29 results on '"Cho, B"'
Search Results
2. Parametric excitation and mode control using an Oersted field in a NiFe nanowire
- Author
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Hwang, S., Yoon, Seungha, Seo, Dongpyo, Han, S. H., and Cho, B. K.
- Published
- 2021
- Full Text
- View/download PDF
3. Quadrupolar ordering and exotic magnetocaloric effect in RB4 (R = Dy, Ho)
- Author
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Song, M. S., Cho, K. K., Kang, B. Y., Lee, S. B., and Cho, B. K.
- Published
- 2020
- Full Text
- View/download PDF
4. Current-induced magnetic switching with spin-orbit torque in an interlayer-coupled junction with a Ta spacer layer
- Author
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Kwak, W.-Y., primary, Kwon, J.-H., additional, Grünberg, P., additional, Han, S. H., additional, and Cho, B. K., additional
- Published
- 2018
- Full Text
- View/download PDF
5. Matching DMFT calculations with photoemission spectra of heavy fermion insulators: universal properties of the near-gap spectra of SmB6
- Author
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Min, Chul-Hee, primary, Goth, F., additional, Lutz, P., additional, Bentmann, H., additional, Kang, B. Y., additional, Cho, B. K., additional, Werner, J., additional, Chen, K.-S., additional, Assaad, F., additional, and Reinert, F., additional
- Published
- 2017
- Full Text
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6. Field-driven dynamics and time-resolved measurement of Dzyaloshinskii-Moriya torque in canted antiferromagnet YFeO3
- Author
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Kim, Tae Heon, primary, Grüenberg, Peter, additional, Han, S. H., additional, and Cho, B. K., additional
- Published
- 2017
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- View/download PDF
7. Measurement of Electron-Ion Relaxation in Warm Dense Copper
- Author
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Cho, B. I., primary, Ogitsu, T., additional, Engelhorn, K., additional, Correa, A. A., additional, Ping, Y., additional, Lee, J. W., additional, Bae, L. J., additional, Prendergast, D., additional, Falcone, R. W., additional, and Heimann, P. A., additional
- Published
- 2016
- Full Text
- View/download PDF
8. Study of spin-ordering and spin-reorientation transitions in hexagonal manganites through Raman spectroscopy
- Author
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Chen, Xiang-Bai, primary, Hien, Nguyen Thi Minh, additional, Han, Kiok, additional, Nam, Ji-Yeon, additional, Huyen, Nguyen Thi, additional, Shin, Seong-Il, additional, Wang, Xueyun, additional, Cheong, S. W., additional, Lee, D., additional, Noh, T. W., additional, Sung, N. H., additional, Cho, B. K., additional, and Yang, In-Sang, additional
- Published
- 2015
- Full Text
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9. Evidence for a glassy state in strongly driven carbon
- Author
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Brown, C. R. D., primary, Gericke, D. O., additional, Cammarata, M., additional, Cho, B. I., additional, Döppner, T., additional, Engelhorn, K., additional, Förster, E., additional, Fortmann, C., additional, Fritz, D., additional, Galtier, E., additional, Glenzer, S. H., additional, Harmand, M., additional, Heimann, P., additional, Kugland, N. L., additional, Lamb, D. Q., additional, Lee, H. J., additional, Lee, R. W., additional, Lemke, H., additional, Makita, M., additional, Moinard, A., additional, Murphy, C. D., additional, Nagler, B., additional, Neumayer, P., additional, Plagemann, K.-U., additional, Redmer, R., additional, Riley, D., additional, Rosmej, F. B., additional, Sperling, P., additional, Toleikis, S., additional, Vinko, S. M., additional, Vorberger, J., additional, White, S., additional, White, T. G., additional, Wünsch, K., additional, Zastrau, U., additional, Zhu, D., additional, Tschentscher, T., additional, and Gregori, G., additional
- Published
- 2014
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10. Towards simultaneous measurements of electronic and structural properties in ultra-fast x-ray free electron laser absorption spectroscopy experiments
- Author
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Gaudin, J., primary, Fourment, C., additional, Cho, B. I., additional, Engelhorn, K., additional, Galtier, E., additional, Harmand, M., additional, Leguay, P. M., additional, Lee, H. J., additional, Nagler, B., additional, Nakatsutsumi, M., additional, Ozkan, C., additional, Störmer, M., additional, Toleikis, S., additional, Tschentscher, Th, additional, Heimann, P. A., additional, and Dorchies, F., additional
- Published
- 2014
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11. A genome-wide by PM 10 exposure interaction study for blood pressure in Korean adults.
