441 research outputs found

    Measurement of Trace I-129 Concentrations in CsI Powder and Organic Liquid Scintillator with Accelerator Mass Spectrometry

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    Levels of trace radiopurity in active detector materials is a subject of major concern in low-background experiments. Procedures were devised to measure trace concentrations of I-129 in the inorganic salt CsI as well as in organic liquid scintillator with Accelerator Mass Spectrometry (AMS) which leads to improvement in sensitivities by several orders of magnitude over other methods. No evidence of their existence in these materials were observed. Limits of < 6 X 10^{-13} g/g and < 2.6 X 10^{-17} g/g on the contaminations of I-129 in CsI and liquid scintillator, respectively, were derived.These are the first results in a research program whose goals are to develop techniques to measure trace radioactivity in detector materials by AMS.Comment: Proceedings of 10th International Conference on Accelerator Mass Spectrometr

    Measurement of Ultra-Low Potassium Contaminations with Accelerator Mass Spectrometry

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    Levels of trace radiopurity in active detector materials is a subject of major concern in low-background experiments. Among the radio-isotopes, \k40 is one of the most abundant and yet whose signatures are difficult to reject. Procedures were devised to measure trace potassium concentrations in the inorganic salt CsI as well as in organic liquid scintillator (LS) with Accelerator Mass Spectrometry (AMS), giving, respectively, the \k40-contamination levels of ∌10−10\sim 10^{-10} and ∌10−13\sim 10^{-13} g/g. Measurement flexibilities and sensitivities are improved over conventional methods. The projected limiting sensitivities if no excess of potassium signals had been observed over background are 8×10−138 \times 10^{-13} g/g and 3×10−173 \times 10^{-17} g/g for the CsI and LS, respectively. Studies of the LS samples indicate that the radioactive contaminations come mainly in the dye solutes, while the base solvents are orders of magnitude cleaner. The work demonstrate the possibilities of measuring naturally-occurring isotopes with the AMS techniques.Comment: 18 pages, 4 figures, 3 table

    Deficiency of Th17 cells in hyper IgE syndrome due to mutations in STAT3

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    Hyper–immunoglobulin E syndrome (HIES) is a primary immune deficiency characterized by abnormal and devastating susceptibility to a narrow spectrum of infections, most commonly Staphylococcus aureus and Candida albicans. Recent investigations have identified mutations in STAT3 in the majority of HIES patients studied. Despite the identification of the genetic cause of HIES, the mechanisms underlying the pathological features of this disease remain to be elucidated. Here, we demonstrate a failure of CD4+ T cells harboring heterozygous STAT3 mutations to generate interleukin 17–secreting (i.e., T helper [Th]17) cells in vivo and in vitro due to a failure to express sufficient levels of the Th17-specific transcriptional regulator retinoid-related orphan receptor γt. Because Th17 cells are enriched for cells with specificities against fungal antigens, our results may explain the pattern of infection susceptibility characteristic of patients with HIES. Furthermore, they underscore the importance of Th17 responses in normal host defense against the common pathogens S. aureus and C. albicans

    ĐœĐœĐŸĐłĐŸŃ†Đ”ĐœŃ‚Ń€ĐŸĐČĐŸĐ” ĐžŃŃĐ»Đ”ĐŽĐŸĐČĐ°ĐœĐžĐ” ŃŃ„Ń„Đ”ĐșтоĐČĐœĐŸŃŃ‚Đž ĐœĐ”ĐŸĐ°ĐŽŃŠŃŽĐČĐ°ĐœŃ‚ĐœĐŸĐč тДрапОО ХАРОЄ/бДĐČĐ°Ń†ĐžĐ·ŃƒĐŒĐ°Đ± у ĐœĐ”ĐŸĐżĐ”Ń€Đ°Đ±Đ”Đ»ŃŒĐœŃ‹Ń… Đ±ĐŸĐ»ŃŒĐœŃ‹Ń… с ĐŒĐ”Ń‚Đ°ŃŃ‚Đ°Đ·Đ°ĐŒĐž ĐșĐŸĐ»ĐŸŃ€Đ”ĐșŃ‚Đ°Đ»ŃŒĐœĐŸĐłĐŸ раĐșĐ° ĐČ ĐżĐ”Ń‡Đ”ĐœĐž

