14 results on '"CHAE, H."'
Search Results
2. Self-induced parametric amplification arising from nonlinear elastic coupling in a micromechanical resonating disk gyroscope
- Author
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Nitzan, Sarah H., primary, Zega, Valentina, additional, Li, Mo, additional, Ahn, Chae H., additional, Corigliano, Alberto, additional, Kenny, Thomas W., additional, and Horsley, David A., additional
- Published
- 2015
- Full Text
- View/download PDF
3. Correction: Corrigendum: Quantum Limit of Quality Factor in Silicon Micro and Nano Mechanical Resonators
- Author
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Ghaffari, Shirin, primary, Chandorkar, Saurabh A., additional, Wang, Shasha, additional, Ng, Eldwin J., additional, Ahn, Chae H., additional, Hong, Vu, additional, Yang, Yushi, additional, and Kenny, Thomas W., additional
- Published
- 2014
- Full Text
- View/download PDF
4. Quantum Limit of Quality Factor in Silicon Micro and Nano Mechanical Resonators
- Author
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Ghaffari, Shirin, primary, Chandorkar, Saurabh A., additional, Wang, Shasha, additional, Ng, Eldwin J., additional, Ahn, Chae H., additional, Hong, Vu, additional, Yang, Yushi, additional, and Kenny, Thomas W., additional
- Published
- 2013
- Full Text
- View/download PDF
5. Dysbiosis of the initial stool microbiota increases the risk of developing necrotizing enterocolitis or feeding intolerance in newborns.
- Author
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Chae H, Kim SY, Kang HM, Im SA, and Youn YA
- Subjects
- Humans, Infant, Newborn, Female, Male, Risk Factors, Gestational Age, Infant, Premature, Meconium microbiology, Enterocolitis, Necrotizing microbiology, Enterocolitis, Necrotizing etiology, Dysbiosis microbiology, Gastrointestinal Microbiome, Feces microbiology
- Abstract
Several perinatal factors influence the intestinal microbiome of newborns during the first days of life, whether during delivery or even in utero. These factors may increase the risk of developing necrotizing enterocolitis (NEC) by causing dysbiosis linked to a NEC-associated microbiota, which may also be associated with other gastrointestinal problems. The objective of our study was to evaluate the potential risks associated with microbial shifts in newborns with gastrointestinal symptoms and identify the intestinal microbiota of neonates at risk for NEC.During the study period, 310 preterm and term newborns' first passed meconium occurring within 72 h of birth were collected, and the microbiome was analyzed. We identified the risk factors in the NEC/FI group. Regarding microbiota, we compared the bacterial abundance between the NEC/FI group at the phylum and genus levels and explored the differences in the microbial composition of the 1st stool samples. A total of 14.8% (n = 46) of the infants were diagnosed with NEC or FI. In univariate analysis, the mean gestational age and birth weight were significantly lower in the NEC/FI group (p < 0.001). Prolonged rupture of membranes (PROM) > 18 h, chorioamnionitis, and histology were significantly higher in the NEC/FI group (p < 0.001). Multivariate analysis showed that gestational age (GA), prolonged membrane rupture (> 18 h), and early onset sepsis were consistently associated with an increased risk of NEC/FI. Infants diagnosed with NEC/FI exhibited a significantly lower abundance of Actinobacteria at the phylum level than the control group (p < 0.001). At the genus level, a significantly lower abundance of Streptococcus and Bifidobacterium which belong to the Actinobacteria phylum, was observed in the NEC/FI group (p < 0.001). Furthermore, the NEC/FI had significantly lower alpha diversities (Shannon Index,3.39 vs. 3.12; P = 0.044, respectively). Our study revealed that newborns with lower diversity and dysbiosis in their initial gut microbiota had an increased risk of developing NEC, with microbiota differences appearing to be associated with NEC/FI. Dysbiosis could potentially serve as a predictive marker for NEC- or GI-related symptoms., (© 2024. The Author(s).)
- Published
- 2024
- Full Text
- View/download PDF
6. Impact of graphical display on the intention to undergo risk-reducing salpingo-oophorectomy and mastectomy in individuals positive for BRCA pathogenic variant.
