Microstructure and Magnetic Properties of (Co-Fe)-Al-O Thin Films

(Co-Fe)-Al-O soft magnetic thin films were fabricated by cosputtering Co-Fe alloy and Al₂O₃ ceramic targets using an inductively coupled RF (radio frequency) sputtering system. The microstructure and magnetic properties of various (Co-Fe)/(Al-O) thin-film compositions were systematically characterized. A specimen with the composition (Co₇₂Fe₁₇Al₁₁)-O exhibited excellent high-frequency magnetic properties, with a value >300 for the real part of the permeability and >2 GHz for the self-resonant frequency. High-resolution transmission electron images revealed nanometer-order Al₂O₃ amorphous phases separating the Co-Fe alloy nanograins. The excellent high-frequency magnetic properties were derived from the particular microstructure of these thin films.     

The hydroxyl radical scavenger Nicaraven inhibits glutamate release after spinal injury in rats

Neuronal degeneration after trauma is mediated in part by release of excitatory amino acids (EAAs) and oxygen free radicals (OFR). We evaluated the effect of i.v. treatment with a hydroxyl radical scavenger ((+/-)-N,N'-propylenedinicotinamide; AVS) and spinal hypothermia (33 degrees C) on spinal CSF glutamate release after spinal trauma. In a control group, spinal compression evoked at 10 min a significant increase (5-fold) in glutamate which declined over 4 h (2.1-fold). AVS treatment attenuated glutamate release but had no additive effect. These data suggest that this compound can be effective in modulating spinal excitotoxicity resulting from increased OFR synthesis and corresponding potentiation of EAA release.     

Current status of acute respiratory infections in children under five years of age in Nairobi, Kenya

Two hundreds and twenty-six children under five years of age with pneumonia were recruited from an urban poor area in Nairobi, Kenya, and examined for pathogens for 1 year from February 1997. One hundred and twenty-eight of the 226 patients were pathogen-positive cases. The patients under 1-year-old were 61.8% of the pathogen-positive cases. A total 192 organisms were isolated from 128 pathogen-positive patients. Streptococcus pneumoniae had the highest prevalence rate of 31.3%, followed by respiratory syncytial virus with 10.4%, Candida albicans with 9.9%, Moraxella (B) catarrhalis with 7.8%. In S. pneumoniae, 66.7% of the organism was resistant to oxacillin. It was also shown that 51.1% and 65.1% of the S. pneumoniae strains were resistant to gentamicin and trimethoprim/sulfam, respectively. From these results, it is clear that a lot of multi-drug resistant S. pneumoniae strains including penicillin-resistant S. pneumoniae were frequently detected in an urban poor area.     

Occurrence of an organochlorine synergist S-421 in fish and shellfish

S-421 is a synergist for pyrethroid and organophosphorus pesticides, and is widely used in termiticides or commercial household insecticides. S-421 is mutagenic, stable and ubiquitous in the environment, and has been detected in household dust, surface water, sediments and rain-water. Here we describe the concentration of S-421 residues in domestic and imported fish collected in Osaka. S-421 was extracted with acetone/hexane, purified through silica gel 40 and quantified by ECD-GC. S-421 was detected in 36 out of 44 samples of domestic fish and shellfish analyzed, at a level of < 0.2 to 2.3 ng/g (mean: 0.6 ng/g), and in 27 out of 43 imported samples at a level of < 0.2 to 1.0 ng/g (mean: 0.2 ng/g). The levels of S-421 detected in fish were lower than those of DDTs and almost the same as those of HCHs. More attention should be paid to the behavior in the environment of S-421, as well as other persistent organochlorine pollutants, such as HCHs, DDTs and chlordane.     

Effects of humic substances on the pattern of oxidation products of pentachlorophenol induced by a biomimetic catalytic system using tetra(p-sulfophenyl)porphineiron(III) and KHSO5

In the presence of humic substances (HSs), the oxidative conversion of pentachlorophenol (PCP) was found to be efficiently catalyzed by tetra(p-sulfophenyl)porphineiron(III) (Fe(III)-TPPS) using KHSO5 as an oxygen donor. Ortho-tetrachloroquinone (o-TeCQ), 2-hydroxyl-nonachlorodiphenyl ether (2H-NCDE), 4-hydroxyl-nonachlorodiphenyl ether (4H-NCDE), and octachlorodibenzo-p-dioxin (OCDD) were identified as the major byproducts of the reaction. Decreased amounts of these byproducts were produced in the presence of HS. In particular, the addition of HSs with a lower degree of humification resulted in a large decrease in the formation of dimers, such as 2H-NCDE, 4H-NCDE, and OCDD. More than 60% of the chlorine, which was released from PCP, was found in the HS fractions after the reaction. This suggests that chlorinated intermediates from PCP were incorporated into the HS. Pyrolysis-GC/MS and 13C NMR studies confirmed that the binding of the chlorinated intermediates was covalent in nature and that the intermediates were copolymerized with HS via oxidative coupling reactions. A Microtox test demonstrated that the toxicity of the HS fraction containing PCP-derived intermediates was much lower than that of the mixture of PCP and HS in the absence of a catalytic reaction.     

