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Article Citation - WoS: 12Citation - Scopus: 16Biomaterials and Tissue Engineering for Regenerative Repair of Articular Cartilage Defects(Turkish League Against Rheumatism, 2009) Tur, Kazim; Department of Metallurgical and Materials EngineeringArticular 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)Article Citation - WoS: 1Citation - Scopus: 3Evaluation of New Codes for Spectral-Amplitude Optical Code-Division Multiple-Access Communication Systems(Spie-int Society Optical Engineering, 2004) Murugesan, K; Ravichandran, VCNew classes of codes, namely extended modified prime sequence codes (EMPSC) and difference codes, both having an ideal in-phase cross-correlation (IPCC) value of one, are suggested for spectral-amplitude-coding optical code-division multiple-access communication systems. The general structure of the system is discussed with simpler encoder and decoder architectures based on fiber Bragg gratings. Since the influence of multiuser interference can be completely removed due to ideal IPCC, the performance analyses of the proposed codes have been carried out by incorporating the effects of phase-induced intensity noise (PIIN), shot noise, and thermal noise at the receiver, employing Gaussian approximation. Assuming typical system parameters, evaluation results show that with an increase in code weight, the maximum number of accommodative users in the system can be increased as well as significant improvements in bit error probability for a given number of active users. For the same code weight, the difference codes can support a greater number of simultaneous users than the other. It is found that the effects of PIIN dominate compared to shot noise and thermal noise at large powers, whereas the effects of PIIN and shot noise are highly reduced at low powers, so that thermal noise becomes a more influential limitation factor. In comparison with earlier codes, the error performance of EMPSC is similar to that of modified quadratic congruence codes, while difference codes resemble those codes developed based on Steiner systems. (C) 2004 Society of Photo-Optical Instrumentation Engineers.Article Citation - WoS: 42Citation - Scopus: 47A Novel Global Robust Stability Criterion for Neural Networks With Delay(Elsevier Science Bv, 2005) Singh, VA criterion based on the intervalised network parameters for the global robust stability of Hopfield-type neural networks with delay is presented. The criterion is compared with an earlier criterion. (c) 2005 Elsevier B.V. All rights reserved.Article Citation - WoS: 6Citation - Scopus: 6A Boundary Value Problem for Second Order Nonlinear Difference Equations on the Semi-Infinite Interval(Taylor & Francis Ltd, 2002) Guseinov, GSIn this paper, we consider a boundary value problem (BVP) for nonlinear difference equations on the discrete semi-axis in which the left-hand side being a second order linear difference expression belongs to the so-called Weyl-Hamburger limit-circle case. The BVP is considered in the Hilbert space l(2) and is formed via boundary conditions at a starting point and at infinity. Existence and uniqueness results for solutions of the considered BVP are established.Article Distance Laboratory Applications ERRL: A Study on Radio Communication in Electronic Field(IEEE, 2008) Aydın, Cansu Çiğdem; Özyurt, E.; Aydın, Elif; Çağıltay, Nergiz; Özbek, Mehmet Efe; Alparslan, Ceren; Kara, AliIn the last decade, the effect of internet usage in education is gradually increased. When we look from academic perspective, the new technologies provided alternatives for students learning. As distance education becomes important everyday, the indispensable elements of teaching and education, laboratories must be reachable via remote connection. Consequently, the education that is going to be given to the students will be more flexible with respect to place and time constraints and students can reach laboratory facilities at any time and anywhere not only in lectures and practical hours. In this study, European Remote Radio Laboratory (ERRL) which is a distance remote Radio Frequency (RF) laboratory designed for electrical-electronics students, is described generally. The software architecture, infrastructure and experiment that can be done with a remote connection have been described.Article Citation - WoS: 1Citation - Scopus: 3Multivariable Nonlinear Model Reference Control of Cement Mills(Arnold, Hodder Headline Plc, 2003) Efe, MÖ; Department of Electrical & Electronics EngineeringThis paper presents a method for model reference control of a cement milling circuit that has previously been studied several times. The approach presented is based on an experimentally justified model of a cement milling circuit. We derive the form of the control vector with the goal of driving the response of the system to that of a desired model in a noisy operating environment. The paper demonstrates the selection of the