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Groundwater is susceptible to arsenic contamination by sediment with high arsenic content, which is the primary culprit of regional arsenic pollution and poisoning. To explore the influence of the change in hydrodynamic conditions caused by changes in the sedimentary environment over time on arsenic content in sediments during the Quaternary, the hydrodynamic characteristics and arsenic content enrichment of borehole sediments were studied in typical high-arsenic groundwater areas of the Jianghan–Dongting Basin, China. The regional hydrodynamic conditions represented by each borehole location were analyzed, the correlation between the variation in groundwater dynamics characteristics and arsenic content in different hydrodynamic periods was analyzed, and the relationship between arsenic content and grain size distribution was quantitatively investigated using grain size parameter calculation, elemental analysis, and statistical estimates of arsenic content in borehole sediments. We observed that the relationship between arsenic content and hydrodynamic conditions differed between sedimentary periods. Furthermore, arsenic content in the sediments from the borehole at Xinfei Village was significantly and positively correlated with a grain size of 127.0–240.0 μm. For the borehole at Wuai Village, arsenic content was significantly and positively correlated with a grain size of 1.38–9.82 μm size (at 0.05 level of significance). However, arsenic content was inversely correlated with grain sizes of 110.99–716.87 and 133.75–282.07 μm at p values of 0.05 and 0.01, respectively. For the borehole at Fuxing Water Works, arsenic content was significantly and positively correlated with a grain size of 409.6–655.0 μm size (at 0.05 level of significance). Arsenic tended to be enriched in transitional and turbidity facies sediments with normal corresponding hydrodynamic strength but poor sorting. Furthermore, continuous and stable sedimentary sequences were conducive to arsenic enrichment. Fine-grain sediments provided abundant potential adsorption sites for high-arsenic sediments, but finer particle size was not correlated with higher arsenic levels. [ABSTRACT FROM AUTHOR]

Purpose: Fruit intake is beneficial to several chronic diseases, but controversial in diabetes. We aimed to investigate prospectively the associations of whole fresh fruit intake with risk of incident type 2 diabetes (T2D) in subjects with different glucose regulation capacities. Methods: The present study included 79,922 non-diabetic participants aged ≥ 40 years from an ongoing nationwide prospective cohort in China. Baseline fruit intake information was collected by a validated food frequency questionnaire. Plasma HbA1c, fasting and 2 h post-loading glucose levels were measured at both baseline and follow-up examinations. Cox proportional hazards models were used to calculate hazard ratio (HR) and 95% confidence intervals (CI) for incident diabetes among participants with normal glucose tolerance (NGT) and prediabetes, after adjusted for multiple confounders. Restricted cubic spline analysis was applied for dose–response relation. Results: During a median 3.8-year follow-up, 5886 (7.36%) participants developed diabetes. Overall, we identified a linear and dose-dependent inverse association between dietary whole fresh fruit intake and risk of incident T2D. Each 100 g/d higher fruit intake was associated with 2.8% lower risk of diabetes (HR 0.972, 95%CI [0.949–0.996], P = 0.0217), majorly benefiting NGT subjects with 15.2% lower risk (HR 0.848, 95%CI [0.766–0.940], P = 0.0017), while not significant in prediabetes (HR 0.981, 95%CI 0.957–4.005, P = 0.1268). Similarly, the inverse association was present in normoglycemia individuals with a 48.6% lower risk of diabetes when consuming fruits > 7 times/week comparing to those < 1 time/week (HR 0.514, 95% CI [0.368–0.948]), but not in prediabetes (HR 0.883, 95% CI [0.762–1.023]). Conclusion: These findings suggest that higher frequency and amount of fresh fruit intake may protect against incident T2D, especially in NGT, but not in prediabetes, highlighting the dietary recommendation of higher fresh fruit consumption to prevent T2D in normoglycemia population. [ABSTRACT FROM AUTHOR]

Objectives: To reconstruct the genomic epidemiology and evolution of MDR Salmonella Indiana in China.Methods: A total of 108 Salmonella Indiana strains were collected from humans and livestock in China. All isolates were subjected to WGS and antimicrobial susceptibility testing. Phylogenetic relationships and evolutionary analyses were conducted using WGS data from this study and the NCBI database.Results: Almost all 108 Salmonella Indiana strains displayed the MDR phenotype. Importantly, 84 isolates possessed concurrent resistance to ciprofloxacin and cefotaxime. WGS analysis revealed that class 1 integrons on the chromosome and IncHI2 plasmids were the key vectors responsible for multiple antibiotic resistance gene (ARG) [including ESBL and plasmid-mediated quinolone resistance (PMQR) genes] transmission among Salmonella Indiana. The 108 Salmonella Indiana dataset displayed a relatively large core genome and ST17 was the predominant ST. Moreover, the global ST17 Salmonella Indiana strains could be divided into five distinct lineages, each of which was significantly associated with a geographical distribution. Genomic analysis revealed multiple antimicrobial resistance determinants and QRDR mutations in Chinese lineages, which almost did not occur in other global lineages. Using molecular clock analysis, we hypothesized that ST17 isolates have existed since 1956 and underwent a major population expansion from the 1980s to the 2000s and the genetic diversity started to decrease around 2011, probably due to geographical barriers, antimicrobial selective pressure and MDR, favouring the establishment of this prevalent multiple antibiotic-resistant lineage and local epidemics.Conclusions: This study revealed that adaptation to antimicrobial pressure was possibly pivotal in the recent evolutionary trajectory for the clonal spread of ST17 Salmonella Indiana in China. [ABSTRACT FROM AUTHOR]

Copyright of Hydrogeology Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objectives: To investigate the prevalence and molecular characteristics of fosA3 and fosA7 among Salmonella isolates.Methods: Five hundred and fifty-one Salmonella isolates collected from food animals in China during 2016-19 were screened for fos genes. The drug resistance, serovars, clonal relationships and genetic environments of fosA were compared between fosA7- and fosA3-positive Salmonella.Results: A relatively high prevalence of fosA7 (9.26%) and fosA3 (6.53%) was identified. fosA3 was associated with high-level fosfomycin resistance (≥512 mg/L), while fosA7 conferred relatively low-level resistance that was independent of the presence of glucose-6-phosphate. Additionally, fosA7 could facilitate Salmonella survival under oxidative stress. Both fosA3 and fosA7 were found in diverse serovars and STs, but segregated into distinct groups. The fosA3-positive Salmonella Typhimurium/Salmonella Indiana strains showed close genetic relationships, while fosA7-positive Salmonella Meleagridis/Salmonella Agona/Salmonella Derby showed a relatively high degree of whole-genome sequence heterogeneity. fosA3 was located on conjugative IncHI2 plasmids or chromosomes, while fosA7 was strictly chromosomal. Furthermore, two strains carried large chromosomal fosA7 regions within genomic islands. The fosA3 and fosA7 contigs from our isolates and the NCBI could be segregated into four primary and distinct genomic backbones. IS26 and the antibiotic resistance genes (ARGs) blaCTX-M, blaTEM-1B and rmtB were frequently adjacent to fosA3, while fosA7-carrying contigs generally lacked mobile elements and ARGs.Conclusions: fosA3 and fosA7 were the primary factors contributing to reduced fosfomycin susceptibility, to different degrees, in these Salmonella isolates. The distinct distributions and molecular characteristics of fosA7 and fosA3 indicated that their origin and evolution in Salmonella were most likely distinct. [ABSTRACT FROM AUTHOR]

Objectives: To determine the transmission and molecular characteristics of blaNDM-producing Escherichia coli between companion animals and their healthcare providers at veterinary clinics in Guangzhou, China.Methods: A total of 359 samples from companion animals and their healthcare providers were collected at 14 veterinary clinics in Guangzhou, China. Genomic characteristics and clonal relationships for blaNDM-positive E. coli and complete plasmid sequences were characterized based on WGS data from combined Illumina and MinION platform reads.Results: Forty-five blaNDM-positive bacteria were recovered from companion animals (n = 43) and their healthcare providers (n = 2) at 10 veterinary clinics. Overall, E. coli (73.3%, 33/45) and Klebsiella pneumoniae (13.3%, 6/45) were the most prevalent species among the seven species of blaNDM-positive bacteria. Four blaNDM variants (blaNDM-1, blaNDM-4, blaNDM-5 and blaNDM-7) were identified in 45 blaNDM-positive bacteria and blaNDM-5 was the most prevalent (77.8%, 35/45). WGS indicated that the most prevalent STs were ST405 (8/33), ST453 (6/33), ST457 (6/33) and ST410 (5/33) among the 33 blaNDM-positive E. coli isolates. Phylogenomics and PFGE analysis revealed that clonal spread of blaNDM-positive ST453 E. coli isolates between companion animals and their healthcare providers was evident. In addition, two novel IncFIB plasmids carrying blaNDM-4 (pF765_FIB and pG908_FIB) were found in this study and indicated that IS26 may promote the horizontal transmission of blaNDM between different plasmid types.Conclusions: In this study we conducted a large-scale investigation on the prevalence of blaNDM-positive E. coli isolates from companion animals and their healthcare providers and revealed the clonal spread of blaNDM-positive E. coli isolates between these two groups. [ABSTRACT FROM AUTHOR]

Introduction: Some encouraging findings of Chinese herbal medicine (CHM) in management of idiopathic membranous nephropathy (IMN) obtained in the setting of clinical trials are hard to validate in the daily clinical practice due to a complicated treatment scenario of CHM in practice. The primary objective of this registry is to provide a description of treatment patterns used in management of IMN and assess clinical remission in daily practice in a Chinese population sample with IMN. Methods and analysis: This is a prospective, multicenter cohort which will comprise 2000 adults with IMN regardless of urinary protein levels that will be recruited from 11 nephrology centers across China. The participants will be followed for up to at least 2 years. Primary outcome is composite remission (either complete remission or partial remission) 24 months after enrolment. The secondary outcomes are complete remission, partial remission, time to remission, no response, relapse, proteinuria, annual change of glomerular filtration rate, antibodies against PLA2R, and composite endpoint of 40% reduction of glomerular filtration rate, doubling of serum creatinine, end-stage renal disease, and death. Propensity score analysis will be used for matching and adjustment. Ethics and dissemination: This study has been approved by the Ethics Committee of Guangdong Provincial Hospital of Chinese Medicine (BF2020-094-01). Results of the study will be published in both national and international peer-reviewed journals, and presented at scientific conferences. Investigators will inform the participants as well as other IMN patients of the findings via health education. Study registration : ChiCTR2000033680 (prospectively registered). [ABSTRACT FROM AUTHOR]

