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1.
T Niwa H Yoshizumi A Tatematsu S Matsuura T Nagatsu 《Journal of chromatography. A》1989,493(2):347-352
2.
Six alkaloids have been isolated from the fruits of the plant Daphniphyllaceae. Two of them are new alkaloids, namely methyl homodaphniphyllate (1) and daphnilactone-B (2). The structure of the former was deduced by chemical transformation from daphniphylline (3). The structure of daphnilactone-B was estimated by the exhaustive spectral analysis as well as by chemical evidences, and finally determined by an X-ray crystallographic analysis of the free base. 相似文献
3.
M. Toba S. Tanaka S. Niwa F. Mizukami Z. Koppány L. Guczi 《Journal of Sol-Gel Science and Technology》1998,13(1-3):1037-1041
In order to achieve functional group selective hydrogenation, the layer structure of Ru-Sn-Al2O3 catalysts was controlled by using sol-gel, powder impregnation and combined sol-gel impregnation methods. The properties of the catalysts and effectiveness in hydrogenation of dimethyl terephthalate were examined. The surface Sn contents of the catalysts characterized by X-ray photoelectron spectroscopy depended on the preparation method, in spite of almost the same bulk Ru and Sn compositions measured by X-ray fluorescence analyses. TPR and CO adsorption of the catalysts also depended on the preparation method. With regard to the conversion rate of dimethyl terephthalate and the rate of product conversion from methyl 4-hydroxy methylbenzoate to p-xylene via methyl p-toluate, Ru impregnation catalysts had higher rates than the other catalysts. 相似文献
4.
ATPases are important molecular machines that convert the chemical energies stored in ATP to mechanical actions within the cell. ATPases are among the most abundant proteins with diverse functions involved in almost every cellular pathway. The well characterised ATPases include the various motor proteins responsible for cargo transfers, cell motilities, and muscle contractions; the protein degradation machinery - the proteasome; the ATP synthase, F-ATPase; and the chaperone systems. Other ATPases include DNA helicases and DNA replication complex; proteins responsible for protein/complex disassembly; and certain gene regulators. It is beyond the scope of this review to cover the complete range of ATPases. Instead, we will focus on a few representative ATPases, chosen based on their diverse mechanisms and properties. Furthermore, this review is by no means trying to cover comprehensively the literature for each ATPase nor the historical aspects in each field. We will focus on describing the various techniques being employed to derive the mechanisms and properties of the chosen ATPases. Among them, high and low resolution structural studies combined with biochemical assays seem to be the dominant technical advances adapted to reveal mechanisms for most of the ATPases except the bacterial sigma54 activators, whose mechanism of action is mostly derived from large amount of biochemical studies. A number of them, especially the F-ATPase and motor proteins, have been studied successfully by various single molecule and imaging techniques. We will therefore discuss them in greater details in order to describe the wide range techniques being utilised. 相似文献
5.
From a biogenetic point of view, a great variety of related alkaloids isolated from the plant Daphniphyllaceae are related to one another by bond formation or fission. Thus, daphnialcohol acetate (6), a derivative of the degradation products of daphniphylline (1), was subjected to von Braun degradation followed by acid-catalyzed recyclization to give an isomer (8) of daphnialcohol, which has a new type of nitrogen heterocyclic skeleton. Furthermore, daphnilactone-B (3) was converted into a daphniphylline-type compound (19) via a plausible intermediate (21). 相似文献
6.
The structures of several clerodane-type diterpenes [solidagolactones II (elongatolide C), III, IV (elongatolide A), V, VI (elongatolide D), elongatolide B, and elongatolide E] have been revised , all of which are -clerodanes. 相似文献
7.
Dosimetry of fast neutrons in 1W nuclear reactor with plastic nuclear-track detectors 总被引:1,自引:0,他引:1
A nuclear reactor at Kinki University is operated at the maximum of 1W. It produces fission neutrons as much as gamma-rays. To facilitate its use for neutron radiobiology, fast neutrons inside the reactor were measured with nuclear-track detectors TS 16 N and a pair of ion chambers. The angular dependence of TS 16 N response, an anisotropy of fast neutron fluxes in the reactor and misuse of the kerma factor assumed for radiation protection business are the major causes of discrepancy is measured doses by the two methods. Correction factors for the three causes are proposed. After correction, neutron doses estimated with TS 16 N and chambers agree within 5%. The dose-rate at the reactor's center is about 20 tissue-cGy/h. This is the first in situ dosimetry of fast neutrons in a reactor with track detectors attached to biologic samples. Our routine usage has demonstrated that, if used with caution, TS 16 N elements are handy, reliable monitors for fast neutron dosimetry as they are insensitive to contaminated gamma-rays and small enough to be attached to biologic samples. 相似文献
8.
The organic acids in the urine and serum of diabetic patients with ketoacidosis and disturbance of consciousness were studied using acidification, extraction, evaporation, methoxime formation and trimethylsilylation, gas chromatographic separation and mass spectrometric identification procedures. The organic acid profile of 1 ml of serum ultrafiltrate was obtained with good separation using a gas chromatograph equipped with a glass capillary column and a splitless injector. 5-Hydroxyhexanoic acid and 3-hydroxyvaleric acid were identified for the first time in the urine of diabetic patients with ketoacidosis. Urinary excretion and serum concentrations of 2,3-dideoxypentonic acid were increased in diabetic patients. 相似文献
9.
10.
Mizukami Fujio Maeda Kazuyuki Toba Makoto Sano Tsuneji Niwa Shu-ich Miyazaki Mitsuharu Kojima Kunihiko 《Journal of Sol-Gel Science and Technology》1997,8(1-3):101-106
The preparation of mullite by the sol-gel method using organic polydentate ligands and the effect of the raw materials and
organic polydentate ligands on the formation of mullite were investigated. Two series of samples were prepared using tetraethoxyorthosilicate
(TEOS) and aluminum nitrate nonahydrate, or dibutoxyethylacetoacetatoaluminum (Al(OBu)2(AcAcEt)) as the silica and alumina sources, respectively, and using ethylene glycol (EG), 1,3-propanediol (PD), 1,3-butanediol
(BD), 2-methyl-2, 4-pentanediol (MPD), diethlene glycol monoethyl ether (DEME) and ethoxyethanol as the ligands. When the
alumina source was aluminum nitrate nonahydrate, mullite was apt to appear in the order of EG>PD>MPD. When Al(OBu)2(AcAcEt) was the alumina source, the tendency toward the appearance of mullite crystalline phase was EG>BD>DEME>MPD. Between
the two alumina sources, aluminum nitrate nonahydrate gave mullite much easier than Al(OBu)2(AcAcEt). These relationships were discussed from the viewpoints of the coordination ability of the ligands and the miscibility
between the silica and alumina. 相似文献