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Biochar-Embedded Soft Hydrogel and Their Use in Ag Nanoparticle Preparation and Reduction of 4-Nitro Phenol
(Taylor & Francis As, 2013) Şahiner, Nurettin; Karakoyun, Necdet; Alpaslan, Duygu; Aktas, Nahit
The authors report the synthesis of a composite hydrogel based on acrylamide-chicken biochar(AAm)-CBand its use as a template in the preparation of silver metal nanoparticles. Moreover, we demonstrate the efficient utilization of p(AAm)-CB composite hydrogel as a reactor vessel in the reduction of an organic contaminant 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). Experimental parameters affecting 4-NP reduction rate were investigated. The kinetics of the reduction reaction under different reaction conditions were also evaluated to determine the activation parameters. Activation energy for the reduction of 4-NP was 15.25kJmol1 and p(AAm)-CB-Ag composites possessed 99.45% activity after five repetitive uses.
Chemical composition, antimicrobial, antioxidant and anthocyanin activities of mosses (Cinclidotus fontinaloides (Hedw.) P.Beauv. and Palustriella commutata (Hedw.) Ochyra) gathered from Turkey
(Taylor & Francis Ltd, 2017) Yayintas, Ozlem Tonguc; Alpaslan, Duygu; Yuceer, Yonca Karagul; Yilmaz, Selehattin; Şahiner, Nurettin
Cinclidotus fontinaloides (Hedw.) P. Beauv. and Palustriella commutata (Hedw.) Ochyra were used in this study. The chemical composition of mosses in the ethanol and water extract was determined using GC-MS and FT-IR. Antioxidant activities of moss extracts were tested by total phenol and ABTS methods. Trolox equivalent value (TEAC) of mosses was calculated as 26 +/- 0.32 and 10 +/- 0.22 mg/g. The amounts of the flavonoid compounds were calculated as mg gallic acid. Gallic acid equivalent value of mosses was calculated as 587 +/- 0.55 and 496 +/- 0.22 mg/g. The extracts antimicrobial activity was tested against Escherichia coli (ATCC 8739), Bacillus subtilis (ATCC 6633), Staphylococcus aureus (ATCC 6538), Pseudomonas aeruginosa (ATCC 10145) and Candida albicans (ATCC 10231). Significant antibacterial effect was observed for C. fontinaloides and P. commutata in ethanol extract. Total anthocyanin activities of C. fontinaloides and P. commutata were determined as 50 +/- 0.17 and 144 +/- 0.33 mg/L. [GRAPHICS] .
Metal-Ion-Containing Ionic Liquid Hydrogels and Their Application to Hydrogen Production
(Wiley, 2014) Şahiner, Nurettin; Alpaslan, Duygu
A cationic hydrogel synthesized from (3-acrylamidopropyl) trimethyl ammonium chloride as poly[(3-acrylamidopropyl) trimethyl ammonium chloride] [p(APTMACl)] was put into contact with the chloride salts of metals such as CoCl2, NiCl2, and CuCl2 in ethanol. The metal-loaded p(APTMACl) hydrogels were used as catalyst systems in hydrogen generation from the hydrolysis of sodium borohydride (NaBH4) and ammonia borane. The activation energy values for the hydrolysis reaction were calculated for all of the catalyst systems and were found to be 53.43 and 26.74 kJ/mol for p(APTMACl)-[CoCl4](2-) and p(APTMACl)-[NiCl4](2-), respectively. These activation parameters were better than values reported in the literature for the ionic liquid metal complexes of smaller molecules used for the same purpose. (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40183.
Milk hydrogels as nutrient media and survival rate enhancer under cryogenic conditions for different microorganisms
(Springer, 2016) Alpaslan, Duygu; Şahiner, Mehtap; Yüceer, Yonca; Akçalı, Alper ; Aktaş, Nahit; Şahiner, Nurettin
Milk-containing hydrogels from 2-hydroxyethylmethacrylate (HEMA) and acrylamide (AAm) as p(HEMA)/whole milk, p(HEMA)/semi-skimmed milk, p(HEMA)/skimmed milk, p(AAm)/whole milk, p(AAm)/semi-skimmed milk, p(AAm)/skimmed milk were synthesized by conventional redox polymerization technique using corresponding monomers and milk as solvents. The aim of this study was to investigate the use of milk-containing hydrogels as a nutritional medium, e.g., up 124 days for enhanced or longer cryostorage media for various microorganisms such as Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis, and fungi, Aspergillus niger, Aspergillus fumigates, and a yeast Candida albicans. It was shown that milk hydrogels can be used as nutritional media for the growth of these microorganisms, whereas the control hydrogels cannot be used for the same purpose. The survival rates of p(HEMA)/whole milk and p(AAm)/whole milk hydrogels for E. coli after 124 days were found to exceed those of the control p(HEMA) and p(AAm) hydrogels by 109- and 56-fold, respectively. Moreover, the survival rates for S. aureus were calculated to be 42 and 24 times longer than the controls, as the hydrogels containing whole milk were used as storage media in comparison with the bare hydrogels. Furthermore, the cryogenic survival rates of p(HEMA)/whole milk and p(AAM)/whole milk were compared with whole milk and nutrient broth used as a control, and calculated to be 67-, 171-, 35-, and 89-fold greater, respectively, than those of the control samples for E. coli.