- Author
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Choi YJ, Park Y, Park B, Chae H, Jung SY, Ryu KH, Lim MC, Park SJ, Chang YJ, and Kong SY
- Subjects
- Humans, Female, Adult, Middle Aged, BRCA2 Protein genetics, Genetic Predisposition to Disease, Risk Reduction Behavior, Intention, Salpingo-oophorectomy, Breast Neoplasms genetics, Breast Neoplasms surgery, Breast Neoplasms psychology, Breast Neoplasms prevention & control, Ovarian Neoplasms genetics, Ovarian Neoplasms prevention & control, Ovarian Neoplasms surgery, Ovarian Neoplasms psychology, BRCA1 Protein genetics, Mastectomy psychology
- Abstract
The BRCA1/2 pathogenic variant (PV) increases the risk of breast and ovarian cancer; thus, risk-reducing salpingo-oophorectomy (RRSO) and mastectomy (RRM) are recommended. We evaluated the effects of the graphical display of cancer risk compared with those of numerical presentation on the decision-making for risk-reducing (RR) surgery. A total of 471 women representing the Korean population were recruited. The lifetime risk of breast/ovarian cancer were given numerically followed by graphically in hypothetical BRCA1/2 PV-positive cases. Subsequently, the study participants were asked for their willingness to undergo RRSO/RRM. When the ovarian cancer risk was shown as 44.0%, the percentage of study participants who chose RRSO was 41.0% after numerical presentation versus 39.9% after graphical display, of which the difference was not significant. When the breast cancer risk was presented as 72.0%, 30.4% of the participants opted for RRM under numerical presentation, whereas this increased to 38.6% under graphical display, of which the difference was significant (p < 0.0075). The average levels of the cancer risk which study participants consider RR surgery were 57.1% for ovarian cancer and 60.6% for breast cancer. This suggests that the impacts of different formats of risk communication on decision about RRSO or RRM may be different by the absolute levels of ovarian or breast cancer., (© 2024. The Author(s).)
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- 2024
- Full Text
- View/download PDF
7. Efficacy of memory protocols in 9- to 89-year-olds' memory for prior contacts.
- Author
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Goldfarb D, Chae H, Dawson HR, Evans JR, Fisher RP, Daneshbodi A, and Meissner CA
- Subjects
- Child, Humans, Aged, Mental Recall, Memory, Episodic
- Abstract
Memory for prior contacts has several important applied implications, including contact tracing (for communicable diseases). Incomplete episodic memory reports, which occur across the developmental lifespan but are particularly relevant for children and older adults, may hamper such efforts. Prior research has shown that cognitively informed memory techniques may bolster recall of contacts in adults, but that work has not addressed the developmental efficacy of these techniques. Here we evaluated the effectiveness of such techniques for familiar and unfamiliar contacts within a sample of 9- to 89-year-olds in the context of an ongoing pandemic. The tested memory techniques bolstered recall across the lifespan, irrespective of whether the interview was conducted live with an interviewer or via a self-led interview. Children, emerging adults, and adults did not reveal any differences in memory productivity, however, older adults recalled fewer contacts. Implications for theory and application are discussed., (© 2024. The Author(s).)
- Published
- 2024
- Full Text
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8. Simple and practical methods for utilizing parylene C film based on vertical deposition and laser patterning.
- Author
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Sim JH, Chae H, Kim SB, and Yoo S
- Subjects
- Lasers, Polymers, Xylenes
- Abstract
We propose two novel methods to effectively utilize parylene C films. First, we demonstrate a vertical deposition method capable of depositing a parylene C film of the same thickness on both sides of a sample. Through this method, we have formed parylene C films with a thickness of 4 μm on both sides of the sample with a thickness deviation of less than 2.5%. Further optical verification indicates that parylene C films formed by this method have a very uniform thickness distribution on each side of the surfaces. Second, we propose a debris-tolerant laser patterning method as a mask-less means to fabricate self-supporting ultrathin parylene C films. This method does not involve any photolithography and entails a simple and rapid process that can be performed using only a few materials with excellent biocompatibility. It is demonstrated that patterned parylene C films exhibit a high degree of surface uniformity and have various geometrical shapes so that they can be used for substrates of highly flexible and/or stretchable devices. Finally, we use both of the proposed methods to fabricate flexible, stretchable, and waterproof-packaged bifacial blue LED modules to illustrate their potential in emerging applications that would benefit from such versatile form factors., (© 2022. The Author(s).)
- Published
- 2022
- Full Text
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9. Detection method for transparent window cleaning device, image processing approach.
- Author
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Lee J, Chae H, Kim K, Kim HS, and Seo T
- Abstract
Recent years, there has been an increase in the number of high-rise buildings, and subsequently, the interest in external wall cleaning methods has similarly increased. While a number of exterior wall cleaning robots are being developed, a method to detect contaminants on the exterior walls is still required. The exteriors of most high-rise buildings today take the form of a window curtain-wall made of translucent glass. Detecting dust on translucent glass is a significant challenge. Here, we have attempted to overcome this challenge using image processing, inspired by the fact that people typically use just the 'naked eye' to recognize dust on windows. In this paper, we propose a method that detects dust through simple image processing techniques and estimates its density. This method only uses processing techniques that are not significantly restricted by global brightness and background, making it easily applicable in outdoor conditions. Dust separation was performed using a median filter, and dust density was estimated through a mean shift analysis technique. This dust detection method can perform dust separation and density estimation using only an image of the dust on a translucent window with blurry background., (© 2022. The Author(s).)