The naturally formed aeolian sand dunes in northern Shaanxi exhibit unique engineering characteristics. Several challenges, such as the poor self-stabilization ability of the surrounding rock, difficultly in injecting grout, and insufficient construction experience, restrict the construction of road tunnels under this stratum. Therefore, in this study, a case study of the Shenmu No. 1 tunnel was conducted to investigate the engineering characteristics of aeolian sand tunnels, compare the grouting effects of commonly used grouting materials, and discuss the reinforcement effects of different construction schemes in aeolian sand tunnels. Based on a field grouting test, it was determined that it is difficult to inject ordinary cement grout into an aeolian sand layer. Furthermore, it was determined that superfine cement grout and modified sodium silicate grout can be injected, but the former exhibits a poor reinforcement effect. Additionally, results of numerical analysis indicated that an approach based on a concept of "horizontal jet grouting pile + benching partial excavation method with a temporary invert" is suitable for the construction of tunnels in aeolian sand in China. [ABSTRACT FROM AUTHOR]

Reconstruction of sedimentary evolution plays a significant role in the investigation of natural groundwater contamination and stratigraphic mineral resources. In this paper, the variation in sedimentary characteristics and sedimentary evolution were studied by lithology, chronology and organic matter with the high-resolution grain size parameters of boreholes for Quaternary in northern Jianghan Basin. Following more traditional plotting of grain size parameters and summary statistics, visual categorization and analysis of grain size frequency distribution curves provided an effective measure for the identification of sedimentary facies. Combining with the Fisher model, new and highly efficient discriminant formulas were established, and tested for the validity. Additionally, the sedimentary evolution process and the provenance of different sedimentary facies were identified with the help of organic matter and δ 13C org data, provided geological information to explore the natural contamination of reducing arsenic ions and excessive nitrate in strata. The identification results suggest that fluvial and lacustrine sediments are dominant in the area, and the regional sedimentary environment is uniform and not affected by the transgression. The analysis results of grain size with organic matter parameters are consistent for discriminating sedimentary facies, which verified the rationality of grain size analysis and confirmed the use of organic matter content to be effective in identifying the process of fluvial and lacustrine sediments. Based on the chronological results of Optically Stimulated Luminescence dating and sedimentary facies determination, the sedimentary evolutionary process was deduced during the Quaternary for the study area. This research has important significance for the division and correlation of Quaternary borehole strata, underground contamination study, as well as environmental planning and protection. [Display omitted] [ABSTRACT FROM AUTHOR]

Objectives: To determine the dissemination and molecular characteristics of NDM-producing Escherichia coli strains from duck farms in south-east coastal China and their threats to human health.Methods: A total of 232 NDM-producing E. coli were recovered from 1505 samples collected from 25 duck farms and their surrounding environments in five provinces in China. Resistance genes were confirmed using PCR. Genomic characteristics of the carbapenemase-producing isolates were determined by WGS and bioinformatic analysis.Results: The rate of NDM-positive E. coli detected in samples from the five provinces ranged from 3.7% to 28.5%. There was substantial variation in the prevalence of NDM-positive E. coli from different duck farms in each province studied. Three variants (blaNDM-1, blaNDM-4 and blaNDM-5) were found in 232 NDM-positive E. coli; blaNDM-5 (94.8%, 220/232) was the most prevalent. WGS analysis indicated that ST746, ST48, ST1011 and ST167 E. coli isolates were prevalent in the current study and poultry was likely the primary reservoir for NDM-positive ST746 and ST48 E. coli in China. Phylogenomic analysis showed that NDM-positive E. coli isolates from ducks were closely related to those of human origin. In addition, WGS analysis further revealed that blaNDM co-existed with other antibiotic resistance genes, conferring resistance to nine classes of antimicrobials.Conclusions: This study revealed that ducks farm in China are an important reservoir for NDM-positive E. coli and STs of the isolates showed obvious distinctive diversities in geographical distribution. The distribution and spread of NDM-positive E. coli in duck farms poses a threat to public health. [ABSTRACT FROM AUTHOR]

Under the combined impacts of the operation time, design concept, and construction technology, extensive damage has occurred in tunnels built in China during the early stages of rapid development. Therefore, relevant research on tunnel damage is of urgent importance. This study takes the Liupanshan Highway Tunnel on G312 in Guyuan City as a case study, and uses field investigations, radar scans, and other methods to investigate the occurrence of a series of defects in the tunnel, including lining splitting, water leakage, and tunnel bottom damage, to analyze the damage characteristics and occurrence mechanism in detail based on both external causes and internal causes. From the results, by combing relevant materials both in China and abroad with the engineering characteristics, a comprehensive management method for reinforcing and strengthening damaged tunnels with a reinforced concrete umbrella arch is proposed. At the same time, considering the degradation in the bearing capacity of the existing lining structure and utilization degree of the bearing capacity of newly increased reinforced concrete umbrella arch, this study performs a theoretical analysis of the calculation for the safety factor of the reinforced damaged tunnel. The calculation results show that the reinforced Liupanshan Tunnel is in a secure state, which can provide references for similar projects in the future. [ABSTRACT FROM AUTHOR]

As an important pilot target for shale gas exploration and development in China, the Longmaxi Formation shale in the Dianqianbei Area is characterized by high content of nitrogen, which severely increases exploration risk. Accordingly, this study explores the genesis of shale gas reservoir and the mechanism of nitrogen enrichment through investigating shale gas compositions, isotope features, and geochemical characteristics of associated gases. The high-nitrogen shale gas reservoir in the Longmaxi Formation is demonstrated to be a typical dry gas reservoir. Specifically, the alkane carbon isotope reversal is ascribed to the secondary cracking of crude oil and the Rayleigh fractionation induced by the basalt mantle plume. Such a thermogenic oil-type gas reservoir is composed of both oil-cracking gas and kerogen-cracking gas. The normally high nitrogen content (18.05%–40.92%) is attributed to organic matter cracking and thermal ammoniation in the high-maturity stage. Specifically, the high heat flow effect of the Emeishan mantle plume exacerbates the thermal cracking of organic matter in the Longmaxi Formation shale, accompanied by nitrogen generation. In comparison, the abnormally high nitrogen content (86.79%–98.54%) is ascribed to the communication between the atmosphere and deep underground fluids by deep faults, which results in hydrocarbon loss and nitrogen intrusion, acting as the key factor for deconstruction of the primary shale gas reservoir. Results of this study not only enrich research on genetic mechanism of high-maturity N2 shale gas reservoirs, but also provide theoretical guidance for subsequent gas reservoir resource evaluation and well-drilling deployment in this area. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the prevalence and transmission of mcr-3 among Salmonella enterica serotype Typhimurium and 1,4,[5],12:i:-.Methods: A total of 4724 clinical Salmonella isolates were screened for the presence of mcr-3 in China during 2014-19. The clonal relationship of the mcr-3-positive isolates and their plasmid contents and complete sequence were also characterized based on WGS data from the Illumina and MinION platforms.Results: We identified 10 mcr-3-positive isolates, and all were MDR, mostly resistant to colistin, cefotaxime, ciprofloxacin, doxycycline and florfenicol. mcr-3 was co-present with blaCTX-M-55-qnrS1 on hybrid ST3-IncC-FII conjugatable plasmids (n = 6) and an ST3-IncC non-conjugatable plasmid (n = 1) and embedded into a pCHL5009T-like IncFII plasmid on the Salmonella chromosome (n = 3). Four distinctive genetic contexts surrounded mcr-3 and all but one were closely related to each other and to the corresponding region of IncFII plasmid pCHL5009T. IS15DI was most likely the vehicle for integration of mcr-3-carrying IncFII plasmids into ST3-IncC plasmids and the chromosome and for shaping the MDR regions. In addition, a phylogenetic tree based on the core genome revealed a unique Salmonella lineage (≤665 SNPs) that contained these 10 mcr-3-positive isolates and another 38 (33 from patients) mcr-3-positive Salmonella from five countries. In particular, most of the 51 mcr-3-positive isolates belonged to ST34 and harboured diverse antibiotic resistance genes (ARGs), including mcr-3-blaCTX-M-55-qnrS1, and possessed similar ARG profiles.Conclusions: Our findings revealed global clonal spread of MDR ST34 Salmonella from clinical isolates co-harbouring mcr-3 with blaCTX-M-55 and qnrS1 and a flexibility of mcr-3 co-transmittance with other ARGs mediated by mobile genetic elements. [ABSTRACT FROM AUTHOR]

Virginiamycin (VM), a streptogramin antibiotic, has been used to promote healthy growth and treat illnesses in farm animals in the United States and other countries. The combination streptogramin Quinupristin‐Dalfopristin (QD) was approved in the United States in 1999 for treating patients with vancomycin‐resistant Enterococcus faecium (VREF) infections. Many chickens and swine test positive for QD‐resistant E. faecium, raising concerns that using VM in food animals might select for streptogramin‐resistant strains of E. faecium that could compromise QD effectiveness in treating human VREF infections. Such concerns have prompted bans and phase‐outs of VM as growth promoters in the United States and Europe. This study quantitatively estimates potential human health risks from QD‐resistant VREF infections due to VM use in food animals in China. Plausible conservative (risk‐maximizing) quantitative risk estimates are derived for future uses, assuming 100% resistance to linezolid and daptomycin and 100% prescription rate of QD to high‐level (VanA) VREF‐infected patients. Up to one shortened life every few decades to every few thousand years might occur in China from VM use in animals, although the most likely risk is zero (e.g., if resistance is not transferred from bacteria in food animals to bacteria infecting human patients). Sensitivity and probabilistic uncertainty analyses suggest that this conclusion is robust to several data gaps and uncertainties. Potential future human health risks from VM use in animals in China appear to be small or zero, even if QD is eventually approved for use in human patients. [ABSTRACT FROM AUTHOR]

