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25 November 2008, Volume 2008 Issue 6 Previous Issue    Next Issue

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Impact of wind stress and Coriolis Force on the freshwater zone near Meimaosha in the Changjiang Estuary(Chinese) ZHU Jian-rong;FU Li-hui;WU Hui 2008, 2008 (6):  1-8,39.  Abstract ( 3523 )   PDF (5055KB) ( 1212 )   Save Considering multiple dynamic factors of the river discharge, tide and tidal current, topography, mixing and continental shelf current, a modified 3-D numerical ECOM model was used to study the impact of wind stress and Coriolis Force on the formation of a freshwater zone in the Meimaosha area in the South Passage of the Changjiang Estuary. There existed freshwater zone in Meimaosha area during dry season, and its formation dynamic mechanism is mainly the Changjiang runoff and tidal current oscillation. The numerical calculation results in this paper indicate that onshore Ekman transport induced by the north wind during dry season result in a wind-driven circulation, which flows toward land in the North Channel and flows toward sea in the South Channel in the bifurcation estuary. This wind-driven current prevents the saltwater intrusion from the out sea, and consequently, facilitates the formation of the freshwater zone in the South Passage. The Coriolis Force turns the water flow to the right in the northern hemisphere, and drives the upstream freshwater move downstream along the Nanhui tidal flat, which facilitates the formation of the freshwater zone in the Meimaosha area. Related Articles | Metrics

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Experimental study on vertical sediment mixingcoefficient under waves(Chinese) KONG Ya-zhen;ZHU Chuan-fang 2008, 2008 (6):  9-13.  Abstract ( 3470 )   PDF (1669KB) ( 1110 )   Save Experiments on sediment mixing characteristics under waves were carried out by using of a wave-flow-sediment flume. From experimental data, the vertical distributions of suspended sediment concentration (SSC) and vertical sediment mixing coefficients were determined under regular and irregular waves, respectively. It is found from experimental results that the vertical distribution of SSC agrees well with natural logarithm and the vertical sediment mixing coefficient may be described as εy=C1eD1Y. Related Articles | Metrics

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Numerical analysis of characteristics of temperature-salinitydistributions at the Changjiang estuary andits adjacent areas in summer(Chinese) ZHENG Xiao-qin;DING Ping-xing;HU Ke-lin 2008, 2008 (6):  14-23.  Abstract ( 4222 )   PDF (4648KB) ( 1475 )   Save Based on the Environmental Fluid Dynamic Code (EFDC), a 3-D water temperature and salinity model for the Changjiang Estuary and its adjacent areas was established. River discharge, tide, wind and solar radiation were considered in this model. Compared with the observed data in July 2005, the simulated results were fairly consistent with the observations. It can be analyzed from the results that the temperature isolines off the Changjiang Estuary in summer are along the south-north direction, with high values nearshore and low values offshore; in the Changjiang Estuary, the temperature is descending from the estuary to the offshore along the direction of Changjiang Diluted Water (CDW). The characteristics of CDW are prominent in summer. The low-salinity surface water can reach out 123° E and has a trend of east expansion off the Changjiang Estuary. The intensities of themocline and halocline are extremely high at the area of CDW, which reach the values of 0.3 ℃/m and 2/m, respectively. The positions of thermocline and halocline are coincident or close-by off the Changjiang Estuary. Related Articles | Metrics

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Magnetic properties of sediments in the middle and lower reaches of the Yangtze River ZHOU Li-min;ZHENG Xiang-min;WANG Hui;WANG Xiao-yong;HUANG Dong-feng;SONG Lian-huan;REN Shao-fang 2008, 2008 (6):  24-31.  Abstract ( 3754 )   PDF (2280KB) ( 914 )   Save The environmental magnetic properties of sediments from the middle and lower reaches of the Yangtze River were investigated for the study of environmental information of Yangtze River basin. The results show that magnetic properties of the sediments in both the mainstream and tributaries are affected by ferrimagnetic magnetite, with the magnetic domain being pseudo single domain (PSD) - multi-domain (MD). Compared with the sediments of the mainstream, the contents of imperfect anti-ferromagnetic material are higher and ferrimagnetic mineral particles are finer in those of the tributaries. With material from the tributaries into the mainstream, magnetic properties of sediments in the estuary and lower reaches of the Yangtze River change correspondingly.The contribution of the tributary sources may be the main factor controlling the regional differences of sedimentary magnetic properties in the middle and lower reaches of the Yangtze River. Related Articles | Metrics

