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3D-Printed Graphene-Based Bow-Tie Microstrip Antenna Design and Analysis for Ultra-Wideband Applications.(vol 13, 3724, 2021)
No full text[Abstract Not Available
A cross-cultural latent profile analysis of university students' cognitive test anxiety and related cognitive-motivational factors
No full textThe successful treatment of test anxiety treatment requires an understanding of the unique barriers and challenges faced by test-anxious students. Therefore, the current study utilized a combination of person-centered and qualitative methods to investigate the existence of unique subpopulations or subtypes of test-anxious students within Turkish and United States student samples. University students (N = 422) completed measures of cognitive test anxiety, self-efficacy, academic buoyancy, failure appraisal, academic self-handicapping, and goal commitment. Participants also completed open-ended questions assessing facilitators and inhibitors of academic success. The results of a multigroup latent profile analysis identified four learner subtypes in both the Turkish and United States samples. However, our analyses revealed structural differences in latent profiles identified in two cultural contexts. Furthermore, the qualitative results emphasized the importance of self-regulated learning, buoyancy, goal commitment, and self-actualization to academic success. Our discussion emphasizes the importance of considering learners' unique characteristics when designing educational supports. Students from both samples were found to be differentiated into unique subgroups, capturing a broad variation in test anxiety severity from low to moderate to high. One key takeaway for practitioners was the finding that students who question their ability to implement effective self-regulated learning strategies are prone to elevated test anxiety. Students' responses revealed noteworthy parallels with the quantitative results. Specifically, students characterized by elevated self-efficacy, effective regulation of their learning strategies, and unwavering commitment to academic goals were more likely to persist despite encountering academic setbacks. One notable pattern that was identified is the relatively consistent relationship between academic buoyancy and test anxiety observed across profiles within both cultural contexts
GERÇEKLİK PARADOKSU: GERÇEK ULAŞILAMAYACAK BİR YERDE
No full textBu çalışmada, felsefe tarihi boyunca etkisini hissettiren idea ve doğa arasındaki ayrımın izlerini sürüyorum. Söz konusu ayrıma vurgu yaparak gerçeklik anlayışımızın, paradoksal bir şekilde, doğrudan erişilmesi olanaklı olmayan bir doğası olduğunu göstermeye çalışıyorum. Var olan birçok gerilimin nedeninin, idea ve doğa arasında süregelen ayrım olduğunu söylemek çok da yanlış olmaz. Daha en baştan, fizik ve metafizik arasındaki fark bu ayrım perspektifinden anlam kazanır. Özel olarak, iç-dış, ben-dünya, özne-nesne, varlık-oluş, zihin-beden gibi ikiliklerin kökeninde idea ve doğa arasındaki ayrım bulunur. Genel olarak bakıldığında, ontolojik açıdan İdealizm-Realizm ve epistemolojik açıdan Rasyonalizm-Empirizm karşıtlığı da bu ayrımdan kaynaklanır. Çoğunlukla, gerçekliğe doğrudan erişilemeyeceği düşünülür. Doğası gereği dolaylı yollardan bilgisine ulaşabileceğimiz ve asla kolay ve doğrudan erişilecek gibi görünmeyen gerçeklik o halde ne kadar gerçeklik olarak adlandırılabilir? Pisagor ve Parmenides ile görünür olan, gerçekliğe doğrudan erişilemeyeceği iddiası, Platon, Descartes ve Kant gibi düşünürler tarafından da kabul edilir. Bugün modern sinirbilim de gerçekliğin (gerçek dünyanın bilgisinin) bir temsil/tasarım (representation) olduğu görüşünü savunur. Gerçekliğin zihinden bağımsız olması, ancak zihin tarafından bilinebileceği sorunludur. Benzer şekilde, gerçekliğe doğrudan erişilememesi, onun üzerinde işlem yapılarak bilinebileceği iddiası da sorunludur. Her iki durum da gerçekliğin kendinde halinden (in-itself) farklı olması varsayımı nedeniyle paradoksal görünmektedir
