Solid-liquid equilibria of multicomponent lipid mixtures under CO2 pressure: Measurement and thermodynamic modeling

A method for evaluating solid-liquid equilibria of mixtures of lipids and carbon dioxide (CO2) under pressure is developed and presented in this article. Experimental measurements by high-pressure differential scanning calorimetry (DSC) are performed to determine solid-liquid transition temperatures as a function of composition. These data are used to develop a simplified approach for thermodynamic modeling, i.e. correlation and prediction, of the solid-liquid equilibria. The model requires fewer pure component properties in comparison with cubic equations of state: the solid-state fugacity is determined with reference to the subcooled liquid state while regular solution theory is applied for the calculation of liquid-phase activity coefficients. Application of the model is demonstrated for mixtures of ceramide 3A and cholesterol in compressed CO2 in the range of pressure from 0.1 to 6.1 MPa. A satisfactory correlation of solid-liquid equilibria is obtained for binary systems consisting of either the lipid mixture or one lipid in compressed CO2. With the fitted binary interactions parameters, the eutectic temperature of the ternary mixture is predicted to within 1\ub0C of the experimental value in the range of pressure considered. The proposed evaluation method looks sufficiently accurate for representing multiphase equilibria of lipid mixtures in compressed CO2 and has direct application to gas-assisted micronization processes such as PGSS (Particles from Gas-Saturated Solution)

Catalytic chain transfer polymerization of methyl methacrylate in supercritical carbon dioxide: Evidence for a diffusion-controlled transfer process

The mechanism of catalytic chain transfer polymerization with methyl methacrylate was studied in a range of media. The chain transfer reaction in supercritical CO2 was found to be significantly enhanced compared with similar experiments in toluene or in bulk methyl methacrylate. The results are consistent with a diffusion-controlled rate-determining step in the transfer process with cobaloxime catalysts. The gaslike viscosities in the supercritical medium result in an approximate chain transfer coefficient (k(tr)) of 10(8) L mol(-1) s(-1): an order of magnitude higher than values obtained in conventional organic solvents

Reversible addition-fragmentation chain transfer polymerization of methyl methacrylate in suspension

The reversible addition-fragmentation chain transfer polymerization of methyl methacrylate mediated by 2-cyanoprop-2-yl dithiobenzoate (CPDB) in bulk (60 and 70 degrees C) and suspension (70 degrees C) was studied, and in both polymerization systems, a good control of the molecular weight and polydispersity was observed. Stable suspension polymerizations were carried out over a range of CPDB concentrations, and with increasing CPDB concentration, the particle size and polydispersity index of the produced polymer decreased. The former was ascribed to the lower viscosities of the monomer and polymer droplets at low conversions, which caused easier breakup with the applied shear stresses. Lower polydispersity indices at higher CPDB concentrations were probably caused by a diminished gel effect, which was observed at lower CPDB concentrations at high conversions, causing a broadening of the molecular weight distribution. The livingness of the polymers formed in suspension was proven by successful chain extensions with methyl methacrylate, styrene, and 2-hydroxyethyl methacrylate. (c) 2005 Wiley Periodicals, Inc

Size-tunable nanoparticle synthesis by RAFT polymerization in CO <inf>2</inf>-induced miniemulsions

A novel environmentally friendly low-energy emulsification method that relies on pressurization with CO 2 to low pressure has been applied to reversible addition-fragmentation chain transfer (RAFT) polymerization of styrene-in-water miniemulsions with the anionic surfactant Dowfax 8390. This method circumvents traditional high-energy homogenization, and over a certain CO 2 pressure range, a transparent miniemulsion is formed. RAFT polymerization of styrene using benzyldodecyl trithiocarbonate and the aqueous phase initiator VA-044 was carried out successfully in CO 2-induced miniemulsions at 50 °C with good control/livingness. Interestingly, the particle size could be conveniently tuned via the CO 2 pressure without altering the recipe, with 6.00, 6.50, and 7.50 MPa generating number-average particle diameters of 98, 89, and 48 nm, respectively, at ∼70% conversion. The smallest particle size corresponded to the pressure range within which the emulsion was transparent. © 2012 American Chemical Society

Risk Categorization Using New American College of Cardiology/American Heart Association Guidelines for Cholesterol Management and Its Relation to Alirocumab Treatment Following Acute Coronary Syndromes

10.1161/CIRCULATIONAHA.119.042551CIRCULATION140191578-158

Effect of Alirocumab on Mortality After Acute Coronary Syndromes An Analysis of the ODYSSEY OUTCOMES Randomized Clinical Trial

10.1161/CIRCULATIONAHA.118.038840CIRCULATION1402103-11