We have been screening biologically active peptides from the ganglia and heart tissues of the African giant snail, Achatina fulica. Two novel peptides were isolated and named achatin- I and fulicin. Each peptide contained a D-amino acid r esidue at the second position. Achatin- I enhanced the cardiac ac tivity by exciting the heart excitatory neuron in the central nervous system and peripherally by increasing the frequency and the amplitude of t he ventricular beat. Fulicin potentiated the contraction of the penis retractor muscle. Fulicin-like immunoreactivities were found in t he nerve fibers innervating the mu scle, and fulicin-like substances were scattered in the muscle. Fulicin was suggested to be involved in the regulation of t he muscle contraction. The cDNA encoding the precursor protein of f ulicin revealed th at the D-Asn residue of fulicin was encoded by the normal codon. It was suggested that novel post-trans lational L-/D-isomerization process was involved in the biosynthesis of fulicin. Three possible roles of Damino acids have been discussed as follows: 1) Specific stereostructures which may be suitable for binding to receptor molecules can be stabilized by the presence of D-amino acid residue.2) The D-amino acid residue may modulate the biological activity of the peptide, thereby generating biological diversity.3) The presence of D-amino acids may increase the resistance to enzymatic degradation and prolong biological life of peptides. Since we have found the peptide which may not be involved to three categories mentioned above, more discussion will be necessary to clarify the physiological roles of D-amino acids.

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To investigate the origin of deterioration of H-ZSM-5 and H-mordenite, the active catalysts of reactions in the aqueous solution, such as cyclohexene hydration and trioxane sythetic reaction from formalin, the stability of both zeolites was studied under the hydrothermal conditions in the presence of only water at 130 °C.
The results showed the decreasing of the catalytic activity of trioxane synthetic reaction on the both zeolites.
The origins of deterioration of the activity were investigated by the change of the amount of acid and the hydrophobic nature determined by means of the adsorption method of aqueous 1-propanol solution.
On H-ZSM-5, the amount of acid was decreased by dealumination from the framework under the hydrothermal conditions at 130 °C, but the hydrophobic nature was not changed. It may be concluded that the decreasing of the activity was chiefly caused by reducing the amount of acid.
Dealumination of H-mordenite under the hydrothermal conditions was large at SiO₂/Al₂O₃ ratio of 57and very small at 90. However, the amount of acid in the pore within 12-membered oxygen rings, the ac-ti ve site, increased in the both mordenites. But the hydrophobic nature of two mordenites largely reduced. We may, therefore, reasonably conclude that the lowering of the hydrophobic nature was responsible for decreasing the activity of mordenite.

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To clarify the dealumination behavior of zeolite during steaming, HZSM-5 zeolites with various degrees of dealumination were prepared by steaming and thermal treatment. The dealuminated zeolites were characterized by using FT-IR and water vapor adsorption. It was found that the dealumination rate is strongly dependent on the water vapor pressure. It was also found that the dealumination of HZSM-5 zeolite by steaming consists of two steps at least; the first step is a partial hydrolysis of four A1-O bonds of the framework aluminum, and the second step is a complete release of the alumin um from the zeolite framework.
Adsorption of n itrogen and water vapor was also studied to evaluate the state of nonframework aluminum in the zeolitic pore. The micropore volumes W₀(N₂) of the dealuminated zeolites calculated by the D-R plot of the adsorption isotherms of nitrogen hardly depended upon the degree of dealumination, indicating that the dealuminated zeolites maintain their framework structure. However, the micropore volumes W₀(N₂) from the adsorption isotherms of water vapor depended on the dealumination condition. In the case of the zeolites dealuminated by mild steaming or thermal treatment, the micropore volumes W₀(N₂) were consistent with those of untreated zeolites with the same concentration of framework aluminums. In the case of zeolites dealuminated by severe steaming, however, the micropore volumes W₀(N₂) were smaller than those expected from the concentration of framework aluminums. This suggests that the nonframework aluminum species released completely from the zeolite framework suppress strongly the adsorption of water molecules into the zeolitic pores.

