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81.
M Bouziane DI Cherny JF Mouscadet C Auclair 《Canadian Metallurgical Quarterly》1996,271(17):10359-10364
Integration of the human immunodeficiency virus (HIV) DNA into the host genome is an obligatory process in the replicative life cycle of the virus. This event is mediated in vitro by integrase, a viral protein which binds to specific sequences located on both extremities of the DNA long terminal repeats (LTRs). These sites are highly conserved in all HIV genomes and thus provide potential targets for the selective inhibition of integration. The integrase-binding site located on the HIV-1 U5 LTR end contains two adjacent purine tracts on opposite strands, 5' . . . GGAAAATCTCT-3'/3'-CCTTTTAGAGA . . . 5', in parallel orientations. A single strand oligonucleotide 5'-GGTTTTTGTGT-3' was designed to associate with these tracts via its ability to form a continuous alternate strand DNA triplex. Under neutral pH and physiological temperature, the oligonucleotide, tagged with an intercalator chromophore oxazolopyridocarbazole, formed a stable triplex with the target DNA. The occurrence of this unusual triplex was demonstrated by both DNase I footprinting and electron microscopy. The triplex inhibits the two steps of the integrase-mediated reactions, namely, the endonucleolytic cleavage of the dinucleotide 5'-GT-3' from the 3' end of the integration substrate and the integration of the substrate into the heterologous target DNA. The midpoints for both inhibition reactions were observed at oligonucleotide concentrations of 50-100 nM. We believe that these results open new possibilities for the specific targeting of viral DNA LTR ends with the view of inhibiting integration under physiological conditions. 相似文献
82.
When the cost of reducing the duration of activities is convex and nonlinear, it may be advisable (to reduce the computing burden) to seek a “satisficing” answer, in which the project is compressed to a desired completion time with a prespecified tolerable relative error. We treat the problem of constructing the optimal first degree interpolating linear spline that guarantees such maximal error and consider various possible refinements. 相似文献
83.
X-ray diffraction analysis was utilized to investigate the mineralogical composition of red bricks as affected by the used raw materials. The data indicate that the bricks are composed of spinel, hematite, cristobalite, feldspars and quartz. The relative abundance of each of these minerals depends on the nature of the raw materials. Bricks made out of bentonite sediments contain more quar-tz and less feldspars compared with those made out of soil materials. It is suggested that the intensity ratio of quartz reflection at 3.34 Å to that of feldspars at 3.2 Å may be used to distinguish between bentonitic red bricks from those made out of soil materials. Therefore, the law which forbids using soil materials for brickmaking can be implemented on sound legal and technical grounds. 相似文献
84.
A theoretical method for the prediction of fatigue life of structural members containing external stress raisers has been developed. The method is based on a linear elastic fracture mechanics approach to fatigue. The theory has been applied to fatigue of Torbar steel in concrete beams. The required parameters for such application were obtained from fatigue tests on samples and finite element analysis of cracked bars. Comparisons between the theory and experimental data taken from other investigations have shown that the theory predicts a reasonable lower limit fatigue life of Torbar in concrete beams. The theory has also successfully predicted the effect of the minimum stress on the fatigue life of this type of bar. 相似文献
85.
Fluorescence spectroscopy coupled with factorial discriminant analysis technique to identify sheep milk from different feeding systems 总被引:1,自引:0,他引:1
Moncef Hammami Hamadi Rouissi Nizar Salah Houcine Selmi Mutlag Al-Otaibi Christophe Blecker Romdhane Karoui 《Food chemistry》2010
Rapid measurements of milk properties and discrimination of milk origin are necessary techniques for quality control of milk products. The present study was undertaken to evaluate the potential of using front face fluorescence spectroscopy (FFFS) and synchronous fluorescence spectroscopy (SFS) for monitoring the quality of forty-five ewe’s milk samples originating from different feeding systems. Physico-chemical analyses and fluorescence spectra were conducted on samples during lactation periods (the first 11 weeks). The principal component analysis (PCA) separately applied to the physico-chemical and fluorescence spectral data showed only small discrimination between milk samples based on lactation periods and diet compositions. Similar results were obtained by separately applying factorial discriminant analysis (FDA) on each technique. In a second step, concatenation technique were applied to FFF spectra acquired after excitation set at 250, 290, 380 nm and emission set at 410 nm. Results obtained showed a good discrimination among milk samples with regard to feeding systems given to the ewes throughout the lactation periods. In addition, a better discrimination was observed with FFFS than with SFS. 相似文献
86.
