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21.
Erol Akyİlmaz Şenay Hamarat Baysal Erhan DİnÇkaya 《International journal of environmental analytical chemistry》2013,93(10-11):755-761
Biosensors can be developed using different biological materials and immobilization technologies. Enzymes are generally used in biosensor construction, and some enzymes need metal ions or small organic molecules as a cofactor for their activation. Polyphenol oxidases can be activated by several metal ions such as Cu2+, Mg2+, Zn2+, Mn2+, and Ni2+. In this study, a new measurement method has been developed that is based on the metal ion activation of the polyphenol oxidase enzyme used in the biosensor preparation, especially to determine the concentration of Mg2+ ions. Polyphenol oxidase (PPO) (EC 1.10.3.1) was partially purified from potato (Solanum tuberosum) by using (NH4)2SO4 precipitation, dialysis, and lyophylization processes. As a result of this processes, approximately 30-fold purification was achieved for PPO. For construction of the biosensor, the enzyme was immobilized on the dissolved oxygen probe membrane using gelatin and glutaraldehyde (2.5%). Using the biosensor, we obtained responses for catechol in the absence and presence of Mg2+ ions. Differences between the biosensor responses were related to the concentration of Mg2+ ions. The biosensor response depends linearly on concentration of Mg2+ ions between 0.05 and 7.5?mM. In the optimization studies, phosphate buffer (pH 7.0, 50?mM) and 35°C were determined to be the optimum conditions. This project will be a novel biosensor study and it might bring a new term, ‘activation based biosensor’ into the biosensor area. 相似文献
22.
Asım Davulcu Hüseyin Benli Yasin Şen M. İbrahim Bahtiyari 《Cellulose (London, England)》2014,21(6):4671-4680
Application of natural dyes for textiles is increasing due to awareness of environment, ecology, and pollution control. The purpose of this study is to determine the color, antimicrobial, and fastness properties of cotton fabrics dyed with thyme and pomegranate peel without a mordanting process. In this way, it was planned to avoid use of metallic mordants (heavy-metal salts) and prevent heavy-metal pollution for ecological production. Additionally, a variety of the most commonly used mordants, namely potassium aluminum sulfate, copper(II) sulfate, iron(II) sulfate, and tin(II) chloride, were used for mordanting of cotton fabrics in order to compare the differently mordanted and unmordanted dyed fabrics’ color efficiencies (K/S) and CIE L * a * b * color values. It was found that mordant type had an effect on color efficiency and the color coordinates of fabrics dyed with both thyme and pomegranate fruit peel. Moreover, the antimicrobial properties of the fabrics only dyed directly with thyme and pomegranate peel without any mordanting process were determined to demonstrate the usability of these natural dye sources without use of any mordanting agents. The obtained antimicrobial activities were compared with undyed samples. Undyed samples showed no antimicrobial activity, whereas significant antimicrobial activity was obtained after the dyeing procedure using thyme and pomegranate peel on unmordanted fabrics. Washing, rubbing, perspiration, and lightfastness properties of dyed fabrics were also evaluated. Thyme and pomegranate fruit peel as natural dye sources revealed sufficient results even for unmordanted samples. 相似文献
23.
Fatma Başak Aydemir Akın Günay Figen Öztoprak Ş. İlker Birbil Pınar Yolum 《Journal of Global Optimization》2013,57(2):499-519
This paper proposes the use of multiagent cooperation for solving global optimization problems through the introduction of a new multiagent environment, MANGO. The strength of the environment lays in its flexible structure based on communicating software agents that attempt to solve a problem cooperatively. This structure allows the execution of a wide range of global optimization algorithms described as a set of interacting operations. At one extreme, MANGO welcomes an individual non-cooperating agent, which is basically the traditional way of solving a global optimization problem. At the other extreme, autonomous agents existing in the environment cooperate as they see fit during run time. We explain the development and communication tools provided in the environment as well as examples of agent realizations and cooperation scenarios. We also show how the multiagent structure is more effective than having a single nonlinear optimization algorithm with randomly selected initial points. 相似文献
24.
