[Derivation of the Thresholds of Available Concentrations of Heavy Metals in Soil Based on Agricultural Product Safety].

Based on the total and available concentrations of heavy metal elements in agricultural soil, and the concentrations of heavy metals in rice collected from Daye city, Hubei province, and the thresholds of available concentrations of heavy metals were derived by species sensitivity distribution (SSD). The over-standard rates of Cd and Cu in the soil were 90.7% and 42.6%, respectively, which indicates that agricultural soil in Daye city exhibits signs of Cd and Cu pollution. The rates of Cd and Pb were 50.9% and 89.8% in brown rice samples, respectively, which exceeds the safety standards of agricultural products. The SSD curves for Cd and Pb were fitted with BurrⅢ distribution based on the ratio of the concentration in brown rice and the available concentration in the soil. The hazardous concentrations (HC5) were derived inversely from the agriculture product safety standards. The thresholds of available Cd and Pb were 0.02 mg·kg-1 and 0.005 mg·kg-1, respectively. Compared with those of available Cd in other countries and studies, the threshold of available Cd is scientifically shown to be reasonable. Soil is not necessarily the main source of Pb in rice; thus, the rice species does not represent the derivation of the threshold of available Pb. Moreover, a lack of the accumulation data of Pb at low accumulation levels and multiple soil pollution levels leads to unreliable derivation. The results indicate that the threshold of available Pb does not have practical significance in soil pollution control.

DDT, DDD, and DDE in soil of Xiangfen County, China: Residues, sources, spatial distribution, and health risks.

We collected and analyzed 128 surface soil samples from Xiangfen County for dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloroethane (DDD), and dichlorodiphenyldichloroethylene (DDE). Total DDT concentrations (DDTs; sum of p,p'-DDD, p,p'-DDE, and p,p'-DDT) ranged from ND to 427.81 ng g(-1) (dry weight, dw), with a mean of 40.26 ng g(-1) (dw). Among the three compounds, p,p'-DDD was the most dominant. The DDTs in Xiangfen County soils mainly originated from historical DDT use, but there were also new inputs likely related to dicofol use. The DDTs in Xiangfen County soils were mainly degraded under anaerobic conditions, and direct degradation to DDD was the main degradation route. Regions with relatively high concentrations of DDTs were mainly located in North and South Xiangfen County. In these regions, many soil samples contained p,p'-DDT as the predominant pollutant, suggestive of extensive new inputs of DDT. A health risk assessment revealed that there are no serious long-term health impacts of exposure to DDTs in soil, for adults or children.

The high expression level of programmed death-1 ligand 2 in oral lichen planus and the possible costimulatory effect on human T cells.

BACKGROUND: Oral lichen planus (OLP) is a T-cell-mediated chronic autoimmune disease whose precise etiology is unknown. The recently identified costimulatory programmed death-1 (PD-1) molecule and its ligands, PD-L1 and PD-L2, have been identified as CD28-B7 family molecules and constitute a regulatory pathway of potential therapeutic use in immune-mediated diseases. METHODS: We examined the expression of two ligands of PD-1 at both the protein and gene level in the focal mucosa and peripheral blood of OLP patients using immunohistochemistry and real-time PCR. Next, we used the PD-L2.Ig fusion protein and observed its effects on T cells, which were co-cultured with IFN-γ-treated keratinocytes (KCs) in the presence of PHA. RESULTS: We found that the expression of PD-L2 at both the gene and protein level was statistically different in peripheral blood and local lesion tissue of patients with OLP compared to the normal controls. The proliferation ability of T cells and the expression level of IFN-γ in the supernatant of the above co-culture model were significantly augmented (P < 0.05). PD-L2.Ig fusion protein significantly aggravated the apoptosis of T cells, inhibited the proliferation of T cells and decreased the release levels of IL-2 and IFN-γ in the model (P < 0.05). CONCLUSION: These data show that the increased expression of PD-L2, as a costimulatory molecule, may have an important modulatory function on the local immune responses of OLP in vivo.

[Study on the expression and potential effect of PD-L1mRNA and PD-L2mRNA in oral lichen planus].

PURPOSE: To study the expression of PD-L1 and PD-L2mRNA in oral lichen planus(OLP) patients' peripheral blood and focal mucosa, and the different expression of target molecules in gene level in different clinical and pathological OLP groups. METHODS: The expression of PD-L1 and PD-L2 mRNA in OLP patients, which included 35 reticular and 25 atrophic-erosive OLP patients, 38 cases without dysplasia and 22 cases with dysplasia, was examined by real-time PCR. Peripheral blood and mucosa from 10 volunteers were used as control. All the results were analysed with Wilcoxon test by SAS.6.12 software package. RESULTS: The expression of PD-L2mRAN, but not PD-L1, was significantly higher in oral mucosa of OLP patients (P<0.01), while decreased in OLP patients' peripheral blood (P=0.0415). The gene expression of PD-L2 differed between different clinical types, and had highly significant correlation between the OLP patients' focal mucosa and peripheral blood(r=0.6976, P<0.0001). CONCLUSIONS: PD-L2 may have some potential effect on the pathogenesis of OLP at systemic and local level.

[Air stripping-UASB process for the treatment of evaporator condensate from a Kraft pulp mill].

Evaporator condensate from a kraft pulp mill is characterized by high temperature, high strength, poor nutrition, and some odor and inhibitive materials. In this study, air stripping-UASB process was developed to treat the wastewater from a kraft pulp mill. The lab scale study demonstrated that air stripping process removed 70%-80% of the volatile organic sulfur compounds. After that, the UASB reactor showed high efficiency, at the organic loading rate (COD) of 30 kg x (m3 x d)(-1), COD removal was retained about 95%. On the other hand, the inoculated granules were broken in the new surroundings and were replaced with the newly formed granules The scanning electronic microscope (SEM) observation showed wide difference of the predominant anaerobic microorganisms in the seed and newly formed granules.