Scopus İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12469/1248

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Tulczyjew's Triplet With an Ehresmann Connection I: Trivialization and Reduction
(World Scientific Publ Co Pte Ltd, 2023) Esen, Ogul; Kudeyt, Mahmut; Sutlu, Serkan
We study the trivialization and the reduction of Tulczyjew's triplet, in the presence of a symmetry and an Ehresmann connection associated to it. We thus establish a geometric pathway for the Legendre transformations on singular dynamical systems.
Electromagnetic Interactions of Heavy Ions at Small Impact Parameters and Lepton Pair Productions
(Institute of Physics Publishing, 2011) Güçlü, Mehmet Cem; Yılmaz Şengül, Melek
In peripheral collisions the strong electromagnetic fields are produced since the fully stripped heavy ions moves at ultra-relativistic velocities. Lepton pairs especially the electron-positron pairs are the result of this collisions. At the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) virtual photons produce many particles such as electron-positron pairs heavy lepton (muons and tauons) pairs magnetic monopoles W-pairs b-quark pairs and possibly the Higgs. At small impact parameters the colliding nuclei make peripheral collisions photon fluxes are very large and these are responsible for the multiple photonuclear interactions. Free pair productions bound free pair productions and nuclear Coulomb excitations are important examples of such interactions and these processes play important roles in the beam luminosity at RHIC and LHC. Here we obtained bound free electron-positron pair production with nuclear breakup for heavy ion collisions at RHIC and LHC.
Citation - Scopus: 57
Introduction: Orienting Istanbul-Cultural Capital of Europe?
(Routledge Journals Taylor & Francis Ltd, 2010) Göktürk, Deniz; Soysal, Levent; Türeli, Ipek
[Abstract Not Available]
Citation - WoS: 27
Citation - Scopus: 26
New Biological and Chemical Evidences of Two Lamiaceae Species (thymbra Capitata and Thymus Sipyleus Subsp. Rosulans): in Vitro, in Silico and Ex Vivo Approaches
(Mdpi, 2022) Llorent-Martinez, Eulogio J.; Ruiz-Medina, Antonio; Zengin, Gokhan; Ak, Gunes; Jugreet, Sharmeen; Mahomoodally, Mohamad Fawzi; Emre, Gizem
In this study, the methanolic and infusion extracts of two species, Thymbra capitata and Thymus sipyleus subsp. rosulans, were tested for their chemical composition and biological abilities (antioxidant, enzyme inhibitory and anti-inflammatory effects). The extracts yielded total phenolic and flavonoid contents in the range of 83.43-127.52 mg GAE/g and 9.41-46.34 mg RE/g, respectively. HPLC analysis revealed rosmarinic acid to be a major component of the studied extracts (15.85-26.43%). The best ABTS radical scavenging ability was observed in the methanol extract of T. capitata with 379.11 mg TE/g, followed by in the methanol extract of T. sipylus (360.93 mg TE/g). In the CUPRAC assay, the highest reducing ability was also found in the methanol extract of T. capitata with 802.22 mg TE/g. The phosphomolybdenum ability ranged from 2.39 to 3.61 mmol TE/g. In terms of tyrosinase inhibitory effects, the tested methanol extracts (83.18-89.66 mg KAE/g) were higher than the tested water extracts (18.74-19.11 mg KAE/g). Regarding the BChE inhibitory effects, the methanol extracts were active on the enzyme while the water extracts showed no inhibitory effect on it. Overall, the methanolic extracts showed better enzyme inhibition compared to the infusion extracts. Molecular docking also showed the selected exhibited potential binding affinities with all enzymes, with a preference for cholinesterases. Additionally, the extracts were effective in attenuating the LPS-induced increase in COX-2 and IL-6 gene expression in isolated colon, thus indicating promising anti-inflammatory effects. The preliminary results of this study suggest that these species are good natural sources of antioxidants and also provide some scope as enzyme inhibitors, most likely due to their bioactive contents such as phenolic acids, and thus can be exploited for different applications related to health promotion and disease prevention.