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Study on the river piracy in Furong Gorge in ChangshanNational Geopark, Zhejiang Province(Chinese) HU Xiao-meng;WANG Du-tao;CHEN Min;LI Yi 2008, 2008 (6):  32-39.  Abstract ( 2897 )   PDF (1569KB) ( 669 )   Save Furong Gorge in Changshan National Geopark is a spectacular section with a special alluvial terrace. Based on the sediment characteristics, the landform and the datings on some sediment samples, this paper analyzed the process, the time and the reason of the river piracy which caused such phenomena. The result showed it was the Fangcun River that pirated the Furong River which originally flowed into Jinyuan River. This geomorphologic event may be the result of the movement of the faults with NE and NNW stikes in the region, which took place during 52.38~33.6 ka B.P. Related Articles | Metrics

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Patterns of urban green spaces based on linear spectral mixture model: an empirical study in Urumqi(Chinese) WANG Zhan-yong;XU Jian-hua;LÜGuang-hui;ZHANG Zhi-hua;HU Qing 2008, 2008 (6):  40-50,7.  Abstract ( 3051 )   PDF (4139KB) ( 809 )   Save The pattern of urban green spaces and its variation characteristic in Urumqi were analyzed under a linear spectral mixture model as well as vegetation landscape index, to provide a more accurate method in quantitative evaluation for ecological environment of oasis cities in arid areas. The results indicate that, (1) In terms of the region as a whole, the relevance of vegetation fraction and vegetation index is closer, but vegetation fraction is better able to reflect urban vegetation landscape with weak vegetation information at pixel scale. (2) In the past 13 years, the vegetation abundance has declined obviously overall in the study area and the serious problems of urban ecological development in Urumqi are remarkable, just like green coverage falling sharply in outskirts, greenbelt fragmentation intensifying in built-up area, spatial distribution of greenbelt being incompatible and others. (3) Viewed from vegetation types in built-up area, the vegetation with medium and high abundance has shrunk largest in area and the area of low abundance vegetation hasn’t changed much, but the fragmentation of low abundance vegetation is most serious. Moreover, the structure of urban greenbelt based on the principle of low abundance vegetation trends single obviously, which will result in instability in urban green ecosystems. Related Articles | Metrics

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Adsorption properties of humic acid and pyrene on paddy soils and its extracts(Chinese) CHEN Cheng;CHEN Hua-lin;HUANG Min-sheng 2008, 2008 (6):  51-55,1.  Abstract ( 3194 )   PDF (1094KB) ( 644 )   Save Adsorption and persistence capacity of humic acid and pyrene on two kind of paddy soils had no obvious difference. The order of adsorption and persistence capacity of humic acid was that soil > black carbon > cauterant soil. It was similar between the soil and its black carbons on the adsorption capacity of pyrene. The Freundlich equation and partition coefficients (Kf) could reflect it better. Hydrophobic or hydrophilic properties of paddy soil and its black carbons were the main factors on the adsorption proerties of humic acid and pyrene. Related Articles | Metrics

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Temporal and spatial patterns of fine root mass along a secondary succession of evergreen broad-leaved forest in Tiantong(Chinese) ZENG Fan-rong;SHI Jia-yue;YAN En-rong;ZHANG Ren-liang;WANG Xi-hua 2008, 2008 (6):  56-62.  Abstract ( 3954 )   PDF (1603KB) ( 872 )   Save This paper presented temporal and spatial patterns of fine root mass along a chronosequence of evergreen broad-leaved forest in Tiantong, Zhejiang Province of China. The level of fine root mass was highest in the forest of early successional (Lithocarpus glaber +Loropetalum chinense Comm., 3.286 t·hm-2), while lowest in that of middle successional stage(1.066 t·hm-2 and 1.531 t·hm-2).In the forest of late successional stage,the level of fine not mass was intermediate (2.715 t·hm-2 and 3.181 t·hm-2). The seasonal variation of fine root biomass(FRB) and fine root necromass(FRN) is significant (P<0.01), peaking in July and lowest in November. But in April, FRN of early successional stage forest reaches its maximum. The spatial distribution of FRB and FRN was mainly concenrated on the upper level labont 80% of the total. Fine root distribution in depth was not clearly affected by stand age. Related Articles | Metrics

