Atılım Academic Archive (Atılım University)
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Outcomes of Transcatheter Aortic Valve Implantation in Patients With and Without Diabetes Mellitus
No full textKeles, Telat/0000-0001-5372-8351Introduction: Diabetes mellitus (DM) in patients undergoing cardiac transcatheter or surgical interventions usually is correlated with poor outcomes. Transcatheter aortic valve implantation (TAVI) has been developed as a therapy choice for inoperable, high-, or intermediate-risk surgical patients with severe aortic stenosis (AS). Objective: To evaluate the impact of DM and hemoglobin A1c (HbA1c) on outcomes and survival after TAVI. Methods: Five hundred and fifty-two symptomatic severe AS patients who underwent TAVI, of whom 164 (29.7%) had DM, were included in this retrospective study. Follow-up was performed after 30 days, six months, and annually. Results: The device success and risks of procedural-related complications were similar between patients with and without DM, except for acute kidney injury, which was more frequent in the DM group (2.4% vs. 0%, P=0.021). In-hospital and first-year mortality were similar between the groups (4.9% vs. 3.6%, P=0.490 and 15.0% vs. 11.2%, P=0.282, respectively). There was a statistical difference between HbA1c >= 6.5 and HbA1c = 6.5 (HR 10.78, 95% CI 2.58-21.50; P=0.003) in multivariable logistic regression analysis. Conclusion: In this study, we conclude that DM was not correlated with an increased mortality risk or complication rates after TAVI. Also, it was shown that mortality was higher in patients with HbA1c >= 6.5, and it was an independent predictor for long-term mortality.Science Citation Index Expande
A Model for the Prediction of Thermal Runaway in Lithium-Ion Batteries
Get PDFAzuaje-Berbeci, Bernardo J./0000-0002-6773-3087The increasing popularity of electric vehicles is driving research into lithium -ion batteries (LIBs). Thermal runaway (TR) in LIBs is a serious concern for the safe operation of these high-energy-density batteries that is yet to be overcome. A reliable model is needed to predict voltage variation, heat generation, temperature rise, and the process leading to TR of a LIB battery under its operating conditions (charging-discharging). Such a model can be used to design battery packs more resilient to thermal runaway or assess how a battery pack would perform under hazardous conditions. Furthermore, it can be used for generating a warning signal if there is a possibility of the battery going towards TR. This paper presents an approach to solving this problem, which is not currently well addressed in the literature. The approach adopted in this paper is based on a numerical analysis of a multilayered electrochemical-thermal model of LIB. Tuning the parameters of a LIB for accurate results from this numerical model is presented, as well as the details of the approach in the paper. Experiments are performed under several LIBs, and their voltage and surface temperature variations are measured under various operating conditions, including thermal runaway. The results of the experiments are compared with the predictions of the numerical simulations. An excellent agreement is observed with the experimental results, proving the accuracy of the proposed approach. This approach can be configured to give results in a few minutes. The paper also discusses how the developed approach can be used to create a TR warning during operating conditions or to change the mode of operation of a LIB before a hazard occurs
Satellite Constellations in International Law
Get PDFUzay, insanlığın keşfetme arzusu ve teknolojik ilerlemesiyle sonsuz bir potansiyele sahip bir ortam olarak her geçen gün daha fazla önem kazanmaktadır. Ancak uzayın bazı sınırlı kaynakları ve çevresel hassasiyetleri, bu alandaki faaliyetlerin düzenlenmesini ve denetlenmesini gerektirmektedir. Bu bağlamda takım uyduların uluslararası hukuk açısından incelenmesi, uzayın müspet hukuki çerçevesindeki eksikliklerin belirlenmesi ve çözümler önerilmesi gereken önemli bir konu olarak ortaya çıkmaktadır. Sürdürülebilir kalkınma için oldukça büyük katkılar sunan ve görece çok daha düşük maliyetler ile uzay temelli hizmetlerin verilmesinin bir yolu olan