Citation - WoS: 1
Citation - Scopus: 1
Continuity and Change in Turkish Politics: Economic and Behavioural Explanations of Democratic Backsliding
(Routledge Journals, Taylor & Francis Ltd, 2024) Aydin, Mustafa; Yildirim, Kerem
This paper introduces a special issue focusing on the intricacies of Turkey's party system and the evolution of Turkish party competition amid democratic challenges. The introduction provides a brief overview of each paper in this special issue, which delves into the relationship between economic factors and voter behavior, offering insights into the continued dominance of the ruling party. While doing so, the special issue specifically examines the 2023 Turkish General elections, presenting alternative perspectives on how the incumbent party maintains its electoral success.
Citation - WoS: 1
Citation - Scopus: 1
Across Dimensions: Two- and Three-Dimensional Phase Transitions From the Iterative Renormalization-Group Theory of Chains
(2020) Keçoğlu, İbrahim; Berker, A. Nihat
Sharp two- and three-dimensional phase transitional magnetization curves are obtained by an iterative renormalization-group coupling of Ising chains, which are solved exactly. The chains by themselves do not have a phase transition or nonzero magnetization, but the method reflects crossover from temperaturelike to fieldlike renormalization-group flows as the mechanism for the higher-dimensional phase transitions. The magnetization of each chain acts, via the interaction constant, as a magnetic field on its neighboring chains, thus entering its renormalization-group calculation. The method is highly flexible for wide application.
Citation - WoS: 17
Citation - Scopus: 17
The Stage: a Space for Queer Subjectification in Contemporary Turkey
(Routledge Journals Taylor & Francis Ltd, 2012) Selen, Eser
This article focuses on the role of the stage in complex modes of gender performativity in the work of three Turkish performers: Zeki Muren (1931-1996) Bulent Ersoy (b. 1952) and Seyfi Dursunoglu (b. 1932) a.k.a. Huysuz Virjin [Cranky Virgin]. These three I suggest are the pioneers of contemporary Turkish queer performance. Their performances - both on-and off-stage - are validated through a reiterative absence of queerness in their everyday lives and stand in the midst of various negotiations between queers and the secular Islamic nation-state in Turkey. In the works of Muren Ersoy and Huysuz the stage is suggestive of a space where queerness can be managed. It is a contested space that does at least allow for the communication of queer ideas to a wider audience. I discuss the works of these three performers as three variations of queerness in Turkey in relation to different eras and different political climates that are directly related to the nation-state's desire to perform modernity. While explicating complicated modes of gender performativity I consider the stage as the primary space for a queer body to exist. Through this discussion I aim to activate debates both within and against the context of secular Islam on gendered political space and on those overlooked sexualized spaces in which the nation-state produces powerful yet unstable values to manage queer subjectivity in contemporary Turkey.
Citation - WoS: 9
Citation - Scopus: 9
Smoke-Free Turkey: Evaluation of Outdoor Areas of Public Places
(Academic Press Inc Elsevier Science, 2019) Kaplan, Bekir; Grau-Perez, Maria; Çarkoğlu, Aslı; Ergör, Gül; Hayran, Mutlu; Navas-Acien, Ana; Cohen, Joanna E.
