870 research outputs found

    Characterization of the self-palmitoylation activity of the transport protein particle component Bet3

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    Bet3, a transport protein particle component involved in vesicular trafficking, contains a hydrophobic tunnel occupied by a fatty acid linked to cysteine 68. We reported that Bet3 has a unique self-palmitoylating activity. Here we show that mutation of arginine 67 reduced self-palmitoylation of Bet3, but the effect was compensated by increasing the pH. Thus, arginine helps to deprotonate cysteine such that it could function as a nucleophile in the acylation reaction which is supported by the structural analysis of non-acylated Bet3. Using fluorescence spectroscopy we show that long-chain acyl-CoAs bind with micromolar affinity to Bet3, whereas shorter-chain acyl-CoAs do not interact. Mutants with a deleted acylation site or a blocked tunnel bind to Pal-CoA, only the latter with slightly reduced affinity. Bet3 contains three binding sites for Pal-CoA, but their number was reduced to two in the mutant with an obstructed tunnel, indicating that Bet3 contains binding sites on its surface

    Thermodynamic laws, economic methods and the productive power of energy

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    Energy plays only a minor role in orthodox theories of economic growth, because standard economic equlibrium conditions say that the output elasticity of a production factor, which measures the factor's productive power, is equal to the factor's share in total factor cost. Having commanded only a tiny cost share of about 5 percent so far, energy is often neglected altogether. On the other hand, energy conversion in the machines of the capital stock has been the basis of industrial growth. How can the physically obvious economic importance of energy be reconciled with the conditions for economic equilibrium, which result from the maximization of profit or overall welfare? We show that these equilibrium conditions no longer yield the equality of cost shares and output elasticities, if the optimization calculus takes technological constraints on the combinations of capital, labor, and energy into account. New econometric analyses of economic growth in Germany, Japan, and the USA yield output elasticities that are for energy much larger and for labor much smaller than their cost shares. Social consequences are discussed

    DNA Methylation of the ABO Promoter Underlies Loss of ABO Allelic Expression in a Significant Proportion of Leukemic Patients

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    Background: Loss of A, B and H antigens from the red blood cells of patients with myeloid malignancies is a frequent occurrence. Previously, we have reported alterations in ABH antigens on the red blood cells of 55% of patients with myeloid malignancies. Methodology/Principal Findings: To determine the underlying molecular mechanisms of this loss, we assessed ABO allelic expression in 21 patients with ABH antigen loss previously identified by flow cytometric analysis as well as an additional 7 patients detected with ABH antigen changes by serology. When assessing ABO mRNA allelic expression, 6/12 (50%) patients with ABH antigen loss detected by flow cytometry and 5/7 (71%) of the patients with ABH antigen loss detected by serology had a corresponding ABO mRNA allelic loss of expression. We examined the ABO locus for copy number and DNA methylation alterations in 21 patients, 11 with loss of expression of one or both ABO alleles, and 10 patients with no detectable allelic loss of ABO mRNA expression. No loss of heterozygosity (LOH) at the ABO locus was observed in these patients. However in 8/11 (73%) patients with loss of ABO allelic expression, the ABO promoter was methylated compared with 2/10 (20%) of patients with no ABO allelic expression loss (P = 0.03). Conclusions/Significance: We have found that loss of ABH antigens in patients with hematological malignancies is associated with a corresponding loss of ABO allelic expression in a significant proportion of patients. Loss of ABO allelic expression was strongly associated with DNA methylation of the ABO promoter.Tina Bianco-Miotto, Damian J. Hussey, Tanya K. Day, Denise S. O'Keefe and Alexander Dobrovi

    Feasibility studies of the time-like proton electromagnetic form factor measurements with PANDA at FAIR

