Three-dimensional magnetic flux-closure patterns in mesoscopic Fe islands

We have investigated three-dimensional magnetization structures in numerous mesoscopic Fe/Mo(110) islands by means of x-ray magnetic circular dichroism combined with photoemission electron microscopy (XMCD-PEEM). The particles are epitaxial islands with an elongated hexagonal shape with length of up to 2.5 micrometer and thickness of up to 250 nm. The XMCD-PEEM studies reveal asymmetric magnetization distributions at the surface of these particles. Micromagnetic simulations are in excellent agreement with the observed magnetic structures and provide information on the internal structure of the magnetization which is not accessible in the experiment. It is shown that the magnetization is influenced mostly by the particle size and thickness rather than by the details of its shape. Hence, these hexagonal samples can be regarded as model systems for the study of the magnetization in thick, mesoscopic ferromagnets.Comment: 12 pages, 11 figure

EPIdemiology of Surgery-Associated Acute Kidney Injury (EPIS-AKI) : Study protocol for a multicentre, observational trial

More than 300 million surgical procedures are performed each year. Acute kidney injury (AKI) is a common complication after major surgery and is associated with adverse short-term and long-term outcomes. However, there is a large variation in the incidence of reported AKI rates. The establishment of an accurate epidemiology of surgery-associated AKI is important for healthcare policy, quality initiatives, clinical trials, as well as for improving guidelines. The objective of the Epidemiology of Surgery-associated Acute Kidney Injury (EPIS-AKI) trial is to prospectively evaluate the epidemiology of AKI after major surgery using the latest Kidney Disease: Improving Global Outcomes (KDIGO) consensus definition of AKI. EPIS-AKI is an international prospective, observational, multicentre cohort study including 10 000 patients undergoing major surgery who are subsequently admitted to the ICU or a similar high dependency unit. The primary endpoint is the incidence of AKI within 72 hours after surgery according to the KDIGO criteria. Secondary endpoints include use of renal replacement therapy (RRT), mortality during ICU and hospital stay, length of ICU and hospital stay and major adverse kidney events (combined endpoint consisting of persistent renal dysfunction, RRT and mortality) at day 90. Further, we will evaluate preoperative and intraoperative risk factors affecting the incidence of postoperative AKI. In an add-on analysis, we will assess urinary biomarkers for early detection of AKI. EPIS-AKI has been approved by the leading Ethics Committee of the Medical Council North Rhine-Westphalia, of the Westphalian Wilhelms-University Münster and the corresponding Ethics Committee at each participating site. Results will be disseminated widely and published in peer-reviewed journals, presented at conferences and used to design further AKI-related trials. Trial registration number NCT04165369

Magnetic surface domain imaging of uncapped epitaxial FeRh(001) thin films across the temperature-induced metamagnetic transition

The surface magnetic domain structure of uncapped epitaxial FeRh/MgO(001) thin films was imaged by in-situ scanning electron microscopy with polarization analysis (SEMPA) at various temperatures between 122 and 450 K. This temperature range covers the temperature-driven antiferromagnetic-to-ferromagneticphase transition in the body of the films that was observed in-situ by means of the more depth-sensitive magneto-optical Kerr effect. The SEMPA images confirm that the interfacial ferromagnetism coexisting with the antiferromagnetic phase inside the film is an intrinsic property of the FeRh(001) surface. Furthermore, the SEMPA data display a reduction of the in-plane magnetization occuring well above the phase transition temperature which, thus, is not related to the volume expansion at the phase transition. This observation is interpreted as a spin reorientation of the surfacemagnetization for which we propose a possible mechanism based on temperature-dependent tetragonal distortion due to different thermal expansion coefficients of MgO and FeRh

Hydrogen production on iron-magnesium oxide in the high-temperature water-gas shift reaction

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Biomonitoring of heavy metal pollution using the brown seaweed Ericaria Selaginoides along the Atlantic coast of Morocco

Increased pollution in the coastal areas may cause changes in the biodiversity of marine organisms depending upon their physiological capacity and resilience to thrive under stressing environmental conditions. The present research evaluates the heavy metals pollution degree of coastal waters using the macroalgae Ericaria selaginoides as bioindicator along the Atlantic coast of Morocco. Eight stations were chosen: two located near Eljadida city, three nearby Safi city and three around the city of Essaouira. Results showed that the heavy metal content in the thalli of E. selaginoides, in seawater and sediment varied seasonally. At the same time, it was negatively correlated with algal biodiversity onsite. However, the Chemical Oxygen Demand was significantly higher at the polluted station S5 than at other stations, while Dissolved Oxygen and Biological Oxygen Demand were lower. E. selaginoides accumulated metals in the following order Fe > Zn > Mn > Cu > Ni > Pb > Cr > Cd. In conclusion, E. selaginoides is overall more resilient to heavy metal pollution than other marine organisms in the Atlantic coast of Morocco, as indicated by substantially elevated concentrations of heavy metals in some sites. Our results support that E. selaginoides would be a suitable bioindicator for monitoring of heavy metals in polluted coastal areas

Évaluation de l’IRM cardiaque dans le suivi des patients ayant une hypertension artérielle pulmonaire (EVITA). IRM cardiaque dans le suivi de l’hypertension artérielle pulmonaire

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