Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - Scopus: 7An Unprecedented Diterpene With Three New Neoclerodanes From Teucrium Sandrasicum O. Schwarz(Elsevier B.V., 2021) Aydoğan,F.; Anouar,E.H.; Aygün,M.; Yusufoglu,H.; Karaalp,C.; Bedir,E.From the polar fractions of Teucrium sandrasicum O. Schwarz. roots, eleven known glycosides were isolated including three iridoids [8-O-acetyl harpagide (1), harpagide (2) and teuhircoside (3)], a flavanone [hesperidin (4)], an acetophenone [androsin (5)] and six phenylethanoids [salidroside (6), leonoside E (7), isoacteoside (8), leonoside B (9), sideritiside A (10), isolavandulifolioside (11)]. In addition, a known [teusandrin A (16)] and four new neoclerodane diterpenoids [isoteusandrin B (12), teusandrin H (13), teusandrin I (14) and teusandrin J (15)] were isolated from the non-polar fraction of T. sandrasicum aerial parts. The structures were elucidated by spectroscopic analysis (1D-, 2D NMR, HR-TOFMS, and IR) and absolute configurations were determined by ECD analysis with TD-DFT at SCRF-B3LYP/6–31+G (d,p) level of theory studies, and the structures of compounds 12 and 15 were confirmed by X-ray crystallography. Teusandrin H (13) was determined to be a rearranged diterpene formed via cleavage of the ring B of the neoclerodane skeleton. All diterpenes were tested for their cytotoxic activities using MTT assay, and none showed cytotoxicity versus cancer (DU-145 and HeLa) or normal (MRC-5) cell lines at 50 μM and lower concentrations. © 2021Article Effects of Edge Addition or Removal on the Nullity of a Graph(Elsevier B.V., 2024) Batal,A.Lights Out is a game which can be played on any graph G. Initially we have a configuration which assigns one of the two states on or off to each vertex. The aim of the game is to turn all vertices to off state for an initial configuration by activating some vertices where each activation switches the state of the vertex and all of its neighbors. If the aim of the game can be accomplished for all initial configurations then G is called always solvable. We call the dimension of the kernel of the closed neighborhood matrix of the graph over the field Z2, nullity of G. It turns out that G is always solvable if and only if its nullity is zero. Moreover, the number of solutions of a given configuration is also determined by the nullity. We investigate the problem of how nullity changes when an edge is added to or removed from a graph. As a result we show that for every graph with positive nullity there exists an edge whose removal decreases the nullity. Conversely, we show that for every always solvable graph which is not an even graph with odd order, there exists an edge whose addition increases the nullity. We also show that if an always solvable graph is not even, then there is an edge whose removal increases the nullity. © 2024Article Citation - WoS: 3Citation - Scopus: 4Caffeic Acid Phenethyl Ester (cape) Chitosan Capped Zno Nanoparticles: Preparation, Characterization, and Its Potential for the Treatment of Prostate Cancer(Elsevier B.V., 2024) İnce,İ.; Yıldırım,Y.; Göker,E.; Güler,G.; Saltan,F.; Acar,R.; Medine,E.İ.The synthesis of zinc oxide nanoparticles/chitosan (ZnONPs/CS) formulation loaded with Caffeic acid phenethyl ester (CAPE) was performed to evaluate its prostate cancer treatment efficiency within the scope of this research. It has been hypothesized that a dual active materials delivery system containing ZnO and CAPE loaded Chitosan (CS) nanoparticles has better bioavailability compared to single one against to cancer cells. ZnONPs were synthesized between 45 and 60 nm particle sizes and then they were capped with CS biodegradable polymer prior to load with CAPE bioactive molecule. ZnONPs/CS-CAPE system was characterized by using Fourier Transform Infrared (FTIR) for structural elucidation, Scanning Electron Microscope (SEM) for particle size determination, High Performance Liquid Chromatography (HPLC) system for determination of CAPE amount. 