Vertical-looking radar (VLR) has allowed long-term automatic monitoring of the altitudinal and temporal dynamics of high- flying insect populations. To investigate whether ground beetle, insect of Coleoptera, was ca...Vertical-looking radar (VLR) has allowed long-term automatic monitoring of the altitudinal and temporal dynamics of high- flying insect populations. To investigate whether ground beetle, insect of Coleoptera, was capable of migrating and its migration pattern by taking advantages of capability of the VLR for long-term real-time automatic monitoring, the migration of Coleoptera ground beetle was investigated by setting up radar observation points, making long-term observation using the VLR and related supplementary equipment, and analyzing low altitude air current and large area circulating current in combination with the meteorological data. Information obtained in 2005 and 2006 showed that the seasonal activities of ground beetles traps of trap lamps were mainly from late June to late August, peak period was mainly in August, seasonal traps of high-altitude lamps and ground lamps were featured by sudden increase and sudden decrease; in peak period, the height of radar echo point could be as high as 600 m, while it was mainly below the height of 450 m; night activities mainly occurred from 20:00 to 22:00, in very few nights, radar echo could last until about 04:00, changes in numbers of ground beetles within the searchlights were consistent with radar echo intensity; ground beetle images were successfully trapped in the sweep nets carried by captive balloons at the height of 200 m. Some species of Carabidaes had some degrees of migration, thus providing the foundation for investigating the migration of Coleoptera insects.展开更多
Molecular dynamics simulations of high temperature annealing of copper bicrystals have been carried out. The bicrystals have planar grain boundaries, and the gain size varies in nano range. An EAM (embedded atom metho...Molecular dynamics simulations of high temperature annealing of copper bicrystals have been carried out. The bicrystals have planar grain boundaries, and the gain size varies in nano range. An EAM (embedded atom method) potential of FS type is used for calculating the interatomic forces. The results show that in nanocrystalline copper, GB migration driven by inter-GB reaction can take place. A critical grain size is identified, below which the inter-GB reaction becomes strong enough to trigger GB motion, which accelerates rapidly and leads to annihilation of the grain boundaries. The critical size is found to be 16 atomic radii. A "through intermediate grain mechanism" is identified for the nano-grain boundary motion observed, which is never reported for GB migrations of conventional polycrystalline metals.展开更多
Ocean-Bottom Node(OBN)acquisitions provide both non-converted and converted reflection energy.There is a clear advantage to independently imaging both P-and S-waves,as they provide more information collectively than e...Ocean-Bottom Node(OBN)acquisitions provide both non-converted and converted reflection energy.There is a clear advantage to independently imaging both P-and S-waves,as they provide more information collectively than either does alone.In many conventional converted-wave pre-stack migration algorithms,density is treated as a constant,which is not the real-life case on earth.S-wave velocity and density information is crucial for hydrocarbon detection because it helps in the identification of porefilling fluids.In this paper,we focused on the effect of density on imaging,and developed a method of reverse-time migration(RTM)on converted s-waves of varying densities(VD-RTMCS).Phase correction was required prior to pre-stack migration to avoid constructive interference between data from adjacent sources.Synthetic data examples showed that when density variations were included,image profiles showed advantages in signal-to-noise ratio,vertical resolution and imaging of complex structures.展开更多
Schwann cell transplantation is considered one of the most promising cell-based therapy to repair injured spinal cord due to its unique growth-promoting and myelin-forming properties.A the Food and Drug Administration...Schwann cell transplantation is considered one of the most promising cell-based therapy to repair injured spinal cord due to its unique growth-promoting and myelin-forming properties.A the Food and Drug Administration-approved Phase I clinical trial has been conducted to evaluate the safety of transplanted human autologous Schwann cells to treat patients with spinal cord injury.A major challenge for Schwann cell transplantation is that grafted Schwann cells are confined within the lesion cavity,and they do not migrate into the host environment due to the inhibitory barrier formed by injury-induced glial scar,thus limiting axonal reentry into the host spinal cord.Here we introduce a combinatorial strategy by suppressing the inhibitory extracellular environment with injection of lentivirus-mediated transfection of chondroitinase ABC gene at the rostral and caudal borders of the lesion site and simultaneously leveraging the repair capacity of transplanted Schwann cells in adult rats following a mid-thoracic contusive spinal cord injury.We report that when the glial scar was degraded by chondroitinase ABC at the rostral and caudal lesion borders,Schwann cells migrated for considerable distances in both rostral and caudal directions.Such Schwann cell migration led to enhanced axonal regrowth,including the serotonergic and dopaminergic axons originating from supraspinal regions,and promoted recovery of locomotor and urinary bladder functions.Importantly,the Schwann cell survival and axonal regrowth persisted up to 6 months after the injury,even when treatment was delayed for 3 months to mimic chronic spinal cord injury.These findings collectively show promising evidence for a combinatorial strategy with chondroitinase ABC and Schwann cells in promoting remodeling and recovery of function following spinal cord injury.展开更多
Rechargeable magnesium batteries(RMBs)have been considered a promising“post lithium-ion battery”system to meet the rapidly increasing demand of the emerging electric vehicle and grid energy storage market.However,th...Rechargeable magnesium batteries(RMBs)have been considered a promising“post lithium-ion battery”system to meet the rapidly increasing demand of the emerging electric vehicle and grid energy storage market.However,the sluggish diffusion kinetics of bivalent Mg^(2+)in the host material,related to the strong Coulomb effect between Mg^(2+)and host anion lattices,hinders their further development toward practical applications.Defect engineering,regarded as an effective strategy to break through the slow migration puzzle,has been validated in various cathode materials for RMBs.In this review,we first thoroughly understand the intrinsic mechanism of Mg^(2+)diffusion in cathode materials,from which the key factors affecting ion diffusion are further presented.Then,the positive effects of purposely introduced defects,including vacancy and doping,and the corresponding strategies for introducing various defects are discussed.The applications of defect engineering in cathode materials for RMBs with advanced electrochemical properties are also summarized.Finally,the existing challenges and future perspectives of defect engineering in cathode materials for the overall high-performance RMBs are described.展开更多
