| 1. |
- Ma, Yunhan, et al.
(författare)
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Leflunomide Inhibits rat-to-Mouse Cardiac Xenograft Rejection by Suppressing Adaptive Immune Cell Response and NF-κB Signaling Activation
- 2021
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Ingår i: Cell Transplantation. - : SAGE Publications. - 0963-6897 .- 1555-3892. ; 30
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Tidskriftsartikel (refereegranskat)abstract
- Xenotransplantation is a potential solution for the severe shortage of human donor organs and tissues. The generation of humanized animal models attenuates strong innate immune responses, such as complement-mediated hyperacute rejection. However, acute vascular rejection and cell mediated rejection remain primary barriers to xenotransplantation, which limits its clinical application. In this study, we systematically investigated the immunosuppressive effect of LEF using a rat-to-mouse heart xenotransplantation model. SD rat xenogeneic hearts were transplanted into C57BL/6 mice, and survived 34.5 days after LEF treatment. In contrast, BALB/c allogeneic hearts were transplanted into C57BL/6 mice, and survived 31 days after LEF treatment. Compared to normal saline treatment, LEF treatment decreased xenoreactive T cells and CD19+ B cells in recipient splenocytes. Most importantly, LEF treatment protected myocardial cells by decreasing xenoreactive T and B cell infiltration, inflammatory gene expression, and IgM deposition in grafts. In vivo assays revealed that LEF treatment eliminated xenoreactive and alloreactive T and B lymphocytes by suppressing the activation of the NF-κB signaling pathway. Taken together, these observations complement the evidence supporting the potential use of LEF in xenotransplantation.
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| 2. |
- Sterneland, Therese, et al.
(författare)
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Solubility of Co in Cr7c3-Ab initio studies and experimental verification
- 2006
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Ingår i: Scripta Materialia. - : Elsevier BV. - 1359-6462 .- 1872-8456. ; 54:8, s. 1491-1495
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Tidskriftsartikel (refereegranskat)abstract
- Experimental determination of the cobalt solubility in the three-phase triangle face-centered cubic + Cr7C3 + graphite have been carried out. In the present work these results are compared with atomistic calculations of the solubility of Co in Cr7C3 phase based on ab initio cohesive energies and lattice inversion method. Comparisons are also made with the literature data reported earlier [Koster W, Sperner F. Arch Eisenhuttenwesen 1955;26:555; Thompson ER, Lemkey FD, Metall Trans 1970-1:2799; Sabin PR, Watts DJ. Metall Trans 1971;2:1260; Sahm PR, Lorenz M, Hugi W, Fruhauf V. Mettal Trans 19723:1022; Tuma H, Lobl K. Kovove Mater 1971;9:221; Fritscher K. Thermochim Acta 1979;29:357].
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| 3. |
- Xie, Jiaying, 1975-
(författare)
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Atomistic simulation and experimental studies of transition metal systems involving carbon and nitrogen
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The present work was initiated to investigate the stability, structural and thermodynamic properties of transition metal carbides, nitrides and carbo-nitrides by atomistic simulations and experimentations. The interatomic pair potentials of Cr-Cr, Mn-Mn, Fe-Fe, C-C, Cr-C, Mn-C, Fe-C, Cr-Fe, Cr-N and Mn-N were inverted by the lattice inversion method and ab initio cohesive energies, and then employed to investigate the properties of Cr-, Mn- and Fe-carbides by atomistic simulations in this work. For the binary M7C3 carbide, the structural properties of M7C3 (M = Cr, Mn, Fe) were investigated by atomistic simulations. The results show that the stable structure for these compounds is hexagonal structure with P63mc space group. The cohesive energy of M7C3 calculated in this work indicates that the stability of carbides decreases with the increasing in metal atomic number. Further, the vibrational entropy of Cr7C3 was calculated at different temperatures and compared with the entropy obtained by experimentations. The comparison demonstrates that the main contribution to the entropy is made by the vibrational entropy. For the binary τ-carbides, the structural properties of Cr23C6 and Mn23C6, as well as the vibrational entropy of Cr23C6 were computed. Further, the site preference of ternary element Fe among 4a, 8c, 32f and 48h symmetry sites in Cr23-xFexC6 was studied. It has been seen that Fe atoms would firstly occupy 4a sites and then 8c sites. The lattice constant and stability of Cr23-xFexC6 were also computed with different Fe content. In order to understand the relative stability of the transition metal carbides and