Dynamic characteristics and evolution laws of underground brine in Mahai salt lake of Qaidam Basin during mining process.

In the late stage of underground brine mining in salt lakes, the method of injecting fresh water is often used to extract the salt from the brine storage medium. This method of freshwater displacement breaks the original water-rock equilibrium and changes the evolution process of the original underground brine. To explore the mechanism of salt release in saline water-bearing media under conditions of relatively fresh lake water dissolution, this paper analyzes the changes in the chemical parameters of brine from 168 sampling points in the Mahai salt lake in the Qaidam Basin at three stages (before exploitation, during exploitation, and late exploitation) by correlation analysis, ion ratio analysis, and other methods and investigate the variations in porosity and the evolution laws of brine. The results show that the changes in the main ion content and brine mineralization during the exploitation process are small. The changes in Ca2+ content are significant due to the low solubility of calcium minerals, the precipitation of gypsum during the mixing process, and the adsorption of cations by alternating with Ca2+. Primary intergranular pore skeletons are easily corroded to form secondary pores, which increase the geological porosity. Na+ and Cl- are the dominant ions in the brine in the study area, but the concentration of Ca2 + decreased significantly under the influence of mining, by 41.7% in the middle period and 24.5% in the late period. The correlation between Ca2+ and salinity changes significantly in different mining stages, and the reason for the decrease of Ca2+ may be due to the influence of mineral dissolution, mixing, and anion-cation exchange. The porosity of the layer in the study area showed the opposite trend of Ca2+, and the porosity increased first and then decreased. The innovation of this paper lies in analyzing the reasons and mechanisms of the disturbance of artificial dissolution mining on stratum structure by comparing the hydrochemical characteristics and porosity of underground brine storage media in three different mining stages. The research in this paper provides a theoretical basis for the calculation of brine resource reserves and the sustainable development of underground brine in salt lake areas.

Assessment of heavy metal accumulation and potential risks in surface sediment of estuary area: A case study of Dagu river.

Soil/sediment samples of four different land types were collected from aquaculture land, farmland, industrial land and river bottom sediment in the estuary area of Dagu River. The contents of Cr, Cu, Zn, As, Cd and Pb in 0-30 cm inner surface samples were detected, and the distribution characteristics of heavy metal content in surface soil/sediment of different land use types in the estuary area were analyzed. Local accumulation index method, potential risk index evaluation method and principal component analysis method were used to analyze the pollution status and sources of heavy metals. The results showed that the heavy metal accumulation levels in soil and sediment samples in the study area were As > Cd > Cu > Pb > Zn > Cr, and the heavy metal content exceeded the soil background value in Shandong Province, but the potential risks were all in a low risk state. The main sources of Cr, Zn and As are transportation sources and natural sources, while the main sources of Cd and Pb are agricultural.

Resolving Ultraviolet-Visible Spectra for Complex Dissolved Mixtures of Multitudinous Organic Matters in Aerosols.

Light-absorbing organic aerosols, referred to as brown carbon (BrC), play a vital role in the global climate and air quality. Due to the complexity of BrC chromophores, the identified absorbing substances in the ambient atmosphere are very limited. However, without comprehensive knowledge of the complex absorbing compounds in BrC, our understanding of its sources, formation, and evolution mechanisms remains superficial, leading to great uncertainty in climatic and atmospheric models. To address this gap, we developed a constrained non-negative matrix factorization (NMF) model to resolve the individual ultraviolet-visible spectrum for each substance in dissolved organic aerosols, with the power of ultrahigh-performance liquid chromatography-diode array detector-ultrahigh-resolution mass spectrometry (UHPLC-DAD-UHRMS). The resolved spectra were validated by selected standard substances and validation samples. Approximately 40,000 light-absorbing substances were recognized at the MS1 level. It turns out that BrC is composed of a vast number of substances rather than a few prominent chromophores in the urban atmosphere. Previous understanding of the absorbing feature of BrC based on a few identified compounds could be biased. Weak-absorbing substances missed previously play an important role in BrC absorption when they are integrated due to their overwhelming number. This model brings the property exploration of complex dissolved organic mixtures to a molecular level, laying a foundation for identifying potentially significant compositions and obtaining a comprehensive chemical picture.