The presence of endogenous neural stem/progenitor cells in the adult mammalian brain suggests that the central nervous system can be repaired and regenerated after injury.However,whether it is possible to stimulate ne...The presence of endogenous neural stem/progenitor cells in the adult mammalian brain suggests that the central nervous system can be repaired and regenerated after injury.However,whether it is possible to stimulate neurogenesis and reconstruct cortical layers II to VI in non-neurogenic regions,such as the cortex,remains unknown.In this study,we implanted a hyaluronic acid collagen gel loaded with basic fibroblast growth factor into the motor cortex immediately following traumatic injury.Our findings reveal that this gel effectively stimulated the proliferation and migration of endogenous neural stem/progenitor cells,as well as their differentiation into mature and functionally integrated neurons.Importantly,these new neurons reconstructed the architecture of cortical layers II to VI,integrated into the existing neural circuitry,and ultimately led to improved brain function.These findings offer novel insight into potential clinical treatments for traumatic cerebral cortex injuries.展开更多
Since China’s reform and opening-up,the growing disparity between urban and rural areas and regions has led to massive migration.With China’s Rural Revitalization Strategy and the industrial transfer from the easter...Since China’s reform and opening-up,the growing disparity between urban and rural areas and regions has led to massive migration.With China’s Rural Revitalization Strategy and the industrial transfer from the eastern coastal areas to the inland,the migration direction and pattern of the floating population have undergone certain changes.Using the 2017 China Migrants Dynamic Survey(CMDS),excluding Hong Kong,Macao,and Taiwan regions of China,organized by China’s National Health Commission,the relationship matrix of the floating population is constructed according to the inflow place of the interviewees and their outflow place(the location of the registered residence)in the questionnaire survey.We then apply the complex network model to analyze the migration direction and network pattern of China’s floating population from the city scale.The migration network shows an obvious hierarchical agglomeration.The first-,second-,third-and fourth-tier distribution cities are municipalities directly under the central government,provincial capital cities,major cities in the central and western regions and ordinary cities in all provinces,respectively.The migration trend is from the central and western regions to the eastern coastal areas.The migration network has‘small world’characteristics,forming nine communities.It shows that most node cities in the same community are closely linked and geographically close,indicating that the migration network of floating population is still affected by geographical proximity.Narrowing the urban-rural and regional differences will promote the rational distribution this population.It is necessary to strengthen the reform of the registered residence system,so that the floating population can enjoy urban public services comparable to other populations,and allow migrants to live and work in peace.展开更多
Collective cell migration is a coordinated movement of multi-cell systems essential for various processes throughout life.The collective motions often occur under spatial restrictions,hallmarked by the collective rota...Collective cell migration is a coordinated movement of multi-cell systems essential for various processes throughout life.The collective motions often occur under spatial restrictions,hallmarked by the collective rotation of epithelial cells confined in circular substrates.Here,we aim to explore how geometric shapes of confinement regulate this collective cell movement.We develop quantitative methods for cell velocity orientation analysis,and find that boundary cells exhibit stronger tangential ordering migration than inner cells in circular pattern.Furthermore,decreased tangential ordering movement capability of collective cells in triangular and square patterns are observed,due to the disturbance of cell motion at unsmooth corners of these patterns.On the other hand,the collective cell rotation is slightly affected by a convex defect of the circular pattern,while almost hindered with a concave defect,also resulting from different smoothness features of their boundaries.Numerical simulations employing cell Potts model well reproduce and extend experimental observations.Together,our results highlight the importance of boundary smoothness in the regulation of collective cell tangential ordering migration.展开更多
The potential association between colorectal cancer(CRC)and environmental pollutants is worrisome.Previous studies have found that some perfluoroalkyl acids,including perfluorooctane sulfonate(PFOS),induced colorectal...The potential association between colorectal cancer(CRC)and environmental pollutants is worrisome.Previous studies have found that some perfluoroalkyl acids,including perfluorooctane sulfonate(PFOS),induced colorectal tumors in experimental animals and promoted the migration of and invasion by CRC cells in vitro,but the underlying mechanism is unclear.Here,we investigated the effects of PFOS on the proliferation and migration of CRC cells and the potentialmechanisms involving activating the PI3K/Akt-NF-κB signal pathway and epithelial-mesenchymal transition(EMT).It was found that PFOS promoted the growth andmigration of HCT116 cells at non-cytotoxic concentrations and increased the mRNA expression of the migration-related angiogenic cytokines vascular endothelial growth factor(VEGF)and interleukin-8(IL-8).In a mechanistic investigation,the up-stream signal pathway PI3K/Akt-NF-κB was activated by PFOS,and the process was suppressed by LY294002(PI3K/Akt inhibitor)and BAY11-7082(NF-κB inhibitor)respectively,leading to less proliferation of HCT116 cells.Furthermore,matrix metalloproteinases(MMP)and EMT-related markers were up-regulated after PFOS exposure,and were also suppressed respectively by LY294002 and BAY11-7082.Moreover,the up-regulation of EMT markers was suppressed by a MMP inhibitor GM6001.Taken together,our results indicated that PFOS promotes colorectal cancer cell migration and proliferation by activating the PI3K/Akt-NF-κB signal pathway and epithelial-mesenchymal transition.This could be a potential toxicological mechanism of PFOS-induced malignant development of colorectal cancer.展开更多
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 c...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.展开更多
Colorectal cancer(CRC)stands among the top prevalent cancers worldwide and holds a prominent position as a major contributor to cancer-related mortality globally.Absent in melanoma 2(AIM2),a constituent of the interfe...Colorectal cancer(CRC)stands among the top prevalent cancers worldwide and holds a prominent position as a major contributor to cancer-related mortality globally.Absent in melanoma 2(AIM2),a constituent of the interferoninducible hematopoietic interferon-inducible nuclear antigens with 200 amino acid repeats protein family,contributes to both cancer progression and inflammasome activation.Despite this understanding,the precise biological functions and molecular mechanisms governed by AIM2 in CRC remain elusive.Consequently,this study endeavors to assess AIM2’s expression levels,explore its potential antitumor effects,elucidate associated cancer-related processes,and decipher the underlying signaling pathways in CRC.Our findings showed a reduced AIM2 expression in most CRC cell lines.Elevation of AIM2 levels suppressed CRC cell proliferation and migration,altered cell cycle by inhibiting G1/S transition,and induced cell apoptosis.Further research uncovered the participation of P38 mitogen-activated protein kinase(P38MAPK)in AIM2-mediated modulation of CRC cell apoptosis and proliferation.Altogether,our achievements distinctly underscored AIM2’s antitumor role in CRC.AIM2 overexpression inhibited proliferation and migration and induced apoptosis of CRC cells via activating P38MAPK signaling pathway,indicating AIM2 as a prospective and novel therapeutic target for CRC.展开更多
