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Reabsorbing nutrients from senescent tissues before leaf falling has been recognized as a strategy to adapt to nutrient deficiency. However, how nutrient resorption modulates the nitrogen (N)–phosphorus (P) balance inside plants remains unclear, especially under increased soil N availability. We examined the impacts of N addition at varying rates (0–32 g N m−2 yr−1) on nutrient resorption and the performance of nutrient resorption on controlling the internal N–P balance in the leaf and stem of a dominant grass species, Leymus secalinus , in a saline–alkaline grassland in northern China. After 6 years of N addition, N concentration and N:P ratio in green and senesced tissues (leaf and stem) rose with increasing N addition. The P concentration in green tissues decreased, but did not significantly change in senesced tissues with increasing N addition. The N resorption efficiency (NRE), P resorption efficiency (PRE), and NRE:PRE ratio significantly decreased along the N addition gradient. Moreover, we found more sensitive responses of N:P ratio in senesced tissues than in green tissues; such exacerbation of plant internal N–P imbalances mainly resulted from a disproportionate reduction in nutrient resorption, especially NRE. Overall, our study suggested that differences in NRE and PRE further exacerbated the internal N–P imbalances in plant litters. [ABSTRACT FROM AUTHOR]

Soil dissolved organic matter (DOM) plays a critical role in regulating the cycling of terrestrial biogeochemistry. However, the influence mechanisms of nitrogen (N) addition on soil DOM concentration are not well understood at the regional scale. We performed a meta‐analysis of 1004 paired observations from 115 literature to explore how N addition affected the soil DOM concentration, including dissolved organic carbon (DOC) and nitrogen (DON), in China. Overall, N addition markedly stimulated the soil DOC and DON concentrations by 5.2% and 33.1%, respectively. This implied that the stimulation by increased N availability than the suppression by decreased soil pH played a more important role in the soil DOM concentration under N addition. The N addition level showed a significantly positive correlation with the soil DOC and DON concentrations under N addition. The N addition influence on soil DOC concentration was decreased along with the increase in initial soil total nitrogen (TN). This demonstrated the microbial N mining theory in the low N soils and the stoichiometric decomposition theory in the high N soils at the regional scale. The mean annual precipitation (MAP) potentially facilitated the leaching out of soil DON and displayed a negative impact on the soil DON concentration under N addition. The increased soil depth and initial soil pH depressed the soil DOC concentration whereas stimulated the soil DON concentration under N addition. This indicated that DOC mostly accumulated in the top soil and DON largely leached to the deep soil. And the initial soil pH with high value perhaps promoted the uptake of DOC for microbes and the solubility of DON, and thus resulted in the opposite influences on the soil DOC and DON concentrations. Our study provided a mechanistic understanding on N addition influence on the C and N dynamics of terrestrial ecosystem at the regional scale. [ABSTRACT FROM AUTHOR]

Anthropogenic disturbance, such as nitrogen (N) fertilization and mowing, is constantly changing the function and structure of grassland ecosystems during past years and will continue to affect the sustainability of arid and semiarid grassland in the future. However, how and whether the different N addition levels and the frequency of N addition, as well as the occurrence of mowing, affect the key processes of N cycling is still unclear. We designed a field experiment with five levels of N addition (0, 2, 10, 20, and 50 g N m−2 yr−1), two types of N addition frequencies (twice a year added in June/November and monthly addition), and mowing treatment in a typical grassland of northern China. The results showed that higher N addition and mowing interactively improved net primary productivity (NPP), including aboveground and belowground biomass, while different N addition frequency had no significant effects on NPP. Different N addition levels significantly improved gross ammonification (GA) and nitrification (GN) rates, which positively correlated to aboveground net primary productivity (ANPP). However, the effect of N addition frequency was differentiated with N addition levels, the highest N addition level (50 g N m−2 yr−1) with lower frequency (twice a year) significantly increased GA and GN rates. Mowing significantly increased the GA rate but decreased the GN rate both under the highest N addition level (50 g N m−2 yr−1) and lower N addition frequency (twice a year), which could improve N turnover by stimulating plant and microbial activity. However, a long-term study of the effects of N enrichment and mowing on N turnover will be needed for understanding the mechanisms by which nutrient cycling occurs in typical grassland ecosystems under global change scenarios. [ABSTRACT FROM AUTHOR]

The increase in atmospheric nitrogen (N) deposition has profound effects on soil respiration (SR). However, the responses of SR to the addition of different N compounds, particularly in saline–alkaline grasslands remain unclear. A 3-year controlled field experiment was conducted to investigate the responses of SR to different N compounds (NH4NO3, (NH4)2SO4 and NH4HCO3) during the growing seasons in a saline–alkaline grassland located in the agro-pastoral ecotone of northern China. Our results demonstrated that SR showed a bimodal pattern and a significant interannual difference that was regulated by air or soil temperature and precipitation. Nitrogen addition had a significant effect on SR, and the effect of N addition on SR varied yearly, which was related to seasonal precipitation. The mean SR across 3 years (2017–2019) was increased by 19.9%, 13.0% and 16.6% with the addition of NH4NO3, (NH4)2SO4 and NH4HCO3, respectively. The highest effect of NH4NO3 addition on SR across 3 years was ascribed to the highest aboveground net primary production, belowground net primary production (BNPP) and soil NO3− concentrations. SR (C loss) was significantly increased while plant productivity (C input) did not significantly change under NH4HCO3 addition, indicating a decrease in C sequestration. In addition, BNPP was the main direct factor influencing SR in this saline–alkaline grassland, and soil salinization (e.g. soil base cations and pH) indirectly affected SR through soil microorganisms. Notably, NH4NO3 addition overestimated the response of SR to N addition, and different N compounds should be considered, especially in saline–alkaline grassland. [ABSTRACT FROM AUTHOR]

The pools of plant community carbon (C) and nitrogen (N) are important sources of soil organic matter in terrestrial ecosystems and directly affect soil C and N cycling. A large amount of studies were manipulated with multiple N levels on soil C and N pools. However, how and whether the frequency of N addition can affect the plant C and N pools is still unclear. In order to comprehensively understand the N addition effects (including frequencies and levels) on C and N pools of the plant community, we executed a randomized complete block experiment with the addition of five levels of N, including 0, 2, 10, 20 and 50 g N m−2 yr−1 (designated as N-0, N-2, N-10, N-20 and N-50) and two N addition frequencies (twice a year vs. monthly, F2, F12) in August of 2008. After 5 years of treatment, the physical-chemical properties of the plants and soil were measured in 2013. The results indicated that with increasing N addition levels, the C and N pools of the plant community significantly increased, while N addition frequency had no significant effects. Moreover, significant interactions between N addition levels and the frequencies on the C and N pools of the plant community were also found in this typical grassland. Under different frequencies of N addition treatment, the plant community C and N pools showed different response patterns along with N addition levels in plants aboveground and belowground, respectively. Under different frequencies of N addition, the changes in the C and N pools of the plant community caused by N addition were regulated by different environmental factors. We highlight that long-term N deposition could affect the plant community C and N pools and would influence C and N cycling of terrestrial ecosystems based on global climate change in the future. [ABSTRACT FROM AUTHOR]

With the gradual development and competition among enterprises, the products of motion control system are diversified and the performance difference is bigger. The technology of motion control system is monopolized by a few foreign professional manufacturers. The development of motion controller in China is relatively late, and the number with independent research and development ability is still in the minority. Compared with foreign countries, some developed countries still restrict the export of high-end products to China. This paper will use Loongson 3A3000 processor to realize open motion controller. Loongson series processor is a general domestic processor developed by Institute of computing technology, Chinese Academy of Sciences. It uses MIPS instruction system. At present, Loongson is gradually catching up with and surpassing the world advanced level. The communication module of motion controller uses EtherCAT real-time Ethernet, which has the characteristics of high efficiency, flexible topology and short refresh cycle. At present, there are few cases of open motion controller based on domestic CPU Loongson, which provides a typical case for independent innovation in China. [ABSTRACT FROM AUTHOR]