GSK2126458 yüklü polı kaprolakton (PCL) / polı vı nı lprrolı don (PVP) elektroeğrilmiş membranlar: Üretı m, karakterı zasyon ve antı kanser aktı vı te
No full textLisansüstü Eğitim Enstitüsü, Biyomühendislik Ana Bilim Dalı, Biyomühendislik Bilim DalıDeri kanseri, en tehlikeli kanser türlerinden biridir. Deri hücrelerinde oluşan DNA hasarının giderilememesiyle ortaya çıkan mutasyonlar sonucunda deride kanserli doku oluşumu görülebilmektedir. Deri kanseri insan vücudunda farklı bölgelere yayılma gösterebilen bir kanser türüdür ve iki ana gruba ayrılmaktadır: melanom ve melanom olmayan. Literatürdeki veriler melanom kanser türünün, deri kanseri vakalarının %1'ini oluşturduğunu belirtmektedir. Melanom deri kanserinin görülme sıklığı düşük olmasına rağmen hastaların ölüm oranları yüksektir. Deri kanseri tedavisinde farklı metotlar bulunmaktadır. Bu metotlardan en yaygın olanı biyopsi ve rezeksiyondur. Son yıllarda deri kanseri tedavisinde nanoteknoloji kullanımına ilgi artmıştır. Nanoteknoloji ile üretilen malzemeler molekül taşıyıcıları olarak kullanılmaktadır. Nanoteknolojik yöntemler kullanılarak üretilmiş membranlar ile ilacın spesifik bölgeye direkt uygulanabilmesi, daha hızlı tedavi ve azaltılmış yan etkiler elde edilmesi amaçlanmaktadır. Bu çalışmada, kanser ilacı olarak kullanılan GSK2126458 (Omipalisib®) ilacının elektroeğirme yöntemi ile elde edilen Polikaprolakton (PCL)/ Polivinilprolidon (PVP) fiber membranlar içerisine yüklenmesi ve melanom kanser hücre hattı üzerindeki etkilerinin incelenmesi amaçlanmıştır. Çalışma kapsamında elektroeğirme yöntemi ile GSK2126458 ilacını içeren, PCL/PVP/50 (50 µL ilaç ve 50 µL DMSO), PCL/PVP/75 (75 µL ilaç ve 25 µL DMSO) ve PCL/PVP/100 (100 µL ilaç) ve içermeyen PCL/PVP/C fiber membranlar üretilmiştir. Tüm örneklerde DMSO oranı sabit tutulmuştur. Üretilen fiber yapıların morfolojileri taramalı electron mikroskobu (SEM) ile kimyasal yapıları Fourier Transform Infrared Spectroscopy (FTIR) analizleri ile gerçekleştirilmiştir. Fiber çapları ve çap dağılımları SEM analizi ile elde edilen görüntülerden ImageJ program ile hesaplanmıştır. Fiber membranların su tutma özellikleri su temas açısı analizi ile mekanik özellikleri çekme-germe analizi ile belirlenmiştir. Üretilen fiber membranların antibakteriyel özelliklerinin belirlenmesi için E. coli, S. aureus, P. aeruginosa ve MRSA bakteri suşları üzerinde mikrobiyolojik analizler gerçekleştirilmiştir. Fiberlerin içerisine yüklenen GSK2126458 ilacının B16-F10 hücre hattı üzerindeki IC50 değeri resazurin analizi ile belirlenmiştir. İlacın fiber membrana eklendikten sonra melanom hücreleri üzerinde etkili olup olmadığı canlılık analizi, hücre morfolojisinin ve yayılma davranışının SEM analizi görüntülenmesi ve immünofloresan boyama ile araştırılmıştır. Tez çalışması sonucunda, GSK2126458 ilaç molekülü yüklenmiş ve ilaç içermeyen kontrol fiber membranlar düzgün ve boncuk içermeyen fiber yapısında elde edilmiştir. PCL/PVP/C, PCL/PVP/50, PCL/PVP/75 ve PCL/PVP/100 fiber gruplarının fiberlerinin ortlama çapları sırasıyla, 0.682?0,316, 0.588?0.240, 0.637?0.208 ve 0.611?0.196 µm olarak belirlenmiştir. PCL/PVP/C, PCL/PVP/50, PCL/PVP/75 ve PCL/PVP/100 fiber gruplarının su temas açısı analizleri sonucunda sırasıyla, 76.02?8.06, 83.63?1.75, 66.98?2.83 ve 82.92?12.82 dereceleri elde edilmiştir ve membranların hidrofilik yapıları gösterilmiştir. FTIR analizi ile PCL ve PVP polimerlerine spesifik pikler gösterilmiştir ancak ilaç molekülü için spesifik bir pik ilacın polimer yapısına gömülü olmasından dolayı elde edilememiştir. GSK2126458 ilacının B16-F10 fare melanom hücre hattı üzerinde IC50 değeri 49.21 µM olarak belirlenmiştir. İlaç yüklü membranlardaki hücre canlılığı ilaç içermeyen fiber membranlara göre analiz edildiğinde PCL/PVP/50, PCL/PVP/75 ve PCL/PVP/100 fiber membranlarda hücre canlılığının 24 saat için sırasıyla %72.25, %64.61 ve %57.82 (p<0.05) oldukları belirlenmiştir. 