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11.
Condensation of 5-(p-nitrophenyl)-2-pentanone with phenylbiguanide hydrochloride (V) gave a 2-methyl-2-(p-nitrophenylpropyl)-1,2-dihydro-s-triazine (IX); hydrogenation of the nitro group to amino followed by bromoacetylation afforded the candidate irreversible inhibitor of dihydrofolic reductase, namely, 2-(p-bromoacetamidophenylpropyl)-4,6-diamino-1,2-dihydro-2-methyl-s-triazine hydrochloride (VIII). Similarly, the o, m, and p-isomers of 5-nitrophenoxy-2-pentanone were converted to the corresponding 2-(bromoacetamidophenoxypropyl)-1,2-dihydro-s-triazines (XI). The four candidate irreversible inhibitors were evaluated on the dihydrofolic reductases from pigeon liver, Walker-256 rat tumor, and L-1210/FR8 mouse leukemia. Only VIII was an irreversible inhibitor; VIII slowly inactivated the L-121-/FR8 mouse leukemia enzyme with a half-life of 2–3 hours at 37°, but VIII showed no inactivation of the other two dihydrofolic reductases—a species specific inactivation. 相似文献
12.
Reaction of the cationic complex [WI(CO)(NCMe){Ph2P(CH2)PPh2}(η2-MeC2ME)][BF4] with an equimolar amount of MX (MX = NaCl, NaBr, NaI, KNO2, KNO3, NaNCS or KOH) in acetone at room temperature gave the neutral complex [WIX(CO){Ph2P(CH2)PPh2}(η2-MeC2Me)] (1–7) in good yield. Complexes 1–7 have been characterized by elemental analysis (C, H and N), IR and 1H NMR spectroscopy. 相似文献
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J. D. Baker R. J. Gehrke R. C. Greenwood D. H. Meikrantz 《Journal of Radioanalytical and Nuclear Chemistry》1982,74(1-2):117-124
A microprocessor-controlled radiochemical separation system, which has been developed at the INEL, has been further advanced
to separate individual rare-earth elements from mixed fission products in times of a few minutes. The system was composed
of an automated chemistry system fed by two ∼300μg252Cf sources coupled directly by a He-jet to transport the fission products. Chemical separations were performed using two high
performance liquid chromatography columns coupled in series. The first column separated the rare-earth group by extraction
chromatography using dihexyldiethylcarbamoylmethylphosphonate (DHDECMP) adsorbed on Vydac C8 resin. The second column isolated the individual rare-earth elements by cation exchange chromatography using Aminex A-9 resin
with α-hydroxyisobutyric acid (α-HIBA) as the eluent. Significant results, which have been obtained to date with this advanced
system, are the identification of several new neutron-rich rare-earth isotopes including155Pm (T=48±4 s) and163Gd (T=68±3 s). In addition a half-life of 41±4 s is reported for160Eu.
Work supported by the U.S. Department of Energy under DOE Contract No. De-ACO7-76IDO-1570. 相似文献
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The metal binding properties of the dinucleotide duplex, dCG x dCG, were analyzed in the gas phase with ion mobility mass spectrometry. Both MALDI and ESI were used to generate [M(dCG x dCG)]+ complexes. The collision cross section of each complex was measured in helium using ion mobility based methods and compared to calculated cross sections of theoretical structures. When metal cations classified as hard acids were combined with dCG x dCG, the [M(dCG x dCG)]+ complex organized into a globular structure. However, when soft acid metal cations were examined, a structure was observed where the two C-G base pairs were Watson-Crick bound. 相似文献
17.
Max O. D. G. Baker Nirukshan Shanmugam Chi L. L. Pham Sarah R. Ball Emma Sierecki Yann Gambin Megan Steain Margaret Sunde 《Molecules (Basel, Switzerland)》2022,27(11)
TIR-domain-containing adapter-inducing interferon-β (TRIF) is an innate immune protein that serves as an adaptor for multiple cellular signalling outcomes in the context of infection. TRIF is activated via ligation of Toll-like receptors 3 and 4. One outcome of TRIF-directed signalling is the activation of the programmed cell death pathway necroptosis, which is governed by interactions between proteins that contain a RIP Homotypic Interaction Motif (RHIM). TRIF contains a RHIM sequence and can interact with receptor interacting protein kinases 1 (RIPK1) and 3 (RIPK3) to initiate necroptosis. Here, we demonstrate that the RHIM of TRIF is amyloidogenic and supports the formation of homomeric TRIF-containing fibrils. We show that the core tetrad sequence within the RHIM governs the supramolecular organisation of TRIF amyloid assemblies, although the stable amyloid core of TRIF amyloid fibrils comprises a much larger region than the conserved RHIM only. We provide evidence that RHIMs of TRIF, RIPK1 and RIPK3 interact directly to form heteromeric structures and that these TRIF-containing hetero-assemblies display altered and emergent properties that likely underlie necroptosis signalling in response to Toll-like receptor activation. 相似文献
18.
Ahlen S Ambrosio M Antolini R Auriemma G Baker R Baldini A Bam BB Barbarino GC Barish BC Battistoni G Bellotti R Bemporad C Bernandini P Bilokon H Bisi V Bloise C Bower C Bussino S Cafagna F Calicchio M Campana D Campana P Carboni M Cecchini S Cei F Chiarella V Cormack R Corona A Coutu S De Cataldo G Dekhissi H De Marzo C De Vincenzi M Di Credico A Diehl E Erriquez O Favuzzi C Ficenec D Forti C Fusco P Giacomelli G Giannini G Giglietto N Giubellino P Grassi M Green P Grillo A Guarino F 《Physical review letters》1994,72(5):608-612
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The use of numerical models has greatly increased our understanding of the electrical and microphysical process within electrified clouds. We use the University of Washington, 1.5-dimensional thunderstorm model to examine the effects of including a runaway electron based lightning initiation mechanism. We find that this mechanism can significantly alter the electrification history of modeled storms and produce vertical electric field profiles that are very similar to those of observed storms. To cite this article: R. Solomon et al., C. R. Physique 3 (2002) 1325–1333. 相似文献