346 research outputs found

    Impact of Nucleon Mass Shift on the Freeze Out Process

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    The freeze out of a massive nucleon gas through a finite layer with time-like normal is studied. The impact of in-medium nucleon mass shift on the freeze out process is investigated. A considerable modification of the thermodynamical variables temperature, flow-velocity, energy density and particle density has been found. Due to the nucleon mass shift the freeze out particle distribution functions are changed noticeably in comparison with evaluations, which use vacuum nucleon mass.Comment: submitted to Physical Review

    Transient trimethylaminuria related to menstruation

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    BACKGROUND: Trimethylaminuria, or fish odor syndrome, includes a transient or mild malodor caused by an excessive amount of malodorous trimethylamine as a result of body secretions. Herein, we describe data to support the proposal that menses can be an additional factor causing transient trimethylaminuria in self-reported subjects suffering from malodor and even in healthy women harboring functionally active flavin-containing monooxygenase 3 (FMO3). METHODS: FMO3 metabolic capacity (conversion of trimethylamine to trimethylamine N-oxide) was defined as the urinary ratio of trimethylamine N-oxide to total trimethylamine. RESULTS: Self-reported Case (A) that was homozygous for inactive Arg500stop FMO3, showed decreased metabolic capacity of FMO3 (i.e., ~10% the unaffected metabolic capacity) during 120 days of observation. For Case (B) that was homozygous for common [Glu158Lys; Glu308Gly] FMO3 polymorphisms, metabolic capacity of FMO3 was almost ~90%, except for a few days surrounding menstruation showing < 40% metabolic capacity. In comparison, three healthy control subjects that harbored heterozygous polymorphisms for [Glu158Lys; Glu308Gly] FMO3 or homozygous for wild FMO3 showed normal (> 90%) metabolic capacity, however, on days around menstruation the FMO3 metabolic capacity was decreased to ~60–70%. CONCLUSION: Together, these results indicate that abnormal FMO3 capacity is caused by menstruation particularly in the presence, in homozygous form, of mild genetic variants such as [Glu158Lys; Glu308Gly] that cause a reduced FMO3 function

    ost in promiscuity? An evolutionary and biochemical evaluation of HSD10 function in cardiolipin metabolism

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    Multifunctional proteins are challenging as it can be difficult to confirm pathomechanisms associated with disease-causing genetic variants. The human 17β-hydroxysteroid dehydrogenase 10 (HSD10) is a moonlighting enzyme with at least two structurally and catalytically unrelated functions. HSD10 disease was originally described as a disorder of isoleucine metabolism, but the clinical manifestations were subsequently shown to be linked to impaired mtDNA transcript processing due to deficient function of HSD10 in the mtRNase P complex. A surprisingly large number of other, mostly enzymatic and potentially clinically relevant functions have been attributed to HSD10. Recently, HSD10 was reported to exhibit phospholipase C-like activity towards cardiolipins (CL), important mitochondrial phospholipids. To assess the physiological role of the proposed CL-cleaving function, we studied CL architectures in living cells and patient fibroblasts in different genetic backgrounds and lipid environments using our well-established LC–MS/MS cardiolipidomic pipeline. These experiments revealed no measurable effect on CLs, indicating that HSD10 does not have a physiologically relevant function towards CL metabolism. Evolutionary constraints could explain the broad range of reported substrates for HSD10 in vitro. The combination of an essential structural with a non-essential enzymatic function in the same protein could direct the evolutionary trajectory towards improvement of the former, thereby increasing the flexibility of the binding pocket, which is consistent with the results presented here

    Rho - Omega Splitting and Mixing in Nuclear Matter

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    We investigate the splitting and mixing of ρ\rho and ω\omega mesons in nuclear matter. The calculations were performed on the basis of QCD sum rules and include all operators up to mass dimension-6 twist-4 and up to first order in the coupling constants. Special attention is devoted to the impact of the scalar 4-quark condensates on both effects. In nuclear matter the Landau damping governs the ρω\rho - \omega mass splitting while the scalar 4-quark condensates govern the strenght of individual mass shifts. A strong in-medium mass splitting causes the disappearance of the ρω\rho - \omega mixing.Comment: 28 pages, 8 figures, Phys. Rev. C 70 (2004) 03520

    Study of in-medium ω\omega meson properties in Ap, pA and AA collisions

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    We propose to investigate the in-medium properties of vector ω\omega mesons at the normal nuclear density in Ap(pA) collisions and at higher density in AA collisions at the ITEP accelerator facility TWAC. Using of the inverse Ap kinematics will permit us to study the ω\omega meson production in a wide momentum interval included the not yet explored range of small meson momenta relative to the projectile nuclei where the mass modification effect in nuclear matter is expected to be the strongest. Momentum dependence of the in-medium ω\omega meson width will be studied in the traditional pA kinematics. We intend to use the electromagnetic calorimeter for reconstruction of the ω\omega meson invariant mass by detecting photons from the ωπ0γ3γ\omega \to \pi^{0}\gamma \to 3\gamma decay. The model calculations and simulations with RQMD generator show feasibility of the proposed experiment. Available now intensity of the ion beams provides a possibility to collect large statistics and make decisive conclusion about the ω\omega meson properties at density of normal nuclei. At the second stage of the investigation the ω\omega meson properties will be studied in AA collisions at higher density. Interpretation of these measurements will be based on the results obtained in Ap(pA) interactions. Further investigation of the in-medium properties of light unflavored and charmed mesons can be performed at ITEP and at GSI(FAIR) where higher ion energies will be accessible in near future.Comment: 26 pages, 10 figures, 2 table