takım uyduların kontrolsüz çoğalması birtakım potansiyel tehdit barındırmaktadır. Özellikle mega takım uydu girişimlerinin ortaya çıkışı sonrasında, ele alınma gerekliliği giderek artan üç temel mesele; uzay enkazının azaltılması, karanlık gökyüzünün korunması ve radyo enterferansının önlenmesi, bu çalışma kapsamında incelenen esas potansiyel tehditler olmuştur. Takım uydular a uygulanabilecek uluslararası hukuki rejim, Birleşmiş Milletler uzay andlaşmaları ve Uluslararası Telekomünikasyon Birliği düzenlemeleri çerçevesinde ele alınmıştır. Daha sonra, sürdürülebilir uzay faaliyetleri için önem arz eden uzay enkazı, ışık kirliliği ve zararlı enterferans sorunları incelenmiş; bu sorunlar için bağlayıcı olmayan kılavuzlar ve ulusal mevzuatlardaki yaklaşımlar ön plana çıkarılarak çözüm önerilerinde bulunulmuştur.Space, with its infinite potential driven by humanity's desire for exploration and technological advancement, is gaining increasing importance each day. However, the limited resources and environmental sensitivities of space necessitate the regulation and oversight of activities in this domain. In this context, the examination of satellite constellations from an international legal perspective emerges as a significant issue, requiring the identification of deficiencies in the positive legal framework of space and the proposal of solutions. The uncontrolled proliferation of satellite constellations, which offer substantial contributions to sustainable development and the provision of space based services at relatively lower costs, poses some potential threats. Particularly following the emergence of mega constellation initiatives, three fundamental issues requiring attention have increasingly arisen: space debris mitigation, preservation of the dark sky, and prevention of radio interference, which constitute the primary potential threats examined in this study. The international legal regime applicable to satellite constellations has been examined within the framework of United Nations space treaties and International Telecommunication Union regulations. Subsequently, issues critical to sustainable space activities, such as space debris, light pollution, and harmful interference, have been analyzed. For these issues, non binding guidelines and approaches from national legislations have been highlighted, and solution proposals have been put forward
Cannabinoid Receptor Ligands Modulate Fibrosis and Inflammation in Idiopathic Pulmonary Fibrosis: a Preliminary Study
No full textBackground/aim: No specific pharmacological treatment regimen for idiopathic pulmonary fibrosis (IPF) exists. Therefore, new antiinflammatory therapeutic strategies are needed. Cannabinoids (CBs), known for their inflammation-modulating and antifibrotic effects, may be potential medication candidates for treating IPF. We aim to evaluate the inflammation-modulating and antifibrotic effects of CB receptor (CBR) agonists and antagonists in lipopolysaccharide-stimulated normal human lung fibroblast, epithelial cells, IPF fibroblast cells, and monocytes. Materials and methods: We detected CBRs in normal human lung fibroblasts (LL24) and IPF fibroblast cells (LL29), epithelial cells (A549) and monocytes (THP-1) by flow cytometry. We determined TGF-(31, IL-8, and TNF-alpha inflammatory cytokines in the LL24, LL29, A549, and THP-1 cell culture supernatants on days 1 and 5 by ELISA. We evaluated the cell viability in LL24, LL29, and A549 cells on days 1, 3, and 5 spectrophotometrically and detected collagen Type I (ColI) production in the LL24 and LL29 cell culture supernatants on days 1, 3, and 5 by ELISA. Results: LL24, LL29, A549, and THP-1 cells exhibited CB1 (CB1R) and CB2 (CB2R) receptors. CB1R and CB2R agonists WIN55,2122 and JWH015 inhibited fibroblastic and epithelial cell proliferation on day 5. TGF-(31 and TNF-alpha release increased, while IL-8 release decreased in LL24, LL29, A549, and THP-1 cells in response to the administration of WIN55,212-2 and JWH015 at a 10-2 mM concentration. CB1R and CB2R antagonists AM251 and AM630 did not block agonistic responses, suggesting a nonclassical CBRmediated pathway. CB2R agonist JWH015 decreased ColI expression in IPF lung fibroblasts LL29 on day 3. Conclusion: These