29 research outputs found

    Survival probability for high mass diffraction

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    Based on the calculation of survival probabilities, we discuss the problem of extracting the value of G3PG_{3P}, the triple Pomeron 'bare' coupling constant, by comparing the large rapidity gap single high mass diffraction data in proton-proton scattering and J/ΨJ/\Psi photo and DIS production. For p-p scattering the calculation in a three amplitude rescattering eikonal model, predicts the survival probability to be an order of magnitude smaller than for the two amplitude case. The survival probabilities calculation for photo and DIS J/ΨJ/\Psi production is made in a dedicated model. In this process we show that, even though its survival probability is considerably larger than in p-p scattering, its value is below unity and cannot be neglected in the data analysis. We argue that, regardless of the uncertainties in the suggested procedure, its outcome is important both with regards to a realistic estimate of G3PG_{3P}, and the survival probabilities relevant to LHC experiments.Comment: 17 pages, 8 pictures and one tabl

    Polyhydroxylated pyrrolidine and pyrrolizidine alkaloids from Hyancinthoides non-scripta and Scilla campanulata.

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    Aqueous ethanol extracts from the immature fruits and stalks of bluebell (Hyacinthoides non-scripta) were subjected to various ion-exchange column chromatographic steps to give 1,4-dideoxy-1,4-imino-D-arabinitol (1),2(R),5(R)-bis(hydroxymethyl)-3(R),4(R)-dihydroxypyrrolidine (DMDP) (2), 6-deoxy-6-C-(2,5-dihydroxyhexyl)-DMDP (3),2,5-dideoxy-2,5-imino-DL-glycero-D-manno-heptitol (homoDMDP)(4),homoDMDP-7-O-apioside (5), homoDMDP-7-O-beta-D-xylopyranoside (6), (1S*,2R*,3R*,5R*,7aR*)-1,2-dihydroxy-3,5- dihydroxymethylpyrrolizidine (7), and (1S*,2R*,3R*,5R*,6R*,7R*,7aR*)-3-hydroxymethyl-5-methyl-1,2,6,7 tetrahydroxypyrrolizidine (8). Bulbs of Scilla campanulata (Hyacinthaceae) yielded (1S*,2R*,3R*,5S*,7aR*)-1,2-dihydroxy-3,5-dihydroxy-methylpyrrol izidine (9) in addition to compounds 1-7. Compounds 3,6,7,8, and 9 are new natural products. Compound 4 is a potent competitive inhibitor with K(i) values of 1.5 microM for Caldocellum saccharolyticum beta-glucosidase and 2.2 microM for bovine liver beta-galactosidase. The 7-O-beta-D xyloside 6 was a stronger competitive inhibitor than 4 of C saccharolyticum beta-glucosidase and rat intestinal lactase, with K(i) values of 0.06 and 0.07 microM, respectively, but a weaker inhibitor of bovine liver beta-galactosidase. Furthermore, compound 4 is also a competitive inhibitor (K(i) = 1.8 microM) of porcine kidney trehalase, but 6 was inactive against this enzyme

    Exo-Arabinanase of Penicillium chrysogenum Able To Release Arabinobiose from α-1,5-l-Arabinan

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    An exo-arabinanase, designated Abnx, was purified from a culture filtrate of Penicillium chrysogenum 31B by ammonium sulfate precipitation, anion-exchange chromatography, and hydrophobic chromatography. Abnx had an apparent molecular mass of 47 kDa. The enzyme released only arabinobiose from the nonreducing terminus of α-1,5-l-arabinan and showed no activity towards p-nitrophenyl-α-l-arabinofuranoside and α-1,5-l-arabinofuranobiose. Abnx is the first enzyme with this mode of action
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