Robotic Lepidoptery: Structural Characterization of (mostly) Unexpected Palladium Complexes Obtained from High-Throughput Catalyst Screening

In the course of a high-throughput search for optimal combinations of bidentate ligands with Pd(II) carboxylates to generate oxidation catalysts, we obtained and crystallographically characterized a number of crystalline products. While some combinations afforded the anticipated (L-L)Pd(OC(O)R)_2 structures (L-L = bipyridine, tmeda; R = CH_3, CF_3), many gave unusual oligometallic complexes resulting from reactions such as C−H activation (L-L = sparteine), P−C bond cleavage (L-L = 1,2-bis(diphenylphosphino)ethane, and C−C bond formation between solvent (acetone) and ligand (L-L = 1,4-bis(2,6-diisopropylphenyl)-1,4-diaza-1,3-butadiene). These findings illustrate potential pitfalls of screening procedures based on assuming uniform, in situ catalyst self-assembly

Prospective Durability Testing of a Vascular Access Phantom

Introduction: We assessed the acoustic transmission, image quality, and vessel integrity of the Blue Phantom TM 2 Vessel Original Ultrasound Training Model with repeated use. Methods: The study consisted of two phases. During the first phase, a portion of the Blue Phantom TM rubber matrix (without a simulated vessel) was placed over a two-tiered echogenic structure and was repeatedly punctured with a hollow bore 18-gauge needle in a 1 cm 2 area. During the secon

Ethylene Trimerization Catalysts Based on Chromium Complexes with a Nitrogen-Bridged Diphosphine Ligand Having ortho-Methoxyaryl or ortho-Thiomethoxy Substituents: Well-Defined Catalyst Precursors and Investigations of the Mechanism

Chromium-based ethylene trimerization catalyst precursors ((PNP^(OMe)_(-d)_(12))CrPh_3 (4) and (PNP^(OMe)_(-d)_(12))CrPh_2Cl (7)) having a bis(diphenylphosphino)amine ligand (o-CD_3OC_6H_4)_2PN(CH_3)P(o-CD_3OC_6H_4)_2 ((PNP^(OMe)_(-d)_(12)) = 1) have been prepared and characterized. A thioether analogue (o-CD_3SC_6H_4)_2PN(CH_3)P(o-CD_3SC_6H_4)_2 ((PNP^(SMe)_(-d)_(12)) = 2) and its triphenylchromium complex (PNP^(SMe))CrPh_3 (5) have also been synthesized. The solid-state structures of 4 and 7 display octahedral geometries with a κ^3-(P,P,O) coordination of PNP^(OMe) ligands having chromium−oxygen bond lengths of 2.29−2.44 Å. Compound 5 differs, exhibiting (S,P,S)-κ^3 coordination of the PNP^(SMe) ligand. The deuteromethyl groups allow for ^2H NMR characterization of these paramagnetic complexes in solution. Dynamic exchange processes occur in solution at room temperature to render all four of the methoxy or thioether groups equivalent on the ^2H NMR time scale; two distinct coalescence processes are observed by variable-temperature ^2H NMR spectroscopy for all compounds. The neutral species 4 and 7 react with ethylene (1 atm) by insertion into chromium−phenyl bonds with the release of styrene and ethylbenzene, but 1-hexene is not observed under these conditions. Activation of 4 by protonation and activation of 7 by halide abstraction in the presence of ethylene provide active trimerization catalysts that give turnover numbers for 1-hexene as high as 3000 mol 1-hexene·mol^(-1) Cr. These catalysts display comparable activity and selectivity for 1-hexene compared to the original BP system, where the catalyst is generated in situ from CrCl_3(THF)_3, 1, and MAO. Both the well-defined systems and the CrCl_3(THF)_3/PNP^(OMe)/MAO system provide catalysts that undergo an initiation period followed by an apparent first-order decomposition process. Activated complexes 4 and 7 initiate trimerization primarily through ethylene insertion into the chromium−phenyl bond, followed by β-hydrogen elimination and reductive elimination to give the active species, rather than via reductive elimination of biphenyl

EXOGEN ultrasound bone healing system for long bone fractures with non-union or delayed healing: a NICE medical technology guidance

Open Access. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.This article has been made available through the Brunel Open Access Publishing Fund.A routine part of the process for developing National Institute for Health and Care Excellence (NICE) medical technologies guidance is a submission of clinical and economic evidence by the technology manufacturer. The Birmingham and Brunel Consortium External Assessment Centre (EAC; a consortium of the University of Birmingham and Brunel University) independently appraised the submission on the EXOGEN bone healing system for long bone fractures with non-union or delayed healing. This article is an overview of the original evidence submitted, the EAC’s findings, and the final NICE guidance issued.The Birmingham and Brunel Consortium is funded by NICE to act as an External Assessment Centre for the Medical Technologies Evaluation Programme