共查询到20条相似文献，搜索用时 562 毫秒
1.
A new mimic biological Semi-permeable Membrane Device (SPMD) introduced for sampling organic pollutants yielded satisfactory results when it was frrst used as a passive sampler to concentrate and determine 16 kinds of polynuclear aromatic hydrocarbons (PAHs) by means of capillary GC on an HP 5890 GC-FID in coastal sediment perewater. The concentration of PAHs in sediment porewater for naphthalene(N), acenaphthlene(AL), acenaphthene (AE), fluorene (F), phenaphthene(P), anthracene(A), fluoranthene(FA), pyrene(Py), benzo[a]anthracene(B[a]A), chrysene(Chr), benzo[b] fluor- anthene(B[b]F), benzo[k]fluoranthene(B[k]F), benzo[a]pyrene(B[a]P),indeno[1,2,3,-cd]-Pyrene(I[123]P), dibenz[a,h]anthracene(D[ab]A) and benzo[g,h,i] perylene(B[ghi]P) were:50.36, under detection limits(UD), 18.19, 8.41, 8.40, 1.44, UD, 8.01, 524.15, 168.47, 50.13,123.66, 63.48, 27.40, 82.04 and 58,81 ng/L, respectively. 相似文献
2.
An improved method of PCR in which the small segment of conchocelis is amplified directly without DNA extraction was used to amplify a RUBISCO intergenic spacer DNA fragment from nine species of red algal genus Porphyra(Bangiales,Rhodophyta),including Porphyra yezoensis(Jiangsu,China),P.haitanensis(Fujian,China),P.oligospermatangia(Qingdao,China),P.katadai(Qingdao,China),P.tenera(Qingdao,China),P.suborboculata(Fujian,China),P.pseudolinearis(Kogendo,Korea),P.linearis(Devon,England),and P.fallax(Seattle,USA).... 相似文献
3.
用正交试验的方法观察影响马氏珠母贝育苗效果的七个因素：ＥＤＴＡ（Ａ）、水处理（Ｂ）、换水（Ｃ）、充气（Ｄ）、光照（Ｅ）、抗菌素（Ｆ）、倒池（Ｇ）。结果表明：影响成活率的显著因素为Ａ、Ｃ、Ｄ、Ｅ、Ｇ；影响贝苗生长的显著因素为Ｂ、Ｃ、Ｄ、Ｅ、Ｇ。加入ＥＤＴＡ、利用砂滤海水、每天换水、微弱充气、较暗的光照、使用抗菌素和定期倒池为浮游幼虫期较优的育苗方法。 相似文献
4.
Fenneropenaeus chinensis distributed in the Yellow Sea and Bohai Sea of China and the west coast of the Korean Peninsula. Different geographical populations represent potentially different genetic resources. To learn further the characteristics of different geographical population, crosses among two wild and three farmed populations were produced. The two wild populations were from the Yellow Sea and Bohai Sea (WYP), and the west coast of the Korean Peninsula and coast (WKN). The three farmed populations included the offspring of first generation of wild shrimp from coast in Korea (FKN), the Huang Hai (the Yellow Sea in Chinese) No. 1 (HH 1), and JK98. The phenotypes growth and survival rates of these populations were compared to confirm the feasibility for crossbreeding. The body length (BL), carapace length (CL), carapace width (CW), height of the second and third abdominal segment (HST), width of the second and third abdominal segment (WST), length of the first abdominal segment (LF), length of the last abdominal segment (LL), live body weight (BW), and survival rate were measured. Different combinations were statistically performed with ANOVA and Duncan's Multiple significant difference (P<0.05) in BL, CL, HST, LL, and BW; and insignificant difference (P0.05) in other growth traits and survival rate. The results of Duncan's Multiple Range Test are that BL and CL of was the best combination in all growth traits. Therefore, hybridization can introduce the variation to base populations. The systematic selection program based on additive genetic performance may be more effective than crossbreeding. 相似文献
5.
