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Beigtan M, Gonçalves M, Weon BM. Heat Transfer by Sweat Droplet Evaporation. Environ Sci Technol 2024; 58:6532-6539. [PMID: 38538556 PMCID: PMC11025549 DOI: 10.1021/acs.est.4c00850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 03/03/2024] [Accepted: 03/12/2024] [Indexed: 04/17/2024]
Abstract
Sweating regulates the body temperature in extreme environments or during exercise. Here, we investigate the evaporative heat transfer of a sweat droplet at the microscale to unveil how the evaporation complexity of a sweat droplet would affect the body's ability to cool under specific environmental conditions. Our findings reveal that, depending on the relative humidity and temperature levels, sweat droplets experience imperfect evaporation dynamics, whereas water droplets evaporate perfectly at equivalent ambient conditions. At low humidity, the sweat droplet fully evaporates and leaves a solid deposit, while at high humidity, the droplet never reaches a solid deposit and maintains a liquid phase residue for both low and high temperatures. This unprecedented evaporation mechanism of a sweat droplet is attributed to the intricate physicochemical properties of sweat as a biofluid. We suppose that the sweat residue deposited on the surface by evaporation is continuously absorbing the surrounding moisture. This route leads to reduced evaporative heat transfer, increased heat index, and potential impairment of the body's thermoregulation capacity. The insights into the evaporative heat transfer dynamics at the microscale would help us to improve the knowledge of the body's natural cooling mechanism with practical applications in healthcare, materials science, and sports science.
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Affiliation(s)
- Mohadese Beigtan
- Soft
Matter Physics Laboratory, School of Advanced Materials Science and
Engineering, Sungkyunkwan University, Suwon 16419, South Korea
| | - Marta Gonçalves
- Soft
Matter Physics Laboratory, School of Advanced Materials Science and
Engineering, Sungkyunkwan University, Suwon 16419, South Korea
- Research
Center for Advanced Materials Technology, Sungkyunkwan University, Suwon 16419, South Korea
| | - Byung Mook Weon
- Soft
Matter Physics Laboratory, School of Advanced Materials Science and
Engineering, Sungkyunkwan University, Suwon 16419, South Korea
- Research
Center for Advanced Materials Technology, Sungkyunkwan University, Suwon 16419, South Korea
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2
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Jeong DI, Kang D, Kang BK, Lee UY, Suh IY, Kim Y, Weon BM, Kim SW, Yoon DH. Self-Powered Water Splitting of Ni 3FeN@Fe 24N 10 Bifunctional Catalyst Improved Catalytic Activity and Durability by Forming Fe 24N 10 on Catalyst Surface via the Kirkendall Effect. Small 2024:e2400374. [PMID: 38566523 DOI: 10.1002/smll.202400374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 03/18/2024] [Indexed: 04/04/2024]
Abstract
Highly efficient water splitting electrocatalyst for producing hydrogen as a renewable energy source offers potential to achieve net-zero. However, it has significant challenges in using transition metal electrocatalysts as alternatives to noble metals due to their low efficiency and durability, furthermore, the reliance on electricity generation for electrocatalysts from fossil fuels leads to unavoidable carbon emissions. Here, a highly efficient self-powered water splitting system integrated is designed with triboelectric nanogenerator (TENG) and Ni3FeN@Fe24N10 catalyst with improved catalytic activity and durability. First, the durability of the Ni3FeN catalyst is improved by forming N, P carbon shell using melamine, polyetherimide, and phytic acid. The catalyst activity is improved by generating Fe24N10 in the carbon shell through the Kirkendall effect. The synthesized Ni3FeN@Fe24N10 catalyst exhibited excellent bifunctional catalytic activity (ηOER = 261.8 mV and ηHER = 151.8 mV) and remarkable stability (91.7% in OER and 90.5% in HER) in 1 m KOH. Furthermore, to achieve ecofriendly electricity generation, a rotation-mode TENG that sustainably generate high-performance is realized using butylated melamine formaldehyde. As a result, H2 is successfully generated using the integrated system composed of the designed TENG and catalyst. The finding provides a promising approach for energy generation to achieve net-zero.
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Affiliation(s)
- Dong In Jeong
- School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Donghyeon Kang
- School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Bong Kyun Kang
- Department of Electronic Materials, Devices, and Equipment Engineering, Soonchunhyang University, Chungnam, 31538, Republic of Korea
- Advanced Energy Research Center, Soonchunhyang University, Chungnam, 31538, Republic of Korea
| | - Ui Young Lee
- School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - In-Yong Suh
- School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Yeseul Kim
- School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Byung Mook Weon
- School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Sang-Woo Kim
- Department of Materials Science and Engineering, Center for Human-oriented Triboelectric Energy Harvesting, Yonsei University, Seoul, 03722, Republic of Korea
| | - Dae Ho Yoon
- School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
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3
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Brito S, Heo H, Cha B, Lee SH, Park G, Kwak BM, Seong JK, Lee H, Park JH, Weon BM, Bin BH. The Slc45a4 Gene Regulates Pigmentation in a Manner Distinct from that of the OCA4 Gene Slc45a2. J Invest Dermatol 2024; 144:720-722.e5. [PMID: 37775036 DOI: 10.1016/j.jid.2023.08.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 08/07/2023] [Accepted: 08/15/2023] [Indexed: 10/01/2023]
Affiliation(s)
- Sofia Brito
- School of Advanced Materials Science & Engineering, Sungkyunkwan University, Suwon, Republic of Korea; Research Center for Advanced Materials Technology, Sungkyunkwan University, Suwon, Republic of Korea
| | - Hyojin Heo
- Department of Applied Bio Technology, Graduate School, Ajou University, Suwon, Republic of Korea
| | - Byungsun Cha
- Department of Biological Sciences, Graduate School, Ajou University, Suwon, Republic of Korea
| | - Sang Hun Lee
- Department of Biological Sciences, Graduate School, Ajou University, Suwon, Republic of Korea
| | - Gunwoo Park
- Department of Applied Bio Technology, Graduate School, Ajou University, Suwon, Republic of Korea; Korea Bioinformation Center, Korea Research Institute of Bioscience & Biotechnology, Daejeon, Republic of Korea
| | - Byeong-Mun Kwak
- Department of Biological Sciences, Graduate School, Ajou University, Suwon, Republic of Korea
| | - Je Kyung Seong
- Laboratory of Developmental Biology and Genomics, BK21 Plus Program for Advanced Veterinary Science, Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea; Interdiscplinary Program for Bioinformatics, Seoul National University, Seoul, Republic of Korea; Korea Mouse Phenotyping Center, Seoul National University, Seoul, Republic of Korea
| | - Ho Lee
- Korea Mouse Phenotyping Center, Seoul National University, Seoul, Republic of Korea; Graduate School of Cancer Science and Policy, National Cancer Center, Goyang, Republic of Korea
| | - Ji-Hwan Park
- Korea Bioinformation Center, Korea Research Institute of Bioscience & Biotechnology, Daejeon, Republic of Korea
| | - Byung Mook Weon
- School of Advanced Materials Science & Engineering, Sungkyunkwan University, Suwon, Republic of Korea; Research Center for Advanced Materials Technology, Sungkyunkwan University, Suwon, Republic of Korea
| | - Bum-Ho Bin
- Department of Applied Bio Technology, Graduate School, Ajou University, Suwon, Republic of Korea; Department of Biological Sciences, Graduate School, Ajou University, Suwon, Republic of Korea.
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4
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Gonçalves M, Weon BM. Evaluating Droplet Survivability on Face Masks with X-ray Microtomography. ACS Appl Bio Mater 2024; 7:193-202. [PMID: 38146923 DOI: 10.1021/acsabm.3c00804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
Abstract
When a person talks, coughs, or sneezes, respiratory droplets are expelled and inevitably land on several surfaces, representing a route for respiratory disease transmission. Here, face masks act as a barrier by obstructing the passage of droplets during exhalation and inhalation. Being constantly exposed to respiratory events and carrying droplet residue, understanding the evaporation and absorption dynamics for tiny droplets on face masks and the fate of viral particle deposition is necessary to analyze the contamination risk. We explore the ideal design for masks from the interaction of mask surfaces with surrogate respiratory droplets by X-ray microscopy and microtomography. We show that the respiratory droplet survivability is significantly reduced in masks with a hydrophilic surface where absorption takes place, leading to a reduction of the postevaporation droplet residue at the mask surface compared with a hydrophobic surface. The results allow us to propose a better mask layer design dependent on wettability, reducing the risk of contamination from respiratory droplets.
