17315 research outputs found
Sort by
In-situ functionalization of cotton fabrics with polydopamine and silver nanoparticles for multifunctional applications
No full textThis study presents a sustainable approach to enhance cotton fabrics with multifunctional properties by in-situ functionalization using polydopamine (PDA) coating followed by the deposition of silver nanoparticles (AgNPs) through a self-reduction process. Polydopamine was chosen for its excellent adhesive and reductive properties, facilitating the uniform attachment of silver nanoparticles on the fabric surface. The functionalized fabrics were thoroughly characterized using FTIR, Raman spectroscopy, SEM, EDS, TGA, contact angle measurements, and XRD, confirming the successful integration of PDA and AgNPs. The modified cotton fabrics demonstrated 100% antibacterial activity against Staphylococcus aureus and achieved a water contact angle of approximately 131°, indicating enhanced hydrophobicity. Thermal stability was also improved, with a 15% increase in ash content at 600 °C. This dual-functional coating approach provides an effective means to develop antibacterial, water-resistant, and thermally more stable textile materials, offering potential applications in protective clothing, and other functional fabric domains
Impact damage and low temperature effects on carbon fiber/epoxy joints: a comparative study of hybrid bolted/bonded and bolted configurations with cross-ply and angle-ply laminates
No full textThis study investigates the tensile and tensile after impact (TAI) performance of hybrid bolted/bonded (HBB) and only bolted (OB) carbon fiber/epoxy composite joints with cross-ply (CP) and angle-ply (AP) stacking sequences under low-temperature (LT) conditions. The focus is on the behavior of these joints under low temperatures with barely visible impact damage (BVID), relevant to aerospace and high-performance industries. In situ acoustic emission (AE) analysis and fractographic examinations synergistically evaluate the effects of LT (−55 °C) and BVID (10 J energy level) on these joints. Results indicate that HBB-CP intact joints exhibit higher load-bearing capacity at LT due to increased adhesive and matrix stiffness but demonstrate more brittle responses. The combined impact of low temperature and impact loading significantly affects impacted CP joints, leading to notable damage and reduced load-bearing capacity. Although HBB-CP joints are more susceptible to BVID than OB-CP joints, they still outperform overall. AE and fractographic analyses reveal fiber-related failures in CP laminates and matrix/interface failures in AP laminates, with increased matrix cracking at low temperatures. This research provides a comprehensive analysis of the interplay between impact dynamics, temperature variations, and stacking sequence configurations on hybrid and bolted composite joints
Ranking single fluorescent protein-based calcium biosensor performance by molecular dynamics simulations
No full textGenetically encoded fluorescent biosensors (GEFBs) have become indispensable tools for visualizing biological processes in vivo. A typical GEFB is composed of a sensory domain (SD) that undergoes a conformational change upon ligand binding or enzymatic reaction; the SD is genetically fused with a fluorescent protein (FP). The changes in the SD allosterically modulate the chromophore environment whose spectral properties are changed. Single fluorescent (FP)-based biosensors, a subclass of GEFBs, offer a simple experimental setup; they are easy to produce in living cells, structurally stable, and simple to use due to their single-wavelength operation. However, they pose a significant challenge for structure optimization, especially concerning the length and residue content of linkers between the FP and SD, which affect how well the chromophore responds to conformational change in the SD. In this work, we use all-atom molecular dynamics simulations to analyze the dynamic properties of a series of calmodulin-based calcium biosensors, all with different FP-SD interaction interfaces and varying degrees of calcium binding-dependent fluorescence change. Our results indicate that biosensor performance can be predicted based on distribution of water molecules around the chromophore and shifts in hydrogen bond occupancies between the ligand-bound and ligand-free sensor structures
Turkey's 2024 municipal elections: a turning point for democratic resilience?