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    The possibility of measuring the proton electromagnetic form factors in the time-like region at FAIR with the \PANDA detector is discussed. Detailed simulations on signal efficiency for the annihilation of pˉ+p\bar p +p into a lepton pair as well as for the most important background channels have been performed. It is shown that precision measurements of the differential cross section of the reaction pˉ+p→e++e−\bar p +p \to e^++ e^- can be obtained in a wide angular and kinematical range. The individual determination of the moduli of the electric and magnetic proton form factors will be possible up to a value of momentum transfer squared of q2≃14q^2\simeq 14 (GeV/c)2^2. The total pˉ+p→e++e−\bar p +p\to e^++e^- cross section will be measured up to q2≃28q^2\simeq 28 (GeV/c)2^2. The results obtained from simulated events are compared to the existing data. Sensitivity to the two photons exchange mechanism is also investigated.Comment: 12 pages, 4 tables, 8 figures Revised, added details on simulations, 4 tables, 9 figure

    Observation of ηc→ωω\eta_c\to\omega\omega in J/ψ→γωωJ/\psi\to\gamma\omega\omega

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    Using a sample of (1310.6±7.0)×106(1310.6\pm7.0)\times10^6 J/ψJ/\psi events recorded with the BESIII detector at the symmetric electron positron collider BEPCII, we report the observation of the decay of the (11S0)(1^1 S_0) charmonium state ηc\eta_c into a pair of ω\omega mesons in the process J/ψ→γωωJ/\psi\to\gamma\omega\omega. The branching fraction is measured for the first time to be B(ηc→ωω)=(2.88±0.10±0.46±0.68)×10−3\mathcal{B}(\eta_c\to\omega\omega)= (2.88\pm0.10\pm0.46\pm0.68)\times10^{-3}, where the first uncertainty is statistical, the second systematic and the third is from the uncertainty of B(J/ψ→γηc)\mathcal{B}(J/\psi\to\gamma\eta_c). The mass and width of the ηc\eta_c are determined as M=(2985.9±0.7±2.1) M=(2985.9\pm0.7\pm2.1)\,MeV/c2c^2 and Γ=(33.8±1.6±4.1) \Gamma=(33.8\pm1.6\pm4.1)\,MeV.Comment: 13 pages, 6 figure

    Observation and study of the decay J/ψ→ϕηη′J/\psi\rightarrow\phi\eta\eta'

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    We report the observation and study of the decay J/ψ→ϕηη′J/\psi\rightarrow\phi\eta\eta' using 1.3×1091.3\times{10^9} J/ψJ/\psi events collected with the BESIII detector. Its branching fraction, including all possible intermediate states, is measured to be (2.32±0.06±0.16)×10−4(2.32\pm0.06\pm0.16)\times{10^{-4}}. We also report evidence for a structure, denoted as XX, in the ϕη′\phi\eta' mass spectrum in the 2.0−2.12.0-2.1 GeV/c2c^2 region. Using two decay modes of the η′\eta' meson (γπ+π−\gamma\pi^+\pi^- and ηπ+π−\eta\pi^+\pi^-), a simultaneous fit to the ϕη′\phi\eta' mass spectra is performed. Assuming the quantum numbers of the XX to be JP=1−J^P = 1^-, its significance is found to be 4.4σ\sigma, with a mass and width of (2002.1±27.5±21.4)(2002.1 \pm 27.5 \pm 21.4) MeV/c2c^2 and (129±17±9)(129 \pm 17 \pm 9) MeV, respectively, and a product branching fraction B(J/ψ→ηX)×B(X→ϕη′)=(9.8±1.2±1.7)×10−5\mathcal{B}(J/\psi\rightarrow\eta{}X)\times{}\mathcal{B}(X\rightarrow\phi\eta')=(9.8 \pm 1.2 \pm 1.7)\times10^{-5}. Alternatively, assuming JP=1+J^P = 1^+, the significance is 3.8σ\sigma, with a mass and width of (2062.8±13.1±7.2)(2062.8 \pm 13.1 \pm 7.2) MeV/c2c^2 and (177±36±35)(177 \pm 36 \pm 35) MeV, respectively, and a product branching fraction B(J/ψ→ηX)×B(X→ϕη′)=(9.6±1.4±2.0)×10−5\mathcal{B}(J/\psi\rightarrow\eta{}X)\times{}\mathcal{B}(X\rightarrow\phi\eta')=(9.6 \pm 1.4 \pm 2.0)\times10^{-5}. The angular distribution of J/ψ→ηXJ/\psi\rightarrow\eta{}X is studied and the two JPJ^P assumptions of the XX cannot be clearly distinguished due to the limited statistics. In all measurements the first uncertainties are statistical and the second systematic.Comment: 10 pages, 6 figures and 4 table