The problem of embedding of linear spaces in finite projective planes has been examined by several authors ([1], [2], [3], [4], [5], [6]). In particular, it has been proved in [1] that a linear space which is the complement of a projective or affine subplane of order m is embeddable in a unique way in a projective plane of order n. In this article, we give a generalization of this result by embedding linear spaces in a finite projective plane of order n, which are complements of certain regularA-affine linear spaces with respect to a finite projective plane. 相似文献
25.
Ozlem Karahan Duygu Avci Vİktorya Avİyente 《Journal of polymer science. Part A, Polymer chemistry》2011,49(14):3058-3068
A series of alkyl α‐hydroxymethacrylate derivatives with various secondary functionalities (ether, ester, carbonate, and carbamate) and terminal groups (alkyl, cyano, oxetane, cyclic carbonate, phenyl and morpholine) were synthesized to investigate the effect of intermolecular interactions, H‐bonding, π–π interactions, and dipole moment on monomer reactivity. All of the monomers except one ester and one ether derivative are novel. The polymerization rates, determined by using photo‐DSC, showed the average trend (aromatic carbamate > hydroxyl > ester > carbonate ~ aliphatic carbamate ~ ether), with several exceptions due to the differences in terminal groups. There is a correlation between the chemical shift differences of the double bond carbons, the calculated dipole moments, and the reactivities only for nonhydrogen bonded monomers. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
26.
Let (u
n
) be a sequence of real numbers. In this paper we introduce some Tauberian conditions in terms of regularly generated sequences
for (A, k) summability method. 相似文献
27.
The title polymeric complex {[Mn(O2C(CF2)8CO2)(phen)2]H2O}n was synthesized through the reaction of 1,10-phenanthroline, perfluorosebacic acid and MnCO3 · H2O. The molecular structure was characterized by X-ray diffraction, elemental analysis, thermal gravimetry, IR and UV–Vis spectroscopy and its catalytic activity has been studied. X-ray structure analysis shows that each Mn(II) ion is octahedrally coordinated by two bidentate phenanthroline ligands and the carboxylate oxygen atoms from two symmetry related perfluorosebacate ligands, which are coordinated in cisoid positions. The structure consists of polymeric chains, with the perfluorosebacato ligand bridging the Mn(II) ions in a monodentate fashion. Crystallographic characterization shows a supramolecular structure involving hydrogen bonds, π–π and π-ring interactions. The catalytic results indicated that the complex has reasonably good activity towards the disproportionation of hydrogen peroxide into water and dioxygen in methanol and it does not exhibit saturation kinetics with the substrate. The initial reaction rates and their temperature and base dependencies were investigated by monitoring the dioxygen evolution. Kinetic studies revealed a first-order dependence on the catalyst concentration. Activation parameters have been calculated at 301 K. 相似文献
28.
Beam search (BS) is used as a heuristic to solve various combinatorial optimization problems, ranging from scheduling to assembly line balancing. In this paper, we develop a backtracking and an exchange-of-information (EOI) procedure to enhance the traditional beam search method. The backtracking enables us to return to previous solution states in the search process with the expectation of obtaining better solutions. The EOI is used to transfer information accumulated in a beam to other beams to yield improved solutions. 相似文献
29.
Energetic and structural stability of Al2B2H2n (n = 0—6) clusters is investigated by DFT calculations and a stochastic search algorithm. 相似文献
30.
Emine Özge Karaca Mitat Akkoç Muhammad Nawaz Tahir Cengiz Arıcı Fatma İmik Nevin Gürbüz Sedat Yaşar İsmail Özdemir 《Tetrahedron letters》2017,58(36):3529-3532
A series of seven-membered ditopic ring-expanded N-heterocyclic carbene (dre-NHC) precursors, bearing sterically demanding and electron-rich aryl groups, were synthesised in moderate yields via the reaction of 1,2,4,5-tetrakis(bromomethyl)benzene with the corresponding N,N′-diarylformamidines in the presence of K2CO3 in acetonitrile under an air atmosphere. All new compounds were characterised by HRMS, NMR spectroscopy, and microanalysis, as well as X-ray crystallography for compound 1c. The development of an efficient catalytic system for the Suzuki-Miyaura coupling reaction of aryl chlorides with various boronic acids was also investigated using the in situ generated dre-NHC ligands. 相似文献