No full textThe 2024 local elections in Turkey represented an important signal for the country’s changing political environment. The ruling Justice and Development Party (AKP) suffered its most severe electoral defeat since first coming to power in the 2002 general elections. Despite an uneven playing tilted in favour of the ruling alliance, the opposition led by the CHP party succeeded in a threefold feat: reasserting its political dominance in the large cities, expanding its electoral appeal to the AKP strongholds, and, most importantly, overtaking Erdoğan’s AKP at the national level for the first time. The result appears even more striking when one considers that just over a year ago, Erdoğan’s ruling alliance had won a clear victory in the presidential and parliamentary elections. Although these two elections underlie different dynamics, this article analyzes the factors that led to this dramatic reversal
Shape-controlled Bose-Einstein condensation
No full textSize-invariant shape transformation is a geometric technique that allows for a clear separation between quantum size and shape effects by modifying the shape of the confinement domain without altering its size. The impact of shape on the behavior of confined systems is significantly different from that of size, making it an emerging area of research. The recent realization of flat-bottomed optical box traps has further contributed to the study of quantum gases in complex confinement geometries. Here, we propose shape-induced Bose-Einstein condensation at a fixed size, temperature, and density. We investigate the impact of pure quantum shape effects on a non-interacting Bose gas confined within nested square domains, where the shape parameter is defined and controlled by the rotation angle between the inner and outer squares. Our findings reveal that specific heat exhibits an additional low-temperature peak at certain shapes. This work opens new avenues for controlling quantum systems through geometric manipulation and provides insights into the thermodynamic properties of Bose gases under shape-induced quantum effects
Wealth inequality in northwestern Anatolia under the Ottomans, 1460-1870
No full textWhile studies indicate that economic inequality increased in the early modern period, it is debated whether this applied to all regions, and what the causes of change were. This paper studies long-term wealth inequality in the Ottoman Empire, and its possible determinants, using data from Anatolia. Inequality tended to track demographic and economic change, but evidence for a long-term correlation is inconclusive, whereas there is evidence for the long-term disequalizing impact of taxation and changing power relations. The divergence between cities and countryside suggests structural shifts caused by external factors, and comparison with the slow economies of Europe reveals diversity within this group
Design of patient-specific mandibular reconstruction plates and a hybrid scaffold
No full textBackground: Managing segmental mandibular defects remains challenging, requiring a multidisciplinary approach despite the remarkable progress in mandibular reconstruction plates, finite element methods, computer-aided design and manufacturing techniques, and novel surgical procedures. Complex surgeries require a comprehensive approach, as using only reconstruction plates or tissue scaffolds may not be adequate for optimal results. The limitations of the treatment options should be investigated towards a patient-specific trend to provide shorter surgery time, better healing, and lower costs. Integrated hybrid scaffold systems are promising in improving mechanical properties and facilitating healing. By combining different materials and structures, hybrid scaffolds can provide enhanced support and stability to the tissue regeneration process, leading to better patient outcomes. The use of such systems represents a significant advancement in tissue engineering and a wide range of medical procedures. Materials and Methods: A head and neck computed tomography (CT) data of a patient with odontogenic myxoma was used for creating a three-dimensional (3D) mandible model. Virtual osteotomies were performed to create a segmental defect model, including the angulus mandibulae region. The first mandibular reconstruction plate was designed. Finite elemental analyses (FEA) and topology optimizations were performed to create two different reconstruction plates for different treatment scenarios. The FEA were performed for the resulting two plates to assess their biomechanical performance. To provide osteoconductive and osteoinductive properties a scaffold was designed using the defect area. A biomimetic Tricalcium phosphate-Polycaprolactone (TCP-PCL) hybrid bone scaffold enhanced with Hyaluronic acid dipping was manufactured. Results: The results of the in-silico analysis indicate that the designed reconstruction plates possess robust biomechanical performance and demonstrate remarkable stability under the most rigorous masticatory activities. Using the Voronoi pattern decreased the mass by %37 without losing endurance. Using reconstruction plates and hybrid scaffolds exhibits promising potential for clinical applications, subject to further in vivo and clinical studies
High-entropy alloys and oxides as supercapacitor electrodes: a structural and electrochemical perspective for energy storage
No full textThis study investigates the performance of high entropy alloys [Fe3Cr3Mn2NiV, HEA)] and high entropy oxides [(Fe3Cr3Mn2NiV)O4, HEO)] as electrode materials for supercapacitors. HEA is synthesized through mechanical alloying, followed by HEO forming via an oxidation process. XRD results demonstrate HEA comprises both amorphous and crystalline phases, whereas HEO has an entirely crystalline structure. SEM analyses showed HEA exhibits larger and irregular particles, whereas HEO displays a smaller and spherical morphology. EPR analyses revealed significant changes in defect structures and unpaired electron configurations during the transition from HEA to HEO. HEA is prone to diffusion-controlled processes due to their regular structure and strong magnetic interactions; however, HEO exhibits capacitive behavior based on surface redox reactions and pseudo-capacitive mechanisms due to their irregular structure and oxygen vacancies. CV analyses revealed that HEO contributes more capacitive via surface redox reactions, while GCPL results suggested that HEO demonstrated superior energy density (40.8 Wh kg−1) and power density (14.3 kW kg−1). Impedance analyses revealed that HEO exhibited reduced internal resistance and enhanced ion conductivity, whereas HEA demonstrated higher resistance and diffusion-controlled processes. In conclusion, HEA and HEO exhibit distinct energy storage mechanisms, and these materials can be optimized for supercapacitor applications
Visual search efficiency is modulated by symmetry type and texture regularity
No full textMore than a century of vision research has identified symmetry as a fundamental cue, which aids the visual system in making inferences about objects and surfaces in natural scenes. Most studies have focused on one type of symmetry, reflection, presented at a single image location. However, the visual system responds strongly to other types of symmetries and to symmetries that are repeated across the image plane to form textures. Here we use a visual search paradigm with arrays of repeating unit cells that contained either reflection or rotation symmetries but were otherwise matched. Participants were asked to report the presence of a target tile without symmetry. When unit cells tile the plane without gaps, they form regular textures. We manipulated texture regularity by introducing jittered gaps between unit cells. This paradigm lets us investigate the effect of symmetry type and texture regularity on visual search efficiency. Based on previous findings suggesting an advantage for reflection in visual processing, we hypothesized that search would be more efficient for reflection than rotation. We further hypothesized that regular textures would be processed more efficiently. We found independent effects of symmetry type and regularity on search efficiency that confirmed both hypotheses: Visual search was more efficient for textures with reflection symmetry and more efficient for regular textures. This provides additional support for the perceptual advantage of reflection in the context of visual search and provides important new evidence in favor of visual mechanisms specialized for processing symmetries in regular textures