Optimization with response surface methodology of toluidine blue biosorption conditions from aqueous solutions by Polyporus squamosus (Huds.) Fr. and Lentinus tigrinus (Bull.) Fr. fungi as biosorbent
(Amer Chemical Soc, 2016) Alpaslan, Duygu; Ersen, Tuba; Kubilay, Senol; Uzun, Yusuf; Kul, Ali Riza; Aktas, Nahit
[Anstract Not Available]
Preparation of collagen based composite materials with synthetic polymers for potential wound dressing applications
(2014) Şahiner, Mehtap; Bütün, Sultan; Alpaslan, Duygu; Bitlisli, B. Oral
Collagen is very important part of the fibrous proteins in the living organism. Animal tissues, especially tendons main structure contain collagen. In this investigation, natural collagen (coll) modified with different synthetic monomers such as 2-hydroxy ethylmethacrylate (HEMA) and acrylamide (AAm) was prepared as p(Coll-co-HEMA) and p(Coll-co-AAm) composites to enhance collagen natural characteristics. Biocompatibility of the prepared interpenetrating polymeric network (IPN) was tested with MTT Assay and found biocompatible. Model drugs, such as Trimetoprim (TMP) and Naproxene (NP) were used as antibacterial active agents for release studies from the synthesized composite hydrogel-collagen IPN matrices. The drug-loaded IPN films release studies were carried out in bio-mimetic media. It was found that collagen-synthetic polymer matrices can be readily prepared and used for drug delivery system in the release of active agents, providing great potential in wound dressing applications.
Quantitative Clinical Diagnostic Analysis of Acetone in Human Blood by HPLC: A Metabolomic Search for Acetone as Indicator
(Hindawi Ltd, 2016) Kalkan, Esin Akgul; Şahiner, Mehtap; Cakir, Dilek Ulker; Alpaslan, Duygu; Yilmaz, Selehattin
Using high-performance liquid chromatography (HPLC) and 2,4-dinitrophenylhydrazine (2,4-DNPH) as a derivatizing reagent, an analytical method was developed for the quantitative determination of acetone in human blood. The determination was carried out at 365 nm using an ultraviolet-visible (UV-Vis) diode array detector (DAD). For acetone as its 2,4-dinitrophenylhydrazone derivative, a good separation was achieved with a ThermoAcclaim C-18 column (15 cm x 4.6mm x 3 mu m) at retention time (t(R)) 12.10 min and flowrate of 1mL min(-1) using a (methanol/acetonitrile) water elution gradient. The methodology is simple, rapid, sensitive, and of low cost, exhibits good reproducibility, and allows the analysis of acetone in biological fluids. A calibration curve was obtained for acetone using its standard solutions in acetonitrile. Quantitative analysis of acetone in human blood was successfully carried out using this calibration graph. The applied method was validated in parameters of linearity, limit of detection and quantification, accuracy, and precision. We also present acetone as a useful tool for the HPLC-based metabolomic investigation of endogenous metabolism and quantitative clinical diagnostic analysis.
