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New black hole solutions of second and first order formulations of nonlinear electrodynamics
No full textInspired by the so-called Palatini formulation of general relativity and of its modifications and extensions, we consider an analogous formulation of the dynamics of a self-interacting gauge field which is determined by nonlinear extension of Maxwell's theory, usually known as nonlinear electrodynamics. In this first order formalism the field strength and the gauge potential are treated, a priori as independent, and, as such, varied independently in order to produce the field equations. Accordingly we consider within this formalism alternative and generalized nonlinear Lagrangian densities, some of them of a new kind which gives up the restriction of equivalence to second order Lagrangians. Several new spherically symmetric objects are constructed analytically and their main properties are studied. The solutions are obtained in flat spacetime ignoring gravity and for the self-gravitating case with emphasis on black holes. As a background for comparison between the first and second order formalisms, some of the solutions are obtained by the conventional second order formalism, while for others a first order formalism is applied. Among the self-gravitating solutions we find new families of black holes and study their main characteristics. Some of the flat space solutions can regularize the total energy of a point charge and a subset of them exhibit also finite field strength and energy density, although their black hole counterparts are not regular
A guide for blood-brain barrier models
No full textUnderstanding the intricate mechanisms underlying brain-related diseases hinges on unraveling the pivotal role of the blood–brain barrier (BBB), an essential dynamic interface crucial for maintaining brain equilibrium. This review offers a comprehensive analysis of BBB physiology, delving into its cellular and molecular components while exploring a wide range of in vivo and in vitro BBB models. Notably, recent advancements in 3D cell culture techniques are explicitly discussed, as they have significantly improved the fidelity of BBB modeling by enabling the replication of physiologically relevant environments under flow conditions. Special attention is given to the cellular aspects of in vitro BBB models, alongside discussions on advances in stem cell technologies, providing valuable insights into generating robust cellular systems for BBB modeling. The diverse array of cell types used in BBB modeling, depending on their sources, is meticulously examined in this comprehensive review, scrutinizing their respective derivation protocols and implications. By synthesizing diverse approaches, this review sheds light on the improvements of BBB models to capture physiological conditions, aiding in understanding BBB interactions in health and disease conditions to foster clinical developments
A sustainable solution for the hospitality industry: the QR code menus
No full textThis case presents a study of how QR code menus have emerged as a popular and sustainable solution for the hospitality industry in the wake of the COVID-19 pandemic. The case explores the environmental benefits of QR code menus in the restaurant industry by drawing on existing literature and examining how QR code menus can reduce paper waste, lower carbon footprint, and promote sustainable practices. The case also discusses how QR code menus contribute to several United Nations Sustainable Development Goals (SDGs), such as SDG 12 (Responsible Consumption and Production), SDG 13 (Climate Action), and SDG 17 (Partnerships for the Goals). The case concludes that QR code menus offer various benefits for restaurants and customers, such as reducing waste, enhancing customer experience, supporting local and organic food producers, and promoting responsible consumption and production. The case also suggests that QR code menus are not only a digital transformation tool but also a step towards creating a more eco-friendly and resilient restaurant industry
Lead treatment affects mineral element status in rye (Secale cereale L.) plants
