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71.
Ying-Han Lai Pui-Kin So Samual Chun-Lap Lo Eddy Wing Yin Ng Terence Chuen Wai Poon Zhong-Ping Yao 《Analytica chimica acta》2012
A matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS)-based method has been developed for rapid differentiation between Panax ginseng and Panax quinquefolius, two herbal medicines with similar chemical and physical properties but different therapeutic effects. This method required only a small quantity of samples, and the herbal medicines were analyzed by MALDI-MS either after a brief extraction step, or directly on the powder form or small pieces of raw samples. The acquired MALDI-MS spectra showed different patterns of ginsenosides and small chemical molecules between P. ginseng and P. quinquefolius, thus allowing unambiguous differentiation between the two Panax species based on the specific ions, intensity ratios of characteristic ions or principal component analysis. The approach could also be used to differentiate red ginseng or P. quinquefolius adulterated with P. ginseng from pure P. ginseng and pure Panax quinquefolium. The intensity ratios of characteristic ions in the MALDI-MS spectra showed high reproducibility and enabled quantitative determination of ginsenosides in the herbal samples and percentage of P. quinquefolius in the adulterated binary mixture. The method is simple, rapid, robust, and can be extended for analysis of other herbal medicines. 相似文献
72.
Poon TC Pang RT Chan KC Lee NL Chiu RW Tong YK Chim SS Ngai SM Sung JJ Lo YM 《Electrophoresis》2012,33(12):1894-1900
Previously, we reported that proteomic fingerprints were present in sera of patients with severe acute respiratory syndrome (SARS), and could separate patients into subgroups with different prognoses. In the present study, we examined the prognostic values of the SARS-associated proteomic features by biostatistical analysis, and deciphered the identities of those with prognostic values. Data of 20 SARS-associated serum proteomic features and ten serological variables from 38 SARS adult patients before treatment were subjected to multivariate logistic regression. Proteomic features of m/z 6634, m/z 7769, m/z 8635, and m/z 8865 were identified as independent prognostic markers. After purification by cation-exchange chromatography and gel electrophoresis, proteomic features of m/z 7769 and m/z 8865 were found to be platelet factor 4 (PF4) and beta-thromboglobulin (beta-TG) by tandem mass spectrometry, respectively. The associations of decreased serum PF4 and increased serum beta-TG levels with poor prognosis were confirmed by Western blot. Previous studies suggest that PF4 and beta-TG are involved in the pathogenesis of acute respiratory distress syndrome (ARDS) in a negative and positive way, respectively. Our results suggest that PF4 and beta-TG may also play similar roles in the development of ARDS in SARS patients. 相似文献
73.
74.
Y. Sun Poon 《Mathematische Annalen》1988,282(4):621-627
The author is partially supported by a grant of the National Science Foundation 相似文献
75.
Partially supported by NSF grant #DMS-9306950 and UC Riverside grant #5-510000-07427-5 相似文献
76.
Wong WY Poon SY Lee AW Shi JX Cheah KW 《Chemical communications (Cambridge, England)》2004,(21):2420-2421
Oligo(fluorenyleneethynylenegermylene)s and their polyplatinynes are synthesized and photophysically characterized; inclusion of heavy germylene bridges greatly boosts the phosphorescence decay rate in metallopolymers. 相似文献
77.
78.
We generalize the Bogomolny equations to field equations on 3
n
and describe a twistor correspondence. We consider a general hyper-Kähler metric in dimension 4n with an action of the torusT
n
compatible with the hyper-Kähler structure. We prove that such a metric can be described in terms of theT
n
-solution of the field equations coming from the twistor space of the metric. 相似文献
79.
80.