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The paper presents a modified and universally applicable diagnostic fragment-ion-based extension strategy (DFIBES) to efficiently process the information acquired by liquid chromatography-electrospray ionization source in combination with hybrid ion trap and high-resolution time-of-flight mass spectrometry [LC-(ESI)-IT-TOF/MS], facilitating the structural determination of serial components contained in traditional Chinese medicine prescription (TCMP). The key advantage of DFIBES is that it facilitates the rapid classification of the complicated peaks into well-known chemical families, which significantly simplifies the complicated procedures of structural characterization. Moreover, considering that a certain family of compounds usually produces identical fragment ions, the DFIBES would be widely applicable to many other families of compounds identification besides the presently validated ginsenosides and lignans. Shengmai injection, composed of Panax ginseng, Radix ophiopogonis, and Schisandra chinensis, was taken as a TCMP example to conduct and validate the proposed DFIBES. Diagnostic fragment ions (DFI) for each chemical family contained in Shengmai injection was firstly determined or proposed from the separated analysis of 15 authentic standards and the extract of S. chinensis. The ESI-MSn fragmentation patterns of ginsenosides and lignans were then systematically studied for developing the 'structure extension' approach. Upon LC-IT-TOF/MS analysis and DFIBES, more than 30 ginsenosides and 20 lignans have been rapidly detected and identified from Shengmai injection, supporting that the DFIBES is a very powerful strategy and would be widely applicable for the complicated components identification from TCMP and other complicated mixtures.

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We estimate Antarctic ice-flow balance velocities, which are the average speeds that ice must flow downslope through a volume assuming that there are equal amounts of ice entering and leaving the ice volume. We use the OSU (Ohio State University) digital elevation model of Antarctica, recent ice accumulation rate data and the BEDMAP ice-thickness data compilations for Antarctica to characterize the physical properties of the ice sheet that are included in the balance-velocity calculation. We adapt a flux algorithm from the hydrology literature that enables us to calculate the flux distribution from any cell in any order. Flux from one cell to its neighbors is partitioned as a simple function of surface slope direction. Digitized flow-stripe directions from satellite images minimize errors in flow direction where surface slopes are low or complex. We estimate errors in balance velocity arising from errors in the data and show semi-quantitatively how properties of the algorithm bias the balance-velocity result. We find a favorable comparison between our model and observed velocity data as well as the balance-velocity patterns reported by other researchers.

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