Implementing the weakest failure detector for solving consensus

The concept of unreliable failure detector was introduced by Chandra and Toueg as a mechanism that provides information about process failures. This mechanism has been used to solve several agreement problems, such as the consensus problem. In this paper, algorithms that implement failure detectors in partially synchronous systems are presented. First two simple algorithms of the weakest class to solve the consensus problem, namely the Eventually Strong class (⋄S), are presented. While the first algorithm is wait-free, the second algorithm is f-resilient, where f is a known upper bound on the number of faulty processes. Both algorithms guarantee that, eventually, all the correct processes agree permanently on a common correct process, i.e. they also implement a failure detector of the class Omega (Ω). They are also shown to be optimal in terms of the number of communication links used forever. Additionally, a wait-free algorithm that implements a failure detector of the Eventually Perfect class (⋄P) is presented. This algorithm is shown to be optimal in terms of the number of bidirectional links used forever

Surgical multicenter collaborative studies: ¿What happen in Latin America?

Antecedentes: GlobalSurg es un grupo internacional de investigadores que tiene como propósito la conducción y la diseminación de robustos estudios colaborativos, internacionales y multicéntricos. Objetivo: Exponer las estrategias necesarias y las barreras encontradas en la conducción de estudios multicéntricos masivos en cirugía. Método: Durante el segundo semestre del año 2020 se llevó a cabo el estudio Surg-Week Prospective International Cohort Study, hasta la fecha el estudio internacional más grande en el campo de la cirugía, con 141,582 pacientes incluidos. Un total de 4975 miniequipos, de uno a cinco integrantes, recopilaron datos de 116 países de todos los continentes. Resultados: La creación de un sitio web oficial del estudio, reportes con información relevante vía e-mail o grupos vía WhatsApp, conformación de un comité de diseminación del protocolo, dictado de webinars sobre publicaciones recientes del equipo, designación de líderes nacionales e internacionales, y la divulgación por medio de sociedades, fueron las estrategias utilizadas para el desarrollo de la investigación. Sin embargo, las barreras detectadas para llevar a cabo el estudio multicéntrico fueron variadas. Conclusiones: Los trabajos colaborativos permiten establecer redes entre diferentes profesionales con el fin de mejorar la calidad de la gestión, las políticas sanitarias y la atención a los pacientes en tiempos de constante cambio.Background: GlobalSurg is an international group of researchers whose purpose is to conduct and disseminate robust collaborative, international and multicenter studies. Objective: To expose the necessary strategies and the barriers crossed in conducting massive multicenter studies in surgery. Method: During the second semester of 2020, the study Surg-Week Prospective International Cohort Study was carried out. Surg-Week has been the largest international study in the field of surgery to date, with 141,582 patients included. A total of 4975 mini-teams, of between 1 and 5 members, collected data from 116 countries on all continents. Results: The creation of an official website for the study, reports with relevant information via email or groups via WhatsApp, formation of a Dissemination Committee of the protocol, delivery of webinars on recent team publications, appointment of leaders at the national and international level, and outreach through partnerships, were the strategies used for the development of the research. However, the barriers turned out to involve different aspects. Conclusions: Collaborative work allows establishing networks between different professionals with the goal of improving the quality of management, health policies and care of our patients in a timely manner of constant change

Global wealth disparities drive adherence to COVID-safe pathways in head and neck cancer surgery

Peer reviewe

Mortality of emergency abdominal surgery in high-, middle- and low-income countries

