Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 6Citation - Scopus: 6Structure and Performance Evaluation of Fractional Lower-Order Covariance Method in Alpha-Stable Noise Environments(Bentham Science Publishers B.V., 2019) Ahmed, Areeb; Savacı, Ferit AcarBackground: All existing time delay estimation methods, i.e. correlation and covariance, depend on second or higher-order statistics which are inapplicable for the correlation of alpha-stable noise signals. Therefore, fractional lower order covariance is the most appropriate method to measure the similarity between the alpha-stable noise signals. Methods: In this paper, the effects of skewness and impulsiveness parameters of alpha-stable distributed noise on fractional lower order covariance method have been analyzed. Results: It has been found that auto-correlation, i.e. auto fractional lower order covariance, \ of non delayed alpha-stable noise signals follows a specific trend for specific ranges of impulsiveness and skewness parameters of alpha-stable distributed noise. The results also depict that, by maintaining the skewness and impulsiveness parameters of alpha-stable noise signals in a certain suggested range, better auto-correlation can be obtained between the transmitted and the received alpha-stable noise signals in the absence and presence of additive white Gaussian noise. Conclusion: The obtained results would improve signal processing in alpha-stable noise environment which is used extensively to model impulsive noise in many noise-based systems. Mainly, it would optimize the performance of random noise-based covert communication, i.e. random communication.Article Citation - WoS: 10Citation - Scopus: 11Intersection of Microrna and Gene Regulatory Networks and Their Implication in Cancer(Bentham Science Publishers B.V., 2014) Yousef, Malik; Trinh, Hung V.; Allmer, JensMicroRNAs (miRNAs) have attracted heightened attention for their role as post-transcriptional regulators of gene expression. It has become clear that miRNAs can both up- and downregulate protein expression. According to current estimates, most human genes are harboring miRNAs and/or are regulated by them. Thus miRNAs form a complex network of expression regulation which tightly interacts with known gene regulatory networks. Similar to some transcription factors, some miRNAs can have hundreds of target transcripts whose expression they modulate. Thus miRNAs can form complex regulatory networks by themselves, but because their expression is often tightly coordinated with gene expression, they form an intertwined regulatory network with many possible interactions among gene and miRNA regulatory pathways. In this review we first consider gene regulatory networks. Then we discuss microRNAs and their implication in cancer and how they may form regulatory networks. Finally, we give our perspective and provide an outlook including the aspect of personalized medicine.Article Citation - WoS: 6Citation - Scopus: 6Bioactive Sphingolipids in Response To Chemotherapy: a Scope on Leukemias(Bentham Science Publishers B.V., 2011) Ekiz, Hüseyin Atakan; Baran, YusufSphingolipids are major constituents of the cells with emerging roles in the regulation of cellular processes. Deregulation of sphingolipid metabolism is reflected as various pathophysiological conditions including metabolic disorders and several forms of cancer. Ceramides, ceramide-1-phosphate (C1P), glucosyl ceramide (GluCer), sphingosine and sphingosine-1-phosphate (S1P) are among the bioactive sphingolipid species that have important roles in the regulation of cell death, survival and chemotherapeutic resistance. Some of those species are known to accumulate in the cells upon chemotherapy while some others are known to exhibit an opposite pattern. Even though the length of fatty acid chain has a deterministic effect, in general, upregulation of ceramides and sphingosine is known to induce apoptosis. However, S1P, C1P and GluCer are proliferative for cells and they are involved in the development of chemoresistance. Therefore, sphingolipid metabolism appears as a good target for the development of novel therapeutics or supportive interventions to increase the effectiveness of the chemotherapeutic drugs currently in hand. Some approaches involve manipulation of the synthesis pathways yielding the increased production of apoptotic sphingolipids while the proliferative ones are suppressed. Some others are trying to take advantage of cytotoxic sphingolipids like short chain ceramide analogs by directly delivering them to the malignant cells as a distinct chemotherapeutic intervention. Numerous studies in the literature show the feasibility of those approaches especially in acute and chronic leukemias. This review compiles the current knowledge about sphingolipids and their roles in chemotherapeutic response with the particular attention to leukemias. © 2011 Bentham Science Publishers Ltd.Article Citation - Scopus: 5Effect of Isotherm Shape on Mass Transfer in an Adsorbent Particle; an Isothermal Adsorption Process(Bentham Science Publishers B.V., 2011) Yıldırım, Zeynep Elvan; Gediz İliş, Gamze; Mobedi, Moghtada; Ülkü, SemraThe mass diffusion equation and corresponding initial and boundary conditions were non-dimensionalized for a spherical adsorbent particle in an infinite adsorptive medium to reduce number of independent governing parameters into two as mass transfer Biot number and dimensionless isotherm. The changes in local and average adsorbate concentration throughout the adsorption process were calculated and plotted for different values of mass transfer Biot numbers (ranging from 0.5 to 750) and for five different isotherm shapes. The obtained results indicated that the isotherm shape influences dimensionless period of adsorption, if the external mass transfer resistance is significant in the process. For those cases, the total dimensionless adsorption period for a convex shape isotherm is shorter than a concave one.Article Citation - Scopus: 31Quasi-Static Axial Crushing Behavior of Honeycomb-Filled Thin-Walled Aluminum Tubes(Bentham Science Publishers B.V., 2011) Aktay, Levent; Çakıroğlu, Cem; Güden, MustafaThe experimental and numerical quasi-static crushing behaviors of Nomex™ honeycomb-filled thin-walled Al tubes were investigated. The honeycomb filler was modeled using a unit cell model. The numerical model and experimental results have shown that, 6.4 mm and 4.8 mm cell size honeycomb filling had no effect on the deformation mode (diamond); however 3.2 mm cell size honeycomb filling changed the deformation mode to mixed/concertina. Honeycomb filling was also shown to increase the specific energy absorption of filled tubes over that of Al tube. The specific energy absorption of honeycomb filling was further compared with those of tube wall thickening and Al closedcell foam filling.