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Chenfei Ma

Publications and source records attributed to Chenfei Ma.

3 recordsLinked to original sources

Analysis of Artemisia annua L. volatile oil by comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry.

Artemisia annua L. is an annual herb native of Asia, it has been used for many centuries for the treatment of fever and malaria. In this paper, analysis of the volatile oil of Artemisia annua L. was performed by comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC x GC-TOF MS). Three hundred and three components were tentatively identified and terpene compounds are the main components of Artemisia annua L. volatile oil. Artemisinic acid is tentatively qualified.

Artemisia annua↗

Resolution prediction and optimization of temperature programme in comprehensive two-dimensional gas chromatography.

A model is developed for predicting the resolution of interested component pair and calculating the optimum temperature programming condition in the comprehensive two-dimensional gas chromatography (GC x GC). Based on at least three isothermal runs, retention times and the peak widths at half-height on both dimensions are predicted for any kind of linear temperature-programmed run on the first dimension and isothermal runs on the second dimension. The calculation of the optimum temperature programming condition is based on the prediction of the resolution of "difficult-to-separate components" in a given mixture. The resolution of all the neighboring peaks on the first dimension is obtained by the predicted retention time and peak width on the first dimension, the resolution on the second dimension is calculated only for the adjacent components with un-enough resolution on the first dimension and eluted within a same modulation period on the second dimension. The optimum temperature programming condition is acquired when the resolutions of all components of interest by GC x GC separation meet the analytical requirement and the analysis time is the shortest. The validity of the model has been proven by using it to predict and optimize GC x GC temperature programming condition of an alkylpyridine mixture.

Chromatography, Gas↗

Enhancement of electrically evoked startle-like responses by tetanic stimulation of the superior colliculus.

Single-pulse unilateral electrical stimulation of either the amygdala or the inferior colliculus elicited startle-like responses in chloral hydrate anesthetized rats. EMG responses to intracranial stimulation were recorded from the anterior biceps femoris muscles. The EMG responses were generally enhanced following unilateral tetanic stimulation of the deep layers of the superior colliculus, but the enhancement was stronger for amygdala sites than inferior colliculus sites. The enhancement of EMG responses to ipsilateral amygdala stimulation was much larger than that for contralateral amygdala stimulation and that for ipsilateral inferior colliculus stimulation. The enhancement of EMG responses to contralateral inferior colliculus stimulation was not significant. The present study provides a motor-output model for studying plasticity in the neural pathways mediating startle facilitation.

Amygdala↗