SUMMARYThe FETI method and its two-level extension (FETI-2) are two numerically scalable domain decomposition methods with Lagrange multipliers for the iterative solution of second-order solid mechanics and fourth-order beam, plate and shell structural problems, respectively.The FETI-2 method distinguishes itself from the basic or one-level FETI method by a second set of Lagrange multipliers that are introduced at the subdomain cross-points to enforce at each iteration the exact continuity of a subset of the displacement ÿeld at these speciÿc locations. In this paper, we present a dual-primal formulation of the FETI-2 concept that eliminates the need for that second set of Lagrange multipliers, and uniÿes all previously developed one-level and two-level FETI algorithms into a single dual-primal FETI-DP method. We show that this new FETI-DP method is numerically scalable for both second-order and fourth-order problems. We also show that it is more robust and more computationally e cient than existing FETI solvers, particularly when the number of subdomains and=or processors is very large. Copyright ? 2001 John Wiley & Sons, Ltd.KEY WORDS: domain decomposition; numerical scalability; iterative methods BACKGROUNDThe ÿnite element tearing and interconnecting (FETI) methods are a family of domain decomposition (DD) algorithms with Lagrange multipliers that have been developed during the last decade for the fast sequential and parallel iterative solution of large-scale systems of equations arising from the ÿnite element discretization of partial di erential equations. From a mechanical viewpoint, a FETI method can be viewed as an iterative substructuring method where Lagrange multipliers are introduced at the substructure interfaces to enforce the continuity of the displacement ÿeld. By

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Structure‐activity relationships of homopiperazine‐containing alkoxybiaryl nitriles employing various D‐amino acid moieties and their N‐furanoyl analogues were undertaken. This led to A‐320436, a potent and selective non‐imidazole H3‐receptor antagonist possessing balanced affinity for both rat and human H3‐receptors. This compound was shown to demonstrate in vitro and in vivo functional antagonism and is non‐neurotoxic at doses (i.p.) up to 163 mg/kg in a general observation test.

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