16 results on '"Dai, Liqun"'
Search Results
2. A bioorthogonal cell sorting strategy for isolation of desired cell phenotypes.
- Author
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Dai, Liqun, Zhou, Siming, Yang, Cheng, Li, Jie, Wang, Yayue, Qin, Meng, Pan, Lili, Zhang, Dan, Qian, Zhiyong, and Wu, Haoxing
- Abstract
Here we describe a cost-effective and simplified cell sorting method using tetrazine bioorthogonal chemistry. We successfully isolated SKOV3 cells from complex mixtures, demonstrating efficacy in separating mouse lymphocytes expressing interferon and HeLa cells expressing virally transduced green fluorescent protein post-infection. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. BPA‐Containing Polydopamine Nanoparticles for Boron Neutron Capture Therapy in a U87 Glioma Orthotopic Model.
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Dai, Liqun, Liu, Jie, Zhao, Xiaosheng, Li, Yuhao, Zhou, Siming, Yuan, Liping, Shu, Diyun, Pan, Lili, Liu, Yuan‐hao, and Qian, Zhiyong
- Subjects
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BORON-neutron capture therapy , *GLIOMAS , *NANOPARTICLES - Abstract
Boron neutron capture therapy (BNCT) is a promising therapy for refractory cancer based on the cytotoxic reaction of 10B (n, α) 7Li. Although two BNCT agents are clinically available, they are quickly metabolized and show modest enrichment in tumor sites, partially limiting BNCT widespread application. Consequently, novel agents that perform active targeting and show good biocompatibility have to be developed. Herein, boronophenylalanine‐containing polydopamine (B‐PDA) nanoparticles are easily fabricated by encapsulating boronophenylalanine (BPA) in polydopamine via nitrogen‐boronate coordination. In this study, B‐PDA achieves increased tumor accumulation and prolonged retention effects in the tumor site and superior antitumor activity post neutron irradiation in the orthotopic xenograft glioma model. In brief, this study offers a novel strategy for BPA delivery and may broaden the perspective on nanomedicine design for BNCT. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
4. A facile boronophenylalanine modified polydopamine dual drug-loaded nanoparticles for enhanced anti-tumor immune response in hepatocellular carcinoma comprehensive treatment.
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Yang, Fan, Dai, Liqun, Shi, Kun, Liu, Qingya, Pan, Meng, Mo, Dong, Deng, Hanzhi, Yuan, Liping, Lu, Yi, Pan, Lili, Yang, Tingyu, and Qian, Zhiyong
- Subjects
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HEPATOCELLULAR carcinoma , *IMMUNE response , *CPG nucleotides , *IMMUNOLOGIC memory , *TUMOR antigens , *DOXORUBICIN , *DOPAMINE - Abstract
Hepatocellular carcinoma (HCC) has an insidious onset and high malignancy. Most patients have progressed to intermediate and advanced stages by the time of diagnosis, and the long-term efficacy of traditional treatments is not satisfactory. Immunotherapy has shown great promise in the treatment of HCC in recent years; however, the low immunogenicity and severe immunosuppressive tumor microenvironment result in a low response rate to immunotherapy in HCC patients. Therefore, it is of great significance to improve the immunogenicity of HCC and thus enhance its sensitivity to immunotherapy. Here, we prepared the boronophenylalanine-modified dual drug-loaded polydopamine nanoparticles by a facile method. This system used boronophenylalanine-modified polydopamine nanoparticles as a delivery vehicle and photothermal material for the chemotherapeutic drug doxorubicin and the immune agonist CpG oligodeoxynucleotides (CpG-ODN), with both active targeting and lysosomal escape functions. The cancer cells are rapidly killed by photothermal treatment, and then chemotherapy is used to further kill cancer cells that are inadequately treated by photothermal treatment. The combination of photothermal-chemotherapy synergistically induces the release of relevant antigens from tumor cells, thus initiating anti-tumor immunity; and then cooperates with CpG-ODN to trigger a powerful anti-tumor immune memory effect, potently and durably inhibiting HCC recurrence. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
