Puente, en Hagen

The bridge at Hagen-Eskesy, in Germany, was destroyed during the last war, and its reconstruction is part of a local improvement plan. The initial bridge was metallic, but it has now been decided to build a main tied arch, consisting of a box section arch, of 93 m span, and two lateral spans, each 33 m long. These two are open girders, whose top and bottom chords are also hollow box sections. Both the tie members and the main bridging structures are prestressed. The twin arches, from which the deck hangs, are independent. This has made it necessary to attach the arches very rigidly to the stabilising structure, to withstand the powerful effect of the wind forces. Owing to the large dimensions, the possible effect of torsion and buckling under the prestressing forces had to be carefully considered. The twin arches are 12.90 m from each other, and their section is 1.2x1.2 m at the springers, 2x2 m at the quarter span, and 2.4x1.7 at the crown. During the loading and overloading tests, oscilographs were used, to record the effect of mobile loads, and of the increasing overloads. To simulate the effect of running over uneven surfaces, timber beams were placed across the pavement, and loaded vehicles were made to run over them.<br><br>El puente de Hagen-Eckesey (Alemania) fue destruido durante la última guerra mundial, y su reconstrucción ha sido incluida en un plan local de mejoras. El proyecto inicial era metálico, pero razones importantes aconsejaron la solución en arco atirantado, con vigas-cajón como elementos de rigidez en un tramo central de 93 m de luz, y dos tramos laterales, de 33 m de luz, con estructuras aporticadas cuyos cabezales son también vigas huecas tipo cajón. Tanto los tirantes como las piezas de puente son pretensados. Los dos arcos, de los que está suspendido el tablero, son independientes, lo que ha exigido una solidarización con las vigas de rigidez para transmitir los efectos de un viento normal a los soportes y de éstos al suelo. Dada la gran longitud y efectos del pretensado, se estudiaron detenidamente los efectos de torsión y pandeo. Los arcos se han espaciado a 12,90 m, tienen una sección de 1,2x1,3 m en arranques, 2x2 en el cuarto de la luz, y 2,4x1,70 m en la clave. Las pruebas de cargas y sobrecargas se realizaron utilizando oscilógrafos que registraban las oscilaciones de cargas móviles e incrementos de sobrecargas estáticas. Para simular, durante las pruebas, el fenómeno de rodadura sobre un camino ondulado, se colocaron tablones de madera en la calzada para que los vehículos de carga se moviesen sobre ellos

Identification of 9,13-dicis-retinoic acid as a major plasma metabolite of 9-cis-retinoic acid and limited transfer of 9-cis-retinoic acid and 9,13-dicis-retinoic acid to the mouse and rat embryos

9-Cis-retinoic acid (9-cis-RA) has been proposed to be the endogenous ligand of retinoid X receptors. We examined the plasma pharmacokinetics of 9-cis-RA and its metabolites in nonpregnant female NMRI mice after oral dosing with 50 mg 9-cis-RA/kg body weight. Furthermore, we studied the metabolism of 9-cis-RA and its transfer to the embryo following oral administration of the precursor 9-cis-retinaldehyde (9-cis-RAL; 100 mg/kg body weight) to pregnant mice and rats on gestational days 11 and 13, respectively. Following 9-cis-RA administration, plasma levels of 9-cis-RA reached their maximum within 40-60 min and then declined in a monoexponential manner with an apparent half-life of 64 +/- 32 min. A great variety of polar metabolites of 9-cis-RA was found; among them, the beta-glucuronides of 9-cis-RA (9-cis-RAG) and of 9-cis-4-oxo-RA (9-cis-4-oxo-RAG) could be identified. A further prominent polar metabolite of 9-cis-RA in mouse plasma was shown to be an additional RA isomer (distinct from 13-cis-RA and all-trans-RA) whose concentrations weeesimilarly high as those of 9-cis-RA.(ABSTRACT TRUNCATED AT 250 WORDS