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To investigate the health risks of typical soil heavy metals to surrounding residents of industrial land in the urban-rural area of Liuquan Town, Xigu District, Lanzhou City, China. The contents of As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn were analyzed using an X-ray fluorescence spectrometer. Non-carcinogenic and carcinogenic risks of the heavy metals to children and adults were evaluated. Results showed higher soil Hg, Pb, and Zn contents in the study area than the corresponding background values of Gansu Province. The Hg pollution was the most serious, showing higher contents than the background water at 56.41% of the soil sampling sites. As, Cr, Cu, Ni, and Pb showed normal distributions, while Cd, Hg, and Zn exhibited skewed distributions. Hg and Cd showed the highest coefficients of variation of 0.966 and 0.548, respectively. Health risk evaluation results showed higher total non-carcinogenic risk (HI) and total carcinogenic risk (TCR) for children than those for adults by 5.411 and 2.156, respectively, indicating children are more susceptible to non-carcinogenic and carcinogenic risks. In addition, As, Cr, and Pb were the main contributors to the non-carcinogenic risk, while As and Cr were the main contributors to the carcinogenic risk. [ABSTRACT FROM AUTHOR]

Taiyuan Formation limestone groundwater is the main aquifer threatening the safety of exploration under deep mining in the Huaibei coalfield. Therefore, acknowledging the hydrochemical characteristics and constructing reverse hydrogeochemical modeling are crucial for predicting and preventing mine water hazards. In this study, the mathematical statistical analysis, Piper threeline diagram, Gibbs diagram, ion proportional relationship, Chlorine-Alkali index, and the reverse hydrogeochemical modeling were employed for determining the hydrochemical characteristics and the formation mechanism. The results revealed that the hydrochemical types of groundwater samples were SO4.Cl-Ca.Mg and HCO3.Cl-Na, respectively. The water-rock interactions were primarily influenced by the leaching and the cation exchange, with these processes being more intense in the eastern region. Through reverse hydrogeochemical modeling, the water-rock interactions in the process of groundwater runoff were quantitatively verified, viz. the calcite and the dolomite were saturated and precipitating, while the gypsum and the halite were unsaturated and still dissolving. Furthermore, the simulations of mass transfer in groundwater runoff indicated that the dissolution and the leaching of gypsum, dolomite and halite, positive ion exchange, the precipitation of calcite, and the dissolution of CO2 gas predominantly occurred along four simulated flow paths. These results offered a scientific foundation for the prevention and controlling of mine water hazards in deep mining contexts. [ABSTRACT FROM AUTHOR]

Microcystis aeruginosa is a common microalgae in nature. It is also the dominant algae species to form freshwater blooms. Water bloom will do harm to water environment, so this paper studies the growth law of Microcystis aeruginosa. Single factor experiment and orthogonal experiment were carried out by changing the influencing factors such as photoperiod, initial dosage and initial pH. The results showed that within a certain range, the larger the photoperiod, the larger the initial dosage, the higher the initial pH, the better the growth of Microcystis aeruginosa and the greater the increase of pH value. This study is to deepen the understanding of the growth law of Microcystis aeruginosa. It provides a scientific basis for controlling the growth of Microcystis aeruginosa. [ABSTRACT FROM AUTHOR]

Rhodobacter sphaeroides was used for bioremediation of wastewater polluted with cadmium (Cd) and zinc (Zn). The tolerance of the microorganism to selected heavy metals (HMs), as well as the effects of pH, temperature and inoculum size on the removal rate, was investigated. The remediation effects of R. sphaeroides were analysed at different initial concentrations of HMs. Bioremediation mechanisms were thoroughly discussed based on the results from the cell characterisation analysis. Cd and Zn could inhibit the growth of R. sphaeroides. However, Cd was more toxic than Zn, with corresponding EC50 values of 5.34 and 69.79 mg L-1. Temperature and pH had greater influence on the removal rate of HMs than inoculum size. The optimal conditions for temperature and pH were 35 °C-40 °C and pH 7, respectively. Initial concentration of HMs and remediation time also affected the removal rate. Rhodobacter sphaeroides had a relatively higher remediation effect under the present experimental conditions. The removal rates for Cd and Zn reached 97.92% and 97.76%, respectively. Results showed that biosorption and HM precipitation were the main bioremediation mechanisms. This information is necessary to better understand the removal mechanism of R. sphaeroides, and is significant for its pilot test and future practical application. [ABSTRACT FROM AUTHOR]