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Quantitative analysis on the phytogeographic characteristics of Fagaceae dominant species in evergreen broadleaf forest(Chinese) GONG Long;YAN En-rong;WANG Xi-hua 2008, 2008 (6):  63-74.  Abstract ( 3397 )   PDF (3729KB) ( 681 )   Save Based on the distribution data of 22 dominant species of typical evergreen broadleaf forest of Castanopsis, Cyclobalanopsis and Lithocarpus (Fagaceae) and 11 climatic factors, the range types of these species and their relationship with environmental factors were analyzed by Correspond Analysis (CA) and Canonical Correspond Analysis (CCA). According to the result of CA, all could be roughly classified into two range types: east type and west type. The east type could be divided into two subtypes: south and north one. In accordance with the classification of species, the study region was also divided into three range regions: west region, northern east region and southern east region. According to the result of CCA, the major environmental factors of various spatial gradients were different. In east-west direction, the seasonality in temperature, mean temperature of the coldest month, sunshine duration, total actual solar radiation and aridity index had more effects on species distribution; while in south-north direction, the mean temperature of the coldest month and total potential solar radiation were the main limitations of the range of plants and played an important role on the northern boundary of species’ range region. Compared with other scheme of vegetation zonation of subtropical evergreen broadleaf forest zone, the boundary between eastern and western region of this paper was similar while the boundary between southern and northern region was north-leaned slightly. Related Articles | Metrics

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Effects of tributyltin on thyroid histology of Xenopus laevis(English) WANG Lei;LIU Qing-po;GUO Su-zhen;QIAN Li-juan;SHI Hua-hong 2008, 2008 (6):  75-81.  Abstract ( 3908 )   PDF (1579KB) ( 1324 )   Save Larval African clawed frogs (Xenopus laevis) were exposed to a low dose of tributyltin (25 ng•L-1TBTCl)for 2 months for thyroid histology observation. For one month after exposure, TBT could induce the depletion of colloid and vacuolation. And for two months after exposure, the incidence of follicle malformation also significantly increased, the relative transverse thyroid gland area and follicle area decreased sharply, and the number of follicle did not show any significant changes. Neither hypertrophy nor hyperplasia was observed between exposure groups and control ones. Therefore, the shrink of thyroid gland was arisen from the reduction of follicle area but not follicle number, and the depletion of colloid and follicle malformation was nothing with hypertrophy or hyperplasia. This study indicates that the low concentration of TBT can heavily damage thyroid histology of X. laevis, and TBT can be regarded as one of thyroid disrupting chemicals (TDCs). Related Articles | Metrics

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Screening identification and properties of a strain of thermophilic bacterium with strong degradation ability(Chinese) QIN Rong;LI Xiu-yan;LI Hua-zhi;HAN Bo-bo;HUANG Min-sheng 2008, 2008 (6):  82-87,1.  Abstract ( 3691 )   PDF (1114KB) ( 1035 )   Save A strain of thermophilic bacterium with strong degradation ability named YB16 was plate-screened from thermophilic compost materials. The selected strain can decompose organic macromolecules such as starch, protein, lipid and cellulose simultaneously. YB16 was aerobic, Gram positive, rod, and formed spore and capsule. The results of DNA UV absorbency showed that G+C mol% of YB16 was about 50.66%. It was considered to be a variety of Bacillus sp. YB 16 grew well at pH6.0～9.0. The optimal growth temperature was about 65 ℃. Related Articles | Metrics

