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Capability of the recycling of high strength and high fracture toughness yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP) sintered body utilizing “low-temperature annealing degradation” phenomenon was investigated. Hydrothermal treatment was employed to induce the phase transformation from tetragonal to monoclinic zirconia and to disintegrate the Y-TZP sintered body. 3 mol% Y2O3–ZrO2 specimens sintered at 1,550 °C and more were disintegrated without leaving the original appearances when the treatment temperature was between 200 °C and 400 °C. The size of the disintegrated fragments of Y-TZP sintered body was much affected by hydrothermal treatment conditions. Only with hydrothermal treatment and simple ball milling, the sintered body was pulverized into the primary particle level. This technique is expected to apply to a sustainable recycling system for the zirconia ceramics, which restrains an energy consumption compared to crushing zirconia using mechanical procedures.

Double layered photoreceptors using low ionization potential molecules as the carrier transport layer (CTL) have been investigated. The ionization potential (l p ) was estimated by the ? technique calculation and the polarographic oxidation potential. A good correlation was obtained between the photosensitivity and the l p value of the CTL. However this result could not be explained simply by the energy level misfit of the carrier generation layer (CGL) and the CTL. Styryl dye bases, cyanine dye bases, and oxazoles were selected as CTL materials on the basis of their transparency and high solubility in polymers. The photoreceptors using these CTL materials showed much higher sensitivities than the well-known polyvinylcarbazole- trinitrofluorenone (PVK-TNF) system. The peak value of the spectral sensitivity in the system composed of an oxazole, OX-2, and a disazo pigment, chlorodianeblue (CDB), was 0.17 m 2/mJ at 650 nm.

3′-Deoxyseldomycin 5 (2), 2′-deamino-3′-epiamino-3′-deoxyseldomycin 5 (14), and 2′,3′-epimino-2′-deamino-3′-deoxyseldomycin 5 (15) were prepared from seldomycin 5 (1). Treatment of hexa-N-ethoxycarbonyl (ecb)-3′-O-tosylseldomycin 5 with sodium borohydride in DMSO gave the corresponding N-ecb-derivatives of 2, 14, and 15. Removal of the ecb groups of these compounds with aq potassium hydroxide gave the free bases 2, 14, and 15, respectively. Structure determination of the products was performed by means of MS, CMR, PMR, and chemical reactions. It was found that 2 exhibits a more potent and broader antibacterial activity than the parent compound 1, and 14 shows unique antibacterial spectrum against resistant strains, whereas 15 has almost no activity.

3′-Episeldomycin 5 (7) was synthesized from seldomycin 5. Reaction of hexa-N-ethoxycarbonylseldomycin 5 (2) with o-nitrobenzenesulfonyl chloride gave penta-N-ethoxycarbonylseldomycin 5-2′,3′-epicyclic carbamate (3) in one step. Hexa-N-ethoxycarbonyl-3′-O-tosylseldomycin 5 or hexa-N-ethoxycarbonyl-3′-O-mesylseldomycin 5, prepared from 2, was also converted into 3 by being heated in weakly basic solvents such as N,N-dimethylformamide or pyridine. Compound 3 was hydrolyzed to give 7. Structure of 7 was confirmed by PMR, CMR, MS, and Δ[M] values. Compound 7 was found to be active against resistant bacteria which carry 3′-O-phosphorylating enzymes. Δ[M] values for vicinal amino groups were shortly discussed.

2-Aminoethyl, glycyl, (S)-4-amino-2-hydroxybutyl and (S)-4-amino-2-hydroxybutyryl groups were introduced to the 2'-amino group of 4-N-[(S)-4-amino-2-hydroxybutyl]fortimicin B (2). All of the derivatives of this type prepared showed antibacterial activity almost as strong as fortimicin A (1) and were also active against fortimicin A resistant bacteria which can inactivate fortimicin A by producing an inactivating enzyme AAC(3)-I.

The 1, 2' or 6'-amino group of fortimicin A was alkylated or acylated and the antimicrobial activities of the derivatives were compared with each other. 2'-N-Substituted fortimicins A were active against the fortimicin A resistant strain which produced AAC(3)-I. AAC(3)-I is the only enzyme which can inactivate fortimicin A. Among the derivatives prepared in the present study, 2'-N-[(S)-4-amino-2-hydroxybutyl]fortimicin A showed stronger activity than fortimicin A.

播種状表在性光線性汗孔角化症 (DSAP) に併発した多発性の表皮内癌の2例を報告した。第1例は66歳男性で両手背にBowen病を生じ, 第2例は81歳男性で両手背, 頭部に光線角化症を多発して認め, 両者ともに表皮内癌の周囲に多数のDSAPを散在していた。DSAPは巨大汗孔角化症や局面型汗孔角化症とともに皮膚癌の発症母地であり, さらに日光による発癌を呈しやすい病態であると考えた。

7-Deoxy-4(R)-dihydrospectinomycin (7) has been prepared and its structure firmly established by proton magnetic resonance and high resolution mass spectrometry. This spectinomycin analog is devoid of antibiotic activity.

1,6,8-Trimethoxy-3-hydroxymethyl-2-naphthoic acid lactone (IV) was synthesized from benzoic acid in 21 steps. This lactone (IV) was completely identical with authentic dimethyl α-sorigenin, obtained by the methylation of natural α-sorigenin. Herewith the structure of α-sorigenin was confirmed to be 1,8-dihydroxy-6-methoxy-3-hydroxymethyl-2-naphthoic acid lactone (III).

Fortimicins C, D, and KE are new aminocyclitol antibiotics produced by a mutant of fortimicin-producing organisms. Their structures have been determined by 1H and 13C NMR and mass spectra and chemical degradations. Fortimicin C is 4-N-hydantoylfortimicin B, fortimicin KE is 6'-demethylfortimicin B, and fortimicin D is 4-N-glycylfortimicin KE. The last two antibiotics have purpurosamine C instead of 6-epi-purpurosamine B.

7-Epi-spectinomycin (9) and 7-epi-4(R)-dihydrospectinomycin (10) have been prepared and their structures firmly established by proton magnetic resonance. Both of these spectinomycin analogs are devoid of antibiotic activity.

The four amino groups of fortimicin B(4) could be differentiated from each other and 2'-N-benzyloxycarbonyl-, 2', 6'-di-N-benzyloxycarbonyl-, 2'-N-tert-butoxycarbonyl-, 6'-N-tert-butoxycarbonyl- and 2', 6'-di-N-tert-butoxycarbonyl-fortimicin B (7, 8, 16, 18, 17) were prepared from 4. From these fortimicin B derivatives, selectively protected fortimicin A derivatives 13, 15, 21, 22 and 25 were prepared by combination of procedures of benzyloxycarbonylation or tert-butoxycarbonylation, 4-N-glycylation.

Among the new aminoglycoside antibiotic family for fortimicins, components A, C and D have higher activity compared to their 4-N-deacylated components B and KE. Synthesis and antibacterial activities of 4-N-acyl- and 4-N-alkyl-fortimicin B derivatives are described. 4-N-Acylfortimicin B's, which are relatively unstable in alkaline conditions, were converted to stable 4-N-alkyl derivatives with diborane. The activity is greatly affected by the 4-N-substituents, and the presence of hydrophilic group(s) is necessary to confer activity on the derivatives. 4-N-(2-Aminoethyl)-, 4-N-(4-amino-2-hydroxybutyl)- and 4-N-(2-hydroxy-4-methylaminobutyl)-fortimicin B are the most potent compounds among them.