Browsing by Author "Aktas, Nahit"

Now showing 1 - 20 of 132

0d, 1d, 2d, and 3d Soft and Hard Templates for Catalysis
(Elsevier Science Bv, 2017) Butun, Sultan; Demirci, Sahin; Yasar, Alper O.; Sagbas, Selin; Aktas, Nahit; Sahiner, Nurettin
3-Acrylamidopropyl Cationic Hydrogel Modified Graphite Electrode and Its Superior Sensitivity To Hydrogen Peroxide
(Taylor & Francis inc, 2019) Caglar, Aykut; Kazici, Hilal Celik; Alpaslan, Duygu; Yilmaz, Yonca; Kivrak, Hilal; Aktas, Nahit
A highly sensitive hydrogen peroxide (H2O2) sensor is fabricated by the synthesized 3-Acrylamidopropyl-trimethylammoniumchloride (p(APTMACl)) hydrogel to covered of pen- graphite (PG) electrodes. (p(APTMACl))-PG electrode is characterized using scanning electron microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy, and thermogravimetric analysis (TGA). The electrochemical properties of these sensors are investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). The CV behavior of (p(APTMACl))-PG electrode is investigated in 0.1M PBS (pH 7, 5mm diameter of mold). The developed sensor displays significantly enhanced electrocatalytic activity through the H2O2 detection. Linear response of the sensor to H2O2 were observed in the concentration range from 0 to 130 mu M (R-2 = 0.99) with a detection limit of 1.08x10(-6) M, quantification limit of 3.62x10(-6) M (S/N=3) and sensitivity of 2375 mu A/mMcm(2). In addition, interference studies reveal that (p(APTMACl))-PG electrode is not affected by ascorbic acid (AA), uric acid (UA), and dopamine which are common interfering species. The developed sensor is also successfully applied to detect H2O2 in real commercial samples. This study describes a novel strategy to sensing characteristics to hydrogen peroxide by p(APTMACl)-PG electrode.
4-Vinylpyridine Smart Nanoparticles With N-Isopropylacrylamide, 2-Hydroxyethyl Methacrylate, Acrylic Acid, and Methacrylic Acid for Potential Biomedical Applications
(Bentham Science Publ Ltd, 2011) Sahiner, Nurettin; Ozay, Ozgur; Aktas, Nahit
Stimuli-responsive (pH, temperature and magnetic field) 4-vinylpyridine (4-VP)-based nanoparticles in copolymeric formulation with core-shell morphology were synthesized using N-isopropylacrylamide (NIPAM), 2-hydroxyethyl methacrylate (HEMA), acrylic acid (AAc), and methacrylic acid (MAc) as shell-forming monomers. Keeping the 4-VP ratio constant and varying the comonomer amounts produced particles with variant shell thickness. Multi-responsive p(4-VP)-based nanoparticles were further modified by reacting with different functional groups containing bromoalkanes by quaternization. These p(4-VP)-based particles were also utilized to include composite materials by encapsulating separately prepared magnetic ferrites. To demonstrate the potential usage of the synthesized particles and their modified forms as drug delivery devices, naproxene sodium salt as an antibacterial drug was used for in vitro release studies in PBS.
Agar and Sesame Oil Based Organo-Hydrogels as a Pharmaceutical Excipient in Paracetamol/Carboplatin Release Systems
(indian Pharmaceutical Assoc, 2022) Alpaslan, Duygu; Dudu, Tuba Ersen; Aktas, Nahit
Organo-hydrogels were synthesized by using free radical polymerization in the emulsion technique, using agar, glycerol, sesame oil, ammonium persulfate as initiator and N,N'-methylene bisacrylamide or glutaraldehyde as crosslinker. Swelling behaviors, blood compatibility, antioxidant and properties of the organo-hydrogels were investigated thoroughly. The highest swelling value was seen in organo-hydrogel synthesized with the N,N'-methylene bisacrylamide crosslinker containing 0.1 ml of sesame oil. Moreover, drug release behaviors of organo-hydrogels were studied as paracetamol and carboplatin used as model drugs. Release studies were shown that some basic parameters such as medium pH and composition of the polymer structure affect organo-hydrogels drug release behavior. As a result of drug release experiments, it was observed that the release values of organo-hydrogels changed depending on sesame oil and crosslinker content. The highest paracetamol release capacities for the p (AG-m-SO)(2) and p (AG-g-SO)(2) organo-hydrogels were calculated as 45.3 % and 79.8 %. When investigated carboplatin releases, the highest releases also were founded to be 100 % for p (AG-m-SO)(2) and 85 % for p (AG-g-SO)(2).