- Author
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Kim HJ, Son HY, Park P, Yun JM, Kwon H, Cho B, Kim JI, and Park JH
- Subjects
- Humans, Adult, Blood Pressure genetics, Genetic Predisposition to Disease, Genotype, Particulate Matter adverse effects, Particulate Matter analysis, Republic of Korea, Polymorphism, Single Nucleotide, Environmental Exposure adverse effects, Environmental Exposure analysis, Air Pollutants analysis, Air Pollution analysis
- Abstract
Blood pressure (BP) is a typical complex trait, and the genetic susceptibility of individuals to changes in BP induced by air pollution exposure is different. Although interactions of exposure to air pollutants with several candidate genes have been identified, genome-wide interaction studies (GWISs) are needed to understand the association between them with BP. Therefore, we aimed to discover the unique genetic loci for BP that interact with exposure to air pollutants in Korean adults. We ultimately included 1868 participants in the discovery step and classified them into groups of those with low-to-moderate exposure and high exposure to average annual concentration of particulate matter with an aerodynamic diameter ≤ 10 μm (PM
10 ). Because none of the single nucleotide polymorphisms (SNPs) achieved a genome-wide level of significance of pint < 5 × 10-8 for either systolic BP (SBP) or diastolic BP (DBP), we considered the top 10 ranking SNPs for each BP trait. To validate these suggestive SNPs, we finally selected six genetic variants for SBP and five variants for DBP, respectively. In a replication result for SBP, only one SNP (rs12914147) located in an intergenic region of the NR2F2 showed a significant interaction. We also identified several genetic susceptibility loci (e.g., CHST11, TEK, and ITGA1) implicated in candidate mechanisms such as inflammation and oxidative stress in the discovery step, although their interaction effects were not replicated. Our study reports the first GWIS finding to our knowledge, and the association between exposure to PM10 and BP levels may be determined in part by several newly discovered genetic suggestive loci, including NR2F2., (© 2023. Springer Nature Limited.)- Published
- 2023
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12. Association of underweight status with the risk of tuberculosis: a nationwide population-based cohort study.
- Author
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Cho SH, Lee H, Kwon H, Shin DW, Joh HK, Han K, Park JH, and Cho B
- Subjects
- Body Mass Index, Cohort Studies, Humans, Overweight epidemiology, Risk Factors, Thinness complications, Thinness epidemiology, Tuberculosis complications, Tuberculosis epidemiology
- Abstract
In studies evaluating the association between body mass index (BMI) and risk of tuberculosis (TB), the data for the underweight population has been limited and results were conflicting. Our study aimed to evaluate whether being underweight increases the risk of TB using a nationwide representative sample from the Republic of Korea. A large population-based cohort study of over ten million subjects who participated in the health screening in 2010 was performed using the Korean National Health Insurance database 2010-2017. We evaluated the incidence and risk of TB by BMI category (kg/m
2 ) for Asians using a multivariable Cox regression model, adjusting for age, sex, smoking, alcohol consumption, regular exercise, low-income state, and underlying hypertension, diabetes mellitus, and dyslipidemia. To evaluate the association between BMI and TB risk, the underweight population was further subdivided according to the degree of thinness. During 70,063,154.3 person-years of follow-up, 52,615 of 11,135,332 individuals developed active TB with an incidence of 0.75 per 1000 person-years. Overall, there was a log-linear inverse relationship between TB incidence and BMI, within the BMI range of 15-30 kg/m2 (R2 = 0.95). The estimated adjusted hazard ratio (HR) for incident TB in the underweight population (BMI < 18.5) was 2.08 (95% confidence intervals, CI 2.02-2.15), overweight (23 ≤ BMI < 25) was 0.56 (0.55-0.58) and obese (BMI ≥ 25) was 0.40 (0.39-0.41) relative to the normal weight population. Among the underweight population, TB risk increased as the degree of thinness increased (adjusted HR = 1.98, 1.91-2.05; 2.50, 2.33-2.68; and 2.83, 2.55-3.15, for mild, moderate and severe thinness, respectively) (p for trend < 0.001). We found a significant inverse relationship between BMI and TB incidence, which was especially profound in the underweight population. Public health strategies to screen TB more actively in the underweight population and improve their weight status may help reduce the burden of TB., (© 2022. The Author(s).)- Published
- 2022
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13. Exceptional properties of hyper-resistant armor of a hydrothermal vent crab.
