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1.
Two-dimensional map of Haemophilus influenzae following protein enrichment by heparin chromatography
M Fountoulakis H Langen S Evers C Gray B Takács 《Canadian Metallurgical Quarterly》1997,18(7):1193-1202
Two-dimensional gel electrophoresis separates several hundred protein molecules in one single experiment and is efficiently used to study the products expressed by different genomes. Low-copy-number gene products are invisible on a stained two-dimensional map and must be enriched such that sufficient amounts are present for visualization and identification. We investigated the enrichment of proteins of the bacterium Haemophilus influenzae by chromatography on immobilized heparin which has affinity for growth and protein biosynthesis factors. Total soluble proteins of the microorganism were fractionated on Heparin-Actigel which resulted in enrichment of approximately 160 proteins. The eluates, representing about 40% of the applied proteins, were analyzed by two-dimensional gel electrophoresis and the protein spots were characterized by amino acid composition analysis and matrix-assisted laser desorption ionization mass spectrometry. The proteins enriched by chromatography on the heparin gel were not exclusively low-copy-number gene products and they did not exclusively belong to one single class of proteins. The proteins that bound to the heparin gel are indicated in a two-dimensional protein map which includes more than 110 newly identified proteins. 相似文献
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Elasser A. Kheraluwala M.H. Ghezzo M. Steigerwald R.L. Evers N.A. Kretchmer J. Chow T.P. 《Industry Applications, IEEE Transactions on》2003,39(4):915-921
Recent progress in silicon carbide (SiC) material has made it feasible to build power devices of reasonable current density. This paper presents results including a comparison with state-of-the-art silicon diodes. Switching losses for two silicon diodes (a fast diode, 600 V, 50 A, 60 ns Trr), an ultrafast silicon diode (600 V, 50 A, 23 ns Trr), and a 4H-SiC diode (600 V, 50 A) are compared. The effect of diode reverse recovery on the turn-on losses of a fast insulated gate bipolar transistor (IGBT) are studied both at room temperature and at 150 /spl deg/C. At room temperature, SiC diodes allow a reduction of IGBT turn-on losses by 25% compared to ultrafast silicon diodes and by 70% compared to fast silicon diodes. At 150 /spl deg/C junction temperature, SiC diodes allow turn-on loss reductions of 35% and 85% compared to ultrafast and fast silicon diodes, respectively. The silicon and SiC diodes are used in a boost converter with the IGBT to assess the overall effect of SiC diodes on the converter characteristics. Efficiency measurements at light load (100 W) and full load (500 W) are reported. Although SiC diodes exhibit very low switching losses, their high conduction losses due to the high forward drop dominate the overall losses, hence reducing the overall efficiency. Since this is an ongoing development, it is expected that future prototypes will have improved forward characteristics. 相似文献
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Synthesis of Substituted 5-Amino-1,2,4-triazoles N-Nitro-amidino-dithiocarbimidic acid dimethylester 1 reacts with monosubstituted hydrazines under formation of the substituted 5-amino-1, 2, 4-triazoles. Disubstituted hydrazines give under the same conditions N-nitro-amidino-S-methyl-isothiosemicarbazides. The reaction of some more hydrazine derivatives with 1 yields the adequate substituted 1, 2, 4-triazoles. 相似文献
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Reactions with Thio-bis-formamidines N,N,N′-Trisubstituted S-(4-amino-s-triazin-2-yl)-isothioureas 3 are prepared in good yields form trisubstituted thio-bis-formamidine-hydrochlorides 1 and esters of cyanimidocarboxylic acids 2 . In aqueous alkali solutions compounds 1 react with β-dicarbonyl compounds under rearrangement to yield substituted N-(pyrimidin-2-yl)-thioureas 4 and 5 . 相似文献
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The incorporation of phase change materials (PCMs) in building materials for use as latent heat storage and for potential reduction of energy requirements is an on-going field of study. In this paper, the development and testing of PCM-enhanced cellulose insulation for use in frame walls is presented. Two types of PCMs, paraffin-based and hydrated salt-based, were mixed into loose-fill cellulose insulation at concentrations of 10% and 20% (by the weight of the wallboard) in a 1.22 m × 1.22 m (48 in. × 48 in.) frame wall cavity. The thermally-enhanced frame walls were heated and allowed to cool down in a dynamic wall simulator that replicated the sun's exposure in a wall of a building on a typical summer day. Peak heat fluxes, total “daily” heat flows, and surface and air temperatures were measured and recorded. Results show that the paraffin-based PCM-enhanced insulation reduced the average peak heat flux by up to 9.2% and reduced the average total “daily” heat flow up to 1.2%. Because of the hydroscopic behavior of un-encapsulated hydrated salt, the hydrated salt-based PCM-enhanced insulation did not provide any thermal storage benefit. 相似文献
7.
A rapid presence/absence test for Campylobacter in chicken faeces is being evaluated to support the scheduling of highly contaminated broiler flocks as a measure to reduce public health risks [Nauta, M. J., & Havelaar, A. H. (2008). Risk-based standards for Campylobacter in the broiler meat chain. Food Control, 19, 372–381]. Although the presence/absence test is still under development, an example data set of test results is analysed to illustrate the benefit of the detection probability concept. The detection probability of Campylobacter increases with the logarithm of the Campylobacter concentration in faeces according to an S-shaped curve which stretches about 2–3 log units. The detection probability is 50% at a Campylobacter concentration of 7.4 × 106 cfu/g. The uncertainty in the detection probability is 32% at the most for a 90% confidence interval. This type of information allows for realistic calculations on the Campylobacter status of different food processing paths after splitting. Usable quantitative estimates on detection probability await a data set of test results from a test that is ready for use or has similar properties. 相似文献
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We investigate QED field-dependent effects in radiative shifts of atomic levels driven by a strong laser field. Our focus is on indirect laser-induced corrections to the Lamb shift of an atomic reference state due to a strong laser field which near-resonantly couples two other states, but not the reference state. Our aim is to show how to generalize previous treatments of related scenarios to the case of an induced indirect coupling. We also derive an expression of self-energy corrections in the Floquet picture and analyse various coupling schemes with respect to the shift of Floquet quasi-energies. The semi-classical Floquet picture and the fully quantized dressed-state approach are contrasted. 相似文献
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Evers M. Tse-Yu Yeh 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》2001,89(11):1610-1620
Branch prediction is important in high-performance processors and its importance continues to grow. In the drive for higher execution frequencies, pipelines are lengthened and memory latencies are increased. This increases the cost of branch mispredictions. In this paper we describe some behavior patterns of branches. We believe that understanding the behavior of branches is helpful when designing fetch mechanisms for high-performance microprocessors. We also examine several current branch predictors and discuss how they work. Finally, we look at some of the challenges that we are faced with when designing fetch mechanisms and predictors for future microprocessors and discuss some of the possible solutions 相似文献