An Alternative To Metal Catalysts: Poly(4-Vinyl Pyridine]-Based Polymeric Ionic Liquid Catalyst for H2 Generation From Hydrolysis and Methanolysis of Nabh4
(Pergamon-elsevier Science Ltd, 2016) Sahiner, Nurettin; Yasar, Alper O.; Aktas, Nahit
Monodispersed p(4-VP) (poly(4-vinyl pyridine)) polymeric particles were synthesized via self-emulsion polymerization and modified with 1,2-dibromobutane 1,4-dibromobutane and 1,6-dibromobutane, to obtain polymeric ionic liquid (PIL) particles of poly(4-vinyl pyridine)-dibromoethane (p(4-VP)C-++(2)), poly(4-vinyl pyridine)-dibromobuthane (p(4-VP)C-++(4)), and poly(4-vinyl pyridine)-dibromohexane (p(4-VP)C-++(6)) particles. Highly mono dispersed p(4-VP), p(4-VP)C-++(2), p(4-VP)C-++(4) and p(4-VP)C-++(6) particles were obtained with the sizes of 335 +/- 10, 451 +/- 17, 432 +/- 13 and 443 +/- 24 nm, and the zeta potential values of 6.3 +/- 0.6, 31.2 +/- 2.1, 33.3 +/- 1.0 and 35.5 +/- 1.1 mV. PIL-metal composites of p(4-VP)C-++(6)-Co p(4-VP)C-++(6)-Ni and p(4-VP)C-++(6)-Fe particles were prepared by reducing CoCl2, NiCl2 and FeC13 metal salts loaded into p(4-VP)C-++(6) microgels and then reducing with NaBH4. The prepared PIL-metal composites and PIL particles were used as catalysts in H-2 generation from the hydrolysis and methanolysis of NaBH4. It was found that the prepared PIL-metal composites (e.g., p(4-VP)C-++(6)-Co) showed better catalytic performances than PIL particles (e.g., p(4-VP)C-++(6)) for the hydrolysis reaction of NaBH4 whereas, PIL catalytic performances were much better than PIL-metal composites for the methanolysis of NaBH4. Various parameters affecting the hydrolysis and methanolysis reactions of NaBH4 such as the types of PIL/PIL-metal particle, the amount of PIL particles, the amount of NaBH4 and temperature were investigated. A very high hydrogen generation rate (HGR) value for the methanolysis reaction of 500 mM NaBH4 catalyzed by 50 mg p(4-VP)C-++(6) at 25 degrees C was calculated as 9125 +/- 177 mL H-2 (g of catalyst min)(-1). Furthermore, very low activation energy (Ea), 13.78 +/- 0.23 kJ morl was calculated for the methanolysis of NaBH4 catalyzed by p(4-VP)C-++(6) at temperatures in the range of 0-40 degrees C. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Amidoximated Poly(Acrylonitrile) Particles for Environmental Applications: Removal of Heavy Metal Ions, Dyes, and Herbicides From Water With Different Sources
(Wiley, 2016) Ajmal, Muhammad; Demirci, Sahin; Siddiq, Mohammad; Aktas, Nahit; Sahiner, Nurettin
Monodispersed poly(acrylonitrile) [p(AN)] particles were prepared by surfactant free emulsion polymerization and the hydrophobic nitrite groups were converted to hydrophilic amidoxime groups by treatment with hydroxylamine hydrochloride (NH2OH center dot HCl) in water. The p(AN) and amidoximated p(AN) [amid-p(AN)] particles were characterized by Fourier transformation infrared (FT-IR) spectroscopy, thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM). The prepared particles were used as adsorbents in the removal from aqueous media of three different types of pollutants; organic dyes methylene blue (MB), and rhodamine 6 G (R6G), a heavy metal ion Cd (II), and a herbicide paraquat (PQ). The effects of various parameters such as amidoximation, pH of solution, amount of particles, and the initial concentration of solution were investigated. Upon amidoximation, a great increase in the adsorption capacity of the prepared particles was observed as the adsorbed amounts were increased to 87, 91, 74, and 91 mg/g from 5, 1.54, 1.06, and 