Significance: Secondhand tobacco smoke (SHS) exposure is a major cause of morbidity and mortality around the world. The objective of this study was to evaluate the presence of smoking in outdoor areas of public places in three largest Turkish cities (Istanbul Ankara and Izmir). Method: For this cross-sectional observational study the Turkish Statistical Institute randomly selected 10 sampling points in each city. Around each sampling point fieldworkers visited the closest bars/nightclubs cafes government buildings hospitals restaurants schools shopping malls traditional coffee houses universities children's playgrounds parks and open markets. We observed smoking ashtrays and cigarette butts at the outdoor areas of public venues within the urban districts of each city. The fieldwork was conducted in April–May 2016. Results: 477 venues were observed covering 1017 outdoor locations in which 17737 people were observed. Smoking in outdoor areas ranged from 3.7% around schools to 90% in open markets. Ashtrays were almost ubiquitous in hospitals (95.6%) shopping malls (92.0%) and universities (90.9%). Cigarette butts were more often observed in open markets (100%) shopping malls (96%) universities (95.5%) and parks (93.3%). Smoking at outdoor areas around schools was significantly lower than around other venues. Conclusion: Smoking in outdoor areas was common in most public places in Turkey except schools. The current indoor SHS legislation should be extended to cover adjacent outdoor areas of public venues in order to effectively protect people from SHS exposure in Turkey. © 2019 The Authors
Citation - WoS: 5
Citation - Scopus: 5
Hand Dominance and Congruence for Wrist-Worn Haptics Using Custom Voice-Coil Actuation
(Ieee-inst Electrical Electronics Engineers inc, 2024) Adeyemi, Ayoade; Sen, Umit; Ercan, Samet Mert; Sarac, Mine
During virtual interactions, rendering haptic feedback on a remote location (like the wrist) instead of the fingertips frees users' hands from mechanical devices. This allows for real interactions while still providing information about the mechanical properties of virtual objects. In this letter, we investigate the impact of using the dominant or non-dominant hand for virtual interactions and the best mapping between the active hand and the wrist receiving the haptic feedback, which can be defined as hand-wrist congruence through a user experiment based on a stiffness discrimination task. To render force feedback, we present CoWrHap - a novel wrist-worn haptic device with custom-made voice coil actuation. Our results show that participants performed the tasks (i) better with non-congruent mapping but reported better experiences with congruent mapping, and (ii) with no statistical difference in terms of hand dominance but with better user experience (enjoyment, pleasantness, etc.) using their dominant hands.
Citation - Scopus: 15
Extrapolating Continuous Color Emotions Through Deep Learning
(American Physical Society, 2020) Ram,V.; Schaposnik,L.P.; Konstantinou,N.; Volkan,E.; Papadatou-Pastou,M.; Manav,B.; Mohr,C.
By means of an experimental dataset, we use deep learning to implement an RGB (red, green, and blue) extrapolation of emotions associated to color, and do a mathematical study of the results obtained through this neural network. In particular, we see that males (type-m individuals) typically associate a given emotion with darker colors, while females (type-f individuals) associate it with brighter colors. A similar trend was observed with older people and associations to lighter colors. Moreover, through our classification matrix, we identify which colors have weak associations to emotions and which colors are typically confused with other colors. © 2020 authors. Published by the American Physical Society.
Citation - WoS: 9
Citation - Scopus: 12
Controlling the Growth of Particle Size and Size Distribution of Silica Nanoparticles by the Thin Film Structure
(Springer, 2012) Uysal, Bengü Özuğur; Tepehan, Fatma Zehra
Nanostructured silicondioxide thin films were prepared by sol-gel spin coating technique. The SiO2 films were made using a conventional mixture of tetraethoxysilane (TEOS) deionized water and ethanol with various NH3/TEOS ratios. The nanostructured silica films were made using a mixture of the SiO2 sol and regular SiO2 sol to control the enlargement of the particles inside the films. The structural morphological and optical characterizations of the as-deposited and annealed films were carried out using X-ray diffraction (XRD) atomic force microscopy scanning electron microscopy NKD spectrophotometer and ultraviolet-visible (UV-vis) spectroscopy. The transmittance data of the infrared spectra of the films were recorded using an FT-IR Spectrometer. The XRD studies showed that as-deposited films were amorphous and the formation of the alfa-cristobalite phase of the silica film was investigated at annealing temperature close to 1100 A degrees C. Optical properties of the transmittance spectra in the s and p-polarization modes were collected. Refractive indices and extinction coefficients were determined with respect to the NH3/TEOS ratios in the compositions of the films. Optical cut-off wavelength values were investigated from the extrapolation of the absorbance spectra which was estimated from the UV-vis spectroscopy measurements. A red shift in the absorption threshold indicated that the size of silica nanoparticles was increased by an increase in the NH3/TEOS volume ratio from 1:64 to 1:8.
