29,798 research outputs found
Preparation of 'side-chain-to-side-chain' cyclic peptides by Allyl and Alloc strategy: Potential for library synthesis
No full textAutomated and manual deprotection methods for allyl/allyloxycarbonyl (Allyl/Alloc) were evaluated for the prepn. of side-chain-to-side-chain cyclic peptides. Using a std. Allyl/Alloc deprotection method, a small library of cyclic peptides with lactam bridges (with seven amino acids) was prepd. on an automatic peptide synthesizer. We demonstrate that the Guibe method for removing Allyl/Alloc protecting groups under specific neutral conditions [Pd(PPh3)4/PhSiH3/DCM] can be a useful, efficient and reliable method for prepg. long cyclic peptides on a resin. We have also manually synthesized a cyclic glucagon analog contg. 24 amino acid residues. These results demonstrated that properly controlled palladium-mediated deprotection of Allyl/Alloc protecting groups can be used to prep. cyclic peptides on the resin using an automated peptide synthesizer and cyclic peptides with a long chain
Evidence for the decay B0→J/ψω and measurement of the relative branching fractions of meson decays to J/ψη and J/ψη′
Get PDFFirst evidence of the B 0 → J / ψ ω decay is found and the B s 0 → J / ψ η and B s 0 → J / ψ η ′ decays are studied using a dataset corresponding to an integrated luminosity of 1.0 fb -1 collected by the LHCb experiment in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV. The branching fractions of these decays are measured relative to that of the B 0 → J / ψ ρ 0 decay:frac(B (B 0 → J / ψ ω), B (B 0 → J / ψ ρ 0)) = 0.89 ± 0.19 (stat) - 0.13 + 0.07 (syst),frac(B (B s 0 → J / ψ η), B (B 0 → J / ψ ρ 0)) = 14.0 ± 1.2 (stat) - 1.5 + 1.1 (syst) - 1.0 + 1.1 (frac(f d, f s)),frac(B (B s 0 → J / ψ η ′), B (B 0 → J / ψ ρ 0)) = 12.7 ± 1.1 (stat) - 1.3 + 0.5 (syst) - 0.9 + 1.0 (frac(f d, f s)), where the last uncertainty is due to the knowledge of f d / f s, the ratio of b-quark hadronization factors that accounts for the different production rate of B 0 and B s 0 mesons. The ratio of the branching fractions of B s 0 → J / ψ η ′ and B s 0 → J / ψ η decays is measured to befrac(B (B s 0 → J / ψ η ′), B (B s 0 → J / ψ η)) = 0.90 ± 0.09 (stat) - 0.02 + 0.06 (syst)
Letter from Carl Hayden to J. V. Lloyd
No full textLetter from Carl Hayden to J. V. Lloyd, Assistant Superintendent of Grand Canyon National Park, thanking him for his support in maintaining Civilian Conservation Corp companies at full strength. Handwritten note in red pencil, "Jack - For my attention in January. Hayden"
Substitution of Arginine with Proline and Proline Derivatives in MSH Leads to Selectivity for Human Melanocortin 4 Receptor (hMC4R)
No full textMeasurement of the ratio of prompt χ c to J / ψ production in pp collisions at √s = 7 TeV
Get PDFThe 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
Structure-activity studies of new melanocortin peptides containing an aromatic amino acid at the N-terminal position
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