TR-Dizin

Permanent URI for this collectionhttps://ada.atilim.edu.tr/handle/123456789/21

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Citation - WoS: 11
Citation - Scopus: 15
Biomaterials and Tissue Engineering for Regenerative Repair of Articular Cartilage Defects
(Turkish League Against Rheumatism, 2009) Tur, Kazim; Department of Metallurgical and Materials Engineering; Department of Metallurgical and Materials Engineering
Articular cartilage defects heal very poorly and lead to degenerative arthritis. Existing medications cannot promote healing process; cartilage defects eventually require surgical replacements with autografts. As there is not enough source of articular cartilage that can be donated for autografting, materials that promote cartilage regeneration are important in both research and clinical applications. Tissue engineering involves cell growth on biomaterial scaffolds in vitro. These cells are then injected into cartilage defects for biological in vivo regeneration of the cartilage tissue. This review aims first to provide a brief introduction to the types of materials in medicine (biomaterials), to their roles in treatment of diseases, and to design factors and general requirements of biomaterials. Then, it attempts to sum up the recent advances in engineering articular cartilage; one of the most challenging area of study in biomaterials based tissue engineering, as an example to the research on regenerative solutions to musculoskeletal problems with an emphasis on the biomaterials that have been developed as scaffolds for cartilage tissue engineering. The definitive goal on cartilage regeneration is to develop a system using biomimetic approach to produce cartilage tissue that mimics native tissue properties, provides rapid restoration of tissue function, and is clinically translatable. This is obviously an ambitious goal; however, significant progress have been made in recent years; and further advances in materials design and technology will pave the way for creating significantly custom-made cellular environment for cartilage regeneration. (Turk J Rheumatol 2009; 24: 206-17)
Citation - WoS: 16
Citation - Scopus: 20
Common Fixed Point Theorems in Cone Banach Spaces
(Hacettepe Univ, Fac Sci, 2011) Abdeljawad, Thabet; Karapinar, Erdal; Tas, Kenan; Mathematics; Mathematics
Recently, E. Karapinar (Fixed Point Theorems in Cone Banach Spaces, Fixed Point Theory Applications, Article ID 609281, 9 pages, 2009) presented some fixed point theorems for self-mappings satisfying certain contraction principles on a cone Banach space. Here we will give some generalizations of this theorem.
Citation - WoS: 4
Citation - Scopus: 5
Construction of a Complex Jacobi Matrix From Two-Spectra
(Hacettepe Univ, Fac Sci, 2011) Guseinov, Gusein Sh; Mathematics; Mathematics
In this paper we study the inverse spectral problem for two-spectra of finite order complex Jacobi matrices (tri-diagonal matrices). The problem is to reconstruct the matrix using two sets of eigenvalues, one for the original Jacobi matrix and one for the matrix obtained by deleting the first column and the first row of the Jacobi matrix. An explicit procedure of reconstruction of the matrix from the two-spectra is given.
Citation - WoS: 3
Continuity and Change in Turkish Foreign Policy Toward Africa
(Hale Sivgin, 2008) Uchehara, Kieran E.
This article aims to give an overview of Turkey's improving relations with African countries. It indicates that Turkey's international relations concentrate more on her relations with the European Union, Caucasians, Balkans, the Middle East and USA. Turkey's opening up to Africa today, is a new development in her international relations. However, such relations had existed during the times of the Ottoman empire, especially with north Africa. Turkish academics, universities and media have not yet grasped the importance of Africa in the academic sense and as such none of them has a center on African research. Likewise, the African academics, universities and media. Other than communications between Turkey and African countries and related institutions on the subject matter, it is not possible to talk about significant serious data on Turkey-Africa relations. The relations between Turkey and Africa were on each individual African country's basis. However, with the recent development in the world today known as "globalization", Turkey is trying to improve her political and economic relations with the entire African continent and with the recent development, we have seen that there are high level visits between Turkey and African conutries. Trade relations between Turkey and African countries are in progress.
Creative Pattern Trials for Above the Keyboard Wear With Trompe L'oeil Illusion
(Anadolu Univ, 2022) Aydeniz, Sena Surmeli; Cegindir, Nese Yasar; Textile and Fashion Design
The design scenario of this study is based on seeking answers to the question "How can we produce different, extraordinary and original shirts for working women with the Trompe l'oeil (illusion) technique?". The sample of the study, in which the user-oriented design research method was used, is women working above the keyboard. Within the scope of the study, three women's shirts were produced with creative pattern applications. The classical techniques known in garment production have been reconstructed with the Trompe l'oeil technique. The findings were discussed in two dimensions as the process carried out for these three shirts and the prototype evaluation. Osborn's checklist was used to create the design value of the shirts. For the evaluations of the marketability of the products, measurement was made in the form of voting over Google Forms. As a result of the voting, the first prototype was found to be more suitable for the target audience. Based on the individual comments received, it has been observed that originality varies when the position and needs of the target audience come into play. The importance of the user profile in creative product design has been understood.
