535,591 research outputs found

    Molecular structure of highly excited resonant states in Mg-24 and the corresponding Be-8+O-16 and C-12+C-12 decays

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    Exotic Be-8 and C-12 decays from high-lying resonances in Mg-24 are analyzed in terms of a cluster model. The calculated quantities agree well with the corresponding experimental data. It is found that the calculated decay widths are very sensitive to the angular momentum carried by the outgoing cluster. It is shown that this property makes cluster decay a powerful tool to determine the spin as well as the molecular structures of the resonances.Physics, NuclearSCI(E)7ARTICLE5null8

    Mitomycin C in highly myopic eyes - Author reply

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    Ophthalmology. 2005 Feb;112(2):208-18; discussion 219. Mitomycin C modulation of corneal wound healing after photorefractive keratectomy in highly myopic eyes. Gambato C, Ghirlando A, Moretto E, Busato F, Midena E. SourceRefractive Surgery Service and Antimetabolite Therapy Research Unit, Department of Ophthalmology, University of Padova, Padova, Italy. Abstract PURPOSE: To evaluate the role of topical mitomycin C in corneal wound healing (CWH) after photorefractive keratectomy (PRK) in highly myopic eyes. DESIGN: Prospective, double-masked, randomized clinical trial. PARTICIPANTS: Seventy-two eyes of 36 patients affected by high (>7 diopters) myopia. METHODS: In each patient, one eye was randomly assigned to PRK with intraoperative topical 0.02% mitomycin C application, and the fellow eye was treated with a placebo. Postoperatively, mitomycin C-treated eyes received artificial tears (3 times daily, tapered in 3 months), whereas the fellow eye was treated with fluorometholone sodium 2% and artificial tears (3 times daily, tapered in 3 months). MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), contrast sensitivity, manifest refraction, and biomicroscopy. Contrast sensitivity was determined using the Pelli-Robson chart. Corneal confocal microscopy documented CWH. RESULTS: Mean follow-up was 18 months (range, 12-36). No side effects or toxic effects were documented. At 12-month follow-up examination, UCVAs (logarithm of the minimum angle of resolution) were 0.4+/-0.48 and 0.5+/-0.53 (P = .03) in mitomycin C-treated eyes and corticosteroid-treated eyes, respectively. At 1 year, corneal haze developed in 20% of corticosteroid-treated eyes, versus 0% of mitomycin C-treated eyes. At 12, 24, and 36 months, corneal confocal microscopy showed activated keratocytes and extracellular matrix significantly more evident in untreated eyes (Ps = 0.004, 0.024, and 0.046, respectively). CONCLUSION: Topical intraoperative application of 0.02% mitomycin C can reduce haze formation in highly myopic eyes undergoing PRK. Comment in Ophthalmology. 2006 Feb;113(2):357; author reply 357-8

    Manganese(I)-Catalyzed Substitutive C-H Allylation

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    The first manganese(I)-catalyzed C-H allylations with ample scope were achieved by carboxylate assistance. The highly selective C-H/C-O functionalizations proved viable with densely substituted allyl carbonates, and the organometallic C-H allylation strategy set the stage for expedient latestage diversification with excellent levels of positional selectivity

    Nickel‐Catalyzed Electrooxidative C−H Amination: Support for Nickel(IV)

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    Abstract Nickel‐catalyzed electrochemical C−H aminations were accomplished by chemo‐ and position‐selective C−H activation with ample scope. Detailed mechanistic studies highlighted a facile C−H cleavage with unique chemo‐selectivity, while cyclovoltammetric analysis provided support for a nickel(II/III/IV) manifold.Distinguished International Students Scholarship https://doi.org/10.13039/501100010893Deutsche Forschungsgemeinschaft https://doi.org/10.13039/501100001659Alexander von Humboldt-Stiftung https://doi.org/10.13039/10000515

    Measurement of the ratio of prompt χ c to J / ψ production in pp collisions at √s = 7 TeV