1.22 mg/g for Cd (II), MB, R6G, and PQ, respectively. The amid-p(AN) particles were also able to remove considerable amounts of these pollutants from tap, river, and sea water. Langmuir, Freundlich, and Temkin adsorption isotherms were applied and it was found that the adsorption of Cd (II) and PQ followed the Langmuir adsorption model, whereas the adsorption of MB was found to obey the Freundlich adsorption isotherm. Pseudo first-order and pseudo second-order kinetics were also applied and the results showed that the adsorption processes of Cd (II), PQ, MB, and R6G follow pseudo second-order kinetics. (C) 2015 Wiley Periodicals, Inc.
Application of Poly (agar-Co Almond Oil) Based Organo-Hydrogels as a Drug Delivery Material
(Springer, 2022) Ersen Dudu, Tuba; Alpaslan, Duygu; Aktas, Nahit
In this study, it was aimed to investigate the synthesis, characterization and drug release behaviors of organo-hydrogels containing pH-sensitive Agar (A), Glycerol (G), Sweet Almond oil (Wu et al. in J Mol Struct 882:107-115, 2008). Organo-hydrogels, which contained Agar, Glycerol and different amounts of Sweet Almond oil, were synthesized via the free-radical polymerization reaction with emulsion technique using glutaraldehyde or methylene bis acrylamide crosslinkers. Then, the degree of swelling, bond structures, blood compatibility and antioxidant properties of the synthesized organo-hydrogels were examined. In addition, Organo-hydrogels which loaded with Ceftriaxone and Oxaliplatin were synthesized with the same polymerization reaction and release kinetics were investigated. In vitro release studies were performed at media similar pH to gastric fluid (pH 2.0), skin surface (pH 5.5), blood fluid (pH 7.4) and intestinal fluid (pH 8.0), at 37 degrees C. The effects on release of crosslinker type and sweet almond oil amount were investigated. Kinetic parameters were determined using release results and these results were applied to zero and first-order equations and Korsmeyer-Peppas and Higuchi equations. Diffusion exponential was calculated for drug diffusion of organo-hydrogels and values consistent with release results were found.
An Approach for Prediction of Optimum Reaction Conditions for Laccase-Catalyzed Bio-Transformation of 1-Naphthol by Response Surface Methodology (Rsm)
(Elsevier Sci Ltd, 2008) Ceylan, Hasan; Kubilay, Senol; Aktas, Nahit; Sahiner, Nurettin
Response surface methodology (RSM) was successfully applied to enzymatic bio-transformation of 1-naphthol. The experiments were conducted in a closed system containing acetone and sodium acetate buffer, with laccase enzyme. Laccase enzyme used as catalyst was derived from Trametes versicolor (ATCC 200801). The enzymatic bio-transformation rate of I-naphthol, based oil measurements of initial dissolved oxygen (DO) consumption rate in the closed system, was optimized by the application of RSM. The independent variables, which had been found as the most effective variables on the initial DO consumption rate by screening experiments, were determined as medium temperature, pH and acetone content. A quadratic model was developed through RSM in terms of related independent variables to describe the DO consumption rate as the response. Based on contour plots and variance analysis, optimum operational conditions for maximizing initial DO consumption rate, while keeping acetone content at its minimum value, were 301 K of temperature, pH 6 and acetone content of 7% to obtain 9.17 x 10(-3) mM DO/min for initial oxidation rate. (c) 2007 Published by Elsevier Ltd.
