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1.
M. Yakup Arca Meltem Ylmaz Emine Yaln Gülay Bayramo
lu 《Journal of membrane science》2004,240(1-2):167-178
Poly(hydroxyethyl methacrylate), pHEMA, and a composite pHEMA/chitosan networks were synthesized in the membrane form via UV initiated photo-polymerisation in the presence of an initiator ,′-azoisobutyronitrile. Reactive Yellow 2 (RY-2) was covalently immobilised as a dye–ligand onto both membranes. The polarity and surface energy of the investigated membranes were determined by contact angle measurement. The incorporation of chitosan in the pHEMA networks produced more hydrophilic surface, as indicated by contact angle analysis. The binding characteristics of lysozyme, γ-globulins, human serum albumin (HSA) and bovine serum albumin (BSA) to pHEMA-RY-2 and pHEMA/chitosan-RY-2 affinity membranes have been investigated from aqueous solution and their dye–ligand free forms were used as control systems. When chitosan was incorporated in the pHEMA network as a cationic polymer led to higher adsorption capacity for the lysozyme. Selective adsorption behaviour was also observed in the case of pHEMA/chitosan-RY-2 membrane for the lysozyme. The non-specific adsorptions of the lysozyme on the pHEMA and pHEMA/chitosan membranes were about 1.9 and 7.2 mg/ml, respectively. These were negligible for all others investigated proteins. The lysozyme adsorption data was analysed using the first-order and the second-order models. The first-order equation in both affinity membrane systems is the most appropriate equation to predict the adsorption capacities of the adsorbents. The adsorption isotherms well fitted the combined Langmuir–Freundlich model. A theoretical analysis has been conducted to estimate the thermodynamic contributions (changes in enthalpy, entropy and Gibbs free energy) for the adsorption of lysozyme to both dye–ligand immobilised membranes. The adsorption capacities of both dye–ligand immobilised membranes increased with increasing the temperature while decreased with increasing the NaCl concentration. Both affinity membranes are stable when subjected to sanitization with sodium hydroxide after repeated separation–elution cycles. 相似文献
2.
Polyurethane (PU) foams can be used in many remediation applications as an isolation material to prevent the release of hazardous materials into the environment. The integrity of a PU foam was investigated in this study using short-term accelerated laboratory experiments including bioavailability assays, soil burial experiments, and accelerated bioreactors to determine the fate of PU foam in the soil where anaerobic processes are dominant. The experimental results have shown that the studied PU foam is likely not biodegradable under anaerobic conditions. Neither weight loss nor a change in the tensile strength of the PU material after biological exposure was observed. The FT-IR chemical signature of the PU foams was also nearly identical before and after biological exposure. The composition of the PU material (aromatic polyester and polyether PU) used in this study could have played a significant role in its resistance to microbial attack during the short-term accelerated experiments. 相似文献
3.
Esra Imamoglu Meltem Conk Dalay Fazilet Vardar Sukan 《Applied biochemistry and biotechnology》2013,171(8):2065-2074
Agricultural by-products are becoming an attractive substrate for bioethanol production. The aim of this study was to evaluate the effects of regional differences in the rice hulls using Escherichia coli KO11 for bioethanol production. The rice hulls coded Edirne were obtained from Thrace Region, and the rice hulls coded Izmir were obtained from Aegean Region in Turkey. Rice hulls were treated by dilute acid before using them as substrates. The cells were incubated on an orbital shaker at 160 rpm under 30 °C during 96 h of the fermentation period. It was found that the maximum yield of ethanol from sugar (0.44 g ethanol/g reducing sugar) was obtained with the substrate C/N ratio of 29.16 in Izmir medium. The main difference was the dominant carbon source available as a substrate. It was detected that glucose concentration was about 2.5 times higher in Izmir medium, whereas xylose concentration was about two times higher in Edirne medium. The different results obtained with rice hulls from different origins could depend on the type of paddy as well as different cultivation conditions. These findings provide a valuable indicator for identifying suitable agricultural waste materials to be used as substrates for bioethanol production. 相似文献
4.
Cellulose - Polyacrylonitrile (PAN)-based carbon precursor is a well-established and researched material for electrodes in energy storage applications due to its good physical properties and... 相似文献
5.
