Although much attention has been paid to the mercury pollution in China, limited field studies have been conducted to explore the atmospheric behavior of mercury. To investigate the temporal ...variation and long-range transport of atmospheric gaseous elemental mercury (GEM or Hg(0)), the GEM measurements covering four different seasons were performed at a coastal/rural site of the Yellow Sea downwind of East China. Hourly mean concentrations of GEM measured by RA–915+ mercury analyzer over the entire study (four different time periods between July 2007 and May 2009) were 2.31 ± 0.74 ng m
−3 with a range of 1.12–7.01 ng m
−3. The results showed moderate seasonal variations with high levels in cold seasons (winter: 2.53 ± 0.77 ng m
−3 and spring: 2.34 ± 0.54 ng m
−3) and low levels in warm seasons (summer: 2.28 ± 0.82 ng m
−3 and fall: 2.16 ± 0.84 ng m
−3). Over the each campaign a diurnal variation of GEM was observed consistently with peak levels in daytime and low levels in late night and early morning. The pollution rose and NOAA–HYSPLIT back-trajectory model analyses indicated that the elevated GEM was transported to the sampling site from the regional sources of East China and Korea peninsula–Japan. Air masses originated from the East China Sea and the regions of Continental East Asia with low emission strengths of atmospheric mercury (e.g., the east Russia, the north Inner Mongolia and the Bohai Sea) showed the decreased GEM levels.
► Elevated GEM levels were observed at a coastal/rural site downwind of East China. ► GEM showed high levels in cold seasons and low levels in warm seasons. ► GEM showed peak levels in daytime and low levels in late night and early morning. ► Complicated patterns of GEM transport from different source regions were recorded.
The pattern of air–surface gaseous mercury (mainly Hg(0)) exchange in the Qinghai–Tibet Plateau (QTP) may be unique because this region is characterized by low temperature, great temperature ...variation, intensive solar radiation, and pronounced freeze–thaw process of permafrost soils. However, the air–surface Hg(0) flux in the QTP is poorly investigated. In this study, we performed field measurements and controlled field experiments with dynamic flux chambers technique to examine the flux, temporal variation and influencing factors of air–surface Hg(0) exchange at a high-altitude (4700 m a.s.l.) and remote site in the central QTP. The results of field measurements showed that surface soils were the net emission source of Hg(0) in the entire study (2.86 ng m−2 h−1 or 25.05 µg m−2 yr−1). Hg(0) flux showed remarkable seasonality with net high emission in the warm campaigns (June 2014: 4.95 ng m−2 h−1; September 2014: 5.16 ng m−2 h−1; and May–June 2015: 1.95 ng m−2 h−1) and net low deposition in the winter campaign (December 2014: −0.62 ng m−2 h−1) and also showed a diurnal pattern with emission in the daytime and deposition in nighttime, especially on days without precipitation. Rainfall events on the dry soils induced a large and immediate increase in Hg(0) emission. Snowfall events did not induce the pulse of Hg(0) emission, but snowmelt resulted in the immediate increase in Hg(0) emission. Daily Hg(0) fluxes on rainy or snowy days were higher than those of days without precipitation. Controlled field experiments suggested that water addition to dry soils significantly increased Hg(0) emission both on short (minutes) and relatively long (hours) timescales, and they also showed that UV radiation was primarily attributed to Hg(0) emission in the daytime. Our findings imply that a warm climate and environmental change could facilitate Hg release from the permafrost terrestrial ecosystem in the QTP.
The precise and visual analysis of solid waste recycling in concrete construction engineering is critical for the development of ecological civilization and for the secure supply of resources. This ...research makes a bibliometric analysis of the solid waste application in concrete construction engineering from 2000 to 2021 based on the Web of Science. The global bibliometric status, current research focus and future directions were used to indicate the global development of solid waste recycling in concrete construction engineering. The most reused solid wastes and most solid waste productive regions were concluded with this bibliometric analysis. China is far ahead of other countries in solid waste recycling in all aspects and heavy metal is one of the most prominent solid waste themes in China. By analyzing the most studied solid waste, fly ash appears to be the most popular and is widely used; half of the top ten-cited papers are correlated with it.
