Akademik Çıktılar

Permanent URI for this communityhttps://premium.gcris.co/handle/123456789/2

Browse

Now showing 1 - 16 of 16

Citation - WoS: 17
Aggregatibacter actinomycetemcomitans: GroEL protein promotes conversion of human CD4+T cells into IFNγ IL10 producing Tbet+Th1 cells
(Public Library Science, 2012) Saygili, Tahsin; Akincilar, Semih Can; Akgul, Bunyamin; Nalbant, Ayten; Akgül, Bünyamin
One of the heat shock family protein (Hsp) expressing bacteria is the gram negative, periodontal pathogen Aggregatibacter actinomycetemcomitans (Aa). A. actinomycetemcomitans' Hsp is a 64-kDa GroEL-protein, which has been shown to influence the host cells. In this study we used recombinant A. actinomycetemcomitans GroEL (rAaGroEL) protein as a model antigen to study GroEL-mediated T cell immune response. Human peripheral mononuclear cells (PBMCs), when stimulated with recombinant rAaGroEL, expressed early activation marker CD69 and IL-2R (CD25). CD25 and CD69 expressions were higher in CD4+ T cells compared to CD8+ T cells. rAaGroEL-responding CD4+ T cells expressed IL-10, IFN gamma and TNF alpha cytokines. Interestingly, there were also IL-10 and IFN gamma double cytokine producing CD4+ T cells. Additionally, IFN gamma expressing CD4+ T cells were also T-bet positive. Altogether the results suggest that rAaGroEL protein affects CD4+ T cells to differentiate into IFN gamma IL10-secreting T-bet+ Th1 cells.
Citation - WoS: 4
Citation - Scopus: 4
Convergence analysis and numerical solution of the benjamin-bona-mahony equation by lie-trotter splitting
(Tubitak Scientific & Technological Research Council Turkey, 2018) Zurnaci, Fatma; Gucuyenen Kaymak, Nurcan; Seydaoglu, Muaz; Tanoglu, Gamze
In this paper, an operator splitting method is used to analyze nonlinear Benjamin-Bona-Mahony-type equations. We split the equation into an unbounded linear part and a bounded nonlinear part and then Lie-Trotter splitting is applied to the equation. The local error bounds are obtained by using the approach based on the differential theory of operators in a Banach space and the quadrature error estimates via Lie commutator bounds. The global error estimate is obtained via Lady Windermere's fan argument. Finally, to confirm the expected convergence order, numerical examples are studied.
d3n3m3y3ni
(Can, 2025) d3n3m3
Dose Enhancement Effects of Different-Sized Nanoparticles on Tumors and Surrounding Tissues Using Geant4 Track Structure Simulation
(Sciendo, 2025) Tugrul, Taylan
Free radicals, which are the most important contributors to cell death in radiotherapy, appear to increase in the presence of nanoparticles. The nanoparticles can be localized within tumor tissues, providing enhanced protection to normal tissues during radiation therapy while achieving significant dose enhancement within tumors. In our study, the dose effects of different sizes of spherical gold nanoparticles were analyzed in the tumor environment and surrounding tissues under photon radiation at various energies with the track structure code using the TOPAS interface. The nano-lattice method was used to create an environment similar to the diffusion-based distribution of nanoparticles in the medium. The Geant4-DNA code was utilized for simulations conducted in this study. Although the interaction cross-section is lower at MeV photon energy levels, the results still indicate an increase in dose due to the presence of nanoparticles (NPs) in the medium. As the size of gold nanoparticles increases, the spread in dose enhancements becomes more apparent. The lowest average dose enhancement factor (DEF) values at lateral points were observed for 28.4 nm NPs at MeV photon energy. In this study, the contribution of gold nanoparticles to dose enhancement was investigated using the Monte Carlo track structure algorithm. Additionally, the potential dose variations in the surrounding tissue resulting from the introduction of gold nanoparticles were analyzed. Even though an increase in DEF values was observed at MeV energy levels, these values might vary with a better understanding of biological effects such as cell cycle disruption, oxidative stress, and impaired DNA repair. This study offers valuable insights into nanoparticle-assisted radiation applications, including optimal nanoparticle size and applicable energy levels. By enhancing our understanding of the effects on tissues beyond the tumor and within the surrounding environment, it aims to provide critical information for researchers in the field and make a meaningful contribution to the literature.