Examination of sex-hormonal activity of some additives for PVDC film

Stabilizers (epoxidized linseed oil and epoxidized soybean oil) and plasticizers (acetyl tributyl citrate, diacetyl monolauryl glyceride and dibutyl sebacate) commonly used in polyvinylidene chloride (PVDC) films and extracts of such films were investigated for estrogenic and androgenic activity by means of estrogen receptor (ER) and androgen receptor (AR) competitive ligand-binding assays. Further, in in vivo experiments, ovariectomized Sprague-Dawley rats were observed for uterine wet weight change, uterine endometrium hyperplasia and vaginal mucosa cornification, following administration of each test compound or extract orally (0.5 or 500 mg/kg) or subcutaneously (0.5 or 100 mg/kg). No significant response or change was observed with any of the test compounds or extracts, either in vitro or in vivo. The results thus indicate that neither the stabilizers and plasticizers used in PVDC films, nor their extracts, exert sex-hormonal activity.     

A new type of beta-N-Acetylglucosaminidase from hydrogen-producing Clostridium paraputrificum M-21

A beta-N-acetylglucosaminidase gene (nag84A) was cloned from Clostridium paraputrificum M-21 in Escherichia coli. The nag84A gene consists of an open reading frame of 4647 by encoding 1549 amino acids, with a deduced molecular weight of 174,311, which have a catalytic domain belonging to family 84 of the glycoside hydrolases. Nag84A was purified from a recombinant E. coli and characterized. Although Nag84A exhibited high homology to the hyaluronidase from Clostridium perfringens, it did not degrade hyluronic acid. The enzyme hydrolyzed chitooligomers such as di-, tri-, tetra-, penta- and hexa-N-acetylchitohexaose, and synthetic substrates such as 4-methylumbelliferyl N-acetyl beta-D-glucosaminide [4-MU-(G1cNAc)], but did not hydrolyze 4-MU-beta-D-glucoside, 4-MU-alpha-D-glycoside, 4-MU-alpha-D-GlcNAc, 4-MU-alpha-D-galactoside, 4-MU-beta-D-xyloside, PNP-beta-D-galactoside, and PNP-alpha-D-xyloside. The enzyme was optimally active at 50 degrees C and pH 6.5, and the apparent K(m) and V(max) values for 4-MU-(GlcNAc) were 8.5 microM and 1.39 micromol/min/mg of protein, respectively. SDS-PAGE, zymogram, and immunological analyses suggested that Nag84A was inducible by ball-milled chitin. Since Nag84A has a high molecular weight with a family 84 catalytic domain with high homology to hyaluronidases but no hyaluronidase activity, the enzyme is a novel beta-N-acetylglucosaminidase different from others reported having low molecular weights and belonging to family 3 and family 18.     

Isolation and characterization of Bacillus sp. INT005 accumulating polyhydroxyalkanoate (PHA) from gas field soil

A gram-positive bacterium (designated strain INT005) that accumulated polyhydroxyalkanoate (PHA) was isolated from gas field soil. From its morphological and physiological properties and the partial nucleotide sequence (about 500 bp) of its 16S rDNA, it was suggested that strain INT005 was similar to several species of the genus Bacillus. We confirmed that strain INT005 is a Bacillus sp. The PHA productivities of strain INT005 were higher than those of Bacillus megaterium and Ralstonia eutropha at 37-45 degrees C reported to date, and it was suggested that the PHA synthase of INT005 may exhibit moderate thermostability. The bacterium had the ability to produce poly(3-hydroxybutyrate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate), poly(3-hydroxybutyrate-co-4-hydroxybutyrate-co-3-hydroxyhexanoate), and poly(3-hydroxybutyrate-co-6-hydroxyhexanoate-co-3-hydroxyhexanoate) from the appropriate carbon sources. The PHA synthase from INT005 showed similar substrate specificity to those of class I and III PHA synthases and strain INT005 produced PHAs with various monomer compositions. From the analysis of monomer composition and PHA accumulation in the presence of acrylic acid, it was suggested that de novo fatty acid synthesis and beta-oxidation are involved in the PHA synthesis of Bacillus sp. INT005. Since Bacillus sp. INT005 could synthesize PHA even at 45 degrees C and PHAs with various monomer compositions, and only one report on the cloning of the synthesis-related genes from a Bacillus species (B. megaterium) has been published;Bacillus sp. INT005 is thought to be very valuable source of PHA synthesis-related genes.     

Obtaining Shape from Scanning Electron Microscope using Hopfield Neural Network

In the environment of the Scanning Electron Microscope (SEM), it is necessary to establish the technology of recovering the 3D shape of a target object from the observed 2D shading image. SEM has the function to rotate the object stand to some extent. This paper uses this principle and proposes a new method to recover the object shape using two shading images taken during the rotation. The proposed method uses the optimization of the energy function using Hopfield neural network, which is based on the standard regularization theory. It is also important to give the initial vector that is close to the true optimal solution vector. Computer simulation evaluates the essential ability of the proposed method. Further, the real experiments for the SEM images are also demonstrated and discussed.     

Directed self-assembly of Ge nanostructures on very high index, highly anisotropic Si(hkl) surfaces

Families of very high-index planes, such as those which bifurcate spontaneously to form a hill-and-valley structure composed of opposing facets, provide natural templates for the directed growth of position-controlled self-organized nanostructures with shapes determined by the facet width ratio R. For example, deposition of a few ML of Ge on Si(173 100 373), corresponding to R(113/517) = 1.7, results in a field of 40-nm-wide Ge nanowires along [72 187] with a uniform period of 60 nm.