The geological storage of carbon dioxide(CO_(2)) is a crucial technology for mitigating climate change. Offshore deep saline aquifers have elicited increased attention due to their remarkable potential for storing CO_...The geological storage of carbon dioxide(CO_(2)) is a crucial technology for mitigating climate change. Offshore deep saline aquifers have elicited increased attention due to their remarkable potential for storing CO_(2). During long-term storage, CO_(2) migration in a deep saline aquifer needs special attention to prevent it from reaching risk points and leading to security issues. In this paper, a mechanism model is established according to the geological characteristics of saline aquifers in an offshore sedimentary basin in China. The CO_(2) migration over 100 years is simulated considering geological changes such as permeability, dip angle, thickness, and salinity. The effects of injection conditions on the CO_(2) migration range are also investigated. Results reveal that the migration range of CO_(2) in the injection period exceeds 70%, even if the postinjection period's duration is five times longer than that of the injection period. As the values of the above geological parameters increase, the migration range of CO_(2) increases, and permeability has a particularly substantial influence. Moreover, the influences of injection rate and well type are considerable. At high injection rates, CO_(2) has a greater likelihood of displacing brine in a piston-like scheme. CO_(2) injected by long horizontal wells migrates farther compared with that injected by vertical wells. In general, the plane migration range is within 3 000 m, although variations in the reservoir and injection parameters of the studied offshore saline aquifers are considered. This paper can offer references for the site selection and injection well deployment of CO_(2) saline aquifer storage. According to the studied offshore aquifers, a distance of at least 3 000 m from potential leakage points, such as spill points, active faults, and old abandoned wells, must be maintained.展开更多
Increasing data indicate that cancer cell migration is regulated by extracellular matrixes and their surrounding biochemical microenvironment,playing a crucial role in pathological processes such as tumor invasion and...Increasing data indicate that cancer cell migration is regulated by extracellular matrixes and their surrounding biochemical microenvironment,playing a crucial role in pathological processes such as tumor invasion and metastasis.However,conventional two-dimensional cell culture and animal models have limitations in studying the influence of tumor microenvironment on cancer cell migration.Fortunately,the further development of microfluidic technology has provided solutions for the study of such questions.We utilize microfluidic chip to build a random collagen fiber microenvironment(RFM)model and an oriented collagen fiber microenvironment(OFM)model that resemble early stage and late stage breast cancer microenvironments,respectively.By combining cell culture,biochemical concentration gradient construction,and microscopic imaging techniques,we investigate the impact of different collagen fiber biochemical microenvironments on the migration of breast cancer MDA-MB-231-RFP cells.The results show that MDA-MB-231-RFP cells migrate further in the OFM model compared to the RFM model,with significant differences observed.Furthermore,we establish concentration gradients of the anticancer drug paclitaxel in both the RFM and OFM models and find that paclitaxel significantly inhibits the migration of MDA-MB-231-RFP cells in the RFM model,with stronger inhibition on the high concentration side compared to the low concentration side.However,the inhibitory effect of paclitaxel on the migration of MDA-MB-231-RFP cells in the OFM model is weak.These findings suggest that the oriented collagen fiber microenvironment resembling the late-stage tumor microenvironment is more favorable for cancer cell migration and that the effectiveness of anticancer drugs is diminished.The RFM and OFM models constructed in this study not only provide a platform for studying the mechanism of cancer development,but also serve as a tool for the initial measurement of drug screening.展开更多
Background:Colorectal cancer is a major global health concern,exacerbated by tumor necrosis factor-alpha(TNF-α)and its role in inflammation,with the effects of Mitotic Arrest Deficient 2 Like 2(MAD2L2)in this context...Background:Colorectal cancer is a major global health concern,exacerbated by tumor necrosis factor-alpha(TNF-α)and its role in inflammation,with the effects of Mitotic Arrest Deficient 2 Like 2(MAD2L2)in this context still unclear.Methods:The colorectal carcinoma cell lines HCT116 and SW620 were exposed to TNF-αfor a period of 24 h to instigate an inflammatory response.Subsequent assessments were conducted to measure the expression of inflammatory cytokines,the activity within the p38 mitogen-activated protein kinase(p38 MAPK)and Phosphoinositide 3-Kinase/AKT Serine/Threonine Kinase pathway(PI3K/AKT)signaling cascades.Transcriptome sequencing and subsequent integrative analysis with the Cancer Genome Atlas(TCGA)program database revealed a significant downregulation of the key factor MAD2L2.Enhancement of MAD2L2 expression was facilitated via lentiviral vector-mediated transfection.The influence of this overexpression on TNF-α-prompted inflammation,intracellular signaling pathways,and the migratory and invasive behaviors of the colorectal cancer cells was then scrutinized.Results:TNF-αtreatment significantly increased the expression of Interleukin-1 beta(IL-1β)and Interleukin-6(IL-6),activated the MAPK p38 and PI3K/AKT signaling pathways,and enhanced cell migration and invasion.A decrease in MAD2L2 expression was observed following TNF-αtreatment.However,overexpression of MAD2L2 reversed the effects of TNF-α,reducing IL-1βand IL-6 levels,attenuating PI3K/AKT pathway activation,and inhibiting cell migration and invasion.Conclusions:Overexpression of MAD2L2 attenuates the pro-inflammatory effects of TNF-α,suggesting that MAD2L2 plays a protective role against TNF-α-induced migration and invasion of colorectal carcinoma cells.Therefore,MAD2L2 holds potential as a therapeutic target in the treatment of colorectal cancer.展开更多
It was a 36-year-old patient, 5th Pregnancy, 5th Delivery, 4 live children, and I deceased, had a consultation in the department for the removal of implants. Questioning revealed that she had had the implant three yea...It was a 36-year-old patient, 5th Pregnancy, 5th Delivery, 4 live children, and I deceased, had a consultation in the department for the removal of implants. Questioning revealed that she had had the implant three years ago without medical follow-up. It was in view of the difficulties in extracting the capsule that the chest X-ray and CT scan carried out concluded that the implant had migrated into a branch of the left pulmonary artery. Therapeutic abstention has been the attitude of cardiovascular surgeons.展开更多