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Affiliation(s)
- Marta Gonçalves
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, South Korea
- Research Center for Advanced Materials Technology, Sungkyunkwan University, Suwon 16419, South Korea
| | - Byung Mook Weon
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, South Korea
- Research Center for Advanced Materials Technology, Sungkyunkwan University, Suwon 16419, South Korea
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5
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Choi JS, Doo HM, Kim B, Lee SH, Sung SK, Go G, Suarez A, Kim Y, Weon BM, Choi BO, Kim HJ, Kim DH. NanoIEA: A Nanopatterned Interdigitated Electrode Array-Based Impedance Assay for Real-Time Measurement of Aligned Endothelial Cell Barrier Functions. Adv Healthc Mater 2024; 13:e2301124. [PMID: 37820720 PMCID: PMC10841753 DOI: 10.1002/adhm.202301124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 09/18/2023] [Indexed: 10/13/2023]
Abstract
A nanopatterned interdigitated electrode array (nanoIEA)-based impedance assay is developed for quantitative real-time measurement of aligned endothelial cell (EC) barrier functions in vitro. A bioinspired poly(3,4-dihydroxy-L-phenylalanine) (poly (l-DOPA)) coating is applied to improve the human brain EC adhesion onto the Nafion nanopatterned surfaces. It is found that a poly (l-DOPA)-coated Nafion grooved nanopattern makes the human brain ECs orient along the nanopattern direction. Aligned human brain ECs on Nafion nanopatterns exhibit increased expression of genes encoding tight and adherens junction proteins. Aligned human brain ECs also have enhanced impedance and resistance versus unaligned ones. Treatment with a glycogen synthase kinase-3 inhibitor (GSK3i) further increases impedance and resistance, suggesting synergistic effects occur on the cell-cell tightness of in vitro human brain ECs via a combination of anisotropic matrix nanotopography and GSK3i treatment. It is found that this enhanced cell-cell tightness of the combined approach is accompanied by increased expression of claudin protein. These data demonstrate that the proposed nanoIEA assay integrated with poly (l-DOPA)-coated Nafion nanopatterns and interdigitated electrode arrays can make not only biomimetic aligned ECs, but also enable real-time measurement of the enhanced barrier functions of aligned ECs via tighter cell-cell junctions.
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Affiliation(s)
- Jong Seob Choi
- Department of Biomedical Engineering, Center for Microphysiological Systems, Johns Hopkins University, Baltimore, MD, 21205, USA
- Division of Advanced Materials Engineering, Kongju National University, Cheonan, Chungnam, 31080, South Korea
| | - Hyun Myung Doo
- Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul, 06351, South Korea
- Department of Biomedical Research Center, Korea University Guro Hospital, Seoul, 08308, South Korea
- Division of Medical Oncology, Department of Internal Medicine, Korea University Guro Hospital, Korea University College of Medicine, Seoul, 08308, South Korea
| | - Byunggik Kim
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Su Han Lee
- Digital Health Care Research Center, Gumi Electronics and Information Technology Research Institute (GERI), Gumi, Gyeongbuk, 39253, South Korea
| | - Sang-Keun Sung
- Digital Health Care Research Center, Gumi Electronics and Information Technology Research Institute (GERI), Gumi, Gyeongbuk, 39253, South Korea
| | - Gwangjun Go
- Department of Biomedical Engineering, Center for Microphysiological Systems, Johns Hopkins University, Baltimore, MD, 21205, USA
- Department of Mechanical Engineering, Chosun University, Gwangju, 61452, South Korea
| | - Allister Suarez
- Department of Biomedical Engineering, Center for Microphysiological Systems, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Yeseul Kim
- SKKU Advanced Institute of Nanotechnology (SAINT), School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, 16419, South Korea
| | - Byung Mook Weon
- SKKU Advanced Institute of Nanotechnology (SAINT), School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, 16419, South Korea
| | - Byung-Ok Choi
- Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul, 06351, South Korea
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, 06351, South Korea
| | - Hyung Jin Kim
- School of Electrical and Electronic Engineering, Ulsan College, Ulsan, 44610, South Korea
| | - Deok-Ho Kim
- Department of Biomedical Engineering, Center for Microphysiological Systems, Johns Hopkins University, Baltimore, MD, 21205, USA
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, 21218, USA
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6
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Choi JS, Lee SH, Park HB, Chun C, Kim Y, Kim KH, Weon BM, Kim DH, Kim HJ, Lee JH. The deformation of cancer cells through narrow micropores holds the potential to regulate genes that impact cancer malignancy. Lab Chip 2023; 23:3628-3638. [PMID: 37448298 DOI: 10.1039/d3lc00069a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/15/2023]
Abstract
Surgery, radiation, hormonal therapy, chemotherapy, and immunotherapy are standard treatment strategies for metastatic breast cancer. However, the heterogeneous nature of the disease poses challenges and continues to make it life-threatening. It is crucial to elucidate further the underlying signaling pathways to improve treatment efficacy. Our study established two triple-negative breast cancer cell lines (TW-1 and TW-2) that were physically deformed using 3 μm pores to investigate the relationship between cancer cell deformation and metastasis within a heterogeneous population. The physical transformation of TW-1 and TW-2 cells significantly affected their growth and migration speed, as evidenced by wound healing assays for collective cell migration and microchannel assays for single-cell migration. We conducted bulk RNA sequencing to gain insights into the genes influenced by physical deformation. Additionally, we evaluated the effects of trametinib resistance on breast cancer cell metastasis by assessing cell viability and migration rates. Interestingly, TW-1 and TW-2 cells exhibited resistance to trametinib treatment. We observed a significant upregulation of GABRA-3, a protein commonly expressed in malignant breast cancer, and the critical transcription factor Myc in TW-1 and TW-2 cells compared to the control group (Ori). However, we did not observe a significant difference in Myc expression between TW-1 and TW-2 cells. In contrast, in the trametinib-resistant cell lines (TW-1-Tra and TW-2-Tra), we found increased expression of OCT4 and SOX2 rather than GABRA-3 or Myc. These findings highlight the differential expression patterns of these genes in our study, suggesting their potential role in cancer cell deformation and drug resistance. Our study presents a potential in vitro model for metastatic and drug-resistant breast cancer cells. By investigating the correlation between cancer cell deformation and metastasis, we contribute to understanding breast cancer heterogeneity and lay the groundwork for developing improved treatment strategies.
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Affiliation(s)
- Jong Seob Choi
- Department of Bioengineering, University of Washington, 850 Republican Street, Seattle, WA 98109, USA
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Baltimore, MD, 21205, USA
- Division of Advanced Materials Engineering, Kongju National University, Budaedong 275, Seobuk-gu, Cheonan-si, Chungnam, 31080, South Korea
| | - Su Han Lee
- Digital Health Care Research Center, Gumi Electronics and Information Technology Research Institute (GERI), 350-27, Gumidaero, Gumi, Gyeongbuk 39253, South Korea
| | - Hye Bin Park
- Digital Health Care Research Center, Gumi Electronics and Information Technology Research Institute (GERI), 350-27, Gumidaero, Gumi, Gyeongbuk 39253, South Korea
| | - Changho Chun
- Department of Bioengineering, University of Washington, 850 Republican Street, Seattle, WA 98109, USA
| | - Yeseul Kim
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 16419, South Korea
| | - Kyung Hoon Kim
- Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, WA 98195, USA
| | - Byung Mook Weon
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 16419, South Korea
| | - Deok-Ho Kim
- Department of Bioengineering, University of Washington, 850 Republican Street, Seattle, WA 98109, USA
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Baltimore, MD, 21205, USA
| | - Hyung Jin Kim
- Digital Health Care Research Center, Gumi Electronics and Information Technology Research Institute (GERI), 350-27, Gumidaero, Gumi, Gyeongbuk 39253, South Korea
| | - Jung Hyun Lee
- Division of Dermatology, Department of Medicine, University of Washington, 850 Republican Street, Seattle, WA 98109, USA.
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Seattle, WA 98109, USA
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7
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Beigtan M, Hwang Y, Weon BM. Inhibiting Cracks in Latte Droplets. Langmuir 2023; 39:5275-5283. [PMID: 37026986 DOI: 10.1021/acs.langmuir.2c03183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Latte is a mixture of coffee and milk and a model of complex fluids containing biomolecules, usually leaving complex deposit patterns after droplet evaporation. Despite the universality and applicability of biofluids, their evaporation and deposition dynamics are not fully understood and controllable because of the complexity of their components. Here we investigate latte droplet evaporation and deposition dynamics, primarily the crack development and inhibition in droplet deposit patterns. With regard to a mixture of milk and coffee, we find that the surfactant-like nature of milk and intermolecular interactions between coffee particles and milk bioparticles are responsible for achieving uniform crack-free deposits. This finding improves our understanding of pattern formation from evaporating droplets with complex biofluids, offering a clue to applications of bioinks with both printability and biocompatibility.
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Affiliation(s)
- Mohadese Beigtan
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 16419, South Korea
| | - Yohan Hwang
- College of General Education, Seoul Women's University, Seoul 01797, South Korea
| | - Byung Mook Weon
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 16419, South Korea
- Research Center for Advanced Materials Technology, Sungkyunkwan University, Suwon 16419, South Korea
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8
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Kim MW, Weon BM, Je JH. Spherical alveolar shapes in live mouse lungs. Sci Rep 2023; 13:5319. [PMID: 37002270 PMCID: PMC10066015 DOI: 10.1038/s41598-023-32254-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 03/24/2023] [Indexed: 04/03/2023] Open
Abstract
Understanding how the alveolar mechanics work in live lungs is essential for comprehending how the lung behaves during breathing. Due to the lack of appropriate imaging tools, previous research has suggested that alveolar morphologies are polyhedral rather than spherical based on a 2D examination of alveoli in fixed lungs. Here, we directly observe high-resolution 3D alveoli in live mice lungs utilizing synchrotron x-ray microtomography to show spherical alveolar morphologies from the live lungs. Our measurements from x-ray microtomography show high sphericity, low packing density, big alveolar size, and low osmotic pressure, indicating that spherical alveolar morphologies are natural in living lungs. The alveolar packing fraction is quite low in live lungs, where the spherical alveoli would behave like free bubbles, while the confinement of alveolar clusters in fixed lungs would lead to significant morphological deformations of the alveoli appearing polyhedral. Direct observations of the spherical alveolar shapes will help understand and treat lung disease and ventilation.