No full textLead (Pb) is among the most toxic heavy metals in biological systems and causes toxicity from seed germination to yield formation. High Pb concentrations lead to oxidative damage and impair water relation and nutrition uptake in plants. Rye (Secale cereale L.) is an abiotic stress-tolerant crop, distributed in Eastern and Central Europe. Pb concentration in soils higher than 30 mg kg−1 is commonly toxic to plants. This study investigated the effects of different Pb concentrations [0, 100, 200 and 400 μM of Pb(NO3)2] on mineral element concentrations (B, Ca, Cu, Fe, K, Mg, Mn, Na and Zn) in rye plants. After 15 days of Pb stress, the levels of mineral elements (B, Ca, Cu, Fe, K, Mg, Zn, Mn and Na), and Pb accumulation were detected using by ICP-OES (Inductively coupled plasma-optical emission spectrometry) in leaves and roots. Under 0, 100, 200 and 400 μM Pb application, the Pb accumulation varied between 0.005–2.94 and 5.63–13.63 mg kg−1 in leaves, and 0.03–69.34–168.11–329.74 mg kg−1 in roots, respectively. Roots accumulated higher levels of Pb than the leaves. The amounts of Na, Fe and B concentrations reduced, whereas the contents of Ca, K, Mn, Cu, and Zn increased in both leaves and roots in a concentration-dependent manner. The maximum rate of increase or decrease in elemental contents was recorded for 400 μM Pb-exposed plants. In addition, Mg content increased in leaves, but decreased in roots. Overall, our findings suggest that Pb-exposure causes alterations in mineral element concentrations in a concentration-dependent manner, which could be useful to make risk assessments for Pb pollution in agricultural lands
Animal Rights And The Ethics Of Multispecies Co-Living: Everyday Life Of A Vegan Farm
Full text linkThis thesis examines multispecies co-living at a vegan farm established in İzmir,Turkey. It explores this locally rooted initiative’s potential for reimagining a nonspeciesistway of living while investigating how a rights-based approach is enactedin practice. It reads the formation of interspecies relations through an ethnographiclens embedded in everyday life and attuned to sensory experiences. Drawing onveganism and animal rights, it builds the theoretical framework to explore therights-based motivations underpinning such an initiative. Focusing primarily oninteractions between chickens and humans but also considering the relations betweenmany other species living on the farm, the thesis highlights the significance ofsensory engagement in ethically informed, care-based relationships. By examiningthese interactions through everyday routines, it considers how non-speciesist knowledgeproduction and dissemination occur. Rather than portraying the farm as aplace without challenges or conflicts, the study attends to the complex realities ofco-living—including illness, death, and conflict—arguing that such experiences areintegral to building interspecies communities. It further contends that these spacesfunction as sites of knowledge-making, community-building, and resistance—bothmaterially and politically—against systemic animal exploitation, while also providingpractical insight into how ethical multispecies cohabitation can be implementedin everyday life
In The Realm Of Heat And Water: Social Lives And Materiality Around Infrastructural
Full text linkBeginning with the contextualization of a local activity in Adana, namely bathing inthe irrigation canals, this thesis has expanded to investigate social relationships andmateriality around the infrastructural environment in the domain of heat and waterin urban Adana. Tracing agricultural infrastructure’s interventions in topographies,this thesis aims first to locate the conditions that make modern Çukurova(the “fertile lands” in commonsense), then unfolds discussions about nature andcity by positing infrastructural production of the urban environment. Adopting amateriality-based approach, this thesis proposes a study of infrastructures that doesnot focus on technical design and function, but on undesigned prolific engagements.Suggesting an infrastructural environment and emphasizing such an urban topography,it notes, on the one hand, both transgressive and tailored acts (e.g., canalbathingand care work) by focusing on the materiality of forms and relationships;on the other, presents how social lives and materiality around the water environmenthave both affect-laden and gendered facets. This thesis aims to point out theenvironmental justice aspect of heat and water in an urban area and to mark theundesigned relationships with infrastructures
Modulation Of Glioblastoma Cell Behavior By Monocyte-Derived Macrophages And Frequency-Dependent Attraction On A Microfluidıc Chip
Full text linkGlioblastoma Multiforme (GBM) is a highly aggressive and heterogeneous primarybrain tumor, marked by rapid proliferation, therapeutic resistance, and complexinteractions within the tumor microenvironment (TME). Among the key modulatorsof the TME are tumor-associated macrophages (TAMs), which play a pivotalrole in shaping glioma behavior and influencing treatment outcomes. This thesisinvestigates the impact of monocyte-derived macrophage phenotypes (M0, M1, andM2) on glioma cell proliferation and migration. THP-1 cells were differentiatedinto macrophage subtypes via cytokine-driven protocols. Functional assays revealedthat M1 macrophages enhanced glioma proliferation while attenuating migratorycapacity, whereas M2 macrophages initially suppressed proliferation, followed by increasedgrowth and significantly enhanced wound closure, suggesting a dual-phasemodulatory effect.To enable precise, label-free