results suggest that CB signaling regulates the progression of pulmonary inflammation and fibrosis via CBR activation. This may offer a potential pharmacological tool for developing antifibrosis therapies.Scientific Research Coordination Unit of Atimath;limath;m University [ATU-ADP-2021-04]This work was supported by the Scientific Research Coordination Unit of Atilim University (#ATU-ADP-2021-04) . All authors declare that they participated in the study's design, execution, and analysis and that they approved the final version of the paper. Additionally, there are no conflicts of interest in connection with this study, and the material described within is not currently being published or under consideration for publication elsewhere.Science Citation Index Expande
The Rise of Artificial Intelligence in Vascular Surgery: a Bibliometric Analysis (2020-2024)
No full textAim: This study aims to perform a comprehensive bibliometric analysis of academic publications on AI applications in vascular surgery, identifying key authors, influential journals, prevalent research themes, and international collaborations, focusing on infrastructure, conceptual structure, and social networks within the field.Material and Methods: The analysis covers 815 documents published from 2020 to 2024, retrieved from the Web of Science Core Collection database. Metrics analyzed include publication growth, citation rates, key contributors, leading journals, prevalent themes, and international collaborations.Results: The research output showed a 15% annual growth rate, peaking in 2023. Despite increasing publications, the average citation rate per article declined. The study identified 5039 contributors with significant international co-authorship. Leading authors included Lareyre F and Raffort J, and the \"Journal of Vascular Surgery\" was the most influential journal. The USA and China led in contributions, reflecting robust research infrastructure. Key themes include risk assessment, diagnostic methods, and patient management, highlighting AI's role in enhancing diagnostic accuracy, treatment planning, and patient outcomes in vascular surgery.Conclusion: The analysis highlights the rapid growth and collaborative nature of AI research in vascular surgery. Key contributors, influential journals, and emerging themes were identified, emphasizing AI's role in improving diagnostics and patient outcomes. Limitations include the focus on one database and a five-year period, suggesting future research should include more databases and a longer timeframe. Exploring high-impact studies and practical applications will further advance the field
Determinants of R&D Expenditures in Türkiye (2003-2021)
No full textAraştırma ve Geliştirme (Ar-Ge) harcamaları, yenilik, verimlilik ve rekabetin artırılmasında kritik bir itici güç olup, makroekonomik koşullar da dahil olmak üzere çeşitli faktörlerden etkilenmektedir. Döviz kuru ve faiz oranı, sermaye maliyetini, finansmanın erişilebilirliğini ve yenilik için teşvikleri etkileyerek Ar-Ge yatırımları üzerinde önemli etkiye sahip temel makroekonomik değişkenlerdir. Bu çalışmada, Türkiye'de Ar-Ge'yi etkileyen makroekonomik faktörleri belirlemek amacıyla 2003- 2021 dönemi çeyrek yıllık verileri kullanılarak regresyon analizi yapılmıştır. Çalışmada, bağımlı değişken olarak toplam Ar-Ge harcamaları, bağımsız değişkenler olarak ise nominal döviz kuru (USD/TRY), reel GSYİH, ağırlıklı piyasa faiz oranı, patent faydalı model sayısı ve tam zaman eşdeğer Ar-Ge personeli kullanılmıştır. Elde edilen bulgular, Ar-Ge harcamaları üzerinde en belirleyici etmenlerin reel Gayrisafi Yurtiçi Hasıla ve patent/faydalı model sayısı olduğunu ortaya koymuştur. Ekonomik büyüme arttıkça, özel sektörün Ar-Ge yatırımlarını artırmaktadır. Ayrıca Ar-Ge personel sayısındaki artışın Ar-Ge harcamalarını pozitif yönde etkilemesi de saptanan bulgular arasındadır. Çalışmanın devamında yapılan doğrusal olmayan analiz sonuçlarına göre, dolar kurunun düştüğü dönemlerde patent sayısındaki artışlar daha yüksek oranlı Ar-Ge harcamalarına yol açmaktadır. Bulgular ışığında, Türkiye'de ArGe'yi artırmak için döviz kuru istikrarının yanı sıra ekonomik büyüme ve nitelikli insan kaynağına yapılan yatırımın önemi vurgulanmaktadır. Bu çalışma, Ar-Ge