Copyright of Hydrogeology Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To investigate the mechanism of the organic‐matter enrichment in the Lower Longmaxi Formation shale, the geochemistry and total organic carbon (TOC) of the Longmaxi Formation black shales in the Jiaoshiba, Zhaotong, and Weiyuan areas of the Sichuan Basin were analyzed. Paleoproductivity proxy parameters (Babio, Siex, and Ni/Al), clastic influx proxies (TiO2 and Ti/Al), redox indices (V/Cr, Ni/Co, V/(V+Ni), and U/Th), and hydrothermal indicators (Fe, Mn, and Y concentrations; Fe/Ti ratio and a Ni‐Zn‐Co diagram) were employed to decipher the paleoenvironment of the Lower Longmaxi Formation shales. TiO2 and Ti/Al indicated low terrigenous detrital influx in all three areas. However, Babio, Siex, and Ni/Al indicated high productivity in the Jiaoshiba area. V/Cr, Ni/Co, and U/Th indicated higher oxygen content with larger fluctuations in the Zhaotong and Weiyuan areas. Fe, Mn, and Y concentrations and the Fe/Ti ratio implied greater active hydrothermal activity in the Weiyuan area. These heterogeneities were considered to be closely related to the paleoenvironment and paleogeography, and the large basement faults that developed during the Chuanzhong paleo‐uplift could have provided vents for deep‐hydrothermal‐fluid upwelling. The redox indices (V/Cr, Ni/Co, and U/Th) and a paleoproductivity proxy (Ni/Al) displayed a significant correlation with the TOC, suggesting that both excellent preservation conditions and high paleoproductivity were the controlling factors for the enrichment of organic matter in the Longmaxi Formation shale. There was no obvious correlation between the clastic influx proxy (Ti/Al) and the TOC due to the extremely low supply of terrigenous debris. The hydrothermal indicator (Fe/Ti) was negatively correlated with the TOC in the Weiyuan area, indicating that hydrothermal activity may have played a negative role in the accumulation of organic matter. This study suggests that the enrichment of organic matter in the Longmaxi Formation marine shale varied according to the paleogeography and sedimentary environment. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the prevalence and transmission of 16S rRNA methylase genes among Salmonella isolates from food animals in China.Methods: A total of 310 Salmonella isolates collected from food animals in seven provinces of China during 2016-17 were screened for 16S RMTase genes. The clonal relationship of the 16S RMTase-producing isolates and their plasmid contents were also characterized.Results: rmtB and armA were respectively identified in 12 and 1 Salmonella enterica serovar Indiana (Salmonella Indiana) isolates from farmed ducks. These 13 isolates concurrently expressed high-level resistance to amikacin, cefotaxime and ciprofloxacin. They were assigned to seven distinct PFGE patterns and the high similarity among 10 of the 12 rmtB-carrying isolates suggests clonal expansion. The rmtB gene was co-transferred with blaCTX-M-27-qepA and qepA in eight and two of the isolates, respectively, and was located on F2:A1:B1 plasmids with sizes of 135 and 100 kb, respectively. These 10 rmtB-bearing plasmids showed four restriction patterns with a high similarity. Four representative rmtB-bearing plasmids were fully sequenced and they exhibited remarkable similarity and possessed typical FII backbones. The primary differences were located in the region between blaTEM-1 and ycgA. Furthermore, a novel MDR region (13.5 kb) was identified that contained qepA, rmtB and blaCTX-M-27.Conclusions: This is the first report, to our knowledge, of the prevalence and complete sequences of plasmids simultaneously containing rmtB, qepA and blaCTX-M-27. These findings underscore a major public health threat posed by epidemic F2:A1:B1 plasmids bearing qepA-rmtB-blaCTX-M-27 that are circulating in XDR Salmonella Indiana clonal isolates from waterfowl husbandry. [ABSTRACT FROM AUTHOR]

Abstract The cfr gene associated with linezolid resistance has attracted wide attention. However, little is known about its prevalence and mode of transmission in Enterococcus faecalis. In this study, we investigate the prevalence and genetic environment of the cfr gene in 91 E. faecalis isolates collected from swine faecal swabs in 30 farms in Guangdong Province, China in 2012. A relatively high prevalence of cfr was identified in E. faecalis isolates (11/91, 12.1%) by PCR. All the cfr- positive E. faecalis strains had a multidrug-resistance phenotype including erythrocin, tetracycline, gentamicin, kanamicin and ciprofloxacin, except vancomycin and linezolid. Molecular typing indicated that ST475 and ST16 were the most common types in cfr- positive E. faecalis strains. In addition, we demonstrated that all the cfr genes were located on plasmids by S1 -PFGE and Southern blotting. A 12 kb cfr- positive plasmid (pE30) was identified in most (9/11) E. faecalis strains, but it couldn't mediate resistance to linezolid in the transconjugant. Sequence analysis showed that the pE30 was a pCPPF5-like plasmid and the region surrounding the cfr gene was the same as a cfr -carrying IS Enfa5 -composite element in Streptococcus plasmid pStrcfr with 4 bp direct repeat (GTAT) on both sides. In conclusion, the cfr gene which had no linezolid resistance phenotype was present in multidrug-resistance E. faecalis strains, and the clonal spread of ST475 and ST16 strains and the horizontal transfer of the pCPPF5-like plasmids have contributed to the dissemination of cfr. Highlights • A relatively high prevalence of cfr was found in E. faecalis isolates from swine in China. • A prevent cfr -carrying pCPPF5-like plasmids was found and it contributed to 'non-linezolid resistance' phenotype in E. faecalis isolates. [ABSTRACT FROM AUTHOR]

Hydrogeochemical analysis and multivariate statistics were applied to identify flow patterns and major processes controlling the hydrogeochemistry of groundwater in the Jianghan Plain, which is located in central Yangtze River Basin (central China) and characterized by intensive surface-water/groundwater interaction. Although HCO3-Ca-(Mg) type water predominated in the study area, the 457 (21 surface water and 436 groundwater) samples were effectively classified into five clusters by hierarchical cluster analysis. The hydrochemical variations among these clusters were governed by three factors from factor analysis. Major components (e.g., Ca, Mg and HCO3) in surface water and groundwater originated from carbonate and silicate weathering (factor 1). Redox conditions (factor 2) influenced the geogenic Fe and As contamination in shallow confined groundwater. Anthropogenic activities (factor 3) primarily caused high levels of Cl and SO4 in surface water and phreatic groundwater. Furthermore, the factor score 1 of samples in the shallow confined aquifer gradually increased along the flow paths. This study demonstrates that enhanced information on hydrochemistry in complex groundwater flow systems, by multivariate statistical methods, improves the understanding of groundwater flow and hydrogeochemical evolution due to natural and anthropogenic impacts. [ABSTRACT FROM AUTHOR]

Copyright of Hydrogeology Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

High-salinity paleowater from low-permeability aquitards in coastal areas can be a major threat to groundwater resources; however, such water has rarely been studied. The chemical and isotopic compositions of porewater extracted from a 200-m-thick Quaternary sedimentary sequence in the western coastal plain of Bohai Bay, China, were analyzed to investigate the salinity origin and chemical evolution of porewater in aquitards. Porewater samples derived at depths shallower than 32 m are characterized by Cl-Na type saline water (total dissolved solids [TDS], 10.9-84.3 g/L), whereas those at depths greater than 32 m comprise Cl·SO4-Na type brackish water (TDS, 2.2-6.3 g/L). Saline porewater is interpreted as evaporated seawater prior to halite saturation, as evidenced by Cl-Br relationships. Although substantial dilution of saline porewater with meteoric water is supported by a wider Cl− range and δ2H-δ18O covariance, the original marine waters were not completely flushed out. The deeper brackish porewater is determined to be a mixture of fresher porewater and brine groundwater and had a component of old brine of less than 10%, as indicated by a mixing model defined using δ2H and Cl− tracers. Porewater δ2H-δ18O relationships and negative deuterium excess ranging from −25.9‰ to −2.9‰ indicate the existence of an arid climate since Late Pleistocene in Tianjin Plain. The aquitard porewaters were chemically modified through water-rock interactions due to the long residence time. [ABSTRACT FROM AUTHOR]

We developed a clay pore water (CPW) isotopic method for tracing paleoenvironments characterized by sporopollens. The thick clayey layers have the advantage of preserving pore water regardless of whether the water is inherent in the clayey layers or not. Therefore, the clayey layers are a suitable target from which paleoenvironmental information can be extracted. Sediment sporopollens as well as CPW deuterium and oxygen isotopes were investigated in drilling cores obtained from a 130-m borehole at a field site in Hengshui in the North China Plain. Our interpretation of δ 18 O in CPW was consistent with sporopollens climate indices, indicating that CPW was an effective proxy for obtaining paleoenvironmental information. Sporopollens species were abundant in the cores, but the quantity of each species was low. Furthermore, mean annual temperature and precipitation curves were established using a pollen–climatic response surface model. The results indicated two warm-humid periods (5.2–0 m, 22.6–11 m) and one cold-dry period (8.8–6.4 m) in the Holocene as well as two warm-humid periods (90.6–83 m, 110.6–108.2 m) and three cold-dry periods (approximately 40 m, 66.4–56.8 m, approximately 100 m) in the Late Pleistocene. Data derived from the sporopollens and CPW cumulatively elucidate the environmental change in Northern China. [ABSTRACT FROM AUTHOR]

Using the model and quantitative parameters of contrast-enhanced ultrasound (CEUS) to assess the severity of secondary hyperparathyroidism (SHPT) was proposed. 42 SHPT patients who underwent CEUS examination were divided into three groups, light, moderate, and heavy as per parathyroid hormone (PTH). The process of CEUS was divided into two phases, wash-in phase and wash-out phase. The three groups were analyzed with their enhancing model in the two phases. The quantitative parameters of CEUS such as Arrival Time (AT), Time to Peak (TTP), Mean Transit Time (MTT), and Maximum Intensity (IMAX) were measured by time-intensity curve (TIC) and compared among the three groups. The enhancing model of light SHPT, moderate SHPT, and heavy SHPT showed statistical significance in wash-in phase and wash-out phase (P<0.05). No difference was observed in AT and TTP among the three groups (P>0.05) while MTT and IMAX showed statistical significance (P<0.05). The CEUS of light SHPT was characterized by “slow-in, fast-out, and lower-enhancement” with short enhancement time; the CEUS of moderate SHPT was characterized by “fast-in, fast-out, and higher-enhancement” with slightly long enhancement time; the CEUS of heavy SHPT was characterized by “fast-in, slow-out, and higher-enhancement” with long enhancement time. Therefore, the model and quantitative parameters of CEUS can be benefit for the assessment of the severity of SHPT. [ABSTRACT FROM AUTHOR]

