Chemistry / Kimya

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  • Book Part
    Citation - Scopus: 3
    Tissue Engineering Applications of Marine-Based Materials
    (Springer, 2022) Polat, Hürriyet; Zeybek, Nuket; Polat, Mehmet
    Tissue engineering is a promising approach in replacing or improving tissues lost or has become nonviable due to disease or trauma by the use of scaffold materials by combining engineering and biochemical/physicochemical methods. Its purpose is to create suitable matrices that support cell differentiation and proliferation toward the formation of new and functional tissue. Marine-based natural compounds are potential scaffold feedstock material in tissue engineering owing to their biocompatibility and biodegradability while providing excellent biochemical/physicochemical properties. Numerous application areas and various fabrication routes techniques described in the literature attest to the importance of these materials in tissue regeneration. This review has been carried to merge the information from a large number of studies on the marine-based scaffold materials in tissue engineering into a coherent summary. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022.
  • Conference Object
    Citation - WoS: 1
    Citation - Scopus: 1
    Biomimetic Peptide-Conjugated Membranes for Developing an Artificial Cornea
    (IEEE, 2022) Sunal, Gülşah; Pulat, Günnur; Akgün, İsmail Hakkı; Güven, Sinan; Yıldız, Ümit Hakan; Karaman, Ozan; Horzum, Nesrin
    The corneal endothelium is composed of a single layer of specialized endothelial cells, protecting, and nourishing the inner surface of the cornea. Corneal endothelial cells do not proliferate after birth and their number decrease with age. Trauma, inflammation, or surgical intervention can cause cell loss. When damage is extensive and the density of corneal endothelial cells decreases to a critical level, it results in corneal edema and vision loss. Besides them, when corneal endothelium has irreversible damage, the only treatment way is corneal transplantation. But there are some drawbacks such as finding donors, immune reactions, and the number of patients waiting on the transplantation lists for years. Tissue engineering approaches can provide promising alternatives for the regeneration of corneal endothelium tissue. Peptides can be used to modify and functionalize the scaffolds, allowing for the production of bioactive and biomimetic surfaces. Peptide-modified scaffold surfaces might direct and enhance the behaviors of cells. In this study, the aim was to functionalize the polycaprolactone (PCL) membranes with tissue-specific peptides and to characterize the peptide-conjugated membranes by Fourier-Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and X-ray Photoelectron Spectroscopy (XPS) analysis. The synthesized peptides were successfully conjugated on the PCL biomembranes.
  • Article
    Extraction and Characterization of Pectin From Fresh Globe Artichoke and Canned Artichoke Waste
    (Gıda Teknolojisi Derneği, 2017) Ceylan, Çağatay; Bayraktar, Oğuz; Atçı, Erhan; Sarrafi, Şahin
    The pectin contents of fresh globe artichoke (stem, receptacle, and bract) and waste of artichokecanning industry were investigated. The highest pectin amount was found in the stem part of freshglobe artichoke (6.42%) with the highest amount of anhydrogalacturonic acid (AGA) and anhydrouronicacid (AUA) content. The pectin yields of receptacle and bract parts were found to be 5.31 and 4.55%,respectively. The pectin yield from the industrial waste was the lowest, 4.43%. The highest ash content(5.65 %) along with the lowest anhydrouronic acid amount (73.28%) indicated the lowest purity for theindustrial waste. The degrees of esterification for the pectin obtained from the stem, receptacle andbract parts were 55.26%, 52.26%, and 56.17%, respectively indicating the presence of high methyl-esterified(HM) pectin. The pectin from the industrial waste had the lowest degree of esterification (46.02%). TheFTIR results indicated that acid processing affected the structural properties of pectin from the industrialwaste with higher methoxyl content and esterification degree.
  • Article
    Citation - WoS: 8
    Citation - Scopus: 7
    Engineered Silica Nanoparticles Are Biologically Safe Vehicles To Deliver Drugs or Genes To Liver Cells
    (Elsevier Ltd., 2021) Tüncel, Özge; Kahraman, Erkan; Bağcı, Gülsün; Atabey, Neşe; Özçelik, Serdar
    Engineered silica nanoparticles (SiNP) are emerging materials for medical applications. Evaluating biological responses of specific cells treated with engineered silica nanoparticles is however essential. We synthesized and characterized the physicochemical properties of silica nanoparticles with two different sizes of 10 and 100 nm (10SiNP and 100SiNP) dispersed in cell culture medium. HuH-7, an epithelial-like human hepatoblastoma cell line and SK-HEP-1, a liver sinusoidal endothelial cell line (LSEC) are employed to evaluate their biological responses for the SiNP treatment. Primary human lymphocytes are used to assess genotoxicity recommended by OECD guidelines while erythrocytes are used to assess hemolytic activity. The engineered silica nanoparticles are not able to produce radical species, to alter the mitochondrial membrane potential, and induce any adverse effects on cell proliferation. The colony formation ability of HuH-7 hepatoblastoma cells was not affected following the SiNP treatment. Furthermore, SiNPs do not induce hemolysis of red blood cells and are not genotoxic. These findings suggest that SiNPs regardless of the size, amount, and incubation time are biologically safe vehicles to deliver drugs or genes to the liver. © 2020 Elsevier B.V.
