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61.
Sequential evaluation and process control strategy were employed for impurity profile and high recovery with quality of rhIFN-β-1b
expressed in Escherichia coli. The high-level expression was achieved by using codon substitution (AT content of 52.6% at N-terminal region) and optimization
of culture conditions. The addition of rifampicin at a concentration of 200 μg/ml has increased the specific product yield
of 66 mg optical density−1 l−1 (43.5% of total cellular protein). Eighty-three percent of lipopolysaccharides, 32% of host deoxyribonucleic acid (DNA),
and 78% of host cell proteins were removed by 0.75% Triton X-100 and 2 M urea wash. Eleven percent of lipopolysaccharides,
39% of host DNA, and 12% of host cell proteins were removed at the solubilization step. Ninety-two percent of protein refolding
was achieved by high-pressure diafiltration method. Refolding by high-pressure diafiltration, bed height, and height equivalent
to the theoretical plate value in chromatography column were identified as key parameters for high recovery with purity. Finally,
the established process yielded 34% of purified protein with greater than 99% purity and is acceptable for preclinical toxicological
studies. The purified rhIFN-β-1b obtained in this study is the highest that has been reported so far. 相似文献
62.
Abstract We study efficiency of autoionization and recombination transitions for europium in CaxCd1-xF2 host lattice depending on the energy level position of Eu2+ 4f65d1(e) excited states in respect to the conduction band (CB) states. From photoluminescence (PL) and absorption measurements we conclude that for x in the range of 1 - 0.65 thermalization within the 4f65d1(e) multiplet is faster than the appropriate autoionization transition. For x > 0.65, when all the excited 4f65d1 states are degenerate with the CB autoionization is immediate, Eu2+ intra-ion emission is quenched and a new Eu-related emission appears, which we tentatively assign to a radiative capture emission of hot nonequilibrium electrons. 相似文献
63.
A. Zahoranová M. Henselová D. Hudecová B. Kaliňáková D. Kováčik V. Medvecká M. Černák 《Plasma Chemistry and Plasma Processing》2016,36(2):397-414
Effects of a cold atmospheric pressure plasma (CAPP) treatment on the germination, production of biomass, vigor of seedlings, uptake of water of wheat seeds (Triticum aestivum L. cv. Eva) were investigated. The CAPP treatment influence on the inactivation of microorganisms occurring on the surface of wheat seeds was investigated also. The so-called Diffuse Coplanar Surface Barrier Discharge generating a cold plasma in ambient air with high power volume density of some 100 W/cm3 was used for the treatment of seeds at exposure times in the range of 10–600 s. The optical emission spectroscopy and the electrical measurements were used for estimation of CAPP parameters. The obtained results indicate that the germination rate, dry weight and vigor of seedlings significantly increased for plasma treatment from 20 to 50 s. The plasma treatment of seeds led to an extensive increase in wettability and faster germination comparing with the untreated seeds. The growth inhibition effect of CAPP on the surface microflora of wheat seeds increased with the increase of the treatment time. The efficiency of the treatment of wheat seeds artificially contaminated with pure cultures of filamentous fungi decreased in the following order: Fusarium nivale > F. culmorum > Trichothecium roseum > Aspergillus flavus > A. clavatus. 相似文献
64.
Kalyan Kali Sen Gupta Mrityunjoy Adhikari Shipra Sen Gupta 《Reaction Kinetics and Catalysis Letters》1989,38(2):313-318
The oxidation of ethanol by permanganate has been found to obey the rate law v=k[MeCHO][MnO
4
–
][H+]. The results are compared with those found for chromium (VI) oxidation of the same substrate.
V=k[MeCHO][MnO 4 – ][H+]. , (VI).相似文献
65.
Using a simple geometrical interpretation based on the Z-perturbation theory and the Hellman-Feynman theorem a Z-transition method is proposed for the calculation of total electronic energy difference of ions with respect to the isoelectronic neutral atoms. The method is particularly useful within the X-alpha like models wherein the negative ions are known to be inaccessible. 相似文献
66.
Summary A convenient method for preparing nickel(II) thiocyanate is described. Some new compounds containing nickel thiocyanate and ligands, such as OPPh3, OAsPh3, bipy, Me2NH, Et3N or N2H4 are reported, together with their structures and the nature of the bond between the thiocyanate and the metal, which has been determined by physical and chemical methods. 相似文献
67.
Summary Kinetics of the oxidation of hydrazinium ion by gold(III) have been studied spectrophotometrically in hydrochloric acid medium. The reaction is first-order with respect to both gold(III) and hydrazinium ion. Hydrogen ion inhibits the oxidation. The mechanism of the reaction is discussed. 相似文献
68.
Kalyan Kali Sen Gupta Pratik Kumar Sen Gargi Mukhopadhyay 《Transition Metal Chemistry》1993,18(4):369-371
Summary The permanganate ion oxidation of PhCHO in HClO4 medium is first order in [MnO
inf4
sup-
], but of complex order with respect to [aldehyde] as well as [H+]. The influence of substituents on the reaction rate and mechanism has also been studied in 40% (v/v) aqueous AcOH and convincing evidence favours an ester formation mechanism. Thermodynamic values associated with 11 intermediate ester formation and the activation parameters associated with the disproportionation steps involved have been evaluated. 相似文献
69.
Here is considered vibration of non-stationary carrying system of the IRb-6 robot. For a use of vibration surveillance an algorithm of modal control at energy performance index in the frequency domain has been applied. Purpose of the algorithm proposed is to minimise vibration amplitude of manipulating ends, and thus – to increase capacity of modern robot lines as well as, improve accuracy and repeatability of robot positioning. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
70.
We report a direct determination of the time dependent mean-squared segment displacement of a polymer chain in the melt covering the transition from free to constraint Rouse relaxation along the virtual tube of the reptation model. This has been achieved by a neutron spin-echo (NSE) measurement of the segmental self-correlation function as conveyed by the spin-incoherent scattering from two fully protonated polymer melts, polyethylene and polyethylene propylene. Within the scenario of de Gennes reptation model a transition of the time dependence of segmental mean-squared displacements from proportional, variant t(1/2) to proportional, variant t(1/4) is expected and clearly corroborated by the incoherent NSE results. 相似文献