We report a quantitative kinetic evaluation and study of support effects for partial alkyne hydrogenation using oleylaminecapped Au colloids as catalyst precursors. The amine capping agents can be removed under reducing conditions, generating supported Au nanoparticles of~2.5 nm in diameter. The catalysts showed high alkene selectivity (> 90 %) at all conversions during alkyne partial hydrogenation. Catalytic activity, observed rate constants, and apparent activation energies (25-40 kJ/mol) were similar for all Au catalysts, indicating support effects are relatively small. Alkyne adsorption, probed with FTIR and DFT, showed adsorption on the support was associated with hydrogen-bonding interactions. DFT calculations indicate strong alkyne adsorption on Au sites, with the strongest adsorption sites at the metal-support interface (MSI). The catalysts had similar hydrogen reaction orders (0.7-0.9), and 1octyne reaction orders (~À 0.2), suggesting a common mechanism. The reaction kinetics are most consistent with a mechanism involving the non-competitive activated adsorption of H 2 on an alkyne-covered Au surface.[a] Dr.

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The technical evolution of ultrasonic equipment provides a high resolution imaging analysis of the vessel wall and thereby offers new possibilities in diagnosing very early atherosclerotic changes. The typical B-mode image in human and animal arteries shows parallel wall contures enclosing a hypoechoic space. In this study in Vitro- and in Vivo-experiments in rabbit aortas document the distance between these contures correlating histologically with a high cholesterol diet caused a broadening of the hypoechoic space in the rabbit aortic vessel wall. The data demonstrate that high resolution Duplex Sonography is a usefull noninvasive approach for the detection of very early atherosclerotic changes in arterial vessel walls in a stage before plaques can be identified.

Background and Objective: The purpose of this article is to demonstrate the optical coherence tomography angiography (OCTA) Analysis Toolkit (OAT), a custom-designed software package, as a repeatable and reproducible tool for computing OCTA metrics across different devices. Materials and Methods: Fourteen participants were imaged using three devices. Foveal avascular zone, vessel index, vessel length index, and vessel diameter index were calculated using the OAT. Repeatability and reproducibility were assessed using the coefficient of variation and interclass correlation coefficient (ICC). Results: Analysis of identical images demonstrated perfect levels of repeatability for all metrics (coefficient of variation 0%), which was a consequence of the software being deterministic (ie, producing the same outputs for the same inputs). Foveal avascular zone ICC values were in the excellent-to-good range (I CC > 0.6) for all devices. All values for vessel index (VI), vessel length index, and vessel diameter index fell in the good-to-fair (I CC > 0.4) or excellent-to-good range, except for vessel index analysis in the Cirrus device (I CC = 0.34). Conclusions: The OAT appears to be a reliable tool that may enable comparison between OCTA data sets acquired on different imaging instruments, thereby facilitating a more consistent approach to OCTA analysis. [ Ophthalmic Surg Lasers Imaging Retina 2023;54:114–122.]

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