Distribution, sources, and ecological risk assessment of polychlorinated biphenyls (PCBs) in the estuary of Dagu River, China.

Four different types of 0-30 cm soil/sediment samples were collected from aquaculture land, farmland, industrial land and river bottom sediment in the estuary area of Dagu River, and the pollution status and sources of 7 PCB congeners were analyzed. The results showed that the mean values of Σ7PCBs in soil/sediments of different land use types were 5.01 ng g-1 dw for industrial land, 3.6 ng g-1 dw for estuarine sediments, 2.09 ng g-1 dw for farmland soil and 1.78 ng g-1 dw for farming land. All samples were at low pollution levels and pose little ecological risks. PCBs in the samples are mainly comprised of highly chlorinated biphenyls, and their content decreases gradually with increasing sampling depth. Based on the principal component analysis, it is concluded that the main source of PCBs in the study area is shipping activities, in addition to atmospheric transport and sedimentation sources.

Hyalinising clear cell carcinoma of the lung: A case report and review of literature.

BACKGROUND: Hyalinising clear cell carcinoma (HCCC) of the lung is a rare tumor, with only 12 reported cases. To improve the differential diagnosis, the aim of this study was to clarify the clinicopathological characteristics, immunophenotype, and molecular characteristics of HCCC of the lung and relate these to prognosis. METHODS: Sections of HCCC of the lung were collected from a patient for pathological observation, immunohistochemistry, histochemistry, and fluorescence in situ hybridization; the clinical, pathological, and molecular characteristics were compared with those reported in the literature. RESULTS: The tumor had a well-demarcated border nodule with a maximal diameter of 2.5 cm. Microscopic findings showed either clear or eosinophilic cytoplasm in the tumor cells. Growth was predominantly in the sheets, nests, and trabeculae in a background of hyalinised, fibrotic stroma, and mucus degeneration. Immunohistochemistry showed that the tumor cells expressed cytokeratin 7, P63, P40, CK5/6, Pan Cytokeratin (PCK), and epithelial membrane antigen, whereas they were negative for thyroid transcription factor-1, napsin A, CD10, vimentin, and smooth muscle actin. The Ki67 proliferation index was 5%. The tumor was positive for both period acid-Schiff (PAS) and Alcian blue-PAS, with a small amount of mucus staining positive for PAS-diastase. Fluorescence in situ hybridization revealed Ewing sarcoma breakpoint region 1 rearrangement and Ewing sarcoma breakpoint region 1-activating transcription factor 1 fusion. CONCLUSIONS: HCCC is a low-grade carcinoma with excellent prognosis. Tumour necrosis may be a potential risk factor for recurrence and metastasis. Our review of reported cases suggests that regional lymph node dissection combined with lobectomy is a safer treatment than only lobectomy for HCCC of the lung.

Secondary organic aerosol formation in China from urban-lifestyle sources: Vehicle exhaust and cooking emission.

An increasing number of people tend to live in cities, where they suffer from serious air pollution from anthropogenic sources. Vehicle exhaust and cooking emission are closely related to daily life of urban residents, and could be defined as "urban-lifestyle sources". The primary emissions of urban-lifestyle sources tend to form abundant secondary organic aerosols (SOA) through complicated atmospheric chemistry processes. The newly formed SOA is a kind of complex mixture and causes considerable health effects with high uncertainty. Most studies focus on formation pathway, mass growth potential and chemical feature of urban-lifestyle SOA under simple laboratory conditions. Few studies have measured the urban-lifestyle SOA in ambient air, let alone verified laboratory findings under complicated atmospheric conditions. In this work, we established a new method that combined laboratory simulation and field observation, which quantified the urban-lifestyle SOA with high time resolution under the real atmospheric condition. The complex SOA was measured and resolved by a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). The multilinear engine model (ME-2) and multilinear correction methods were used to apply laboratory results into ambient SOA apportionment. It was found that the vehicle source dominated the SOA formation during the diurnal photochemical process, and the SOA:POA ratio of vehicle source was about 1.4 times larger than that of cooking source. The vehicle emission may undergo an alcohol/peroxide & carboxylic acid oxidation pathway and form higher oxidized SOA, while the cooking emission may undergo an alcohol/peroxide oxidation pathway and form relatively lower oxidized SOA. The vehicle SOA and cooking SOA contributed 45.6 % and 24.8 % of OA during a local episode in 2021 winter of downtown Beijing. Our findings could not only provide a new way to quantify urban SOA but also demonstrate some laboratory hypotheses, conducing to understand its ambient contributions, chemical features, and environmental effects.

