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排序方式: 共有93条查询结果,搜索用时 13 毫秒
1.
Yasumitsu Matsuo Takehiko Ijichi Hironori Yamada Junko Hatori Seiichiro Ikehata 《Central European Journal of Physics》2004,2(2):357-366
We have fabricated a field effect transistor (FET) based on an organic ferroelectric insulator and molecular conductor, and
investigated the electrical properties and memory effects on the PEN-FET. We have observed a drastic change in the drain current
at around the coercive electric fieldE
c
of the organic ferroelectric insulator in not only a FET (PEN-FET) based on a pentacene (PEN) film but also a FET (IPEN-FET)
based on an iodine doped PEN film. The magnitude of the change of the drain current for the IPEN-FET is 200 times larger than
that for the PEN-FET. It is expected from these results that the PEN-FET (especially the IPEN-FET) is an improvement in such
devices, since it operates at a low gate electric field accompanied by the appearance of the spontaneous polarization in the
organic ferroelectric insulator. In addition, we have found that the drain current for the PEN-FET does not return to the
initial drain current ofE
G
=0 V/cm for more than one week, even if the gate electric field is changed to 0 V/cm from 500 V/cm(>E
c
). From these results, it is suggested that the PEN-FET becomes a memory device. 相似文献
2.
3.
Speciation of metabolites of selenate in rats by HPLC-ICP-MS 总被引:2,自引:0,他引:2
The metabolic pathway for and metabolites of selenium (Se) administered intravenously to rats in the form of selenate at a dose of 0.3 mg Se kg-1 body weight were studied by speciating Se in the bloodstream, liver and urine by HPLC-inductively coupled argon plasma mass spectrometry. Selenate was not taken up by red blood cells (RBCs) and disappeared from the bloodstream much faster than selenite, without any change in its chemical form before it disappeared from the plasma. Selenium excreted into the urine after the administration of selenate showed different patterns from those of selenite in both amounts and chemical forms. With the selenate group, the concentration of Se in urine was highest at 0-6 h and the chemical species of Se was selenate at 0-6 h; thereafter a monomethylselenol-related Se compound (MMSe*) and trimethylselenonium ions (TMSe) appeared, selenate not being excreted after 6 h. On the other hand, in the selenite group, the concentration of Se peaked at 6-12 h, and the chemical species of Se were MMSe* and TMSe. Selenate was reduced in vitro on incubation in either a liver homogenate or supernatant fraction, although much more slowly than in the whole body. Selenate was not reduced by glutathione or dithiothreitol. The results suggest that in contrast to selenite, which is taken up by and reduced in RBCs, and then transferred to the liver, approximately 20% of the selenate administered to rats was excreted into the urine without any change in its chemical form with the present dose, and the major portion of selenate was taken up by the liver, reduced and then utilized for the synthesis of selenoproteins or excreted into the urine after being methylated. 相似文献
4.
Fumihiko Hasumi Yasumitsu Miyamoto Ichiro Okura 《Applied biochemistry and biotechnology》1995,55(1):1-4
Glutamate synthesis by reductive amination of 2-oxoglutarate was performed by the combination of NADH regeneration system
and glutamate dehydrogenase (GluDH). The conversion of 2-oxoglutamate to glutamate was 98% after 3 h, and the turnover number
of NAD+was 17. 相似文献
5.
Fumihiko Hasuni Katsunori Fukuoka Shuichi Adachi Yasumitsu Miyamoto Ichiro Okura 《Applied biochemistry and biotechnology》1996,56(3):341-344
Alanine synthesis by reductive amination of pyruvate was performed by the combination of NADH regeneration system and alanine
dehydrogenase (AlaDH). The conversion of pyruvate to alanine was 99% after 1 h. Leucine synthesis was also carried out by
the combination of NADH regeneration system and leucine dehydrogenase (LeuDH). The conversion of 4-methyl-2-oxovalerate to
leucine was 60% after 1.5 h. 相似文献
6.
Yasumitsu Tamura Yasuyoshi Miki Yoshinori Nishikawa Masazumi Ikeda 《Journal of heterocyclic chemistry》1976,13(2):317-320
N-Aminophenanthridinium salt reacted with dimethyl acetylenedicarboxylate in the presence of potassium carbonate to give a 3,3a-dihydropyrazolo[1,5-f]phenanthridine but with mono-substituted acetylenes (ethyl propiolate and benzoylacetylene) it produced aromatized pyrazolo-[1,5-f]phenanthridines (XII and XIII). The reaction of the N-benzoylimine with di-substituted acetylenes (dimethyl acetylenedicarboxylate and methyl phenylpropiolate) and mono-substituted acetylenes (ethyl propiolate and benzoylacetylene) yielded 1,3a-dihydropyrazolo[1,5-f]phenanthridines and the aromatized products (XII and XIII), respectively. 相似文献
7.
8.
Dr. Jinying Zhang Zhen Zhu Prof. Dr. Yanquan Feng Hitoshi Ishiwata Dr. Yasumitsu Miyata Dr. Ryo Kitaura Dr. Jeremy E. P. Dahl Prof. Dr. Robert M. K. Carlson Dr. Natalie A. Fokina Prof. Dr. Peter R. Schreiner Prof. Dr. David Tománek Prof. Dr. Hisanori Shinohara 《Angewandte Chemie (International ed. in English)》2013,52(13):3536-3536
9.
Inside Back Cover: Size‐Selective Complexation and Extraction of Endohedral Metallofullerenes with Cycloparaphenylene (Angew. Chem. Int. Ed. 12/2014)
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10.
Speciation of arsenic in body fluids 总被引:1,自引:0,他引:1
Inorganic arsenic is metabolized by consecutive reduction and methylation reactions to dimethylated arsenic (DMA), and then excreted into the urine mostly in the form of DMA. Therefore, arsenic metabolites in the body fluids and organs/tissues are present in the form of inorganic (arsenite and arsenate) and methylated arsenics (MMA and DMA). Although pentavalent arsenics can be present mostly in the form of free ions, trivalent ones may be present more in the forms conjugated with thiol groups of glutathione (GSH) or proteins. Arsenic in the body fluids (plasma, bile and urine) is present in the soluble forms and can be speciated on ion exchange columns by HPLC with on-line detection by an inductively coupled argon plasma-mass spectrometer (ICP-MS). Free forms of arsenite, arsenate, and monomethylarsonous, monomethylarsonic, dimethylarsinous and dimethylarsinic acids in the body fluids have been demonstrated to be speciated simultaneously within 10 min or so on both anion and cation exchange columns together with arsenobetaine (AsB) and arsenocholine (AsC). Trivalent arsenics conjugated with GSH were eluted in intact forms on an anion exchange column but were liberated into free forms on a cation exchange column. Thus, free and GSH-conjugated arsenic metabolites in the bile and urine have been speciated simultaneously on ion exchange columns by HPLC-ICP-MS. 相似文献