Active sites of Cu-ZSM-5 for the decomposition of acrylonitrile

The catalytic decomposition of acrylonitrile (AN) over Cu-ZSM-5 prepared with various Cu loadings was investigated. AN conversion, during which the nitrogen atoms in AN were mainly converted to N₂, increased as Cu loading increased. N₂ selectivities as high as 90–95% were attained. X-ray diffraction measurements (XRD) and temperature-programmed reduction by H₂ (H₂-TPR) showed the existence of bulk CuO in Cu-ZSM-5 with a Cu loading of 6.4 wt% and the existence of highly dispersed CuO in Cu-ZSM-5 with a Cu loading of 3.3 wt%. Electron spin resonance measurements revealed that Cu-ZSM-5 contains three forms of isolated Cu²⁺ ions (square-planar, square-pyramidal, and distorted square-pyramidal). The H₂-TPR results suggested that in Cu-ZSM-5 with a Cu loading of 2.9 wt% and below, Cu⁺ existed even after oxidizing pretreatment. The activity of AN decomposition over Cu/SiO₂ suggested that CuO could form N₂, but, independent of the CuO dispersion, nitrogen oxides (NO_x) were formed above 350 °C. Cu⁺ and the square-pyramidal and distorted square-pyramidal forms of Cu²⁺ showed low activity for AN decomposition. Temperature-programmed desorption of NH₃ suggested that N₂ formation from NH₃ proceeded on Cu²⁺, resulting in the formation of Cu⁺. The Cu⁺ ions were oxidized to Cu²⁺ at around 300 °C. Thus, high N₂ selectivity over Cu-ZSM-5 with a wide range of temperature was probably attained by the reaction over the square-planar Cu²⁺, which can be reversibly reduced and oxidized.     

Automatic extraction of citation information in Japanese patent applications

The need for academic researchers to retrieve patents and research papers is increasing, because applying for patents is now considered an important research activity. However, retrieving patents using keywords is a laborious task for researchers, because the terms used in patents for the purpose of enlarging the scope of the claims are generally more abstract than those used in research papers. Therefore, we have constructed a framework that facilitates patent retrieval for researchers, and have integrated research papers and patents by analysing the citation relationships between them. We obtained cited research papers in patents using two steps: (1) detection of sentences containing bibliographic information, and (2) extraction of bibliographic information from those sentences. To investigate the effectiveness of our method, we conducted two experiments. In the experiment involving Step 1, we prepared 42,073 sentences, among which a human subject manually identified 1,476 sentences containing citations of papers. For Step 2, we prepared 3,000 sentences, in which the titles, authors, and other bibliographic information were manually identified. We obtained a precision of 91.6%, and a recall of 86.9% in Step 1, and a precision of 86.2% and a recall of 85.1% in Step 2. Finally, we constructed an information retrieval system that provided two methods of retrieving research papers and patents. One method was retrieval by query, and another was from the citation relationships between research papers and patents.     

Determination of residual avoparcin in chicken muscle by HPLC with ultraviolet and amperometric detection

An analytical method was developed for determination of residual avoparcin in chicken muscle by measuring alpha- and beta-avoparcin, major components of the pharmaceutical preparation avoparcin, using HPLC with UV and amperometric detectors. The analytical HPLC was run on a Cosmosil 5C18-AR column (4.6 mm x 25 cm) with a gradient formed from A: 2.5% acetic acid, 0.01 mol/L sodium heptane sulfonic acid-acetonitrile (88.5:11.5) (pH 4.0) and B: 2.5% acetic acid-acetonitrile (10:90), using UV and amperometric detection (AMD) with glassy-carbon electrode (+900 mV). Avoparcin was extracted from chicken muscle by homogenization with methanol-0.2 mol/L sulfuric acid (6:4) followed by centrifugation after pH adjustment to 4 with 1 mol/L sodium hydroxide. The supernatant was evaporated to dryness, and the residue was dissolved in water. The aqueous layer was adjusted to pH 4 by adding 1 mol/L sodium hydroxide. Then it was purified on a Sep-Pak tC18 plus ENV cartridge. The cartridge was washed with water, and retained substances were eluted with 50% methanol. The eluate was evaporated to dryness under reduced pressure. The residue was dissolved in water and determined by HPLC. Recoveries of avoparcin spiked in chicken muscle were 73.1-88.1% at levels of 2-10 micrograms/g. The detection limits were 0.5 microgram/g (UV) and 0.2 microgram/g (AMD).     

High Resistance of Cu–Ferrierite to Coke Formation During NH3-SCR in the Presence of n-Decane

Selective catalytic reduction of NO _x by NH₃ over Cu–FER and Cu–ZSM-5 in the presence of n-decane and SO₂ was investigated. NO _x conversion over Cu–ZSM-5 decreased in the presence of n-decane, owing to inhibition of the active sites by coke formation. In contrast, coke formation was negligible over Cu–FER, which maintained its NO _x conversion activity even in the presence of decane. Coke formation was negligible over H–ZSM-5 and H–FER supports, which suggests that Cu species were involved in coke formation. Temperature-programmed reduction by H₂ and electron spin resonance spectroscopy indicated that [Cu–O–Cu]²⁺ was probably the Cu species involved in coke formation over Cu–ZSM-5.     

