WoS İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.14901/698

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Characterization of the Potential Cytotoxicity of Klebsiella pneumoniae Isolated from Colorectal Cancer Patients Against a Normal Human Fibroblast Model
(Amer Chemical Soc, 2025) Kaci, Fatma Necmiye; Daglioglu, Cenk; Gormez, Arzu
Colorectal cancer is one of the most common types of cancer worldwide, with a multifactorial digestive pathology. Evidence has suggested that gut microbial dysbiosis is connected to the development of colorectal cancer by generating cancer cell-conducive microenvironments. Nevertheless, the relationship between colorectal cancer pathogenesis and microorganisms has not been fully clarified to date. Here, we addressed this issue and determined the cancer-causing potential of the culture filtrate and proteins of Klebsiella pneumoniae on healthy cells. In this study, the culture filtrate and total proteins of K. pneumoniae isolated from patients with colorectal cancer were investigated to determine their cytotoxic effects against the normal human fibroblast PCS-201-012 cell model. As a result of the isolation procedure, three different K. pneumoniae strains (named Kp1, Kp2, and Kp3) were obtained from biopsy samples. Their 16S rRNA gene sequences were submitted to the GenBank database under the accession numbers MK156319, MK156320, and MK156321, respectively. The WST-8 and hemolysis tests were performed to examine the exacerbating effect of these strains on normal cells. The apoptosis-inducing ability of the isolated strains was characterized based on a combination of several techniques: determination of caspase-3 activity, JC-1 mitochondrial assay, and flow cytometry-based FITC-Annexin-V/PI double staining. Moreover, the expression profiles of four candidate genes (APC, SMAD, KRAS, TP53), which play important roles in the development of colorectal cancer, were analyzed by the qRT-PCR method. Cell biology experiments demonstrated that the culture filtrate and proteins of the related strains clearly cause cell death in normal human fibroblasts due to increased inflammatory response and necrosis. Furthermore, the culture filtrates and proteins led to a decrease in the expression of tumor suppressor genes TP53, SMAD, and APC and an increase in the expression of the KRAS oncogene, emphasizing the tumorigenicity of the strains in colorectal cancer. These results revealed that K. pneumoniae strains are capable of triggering cytotoxicity in normal human fibroblast cells.
Citation - WoS: 5
Citation - Scopus: 5
Determination of the Effect of Tin Coating on Self-Fitting Properties of Dental Implants Made of Niti Alloy
(Amer Chemical Soc, 2022) Korkmaz, Ismail Hakki; Saglam, Mirac
Design and material research continues to increase dental implants' success rates, which is a widely applied treatment type. The size and morphology of the implant-bone interface are essential for implant stability. Our study produced a dental implant with two artificial tooth roots from NiTi alloy to increase the implant-bone contact surface. The properties of NiTi alloy, such as transformation temperature and composition, were determined by material characterization tests. Using NiTi alloy's shape memory effect, these artificial roots at body temperature were programmed with appropriate heat treatments for the self-fitting feature. Dental-implant-like models are coated with TiN to prevent Ni ion release. The corrosion tests were performed in Ringer's solution to determine the effect of TiN coating on Ni ion release. The nickel ion emission values showed that the TiN coating inhibited the release. In addition, it was determined that the TiN coating increased the shape memory transformation time of the NiTi alloy. In in vitro tests of NiTi and TiN-coated NiTi implants, it was observed that they completed self-fitting by deforming the trabecular bone, but the placement in the cortical bone was not complete. During the use of a shape memory implant, it should complete its transformation without contacting the cortical bone and should not cause a stress concentration.
Citation - WoS: 2
Citation - Scopus: 3
Electronic Band Structure of Gallium Sulfide (GaS) with Thickness Reduction Unveiling Parabolic and Pudding Mold Band Dispersion
(Amer Chemical Soc, 2025) Elameen, Ashraf Abdelrahman Assadig; Dutta, Debasis; Duman, Songul; Rosmus, Marcin; D'Olimpio, Gianluca; Gurbulak, Bekir; Politano, Antonio
Metal monochalcogenides (MXs) have attracted significant interest due to their unique electronic properties, which can be tuned by varying the thickness. Gallium sulfide (GaS) stands out among MX compounds for its potential in photocatalysis, thanks to its bandgap within the visible range. However, the theoretical predictions of its band structure have not been experimentally validated until now. To bridge this gap, we performed angle-resolved photoemission spectroscopy (ARPES) measurements on bulk GaS to investigate its electronic band structure which revealed that the VBM is located at the Gamma point, and from the analysis of isoenergy contours just below the Fermi level, the contours are relatively circular and centered around the Gamma point indicating a high degree of isotropy and symmetry in the electronic states. Additionally, density functional theory (DFT) calculations revealed that the valence bands are composed of Ga 4s, Ga 4p, and S 3p orbitals, while the deeper bands are from S 3s orbitals. Furthermore, the theoretical calculations are extended to monolayer, two-layer, and three layer to observe the evolution in the band structure. Our results highlight a unique "Pudding Mold" valence band maximum (VBM) at the Gamma point, featuring multiple maxima dispersed throughout the Brillouin zone. When the GaS sample is thinned to monolayers, this band transforms into a "Pudding Mold" shape, characterized by significant corrugation at the Gamma point. This transformation predicts an increase density of states (DOS), which is highly advantageous for photocatalysis. The higher DOS enhances the absorption and utilization of visible light, which is essential in photocatalytic applications, and also provides more active sites for catalytic reactions.