nitrides, the standard formation Gibbs energies of carbides and nitrides for Cr, Mn and Fe were compared. The order of carbon and nitrogen affinities for Cr, Mn and Fe was further clarified by the comparison of the interatomic pair potentials among Cr-C, Mn-C, Fe-C, Cr-N and Mn-N. It was found that Cr-N interaction was very strong in comparison with other binary interactions above and consequently, nitrogen addition would lead to a strong decrease in the thermodynamic activity of chromium in Cr-containing alloys. This was confirmed by the investigations of thermodynamic activities of Cr in the Fe-Cr-N and Fe-Cr-C-N alloys. The activities were measured in the temperature range 973-1173 K by solid-state galvanic cell method involving CaF2 solid electrolyte under the purified N2 gas. In addition, the analysis of nitrogen content and phase relationships in the Fe-Cr-N and Fe-Cr-C-N alloys equilibrated at 1173 K were carried out by inert-gas fusion thermal conductivity method, X-ray diffraction and scanning electron microscopy technique. The experimental results show that the solubility of nitrogen in the alloys decreases with the decreasing chromium content, as well as the increasing temperature. The addition of nitrogen to the alloys was found to have a strong negative impact on the Cr activity in Fe-Cr-N and Fe-Cr-C-N systems.
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| 4. |
- Xie, Jiaying, et al.
(författare)
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Atomistic simulation on the structural properties and phase stability for Cr23C6 and Mn23C6
- 2006
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 420:1-2, s. 269-272
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Tidskriftsartikel (refereegranskat)abstract
- Based on the successful applications of lattice inversion method in many fields, the crystal structure and phase stability of Cr23C6 and Mn23C6 are investigated using the interatomic potentials obtained by lattice inversion method in this research. The calculated atomic coordinates and crystal parameters are in good agreement with the experimental results and the phase stability of Cr23C6 and Mn23C6 are tested by random atom shifts and global deformations. The calculated energy also indicates that the Cr23C6 is more stable than Mn23C6.
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| 5. |
- Xie, Jiaying, et al.
(författare)
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Atomistic study on the site preference and thermodynamic properties for Cr23-xFexC6
- 2005
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Ingår i: Acta Materialia. - : Elsevier BV. - 1359-6454 .- 1873-2453. ; 53:20, s. 5305-5312
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Tidskriftsartikel (refereegranskat)abstract
- The site preference of Fe in Cr23-xFexC6 is investigated based on the interatomic potentials obtained by the lattice inversion method. The calculated results show that Fe atoms preferentially Substitute For Cr at 4a sites first and then 8c sites. The structural parameters of Cr23-xFexC6 With content x are calculated and the results are consistent with experimental results. The calculated cohesive energies indicate that the increase in x value is accompanied by the decrease in the stability of Cr23-xFexC6. The thermodynamic properties of Cr23C6, such as the phonon density of states and vibrational entropy, as well as the bulk modulus of Cr23-xFexC6 are evaluated. The calculated results are in good agreement with experimental results. This work provides a simple and promising method for Studying the properties of carbides with complex structures
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| 6. |
- Xie, Jiaying, et al.
(författare)
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Atomistic study on the structure and thermodynamic properties of Cr7C3, Mn7C3, Fe7C3
- 2005
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Ingår i: Acta Materialia. - : Elsevier BV. - 1359-6454 .- 1873-2453. ; 53:9, s. 2727-2732
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Tidskriftsartikel (refereegranskat)abstract
- The crystal structures and stabilities of Cr7C3, Mn7C3, Fe7C3 have been investigated using the interatomic potentials obtained by the lattice inversion method. The calculated structures of Cr7C3, Mn7C3 and Fe7C3 are proposed to be hexagonal with P6(3)mc space group and the calculated lattice constants are in basic agreement with the experimental data. The calculated cohesive energies indicate that the increase in the atomic number of the metal is accompanied by the decrease in the stability of its carbides. The phonon density of states and vibrational entropy related to dynamic phenomena are also evaluated. This work provides a new method for studying the properties of carbides with complex structure.
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| 7. |
- Xie, Jiaying, et al.
