The cyclooxygenase (COX) product, prostacyclin (PGI2), inhibits platelet activation and vascular smooth-muscle cell migration and proliferation. Biochemically selective inhibition of COX-2 reduces PGI 2 biosynthesis substantially in humans. Because deletion of the PGI 2 receptor accelerates atherogenesis in the fat-fed low density lipoprotein receptor knockout mouse, we wished to determine whether selective inhibition of COX-2 would accelerate atherogenesis in this model. To address this hypothesis, we used dosing with nimesulide, which inhibited COX-2 ex vivo, depressed urinary 2,3 dinor 6-keto PGF 1␣ by approximately 60% but had no effect on thromboxane formation by platelets, which only express COX-1. By contrast, the isoform nonspecific inhibitor, indomethacin, suppressed platelet function and thromboxane formation ex vivo and in vivo, coincident with effects on PGI 2 biosynthesis indistinguishable from nimesulide. Indomethacin reduced the extent of atherosclerosis by 55 ؎ 4%, whereas nimesulide failed to increase the rate of atherogenesis. Despite their divergent effects on atherogenesis, both drugs depressed two indices of systemic inflammation, soluble intracellular adhesion molecule-1, and monocyte chemoattractant protein-1 to a similar but incomplete degree. Neither drug altered serum lipids and the marked increase in vascular expression of COX-2 during atherogenesis. Accelerated progression of atherosclerosis is unlikely during chronic intake of specific COX-2 inhibitors. Furthermore, evidence that COX-1-derived prostanoids contribute to atherogenesis suggests that controlled evaluation of the effects of nonsteroidal anti-inflammatory drugs and͞or aspirin on plaque progression in humans is timely. P latelet-dependent vascular occlusion complicating fracture of an atherosclerotic plaque is thought to be the pathophysiological basis of both acute myocardial infarction and the majority of cases of stroke (1, 2). The efficacy of plateletinhibitory drugs-aspirin (3-5), clopidogrel (6), and dipyridamole (7)-in the secondary prevention of coronary and cerebrovascular disease has been established in randomized controlled clinical trials. Much less is known about the potential contribution of platelet activation to development and progression of the underlying atherosclerotic disease. Although platelets release mitogenic growth factors and bioactive lipids when activated (8, 9), their relative absence in the descriptive morphology of atherosclerotic lesions in humans has led to a reduction in emphasis on their role in pathogenesis (10). Therefore, such studies do not address the possibility that platelets activated in the circulation of patients with atherosclerosis (11) might release products that modulate lesion progression, and controlled clinical trials of antiplatelet agents on plaque progression have not been performed. Similarly, mouse models of atherosclerosis seem quite resistant to spontaneous thrombosis (12), and it is unknown whether their development of vascular lesions alone results in platelet ac...

Four of nine tetraalkylammonium-based amino-acid ionic liquids prepared in this work show lower viscosities than all amino acid-based ionic liquids found in the literature and their reversible CO(2) absorption approaches 0.5 mol per mol ionic liquid.

The adsorption and activation of triplet O2 on the surface of nitrogen-doped carbon nanotube (NCNT) with different diameter and length were investigated. It was found that, rather than the unfavorable adsorption on normal carbon nanotube (CNT), the adsorption of O2 on NCNT was obviously exothermic and the electron transition of O2 happened in the adsorption process. The oxygen adsorbed on NCNT showed an interesting electron configuration which was similar to the active oxygen anion. The spin density, charge, and bond length of O2 changed with the size of NCNT. In combination with the recent results reported by Dai et al. (Science, 2009, 323, 760), it is reasonable to believe that these NCNTs should be a potential metal-free catalyst. The results presented here should be useful for designing and developing effective catalyst based on NCNT.

Measurements of permeability of sulfur dioxide (SO2) in five imidazolium-based ionic liquids supported on the polyethersulfone microfiltration membranes at temperatures from 25 to 45 degrees C and atmospheric pressure indicate that under the same conditions, the SO2 selectivity of separations using supported ionic liquid membranes are 9-19 times that of CO2.