Citation - WoS: 13
Citation - Scopus: 12
Numerical Investigation of the Fire Behavior of Storage Rack Systems Protected by Intumescent Coating
(Amer Chemical Soc, 2022) Cirpici, Burak Kaan; Orhan, Suleyman Nazif; Yazici, Casim; Ozkal, Fatih Mehmet
Using a finite element strategy, this study investigates the behavior of beam-to-column connections in storage rack systems exposed to high temperatures. The purpose of this research was to develop moment-rotation (M-theta) curves after painting various structural members with varied config-urations in order to evaluate the performance of intumescent-coated beams, uprights, and connectors, which are components of storage rack systems. Within the scope of this work, finite element analyses were carried out in two stages. First, thermal analyses were performed using the transient thermal analysis system of ANSYS Workbench software to estimate the ultimate temperatures of the beam, upright, and connector, which were painted with 1 mm thick paint and exposed to standard (ISO-834) fire. The results were then compared to the Eurocode 3 Part 1.2 with a satisfactory agreement. In the second stage of the analysis, a total of 9 possible alternative models were investigated in the static structural analysis system, reflecting the effect of applying fire protection to the different portions of the rack system. Since the most critical stress level is achieved around the connector tabs, it has been observed that protection of the connector in individual or binary conditions provides higher performance while protection of the beam causes divergent joint behavior. Additionally, comparison of fully protected and unprotected conditions presents an increment of more than 7% on the joint's ultimate moment capacity and initial stiffness, which is an explicit contribution of the intumescent coating to fire resistance.
Citation - WoS: 60
Citation - Scopus: 63
Photophysics of an Asymmetric Donor-Acceptor-Donor' TADF Molecule and Reinterpretation of Aggregation-Induced TADF Emission in These Materials
(Amer Chemical Soc, 2017) Aydemir, Murat; Xu, Shidang; Chen, Chengjian; Bryce, Martin R.; Chi, Zhenguo; Monkman, Andrew P.
We report an in-depth photophysical investigation of an asymmetric donor-acceptor-donor' (D-A-D') thermally activated delayed fluorescence (TADF) molecule (4- (9H-carbazol-9-yl)phenyl) (4- (10 H-phenothiazin-10-yl)-phenyl)sulfone and compare its photophysical properties to the parent symmetric D-A-D and D'-A-D' molecules. These D-A-D type small molecules all show strong TADF. The work reveals how the relative orientations of D-A (D'-A) moieties favor reverse intersystem crossing (rISC) by forming stable charge transfer (CT) states. The key requirement for the efficient TADF emitters is to achieve a very small CT-local triplet state energy splitting, which is shown to be complex in the asymmetric molecule. Throughout the investigations, we show that in the asymmetric D-A-D' system, even though E-CT (D-A) > E-CT (D'-A), no evidence of energy transfer from D-A to A-D' is observed, nor from excited D to D'. This is ascribed to the near orthogonality of the D and D' units and the very strong decoupling of the electrons on the D and A in the CT state. In addition, the possibility of aggregation-induced TADF (AI-TADF) is examined and shown to be a manifestation of solvatochromism in these particular molecules.
