TR-Dizin İndeksli Yayınlar Koleksiyonu

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https://hdl.handle.net/20.500.14669/4

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    DETERMINING TURKISH HOUSEHOLDS' TOURISM CONSUMPTION EXPENDITURES IN ECONOMIC CRISIS
    (Akdeniz Univ Tourism Fac, 2019) Gul, Hasan
    Crises may influence the most economies differently in the world and cause to diminish their national wealth and rise in unemployment rates. As a developing country, Turkey has been impressed by some economic slumps in the world in different periods. This study aims to investigate the tourism participation of households and estimate the most sensitive household groups after the 2008 financial crisis by employing Heckman two-stage model. It also reveals which household groups change their tourism consumption expenditures more in Turkey. The results show that variations in income elasticity during the crisis are different to household groups. In other words, households with high income level were not significantly affected by the world economic crisis, while households with low income reduced tourism consumption expenditures both in domestic and outbound tourism.
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    THE EFFECTS OF NEW EQUITY ANNOUNCEMENTS ON STOCK RETURNS: AN EXAMINATION ON BIST*
    (Economic And Financial Research Assoc - Efad, 2023) Unal, Cumali; Ergun, Bahadir
    The aim of this study is to examine the effect of rights and bonus issue announcements on stock returns. The study analyzes the companies included in the BIST-30 and BIST-50 indices between 2010 and 2022 and the companies that made capital increase announcements while they were included in these indices. In total, 84 different capital increase announcements of 35 companies were included in the study. In the study, the event study method was used and two different event windows were created as (-10, +10) and (-5, +5). At the end of the analysis, it was observed that new equity announcements affected stock returns. The study revealed that this effect was statistically significant negative. According to this situation, it can be said that the return expectations of the investors from the companies that announce the new equity issue should be negative and they should arrange their portfolios according to this result. According to the results of the research, it has been revealed that Borsa Istanbul is an inefficient market in semi-strong form.
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    Quantitative variation of phenolic compounds in different tissues of pistachio ( Pistacia vera L. cv. Uzun) associated with alternate bearing
    (Tubitak Scientific & Technological Research Council Turkey, 2024) Guney, Mujgan; Gundesli, Muhammet Ali; Guney, Murat; Kafkas, Nesibe Ebru; Kafkas, Salih; Ergun, Zeynep
    Alternate bearing is a common challenge in horticultural plants, leading to irregular yield in successive years. The potential role of phenolic compounds in regulating this phenomenon, however, is not well understood. This study aimed to investigate the potential role of phenolic compounds in alternate bearing in pistachio trees by analysing samples from different parts of the Uzun cultivar over two consecutive years. Seven phenolic compounds (gallic acid, p-coumaric acid, caffeic acid, ferulic acid, chlorogenic acid, catechin, and quercetin) were analysed using high-performance liquid chromatography at 10-day intervals. Significant variations were observed in the levels of certain phenolic compounds between ON and OFF years, suggesting a potential role for these compounds in alternate bearing. Ferulic acid exhibited a significant decrease in leaves and shoots, indicating its translocation to the nuts, leading to a sharp decline during the nut lignification process. A negative and significant correlation between ferulic and caffeic acid levels was observed in the ON and OFF years, which may be linked to the alternate bearing and kernel development process in pistachio. These findings provide valuable insights into the role of phenolic compounds in regulating alternate bearing in pistachio trees and could inform future strategies for enhancing pistachio yields and quality.
