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排序方式: 共有952条查询结果,搜索用时 15 毫秒
941.
Kazuaki Wagatsuma 《Analytical and bioanalytical chemistry》2009,393(8):2067-2074
The emission characteristics of ionic lines of nickel, cobalt, and vanadium were investigated when argon or krypton was employed
as the plasma gas in glow discharge optical emission spectrometry. A dc Grimm-style lamp was employed as the excitation source.
Detection limits of the ionic lines in each iron-matrix alloy sample were compared between the krypton and the argon plasmas.
Particular intense ionic lines were observed in the emission spectra as a function of the discharge gas (krypton or argon),
such as the Co II 258.033 nm for krypton and the Co II 231.707 nm for argon. The explanation for this is that collisions with
the plasma gases dominantly populate particular excited levels of cobalt ion, which can receive the internal energy from each
gas ion selectively, for example, the 3d74p 3G5 (6.0201 eV) for krypton and the 3d74p 3G4 (8.0779 eV) for argon. In the determination of nickel as well as cobalt in iron-matrix samples, more sensitive ionic lines
could be found in the krypton plasma rather than the argon plasma. Detection limits in the krypton plasma were 0.0039 mass%
Ni for the Ni II 230.299-nm line and 0.002 mass% Co for the Co II 258.033-nm line. However, in the determination of vanadium,
the argon plasma had better analytical performance, giving a detection limit of 0.0023 mass% V for the V II 309.310-nm line. 相似文献
942.
Ninomiya K Ogino C Oshima S Sonoke S Kuroda S Shimizu N 《Ultrasonics sonochemistry》2012,19(3):607-614
Our previous study suggested new sonodynamic therapy for cancer cells based on the delivery of titanium dioxide (TiO2) nanoparticles (NPs) modified with a protein specifically recognizing target cells and subsequent generation of hydroxyl radicals from TiO2 NPs activated by external ultrasound irradiation (called TiO2/US treatment). The present study first examined the uptake behavior of TiO2 NPs modified with pre-S1/S2 (model protein-recognizing hepatocytes) by HepG2 cells for 24 h. It took 6 h for sufficient uptake of the TiO2 NPs by the cells. Next, the effect of the TiO2/US treatment on HepG2 cell growth was examined for 96 h after the 1 MHz ultrasound was irradiated (0.1 W/cm2, 30 s) to the cells which incorporated the TiO2 NPs. Apoptosis was observed at 6 h after the TiO2/US treatment. Although no apparent cell-injury was observed until 24 h after the treatment, the viable cell concentration had deteriorated to 46% of the control at 96 h. Finally, the TiO2/US treatment was applied to a mouse xenograft model. The pre-S1/S2-immobilized TiO2 (0.1 mg) was directly injected into tumors, followed by 1 MHz ultrasound irradiation at 1.0 W/cm2 for 60 s. As a result of the treatment repeated five times within 13 days, tumor growth could be hampered up to 28 days compared with the control conditions. 相似文献
943.
We summarize the original formulation of the free energy principle and highlight some technical issues. We discuss how these issues affect related results involving generalised coordinates and, where appropriate, mention consequences for and reveal, up to now unacknowledged, differences from newer formulations of the free energy principle. In particular, we reveal that various definitions of the “Markov blanket” proposed in different works are not equivalent. We show that crucial steps in the free energy argument, which involve rewriting the equations of motion of systems with Markov blankets, are not generally correct without additional (previously unstated) assumptions. We prove by counterexamples that the original free energy lemma, when taken at face value, is wrong. We show further that this free energy lemma, when it does hold, implies the equality of variational density and ergodic conditional density. The interpretation in terms of Bayesian inference hinges on this point, and we hence conclude that it is not sufficiently justified. Additionally, we highlight that the variational densities presented in newer formulations of the free energy principle and lemma are parametrised by different variables than in older works, leading to a substantially different interpretation of the theory. Note that we only highlight some specific problems in the discussed publications. These problems do not rule out conclusively that the general ideas behind the free energy principle are worth pursuing. 相似文献
944.
945.
Islam Md. Rafiqul Kazuaki Shimada Shigenobu Aoyagi Yuji Takikawa Chizuko Kabuto 《Heteroatom Chemistry》2004,15(2):175-186
5H-1,2,4-oxathiazoles were efficiently synthesized from 6H-1,3,5-oxathiazine S-oxides by thermal cycloreversion of the substrates and the products were effectively converted into 1,2,4-thiadiazoles. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:175–186, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20004 相似文献
946.
947.
Satoru Yoshioka Kazuaki Toyoura Fumiyasu Oba Akihide Kuwabara Katsuyuki Matsunaga Isao Tanaka 《ChemInform》2008,39(14):no-no
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option. 相似文献
948.
949.
950.
Islam Md. Rafiqul Kazuaki Shimada Shigenobu Aoyagi Yoriko Fujisawa Yuji Takikawa 《Heteroatom Chemistry》2004,15(3):208-215
Treatment of 6H-1,3,5-oxathiazine S-oxides by Lawesson's reagent (LR) at high temperature furnished 3H-1,2,4-dithiazoles in moderate to good yields. Deoxygenation of 6H-1,3,5-oxathiazine S-oxides was performed by LR in the presence of EtOH. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:208–215, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20011 相似文献