Makale Koleksiyonu
https://hdl.handle.net/11491/3448
Article Colleciton2024-03-28T08:24:00ZAsidik ortamda paslanmaz çeliğin korozyonuna yeşil inhibitör olan Nikotinamidin etkisi
https://hdl.handle.net/11491/8692
Asidik ortamda paslanmaz çeliğin korozyonuna yeşil inhibitör olan Nikotinamidin etkisi
Asan, Gülden
Paslanmaz çelik tüm dünyada en çok kullanılan metallerden birisidir. Paslanmaz çeliğin asidik ortamda korozyon direnci düşük olduğu için ve endüstride asit kullanımı çok yaygın olduğundan paslanmaz çeliğin korozyondan korunması önem arz etmektedir. Bu çalışmada inhibitör olarak çevre dostu olan nikotinamid bileşiği paslanmaz çeliğin korozyondan korunmasında kullanıldı. Çalışmada öncelikle paslanmaz çeliğin 0,1 M HCl asit çözeltisinde elektrokimyasal davranışını belirlemek için dönüşümlü voltametri tekniği kullanıldı. Daha sonra 0,1 M HCl asit çözeltisinde Tafel polarizasyon yöntemi nikotinamid inhibitörü olmadığında, 500 ppm, 750 ppm ve 1000 ppm nikotinamid varlığında paslanmaz çeliğin korozyon davranışını tayin etmek için uygulandı. Bu 3 farklı derişimde inhibitör 0, 15, 30, 45 ve 60 dakikalık sürelerde bekletilerek her bir derişim için optimum süre tayini yapıldı. En yüksek inhibitör etkinliği 1000 ppm nikotinamid derişiminde 15 dakikalık bekletme süresinde % 96,8, süre kısıtlaması olmadığında 500 ppm nikotinamid derişiminde 60 dakikalık bekletme süresinde inhibitör etkinliği %96,6 olarak bulundu. Elde edilen sonuçlar gösterdi ki nikotinamid, paslanmaz çeliğin korozyondan korunmasında etkin bir şekilde kullanılabilir ve çevre dostu olması sebebiyle de korozyondan korunma sağlanırken çevreye ve canlılara zarar verilmemiş olur.; Stainless steel is the most used metal all over the world. Since the corrosion resistance of steel is low in acidic medium and the use of acid in industry is very common, it is important to protect the steel from corrosion. In this study, the environmentally friendly nicotinamide compound was used as an inhibitor to protect steel from corrosion. In the study, firstly, the cyclic voltammetry technique was used to determine the electrochemical behavior of the steel in 0.1 M HCl acid solution. Then, Tafel Polarization Method in 0.1 M HCl acid solution was applied to determine the corrosion behavior of steel in the absence of nicotinamide inhibitor, in the presence of 500 ppm, 750 ppm and 1000 ppm nicotinamide. The optimum time was determined for each concentration by keeping the inhibitor at these 3 different concentrations for 0, 15, 30, 45 and 60 minutes. The highest inhibitory efficiency was found to be 96.8% in 1000 ppm nicotinamide concentration in 15 minutes holding time, and 96.6% at 500 ppm nicotinamide concentration in 60 minutes holding time in the absence of time limitation. The results obtained showed that nicotinamide can be used effectively in the protection of stainless steel from corrosion, and due to its environmental friendliness, corrosion protection is provided while not harming the environment and living things.