Establishment of reference intervals of laboratory tests using hospital patient data
(Marmara Üniversitesi Yayınevi, 2002) Toprakçı, Mustafa; Emerk, Kaya
Objective: In this study, hospital patient data was used to derive reference intervals for selected clinical laboratory tests. Methods: Data were obtained indirectly using our hospital database including both sexes. No selection criteria have been applied. The data has been partitioned into only three age groups as, 3-20, 21-60 and 61 to older in order to prevent age related grouping in the distribution. The distributions have been checked by normality analysis using Kolmogorov-Smirnov test. Nonparametric percentile estimate method was used to obtain reference intervals in the age groups of 21-60 and 61 to older. In age group 3- 20, the number of data were below 120 in most tests so, GraphROC for Windows, a statistical package which performs a robust modified nonparametric method, was used to find reference intervals. Results: Most of the test data did not show Gaussian distribution form and parametric analysis of these data has failed. Instead, nonparametric analysis has succeeded in establishing the intervals in three age groups. Conclusion: The results resembled the characteristics of our hospital patient population. Especially, protein and lipid parameters showed clear differences in our population, compared to the reference values of the manufacturer, which are currently used. This study has been a clear evidence indicating the importance of determination of reference intervals and the analysis of indirectly selected hospital patient data using nonparametric statistical techniques.
Citation - WoS: 12
Citation - Scopus: 16
Social Media Adoption: a Process-Based Approach
(Taylor & Francis Inc, 2016) Toker, Ayşegül; Seraj, Mina; Kuşçu, Asli; Yavuz, Ramazan; Koch, Stefan; Bisson, Christophe
This research conceptualizes and measures social media adoption (SMA) of companies with a process-based approach and explains its antecedents of micro- and macro-environment size and ownership as well as its consequence of intention to increase resources dedicated to social media. Based on data from 310 Turkish small and medium enterprises the study first develops a conceptual framework on the pillars of internal and external stakeholder focus as well as relationship and information oriented implementation. Based on these two dimensions it discusses the novel concepts of social customer relations social stakeholder communication social intelligence and social responsiveness related to SMA. The study further indicates that ownership type and micro environment play a role in SMA and that path dependence exists in the interplay of current adoption and future intentions.
Citation - Scopus: 1
Block Elimination Distance
(Springer Science and Business Media Deutschland GmbH, 2021) Diner, Ö.Y.; Giannopoulou, A.C.; Stamoulis, G.; Thilikos, D.M.
We introduce the parameter of block elimination distance as a measure of how close a graph is to some particular graph class. Formally, given a graph class G, the class B(G) contains all graphs whose blocks belong to G and the class A(G) contains all graphs where the removal of a vertex creates a graph in G. Given a hereditary graph class G, we recursively define G( k ) so that G(0 )= B(G) and, if k? 1, G( k )= B(A(G( k - 1 )) ). The block elimination distance of a graph G to a graph class G is the minimum k such that G? G( k ) and can be seen as an analog of the elimination distance parameter, defined in [J. Bulian & A. Dawar. Algorithmica, 75(2):363–382, 2016], with the difference that connectivity is now replaced by biconnectivity. We show that, for every non-trivial hereditary class G, the problem of deciding whether G? G( k ) is NP-complete. We focus on the case where G is minor-closed and we study the minor obstruction set of G( k ) i.e., the minor-minimal graphs not in G( k ). We prove that the size of the obstructions of G( k ) is upper bounded by some explicit function of k and the maximum size of a minor obstruction of G. This implies that the problem of deciding whether G? G( k ) is constructively fixed parameter tractable, when parameterized by k. Our results are based on a structural characterization of the obstructions of B(G), relatively to the obstructions of G. Finally, we give two graph operations that generate members of G( k ) from members of G( k - 1 ) and we prove that this set of operations is complete for the class O of outerplanar graphs. This yields the identification of all members O? G( k ), for every k? N and every non-trivial minor-closed graph class G. © 2021, Springer Nature Switzerland AG.