(författare)
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Site preference and mechanical properties of Cr23-xTxC6 and Fe21T2C6 (T = Mo, W)
- 2006
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Ingår i: Acta Materialia. - : Elsevier BV. - 1359-6454 .- 1873-2453. ; 54:18, s. 4653-4658
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Tidskriftsartikel (refereegranskat)abstract
- The site preference, stability, crystal structure and mechanical properties of Cr23-xTxC6 and Fe21T2C6 (T = Mo, W) carbides have been investigated using inverted pair potentials. Among the four different kinds of metal sites in these compounds, the most preferential sites for Mo atoms or W atoms are 8c sites. The result of stability indicates that each of the Mo atoms and W atoms significantly increases the stability of Cr23C6 and Fe23C6. The stability of Fe21T2C6 is lower than that of Cr21T2C6 and the carbides containing W atoms are more stable than those containing Mo atoms. The calculated structural properties are in good agreement with experimental data. Further-more, the mechanical properties have also been evaluated and the results indicate that Mo atoms or W atoms can improve the hardenability of the systems.
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| 8. |
- Xie, Jiaying, et al.
(författare)
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STING activation in TET2-mutated hematopoietic stem/progenitor cells contributes to the increased self-renewal and neoplastic transformation
- 2023
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Ingår i: Leukemia. - : Springer Nature. - 0887-6924 .- 1476-5551. ; 37:12, s. 2457-2467
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Tidskriftsartikel (refereegranskat)abstract
- Somatic loss-of-function mutations of the dioxygenase Ten-eleven translocation-2 (TET2) occur frequently in individuals with clonal hematopoiesis (CH) and acute myeloid leukemia (AML). These common hematopoietic disorders can be recapitulated in mouse models. However, the underlying mechanisms by which the deficiency in TET2 promotes these disorders remain unclear. Here we show that the cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS)-stimulator of interferon genes (STING) pathway is activated to mediate the effect of TET2 deficiency in dysregulated hematopoiesis in mouse models. DNA damage arising in Tet2-deficient hematopoietic stem/progenitor cells (HSPCs) leads to activation of the cGAS-STING pathway which in turn promotes the enhanced self-renewal and development of CH. Notably, both pharmacological inhibition and genetic deletion of STING suppresses Tet2 mutation-induced aberrant hematopoiesis. In patient-derived xenograft (PDX) models, STING inhibition specifically attenuates the proliferation of leukemia cells from TET2-mutated individuals. These observations suggest that the development of CH associated with TET2 mutations is powered through chronic inflammation dependent on the activated cGAS-STING pathway and that STING may represent a potential target for intervention of relevant hematopoietic diseases.
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| 9. |
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| 10. |
- Xie, Jiaying, et al.
(författare)
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Thermodynamic studies of the Fe-Cr-C-N system by EMF measurements
- 2007
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Ingår i: Metallurgical and materials transactions. B, process metallurgy and materials processing science. - : Springer Science and Business Media LLC. - 1073-5615 .- 1543-1916. ; 38:1, s. 93-100
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Tidskriftsartikel (refereegranskat)abstract
- In this work, the Fe-Cr-C-N alloys were synthesized by nitriding the Fe, Cr, and C powder mixtures at 1573 K in the N-2 gas (101 325 Pa). The nitrogen content and phase relationships at 1173 K in the alloys were investigated by the use of an equilibration technique. The thermodynamic activities of chromium in the alloys were studied using the solid-state galvanic cell method with CaF2 as the solid electrolyte in the temperature range 973 to 1173 K in an atmosphere of N-2 gas (101 325 Pa). The activities of chromium in the Fe-Cr-C-N alloys were calculated and compared with those of the corresponding Fe-Cr-C ternary alloys with pure bcc-Cr as standard state. X-ray diffraction (XRD) and scanning electron microscopy (SEM) methods were used to identify the equilibrium phases and microstructures of the investigated alloys. The experimental results show that a Cr2N-based nitride was formed during the nitriding procedure in the alloys. The nitrogen content in the alloys decreases with the decreasing chromium content, as well as the increasing temperature. The addition of nitrogen to the ternary Fe-Cr-C alloy was found to have a strong negative impact on the Cr activity in the Fe-Cr-C-N system.
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