Solventless Delignification of Wood Flour with TiO2/poly(ethylene oxide) Photocatalyst System

A novel solventless delignification of a defatted Picea glehnii wood flour sample was performed using a TiO₂/polyethylene oxide (PEO) photocatalyst system. A cell wall structure of the wood flour was directly observed, showing that its lignin fraction was removed by the photodegradation. The total lignin amount was slightly decreased as compared with that of the pristine sample, and the vanillin formation was confirmed by the ¹H-NMR measurement. The TiO₂ worked as a radical initiator, and simultaneously acid and aldehyde compounds produced by the PEO photolysis did as an accelerator for the solventless delignification. Although the photocatalyst system showed high delignification activity even for a low molecular lignin model, the delignification of the wood flour sample was confined to the surface. It was found that the suppressed delignification behavior was due to crosslinked structure of lignin.     

Removal of estrogenic activity of natural steroidal hormone estrone by ligninolytic enzymes from white rot fungi

Natural steroidal hormone estrone (E1) was treated with the white rot fungus Phanerochaete sordida YK-624 under ligninolytic condition with low-nitrogen and high-carbon culture medium. E1 decreased by 98% after 5 d of treatment and the activities of ligninolytic enzymes, manganese peroxidase (MnP) and laccase, were detected during treatment, which suggested that the disappearance of E1 is related to ligninolytic enzymes produced extracellularly by white rot fungus. Therefore, E1 was treated with MnP and laccase prepared from the culture of white rot fungi. HPLC analysis demonstrated that E1 disappeared completely in the reaction mixture after 1 h of treatment with either MnP or laccase. Using the yeast two-hybrid assay system, it was also confirmed that both enzymatic treatments completely removed the estrogenic activity of E1 after 2 h. These results strongly suggest that ligninolytic enzymes are effective in removing the estrogenic activity of E1.     

Effect of ammonia on the survival of Zacco platypus (Temminck and Schlegel) at each developmental stage

The survival rates were studied of fertilized eggs, larvae, fry, and adults of pale chub Zacco platypus (Temminck and Schlegel) exposed to various concentrations of ammonia. There was a decrease in hatching rate and an increase in deformed alevins at a concentration of 0.9 mg liter(-1) of ammonia. All alevins were deformed at a concentration of 1.6 mg liter(-1) of ammonia and no eggs hatched at a concentration of 3.1 mg liter(-1) of ammonia. No larvae survived for 84, 24 and 12 h at concentrations of 1.2, 2.0 and 4.7 mg liter(-1) of ammonia, respectively. Eighty percent of the fry died after 168 h and no fry survived for 24 h at concentrations of 1.6 and 2.1 mg liter(-1) of ammonia, respectively. Eighty percent of the adults died after 24 h and no adult survived for 12 h at concentrations of 1.0 and 1.9 mg liter(-1), respectively. Larger adults were the most susceptible to ammonia. The order of resistance to ammonia was eggs, fry, larvae, and adults.     

Spawning migration and returning behavior of white-streaked grouper Epinephelus ongus determined by acoustic telemetry

White-streaked grouper (Epinephelus ongus) is an important fishery target that forms fish spawning aggregations (FSAs) at specific spawning grounds. The aims of the present study were to investigate migration behavior and returning behavior in terms of FSA using acoustic telemetry. Among the 30 specimens tracked, three types of movement pattern were observed: type 1, high site fidelity at the release area before the spawning period, migration to the spawning ground during the spawning period and return to the release area just after the spawning period (17 specimens); type 2, high site fidelity at the release area, disappearance from the area during the spawning period but was not detected at the spawning ground and return to the release area (8 specimens); and type 3, high site fidelity at the release area was observed before, during and after the spawning period (5 specimens). For the 17 specimens that were categorized into type 1, the dates of departure from their release area and the dates of return to the release area of males were, respectively, significantly earlier and later than those of females. The duration between the departure date and the return date (“duration away”) of males was significantly longer than that of females. The duration away tended to be positively related to the condition factor. All 25 specimens that were categorized as type 1 and type 2 showed returning behaviors to the release area.     