48 saat için ise sırasıyla, %74.76, %70.85 (p<0.05) ve %60.19 (p<0.01) oldukları belirlenmiştir. SEM görüntülerinde hücre yayılmasının kontrol grubunda diğer gruplara göre daha belirgin olduğu gösterilmiştir. Fiber membranlar üzerinde kültüre edilen hücrelerin fibröz aktin proteinin anti F-aktin antikoru ve çekirdeğinin DAPI ile boyanması ile elde edilen immünofloresan boyama görüntülerinde hücre yoğunluğunun artan ilaç molekülü miktarı ile azaldığı gösterilmiştir. Hücre çekirdeğinde belirgin değişiklikler görülmemiştir. Sonuç olarak, GSK2126458 ilacı yüklü PCL/PVP fiber membranların tez çalışması kapsamında başarı ile üretildiği ve B16-F10 fare melanom hücre hattı üzerinde etkili olduğu gösterilmiştir.Skin cancer is one of the most dangerous cancers. The mutations resulting from the failure to repair DNA damage in skin cells result in the formation of cancer tissue in the skin. Skin cancer is a type of cancer that can spread to different parts of the human body and is divided into two main groups: melanoma and non-melanoma. The data in the literature indicate that the type of melanoma cancer accounts for 1% of cases of skin cancer. Although the incidence of melanoma skin cancer is low, patients have high mortality rates. There are different methods of treating skin cancer. The most common of these methods are biopsy and resection. In recent years, interest in the use of nanotechnology in the treatment of skin cancer has increased. Materials produced by nanotechnology are used as molecular carriers. Membranes produced using nanotechnological methods are intended to enable the drug to be applied directly to a specific area, to faster treatment and to reduce side effects. In this study, it was aimed to load GSK2126458 (Omipalisib®), which is used as a cancer drug, into Polycaprolactone (PCL)/ Polyvinylprolidone (PVP) fiber membranes obtained by electrospinning method and to investigate its effects on melanoma cancer cell line. Within the scope of the study, PCL/PVP/50 (50 µL drug and 50 µL DMSO), PCL/PVP/75 (75 µL drug and 25 µL DMSO), PCL/PVP/100 (100 µL drug) and PCL/PVP/C fiber membranes containing GSK2126458 drug and PCL/PVP/C fiber membranes without drug were produced by electrospinning method. DMSO ratio was kept constant in all samples. The morphology of the produced fiber structures were analyzed by scanning electron microscopy (SEM) and their chemical structures were analyzed by Fourier Transform Infrared Spectroscopy (FTIR). Fiber diameters and diameter distributions were calculated from the images obtained by SEM analysis using ImageJ software. Water retention properties of the fiber membranes were determined by water contact angle analysis and mechanical properties were determined by tensile analysis. Antibacterial properties of the fiber membranes were determined using E. coli, S. aureus, P. aeruginosa and MRSA bacterial strains. The IC50 value of the GSK2126458 on B16-F10 cell line was determined by resazurin assay. The effect of the drug on melanoma cells after being added to the fiber membrane was determined by viability analysis, SEM analysis of cell morphology and spreading behavior and immunofluorescent staining. As a result of the thesis study, GSK2126458 drug molecule loaded and drug-free control fiber membranes were obtained in a smooth and bead-free fiber structure. The average diameters of the fibers of PCL/PVP/C, PCL/PVP/50, PCL/PVP/75 