Recently, corrosion-resistant 1561 aluminium alloy has been widely applied to the production of curved parts. However, the sheets of this material will generate a high amount of springback during multi-point forming, which means that a large amount of springback compensation is required. In this paper, four multi-step forming paths are designed to study the effect of forming paths on the multi-point forming results of double curved parts for 1561 aluminium alloy. Numerical simulation of the multi-step forming of curved sheets is carried out by ABAQUS finite element simulation software. The simulation results indicate that the 1561 aluminium alloy double curved parts produce poor situations such as wrinkling and low forming accuracy in single-step forming, while the accuracy improves significantly and the forming quality increases after four-step forming. Therefore, a four-step forming path was adopted for stamping tests on double curved parts. The results of the accuracy inspection of the formed parts by Gom-inspect demonstrate that the quality of the curved parts can be effectively improved by four-step forming, which has a certain significance in guiding the forming preparation of parts for engineering applications. [ABSTRACT FROM AUTHOR]

In this study, the content characteristics, comprehensive pollution assessment, and morphological distribution characteristics of heavy metals (Mn, Cd, Cr, Pb, Ni, Zn, and Cu) were researched based on the processes of field investigation, sample collection, and experimental analysis. Results showed that the mean concentrations of Mn, Pb, Cr, Cu, Cd, Zn, and Ni in surface soils were 522.77, 22.56, 55.10, 25.41, 0.25, 57.02, and 48.47 mg kg¡1, respectively. The surface soil from Sunan mining area was contaminated by Cu, Cd, and Ni in different degrees, and high CV values of Cd, Zn, Pb, and Ni were influenced by local human activities possibly. The evaluation results suggested that the mean Igeo values were in the sequence of Cd (0.657) > Ni (0.052) > Cu (¡0.293) > Mn (¡0.626) > Zn (¡0.761) > Cr (¡0.884) > Pb (¡0.899). Besides, Cd was the most significant potential risk factor among all elements. Nevertheless, the Cd of bioavailable speciations with higher proportion had stronger migration and toxicity, and was more easier to be absorbed and enriched than other elements by some crops (e.g., vegetables, rice), and being at a relatively higher potential ecological risk in soil. [ABSTRACT FROM AUTHOR]

The aim of the current study was to investigate the impacts and possible mechanisms of total flavonoids of Ajuga (TFA) on glomerular mesangial cells (GMC) through in vitro observations of the impacts of TFA‑containing serum on GMC proliferation and extracellular matrix (ECM) secretion in lipopolysaccharides (LPS)‑induced rats. Rat GMC was cultured in vitro, using LPS to stimulate the proliferation of GMC and the secretion of ECM; meanwhile, TFA‑containing serum (TFA‑S) was used for the intervention. Methyl thiazolyl tetrazolium (MTT) assay was performed to test the proliferation of GMC; enzyme‑linked immunosorbent assay (ELISA) was used to detect the expressions of fibronectin (FN) and collagen IV (Col‑IV) in cell supernatant, flow cytometry was performed to detect the cell cycle, and reverse transcription‑polymerase chain reaction was performed to detect the expression levels of matrix metalloproteinase 9 (MMP‑9) mRNA and transforming growth factor β1 (TGF‑β1) mRNA. The GMC proliferation and the expressions of FN and Col‑IV in cell supernatant were significantly reduced after 24 and 48 h TFA‑S intervention (P<0.05 or 0.01). A total of 48 h subsequent to the intervention, the proportion of GMC in the G1 phase and the relative expression of MMP‑9 mRNA were significantly increased (P<0.05 or 0.01), however the proportion of GMC in S phase and the relative expression of TGF‑β1 mRNA were significantly reduced (P<0.05 or 0.01). TFA‑S can inhibit LPS‑induced GMC proliferation and ECM accumulation, and its roles are associated with regulating the cell cycle and the expression levels of TGF‑β1 and MMP‑9. [ABSTRACT FROM AUTHOR]