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    Öğe
    Equilibrium and kinetic studies of copper (II) ion uptake by modified wheat shells
    (Desalination Publ, 2012) Aydin, Haluk; Yerlikaya, Cigdem; Uzan, Serhat
    Natural adsorbents such as shells of unmodified wheat (RW), and modified wheat (MW) were assessed for Cu(II) adsorption from aqueous solutions. The removal of Cu(II) by these adsorbents from aqueous solution was investigated by using several parameters such as modificiation, contact time, temperature and pH. The extent of Cu(II) removal increased with increasing contact time, temperature and pH and also with modification by Reactive Orange 122 of adsorbent. The experimental data were analysed by the Langmuir and Freundlich models of adsorption. It was found that the Freundlich equation fits better than the Langmuir equation. In addition, the adsorption data obtained at different temperatures of Cu(II) by adsorbents were applied to pseudo first-order, pseudo second-order and Weber-Morris equations, and the rate constants of first-order adsorption (k(1)), the rate constants of second-order adsorption (k(2)) and diffusion rate constants (k(3)) at these temperatures were calculated, respectively. The rates of adsorption were found to conform to pseudo second-order kinetics with good correlation (R-2 >= 0.989). The data obtained from adsorption isotherms at different temperatures were used to calculate some thermodynamic quantities such as free energy of adsorption (Delta G degrees), enthalpy (Delta H degrees), and entropy (Delta S degrees). It is found that Delta G degrees is negative, indicating that the nature of adsorption process for Cu(II) is spontaneous. The positive value of Delta H degrees indicates that the adsorption of Cu(II) onto adsorbents is an endothermic process. The positive value of Delta S degrees reflects the affinity of the adsorbent for Cu(II). As a result, the present work indicates that the wheat shells MW chemically by Reactive Orange 122, possess more efficiency in adsorbing Cu(II) ions than the unmodified one (RW).
  • Küçük Resim
    Öğe
    Homo kiral BİS (amino alkol) okzalamitlerin geçirgenlik arttırıcı özellikli sıvılarla jelleştirilmesi ve ilaç taşıyıcı sistem olarak kullanımları
    (2016) Uzan, Serhat; Aydın, Haluk; Hoşgören, Halil
    İlaç depo sistemleri geliştirmek ve non-steroidal ilaç molekülleri için yeni dermal ve lokal ilaç veriliş araçları olarak tanımlanan organik sıvılarda jelleşebilen aminoalkol bazlı bis(aminoalkol) okzalamitler (sırasıyla, 1-6:aminoalkol=leusinol, ileusinol, valinol, fenilalaninol, fenilglisinol, 2-amino-1-bütanol), iyi bilinen LMWG (Düşük Mol Kütleli Jelatör)'leridir. Kozmetik endüstrisinde kullanılan, etil laurat, etil miristat, etil palmitat, izopropil laurat, izopropil miristat, izopropil palmitat gibi farklı zincir uzunluklarına sahip FAE (yağ asidi etil ve izopropil esterleri)'ler, biyouyumlu organik jelleştirici sıvılar olarak bu çalışmada seçilmiştir. İbuprofen (Ib) model ilaç olarak, bu supramoleküler jellerin içine hapsedildi. Supramoleküler organojellerdeki ibuprofen moleküllerinin salım davranışı, UV-Vis spektroskopisi kullanılarak incelendi. Ib'nin salım davranışlarına; organojelatör ve ilaç konsantrasyonu, ortamın pH'sı ve çözücü (farklı FAE'leri) doğasının etkisi durağan şartlar altında araştırıldı. Sonuçlar supramoleküler organojellerde Ib'nin yüzde salımının, jelatör konsantrasyonunun artışı ile kısmen azaldığını göstermiştir. Ayrıca, Ib içeriğinin artması ile salımı hızı artmıştır. Farklı pH değerlerine sahip ortam olarak kabul edilen tamponlarda da Ib'nin salım davranışının farklı olduğu bulunmuştur. Salım kinetikleri incelemeleri, Ib'nin salım davranışının farklı denklemlere ve Fick'e uymayan (Anomalous transport) modele dahil olan salım mekanizması ile uyum içinde olduğunu göstermiştir. Bu gözlemler non-stereoidal ilaç moleküller için bis(aminoalkol) okzalamit jellerinin ilaç veriliş araçları olabileceğini ve böyle sistemlerin salım profillerine, jelatör-FAE kombinasyonunun doğru seçimi ile ince ayar yapılabileceğini de göstermiştir. Anahtar Kelimeler: Bis(aminoalkol) okzalamitler, düşük molekül kütleli organojelatörler, ilaç salım, ilacın hapsedilmesi, Ibuprofen (NSAID).
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    Öğe
    Improvement of Synthesis and Dielectric Properties of Polyurethane/Mt-QASs+ (Novel Synthesis)
    (Springer, 2016) Baysal, Gulay; Aydin, Haluk; Hosgoren, Halil; Uzan, Serhat; Karaer, Hatice
    Polyurethane-based nanocomposites were prepared and their dielectric properties were characterized. Polyurethane (PU) composites were prepared with different organoclay content (1, 3, 5, and 10 wt% for all cases). The composites included quaternary ammonium salts such as 1-methyl-di-octyl-1 phenyl ammonium iodide (QAS-1), 1-methyl-di-nonyl-1 phenyl ammonium iodide (QAS-2), and 1-methyl-di-dodecyl-1 phenyl ammonium iodide (QAS-3) which were newly synthesized for modification of Na+-montmorillonite. Addition of aluminum silicate enhanced the dielectric properties at a constant concentration. Dielectric constants of nanocomposites compounded with 3 %- and 5 %-organoclay were close in value. The characterization of PU/organoclay composites was carried out using Fourier transform infrared and X-ray diffraction.
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    Öğe
    The interaction methylene blue and glutathione-S-transferase purified from human erythrocytes
    (Springer Heidelberg, 2020) Uzan, Serhat; Acay, Hilal; Baran, M. Firat; Bilden, Alican; Aygun, Husamettin
    It is known that textile dyes have various risks on human health. Glutathione-S-transferase enzymes play a critical role in the detoxification of xenobiotics in living systems. This study aimed to examine the interaction of methylene blue with human erythrocyte glutathione-S-transferase purified in one step. Human erythrocyte glutathione-S-transferase was purified with approximately 750-fold purification and 30% efficiency by glutathione agarose affinity chromatography. The results showed that the enzyme was inhibited by methylene blue with an IC(50)value of 1.40 mmol/L. The Ki constant of methylene blue was 1.17 mmol/L. The Lineweaver-Burk graph of the methylene blue showed that the type of inhibition was compatible with mixed type inhibition. A new third spot was also detected by thin-layer chromatography. Furthermore, the cytotoxicity of methylene blue on human erythrocytes was evaluated and it was found that the haemolysis per cent of methylene blue on erythrocytes was approximately 14%.
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    Öğe
    Investigation of Antimicrobial Properties of QASs+ (Novel Synthesis)
    (Maik Nauka/Interperiodica/Springer, 2018) Baysal, Gulay; Aydin, Haluk; Uzan, Serhat; Hosgoren, Halil
    Quaternary ammonium salts (QASs) are bioactive materials known for their antimicrobial effects. However, it is difficult to provide desirable quaternary ammonium salts. Thus, firstly new quarternary ammonium salts which are not in the literature were synthesized and organoclays were prepared with different quarternary ammonium salts content. The organoclays included quaternary ammonium salts such as N,N-di (3-methyl butyl)-N-(1-phenylethyl)-N-methyl ammonium Iodide (QAS-1), N,N-dipentil-N-(1-phenylethyl)-N-methyl ammonium Iodide (QAS-2), and N,N-dihexcyl-N-(1-phenylethyl)-N-methyl ammonium Iodide (QAS-3) which were newly synthesized for modification of Na+-montmorillonite (Na+-Mt) and were characterized by nuclear magnetic resonance spectroscopy (NMR). Synthesized organoclays were characterized by using Fourier transform infrared (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Characterization results proved that the modification is performed with high performance and as seen in the XRD results, the interstratum distances increased considerably and the diffraction angles decreased. The antimicrobial activity of the organoclays against Staphylococcus aureus and Escherichia coli were studied in detail and were obtained much larger inhibition zones than similar studies. QAS-3-Mt organoclay showed the maximum of antimicrobial activity against S. aureus and E. coli. As is known, organoclay comes among the fillers that play the most effective role in the synthesis of composite materials. In this context, the product we have synthesized is unique and can be used for many purposes.
