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Role of Gas Flow Direction on Monolayer Mos2 Growth on Patterned Surfaces Via Cvd
No full textThe chemical vapor deposition (CVD) technique has been widely used to grow high quality single layer MoS2 crystals. However, there are still issues that need to be clarified in order to determine the appropriate conditions for the repeatable and scalable process. In this study, we experimentally investigated the effect of flow direction on the size distribution and optical signal of monolayer MoS2 flakes grown on microchannel arrayed surfaces. As an important parameter controlling the CVD process, the carrier gas flow was revealed to be highly sensitive to geometric orientation of the patterned surface. The flow direction parallel to the array yielded larger flakes with narrower size distribution, and enhanced photoluminescence (PL) peak intensities compared to the case with flow normal to the array while the Raman intensities for both the cases are almost the same. The size distributions were obtained as 6 +/- 13 and 37 +/- 4 mu m for the perpendicular and parallel cases, respectively. It was also found that the PL peak intensity increased by approximately 1.5 times when switching to parallel configuration. This study presents an experimental approach to understand the influence of the precursor stream reshaped by the growth surface geometry on the structural and optical properties of monolayer MoS2, which has great potential for use in optoelectronic applications.Scientific and Technological Research Council of Turkey [TUEBITAK 121M601, TUEBITAK 118C524]This work was supported by Scientific and Technological Research Council of Turkey. Project Nos. TUEBITAK 121M601 and TUEBITAK 118C524. F G A and A Y sincerely thank Prof Dr Nihan Kosku Perkgoez and Prof Dr Feridun Ay for their valuable supports
Clinical Signs and Genetic Evaluation of Patients With Neurofibromatosis Type 1 With and Without Optic Pathway Gliomas in a Center in Turkey
No full textArticle; Early AccessPurposeOpticpathway gliomas (OPGs) occur in 15% of patients with neurofibromatosis type 1 (NF1). Their location renders biopsy or surgical resection difficult because of the risk of vision loss. Therefore, only a few NF1-OPGs have been used for tissue diagnosis, and only a few analyses have been published on the molecular changes that drive tumorigenesis.MethodsDue to this reason, we evaluated 305 NF1 patients, 34 with OPG and 271 without OPG for germ line mutations. All subjects underwent clinical examination and DNA analysis of NF1, confirming the diagnosis of NF1.ResultsClinically, the group with OPG had a significantly higher incidence of bone dysplasia (P 0.001) and more cafe-au-lait spots (P = 0.001) compared to those in the group without OPG. The frequency of Lisch nodules was on the borderline of statistical significance (P = 0.058), whereas the frequency of neurofibromas did not differ significantly (cutaneous, P = 0.64; plexiform, P = 0.44). Individuals with OPG mostly had mutations in the first one-third of the NF1 gene compared with that in patients who did not have OPG. Some identical mutations were detected in unrelated families with NF1-OPG.ConclusionThe observation of certain phenotypic features and the correlation between genotype and phenotype might help to determine the risk of developing OPG with NF1.Hacettepe University Scientific Research and Development Office [H.U.BAB. 010 T02 102]This study was supported by the Hacettepe University Scientific Research and Development Office (project numbers: H.U.BAB. 010 T02 102)
The Utility of Docking Programs for the Characterization of Peptide Protein Interactions
No full textThe 3rd BEYOND 2023: Computational Science, Mathematical Modeling and Engineering Conference TOBB University of Economics and Technology, Ankara-Turkey, 19-20 October 2023Characterized by headache, fever, dyspnea, and even acute respiration distress syndrome and multiple organ failure, COVID-19 is a disease caused by SARS-CoV-2. This virus enters the host cell via its Spike Glycoprotein, interacting with host cell transmembrane protein ACE2 (angiotensin II converting enzyme). Therefore, to develop drugs against this disease, Spike Glycoprotein of SARS-CoV-2 and its specific interactions with ACE2 has a great importance. Due to their unique specialties such as being flexible, biocompatible, and target-specific, peptides are perfect candidate for rational drug design. Therefore, peptide-based drug design against COVID-19 by targeting to block Spike-ACE2 interaction is thought to be one of the best strategies on preventing the entry of the virus. Here we studied the efficacy of various molecular docking programs (i. e., Autodock Vina, HADDOCK, HPEPDOCK etc.) in terms of their ability to identify the binding site, binding