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51.
Radicals generated in plastic medical devices (solid phase) by γ-rays or electron-beam irradiation during sterilization are known to cause oxidation of protein drugs, resulting in a loss or reduction in drug efficacy. The generation of radical species in water by the radical species in solid polymers has not been proved. Using electron spin resonance (ESR) spectroscopy, we confirm the generation of new radicals in water by γ-ray irradiated cyclic olefin polymers (COP). ESR measurements are obtained using 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPOL) as a spin probe and 5-(2,2-dimethyl-1,3-propoxycyclophosphoryl)-5-methyl-1-pyrroline N-oxide (CYPMPO) as a spin trap, in which the irradiated COP was immersed. The ESR signals indicate the TEMPOL radicals decline over time, suggesting the generation of new radicals. Conversely, the characteristic ESR signals of the adduct formed by the reaction between CYPMPO and the hydroxyl radical are observed. Thus, hydroxyl radicals are generated because of the migration of the radicals from COP to water. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48604. 相似文献
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55.
Hirahara Y Kimura M Inoue T Uchikawa S Otani S Hirose H Suzuki S Uchida Y 《Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan》2006,47(5):225-231
The applicability of GC, GC/MS and liquid chromatography with tandem mass spectrometry (LC/MS/MS) to screening for 140 pesticides in agricultural products was examined. Validation of multi-residue screening methods for the determination of 88 pesticides in 12 crops (asparagus, cauliflower, burdock, carrot, broccoli, spinach, matsutake mushroom, orange, soybean, sesame, millet and tea) was done by GC and GC/MS. Of the 88 pesticides, 63 were obtained with recoveries in the range from 50 to 150% at the 0.1 microg/g level in the 12 crops. Applicability of the official methods in Japan to 74 pesticides, including 22 pesticides with low recovery (< 50%) by GC or GC/MS analysis, was also examined by LC/MS/MS. LC/MS/MS acquisition parameters were established for 67 pesticides in positive and negative electrospray ionization (ESI) modes. Of 67 pesticides validated in 7 crops using LC/MS/MS at the 0.1 microg/g level, 44 showed recoveries in the range from 50 to 150%. The occurrence of matrix interference in LC/MS/MS can lead to false-positive detection of MCPA in spinach, cabbage and orange and false-negative detection of four pesticides in orange, spinach, apple and unpolished rice. Good linearity was observed in the studied ranges by GC, GC/MS (r > 0.990) and LC/MS/MS (r > 0.995). Of the total of 140 pesticides validated by GC, GC/MS and LC/MS/MS, 107 were newly recognized as suitable subjects for screening. 相似文献
56.
Using mullite (3Al2O3·2SiO2)-tube type and ZrO2 (MgO mole fractions of 9 %)-plug type solid electrolyte, the activities of Al in the Fe-15, 29% Ni-0.002 to 0.84% Al (mass contents in%) alloys were measured at 1873 K in an Al2O3 crucible, and those of Si in the Fe-13, 28% Ni-0.13 to 2.3% Si alloys were measured at 1823 K in a mullite crucible with an excess of SiO2. The interaction coefficients of and were determined as ?0.0173 ± 0.0052 and 0.00021 ± 0.00007, respectively, and those of and were determined as 0.0094 ± 0.0049 and ?0.00008 ± 0.00004, respectively. The oxygen activities obtained by the EMF measurements were compared with those obtained from the contents of analyzed oxygen. The oxygen activities in the Fe-Ni-Al alloys were found to be supersaturated. The interaction coefficients of and were determined as 0.0027 ± 0.0012 and 0.00012 ± 0.00004, respectively, from the contents of analyzed oxygen in Fe-Ni-Si alloys. 相似文献
57.
