The broad-line region and dust torus size of the Seyfert 1 galaxy PGC50427

We present the results of a three years monitoring campaigns of the $z = 0.024$ type-1 active galactic nucleus (AGN) PGC50427. Through the use of Photometric Reverberation Mapping with broad and narrow band filters, we determine the size of the broad-line emitting region by measuring the time delay between the variability of the continuum and the H$\alpha$ emission line. The H$\alpha$ emission line responds to blue continuum variations with an average rest frame lag of $19.0 \pm 1.23$ days. Using single epoch spectroscopy we determined a broad-line H$\alpha$ velocity width of 1020 km s$^{-1}$ and in combination with the rest frame lag and adoption a geometric scaling factor $f = 5.5$, we calculate a black hole mass of $M_{BH} \sim 17 \times 10^{6} M_{\odot}$. Using the flux variation gradient method, we separate the host galaxy contribution from that of the AGN to calculate the rest frame 5100\AA~ luminosity at the time of our monitoring campaign. The rest frame lag and the host-subtracted luminosity permit us to derive the position of PGC50427 in the BLR size -- AGN luminosity diagram, which is remarkably close to the theoretically expected relation of $R \propto L^{0.5}$. The simultaneous optical and NIR ($J$ and $K_{s}$) observations allow us to determine the size of the dust torus through the use of dust reverberation mapping method. We find that the hot dust emission ($\sim 1800K$) lags the optical variations with an average rest frame lag of $46.2 \pm 2.60$ days. The dust reverberation radius and the nuclear NIR luminosity permit us to derive the position of PGC50427 on the known $\tau - M{V}$ diagram. The simultaneus observations for the broad-line region and dust thermal emission demonstrate that the innermost dust torus is located outside the BLR in PGC50427, supporting the unified scheme for AGNs. (Abstract shortened, see the manuscript.)Comment: 11 pages, 23 figures, accepted for publication in Astronomy and Astrophysic

The detection and X-ray view of the changing look AGN HE 1136-2304

We report the detection of high-amplitude X-ray flaring of the AGN HE 1136-2304, which is accompanied by a strong increase in the flux of the broad Balmer lines, changing its Seyfert type from almost type 2 in 1993 down to 1.5 in 2014. HE 1136-2304 was detected by the XMM-Newton slew survey at >10 times the flux it had in the ROSAT all-sky survey, and confirmed with Swift follow-up after increasing in X-ray flux by a factor of 30. Optical spectroscopy with SALT shows that the AGN has changed from a Seyfert 1.95 to a Seyfert 1.5 galaxy, with greatly increased broad line emission and an increase in blue continuum AGN flux by a factor of > 4. The X-ray spectra from XMM-Newton and NuSTAR reveal moderate intrinsic absorption and a high energy cutoff at 100 keV. We consider several different physical scenarios for a flare, such as changes in obscuring material, tidal disruption events, and an increase in the accretion rate. We find that the most likely cause of the increased flux is an increase in the accretion rate, although it could also be due to a change in obscuration

Decaffeination of guarana seeds in a microextraction column using water-saturated CO2

Experimental data on the reduction of the caffeine content of guarana seeds with water-saturated supercritical carbon dioxide were obtained in order to provide information on the ability of supercritical fluids for the decaffeination of widely consumed caffeine-rich natural products. The extraction was performed using a semi-continuous flow high-pressure micro-extraction apparatus at 40 and 70 degreesC and pressures of 100, 200 and 400 bar. Carbon dioxide flow rates of 5.7 and 9.4 g min(-1) were used. The extraction curves obtained showed the existence of thermodynamic solubility dependent, intermediate and diffusion controlled regions. Extraction at 400 bar and 70 degreesC using water-saturated supercritical carbon dioxide at a flow rate of 5.7 g min(-1) allowed the removal of almost 98% of the initial caffeine content in wet ground guarana seeds, in a period of 240 min. When extractions were performed at lower pressures or temperatures, additional time and larger amounts of carbon dioxide were necessary to achieve the same yield. Increasing carbon dioxide flow rate did not present any economic advantage unless the extraction was limited to the thermodynamic solubility region. For total extraction of caffeine, the use of low flow rates resulted in a similar final product yield but at a much lower solvent consumption. A retrograde behavior for the extraction of caffeine from guarana seeds was also observed at 100 bar for the 40 and 70 degreesC isotherms. (C) 2002 Elsevier Science B.V. All rights reserved.22211912

Extraction of methylxanthines from guarana seeds, mate leaves, and cocoa beans using supercritical carbon dioxide and ethanol

