Thermodynamics and transport properties of the ferromagnetic metal SrRuO3 and the frustrated magnet Cs3Fe2Br9

In this thesis, the ferromagnetic metal SrRuO3 and the frustrated antiferromagnet Cs3Fe2Br9 are investigated. New high-quality single crystals of SrRuO3 grown with the floating-zone technique are used to study the critical phenomena at the ferromagnetic phase transition. A shape-memory effect is found below TC, which makes the material ferroelastic and thus multiferroic. Spin-orbit coupling yields spin-split bands and a Weyl point close to the Fermi energy acts as a magnetic monopole in momentum space, which causes an intrinsic anomalous Hall effect. Furthermore, the anomalous softening of the magnon gap and the stiffness can be described with the Hall conductivity, which makes the explanation via the Berry-curvature contribution conclusive. The new material Cs3Fe2Br9 consists of face-sharing Fe2Br9 bi-octahedra that are arranged in triangular layers stacked to form a hexagonal structure and orders antiferromagnetically. In contrast to isostructural classical spin systems that form a singlet ground state, the two S = 5/2 moments in each bi-octahedron are oriented parallel along c. The in-plane nearest-neighbor interaction overcompensates the antiferromagnetic dimer coupling. The antiferromagnetic ground state is substantially frustrated. For a magnetic field along the easy-axis, an extremely rich phase diagram with ten phases is found. Two phases host a fractional magnetization and one phase shows a ferroelectric polarization. The results are compared to analytical and numerical predictions for triangular and hexagonal lattices and related material

Real-time determination of laser beam quality by modal decomposition

We present a real-time method to determine the beam propagation ratio M2 of laser beams. The all-optical measurement of modal amplitudes yields M2 parameters conform to the ISO standard method. The experimental technique is simple and fast, which allows to investigate laser beams under conditions inaccessible to other methods.Comment: 8 pages, 4 figures, published in Optics Expres

Interplay of weak ferromagnetism, ferroelasticity and shape-memory effects in the spin-orbit coupled antiferromagnet K2_2ReCl6_6

The magnetic and structural phase transitions occurring in K$_2$ReCl$_6$ were studied by macroscopic and microscopic techniques. Structural phase transitions associated with rotations of the ReCl$_6$ octahedra lower the symmetry from cubic to monoclinic, form ferroelastic domains, and are visible in susceptibility, specific heat and thermal expansion measurements. In the antiferromagnetically ordered state slightly below $T_{\rm N}$=12\,K these domains can be rearranged by a magnetic field inducing a relative elongation of the polydomain crystal parallel to the field of 0.6\%. At zero field the magnetic structure in K$_2$ReCl$_6$ does not exhibit a weak ferromagnetic component, but at large magnetic field a distinct magnetic structure with a finite weak ferromagnetic component is stabilized. High magnetic fields rearrange the domains in the crystal to align the weak ferromagnetic moment parallel to the field. The altered domain structure with the crystal elongation is abruptly suppressed at lower temperature but persists upon heating to well above $T_{\rm N}$. However, heating above the lowest structural phase transition and successive cooling restore the initial shape, i.e. a magnetic shape memory effect.Comment: 11 pages, 9 figure

Assessment of Confounding Factors Affecting the Tumor Markers SMRP, CA125, and CYFRA21-1 in Serum

The purpose of this analysis was to evaluate if serum levels of potential tumor markers for the diagnosis of malignant mesothelioma and lung cancer are affected by confounding factors in a surveillance cohort of workers formerly exposed to asbestos. SMRP, CA125, and CYFRA21-1 concentrations were determined in about 1,700 serum samples from 627 workers formerly exposed to asbestos. The impact of factors that could modify the concentrations of the tumor markers was examined with linear mixed models. SMRP values increased with age 1.02-fold (95% CI 1.01–1.03) and serum creatinine concentration 1.32-fold (95% CI 1.20–1.45). Levels differed by study centers and were higher after 40 years of asbestos exposure. CA125 levels increased with longer storage of the samples. CYFRA21-1 values correlated with age 1.02-fold (95% CI 1.01–1.02), serum creatinine 1.21-fold (95% CI 1.14–1.30) and varied by study centers due to differences in sample handling. Tumor marker concentrations are influenced by subject-related factors, sample handling, and storage. These factors need to be taken into account in screening routine

