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排序方式: 共有137条查询结果,搜索用时 15 毫秒
31.
Seung Wha Lee Sang Hoon ChaHwan Hoon Chung Kee Hwan KimSuk Keu Yeom Bo Kyung SeoBo Kyung Je Baek Hyun Kim 《Magnetic resonance imaging》2014
Purpose
To describe the patterns of bile distribution in the biliary tree, duodenum, jejunum, and stomach, and to determine the gallbladder ejection fraction (GBEF) by using functional magnetic resonance cholangiography (MRC) with gadolinium-ethoxybenzyl-diethylenetriamine penta-acetic acid (Gd-EOB-DTPA) in healthy volunteers.Materials and Methods
Forty subjects were included in this study. After conventional MRC, pre-fatty meal MRC (PRFM) was obtained at 30, 40, 50, and 60 min after contrast agent injection. Then, post-fatty meal MRC (POFM) was obtained every 10 min for 1 h. We assessed the PRFM and POFM for opacification of contrast agent in the first- and second-order intrahepatic ducts (IHDs) and the common bile duct (CBD). Contrast agent opacification in the cystic duct was assessed, and the percentage volume of contrast agent filling in the gallbladder (GB) was calculated on PRFM. We calculated the GBEF and assessed the presence of contrast agent in the GB, duodenum, jejunum, and stomach.Results
Thirty-six (90%) subjects showed grade 3 CBD opacification (visible contrast and well-defined bile duct border) on 60-min PRFM. Thirty-four (85%) subjects showed grade 3 first-order IHD opacification on 60-min PRFM. All (100%) subjects showed cystic duct opacification of contrast agent, and the average percentage volume of contrast agent filling in the GB was 68.81% ± 16.84% on 60-min PRFM. The GBEF at 30-min POFM was 35.00% ± 18.26%. Ten (25%) subjects had no contrast agent in the stomach and small bowel on all PRFMs. Twelve (30%) subjects had contrast medium in the stomach on PRFM and/or POFM.Conclusions
Functional MRC with Gd-EOB-DTPA can allow determining the distribution of bile in the biliary tree and small intestine, as well as the GBEF. 相似文献32.
Y. Fukaya I. Matsuda M. Hashimoto K. Kubo T. Hirahara S. Yamazaki W.H. Choi H.W. Yeom S. Hasegawa A. Kawasuso A. Ichimiya 《Surface science》2012,606(11-12):919-923
The atomic structures of Au and Ag co-adsorption-induced √21 × √21 superstructure on a Si(111) surface, i.e., (Si(111)-√21 × √21-(Au, Ag)), where the Si(111)-5 × 2-Au surface is used as a substrate, have been investigated using reflection high-energy positron diffraction (RHEPD) and photoemission spectroscopy. From core-level spectra, we determined the chemical environments of Ag and Au atoms present in the Si(111)-√21 × √21-(Au, Ag) surface. From the rocking curve and pattern analyses of RHEPD, we found that the atomic coordinates of the Au and Ag atoms were approximately the same as those of the Au and Ag atoms in other Si(111)-√21 × √21 surfaces with different stoichiometries. On the basis of the core-level and RHEPD results, we revealed the atomic structure of the Si(111)-√21 × √21-(Au, Ag) surface. 相似文献
33.
34.
Bruins EE Bauer TS den Bok HW Duif CP van Hoek WC de Lange DJ Misiejuk A Papandreou Z Sichtermann EP Tjon JA Willering HW Yeomans DM Reike H Durek D Frommberger F Gothe R Jakob D Kranefeld G Kunz C Leiendecker N Pfeiffer G Putsch H Reichelt T Schoch B Wacker D Wehrmeister D Wilhelm M Jans E Konijn J de Vries R Furget C Voutier E Arenhövel H 《Physical review letters》1995,75(1):21-24
35.
36.
Jin-Seong ParkChang-Eun Yeom Soo Hyuk ChoiYong Shik Ahn Sunggu Ro Young Ho Jeon Dong-Kyu Shin B.Moon Kim 《Tetrahedron letters》2003,44(8):1611-1614
An orthogonally protected β,γ′-diamino acid 6 possessing conformationally-constrained ring system was synthesized as a novel cyclic amino acid analogue. This synthesis involves as key steps chemoselective enzymatic hydrolysis of cis-piperidine-3,5-dicarboxylic ester derivative followed by efficient kinetic resolution of the partially resolved half-acid to afford the C1-symmetric piperidine-3,5-dicarboxylic acid monoester in high enantiomeric excess (>98% ee). The optically active half-acid was transformed to the cyclic amino acid via Curtius-type rearrangement. 相似文献
37.
MnAPO-11 molecular sieves with medium size elliptical pore are synthesized and characterized. Transition state shape-selective catalysis of these molecular sieves are studied. Methylation of alkylaromatic compounds were efficiently catalyzed by these molecular sieves while aromatic ethylation was almost negligible. The size of the alkylating agents was the key factor for the transition state dimension in the aromatic alkylation, not the size of aromatic compounds. The mole fraction of o-isomer for methylation of alkylaromatic compounds was dependent on the size of the alkyl groups. 相似文献
38.
39.
Spray freeze-drying is a promising technology for producing high-quality porous particles primarily for pharmaceutical uses.
The advantages of freeze-drying in the production of pharmaceuticals and biomedical products, such as minimization of thermal
and chemical degradation, retention of volatile components, preservation of high porosity, and a very low content of residual
water after drying, are mostly retained in spray freeze-drying. In this study, we performed spray freeze-drying of a 3% (w/w)
chicken egg ovalbumin solution in a tray with a batch-type spray freeze-dryer that we developed. The physical characteristics
of the spray freeze-dried particles were qualitatively evaluated by means of scanning electron microscopy. The freeze-drying
behavior of spray-frozen particles was experimentally investigated by measuring the histories of product temperatures and
numerically studied by developing an analysis model based on the finite volume method in a fixed grid system. 相似文献
40.
Kyong Nam Kim Jong Hyeuk Lim Geun Young Yeom 《Plasma Chemistry and Plasma Processing》2010,30(1):183-190
Plasma and electrical characteristics of an internal-type inductively coupled plasma source with a Ni–Zn ferrite module installed
near the antenna were investigated for different rf power frequencies of 2 and 13.56 MHz. Due to the lower heating of the
Ni–Zn ferrite module on the antenna for the operation at 2 MHz compared to the operation at 13.56 MHz, higher plasma density
and lower rf rms antenna voltage were resulted for the operation at 2 MHz in addition to more stable plasma characteristics.
By the application of 500 W of rf power to the source, a high plasma density of 8 × 1011 cm−3 which is about four times higher than that with 13.56 MHz could be obtained at the pressure of 10 mTorr Ar. When photoresist
etch uniformity was measured for the operation with 2 MHz by etching photoresist on a 300 mm diameter substrate using 10 mTorr
Ar/O2 (9:1) mixture, the etch uniformity of about 5.5% could be obtained. 相似文献