819 research outputs found
Active multilayer mirrors for reflectance tuning at extreme ultraviolet (EUV) wavelengths
We propose an active multilayer mirror structure for EUV wavelengths
which can be adjusted to compensate for reflectance changes. The multilayer structure tunes the reflectance via an integrated piezoelectric layer that can change its dimension due to an externally applied voltage. Here, we present design and optimization of the mirror structure for maximum reflectance tuning. In addition, we present preliminary results showing that the deposition of piezoelectric thin films with the requisite layer smoothness and crystal structure are possible. Finally, polarization switching of the smoothest piezoelectric film is presented
Design of Hydroxyapatite/Magnetite (HAP/Fe3O4) Based Composites Reinforced with ZnO and MgO for Biomedical Applications
Hydroxyapatite (HAP-- Ca 10(PO4 )6 (OH)2 ) is a biocompatible and bioactive material that is widely used for biomedical applications, especially in bone replacements. It has good load carrying capacity; however, it lacks antibacterial property. New bio-composites based on bovine hydroxyapatite doped with, magnetite iron oxide (HAP/ Fe3 O4 ) matrix reinforced with ZnO and MgO nanoparticles are proposed for biomedical applications that provide improved antibacterial activity with potential to be used in magnetic therapy. Microwave sintering was used to manufacture the composites. The microstructure evolution in these composites were studied by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). Density, microhardness, compressive strength of the composites was measured and compared along with their magnetic properties. Finite element analysis simulations were performed for the compression tests
AN ESSAY ON THE MEANING TRANSFORMATIONS OF WORDS PASSED TO BULGARIAN FROM TURKISH LANGUAGE
Dil, insanoğlunun en gizemli araçlarının başında gelir. Dil, sonsuz algının, sonsuz etkileşimin zaman içinde çoklu değişimlerine sürekli maruz kaldığı halde iletişimin kesintisiz sürmesini sağlamaktadır. İnsanın güçlü-güçsüz, yöneten-yönetilen ikileminde dil de üzerine düşen görevi yapmakta; üsttekinden alttakine, yönetenden yönetilene veri sunmaktadır. Alıcı taraf aldıklarını evirir, kendileştirir öyle ki bir zaman sonra ona ait olmadığını bilmek ancak uzmanların tekelinde olur. Türkler tarih boyu Balkanlara birçok yoldan birçok kez ulaştılar. Ama en derin izlerini elbette ki Osmanlı hâkimiyeti süresinde bıraktılar. Bu izler Balkan dillerinin sözlüklerinde tanıklıklarını bu gün de sürdürmektedir. Ancak alınan her sözcük alındığı dilde başka formlarda, başka seslerde ve başka anlamlarda yaşamayı tercih etmişlerdir. Biz bu çalışmamızda Balkanlarda en çok birlikte yaşadığımız Bulgaristan'da, Bulgar diline verdiğimiz sözcüklerdeki anlam değişmeleri üzerinde duracağız. Bu çalışma Günay Karaağaç'ın "Verintiler Sözlüğü" adlı kitabındaki veriler üzerinden derlenmiştirLanguage, comes at the beginning of the most mysterious tools of mankind. Language ensures the uninterrupted continuation of the communication although it is constantly exposed to multiple transformations of the infinite perception and endless interaction over time. In the dilemma of strong-weak and administrator-the managed, the Language also plays its role; transferring information from top to bottom and from administrator to the being administered. The receiving side inverts and makes the acquired words so self-owned that, after some time, only specialists can figure out that they are not their own. Turks have reached the Balkans many times throughout history in many ways. But of course they left the deepest traces during the Ottoman domination. These traces continue witnessing in the dictionaries of Balkan Languages till today. However, every word has preferred to live in different forms, different sounds and different means than they were came from. In this study, we will focus on the changes in word meanings we gave to the Bulgarian language, which we longest co-lived among the Balkan nations. This study has been compiled based on the data in the “Verintiler Sözlüğü” (dictionary of words exported) of Günay Karaağa
How do supply chain management and information systems practices influence operational performance?:Evidence from emerging country SMEs
This study first provides a comparative analysis of the impact of supply chain management (SCM) and information systems (IS) practices on operational performance (OPER) of small- and medium-sized enterprises (SMEs) operating in two neighbouring emerging country markets of Turkey and Bulgaria. Then, we investigate moderating effects of both SCM–IS-linked enablers and inhibitors on the links between SCM and IS practices and OPER of SMEs. To this end, we first empirically identify the underlying dimensions of SCM and IS practices, and SCM–IS-related enabling and inhibiting factors. Second, a series of regression analyses are undertaken to estimate the impact of the study's constructs on OPER of SMEs. The results are discussed comparatively within the contexts of both Turkish and Bulgarian SMEs and beyond. The study makes a significant contribution to the extant literature through obtaining and analysing cross-national survey data of SCM and IS practices in emerging country markets
Esophageal cancer presenting with atrial fibrillation: A case report
<p>Abstract</p> <p>Introduction</p> <p>Atrial fibrillation was previously reported in patients with esophageal cancer as a complication of total esophagectomy or photodynamic therapy. Here, we propose that atrial fibrillation may also be caused by external compression of the left atrium by esophageal cancer.</p> <p>Case presentation</p> <p>We present a 58-year-old man who developed atrial fibrillation with rapid ventricular rate in the emergency room while being evaluated for dysphagia and weight loss. Atrial fibrillation lasted less than 12 hours and did not recur. Echocardiogram did not reveal any structural heart disease. A 10-cm, ulcerated mid-esophageal mass was seen during esophagogastroscopy. Microscopic examination showed squamous cell carcinoma. Computed tomography of the chest revealed esophageal thickening compressing the left atrium.</p> <p>Conclusion</p> <p>External compression of the left atrium was previously reported to provoke atrial fibrillation. Similarly, esophageal cancer may precipitate atrial fibrillation by mechanical compression of the left atrium or pulmonary veins, triggering ectopic beats in susceptible patients.</p
Exploring wind direction and SO2 concentration by circular-linear density estimation
The study of environmental problems usually requires the description of
variables with different nature and the assessment of relations between them.