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    Öğe
    Organogels as novel carriers for dermal and topical drug delivery vehicles
    (Pergamon-Elsevier Science Ltd, 2016) Uzan, Serhat; Baris, Deniz; Colak, Mehrnet; Aydin, Haluk; Hosgoren, Halil
    Aminoalcohol based bis-(aminoalcohol)oxalamides (BAOAs) (1,6-amino alcohol=leucinol, isoleucinol, valinol, phenyiglycinol, phenylalaninol and 2-amino-1-butanol) have been explored to develop drug depot systems and illustrated as a novel dermal and topical drug delivery vehicle for non-steroidal anti-inflammatory drug molecules. FAE's (Fatty acid ethyl and isopropyl esters) with different chain lengths, ethyl laurate, ethyl myristate, ethyl palmitate, isopropyl laurate, isopropyl myristate, isopropyl palmitate, have been chosen as they are biocompatible organic fluids used typically in cosmetic industry. Ibuprofen (Ib), acting as a model drug, was entrapped in the supramolecular organogels. The release behavior of Ib molecules in the supramolecular organogels was investigated by using UV-vis spectroscopy. The influence of the organogelator and drug concentration, pH values of the accepting media, and nature of solvent (different FAE's) on the release behavior of Ib was investigated under static conditions. The results indicated that the release rate of Ib from the supramolecular organogels was effectively retarded with an increase of the organogelator concentration. Also, the release rates of Ib increased on increasing the Ib content. Furthermore, the release behavior of Ib was found to be different at various pH values in buffers as accepting media. The study of the release kinetics indicated that the release behavior of Ib was in accord with the Higuchi equation and the diffusion-controlled mechanism involved in the Fickian model. These observations indicate that bis-(aminoalcohol)oxalamides gels may act as delivery vehicles for non-steroidal anti-inflammatory drug molecules and also show that the release profiles for such systems can be fine-tuned by the correct choice of gelator-FAE combination. (C) 2016 Elsevier Ltd. All rights reserved.
  • Küçük Resim
    Öğe
    Organokil hazırlamada yeni kuarterner amonyum tuzlarını modifiye edici olarak kullanma
    (2015) Uzan, Serhat
    Na+- Montmorillonit (Na+-MMT) 2:1 oranında tabakalı bir silikattır. Bir Na+-MMT birimi, iki silisyum tetrahedral tabakası arasında bir oktahedral alimunyum tabakası olacak şekilde meydana gelmiştir. Kil modifikasyonu genellikle organofilik katyonlarla iyon değişim tepkimesiyle yapılır. Kuarterner amonyum tuzları katyonik adsorplananlardır ve organokil hazırlamada en çok kullanılan organik bileşiklerdir. Bu bileşikler amonyak veya aminlerin tam alkilleşme tepkimesiyle sentezlenirler. Kuarterner amonyum tuzlarını içeren katyonik yüzey aktif ajanlar yıllardan beri etkili antiseptik ve dezenfekten olarak bilinen önemli biyositlerdir. Kuarterner amonyum tuzları yüksek antimikrobiyal aktivite gösteren fonksiyonel gruplara sahiptirler. Bu aktiflik, minimum inhibitor derişimi ya da disk difüzyon yöntemiyle karakterize edilir ve özellikle gram-pozitif bakteriler ve mantarlara karşı yüksektir. Bu çalışmada ilkin, Na+-MMT' in modifikasyonu için tam alkilleşme tepkimesiyle farklı kuarterner amonyum tuzları N,N-dihegzil-N-(1-feniletil)-N-metilamonyum iyodür (QAS-1), N,N-dipentil-N-(1-feniletil)-N-metilamonyum iyodür (QAS -2) ve N,N-di(3-metil butil)-N-(1-feniletil)-N-metilamonyum iyodür (QAS -3) sentezlendi. İkinci safhada ise, kuarterner amonyum tuzları (QAS-1, QAS-2 ve QAS-3) ile Na+-MMT den organo montmorillonitler (OMMT-1, OMMT-2 ve OMMT-3) hazırlandı. Modifiyesiz ve modifiyeli materyal FTIR, XRD ve SEM ile kalitatif olarak karakterize edildi. Örneklerin XRD desenlerinden elde edilen sonuçlara göre, kuarterner amonyum tuzlarının tabakalar arasına girmesi sonucu bazal genişliğin artığı doğrulandı.