55,346 research outputs found
Evidence for the decay B0→J/ψω and measurement of the relative branching fractions of meson decays to J/ψη and J/ψη′
No full textFirst 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)
Delayed winter warming: A robust decadal response to strong tropical volcanic eruptions?
No full textClimate simulations suggest that strong tropical volcaniceruptions (SVEs) induce decadal dynamical responses in thecoupled ocean‐atmosphere system, which protract theclimate recovery beyond the short‐lived radiative forcing.Here, for the first time, we diagnose the signature of suchresponses in European seasonal climate reconstructions overthe past 500 years. The signature consists of a decadal‐scalepositive phase of the winter North Atlantic Oscillationaccompanied by winter warming over Europe peakingapproximately one decade after a major eruption. Thereconstructed delayed winter warming is compatible withformerly suggested mechanisms behind simulated SVE‐driven climate responses, thus corroborating the existence ofSVE‐driven decadal climate variability. Historical climate‐state uncertainty may, however, hamper unambiguousstatistical and dynamical assessments both for multiple andfor individual SVEs. Citation: Zanchettin Davide, TimmreckClaudia, Bothe Oliver, Lorenz Stephan J., Hegerl Gabriele, GrafHans‐F., Luterbacher Jürg, Jungclaus Johann H., (2012), Delayedwinter warming: A robust decadal response to strong tropicalvolcanic eruptions
Stephan, Hermina (Death, 1908-08-29)
No full textAddress: 2524 W. 6th St.Age at death: 69 Yrs. 2mos 23 days464/Pg.103/1908/F W W/B.P.- Germany/Dr. Wm. Stephan/John J. Radel Co./Spring Grove Cem.Original record filed in drawer labeled 'STEINS-STEWART'
Catalytic P-H activation by Ti and Zr catalysts
No full textCatalytic dehydrocoupling of phosphines was investigated using the anionic zirconocene trihydride salts [Cp*Zr-2(mu-H)(3)Li](3) (1a) or [Cp*Zr-2(mu-H)(3)K(thf)(4)] (1b), and the metallocycles [CpTi(NPtBu3)(CH2)(4)] (6) and [Cp*M(NPtBu3)(CH2)(4)] (M = Ti 20, Zr 21) as catalyst precursors. Dehydrocoupling of primary phosphines RPH2 (R = Ph, C6H2Me3, Cy, C10H7) gave both dehydrocoupled dimers RP(H)P(H)R or cyclic oligophosphines (RP)(n) (n = 4, 5) while reaction of tBu(3)C(6)H(2)PH(2) gave the phosphaindoline tBu(2)(Me2CCH2)C6H2PH (9). Stoichiometric reactions of these catalyst precursors with primary phosphines afforded [Cp*Zr-2((PR)(2))H][K(thf)(4)] (R = Ph 2, Cy 3, C6H2Me3 4), [Cp*Zr-2((PPh)(3))H] [K(thf)(4)] (5), [CpTi(NPtBu3)(PPh)(3)] (7) and [CpTi(NPtBu3)(mu-PHPh)](2) (8), while reaction of 6 with (C(6)H(2)tBu3)PH2 in the presence of PMe3 afforded [CpTi(NPtBu3)(PMe3)(p(C(6)H(2)tBu(3))] (10). The secondary phosphines Ph2PH and (PhHPCH2)(2)CH2 also undergo dehydrocoupling affording (Ph2P)(2) and (PhPCH2)(2)CH2. The bisphosphines (CH2PH2)(2) and C6H4(PH2)(2) are dehydrocoupled to give (PCH2CH2PH)(2) (12) and (C6H4P(PH))(2) (13) while prolonged reaction of 13 gave (C6H4P2)(8) (14). The analogous bisphosphine Me2C6H4(PH)(2) (17) was prepared and dehydrocoupling catalysis afforded (Me2C6H2P(PH))(2) (18) and subsequently [(Me2C6H2P2)(2)(mu-Me2C6H2P2)](2) (19). Stoichiometric reactions with these bisphosphines gave [Cp*Zr-2(H)(PH)(2)C6H4] [Li(thf)(4)] (22), [Cp*Ti(NPtBu3)(PH)(2)C6H4](2) (23) and [Cp*Ti(NPtBu3)(PH)(2)C6H4] (24). 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Den frölich erlebten Neun und Vierzigsten Geburtstag, des Hochehrwürdigen und Hochgelahrten Herrn, Herrn M. Stephan Schultz, der Gemeinde zu St. Ulrich in Halle hochverdienten Lehrers, als solcher den 6ten Hornung 1762 einfiel, feierten zur Bezeugung ihrer Ergebenheit / Deroselben treugehorsamste Verehrer J. G. Burgmann, aus dem Mecklenburgischen. F. H. Callenberg, aus Halle. B. C. H. Giesebrecht, a. d. Mecklenburgischen. C. F. Hesse, aus der Mittelmarck. J. M. Meuter, aus Francken. C. L. Rosenow, aus Pommern.
