1,493 research outputs found

    Cluster Model for Near-barrier Fusion Induced by Weakly Bound and Halo Nuclei

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    The influence on the fusion process of coupling transfer/breakup channels is investigated for the medium weight 6,7^{6,7}Li+59^{59}Co systems in the vicinity of the Coulomb barrier. Coupling effects are discussed within a comparison of predictions of the Continuum Discretized Coupled-Channels model. Applications to 6^{6}He+59^{59}Co induced by the borromean halo nucleus 6^{6}He are also proposed.Comment: 5 pages, 3 figures, FINUSTAR2 Conference, Aghios Nikolaus, Crete, Greece. 10-14 September 200

    A strong form of the Quantitative Isoperimetric inequality

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    We give a refinement of the quantitative isoperimetric inequality. We prove that the isoperimetric gap controls not only the Fraenkel asymmetry but also the oscillation of the boundary

    Neutron-skin thickness of 208^{208}Pb, and symmetry-energy constraints from the study of the anti-analog giant dipole resonance

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    The 208^{208}Pb(pp,nÎłpˉn\gamma\bar p) 207^{207}Pb reaction at a beam energy of 30 MeV has been used to excite the anti-analog of the giant dipole resonance (AGDR) and to measure its Îł\gamma-decay to the isobaric analog state in coincidence with proton decay of IAS. The energy of the transition has also been calculated with the self-consistent relativistic random-phase approximation (RRPA), and found to be linearly correlated to the predicted value of the neutron-skin thickness (ΔRpn\Delta R_{pn}). By comparing the theoretical results with the measured transition energy, the value of 0.190 ±\pm 0.028 fm has been determined for ΔRpn\Delta R_{pn} of 208^{208}Pb, in agreement with previous experimental results. The AGDR excitation energy has also been used to calculate the symmetry energy at saturation (J=32.7±0.6J=32.7 \pm 0.6 MeV) and the slope of the symmetry energy (L=49.7±4.4L=49.7 \pm 4.4 MeV), resulting in more stringent constraints than most of the previous studies.Comment: 6 pages, 5 figures. arXiv admin note: text overlap with arXiv:1205.232

    Guide For Recommended Practices To Perform Crack Tip Opening Displacement Tests In High Strength Low Alloy Steels

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    Fracture mechanics approach is important for all mechanical and civil projects that might involve cracks in metallic materials, and especially for those using welding as a structural joining process. This methodology can enhance not only the design but also the service life of the structures being constructed. This paper includes detailed consideration of several practical issues related to the experimental procedures to assess the fracture toughness in high strength low alloy steels (HSLA) using the crack tip opening displacement (CTOD) parameter, specifically pipeline steels for oil and gas transportation. These considerations are important for engineers who are new in the field, or for those looking for guidelines performing different procedures during the experimentation, which usually are difficult to understand from the conventional standards. We discuss on topics including geometry selection, number of replicate tests, fatigue precracking, test procedure selection and realization, reports of results and other aspects.213290302Colciencias [512]PetrobrasLNNano/CNPE

    Global transcriptome analysis reveals circadian regulation of key pathways in plant growth and development

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    Transcript abundance of roughly a third of expressed Arabidopsis thaliana genes is circadian-regulated

    Tissue-specific transcriptome analysis reveals candidate genes for terpenoid and phenylpropanoid metabolism in the medicinal plant ferula assafoetida

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    © 2019 ABRF. Methionine oxidation plays a critical role in many processes of biologic and biomedical importance, including cellular redox responses and stability of protein pharmaceuticals. Bottom-up methods for analysis of methionine oxidation can suffer from incomplete sequence coverage, as well as an inability to readily detect correlated oxidation between 2 or more methionines. However, the methodology for quantifying protein oxidation in top-down analyses is lacking. Previous work has shown that electron transfer dissociation (ETD)–based tandem mass spectrometry (MS/MS) fragmentation offers accurate and precise quantification of amino acid oxidation in peptides, even in complex samples. However, the ability of ETD-based MS/MS fragmentation to accurately quantify amino acid oxidation of proteins in a top-down manner has not been reported. Using apomyoglobin and calmodulin as model proteins, we partially converted methionines into methionine sulfoxide by incubation in H2O2. Using top-down ETD-based fragmentation, we quantified the amount of oxidation of various ETD product ions and compared the quantified values with those from traditional bottom-up analysis. We find that overall quantification of methionine oxidation by top-down MS/MS ranges from good agreement with traditional bottom-up methods to vast differences between the 2 techniques, including missing oxidized product ions and large differences in measured oxidation quantities. Care must be taken in transitioning ETD-based quantitation of oxidation from the peptide level to the intact protein level

    DNA‐Origami‐Templated Growth of Multilamellar Lipid Assemblies

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    Lipids are important building blocks in cellular compartments, and therefore their self‐assembly into well‐defined hierarchical structures has gained increasing interest. Cationic lipids and unstructured DNA can co‐assemble into highly ordered structures (lipoplexes), but potential applications of lipoplexes are still limited. Using scaffolded DNA origami nanostructures could aid in resolving these drawbacks. Here, we have complexed DNA origami together with a cationic lipid 1,2‐dioleoly‐3‐trimethylammonium‐propane (DOTAP) and studied their self‐assembly driven by electrostatic and hydrophobic interactions. The results suggest that the DNA origami function as templates for the growth of multilamellar lipid structures and that the DNA origami are embedded in the formed lipid matrix. Furthermore, the lipid encapsulation was found to significantly shield the DNA origami against nuclease digestion. The presented complexation strategy is suitable for a wide range of DNA‐based templates and could therefore find uses in construction of cell‐membrane‐associated components.acceptedVersionPeer reviewe

    Search for Fingerprints of Tetrahedral Symmetry in 156Gd^{156}Gd

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    Theoretical predictions suggest the presence of tetrahedral symmetry as an explanation for the vanishing intra-band E2-transitions at the bottom of the odd-spin negative parity band in 156Gd^{156}Gd. The present study reports on experiment performed to address this phenomenon. It allowed to determine the intra-band E2 transitions and branching ratios B(E2)/B(E1) of two of the negative-parity bands in 156Gd^{156}Gd.Comment: presented by Q.T. Doan at XLII Zakopane School of Physics: Breaking Frontiers: Submicron Structures in Physics and Biology, May 2008. 5 pages, minor corrections. To be published in the proceeding
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