Polymeric ultraviolet absorber

Polymeric fine powder, prepared by polymerization of glycidylmethacrylate–divinylbenzene, was reacted with 2,4-dihydroxylbenzophenone. The resultant polymer was effective as a polymeric ultraviolet absorber, and no migration was observed in polypropylene.     

Preparation and characterization of (Ba1−xSrx)TiO3 films by sol–gel processing

Barium strontium titanate ((Ba, Sr)TiO3) thin films were prepared on Pt/Ti/Si substrates by the sol–gel method using metal alkoxides. The dependence of the dielectric constant for the films on the film compositions and on the film thickness were investigated. The dielectric constant of the film of thickness 180 nm had the highest value of 230 at composition ratios of [Ba+Sr]/[Ti]=1.04 and [Sr]/[Ba+Sr]=0.6. The dielectric constant of the films with this composition decreased from 390 to 160 with a decrease in the film thickness from 440 to 100 nm. The decrease in the dielectric constant with increasing film thickness is attributed to the existence of a low-dielectric-constant interface layer adjacent to the electrodes. © 1998 Kluwer Academic Publishers     

The tinctorial stability of safflor yellow B under experimentally controlled model conditions

Several factors affecting the stability of safflor yellow B tincture were studied in experimentally scheduled model systems. Higher temperatures act on the colour more unfavourably than lower ones. UV light promotes bleaching of the pigment, pH is a decisive factor for preserving safflor yellow B, which deteriorated more rapidly under alkaline conditions. The pigment is sensitive to atmospheric O₂. Metal cations affect the stability of safflor yellow B: trivalent manganese and divalent iron reduce the orange-yellow colour most strikingly. The tinctorial stability and the practical utility of safflor yellow B are outlined on the basis of the experimental data.

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Die Farbstabilität von Safflor-Gelb B unter experimentell kontrollierten Modellkonditionen

Zusammenfassung In experimentell kontrollierten Modellsystemen wurden verschiedene Faktoren, die sich auf die Stabilität von Safflor-Gelb B auswirken, kontrolliert. Hohe Temperaturen und UV-Licht wirken bleichend. Das Pigment ist sehr pH-empfindlich, besonders im Alkalischen. Auch Sauerstoff zerstört es. Von den Metallionen wirken insbesondere Mn³⁺ und Fe²⁺ bleichend. Farbbeständigkeit und praktische Brauchbarkeit von Safflor-Gelb B werden diskutiert.

     

Fundamental and clinical evaluation of cefozopran in low birth weight infants and neonates

We conducted fundamental and clinical evaluations of a cephem antibiotic, cefozopran (SCE-2787, CZOP), in infants with low birth weights and mature infants. (1) Blood concentrations CZOP was intravenously given in bolus dose of 20 mg/kg to the newborn. The blood antibiotic concentrations were 69.7 micrograms/ml at 30 minutes after administration and the elimination half life was 2.99 hours in mature infants aged 1 to 3 days. They were 38.7 micrograms/ml and 2.85 hours in those aged 4 to 7 days, and 40.8 micrograms/ml and 3.81 hours in those aged 8 days or elder, respectively. In infants with lower birth weights aged 4 to 7 days the blood antibiotic concentrations were 48.6 micrograms/ml at 30 minutes after i.v. administration and the elimination half life was 3.77 hours. The blood antibiotic concentrations at 30 minutes after intravenous doses of 10, 20 and 50 mg/kg in mature infants aged 8 days or elder were 21.1, 40.8 and 153.6 micrograms/ml (value at 60 minutes) and the elimination half lives were 2.24, 3.81 and 3.07 hours, respectively. Administration of CZOP at doses of 20 and 40 mg/kg by intravenous drip infusion over 30 minutes gave the blood drug concentrations of 48.0 and 103.2 micrograms/ml at the end of the infusion and the half lives were 2.60 and 3.33 hours, respectively. (2) Urinary excretion The urinary excretion rates after i.v. bolus doses of 10, 20 and 40 mg/kg were 28.4 to 58.6% of dose. The urinary excretion rate after i.v. drip infusion of 40 mg/kg over 30 minutes was 49.0% of dose. (3) Transfer into cereblospinal fluid The transfer of the antibiotic into cereblospinal fluid in patients with serous meningitis was 4.1 to 15.5 micrograms/ml at 1 hours after administration. (4) Clinical results The clinical efficacy was judged "good" or "excellent" in 2 of the 3 patients with septicemia and in all of the 10 patients with suspected septicemia. It was judged "excellent" in all of the 9 patients with pneumonia, 3 with urinary tract infections and 3 with intrauterine infections. Prophylactic use of the antibiotic was effective in all of the 12 patients. Of the patients in whom bacteriological evaluation was successful, 7 of the 10 causative organisms were confirmed to be eradicated. No adverse drug reactions of signs and symptoms were recognized. Fourteen abnormal alterations of the laboratory test values such as elevation of gamma-GTP and that of GPT were recognized in 8 patients (16.7%). None of them were particularly serious. These results indicate that CZOP is a drug useful for treatment and prevention of infections in infants with lower birth weights as well as in mature infants.     

