Effect of Extrusion on the Critical Current Density of Bi1.4Pb0.6Sr2Ca2Cu3Ox Superconducting Wires

The effect of extrusion on improving the critical current density ( J _c) of Bi_1.4Pb_0.6Sr₂Ca₂Cu₃O _x superconducting wires is investigated. Calcined powders (Bi_1.4Pb_0.6Sr₂Ca₂Cu₃O _x ) are first mixed with a forming aid—a thermoplastic polymer (polyethylene)—for workability, and then extruded, using a capillary rheometer, to form wires 2 mm in diameter. The J _c value, measured by the four-probe method in liquid nitrogen at 77 K, is improved substantially by the following process: (1) the superconducting precursors are extruded at high viscosity with a forming aid, to align the platelike particles unidirectionally; (2) the forming aid alone is carefully burned out, without destroying the extruded configuration; and (3) the extruded wires are annealed at 850°C in air for more than 96 h.     

High thermal expansion KAlSiO4 ceramic

Orthorhombic kalsilite (KAlSiO₄) was prepared by solid-state reaction from K₂CO₃, Al₂O₃, and SiO₂. The axial thermal expansion coefficients of the orthorhombic kalsilite were 1.6×10^–5°C^–1 for the a-axis, 1.6×10^–5°C^–1 for the b-axis, 2.8×10^–5°C^–1 for the c-axis, and 2.0×10^–5°C^–1 for the average from room temperature to 1000°C. A high thermal expansion ceramic consisting of the orthorhombic kalsilite was prepared by sintering. The densification was promoted by adding Li₂CO₃. The KAlSiO₄ ceramic sintered at 1200°C for 2 h with 5 wt% Li₂CO₃ had a bending strength of 65 MPa and linear thermal expansion coefficient of 2.2×10^–5 °C^–1 from room temperature to 600°C.     

Thermal and mechanical properties of sintered machinable LaPO4-ZrO2 composites

Monazite-type LaPO₄ was synthesized using the wet precipitation and mechanochemical reaction methods. Mixtures of xLaPO₄-(1−x)ZrO₂ (x=0-1) were dry-pressed to disks or plates and cold isostatically pressed (CIP) at 100 MPa for 10 min and then sintered at temperature between 1500 and 1600°C for 1, 3, and 5 h in air, respectively. Relative densities larger than 96.8% (x≤0.4) and 92% (x=0.5-1) were achieved. It was found that these composites with x≥0.25 and single-phase LaPO₄ were machinable, that is, they could be cut and drilled using conventional tungsten carbide metal-working tools. The drilling rates were measured by applying a fixed load of 49 N to the drill at 6400 rpm. X-ray diffraction results showed that the LaPO₄ did not react with ZrO₂, at least at 1600°C in air. The linear thermal expansion coefficient, thermal conductivity, bending strength, and Young’s modulus of the sintered composites were measured.     

Effect of carbon tetrachloride-induced hepatic injury on stereoselective N-demethylation of chlorpheniramine by rat hepatic cytochrome P450 2C11 isozyme

We examined the effect of a carbon tetrachloride (CCl4)-induced hepatic injury on the stereoselective N-demethylation of RS-(+/-)-chlorpheniramine (Chp) by cytochrome P450 (CYP) 2C11 isozyme. In the non-treated rat liver microsomes, the stereoselective N-demethylation of racemic Chp was observed. However, in the CCl4-treated (0.5 ml/kg, i.p.) rat liver microsomes, the N-demethylation activities of S-(+)- and R-(-)-Chp decreased continuously up to the third day after the treatment with CCl4, and reached about 9 and 13% of control values, respectively, and the stereoselective N-demethylation of Chp was not observed. Moreover, in the liver microsomes at the 7th day after the treatment with CCl4, the N-demethylation activities of both enantiomers recovered to an original level, and the stereoselective N-demethylation of Chp was again observed. The addition of 30 microliters of the anti-rat CYP2C11 serum to the reaction mixture containing 1 mg of microsomal protein inhibited the formation of monodesmethylchlorpheniramine (DMChp) from both enantiomers to 74 and 57% of the control values for S-(+)- and R-(-)-Chp, respectively. In the liver microsomes of a male rat at the 1st day after the treatment of CCl4, the addition of the anti-rat CYP 2C11 serum (30 microliters) also caused 25% inhibition of the formation of DMChp from S-(+)-Chp, but anti-rat CYP2C11 had no inhibitory effect on the rates of microsomal N-demethylation of R-(-)-enantiomer. On the other hand, in the liver microsomes of a male rat at the 7th day after the treatment with CCl4, the anti-rat CYP2C11 serum had an inhibitory effect on the rates of microsomal N-demethylation of either S-(+)- or R-(-)-enantiomers again. Moreover, it was confirmed by Western blotting analysis that the density of the stained bands of CYP2C11 in the liver microsomes from male rats at the 1st, 2nd and 3rd days after the treatment with CCl4, was thinner than that from non-treatment male rats. These results indicated that the changes of N-demethylation activities of Chp in the CCl4-induced hepatic injury were due to the variation of microsomal CYP2C11.     

