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Yu H, Kang D, Whang M, Kim T, Kim J. A Microfluidic Model Artery for Studying the Mechanobiology of Endothelial Cells. Adv Healthc Mater 2021; 10:e2100508. [PMID: 34297476 DOI: 10.1002/adhm.202100508] [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] [Received: 03/16/2021] [Revised: 06/25/2021] [Indexed: 11/07/2022]
Abstract
Recent vascular mechanobiology studies find that endothelial cells (ECs) convert multiple mechanical forces into functional responses in a nonadditive way, suggesting that signaling pathways such as those regulating cytoskeleton may be shared among the processes of converting individual forces. However, previous in vitro EC-culture platforms are inherent with extraneous mechanical components, which may saturate or insufficiently activate the shared signaling pathways and accordingly, may misguide EC mechanobiological responses being investigated. Here, a more physiologically relevant model artery is reported that accurately reproduces most of the mechanical forces found in vivo, which can be individually varied in any combination to pathological levels to achieve diseased states. Arterial geometries of normal and diseased states are also realized. By mimicking mechanical microenvironments of early-stage atherosclerosis, it is demonstrated that the elevated levels of the different types of stress experienced by ECs strongly correlate with the disruption of barrier integrity, suggesting that boundaries of an initial lesion could be sites for efficient disease progression.
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Affiliation(s)
- Hyeonji Yu
- Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, 04107, Republic of Korea
| | - Dongwon Kang
- Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, 04107, Republic of Korea
| | - Minji Whang
- Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, 04107, Republic of Korea
| | - Taeyoung Kim
- Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, 04107, Republic of Korea
| | - Jungwook Kim
- Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, 04107, Republic of Korea
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Oh J, Baek D, Lee TK, Kang D, Hwang H, Go EM, Jeon I, You Y, Son C, Kim D, Whang M, Nam K, Jang M, Park JH, Kwak SK, Kim J, Lee J. Dynamic multimodal holograms of conjugated organogels via dithering mask lithography. Nat Mater 2021; 20:385-394. [PMID: 33398120 DOI: 10.1038/s41563-020-00866-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 10/23/2020] [Indexed: 06/12/2023]
Abstract
Polymeric materials have been used to realize optical systems that, through periodic variations of their structural or optical properties, interact with light-generating holographic signals. Complex holographic systems can also be dynamically controlled through exposure to external stimuli, yet they usually contain only a single type of holographic mode. Here, we report a conjugated organogel that reversibly displays three modes of holograms in a single architecture. Using dithering mask lithography, we realized two-dimensional patterns with varying cross-linking densities on a conjugated polydiacetylene. In protic solvents, the organogel contracts anisotropically to develop optical and structural heterogeneities along the third dimension, displaying holograms in the form of three-dimensional full parallax signals, both in fluorescence and bright-field microscopy imaging. In aprotic solvents, these heterogeneities diminish as organogels expand, recovering the two-dimensional periodicity to display a third hologram mode based on iridescent structural colours. Our study presents a next-generation hologram manufacturing method for multilevel encryption technologies.