Esin Burunkaya Nadir Kiraz Ömer Kesmez Meltem Asilturk H. Erdem Çamurlu Ertuğrul Arpaç 《Journal of Sol-Gel Science and Technology》2010,56(2):99-106
In this study, new fluorinated silane system was prepared by adding hydroxyl terminated Fluorolink D10H oligomer to 3-isocyanatopropyltrietoxysilane. The obtained silane system was independently composed with 3-Glycidyloxypropyltrimethoxysilane
and 3-Glycidyloxy-propyltriethoxysilane. Then the prepared two different coating solutions were applied to glass surface by
spin-coating method. The chemical bonding between groups in system was investigated by FTIR analysis. The elemental composition
of coatings was determined by using EDX analysis. Their structure and surface properties were analyzed by scanning electron
microscopy, atomic force microscopy, contact angle measurement and UV–vis spectrophotometer. The amounts of fluorine on the
coatings prepared with IPTES-D10H-GLYEO and IPTES-D10H-GLYMO were 33 and 34 %wt, respectively. Transparent coatings with smooth
surface and uniform thickness were obtained. The coatings had nanoscale roughness. The contact angles of coatings for water
were range from 103° to 110°, and for n-hexadecane were range from 59° to 62°. 相似文献
6.
Esra Imamoglu Meltem Conk Dalay Fazilet Vardar Sukan 《Applied biochemistry and biotechnology》2010,160(3):764-772
The objectives of the present study on the growth of Haematococcus pluvialis were to indicate the effects of a long-term semi-continuous cultivation, sterilization, carbon dioxide, and different culture media by using artesian well water. This investigation was an enterprise in order to commercialize the production economically. When the effect of CO2 was investigated in basal culture medium, the influence of sterilization was also researched in Rudic’s culture medium in vertical panel-type photobioreactors for 31 days of semi-continuous cultivation. The maximum cell concentration of 10.55?×?105 cells ml?1, which corresponds to the growth rate of 0.271 day?1 with the areal productivity of 3.531 g m?2 day?1, was found in non-sterilized RM medium on the 24th day of the third run of semi-continuous cultivation at a renewal rate of 50% in a vertical panel-type photobioreactor. 相似文献
7.
8.
Ömer Kesmez Nadir Kiraz Esin Burunkaya H. Erdem Çamurlu Meltem Asiltürk Ertuğrul Arpaç 《Journal of Sol-Gel Science and Technology》2010,56(2):167-176
SiO2 sols were prepared by hydrolysis and condensation reactions of tetraethyl orthosilicate through a one step acid or a two
step acid + base catalysis process, in the presence of nitric acid and four different base catalyzers, namely trimethylamine,
triethylamine, tripropylamine and tributylamine. Hydrolysis of TEOS was followed by FT-IR analyses. Particle size distributions
of the sols were evaluated after predetermined durations in 1–22 days. Particle growth was seen to be faster in amine catalyzed
systems than in one step acid catalyzed system. The highest rate of growth was in triethylamine catalyzed system. Glass substrates
were dip coated with the prepared SiO2 sols. Effect of sol aging duration on film thickness and on light transmittance properties of the films was investigated
with respect to type of base catalyst. Thicknesses of the films which were measured to be in the range of 100–400 nm, were
seen to increase with aging duration of the sols. Triethylamine catalyzed system presented the highest film thickness. Films
obtained from one step acid catalyzed system presented an increase of 4.8%; whereas acid + base catalyzed films provided an
increase in the light transmittance of 5.7% in the first 4 days of aging. Surfaces of films were examined by FESEM and AFM.
The antireflective character of the films was verified by diffuse reflectance analyses. 相似文献
9.
Meltem Öztürk 《Annals of Operations Research》2008,163(1):177-196
Semiorders may form the simplest class of ordered sets with a not necessarily transitive indifference relation. Their generalization
has given birth to many other classes of ordered sets, each of them characterized by an interval representation, by the properties
of its relations or by forbidden configurations. In this paper, we are interested in preference structures having an interval
representation. For this purpose, we propose a general framework which makes use of n-point intervals and allows a systematic analysis of such structures. The case of 3-point intervals shows us that our framework
generalizes the classification of Fishburn by defining new structures. Especially we define three classes of ordered sets
having a non-transitive indifference relation. A simple generalization of these structures provides three ordered sets that
we call “d-weak orders”, “d-interval orders” and “triangle orders”. We prove that these structures have an interval representation. We also establish
some links between the relational and the forbidden mode by generalizing the definition of a Ferrers relation. 相似文献
10.
In this article, we study the C4- and D4-modules in terms of perspective direct summands, providing new characterizations and results. Endomorphism rings of C4-modules and extensions of right C4-rings are also investigated. Decompositions of C4-modules with restricted ACC on direct summands and D4-modules with restricted DCC on direct summands are obtained. 相似文献