The effect of humic acids on nitrobenzene oxidation by ozonation and O3/UV processes

Three types of commercially available humic acids from different sources were used to simulate natural organic matter in water for the investigation of nitrobenzene oxidation by ozonation and O(3)/UV. Despite the structural differences among the Fluka, Aldrich and Suwanee River humic acids as reflected by the UV absorptivity, their effects on nitrobenzene removal rate was observed to be similar for the two processes. Removal rate of nitrobenzene was hindered by the addition of humic acids in ozonation as well as in O(3)/UV processes. However, the hindrance by the humic acids was more pronounced in O(3)/UV as compared to the ozonation process. The effect of humic acid in O(3)/UV was primarily a UV light screening. Addition of humic acids above a certain concentration did not cause any further retardation on nitrobenzene removal rate by ozonation and O(3)/UV.Accumulation of hydrogen peroxide as well as probable formation of peroxy radicals in the solutions might induce chain promoting reactions to produce hydroxyl radical during the nitrobenzene oxidation. For waters containing high levels of humic acid, ozonation alone might be as effective as O(3)/UV process for the removal of nitrobenzene.     

Electrospun plasma‐modified chitosan/poly(ethylene terephthalate)/ferrocenyl‐substituted N‐acetyl‐2‐pyrazoline fibers for phosphate anion sensing

Two ferrocenyl‐substituted N‐acetyl‐2‐pyrazolines, N‐acetyl‐3‐(2‐furyl)‐5‐ferrocenyl‐2‐pyrazoline (Fc‐1) and N‐acetyl‐3‐(2‐thienyl)‐5‐ferrocenyl‐2‐pyrazoline (Fc‐2) electrospun fibers, were produced in the presence of plasma‐modified chitosan (PMCh)/poly(ethylene terephthalate) (PET) supporting polymers with an electrospinning method. The morphological and chemical characterizations of the PMCh/PET/Fc‐1 and PMCh/PET/Fc‐2 electrospun fibers were determined by scanning electron microscopy coupled with energy‐dispersive X‐ray spectroscopy analysis. Thermogravimetric analysis results indicated the presence of ferrocene within the PMCh/PET nanofibers. The electrochemical behavior of the PMCh/PET/Fc‐1 and PMCh/PET/Fc‐2 electrospun fibers were investigated by cyclic voltammetry measurements based on the ferrocene/ferrocenium redox couple. The new PMCh/PET/Fc‐1 and PMCh/PET/Fc‐2 electrospun fibers aggregated on the indium tin oxide were used for phosphate anion sensing. The highest oxidation peak currents were observed for the PMCh/PET/Fc‐1 electrospun fibers at about 0.56 V in 0.1M phosphate buffer. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43344.     

Investigation of the relation between meteorological parameters,North Atlantic Oscillation and groundwater levels in Torbali Region,Turkey

Groundwater, the most reliable fresh water source, is used for drinking, domestic and agricultural purposes. Thereby, understanding its behaviour is important for the sustainability of groundwater sources. In this study, relations between the trends of climate parameters [recharge depending on precipitation, temperature and North Atlantic Oscillation Index (NAOI)] and groundwater levels trend were investigated for Torbali Region in Turkey. The human impact that is one of the deterministic components on the groundwater level has been removed from the groundwater level data sets. An increasing trend was observed in the early 1990s, and turning points were determined by using paired t‐test. The trends of the groundwater levels indicate that climate parameters affect groundwater levels in the similar manner. According to the results of the analyses, it is revealed that there is a similar linear variation that is strong and inverse between the trends of NAOI and meteorological indicator (temperature and recharge) and groundwater level.     

Coenzyme Q10 supplementation and diastolic heart functions in hemodialysis patients: A randomized double‐blind placebo‐controlled trial

Coenzyme Q10 (CoQ10) supplementation has been shown to improve diastolic heart function in various patient cohorts. Systolic and diastolic dysfunctions are common in patients with end‐stage renal disease. Favorable effects of CoQ10 on cardiac functions are yet to be seen in hemodialysis patients. We aimed to evaluate effect of CoQ10 supplementation on diastolic function in a cohort of maintenance hemodialysis patients. This was a prospective, double‐blind, placebo‐controlled, crossover study in which all patients received placebo and oral CoQ10 200 mg/d during the 8 weeks in each phase, with a 4‐week washout period. Participants underwent conventional and tissue Doppler echocardiography before and after each study phase. Parameters characterizing left ventricle diastolic function and other standard echocardiographic measurements were recorded. Twenty‐eight patients were randomized, but 22 patients completed study protocol. Intraventricular septum (IVS) thickness and left ventricle mass were significantly decreased in CoQ10 group (P = 0.03 and P = 0.01, respectively). Myocardial peak systolic and early diastolic velocities derived from IVS were significantly increased (P = 0.048 and P = 0.04, respectively). Isovolumetric relaxation time and E/Em ratio calculated for IVS also significantly reduced in CoQ10 group (p = 0.02 and p = 0.04, respectively). There was no significant difference in any of the studied echocardiographic parameters in placebo group. The results of this study showed that CoQ10 supplementation did not significantly improved diastolic heart functions compared with placebo in maintenance hemodialysis patients.     

