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Nhu-Trang TT Casabianca H Grenier-Loustalot MF 《Analytical and bioanalytical chemistry》2006,386(7-8):2141-2152
Enantioselective capillary GC on a Supelco β-DEX 225 column (heptakis(2,3-di-O-acetyl-6-O-tert-butyldimethylsilyl)-β-cyclodextrin SPB 20poly—20% diphenyl, 80% dimethylsiloxane) and isotope-ratio mass spectrometry, coupled
online with capillary GC on an HP5 column have been used for origin-specific analysis and authenticity control of essential
oils, for example lemon (Citrus limon), lemongrass (Cymbopogon citratus and Cymbopogon flexuosus), citronella (Cymbopogon nardus L.—Ceylon type and Cymbopogon winterianus—Java type), Litsea cubeba, Lippia citriodora, lemon myrtle (Backhousia citriodora), lemon gum (Eucalyptus citriodora), and, especially, precious lemon balm oil (Melissa officinalis L.). Isotope data (δ13CPDB and δ2HV-SMOW) for citral (neral + geranial) and citronellal from on-line GC–C/Py–IRMS and chiral data for citronellal in these essential
oils are reported. The possibility of using these data to determine the origin of these essential oils and to detect adulteration
is discussed. Principal-components analysis (PCA) of specific compounds in two essential oils of lemongrass and Litsea cubeba was performed as a practical statistical method for distinguishing between these two types of oil. 相似文献
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We give an elementary theory of Henselian local rings and construct the Henselisation of a local ring. All our theorems have an algorithmic content. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
66.
Numerical Algorithms - We explain in this article how the famous Belgian astronomer and physicist Georges Lemaître, a specialist in the theory of relativity, rediscovered, during the Second... 相似文献
67.
We introduce a model of bargaining among groups, and characterize a family of solutions using a Consistency axiom and a few other invariance and monotonicity properties. For each solution in the family, there exists some constant α ≥ 0 such that the “bargaining power” of a group is proportional to c α , where c is the cardinality of the group. 相似文献
68.
Pascal Lefèvre Daniel Li Hervé Queffélec Luis Rodríguez-Piazza 《Mathematische Annalen》2011,351(2):305-326
We show that the maximal Nevanlinna counting function and the Carleson function of analytic self-maps of the unit disk are equivalent, up to constants. 相似文献
69.
Robert Tchitnga Hilaire Bertrand Fotsin Bonaventure Nana Patrick Hervé Louodop Fotso Paul Woafo 《Chaos, solitons, and fractals》2012,45(3):306-313
This paper shows an experimental evidence of chaos in one of the simplest imaginable autonomous implicit Hartley’s oscillator made simply of a junction field effect transistor (JFET) and a tapped coil. The experimental setup is implemented. The variations of amplitude of the oscillations through the control element are obtained showing the domain of existence of chaos. Phase portraits of the PSpice simulation, of the numerical integration and of the experiment are displayed, confirming a good agreement between theory and praxis. 相似文献
70.
María del Carmen Fernández-Ramírez Kevin Kan-Shing Ng Margarita Menéndez Douglas V. Laurents Rubén Hervás Mariano Carrión-Vázquez 《Angewandte Chemie (International ed. in English)》2023,62(19):e202209252
Understanding early amyloidogenesis is key to rationally develop therapeutic strategies. Tau protein forms well-characterized pathological deposits but its aggregation mechanism is still poorly understood. Using single-molecule force spectroscopy based on a mechanical protection strategy, we studied the conformational landscape of the monomeric tau repeat domain (tau-RD244-368). We found two sets of conformational states, whose frequency is influenced by mutations and the chemical context. While pathological mutations Δ280K and P301L and a pro-amyloidogenic milieu favored expanded conformations and destabilized local structures, an anti-amyloidogenic environment promoted a compact ensemble, including a conformer whose topology might mask two amyloidogenic segments. Our results reveal that to initiate aggregation, monomeric tau-RD244-368 decreases its polymorphism adopting expanded conformations. This could account for the distinct structures found in vitro and across tauopathies. 相似文献