politikaları için önemli çıkarımlar sunmaktadır.Research and Development (R&D) expenditures are a critical driving force in enhancing innovation, productivity, and competitiveness and are influenced by various factors, including macroeconomic conditions. Exchange rates and interest rates are fundamental macroeconomic variables that significantly impact R&D investments by affecting capital costs, the accessibility of financing, and incentives for innovation. In this study, regression analysis was conducted using quarterly data from the period 2003-2021 to determine the macroeconomic factors influencing R&D in Turkey. The study used total R&D expenditures as the dependent variable, and the nominal exchange rate (USD/TRY), real GDP, weighted market interest rate, number of patent utility models, and full-time equivalent R&D personnel as independent variables. The findings revealed that the most decisive factors affecting R&D expenditures are real Gross Domestic Product and the number of patents/utility models. As economic growth increases, the private sector boosts its R&D investments. Additionally, an increase in the number of R&D personnel positively influences R&D expenditures. According to the nonlinear analysis results conducted in the latter part of the study, during periods of falling dollar exchange rates, increases in the number of patents lead to higher rates of R&D expenditures. In light of the findings, the importance of exchange rate stability, economic growth, and investment in qualified human resources for increasing R&D in Turkey is emphasized. This study offers significant implications for R&D policies
From Desperation To Best Practice: Spatial Decision-Making in the Regeneration of Gyldenrisparken
No full textPost-war social housing estates in Europe have been undergoing wide-scale regeneration to improve the physical decay of these sites and address the concentration of vulnerable residents in these areas, which has resulted in their social segregation, marginalisation and stigmatisation. As these estates cover and affect quite large public spaces, holistic approaches have recently been adopted. Bearing in mind that each regeneration case is unique, this paper describes the collaborative approach taken in the regeneration of Gyldenrisparken in Denmark, which evolved from a desperate situation to a best practice case. The paper focuses on the spatial decision-making process — in particular, how the architectural quality of physical interventions was established and how participatory mechanisms were utilised and developed to enable liveable spaces and sustainable regeneration. Making use of a combination of qualitative documentary analysis and in-depth interviews with key actors, this study encompasses the whole regeneration process, including initiatives taken by the housing association and municipal agents, the methodology developed to collect ideas and implement them in the physical design of the public spaces, and the social effort to make the whole process sustainable and the estates liveable. It concludes that post-war estates have the potential to secure their future by embracing physical and social efforts through proactive empowerment strategies and creating new spatial identities. © 2024, Henry Stewart Publications. All rights reserved.housing association Lejerbo; Danish National Building Fund Landsbyggefonden; Louisville Bar Foundation, LB
Effects of Quenching and Aging Conditions on the Hardening Behavior of 2024 Al Alloy
Get PDFAA2024 alüminyum alaşımı, düşük yoğunluğu, yüksek mukavemeti, yüksek şekillendirilebilirliği ve iyi yorulma direnci sayesinde uzay ve havacılık endüstrisinde yaygın olarak kullanılan bir yaşlandırma sertleşmesi alaşımdır. Yaşlandırma sertleşmesi, çözelti haline getirme, suverme ve yaşlandırma adımlarından oluşan üç aşamalı bir süreçtir. Bu projede, suverme ve yaşlandırma koşullarının 2024 Al alaşımının doğal yaşlanma sertleşmesi davranışı üzerindeki etkilerinin incelenmesi amaçlanmıştır. Su verme ortamı (saf su, ayçiçek yağı, tuz, şeker, metanol ve glikolün sulu çözeltileri) ve su verme sıcaklığı (-30°C, 0°C, 20°C ve 85°C) değiştirilerek çeşitli suverme koşulları oluşturulmuştur. Yukarı suverme (ani ısıtıp soğutma) deneyleri, oda