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The Briggs Rauscher reaction (BR reaction) is one of the famous oscillating reactions; the aqueous mixture of KIO3, H2SO4, H2O2, C3H4O4, MnSO4, and starch exhibit color change between yellow and blue-purple repeatedly. The blue-purple color formation is due to the iodine test reaction caused by inclusions of polyiodides such as I3- and I5- in the helical structure of starch. Therefore, starch has been regarded as only an indicator in the BR reaction. But our seniors have found that the oscillation did not last without starch. They hypothesized that starch’s linear helical framework is necessary to elongate the lifetime of the oscillating reaction. If this hypothesis is correct, similar BR-type oscillations must be observed when other polymers with helical structures are used instead of starch. We found the literature which reports that polyvinyl alcohol (PVA) forms a helical structure and indicates the iodine test reaction. In our research, we studied the BR reactions using PVA, with different saponification degrees and viscosities. First, we studied the correlation between the structural features of PVA and the iodine color reaction by spectroscopic approach, exhibiting that PVA with low saponification form helical structures and show the iodine color reactions, which gives red color solutions. Second, we found that additions of the helical-structured PVA to the reaction solution instead of starch induces the BR-type oscillating reactions, while PVA without helical structure induces only a few numbers of oscillations. This is the world-first example of the oscillating reaction using PVA. The oscillation that lasted for 6 minutes with 23 oscillations was almost the same as that of the general BR reaction using starch. We concluded that the polymers with helical structures are intrinsic to elongate the lifetime of the BR reaction. Furthermore, we found that the addition of K3[Fe(CN)6], which has a high redox activity, in the reaction solution with PVA drastically elongated the lifetime (50 min) and increased the numbers of the oscillations (nearly 100 times). This result suggests that the oxidation-reduction reactions by the ferricyanide ion promotes the redox process of iodine and iodide ions.

Inhibitory effects of the secondary metabolite of actinomycete were examined on cell cycle of the yeasts of S. pombe and S. cerevisiae. The secondary metabolite was obtained from cultivation of the actinomycete isolated from the soil of Owakudani in Hakone, Japan. The fifth fraction of the secondary metabolite by ODS column separation (HK-T5), which was soluble to pure methanol, was used in the present experiments. The HK-T5 brought about the delay of forming colonies of S. pombe for about 11 days compared to that cultivated without the HK-T5. The delay of the colony formation was longer for the S. pombe cultivated with more amount of the HK-T5. The cultivation with HK-T5 also brought about the extension of the lifespan of the S. pombe for more than 10 weeks in a liquidus medium. The cell life recovered the ordinary manner by removal of the HK-T5, meaning that the activities of the HK-T5 is reversible. These facts confirm the suppression of cell cycle, and the delay of cell growth by the HK-T5. These phenomena were similarly observed for S. cerevisiae. Comparison of the action of HK-T5 with hydroxyurea, which is an anticancer drug inhibiting the cell cycle at S phase, clarified that the inhibitory action of HK-T5 worked at the phase earlier than S phase. The combined effects of HK-T5 on the cell cycle were evaluated with triamcinolone acetonide (TA), or aspirin, the former of which is a drug synchronizing cancer cells in S phase, and the latter keeping human cells in G1/G0 phases. The combined use of HK-T5 with TA synchronized the cells at the phase slightly proceeding from G1 to S phase without toxicity. On the other hand, the combined use with aspirin made the inhibitory effect of HK-T5 inactive. Hence, the HK-T5 is attractive as a drug for the extension of cell lifespan, and anticancer therapy.