Mechanochemical Changes of Weinschenkite-Type RPO4·2H2O (R = Dy, Y, Er, or Yb) by Grinding and Thermal Reactions of the Ground Specimens

It is reported that, on mechanochemical treatment, weinschenkite-type RPO₄·2H₂O (R = Dy, Y, or Er) gradually transforms into rhabdophane-type RPO₄· nH₂O (n = 0.5 to 1) and weinschenkite-type YbPO₄·2H₂O into xenotime-type YbPO₄, at room temperature in air. Rhabdophane-type YPO₄·0.8H₂O and ErPO₄·0.9H₂O obtained by grinding weinschenkite-type RPO₄·2H₂O (R=Y or Er) are new. The new rhabdophane-type YPO₄·0.8H₂O and ErPO₄·0.9H₂O gradually transform to xenotime-type YPO₄ and ErPO₄ when heated above 900°C (R = Y) and 700°C (R = Er) in air.     

Preparation of Cubic Perovskites A(B2/5W3/5)O3 (A=Ba or Sr, B=Na or Li)

Pure cubic perovskites Ba(Na_2/5W_3/5)O₃, Sr(Na_2/5W_3/5)l5)O₃, and Sr(Li_2/5W_3/5)O₃ were prepared by solid-state reaction at 600° to 650°C in air, by starting with oxides or carbonates of the various elements. The cubic forms have an ordered arrangement of the B cations in the ABO₃ structure, and the lattice constants are a =0.8324 nm [Ba(Na_2/5W_3/5)O₃], 0.8136 nm Sr(Na_2/5W_3/5)O₃], and 0.7958 nm [Sr(Li_2/5W_3/5)O₃]     

An analysis of semantic structure of KAITEKI-KAN and development of its measuring method using emotional words

Conspicuous facial pores are one of the more serious aesthetic defects of concern to most women. However, the mechanism that causes the conspicuousness of facial pores remains unclear. We observed the epidermal structure around the conspicuous pores on cheeks in vivo using a confocal microscope in detail, and found that there were peculiar epidermal structures around the conspicuous facial pores. These epidermal structures were characterized by a thick epidermis, which reached the deep dermis, and elongated dermal papillae. As the shape and the size of these epidermal structures at more than one hundred micrometers below the surface were similar to those of the surface hollow area around the conspicuous pores, we thought that this epidermal structure was one cause for facial pore conspicuousness on cheeks. To improve these epidermal structures through contraction of keratinocytes, we developed l-isostearylglycerol-3-phosphate, which promoted the gel contractile ability of keratinocytes and suppressed the keratinocytes' growth in vitro. The treatment of lotion containing l-isostearylglycerol-3-phosphate could alter the epidermal structures and decrease the hollow area around the conspicuous facial pores.
Key words:  pores, conspicuousness, hollow, epidermis, structure, dermal papillae, keratinocytes, contraction, follicle, cheek.     

Comparative studies on activities of antimicrobial agents against causative organisms isolated from urinary tract infections (1993). I. Susceptibility distribution