Karstification degree is a key factor in controlling the characteristics of karst GFP. In this study, hydrogeology, karst development, hydrograph, artificial and natural tracers and hydrochemistry were integrated to characterize the groundwater flow patterns (GFP) in the Cambrian-Ordovician karst aquifer in Xiangxi River Basin. Groundwater samples were collected from three karst groundwater points: Wulongdong spring (WLD), Shuimoxi spring (SMX), and groundwater exposed by Borehole ZK03 (ZK03), which have different discharge variations. The hydrogeological analysis and the artificial tracer tests showed that groundwater runoff channel for WLD, SMX and ZK03 are dominated by conduits, fracture networks and micro fissures-matrix, respectively. The natural responses (discharge, electrical conductivity and temperature) of WLD to rainfall indicated that flow in this system is discharged by conduit, fracture and matrix, respectively. Stable isotopes (2H, 18O) of precipitation and groundwater suggested that the WLD and SMX recharge at the adjacent zone with mean elevations of 878 m and 676 m, respectively; while ZK03 recharge at mean elevations of 1338 m from thousands of meters away. Mean residence times calculated by artificial and natural tracers (18O, CFC) of conduit flow in WLD (7–19 h), fracture flow in WLD and SMX (243 and 600 days), and matrix flow in ZK03 (41 years) were obviously increased gradually. Hydro-chemical analysis shows that ZK03 has higher concentrations of ions that related to carbonate dissolution, indicating groundwater in ZK03 has longer time to interact with rocks. The results show that GFP in study aquifer are characterized by local fast conduit flow, local intermediate fracture networks flow and regional slow matrix flow with progressively slower groundwater refresh rate. The conceptual model was also proposed to enable a better understanding of groundwater circulation, water resources and vulnerability of the karst system in Central China. • The hierarchical karst flow systems in Central China have been researched. • Several methods have been used to identify karst groundwater flow systems. • Several characterizes indicating groundwater refresh rate have been researched. • A conceptual model of karst groundwater flow patterns has been proposed. [ABSTRACT FROM AUTHOR]

The analysis of educts has become an important aspect for the security evaluation of hydraulic construction. Brown, white-based colloidal educts appeared in the left drainage corridors of the dam over the Yangtze River after its 5-year operation, which did not happen in the initial investigation. In this article, the physics characteristics of the educts were affirmed, and the analysis results of the major and trace elements among educts and the corresponding location of water samples, core samples, indicate that educts are the products from the chemical potential erosion of the dam foundation rock. Brown educts are uncertainties Fe and Mn-based materials, mainly derived from the corrosion of the chlorite and biotite, which may be caused by the changes of the oxidizing condition. White educts mainly with Si and Ca are derived from the corrosion of the calcite, feldspar, and partly invalidation of foundation curtain. Additionally, similarities of the chondrite normalized rare earth element (REE) patterns between educts and bedrock further illustrate homologous, and Ce and Eu anomalies relative to chondrite reflect changes of the water environment condition. [ABSTRACT FROM AUTHOR]

Summary: In recent years, facing serious global competition, the Chinese government has focused on accelerating the growth of the advanced technology sector including nanotechnology in order to lift the country''s status from manufacturing raw materials and goods up to innovation technology, information economy and green efficient energy. With trillions in tangible monetary reserves, the government has substantially increased its investment in nanotechnology through several major initiatives. These measures comprise tax incentives and low rents for new facilities within economic development parks to stimulate the growth of new nanotechnology-related companies and attract foreign investment. This article outlines some of the current nanotechnology businesses, programs and markets across China, including its technology focus, collaborations, geography, and funding from central and local governments and from the private sector. Efforts are being made in China to increase the number and quality of nanotechnology-related publications and patents, and to pursue industrial-scale production of nanomaterials with the intention of opening up opportunities for new businesses to sprout and grow. Watching China''s shift to a nation that promotes innovation will be an exciting time for the global nanotechnology community. It is hoped that R&D and commercial applications of nanomaterials and nanotechnology will provide new impetus for faltering economies. [Copyright &y& Elsevier]

Background: Staphylococcus aureus, particularly methicillin-resistant S. aureus (MRSA), is an important cause of pyogenic skin and soft tissue infections (SSTIs). The aim of present study is to investigate the molecular characteristic of Staphylococcus aureus isolates isolated from the pus samples from the patients with purulent skin and soft tissue infections in Wenzhou, China. Methods: Between December 2002 and June 2008, a total of 111 nonduplicate S. aureus isolates were collected from the pus samples of the patients with SSTIs in a teaching hospital in Wenzhou, China. All the tested isolates were confirmed as S. aureus using a Staph SPA agglutination kit, Gram's stain and a Vitek-60 microbiology analyzer. The homology among the tested isolates was determined by pulsed-field gel electrophoresis (PFGE). Multilocus sequence typing (MLST) was used to determine the sequence types (STs) of the selected isolates. The genotypes of SCCmec were determined by a multiplex PCR in the MRSA isolates. Panton-Valentine leukocidin (PVL) genes and mecA were also determined by another multiplex PCR. Results: Among the 111 S. aureus isolates, 48 and 63 isolates were community-acquired and hospital-acquired respectively. Sixty isolates were confirmed as MRSA harboring mecA detected by PCR. A total of 32 PFGE clonal types were obtained by PFGE, with 10 predominant patterns (types A to J). Twenty-five different STs including ST398 and three novel STs were found among 51 selected isolates. The main STs were ST239, ST1018, ST59, ST7 and ST88. Of 60 MRSA isolates, SCCmec II, III, IV and SCCmec V were found in three, 50, three and two isolates, respectively. The positive rates of PVL genes in overall isolates, HA-isolates, CA-isolates, MRSA isolates and MSSA isolates were 23.4% (26/111), 20.6% (13/63), 27.1% (13/48), 21.7% (13/60) and 25.5% (13/51), respectively. Eight (33.3%, 8/24) of 24 CA-MRSA isolates and 5 (13.9%, 5/36) of 36 HA-MRSA isolates were positive for PVL genes. ST239-MRSA-SCCmecIII and ST1018-MRSASCCmecIII clones were found to be main clones and spread between community and hospital. Conclusion: S. aureus isolates causing SSTIs showed considerable molecular heterogeneity and harbored high prevalence of PVL genes. Clonal spread was responsible for the dissemination of the isolates of S. aureus associated with SSTIs. [ABSTRACT FROM AUTHOR]

• Hydraulic conductivity tensors were used to represent the potential of karst development. • A toolbox was developed to simulate flow through dense fracture networks. • A toolbox was developed to calculate hydraulic conductivity tensors. • A new methodology was proposed to generate plausible karst conduit networks. Karst aquifers are difficult to model due to their complex conduit networks that are heterogeneous and anisotropic. Here, we present a heuristic algorithm for modeling karst networks by calculating minimum-effort paths based on our knowledge of karst evolution that is constrained by field observations. The methodology consists of a) using discrete fracture network models along with fracture-parameter estimates (e.g., frequency, extent, spacing, and apertures) to equivalent porous media properties (e.g., size of the representative elementary volume, hydraulic conductivity tensor), b) rendering the velocity field using the tensor field coupled with the 3D regional hydrogeology that includes likely recharge and discharge locations, and c) generating karst conduits using the Anisotropic Fast Marching Algorithm (AFMA). This approach a) avoids the need to model discrete fractures by replacing them with a tensor that incorporates small-scale, dense and interconnected fractures, b) assumes that conduits follow the minimum-effort path from sinkholes toward springs, and c) efficiently accounts for regional hydrogeology, anisotropy, and regional flow conditions within 3D conduit networks. The application of the proposed approach in Wulongdong Basin in Hubei Province, China is taken as the demonstrate example. Compared to other techniques, this methodology substantially improves computational efficiency and reduces computer memory, thus providing a useful tool for generating ensembles of possible karstic conduit networks to analyze flow and transport prediction uncertainty associated with a lack of knowledge about network geometry. [ABSTRACT FROM AUTHOR]

This paper applies a conceptual framework, developed by Boisot (1986), to an analysis of the behaviour of Chinese enterprise managers. In a replication of Mintzberg's 1973 study of US managers, six Chinese enterprise directors were time studied over a period of six days, and the findings analyzed using the framework. It appears that although Chinese enterprise managers in the sample share many behavioural characteristics with their US counterparts, they do so in an institutional setting that places a different construction on their behaviour. In particular, the analysis suggests that the Chinese firm is not available to them as an extension of their managerial prerogative and, if anything, is institutionally designed to constrain it. In such a setting, opportunistic behaviour expresses a personal survival strategy rather than a quest for personal gain. [ABSTRACT FROM AUTHOR]

• Agricultural activities have changed groundwater flow patterns in Manas River Basin. • Local, intermediate and regional flow systems along with geochemistry are revealed. • Rainfall, surface water and irrigation water are all important recharge sources. • Groundwater pumping has caused mixing between younger and older groundwater. The impacts of long-term pumping on groundwater flow patterns and groundwater chemistry are unclear in the Manas River Basin, an arid inland basin in Northwest China. In this study, hydraulic heads, hydrochemistry and environmental isotopic tracers were analyzed to reveal groundwater flow patterns, recharge sources and deduce hydrogeochemical processes in this highly exploited aquifer system. Spatial trends in the isotopic ratios δ18O and δ2H indicate that groundwater originates from glacial melting and precipitation in the mountainous area. In the piedmont plains, dissolution of calcite, gypsum and dolomite yields a groundwater type dominated by Ca-HCO 3 -SO 4 with TDS of 300 mg/L. In this area, high 3H concentrations demarcate local flow systems and imply modern precipitation recharge. Downgradient in the lowlands, irrigation return flow recharges shallow groundwater through local flow paths. Groundwater pumping has intensified vertical hydraulic gradients causing vertical mixing between aquifers. Generally, across the basin, regional flow systems contain groundwater with 14C ages ranging from modern to 33,000 years, with the oldest waters found in wells with depths greater than 200 m. From high to low elevation groundwater chemistry transitions from Ca-HCO 3 -SO 4 to Na-Cl-SO 4 type as concentrations of Cl− and overall TDS increase. The replacement of Ca2+ with Na+ as the dominant cation suggests reverse ion exchange and carbonate precipitation occur along the intermediate and regional flow paths. Anthropogenic activities (i.e. pumping, irrigation return flow, application of fertilizers) impact shallow groundwater chemistry (<60 m). This research reveals the impacts of natural and human-induced hydrogeochemical processes impacting groundwater chemistry in this basin with implications for similar semi-arid to arid, inter-montane basins around the world. [ABSTRACT FROM AUTHOR]