- Author
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Cho B, Kim D, and Kim T
- Subjects
- Adaptation, Physiological, Animals, Indian Ocean, Seafood, Brachyura, Hydrothermal Vents
- Abstract
Animals living in extreme environments, such as hydrothermal vents, would be expected to have evolved protective shells or exoskeletons to maintain homeostasis. The outer part of the exoskeleton of vent crabs (Austinograea sp.) in the Indian Ocean hydrothermal vent was one of the hardest (approximately 7 GPa) biological materials ever reported. To explore the exoskeletal characteristics of vent crabs which enable them to adapt to severe environments, a comparative analysis was conducted with the Asian paddle crab (Charybdis japonica) living in coastal areas. Nanoindentation, thermogravimetric analysis, scanning electron microscopy, energy dispersive x-ray analysis, and Raman spectroscopy were used to analyze the mechanical properties, thermal stability, structure, surface components, and the composition of compounds, respectively. Though both species have four-layered exoskeletons, the outermost layer of the vent crab, a nano-granular structure, was much thicker than that of the coastal crab. The proportions of aluminum and sulfur that constitute the epicuticle of the exoskeleton were higher in the vent crab than in the coastal crab. There was a lack of water or volatile substances, lots of CaCO
3 , and no carotenoid-based compounds in the exoskeleton of the vent crab. These might have improved the mechanical properties and thermal stability of the hydrothermal species., (© 2022. The Author(s).)- Published
- 2022
- Full Text
- View/download PDF
14. Association of metabolic syndrome with mobility in the older adults: a Korean nationwide representative cross-sectional study.
- Author
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Son KY, Shin DW, Lee JE, Kim SH, Yun JM, and Cho B
- Subjects
- Adult, Aged, Female, Geriatric Assessment statistics & numerical data, Humans, Male, Middle Aged, Movement, Republic of Korea, Metabolic Syndrome epidemiology, Mobility Limitation
- Abstract
We aimed to examine whether metabolic syndrome (MetS) is associated with mobility in the older adults, using the timed up and go (TUG) test which is one of the most widely used tests for evaluating mobility. This is population-based study with the National Health Insurance Service-National Health Screening Cohort database of National Health Information Database. Participants included were those who completed the TUG as part of the National Screening Program for Transitional Ages. An abnormal TUG result was defined as a time ≥ 10 s. Multiple logistic regression models were used to assess the associations between MetS and TUG results. We constructed three models with different levels of adjustment. Furthermore, we conducted a stratified analysis according to the risk. Among the 40,767 participants included, 19,831 (48.6%) were women. Mean TUG value was 8.34 ± 3.07 s, and abnormal TUG test results were observed in 4,391 (10.8%) participants; 6,888 (16.9%) participants were categorised to have MetS. The worst TUG test results were obtained in participants with three or four MetS features, and a J-shaped relationship of each MetS feature, except triglyceride (TG) and high-density lipoprotein-cholesterol (HDL-C), with TUG test was found. Participants with MetS had 18% higher likelihood of showing abnormal TUG test results in a fully adjusted model (adjusted odds ratio 1.183, 95% confidence interval 1.115-1.254). The stratified analysis revealed that participants with central obesity, high blood pressure, and normal HDL-C and TG were more likely to have abnormal TUG times. Participants with MetS had a higher risk of exhibiting abnormal TUG results, and except for HDL-C and TG, all other MetS features had a J-shaped relationship with TUG. Preventive lifestyle such as lower carbohydrate and higher protein intake, and endurance exercise is needed.
- Published
- 2021
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15. 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
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16. The effect of smoking on chronic inflammation, immune function and blood cell composition.
