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Article ; Online: Large Eddy Simulation of Leakage Flow in a Stepped Labyrinth Seal

Ji-Hwan Kim / Joon Ahn

Processes, Vol 9, Iss 2179, p

2021 Volume 2179

Abstract: Large eddy simulation (LES) and Reynolds averaged Navier-Stokes simulation (RANS) of leakage flow in straight-through and stepped labyrinth seals were performed in order to compare their performances in sealing the secondary flow passage of the gas ... ...

Abstract	Large eddy simulation (LES) and Reynolds averaged Navier-Stokes simulation (RANS) of leakage flow in straight-through and stepped labyrinth seals were performed in order to compare their performances in sealing the secondary flow passage of the gas turbine based on the respective discharge coefficients. The results indicate a 17.8% higher leakage prevention performance for the stepped seal relative to that of the straight seal. Further, while the LES predicts an ~7% reduction in the discharge coefficient due to shaft rotation, this effect is underestimated by the RANS. Moreover, the LES correctly predicts a laminarized flow pattern in the clearance, whereas the RANS overestimates the turbulence kinetic energy. In addition, a turbulence kinetic energy spectrum analysis was performed based on the vorticity at selected points in order to identify the flow structure that has a dominant influence on the oscillation of the discharge coefficient. This analysis also enabled identification of the changes in the flow structure due to shaft rotation.
Keywords	gas turbine ; labyrinth seal ; Reynolds averaged Navier-Stokes simulation (RANS) ; large eddy simulation (LES) ; discharge coefficient ; turbulence kinetic energy ; Chemical technology ; TP1-1185 ; Chemistry ; QD1-999
Subject code	532 ; 621
Language	English
Publishing date	2021-12-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Mediating effect of vascular calcification in galectin-3-related mortality in hemodialysis patients

Ji-Hwan Kim / Hye-Mi Noh / Hong Ji Song / Sion Lee / Sung Gyun Kim / Jwa-Kyung Kim

Scientific Reports, Vol 14, Iss 1, Pp 1-

2024 Volume 10

Abstract: Abstract Galectin-3 levels have been studied as a potential biomarker for predicting cardiovascular (CV) risk and mortality in hemodialysis (HD) patients. Recently, a close relationship between galectin-3 and vascular calcification (VC) has been reported. ...

Abstract	Abstract Galectin-3 levels have been studied as a potential biomarker for predicting cardiovascular (CV) risk and mortality in hemodialysis (HD) patients. Recently, a close relationship between galectin-3 and vascular calcification (VC) has been reported. Here, we investigated the role of VC as a mediating factor in the association between galectin-3 and mortality. Serum galectin-3 and baseline aortic arch calcification (AoAC) score were measured in 477 incident HD patients. Mortality data were obtained at a median follow-up of 40 months. Causal mediation analysis was performed to examine the effect of vascular risk factors on galectin-3-related mortality. The prevalence of AoAC in HD patients was 57% (n = 272), and elevated galectin-3 levels were associated with a significantly increased risk of AoAC. When the galectin-3 level was divided by the median level of 37 ng/mL, a higher galectin group increased the risk of all-cause mortality by 1.71-fold (95% CI 1.02–2.92, p = 0.048), even after adjustment for multiple CV risk factors. Mediation analysis showed that both the direct effect of the galectin-3 on mortality (β = 0.0368, bootstrapped 95% CI [0.0113–0.0622]) and the indirect effects were significant. AoAC score and high-sensitivity CRP levels significantly mediated the association between galectin-3 and mortality (total indirect effects: β = 0.0188, bootstrapped 95% CI [0.0066–0.0352]). This study suggests that the association between high galectin-3 and mortality may be partially mediated by higher VC and inflammatory state in HD patients.
Keywords	Medicine ; R ; Science ; Q
Subject code	610 ; 310
Language	English
Publishing date	2024-01-01T00:00:00Z
Publisher	Nature Portfolio
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: A Machine Learning Approach for Recommending Herbal Formulae with Enhanced Interpretability and Applicability

Won-Yung Lee / Youngseop Lee / Siwoo Lee / Young Woo Kim / Ji-Hwan Kim

Biomolecules, Vol 12, Iss 1604, p

2022 Volume 1604

Abstract: Herbal formulae (HFs) are representative interventions in Korean medicine (KM) for the prevention and treatment of various diseases. Here, we proposed a machine learning-based approach for HF recommendation with enhanced interpretability and ... ...