and PCL/PVP/100 membranes were calculated as 0.682?0,316, 0.588?0.240, 0.637?0.208 ve 0.611?0.196 µm, respectively. Hydrophilic structures of the membranes were shown by water contact angles of 76.02?8.06, 83.63?1.75, 66.98?2.83 ve 82.92?12.82 degrees for PCL/PVP/C, PCL/PVP/50, PCL/PVP/75 and PCL/PVP/100 fiber membranes, respectively. FTIR analysis showed specific peaks for PCL and PVP polymers, but a specific peak for the drug molecule could not be obtained because the drug was embedded in the polymer structure. The IC50 value of GSK2126458 on B16-F10 cell line was determined as 49.21 µM. When cell viability in drug-loaded membranes was analyzed compared to drug-free fiber membranes, it was determined that cell viability in PCL/PVP/50, PCL/PVP/75 and PCL/PVP/100 fiber membranes were 72.25%, 64.61% and 57.82% (p<0.05) for 24 hours, respectively. The viabilities were changed to 74.76%, 70.85% (p<0.05) and 60.19% (p<0.01) for 48 h, respectively. SEM images showed that cell spreading was more prominent in the control group than in the other groups. Immunofluorescence staining images obtained by staining fibrous actin protein of cells cultured on fiber membranes with anti F-actin antibody and nuclei with DAPI showed that cell density decreased with increasing amount of drug molecule. No significant changes were observed in the cell nucleus. In conclusion, it was shown that GSK2126458 drug loaded PCL/PVP fiber membranes were successfully produced within the scope of the thesis study and were effective on B16-F10 mouse melanoma cell line
Depolama Süresi ve Sıcaklığının Düşük Şekerli Turunç Kabuğu Marmelatının Fizikokimyasal ve Mikrobiyolojik Özelliklerine Etkisi
No full textBu çalışmada düşük şekerli turunç kabuğu marmelatının bazı fizikokimyasal ve mikrobiyolojik özellikleri üzerine depolama sıcaklığı ve süresinin etkisinin araştırılması amaçlanmıştır. Bu kapsamda şeker içeriği %30 azaltılmış ve yerine Steviol glikozit rebaudioside A (Reb A) ikame edilerek üretilmiş turunç kabuğu marmelatı iki farklı depolama sıcaklığında (5-6?/22-24?) 12 ay süre ile depolanmıştır. Depolama süresi boyunca suda çözünür kuru madde (SÇKM), pH, titrasyon asitliği (TA), su aktivitesi (aw) renk değerleri (L*, a*, b*, C* ve h°), 5-Hidroksimetilfurfural (HMF) ve toplam küf-maya analizleri gerçekleştirilmiştir. SÇKM değerleri 5-6? sıcaklıkta depolanan örneklerde artmış, 22-24?’de depolanan örneklerde ise depolama sonunda başlangıca göre %1,20 azalmıştır. Depolama başlangıcında 3,86 olan pH değeri 5-6?’depolama koşulunda 3,82’ye, 22-24? depolama koşulunda 3,83’e düşmüştür. Depolama sonunda su aktivitesi değerleri azalış gösterirken, titrasyon asitliği artış göstermiştir. Renk değerleri açısından incelendiğinde genel olarak depolama süresi boyunca marmelat örneklerinin L* ve hue açısı değerleri azalmış, a*, b* ve kroma değerleri artmıştır. HMF miktarı başlangıca göre depolama süresi boyunca artmış, bu artış 22-24?’de depolama sıcaklığında 57,53 kat, 5-6? sıcaklıkta 11,97 kat olarak gerçekleşmiştir. Depolama süresi içerisinde düşük şekerli turunç kabuğu marmelatında küf ve maya gelişimi gözlenmemiştir. Sonuç olarak, şeker içeriği %30 düşürülmüş turunç kabuğu marmelatının incelenen kalite parametreleri açısından 12 ay süre ile 5-6?’de muhafaza edilmesi tavsiye edilmektedir
A 19-Gene Signature of Serous Ovarian Cancer Identified by Machine Learning and Systems Biology: Prospects for Diagnostics and Personalized Medicine