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    FLOW CONTROL OF A CIRCULAR CYLINDER BY PERMEABLE SPLITTER PLATE WITH DIFFERENT POROSITIES AND ANGLE VALUES
    (Turkish Soc Thermal Sciences Technology, 2024) Sahin, Serdar; Durhasan, Tahir; Pinar, Engin; Akilli, Huseyin
    Flow control of bluff bodies has been studied extensively to eliminate adverse effects of wake flow such as vibration and acoustic noise or resonance. The circular cylinder has been studied as the bluff body since it is basic geometry and has been used in engineering applications such as heat exchanger tubes, power transmission lines, chimney stacks, bridges, radio telescopes, power lines, offshore drilling rigs etc. In this study, a permeable splitter plate was located at various downstream locations to control the wake flow of the cylinder. All experiments were carried out in a large-scale closed-loop water channel in the Fluid Mechanics Laboratory at Cukurova University. PIV was used to measure the instantaneous velocity vector field in the wake region of the cylinder at Reynolds number Re=5000, which is based on the cylinder diameter, D. Four different splitter plate angle values (0 =0 degrees; 15 degrees; 30 degrees; 45 degrees), three different porosity values (epsilon=0.30; 0.50; 0.70) were investigated. The porosity (epsilon) of the separator plates is defined as the ratio of the total hole area to the plate surface area. All lengths are nondimensionalized by dividing by the cylinder diameter and shown with the * index. The splitter plate length kept to constant during the experiment as ls*=1. The distance between the leading edge of the splitter plate and the cylinder (lg*) is variable due to the rotation of the separator plate at certain angles in the flow direction. To overcome this, the distance between the splitter plate rotation axis and the cylinder was taken as a parameter and shown with the **. The gap between splitter plate midpoint and cylinder (lg**) kept to constant during the experiments as lg**=1.5. When the plates are rotated, the cross-section parallel to the flow decreases, which increases the interaction between the boundary layers. Since the permeable separator plates prevent the interaction of the boundary layers formed in the flow around the cylinder, the effect of the permeable separator plates increases in the downstream regions where the interaction of the boundary layers increases. Thus, the fluctuations are reduced, and a more stabilized trail flow occurs downstream of the cylinder. It was observed that the vortex formation was delayed with the increase of the separator plate angle. In this study, the effect of the separator plate angle and the effect of the plate permeability were clearly observed.
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    Seed oil content and fatty acid profiles of endemic Phoenix theophrasti Greuter, Phoenix roebelenii O'Brien, Phoenix caneriensis Hort. Ex Chabaud, and Phoenix dactylifera L. grown in the same locality in Turkey
    (Tubitak Scientific & Technological Research Council Turkey, 2021) Ergun, Zeynep
    Plants-based oils and fats usually obtained from seeds have been indispensable substances for mankind, both in nutritional and industrial respect. This study aimed to determine the total amount of oil and the fatty acid compositions of Phoenix theophrasti Greuter, P. roebelenii O'Brien, P. caneriensis Hort. Ex Chabaud, and P. dactylifera L. The seeds of these four Phoenix species were collected from the same location, east Mediterranean agroecological conditions when the fruits were fully ripened, which means the environmental factors that may affect the oil content and the fatty acid compositions were controlled. The highest oil content of the samples was obtained from P. caneriensis (8.435 g/100 g) and followed by P. dactylifera (6.400 g/100 g), P. roebelenii (5.130 g/100 g), and P. theophrasti (4.730 g/100 g), respectively. The dominant fatty acids detected in the seed oils were oleic acid (C18:1n9c, 35.080-46.625%), lauric acid (C12:0, 26.160-18.055%), myristic acid (C14:0, 12.670-10.335%), linoleic acid (Cl8:2n6c, 13.295-7.990%), and palmitic acid (C16:0, 11.355-7.590%) for all four species. To the best of the knowledge, this study is the first to reveal the total oil amount of the seeds of P. theophrasti and P. roebelenii, and also the fatty acid composition of P. roebelenii.
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    MARKET SEEKING OF AMERICA IN MERSIN IN THE LATE OTTOMAN PERIOD
    (E.U. Printing And Publishing House, 2024) Ulutas, Songul; Kanat, Vedat
    The capitalist economy and industrial revolution developments, dominated the world conjuncture in the 19th century, formed the political infrastructure of European states. The gradual development of production technologies with the industrial revolution caused western countries to search for markets to sell manufactured goods and raw materials to put production technologies into practice. Commercial firms were marketing their products through intermediary firms or individuals by determining the target market they identified. They run a series of promotional campaigns to make the products or services of companies preferred by people. How these marketing techniques were used by American companies in Mersin, which was a quite new and open port to growth and demand in the late 19th and early 20th centuries, can be found in the letters of American Consulate. The knowledge about the marketing techniques applied by American companies, has been obtained from the letters of the American Consulate. The aim of the study is to reveal how the search for the market in Mersin, a port city, which was open to growth in the late 19th century and early 20th century, was carried out by these numerous American companies.
