Hybridization in some macrocyclic polyacetylenes

The hybridization in several cyclic polyacetylene compounds has been calculated by the maximum overlap method, assuming planar and non-planar geometries of the molecules. In the planar configuration the hybrids describing the molecular skeleton deviate from the corresponding bond directions. We have a few “bent” bonds, but in contrast to the situation in small rings, here the deviation angles are negative, i.e., the hybrids point toward the inside of the ring. Non-planar structures in which acetylene groups are kept in a plane and CCH₂ or CH₂ groups are displaced out of the plane show less deviation from the bond directions of bent bonds. Furthermore, the deviation angles decrease with an increase in the out-of-plane displacement of methylene groups. Finally, when the angle of bending of the molecules approaches 50°, the deviation vanishes, predicting a puckered conformation for the molecules. Correlation between CC stretching vibration frequencies and the corresponding CC bond overlap is discussed.     

Intertwining operator superalgebras and vertex tensor categories for superconformal algebras, II

We construct the intertwining operator superalgebras and vertex tensor categories for the superconformal unitary minimal models and other related models.

     

Cocoa Shell as a Step Forward to Functional Chocolates—Bioactive Components in Chocolates with Different Composition

Chocolate is considered as both caloric and functional food. Its nutritional properties may be improved by addition of fiber; however, this may reduce polyphenols content. The aim of this research was to determine the influence of cocoa shell addition (as a source of fiber) and its combination with different ingredients (cocoa butter equivalents (CBE), emulsifiers, dairy ingredients) on polyphenols of dark and milk chocolates. Total polyphenol (TPC) and total flavonoid (TFC) contents were determined spectrophotometrically, identification and quantification of individual compounds by high pressure liquid chromatography and antioxidant capacity by ferric reducing antioxidant power (FRAP) assay. Results showed that even though addition of cocoa shell to chocolate results in reduced contents of TPC, TFC, and individual compounds, it is not significant compared to ones reported by other authors for commercial chocolates. Other ingredients influence determined values for all investigated parameters; however, additional research is needed to reveal exact mechanisms and implications.     

The <Emphasis Type="Italic">N</Emphasis> = 1 Triplet Vertex Operator Superalgebras

We introduce a newfamily of C ₂-cofinite N = 1 vertex operator superalgebras , m ≥ 1, which are natural super analogs of the triplet vertex algebra family , p ≥ 2, important in logarithmic conformal field theory. We classify irreducible -modules and discuss logarithmic modules. We also compute bosonic and fermionic formulas of irreducible characters. Finally, we contemplate possible connections between the category of -modules and the category of modules for the quantum group , , by focusing primarily on properties of characters and the Zhu’s algebra . This paper is a continuation of our paper Adv. Math. 217, no.6, 2664–2699 (2008). The second author was partially supported by NSF grant DMS-0802962.     

Lattice construction of logarithmic modules for certain vertex algebras

A general method for constructing logarithmic modules in vertex operator algebra theory is presented. By utilizing this approach, we give explicit vertex operator construction of certain indecomposable and logarithmic modules for the triplet vertex algebra W(p){\mathcal{W}(p)} and for other subalgebras of lattice vertex algebras and their N = 1 super extensions. We analyze in detail indecomposable modules obtained in this way, giving further evidence for the conjectural equivalence between the category of W(p){\mathcal{W}(p)}-modules and the category of modules for the restricted quantum group [`(U)]_q(sl₂){\overline{\mathcal{U}}_q(sl_2)} , q = e ^{π i/p} . We also construct logarithmic representations for a certain affine vertex operator algebra at admissible level realized in Adamović (J. Pure Appl. Algebra 196:119–134, 2005). In this way we prove the existence of the logarithmic representations predicted in Gaberdiel (Int. J. Modern Phys. A 18, 4593–4638, 2003). Our approach enlightens related logarithmic intertwining operators among indecomposable modules, which we also construct in the paper.     

