Programmed cell death ligand 1 (PD-L1), one of the key inhibitory immune checkpoint ligand, is often overexpressed on the surface of tumor cells, such as melanoma, ovarian and lung cancers. Its receptor programmed cell death 1 (PD-1) is expressed on the surface of activated T cells. Interaction between PD-L1 and PD-1 transmits negative regulatory signals to T cells. Then it suppresses T-cell activity, promotes apoptosis, and lead to exhaustion of T cells. As a result, the PD-L1/PD-1 interaction allows tumors to be avoided from immune recognition and T cell attack.
Fatigue life prediction of solder joints is one of the most important areas of research in the development of reliable electronic packages. Recent trends in electronic package development indicate a shift toward smaller solder joints and larger package sizes, and temperature changes under field conditions are also becoming greater. Since reliability design of solder joints has become severer, the estimation of the crack propagation is becoming important like the estimation of the crack initiation. In the present study, a new method of estimating the crack propagation, which is based on finite element analysis without geometrical crack model, was examined, in order to ensure suitability for practical use in electronic package design. On the basis of a damage model assumed for Sn-37Pb solder, the new method called ‘damage path simulation’ was verified for solder joints in QFP (Quad Flat Package). In the case of solder joints of the gull-wing type, fatigue cracks are commonly initiated from the upper surface of the solder fillet, and propagated in the vicinity of the interface with the outer lead. It was clear that the extension of the damage path showed good agreement with the behavior of crack propagation observed in the actual thermal cycle tests. Damage path extension from a pointed end of outer lead is also simulated simultaneously with that from the upper surface of the solder fillet, and both damage paths were finally combined at a gap between outer lead and printed circuit board. The advantage of the present method is especially evident when the fatigue cracks were initiated from two or more regions. From the results of this study, it was concluded that the estimation of the crack propagation in solder joints based on the present method is satisfactory for engineering purposes.
A water-lubricated bearing has the following characteristics : (1) turbulent flow, (2) full film due to high ambient pressure, and (3) large additional mass effect. These characteristics have not yet been fully solved. In this paper, the results are presented on cylindrical bearing characteristics, which are numerically analysed and tested using special test system.
Through holes which were for electric signal communication were formed in printed circuit board. The surface of through hole was plated by thin metal and the irregularities were shaped on the free surface or on the interface due to hole-drilling process for making through holes in circuit board. Fracture of through hole was occurred by stress concentration due to its irregularity. In this study, inelastic thermal stress simulation was performed by using a large scale simulator ADVENTURECluster which was based on FEM to discuss fatigue strength around through hole of a printed circuit board.
ABSTRACT Interleukin-6 (IL-6) binds to the IL-6 receptor (IL-6R) subunit, related to autoimmune diseases and cytokine storm in COVID-19. In this study, we performed systematic evolution of ligands by exponential enrichment and identified a novel RNA aptamer. This RNA aptamer not only bound to IL-6R with a dissociation constant of 200 n m, but also inhibited the interaction of IL-6R with IL-6.