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    Food Purchasing Behavior of Y Generation Consumers
    (Kahramanmaras Sutcu Imam Univ Rektorlugu, 2018) Dolekoglu, Celile O.; Celik, Onur
    Developments in the aging world are called as a milestone. The industrial revolution, the great depression, the world wars, and the technological revolution, all, have been an age characteristic for the last 150 years. These ages have revealed differences in the way of life and buying behavior of society. The determination of these differences is important for the decision-makers of business's, marketing, human resources, production units. Since the common characteristics among the born in the same period the term new generation is used for each generation. The reality of each generation is that their values, attitudes, behaviors, social life, consumption, habits, the difference of world view can not be rejected. The period that we live in is dominated by the generation Y and followed by the Z generation. In the last 50 years, the increase of population in the world has led to a large increase in the Y generation and become the Y generation the world's largest population. It is also important to know and determine the place of consumption of food products and services in the fast consumption habits of this young consumer group. In this study, a questionnaire was conducted with 300 people living in the center of Adana in the age of 18-37 in order to determine the general decision making and behavior of food products of this generation which constitutes a significant part of the consumers. Overall, 50.7% of the participants are women and 45.7% are full-time workers; 60.7% of the participants spend-at least once a week-out of home for food and 84% of the participants spend 100-500 TL monthly for food. Meat-based traditional cuisine (kebab, liver, doner, etc.) was the most preferred type of food. The sample group consists of people who are not innovative in food products but who accept healthy nutrition only in discourse but who are known conscious about food reliability.
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    Dynamic analysis of moderately thick composite cylindrical panel subjected to moving load
    (Gazi Univ, Fac Engineering Architecture, 2018) Kurtaran, Hasan
    In this study, dynamic behavior of moderately thick symmetrically laminated composite cylindrical panel under moving load is investigated using Ritz solution approximations. Hamilton's principle (also referred to as dynamic version of Virtual work principle) is used to derive the equation of motion. First order shear deformation theory is used to consider transverse shear effect. Time integration of equation of motion is carried out using implicit Newmark average acceleration method. Parametric study is conducted in order to investigate the dynamic behavior of composite cylindrical panel for different velocities of moving load, curvature ratios, stacking schemes and boundary conditions.
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    AN EVALUATION ON DEFENSE STRUCTURES IN CATALCA REGION
    (E.U. Printing And Publishing House, 2021) Efeoglu, Melik; Eyupgiller, Kemal Kutgun
    Human beings, who want to protect themselves against threats and dangers that may come from outside, have researched and developed different defense methods throughout history. This search, which has become a necessity in the historical process, has led to the emergence of different defense practices and defense structures. Defense structures, which are one of the important sources that shed light on the experiences of past civilizations and one of the building blocks of the architectural heritage, allow access to information about the defense history and technologies of societies, as well as contribute to comment on their social, cultural and economic structures. These defensive structure, which were built to protect from various effects of nature, predators or aggressive groups starting from the primitive periods, differ depending on the development level of the societies and the geographical features of the region. Changing combat techniques and technologies have accelerated the transformation, renewal and development of defense structures in the process. Catalca Region has an important area among the military architectural heritage sites in terms of the originality and diversity of its historical defense structures. The defense structures in the region are cultural properties that represent the military architecture and defense strategy of the period they were built. This study, which investigates the historical defense structures in the Catalca Region, consists of three sections. In the first part, changes in defense structures through historical process were discussed. Also, the elements that trigger the development of defense structures were briefly handled. In the second part, in parallel with the development of defense structures in the historical course, defense structures in the Catalca Region were addressed. The history and architectural features of the defense structures in the region were tried to be emphasized. In the last part, a general evaluation was made on these defensive structures and their current situation and the conservation problems identified following the fieldworks were pointed out. The defense structures discussed in this study and located in the Catalca Region are the products of three different periods and are rare examples that reflect the evolution of defense structures in the historical process. These structures, which reveal the geopolitical importance of the Catalca Region, form the defense lines extending from the Black Sea to the Marmara Sea in the north-south direction. These defense structures, which took an active role to defend Istanbul during the period they were built, face the danger of extinction today due to various protection problems. Considering the number and type of historical defense structures in the region, the importance of the Catalca Region in terms of our defense history is understood. However, the fact that most of the historical defense structures in the region have not been legally protected and comprehensive conservation works have not been carried out for these structures, shows that the awareness about the military architectural heritage is not at the desired level. In this context, it is aimed to bring the historical and architectural values of these defense structures to light and to raise awareness on the issue by drawing attention to conservation problems.
