Seismic wavefields propagate through three-dimensional(3D)space,and their precise characterization is crucial for understanding subsurface structures.Traditional 2D algorithms,due to their limitations,are insufficient...Seismic wavefields propagate through three-dimensional(3D)space,and their precise characterization is crucial for understanding subsurface structures.Traditional 2D algorithms,due to their limitations,are insufficient to fully represent three-dimensional wavefields.The classic 3D Radon transform algorithm assumes that the wavefield's propagation characteristics are consistent in all directions,which often does not hold true in complex underground media.To address this issue,we present an improved 3D three-parameter Radon algorithm that considers the wavefield variation with azimuth and provides a more accurate wavefield description.However,introducing new parameters to describe the azimuthal varia-tion also poses computational challenges.The new Radon transform operator involves five variables and cannot be simply decomposed into small matrices for efficient computation;instead,it requires large matrix multiplication and inversion operations,significantly increasing the computational load.To overcome this challenge,we have integrated the curvature and frequency parameters,simplifying all frequency operators to the same,thereby significantly improving computation efficiency.Furthermore,existing transform algorithms neglect the lateral variation of seismic amplitudes,leading to discrepancies between the estimated multiples and those in the data.To enhance the amplitude preservation of the algorithm,we employ orthogonal polynomial fitting to capture the amplitude spatial variation in 3D seismic data.Combining these improvements,we propose a fast,amplitude-preserving,3D three-parameter Radon transform algorithm.This algorithm not only enhances computational efficiency while maintaining the original wavefield characteristics,but also improves the representation of seismic data by increasing amplitude fidelity.We validated the algorithm in multiple attenuation using both synthetic and real seismic data.The results demonstrate that the new algorithm significantly improves both accuracy and computational efficiency,providing an effective tool for analyzing seismic wavefields in complex subsurface structures.展开更多
BACKGROUND Hepatic stellate cell(HSC)activation is key to liver fibrosis.Targeting DNA methylation shows promise.Zebularine,a methylation inhibitor,may suppress HSC activation via the calcineurin(CaN)/NFAT3 pathway.Ma...BACKGROUND Hepatic stellate cell(HSC)activation is key to liver fibrosis.Targeting DNA methylation shows promise.Zebularine,a methylation inhibitor,may suppress HSC activation via the calcineurin(CaN)/NFAT3 pathway.Magnetic resonance imaging(MRI)is a noninvasive tool for evaluating liver fibrosis evaluation tool,but multiparametric MRI for zebularine’s effects in liver fibrosis mouse models has not been studied.AIM To clarify the anti-fibrosis mechanism and MRI-evaluated efficacy of zebularine.METHODS In vitro,transforming growth factor(TGF)-β1-stimulated human HSCs(LX-2)were treated with zebularine.α-smooth muscle actin,fibrotic and anti-fibrotic gene levels,and regulator of calcineurin1(RCAN1)regulation were measured.In vivo,carbon tetrachloride(CCl_(4))-induced liver fibrosis in mice was treated with zebularine,and fibrosis was evaluated using various biochemical,histopathological,and MRI methods.RESULTS Zebularine upregulated RCAN1.4 protein(P<0.01)and inhibited the CaN/NFAT3 pathway(P<0.05).In HSCs,TGF-β1 reduced anti-fibrotic gene massage RNA(mRNA)and increased fibrotic mRNA(P<0.05),whereas zebularine had the opposite effects(P<0.01,P<0.05).CCl4-treated mice exhibited increases in various fibrosis-related indices,all of which were reversed by zebularine treatment(P<0.05).CONCLUSION Zebularine may reduce LX-2 activation and extracellular matrix deposition via RCAN1.4 and CaN/NFAT3 path-ways.Multiparametric MRI can assess its efficacy,suggesting zebularine’s potential as a liver fibrosis treatment.展开更多
基金supported in part by National Natural Science Foundation of China(NSFC)under grant 42274139in part by the R&D Department of China National Petroleum Corporation(Investigations on fundamental experiments and advanced theoretical methods in geophysical prospecting applications,2022DQ0604-03).