This study investigated the removal of heavy metal ions from cigarette mainstream smoke using chitosan. Chitosan of various deacetylation degrees and molecular weights were manually added to cigarette filters in different dosages. The mainstream smoke particulate matter was collected by a Cambridge filter pad, digested by a microwave digestor, and then analyzed for contents of heavy metal ions, including As(III/V), Pb(II), Cd(II), Cr(III/VI) and Ni(II), by graphite furnace atomic absorption spectrometry (GFAAS). The results showed that chitosan had a removal effect on Pb(II), Cd(II), Cr(III/VI) and Ni(II). Of these, the percent removal of Ni(II) was elevated with an increasing dosage of chitosan. Chitosan of a high deace tylation degree exhibited good binding performance toward Cd(II), Cr(III/VI) and Ni(II), though with poor efficiency for Pb(II). Except As(III/V), all the tested metal ions showed similar tendencies in the growing contents with an increasing chitosan molecular weight. Nonetheless, the percent removal of Cr(III/VI) peaked with a chitosan molecular weight of 200 kDa, followed by a dramatic decrease with an increasing chitosan molecular weight. Generally, chitosan had different removal effects on four out of five tested metal ions, and the percent removal of Cd(II), Pb(II), Cr(III/VI) and Ni(II) was approximately 55%, 45%, 50%, and 16%, respectively. In a word, chitosan used in cigarette filter can remove toxic heavy metal ions in the mainstream smoke, improve cigarette safety, and reduce the harm to smokers. 相似文献
6.
Eight known compounds were isolated from a marine-derived bacterium Streptoverticillium luteoverticillatum 11014 using bioassay-guided fractionations. Their structures were identified by spectral analysis as bis (4-hydroxybenzyl) ether (1), p-hydroxyphenylethyl alcohol (2), N-(4-hydroxyphenethyl) acetamide (3), indole-3 carboxylic acid methyl ester (4), dibenzo[b,e] [1,4]dioxine (5), thymine (6), cytosine deoxyribonucleoside (7) and 2, 3-butanediol (8). These compounds were evaluated for their cytotoxic activities against K562 cell line with the SRB method for the first time. Compounds 2 and 4 showed cytotoxcities with IC50 values of 101.1 and 165.3 μmolL-1, respectively. All compounds were isolated from S. luteoverticillatum 11014 for the first time. 相似文献
7.
《山地科学学报》2015,(2)
Four soil types(peat, marsh, meadow, and sandy) in the Zoige Plateau of China are associated with the severity of wetland degradation. The effects of wetland degradation on the structure and abundance of fungal communities and cellulase activity were assessed in these 4 soil types at 3 depths using DGGE(Denatured Gradient Gel Electrophoresis), q PCR(Quantitative Real-time PCR),and 3,5-dinitrosalicylic acid assays. Cellulase activity and abundance of the fungal community declined in parallel to the level of wetland degradation(from least to most disturbed). DGGE analysis indicated a major shift in composition of fungal communities among the4 soil types consistent with the level of degradation.Water content(WC), organic carbon(OC), total nitrogen(TN), total phosphorus(TP), available nitrogen(AN), and available phosphorus(AP) were strongly correlated with cellulase activity and the structure and abundance of the fungal community.The results indicate that soil physicochemical properties(WC, OC, TN, TP, AN, and AP), cellulase activity, and diversity and abundance of fungal communities are sensitive indicators of the relative level of wetland degradation. WC was the major factorinvolved in Zoige wetland degradation and lower WC levels contributed to declines in the abundance and diversity of the fungal community and reduction in cellulase activity. 相似文献
8.
In this paper, remote sensing techniques,as well as field studies, have been used to investigate the geomorphological processes and landscape evolution along the Saravan Fault, SE Iran to highlight how topographic features were influenced by active tectonics. Quantitative geomorphic analysis was carried out using mountain-front sinuosity(Smf),valley floor width-valley height ratio(Vf), drainage basin asymmetry factor(Af), Hypsometric integral(Hi), drainage basin shape index(Bs), mean axial slope of channel(MASC), standard deviation of topography(STD) and index of active tectonic(Iat).Remote sensing techniques, as well as field studies revealed that the Saravan Fault have three parts trending N-S, NW-SE, and E-W. Obtained results show that basins with high Iat index are located at where the strike of the Saravan Faults changes and where several strike-slip faults are crossed the Saravan fault. 相似文献
9.