Canopy structure: An intermediate factor regulating grassland diversity-function relationships under human disturbances.

Grasslands are one of the largest coupled human-nature terrestrial ecosystems on Earth, and severe anthropogenic-induced grassland ecosystem function declines have been reported recently. Understanding factors influencing grassland ecosystem functions is critical for making sustainable management policies. Canopy structure is an important factor influencing plant growth through mediating within-canopy microclimate (e.g., light, water, and wind), and it is found coordinating tightly with plant species diversity to influence forest ecosystem functions. However, the role of canopy structure in regulating grassland ecosystem functions along with plant species diversity has been rarely investigated. Here, we investigated this problem by collecting field data from 170 field plots distributed along an over 2000 km transect across the northern agro-pastoral ecotone of China. Aboveground net primary productivity (ANPP) and resilience, two indicators of grassland ecosystem functions, were measured from field data and satellite remote sensing data. Terrestrial laser scanning data were collected to measure canopy structure (represented by mean height and canopy cover). Our results showed that plant species diversity was positively correlated to canopy structural traits, and negatively correlated to human activity intensity. Canopy structure was a significant indicator for ANPP and resilience, but their correlations were inconsistent under different human activity intensity levels. Compared to plant species diversity, canopy structural traits were better indicators for grassland ecosystem functions, especially for ANPP. Through structure equation modeling analyses, we found that plant species diversity did not have a direct influence on ANPP under human disturbances. Instead, it had a strong indirect effect on ANPP by altering canopy structural traits. As to resilience, plant species diversity had both a direct positive contribution and an indirect contribution through mediating canopy cover. This study highlights that canopy structure is an important intermediate factor regulating grassland diversity-function relationships under human disturbances, which should be included in future grassland monitoring and management.

Does environmental uncertainty of enterprises aggravate the accrual anomaly in the stock market? Evidence from China.

Enterprises do not exist independently of the external environment, so uncertainty affects their earnings volatility and exacerbates the information asymmetry between internal and external stakeholders. As a major manifestation of capital market mispricing, the accrual anomaly is caused by investors' functional fixation on total surplus under information asymmetry. Against this backdrop, taking A-share listed companies in China from 2007 to 2019 as our research objects, this study explores the impact of environmental uncertainty on the accrual anomaly based on the information asymmetry and investor irrationality perspective. We find that environmental uncertainty enterprises facing exacerbates the accrual anomaly in the Chinese stock market, and internal control quality, state ownership and the media coverage will affect this impact. Furthermore, this study shows that there are three factors playing the mediating role in the effect, accounting information quality, investment growth and the investor attention. The results show that environmental uncertainty exacerbates the accrual anomaly driven by information manipulation, empire building and investor irrationality. Improving investor irrationality behavior and restraining the self-interest behavior of managers can help alleviate the mispricing of accruals caused by information asymmetry in psychology.

Aqueous secondary organic aerosol formation attributed to phenols from biomass burning.

Biomass burning emits large quantities of phenols, which readily partition into the atmospheric aqueous phase and subsequently may react to produce aqueous secondary organic aerosol (aqSOA). For the first time, we quantitatively explored the influence of phenols emitted from biomass burning on aqSOA formation in the winter of Beijing. A typical haze episode associated with significant aqSOA formation was captured. During this episode, aqueous-phase processing of biomass burning promoted aqSOA formation was identified. Furthermore, high-resolution mass spectrum analysis provided molecular-level evidence of the phenolic aqSOA tracers. Estimation of aqSOA formation rate (RaqSOA) with compiled laboratory kinetic data indicated that biomass-burning phenols can efficiently produce aqSOA at midday, with RaqSOA of 0.42 µg m-3 h-1 accounting for 15 % of total aqSOA formation rate. The results highlight that aqSOA formation of phenols contributes the haze pollution. This implies the importance of regional joint control of biomass burning to mitigate the heavy haze.

