Bis-[dipyrido[3,2-a:2',3'-c]phenazine)2(1,10-phenanthroline)2Ru2] 2+ complexes (bis-Ru(II) complexes) tethered by linkers of various lengths were synthesized and their binding properties to DNA investigated by normal absorption and linear dichroism spectra, and fluorescence techniques in this study. Upon binding to DNA, the bis-Ru(II) complex with the longest linker (1,3-bis-(4-pyridyl)-propane), exhibited a negative LD r signal whose intensity was as large as that in the DNA absorption region, followed by a complicate LD r signal in the metal-to-ligand charge transfer region. The luminescence intensity of this bis-Ru(II) complex was enhanced. The observed LD r and luminescence results resembled that of the [Ru(1,10-phenanthroline)2dipyrido[3,2-a:2',3'-c]phenazine] 2+ complex, whose dipyrido[3,2-a:2',3'-c]phenazine (dppz) ligand has been known to intercalate between DNA bases. Hence, it is conclusive that both dppz ligands of the bis-Ru(II) complex intercalate. The binding stoichiometry, however, was a single intercalated dppz per ~ 2.3 bases, which violates the "nearest binding site exclusion" model for intercalation. The length between the two Ru(II) complexes may be barely long enough to accommodate one DNA base between the two dppz ligands, but not for two DNA bases. When the linker was shorter (4,4'-bipyridine or 1,2-bis-(4-pyridyl)-ethane), the magnitude of the LD in the dppz absorption region, as well as the luminescence intensity of both bis-Ru(II) complexes, was half that of the bis-Ru(II) complex bearing a long linker. This observation can be elucidated by a model whereby one of the dppz ligands intercalates while the other is exposed to the aqueous environment.

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In this study, silk gland powder of silkworm were investigated to see the possibility for baby powder cosmetics materials. To test possibility as a baby powder cosmetics, total content rate of amino acids, DPPH free radical scavenging assay, MTT assay, and clinical trial were done. According to the result of the analysis of the amino acids of silk gland powder, serin (26.77%) content was the highest and asparatic acid (15.47%), and glycine (9.62%) were followed. DPPH free radical scavenging activity of silk gland powder was lower than vitamin C by 82.3% and 97%, respectively, which is relatively good. Moisture effect were increased in silk gland powder compared to control cosmetics by 50%. Also, silk gland powder was classified as a practically non-irritating material based on the score 0.05 of primary irritation index. Thus, these results suggest that silk gland powder of silkworm may have beneficial properties as a material for baby powder cosmetics.

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