Inhibitory effects of the secondary metabolite of actinomycete were examined on cell cycle of the yeasts of S. pombe and S. cerevisiae. The secondary metabolite was obtained from cultivation of the actinomycete isolated from the soil of Owakudani in Hakone, Japan. The fifth fraction of the secondary metabolite by ODS column separation (HK-T5), which was soluble to pure methanol, was used in the present experiments. The HK-T5 brought about the delay of forming colonies of S. pombe for about 11 days compared to that cultivated without the HK-T5. The delay of the colony formation was longer for the S. pombe cultivated with more amount of the HK-T5. The cultivation with HK-T5 also brought about the extension of the lifespan of the S. pombe for more than 10 weeks in a liquidus medium. The cell life recovered the ordinary manner by removal of the HK-T5, meaning that the activities of the HK-T5 is reversible. These facts confirm the suppression of cell cycle, and the delay of cell growth by the HK-T5. These phenomena were similarly observed for S. cerevisiae. Comparison of the action of HK-T5 with hydroxyurea, which is an anticancer drug inhibiting the cell cycle at S phase, clarified that the inhibitory action of HK-T5 worked at the phase earlier than S phase. The combined effects of HK-T5 on the cell cycle were evaluated with triamcinolone acetonide (TA), or aspirin, the former of which is a drug synchronizing cancer cells in S phase, and the latter keeping human cells in G1/G0 phases. The combined use of HK-T5 with TA synchronized the cells at the phase slightly proceeding from G1 to S phase without toxicity. On the other hand, the combined use with aspirin made the inhibitory effect of HK-T5 inactive. Hence, the HK-T5 is attractive as a drug for the extension of cell lifespan, and anticancer therapy.

In order to recycle disposable diapers, we investigated the conditions where sodium sesquicarbonate (Chemical formula Na2CO3・ NaHCO3・ 2H2O hereinafter called sesqui) precipitates selectively from sodium carbonate and the conditions for high yield. For the selective precipitation of sesqui, we defined the time required for the reaction solution to pass through the sesqui precipitation area in the Na2CO3-NaHCO3-H2O phase diagram (45°C) as Δ t. As a result, we revealed that Δt is involved in the selective precipitation of sesqui, and that we can synthesize sesqui without the expensive addition of L-Arginine as used in a previous research. Also, we proposed the “Stay method”, in which the supply of CO2 is stopped for 30 minutes to the lengthen the Δ t, and found that we could synthesize sesqui selectively even under conditions in which sodium bicarbonate is likely to be precipitated as well. Regarding the high yield of sesqui, the yield was greatly improved by the common ion effect of Na by adding NaOH to the reaction solution, sesqui synthesis by repeated reactions with CO2, and sesqui recovery by adding the anti-solvent ethanol, reaching a sesqui conversion rate of 95%. This means 109 g of sesqui can be synthesized from 100 g of Na2CO3. Moreover, we confirmed that these synthesized samples have almost the same detergency as commercial sesqui. We did a test calculation to reveal the usefulness of this research. First, if diaper recycling technology is put into practical use and all used diaper waste in Saijo City can be recycled, a reduction of 534 t/year of used diaper waste can be expected. This corresponds to a 2.3% reduction in Saijo City's waste output. From the ash that would ultimately remain after being recycled, we expect up to 35.3 t/year of synthesized sesqui using our experimental method. In addition, a CO2 reduction of 8.2 t/year is possible in the process, which is about equivalent to the volume of one gymnasium.

We elucidated the cause of the phenomenon, in which silver deposits on a bamboo charcoal when the bamboo charcoal is soaked in an AgNO3 water solution. From the experimental results, we considered that the hydrogen which is generated while the bamboo wood is carbonized is chemisorbed as C-H bonds on the surface edge of charcoal (the end of the carbon), and that these hydrogen atoms become hydrogen ions,which then reduce the silver ions and deposit silver. In addition, we created a graph of the mass of deposited silver versus the mass of charcoal, and the graph showed that the mass of deposited silver was strongly correlated with the surface area calculated from the mass of the charcoal. Besides, we showed that charcoal can be used in applications for the treatment of inorganic liquid waste, depositing metals from inorganic liquid waste by bamboo charcoals. Also, the charcoal is used for interior decoration because of its deodorizing effect and beauty. In our study, we create a work of art used silverdeposited charcoal with a motif of Karesansui (Traditional Japanese rock garden).