Citation - WoS: 6
Citation - Scopus: 6
Dynamic Reliability and Performance Evaluation of Multi-State Systems With Two Components
(Hacettepe Univ, Fac Sci, 2011) Eryilmaz, Serkan; Industrial Engineering; Industrial Engineering
In this paper we study multi-state systems consisting of two components when the number of system states and the number of states of each component are the same, i.e. the systems under consideration are homogeneous multi-state systems. In particular we evaluate multi-state series and cold standby systems assuming that the degradation in their components follow a Markov process. The behaviour of systems with respect to degradation rates is also investigated in terms of stochastic ordering.
Citation - Scopus: 9
The Effects of Eryngium Campestre Extracts on Glutathione-S Glutathione Peroxidase and Catalase Enzyme Activities;
(Turkish Pharmacists Association, 2014) Güneş,M.G.; İşgör,B.S.; İşgör,Y.G.; Shomali Moghaddam,N.; Geven,F.; Yildirim,Ö.
Eryngium campestre L. (Apiaceae) are known in Turkish folk medicine as ‘Bogadikeni’ and wildly distributed in all parts of Turkey. Infusion of different parts of this species are well known as diuretic, appetizer and stimulant. In the present study, methanol extracts from flowers and leaves of E. campestre were evaluated for their potential medicinal value in terms of biological targets participate in antioxidant defense such as glutathione-S-transferase (GST), glutathione peroxidase (GPx) and catalase (CAT). Results obtained show that the methanol extract of flowers were found to have higher amount of phenolic and flavonoid contents than the leaves. The evaluation of extracts against biological target revealed that, the maximum GST enzymes inhibition activities was observed with methanol extract from flowers of E. campestre with IC50 value of 363 ng/mL. In this study, none of the extracts evaluated were shown any reasonable GPx and CAT inhibition. © 2014, Turkish Pharmacists Association. All rights reserved.
Effects of Topological Structure of Project Network on Computational Cost
(Golden Light Publ, 2024) Aminbakhsh, Saman; Department of Civil Engineering
Understanding how network complexity affects optimization algorithms is crucial for improving computational efficiency. This study investigates how variations in network complexity impact the performance of optimization algorithms. By examining networks with different serial/parallel indicator (I2) values, the research uncovers several key insights into how topology influences computational requirements. The experiments show that higher I2 values, which are closer to serial configurations, heighten the problem's complexity. This study reveals that networks with lower I2 values, which exhibit steeper time-cost curves with fewer solutions over their efficient frontiers, require significantly more CPU time, indicating that project complexity does not necessarily scale with the extend of the Pareto fronts. This contradicts the expectation that more Pareto front solutions would inherently demand greater computational resources. Lastly, the study highlights that while the number of time-cost realizations is often used to gauge project complexity, it may not be conclusive on its own and that one complexity measure can outperform another. Although it can be an effective indicator, it does not fully capture the computational challenges posed by different network topologies. This study further acknowledges the difficulty in establishing a clear link between project performance and complexity due to the multifaceted nature of the problem. The findings suggest that exploring similar problems in other contexts could provide valuable insights into understanding and managing computational complexity.
Citation - Scopus: 34
Elastoplastic Response of a Long Functionally Graded Tube Subjected To Internal Pressure
(2005) Eraslan,A.N.; Akis,T.; Civil Engineering
Plane strain analytical solutions to functionally graded elastic and elastic-plastic pressurized tube problems are obtained in the framework of small deformation theory. The modulus of elasticity of the tube material is assumed to vary radially according to a 2 parametric model in a general parabolic form. The analytical plastic model is based on Tresca's yield criterion, its associated flow rule and ideally plastic material behavior. Exact solutions of field equations for elastic and plastic deformations are obtained. It is shown that the elastoplastic response of the functionally graded pressurized tube is affected notably by the radial variation of modulus of elasticity. It is also shown mathematically that the nonhomogeneous solution presented here reduces to that of a homogeneous one by the appropriate choice of the material parameters. © TÜBİTAK.