  • Article
    Nonlinear Inorganic Optical Materials
    (Ege Üniversitesi, 1999) Topaloğlu, Işıl
    Ticari olarak uygulamaları bulunan nonlinear optik materyallerin geliştirilmesi için yapılmakta olan çalışmalar özellikle 1980 yılından sonra artış göstermiştir. Bu amaçla incelenen sistemler arasında inorganik kristaller, yarı iletkenler, organometalik bileşikler, organik kristalin monomerler, ve delokalize $\Pi$ elektronları içeren uzun zincirli polymerler Informasyon işlemlerinde optik çevirme, telekominikasyon, optoteknoloji, ve optik frekans çevirme amaçlı olarak çok yaygın olarak kullanılmaktadır. Bu derleme makalesinde nonlinear optik özellik gösteren inorganik bileşikler hakkında kısa bilgi verilmiştir.
  • Conference Object
    Effect of Some Physical, and Chemical Variables on Flocculation and Sediment Behaviour
    (A.A. Balkema Publishers, 2000) Polat, Hürriyet; Polat, Mehmet; İpekoğlu, Üner
    Effect of some chemical and physical variables on the settling rate, final sediment height, sediment viscosity and supernatant turbidity of a clay sample was studied using various polyacrylamide type flocculants. Increasing flocculant concentration significantly increased both the settling rate and sediment viscosity. More importantly, changes in the final sediment, height, hence the packing density, was minimal for all the conditions tested once the sediment was allowed to consolidate. Also, the mode of addition of the polymer, at once or continuous, did not seem to affect any of the parameters measured. Conditioning time seemed to alter the settling rate at low polymer concentrations, but had no effect at high polymer concentrations. However, increasing the conditioning time caused a decrease in the sediment viscosity. Different types of the polyacrylimides generated different settling rates at a given concentration, but the final sediment height was nearly independent of polymer type.
  • Conference Object
    Labeling of Gly-Gly With Technetium-99m and the Assessment of It's Radiopharmaceutical Potential
    (Springer Verlag, 2001) Taner, M.S.; Özdemir, Durmuş; Köseoğlu, K.; Argon, M.; Dirlik, A.; Duman, Y.
    [No abstract available]
  • Conference Object
    Use of Ion Flotation To Remove Copper From Waste Waters
    (2006) Erdoğan, Demet; Polat, Hürriyet; İpekoğlu, Üner
    Flotation studies were carried out to investigate the removal of copper from wastewaters. Various parameters such as pH, surfactant and frother concentrations and airflow rate were tested to determine the optimum flotation conditions. Sodium dodecyl sulfate and Hexadecyltrimethyl ammonium bromide were used as collectors. Recoveries as high as 90% could be to obtained under optimum conditions.
  • Book Part
    Citation - Scopus: 6
    Recent Advances in Chitosan-Based Systems for Delivery of Anticancer Drugs
    (Springer, 2020) Polat, Mehmet; Polat, Hürriyet
    Problems in transporting drug molecules to tumor sites in required dose or constitution lead to low efficacy and significant side effects. Shielding the drug molecules in micelles, liposomes, or nanoparticles is a major line of investigation to improve chemotherapeutic treatment. Though compatibility for proper envelopment of the drug and timely release at the tumor site are required of such a carrier, protecting its own physicochemical and morphological integrity during transport is another precondition. Because of its superior polymerization capability, biocompatibility, pH dependence, and charging characteristics, chitosan has been in the forefront of potential drug carriers. Numerous synthesis routes for chitosan-based nanocarriers have been suggested to the extent that a search of the literature published since 2000 with the keywords “novel + nano + chitosan” in the title results in 527 articles, indicating the bewildering quality and quantity of the new information. This review was carried out not only to peruse this large amount of work on chitosan-based anticancer drug delivery but also to extract manageable patterns from numerous synthesis routes. The main conclusion is that the synthesis methods suggested in literature can be combined into two main routes, and the degree of hydrophobicity of the drug determines which route should be followed. © Springer Nature Singapore Pte Ltd. 2019.
  • Book Part
    Citation - Scopus: 8
    The Multiwavelength Uv/Vis Detector: New Possibilities With an Added Spectral Dimension
    (Springer Verlag, 2016) Karabudak, Engin; Cölfen, Helmut
    The multiwavelength (MWL) detector is a new type of absorption detector for AUC. The commercial absorption detector of the Beckman Coulter XLA AUC can only handle a single wavelength per scan with the possibility to scan at maximum 3 wavelengths, whereas MWL-AUC can handle all the wavelengths in the UV/Vis region at one time. The result is impressive since now a full spectral dimension is added to each single scan. In this chapter, we are explaining development history, instrumentation, and future perspective of MWL-AUC.