Background: Surgical mortality data are collected routinely in high-income countries, yet virtually no low- or middle-income countries have outcome surveillance in place. The aim was prospectively to collect worldwide mortality data following emergency abdominal surgery, comparing findings across countries with a low, middle or high Human Development Index (HDI). Methods: This was a prospective, multicentre, cohort study. Self-selected hospitals performing emergency surgery submitted prespecified data for consecutive patients from at least one 2-week interval during July to December 2014. Postoperative mortality was analysed by hierarchical multivariable logistic regression. Results: Data were obtained for 10 745 patients from 357 centres in 58 countries; 6538 were from high-, 2889 from middle- and 1318 from low-HDI settings. The overall mortality rate was 1⋅6 per cent at 24 h (high 1⋅1 per cent, middle 1⋅9 per cent, low 3⋅4 per cent; P < 0⋅001), increasing to 5⋅4 per cent by 30 days (high 4⋅5 per cent, middle 6⋅0 per cent, low 8⋅6 per cent; P < 0⋅001). Of the 578 patients who died, 404 (69⋅9 per cent) did so between 24 h and 30 days following surgery (high 74⋅2 per cent, middle 68⋅8 per cent, low 60⋅5 per cent). After adjustment, 30-day mortality remained higher in middle-income (odds ratio (OR) 2⋅78, 95 per cent c.i. 1⋅84 to 4⋅20) and low-income (OR 2⋅97, 1⋅84 to 4⋅81) countries. Surgical safety checklist use was less frequent in low- and middle-income countries, but when used was associated with reduced mortality at 30 days. Conclusion: Mortality is three times higher in low- compared with high-HDI countries even when adjusted for prognostic factors. Patient safety factors may have an important role. Registration number: NCT02179112 (http://www.clinicaltrials.gov)

Targeted multifunctional tannic acid nanoparticles

Tannic acid (TA) has multiple effects against cancer, being especially promising in those types that overexpress the epidermal growth factor receptor (EGFR), as TA modulates its activation and downstream signaling pathways, triggering apoptosis. Nonetheless, despite the important role of this receptor in the pathogenesis and progression of a wide variety of tumors, no TA systems targeted to this receptor have been described yet. In this work, we synthesize, characterize by physico-chemical techniques and study the cytotoxic effect and cell uptake of TA nanoparticles targeted to EGFR in both tumoral and normal human skin cells. Our nanoparticles exhibited an extremely high entrapment efficiency, and were only toxic for the tumoral cells. The uptake assay demonstrated that nanoparticles are able to enter the cells through a receptor-mediated mechanism. Furthermore, we have included fluorescent markers in these nanoparticles to combine imaging and therapeutic applications, thus building effectively a multifunctional tool for biomedicine.This work was supported by Junta de Andalucía (Proyecto de Investigación de Excelencia P10-FQM-6615 and PAIDI FQM319), Fondo Europeo de Desarrollo Regional (FEDER-Unión Europea) and Ministerio de Economía y Competitividad, Gobierno de España (Proyecto de Excelencia CTQ2013-48396-P). José M. Oliva-Montero is grateful to the Junta de Andalucía (P10-FQM-06615) for his pre-doctoral fellowship.Peer Reviewe

BJS commission on surgery and perioperative care post-COVID-19

Background: Coronavirus disease 2019 (COVID-19) was declared a pandemic by the WHO on 11 March 2020 and global surgical practice was compromised. This Commission aimed to document and reflect on the changes seen in the surgical environment during the pandemic, by reviewing colleagues experiences and published evidence. Methods: In late 2020, BJS contacted colleagues across the global surgical community and asked them to describe how severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) had affected their practice. In addition to this, the Commission undertook a literature review on the impact of COVID-19 on surgery and perioperative care. A thematic analysis was performed to identify the issues most frequently encountered by the correspondents, as well as the solutions and ideas suggested to address them. Results: BJS received communications for this Commission from leading clinicians and academics across a variety of surgical specialties in every inhabited continent. The responses from all over the world provided insights into multiple facets of surgical practice from a governmental level to individual clinical practice and training. Conclusion: The COVID-19 pandemic has uncovered a variety of problems in healthcare systems, including negative impacts on surgical practice. Global surgical multidisciplinary teams are working collaboratively to address research questions about the future of surgery in the post-COVID-19 era. The COVID-19 pandemic is severely damaging surgical training. The establishment of a multidisciplinary ethics committee should be encouraged at all surgical oncology centres. Innovative leadership and collaboration is vital in the post-COVID-19 era

Delaying surgery for patients with a previous SARS-CoV-2 infection

Not availabl