This study proposed a scheme for drinking water treatment residue (DWTR) pretreatment to eliminate concerns about potential unfavorable effects caused by excessive release of nutrients (typically N) during recycling in restoration of a water environment with relatively low pollution (e.g., eutrophic surface water). Inspired by soil washing, the pretreatment scheme was based on washing processes; correspondingly, the N desorption characteristics, possibility of recycling solutions for subsequent desorption, and variations in DWTR adsorption capabilities were investigated. The results showed that N, mainly as ammonia N (NH 4 +-N), was quickly desorbed from DWTR; the concentrations of desorbed NH 4 +-N were an order of magnitude higher than those of nitrate N (NO 3 −-N). After six rounds of desorption, most ion-exchangeable NH 4 +-N was desorbed, and NH 4 +-N released from the DWTR (after the desorption test) declined markedly from 11.1 to <0.70 mg L−1 in initial column tests for surface water treatment. The same desorption characteristics of NH 4 +-N were observed for six DWTR collected from Australia, Ireland, and China, respectively; after N desorption, the adsorption capability of the six DWTR changed negligibly. Furthermore, electrochemical treatment was found to be effective in removing desorbed NH 4 +-N in solutions from DWTR; the treated solutions can be recycled for subsequent desorption without weakening NH 4 +-N desorption efficiencies, although NH 4 +-N removal efficiencies by electrochemical treatment tended to decline as the recycling of solutions increased to five rounds. Overall, the pretreatment scheme is scientifically feasible and can be applied and optimized based on remediation requirements in practical scenarios. • The ion-exchangeable N, mainly as NH 4 +-N, was quickly desorbed from DWTR. • Similar N desorption were observed for DWTR collected from different countries. • After N desorption, the adsorption capability of DWTR changed little. • The washing pretreatment is feasible for DWTR reuse in surface water restoration. [ABSTRACT FROM AUTHOR]

Background: Chronic obstructive pulmonary disease (COPD) has become a leading cause of morbidity and mortality in China, with tobacco smoke, air pollution, and occupational biohazards being the major risk factors. Objectives: The REACH trial is a multicenter, prospective, randomized controlled trial undertaken in China to assess the safety and effectiveness of the Spiration® Valve System (SVS) compared to standard medical care in COPD patients with severe emphysema. Methods: Patients with severe airflow obstruction, hyperinflation, and severe dyspnea with interlobar fissure integrity were evaluated for enrollment. A total of 107 subjects were randomized in a 2: 1 allocation ratio to either the treatment group (SVS valves and medical management) or the control group (medical management alone). Results: The 3-month primary endpoint showed statistically significant improvement in forced expiratory volume in 1 s in the treatment group compared to the control group (0.104 ± 0.18 vs. 0.003 ± 0.15 L, p = 0.001), with the difference being durable through 6 months. Statistically significant target lobe volume reduction was achieved at 3 months (mean change 684.4 ± 686.7 mL) and through 6 months (757.0 ± 665.3 mL). Exercise function and quality of life measures improved in the treatment group, but showed a deterioration in the control group. The serious adverse event (SAE) rate was 33% in the treatment group and 24.2% in the control group. The predominance of SAEs were acute exacerbations of COPD in both groups. There was 1 death in the control group and no deaths in the treatment group. Conclusion: The SVS represents a novel approach for the treatment of severe emphysema with a clinically acceptable risk-benefit profile. [ABSTRACT FROM AUTHOR]

Malignant central airway stenosis refers to airway stenosis caused by primary or metastatic malignant tumors which may lead to different levels of dyspnea or asphyxia in patients. With the rapid development of interventional pulmonology, therapeutic bronchoscopy has become one of the main methods for the diagnosis and treatment of malignant central airway stenosis. However, the level of diagnosis and treatment of respiratory intervention techniques in China is uneven at present, the treatment methods are not uniform, the treatment effects vary greatly, and some treatments even lead to serious complications. The interventional treatment technology for malignant central airway stenosis in China needs to be standardized. Therefore, the relevant experts of the Beijing Health Promotion Association Respiratory and Oncology Intervention and Treatment Alliance have formulated this consensus after several rounds of full discussion. [ABSTRACT FROM AUTHOR]

The aim of the present study was to investigate the predictive value of vancomycin serum concentrations regarding its efficacy and nephrotoxicity in a Chinese population and to determine a relatively safe optimal target concentration during vancomycin therapy. A total of 65 patients that received vancomycin between March 2013 and March 2018 at Shanghai 10th People's Hospital (Shanghai, China) were enrolled and their vancomycin trough and peak concentrations were monitored. Factor analysis was performed in order to exclude interaction between variables. Univariate and multivariate analyses were used to identify predictors of drug efficacy and nephrotoxicity. Receiver operating characteristic curve analysis was performed to determine the thresholds of the vancomycin trough and peak concentrations for optimal efficacy and acceptable nephrotoxicity, respectively. Among the 65 cases, treatment was deemed to be effective for 43 patients and ineffective for 22 patients. Furthermore, 20 patients fulfilled the criteria for nephrotoxicity. A total of 15 continuous variables loaded the first five factors by factor analysis (which converts large numbers of highly inter-correlated variables into a small number of comprehensive indicators that reflect a dimensionality reduction) and the factors were as follows: Inflammation, renal function, liver function, vancomycin trough and peak concentrations, and nutritional status. Univariate and multivariate analyses identified the trough concentration and peak concentration as independent variables associated with efficacy and nephrotoxicity of vancomycin, and the nutritional status was a risk factor associated with efficacy. Regarding efficacy, the critical values for the trough concentration and peak concentration were determined to be 9.02 mg/l (95.3% sensitivity and 68.2% specificity) and 23.62 mg/l (83.7% sensitivity and 59.1% specificity), respectively. The thresholds of vancomycin trough and peak concentrations for the development of nephrotoxicity were 16.08 mg/l (80.0% sensitivity and 84.4% specificity) and 30.42 mg/l (75.0% sensitivity and 73.3% specificity), respectively. In conclusion, during vancomycin therapy, the trough and peak concentrations are associated with efficacy and nephrotoxicity. Furthermore, a trough concentration between 9.02 and 16.08 mg/l and a peak concentration of 23.62–30.42 mg/l were determined to be relatively safe (the clinical trial registry no. ChiCTR-OPC-16007920). [ABSTRACT FROM AUTHOR]

Abstract: Nitrogen (N) ammonification and nitrification are two primary microbial processes controlling the availability of soil ammonium (NH4+), a key nutrient for vegetative growth. The large‐scale patterns of gross ammonification (GA) and gross nitrification (GN) rates represent soil microbial adaptations to different vegetative and environmental conditions. In this study, we investigated GA and GN rates in nine forest soils along a 3,700‐km north–south transect in eastern China. We used 15N‐labelling techniques, along with field experiments and laboratory incubations, to assess in situ and potential rates of the GA and GN. The mean in situ GA rate was 4.9 ± 0.5 mg N kg−1 day−1, whereas the mean potential rate of GA was 32.0 ± 8.6 mg N kg−1 day−1. The mean in situ GN rate was 1.7 ± 0.3 mg N kg−1 day−1 (potential GN rate: 3.2 ± 0.6 mg N kg−1 day−1). GA was significantly higher than GN along the transect, and there were high variations in GA and GN among different forests. Significant relationships were identified between meteorological factors (temperature and precipitation) and the GA and GN rates during the sampling month (August 2013). However, the mean GA rate in primary forest was significantly lower in the Huzhong (HZ), Dongling (DL), Taiyue (TY) and Dinghu (DH) sites compared with other sites, whereas with the exception of the Liangshui (LS) sampling site, the mean GN rate in primary and secondary forests showed the same trends. Significant differences in GA rates were found between primary and secondary forests at the LS and Changbai (CB) sites, and differences were detected in GN rate at the HZ, LS and Jiulian (JL) sites. Structural equation modelling analysis suggested that soil N contents, microbial biomass N pool sizes and bacterial abundance are the primary determinants of the in situ rates of GA and GN. The strong control of edaphic factors on GA and GN indicates a need to improve soil N models with more explicit representation of edaphic factors and their control on soil N transformations. A plain language summary is available for this article. [ABSTRACT FROM AUTHOR]