2023-01-01T00:00:00ZTherapeutic Effects of Newly Synthesized Boron Compounds (BGM and BGD) on Hepatocellular Carcinoma
https://hdl.handle.net/11491/7359
Therapeutic Effects of Newly Synthesized Boron Compounds (BGM and BGD) on Hepatocellular Carcinoma
Koldemir Gündüz, Meliha; Bülter Bolat, Melda; Kaymak, Güllü; Berikten, Derya; Köse, Dursun Ali
Boron has an important potential for facilitating biological activity and for use in pharmaceutical drug design. Boron glycine monoester (BGM) and boron glycine diester (BGD) compounds containing boron atoms were synthesized and investigated their cytotoxic, oxidative stress, and antimicrobial activities on the HepG2 cancer cell line. The cytotoxic activity of newly synthesized boron compounds on hepatocellular carcinoma was determined by the MTT method for 48 h. Antioxidant (CAT, GSH), lipid peroxidation (MDA), and enzyme activity (ACP, ALP) analyses were determined by spectrophotometric methods in HepG2 cells. Antimicrobial activity was determined by the disk diffusion method. After 48 h of BGM and BGD application to HepG2 cells, we found the IC50 values as 9.9 mM and 24 mM, respectively. While CAT and ACP enzyme activities decreased in all groups compared to the control, ALP enzyme activity did not change in the BGM group but increased in the BGD group. It was determined that the GSH level did not change in all groups, while the MDA level increased. It has been stated that these IC50 doses of BGM and BGD have antibacterial effects on Staphylococcus aureus ATCC 29213 and Escherichia coli ATCC 25922. Newly synthesized boron compounds, particularly BGM, with their cytotoxic, oxidative stress, and antimicrobial effects, could provide a new therapeutic approach for the treatment of hepatocellular carcinoma.
2021-01-01T00:00:00ZWater-soluble polymeric particle embedded cryogels: Synthesis, characterisation and adsorption of haemoglobin
https://hdl.handle.net/11491/7340
Water-soluble polymeric particle embedded cryogels: Synthesis, characterisation and adsorption of haemoglobin
Erol, Kadir; Bolat Bülter, Melda; Köse, Dursun Ali; Kaplan Can, Hatice
Making cryogels, which are among today's accepted adsorbents, more functional with different methods, has been one of the subjects spent overtime. In this study, water-soluble poly(maleic anhydride-alt-acrylic acid) polymer embedded in poly(2-hydroxyethyl methacrylate) cryogels. Copper ionswere then immobilised to this structure, and this polymer was used for adsorption of haemoglobin from aqueous systems. Adsorption interaction was carried out on an electrostatic basis, and approximately 448.62 mg haemoglobin/g polymer adsorption capacity value was obtained. Itwas found that the same material hasmanaged to maintain its adsorption ability by 90.3% even after the use of it five times in the adsorption/desorption cycle. The adsorption interaction was determined to be appropriate for the Langmuir model by isotherm studies. The change in Gibbs free energy value was calculated as -2.168 kJ/mol.
2021-01-01T00:00:00ZSynthesis, characterization and antibacterial application of silver nanoparticle embedded composite cryogels
https://hdl.handle.net/11491/7057
Synthesis, characterization and antibacterial application of silver nanoparticle embedded composite cryogels
Erol, Kadir; Bolat Bülter, Melda; Tatar, Demet; Nigiz, Cengiz; Köse, Dursun Ali
Water treatment applications; they consist of processes that desalination, softening, removals of dissolved organic matter, color, particle and microorganism. In traditional treatment processes, microorganisms cause thick film layer on the membrane to be used and not enough treatment. Silver nanoparticles (AgNPs), known to stop bacterial growth due to their superior antibacterial properties even at low concentrations due to their contact with microorganisms, are used for water disinfection. Membrane production with a combination of AgNPs and polymers has started to attract attention in recent years due to advanced optics, conductivity and antibacterial properties. The ability of AgNP to exhibit its antibacterial effect depends on the property of this material to be homogeneously dispersed in the polymer. In this study, Poly(2-hydroxyethyl methacrylate-glycidyl methacrylate), Poly(HEMA-GMA), cryogels were synthesized as solid support. In order to gain antibacterial properties to synthesized cryogels, AgNPs of different sizes were embedded in cryogels. These structures have been used as a kind of antibacterial filter in the purification of water obtained from natural sources used as drinking and using water in the local region. Particle Size analysis was used to determine the size of synthesized AgNPs. Swelling test, Scanning Electron Microscopy (SEM), Elemental Analysis, Fourier Transform Infrared Spectroscopy (FT-IR), and surface area (BET) analysis were performed for characterization of cryogels. (C) 2019 Elsevier B.V. All rights reserved.
2020-01-01T00:00:00Z