Production and characterization of poly(vinyl alcohol)/poly(vinylpyrrolidone) iodine/poly(ethylene glycol) electrospun fibers with (hydroxypropyl)methyl cellulose and aloe vera as promising material for wound dressing

Biocompatible poly(vinyl alcohol)/poly (vinylpyrrolidone) iodine/poly(ethylene glycol) fibers containing (hydroxypropyl)methyl cellulose (HPMC) and aloe vera were successfully prepared by electrospinning their aqueous solution. Aloe vera which is known to be effective in the treatment of various wounds was added to the polymer solution. HPMC was added to the system as the water retention agent. The hybrid fiber mats were subjected to detailed analysis using a differential scanning calorimeter, a scanning electron microscope (SEM), and a Fourier transform infrared spectrometer. Images obtained from the SEM showed that the polymer fibers were linear, homogenous, and contained no beading. The fiber diameters ranged between 100 and 900 nm. It was seen that the electrospun mats obtained could potentially be used as a material for dressing wounds. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effects of fermentation time and storage on the water‐soluble vitamin contents of tarhana

Changes in water‐soluble vitamins were investigated in tarhana dough during fermentation and in tarhana stored under a variety of conditions for up to 6 months. The contents of riboflavin (P < 0.01), thiamin, niacin, vitamin B₆ and folic acid (P < 0.05) increased significantly during fermentation. The thiamin, riboflavin, niacin, vitamin B₆ and folic acid contents of tarhana dough were 4.80, 1.85, 7.68, 15.30 and 2.25 mg kg^?1 respectively at the beginning of fermentation and increased to 10.15, 5.15, 24.04, 19.35 and 6.10 mg kg^?1 respectively at the end of fermentation. Thiamin, riboflavin and folic acid contents were significantly affected (P < 0.01) by storage type and period, but niacin and vitamin B₆ contents were not affected (P > 0.05). The water‐soluble vitamin contents of tarhana stored wet were higher than those of tarhana stored dry. Drying resulted in a 24% reduction in riboflavin content and an 86% reduction in folic acid content. Copyright © 2007 Society of Chemical Industry     

Electrochemical determination of HIV drug Abacavir based on its reduction

Abacavir (I), a drug used in the treatment of HIV, is electrochemically reduced at the dropping mercury electrode in a four-electron process, similar to structurally related adenine (III) and adenosine triphosphate (IV). To undergo the reduction, the species is protonated in the vicinity of the electrode. The protonations take place on the 6-amino group and on one of the pyrimidine ring nitrogens. The role of covalent hydration of the pyrymidine ring has been interpreted. Best suited as supporting electrolytes for analytical purposes are solutions of 0.1-1.0 M sulfuric, perchloric, or hydrochloric acids. Procedures of analyses of tablets containing I were established and validated, based on peak currents obtained by linear sweep, differential pulse, or square-wave voltammetry with a hanging mercury drop electrode as indicator electrode. The procedure proved to be more sensitive and more reliable than that based on oxidation on a glassy carbon electrode, proposed previously.     

Does laser etching have an effect on application mode of a universal adhesive?—A microleakage and scanning electron microscopy evaluation

This study aimed to evaluate the microleakage of a universal adhesive's different application modes incorporated with Er,Cr:YSGG laser on Class V resin composite restorations. Sound human molar teeth (n = 30) were used for microleakage evaluations. Specimens with 60 standardized Class V cavities were divided into five groups according to the adhesive modes of universal adhesive, Adhese Universal (n = 12). Group 1‐etch‐and‐rinse mode with phosphoric acid; Group 2‐etch‐and‐rinse mode with Er,Cr:YSGG laser; Group 3‐selective‐etch mode with phosphoric acid; Group 4‐selective‐etch mode with Er,Cr:YSGG laser; Group 5‐self‐etch. After restorations were performed with a resin composite, Tetric N‐Ceram, the specimens were polished and subjected to thermocycling (10,000X). Following immersion in 0.5% basic fuschin for a day, the teeth were sectioned and the degree of microleakage was determined along the tooth‐resin composite interface using a light microscopy(40X). Five specimens from each group were examined by scanning electron microscopy. The Kruskal–Wallis, Siegel Castello, and Wilcoxon tests were used for statistical analyses (α = .05). At the enamel margins, significant differences were obtained among the groups (p < .05). Significantly higher microleakage scores were detected in Group 5 in comparison with Groups 1, 2, and 3. There were no significant differences between different adhesive strategies at the dentin margins (p > .05). While analyzing enamel and dentin microleakage scores, no statistically significant differences were observed in Groups 4 and 5 (p > .05). The laser application time and the adhesive modes of universal adhesives could affect the microleakage at the enamel margins. Different adhesive modes of universal adhesives combined with laser etching had no influence on the microleakage scores of dentin margins.     

