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81.
Novel analogues of the hormone 1alpha,25-(OH)(2)-D(3) with side chains attached to C-18 were synthesized by a versatile route in which key steps were the remote radical-induced functionalization of the 18-methyl by the C-8beta-hydroxyl group and the introduction of the side chains by Wittig reactions on a C-18-aldehyde. The triene system of the novel analogues was constructed by the convergent Lythgoe-Hoffmann la Roche approach, which involves reaction of a phosphine oxide (the ring A fragment) with a ketone (the upper fragment). 相似文献
82.
[reaction: see text] A mild palladium-catalyzed cascade has been used for the synthesis of the hormone 1alpha,25-dihydroxyvitamin D3 (calcitriol, 1a) and its analogues 1b and 1c. This one-pot process involves two consecutive transformations at room temperature: An initial palladium-catalyzed 6-exo-cyclocarbopalladation of vinyl triflates followed by a Negishi cross-coupling reaction with an alkenyl zinc. This novel strategy opens new possibilities for the preparation of a variety of new vitamin D analogues of therapeutic potential, particularly with modifications at the triene and/or ring-A. 相似文献
83.
Mouri E Kaewsaiha P Matsumoto K Matsuoka H Torikai N 《Langmuir : the ACS journal of surfaces and colloids》2004,20(24):10604-10611
The effect of salt concentration on the nanostructure of a spread monolayer of ionic amphiphilic diblock copolymer, (diethylsilacyclobutane)m-b-(methacrylic acid)n, at the air-water interface was directly investigated by in situ X-ray reflectivity and neutron reflectivity techniques. Previously, we had found that a poly(methacrylic acid) (PMAA) hydrophilic layer under the water was not in the form of a simple polyelectrolyte brush but consisted of a dense carpet upper layer and a diffuse brush lower layer when the hydrophilic chain was long enough. Here we observed this double layer formation in the monolayer in aqueous NaCl solution at a constant surface pressure. The effect of salt added to the subphase differed with the salt concentrations, that is, below or above 0.1 M. In the presence of NaCl up to 0.1 M, both the hydrophobic layer and brush layer thicknesses decreased. On the other hand, both of them increased in the presence of NaCl above 0.1 M. Also, the carpet layer thickness was almost constant independent of the salt concentration. In addition, the brush top roughness showed a maximum in the presence of 0.1 M NaCl. The increase of the charge number on the PMAA chain and the screening effect of the Coulomb interaction by added salt ions were considered to be responsible for these phenomena. 相似文献
84.
ECG-gated thallium (201T1) myocardial diastolic imaging and non-gated imaging were performed in 22 patients with myocardial infarction. These patients were separated into 2 groups according to echocardiographic findings; Group A: the patients with left ventricular diastolic diameter of 5.5 cm and over and left ventricular ejection fraction of 50% and under; Group B: the others. In the patients of Group A, the low perfusion areas could be demonstrated qualitatively and quantitatively by nongated images as well as gated-diastolic images, while in some patients of Group B, low perfusion areas were shown only by gated-diastolic images, which seemed to be useful. The images gated in 100 ms after the peak of R wave in ECG were conformed as diastolic images by echocardiography, and could be obtained within a half or two thirds of the conventional imaging time. 相似文献
85.
The T1,2 ← S0 phosphorescence excitation spectrum of 2,4,5-trimethylbenzaldehyde in durene has been simulated using forty-five zero-order Born-Oppenheimer product states of which thirty-two belong to T1 (ππ*), the others to T2 (nπ*). The spectrum is very complicated in the region 400–600 cm?1 above the T1 (ππ*) ←3 S0 origin band at 24150 cm?1. In this tangled region conventional vibrational analysis is not useful. Several comments on the physical properties of the excited triplet states of 2,4,5-trimethylbenzaldehyde are given. 相似文献
86.
The first synthesis of analogues of the natural hormone 1alpha,25-dihydroxyvitamin D(3) (1a) with substituents at C-12 is reported. The following are the relative affinities of the novel compounds for the vitamin D receptor (VDR) compared to that of 1a (100%): 1alpha,12alpha,25-(OH)(3)-D(3) (1b, 1%), 1alpha,25-(OH)(2)-12-methylene-D(3) (1c, 50%), and 1alpha,25-(OH)(2)-12beta-methyl-D(3) (1d, 440%). [structure: see text] 相似文献
87.
A project was undertaken to develop mussel reference materials that were certified for their mass fractions of saxitoxin and decarbamoyl-saxitoxin. Fifteen laboratories from various European countries participated. Three of these had major responsibility for substantial parts of the work and overall coordination of the project. The project involved 4 main activities: (1) procurement and characterization of calibrants; (2) improvement of analytical methodology; (3) preparation of reference materials, including homogeneity and stability studies; (4) 2 interlaboratory studies and a certification exercise. The joint activities resulted in 3 homogeneous and stable reference materials: 2 lyophilized mussel materials with and without naturally incurred paralytic shellfish poisoning (PSP) toxins, and a saxitoxin enrichment solution. The reference materials were certified with respect to their saxitoxin and decarbamoyl-saxitoxin content. The lyophilized mussel material with PSP toxins (CRM 542) contained <0.07 mg saxitoxin x 2HCl/kg and 1.59 +/- 0.20 mg decarbamoyl-saxitoxin x 2HCl/kg. The lyophilized mussel material without PSP toxins (CRM 543) contained <0.07 mg saxitoxin x 2HCl/kg and <0.04 mg decarbamoyl-saxitoxin x 2HCl/kg. The certified value of the saxitoxin mass fraction in the saxitoxin enrichment solution (CRM 663) was 9.8 +/- 1.2 microg/g. 相似文献
88.
Forestier T Mornet S Daro N Nishihara T Mouri S Tanaka K Fouché O Freysz E Létard JF 《Chemical communications (Cambridge, England)》2008,(36):4327-4329
We report the synthesis of spin crossover 69 nm spherical nanoparticles of [Fe(NH(2)-trz)(3)](Br)(2).3H(2)O.0.03(surfactant) (NH(2)trz = 4-amino-1,2,4-triazole, surfactant = Lauropal), prepared by the reverse micelle technique, which exhibit at room temperature a thermal hysteresis characterized by magnetic, diffuse reflectivity and Raman studies. 相似文献
89.
The strong normalization theorem is uniformly proved for typed λ-calculi for a wide range of substructural logics with or
without strong negation.
We would like to thank the referees for their valuable comments and suggestions. This research was supported by the Alexander
von Humboldt Foundation. The second author is grateful to
the Foundation for providing excellent working conditions and generous support of this research.
This work was also supported by the Japanese Ministry of Education, Culture, Sports, Science
and Technology, Grant-in-Aid for Young Scientists (B) 20700015, 2008. 相似文献
90.
Takahiko Masuda Hideaki Hara Yuki Miyamoto Susumu Kuma Itsuo Nakano Chiaki Ohae Noboru Sasao Minoru Tanaka Satoshi Uetake Akihiro Yoshimi Koji Yoshimura Motohiko Yoshimura 《Hyperfine Interactions》2015,230(1-3):73-77
We recently reported an experiment which focused on demonstrating the macro-coherent amplification mechanism. This mechanism, which was proposed for neutrino mass measurements, indicates that a multi-particle emission rate should be amplified by coherence in a suitable medium. Using a para-hydrogen molecule gas target and the adiabatic Raman excitation method, we observed that the two photon emission rate was amplified by a factor of more than 1015 from the spontaneous emission rate. This paper briefly summarizes the previous experimental result and presents the current status and the future prospect. 相似文献