Swelling of Crosslinked Polyelectrolytes Composed of Vinyl alcohol and Acrylic acid Units

Crosslinked copolymers of different polymer composition and density of crosslinking points were prepared by copolymerization of methylacrylate and vinylacetate in the presence of divinylbenzene as a crosslinking agent, the copolymers then being converted by saponification into polyelectrolytes containing carboxyl groups , along the chains. The degree of swelling of the sodium salts of these polyelectrolytes was measured in pure water. The osmotic coefficients in water were estimated from the degree of swelling in water, taking into consideration the effect of large deformation of the unit chains on the contractile pressure of the gel. The calculated values of the osmotic coefficient were very small and comparable to those previously found for the linear polyelectrolyte composed of the same components. The characteristic features of the results were discussed by considering the factors which may influence the activity of the counter-ions, such as the hydrolysis of the polyelectrolytes, the counter-ion fixation and the excluded volume effect of the macro-ions

海洋性珪藻におけるCO₂濃縮及びCO₂感知機構の解析

関西学院大

Adsorption of Bovine Serum Albumin and γ-Globulin on Chitosan Membrane

Adsorption of proteins on chitosan, which has positively charged proups, was investigated. The amount of adsorption depended on pH values and showed the maximum at the isoelectric point of BSA (pH 4.5-5.0) as was recognized in non-charged polymer membl-anes. Also it depended on an ionic strength, which affected the maximum point as well as the amount itself. It was considered that the positive charge of chitosan may affect the isoelectric point of BSA at which the smallest lateral interaction appeared to make the compactest form of BSA molecule. Whereas, contrary to the general tendency observed at much lower concentration of BSA, the amount of maximum adsorption decreased as the ionic st.rength decreased. This suggests that at relatively high concentration, the reduction of shielding effect of ions may give the increase of repulsion between BSA molecules rather than that of interaction between BSA and chitosan molecules. The adsorption of γ-globulin was studied, too. Futhermore, the adsorption of chitosan onto a silk fiber as substitute for human hair was studied to result in the usefulness as the rinsing agent

High-Tc ramp-type Josephson junctions on MgO substrates for Terahertz applications

The authors successfully fabricated high-Tc ramp-type junctions with PrBa2Cu3-xGaxO7-δ (PBCGO: x=0.1, 0.4) barriers on MgO substrates. The junctions showed resistively shunted Josephson junction (RSJ)-like I-V curves with thermally and voltage activated conductivity. The IcRn products for these junctions scaled very well with the Ga-doping. Maximum response of the junctions for 100-GHz millimeter-wave irradiation could be observed up to 12 mV corresponding to 6 THz. Using far infrared laser radiation, we confirmed a terahertz (THz) response of these junctions. These results show promise for THz-wave applications of ramp-type Josephson junctions

COMPARISON OF THE ABUNDANCE OF PREY ANIMALS FOR ORIENTAL STORKS IN A BIOTOPE AND LOTUS FIELDS IN NARUTO CITY, TOKUSHIMA PREFECTURE, JAPAN.

本研究では，鳴門市に造成されたビオトープが，コウノトリの餌場として機能するかを明らかにするため，周囲の飛来回数の異なるレンコン田とコウノトリの餌生物量を比較した．餌生物は，すくい採りとペットボトルトラップによって採集した．調査の結果，ビオトープで採集された餌生物の湿重量は，コウノトリの飛来回数が多いレンコン田より小さかった．レンコン田で採集された生物は，アメリカザリガニやウシガエルといった外来種が大半を占めた．これらの生物はコウノトリの主要な餌となり得るが，在来種を捕食するなど，在来生態系に負の影響を与えることが懸念される．今後のビオトープ管理においては，在来種の生息に適した環境づくりとともに，外来種の侵入・拡大防止を両立する取り組みが重要であると考えられた．In order to clarify whether the biotope created in Naruto City functions as a feeding sites for storks, this study compared the amount of stork prey in a lotus root field and a biotope created with different numbers of storks flying to the field. Prey organisms were collected by scooping and plastic bottle traps. The results showed that the wet weight of prey organisms collected in the biotope was smaller than that in the lotus root fields, where the storks visited more frequently. The majority of organisms collected in the lotus root fields were non-native species such as American crayfish and bullfrogs. These organisms are the main food source for storks, but there is concern that they may have a negative impact on native ecosystems, for example, by preying on native species. In future biotope management, it is important to create an environment suitable for habitat of native species as well as to prevent the invasion and spread of non-native species