Citation - WoS: 7
Citation - Scopus: 6
Regenerable Poly(dopamine)-Mediated Gold Nanostructure-Decorated Core-Shell Nanostructures of Magnetite/Polydopamine for Catalytic Dye Removal
(Amer Chemical Soc, 2024) Serginay, Nuray; Bingol, Mehmet Semih; Karatas, Erkan; Yilmaz, Mehmet
In this paper, we present a facile yet effective method for the fabrication of core-shell nanoparticles (NPs) of magnetite (Fe3O4) and polydopamine (Fe3O4@PDA) and their decoration with a tunable amount of gold NPs (AuNPs). For this, Fe3O4 NPs were fabricated through the polyol method and AuNPs were deposited onto Fe3O4@PDA via anchoring of as-prepared citrate-stabilized AuNPs or reduction of Au ions. PDA with its numerous catechol groups enabled the decoration of AuNPs in a well-controlled manner. The resultant Fe3O4@PDA@Au nanosystem exhibited highly efficient catalytic activity in removing crystal violet (CV) and malachite green (MG) as dye molecules. It was noticed that the quantity of deposited AuNPs was the primary determinant of the resulting catalytic activity of the suggested system. Both techniques resulted in NP systems demonstrating distinct catalytic activity with reaction constant values of 0.83 and 1.54 min-1 for removing CV and MG dyes, respectively. The complete dye removals were attained only within 4 min. Furthermore, the core-shell nanosystem was easily regenerated by removing it from the medium via an external magnet and subsequent washing. Even after five cycles, the catalytic system provided satisfying activity in both dyes indicating its high reusability capacity. The combination of AuNPs with distinct characteristics of PDA and magnetic NPs makes this core-shell nanosystem a viable platform for various catalytic and wastewater applications.
Citation - WoS: 5
Citation - Scopus: 5
Synthesis and Computational Evaluation of N-Acetyl Schiff Bases Incorporating 1,2,4-Triazoles for Dual Inhibition of Prostate Cancer Cells and Carbonic Anhydrases
(Amer Chemical Soc, 2025) Medetalibeyoglu, Hilal; Aytatli, Abdulmelik; Manap, Sevda; Atalay, Abdurrahman; Ortaakarsu, Ahmet Bugra; Tuzun, Burak; Yuksek, Haydar
In this study, we synthesized a series of novel N-acetyl Schiff bases (6a-e) containing 1,2,4-triazole moiety and evaluated their potential as anticancer agents through both experimental and computational approaches. Cytotoxicity assays on prostate cancer (PC) (DU145) and normal epithelial cells (PNT1a) demonstrated selective inhibition, particularly for compounds 6a, 6d, and 6e, with IC50 values of 73.25, 49.80, and 111.73 mu M, respectively, in DU145 cells. Notably, 6d exhibited a 10-fold selectivity toward cancer cells over normal cells. Enzyme inhibition studies demonstrated that compound 6d exhibited the most potent inhibitory activity against the carbonic anhydrase isoforms hCAI and hCAII, with the lowest recorded IC50 and K i values (7.12 and 9.26 mu M for hCAI, and 10.62 and 11.72 mu M for hCA II, respectively), suggesting strong potential for antiglaucoma therapeutic application. To elucidate molecular interactions, QM/MM molecular docking highlighted the strong affinity of compound 6d for the active sites of CYP17A1, hCAI, and hCAII enzymes. The coordination of functional groups with key residues, particularly the Zn2+ ion and HEM group, was confirmed by detailed binding analyses. Molecular dynamics simulations further validated the stability of these interactions over a 100 ns trajectory, with 6d maintaining robust engagement with the protein targets. This stability was reflected in consistent RMSD and RMSF profiles, with minimal fluctuations, particularly in CYP17A1 complexes, suggesting a stable binding conformation. The Markov State Model (MSM) analysis, integrated with TICA-FES and MM-GBSA calculations, revealed rapid conformational stabilization of 6d, especially in CYP17A1 complexes. The observed deeper energy wells in diffusion maps indicate stronger binding affinities and reduced conformational transitions compared to reference inhibitors, such as abiraterone and acetazolamide. These computational insights align with experimental findings, suggesting that 6d holds significant promise as a potent dual-target inhibitor with applications in prostate cancer therapy and glaucoma treatment.
Citation - WoS: 32
Citation - Scopus: 35
Synthesis of a Novel Cyclic Prodrug of S-Allyl Able to Attenuate LPS-Induced ROS Production Through the Inhibition of MAPK Pathways in U937 Cells
(Amer Chemical Soc, 2015) Patruno, Antonia; Fornasari, Erika; Di Stefano, Antonio; Cerasa, Laura S.; Marinelli, Lisa; Baldassarre, Leonardo; Cacciatore, Ivana
A novel cyclic prodrug of S-allyl-glutathione (CP11), obtained by using an acyloxy-alkoxy linker, was estimated for its pharmacokinetic and biological properties. The stability of CP11 was evaluated at pH 1.2, 7.4, in simulated fluids with different concentrations of enzymes, and in human plasma. The anti-inflammatory ability of CP11 was assessed in U937 cells, an immortalized human monocyte cell line. Results showed that CP11 is stable at acidic pH showing a possible advantage for oral delivery due to the longer permanence in the stomach. Having a permeability coefficient of 2.49 X 10(-6) cm s(-1), it was classified as discrete BBB-permeable compound. Biological studies revealed that CP11 is able to modulate inflammation mediated by LPS in U937 cells preventing the increase of ROS intracellular levels through interaction with the MAPK pathway.

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