Volatilization behavior of lead from molten slag under conditions simulating municipal solid waste melting

To reutilize molten slag derived from an ash melting process, the lead volatilization mechanism under reducing conditions was investigated. Reducing conditions were established by introducing a CO-CO₂-N₂ gas mixture to the reactor or by adding graphite to the molten slag prior to the experiments. As samples, two types of simulated molten slag composed of CaO-SiO₂-Al₂O₃ mixed with PbO were used and the lead volatilization behavior was studied at 1773 K. It was found that the lead volatilization rate increased on increasing the amount of reducing agent for both graphite and the CO-CO₂ gas mixture. For the CO-CO₂ reducing gas mixture, this increase was mainly attributed to PbO conversion to Pb. For the addition of graphite, the increase in lead volatilization ratio was considered to partially result from PbO conversion to Pb and partially from a reaction of graphite with SiO₂ yielding volatile SiO. The volatile SiO gas was then emitted from the furnace, which brought about a reduction in the SiO₂ content of the slag. As a result, the slag viscosity decreased, which led to an enhancement of the lead volatilization ratio.     

Reciprocal phenotypic plasticity in a predator-prey interaction between larval amphibians

In biological interactions, phenotypic change in interacting organisms induced by their interaction partners causes a substantial shift in some environmental factor of the partners, which may subsequently change their phenotype in response to that modified environmental factor. Few examples of such arms-race-like plastic responses, known as reciprocal phenotypic plasticity, have been identified in predator-prey interactions. We experimentally identified a reciprocal defensive plastic response of a prey species against a predator with a predaceous phenotype using a model system of close predator-prey interaction. Rana pirica tadpoles (the prey species) were reared with larvae of the salamander Hynobius retardatus (the predator species) having either a predaceous or a typical, nonpredaceous phenotype. The H. retardatus larvae with the predaceous phenotype, which is known to be induced by the presence of R. pirica tadpoles, induced a more defensive phenotype in the tadpoles than did larvae with the typical phenotype. The result suggests that the reciprocal phenotypic plasticity of R. pirica tadpoles is in response to a phenotype-specific signal under a close-signal recognition process.     

Simple removal of dioxins by injecting combustion gas into water

A simple, low-cost method for suppression of dioxins/furans (hereinafter referred to as dioxins) is required because many middle- and, especially, small-scale incinerators have fallen into disuse or have been dismantled because of the high running and system costs of measures for the suppression of dioxins. Therefore, the purpose of the present study was to develop a simple removal method for dioxins from combustion gas and to evaluate the basic removal rate of dioxins. The removal method for suspended matter in a gas mixture (cold model) and dioxins in exhaust gases (hot model) has been investigated by means of gas injection into water, the mechanism of which is that the suspended matter in the gas gathers at the gas–liquid interface. In the cold model, the removal ratio of fine particles (R_P) by gas injection into water was reproduced well by the following equation: R_P (%) = 100 × {1−exp(−0.8 · S_S · t_C)}, where S_S (cm²/cm³) is the specific surface area of bubbles and t_C (s) is the residence time of bubbles in water. The removal ratio of fine particles increased as the product S_s · t_C increased. In a hot model using the exhaust gas from combustion experiments of polyvinyl chloride, the removal ratio of dioxins (R_D) by injecting the exhaust gas into water was estimated by the following equation: R_D (%) = 100 × {1−exp(−0.8 · S_S · t_C · C_D0 ^0.07)}, where C_D0 [ng/cm³ (at standard temperature and pressure)] is the dioxins concentration in the exhaust gas before injection into water. R_D depends greatly on the specific surface area of bubbles and the residence time of the bubbles in water, and only weakly on the dioxins concentration in the exhaust gas. Injection of the exhaust gas into water has been shown to be effective and was evaluated as a simple method for the removal of dioxins from exhaust gas.     

滇池和洱海湖滨带水生植被状况与水质的关系研究

在滇池和洱海的湖滨带各设置了6个具有不同水生植被状况的采样点,于2010年8月-2011年5月对水温、pH、ORP、电导率、营养盐(总氮和总磷)、叶绿素a及3种DNA病毒等水质指标进行了现场或采样分析。结果表明,两湖泊中营养盐含量高的湖滨带(滇池草海和洱海沙坪湾),由于水生植物覆盖度高,湖水保持了叶绿素a含量低的状态。对洱海湖滨带的水质分析结果表明,洱海水质有较明显的季节性变化。分析表明,与水温相比,营养盐浓度可能是影响藻类生物量的更重要的因素。3种DNA病毒检测结果初步表明,水生植物不仅能控藻,而且对病毒也有抑制作用。