Huanwen Chen

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The prediction of epileptic seizures is a very important issue in the neural engineering. This is because it may improve the life quality of the patients who are suffering from uncontrolled epilepsy. In our earlier work, we found that the dynamical characteristics of EEG data with recurrence quantification analysis (RQA), also called complexity measure, can(More)
By using silver cations (Ag⁺) as the ionic reagent in reactive extractive electrospray ionization mass spectrometry (EESI-MS), the concentrations of acetonitrile in exhaled breath samples from the volunteers including active smokers, passive smokers, and non-smokers were quantitatively measured in vivo, without any sample pretreatment. A limit of detection(More)
The effect of diet on metabolites found in rat urine samples has been investigated using nuclear magnetic resonance (NMR) and a new ambient ionization mass spectrometry experiment, extractive electrospray ionization mass spectrometry (EESI-MS). Urine samples from rats with three different dietary regimens were readily distinguished using multivariate(More)
Exhaled nitric oxide (eNO) is a useful biomarker of various physiological conditions, including asthma and other pulmonary diseases. Herein a fast and sensitive analytical method has been developed for the quantitative detection of eNO based on extractive electrospray ionization mass spectrometry (EESI-MS). Exhaled NO molecules selectively reacted with(More)
There is increasing interest in using natural products as anticancer agents, as many have antioxidative properties that may help to prevent cellular damage that can lead to cancer. In addition, there is the expectation that many natural products will have low toxicity and few side effects. However, most anticancer and antioxidative agents are hydrophobic,(More)
A straight-forward analytical strategy called internal extractive electrospray ionization mass spectrometry (iEESI-MS), which combines solvent extraction of chemicals inside a bulk sample with in situ electrospray ionization mass spectrometry, has been established to directly characterize the interior of a bulk sample with molecular specificity. The method(More)
The chemical sensitivity of urine metabolomics analysis is greatly compromised due to the large amounts of inorganic salts in urine (NaCl, KCl), which are detrimental to analytical instrumentation, e.g. chromatographic columns or mass spectrometers. Traditional desalting approaches applied to urine pretreatment suffer from the chemical losses, which reduce(More)
A sensitive mass spectrometric analysis method based on the microwave plasma technique is developed for the fast detection of trace rare earth elements (REEs) in aqueous solution. The plasma was produced from a microwave plasma torch (MPT) under atmospheric pressure and was used as ambient ion source of a linear ion trap mass spectrometer (LTQ). Water(More)
Mass spectral fingerprints of 24 raw propolis samples, including 23 from China and one from the United States, were directly obtained using surface desorption atmospheric pressure chemical ionization mass spectrometry (SDAPCI-MS) without sample pretreatment. Under the optimized experimental conditions, the most abundant signals were detected in the mass(More)
Tissue spray ionization mass spectrometry (TSI-MS) directly on small tissue samples has been shown to provide highly specific molecular information. In this study, we apply this method to the analysis of 38 pairs of human lung squamous cell carcinoma tissue (cancer) and adjacent normal lung tissue (normal). The main components of pulmonary surfactants,(More)