Daegu Gyeongbuk Institute of Science and Technology
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Empowering tomorrow's medicine: energy-driven micro/nano-robots redefining biomedical applications
No full textMicro/nano-robots (MNRs) have gained attention as a rapidly developing field with significant potential in advanced therapies and futuristic solutions. These self-propelled robots offer a promising strategy to enhance monitoring, overcome diffusion limitations, and interact effectively with target factors. Research in MNRs has become highly influential, especially in addressing critical issues like cancer. The progression from passive micro- and nanomaterials to active MNRs and ultimately to intelligent MNRs has led to advancements in motion abilities, multifunctionality, adaptive responses, swarming behaviour, and communication among robots. Nanorobotics, featuring sophisticated submicron devices made from nanocomponents, holds great promise for revolutionizing the healthcare industry. This review aims to highlight recent progress in propulsion mechanisms, including chemically controlled micromotors, field control, and biohybrid approaches, which serve as power sources for various biomedical and environmental applications. These applications utilize different energy sources such as magnetic, light, auditory, electric, and chemical reactions, particularly in drug delivery systems for cancer treatment. This review also discusses the challenges and future directions in the practical implementation of smart MNRs, paving the way for their real-world applications.FALSEsciescopu
Event-Triggered Attitude Controller Design for Unmanned Aerial Vehicles under Cyber Attacks
No full textThis paper proposes an event-triggered attitude controller design method for unmanned aerial vehicles (UAVs) under cyber attacks. Versatile UAVs are capable of transmitting the measurement or receiving control signals through network channels. In the controller design for such UAVs, it is required to consider two distinctive features. The first one is that the strategy of updating the control signal is important for saving the limited energy consumption. The other one is that the UAVs are vulnerably exposed to threats of malicious attacks through network channels. For enhanced energy efficiency and improved stability, the event-triggered mechanism (ETM) and the attitude controller are simultaneously designed. By utilizing Lyapunov- Krasovskii functionals (LKFs), the sufficient conditions for the co-design are derived in terms of linear matrix inequalities (LMIs). For a 3-degrees of freedom (DOF) quadcopter system, the simulation results are presented to validate the proposed attitude control method. © 2024 IEEE
Ank-mediated pyrophosphate regulates shear stress-induced small extracellular vesicle production in 3D-cultured osteocytes
Get PDFOsteocytes are located in the lacunae of fluid-filled bone and communicate with neighboring or distant cells by secreting small extracellular vesicles (sEVs) and growth factors as well as via dendrite–dendrite direct connections. However, the mechanism regulating sEV production in osteocytes is yet to be elucidated. In this study, we investigated sEV production and its underlying mechanism in osteocytes cultured on a three dimensional (3D) scaffold. We employed a perfusion system to apply shear stress stimulation to MLO-Y4 cells cultured on a 3D biphasic calcium phosphate (BCP) scaffold and analyzed sEV production and gene expression using RNA sequencing. We found that the expression of genes associated with sEV biogenesis and the secretory pathway were enhanced by fluid shear stress in MLO-Y4 cells cultured on a 3D BCP scaffold. In particular, fluid shear stress induced the expression of Ank, a pyrophosphate transporter, in 3D-cultured MLO-Y4 cells. The role of Ank in sEV production was further examined. Probenecid, an Ank inhibitor, significantly suppressed shear stress-induced sEV production, whereas Ank cDNA overexpression stimulated it. The inhibition of shear stress-induced sEV production by probenecid was recovered by the exogenous addition of pyrophosphate to MLO-Y4 cells. These findings suggest that shear stress-mediated sEV production in 3D-cultured osteocytes is regulated by extracellular pyrophosphate transported by Ank. © 2024 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.TRUEsciescopuskc
Conserved pattern-based classification of human odorant receptor multigene family
Get PDFConserved protein-coding sequences are critical for maintaining protein function across species. Odorant receptors (ORs), a large poorly understood multigene family responsible for odor detection, lack comprehensive classification methods that reflect their functional diversity. In this study, we propose a new approach called conserved motif-based classification (CMC) for classifying ORs based on amino acid sequence similarities within conserved motifs. Specifically, we focused on three well-conserved motifs: MAYDRYVAIC in TM3, KAFSTCASH in TM6, and PMLNPFIY in TM7. Using an unsupervised clustering technique, we classified human ORs (hORs) into two main clusters with six sub-clusters. CMC partly reflects previously identified subfamilies, revealing altered residue positions among the sub-clusters. These altered positions interacted with specific residues within or adjacent to the transmembrane domain, suggesting functional implications. Furthermore, we found that the CMC correlated with both ligand responses and ectopic expression patterns, highlighting its relevance to OR function. This conserved motif-based classification will help in understanding the functions and features that are not understood by classification based solely on entire amino acid sequence similarity. © The Author(s) 2024.TRUEsciescopu