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Alumina or zirconia pillared fluorotetrasilicic mica and montmorillonite were used as catalysts for the alkylation of naphthalene with t-butyl alcohol, and their catalytic activity and selectivity for the formation of 2, 6-di-t-butylnaphthalene were studied. In comparison with silica-alumina and HY zeolite, the pillared clays gave high yield of di-t-butylnaphthalenes. Selectivity for the formation of 2, 6-di-t-butylnaphthalene is correlated well with selectivity for adsorption of 2, 6-di-t-butylnaphthalene, indicating that selective formation of 2, 6-isomer may be attributed to molecular sieving effect of pillared clays.

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Various barium phosphates were prepared at 98 (± 1) °C by the homogeneous precipitation method using mixed solutions of BaCl₂, NaH₂PO₄ and urea (Ba²⁺/P mole ratio =1.00∼1.67), and investigated with respect to the effect of reaction conditions on the formation of various barium phosphates and the composition of barium apatite (Ba-Ap).
The barium hydrogenphosphate was o btained as the initial product in all of reaction conditions. Bariurn hydrogenphosphate was transformed to Ba-Ap by aging in concentrated solutions of Ba²⁺ ions, but the transformation was difficult in dilute solutions of Ba²⁺ ions. The barium carbonate once formed during the precipitation reaction remained in the product after the aging. Lowering the concentration of urea was preferred for the synthesis of various barium phosphates without BaCO₃. The single phase of BaHPO₄ was obtained by heating solutions with low Ba²⁺/P mixing ratios for a little while. On the othe r hand, both lowering the concentration of urea and heightening the Ba²⁺ /P mixing ratios, the single phase of Ba-Ap was obtained by heating solutions with low concentrations of urea and high Ba²⁺/P mixing ratios for a long time.
The incorporation of Cl^- ions or CO₃^2- ions into the crystal of Ba-Ap obtained was unavoidable. The incorporation of these ions, however, could be decreased by lowering the concentrations of urea and Cl^-ions and heightening the concentration of Ba²⁺ ions in the initial solution.
Consequently, it was clarified that the formation of various barium phosphates and the composition of Ba-Ap were influenced by various factors: concentrations of Ba²⁺ ions, Cl^- ions, urea or heating time, etc. The single phase of BaHPO₄, Ba-Ap or BaCO₃ could be obtained by the control of these factors.

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In order to clarify the influence of interlayer cation species and layer charge upon formation and properties of titania pillared fluorine micas, synthetic expandable fluorine micas having different interlayer cations, such as Li⁺, Na⁺, K⁺, and layer charges [M_xMg_3-xLi_xSi₄O₁₀F₂(M=Li, Na, K, x=0.4, 0.5, 0.6, 0.8)] were reacted with titania sol prepared by hydrolyzing titanium tetraisopropoxide (TTIP)with hydrochloric acid. Based on specific surface area measurements for pillared micas, the most appropriate reaction conditions of complex formation were decided to be [TTIP/HC1] ratio of 4, concentration of HCl used being 1 mol/dm³ with reaction time of 180 min. Interlayer cation species of host micas had the profound influence on complex formation, resulting in different titania contents and surface areas of pillared micas in the order of K⁺±Na⁺ ± Li⁺. This is due to the difference in expandability of host micas since interlayer cation determines swelling characteristics and intercalation process. In addition, layer charge had also the influence on titania contents and surface areas of pillared micas. Especially, Na_x-system was greatly influenced by layer charge, giving a maximum of titania content at x_??_0.6. Such an appearance of the maximum can be explained in terms of the decrease in swelling ability and the increase in cation exchange capacity with increasing layer charge. Thermal durability of titania pillared fluorine micas depended on titania content, being about 500 °C for Li_x-system having maximum titania content. Part of interlayer titania was expelled from interlayer region onto crystal surface of mica to precipitate as anatase at higher temperatures.

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A new highly effective preconcentration method for Cu (II), Ni(II), Co (II) and Cd ( ) in water samples which involved the collection of rubeanic acid complexes of these metal ions on a micro-membrane filter (MMF, cellulose nitrate, diameter: 4 mm, pore size: 0.20 μm) was developed. It was possibleto determine metal ions concentrated on a surface of the MMF by GFAAS in which the MMF was introduced directly into a cup-type graphite cuvette. More than 95% of Cu (II), Co (II), and Cd (II) were recovered by adding a salting out reagent (NaCl) and/or a coprecipitant (excess Cu (II)). For the MMF direct ashing technique on the GFAAS, an addition of 20 Ml of 5 vol% H2SO4/DMF was effective to reduce the variation of results. Only 5 ml of each samples of sub-ppb level of Cu (II), Ni (II), Co (II) and Cd (II) was enough for one analysis. The detection limits (3 × σ of blank solution) for Cu(II), Ni(II), Co (II) and Cd(II) are 80, 95, 50 and 1.6 ppt, respectively. An application of the method for the determ ination of Cu (II), Ni(II) and Cd (II) in river water was also described.

