Mercury accumulation,distribution,and isotopic composition in tissues of the Collared Scops Owl(Otus lettia)

Mercury is a ubiquitous contaminant known to accumulate in wildlife,particularly bird species at higher trophic levels.Knowledge of tissue-specific Hg distributions aids our understanding of Hg bioaccumulation in organisms.In this study,one adult and three juvenile Collared Scops Owls(Otus lettia)were studied to elucidate the bioaccumulation of Hg in body tissues.Six tissues and organs(feathers,nails,heart,liver,gizzard,and muscle),as well as gastric contents,were examined for total Hg(THg)and methylmercury(MeHg)contents,Hg isotopic compositions including mass-dependent fractionation(MDF;δ202Hg)and mass-independent fractionation(MIF;Δ199Hg andΔ201Hg),and C(δ13C)and N(δ15N)isotopic compositions.Tissue-specific THg and MeHg concentrations in the adult were in the ranges of 150–1360 ng/g and17–1060 ng/g,and lower in the juveniles at 91–419 ng/g and 67–350 ng/g,respectively.Theδ^(202)Hg values in the adult were strongly negative at-1.75‰±0.17‰compared with the juveniles at-0.99‰±0.25‰.The adult exhibited lower MIF values than the juveniles,at0.23‰±0.07‰forΔ^(199)Hg and 0.2‰±0.11‰forΔ^(201)Hg,comparedwith0.81‰±0.09‰and0.66‰±0.07‰,respectively.The lower adult MDF and MIF values suggest that the adult tended to accumulate negative Hg isotopes but the juvenile's positive Hg isotopes.Differences between adult and juvenile tissue Hg concentrations indicate that metabolic processes play an important role in Hg accumulation.

Sodium dodecyl sulfate (SDS) as an effective corrosion inhibitor for Mg-8Li-3Al alloy in aqueous NaCl: A combined experimental and theoretical investigation

The corrosion inhibition behavior of Mg-8Li-3Al alloy in NaCl solution with sodium dodecyl sulfate(SDS)was investigated by hydrogen analysis,scanning electron microscopy(SEM),electrochemical test,scanning Kelvin probe force microscopy(SKPFM)and computational methods.Results showed that the corrosion resistance of Mg-8Li-3Al alloy in NaCl solution was effectively improved with SDS.The SEM and SKPFM results confirmed a dense,200 nm-thick SDS-adsorbed layer had formed on the alloy surface.The separation energy ΔE_(gap) and adsorption energy E_(ads) of SDS on the Mg surface were calculated by density functional theory and molecular dynamics simulations,respectively.And the corrosion inhibition mechanism was hypothesized and described.

Evaluation of the potential risks of heavy metal contamination in rice paddy soils around an abandoned Hg mine area in Southwest China

To assess the potential ecological and health risks of trace elements(Hg,Cd,As,Mn,Sb,Pb,Cu,Ni,Cr,and Zn),a total of 138 soil samples from rice paddies were collected during the rice harvest season in the Wanshan mining area,Guizhou Province,Southwest China.Factors of the pollution load index(PLI),geo-accumulation index(I-Geo),enrichment factor(EF),and risk index(RI)were determined.High concentrations of Hg,Sb,As,Zn,Cd,Cu,and Mn were observed in the soils.The PLI,I-Geo,and EF results all showed high levels of contamination by Hg and Sb and moderate levels of contamination by As,Pb,Zn,Cu,Cd,and Mn.There was no significant contamination from Ni and Cr.The RI was very high,with Hg as the dominant pollutant,as expected,indicating that the historical large-scale Hg mining,as well as artisanal mining,has had a significant impact on the Wanshan area.Moreover,coal combustion,manganese factories,and the use of agrochemicals by the local population could also have an impact on the soil through the introduction of heavy metal loads.To address the current state of contamination,pollutant remediation and the regulation control of the anthropogenic activities in Wanshan are urgently needed.

PR-Set7 is Degraded in a Conditional Cul4A Transgenic Mouse Model of Lung Cancer

Background and objective Maintenance of genomic integrity is essential to ensure normal organismal development and to prevent diseases such as cancer.PR-Set7(also known as Set8)is a cell cycle regulated enzyme that catalyses monomethylation of histone 4 at Lys20(H4K20me1)to promote chromosome condensation and prevent DNA damage.Recent studies show that CRL4CDT2-mediated ubiquitylation of PR-Set7 leads to its degradation during S phase and after DNA damage.This might occur to ensure appropriate changes in chromosome structure during the cell cycle or to preserve genome integrity after DNA damage.Methods We developed a new model of lung tumor development in mice harboring a conditionally expressed allele of Cul4A.We have therefore used a mouse model to demonstrate for the first time that Cul4A is oncogenic in vivo.With this model,staining of PR-Set7 in the preneoplastic and tumor lesions in Adeno Cre-induced mouse lungs was performed.Meanwhile we identified higher protein level changes ofγ-tubulin and pericentrin by IHC.Results The level of PR-Set7 down-regulated in the preneoplastic and adenocarcinomous lesions following over-expression of Cul4A.We also identified higher levels of the proteins pericentrin andγ-tubulin in Cul4A mouse lungs induced by Adeno Cre.Conclusion PR-Set7 is a direct target of Cul4A for degradation and involved in the formation of lung tumors in the conditional Cul4A transgenic mouse model.

Influence of tungsten particle size on microstructure and mechanical properties of high strength and tough tungsten particle-reinforced nickel-based composites by laser-direct energy deposition

Tungsten(W)particle-reinforced nickel(Ni)-based composites were fabricated via laser-direct energy de-position(L-DED).The influence of the W particle size on the microstructure and mechanical properties of the deposited samples was systematically studied.The results indicate that refining the W particle size could refine theγ-Ni grains and subgrains,thin the(Ni,Cr)_(4)W interface layer,and increase the disloca-tion density of the intergranular matrix,thus improving the tensile strength and elongation of the L-DED samples.As W particle size decreased from 75 to 150μm to 6.5-12μm,the tensile strength and elonga-tion of the deposited samples increased by 150 MPa and 2.9 times to 1347.6±15.7 MPa and 17.5±0.4%,respectively.Based on the properties of the interface(Ni,Cr)_(4)W,a load-transfer efficiency factor suitable for this composite was proposed and the load-transfer strengthening formula was optimized.A quanti-tative analysis of the strengthening mechanisms was established considering load-transfer strengthening,Hall-Petch strengthening,thermal-mismatch strengthening,and solid-solution strengthening.The calcu-lated contribution of each strengthening mechanism to the yield strength and theoretical calculations were in good agreement with the experimental data.The article breaks the bottleneck of poor plasticity of W particle-reinforced Ni-based composites prepared by L-DED and provides a theoretical basis for the construction design of W particle-reinforced Ni-based composites with excellent mechanical properties.

Parallel-Data-Based Social Evolution Modeling

Abnormal or drastic changes in the natural environment may lead to unexpected events,such as tsunamis and earthquakes,which are becoming a major threat to national economy.Currently,no effective assessment approach can deduce a situation and determine the optimal response strategy when a natural disaster occurs.In this study,we propose a social evolution modeling approach and construct a deduction model for self-playing,self-learning,and self-upgrading on the basis of the idea of parallel data and reinforcement learning.The proposed approach can evaluate the impact of an event,deduce the situation,and provide optimal strategies for decisionmaking.Taking the breakage of a submarine cable caused by earthquake as an example,we find that the proposed modeling approach can obtain a higher reward compared with other existing methods.