Dose Enhancement Effects of Different-Sized Nanoparticles on Tumors and Surrounding Tissues Using Geant4 Track Structure Simulation
(Sciendo, 2025) Tugrul, Taylan
Free radicals, which are the most important contributors to cell death in radiotherapy, appear to increase in the presence of nanoparticles. The nanoparticles can be localized within tumor tissues, providing enhanced protection to normal tissues during radiation therapy while achieving significant dose enhancement within tumors. In our study, the dose effects of different sizes of spherical gold nanoparticles were analyzed in the tumor environment and surrounding tissues under photon radiation at various energies with the track structure code using the TOPAS interface. The nano-lattice method was used to create an environment similar to the diffusion-based distribution of nanoparticles in the medium. The Geant4-DNA code was utilized for simulations conducted in this study. Although the interaction cross-section is lower at MeV photon energy levels, the results still indicate an increase in dose due to the presence of nanoparticles (NPs) in the medium. As the size of gold nanoparticles increases, the spread in dose enhancements becomes more apparent. The lowest average dose enhancement factor (DEF) values at lateral points were observed for 28.4 nm NPs at MeV photon energy. In this study, the contribution of gold nanoparticles to dose enhancement was investigated using the Monte Carlo track structure algorithm. Additionally, the potential dose variations in the surrounding tissue resulting from the introduction of gold nanoparticles were analyzed. Even though an increase in DEF values was observed at MeV energy levels, these values might vary with a better understanding of biological effects such as cell cycle disruption, oxidative stress, and impaired DNA repair. This study offers valuable insights into nanoparticle-assisted radiation applications, including optimal nanoparticle size and applicable energy levels. By enhancing our understanding of the effects on tissues beyond the tumor and within the surrounding environment, it aims to provide critical information for researchers in the field and make a meaningful contribution to the literature.
Citation - WoS: 4
Citation - Scopus: 9
End-to-end security implementation for mobile devices using TLS protocol
(Springer France, 2006) Kayayurt, Baris; Tuglular, Tugkan; Tuğlular, Tuğkan; Bilgisayar Mühendisliği Bölümü
End-to-end security has been an emerging need for mobile devices with the widespread use of personal digital assistants and mobile phones. Transport Layer Security Protocol (TLS) is an end-to-end security protocol that is commonly used on the Internet, together with its predecessor, SSL protocol. By implementing TLS protocol in the mobile world, the advantage of the proven security model of this protocol can be utilized. The main design goals of mobile end-to-end security protocol are maintainability and extensibility. Cryptographic operations are performed with a free library, Bouncy Castle Cryptography Package. The object oriented architecture of proposed end-to-end security protocol implementation makes the replacement of this library with another cryptography package easier. The implementation has been experimented with different cases, which represent use of different cryptographic algorithms.
Citation - WoS: 73
Evidence for water-tuned structural differences in proteins: an approach emphasizing variations inlocal hydrophilicity
(Public Library Science, 2012) Akdogan, Yasar; Reichenwallner, Joerg; Hinderberger, Dariush
We present experimental evidence for the significant effect that water can have on the functional structure of proteins in solution. Human (HSA) and Bovine Serum Albumin (BSA) have an amino acid sequence identity of 75.52% and are chosen as model proteins. We employ EPR-based nanoscale distance measurements using double electron-electron resonance (DEER) spectroscopy and both albumins loaded with long chain fatty acids (FAs) in solution to globally (yet indirectly) characterize the tertiary protein structures from the bound ligands' points of view. The complete primary structures and crystal structures of HSA and as of recently also BSA are available. We complement the picture as we have recently determined the DEER-derived solution structure of HSA and here present the corresponding BSA solution structure. The characteristic asymmetric FA distribution in the crystal structure of HSA can surprisingly be observed by DEER in BSA in solution. This indicates that the BSA conformational ensemble in solution seems to be narrow and close to the crystal structure of HSA. In contrast, for HSA in solution a much more symmetric FA distribution was found. Thus, conformational adaptability and flexibility dominate in the HSA solution structure while BSA seems to lack these properties. We further show that differences in amino acid hydropathies of specific structural regions in both proteins can be used to correlate the observed difference in the global (tertiary) solution structures with the differences on the primary structure level.
Citation - WoS: 23
Exact solutions of forced burgers equations with time variable coefficients
(Elsevier, 2013) Buyukasik, Sirin A.; Pashaev, Oktay K.