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Determination and distribution of 18 elements such as rare earth elements (REE), uranium and thorium in apatite minerals were examined using inductively coupled plasma-mass spectrometry. The sample solution (1 mg/ml) which were prepared with hot concentrated nitric acid were directly injected into the plasma. REE, uranium and thorium contents in the apatite were determined by a calibration curve method. However, the intensity of thorium decreased by calcium phosphate in macro-component. Therefore, thorium was separated from these calcium phosphate by solvent extraction with 0.1 mol/dm³ 3-Phenyl-4-benzoyl-5-isoxazolone-DIBK system. DIBK phase was evaporated by heating, dried and ashed with concentrated nitric and perchloric acids. After allowing cooling, 0.1 mol/dm³ nitric acids was added to dissolve any precipitate. The REE, uranium and thorium content in apatite minerals from USA, China and Jordan were found to be (0.24-172), (9.69-111), (0.7-7.95) ppm, respectively. It was found that lanthanoid in apatite minerals following the Oddo and Harkins law.

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To control the quality of fuel gas, a suitable analyzer is required for continuous determination of its total sulfur content. In my previous work, the analyzer equipped with dual-flame photometric detector (D-FPD) has been developed. The main purpose in this study is to determine continuously the total sulfur content in various types of fuel gas using D-FPD analyzer. The working curves of 3 types of fuel gas for total sulfur content were made out with gases contained tetrahydrothiophene in the range from 38mg/m³ to 103 mg/m³. The total sulfur contents in fuel gases were determined by FPD-GC and D-FPD analyzers, respectively. It is evident that there is good agreement between these results. It seems that the D-FPD analyzer can be used in the determination of total sulfur content in various types of fuel gas.

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The reaction of azulene (1) with a 0.4- 0.5 molar amounts of a heterocyclic aldehyde (i.e., furaldehyde, thiophene-2-carbaldehyde, pyrrole-2-carbaldehyde and imidazole-2-carbaldehyde) in acetic acid at room temperature (25 °C) for 1-8 h under argon gave the corresponding 1, 1'-methylenediazulene having a heterocyclic substituent at C-a position (2, 23.0% yield; 3, 49.8%; 4, 2.3%; 5, 70.6%, respectively). The structures of these products were established on the basis of their spectro scopic (UV/VIS, ¹H-NMR and EI-MS) data.

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Methacryloyl-terminated urethane prepolymers were prepared from 2, 4-diisocyanatotoluene and poly (oxypropylene) triol (PPT, Fig.1) with various molecular weights, and terminated with 2-hydroxyethyl methacrylate. The prepolymers may be cured by UV-radiation to give poly (urethane-methacrylate)membranes. The hard segment concentration and crosslinking density had a pronounced effect on the characteristics such as dynamic mechanical property and oxygen permeability of the membranes.

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The alumina thin films were prepared by the sol-gel method using aluminium nitrate dissolved in 1, 3butanediol solution. The thin films usually had a homogeneous and flat surface structure. However, the surface structure of the films obtained after the immersion in an ethylene glycol and water mixed solution at 100°C changed to the sponge-like surface texture which was composed of fibrillar particle. The Al/Si intensity ratio of the thin films on a glass substrate measured by XRFS increased with the concentration of an ethylene glycol in immersion solution and reached to an approximately constant value above 22 mol%. The crystal structure of alumina after immersion changed into the amorphous from boehmite with an increase in ethylene glycol concentration. The addition of ethylene glycol has an effect upon the growth of the fibrillar particle which composes thin films. Therefore, ethylene glycol in the immersion solution restrains the peptisation of alumina particle and the production of boehmite by the hydration and enhances the growth of fibrillar particle. It was found that the vacant size in the thin films could be controlled by the ethylene glycol concentration in the immersion solution.

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