Wind-driven sediment resuspension exerts significant effects on the P behavior in shallow lake ecosystems. In this study, a comprehensive dynamic phosphorus (P) model that integrates hydrodynamic, wind wave and sediment transport is proposed to assess the importance of internal P cycling due to sediment resuspension on water column P levels. The primary contribution of the model is detailed modeling and rigorous coupling of sediment and P dynamics. The proposed model is applied to predict the P behavior in the shallow Taihu Lake, which is the third largest lake in China, and quantitatively estimate the effects of wind waves and lake currents on P release and distribution. Both the prevailing southeast winds in summer and northwest winds in winter are applied for the simulation, and different wind speeds of 5 m/s and 10 m/s are also considered. Results show that sediment resuspension and the resulting P release have a dominant effect on P levels in Taihu Lake, and likely similar shallow lakes. Wind-driven waves at higher wind speeds significantly enhance sediment resuspension and suspended sediment concentration (SSC). Total P concentration in the water column is also increased but not in proportion to the SSC. The different lake circulations resulting from the different prevailing wind directions also affect the distribution of suspended sediment and P around the lake ultimately influencing where eutrophication is likely to occur. The proposed model demonstrates that internal cycling in the lake is a dominant factor in the lake P and must be considered when trying to manage water quality in this and similar lakes. The model is used to demonstrate the potential effectiveness of remediation of an area where historical releases have led to P accumulation on overall lake quality. [ABSTRACT FROM AUTHOR]

The decay of algal biomass and aquatic plants in freshwater lakes leads to the overproduction of autochthonous organic matter (OM) and the exhaustion of dissolved oxygen, impacting the microbial community and subsequent biodegradation of emerging contaminants in sediment. This study explored how the microbial processing of aquatic plant- and algal-derived OM (POM and AOM) mediates 17α-ethinylestradiol (EE2) biodegradation in the anoxic sediments of Lake Taihu in China. In four months of microcosm incubations, the increased concentrations of protein-like substances in AOM and POM exhibited temporary activation on microbial metabolic enzyme activity (fluorescein diacetate hydrolase and dehydrogenase) and significantly promoted the carbon mineralization with iron reduction (P < 0.001). These in turn increased the EE2 biodegradation efficiency to 77–90 ng g−1 in the anoxic sediment. However, a higher EE2 biodegradation of 109 ng g−1 was achieved with the humic acid augmentation containing more quinone-like compounds, showing a weaker substrate-priming effect but accelerated redox cycling of iron and organic substrates in the later period of incubation. The microbial analysis further revealed that the quinone-like compounds in OM were more closely associated with microbial electron transfer and strengthened their interspecies syntrophic cooperation favorable to contaminant biodegradation, even though the connective members exposed to protein-like components upregulated more functional genes related to organic carbon and xenobiotics metabolism and biodegradation. Our findings will help predict the fate of estrogens in various sedimentary environments under increasing eutrophication and further climate change scenarios. [Display omitted] • Autochthonous OM enhanced microbial activity and C mineralization in anoxic sediment. • Priming effect on C mineralization and Fe(III) reduction accelerated EE2 degradation. • Different evolution and assembly of microbes exposed to protein- and quinone-like OM. • Quinone-like OM facilitated interspecies cooperation of electron transfer of microbes. • Hypoxia-induced inhibition exceeded promotion of autochthonous OM on EE2 degradation. [ABSTRACT FROM AUTHOR]

Abstract: In this work, the remediation of soils contaminated with multiple metals using ferric and alum water treatment residuals (FARs) in Baiyin, China, was investigated. The results of metals fractionation indicated that after the soil was treated with FARs, arsenic (As), lead (Pb), nickel (Ni), zinc (Zn) and copper (Cu) could be transformed into more stable forms, i.e., As bound in crystalline Fe/Al oxides and other metals in the oxidable and residual forms. However, the forms of chromium (Cr) and cadmium (Cd) were unaffected. Interestingly, due to the effect of FARs, barium (Ba) was predominantly transformed into more mobile forms. The bioaccessibility extraction test demonstrated that the FARs reduced the bioaccessibility of As by 25%, followed by Cu, Cr, Zn, Ni and Pb. The bioaccessibility of Cd and Ba were increased; in particular, there was an increase of 41% for Ba at the end of the test. In conclusion, the FARs can be used to remedy soil contaminated with multiple metals, but comprehensive studies are needed before practical applications of this work. [Copyright &y& Elsevier]

Aims Vegetation type is important in determining variations in soil carbon (C) efflux under grassland managements. This study was conducted to examine the effects of mowing and nitrogen (N) addition on soil respiration and their dependences upon vegetation types in an oldfield grassland of northern China. Methods Soil respiration, temperature, moisture and aboveground net primary productivity (ANPP) and belowground net primary productivity (BNPP) were examined in response to mowing and N addition among the three patches dominated by different species (named as grass, forb and mixed patches, respectively) in the growing seasons (May–October) from 2006 to 2008. Important Findings Across the 3 years, soil respiration in the grass patch was greater than those in the forb and mixed patches, which could have been ascribed to the higher soil moisture (SM) in the grass patch. Mowing had no impact on soil respiration due to unaltered SM and plant growth. Soil respiration was stimulated by 6.53% under N addition, and the enhancement was statistically significant in 2006 but not in 2007 or 2008 because of the limited water availability in the later 2 years. There were no interactive effects between mowing and N addition on soil respiration. Soil respiration showed positive dependence upon SM, ANPP and BNPP across plots. The results suggest that soil water availability and plant growth could be the primary factors in controlling the temporal and spatial variations in soil respiration and its response to different treatments. Our observations indicate that grassland managements (i.e. mowing for hay once a year) may have little influence on soil respiration of the oldfield grassland in northern China. [ABSTRACT FROM PUBLISHER]

Abstract: This study was conducted to examine the potential effects of ecological restoration by grazing exclusion on soil net nitrogen (N) mineralization over the growing season in the temperate steppe in this area. Both laboratory and in situ incubations with intact soil cores were used. Strong temporal variability in in situ net nitrification, net mineralization and available soil N were observed. Long-term (25 years) grazing exclusion stimulated in situ net nitrification whereas short-term (5 years) grazing exclusion had no effect. Neither long- nor short-term grazing exclusion affected net mineralization. Available soil N increased with time since grazing exclusion. Laboratory incubation showed that soil temperature affected net mineralization significantly and soil moisture effect depended on soil moisture range. The relationships of net mineralization with soil temperature and soil moisture observed in the laboratory incubation could not explain the temporal dynamics of in situ net mineralization. This study suggests that the grazing exclusion plays a positive role in regulating soil N availability, and thus stimulates the plant growth in the temperate steppe ecosystem in northern China. [Copyright &y& Elsevier]

