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41.
An improved method for constructing a full-length enriched cDNA library using small amounts of total RNA as a starting material 总被引:1,自引:0,他引:1
We have developed an improved method for constructing a full-length cDNA library using small quantity of material by modifying the original oligo-capping method. In our devised method, total RNAs are used in sequential oligo-capping steps directly without preliminary mRNA purification. Using this method, we constructed full- length cDNA libraries from 100 mg of total RNA. These libraries contained 8x10(5) to 8x10(6) independent clones with average insert sizes of 2.0 kb. Moreover, the number of full-length cDNAs containing the translation initiation codon ATG in the constructed libraries was estimated to 60-70%. In addition, 54% of the known cDNAs had a longer 5' end than the corresponding genes in the public database. Our results show that the method can be effectively used to construct full-length enriched cDNA libraries, especially, if starting material is limited. 相似文献
42.
Ming Guo Jue Wang Man Xiong Ronghui Wu Xuejuan Yang Jianzhong Zhou Minghui Li Jiajun Li 《大学化学》1986,35(12):237-246
In order to improve university laboratory teaching and practical education under the background of information technology, as well as overcome the difficulty for practical training, develop a virtual simulation experiment platform for rapid pyrolysis of natal materials and high-performance liquid chromatographic (HPLC) detection of its components. The experiment integrates the actual operation process of the plant to produce cleaved products by rapid pyrolysis of biomass with HPLC detection. The virtual experiment is divided into biomass sample pretreatment, rapid biomass pyrolysis, bio-oil extraction, and HPLC determination of complex components, making the biomass cleavage workshop "real" through simulation. This virtual simulation experiment fully integrates the utilization of biomass resources and basic chemistry courses (such as organic chemistry, instrumental analysis, chemical engineering principles, etc.), which are widely involved in agricultural and forestry majors with advantageous characteristics value. 相似文献
43.
A synthesis of a-acyloxyamides is described which utilizes the reaction of 7-picoline N-oxide and various organic acids with diphenylketene N-p-tolylimine. 相似文献
44.
Low molecular weight liquid rubber (ATBN = amine terminated butadiene acrylonitrile copolymer or CTBN = carboxyl terminated butadiene acrylonitrile copolymer)–DGEBA (diglycidyl ether of bisphenol A) blends indicated upper critical solution temperature (UCST) behavior. The phase separation behavior of the neat and crosslinked rubber (ATBN, CTBN)–epoxy blends was analyzed by a laser light scattering experiment. Lauryl peroxide (LPO) was employed to crosslink the rubber during the initial annealing stage. The onset point of the phase separation in the crosslinked ATBN–epoxy system occurred later than in the case of the neat ATBN–epoxy system. However, the onset point of the phase separation process started earlier in the case of the crosslinked CTBN–epoxy system. The domain correlation length of the crosslinked rubber-added system was smaller than that of the neat rubber-added system. 相似文献
45.
Monwar M Oh SJ Rinaldi PL McCord EF Hutchinson RA Buback MM Latz H 《Analytical and bioanalytical chemistry》2004,378(6):1414-1427
Poly(n-butylacrylate-co-carbon monoxide-co-ethylene) (polyEBC) samples prepared from 13C-labeled monomer, n-butyl acrylate, were characterized using two dimensional (2D) pulsed field gradient (PFG) 750 MHz NMR spectroscopy. To elucidate the complex structure of the terpolymer, 2D-1H/13C-heteronuclear single quantum coherence (HSQC) and heteronuclear multiple bond correlation (HMBC) experiments were conducted by selectively exciting the enhanced resonances in the spectra of two polymer samples, one polymer resulting from synthesis with 1-13C-n-butylacrylate monomer and a second polymer obtained from a synthesis with 2-13C-n-butylacrylate monomer. High-resolution 2D-NMR combined with 13C-labeling of the polymer greatly simplifies the 2D-NMR spectra, selectively enhances the weak peaks from low occurrence B-centered triad structures, and aids in their resonance assignments. In all experiments, the sample temperature was 120 degrees C, to ensure a homogeneous solution and sufficient molecular mobility. Electronic Supplementary Material: Supplementary material (1D 13C NMR spectra of the 13C-labeled and unlabeled polymers) is available in the online version of this article at http://dx.doi.org/100.1007/s00216-003-2402-3. 相似文献
46.
