Distribution and risk assessment of heavy metals in surface sediments of coastal mudflats on Leizhou Peninsula,China

Mudflats play a vital role in maintaining the dynamic balance between sea and land.To understand the characteristics,sources,and pollution risks of six heavy metals(As,Cd,Cr,Cu,Hg,and Pb)in the coastal mudflats on the Leizhou Peninsula,257 surface sediment samples were studied using mathematical statistics,correlation analysis,and factor analysis.The results show that the overall concentrations of these heavy metals are low although there are several high abnormal points in the local areas.The strong correlation between these heavy metals indicates that the sources of some of the metals are similar,yet their elemental combinations in different cities(counties)varied.According to the calculated enrichment factor(EF),anthropogenic activity-induced heavy metals were determined in order of decreasing influence:As,Cd,Pb,Cr,Cu,and Hg.The low EF values of Hg indicate that it does not present as a contaminant in the study area,while low values of Cr and Cu from the Lianjiang City suggest that these two metals were also attributed to natural sources.The presence of As,Cd,Cr,Cu,and Pb from the remaining cities(counties)should be influenced by anthropogenic activities.The overall potential ecological risk index indicates that the ecological risks posed by the six analyzed heavy metals to the Leizhou Peninsula mudflats,in order of decreasing risk,are Cd,As,Hg,Pb,Cu,and Cr.It is noteworthy that only Cd in Lianjiang City demonstrated substantial ecological risk.Other examined heavy metals in other cities of the study area showed slight ecological risk.

0.65MPa高水压盾构机新型盾尾密封系统设计与研究

针对0.65 MPa高水压条件，优化盾构机盾尾密封系统，以适应高水压下盾构掘进施工。通过模拟盾构掘进过程和试验优化盾尾密封油脂的注入量，最终形成盾尾密封系统结构设计方案。同时根据试验得出的盾尾密封油脂的标准用量，得出油脂注入量与推进速度关系，并指导实际施工。在保证盾尾密封性能的同时，又能节约油脂注入成本。

Clinical Study of Different Immunosuppressive Regimens in Liver Transplant Patients

[Objectives]To explore the clinical effect of different immunosuppressive regimens in liver transplant patients.[Methods]The study patients were 147 liver transplant patients who underwent liver transplantation in a hospital and received CNI-based immunosuppression in the first two years after the operation.Both groups were given mycophenolate mofetil+glucocorticoid,and the control group was additional given cyclosporine,and the experimental group was given tacrolimus.Followed up and made a record of the liver and kidney function indicators,blood routine examination,blood sugar,and blood concentration of immunosuppressive drugs in the two groups of patients at 3,6,12,18,and 24 months after the operation,and the clinical pharmacist regularly adjusted the dose of immunosuppressive drugs.The renal function indicators of the two groups were compared:glomerular filtration rate(eGFR)and serum creatinine(Scr)level.[Results]Within 24 months after the operation,the eGFR level in the two groups showed a declining trend,and the Scr level showed a rising trend,indicating a decline in renal function;the renal function of the control group decreased at 3 months after operation,and the difference was significant(P<0.05);the renal function of the experimental group also decreased at 12 months after operation,and the difference was significant(P<0.05).[Conclusions]The TAC based triple immunization regimen can delay the decline of renal function in liver transplant patients,and the efficacy is significantly better than the CsA based triple immunization regimen.

The molecular determinants governing the immunogenicity of Japanese encephalitis live attenuated vaccines

In the course of isolating the attenuated Japanese encephalitis vaccine SA14-14-2,two attenuated strains SA14-9-7 and SA14-5-3 were also obtained that elicited low antibody responses in humans(o10%and 62%,respectively)and exerted much weaker immune protection in animal challenge experiments.However,the reason for these differences remains unknown.In order to understand why SA14-14-2 is superior to SA14-9-7 and SA14-5-3,we employed a reverse genetics method to identify the key mutations in the virus genome that determine the immunogenicity of live attenuated Japanese encephalitis viruses.We first sequenced the full genomic sequences of SA14-9-7 and SA14-5-3 and found mutations that changed four amino-acid base pairs when compared to the envelope gene of SA14-14-2.We mutated the genome of SA14-14-2 to generate these mutations both singly(E-177,E-264,E-279 and E-315)and in combination(E-177/264,E-279/315 and E-177/264/279/315)and tested these mutants along with parental strains SA14-14-2,SA14-9-7 and SA14-5-3 for their immunogenicity in vivo.When mice were immunized with SA14-9-7 and SA14-5-3,lower levels of neutralizing antibodies were generated compared with the immune response to SA14-14-2.Furthermore,SA14-5-3 was more immunogenic than SA14-9-7,which replicated the results previously seen in humans.Point mutations E-177,E-264,E-279 and E-315 diminished the immunogenicity of SA14-14-2 with E-264 and E-315,contributing the most to this phenotype.The mutant rJEV(E-177/E-264/E-279/E-315)containing all four point mutations exhibited the lowest immunogenicity with a seroconversion rate of 0 at an inoculation dose of 103 PFU(plaque-forming unit).We have identified the key amino acids in the envelope protein that account for the superior immunogenicity of SA14-14-2.

Compressive Behavior of Wood-based 2-D Lattice Structure under Multivariable Analysis

In order to optimize the out-of-plane compression performance of the wood structure,wood-based 2-D lattice structures were designed and manufactured with oriented strand board as the panel and birch round stick as the core by using a simple insert-glue method.In this experiment,the different thicknesses of the upper and lower panels,the different shavings arrangement directions of the upper and lower panels and the different configurations of the specimens were used to analyze the compression performance of the specimens under multivariable conditions.Through the combination of experimental test and theoretical analysis,we analyzed and compared different failure types of the structure and multiple compression parameters.The results showed that the shavings arrangement direction of the panel has a more important influence on the whole specimen than the thickness of the panel,especially the transverse shavings of the panel can withstand greater shear stress than the longitudinal shavings for a specimen.