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Affiliation(s)
- Min Woo Kim
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, San 31, Hyojadong, Pohang, 37673, South Korea
| | - Byung Mook Weon
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419, South Korea.
- Research Center for Advanced Materials Technology, Core Research Institute, Suwon, 16419, South Korea.
| | - Jung Ho Je
- Department of Materials Science and Engineering, Pohang University of Science and Technology, San 31, Hyoja-Dong, Pohang, 37673, South Korea.
- Nanoblesse Research Lab., Nanoblesse, 4Th Fl. 85-11, Namwon-Ro, Pohang, 37883, South Korea.
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Gonçalves M, Weon BM. Limits to lifespan growth. Front Public Health 2023; 10:1037544. [PMID: 36684960 PMCID: PMC9853412 DOI: 10.3389/fpubh.2022.1037544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 12/15/2022] [Indexed: 01/09/2023] Open
Abstract
A long-standing human lifespan debate is revival, and the consensus is yet to come on whether the maximum human lifespan is reaching a limit or not. This study discusses how mathematical constraints inherent in survival curves indicate a limit on maximum lifespans, implying that humans would have inevitable limits to lifespan growth.
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Affiliation(s)
| | - Byung Mook Weon
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, South Korea
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10
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Kim H, Gonçalves M, Kang SH, Weon BM. High density deposits of binary colloids. Sci Rep 2022; 12:22307. [PMID: 36566318 PMCID: PMC9790000 DOI: 10.1038/s41598-022-26151-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 12/09/2022] [Indexed: 12/25/2022] Open
Abstract
Colloids are essential materials for modern inkjet printing and coating technology. For printing and coating, it is desirable to have a high density of colloids with uniformity. Binary colloids, which consist of different size colloidal particles, have the potential to achieve high coating density and uniformity from size effects. We report a strategy to attain high-density deposits of binary colloids with uniform, crack-free, and symmetric deposits through droplet evaporation on micropillar arrays. We modify surfaces of micropillar arrays with plasma treatment to control their surface energy and investigate how binary colloidal fluids turn into well-controlled deposits during evaporation with X-ray microscopic and tomographic characterizations. We attribute temporary surface energy modification of micropillar arrays to the well-controlled high-density final deposits. This simple, low-cost, and scalable strategy would provide a viable way to get high-quality, high-density deposits of colloids for various applications.
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Affiliation(s)
- Hyoeun Kim
- grid.264381.a0000 0001 2181 989XSoft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419 South Korea ,grid.264381.a0000 0001 2181 989XResearch Center for Advanced Materials Technology, Sungkyunkwan University, Suwon, 16419 South Korea ,grid.21107.350000 0001 2171 9311Department of Mechanical Engineering and Hopkins Extreme Materials Institute, Johns Hopkins University, Baltimore, MD 21218 USA
| | - Marta Gonçalves
- grid.264381.a0000 0001 2181 989XSoft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419 South Korea
| | - Sung Hoon Kang
- grid.21107.350000 0001 2171 9311Department of Mechanical Engineering and Hopkins Extreme Materials Institute, Johns Hopkins University, Baltimore, MD 21218 USA
| | - Byung Mook Weon
- grid.264381.a0000 0001 2181 989XSoft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419 South Korea ,grid.264381.a0000 0001 2181 989XResearch Center for Advanced Materials Technology, Sungkyunkwan University, Suwon, 16419 South Korea
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11
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Yeo SJ, Oh MJ, Kim Y, Weon BM, Kwon SJ, Yoo PJ. Controlled synthesis of solid-shelled non-spherical and faceted microbubbles. Nanoscale 2022; 14:12581-12588. [PMID: 36039694 DOI: 10.1039/d2nr03741f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The ability to control the shape of hollow particles (e.g., capsules or bubbles) holds great promise for enhancing the encapsulation efficiency and mechanical/optical properties. However, conventional preparation methods suffer from a low yield, difficulty in controlling the shape, and a tedious production process, limiting their widespread application. Here, we present a method for fabricating polyhedral graphene oxide (GO)-shelled microbubbles with sharp edges and vertices, which is based on the microfluidic generation of spherical compound bubbles followed by shell deformation. Sphere-to-polytope deformation is a result of the shell instability due to gradual outward gas transport, which is dictated by Laplace pressure across the shell. The shape-variant behaviours of the bubbles can also be attributed to the compositional heterogeneity of the shells. In particular, the high degree of control of microfluidic systems enables the formation of non-spherical bubbles with various shapes; the structural motifs of the bubbles are easily controlled by varying the size and thickness of the mid-shell in compound bubbles, ranging from tetrahedra to octahedra. The strategy presented in this study provides a new route for fabricating 3D structured solid bubbles, which is particularly advantageous for the development of high-performance mechanical or thermal material applications.
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Affiliation(s)
- Seon Ju Yeo
- Department of Nature-Inspired System and Application, Korea Institute of Machinery & Materials (KIMM), Daejeon 34103, Republic of Korea
| | - Min Jun Oh
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Youngsoo Kim
- Department of Nature-Inspired System and Application, Korea Institute of Machinery & Materials (KIMM), Daejeon 34103, Republic of Korea
| | - Byung Mook Weon
- School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Seok Joon Kwon
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea.
- SKKU Institute of Energy Science and Technology (SIEST), Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Pil J Yoo
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea.
- SKKU Institute of Energy Science and Technology (SIEST), Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
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12
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Abstract
Droplet evaporation on porous materials is a complex dynamic that occurs with spontaneous liquid imbibition through pores by capillary action. Here, we explore water dynamics on a porous fabric substrate with in-situ observations of X-ray and optical imaging techniques. We show how spreading and wicking lead to water imbibition through a porous substrate, enhancing the wetted surface area and consequently promoting evaporation. These sequential dynamics offer a framework to understand the alterations in the evaporation due to porosity for the particular case of fabric materials and a clue of how face masks interact with respiratory droplets.
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Affiliation(s)
- Marta Gonçalves
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419, South Korea
| | - Jin Young Kim
- Research Center for Advanced Materials Technology, Sungkyunkwan University, Suwon, 16419, South Korea
| | - Yeseul Kim
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419, South Korea
| | - Najaf Rubab
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419, South Korea
| | - Narina Jung
- Korea Institute for Advanced Study, Seoul, 02455, South Korea
| | - Takeshi Asai
- Faculty of Health and Sports Science, University of Tsukuba, Tsukuba, 305 8574, Japan
| | - Sungchan Hong
- Faculty of Health and Sports Science, University of Tsukuba, Tsukuba, 305 8574, Japan.
| | - Byung Mook Weon
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419, South Korea.
- Research Center for Advanced Materials Technology, Sungkyunkwan University, Suwon, 16419, South Korea.
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13
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Kim Y, Gonçalves M, Kim DH, Weon BM. Topological heterogeneity and evaporation dynamics of irregular water droplets. Sci Rep 2021; 11:18700. [PMID: 34548520 PMCID: PMC8455589 DOI: 10.1038/s41598-021-98115-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 09/03/2021] [Indexed: 11/20/2022] Open
Abstract
Water droplets sitting between wires are ubiquitous in nature and industry, often showing irregular (non-spherical) droplet shapes. To understand their topological singularity and evaporation mechanism, measuring volume changes of irregular water droplets is essential but highly challenging for small-volume water droplets. Here we experimentally explore topological heterogeneity and evaporation dynamics for irregular water droplets between wires with four-dimensional X-ray microtomography that directly provides images in three spatial dimensions as a function of time, enabling us to get three-dimensional structural and geometric information changes with time. We find that the topological heterogeneity of an irregular droplet is due to the local contact lines and the evaporation dynamics of an irregular droplet is governed by the effective contact radius. This study may offer an opportunity to understand how the topological heterogeneity contributes to the evaporation dynamics of irregular water droplets.
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Affiliation(s)
- Yeseul Kim
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419, South Korea
| | - Marta Gonçalves
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419, South Korea
| | - Deok-Ho Kim
- Department of Bioengineering, University of Washington, Seattle, WA, 98195, USA.,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Byung Mook Weon
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419, South Korea. .,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, 21205, USA.
