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81.
82.
Goshima S Kanematsu M Matsuo M Murakami T Hori M Takamura M Kondo H Kako N Moriyama N Nakamura H Hoshi H 《Magnetic resonance imaging》2004,22(3):379-388
The purpose of our study was to assess whether respiratory-triggered multishot fast spin echo (MS-FSE) and breath-hold half-Fourier single-shot fast spin echo (SS-FSE) images, in addition to breath-hold T(2)*-weighted gradient recalled echo (GRE) images, increase observer performance in the detection of malignant hepatic tumors with ferumoxide-enhanced magnetic resonance (MR) imaging. Ferumoxide-enhanced MR images obtained from 48 patients with 83 malignant hepatic tumors were retrospectively reviewed by three independent off-site readers. In the first image review, GRE images alone were reviewed. Then, MS-FSE images were added for the first combination review. Finally, SS-FSE images were added for the second combination review. Observer performances were tested by McNemar's test and receiver-operating-characteristic analysis for the clustered data. Sensitivity for hepatocellular carcinomas, metastases, and malignant hepatic tumors overall was significantly (p < 0.05) higher with GRE and MS-FSE combined and GRE, MS-FSE and SS-FSE combined than with GRE alone. For metastases, the Az value was significantly (p < 0.05) higher with GRE and MS-FSE combined, and GRE, MS-FSE and SS-FSE combined than with GRE alone. We confirmed the incremental value of ferumoxide-enhanced MR imaging by obtaining MS-FSE and SS-FSE images in addition to GRE images in the detection of malignant hepatic tumors. 相似文献
83.
The effects of fast neutron irradiation near 4.2°K on dilute Cu, Cu3Au, α-CuZn, β-CuZn and CuNi alloys were studied by electrical resistivity measurements. For Cu3Au, the recovery stage at ~ 100°K becomes more distinct with increasing long-range order, and is attributed to migration of interstitials. The ratio of the number of replacements to the number of displacements (C R /C F ) is estimated to be about 50 for neutron irradiation, in contrast to the previously reported value of ~2 for electron irradiation. For α-CuZn, a large recovery stage at ~150°K is found and attributed to annihilation of interstitids whose migration produces ordering. For β-CuZn, migration of interstitials also produces ordering. It is also suggested that in β-CuZn, the ratio C R /C F is larger for neutron irradiation than for electron irradiation as in the case of Cu3Au. The results on CuNi alloys are presented without explanation. 相似文献
84.
The structure, the energetics and the internal redox reactions of La0.7Sr0.3FexMn1−xO3 have been studied in the complete solid solution range 0.0<x<1.0. High temperature oxide melt drop solution calorimetry was performed to determine the enthalpies of formation from binary oxides and the enthalpy of mixing. There is a noticeable change in the energetics of the solid solution near x=0.7, which is due to the growing concentration of Fe4+ at higher Fe/(Fe+Mn) ratio. The balance between different valences of the transition metals, Mn and Fe, is the main factor in determining the energetics of the La0.70Sr0.30FexMn1−xO3 solid solution. 相似文献
85.
Someya CI Inoue S Präsang C Irran E Driess M 《Chemical communications (Cambridge, England)》2011,47(23):6599-6601
Cationic and zwitterionic boryl bromide species and a borenium-boryl bromide cation have been synthesised which represent new N-donor stabilised cationic boron compounds with β-diketiminate ligands. The unexpected borenium-boryl bromide results from a head-to-tail dimerisation of the corresponding zwitterionic boryl bromide accompanied by proton migration. The electronic nature of these new species was studied by DFT calculations. 相似文献
86.
87.
Tsukio Ohtani Shuji Kawasaki Mikio Takano Yoshiaki Harima Takashi Chika Shuichi Kirino 《Molecular Crystals and Liquid Crystals》2013,570(2):39-44
Abstract KCr5Se8 has a TIV5S8-type structure, containing K ions in one-dimensional tunnels. Deintercalated samples of KxCr5Se8 (0.32 ≤ x ≤ 0.93) were prepared by leaching method using Alc3/FeCl3 aqueous solution. These samples showed a broad peak of magnetic susceptibility at ca. 130 K. 57Fe-Mössbauer spectra of Kx(Cr0.95 57Fe0.05)5Se8 (x = 1.0, 0.49) showed a quadrupole doublet at 300 K. Magnetic sextets appeared at 4.2 K in both samples, indicative of magnetic ordering. The observed isomer shift indicated that the charge of Fe is +3 in both samples. It was proposed that Se2- was partially oxidized by the deintercalation. 相似文献
88.
89.
Kumazawa T Hasegawa C Hara K Uchigasaki S Lee XP Seno H Suzuki O Sato K 《Journal of separation science》2012,35(5-6):726-733
A novel method is described for the extraction of methamphetamine, amphetamine, and methylenedioxyphenylalkylamine designer drugs, such as 3,4-methylenedioxy-methamphetamine, 3,4-methylenedioxyamphetamine, 3,4-methylenedioxyethylamphetamine, N-methyl-1-(3,4-methylenedioxyphenyl)-2-butanamine, and 3,4-(methylenedioxyphenyl)-2-butanamine, from human whole blood using molecularly imprinted solid-phase extraction as highly selective sample clean-up technique. Whole blood samples were diluted with 10 mmol/L ammonium acetate (pH 8.6) and applied to a SupelMIP-Amphetamine molecularly imprinted solid-phase extraction cartridge. The cartridge was then washed to eliminate interferences, and the amphetamines of interest were eluted with formic acid/methanol (1:100, v/v). After derivatization with trifluoroacetic anhydride, the analytes were quantified using gas chromatography-mass spectrometry. Recoveries of the seven amphetamines spiked into whole blood were 89.1-102%. The limits of quantification for each compound in 200 μL of whole blood were between 0.25 and 1.0 ng. The maximum intra- and inter-day coefficients of variation were 9.96 and 13.8%, respectively. The results show that methamphetamine, amphetamine, and methylenedioxyphenylalkyl-amine designer drugs can be efficiently extracted from crude biological samples such as whole blood by molecularly imprinted solid-phase extraction with good reproducibility. This extraction method will be useful for the pretreatment of human samples before gas chromatography-mass spectrometry. 相似文献
90.
A convergent synthesis of the A-E ring segment of ciguatoxin CTX3C was achieved via the intramolecular allylation of an α-chloroacetoxy ether and subsequent ring-closing metathesis. 相似文献