Citation - WoS: 0
Citation - Scopus: 1
Electrochemical Copolymerization of Thiophene Containing Pseudo-Polyether Cages With Pyrrole
(Tubitak Scientific & Technological Research Council Turkey, 2006) Cihaner, Atilla; Onal, Ahmet M.; Chemical Engineering; Chemical Engineering
Conducting copolymers were synthesized via the electrochemical oxidation of pyrrole (Py) in the presence of the monomer 1,12-bis(2-thienyl)-2,5,8,11-tetraoxadodecane (1). The presence of monomer I in the electrolytic solution greatly changed the CV behavior of Py during its potensiodynamic polymerization. The electroactivity of poly(I-co-Py) increased with the increasing amount of I in the comonomer mixture. Copolymer films were prepared via constant potential electrolysis in an electrolytic solution containing 0.1 M tetrabutylammonium hexafluorophosphate (TBAPF(6)) dissolved in acetonitrile. The spectroelectrochemical properties of the films were investigated using UV-VIS spectroscopy.
Citation - Scopus: 2
Field Extensions Having the Unique Subfield Property, and G-Cogalois Extensions
(2002) Albu,T.
We present a short proof, based on Cogalois Theory, of a result due to Acosta de Orozco and Vélez (1982, J. Number Theory 15, 388-405) characterizing separable simple radical field extensions with the unique subfield property, and prove that these extensions are precisely the simple G-Cogalois extensions with a cyclic Kneser group. © TÜBİTAK.
Citation - WoS: 0
Citation - Scopus: 0
Introduction: Marxifying IR, IRifying Marxism
(International Relations Council of Turkey, 2024) Yalvaç,F.; Joseph,J.; International Relations
Although the neglect of Marxism has been a pervasive characteristic of IR theory, there has been a marked revival of interest in Marxism. Marx’s materialist insights into the general historical development of societies, as well as his critique of capitalism and political economy, have served as alternative starting points for different critical approaches to IR and offers a welcome alternative to neorealism, constructivism, and poststructuralism that have dominated IR for several decades. Marxism provides a redefinition of IR by focusing on changes in material circumstances, historical conditions, and society instead of assuming unchanging and fixed structures of anarchy or the state. Marx’s analysis and insights into the dynamics of international relations have become even more important given the ongoing crisis of neoliberal capitalism, the rise of authoritarianism, right-wing nationalist populisms, and the racial and gendered subordinations accompanying them pointing to the importance of Marxifying IR and IRifying Marxism. © 2024, International Relations Council of Turkey. All rights reserved.
Citation - WoS: 2
Citation - Scopus: 2
Low Carbon Architectural Design
(Gazi Univ, 2018) Balku, Saziye; Bal Kocyigit, Filiz; Architecture; Energy Systems Engineering; Architecture; Energy Systems Engineering
Tendency towards sustainable energy resources is increasing and leading engineers and architects make joint efforts. Renewable energy potential present in nature can be used more efficiently so that while energy consumption is reducing, rate of energy gain, on the other hand, increases by architectural design methods. A sailing club in Golbasi, Ankara is designed as a low carbon building for optimum usage of solar and wind energy. It can be concluded using an energy efficient architectural design for a building before its construction makes it possible to meet the electrical and heat energy requirements at minimum cost and environmental friendly.
Citation - WoS: 1
Citation - Scopus: 0
Measuring Dependence Between Electricity Consumption and Economic Indicators Via Copulas: Turkish Case
(Gazi Univ, 2018) Evkaya, O. Ozan; Yozgatligil, Ceylan; Selcuk-Kestel, A. Sevtap; Mathematics
This paper implements copulas to identify the dependence structure between electricity consumption and its cofounding indicators. To achieve this, Turkish electricity demand, its economic and sectoral indicators are taken into account. As a first step, bivariate copulas are used to identify the best fitting copula and the degree of the dependence. Thereafter, multivariate model is established using vine copulas using highly correlated variables. The empirical results confirm the added value of the proposed approach in determining numerous tail properties. We indicate that the copulas are useful to underline, especially, the tail properties of indicators in the market for decision makers.
Citation - Scopus: 1
On the Derivation of Explicit Formulae for Solutions of the Wave Equation in Hyperbolic Space
(Hacettepe University, 2013) Guseinov,G.S.; Mathematics
We offer a new approach to solving the initial value problem for the wave equation in hyperbolic space in arbitrary dimensions. Our approach is based on the spectral analysis of the Laplace-Beltrami operator in hyperbolic space and some structural formulae for rapidly decreasing functions of this operator. © 2013, Hacettepe University. All rights reserved.
