166 research outputs found
SI – Supplemental material for Three-dimensional printing of a patient-specific engineered nasal cartilage for augmentative rhinoplasty
No full textSupplemental material, SI for Three-dimensional printing of a patient-specific engineered nasal cartilage for augmentative rhinoplasty by Hee-Gyeong Yi, Yeong-Jin Choi, Jin Woo Jung, Jinah Jang, Tae-Ha Song, Suhun Chae, Minjun Ahn, Tae Hyun Choi, Jong-Won Rhie and Dong-Woo Cho in Journal of Tissue Engineering</p
Experimental identification of I-mode characteristics at the edge of FIRE mode in KSTAR
No full textThe edge region of the recently discovered fast ion-regulated enhancement mode (FIRE mode) (Han and Park et al 2022 Nature 609 269–275), which primarily operates in the unfavorable ion drift configuration, is investigated in detail for the first time. An ion temperature pedestal is identified, while the edge electron density profile remains at low-confinement mode (L-mode) level, displaying characteristics of the edge profiles in improved energy confinement mode (I-mode). The weakly coherent mode (WCM) is observed at around 50 kHz in the spectrum of edge electron density fluctuations measured by beam emission spectroscopy. The weakly coherent feature becomes more pronounced as the amplitude of intermediate-frequency fluctuations (approximately 10–30 kHz) decreases, coinciding with a rise in the height of the temperature pedestal. The WCM propagates in the ion diamagnetic drift direction in the laboratory frame, but its propagation direction in the E × B flow frame has yet to be determined. Nonlinear phase coupling between the low-frequency density fluctuation components and the WCMs is identified, indicating the presence of zonal density. This coupling typically occurs as the H-mode transition approaches, and its potential link to a regulatory process is discussed. When the coupling manifests, intermittent bursts are observed concurrently, not just at the radial location where the WCM amplitude peaks, but throughout the edge region. No other coherent oscillations with finite frequency have been detected thus far
Polytypic Two-Dimensional FeAs with High Anisotropy
No full textIn the realm of two-dimensional (2D) crystal growth, the chemical composition often determines the thermodynamically favored crystallographic structures. This relationship poses a challenge in synthesizing novel 2D crystals without altering their chemical elements, resulting in the rarity of achieving specific crystallographic symmetries or lattice parameters. We present 2D polymorphic FeAs crystals that completely differ from bulk orthorhombic FeAs (Pnma), differing in the stacking sequence, i.e., polytypes. Preparing polytypic FeAs outlines a strategy for independently controlling each symmetry operator, which includes the mirror plane for 2Q-FeAs (I4/mmm) and the glide plane for 1Q-FeAs (P4/nmm). As such, compared to bulk FeAs, polytypic 2D FeAs shows highly anisotropic properties such as electrical conductivity, Young’s modulus, and friction coefficient. This work represents a concept of expanding 2D crystal libraries with a given chemical composition but various crystal symmetries. © 2023 American Chemical Society.11Nsciescopu
Development of thickened flame model on an open-source CFD code
No full text학위논문(석사) - 한국과학기술원 : 항공우주공학과, 2022.2,[vii, 51 p. :]연소 현상의 고정밀도 수치 해석을 위해서는 화염을 충분히 모사할 수 있는 격자를 사용하여야 한다. 이러한 작은 크기의 격자를 사용하게 되면, 격자 수 증가로 인한 많은 계산 소요가 요구된다. 메탄에 비해 더 얇은 화염두께를 가지는 수소는 화염 내부 모사를 위해 더 작은 크기의 격자가 요구되며, 계산 소요 문제가 더욱 대두된다. 본 연구에서는 수소 연소 시뮬레이션의 정확도를 높이면서 계산 소요를 줄이기 위해 화염의 두께를 인위적으로 늘여 화염 내부에 충분한 격자 밀집도를 확보할 수 있는 thickened flame 모델을 구현하였다. 그러나 thickened flame 모델을 적용할 경우, 수소의 스트레인 율 특성이 보존되지 않는 문제가 발생한다. 본 연구에서는 새로운 두께 모델인 동적 보정 모델을 제안하여 수소 화염의 스트레인 율 특성 보존 문제를 해결하였다. 오픈소스 해석코드인 OpenFOAM을 이용하여 thickened flame 모델과 동적 보정 모델을 구현하였으며, 이를 3가지 시뮬레이션을 통해 검증하였다. 먼저, 1차원 화염 시뮬레이션을 통해 thickened flame 모델이 층류화염속도를 유지하며 층류화염두께가 두께 인자에 따라 증가하는 것을 확인하였다. 분젠 화염 시뮬레이션을 통해 2, 3차원에서도 층류화염속도가 유지되며 화염의 두께가 두께 인자에 따라 증가하는 것을 확인하였다. 마지막으로, 정체 화염 시뮬레이션을 통해 동적 보정 모델을 사용하였을 때, 여러 당량비 조건에서 수소의 스트레인 율 특성이 보존됨을 확인하였다.한국과학기술원 :항공우주공학과
Substituents engineered deep-red to near-infrared phosphorescence from tris-heteroleptic iridium(III) complexes for solution processable red-NIR organic light-emitting diodes