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    ĐŸŃ€ĐŸĐ°ĐœĐ°Đ»ĐžĐ·ĐžŃ€ĐŸĐČĐ°ĐœŃ‹ Ń€Đ”Đ·ŃƒĐ»ŃŒŃ‚Đ°Ń‚Ń‹ ĐŒĐœĐŸĐłĐŸŃ†Đ”ĐœŃ‚Ń€ĐŸĐČĐŸĐłĐŸ ĐžŃŃĐ»Đ”ĐŽĐŸĐČĐ°ĐœĐžŃ II Ń„Đ°Đ·Ń‹, ĐČ ĐșĐŸŃ‚ĐŸŃ€ĐŸĐŒ ĐżĐŸĐșĐ°Đ·Đ°ĐœĐ° ŃŃ„Ń„Đ”ĐșтоĐČĐœĐŸŃŃ‚ŃŒ Đž Đ±Đ”Đ·ĐŸĐżĐ°ŃĐœĐŸŃŃ‚ŃŒ ĐșĐŸĐŒĐ±ĐžĐœĐ°Ń†ĐžĐž Ń€Đ”Đ¶ĐžĐŒĐ° CAPOX с бДĐČĐ°Ń†ĐžĐ·ŃƒĐŒĐ°Đ±ĐŸĐŒ про ĐœĐ”ĐŸĐ°ĐŽŃŠŃŽĐČĐ°ĐœŃ‚ĐœĐŸĐč тДрапОО ĐœĐ” ĐżĐŸĐŽĐ»Đ”Đ¶Đ°Ń‰ĐžŃ… Ń…ĐžŃ€ŃƒŃ€ĐłĐžŃ‡Đ”ŃĐșĐŸĐŒŃƒ Đ»Đ”Ń‡Đ”ĐœĐžŃŽ ĐżĐ°Ń†ĐžĐ”ĐœŃ‚ĐŸĐČ Ń ĐŒĐ”Ń‚Đ°ŃŃ‚Đ°Đ·Đ°ĐŒĐž ĐșĐŸĐ»ĐŸŃ€Đ”ĐșŃ‚Đ°Đ»ŃŒĐœĐŸĐłĐŸ раĐșĐ° ĐČ ĐżĐ”Ń‡Đ”ĐœĐž: рДзДĐșŃ‚Đ°Đ±Đ”Đ»ŃŒĐœĐŸŃŃ‚ŃŒ ĐżĐŸŃĐ»Đ”ĐŽĐœĐžŃ… была ĐŽĐŸŃŃ‚ĐžĐłĐœŃƒŃ‚Đ° ĐČ 44% ŃĐ»ŃƒŃ‡Đ°Đ”ĐČ, 12-ĐŒĐ”ŃŃŃ‡ĐœĐ°Ń ĐČыжОĐČĐ°Đ”ĐŒĐŸŃŃ‚ŃŒ: ĐŸĐ±Ń‰Đ°Ń – 96%, бДзрДцОЎОĐČĐœĐ°Ń – 50%. КлючДĐČŃ‹Đ” ŃĐ»ĐŸĐČĐ°: ĐșĐŸĐ»ĐŸŃ€Đ”ĐșŃ‚Đ°Đ»ŃŒĐœŃ‹Đč раĐș, ĐŒĐ”Ń‚Đ°ŃŃ‚Đ°Đ·Ń‹ ĐČ ĐżĐ”Ń‡Đ”ĐœĐž, бДĐČĐ°Ń†ĐžĐ·ŃƒĐŒĐ°Đ±, ĐșĐ°ĐżĐ”Ń†ĐžŃ‚Đ°Đ±ĐžĐœ, ĐŸĐșŃĐ°Đ»ĐžĐżĐ»Đ°Ń‚ĐžĐœ.The results of multicentre study of II phase are analyzed. The efficacy and safety of combined regimen CAPOX + bevacizumab in adjuvant therapy of patients not selected for upfront resection and with colorectal cancer metastasis in liver is demonstrated. The respectability was achieved in 44% of cases, 12-month survival, overall, survival 96%, without relapse 50%. Key Words: bevacizumab, capecitabine, colorectal cancer, liver metastases, oxaliplati

