26 research outputs found

    Deformation der karbonatischen Espanola-Formation im zentralen Teil der Sudbury-Impaktstruktur, Kanada

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    Archaische Granitoide und palĂ€oproterozoische Metasedimente der Huronian Supergroup werden von dem schĂŒsselförmigen und partiell erodierten 1.85 Ga alten Impaktschmelzkomplex der Sudbury-Impaktstruktur ĂŒberlagert. Huronische Metasedimente und deren basaler Kontakt zum granitoiden Grundgebirge stehen in einer Entfernung bis zu 15km von dem lagigen Komplex und um diesen herum steil. Obwohl diese Steilstellung durch die Bildung eines impakt-induzierten Zentralberges erklĂ€rt werden kann, ist unklar, ob orogene Verformung vor dem Impakt an der Steilstellung beteiligt war. Um hierĂŒber Aufschluss zu gewinnen, wurden die basalen Huronischen Einheiten, insbesondere die karbonatische Espanola Formation und deren benachbarte Metakonglomerate und Metasandsteine, nordöstlich des Impaktschmelzkomplexes strukturell untersucht. Aufgrund er NĂ€he der metasedimentĂ€ren Einheiten zu dem 2,5km mĂ€chtigen Schmelzkomplex wurde daher auch dessen möglicher thermischer Einfluss auf die Metasedimente untersucht...conferenc

    Deformation mechanisms in the eastern Sudbury Igneous Complex, Canada: Evidence for meteorite impact into an active orogen

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    The 1.85 Ga Sudbury Igneous Complex (SIC) in central Ontario is now widely considered to be the erosional remnant of a deformed paleo-horizontal impact melt sheet, about 2.5 km in thickness. Deformed impact melt breccias of the Onaping Formation and postimpact metasedimentary rocks overlie the layered SIC, which in turn rests on shocked Archean basement and Paleoproterozoic cover rocks. The main mass of the Igneous Complex is subdivided from top to bottom into granophyre, quartz-gabbro and norite layers. Previous workers considered noncylindrical folding and NW-directed reverse faulting as the main structural processes that formed the asymmetric, syn-formal geometry of the SIC apparent in map view and seismic section. Structural studies support this model in the southern part of the impact structure, where greenschist-facies metamorphic tectonites of the South Range Shear Zone (SRSZ) accomplished structural uplift of the southern SIC by NW-directed reverse shearing. However, little evidence for pervasive ductile strain has been reported from the weakly metamorphosed eastern part of the SIC, the East Range, which is characterised by steep basal dips and maximal curvature in plan view. The objective of this study is to assess the structural inventory of the East Range in terms of post-emplacement deformation mechanisms. Our interpretation is based on published and newly acquired structural data. Planar mineral shape fabrics of cumulate plagioclase and pyroxene are developed in the intermediate quartz-gabbro and lower norite layers of the southern East Range SIC. Microstructures show little intracrystalline deformation in quartz. Euhedral cumulate plagioclase retains an angular outline indicating magmatic mineral fabric development. This magmatic foliation is concordant to SIC contacts or large-scale discontinuities in their vicinity (Fig. 1). Magmatic fabrics are observed rarely in the northern portion of the East Range. Here, tectonic foliations and S–C fabrics are developed sporadically at, and concordant to, brittle structures striking N–S. A weak tectonic foliation defined by chlorite that replaces magmatic minerals is developed in the upper granophyric SIC of the NE-lobe that connects the SIC’s North and East Ranges via a 105° arc. This foliation grades into a shape-preferred orientation of primary, i.e., magmatic, mafic minerals observed in the lower granophyre and underlying layers of the SIC. Mineral fabrics observed in the NE-lobe SIC are concordant to metamorphic foliations developed in the overlying Onaping Formation breccias. Both foliations strike parallel to the NE-Lobe’s acute bisectrix and, thus, display an axial-planar geometry typical for fabrics formed in the core of a buckle fold (Fig. 1). Brittle structures including centimetre-scale shear-fractures to kilometre-scale faultzones are observed in the eastern SIC and its host rocks. Largescale faults striking N–S cut the NElobe’s eastern limb causing variable magnitudes of strike separation of SIC contacts. Centimetre- to metrescale, brittle faults and chlorite-filled brittle-ductile shear-zones occur pervasively in the eastern SIC, often causing centimetre-scale offset of markers. Microstructures from first-order fault-zones indicate deformation at, and below, greenschist-facies metamorphic conditions. The concordance of magmatic and tectonic mineral shape fabrics in the NElobe indicates progressive deformation of the SIC during cooling from the magmatic state to lower greenschistfacies metamorphic conditions. Synmagmatic deformation of the SIC suggests that it was emplaced during ongoing orogenic deformation. Furthermore, maximum principal stress directions inferred from inversion of faultslip data collected in the Onaping Formation are orthogonal to metamorphic foliation surfaces at the same localities. This points to a similar deformation regime in the Onaping Formation during ductile and brittle deformation. The concordance of magmatic, metamorphic and brittle fabrics is explained best by a single progressive deformation event that was active while the SIC cooled and solidified. The lack of pervasive ductile deformation fabrics in the East Range SIC can be explained by rapid cooling of the impact melt sheet (within 100–500 ka) with respect to natural tectonic strain rates. While the geometry of mineral fabrics in the study area is compatible with large-scale, non-cylindrical folding, the low levels of ductile deformation suggest that shape-change of the eastern SIC has been accomplished mainly by discontinuous deformation. This deformation mechanism may have accomplished bulk NW-SE shortening that was accommodated by reverse shearing within the SRSZ, resulting in large strike separations of SIC contacts observed in the western part of the impact structure. By contrast, the eastern SIC may have accomplished such shortening by brittleductile, non-cylindrical folding at the eastern terminus of the SRSZ. The complex post-impact deformation pattern of the central Sudbury Structure results from impact into an active orogen.conferenc