Internal migration is highly valued due to its increasingly acknowledged potential for social and economic development. However, despite its significant contribution to the development of towns and cities, it has led ...Internal migration is highly valued due to its increasingly acknowledged potential for social and economic development. However, despite its significant contribution to the development of towns and cities, it has led to the deterioration of many ecosystems globally. Lake Bosomtwe, a natural Lake in Ghana and one of the six major meteoritic lakes in the world is affected by land cover changes caused by the rising effects of migration, population expansion, and urbanization, owing to the development of tourist facilities on the lakeshore. This study investigated land cover change trajectories using a post-classification comparison approach and identified the factors influencing alteration in the Lake Bosomtwe Basin. Using Landsat imagery, an integrated approach of remote sensing, geographical information systems (GIS), and statistical analysis was successfully employed to analyze the land cover change of the basin. The findings show that over the 17 years, the basin’s forest cover decreased significantly by 16.02%, indicating that population expansion significantly affects changes in land cover. Ultimately, this study will raise the awareness of stakeholders, decision-makers, policy-makers, government, and non-governmental agencies to evaluate land use development patterns, optimize land use structures, and provide a reference for the formulation of sustainable development policies to promote the sustainable development of the ecological environment.展开更多
Effect of direct current electric field (DCEF) on corrosion behaviour of copper printed circuit board (PCB-Cu), Cl-ion migration behaviour, dendrites growth under thin electrolyte layer was investigated using pote...Effect of direct current electric field (DCEF) on corrosion behaviour of copper printed circuit board (PCB-Cu), Cl-ion migration behaviour, dendrites growth under thin electrolyte layer was investigated using potentiodynamic polarization and scanning electron microscopy (SEM) with energy dispersive spectrometer (EDS). Results indicate that DCEF decreases the corrosion of PCB-Cu;Cl-ions directionally migrate from the negative pole to the positive pole, and enrich on the surface of the positive pole, which causes serious localized corrosion; dendrites grow on the surface of the negative pole, and the rate and scale of dendrite growth become faster and greater with the increase of external voltage and exposure time, respectively.展开更多
By using field trials, the migration and transformation of coated controlled release nitrogen (YZS80) in soil under the co-situs application mode were studied. The results indicated that YZS80 nitrogen dissolved out...By using field trials, the migration and transformation of coated controlled release nitrogen (YZS80) in soil under the co-situs application mode were studied. The results indicated that YZS80 nitrogen dissolved out in average speed of about 0.4%/d and 32% totally in 80 d compared with common compound fertUizer. For YZS80, in the vertical downward direction of application points, urea nitrogen content increased significantly (P 〈0.05) in the 45 -80 d and the 30 -60 cm soil layers; nitrate nitrogen content was little change range and in moderate (10 -100 mg/kg) in 0 -80 d and 10 -60 cm soil layers, but increased significantly ( P 〈0.05) 45 -80 d compared to 0 -45 d; ammonium nitrogen content was significant lower (P〈0.05) before 45 d in 10 -30 cm soil layers, but significant higher(P〈0.05) after 45 d in 10 -60 cm soil layers; NO3^- -N/NH4^+ -N meets gradually the needs of the crop with the extension of time. Under the co-situs application mode, the possibility of burning root and salt injury and loss dsk of nitrate leaching is a significant reduction.展开更多
Reverse-time migration in finite space requires effective boundary processing technology to eliminate the artificial truncation boundary effect in the migration result.On the basis of the elastic velocity-stress equat...Reverse-time migration in finite space requires effective boundary processing technology to eliminate the artificial truncation boundary effect in the migration result.On the basis of the elastic velocity-stress equations in vertical transversely isotropic media and the idea of the conventional split perfectly matched layer(PML),the PML wave equations in reverse-time migration are derived in this paper and then the high order staggered grid discrete schemes are subsequently given.Aiming at the"reflections"from the boundary to the computational domain,as well as the effect of seismic event's abrupt changes at the two ends of the seismic array,the PML arrangement in reverse-time migration is given.The synthetic and real elastic,prestack,multi-component,reverse-time depth migration results demonstrate that this method has much better absorbing effects than other methods and the joint migration produces good imaging results.展开更多
In this paper, we use the method of pseudo-offset migration (POM) to complete converted wave pre-stack time migration with amplitude-preservation in an anisotropic medium. The method maps the original traces into co...In this paper, we use the method of pseudo-offset migration (POM) to complete converted wave pre-stack time migration with amplitude-preservation in an anisotropic medium. The method maps the original traces into common conversion scatter point (CCSP) gathers directly by POM, which simplifies the conventional processing procedure for converted waves. The POM gather fold and SNR are high, which is favorable for velocity analysis and especially suitable for seismic data with low SNR. We used equivalent anisotropic theory to compute anisotropic parameters. Based on the scattering wave traveltime equation in a VTI medium, the POM pseudo-offset migration in anisotropic media was deduced. By amplitude-preserving POM gather mapping, velocity analysis, stack processing, and so on, the anisotropic migration results were acquired. The forward modeling computation and actual data processing demonstrate the validity of converted wave pre-stack time migration with amplitude-preservation using the anisotropic POM method.展开更多
基金the National Basic Research Program of China(973 Progra m,2006CB102007)the National Natural Science Foundation of China(30771385)+1 种基金National Key Technologies R&D Program of China during the 11th Five-Year Plan period(2006BAD08A01)National Public BeneficialResearch of the Ministry of Science and Technologyof China(2004DIB4J155)
文摘Vertical-looking radar (VLR) has allowed long-term automatic monitoring of the altitudinal and temporal dynamics of high- flying insect populations. To investigate whether ground beetle, insect of Coleoptera, was capable of migrating and its migration pattern by taking advantages of capability of the VLR for long-term real-time automatic monitoring, the migration of Coleoptera ground beetle was investigated by setting up radar observation points, making long-term observation using the VLR and related supplementary equipment, and analyzing low altitude air current and large area circulating current in combination with the meteorological data. Information obtained in 2005 and 2006 showed that the seasonal activities of ground beetles traps of trap lamps were mainly from late June to late August, peak period was mainly in August, seasonal traps of high-altitude lamps and ground lamps were featured by sudden increase and sudden decrease; in peak period, the height of radar echo point could be as high as 600 m, while it was mainly below the height of 450 m; night activities mainly occurred from 20:00 to 22:00, in very few nights, radar echo could last until about 04:00, changes in numbers of ground beetles within the searchlights were consistent with radar echo intensity; ground beetle images were successfully trapped in the sweep nets carried by captive balloons at the height of 200 m. Some species of Carabidaes had some degrees of migration, thus providing the foundation for investigating the migration of Coleoptera insects.
