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11.
The first method for quantifying cannabinoids and cannabinoid glucuronides in whole blood by liquid chromatography–tandem
mass spectrometry (LC–MS/MS) was developed and validated. Solid-phase extraction followed protein precipitation with acetonitrile.
High-performance liquid chromatography separation was achieved in 16 min via gradient elution. Electrospray ionization was
utilized for cannabinoid detection; both positive (Δ9-tetrahydrocannabinol [THC] and cannabinol [CBN]) and negative (11-hydroxy-THC [11-OH-THC], 11-nor-9-carboxy-THC [THCCOOH],
cannabidiol [CBD], THC-glucuronide, and THCCOOH-glucuronide) polarity were employed with multiple reaction monitoring. Calibration
by linear regression analysis utilized deuterium-labeled internal standards and a 1/x
2 weighting factor, yielding R
2 values >0.997 for all analytes. Linearity ranged from 0.5 to 50 μg/L (THC-glucuronide), 1.0–100 μg/L (THC, 11-OH-THC, THCCOOH,
CBD, and CBN), and 5.0–250 μg/L (THCCOOH-glucuronide). Imprecision was <10.5% CV, recovery was >50.5%, and bias within ±13.1%
of target for all analytes at three concentrations across the linear range. No carryover and endogenous or exogenous interferences
were observed. This new analytical method should be useful for quantifying cannabinoids in whole blood and further investigating
cannabinoid glucuronides as markers of recent cannabis intake. 相似文献
12.
Bernard?SonnenscheinEmail author Thomas K. DM.?Peron Francisco A.?Rodrigues Jürgen?Kurths Lutz?Schimansky-Geier 《The European Physical Journal B - Condensed Matter and Complex Systems》2014,87(8):182
We study the collective dynamics of noise-driven excitable elements, so-called active rotators. Crucially here, the natural frequencies and the individual coupling strengths are drawn from some joint probability distribution. Combining a mean-field treatment with a Gaussian approximation allows us to find examples where the infinite-dimensional system is reduced to a few ordinary differential equations. Our focus lies in the cooperative behavior in a population consisting of two parts, where one is composed of excitable elements, while the other one contains only self-oscillatory units. Surprisingly, excitable behavior in the whole system sets in only if the excitable elements have a smaller coupling strength than the self-oscillating units. In this way positive local correlations between natural frequencies and couplings shape the global behavior of mixed populations of excitable and oscillatory elements. 相似文献