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71.
Milena M. Andrade Aneli M. Barbosa Matheus R. Bofinger Robert F. H. Dekker Josana M. Messias Carmen L. B. Guedes Tiago Zaminelli Bruno H. de Oliveira Valéria M. G. de Lima Luiz H. Dall’Antonia 《Applied biochemistry and biotechnology》2013,170(7):1792-1806
The effects of soybean and castorbean meals were evaluated separately, and in combinations at different ratios, as substrates for lipase production by Botryosphaeria ribis EC-01 in submerged fermentation using only distilled water. The addition of glycerol analytical grade (AG) and glycerol crude (CG) to soybean and castorbean meals separately and in combination, were also examined for lipase production. Glycerol-AG increased enzyme production, whereas glycerol-CG decreased it. A 24 factorial design was developed to determine the best concentrations of soybean meal, castorbean meal, glycerol-AG, and KH2PO4 to optimize lipase production by B. ribis EC-01. Soybean meal and glycerol-AG had a significant effect on lipase production, whereas castorbean meal did not. A second treatment (22 factorial design central composite) was developed, and optimal lipase production (4,820 U/g of dry solids content (ds)) was obtained when B. ribis EC-01 was grown on 0.5 % (w/v) soybean meal and 5.2 % (v/v) glycerol in distilled water, which was in agreement with the predicted value (4,892 U/g ds) calculated by the model. The unitary cost of lipase production determined under the optimized conditions developed ranged from US$0.42 to 0.44 based on nutrient costs. The fungal lipase was immobilized onto Celite and showed high thermal stability and was used for transesterification of soybean oil in methanol (1:3) resulting in 36 % of fatty acyl alkyl ester content. The apparent K m and V max were determined and were 1.86 mM and 14.29 μmol min?1 mg?1, respectively. 相似文献
72.
Marcel Dekker 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(8):1017-1020
Abstract Organic salts as initiators [A? +B?: Ph?3C+ClO? 4, Ph?3C+SbCl? 6, (?)Sp? +ClO? 4, and (?)(Sp)?2 3+(ClO4)? 3] and catalysts [A +B??: (+)CSA?; A? +B??: ph?3C+(+)CSA?? and (?)Sp?+(+)CSA??] are prepared and characterized by the dissociation constant (K d), fraction of free ions (α), and specific rotation. The asymmetrically stereoselective induction of the initiators and catalysts in the polymerization of N-vinylcarbazole is in the order A? +B?? > A +B?? > A? +B?. The specific rotations of the poly(N-vinylcarbazole) (PVCZ)s obtained are generally in this order. 相似文献
73.
Theodor G. Dekker Theunis G. Fourie Friedrich O. Snyckers Cornelis J. van der Schyf 《Magnetic resonance in chemistry : MRC》1984,22(9):607-608
The 13C NMR spectra of a series of 3-allyl-, 3-prenyl- and 3-benzyl-phlorophenone compounds are reported. Relative substituent effects are discussed. 相似文献
74.
Residual Reynolds number effects in the established data for the velocity profile in turbulent boundary layers (and in pipe
or channel flows) are found to be remarkably large. We combine two eddy-viscosity models (with overlapping validity in the
inertial sublayer) and show (both analytically and numerically) that this enhancement (which involves a viscous correlation
length) arises from inner-outer sublayer interaction. 相似文献
75.
Frenk Hans Dekker Rommert Kleijn Marcel 《Mathematical Methods of Operations Research》1997,45(3):437-454
In this paper we discuss a general framework for single component replacement models. This framework is based on the regenerative structure of these models and by using results from renewal theory a unified presentation of the discounted and average finite and infinite horizon cost models is given. Finally, some well-known replacement models are discussed, and making use of the previous results an easy derivation of their cost functions is presented. 相似文献
76.
H. Dekker 《Physica A》1980,103(3):586-596
The Onsager-Machlup Lagrangian for diffusion processes in curved spaces is determined by evaluating the covariant path integral by means of a spectral analysis of smooth trajectories in Riemannian normal coordinates. The Lagrangian involves a novel curvature scalar potential term . The present treatment replaces an earlier one. 相似文献
77.
J. C. E. Dekker 《Mathematische Zeitschrift》1964,83(4):345-366
78.
H. A. M. van den Berg P. Dekker 《Applied Physics A: Materials Science & Processing》1973,2(3):137-142
Statistical Rayleigh-curve theory is applied to thin evaporated MnBi films in order to obtain information concerning the density
of wall pinning centra. The treatment results in a prediction of the coercive forceH
c and the average distance between adjacent wall pinning centra, 2L
0. The coercive forceH
cis also measured experimentally. The results of the two methods are in good agreement with each other.
The influence of dislocations on the coercive force is discussed briefly. 相似文献
79.
H. Dekker 《Physica A》1977,87(2):419-425
The sum over paths for a generalized Wiener diffusion process has been presented in a previous paper on the basis of the concept of time-local gaussian processes. This well-defined functional sum leads to a functional integral for the probability of passing from an initial state to some final state of the system. A mathematical ambiguity remained in the freedom to choose the diffusion function in the measure anywhere between the so-called prepoint for each infinitesimal transition. In the present paper we will demonstrate, for the generalized diffusion process, how a logical extension of functional integration in the sense of Stieltjes quite naturally leads to an unambiguous formulation which has the special and interesting property of being form-invariant under nonlinear transformations according to the rules of ordinary differential calculus. 相似文献
80.
M. Sc. Nikolaos Eleftheriadis M. Sc. Stephanie A. Thee M. Sc. Martijn R. H. Zwinderman Dr. Niek G. J. Leus Prof. Frank J. Dekker 《Angewandte Chemie (International ed. in English)》2016,55(40):12300-12305
Human 15‐lipoxygenase‐1 (15‐LOX‐1) plays an important role in several inflammatory lung diseases, such as asthma, COPD, and chronic bronchitis, as well as various CNS diseases, such as Alzheimer's disease, Parkinson's disease, and stroke. Activity‐based probes of 15‐LOX‐1 are required to explore the role of this enzyme further and to enable drug discovery. In this study, we developed a 15‐LOX‐1 activity‐based probe for the efficient activity‐based labeling of recombinant 15‐LOX‐1. 15‐LOX‐1‐dependent labeling in cell lysates and tissue samples was also possible. To mimic the natural substrate of the enzyme, we designed activity‐based probes that covalently bind to the active enzyme and include a terminal alkene as a chemical reporter for the bioorthogonal linkage of a detectable functionality through an oxidative Heck reaction. The activity‐based labeling of 15‐LOX‐1 should enable the investigation and identification of this enzyme in complex biological samples, thus opening up completely new opportunities for drug discovery. 相似文献