49 research outputs found

    Dynamic pathway of the photoinduced phase transition of TbMnO3_3

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    We investigate the demagnetization dynamics of the cycloidal and sinusoidal phases of multiferroic TbMnO3_3 by means of time-resolved resonant soft x-ray diffraction following excitation by an optical pump. Using orthogonal linear x-ray polarizations, we suceeded in disentangling the response of the multiferroic cycloidal spin order from the sinusoidal antiferromagnetic order in the time domain. This enables us to identify the transient magnetic phase created by intense photoexcitation of the electrons and subsequent heating of the spin system on a picosecond timescale. The transient phase is shown to be a spin density wave, as in the adiabatic case, which nevertheless retains the wave vector of the cycloidal long range order. Two different pump photon energies, 1.55 eV and 3.1 eV, lead to population of the conduction band predominantly via intersite dd-dd transitions or intrasite pp-dd transitions, respectively. We find that the nature of the optical excitation does not play an important role in determining the dynamics of magnetic order melting. Further, we observe that the orbital reconstruction, which is induced by the spin ordering, disappears on a timescale comparable to that of the cycloidal order, attesting to a direct coupling between magnetic and orbital orders. Our observations are discussed in the context of recent theoretical models of demagnetization dynamics in strongly correlated systems, revealing the potential of this type of measurement as a benchmark for such complex theoretical studies

    Completeness of tuberculosis case notifications in Germany in 2013–2017: first results of an inventory study

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    Background Evaluating the completeness of tuberculosis (TB) notification data is important for monitoring of TB surveillance systems. We conducted an inventory study to calculate TB underreporting in Germany in 2013–2017. Methods Acquisition of two pseudonymized case-based data sources (national TB notification data and antibiotic resistance surveillance data) was followed by two-source Capture-recapture (CRC) analysis, as case-based data from a third source was unavailable. Aggregated data on consumption of a key anti-TB drug (pyrazinamide [PZA]) was compared to an estimated need for PZA based on TB notification data to obtain an independent underreporting estimation. Additionally, notified TB incidence was compared to TB rate in an aggregated health insurance fund dataset. Results CRC and PZA-based approaches indicated that between 93 and 97% (CRC) and between 91 and 95% (PZA) of estimated cases were captured in the national TB notification data in the years 2013–2017. Insurance fund dataset did not indicate TB underreporting on the national level in 2017. Conclusions Our results suggest that more than 90% of estimated TB cases are captured within the German TB surveillance system, and accordingly the TB notification rate is likely a good proxy of the diagnosed TB incidence rate. An increase in underreporting and discrepancies however should be further investigated.Peer Reviewe

    Vollständigkeit der Tuberkulose-Meldungen in Deutschland in den Jahren 2013 – 2017: Ergebnisse einer Inventurstudie

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    Für die Evaluation der Qualität von Tuberkulose-Meldesystemen ist die Bewertung der Vollständigkeit der Meldedaten von zentraler Bedeutung, da diese die Basis für eine aussagekräftige Tuberkulose-Surveillance und daraus abgeleitete Maßnahmen sind. Wie das Epidemiologische Bulletin 11/2021 beschreibt, wurde am Robert-Koch-Institut für den Zeitraum 2013-17 eine Inventarstudie zur Schätzung der Tuberkulose-Untererfassung in Deutschland durchgeführt. Das Ergebnis: mit einer Erfassungsquote von über 90% ist die Tuberkulose-Melderate trotz eines leichten Rückgangs innerhalb des untersuchten Zeitraums ein guter Näherungswert für die tatsächliche Tuberkulose-Inzidenz

    Novel Multifunctional Materials Based on Oxide Thin Films and Artificial Heteroepitaxial Multilayers

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    Transition metal oxides show fascinating physical properties such as high temperature superconductivity, ferro- and antiferromagnetism, ferroelectricity or even multiferroicity. The enormous progress in oxide thin film technology allows us to integrate these materials with semiconducting, normal conducting, dielectric or non-linear optical oxides in complex oxide heterostructures, providing the basis for novel multi-functional materials and various device applications. Here, we report on the combination of ferromagnetic, semiconducting, metallic, and dielectric materials properties in thin films and artificial heterostructures using laser molecular beam epitaxy. We discuss the fabrication and characterization of oxide-based ferromagnetic tunnel junctions, transition metal-doped semiconductors, intrinsic multiferroics, and artificial ferroelectric/ferromagetic heterostructures - the latter allow for the detailed study of strain effects, forming the basis of spin-mechanics. For characterization we use X-ray diffraction, SQUID magnetometry, magnetotransport measurements, and advanced methods of transmission electron microscopy with the goal to correlate macroscopic physical properties with the microstructure of the thin films and heterostructures.Comment: 21 pages, 21 figures (2 figures added, typos corrected