    A Scramjet Engine Model Including Effects of Precombustion Shocks and Dissociation

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76382/1/AIAA-2008-4619-101.pd

    31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

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    Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

    Evaluation of epiandrosterone as a long‐term marker of testosterone use

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    Identification and evaluation of long-term markers is crucial in prolonging the detection window for anabolic steroid abuse in sport. Recently, sulfoconjugated epiandrosterone was identified as a potential long-term marker for the abuse of certain endogenous anabolic agents, including testosterone, which continues to be widely used as a performance enhancing agent in sport. To evaluate the applicability of epiandrosterone sulfate as a marker for testosterone use, administration studies were conducted with multiple modes of testosterone administration - transdermal, intramuscular, and subcutaneous. A modified sample preparation method was used to collect both glucuronidated and sulfoconjugated analytes of interest. Carbon isotope ratio measurements from the administration studies are presented here. Epiandrosterone was less effective than the conventionally used target compounds for detection of the low dose application (transdermal gel). With intramuscular administration, epiandrosterone was more diagnostic than with transdermal administration, but it did not prolong the detection window more than the conventional target compounds. With subcutaneous administration, the doses administered to the subjects were varied and the effect on the epiandrosterone values was dependent on the magnitude of the dose administered. Epiandrosterone does not appear to be a useful marker in the detection of low dose testosterone administration. It is responsive to higher dose administration, but it does not provide an extension of the detection window relative to conventional target compounds

    Evaluation of epiandrosterone as a long-term marker of testosterone use

    Full text link
    Identification and evaluation of long-term markers is crucial in prolonging the detection window for anabolic steroid abuse in sport. Recently, sulfoconjugated epiandrosterone was identified as a potential long-term marker for the abuse of certain endogenous anabolic agents, including testosterone, which continues to be widely used as a performance enhancing agent in sport. To evaluate the applicability of epiandrosterone sulfate as a marker for testosterone use, administration studies were conducted with multiple modes of testosterone administration - transdermal, intramuscular, and subcutaneous. A modified sample preparation method was used to collect both glucuronidated and sulfoconjugated analytes of interest. Carbon isotope ratio measurements from the administration studies are presented here. Epiandrosterone was less effective than the conventionally used target compounds for detection of the low dose application (transdermal gel). With intramuscular administration, epiandrosterone was more diagnostic than with transdermal administration, but it did not prolong the detection window more than the conventional target compounds. With subcutaneous administration, the doses administered to the subjects were varied and the effect on the epiandrosterone values was dependent on the magnitude of the dose administered. Epiandrosterone does not appear to be a useful marker in the detection of low dose testosterone administration. It is responsive to higher dose administration, but it does not provide an extension of the detection window relative to conventional target compounds
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