The frequencies of isolation and susceptibilities to antimicrobial agents were investigated on 657 bacterial strains isolated from patients with urinary tract infections in 10 hospitals during the period of June 1993 to May 1994. Of the above total bacterial isolates, Gram-positive bacteria accounted for 28.3% and a majority of them were Enterococcus faecalis. Gram-negative bacteria accounted for 71.7% and most of them were Escherichia coli. 1. Enterococcus faecalis Ampicillin (ABPC), imipenem (IPM) and vancomycin (VCM) showed the highest activities against E. faecalis isolated from patients with urinary tract infections. The MIC90s of them were 2 micrograms/ml. Piperacillin (PIPC) was also active with the MIC90 of 8 micrograms/ml. The others were not so active with the MIC90s of 32 micrograms/ml or above. 2. Staphylococcus aureus including MRSA VCM showed the highest activities against S. aureus isolated from patients with urinary tract infections. Its MIC90 was 1 microgram/ml. Arbekacin (ABK) was also active with the MIC90 of 2 micrograms/ml. The others were not so active with the MIC90s of 32 micrograms/ml or above. 3. Staphylococcus epidermidis VCM showed the strongest activity against S. epidermidis isolated from patients with urinary tract infections. Its MIC90 was 1 microgram/ml. ABK was also active with the MIC90 of 4 micrograms/ml. The others except ABPC were not so active with the MIC90s of 32 micrograms/ml or above. 4. Streptococcus agalactiae Most of the agents were active against S. agalactiae isolated from patients with urinary tract infections. Penicillins, cephems, erythromycin (EM), and clindamycin (CLDM) showed the highest activities. The MIC90s of them were 0.25 microgram/ml or below. Amikacin (AMK) and minocycline (MINO) showed somewhat low activities with the MIC90s of 16 micrograms/ml. 5. Citrobacter freundii IPM showed the highest activities against C. freundii isolated from patients with urinary tract infections. Its MIC90 was 2 micrograms/ml. Cefozopran (CZOP) and gentamicin (GM) were also active with the MIC90s of 8 micrograms/ml. Penicillins and cephems generally were not so active. 6. Enterobacter cloacae IPM and GM showed the highest activities against E. cloacae. The MIC90s of them were 1 microgram/ml. CZOP and tosufloxacin (TFLX) were also active with the MIC90s of 8 micrograms/ml. Penicillins and cephems except CZOP showed lower activities with the MIC90s of 64 micrograms/ml or above. 7. Escherichia coli Most of antimicrobial agents were active against E. coli. Flomoxef (FMOX), CZOP, IPM, CPFX and TFLX showed the highest activities against E. coli. The MIC90s of them were 0.125 microgram/ml or below. Cefmenoxime (CMX), ceftazidime (CAZ), cefuzonam (CZON), latamoxef (LMOX), carumonam (CRMN), norfloxacin (NFLX) and ofloxacin (OFLX) were also active with the MIC90s of 0.25 microgram/ml. Penicillins and MINO were not so active with the MIC90s of 32 micrograms/ml or above. 8. Klebsiella pneumoniae CZOP, IPM and CRMN showed the highest activities against K. pneumoniae. The MIC90s of them were 0.125 microgram/ml or below. CAZ, CZON, CFIX, CPFX and TFLX were also active the MIC90s of 0.25 microgram/ml. Penicillins were not so active with the MIC90s of 128 micrograms/ml or above. 9. Proteus mirabilis P. mirabilis was susceptible to a majority of drugs. CMX, CAZ, CZON, LMOX, CFIX, CRMN and CPFX showed the highest activities against P. mirabilis isolated from patients with urinary tract infections. The MIC90s of them were 0.125 microgram/ml or below. MINO was not so active with the MIC90 of 256 micrograms/ml or above. 10. Pseudomonas aeruginosa Most of the agents were not so active against P. aeruginosa. IPM showed MIC90 of 8 micrograms/ml.     

Atomic force microscopic studies on the structure of bovine femoral cortical bone at the collagen fibril-mineral level

The structure of cortical bone at the collagen-mineral level was investigated by means of atomic force microscopy. Surfaces of the specimens treated with collagenase and ethylenediaminetetraacetic acid (EDTA) were examined. Images of blob-like objects observed in intact specimen became clearly outlined after collagenase treatment; the sizes of the blob decreased, suggesting that each blob had been fragmented by the collagenase treatment. Following EDTA treatment of an intact specimen, an image of thread-like objects appeared; the thread was partly constructed by trains of blobs and the other parts of the threads had a periodic pattern along its longer axis. The period was almost equal to the collagen D-period of the Hodge–Petruska model, indicating that the threads are collagen fibrils and that the blobs are related to the mineral phase in bone. It was concluded that minerals were deposited on and along collagen fibrils. A decorated collagen fibril model for the spatial relationship between mineral and collagen fibril was proposed. According to our model, the mineral inside the collagen fibril is about one forth of the extrafibrillar mineral.     

Elongational flow studies of hinged rodlike molecules

Poly(amino acid) in an intermediate state of its helix-coil transition is known to be in a hinged rodlike conformation. In this work, the responses of poly(amino acids) in the hinged rodlike conformation against an elongational flow field were investigated by monitoring their flow-induced birefringence. Poly(L-glutamic acids) (PGA) and poly(γ-benzyl-L-glutamate) (PBLG) were examined as polyelectrolyte and noncharged poly(amino acids), respectively, and the results were compared. In the plots of flow-induced birefringence, Δn, against strain rate, $ {\dot \varepsilon } $, for hinged rodlike PBLG, there was a critical strain rate, $ \dot \varepsilon_0 $, below which Δn was not observed. Over $ \dot \varepsilon_0 $, the birefringence pattern observed was identical with that of rodlike molecules. The Δn vs. $ {\dot \varepsilon } $ plot for hinged rodlike PGA had characteristics of a rigid rod at any strain rate and there was no $ \dot \varepsilon_0$ observed. The rotational diffusion coefficient, D_r, of PBLG in the hinged rodlike conformation was larger than that for its helical conformation, while D_r, for the hinged-rodlike PGA was smaller than that for its helical conformation. It is concluded that the hinged-rodlike PGA molecule is in an extended form and that the hinged-rodlike PBLG is hydrodynamically more compact and rigid than that in its quiescent state. It is deduced that at $\dot \varepsilon_0$ hinged rodlike PBLG molecules collapse to a conformation optically anisotropic and mechanically rigid. © 1996 John Wiley & Sons, Inc.