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排序方式: 共有162条查询结果,搜索用时 15 毫秒
11.
Kuzuya A Mizoguchi R Morisawa F Komiyama M 《Chemical communications (Cambridge, England)》2003,(6):770-771
Short RNA fragments containing single nucleotide polymorphism (SNP) sites have been selectively clipped out of substrate RNA by using complementary DNA having two acridine residues and Lu(III), and the genotype of the substrate is accurately and easily determined by mass analysis of these fragments. 相似文献
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14.
Fumi Shozui 《Polymer Degradation and Stability》2010,95(8):1340-217
New lactate (LA)-based terpolymers, P[LA-co-3-hydroxybutyrate (3HB)-co-3-hydroxyhexananoate (3HHx)]s, were produced in recombinant Escherichia coli LS5218 harboring three genes encoding LA-polymerizing enzyme (LPE), propionyl-coenzyme A (CoA) transferase (PCT) and (R)-specific enoyl-CoA hydratase (PhaJ4). When the recombinant LS5218 was grown on glucose with the feeding of butyrate, 3HB-CoA and 3HHx-CoA were supplied, probably via reverse reactions of the β-oxidation pathway and PhaJ4. LPE copolymerized the two monomers 3HB-CoA and 3HHx-CoA with LA-CoA, which was generated by PCT, to yield the terpolymers. Gas chromatography analysis revealed that the terpolymers consisted of 2.7-34 mol% LA, 38-81 mol% 3HB and 17-33 mol% 3HHx units, which can be varied depending on the butyrate concentration fed in the medium. In addition, 1H-13C COSY NMR analysis provided evidence for a linkage between LA and 3HHx units in the polymer. 相似文献
15.
We synthesized the DNA oligonucleotide containing a new cross-linkable 4-amino-2-oxo-6-vinyltriazine (AOVT) nucleobase analogue (Et-AOVT) and evaluated these properties. Our results of the cross-link assay and thermal denaturing assay of duplexes containing AOVT demonstrated that the additional aza of AOVT has an impact on the duplex stability and crosslink properties. Our data suggests that the additional 5-aza of AOVT is involved in the hydrogen bonding with the complementary guanine, and this hydrogen bonding system successfully flipped the reactive vinyl group out to the major groove of the duplex demonstrating a new paradigm of a “cross-linkable duplex”. 相似文献
16.
The passages of vapor flow and the returning liquid flow, are perfectly partitioned in a separate thermosyphon. Therefore the flooding limit can be eliminated, and practicability based on its construction is highly evaluated. In the present work, a container tube made of heat resisting glass, in which an electric heater is inserted, is selected as the heating section of the experimental equipment. Distilled water is used as the working fluid. The influence of the heater type, the diameter of evaporating section and the liquid fill charge on the heat transfer performance have been studied. The larger heat transfer coefficient is achieved in the case of the U type heater, the larger tube diameter and the less liquid fill charge of the evaporating section. The useful correlation equations of the heat transfer coefficient in the evaporator have been derived.
Experimentelle Untersuchung an einem Trennstrom-Thermosiphon
Zusammenfassung In einem Trennstrom-Thermosiphon sind die Strömungskanäle für die Dampfströmung und den Kondensatrücklauf vollkommen separiert. Die Flutgrenze kann deshalb unberücksichtigt bleiben. In dieser Untersuchung dient ein temperaturbeständiges Glasrohr mit innenliegender Heizung als Wärmequelle. Arbeitsmedium ist destilliertes Wasser. Untersucht wurden der Einfluß des Heizelementtyps, des Durchmessers der Verdampferstrecke und der Füllmenge auf das Wärmeüber-gangsverhalten. Das U-Typ Heizelement liefert bei größerem Rohrdurchmesser und geringerer Füllmenge in der Verdampferstrecke die höchsten Wärmeübergangskoeffizienten. Für diese wurden Korrelationsgleichungen aufgestellt.相似文献
17.