In this paper, we consider a forced Burgers equation with time variable coefficients of the form U-t + (mu(t)/mu(t))U + UUx = (1/2 mu(t))U-xx - omega(2)(t)x, and obtain an explicit solution of the general initial value problem in terms of a corresponding second order linear ordinary differential equation. Special exact solutions such as generalized shock and multi-shock waves, triangular wave, N-wave and rational type solutions are found and discussed. Then, we introduce forced Burgers equations with constant damping and an exponentially decaying diffusion coefficient as exactly solvable models. Different type of exact solutions are obtained for the critical, over and under damping cases, and their behavior is illustrated explicitly. In particular, the existence of inelastic type of collisions is observed by constructing multi-shock wave solutions, and for the rational type solutions the motion of the pole singularities is described. (c) 2012 Elsevier B.V. All rights reserved.
Citation - WoS: 3
Exactly solvable madelung fluid and complex burgers equations: a quantum sturm-liouville connection
(Springer, 2012) Buyukasik, Sirin A.; Pashaev, Oktay K.
Quantum Sturm-Liouville problems introduced in our paper (BuyukaAYA +/- k et al. in J Math Phys 50:072102, 2009) provide a reach set of exactly solvable quantum damped parametric oscillator models. Based on these results, in the present paper we study a set of variable parametric nonlinear Madelung fluid models and corresponding complex Burgers equations, related to the classical orthogonal polynomials of Hermite, Laguerre and Jacobi types. We show that the nonlinear systems admit direct linearazation in the form of Schrodinger equation for a parametric harmonic oscillator, allowing us to solve exactly the initial value problems for these equations by the linear quantum Sturm-Liouville problem. For each type of equations, dynamics of the probability density and corresponding zeros, as well as the complex velocity field and related pole singularities are studied in details.
Citation - WoS: 4
The importance of protein profiling in the diagnosis and treatment of hematologic malignancies
(Galenos Yayincilik, 2011) Sanli-Mohamed, Gulsah; Turan, Taylan; Ekiz, Huseyin Atakan; Baran, Yusuf; Baran, Yusuf
Proteins are important targets in cancer research because malignancy is associated with defects in cell protein machinery. Protein profiling is an emerging independent subspecialty of proteomics that is rapidly expanding and providing unprecedented insight into biological events. Quantitative assessment of protein levels in hematologic malignancies seeks a comprehensive understanding of leukemia-associated protein patterns for use in aiding diagnosis, follow-up treatment, and the prediction of clinical outcomes. Many recently developed high-throughput proteomic methods can be applied to protein profiling. Herein the importance of protein profiling, its exploitation in leukemia research, and its clinical usefulness in the treatment and diagnosis of various cancer types, and techniques for determining changes in protein profiling are reviewed. (Turk J Hematol 2011; 28: 1-14)
Kendi Kendini Temizleyen Kaşık
(Türk Patent Enstitüsü, 2025) Doğru, Denizhan; Şenoğlu, Aysel
Deneme Deneme Deneme
Citation - WoS: 16
Citation - Scopus: 18
Solitary wave solution of nonlinear multi-dimensional wave equation by bilinear transformation method
(Elsevier Science Bv, 2007) Tanoglu, Gamze
The Hirota method is applied to construct exact analytical solitary wave solutions of the system of multi-dimensional nonlinear wave equation for n-component vector with modified background. The nonlinear part is the third-order polynomial, determined by three distinct constant vectors. These solutions have not previously been obtained by any analytic technique. The bilinear representation is derived by extracting one of the vector roots (unstable in general). This allows to reduce the cubic nonlinearity to a quadratic one. The transition between other two stable roots gives us a vector shock solitary wave solution. In our approach, the velocity of solitary wave is fixed by truncating the Hirota perturbation expansion and it is found in terms of all three roots. Simulations of solutions for the one component and one-dimensional case are also illustrated. (C) 2006 Published by Elsevier B.V.
Citation - WoS: 9
Citation - Scopus: 8
Synthesis and characterization of novel high temperature structural adhesives based on nadic end capped MDA-BTDA-ODA copolyimide
(Iop Publishing Ltd, 2018) Acar, Oktay; Varis, Serhat; Isik, Tugba; Tirkes, Seha; Demir, Mustafa M.; Demir, Mustafa
A series of novel copolyimide structural adhesives were synthesized using 4,4'-diaminodiphenyl-methane (MDA), 3,4'-oxydianiline (ODA) and 3,3',4,4'-benzophenonetetracarboxylic acid dianhy-dride (BTDA) as co-monomers, and nadic anhydride as an end cap reagent. The adhesives with different MDA and ODA contents were examined in terms of their structure, thermal stability, mechanical properties, and adhesive performance. They have glass transition temperatures (T-g) about 400 degrees C, with thermal stability up to 500 degrees C. The effect of diamine monomer compositions on adhesion performance and processability of the copolyimides were studied. The copolyimides exhibited adhesion strength up to 16.3 MPa at room temperature. Nadic end capped MDA-BTDA-ODA copolyimide resins gained adjustable and controllable processability with the addition of ether bridged aromatic segments. The copolyimide adhesive with equimolar composition of MDA: ODA is distinguished form the both commercial PMR-15 and LARC RP-46 polyimides in terms of its better processability and mechanical performance.