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    Scaffolds from medical grade chitosan: A good choice for 3D cultivation of mesenchymal stem cells
    (Tubitak Scientific & Technological Research Council Turkey, 2022) Yurtsever, Merve Capkin; Akdere, Ozge Ekin; Gumusderelioglu, Menemse
    Chitosan has high biocompatibility, supports proliferation of many cells, and can be a good carrier for various growth factors. However, low attachment ratio and spheroid formation of several stem cell types on plain chitosan scaffolds/films is still a problem. In this study, it was aimed to obtain 3D scaffolds using medical grade chitosan (MC) with a high deacetylation degree (DD >= 92.6%) to overcome the spheroid formation of rat adipose tissue derived mesenchymal stem cells (rAdMSCs) on control chitosan (C, DD = 75%-85%) scaffolds. Genipin was used as a biological chemical crosslinker, and glycerol phosphate salt was used both as a pH adjusting agent and physical crosslinker. MTT and SEM analyses and live/dead staining indicated the increase in the attachment, cell viability, and proliferation of rAdMSCs on MC scaffolds with or without crosslinking when compared to the cells in spheroid formation on control scaffolds. Moreover, filamentous actin protein organization of rAdMSCs was found to be triggered on the crosslinked MC scaffolds. In conclusion, plain medical grade chitosan scaffolds with or without crosslinking prevented spheroid formation, supported the attachment, proliferation, and organization of rAdMSCs indicating that medical grade type of chitosan scaffolds with high DD can be a very good candidate as 3D carriers in stem cell cultivation.
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    Novel stability and passivity analysis for three types of nonlinear LRC circuits
    (Ramazan Yaman, 2021) Ates, Muzaffer; Kadah, Nezir
    In this paper, the global asymptotic stability and strong passivity of three types of nonlinear LRC circuits are investigated by utilizing the Lyapunov's direct method. The stability conditions are obtained by constructing appropriate energy (or Lyapunov) function, which demonstrates the practical application of the Lyapunov theory with a clear perspective. Many specialists construct Lyapunov functions by using some properties of the functions with much trial and errors or for a system they choose candidate Lyapunov functions. So, for a given system the Lyapunov function is not unique. But we insist that the Lyapunov (energy) function is unique for a given physical system. Thus, this study clarifies Lyapunov stability with suitable tools and also improves some previous studies. Our approach is constructing energy function for a given nonlinear system that based on the power-energy relationship of the system. Hence for a dynamical system, the derivative of the Lyapunov function is equal to the negative value of the dissipative power in the system. These aspects have not been addressed in the literature. This paper is an attempt towards filling this gap. The provided results are central importance for the stability analysis of nonlinear systems. Some simulation results are also given successfully that verify the theoretical predictions.