cellular analysis, a microfluidic platform incorporatingdielectrophoresis (DEP) was developed. Computational simulations validated optimalelectric field distributions for effective DEP-based manipulation of glioma cells.The DEP buffer was shown to preserve glioma cell viability, supporting its potentialuse in non-destructive diagnostics. Additionally, impedance spectroscopy confirmedthe system’s sensitivity to cellular heterogeneity across different glioma lines. Deviceperformance was validated using U-87 glioma cells, demonstrating reliable cell behavior tracking and morphological assessment.Overall, the study underscores the regulatory role of macrophage subtypes in GBMprogression and highlights the promise of DEP-integrated microfluidics for advancedglioma diagnostics and future therapeutic applications
An investigation into bandwith expansion and signal integrity of frequency-multiplier-last transmitters
Full text linkThe evolution of wireless communications necessitates transmitters capable of achieving data rates in the range of tens of gigabits per second. Due to high congestion and strict regulations, lower-frequency bands are unlikely to satisfy the growing data-rate demands set by regulatory bodies such as the International Telecommunication Union (ITU). Consequently, sub-THz frequencies (above 100 GHz) are being explored as viable alternatives for high-speed wireless communication.However, the relatively low maximum operating frequencies of CMOS transistors pose limitations for conventional transmitter architectures, which typically rely on power amplifiers in their final stage. To address this challenge, frequency-multiplier-last transmitters have been proposed, enabling efficient frequency upconversion to sub-THz bands using solely CMOS technology. Despite their advantages, these transmitters introduce significant distortions due to the frequency multiplier stage, negatively impacting digital communication performance.This thesis presents a mathematical system-level analysis of these impairments. The analysis demonstrates that even-order multipliers are inadequate for supporting digital IQ modulation-based communication between the transmitter and receiver. It further reveals that the signal-to-noise ratio (SNR) degrades proportionally to the square of the multiplier order. The thesis concludes that the frequency tripler is the most suitable option for digital communication in frequency-multiplier-last transmitters
Key developments in international transport research: editorial note for the Procedia volume from the 16th WCTR in Montréal
No full textThis paper serves as the editorial note for Volume 82 of the Transportation Research Procedia, featuring research papers presented at the 16th World Conference on Transport Research (WCTR) held in Montréal, Canada. The paper begins by highlighting the role of the World Conference on Transport Research Society and providing insights into the Montréal conference, including the paper review process. It then outlines the various topic areas and special interest groups, acknowledging the contributions of numerous scholars involved in the process. Finally, the paper offers a synthesis of the research topics presented in Montréal and proposes future research directions for the transportation research community
Nanomechanical systems for reservoir computing applications
Full text linkReservoir computing (RC) provides a route to use physical systems for computation and machine learning. Owing to their inherent nonlinearity, nanomechanical systems constitute an interesting technology to serve as reservoir. While RC platforms are built using microelectromechanical systems, the energy efficiency, response time, and footprint of these systems can be significantly improved by using nanoscale devices. Herein, the use of nanoelectromechanical systems (NEMS) is investigated, which can be used in RC, utilizing inherent nonlinearities and the fading memory effect from the transient response of NEMS. The smaller size and higher operating frequencies of NEMS enable faster processing rates compared to micromechanical systems, while their compact footprint, low power consumption, and ability to operate under ambient conditions simplify integration into practical applications. In modified national institute of standards and technology (MNIST) handwritten digit–recognition test, this system achieves 90% accuracy with a 3.3 μs processing time per pixel. Also the effect of driving frequency and amplitude on NEMS classification accuracy is investigated using experiments and simulations and it is shown that no significant dependency in any of the parameters is observed. Herein, an estimate for energy consumption of core NEMS RC system on MNIST data is provided. These results highlight the potential for various applications that require efficient and fast information processing in resource-constrained environments