Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
Browse
7 results
Search Results
Now showing 1 - 7 of 7
Conference Object Citation - WoS: 24Effect of pH and Hydration on the Normal and Lateral Interaction Forces Between Alumina Surfaces(2006) Polat, Mehmet; Sato, Kimiyasu; Nagaoka, Takaaki; Watari, KojiNormal and lateral interaction forces between alumina surfaces were measured using Atomic Force Microscopy-Colloid Probe Method at different pH. The normal force curves exhibit a well-defined repulsive barrier and an attractive minimum at acidic pH and the DLVO theory shows excellent agreement with the data. The normal forces are always repulsive at basic pH and the theory fails to represent the measurements. Lateral forces are almost an order of magnitude smaller in the basic solutions. These differences, which have important implications in the study of stability and rheology, are attributed to the hydration of the alumina surface at basic pH. © 2013 Elsevier B.V., All rights reserved.Book Part Citation - Scopus: 3Tissue Engineering Applications of Marine-Based Materials(Springer, 2022) Polat, Hürriyet; Zeybek, Nuket; Polat, MehmetTissue 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 Solution of the Non-Linear Poisson Boltzmann Theory for the General Case of Dissimilar Double Layers(2006) Polat, MehmetCalculation of the surface potentials, surface charges or electrostatic pressure for interacting colloidal particles is exceedingly important in mineral processing, environmental engineering, ceramic sciences, etc. Such calculations require solving the non-linear Poisson-Boltzmann theory at each plate separation. Though approximate analytical solutions of this theory are available for simplified cases, a general, but compact analytical solution is yet to be developed. A solution with no restrictions on surface potentials or charges is developed in this paper. The expressions developed are straightforward and require as input only the surface potentials at infinite separations.Book Part Citation - Scopus: 6Recent Advances in Chitosan-Based Systems for Delivery of Anticancer Drugs(Springer, 2020) Polat, Mehmet; Polat, HürriyetProblems 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.Conference Object Citation - Scopus: 3Characterization of Polysulfone Based Hemodialysis Membranes by Afm(Elsevier Ltd., 2012) Uz, Metin; Yaşar Mahlıçlı, Filiz; Polat, Mehmet; Alsoy Altınkaya, SacideMost of the hemodialysis membrane materials are hydrophobic in nature and allow protein adsorption on the surface easily due to hydrophobic interaction between membrane surface and protein molecules when in contact with blood. Adsorbed proteins can affect platelet and leukocyte adhesion, and modulate the response of plasmatic reactions followed by the activation of different defense systems in blood (Sun et al. 2003).Article Citation - WoS: 98Citation - Scopus: 108Capacity and Mechanism of Phenol Adsorption on Lignite(Elsevier Ltd., 2006) Polat, Hürriyet; Molva, Murat; Polat, MehmetA raw lignitic coal from Soma, Turkey was investigated to determine its potential as an adsorbent for phenol removal from wastewaters. Kinetic batch tests demonstrated that phenol could be completely removed from solution given sufficient solids loading and reaction time. The adsorption capacity of 10 mg/g obtained with the lignite is low compared to those achievable with activated carbons (around 300 mg/g). However, when normalized for the surface area, the adsorption capacity was much larger for the lignite (1.3 mg/m2) than that generally observed with activated carbons (0.05-0.3 mg/m2). Hydrogen-bonding of the phenolic -OH with the oxygen sites on the lignite surface is the most likely mechanism for adsorption. Though water molecules also have affinity for the same oxygen sites, lateral benzene ring interactions make phenol adsorption energetically more favorable. Since phenol molecules adsorbed in this fashion would project their benzene rings into solution, formation of a second layer through the action of the dispersive π-π interactions between the benzene rings is very likely. Residual water quality with respect to major elements and heavy metals was within acceptable limits defined by the ASTM standards. Dissolution of organic matter from the lignite was also observed to be negligible.Article Citation - WoS: 198Citation - Scopus: 210Physical and Chemical Interactions in Coal Flotation(Elsevier Ltd., 2003) Polat, Mehmet; Polat, Hürriyet; Chander, SubhashCoal flotation is a complex process involving several phases (particles, oil droplets and air bubbles). These phases simultaneously interact with each other and with other species such as the molecules of a promoting reagent and dissolved ions in water. The physical and chemical interactions determine the outcome of the flotation process. Physical and chemical interactions between fine coal particles could lead to aggregation, especially for high rank coals. Non-selective particle aggregation could be said to be the main reason for the selectivity problems in coal flotation. It should be addressed by physical (conditioning) or chemical (promoters) pretreatment before or during flotation. Although the interactions between the oil droplets and coal particles are actually favored, stabilization of the oil droplets by small amounts of fine hydrophobic particles may lead to a decrease in selectivity and an increase in oil consumption. These problems could be remedied by use of promoters that modify the coal surface for suitable particle-particle, droplet-particle and particle-bubble contact while emulsifying the oil droplets. The role of promoters may be different for different types of coals, however. They could be employed as modifiers to increase the hydrophobicity of low rank coals whereas their main role might be emulsification and aggregation control for high rank coals. In this paper, a detailed description of the various phases in coal flotation, their physical and chemical interactions with each other in the flotation pulp, the major parameters that affect these interactions and how these interactions, in turn, influence the flotation process are discussed.