文摘Seismic wavefields propagate through three-dimensional(3D)space,and their precise characterization is crucial for understanding subsurface structures.Traditional 2D algorithms,due to their limitations,are insufficient to fully represent three-dimensional wavefields.The classic 3D Radon transform algorithm assumes that the wavefield's propagation characteristics are consistent in all directions,which often does not hold true in complex underground media.To address this issue,we present an improved 3D three-parameter Radon algorithm that considers the wavefield variation with azimuth and provides a more accurate wavefield description.However,introducing new parameters to describe the azimuthal varia-tion also poses computational challenges.The new Radon transform operator involves five variables and cannot be simply decomposed into small matrices for efficient computation;instead,it requires large matrix multiplication and inversion operations,significantly increasing the computational load.To overcome this challenge,we have integrated the curvature and frequency parameters,simplifying all frequency operators to the same,thereby significantly improving computation efficiency.Furthermore,existing transform algorithms neglect the lateral variation of seismic amplitudes,leading to discrepancies between the estimated multiples and those in the data.To enhance the amplitude preservation of the algorithm,we employ orthogonal polynomial fitting to capture the amplitude spatial variation in 3D seismic data.Combining these improvements,we propose a fast,amplitude-preserving,3D three-parameter Radon transform algorithm.This algorithm not only enhances computational efficiency while maintaining the original wavefield characteristics,but also improves the representation of seismic data by increasing amplitude fidelity.We validated the algorithm in multiple attenuation using both synthetic and real seismic data.The results demonstrate that the new algorithm significantly improves both accuracy and computational efficiency,providing an effective tool for analyzing seismic wavefields in complex subsurface structures.
基金Supported by the Health Research Foundation of Hunan Provincial Health Commission,No.W20243192Natural Science Foundation of Changsha,No.kq2403086+1 种基金National Natural Science Foundation of China,No.81571784Hunan Provincial Health Commission Hunan Provincial High-level Health Talent Major Scientific Research Project,No.R2023022.
文摘BACKGROUND Hepatic stellate cell(HSC)activation is key to liver fibrosis.Targeting DNA methylation shows promise.Zebularine,a methylation inhibitor,may suppress HSC activation via the calcineurin(CaN)/NFAT3 pathway.Magnetic resonance imaging(MRI)is a noninvasive tool for evaluating liver fibrosis evaluation tool,but multiparametric MRI for zebularine’s effects in liver fibrosis mouse models has not been studied.AIM To clarify the anti-fibrosis mechanism and MRI-evaluated efficacy of zebularine.METHODS In vitro,transforming growth factor(TGF)-β1-stimulated human HSCs(LX-2)were treated with zebularine.α-smooth muscle actin,fibrotic and anti-fibrotic gene levels,and regulator of calcineurin1(RCAN1)regulation were measured.In vivo,carbon tetrachloride(CCl_(4))-induced liver fibrosis in mice was treated with zebularine,and fibrosis was evaluated using various biochemical,histopathological,and MRI methods.RESULTS Zebularine upregulated RCAN1.4 protein(P<0.01)and inhibited the CaN/NFAT3 pathway(P<0.05).In HSCs,TGF-β1 reduced anti-fibrotic gene massage RNA(mRNA)and increased fibrotic mRNA(P<0.05),whereas zebularine had the opposite effects(P<0.01,P<0.05).CCl4-treated mice exhibited increases in various fibrosis-related indices,all of which were reversed by zebularine treatment(P<0.05).CONCLUSION Zebularine may reduce LX-2 activation and extracellular matrix deposition via RCAN1.4 and CaN/NFAT3 path-ways.Multiparametric MRI can assess its efficacy,suggesting zebularine’s potential as a liver fibrosis treatment.
