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排序方式: 共有93条查询结果,搜索用时 31 毫秒
31.
Nakano T Yagi Y Miyahara M Kaminura A Kawatsura M Itoh T 《Molecules (Basel, Switzerland)》2011,16(8):6747-6757
Optical resolution of 2-methyl-2-nitrobut-3-en-1-ol has been accomplished using a "low-temperature lipase-catalyzed transesterification" carried out at -40 °C. 相似文献
32.
Koji Kamagata Hiroyuki Tomiyama Yumiko Motoi Masayoshi Kano Osamu Abe Kenji Ito Keigo Shimoji Michimasa Suzuki Masaaki Hori Atsushi Nakanishi Ryohei Kuwatsuru Keisuke Sasai Shigeki Aoki Nobutaka Hattori 《Magnetic resonance imaging》2013
Objective
The pathological changes in Parkinson disease begin in the brainstem; reach the limbic system and ultimately spread to the cerebral cortex. In Parkinson disease (PD) patients, we evaluated the alteration of cingulate fibers, which comprise part of the limbic system, by using diffusional kurtosis imaging (DKI).Methods
Seventeen patients with PD and 15 age-matched healthy controls underwent DKI with a 3-T MR imager. Diffusion tensor tractography images of the anterior and posterior cingulum were generated. The mean kurtosis (MK) and conventional diffusion tensor parameters measured along the images in the anterior and posterior cingulum were compared between the groups. Receiver operating characteristic (ROC) analysis was also performed to compare the diagnostic abilities of the MK and conventional diffusion tensor parameters.Results
The MK and fractional anisotropy (FA) in the anterior cingulum were significantly lower in PD patients than in healthy controls. The area under the ROC curve was 0.912 for MK and 0.747 for FA in the anterior cingulum. MK in the anterior cingulum had the best diagnostic performance (mean cutoff, 0.967; sensitivity, 0.87; specificity, 0.94).Conclusions
DKI can detect alterations of the anterior cingulum in PD patients more sensitively than can conventional diffusion tensor imaging. Use of DKI can be expected to improve the ability to diagnose PD. 相似文献33.
K. Takahiro S. Oizumi K. Kawatsura K. Nishio S. Yamamoto H. Naramoto 《Applied Surface Science》2009,256(4):1061-1064
In X-ray photoelectron spectroscopy (XPS) of Au nanoparticles, the width of 5d valence band changes with Au particle size. This enables us to estimate the size of Au nanoparticles by using XPS. In this work, the 5d-band width has been measured for Au nanoparticles formed by ion implantation into SiO2. The 5d-band width is found to be correlated strongly with the Au concentration. As the Au concentration increases, the 5d-band width becomes larger, indicating that the Au nanoparticles with the larger size tend to be formed in the vicinity of the projected range of Au ions. This correlation agrees very well with the results from transmission electron microscopy. 相似文献
34.
We point out that the inflaton spontaneously decays into any gauge bosons and gauginos via the super-Weyl, Kähler and sigma-model anomalies in supergravity, once the inflaton acquires a non-vanishing vacuum expectation value. In particular, in the dynamical supersymmetry breaking scenarios, the inflaton necessarily decays into the supersymmetry breaking sector, if the inflaton mass is larger than the dynamical scale. This generically causes the overproduction of the gravitinos, which severely constrains the inflation models. 相似文献
35.
5,6-Unsubstituted 1,3-oxazine-2,4-diones ( 3 ) and 6-unsubstituted 5-methyl-1,3-oxazine-2,4-diones ( 4 ) were prepared by reduction of the corresponding 6-chloro derivatives ( 1 and 2 ). Treatment of 6-chloro-3-methyl-1,3-oxazine-2,4-dione ( 1a ) with sodium azide, sodium cyanide, secondary amines and aniline gave the corresponding 6-substituted compounds ( 7, 9, 10 and 11 ) while the reaction of 1a and 2a,b with primary aliphatic amines such as methylamine and ethylamine caused a ring transformation to pyrimidine ring system giving barbituric acids ( 13a-d ). 相似文献
36.
