Microbial community structure in an uranium-rich acid mine drainage site: implication for the biogeochemical release of uranium

The generation of acid mine drainage (AMD) characterized by high acidity and elevated levels of toxic metals primarily results from the oxidation and dissolution of sulfide minerals facilitated by microbial catalysis. Although there has been significant research on microbial diversity and community composition in AMD, as well as the relationship between microbes and heavy metals, there remains a gap in understanding the microbial community structure in uranium-enriched AMD sites. In this paper, water samples with varying levels of uranium pollution were collected from an abandoned stone coal mine in Jiangxi Province, China during summer and winter, respectively. Geochemical and high-throughput sequencing analyses were conducted to characterize spatiotemporal variations in bacterial diversity and community composition along pollution groups. The results indicated that uranium was predominantly concentrated in the AMD of new pits with strong acid production capacity, reaching a peak concentration of 9,370 μg/L. This was accompanied by elevated acidity and concentrations of iron and total phosphorus, which were identified as significant drivers shaping the composition of bacterial communities, rather than fluctuations in seasonal conditions. In an extremely polluted environment (pH < 3), bacterial diversity was lowest, with a predominant presence of acidophilic iron-oxidizing bacteria (such as Ferrovum), and a portion of acidophilic heterotrophic bacteria synergistically coexisting. As pollution levels decreased, the microbial community gradually evolved to cohabitation of various pH-neutral heterotrophic species, ultimately reverting back to background level. The pH was the dominant factor determining biogeochemical release of uranium in AMD. Acidophilic and uranium-tolerant bacteria, including Ferrovum, Leptospirillum, Acidiphilium, and Metallibacterium, were identified as playing key roles in this process through mechanisms such as enhancing acid production rate and facilitating organic matter biodegradation

The Method of Particular Solutions Using Trigonometric Basis Functions

In this paper, the method of particular solutions (MPS) using trigonometric functions as the basis functions is proposed to solve two-dimensional elliptic partial differential equations. The inhomogeneous term of the governing equation is approximated by Fourier series and the closed-form particular solutions of trigonometric functions are derived using the method of undetermined coefficients. Once the particular solutions for the trigonometric basis functions are derived, the standard MPS can be applied for solving partial differential equations. In comparing with the use of radial basis functions and polynomials in the MPS, our proposed approach provides another simple approach to effectively solving two-dimensional elliptic partial differential equations. Five numerical examples are provided in this paper to validate the merits of the proposed meshless method

Accounting, Ideological and Political Work and Chinese Multinational Operations: A Neo-Gramscian Perspective

This paper critically analyses the role of accounting in China’s new phase of politically driven economic reforms, which is the international expansion of Chinese enterprises. In particular, the paper examines how China’s multinational state-owned enterprise (SOE) and its managers conceive of, and use, accounting and control practices in response to the state’s international political and economic objectives. Drawing upon neo-Gramscian concepts of hegemony, this study contends that the Chinese Communist Party (CCP) has sought to create and maintain its hegemony by turning its political ideologies into initiatives of “economic development”, articulated through intensive ideological and political work exercised from the national to the organisational level. The study highlights the role of SOE managers in accommodating accounting and control practices in line with the state’s hegemonic and ideological demands. Crucially, it reveals the ability of managers to coordinate and balance the state’s political ends and the enterprise’s economic interests, where there is a selective use of accounting and control practices deployed for reasons beyond their economic functionality. This paper argues that it is necessary to include the superstructure and economic base of the Chinese state in a hegemonic analysis, and to investigate how the managerial cadre engages with ideology building at the organisational level. By focusing on the Chinese state’s new political dynamism regarding the expansion of multinational business operations, this paper provides new insights into the complexity of the motivations underlying the use of accounting and control practices in a globalised context

Correlation study between advanced age and inferior prognosis in stage Ⅱ colorectal cancer patients