Homolog of a-factor receptor gene in Saccharomyces exiguus

Homologs of Saccharomyces cerevisiae STE3, a -factor receptor gene were detected from S. exiguus NFRI 3539 by low stringency Southern hybridization. This strain might have at least two types of homolog. One of these homologs, designated as e-STE3 was cloned. Its nucleotide sequence revealed 60% identity to STE3. The putative protein coding region consisted of 453 amino acid residues. The amino acid sequence identity between STE3 and e-STE3 was 62%, and that of the N-terminal 303 amino acid residues considered to be the pheromone binding domain was 79%. The e-STE3 sequence submitted to the DDBJ/EMBL/GenBank data libraries is available under Accession Number AB003086. © 1998 John Wiley & Sons, Ltd.     

Magnetovolume effects in manganese nitrides with antiperovskite structure

Magnetostructural correlations in antiperovskite manganese nitrides were investigated systematically for stoichiometric and solid solution Mn₃Cu_1?xA_xN (A = Co, Ni, Zn, Ga, Ge, Rh, Pd, Ag, In, Sn or Sb). This class of nitrides is attracting great attention because of their giant negative thermal expansion, which is achieved by doping Ge or Sn into the A site as a relaxant of the sharp volume contraction on heating (spontaneous volume magnetostriction ω_s) because of the magnetovolume effects. The physical background of large ω_s and mechanism of how the volume contraction becomes gradual with temperature are central concerns for the physics and applications of these nitrides. An entire dataset of thermal expansion, crystal structure and magnetization demonstrates that the cubic triangular antiferromagnetic state is crucial for large ω_s. The intimate relationship between ω_s and the magnetic structure is discussed in terms of geometrical frustration related to the Mn₆N octahedron and magnetic stress concept. The results presented herein also show that ω_s depends on the number of d electrons in the A atom, suggesting the important role of the d orbitals of the A atom. Not all the dopants in the A site, but the elements that disturb the cubic triangular antiferromagnetic state, are effective in broadening the volume change. This fact suggests that instability neighboring the phase boundary is related to the broadening. The relation between the gradual volume change and the local structure anomaly is suggested by recent microprobe studies.     

Deposition and structural analyses of molybdenum-disulfide (MoS2)–amorphous hydrogenated carbon (a-C:H) composite coatings

In this study we developed composite coatings consisting of amorphous hydrogenated carbon (a-C:H) and molybdenum-disulfide (MoS₂), and clarified their microstructure. In addition, we interpreted the tribological properties of the composite coatings in the viewpoint of a deposition-induced microstructural modification. The coatings were produced by the hybrid deposition technique of RF-generated methane and argon plasma and DC magnetron co-sputtering of MoS₂ target. The deposition parameter investigated in this study was methane flow rate. Structural analyses were performed using a transmission electron microscope (TEM) and an atomic force microscope (AFM). Friction tests were conducted using a ball-on-disk type tribometer. From an electron micrograph, it was confirmed that nano-clusters were embedded into an amorphous carbon host matrix. Surface roughness of the composite coating was ～ 0.25 nm in R_a compared to 5.0 nm in R_a of sputtered MoS₂. The concentration measurements were performed, and the results show that the sulfur and molybdenum concentration ratio, [S]/[Mo], is ～ 0.9, which indicates that the amount of sulfur was reduced due to the discharged plasma. In friction tests, composite coatings showed high friction in a vacuum condition. It was considered that lubricant MoS₂ lamellar structures showing super-low friction in a vacuum condition during friction could not be formed between ball and coating during friction because of the lack of sulfur in embedded clusters.