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Viable hydrate-based CO2 capture facilitated by cyclopentane hydrate seeds and tailored kinetic promoters
No full textWith the increasing demand for scalable carbon capture technologies, environmentally benign clathrate hydrate-based systems have gained attention. However, unpredictable nucleation delays, slow hydrate formation kinetics, and reliance on energy intensive agitation methods have impeded industrial adoption of CO2 hydrates. This study reports significantly high CO2 uptakes of 0.1503 mol CO2/mol H2O for structure I (sI) CO2 hydrates and 0.0693 mol CO2/mol H2O for structure II (sII) cyclopentane (CP)-CO2 hydrates under static conditions. Critically, the introduction of hydrate seeds and specifically tailored kinetic promoters lead to instantaneous nucleation, an occurrence not previously reported. Our findings, supported by kinetic analyses and molecular dynamics simulations, reveal that sodium alkyl sulfate, which is effective in various hydrate systems including natural gas storage, inhibited sI CO2 hydrate formation under static conditions due to interference by its long alkyl chains with CO2 interactions. In contrast, moderate hydrophobic amino acids, particularly L-methionine, significantly enhanced hydrate formation kinetics through optimal interactions with CO2 molecules. Ex-situ and in-situ Raman spectroscopy confirmed that in sII CP-CO2 systems, the use of L-methionine resulted in high CO2 uptake due to co-enclathration of CO2 and CP molecules, whereas the surfactant molecules reduced CO2 storage capacity by promoting rapid pure CP hydrate growth. These results offer critical guidelines for promoter selection and significantly advance the industrial viability of hydrate-based CO2 capture technologies. © 2025 Elsevier B.V.FALSEsciescopu
Molecular Engineering of Peptoid Scaffolds for Spatial Display of Functional Groups: Siderophore-Mimic Peptoids and Pigment-Displaying Peptoids
No full textThis thesis explores the versatile applications of peptoids due to their tunable side chains and well-defined secondary structures. It consists of four studies, each presented in separate chapters. Chapter 1 serves as an introduction. Chapters 2 and 3 develop design principles for siderophore-inspired compounds and their applications in antibacterial therapy. Chapter 2 details novel cyclic peptoids with catechol moieties mimicking natural siderophores' iron-binding, which forms stable tris(catecholato) iron(III) complexes. Conjugated with antibiotics, these compounds showed significant activity against drug-resistant Acinetobacter baumannii. Chapter 4 incorporates chiral submonomers into peptoids, producing helices with circularly polarized luminescence through controlled backbone homogeneity. Chapter 5 uses peptoids to precisely arrange donor-acceptor pigments for studying electron transfer kinetics, revealing improved electron transfer with an anthracene/DMA pair. These findings highlight peptoids’ potential in developing antibacterial agents and optically active materials.Docto
Highly sensitive double-grating interferometer for direct measurement of a neutral helium gas density in a capillary cell
No full textWe developed a highly sensitive double-grating interferometer using four probe beams, which can measure one order of magnitude smaller phase shifts compared with other conventional interferometers. To achieve the unprecedented sensitivity, a highly dynamic 16-bit CCD camera was used and the balanced detection technique with four probe beams was employed in the 2-dimensional (2-D) interferometry for the first time. By using this interferometer, we could directly measure a low helium (He) gas density of n similar or equal to 1 x 1017 cm-3 in a capillary gas cell for the laser-plasma acceleration research, which is almost impossible with other conventional laser interferometers. This interferometer may provide a new tool for applications with extremely small phase shifts in science. (c) 2025 Optica Publishing Group under the terms of the Optica Open Access Publishing AgreementTRUEsciescopu
Speckle Noise Reduction in FMCW LiDAR Using Intensity-Weighted Signal Acquisition with a Quadrant Photodiode Receiver
No full textFrequency modulated continuous wave (FMCW) LiDAR has gained attention for its robustness in harsh outdoor environments, leveraging an interferometry based distance measurement principle. However, its accuracy is significantly degraded by speckle noise caused by surface roughness and optical instability. In this paper, we propose a speckle noise reduction method using a quadrant photodiode (QPD), which spatially separates the received beam and applies intensity weighted averaging to suppress amplitude fluctuations. The proposed method is mathematically formulated and validated through experimental comparison with conventional interference signals. Experimental results show that the proposed approach effectively suppresses necking effects and reduces frequency measurement errors from 25 kHz to 5 kHz, achieving both the frequency and distance resolution limits of the developed FMCW LiDAR system. This confirms that the proposed method enhances the stability and reliability of interference signal acquisition, particularly in high-speed scanning environments. © 2025 Elsevier B.V., All rights reserved.FALSEscopu
Guaranteeing Equitable Musical Collaboration: Lessons Learned from the Music-Making Activities in Mixed-Hearing Groups