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Methodological study of FTIR on planttaxonomic relationships(Chinese) CHEN Guo-qi;GUO Shui-liang;HAN Qin-xiao;WU Ping 2008, 2008 (6):  88-95.  Abstract ( 3284 )   PDF (1241KB) ( 536 )   Save In this paper, the Fourier transform infrared spectroscopy (FTIR) of the seeds of 80 herbaceous species, including subspecies and varieties of 8 families, were obtained using the method of FTIR with an OMNI collector. The peak values of FTIR between 3 100 cm-1 and 900 cm-1 were recorded and analyzed by the method of cluster analysis. The results were as follows: (1) Seeds of 80 species or subspecies could be classified into two groups. Group I included the seeds of Gramineae, Cyperaceae, Polygonaceae and Amaranthaceae, and Group II included the seeds of Compositae, Euphorbiaceae, Brassicaceae and Umbelliferae.(2) Only FTIRs of the seeds of Brassicaceae were clustered together in the dendrogram, while those of the other families all appeared farraginous.(3) Among FTIRs of the 11 groups of the congeneric species, 8 groups were clustered with other genus species, and 6 out of 7 groups of conspecific seeds appeared farraginous in the dendrogram. Therefore, the values of the application of FTIR to study the plant taxonomical relationships and to identify plant species are limited. It is suggested that the spectra of other taxa with distant taxonomical relationship should be included to evaluate the reliability of the method. Also, experimental replications should be highlighted, the significant differences between different materials should be confirmed by statistical tests in the application of FTIR to discriminate species or samples. Related Articles | Metrics

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Enchanced effect of magnesium on learning and memory ability in aged mice(Chinese) SI Wen;BAI Jing;DENG Shi-ning;ZENG Qing-wen;CAO Xiao-hua 2008, 2008 (6):  96-102.  Abstract ( 3040 )   PDF (1313KB) ( 849 )   Save The experiment was designed to investigate the effect of magnesium on learning and memory ability in aged mice. Forty aged mice (14 months old) were divided into two groups randomly, magnesium-treated group and control group. In magnesium-treated group, mice were fed with the MgCl2 solution (concentration of solution: 4 mmol/L, dose: 10 mg/kg) for 60 days and then subjected to the novel object recognition test and passive avoidance task. No significant difference was found in locomotor activity and exploration between two groups. However, in the novel object recognition test, magnesium-treated mice showed significantly higher exploratory preference to the novel object than controls. In addition, compared to the controls, magnesium-treated mice exhibited longer escape latency in the passive avoidance test, suggesting that magnesium-treated mice have better fear memory. These results indicate that magnesium can improve the ability of learning and memory in aged mice. Related Articles | Metrics

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Differentiation of different explants and enlargement of tissue culture bulb of narcissus at Chongming (Narcissus tazetta var. chinensis) (Chinese) XIONG Li-jun;LI Xiao-fang;WANG Yang;SUN Yue;XU Ling 2008, 2008 (6):  103-109.  Abstract ( 3142 )   PDF (2110KB) ( 583 )   Save This paper studied the de-differentiation and differentiation of various explants such as bulb, leaf and infancy inflorescence of narcissus (Narcissus tazetta var. chinensis). The results showed that infrastructure and infancy inflorescence of narcissus were the best explants. When the infrastructure of adventitious buds was used as explants, the quantity of buds increased three times in forty days. Additionally, it was found that KH2PO4 of certain concentration and dark conditions were favorable to enlargement adventitious buds. The anatomic structure of shoot apical meristem of bulb from field was different from that of tissue culture bulb, which might be the reason why tissue culture bulbs were very hard to enlarge. Related Articles | Metrics

