Search

Sirolimus (SRL)-based immunosuppressive regimens have been used for preventing rejection after kidney transplantation. This review analyzes their merits and demerits compared with other conventional regimes from the aspects of acute rejection rate, graft function, as well as patient/graft survival rates. In general, SRL is mostly recommended to be used as conversion therapy from calcineurin inhibitor (CNI) after kidney transplantation in most studies. Minimization or withdrawal of cyclosporine A (CsA) could also be considered when it was combined with SRL. SRL can replace mycophenolate mofetil (MMF), and the CNI dose should be reduced appropriately in this setting. Quadruple maintenance regimens containing SRL need future study to clarify their superiority. De novo use of low-dose CNI combined with SRL has no apparent merits and thus is not recommended. De novo use of standard-dose CNI combined with SRL followed by maintenance, de novo use of CNI-free regimens, as well as SRL use in delayed graft function (DGF) patients who spare antibody induction and postpone CNI administration should also be avoided. SRL supports steroids withdrawal after kidney transplantation, and SRL combined with tacrolimus is recommended in this setting. Loading dose is recommended when initiating SRL treatment and its trough blood level should be routinely monitored. [ABSTRACT FROM AUTHOR]

The nucleation of Cr precipitates induced by overlapping of displacement cascades in Fe–Cr alloys has been investigated using the combination of molecular dynamics (MD) and Metropolis Monte Carlo (MMC) simulations. The results reveal that the number of Frenkel pairs increases with the increasing of overlapped cascades. Overlapping cascades could promote the formation of Cr precipitates in Fe–Cr alloys, as analyzed using short range order (SRO) parameters to quantify the degree of ordering and clustering of Cr atoms. In addition, the simulations using MMC approach show that the presence of small Cr clusters and vacancy clusters formed within cascade overlapped region enhance the nucleation of Cr precipitates, leading to the formation of large Cr dilute precipitates. [ABSTRACT FROM AUTHOR]

Abstract: A new Al–18Si–2.5P master alloy has been successfully prepared to refine primary Si in hypereutectic A390 alloys, and the relationship between the microstructure and refining performance was investigated. The results show that as the solidification rate increases, the size of AlP particles in Al–18Si–2.5P master alloy reduces and the morphology of AlP evolves from plate-like to the fine nodular shape. The rapid solidification has a significant improvement on the refining performance and the P recovery of Al–18Si–2.5P master alloy. It is suggested that the difference in refining performance of Al–18Si–2.5P master alloy is related to the morphology, size and quantity of AlP particles in master alloy, which could influence the dissolution rate of AlP and thereby affect the refining performance. [Copyright &y& Elsevier]

Abstract: In this paper, the mixing characteristics of the dry and wet particles in a rectangular spouted bed are simulated using a three-dimensional discrete element method (DEM). In particular, the influence of turbulence and liquid bridge force is investigated using the standard k-ε two-equation model and the Mikami model. The Ashton mixing index is adopted to evaluate the dynamic mixing process of the particle system. The geometry of the simulated bed is the same as that of the experimental bed by Liu et al. [G. Q. Liu, S. Q. Li, X. L. Zhao, Q. Yao. Chem. Eng. Sci. 63 (2008) 1131–1141]. The effect of the spouting gas velocity on the mixing process is discussed for the mixing of dry particles (without the liquid bridge force), while the effect of the moisture content is discussed for the mixing of wet particles (with the liquid bridge force). [Copyright &y& Elsevier]