No full textGlückwunsch auf Stephan Schultz, Lehrer, zum 49. Geburtstag, 6. Febr. 1762Autopsie nach dem Exemplar der ULB Sachsen-AnhaltVorlageform des Erscheinungsvermerks: Halle, gedruckt mit Schneiderschen Schriften. - Erscheinungsjahr nach der Datierung im Tite
[Newspaper Clipping: Author Claims Evidence of Second JFK Assassin #1]
No full textNewspaper article titled "Author Claims Evidence of Second JFK Assassin." The article states that author Richard J. Whalen concluded "that there is circumstantial evidence to support the theory of a second assassin in the shooting of President John F. Kennedy.
Towards NMR analysis of the HIV-1 coreceptor CCR5 and its interaction with RANTES
No full textCCR5 is a chemokine receptor together with CD4 used by HIV-1 as a primary gate of cell infection. For this reason CCR5 is of great interest for medicine as a target for the anti-HIV-1 therapies. Since the binding site of its endogenous ligand RANTES overlaps with the binding site of viral envelope glycoprotein gp120, a noninflamatory RANTES derivative 5P12-RANTES has been developed as an anti-HIV-1 infection microbicide. The primary aim of this thesis was to establish an NMR-amenable system to study CCR5 and to understand better the interaction with RANTES.
For this purpose CCR5 expressed in insect cells was characterized in detail with regards to its secondary structure, oligomeric state, particle size, stability, posttranslational modifications and functionality. In contrast to the previous results, carefully performed detergent screening revealed that FosCholine-12, a detergent which allows high yield purification, does not support CCR5 recognition by 2D7 and cannot be used for studying CCR5 interactions with ligands. Therefore for the functional studies the receptor was solubilized with a milder detergent mixture DDM/CHAPS/CHS, which was shown to support native CCR5 tertiary structure.
Using this setup it could be shown by SPR that 5P12-RANTES binds with higher affinity than another potent RANTES variant PSC-RANTES (Morin et al., manuscript in preparation). This explains why 5P12-RANTES, which unlike PSC-RANTES does not cause CCR5 internalization, is an equally effective anti-HIV-1 microbicide. On the other hand, the wild-type RANTES was shown to aggregate on the receptor micelle using a mechanism compatible with the linear oligomerization, a process that is proposed to serve local chemokine preconcentration.
To obtain an access to a cost-efficient source of isotope-labeled samples, an E. coli expression system was established for CCR5 (Wiktor et al., 2012, J Biomol NMR, in revision). The expression was facilitated by fusing the N-terminus of CCR5 to well expressing protein domains e.g. thioredoxin. The C-terminal CCR5 truncation and the mutation of cysteines increased the protein yield up to 10 mg/L and improved the sample stability. Due to the engineered thrombin proteolytic site the N-terminal fusion partner i.e. thioredoxin could be quantitatively cleaved and removed by size exclusion chromatography. The FC-12-purified receptor was abundant in alpha-helical secondary structure but could bind RANTES, MIP-1beta and conformation-dependent antibody 2D7 only when solubilized by a DDM/CHAPS/CHS mixture. Using 15N,13C,2H-labeled CCR5 2D and 3D NMR experiments were recorded but only about 80 backbone resonances could be resolved. The spectral quality was jeopardized by large overlap and line-broadening and needs further improvements to allow the assignment and the structural investigation.