    Self-organization of stack-up block copolymers into polymeric supramolecules

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    Polyethylene oxide –b– polypropylene oxide -b- polyethylene oxide (EO106PO70EO106) block copolymer self-organizes into polymeric supramolecules, characterized by NMR as phase transition from the isotropic stack-up block structure to the ordered cubic polymeric supramolecular structure. Its dependence on both temperature and copolymer concentration is clearly shown by the changes in line shape and chemical shift of the PO70blockÎČ,Îłresonances

    Glycemic Control and Clinical Outcomes in U.S. Patients With COVID-19: Data From the National COVID Cohort Collaborative (N3C) Database

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    OBJECTIVE The purpose of the study is to evaluate the relationship between HbA1c and severity of coronavirus disease 2019 (COVID-19) outcomes in patients with type 2 diabetes (T2D) with acute COVID-19 infection. RESEARCH DESIGN AND METHODS We conducted a retrospective study using observational data from the National COVID Cohort Collaborative (N3C), a longitudinal, multicenter U.S. cohort of patients with COVID-19 infection. Patients were ≄18 years old with T2D and confirmed COVID-19 infection by laboratory testing or diagnosis code. The primary outcome was 30-day mortality following the date of COVID-19 diagnosis. Secondary outcomes included need for invasive ventilation or extracorporeal membrane oxygenation (ECMO), hospitalization within 7 days before or 30 days after COVID-19 diagnosis, and length of stay (LOS) for patients who were hospitalized. RESULTS The study included 39,616 patients (50.9% female, 55.4% White, 26.4% Black or African American, and 16.1% Hispanic or Latino, with mean ± SD age 62.1 ± 13.9 years and mean ± SD HbA1c 7.6% ± 2.0). There was an increasing risk of hospitalization with incrementally higher HbA1c levels, but risk of death plateaued at HbA1c >8%, and risk of invasive ventilation or ECMO plateaued 9%. There was no significant difference in LOS across HbA1c levels. CONCLUSIONS In a large, multicenter cohort of patients in the U.S. with T2D and COVID-19 infection, risk of hospitalization increased with incrementally higher HbA1c levels. Risk of death and invasive ventilation also increased but plateaued at different levels of glycemic control

    X(3872) and Other Possible Heavy Molecular States

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    We perform a systematic study of the possible molecular states composed of a pair of heavy mesons such as DDˉD\bar D, D∗DˉD^\ast\bar D, D∗Dˉ∗D^\ast \bar D^\ast in the framework of the meson exchange model. The exchanged mesons include the pseudoscalar, scalar and vector mesons. Through our investigation, we find that (1) the structure X(3764) is not a molecular state; (2) There exists strong attraction in the range r<1r < 1 fm for the D∗Dˉ∗D^*\bar D^* system with J=0,1J=0, 1. If future experiments confirm Z+(4051)Z^+(4051) as a loosely bound molecular state, its quantum number is probably JP=0+J^{P}=0^+. Its partner state Ω∗∗0\Phi^{**0} may be searched for in the π0χc1\pi^0\chi_{c1} channel; (3) The vector meson exchange provides strong attraction in the D∗DˉD^\ast \bar D channel together with the pion exchange. A bound state solution exists with a reasonable cutoff parameter Λ∌1.4\Lambda\sim 1.4 GeV. X(3872) may be accommodated as a molecular state dynamically although drawing a very definite conclusion needs further investigation; (4) The B∗BˉB^\ast \bar B molecular state exists.Comment: 21 pages, 17 tables, 11 figures. Typos correcte

    Heavy quarkonium: progress, puzzles, and opportunities

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    A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the BB-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations. The plethora of newly-found quarkonium-like states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b}, and b\bar{c} bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K. Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D. Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A. Petrov, P. Robbe, A. Vair
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