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14
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Abstract
Colloidal droplets on flat solid substrates commonly leave symmetric ring-like deposits due to coffee-ring flows during evaporation. On inclined substrates, droplet shapes may become asymmetric by gravity. On this basis, it is not clear how their evaporation dynamics and final deposits are changed depending on inclination. Here we explore evaporation and deposition dynamics of colloidal droplets on inclined substrates, mainly by controlling colloidal particle size, substrate inclination, and relative humidity, which are crucial to gravitational intervention and evaporation dynamics. We experimentally investigate two different flows with opposite directions: downward sedimentation flows by gravity (\documentclass[12pt]{minimal}
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\begin{document}$$\ll$$\end{document}≪ 1, evaporation-driven upward flows overwhelm sedimentation-driven downward flows, resulting in accentuated particle movement towards the top ring, which seems to defy gravitational intervention. We suggest a possible explanation for the flow speed dependence of final deposits in evaporating colloidal droplets. This study offers a framework to understand the intervention of inclination to the formation of final deposits and how to overcome the deposit pattern radial asymmetry, achieving symmetric deposit widths from inclined colloidal droplets.
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Affiliation(s)
- Jin Young Kim
- Research Center for Advanced Materials Technology, Sungkyunkwan University, Suwon, 16419, South Korea.,Department of Materials, ETH Zürich, 8093, Zurich, Switzerland
| | - Marta Gonçalves
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419, South Korea
| | - Narina Jung
- Research Center for Advanced Materials Technology, Sungkyunkwan University, Suwon, 16419, South Korea
| | - Hyoungsoo Kim
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea.
| | - Byung Mook Weon
- Research Center for Advanced Materials Technology, Sungkyunkwan University, Suwon, 16419, South Korea. .,SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419, South Korea. .,School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, 16419, South Korea.
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15
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Hong SH, Oh H, Park YW, Kwak HW, Oh EY, Park HJ, Kang KW, Kim G, Koo BS, Hwang EH, Baek SH, Park HJ, Lee YS, Bang YJ, Kim JY, Bae SH, Lee SJ, Seo KW, Kim H, Kwon T, Kim JH, Lee S, Kim E, Kim Y, Park JH, Park SI, Gonçalves M, Weon BM, Jeong H, Nam KT, Hwang KA, Kim J, Kim H, Lee SM, Hong JJ, Nam JH. Immunization with RBD-P2 and N protects against SARS-CoV-2 in nonhuman primates. Sci Adv 2021; 7:7/22/eabg7156. [PMID: 34049881 DOI: 10.1126/sciadv.abg7156] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Accepted: 04/09/2021] [Indexed: 06/12/2023]
Abstract
Since the emergence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), various vaccines are being developed, with most vaccine candidates focusing on the viral spike protein. Here, we developed a previously unknown subunit vaccine comprising the receptor binding domain (RBD) of the spike protein fused with the tetanus toxoid epitope P2 (RBD-P2) and tested its efficacy in rodents and nonhuman primates (NHPs). We also investigated whether the SARS-CoV-2 nucleocapsid protein (N) could increase vaccine efficacy. Immunization with N and RBD-P2 (RBDP2/N) + alum increased T cell responses in mice and neutralizing antibody levels in rats compared with those obtained using RBD-P2 + alum. Furthermore, in NHPs, RBD-P2/N + alum induced slightly faster SARS-CoV-2 clearance than that induced by RBD-P2 + alum, albeit without statistical significance. Our study supports further development of RBD-P2 as a vaccine candidate against SARS-CoV-2. Also, it provides insights regarding the use of N in protein-based vaccines against SARS-CoV-2.
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Affiliation(s)
- So-Hee Hong
- Department of Medical and Biological Sciences, The Catholic University of Korea, Bucheon 14662, Republic of Korea
| | - Hanseul Oh
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju, Chungcheongbuk, Republic of Korea
| | - Yong Wook Park
- Department of Research and Development, SK Bioscience, Pangyoro 332, Bundang-gu, Republic of Korea
| | - Hye Won Kwak
- Department of Medical and Biological Sciences, The Catholic University of Korea, Bucheon 14662, Republic of Korea
| | - Eun Young Oh
- Division of Biotechnology, College of Environmental and Bioresources, Jeonbuk National University, Iksan 54596, Republic of Korea
| | - Hyo-Jung Park
- Department of Medical and Biological Sciences, The Catholic University of Korea, Bucheon 14662, Republic of Korea
| | - Kyung Won Kang
- Division of Biotechnology, College of Environmental and Bioresources, Jeonbuk National University, Iksan 54596, Republic of Korea
| | - Green Kim
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju, Chungcheongbuk, Republic of Korea
| | - Bon-Sang Koo
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju, Chungcheongbuk, Republic of Korea
| | - Eun-Ha Hwang
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju, Chungcheongbuk, Republic of Korea
| | - Seung Ho Baek
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju, Chungcheongbuk, Republic of Korea
| | - Hyeong-Jun Park
- Department of Medical and Biological Sciences, The Catholic University of Korea, Bucheon 14662, Republic of Korea
| | - Yu-Sun Lee
- Department of Medical and Biological Sciences, The Catholic University of Korea, Bucheon 14662, Republic of Korea
| | - Yoo-Jin Bang
- Department of Medical and Biological Sciences, The Catholic University of Korea, Bucheon 14662, Republic of Korea
| | - Jae-Yong Kim
- Department of Medical and Biological Sciences, The Catholic University of Korea, Bucheon 14662, Republic of Korea
| | - Seo-Hyeon Bae
- Department of Medical and Biological Sciences, The Catholic University of Korea, Bucheon 14662, Republic of Korea
| | - Su Jeen Lee
- Department of Research and Development, SK Bioscience, Pangyoro 332, Bundang-gu, Republic of Korea
| | - Ki-Weon Seo
- Department of Research and Development, SK Bioscience, Pangyoro 332, Bundang-gu, Republic of Korea
| | - Hak Kim
- Department of Research and Development, SK Bioscience, Pangyoro 332, Bundang-gu, Republic of Korea
| | - Taewoo Kwon
- Department of Research and Development, SK Bioscience, Pangyoro 332, Bundang-gu, Republic of Korea
| | - Ji-Hwan Kim
- Department of Research and Development, SK Bioscience, Pangyoro 332, Bundang-gu, Republic of Korea
| | - Seonghwan Lee
- Department of Research and Development, SK Bioscience, Pangyoro 332, Bundang-gu, Republic of Korea
| | - Eunsom Kim
- Department of Research and Development, SK Bioscience, Pangyoro 332, Bundang-gu, Republic of Korea
| | - Yeonhwa Kim
- Division of Biotechnology, College of Environmental and Bioresources, Jeonbuk National University, Iksan 54596, Republic of Korea
| | - Jae-Hak Park
- Department of Laboratory Animal Medicine, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
| | - Sang-In Park
- Scripps Korea Antibody Institute, Chuncheon, Kangwon-do 24341, Republic of Korea
| | - Marta Gonçalves
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Byung Mook Weon
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Haengdueng Jeong
- Severance Biomedical Science Institute, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Ki Taek Nam
- Severance Biomedical Science Institute, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Kyung-Ah Hwang
- Department of Research and Development, SML Genetree, Baumero 225, Seocho-gu, Seoul 06740, Republic of Korea
| | - Jihye Kim
- Department of Medical Nutrition, Graduate School of East-West Medical Science, Kyung Hee University, Yongin 17104, Republic of Korea
| | - Hun Kim
- Department of Research and Development, SK Bioscience, Pangyoro 332, Bundang-gu, Republic of Korea
| | - Sang-Myeong Lee
- Present address: College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Republic of Korea.
| | - Jung Joo Hong
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju, Chungcheongbuk, Republic of Korea.
| | - Jae-Hwan Nam
- Department of Medical and Biological Sciences, The Catholic University of Korea, Bucheon 14662, Republic of Korea.
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16
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Abstract
Random packings are crucial in understanding arrangement and geometry of particles. Random packings of dry small particles may be subject to adhesion or friction, as expected theoretically and numerically. We explore experimentally random packings of dry colloids with X-ray nanotomography that directly provides three-dimensional structural and geometric information of dry colloidal packings. We find that dry colloidal packings, as characterized by contact number and packing density, are quite consistent with adhesive loose packings that significantly deviate from random loose packings for hard spheres. This study may offer direct evidence for adhesive loose packings comprising dry small particles, as proven by X-ray nanotomography.
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Affiliation(s)
- Yeseul Kim
- Soft Matter Physics Laboratory, SKKU Advanced Institute of Nanotechnology (SAINT), School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, Gyeonggi, 16419, South Korea
| | - Sangsul Lee
- Industrial Technology Convergence Center, Pohang Light Source, Pohang, Gyeongbuk, 37673, South Korea
| | - Jun Lim
- Industrial Technology Convergence Center, Pohang Light Source, Pohang, Gyeongbuk, 37673, South Korea
| | - Byung Mook Weon
- Soft Matter Physics Laboratory, SKKU Advanced Institute of Nanotechnology (SAINT), School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, Gyeonggi, 16419, South Korea. .,Research Center for Advanced Materials Technology, Sungkyunkwan University, Suwon, Gyeonggi, 16419, South Korea. .,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA.
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17
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Abstract
During the solvent evaporation of a thin film, Brownian rod-shaped particles self-assemble into microstructures and their orientation arrangements change while their volume fractions increase. We have studied the phenomena using a simple model which accounts for the anisotropic diffusion and the mean-field interaction of the particles. By numerically solving the Smoluchowski equation under moving boundary conditions, we obtain the spatiotemporal evolution of volume fractions and order parameters. It is shown that the evaporation dynamics alter the equilibrium orientational configuration of particles to meta-stable states. This alternation is possible by controlling either Péclet numbers or anisotropic diffusion rates. This understanding of the dynamic self-assembly of rod-shaped particles can be useful in manipulating the collective rod-arrangement in printing and coating technologies.
