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Efficient detergent removal using a polydivinylbenzene adsorbent in membrane protein solubilization
No full textMembrane proteins (MPs) are essential for various cellular functions and therefore critical targets for the drug industry. However structural and functional studies of MPs are challenging due to the difficulty and cost of solubilization and purification. Effective solubilization typically requires the incorporation of MPs into detergent micelles. Despite that this is a common practice, it has the potential to destabilize MPs. Alternatively, detergent-free systems have emerged, and reconstitution of MPs in Amphipol (APol) is one of the common methods. Polystyrene beads are generally used for this purpose. We investigated and evaluated the effectiveness of polydivinylbenzene Purolite™ PuroSorb™ PAD600 beads for detergent removal in membrane protein solubilization. To accomplish this, the membrane protein FtsH, solubilized in either DDM or LMNG, was exchanged with varying concentrations of APol, and detergents were removed by Purolite™ PuroSorb™ PAD600 beads. The results demonstrate that Purolite™ PuroSorb™ PAD600 beads are effective for detergent removal when the mass ratio of the Membrane Protein:Amphipol (MP:APol) is increased up to 1:10. The usage of Purolite™ PuroSorb™ PAD600 beads supports biochemical applications for membrane protein isolation and purification studies
Power-efficient sampling: towards low-power analog-to-digital converters
No full textAnalog-to-digital converters (ADCs) facilitate the conversion of analog signals into a digital format. While the specific designs and settings of ADCs can vary depending on the application, it is crucial in many modern applications to minimize the devices’ power consumption. The significance of low-power ADCs is particularly evident in fields like mobile and handheld devices reliant on battery operation. Key parameters that dictate ADCs’ power are the sampling rate, dynamic range (DR), and number of quantization bits. Typically, these parameters are required to be higher than a threshold value but can be reduced by using the structure of the signal and by leveraging preprocessing and the system application needs. In this article, we discuss four approaches relevant to a variety of applications
Predicting workpiece dynamics in milling of thin-walled structures using three-dimensional spectral element method
No full textThis paper addresses the challenge of milling thin-walled structures, which are highly valued for their lightweight and robust characteristics yet are prone to process instabilities due to chatter-induced vibrations. These vibrations adversely affect surface quality and dimensional accuracy during material removal. Traditional finite element analysis (FEA) methods have been widely used to predict the dynamic behavior of these components; however, they often require detailed meshing and become computationally expensive when continuously updating the workpiece model. To overcome these limitations, we introduce a novel three-dimensional spectral element method (3D-SEM) based on the spectral Chebyshev approach. This method efficiently computes elemental stiffness and mass matrices and predicts the evolving frequency response functions (FRFs) at the tool–workpiece interface, which are critical for evaluating chatter stability. The performance of the proposed 3D-SEM approach is demonstrated through comparisons with FEA simulations and experimental results, showing that it delivers accurate predictions of workpiece dynamics at a significantly reduced computational cost compared to traditional FEA
Online dynamic mode decomposition based adaptive control for lane-keeping system
No full textThis study investigates the application of Online Dynamic Mode Decomposition (Online DMD) for real-time system identification and control in an autonomous vehicle lane-keeping system. The Online DMD algorithm dynamically updates a linear state-space model of lateral vehicle dynamics, enabling continuous adaptation to changing road conditions. To test the robustness and predictive capabilities of these models, Model Predictive Control (MPC) and Linear Quadratic Regulator (LQR) strategies are designed and implemented in MATLAB/Simulink. The system is evaluated under constant longitudinal velocity across diverse road sections in simulation environment. The results demonstrate that combining data-driven system identification with optimal control frameworks achieves robust lane tracking and adaptability, while also revealing that the short-term prediction capability of Online DMD may pose limitations in certain dynamic scenarios
Feasibility and performance evaluation of randomly oriented strand recycled composite skins in sandwich structures: a green cost-effective solution for aerospace secondary load-bearing applications
Get PDFDespite the advantages of recycled randomly oriented strand (ROS) composites over recycled grinded ones, the warpage issue hinders their adaptation in the industry due to tolerance requirements. To address this challenge, ROS composites are incorporated into secondary bonded sandwich structures such that the core material ensures the straightness of the ROS composite skins. Additionally, atmospheric plasma activation (APA) is utilized to enhance the skin/core bonding to prevent skin separation under loading. The ROS composite skins are manufactured via vacuum-assisted hot press to achieve a cost-effective aerospace-grade quality. The structural integrity of the sandwich structure is assessed through flatwise tensile and edgewise compression tests, while the mechanical and thermomechanical performance is evaluated using flexural, impact, and dynamic mechanical analysis (DMA) tests. The flatwise tensile and edgewise compression tests confirm that APA effectively prevents core detachment, as evidenced by an average tensile strength of 2.28 MPa and an average compressive strength of 171.7 MPa. Moreover, the flexural and impact tests show that no premature skin failure occurs, supported by an average facing strength of 59.23 MPa in flexural testing and an average impact energy of 49.96 kJ/m(2). The DMA test indicates that most of the stiffness loss is due to the core material. This comprehensive analysis highlights recycled ROS composites as a sustainable and cost-effective alternative for quasi-isotropic skins in aerospace secondary load-bearing sandwich structures such as floors, doors, engine cowls, and spoilers
