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1.
Kakimoto Y Naetoko Y Hara H Miyatake M Sato A Tatsuguchi H Takahata R Yamamoto R Joh T 《Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan》2004,45(3):165-174
A collaborative study involving 8 laboratories was conducted to evaluate a method for the simultaneous determination of pesticide residues in 6 types of fruits and vegetables (spinach, tomato, apple, radish, cabbage and carrot). The method of analysis was the same as reported by Kakimoto et al. in 2003. One hundred and thirty-nine pesticides were spiked by each of 8 laboratories at levels of 0.1 microg/g (pesticides analyzed by GC/MS) or 0.5 microg/g (pesticides analyzed by HPLC) into the 6 kinds of samples. Statistical analysis showed that 111 pesticides could be analyzed with practical precision by this method. For screening purposes, the method could analyze 118 pesticides. The median values of the limits of detection were 0.001-0.041 microg/g. The calibration curves were linear in the range of 0.5-5 microg/mL for most pesticides with median correlation coefficients of 0.983-1.000. 相似文献
2.
Hisako Hirai Satoru Kukino Takeshi Ohwada Ken-ichi Kondo 《Journal of the American Ceramic Society》1995,78(8):2079-2084
The effect of microtexture on diamond transition was examined for graphite starting materials under shock compressions of 50 to 60 GPa and 80 to 90 GPa. Each of the starting materials used in the present study possessed a fully homogeneous microtexture. To distinguish the effect of microtexture from that of other experimental parameters, the shock conditions were standardized for all specimens tested. Three graphite materials—a glassy carbon, a carbon black, and a natural graphite—were selected and shock compressed using a quenching technique to generate conditions common to all samples. Detailed characterization by transmission electron microscopy and electron energy-loss spectroscopy revealed a clear tendency: The lower the crystallinity and crystallite size of the starting graphite, the more easily the graphite transformed to diamond when the transition mechanism was reconstructive. 相似文献
3.
Rats adapted to a corn oil or a fish oil diet were fed a fat-free diet, and changes in phospholipid polyunsaturated fatty
acids (PUFA) in the inner and outer leaflets of liver microsomal membranes were followed for 18 wk. In rats previously adapted
to a corn oil diet, arachidonic acid in phosphatidylcholine and phosphatidylethanolamine in the inner and outer leaflets did
not decrease quickly; rather, linoleic acid decreased more than arachidonic acid for the first three weeks of feeding the
fat-free diet. Even at 18 wk, 40–50% of the beginning arachidonic acid levels were still retained. In contrast, in rats previously
adapted to a fish oil diet, the n−3 PUFA were quickly decreased by the fat-free diet to only 10–30% at 18 wk. Due to the appearance
and increase of n−9 eicosatrienoic acid in the replacement of the n−3 and n−6 PUFA, total PUFA did not decrease in the inner
and outer phosphatidylcholine in either group, but decreased somewhat in the phosphatidylethanolamine due to the insufficient
increase of the n−9. On the other hand, the overall degrees of unsaturation in phosphatidylcholine fatty acids were always
higher in the outer than in the inner leaflets and were not altered by feeding the fat-free diet even for 18 wk. Thus, the
results appear to reveal the physiological importance of unsaturation ratio of fatty acids and the necessity of arachidonic
acid in each membrane leaflet. 相似文献
4.
5.
Yasushi Kawakami Hisako Kojima Kazuo Nakamura Minoru Suzuki Akihiko Uchida Yoshihiko Murata Yoichi Tamai 《Lipids》1995,30(4):333-337
The occurrence of glycosphingolipids with unique carbohydrate structures in different species of cestode, Platyhelminth, which
had been shown, previously, prompted us to study the molecular species of the monohexosylceramides (cerebrosides) in the pseudophyllidean
cestode,Spirometra erinacei. The purpose of the study was to obtain a basis for future investigations of the physiological role of glycolipids in parasitism.
Cerebrosides were isolated froms. erinacei at two growth stages, i.e., from the larval form (plerocercoid) and from the adult tapeworms (intestinal form). The cerebrosides
were separated into four subfractions by silica gel column chromatography, and their constituents were analyzed by gasliquid
chromatography, gas chromatography/mass spectrometry, and high-performance liquid chromatography/mass spectrometry. The hexoses
of the cerebrosides consisted primarily of galactose in both growth stages, while only a small amount of glucose was detected.