Motoi Oishi Hisato Hayashi Keiji Itaka Kazunori Kataoka Yukio Nagasaki 《Colloid and polymer science》2007,285(9):1055-1060
A pH-responsive PEGylated nanogel was successfully prepared by means of emulsion copolymerization of 2-(N,N-diethylamino)ethyl methacrylate (AMA) with heterobifunctional poly(ethylene glycol) (PEG) bearing a 4-vinylbenzyl group at
the α-end and a lactose moiety at the ω-end in the presence of potassium persulfate and ethyleneglycol dimethacrylate as a
cross-linker. Polyplex micelle composed of PEG-block-poly(l-lysine) copolymer and plasmid DNA (PEG-b-PLL/pDNA) exhibited a far more efficient transfection ability in the presence of lac-nanogel-8k-1.0% (PEG, M
n = 8000; cross-linking density, 1.0%) than the PEG-b-PLL/pDNA polyplex micelle alone (in the absence of lac-nanogel-8k-1.0%), suggesting that an appreciable fraction of lac-nanogel-8k-1.0%
along with the PEG-b-PLL/pDNA polyplex micelle is taken up into the HuH-7 cells through the asialoglycoprotein receptor-mediated endocytosis process
mediated by the cluster of a large number of lactose moieties on the surface of lac-nanogel-8k-1.0%, followed by the effective
disruption of the endosome by the buffer effect of the unprotonated PAMA core in lac-nanogel-8k-1.0%.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
37.
Yuan X Iijima M Oishi M Nagasaki Y 《Langmuir : the ACS journal of surfaces and colloids》2008,24(13):6903-6909
Enzyme/polymer/gold nanoparticle hybrids, called "nanozymes", were prepared and structurally analyzed by dynamic light scattering (DLS), ultraviolet-visible spectroscopy, and zeta-potential and transmission electron microscopy (TEM) measurements, which showed that the nanozyme particles were mainly composed of a single gold nanoparticle, on whose surface the enzyme and polymer were coimmobilized. This kind of structure resulted in the high dispersion stability of the nanozyme under various conditions, accompanied by improved thermal stability of the enzyme. 相似文献
38.
Yasuhiro Tanoue Takashi Motoi Yutaka Masuda Norihisa Kai Kazunori Sakata Mamoru Hashimoto Takeshi Nagai 《Journal of heterocyclic chemistry》2008,45(5):1509-1511
Asterriquinone D was easily synthesized in three steps from 2,5‐dichloro‐1,4‐benzoquinone. The reaction of benzoquinone with indole in the presence of Pd(OAc)2, followed by oxidation with cerium (IV) ammonium nitrate (CAN) produced 3,6‐dichloro‐2,5‐bis (3‐indolyl)‐1,4‐benzoquinone. The methoxylation of the dichloride with NaOH in CH3OH afforded asterriquinone D. 相似文献
39.
Magnesium and coconuts shell activated carbon composite was prepared to selectively remove heavy metals ions in aqueous solution. Zinc(II) and cadmium(II) ions were used to clarify the adsorption capacity of the composite in comparison with no magnesium containing activated carbon. Influence of the initial heavy metal concentration, time course and solution temperature on the adsorption amounts were examined for the two adsorbents, and surface chemistry of the adsorbents was also characterized using Boehm titration. The magnesium composite adsorbed greater amount of Zn(II) and Cd(II) ions than the no magnesium counterpart. The adsorption amount of Cd(II) was not influenced with rise in solution temperature for the composite, whereas decrease in adsorption was observed for the counterpart. The loaded magnesium was estimated to be combined with carbon surface via oxygen bridge. Cadmium(II) was adsorbed onto the composite surface by ion exchange process with releasing equivalent amount of Mg(II) from the carbon surface, while Zn(II) would adsorb onto the composite by not only the ion exchange, but also the electrostatic interaction with the Cπ electrons on the graphite surface from the experimental results. 相似文献
40.
Colloid and Polymer Science - 相似文献