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Elisia I, Lam V, Cho B, Hay M, Li MY, Yeung M, Bu L, Jia W, Norton N, Lam S, and Krystal G
- Subjects
- Aged, Blood Cell Count, C-Reactive Protein analysis, Carcinoembryonic Antigen blood, Chronic Disease, Female, Fibrinogen analysis, Humans, Inflammation pathology, Interleukin-6 blood, Male, Middle Aged, Adaptive Immunity immunology, Biomarkers blood, Cytokines blood, Immunity, Innate immunology, Inflammation blood, Smoking
- Abstract
Smoking is the number one risk factor for cancer mortality but only 15-20% of heavy smokers develop lung cancer. It would, therefore, be of great benefit to identify those at high risk early on so that preventative measures can be initiated. To investigate this, we evaluated the effects of smoking on inflammatory markers, innate and adaptive immune responses to bacterial and viral challenges and blood cell composition. We found that plasma samples from 30 heavy smokers (16 men and 14 women) had significantly higher CRP, fibrinogen, IL-6 and CEA levels than 36 non-smoking controls. Whole blood samples from smokers, incubated for 7 h at 37 °C in the absence of any exogenous stimuli, secreted significantly higher levels of IL-8 and a number of other cytokines/chemokines than non-smokers. When challenged for 7 h with E. coli, whole blood samples from smokers secreted significantly lower levels of many inflammatory cytokines/chemokines. However, when stimulated with HSV-1, significantly higher levels of both PGE
2 and many cytokines/chemokines were secreted from smokers' blood samples than from controls. In terms of blood cell composition, red blood cells, hematocrits, hemoglobin levels, MCV, MCH, MCHC, Pct and RDW levels were all elevated in smokers, in keeping with their compromised lung capacity. As well, total leukocytes were significantly higher, driven by increases in granulocytes and monocytes. In addition, smokers had lower NK cells and higher Tregs than controls, suggesting that smoking may reduce the ability to kill nascent tumor cells. Importantly, there was substantial person-to person variation amongst smokers with some showing markedly different values from controls and others showing normal levels of many parameters measured, indicating the former may be at significantly higher risk of developing lung cancer.- Published
- 2020
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17. Clinical implementation of a wide-field electron arc technique with a scatterer for widespread Kaposi's sarcoma in the distal extremities.
- Author
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Kim SW, Kim C, Cho MS, Noh S, Lee M, Jeong C, Kwak J, Koh M, Song SY, Lee SW, Soh J, Cho S, and Cho B
- Subjects
- Foot, Hand, Humans, Monte Carlo Method, Phantoms, Imaging, Radiotherapy Dosage, Radiotherapy Planning, Computer-Assisted, Proton Therapy methods, Sarcoma, Kaposi radiotherapy, Skin Neoplasms radiotherapy
- Abstract
A novel wide-field electron arc technique with a scatterer is implemented for widespread Kaposi's sarcoma (KS) in the distal extremities. Monte Carlo beam modeling for electron arc beams was established to achieve <2% deviation from the measurements, and used for dose calculation. MC-based electron arc plan was performed using CT images of a foot and leg mimicking phantom and compared with in-vivo measurement data. We enrolled one patient with recurrent KS on the lower extremities who had been treated with photon radiation therapy. The 4- and 6-MeV electron arc plans were created, and then compared to two photon plans: two opposite photon beam and volumetric modulated arc with bolus. Compared to the two photon techniques, the electron arc plans resulted in superior dose saving to normal organs beneath the skin region, although it shows inferior coverage and homogeneity for PTV. The electron arc treatment technique with scatterer was successfully implemented for the treatment of widespread KS in the distal extremities with lower radiation exposure to the normal organs beyond the skin lesions, which could be a treatment option for recurrent skin cancer in the extremities.
- Published
- 2020
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18. Abdominal multi-organ auto-segmentation using 3D-patch-based deep convolutional neural network.
- Author
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Kim H, Jung J, Kim J, Cho B, Kwak J, Jang JY, Lee SW, Lee JG, and Yoon SM
- Subjects
- Adult, Aged, Aged, 80 and over, Algorithms, Duodenum diagnostic imaging, Female, Humans, Imaging, Three-Dimensional methods, Kidney diagnostic imaging, Liver diagnostic imaging, Male, Middle Aged, Stomach diagnostic imaging, Abdomen diagnostic imaging, Liver Neoplasms diagnostic imaging, Neural Networks, Computer, Tomography, X-Ray Computed methods
- Abstract
Segmentation of normal organs is a critical and time-consuming process in radiotherapy. Auto-segmentation of abdominal organs has been made possible by the advent of the convolutional neural network. We utilized the U-Net, a 3D-patch-based convolutional neural network, and added graph-cut algorithm-based post-processing. The inputs were 3D-patch-based CT images consisting of 64 × 64 × 64 voxels designed to produce 3D multi-label semantic images representing the liver, stomach, duodenum, and right/left kidneys. The datasets for training, validating, and testing consisted of 80, 20, and 20 CT simulation scans, respectively. For accuracy assessment, the predicted structures were compared with those produced from the atlas-based method and inter-observer segmentation using the Dice similarity coefficient, Hausdorff distance, and mean surface distance. The efficiency was quantified by measuring the time elapsed for segmentation with or without automation using the U-Net. The U-Net-based auto-segmentation outperformed the atlas-based auto-segmentation in all abdominal structures, and showed comparable results to the inter-observer segmentations especially for liver and kidney. The average segmentation time without automation was 22.6 minutes, which was reduced to 7.1 minutes with automation using the U-Net. Our proposed auto-segmentation framework using the 3D-patch-based U-Net for abdominal multi-organs demonstrated potential clinical usefulness in terms of accuracy and time-efficiency.