Dynamic MR hepatocholangiography with the SIP Fast GRE (saturation inversion projection fast gradient echo) method

The purpose of this study was to assess the utility of dynamic MR hepatocholangiography with the Gd-EOB-DTPA enhanced SIP Fast GRE sequence in the hepatobiliary system. The SIP Fast GRE sequence was used for sequential imaging of the hepatobiliary system with a frame rate of 3 sec in a 256 x 192 matrix. Dynamic sequential acquisition was performed for 51 min before and after the injection of 30 mu mol/kg of Gd-EOB-DTPA in a rabbit. Dynamic images of the hepatobiliary system were obtained in the rabbit study. Dynamic MR hepatocholangiography provides better functional information than conventional MR cholangiography.     

Establishment and characteristics of a practical and useful astrocyte cell line transformed by a temperature-sensitive mutant of simian virus 40

Treatment of primary cultured rat hepatocytes with hepatocyte growth factor (HGF) gives rise to inositol phosphate formation, cytosolic calcium oscillation, activation of mitogen-activated protein (MAP) kinase and phospholipase D (PLD), and arachidonic acid release, leading to DNA synthesis. Pretreatment of cultured hepatocytes with pertussis toxin (PT), which is known to adenosine diphosphate-ribosylate Gi and Go guanine nucleotide -binding proteins and to inhibit their functions, partially inhibited HGF-induced [3H]thymidine incorporation in a concentration-dependent manner. These results suggest that HGF-mediated DNA synthesis of hepatocytes is partly regulated via PT-sensitive guanine nucleotide-binding protein. Therefore, the effects of PT treatment on HGF-induced signal-transduction pathways were investigated. HGF-induced MAP kinase activation and arachidonic acid release were decreased by PT treatment, whereas PLD activation was diminished by PT to the level of unstimulated control. PT also interfered with HGF-induced inositol phosphate formation and cytosolic calcium oscillation. These results suggest that both PT-sensitive and PT-insensitive pathways are involved in HGF-induced signaling.     

Structure-activity relationships of protoberberines having antimicrobial activity

13-Alkyl derivatives (2-6 and 8-12) of berberine (1) and palmatine (7) were subjected to in vitro antibacterial activity tests against Bacillus subtilis and Salmonella enteritidis. Antibacterial activity increased as the length of the C-13 aliphatic side chain increased. The effects of the oxygen-substituents on aromatic rings A, C, and D of protoberberinium salts 13-20 on the antimicrobial activity against Staphylococcus aureus, B. subtilis, S. enteritidis, Escherichia coli, and Candida albicans are also discussed. The change in lipophilicity of the protoberberinium salts caused by modification of the substituents appears to influence the antibacterial activity. 13-Hexylberberine (6) and 13-hexylpalmatine (12) exhibited the greatest antibacterial activity.     

Effects of bioabsorbable and non-resorbable barrier membranes on bone augmentation in rabbit calvaria

The aim of this study was to compare the effects of bioabsorbable and non-resorbable membranes on experimental guided bone augmentation in 8 Japanese white rabbits. A cutaneous flap was demarcated and raised from the forehead of each animal, the periosteum was lifted, and the calvarial bone on both sides of the midline was exposed. A titanium screw was inserted into the bone on each side of the midline and one screw was covered with a bioabsorbable (polylactic acid) membrane and the other with a non-resorbable (expanded polytetrafluoroethylene) membrane. The implanted screws and membranes were then covered with the periosteum and cutaneous flap. After healing for 6 months, the animals were euthanized and the experimental area was prepared for histological investigation. New bone had formed under both membranes with no sign of infection or membrane exposure. The amount of newly generated bone (89.0 +/- 17.3% versus 54.7 +/- 14.0%, P <0.05) and the percentage of newly generated bone height (81.5 +/- 6.3% versus 58.9 +/- 7.8%, P <0.05) in the space beneath the non-resorbable membrane was greater than that beneath the bioabsorbable membrane. However, there were no statistically significant differences between the bioabsorbable and non-resorbable membranes with respect to the percentage areas of mineralized bone (52.3 +/- 11.3% versus 47.1 +/- 6.7%, P = 0.8658) and bone marrow (47.7 +/- 11.3% versus 52.9 +/- 6.7%, P = 0.4838) and bone contact with the screw (88.3 +/- 6.9% versus 89.2 +/- 7.3%, P = 0.9999). In conclusion, at least within the limitations of this rabbit model, we suggest that non-resorbable membranes with sufficient stiffness should be used to obtain greater bone volume and height instead of bioabsorbable membranes for the GBR procedure, and that this will facilitate predictable bone augmentation in spaces beyond the bone surface. Therefore, the bioabsorbable membrane could not replace the non-resorbable membrane used in this model.