Objective ： To investigate the mechanism of phenotypic knockout of CXCR4 on T-cell leukemia cell line Molt-4 via SDF-1α/54/KDEL intrakine technology, which the mutant SDF-1α/54, human stromal cell-derived Faceor-1 ...Objective ： To investigate the mechanism of phenotypic knockout of CXCR4 on T-cell leukemia cell line Molt-4 via SDF-1α/54/KDEL intrakine technology, which the mutant SDF-1α/54, human stromal cell-derived Faceor-1 （SDF-1α） was deleted its C- terminal α-helix and attached with a endoplasimc reticulum retention signal 4-peptide- KDEL encoding gene, so that retain the newly synthesized receptor CXCR4 within the Molt-4 cells endoplasmic reticulum. Methods： The recombinant vector pEGFP-C3/SDF- 1α/54/KDEL were transfected into Cos-7 cells by liposome, SDF-1α/54/KDEL fusion protein was confirmed with western blot. The recombinant plasmids were transfected transiently into Molt-4 by electroporation. Results：Western blot confirmed SDF-1α/54/KDEL expression in Cos-7. A dramatic downregulation of CXCR4 expression on Molt-4 was demonstrated by flow cytometric （FCM） analysis. Conelusion：SDF-1α/54/KDEL and SDF- 1αKDEL have no significant deviation for phenotypic knockout of CXCR4. These suggest that the phenotypic knockout effects of SDF-1α/54 against CXCR4 are not influenced by deleting of SDF-1α helix in the C-terminal.展开更多
In this paper some new results for general orthogonal polynomials on infinite intervals are presented. In particular, an answer to Problem 54 of P. Turan[J. Approximation Theory, 29(1980),P.64] is given.
Fatigue and tensile behaviors of homogenized WE 54 magnesium alloy before and after immersion in simulated body fluid(SBF)were investigated.According to the tensile test,the alloy without immersion in SBF solution has...Fatigue and tensile behaviors of homogenized WE 54 magnesium alloy before and after immersion in simulated body fluid(SBF)were investigated.According to the tensile test,the alloy without immersion in SBF solution has the highest tensile strength of 278 MPa,which decreased to 190 MPa after 336 h of immersion..The fatigue life of the homogenized WE 54 magnesium alloy before immersion in the SBF solution under a constant stress of 15 MPa is 3598 cycles.However,the fatigue life of the alloy decreased to 453 cycles after 336 h of immersion in the SBF solution under the same stress.Examination of the fracture surface of the samples by SEM reveals that the origin of the fatigue crack before immersion is micro-pores and defects.While corrosion pits and cracks are the main reasons for forming the initial fatigue crack after immersion.Moreover,the results obtained from practical work were evaluated and compared to theoretical calculations.The area of the hysteresis loops of the samples after the fatigue test,determined using Triangles and Monte Carlo methods,decreased from 4954.5 MPa and 4842.9 MPa before immersion to 192.0 MPa and 175.8 MPa after 336 h of immersion,respectively.展开更多
基金Grant sponsor:National Natural Science Foundation of ChinaGrant number:30572209
文摘Objective ： To investigate the mechanism of phenotypic knockout of CXCR4 on T-cell leukemia cell line Molt-4 via SDF-1α/54/KDEL intrakine technology, which the mutant SDF-1α/54, human stromal cell-derived Faceor-1 （SDF-1α） was deleted its C- terminal α-helix and attached with a endoplasimc reticulum retention signal 4-peptide- KDEL encoding gene, so that retain the newly synthesized receptor CXCR4 within the Molt-4 cells endoplasmic reticulum. Methods： The recombinant vector pEGFP-C3/SDF- 1α/54/KDEL were transfected into Cos-7 cells by liposome, SDF-1α/54/KDEL fusion protein was confirmed with western blot. The recombinant plasmids were transfected transiently into Molt-4 by electroporation. Results：Western blot confirmed SDF-1α/54/KDEL expression in Cos-7. A dramatic downregulation of CXCR4 expression on Molt-4 was demonstrated by flow cytometric （FCM） analysis. Conelusion：SDF-1α/54/KDEL and SDF- 1αKDEL have no significant deviation for phenotypic knockout of CXCR4. These suggest that the phenotypic knockout effects of SDF-1α/54 against CXCR4 are not influenced by deleting of SDF-1α helix in the C-terminal.
基金The Project Supported by National Natural Science Foundation of China
文摘In this paper some new results for general orthogonal polynomials on infinite intervals are presented. In particular, an answer to Problem 54 of P. Turan[J. Approximation Theory, 29(1980),P.64] is given.
文摘Fatigue and tensile behaviors of homogenized WE 54 magnesium alloy before and after immersion in simulated body fluid(SBF)were investigated.According to the tensile test,the alloy without immersion in SBF solution has the highest tensile strength of 278 MPa,which decreased to 190 MPa after 336 h of immersion..The fatigue life of the homogenized WE 54 magnesium alloy before immersion in the SBF solution under a constant stress of 15 MPa is 3598 cycles.However,the fatigue life of the alloy decreased to 453 cycles after 336 h of immersion in the SBF solution under the same stress.Examination of the fracture surface of the samples by SEM reveals that the origin of the fatigue crack before immersion is micro-pores and defects.While corrosion pits and cracks are the main reasons for forming the initial fatigue crack after immersion.Moreover,the results obtained from practical work were evaluated and compared to theoretical calculations.The area of the hysteresis loops of the samples after the fatigue test,determined using Triangles and Monte Carlo methods,decreased from 4954.5 MPa and 4842.9 MPa before immersion to 192.0 MPa and 175.8 MPa after 336 h of immersion,respectively.