Citation - WoS: 3
On the Yielding of Two-Layer Composite Spherical Pressure Vessels
(Gazi Univ, 2017) Akis, Tolga; Civil Engineering
The yielding of two-layer composite spherical pressure vessels under either internal or external pressure is investigated analytically in the framework of small deformations and von Mises yield criterion. It is shown for both pressure cases that depending on the material properties and sphere dimensions, different modes of plasticization may take place. Unlike the deformation behavior of a single layer spherical pressure vessel, yielding may commence at the inner layer or at the outer layer or simultaneously at both layers of the assembly.
Citation - Scopus: 1
Reconstruction of Complex Jacobi Matrices From Spectral Data
(Hacettepe University, 2009) Guseinov,G.S.; Mathematics
In this paper, we introduce spectral data for finite order complex Jacobi matrices and investigate the inverse problem of determining the matrixfrom its spectral data. Necessary and sufficient conditions for the solvability of the inverse problem are established. An explicit procedure of reconstruction of the matrix from the spectral data is given.
Citation - WoS: 0
The Roles of Media, Social Comparison and Self-Discrepancy on Overweight/Obese Patients' Decision To Undergo Intragastric Botulinum Toxin-A Injection
(Istanbul Univ, Fac Letters, dept Psychology, 2022) Esiyok, Elif; Saygılı, Dilek Demirtepe; Saygili, Dilek Demirtepe; Saygılı, Dilek Demirtepe; Department of Psychology; Public Relations and Advertising
Body image is the sum of individuals' perceptions of their own bodies. There are various factors that affect body image, one of which is sociocultural factors. Sociocultural factors, including family, peers and the media, are important factors affecting the body image of individuals. The effects of being overweight on one's body image perception has been one of the most frequently researched topics in recent years. Studies have also shown that comparing one's body with people in the media, and the dissatisfaction with one's body resulting from it, motivates people to resort to various methods of losing weight. Doctors recommend various procedures for health reasons. Moreover, overweight women choose some surgical procedures such as intragastric botox injection, due to their concerns about their body image. Intragastric Botulinum Toxin-A injection (stomach botox) is one of them. This study aims to explore how sociocultural factors affect the overweight/ class I obese female patients' decision to undergo an intragastric botox injection treatment from an interpretative phenomenological approach. The sample of the study consisted of 12 female patients who had an intragastric botox injection in the last six months. Semi-structured interviews were conducted with the patients. The interpretive phenomenological analysis revealed seven themes; self-definition through physical characteristics, motivations towards intragastric botox injection, attitudes towards the body, the perceived effects of being overweight, comparing one's own body, the role of the media in the decision-making process, and treatment plans for changing one's appearance in the future. It has been found that the body image perceptions of the patients play an important role in the processing-decision-making processes.. In addition, it has been observed that social media is a channel frequently used by patients for the purpose of obtaining information. The study is important in terms of trying to understand cognitive processes including self-evaluations and body image, their motivations behind intragastric BTA injection, and attitudes toward their bodies.
Citation - WoS: 0
Tests of Rationality in the Turkish Foreign Exchange Market
(Central Bank Republic Turkey, 2014) Topbas, Neslihan; International Trade and Logistics
The rationality of expectations has been tested in many foreign exchange markets using survey data. This study is aimed at gaining empirical insights about the expectations of market participants in the Turkish foreign exchange market. Using survey data provided by Central Bank of Turkey on the exchange rate of the Turkish lira against the US dollar, it is determined that the mean of expectations of market participants for one year and one month ahead were higher than the mean of actual depreciation. The analysis resulted in rejection of the popular test for forward exchange rate unbiasedness in predicting the future spot exchange rate. Another test of rationality has also been checked and the result has been rejection as well, which can be interpreted that the forward premium contains additional information for exchange rate forecasts.
Citation - WoS: 1
Zero Consumption Monotype Education Buildings
(Gazi Univ, 2018) Bal Kocyigit, Filiz; Architecture
Turkey has mainly seven geographic zones but four climatic zones. Major influence on energy usage and educational buildings which perform well in energy terms will reap significant environmental and economic benefits for years to come. The lack of electric, heating-cooling and lighting comfort in the structure reduce the quality of education. Many village schools cannot provide training in enough conditions. Municipalities are preparing "Type School Project" for government schools, without thinking different zones conditions, directions and heights. At this stage, there arises importance of the Architectural Design Process for typical energy efficient design which can easily adapt to the location. The material must not only be transmits about 70-90% of solar radiation, but also its insulation quality. Additionally architectural form of building must be affected to take all solar energy, wind and water. In this study, architectural design method has been used for energy gain from transparent insulated trombe wall. And have been calculated in accordance with their manners in the middle, south, noth, east and west regions of Anatolia which are located in different degree-days regions on the basis of TS 825.

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