What should be known prior to performing EUS exams? (Part II)

In "What should be known prior to performing EUS exams, Part I," the authors discussed the need for clinical information and whether other imaging modalities are required before embarking EUS examinations. Herewith, we present part II which addresses some (technical) controversies how EUS is performed and discuss from different points of view providing the relevant evidence as available. (1) Does equipment design influence the complication rate? (2) Should we have a standardized screen orientation? (3) Radial EUS versus longitudinal (linear) EUS. (4) Should we search for incidental findings using EUS

Revisiting in vivo staining with alizarin red S - a valuable approach to analyse zebrafish skeletal mineralization during development and regeneration

Background The correct evaluation of mineralization is fundamental for the study of skeletal development, maintenance, and regeneration. Current methods to visualize mineralized tissue in zebrafish rely on: 1) fixed specimens; 2) radiographic and μCT techniques, that are ultimately limited in resolution; or 3) vital stains with fluorochromes that are indistinguishable from the signal of green fluorescent protein (GFP)-labelled cells. Alizarin compounds, either in the form of alizarin red S (ARS) or alizarin complexone (ALC), have long been used to stain the mineralized skeleton in fixed specimens from all vertebrate groups. Recent works have used ARS vital staining in zebrafish and medaka, yet not based on consistent protocols. There is a fundamental concern on whether ARS vital staining, achieved by adding ARS to the water, can affect bone formation in juvenile and adult zebrafish, as ARS has been shown to inhibit skeletal growth and mineralization in mammals. Results Here we present a protocol for vital staining of mineralized structures in zebrafish with a low ARS concentration that does not affect bone mineralization, even after repetitive ARS staining events, as confirmed by careful imaging under fluorescent light. Early and late stages of bone development are equally unaffected by this vital staining protocol. From all tested concentrations, 0.01 % ARS yielded correct detection of bone calcium deposits without inducing additional stress to fish. Conclusions The proposed ARS vital staining protocol can be combined with GFP fluorescence associated with skeletal tissues and thus represents a powerful tool for in vivo monitoring of mineralized structures. We provide examples from wild type and transgenic GFP-expressing zebrafish, for endoskeletal development and dermal fin ray regeneration

Revisiting Some Developments of Boundary Elements for Thick Plates in Brazil

This work reviews the developments of Boundary Element Method formulations to solve several types of plate bending problems, including non-linear bending. The formulation is developed and solved using the standard BEM procedure, and different integration approaches were discussed and tested. Object oriented implementation issues are commented. Results were obtained for linear and non-linear elastic bending as well as buckling of selected cases of thick plates, including cases of step variation in thickness under large displacements regime

Fracture initiation in a lamellar alloy

The possibility of slip bands providing sites for fracture initiation within composites of lamellar construction is investigated. It is proposed that the tips of these bands, which terminate at the composite\u27s bimetallic interfaces, are the specific locations of fracture initiation. Application of a dislocation intensity factor criterion allowed the applied stress at which cracks may be initiated to be calculated. The predictions compare favorably with experimental data. The dependence of the fracture initiation stress calculated from this model is shown to follow a Hall-Petch relationship. © 1986 Martinus Nijhoff Publishers

Propagation of S-H waves in laminated composites: A gradient elasticity approach

The propagation of shear waves in a stratified, infinite medium consisting of alternating layers of two homogeneous, isotropic materials is studied within the framework of gradient elasticity. The special form of gradient elasticity employed in this study is introduced. The classical solution is analyzed in detail, and compared with the solution obtained using this form of the special form of gradient elasticity. The advantages of the proposed constitutive equation for modeling the mechanical behavior of composites is briefly discussed

Impact of the COVID-19 pandemic on gastrointestinal endoscopy in Africa

Background and study aims  As with all other fields of medical practice, gastrointestinal endoscopy has been impacted by the COVID-19 pandemic. However, data on the impact of the pandemic in Africa, especially sub-Saharan Africa are lacking. Methods  A web-based survey was conducted by the International Working Group of the European Society for Gastrointestinal Endoscopy and the World Endoscopy Organization to determine the impact and effects the COVID-19 pandemic has had on endoscopists in African countries. Results  Thirty-one gastroenterologists from 14 countries in north, central, and sub-Saharan Africa responded to the survey. The majority of respondents reduced their endoscopy volume considerably. Personal protective equipment including FFP-2 masks were available in almost all participating centers. Pre-endoscopy screening was performed as well. Conclusion  The COVID-19 pandemic has had a substantial impact on gastrointestinal endoscopy in most African countries; however, the impact may not have been as devastating as expected

European Society of Gastrointestinal Endoscopy, European Society of Gastroenterology and Endoscopy Nurses and Associates, and the European Society of Anaesthesiology Guideline: Non-anesthesiologist administration of propofol for GI endoscopy

Propofol sedation by non-anesthesiologists is an upcoming sedation regimen in several countries throughout Europe. Numerous studies have shown the efficacy and safety of this sedation regimen in gastrointestinal endoscopy. Nevertheless, this issue remains highly controversial. The aim of this evidence- and consensus-based set of guideline is to provide non-anesthesiologists with a comprehensive framework for propofol sedation during digestive endoscopy. This guideline results from a collaborative effort from representatives of the European Society of Gastrointestinal Endoscopy (ESGE), the European Society of Gastroenterology and Endoscopy Nurses and Associates (ESGENA) and the European Society of Anaesthesiology (ESA). These three societies have endorsed the present guidelin