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Affiliation(s)
- Narina Jung
- Research Center for Advanced Materials Technology, Sungkyunkwan University, Suwon 16419, South Korea.
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18
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Abstract
We elucidate the evolution of the entrained air in drop impact on a wide range of liquids, using ultrafast X-ray phase-contrast imaging. We elaborate the retraction mechanism of the entrapped air film in terms of liquid viscosity. We found the criterion for deciding if the entrapped air evolves into single or double bubbles, as determined by competition among inertia, capillarity, and viscosity. Low viscosity and low surface tension induce a small daughter droplet encapsulated by a larger air shell bubble, forming an antibubble. We demonstrate a phase diagram for air evolution regarding hydrodynamics.
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Affiliation(s)
- Ji San Lee
- X-ray Imaging Center, Department of Materials Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, South Korea
| | - Byung Mook Weon
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419, South Korea. .,Research Center for Advanced Materials Technology, Sungkyunkwan University, Suwon, 16419, South Korea. .,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, 21218, USA.
| | - Su Ji Park
- X-ray Imaging Center, Department of Materials Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, South Korea
| | - Ji Tae Kim
- X-ray Imaging Center, Department of Materials Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, South Korea
| | - Jaeyeon Pyo
- X-ray Imaging Center, Department of Materials Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, South Korea
| | - Kamel Fezzaa
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois, 60439, USA
| | - Jung Ho Je
- X-ray Imaging Center, Department of Materials Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, South Korea.
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19
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Kim JY, Liu Z, Weon BM, Cohen T, Hui CY, Dufresne ER, Style RW. Extreme cavity expansion in soft solids: Damage without fracture. Sci Adv 2020; 6:eaaz0418. [PMID: 32258404 PMCID: PMC7101206 DOI: 10.1126/sciadv.aaz0418] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 01/03/2020] [Indexed: 05/07/2023]
Abstract
Cavitation is a common damage mechanism in soft solids. Here, we study this using a phase separation technique in stretched, elastic solids to controllably nucleate and grow small cavities by several orders of magnitude. The ability to make stable cavities of different sizes, as well as the huge range of accessible strains, allows us to systematically study the early stages of cavity expansion. Cavities grow in a scale-free manner, accompanied by irreversible bond breakage that is distributed around the growing cavity rather than being localized to a crack tip. Furthermore, cavities appear to grow at constant driving pressure. This has strong analogies with the plasticity that occurs surrounding a growing void in ductile metals. In particular, we find that, although elastomers are normally considered as brittle materials, small-scale cavity expansion is more like a ductile process. Our results have broad implications for understanding and controlling failure in soft solids.
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Affiliation(s)
- Jin Young Kim
- School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 16419, South Korea
| | - Zezhou Liu
- Department of Mechanical and Aerospace Engineering, Field of Theoretical and Applied Mechanics, Cornell University, Ithaca, NY 14853, USA
| | - Byung Mook Weon
- School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 16419, South Korea
| | - Tal Cohen
- Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Chung-Yuen Hui
- Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | | - Robert W. Style
- Department of Materials, ETH Zürich, Zürich 8093, Switzerland
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20
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Abstract
Hydrophobicity is abundant in nature and obtainable in industrial applications by roughening hydrophobic surfaces and engineering micropatterns. Classical wetting theory explains how surface roughness can enhance water repellency, assuming a droplet to have a flat bottom on top of micropatterned surfaces. However, in reality, a droplet can partially penetrate into micropatterns to form a round-bottom shape. Here, we systematically investigate the evolution of evaporating droplets on micropatterned surfaces with X-ray microscopy combined with three-dimensional finite element analyses and propose a theory that explains the wetting transition with gradually increasing penetration depth. We show that the penetrated state with a round bottom is inevitable for a droplet smaller than the micropattern-dependent critical size. Our finding reveals a more complete picture of hydrophobicity involving the partially penetrated state and its role in the wetting state transition and can be applied to understand the stability of water repellency of rough hydrophobic surfaces.
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Affiliation(s)
- Su Jin Lm
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology , Sungkyunkwan University , 2066 Seobu-ro, Jangan-gu , Suwon , Gyeonggi-do 16419 , Republic of Korea
- Research Center for Advanced Materials Technology , Sungkyunkwan University , 2066 Seobu-ro, Jangan-gu , Suwon , Gyeonggi-do 16419 , Republic of Korea
| | - Donggyu Kim
- Department of Mechanical Engineering , Korea Advanced Institute of Science and Technology , 291 Daehak-ro, Yuseong-gu , Daejeon 34141 , Republic of Korea
| | - Yeseul Kim
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology , Sungkyunkwan University , 2066 Seobu-ro, Jangan-gu , Suwon , Gyeonggi-do 16419 , Republic of Korea
- Research Center for Advanced Materials Technology , Sungkyunkwan University , 2066 Seobu-ro, Jangan-gu , Suwon , Gyeonggi-do 16419 , Republic of Korea
| | - Suyeon Jeong
- Department of Chemical Engineering, SKKU Advanced Institute of Nanotechnology , Sungkyunkwan University , 2066 Seobu-ro, Jangan-gu , Suwon , Gyeonggi-do 16419 , Republic of Korea
| | - Changhyun Pang
- Department of Chemical Engineering, SKKU Advanced Institute of Nanotechnology , Sungkyunkwan University , 2066 Seobu-ro, Jangan-gu , Suwon , Gyeonggi-do 16419 , Republic of Korea
| | - Seunghwa Ryu
- Department of Mechanical Engineering , Korea Advanced Institute of Science and Technology , 291 Daehak-ro, Yuseong-gu , Daejeon 34141 , Republic of Korea
| | - Byung Mook Weon
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology , Sungkyunkwan University , 2066 Seobu-ro, Jangan-gu , Suwon , Gyeonggi-do 16419 , Republic of Korea
- Research Center for Advanced Materials Technology , Sungkyunkwan University , 2066 Seobu-ro, Jangan-gu , Suwon , Gyeonggi-do 16419 , Republic of Korea
- Department of Biomedical Engineering , Johns Hopkins University , 3400 N. Charles Street , Baltimore , Maryland 21218 , United States
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21
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Abstract
Colloidal particles are essential materials for modern inkjet printing and coating. Here we demonstrate a versatile method to achieve hexagonal deposits of colloidal particles through droplet evaporation on hexagonal micropillar arrays. We identify how colloidal fluids turn into hexagonal deposits during evaporation with x-ray tomography. Interestingly, evaporation-driven hexagonal deposits are quite crack-free uniform. We attribute hexagonal deposit shape control to local contact line pinning by colloidal particles and geometric constraints by micropillar arrays. This deposition strategy offers a feasibility for high-quality evaporation-driven crack-free uniform polygonal deposits of colloidal particles for diverse applications.
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Affiliation(s)
- Hee Kyeong Park
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 16419, South Korea.,Research Center for Advanced Materials Technology, Sungkyunkwan University, Suwon 16419, South Korea
| | - Yeseul Kim
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 16419, South Korea.,Research Center for Advanced Materials Technology, Sungkyunkwan University, Suwon 16419, South Korea
| | - Hyeongho Min
- Department of Chemical Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 16419, South Korea
| | - Changhyun Pang
- Department of Chemical Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 16419, South Korea
| | - Byung Mook Weon
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 16419, South Korea.,Research Center for Advanced Materials Technology, Sungkyunkwan University, Suwon 16419, South Korea
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22
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Yeo SJ, Oh MJ, Jun HM, Lee M, Bae JG, Kim Y, Park KJ, Lee S, Lee D, Weon BM, Lee WB, Kwon SJ, Yoo PJ. A Plesiohedral Cellular Network of Graphene Bubbles for Ultralight, Strong, and Superelastic Materials. Adv Mater 2018; 30:e1802997. [PMID: 30156738 DOI: 10.1002/adma.201802997] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 07/16/2018] [Indexed: 05/16/2023]
Abstract
Advanced materials with low density and high strength impose transformative impacts in the construction, aerospace, and automobile industries. These materials can be realized by assembling well-designed modular building units (BUs) into interconnected structures. This study uses a hierarchical design strategy to demonstrate a new class of carbon-based, ultralight, strong, and even superelastic closed-cellular network structures. Here, the BUs are prepared by a multiscale design approach starting from the controlled synthesis of functionalized graphene oxide nanosheets at the molecular- and nanoscale, leading to the microfluidic fabrication of spherical solid-shelled bubbles at the microscale. Then, bubbles are strategically assembled into centimeter-scale 3D structures. Subsequently, these structures are transformed into self-interconnected and structurally reinforced closed-cellular network structures with plesiohedral cellular units through post-treatment, resulting in the generation of 3D graphene lattices with rhombic dodecahedral honeycomb structure at the centimeter-scale. The 3D graphene suprastructure concurrently exhibits the Young's modulus above 300 kPa while retaining a light density of 7.7 mg cm-3 and sustaining the elasticity against up to 87% of the compressive strain benefiting from efficient stress dissipation through the complete space-filling closed-cellular network. The method of fabricating the 3D graphene closed-cellular structure opens a new pathway for designing lightweight, strong, and superelastic materials.