The control of depositional conditions on sedimentary records spanning the Ordovician Wufeng–Silurian Longmaxi successions on the Yangtze Platform is not fully understood due to a lack of high-resolution faices analysis. This study aims to build a regional depositional model of this stratigraphic interval, to reveal the fundamental controls on the mineral assemblage and organic matter (OM) accumulation. Vertical lithofacies variability of two continuous cores in northwestern Guizhou area, south China, was analyzed at high resolution by RoqSCAN (an automated mineralogy tool) and field emission scanning electron microscope (FE-SEM) imaging. Based on multiscale sedimentary structure, mineral composition, total organic carbon (TOC) content, and geochemical characteristics, seven lithofacies were identified and interpreted as four facies associations (FA A-D) to characterize the spatio-temporal variation in these sedimentary environments. The deep-siliceous shelf FA-A is the richest in TOC content and biogenetic quartz, attributed to the strong anaerobic watermass, minimal terrestrial-flux, and enhanced organic-productivity during two global transgressions. The middle mixed shelf FA-B has moderate TOC and mixed minerals resulting from reworking processes during a fall of sea level caused by regional uplifts. Although the primary organic-productivity was promoted by increased volcanic ash fall, dilution due to increased terrestrial inputs made OM difficult to accumulate. The shallow muddy shelf FA-C and the shallow silty shelf FA-D were not favorable for OM accumulations because of the low organic productivity, strong oxygenated watermass, and high detrital dilution, through long-term sea level drops. The facies attributes of the target mudstones were remarkably influenced by regional tectonic-eustasy, in addition to global glacio-eustasy. • Mineralogy and organic matter of Wufeng-Longmaxi mudstones were characterized. • Lithofacies type and distribution were analyzed at high-resolution. • Mineral assemblage is controlled by depositional condition and diagenetic overprinting. • Organic matter accumulation is remarkably influenced by regional tectonic-eustasy. • A regional depositional model is proposed. [ABSTRACT FROM AUTHOR]

Background:The association of PMQR and ESBLs in negative-bacteria isolates has been of great concern. The present study was performed to investigate the prevalence of co-transferability of oqxAB and blaCTX-M genes among the 696 Escherichia coli (E. coli) isolates from food-producing animals in South China, and to characterize these plasmids. Methods:The ESBL-encoding genes (blaCTX-M, blaTEM and blaSHV), and PMQR (qnrA, qnrB, qnrS, qnrC, qnrD, aac(6’)-Ib-cr, qepA, and oqxAB) of these 696 isolates were determined by PCR and sequenced directionally. Conjugation, S1 nuclease pulsed-field gel electrophoresis (PFGE) and Southern blotting experiments were performed to investigate the co-transferability and location of oqxAB and blaCTX-M. The EcoRI digestion profiles of the plasmids with oqxAB-blaCTX-M were also analyzed. The clonal relatedness was investigated by PFGE. Results:Of the 696 isolates, 429 harbored at least one PMQR gene, with oqxAB (328) being the most common type; 191 carried blaCTX-M, with blaCTX-M-14 the most common. We observed a significant higher prevalence of blaCTX-M among the oqxAB-positive isolates (38.7%) than that (17.4%) in the oqxAB-negative isolates. Co-transferability of oqxAB and blaCTX-M was found in 18 of the 127 isolates carrying oqxAB-blaCTX-M. These two genes were located on the same plasmid in all the 18 isolates, with floR being on these plasmids in 13 isolates. The co-dissemination of these genes was mainly mediated by F33:A-: B- and HI2 plasmids with highly similar EcoRI digestion profiles. Diverse PFGE patterns indicated the high prevalence of oqxAB was not caused by clonal dissemination. Conclusion:blaCTX-M was highly prevalent among the oqxAB-positive isolates. The co-dissemination of oqxAB-blaCTX-M genes in E. coli isolates from food-producing animals is mediated mainly by similar F33:A-: B- and HI2 plasmids. This is the first report of the co-existence of oqxAB, blaCTX-M, and floR on the same plasmids in E. coli. [ABSTRACT FROM AUTHOR]

The deposition of black shales has been widely attributed to primary productivity, preservation controlled by redox conditions, and detrital dilution controlled by sedimentation rates. It is difficult to distinguish the relative importance of productivity and redox conditions in organic matter accumulation. On the Upper Ordovician-Lower Silurian Wufeng-Longmaxi black shales, we combined petrographic features, major and trace elemental proxies, and organic carbon isotopic analysis to determine the relative importance of productivity versus anoxia on organic matter accumulation and the evolution of factors controlling organic matter accumulation across the Ordovician-Silurian boundary in the Middle Yangtze region. Our research also sheds light on the temporal variations in redox conditions that caused the Late Ordovician mass extinction. Productivity, redox conditions, detrital dilution, and basin restriction changes over time as the Wufeng-Longmaxi Formations were deposited (from upper Katian to Rhuddanian stage). Based on the stratigraphic profiles of productivity (biogenic Si and P/Al), redox conditions (Mo/Al, U/Th ratios, and DOP T values), detrital fraction flux (Al 2 O 3), and the cross-plots of biogenic Si versus Co*Mn values, our findings indicate that organic matter accumulation was a combined effect of productivity and anoxia; however, the elevated productivity caused by upwelling that introduced plenty of nutrients to the oceans was the direct factor driving organic matter accumulation. Previous research found a simultaneous variation in stratigraphic profiles of productivity and redox proxies; however, in our datasets, we found an offset between productivity geochemical proxies (biogenic Si content) and redox conditions (Mo/Al). Biogenic Si profile peaks occur stratigraphically beneath Mo/Al profile peaks. Anoxia does not coexist with increased paleoproductivity across the Ordovician-Silurian boundary in the Middle Yangtze region, and redox conditions may be disrupted by local geological events. • Enhanced productivity was the direct factor driving organic matter accumulation. • Increased upwelling enhanced productivity by providing nutrients. • Enhanced productivity fails to simultaneously cause anoxic conditions. [ABSTRACT FROM AUTHOR]

• Holocene seawater was observed widespread along the coastline of eastern China. • Evolution of saline porewater is attributed to transgression and regression cycle. • Transport of porewater is controlled by diffusion in natural conditions. • Porewater salinity is impacted by advective flow in areas of extensive pumping. Aquitards can preserve paleo-saltwater and have a long and profound influence on the aquifer groundwater, yet they have received less attention. Here, five one-dimensional vertical profiles of the natural tracers, Cl−, Br−, δ2H, and δ18O of aquitard porewater were measured and combined with eight existing profiles collected from previous studies in three Eastern China coastal plains, Bohai bay, Laizhou bay, and Jiangsu coastal plain, to show the salinity origin and the timescale of the transport of porewater across aquitards since the mid-Holocene. Evidence of paleo-seawater impacted by Holocene transgression is noticed as peak Cl− concentration, enriched water isotopes, and lower Cl/Br ratios are observed in the porewater at about the bottom depth of Holocene of 25 m. The shape of Cl− profiles and associated 1-D transport models confirms Holocene seawater's presence in the sediment and the alternating transgression and regression control the salinity evolution of coastal aquitard porewater. Diffusion is the dominant transport across aquitard with an upward velocity between 0.03 and 0.6 mm/yr. Reverse advective flow has affected the solute transport in areas of extensive pumping. Anthropogenic activities enhance the leaching of salty porewater into aquifers in coastal areas, necessitating the need for research focused on marine aquitard salty water. [ABSTRACT FROM AUTHOR]

We investigated the prevalence and transmission of NDM-producing Enterobacteriaceae in fecal samples of geese and environmental samples from a goose farm in southern China. The samples were cultivated on MacConkey agar plates supplemented with meropenem. Individual colonies were examined for blaNDM, and blaNDM-positive bacteria were characterized based on whole-genome sequencing (WGS) data from the Illumina and Oxford Nanopore Technologies (ONT) platforms. Of 117 samples analyzed, the carriage rates for New Delhi metallo-b-lactamase (NDM)-positive Enterobacteriaceae were 47.1, 18, and 50% in geese, inanimate environments (sewage, soil, fodder, and dust), and mouse samples, respectively. Two variants (blaNDM-1 and blaNDM-5, in 4 and 40 isolates, respectively) were found among 44 blaNDM-positive Enterobacteriaceae; these variants belonged to eight species, and Escherichia coli was the most prevalent (50%). WGS analysis revealed that blaNDM coexisted with diverse antibiotic resistance genes (ARGs). Population structure analysis showed that most E. coli and Enterobacter sp. isolates were highly heterogeneous, while most Citrobacter sp. and P. stuartii isolates possessed extremely high genetic similarities. In addition, blaNDM-5-positive ST4358/ST48 E. coli isolates were found to be clonally spread between geese and the environment and were highly genetically similar to those reported from ducks, farm environments, and humans in China. Plasmid analysis indicated that IncX3 pHNYX644-1-like (n=40) and untypeable pM2-1-like plasmids (n = 4) mediated blaNDM spread. pM2-1-like plasmids possessed diverse ARGs, including blaNDM-1, the arsenical and mercury resistance operons, and the maltose operon. Our findings revealed that the goose farm is a reservoir for NDM-positive Enterobacteriaceae. The blaNDM contamination of wild mice and the novel pM2-1-like plasmid described here likely adds to the risk for dissemination of blaNDM and associated resistance genes. Carbapenem-resistant bacteria, in particular NDM-producing Enterobacteriaceae, have become a great threat to global public. These bacteria have been found not only in hospital and community environments but also among food animal production chains, which are recognized as reservoirs for NDM-producing Enterobacteriaceae. However, the dissemination of NDM-producing bacteria in waterfowl farms has been less well explored. Our study demonstrates that the horizontal spread of blaNDM-carrying plasmids and the partial clonal spread of blaNDM-positive Enterobacteriaceae contribute to the widespread contamination of blaNDM in the goose farm ecosystem, including mice. Furthermore, we found a novel and transferable blaNDM-1-carrying multidrug resistance (MDR) plasmid that possessed multiple environmental adaptation-related genes. The outcomes of this study contribute to a better understanding of the prevalence and transmission of blaNDM-carrying Enterobacteriaceae among diverse niches in the farm ecosystem. [ABSTRACT FROM AUTHOR]