Aromatic Organic Contaminant Removal From an Aqueous Environment by P(4-Vp) Materials
(Pergamon-elsevier Science Ltd, 2011) Sahiner, Nurettin; Ozay, Ozgur; Aktas, Nahit
p(4-vinylpyridine) (p(4-VP)) hydrogels were prepared in bulk (macro, 5 x 6 mm) and in nanosizes (370 nm) dimensions. The prepared hydrogels were used to remove organic aromatic contaminates such as 4-nitrophenol (4-NP), 2-nitrophenol (2-NP), phenol (Ph) and nitrobenzene (NB) from an aqueous environment. Important parameters affecting the absorption phenomena, such as the initial concentration of the organic species and the absorbent, absorption rate, absorption capacity, pH and the temperature of the medium, were evaluated for both hydrogel sizes. The absorption capacity of bulk and microgels were found to be 4-NP > 2-NP > Ph > NB. Furthermore, p(4-VP) microgels were embedded in poly(acrylamide) (p(AAm)) bulk hydrogel as a microgel-hydrogel interpenetrating polymer network and proved to be very practical in overcoming the difficulty of using the microgels in real applications. Moreover, it was demonstrated that separately prepared magnetic ferrite particles inserted inside p(4-VP) microgels during synthesis allowed for trouble-free removal of p(4-VP)-magnetic composite microgels from the aqueous environment by an externally applied magnetic field upon completion of their task. (C) 2011 Elsevier Ltd. All rights reserved.
Arsenic (V) Removal With Modifiable Bulk and Nano P(4-Vinylpyridine) Hydrogels: the Effect of Hydrogel Sizes and Quarternization Agents
(Elsevier, 2011) Sahiner, Nurettin; Ozay, Ozgur; Aktas, Nahit; Blake, Diane A.; John, Vijay T.
Macrogels and nanogels (5 x 6 mm and 370 nm dimensions, respectively) based on 4-vinylpyridine (p-(4VP)) were prepared using redox and microemulsion techniques. The p(4-VP)-based materials were quaternized with HCl/alkyhalides having different chain lengths to tune the charges (macro and nanogels) and size of nanogels. By developing positive charge on the p(4-VP) materials, they behaved as ion exchangers and used in removal of As(V) from aqueous environments. The prepared p(4-VP) materials were also rendered responsive to magnetic field by in situ incorporation of magnetic metal nanoparticles inside macro p(4-VP) hydrogels and by encapsulation of separately prepared magnetic ferrites by nanosized p(4-VP) particles. Nanoparticles quaternized with HCl (p(4-VP)-HCl) (1 g) removed over 95% of As(V) from a stock solution (10 mg L-1 1000 mL) in 15 min whereas bulk hydrogels removed >82% of the As(V) from an equivalent solution in similar to 12 h. Parameters effecting the As(V) removal, including pH, temperature and ionic strength, were also investigated. The synthesized magnetic p(4-VP) composites could be reused after elution with NaOH and regeneration with quaternization agents; these procedures were facilitated using an externally applied magnetic field. The Langmuir and Freundlich adsorption isotherms were also applied to study the removal of As(V) from aqueous environments. (C) 2011 Elsevier B.V. All rights reserved.