Citation - WoS: 8
Citation - Scopus: 9
An Inverse Coefficient Problem for a Quasilinear Parabolic Equation With Periodic Boundary and Integral Overdetermination Condition
(Wiley-Blackwell, 2015) Bağlan, İrem Sakınç; Kanca, Fatma
In this paper the inverse problem of finding the time-dependent coefficient of heat capacity together with the solution periodic boundary and integral overdetermination conditions is considered. Under some natural regularity and consistency conditions on the input data the existence uniqueness and continuous dependence upon the data of the solution are shown. Some considerations on the numerical solution for this inverse problem are presented with an example. Copyright (c) 2014 John Wiley & Sons Ltd.
Citation - WoS: 4
Citation - Scopus: 4
Composite Hydrogel of Polyacrylamide/Starch as a Novel Amoxicillin Delivery System
(Mdpi, 2024) Poyraz, Yagmur; Baltaci, Nisa; Hassan, Gana; Alayoubi, Oubadah; Uysal, Bengu Ozugur; Pekcan, Onder
This study investigates the development and characterization of a novel composite hydrogel composed of polyacrylamide (PAAm), starch, and gelatin for use as an amoxicillin delivery system. The optical properties, swelling behavior, and drug release profile of the composite hydrogel's were studied to evaluate its efficacy and potential applications. UV-visible spectroscopy was employed to determine the optical properties, revealing significant transparency in the visible range, which is essential for biomedical applications. The incorporation of starch and gelatin into the polyacrylamide matrix significantly enhanced the hydrogel's swelling capacity and biocompatibility. Studies on drug delivery demonstrated a sustained release profile of amoxicillin in simulated gastrointestinal fluids, which is essential for maintaining therapeutic levels for a prolonged amount of time. The results indicate that the composite hydrogel of PAAm/starch/gelatin has good swelling behavior, appealing optical characteristics, and a promising controlled drug release mechanism. These results point to this hydrogel's considerable potential as a drug delivery method, providing a viable path toward enhancing the medicinal effectiveness of amoxicillin and maybe other medications.
A Robust Localization Framework To Handle Noisy Measurements in Wireless Sensor Networks
(IEEE, 2009) Erten, Cesim; Karataş, Ömer
We construct a robust localization framework to handle noisy measurements in wireless sensor networks. Traditionally many approaches employ the distance information gathered from ranging devices of the sensor nodes to achieve localization. However the measurements of these devices may contain noise both as hardware noise and as environmental noise due to the employment conditions of the network. It Is necessary to provide a general framework that handles such a noise in data and yet still be applicable within several localization algorithms. In order to handle noise in distance measurements our framework utilizes convex constraints and confidence intervals of a random variable. At the end of the localization process nodes are assigned to a set of feasible regions with corresponding probabilities. The accuracy of the localization can be adjusted and the framework can easily be embedded to work within previously suggested localization algorithms.
Citation - Scopus: 1
Ideology, political agenda, and conflict: A comparison of american, european, and turkish legislatures' discourses on kurdish question
(Center for Foreign Policy and Peace Research, Ihsan Dogramaci Peace Foundation, 2017) Ünver,A.
