[Species-habitat association of a deciduous broadleaved forest in the subtropical and tempe-rate transition zone]. / 亚热带-温带气候过渡区落叶阔叶林物种-ç”Ÿå¢ƒå ³è”åˆ†æž.

The species-habitat association analysis facilitates a better understanding of species coexis-tence and community assembly. Here, all trees in a 25-hm2 broadleaved deciduous forest plot in the Qinling Mountains of North-central China were classified into three life stages (i.e., seedling, sapling, and adult). The Torus-translation test was used to examine the species-habitat association. The results showed that the association of species with habitats varied across different species. Most species were significantly associated with high slopes, 95.7% of which showed negative association. 89.5% and 90.9% of tree species were negatively associated with low slopes and ridges, respectively. Most species had positive association with high valley, with only one negative association (0.03%). There were 80, 44 and 23 significant associations with habitats at seedling, sapling and adult stages, respectively, indicating that a greater dependence of seedlings on habitat. 38 species at seedling stage and 25 species at the sapling stage were associated with at least one habitat type, while only 17 species at the adult stage were significantly associated. The effects of habitat on species varied across life stages, showing a weaker species-habitat association at the later stage. Due to the specific environmental demands, most species showed different habitat preferences across life stages.

Integrated identification, qualification and quantification strategy for pharmacokinetic profile study of Guizhi Fuling capsule in healthy volunteers.

Guizhi Fuling capsule (GZFL), a traditional Chinese medicine formulation, is widely used in China to relieve pain from dysmenorrhea and is now in a Phase II clinical trial in the USA. Due to the low exposure of the five main medicative ingredients (amygdalin, cinnamic acid, gallic acid, paeoniflorin and paeonol) of GZFL in human, a strategy was built to qualitatively and quantitatively identify the possible metabolites of GZFL and to describe the pharmacokinetic profiles of GZFL in human. In this strategy, LC-Q-TOF/MS was used to identify and structurally elucidate the possible metabolites of GZFL in vivo; and a time-based metabolite-confirming step (TBMCs) was used to confirm uncertain metabolites. The simultaneously quantitation results by LC-MS/MS showed low exposure of the five medicative ingredients. According to the strategy we built, a total of 36 metabolites were found and structurally elucidated. The simultaneously semi-quantitative analysis by LC-MS/MS showed that obvious time-concentration curves could be established for 12 of the metabolites, and most of them showed a relatively higher exposure. This study provides a better understanding of the metabolic processes of GZFL in human.

[Wet deposition of atmospheric nitrogen of the Jinshui watershed in the upper Hanjiang River].

The Jinshui River, a tributary of the Hanjiang River, is an important region of water conservation for the Middle Route of South to North Water Transfer Project. However, water quality has been deteriorated in recent years, in particular nitrogen increasing pollution. In this study, the wet deposition of atmospheric nitrogen in the Jinshui watershed was investigated between Feb. 2012-Feb. 2013, and the corresponding contribution to the river N loading was calculated using N retention model. The results indicated that the volume-weighted concentration of dissolved total nitrogen (DTN) was 0.24-2.89 mg x L(-1), consisting of ammonium (NH(4+)-N) (42.8%), nitrate (NO3- N) (13.3%) and dissolved organic nitrogen (DON) (43.9%), which decreased with rainfall volume as a result of dilution. The wet deposition of atmospheric N was mainly from anthropogenic pollution and the flux was between 4.97-7.00 kg x (hm2 x a)(-1), dominated by seasonal rainfall, of which about 81% occurred in spring and summer and the flux in a decreasing order of upstream, downstream, and middlestream. The wet deposition contributed approximately 34,000-46,000 kg N to the river, accounting for only 5.05%-6.78% of the contribution by fertilizers, which was too small to be the main source of the river N loading.

Metabolite profiles of icariin in rat plasma by ultra-fast liquid chromatography coupled to triple-quadrupole/time-of-flight mass spectrometry.