Objectives:: To evaluate the reliability and validity of the Chinese versions of Minnesota Nicotine Withdrawal Scale and Questionnaire on Smoking Urges-Brief (MNWS-C and QSU-Brief-C) in Chinese smokers. [ABSTRACT FROM PUBLISHER]

Eutrophication of natural water commonly involves the pollution of both P and N. Here, we developed a new application of drinking water treatment residuals (DWTRs) for suspensions that permits the simultaneous removal of excess P and N from natural water and demonstrates that DWTRs recycling can provide a means for eutrophication control. Based on 364-day continuous flow tests, the suspension application of DWTRs effectively adsorbed P from overlying water under various conditions, decreasing total P concentrations from 0.0739 ± 0.0462 to 0.0111 ± 0.0079–0.0149 ± 0.0106 mg L−1, which achieved a class Ⅱ level of the China surface water quality standards during the tests. The total N concentrations were also reduced from 1.46 ± 0.63–1.52 ± 0.63 to 0.435 ± 0.185–0.495 ± 0.198 mg L−1, which achieved a class Ⅲ level during the stable stage of the tests. N removal was closely related to doses of DWTRs and aeration intensities. Effective N removal was mediated by the enriched microbial communities in the suspended DWTRs with simple, stable, and resilient networks, including many taxa associated with the N cycle (e.g., Rhodoplanes , Brevibacillus , and Pseudomonas). Further analysis indicated that both effective P adsorption and functional microbial community construction were closely related to Fe and Al in DWTRs. Suspension application prevented the burial effect of solids sinking from overlying water, which aided the ability of DWTRs to control pollution, and is potentially applicable to other materials for natural water remediation. • A new DWTRs application for suspensions was developed to control eutrophication. • Substantial P and N reductions in natural water were achieved by suspended DWTRs. • The simple and stable microbial communities in suspended DWTRs promoted N removal. • The favorable properties for both P and N removal were due to Fe and Al in DWTRs. [ABSTRACT FROM AUTHOR]

As the largest portion of the terrestrial ecosystems, the arid and semi-arid grassland ecosystem is relatively sensitive and vulnerable to nitrogen (N) deposition. Mowing, the main management in Inner Mongolia grassland also has deep direct and indirect effect on N transformation by removing the nutrient from soils. However, the interaction effect of N addition and mowing on N transformation is still unclear, especially in semi-arid grassland. Here, we conducted a field-manipulated experiment to assess N addition (10 g N m−2 y−1) and mowing (in the middle of August) effects on soil net N mineralization rate across 4 growing seasons (2006–2009) in a semi-arid grassland in Inner Mongolia of northern China. We found that N addition with or without mowing led to significant effect on soil ammonification rate and net N mineralization rate, but had no significant effect on nitrification rates. Furthermore, mowing had no significant effect on soil net N mineralization, ammonification and nitrification rates. N addition and Mowing decreased microbial respiration and metabolic quotient, whereas the interaction of N addition and mowing had no significant effect on microbial respiration and metabolic quotient. Our results indicated that the effects of mowing and N addition did not interactively weaken soil net N mineralization rates in a semi-arid grassland of Northern China. Therefore, the anthropic management (i.e. mowing for hay once a year) with N addition may be a sustainable approach for restoration and reconstruction of vegetation in the abandoned grassland of Northern China. [ABSTRACT FROM AUTHOR]

Soil aggregates play pivotal roles in soil organic carbon (SOC) preservation and climate change. Biochar has been widely applied in agricultural ecosystems to improve soil physicochemical properties. However, the underlying mechanisms of SOC sequestration by soil aggregation with biochar addition are not well understood at a large scale. Here, we conducted a meta-analysis of 2335 pairwise data from 45 studies to explore how soil aggregation sequestrated SOC after biochar addition in agricultural ecosystems of China. Biochar addition markedly enhanced the proportions of macro-aggregates and aggregate stability, and the production of organic binding agents positively facilitated the formation of macro-aggregates and aggregate stability. Soil aggregate-associated organic carbon (OC) indicated a significantly increasement by biochar addition, which was attributed to direct and indirect inputs of OC from biochar and organic residues, respectively. Biochar stimulated SOC sequestration dominantly contributed by macro-aggregates, and it could be interpreted by a greater improvement in proportions and OC protection of macro-aggregates. Furthermore, the SOC sequestration of soil aggregation with biochar addition was regulated by climate conditions (mean annual temperature and precipitation), biochar attributes (biochar C/N ratio and pH), experimental practices (biochar addition level and duration), and agronomic managements (land type, cropping intensity, fertilization condition, and crop type). Collectively, our synthetic analysis emphasized that biochar promoted the SOC sequestration by improving soil aggregation in agricultural ecosystems of China. • Biochar overall stimulated macro-aggregate proportions (14.1%–21.9%). • Biochar generally increased OC content in aggregates by 5.2%–60.5%. • Biochar-induced influences were controlled by ten important factors. • Biochar sequestrated SOC dominantly contributed by macro-aggregates. [ABSTRACT FROM AUTHOR]

• We addressed soil carbon fluxes in saline-alkaline grasslands. • Light grazing showed a negative effect on SR h. • Seasonal fluctuation of grazing effects resulted in unaltered seasonal mean SR. • Annual precipitation regulated the interannual variation of soil C emissions. • Soil environment explained SR more than plants and soil microorganisms. Grazing is a prevalent management strategy in grassland ecosystems that has profound effects on plants and soil microorganisms, consequently altering soil carbon (C) fluxes. However, the difference responses and regulatory mechanisms of soil autotrophic respiration (SR a) and heterotrophic respiration (SR h) to different grazing intensities remain unclear, especially in saline-alkaline grasslands. A six–year (2017–2022) field experiment involving four grazing intensities (no grazing, light grazing, moderate grazing, and heavy grazing) was conducted in a saline-alkaline grassland located in the agro-pastoral ecotone of northern China. Soil total respiration (SR tot) and its components (SR a and SR h), and the related biotic and abiotic factors (plants, soil microorganisms, and soil environment) were measured. The results showed that light grazing significantly decreased the mean SR h by 17.7% across six measuring years. The effects size of grazing on soil respiration fluctuated consistently with soil water content during the growing seasons (May–September), resulting in a neutral effect of grazing on the seasonal mean SR a. The cumulative soil C emissions of the current year varied with the seasonal precipitation in the previous year, whereas the changes in cumulative soil C emissions induced by grazing showed the same trends as annual precipitation. In addition, the key control factors for SR h and SR a differed and varied with grazing intensity and the soil environment played a critical role in regulating soil C fluxes. In conclusion, light grazing reduces soil microbial-driven C emissions and the soil environment and precipitation co-regulate the response of soil C fluxes to different grazing intensities in saline-alkaline grasslands. [ABSTRACT FROM AUTHOR]