5. Two types of the crust-mantle interaction in continental subduction zones.
- Author
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Zhao, ZiFu, Dai, LiQun, and Zheng, YongFei
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CRUST of the earth , *EARTH'S mantle , *SUBDUCTION zones , *IGNEOUS rocks , *GEOLOGICAL time scales , *GEOCHEMISTRY - Abstract
Plate subduction is an important mechanism for exchanging the mass and energy between the mantle and the crust, and the igneous rocks in subduction zones are the important carriers for studying the recycling of crustal materials and the crust-mantle interaction. This study presents a review of geochronology and geochemistry for postcollisional mafic igneous rocks from the Hong'an-Dabie-Sulu orogens and the southeastern edge of the North China Block. The available results indicate two types of the crust-mantle interaction in the continental subduction zone, which are represented by two types of mafic igneous rocks with distinct geochemical compositions. The first type of rocks exhibit arc-like trace element distribution patterns (i.e. enrichment of LILE, LREE and Pb, but depletion of HFSE) and enriched radiogenic Sr-Nd isotope compositions, whereas the second type of rocks show OIB-like trace element distribution patterns (i.e. enrichment of LILE and LREE, but no depletion of HFSE) and depleted radiogenic Sr-Nd isotope compositions. Both of them have variable zircon O isotope compositions, which are different from those of the normal mantle zircon, and contain residual crustal zircons. These geochemical features indicate that the two types of mafic igneous rocks were originated from the different natures of mantle sources. The mantle source for the second type of rocks would be generated by reaction of the overlying juvenile lithospheric mantle with felsic melts originated from previously subducted oceanic crust, whereas the mantle source for the first type of rocks would be generated by reaction of the overlying ancient lithospheric mantle of the North China Block with felsic melts from subsequently subducted continental crust of the South China Block. Therefore, there exist two types of the crust-mantle interaction in the continental subduction zone, and the postcollisional mafic igneous rocks provide petrological and geochemical records of the slab-mantle interactions in continental collision orogens. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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6. Gold Nanorods and Polymer Micelles Mediated Dual TLR Stimulators Delivery System CPG@Au NRs/M‐R848 Regulate Macrophages Reprogramming and DC Maturation for Enhanced Photothermal Immunotherapy of Melanoma.
- Author
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Jia, YanPeng, Shi, Kun, Dai, LiQun, He, XinLong, Deng, HanZhi, Han, RuXia, Yang, Fan, Chu, BingYang, Liao, JinFeng, Wei, XiaWei, and Qian, ZhiYong
- Abstract
Synergistic photothermal immunotherapy has emerged as a favorable therapeutic approach to fight cancer. However, design of an effective photothermal immunotherapy system to suppress tumor growth and simultaneously inhibit tumor metastases continues to be a challenge. Here a dual toll‐like receptor agonists delivery system CPG@Au NRs/m‐R848 for combined photothermal immunotherapy of melanoma is developed. CPG@Au NRs/m‐R848 displays strong antitumor effects by promoting maturation of dendritic cells (DCs) and reprogramming of M2 macrophages into M1 phenotype. Moreover, immunogenic cell death (ICD) induced by photothermal ablation of Au NRs could synergistically produce in situ vaccination effect with CPG ODN and R848, generating systemic and lasting antitumor immunity. It is further proved that CPG@Au NRs/m‐R848 treatment inhibits tumor growth in bilateral B16F10 tumors model by eliciting CD8+ T cell response. Overall, this work suggests that this strategy hold great potential in tumor immunotherapy by regulating tumor‐associated macrophage polarization, triggering DCs maturation and inducing ICD. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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7. A General Strategy to Design Highly Fluorogenic Far‐Red and Near‐Infrared Tetrazine Bioorthogonal Probes.
