• Korean Journal of Radiology
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• v.21 no.10
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• pp.1187-1195
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• 2020

Objective: This study aimed to determine the sonographic features suggestive of extrathyroidal extension (ETE) of thyroid cancers. Materials and Methods: We retrospectively reviewed the sonographic images of 1656 consecutive patients who had undergone thyroidectomy in 2017. The diagnostic performance of sonographic features suggestive of ETE was evaluated using operation and histopathologic reports. Sonographic features for gross ETE to the strap muscle and minor ETE were assessed for thyroid cancer abutting the anterolateral thyroid capsule. Sonographic features for tracheal invasion were assessed according to whether the angle between the tumor and the trachea was an acute, right, or obtuse angle. Sonographic features for recurrent laryngeal nerve (RLN) invasion were assessed based on the association between the tumor and tracheoesophageal groove (TEG) as preserved normal tissue, abutting or protruding into the TEG. Results: ETE was observed in 783 patients (47.3%), including 123 patients with gross ETE (7.4% [strap muscle, n = 97; RLN, n = 24; and trachea, n = 14]) and 660 patients with minor ETE (39.9%). Regarding the diagnosis of gross and minor ETE to the strap muscle, sonographic features of replacement of the strap muscle and capsular disruption showed the highest positive predictive value (75.9% and 58.5%, respectively). Thyroid cancer forming an obtuse angle with the trachea had the highest sensitivity for the diagnosis of tracheal invasion (85.7%), and thyroid cancer protrusion into the TEG showed the highest sensitivity for the diagnosis of RLN (83.3%). Conclusion: Sonography is considered beneficial in the diagnosis of ETE to the strap muscle, trachea, and RLN. Assessment of ETE is important for the accurate staging of thyroid cancer, which in turn determines the extent of surgery or whether active surveillance is appropriate or not.

• Journal of Chest Surgery
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• v.51 no.2
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• pp.114-121
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• 2018

Background: Unfractionated heparin is commonly used for anticoagulation in extracorporeal membrane oxygenation (ECMO). Several studies have shown that nafamostat mesilate (NM) has comparable clinical outcomes to unfractionated heparin. This study compared anticoagulation with NM and heparin in a large-animal model. Methods: Beagle dogs (n=8; weight, 6.5-9 kg) were placed on venovenous ECMO. Blood samples were taken every hour and the following parameters were compared: hemoglobin level, activated partial thromboplastin time (aPTT), thromboelastography (TEG) data, platelet function, and inflammatory cytokine levels. Results: In both groups, the aPTT was longer than the baseline value. Although the aPTT in the NM group was shorter than in the heparin group, the TEG parameters were similar between the 2 groups. Hemoglobin levels decreased in both groups, but the decrease was less with NM than with heparin (p=0.049). Interleukin $(IL)-1{\beta}$ levels significantly decreased in the NM group (p=0.01), but there was no difference in the levels of tumor necrosis factor alpha or IL-10 between the 2 groups. Conclusion: NM showed a similar anticoagulant effect to that of unfractionated heparin, with fewer bleeding complications. NM also had anti-inflammatory properties during ECMO. Based on this preclinical study, NM may be a good alternative candidate for anticoagulation in ECMO.

• Transactions of the Korean hydrogen and new energy society
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• v.31 no.5
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• pp.405-410
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• 2020

In this literature, we are introduce a basic design of multi energy hub based on natural gas governor station. Multi energy hub consists of turbo expender generator, phosphoric acid fuel cell, pressure swing adsorption, H₂ charging station, utilities and etc. We design a hybrid energy hub system that provides energy using these complex energies, and calculates the amount of electricity that can be produced and the amount of hydrogen charged through the process analysis. TEG and phosphoric acid fuel cell produce 2,290 to 2,380 kW and can supply electricity to 500 houses. In addition, By-product H₂ gas is refined to H₂ vehicle fuel. This will help maximize the balance of energy demand and supply and improve national energy efficiency by integrating unused decompression energy power generation technology and various power generation/heat source technologies.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.8
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• pp.3168-3186
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• 2020

Automatic topic essay generation (TEG) is a controllable text generation task that aims to generate informative, diverse, and topic-consistent essays based on multiple topics. To make the generated essays of high quality, a reasonable method should consider both diversity and topic-consistency. Another essential issue is the intrinsic link of the topics, which contributes to making the essays closely surround the semantics of provided topics. However, it remains challenging for TEG to fill the semantic gap between source topic words and target output, and a more powerful model is needed to capture the semantics of given topics. To this end, we propose a pretraining-based contextual self-attention (PC-SAN) model that is built upon the seq2seq framework. For the encoder of our model, we employ a dynamic weight sum of layers from BERT to fully utilize the semantics of topics, which is of great help to fill the gap and improve the quality of the generated essays. In the decoding phase, we also transform the target-side contextual history information into the query layers to alleviate the lack of context in typical self-attention networks (SANs). Experimental results on large-scale paragraph-level Chinese corpora verify that our model is capable of generating diverse, topic-consistent text and essentially makes improvements as compare to strong baselines. Furthermore, extensive analysis validates the effectiveness of contextual embeddings from BERT and contextual history information in SANs.