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    The prompt production of charmonium χ c and J / ψ states is studied in proton-proton collisions at a centre-of-mass energy of √s = 7 TeV at the Large Hadron Collider. The χ c and J / ψ mesons are identified through their decays χ c → J / ψ γ and J / ψ → μ + μ - using 36 pb - 1 of data collected by the LHCb detector in 2010. The ratio of the prompt production cross-sections for χ c and J / ψ, σ (χ c → J / ψ γ) / σ (J / ψ), is determined as a function of the J / ψ transverse momentum in the range 2 < p T J / ψ < 15 GeV / c. The results are in excellent agreement with next-to-leading order non-relativistic expectations and show a significant discrepancy compared with the colour singlet model prediction at leading order, especially in the low p T J / ψ region

    B -&gt; eta K-c(eta &apos; K-c) decays in QCD factorization

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    We study the exclusive decays of the B meson into pseudoscalar charmonium states eta(c) and eta(c)&apos; within the QCD factorization approach and find that the non-factorizable corrections to naive factorization are infrared safe at leading-twist order. The spectator interactions arising from the kaon twist-3 effects are formally power suppressed but chirally and logarithmically enhanced. An important improvement by including the O(alpha(s)) corrections is the cancellation of the renormalization scale mu dependence of the decay amplitude. However, the calculated decay rates are too small to accommodate the experimental data. On the other hand, we compare the theoretical calculations for B meson decays to J/psi, psi&apos;, eta(c) and eta&apos;(c), and find that the predicted relative decay rates of these four states are approximately compatible with the experimental data.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000223097800007&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Physics, Particles &amp; FieldsSCI(E)17ARTICLE3365-3703

    GeoBalance VBA program

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    GeoBalance: an Excel VBA program for mass balance calculation in geosciences (by Li X., Zhang C., Almeev R., Holtz F.

    Microscopic mechanism of charged-particle radioactivity and generalization of the Geiger-Nuttall law

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    A linear relation for charged-particle emissions is presented starting from the microscopic mechanism of the radioactive decay. It relates the logarithms of the decay half-lives with two variables, called. chi&apos; and. rho&apos;, which depend upon the Q values of the outgoing clusters as well as the masses and charges of the nuclei involved in the decay. This relation explains well all known cluster decays. It is found to be a generalization of the Geiger-Nuttall law in a radioactivity, and therefore we call it the universal decay law. Predictions of the most likely emissions of various clusters are presented by applying the law over the whole nuclear chart. It is seen that the decays of heavier clusters with nonequal proton and neutron numbers are mostly located in the trans-lead region. The emissions of clusters with equal protons and neutrons, like (12)C and (16)O, are possible in some neutron-deficient nuclei with Z &gt;= 54.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000271352900039&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Physics, NuclearSCI(E)51ARTICLE4null8

    Evolution of High‐Valent Nickela‐Electrocatalyzed C−H Activation: From Cross(‐Electrophile)‐Couplings to Electrooxidative C−H Transformations

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    Abstract C−H activation has emerged as one of the most efficient tools for the formation of carbon–carbon and carbon–heteroatom bonds, avoiding the use of prefunctionalized materials. In spite of tremendous progress in the field, stoichiometric quantities of toxic and/or costly chemical redox reagents, such as silver(I) or copper(II) salts, are largely required for oxidative C−H activations. Recently, electrosynthesis has experienced a remarkable renaissance that enables the use of storable, safe and waste‐free electric current as a redox equivalent. While major recent momentum was gained in electrocatalyzed C−H activations by 4d and 5d metals, user‐friendly and inexpensive nickela‐electrocatalysis has until recently proven elusive for oxidative C−H activations. Herein, the early developments of nickela‐electrocatalyzed reductive cross‐electrophile couplings as well as net‐redox‐neutral cross‐couplings are first introduced. The focus of this Minireview is, however, the recent emergence of nickel‐catalyzed electrooxidative C−H activations until April 2020.Go electro! Nickela‐electrocatalyzed C−H activations have emerged as a sustainable platform in molecular sciences that avoid substrate prefunctionalizations and chemical oxidants by electricity. The robust nickela‐electrooxidations enabled C−C, C−O, and C−N formations with ample scope under exceedingly mild conditions. imageAlexander von Humboldt-Stiftung http://dx.doi.org/10.13039/100005156China Scholarship Council http://dx.doi.org/10.13039/501100004543DFG http://dx.doi.org/10.13039/50110000165

    History sketch 157th Engineer (C) Bn.

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    This is a historical description of the 157th Engineer (C) Battalion written from memory by author. Notes are not attached as described on last page of document
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