• 90 operating highway tunnels with defects are analyzed. • Five characteristics of tunnel defects are studied. • A set of defect prevention and treatment process is proposed. • The preventive measures and treatment measures are listed and analyzed. The number and length of highways in China far exceed those in other countries. Therefore, to better understand the defects that have occurred in Chinese highways that are currently in service, we collected data on the defects in 90 such tunnels. Using these data, we conducted a systematic study on the causes of such defects. Based on the characteristics thus obtained, the defects could be divided into seven categories: structural deformation, structural damage, material deterioration, water leakage, frost damage, construction defects, and others (accessory facility defects). The results reveal that lining cracks and water leakage are the most common defects in the highway tunnels of China. These tunnel defects can be categorized based on their risk, correlations, visibility, regional characteristics, and progressive nature. Human activities are the primary cause of highway tunnel defects. The treatment measures for such tunnel defects in China can be categorized as additional, repair, and replacement measures; these measures are selected based on actual requirements of addressing the defects. Lastly, corresponding preventive measures and disposal procedures are established based on the abovementioned analyses. The results of this study are expected to serve as a reference and provide significant guidance for the prevention and treatment of road tunnel defects. [ABSTRACT FROM AUTHOR]

• Water-rock equilibria and local GW flow are partially mature in the basin. • Regional inter-aquifer flow and GW mixing are depicted in aquifer systems. • Silicate and carbonate GW mixing dominate hydrogeochemical process at basin scale. This study aims to identify water–rock interaction and groundwater flow processes in aquifer systems with contrasting mineralogy at the basin scale. Investigations have been carried out using major ion geochemistry and environmental isotopes (δ 2H and δ 18O of water, δ 13C values, 87Sr/86Sr ratios, and 14C activities) within aquifers with contrasting mineralogy in the Qingyi river basin (QRB, east China) composed of marine carbonate and continental granitic sediments with successive strata during Paleozoic, Mesozoic and Cenozoic. Analysis of 95 rain, surface and groundwater, and 12 solid rock samples found that dissolution of limestone, silicate minerals, and evapotranspiration dominated the hydrogeochemical process in the lower, upper, and middle basin, respectively. The various major ion and 87Sr/86Sr ratios of groundwater in each aquifer suggest that local lithology minerals dissolution controls the water–rock equilibria in the groundwater system. The 87Sr/86Sr ratios are correlated with both major ion geochemistry and δ 13C values, constraining the process of varying proportions of silicate and carbonate minerals dissolution. Percolating water from soils carrying dissolved CO 2 plays an important role in controlling the hydrogeochemical processes in the groundwater system throughout the QRB. Inter-aquifer flow has been proved by the well correlated relations between 87Sr/86Sr ratios and δ 13C values or/and Sr/Na and Ca/Na ratios, as well as the irregular groundwater apparent 14C ages (1.78 to 8.52 kyr) with respect to position in the basin. Admixture ratios of 9–50% are derived from the groundwater in limestone aquifer. The rapid decrease in carbonate groundwater mixing ratio is accompanied by an increase in 87Sr/86Sr ratios, indicating that groundwater is derived Sr from silicate weathering and abundant carbon from the soils. Regional inter-aquifer flow occurs in the buried carbonate aquifers based on isotopic evidence, which could result in karstic groundwater leakage in the Wuhu cityside and should be given special attention. [ABSTRACT FROM AUTHOR]

[Display omitted] • Water-level fluctuations strongly affect riparian N transformation and GHG emissions. • Drying and rewetting mediated by depth to water table enable aerobic nitrification. • The riparian zone is an important N 2 O source in the dry-to-wet transition season. • Soil PNR values near the river are highest in the dry-to-wet transition season. • Soil PDR values are as high or higher in the wet season than in the dry season. Greenhouse gas (GHG) emissions from riparian zones affect the global GHG balance, contribute to global warming and climate change, and generate adverse effects on ecological health as well as environmental, economic and social sustainable development. However, the influence of water-level fluctuations on depth-dependent soil properties, nitrogen transformation and GHG emissions in riparian zone ecosystems during wetting–drying cycles remains unclear. In this study, we analyzed seasonal nitrogen dynamics under seasonal water-level fluctuations at seven different depths (0–20, 20–40, 40–60, 60–80, 80–100, 100–120 and 120–140 cm) along a typical transect in the Jianghan Plain, Central China for 2018–2019. Changes in depth-dependent soil physical and chemical properties, soil textural characteristics and mineralogy, potential nitrification rate (PNR) and potential denitrification rate (PDR), as well as soil GHG emission rates were determined across a range of meteorological conditions and surface water and groundwater level fluctuations. Groundwater levels varied significantly between seasons with rising water-levels during the wet seasons and falling water-levels during the dry seasons. The physicochemical properties and chemical composition in the three studied riparian soil textures revealed higher spatiotemporal variability during the wet seasons as compared to the dry seasons. Our results showed that groundwater level depth was a crucial influencing factor controlling the microbial nitrogen transformation in the soil profiles. The PNR values were characterized by substantial seasonal variation with the same or higher metabolic activity in the dry season than in the wet season owing to water-level fluctuations, while they declined with depth. Compared to the wet season, the PDR values in the studied riparian zone were typically lower in the dry season due to extremely low soil water content constrained by fluctuating water-levels. Besides, the PDR values in the silt loam layers were higher than that in the sandy loam layer for most of the monitoring period. The depth-dependent GHG flux rates highlighted that the riparian zone ecosystem was a key source of CO 2 and N 2 O and a sink for CH 4. In summary, our findings suggest that fluctuating water table management in riparian ecosystems must be considered to more effectively control seasonal fluctuations of nitrogen dynamics and mitigate GHG emissions. Thus, a suitable riparian groundwater quality control and management scheme is urgently necessary to bring awareness of seasonal water-level fluctuations of riparian zones to catchment managers and policy makers. [ABSTRACT FROM AUTHOR]

• Land uses and redox conditions control nitrate behaviors in groundwater. • Atmospheric NO 3 − is a non-ignorable nitrate source of groundwater in subtropical basin. • Nitrification was effectively identified by negative correlation of δ15N-NH 4 + and δ15N-NO 3 −. • Groundwater flow system is a powerful tool to fuse multi-information for identifying nitrate sources. Land use patterns and regional hydrogeological conditions have a great impact on nitrate sources and transformation in groundwater at the large-basin scale. In this study, hydrochemistry, multiple isotopes (δD-H 2 O, δ18O-H 2 O, δ15N-NH 4 +, δ15N-NO 3 - and δ18O-NO 3 -), and a Bayesian model were integrated to identify nitrate sources and transformation in groundwater in the Qingyi River basin (QRB), a large subtropical basin in East China. Overall, increases in total dissolved solids, NO 3 -, and decreases in d-excess and dissolved oxygen concentrations were observed along the regional groundwater flow direction, suggesting groundwater in recharge and transition areas had fewer anthropogenic N inputs, shorter residence times, and more oxidizing environments. As demonstrated by the negative correlation of δ15N-NH 4 + and δ15N-NO 3 -, nitrification was dominant in recharge and transition areas, and δ18O-NO 3 - values above theoretical nitrification line indicated a mixing of atmospheric NO 3 - and nitrified NO 3 -. By contrast, denitrification was a major transformation in discharge areas. In recharge areas (with an area of 95.9% forest), soil organic nitrogen and atmospheric precipitation contributed 82.7% and 17.3%, respectively. In transition areas (54.3% forest, 42.5% farmland), the major nitrate sources were soil organic nitrogen (38.7%) and chemical fertilizer (27.7%). In discharge areas (52.4% farmland, 15.0% residential area), manure/sewage and soil organic nitrogen accounted for 34.6% and 28.4% of total nitrate. High soil organic nitrogen contribution in the QRB suggested land use in recharge areas is essential for controlling the groundwater nitrate contamination in basins. Finally, we proposed a conceptual model of the nitrate sources and transformation in groundwater in the QRB, revealing the nitrate behaviors in groundwater in a large basin within a framework of groundwater flow systems. This study proves that groundwater flow system is effective to fuse multi-information to identify nitrate sources and fate in groundwater in a large basin, which is helpful to regional groundwater management and protection in similar subtropical basins. [ABSTRACT FROM AUTHOR]

• 55 pumping tests were analyzed in the Jianghan Plain, Central China. • Aquifer parameters were obtained by different methods. • Spatial variability of hydraulic conductivity (K) was analyzed. • Main factors controlling the spatial variability of hydraulic conductivity (K) were discussed. In recent times, the groundwater in Jianghan Plain, Central China has come under severe stress from agricultural and industrial demand. The spatial variability of hydraulic conductivity (K) in the region is important for better and sustainable groundwater exploration and management. In this study, we determined the spatial distribution of K using a multi-method approach, i.e. analytic and numerical simulation as well as intelligent optimization methods (particle swarm optimization (PSO) and differential evolution (DE)) and geostatistics. Data from 55 multi-format pumping tests situated across the middle-confined aquifer (consisting of late Pleistocene (Qp 3 s) and middle Pleistocene (Qp 2 j)) were used. Results showed that for transient pumping test with constant rate by multi-wells, PSO and DE were faster and more precise, especially DE. For transient pumping test with variable rate as well as transient pumping test with constant rate by single well, the numerical method fitted the drawdown better, while the PSO and DE had large deviations at the early stage of pumping. Overall, the values of K vary from 0.032 to 10.64 m/d within Qp 3 s and 0.33 to 36.24 m/d within Qp 2 j. The spatial variability model demonstrated that the K values in Qp 3 s are greater than those in Qp 2 j. The heterogeneity elucidates the sedimentary development of the basin. These methods and results can provide new insights for estimating the spatial distribution of K for regional groundwater resources assessment in similar sedimentary environments around the world. [ABSTRACT FROM AUTHOR]

