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Purpose: Vanadium (V) contamination in soil can cause diverse damage to soil ecosystem and has attracted research interests in exploring soil V stabilization methods, but only a few materials were proposed and studied. Here, a pot experiment was firstly conducted to estimate the efficiency of nano-hydroxyapatite (n-HAP) in stabilizing V in soil. To verify the impact of n-HAP on soil V bioavailability and phytotoxicity, cabbages (Brassica chinensis L.) were grown in V-spiked soils after n-HAP amendment. Materials and methods: Soils were sampled from a farmland in China, and the n-HAP was prepared in the laboratory. In each pot of soil spiked with 0, 75, 150, 300, and 600 mg/kg V, 2% n-HAP was amended for 30 days, while soils without n-HAP amendment were set as controls. The stabilization effect of n-HAP on V in soil was estimated by the water-extractable and bioavailable V concentrations in soils. Cabbages were grown in pots subsequently. The V(V/IV) concentrations in cabbage leaves and roots, the organic bound V concentrations in cabbage roots, and the chlorophyll concentrations in leaves were determined. Bioconcentration factor and translocation factor were calculated. The composition of organic bound V in leaf was characterized by fluorescence excitation–emission matrix. Results and discussion: In soils spiked with 150 mg/kg V, n-HAP amendment yielded the highest stabilization rates of 51.0% and 42.4% for water-extractable and bioavailable V, respectively. In 75, 150, and 300 mg/kg V-spiked soil, the plant weight, plant height, and root length of cabbage after 60-day growing decreased 54.6%/89.6%, 30.9%/45.5%, and 41.5%/51.4% in groups with/without n-HAP, respectively. Cabbage leaf chlorophyll concentrations descend firstly then ascend with rising soil V concentration. Leaf V speciation analysis revealed that less leaf V was reduced to V(IV) in groups amended with n-HAP than groups without n-HAP amendment. In 150 and 300 mg/kg V-spiked soil, n-HAP effectively reduced the V content and the V bioconcentration factor of cabbage root. Tyrosine-like and humic acid-like analogues composed the principal part of V complex. Conclusions: In general, n-HAP amendments are potential to decrease the mobility of V in soils, as well as inhibit the bioavailability and phytotoxicity of V to cabbage. In V-spiked soils, n-HAP amendment can alleviate the toxicity of V to the cabbage. Overall, 2% n-HAP is efficient for the amendment of slight V-polluted (150–300 mg/kg) soils to alleviate the soil V stress to cabbage. [ABSTRACT FROM AUTHOR]

There are many factors that affect how urban tree species absorb and use nutrients, but little is known about the impact of pavement in urban areas. In this study, we selected four common urban tree species— Platanus x acerifolia , Metasequoia glyptostroboides , Robinia pseudoacacia , and Pinus thunbergii —and three pavement coverage categories—unpaved, semi-paved, and fully paved—in Qingdao, a typical city in northern China, to investigate changes in the leaf nutrient utilization strategies of tree species in paved environments. The nitrogen (N) resorption efficiency (NRE) and phosphorus (P) resorption efficiency (PRE) of R. pseudoacacia and the NRE of M. glyptostroboides increased in semi- and fully paved environments. Additionally, the N resorption proficiency of M. glyptostroboides increased significantly with pavement coverage, indicating that the biochemical limitation on N resorption was weakened. Similarly, the contents of N, P, and potassium (K) in R. pseudoacacia and N and K in M. glyptostroboides significantly increased with pavement coverage. This indicates that R. pseudoacacia , a nitrogen-fixing Fabaceae tree species, and M. glyptostroboides , a deciduous Cupressaceae tree species, can better adapt to pavement in urban settings, and even high pavement coverage levels can induce higher nutrient contents and resorption capacities. In addition, M. glyptostroboides showed potentially poor adaptability for N, P, and K uptake in the more stressful pavement environments, and P. x acerifolia showed relatively poor adaptability in P-limited environments. Robinia pseudoacacia associates with nodule-forming nitrogen-fixing bacteria, thus retaining more N in its leaves and showing a low NRE. These findings not only provide additional insight into tree growth at varying pavement coverages but also preliminary guidance for tree species selection to promote resilience in urban areas. • Ground pavement over tree root systems affected nutrient resorption capacity of urban trees. • Urban tree species exhibited different adaptability strategies under different pavement environments. • Differences in ecological plant type may explain nutrition differences. [ABSTRACT FROM AUTHOR]