Betaine Microgel Preparation From 2-(methacryloyloxy) Ethyl] Dimethyl (3-Sulfopropyl) Ammonium Hydroxide and Its Use as a Catalyst System
(Elsevier, 2015) Ajmal, Muhammad; Demirci, Sahin; Siddiq, Mohammad; Aktas, Nahit; Sahiner, Nurettin
We demonstrate the synthesis of poly(sulfobetain methacrylate) (p(SBMA)) hydrogels of micro dimensions by inverse suspension polymerization of a zwitterionic monomer 2-(methacryloyloxy) ethyl] dimethyl (3-sulfopropyl) ammonium hydroxide (SBMA). The prepared microgels were used as microreactors for the synthesis of nickel (Ni) nanoparticles by in situ reduction of Ni (II) loaded into microgels from an aqueous medium. The prepared microgels and microgel metal nanoparticle composites were characterized by Fourier Transformation Infrared (FT-IR) Spectroscopy, Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). Thermal properties of the microgels were studied by thermal gravimetric analysis (TGA). The amount of Ni nanoparticles generated within the microgels was determined by Atomic Absorption Spectroscopy (AAS) after dissolving the Ni nanoparticles to form Ni (II) ions by treating with concentrated hydrochloric acid (5 M HCl). The prepared composites were used as catalysts for the reduction of nitro aromatic compounds such as 4-nitrophenol (4-NP), 2-nitrophenol (2-NP) and 4-nitroaniline (4-NA) and excellent catalytic performances were observed. The effects of temperature and amount of catalyst were also evaluated. A mild activation energy in comparison to the literature was calculated as 35.64 kJ/mol, and very high k p value of 0.42 min(-1) as a function of temperature was estimated for the reduction of 4-NP catalyzed by p(SBMA)-Ni composite catalyst system. (C) 2015 Elsevier B.V. All rights reserved.
Bimetallic Ruthenium-Cobalt Catalyst Supported on Carbon Nanotubes: Synthesis, Characterization, and Application in Electrochemical Sensing of Isoleucine
(Wiley, 2025) Arici, Omruye Ozok; Caglar, Aykut; Najri, Bassam A.; Aktas, Nahit; Kivrak, Arif; Kivrak, Hilal
In this work, a bimetallic Ru-Co catalyst based on carbon nanotubes (Ru-Co/CNT) with a Ru to Co ratio of 95:5 is developed. The catalyst, featuring a total metal loading of 3% on the CNTs, is synthesized using the NaBH4 reduction method. Several analytical analyses are used to detect the properties of the Ru-Co/CNT catalyst. X-ray diffraction (XRD) provides information on crystal structures of the catalysts, high-resolution transmission electron microscopy (HR-TEM) reveals particle size and distribution, inductively coupled plasma mass spectrometry (ICP-MS) measures the elemental composition, and X-ray photoelectron spectroscopy (XPS) use to investigate the chemical oxidation states. In addition, thermal techniques including temperature-programmed reduction (TPR), temperature-programmed oxidation (TPO), and temperature-programmed desorption (TPD) are used to recognize the active sites on the catalyst's surface and the acidity. Then, the Ru-Co/CNT catalyst is applied as a sensor for isoleucine amino acid for the first time. It shows high performance with these parameters, sensitivity (0.002 mA cm-2 mm), LOD - limit of detection (0.04 mu m), and LOQ - limit of quantification (0.12 mu m). Moreover, the interferences of common serum blood including (D-glucose, uric acid, ascorbic acid, and L-tryptophan) are studied. The findings indicated that the sensor is applicable to work in complex biological systems.
Biochar-Embedded Soft Hydrogel and Their Use in Ag Nanoparticle Preparation and Reduction of 4-Nitro Phenol
(Taylor & Francis As, 2013) Sahiner, 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.