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Affiliation(s)
- Seon Ju Yeo
- Nanophotonics Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Min Jun Oh
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Hyun Min Jun
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Minhwan Lee
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul, 08826, Republic of Korea
| | - Jung Gun Bae
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul, 08826, Republic of Korea
| | - Yeseul Kim
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Kyung Jin Park
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Seungwoo Lee
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Daeyeon Lee
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Byung Mook Weon
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
- School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Won Bo Lee
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul, 08826, Republic of Korea
| | - Seok Joon Kwon
- Nanophotonics Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Pil J Yoo
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
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23
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Abstract
Drying-mediated patterning of colloidal particles is a physical phenomenon that must be understood in inkjet printing technology to obtain crack-free uniform colloidal films. Here we experimentally study the drying-mediated patterns of a model colloid-polymer suspension and specifically observe how the deposit pattern appears after droplet evaporation by varying particle size and polymer concentration. We find that at a high polymer concentration, the ring-like pattern appears in suspensions with large colloids, contrary to suppression of ring formation in suspensions with small colloids thanks to colloid-polymer interactions. We attribute this unexpected reversal behavior to hydrodynamics and size dependence of colloid-polymer interactions. This finding would be very useful in developing control of drying-mediated self-assembly to produce crack-free uniform patterns from colloidal fluids.
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Affiliation(s)
- Seul-A Ryu
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419, Korea
| | - Jin Young Kim
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419, Korea
| | - So Youn Kim
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Korea
| | - Byung Mook Weon
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419, Korea.
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24
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Cho K, Hwang IG, Kim Y, Lim SJ, Lim J, Kim JH, Gim B, Weon BM. Low internal pressure in femtoliter water capillary bridges reduces evaporation rates. Sci Rep 2016; 6:22232. [PMID: 26928329 PMCID: PMC4772007 DOI: 10.1038/srep22232] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 02/08/2016] [Indexed: 11/23/2022] Open
Abstract
Capillary bridges are usually formed by a small liquid volume in a confined space between two solid surfaces. They can have a lower internal pressure than the surrounding pressure for volumes of the order of femtoliters. Femtoliter capillary bridges with relatively rapid evaporation rates are difficult to explore experimentally. To understand in detail the evaporation of femtoliter capillary bridges, we present a feasible experimental method to directly visualize how water bridges evaporate between a microsphere and a flat substrate in still air using transmission X-ray microscopy. Precise measurements of evaporation rates for water bridges show that lower water pressure than surrounding pressure can significantly decrease evaporation through the suppression of vapor diffusion. This finding provides insight into the evaporation of ultrasmall capillary bridges.
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Affiliation(s)
- Kun Cho
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746, Korea
| | - In Gyu Hwang
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746, Korea
| | - Yeseul Kim
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746, Korea
| | - Su Jin Lim
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746, Korea
| | - Jun Lim
- Beamline Division, Pohang Light Source, Hyoja, Pohang, Kyung-buk, 790-784, Korea
| | - Joon Heon Kim
- Advanced Photonics Research Institute, Gwangju Institute of Science and Technology (GIST), Gwangju, 500-712, Korea
| | - Bopil Gim
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 305-701, Korea
| | - Byung Mook Weon
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746, Korea
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25
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Lee JS, Park SJ, Lee JH, Weon BM, Fezzaa K, Je JH. Origin and dynamics of vortex rings in drop splashing. Nat Commun 2015; 6:8187. [PMID: 26337704 PMCID: PMC4569801 DOI: 10.1038/ncomms9187] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 07/28/2015] [Indexed: 11/09/2022] Open
Abstract
A vortex is a flow phenomenon that is very commonly observed in nature. More than a century, a vortex ring that forms during drop splashing has caught the attention of many scientists due to its importance in understanding fluid mixing and mass transport processes. However, the origin of the vortices and their dynamics remain unclear, mostly due to the lack of appropriate visualization methods. Here, with ultrafast X-ray phase-contrast imaging, we show that the formation of vortex rings originates from the energy transfer by capillary waves generated at the moment of the drop impact. Interestingly, we find a row of vortex rings along the drop wall, as demonstrated by a phase diagram established here, with different power-law dependencies of the angular velocities on the Reynolds number. These results provide important insight that allows understanding and modelling any type of vortex rings in nature, beyond just vortex rings during drop splashing. Drop impact on a liquid surface leads to the formation of vortex rings, but this process is still poorly understood due to the lack of effective experimental characterization. Here, Lee et al. visualize the process using ultrafast X-ray phase-contrast imaging and follow the dynamics of vortex rings.
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Affiliation(s)
- Ji San Lee
- Department of Materials Science and Engineering, X-ray Imaging Center, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang 790-784, Korea
| | - Su Ji Park
- Department of Materials Science and Engineering, X-ray Imaging Center, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang 790-784, Korea
| | - Jun Ho Lee
- Department of Materials Science and Engineering, X-ray Imaging Center, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang 790-784, Korea
| | - Byung Mook Weon
- School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746, Korea
| | - Kamel Fezzaa
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA
| | - Jung Ho Je
- Department of Materials Science and Engineering, X-ray Imaging Center, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang 790-784, Korea
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26
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Abstract
Crack formation is a frequent result of residual stress release from colloidal films made by the evaporation of colloidal droplets containing nanoparticles. Crack prevention is a significant task in industrial applications such as painting and inkjet printing with colloidal nanoparticles. Here, we illustrate how colloidal drops evaporate and how crack generation is dependent on the particle size and initial volume fraction, through direct visualization of the individual colloids with confocal laser microscopy. To prevent crack formation, we suggest use of a versatile method to control the colloid-polymer interactions by mixing a nonadsorbing polymer with the colloidal suspension, which is known to drive gelation of the particles with short-range attraction. Gelation-driven crack prevention is a feasible and simple method to obtain crack-free, uniform coatings through drying-mediated assembly of colloidal nanoparticles.
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Affiliation(s)
- Jin Young Kim
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746, Korea
| | - Kun Cho
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746, Korea
| | - Seul-A Ryu
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746, Korea
| | - So Youn Kim
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Korea
| | - Byung Mook Weon
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746, Korea
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27
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Abstract
As humans live longer, the precise modeling of mortality curves in very old age is becoming more important in aging research and public health. Here, we address a methodology that utilizes a modified stretched exponential survival function where a stretched exponent is relevant to heterogeneity in human populations. This function allows better estimation of the maximum human lifespan by providing a good description of the mortality curves in very old age. Demographic analysis of Swedish females over three recent decades revealed an important trend: the maximum human lifespan (existing around 125 years) gradually decreased at a constant rate of ~1.6 years per decade, while the characteristic life gradually increased at a constant rate of ~1.2 years per decade. This trend indicates that the number of aging people is increasingly concentrated at very old age, which is consistent with the definition of population aging. Importantly analyzing the stretched exponents would help in evaluating the heterogeneity trends in human populations.
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Affiliation(s)
- Byung Mook Weon
- School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 440-746, Korea,
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28
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Abstract
A bubble merged from two parent bubbles with different size tends to be placed closer to the larger parent. This phenomenon is known as the coalescence preference. Here we demonstrate that the coalescence preference can be blocked inside a densely packed cluster of bubbles. We utilized high-speed high-resolution X-ray microscopy to clearly visualize individual coalescence events inside densely packed microbubbles with a local packing fraction of ~40%. The surface energy release theory predicts an exponent of 5 in a relation between the relative coalescence position and the parent size ratio, whereas our observation for coalescence in densely packed microbubbles shows a different exponent of 2. We believe that this result would be important to understand the reality of coalescence dynamics in a variety of packing situations of soft matter.
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Affiliation(s)
- Yeseul Kim
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746, Korea
| | - Su Jin Lim
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746, Korea
| | - Bopil Gim
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Korea
| | - Byung Mook Weon
- Soft Matter Physics Laboratory, School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746, Korea
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29
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Park SJ, Weon BM, Lee JS, Lee J, Kim J, Je JH. Visualization of asymmetric wetting ridges on soft solids with X-ray microscopy. Nat Commun 2014; 5:4369. [PMID: 25007777 PMCID: PMC4104447 DOI: 10.1038/ncomms5369] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 06/10/2014] [Indexed: 12/22/2022] Open
Abstract
One of the most questionable issues in wetting is the force balance that includes the vertical component of liquid surface tension. On soft solids, the vertical component leads to a microscopic protrusion of the contact line, that is, a 'wetting ridge'. The wetting principle determining the tip geometry of the ridge is at the heart of the issues over the past half century. Here we reveal a universal wetting principle from the ridge tips directly visualized with high spatio-temporal resolution of X-ray microscopy. We find that the cusp of the ridge is bent with an asymmetric tip, whose geometry is invariant during ridge growth or by surface softness. This singular asymmetry is deduced by linking the macroscopic and microscopic contact angles to Young and Neuman laws, respectively. Our finding shows that this dual-scale approach would be contributable to a general framework in elastowetting, and give hints to issues in cell-substrate interaction and elasto-capillary problems.
