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41.
Laurent François Joël Dupays Dmitry Davidenko Marc Massot 《Combustion Theory and Modelling》2020,24(5):775-809
We investigate a model of solid propellant combustion involving surface pyrolysis coupled to finite activation energy gas-phase combustion. Existence and uniqueness of a travelling wave solution are established by extending dynamical system tools classically used for premixed flames, dealing with the additional difficulty arising from the surface regression and pyrolysis. An efficient shooting method allows to solve the problem in phase space without resorting to space discretisation nor fixed-point Newton iterations. The results are compared to solutions from a CFD code developed at ONERA, assessing the efficiency and potential of the method, and the impact of the modelling assumptions is evaluated through parametric studies. 相似文献
42.
Byoung-Kee Jo Hyun-Don Kim Chun-Hag Jang Ki-Won Song Jang-Oo Lee 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(11):2293-2310
Abstract Interpolymer complex formation between basic polypeptides, poly(L- proline) Form I [PLP(I)], Form II [PLP(II)] and poly-4-hydroxy-L-proline (PHLP), and acidic polypeptides, poly(L-glutamic acid) (PLGA), poly(D- glutamic acid) (PDGA) and poly(L-aspartic acid) (PLAA), has been studied in water-methanol (1:2 v/v) mixed-solvent by viscometry, potentiometry, light scattering and circular dichroism (CD) measurements. It has been found that polymer complexes between basic- and acidic- polypeptides are formed via hydrogen bonding with a stoichiometric ratio of basic/acidic polypeptides =1:2 (in unit mole ratio) and that PLP(II) forms polymer complex more favorably with PLGA than with PLAA, and the complex of PLP(II) with PLGA is also more favorable than the complex formation of PHLP with PLGA. In addition, the complex formation is highly dependent on the conformation, especially the optical structure of the component polymers, i.e., the stereoselective complexation is observed. The PLGA having a right-handed helix at pH 3.2 formed the complex favorably and quickly with left-handed helix PLP(II), whereas PDGA having a left-handed helix at pH 3.2 favorably formed the complex with right-handed helix PLP(I). 相似文献
43.
Molecular imprinted polymer is an artificial receptor made by imprinting molecules of a template in a polymer matrix followed by removing the template molecules via thorough washing to give the permanent template grooves. They show favored affinity to the template molecule compared to other molecules, and this property is the basic driving force for such diverse application of this techniques. Such techniques have been increasingly employed in a wide scope of applications such as chromatography, sample pretreatment, purification, catalysts, sensors, and drug delivery, etc., mostly in bioanalytical areas. A major part of them is related to development of new stationary phases and their application in chromatography and sample pretreatment. Embodiments of molecular imprinted polymer materials have been carried out in a variety of forms such as irregularly ground particles, regular spherical particles, nanoparticles, monoliths in a stainless steel or capillary column, open tubular layers in capillaries, surface attached thin layers, membranes, and composites, etc. There have been numerous review articles on molecular imprinted polymer issues. In this special review, the reviews in recent ca. 10 years will be categorized into several subgroups according to specified topics in separation science, and each review in each subgroup will be introduced in the order of date with brief summaries and comments on new developments and different scopes of prospects. Brief summaries of each categories and conclusive future perspectives are also given. 相似文献
44.