Spectrum allocation via deep Q-learning for 6G terahertz band drone communications
No full textEfficient resource allocation in Terahertz (THz) drone-to-drone communications is a critical challenge for 6G systems, as the high path loss inherent to the THz band severely hinder the establishment of reliable high-capacity links. Current approaches achieve high capacity but fail in practice due to excessive complexity. In this paper, we introduce a novel framework based on dueling double deep Q-learning that optimizes channel selection, substantially reducing computational overhead while maintaining competitive capacity performance. Simulations under both linearly-aligned and real drone trace scenarios show that our method matches state-of-the-art capacity while reducing complexity by 104, proving its viability for 6G aerial communications
Enhancing Ottoman word recognition via self-supervised pretraining using a siamese swin transformer
No full textThe Ottoman archive contains millions of handwritten documents, and their efficient management and retrieval is of paramount significance to historians. In this paper, a semi-supervised method is presented for Ottoman word recognition from handwritten historical documents. The approach involves a two-stage process: self-supervised pretraining followed by super-vised training with triplet loss. A Siamese network architecture with a Shifted Window Transformer backbone is used to learn robust feature representations. It is shown that pretraining significantly enhances the model's ability to discriminate between similar Ottoman words. The method is evaluated on a historical dataset of labeled Ottoman word crops. To foster reproducibility and future research, we release the full code and dataset at https://github.com/Sadiq04/Ottoman-KWS-IEEE-SI
The political economy of an exclusive trading company: comparative advantage, terms of trade, and distributive conflict
Get PDFWe examine the effects on a metropolis and its colony of an exclusive trading company that monopolizes the foreign trade of the colony, using Great Britain, India, and the East India Company as the central historical illustration. Theoretically, we show that such a company has incentives to impose a tax on colonial exports; that this tax may improve or deteriorate the metropolis's terms of trade, depending on whether the colonial economy is a rival or a complement to the metropolis, and these shifts in the terms of trade create both winners and losers within the metropolis. Additionally, we show that these changes influence the metropolis's GDP and income distribution, thereby shaping political support for the exclusive trading company. Our analysis sheds light on the rise and eventual dismantling of the East India Company, with the British Industrial Revolution playing a transformative role. More broadly, the paper suggests that colonial policies might be particularly burdensome for colonies with rival economies, a situation often overlooked in studies of the New World, where colonies were typically complementary to their metropolises
Forum: global perspectives on democracy support in light of the wars in Gaza and Ukraine
Get PDFThis forum critically reflects on the democracy support agenda and its future in light of the wars in Gaza and Ukraine, the decline of Western political and normative dominance, and overall global democratic backsliding. Posing four topical questions to five leading scholars in the field-from Eastern Europe, Latin America, the Middle East, North Africa, and Southeast Asia-it finds that these wars appear systemic in the sense that they sharpen already existing crises in world order. They have evidenced a structural weakness in the international liberal order (ILO): the West's selective adherence to and application of key principles of this order, effectively undermining Western credibility, influence, and its capacity to maintain the ILO and to promote democracy globally. They have also intensified practices of competitive norms promotion at the global level, with Russian norms promotion in particular scoring some successes in South America, North Africa, and Southeast Asia. This is taking place to the backdrop of multipolarity, which has led to greater strategic autonomy for states outside of the West, including in their responses to democracy promotion attempts. Taken together, these phenomena have allowed autocratic tendencies to gain strength globally, from the Mediterranean to Southeast Asia to Europe and the Americas. At the same time, democracy is also becoming more locally and regionally driven and diverse and might thus possibly become more resilient. In this new world in the making, Western democracy supporters will need to become mindful of the historical legacies of colonialism, their own internal problems with democracy, and stark normative inconsistencies of their policies-if the agenda should be kept. They will need to respect the unique historical and cultural contexts that have shaped democracies around the world and become more humble, inclusive, and dialogic with non-Western democratic middle powers such as South Africa and Brazil