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Affiliation(s)
- Su Ji Park
- X-ray Imaging Center, Department of Materials Science and Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 790-784, South Korea
| | - Byung Mook Weon
- School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746, South Korea
| | - Ji San Lee
- X-ray Imaging Center, Department of Materials Science and Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 790-784, South Korea
| | - Junho Lee
- X-ray Imaging Center, Department of Materials Science and Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 790-784, South Korea
| | - Jinkyung Kim
- X-ray Imaging Center, Department of Materials Science and Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 790-784, South Korea
| | - Jung Ho Je
- X-ray Imaging Center, Department of Materials Science and Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 790-784, South Korea
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30
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Jung JW, Jeon HM, Pyo J, Lim JH, Weon BM, Kohmura Y, Ishikawa T, Je JH. Four-dimensional visualization of rising microbubbles. Sci Rep 2014; 4:5083. [PMID: 24866552 PMCID: PMC4035580 DOI: 10.1038/srep05083] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 05/07/2014] [Indexed: 11/09/2022] Open
Abstract
Four-dimensional imaging, which indicates imaging in three spatial dimensions as a function of time, provides useful evidence to investigate the interactions of rising bubbles. However, this has been largely unexplored for microbubbles, mostly due to problems associated with strong light scattering and shallow depth of field in optical imaging. Here, tracking x-ray microtomography is used to visualize rising microbubbles in four dimensions. Bubbles are tracked by moving the cell to account for their rise velocity. The sizes, shapes, time-dependent positions, and velocities of individual rising microbubbles are clearly identified, despite substantial overlaps between bubbles in the field of view. Our tracking x-ray microtomography affords opportunities for understanding bubble-bubble (or particle) interactions at microscales - important in various fields such as microfluidics, biomechanics, and floatation.
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Affiliation(s)
- Ji Won Jung
- X-ray Imaging Center, Department of Materials Science and Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 790-784, Korea
| | - Hyung Min Jeon
- X-ray Imaging Center, Department of Materials Science and Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 790-784, Korea
| | - Jaeyeon Pyo
- X-ray Imaging Center, Department of Materials Science and Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 790-784, Korea
| | - Jae-Hong Lim
- Pohang Accelerator Laboratory, San 31, Hyoja-dong, Pohang 790-784, Korea
| | - Byung Mook Weon
- School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746, Korea
| | - Yoshiki Kohmura
- RIKEN/SPring-8, 1-1-1 Kouto, Mikazuki-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Tetsuya Ishikawa
- RIKEN/SPring-8, 1-1-1 Kouto, Mikazuki-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Jung Ho Je
- 1] X-ray Imaging Center, Department of Materials Science and Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 790-784, Korea [2] RIKEN/SPring-8, 1-1-1 Kouto, Mikazuki-cho, Sayo-gun, Hyogo 679-5148, Japan
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31
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Chang S, Kwon N, Weon BM, Kim J, Rhee CK, Choi HS, Kohmura Y, Yamamoto M, Ishikawa T, Je JH. Tracking X-ray microscopy for alveolar dynamics in live intact mice. Sci Rep 2013; 3:1304. [PMID: 23416838 PMCID: PMC3575013 DOI: 10.1038/srep01304] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 02/01/2013] [Indexed: 01/09/2023] Open
Abstract
Here we report a tracking X-ray microscopy (TrXM) as a novel methodology by using upper right lung apices alveoli in live intact mice. By enabling tracking of individual alveolar movements during respiration, TrXM identifies alveolar dynamics: individual alveoli in the upper lung apices show a small size increment as 4.9 ± 0.4% (mean ± s.e.m.) during respiration while their shapes look almost invariant. TrXM analysis in alveolar dynamics would be significant for better understanding of alveolar-based diseases, for instance, ventilator induced lung injury (VILI) in acute respiratory distress syndrome (ARDS).
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Affiliation(s)
- Soeun Chang
- X-ray Imaging Center, Pohang University of Science and Technology, Hyoja-dong, Pohang, Korea
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32
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Abstract
Colloidal particles suspended in a fluid usually inhibit complete wetting of the fluid on a solid surface and cause pinning of the contact line, known as self-pinning. We show differences in spreading and drying behaviors of pure and colloidal droplets using optical and confocal imaging methods. These differences come from spreading inhibition by colloids confined at a contact line. We propose a self-pinning mechanism based on spreading inhibition by colloids. We find a good agreement between the mechanism and the experimental result taken by directly tracking individual colloids near the contact lines of evaporating colloidal droplets.
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Affiliation(s)
- Byung Mook Weon
- X-ray Imaging Center, Department of Materials Science and Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 790-784, Korea.
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33
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Abstract
Colloidal droplets including micro- and nanoparticles generally leave a ringlike stain, called the "coffee ring," after evaporation. We show that fingering emerges during evaporation inside the coffee ring, resulting from a bidispersed colloidal mixture of micro- and nanoparticles. Microscopic observations suggest that finger formation is driven by competition between the coffee-ring and Marangoni effects, especially when the inward Marangoni flow is overwhelmed by the outward coffee-ring flow. This finding could help to understand the variety of the final deposition patterns of colloidal droplets.
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Affiliation(s)
- Byung Mook Weon
- X-ray Imaging Center, Department of Materials Science and Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 790-784, Korea.
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34
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Lee JS, Weon BM, Je JH, Fezzaa K. How does an air film evolve into a bubble during drop impact? Phys Rev Lett 2012; 109:204501. [PMID: 23215492 DOI: 10.1103/physrevlett.109.204501] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 09/14/2012] [Indexed: 06/01/2023]
Abstract
When a liquid drop impacts a solid surface, air is generally entrapped underneath. Using ultrafast x-ray phase-contrast imaging, we directly visualized the profile of an entrapped air film and its evolution into a bubble during drop impact. We identified a complicated evolution process that consists of three stages: inertial retraction of the air film, contraction of the top air surface into a bubble, and pinch-off of a daughter droplet inside the bubble. Energy transfer during retraction drives the contraction and pinch-off of a daughter droplet. The wettability of the solid surface affects the detachment of the bubble, suggesting a method for bubble elimination in many drop-impact applications.
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Affiliation(s)
- Ji San Lee
- X-ray Imaging Center, Department of Materials Science and Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 790-784, Korea
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35
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Abstract
The ageing of the population is an issue in wealthy countries worldwide because of increasing costs for health care and welfare. Survival curves taken from demographic life tables may help shed light on the hypotheses that humans are living longer and that human populations are growing older. We describe a methodology that enables us to obtain separate measurements of scale and shape variances in survival curves. Specifically, ‘living longer’ is associated with the scale variance of survival curves, whereas ‘growing older’ is associated with the shape variance. We show how the scale and shape of survival curves have changed over time during recent decades, based on period and cohort female life tables for selected wealthy countries. Our methodology will be useful for performing better tracking of ageing statistics and it is possible that this methodology can help identify the causes of current trends in human ageing.
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Affiliation(s)
- Byung Mook Weon
- X-ray Imaging Center, Department of Materials Science and Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 790-784, Korea.
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36
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Abstract
During bubble or droplet coalescence, there is a puzzling tendency for the coalesced bubble or droplet to be preferentially placed closer to the larger of its two parents. We confirm that this preference is a function of parent size ratio by directly visualizing coalescing air bubbles on an oil-water interface and coalescing water droplets immersed in oil. We find that the final position of the coalesced sphere is controlled by surface energy release and is related to the parent size ratio by a power-law relationship.
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Affiliation(s)
- Byung Mook Weon
- X-ray Imaging Center, Department of Materials Science and Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 790-784, Korea.
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37
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Abstract
Living systems inevitably undergo a progressive deterioration of physiological function with age and an increase of vulnerability to disease and death. To maintain health and survival, living systems should optimize survival strategies with adaptive interactions among molecules, cells, organs, individuals, and environments, which arises plasticity in survival curves of living systems. In general, survival dynamics in a population is mathematically depicted by a survival rate, which monotonically changes from 1 to 0 with age. It would be then useful to find an adequate function to describe complicated survival dynamics. Here we describe a flexible survival function, derived from the stretched exponential function by adopting an age-dependent shaping exponent. We note that the exponent is associated with the fractal-like scaling in cumulative mortality rate. The survival function well depicts general features in survival curves; healthy populations exhibit plasticity and evolve towards rectangular-like survival curves, as examples in humans or laboratory animals.
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Affiliation(s)
- Byung Mook Weon
- X-ray Imaging Center, Department of Materials Science and Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang, 790-784, Korea
| | - Jung Ho Je
- X-ray Imaging Center, Department of Materials Science and Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang, 790-784, Korea
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38
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Abstract
We present quantitative evidence for x-ray-induced water vaporization: water is vaporized at a rate of 5.5 pL/s with the 1-Å-wavelength x-ray irradiation of ~0.1 photons per Å(2); moreover, water vapor is reversibly condensed during pauses in irradiation. This result fundamentally suggests that photoionization induces vaporization. This phenomenon is attributed to surface-tension reduction by ionization and would be universally important in radiological and electrohydrodynamic situations.
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Affiliation(s)
- B M Weon
- X-ray Imaging Center, Department of Materials Science and Engineering, Pohang University of Science and Technology, San 31, Pohang 790-784, South Korea.