Fátima Milhano Santos Augusto Quaresma Pedro Rui Filipe Soares Rita Martins Maria João Bonifácio João António Queiroz Luís António Passarinha 《Journal of separation science》2013,36(11):1693-1702
Despite of membrane catechol‐O‐methyltransferase (MBCOMT, EC 2.1.1.6) physiological importance on catecholamines’ O‐methylation, no studies allowed their total isolation. Therefore, for the first time, we compare the performance of three hydrophobic adsorbents (butyl‐, epoxy‐, and octyl‐Sepharose) in purification of recombinant human COMT (hMBCOMT) from crude Brevibacillus choshinensis cell lysates to develop a sustainable chromatographic process. Hydrophobic matrices were evaluated in terms of selectivity and hMBCOMT's binding and elution conditions. Results show that hMBCOMT's adsorption was promoted on octyl and butyl at ≤375 mM NaH2PO4, while on epoxy higher concentrations (>850 mM) were required. Additionally, hMBCOMT's elution was promoted on epoxy, butyl, and octyl using respectively 0.1–0.5, 0.25–1, and 1% of Triton X‐100. On butyl media, a stepwise strategy using 375 and 0 mM NaH2PO4, followed by three elution steps at 0.25, 0.7 and 1% Triton X‐100, allowed selective hMBCOMT isolation. In conclusion, significant amounts of MBCOMT were purified with high selectivity on a single chromatography procedure, despite its elution occurs on multiple peaks. Although successful applications of hydrophobic interaction chromatography in purification of membrane proteins are uncommon, we proved that traditional hydrophobic matrices can open a promising unexplored field to fulfill specific requirements for kinetic and pharmacological trials. 相似文献
45.
The efficient synthesis of 2-phenylethynyl- or 2-phenylthioethynyl-2-substituted phenylacetonitriles 4 and 5 from nitriles 3 and substituted dichloroethenes 1 or 2, respectively, in the presence of 50% aqueous sodium hydroxide and tetrabutylammonium hydrogen sulphate (TBAHS) as a catalyst (phase-transfer catalysis, PTC), has been accomplished. 相似文献
46.
Alessandra S. Kiametis João B. L. Martins Luiz A. S. Romeiro Ricardo Gargano 《International journal of quantum chemistry》2013,113(10):1461-1466
Alzheimer's disease is the leading cause of dementia for elderly people. The main active therapeutic is supported on the increased levels of acetylcholine in the synaptic cleft, based on reversible inhibition of the acetylcholinesterase (AChE) enzyme. This article aims to propose possible inhibitor candidates for AChE, designed from nonisoprenoid lipids of cashew (Anacardium occidentale), and based on several electronic properties. These electronic properties were obtained through B3LYP/6‐311+G(2d,p) calculation level. Principal component analysis reveals that from the set of studied molecular structures a small group is correlated with donepezil, a drug with known biological activity. © 2012 Wiley Periodicals, Inc. 相似文献
47.
Paula Gomes Maria João Araújo Eduardo F. Marques Soraia Falcão Rodrigo O. Brito 《合成通讯》2013,43(12):2025-2036
Double-chained surfactants with potential biocompatibility have been prepared in high yields by lysine acylation with four natural saturated fatty acids (C6 to C12) and with cis-undec-5-enoic acid. The surfactants were found to assemble into nanotubules in aqueous medium and, when mixed with a commercial cationic surfactant, to spontaneously form liposomes. 相似文献
48.
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50.
Sang-Eun?Lee Tae-Min?Jo Hyang-Yeol?Lee Jongsung?Lee Kyung-Hwan?JungEmail author 《Applied biochemistry and biotechnology》2013,171(6):1299-1312
We synthesized galactosyl chlorphenesin (CPN-G) using β-gal-containing Escherichia coli (E. coli) cells in which the conversion yield of chlorphenesin (CPN) to CPN-G reached about 64 % during 12 h. CPN-G was identified and characterized using high-performance liquid chromatography, liquid chromatography-mass spectrometry, Fourier transform-infrared spectrometry, and nuclear magnetic resonance analysis (1H and 13C). We verified that a galactose was covalently bound to a CPN alcohol group during CPN-G synthesis throughout these analyses. In particular, by the hydrolysis of CPN-G using β-gal, it was confirmed that a galactose was bound to CPN. The minimal inhibitory concentration (MIC) results showed that the CPN-G MICs were fairly similar to those of CPN. HACAT cell viability was significantly higher in CPN-G-treated cells than in CPN-treated cells at concentrations of 0.0–20.0 mM. Finally, we accomplished the synthesis of less toxic CPN-G, compared with CPN, using β-gal-containing E. coli cells as whole cells without changes in the MICs against microorganisms. 相似文献