为研究生物酶采油解堵剂中产蛋白酶菌株的初、复筛选及培养条件优化,从大庆原油样品中筛选菌种,通过水解酪素的透明圈实验及福林酚测蛋白酶酶活的方法进行菌株的初、复筛选;以蛋白酶酶活为优化指标,采用单因素实验对筛选的产蛋白酶菌株的培养基及培养条件进行优化,优化最适培养基:可溶性淀粉为15g/L,蛋白胨为20g/L,酵母膏为20g/L,NaCl为1.0g/L,CaCl2为0.02g/L,Na2HPO4为0.2g/L,NaH2PO4为0.1g/L;在初始pH为6.0、接种量为5%(体积分数)、温度为31℃、摇床转速为160r/min的条件下,培养72h后,菌株的蛋白酶酶活为551.0U/mL,为复筛选菌株的蛋白酶酶活的22.92倍,即为菌株生长繁殖及代谢的最佳条件,能够获得更高的蛋白酶酶活,有利于后续实验的进行.结果表明:菌株产蛋白酶对原油作用效果为发酵液表面张力从作用前的56.2mN/m降低到作用后的30.5mN/m,表面张力显著降低,还有降解降黏原油等效果,具有一定的研究价值. 相似文献
10.
Cloning and sequencing of the genes coding for the α- and β- subunit of phycoerythrin (PE) of a red alga—Gracilaria lemaneiformis (GL) are reported. Alignment of 1084 nucleotides sequenced with three known red algal PE genes,Rhodella violacea (RV),Polysiphonia boldii (PB) andAglaothamnion neglectum (AN), showed high level of conservation, and similarities of 77,6% (between GL and RV), 77.9% (GL and AN) and 79.0% (GL and
PB). The similarities of amino acids were 84.8% (between GL and RV), 85.7% (GL and PB), and 80.6% (AN and GL), higher than
those among nucleotides.
Project 39670405 supported by NSFC and Japanese Science Promotion Society (JSPS). 相似文献
11.
Drought Forecasting in a Semi-arid Watershed Using Climate Signals:a Neuro-fuzzy Modeling Approach 总被引：6，自引：3，他引：3
Bahram CHOUBIN Shahram KHALIGHI-SIGAROODI Arash MALEKIAN Sajjad AHMAD Pedram ATTAROD 《山地科学学报》2014,(6):1593-1605
Large-scale annual climate indices were used to forecast annual drought conditions in the Maharlu-Bakhtegan watershed,located in Iran,using a neuro-fuzzy model.The Standardized Precipitation Index（SPI） was used as a proxy for drought conditions.Among the 45 climate indices considered,eight identified as most relevant were the Atlantic Multidecadal Oscillation（AMO）,Atlantic Meridional Mode（AMM）,the Bivariate ENSO Time series（BEST）,the East Central Tropical Pacific Surface Temperature（NINO 3.4）,the Central Tropical Pacific Surface Temperature（NINO 4）,the North Tropical Atlantic Index（NTA）,the Southern Oscillation Index（SOI）,and the Tropical Northern Atlantic Index（TNA）.These indices accounted for 81% of the variance in the Principal Components Analysis（PCA） method.The Atlantic surface temperature（SST：Atlantic） had an inverse relationship with SPI,and the AMM index had the highest correlation.Drought forecasts of neuro-fuzzy model demonstrate better prediction at a two-year lag compared to a stepwise regression model. 相似文献
12.
Eight compounds were isolated from red alga Gymnogongrus flabelliformis Harv. In normal phase silica gel, Sephadex LH-20 gel column chromatography, reverse phase HPLC, and recrystallization. Based on MS and ID NMR spectroscopic data, their structures were determined as： stigmast-4-en-3-one （Ⅰ）, cholest-4-en-3-one （Ⅱ）, cholesterol （m）, uracil （Ⅳ）, uridine （V）, adenosine （Ⅵ）, succinic acid （Ⅶ）, and 5-hydroxy-4-methyl-5-pentyl-2,5-dihydro-furan-2-on （Ⅷ）. All of them were obtained from this species for the first time. Cytotoxicity of these compounds was screened using standard MTT method, but all the compounds were inactive （IC50 〉 10 μg/ml）. 相似文献
13.