- Published
- 2022
- Full Text
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10. The factors influencing clinical outcomes after leukapheresis in acute leukaemia.
- Author
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Lee H, Park S, Yoon JH, Cho BS, Kim HJ, Lee S, Kim DW, Chung NG, Cho B, Kim KB, Yoo J, Jekarl DW, Chae H, Lim J, Kim M, Oh EJ, and Kim Y
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, CCAAT-Enhancer-Binding Proteins genetics, Comorbidity, Female, Humans, Leukapheresis standards, Leukemia, Myeloid, Acute epidemiology, Leukemia, Myeloid, Acute genetics, Male, Middle Aged, Mortality trends, Precursor Cell Lymphoblastic Leukemia-Lymphoma epidemiology, Survival Analysis, Leukapheresis statistics & numerical data, Leukemia, Myeloid, Acute therapy, Precursor Cell Lymphoblastic Leukemia-Lymphoma therapy
- Abstract
Leukapheresis is used for the mechanical removal of leukaemic cells in hyperleukocytosis. However, the effectiveness of leukapheresis remains unclear due to selection and confounding factors in the cohorts. We compared the effectiveness of leukapheresis among the subgroups according to either the 2016 World Health Organization classification or the number of cytogenetic abnormalities with a retrospective, single-centre study from January 2009 to December 2018. Acute myeloid leukaemia (AML, n = 212) and acute lymphoblastic leukaemia (ALL, n = 97) were included. The 30-day survival rates (95% confidence interval, 95% CI) for AML and ALL were 86.3% (81.6-90.9%) and 94.8% (90.3-99.2%), respectively. For AML, 'primary AML with myelodysplasia-related changes' and 'AML with biallelic mutation of CEBPA' showed better 30-day survival outcomes (P = 0.026) than the other subgroups. A higher platelet count after leukapheresis was associated with better 30-day survival in AML patients (P = 0.029). A decrease in blast percentage count after leukapheresis was associated with better 30-day survival in ALL patients (P = 0.034). Our study suggested that prophylactic platelet transfusion to raise the platelet count to 50 × 10
9 /L or greater might improve clinical outcome in AML patients undergoing leukapheresis.- Published
- 2021
- Full Text
- View/download PDF
11. Signal amplification by reversible exchange for COVID-19 antiviral drug candidates.
- Author
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Jeong HJ, Min S, Chae H, Kim S, Lee G, Namgoong SK, and Jeong K
- Subjects
- Amides chemistry, Amides pharmacology, Antiviral Agents chemistry, COVID-19, Chloroquine chemistry, Chloroquine pharmacology, Coronavirus Infections diagnosis, Humans, Lopinavir chemistry, Lopinavir pharmacology, Molecular Structure, Nuclear Magnetic Resonance, Biomolecular, Pandemics, Pneumonia, Viral diagnosis, Pyrazines chemistry, Pyrazines pharmacology, Ritonavir chemistry, Ritonavir pharmacology, SARS-CoV-2, Antiviral Agents pharmacology, Betacoronavirus drug effects, Coronavirus Infections virology, Drug Discovery methods, Pneumonia, Viral virology
- Abstract
Several drug candidates have been proposed and tested as the latest clinical treatment for coronavirus pneumonia (COVID-19). Chloroquine, hydroxychloroquine, ritonavir/lopinavir, and favipiravir are under trials for the treatment of this disease. The hyperpolarization technique has the ability to further provide a better understanding of the roles of these drugs at the molecular scale and in different applications in the field of nuclear magnetic resonance/magnetic resonance imaging. This technique may provide new opportunities in diagnosis and research of COVID-19. Signal amplification by reversible exchange-based hyperpolarization studies on large-sized drug candidates were carried out. We observed hyperpolarized proton signals from whole structures, due to the unprecedented long-distance polarization transfer by para-hydrogen. We also found that the optimal magnetic field for the maximum polarization transfer yield was dependent on the molecular structure. We can expect further research on the hyperpolarization of other important large molecules, isotope labeling, as well as polarization transfer on nuclei with a long spin relaxation time. A clinical perspective of these features on drug molecules can broaden the application of hyperpolarization techniques for therapeutic studies.
- Published
- 2020
- Full Text
- View/download PDF
12. Bioinformatic analysis of peripheral blood RNA-sequencing sensitively detects the cause of late graft loss following overt hyperglycemia in pig-to-nonhuman primate islet xenotransplantation.