    Observation of Ds+→pnˉD^+_s\rightarrow p\bar{n} and confirmation of its large branching fraction

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    The baryonic decay Ds+→pnˉD^+_s\rightarrow p\bar{n} is observed, and the corresponding branching fraction is measured to be (1.21±0.10±0.05)×10−3(1.21\pm0.10\pm0.05)\times10^{-3}, where the first uncertainty is statistical and second systematic. The data sample used in this analysis was collected with the BESIII detector operating at the BEPCII e+e−e^+e^- double-ring collider with a center-of-mass energy of 4.178~GeV and an integrated luminosity of 3.19~fb−1^{-1}. The result confirms the previous measurement by the CLEO Collaboration and is of greatly improved precision, which may deepen our understanding of the dynamical enhancement of the W-annihilation topology in the charmed meson decays

    Evidence of a resonant structure in the e+e−→π+D0D∗−e^+e^-\to \pi^+D^0D^{*-} cross section between 4.05 and 4.60 GeV

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    The cross section of the process e+e−→π+D0D∗−e^+e^-\to \pi^+D^0D^{*-} for center-of-mass energies from 4.05 to 4.60~GeV is measured precisely using data samples collected with the BESIII detector operating at the BEPCII storage ring. Two enhancements are clearly visible in the cross section around 4.23 and 4.40~GeV. Using several models to describe the dressed cross section yields stable parameters for the first enhancement, which has a mass of 4228.6 \pm 4.1 \pm 6.3 \un{MeV}/c^2 and a width of 77.0 \pm 6.8 \pm 6.3 \un{MeV}, where the first uncertainties are statistical and the second ones are systematic. Our resonant mass is consistent with previous observations of the Y(4220)Y(4220) state and the theoretical prediction of a DDˉ1(2420)D\bar{D}_1(2420) molecule. This result is the first observation of Y(4220)Y(4220) associated with an open-charm final state. Fits with three resonance functions with additional Y(4260)Y(4260), Y(4320)Y(4320), Y(4360)Y(4360), ψ(4415)\psi(4415), or a new resonance, do not show significant contributions from either of these resonances. The second enhancement is not from a single known resonance. It could contain contributions from ψ(4415)\psi(4415) and other resonances, and a detailed amplitude analysis is required to better understand this enhancement

    Observation of the WW-Annihilation Decay Ds+→ωπ+D^{+}_{s} \rightarrow \omega \pi^{+} and Evidence for Ds+→ωK+D^{+}_{s} \rightarrow \omega K^{+}

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    We report on the observation of the WW-annihilation decay Ds+→ωπ+D^{+}_{s} \rightarrow \omega \pi^{+} and the evidence for Ds+→ωK+D_{s}^{+} \rightarrow \omega K^{+} with a data sample corresponding to an integrated luminosity of 3.19 fb−1^{-1} collected with the BESIII detector at the center-of-mass energy s=4.178\sqrt{s} = 4.178 GeV. We obtain the branching fractions B(Ds+→ωπ+)=(1.77±0.32stat.±0.11sys.)×10−3\mathcal{B}(D^{+}_{s} \rightarrow \omega \pi^{+}) = (1.77\pm0.32_{{\rm stat.}}\pm0.11_{{\rm sys.}}) \times 10^{-3} and B(Ds+→ωK+)=(0.87±0.24stat.±0.07sys.)×10−3\mathcal{B}(D^{+}_{s} \rightarrow \omega K^{+}) = (0.87\pm0.24_{{\rm stat.}}\pm0.07_{{\rm sys.}}) \times 10^{-3}, respectively
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