- Author
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Mao, Wuyu, Tang, Jie, Dai, Liqun, He, Xinyu, Li, Jie, Cai, Larry, Liao, Ping, Jiang, Ruotian, Zhou, Jingwei, and Wu, Haoxing
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TETRAZINE , *STOKES shift , *ORGANELLES , *RED , *PYRIDAZINES , *FLUORESCENCE - Abstract
Highly fluorogenic tetrazine bioorthogonal probes emitting at near‐infrared wavelengths are in strong demand for biomedical imaging applications. Herein, we have developed a strategy for forming a palette of novel Huaxi‐Fluor probes in situ, whose fluorescence increases hundreds of times upon forming the bioorthogonal reaction product, pyridazine. The resulting probes show large Stokes shifts and high quantum yields. Manipulating the conjugate length and pull–push strength in the fluorophore skeleton allows the emission wavelength to be fine‐tuned from 556 to 728 nm. The highly photo‐stable and biocompatible probes are suitable for visualizing organelles in live cells without a washing step and for imaging of tumors in live small animals to depths of 500 μm by two‐photon excitation. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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8. A General Strategy to Design Highly Fluorogenic Far‐Red and Near‐Infrared Tetrazine Bioorthogonal Probes.
- Author
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Mao, Wuyu, Tang, Jie, Dai, Liqun, He, Xinyu, Li, Jie, Cai, Larry, Liao, Ping, Jiang, Ruotian, Zhou, Jingwei, and Wu, Haoxing
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TETRAZINE , *STOKES shift , *ORGANELLES , *RED , *PYRIDAZINES , *FLUORESCENCE - Abstract
Highly fluorogenic tetrazine bioorthogonal probes emitting at near‐infrared wavelengths are in strong demand for biomedical imaging applications. Herein, we have developed a strategy for forming a palette of novel Huaxi‐Fluor probes in situ, whose fluorescence increases hundreds of times upon forming the bioorthogonal reaction product, pyridazine. The resulting probes show large Stokes shifts and high quantum yields. Manipulating the conjugate length and pull–push strength in the fluorophore skeleton allows the emission wavelength to be fine‐tuned from 556 to 728 nm. The highly photo‐stable and biocompatible probes are suitable for visualizing organelles in live cells without a washing step and for imaging of tumors in live small animals to depths of 500 μm by two‐photon excitation. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
9. Post-collisional mafic magmatism: Record of lithospheric mantle evolution in continental orogenic belt.
- Author
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Xu, Wenliang, Zhao, Zifu, and Dai, Liqun
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MAFIC rocks , *PLATE tectonics , *IGNEOUS rocks , *OROGENIC belts , *MAGMATISM , *OROGENY - Abstract
In order to better understand the role of post-collisional mafic magmatism at convergent plate boundaries in revealing the earth's evolution, this paper has systematically summarized the research history of post-collisional mafic magmatism, different types of collision and their influence on the nature of orogenic mantle, the concept and implication of post-collisional magmatism, and the relationship between post-collisional mafic magmatism and orogenic mantle evolution and mineralization. Post-collisional mafic igneous rocks are not only the direct records for studying the nature and evolution of orogenic mantle, but also the important carriers for regional mineralization. However, the type and quantity of the crustal materials involved in modifying the overlying lithospheric mantle during collisional orogeny, the process and mechanism of such modification, and the major control factors and mechanism of mafic magmatism-related mineralization during the post-collisional period are the main contents and direction of future researches in this field. Therefore, the study of post-collisional mafic magmatism is of significant implications for developing the theory of plate tectonics. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
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10. Meta-analysis of the effectiveness of cold therapy after total knee arthroplasty.