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    Cevresel kent kimli?i uzerine mekansal bir okuma: Kulturel miras olarak pullar?n kent belle?indeki yeri
    (Yildiz Technical Univ, Fac Architecture, 2022) Durgun Sahin, Yelda
    Turkiye is a unique country with its natural beauties, historical and archaeological heritage, so-cio-cultural life. Each of these characteristics gives a local urban identity for each city. The Great Country Cities series of postage stamps in the Republic of Turkiye belonging to 67 cities showing the photographs of the cities were printed between 1958-1960. Stamps as an inventory and a tool for urban memory express our national identity. By creating stamp illustrations that show the natural and artificial environment of cities, they have become a visual communication tool that allows cities to be promoted and reach a wide audience. In this study, which is about environmental identity analysis, it is selected the Great Country Cities series of postage stamp to study the perception of the city of the photographer(s).The intuitive approach of the photographer while photographing the urban environment has led to the promotion of cities by reaching large audiences through stamps. This study aims to reveal the perception of the urban environment that influences these artists' decisions when photograph-ing cities. Therefore, the study is carried to determine the environmental identity components and image elements of the urban area on the city stamps. Thus, the perception of the city by the artist who photographs cities would be revealed. This study evaluated the artist's perception when these stamps were photographed. There are three stages to the study. In the first stage, the city stamps are grouped regionally and the envi-ronmental identity elements are analysed according to the city image components. In the sec-ond stage, the Analytical Hierarchy Process (AHP) method is used to determine the weights of the criteria constituting the environmental identity. At the third stage, the perception of urban identity (environmental) that the artist/artists who photographed cities wanted to emphasise about that cities were evaluated comparatively with weighted criteria. At the end of the study, it is seen that the environmental urban identity perception has regional differences, and the image elements of the cities are revealed. When the regional analysis findings were compared with the AHP method; It is seen that the order of the criteria weights of the artificial environment com-ponents and the order of the graphical reading (findings obtained in accordance with the Gestalt theory and Lynch city image component analysis) findings, which are considered regionally, are the same. When the natural environmental components are examined regionally; in all regions,
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    Investigation of Zn recovery from Balıkesir Balya Pb-Zn ore by hydrometallurgical methods
    (Gazi Univ, Fac Engineering Architecture, 2024) Tombal, Tugba Deniz; Kursun, Lgin
    In this study, the recovery of Zn from Bal & imath;kesir-Balya Pb-Zn ores by acid leaching method was investigated. H2SO4, HCl and HNO3 were used as solvent reagents in leaching processes. According to the results obtained, optimum conditions were defined for each acid and the most suitable acid for the leaching methodwas determined considering its dissolution efficiency (Table A). In addition, temperature-dependent kinetic analyzes were performed for all three acids in this study. In this context, in order to determine the kinetic model controlling the total reaction rate, the situations under the chemical controlled model, diffusion controlled model, and film diffusion model were examined separately and appropriate kinetic models were determined for each acid.
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    A thermohydrodynamic performance analysis of a fluid film bearing considering with geometrical parameters
    (Yildiz Technical Univ, 2023) Dal, Abdurrahim; Sahin, Mahir; Kılıç, Mustafa
    Bearing performance characteristics such as stiffness, and load capacity, are related to the lubrication fluid circulating through the gap. In the fluid film bearings, the characteristic of the lubrication film also depends on the journal geometry and the viscosity. This study aimed to research the bearing geometry influences on the thermohydrodynamic performance of a circular journal bearing. The temperature distribution is modeled using a 3-dimensional energy equation. The velocity components are obtained on the pressure distribution governed by Dowson's equation. Moreover, the heat transfer between the journal and oil is modeled with Fourier heat conduction equation, and the viscosity equation is derived for SAE10W30 commercial oil as a function of the temperature. An algorithm based on the finite difference method is developed, and a serial simulation is performed for different geometrical parameters such as bearing clearance, and bearing length-to-diameter ratio (L/D). When the radial clearance decreases from 150 i.tm to 100 i.tm, the maximum pressure grows up by 53%, and the maximum temperature decreases by 21%. On the other hand, when the L/D ratio rises from 0.8 to 1, the maximum pressure grows up by 22%, but the temperature distribution does not significantly change. The load capacity, and the stiffness are higher for low radial clearance. The load capacity, and the stiffness increase when the L/D ratio grows up.
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    The comparative analysis of SPACE SYNTAX and PPS approaches in measuring quality of urban space: The case of Beyazit district, Istanbul
    (Yildiz Technical Univ, Fac Architecture, 2022) Gumus, Imran; Acik Etike, Buse; Parlakyildiz Kose, Istem Seckin
    Spatial quality research is conducted using quantitative and qualitative research methods and techniques such as observation or surveys. The aim of the study is to make a comparative analysis of two research methods; the space syntax method, which focuses on a spatial configuration, and the Project for Public Spaces (PPS) approach, which focuses on the quality of urban spaces through principles defined as sociability, linkages and access, uses and activities, comfort and image, which enable understanding the socio-cultural characteristics of the area. This study uses these two methods to examine the concept of quality in urban space in order to measure the spatial quality of Beyazit Square and its surroundings in the historical peninsula of Istanbul. As a result, space syntax numerical values of integration, connectivity and intelligibility can be used as data for measuring the quality of urban space. However, there are differences between the PPS results and the spatial configuration data. This difference enables the identification of quality parameters that are dependent on and independent of the spatial configuration. Through this combined approach, the impact of spatial configuration on spatial quality is investigated. It is concluded that the combination of these two methods can provide a new alternative approach for comprehensive and reliable results in the quality measurement of urban spaces.
