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61.
Deniz Akta? Uygun Begüm Akduman Murat Uygun Sinan Akg?l Adil Denizli 《Applied biochemistry and biotechnology》2012,167(3):552-563
Supermacroporous poly(2-hydroxyethyl methacrylate) [poly(HEMA)] monolithic cryogel was prepared by radical cryocopolymerization of HEMA with N,N??-methylene bisacrylamide as crosslinker. Reactive Green 5 dye was immobilized to the cryogel with nucleophilic substitution reaction, and this dye attached cryogel column was used for affinity purification of papain from Carica papaya latex. Reactive Green 5-immobilized poly(HEMA) cryogel was characterized by swelling studies, Fourier transform infrared spectroscopy, scanning electron microscopy, and energy dispersive X-ray analysis. Maximum papain adsorption capacity was found to be 68.5?mg/g polymer while nonspecific papain adsorption onto plain cryogel was negligible (3.07?mg/g polymer). Papain from C. papaya was purified 42-fold in single step with dye attached cryogel, and purity of papain was shown by silver-stained sodium dodecyl sulfate?Cpolyacrylamide gel electrophoresis. 相似文献
62.
The preparation and dynamic behavior of degenerate rotaxane molecular shuttles are described in which a benzylic amide macrocycle moves back and forth between two naphthalimide-glycine units along a diphenylethyne spacer or an aliphatic spacer consisting of a C(9), C(12), or C(26) alkyl chain. Subtle differences in the (1)H NMR spectra of the rotaxanes can be related to the presence of conformers in which the macrocycle interacts simultaneously with both glycines, especially in the case of the C(9) spacer. The kinetic data of the shuttling behavior in the C(26) rotaxane were obtained from dynamic NMR spectroscopy. The Eyring activation parameters were found to be ΔH(?) = 10 ± 1 kcal mol(-1), ΔS(?) = -6.5 ± 2.0 cal mol(-1) K(-1), ΔG(?)(298) = 11.9 ± 0.2 kcal mol(-1). For the systems with the shorter spacers, the shuttling rates were higher. Also in the diphenylethyne, rotaxane shuttling is rapid on the NMR time scale, indicating that the rigid unit does not impose a large barrier to the translocation of the macrocycle. 相似文献
63.
We consider a biodiesel production company that collects waste vegetable oil from source points that generate waste in large amounts. The company uses the collected waste as raw material for biodiesel production. The manager of this company needs to decide which of the present source points to include in the collection program, which of them to visit on each day, which periodic routing schedule to repeat over an infinite horizon and how many vehicles to operate such that the total collection, inventory and purchasing costs are minimized while the production requirements and operational constraints are met. For this selective and periodic inventory routing problem, we propose two different formulations, compare them and apply the better performing one on a real-world problem with 36 scenarios. We generate lower bounds using a partial linear relaxation model, and observe that the solutions obtained through our model are within 3.28% of optimality on the average. Several insights regarding the customer selection, routing and purchasing decisions are acquired with sensitivity analysis. 相似文献
64.
Qader Ibrahim Nazem Kok Mediha Cirak Zehra Deniz 《Journal of Thermal Analysis and Calorimetry》2021,145(2):279-288
Journal of Thermal Analysis and Calorimetry - In this study, the thermal stability and phase transformation of Ni50-xTi50Snx (x?=?0.5, 1.0, 1.5, 2.0, 2.5, 3.0, and 3.5 at%) SMAs have... 相似文献
65.
Starting from the notion of thickness of Parks we define a notion of robustness for arbitrary subsets of Rk and we investigate its relationship with the notion of positive reach of Federer. We prove that if a set M is robust, then its boundary ∂M is of positive reach and conversely (under very mild restrictions) if ∂M is of positive reach, then M is robust. We then prove that a closed non-empty robust set in Rk (different from Rk) is a codimension zero submanifold of class C1 with boundary. As a partial converse we show that any compact codimension zero submanifold with boundary of class C2 is robust. Using the notion of robustness we prove a kind of stability theorem for codimension zero compact submanifolds with boundary: two such submanifolds, whose boundaries are close enough (in the sense of Hausdorff distance), are diffeomorphic. 相似文献
66.
Mean squared error (MSE) has been the dominant criterion in adaptive filter theory. A major drawback of the MSE criterion in linear filter adaptation is the parameter bias in the Wiener solution when the input data are contaminated with noise. We propose and analyze a new augmented MSE criterion called the Error Whitening Criterion (EWC). EWC is able to eliminate this bias when the noise is white. We will determine the analytical solution of the EWC, discuss some interesting properties, and develop stochastic gradient and other fast algorithms to calculate the EWC solution in an online fashion. The stochastic algorithms are locally computable and have structures and complexities similar to their MSE-based counterparts (LMS and NLMS). Convergence of the stochastic gradient algorithm is established with mild assumptions, and upper bounds on the step sizes are deduced for guaranteed convergence. We will briefly discuss an RLS-like Recursive Error Whitening (REW) algorithm and a minor components analysis (MCA) based EWC-total least squares (TLS) algorithm and further draw parallels between the REW algorithm and the Instrumental Variables (IV) method for system identification. Finally, we will demonstrate the noise-rejection capability of the EWC by comparing the performance with MSE criterion and TLS. 相似文献
67.
Asymmetric organocatalytic sulfa-Michael reactions give access to enantiomerically enriched sulfur containing adducts that can be used as valuable chiral building blocks. A variety of chalcone derivatives were allowed to react with methyl thioglycolate under optimized conditions, in the presence of a bifunctional quinine derived sterically encumbered squaramide organocatalyst, giving rise to excellent stereoselectivities, up to 99%?ee. The designed catalyst system proved to be efficient even at gram scale and under milder reaction conditions. 相似文献
68.
Iridoid glycosides from Globularia davisiana 总被引:1,自引:0,他引:1
Caliş I Kirmizibekmez H Taşdemir D Ireland CM 《Chemical & pharmaceutical bulletin》2002,50(5):678-680
From the ethanolic extract of the aerial parts of Globularia davisiana, a new iridoid glycoside, davisioside (1), was isolated. Davisioside (1) comprises a rare iridoid aglycone structure with a saturated double bond between C-3 and C-4. Nine known iridoid glycosides, asperuloside (2), alpinoside (3), geniposide (4), globularin (5), globularicisin (6), 10-O-benzoylcatalpol (7), lytanthosalin (8), melampyroside (9), agnuside (10), and three known phenylethanoid glycosides, verbascoside, isoacteoside and leucosceptoside A were also isolated and characterized. The structures of the isolates were established by spectroscopic methods (one-dimensional (1D)- and two-dimensional (2D)-NMR, MS). 相似文献
69.
Two new lucidin type anthraquinone glycosides, putorinoside A (1) and putorinoside B (2) were isolated from Putoria calabrica, in addition to two known anthraquinone glycosides, lucidin 3-O-beta-glucopyranoside (3) and lucidin 3-O-primeveroside (4). Based on spectroscopic data, putorinosides A and B were identified as 2-hydroxymethyl-1-methoxy-3,5,6-trihydroxyanthraquinone 3-O-beta-glucopyranoside and 2-hydroxymethyl-1-methoxy-3,6-dihydroxyanthraquinone 3-O-beta-glucopyranoside, respectively. 相似文献
70.