sıcaklığında yaşlandırılan 2024 Al alaşımı numunelerin çok kısa süreyle (20-60 s) yüksek sıcaklığa (170°C) maruz bırakılmalarıyla gerçekleştirilmiştir. Saf ve tuzlu su dışında kalan suverme ortamlarının, zayıf ısı transfer kabiliyetleri nedeniyle 2024 Al alaşımının suverme sırasında sertleşmesini engelleyemediği ve bunun da suverilmiş halde yüksek sertlik değerlerine yol açtığı tespit edilmiştir. Yukarı suverme deneylerinin sonuçları bu yöntemin 2024 Al alaşımının hızlandırılmış sertleşmesi için çok etkili olduğunu göstermiştir. Katı çözelti içinde alaşım elementleri bakımından zengin kümelerin oluşumunun yukarı su verilmiş numunelerin sertliklerinde gözlemlenen artışın ardındaki ana mekanizma olduğu düşünülmektedir.AA2024 aluminum is an age hardening alloy which is widely used in aerospace industry thanks to its low density, high strength, high formability and good fatigue resistance. Age hardening is a three-step process which consists of solutionizing, quenching and aging steps. This project aimed at studying the effects of quenching and aging conditions on the natural age hardening behavior of 2024 Al alloy. Various quenching conditions were created by changing the quenching medium (pure water, sunflower oil, aqueous solutions of salt, sugar, methanol, and glycol) and quenching temperature (-30°C, 0°C, 20°C and 80°C). Up-quenching experiments were performed by subjecting 2024 Al alloy samples to very short (20-60 s) thermal spikes (170°C) while they were aging at room temperature. It is found that other than pure and salty water the remaining quenching media could not prevent the hardening of 2024 Al during quenching due to their poor heat transfer capabilities and this resulted in high as-quenched hardness values. The results of the up-quenching experiments showed that it is a very effective method for the accelerated hardening of 2024 Al alloy. Formation of solute rich clusters is thought to be the main mechanism behind the observed increase in up-quenched samples
Real Options Valuation of Solar Energy Projects: a Systematic Review
No full textEnergy plays an essential role in the development of countries, addressing the basic needs of people, and advancing technological progress. As the world's population and the energy demand in the industrial sector increase rapidly, the limited non-renewable energy resources prove insufficient to supply this demand. Consequently, both developed and developing countries are shifting towards renewable energy sources to meet their energy needs. As a result, the number of renewable energy projects in the world has been increasing day by day. Solar energy technology stands as an exemplar within the realm of renewable energy resources, playing a pivotal role in contributing to their overall share. Assessing the economic feasibility of solar energy projects is crucial to ensure their success. Traditional economic analysis methods often disregard managerial flexibility, leading to prefer the real options valuation for analysing the economic feasibility of solar energy projects. Therefore, the objective of this research is to review the application of the real options valuation for valuing solar energy projects in the existing literature. The findings of this study may provide a roadmap for future research efforts. © Association of Researchers in Construction Managemen
The Impact of Metaverse Technologies on Temporomandibular Joint Education in Dentistry
Get PDFTemporomandibular Eklem (TME), konuşma ve çiğneme aktiviteleri için hayati önem taşıyan, ağız ve diş hastalıklarının tedavisinde önemli olan karmaşık bir yapıdır. Radyologlar, diş hekimleri ve ortodontistler TME ile ilgileniyor. Ancak karmaşık yapısı nedeniyle diş hekimlerinin hastaların TME davranışlarını görselleştirmesi ve anlaması zor olabilir. Eklem diski, mandibular ve temporal eklem kemikleri arasındaki menteşelenme ve kayma hareketlerini kolaylaştıran TME'nin önemli bir bileşenidir. Karmaşık anatomik bileşenler ve ilgili ilişkiler nedeniyle TME sorunlarının teşhis edilmesi zordur. TME yapılarının ve hareketlerinin görselleştirilmesi, bunları öğrenirken zorlayıcı olabilir. Diş hekimliği öğrencilerine etkili bir öğrenme deneyimi sağlamada geleneksel diş hekimliği eğitim yöntemlerinin yeterli