Biological lability of dissolved organic matter (DOM) is a crucial indicator of carbon cycle and contaminant attenuation in freshwater lakes. In this study, we employed a multi-stage plug-flow bioreactor and spectrofluorometric indices to characterize the seasonal variations in DOM composition and lability across Poyang Lake (PY) and Lake Taihu (TH), two large freshwater lakes in China with distinct hydrological seasonality. Our findings showed that the export of floodplain-derived organics and river-lake interaction led to a remarkable increase in terrestrial aromatic and humic-like DOM with high molecular weights and long turnover times in PY. Consequently, the labile fraction was extremely low (average LDOC% of 3%) during the rising-to-flood season (spring and summer). Conversely, autochthonous production in TH considerably enriched semi-labile (average SDOC% of 26%) and biodegradable DOM (average BDOC% of 34%) during the phytoplankton bloom to post-bloom season (summer and autumn). This was reflected by the accumulation of low-light-absorbing and protein-like components with high biological and fluorescence indices. In the dry and non-bloom season (winter), the better preservation of humic substances maintained the high molecular weight and humic degree of DOM in PY, while the decay of aquatic plants strengthened autochthonous production, resulting in a similar BDOC% of PY samples (23%–34%) to TH samples (18%–33%). We further applied partial least squares regression using DOM optical indices as predictive proxies, which generated a greater prediction strength for BDOC% (R 2 = 0.80) compared to SDOC% (R 2 = 0.57) and LDOC% (R 2 = 0.28). The regression model identified aromaticity (SUVA 254) as the most effective and negative predictor and low molecular weight (A 250 / A 365) as the highly and positively influential factor. Our study provides new evidence that the seasonality of DOM lability profiles is regulated by the trade-off between flow-related variation and phytoplankton production, and presents an approach to describe and predict DOM lability across freshwater lakes. [Display omitted] • First study to directly compare DOM lability profiles in Poyang Lake and Lake Taihu. • Allochthonous aromatic organics input in flood season decreased BDOC% in Poyang Lake. • Autochthonous production increased BDOC% in bloom and post-bloom season of Lake Taihu. • Effective predictors of DOM lability included SUVA 254 , A 250 /A 365 , C/T, A/T, and HIX. • Higher predictive strength of DOM optical parameters for BDOC% than LDOC% and SDOC%. [ABSTRACT FROM AUTHOR]

• The N threshold of the unimodal response of CH 4 uptake was ∼10 g N m−2 yr−1. • The critical N addition rate to +/- abundance of pmoA gene was ∼7.0 g N m−2 yr−1. • N -induced changes in the plant community affect pmoA gene abundance through rhizospheric effects. Methane (CH 4) uptake in dryland ecosystems is a pathway in mitigating atmospheric CH 4 concentrations. A number of studies have demonstrated that nitrogen availability is a key regulator of the CH 4 oxidation process. However, how plants mediate soil CH 4 oxidation in response to N addition, particularly in saline-alkaline grasslands in the vast regions of the northern China, has received little attention. We conducted a 3-yr (2017–2019) in-situ experiment with eight N addition levels to examine the effect of N on soil CH 4 oxidation, and to explore the linkages between the N -induced changes of plant community and the seasonal dynamics of CH 4 in a saline-alkaline grassland. We found that the saline-alkaline grassland was a weak CH 4 sink displaying nonlinear CH 4 uptake levels in response to N additions, possibly due to the nonlinear changes in the abundance of key functional genes (pmoA) that were responsible for CH 4 oxidation. The changes in plant productivity and diversity that were induced by N additions explained 21 % of the variations in CH 4 uptake. The N -induced increase in productivity indirectly enhanced CH 4 uptake at N addition rates of <10 g m−2 yr−1, while the decrease in biodiversity indirectly inhibited CH 4 uptake when N addition exceeded 10 g m−2 yr−1. The N -induced changes in the plant community can affect CH 4 uptake, mainly through the rhizospheric effects of plants. In conclusion, our findings underscore the importance of rhizosphere when assessing the CH 4 uptake in saline-alkaline grassland ecosystems. [ABSTRACT FROM AUTHOR]

• There was an interaction between N addition and precipitation change on R s and R a. • R h was insensitive to N addition and precipitation change in saline-alkaline grassland. • R a was controlled by plants biomass, while R h was controlled by ST and soil pH. • Soil salinization regulated the effects of N addition and precipitation change on R s. The responses of soil total respiration (R s) and its components (soil autotrophic respiration (R a) and heterotrophic respiration (R h)) to nitrogen (N) deposition have been widely evaluated in non-saline-alkaline grasslands. However, their responses to N addition under drought and wet conditions, especially in saline-alkaline grasslands, remain unclear. A two-factorial experiment involving N addition and precipitation changes (decreased or increased 50% precipitation relative to ambient) was conducted in a saline-alkaline grassland of Northern China, while soil respiration was measured in different treatment plots during two growing seasons (2018, 2019). Results showed that the addition of N or changes in precipitation alone had no significant effect on R s , R a or R h in both years because root productivity and soil microbial biomass were not affected. However, N addition with increased precipitation synergistically augmented seasonal mean R s and R a by 25.7% and 46.8% in 2018, and by 42.4% and 89.3% in 2019, respectively, owing to the increase in plant productivity. The variation in R a primarily contributed to variation in R s , and the effect size of N addition on R s and R a were increased with precipitation. In addition, a structural equation model showed that the response of soil respiration to N addition and precipitation changes was regulated by soil salinization, in which the R a was regulated by soil based cations while R h was controlled by soil pH values. Our study highlights that N addition with increased precipitation preferentially affects plants rather than microorganisms, and that R h was not sensitive to N addition and precipitation changes in saline-alkaline grassland. [ABSTRACT FROM AUTHOR]

Gross ammonification (GA) and gross nitrification (GN) are key regulators of the bioavailability of nitrogen (N) in terrestrial ecosystems. In arid and semi-arid grassland ecosystems, the impacts of precipitation change on in situ GA and GN and their seasonal variations are understudied. A manipulative experiment with five precipitation levels (−60%, −30%, unchanged ambient precipitation as control, +30%, +60% of ambient precipitation) was set up in May 2012. After a 2-year equilibration period, the 15N pool dilution technique was applied to determine GA and GN rates in surface soil (0–5 cm) within 8 sampling dates ranging from the onset to the end of the growing season. Pronounced temporal variability of GA and GN rates were observed with the highest GA and GN rates in the mid-growing season (August) and the lowest in the post-growing season (October). GA rates during the growing season were primarily controlled by precipitation and soil water availability, while this effect diminished at the onset and end of the growing season when the temperature dropped. In contrast, GN was predominately controlled by ammonium (NH 4 +) production through GA. In the peak-growing season, the +60% precipitation treatment enhanced GA and GN rates by up to 4-fold, while the −30% precipitation treatment marginally suppressed GA and GN rates. The −60% precipitation treatment suppressed GA and GN rates to below detection limits across the entire study period, suggesting that extreme and persistent droughts greatly inhibited N turnover in the surface soil, thereby forcing plants to mobilize and access nutrients from deeper soil layers. Our findings provide a season-specific mechanistic insight into precipitation impacts on topsoil gross N turnover and suggest that the N cycling represented in ecosystem models needs to consider a mechanism that allows a strong suppression of microbial functions under extreme droughts. • Gross ammonification/nitrification (GA/GN) was strengthened by precipitation. • Temperature is limiting GA before and after the growing season. • GN is tightly coupled to substrate supply by GA. • Extreme drought with 60% precipitation reduction might terminate GA and GN. [ABSTRACT FROM AUTHOR]

Climate change and increasing eutrophication are expected to increase the release of autochthonous organic matter (OM) to sediments, where most contaminants are transformed or mineralized in freshwater lakes. This study sought to evaluate how cyanobacteria- and macrophyte-derived OM (COM and MOM) affected the microbial attenuation of 17α-ethinylestradiol (EE2) in the sediment from eutrophic Lake Taihu in China. In two months of water-sediment microcosm experiments, the input of COM and MOM both promoted EE2 degradation more strongly than humic acids, and the degradation efficiency was significantly and positively correlated with the cometabolism of increasing organic carbon in sediments (P < 0.001). The enhanced degradation was explained by responses of indigenous bacterial community to OM amendment as a priming effect. The immediate breakdown of biodegradable components such as proteinaceous substances in COM and MOM remarkably augmented the metabolic activity of bacteria in terms of the stimulated activity of extracellular enzymes including fluorescein diacetate and dehydrogenase, as well as the elevated production of proteins and polysaccharides in extracellular polymeric substances. In the meantime, the bacterial community composition was reshaped toward a more eutrophic state, leading to the clear upregulation of metabolic function genes of organic carbon and xenobiotics. Correlation-based network analysis further determined the strong facilitative coordination between the community members and the compositional variability of OM in the cometabolism. These results suggest that cyanobacterial blooms-dominated zones are potential hotspot areas for steroid estrogen attenuation, a finding of significance for the control and management of complex pollution in freshwater lakes. Image 1 • Input of autochthonous OM enhanced microbial degradation of EE2 in lake sediments. • EE2 degradation was positively related to cometabolism of degradable OM components. • Autochthonous OM increased bacterial metabolic enzyme activity and EPS secretion. • Facilitative interactions among microbes were promoted by proteinaceous substances. • Autochthonous OM upregulated xenobiotic metabolic function genes of bacterial group. [ABSTRACT FROM AUTHOR]