Abstract	Herbal formulae (HFs) are representative interventions in Korean medicine (KM) for the prevention and treatment of various diseases. Here, we proposed a machine learning-based approach for HF recommendation with enhanced interpretability and applicability. A dataset consisting of clinical symptoms, Sasang constitution (SC) types, and prescribed HFs was derived from a multicenter study. Case studies published over 10 years were collected and curated by experts. Various classifiers, oversampling methods, and data imputation techniques were comprehensively considered. The local interpretable model-agnostic explanation (LIME) technique was applied to identify the clinical symptoms that led to the recommendation of specific HFs. We found that the cascaded deep forest (CDF) model with data imputation and oversampling yielded the best performance on the training set and holdout test set. Our model also achieved top-1 and top-3 accuracies of 0.35 and 0.89, respectively, on case study datasets in which clinical symptoms were only partially recorded. We performed an expert evaluation on the reliability of interpretation results using case studies and achieved a score close to normal. Taken together, our model will contribute to the modernization of KM and the identification of an HF selection process through the development of a practically useful HF recommendation model.
Keywords	herbal formula ; Korean medicine ; recommendation model ; LIME ; Microbiology ; QR1-502
Subject code	006
Language	English
Publishing date	2022-10-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Exploratory Analysis of the Sasang Constitution by Combining Network Analysis and Information Entropy

Won-Yung Lee / Sang Hyuk Kim / Siwoo Lee / Young Woo Kim / Ji-Hwan Kim

Healthcare, Vol 10, Iss 2248, p

2022 Volume 2248

Abstract: Sasang constitutional medicine is a unique concept in Korean medicine that can provide valuable insights into personalized healthcare and disease treatment. In this study, we combined network analysis and information entropy to systematically investigate ...

Abstract	Sasang constitutional medicine is a unique concept in Korean medicine that can provide valuable insights into personalized healthcare and disease treatment. In this study, we combined network analysis and information entropy to systematically investigate the related information of Sasang constitutional (SC) types. A feature network was constructed using SC type and clinical information. The SC type-associated features and feature classes were identified using statistical analysis and entropy ranking. The patient network was constructed based on SC-type-associated features. We found that the feature network was closely connected within the features of the same classes and between several feature class pairs, including the symptom class. Most of the separation values between the feature classes, including the symptom class, were negative. In addition, we found 42 clinical features related to the SC type, and two important classes -personality and cold/heat- that increase the entropy ranking of the SC type. In the patient network, we found sparsely connected modules between SC types and a positive separation value between the Taeeumin–Soeumin and Taeeumin–Soyangin pairs. Our data-driven approach provides a deeper understanding of modernized forms of SC types and suggests that SC type is a practically useful concept for stratified healthcare and personalized medicine.
Keywords	Sasang constitutional medicine ; network-based analytics ; entropy ; personalized medicine ; Medicine ; R
Subject code	410
Language	English
Publishing date	2022-11-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: 3-(5-Hydroxyphenyl)-5-Phenyl-2-Pyrazolines as Toll-Like Receptor 7 Agonists

Ji Hwan Kim / Seunghyun Ahn / Dongsoo Koh / Young Han Lee / Yoongho Lim / Soon Young Shin

Journal of Chemistry, Vol

2023 Volume 2023

Abstract: Toll-like receptor 7 (TLR7) is an attractive target for developing immune modulators to enhance innate immunity against ssRNA virus infections, including hepatitis C and COVID-19. Ten 3-(5-hydroxyphenyl)-5-phenyl-2-pyrazolines were tested using TLR7 ... ...

Abstract	Toll-like receptor 7 (TLR7) is an attractive target for developing immune modulators to enhance innate immunity against ssRNA virus infections, including hepatitis C and COVID-19. Ten 3-(5-hydroxyphenyl)-5-phenyl-2-pyrazolines were tested using TLR7 reporter cells, overexpressing TLR7 and the NF-κB-inducible SEAP reporter gene to discover a novel TLR7 agonist enhancing innate immunity. Of these, 2-(3-(2-hydroxynaphthalen-1-yl)-5-(4-methoxyphenyl)-4,5-dihydro-1H-pyrazol-1-yl)thiazol-4(5H)-one (compound 6) showed the best TLR7 agonistic activity, and further experiments were carried out to study the immune-modulatory capability of compound 6. Treatment with compound 6 rapidly induced phosphorylation of IRAK4, IKKα/β, IκBα, and p65/RelA in THP1 monocytic cells. In addition, it increased the expression of NF-κB-regulated innate cytokines, such as TNFα and IL1β, in THP1 monocytic cells. These data suggest that compound 6 induces an innate immune response by agonizing TLR7 activity in THP1 human monocytic cells. Therefore, compound 6 can be used as an innate immune modulator to develop antiviral agents and vaccine adjuvants.
Keywords	Chemistry ; QD1-999
Language	English
Publishing date	2023-01-01T00:00:00Z
Publisher	Hindawi Limited
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Solvothermal synthesis-driven quaternary Ni-rich cathode for stability-improved Li-ion batteries