• A single chicken could harbour up to three different bacterial species carrying the mcr-1 gene. • Whole-genome sequencing revealed high heterogeneity of mcr-1 -positive Escherichia coli isolates within a single host. • Within the same chicken, the mcr-1 gene could be carried by plasmids belonging to five different Inc types. • Great diversity was also observed in the eight IncI2 plasmids bearing the mcr-1 gene within a single chicken. • A novel IS Apl1 -mediated complex transposition was identified in E. coli. To characterize the colistin-resistant bacterial population in the gut and assess diversity of mcr-1 transmission within a single individual. Large numbers of isolates (>100 colonies/chicken cecum sample) were collected from nine randomly selected mcr-1 -positive chickens in China and used for comprehensive microbiological, molecular and comparative genomics analyses. Of 1273 colonies, 968 were mcr-1 positive (962 Escherichia coli , two Escherichia fergusonii , two Klebsiella pneumoniae and two Klebsiella quasipneumoniae). One to six colistin-resistant species and three to 10 E. coli pulsed-field gel electrophoresis (PFGE) clusters could be identified from each sample. Whole-genome sequencing (WGS) analysis of the representative E. coli strains revealed three to nine sequence types observed in a single chicken host. The mcr-1 genes are located in either chromosomes or plasmids of different types, including IncI2 (n =30), IncHI2 (n =14), IncX4 (n =4), p0111(n =2) and IncHI1(n =1). Strikingly, in single cecum samples, one to five Inc type plasmids harbouring mcr-1 could be identified. Great diversity was also observed for the same IncI2 plasmid within a single chicken host. In addition, up to eight genetic contexts of the mcr-1 gene occurred within a single chicken. There is extensive heterogeneity and flexibility of mcr-1 transmission in chicken gut due to bacterial species differences, distant clonal relatedness of isolates, many types and variations of mcr -positive plasmids, and the flexible genetic context of the mcr - 1 gene. These compelling findings indicate that the gut is a 'melting pot' for active horizontal transfer of the mcr-1 gene. [ABSTRACT FROM AUTHOR]

Intestinal pathogenic Escherichia coli (InPEC) is one of the most common causes of bacterial diarrhea in farm animals, including profuse neonatal diarrhea and post weaning diarrhea (PWD) in piglets. In this study, we investigated the prevalence of InPEC and associated primary virulence factors among 543 non-duplicate E. coli isolates from diarrheal pigs from 15 swine farms in southern China. Six major virulence genes associated with InPEC were identified among 69 (12.71 %) E. coli isolates and included est (6.62 %), K88 (4.79 %), elt (3.68 %), eae (1.47 %), stx2 (0.92 %) and F18 (0.55 %). Three pathotypes of InPEC were identified including ETEC (8.10 %), EPEC (1.29 %) and STEC/ETEC (0.92 %). In particular, K88 was only found in ETEC from breeding farms, whereas F18 was only present in STEC/ETEC hybrid from finishing farms. Whole genome sequence analysis of 37 E. coli isolates revealed that InPEC strains frequently co-carried multiple antibiotic resistance gene (ARG). est, elt and F18 were also found to co-locate with ARGs on a single IncFIB/IncFII plasmid. InPEC isolates from different pathotypes also possessed different profiles of virulence genes and antimicrobial resistance genes. Population structure analysis demonstrated that InPEC isolates from different pathotypes were highly heterogeneous whereas those of the same pathotype were extremely similar. Plasmid analysis revealed that K88 and/or est/elt were found on pGX18-2-like/pGX203-2-like and pGX203-1-like IncFII plasmids, while F18 and elt/est, as well as diverse ARGs were found to co-locate on IncFII/IncFIB plasmids with a non-typical backbone. Moreover, these key virulence genes were flanked by or adjacent to IS elements. Our findings indicated that both clonal expansion and horizontal spread of epidemic IncFII plasmids contributed to the prevalence of InPEC and the specific virulence genes (F4, F18, elt and est) in the tested swine farms., Competing Interests: Declaration of Competing Interest We declare that we have no conflict of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Salmonella 4,[5],12:i:-, a monophasic variant of Salmonella Typhimurium, has emerged as a global cause of multidrug-resistant salmonellosis and has become endemic in many developing and developed countries, especially in China. Here, we have sequenced 352 clinical isolates in Guangdong, China, during 2009-2019 and performed a large-scale collection of Salmonella 4,[5],12:i:- with whole genome sequencing (WGS) data across the globe, to better understand the population structure, antimicrobial resistance (AMR) genomic characterization, and transmission routes of Salmonella 4,[5],12:i:- across Guangdong. Salmonella 4,[5],12:i:- strains showed broad genetic diversity; Guangdong isolates were found to be widely distributed among the global lineages. Of note, we identified the formation of a novel Guangdong clade (Bayesian analysis of population structure lineage 1 [BAPS1]) genetically diversified from the global isolates and likely emerged around 1990s. BAPS1 exhibits unique genomic features, including large pan-genome, decreased ciprofloxacin susceptibility due to mutation in gyrA and carriage of plasmid-mediated quinolone resistance (PMQR) genes, and the multidrug-resistant IncHI2 plasmid. Furthermore, high genetic similarity was found between strains collected from Guangdong, Europe, and North America, indicating the association with multiple introductions from overseas. These results suggested that global dissemination and local clonal expansion simultaneously occurred in Guangdong, China, and horizontally acquired resistance to first-line and last-line antimicrobials at local level, underlying emergences of extensive drug and pan-drug resistance. Our findings have increased the knowledge of global and local epidemics of Salmonella 4,[5],12:i:- in Guangdong, China, and provided a comprehensive baseline data set essential for future molecular surveillance.IMPORTANCE Salmonella 4,[5],12:i:- has been regarded as the predominant pandemic serotype causing diarrheal diseases globally, while multidrug resistance (MDR) constitutes great public health concerns. This study provided a detailed and comprehensive genome-scale analysis of this important Salmonella serovar in the past decade in Guangdong, China. Our results revealed the complexity of two distinct transmission modes, namely global transmission and local expansion, circulating in Guangdong over a decade. Using phylogeography models, the origin of Salmonella 4,[5],12:i:- was predicted from two aspects, year and country, that is, Salmonella 4,[5],12:i:- emerged in 1983, and was introduced from the UK, and subsequently differentiated into the local endemic lineage circa 1991. Additionally, based on the pan-genome analysis, it was found that the gene accumulation rate in local endemic BAPS 1 lineage was higher than in other lineages, and the horizontal transmission of MDR IncHI2 plasmid associated with high resistance played a major role, which showed the potential threat to public health., Competing Interests: The authors declare no conflict of interest.

The banning of colistin as a feed additive for food-producing animals in mainland China in 2017 caused the decline in the prevalence of Escherichia coli-mobilized colistin resistance ( mcr-1 ) in China. Salmonella Typhimurium and its monophasic 1,4,[5],12:i:- variants are also the main species associated with the spread of mcr-1 ; however, the evidence of the prevalence and transmission of mcr-1 among Salmonella is lacking. Herein, the 5,354 Salmonella isolates recovered from fecal samples of diarrheal patients in Guangdong, Southern China, from 2009 to 2019 were screened for colistin resistance and mcr-1 , and mcr-1 -positive isolates were characterized based on whole-genome sequencing (WGS) data. Relatively high prevalence rates of colistin resistance and mcr-1 (4.05%/4.50%) were identified, and more importantly, the prevalence trends of colistin-resistant and mcr-1 -positive Salmonella isolates had a similar dynamic profile, i.e., both were first detected in 2012 and rapidly increased during 2013 to 2016, followed by a sharp decrease since 2017. WGS and phylogenetic analysis indicate that, whether before or after the ban, the persistence and cross-hospital transmission of mcr-1 are primarily determined by IncHI2 plasmids with similar backbones and sequence type 34 (ST34) Salmonella in specific clades that are associated with a high prevalence of IncHI2 plasmids and clinically important antimicrobial resistance genes, including bla CTX-M-14 - fosA3-oqxAB - floR genotypes. Our work reveals the difference in the prevalence rate of mcr-1 in clinical Salmonella before and after the Chinese colistin ban, whereas mcr-1 transmission was closely linked to multidrug-resistant IncHI2 plasmid and ST34 Salmonella across diverse hospitals over 10 years. Continued surveillance is required to explore the factors related to a sharp decrease in mcr-1 after the recent ban and determine whether the ban has affected the carriage of mcr-1 in Salmonella circulating in the health care system. IMPORTANCE Colistin is one of the last-line antibiotics for the clinical treatment of Enterobacteriaceae . However, the emergence of the mobilized colistin resistance ( mcr-1 ) gene has spread throughout the entire human health system and largely threatens the usage of colistin in the clinical setting. In this study, we investigated the existence of mcr-1 in clinical Salmonella from a 10-year continuous surveillance and genomic study. Overall, the colistin resistance rate and mcr-1 carriage of Salmonella in tertiary hospitals in Guangdong (2009 to 2019) were relatively high and, importantly, rapidly increased from 2013 to 2016 and significantly decreased after the Chinese colistin withdrawal. However, before or after the ban, the MDR IncHI2 plasmid with a similar backbone and ST34 Salmonella were the main vectors involved in the spread of mcr-1 . Interestingly, these Chinese mcr-1 -carrying Salmonella obtain phylogenetically and phylogeographically distinct patterns compared with those from other continents and are frequently associated with clinically important ARGs including the extended-spectrum β-lactamases. Our data confirmed that the national stewardship intervention seems to be successful in blocking antibiotic resistance determinants and that continued surveillance of colistin resistance in clinical settings, farm animals, and related products is necessary.

