Search

金沢大学理工研究域サステナブルエネルギー研究センター, The present study is an attempt for assessing the relationship between iron deficiency and discoloration in Undaria pinnatifida sporophytes. First, thallus discoloration and the decrease in photosynthetic pigment contents were examined in Undaria pinnatifida by employing an indoor iron-deficiency experiment. When Undaria pinnatifida sporophytes were cultured under iron-deficient conditions, which the iron concentrations were between 2 and 5 μg/L, the growth decreased, the thalli became discolored, and the photosynthetic pigment contents decreased. Iron deficiency caused the sporophytes to become lighter (L*) and less red (a*). Therefore, it appears that iron deficiency induces the discoloration of Undaria pinnatifida sporophytes, similar to how nitrogen and phosphorus deficiencies perform. Next, we investigated how the mechanism involved in the addition of iron affects the discolored Undaria pinnatifida sporophytes due to iron deficiency by performing an indoor iron-addition experiment. Undaria pinnatifida sporophyte growth, thallus color, and photosynthetic pigment content were all restored by the addition of dissolved iron solution, which the concentrations were between 10 and 50 μg/L. Iron addition made the sporophytes recover their lightness (L*) and redness (a*). In addition, the color was restored more quickly as the amount of added iron was increased. The discoloration of iron-deficient Undaria pinnatifida sporophytes can thus be restored by iron addition.

金沢大学理工研究域機械工学系, Discoloration of nori, Porphyrayezoensis, is a terrible economic problem for the fisheries. One of the reasons for the discoloration of nori is suggested the decreasing concentrations of nutrients, nitrogen and phosphorus. The red tide by some diatom, rainfall, and so on cause the bad balance of water quality. Recently, it was showed that iron is important for the color maintenance of nori. Sea desertification, isoyake. can be seen in some Japanese coastlines. It is suggested that one of the reasons for this phenomenon is the decreasing concentrations of nutrients and iron. Against this backdrop, the fertilizer has been produced using steel-making slag and humus soil, which can stably supply iron and some nutrients. We have demonstrated the effect of the fertilizer on algal growth in Japan. In this study, we studied the effect of the fertilizer to the growth of nori by the mesocosm experiment Both of experimental tanks for the mesocosm were set up nori-meshes. and 60 kg fertilizer in one side, while the other tank was no fertilizer as a control. We surveyed the concentration of nutrients and trace metals, and the growth of nori. As a result, in the fertilizer containig tank the concentration of nitrogen, phosphorus and iron were raised, in brief the nutrients and iron eluted from the fertilizer. And only in the fertilizer containig tank, nori grew up over 10 cm in length. On the other hand, we could not identify the growth of nori by visual observation in the control tank, fertilizer not containing tank.

金沢大学理工研究域機械工学系, The use of steelmaking slag as a recycled material is being progressed in coastal waters for marine environment improvement, by exploiting the characteristics of steelmaking slag. However, regarding its use in coastal waters, there are as yet no criteria for determining which bioassay should be used for assessing its effect on marine organisms. As a method of voluntary quality control of steelmaking slag, we selected a suitable battery of bioassays. The acute toxicity of steelmaking slag leachate on a copepod (Tigriopus japonicus) and a luminescent bacterium (Vibrio fischeri) was evaluated. As a result of the bioassay tests on some types of steelmaking slag, the leachate from the steelmaking slag with the pH preadjustment carbonation process showed smaller pH increases and no inhibitory effect on the marine organisms evaluated. On the other hand, the leachate from the steelmaking slag without carbonation showed an inhibitory effect on both organisms, as shown by an increase in its pH up to 12. This inhibitory effect was observed only in T. japonicus even when the pH was reduced to 8. The inhibitory factors of such leachate on T. japonicus and luminescent V. fischeri were examined. No hazardous substances were detected in the leachate. However, the calcium and magnesium concentrations of the leachate markedly changed compared with those of seawater. When the calcium concentration of the leachate was adjusted to that of seawater, the inhibitory effect on T. japonicus almost disappeared. Therefore, calcium concentration changes brought about by pH changes were considered to be the main inhibitory factors in the leachate. When bioassays with marine organisms are used to evaluate a recycled material such as steelmaking slag, the calcium and magnesium concentrations of the leachate should be carefully considered.