Biocompatible and Biodegradable Poly(Tannic Acid) Hydrogel With Antimicrobial and Antioxidant Properties
(Elsevier, 2016) Sahiner, Nurettin; Sagbas, Selin; Sahiner, Mehtap; Silan, Coskun; Aktas, Nahit; Turk, Mustafa
A novel resourceful bulk poly(Tannic Acid) (p(TA)) hydrogel was prepared by crosslinking TA molecules with an epoxy crosslinker, trimethylolpropane triglycidyl ether (TMPGDE), in an autoclave at 90 degrees C for 2 h. The obtained p(TA) hydrogels were in disk form and have highly porous morphology. The swelling characteristics of p(TA) hydrogels were investigated in wound healing pH conditions of pH 5.4, 7.4, and 9 at 37.5 degrees C, and the hydrogels showed good swelling and moisture content behavior. Especially, p(TA) hydrogels were found to be sensitive to pH 9 with 1669% maximum swelling. P(TA) hydrogels were completely degraded at pH 9 hydrolytically in 9 days. Total phenol contents and the effects of scavenging ABTS radicals of degraded p(TA) hydrogels at pH 5.4, 7.4, and 9 were evaluated and calculated in terms of gallic acid equivalent and trolox equivalent antioxidant capacity, respectively, and found to be very effective. Moreover, degraded p(TA) hydrogels display strong antimicrobial behavior against gram positive Staphylococcus aureus, Bacillus subtilis, gram negative Pseudomonas aeruginosa bacteria strains and Candida albicans fungus strain. The WST-1 results indicated that bulk p(TA) hydrogels have no cyctotoxicity to the L929 fibroblast cell line in vitro. (C) 2015 Elsevier B.V. All rights reserved.
Carbon Monoxide and Formic Acid Electrooxidation Study on Au Decorated Pd Catalysts Prepared Via Microwave Assisted Polyol Method
(Taylor & Francis inc, 2019) Ulas, Berdan; Kivrak, Arif; Aktas, Nahit; Kivrak, Hilal
In this study, carbon supported Pd monometallic and PdAu bimetallic catalysts are prepared by using microwave assisted polyol method to investigate their carbon monoxide and formic acid electrooxidation activities. These catalysts are characterized by using Scanning Electron Micrsocopy (SEM-EDX) and N-2 adsorption desorption measurements. EDX measurements reveal that catalysts are prepared at desired ratios. The electrochemical characterization was performed via cyclic voltammetry and CO stripping voltammetry. Electrochemical surface area (ECSA) was calculated thanks to CO oxidation peaks. It was reported that CO tolerance and ECSA of the PdAu/C catalysts were higher than that of the Pd/C, attributed to sweeping effect of Au particles in terms of CO adsorption. Furthermore, formic acid electrooxidation activity of these catalysts are examined by using cyclic voltammetry (CV). PdAu/CNT catalyst at prepared at 90:10 Pd:Au ratio exhibited the highest formic acid electroxidation activity. It is clear that PdAu/CNT catalyst is a promising catalyst for CO and formic acid electrooxidation. [GRAPHICS] .
Carbon Nanotube Supported Cdm(S, Se)/Cdte Anode Catalysts for Electrooxidation of Glucose in Alkaline Media
(Wiley-v C H verlag Gmbh, 2023) Caglar, Aykut; Kivrak, Hilal; Aktas, Nahit
The sequential sodium borohydride (SBH, NaBH4) reduction method was utilized to prepare the 0.1 % CdSe/CNT, 0.1 % CdS/CNT, 0.1 % (CdS-CNT)/CdTe, and 0.1 % (CdSe-CNT)/CdTe catalysts. The XRD, SEM-EDS, TEM, and XPS analyses were used to characterize the catalysts. The electrochemical measurements were examined by cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS) analyses for glucose electrooxidation. The characterization analyses revealed that the desired structure was formed on the support material. The electrochemical analysis results indicated that the 0.1 % (CdSe-CNT)/CdTe catalyst has higher catalytic activity, stability, and resistance compared to other catalysts with a specific activity of 2.4 mA cm(-2).
