GBT model for the buckling analysis of conical shells with stress concentrations

The paper presents a Finite Element formulation based on Generalized Beam Theory (GBT) for the analysis of the linear buckling behaviour of conical shells under various loading and boundary conditions. The GBT approach provides a general solution for the 1st and 2nd order analyses using bar elements capable of describing the global and local deformations. Because of the cross-section variation specific to conical shells, the mechanical and geometric properties are no longer constant along the bar axis as in the case of cylinders and prismatic thin-walled members. This proposed GBT finite element formulation is validated by comparison with results obtained by means of shell finite element analyses. The illustrative examples cover axially compressed members displaying all classical bar boundary conditions. Special attention is dedicated to the effect of pre-buckling stress concentrationspublishersversionpublishe

Role of the Electrophysiologist in the Treatment of Tachycardia-Induced Cardiomyopathy

Tachycardia-induced cardiomyopathy is a systolic cardiac dysfunction given by prolonged elevated heart rates in patients with incessant or frequent tachyarrhythmias. Arrhythmias associated with tachycardiomyopathy can be either supraventricular (atrial tachycardia, atrial flutter, atrial fibrillation, AVNRT, permanent junctional reciprocating tachycardia, high rates of atrial pacing) or ventricular (frequent premature ventricular complexes, right ventricular outflow tract tachycardia, LVOT, left ventricular fascicular tachycardia, bundle-branch reentry or high rate of ventricular pacing). Electrophysiological study confirms the clinical diagnosis of tachycardia-induced cardiomyopathy, reveals the arrhythmia mechanism and facilitates catheter ablation that results in complete recovery of ventricular function. This chapter has two parts: 1. Theoretical insight into the pathogenesis of tachycardia-induced cardiomyopathy, clinical manifestations and therapy. 2. Practical issues: we describe our EP lab’s experience on electrophysiological study and ablation in patients with tachycardia-induced cardiomyopathy. We will present five cases of ablation: PVCs >30,000/24 h, antidromic tachycardia, 2:1 atrial flutter, persistent atrial fibrillation and RVOT PVCs with nonsustained VT

ICD Electrograms in Patients with Brugada Syndrome

In patients with Brugada syndrome, implantable cardioverter‐defibrillator (ICD) is the only demonstrated treatment that prevents sudden cardiac death. The progress in ICD technology improved the diagnosis and efficacy of implantable devices in the management and treatment of ventricular tachycardia (VT) and ventricular fibrillation (VF). Recording of electrical events just before and after a delivered or aborted ICD therapy permits a more accurate characterization of the rhythm but also provides information on the electrical events preceding the arrhythmia. This chapter aims to gain insight into the mechanism of initiation and termination of spontaneous VF by analyzing intracardiac electrograms (IEGM) in Brugada patients implanted with ICDs. It has two parts: (1) update on ICD electrograms in Brugada syndrome patients, where we review the medical literature on ICD electrograms and their use for detecting electrical manifestations of Brugada syndrome, and (2) examples of ICD electrograms, from our own database of patients affected by Brugada syndrome

Cardiac Anatomy for the Electrophysiologist with Emphasis on the Left Atrium and Pulmonary Veins

This chapter aims to provide basic anatomical knowledge for the interventional electrophysiologists to understand catheter placement and ablation targets. We begin with the location of the heart inside the mediastinum, position of cardiac chambers, pericardial space and neighboring structures of the heart. We continue with the right atrium and important structures inside it: sinus node, cavotricuspid isthmus, Koch’s triangle and interatrial septum with fossa ovalis. A special part of this chapter is dedicated to the left atrium and pulmonary veins with the venoatrial junction, important structures for catheter ablation of atrial fibrillation. We finish our description with both ventricles with outflow tracts and the coronary venous system

Assessing Tourists’ Preferences for Recreational Trips in National and Natural Parks as a Premise for Long-Term Sustainable Management Plans

Sustainable tourism management plans rely on relevant and consistent information about factors that can influence the decision to visit a protected area. This paper uses the choice experiment method to investigate tourists’ preferences with regard to recreational trip characteristics in national and natural parks in Romania. An on-site survey questionnaire was administered to visitors. The multinomial logit model was employed to investigate the preference orderings of the identified groups of recreational users. Overall, results indicate that tourists gain benefits after visiting the parks. Main preference differences were found for information sources and location of campsites. Visitors who stated that the park was the main trip destination were willing to have access to more information sources, the marks on trails being insufficient. Camping is preferred only in organized places, expressing the concern for environmental protection. The results of this study have management implications, highlighting the importance of assessing tourists’ preferences as a foundation for developing sustainable tourism strategies

Food Fortification through Innovative Technologies

The chapter aims to approach food fortification naturally as a result of the need for nutritional improvement and therefore underlines sustainable activities that would facilitate effective fortification. The need to fortify food is due to the close link between human, health, and food. The WHO and FAO and other internationally recognized organizations have recognized that there are over 2 billion people worldwide suffering from a variety of micronutrient deficiencies. The interest in the fortification of foods is largely due to bioactive compounds, such as vitamins, minerals, sugars, organic acids, dietary fiber, phenolic compounds, essential amino acids, and antioxidants. The most effective and accessible way of securing the population with vitamins and micronutrients is to fortify additional food and consumer products daily. At the same time, the technology for the fortification of bakery products will also be presented

Recent Advances in Investigation, Prevention, and Management of Healthcare-Associated Infections (HAIs): resistant Multidrug Strain Colonization and Its Risk Factors in an Intensive Care Unit of a University Hospital

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Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10 years; 78.2% included were male with a median age of 37 years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020