reference dynamics and the derivation of the control laws. The approach is based on the Lyapunov theory, and the results observed justify the tracking and stability claims of the paper.Article Citation - WoS: 76Citation - Scopus: 80Unique Ligand-Based Oxidative Dna Cleavage by Zinc(ii) Complexes of Hpyramol and Hpyrimol(Wiley-v C H verlag Gmbh, 2007) Maheswari, Palanisamy Uma; Barends, Sharief; Oezalp-Yaman, Seniz; de Hoog, Paul; Casellas, Helene; Teat, Simon J.; Reedijk, JanThe zinc(II) complexes reported here have been synthesised from the ligand 4-methyl-2-N-(2-pyridylmethyl)aminophenol (Hpyramol) with chloride or acetate counterions. All the five complexes have been structurally characterised, and the crystal structures reveal that the ligand Hpyramol gradually undergoes an oxidative dehydrogenation to form the ligand 4-methyl-2-N-(2-pyridylmethylene)aminophenol (Hpyrimol), upon coordination to Zn-II. All the five complexes cleave the phi X174 phage DNA oxidatively and the complexes with fully dehydrogenated pyrimol ligands were found to be more efficient than the complexes with non-dehydrogenated Hpyramol ligands. The DNA cleavage is suggested to be ligand-based, whereas the pure ligands alone do not cleave DNA. The DNA cleavage is strongly suggested to be oxidative, possibly due to the involvement of a non-diffusible phenoxyl radical mechanism. ne enzymatic religation experiments and DNA cleavage in the presence of different radical scavengers further support the oxidative DNA cleavage by the zinc(II) complexes.Article Citation - WoS: 26Citation - Scopus: 31New Lmi Condition for the Nonexistence of Overflow Oscillations in 2-D State-Space Digital Filters Using Saturation Arithmetic(Academic Press inc Elsevier Science, 2007) Singh, VimalA new criterion for the nonexistence of overflow oscillations in 2-D state-space digital filters described by Roesser model using saturation arithmetic is presented. The criterion is in the form of a linear matrix inequality (LMI) and hence computationally tractable. The criterion is compared with an earlier LMI-based criterion due to Xiao and Hill. It turns out that the present criterion may uncover some new A (i.e., other than those arrived at via Xiao-Hill's criterion) for which the absence of overflow oscillations is assured. (c) 2006 Elsevier Inc. All rights reserved.Article Citation - WoS: 4Citation - Scopus: 4Multi Input Dynamical Modeling of Heat Flow With Uncertain Diffusivity Parameter(Taylor & Francis inc, 2003) Efe, MÖ; Özbay, HThis paper focuses on the multi-input dynamical modeling of one-dimensional heat conduction process with uncertainty on thermal diffusivity parameter. Singular value decomposition is used to extract the most significant modes. The results of the spatiotemporal decomposition have been used in cooperation with Galerkin projection to obtain the set of ordinary differential equations, the solution of which synthesizes the temporal variables. The spatial properties have been generalized through a series of test cases and a low order model has been obtained. Since the value of the thermal diffusivity parameter is not known perfectly, the obtained model contains uncertainty. The paper describes how the uncertainty is modeled and how the boundary conditions are separated from the remaining terms of the dynamical equations. The results have been compared with those obtained through analytic solution.Article Citation - WoS: 24Citation - Scopus: 42Using Learning Styles Theory in Engineering Education(Taylor & Francis Ltd, 2008) Cagiltay, Nergiz ErcilStudies have shown that, while learning different concepts, people sometimes take different approaches (learning styles). Accordingly, their performance reflected differently in their academic studies. With the effect of globalisation to the educational environments, the influence of individual learning styles on educational performance is getting more significant. In this study, a learning style assessment tool was used to examine the relationship between students' learning styles and their performance in engineering education programmes. At the beginning of the programme, 285 students' learning styles were measured using a learning style assessment tool. Four years after the engineering education, their performance in the programme was compared with their individual learning styles. This study shows that most of the students are assimilators. Divergers and convergers follow the assimilators. The number of accommodators is very limited. The relationship between engineering students' learning styles and their performance is found: assimilators and convergers performed better than the divergers and accommodators. The performance difference between assimilators and divergers is statistically significant. The results of this study show that the learning style theory is a potential tool for guiding the design and improvement of courses and helping students to improve their individual performance.