No full textResearch on near-infrared- (NIR-) emitting materials and devices has been propelled by fundamental and practical application demands surrounding information-secured devices and night-vision displays to phototherapy and civilian medical diagnostics. However, the development of stable, highly efficient, low-cost NIR-emitting luminophores is still a formidable challenge owing to the vulnerability of the small emissive bandgap toward several nonradiative decay pathways, including the overlapping of ground- and excited-state vibrational energies and high-frequency oscillators. Suitable structural designs are mandatory for producing an intense NIR emission. Herein, we developed a series of deep-red to NIR emissive iridium(III) complexes (Ir1–Ir4) to explore the effects of electron-donating and electron-withdrawing substituents anchored on the quinoline moiety of (benzo[b]thiophen-2-yl)quinoline cyclometalating ligands. These substituents help engineer the emission bandgap systematically from the deep-red to the NIR region while altering the emission efficiencies drastically. Single-crystal X-ray structures authenticated the exact coordination geometry and intermolecular interactions in these new compounds. We also performed an in-depth and comparative photophysical study in the solution, neat powder, doped polymer film, and freeze matrix at 77 K states to investigate the effects of substitution on the excited-state properties. These studies were conducted in conjunction with density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations. Most importantly, the –CH3 substituted Ir1, unsubstituted Ir2, and –CF3 substituted complex (Ir4) were promising novel compounds with bright phosphorescence quantum efficiency in doped polymer films. Using these novel molecules, deep-red to NIR emissive organic light-emitting diodes (OLEDs) were fabricated using a solution-processable method. The unoptimized device exhibited maximum external quantum efficiency (EQE) values of 2.05% and 2.11% for Ir1 and Ir2, respectively.11Nsciescopu
Tissue printing for engineering transplantable human parathyroid patch to improve parathyroid engraftment, integration, and hormone secretion in vivo
No full textDuring thyroid surgery, some parathyroid glands fail to maintain their function, therefore, they are unavoidably detached from the patient. For the purpose of re-preservation of the function, they are minced into small segments and transplanted into the fat or muscle layer. Yet, this method of auto-grafting the parathyroid glands is frequently unsuccessful due to its poor interaction and engraftment with the native tissue, eventually leading to the dysfunction of the parathyroid hormone (PTH) secretion. In this study, we suggest a methodology to restore parathyroid activity through the introduction of the 'tissue printing' concept. Parathyroid glands of patients with secondary hyperparathyroidism were minced into the fragments smaller than 0.5 x 0.5 mm, which is in common with the traditional surgical method. These parathyroid tissues (PTs) were uniformly mixed with the adipose-derived decellularized extracellular matrix (adECM) bioink that protects the PTs from hostile in vivo environments and promote initial engraftment. PTs-encapsulated adECM bioink (PTs-adECM) was then printed onto the pre-designed polycaprolactone (PCL) mesh to produce patch-type PTs construct, which functions as a mechanical support to further enhance long-term in vivo stability. The engineered patch was transplanted subcutaneously into rats and harvested after 4 weeks. In vivo results showed that the engineered patches were well engrafted and stabilized in their original position for 4 weeks as compared with PTs only. Immunohistochemistry results further revealed that the concentration of PTH was approximately 2.5-fold greater in rats engrafted in the patch. Taken together, we envision that the novel concept 'tissue printing' over cell printing could provide a closer step towards clinical applications of 3D bioprinting to solve the unmet need for parathyroid surgery method.11Nsciescopu
Three-dimensional printing of a patient-specific engineered nasal cartilage for augmentative rhinoplasty
No full textAutologous cartilages or synthetic nasal implants have been utilized in augmentative rhinoplasty to reconstruct the nasal shape for therapeutic and cosmetic purposes. Autologous cartilage is considered to be an ideal graft, but has drawbacks, such as limited cartilage source, requirements of additional surgery for obtaining autologous cartilage, and donor site morbidity. In contrast, synthetic nasal implants are abundantly available but have low biocompatibility than the autologous cartilages. Moreover, the currently used nasal cartilage grafts involve additional reshaping processes, by meticulous manual carving during surgery to fit the diverse nose shape of each patient. The final shapes of the manually tailored implants are highly dependent on the surgeons' proficiency and often result in patient dissatisfaction and even undesired separation of the implant. This study describes a new process