Metal-containing initiator systems

Summary The polymerization of vinyl monomers with the initiator systems of ferrocene and acid anhydrides were investigated. The initiator activity for radical polymerization of methyl methacrylate (MMA) was higher than that for styrene (St). However, isobutyl vinyl ether was not polymerized. The rate of polymerization of MMA with ferrocene/benzoic anhydride system was in proportional to the square root concentrations of both compounds of the initiator system, indicating the mechanism of radical polymerization. When an alternating copolymer of ethylene with maleic anhydride was used as an acid anhydride, a graft copolymer, which was soluble in dimethylformamide and tetrahydrofuran, was produced from radical polymerization of MMA.     

Addition Reactions of Benzyne, Dienes, Dichlorocarbene, and Oxygen to C60

Benzyne was found to add to C₆₀ in good yield to give C₆₀(C₆H₄)_n (n=1-4). Typical Diels-Alder dienes were also found to add to C₆₀ under thermally mild conditions. Adducts of C₆₀ with 2,3-dimethylbutadiene, cyclopentadiene, hexa-chlorocyclopentadiene, 1,3-diphenylisobenzofuran, and anthracene were obtained. Further reactions of these products such as elimination and autooxidation reactions were investigated. Addition reaction of dichlorocarbene to C₆₀ gave C₆₁Cl₂. Oxidation of C₆₀ with m-chloroperbenzoic acid gave C₆₀O_n(n=1, 2). All of the products were isolated by means of HPLC and characterized by mass spectroscopy.     

Investigation of Coxiella burnetii contamination in commercial milk and PCR method for the detection of C. burnetii in egg

A total of 244 milk samples collected from supermarkets in Tokyo were examined for contamination with Coxiella burnetii. C. burnetii DNA was detected in 131 (53.7%) of the samples by nested PCR. PCR-positive samples were injected into immunosuppressed A/J strain mice. Of the 22 PCR-positive milk samples tested, none resulted in isolation of C. burnetii from the mice. Heat-treatment was sufficient to inactivate C. burnetii in commercial milk. In addition, a PCR detection method for C. burnetii in chicken egg was developed. Egg yolk was added to an equal volume of 1 mol/L of NaCl phosphate buffer and homogenized for removal of protein and lipid. After centrifugal separation, the supernatant was removed, and template DNA in the precipitate was extracted using SDS, proteinase K and NaI. Using such prepared samples, 3.2 x 10(1) C. burnetii particles in 1 g of egg yolk could be detected by nested PCR. All of 200 chicken egg samples collected from supermarkets in Tokyo were negative for C. burnetii by the nested PCR method.     

Isolation of novel bacteria and actinomycetes using soil-extract agar medium

Novel bacteria were discovered using an isolation technique consisting of (i) selection of microorganisms that grew on soil-extract agar medium, but not on conventional media, and (ii) detection of small microbial colonies with a microscope. Three bacterial strains thus isolated were provisionally designated Shinshu-th1, -th2, -th 3, and five actinomycete strains, Shinshu-MS-01, -02, -03, -04, -05, respectively. Sequence analysis of their 16S rDNA showed that th1 had 95--96% homology with three unculturable bacteria, and th2 had 96% similarity to Bradyrhizobium sp., one unculturable and one unidentified bacterial strain. A phylogenetic study indicated that both strains were alpha-Proteobacteria belonging to the order Rhizobiales and the family Bradyrhizobiaceae. Since they had low homology (96%) with their close relatives, it is possible that th1 and th2 belong to a new genus. The actinomycetes Shinshu-MS-02 and -03 had 95--96% homology with four strains of Actinomadura, -04 had 95--96% similarity to Streptosporangium and Microbispora, and -05 had 97--98% homology with three strains of Acrocarpospora, Herbidospora and Planotetraspora. According to the phylogenetic study, both 02 and 03 are possibly new species of Actinomadura, -04 of Streptosporangium, and -05 of Acrocarpospora. Shinshu-th 3 and -MS-01 were identified as Mycobacterium cookii and Frankia sp., respectively, having 99% homology with these species.     

