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The solubility of 1,4-naphthoquinone, plumbagin, lawsone, and juglone in supercritical carbon dioxide was determined spectroscopically at 40 degrees C, and in the pressure range 8-18 MPa. Their solubilities at 12 MPa were between 0.3 and 10 g L(-1). Plumbagin from Plumbago scandens L. roots was extracted at 40 degrees C and 20 MPa. The extracted plumbagin mass fraction was up to 0.2% in fresh roots but down to about 0.006% in aged roots. n-Hexane and chloroform extraction of such aged roots indicates that the older and dryer the roots are, the stronger they bind plumbagin. Reversed-phase HPLC indicated a relatively pure plumbagin extract with supercritical carbon dioxide.

We establish a local null controllability result for following the nonlinear parabolic equation:where b(x, r) = (r)a(x) is a function with separated variables that defines an operator which degenerates at x = 0 and has a nonlocal term. Our approach relies on an application of Liusternik's inverse mapping theorem that demands the proof of a suitable Carleman estimate.2010 Mathematics Subject Classification. Primary 35K65, 93B05; Secondary 35K55.

A specially designed high-pressure cell was used simultaneously as extractor/autoclave and photometric cell in a Perkin Elmer Lambda 5 spectrophotometer. Based on this cell, a simple method was developed to determine the extractability of pigments by pure and by modified supercritical (sc) CO2. The method is demonstrated with curcumin from turmeric. With sc CO2 modified by 10% ethanol, the extraction yield for curcumin from two commercial finely ground dry turmeric samples was about 100%, measured by reference to the (complete) extraction of samples of the same charge with pure ethanol under standard conditions. Extractable curcumin content was from 1.8 to 2.5%, with three samples of turmeric of different origins

The solubility of lapachol in supercritical CO2 was determined at 40°C and pressures between 90 and 210 bar. Supercritical fluid extraction of lapachol and some related compounds by CO2 from Tabebuia avellanedae wood is compared to Soxhlet extraction with different solvents. A standard macroscale (100-200 g wood) and a microscale (~10 mg wood) experimental setup are described and their results are compared. The latter involved direct spectrophotometric quantification in a high-pressure autoclave with an integrated optical path and a magnetic stirrer, fitted directly into a commercial spectrophotometer. The relative amount of lapachol extracted by supercritical CO2 at 40°C and 200 bar was about 1.7%, which is similar to the results of Soxhlet extractions. Lower contents of alpha- and beta-lapachone as well as dehydro-alpha-lapachone are also reported

In this paper, we are concerned with the internal control of a class of one-dimensional nonlinear parabolic systems with nonlocal and weakly degenerate diffusion coefficients. Our main theorem establishes a local null controllability result with only one internal control for a system of two equations. The proof, based on the ideias developed by Fursikov and Imanivilov, is obtained from the global null controllability of the linearized system provided by Lyusternik's Inverse Mapping Theorem. This work extends the results previously treated by the authors for just one equation. For the system, the main issue is to obtain similar results with just one internal control, which requires a new Carleman estimate with the local term just depending on one of the state function.2010 Mathematics Subject Classification. Primary 35K65, 93B05; Secondary 35K55, 93C20.

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