Salah Abdulrhmann Minoru Yamada Moustafa Ahmed 《International Journal of Numerical Modelling》2011,24(3):218-229
Influence of the linewidth‐enhancement factor on the output and operations of InGaAs/InP pumping lasers emitting at a wavelength of 980 nm under strong optical feedback is investigated numerically. The investigations are performed based on intensive numerical integration of an improved time‐delay rate equations of semiconductor lasers over wide ranges of the linewidth‐enhancement factor and optical feedback strength. The results show that the semiconductor laser operates under strong optical feedback in continuous wave and pulsation at small values of the linewidth‐enhancement factor. Under large values of the linewidth‐enhancement factor, the laser happens to exhibit chaos and pulsation. We predict that semiconductor laser subjected to strong optical feedback exhibits much more stable pulsing operation under higher values of the linewidth‐enhancement factor, which indicates that the laser is locked at the external cavity frequency. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
87.
Shahira Said Aly Tsuyoshi Imai Mohamed Salah Hassouna Diem-Mai Kim Nguyen Takaya Higuchi Ariyo Kanno Koichi Yamamoto Rinji Akada Masahiko Sekine 《International Journal of Hydrogen Energy》2018,43(10):5300-5313
The ability of Clostridium butyricum RAK25832 to use casamino acids as a nitrogen source was investigated. Strain RAK25832 showed the capacity to utilize different types of carbon sources. With glucose as a carbon source (10 g/L), the preferred final concentration of casamino acids was 26.67 g/L, with a cumulative hydrogen production, production rate, and yield of 2505 mL H2/L, 160 mL/h, and 1.81 mol H2/mol glucose, respectively. Eighteen metal elements were screened to identify the most important metals for biohydrogen production, and four elements were optimized. The optimal medium composition was MgCl2·6H2O (0.1 g/L), K2HPO4·3H2O (6.67 g/L), NaHCO3 (2.6 g/L), and FeCl2·4H2O (0.002 g/L). Vitamin supplementation of the medium showed no significant effect on hydrogen production. Under the optimized conditions, cumulative hydrogen production reached 3074 mL H2/L. This is the first study to demonstrate the use of casamino acids as a nitrogen source by C. butyricum. 相似文献
88.
89.
Alameda-Pineda Xavier Ricci Elisa Salah Albert Ali Sebe Nicu Yan Shuicheng 《International Journal of Computer Vision》2020,128(5):1376-1377
International Journal of Computer Vision - 相似文献
90.
Taj M. Khan Shahab Ud-Din Khan Salah Ud-Din Khan Ashfaq Ahmad Shahab Ahmed Abbasi Eid Muhammad Khan Sam Mehigan 《国际能源研究杂志》2020,44(14):11443-11452
For the fast uptake into industrial applications, the further development of robust methods of nanomaterials, which are inexpensive and simultaneously technologically feasible, is one of the major key factors. A newly introduced atmospheric pulsed laser deposition method, based on a flowing gas approach, was used for plasmonic metal nanoparticle (NP) film of silver. Contrary to vacuum, in this method, the ambient air restricts expansion of the ablation plume within 1 to 3 mm above the target surface. These sets constrain on the formation of NP film close to the ablation spot. For deposition on a widely spaced surface, ablation material was entrained in a flow of argon, supplied at ~32 ms−1, and effectively delivered to the substrate at ~20 ms−1. The films produced were crystalline and particulate in nature, showing spectral plasmonic feature of surface plasmon resonance in the visible region. The film was directly tested in surface-enhanced Raman spectroscopy for chemical detection of crystal violet; the film with large particulates and aggregated crystallites was well-performed, showing enhanced Raman signals and detection sensitivity. Certainly, flowing gas atmospheric pulsed laser deposition seems a fast alternative to vacuum-pulsed laser deposition but needs further investigations to bring it in the industry for applications in sensor, catalysis, solar cell, and coating technology. 相似文献