Using DNA-based stable isotope probing (SIP) in microcosms, we demonstrate the shifts in active nitrifying communities in soil from field plots imposed by 8 years of mineral fertilizer N (NPK) or ...manure (M) applications compared with an unfertilized control (CK), and associated shifts in their temperature sensitivity. DNA-SIP indicates that ammonia-oxidizing archaea (AOA) were labeled to a much greater extent in the CK soil (74.6%) than in the NPK-amended (19.8%) or M-amended (27.1%) soils at 28 °C. In contrast, NPK soil showed the highest labeling of ammonia-oxidizing bacteria (AOB) (23.3%) relative to M (4.03%) and CK (2.42%) soils. This is further supported by significant decreases in the
13
C
-amoA
gene ratios of AOA/AOB in the NPK (4.14) and M (8.63) compared with CK (46.4) soils at 28 °C, while little difference was observed at 35 °C. The relative abundance of active AOA or AOB in the manure was between that in the CK and NPK soils. This may be attributable to the slower release of ammonium mineralized from manure than from urea. The active AOA in soil microcosms were dominated by
Nitrososphaera viennensis
-like groups regardless of fertilization history or temperature.
Nitrosomonas communis
-like AOB may be more adapted to the higher temperature than
Nitrosospira
cluster 3-like AOB. The labeling of nitrite oxidizers (nitrite-oxidizing bacteria) was lowest in NPK soil and was higher at 28 °C than 35 °C regardless of fertilization treatment. The finding indicates that intensified anthropogenic N inputs in the field may select for distinct active nitrifying communities that exhibited different temperature sensitivities.
This study conducted isothermal hot compression experiments on Incoloy825 superalloy, spanning temperatures from 1000 to 1150 °C, strain rates from 0.01 to 10 s−1, and a true strain of 0.69. ...Employing Electron Backscatter Diffraction and Transmission Electron Microscopy for characterization, the research systematically explored the alloy's thermal-mechanical behavior, hot processing maps, microstructural evolution, and dynamic recrystallization (DRX) mechanisms during hot deformation. True stress-strain curves were obtained for various deformation conditions, corrected, and used to establish a highly precise constitutive model. A hot processing map was constructed using the Dislocation Migration Model theory. Through comparative analysis with microstructures, it identified the optimal hot processing parameters for Incoloy825 superalloy within the range of 1110–1150 °C, 0.01–0.3 s−1, and 3.3–10 s−1. Microstructural analysis revealed a positive correlation between temperature and the extent of DRX in the alloy, with an acceleration in the transformation from Low-Angle Grain Boundaries (LAGB) to High-Angle Grain Boundaries (HAGB). The temperature of 1100 °C served as a critical point for the influence of strain rate on the microstructure. Below this temperature, DRX and HAGB proportions initially decreased and then increased with higher strain rates, while at higher temperatures, they directly correlated with strain rates. The study also investigated DRX mechanisms, determining Dynamic Discontinuous Recrystallization (DDRX) as the primary mechanism, more active at higher temperatures and strain rates. Continuous Dynamic Recrystallization (CDRX) served as a supplementary mechanism, especially in high-temperature and low-strain-rate deformation. Twins acted as favorable nucleation sites for DRX, facilitating both DDRX and Twin-DRX (TDRX) processes in Incoloy825 superalloy.
The Gleeble-3800 thermal simulator was used to perform hot compression experiments on Q345 steel at a temperature of 1123~1373 K, a strain rate of 0.01~10 s−1, and 60% deformation. Analysis of the ...flow curves of Q345 steel revealed that flow stress decreases with the increase of deformation temperature and decrease of strain rate. According to the stress–strain curve of Q345 steel, three constitutive models of Johnson–Cook, Modified Johnson–Cook and strain-compensated Arrhenius were established. By comparison, it was found that the strain-compensated Arrhenius model has higher accuracy, and its correlation coefficient and average relative error are 0.995 and 4.93%, respectively. In addition, the thermal processing map of Q345 steel was established, and the optimal processing range was temperature 1253–1373 K, strain rate 0.5–10 s−1.