- Published
- 2020
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19. Adolescent overweight and obesity and the risk of papillary thyroid cancer in adulthood: a large-scale case-control study.
- Author
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Kim KN, Hwang Y, Kim KH, Lee KE, Park YJ, Kim SJ, Kwon H, Park DJ, Cho B, Choi HC, Kang D, and Park SK
- Subjects
- Adolescent, Age Factors, Body Mass Index, Body Weight Maintenance, Case-Control Studies, Humans, Middle Aged, Pediatric Obesity prevention & control, Risk, Pediatric Obesity complications, Thyroid Cancer, Papillary etiology, Thyroid Neoplasms etiology
- Abstract
This study aimed to investigate the association between adolescent overweight and obesity and PTC risk in adulthood. We conducted a case-control study in the Republic of Korea with 1,549 PTC patients and 15,490 controls individually matched for age and sex. We estimated body mass index (BMI) at age 18 years from self-reported weight at this age. Compared with BMI < 23.0 at age 18 years, BMI ≥ 25.0 at age 18 years was associated with higher PTC risk (odds ratio [OR] = 4.31, 95% confidence interval [CI]: 3.57, 5.22). The association between BMI ≥ 25.0 at age 18 years and PTC risk was stronger among men (OR = 6.65, 95% CI: 4.78, 9.27) than among women (OR = 3.49, 95% CI: 2.74, 4.43), and stronger among individuals with current BMI ≥ 25.0 (OR = 8.21, 95% CI: 6.34, 10.62) than among those with current BMI < 25.0 (OR = 2.21, 95% CI: 1.49, 3.27). Among PTC patients, BMI ≥ 25.0 at age 18 years was associated with extra-thyroidal extension and T stage ≥2, but not with N stage ≥1 or BRAF
V600E mutation. Adolescent overweight and obesity was associated with higher risk of PTC in adulthood. Our results emphasise the importance of weight management in adolescence to decrease the PTC risk.- Published
- 2020
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20. Predicting the Effects of Random Ocean Dynamic Processes on Underwater Acoustic Sensing and Communication.
- Author
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Cho B and Makris NC
- Abstract
Acoustics is the primary means of sensing and communication in the ocean for humans and many marine animals. Natural fluctuations in the ocean, however, degrade these abilities in ways that have been previously difficult to forecast. Here, we address this issue by predicting sensing and communication degradation in terms of acoustic attenuation, dispersion and temporal decorrelation at typical operational ranges and frequencies in continental-shelf environments. This is done with analytic expressions derived from first physical principles. The analytic expressions provide the statistics of the acoustic field after forward propagating through an ocean waveguide containing 3-D random inhomogeneities from the independent or combined effects of rough sea-surfaces, near-sea-surface air bubbles and internal waves. The formulation also includes Doppler effects caused by the inhomogeneities' random horizontal motion, enabling modeling and prediction over a wide range of environments and frequencies. Theoretical predictions are confirmed with available acoustic measurements in several continental-shelf environments using standard oceanographic measurements for environmental support. We quantify how the acoustic signals decorrelate over timescales determined by the underlying temporal coherence of ocean dynamic processes. Surface gravity waves and near-sea-surface air bubbles decorrelate acoustic signals over seconds or less, whereas internal waves affect acoustic coherence at timescales of several to tens of minutes. Doppler spread caused by the inhomogeneities' motion further reduces acoustic temporal coherence, and becomes important at the high frequencies necessary for communication and fine-scale sensing. We also show that surface gravity waves and bubbles in high sea states can cause increasingly significant attenuation as frequency increases. The typical durations of marine mammal vocalizations that carry over great distances are found to be consistent with the coherence timescales quantified here and so avoid random distortion of signal information even by incoherent reception.
