Purification of Curcumin from Ternary Extract-Similar Mixtures of Curcuminoids in a Single Crystallization Step

Crystallization-based separation of curcumin from ternary mixtures of curcuminoids having compositions comparable to commercial extracts was studied experimentally. Based on solubility and supersolubility data of both, pure curcumin and curcumin in presence of the two major impurities demethoxycurcumin (DMC) and bis(demethoxy)curcumin (BDMC), seeded cooling crystallization procedures were derived using acetone, acetonitrile and 50/50 (wt/wt) mixtures of acetone/2-propanol and acetone/acetonitrile as solvents. Starting from initial curcumin contents of 67–75% in the curcuminoid mixtures single step crystallization processes provided crystalline curcumin free of BDMC at residual DMC contents of 0.6–9.9%. Curcumin at highest purity of 99.4% was obtained from a 50/50 (wt/wt) acetone/2-propanol solution in a single crystallization step. It is demonstrated that the total product yield can be significantly enhanced via addition of water, 2-propanol and acetonitrile as anti-solvents at the end of a cooling crystallization process

Real Estate Joint Venture Interests as Securities: The Implications of Williamson v. Tucker

The Fifth Circuit Court of Appeals in Williamson v. Tucker recently explicated the circumstances under which an interest in a real estate joint venture constitutes an investment contract and thus a security. The court also formulated a test for making such a determination. This Article discusses the history of investment contract analysis, critically examines the Williamson test, and suggests methods for joint venture promoters and their counsel to respond to the test

A daily diary study of stressful and positive events, alcohol use, and addiction severity among heavy drinking sexual minority men

© 2018 Elsevier B.V. Background: The purpose of this study is to examine the conditions under which daily stressful and positive events are associated with alcohol use among heavy drinking sexual minority men (SMM). Specifically, we examined the moderating effects of two indicators of alcohol addiction severity (i.e., alcohol dependence severity and negative drinking consequences) on the associations between daily stressful events and alcohol use and between daily positive events and alcohol use among heavy drinking SMM. Procedures: Secondary data analyses were performed using data from a randomized controlled trial of heavy drinking and treatment seeking SMM who were assigned male at birth (N = 200). Participants responded to a daily survey delivered via interactive voice recording (IVR). The first seven days of the IVR were analyzed for this study. Results: While accounting for treatment condition, weekday/weekend, and baseline drinking, stressful and positive events were both associated with increased daily drinking; however, indicators of alcohol addiction severity moderated these associations. For heavy drinkers with high alcohol addiction severity, daily stressful events were not associated with alcohol use, and daily positive events were associated with increased alcohol use. In contrast, for heavy drinkers with low alcohol addiction severity, daily stressful events were associated with less drinking, and daily positive events were not associated with alcohol use. Conclusions: The findings of this study indicate that alcohol addiction severity plays a key role in explaining when daily stressful or positive events are associated with daily alcohol use among heavy drinking SMM

Exact dimer ground state of the two dimensional Heisenberg spin system SrCu_2(BO_3)_2

The two dimensional Heisenberg model for SrCu_2(BO_3)_2 has the exact dimer ground state which was proven by Shastry and Sutherland almost twenty years ago. The critical value of the quantum phase transition from the dimer state to the N\'{e}el ordered state is determined. Analysis of the experimental data shows that SrCu_2(BO_3)_2 has the dimer ground state but is close to the transition point, which leads to the unusual temperature dependence of the susceptibility. Almost localized nature of the triplet excitations explains the plateaus observed in the magnetization curve.Comment: 4 pages, 5 figures, to appear in PR