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    mlCoCoA: a machine learning-based congestion control for CoAP
    (Tubitak Scientific & Technological Research Council Turkey, 2020) Demir, Alper Kamil; Abut, Fatih
    Internet of Things (IoT) is a technological invention that has the potential to impact on how we live and how we work by connecting any device to the Internet. Consequently, a vast amount of novel applications will enhance our lives. Internet Engineering Task Force (IETF) standardized the Constrained Application Protocol (CoAP) to accommodate the application layer and network congestion needs of such IoT networks. CoAP is designed to be very simple where it employs a genuine congestion control (CC) mechanism, named as default CoAP CC leveraging basic binary exponential backoff. Yet efficient, default CoAP CC does not always utilize the network dynamics the best. As a result, CoCoA has been exposed to better utilize the IoT networks. Although CoCoA considers the network dynamics, the RTO calculation of CoCoA is based on constant coefficient values. However, our experiments show that these constant values, in general, do not achieve the best throughput. Inspired by these observations, we propose a new machine learning-based CC mechanism called as mlCoCoA that is a variation of CoCoA. Particularly, mlCoCoA sets retransmission timeout (RTO) estimation parameters of CoCoA adaptively by using a machine learning method. In this study, we applied support vector machines on a self-created dataset to develop new models for improving the throughput of the IoT network with dynamic selection of CoCoA coefficient values. We carried out extensive simulations in Cooja environment coupled with Californium. Our results indicate that compared to the performance of default CoAP CC and CoCoA mechanisms, mlCoCoA has merit in terms of improving the throughput of CoAP applications.
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    A numerical investigation of combined effect of nanofluids and impinging jets for different parameter
    (Gazi Univ, Fac Engineering Architecture, 2019) Kılıç, Mustafa; Ozcan, Okan
    In this study; enhancement of heat transfer on a high heat-flux surface is investigated numerically by using nanofluids with impinging jet technique. Heat transfer from flat copper surface was studied for different Reynolds number (Re=12000, 14000, 16000, 18000), different particle diameter of nanofluid (Dp=10nm, 20nm, 40nm, 80nm), different volume fraction of nanofluid (phi=% 2, % 4, % 6, % 8), and different types of nanofluids (CuO-water, NiO-water, Cu-water, pure water). The low Reynolds number k-e turbulence model of the PHOENICS CFD program was used in the study. As a result; increasing Re number from 12000 to 18000 resulted in an increase of 28% on average Nusselt number. It has been obtained that decreasing particle diameter from 80nm to 10nm causes an increase of 13.20% on average Nusselt number. It has been determined that increasing volume ration more than 4% does not cause a significant increase in heat transfer. In the case of using different types of nanofluids, the best heat transfer performance is obtained when Cuwater nanofluid is used. Using Cu-water nanofluid showed an enhancement of 8.3% on average Nusselt number compared to pure water. Moreover; it has been shown that the low Reynolds number k-epsilon turbulence model can well represent the temperature distribution and flow properties.