Removal of As(V), Cr(III) and Cr(VI) from aqueous environment by modifiable hydrogels
(Amer Chemical Soc, 2013) Alpaslan, Duygu; Ersen, Tugba; Kubilay, Senol; Aktaş, Nahit; Şahiner, Nurettin
[Anstract Not Available]
Removal of As(V), Cr(III) and Cr(VI) from aqueous environments by poly(acrylonitril-co-acrylamidopropyl-trimethyl ammonium chloride)-based hydrogels
(Academic Press Ltd- Elsevier Science Ltd, 2015) Dudu, Tuba Ersen; Şahiner, Mehtap; Alpaslan, Duygu; Demirci, Şahin; Aktas, Nahit
Cationic poly(Acrylonitril-co-Acrylamidopropyl-trimethyl Ammonium Chloride) (p(AN-co-APTMACl)) hydrogels in bulk were synthesized by using acrylonitrile (AN) and 3-acrylamidopropyl-trimethyl ammonium chloride (APTMACl) as monomers. The prepared hydrogels were exposed to amidoximation reaction to replace hydrophobic nitrile groups with hydrophilic amidoxime groups that have metal ion binding ability. Those replacements were increased the hydrogels absorption capacity for As(V) and Cr(VI). Langmuir and Freundlich isotherms equations were utilized to obtain the best-fitted isotherm model for the absorption of the ions at different metal ion concentrations. The absorption data of As(V) ion were fitted well to Freundlich isotherm while those of Cr(VI) and Cr(III) ions were fitted well to Langmuir isotherm. The maximum absorption of poly(3-acrylamidopropyl-trimethyl ammonium chloride (p(APTMACl)) and amid-p(AN-co-APTMACl) macro gels were 22.39 mg and 21.83 mg for As(V), and 30.65 mg and 18.16 mg for Cr(VI) ion per unit gram dried gel, respectively. Kinetically, the absorption behaviors of Cr(III) and Cr(VI) ions were fitted well to a pseudo 2nd-order kinetic model and those of As(V) ions were fitted well to a pseudo 1st order kinetic model. (C) 2015 Published by Elsevier Ltd.
Super poroushydrogels as coordinating templates for in situ metal nanoparticle preparation and use as soft reactors in hydrogen production from the hydrolysis of hydrides
(Amer Chemical Soc, 2012) Şahiner, Nurettin; Sağbaş, Selin; Turhan, Tuğçe; Karacan, Elif; Seven, Fahriye; Yaşar, Alper; Alpaslan, Duygu
[Anstract Not Available]
Synthesis and preparation of responsive poly(Dimethyl acrylamide/gelatin and pomegranate extract) as a novel food packaging material
(Elsevier, 2020) Alpaslan, Duygu; Dudu, Tuba Ersen; Şahiner, Nurettin; Aktasa, Nahit
In this study a novel and smart multi-functional hydrogel (MFH) was synthesized from N, N dimethyl acrylamide (DMAAm), gelatin, citric acid (CA) and pomegranate extract (PE) for instant and easy monitoring of the color change in MFH due to changes in medium conditions such as pH and temperature. MFH was utilized as food packaging material, equipped with the developed properties. MFH was synthesized with a redox polymerization technique in film form on petri dishes. Mechanical and water resistance properties of MFH were improved by CA and N, N, methylenebisacrylamide, while PE was used to gain antimicrobial, antioxidant and anthocyanin properties. Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analyzer (TGA), Liquid Chromatography-Mass Spectroscopy (LC-MS/MS) and Scanning Electron Microscopy (SEM) instruments were utilized for characterization of MPH. FTIR revealed the existence of bonding interactions between the functional group of PE and gelatin, carbonyl groups of DMAAm and carboxylic acid groups of CA. TGA results indicate that MFH was stable up to 400 degrees C. Then the response of total antioxidant and anthocyanin activities leading to the color change in MFH were studied at different pH values. The color change in MFH was monitored even at very small pH changes in the medium. Moreover, antimicrobial activity and stability of MFH were investigated when it was tested in harsh environments and against Escherichia colt, Bacillus subtilis and Staphylococcus aureus on real samples of whole pasteurized milk and cheese for a 7-day period. It exhibited remarkable antimicrobial activity with pasteurized whole milk and cheese. It was concluded that MFH is a very good candidate to be used as biodegradable food packaging material.
The Preparation of p(acrylonitrile-coacrylamide) hydrogels for uranyl ion recovery from aqueous environments
(2014) Alpaslan, Duygu; Aktaş, Nahit; Yılmaz, Selehattin; Şahiner, Nurettin; Güven, Olgun
The synthesis of poly(acrylonitrile-co-acrylamide) (p(AN-co-AAm)) hydrogels with different amounts of acrylonitrile (AN) and acrylamide (AAm) monomers were carried out by concurrent use of redox and microemulsion polymerization techniques. The prepared hydrogels were amidoximated for sorption of uranyl ion from aqueous medium. Batch type $UO_2^{2+}$ ion sorption by p(AN-co-AAm) (0.25:1 mole ratio) was carried out and an sorption capacity of 220 mg $UO_2^{2+}$ mg/g dried hydrogel was found. The highest amount of UO22+ ion sorption, 277 mg/g dry gel was accomplished at pH 4.
Uptake of As(V) and Cr(VI) from aqueous environment by cationic poly(Acrylonitril-co-3-Acrylamidopropyl)trimethylammonium chloride) hydrogels
(Amer Chemical Soc, 2013) Ersen, Tuba; Alpaslan, Duygu; Sahan, Tekin; Aktaş, Nahit; Şahiner, Nurettin

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