Using a mullite (3Al2O3 · 2SiO2)-tube and ZrO2-9 mol pct MgO-plug type solid electrolyte galvanic cells, the activities of supersaturated oxygen in Fe-0.0017 to 0.41 mass
pct Al-M (M=C, Te, Mn, Cr, Si, Ti, Zr, and Ce) alloys were measured as a function of total Al or M contents at 1873 K in an alumina
crucible. Based on these results, the effects of alloying elements on the supersaturated oxygen activity with respect to alumina
precipitation were studied. In the Fe-Al-M (M=C, Te, Mn, Cr, and Si) alloys, the supersaturated oxygen activities for a given Al level approach the equilibrium values
with increasing contents of alloying elements. However, the oxygen activities for a given Al level are still supersaturated
in the Fe-Al-M (M=Ti, Zr, and Ce) alloys even in the presence of considerable amounts of the alloying elements. 相似文献
58.
Hideaki Katayama Tsutomu Tawa Shinzaburo Ito Masahide Yamamoto Yoshio Wada 《Polymer Bulletin》1992,29(3-4):365-367
Summary The effect of side chain length on intramolecular triplet energy migration of naphthalene containing polymers was investigated by a delayed fluorescence (DF) spectroscopy for the solid solution of the polymers. The degree of triplet energy migration depends strongly on whether the chromophores are directly attached to the main chain or not. 相似文献
59.
Ryuta Shigefuku Hideaki Takahashi Hiroyasu Nakano Tsunamasa Watanabe Kotaro Matsunaga Nobuyuki Matsumoto Masaki Kato Ryo Morita Yousuke Michikawa Tomohiro Tamura Tetsuya Hiraishi Nobuhiro Hattori Yohei Noguchi Kazunari Nakahara Hiroki Ikeda Toshiya Ishii Chiaki Okuse Shigeru Sase Fumio Itoh Michihiro Suzuki 《International journal of molecular sciences》2016,17(9)
The progression of chronic liver disease differs by etiology. The aim of this study was to elucidate the difference in disease progression between chronic hepatitis C (CHC) and nonalcoholic fatty liver disease (NAFLD) by means of fibrosis markers, liver function, and hepatic tissue blood flow (TBF). Xenon computed tomography (Xe-CT) was performed in 139 patients with NAFLD and 152 patients with CHC (including liver cirrhosis (LC)). The cutoff values for fibrosis markers were compared between NAFLD and CHC, and correlations between hepatic TBF and liver function tests were examined at each fibrosis stage. The cutoff values for detection of the advanced fibrosis stage were lower in NAFLD than in CHC. Although portal venous TBF (PVTBF) correlated with liver function tests, PVTBF in initial LC caused by nonalcoholic steatohepatitis (NASH-LC) was significantly lower than that in hepatitis C virus (C-LC) (p = 0.014). Conversely, the liver function tests in NASH-LC were higher than those in C-LC (p < 0.05). It is important to recognize the difference between NAFLD and CHC. We concluded that changes in hepatic blood flow occurred during the earliest stage of hepatic fibrosis in patients with NAFLD; therefore, patients with NAFLD need to be followed carefully. 相似文献
60.
Kuniaki Kawaguchi Kazuhiro Mizuguchi Katsutoshi Suzuki Hideaki Sakamoto Toshio Oguni 《应用聚合物科学杂志》2010,118(4):1910-1920
We investigated the mechanical and physical characteristics of composites composed of polyacetal [alternatively called polyoxymethylene (POM)] and cellulose fiber (CelF) derived from wood pulp [10–52 wt % (9.3–50.1 vol %)] without any fiber surface treatment. The modulus, deflection temperature under load, and thermal conduction coefficient of the POM/CelF composites were effectively enhanced with increasing CelF content, and the composites had an advantage of specific modulus compared to glass fiber (GF)‐filled POM. The flexural modulus of POM/CelF 40 wt % (38.2 vol %) was measured to be about 6 GPa, which was comparable to that of POM/GF 20 wt % (12.1 vol %). In the composites, the CelFs were distributed randomly as monofilaments, and the debonding of the interface between the fibers and POM matrices in the fracture faces was confirmed as less by scanning electron microscopy observation. The POM/CelF composites possessed lower specific wear rates than the POM/GF composites, and they had damping behaviors near that of neat POM. No clear dependence of the melt flow index of the base POM on these characteristics was observed, except on Charpy impact strength. The composites studied here were unique in their performance and ability to be designed in accordance with specific demands, and they could be potential replacements for mineral‐filled and GF‐filled POM composites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献