The purpose of this study was to investigate whether high school students who desired the same educational status as their parents (consistent group) showed higher career awareness than those who desired the different educational statuses from their parents (inconsistent group). Participants were 316 tenth-graders, 290 eleventh-graders, and 278 twelfth-graders. They completed the Career Awareness Scale to measure four areas of career awareness; interpersonal relationship, information utilization, future planning, and decision-making. They also completed the Parental Support Scale and Desired Educational Status Questionnaire. The consistent group showed higher parental support score and lower decision-making score than the inconsistent group. Additionally, high school students who desired higher level of educational status showd higher information utilization and decision-making scores than those who desired lower level of educational status. These results were discussed in relation to parent-child relationship.

金沢大学理工研究域機械工学系, The control of phosphorus release from eutropHicated coastal sediment by a carbonated steelmaking slag was examined. Batch experiments showed the following. Without slag addition, the pH, DO and ORP of seawater easily decreased with the progress of coastal sediment corruption. Moreover, phosphorus release from coastal sediment occurred rapidly. On the other hand, with steelmaking slag addition, the decreases in pH and DO were inhibited and the high ORP values of seawater were maintained. Phosphorus release from coastal sediment was clearly inhibited by slag addition. Even when the carbonated steelmaking slag was compared with sand, phosphorus release from coastal sediment was further improved. In the mechanism of phosphorus release control through steelmaking slag addition, it was considered that a carbonated steelmaking slag promotes calcium hydroxyapatite (HAP) generation induced by the high Ca2+ concentration of seawater. Furthermore, continuous experiments for more than 300 days showed that pH control and phosphorus release control from coastal sediment by carbonated steelmaking slag addition were maintained for a long term.

金沢大学理工研究域機械工学系, The iron-oxidizing bacterium, Thiobacillus ferrooxidans, is not halotolerant and cannot oxidize ferrous ions (Fe2+) to ferric ions (Fe3+) in electroplating wastewater containing high concentrations of chlorine ions. T. ferrooxidans cannot be used for the treatment of such electroplating wastewater. The acclimation of iron-oxidizing halotolerant bacteria has been studied to treat electroplating wastewater containing ferrous ions and a high concentration of chlorine ions. Iron-oxidizing bacteria that are halotolerant and able to oxidize Fe2+ to Fe3+ were obtained from the activated sludge of a steel works coke-oven wastewater treatment plant. A long-term experiment using artificial wastewater containing 20,000 mg · l-1 chlorine ions showed the stable performance of the Fe2+ oxidation ability by iron-oxidizing bacteria acclimated to seawater. It seems that the acclimated iron-oxidizing bacteria can be used for the treatment of electroplating wastewater. An analysis of genomic DNA extracted from the acclimated sludge of the reactor showed the existence of an analog of the iron-oxidizing bacterium, Thiobacillus prosperus.

金沢大学理工研究域機械工学系, Wastewater from electroplating plants contains several metallic ions such as iron, nickel and zinc. In general, neutralization followed by sedimentation has been used for the treatment of electroplating wastewater. However, this process results in the production of large amounts of heavy metal sludge. The objective of this research is to achieve selective metal separation, metal recovery and reduction in sludge volume. We have examined the feasibility of a biological process using iron-oxidizing bacteria in the treatment of electroplating wastewater from steel works. It was proved that iron-oxidizing bacteria acclimated from activated sludge have the ability to oxidize ferrous ion (Fe2+) to ferric ion (Fe3+) in electroplating wastewater. A bioslurry reactor, which promotes both Fe2+ oxidation and Fe(OH)3 generation in the pH range from 3.0 to 4.0, showed an almost complete Fe2+ oxidization after 2 hours of hydraulic retention time. The produced Fe(OH)3 was recovered by sedimentation in the same pH range with almost no trace of nickel or zinc. Nickel and zinc hydroxides were easily recovered by sedimentation at pH 9.0.