The fraction of net primary productivity (NPP) allocated to belowground organs (f BNPP ) in grasslands is a critical parameter in global carbon cycle models; moreover, understanding the effect of precipitation changes on this parameter is vital to accurately estimating carbon sequestration in grassland ecosystems. However, how f BNPP responds to temporal precipitation changes along a gradient from extreme drought to extreme wetness, remains unclear, mainly due to the lack of long-term data of belowground net primary productivity (BNPP) and the fact that most precipitation experiments did not have a gradient from extreme drought to extreme wetness. Here, by conducting both a precipitation gradient experiment (100-500 mm) and a long-term observational study (34 years) in the Inner Mongolia grassland, we showed that f BNPP decreased linearly along the precipitation gradient from extreme drought to extreme wetness due to stronger responses in aboveground NPP to drought and wet conditions than those of BNPP. Our further meta-analysis in grasslands worldwide also indicated that f BNPP increased when precipitation decreased, and the vice versa. Such a consistent pattern of f BNPP response suggests that plants increase the belowground allocation with decreasing precipitation, while increase the aboveground allocation with increasing precipitation. Thus, the linearly decreasing response pattern in f BNPP should be incorporated into models that forecast carbon sequestration in grassland ecosystems; failure to do so will lead to underestimation of the carbon stock in drought years and overestimation of the carbon stock in wet years in grasslands., (© 2024 John Wiley & Sons Ltd.)

Water-soluble inorganic ions (WSIIs, primarily NH 4 + , SO 4 2- , and NO 3 - ) are major components in ambient PM 2.5 , but their reproductive toxicity remains largely unknown. An animal study was conducted where parental mice were exposed to PM 2.5 WSIIs or clean air during preconception and the gestational period. After delivery, all maternal and offspring mice lived in a clean air environment. We assessed reproductive organs, gestation outcome, birth weight, and growth trajectory of the offspring mice. In parallel, we collected birth weight and placenta transcriptome data from 150 mother-infant pairs from the Rhode Island Child Health Study. We found that PM 2.5 WSIIs induced a broad range of adverse reproductive outcomes in mice. PM 2.5 NH 4 + , SO 4 2- , and NO 3 - exposure reduced ovary weight by 24.22% (p = 0.005), 14.45% (p = 0.048), and 16.64% (p = 0.022) relative to the clean air controls. PM 2.5 SO 4 2- exposure reduced the weight of testicle by 5.24% (p = 0.025); further, mice in the PM 2.5 SO 4 2- exposure group had 1.81 (p = 0.027) fewer offspring than the control group. PM 2.5 NH 4 + , SO 4 2- , and NO 3 - exposure all led to lower birth than controls. In mice, 557 placenta genes were perturbed by exposure. Integrative analysis of mouse and human data suggested hypoxia response in placenta as an etiological mechanism underlying PM 2.5 WSII exposure's reproductive toxicity.

The necessity on controlling internal P pollution has been widely reported for lake restoration; thus far, cutting the migrations of soluble P from sediment to overlying water, especially under anoxic condition, is the main target of the internal P pollution control to achieve favorable ecological responses in lake. Here, according to the types of P directly available by phytoplankton, phytoplankton-available suspended particulate P (SPP) pollution, which mainly occurs under aerobic condition and due to sediment resuspension and soluble P adsorption by suspended particle, is found to be the other kind of internal P pollution. The SPP has long been a key index for environmental quality assessment, which could be indirectly reflected by the developed various methods for phytoplankton-available P pool analysis; also, the P has been demonstrated to be a major cause of phytoplankton breeding, typically in shallow lakes. Importantly, compared to the soluble P, SPP pollution clearly has more complicated loading pathways and P activation mechanisms and involves in different fractions of P, even part of which are with relatively high stability in sediment and suspended particle, leading to the potential control measures for the pollution being more complex. Considering the potential differences of internal P pollution among various lakes, this study is therefore calling for more research to focus on regulating phytoplankton-available SPP pollution. Recommendations are also offered to bridge knowledge gap of the regulation to design proper measures for lake restoration., 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 © 2023 Elsevier Ltd. All rights reserved.)

Context: In the process of combating the coronavirus disease 2019 (COVID-19) epidemic, medical personnel were at the forefront of the fight. As the future medical workforce, medical students often experienced firsthand how their seniors and teachers had to commit to working hard in combating the epidemic. Many were directly involved in the front line of the fight and that experience could easily have affected their intention to seek employment in a medically related career., Objective: The study intended to evaluate the impact of the COVID-19 pandemic on Chinese medical students' employment intentions and the factors associated with them to put forward relevant suggestions to provide a basis for medical education in the future., Design: The research team conducted a cross-sectional study, using an anonymous online questionnaire., Setting: The study took place in many provinces and cities in China and was conducted in an online questionnaire., Participants: Participants were 1114 college students studying clinical medicine, college students studying nursing, and students interning during standardized resident training, medical interns., Outcome Measures: The participants completed a self-administered questionnaire, which investigated their psychological statuses related to anxiety and depression as well as COVID-19's impact on their intentions related to job searches, regarding their willingness to engage in clinical or basic research in epidemic-related specialties and epidemic-related work., Results: Compared to college students studying clinical medicine, the employment intentions of nursing students and medical interns were more vulnerable to the epidemic. Females and nursing students were more reluctant to choose clinical work, and the choice was associated with depression. Nursing college students and medical interns were significantly less willing to engage in infection medicine, respiratory medicine, and intensive care medicine (all P < .001). Medical students with a bachelor's degree and postgraduate degrees were significantly less willing to engage in infection medicine and respiratory medicine (all P < .001), but medical students from regions with stable epidemics were more willing to engage in intensive care medicine. Medical students with a bachelor's degree were significantly less likely to be involved in epidemiology-related work than undergraduate students, and students from severe epidemic regions were significantly less willing to work in isolation wards or to go to Wuhan as volunteers., Conclusions: Participants' psychological statuses related to anxiety and depression, genders, degrees, current educational statuses, and regions affected employment intentions during the epidemic.