Fumi ShozuiKen’ichiro Matsumoto Ren MotohashiJian Sun Toshifumi SatohToyoji Kakuchi Seiichi Taguchi 《Polymer Degradation and Stability》2011,96(4):499-504
A poly(lactic acid) (PLA)-like terpolyester consisting of 96 mol% lactate (LA), 1 mol% 3-hydroxybutyrate and 3 mol% 3-hydroxyvalerate was produced in recombinant Escherichia coli LS5218 expressing LA-polymerizing enzyme (LPE). The strain was grown on glucose with a feeding of valerate as the monomer precursor. The glass transition and melting temperatures of the terpolyester were close to those of chemically synthesized poly(L-LA)s (PLLAs) having similar molecular weights. Additionally, a blend of the terpolyester, which was composed entirely of (R)-LA (D-LA) due to the strict enantiospecificity of LPE, with PLLA formed a stereocomplex with higher melting temperature (201.9 °C). These results indicate that the biological PLA-like polyester produced via this one-step microbial process has comparable thermal properties to chemically synthesized PLAs. 相似文献
18.
A. Venkateswara Rao Uzma K. H. Bangi Sunetra L. Dhere Hiroaki Imai Hiroshi Hirashima 《Journal of Sol-Gel Science and Technology》2011,57(1):95-100
The effect of iron acetylacetonate on the physico-chemical properties of waterglass based silica aerogels by ambient pressure
drying has been investigated. Doping the gels with iron acetylacetonat (FeAA) facilitates in the diminution of the density
of the aerogels. The well established silica network provides effective confinement of FeAA nanoparticles which resists the
collapse of silica network during ambient pressure drying. Therefore, in the present paper, the effects of FeAA on the physico-chemical
properties of the aerogels have been studied by varying the FeAA:Na2SiO3 molar ratio from 3 × 10−4 to 6 × 10−4. The aerogels were prepared via ambient pressure drying and characterized by the bulk density, thermal conductivity and water
contact angle. The aerogel’s surface morphology, elemental analysis and pore structure were characterized by means of EDAX
and FTIR, TEM and N2 adsorption- desorption analyzer. The high temperature hydrophobicity of these aerogels was checked by heating them in temperature
controlled furnace. Silica aerogels with low density ~0.050 g/cc have been obtained using the molar ratio of Na2SiO3:H2O:FeAA:Citric acid:TMCS at 1:146.67:3 × 10−4:0.54:9.46, respectively. EDAX and FTIR studies show that the iron species are entrapped in the mesoporous framework and not
took part in the bonding with silica. 相似文献
19.
Eiichi Masumoto Hiroshi Maruoka Fumi Okabe Sho Nishida Yuki Yoshimura Toshihiro Fujioka Kenji Yamagata 《Journal of heterocyclic chemistry》2011,48(1):96-104
Dihydropyridazinones 4a , 4b , N‐substituted dihydropyrazoles 5b , 5c , 5d , and O‐substituted pyrazoles 6a , 6b , 6c , 6d have been synthesized starting from spirocyclopropanepyrazole derivative 2 . Treatment of 2 with α‐chloro esters, e.g., methyl chloroacetate, ethyl chloroacetate, isopropyl chloroacetate, and tert‐butyl chloroacetate, in potassium carbonate/sodium iodide system caused ring opening and subsequent C‐ or N‐attack nucleophilic substitution to give the corresponding dihydropyridazinones 4a , 4b and N‐substituted dihydropyrazoles 5b , 5c , 5d . On the other hand, in the absence of sodium iodide, O‐substituted pyrazoles 6a , 6b , 6c , 6d were obtained from 2 via an O‐attack nucleophilic substitution. J. Heterocyclic Chem., 2011. 相似文献
20.
Yoshiharu Matsubara Toshikazu Uchida Takashi Ohnishi Koichi Kanehira Yoshiji Fujita Tsuneaki Hirashima Ikuzo Nishiguchi 《Tetrahedron letters》1985,26(37):4513-4516
Anodic oxidation in acetic acid of polycyclic cyclopropanes, namely tricyclene, cyclofenchene, and longicyclene, followed by hydrolysis brought about stereo- and regioselective formation of the corresponding homoallylic alcohols as the main product in good yields. 相似文献