Genetic Frequencies of Paraoxonase 1 Gene Polymorphisms in Croatian Population

Paraoxonase 1 (PON1), a HDL-associated enzyme, is believed to contribute to the protective effects of HDL by decreasing the generation of lipid peroxidation products during the process of LDL oxidation. It has been reported that polymorphisms in promoter and coding regions of the pon1 gene could affect PON1 activity. The aim of this study was to determine the frequencies of pon1 polymorphisms Q192R, L55M and –108C>T and their influence on PON1 activity in healthy population of Croatia. The following genotype frequencies were determined: 60 % QQ, 34 % QR, 6 % RR for Q192R; 44 % LL, 43 % LM, 13 % MM for L55M; 30 % CC, 48 % CT, 22 % TT for –108C>T polymorphism. Genotypes RR, LL and CC were found to be associated with higher PON1 activity. The most frequent genotypes in healthy Croatian population were QQ, CT and equally present LL and LM

Graded polynomial identities, group actions, and exponential growth of Lie algebras

Consider a finite dimensional Lie algebra L with an action of a finite group G over a field of characteristic 0. We prove the analog of Amitsur's conjecture on asymptotic behavior for codimensions of polynomial G-identities of L. As a consequence, we prove the analog of Amitsur's conjecture for graded codimensions of any finite dimensional Lie algebra graded by a finite Abelian group.Comment: 26 pages; minor misprints were correcte

Magnetic flux tube models in superstring theory

Superstring models describing curved 4-dimensional magnetic flux tube backgrounds are exactly solvable in terms of free fields. We first consider the simplest model of this type (corresponding to `Kaluza-Klein' Melvin background). Its 2d action has a flat but topologically non-trivial 10-dimensional target space (there is a mixing of angular coordinate of the 2-plane with an internal compact coordinate). We demonstrate that this theory has broken supersymmetry but is perturbatively stable if the radius R of the internal coordinate is larger than R_0=\sqrt{2\a'}. In the Green-Schwarz formulation the supersymmetry breaking is a consequence of the presence of a flat but non-trivial connection in the fermionic terms in the action. For R < R_0 and the magnetic field strength parameter q > R/2\a' there appear instabilities corresponding to tachyonic winding states. The torus partition function Z(q,R) is finite for R > R_0 (and vanishes for qR=2n, n=integer). At the special points qR=2n (2n+1) the model is equivalent to the free superstring theory compactified on a circle with periodic (antiperiodic) boundary condition for space-time fermions. Analogous results are obtained for a more general class of static magnetic flux tube geometries including the a=1 Melvin model.Comment: 28 pages, harvmac. Minor changes, final version to appear in NP