[Voyage en Italie : 1824-1830]. , Pompeia. Forum : [détails d'un chapiteau ionique et d'un pilastre dorique] : [dessin] / [Henri Labrouste ?]

Référence bibliographique : Weigert, 383

[Voyage en Italie : 1824-1830]. , Forum : [plan, élévation d'ensemble et détail d'élévation d'un piédestal] : [dessin] / h. L. [Henri Labrouste]

Référence bibliographique : Weigert, 384

Determination of entrance loss coefficients for pre-cast reinforced Concrete Box Culverts, December 2012

There is an increased interest in constructing Pre-Cast (PC) Twin and Triple Reinforced Concrete Box (RCB) culverts in Iowa due to the efficiency associated with their production in controlled environment and decrease of the construction time at the culvert sites. The design of the multi-barrel PC culverts is, however, based on guidelines for single-barrel cast-inplace (CIP) culverts despite that the PC and CIP culverts have different geometry. There is scarce information for multiplebarrel RCB culverts in general and even fewer on culverts with straight wingwalls as those designed by Iowa DOT. Overall, the transition from CIP to PC culverts requires additional information for improving the design specifications currently in use. Motivated by the need to fill these gaps, an experimental study was undertaken by IIHR-Hydroscience & Engineering. The goals of the study are to document flow performance curves and head losses at the culvert entrance for a various culvert geometry, flow conditions, and settings. The tests included single-, double- and triple-barrel PC and CIP culverts with two span-to-rise ratios set on mild and steep slopes. The tests also included optimization of the culvert geometry entrance by considering various configurations for the top bevel. The overall conclusion of the study is that by and large the current Iowa DOT design specifications for CIP culverts can be used for multi-barrel PC culvert design. For unsubmerged flow conditions the difference in the hydraulic performance curves and headloss coefficients for PC and CIP culverts are within the experimental uncertainty. Larger differences (specified by the study) are found for submerged conditions when the flow is increasingly constricted at the entrance in the culvert. The observed differentiation is less important for multi-barrel culverts as the influence of the wingwalls decreases with the increase of the number of barrels.

PchR-box recognition by the AraC-type regulator PchR of Pseudomonas aeruginosa requires the siderophore pyochelin as an effector.

Under iron limitation, the opportunistic human pathogen Pseudomonas aeruginosa produces the siderophore pyochelin. When secreted into the extracellular environment, pyochelin complexes ferric ions and delivers them, via the outer membrane receptor FptA, to the bacterial cytoplasm. Extracellular pyochelin also acts as a signalling molecule, inducing the expression of pyochelin biosynthesis and uptake genes by a mechanism involving the AraC-type regulator PchR. We have identified a 32 bp conserved sequence element (PchR-box) in promoter regions of pyochelin-controlled genes and we show that the PchR-box in the pchR-pchDCBA intergenic region is essential for the induction of the pyochelin biosynthetic operon pchDCBA and the repression of the divergently transcribed pchR gene. PchR was purified as a fusion with maltose-binding protein (MBP). Mobility shift assays demonstrated specific binding of MBP-PchR to the PchR-box in the presence, but not in the absence of pyochelin and iron. PchR-box mutations that interfered with pyochelin-dependent regulation in vivo, also affected pyochelin-dependent PchR-box recognition in vitro. We conclude that pyochelin, probably in its iron-loaded state, is the intracellular effector required for PchR-mediated regulation. The fact that extracellular pyochelin triggers this regulation suggests that the siderophore can enter the cytoplasm.

[Voyage en Italie : 1824-1830]. , Du portique près du forum triangulaire : [détail d'un chapiteau ionique] : [dessin] / h. L. [Henri Labrouste]

Référence bibliographique : Weigert, 388

[Voyage en Italie : 1824-1830]. , Portique du Forum : [plan d'ensemble] : [dessin] / h. L. [Henri Labrouste]

Référence bibliographique : Weigert, 381

[Voyage en Italie : 1824-1830]. , Du portique du Forum de Pompeia, au huitième de l'Exécution : [élévation et coupe d'un détail de l'architrave, élévation d'un chapiteau dorique, coupe et vue perspective d'un détail de la restauration] : [dessin] / h. L. [Henri Labrouste]

Référence bibliographique : Weigert, 382

[Voyage en Italie : 1824-1830]. , [Bassin de fontaine orné d'une tête de faune ou d'un masque à l'entrée du forum triangulaire et pied d'une fontaine] : [vue perspective et profil d'un pied, vue perspective du bassin] : [dessin] / h. L. [Henri Labrouste]

Référence bibliographique : Weigert, 369

[Voyage en Italie : 1824-1830]. , Forum. Temple de Jupiter : [plan d'ensemble du temple et d'une partie du forum] : [dessin] / h. L. [Henri Labrouste]

Référence bibliographique : Weigert, 370

[Voyage en Italie : 1824-1830]. , Coupe du Temple de Jupiter. Coupe du Forum. Sur une Echelle de 001 PM : [coupe longitudinale sur le temple, coupe transversale sur le forum] : [dessin] / h. L. [Henri Labrouste]

Référence bibliographique : Weigert, 371