New experimental data on the extraction of caffeine from guarana seeds and mate tea leaves, and theobromine from cocoa beans, with supercritical CO(2) were obtained using a high-pressure extraction apparatus. The effect of the addition of ethanol to carbon dioxide on the extraction efficiency was also investigated. Caffeine extraction yields of 98% of the initial caffeine content in both wet ground guarana seeds and mate tea leaves were obtained. Extractions of caffeine from guarana seeds and mate tea leaves also exhibited a retrograde behavior for the two temperatures considered in this work. In the removal of theobromine from cocoa beans, a much smaller extraction yield was obtained with longer extraction periods and consequently larger solvent requirements. The results of this study confirm the higher selectivity of CO(2) for caffeine in comparison with that for theobromine, and also the influence of other components in each particular natural product on the extraction of methylxanthines. The effect of the addition of ethanol to carbon dioxide on the extraction of methylxanthines was significant, particularly in the extraction of theobromine from cocoa beans. In general, the use of ethanol results in lower solvent and energy requirements and thereby improved extraction efficiency.50174820482

Extraction of caffeine, theobromine, and cocoa butter from Brazilian cocoa beans using supercritical CO2 and ethane

Supercritical extraction using ethane and CO2, acceptable solvents for food products, was explored for the recovery of the methylxanthines caffeine and theobromine and cocoa butter from cocoa beans using a high-pressure apparatus. Continuous extraction of cocoa beans was performed at 343.2 K using CO2 at pressures of 20 and 40 MPa and ethane at pressures of 15.2, 24.8, and 28.3 MPa. The extraction yields of cocoa butter obtained with ethane were much higher than those obtained with CO2 because of the higher solubility of this fat in ethane. A pronounced effect of pressure on the extraction of methylxanthines and cocoa butter was observed for both solvents. Extraction curves revealed the greater facility of these solvents to extract cocoa butter followed by caffeine and theobromine. This behavior suggests a range of possible conditions under which the extraction and isolation of cocoa butter, caffeine, and theobromine from cocoa beans can be achieved. The methylxanthines in cocoa beans were slightly more soluble in ethane than in CO2 probably because of co-solvency effects of cocoa butter, which was extracted more easily using supercritical ethane. Despite the higher cost of ethane, its critical pressure is lower than that of CO2, and the higher butter solubility could render ethane a viable solvent through lower energy costs.41266751675

Evaluation and modelling the utility of SCCO2 to support efficient lipase mediated esterification

Supercritical fluids offer environmental advantages over chemical solvents, while providing enhanced separation and chemical selectivity. The use of supercritical fluids for the recovery of products from biomass and the transformation of selected molecules (to add value) was studied. Free fatty acids were bio-catalytically transformed to fatty acid esters using lipase within a supercritical fluid environment. A central composite rotatable design was used to evaluate the influence of operating conditions on the enzymatic esterification process and a response surface equation was optimized to identify the most favourable process conditions for maximum free fatty acid conversion. Based on the model equation the process conditions under which it was predicted a yield of 100% esters could be obtained were: pressure 200 bar, temperature 60 °C, ethanol concentration 2.0 M, enzyme concentration 11 wt.% and time 60 min. Experiments conducted under these conditions gave an ester yield of 94.3% (close to predicted results). The activity per unit mass of biocatalyst was found to be 1585 ?mol/min/gcat. The results support the use of supercritical fluids for process integration. (Résumé d'auteur

Global yield isotherms and kinetic of artemisinin extraction from Artemisia annua L leaves using supercritical carbon dioxide

Artemisinin is an effective drug used in the malaria treatment. This drug, present in the Artemisia annua L leaves, was extracted using pressurized CO2 as solvent. The artemisinin global yields isotherms were determined at 30 and 50 degrees C with pressures in the range of 75-400 bars. The influences of temperature, pressure, and solvent flow rate on the extraction kinetics were also investigated, using a complete factorial design 2(3) (pressures of 200 and 400 bars, temperature of 30 and 50 degrees C and CO2 mass flow rate of 5.5 x 10(-5) and 11.1 x 10(-5) kg CO2/s). Extracts of A. annua L. leaves were also prepared by hydrodistillation and hexane Soxhlet. The mass transfer coefficients for constant extraction rate period were obtained from the experimental data. The extracts were analyzed by GC-FID and the artemisinin content was determined by the indirect method. The maximum artemisinin global yields were obtained at 30 degrees C and 150 bar (0.62% dry basis - d.b.) and 50 degrees C and 300 bar (0.70% d.b.). The extract obtained by hydrodistillation presented no artemisinin and the main compounds presented were camphor, P-caryophyllene, borneol e 1,8-cineol. The hexane Soxhlet artemisinin yield was 0.77% in dry basis. The experimental extraction curves were well fitted by the mathematical models of Sovova and Martinez et al., and by the empirical model. (c) 2005 Elsevier B.V. All rights reserved.361404