We examined the “micelle-vesicle transition” through the mixing effect of single–tailed thiol surfactants produced by the cleavage of gemini surfactants, [C₁₂H₂₅N(CH₃)₂CH₂CH₂SSCH₂CH₂N(CH₃)₂C₁₂H₂₅] 2Cl (C₁₂SSC₁₂), which have a disulfide bond in the spacer chain. Phase diagrams of C₁₂H₂₅N(CH₃)₂CH₂CH₂SHCl-didodecyldimethylammonium chloride (-DDAC) and C₁₂SSC₁₂-DDAC were determined by conductivity and pyrene fluorescence probe methods. The aggregate diameters were evaluated by dynamic light scattering (DLS). The critical vesicle concentration (CVC) was confirmed by the abrupt increase in the intensity of light scattering with excitation at 335 nm. Vesicle formation was confined to the DDAC-rich region of the C₁₂SSC₁₂-DDAC system, while the vesicle formation region for the -DDAC system spread out with the addition of dithiothreitol (DTT) to C₁₂SSC₁₂-DDAC. This implies that single–tailed surfactants can induce a more favorable environment for molecular packing of the vesicular surface. The micelle-vesicle transition occurs with disulfide spacer chain cleavage of gemini surfactants at a particular specific concentration range.

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1. By exhaustive photooxidation of rat liver ornithine δ-aminotransferase [EC 2.6.1.13] in the presence of methylene blue, the 22 histidine residues in the native enzyme was decreased to 16 and, the groups was decreased to 10 in the photooxidized holo-and apo-enzymes. The inactivation by photooxidation was partially prevented by the presence of α-ketoglutarate but not by ornithine. The semilogarithmic plot of the inactivation was biphasic, indicating two groups involved in this process (the rate constants were 0.5 and 0.12 min^-1, respectively).
2. In the native holo-enzyme, 4 SH groups reacted slowly with 5, 5'-dithiobis-(2-nitrobenzoic acid)(DTNB). The blocking of the first 2 SH groups did not change the enzyme activity, but that of the next 2 SH groups brought about 50% inactivation (the rate constant, 0.011 min^-1). In the presence of 4M guanidine, groups were immediately titrated with DTNB. In the native apoenzyme, by contrast, 10 SH groups were very rapidly titrated with DTNB and three groups were recognized with respect to the rate of reaction with DTNB (the rate constants were 0.50, 0.046, and 0.010 respectively). The blocking of the first 2 SH groups in the apoenzyme brought about simultaneous inactivation to 20% of the control in both enzymatic overall and half reactions. The additions of substrates, ornithine, and α-ketoglutarate, to the apoenzyme showed no effects on the rate of reaction with DTNB.
3. Evidence for a difference in conformation between the holo-and apo-enzymes was obtained by a quantitative micro-complement fixation method. The decrease of antigenic activity in the complement fixation reaction observed with the apoenzyme was recovered to the level of the holo-enzyme by the addition of pyridoxal phosphate. The fact that the apoenzyme treated with 2 equimolar amounts of DTNB was able to bind pyridoxal phosphate was also presented.
4. M odifications of tyrosine, serine, and tryptophan residues were attempted with N-acetylimidazole, diisopropyl fluorophosphate, and 2-hydroxy-5-nitrobenzyl bromide, respectively. Amino groups of the holo-enzyme were modified with acetic anhydride. These modifications did not, however, result in inactivation.

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症例は66歳，男性．主訴は腹部腫瘤．腹部CTにて腹腔内腫瘤を指摘され外科紹介となった．触診にて右悸肋部に約12cm大の圧痛を伴う腫瘍抵抗を触知．血液検査では著明な炎症所見，貧血および低栄養状態が認められた．腹部CTにて，右上腹部に14×9cm大の腫瘤が上行結腸および横行結腸に接して，壁外に突出するかたちで認められ，GISTや悪性リンパ腫が疑われた．大腸ファイバーでは，横行結腸右側に隆起性病変が認められた．同部位の生検にて中分化腺癌を認め，壁外発育型大腸癌と診断し，手術を施行した．腫瘍は横行結腸から発生し，腸間膜側へ壁外性に発育．回腸の一部にも浸潤し一塊となっていたため，回腸部分切除を伴う右半結腸切除術を施行した．切除標本にて腫瘍内を貫き回腸へと通じる瘻孔を認めた．組織学的には乳頭状腺癌，pSI（ileum），pN0（0/），0，sP0，cLM1，fStageIVであった．

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Tri(ethylene glycol) terminated short alkylchain thiols (TEGCnSHs) offer good potential for constructing ultra-thin protein-resistant monolayers because they have an alkylchain for forming a densely packed monolayer and a flexible-hydrophilic oligo ethylene glycol arm for avoiding non-specific adsorption. Hybrid monolayers consisting of TEGCnSH and a maltoside ligand (MalC, for capturing lectin) were effective in detecting concanavalin A (Con A). This hybrid monolayer was more suitable for Con A detection than that modified with 100% ligands in terms of the detection limit and time. The anti-fouling properties, packing densities, interaction and homogeneity of TEGCnSH monolayers were confirmed in detail by surface plasmon resonance (SPR) measurements and electrochemical methods. SPR measurements revealed their excellent repellency to proteins and peptides of various sizes (M_W 400 − 104000). The electrochemical results indicated that the lower defects in the TEGCnSH monolayers suppressed the permeation of small peptides. The stability, homogeneity and packing density of the TEGCnSH monolayers were gradually improved as their alkylchain length increased.