Phosphogypsum (PG) stored close to phosphorus chemical plants has caused worldwide environmental problems. Column leaching experiments were conducted to evaluate Ca and Sr leaching from PG under simulated acid rain at pH levels typical for rain in the study region (Shifang, China). High concentrations of Ca and Sr in leachates in the first five leaching events could pollute the soil and groundwater around the PG. Leachates pH was lower than and had no correlation with simulated rain pH. No correlations between simulated rain pH and cumulative Ca and Sr content in leachates were noted. Around 2.0%–2.2% of Ca and 0.5%–0.6% of Sr were leached out from PG by the simulated summer rainfall in Shifang. Electrical conductivity values, Ca and Sr concentrations at bottom sections of PG columns were higher than those of top sections, while pH values showed a reverse trend. More precautions should be taken to protect the environment around PG stacks. [ABSTRACT FROM AUTHOR]

Partitioning soil respiration ( RS) into heterotrophic ( RH) and rhizospheric ( RR) components is an important step for understanding and modeling carbon cycling in forest ecosystems, but few studies on RR and RH exist in Chinese temperate forests. In this study, we used a trenching plot approach to partition RS in six temperate forests in northeastern China. Our specific objectives were to (1) examine seasonal patterns of soil surface CO2 fluxes from trenched ( RT) and untrenched plots ( RUT) of these forests; (2) quantify annual fluxes of RS components and their relative contributions in the forest ecosystems; and (3) examine effects of plot trenching on measurements of RS and related environmental factors. The RT maximized in early growing season, but the difference between RUT and RT peaked in later summer. The annual fluxes of RH and RR varied with forest types. The estimated values of RH for the Korean pine ( Pinus koraiensis Sieb. Et Zucc. ), Dahurian larch ( Larix gmelinii Rupr. ), aspen-birch ( Populous davidiana Dode and Betula platyphylla Suk. ), hardwood ( Fraxinus mandshurica Rupr. , Juglans mandshurica Maxim. And Phellodendron amurense Rupr. ), Mongolian oak ( Quercus mongolica Fisch. ) and mixed deciduous (no dominant tree species) forests averaged 89, 196, 187, 245, 261 and 301 g C m−2 yr−1, respectively; those of RR averaged 424, 209, 628, 538, 524 and 483 g C m−2 yr−1, correspondingly; calculated contribution of RR to RS ( RC) varied from 52% in the larch forest to 83% in the pine forest. The annual flux of RR was strongly correlated to biomass of roots <0. 5 cm in diameter, while that of RH was weakly correlated to soil organic carbon concentration at A horizon. We concluded that vegetation type and associated carbon metabolisms of temperate forests should be considered in assessing and modeling RS components. The significant impacts of changed soil physical environments and substrate availability by plot trenching should be appropriately tackled in analyzing and interpreting measurements of RS components. [ABSTRACT FROM AUTHOR]