Removal of tetracycline antibiotic by Lemna gibba L. from aqueous solutions

In this study, the efficiency of Lemna gibba L. on tetracycline (TC) removal from the solutions prepared at various initial TC concentrations (50, 100 and 300 µg/L) was investigated. The study was conducted in the reactors planted with Lemna gibba L. plants. Lemna gibba L. plants in the reactors were harvested at various hydraulic retention times. Then, the concentrations of TC were determined by using LC/‐MS‐MS. The maximum removal efficiencies for the TC50, TC100 and TC300 in the planted reactors were 99.8 ± 4.1; 99.9 ± 4.9 and 99 ± 4.9%, respectively. The harvesting times for Lemna gibba L. at TC50, TC100 and TC300 concentrations were determined to be 12, 8 and 12 hours, respectively. First‐, second‐ and pseudo‐first‐order kinetics are determined in the planted reactors (with Lemna gibba L.). According to the study results, second‐order kinetics were obtained at TC50, TC100, TC300 concentrations. As a result, the Lemna gibba L. plant can be used as an alternative treatment method to other advanced treatment methods and it can be done with a cheap method by adapting to existing treatment plants. Lemna gibba L. plants can be used to remove pollutants by applying them to polluted lakes and water bodies.     

Ozonation of Animal Wastes Containing Oxytetracycline

The efficiency of ozonation on the degradation of oxytetracycline, a veterinary antibiotic, has been investigated in both cow manure and synthetic animal feeding operation wastewater at varying experimental conditions. With a rapid degradation of antibiotic in synthetic wastewater, ozonation improved its biodegradability and eliminated bacterial toxicity caused by oxytetracycline. The degradation rate of oxytetracycline depended on pH and applied ozone dose, but not initial antibiotic concentration in wastewater. In the case of manure treatment, ozonation efficiency in terms of oxytetracycline degradation was negatively affected by moisture and antibiotic content of manure. The degradation rate of oxytetracycline in manure slowed down upon the extension of treatment time since ozone could not react with strongly adsorbed antibiotic on manure. Increase in humic and fulvic acid carbon and mineral nitrogen content was an indicator for the improvement of fertilizing value of manure by ozonation.     

Synthesis,Characterization, and Thermoelectric Properties of Electrospun Boron-Doped Barium-Stabilized Bismuth-Cobalt Oxide Nanoceramics

In this study, the boron-doped barium-stabilized bismuth cobalt oxide thermoelectric nanocrystalline ceramic powders were produced by the polymeric precursor technique. The powders were characterized by X-ray diffraction, scanning electron microscopy, and the physical properties measurement system. The X-ray diffraction results showed that these patterns have mixture of two phases as face-centered cubic and body-centered cubic. Values of the crystallite size, the dislocation density, and the microstrain were calculated by the Scherrer equation. According to these values, the crystallite size decreased from 60 to 51 nm with the boron addition in the boron-undoped and boron-doped samples, respectively. The scanning electron microscope results showed that nanograins are rarely seen in the boron-undoped samples, but nanograins turn into needle-like and layered structures with boron addition. The diameters distribution of nanofibers was calculated. The average diameter of the boron-doped sample is smaller than the boron-undoped sample. The physical properties measurement system values showed that the electrical and thermal conductivity, the Seebeck coefficient, and the figure of merit increased with the temperature rise for both samples. The boron-doping effect increased the electrical and thermal conductivity, decreased the Seebeck coefficient, and decreased the figure of merit.