investigate the variation in mass concentration, chemical composition, and emission source of PM2.5. Annual PM2.5 concentration significantly reduced by 16% from 2017 to 2019, implying substantial improvements in air quality. PM2.5 enriched in autumn-winter seasons was dominated by SNA (sum of sulfate, nitrate and ammonium; ~38%), followed by organic carbon matters (OM; ~24%) and fine soil (FS; ~12%). This chemical composition was different from that in a megacity in NCP (Beijing) where OM accounted for a comparable fraction to SNA. Approximately half of SNA was attributed to nitrate, indicating that SNA changed from sulfate-driven to nitrate-driven, and the considerable effects of coal combustion cutoff, in which sulfate was concentrated. Decreased mass fraction of SNA and increased OM fraction in PM2.5 were observed in 2018-2019 partly contributed to the decrease in PM2.5. A progressive increase in the contribution of heterogeneous formed SNA whilst a decrease in OM was observed as the pollution elevated from clean to heavily polluted. Six sources (soil dust, biomass burning, secondary emission, road traffic, coal combustion and industry) were identified by the Positive Matrix Factorization (PMF) model in both years and dominated by secondary aerosols, respectively contributing 39% and 41% to PM2.5. The decreasing concentrations (with reductions of 17%-61%) of the secondary source, coal combustion, soil dust and biomass burning largely accounted for the reduction in PM2.5, as a consequence of the recent abatement measures. By contrast, contributions of vehicle-related emissions, similar to the increasing contribution of vehicles at sites in NCP after 2013, should receive increased attention.

Spatial Distribution and Environmental Risk of Arsenic and Antimony in Soil Around an Antimony Smelter of Qinglong County.

The purpose of this study was to investigate the distribution of arsenic (As) and antimony (Sb) in soils around an antimony smelter at Qinglong together with the soil pollution levels and potential ecological risk. The results show that (1) total concentrations of As (23 ~ 539 mg/kg) and Sb (19.7 ~ 5681 mg kg-1) were higher than the Guizhou province-level background values (As, 20; Sb, 2.24), especially Sb. Their dominant geochemical speciation was the residual fraction which accounted for > 90% of the total concentrations. (2) The distribution of As and Sb in soils influenced mainly by land-use type, altitude, predominant wind direction, and distance from the pollution source. (3) The geo-accumulation index shows that the soil was highly contaminated with Sb and moderately with As. The potential ecological risk index shows that As posed a moderate risk and Sb a high risk. The general ecological risk was classified as high risk. However, the risk index coding method shows low environmental risk from As and Sb.

Development and validation of an RNA binding protein-associated prognostic model for hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) is among the deadliest forms of cancer. While RNA-binding proteins (RBPs) have been shown to be key regulators of oncogenesis and tumor progression, their dysregulation in the context of HCC remains to be fully characterized. METHODS: Data from the Cancer Genome Atlas - liver HCC (TCGA-LIHC) database were downloaded and analyzed in order to identify RBPs that were differentially expressed in HCC tumors relative to healthy normal tissues. Functional enrichment analyses of these RBPs were then conducted using the GO and KEGG databases to understand their mechanistic roles. Central hub RBPs associated with HCC patient prognosis were then detected through Cox regression analyses, and were incorporated into a prognostic model. The prognostic value of this model was then assessed through the use of Kaplan-Meier curves, time-related ROC analyses, univariate and multivariate Cox regression analyses, and nomograms. Lastly, the relationship between individual hub RBPs and HCC patient overall survival (OS) was evaluated using Kaplan-Meier curves. Finally, find protein-coding genes (PCGs) related to hub RBPs were used to construct a hub RBP-PCG co-expression network. RESULTS: In total, we identified 81 RBPs that were differentially expressed in HCC tumors relative to healthy tissues (54 upregulated, 27 downregulated). Seven prognostically-relevant hub RBPs (SMG5, BOP1, LIN28B, RNF17, ANG, LARP1B, and NR0B1) were then used to generate a prognostic model, after which HCC patients were separated into high- and low-risk groups based upon resultant risk score values. In both the training and test datasets, we found that high-risk HCC patients exhibited decreased OS relative to low-risk patients, with time-dependent area under the ROC curve values of 0.801 and 0.676, respectively. This model thus exhibited good prognostic performance. We additionally generated a prognostic nomogram based upon these seven hub RBPs and found that four other genes were significantly correlated with OS. CONCLUSION: We herein identified a seven RBP signature that can reliably be used to predict HCC patient OS, underscoring the prognostic relevance of these genes.