基金supported by the National Natural Science Foundation of China(No.20021024)Natural Science Foundation of Jiangxi province(No.0350011).
文摘Molecular dynamics simulations of high temperature annealing of copper bicrystals have been carried out. The bicrystals have planar grain boundaries, and the gain size varies in nano range. An EAM (embedded atom method) potential of FS type is used for calculating the interatomic forces. The results show that in nanocrystalline copper, GB migration driven by inter-GB reaction can take place. A critical grain size is identified, below which the inter-GB reaction becomes strong enough to trigger GB motion, which accelerates rapidly and leads to annihilation of the grain boundaries. The critical size is found to be 16 atomic radii. A "through intermediate grain mechanism" is identified for the nano-grain boundary motion observed, which is never reported for GB migrations of conventional polycrystalline metals.
基金supported by the National Science and Technology Major Project (No. 2016ZX05027-002)the National Natural Science Foundation of China (No. 41230 318)Qingdao National Laboratory for Marine Science and Technology Innovation Project of Ao-Shan (No. 2015ASKJ03)
文摘Ocean-Bottom Node(OBN)acquisitions provide both non-converted and converted reflection energy.There is a clear advantage to independently imaging both P-and S-waves,as they provide more information collectively than either does alone.In many conventional converted-wave pre-stack migration algorithms,density is treated as a constant,which is not the real-life case on earth.S-wave velocity and density information is crucial for hydrocarbon detection because it helps in the identification of porefilling fluids.In this paper,we focused on the effect of density on imaging,and developed a method of reverse-time migration(RTM)on converted s-waves of varying densities(VD-RTMCS).Phase correction was required prior to pre-stack migration to avoid constructive interference between data from adjacent sources.Synthetic data examples showed that when density variations were included,image profiles showed advantages in signal-to-noise ratio,vertical resolution and imaging of complex structures.
基金supported in part by NIH R01 NS100531,R01 NS103481NIH R21NS130241(to LD)+3 种基金Merit Review Award I01 BX002356,I01 BX003705 from the U.S.Department of Veterans AffairsIndiana Spinal Cord and Brain Injury Research Foundation(No.19919)Mari Hulman George Endowment Funds(to XMX)Indiana Spinal Cord&Brain Injury Research Fund from ISDH(to NKL and LD)。
文摘Schwann cell transplantation is considered one of the most promising cell-based therapy to repair injured spinal cord due to its unique growth-promoting and myelin-forming properties.A the Food and Drug Administration-approved Phase I clinical trial has been conducted to evaluate the safety of transplanted human autologous Schwann cells to treat patients with spinal cord injury.A major challenge for Schwann cell transplantation is that grafted Schwann cells are confined within the lesion cavity,and they do not migrate into the host environment due to the inhibitory barrier formed by injury-induced glial scar,thus limiting axonal reentry into the host spinal cord.Here we introduce a combinatorial strategy by suppressing the inhibitory extracellular environment with injection of lentivirus-mediated transfection of chondroitinase ABC gene at the rostral and caudal borders of the lesion site and simultaneously leveraging the repair capacity of transplanted Schwann cells in adult rats following a mid-thoracic contusive spinal cord injury.We report that when the glial scar was degraded by chondroitinase ABC at the rostral and caudal lesion borders,Schwann cells migrated for considerable distances in both rostral and caudal directions.Such Schwann cell migration led to enhanced axonal regrowth,including the serotonergic and dopaminergic axons originating from supraspinal regions,and promoted recovery of locomotor and urinary bladder functions.Importantly,the Schwann cell survival and axonal regrowth persisted up to 6 months after the injury,even when treatment was delayed for 3 months to mimic chronic spinal cord injury.These findings collectively show promising evidence for a combinatorial strategy with chondroitinase ABC and Schwann cells in promoting remodeling and recovery of function following spinal cord injury.
基金support of the National Natural Science Foundation of China(Grant No.22225801,22178217 and 22308216)supported by the Fundamental Research Funds for the Central Universities,conducted at Tongji University.
文摘Rechargeable magnesium batteries(RMBs)have been considered a promising“post lithium-ion battery”system to meet the rapidly increasing demand of the emerging electric vehicle and grid energy storage market.However,the sluggish diffusion kinetics of bivalent Mg^(2+)in the host material,related to the strong Coulomb effect between Mg^(2+)and host anion lattices,hinders their further development toward practical applications.Defect engineering,regarded as an effective strategy to break through the slow migration puzzle,has been validated in various cathode materials for RMBs.In this review,we first thoroughly understand the intrinsic mechanism of Mg^(2+)diffusion in cathode materials,from which the key factors affecting ion diffusion are further presented.Then,the positive effects of purposely introduced defects,including vacancy and doping,and the corresponding strategies for introducing various defects are discussed.The applications of defect engineering in cathode materials for RMBs with advanced electrochemical properties are also summarized.Finally,the existing challenges and future perspectives of defect engineering in cathode materials for the overall high-performance RMBs are described.
基金supported by the National Natural Science Foundation of China,Nos.82272171(to ZY),82271403(to XL),81941011(to XL),31971279(to ZY),31730030(to XL)the Natural Science Foundation of Beijing,No.7222004(to HD).
