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The electronic structure and derived optical properties of five synthesized metal-dicyanoaurate(I), (K)M[Au(CN)2], (M = Mn, Co, Ni, Zn and Cd), coordination polymers are described from a combined experimental analysis and theoretical study based on density functional theory. In this sense, the topological features that influence the electronic structure, which in turn give rise to electronic transitions associated with the band gap energy, are studied from first principles calculations (with hybrid HSE06 and GGA-PBE density functionals) and electronic spectroscopy. The impact of gold (through spin-orbit coupling) and aurophilic interactions on the electronic transitions that gives rise to optical properties is described. The calculated projected density of states and band dispersion diagrams shed light on the molecular orbital distribution and the role of a dicyanoaurate(I) molecular block as the origin of the optical properties. Infrared, Raman and ultraviolet-visible spectroscopic analyses reveal the effect that charge transfer interactions, of a metal → ligand and metal → metal nature, have on the electronic behavior within the solids through association with the polarizing power of transition metals and gold atoms.

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Objetivo. Evaluar el efecto de la oferta de kikuyo y el tercio de lactancia sobre el perfil de ácidos grasos en la grasa láctea de bovinos en pastoreo. Materiales y métodos. Se utilizaron 18 vacas de la raza Holstein con un peso promedio de 585 ±10 kg entre dos y cuatro partos, en primer y segundo tercio de lactancia. Las vacas se dividieron en tres grupos y fueron asignados al azar a uno de los tres tratamientos (ofertas de 2.6; 3.3 ó 4.0 kg MS/100 kg PV). Se determinó el perfil de ácidos grasos en la leche los días 14 y 21 del periodo experimental. Resultados. Los ácidos grasos C6:0, C16:0, C18:1c9 y C18:3 permanecieron constantes entre las diferentes ofertas de forraje y tercios de lactancia. En las mayores ofertas se presentó un aumento entre el día 14 y 21 de los ácidos C10:0 y C12:0 mientras que disminuyeron su concentración en estos mismos días los ácidos C18:1t11, C18:2c9c12, C18:2c9t11 y poliinsaturados. Se presentó una mayor concentración del ALC en animales de segundo tercio respecto a los de primero. Conclusiones. Debido a las variaciones entre los días de muestreo en el perfil de ácidos grasos de la grasa láctea fue imposible determinar si el aumento en la oferta mejora las concentraciones de ácidos grasos que han presentado efecto benéfico en la salud humana. La movilización de reservas de grasa podría explicar el comportamiento diferente de la concentración de ácidos grasos entre los días de recolección de muestras.

Objective. To evaluate the effect of kikuyu offer and stage of lactation on fatty acids profile on milk fat of grazing dairy bovines. Materials and methods. Eighteen Holstein cows with average weight of 585±10 Kg in two to four calvings on first and second lactation stages. Cows were divided in three groups and assigned randomly to one of three treatments (pasture allowances of 2.6, 3.3 or 4.0 KgDM/100 Kg LW). Milk fatty acid profiles were determined on days 14 and 21 of the experimental period. Results. Fatty acids C6:0, C16:0, C18:1cis9, C18:3 remained constant between different forage allowances and lactation stage were used. On the treatments of highest allowance, there was an increase between days 14 and 21 of C10:0 andC12:0 acids while C18:1t11,C18:2c9c12, C18:2c9,t11, and polyunsaturated fatty acids decreased their concentration. The lowest allowance had a different behavior. A higher concentration of ALC was observed in animals of second stage compared to first stage of lactation. Conclusions. It was not possible to conclude on the effects of forage allowance on the fatty acid profile of milk, due to variations between sampling dates. It is possible that mobilization of fat storage can explain the different behavior of fatty acid concentrations between sampling days.

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We determined the capacity of grapefruit juice (GJ) to inhibit the rate of micronucleated polychromatic erythrocytes (MNPE) in mice treated with benzo(a)pyrene (BaP), an environmental contaminant that is biotransformed by Cyp1a1 and is a strong genotoxic agent. For this study, we administered 4.1, 20.8, and 41.6 µl/g body weight (b.w.) of GJ to BaP-treated mice (340 mg/kg). We found a significant decrease in the frequency of MNPE at 48 and 72 h compared to BaP-only treated animals. In turn, no prevention of the cytotoxic damage induced by BaP was found. We next explored whether GJ's antigenotoxic mechanism of action was related to an inhibitory effect on the activity of the Cyp1a1 enzyme. A reduction in microsomal hepatic and intestinal ethoxyresorufin-O-deethylase (EROD) activity of 20% and 44%, respectively, was found in mice treated with BaP and GJ compared to BaP-only treated animals. Furthermore, when EROD inhibition was tested in vitro, we found a concentration-dependent EROD inhibition by GJ, which reached 85% of the maximum level. Together, these results suggest that the protective effect of GJ against the genotoxicity of BaP may be related to the inhibition of Cyp1a1 enzyme activity.

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