    Absorption of phi mesons in near-threshold proton-nucleus reactions

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    In the framework of the nuclear spectral function approach for incoherent primary proton--nucleon and secondary pion--nucleon production processes we study the inclusive ϕ\phi meson production in the interaction of 2.83 GeV protons with nuclei. In particular, the A-dependences of the absolute and relative ϕ\phi meson yields are investigated within the different scenarios for its in-medium width as well as for the cross section ratio σpnpnϕ/σppppϕ\sigma_{pn \to pn{\phi}}/{\sigma_{pp \to pp{\phi}}}. Our model calculations take into account the acceptance window of the ANKE facility used in a recent experiment performed at COSY. They show that the pion--nucleon production channel contributes distinctly to the ϕ\phi creation in heavy nuclei in the chosen kinematics and, hence, has to be taken into consideration on close examination of the dependences of the phi meson yields on the target mass number with the aim to get information on its width in the medium. They also demonstrate that the experimentally unknown ratio σpnpnϕ/σppppϕ\sigma_{pn \to pn{\phi}}/{\sigma_{pp \to pp{\phi}}} has a weak effect on the A-dependence of the relative ϕ\phi meson production cross section at incident energy of present interest, whereas it is found to be appreciably sensitive to the phi in-medium width, which means that this relative observable can indeed be useful to help determine the above width from the direct comparison the results of our calculations with the future data from the respective ANKE-at-COSY experiment.Comment: 16 pages, 9 figure

    Analysis of the doubly heavy baryons in the nuclear matter with the QCD sum rules

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    In this article, we study the doubly heavy baryon states Ξcc\Xi_{cc}, Ωcc\Omega_{cc}, Ξbb\Xi_{bb} and Ωbb\Omega_{bb} in the nuclear matter using the QCD sum rules, and derive three coupled QCD sum rules for the masses, vector self-energies and pole residues. The predictions for the mass-shifts in the nuclear matter ΔMΞcc=1.11GeV\Delta M_{\Xi_{cc}}=-1.11\,\rm{GeV}, ΔMΩcc=0.33GeV\Delta M_{\Omega_{cc}}=-0.33\,\rm{GeV}, ΔMΞbb=3.37GeV\Delta M_{\Xi_{bb}}=-3.37\,\rm{GeV} and ΔMΩbb=1.05GeV\Delta M_{\Omega_{bb}}=-1.05\,\rm{GeV} can be confronted with the experimental data in the future.Comment: 10 pages, 4 figure

    Operator Product Expansion and Quark-Hadron Duality: Facts and Riddles

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    We review the status of the practical operator product expansion (OPE), when applied to two-point correlators of QCD currents which interpolate to mesonic resonances, in view of the violations of local quark-hadron duality. Covered topics are: a mini-review of mesonic QCD sum rules in vacuum, at finite temperature, or at finite baryon density, a comparison of model calculations of current-current correlation functions in 2D and 4D with the OPE expression, a discussion of meson distribution amplitudes in the light of nonperturbatively nonlocal modifications of the OPE, and a reorganization of the OPE which (partially) resums powers of covariant derivatives.Comment: now 68 pages, 29 figures (1 figure added), habilitation thesis, mild restructuring, typos corrected, about 30 references and corresponding text added, version to be published in Prog. Part. Nucl. Phy

    The Large Enriched Germanium Experiment for Neutrinoless Double Beta Decay (LEGEND)

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    The observation of neutrinoless double-beta decay (0νββ{\nu}{\beta}{\beta}) would show that lepton number is violated, reveal that neutrinos are Majorana particles, and provide information on neutrino mass. A discovery-capable experiment covering the inverted ordering region, with effective Majorana neutrino masses of 15 - 50 meV, will require a tonne-scale experiment with excellent energy resolution and extremely low backgrounds, at the level of \sim0.1 count /(FWHM\cdott\cdotyr) in the region of the signal. The current generation 76^{76}Ge experiments GERDA and the MAJORANA DEMONSTRATOR utilizing high purity Germanium detectors with an intrinsic energy resolution of 0.12%, have achieved the lowest backgrounds by over an order of magnitude in the 0νββ{\nu}{\beta}{\beta} signal region of all 0νββ{\nu}{\beta}{\beta} experiments. Building on this success, the LEGEND collaboration has been formed to pursue a tonne-scale 76^{76}Ge experiment. The collaboration aims to develop a phased 0νββ{\nu}{\beta}{\beta} experimental program with discovery potential at a half-life approaching or at 102810^{28} years, using existing resources as appropriate to expedite physics results.Comment: Proceedings of the MEDEX'17 meeting (Prague, May 29 - June 2, 2017

    The first search for bosonic super-WIMPs with masses up to 1 MeV/c2^2 with GERDA

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    We present the first search for bosonic super-WIMPs as keV-scale dark matter candidates performed with the GERDA experiment. GERDA is a neutrinoless double-beta decay experiment which operates high-purity germanium detectors enriched in 76^{76}Ge in an ultra-low background environment at the Laboratori Nazionali del Gran Sasso (LNGS) of INFN in Italy. Searches were performed for pseudoscalar and vector particles in the mass region from 60 keV/c2^2 to 1 MeV/c2^2. No evidence for a dark matter signal was observed, and the most stringent constraints on the couplings of super-WIMPs with masses above 120 keV/c2^2 have been set. As an example, at a mass of 150 keV/c2^2 the most stringent direct limits on the dimensionless couplings of axion-like particles and dark photons to electrons of gae<31012g_{ae} < 3 \cdot 10^{-12} and α/α<6.51024{\alpha'}/{\alpha} < 6.5 \cdot 10^{-24} at 90% credible interval, respectively, were obtained.Comment: 6 pages, 3 figures, submitted to Physical Review Letters, added list of authors, updated ref. [21
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