Catalytic Performance of Boron-Containing Magnetic Metal Nanoparticles in Methylene Blue Degradation Reaction and Mixture With Other Pollutants
(Elsevier, 2021) Meydan, Engin; Demirci, Sahin; Aktas, Nahit; Sahiner, Nurettin; Ozturk, Omer Faruk
The catalytic effects of metal nanoparticles (MNPs) synthesized in sodium bis(2-ethylhexyl) sulfosuccinate (AOT) microemulsion system by using M(II) salts (M = Fe, Co, Ni) and NaBH4 reducing agent on methylene blue (MB) degradation reaction were investigated. It was determined that Co-MNPs gave the best catalytic activity among them. Influence of the reaction parameters e.g., reaction time, temperature, the size of catalyst and the MNP types on the catalytic performance were studied. It was found that 37 +/- 6 nm Co-MNPs revealed the best catalytic activity in all studies. The best activation parameters were calculated as 13.6 +/- 1.1 kJ mol(-1) and Delta H = 10.7 +/- 1.0 kJ mol(-1) and Delta S = -87.9 +/- 5.4 J mol(-1) K-1. The activity % of Co-MNPs was calculated as 85.4 after 30 days on the shelf life study. The reusability studies were carried out and the activity of Co-MNPs at the 5th reuse was calculated as 70 +/- 5%. Finally, the catalytic activity of Co-MNPs was investigated inside equal volumes of single and multiple solution mixtures containing MB, 4-Nitrophenol (4-NP) and Eosin Y (EY). In the examinations, it was observed that the nanocatalyst was effective as a reducing agent in all equal amount solutions (MB/4-NP, MB/EY, 4-NP/EY, and MB/4-NP/EY). And also, TOF (mole of MB/4-NP/EY) (mol catalyst.min)(-1) values of catalytic activities were also calculated.
Characterization of P(Pmo), P(Lo) and P(Ro) Organoparticles, Their Bioactivity Properties and Their Effect on Pancreatic Cancer Capan-1 Cell
(Elsevier Science Sa, 2023) Alpaslan, Duygu; Turan, Abdullah; Dudu, Tuba Ersen; Bozer, Busra Moran; Aktas, Nahit; Turk, Mustafa
For the first time in the literature, p (PmO), p (LO) and p (RO) organo-particles were synthesized from Peppermint oil, Lemon oil and Rose oil. Of the organo-particles L-929 cell line viability/cytotoxicity and anticancer effect against Capan-1 pancreatic cancer cell line were investigated. p (PmO), p (LO) and p (RO) organoparticles were featured by thermogravimetry (TGA), Fourier Transform Infrared Spectroscopy (FTIR), Scanning electron microscope (SEM), Particle size (DLS), and particle charge (zeta potential, Zeta) analyses. Antioxidant, biocompatible, and antimicrobial activities and in vitro cytotoxicity specialties were investigated. In studies on Capan-1 and L-929 cell lines, it was observed that p (PmO), p (LO) and p (RO) organo-particles were effective on L-929 fibroblast cell line on Capan-1 pancreatic cancer cell line. In addition, it was observed that p (PmO), p (LO) and p (RO) organo-particles were not toxic in L-929 cell lines at high doses. When the Capan-1 cell line MTT analysis results of p (PmO), p (LO) and p (RO) organo-particles were examined, a difference was observed between cell viability rates and apoptosis and necrosis values. The highest % apoptosis rate was observed in the p (RO) organo particle.
Coll 246-Hyaluronic Acid Hydrogel Particles With Micron and Nano Dimensions and Their Applications in Drug Delivery
(Amer Chemical Soc, 2009) Ilgin, Pinar; Ozay, Hava; Aktas, Nahit; John, Vijay T.; Blake, Diane A.; Ayyala, Ramesh S.; Sahiner, Nurettin
Coll 490-Colloidal P(4-Vp) Particles and Composites for Biomedical Application
(Amer Chemical Soc, 2009) Ozay, Ozgur; Aktas, Nahit; Dulger, Basaran; Silan, Coskun; John, Vijay T.; Sahiner, Nurettin