- Published
- 2020
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- View/download PDF
21. Fluence-map generation for prostate intensity-modulated radiotherapy planning using a deep-neural-network.
- Author
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Lee H, Kim H, Kwak J, Kim YS, Lee SW, Cho S, and Cho B
- Subjects
- Algorithms, Humans, Male, Neural Networks, Computer, Prostate diagnostic imaging, Prostate pathology, Prostatic Neoplasms diagnostic imaging, Prostatic Neoplasms pathology, Radiotherapy Dosage, Prostate radiation effects, Prostatic Neoplasms radiotherapy, Radiotherapy Planning, Computer-Assisted, Radiotherapy, Intensity-Modulated
- Abstract
A deep-neural-network (DNN) was successfully used to predict clinically-acceptable dose distributions from organ contours for intensity-modulated radiotherapy (IMRT). To provide the next step in the DNN-based plan automation, we propose a DNN that directly generates beam fluence maps from the organ contours and volumetric dose distributions, without inverse planning. We collected 240 prostate IMRT plans and used to train a DNN using organ contours and dose distributions. After training was done, we made 45 synthetic plans (SPs) using the generated fluence-maps and compared them with clinical plans (CP) using various plan quality metrics including homogeneity and conformity indices for the target and dose constraints for organs at risk, including rectum, bladder, and bowel. The network was able to generate fluence maps with small errors. The qualities of the SPs were comparable to the corresponding CPs. The homogeneity index of the target was slightly worse in the SPs, but there was no difference in conformity index of the target, V
60Gy of rectum, the V60Gy of bladder and the V45Gy of bowel. The time taken for generating fluence maps and qualities of SPs demonstrated the proposed method will improve efficiency of the treatment planning and help maintain the quality of plans.- Published
- 2019
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22. Effects of a hypomagnetic field on DNA methylation during the differentiation of embryonic stem cells.
- Author
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Baek S, Choi H, Park H, Cho B, Kim S, and Kim J
- Subjects
- Animals, Epigenesis, Genetic, Gene Expression Regulation, Developmental genetics, Humans, Mice, Mouse Embryonic Stem Cells metabolism, Pluripotent Stem Cells cytology, Pluripotent Stem Cells metabolism, DNA Methyltransferase 3B, Cell Differentiation genetics, DNA (Cytosine-5-)-Methyltransferases genetics, DNA Methylation genetics, Mouse Embryonic Stem Cells cytology
- Abstract
It has been reported that hypomagnetic fields (HMFs) have a negative influence on mammalian physiological functions. We previously reported that HMFs were detrimental to cell fate changes during reprogramming into pluripotency. These studies led us to investigate whether HMFs affect cell fate determination during direct differentiation. Here, we found that an HMF environment attenuates differentiation capacity and is detrimental to cell fate changes during the in vitro differentiation of embryonic stem cells (ESCs). Moreover, HMF conditions cause abnormal DNA methylation through the dysregulation of DNA methyltransferase3b (Dnmt3b) expression, eventually resulting in incomplete DNA methylation during differentiation. Taken together, these results suggest that an appropriate electromagnetic field (EMF) environment may be essential for favorable epigenetic remodeling during cell fate determination via differentiation.
- Published
- 2019
- Full Text
- View/download PDF
23. Evaluation of Hepatic Toxicity after Repeated Stereotactic Body Radiation Therapy for Recurrent Hepatocellular Carcinoma using Deformable Image Registration.
- Author
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Lee S, Kim H, Ji Y, Cho B, Kim SS, Jung J, Kwak J, Park JH, Lee SW, Kim JH, and Yoon SM
- Subjects
- Aged, Carcinoma, Hepatocellular diagnosis, Female, Humans, Liver pathology, Liver radiation effects, Liver Neoplasms diagnosis, Male, Middle Aged, Radiation Injuries etiology, Radiosurgery methods, Radiotherapy Dosage, Retreatment, Tomography, X-Ray Computed, Treatment Outcome, Tumor Burden, Carcinoma, Hepatocellular complications, Carcinoma, Hepatocellular radiotherapy, Liver Neoplasms complications, Liver Neoplasms radiotherapy, Radiosurgery adverse effects, Radiotherapy, Image-Guided adverse effects, Radiotherapy, Image-Guided methods
- Abstract
This study aimed to evaluate hepatic toxicity after repeated stereotactic body radiation therapy (SBRT) for recurrent hepatocellular carcinoma (HCC) using deformable image registration (DIR). Between January 2007 and December 2015, 85 patients who underwent two sessions of SBRT for HCC treatment were retrospectively analyzed. A DIR technique was used to calculate the cumulative dose of the first and second SBRT to the normal liver by matching two computed tomography simulation images. The Dice similarity coefficient (DSC) index was calculated to evaluate DIR accuracy. Before the first and second SBRT, 6 (7.1%) and 12 (14.1%) patients were Child-Pugh class B, respectively. Median tumor size was 1.7 cm before both SBRT treatments. Mean DSC index value was 0.93, being >0.9 in 79 (92.9%) registrations. Median cumulative mean liver dose (MLD) was 9.3 Gy (interquartile range, 7.6-11.7). Radiation-induced liver disease developed in three patients, and two of them, with Child-Pugh class B, experienced irreversible liver function deterioration following the second SBRT. The DIR method provided reliable information regarding cumulative doses to the liver. In patients with Child-Pugh class A liver function, repeated SBRT for small recurrent HCC could be safely performed with acceptable hepatic toxicity.
