Impact of seepage flow on sediment resuspension by internal solitary waves:parameterization and mechanism

Sediment incipient motion is the first step in sediment resuspension.Previous studies ignored the effect of seepage flow on the mobility of sediment particles and simplified the seabed surface as a rigid boundary.A flume experiment was designed to innovatively divide the seabed into two parts to control the dynamic response of the seabed and control the seepage conditions.In the experiment,the seabed sediments and the amplitude of internal solitary waves(ISWs)were changed to compare and analyze the impact of seepage flow on the sediment resuspension by shoaling ISWs.Moreover,parametric research and verification were carried out.Results indicate that seepage flow can greatly influence fine sand,promote sediment resuspension,and increase the amount of suspension by two times on average.However,seepage flow had a little effect on the suspension of clayey silt and sandy silt.Besides,seepage force was added to the traditional gravity,drag force,and uplift force,and the parameterization of threshold starting shear stress of coarse-grained sediments was developed.The results of this parameterization were verified,and seepage force was critical to parameterization.The threshold starting shear stress was reduced by 54.6%after increasing the seepage force.The physical mechanism of this process corresponded to the vertical reciprocating transient seepage in and out the seabed interface caused by the wave-induced transient excess pore water pressure.This quantitative study on seepage flow for shear stress of coarse-grained sediments induced by ISWs is critical to geohazard assessment.

Mutation analyses of integrated HBV genome in hepatitis B patients

Little has been learnt in the last 30 years about detection of HBV genome as well as its mutation analysis between hepatitis B fathers （HBF） and their children. In this study, we used nest polymerase chain reaction （PCR）, fluorescence in situ hybridization （FISH）, and DNA sequencing analysis, to examine the integrated HBV genome in paraffin-embedded testis tissues, which were taken as samples from HBE and in peripheral blood mononuclear cells （PBMC） from 74 cases of HBFs and their children who were born after their fathers＇ HBV infection （caHBF）. We found that HBV DNA existed in testis tissues, mainly in the basilar parts of the seminiferous tubules, and also in PBMC of HBE It was also documented that there were point mutations of poly-loci, insertions and deletions of nucleotides in integrated HBV genomes, and the types of gene mutations in the HBFs were similar to those in caHBE This study addresses the major types of gene mutations in integrated HBV genome in human patients and also presents reliable evidence of possible genetic transmission of hepatitis B.