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39
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Weon BM, Kim JT, Je JH, Yi JM, Wang S, Lee WK. Colloid coalescence with focused x rays. Phys Rev Lett 2011; 107:018301. [PMID: 21797577 DOI: 10.1103/physrevlett.107.018301] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Revised: 02/17/2011] [Indexed: 05/31/2023]
Abstract
We show direct evidence that focused x rays enable us to merge polymer colloidal particles at room temperature. This phenomenon is ascribed to the photochemical scission of colloids with x rays, reducing the molecular weight, glass transition temperature, surface tension, and viscosity of colloids. The observation of the neck bridge growth with time shows that the x-ray-induced colloid coalescence is analogous to viscoelastic coalescence. This finding suggests a feasible protocol of photonic nanofabrication by sintering or welding of polymers, without thermal damage, using x-ray photonics.
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Affiliation(s)
- B M Weon
- X-ray Imaging Center, Department of Materials Science and Engineering, Pohang University of Science and Technology, Korea.
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40
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Lee JS, Weon BM, Park SJ, Je JH, Fezzaa K, Lee WK. Size limits the formation of liquid jets during bubble bursting. Nat Commun 2011; 2:367. [PMID: 21694715 PMCID: PMC3156824 DOI: 10.1038/ncomms1369] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 05/25/2011] [Indexed: 11/30/2022] Open
Abstract
A bubble reaching an air–liquid interface usually bursts and forms a liquid jet. Jetting is relevant to climate and health as it is a source of aerosol droplets from breaking waves. Jetting has been observed for large bubbles with radii of R≫100 μm. However, few studies have been devoted to small bubbles (R<100 μm) despite the entrainment of a large number of such bubbles in sea water. Here we show that jet formation is inhibited by bubble size; a jet is not formed during bursting for bubbles smaller than a critical size. Using ultrafast X-ray and optical imaging methods, we build a phase diagram for jetting and the absence of jetting. Our results demonstrate that jetting in bubble bursting is analogous to pinching-off in liquid coalescence. The coalescence mechanism for bubble bursting may be useful in preventing jet formation in industry and improving climate models concerning aerosol production. A bubble at an air–liquid interface can form a liquid jet upon bursting, spraying aerosol droplets into the air. Lee et al. show that jetting is analogous to pinching-off in liquid coalescence, which may be useful in applications that prevent jet formation and in the improved incorporation of aerosols in climate models.
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Affiliation(s)
- Ji San Lee
- X-ray Imaging Center, Department of Materials Science and Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 790-784, Korea
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41
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Weon BM, Je JH, Gremaud G. Hard X-ray imaging for landslide research. J Synchrotron Radiat 2010; 17:817-820. [PMID: 20975231 DOI: 10.1107/s0909049510035363] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Accepted: 09/02/2010] [Indexed: 05/30/2023]
Abstract
Synchrotron phase-contrast hard X-ray imaging is used to provide highly efficient direct visualization of landslide dynamics and granular flows in fully wet granular piles. High penetration capability and phase-contrast enhancement of hard X-rays offer marked advantages in the precise tracking of individual granular movements through a thick water medium. It is revealed that the stress accumulation follows a power-law evolution while the relaxation follows an exponential one. The onset of landslide emerges at the trade-off of the two evolutions.
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Affiliation(s)
- B M Weon
- Department of Physics, School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA.
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Weon BM, Je JH. Capillary force repels coffee-ring effect. Phys Rev E Stat Nonlin Soft Matter Phys 2010; 82:015305. [PMID: 20866682 DOI: 10.1103/physreve.82.015305] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Revised: 05/19/2010] [Indexed: 05/13/2023]
Abstract
When a coffee drop dries on a solid surface, it leaves a ringlike deposit along the edge and this is known as the "coffee-ring effect." We find a different motion of particles repelling the coffee-ring effect in drying droplets; the motion of particles that is initially toward the edge by the coffee-ring effect is reversed toward the center by a capillary force. The reversal takes place when the capillary force prevails over the outward coffee-ring flow. We discuss the geometric constraints for the capillary force and the reverse motion. Our findings of reversal phenomena would be important in many scenarios of drying colloidal fluids.
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Affiliation(s)
- Byung Mook Weon
- Department of Physics, School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA.
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Abstract
We observed that hard X-ray irradiation modifies the wettability of a variety of inorganic materials. The smooth surfaces of all tested inorganic materials (ZnO, p-Si, Al2O3, SrTiO3, TiN, ZnS, CuO, Ag2O, and Cr2O3) change during irradiation to a state of superhydrophilic wettability, and such changes are explained by the accumulation of positive surface charges by photoelectron emission. The initial wettability state is re-established within several minutes of storage in deionized water.
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Affiliation(s)
- Yong Bum Kwon
- X-ray Imaging Center, Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang, South Korea
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Abstract
We discovered that intense irradiation by hard-x-ray strongly decreases the effects of natural surface tension of water in droplets and capillary tubes. The effect was revealed by direct experimental observations with phase contrast microradiology. A model based on ionization and surface charging explains this so far undetected phenomenon. The effect can impact the results of many experimental techniques based on x rays. This is an example of the largely unexplored effects that can be produced by extreme intense x-ray irradiation-an important issue due to current development of x-ray free-electron-lasers with unprecedented brilliance.
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Affiliation(s)
- B M Weon
- Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang, 790-784, Korea
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Yoon CY, Sung DJ, Lee JH, Kim AR, Oh CW, Je JH, Weon BM, Seol SK, Pyun A, Hwu Y, Margaritondo G, Joo KJ, Yoon DK. Imaging of renal and prostate carcinoma with refractive index radiology. Int J Urol 2007; 14:96-103. [PMID: 17302563 DOI: 10.1111/j.1442-2042.2007.01614.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIM Having better edge enhancement and penetrating power, refractive index radiology is suitable for the imaging of weakly absorbing objects such as tissue specimens. In this study the potential of refractive index radiology was evaluated for the imaging of renal cell carcinoma (RCC) and prostate cancer (PCA). METHODS Specimens were cut in 3 mm and 4 microm thickness for X-ray radiology and hematoxylin and eosin (HE) staining, respectively. Radiographic images of RCC and PCA were obtained using the synchrotron hard X-rays from the 7B2 beam-line of the Pohang Light Source (PLS). The imaging technique applied was phase-contrast radiology based on the refraction enhancement mechanism. The resulting radiographic images were analyzed in correlation with those of optical microscopy. RESULTS Using unmonochromatized hard X-rays, it was possible to obtain images with clear edge enhancement and relatively large field of view (6 cm x 6 cm). Even with overlapping signals from thick samples (more than 700-fold thicker than microscopic images), radiographic images clearly showed histological information of organelles in normal kidney such as glomeruli, tubules, and collecting ducts. Histological information of RCC including tumor subtypes and minute changes such as cystic degeneration could be identified without difficulty. The radiographic images of the prostate were comparable with those of low magnification optical microscopy, providing good visualization of normal microstructures such as adenoma, smooth muscle, and normal glands, or differentiation of tiny tumors from surrounding normal tissues. CONCLUSIONS These results suggest the potential of refractive index radiology to provide a new way of imaging biological tissues with low absorption contrast such as RCC and PCA.
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Affiliation(s)
- Cheol Yong Yoon
- Department of Urology, College of Medicine, Korea University, Seoul, Korea
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Pyun A, Bell JR, Won KH, Weon BM, Seol SK, Je JH, Macosko CW. Synchrotron X-ray Microtomography for 3D Imaging of Polymer Blends. Macromolecules 2007. [DOI: 10.1021/ma062635+] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Koh SB, Suh SI, Lee DH, Kim AR, Oh CH, Yoon JS, Weon BM, Seol SK, Pyun AR, Je JH, Hwu Y, Margaritondo G. Phase contrast radiography of Lewy bodies in Parkinson disease. Neuroimage 2006; 32:566-9. [PMID: 16766209 DOI: 10.1016/j.neuroimage.2006.04.217] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2005] [Revised: 02/23/2006] [Accepted: 04/05/2006] [Indexed: 11/24/2022] Open
Abstract
Parkinson's disease (PD), defined as a neurodegenerative disorder, is characterized by the loss of dopaminergic neurons and the presence of Lewy bodies in neurons. Morphological study of Lewy bodies is important to identify the causes and the processes of PD. Here, we investigate a possibility of phase contrast radiography using coherent synchrotron X-rays to explore the microscopic details of Lewy bodies in thick (approximately 3 mm) midbrain tissues. Autopsied midbrain tissues of a PD patient were sliced in 3 mm thickness and then examined using synchrotron X-rays from the 7B2 beamline of the Pohang Light Source. Refraction-enhanced phase contrast radiography and microtomography were adopted to identify dark core and dim edge of Lewy bodies in neurons. The morphology of Lewy bodies was clearly revealed by the phase contrast radiography in very thick (3 mm) midbrain tissues without any staining treatment. Three-dimensional volume rendered microtomography of the autopsied midbrain tissues demonstrates striking evidence that several Lewy bodies are agglomerated by dim edges in a neuron. We suggest that the phase contrast radiography could be a useful tool to morphologically investigate the causes or the processes in PD.
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Affiliation(s)
- S B Koh
- Department of Neurology, Korea University College of Medicine, Korea.
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