In this work, an algorithm for flexible estimation of the joint density for a
circular-linear variable is proposed. The method is applied for exploring the
relation between wind direction and SO2 concentration in a monitoring station
close to a power plant located in Galicia (NW-Spain), in order to compare the
effectiveness of precautionary measures for pollutants reduction in two
different years.Comment: 17 pages, 7 figures, 2 table
Characterization of fault plane and coseismic slip for the 2 May 2020, M-w 6.6 Cretan Passage earthquake from tide gauge tsunami data and moment tensor solutions
We present a source solution for the tsunami generated by the M-w 6.6 earthquake that occurred on 2 May 2020, about 80 km offshore south of Crete, in the Cretan Passage, on the shallow portion of the Hellenic Arc subduction zone (HASZ). The tide gauges recorded this local tsunami on the southern coast of Crete and Kasos island. We used Crete tsunami observations to constrain the geometry and orientation of the causative fault, the rupture mechanism, and the slip amount. We first modelled an ensemble of synthetic tsunami waveforms at the tide gauge locations, produced for a range of earthquake parameter values as constrained by some of the available moment tensor solutions. We allow for both a splay and a back-thrust fault, corresponding to the two nodal planes of the moment tensor solution. We then measured the misfit between the synthetic and the Ierapetra observed marigram for each source parameter set. Our results identify the shallow, steeply dipping back-thrust fault as the one producing the lowest misfit to the tsunami data. However, a rupture on a lower angle fault, possibly a splay fault, with a sinistral component due to the oblique convergence on this segment of the HASZ, cannot be completely ruled out. This earthquake reminds us that the uncertainty regarding potential earthquake mechanisms at a specific location remains quite significant. In this case, for example, it is not possible to anticipate if the next event will be one occurring on the subduction interface, on a splay fault, or on a back-thrust, which seems the most likely for the event under investigation. This circumstance bears important consequences because back-thrust and splay faults might enhance the tsunamigenic potential with respect to the subduction interface due to their steeper dip. Then, these results are relevant for tsunami forecasting in the framework of both the long-term hazard assessment and the early warning systems
Exosomal miR-940 maintains SRC-mediated oncogenic activity in cancer cells: a possible role for exosomal disposal of tumor suppressor miRNAs
Exosomes have emerged as important mediators of diverse biological functions including tumor suppression, tumor progression, invasion, immune escape and cell-to-cell communication, through the release of molecules such as mRNAs, miRNAs, and proteins. Here, we identified differentially expressed exosomal miRNAs between normal epithelial ovarian cell line and both resistant and sensitive ovarian cancer (OC) cell lines. We found miR-940 as abundant in exosomes from SKOV3-IP1, HeyA8, and HeyA8-MDR cells. The high expression of miR-940 is associated with better survival in patients with ovarian serous cystadenocarcinoma. Ectopic expression of miR-940 inhibited proliferation, colony formation, invasion, and migration and triggered G0/G1 cell cycle arrest and apoptosis in OC cells. Overexpression of miR-940 also inhibited tumor cell growth in vivo. We showed that proto-oncogene tyrosine-protein kinase (SRC) is directly targeted by miR-940 and that miR-940 inhibited SRC expression at mRNA and protein levels. Following this inhibition, the expression of proteins downstream of SRC, such as FAK, paxillin and Akt was also reduced. Collectively, our results suggest that OC cells secrete the tumor-suppressive miR-940 into the extracellular environment via exosomes, to maintain their invasiveness and tumorigenic phenotype
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