Sensitivity of Marine Controllable Source Electromagnetic Soundings for Identifying Plume Migration in Offshore CO_(2) Storage

Offshore carbon dioxide(CO_(2)) storage is an effective method for reducing greenhouse gas emissions. However, when using traditional seismic wave methods to monitor the migration of sequestration CO_(2) plumes, the characteristics of wave velocity changes tend to become insignificant beyond a certain limit. In contrast, the controllable source electromagnetic method(CSEM) remains highly sensitive to resistivity changes. By simulating different CO_(2) plume migration conditions, we established the relevant models and calculated the corresponding electric field response characteristic curves, allowing us to analyze the CSEM's ability to monitor CO_(2) plumes. We considered potential scenarios for the migration and diffusion of offshore CO_(2) storage, including various burial depths, vertical extension diffusion, lateral extension diffusion,multiple combinations of lateral intervals, and electric field components. We also obtained differences in resistivity inversion imaging obtained by CSEM to evaluate its feasibility in monitoring and to analyze all the electric field(Ex, Ey, and Ez) response characteristics. CSEM has great potential in monitoring CO_(2) plume migration in offshore saltwater reservoirs due to its high sensitivity and accuracy. Furthermore, changes in electromagnetic field response reflect the transport status of CO_(2) plumes, providing an important basis for monitoring and evaluating CO_(2)transport behavior during storage processes.

Tetrabromobisphenol A and hexabromocyclododecane in sediments from the Zhujiang(Pearl) River Estuary and South China Sea

Marine sediments collected from the Zhujiang(Pearl) River Estuary(ZRE) and South China Sea(SCS) were utilized to study the occurrence and spatial distribution of tetrabromobisphenol A(TBBPA) and hexabromocyclododecane(HBCDD).The levels of TBBPA and HBCDD in sediments ranged from not detected(nd) to 6.14 ng/g dry weight(dw) and nd to 0.42 ng/g dw.TBBPA concentrations in marine sediments were substantially higher than HBCDD.The concentrations of TBBPA and HBCDD in the ZRE sediments were significantly greater than those in the SCS.α-HBCDD(48.7%) and γ-HBCDD(46.2%) were the two main diastereoisomers of HBCDD in sediments from the ZRE,with minor contribution of β-HBCDD(5.1%).HBCDD were only found in one sample from the northern SCS.The enantiomeric fraction of α-HBCDD in sediments from the ZRE was obviously greater than 0.5,indicating an accumulation of(+)-α-HBCDD.The enantiomers of HBCDD were not measured in sediments from the SCS.This work highlighted the environmental behaviors of TBBPA and HBCDD in marine sediments.

Preserved egg white alleviates DSS-induced colitis in mice through the reduction of oxidative stress,modulation of inflammatory cytokines,NF-κB,MAPK and gut microbiota composition

Traditional Chinese preserved egg products have exhibited some anti-inflammatory effects,but their mechanisms of action remain unknown.This study aimed to investigate the anti-inflammatory effects of preserved egg white(PEW)treatment on dextran sulfate sodium(DSS)-induced colitis in mice and the underlying mechanisms.The results showed that treatment with PEW in mice with DSS-induced colitis for 14 days effectively improved the clinical signs,inhibited the secretion and gene expression of pro-inflammatory cytokines,and reduced myeloperoxidase(MPO)activity and oxidative stress levels.In addition,western blotting results showed that PEW significantly suppressed DSS-induced phosphorylation levels of nuclear factor-kappa B(NF-κB)p65 and p38 mitogen-activated protein kinase(MAPK)in colon tissues of mice with colitis.PEW also enhanced the production of short-chain fatty acids(SCFAs)and modulated gut microbiota composition in mice with DSS-induced colitis,including increasing the relative abundance of beneficial bacteria Lachnospiraceae,Ruminococcaceae and Muribaculaceae,and reducing the relative abundance of harmful bacteria Proteobacteria.Taken together,our study demonstrated that preserved egg white could alleviate DSS-induced colitis in mice through the reduction of oxidative stress,modulation of inflammatory cytokines,NF-κB,MAPK and gut microbiota composition.