Scaling soil respiration ( RS), the major CO2 source to the atmosphere from terrestrial ecosystems, from chamber-based measurements to ecosystems requires studies on variations and correlations of RS from various biomes and across geographic regions. However, few studies on RS are available for Chinese temperate forest despite the importance of this forest in the national and global carbon budgets. In this study, we conducted 18-month RS measurements during 2004–2005 in six temperate forest types, representing the typical secondary forest ecosystems across various site conditions in northeastern China: Mongolian oak ( Quercus mongolica Fisch.), aspen-birch ( Populous davidiana Dode and Betula platyphylla Suk.), mixed deciduous (no dominant tree species), hardwood (dominated by Fraxinus mandshurica Rupr., Juglans mandshurica Maxim., and Phellodendron amurense Rupr.) forests, Korean pine ( Pinus koraiensis Sieb. et Zucc.) and Dahurian larch ( Larix gmelinii Rupr.) plantations. Our specific objectives were to: (1) explore relationships of RS against soil temperature and water content for the six forest ecosystems, (2) quantify annual soil surface CO2 flux and its relations to belowground carbon storage, (3) examine seasonal variations in RS and related environmental factors, and (4) quantify among- and within-ecosystem variations in RS. The RS was positively correlated to soil temperature in all forest types, and was significantly influenced by the interactions of soil temperature and water content in the pine, larch, and mixed deciduous forests. The sensitivity of RS to soil temperature at 10 cm depth ( Q10) ranged from 2.61 in the oak forest to 3.75 in the aspen-birch forests. The Q10 tended to increase with soil water content until reaching a threshold, and then decline. The annual RS for the larch, pine, hardwood, oak, mixed deciduous, and aspen-birch forests averaged 403, 514, 781, 785, 786, and 813 g C m−2 yr−1, respectively. The annual RS of the broadleaved forests was 72% greater than that of the coniferous forests. The annual RS was positively correlated to soil organic carbon (SOC) concentration at O horizon ( R 2=0.868) and total biomass of roots <0.5 cm in diameter ( R 2=0.748). The coefficient of variation (CV) of RS among forest types averaged 25% across the 18-month measurements. The CV of RS within plots varied from 20% to 27%, significantly ( P<0.001) greater than those among plots (9–15%), indicating the importance of the fine-scaled heterogeneity in RS. This study emphasized that variations in soil respiration and potential sampling bias should be appropriately tackled for accurate soil CO2 flux estimates. [ABSTRACT FROM AUTHOR]

Carbonaceous components are major components of PM 1 , which have a significant impact on climate change, air quality and human health. However, the secondary formation and source analysis of carbonaceous components in PM 1 are still unclear. Therefore, in order to study the secondary formation and sources of carbonaceous components in PM 1 , PM 1 samples were collected in Chengdu, a typical city located in southwest of China, from 2018 to 2019. The concentrations of organic carbon (OC), elemental carbon (EC) and isotopic compositions of carbon (δ13C) in PM 1 were determined using a thermal/optical carbon analyzer and elemental analyzer-isotope ratio mass spectrometer. In addition, the δ13C values from relevant potential sources (C3 plants, C4 plants, vehicle exhaust and coal) were also determined. The results showed that the annual average concentrations of OC and EC in PM 1 in Chengdu were 6.43 ± 3.30 μg·m−3 and 1.99 ± 0.98 μg·m−3, accounting for 13.83% and 4.28% of the PM 1 mass concentration, respectively. The concentrations of OC in PM 1 ranked in the order of winter > summer > spring > autumn, while the concentrations of EC varied in the order of winter > spring > autumn > summer. The concentrations of OC and EC in PM 1 reached the maximum in winter, mainly due to the special meteorological conditions and significantly higher pollutant emissions. The correlations of OC and EC were higher in spring, autumn and winter, and lower in summer. It showed that OC and EC might have the same sources in spring, autumn and winter, while the sources of OC and EC were relatively complex in summer. The annual average concentration of secondary organic carbon (SOC) in PM 1 was 2.23 ± 1.22 μg·m−3. The concentrations of SOC were higher in autumn and winter and lower in spring and summer. The special meteorological conditions and significantly higher pollutant emissions are important reasons for the higher SOC concentrations in winter. On the other hand, the low temperature in winter can also promote the formation of SOC. The results of carbon isotopic compositions indicated that the carbonaceous components in PM 1 were mainly derived from vehicle exhaust (52.4%), C3 plants combustion (26.2%), coal burning (16.2%) and C4 plants combustion (5.2%). The findings help to deepen the understanding of the secondary formation and sources of carbonaceous components in PM 1 and provide theoretical guidance for environmental management. [Display omitted] • The concentrations of OC and EC in PM 1 reached the maximum in winter. • OC and EC might have the same sources in spring, autumn and winter. • The concentrations of SOC were higher in autumn and winter. • The contribution ratios of vehicle exhaust exceeded 50% in all four seasons. [ABSTRACT FROM AUTHOR]