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症例は60歳，女性．近医にてMRI上，子宮肉腫を疑われ，精査中に上行結腸腫瘍を指摘された．結腸切除，および子宮全摘術目的に入院．2004年10月に手術施行された．上行結腸中央部に後腹膜に一部強く浸潤する腫瘍を認め，結腸右半切除，後腹膜合併切除をおこなった．子宮肉腫と思われた腫瘍は後腹膜に存在し腹膜に覆われ，周囲に腫瘍血管の造生を認め，子宮と一部癒着していたものの，子宮との連続性はない腫瘍であった．総合所見は結腸腫瘍は中分化管状腺癌でA，circ，2型，70×60mm，pSE，pN2（8/），0，sP0，pM1，fStageIVであり，後腹膜腫瘍は平滑筋腫で子宮原発のparasitic leiomyomaの可能性が高く，一部に腺癌の転移を伴っているとされた．術後12カ月目に原病死した．Parasitic leiomyomaは比較的稀な疾患であり，これに大腸癌が転移した例はわれわれが検索しえた限り報告がなく，文献的考察を加え報告する．

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Monomeric thiol surfactants, [C_nH_2n+1N(CH₃)₂CH₂CH₂SH]Br, were produced by the cleavage of gemini surfactant containing a disulfide bond in the spacer chain, [C_nH_2n+1N(CH₃)₂CH₂CH₂SSCH₂CH₂N(CH₃)₂C_nH_2n+1]2Br. The disulfide bond was completely reduced by the addition of four times moles of dithiothreitol in water at room temperature. The critical micelle concentrations of monomeric surfactants were significantly increased in comparison with original gemini surfactants. The monomeric thiol surfactants were stable in the presence of dithiothreitol, whereas they returned gradually to their original gemini surfactants within several days due to air oxidation in water without dithiothreitol. The micelle formation induced by the disulfide linkage formation was suggested by the fluorescence intensity ratio of pyrene. The time course of decrease in thiol concentration associated with the recovery of gemini surfactants was confirmed by the absorption spectra utilizing the reactions with 4,4’-dithiopyridine.

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Thioester surfactants, [C₁₂H₂₅N(CH₃)₂(CH₂)_mSCOCH₃] Br (C₁₂mSAc, m = 4, 11, 12), yielded thiol surfactants via thiol-thioester exchange upon addition of dithiothreitol in aqueous solution. The thiolthioester exchange reaction was enhanced in a micellar system owing to the concentration effect. The enhanced aggregation upon deprotection of the thioacetate group was observed by dynamic light scattering measurements. The thiol surfactants yielded disulfide-linked gemini surfactants upon air oxidation and incubation with hydrogen peroxide. In contrast, the thiol surfactants yielded thioester double-tailed products by esterolytic reactions with p-nitrophenyl hexanoate. The introduction of an alkyl chain to the second side chain significantly decreased the critical micelle concentration and induced the micellar growth.

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Disulfide linked gemini surfactant having a long spacer chain, [C₁₀H₂₁N(CH₃)₂(CH₂)₁₁SS(CH₂)₁₁N(CH₃)₂C₁₀H₂₁]2Br (2C₁₀11SS), was prepared by the hydrolysis and oxidation process of thioester group for [C₁₀H₂₁N(CH₃)₂(CH₂)₁₁SCOCH₃]Br. The critical vesicle concentrations of double tailed surfactants such as dialkyldimethylammonium bromide were observed by the conductivity and light scattering methods. The disulfide bonds of gemini surfactant, [C₁₂H₂₅N(CH₃)₂CH₂CH₂SSCH₂CH₂N(CH₃)₂C₁₂H₂₅]2Br (2C₁₂SS), were rapidly cleaved by the addition of water-soluble dithiothreitol. However, it took long time to cleave the disulfide bonds of so-called double tailed surfactants 2C₁₀11SS due to vesicle formation. The dynamic light scattering method showed that the diameters of 2C₁₂SS micelles were increased with the cleavage of disulfide bonds, whereas those of 2C₁₀11SS aggregates remained almost constant at 17.6 ±1.3 nm in similar size with dialkyldimethylammonium bromide vesicles. The time course of disulfide cleavage was examined by the conductivity and HPLC analysis. The produced thiol surfactants were returned to their original gemini surfactants by the addition of H₂O₂.