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Affiliation(s)
- Jongwon Oh
- School of Energy and Chemical Engineering, Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan Metropolitan City, Republic of Korea
| | - Dahye Baek
- School of Energy and Chemical Engineering, Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan Metropolitan City, Republic of Korea
| | - Tae Kyung Lee
- School of Energy and Chemical Engineering, Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan Metropolitan City, Republic of Korea
- Photovoltaics Research Department, Korea Institute of Energy Research (KIER), Daejeon, Republic of Korea
| | - Dongwon Kang
- Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, Republic of Korea
| | - Hyeri Hwang
- School of Energy and Chemical Engineering, Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan Metropolitan City, Republic of Korea
| | - Eun Min Go
- School of Energy and Chemical Engineering, Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan Metropolitan City, Republic of Korea
| | - Inkyu Jeon
- School of Energy and Chemical Engineering, Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan Metropolitan City, Republic of Korea
| | - Younghoon You
- School of Energy and Chemical Engineering, Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan Metropolitan City, Republic of Korea
| | - Changil Son
- School of Energy and Chemical Engineering, Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan Metropolitan City, Republic of Korea
| | - Dowon Kim
- School of Energy and Chemical Engineering, Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan Metropolitan City, Republic of Korea
| | - Minji Whang
- Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, Republic of Korea
| | - Kibum Nam
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan Metropolitan City, Republic of Korea
| | - Moonjeong Jang
- Thin Film Materials Research Center, Korea Research Institute of Chemical Technology (KRICT), Daejeon, Republic of Korea
| | - Jung-Hoon Park
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan Metropolitan City, Republic of Korea
| | - Sang Kyu Kwak
- School of Energy and Chemical Engineering, Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan Metropolitan City, Republic of Korea.
| | - Jungwook Kim
- Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, Republic of Korea.
| | - Jiseok Lee
- School of Energy and Chemical Engineering, Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan Metropolitan City, Republic of Korea.
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Whang M, Kim J. Synthetic hydrogels with stiffness gradients for durotaxis study and tissue engineering scaffolds. Tissue Eng Regen Med 2016; 13:126-139. [PMID: 30603392 PMCID: PMC6170857 DOI: 10.1007/s13770-016-0026-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 03/02/2016] [Accepted: 03/03/2016] [Indexed: 12/21/2022] Open
Abstract
Migration of cells along the right direction is of paramount importance in a number of in vivo circumstances such as immune response, embryonic developments, morphogenesis, and healing of wounds and scars. While it has been known for a while that spatial gradients in chemical cues guide the direction of cell migration, the significance of the gradient in mechanical cues, such as stiffness of extracellular matrices (ECMs), in directed migration of cells has only recently emerged. With advances in synthetic chemistry, micro-fabrication techniques, and methods to characterize mechanical properties at a length scale even smaller than a single cell, synthetic ECMs with spatially controlled stiffness have been created with variations in design parameters. Since then, the synthetic ECMs have served as platforms to study the migratory behaviors of cells in the presence of the stiffness gradient of ECM and also as scaffolds for the regeneration of tissues. In this review, we highlight recent studies in cell migration directed by the stiffness gradient, called durotaxis, and discuss the mechanisms of durotaxis. We also summarize general methods and design principles to create synthetic ECMs with the stiffness gradients and, finally, conclude by discussing current limitations and future directions of synthetic ECMs for the study of durotaxis and the scaffold for tissue engineering.
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Affiliation(s)
- Minji Whang
- Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, Korea
| | - Jungwook Kim
- Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, Korea
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Park S, Won MJ, Mun S, Lee EC, Whang M. Does visual fatigue from 3D displays affect autonomic regulation and heart rhythm? Int J Psychophysiol 2014; 92:S0167-8760(14)00056-7. [PMID: 24534823 DOI: 10.1016/j.ijpsycho.2014.02.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 02/03/2014] [Accepted: 02/09/2014] [Indexed: 11/16/2022]
Abstract
Most investigations into the negative effects of viewing stereoscopic 3D content on human health have addressed 3D visual fatigue and visually induced motion sickness (VIMS). Very few, however, have looked into changes in autonomic balance and heart rhythm, which are homeostatic factors that ought to be taken into consideration when assessing the overall impact of 3D video viewing on human health. In this study, 30 participants were randomly assigned to two groups: one group watching a 2D video, (2D-group) and the other watching a 3D video (3D-group). The subjects in the 3D-group showed significantly increased heart rates (HR), indicating arousal, and an increased VLF/HF (Very Low Frequency/High Frequency) ratio (a measure of autonomic balance), compared to those in the 2D-group, indicating that autonomic balance was not stable in the 3D-group. Additionally, a more disordered heart rhythm pattern and increasing heart rate (as determined by the R-peak to R-peak (RR) interval) was observed among subjects in the 3D-group compared to subjects in the 2D-group, further indicating that 3D viewing induces lasting activation of the sympathetic nervous system and interrupts autonomic balance.
