Chemocatalytic Conversion of Dinitrogen to Ammonia Mediated by a Tungsten Complex.

Whereas molybdenum dinitrogen complexes have played a major role as catalytic model systems of nitrogenase, corresponding tungsten complexes were in most cases found to be catalytically inactive. Herein, we present a modified pentadentate tetrapodal (pentaPod) phosphine ligand in which two dimethylphosphine groups of the pentaPod (P5) ligand have been replaced with phospholanes (Pln). The derived molybdenum complex [Mo(N)P5] generates 22 and the analogous tungsten complex [W(N)P5] 7 equivalents of NH from N in the presence of 180 equivalents of SmI(THF)/HO, rendering the latter the first tungsten complex chemocatalytically converting N to NH.

[Contrast medium: an unpredictable ally].

Reactions to contrast media are unpredictable. This article examines the use of iodinated and gadolinium-based contrast agents in medical imaging. It explores their clinical presentation, associated risk factors, precautions prior to their administration, and treatment options in the event of a reaction.

Relation between Shear Stresses and Flexural Tensile Stresses from Standardized Tests of Extracted Prismatic Specimens of an SFRC Bridge Girder.

Experimental research on the direct shear behavior of fiber-reinforced concrete is often carried out using prisms molded with specific dimensions for a standardized test. However, the flow of fresh concrete in these molds can be different than in the case of a full-scale structural element. This is important considering that the flow direction highly influences the distribution and orientation of fibers.

[Interprofessional simulation in emergency medicine].

Teamwork is essential in emergency medicine, but in practice it can be polluted by communication difficulties, a lack of understanding of everyone's roles and responsibilities, and a discordant definition of operating methods and objectives. Today, there is a strong awareness of the need to train medical and healthcare teams in interprofessional collaborative practice to learn how to work as a team, reduce medical errors and improve patient safety. Simulation is a recognized and effective pedagogical modality for achieving these objectives.