Whole-Genome Sequencing Reveals Diverse Models of Structural Variations in Esophageal Squamous Cell Carcinoma.

Comprehensive identification of somatic structural variations (SVs) and understanding their mutational mechanisms in cancer might contribute to understanding biological differences and help to identify new therapeutic targets. Unfortunately, characterization of complex SVs across the whole genome and the mutational mechanisms underlying esophageal squamous cell carcinoma (ESCC) is largely unclear. To define a comprehensive catalog of somatic SVs, affected target genes, and their underlying mechanisms in ESCC, we re-analyzed whole-genome sequencing (WGS) data from 31 ESCCs using Meerkat algorithm to predict somatic SVs and Patchwork to determine copy-number changes. We found deletions and translocations with NHEJ and alt-EJ signature as the dominant SV types, and 16% of deletions were complex deletions. SVs frequently led to disruption of cancer-associated genes (e.g., CDKN2A and NOTCH1) with different mutational mechanisms. Moreover, chromothripsis, kataegis, and breakage-fusion-bridge (BFB) were identified as contributing to locally mis-arranged chromosomes that occurred in 55% of ESCCs. These genomic catastrophes led to amplification of oncogene through chromothripsis-derived double-minute chromosome formation (e.g., FGFR1 and LETM2) or BFB-affected chromosomes (e.g., CCND1, EGFR, ERBB2, MMPs, and MYC), with approximately 30% of ESCCs harboring BFB-derived CCND1 amplification. Furthermore, analyses of copy-number alterations reveal high frequency of whole-genome duplication (WGD) and recurrent focal amplification of CDCA7 that might act as a potential oncogene in ESCC. Our findings reveal molecular defects such as chromothripsis and BFB in malignant transformation of ESCCs and demonstrate diverse models of SVs-derived target genes in ESCCs. These genome-wide SV profiles and their underlying mechanisms provide preventive, diagnostic, and therapeutic implications for ESCCs.

Rapid Adaptation for Active Pantograph Control in High-Speed Railway via Deep Meta Reinforcement Learning.

Active pantograph control is the most promising technique for reducing contact force (CF) fluctuation and improving the train's current collection quality. Existing solutions, however, suffer from two significant limitations: 1) they are incapable of dealing with the various pantograph types, catenary line operating conditions, changing operating speeds, and contingencies well and 2) it is challenging to implement in practical systems due to the lack of rapid adaptability to a new pantograph-catenary system (PCS) operating conditions and environmental disturbances. In this work, we alleviate these problems by developing a revolutionary context-based deep meta-reinforcement learning (CB-DMRL) algorithm. The proposed CB-DMRL algorithm combines Bayesian optimization (BO) with deep reinforcement learning (DRL), allowing the general agent to adapt to new tasks quickly and efficiently. We evaluated the CB-DMRL algorithm's performance on a proven PCS model. The experimental results demonstrate that meta-training DRL policies with latent space swiftly adapt to new operating conditions and unknown perturbations. The meta-agent adapts quickly after two iterations with a high reward, which require only ten spans, approximately equal to 0.5 km of PCS interaction data. Compared with state-of-the-art DRL algorithms and traditional solutions, the proposed method can promptly traverse scenario changes and reduce CF fluctuations, resulting in an excellent performance.

Investigating the impact of two representative nitro explosives on the thermal decomposition mechanism of DNTF through ab initio molecular dynamics.