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Affiliation(s)
- S Park
- Dept. of Emotion Engineering, Graduate School, Sangmyung University, 7 Hongji-dong, Jongro-Ku, Seoul 110-743, Republic of Korea.
| | - M J Won
- Dept. of Emotion Engineering, Graduate School, Sangmyung University, 7 Hongji-dong, Jongro-Ku, Seoul 110-743, Republic of Korea.
| | - S Mun
- Dept. of Human Computer Interaction and Robotics, University of Science and Technology, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791, Republic of Korea.
| | - E C Lee
- Dept. of Computer Science, Sangmyung University, 7 Hongji-dong, Jongro-Ku, Seoul 110-743, Republic of Korea.
| | - M Whang
- Dept. of Digital Media, Sangmyung University, 7 Hongji-dong, Jongro-Ku, Seoul 110-743, Republic of Korea.
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Whang M, Geffner S, Baimeedi S, Bonomini L, Mulgaonkar S. Urologic complications in over 1000 kidney transplants performed at the Saint Barnabas healthcare system. Transplant Proc 2003; 35:1375-7. [PMID: 12826163 DOI: 10.1016/s0041-1345(03)00519-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [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: 11/26/2022]
Abstract
We report the complication rate based on one urologist's experience over a 9-year period including over 1000 ureteral reimplants performed at the time of kidney transplantation. Among 1083 ureteral reimplant operations, there was a 4.3% urologic complication rate, including a 2.7% ureteral stricture rate and a less than 1% rate each of urine leak ureteropelvic junction obstruction, vesicoureteral reflux and clot obstruction. The factors that lead to a low urologic complication rate are believed to be the use of short ureteral segment using the Lich (compared to the Politano-Leadbetter) technique and the routine use of indwelling stents. In addition, a consistency in results was attributed to one transplant urologist performing all ureteral reimplants and managing all urologic complications.
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Affiliation(s)
- M Whang
- Division of Transplantation, Saint Barnabas Medical Center, Livingston, New Jersey 07039, USA
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Whang M, Geffner S, Khachikian Z, Kumar A, Bonomini L, Mulgaonkar S. Renal transplantation and prostate cancer: guidelines for screening and treatment. Transplant Proc 2002; 34:3196-9. [PMID: 12493418 DOI: 10.1016/s0041-1345(02)03628-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- M Whang
- Division of Transplantation, St Barnabas Medical Center, Livingston, NJ, USA
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Whang M, Katz L, Ongcapin E, Geffner S, Friedman G, Mulgaonkar S, Kaplan B. Nephrogenic adenomas occurring in a patient with simultaneous kidney-pancreas transplant. Urology 2000; 55:949. [PMID: 10840121 DOI: 10.1016/s0090-4295(00)00465-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [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: 11/18/2022]
Abstract
We present a female patient who developed multiple nephrogenic adenomas of the bladder about 3 years after a simultaneous kidney-pancreas transplant. The patient was initially treated with endoscopic resection but, due to recurrences, she later underwent a conversion of pancreatic drainage from the bladder to the small bowel and has since done well. We believe this to be the first such case reported in the literature.