No full textOvarian cancer is a major cause of cancer deaths among women. Early diagnosis and precision/personalized medicine are essential to reduce mortality and morbidity of ovarian cancer, as with new molecular targets to accelerate drug discovery. We report here an integrated systems biology and machine learning (ML) approach based on the differential coexpression analysis to identify candidate systems biomarkers (i.e., gene modules) for serous ovarian cancer. Accordingly, four independent transcriptome datasets were statistically analyzed independently and common differentially expressed genes (DEGs) were identified. Using these DEGs, coexpressed gene pairs were unraveled. Subsequently, differential coexpression networks between the coexpressed gene pairs were reconstructed so as to identify the differentially coexpressed gene modules. Based on the established criteria, SOV-module was identified as being significant, consisting of 19 genes. Using independent datasets, the diagnostic capacity of the SOV-module was evaluated using principal component analysis (PCA) and ML techniques. PCA showed a sensitivity and specificity of 96.7% and 100%, respectively, and ML analysis showed an accuracy of up to 100% in distinguishing phenotypes in the present study sample. The prognostic capacity of the SOV-module was evaluated using survival and ML analyses. We found that the SOV-module's performance for prognostics was significant (p-value = 1.36 x 10-4) with an accuracy of 63% in discriminating between survival and death using ML techniques. In summary, the reported genomic systems biomarker candidate offers promise for personalized medicine in diagnosis and prognosis of serous ovarian cancer and warrants further experimental and translational clinical studies.YOK 100/2000 Doctoral Fellowship ProgramThe scholarship under the YOK 100/2000 Doctoral Fellowship Program provided to Betul Comertpay is greatly acknowledged
SUPER-COUGH: A Super Learner-based ensemble machine learning method for detecting disease on cough acoustic signals
No full textSound classification has obtained considerable attention in recent years due to its wide range of applications in various fields, such as speech recognition, sound surveillance, music analysis, and environmental monitoring. Because of its success, audio classification can also be employed in medical applications. Coughing is the most common disease symptom, and cough sounds might be used to diagnose them. This research focuses on identifying observable features of cough and classifying them into positive, negative, or symptomatic categories. A novel ensemble learning model based on the super learner (SL) is proposed to diagnose the disease using cough sounds utilizing various audio features such as Frequency Distribution, Time Domain Features, Spectral Features, and Time-Frequency Features. The SL method is a cross -validated approach to stacked generalization, and it can select an optimal learner from a set of learners and improve performance by selecting and merging models using cross -validation. The proposed SL model comprises DT, RF, LR, SVM, ET, and k -NN algorithms. We use the public Coughvid dataset, and the proposed model achieves a correct classification rate for symptomatic cases, which was 90.90%, and the positive predictive value for COVID-19 cases was 84.50%. The SL3 model attains 72%, 78%, 73%, 74.4%, and 78.85% precision, recall, f1 -score, accuracy, and average AUC values, respectively. The numerical results show that the proposed model might be implemented to diagnose various other diseases that can be determined from respiratory sounds
Investigation of nanoparticle diameter influences on performance of hydrodynamic journal bearings operating with nanolubricant