Assessment of mRNA and microRNA Stabilization in Peripheral Human Blood for Multicenter Studies and Biobanks

In this study we evaluate the suitability of two methods of RNA conservation in blood samples, PAXgene and RNAlater, in combination with variable shipping conditions for their application in multicenter studies and biobanking. RNA yield, integrity, and purity as well as levels of selected mRNA and microRNA species were analyzed in peripheral human blood samples stabilized by PAXgene or RNAlater and shipped on dry ice or at ambient temperatures from the study centers to the central analysis laboratory. Both examined systems were clearly appropriate for RNA stabilization in human blood independently of the shipping conditions. The isolated RNA is characterized by good quantity and quality and well suited for downstream applications like quantitative RT-PCR analysis of mRNA and microRNA. Superior yield and integrity values were received using RNAlater. It would be reasonable to consider the production and approval of blood collection tubes prefilled with RNAlater to facilitate the use of this excellent RNA stabilization system in large studies

Bibliografía

Se reseñan los siguientes libros: * Etienne Gilson, Jean Duns Scot (Introduction a ses positions fondamentales), París, Vrin, 1952. * Ludwig Landgrebe, Phanomenology und Metaphysik. Editorial Marion von Schroeder, Hamburg 1949. * Aloys Wenzl, Materie und Leben, Editorial Curt E. Schwab, Stuttgart 1949. * Ludwig Klages, Los fundamentos de la Caracterología, traducción de Blas A. Sosa. Editorial Paidós, Buenos Aires, 1953. * Raymond Aron, Sociólogos alemanes contemporáneos, traducción por Carlos A. Fayard, Editorial Paidós, Buenos Aires. * Benedetto Croce, Ética y Política, traducción por Enrique Pezzoni, Editorial Imán, Buenos Aires, 1952. * J. G. Flügel, Psicoanálisis de la familia, traducción por M. L. Ferrando de Cabañera, Editorial Paidós, Buenos Aires, 1953. * John Dewey, El hombre y sus problemas, traducción de Eduardo Prieto. Editorial Paidós, Buenos Aires, 1952. * Rodolfo Mondolfo, El infinito en el pensamiento de la Antigüedad clásica, traducción por F. González Ríos, Editorial Imán, Buenos Aires, 1952. * Louis Gardet, Expériences mystiques en terres non chretiennes. (Collection "Sagesse et Cultures". Edit. Alsatia. París 1953). * W. Windelband, Historia de la filosofía moderna, traducción del alemán por Elsa Tabernig, 2 vols., Nova, Buenos Aires, 1952.Facultad de Humanidades y Ciencias de la Educación (FAHCE

Bibliografía

Se reseñan los siguientes libros: * Etienne Gilson, Jean Duns Scot (Introduction a ses positions fondamentales), París, Vrin, 1952. * Ludwig Landgrebe, Phanomenology und Metaphysik. Editorial Marion von Schroeder, Hamburg 1949. * Aloys Wenzl, Materie und Leben, Editorial Curt E. Schwab, Stuttgart 1949. * Ludwig Klages, Los fundamentos de la Caracterología, traducción de Blas A. Sosa. Editorial Paidós, Buenos Aires, 1953. * Raymond Aron, Sociólogos alemanes contemporáneos, traducción por Carlos A. Fayard, Editorial Paidós, Buenos Aires. * Benedetto Croce, Ética y Política, traducción por Enrique Pezzoni, Editorial Imán, Buenos Aires, 1952. * J. G. Flügel, Psicoanálisis de la familia, traducción por M. L. Ferrando de Cabañera, Editorial Paidós, Buenos Aires, 1953. * John Dewey, El hombre y sus problemas, traducción de Eduardo Prieto. Editorial Paidós, Buenos Aires, 1952. * Rodolfo Mondolfo, El infinito en el pensamiento de la Antigüedad clásica, traducción por F. González Ríos, Editorial Imán, Buenos Aires, 1952. * Louis Gardet, Expériences mystiques en terres non chretiennes. (Collection "Sagesse et Cultures". Edit. Alsatia. París 1953). * W. Windelband, Historia de la filosofía moderna, traducción del alemán por Elsa Tabernig, 2 vols., Nova, Buenos Aires, 1952.Facultad de Humanidades y Ciencias de la Educación (FAHCE

