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81.
Puebla P Oshima-Franco Y Franco LM Santos MG Silva RV Rubem-Mauro L Feliciano AS 《Molecules (Basel, Switzerland)》2010,15(11):8193-8204
The effect of four sub-extracts prepared from the lyophilized hydroalcoholic bark of Dipteryx alata (Leguminosae-Papilionoideae) dissolved in a methanol-water (80:20) mixture through a liquid-liquid partition procedure has been investigated against the neuromuscular blockade of the venom of the snake Bothrops jararacussu. The active CH?Cl? sub-extract has been extensively analyzed for its chemical constituents, resulting in the isolation of four lupane-type triterpenoids: lupeol, lupenone, 28-hydroxylup-20(29)-en-3-one, betulin, nine isoflavonoids: 8-O-methylretusin, 7-hydroxy-5,6,4'-trimethoxyisoflavone, afrormosin, 7-hydroxy-8,3',4'-trimethoxyisoflavone, 7,3'-dihydroxy-8,4'-dimethoxyisoflavone, odoratin, 7,8,3'-trihydroxy-4'-methoxyisoflavone, 7,8,3'-trihydroxy-6,4'-dimethoxyisoflavone, dipteryxin, one chalcone: isoliquiritigenin, one aurone: sulfuretin and three phenolic compounds: vanillic acid, vanillin, and protocatechuic acid. Their chemical structures were elucidated on the basis of spectroscopic analysis, including HRMS, 1D- and 2D-NMR techniques. 相似文献
82.
Ghosh S Carty D Clarke SP Corr SA Tekoriute R Gun'ko YK Brougham DF 《Physical chemistry chemical physics : PCCP》2010,12(42):14009-14016
We report the physico-chemical characterisation of fatty acid stabilised aqueous magnetic fluids, which are ideal systems for studying the influence of nanoparticle aggregation on the emergent magnetic resonance properties of the suspensions. Stable colloids of superparamagnetic magnetite, Fe(3)O(4), nanoparticle clusters in the 80 to 100 nm size range were produced by in situ nanoparticle growth and stabilisation, and by suspending pre-formed nanoparticles. NMR relaxation analysis shows that the magnetic resonance properties of the two types of suspension differ substantially and provides new insights into how the relaxation mechanisms are determined by the organisation of the nanoparticles within the clusters. 相似文献
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A fast full second order time-step algorithm for some recently proposed nonlinear, nonlocal active models for the inner ear is analyzed here. In particular, we emphasize the properties of discretized systems and the convergence of a hybrid direct-iterative solver for its approximate solution in view of the parameters of the continuous model. We found that the proposed solver is faster than standard sparse direct solvers for all the considered discrete models.Numerical tests confirm that the proposed techniques are crucial in order to get fast and reliable simulations. 相似文献
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In order to evaluate its relevance, we reconsider critically the recent proposal by Leggett and Garg to test macrorealism
against quantum mechanics by resorting to experiments involving noninvasive measurement processes on a SQUID. Our conclusion
is that, in spite of the fact that the proposed experiment would neither constitute a test of macrorealism nor a test of macrocontextuality,
a simplified form of it represents a (presumably) feasible experiment permitting a direct test of macroscopic quantum coherence.
We also analyze the proposal from the point of view of the recent attempts to build up model theories allowing to take, within
a purely quantum framework, a macrorealistic position about natural phenomena, i.e., the socalled dynamical reduction models
and we stress that the proposed experiment has no relevance for the dynamical reduction program, as developed so far. However
consideration of the SQUID system allows one to test other possible dynamical mechanisms leading to the objectification of
macroproperties which could, in principle, be operative. We also briefly sketch experimental procedures to be followed to
get all relevant information concerning macrocoherence. 相似文献
89.
Regan J. Anderson Benjamin J. Compton Ching-wen Tang Astrid Authier-Hall Colin M. Hayman Gene W. Swinerd Renata Kowalczyk Paul Harris Margaret A. Brimble David S. Larsen Olivier Gasser Robert Weinkove Ian F. Hermans Gavin F. Painter 《Chemical science》2015,6(9):5120-5127
It is known that T cells can eliminate tumour cells through recognition of unique or aberrantly expressed antigens presented as peptide epitopes by major histocompatibility complex (MHC) molecules on the tumour cell surface. With recent advances in defining tumour-associated antigens, it should now be possible to devise therapeutic vaccines that expand specific populations of anti-tumour T cells. However there remains a need to develop simpler efficacious synthetic vaccines that possess clinical utility. We present here the synthesis and analysis of vaccines based on conjugation of MHC-binding peptide epitopes to α-galactosylceramide, a glycolipid presented by the nonpolymorphic antigen-presenting molecule CD1d to provoke the stimulatory activity of type I natural killer T (NKT) cells. The chemical design incorporates an enzymatically cleavable linker that effects controlled release of the active components in vivo. Chemical and biological analysis of different linkages with different enzymatic targets enabled selection of a synthetic vaccine construct with potent therapeutic anti-tumour activity in mice, and marked in vitro activity in human blood. 相似文献
90.
Rafael C. Machado Richard M. Grazul Renata Diniz 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(7):564-569
In the solid state, crystals of both 1‐(7‐chloro‐1,4‐dihydroquinolin‐4‐ylidene)thiosemicarbazide–methanol–water (2/1/1), 2C10H9ClN4S·CH3OH·H2O, (I), and its hydrochloride salt {systematic name: [(7‐chloro‐1,4‐dihydroquinolin‐4‐ylidene)azaniumyl]thiourea chloride}, C10H10ClN4S+·Cl−, (II), assume the imine tautomeric form, contrary to other 4‐amino‐7‐chloroquinolines. Of particular interest are the N—C bond lengths, which have appreciable double‐bond character, and the C—N—C aromatic ring bond angle. Both of these parameters have been studied extensively in 4‐amino‐substituted quinolines. The crystal structures of (I) and (II) in this study provide interesting examples of the amino–imino tautomerism which exists in this class of compound and is, to the best of our knowledge, hitherto unreported. 相似文献