Investigation of the compressible flow through the tip-section turbine blade cascade with supersonic inlet

The contribution deals with the experimental and numerical investigation of compressible flow through the tip-section turbine blade cascade with the blade 54″ long. Experimental investigations by means of optical(interferometry and schlieren method) and pneumatic measurements provide more information about the behaviour and nature of basic phenomena occurring in the profile cascade flow field. The numerical simulation was carried out by means of the EARSM turbulence model according to Hellsten [5] completed by the bypass transition model with the algebraic equation for the intermittency coefficient proposed by Straka and P?íhoda [6] and implemented into the in-house numerical code. The investigation was focused particularly on the effect of shock waves on the shear layer development including the laminar/turbulent transition. Interactions of shock waves with shear layers on both sides of the blade result usually in the transition in attached and/ or separated flow and so to the considerable impact to the flow structure and energy losses in the blade cascade.     

c-Ras is required for the activation of the matrix metalloproteinases by concanavalin A in 3Y1 cells

Concanavalin A (Con A) is known to trigger augmented secretion and proteolytic activation of the matrix metalloproteinases (MMPs) in fibroblasts. To study the signaling pathway critical for the activation of MMPs in fibroblasts, we examined the effects of dominant negative ras (S17N ras) expression under the control of conditionally inducible promoter in Con A-activated 3Y1 cells. We found that augmented secretion and proteolytic activation of MMP-2 and MMP-9 together with expression of MT1-MMP in Con A-activated 3Y1 were dramatically suppressed by S17N ras expression. These results strongly suggest that c-Ras plays a critical role in the augmented expression and proteolytic activation of MMPs in fibroblasts.     

Palladium as a substrate for self-assembled monolayers used in biotechnology

This paper describes self-assembled monolayers (SAMs) on palladium that resist the nonspecific adsorption of proteins and the adhesion of mammalian cells. These SAMs form when thin films of palladium are exposed to solutions of alkanethiol with the general structure HS(CH(2))(m)()(OCH(2)CH(2))(n)()OH (m = 2, 11; n = 3, 6, 7). Ellipsometry and surface plasmon resonance spectroscopy (using a palladium-on-gold substrate) showed that these SAMs resist adsorption of all proteins present in bovine serum. Microislands of SAMs of octadecanethiol on palladium allowed patterned adhesion and growth of mammalian cells (in a "sea" of oligo(ethyleneglycol)-terminated SAM). The oligo(ethyleneglycol)-terminated SAM resisted the invasion of cells for over four weeks under standard conditions of cell culture; similar SAMs on gold remained patterned for only two weeks.     

Cryogenic fracture toughness of 9Ni Steel enhanced through grain refinement

A thermal cycling technique was used to refine the grain size of commercial ld9Ni≓ cryogenic steel. The grain refined alloy was then tempered, a treatment which introduced a small admixture of retained austenite. The reprocessed alloy shows an excellent combination of strength and toughness to temperatures as low as 6 K, and shows little evidence of embrittlement in liquid helium. The microstructure and mechanical properties of the reprocessed alloy are described and compared to those obtained through conventional treatment. Formerly an Assistant Research Engineer, Department of Materials Science and Engineering, University of California, Berkeley