Everolimus after failure of one prior VEGF-targeted therapy in metastatic renal cell carcinoma : Final results of the MARC-2 trial

MARC-2, a prospective, multicenter phase IV trial, aimed to investigate clinical outcomes in patients with metastatic renal cell carcinoma (mRCC) treated with everolimus after failure of one initial vascular endothelial growth factor receptor tyrosine kinase inhibitor (VEGFR-TKI) therapy and to identify subgroups benefiting most, based on clinical characteristics and biomarkers. Patients with clear cell mRCC failing one initial VEGFR-TKI received everolimus until progression or unacceptable toxicity. Primary endpoint was 6-month progression-free survival rate (6moPFS). Secondary endpoints were overall response rate (ORR), PFS, overall survival (OS), and safety. Between 2011 and 2015, 63 patients were enrolled. Median age was 65.4 years (range 43.3-81.1). 6moPFS was 39.3% (95% confidence interval [CI], 27.0-51.3) overall, 54.4% (95% CI, 35.2-70.1) vs 23.7% (95% CI, 10.5-39.9) for patients aged ≥65 vs 25 vs ≤25 kg/m2. A Cox proportional hazards model confirmed a longer PFS for patients aged ≥65 years (hazard ratio [HR] 0.46; 95% CI, 0.26-0.80) and a longer OS for patients with BMI >25 kg/m2 (HR 0.36; 95% CI, 0.18-0.71). Median PFS and median OS were 3.8 months (95% CI, 3.2-6.2) and 16.8 months (95% CI, 14.3-24.3). ORR was 7.9% and disease control rate was 60.3%. No new safety signals emerged. Most common adverse events were stomatitis (31.7%), fatigue (31.7%), and anemia (30.2%). One patient died from treatment-related upper gastrointestinal hemorrhage. Everolimus remains a safe and effective treatment option for mRCC patients after one prior VEGFR-TKI therapy. Patients aged ≥65 years and patients with BMI >25 kg/m2 benefited most

Establishing a Large-Scale Field Experiment to Assess the Effects of Artificial Light at Night on Species and Food Webs

Artificial light at night (ALAN) is one of the most obvious hallmarks of human presence in an ecosystem. The rapidly increasing use of artificial light has fundamentally transformed nightscapes throughout most of the globe, although little is known about how ALAN impacts the biodiversity and food webs of illuminated ecosystems. We developed a large-scale experimental infrastructure to study the effects of ALAN on a light-naïve, natural riparian (i.e., terrestrial-aquatic) ecosystem. Twelve street lights (20 m apart) arranged in three rows parallel to an agricultural drainage ditch were installed on each of two sites located in a grassland ecosystem in northern Germany. A range of biotic, abiotic, and photometric data are collected regularly to study the short- and long-term effects of ALAN on behavior, species interactions, physiology, and species composition of communities. Here we describe the infrastructure setup and data collection methods, and characterize the study area including photometric measurements. None of the measured parameters differed significantly between sites in the period before illumination. Results of one short-term experiment, carried out with one site illuminated and the other acting as a control, demonstrate the attraction of ALAN by the immense and immediate increase of insect catches at the lit street lights. The experimental setup provides a unique platform for carrying out interdisciplinary research on sustainable lighting