    Three-Dimensional In Vivo Imaging of the Murine Liver: A Micro-Computed Tomography-Based Anatomical Study

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    Various murine models are currently used to study acute and chronic pathological processes of the liver, and the efficacy of novel therapeutic regimens. The increasing availability of high-resolution small animal imaging modalities presents researchers with the opportunity to precisely identify and describe pathological processes of the liver. To meet the demands, the objective of this study was to provide a three-dimensional illustration of the macroscopic anatomical location of the murine liver lobes and hepatic vessels using small animal imaging modalities. We analysed micro-CT images of the murine liver by integrating additional information from the published literature to develop comprehensive illustrations of the macroscopic anatomical features of the murine liver and hepatic vasculature. As a result, we provide updated three-dimensional illustrations of the macroscopic anatomy of the murine liver and hepatic vessels using micro-CT. The information presented here provides researchers working in the field of experimental liver disease with a comprehensive, easily accessable overview of the macroscopic anatomy of the murine liver

    Minimally Invasive Monitoring of Chronic Central Venous Catheter Patency in Mice Using Digital Subtraction Angiography (DSA)

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    Repetitive administration of medication or contrast agents is frequently performed in mice. The introduction of vascular access mini-ports (VAMP) for mice allows long-term vascular catheterization, hereby eliminating the need for repeated vessel puncture. With catheter occlusion being the most commonly reported complication of chronic jugular vein catheterization, we tested whether digital subtraction angiography (DSA) can be utilized to evaluate VAMP patency in mice.Twenty-three mice underwent catheterization of the jugular vein and subcutaneous implantation of a VAMP. The VAMP was flushed every second day with 50 μL of heparinized saline solution (25 IU/ml). DSA was performed during injection of 100 μL of an iodine based contrast agent using an industrial X-ray inspection system intraoperatively, as well as 7±2 and 14±2 days post implantation.DSA allowed localization of catheter tip position, to rule out dislocation, kinking or occlusion of a microcatheter, and to evaluate parent vessel patency. In addition, we observed different ante- and retrograde collateral flow patterns in case of jugular vein occlusion. More exactly, 30% of animals showed parent vessel occlusion after 7±2 days in our setting. At this time point, nevertheless, all VAMPs verified intravascular contrast administration. After 14±2 days, intravascular contrast injection was verified in 70% of the implanted VAMPs, whereas at this point of time 5 animals had died or were sacrificed and in 2 mice parent vessel occlusion hampered intravascular contrast injection. Notably, no occlusion of the catheter itself was observed.From our observations we conclude DSA to be a fast and valuable minimally invasive tool for investigation of catheter and parent vessel patency and for anatomical studies of collateral blood flow in animals as small as mice

    Biologically based design of an actuator system for a knee–ankle–foot orthosis

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    Knee–ankle–foot orthosis are systems used to restore human gait, providing stability during stance phase. A concept of actuator for knee–ankle–foot orthosis was developed based on biomechanical data. The actuator is conceived to provide mechanical means to reproduce the normal kinematics during human gait at joint level. Behaviour of the joints of the lower limb was approximated by elastic means and an actuator for each joint was designed and constructed. The rationale of the design process is presented, considering the functional aspects and aiming at a lightweight solution with low power demand. Tests performed with one patient suffering from post-poliomyelitis syndrome are presented and evidence of functional compensation during stance and swing phases with the proposed solution is given.The work presented in this paper has been partially funded through Grant IST-2001-37751 of the European Commission. The authors thank Ossur hf and Roessingh Research and Development for their contributions in materials and experimentation. The work presented in this paper has been partially funded by the European Commission.Peer reviewe

    Study of hydrated phases present in calcined paper sludge (metakaolinite)/saturated CaO dissolution system cured at 40 °C and 28 days of reaction

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    [EN] The present research is a part of an experimental study about obtaining recycled metakaolinite from a Spanish paper sludge waste as complementary cementing material. The mineral phases formation from paper sludge calcined at different temperatures (700, 750 and 800 °C) and two times of stay in the furnace (2 and 5 h) mixed with saturated lime dissolution are obtained mineral phases: C-S-H gel, stratlingite, tobermorite, hydrotalcite. The C-S-H gels generated in the first stages lose crystallinity and filled the existing holes between stratlingite and hydrotalcite. The different mineral evolves according to their stability fields toward crystalline aggregates more compact where the gels fill hollow.Peer reviewe
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