In Vivo Degradation Behavior of the Magnesium Alloy LANd442 in Rabbit Tibiae

In former studies the magnesium alloy LAE442 showed promising in vivo degradation behavior and biocompatibility. However, reproducibility might be enhanced by replacement of the rare earth composition metal "E" by only a single rare earth element. Therefore, it was the aim of this study to examine whether the substitution of "E" by neodymium ("Nd") had an influence on the in vivo degradation rate. LANd442 implants were inserted into rabbit tibiae and rabbits were euthanized after 4, 8, 13 and 26 weeks postoperatively. In vivo μCT was performed to evaluate the in vivo implant degradation behaviour by calculation of implant volume, density true 3-D thickness and corrosion rates. Additionally, weight loss, type of corrosion and mechanical stability were appraised by SEM/EDS-analysis and three-point bending tests. Implant volume, density and true 3-D thickness decreased over time, whereas the variance of the maximum diameters within an implant as well as the corrosion rate and weight loss increased. SEM examination revealed mainly pitting corrosion after 26 weeks. The maximum bending forces decreased over time. In comparison to LAE442, the new alloy showed a slower, but more uneven degradation behavior and less mechanical stability. To summarize, LANd442 appeared suitable for low weight bearing bones but is inferior to LAE442 regarding its degradation morphology and strength

Examining the strategic impact of using enterprise systems in manufacturing businesses

This study examines the strategic impact of enterprise system use at the business unit level. It does this from two different strategic perspectives, the resource-based and the activity-based views. This study also looks at the context of an enterprise system's implementation in order to identify the impact that it has on the realisation of the system's benefits. The purpose of this study is to examine whether the impact of enterprise systems goes beyond cost savings and other operational improvements. It also aims to shed some light on the 'enterprise system paradox', i. e. the apparent contrast between their evident popularity and widespread use, and the observed high variance of implementation success rates. Moreover, it aims at making a contribution towards the development of a theory that links the use of enterprise systems to firm performance, and predicts how contextual factors can affect this chain of causality. The lack of theory in this field and the ambiguity surrounding the enterprise system paradox provide motivation for this research. Data was collected in a series of five in-depth case studies. A positive impact was found on relevant strategic resources, dynamic capabilities and critical value chain elements; thus highlighting the strategic relevance of enterprise systems. At- the same time, a substantial variance in impact was found, providing further evidence for the enterprise system paradox. Some of this variance was explained by the use of business process reengineering as part of an enterprise system's implementation, and the integration of formerly separate information systems into a single system. The product/process structure of a business and its strategic configuration were also found to explain differences in the strategic impact of enterprise systems. Some variance, however, remains unexplained. This highlights the infant stage of enterprise system research

Cooperation, Norms, and Revolutions: A Unified Game-Theoretical Approach

Cooperation is of utmost importance to society as a whole, but is often challenged by individual self-interests. While game theory has studied this problem extensively, there is little work on interactions within and across groups with different preferences or beliefs. Yet, people from different social or cultural backgrounds often meet and interact. This can yield conflict, since behavior that is considered cooperative by one population might be perceived as non-cooperative from the viewpoint of another. To understand the dynamics and outcome of the competitive interactions within and between groups, we study game-dynamical replicator equations for multiple populations with incompatible interests and different power (be this due to different population sizes, material resources, social capital, or other factors). These equations allow us to address various important questions: For example, can cooperation in the prisoner's dilemma be promoted, when two interacting groups have different preferences? Under what conditions can costly punishment, or other mechanisms, foster the evolution of norms? When does cooperation fail, leading to antagonistic behavior, conflict, or even revolutions? And what incentives are needed to reach peaceful agreements between groups with conflicting interests? Our detailed quantitative analysis reveals a large variety of interesting results, which are relevant for society, law and economics, and have implications for the evolution of language and culture as well

Entre o passado europeu e o futuro americano: dois ensaios sobre o Brasil da década de 1930

O artigo explora a ideia de Europa concebida por Stefan Zweig e Hermann Ullmann nos livros quase homônimos sobre o Brasil, escritos no final da década de 1930 e início de 1940. No contexto político do entreguerras marcado pela ascensão do nazismo, pergunta-se em que sentido a Europa continua a servir de modelo civilizatório e qual a dimensão crítica que se expressa em concepções que invertem os papéis da Europa e do Brasil. Observa-se ruptura parcial com visões dicotômicas e hierárquicas acerca das relações entre o Velho e o Novo Mundo e sugerem-se novas formas de relação entre essas regiões no contexto mundial

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Suitability of subsequently installed vibrating wire sensors for direct stress measurement in concrete and mortar

Over the past decades, a major part of the building infrastructure has aged and is now in need of repair. In order to ease the repair backlog and to be able to distinguish between urgent and long-term repair needs, it is advisable to install a monitoring system to the structure. This monitoring is, among others, often based on periodical strain or deformation measurements, as they provide a direct indication of the effect of external loads on the structure (crack opening or heavy deformations). Still, most of the available monitoring systems cannot be installed subsequently or they are limited to measurements on the surface. For monitoring the structural behaviour inside specific components, the use of a sensor system based on the vibrating wire measuring principle appears promising. This sensor system has proven itself in geotechnical engineering. However, there is no profound experience of using this system in concrete structures. Therefore, the aim of the work presented in this paper was to investigate the suitability of these sensors for stress measurement in concrete and mortar. We will furthermore give an outlook on a possible application for monitoring reinforced concrete structures.</jats:p