of rhinoplasty, which integrates three-dimensional printing and tissue engineering approaches. We established a serial procedure based on computer-aided design to generate a three-dimensional model of customized nasal implant, and the model was fabricated through three-dimensional printing. An engineered nasal cartilage implant was generated by injecting cartilage-derived hydrogel containing human adipose-derived stem cells into the implant containing the octahedral interior architecture. We observed remarkable expression levels of chondrogenic markers from the human adipose-derived stem cells grown in the engineered nasal cartilage with the cartilage-derived hydrogel. In addition, the engineered nasal cartilage, which was implanted into mouse subcutaneous region, exhibited maintenance of the exquisite shape and structure, and striking formation of the cartilaginous tissues for 12 weeks. We expect that the developed process, which combines computer-aided design, three-dimensional printing, and tissue-derived hydrogel, would be beneficial in generating implants of other types of tissue.11Ysciescopu
Wearable Robot Embedded Human Muscle Activity Monitoring System and Human-Oriented Joint Torque Calculation
No full textAmong various robotic devices, wearable robots physically interact with the musculoskeletal system of the human body. For complete paraplegic patients, the motor torque of the wearable robot is the only internal torque of the combined human-robot system and generates the motion of the human-robot. In the case of incomplete paraplegia, the joint torque generated by the human and the motor torque of the robot are combined to create the movement of the human body and the robot. Interaction torque is the assistive torque received by humans. In this paper, we introduce a soft pneumatic muscle sensor system that can measure the interaction torque between a human and a wearable robot. The system was embedded in the fabric bands of the wearable robot Angel Legs to measure muscle activity and interaction torque during robot operation. As a preliminary study, we propose a knee joint torque experiment. Additional research progress and experimental results will be presented at the conference session
Deep Learning for Toxicity and Disease Prediction
No full textThis eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contac
STFTransNet: A Transformer Based Spatial Temporal Fusion Network for Enhanced Multimodal Driver Inattention State Recognition System
No full textRecently, studies on driver inattention state recognition as an advanced mobility application technology are being actively conducted to prevent traffic accidents caused by driver drowsiness and distraction. The driver inattention state recognition system is a technology that recognizes drowsiness and distraction by using driver behavior, biosignals, and vehicle data characteristics. Existing driver drowsiness detection systems are wearable accessories that have partial occlusion of facial features and light scattering due to changes in internal and external lighting, which results in momentary image resolution degradation, making it difficult to recognize the driver’s condition. In this paper, we propose a transformer based spatial temporal fusion network (STFTransNet) that fuses multi-modality information for improved driver inattention state recognition in images where the driver’s face is partially occluded by wearing accessories and the instantaneous resolution is degraded due to light scattering from changes in lighting in a driving environment. The proposed STFTransNet consists of (i) a mediapipe face mesh-based facial landmark extraction process for facial feature extraction, (ii) an RCN-based two-stream cross-attention process for learning spatial features of driver face and body action images, (iii) a TCN-based temporal feature extraction process for learning temporal features of extracted features, and (iv) an ensemble of spatial and temporal features and a classification process to recognize the final driver state. As a result of the experiment, the proposed STFTransNet achieved an accuracy of 4.56% better than the existing VBFLLFA model in the NTHU-DDD public DB, 3.48% better than the existing InceptionV3 + HRNN model in the StateFarm public DB, and 3.78% better than the existing VBFLLFA model in the YawDD public DB. The proposed STFTransNet is designed as a two-stream network that can input the driver’s face and action images and solves the degradation in driver inattention state recognition performance due to partial facial feature occlusion and light blur through spatial feature and temporal feature fusion
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