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Functional analysis of gp150 and apoptosis protein in the development of Dictysotelium discoideum(Chinese) ZHANG Shu-ren;SHI Jia-le;LIU Wei;CHEN Neng-xing;HOU Lian-sheng 2008, 2008 (6):  110-115.  Abstract ( 3140 )   PDF (966KB) ( 726 )   Save Prestalk and prespore cells of Dictyostelium discoideum were separated and obtained by centrifugation of Percoll density gradients, and the expressions of gp150 and Caspase-3 in these two types of cells were analyzed by western blot. The results showed that gp150 could only be detected in prestalk cells, and the quantity of this protein increased with the development of cells. This suggested the quantity of gp150 expression had a close relationship with both of developing time and the differentiation of prestalk cells. It also showed that apoptosis proteins with the molecule weight of 31.5 kD and 37.5 kD were detected in prestalk cells and their quantities also increased with developing time. Besides, proteins of 38.2 kD could be detected in both of two types of cells. These results indicate that proteins like Caspase-3 are expressed in the progress of prestalk cell differentiation, and they are deeply correlative to the progress of apoptosis There could be a relationship between the expression of gp150 and Caspase activation. Related Articles | Metrics

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Effect of ionic strength on the particle size and gene transfection efficiency of BDCP/DNA complexes(Chinese) XIA Chun-xia;LIU Jian;WANG Yi-ting;BAO Yan-jie;WANG Xiao-xia;WANG Jing;YU Lei 2008, 2008 (6):  116-126.  Abstract ( 3778 )   PDF (1680KB) ( 693 )   Save To explore the effects of particle formation environments on gene carrier-DNA particle size and gene delivery efficiency, the particle size, binding affinity were measured of BDCP (cationic polymer, having PEI 600 backbone with biodegradable bond) in varied ionic conditions(PBS, 5% glucose, H2O). And the gene delivery efficiency and cytotoxicity were tested in similar conditions. Results showed that PBS was favorable to achieve improved stability, high gene delivery efficiency and low hemolysis effect, and BDCP/plasmid combinded in 5% glucose or H2O were found weaker binding affinity and lower transfection efficiency. Cationic carrier/DNA particle size, affinity, and gene transfection efficiency are affected by ionic strength. Related Articles | Metrics

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Empirical study of flavone from hawthorn biloba in preventing and treating insulinresistance and fatty liver in rats(Chinese) LIU Jiang;TONG Zhi;ZHANG Zai-chao;WENG Yu-jing;YE Xi-yun 2008, 2008 (6):  127-132.  Abstract ( 3065 )   PDF (2217KB) ( 902 )   Save This paper investigated the preventive effects of flavone from hawthorn biloba (FHB) in insulin resistant rats with hyperlipemia, oxidation and fatty liver, and explored the possible mechanisms on enhancing insulin sensitivity and protecting fatty liver. High-fat-sugar diet was fed in rats to produce insulin resistance model. Forty male SD rats were classified into 4 groups randomly: the normal group, the control group, the FHB group and the rosiglitazone group. Then the FHB and the rosiglitazone group were administered for 12 weeks, and blood of the rats was sampled to determin the levels of FFA, TC, TG, HDL-C and T-AOC, and the activities of AST and ALT. As a result, FHB could decrease the levels of FFA and TG, and increase the level of HDL-C, while reduce the activities of ALT, AST and liver index, and reduce the damaged degree of the liver tissue steatosis significantly. FHB also could enhance the activities of SOD and reduce the amount of MDA significantly. Meanwhile, FHB could conspicuously improve the insulin resistance and sensitivity. This work highlights the fact that FHB can regulate actions on hyperlipemia, blood glucose, insulin and oxidation, and improve liver functions of insulin resistant rats induced by high-fat-sugar diet. In addition, FHB can enhance insulin sensitivity, antagonize IR and prevent fatty liver in rats. Related Articles | Metrics

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An improved FLUTAX-EB fluorenscent labeling method for visualizing microtubule and nucleolus of ciliate(Chinese) LI Yi-song;LIU Lan-xia;SHI Lei;GU Fu-kang 2008, 2008 (6):  133-136.  Abstract ( 3133 )   PDF (2094KB) ( 560 )   Save An employment of EB in FLUTAX fluorescent labeling porcedure was proposed, with the aim of visualizing both microtubular pattern and nucleolus of three species of ciliate including Euplotes woodruffi, Oxytricha sp. and Urostyla sp.. The concentration of EB, as well as the infiltrating time was also discussed. Related Articles | Metrics