Spatial distribution and inventory of natural gas hydrate in the Qiongdongnan Basin,northern South China Sea

Natural gas hydrate is a potential clean energy source and is related to submarine geohazard,climate change,and global carbon cycle.Multidisciplinary investigations have revealed the occurrence of hydrate in the Qiongdongnan Basin,northern South China Sea.However,the spatial distribution,controlling factors,and favorable areas are not well defined.Here we use the available high-resolution seismic lines,well logging,and heat flow data to explore the issues by calculating the thickness of gas hydrate stability zone(GHSZ)and estimating the inventory.Results show that the GHSZ thickness ranges between mostly~200 and 400 m at water depths>500 m.The gas hydrate inventory is~6.5×109-t carbon over an area of~6×104 km2.Three areas including the lower uplift to the south of the Lingshui sub-basin,the Songnan and Baodao sub-basins,and the Changchang sub-basin have a thick GHSZ of~250-310 m,250-330 m,and 350-400 m,respectively,where water depths are~1000-1600 m,1000-2000 m,and2400-3000 m,respectively.In these deep waters,bottom water temperatures vary slightly from~4 to 2℃.However,heat flow increases significantly with water depth and reaches the highest value of~80-100 mW/m2 in the deepest water area of Changchang sub-basin.High heat flow tends to reduce GHSZ thickness,but the thickest GHSZ still occurs in the Changchang sub-basin,highlighting the role of water depth in controlling GHSZ.The lower uplift to the south of the Lingshui sub-basin has high deposition rate(~270-830 m/Ma in 1.8-0 Ma);the thick Cenozoic sediment,rich biogenic and thermogenic gas supplies,and excellent transport systems(faults,diapirs,and gas chimneys)enables it a promising area of hydrate accumulation,from which hydrate-related bottom simulating reflectors,gas chimneys,and active cold seeps were widely revealed.

Low-noise,low-power-consumption seafloor vector magnetometer

The seafloor vector magnetometer is an effective tool for marine geomagnetic surveys and seafloor magnetotelluric(MT)detection.However,the noise,power consumption,cost,and volume characteristics of existing seafloor vector magnetometers are insufficient for practical use.Therefore,a low-noise,low-power-consumption seafloor vector magnetometer that can be used for data acquisition of deep-ocean geomagnetic vector components is developed and presented.A seafloor vector magnetometer mainly consists of a fluxgate sensor,data acquisition module,acoustic release module,glass sphere,frame,burn-wire release,and anchor.A new low-noise data acquisition module and a fluxgate sensor greatly reduce power consumption.Furthermore,compact size is achieved by integrating an acoustic telemetry module and replacing the acoustic release with an external burn-wire release.The new design and magnetometer characteristics reduce the volume of the instrument and the cost of hardware considerably,thereby improving the integrity and deployment efficiency of the equipment.Theoretically,it can operate for 90 days underwater at a maximum depth of 6000 m.The seafloor vector magnetometer was tested in the South China Sea and the Philippine Sea and obtained high-quality geomagnetic data.The deep-water environment facilitates magnetic field data measurements,and the magnetometer has an approximate noise level of 10 pT/rt(Hz)@1 Hz,a peak-to-peak value error of 0.2 nT,and approximate power consumption of 200 mW.The fluxgate sensor can measure the magnetic field in the lower frequency band and realize geomagnetic field measurements over prolonged periods.

Comparison of Abbott and Da-an real-time PCR for quantitating serum HBV DNA

AIM: To compare the performance of the Da-an real-time hepatitis B virus (HBV) DNA assay and Abbott RealTime HBV assay.

Cycling hydrogen desorption properties and microstructures of MgH_(2)-AlH_(3)-NbF_(5) hydrogen storage materials

Magnesium hydride(MgH_(2)) is a candidate material for hydrogen storage.MgH_(2)-AlH_(3) composite shows superior hydrogen desorption properties than pure MgH_(2).However,this composite still suffers from poor cycling performance.In this work,NbF_(5) was utilized to improve the cycling properties of the MgH_(2)-AlH_(3) composite.Cycling hydrogen desorption studies show that NbF_(5) significantly improves the cycling stability of MgH_(2)-AlH_(3).The MgH_(2)-AlH_(3)-NbF_(5) composite can release about 2.7 wt% of hydrogen at 300℃ for 1 h and the hydrogen desorption capacity can maintain at 2.7 wt% for more than100 cycles.In comparison,the hydrogen desorption capacity of the MgH_(2)-AlH_(3) composite is decreasing with the cycle number increasing.The capacity is reduced from a maximum value of 3.3 wt% to about 1.0 wt% after 40 cycles.Brunauer-Emmett-Teller(BET) surface area measurements show that the particle size of MgH_(2)-AlH_(3) composite decreases after cycling,which means pulverization of the composite.NbF_(5) can to some extent suppress the pulverization of the composite during cycling,which partially contributes to the improvement of the cycling hydrogen desorption properties of the material.