Physical-Chemical Characterization and Formulation Considerations for Solid Lipid Nanoparticles

Pure glyceryl mono-oleate (GMO) (lipid) and different batches of GMO commonly used for the preparation of GMO-chitosan nanoparticles were characterized by modulated differential scanning calorimetry (MDSC), cryo-microscopy, and cryo-X-ray powder diffraction techniques. GMO-chitosan nanoparticles containing poloxamer 407 as a stabilizer in the absence and presence of polymers as crystallization inhibitors were prepared by ultrasonication. The effect of polymers (polyvinyl pyrrolidone (PVP), Eudragits, hydroxyl propyl methyl cellulose (HPMC), polyethylene glycol (PEG)), surfactants (poloxamer), and oils (mineral oil and olive oil) on the crystallization of GMO was investigated. GMO showed an exothermic peak at around ?10°C while cooling and another exothermic peak at around ?12°C while heating. It was followed by two endothermic peaks between 15 and 30 C, indicative of GMO melting. The results are corroborated by cryo-microscopy and cryo-X-ray. Significant differences in exothermic and endothermic transition were observed between different grades of GMO and pure GMO. GMO-chitosan nanoparticles resulted in a significant increase in particle size after lyophilization. MDSC confirmed that nanoparticles showed similar exothermic crystallization behavior of lipid GMO. MDSC experiments showed that PVP inhibits GMO crystallization and addition of PVP showed no significant increase in particle size of solid lipid nanoparticle (SLN) during lyophilization. The research highlights the importance of extensive physical-chemical characterization for successful formulation of SLN.     

Physical microenvironment of platelet membrane in acute myocardial infarction

Patients with acute myocardial infarction have more reactive platelets than those from normal population. These pathological platelets had more viscous plasma membrane, as inferred from fluorescence polarisation studies, and a lower fusion activation energy (delta E) of the membrane, reflecting a higher degree of order within lipid-lipid interactions.     

Introduction to the Special Section on “Optimizing Risk Management: Methods and Tools”

In recent years, risk management has attracted a great deal of attention from both researchers and practitioners. Complexity and uncertainty in many practical problems require new methods and tools. Risk management can be used as a tool for greater rewards, not just control against loss. Enterprise risk management has become an important topic in today's more complex, inter-related global business environment, replete with threats from natural, political, economic, and technical sources. Risks are studied from different silo disciplinary perspectives, with a discussion of how various methods and tools are used to optimize risk management.     

Strong stability and evolutionarily stable strategies with two types of players

Static ESS conditions are developed for the frequency evolution of a two-species haploid system by analyzing the stability of the corresponding dynamics for two pairs of strategies. A dynamic strong stability concept is introduced and shown to be equivalent to the ESS conditions in all cases where a regularity assumption is satisfied.