Optimization of the microwave-assisted extraction of phlorotannins from Saccharina japonica Aresch and evaluation of the inhibitory effects of phlorotannin-containing extracts on HepG2 cancer cells

The use of a microwave-assisted extraction(MAE) method for the extraction of phlorotannins from Saccharina japonica Aresch(S.japonica) has been evaluated with particular emphasis on the influential parameters,including the ethanol concentration,solid/liquid ratio,extraction time,extraction temperature,and microwave power.The MAE procedure was optimized using single-factor design and orthogonal array design(OAD).The content of total phlorotannins in S.japonica was determined using a Folin-Ciocalteu(FC) assay.A maximum total phlorotannin content of 0.644 mg of phloroglucinol equivalent per gram of dry weight plant(mg PGE/g DW) was obtained using the optimized model,which included an ethanol concentration of 55%,solid/liquid ratio of 1:8,extraction time of 25 min,irradiation power of 400 W,and temperature of 60°C.Under similar conditions,the application of a conventional extraction method led to a lower phlorotannin yield of 0.585 mg PGE/g WD.These results demonstrated that the MAE approach provided better results for the extraction of phlorotannins from S.japonica and was a promising technique for the extraction of phenolic compounds from S.japonica and other materials.In addition,screening tests for the inhibitory activity showed that the phlorotannin-containing extracts significantly inhibited the growth of human hepatocellular carcinoma cells(HepG2) by inducing their apoptosis.The morphological changes that occurred during cell apoptosis were characterized using Hoechst33258 staining.     

大兴安岭中南段昌图锡力锰、银、铅、锌多金属矿床的发现及其意义

中国地质调查局天津地质调查中心与黑龙江省地质调查研究总院齐齐哈尔分院合作,在内蒙古霍林郭勒地区发现昌图锡力锰、银、铅、锌多金属矿床。矿床所在大地构造位置为中亚造山带东段,矿床产于中生代白音高老组中发育的北西向破碎蚀变带中。经地表槽探揭露可见7条矿脉沿北西向平行展布。矿体及围岩中仅发现低温蚀变,主要包括硅化、绢云母化、绿泥石化、褐铁矿化及碳酸盐化。根据蚀变矿物类型及矿体强烈受北西向构造控制等特征,初步判断矿床可能为浅成低温热液矿床。在大兴安岭中南段首次发现锰多金属热液矿床,暗示在太平洋构造域控制下,大兴安岭中南段北东向成矿带内部可能存在受北西向构造控制的次级成矿带。     

Mantle anisotropy across the southwestern boundary of the Ordos block,North China

Located at the northeastern margin of the Tibetan plateau,the Ordos block is a stable tectonic unit in North China.With its active boundary fault zones,the Ordos block played an important role in the eastward extrusion mechanism of the Tibetan plateau.Peking University deployed a linear array of 15 portable broadband seismometers across the western Weihe graben during September 2005 to August 2006 and later a 2-D seismic array(Southwest Ordos Array) of 14 portable broadband seismometers during 2007-2008 at its southwestern boundary.Analyses of shear wave splitting of SKS and SKKS phases at these stations show that the fast directions trend ～110° with an average delay time of 0.9 s in the southwestern margin of the Ordos block.The agreement between the lithosphere deformation indicated by GPS data and Quaternary fault slip-rate observations and the mantle flow represented by shear wave splitting implies that accordant deformation patterns from lithosphere to asthenosphere in relation to the eastward extrusion of the Tibetan plateau could extend at least to 200 km depth.Spatial distribution of splitting polarization directions indicates that the mantle flow driven by the Tibetan plateau is blocked by the Ordos block and locally restricted in a narrow channel along the Qinling-Dabie fault zones between the Ordos block and Sichuan basin.     

西宁市CORS中坐标转换方法的研究

讨论了西宁市CORS中的坐标转换方法,研究了坐标转换方法,实现了三维空间基准到二维平面基准的高精度转换。     

地理标志农产品和农业经济的时空演变及交互响应

利用多指标综合评价法、协调发展度模型、灰色关联度模型和P-VAR模型对中国326个地级以上行政单元的地理标志农产品与农业经济的时空演化、协同发展、交互响应关系进行了综合测度。研究表明：① 地理标志农产品和农业经济发展水平均具有整体上升态势,在空间上分别呈“大分散、小集聚”和“阶梯式下降”的分布特征。② 地理标志农产品和农业经济的协调发展等级由初级协调演化为高级协调,空间差异先增大后减小;二者间具有显著的、持续强化的关联性。③ 地理标志农产品和农业经济均具有正向的自我强化与惯性增长特征,地理标志农产品对农业经济的影响程度较小,而农业经济对地理标志农产品的影响程度较大,形成倒逼作用。     

Effects of nitrogen and sulphide on macroinfaunal community: a microcosm study

A microcosm experiment was conducted to test the short-term effects of nitrogen (as TKN, total Kjeldahl nitrogen) and sulphide (as AVS, acid volatile sulphide) on macrobenthic infauna over a period of 8 weeks. The experiment consisted of four treatments using sediment cores (D: 8 cm, H: 20 cm) with addition of: I, nitrogen (N) to an in situ mean level of 0.48 mg Ng(-1) dw; II, sulphidic solution (S) to an in situ mean level of 318.8 microM S g(-1) dw; III, nitrogen and sulphidic solution (NS) to in situ mean levels of 0.45 mg Ng(-1) dw and 329.0 microM S g(-1) dw, respectively, and IV, control with no addition of N and S. Sediment cores were retrieved for analysis of infaunal composition after weeks 2, 4 and 8. A total of 646 specimens of macrobenthic infauna belonging to 27 species were recorded from the cores, in which polychaetes were the most abundant with respect to species and individual numbers. Mean species number and diversity H' of the control and N treatment was statistically higher than S and NS treatments, mean individual number of the S treatment was larger than the NS treatment, and mean evenness J of the S treatment was lower than the N and NS treatments as well as the control. Individual numbers also showed a significant increase from weeks 2 to 8, whereas evenness J decreased in weeks 4 and 8. Multivariate analyses of the faunal data suggested that benthic composition of the N treatment and control did not differ during the experimental period, but changes in benthic structure in S and NS treatments were evident. The present findings demonstrated the dose-response relationship of benthic species changes under controlled addition of N and S. The response to N and S additions in the sediment microcosms was in agreement with the general effects of organic enrichment on macrobenthic communities along a spatial gradient of organic pollution as described by Pearson and Rosenberg [Pearson, T.H., Rosenberg, R., 1978. Macrobenthic succession in relation to organic enrichment and pollution of the marine environment. Oceanography and Marine Biology Annual Review 16, 229-311]. However, in the present experiment, community changes in the treatments were observable in a short, temporal scale.