A preliminary study on the eco-environmental geological issue of in-situ oil shale mining by a physical model.

As traditional methods of oil shale production emitting high levels of pollutants, in-situ exploitation has aroused great concerns. In order to study the effect of in-situ pyrolysis products on the underground environment, an in-situ oil shale exploitation of underground environment impact laboratory simulation system was designed. Based on the hydrogeological condition of oil shale area in Nong'an City, a physical simulation test was conducted. It was found the temperature of surrounding layers continued to be perturbed after heating of the formation had stopped. The time during which the temperature was perturbed was about 4-5 times the heating period. During the simulation test, stray gas migration through fractures and faults was considered a mechanism for groundwater contamination. In the test, the maximum TOC content in aquifer was the value of 97.0 mg/L. The maximum total petroleum hydrocarbon (TPH) content of the simulated formation was 129 mg/kg after oil pyrolysis.

Current challenges of improving visibility due to increasing nitrate fraction in PM2.5 during the haze days in Beijing, China.

The annual mean PM2.5 mass concentration has decreased because of the stringent emission controls implemented in Beijing, China in recent years, whereas the nitrate NO3- mass fraction in PM2.5 increases gradually. Low-visibility events occur frequently even though PM2.5 pollution has been mitigated significantly, with the daily mean PM2.5 mass concentration mostly less than 75 µg/m3. In this study, the non-linear relationship was analyzed between atmospheric visibility and PM2.5 based on chemical composition from a two-year field observation. Our results showed that NO3- became the main constituent of PM2.5, especially during the haze pollution episodes. A localized parameterization scheme was proposed between the atmospheric extinction coefficient (σext) and major chemical constituents of PM2.5 by multiple linear regression (MLR). The contribution of NO3- to σext increased with increasing air pollution, and NO3- became the most important contributor for PM2.5 above 75 µg/m3. The visibility decreased with increasing NO3- mass fraction for the same PM2.5 mass concentration when PM2.5 was above 20 µg/m3. The hygroscopicity of PM2.5 increased with increasing mass fraction of hygroscopic NO3-. These results stressed the importance of reducing particulate NO3- and its precursors (for instance, NH3) through effective emission control measures as well as the tightening of PM2.5 standards to further improve air quality and visibility in Beijing.

[Responses of soil potential carbon/nitrogen mineralization and microbial activities to extreme droughts in a meadow steppe]. / 草甸草原土壤碳/氮矿化潜力及土壤微生物水分敏感性对极端干旱的响应.

The mineralization of soil carbon (C) and nitrogen (N) is a critical process in the cycling of C and N in terrestrial ecosystems, which is strongly controlled by water availability. In this study, we collected soil samples in a 3-year extreme drought experiment in a meadow steppe in Inner Mongolia, freeze-dried these samples, and measured the potential C and N mineralization rates and water sensitivity of soil microorganism by incubating soils under soil water contents (SWC) of 3%, 8%, 13%, 18%, 25% and 35%. The results showed that averaged across different SWC, the extreme drought treatment of reducing 66% precipitation in growing season significantly increased potential N mineralization rate by 14.2%, but did not affect the potential C mineralization. Extreme drought significantly increased soil microbial biomass N and soil dissolved organic C by 26.8% and 26.9%, respectively. In both the control (natural rainfall) and extreme drought treatment, the potential C and N mineralization and microbial biomass C and N increased with SWC in the incubation, which was possibly caused by the enhanced substrate diffusion. Extreme drought also promoted the initial pulse response of C mineralization, implying the enhanced microbial response to water availability. Extreme drought significantly reduced the ratio of the potential soil C mineralization to the potential N mineralization, suggesting that extreme drought might weak the coupling of soil C and N. Extreme drought could cause different responses to soil water availability between soil C and N cycling. Extreme drought could enhance microbial response to increasing water availability, weak coupling between soil C and N, with consequences on nutrient cycling and primary productivity in the meadow steppe of northern China.