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In order to investigate the formation process of self-assembled monolayers (SAM) of alkanethiol, we analyzed the molecular organization by Fourier-transform infrared reflection-absorption spectroscopy (FT-IR-RAS). The spectra suggested that molecular structure of the SAM on gold (111) surface is dependent on the immersion time. Alkanethiol in the SAM aligns normal to the substrat surface. A stable SAM embedded a close packed monolayer by the van der Waals interaction among alkanethiol and surface force from the gold substrate.

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Thiol self-assembly super-thin films have attracted considerable attention for molecular-level surface design as in chemical sensors, molecule-based devices and corrosion resistant films. Meanwhile, chromate coatings on zinc coated steel sheets are widely used as an economical method of preventing corrosion. In response to recent environmental regulations, such as the RoHS Directive, chromate-free coatings have been developed and applied to electrical appliances. However, a thinner coating is required to obtain better electroconductivity, which influences the electromagnetic shielding performance of digital electrical appliances. In this study, we investigated the corrosion resistance and film structure of alkanethiol and triazinethiol self-assembly super thin layers on zinc coated steel sheets. The corrosion inhibition mechanism of the thiol layers was discussed in order to develop a new design concept for thinner chromate-free coatings with high corrosion resistance. The alkanethiol layers showed high water repellency and poor corrosion resistance, and the triazinethiol layers with three thiol groups per molecule showed relatively poor water repellency and excellent corrosion resistance despite the very small thickness (several monolayers), as a result of suppressed oxygen reduction reaction determined by electrochemical measurement. XPS analysis revealed that alkanethiol molecules adhered to the zinc and formed layers with no decomposition, and triazinethiol molecules adhered to the zinc and then partially decomposed and reorganized to form a new network structure.

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A large plasmid in a virulent Shigella boydii 5 strain was transferred to plasmid-cured avirulent strains of S. boydii 5, S. boydii 12, S. sonnei form II, and Escherichia coli K12. The transconjugants acquired the ability to invade tissue culture cells, which indicated that the large plasmid in S. boydii is responsible for epithelial cell invasiveness.

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Thiol self-assembly super thin films have attracted attention from the viewpoint of surface design, e.g. chemical sensors, molecular devices and corrosion preventive films at a molecular level. On the other hand, chromate coatings on zinc coated steel sheets have been widely applied as an economical method of corrosion prevention. In response to recent environmental regulation, e.g., RoHS Directives, chromate-free coatings have been developed and applied to electrical appliances. However, a thinner chromate-free coating is required for the purpose of obtaining a better electro-conductivity, which influences the electromagnetic shielding performance of digital electrical appliances. In this paper, the corrosion resistance and film structure of alkane- and triazine- thiol self-assembly super thin layers on zinc coated steel sheets were investigated. The mechanism of corrosion prevention by the thiol layers was discussed in order to obtain a new design concept of thinner chromate-free coatings with high corrosion resistance. The alkanethiol layers showed high water-repellency and poor corrosion resistance, and the triazinethiol layers with three thiol groups per molecular showed relatively poor water-repellency and excellent corrosion resistance in spite of very small thickness such as a few monolayer thickness, which result from suppressing oxygen reduction reaction according to electrochemical measurement. It was found from XPS analysis that alkanethiol molecules combined to Zn form layers without decomposition, and triazinethiol molecules combined to Zn and the part of these molecules decomposed to form a new network structure.

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　こガセット継手に生じる疲労き裂の応急補修対策および疲労き裂の発生を抑制するための応力改善対策について，大型の梁試験体を用いて検討した．ストップホール，ストップホールの高力ボルトによる締め付けおよび添接板補修をそれぞれ対策方 法とし，疲労き裂が発生した箇所に用いて，その効果を確認した．また，ガセット継手の疲労き裂の発生の抑制を目的として，当て板補強による応力改善についても検討した．疲労き裂の補修対策としては，疲労き裂先端にストップホールを明け，その孔を用いて添接板補修を行う対策が最も効果があること，ガセット継手部の当て板による応力改善では，応力集中部に高力ボルトが配置されることにより，応力の低減効果が上がることが確認された．

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The competence of glycine-spheroplasts for transfection was investigated using singlestranded DNA of bacteriophage φA. During growth in nutrient broth supplementedwith 3% glycine, O.4% MgSO₄ and 5 to 15% sucrose, cells of E. coli develop sensitivity to the viral DNA, as well as to T4 particles (π) obtained by disruption withurea. The patterns of competence developed vary with the strain and physiologicalconditions, but the level of competence of glycine-spheroplasts is as high as that oflysozyme [EC 3. 2. 1. 17]-EDTA-spheroplasts. However, glycine-spheroplasts are lesssensitive to lytic agents and are less fragile osmotically than lysozyme-EDTA-spheroplasts. Some properties of the system for assay of infectious DNA are described.

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著者らはこれまでに、任意の運転条件におけるエアコンのCOP・消費電力の推定を行うための「家庭用エアコンの熱源特性モデル」の開発を行ってきた。 本報では、負荷が経時的に変動する状況下におけるエアコンの消費電力を適切に算出するために、既開発モデルに利用条件に応じてエアコンが処理する熱量を決定する機能を追加した「総合モデル」を開発する。

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