Radial artery access site complications during cardiac procedures,clinical implications and potential solutions: The role of nitric oxide

Percutaneous coronary intervention for the treatment of coronary artery disease is most commonly performed in the UK through the radial artery,as this is considered to be safer than the femoral approach.However,despite improvements in technology and techniques,complications can occur.The most common complication,arterial spasm,can cause intense pain and,in some cases,procedural failure.The incidence of spasm is dependent on several variables,including operator experience,artery size,and equipment used.An antispasmolytic cocktail can be applied to reduce spasm,which usually includes an exogenous nitric oxide(NO)donor(glyceryl trinitrate).NO is an endogenous local vasodilator and therefore is a potential target for anti-spasm intervention.However,systemic administration can result in unwanted side-effects,such as hypotension.A method that adopts local delivery of NO might be advantageous.This review article describes the mechanisms involved in radial artery spasm,discusses the advantages and disadvantages of current strategies to reduce spasm,and highlight the potential of NO-loaded nanoporous materials for use in this setting.

Monitoring dynamics of defects and single Fe atoms in N-functionalized few-layer graphene by in situ temperature programmed scanning transmission electron microscopy

In this study,we aim to contribute an understanding of the pathway of formation of Fe species during top-down synthesis of dispersed Fe on N-functionalized few layer graphene,widely used in electrocatalysis.We use X-ray absorption spectroscopy to determine the electronic structure and coordination geometry of the Fe species and in situ high angle annular dark field scanning transmission electron microscopy combined with atomic resolved electron energy loss spectroscopy to localize these,identify their chemical configuration and monitor their dynamics during thermal annealing.We show the high mobility of peripheral Fe atoms,first diffusing rapidly at the trims of the graphene layers and at temperatures as high as 573 K,diffusing from the edge planes towards in-plane locations of the graphene layers forming three-,four-coordinated metal sites and more complexes polynuclear Fe species.This process occurs via bond C-C breaking which partially reduces the extension of the graphene domains.However,the vast majority of Fe is segregated as a metal phase.This dynamic interconversion depends on the structural details of the surrounding graphitic environment in which these are formed as well as the Fe loading.N species appear stabilizing isolated and polynuclear Fe species even at temperatures as high as 873 K.The significance of our results lies on the fact that single Fe atoms in graphene are highly mobile and therefore a structural description of the electroactive sites as such is insufficient and more complex species might be more relevant,especially in the case of multielectron transfer reactions.Here we provide the experimental evidence of the formation of these polynuclear Fe-N sites and their structural characteristics.

Corrigendum to“Monitoring dynamics of defects and single Fe atoms in N-functionalized few-layer graphene by in situ temperature programmed scanning transmission electron microscopy”[JECHEM 64(2022)520-530]

The authors regret that the word“trim/trims”has been wrongly used in the overall text,and instead the correct word“edge/edges”should have been used.The authors would like to apologise for any inconvenience caused.

nNPipe: a neural network pipeline for automated analysis of morphologically diverse catalyst systems

We describe nNPipe for the automated analysis of morphologically diverse catalyst materials. Automated imaging routines anddirect-electron detectors have enabled the collection of large data stacks over a wide range of sample positions at high temporalresolution. Simultaneously, traditional image analysis approaches are slow and hence unsuitable for large data stacks andconsequently, researchers have progressively turned towards machine learning and deep learning approaches. Previous studiesoften detail work on morphologically uniform material systems with clearly discernible features, limited workable image sizes andtraining data that may be biased due to manual labelling. The nNPipe data-processing method consists of two standaloneconvolutional neural networks that were exclusively trained on multislice image simulations and enables fast analysis of2048 × 2048 pixel images. Inference performance compared between idealised and real industrial catalytic samples and insightsderived from subsequent data analysis are placed into the context of an automated imaging scenario.

Relationship between single and bulk mechanical properties for zeolite ZSM5 spray-dried particles

In this work typical mechanical properties for a catalyst support material, ZSM5 （a spray-dried granular zeolite）, have been measured in order to relate the bulk behaviour of the powder material to the single particle mechanical properties. Particle shape and size distribution of the powders, determined by laser diffraction and scanning electron microscopy （SEM）, confirmed the spherical shape of the spray-dried particles. The excellent flowability of the material was assessed by typical methods such as the Hausner ratio and the Cart index, This was confirmed by bulk measurements of the particle-particle internal friction parameter and flow function using a Schulze shear cell, which also illustrated the low compressibility of the material. Single particle compression was used to characterize single particle mechanical properties such as reduced elastic modulus and strength from Hertz contact mechanics theory. Comparison with surface properties obtained from nanoindentation suggests heterogeneity, the surface being harder than the core. In order to evaluate the relationship between single particle mechanical properties and bulk compression behaviour, uniaxial confined compression was carried out. It was determined that the Adams model was suitable for describing the bulk compression and furthermore that the Adams model parameter, apparent strength of single particles, was in good agreement with the single particle strength determined from single particle compression test.