CONTEXT: To investigate the influence of two typical nitro explosives, 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) and nitroguanidine (NQ), on the thermal decomposition mechanism of 3,4-Bis (3-nitrofurazan-4-yl) furoxan (DNTF). The study simulates the dynamical behavior of the DNTF/DNTF, DNTF/NQ, and DNTF/LLM-105 systems at different temperatures. We analyzed their thermal decomposition mechanisms through decomposition processes, reaction paths, and product evolution. Building on our analysis of thermal decomposition mechanisms, we found that introducing these two components (NQ and LLM-105) significantly alters the decomposition mechanism of DNTF. This introduction promotes the breakdown of DNTF molecules, modifies the thermal decomposition processes, and consequently changes the reaction pathways. In the DNTF/DNTF system, the product C3N4O4 remains stable, while the N-O bond in NO2 undergoes repeated breaking and formation, ultimately converting into NO. Conversely, in the mixed system, NO2 persists throughout the simulation, while the reaction product C3N4O4 undergoes additional reactions and eventually disappears at higher temperatures. This behavioral disparity determines distinct decomposition mechanisms between the mixed and pure DNTF systems. METHODS: To investigate the thermal decomposition mechanisms of DNTF/LLM-105 and DNTF/NQ composite energetic materials, the first-principles calculation software CP2K is used. The GFNI-xTB (Geometry, Frequency, and Noncovalent, eXtended Tight Binding) program within CP2K is employed. This method provides a powerful tool for performing calculations with arbitrary accuracy on complex systems.

Denosumab combined with microwave ablation excisional scraping for giant cell tumor of the thoracic spine: a case report and literature review.

Denosumab has recently become an important part of the treatment regime for spinal giant cell tumors of the bone (GCTB). Its use has significantly reduced the risk of surgery and postoperative complications in patients with spinal GCTB. However, the use of denosumab has not yet been optimized to reap the maximum benefits. Here, we have reported the case of a patient who was treated with denosumab in combination with excision and scraping for GCTB of the T10 vertebrae, which achieved good tumor control and no recurrence at the 2-year postoperative follow-up. We have also reviewed the case in the light of relevant literature as well as presented our ideas and recommendations for the optimal use of denosumab.

A new technique of percutaneous minimally invasive surgery assisted by magnetic resonance neurography.

Aims: In order to release the contracture band completely without damaging normal tissues (such as the sciatic nerve) in the surgical treatment of gluteal muscle contracture (GMC), we tried to display the relationship between normal tissue and contracture bands by magnetic resonance neurography (MRN) images, and to predesign a minimally invasive surgery based on the MRN images in advance. Methods: A total of 30 patients (60 hips) were included in this study. MRN scans of the pelvis were performed before surgery. The contracture band shape and external rotation angle (ERA) of the proximal femur were also analyzed. Then, the minimally invasive GMC releasing surgery was performed based on the images and measurements, and during the operation, incision lengths, surgery duration, intraoperative bleeding, and complications were recorded; the time of the first postoperative off-bed activity was also recorded. Furthermore, the patients' clinical functions were evaluated by means of Hip Outcome Score (HOS) and Ye et al's objective assessments, respectively. Results: The contracture bands exhibited three typical types of shape - feather-like, striped, and mixed shapes - in MR images. Guided by MRN images, we designed minimally invasive approaches directed to each hip. These approaches resulted in a shortened incision length in each hip (0.3 cm (SD 0.1)), shorter surgery duration (25.3 minutes (SD 5.8)), less intraoperative bleeding (8.0 ml (SD 3.6)), and shorter time between the end of the operation and the patient's first off-bed activity (17.2 hours (SD 2.0)) in each patient. Meanwhile, no serious postoperative complications occurred in all patients. The mean HOS-Sports subscale of patients increased from 71.0 (SD 5.3) to 94.83 (SD 4.24) at six months postoperatively (p < 0.001). The follow-up outcomes from all patients were "good" and "excellent", based on objective assessments. Conclusion: Preoperative MRN analysis can be used to facilitate the determination of the relationship between contracture band and normal tissues. The minimally invasive surgical design via MRN can avoid nerve damage and improve the release effect.

Disentangling sources and transformation mechanisms of nitrogen, sulfate, and carbon in water of a Karst Critical Zone.

