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71.
A highly specific recognition system, capable of distinguishing between allogeneic (non-clonemates) and syngeneic (clonemates) conspecifics, exists in Anemonia sulcata (Coelenterata: Anthozoa). During a competitive interaction between allogeneic individuals, specialized structures (acrorhagi) are exposed and used to sting opponents. This complex behavior is called the acrorhagial response. In order to quantify this behavior we measured the acrorhagial response time (period from first contact with opponent to full expansion of acrorhagi). More than 320 reciprocal histoincompatibility responses were recorded. These histoincompatibility (H) markers are free components of the sea anemone mucus: they were characterized as glyco-proteins of a molecular weight <18 KD (Kilo-Dalton) containing terminal -d-glucose and/or -d-mannose. In alloimmune memory testing experiments, the memory trace in A. sulcata was found to persist for 5 d. 相似文献
72.
Ecological surveys involving over 500 man-days between 1966 and 1969 indicate that the coral-eating sea star, Acanthaster planci, is a normal component of the coral reef community throughout the tropical Pacific, and that its abundance in the past has probably been underestimated. The sea star is not uncommon in certain environments, particularly back-reef and lagoon slopes. Sheltered, inner reefs are generally preferred over less protected reefs. Recently reported population explosions of A. planci at Guam and on the Great Barrier Reef of Australia appear to be isolated, widely-separated, local infestations of unknown cause. The infestation on the Great Barrier Reef has not spread beyond the area off Cairns and Innisfail. Approximately 40 of the more than 1000 reefs comprising the Great Barrier Reef complex have been infested heavily. 相似文献
73.
Although New Caledonia is surrounded by one of the 3 largest coral reef systems of the world, the published generic records indicate abnormally low coral diversity. Exploration of the reefs in the south-eastern part of the island, largely by means of SCUBA, has yielded specimens which increase the known genera and sub-genera by 50%. New Caledonia now ranks sixth among the coral provinces of the world, with at least 53 genera and sub-genera of reef-building corals. Many of the new records were made in a type of coral environment unlike any previously described. Comparison of the New Caledonia fauna with those of Fiji, the Grett Barrier Reef of Australia, and the Ryukyu Islands reaffirms the remarkable homogeneity of the Indo-Pacific coral faunas. 相似文献
74.
Formation of PCDF, PCDD, PCB, and PCN in de novo synthesis from PAH: mechanistic aspects and correlation to fluidized bed incinerators 总被引:6,自引:0,他引:6
The difference of polychlorinated dibenzofurans (PCDF) isomer patterns between stoker type incinerators and some fluidized bed incinerators (FBI) is a key to understand the formation mechanisms in both types of incinerators. The total yield and the isomer patterns of PCDF, polychlorinated biphenyls (PCB), polychlorinated naphthalenes (PCN), and polychlorinated benzenes (PCBz) formed via de novo synthesis from polycyclic aromatic hydrocarbons (PAH) indicate that chlorinated aromatics in the FBI are formed as a result of PAH breakdown. The detailed analysis of the isomer patterns of PCDF, PCB and PCN gives a first insight into the transformation mechanism of the PAHs and the sequence of degradation, chlorination and oxygen insertion. The major chlorination takes part at the position of the C-C cleavage during degradation of the PAHs. Further chlorination of the hydrogen position of the former PAH takes part preferably in ortho-position to this chlorination or is directed by incorporated oxygen. A perylene structure in soot is proposed as basis for the observed PCDF pattern in the FBI. Polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated phenols (PxCP) were formed in lower concentrations from the de novo experiments indicating an additional formation pathway for these compounds in the FBI. 相似文献
75.
Sorption equilibria and rates were characterized for a matrix of four aquifer sands and two slightly to moderately hydrophobic organic solutes (nitrobenzene and lindane), and the effects of sorption on the behavior of these solutes in saturated systems of the soils were determined. Experimental data were used to test and evaluate a variety of mathematical models for predicting contaminant fate and transport in groundwater systems.Observed equilibrium relationships between soil and solution phase solute concentrations were found to be described best by the nonlinear Freundlich isotherm model. It was further determined that the sorption process in the systems tested is rate controlled, requiring several days to approach equilibrium in completely mixed batch reactors. Subsequent modeling of solute transport in continuous flow soil column reactors was found to be most successful when rate-controlled models were used, the best results were obtained with a dual-resistance model incorporating the coupled mass transport steps of boundary-layer and intraparticle diffusion. 相似文献
76.
R. Michel N. Mischler B. Azambre G. Finqueneisel J. Machnikowski P. Rutkowski T. Zimny J. V. Weber 《Environmental Chemistry Letters》2006,4(4):185-189
Miscanthus × Giganteus is an excellent candidate for energy cultivation. Here we report, for the first time, the results of the pyrolysis of Miscanthus × Giganteus straw or pellets both in tubular reactor (3–6 g) and in rotary kiln (10–30 g). At 400–600°C the fractions obtained from both reactors are: solid 16–25 (wt.%); liquids 25–40; water 15–20 and gases 15–50. GC-MS analyses of pyrolysis liquids reveal the occurrence of phenolic derivatives and ethanol from lignin, furanic and linear oxygenated compounds from cellulose and hemicellulose. Finally the chars produced by the pyrolysis of M×G pellets in rotary kiln present good calorific values close to 29,000 J/g. Additionally, activated carbons with a BET surface area as high as 800–900 m2/g are produced from pellets. These results indicate that chars have a good potential either for energy production, e.g. briquetting, or as adsorbents precursors. 相似文献
77.
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79.
制备了高掺量粉煤灰为基质的聚乙烯醇/纤维素复合多孔材料。该复合材料制备过程简单易行,不需高温高压。通过XRF、XRD、FT-IR、SEM以及压汞法对该粉煤灰复合材料进行了表征和结构分析,探索了原料混合比例、干燥温度对样品结构和性能的影响。研究发现:聚乙烯醇可以有效提高该复合材料的无侧限抗压强度,纤维素可有效改善材料的孔隙结构;材料的孔隙主要来自水分蒸发过程中的气泡聚合,在外部不加压的条件下制备样品,需控制干燥温度对样品内部孔隙结构的影响。当粉煤灰含量为80%,聚乙烯醇含量为10%,纤维素含量为10%时,复合材料具有较好的孔隙率、孔隙结构、抗压强度和吸水性及保水性。有一定强度的以粉煤灰为基质的亲水性材料也适合作为吸附材料或滤料,未来可以进一步通过改善材料内部结构,以及活化功能性官能团以提高材料的综合性能,为粉煤灰的综合利用拓展途径。 相似文献
80.