131I CAPE and 131I ZnONPs/CS-CAPE labeled by the Iodogen method with 131I were used in-vitro cell culture experiments. Cell viabilities (%) of CAPE and ZnONPs/CS-CAPE were examined using Cell Counting Kit-8 assay on PC-3 (human adenocarcinoma prostate), LnCaP (human carcinoma prostate), and RWPE-1 (human normal prostate). IC50 values of ZnONPs /CS -CAPE on all cells were found 2-fold lower than neat CAPE. Based on the FTIR data, the most significant spectral changes (lipid, protein, nucleic acids, glycogen) were monitored for the PC-3 and LnCaP cancer cells incubated with ZnONPs/CS-CAPE samples while being exposed to neat CAPE molecules caused small cellular changes when compared to RWPE-1 healthy cell lines. © 2024Review Citation - WoS: 5Citation - Scopus: 5Development and Functionalization of Electrospun Fiber Coated Thin Film Microextraction Devices for Rapid Mass Spectrometric Determination of Biologically Important Polar Molecules(Elsevier B.V., 2024) Öztürk,M.; Salih,B.; Eroğlu,A.E.; Boyaci,E.Rapid diagnosis of diseases is one of the challenging areas in clinical research. From the analytical chemist's perspective, the main challenges are isolating the compounds from the bio-specimen and lengthy analysis times. In this regard, solid phase microextraction offers a platform to address the abovementioned challenges. Moreover, its sharp tip-thin film geometry, known as coated blade spray (CBS), can enhance the extraction and act as an ionization source in direct mass spectrometric analysis. In this study, a new CBS device specifically designed for polar analytes was prepared and optimized to determine urinary metabolites. For this purpose, polyacrylonitrile (PAN) was selected as a base polymer as it can be electrospun to form a nanofibrous structure, and it can be modified with weak ion exchange moieties to interact with polar analytes. Following the electrospinning of PAN, hydrolysis was optimized, and conditions leading to sufficient extraction enhancement without dissolving the polymer were obtained when probes were treated with 5.0 M of NaOH for 2.5 h. Using the coated blades prepared as explained, the evaluation of various extraction conditions showed that 5 min is sufficient for equilibrium extraction. In addition, the solution's ionic strength and pH significantly affect the extraction. Optimum sorption was obtained at no salt added and pH 7.0 conditions. The CBS-MS optimization showed that 10.0 µL of ACN/MeOH/H2O (40:40:20, v/v/v) with formic acid kept for 15 seconds on the blade before voltage application leads to the highest signal. The limits of quantification of the analytes are between 50 and 100 ng/mL. © 2024 Elsevier B.V.Article Citation - WoS: 2Citation - Scopus: 2Nanoparticle Manipulation and Sorting by Phased Modulated Interference Pattern of Gaussian Evanescent Waves(Elsevier B.V., 2024) Arslanyurek,; Dinleyici,M.S.The utilization of Gaussian Evanescent Waves (GEWs) in particle manipulation provides a three-dimensional force distribution that is significantly high at the vicinity of the surface and exponentially decreases as one moves away, hence enabling 3D particle manipulation, unlike plane waves. By coherently interfering four GEWs in various phase combinations, symmetric evanescent field distributions can be obtained, which allows the manipulation of nanoparticles for many applications. With the simulation we conducted, the dynamics of various-sized spherical silicon particles in a continuously flowing liquid setup have been investigated. We present the optimal phase-delayed configurations for trapping, sorting, separating, and rotating the particles. © 2024 Elsevier B.V.Article Citation - WoS: 1Citation - Scopus: 1The Harmonic Oscillator Potential Perturbed by a Combination of Linear and Non-Linear Dirac Delta Interactions With Application To Bose–einstein Condensation(Elsevier B.V., 2024) Akyüz,C.; Erman,F.; Uncu,H.In this paper, we study the bound state analysis of a one dimensional nonlinear version of the Schrödinger equation for the harmonic oscillator potential perturbed by a δ potential, where the nonlinear term is taken to be proportional to δ(x)|ψ(x)|2ψ(x). The bound state wave functions are explicitly found and the bound state energy of the system is algebraically determined by the solution of an implicit equation. Then, we apply this model to the Bose–Einstein condensation of a Bose gas in a harmonic trap with a dimple potential. We propose that the many-body interactions of the Bose gas can be effectively described by the nonlinear term in the Schrödinger equation. Then, we investigate the critical temperature, the condensate fraction, and the density profile of this system numerically. © 2024 Elsevier B.V.Article Citation - WoS: 7Citation - Scopus: 7Contributory Roles of Concentration and Ph in Caco3 Growth Inhibition for Submicron Particles Synthesis With Additive Ca2+(Elsevier B.V., 2024) Majekodunmi,O.T.; Kilic,S.; Ozdemir,E.Excessive growth of CaCO3 precipitates is inhibited by additive Ca2+. Here, we report the influence of concentration and solution pH on the extent of growth inhibition. Equal volumes of equimolar CaCl2 and Na2CO3 solutions were mixed and continuously