- Published
- 2018
- Full Text
- View/download PDF
24. Ultrafast spin dynamics and switching via spin transfer torque in antiferromagnets with weak ferromagnetism.
- Author
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Kim TH, Grünberg P, Han SH, and Cho B
- Abstract
The spin-torque driven dynamics of antiferromagnets with Dzyaloshinskii-Moriya interaction (DMI) were investigated based on the Landau-Lifshitz-Gilbert-Slonczewski equation with antiferromagnetic and ferromagnetic order parameters (l and m, respectively). We demonstrate that antiferromagnets including DMI can be described by a 2-dimensional pendulum model of l. Because m is coupled with l, together with DMI and exchange energy, close examination of m provides fundamental understanding of its dynamics in linear and nonlinear regimes. Furthermore, we discuss magnetization reversal as a function of DMI and anisotropy energy induced by a spin current pulse.
- Published
- 2016
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25. Controlled Growth of Rubrene Nanowires by Eutectic Melt Crystallization.
- Author
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Chung J, Hyon J, Park KS, Cho B, Baek J, Kim J, Lee SU, Sung MM, and Kang Y
- Abstract
Organic semiconductors including rubrene, Alq3, copper phthalocyanine and pentacene are crystallized by the eutectic melt crystallization. Those organic semiconductors form good eutectic systems with the various volatile crystallizable additives such as benzoic acid, salicylic acid, naphthalene and 1,3,5-trichlorobenzene. Due to the formation of the eutectic system, organic semiconductors having originally high melting point (Tm > 300 °C) are melted and crystallized at low temperature (Te = 40.8-133 °C). The volatile crystallizable additives are easily removed by sublimation. For a model system using rubrene, single crystalline rubrene nanowires are prepared by the eutectic melt crystallization and the eutectic-melt-assisted nanoimpinting (EMAN) technique. It is demonstrated that crystal structure and the growth direction of rubrene can be controlled by using different volatile crystallizable additives. The field effect mobility of rubrene nanowires prepared using several different crystallizable additives are measured and compared.
- Published
- 2016
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26. Measurement of the Nucleus Area and Nucleus/Cytoplasm and Mitochondria/Nucleus Ratios in Human Colon Tissues by Dual-Colour Two-Photon Microscopy Imaging.
- Author
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Su Lim C, Sun Kim E, Yeon Kim J, Taek Hong S, Jai Chun H, Eun Kang D, and Rae Cho B
- Subjects
- Colonic Neoplasms diagnosis, DNA metabolism, Diagnostic Imaging methods, Fluorescent Dyes chemistry, Fluorescent Dyes metabolism, HeLa Cells, Humans, Molecular Structure, Reproducibility of Results, Sensitivity and Specificity, Spectrometry, Fluorescence methods, Cell Nucleus metabolism, Colon metabolism, Colonic Neoplasms metabolism, Cytoplasm metabolism, Microscopy, Fluorescence, Multiphoton methods, Mitochondria metabolism
- Abstract
We developed two-photon (TP) probes for DNA (ABI-Nu), cytoplasm (Pyr-CT), and mitochondria (BF-MT). We found that ABI-Nu binds to AT in the minor groove, while ABI-Nu and BF-MT are effective for tracking in the cytoplasm and mitochondria, respectively. These probes showed very large effective two-photon action cross section values of 2230, 1555, and 790 Göppert-Mayer units (1 GM = 10(-50) cm(4) s photon(-1) molecule(-1)) at 740 nm with emission maxima at 473, 561, and 560 nm, respectively, in each organelle. Using these probes, we quantitatively estimated the mean nuclear area and the ratios of nuclei to cytoplasm and mitochondria to nuclei in human colon tissues by dual-colour two-photon microscopy imaging within 2 h after biopsy. The mean nuclear area and the nuclei to cytoplasm and mitochondria to cytoplasm ratios increased in the following order: normal colon mucosa
- Published
- 2015
- Full Text
- View/download PDF
27. Dynamin-related protein 1 controls the migration and neuronal differentiation of subventricular zone-derived neural progenitor cells.
