18,445 research outputs found
產甲烷條件下吲哚類有機物的降解途徑
Degradation of indole by an indole degrading methanogenic consortium enriched from sewage sludge proceeded through a two step hydroxylation pathway yielding oxindole and isatin. The ability of this consortium to hydroxylate and subsequently degrade substituted indoles was investigated. Of the substituted indoles tested, the consortium was able to transform or degrade 3 methylindole and 3 indolyl acetate. Oxindole, 3 methyloxindole, and indoxyl were identified as degradation metabolites of indole, 3 methylindole, and 3 indolyl acetate, respectively. Isatin (indole 2, 3 dione) was produced as an intermediate when the consortium was amended with oxindole, which provided the evidence that degradation of indole proceeded through successive hydroxylation of the 2 and 3 positions prior to ring cleavage between the C 2 and C 3 atoms on the pyrrole ring of indole. The presence of a methyl group ( CH 3 ) at either the 1 or 2 position of indole inhibited the initial hydroxylation reaction. The substituted indole, 3 methylindole, was hydroxylated at the 2 position but not at the 3 position and could not be further metabolized through the oxindole isatin pathway. Indoxyl (indole 3 one), the deacetylated product of 3 indolyl acetate, was not hydroxylated at the 2 position and thus was not further metabolized by the consortium. When an H atom or electron donating group (i.e., CH 3 ) was present at the 3 position, hydroxylation proceeded at the 2 position, but the presence of electron withdrawing substituent groups (i.e., OH or COOH) at the 3 position inhibited hydroxylation
An increase in under hydrostatic pressure in the superconducting doped topological insulator NbBiSe
We report an unexpected positive hydrostatic pressure derivative of the
superconducting transition temperature in the doped topological insulator \NBS
via SQUID magnetometry in pressures up to 0.6 GPa. This result is contrary
to reports on the homologues \CBS and \SBS where smooth suppression of is
observed. Our results are consistent with recent Ginzburg-Landau theory
predictions of a pressure-induced enhancement of in the nematic
multicomponent state proposed to explain observations of rotational
symmetry breaking in doped BiSe superconductors.Comment: 5 pages, 5 figure
Small atom diffusion and breakdown of the Stokes–Einstein relation in the supercooled liquid state of the Zr46.7Ti8.3Cu7.5Ni10Be27.5 alloy
Be diffusivity data in the bulk metallic glass forming alloy Zr46.7Ti8.3Cu7.5Ni10Be27.5 are reported for temperatures between 530 and 710 K, extending 85 K into the supercooled liquid state of the alloy. At the glass transition temperature Tg, a change in temperature dependence of the data is observed, and above Tg the diffusivity increases more quickly with temperature than below. The data in the supercooled liquid can be described by a modified Arrhenius expression based on a diffusion mechanism suggested earlier. The comparison with viscosity data in the supercooled liquid state of Zr46.7Ti8.3Cu7.5Ni10Be27.5 reveals a breakdown of the Stokes–Einstein relation, indicating a cooperative diffusion mechanism in the supercooled liquid state of Zr46.7Ti8.3Cu7.5Ni10Be27.5
On the contribution of twist-3 multi-gluon correlation functions to single transverse-spin asymmetry in SIDIS
We study the single spin asymmetry (SSA) induced by purely gluonic
correlation inside a nucleon, in particular, by the three-gluon correlation
functions in the transversely polarized nucleon, . This
contribution is embodied as a twist-3 mechanism in the collinear factorization
framework and controls the SSA to be observed in the -meson production with
large transverse-momentum in semi-inclusive DIS (SIDIS), . We define the relevant three-gluon correlation functions in
the nucleon, and determine their complete set at the twsit-3 level taking into
account symmetry constraints in QCD. We derive the single-spin-dependent cross
section for the -meson production in SIDIS, taking into account all the
relevant contributions at the twist-3 level. The result is obtained in a
manifestly gauge-invariant form as the factorization formula in terms of the
three-gluon correlation functions and reveals the five independent structures
with respect to the dependence on the azimuthal angle for the produced
meson. We also demonstrate the remarkable relation between the twist-3
single-spin-dependent cross section and twist-2 cross sections for the
-meson production, as a manifestation of universal structure behind the SSA
in a variety of hard processes.Comment: 8 pages, 2 figures. To appear in the proceedings of the 19th
International Spin Physics Symposium (SPIN2010), Juelich, Germany, Sept.27 -
Oct.2, 201
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