文摘The presence of endogenous neural stem/progenitor cells in the adult mammalian brain suggests that the central nervous system can be repaired and regenerated after injury.However,whether it is possible to stimulate neurogenesis and reconstruct cortical layers II to VI in non-neurogenic regions,such as the cortex,remains unknown.In this study,we implanted a hyaluronic acid collagen gel loaded with basic fibroblast growth factor into the motor cortex immediately following traumatic injury.Our findings reveal that this gel effectively stimulated the proliferation and migration of endogenous neural stem/progenitor cells,as well as their differentiation into mature and functionally integrated neurons.Importantly,these new neurons reconstructed the architecture of cortical layers II to VI,integrated into the existing neural circuitry,and ultimately led to improved brain function.These findings offer novel insight into potential clinical treatments for traumatic cerebral cortex injuries.
基金Under the auspices of the Fund of Social Sciences Research,Ministry of Education of China(No.17YJA840011)。
文摘Since China’s reform and opening-up,the growing disparity between urban and rural areas and regions has led to massive migration.With China’s Rural Revitalization Strategy and the industrial transfer from the eastern coastal areas to the inland,the migration direction and pattern of the floating population have undergone certain changes.Using the 2017 China Migrants Dynamic Survey(CMDS),excluding Hong Kong,Macao,and Taiwan regions of China,organized by China’s National Health Commission,the relationship matrix of the floating population is constructed according to the inflow place of the interviewees and their outflow place(the location of the registered residence)in the questionnaire survey.We then apply the complex network model to analyze the migration direction and network pattern of China’s floating population from the city scale.The migration network shows an obvious hierarchical agglomeration.The first-,second-,third-and fourth-tier distribution cities are municipalities directly under the central government,provincial capital cities,major cities in the central and western regions and ordinary cities in all provinces,respectively.The migration trend is from the central and western regions to the eastern coastal areas.The migration network has‘small world’characteristics,forming nine communities.It shows that most node cities in the same community are closely linked and geographically close,indicating that the migration network of floating population is still affected by geographical proximity.Narrowing the urban-rural and regional differences will promote the rational distribution this population.It is necessary to strengthen the reform of the registered residence system,so that the floating population can enjoy urban public services comparable to other populations,and allow migrants to live and work in peace.
基金supported by the National Natural Science Foundation of China(Nos.12174208 and 32227802)National Key Research and Development Program of China(No.2022YFC3400600)+2 种基金Guangdong Major Project of Basic and Applied Basic Research(No.2020B0301030009)Fundamental Research Funds for the Central Universities(Nos.2122021337 and 2122021405)the 111 Project(No.B23045).
文摘Collective cell migration is a coordinated movement of multi-cell systems essential for various processes throughout life.The collective motions often occur under spatial restrictions,hallmarked by the collective rotation of epithelial cells confined in circular substrates.Here,we aim to explore how geometric shapes of confinement regulate this collective cell movement.We develop quantitative methods for cell velocity orientation analysis,and find that boundary cells exhibit stronger tangential ordering migration than inner cells in circular pattern.Furthermore,decreased tangential ordering movement capability of collective cells in triangular and square patterns are observed,due to the disturbance of cell motion at unsmooth corners of these patterns.On the other hand,the collective cell rotation is slightly affected by a convex defect of the circular pattern,while almost hindered with a concave defect,also resulting from different smoothness features of their boundaries.Numerical simulations employing cell Potts model well reproduce and extend experimental observations.Together,our results highlight the importance of boundary smoothness in the regulation of collective cell tangential ordering migration.
基金supported by the National Natural Science Foundation of China(No.U20A20133)the Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province(No.20220207)the Fundamental Research Funds for the Provincial Universities of Zhejiang(No.2021YW63).
文摘The potential association between colorectal cancer(CRC)and environmental pollutants is worrisome.Previous studies have found that some perfluoroalkyl acids,including perfluorooctane sulfonate(PFOS),induced colorectal tumors in experimental animals and promoted the migration of and invasion by CRC cells in vitro,but the underlying mechanism is unclear.Here,we investigated the effects of PFOS on the proliferation and migration of CRC cells and the potentialmechanisms involving activating the PI3K/Akt-NF-κB signal pathway and epithelial-mesenchymal transition(EMT).It was found that PFOS promoted the growth andmigration of HCT116 cells at non-cytotoxic concentrations and increased the mRNA expression of the migration-related angiogenic cytokines vascular endothelial growth factor(VEGF)and interleukin-8(IL-8).In a mechanistic investigation,the up-stream signal pathway PI3K/Akt-NF-κB was activated by PFOS,and the process was suppressed by LY294002(PI3K/Akt inhibitor)and BAY11-7082(NF-κB inhibitor)respectively,leading to less proliferation of HCT116 cells.Furthermore,matrix metalloproteinases(MMP)and EMT-related markers were up-regulated after PFOS exposure,and were also suppressed respectively by LY294002 and BAY11-7082.Moreover,the up-regulation of EMT markers was suppressed by a MMP inhibitor GM6001.Taken together,our results indicated that PFOS promotes colorectal cancer cell migration and proliferation by activating the PI3K/Akt-NF-κB signal pathway and epithelial-mesenchymal transition.This could be a potential toxicological mechanism of PFOS-induced malignant development of colorectal cancer.
基金Supported by Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory (2019BT02H594)Sanya Technology Innovation Special Project (2022KJCX08)。
文摘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.
基金supported by the Gusu Medical Key Talent Project of Suzhou City of China(GSWS2020005)the New Pharmaceutics and Medical Apparatuses Project of Suzhou City of China(SLJ2021007)+3 种基金the Suzhou City Key Clinical Disease Diagnosis and Treatment Technology Special Project,China(LCZX202129)Wujiang Science and Educational Health Revitalization Fund Project,Suzhou,China(WWK202015)the Scientific Research Project of Suzhou Ninth People’s Hospital,Suzhou,China(YK202008)and Suzhou“Science and Education”Youth Science and Technology Project,Suzhou,China(KJXW2020075).