Micro-surfacing (MS), made of emulsified asphalt, is the most commonly used preventive maintenance technology in asphalt pavement. However, the studies on profile features of MS based on aggregate ...morphology are few. This study evaluated the profile features of MS and its effect on skid resistance. The aggregate morphologies were first characterized and modified emulsified asphalt was prepared. The three-dimensional profile features of four kinds of MS samples were captured by laser texture scanner. Results illustrate that steel slag aggregate can be used to enhance the skid resistance of pavement surface and bring about larger profile indexes than basalt and limestone due to its angularity index and flatness values. Further aging of steel slag to eliminate free calcium oxide (f-CaO) is recommended before being used in pavement surface layer.
Recent studies demonstrated that subtropical forest in China was considered as a large pool of atmospheric mercury and soils of forested watershed is a large reservoir of atmospherically deposited ...mercury. However, forest ecosystems not only act as sinks but also as sources of previously deposited mercury emitted back to the atmosphere. In this study a field controlled method was performed in Tieshanping National Forest Park (TNFP) to identify the effects of the most important parameters that controlled mercury emissions from soil surfaces, including chamber flushing flow turnover times (TOTs), soil water content and watering, total gaseous mercury (TGM) in air and understory. Flushing flow rates significantly affected the calculation of mercury flux and the optimal TOTs were 0.94min in the forest. TGM in atmosphere was significantly inhibited mercury emission from soils, and the deposited mercury was not absorbed firmly by the soils in a short time and emitted back to atmosphere rapidly when TGM concentration decreased. Higher soil moisture reduced the emission of mercury and initial watering produces a spike in the mercury emissions due to the interstitial soil gas mercury displaced by infiltrating water physically. However, subsequent watering was reducing the fluxes, because surface soil was saturated and soil pores were blocked by water film and inhibited the soil mercury emission. Soils under the understory had a higher mercury concentrations and deep organic layers. However, the fluxes of soil under the understory significantly were inhibited in daytime because solar radiation was blocked by the understory and the higher litter layer.
•Major parameters were investigated on mercury fluxes in subtropical forest in China.•The optimal sampling turnover time is 0.94min.•Higher TGM concentration significantly suppressed soil mercury emission.•Watering increased emissions of soil mercury, but subsequent watering inhibited soil mercury emission.•Understory significantly inhibited mercury emissions from forest soils in daytime.
In this research, the durability of skid resistance during the ice melting process with temperature increasing from -5 °C to 10 °C was characterized by means of a British Pendulum Skid Tester. Four ...types of pavement surfaces were prepared and tested. The difference between two antiskid layers prepared with bitumen emulsion was the aggregate. The detailed angularity and form 2D index of fine aggregates used for antiskid surfaces, characterized by means of the Aggregate Image Measure System (AIMS) with micro image analysis methods, were then correlated with British Pendulum Number (BPN) values. Results indicate that skid resistance has the lowest value during the ice-melting process. The investigated antiskid layers can increase the surface friction during icy seasons. In icy conditions, the skid resistance behavior first worsens until reaches the lowest value, and then increases gradually with increasing temperature. Results from ice-melting conditions on four investigated pavement surfaces give the same temperature range where there will be lowest skid resistance. That temperature range is from 3 °C to 5 °C. A thicker ice layer will result in a lower skid resistance property and smaller "lowest BPN".
Small extracellular vesicles (sEVs) have great potential as new biomarkers in liquid biopsy. However, due to the limitations of sEVs extraction and component analysis procedures, further clinical ...applications of sEVs are hampered. Carcinoembryonic antigen (CEA) is a commonly used broad-spectrum tumor marker that is strongly expressed in a variety of malignancies.
In this study, CEA
sEVs were directly separated from serum using immunomagnetic beads, and the nucleic acid to protein ultraviolet absorption ratio (NPr) of CEA
sEVs was determined. It was found that the NPr of CEA
sEVs in tumor group was higher than that of healthy group. We further analyzed the sEV-derived nucleic acid components using fluorescent staining and found that the concentration ratio of double-stranded DNA to protein (dsDPr) in CEA
sEVs was also significantly different between the two groups, with a sensitivity of 100% and a specificity of 41.67% for the diagnosis of pan-cancer. The AUC of dsDPr combined with NPr was 0.87 and the ACU of dsDPr combined with CA242 could reach 0.94, showing good diagnostic performance for pan-cancer.