金沢大学理工研究域機械工学系, 日本下水道協会への転載許可申請済_2022.03

金沢大学理工研究域機械工学系, Two ELISA methods were investigated for the quantitative detection of viability and infectivity of Cryptosporidium parvum oocysts. One is to detect the sporozoites attached to the cell surface, and another is to detect the oocysts developing in host cell. It was thought that the former method, named “Fixed-cell” ELISA, could assess the viability of oocysts, and the latter method, named “Living-cell” ELISA, could assess the infectivity of oocysts. In both ELISA systems, the resulting optical density was related to the number of oocysts inoculated. Inactivation of oocyst by ultraviolet (UV) irradiation was evaluated using these two ELISA systems. One-log reduction in infectivity of oocysts was achieved by 10 mW·s·cm-2 of UV irradiation. At this UV dose, no reduction in viability determined by “Fixed-cell” ELISA was observed.

金沢大学理工研究域機械工学系, The application of the sulfur oxidizing bacteria to wastewater including high concentration of nitrate was basically examined by the experiment using artificial wastewater. As a result, the following were clarified.Sulfur oxidizing bacteria having the denitrification function was acclimated by using artificial wastewater containing only nitrate as a nitrogen source from the activated sludge of the sewage plant in about three weeks This bacteria was able to remove nitrogen from artificial wastewater which included nitrate of 900-1300mg-N·l-1 under the condition of 1.5-3 hours of HRT (The water temperature: 20°C). This sulfur source was thiosulfate and 3.5-4 was suitable in the S/N ratio. As for the acclimated sulfur oxidizing bacteria, the denitrification rate was presumed to be large since it was easy to make self-immobilized and was maintained to be hightly concentrated in the reactor. On the other hand, it was thought that there was a problem in the maintenance management by accumulating sulfur when an excessive high load operation was continued.

金沢大学理工研究域機械工学系, For developing water treatment system to prevent waterborne Cryptosporidiosis, it is necessary to estimate the inactivation of Cryptosporidium. Recently, cell culture model has developed into a tool that can be used for assessing the viability and/or infectivity of Cryptosporidium oocysts. In this study, we investigated to develop quantative and sensitive detection method for determining the infectivity of Cryptosporidium oocysts by combining cell culture with enzyme-linked immunosorbent assay (ELISA). Human ileocecal epitherial cells (HCT-8), which were seeded in gelatin-coated 96-well plates at the density of 1 × 104 cells · well-1 and incubated at 37°C for 48h, were infected with the oocysts. After inoculation, HCT-8 cells were re-incubated with fresh culture media at 37°C for 48h, then were processed for ELISA. The absorbance values in ELISA were increased in an inoculating dose-dependent manner. In the experimental condition, the number of the oocysts from 1 × 102 to 3 × 104 per well was quantitatively detected.

金沢大学理工研究域機械工学系, 日本下水道協会への転載許可申請済_2022.03

梅津(2007)は, 社会科教育で育成する能力に関して「社会科学力の構造と関心・意欲・態度との関係モデル」を提唱している。本研究ではこのモデルに基づいて, 社会科学力の一つである批判的思考力と社会科学力の関連要因である社会的事象に対する関心・意欲と社会的態度について次の2点を検討した。(1)批判的思考力, 社会的事象に対する関心・意欲および社会的態度の各得点が中学校の学年進行に伴って上昇傾向にあるか否か。(2)批判的思考力の育成が社会的事象に対する関心・意欲の促進や社会的態度の獲得に影響するか否か。中学生のデータに基づく分析の結果, いずれの得点においても有意な学年差はほとんど見出されなかった。しかし, 群間比較とモデル検討の結果, 批判的思考力が高い生徒ほど社会科の学習や周囲の人々に対して高い関心・意欲を示し, 身の回りや社会的な事柄について積極的に理解しようとする社会的態度をもつ傾向にあることが明らかになった。

金沢大学理工研究域機械工学系, 2009年度 日本水産工学会 学術講演会 講演論文 Proceedings of Annual Meeting of the Japanese Society of Fisheries Engineering, 2009, Date : May 23, 2009 - May 25, 2009

金沢大学理工研究域機械工学系