676 research outputs found
Christoph Schlingensiefs analoge und digitale Selbst-Entwürfe: Das Tagebuch einer Krebserkrankung und der Schlingenblog
Eine grundlegende künstlerische Strategie von Regisseur und Künstler Christoph Schlingensief war die (vermeintliche) mediale Offenlegung des Subjekts. Der Beitrag untersucht Formen der Subjektivation in zwei verschiedenen Medien, im Tagebuch einer Krebserkrankung und Schlingensiefs Schlingenblog. Es scheint, als finde die Aushandlung des Subjekts zum einen im Modus der Offenheit und Autofiktion, zum anderen über den Modus der Sichtbarkeit und Öffentlichkeit statt. <br
Small-molecule lysophosphatidic acid receptor 5 (LPAR5) antagonists: versatile pharmacological tools to regulate inflammatory signaling in BV-2 microglia cells
Lysophosphatidic acid (LPA) species in the extracellular environment induce downstream signaling via six different G protein-coupled receptors (LPAR1-6). These signaling cascades are essential for normal brain development and function of the nervous system. However, in response to acute or chronic central nervous system (CNS) damage, LPA levels increase and aberrant signaling events can counteract brain function. Under neuro-inflammatory conditions signaling along the LPA/LPAR5 axis induces a potentially neurotoxic microglia phenotype indicating the need for new pharmacological intervention strategies. Therefore, we compared the effects of two novel small-molecule LPAR5 antagonists on LPA-induced polarization parameters of the BV-2 microglia cell line. AS2717638 is a selective piperidine-based LPAR5 antagonist (IC(50) 0.038 μM) while compound 3 is a diphenylpyrazole derivative with an IC(50) concentration of 0.7 μM in BV-2 cells. Both antagonists compromised cell viability, however, at concentrations above their IC(50) concentrations. Both inhibitors blunted LPA-induced phosphorylation of STAT1 and STAT3, p65, and c-Jun and consequently reduced the secretion of pro-inflammatory cyto-/chemokines (IL-6, TNFα, IL-1β, CXCL10, CXCL2, and CCL5) at non-toxic concentrations. Both compounds modulated the expression of intracellular (COX-2 and Arg1) and plasma membrane-located (CD40, CD86, and CD206) polarization markers yet only AS2717638 attenuated the neurotoxic potential of LPA-activated BV-2 cell-conditioned medium towards CATH.a neurons. Our findings from the present in vitro study suggest that the two LPAR5 antagonists represent valuable pharmacological tools to interfere with LPA-induced pro-inflammatory signaling cascades in microglia
The AGeS2 (Awards for Geochronology Student research 2) Program: Supporting Community Geochronology Needs and Interdisciplinary Science
Geochronology is essential in the geosciences. It is used to resolve the durations and rates of earth processes, as well as test causative relationships among events. Such data are increasingly required to conduct cutting-edge, transformative, earth-science research. The growing need for geochronology is accompanied by strong demand to enhance the ability of labs to meet this pressure and to increase community awareness of how these data are produced and interpreted. For example, a 2015 National Science Foundation (NSF) report on opportunities and challenges for U.S. geochronology research noted: While there has never been a time when users have had greater access to geo-chronologic data, they remain, by and large, dissatisfied with the available style/ quantity/cost/efficiency (Harrison et al., 2015, p. 1). And the 2012 National Research Council NROES (New Research Opportunities in the Earth Sciences) report (Lay et al., 2012, p. 82) recommended: [NSF] EAR should explore new mechanisms for geochronology laboratories that will service the geochronology requirements of the broad suite of research opportunities while sustaining technical advances in methodologies. The AGeS (Awards for Geochronology Student research) program is one way that these calls are being answered
Experimental Realization of an Optical One-Way Barrier for Neutral Atoms
We demonstrate an asymmetric optical potential barrier for ultracold 87 Rb
atoms using laser light tuned near the D_2 optical transition. Such a one-way
barrier, where atoms impinging on one side are transmitted but reflected from
the other, is a realization of Maxwell's demon and has important implications
for cooling atoms and molecules not amenable to standard laser-cooling
techniques. In our experiment, atoms are confined to a far-detuned dipole trap
consisting of a single focused Gaussian beam, which is divided near the focus
by the barrier. The one-way barrier consists of two focused laser beams
oriented almost normal to the dipole-trap axis. The first beam is tuned to have
a red (blue) detuning from the F=1 -> F' (F=2 -> F') hyperfine transitions, and
thus presents a barrier only for atoms in the F=2 ground state, while letting
F=1 atoms pass. The second beam pumps the atoms to F=2 on the reflecting side
of the barrier, thus producing the asymmetry.Comment: 5 pages, 4 figures; includes changes to address referee comment
volumetric characterisation and correlation to established classification systems