As the strata sedimentary process proceeds, considerable amounts of nitrogen (N) is buried in sediments, which controls the sources and fate of N in the "groundwater-sediment" system. However, there is little concern regarding N burial characteristics in continuous sediment profiles from surface layer to deep aquifer thus far. In this study, lithology, grain size, geochronology, exchangeable N contents and geochemical proxies of sediments were analyzed to reveal the controlling mechanisms of N burial characteristics in Quaternary sediments and to interpret the enrichment of N in groundwater of central Yangtze River Basin. The results demonstrated a similar distribution trend for buried N in two sedimentary cores, which were high in the surface layer and decreased to stable in the deep aquifer. Excessive exchangeable N (EX-N) contents in sediments were mainly attributed to geologic origin. The N burial characteristics were controlled by the evolution of depositional environment: sedimentary facies determined the concentrations of total organic nitrogen (TON), further affecting the mineralization capacity of sediments; while paleoclimate regulated the intensity of the N transformation processes, ultimately influencing the actual concentrations of EX-N in sediments. In addition, due to the fast accumulation of alluvial deposits after Last Glacial Maximum and rapid development of Jianghan Lake Groups during Holocene, abundant organic matter (with high TON contents) was buried in sediments, which were still able to produce more ammonium or nitrate, and further posing continuous threats to groundwater quality. This study provided a new interpretation for the formation of high-ammonium aquifer in terms of depositional evolution., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Objective: To survey the status of iodine nutrition and the prevalence of thyroid diseases in Guangxi, China, and to explore the risk factors for positive thyroid antibody., Methods: We used the multistage stratified cluster random sampling method to select a total of 2488 subjects from an urban and a rural location. All the subjects completed a questionnaire survey, blood and urine samples were also collected, and B-mode thyroid ultrasound was used to determine thyroid function and detect thyroid antibodies., Results: 1) The median level of urinary iodine was 148.53 μg/L in school-age children in Guangxi, China. 2) The prevalence rates for thyroid diseases were as follows: hyperthyroidism, 0.89 %; subclinical hyperthyroidism, 1.05 %; hypothyroidism, 0.69 %; and subclinical hypothyroidism, 8.87 %. The rates of thyroid antibody positivity were as follows: thyroid peroxidase antibody (TPOAb), 13.60 %; thyroglobulin antibody (TGAb), 13.60 %; thyroid antibodies, 18.2 %; and thyroid nodules, 16.94 %. 3) The rate of TPOAb positivity was significantly higher in women aged 18-29, 30-39, 40-49, or 60-69 years than in men in the same age groups (P < 0.05), and the TGAb positivity rate was significantly higher in women than in men of the same age group (P < 0.05). 4) The rate of thyroid antibody positivity was significantly higher in individuals with iodine deficiency than in individuals with adequate iodine (21.6 % vs 18.4 %) or excess iodine (21.6 % vs 15.5 %) (both P < 0.05). 5) The female sex and a family history of thyroid diseases were the major risk factors for thyroid antibody positivity (odds ratio [OR] 3.010, P <0.05; OR 2.486, P <0.05)., Conclusion: The overall level of iodine is adequate in Guangxi, China; this level should be maintained to prevent the thyroid diseases related with iodine deficiency or excess of iodine. Female sex and a family history of thyroid diseases are independent risk factors for thyroid antibody positivity., (Copyright © 2021 Elsevier GmbH. All rights reserved.)

Excessive ammonia-nitrogen (N) in aquifers has caused groundwater pollution on the Dongting Plain (DTP), which seriously threatens the safety of drinking water. It is urgent and necessary to determine the sources and enrichment mechanisms of ammonia-N in groundwater. Carrying out water and soil collaborative research on a three-dimensional scale can more comprehensively analyze the sources of N, including natural and anthropogenic sources. In this study, surface and groundwater quality characteristics were examined from a total of 77 sites on the DTP. Two subsequent boreholes were drilled in the high ammonia concentration area and normal groundwater area, respectively, to compare the effects of anthropogenic activities. Indicators from hydrogeochemical and pedogeochemical analyses, as well as various isotopes, including δ 15 N-NH 4 + , δ 15 N-TON, δ 15 N-NO 3 - , δ 18 O-NO 3 - , δ 18 O-H 2 O, δD-H 2 O, and δ 13 C-TOC were used to identify ammonium sources and transformation mechanisms in the strata. We found that the sediments were contaminated by manure and sewage in the aquifers, and part of the shallow groundwater was additionally contaminated by nitrogen fertilizers. Excessive ammonium-N was also detected in the deep aquitards and sediments, which were mainly dominated by mineralization. Ammonia oxidation (with weak hydroxylamine oxidation) is an important biogeochemical process in which ammonia and nitrate do not accumulate in oxidizing groundwater environments. However, heterotrophic nitrification (HN) and anaerobic ammonium oxidation (ANAMMOX) are the release mechanisms for excessive ammonium-N under reducing conditions. In addition, organic matter (OM) on the DTP had a wide range of biogeochemical proxies generated by phytoplankton within a lake, and the comparatively resilient terrestrial organic residues washed in from the surrounding terrestrial area. This study breaks through the conventional mechanisms for the release of excessive ammonium from sediments to aquifers, which provides new ideas for research on ammonium in sediments and ammonia in groundwater., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: Serum biomarkers have been widely adopted in clinical practice for assisting lung cancer diagnoses, therapeutic monitoring, and prognostication. The function of a well-performing tumor biomarker depends on a reliable reference interval (RI) with consideration of the study subjects' age, gender, and geographical location. This study aimed to establish a RI for each of 6 lung cancer biomarkers for use in the whole country of China on Mindray platform., Methods: The levels of serum 6 lung cancer biomarkers-namely progastrin-releasing peptide (ProGRP), neuron-specific enolase (NSE), squamous cell carcinoma antigen (SCC), carcinoembryonic antigen (CEA), cytokeratin-19 fragment (CYFRA21-1), and human epididymis protein 4 (HE4)-were measured utilizing the chemiluminescence immunoassay on the Mindray CL-6000i platform following the laboratory standard operating procedures in apparently healthy Chinese individuals on large cohort, multicenter, and geographical consideration bases. The CLSI EP28-A3C guideline was followed for the enrollment of study subjects., Results: The age-stratified, gender-specific RIs for ProGRP, NSE, SCC, CEA, CYFRA21-1, and HE4 lung cancer biomarkers in the Chinese population have been established as described in the results and discussion in this work. In addition, various levels of the six lung cancer biomarkers among nine geographical locations in China have been observed., Conclusions: The sample volume of study cohort, age, and geographical location should be considered upon establishing a reliable biomarker RI. A RI for each of six lung cancer biomarkers has been established. The results from this study would be helpful for clinical laboratories in interpreting the analytical results and for clinicians in patient management., (© 2021 The Authors. Journal of Clinical Laboratory Analysis published by Wiley Periodicals LLC.)

Overuse of antibiotics in animal husbandry has led to an increase of antibiotic resistance microorganisms as well as antibiotic-resistance genes (ARGs). Duck farming in China is practiced on a large and diverse scale and the overuse of antibiotics in this field is gaining attention recently. We evaluated the diversity of ARGs from five duck farms using a functional metagenomic approach and constructed five libraries. A total of seventy-six resistant determinants were identified, of which sixty-one were gene variants or novel genes. The novel genes contained five β-lactamase-encoding genes designated as bla DWA1 , bla DWA2 , bla DWA3 , bla DWA4 and bla DWB1 , respectively, and two genes conferring resistance to fosfomycin designated as fosA-like1 and fosA-like2. Three of the five β-lactamase-encoding genes were further identified as extended-spectrum β-lactamases (ESBL) that can hydrolyze both penicillins and cephalosporins. Besides, two of the five β-lactamase-encoding genes were associated with mobile genetic elements, indicating a high potential for transfer of the genes to other bacterial hosts. The two novel fosA-like genes were able to increase the MICs of the test Escherichia coli strain from 2 μg/mL to as high as 256 μg/mL(up to 128-fold increase). Our study provides a reference for ARGs prevalence in duck farm wastes and implies that they are an important resistome reservoir, especially for novel ARGs with high spread potential., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

We investigated the prevalence and transmission of NDM-producing Enterobacteriaceae in fecal samples of geese and environmental samples from a goose farm in southern China. The samples were cultivated on MacConkey agar plates supplemented with meropenem. Individual colonies were examined for bla NDM , and bla NDM -positive bacteria were characterized based on whole-genome sequencing (WGS) data from the Illumina and Oxford Nanopore Technologies (ONT) platforms. Of 117 samples analyzed, the carriage rates for New Delhi metallo-β-lactamase (NDM)-positive Enterobacteriaceae were 47.1, 18, and 50% in geese, inanimate environments (sewage, soil, fodder, and dust), and mouse samples, respectively. Two variants ( bla NDM-1 and bla NDM-5 , in 4 and 40 isolates, respectively) were found among 44 bla NDM -positive Enterobacteriaceae ; these variants belonged to eight species, and Escherichia coli was the most prevalent (50%). WGS analysis revealed that bla NDM isolates were found to be clonally spread between geese and the environment and were highly genetically similar to those reported from ducks, farm environments, and humans in China. Plasmid analysis indicated that IncX3 pHNYX644-1-like ( E. coli and Enterobacter sp. isolates were highly heterogeneous, while most Citrobacter sp. and P. stuartii isolates possessed extremely high genetic similarities. In addition, bla NDM-5 -positive ST4358/ST48 E. coli isolates were found to be clonally spread between geese and the environment and were highly genetically similar to those reported from ducks, farm environments, and humans in China. Plasmid analysis indicated that IncX3 pHNYX644-1-like ( n  = 40) and untypeable pM2-1-like plasmids ( n  = 4) mediated bla NDM spread. pM2-1-like plasmids possessed diverse ARGs, including bla NDM-1 , the arsenical and mercury resistance operons, and the maltose operon. Our findings revealed that the goose farm is a reservoir for NDM-positive Enterobacteriaceae The bla NDM contamination of wild mice and the novel pM2-1-like plasmid described here likely adds to the risk for dissemination of bla NDM and associated resistance genes. IMPORTANCE Carbapenem-resistant bacteria, in particular NDM-producing Enterobacteriaceae , have become a great threat to global public. These bacteria have been found not only in hospital and community environments but also among food animal production chains, which are recognized as reservoirs for NDM-producing Enterobacteriaceae However, the dissemination of NDM-producing bacteria in waterfowl farms has been less well explored. Our study demonstrates that the horizontal spread of bla NDM -carrying plasmids and the partial clonal spread of bla NDM -positive Enterobacteriaceae contribute to the widespread contamination of bla NDM in the goose farm ecosystem, including mice. Furthermore, we found a novel and transferable bla NDM-1 -carrying multidrug resistance (MDR) plasmid that possessed multiple environmental adaptation-related genes. The outcomes of this study contribute to a better understanding of the prevalence and transmission of bla NDM -carrying Enterobacteriaceae among diverse niches in the farm ecosystem., (Copyright © 2021 American Society for Microbiology.)