In this work, the metabolite profiles of icariin in rat plasma were qualitatively investigated, and the possible metabolic pathways of icariin were subsequently proposed. After oral administration of icariin, rat plasma samples were collected and pretreated by protein precipitation. Then these pretreated samples were injected into a Venusil ASB-C18 column with mobile phase consisted of 0.1% formic acid water and 0.1% formic acid acetonitrile and detected by Ultra fast liquid chromatography coupled to time-of-flight mass spectrometry (UFLC-TOF/MS). A total of 19 metabolites, namely, icariside I (M1), icaritin (M2), desmethylicaritin and its isomer (M3-M6), icaritin-3-O-gluA (M7), icaritin-7-O-gluA (M8), icariside II and its isomer (M9 and M10), icaritin-3,7-di-O-gluA (M11), 1,3-isoprene alcohol icaritin and its isomer (M12, M13 and M18), 1,3-isoprene alcohol icariside II (M14), allylic alcohol icaritin and its isomer (M15 and M16), 1,3-isoprene icariside II (M17) and icaritin-3-O-rha-7-O-gluA (M19) were detected and tentatively identified, and 9 of them, including M7 and M8 and M12-M18 were reported for the first time. The metabolites profiles in plasma revealed that glucuronide conjugates of isoflavonoids and flavonoid aglycones were the major circulating forms of icariin.

[HPLC fingerprint of Liuwei Dihuang condensed pills].

OBJECTIVE: To establish HPLC fingerprints of Liuwei Dihuang condensed pills. METHOD: Dikma Diamonsil C18 column (4.6 mm x 250 mm, 5 microm) was adopted, with acetonitrile (containing 0.05% phosphoric) -water (containing 0.05% phosphoric) as the mobile phase. The column temperature was set at 40 degrees C, and the flow rate was 1.0 mL x min(-1). The detection wavelength was 276 nm (0-10 min), 236 nm (10-40 min) and 276 nm (40-60 min). The sample size was 20 microL. Chromatographic peaks were identified by Q-TOF-MS-IDA-MS/MS method. RESULT: Good precision, stability and repeatability were proved. Q-TOF-MS-IDA-MS/ MS method was adopted for qualitative determination of eighteen chromatographic peaks. Ten batches of Liuwei Dihuang condensed pills were determined with the method, and their similarities were above 0. 96. CONCLUSION: The study lays a foundation for the overall quality evaluation of Liuwei Dihuang condensed pills.

[Detecting perfluorooctanoic acid by reversed phase high performance liquid chromatography with pre-column ultraviolet derivatization].

OBJECTIVES: To establish a reversed phase high performance liquid chromatographic method with pre-column ultraviolet derivatization for the determination of perfluorooctanoic acids (PFOA) in sewage and urine. METHODS: PFOA in sewage and urine formed an ion-pair with tetrabutylammonium (TBA) and were extracted into MTBE. The PFOA then reacted with omega-bromoacetophenone (omega-BAP) in acetonitrile and produced materials quantifiable by HPLC with UV detector. RESULTS: The detection limit of the proposed method was 7.0 microg/L with a relative standard deviation of less than 10%. The recoveries for real samples ranged from 85.3% to 116%. CONCLUSION: The proposed method is suitable for the determination of PFOA in sewage and urine.

[Determination of trace thallium by platform-GFAAS after preconcentration with polyurethane foam].

OBJECTIVE: To develop a method for trace thallium determination. METHODS: Thallium (L) was oxidized to thallium (III) by bromine water and the thallium (III) was complexed to [TlCl4]- in 20 mL/100 mL HCI and absorbed by polyurethane foam. The adsorbed thallium was eluted by a boiling water bath and determined by platform-GFAAS. Tl (III) could be analyzed directly and the total Tl be analyzed after oxidation, so speciation could be achieved. RESULTS: In the range of 5-100 ng/mL the linear equation was y = 0.013x + 0. 012 with the regression coefficient 0.996. The relative standard deviation was 4.7% for the standard solution of 5.00 ng/mL and the recoveries of water samples were in the range of 95.7%-104.5%. CONCLUSION: The proposed method could determine trace thallium as low as 0.02 ng/mL.

[Photodegradation of nonylphenol in water].

OBJECTIVE: To investigate the environmental degradation process of nonylphenol(NP): METHODS: The NP was detected by HPLC, and the system of ultraviolet light, ferrous ion and hydrogen peroxide was used to promote photo-degradation of NP in water. RESULTS: The maximal photo-degradation of NP occurred at the 5.0 mg/L of Fe2+, pH 2.5 and 1 ml/L of H2O2, the environmental factors in order of importance to promoting the photo-degradation of NP were: illumination time, initial concentration of NP, pH value, concentration of H2O2, concentration of Fe2+. CONCLUSION: The system of ultraviolet light, ferrous ion and hydrogen peroxide was effective in promoting the photo-degradation of NP.