To study 5P12-RANTES by NMR the backbone assignment was completed. The HSQC spectrum revealed that, unlike wild-type RANTES and other chemokines, 5P12-RANTES does not form dimers. The secondary chemical shift analysis suggest that the overall structure of 5P12-RANTES is similar to the wild-type RANTES, with the exception of the mutated N-terminus, which does not participate in the intermolecular beta-sheet and was shown to be highly flexible. Another important observation was that RANTES secondary structure is perturbed by Fos-Choline detergents, whereas maltosides shift the RANTES monomer:dimmer equilibrium towards its monomeric form.
The last part of the thesis present an independent study, where using ubiquitin as an example the mechanism of protein unfolding is studied (Vajpai et al., 2012, Proc Natl Acad Sci USA, in revision) manuscript submitted for publication). The secondary chemical shift analysis showed that the alcohol-denatured ubiquitin structure closely resembles the cold- and pressure denatured structure. This suggests that alcohol, low temperature and pressure unfold proteins by reducing the hydrophobic effect, the cost of exposing hydrophobic residues.
The data of this thesis will be presented in the following publications:
1. Wiktor, M., Morin, S., Sass, H-J., Kebbel, F., Grzesiek, S. (2012) Biophysical and structural investigation of bacterially expressed and engineered CCR5, a G protein-coupled receptor. J Biomol NMR (2012, in revision).
2. Vajpai, N., Nisius, L., Wiktor, M., Grzesiek, S. (2012) High pressure NMR reveals close similarity between cold and alcohol protein denaturation due to a reduction of the hydrophobic effect. Proc Natl Acad Sci USA (in revision).
3. Morin, S., Wiktor, M., Sass, H-J., Hartley, O., Grzesiek, S. (2012) Modulation of RANTES binding to CCR5 by modifications in the N-terminus and C-terminus (in preparation)
Measurement of the CP-violating phase \phi s in Bs->J/\psi\pi+\pi- decays
No full textMeasurement of the mixing-induced CP-violating phase phi_s in Bs decays is of prime importance in probing new physics. Here 7421 +/- 105 signal events from the dominantly CP-odd final state J/\psi pi+ pi- are selected in 1/fb of pp collision data collected at sqrt{s} = 7 TeV with the LHCb detector. A time-dependent fit to the data yields a value of phi_s=-0.019^{+0.173+0.004}_{-0.174-0.003} rad, consistent with the Standard Model expectation. No evidence of direct CP violation is found
Prinz, Stephan, Juristische Embleme: Rechtsmotive in der Emblematik des 16. und 17. Jahrhunderts (Recht und Gesellschaft 6) Münster 2009
No full textArlinghaus F-J. Prinz, Stephan, Juristische Embleme: Rechtsmotive in der Emblematik des 16. und 17. Jahrhunderts (Recht und Gesellschaft 6) Münster 2009. Zeitschrift für Neuere Rechtsgeschichte. 2012;34:301-302
Figures 22–25. Tergum 8 in Stick-tight fleas in the nostrils and below the tongue: evolution of an extraordinary infestation site in Hectopsylla (Siphonaptera: Pulicidae)
No full textFigures 22–25. Tergum 8 and sensilium in Hectopsylla females. Fig. 22. H. narium sp. nov. (paratype). Fig. 23.Published as part of Blank, Stephan M., Kutzscher, Christian, Masello, Juan F., Pilgrim, Robert L. C. & Quillfeldt, Petra, 2007, Stick-tight fleas in the nostrils and below the tongue: evolution of an extraordinary infestation site in Hectopsylla (Siphonaptera: Pulicidae), pp. 117-137 in Zoological Journal of the Linnean Society 149 (1) on page 132, DOI: 10.1111/j.1096-3642.2006.00239.x, http://zenodo.org/record/542762
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