olamayabileceği görülmektedir. Bu tezde, insan TME'sinin anatomik yapılarını 3 boyutlu sanal ortamda simüle eden bir öğretim sistemi oluşturarak bu konuyu ele almayı amaçlayan bir çalışmadır. Bu çalışmada simülasyonlar, TME'nin karmaşıklıklarının anlaşılmasını potansiyel olarak kolaylaştırabilecek bir metavers kullanıcı arayüzüne sahip VR gözlükleri aracılığıyla sunulmaktadır. Bu çalışmada TME davranışlarını simüle etmek için insan vücudu bileşenleri kullanılarak sanal bir model geliştirilmiştir. Çalışma, amaçlanan sanal model özellikleri ve kullanıcı etkileşimleri de dahil olmak üzere, inşa edilen sistemin özelliklerini açıklamaktadır. Çalışma, sanal simülasyon modeli, diğer öğrenciler ve eğitmenlerle olan etkileşimleri de dahil olmak üzere, Metaverse tabanlı sınıftaki öğretmen ve öğrenci kullanıcılarının deneyimlerini detaylandırmaktadır. Bu çalışmada, TME kurslarına metaveri ile zenginleştirilmiş bir eğitim ortamı sağlamak için senkronize veya senkronize olmayan öğrenme modellerini kullanan ilk durumdur. Çalışmanın bulguları gelecekte sanal gerçeklik ve meta veri etkileşimlerini birleştiren sınıfların etkili bir şekilde planlanması için bir model sağlıyor. Sonuçlar, öğrencilerin TME'nin işlevlerini çeşitli bakış açıları ve açılardan deneyimlemelerine ve gözlemlemelerine olanak tanıyan, üç boyutlu sanal ortamlarda gelişmiş TME anatomik yapısı ve fonksiyonel simülasyon için metaverse teknolojilerinin geliştirilebileceği fikrini desteklemektedir. Aynı zamanda tek bir sanal sınıfta, simüle edilmiş sanal yapılar üzerinde işbirliği yapmalarına ve dünyanın dört bir yanından akranları ve profesyonellerle tartışmalar yapmalarına olanak tanır. Anahtar Kelimeler: Çene Eklemi, Metaverse, Sanal Gerçeklik, Dişçilik Eğitimi.The complex structure known as the Temporomandibular Joint (TMJ) is essential for chewing and speaking, and it also plays a significant role in the treatment of oral and dental diseases. Radiologists, dentists, and orthodontists are all interested in TMJ. However, due to its complex structure and habits, it can be challenging for dentists to visualize and understand patients' TMJ behaviours. The articular disc is a crucial component of the TMJ that facilitates hinging and gliding movements between the mandibular and temporal articular bones. TMJ issues are difficult to diagnose due to the intricate anatomical components and relationships involved. The visualization of the TMJ structures and their movements can be challenging when learning them. It seems that the traditional dental education methods may not be sufficient in providing an effective learning experience for dental students. This is a study that aims to address this issue by creating an instructional system that simulates the anatomic structures of the human TMJ in a 3D virtual environment. The simulations are presented in this work through virtual reality (VR) glasses with a metaverse user interface, which could potentially make it easier to understand the complexities of the TMJ. A virtual model is developed to simulate TMJ behaviours in this study, using virtual human body components. The study describes the specifics of the built system, including the intended virtual model features and user interactions. The study details the experiences of teacher and student users in the Metaverse-based classroom, including their interactions with the virtual simulation model, other students, and instructors. This study is the first case to use synchronized or asynchronized learning models to provide TMJ courses with a metaverse-enriched educational environment. The findings of the study provide a model for effectively planning classrooms incorporating virtual reality and metaverse interactions in the future. The findings lend credence to the hypothesis that metaverse technologies may be created for better TMJ functional modelling and anatomical structure in three-dimensional virtual spaces, enabling students to experience and see the TMJ's activities from a variety of perspectives. It also enables them to collaborate on simulated virtual structures and have discussions with peers and professionals from around the world, all in a single virtual classroom. Keywords: Temporomandibular Joint, Metaverse, Virtual Reality, Dental Educatio