The typical harm effect of algal bloom sedimentation is to increase sulfides level in surroundings, threatening aquatic organisms and human health; whereas, P inactivating materials containing sulfate are commonly attempted to be used to immobilize reactive P or to flocculate excessive algae in water columns for eutrophication control. In this study, variations in sulfate reduction during algal bloom sedimentation with the addition of sulfate based inactivating materials was comprehensively assessed based on using Al 2 (SO 4 ) 3 with comparison to AlCl 3 . The results showed that addition of Al 2 (SO 4 ) 3 had more substantial effect on overlying water and sediment properties compared to those of ACl 3 . Al 2 (SO 4 ) 3 can enhance sulfate reduction, resulting in temporary increase of sulfides (p < 0.01) and quick decrease of various Fe (p < 0.01) in overlying water and then promoting the formation of FeS and FeS 2 (determined by EXAFS analysis) in sediments. Most importantly, the increased sulfides, as well as the physical barrier on sediment formed due to Al 2 (SO 4 ) 3 addition, enhanced the transformation of sulfides to odorous contaminants, increasing odorous contaminants (especially methyl thiols) production by approximately one order of magnitude in overlying water. Furthermore, the increased sulfides facilitated to the enrichment of microorganisms related to S cycles (Thiobacillu with relative abundance of 23.8%) and even promoted to enrich bacterial genus potentially with pathogenicity (Treponema) in sediments. The impacts of sulfate tended to be regulated by algae concentration; however, careful management was recommended for sulfate based inactivating materials application to control eutrophication with algal blooms., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Introduction: To investigate the effects and influencing factors of the COVID-19 epidemic on the employment intention of resident physicians in China., Methodology: 409 questionnaires were statistically analyzed after removing the missing values. We used the Chi-Square test for single-factor analysis and logistic regression analysis for multivariate analysis. The questions include the residents' employment intention and their willingness to engage in epidemic-related subspecialties and participate in epidemic-related work., Results: Residents of severe and high-risk epidemic regions had much lower employment intentions than those of stable epidemic regions (OR = 1.917, 95% CI: 1.024, 3.591, p = 0.042). The higher the Center for Epidemiologic Studies Depression Scale (CES-D) score, the more susceptible was the resident's employement intention (OR = 1.085, 95% CI: 1.044, 1.128, p < 0.001). Residents from severe and high-risk epidemic regions were more willing to participate in clinical work (OR = 4.263, 95% CI: 1.892, 9.604, p < 0.001), and the higher the CES-D score, the lower was the proportion of residents willing to choose clinical work (OR = 0.941, 95% CI: 0.893, 0.992, p = 0.023). Residents from severe epidemics and high-risk provinces were less willing to participate in respiratory medicine (χ2 = 5.070, p = 0.027) and critical care medicine (χ2 = 7.046, p = 0.011). Compared to residents with bachelor's degrees, residents with master's and doctoral degrees were less willing to participate in isolation wards (OR = 1.831, 95% CI: 1.122, 2.990, p = 0.016). Residents in epidemic-related current rotation departments were less willing to go to Wuhan as volunteers (OR = 2.197, 95% CI: 1.110, 4.347, p = 0.024)., Conclusions: The COVID-19 outbreak had a negative impact on the job intentions of Chinese residents in general., Competing Interests: No Conflict of Interest is declared, (Copyright (c) 2022 Xuan Long, Jie Zhang, Jia Chen, Lishuai Shi, Xuan Li, Wanwan Yi, Zichen Chen, Sinthu Kosasih, Zhen Yu, Aihong Mei, Changhui Wang.)

While fluid sediments normally formed through hydrodynamic erosion and transport was well known, the fluid sediments caused by organic matter accumulation and degradation in eutrophic lakes was rarely investigated. Here, the effects of cyanobacterial bloom biomass (CBB) accumulation and water depth on the occurrence of fluid sediments were studied. Within 30 days of experiments, the variation of sediment height firstly increased to the maximum with rising in water depth, then decreased due to the high hydraulic pressure. While the surface sediments density decreased slightly from 1.35 g cm -3 to around 1.32 g cm -3 without CBB accumulation, and CBB accumulation led to lower density (around 1.02 g cm -3 ) but higher shear stress of sediments. Through analyzing the extracellular polymeric substances (EPS), it was found that CBB accumulation improved the polysaccharide/protein ratios of sediment. The infrared analysis further indicated that the bound-EPS could protect fluid sediments bio-stabilization. Meanwhile, the enriched Acinetobacter, Pseudomonas in sediments with CBB accumulation might play roles in EPS production, which benefited the bio-stabilization of fluid sediments. Furthermore, the stability of fluid sediments increased with increase in water depth, and the resuspension of biological fluid sediments would occur more likely in the low water depth area. Altogether, this study reported the formation and stability of the biological fluid sediments in eutrophic shallow lakes, and could help provide clues against sediment resuspension in lake ecosystems., 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.)

Biological nitrogen fixation (BNF) in sediments is an important source of bioavailable nitrogen in aquatic systems. However, the effect of habitat change caused by eutrophication on nitrogen fixation within sediments is still unclear. In this study, nitrogen fixation rates and diazotroph diversities in sediments with heterogeneous ecological status in one eutrophic lake were investigated by using an isotope tracer method and sequencing of nitrogen-fixing (nif) genes. The results showed that both nitrogenase activity (NA) and nifH abundance in sediments of blooms area were higher than those in vegetation-dominated habitats. Correlation analysis showed that NA was correlated closely to nifH abundance, dissolved sulfide, and iron. The diazotrophic assemblage contained mainly Proteobacterial sequences belonging to Cluster I and III, and the variations of diazotrophic community could be explained by total nitrogen content, total phosphorus content, organic matters, sulfides, ammonium and iron content. Moreover, the co-occurrence network analysis showed the Alphaproteobacteria shaped the major interactions in diazotrophic community, and sediment properties had stronger effect on diazotrophic community in cyanobacteria-dominated habitat. This study revealed that habitat heterogeneity in eutrophic lakes shaped different succession of BNF in sediments and cyanobacterial blooms significantly improved the nitrogen-fixing activity in sediments, which broadened our understanding of nitrogen cycle and nutrient management in eutrophic freshwater lakes., 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: Although traditional diagnostic techniques of infection are mature and price favorable at present, most of them are time-consuming and with a low positivity. Metagenomic next⁃generation sequencing (mNGS) was studied widely because of identification and typing of all pathogens not rely on culture and retrieving all DNA without bias. Based on this background, we aim to detect the difference between mNGS and traditional culture method, and to explore the relationship between mNGS results and the severity, prognosis of infectious patients., Methods: 109 adult patients were enrolled in our study in Shanghai Tenth People's Hospital from October 2018 to December 2019. The diagnostic results, negative predictive values, positive predictive values, false positive rate, false negative rate, pathogen and sample types were analyzed by using both traditional culture and mNGS methods. Then, the samples and clinical information of 93 patients in the infected group (ID) were collected. According to whether mNGS detected pathogens, the patients in ID group were divided into the positive group of 67 cases and the negative group of 26 cases. Peripheral blood leukocytes, C-reactive protein (CRP), procalcitonin (PCT) and neutrophil counts were measured, and the concentrations of IL-2, IL-4, IL-6, TNF-α, IL-17A, IL-10 and INF-γ in the serum were determined by ELISA. The correlation between the positive detection of pathogens by mNGS and the severity of illness, hospitalization days, and mortality were analyzed., Results: 109 samples were assigned into infected group (ID, 92/109, 84.4%), non-infected group (NID, 16/109, 14.7%), and unknown group (1/109, 0.9%). Blood was the most abundant type of samples with 37 cases, followed by bronchoalveolar lavage fluid in 36 cases, tissue, sputum, pleural effusion, cerebrospinal fluid (CSF), pus, bone marrow and nasal swab. In the ID group, the majority of patients were diagnosed with lower respiratory system infections (73/109, 67%), followed by bloodstream infections, pleural effusion and central nervous system infections. The sensitivity of mNGS was significantly higher than that of culture method (67.4% vs 23.6%; P < 0.001), especially in sample types of bronchoalveolar lavage fluid (P = 0.002), blood (P < 0.001) and sputum (P = 0.037), while the specificity of mNGS was not significantly different from culture method (68.8% vs 81.3%; P = 0.41). The number of hospitals stays and 28-day-motality in the positive mNGS group were significantly higher than those in the negative group, and the difference was statistically significant (P < 0.05). Age was significant in multivariate logistic analyses of positive results of mNGS., Conclusions: The study found that mNGS had a higher sensitivity than the traditional method, especially in blood, bronchoalveolar lavage fluid and sputum samples. And positive mNGS group had a higher hospital stay, 28-day-mortality, which means the positive of pathogen nucleic acid sequences detection may be a potential high-risk factor for poor prognosis of adult patients and has significant clinical value. MNGS should be used more in early pathogen diagnosis in the future.