conformation, and binding affinity. To this end, we conducted two benchmarking studies to dock known small molecules and peptides onto proteins. In the first one, we chose neuraminidase protein as the receptor protein and commercial drugs such as Oseltamivir, Laninamivir, Zanamivir and Peramivir as ligands. These drugs are used against H1N1 influenza virus, and their binding characteristics are well studied. In the second one, we use the same set of programs to dock peptides onto Spike Glycoprotein. These peptides have been obtained from ACE2 protein, which takes place in the SpikeACE2 interaction site. Here, we discuss the results of the benchmarking studies and the efficacy of molecular docking programs for further design of peptide-based drugs against COVID-19
Structural Optimization with Surrogate-Based Optimization Method for an Aircraft Win
No full text3rd International Congress on Multidisciplinary Natural Sciences (ICOMNAS-2023) / 3. Uluslararası Multidisipliner Doğa Bilimleri ve Mühendislik Kongresi - 2023In today’s world, simulation technology has high reliability which takes plenty of time. Due to the restricted schedule of the study, extended simulation time is always a problem. Surrogatebased optimization (SBO) improves a meta-model for an optimization process. It approximates objective and constraint functions by allocating diverse designs of experiment points. The methods of optimization have been developed to yield the best results in the last two decades. To have the best option, the meta-model is improved with an adequate number of design of experiment samples. A surrogate model helps to obtain a mathematical model of simulations. As a numerical form of analysis, the meta-model is a practical way to optimize structural parts. SBO is an efficient way to optimize several simulation data, such as the results of computational fluid dynamics (CFD) simulations for complex engineering problems. This study extends a 2D-validated CFD setup to a 3D wing model, ensuring the use of a realistic structural model. Then, it effectively validates the optimization algorithms through a Speed Reducer test case. The research employs SBO in conjunction with a parametrized finite element model (FEM) by focusing on mass optimization while considering constraints of frequency and compliance. An optimum is achieved in about 36 iterations with results suggesting promising outcomes, although the results are not definitive best candidates. The optimization method's validity is further supported by comparison with established optimization methods by highlighting its potential in structural optimization.This research is supported by TOBB University of Economics and Technology, and Turkish Aerospace Industries
The Effect of Hydrochlorothiazide on the Recurrence of Nonmelanoma Skin Cancer: a 7-Year Retrospective Study Comprising 300 Patients
No full textBackground/aim: Hydrochlorothiazide (HCTZ) possesses well-described photosensitizing properties, and a causal association with nonmelanoma skin cancer (NMSC) was recently shown. However, previous studies have not shown whether HCTZ use is associated with the risk of recurrence of basal cell carcinoma (BCC) or squamous cell carcinoma (SCC). This study aims to investigate the association between HCTZ use and recurrence in patients with NMSC.Materials and methods: We identified cases with NMSC from our hospital archives during the period between 2013 and 2019. Patients were divided into groups according to the pathological diagnosis, HCTZ use, and recurrence. Multivariable analysis was performed to determine factors associated with recurrence in BCC and SCC.Results: Recurrences of BCC were significantly higher in HCTZ users with ORs of 4.839221 (95% confidence interval [CI], 1.22-19.12). In HCTZ users, NMSC cases were associated with increased age (p 0.001 for both BCC and SCC). BCC recurrences were statistically significant with age, longer follow-up, and positive margins after excision in HCTZ users (p = 0.048, 0.020, and, 0.003, respectively). SCC recurrences were not significantly associated with HCTZ use. Conclusion: HCTZ use is significantly associated with BCC recurrences. Especially in the elderly population, cases with a positive margin should be followed closely
A Mathematical Interpretation for Outbreaks of Bacterial Meningitis Under the Effect of Time-Dependent Transmission Parameters
