201 research outputs found

    Effect of Fe content on atomic and electronic structure of complex oxides Sr Ti,Fe O3 delta

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    Two series of SrTi1 xFexO3 amp; 948; STFO powders with different Fe content produced by two different methods, solid state reaction or modified Pechini synthesis, have been investigated by soft X ray absorption spectroscopy. The O1s K , Fe2p L2,3 and Ti2p L2,3 absorption spectra of STFO powders were analyzed. Partial substitution of Ti by Fe atoms in SrTiO3 were found to cause asymmetric distortion of TiO6 octahedrons which may violate the cubic symmetry of STFO. It was established that the distortion of TiO6 octahedrons increases with increasing Fe content. The joint analysis of the STFO spectra along with the reference compounds points to the presence mainly of Fe3 states in octahedral environment at small concentration of Fe atoms along with essentially smaller content of Fe4 states in octahedral environment where the latter contribution increases with increasing Fe content. Also a presence of Fe3 states in tetrahedral environment with Fe content higher than 50 is traced. A certain amount of Fe2 ions in an octahedral environment was also found in the STFO compound prepared by spray pyrolysis with Fe content higher than 75 . The O1s K absorption spectra point to increase in oxygen vacancy concentration with increasing Fe content. The lowest degree of structure distortions was traced in STFO35. Hence, the STFO35 compound seems to be mostly appropriate for technical application

    Impairment of germline transmission after blastocyst injection with murine embryonic stem cells cultured with mouse hepatitis virus and mouse minute virus

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    The aim of this study was to determine the susceptibility of murine embryonic stem (mESCs) to mouse hepatitis virus (MHV-A59) and mouse minute virus (MMVp) and the effect of these viruses on germline transmission (GLT) and the serological status of recipients and pups. When recipients received 10 blastocysts, each injected with 100 TCID50 MHV-A59, three out of five recipients and four out of 14 pups from three litters became seropositive. When blastocysts were injected with 10−5 TCID50 MMVp, all four recipients and 14 pups from four litters remained seronegative. The mESCs replicated MHV-A59 but not MMVp, MHV-A59 being cytolytic for mESCs. Exposure of mESCs to the viruses over four to five passages but not for 6 h affected GLT. Recipients were seropositive for MHV-A59 but not for MMVp when mESCs were cultured with the virus over four or five passages. The data show that GLT is affected by virus-contaminated mESCs

    The Forward Physics Facility: Sites, Experiments, and Physics Potential

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    The Forward Physics Facility (FPF) is a proposal to create a cavern with thespace and infrastructure to support a suite of far-forward experiments at theLarge Hadron Collider during the High Luminosity era. Located along the beamcollision axis and shielded from the interaction point by at least 100 m ofconcrete and rock, the FPF will house experiments that will detect particlesoutside the acceptance of the existing large LHC experiments and will observerare and exotic processes in an extremely low-background environment. In thiswork, we summarize the current status of plans for the FPF, including recentprogress in civil engineering in identifying promising sites for the FPF andthe experiments currently envisioned to realize the FPF's physics potential. Wethen review the many Standard Model and new physics topics that will beadvanced by the FPF, including searches for long-lived particles, probes ofdark matter and dark sectors, high-statistics studies of TeV neutrinos of allthree flavors, aspects of perturbative and non-perturbative QCD, andhigh-energy astroparticle physics.<br

    The Forward Physics Facility at the High-Luminosity LHC

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    High energy collisions at the High-Luminosity Large Hadron Collider (LHC) produce a large number of particles along the beam collision axis, outside of the acceptance of existing LHC experiments. The proposed Forward Physics Facility (FPF), to be located several hundred meters from the ATLAS interaction point and shielded by concrete and rock, will host a suite of experiments to probe standard model (SM) processes and search for physics beyond the standard model (BSM). In this report, we review the status of the civil engineering plans and the experiments to explore the diverse physics signals that can be uniquely probed in the forward region. FPF experiments will be sensitive to a broad range of BSM physics through searches for new particle scattering or decay signatures and deviations from SM expectations in high statistics analyses with TeV neutrinos in this low-background environment. High statistics neutrino detection will also provide valuable data for fundamental topics in perturbative and non-perturbative QCD and in weak interactions. Experiments at the FPF will enable synergies between forward particle production at the LHC and astroparticle physics to be exploited. We report here on these physics topics, on infrastructure, detector, and simulation studies, and on future directions to realize the FPF's physics potential

    Prediction of overall survival for patients with metastatic castration-resistant prostate cancer : development of a prognostic model through a crowdsourced challenge with open clinical trial data

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    Background Improvements to prognostic models in metastatic castration-resistant prostate cancer have the potential to augment clinical trial design and guide treatment strategies. In partnership with Project Data Sphere, a not-for-profit initiative allowing data from cancer clinical trials to be shared broadly with researchers, we designed an open-data, crowdsourced, DREAM (Dialogue for Reverse Engineering Assessments and Methods) challenge to not only identify a better prognostic model for prediction of survival in patients with metastatic castration-resistant prostate cancer but also engage a community of international data scientists to study this disease. Methods Data from the comparator arms of four phase 3 clinical trials in first-line metastatic castration-resistant prostate cancer were obtained from Project Data Sphere, comprising 476 patients treated with docetaxel and prednisone from the ASCENT2 trial, 526 patients treated with docetaxel, prednisone, and placebo in the MAINSAIL trial, 598 patients treated with docetaxel, prednisone or prednisolone, and placebo in the VENICE trial, and 470 patients treated with docetaxel and placebo in the ENTHUSE 33 trial. Datasets consisting of more than 150 clinical variables were curated centrally, including demographics, laboratory values, medical history, lesion sites, and previous treatments. Data from ASCENT2, MAINSAIL, and VENICE were released publicly to be used as training data to predict the outcome of interest-namely, overall survival. Clinical data were also released for ENTHUSE 33, but data for outcome variables (overall survival and event status) were hidden from the challenge participants so that ENTHUSE 33 could be used for independent validation. Methods were evaluated using the integrated time-dependent area under the curve (iAUC). The reference model, based on eight clinical variables and a penalised Cox proportional-hazards model, was used to compare method performance. Further validation was done using data from a fifth trial-ENTHUSE M1-in which 266 patients with metastatic castration-resistant prostate cancer were treated with placebo alone. Findings 50 independent methods were developed to predict overall survival and were evaluated through the DREAM challenge. The top performer was based on an ensemble of penalised Cox regression models (ePCR), which uniquely identified predictive interaction effects with immune biomarkers and markers of hepatic and renal function. Overall, ePCR outperformed all other methods (iAUC 0.791; Bayes factor >5) and surpassed the reference model (iAUC 0.743; Bayes factor >20). Both the ePCR model and reference models stratified patients in the ENTHUSE 33 trial into high-risk and low-risk groups with significantly different overall survival (ePCR: hazard ratio 3.32, 95% CI 2.39-4.62, p Interpretation Novel prognostic factors were delineated, and the assessment of 50 methods developed by independent international teams establishes a benchmark for development of methods in the future. The results of this effort show that data-sharing, when combined with a crowdsourced challenge, is a robust and powerful framework to develop new prognostic models in advanced prostate cancer.Peer reviewe
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