• Journal of Energy Engineering
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• v.29 no.1
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• pp.75-84
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• 2020

This study investigates a simple, yet effective and affordable, manufacturing method to increase the electrical efficiency by triboelectric generator (TEG) applying 3D printers. In this study, we propose the newly manufacturing method for producing a macroscale surface patterning. Overall experiments were conducted in designed test-bed chamber system which can control the magnitude and frequency of the frictional force and the relative humidity. Furthermore, we can demonstrate the voltage enhancement of macroscale surface patterns about 1.6-fold. The peak voltage producing by TEG was as high as 18 V. In comparison with conventional process that employ micro- and nanoscale patterns, the proposed process by 3D printer is faster and more suitable for mass production.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.577-580
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• 2014

In this paper an auto-switching dual-input energy harvesting circuit is proposed. Since the maximum power points of a thermoelectric generator(TEG) output and a vibration device(PEG) output is 1/2 of their open-circuit voltage, an identical MPPT controller can be used for both energy sources. The proposed circuit monitors the outputs of the TEG and PEG, and chooses the energy source generating a higher output using an auto-switching controller, and then harvests the maximum power from the selected device using a MPPT controller. The harvested energy is boosted through a charge pump and stored in a storage capacitor. The stored energy is provided to a load through a PMU(Power Management Unit). The proposed circuit is designed in a $0.35{\mu}m$ CMOS process and its functionality has been verified through extensive simulations. The designed chip occupies $1.4mm{\times}1.2mm$ including pads.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.3
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• pp.292-297
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• 2023

Triboelectric devices are attracting attention from researchers as self-powered electronic systems that can instantly convert mechanical input into electrical energy output. To improve triboelectric energy harvesting performance, increasing the number of contacts as well as the contact area has been carried out by numerous researchers. In this study, we design a shaker-type energy harvester which is called as maracas triboelectric generator (M-TEG), inspired by the structure of maracas, one of the musical percussion instruments. A tripod frame is inserted to the inside of a cylindrical case, which is a device with the electrodes of aluminum and copper. Then, the triboelectric energy harvesting characteristics between polypropylene (PP) balls and the electrodes are measured. The M-TEG with the frame generates the energy harvesting signals up to ~100 V and ~2.5 ㎂ due to larger contact area and numbers, which enhances the voltage and current output by 250% and 610% compared to that without the frame, respectively. This study presents the feasibility of self-powered sensors and toys using improved triboelectric energy performance with a low-cost and simple manufacturing process in the interesting structure.

• Korean Journal of Veterinary Service
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• v.45 no.1
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• pp.55-61
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• 2022

In veterinary medicine, a variety of disease are known to cause coagulation abnormalities. Identification of these coagulation abnormalities have been relied on traditional coagulation assays(platelet concentration, aPTT, PT, D-dimer, fibrinogen) which take only a small part of the coagulation pathways rather than global hemostatic capacity. Among of the hypercoagulable diseases, cardiovascular disease, such as mitral valvular disease, was not regarded as the cause of the hypercoagulability. The value of a thromboelastography (TEG) as an early predictor of coagulopathy, especially hypercoagulability, has been founded. It was associated with decreased R and K values, and increased MA and α angle. The objective of this study was to compare thromboelastography results and those of traditional coagulation tests between twenty adult dogs with mitral insufficiency (MVI group) and eleven adult healthy dogs (Healthy group). As a results, MA values in the patients with mitral insufficiency (68.8±7.8 mm) were significantly higher than the normal patients (60.4±4.8 mm) (P value<0.05). Although a little report has been reported in veterinary medicine, platelet activation seems to be related with hypercoagulability in MVI patients in human medicine. The result of this report can support this pathophysiology in veterinary medicine. In addition to traditional coagulation assay, global assessment of coagulopathy using TEG, especially ability to detect hypercoagulability, may be useful for customized treatment in MVI patients. To achieve this, further study is needed to define pathophysiology and effect of medication.

• Restorative Dentistry and Endodontics
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• v.47 no.4
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• pp.42.1-42.11
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• 2022

Objective: This study investigated the effects of various concentrations of sodium hypochlorite (NaOCl) on human whole-blood clotting kinetics, the structure of the blood clots formed, and transforming growth factor (TGF)-β1 release. Materials and Methods: Human whole blood was collected from 5 healthy volunteers and divided into 4 groups: CG (control, 0.5 mL of blood), BN_0.5 (0.5 mL of blood with 0.5 mL of 0.5% NaOCl), BN₃ (0.5 mL of blood with 0.5 mL of 3% NaOCl), and BN_5.25 (0.5 mL of blood with 0.5 mL of 5.25% NaOCl). The effects of NaOCl on clotting kinetics, structure of fibrin and cells, and release of TGF-β1 were assessed using thromboelastography (TEG), scanning electron microscopy (SEM), and enzyme-linked immunosobent assay, respectively. Statistical analysis was conducted using the Kruskal Wallis and Mann-Whitney U tests, followed by the post hoc Dunn test. A p value < 0.05 indicated statistical significance. Results: The blood samples in BN_0.5 and BN₃ did not clot, whereas the TEG of BN_5.25 showed altered clot formation. Samples from the CG and BN₃ groups could only be processed with SEM, which showed that the latter lacked fibrin formation and branching of fibers, as well as clumping of red blood cells with surface roughening and distortion. TGF-β1 release was significantly highest in BN₃ when all groups were compared to CG (p < 0.05). Conclusions: Each concentration of NaOCl affected the release of TGF-β1 from blood clots and altered the clotting mechanism of blood by affecting clotting kinetics and cell structure.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.3
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• pp.589-602
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• 2024

Thermoelectric generator (TEG) generally do not have high heat conversion efficiencies. The performance of a thermoelectric generator module depends on the shape of the legs as well as the properties of the material and the number of legs. In this study, the leg shapes of thermoelectric elements are modeled into various geometric structures such as cylinder and cube shaped to efficiently harvest waste heat, and the electrical characteristics are compared numerically. The temperature gradient and power generation according to the bridge shape are found to be highest at the existing Cube shape. As a result of comparing the power generation using the cooling effect, the Cone shape was the highest in natural convection and the Hourglass shape was highest in forced convection. Research results confirm that geometry can affect the efficiency of thermoelectric generators.