Sung-Beom Kim / So-Yeon Ahn / Ji-Hwan Kim / Jae-Sung Jang / Kyung-Won Park

Electrochemistry Communications, Vol 146, Iss , Pp 107426- (2023)

2023

Abstract: Recently, Ni-rich ternary transition metal oxides (Li(NiCoMn)O2, NCM) containing more than 80% Ni have been extensively studied as high-capacity cathodes. Herein, we synthesized a quaternary cathode, Ni-rich Al-doped NCM, using a facile solvothermal ... ...

Abstract	Recently, Ni-rich ternary transition metal oxides (Li(NiCoMn)O2, NCM) containing more than 80% Ni have been extensively studied as high-capacity cathodes. Herein, we synthesized a quaternary cathode, Ni-rich Al-doped NCM, using a facile solvothermal method without an additional Al doping process. Compared to an undoped NCM cathode, the quaternary Ni-rich cathode exhibited improved lithium-ion battery performance (retentions of 82.0% and 65.8% after 100 and 250 cycles, respectively). In particular, the superior stability of the quaternary Ni-rich cathode may result from the stable cathode structure resulting from Al doping.
Keywords	Lithium-ion batteries ; Quaternary Ni-rich cathode ; Aluminum doping ; Solvothermal synthesis ; Industrial electrochemistry ; TP250-261 ; Chemistry ; QD1-999
Language	English
Publishing date	2023-01-01T00:00:00Z
Publisher	Elsevier
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Investigating the Biomarkers of the Sasang Constitution via Network Pharmacology Approach

Won-Yung Lee / Choong-Yeol Lee / Chang-Eop Kim / Ji-Hwan Kim

Evidence-Based Complementary and Alternative Medicine, Vol

2021 Volume 2021

Abstract: Sasang constitutional (SC) medicine classifies people into Soeum (SE), Soyang (SY), Taeeum (TE), and Taeyang (TY) types based on psychological and physical traits. However, biomarkers of these types are still unclear. We aimed to identify biomarkers ... ...

Abstract	Sasang constitutional (SC) medicine classifies people into Soeum (SE), Soyang (SY), Taeeum (TE), and Taeyang (TY) types based on psychological and physical traits. However, biomarkers of these types are still unclear. We aimed to identify biomarkers among the SC types using network pharmacology methods. Target genes associated with the SC types were identified by grouping herb targets that preserve and strengthen the requisite energy (Bomyeongjiju). The herb targets were obtained by constructing an herb-compound-target network. We identified 371, 185, 146, and 89 target genes and their unique biological processes related to SE, SY, TE, and TY types, respectively. While the targets of SE and SY types were the most similar among the target pairs of the SC types, those of TY type overlapped with only a few other SC-type targets. Moreover, SE, SY, TE, and TY were related to “diseases of the digestive system,” “diseases of the nervous system,” “endocrine, nutritional, and metabolic diseases,” and “congenital malformations, deformations, and chromosomal abnormalities,” respectively. We successfully identified the target genes, biological processes, and diseases related to each SC type. We also demonstrated that a drug-centric approach using network pharmacology analysis provides a deeper understanding of the concept of Sasang constitutional medicine at a phenotypic level.
Keywords	Other systems of medicine ; RZ201-999
Language	English
Publishing date	2021-01-01T00:00:00Z
Publisher	Hindawi Limited
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Gender differences in under-reporting hiring discrimination in Korea

Jaehong Yoon / Ji-Hwan Kim / Yeonseung Chung / Jinsu Park / Glorian Sorensen / Seung-Sup Kim

Epidemiology and Health, Vol

a machine learning approach

2021 Volume 43

Abstract: OBJECTIVES This study was conducted to examine gender differences in under-reporting hiring discrimination by building a prediction model for workers who responded “not applicable (NA)” to a question about hiring discrimination despite being eligible to ... ...

