corynebacterium glutamicum is the major workhorse for the microbial production of several amino and organic acids. As long as these derive from tricarboxylic acid cycle intermediates, the activity of anaplerotic react...
详细信息
corynebacterium glutamicum is the major workhorse for the microbial production of several amino and organic acids. As long as these derive from tricarboxylic acid cycle intermediates, the activity of anaplerotic reactions is pivotal for a high biosynthetic yield. To determine single anaplerotic activities c-13-Metabolic Flux Analysis (c-13-MFA) has been extensively used for c. glutamicum, however with different network topologies, inconsistent or poorly determined anaplerotic reaction rates. Therefore, in this study we set out to investigate whether a focused isotopomer model of the anaplerotic node can at all admit a unique solution for all fluxes. By analyzing different scenarios of active anaplerotic reactions, we show in full generality that for c. glutamicum only certain anaplerotic deletion mutants allow to uniquely determine the anaplerotic fluxes from c-13-isotopomer data. We stress that the result of this analysis for different assumptions on active enzymes is directly transferable to other compartment-free organisms. Our results demonstrate that there exist biologically relevant metabolic network topologies for which the flux distribution cannot be inferred by classical c-13-MFA. Biotechnol. Bioeng. 2016;113: 661-674. (c) 2015 Wiley Periodicals, Inc.
Protein kinase c (PKc) has a crucial role in signal transduction for a variety of biologically active substances which activate cellular functions and proliferation. We previously isolated the full-length PKc gene fro...
详细信息
Protein kinase c (PKc) has a crucial role in signal transduction for a variety of biologically active substances which activate cellular functions and proliferation. We previously isolated the full-length PKc gene from Dunaliella salina (DsPKc) using rapid amplification of cDNA ends (RAcE) and RT-PcR methods. And we submitted the mRNA sequence of DsPKc gene to NcBI (Genbank No. JN625213). In the present paper, the DsPKc gene open reading frame obtained by PcR was cloned into pGS-21a vector and transformed into Escherichia coli to generate the fusion protein. Bioinformatics analysis revealed that DsPKc gene was a member of serine/threonine kinase with two conserved domains and highly conserved motifs. The DsPKc was highly expressed upon induction with isopropyl-β-d-thiogalactoside (IPTG) at a final concentration of 0.2 mmol L 1 at 37℃. Under salt stress, the fu- sion protein Green Fluorescent Protein (GFP)-DsPKc was transferred from the cytoplasm to the cell membrane. The expression pat- tern of DsPKc gene was analyzed using real-time quantitative PcR, and indicated that DsPKc gene was up-regulated by 3.0 mol L 1 Nacl at 12 h, which was significantly higher than in control values (P < 0.05). These results suggest that the DsPKc gene plays an important role in response to salt stress in D. salina.
The surface layer and elemental composition of a lithium-metal electrode before and after in contact with nanocomposite polymer electrolytes (NcPEs) comprising poly(ethylene oxide)/ca3(PO4)2/LiX (X = N(cF3SO2)2, clO4)...
详细信息
The surface layer and elemental composition of a lithium-metal electrode before and after in contact with nanocomposite polymer electrolytes (NcPEs) comprising poly(ethylene oxide)/ca3(PO4)2/LiX (X = N(cF3SO2)2, clO4) were analyzed by X-ray photoelectron spectroscopy. The presence of Li2cO3/LiOH in the outer layer of the native film was identified. The formation of LiF was detected on lithium surface when in contact with NcPE containing LiN(cF3SO2)2 and is attributed to the reaction between the native film and impurities. Li/NcPE/Li symmetriccells were assembled, and the thickness of the solid electrolyte interface as a function of time was analyzed at 60 degrees c. (c) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Superior electrode materials play a key role on the electrochemical performance for the lithium-ion batteries and supercapacitors. The co3O4-based materials are promising electrode materials due to their high specific...
详细信息
Superior electrode materials play a key role on the electrochemical performance for the lithium-ion batteries and supercapacitors. The co3O4-based materials are promising electrode materials due to their high specificcapacity and energy density. However, the poor cycle performance limits their applications during the process of the commercialization for the lithium-ion batteries and supercapacitors. Because of the poor cycle stability, c, N co-doped co3O4 hollow spheres are successfully prepared and used as electrode materials for the lithium-ion batteries and supercapacitors. Via the c, N co-doping process, the electronicconductivity is greatly improved. Moreover, the hollow structure could ensure the structural stability during the electrochemical process. As a result, the cycle performance and specificcapacity are greatly improved when the c, N co-doped co3O4 composites are used as electrode materials for the lithium-ion batteries and supercapacitors. (c) 2019 Hydrogen Energy Publications LLc. Published by Elsevier Ltd. All rights reserved.
A one-pot synthesis of substituted (dihydro)thieno[2,3-c]chromene derivatives was developed through a Lewis base catalyzed domino Michael addition/intramolecular cyclization reaction between 3-nitro-2H -chromenes and ...
详细信息
A one-pot synthesis of substituted (dihydro)thieno[2,3-c]chromene derivatives was developed through a Lewis base catalyzed domino Michael addition/intramolecular cyclization reaction between 3-nitro-2H -chromenes and thioamides. The desired (dihydro)thieno[2,3-c]chromene derivatives were prepared with a large substrate scope (22 examples) and excellent diastereoselectivity in moderate to excellent yields.
Backtrack programming is such a powerful technique for problem solving that a number of languages, especially in the area of artificial intelligence, have built-in facilities for backtrack programming. This paper desc...