- Author
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Liu Yu, Zhang Nanxin, Dai Liqun, and Ying Wei
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TOTAL knee replacement , *COLD therapy , *POSTOPERATIVE pain , *PAIN tolerance , *RANGE of motion of joints , *META-analysis , *TRANSVERSUS abdominis muscle , *RANDOMIZED controlled trials - Abstract
BACKGROUND: The use of cold therapy to promote rehabilitation after total knee arthroplasty has a certain theoretical basis, but whether cold therapy can reduce bleeding, reduce pain, and promote early recovery of activity is still controversial. OBJECTIVE: To evaluate the effectiveness of cold therapy in total knee arthroplasty in reducing postoperative bleeding, reducing pain, and promoting recovery of motion range using meta-analysis. METHODS: Medline, EMBASE, Cochrane, China Biomedical Literature Database, CNKI, Wanfang and other databases were searched to find randomized controlled trials of cold therapy and other rehabilitation therapies after total knee arthroplasty. Data ware extracted. Statistical analysis was performed using Revman 5.3. Effect values were combined. RESULTS AND CONCLUSION: (1) A total of 10 randomized controlled trials were included, including 1 070 patients. The experimental group received cold therapy after total knee arthroplasty, and the control group received other rehabilitation therapies. (2) Meta-analysis showed that compared with other rehabilitation therapies, cold therapy after replacement alleviated postoperative pain [MD=-0. 75, 95%C/ (-1.29, -0.21 ), P=0.006], reduced hemoglobin drop [MlP-12.11, 95%C/ (-17.66, -6.56), P < 0.000 1]. However, cold therapy could not reduce the amount of opioids usage [MD=0.01, 95%C/ (-0.15, -0.16), P=0.92], or improve joint motion range [MD=6.58, 95%C/ (-0.54, 13. 70), P=0.07]. (3) The results show that the application of cold therapy after total knee arthroplasty can effectively relieve pain and reduce the drop of postoperative hemoglobin, but has no significant effect on reducing the application of opioid analgesics or improving motion range. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
11. Gold Nanorods and Polymer Micelles Mediated Dual TLR Stimulators Delivery System CPG@Au NRs/M‐R848 Regulate Macrophages Reprogramming and DC Maturation for Enhanced Photothermal Immunotherapy of Melanoma (Small Methods 5/2023).
- Author
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Jia, YanPeng, Shi, Kun, Dai, LiQun, He, XinLong, Deng, HanZhi, Han, RuXia, Yang, Fan, Chu, BingYang, Liao, JinFeng, Wei, XiaWei, and Qian, ZhiYong
- Published
- 2023
- Full Text
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12. Tin-polymetallic mineralization and granitic rocks in the Nanling daping mining area: Geochemical and geochronological constraints.
- Author
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Zhang, Zunzun, Lu, Youyue, Li, Jianfeng, Quan, Hongyan, Dai, Liqun, Fu, Jianming, Yu, Yushuai, Lin, Dongyong, and Dai, Pingyun
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ALKALINE earth metals , *GRANITE , *RARE earth metals , *RUBIDIUM , *NONFERROUS metals , *SEDIMENTARY rocks , *METAMORPHIC rocks - Abstract
[Display omitted] • The formation age of the Daping tin deposit belongs to the early Yanshanian. • The Daishiyan pluton underwent early-stage melting of basic rocks and crustal materials, with the latter predominating in the later stages. • Elements such as F, B, Li, etc., act as fluxing agents to promote the enrichment and mineralization of rare metals. The Daping polymetallic deposit in the Nanling is a recently discovered deposit with significant potential in the Dayishan area. High-precision geochronological studies indicate that the emplacement ages of two fine-grained porphyritic (containing tourmaline) biotite granite units are 153.2 ± 0.9 Ma and 152.3 ± 1.0 Ma, representing products of the fifth magmatic activity in the Dayishan intrusion. The cassiterite U-Pb ages from the residual skarn type and greisen-type tin ores are 153.4 ± 3.6 Ma and 150.22 ± 0.37 Ma, respectively, and they are consistent within the error range, both belonging to the Yanshanian Early period. Petrogeochemical analyses of the granite reveal characteristics of high silica content (73.56 ∼ 75.91 %), alkali (K 2 O = 4.04 ∼ 5.58 %, Na 2 O = 2.22 ∼ 3.67 %), low calcium (0.42 ∼ 0.80 %), low magnesium (0.075 ∼ 0.29 %), and peraluminous nature (A/CNK = 1.26 ∼ 1.35). The rare earth element (REE) contents range from 35.78 × 10-6 to 111.57 × 10-6, with δEu values between 0.006 and 0.026, LREE/HREE ratios of 2.23 ∼ 3.41, and (La/Yb) N values of 1.20 ∼ 2.42. The granite is enriched in elements such as Rb, K, Th, U, Nd, Hf, and depleted in Ba, Sr, P, Nb, Ti, indicating strong crystal differentiation in the area. Sr, Nd, and Hf isotope studies show that the granite samples have I Sr values of 0.67612–0.70040, ε Nd (t) values of −5.83 ∼ -8.23, ε Hf (t) values of −6.1 ∼ -1.9, (Nd)T DM2 values ranging from 1361 to 1573 Ma, and (Hf)T DM2 values ranging from 1147 to 1408 Ma. It is proposed that the Dayishan intrusion originated from the mixing of a mid-Paleoproterozoic mafic rock and a metamorphic sedimentary source region, with the latter being predominant. The detachment of source rocks from the mantle reservoir occurred in the mid-Paleoproterozoic. Combining lithological, petrogeochemical, and comparative analyses, it is classified as a highly fractionated A-type granite formed in a local extensional setting related to the subduction of the Pacific Plate. Additionally, this paper constructs a ore-forming model for the Daping tin deposit, aiming to provide reference for regional rare metal ore exploration. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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13. Tectonic evolution of convergent plate margins and its geological effects.
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Zheng, Yongfei, Chen, Yixiang, Chen, Renxu, and Dai, Liqun
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SUBDUCTION zones , *GEODYNAMICS , *EARTH system science , *CONVERGENT evolution , *PLATE tectonics , *LITHOSPHERE , *OROGENIC belts - Abstract
Oceanic lithosphere is generated at divergent plate boundaries and disappears at convergent plate boundaries. Seafloor spreading and plate subduction together constitute the physical coupling and mass conservation relationships to the movement of lithospheres on Earth. Subduction zones are a key site for the transfer of both matter and energy at converging plate boundaries, and their study has been the hot spot and frontier of Earth system science since the development of plate tectonics theory. As far as the dynamic regime and geothermal gradient of convergent plate margins are concerned, they have different properties in different stages of the subduction zone evolution. In general, the early low-angle subduction leads to compressional tectonism dominated by low geothermal gradients at the plate interface, and the late high-angle subduction results in extensional tectonism dominated by high geothermal gradients at the plate interface and its hanging wall. Active rifts are produced along suture zones through not only slab rollback or slab breakoff in the terminal stage of oceanic subduction but also foundering and thinning of the lithosphere in the post-subduction stage. Due to the differences and changes in the geometric and thermobaric structures of convergent plate margins, a series of changes in the type of metamorphism and magmatism can occur in active and fossil subduction zones. Dehydration and melting of the subducting oceanic crust are prominent at subarc depths, giving rise to fluids that dissolve different concentrations of fluid-mobile incompatible elements. The subduction zone fluids at subarc depths would chemically react with the overlying mantle wedge peridotite, generating metasomatites as the mantle sources of mafic magmas in oceanic and continental arcs. However, these metasomatites did not partially melt immediately upon the fluid metasomatism to trigger arc magmatism, and they did not melt until they were heated by asthenospheric convection due to rollback of the subducting slab. Therefore, recognition of the changes in the dynamic regime and geothermal gradient of subduction zones in different stages of plate convergence not only provides insights into geodynamic mechanisms of the tectonic evolution from subduction zones to orogenic belts, but also places constraints on the formation and evolution of different types of metamorphic and magmatic rocks within the advanced framework of plate tectonics. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
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14. Developing plate tectonics theory from oceanic subduction zones to collisional orogens.