Background and purpose: With the aging population, the number of elderly patients with colorectal cancer (CRC) is increasing. To date, elderly patients with stage Ⅱ CRC often receive a weakened chemotherapy regimen or even no chemotherapy after radical surgery, and It is still unclear whether this will lead to adverse oncological outcomes. This study aimed to explore the prognostic impact of advanced age on stage Ⅱ CRC patients after removing bias through a multivariate COX regression approach. Methods: We retrospectively collected data of 3314 colorectal cancer patients with postoperative pathology of stage Ⅱ, no history of previous tumors, no secondary primary tumors within 5 years after surgery and no preoperative neoadjuvant therapy. This study was reviewed by the medical ethics committee of Fudan University Shanghai Cancer Center (ethics number: 050432-4-2108*). The optimal threshold for calculating age relative to survival using survminer package of R software (version 3.0) (surv_cutpoint algorithm) was 73 years. We compared the clinical and pathological characteristics, overall survival (OS) and disease-free survival (DFS) between the older group (age>73 years) and the younger group (age≤73 years). The alignment diagram prediction model was drawn using the survival package and RMS package. Results: The elderly and non-elderly groups were evenly comparable in terms of gender, tumor location, differentiation, vascular invasion, perineural invasion and pT stage. Multivariate COX regression showed that advanced age was an independent prognostic risk factor for OS [hazard ratio (HR)=3.725 (3.051-4.549), P<0.001] and DFS [HR=2.431 (2.029-2.912), P<0.001]. The nomogram (alignment diagram) prediction model constructed based on multivariate COX regression could effectively evaluate the prognosis of stage Ⅱ CRC patients and provide guidance for practical clinical work. Conclusion: In stage Ⅱ CRC patients, older age is associated with shorter OS and DFS. Adequate intensity of adjuvant chemotherapy may be necessary. Treatment decisions can be adjusted based on the predicted model scores of the patient’s alignment diagram

Evaluating the Guiding Role of Elevated Pretreatment Serum Carcinoembryonic Antigen Levels for Adjuvant Chemotherapy in Stage IIA Colon Cancer: A Large Population-Based and Propensity Score-Matched Study

Objective: This study was to investigate guiding role of elevated pretreatment serum carcinoembryonic antigen (CEA) levels for ACT receipt in stage IIA colon cancer.Methods: Eligible patients diagnosed with stage IIA colon cancer (N = 21848) were identified from the Surveillance, Epidemiology, and End Results (SEER) database between January 2004 and December 2010. Pearson's chi-squared tests, Cox proportional hazards regression models, and Kaplan-Meier methods were performed. Propensity score matching (PSM) was used to decrease the risk of biased estimates of treatment effect.Results: Multivariate Cox analysis indicated that, in CEA-elevated group, receiving or not receiving ACT did not presented statistically CSS difference [hazard ratio (HR) = 0.940, 95% confidence interval (CI) = 0.804–1.097, P = 0.431]; in CEA-normal group, receiving or not receiving ACT also did not presented statistically CSS difference (HR = 0.911, 95% CI = 0.779–1.064, P = 0.239). After PSM, Kaplan-Meier analyses showed that there was no statistical CSS difference between receiving or not receiving ACT (P = 0.64).Conclusion: ACT did not show substantial survival benefit in stage IIA colon cancer with elevated pretreatment serum CEA levels. Stage IIA disease with elevated pretreatment serum CEA should not be treated with ACT

Performance of the suspension method in large cross-section shallow-buried tunnels