- Author
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Kim HJ, Moon JH, Chung H, Shin JS, Kim B, Kim JM, Kim JS, Yoon IH, Min BH, Kang SJ, Kim YH, Jo K, Choi J, Chae H, Lee WW, Kim S, and Park CG
- Subjects
- Animals, Computational Biology, Gene Expression Regulation, Graft Rejection blood, Macaca mulatta genetics, Macaca mulatta immunology, Sequence Analysis, RNA, Signal Transduction, T-Lymphocytes immunology, T-Lymphocytes metabolism, Transplantation, Heterologous, Graft Rejection genetics, Hyperglycemia surgery, Islets of Langerhans Transplantation, Macaca mulatta surgery, RNA blood, RNA genetics, Sus scrofa
- Abstract
Clinical islet transplantation has recently been a promising treatment option for intractable type 1 diabetes patients. Although early graft loss has been well studied and controlled, the mechanisms of late graft loss largely remains obscure. Since long-term islet graft survival had not been achieved in islet xenotransplantation, it has been impossible to explore the mechanism of late islet graft loss. Fortunately, recent advances where consistent long-term survival (≥6 months) of adult porcine islet grafts was achieved in five independent, diabetic nonhuman primates (NHPs) enabled us to investigate on the late graft loss. Regardless of the conventional immune monitoring methods applied in the post-transplant period, the initiation of late graft loss could rarely be detected before the overt graft loss observed via uncontrolled blood glucose level. Thus, we retrospectively analyzed the gene expression profiles in 2 rhesus monkey recipients using peripheral blood RNA-sequencing (RNA-seq) data to find out the potential cause(s) of late graft loss. Bioinformatic analyses showed that highly relevant immunological pathways were activated in the animal which experienced late graft failure. Further connectivity analyses revealed that the activation of T cell signaling pathways was the most prominent, suggesting that T cell-mediated graft rejection could be the cause of the late-phase islet loss. Indeed, the porcine islets in the biopsied monkey liver samples were heavily infiltrated with CD3
+ T cells. Furthermore, hypothesis test using a computational experiment reinforced our conclusion. Taken together, we suggest that bioinformatics analyses with peripheral blood RNA-seq could unveil the cause of insidious late islet graft loss.- Published
- 2019
- Full Text
- View/download PDF
13. SQUID-based ultralow-field MRI of a hyperpolarized material using signal amplification by reversible exchange.
- Author
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Lee SJ, Jeong K, Shim JH, Lee HJ, Min S, Chae H, Namgoong SK, and Kim K
- Abstract
The signal amplification by reversible exchange (SABRE) technique is a very promising method for increasing magnetic resonance (MR) signals. SABRE can play a particularly large role in studies with a low or ultralow magnetic field because they suffer from a low signal-to-noise ratio. In this work, we conducted real-time superconducting quantum interference device (SQUID)-based nuclear magnetic resonance (NMR)/magnetic resonance imaging (MRI) studies in a microtesla-range magnetic field using the SABRE technique after designing a bubble-separated phantom. A maximum enhancement of 2658 for
1 H was obtained for pyridine in the SABRE-NMR experiment. A clear SABRE-enhanced MR image of the bubble-separated phantom, in which the para-hydrogen gas was bubbling at only the margin, was successfully obtained at 34.3 μT. The results show that SABRE can be successfully incorporated into an ultralow-field MRI system, which enables new SQUID-based MRI applications. SABRE can shorten the MRI operation time by more than 6 orders of magnitude and establish a firm basis for future low-field MRI applications.- Published
- 2019
- Full Text
- View/download PDF
14. Spatial evolutionary public goods game on complete graph and dense complex networks.
- Author
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Kim J, Chae H, Yook SH, and Kim Y
- Subjects
- Altruism, Cooperative Behavior, Ethics, Humans, Game Theory, Models, Statistical
- Abstract
We study the spatial evolutionary public goods game (SEPGG) with voluntary or optional participation on a complete graph (CG) and on dense networks. Based on analyses of the SEPGG rate equation on finite CG, we find that SEPGG has two stable states depending on the value of multiplication factor r, illustrating how the "tragedy of the commons" and "an anomalous state without any active participants" occurs in real-life situations. When r is low (<<), the state with only loners is stable, and the state with only defectors is stable when r is high (>>). We also derive the exact scaling relation for r*. All of the results are confirmed by numerical simulation. Furthermore, we find that a cooperator-dominant state emerges when the number of participants or the mean degree, 〈k〉, decreases. We also investigate the scaling dependence of the emergence of cooperation on r and 〈k〉. These results show how "tragedy of the commons" disappears when cooperation between egoistic individuals without any additional socioeconomic punishment increases.
- Published
- 2015
- Full Text
- View/download PDF
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