- Author
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Kim HJ, Shaker MR, Cho B, Cho HM, Kim H, Kim JY, and Sun W
- Subjects
- Animals, Carnitine pharmacology, Cell Differentiation drug effects, Cell Movement drug effects, Cell Polarity, Cells, Cultured, Lateral Ventricles cytology, Male, Membrane Potential, Mitochondrial drug effects, Mice, Mice, Inbred C57BL, Microscopy, Fluorescence, Mitochondria metabolism, Neural Stem Cells metabolism, Oligomycins pharmacology, Quinazolinones pharmacology, Dynamins metabolism, Neural Stem Cells cytology
- Abstract
Mitochondria are important in many essential cellular functions, including energy production, calcium homeostasis, and apoptosis. The organelles are scattered throughout the cytoplasm, but their distribution can be altered in response to local energy demands, such as cell division and neuronal maturation. Mitochondrial distribution is closely associated with mitochondrial fission, and blocking the fission-promoting protein dynamin-related protein 1 (Drp1) activity often results in mitochondrial elongation and clustering. In this study, we observed that mitochondria were preferentially localized at the leading process of migratory adult neural stem cells (aNSCs), whereas neuronal differentiating cells transiently exhibited perinuclear condensation of mitochondria. Inhibiting Drp1 activity altered the typical migratory cell morphology into round shapes while the polarized mitochondrial distribution was maintained. With these changes, aNSCs failed to migrate, and neuronal differentiation was prevented. Because Drp1 blocking also impaired the mitochondrial membrane potential, we tested whether supplementing with L-carnitine, a compound that restores mitochondrial membrane potential and ATP synthesis, could revert the defects induced by Drp1 inhibition. Interestingly, L-carnitine fully restored the aNSC defects, including cell shrinkage, migration, and impaired neuronal differentiation. These results suggest that Drp1 is required for functionally active mitochondria, and supplementing with ATP can restore the defects induced by Drp1 suppression.
- Published
- 2015
- Full Text
- View/download PDF
28. Charge-transfer-based gas sensing using atomic-layer MoS2.
- Author
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Cho B, Hahm MG, Choi M, Yoon J, Kim AR, Lee YJ, Park SG, Kwon JD, Kim CS, Song M, Jeong Y, Nam KS, Lee S, Yoo TJ, Kang CG, Lee BH, Ko HC, Ajayan PM, and Kim DH
- Abstract
Two-dimensional (2D) molybdenum disulphide (MoS2) atomic layers have a strong potential to be used as 2D electronic sensor components. However, intrinsic synthesis challenges have made this task difficult. In addition, the detection mechanisms for gas molecules are not fully understood. Here, we report a high-performance gas sensor constructed using atomic-layered MoS2 synthesised by chemical vapour deposition (CVD). A highly sensitive and selective gas sensor based on the CVD-synthesised MoS2 was developed. In situ photoluminescence characterisation revealed the charge transfer mechanism between the gas molecules and MoS2, which was validated by theoretical calculations. First-principles density functional theory calculations indicated that NO2 and NH3 molecules have negative adsorption energies (i.e., the adsorption processes are exothermic). Thus, NO2 and NH3 molecules are likely to adsorb onto the surface of the MoS2. The in situ PL characterisation of the changes in the peaks corresponding to charged trions and neutral excitons via gas adsorption processes was used to elucidate the mechanisms of charge transfer between the MoS2 and the gas molecules.
- Published
- 2015
- Full Text
- View/download PDF
29. Ultrasmooth, extremely deformable and shape recoverable Ag nanowire embedded transparent electrode.
- Author
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Nam S, Song M, Kim DH, Cho B, Lee HM, Kwon JD, Park SG, Nam KS, Jeong Y, Kwon SH, Park YC, Jin SH, Kang JW, Jo S, and Kim CS
- Abstract
Transparent electrodes have been widely used in electronic devices such as solar cells, displays, and touch screens. Highly flexible transparent electrodes are especially desired for the development of next generation flexible electronic devices. Although indium tin oxide (ITO) is the most commonly used material for the fabrication of transparent electrodes, its brittleness and growing cost limit its utility for flexible electronic devices. Therefore, the need for new transparent conductive materials with superior mechanical properties is clear and urgent. Ag nanowire (AgNW) has been attracting increasing attention because of its effective combination of electrical and optical properties. However, it still suffers from several drawbacks, including large surface roughness, instability against oxidation and moisture, and poor adhesion to substrates. These issues need to be addressed before wide spread use of metallic NW as transparent electrodes can be realized. In this study, we demonstrated the fabrication of a flexible transparent electrode with superior mechanical, electrical and optical properties by embedding a AgNW film into a transparent polymer matrix. This technique can produce electrodes with an ultrasmooth and extremely deformable transparent electrode that have sheet resistance and transmittance comparable to those of an ITO electrode.
- Published
- 2014
- Full Text
- View/download PDF
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