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31.
Farias WR Lima PC Rodrigues NV Siqueira RC Amorim RM Pereira MG Assreuy AM 《Natural product communications》2011,6(6):863-866
Sulfated polysaccharides (SP) of brown algae (Phaeophyta) are composed mainly of alpha- L-fucose, being classified as fucans, with recognized role in inflammation but not in nociception, which was already described for SP obtained from red algae. Here the SP of the brown marine alga S. schroederi (named Ss-SP) was isolated and assayed for the antinociceptive effect. Ss-SP was isolated by DEAE-cellulose, analyzed by agarose gel electrophoresis and evaluated in nociception models (Formalin, Hot plate, Von Frey) using Swiss mice (20-25g). Anion exchange chromatography provided four major fractions being F1 (Ss-SP) that of highest metachromatic activity and sugar content. Ss-SP inhibited both phases of the formalin test. In the first phase the paw licking (55.2 +/- 8.07s) was reduced by 45% (30.5 +/- 6.51s) and 40% (32.85 +/- 8.66s) at 0.1 and 1 mg/kg, respectively. In the second phase, Ss-SP was also inhibitory about 39%, but only at 1 mg/kg (83.0 +/- 15.70s) compared to formalin (136.8 +/- 10.27s). This inhibitory effect suggests a mixed mechanism similar to morphine, which was not confirmed in the hot plate test, a model of pain associated with central neurotransmission. However, Ss-SP reduced the animal reaction in response to stimulation withVon Frey filament at the 2nd and 3rd h (20.8 +/- 6.86% versus carrageenan: 47.9 +/- 5.83%; 33.3 +/- 7.71% versus carrageenan: 62.5 +/- 9.83%). Accordingly, the paw edema induced by carrageenan (0.08 +/- 0.01g) was potently reduced in 45.35% by Ss-SP pre-treatment (0.02 +/- 0.003g), corroborating the anti-inflammatory activity demonstrated for brown seaweed polysaccharides. In conclusion our data revealed for the first time the antinociceptive effect of Ss-SP which could be used as a new source of analgesic substances. 相似文献
32.
In this work new polymer/carrier composites are described which serve as novel materials in flow-through reactors for polymer-supported organic solution-phase synthesis. Monolithic polymer/carrier columns are prepared by a new precipitation polymerization process inside the void pore volume of megaporous glass carrier materials. Chemical functionalization of the internal polymer phase with chlorosulfonic acid or trimethylamine generates small, interconnected ion-exchange resin beads with a diameter of 1-3 microm which can be used for a large variety of organic syntheses. These monolithic rods are incorporated into an appropriate casing and can conveniently be operated in the flow-through mode. Important successful applications are polymer-assisted solution-phase reductions, oxidations and Horner-Emmons olefinations. Additionally, the use of these monolithic columns as catalytic microreactors and their performance in selected reactions are described. 相似文献
33.
The oxidation of carbon monoxide on a Pt(110) surface is considered as a medium for chemical information processing in which bits of information are represented by traveling pulses of high oxygen coverage. Using numerical simulations for a model of CO oxidation we demonstrate that in such system one dimensional chemical signal diode can be realized by setting a proper profile of temperature. We also show that a pulse splitting can occur on a temperature inhomogeneity. The phenomenon of pulse splitting can be used to construct one dimensional generator of a train of pulses with adjustable frequency. 相似文献
34.
Wet-etching fabrication of multilayer GaAlAs/GaAs microtips for scanning near-field optical microscopy 总被引:1,自引:0,他引:1
S. Khalfallah C. Gorecki J. Podlecki M. Nishioka H. Kawakatsu Y. Arakawa 《Applied Physics A: Materials Science & Processing》2000,70(2):223-225
We propose to fabricate GaAlAs/GaAs multilayer microtips for scanning near-field optical microscopy (SNOM) using anisotropic etching. The etching was performed in a solution of H3PO4:H2O2:H2O operating at a temperature of 10 °C. We obtained pyramid-shaped microtips with four etched facets and with a radius of curvature at the apex that was lower than 50 nm. 相似文献
35.
Let be a discrete subgroup of SL(2,
) with a fundamental region of finite hyperbolic volume. (Then, is a finitely generated Fuchsian group of the first kind.) Let
0}} {a(n)e^{2\pi i(n + {\kappa })z/{\lambda }} } ,{ }z \in \mathcal{H}.$$
" align="middle" border="0">
be a nontrivial cusp form, with multiplier system, with respect to . Responding to a question of Geoffrey Mason, the authors present simple proofs of the following two results, under natural restrictions upon .
Theorem.
If the coefficients a(n) are real for all n, then the sequence {a(n)} has infinitely many changes of sign.
Theorem.
Either the sequence {Re a(n)} has infinitely many sign changes or Re a(n) = 0 for all n. The same holds for the sequence {Im a(n)}. 相似文献
36.
Fluorescence recovery after pattern photobleaching is used to measure the self-diffusion of surfactant molecules, along cylinders and perpendicular to their main axis in an oriented hexagonal lyotropic phase. Unexpectedly, while the motion along cylinders is diffusive, a superdiffusive behavior is observed in the direction perpendicular to the cylinder axis. Moreover, varying the lattice parameter, we found that the perpendicular diffusion time is governed only by the number of cylinders to cross, providing experimental evidence for superdiffusion with a bounded step length. 相似文献
37.
38.
An aporphine alcaloid of the bulbocapnine-type (isocorydine) was used for the synthesis of aristolochic acid analogs. By degradation and nitration of the reaction product three new compounds, a dinitrophenanthrene, a nitro- and a dinitrophenanthrene acid were obtained and their structures were established. 相似文献
39.
Wladimir Skinder 《Analytical and bioanalytical chemistry》1912,51(10-11):670-671
40.