As a recently discovered process of nitrogen cycling, anaerobic ammonium oxidation coupled to ferric iron reduction (Feammox) has attracted more attentions. This study investigated the spatial variation of Feammox in the sediment of different zones of a shallow freshwater lake and the effect of organic matter derived from algae and macrophyte on Feammox process. The potential Feammox rates showed significant differences among sediments from algae-dominated area (ADA), transitional area in the center of the lake (TDA), and macrophyte-dominated area (MDA), and in a descending order, ADA, MDA, and TDA. The potential Feammox rate ranged from 0.14 to 0.34 mg N kg -1 day -1 in the freshwater lake sediment. The potential Feammox rates of the sediment with algae or macrophyte amendment were 12.29% and 15.31% higher than the control test without algae and macrophyte amendment. The addition of algae or macrophyte to the sediment from TDA could improve the amount of HCl-extractable total Fe, Fe(III) reduction rate, and the abundance of FeRB. These results demonstrated that organic matter is one of the key regulators of Feammox process.

Background: Air pollution is a leading cause of global disease burden. Lack of suitable methods for long term measuring exposure level at individual level is crippling environmental epidemiology research of air pollution., Methods: We report an integrative system, Bio 3 Air, for long term measurement of individual level air pollution exposure, currently focusing on ambient particulate matter (PM). The novel system in real-time quantifies individual's outdoor/indoor status, geological location, lung ventilation rate and PM concentration of individual's surrounding environment, and these metrics are subsequently incorporated in calculating PM exposure., Results: The system is fully developed and tested in China, USA and Canada, and has been successfully applied in epidemiology study. Bio 3 Air offers high reliability, sensitivity, reproducibility (>99%) and accuracy. It has high time- and spatial- resolution (≤ 2 min and ≤ 20 m, respectively). Bio 3 Air achieved 91.89% consistency with "gold-standard" method (membrane collection and off-line analysis)., Conclusions: Bio 3 Air represents a substantial methodological advance in environmental health research of air pollution. It captures information relevant in measuring individual's PM exposure (e.g. real-time outdoor/indoor status, location and lung ventilation rate). Such information is typically missed by conventional approaches. Additional features of Bio 3 Air include easy-to-use, cost-effectiveness and automated data collection, making it a powerful tool facilitating studies of air pollution exposure and health consequences., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Natural dissolved organic matter (DOM) produced in algal blooms and overgrowths of macrophyte changes the elimination and ecotoxicity of estrogens in freshwater lakes. The complexation of 17α-ethinylestradiol (EE2) and various DOMs, including the water- and sediment-derived DOMs from the algal-dominant zone in Lake Taihu (TW and TS, respectively) and the macrophyte-dominant zone in Poyang Lake (PW and PS, respectively), and the humic acid (HA), was investigated along with the subsequent effects on EE2 biodegradation. Dialysis equilibrium experiments showed that binding to DOM significantly decreased the freely soluble concentrations of EE2. The binding capacity of the five DOMs followed the order of PW < TW < PS ≈ TS < HA. A negative correlation was found between the organic-carbon-normalized sorption coefficient (logK DOC ) and the absorption ratio (E 2 /E 3 ) of DOM, indicating that the large sized, aromatic molecules were involved in the complexation. The reduced freely soluble concentrations of EE2 did not inhibit its biodegradation by an EE2-degrading strain, Rhodobacter blasticus. Conversely, the autochthonous-dominated water-derived DOMs stimulated a more extensive biodegradation of EE2 than the sediment-derived DOMs, and the existence of HA resulted in the smallest increase in EE2 biodegradation. The promoting effect was associated with the increased concentration, activity, and transforming rate of R. blasticus by the bioavailable components in DOM. The present study suggests that the significant impact of natural DOM should be fully considered when assessing the fate and ecological risks of estrogens in eutrophic waters., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: Ambient particulate matter (PM) exposure has been associated with respiratory function decline in epidemiological studies. We hypothesize that a possible underlying mechanism is the perturbation of airway microbiome by PM exposure., Methods: During October 2016-October 2017, on two human cohorts (n = 115 in total) in Shanghai China, we systematically collected three categories of data: (1) respiratory functions, (2) airway microbiome from sputum, and (3) PM 2.5 (PM of ≤ 2.5 µm in diameter) level in ambient air. We investigated the impact of PM 2.5 on airway microbiome as well as the link between airway microbiome and respiratory functions using linear mixed regression models., Results: The respiratory function of our primary interest includes forced vital capacity (FVC) and forced expiratory volume in 1st second (FEV 1 ). FEV 1 /FVC, an important respiratory function trait and key diagnosis criterion of COPD, was significantly associated with airway bacteria load (p = 0.0038); and FEV 1 was associated with airway microbiome profile (p = 0.013). Further, airway microbiome was significantly influenced by PM 2.5 exposure (p = 4.48E-11)., Conclusions: To our knowledge, for the first time, we demonstrated the impact of PM 2.5 on airway microbiome, and reported the link between airway microbiome and respiratory functions. The results expand our understanding on the scope of PM 2.5 exposure's influence on human respiratory system, and point to novel etiological mechanism of PM 2.5 exposure induced diseases., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Rewetting after precipitation events plays an important role in regulating soil carbon (C) and nitrogen (N) turnover processes in arid and semiarid ecosystems. Here, we conducted a 48-h rewetting simulation experiment with measurements of soil C and N mineralization rates (R C and R N , respectively) and microbial biomass N (MBN) at high temporal resolution to explore the pulse responses of R C and R N . R C and R N responded strongly and rapidly to rewetting over the short term. The maximum R C value (because of pulse effects) ranged from 16.53 to 19.33 µg C g soil -1 h -1 , observed 10 min after rewetting. The maximum R N varied from 22.86 to 40.87 µg N g soil -1 h -1 , appearing 5-6 h after rewetting. The responses of soil microbial growth to rewetting were rapid, and the maximum MBN was observed 2-3 h after rewetting. Unexpectedly, there was no correlation between R C , R N , and MBN during the process of rewetting, and R C and R N were uncoupled. In sum, the pulse responses of R C , R N , and microbial growth to simulated rewetting were rapid, strong, and asynchronous, which offers insights into the different responses of microbes to rewetting and mechanisms behind microbes.

The study was conducted to investigate the relationship between vitamin D receptor (VDR) gene rs2228570 and rs1544410 polymorphisms and pancreatic cancer (PC). Two hundred fifty-eight PC patients and 385 healthy controls were enrolled in this study. The genotypes of rs2228570 and rs1544410 were assayed using the polymerase chain reaction/restriction fragment length polymorphism (PCR-RFLP) method. Univariate and multivariate logistic regression analyses were applied to determine the association between PC-onset risk and VDR gene polymorphisms. Contingency table analysis was performed to evaluate the relationship between the gene polymorphisms and clinicopathological tumor features such as location, pathological differentiation, and the TNM classification of PC. In rs2228570, the T loci and genotypes with T allele could increase the risk of PC; in rs1544410, the G loci and genotypes AG + GG could decrease the onset risk of PC significantly. The contingency table analysis indicated that the rs2228570 polymorphisms were correlated with the pathological differentiation of PC significantly, and the rs1544410 polymorphisms were correlated with the TNM classification of PC significantly. In conclusion, the VDR gene polymorphisms were correlated with incidence, pathological differentiation, and the TNM classification of PC significantly in our study population. So, the VDR polymorphisms have important implications in the incident rate and survival rate of PC.