One-dimensional nuclear magnetic resonance （1D NMR） logging technology is limited for fluid typing, while two-dimensional nuclear magnetic resonance （2D NMR） logging can provide more parameters including longitudi...One-dimensional nuclear magnetic resonance （1D NMR） logging technology is limited for fluid typing, while two-dimensional nuclear magnetic resonance （2D NMR） logging can provide more parameters including longitudinal relaxation time （71） and transverse relaxation time （T2） relative to fluid types in porous media. Based on the 2D NMR relaxation mechanism in a gradient magnetic field, echo train simulation and 2D NMR inversion are discussed in detail. For 2D NMR inversion, a hybrid inversion method is proposed based on the damping least squares method （LSQR） and an improved truncated singular value decomposition （TSVD） algorithm. A series of spin echoes are first simulated with multiple waiting times （Tws） in a gradient magnetic field for given fluid models and these synthesized echo trains are inverted by the hybrid method. The inversion results are consistent with given models. Moreover, the numerical simulation of various fluid models such as the gas-water, light oil-water, and vicious oil-water models were carried out with different echo spacings （TEs） and Tws by this hybrid method. Finally, the influences of different signal-to-noise ratios （SNRs） on inversion results in various fluid models are studied. The numerical simulations show that the hybrid method and optimized observation parameters are applicable to fluid typing of gas-water and oil-water models.展开更多
Theranostic nanodrugs combining magnetic resonance imaging(MRI)and cancer therapy have attracted extensive interest in cancer diagnosis and treatment.Herein,a manganese(Mn)-doped mesoporous polydopamine(Mn-MPDA)nanodr...Theranostic nanodrugs combining magnetic resonance imaging(MRI)and cancer therapy have attracted extensive interest in cancer diagnosis and treatment.Herein,a manganese(Mn)-doped mesoporous polydopamine(Mn-MPDA)nanodrug incorporating the nitric oxide(NO)prodrug BNN6 and immune agonist R848 was developed.The nanodrug responded to the H^(+)and glutathione being enriched in tumor microenvironment to release R848 and Mn^(2+).The abundant Mn^(2+)produced through a Fenton-like reaction enabled a highly sensitive T1-T2 dual-mode MRI for monitoring the tumor accumulation process of the nanodrug,based on which an MRI-guided laser irradiation was achieved to trigger the NO gas therapy.Meanwhile,R848 induced the re-polarization of tumor-promoting M2-like macrophage to a tumoricidal M1 phenotype.Consequently,a potent synergistic antitumor effect was realized in mice bearing subcutaneous 4T1 breast cancer,which manifested the great promise of this multifunctional nanoplatform in cancer treatment.展开更多
基金sponsored by the National Natural Science Foundation of China(41172130)the Fundamental Research Funds for the Central Universities(2-9-2012-48)+1 种基金the National Major Projects(No.2011ZX05014-001)CNPC Innovation Foundation(No.2011D-5006-0305)
文摘One-dimensional nuclear magnetic resonance （1D NMR） logging technology is limited for fluid typing, while two-dimensional nuclear magnetic resonance （2D NMR） logging can provide more parameters including longitudinal relaxation time （71） and transverse relaxation time （T2） relative to fluid types in porous media. Based on the 2D NMR relaxation mechanism in a gradient magnetic field, echo train simulation and 2D NMR inversion are discussed in detail. For 2D NMR inversion, a hybrid inversion method is proposed based on the damping least squares method （LSQR） and an improved truncated singular value decomposition （TSVD） algorithm. A series of spin echoes are first simulated with multiple waiting times （Tws） in a gradient magnetic field for given fluid models and these synthesized echo trains are inverted by the hybrid method. The inversion results are consistent with given models. Moreover, the numerical simulation of various fluid models such as the gas-water, light oil-water, and vicious oil-water models were carried out with different echo spacings （TEs） and Tws by this hybrid method. Finally, the influences of different signal-to-noise ratios （SNRs） on inversion results in various fluid models are studied. The numerical simulations show that the hybrid method and optimized observation parameters are applicable to fluid typing of gas-water and oil-water models.
基金supported by the National Natural Science Foundation of China(Nos.51933011 and 31971296)the Key Areas Research and Development Program of Guangzhou(No.202007020006)+3 种基金Guangdong Basic and Applied Basic Research Foundation(No.2020A1515010523)Guangzhou Science and Technology Bureau(No.202102010181)Guangdong Provincial Key Laboratory of Sensing Technology and Biomedical Instrument(Sun Yat-sen University,No.2020B1212060077)approved by the Institutional Animal Care and Use Committee at Sun Yat-sen University(SYSU-IACUC-2021-000225).
文摘Theranostic nanodrugs combining magnetic resonance imaging(MRI)and cancer therapy have attracted extensive interest in cancer diagnosis and treatment.Herein,a manganese(Mn)-doped mesoporous polydopamine(Mn-MPDA)nanodrug incorporating the nitric oxide(NO)prodrug BNN6 and immune agonist R848 was developed.The nanodrug responded to the H^(+)and glutathione being enriched in tumor microenvironment to release R848 and Mn^(2+).The abundant Mn^(2+)produced through a Fenton-like reaction enabled a highly sensitive T1-T2 dual-mode MRI for monitoring the tumor accumulation process of the nanodrug,based on which an MRI-guided laser irradiation was achieved to trigger the NO gas therapy.Meanwhile,R848 induced the re-polarization of tumor-promoting M2-like macrophage to a tumoricidal M1 phenotype.Consequently,a potent synergistic antitumor effect was realized in mice bearing subcutaneous 4T1 breast cancer,which manifested the great promise of this multifunctional nanoplatform in cancer treatment.