Synthesis and characterization of amino acid containing Cu(II) chelated nanoparticles for lysozyme adsorption

Immobilized metal ion affinity chromatography (IMAC) is a useful method for adsorption of proteins that have an affinity for transition metal ions. In this study, poly(hydroxyethyl methacrylate-methacryloyl-l-tryptophan) (PHEMATrp) nanoparticles were prepared by surfactant free emulsion polymerization. Then, Cu(II) ions were chelated on the PHEMATrp nanoparticles to be used in lysozyme adsorption studies in batch system. The maximum lysozyme adsorption capacity of the PHEMATrp nanoparticles was found to be 326.9 mg/g polymer at pH 7.0. The nonspecific lysozyme adsorption onto the PHEMA nanoparticles was negligible. In terms of protein desorption, it was observed that adsorbed lysozyme was readily desorbed in medium containing 1.0 M NaCl. The results showed that the metal-chelated PHEMATrp nanoparticles can be considered as a good adsorbent for lysozyme purification.     

Purification of yeast alcohol dehydrogenase by using immobilized metal affinity cryogels

In this study, poly(2-hydroxyethyl methacrylate–glycidylmethacrylate) [poly(HEMA–GMA)] cryogels were prepared by radical cryocopolymerization of HEMA with GMA as a functional comonomer and N,N′-methylene-bisacrylamide (MBAAm) as a crosslinker. Iminodiacetic acid (IDA) functional groups were attached via ring opening of the epoxy group on the poly(HEMA–GMA) cryogels and then Zn(II) ions were chelated with these structures. Characterization of cryogels was performed by FTIR, SEM, EDX and swelling studies. These cryogels have interconnected pores of 30–50 μm size. The equilibrium swelling degree of Zn(II) chelated poly(HEMA–GMA)-IDA cryogels was approximately 600%. Zn(II) chelated poly(HEMA–GMA)-IDA cryogels were used in the adsorption of alcohol dehydrogenase from aqueous solutions and adsorption was performed in continuous system. The effects of pH, alcohol dehydrogenase concentration, temperature, and flow rate on adsorption were investigated. The maximum amount of alcohol dehydrogenase adsorption was determined to be 9.94 mg/g cryogel at 1.0 mg/mL alcohol dehydrogenase concentration and in acetate buffer at pH 5.0 with a flow rate of 0.5 mL/min. Desorption of adsorbed alcohol dehydrogenase was carried out by using 1.0 M NaCI at pH 8.0 phosphate buffer and desorption yield was found to be 93.5%. Additionally, these cryogels were used for purification of alcohol dehydrogenase from yeast with a single-step. The purity of desorbed alcohol dehydrogenase was shown by silver-stained SDS–PAGE. This purification process can successfully be used for the purification of alcohol dehydrogenase from unclarified yeast homogenates and this work is the first report about the usage of the cryogels for purification of alcohol dehydrogenase.     

Characterization of polypyrrole/azocalix[4]arene salts: Electrical properties and thermal stability

Polypyrrole (PPy) was doped with the azocalix[4]arene [(5,11,17,23‐tetrakis[(p‐carboxyphenyl)azo]25,26,27,28‐tetrahydroxycalix[4]arene)] host species. PPy/azocalix[4]arene salts were characterized by FTIR, TGA, SEM, X‐ray diffraction, and conductivity measurements. The properties of PPy were investigated in the presence of azocalix[4]arene host species. The conductivity of PPy increased in the presence of azocalix[4]arene. TGA results indicated that the PPy/azocalix[4]arene salts have higher thermal stability than PPy. It was observed from SEM analysis that the particle diameter of PPy decreased with increasing content of azocalix[4]arene. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Comparative study of conducting polyaniline/copper and polyaniline/nickel composites in the presence of surfactants

Polyaniline/copper and polyaniline/nickel composites were synthesized in the presence and absence of surfactants using ammonium persulfate as an initiator. The structural and surface characteristics of the composites were studied and compared using different techniques. The interfacial interactions and thermal stability of the composites were characterized using X‐ray diffraction and thermogravimetric analysis. Surface properties were investigated using scanning electron microscopy and energy‐dispersed X‐ray spectroscopy. The results indicate significant changes in the morphological and physicochemical properties of the composites when incorporating surfactants. The surfactant‐induced surface characteristics also have an effect on conductivity. Copyright © 2010 Society of Chemical Industry     

Dissipation of organophosphorus pesticides in wheat during pasta processing

For investigating the carryover of some organophosphorus pesticide residues in the cereal food chain from grain to consumer, a study was set up on durum wheat, semolina and pasta. Pesticide-free durum wheat was placed into a small-scale model of a commercial storage vessel and treated with pesticides (malathion, fenitrothion, chlorpyrifos methyl, and pirimiphos methyl) according to the raw material legislation of Turkey. The residue levels of insecticides were determined in wheat, semolina, and spaghetti produced from stored wheat at various time intervals during five months of storage. A multiresidue analysis was performed using GC equipped with an NPD. The confirmation was performed by GC–MS. The residue levels of insecticides in wheat exceeded the maximum residue limits (MRLs) for wheat. The storage period was generally not effective enough to reduce the residues in wheat to levels below the MRLs. Although a considerable amount of the insecticides remained in the semolina, spaghetti processing significantly reduced residue concentrations in general. Pirimiphos methyl was the most persistent of the insecticides and comparatively less substantial loss occurred during milling and spaghetti processing due to its physicochemical properties.