for a fixed positive integer , we say a ring with identity is n-generalized right principally quasi-baer, if for any principal right ideal of , the right annihilator of is generated by an idempotent. this class of rings includes the right principally quasi-baer rings and hence all prime rings. a certain n-generalized principally quasi-baer subring of the matrix ring are studied, and connections...

The 3.0-3.1A X-ray structures of the cytochrome b(6)f complex from Mastigocladus laminosus and Chlamydomonas reinhardtii obtained in the presence of the p-side quinone-analogue inhibitor tridecyl-stigmatellin (TDS) are very similar. A difference occurs in the p-side binding position of TDS. In C.reinhardtii, TDS binds in the ring-in mode, as previously found for stigmatellin in X-ray structures...

In this paper we introduce some key exchange protocols over noncommutative rings. These protocols use some polynomials with coefficients in the center of the ring as part of the private keys. We give some examples over the ring End(Zp × Zp2), where p is a prime number. We also give a security analysis of the proposed protocols and conclude that the only possible attack is by brute force.

A regio- and stereoselective method has been developed for the synthesis of novel fluorinated 2-aminocyclohexanecarboxylic acid derivatives with the fluorine attached to position 4 of the ring. The synthesis starts from either cis- or trans-β-aminocyclohex-4-enecarboxylic acids and involves regio- and stereoselective transformation of the ring C-C double bond through iodooxazine formation and h...

The 220 MHz spectra of tocinamide and deaminotocinamide, the ring moieties of oxytocin and of deamino-oxytocin, respectively, were investigated in [U-(2)H]dimethylsulfoxide solution. Extensive decoupling and exchange experiments allow complete spectral assignment and determination of many coupling constants. Circular dichroism spectra assigned a right-hand screw sense to the C-S-S-C group. The ...

The macrocyclic hexanuclear manganese(III) 18-metallacrown-6, [Mn6(pmshz)6(DMF)4(C2H5OH)2]·4DMF (1), where pmshz3− is N-propionyl-N′-5-methylsalicylhydrazide, has been synthesized by self-assembly and structurally characterized. The ring is formed by the succession of six structural moieties of the type [Mn(III)-N-N] with hydrazide N-N groups bridging the ring Mn ions. The ligand enforces the m...

For the title compound, C(13)H(14)ClNO(3)S, geometrical parameters, determined using X-ray diffraction techniques, are compared with those calculated by density functional theory (DFT), using hybrid exchange-correlation functional, B3LYP methods. The dihedral angle between the benzene ring and the conjugated part of the cyclo-hexene ring is 87.47 (5)°. The cyclo-hexene ring and its substituents...

The family of algebraic graphs A(n;K) defined over the finite commutative ring K were used for the design of different multivariate cryptographical algorithms (private and public keys, key exchange protocols). The encryption map corresponds to a special walk on this graph. We expand the class of encryption maps via the use of an automorphism group of A(n,K). In the case of characteristic 2 the ...

The main results: A ring R is CN if and only if for any x ∈ N(R) and y ∈ R, ((1+x)y)n+k = (1+x)n+kyn+k, where n is a fixed positive integer and k = 0, 1, 2; (2) Let R be a CN ring and n ≥ 1. If for any x, y ∈ R\N(R), (xy)n+k = xn+kyn+k, where k = 0, 1, 2, then R is commutative; (3) Let R be a ring and n ≥ 1. If for any x ∈ R\N(R) and y ∈ R, (xy)k = xkyk, k = n, n + 1, n + 2, then R is commutati...

Recent experiments are reviewed that explore the spin states of a ring-shaped manyelectron quantum dot. Coulomb-blockade spectroscopy is used to access the spin degree of freedom. The Zeeman effect observed for states with successive electron number allows to select possible sequences of spin ground states of the ring. Spinpaired orbital levels can be identified by probing their response to mag...