RESUMO
Backward-angle meson electroproduction above the resonance region, which was previously ignored, is anticipated to offer unique access to the three quark plus sea component of the nucleon wave function. In this Letter, we present the first complete separation of the four electromagnetic structure functions above the resonance region in exclusive ω electroproduction off the proton, epâe^{'}pω, at central Q^{2} values of 1.60, 2.45 GeV^{2}, at W=2.21 GeV. The results of our pioneering -u≈-u_{min} study demonstrate the existence of a unanticipated backward-angle cross section peak and the feasibility of full L/T/LT/TT separations in this never explored kinematic territory. At Q^{2}=2.45 GeV^{2}, the observed dominance of σ_{T} over σ_{L}, is qualitatively consistent with the collinear QCD description in the near-backward regime, in which the scattering amplitude factorizes into a hard subprocess amplitude and baryon to meson transition distribution amplitudes: universal nonperturbative objects only accessible through backward-angle kinematics.
RESUMO
We investigated factors such as time span between transplantation and having offspring, the dosage of immunosuppressive agents during fertilisation and the effects of fertilisation on recipient's renal allograft function in 212 male recipients registered at eight Chinese organ transplantation centres. Our results are as follows: the 212 male renal allograft recipients conceived with their wives between 15 and 204 months after transplantation. The wives who became pregnant at 15-24 months after the renal transplantation gave birth to a total of 20 babies with an average weight of 3115 ± 517 g, of which 3 (15.0%) were premature. The wives who became pregnant at 25-204 months after the renal transplantation gave birth to a total of 196 babies with an average weight of 3384 ± 438 g, of which 6 (3.1%) were premature. All recipients had normal renal function during the fertile period. In conclusion, the fertility capacity of male renal allograft recipients was associated with the time after transplantation and the dose of immunosuppressive agents used during fertilisation. It might be helpful to have a fertility capacity evaluation before fertilisation. There were no effects of fertility on renal allograft function.
Assuntos
Fertilidade , Imunossupressores/administração & dosagem , Transplante de Rim , Adulto , Peso ao Nascer , Ciclosporina/administração & dosagem , Feminino , Fertilidade/efeitos dos fármacos , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Masculino , Pessoa de Meia-Idade , Gravidez , Análise do SêmenRESUMO
The therapeutic value of the transforming growth factor beta 1 (TGF-beta1) in transplantation has been reported; however, cell-mediated gene therapy using TGF-beta1 is not a widespread application in organ transplantation. This study was performed to evaluate whether TGF-beta1-modified donor spleen cell-specific transfusion could induce tolerogenicity and prolong allograft survival in rat heterotopic heart transplantation. Stable TGF-beta1-transduced spleen cells were established. Wistar rat splenic T-cell responses to donor spleen cells that received TGF-beta1-transduced were severely impaired. Survival of Sprague-Dawley cardiac allografts in Wistar rats given TGF-beta1-modified donor spleen cells (5 x 10(6), 7 days before transplantation), was extended modestly but significantly. Liposome transduction of donor spleen cells to overexpress TGF-beta1 is associated with marked impairment of their T-cell allostimulatory activity but only modest prolongation of allo-heart survival.
Assuntos
Sobrevivência de Enxerto/fisiologia , Transplante de Coração/imunologia , Fator de Crescimento Transformador beta/genética , Fator de Crescimento Transformador beta/imunologia , Animais , Técnicas de Transferência de Genes , Substâncias de Crescimento/genética , Transplante de Coração/patologia , Tolerância Imunológica , Ativação Linfocitária , Teste de Cultura Mista de Linfócitos , Transfusão de Linfócitos , Modelos Animais , Ratos , Ratos Endogâmicos WF , Ratos Sprague-Dawley , Baço/citologia , Baço/imunologia , Linfócitos T/imunologia , Fator de Crescimento Transformador beta1 , Transplante HeterólogoRESUMO
The 1H(e,e'pi+)n cross section was measured at four-momentum transfers of Q2=1.60 and 2.45 GeV2 at an invariant mass of the photon nucleon system of W=2.22 GeV. The charged pion form factor (F(pi)) was extracted from the data by comparing the separated longitudinal pion electroproduction cross section to a Regge model prediction in which F(pi) is a free parameter. The results indicate that the pion form factor deviates from the charge-radius constrained monopole form at these values of Q2 by one sigma, but is still far from its perturbative quantum chromodynamics prediction.
RESUMO
Separated longitudinal and transverse structure functions for the reaction 1H(e,e(')pi(+))n were measured in the momentum transfer region Q2 = 0.6--1.6 (GeV/c)(2) at a value of the invariant mass W = 1.95 GeV. New values for the pion charge form factor were extracted from the longitudinal cross section by using a recently developed Regge model. The results indicate that the pion form factor in this region is larger than previously assumed and is consistent with a monopole parametrization fitted to very low Q2 elastic data.