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101.
The labeling of oligo- and polynucleotides with fluorescent probes is an important technique for the analysis of DNAs and RNAs. The effect of duplex formation with complementary oligo-DNA on the quenching behavior of two fluorescent chromophores (eosin, Eo and tetramethylrhodamine, TMR) attached to the 5′-terminal of various 10mer oligo-DNAs was investigated and the dependence of the quenching on DNA base sequence is discussed. We found that guanine residues played a major role in the quenching of the fluorescence of the chromophores. Guanine residues on the complementary DNA near the chromophores, in particular, had a significant influence on the quenching. 相似文献
102.
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103.
104.
Understanding the quantitative analysis of the transition adsorption structures of molecules on single‐walled carbon nanotubes (SWNTs) is of importance from the point of view of both fundamental science and applications of nanotubes. Absorption spectroscopy reveals that two different equilibrium states are existent for the exchange reaction of sodium cholate (SC) and oligo‐DNA (single‐stranded 20‐mer cytosine) on SWNTs. This is derived from the transitions of the adsorption structures of different chirality‐types of SWNTs and SC/DNA at certain SC concentrations below the critical micelle concentration of SC. 相似文献
105.
Yuichi Hashiguchi Shin-ichi Zaitsu Totaro Imasaka 《Analytical and bioanalytical chemistry》2013,405(22):7053-7059
The fourth harmonic emission (200 nm) of a femtosecond Ti:sapphire laser (35 fs) was generated and used in the multiphoton ionization of 49 pesticides in gas chromatography/time-of-flight mass spectrometry. The limit of detection was improved when the ionization source from the third harmonic emission (267 nm) was replaced with the fourth harmonic emission for several pesticide molecules that contained no conjugated double bonds since their absorption bands are located in the far-ultraviolet region. This analytical instrument was used in the analysis of a series of real samples including potatoes, carrots, and cabbage, and a signal suspected to arise from di-allate was observed for the potato sample.
Figure 相似文献
106.
Makoto Kunisada Taro Masaki Ryusuke Ono Hironobu Morinaga Eiji Nakano Flandiana Yogianti Kunihiro Okunishi Hiroshi Sugiyama Chikako Nishigori 《Photochemistry and photobiology》2013,89(3):649-654
The UVA is currently thought to be carcinogenic because, similar to UVB, it induces the formation of cyclobutane pyrimidine dimers (CPDs). Various drugs have been reported to cause photosensitive drug eruptions as an adverse effect. Although the precise mechanism of photosensitive drug eruption remains to be elucidated, it is generally accepted that free radicals and other reactive molecules generated via UV‐irradiated drugs play important roles in the pathogenesis of photosensitive drug eruptions. The waveband of concern for photo‐reactive drugs is UVA‐visible light, but some extend into the UVB region. We tested whether photosensitive drugs could enhance CPD formation after UVA exposure by using isolated DNA in the presence of several reported photosensitive drugs using high‐performance liquid chromatography. We found that the diuretic agent hydrochlorothiazide (HCT) significantly enhanced the production of TT dimers over a wide range of UVA. Furthermore, we investigated whether UVA plus HCT could enhance CPD production in xeroderma pigmentosum model mice defective in nucleotide excision repair. Immunofluorescence studies showed that CPD formation in the skin significantly increased after 365 nm narrow‐band UVA irradiation in the presence of HCT, compared with that in wild‐type mice. HCT could be used with caution because of its enhancement of UVA‐induced DNA damage. 相似文献
107.
Kazuya Tanaka Hokuto Iwatani Aya Sakaguchi Yoshio Takahashi Yuichi Onda 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(3):2007-2014
We analyzed fresh and dead leaves collected in forests in Fukushima after the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, using autoradiography. Both fresh and dead leaves of Cryptomeria japonica were contaminated by radionuclides (134Cs and 137Cs). Contamination of the fresh leaves was possibly attributed to interception of radionuclides by tree canopies, whereas the dead leaves indicated the direct deposition of radionuclides by fallout and/or washout of radionuclides intercepted by tree canopies. Translocation of radiocesium from a contaminated branch to new leaves growing after the FDNPP accident was not clearly observed, although transfer of radiocesium from leaf parts to male flowers occurred. Fallen leaves of Quercus serrata, which started growing after the FDNPP accident, did not show radioactivity, indicating that significant amounts of translocation from other parts to new leaves did not occur. Fallen leaves of Q. serrata collected from a litter showed hot spots originating from direct fallout. Needles of Pinus densiflora were also contaminated by fallout. Leaching with pure water removed soluble fractions of radiocesium and hot particles from the surface of the contaminated leaves, but significant amounts of radioactivity remained. This means that foliar absorption occurred in both fresh and dead leaves. Further leaching experiments using surfactant and acetone could not remove the remaining radiocesium from the leaves. The leaching experiments indicate that radiocesium in the contaminated leaves is strongly fixed in leaf tissues and is not readily released unless leaf tissues are decomposed. 相似文献
108.
Shiro Matsumoto Yasuyuki Sugiyama Seizou Sakata Takayoshi Hayashi 《Liquid crystals》2013,40(5):649-655
Polymers containing droplets of liquid crystal smaller than 100 nm, which have good transparency and easily form films, were prepared under various conditions to evaluate their potential as electro-optic materials for waveguide-type devices. By varying the liquid crystal concentration and the strength of the UV irradiation causing photo-induced phase separation of the droplets, we were able to control the droplet size and density. We have clarified how the birefringence generated in an applied electric field, switching speed, and optical loss of light propagating in the film depend on droplet size and density. Polymer materials having a large electro-optic effect (δn = 0.001 at 8 V μm-1), low propagation loss (~2.5 dB cm-1), and fast response time (~10 μs) have been developed. 相似文献
109.
Ken-Ichi Kanno Yuichi Kobayashi Shin-Ichiro Nishimura Hiroyoshi Kuzuhara Kenichi Hatanaka 《Journal of carbohydrate chemistry》2013,32(4-5):481-490
Abstract 1,6-Anhydro-2-deoxy-3,4-di-O-benzyl-2-phthalimido-β-d- glucopyranose (5) was synthesized from 1,6-anhydro-β-d-mannopyranose (1) in five steps. Compound 5 was polymerized under cationic conditions and selectively yielded glucosamine oligomers (degree of polymerization 5-7). Copolymerization of 5 with 1,6-anhydro-2,3,4-tri-O-benzyl-β-d-glucopyranose indicated the low reactivity of 5 with the active cation derived from 5. Deprotection of 2-deoxy-3,4-di-O-benzyl-2-phthalimido-(1→6)-β-d-glucopyranan (7) and N-acetylation gave 2-acetamido-2-deoxy-(1→6)-β-d-glucopyranan (9). 相似文献
110.
Tetsuya Kajimoto Yuichi Ishioka Takahiro Katoh 《Journal of carbohydrate chemistry》2013,32(8-9):469-495
p‐Dodecylbenzenethiol (1) and p‐octyloxybenzenethiol (2) were synthesized as new odorless benzenethiols. Moreover, preparation of novel 1‐thioglycosides using 1 and 2 as well as their application for glycosylation reactions was performed. As a result, it was found that these 1‐thio‐glycosides were excellent glycosyl donors, and especially 2‐thio‐sialoside prepared from 1 and 2 afforded the best result to date in terms of α‐ and β‐selectivity in the sialylation where only the single C‐3 hydroxyl group of acceptor D‐galactopyranoside was free. All procedures from the preparation of thioglycosides to glycosylation reaction were attainable under completely odorless conditions. 相似文献