Minimum vertex degree conditions for loose Hamilton cycles in 3-uniform hypergraphs

We investigate minimum vertex degree conditions for 3-uniform hypergraphs which ensure the existence of loose Hamilton cycles. A loose Hamilton cycle is a spanning cycle in which only consecutive edges intersect and these intersections consist of precisely one vertex.     

Photodynamics of the bacteriochlorophyll-carotenoid system. 2. Influence of central metal,solvent and beta-carotene on photobleaching of bacteriochlorophyll derivatives

Bacteriochlorophyll (BChl) derivatives (with central Mg replaced by metal "M") ([M]-BChl with M = 2H, Mg, Zn, Pd, Cu) have been investigated for their photodynamic capacity and stability toward photodegradation in organic solvents and aqueous micellar solution. A protocol has been developed for screening new sensitizers. BChl and [Zn]-BChl are efficient sensitizers, but they are also quickly degraded by the reactive oxygen species (ROS) produced by autosensitization, as well as by hetero-sensitization with 17(4)-methyl-13(2)-demethoxycarbonyl-pheophorbide a (MPP). Photostable [Cu]-BChl is a poor sensitizer, whereas [Pd]-BChl and bacteriopheophytin a are not only very efficient sensitizers but are also very stable toward ROS. beta-Carotene is no efficient physical quencher of ROS in the system; rather, it acts as a photochemical quencher that competes with [M]-BChl and undergoes photooxygenation at high rates. Photolability seems to depend on the pigment oxidation potential and, in parallel, on the presence of central metals preferring coordination numbers higher than 4, whereas photodynamic capacity depends on long excited state life-times of the pigment or efficient intersystem crossing (or both).     

The first coordination compound containing three different types of spin carriers: 2p-3d-4f (TCNQ.-, Cu2+ and Gd3+)

A novel heterospin system, [(CuL)2Gd(TCNQ)2].TCNQ-.CH3OH.2CH3CN, is obtained by reacting the mononuclear complex, [CuL], with gadolinium(III) nitrate, followed by the substitution of the nitrato ions with anionic organic radicals.     

Generalized ellipsometry for biaxial absorbing materials: determination of crystal orientation and optical constants of Sb(2)S(3)

We demonstrate generalized ellipsometry for precise measurement of the principal indices of refraction, the extinction coefficients, and the orientations of the crystal a, b, and c axes of orthorhombic absorbing materials. Stibnite (Sb(2)S(3)) single crystals cut approximately parallel to (100), (010), (001), and (313) are studied at a representative wavelength of 589 nm. The (313) surface is sufficient for retrieval of all optical constants. The expected effects of surface over-layer formation are removed numerically. We propose generalized ellipsometry as a powerful tool for measurement of anisotropic optical function spectra of biaxial materials.