Abstract	OBJECTIVES This study was conducted to examine gender differences in under-reporting hiring discrimination by building a prediction model for workers who responded “not applicable (NA)” to a question about hiring discrimination despite being eligible to answer. METHODS Using data from 3,576 wage workers in the seventh wave (2004) of the Korea Labor and Income Panel Study, we trained and tested 9 machine learning algorithms using “yes” or “no” responses regarding the lifetime experience of hiring discrimination. We then applied the best-performing model to estimate the prevalence of experiencing hiring discrimination among those who answered “NA.” Under-reporting of hiring discrimination was calculated by comparing the prevalence of hiring discrimination between the “yes” or “no” group and the “NA” group. RESULTS Based on the predictions from the random forest model, we found that 58.8% of the “NA” group were predicted to have experienced hiring discrimination, while 19.7% of the “yes” or “no” group reported hiring discrimination. Among the “NA” group, the predicted prevalence of hiring discrimination for men and women was 45.3% and 84.8%, respectively. CONCLUSIONS This study introduces a methodological strategy for epidemiologic studies to address the under-reporting of discrimination by applying machine learning algorithms.
Keywords	social discrimination ; social epidemiology ; machine learning ; Medicine ; R
Subject code	332
Language	English
Publishing date	2021-11-01T00:00:00Z
Publisher	Korean Society of Epidemiology
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Hierarchical Phoneme Classification for Improved Speech Recognition

Donghoon Oh / Jeong-Sik Park / Ji-Hwan Kim / Gil-Jin Jang

Applied Sciences, Vol 11, Iss 428, p

2021 Volume 428

Abstract: Speech recognition consists of converting input sound into a sequence of phonemes, then finding text for the input using language models. Therefore, phoneme classification performance is a critical factor for the successful implementation of a speech ... ...

Abstract	Speech recognition consists of converting input sound into a sequence of phonemes, then finding text for the input using language models. Therefore, phoneme classification performance is a critical factor for the successful implementation of a speech recognition system. However, correctly distinguishing phonemes with similar characteristics is still a challenging problem even for state-of-the-art classification methods, and the classification errors are hard to be recovered in the subsequent language processing steps. This paper proposes a hierarchical phoneme clustering method to exploit more suitable recognition models to different phonemes. The phonemes of the TIMIT database are carefully analyzed using a confusion matrix from a baseline speech recognition model. Using automatic phoneme clustering results, a set of phoneme classification models optimized for the generated phoneme groups is constructed and integrated into a hierarchical phoneme classification method. According to the results of a number of phoneme classification experiments, the proposed hierarchical phoneme group models improved performance over the baseline by 3%, 2.1%, 6.0%, and 2.2% for fricative, affricate, stop, and nasal sounds, respectively. The average accuracy was 69.5% and 71.7% for the baseline and proposed hierarchical models, showing a 2.2% overall improvement.
Keywords	speech recognition ; phoneme classification ; clustering ; recurrent neural networks ; Technology ; T ; Engineering (General). Civil engineering (General) ; TA1-2040 ; Biology (General) ; QH301-705.5 ; Physics ; QC1-999 ; Chemistry ; QD1-999
Subject code	006
Language	English
Publishing date	2021-01-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Effect of Fly Ash on Compressive Strength, Drying Shrinkage, and Carbonation Depth of Mortar with Ferronickel-Slag Powder

Se-Jin Choi / Ji-Hwan Kim / Sung-Ho Bae / Tae-Gue Oh

Applied Sciences, Vol 11, Iss 3, p

2021 Volume 1037

Abstract: In recent years, efforts to reduce greenhouse gas emissions have continued worldwide. In the construction industry, a large amount of CO 2 is generated during the production of Portland cement, and various studies are being conducted to reduce the amount ...

Abstract	In recent years, efforts to reduce greenhouse gas emissions have continued worldwide. In the construction industry, a large amount of CO 2 is generated during the production of Portland cement, and various studies are being conducted to reduce the amount of cement and enable the use of cement substitutes. Ferronickel slag is a by-product generated by melting materials such as nickel ore and bituminous coal, which are used as raw materials to produce ferronickel at high temperatures. In this study, we investigated the fluidity, microhydration heat, compressive strength, drying shrinkage, and carbonation characteristics of a ternary cement mortar including ferronickel-slag powder and fly ash. According to the test results, the microhydration heat of the FA20FN00 sample was slightly higher than that of the FA00FN20 sample. The 28-day compressive strength of the FA20FN00 mix was approximately 39.6 MPa, which was higher than that of the other samples, whereas the compressive strength of the FA05FN15 mix including 15% of ferronickel-slag powder was approximately 11.6% lower than that of the FA20FN00 mix. The drying shrinkage of the FA20FN00 sample without ferronickel-slag powder was the highest after 56 days, whereas the FA00FN20 sample without fly ash showed the lowest shrinkage compared to the other mixes.
Keywords	fly ash ; ferronickel slag ; microhydration heat ; compressive strength ; drying shrinkage ; carbonation depth ; Technology ; T ; Engineering (General). Civil engineering (General) ; TA1-2040 ; Biology (General) ; QH301-705.5 ; Physics ; QC1-999 ; Chemistry ; QD1-999
Subject code	660
Language	English
Publishing date	2021-01-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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