高州水库(1988)发现的44种轮虫中有8种为优势种。它们是螺形龟甲轮虫、针簇多肢轮虫、圆筒异尾轮虫、奇异巨腕轮虫、裂痕龟纹轮虫、卡顿圆筒异尾轮虫、卵形彩胃轮虫和真翅多肢轮虫。它们中除奇异巨腕轮虫、裂痕龟纹轮虫和真翅多肢轮虫外,其余的种类全年出现。8种的种群密度为46.1个/升。它们的个体数量占轮虫总量的83.8%。一年中以夏、秋密度最高,分别占41.2%和39.6%,而春、冬密度最低,各为10.7%和8.5%。文中还讨论了这八种轮虫各种高峰形成的量适温幅以及它们的分布与水质的关系。 相似文献
14.
【目的】探明花鲈(Lateolabrax maculatus)早期主要形态性状对体质量的影响程度,为其良种选育提供参考。【方法】采用数理统计方法对500尾2月龄花鲈的全长(X1)、体长(X2)、体高(X3)、头长(X4)、头高(X5)、躯干长(X6)、吻长(X7)、眼径(X8)、尾柄长(X9)、尾柄高(X10)等10个形态性状和体质量(Y)进行测量分析。【结果】相关性分析结果表明,10个形态性状与体质量的相关性均达到了极显著水平(P<0.01)。通径分析结果发现,体高、全长、眼径、躯干长、吻长、体长等6个性状是影响2月龄花鲈体质量的主要形态性状,其中仅体高对体质量的直接作用大于间接作用,为影响体质量的核心变量。决定系数显示,体高对体质量的单独决定系数最大(0.324),全长和体高对体质量的共同决定系数最大(0.287),6个形态性状对体质量的总决定系数为0.947,表明本研究已将影响2月龄花鲈体质量的主要形态性状全部纳入。经逐步回归分析,拟合得到最优线性回归方程为Y=-1.468+1.314X3+0.160X1-0.307X8+0.149X6+0.305X7+0.046X2。【结论】除体质量外,还须将体高作为花鲈早期选育的目标性状。 相似文献
15.
Excessive alcohol consumption leads to liver disease. Extensive evidence suggests that C-phycocyanin (C-PC), a chromophore phycocyanobilin derived from Spirulina platensis, exerts protective effects against chemical-induced organ damage. In this study, we investigated whether C-PC could protect against ethanol-induced acute liver injury. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglyceride (TG), total cholesterol (CHOL), low-density lipoprotein (LDL), liver homogenate malondialdehyde (MDA), superoxide dismutase (SOD) content were measured, and pathological examination of liver sections were examined. C-PC showed obvious inhibitory effects on serum ALT, AST, TG, CHOL, LDL and MDA, and SOD content significantly increased in the liver. The structure of hepatic lobules was clear, liver sinus returned to normal, and liver cell cords were arranged in neat rows. Cloudiness, swelling, inflammatory cell infiltration and spotty necrosis of liver cells were significantly reduced. Therefore, C-PC can significantly protect against ethanol-induced acute liver injury. 相似文献
16.