Background: Colorectal surgery is associated with high rates of surgical site infection (SSI). We investigated SSI in radical resection of colon or rectal carcinoma and its epidemiological distribution in 26 hospitals in China., Methods: We conducted prospective surveillance of patients who underwent radical resection of colon or rectal carcinoma in 26 selected hospitals from January 2015 to June 2016.An information system monitored all of the surgical inpatients. Infection control professionals observed the inpatients with suspected SSI who had been screened by the system at the bedside. The infection status of the incisions was followed up by telephone 1 month after the operation., Results: In total, 5729 patients were enrolled for the two operations; SSIs occurred in 206 patients, and the infection rate was 3.60%. The incidence of SSI after radical resection of rectal carcinoma (5.12%; 119/2323) was 2.1 times higher than that after radical resection of colon carcinoma (2.55%; 87/3406) (P < 0.0001). Additionally, in the colon versus rectal groups, the rate of superficial incisional SSI was 0.94% versus 2.28% (P < 0.0001), the rate of deep incisional SSI was 0.56% versus 1.11% (P = 0.018), and the rate of organ space SSI was 1.06% versus 1.72% (P = 0.031), respectively. The most common pathogens causing SSIs after radical resection of colon carcinoma were Escherichia coli (21/38) and Pseudomonas aeruginosa (5/38). Escherichia coli (24/65) and Enterococcus spp. (14/65) were the two most common pathogens in the rectal group. The multivariate logistic regression analysis showed that only the operating time and number of hospital beds were common independent risk factors for SSIs after the two types of surgery., Conclusion: This multicenter study showed that there were significant differences in the incidence of SSIs, three types of SSIs, and some risk factors between radical resection of colon carcinoma and rectal carcinoma.

Contamination of soil and water with fluorine (F) leached from phosphogypsum (PG) stacks is a global environmental issue. Millions of tons of PG is produced each year as a by-product of fertilizer manufacture, and in China, weathering is exacerbated by acid rain. In this work, column leaching experiments using simulated acid rain were run to evaluate the mobility of F and the impact of weathering on native bacterial community composition in PG. After a simulated summer rainfall, 2.42-3.05 wt% of the total F content of PG was leached and the F concentration in leachate was above the quality standard for surface water and groundwater in China. Acid rain had no significant effect on the movement of F in PG. A higher concentration of F was observed at the bottom than the top section of PG columns suggesting mobility and reprecipitation of F. Throughout the simulation, the PG was environmentally safe according the TCLP testing. The dominant bacteria in PG were from the Enterococcus and Bacillus genus. Bacterial community composition in PG leached by simulated acid rain (pH 3.03) was more abundant than at pH 6.88. Information on F mobility and bacterial community in PG under conditions of simulated rain is relevant to management of environmental risk in stockpiled PG waste.

Objective: We aimed to determine upright heart rate and blood pressure (BP) changes to suggest diagnostic criteria for postural orthostatic tachycardia syndrome (POTS) and orthostatic hypertension (OHT) in Chinese children., Methods: In this cross-sectional study, 1449 children and adolescents aged 6-18 years were randomly recruited from two cities in China, Kaifeng in Henan province and Anguo in Hebei province. They were divided into two groups: 844 children aged 6-12 years (group I) and 605 adolescents aged 13-18 years (group II). Heart rate and BP were recorded during an active standing test., Results: 95th percentile (P(95)) of δ heart rate from supine to upright was 38 bpm, with a maximum upright heart rate of 130 and 124 bpm in group I and group II, respectively. P(95) of δ systolic blood pressure (SBP) increase was 18 mm Hg and P(95) of upright SBP was 132 mm Hg in group I and 138 mm Hg in group II. P(95) of δ diastolic blood pressure (DBP) increase was 24 mm Hg in group I and 21 mm Hg in group II, and P(95) of upright DBP was 89 mm Hg in group I and 91 mm Hg in group II., Conclusions: POTS is suggested when δ heart rate is ≥ 38 bpm (for easy memory, ≥ 40 bpm) from supine to upright, or maximum heart rate ≥ 130 bpm (children aged 6-12 years) and ≥ 125 pm (adolescents aged 13-18 years), associated with orthostatic symptoms. OHT is suggested when δ SBP (increase) is ≥ 20 mm Hg, and/or δ DBP (increase) ≥ 25 mm Hg (in children aged 6-12 years) or ≥ 20 mm Hg (in adolescents aged 13-18 years) from supine to upright; or upright BP ≥ 130/90 mm Hg (in children aged 6-12 years) or ≥ 140/90 mm Hg (in adolescents aged 13-18 years)., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)