Search

斜面に存在する岩塊を安定化させるために用いられるロープネット工に関する維持管理の課題を解決するため，現地調査，素線のめっき量調査および腐食ロープの引張試験を実施した。現地調査の結果，ロープネット工には，さびによる腐食が発生しやすく，それらはワイヤーロープが立木や地表面に接している箇所に発生しやすいことがわかった。素線のめっき量調査結果から，良好な山林環境におけるワイヤーロープ部材の耐用年数は100年以上期待できることがわかった。また，腐食ロープの引張試験結果から，ワイヤーロープの寿命曲線を提案し，腐食しやすい箇所は施工後20年程度でワイヤーロープの部材を交換しなければならないことがわかった。以上のことからロープネット工施設は，適切な維持管理により腐食部材を順次交換することにより，30年程度と考えられていた施設の耐用年数を大幅に延ばすことが可能である。

本論文は，携帯GPS装置を用いた落石予防施設の模擬点検結果から，落石予防施設の効率的な維持点検手法を提案するものである。模擬点検は，全10箇所のロープネット工施設を対象に実施し，施設の位置情報として地形図のみを与えたA班と，地形図に加えGPS座標情報を与えたB班の2班を用意し，現場到達時間を比較した。この結果，B班の合計時間がA班と比較して42%短くなり，GPS座標情報によって維持点検作業を効率的に実施可能であることがわかった。施設の位置情報としてGPS座標情報等を盛り込んだGISを構築することにより，点検データの一元管理，最新の地形図利用，アクセスルート等の情報共有が可能となる。また，今後の点検計画の立案が容易になるなど施設の維持管理を効率的に行うことが可能となる。

Dewpoint corrosion by sulphuric acid has often been observed in the heat exchangers of coal-burning plants. If ashes contain active carbon, corrosion becomes particularly serious. Various nickel-base alloys with high corrosion resistance in such environments have been designed. The corrosion behaviour of these alloys was examined in hot concentrated sulphuric acid with and without active carbon. The corrosion resistance of ternary NiCiMo alloys in the acids without active carbon increases with increasing alloy molybdenum content. When active carbon is added to the acids, the corrosion rate increases significantly. This is due to acceleration of transpassive dissolution of molybdenum as a result of enhancement of cathodic activity with the addition of active carbon. The corrosion resistance in the acids with active carbon is enhanced by an increase in alloy chromium content, which improves the passivity in the acids.

A pyrimidine base specific and most basic alkaline RNase named RNase BL4 was isolated from bovine liver as a protein showing a single band on slab gel-electrophoresis. The enzyme is most active at pH 7.5. The enzyme was immunologically distinguishable from the known bovine RNases such as pancreatic RNase (RNase A), seminal RNase, kidney non-secretory RNase (RNase K2), and brain RNase (RNase BRb). The primary structure of this pyrimidine base-specific RNase was determined to be less than EDRMYQRFLRQHVDPDETG- GNDSYCNLMMQRRKMTSHQCKRFNTFIHEDLWNIRSICSTTNIQCKNGQMNCHEGVVRV- TDCRETGSSRAPNCRYRAKASTRRVVIACEGNPEVPVHFDK. It consists of 119 amino acid residues, and is 5 amino acid residues shorter than RNase A. The sequence homology of RNase BL4 with RNase A is 46.2%, and optimal alignment of RNase A and RNase BL4 requires five deletions, one at the 24th position, two at the 75th and 76th positions, and two at the C-terminus in RNase BL4. The RNase BL4 was highly homologous with a porcine liver RNase (RNase PL3, 94.1% homology) studied by Hofsteenge et al. (personal communication from Hofsteenge, J., Matthies, R., and Stones, S.R.).

DDT, an organochlorine pesticide, has been cited as a representative chemical suspected of having endocrine disrupting effects. In this study, the potential endocrine disrupting activities of p,p'-DDT, a major component of DDT, were investigated in rats in a 2-generation reproduction toxicity study in accordance with the most current test guidelines of the Ministry of Agriculture, Forestry and Fisheries in Japan, Organization for Economic Cooperation and Development (OECD) and United States Environmental Protection Agency (USEPA) with some modifications and additions. p,p'-DDT was given to parental rats at dietary levels of 0, 5, 50 or 350 ppm. Systemic toxicities in the parental animals consisted of tremors and subsequent deaths (females only) and/or pathological alterations of the liver (both sexes of animals) of the 2 higher dose groups. Reproductive and postnatal developmental toxicities were not evident up to the highest dose level except for the decreased pup viability index on postnatal day 21 in the 350 ppm group. Changes in serum estradiol and progesterone levels and/or a delay in male sexual maturation were noted in the 2 higher dose groups in a dose-dependent fashion, suggesting alterations of endogenous endocrine functions. However, these changes never resulted in substantial reproductive disorders.