文摘Colorectal cancer(CRC)stands among the top prevalent cancers worldwide and holds a prominent position as a major contributor to cancer-related mortality globally.Absent in melanoma 2(AIM2),a constituent of the interferoninducible hematopoietic interferon-inducible nuclear antigens with 200 amino acid repeats protein family,contributes to both cancer progression and inflammasome activation.Despite this understanding,the precise biological functions and molecular mechanisms governed by AIM2 in CRC remain elusive.Consequently,this study endeavors to assess AIM2’s expression levels,explore its potential antitumor effects,elucidate associated cancer-related processes,and decipher the underlying signaling pathways in CRC.Our findings showed a reduced AIM2 expression in most CRC cell lines.Elevation of AIM2 levels suppressed CRC cell proliferation and migration,altered cell cycle by inhibiting G1/S transition,and induced cell apoptosis.Further research uncovered the participation of P38 mitogen-activated protein kinase(P38MAPK)in AIM2-mediated modulation of CRC cell apoptosis and proliferation.Altogether,our achievements distinctly underscored AIM2’s antitumor role in CRC.AIM2 overexpression inhibited proliferation and migration and induced apoptosis of CRC cells via activating P38MAPK signaling pathway,indicating AIM2 as a prospective and novel therapeutic target for CRC.
基金Supported by the Science and Technology Research Project of China Petroleum&Chemical Corporation (No. P22175)。
文摘The geological storage of carbon dioxide(CO_(2)) is a crucial technology for mitigating climate change. Offshore deep saline aquifers have elicited increased attention due to their remarkable potential for storing CO_(2). During long-term storage, CO_(2) migration in a deep saline aquifer needs special attention to prevent it from reaching risk points and leading to security issues. In this paper, a mechanism model is established according to the geological characteristics of saline aquifers in an offshore sedimentary basin in China. The CO_(2) migration over 100 years is simulated considering geological changes such as permeability, dip angle, thickness, and salinity. The effects of injection conditions on the CO_(2) migration range are also investigated. Results reveal that the migration range of CO_(2) in the injection period exceeds 70%, even if the postinjection period's duration is five times longer than that of the injection period. As the values of the above geological parameters increase, the migration range of CO_(2) increases, and permeability has a particularly substantial influence. Moreover, the influences of injection rate and well type are considerable. At high injection rates, CO_(2) has a greater likelihood of displacing brine in a piston-like scheme. CO_(2) injected by long horizontal wells migrates farther compared with that injected by vertical wells. In general, the plane migration range is within 3 000 m, although variations in the reservoir and injection parameters of the studied offshore saline aquifers are considered. This paper can offer references for the site selection and injection well deployment of CO_(2) saline aquifer storage. According to the studied offshore aquifers, a distance of at least 3 000 m from potential leakage points, such as spill points, active faults, and old abandoned wells, must be maintained.
基金support from the National Natural Science Foundation of China(Grant Nos.11974066,12174041,12104134,T2350007,and 12347178)the Fundamental and Advanced Research Program of Chongqing(Grant No.cstc2019jcyj-msxm X0477)+3 种基金the Natural Science Foundation of Chongqing(Grant No.CSTB2022NSCQMSX1260)the Science and Technology Research Program of Chongqing Municipal Education Commission(Grant No.KJQN202301333)the Scientific Research Fund of Chongqing University of Arts and Sciences(Grant Nos.R2023HH03 and P2022HH05)College Students’Innovation and Entrepreneurship Training Program of Chongqing Municipal(Grant No.S202310642002)。
文摘Increasing data indicate that cancer cell migration is regulated by extracellular matrixes and their surrounding biochemical microenvironment,playing a crucial role in pathological processes such as tumor invasion and metastasis.However,conventional two-dimensional cell culture and animal models have limitations in studying the influence of tumor microenvironment on cancer cell migration.Fortunately,the further development of microfluidic technology has provided solutions for the study of such questions.We utilize microfluidic chip to build a random collagen fiber microenvironment(RFM)model and an oriented collagen fiber microenvironment(OFM)model that resemble early stage and late stage breast cancer microenvironments,respectively.By combining cell culture,biochemical concentration gradient construction,and microscopic imaging techniques,we investigate the impact of different collagen fiber biochemical microenvironments on the migration of breast cancer MDA-MB-231-RFP cells.The results show that MDA-MB-231-RFP cells migrate further in the OFM model compared to the RFM model,with significant differences observed.Furthermore,we establish concentration gradients of the anticancer drug paclitaxel in both the RFM and OFM models and find that paclitaxel significantly inhibits the migration of MDA-MB-231-RFP cells in the RFM model,with stronger inhibition on the high concentration side compared to the low concentration side.However,the inhibitory effect of paclitaxel on the migration of MDA-MB-231-RFP cells in the OFM model is weak.These findings suggest that the oriented collagen fiber microenvironment resembling the late-stage tumor microenvironment is more favorable for cancer cell migration and that the effectiveness of anticancer drugs is diminished.The RFM and OFM models constructed in this study not only provide a platform for studying the mechanism of cancer development,but also serve as a tool for the initial measurement of drug screening.
基金supported by the Ningxia Hui Autonomous Region key research and development programs(Grant No.2021BEG03084)the National Natural Science Foundation of China(Grant No.31660336).
文摘Background:Colorectal cancer is a major global health concern,exacerbated by tumor necrosis factor-alpha(TNF-α)and its role in inflammation,with the effects of Mitotic Arrest Deficient 2 Like 2(MAD2L2)in this context still unclear.Methods:The colorectal carcinoma cell lines HCT116 and SW620 were exposed to TNF-αfor a period of 24 h to instigate an inflammatory response.Subsequent assessments were conducted to measure the expression of inflammatory cytokines,the activity within the p38 mitogen-activated protein kinase(p38 MAPK)and Phosphoinositide 3-Kinase/AKT Serine/Threonine Kinase pathway(PI3K/AKT)signaling cascades.Transcriptome sequencing and subsequent integrative analysis with the Cancer Genome Atlas(TCGA)program database revealed a significant downregulation of the key factor MAD2L2.Enhancement of MAD2L2 expression was facilitated via lentiviral vector-mediated transfection.The influence of this overexpression on TNF-α-prompted inflammation,intracellular signaling pathways,and the migratory and invasive behaviors of the colorectal cancer cells was then scrutinized.Results:TNF-αtreatment significantly increased the expression of Interleukin-1 beta(IL-1β)and Interleukin-6(IL-6),activated the MAPK p38 and PI3K/AKT signaling pathways,and enhanced cell migration and invasion.A decrease in MAD2L2 expression was observed following TNF-αtreatment.However,overexpression of MAD2L2 reversed the effects of TNF-α,reducing IL-1βand IL-6 levels,attenuating PI3K/AKT pathway activation,and inhibiting cell migration and invasion.Conclusions:Overexpression of MAD2L2 attenuates the pro-inflammatory effects of TNF-α,suggesting that MAD2L2 plays a protective role against TNF-α-induced migration and invasion of colorectal carcinoma cells.Therefore,MAD2L2 holds potential as a therapeutic target in the treatment of colorectal cancer.