No full textWe consider a SIR-type compartmental model divided into two age classes to explain the seasonal exacerbations of bacterial meningitis, especially among children outside of the meningitis belt. We describe the seasonal forcing through time-dependent transmission parameters that may represent the outbreak of the meningitis cases after the annual pilgrimage period (Hajj) or uncontrolled inflows of irregular immigrants. We present and analyse a mathematical model with time-dependent transmission. We consider not only periodic functions in the analysis but also general non-periodic transmission processes. We show that the long-time average values of transmission functions can be used as a stability marker of the equilibrium. Furthermore, we interpret the basic reproduction number in case of time-dependent transmission functions. Numerical simulations support and help visualize the theoretical results.Scientific and Technological Research Council of Turkey (TUBITAK) - 1001-Scientific and Technological Research Project [119F162]This research is supported by The Scientific and Technological Research Council of Turkey (TUBITAK) within the scope of the 1001-Scientific and Technological Research Project (119F162)
Jj-Soma: Towards a Spiking Neuromorphic Processor Architecture
No full textNeuromorphic computing and artificial neurons have been shown to improve the solution for some of the complex problems for conventional computers. We present a spiking soma (JJ-Soma) circuit that consists of a double-junction SQUID interfered with a resistor (threshold loop), a decaying superconductor loop cut by a resistor, which is coupled to the SQUID like structure. The proposed soma has three main properties: (i) ultra-high-speed operation with minimal power consumption, (ii) compatibility with standard foundry processes that allows fabrication with the available infrastructure, (iii)and compatibility with conventional SFQ logic gates which enables design and implementation of complicated networks. Each soma circuit covers 40 ;#x03BC;m ;#x00D7; 80 ;#x03BC;m area on-chip with different activation functions. The circuits are fabricated in a commercial foundry for superconductors and they have been implemented and demonstrated experimentally. IEE
Bir Kimlik Olarak Türkçe Sözlü Müziğin Ekonomi-politik Evrimi: İçerisi/dışarısı
No full text[No Abstract Available
Deconstructing Japan's Foreign and Security Policy Transformation: Patterns of Change and Continuity
No full textYöntem olarak söylem analizi kullanan bu tez; Soğuk Savaş döneminin sona ermesinden bu yana Japonya'nın savunma stratejisinde belirgin bir değişim görüldüğü varsayımına dayanarak, Japonya'nın dış ve güvenlik politikalarının dönüşümünü açıklamaktadır. Japonya'yı çevreleyen uluslararası güvenlik ortamının tahribata uğraması sebebi ile, Japonya hükümeti kurallara dayalı uluslararası düzenin sürdürülmesi için Japonya'nın askeri gücünü arttırmış ve Özgür ve Açık Hint-Pasifik'i (FOIP) oluşturmuştur. Bu tez ilk olarak, birincil kaynakların ve siyasi figürlerin politik söylemlerini inceleyerek, Japonya'nın güvenlik reformlarını agresif güçlerden kaynaklanan güvenlik tehditlerinin artmasına yanıt olarak ele almakta ve bu durumun en iyi Tehdit Dengesi teorisi ile açıklandığını göstermeyi hedeflemektedir. Diğer bir yandan, Japonya'nın savunma postürünün Realizm ile açıklanabilecek yönleri olmasına karşın, Özgür ve Açık Hint-Pasifik'in norm-temelli ve kapsayıcı faktörlerini ele almada yetersiz kaldığını göstermektedir. Bu doğrultuda; ikinci olarak, Özgür ve Açık Hint-Pasifik'in İnşacılık teorisinin temelinde yer alan Güvenlik Topluluğu ile uyum içerisinde olduğunu göstermeyi amaç edinmiştir. Son olarak bu tez, Japonya'nın dış ve güvenlik politika temelinde var olan değişimi kademeli olarak nitelendirerek, Japonya'nın dış ve güvenlik politika söyleminde yer edinmiş olan sürekliliği ortaya çıkarmayı hedeflemektedir.Based on the presumption that Japan's defense strategy has changed considerably since the end of the Cold War, this thesis explains Japan's rationale for the transformation of its foreign and security policies by using discourse analysis as its method. Due to the deterioration of the security environment surrounding Japan, the Japanese government has improved Japan's military capabilities and formed the Free and Open Indo-Pacific (FOIP) to maintain the rules-based international order. Through the investigation of primary documents and policy statements of political figures, firstly, the thesis aims to show that Japan has made security reforms in response to growing security threats emanating from aggressive powers, which can be best understood with the Balance of Threat theory. On the other hand, while certain aspects of Japan's defense posture can be understood within the framework of Realism, there are also norm-based, inclusive elements in Japan's FOIP that Realist theory falls short of explaining. To that end, secondly, the thesis aims to reveal that the FOIP is inherently consistent with the concept of Security Community as a premise of Constructivism. In the end, through identifying the change in Japan's foreign and security policy as gradual, the thesis aims to demonstrate the consistency rooted in Japan's foreign and security policy discourse