556 research outputs found

    Palladium nanoparticles supported on Smopex®metal scavengers ascatalyst for carbonylative Sonogashira reactions: Synthesis of α,β-alkynyl ketones

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    Palladium nanoparticles supported on two Smopex®commercial metal scavengers (1% w/w) have beentested in the carbonylative Sonogashira reactions of aryl iodides with phenylacetylene. Their catalyticactivity has been compared with those of more common catalysts (Pd/C, Pd/-Al2O3). Pd/Smopex®-234resulted especially effective in the synthesis of alkynyl ketones even working with a low amount ofpalladium (0.2–0.5 mol%). Preliminary heterogeneity tests (i.e. hot filtration test, Pd leaching and recycleof the catalyst) have been performed in order to evaluate the catalytic behaviour of this system. Theobtained results seem to indicate that Pd/Smopex®-234 could act as a truly heterogeneous catalyst

    A new iron free treatment with oral fi sh cartilage polysaccharide for iron defi ciency chronic anemia in infl ammatory bowel diseases: A pilot study

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    Abstract AIM: To investigate the effect of a new oral preparation, highly concentrated in fish cartilage, in a group of infl ammatory bowel diseases (IBD) patients with chronic iron defi cient anemia. METHODS: In an open label pilot study, we supplemented a group of 25 patients (11 with Crohn's disease and 14 with ulcerative colitis) in stable clinical conditions and chronic anemia with a food supplement which does not contain iron but contains a standardized fraction of fish cartilage glycosaminoglycans and a mixture of antioxidants (Captafer Medestea, Turin, Italy). Patients received 500 mg, twice a day during meals, for at least 4 mo. Patients were suggested to maintain their alimentary habit. At time 0 and after 2 and 4 mo, emocrome, sideremia and ferritin were examined. Paired data were analyzed with Student's t test. RESULTS: Three patients relapsed during the study (2 in the 3 rd mo, 1 in the 4 th mo), two patients were lost to follow up and two patients dropped out (1 for orticaria, 1 for gastric burning). Of the remaining 18 patients, levels of serum iron started to rapidly increase within the 2 nd mo of treatment, P < 0.05), whereas serum ferritin and hemoglobin needed a longer period to signifi cantly improve their serum levels (mo 4) P < 0.05). The product was safe, easy to administer and well tolerated by patients. CONCLUSION: These data suggest a potential new treatment for IBD patients with iron defi ciency chronic anemia and warrant further larger controlled studies

    Multidifferential study of identified charged hadron distributions in ZZ-tagged jets in proton-proton collisions at s=\sqrt{s}=13 TeV

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    Jet fragmentation functions are measured for the first time in proton-proton collisions for charged pions, kaons, and protons within jets recoiling against a ZZ boson. The charged-hadron distributions are studied longitudinally and transversely to the jet direction for jets with transverse momentum 20 <pT<100< p_{\textrm{T}} < 100 GeV and in the pseudorapidity range 2.5<η<42.5 < \eta < 4. The data sample was collected with the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 1.64 fb1^{-1}. Triple differential distributions as a function of the hadron longitudinal momentum fraction, hadron transverse momentum, and jet transverse momentum are also measured for the first time. This helps constrain transverse-momentum-dependent fragmentation functions. Differences in the shapes and magnitudes of the measured distributions for the different hadron species provide insights into the hadronization process for jets predominantly initiated by light quarks.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-013.html (LHCb public pages

    Study of the BΛc+ΛˉcKB^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} decay

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    The decay BΛc+ΛˉcKB^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} is studied in proton-proton collisions at a center-of-mass energy of s=13\sqrt{s}=13 TeV using data corresponding to an integrated luminosity of 5 fb1\mathrm{fb}^{-1} collected by the LHCb experiment. In the Λc+K\Lambda_{c}^+ K^{-} system, the Ξc(2930)0\Xi_{c}(2930)^{0} state observed at the BaBar and Belle experiments is resolved into two narrower states, Ξc(2923)0\Xi_{c}(2923)^{0} and Ξc(2939)0\Xi_{c}(2939)^{0}, whose masses and widths are measured to be m(Ξc(2923)0)=2924.5±0.4±1.1MeV,m(Ξc(2939)0)=2938.5±0.9±2.3MeV,Γ(Ξc(2923)0)=0004.8±0.9±1.5MeV,Γ(Ξc(2939)0)=0011.0±1.9±7.5MeV, m(\Xi_{c}(2923)^{0}) = 2924.5 \pm 0.4 \pm 1.1 \,\mathrm{MeV}, \\ m(\Xi_{c}(2939)^{0}) = 2938.5 \pm 0.9 \pm 2.3 \,\mathrm{MeV}, \\ \Gamma(\Xi_{c}(2923)^{0}) = \phantom{000}4.8 \pm 0.9 \pm 1.5 \,\mathrm{MeV},\\ \Gamma(\Xi_{c}(2939)^{0}) = \phantom{00}11.0 \pm 1.9 \pm 7.5 \,\mathrm{MeV}, where the first uncertainties are statistical and the second systematic. The results are consistent with a previous LHCb measurement using a prompt Λc+K\Lambda_{c}^{+} K^{-} sample. Evidence of a new Ξc(2880)0\Xi_{c}(2880)^{0} state is found with a local significance of 3.8σ3.8\,\sigma, whose mass and width are measured to be 2881.8±3.1±8.5MeV2881.8 \pm 3.1 \pm 8.5\,\mathrm{MeV} and 12.4±5.3±5.8MeV12.4 \pm 5.3 \pm 5.8 \,\mathrm{MeV}, respectively. In addition, evidence of a new decay mode Ξc(2790)0Λc+K\Xi_{c}(2790)^{0} \to \Lambda_{c}^{+} K^{-} is found with a significance of 3.7σ3.7\,\sigma. The relative branching fraction of BΛc+ΛˉcKB^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} with respect to the BD+DKB^{-} \to D^{+} D^{-} K^{-} decay is measured to be 2.36±0.11±0.22±0.252.36 \pm 0.11 \pm 0.22 \pm 0.25, where the first uncertainty is statistical, the second systematic and the third originates from the branching fractions of charm hadron decays.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-028.html (LHCb public pages