Objective and sensitive assessment of cartilage repair outcomes lacks suitable
methods. This study investigated the feasibility of 3D ultrasound
biomicroscopy (UBM) to quantify cartilage repair outcomes volumetrically and
their correlation with established classification systems. 32 sheep underwent
bilateral treatment of a focal cartilage defect. One or two years post-
operatively the repair outcomes were assessed and scored macroscopically
(Outerbridge, ICRS-CRA), by magnetic resonance imaging (MRI, MOCART), and
histopathology (O'Driscoll, ICRS-I and ICRS-II). The UBM data were acquired
after MRI and used to reconstruct the shape of the initial cartilage layer,
enabling the estimation of the initial cartilage thickness and defect volume
as well as volumetric parameters for defect filling, repair tissue, bone loss
and bone overgrowth. The quantification of the repair outcomes revealed high
variations in the initial thickness of the cartilage layer, indicating the
need for cartilage thickness estimation before creating a defect. Furthermore,
highly significant correlations were found for the defect filling estimated
from UBM to the established classification systems. 3D visualisation of the
repair regions showed highly variable morphology within single samples. This
raises the question as to whether macroscopic, MRI and histopathological
scoring provide sufficient reliability. The biases of the individual methods
will be discussed within this context. UBM was shown to be a feasible tool to
evaluate cartilage repair outcomes, whereby the most important objective
parameter is the defect filling. Translation of UBM into arthroscopic or
transcutaneous ultrasound examinations would allow non-destructive and
objective follow-up of individual patients and better comparison between the
results of clinical trials
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Evaluating uncertainties in the calibration of isotopic reference materials and multi-element isotopic tracers (EARTHTIME Tracer Calibration Part II)
A statistical approach to evaluating uncertainties in the calibration of multi-element isotopic tracers has been developed and applied to determining the isotopic composition of mixed U-Pb (202Pb-205Pb-233U-235U) tracers used for accurate isotope dilution U-Pb geochronology. Our experiment, part of the EARTHTIME initiative, directly links the tracer calibration to first-principles measurements of mass and purity that are all traceable to SI units, thereby quantifying the accuracy and precision of U-Pb dates in absolute time. The calibration incorporates new more accurate and precise purity measurements for a number of commonly used Pb and U reference materials, and requires inter-relating their isotopic compositions and uncertainties. Similar methods can be used for other isotope systems that utilize multiple isotopic standards for calibration purposes. We also detail the inter-calibration of three publicly available U-Pb gravimetric solutions, which can be used to bring the same first-principles traceability to in-house U-Pb tracers from other laboratories. Accounting for uncertainty correlations in the tracer isotope ratios yields a tracer calibration contribution to the relative uncertainty of a 206Pb/238U date that is only half of the relative uncertainty in the 235U/205Pb ratio of the tracer, which was historically used to approximate the tracer related uncertainty contribution to 206Pb/238U dates. The tracer uncertainty contribution to 206Pb/238U dates has in this way been reduced to <300 ppm when using the EARTHTIME and similarly calibrated tracers
Isotopic composition (238U/235U) of some commonly used uranium reference materials
We have determined 238U/235U ratios for a suite of commonly used natural (CRM 112a, SRM 950a, and HU-1) and synthetic (IRMM 184 and CRM U500) uranium reference materials by thermal ionisation mass-spectrometry (TIMS) using the IRMM 3636 233U-236U double spike to accurately correct for mass fractionation. Total uncertainty on the 238U/235U determinations is estimated to be < 0.02% (2σ). These natural 238U/235U values are different from the widely used ‘consensus’ value (137.88), with each standard having lower 238U/235U values by up to 0.08%. The 238U/235U ratio determined for CRM U500 and IRMM 184 are within error of their certified values; however, the total uncertainty for CRM U500 is substantially reduced (from 0.1% to 0.02%). These reference materials are commonly used to assess mass spectrometer performance and accuracy, calibrate isotope tracers employed in U, U-Th and U-Pb isotopic studies, and as a reference for terrestrial and meteoritic 238U/235U variations. These new 238U/235U values will thus provide greater accuracy and reduced uncertainty for a wide variety of isotopic determinations
Physical activity to improve cognition in older adults: can physical activity programs enriched with cognitive challenges enhance the effects? A systematic review and meta-analysis
: EPHPP quality rating scores (DOCX 38 kb
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