Lens luxation was found in a male CD-1 (ICR) mouse. Ophthalmologic examinations revealed conical cornea anterior synechia and corneal neovascularization in the right eye. The lens was dislocated heterocentrically within the posterior chamber. Histologically, anterior lens luxation and adhesion between the iris and cornea were observed.

In order to investigate the nature of the amino acid residues involved in the active site of a ribonuclease from Rhizopus sp. (RNase Rh), carboxymethylation of RNase Rh with iodoacetate was performed. RNase Rh was found to be inactivated markedly at pH 3-5 by iodoacetate. From the pH profile of the rate of inactivation of RNase Rh, it was suggested that functional groups having pKa values of ca. 7.3 and 4.3 might be involved in this inactivation reaction. The determination of the amino acid composition of RNase Rh inactivated by iodoacetate at pH 5.0 indicated that the formation of about one residue of N3-carboxymethylhistidine was responsible for the loss of enzymatic activity. The results were very similar to those for an RNase from Asp. saitoi having very similar base specificity. The carboxymethylation of RNase Rh was inhibited by competitive inhibitors. Thus, the histidine residue modified might be involved in the active site of the enzyme.

The primary structure of a pyrimidine base-specific ribonuclease from bovine brain was determined. The sequence determined is (sequence; see text). Although the sequence homology of this RNase with bovine pancreatic RNase A is 78.2%, it consists of 140 amino acid residues, and it is 16 amino acid residues longer than RNase A at the carboxyl-terminal. In addition to an N-glycosylated long carbohydrate chain, the bovine brain RNase has two short O-glycosylated carbohydrate chains at the 129th and the 133rd serine residues. The additional C-terminal tail of the bovine brain RNase has a unique composition: 6 proline, 5 hydrophobic amino acids, and two basic amino acids, arginine and histidine.

To determine the distribution of a kidney acid RNase (RNase K2) and other RNases, the levels of RNase K2, RNase A, and seminal RNase (RNase Vs1) in bovine tissues and body fluids were measured by enzyme immunoassay. The crude extracts of several tissues and body fluids were fractionated by phospho-cellulose column chromatography. The enzymatic activities at pH 7.5 and 6.0 and enzyme contents of each tube were measured by enzyme assay and enzyme immunoassay, respectively. In the pancreas, parotid gland, and heart, most RNase activity was due to a single peak of RNase A, but a small amount of RNase K2 was always observed. In the kidney, there was about 5 times as much RNase K2 as RNase A. In the lung, although RNase K2 and RNase A were the major components, there are another two alkaline RNase peaks. In the spleen and liver, there are four RNases, two acid RNases, one of which is RNase K2, and two alkaline RNases including RNase A. A new acid RNase (non RNase K2-acid RNase) from both organs was immunologically the same. In serum, there are at least four RNases. By partial purification of serum RNases by phosphocellulose and heparin-Sepharose column chromatographies, at least 4 RNases, RNase A, RNase K2 and the other two alkaline RNases, one of which is immunologically indistinguishable from liver alkaline RNase, were confirmed. The other serum alkaline RNase was immunologically related to lung and spleen alkaline RNases. In conclusion, in bovine tissues and body fluids there are at least 7 types of pyrimidine-base-specific RNases: brain RNase, seminal RNase, RNase A, RNase K2, an acid RNase (RNase BSP1), an alkaline RNase (RNase BL4), and another alkaline RNase in serum.

Ionene polymers characterized by the alternating structure of ionene and crystalline poly(ethylene oxide) (PEO) segments were prepared as a function of PEO segment size. A microstructure of these ionenes and their 7,7,8,8-tetracyanoquinodimethane (TCNQ) salts were investigated with x-ray diffraction patterns, thermal scanning behavior, and polarizing micrographs. On the basis of this microstructure, the change in resistivity with temperature was studied. In Arrhenius' plots of the resistivity the simple salts in which the spherulites consisting of the PEO segments were observed showed a sharp decrease in resistivity with a rise in temperature [critical temperature resistor (CTR)] at about the melting point of the PEO segments, whereas the other simple salts in which the spherulites were not observed showed linear temperature dependence. The switching properties were confirmed similarly in repetitive heating/cooling cycles. This CTR characteristic was attributed to an increase in continuity in the conduction paths by melting spherulites. The apparent switching properties were not observed in the complex salts.

