The structural characterization of glycosaminoglycans (GAG) oligosaccharides has been a long-standing challenge in the field of mass spectrometry. In this work, we present the application of electron detachment dissociation (EDD) Fourier transform mass spectrometry to the analysis of dermatan sulfate (DS) oligosaccharides up to 10 residues long. The EDD mass spectra of DS oligosaccharides were ...

Four new dammarane-type triterpene saponins named floranotoginsenosides A (1), B (2), C (3) and D (4), together with five known triterpene saponins, were isolated from the flowers of Panax notoginseng. Their structures were elucidated on the basis of spectral and chemical evidence.

We investigate the dynamics and spatial distribution of land use fragmentation in a rapidly urbanizing region of the United States to test key propositions regarding the evolution of sprawl. Using selected pattern metrics and data from 1973 and 2000 for the state of Maryland, we find significant increases in developed and undeveloped land fragmentation but substantial spatial heterogeneity as w...

This paper is concerned with extracting and summarizing the spatial pattern that may be present in landcover and other thematic raster maps. A sequence of rather large frequency tables is calculated by scanning the map and recording the landcover in configurations of four pixels whose inter-pixel distances become increasingly large. Perceived spatial pattern in a map is determined in part by do...

Forest fragmentation occurs when a contiguous patch of forest is transformed into disjunct patches. This reduces the quality of habitat for bird species of ecological and recreational importance, and is considered to be a primary cause of declines in the populations of many migratory songbirds. In this paper, we analyze the effects of market-based policies on forest fragmentation in the coastal...

The flavonoids and xanthones present in the ethanol extracts of leaves stems Fridericia samydoides showed that anti-dengue activities vitro were investigated qualitatively by liquid chromatography-ultraviolet-mass spectrometry series. Nineteen flavones fifteen detected characterized on basis their fragmentation pattern positive negative ion mode tandem mass spectra ultraviolet bands. Acacetin, ...

The 70 ev positive and negative ion mass spectra of ring-substituted nitrobenzenes were studied. The influence of the substituent group on the fragmentation modes of the molecular ions is discussed. The effect of pressure in the formation of negative ions was also studied. As expected, the ratio of fragment ions to negative molecular ions decreased with increasing pressure in ion source.