详细信息
Backtrack programming is such a powerful technique for problem solving that a number of languages, especially in the area of artificial intelligence, have built-in facilities for backtrack programming. This paper describes cBack, a simple, but general tool for backtrack programming in the programming language c. The use of the tool is illustrated through examples of a tutorial nature. In addition to the usual depth-first search strategy, cBack provides for the more general heuristic best-first search strategy. The implementation of cBack is described in detail. The source code, shown in its full length, is entirely written in ANSI c and highly portable across diverse computer architectures and ccompilers.
Three novel curcuminoids, curcumaromins A-c (1-3, resp.), along with a known compound, longiferone B (4) were isolated from curcuma aromatica SALISB. The structures of the new compounds were elucidated as (1E,4Z,6E)-5...
详细信息
Three novel curcuminoids, curcumaromins A-c (1-3, resp.), along with a known compound, longiferone B (4) were isolated from curcuma aromatica SALISB. The structures of the new compounds were elucidated as (1E,4Z,6E)-5-hydroxy-7-{4-hydroxy-3-[(1R*,6R*)-3-methyl-6-(propan-2-yl) cyclohex- 2-en-1-yl) phenyl}-1-(4-hydroxyphenyl)hepta-1,4,6-trien-3-one (1), 2,3-dihydro-2-(4-hydroxyphenyl)- 6-[(E)-2-(4-hydroxyphenyl) ethenyl]-5-[(1R*, 6R*)-3-methyl-6-(propan-2-yl) cyclohex-2-en-1-yl]-4Hpyran- 4-one (2), and (1E, 6E)-1,7-bis(4-hydroxyphenyl)-4-[(1R*, 6R*)-3-methyl-6-(propan-2-yl) cyclohex- 2-en-1-yl] hepta-1,6-diene-3,5-dione (3) on the basis of spectroscopic analysis. curcumaromins A-c (1-3) represented the first examples of menthane monoterpene-coupled curcuminoids. The known compound, longiferone B (4), was the first daucane sesquiterpene isolated from the genus curcuma.
An investigation was carried out on the reaction process and mechanism between K 2TiF 6, graphite powder and aluminum melt with the common Ti concentration of 5%～7% in the grain refiner Al Ti c master alloys and the ...
详细信息
An investigation was carried out on the reaction process and mechanism between K 2TiF 6, graphite powder and aluminum melt with the common Ti concentration of 5%～7% in the grain refiner Al Ti c master alloys and the reaction temperature of 750～950 ℃, aiming at understanding their reaction mechanism and putting forward the aluminothermal reduction reaction method to practical use. During experimental investigation, K 2TiF 6 and graphite wrapped in aluminum foils were introduced into the aluminum melt at 850 ℃. Samples of alloy and slag were investigated by chemical analysis, XRD examination, SEM observation, and EDS analysis as well. It was found that the reaction was very vigorous at the beginning of the process and then reached a dynamic equilibrium. There were 3 particular reactions during the aluminothermal reaction process. At the beginning stage of the reaction, there emerged the phases of Tic and one type of metastable intermetallic phase TiAl 9 as well as TiAl 3 in aluminum melt. At the late stage of the reaction, the metastable phase TiAl 9 disappeared and another phase of Al 4c 3 emerged.
The designs of sealing device have prominent influence on the performance of aero-engine. The high temperature environment during the working process of aero-engine also has important influence on the performance of s...
详细信息
The designs of sealing device have prominent influence on the performance of aero-engine. The high temperature environment during the working process of aero-engine also has important influence on the performance of sealing device which is located in the aero-engine. Finger seal has a flexible characteristic and high price performance compared with the other seal devices, thus it gets more attention, and lots of researchers have studied about finger seal's performance recently. But so far the dynamic performance of finger seal considering temperature effect is not yet analyzed and discussed. Based on this, an equivalent dynamic model based on distributed mass considering temperature effect is proposed in the paper. The effects of environment temperature and heat through friction on the equivalent structural stiffness of finger stick and contact pressure between finger stick and rotor are discussed. Moreover, the data exchange between the dynamic and thermal analysis is confirmed based on the movement relationship between the rotor excitation and finger stick response. Therefore, the dynamic performance analysis of finger seal including thermal-structure coupling is obtained based on an equivalent dynamic method. The effect of temperature on the dynamic performance of finger seal using this model is analyzed, and the effect of c/ccomposite structural parameters on the finger seal performance is investigated considering the temperature effect. The above results show that the temperature effect has important influence on the performance of finger seal, so it is necessary to consider the temperature effect when the performance of finger seal is analyzed. The current work further improves the theoretical system about finger seal equivalent dynamic research, and has higher academic significance and engineering value.
The physical properties and device electrical properties of superlattice-like c/Sb phase change films are investigated. compared with Sb monolayer films, the superlattice-like c/Sb films have preferable thermal stabil...
详细信息
The physical properties and device electrical properties of superlattice-like c/Sb phase change films are investigated. compared with Sb monolayer films, the superlattice-like c/Sb films have preferable thermal stability, including higher crystallization temperature, longer data life, and larger crystallization activation energy. As the thickness of the carbon layer increases, the band gap gradually increases. X-ray photoelectron spectroscopy results show that c-Sb bonds exist in the c/Sb superlattice-like films. X-ray diffraction and atomic force microscope results show that the addition of carbon inhibits the grain growth, making the grain size smaller and inhibiting the crystallization of Sb materials. Phase-change memory devices based on [c(6nm)/Sb(4nm)](8) superlattice-like films have smaller threshold voltages and lower power consumption compared to Sb films. In conclusion, c/Sb superlattice-like films have high thermal stability and low power consumption.
暂无评论