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Zheng, YongFei, Chen, YiXiang, Dai, LiQun, and Zhao, ZiFu
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PLATE tectonics , *SUBDUCTION , *OROGENIC belts , *METAMORPHISM (Geology) , *MAGMATISM , *LITHOSPHERE - Abstract
Crustal subduction and continental collision is the core of plate tectonics theory. Understanding the formation and evolution of continental collision orogens is a key to develop the theory of plate tectonics. Different types of subduction zones have been categorized based on the nature of subducted crust. Two types of collisional orogens, i.e. arc-continent and continent-continent collisional orogens, have been recognized based on the nature of collisional blocks and the composition of derivative rocks. Arc-continent collisional orogens contain both ancient and juvenile crustal rocks, and reworking of those rocks at the post-collisional stage generates magmatic rocks with different geochemical compositions. If an orogen is built by collision between two relatively old continental blocks, post-collisional magmatic rocks are only derived from reworking of the old crustal rocks. Collisional orogens undergo reactivation and reworking at action of lithosphere extension, with inheritance not only in the tectonic regime but also in the geochemical compositions of reworked products (i.e., magmatic rocks). In order to unravel basic principles for the evolution of continental tectonics at the post-collisional stages, it is necessary to investigate the reworking of orogenic belts in the post-collisional regime, to recognize physicochemical differences in deep continental collision zones, and to understand petrogenetic links between the nature of subducted crust and post-collisional magmatic rocks. Afterwards we are in a position to build the systematics of continental tectonics and thus to develop the plate tectonics theory. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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15. Mesozoic mafic magmatism in North China: Implications for thinning and destruction of cratonic lithosphere.
- Author
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Zheng, Yongfei, Xu, Zheng, Zhao, Zifu, and Dai, Liqun
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MESOZOIC Era , *LITHOSPHERE , *MAGMATISM , *CRETACEOUS Period - Abstract
The North China Craton (NCC) has been thinned from >200 km to <100 km in its eastern part. The ancient subcontinental lithospheric mantle (SCLM) has been replaced by the juvenile SCLM in the Meoszoic. During this period, the NCC was destructed as indicated by extensive magmatism in the Early Cretaceous. While there is a consensus on the thinning and destruction of cratonic lithosphere in North China, it has been hotly debated about the mechanism of cartonic destruction. This study attempts to provide a resolution to current debates in the view of Mesozoic mafic magmatism in North China. We made a compilation of geochemical data available for Mesozoic mafic igneous rocks in the NCC. The results indicate that these mafic igneous rocks can be categorized into two series, manifesting a dramatic change in the nature of mantle sources at ~121 Ma. Mafic igneous rocks emplaced at this age start to show both oceanic island basalts (OIB)-like trace element distribution patterns and depleted to weakly enriched Sr-Nd isotope compositions. In contrast, mafic igneous rocks emplaced before and after this age exhibit both island arc basalts (IAB)-like trace element distribution patterns and enriched Sr-Nd isotope compositions. This difference indicates a geochemical mutation in the SCLM of North China at ~121 Ma. Although mafic magmatism also took place in the Late Triassic, it was related to exhumation of the deeply subducted South China continental crust because the subduction of Paleo-Pacific slab was not operated at that time. Paleo-Pacific slab started to subduct beneath the eastern margin of Eruasian continent since the Jurrasic. The subducting slab and its overlying SCLM wedge were coupled in the Jurassic, and slab dehydration resulted in hydration and weakening of the cratonic mantle. The mantle sources of ancient IAB-like mafic igneous rocks are a kind of ultramafic metasomatites that were generated by reaction of the cratonic mantle wedge peridotite not only with aqueous solutions derived from dehydration of the subducting Paleo-Pacific oceanic crust in the Jurassic but also with hydrous melts derived from partial melting of the subducting South China continental crust in the Triassic. On the other hand, the mantle sources of juvenile OIB-like mafic igneous rocks are also a kind of ultramafic metasomatites that were generated by reaction of the asthenospheric mantle underneath the North China lithosphere with hydrous felsic melts derived from partial melting of the subducting Paleo-Pacific oceanic crust. The subducting Paleo-Pacific slab became rollback at ~144 Ma. Afterwards the SCLM base was heated by laterally filled asthenospheric mantle, leading to thinning of the hydrated and weakened cratonic mantle. There was extensive bimodal magmatism at 130 to 120 Ma, marking intensive destruction of the cratonic lithosphere. Not only the ultramafic metasomatites in the lower part of the cratonic mantle wedge underwent partial melting to produce mafic igneous rocks showing negative
