Repeatability of corrosion parameters for titanium-molybdenum alloys in 0.9% NaCl solution

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Highly corrosion resistant siloxane-polymethyl methacrylate hybrid coatings

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Corrosion and Wear Studies of Cr3C2NiCr-HVOF Coatings Sprayed on AA7050 T7 Under Cooling

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

CNS-selective noncompetitive cholinesterase inhibitors derived from the natural piperidine alkaloid (-)-spectaline

LASSBio-767 [(-)-3-O-acetyl-spectaline] and LASSBio-822 [(-)-3-O-tert-Boc-spectaline] were recently described as cholinesterase inhibitors derived from the natural piperidine alkaloid (-)-spectaline, obtained from the flowers of Senna spectabilis (Fabaccae). We investigated their mechanism of inhibition of acetylcholinesterase and their efficacy in reversing scopolamine-induced amnesia. Competition assays with the substrate acetylthiocholine showed a concentration-dependent reduction in rat brain cholinesterase V-max without changes in apparent K-m. The kinetic data for LASSBio-767 and LASSBio-822 were best fit by a model of simple linear noncompetitive inhibition with K-i of 6.1 mu M and 7.5 mu M, respectively. A dilution assay showed a fast and complete reversal of inhibition, independent of incubation time. Simulated docking of the compounds into the catalytic gorge of Torpedo acetylcholinesterase showed interactions with the peripheral anionic site, but not with the catalytic triad. Anti-amnestic effects in mice were assessed in a step-down passive avoidance test and in the Morris water maze 30 min after injection of scopolamine (1 mg/kg i.p.). Saline, LASSBio-767, or LASSBio-822 was administered 15 min before scopolamine. Both compounds reversed the scopolamine-induced reduction in step-down latency at 0.1 mg/kg i.p. LASSBio-767 reversed scopolamine-induced changes in water maze escape latency at 1 mg/kg i.p. or p.o., while its cholinergic side effects were absent or mild up to 30 mg/kg i.p. (LD50 above 100 mg/kg i.p.). Thus, the (-)-spectaline derivatives are potent cholinergic agents in vivo, with a unique profile combining noncompetitive cholinesterase inhibition and CNS selectivity, with few peripheral side effects. (C) 2007 Elsevier B.V. All rights reserved.

Pyridine Alkaloids from Senna multijuga As Acetylcholinesterase Inhibitors

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Molecular Docking and Molecular Dynamic Studies of Semi-Synthetic Piperidine Alkaloids as Acetylcholinesterase Inhibitors

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Inhibitors of Clostridium histolyticum colagenase

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Inhibitors of human collagenase, MMP1

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

EFFECT OF THE ADDITION OF CR AND NB ON THE MICROSTRUCTURE AND ELECTROCHEMICAL CORROSION OF HEAT-TREATABLE AL-ZN-MG ALLOYS

The effect of the addition of Cr and Nb on the microstructure and the electrochemical corrosion of the weldable, high-strength and stress corrosion cracking (SCC) resistant Al-5%Zn-1.67%Mg-0.23%Cu alloy (H) has been studied. Combined additions of the alloying elements, J (with Nb), L (with Cr) and O (with Cr and Nb) and different heat treatments, ST (cold-rolled), A (annealed), F (quenched), B (quenched and aged) and C (quenched in two steps and aged), to obtain different microstructures and hardness have been performed. To correlate the electrochemical corrosion with the microstructure of the specimens, corrosion potential (E(cor)) measurements in different chloride solutions were performed and optical microscopy, SEM, TEM and EDX were applied. In chloride solutions containing dissolved O-2 or H2O2, the present alloys were polarized up to the pitting attack. It was shown that the E(cor) measurements were very sensitive to the alloy composition and heat treatment, increasing in the order H < J < L < O < Al (for a given heat treatment) and F < A approximate to ST < B < C (for a given alloy). The MgZn2 precipitates of the annealed (A) and cold-rolled (ST) specimens were dissolved in chloride solutions containing oxidizing agents and pitting attack was shown to develop in the cavities where the precipitates were present. In the specimens B and C, the compositions of the precipitate free zones was found to be equal to that of the matrix solid solution and preferential intergranular attack was not evident, this being in agreement with their SCC resistance. The addition of Cr and Nb increased the pitting corrosion resistance. The effects of Cr and Nb were additive, that of Cr being predominant, either, in the E(cor) shift or in the increase in the pitting corrosion resistance.

New selective acetylcholinesterase inhibitors designed from natural piperidine alkaloids

Five new piperidine alkaloids were designed from natural (-)-3-O-acetyl-spectaline and (-)-spectaline that were obtained from the flowers of Senna spectabilis (sin. Cassia spectabilis, Leguminosae). Two semi-synthetic analogues (7 and 9) inhibited rat brain acetylcholinesterase, showing IC50 of 7.32 and 15.1 mu M, and were 21 and 9.5 times less potent against rat brain butyrylcholinesterase, respectively. Compound 9 (1 mg/kg, ip) was fully efficacious in reverting scopolamine-induced amnesia in mice. The two active compounds (7 and 9) did not show overt toxic effects at the doses tested in vivo. (c) 2005 Elsevier Ltd. All rights reserved.