In the Karst Critical Zone (KCZ), mining and urbanization activities produce multiple pollutants, posing a threat to the vital groundwater and surface water resources essential for drinking and irrigation. Despite their importance, the interactions between these pollutants in the intricate hydrology and land use of the KCZ remain poorly understood. In this study, we unraveled the transformation mechanisms and sources of nitrogen, sulfate, and carbon using multiple isotopes and the MixSIAR model, following hydrology and surface analyses conducted in spatial modelling with ArcGIS. Our results revealed frequent exchange between groundwater and surface water, as evidenced by the analysis of δD-H2O and δ18O-H2O. Nitrification predominantly occurred in surface water, although denitrification also made a minor contribution. Inorganic nitrogen in both groundwater and surface water primarily originated from soil nitrogen (48 % and 49 %, respectively). Sewage and manure were secondary sources of inorganic nitrogen in surface water, accounting for 41 % in urban and 38 % in mining areas. Notably, inorganic sulfur oxidation displayed significant spatial disparities between urban and mining areas, rendering groundwater more susceptible to sulfur pollution compared to surface water. The frequent interchange between groundwater and surface water posed a higher pollution risk to groundwater. Furthermore, the primary sources of CO2 and HCO3- in both groundwater and surface water were water­carbonate reactions and soil respiration. Sulfide oxidation was found to enhance carbonate dissolution, leading to increased CO2 release from carbonate dissolution in the KCZ. These findings enhance our understanding of the transformation mechanisms and interactions of nitrogen, sulfur, and carbon in groundwater and surface water. This knowledge is invaluable for accurately controlling and treating water pollution in the KCZ.

Temporal and spatial distribution characteristics and source analysis of dissolved organic nitrogen in the surface sediment of the Caohai Lake, southwest China.

Caohai Lake is a typical natural lake-type karst plateau wetland, which is sensitive to environmental changes, and the release of dissolved organic nitrogen (DON) in sediment is a potential factor of nitrogen pollution in this lake. Therefore, we aimed to reveal the temporal and spatial distribution characteristics and source analysis of DON in karst lake sediment. Surface sediment samples were collected from Caohai Lake in southwest China, and the sample locations were distributed across almost the entire wetland area, during both the wet and dry seasons. The DON content and fluorescence spectroscopy were determined and analysed using a three-dimensional fluorescence-parallel factor analysis (3DEEM-PARAFAC) model. The mean DON content in the sediment during the dry season (67.79 ± 42.96 mg/kg) was higher than that in the wet season (28.57 ± 20.97 mg/kg). There were four fluorescent components of DON in the sediment: C1 (tyrosine-like protein), C2 (terrestrial humus), C3 (tryptophan-like protein) and C4 (terrestrial humus). The DON in the surface sediment of Caohai Lake was influenced by terrestrial sources and biological activities. These findings help reveal the circulation mechanism of endogenous nitrogen in the lake and provide theoretical support for the prevention and control of nitrogen pollution in Caohai Lake.

Radiative effects and feedbacks of anthropogenic aerosols on boundary layer meteorology and fine particulate matter during the COVID-19 lockdown over China.

The COVID-19 epidemic has exerted significant impacts on human health, social and economic activities, air quality and atmospheric chemistry, and potentially on climate change. In this study, an online coupled regional climate-chemistry-aerosol model (RIEMS-Chem) was applied to explore the direct, indirect, and feedback effects of anthropogenic aerosols on radiation, boundary layer meteorology, and fine particulate matter during the COVID-19 lockdown period from 23 January to 8 April 2020 over China. Model performance was validated against a variety of observations for meteorological variables, PM2.5 and its chemical components, aerosol optical properties, as well as shortwave radiation flux, which demonstrated that RIEMS-Chem was able to reproduce the spatial distribution and temporal variation of the above variables reasonably well. During the study period, direct radiative effect (DRE) of anthropogenic aerosols was stronger than indirect radiative effect (IRE) in most regions north of the Yangtze River, whereas IRE dominated over DRE in the Yangtze River regions and South China. In North China, DRE induced larger changes in meteorology and PM2.5 than those induced by IRE, whereas in South China, the changes by IRE were remarkably larger than those by DRE. Emission reduction alone during the COVID-19 lockdown reduced PM2.5 concentration by approximately 32 % on average over East China. As a result, DRE at the surface was weakened by 15 %, whereas IRE changed little over East China, leading to a decrease in total radiative effect (TRE) by approximately 7 % in terms of domain average. The DRE-induced changes in meteorology and PM2.5 were weakened due to emission reduction, whereas the IRE-induced changes were almost the same between the cases with and without emission reductions. By aerosol radiative and feedback effects, the COVID-19 emission reductions resulted in 0.06 °C and 0.04 °C surface warming, 1.6 and 4.0 µg m-3 PM2.5 decrease, 0.4 and 1.3 mm precipitation increase during the lockdown period in 2020 in terms of domain average over North China and South China, respectively, whereas the lockdown caused negligible changes on average over East Asia.