This study demonstrates that the dsDPr of CEA
sEVs can effectively distinguish sEVs derived from tumor patients and healthy individuals, which can be employed as a simple and cost-effective non-invasive screening technology to assist tumor diagnosis.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Dissolved gaseous mercury (DGM, largely Hg(0)) in coastal seawater and gaseous elemental mercury (GEM or Hg(0)) in the atmosphere were simultaneously measured on the coast of the Yellow Sea, China in ...four different seasons (2008–09). Mean concentrations (±SD) of DGM and GEM over the study period were 34.0
±
26.1
pg
L
−1 and 2.55
±
0.98
ng
m
−3, respectively. DGM concentrations and the degree of DGM saturation (
S
a) exhibited distinct seasonal variation with the order of summer (DGM: 69.0
±
23.3
pg
L
−1,
S
a: 11.00
±
5.92)
>
fall (27.0
±
16.4
pg
L
−1, 3.50
±
2.60)
>
spring (23.0
±
8.7
pg
L
−1, 2.00
±
0.98)
>
winter (16.0
±
6.0
pg
L
−1, 0.96
±
0.39). Under typical meteorological condition with low wind speed and intensive solar radiation in warm seasons, DGM usually exhibited the clear diurnal variation with elevated levels around noon and low levels in morning and afternoon. The diurnal and seasonal variation of DGM indicated the importance of photochemical DGM formation in the seawater. A consistent low DGM levels in high wind speed condition suggested that the biological activity probably influenced the DGM formation. There was no significant correlation between DGM and total mercury (THg), reactive mercury (RHg), dissolved organic carbon (DOC) in the seawater, indicating that THg/RHg and DOC might be not the controlling factors for the DGM formation in our study region. Based on the data of DGM and GEM and a two-layer gas exchange model, Hg(0) fluxes (in the unit of ng
m
−2
h
−1) at air–sea interface were 0.51
±
1.29 over the entire study period with 0.89
±
1.84 in fall, 0.88
±
1.38 in summer, 0.32
±
0.71 in spring, and −0.06
±
0.64, a slightly net Hg(0) deposition rate, in winter, respectively.
The melamine diborate (C3N6H6·2H3BO3) supramolecules are very promising precursor to boron nitride (BN) fibers in addition to polyborazane. However, deep understanding on the structure evolution from ...C3N6H6·2H3BO3 into BN remains rare, thus limiting the precise regulations on the constituents of BN fibers and their performance improvement. Herein, we provided a molecular-scale insight into this evolution process. Specifically, dehydration of boric acid and condensation of melamine generated the boron oxide oligomer tangled with melamine condensates in first stage, then cross-linking of the two parts gave formation of the polymer network, afterwards decomposition of triazine ring promoted the nitridation of boron oxide to evolve into the BN structure, and the structure rearrangement facilitated crystallization in final. This transformation mechanism could be used to instruct the regulation on the constituents of BN fibers through controlling pyrolyzing reactions of C3N6H6·2H3BO3, and to further realize performance optimization.
Dysregulation of transfer RNA (tRNA)-derived small noncoding RNA (tsRNA) signatures in human serum has been found in various diseases. Here, we determine whether the signatures of tsRNAs in serum can ...serve as biomarkers for diagnosis or prognosis of systemic lupus erythematosus (SLE).
Initially, small RNA sequencing was employed for the screening serum tsRNAs obtained from SLE patients, followed by validation with TaqMan probe-based quantitative reverse transcription-PCR (RT-PCR) assay. Receiver operating characteristic (ROC) curve analysis was used to assess the diagnostic efficacy. The biological functions of tsRNAs were identified by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) assay.
We first analyzed tsRNA signatures in SLE serum and identified that tRF-His-GTG-1 was significantly upregulated in SLE serum. The combination of tRF-His-GTG-1 and anti-dsDNA could serve as biomarkers for diagnosing SLE with a high area under the curve (AUC) of 0.95 (95% CI = 0.92-0.99), sensitivity (83.72%), and specificity (94.19%). Importantly, the noninvasive serum tRF-His-GTG-1 could also be used to distinguish SLE with LN or SLE without LN with AUC of 0.81 (95% CI, 0.73-0.88) and performance (sensitivity 66.27%, specificity 96.15%). Moreover, the serum tsRNA is mainly secreted
exosome and can directly target signaling molecules that play crucial roles in regulating the immune system.
In this study, it has been demonstrated for the first time that serum tsRNAs can be employed as noninvasive biomarkers for the efficient diagnosis and prediction of nephritis in SLE.
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