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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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Potential‐Assisted DNA Immobilization as a Prerequisite for Fast and Controlled Formation of DNA Monolayers 下载免费PDF全文
Daliborka Jambrec Dr. Magdalena Gebala Dr. Fabio La Mantia Prof. Dr. Wolfgang Schuhmann 《Angewandte Chemie (International ed. in English)》2015,54(50):15064-15068
Highly reproducible and fast potential‐assisted immobilization of single‐stranded (ss)DNA on gold surfaces is achieved by applying a pulse‐type potential modulation. The desired DNA coverage can be obtained in a highly reproducible way within minutes. Understanding the underlying processes occurring during potential‐assisted ssDNA immobilization is crucial. We propose a model that considers the role of ions surrounding the DNA strands, the distance dependence of the applied potentials within the electrolyte solution, and most importantly the shift of the potential of zero charge during the immobilization due to the surface modification with DNA. The control of the surface coverage of ssDNA as well as the achieved speed and high reproducibility are seen as prerequisites for improved DNA‐based bioassays. 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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Intercalation of Proflavine in ssDNA Aptamers: Effect on Binding of the Specific Target Chloramphenicol 下载免费PDF全文
The structural modification of ssDNA‐based aptamers upon specific binding of its target molecule leads to changes of the charge‐transfer resistance (Rct) of a negatively‐charged free‐diffusing redox probe. The aptamer adopts a structure due to self‐hybridization which is stabilized using profalvine as intercalator. The pre‐organized aptamer structure is used to detect chloramphenicol (CAP) requiring a substantial change of the aptamer structure indicated by a CAP concentration dependent increase in the Rct values. Pre‐incubation of the aptamer‐modified electrode with an intercalator allows for the modulation of the aptamer/target interaction and hence for a modulation of the CAP‐dependent variation of the Rct values. 相似文献