The highly polarized open cluster Trumpler 27

We have carried out multicolor linear polarimetry (UBVRI) of the brightest stars in the area of the open cluster Trumpler 27. Our data show a high level of polarization in the stellar light with a considerable dispersion, from $P = 4$ to $P = 9.5$. The polarization vectors of the cluster members appear to be aligned. Foreground polarization was estimated from the data of some non-member objects, for which two different components were resolved: the first one associated with a dust cloud close to the Sun producing $P_{\lambda max}=1.3$ and $\theta=146$ degrees, and a second component, the main source of polarization for the cluster members, originated in another dust cloud, which polarizes the light in the direction of $\theta= 29.5$ degrees. From a detailed analysis, we found that the two components have associated values $E_{B-V} < 0.45$ for the first one, and $E_{B-V} > 0.75$ for the other. Due the difference in the orientation of both polarization vectors, almost 90 degrees (180 degrees at the Stokes representation), the first cloud ($\theta \sim 146$ degrees) depolarize the light strongly polarized by the second one ($\theta \sim 29.5$ degrees).Comment: 12 Pages, 6 Figures, 2 tables (9 Pages), accepted for publication in A

Rhodotorula minuta-mediated bioreduction of 1,2-diketones

The reduction of cyclic and acyclic 1,2-diketones was investigated by employing whole cells of the yeast Rhodotorula minuta as biocatalyst. The reactions showed a variable degree of regio- and enantioselectivity depending on the nature of the substrate. In the case of cyclic diketones, the reduction afforded a mixture of diastereomeric diols only. The reduction of acyclic diketones allowed production of both the hydroxy ketone and the diol, in a two-step reaction. The first step was highly regio- and stereoselective, affording the hydroxy ketone of (S)-configuration with high enantiomeric excess. After longer reaction times the corresponding (S,S)-diols were obtained in high yield and diastereomeric excess. © 2010 Informa UK Ltd.Fil: Monsalve, Leandro Nicolas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos en Química Orgánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de Microanálisis y Métodos Físicos en Química Orgánica; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; ArgentinaFil: Cerruti, Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Ingeniería Química; ArgentinaFil: Galvagno, Miguel Angel. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Ingeniería Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Baldessari, Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos en Química Orgánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de Microanálisis y Métodos Físicos en Química Orgánica; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentin