Comparative sensitivity of various developmental stages of sea urchins to some chemicals

The sensitivity to some chemical agents was examined comparatively at sperm, fertilization, cleavage, blastula, gastrula, pluteus and metamorphosis stages of a sand dollar from Japanese waters (Peronella japonica) and a sea urchin from the Pacific coast of Australia (Heliocidaris erythrogramma). These agents included Cu sulphate, ABS and NH₃ chloride. Responses observed included departures from control rates of fertilization and developmental reduction at the attainment of first cleavage, gastrula, pluteus or metamorphosis. Developmental anomalies were noted at the fertilization, 2-cell, gastrula, pluteus and metamorphosis stages. Using minimum effective concentrations of the 3 chemicals at various developmental stages of P. japonica, it was found that sensitivity to chemicals varies from fertilization to metamorphosis. It seems that sperm activity is the most sensitive, and that fertilization and gastrulation are more sensitive than first cleavage, blastulation and pluteus formation. H. erythrogramma seems to show nearly the same responses to Cu, but is more sensitive at metamorphosis.Experiments conducted at the Seto Marine Biological Laboratory, Wakayama Prefecture, JapanExperiments conducted at School of Biological Sciences, the University of Sydney, Sydney, N.S.W., AustraliaContributions from the Seto Marine Biological Laboratory, No. 664     

A game model for dominance relations among group-living animals

We present here an attempt to understand behaviors of dominant individuals and of subordinate individuals as behavior strategies in an asymmetric “hawk-dove” game. We assume that contestants have perfect information about relative fighting ability and the value of the resource. Any type of asymmetry, both relevant to and irrelevant to the fighting ability, can be considered. It is concluded that evolutionarily stable strategies (ESSs) depend on the resource value (V), the cost of injury (D), and the probability that the individual in one role will win (x). Different ESSs can exist even when values of V, D, and x are the same. The characteristics of dominance relations detected by observers may result from the ESSs that the individuals are adopting. The model explains some characteristics of dominance relations, for example, the consistent outcome of contests, the rare occurrence of escalated fights, and the discrepancy between resource holding potential (RHP) and dominance relations, from the viewpoint of individual selection. Received: 7 May 1997 / Accepted after revision: 17 October 1997     

Fabric-filter-supported catalyst for removal of harmful solid and gaseous compounds in municipal waste incinerator exhaust gas: characteristics of NO x reduction

We have investigated a fabric-filter-supported catalyst for removing harmful solid and gaseous compounds simultaneously from municipal incinerator exhaust gas. We studied the ways in which the efficiency of NO _x removal is influenced by filter temperature, gas flow rate, and catalyst content. The reduction of the catalyst content by mechanical reverse washing was investigated, and the state of the catalyst supported in the fabric filter was also observed using a scanning electron microscope. The catalyst supported by the fabric filter showed a removal efficiency above 75% when the filter temperature was 200°C, the gas flow rate was 1 m/min, and the catalyst content of the fabric filter was above 300 g/m². The catalyst was supported uniformly on the fibers of the fabric filter, and fine catalyst particles remained on the fibers after mechanical reverse washing. Received: October 15, 1997 / Accepted: March 19, 1999     

High-performance liquid chromatography with conductimetric detection of perfluorocarboxylic acids and perfluorosulfonates

A rapid and simple method for separating and determining various environmentally harmful perfluorocarboxylic acids and perfluorosulfonates was successfully developed using high- performance liquid chromatography with conductimetric detection, for product and waste management of these compounds at manufacturing and processing sites. Compounds having C(3)-C(8) perfluoroalkyl groups were separated using a Tosoh TSKgel Super-ODS column and a mobile phase consisting of a mixture of methanol and aqueous NaH(2)PO(4) at several mixing ratios. The best detection limits for the compounds ranged from 0.12 to 0.66 mg l(-1) (ppm), and linear calibration graphs were obtained up to 87-109 mg l(-1). The combination of this method with concentration of the sample by solid-phase extraction with cartridges based on styrene-divinylbenzene-copolymer enabled the determination of approximately 50 microg l(-1) (ppb) for compounds with C(4)-C(8) perfluoroalkyl groups. This method was successfully used to monitor the artificial decomposition of the perfluorocarboxylic acid n-C(4)F(9)COOH induced by a photocatalyst.     

Removal of nitrogen oxides with organic amines and metal complexes

Aqueous solutions containing organic amines and metal complexes were applied for the removal of nitrogen oxides. Organic amines were effective for the removal of the mixture composed of nitric oxide and nitrogen dioxide. In particular, methyl and ethyl amines removed these species with 1 : 1 ratio from the mixture at fairly rapid rates. Dinitrogen trioxide (N₂O₃) was suggested to be involved in the course of the removal.Metal complexes removed nitrogen dioxide efficiently. As has been previously reported for a number of inorganic or organic redox systems, it was concluded that the removal of nitrogen dioxide by metal complexes proceeded also by the redox mechanism.Iron (ii) chelate complexes were highly effective for the removal of nitric oxide and this was attributed to a reversible coordination to the complex.     

Erythrocyte supply from the spleen and hemoconcentration in hypoxic yellowtail

Hematocrit and hemoglobin concentration of yellowtail blood elevated more than 30% during severe hypoxia for 35 or 40 min. About 40% of the hematocrit elevation is considered to have been caused by erythrocyte supply from the spleen, and about 60% by hemoconcentration due to water shift out of the circulating plasma. Osmotic swelling of erythrocytes is considered not to have occurred, judging from the constant level in the saturation index of the blood.     

Hydrodynamic forces on emergent cylinders in non-uniform flow

Environmental Fluid Mechanics - The main objective of conducting numerical simulations of flows in rivers with vegetation is to investigate the complex flow dynamics involved in non-equilibrium...     

Distribution of total mercury, methyl mercury and selenium in pod of killer whales (Orcinus Orca) stranded in the northern area of Japan: comparison of mature females with calves

Total mercury (T-Hg) and selenium (Se) concentrations in liver, kidney and muscle from a pod of killer whales including five mature females and three calves stranded in the northern area of Japan were analyzed. In the mature female, contamination level of T-Hg in the liver sample (62.2+/-21.9 microg/wet g) was markedly higher than that in kidney sample and muscle sample. The molar ratio of T-Hg to Se in the liver sample was approximately 1, and those in the kidney and muscle samples were markedly lower than 1. These results suggest that the formation of HgSe compound increases the hepatic accumulation of mercury (Hg). In contrast, contamination level of T-Hg in the calf organs was much lower than that in the mature female organs. These results suggest that the transfer of Hg from the mother to the fetus via placenta and/or to calf via milk is trace.     

Synthesis of novel polymer type sulfoxide solid phase combined with the porogen imprinting for enabling selective separation of polychlorinated biphenyls

We developed a novel polymer type sulfoxide-modified solid phase enabling to achieve selective separation of polychlorinated biphenyls (PCBs) from insulation oil. In this study, firstly we prepared base-polymer based on the concept of the molecular imprinting to capture PCBs in selectively, then, the sulfoxide groups were modified on the pore surface of base-polymers by changing preparation methods. As results of liquid chromatographic analyses for the polymers as columns, the base-polymer prepared by xylene as a porogenic solvent showed selective retention ability for chlorinated aromatic compounds by the porogen imprinting effect. Additionally, the polymer-type sulfoxide solid phases showed highly retention ability for PCBs by increasing amount of introduced sulfoxide groups. Consequently, the results of separation of PCBs comparing to insulation oil suggested that the prepared solid phase can be used for the selective separation of PCBs at the same level as a commercially available media utilized for the regulated method.     

Electrolytic aminated carbon materials for the electrocatalytic redox reactions of inorganic and organic compounds

Some kinds of amine groups can be introduced to the glassy carbon surface by the electrode oxidation of the carbon electrode surface in ammonium carbamate solution, and this amine groups modified electrode is named as an aminated glassy carbon electrode. The existences of not only primary amine but also secondary and tertially amines were confirmed by X ray photoelectron spectroscopy. The applications of the aminated carbon material for the electrocatalytic reductions of oxygen, hydrogen peroxide, and organic compounds such as quinones were carried out, and the effects of amination on the formation of electrocatalytic sites for many species were revealed. The electrocatalyzed cyclic voltammograms of metal ions and metal chelate compounds obtained by aminated glassy carbon electrodes are also discussed. Moreover, we intend to describe that the aminated carbon electrode can exhibit the large reduction waves of inorganic oxoacids such as N0₂? or bromide ion. The introduced functional groups containing nitrogen atom can change the distribution of the electron densities of the graphite carbon surface, and this specific electron distribution environment may generate the various electrocatalytic activities.