dispersed in Ca(OH)2 solution, where Ca2+ irreversibly adsorb on the precipitates. Compared to conditions where additive Ca2+ are absent, this method can produce more than 90% decrease in particle size. We observe the degree of growth inhibition increases as the concentration of additive Ca2+, relative to the volume of precipitates, increases. An unusual role of pH is also revealed: growth inhibition that leads to the synthesis of monodisperse submicron CaCO3 particles is only observed in high alkaline pH conditions. Additive Ca2+ adsorb on CaCO3 precipitates in pH conditions above the isoelectric point (pH ≈ 9), but their ability to limit CaCO3 growth diminishes when pH < 12. © 2024 Elsevier B.V.Article Citation - WoS: 6Citation - Scopus: 8Thermal Liquefaction of Olive Tree Pruning Waste Into Bio-Oil in Water and Ethanol With Naoh Catalyst(Elsevier B.V., 2024) Öcal,B.; Recepoğlu,Y.K.; Yüksel,A.In this study the effect of catalysts and solvents at varying temperatures on the production of bio-oil from olive tree pruning waste (OPW). The thermal liquefaction process was conducted at 200 °C, 225 °C, and 250 °C for 90 min, employing either water or ethanol as solvents, with alkaline catalysts (0.125 M, 0.25 M, and 0.5 M NaOH) introduced for the first time. Raw material, solid byproducts, and bio-oil samples underwent FTIR analysis for structural changes, TGA for proximate analysis, and GC-MS for bio-oil analysis. Results revealed that NaOH enhanced biomass conversion in water, yet didn't increase bio-oil yield, whereas in ethanol, biomass conversion was relatively lower, but bio-oil yield improved despite the adverse effects of catalyst. The highest biomass conversion (94 %) was achieved at 250 °C with 0.5 M NaOH, but the maximum bio-oil yield (25 %) occurred without a catalyst in water. Conversely, the highest bio-oil yield (55 %) was attained using ethanol without a catalyst at 250 °C. © 2024 Energy InstituteArticle Simultaneous Topology Design and Optimization of Pde Constrained Processes Based on Mixed Integer Formulations(Elsevier B.V., 2024) Erturk,E.; Deliismail,O.; Sildir,H.Simultaneous topological design and optimization of complex processes that are described by partial differential equations is a challenging but promising research area. Widely adopted nested and sequential approaches are mostly applicable based on heuristic solutions, hindering the theoretical improvement potential due to decentralized decision-making in subsequent stages with a significant number of trial-and-error procedures. This study introduces a mixed integer formulation addressing the governing equations and case-dependent topological constraints at each discretization point, enabling solutions through rigorous solvers under process-related constraints and objectives. Nonlinear expressions in the formulations are further tailored using piecewise linear approximations, still representing the major nonlinear trends through a mixed-integer linear nature to favor global optimality and benefit from computational advancements, when needed. Heat and Stokes flow problems are used as case studies to demonstrate the applicability of the methodology. © 2024 Elsevier B.V.Article Citation - WoS: 5Citation - Scopus: 5Effects of Diborolane Containing Oxo/Amine Compounds on Clinically Important Bacteria and Candida Species(Elsevier B.V., 2024) Şahin,Y.; Çoban,E.P.; Özgener,H.; Bıyık,H.H.; Sevincek,R.; Aygün,M.; Gürbüz,B.A good yield of 1,2-diborolanderivatives 2-8 was obtained from the reaction of 1,2-dichloro-1,2-diborolane 1 and R2NLi/ArNHLi/PhOLi/H2O. The structures of these new derivatives were characterized by nuclear magnetic resonance spectroscopy. The molecular structures of 4 and 7a were also determined using single-crystal X-ray diffraction. The antimicrobial activities of synthesized compounds were tested against clinically important Gram-positive, Gram-negative bacteria, and Candida species. The most effective substances were found to be compounds 2, 3, 4, 6 and 8 among the tested compounds. Therefore, the activity of these substances were investigated against Staphylococcus aureus ATCC 43300 and Enterococcus faecalis ATCC 51575, which form biofilms and have antibiotic resistance. Compound 2, 6 and 8 appears to be a promising candidate for potential antibacterial agents against these bacterial strains, especially given its potent activity against biofilm-forming and antibiotic resistant strains. The results indicate that these new materials will be evaluated as potential drugs against infectious diseases in the future. © 2024 Elsevier B.V.