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    Pterostilbene suppresses head and neck cancer cell proliferation via induction of apoptosis
    (Tubitak Scientific & Technological Research Council Turkey, 2024) Ozdas, Talih; Ozdas, Sibel; Canatar, Ipek; Kaypak, Erdem
    Background/aim: Head and neck cancer (HNC) is one of the most prevalent causes of death worldwide, and so discovering anticancer agents for its treatment is very important. Pterostilbene (PS) is a trans-stilbene reported to be beneficial in managing various cancers. The objective of the study was to evaluate the cytotoxic, antiproliferative, proapoptotic, and antimigrative effect of PS on HEp-2, SCC-90, SCC-9, FaDu, and Detroit-551 cell lines. Materials and methods: MTT and live/dead assays were employed to assess cell viability, while a cell migration test was performed to evaluate wound healing capacity. The mRNA, protein, and intracellular expression levels of CASP-3, BAX, and BCL-2 genes were evaluated by real-time PCR, western blotting, and immunofluorescence staining. Annexin V-PI staining was conducted to assess the amounts of viable, apoptotic, and necrotic cells. Results: The results revealed that PS displayed cytotoxic, antiproliferative activity in a dose-dependent manner in HNC cells by upregulating CASP-3 and BCL-2 while downregulating BCL-2 in the apoptotic pathway. The proapoptotic properties were confirmed by the annexin-V-IP results. Moreover, PS displayed a significant suppressive efficacy on the migration capacity of HNC cells. Conclusion: The present study provides proof that PS has the prospective to be improved as an attractive anticancer agent against HNC following advanced studies.
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    Crm1 knockdown by specific small interfering RNA reduces cell proliferation and induces apoptosis in head and neck cancer cell lines
    (Tubitak Scientific & Technological Research Council Turkey, 2018) Ozdas, Sibel; Ozdas, Talih
    Head and neck squamous cell carcinoma (HNSCC) is the most common and most aggressive type of head and neck cancer. Current approaches for the treatment of HNSCC are not sufficient to increase the patient survival or to reduce the high recurrence rate. Consequently, there is a need to explore the molecular characteristics of this cancer in order to discover potential therapeutic target molecules. The overexpression of chromosome region maintenance 1 (Crm1), responsible for the transport of different classes of macromolecules from the nuclear membrane to the cytoplasm, in various cancer cells has made it an attractive target molecule in cancer research. It has been reported that transcription factors, which are the target cargo proteins of Crm1, have critical roles in regulating intracellular processes via their expression levels and functions, which in turn are regulated by the cell cycle and signaling proteins. Previous findings show that head and neck cancer cells overexpress Crm1 and that these cells become highly dependent on Crm1 function. The results of this study show that after decreasing Crm1 expression levels in HNSCC cells through either treatment with specific Crm1 RNA interference (siRNA) or the selective Crm1 inhibitor leptomycin B (LMB), cell viability, proliferation, migration, and wound-healing abilities decreased, suppressing tumorigenic properties through the induction of apoptosis. Crm1 is a powerful diagnostic biomarker because of its central role in cancerogenesis, and it has a high potential for the development of targeted Crm1 molecules or synthetic agents, such as LMB, as well as for the improvement of the clinical features in head and neck cancer.
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    Estimation of hourly global solar radiation using artificial neural network in Adana province, Turkey
    (Yildiz Technical Univ, 2021) Goncu, Onur; Koroglu, Tahsin; Ozdil, Naime Filiz
    Since global solar radiation (GSR) is an important parameter for the design, installation, and operation of solar energy-based systems, it is important to have precise information about it. As the indicating devices are expensive and their requirements such as operation and maintenance should be carried out, the measurement of solar radiation cannot be frequently taken. On the other hand, the measurements of different meteorological parameters such as relative humidity and ground surface temperature are more prevalent in meteorology stations. Therefore, the estimation of solar radiation is a significant parameter for the areas where the measurements could not be performed and to complete the missing information in databases. Many different models, software, and simulation programs are utilized to calculate solar radiation data, provide an economic advantage, and obtain high accuracy. The main purpose of this study is to perform an estimation of solar radiation in Adana, where is on the east of the Mediterranean in Turkey, by using an artificial neural network (ANN) model. The best estimation performance is obtained by optimizing the neuron numbers used in the network's hidden layer with the trial and error method. With this aim, hourly data including wind speed, wind direction, humidity, actual pressure, and average temperature are taken as inputs while solar radiation is taken as a target. All these data, which is for 2018, has taken from the Turkish State Meteorological Service. A linear correlation coefficient value has been obtained to be about 0.87313 with the mean square error (MSE) of 5.8262x10(7) W/m(2) for the testing data set. The ANN's testing/validation results show that it has a low MSE, indicating the accuracy and adequacy of the network model. Besides, the predicted ANN output is evaluated to be remarkably close to the measured target data by considering the linear correlation coefficient.