Next-Generation Sensors with Three-Dimensional Micro-/Nano-Structures
Get PDFInnovative sensor technologies are crucial in various fields, including environmental monitoring, healthcare, and industrial appli-cations. Sensor fabrication at the nano/microscale and the introduction of 3D structures can improve the sensitivity, response time, and overall performance of the sensor. Specifically, 3D architectures allow improved surface areas and interactions with target substances, whereas miniaturization facilitates improved sensitivity and integration into compact devices. This review discusses the recent advance-ments in five types of sensors, namely, gas sensors, strain sensors, environmental sensors, photodetectors, and biosensors, emphasizing the importance of structural innovations and size reduction in enhancing sensing capabilities. The essential design, fabrication methods, and potential applications are explored, highlighting the transformative impact of these technologies on future sensor development. © 2024, Korean Sensors Society. All rights reserved.TRUEscopuskc
Modulation of Li+ microenvironment in liquid electrolyte for interface design of Li-metal anodes
No full textWhile lithium metal anodes (LMAs) offer the highest energy density, positioning them as a promising material for graphite, they suffer from uneven electroplating morphology and the formation of Li dendrites. Given the pivotal role of the solid-electrolyte interphase (SEI), which is formed by electrolyte decomposition, in mitigating dendritic growth, extensive research has been conducted on liquid electrolytes in Li metal batteries (LMBs). This mini-review presents the historical advancements in LMB electrolytes, focusing on modulating the Li+ microenvironment and LMA interface chemistry to inhibit Li dendrite formation. We traced the evolution of LMB electrolytes from traditional formulations to advanced designs. In particular, the reinforcement of the SEI and the compact morphology of the deposited Li are deeply discussed at each advancement in liquid electrolytes. We subsequently identify common characteristics among these advanced electrolytes and conclude by discussing future directions and strategies for rational design. © 2024 Korean Chemical Society, Seoul & Wiley-VCH GmbH.FALSEsciescopuskc
TRANSITION METAL-V-O-H-based electrode composition of calcium ion battery and calcium ion battery comprising the same
No full text본 발명은 칼슘 이온 전지용 전극 조성물이며, AxV2O5ㆍy(H2O)를 포함하고, 상기 A는 전이금속이고, x는 0.1 003c# x 003c# 2이고, 상기 y는 0 003c# y 003c# 9인 것을 특징으로 하는 칼슘 이온 전지용 전극 조성물을 제공한다. 이때 특히 A는 예시적으로, 망간 또는 크롬이다. 본 발명에 따른 칼슘 이온 전지용 전극 조성물은 기존에 이용된 1가의 양이온인 리튬 이온 대신 2가의 양이온인 칼슘 이온을 가역적으로 탈ㆍ삽입함으로써 전지의 성능이 우수한 효과가 있다
Two-step Adaptive Target Detection Scheme Using Beam-steering FMCW Radar Sensors
Get PDFThis letter proposes a two-stage adaptive target detection approach using a beam-steered frequency-modulated continuous wave (FMCW) radar sensor. In the first step, coarse estimation was performed using multiple sharped beams, where the presence of a target was determined using only a portion of the sampled beat signals. In the second step, a high-resolution range-Doppler (RD) map was generated using the entire information about the beat signal pertaining to the transmitted beams estimated to contain the target. Angle estimation was accomplished through digital beamforming based on the enhanced RD map. Furthermore, to verify the effectiveness of the proposed algorithm, high-resolution target detection experiments were conducted using a 24-GHz FMCW radar, while complexity reduction was evaluated in terms of the required memory size. © (2024), (Korean Institute of Electromagnetic Engineering and Science). All rights reserved.TRUEsciekc
Turing instability and attractor bifurcation for the general Brusselator model
No full textIn this paper, we analyze the dynamic bifurcation of the general Brusselator model when the order of reaction is p ∈ (1, ∞). We verify that the Turing instability occurs above the critical control number and obtain a rigorous formula for the bifurcated stable patterns. We define a constant sN that gives a criterion for the continuous transition. We obtain continuous transitions for sN > 0, but jump transitions for sN < 0. By using this criterion, we prove mathematically that higher-molecular reactions are rarely observed. We also provide some numerical results that illustrate the main results. © 2024 American Institute of Mathematical Sciences. All rights reserved.FALSEsciescopu
Extreme heat flux cooling from functional copper inverse opal-coated manifold microchannels
No full textThe utilization of a hierarchical microstructure and three-dimensional (3D) manifold for liquid delivery and liquid/vapor extraction could potentially improve the single-phase/two-phase thermal performance of microcoolers for high-heat-flux microelectronics applications exceeding 1 kW cm−2. In this work, we utilize a conformal coating of 8-μm-thick copper inverse opal (CuIO) films with ∼ 5-μm pore size on silicon microchannels in combination with a polydimethylsiloxane 3D manifold to remove heat fluxes up to 1147 W cm−2 under a water inlet temperature and flow rate of 20 °C and 200 g min−1, respectively. We achieved a convective thermal resistance of 0.068 cm2 K W−1 and total pressure drop of 32 kPa. Moreover, owing to copper micropores, a better hot-spot temperature uniformity (<6 K) with the aid of improved boiling nucleation was achieved. The interchip microchannel with a functional porous material and 3D manifold offers a disruptive thermal-management solution for high-performance electronic devices such as data centers, defense weapons, and power electronics for electric vehicles. © 2024 Elsevier LtdFALSEsciescopu