116 research outputs found

    The reaction 2H(p,pp)n in three kinematical configurations at E_p = 16 MeV

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    We measured the cross sections of the 2^2H(p,pp)n breakup reaction at Ep_p=16 MeV in three kinematical configurations: the np final-state interaction (FSI), the co-planar star (CST), and an intermediate-star (IST) geometry. The cross sections are compared with theoretical predictions based on the CD Bonn potential alone and combined with the updated 2π\pi-exchange Tucson-Melbourne three-nucleon force (TM99'), calculated without inclusion of the Coulomb interaction. The resulting excellent agreement between data and pure CD Bonn predictions in the FSI testifies to the smallness of three-nucleon force (3NF) effects as well as the insignificance of the Coulomb force for this particular configuration and energy. The CST also agrees well whereas the IST results show small deviations between measurements and theory seen before in the pd breakup space-star geometries which point to possible Coulomb effects. An additional comparison with EFT predictions (without 3NF) up to order N3^3LO shows excellent agreement in the FSI case and a rather similar agreement as for CD Bonn in the CST and IST situations.Comment: 20 pages, 11 figure

    Chromane derivatives from underground parts of Iris tenuifolia and their in vitro antimicrobial, cytotoxicity and antiproliferative evaluation

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    Phytochemical investigation of the ethanol extract of underground parts of Iris tenuifolia Pall. afforded five new compounds; an unusual macrolide termed moniristenulide (1), 5-methoxy-6,7-methylenedioxy-4-O-2′-cycloflavan (2), 5,7,2′,3′-tetrahydroxyflavanone (3), 5-hydroxy-6,7-dimethoxyisoflavone-2′-O-β-d-glucopyranoside (9), 5,2′,3′-dihydroxy-6,7-dimethoxyisoflavone (10), along with seven known compounds (4–8, 11–12). The structures of all purified compounds were established by analysis of 1D and 2D NMR spectroscopy and HR-ESI-MS. The antimicrobial activity of the compounds 1–3, 5, 9, and 10 was investigated using the agar diffusion method against fungi, Gram-positive and Gram-negative bacteria. In consequence, new compound 3 was found to possess the highest antibacterial activity against Enterococcus faecalis VRE and Mycobacterium vaccae. Cell proliferation and cytotoxicity tests were also applied on all isolated compounds and plant crude extract in vitro with the result of potent inhibitory effect against leukemia cells. In particular, the newly discovered isoflavone 10 was active against both of the leukemia cells K-562 and THP-1 while 4–6 of the flavanone type compounds were active against only THP-1

    Proton--induced deuteron breakup at GeV energies with forward emission of a fast proton pair

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    A study of the deuteron breakup reaction pd(pp)npd \to (pp)n with forward emission of a fast proton pair with small excitation energy Epp<E_{pp}< 3 MeV has been performed at the ANKE spectrometer at COSY--J\"ulich. An exclusive measurement was carried out at six proton--beam energies Tp=T_p=~0.6,~0.7,~0.8,~0.95,~1.35, and 1.9 GeV by reconstructing the momenta of the two protons. The differential cross section of the breakup reaction, averaged up to 88^{\circ} over the cm polar angle of the total momentum of the pppp pairs, has been obtained. Since the kinematics of this process is quite similar to that of backward elastic pddppd \to dp scattering, the results are compared to calculations based on a theoretical model previously applied to the pddppd \to dp process.Comment: 17 pages including 6 figures and 1 table v2: minor changes; v3: minor change of author list; v4: changes in accordance with referee remark

    Forward K+ production in subthreshold pA collisions at 1.0 GeV

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    K+ meson production in pA (A = C, Cu, Au) collisions has been studied using the ANKE spectrometer at an internal target position of the COSY-Juelich accelerator. The complete momentum spectrum of kaons emitted at forward angles, theta < 12 degrees, has been measured for a beam energy of T(p)=1.0 GeV, far below the free NN threshold of 1.58 GeV. The spectrum does not follow a thermal distribution at low kaon momenta and the larger momenta reflect a high degree of collectivity in the target nucleus.Comment: 4 pages, 3 figure

    Signatures of three-nucleon interactions in few-nucleon systems

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    Recent experimental results in three-body systems have unambiguously shown that calculations based only on nucleon-nucleon forces fail to accurately describe many experimental observables and one needs to include effects which are beyond the realm of the two-body potentials. This conclusion owes its significance to the fact that experiments and calculations can both be performed with a high accuracy. In this review, both theoretical and experimental achievements of the past decade will be underlined. Selected results will be presented. The discussion on the effects of the three-nucleon forces is, however, limited to the hadronic sector. It will be shown that despite the major successes in describing these seemingly simple systems, there are still clear discrepancies between data and the state-of-the-art calculations.Comment: accepted for publication in Rep. Prog. Phy

    Three-Nucleon Force Effects in Nucleon Induced Deuteron Breakup: Comparison to Data (II)

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    Selected Nd breakup data over a wide energy range are compared to solutions of Faddeev equations based on modern high precision NN interactions alone and adding current three-nucleon force models. Unfortunately currently available data probe phase space regions for the final three nucleon momenta which are rather insensitive to 3NF effects as predicted by current models. Overall there is good to fair agreement between present day theory and experiment but also some cases exist with striking discrepancies. Regions in the phase space are suggested where large 3NF effects can be expected.Comment: 33 pages, 24 ps figures, 9 gif figure

    Assessing ecotoxicity of an innovative bio-based mulch film: a multi-environmental and multi-bioassay approach

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    Among the highly diverse range of biobased polymers, polylactic acid (PLA) received vast attention in recent years due to its versatility for different applications and being the first commercially used polymer produced from renewable sources. Production and application of bio-based, biodegradable plastics will have one of the most crucial roles in tackling worldwide plastic pollution. Methods: This study is based on integrative ecotoxicological assessment of an innovative PLA-based agricultural mulch film (BPE-AMF-PLA), developed under the H2020 EU project “BIO-PLASTICS EUROPE”, towards organisms from different environmental compartments (soil, fresh water and marine) and from different trophic levels. Such comprehensive evaluation has an overarching goal to promote environmentally safe and sustainable use of these PLA-based plastics for agricultural and other potential applications. Results: Low-to-no phytotoxicity was obtained in both single-species standardized bioassays, and in a multi-species microcosms experiment. Earthworm reproduction was negatively affected at the lowest test concentration of 0.1% w/w of PLA-based plastic particles. For freshwater Daphnia, reproduction was found a sensitive endpoint, upon exposure to the leachates of the PLA-based plastic. However, the reported toxicity seemed to be caused by the presence of 2-methylnaphthalene, which can be avoided in the production process. As for the marine organisms, algae growth was inhibited with a LOEC = 25 g L−1, whereas test with brine shrimp only revealed stimulation of lipase upon digestion of micro-sized PLA-based plastics. Marine lugworm ingested pristine and UV pre-treated micro-sized plastics, yet without impact either on biological activity, or on the health of the test individuals. Discussion: The approach used in the present work will contribute to product development, environmental safety and sustainable applications of the PLA-based mulch film BPE-AMF-PLA, in the scope of project BIO-PLASTICS EUROPE. Furthermore, the tools and results obtained in this work are a relevant contribution in the framework development for additional support in the certification of the bio-based polymers, being aligned with European zero waste and non-toxicity strategies, certification, and regulations
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