2,4-Dioxo-4-(4-hydroxy-6-methyl-2-pyrone-3-yl)butyric acid ethyl ester: Reagent for identifying and estimating metal ions in ring oven analysis

Ligand gave variously colored or fluorescent rings when reacted with several kinds of ions on a ring oven (Schleicher and Schuell filter paper 589²). With ions of Al(III), Be(II), Co(II), Cr(III), Cu(II), Fe(III), and Ni(II) the reactions were sensitive enough to enable application of ring colorimetry or fluorometry (excitation at 366 nm) for quantitation (detection limits, 0.1–2.0 μg of metal). A procedure for estimation of Al(III), Cr(III), and Fe(III) in mixtures was based on reaction with Ligand in combination with EDTA pretreatment, but omitting ion separation. Al(III) could be estimated reliably at its detection-limit-level, in the presence of up to 100 times as much of both Cr(III) and Fe(III).     

"SUNLIGHT"-INDUCED MAMMALIAN CELL KILLING: A COMPARATIVE STUDY OF ULTRAVIOLET AND NEAR-ULTRAVIOLET INACTIVATION

Abstract— We have examined the relationship between the survival curves obtained with UV light (254 nm) and those obtained with a near-UV sburce (Westinghouse Sun Lamps, FS20) simulating sunlight for cultured Chinese hamster cells, C3H mouse cells, and HeLa cells. In no case do the "sunlight" survival curves have the same shape as the UV survival curves. Also, the combined lethal effects of UV and near-UV, sunlight-like exposures are not entirely additive. Hence, we conclude that (1) the cell-killing photolesions induced by these radiations are at most only partly the same, and (2) in view of (I), caution should be exercised in predicting near UV-induced dose-dependencies of other end points based upon observations with UV.     

DNA SINGLE-STRAND LESIONS DUE TO ''SUNLIGHT'' AND UV LIGHT: A COMPARISON OF THEIR INDUCTION IN CHINESE HAMSTER AND HUMAN CELLS, AND THEIR FATE IN CHINESE HAMSTER CELLS

Abstract— It has been shown that the lethal properties of germicidal UV light (254 nm) and sunlight-simulating near UV light are qualitatively different (Elkind et al ., 1978). Further to compare these two radiations, the induction of single-strand DNA breaks (i.e. frank breaks plus alkali-labile lesions) was measured in two cell lines. Equal numbers of breaks in Chinese hamster cells require a dose of UV 5.5% of a near UV dose but in HeLa cells a UV dose of 7.6% of a near-UV dose is required. The rate of break production by these radiations is about 1/10-th of that due to X-rays when a comparison is made on an equal killing dose basis. The inventory of breaks in Chinese hamster cells was also followed and was found to be characteristically different for UV compared to near UV light. These data indicate that significant differences exist, at a molecular level, in the effects produced by ultraviolet and sunlight-simulating light, and further emphasize the need for caution in attempting to extrapolate from observed molecular or biological effects due to the former to those to be expected from the latter.     

Conformational and stereoelectronic control in ring-transformations of cis-4,5-dialkoxytetrahydropurine-2,6,8-triones

Divergent acid-catalysed ring-openings of 4,5-dimethoxytetrahydropurine-2,6,8-triones 2 at position 4, yielding 1-(5-methoxyhydantoin-5-carbonyl)ureas 4 (R⁷ = Me) or 5-methoxy-5-ureido-2,4,6-pyrimidinetriones 5 (R⁷ = H), can be rationalized by assuming a preference for one of two conformational isomers of the cis-fused system, associated with the N-substitution effects. Intramolecular transamidation 5 → 4 presumably occurs via a bicyclic acid aminal type intermediate 3 , heretofore misassigned as the reaction product. A curious base-catalysed rearrangement was encountered with the 5 (R¹ = R³ = Me, R⁷ = H) cases, which afforded 5-methoxy-1,5-bis(methylaminocarbonyl)hydantoins 7 . Remarkable stability of the conformationally rigid propellane type 4,5-ethylenedioxytetrahydropurine-2,6,8-triones 9 toward acids, shows that the mode of ring-opening at position 4 is controlled by powerful Stereoelectronic factors. However, an alternative ring-opening at the 1,6-bond has occurred on heating aqueous solutions of 9a (R⁷ = H); the ensuing decarboxylative rearrangement leads to 1,3-dimethylallantoin ( 12 ) and its precursor, 1-(2-hydroxyethoxy)-2,4-dimethyl-3,7-dioxo-2,4,6,8-tetraazabicyclo[3.3.0]octane( 11 ).