Combining discourse analysis with quantitative methods, this article compares how the legislatures of Turkey, the US, and the EU discursively constructed Turkey's Kurdish question. An examination of the legislative-political discourse through 1990 to 1999 suggests that a country suffering from a domestic secessionist conflict perceives and verbalizes the problem differently than outside observers and external stakeholders do. Host countries of conflicts perceive their problems through a more security-oriented lens, and those who observe these conflicts at a distance focus more on the humanitarian aspects. As regards Turkey, this study tests politicians' perceptions of conflicts and the influence of these perceptions on their preexisting political agendas for the Kurdish question, and offers a new model for studying political discourse on intra-state conflicts. The article suggests that a political agenda emerges as the prevalent dynamic in conservative politicians' approaches to the Kurdish question, whereas ideology plays a greater role for liberal/pro-emancipation politicians. Data shows that politically conservative politicians have greater variance in their definitions, based on material factors such as financial, electoral, or alliance-building constraints, whereas liberal and/or left-wing politicians choose ideologically confined discursive frameworks such as human rights and democracy.
Citation - WoS: 55
Citation - Scopus: 83
Machine Type Communications: Key Drivers and Enablers Towards the 6g Era
(SPRINGER, 2021) Mahmood, Nurul Huda; Boecker, Stefan; Moerman, Ingrid; Lopez, Onel A.; Munari, Andrea; Mikhaylov, Konstantin; Clazzer, Federico; Bartz, Hannes; Park, Ok-Sun; Mercier, Eric; Saidi, Selma; Osorio, Diana Moya; Jantti, Riku; Pragada, Ravikumar; Annanpera, Elina; Ma, Yihua; Wietfeld, Christian; Andraud, Martin; Liva, Gianluigi; Chen, Yan; Garro, Eduardo; Burkhardt, Frank; Liu, Chen-Feng; Alves, Hirley; Sadi, Yalçın; Kelanti, Markus; Dore, Jean-Baptiste; Kim, Eunah; Shin, JaeSheung; Park, Gi-Yoon; Kim, Seok-Ki; Yoon, Chanho; Anwar, Khoirul; Seppanen, Pertti
The recently introduced 5G New Radio is the first wireless standard natively designed to support critical and massive machine type communications (MTC). However, it is already becoming evident that some of the more demanding requirements for MTC cannot be fully supported by 5G networks. Alongside, emerging use cases and applications towards 2030 will give rise to new and more stringent requirements on wireless connectivity in general and MTC in particular. Next generation wireless networks, namely 6G, should therefore be an agile and efficient convergent network designed to meet the diverse and challenging requirements anticipated by 2030. This paper explores the main drivers and requirements of MTC towards 6G, and discusses a wide variety of enabling technologies. More specifically, we first explore the emerging key performance indicators for MTC in 6G. Thereafter, we present a vision for an MTC-optimized holistic end-to-end network architecture. Finally, key enablers towards (1) ultra-low power MTC, (2) massively scalable global connectivity, (3) critical and dependable MTC, and (4) security and privacy preserving schemes for MTC are detailed. Our main objective is to present a set of research directions considering different aspects for an MTC-optimized 6G network in the 2030-era.
Citation - WoS: 8
Citation - Scopus: 8
Cryogenic X-Ray Crystallographic Studies of Biomacromolecules at Turkish Light Source Turkish Delight
(Tubitak Scientific & Technological Research Council Turkey, 2023) Atalay, Necati; Akcan, Enver Kamil; Gul, Mehmet; Ayan, Esra; Destan, Ebru; Ertem, Fatma Betuel; Tokay, Nurettin
X-ray crystallography is a robust and powerful structural biology technique that provides high-resolution atomic structures of biomacromolecules. Scientists use this technique to unravel mechanistic and structural details of biological macromolecules (e.g., proteins, nucleic acids, protein complexes, protein-nucleic acid complexes, or large biological compartments). Since its inception, single-crystal cryocrystallography has never been performed in Turkiye due to the lack of a single-crystal X-ray diffractometer. The X-ray diffraction facility recently established at the University of Health Sciences, Istanbul, Turkiye will enable Turkish and international researchers to easily perform high-resolution structural analysis of biomacromolecules from single crystals. Here, we describe the technical and practical outlook of a state-of-the-art home-source X-ray, using lysozyme as a model protein. The methods and practice described in this article can be applied to any biological sample for structural studies. Therefore, this article will be a valuable practical guide from sample preparation to data analysis.

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