Microbial transformation of glabratephrin, the major isolated compound from Tephrosia purpurea, afforded pseudosemiglabrin. The formation of the transformed compound seems to be performed via ring opening-closure of a five-membered ring causing transformation from a spiro into a fused system. The structure of the transformed compound was determined by comprehensive NMR studies, including DEPT, ...

in this note we introduce the notion of weak mccoy rings as a generalization of mccoy rings, and investigate their properties. also we show that, if is a semi-commutative ring, then is weak mccoy if and only if is weak mccoy.

In this work, we present a generic framework for constructing efficient signature schemes, ring signature schemes, and identity based encryption schemes, all in the standard model (without relying on random oracles). We start by abstracting the recent work of Hohenberger and Waters (Crypto 2009), and specifically their “prefix method”. We show a transformation taking a signature scheme with a v...

The Ring-LWE problem, introduced by Lyubashevsky, Peikert, and Regev (Eurocrypt 2010), has been steadily finding many uses in numerous cryptographic applications. Still, the Ring-LWE problem defined in [LPR10] involves the fractional ideal R∨, the dual of the ring R, which is the source of many theoretical and implementation technicalities. Until now, getting rid of R∨, required some relatively...

A. S. Shawali, M. A . A bdallah , and M. E. M. Z ay ed Department of Chemistry, Faculty of Science, University of Cairo, Giza, Egypt Reprint requests to Dr. A. S. Shawali. E-mail: [email protected] Z. Naturforsch. 55b, 546-552 (2000); received February 4. 2000 Ring-Chain Tautomerism. Heterocyclic Ring Transformation, 1,3,4-Thiadiazoles The synthesis and antimicrobial activity of a s...

Let A be a ring with identity. The generalized affine transformation monoid Gaff(A) is defined as the set of all transformations on A of the form x → xu + a (for all x ∈ A), where u,a∈ A. We study the algebraic structure of the monoid Gaff(A) on a finite Galois ring A. The following results are obtained: an explicit description of Green’s relations on Gaff(A); and an explicit description of the...