Rare earth elements have been widely utilized in material manufacturing to enhance properties in various ways. In order to obtain the WC-10Co4Cr coating with uniform distribution of rare earths, ...CeO2-modified powder was prepared by mixing 1 wt.% nano-sized CeO2 during the initial ball-milling of the powder fabrication process. Bare and CeO2-modified WC-10Co4Cr coatings were deposited via high velocity oxygen fuel spraying to investigate the impact of CeO2 modification on the coating’s microstructure, mechanical properties and abrasive wear performance. The results show that the addition of CeO2 increased the interface energy, inhibiting the formation of the Co3W3C phase during the powder sintering process, as well as the W2C phase and CoCr alloy during the high-velocity oxy-fuel (HVOF) process. This led to a significantly decreased porosity and higher concentration of undissolved Cr-rich areas. The microhardness and fracture toughness of the CeO2-modified coating were 1230 HV0.3 and 5.77 MPam1/2, respectively. The abrasive wear resistance of the CeO2-modified coating was only 70.9% of that of the unmodified coating. Due to the weak cohesive strength between WC and Cr, Cr-rich areas were preferentially removed, resulting in an increased wear rate in the CeO2-modified coating.
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•A novel IBBR system was developed to treat landfill leachate and operated 343 days.•PN/A process was quickly started through inoculated activated sludge within 86 days.•The thicker ...biofilm enables the enrichment of denitrifying bacteria in BAF.•High TNRE of 93.3 % and NRR of 1.13 kg N/(m3·d) was achieved.•A high abundance of AnAOB (Ca. Kuenenia) was enriched, accounting for 1.7%.
Considering the challenges associated with nitrogen removal from mature landfill leachate, a novel combined continuous-flow process integrating denitrification and partial nitrification-Anammox (PN/A) was developed using an internal circulation (IC) system and a biological aerated filter (BAF) biofilm reactor (IBBR). In this study, IBBR successfully operated for 343 days, and when influent NH4+-N concentration of mature landfill leachate reached 1258.1 mg/L, an impressive total nitrogen removal efficiency (TNRE) of 93.3 % was achieved, along with a nitrogen removal rate (NRR) of 1.13 kg N/(m3·d). The analysis of the microbial community revealed that Candidatus Kuenenia, the dominant genus responsible for anammox, accounted for 1.7 % (day 265). Additionally, Nitrosomonas, Thauera and Truepera were identified as key contributors to the efficient removal of nitrogen from mature landfill. As a novel nitrogen removal strategy, the practical application of the IBBR system offers novel perspectives on addressing mature landfill leachate.
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•Quick start-up of Anammox process was achieved within 21 days.•The SNAD operates consistently and efficiently with an average DO of 0.051 mg/L.•The accumulation and dominance of ...AnAOB occur in the inner layers of biofilms.•The inhibition of NOB was effectively achieved in a continuous hypoxic environment.•The intermittent aeration operation mode was investigated.
In this study, a SNAD-SBBR process was implemented to achieve ammonia removal and carbon reduction of mature landfill leachate under extremely low dissolved oxygen conditions (0.051 mg/L) for a continuous operation of 266 days. The process demonstrated excellent removal performance, with ammonia nitrogen removal efficiency reaching 100 %, total nitrogen removal efficiency reaching 87.56 %, and an average removal rate of 0.180 kg/(m3·d). The recalcitrant organic compound removal efficiency reached 34.96 %. Nitrogen mass balance analysis revealed that the Anammox process contributed to approximately 98.1 % of the nitrogen removal. Candidatus Kuenenia achieved a relative abundance of 1.49 % in the inner layer of the carrier. In the SNAD-SBBR system, the extremely low DO environment created by the highly efficient partial nitrification stage enabled the coexistence of AnAOB, denitrifying bacteria, and Nitrosomonas, synergistically achieving ammonia removal and carbon reduction. Overall, the SNAD-SBBR process exhibits low-cost and high-efficiency characteristics, holding tremendous potential for landfill leachate treatment.
Arbuscular mycorrhizal fungi (AMF) play an important role in crop productivity, but their response to different fertilization regimes is variable. Understanding the mechanisms governing mycorrhizal ...responses under various fertilization regimes is key to maximizing the mycorrhizal contribution to ecosystem functioning. Indigenous AMF communities and soil were collected from long-term field experiments with various fertilization regimes. A greenhouse bioassay was carried out to identify the key regulators of the mycorrhizal response to inorganic and organic fertilization. Different fertilization regimes generated continuous gradients for most soil properties and a full spectrum of mycorrhizal phenotypes. Mycorrhizal growth response (MGR) in particular showed complex shifts from positive to neutral to negative, while mycorrhizal phosphorus (P) response was consistently positive and mycorrhizal nitrogen (N) response was consistently negative in fertilized treatments. Soil available P and available N to P (N:P) ratio appeared to be key soil predictors of the mycorrhizal response. Also, the nutrient status of non-mycorrhizal (NM) plants, namely shoot N concentration, shoot P concentration and shoot N:P ratio, were plant predictors of mycorrhizal response. A positive MGR occurred when NM plants were P-limited, and neutral and negative MGR occurred when NM plants were N-limited or co-limited by N and P. Further, the thresholds of soil available P (c. 13 mg kg-1), NM shoot N concentration (c. 14 g kg-1), NM shoot P concentration (c. 0.7 g kg-1) and NM shoot N:P ratio (c. 18), respectively, were estimated to predict mycorrhizal response. We conclude that the relative availability of N and P in soil and NM plants are good predictors of mycorrhizal response in different fertilization regimes. The existing nutrient thresholds combining soil and plant allowed more accurate prediction of mycorrhizal response and this has important implications for optimizing the mycorrhizal association in some important crops by managing soil nutrients.