The effect of hepatocellular carcinoma-associated fibroblasts on hepatoma vasculogenic mimicry.

Vasculogenic Mimicry (VM) is the main source of blood supply in the early stage of tumor growth. Carcinoma-associated fibroblasts (CAFs) are one of the most important host cells in the tumor microenvironment. Some studies have found that CAFs can promote tumor angiogenesis, but there are few reports on the relationship between CAFs and VM. Tissue samples were collected from 60 cases of hepatocellular carcinoma (HCC) and 10 persons with normal liver function. The relationship between VM expression and clinicopathologic features was analyzed. Furthermore, the relationship between VM expression and vimentin or α-SMA expression was analyzed. Primary culture of hepatocellular CAFs and the collection of conditioned media were carried out. The effects of hepatocellular CAF conditioned medium on the formation of VM and the levels of VM-related proteins and genes in MHCC-97H cells were studied. The positive rate of VM was 35.0% in HCC tissues. There was no VM expression in normal liver tissues. VM expression was related to tumor diameter, Edmondson grade, clinical stage, and liver cirrhosis. The expression of vimentin and α-SMA in VM-positive patients was higher than in VM-negative patients. Different concentrations of hepatocellular CAF conditioned medium could promote the formation of VM and increase the expression of VM-related genes and proteins (MMP2 and EphA2) in MHCC-97H cells. The results show that there was a significant correlation between VM formation and the expression of vimentin or α-SMA in HCC tissues. The conditioned medium of hepatocellular CAFs may promote VM formation and the expression of VM-related genes and proteins (MMP2 and EphA2) in hepatoma cell line MHCC-97H.

The influence of oil shale in situ mining on groundwater environment: A water-rock interaction study.

Oil shale samples were obtained from Nong'an oil shale ore-bearing area which was located in the southeastern uplift of Songliao basin, China. The XRD test for oil shale identified the minerals in it and a series of water-rock interaction experiment between oil shale-water and oil shale ash-water were carried out to the study the release of organic matter from groundwater during oil shale in-situ exploitation. The content of phenol, BTEX, TOC and TPH in oil shale and oil shale ash aqueous solution were determined. The phenol and TOC in oil shale aqueous solution were higher than that of oil shale ash aqueous solution, conversely, more BTEX and TPH were existed in oil shale ash aqueous solution. The reaction temperature had significant influence on phenol, TOC and TPH in oil shale aqueous solution, which was not obvious in oil shale ash aqueous solution. Besides, the TOC average content in oil shale aqueous solution gradually increased along with the reaction time. The results show that not only oil shale in situ mining process make groundwater organic pollution aggravate but also continuous pollution of groundwater caused by the residual oil shale ash still exist.

Levels and distribution of synthetic musks in farmland soils from the Three Northeast Provinces of China.

The levels and distribution of synthetic musks (ADBI, AHMI, ATII, HHCB, AHTN, MX and MK) were investigated in farmland soils from the Three Northeast Provinces of China. The total concentrations of SMs ranged from 2.40 ng/g to 12.2 ng/g (dry weight). HHCB and AHTN were the main pollutants that were detected in all samples, accounting for 99.35% of the total SMs. The hazard quotients were 0.0700 and 0.102 for AHTN and HHCB, respectively. Although the results indicate there is no serious environmental impact, the detection frequency of SMs in the farmland soil is high, which demonstrated that SMs are widely used in the Three Northeast Provinces of China. Therefore, more attention should be given to synthetic musks during environment monitoring and risk assessments for their bioaccumulation, lipophilicity and persistence.

DHS (trans-4,4'-dihydroxystilbene) suppresses DNA replication and tumor growth by inhibiting RRM2 (ribonucleotide reductase regulatory subunit M2).