No full textThe nanolubricant's effectiveness on the bearings' performance depends on the types of nanoparticles, volume ratio, and their size and/or diameter. Although the nanolubricant influences on the characteristics of the journal bearings are well known, cost-effective solutions for using nanolubricants, have continued to need in industrial applications. Because the nanoparticle's diameter plays a key role in the fluid with nanoparticle additives, research on its effect is important for hydrodynamic journal bearing. In this work, the nanoparticle diameter impacts on the characteristics of the hydrodynamic journal bearings are investigated with under thermal effects. At first, four hydrodynamic journal bearings have different parameters such as radial clearance and bearing length-diameter ratio are considered and designed. Then, the lubricant flow through the radial clearance is modeled with Dowson's equation. Besides, the temperature field in the journal and the lubricant are governed by the heat conduction and energy equations, respectively. The physical and thermal properties of the nanolubricant are expressed by considering nanoparticle diameter and the volume ratio. Then, an algorithm is developed to solve the mathematical models based on the finite difference method. Finally, a serial simulation is conducted under different nanoparticle diameters and operational conditions. When the nanoparticle diameter becomes small, the temperature and pressure values of the nanolubricant, load capacity, and stiffness increase
Evaluating the usability of recycled aggregates as fill materials depending on the composition and strength of their grains
No full textWhile recycling is a topic of contemporary relevance, there is a scarcity of research on the engineering characteristics of construction and demolition wastes with different levels of grain strength and composition of debris, which impose constraints on their potential for reuse. This study aims to increase the use of recycled aggregates in fillings, addressing a gap in the literature. For this purpose, large-scale direct shear and California bearing ratio tests were conducted on nine diverse recycled aggregates from different construction works. The test outcomes were compared to those obtained from natural aggregates (NA) to draw a meaningful conclusion. The impact of the specimens' water content and relative density on the findings was discussed. Results demonstrated that the shear strength of recycled aggregates is significantly affected by the compressive strength of the concrete within the recycled aggregates. Besides, increasing the percentage of NA or relative density improved the specimen's shear strength. On the other hand, it was determined that the high water content of the crushed bricks reduced the fill's quality. As a result of the study, equations were suggested for use in filling design
3D printed honeycomb transition metal decorated electrodes for hydrogen production
No full textIn this study, a PV-wind hybrid system was proposed as a power source for hydrogen production by alkaline electrolysis and it was examined MATLAB simulation for Adana region. In the alkaline electrolysis cell, lab-made 3D printed cathode substrates were used and its electrocatalytic activity was enhanced via electrodeposition of Ni, Cu and NiCu. The characterization was achieved via scanning electron microscopy, energy-dispersive X-ray, transmission electron microscopy, contact angle measurement and X-Ray diffraction analysis. The electrochemical performance was determined via linear sweep voltammetry, cyclic voltammetry, Tafel polarization measurements, electrochemical impedance spectroscopy, chronoamperometry. Results showed that 3DNiCu electrode exhibited nodular shaped homogeneous surface characteristics and NiCu (111) and (200) crystalline morphology; it also demonstrated lower polarization resistance and higher current density during alkaline electrolysis procedure.Adana Alparslan Turkes University Research fund [23101001]The authors are thankful to Adana Alparslan Turkes University Research fund for financial support (Project Number: 23101001)