•A wide spectrum of mycorrhizal phenotypes was observed in multiple fertilization regimes.•Soil P availability and N:P ratio were key soil predictors of mycorrhizal response.•N and P status of non-mycorrhizal plants were key plant predictors of mycorrhizal response.•Nutrient thresholds in soil and plants in predicting mycorrhizal response were identified.
Rare earth elements have been widely utilized in material manufacturing to enhance properties in various ways. In order to obtain the WC-10Co4Cr coating with uniform distribution of rare earths, ...CeOsub.2-modified powder was prepared by mixing 1 wt.% nano-sized CeOsub.2 during the initial ball-milling of the powder fabrication process. Bare and CeOsub.2-modified WC-10Co4Cr coatings were deposited via high velocity oxygen fuel spraying to investigate the impact of CeOsub.2 modification on the coating's microstructure, mechanical properties and abrasive wear performance. The results show that the addition of CeOsub.2 increased the interface energy, inhibiting the formation of the Cosub.3Wsub.3C phase during the powder sintering process, as well as the Wsub.2C phase and CoCr alloy during the high-velocity oxy-fuel (HVOF) process. This led to a significantly decreased porosity and higher concentration of undissolved Cr-rich areas. The microhardness and fracture toughness of the CeOsub.2-modified coating were 1230 HVsub.0.3 and 5.77 MPamsup.1/2, respectively. The abrasive wear resistance of the CeOsub.2-modified coating was only 70.9% of that of the unmodified coating. Due to the weak cohesive strength between WC and Cr, Cr-rich areas were preferentially removed, resulting in an increased wear rate in the CeOsub.2-modified coating.
In the era of the Internet of everything, the rapid increase in data volume and computation demand has prompted the evolution of application deployment mode from cloud computing to edge computing in ...order to reduce bandwidth consumption and response delay. However, there is a two-way selection problem between the application service provider (ASP) and the edge computing provider (ECP) in the process of task offloading. To solve this pro-blem, this paper proposes a combinatorial auction-based mechanism for task offloading in edge computing. First, this paper establishes a system model, explains the key issues of model implementation, proposes a heuristic task sel-ection algorithm for ECPs based on the analysis of their bidding process where choosing tasks to maximize resource utilization is proven to be an NP-complete problem, and then designs two auction algorithms, single-winner auction and multi-winner auction to fit trust-first and efficiency-first scenarios respectively. The experimental results show that
Purpose We determined the characteristics of Chinese men undergoing initial prostate biopsy and evaluated the relationship between prostate specific antigen levels and prostate cancer/high grade ...prostate cancer detection in a large Chinese multicenter cohort. Materials and Methods This retrospective study included 13,904 urology outpatients who had undergone biopsy for the indications of prostate specific antigen greater than 4.0 ng/ml or prostate specific antigen less than 4.0 ng/ml but with abnormal digital rectal examination results. The prostate specific antigen measurements were performed in accordance with the standard procedures at the respective institutions. The type of assay used was documented and recalibrated to the WHO standard. Results The incidence of prostate cancer and high grade prostate cancer was lower in the Chinese cohort than the Western cohorts at any given prostate specific antigen level. Around 25% of patients with a prostate specific antigen of 4.0 to 10.0 ng/ml were found to have prostate cancer compared to approximately 40% in U.S. clinical practice. Moreover, the risk curves were generally flatter than those of the Western cohorts, that is risk did not increase as rapidly with higher prostate specific antigen. Conclusions The relationship between prostate specific antigen and prostate cancer risk differs importantly between Chinese and Western populations, with an overall lower risk in the Chinese cohort. Further research should explore whether environmental or genetic differences explain these findings or whether they result from unmeasured differences in screening or benign prostate disease. Caution is required for the implementation of prostate cancer clinical decision rules or prediction models for men in China or other Asian countries with similar genetic and environmental backgrounds.
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