    Measurement of the ratios of branching fractions R(D)\mathcal{R}(D^{*}) and R(D0)\mathcal{R}(D^{0})

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    The ratios of branching fractions R(D)B(BˉDτνˉτ)/B(BˉDμνˉμ)\mathcal{R}(D^{*})\equiv\mathcal{B}(\bar{B}\to D^{*}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(\bar{B}\to D^{*}\mu^{-}\bar{\nu}_{\mu}) and R(D0)B(BD0τνˉτ)/B(BD0μνˉμ)\mathcal{R}(D^{0})\equiv\mathcal{B}(B^{-}\to D^{0}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(B^{-}\to D^{0}\mu^{-}\bar{\nu}_{\mu}) are measured, assuming isospin symmetry, using a sample of proton-proton collision data corresponding to 3.0 fb1{ }^{-1} of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode τμντνˉμ\tau^{-}\to\mu^{-}\nu_{\tau}\bar{\nu}_{\mu}. The measured values are R(D)=0.281±0.018±0.024\mathcal{R}(D^{*})=0.281\pm0.018\pm0.024 and R(D0)=0.441±0.060±0.066\mathcal{R}(D^{0})=0.441\pm0.060\pm0.066, where the first uncertainty is statistical and the second is systematic. The correlation between these measurements is ρ=0.43\rho=-0.43. Results are consistent with the current average of these quantities and are at a combined 1.9 standard deviations from the predictions based on lepton flavor universality in the Standard Model.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-039.html (LHCb public pages

    Survival Benefit of Liver Transplantation Versus Resection for Hepatocellular Carcinoma: Impact of MELD Score

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    We sought to measure the impact of model for end stage liver disease (MELD) score, tumor staging, and microvascular invasion (MVI) on the relative survival benefit of liver transplantation (LT) versus liver resection (LR) for hepatocellular carcinoma (HCC). The study population comprised 1,106 HCC patients with cirrhosis undergoing LR from one Eastern (n = 424) and two Western (n = 682) surgical units. Exclusion criteria were very large (> 10 cm) tumors, macrovascular invasion, and metastases. We identified three tumor stages: stage I (within Milan, n = 806), stage II (beyond Milan within Up-to-7, n = 123), and stage III (beyond Milan and Up-to-7, n = 177). Patient survival after LR was compared to that predicted after LT by the Metroticket calculator in relationship with staging, MVI, and MELD score using Monte Carlo simulation. Two hundred eighty-three patients (26 %) with a MELD score of a parts per thousand yen10 had an acceptable 5-year survival after LR of 47 %, while that of patients with a low MELD score was 67 % (p < 0.0001). Mean 5-year LT benefit was -4.50 months (95 % confidence interval [CI] -4.73 to -4.27) for patients with a MELD score of < 10, and 0.81 months (95 % CI 0.58 to 1.04) for those with a MELD score of a parts per thousand yen10. MELD score and MVI were the strongest predictors of transplant survival benefit. LT reached a survival benefit, versus LR only in HCC patients with a MELD score of a parts per thousand yen10 and without MVI (3.08 months, 95 % CI 2.78 to 3.39), whatever the tumor stage. LT proved to be harmful in patients with resectable HCC with a low MELD score (< 10) or with aggressive tumors (with MVI). As a result of a shortage of donors, only selected resectable tumors with a MELD score of a parts per thousand yen10 should be considered for transplantatio

    First Measurement of Charm Production in its Fixed-Target Configuration at the LHC

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    International audienceThe first measurement of heavy-flavor production by the LHCb experiment in its fixed-target mode is presented. The production of J/ψ and D0 mesons is studied with beams of protons of different energies colliding with gaseous targets of helium and argon with nucleon-nucleon center-of-mass energies of sNN=86.6 and 110.4 GeV, respectively. The J/ψ and D0 production cross sections in pHe collisions in the rapidity range [2, 4.6] are found to be σJ/ψ=652±33(stat)±42(syst)   nb/nucleon and σD0=80.8±2.4(stat)±6.3(syst)  μb/nucleon, where the first uncertainty is statistical and the second is systematic. No evidence for a substantial intrinsic charm content of the nucleon is observed in the large Bjorken-x region

    Model-Independent Observation of Exotic Contributions to B0J/ψK+πB^0\to J/\psi K^+\pi^- Decays

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    International audienceAn angular analysis of B0→J/ψK+π- decays is performed, using proton-proton collision data corresponding to an integrated luminosity of 3  fb-1 collected with the LHCb detector. The m(K+π-) spectrum is divided into fine bins. In each m(K+π-) bin, the hypothesis that the three-dimensional angular distribution can be described by structures induced only by K* resonances is examined, making minimal assumptions about the K+π- system. The data reject the K*-only hypothesis with a large significance, implying the observation of exotic contributions in a model-independent fashion. Inspection of the m(J/ψπ-) vs m(K+π-) plane suggests structures near m(J/ψπ-)=4200 and 4600 MeV
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