Large cross-section tunnel construction induces ground surface settlements, potentially endangering both subterranean projects and nearby above-ground structures. A novel tunnel construction method, known as the suspension method, is introduced in this paper to mitigate surface settlement. The suspension method employs vertical tie rods to establish a structural connection between the initial tunnel support system and the surface steel beam, thereby exerting effective control settlements. To analyze the performance of the proposed method, systematic numerical simulations were conducted based on the practical engineering of Harbin Subway Line 3. The surface settlement and vault settlement characteristics during construction are investigated. The results show a gradual increment in both surface and vault settlement throughout the construction process, culminating in a stabilized state upon the completion of construction. In addition, compared to the double-side drift method and the Cross Diaphragm Method (CRD) method, the suspension method can obviously reduce the surface settlement and vault settlement. Moreover, the surface settlements and the axial force of tie rods were continuously monitored during the construction process at the trial tunnel block. These specific monitoring measurements are illustrated in comparison to numerical analysis results. The monitored results show great agreement with the numerical predictions, confirming the success of the project. This research can serve as a valuable practical reference for similar projects, offering insights and guidance for addressing ground surface settlements and enhancing construction safety in the domain of large cross-section tunneling

Toxicity of microcystins in the isolated hepatocytes of common carp (Cyprinus carpio L.)

The toxicity of hepatotoxic microcystins produced mainly by Microcystis aeruginosa in mammals and fishes was well studied in recent years. However, there were scarcely reports in toxic effects of microcystins on isolated hepatocytes of fishes, especially investigation of microcystin-induced apoptosis and/or necrosis in carp hepatocytes. In the present study, the isolated hepatocytes of common carp were exposed to various concentrations of microcystins (0.01, 0.1, 1, 10, 100, 1000 mu g L-1) for 2, 4, 8, 16 and 24 h, respectively, and cytotoxicity of microcystins in the toxin-treated cells was determined. Results of this study showed that cytotoxicity of microcystins on carp hepatocytes was time and dose-dependent, and the approximate LC50 of microcystins in carp hepatocytes was 169.2 mu g L-1. The morphological changes typical of apoptosis, such as blebbing of cell membrane, condensation and fragmentation of cell nucleus were observed in the hepatocytes exposed to microcystins (1, 10 and 100 mu g L-1) using fluorescence and differential interference contrast microscopy. Agarose gel electrophoresis of DNA demonstrated a typical apoptotic "ladder pattern" in microcystin-treated hepatocytes after 16 h of exposure. Results of the present study indicated that the form of cell death in microcystin-treated hepatocytes depend on the exposure dose of toxin. When lower concentration of microcystins (10 and 100 mu g L-1) was used for exposure, carp hepatocytes died in apoptosis while, when higher one used (1000 mu g L-1), they died in the form of necrosis. (C) 2006 Elsevier Inc. All rights reserved.The toxicity of hepatotoxic microcystins produced mainly by Microcystis aeruginosa in mammals and fishes was well studied in recent years. However, there were scarcely reports in toxic effects of microcystins on isolated hepatocytes of fishes, especially investigation of microcystin-induced apoptosis and/or necrosis in carp hepatocytes. In the present study, the isolated hepatocytes of common carp were exposed to various concentrations of microcystins (0.01, 0.1, 1, 10, 100, 1000 mu g L-1) for 2, 4, 8, 16 and 24 h, respectively, and cytotoxicity of microcystins in the toxin-treated cells was determined. Results of this study showed that cytotoxicity of microcystins on carp hepatocytes was time and dose-dependent, and the approximate LC50 of microcystins in carp hepatocytes was 169.2 mu g L-1. The morphological changes typical of apoptosis, such as blebbing of cell membrane, condensation and fragmentation of cell nucleus were observed in the hepatocytes exposed to microcystins (1, 10 and 100 mu g L-1) using fluorescence and differential interference contrast microscopy. Agarose gel electrophoresis of DNA demonstrated a typical apoptotic "ladder pattern" in microcystin-treated hepatocytes after 16 h of exposure. Results of the present study indicated that the form of cell death in microcystin-treated hepatocytes depend on the exposure dose of toxin. When lower concentration of microcystins (10 and 100 mu g L-1) was used for exposure, carp hepatocytes died in apoptosis while, when higher one used (1000 mu g L-1), they died in the form of necrosis. (C) 2006 Elsevier Inc. All rights reserved