The ceramides were composed of sphinganine (d18∶0) and phytosphingosine (t18∶0) as sphingoid bases, and of nonhydroxy fatty
acids ranging from C16 to C30 and hydroxy stearic acid (18h∶0). The cerebrosides of adult tapeworms contained more 18h∶0 than those of plerocercoids. The
combination of hexoses and ceramides in the cerebroside molecules was slightly different in the two growth stages: the glucocerebrosides
of plerocercoids contained only d18∶0-nonhydroxy fatty acids in their ceramide moieties, whereas those of adult tapeworms
contained varying ceramide moieties. Our data indicate that the molecular species of glycolipids present were essentially
homeostatic throughout growth in spite of the entirely different environmental conditions, although there were slight differences
in the hexose distribution in the two growth stages. 相似文献
6.
A bacterium capable of utilizing polyethylene glycol of low molecular weight (less than 300) was isolated from soil and identified as Pseudomonas aeruginosa by biologic characteristics (named P. aeruginosa PEG-K). The effect of ozone degradation on the utilization of polyethylene glycol of high molecular weight by the bacterium was studied on the basis of the measurement of oxygen uptake by Warburg manometer and of bacterial growth. The polyethylene glycol, which can never be utilized at all because of high molecular weight, became utilizable by the bacterium as a result of ozonization, while the formaldehyde produced by the ozonization inhibited the utilization of the ozonized polyethylene glycol by the same bacterium. However, such inhibition disappeared by treating the aldehyde with hydrogen peroxide. From the results of gas chromatography and measurement of chemical oxygen demand, P. aeruginosa PEG-K was found to utilize ethylene glycol, diethylene glycol, and triethylene glycol, which were produced by the ozonization. 相似文献
7.
The Δ- and Λ-isomerism of octahedral metal complexes is employed as a source of chirality for inducing chiral nematic phases. By applying a wide range of chiral metal complexes as a dopant, it has been found that tris(β-diketonato)metal(III) complexes exhibit an extremely high value of helical twisting power. The mechanism of induction of the chiral nematic phase is postulated on the basis of a surface chirality model. The strategy for designing an efficient dopant is described, together with the results using a number of examples of Co(III), Cr(III) and Ru(III) complexes with C2 symmetry. The development of photo-responsive dopants to achieve the photo-induced structural change of liquid crystal by use of photo-isomerization of chiral metal complexes is also described. 相似文献
8.
A method for simultaneous determination of anionic metabolites based on capillary electrophoresis (CE) coupled to electrospray ionization mass spectrometry is described. To prevent current drop by the system, electroosmotic flow (EOF) reversal by using a cationic polymer-coated capillary was indispensable. A mixture containing 32 standards including carboxylic acids, phosphorylated carboxylic acids, phosphorylated saccharides, nucleotides, and nicotinamide and flavin adenine coenzymes of glycolysis and the tricarboxylic acid cycle pathways were separated by CE and selectively detected by a quadrupole mass spectrometer with a sheath-flow electrospray ionization interface. Key to the analysis was EOF reversal using a cationic polymer-coated capillary and an electrolyte system consisting of 50 mM ammonium acetate, pH 9.0. The relative standard deviations of the method were better than 0.4% for migration times and between 0.9% and 5.4% for peak areas. The concentration detection limits for these metabolites were between 0.3 and 6.7 micromol/L with pressure injection of 50 mbar for 30 s (30 nL); i.e., mass detection limits ranged from 9 to 200 fmol, at a signal-to-noise ratio of 3. This method was applied to the comprehensive analysis of metabolic intermediates extracted from Bacillus subtilis, and 27 anionic metabolites could be directly detected and quantified. 相似文献
9.
Ultrafine powder of α-Si3 N4 several tens of nanometers in size was successfully consolidated using a shock-compaction technique under 40 GPa. The bulk density of the most dense portion attained 99% of the theoretical value, and the Vick-ers microhardness was 2300 kg/mm. Consolidation was achieved through both densificarion by plastic deformation of constituent grains and interparticle bonding by surface melting. A transition process to β-Si3 N4 was observed by transmission electron microscopy: Surface melting of the individual grains propagated into the center as temperature increased, and a large mass formed. A precursor of β–Si3N4 then emerged from the mass and finally grew into a β-Si3 N4 crystal. 相似文献
10.
Hisako Hirai Osamu Fukunaga Osamu Odawara 《Journal of the American Ceramic Society》1991,74(7):1715-1718
The effect of microwave power on the hydrogen and amorphous carbon contents of diamond films is investigated by the plasma chemical vapor deposition method. The input microwave power during diamond synthesis is varied between 330 and 500 W by using different holder materials, while a constant substrate temperature of 850°C is maintained. The hydrogen content in the synthesized diamond is measured by secondary ion mass spectrometry, and the relative amount of amorphous carbon is estimated from the Raman spectra. The hydrogen count normalized against that of carbon decreases logarithmically with increasing input power; the amorphous carbon amount also decreases with higher input power. The present experimental results prove that hydrogen content can be controlled by varying input microwave power during diamond deposition. 相似文献