DNA replication machinery is responsible for accurate and efficient duplication of the chromosome. Since inhibition of DNA replication can lead to replication fork stalling, resulting in DNA damage and apoptotic death, inhibitors of DNA replication are commonly used in cancer chemotherapy. Ribonucleotide reductase (RNR) is the rate-limiting enzyme in the biosynthesis of deoxyribonucleoside triphosphates (dNTPs) that are essential for DNA replication and DNA damage repair. Gemcitabine, a nucleotide analog that inhibits RNR, has been used to treat various cancers. However, patients often develop resistance to this drug during treatment. Thus, new drugs that inhibit RNR are needed to be developed. In this study, we identified a synthetic analog of resveratrol (3,5,4'-trihydroxy-trans-stilbene), termed DHS (trans-4,4'-dihydroxystilbene), that acts as a potent inhibitor of DNA replication. Molecular docking analysis identified the RRM2 (ribonucleotide reductase regulatory subunit M2) of RNR as a direct target of DHS. At the molecular level, DHS induced cyclin F-mediated down-regulation of RRM2 by the proteasome. Thus, treatment of cells with DHS reduced RNR activity and consequently decreased synthesis of dNTPs with concomitant inhibition of DNA replication, arrest of cells at S-phase, DNA damage, and finally apoptosis. In mouse models of tumor xenografts, DHS was efficacious against pancreatic, ovarian, and colorectal cancer cells. Moreover, DHS overcame both gemcitabine resistance in pancreatic cancer and cisplatin resistance in ovarian cancer. Thus, DHS is a novel anti-cancer agent that targets RRM2 with therapeutic potential either alone or in combination with other agents to arrest cancer development.

Differences in silencing of mismatched targets by sliced versus diced siRNAs.

It has been reported that the two major types of RNA interference triggers, the classical Dicer-generated small RNAs (siRNAs), which function with all members of the Argonaute (Ago) protein family in mammals, and the Ago2-sliced small RNAs (sli-siRNAs), which function solely through Ago2, have similar potency in target cleavage and repression. Here, we show that sli-siRNAs are generally more potent than siRNAs in silencing mismatched targets. This phenomenon is usually more apparent in targets that have mismatched nucleotides in the 3' supplementary region than in targets with mismatches in the seed region. We demonstrate that Ago2 slicer activity is a major factor contributing to the greater silencing efficiency of sli-siRNA against mismatched targets and that participation of non-slicing Agos in silencing mismatched siRNA targets may dilute the slicing ability of Ago2. The difference in length of the mature guide RNA used in sli-RISCs and si-RISCs may also contribute to the observed difference in knockdown efficiency. Our data suggest that a sli-siRNA guide strand is likely to have substantially stronger off-target effects than a guide strand with the same sequence in a classical siRNA and that Dicer and non-slicing Agos may play pivotal roles in controlling siRNA target specificity.

Enhanced removal of bisphenol-AF by activated carbon-alginate beads with cetyltrimethyl ammonium bromide.

Adsorption removal of bisphenol-AF (BPAF) from aqueous solutions by synthesized activated carbon-alginate beads (AC-AB) with cetyltrimethyl ammonium bromide (CTAB) has been studied using two ways. The traditional method (two-step) first synthesized CTAB-modified AC-AB (AC-AB-CTAB), then used it to remove BPAF by adsorption. And one-step method dispersed AC-AB and CTAB in wastewater, followed by the removal of BPAF accompanied with the synthesis of AC-AB-CTAB. The one-step method showed a better performance than the two-step method, achieving a maximum removal of BPAF with 284.6mg/g. Kinetic studies and adsorption isotherms indicated that adsorption process of BPAF on AC-AB by the one-step method could be expressed by a pseudo-second-order model and a Dubinin-Ashtakhov (D-A) isotherm, respectively. The effects of pH, ionic strength, and inorganic ions on BPAF adsorption were also investigated. Furthermore, hydrophobic interactions, hydrogen bonds, and π-π electron donor-acceptor (EDA) interactions were discussed to explain the enhanced adsorption behavior of BPAF on AC-AB with CTAB. The findings verified the effectiveness of AC-AB for the removal of BPAF from wastewater and its high stability within five regeneration cycles.