ε Nd(t ) values, depletion in Nb and Ta but enrichment in Pb, but also the lower continent crust overlying the cratonic mantle wedge was heated for extensive felsic magmatism. At the same time, the rollback slab surface was heated by the laterally filled asthenospheric mantle, resulting in partial melting of the previously dehydrated rocks beyond rutile stability on the slab surface. This produce still hydrous felsic melts, which metasomatized the overlying asthenospheric mantle peridotite to generate the ultramafic metasomatites that show positiveε Nd(t ) values, no depletion or even enrichment in Nb and Ta but depletion in Pb. Partial melting of such metasomatites started at ~121 Ma, giving rise to the mafic igneous rocks with juvenile OIB-like geochemical signatures. In this context, the age of ~121 Ma may terminate replacement of the ancient SCLM by the juvenile SCLM in North China. Paleo-Pacific slab was not subducted to the mantle transition zone in the Mesozoic as revealed by modern seismic tomography, and it was subducted at a low angle since the Jurassic, like the subduction of Nazca Plate beneath American continent. This flat subduction would not only chemically metasomatize the cratonic mantle but also physically erode the cratonic mantle. Therefore, the interaction between Paleo-Pacific slab and the cratonic mantle is the first-order geodynamic mechanism for the thinning and destruction of cratonic lithosphere in North China. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
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16. Heme oxygenase-1 dependant pathway contributes to protection by tetramethylpyrazine against chronic hypoxic injury on medulla oblongata in rats.
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Ding, Yan, Hou, Xuefei, Chen, Li, Zhou, Hua, Gong, Yanju, Dai, Liqun, and Zheng, Yu
- Subjects
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MEDULLA oblongata , *HYPOGLOSSAL nerve , *CHRONIC diseases , *HEME oxygenase , *PYRAZINES , *HERBAL medicine , *THERAPEUTICS - Abstract
Tetramethylpyrazine (TMP), one of the active ingredients of the Chinese herb Lingusticum Wallichii (Chuan Xiong) has been proved to protect the medulla oblongata from chronic hypoxia injury. However, the underlying mechanism remains unclear. The purpose of this study was to determine whether the protective effects of TMP are associated with the heme oxygenase-1 (HO-1) dependant pathway in adult rats. The morphological changes of neurons in the hypoglossal nucleus (12N), the nucleus ambiguus (Amb), the nucleus tractus solitarius (NTS), and the pre-Bötzinger complex (pre-BötC) were investigated by Nissl staining; the malondialdehyde (MDA) content and superoxide dismutase (SOD) activity were measured to evaluate the anti-oxidant effect; some apoptosis parameters, Bax mRNA and Bcl-2 mRNA, were tested; and the double immunochemistry staining of active caspase-3/NeuN was performed. Meanwhile, the HO-1 protein expression and heme oxygenase (HO) activity were examined. Tin-protoporphyrin (SnPP), a potent inhibitor of HO, was used to further confirm the effect of HO-1. We found that TMP ameliorated the neuron loss in 12N, Amb and NTS, the decrease in SOD activity and the increase in MDA content, the decrease in Bcl-2 mRNA of medulla oblongata ( P < 0.05), and the increase in percentage of apoptotic neurons in Amb ( P < 0.05) induced by chronic hypoxia. Co-administration with SnPP abolished the beneficial effects above of TMP to some extent ( P < 0.05). Moreover, TMP significantly increased HO activity and HO-1 protein expression, which was most likely enhanced in the neurons ( P < 0.05), and co-administration of SnPP reduced these up-regulated effects ( P < 0.05). This study demonstrated that HO-1 dependant pathway may be involved in the protective action of TMP against chronic hypoxic damage on medulla oblongata in the rats. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
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