Supercritical CO2 extraction of essential oil and oleoresin from chamomile (Chamomilla recutita [L.] Rauschert)

Flowers of chamomile (Chamomilla recutita [L] Rauschert) were extracted with supercritical carbon dioxide using a fixed bed extractor. The experimental work was conducted to identify the best process conditions to maximize the yield of extract and its content of alpha -bisabolol and chamazulene. The experimental setup used a fixed bed extractor (diameter of 3.96 x 10(-2) m and length 16.55 x 10(-2) m). The fixed bed was formed with triturated chamomile ( - 28 to + 200 mesh) with an apparent density of 370 kg/m(3). Assays were conducted at temperatures of 30 and 40 degreesC, pressures of 100, 120, 160 and 200 bar. The solvent flow rates were 1.67 x 10(-5), 3.33 x 10(-5) and 6.67 x 10(-5) kg/s. A typical run took 10 h. The chemical composition of the extracts was determined using GC/MS and GC. The pressure and solvent flow rate significantly affected the mass transfer rate and the yield while the temperature did not. The maximum yield (mass of extract/mass of dried feed) was 4.33% (40 degreesC, 200 bar, 6.67 x 10(-5) kg/s). The overall extraction curves were well described by both a spline fitting and the pseudo steady state model of Sovova. The major compounds of the essential oil and of the oleoresin were beta -farnesene, alpha -farnesene, gamma -cadinene, alpha -bisabolol oxide B, alpha -bisabolol, chamazulene, alpha -bisabolol oxide A, cis and trans-dicycloether (MW 200). (C) 2001 Elsevier Science B.V. All rights reserved.21324525

Measurement of the Sigma(-) charge radius by Sigma(-)-electron elastic scattering

The Sigma (-) mean squared charge radius has been measured in the space-like Q(2) range 0.035--0.105 GeV2/c(2) by elastic scattering of a Sigma (-) beam off atomic electrons. The measurement was per-formed with the SELEX (E781) spectrometer using the Fermilab hyperon beam at a mean energy of 610 GeV/c We obtain Sigma (-) =(0.61 +/- 0.12(stat.) +/- 0.09(syst.)) fm(2). The proton and pi (-) charge radii were measured as well and are consistent with results of other experiments. Our result agrees with the recently measured strong interaction radius of the Sigma (-). (C) 2001 Elsevier Science B.V. All rights reserved

Observation of the Cabibbo-suppressed decay Xi(+)(c) -> pK(-)pi(+)

We report the first observation of the Cabibbo-suppressed charm baryon decay Xi(c)(+) --> pK(-)pi(+) We observe 150 +/- 22 +/- 5 events for the signal. The data were accumulated using the SELEX spectrometer during the 1996-1997 fixed target run at Fermilab, chiefly from a 600 GeV/c Sigma(-) beam. The branching fractions of the decay relative to the Cabibbo-favored Xi(c)(+) --> Sigma(+)K(-)pi(+) and Xi(c)(+) --> Xi(-)pi(+)pi(+) are measured to be B(Xi(c)(+) --> pK(-)pi(+))/B(Xi(c)(+) --> Sigma(+)K(-)pi(+)) = 0.22 +/- 0.06 +/- 0.03 and B(Xi(c)(+) --> pK(-)pi(+))/B(Xi(c)(+) --> Xi(-)pi(+)pi(+)) = 0.20 +/- 0.04 +/- 0.02, respectively

Charm hadroproduction results from Selex

The SELEX experiment (E781) is 5-stage magnetic spectrometer for a high statistics study of hadroproduction of charm baryons out to large x(F) using 650 Gev Sigma (-), pi (-) and p beams. The main features of the spectrometer are: a high precision silicon vertex system, powerful particle identification provided by TRD and RICH, forward Lambda (s) decay spectrometer and 3-stage lead glass photon detector. An experiment overview and spectrometer features are shown. Reconstructed charm states and results on Lambda (c), D+ particles and antiparticles produced by Sigma (-), pi (-) and p beams at x(F) > 0.3 and asymmetry for Lambda (c) are presented