Citation - WoS: 10
Transcriptomics analysis of circular RNAs differentially expressed in apoptotic HeLa cells
(Frontiers Media Sa, 2019) Yaylak, Bilge; Erdogan, Ipek; Akgul, Bunyamin; Akgül, Bünyamin
Apoptosis is a form of regulated cell death that plays a critical role in survival and developmental homeostasis. There are numerous reports on regulation of apoptosis by protein-coding genes as well as small non-coding RNAs, such as microRNAs. However, there is no comprehensive investigation of circular RNAs (circRNA) that are differentially expressed under apoptotic conditions. We have performed a transcriptomics study in which we first triggered apoptosis in HeLa cells through treatment with four different agents, namely cisplatin, doxorubicin, TNF-alpha and anti-Fas mAb. Total RNAs isolated from control as well as treated cells were treated with RNAse R to eliminate the linear RNAs. The remaining RNAs were then subjected to deep-sequencing to identify differentially expressed circRNAs. Interestingly, some of the dys-regulated circRNAs were found to originate from protein-coding genes well-documented to regulate apoptosis. A number of candidate circRNAs were validated with qPCR with or without RNAse R treatment as well. We then took advantage of bioinformatics tools to investigate the coding potential of differentially expressed RNAs. Additionally, we examined the candidate circRNAs for the putative miRNA-binding sites and their putative target mRNAs. Our analyses point to a potential for circRNA-mediated sponging of miRNAs known to regulate apoptosis. In conclusion, this is the first transcriptomics study that provides a complete circRNA profile of apoptotic cells that might shed light onto the potential role of circRNAs in apoptosis.
Citation - WoS: 13
Citation - Scopus: 18
Triboluminescent electrospun mats with blue-green emission under mechanical force
(American Chemical Society, 2017) Incel, Anil; Varlikli, Canan; McMillen, Colin D.; Demir, Mustafa M.; Demir, Mustafa
Fibrous mechanosensing elements can provide information about the direction of crack propagation and the mechanism of material failure when they are homogeneously dispersed into the bulk volume of materials. A fabrication strategy of fibrous systems showing triboluminescent (TL) responses is in high demand for such applications. In this work, micrometer-sized Cu(NCS) (py)(2)(PPh3) crystals were synthesized, and polymeric fibrous mats containing the TL crystals were obtained via electrospinning as a stress probe for the determination of mechanical impact. Four different polymeric systems have been employed (PMMA, PS, PU, and PVDF), and the mechano-optical sensing performance of electrospun mats of the polymer-crystal composites was measured. Photophysical properties (quantum yield, band gap, and broadness of the emission) of the TL crystal/electrospun mat composites were also studied. TL and PL emission maxima of the PU-based composite mat show identical behavior due to the chemical affinity between the two structures and the smallest fiber diameter. Moreover, the PU fiber mats exhibit long-lived bluish-green emission persisting over a large number of drops.
Citation - WoS: 10
Citation - Scopus: 11
An update on molecular biology and drug resistance mechanisms of multiple myeloma
(Elsevier Science inc, 2015) Mutlu, Pelin; Kiraz, Yagmur; Gunduz, Ufuk; Baran, Yusuf; Baran, Yusuf
Multiple myeloma (MM), a neoplasm of plasma cells, is the second most common hematological malignancy. Incidance rates increase after age 40. MM is most commonly seen in men and African-American population. There are several factors to this, such as obesity, environmental factors, family history, genetic factors and monoclonal gammopathies of undetermined significance (MGUS) that have been implicated as potentially etiologic. Development of MM involves a series of complex molecular events, including chromosomal abnormalities, oncogene activation and growth factor dysregulation. Chemotherapy is the most commonly used treatment strategy in MM. However, MM is a difficult disease to treat because of its marked resistance to chemotherapy. MM has been shown to be commonly multidrug resistance (MDR)-negative at diagnosis and associated with a high incidence of MDR expression at relapse. This review deals with the molecular aspects of MM, drug resistance mechanisms during treatment and also possible new applications for overcoming drug resistance. (C) 2015 Elsevier Ireland Ltd. All rights reserved.

Browse

Browsing Akademik Çıktılar by Access Right "info:eu-repo/semantics/openAccess"