《中国地理科学(英文版)》2020,(2)
Urban particulate matter 2.5(PM_(2.5)) pollution and public health are closely related, and concerns regarding PM_(2.5) are widespread. Of the underlying factors, the urban morphology is the most manageable. Therefore, investigations of the impact of urban three-dimensional(3D) morphology on PM_(2.5) concentration have important scientific significance. In this paper, 39 PM_(2.5) monitoring sites of Beijing in China were selected with PM_(2.5) automatic monitoring data that were collected in 2013. This data set was used to analyze the impacts of the meteorological condition and public transportation on PM_(2.5) concentrations. Based on the elimination of the meteorological conditions and public transportation factors, the relationships between urban 3D morphology and PM_(2.5) concentrations are highlighted. Ten urban 3D morphology indices were established to explore the spatial-temporal correlations between the indices and PM_(2.5) concentrations and analyze the impact of urban 3D morphology on the PM_(2.5) concentrations. Results demonstrated that road length density(RLD), road area density(RAD), construction area density(CAD), construction height density(CHD), construction volume density(CVD), construction otherness(CO), and vegetation area density(VAD) have positive impacts on the PM_(2.5) concentrations, whereas water area density(WAD), water fragmentation(WF), and vegetation fragmentation(VF)(except for the 500 m buffer) have negative impacts on the PM_(2.5) concentrations. Moreover, the correlations between the morphology indices and PM_(2.5) concentrations varied with the buffer scale. The findings could lay a foundation for the high-precision spatial-temporal modelling of PM_(2.5) concentrations and the scientific planning of urban 3D spaces by authorities responsible for controlling PM_(2.5) concentrations. 相似文献
17.
The performance of six statistical approaches,which can be used for selection of the best model to describe the growth of individual fish,was analyzed using simulated and real length-at-age data.The six approaches include coefficient of determination(R2),adjusted coefficient of determination(adj.-R2),root mean squared error(RMSE),Akaike's information criterion(AIC),bias correction of AIC(AICc) and Bayesian information criterion(BIC).The simulation data were generated by five growth models with different num... 相似文献
18.
《中国海洋湖沼学报》2017,(1)
Coral bleaching has generally been recognized as the main reason for tropical coral reef degradation, but there are few long-term records of coral bleaching events. In this study, trace metals including chromium(Cr), copper(Cu), molybdenum(Mo), manganese(Mn), lead(Pb), tin(Sn), titanium(Ti), vanadium(V), and yttrium(Y), were analyzed in two Porites corals collected from Meiji Reef in the tropical South China Sea(SCS) to assess differences in trace metal concentrations in bleached compared with unbleached coral growth bands. Ti, V, Cr, and Mo generally showed irregular fluctuations in both corals. Bleached layers contained high concentrations of Mn, Cu, Sn, and Pb. Unbleached layers showed moderately high concentrations of Mn and Cu only. The different distribution of trace metals in Porites may be attributable to different selectivity on the basis of vital utility or toxicity. Ti, V, Cr, and Mo are discriminated against by both coral polyps and zooxanthellae, but Mn, Cu, Sn, and Pb are accumulated by zooxanthellae and only Mn and Cu are accumulated by polyps as essential elements. The marked increase in Cu, Mn, Pb, and Sn are associated with bleaching processes, including mucus secretion, tissue retraction, and zooxanthellae expulsion and occlusion. Variation in these trace elements within the coral skeleton can be used as potential tracers of short-lived bleaching events. 相似文献
19.
In this study, specific growth rate (SGR), ingestion rate (IR), food conversion ratio (FCR), apparent digestion ratio (ADR) and ammonium-nitrogen excretion were determined for sea cucumber (Stichopus m... 相似文献
20.
R. G. Monsalud F. O. Magbanua M. P. Parungao C. G. B. Banaay M. H. D. Bayer J. K. Yap L. M. Tapay 《中国海洋大学学报(英文版)》2002,1(1):101-104
The prime function of the Philippine National Collection of Microorganisms (PNCM), being the national repository of microbial
strains, is to collect and preserve strains for their continued viability and availability for future use. To date, a total
of 2144 strains of bacteria (1357), yeasts (250), filamentous, fungi (377), algae (14), and strains still to be identified
(146) are maintained at the PNCM. These are preserved and maintained using various methods which include modified liquid drying
(lyophilization), ultra-low temperature (−70°C) storage in 10% glycerol, storage in sterile soil, distilled water and overlaying
with mineral oil. Periodic viability testing is done to assess the stability of these preserved cultures under storage. Aside
from preservation and maintenance of cultures, the PNCM is also involved in several research activities. One of these is the
isolation, characterization and identification of some Vibrio isolates from the Philippines. Details on this particular study
is presented in this report. 相似文献