Orbital interaction analysis is employed to understand the complex charge transfer mechanism operative in endohedral metallofullerenes of composition NSc3@Cn (n = 68, 78). This phenomenon combines substantial electron transfer from the core to the cage with electron backdonation, involving the interaction between the occupied orbitals of the negatively charged cage and the unoccupied d orbitals of the positively charged core. This electron backdonation differs fundamentally from conventional orbital hybridization, which takes place primarily between the HOMO of the metal core and the LUMO of the fullerene cage. These findings imply the pronounced stability of NSc3@Cn (n = 68, 78), especially for NSc3 encapsulated in the non-IPR C68 enclosure, as experimentally established. 相似文献
47.
Li Yan Liang Shao Ping Ren Yi Quan Zheng Man Geng Lu Guangzhou Institute of Chemistry Chinese Academy of Sciences Guangzhou China Key Laboratory of Polymer Materials for Electronics Guangdong China Graduate School of the Chinese Academy of Sciences Beijing China 《中国化学快报》2007,18(2):225-228
A series of novel liquid crystalline epoxides with lateral substituents were cured with anhydrides and the cure kinetics was investigated by non-isothermal DSC technique. The results showed that the lengths of lateral substituents have great effect on the value of Ea. The curing reaction became less active, when the liquid crystalline epoxides have long lateral substituents and were controlled by diffusion at the late stage of cure. A nematic structure was observed by POM and XRD. 相似文献
48.
Key aspects of the microenvironment surrounding the Fe center in the nitrosyl adduct of iron phthalocyanine, [Fe(Pc)(NO)], have been elucidated from the analysis of the Fe K-edge extended X-ray absorption fine structure (EXAFS) of the material adsorbed on the surface of a high area carbon electrode recorded in situ, in 0.5 M H(2)SO(4). Statistical best fits to the EXAFS data place the Fe center in a five-coordinated square pyramidal configuration shifted away from the Pc plane toward the axially bound NO bent at an angle of ca. 40 degrees with respect to the normal to the Pc plane. This environment is analogous to that of Fe in the nitrosyl adduct of crystalline [Fe(TPP)], where TPP = meso-tetraphenylporphyrinato(2-), determined from X-ray diffraction. 相似文献
49.
The NagR protein is a response regulatory protein found in the bacterium Ralstonia sp. U2 that is involved in sensing for salicylic acid and the subsequent induction of the operaon just upstream of its gene.
The genes encoded for in this operon are involved in the degradation of salicylic acid. Escherichia coli strain RFM443 carrying a fusion of the Photorhabdus luminesscens luxCDABE operon with the nagR gene and upstream region of the nagAa gene was constructed and characterized with respect to its optimum temperature, its response time and kinetics, and its ability
to deterctnumerous benzoic acid derivatives. Although capable of detecting 0.5 mM salicylic acid at any temperature between 28 and 40°C, this E. coli strain, labeled DNT5, showed its greatest relative activity at 30°C, i.e., the temperature at which the largest induction
was seen. Furthermore, experiments done with numerous benzoic acid derivatives found the NagR protein to be responsive to
only a few of the compounds tested, including salicylic acid and 3-methyl salicylic acid and 3-methyl saliyclic acid, and
acetyl salicylic acid was the strongest inducer. The lower limits of detection for these compounds with E. coli strain DNT5 were also established, wit the native inducer, salicylic acid, giving the most sensitive response and detectable
down to a concentration of about 2 μM. A second lux fusion plasmid was also constructed and transformed into an NahR background, Pseudomonas putida KCTC1768. Within this strain, NAGK-1768, the supplemental activity of the NahR protein on the nagAn promoter, was shown to extend both the range of chemicals detected and the sensitivity. 相似文献
50.
Sung Woo Moon Gun-Dae Lee Seong Soo Park Seong-Soo Hong 《Reaction Kinetics and Catalysis Letters》2004,82(2):303-310
Catalytic combustion of chlorobenzene over supported vanadium oxides has been investigated. TiO2 was prepared by the sol-gel method from titanium isopropoxide. The supported vanadium oxide catalysts have been prepared
by precipitation-deposition and impregnation method and characterized by XRD, FT-Raman and TPR. In the VOx/TiO2catalysts prepared using the impregnation method, when vanadium loading reaches 3 wt.%, the activity shows a maximum. However,
in the VOx/TiO2catalysts prepared by precipitation-deposition, when vanadium loading reaches 7 wt.%, the activity shows a maximum. This result
suggests that the precipitation-deposition can yield a higher metal loading on the support and a high dispersion compared
to the impregnation method.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献