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Summary Optically pure (+)-beta-eudesmol is a possible starting material for the synthesis of several termite defense compounds. A
two step procedure for the isolation of gram quantities of (+)-beta-eudesmol from commercially availableAmyris balsamifera oil (syn. West Indian sandalwood oil), containing 8% beta-eudesmol, was developed. Step one consisted of an efficient vacuum
distillation of the total oil. Step two was a medium pressure LC separation with an AgNO3 impregnated silica gel stationary phase. Several other separation procedures failed due to the presence of many closely related
sesquiterpene alcohols (75% of the oil). 相似文献
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Amud AE da Silva GR Tardioli PW Soares CM Moraes FF Zanin GM 《Applied biochemistry and biotechnology》2008,146(1-3):189-201
Thermoanaerobacter cyclomaltodextrin glucanotransferase (CGTase) was immobilized using different supports and immobilization methods to study
the effect on activity recovery. The enzyme covalently attached into glyoxyl-silica showed low activity recovery of 1.5%.
The hydrophobic adsorption of the enzyme on Octadecyl-Sepabeads yielded also low activity recovery, 3.83%, and the enzyme
could easily leak from the support at low ionic strength, although the immobilization yield was satisfactory, approximately
76%. The CGTase encapsulated in a sol–gel matrix gave an activity recovery of 6.94% and maximum cyclization activity at 60
°C, at pH 6.0. The half-time life at 60 °C, pH 6.0, in the presence of substrate was 100 min, which was lower than that of
the free enzyme. The best activity recovery in this work (6.94%) is approximately five times smaller than that obtained previously
using glyoxyl-agarose as support and covalent immobilization. Thus, the best support and method we tested so far for immobilization
of CGTase is covalent attachment on glyoxyl-agarose. 相似文献
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A. Sosa E. Bravin J. Harasimowicz A. Jeff C. P. Welsch The AEḡIS collaboration 《Hyperfine Interactions》2014,229(1-3):169-174
Detailed diagnostic of antiproton beams at low energies is required for essentially all experiments at the Antiproton Decelerator (AD), but will be particularly important for the future Extra Low ENergy Antiproton ring (ELENA) and its keV beam lines to the different experiments. Many monitors have been successfully developed and operated at the AD, but in particular beam profile monitoring remains a challenge. A dedicated beam instrumentation and detector test stand has recently been setup at the AE \(\bar {g}\) IS experiment (Antimatter Experiment: Gravity, Interferometry, Spectroscopy). Located behind the actual experiment, it allows for parasitic use of the antiproton beam at different energies for testing and calibration. With the aim to explore and validate different candidate technologies for future low energy beam lines, as well as the downstream antihydrogen detector in AE \(\bar {g}\) IS, measurements have been carried out using Silicon strip and pixel detectors, a purpose-built secondary emission monitor and emulsions. Here, results from measurements and characterization of the different detector types with regard to their future use at the AD complex are presented. 相似文献
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