Mechanisms controlling CO2 and CH4 production in wetlands are central to understanding carbon cycling and greenhouse gas exchange. However, the volatility of these respiration products complicates ...quantifying their rates of production in the field. Attempts to circumvent the challenges through closed system incubations, from which gases cannot escape, have been used to investigate bulk in situ geochemistry. Efforts towards mapping mechanistic linkages between geochemistry and microbiology have raised concern regarding sampling and incubation-induced perturbations. Microorganisms are impacted by oxygen exposure, increased temperatures and accumulation of metabolic products during handling, storage, and incubation. We probed the extent of these perturbations, and their influence on incubation results, using high-resolution geochemical and microbial gene-based community profiling of anaerobically incubated material from three wetland habitats across a permafrost peatland. We compared the original field samples to the material anaerobically incubated over 50 days. Bulk geochemistry and phylum-level microbiota in incubations largely reflected field observations, but divergence between field and incubations occurred in both geochemistry and lineage-level microbial composition when examined at closer resolution. Despite the changes in representative lineages over time, inferred metabolic function with regards to carbon cycling largely reproduced field results suggesting functional consistency. Habitat differences among the source materials remained the largest driver of variation in geochemical and microbial differences among the samples in both incubations and field results. While incubations may have limited usefulness for identifying specific mechanisms, they remain a viable tool for probing bulk-scale questions related to anaerobic C cycling, including CO2 and CH4 dynamics.
Low gain avalanche detectors can measure charged particle fluences with high speed and spatial precision, and are a promising technology for radiation monitoring and dosimetry. A detector has been ...tested in a medical linac where single particles were observed with a time resolution of 50 ps. The integrated response is similar to a standard ionising chamber but with a spatial precision twenty times finer, and a temporal precision over 100 million times better, with the capability to measure the charge deposited by a single linac pulse. The unprecedented resolving power allows the structure of the ∼3 μs linac pulses to be viewed and the 350 ps sub-pulses in the train to be observed.
Resistive switching oxides are investigated at great length as promising candidates for the next generation of non-volatile memories. It is generally assumed that defects have a strong impact on the ...resistive switching properties of transition metal oxides. However, the correlation between different types of defect structures and the switching properties is still elusive. We deposited single-crystalline SrTiO3thin films with various cation stoichiometry by pulsed laser deposition to investigate the stoichiometry related and therefore defect dependent influence on the resistive switching properties. This letter will reveal the differences in initial states, forming steps, switching characteristics as well as retention times taking into account both point defects and extended defects. We then propose an explanation on the basis of oxygen vacancy generation and redistribution to elucidate the dependence of the resistive switching properties on the cation stoichiometry dependent defect structure.
Background: Patients with rheumatoid arthritis or polymyositis treated with methotrexate (MTX) develop Epstein–Barr virus (EBV)–positive lymphomas more frequently than patients treated with other, ...equally immunosuppressive regimens. Here we determined whether MTX, in contrast to other commonly used medications for rheumatoid arthritis or polymyositis, is unique in its ability to induce the release of infectious EBV from latently infected cells. Methods: The effect of MTX and other immunosuppressant drugs on EBV replication in vitro was assessed using latently infected EBV-positive lymphoblastoid and gastric carcinoma cell lines. Inhibitors of signal transduction pathways were used to define requirements for induction of lytic infection. Drug effects on transcription of the two EBV immediate-early promoters (BRLF1 and BZLF1) and on promoter constructs lacking cis-acting sequences required for activation by other effectors was examined using reporter gene assays. EBV viral load in rheumatoid arthritis and polymyositis patients receiving MTX was compared with that in patients receiving other immunosuppressive medications. Statistical tests were two-sided. Results: MTX activated the release of infectious EBV from latently infected cell lines in vitro, and MTX treatment was associated with activation of the two viral immediate-early promoters in reporter gene assays. Induction of lytic EBV infection by MTX required the p38 MAP kinase, PI3 kinase, and MEK pathways and specific cis-acting motifs in the two viral immediate-early promoters. Patients treated with MTX-containing regimens had statistically significantly higher mean EBV loads in their blood than patients treated with immunosuppressing regimens that did not include MTX (40 EBV copies per 106 cellular genomes versus 5.1 copies; geometric mean fold difference in copies = 10.8, 95%, confidence interval = 3.0 to 38; P = .011). Conclusion: MTX may promote EBV-positive lymphomas in rheumatoid arthritis and polymyositis patients by its immunosuppressive properties as well as by reactivating latent EBV.
Single crystals of Mott-Hubbard insulator LaVO3 exhibit spin and orbital ordering along with a structural change below ≈140 K. The occurrence of orbital ordering in epitaxial LaVO3 films has, ...however, been little investigated. By temperature-dependent Raman scattering spectroscopy, we probed and evidenced the transition to orbital ordering in epitaxial LaVO3 film samples fabricated by pulsed-laser deposition. This opens up the possibility to explore the influence of different epitaxial strain (compressive vs. tensile) and of epitaxy-induced distortions of oxygen octahedra on the orbital ordering, in epitaxial perovskite vanadate films.
The European X-ray Free Electron Laser (XFEL.EU) is an international research facility presently under construction in the area of Hamburg, Germany, which will start its operation at the end of 2016 ...1. The superconducting linear accelerator of the facility will deliver electron bunches with an energy of up to 17.5 GeV, arranged in trains of typically 2700 bunches at a repetition rate of 4.5 MHz. Each train will be followed by a gap of 99.4 ms. Spatially coherent X-rays are generated from the electron bunches in a series of undulators based on the Self-Amplified Spontaneous Emission (SASE) process, in three photon beamlines extending over a length of up to 200 m. Each beamline serves two experiments with different scientific goals. PUBLICATION ABSTRACT
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