The elastomeric ionene polymers characterized by the alternating structure of the rigid polycation segments that contained 4,4′-bipyridilium rings and the flexible polypropyleneoxide (PPO) segments were prepared as a function of chain length of the PPO segments. From the measurements of dynamic mechanical properties and x-ray diffraction patterns of these ionenes and their 7,7,8,8-tetracyanoquinodimethane (TCNQ) salts, a microheterogeneous structure of the PPO segments and the polycation-TCNQ salts segments in the TCNQ salts was estimated. On the basis of this microstructure a change in the conductive and dielectric properties with an increase on the weight fraction of the PPO segments the TCNQ salts (Wf) were discussed. For the simple salts the values of resistivity (ρ) and activation energy of conduction (Ea) were increased with the increase in the value of Wf. The values of ρ for the complex salts also increased with the increase in the value of Wf, whereas the values of Ea were nearly constant (ca. 0.07 eV) until the value of Wf reached 0.8. Strong interaction between and TCNQ° molecules facilitated the formation of the continuous conduction columns and did not change their structure and properties. Dielectric constant (e) of the TCNQ salts attained 102−104. The dielectric behavior was consistent with the conductive behavior, and the appearance of the high e values was caused by polarization of carrier electrons of the TCNQ salts in the conductive paths isolated or interrupted by the PPO segments. As the Wf value increased, the e values of the TCNQ salts decreased. The decrease in the number of these paths accompanied by the increase in the Wf value led to reduced e values.

Elastomeric ionene–TCNQ salts with favorable electrical, mechanical, and processing characteristics were drawn mechanically. The electrical conductivity parallel and perpendicular to the drawing axis was investigated. Correlation between anisotropic conductivity and the change in microstructure was discussed. The resistivity ρ at 25°C of the simple salt (EI-TCNQ0) and the complex salt (EI-TCNQ0.5) were on the order of 105 and 102 Ω cm, respectively. In the drawn TCNQ salts, the ρ parallel to the drawing axis increased greatly; on the other hand, the ρ perpendicular to this axis increased slightly or was similar to the ρ of the undrawn TCNQ salts. The anisotropy in the ρ of EI-TCNQ0.5 between the two directions reached 40 times. The activation energy also increased in the direction parallel to the drawing axis. In the undrawn TCNQ salts, the continuous conduction paths exist isotropically. With drawing, the continuous conduction paths, particularly in the direction parallel to the drawing axis, break or make a structural change. The anisotropic conductivity disappeared with time in EI-TCNQ0; however, it was present in EI-TCNQ0.5 even after 200 days under ambient conditions.

The dynamic mechanical, thermal scanning, stress-strain and water sorption behaviours of the elastomeric ionene consisting of ionene and poly(propylene oxide) (PPO) segments are studied. The effect of PPO segment size on the microphase-separated structure in this material is described by the change of dynamic mechanical and thermal relaxation temperatures. The mixing of the PPO segment into the ionene segment domain increases with decrease of PPO segment size and reduces the crosslinking effect of the ionene segment domain, which leads to an increase in hysteresis for loading in this material. The number of equilibrium sorbed water molecules per ionene segment increases with increase in the purity of the ionene segment domain.

The primary structure of a non-secretory ribonuclease from bovine kidney (RNase K2) was determined. The sequence determined was VPKGLTKARWFEIQHIQPRLLQCNKAMSGV NNYTQHCKPENTFLHNVFQDVTAVCDMPNIICKNGRHNCHQSPKPVNLTQCNFIAGRYPDC RYHDDAQYKFFIVACDPPQKTDPPYHLVPVHLDKYF. The sequence homology with human non-secretory RNase, bovine pancreatic RNase, and human secretory RNase are 46, 34.6, and 32.3%, respectively. The bovine kidney RNase has two inserted sequences, a tripeptide at the N-terminus and a heptapeptide between the 113th and 114th position of bovine pancreatic RNase; on the other hand, it is deleted of the hexapeptide consisting of the 17th to the 22nd amino acid residue of RNase A. The amino acid residues assumed to be the constituents of the bovine pancreatic RNase active site are all conserved except F120 (L in RNase K2).

Computed tomography of the liver was performed on two patients with subacute hepatitis. The CT findings included the presence of multiple regenerative nodules in the atrophied liver, shown by decreased CT attenuation. Complications due to hepatitis, such as massive ascites and splenomegaly, were also observed. The CT observations during the course of the disease suggested that the hepatic necrosis had been repaired by hypertrophy of regenerating nodules, not by an increase in the number of nodules, which ultimately gave rise to postnecrotic cirrhosis. Scintigraphy confirmed atrophy and repair of the liver. Thus, CT and scintigraphy were considered to be useful for the diagnosis of extensive hepatic necrosis and for evaluating the process of liver repair.