No full textIntegrating mixed-hearing groups in musical collaboration presents unique challenges and opportunities for their communication and equal contribution. This observational study aims to explore their collaborative work, focusing on the way for equitable music-making. We observed two music-making workshops to identify the potential and dynamics of their musical collaboration. While the frst workshop proceeded in a traditional manner of music-making, the second workshop used an assistive tool with multimodality. Our fndings highlight the dynamics in musical collaboration that foster engagement and bridge interaction gaps. In turn, sensory inclusion with multimodal music-making promoted role transition in mixed-hearing groups and their equal contributions, leading to the embracing of diverse cultural perspectives. Based on the insights derived from the observations, we propose a design guideline and future research directions for harnessing group dynamics and building equitable musical collaborations for an inclusive environment for mixed-hearing groups. © 2025 Copyright held by the owner/author(s).TRUEscopu
Toxicological effects of microplastic fibers from different disposable face masks on Caenorhabditis elegans
No full textDuring the COVID-19 pandemic, the widespread use of disposable face masks generated substantial waste, much of which ends up in terrestrial environments. However, the impact of this discarded material on soil ecosystems remains poorly understood. This study investigated the toxicological effects of microplastics derived from three types of disposable face masks (KF94, medical, and particulate respirator) and a polypropylene reference material on the soil nematode Caenorhabditis elegans (C. elegans). Exposure to 0.3 % (w/w, microplastic/soil) microplastics from KF94 masks and particulate respirators significantly reduced offspring numbers. Mass spectrometry (MS)-based metabolomic analysis revealed distinct metabolic alterations in C. elegans exposed to microplastics. Both KF94 masks and particulate respirators commonly disrupted the polyamine biosynthesis pathway but exhibited differing impacts on associated metabolites. High-resolution MS analysis of plastic additives extracted from the masks suggested that these differential metabolic changes could be attributed to various additives, including phthalates known to exhibit reproductive toxicity in C. elegans. These findings highlight the potential risk of plastic additives from disposed face masks disrupting soil ecosystems, raising concerns about their long-term environmental impact on soil health and biodiversity.TRUEsciescopu
Individual Differences in Korean Word Recognition During Reading
No full textAdults are generally proficient in their native language, effortlessly processing linguistic information. Nonetheless, individual differences in lexical processing, particularly in word recognition, exist even among skilled readers. In this chapter, I reviewed some interesting studies on individual differences in Korean lexical processing and introduced some effective assessment tools such as the Korean Author Recognition Test (KART) and the bisyllabic onset test to measure individual differences in language processing among Korean adults. Multiple studies have shown that individual differences in language proficiency or word knowledge affect lexical access in Korean, even among native speakers. These results have implications for how crucial individual differences in language proficiency should be considered with respect to Korean word recognition. © 2025 The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG.FALSEforeig
Imperfect Image-Space Control Variates for Monte Carlo Rendering
No full textWe present an image-space control variate technique to improve Monte Carlo (MC) integration-based rendering. Our method selects spatially nearby pixel estimates as control variates to exploit spatial coherence among pixel estimates in a rendered image without requiring analytic modeling of the control variate functions. Employing control variates is a classical and well-established technique for variance reduction in MC integration, typically relying on the assumption that the expectations of control variates are readily obtainable. When this condition is met, control variate theory offers a principled framework for optimizing their use by adjusting coefficients that determine the relative contribution of each control variate. However, our image-space approach introduces a technical challenge, as the expectations of the pixel-based control variates are unknown and must be estimated from additional MC samples, which are unbiased but inherently noisy. In this paper, we propose a control variate estimator designed to optimally leverage such imperfect control variates by relaxing the traditional requirement that their expectations are known. We demonstrate that our approach, which estimates the optimal coefficients while explicitly accounting for uncertainty in the expectation estimates, effectively reduces the variance of MC rendering across various test scenes.TRUEsciescopu
Excited-state proton transfer of weak and medium-strength photoacids in confined methanol-in-oil reverse micelles
No full textThis study explores the excited-state proton transfer (ESPT) dynamics of weak and medium-strength photoacids, 8-hydroxypyrene-1,3,6-trisulfonic trisodium salt (pyranine; HPTS), D-luciferin, and 2-cyano-6-hydroxybenzothiazole (CBTOH), confined within water-in-oil and methanol-in-oil reverse micelles (RMs). We extend the previous work on the ESPT dynamics of HPTS in Igepal RMs to several weak or medium-strength photoacids confined in the RMs. These photoacids exhibit proton transfer rate constants on the order of 109 s-1 in small RMs, which are comparable to the solvation dynamics inside the RMs. This suggests that the solvation dynamics govern the ESPT rates in the RMs, irrespective of the core polar solvent characteristics.FALSEsciescopuskc