文摘It was a 36-year-old patient, 5th Pregnancy, 5th Delivery, 4 live children, and I deceased, had a consultation in the department for the removal of implants. Questioning revealed that she had had the implant three years ago without medical follow-up. It was in view of the difficulties in extracting the capsule that the chest X-ray and CT scan carried out concluded that the implant had migrated into a branch of the left pulmonary artery. Therapeutic abstention has been the attitude of cardiovascular surgeons.
文摘Internal migration is highly valued due to its increasingly acknowledged potential for social and economic development. However, despite its significant contribution to the development of towns and cities, it has led to the deterioration of many ecosystems globally. Lake Bosomtwe, a natural Lake in Ghana and one of the six major meteoritic lakes in the world is affected by land cover changes caused by the rising effects of migration, population expansion, and urbanization, owing to the development of tourist facilities on the lakeshore. This study investigated land cover change trajectories using a post-classification comparison approach and identified the factors influencing alteration in the Lake Bosomtwe Basin. Using Landsat imagery, an integrated approach of remote sensing, geographical information systems (GIS), and statistical analysis was successfully employed to analyze the land cover change of the basin. The findings show that over the 17 years, the basin’s forest cover decreased significantly by 16.02%, indicating that population expansion significantly affects changes in land cover. Ultimately, this study will raise the awareness of stakeholders, decision-makers, policy-makers, government, and non-governmental agencies to evaluate land use development patterns, optimize land use structures, and provide a reference for the formulation of sustainable development policies to promote the sustainable development of the ecological environment.
基金Project(50871044)supported by the National Natural Science Foundation of ChinaProject(2012M511207)supported by the Postdoctoral Science Foundation of ChinaProject(10122011)supported by the Science Research Foundation of Wuhan Institute Technology,China
文摘Effect of direct current electric field (DCEF) on corrosion behaviour of copper printed circuit board (PCB-Cu), Cl-ion migration behaviour, dendrites growth under thin electrolyte layer was investigated using potentiodynamic polarization and scanning electron microscopy (SEM) with energy dispersive spectrometer (EDS). Results indicate that DCEF decreases the corrosion of PCB-Cu;Cl-ions directionally migrate from the negative pole to the positive pole, and enrich on the surface of the positive pole, which causes serious localized corrosion; dendrites grow on the surface of the negative pole, and the rate and scale of dendrite growth become faster and greater with the increase of external voltage and exposure time, respectively.
基金Supported by Beijing Science Committee Project"Science & TechnologyNew Star"(2008B38)"The Research and Establishmentof Agrochemical Service System for New Type of Fertilizer"(d0706004040431)The Foundation for Youth Scholars of BeijingAcademy of Agriculture and Forestry Sciences"The Developmentand Evaluation of Micro Water-soluble Cementation Coated Slow-releaseFertilizers Suitable for Semiand Areas"~~
文摘By using field trials, the migration and transformation of coated controlled release nitrogen (YZS80) in soil under the co-situs application mode were studied. The results indicated that YZS80 nitrogen dissolved out in average speed of about 0.4%/d and 32% totally in 80 d compared with common compound fertUizer. For YZS80, in the vertical downward direction of application points, urea nitrogen content increased significantly (P 〈0.05) in the 45 -80 d and the 30 -60 cm soil layers; nitrate nitrogen content was little change range and in moderate (10 -100 mg/kg) in 0 -80 d and 10 -60 cm soil layers, but increased significantly ( P 〈0.05) 45 -80 d compared to 0 -45 d; ammonium nitrogen content was significant lower (P〈0.05) before 45 d in 10 -30 cm soil layers, but significant higher(P〈0.05) after 45 d in 10 -60 cm soil layers; NO3^- -N/NH4^+ -N meets gradually the needs of the crop with the extension of time. Under the co-situs application mode, the possibility of burning root and salt injury and loss dsk of nitrate leaching is a significant reduction.
基金supported by the 863 Program(Grant No.2006AA06Z202)Open Fund of the Key Laboratory of Geophysical Exploration of CNPC(Grant No.GPKL0802)+1 种基金CNPC Young Innovation Fund(Grant No.05E7028)the Program for New Century Excellent Talents in University(Grant No.NCET-07-0845)
文摘Reverse-time migration in finite space requires effective boundary processing technology to eliminate the artificial truncation boundary effect in the migration result.On the basis of the elastic velocity-stress equations in vertical transversely isotropic media and the idea of the conventional split perfectly matched layer(PML),the PML wave equations in reverse-time migration are derived in this paper and then the high order staggered grid discrete schemes are subsequently given.Aiming at the"reflections"from the boundary to the computational domain,as well as the effect of seismic event's abrupt changes at the two ends of the seismic array,the PML arrangement in reverse-time migration is given.The synthetic and real elastic,prestack,multi-component,reverse-time depth migration results demonstrate that this method has much better absorbing effects than other methods and the joint migration produces good imaging results.
文摘In this paper, we use the method of pseudo-offset migration (POM) to complete converted wave pre-stack time migration with amplitude-preservation in an anisotropic medium. The method maps the original traces into common conversion scatter point (CCSP) gathers directly by POM, which simplifies the conventional processing procedure for converted waves. The POM gather fold and SNR are high, which is favorable for velocity analysis and especially suitable for seismic data with low SNR. We used equivalent anisotropic theory to compute anisotropic parameters. Based on the scattering wave traveltime equation in a VTI medium, the POM pseudo-offset migration in anisotropic media was deduced. By amplitude-preserving POM gather mapping, velocity analysis, stack processing, and so on, the anisotropic migration results were acquired. The forward modeling computation and actual data processing demonstrate the validity of converted wave pre-stack time migration with amplitude-preservation using the anisotropic POM method.