Dilution effects on X-ray photoelectron spectra of La<Subscript>0.8</Subscript>Sr<Subscript>0.2</Subscript>MnO<Subscript>3</Subscript> with SiO<Subscript>2</Subscript>

Diluted samples of La_0.8Sr_0.2MnO₃ with SiO₂ were prepared by calcination of the MCM-41 molecular sieve soaked in precursor solutions with various concentrations (0.1, 0.05 and 0.005 mol/l). The diluted samples from the 0.1, 0.05 and 0.005 mol/l solutions showed ferromagnetic behavior in temperature dependent magnetic susceptibility below 300, 250 and 100 K, respectively. The electron binding energy of the La 3d_5/2 main peak of the diluted samples from the 0.1, 0.05 and 0.005 mol/l solutions were 835.7, 836.0 and 837.4 eV, respectively, and were larger than that of La_0.8Sr_0.2MnO₃ bulk sample (834.2 eV). Reduction in intensity of the La 3d charge-transfer satellite was more pronounced for more diluted sample. The Mn 2p_3/2 main peak of all the diluted samples remained at 642.2 eV, which is larger by 0.6 eV than that of the bulk sample (641.6 eV). The charge-transfer peak energy in the optical absorption spectra was the same (2.3 eV) for all the diluted samples, and the energy was larger by 0.4 eV than the bulk one (1.9 eV). The dilution caused localization of charge carriers within the La_0.8Sr_0.2MnO₃ lattices isolated by the insulator. Suppression of charge flow between the isolated La_0.8Sr_0.2MnO₃ lattices resulted in the enlargement of the La 3d electron binding energy and the decrease of the La 3d charge-transfer satellite peak intensity, and also the lowering of the ferromagnetic ordering temperature. © Springer Science + Business Media, Inc.     

Kinetic analysis of ion pair extraction of an alkyl sulfate anion across a liquid/liquid interface by fluorescence microspectroscopy and microelectrochemistry of single microdroplets

Mass transfer of an alkyl sulfate anion with a (ferrocenylmethyl)trimethylammonium cation from water into single oil microdroplets was kinetically studied by microcapillary injection, fluorescence microspectroscopy, and microelectrochemistry. The partitioning ratio and the extraction rate significantly depended on the alkyl chain length of the alkyl sulfate anion. The extraction rate for the n-dodecyl sulfate or n-tridecyl sulfate ion was proportional to both the alkyl sulfate ion and ferrocene derivative concentrations while that for the n-undecyl sulfate ion was proportional to the anion concentration alone. The results are discussed in terms of transfer of the individual ions across the microdroplet/water interface and adsorption/ion pair formation of the alkyl sulfate ion at the microdroplet/water interface.     

Characterization of fluoride fibers for the Optical Hawaiian Array for Nanoradian Astronomy project

We report on the interferometric characterization of a pair of 300 m long single-mode non-polarization-maintaining fibers designed for the Optical Hawaiian Array for Nanoradian Astronomy ('OHANA) project whose goal is to realize a kilometric near-infrared astronomical array by connecting the large telescopes of the Mauna Kea observatory with single-mode fibers. The fluoride glass fibers are operated in the astronomical K band (2.0-2.4 microm) in which their attenuation is low. We have measured very low differential chromatic dispersion, and the wideband fringe visibility is 0.9 if the two fiber arms have the same temperature. The thermal sensitivity of fibers with respect to their interferometric properties has been studied. The differential chromatic dispersion of the fibers is highly sensitive to the temperature difference. On the contrary, the coherent loss due to mismatch of polarization states is not significantly dependent on the temperature difference. Compensation of thermally induced differential dispersion by use of CaF2 glass plates is demonstrated.     

Development of a gas injection/specimen heating holder for use with transmission electron microscope

A new gas injection/specimen heating holder is developed for the purpose of in situ observation of gas reaction of materials at high temperatures in a transmission electron microscope at near-atomic resolution. A fine tungsten wire is employed as a heating element of the holder and a battery is used as the power source. Gas was injected onto specimens in the form of particles lying on the heating element via a nozzle. The maximum pressure near specimens was middle of 10(-2) Pa, while the pressure in the electron-gun chamber was kept to 2 x 10(-4) Pa. This gas injection/specimen heating holder was applied to observe solid-gas reactions. The reactions observed include oxidation of pure In into In2O3, reduction of SiO2 into Si and re-oxidation of Si into SiO2.