The carboxyl group in a ribonuclease from Rhizopus sp. (RNase Rh) was modified by a water-soluble carbodiimide, 1-cyclohexyl-3-(2-morpholinyl-(4)-ethyl)carbodiimide p-toluenesulfonate (CMC). From the relation between the extent of modification and the enzymatic activity, it was concluded that at least the modification of two carboxyl groups seemed to induce the loss in enzymatic activity. In the presence of 1 M cytidine, RNase Rh activity was protected from the CMC-modification. Under conditions in which the enzyme was inactivated to 20% activity, about 70% of the enzymatic activity was retained in the presence of cytidine. The inactivation of the RNase Rh pre-treated with CMC in the presence of cytidine with [14C]CMC indicated that the RNase Rh lost its enzymatic activity with the incorporation of about one [14C]CMC. Therefore, it could be concluded that one carboxyl group is involved in the active site of RNase Rh. The binding of the CMC-modified RNase Rh with 2'-AMP was studied spectrophotometrically. The affinity of the modified RNase Rh towards 2'-AMP decreased markedly upon CMC modification.

In order to clarify the reason for the variation in specific activities of ribonuclease preparations from Rhizopus sp. ribonuclease (RNase Rh), low specific activity species (RNase Rh') were separated from native RNase Rh by DEAE Toyopearl 650 column chromatography and characterized. When RNase Rh' was subjected to gel electrophoresis in the absence of 2- mercaptoethanol, it gave a 24 kilodalton (kDa) protein band, but in the presence of the reducing agent it gave 17 and 7 kDa bands. These two peptides were separated by gel filtration and their NH2-terminal amino acid sequences were determined. The results indicated that RNase Rh' was an enzyme species cleaved at about the 50th residue of native RNase Rh by proteases during the course of purification, but the two fragments were still covalently joined by S-S bridges. RNase Rh' retained about 70% of the native activity and has a similar conformation to the native enzyme.

Two acid RNases were purified from bovine spleen by means of ammonium sulfate fractionation, chromatographies on-phospho-cellulose, heparin-Sepharose CL-6B, poly G-Sepharose, and 2', 5'-ADP-Sepharose, and gel filtration on Toyopearl HW 55F. Both purified preparations were homogeneous as judged by disc electrophoresis at pH 4.3. They were designated as RNase BSP1 and RNase BSP2 in the order of elution from a phospho-cellulose column. RNase BSP2 was immunologically indistinguishable from RNase K2 from bovine kidney. RNase BSP1 was a typical pyrimidine base-specific, uridylic acid-preferential RNase and had very sharp pH optimum at 6.5. RNase BSP1 thus obtained was a glycoprotein giving two major bands on SDS-slap electrophoresis. Although the apparent molecular weight of RNase BSP1 was distributed in the range of 27,000-20,000, it decreased to about 17,000-18,000 after endoglycosidase F digestion. The N-terminal amino acid sequence up to the 20th amino acid had no homology to those of RNase K2 and RNase A.

Two RNases (RNases K1 and K2) were purified from bovine kidney by means of column chromatography on phospho-cellulose, Sephadex G-50, CM-cellulose, heparin-Sepharose, nd agarose-APUP. They were named RNase K1 and RNase K2 in order of elution from the heparin-Sepharose column. The purity of RNase K1 thus obtained was about 90% by SDS-disc electrophoresis. RNase K2 was purified to homogeneity by SDS- and pH 4.3 disc electrophoresis. The yield of RNase K2 was 3.4 mg from 11 kg of kidneys. The antigenic properties of the two bovine renal RNases were studied by Ouchterlony's double diffusion analysis. RNase K1 and RNase A were serologically indistinguishable. RNase K2 did not cross-react immunologically with RNase K1 or RNase A. The molecular weights of these RNases determined by gel-filtration on Sephadex G-50 were 13,400 and 14,600 for RNase K1 and RNase K2, respectively. The pH optima for RNase K1 and RNase K2 were 8.5 and 6.5, respectively. Both RNase K1 and RNase K2 were as acid stable as RNase A. RNase K2 was less heat-stable than RNase K1 and RNase A. Although both renal RNases were pyrimidine nucleotide-specific enzymes, RNase K1 and RNase A were more preferential or cytidylic acid than RNase K2. The chemical composition of RNase K2 was determined. RNase K2, like human urinary RNase Us, contained one tryptophan residue. The N-terminal sequences of RNase K2 and RNase Us were determined by Edman degradation. Rnase K2 had a homologous sequence of about 10 amino acid residues with the sequence of RNase Us, a typical non-secretory RNase, within the N-terminal 30 residues.