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Affiliation(s)
- M Whang
- Division of Transplantation, Saint Barnabas Health Care System, St. Barnabas Medical Center, Livingston, NJ 07039, USA
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Whang M, O'Toole K, Bixon R, Brunetti J, Ikeguchi E, Olsson CA, Sawczuk TS, Benson MC. The incidence of multifocal renal cell carcinoma in patients who are candidates for partial nephrectomy. J Urol 1995; 154:968-70; discussion 970-1. [PMID: 7637103] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
PURPOSE A prospective study was performed to determine the incidence of multifocal renal cell carcinoma in patients who are candidates for partial nephrectomy. MATERIALS AND METHODS Preoperative imaging studies and surgical specimens in 44 patients suitable for partial nephrectomy but undergoing radical nephrectomy were prospectively reviewed. RESULTS Of 44 renal cell cancers 11 (25%) demonstrated pathological multifocality, while 10 of 11 multifocal tumors (91%) occurred in the face of a primary tumor 5 cm. or smaller. Tumor multifocality was independent of the size of the primary renal tumor but occurred with a slightly higher frequency in tumors of stage T3A or greater even if the primary tumor was small. CONCLUSIONS Partial nephrectomy in patients with unilateral renal cancer should be approached with caution and should not be performed simply because it is technically feasible.
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Affiliation(s)
- M Whang
- Department of Urology, Columbia University College of Physicians and Surgeons, J. Bentley Squier Urological Clinic, New York, New York, USA
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Seaman E, Whang M, Olsson CA, Katz A, Cooner WH, Benson MC. PSA density (PSAD). Role in patient evaluation and management. Urol Clin North Am 1993; 20:653-63. [PMID: 7505973] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Prostate Specific Antigen (PSA) is the most accurate serum marker for cancer of the prostate. However, sensitivity and specificity are suboptimal, especially at the intermediate levels between 4.1 and 10.0 ng/ml (monoclonal). For intermediate PSA levels, prostate specific antigen density (PSAD) provides unique information regarding the need for biopsy and the likelihood of prostate cancer. This article summarizes the utility of PSAD in diagnosing and treating prostate cancer.
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Affiliation(s)
- E Seaman
- Department of Urology, College of Physicians and Surgeons of Columbia University, New York, New York
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Fadem BH, Tesoriero JV, Whang M. Early differentiation of the gonads in the gray short-tailed opossum (Monodelphis domestica). Biol Neonate 1992; 61:131-6. [PMID: 1567932 DOI: 10.1159/000243542] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The time course for gonadal development in gray short-tailed opossums was examined in this study. It was found that the gonads were not differentiated on day 1 of postnatal life (the day of birth). While testis development was seen by postnatal day 4, ovarian development did not occur until after postnatal day 16. In both sexes, primordial germ cells were not identified until after postnatal day 1. These findings are discussed with respect to gonadal differentiation in other marsupial species.
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Affiliation(s)
- B H Fadem
- Department of Psychiatry, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark 07103
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Abstract
Chloroplasts, isolated from the primary leaves of 7-day-old seedlings, were incubated in vitro at 25 degrees C with 2-chloroethylphosphonic acid (ethephon) under light (0.16 milliwatts per square centimeter) and dark conditions. Ethephon at 1 micromolar (0.1445 ppm), 0.1 and 1 millimolar, or 5 microliters ethylene promoted the deterioration of chloroplasts, increased proteolysis, and reduced the chlorophyll content and PSI and PSII during 72 hours under both light and dark conditions. The decline in PSI and PSII occurred prior to a measurable loss of chlorophyll. The loss of photosynthetic activity affected by ethephon was initiated prior to 12 hours of incubation. After 24 hours in light, 0.1 millimolar (1.445 ppm) epthephon significantly reduced PSI and PSII and promoted the total free amino acid liberation in isolated chloroplasts. In darkness the rate of loss of PSI activity was about 50% of that in light. After 24 hours, in light at 1 millimolar epthephon, PSII activity was 55% of the control, yet nearly 90% of the chlorophyll remained, which indicates that the loss of thylakoid integrity was promoted by ethephon. Ethylene injected in the chloroplast medium at 5 microliters (0.22 micromolar per milliliter) reduced PSI by nearly 50% of the initial in 12 hours. In leaf sections floated in 5 microliters per milliliter suspension medium, a 36% loss of chlorophyll of the control in 36 hours was observed. Cycloheximide at 0.5 millimolar masked the effect of 1 millimolar ethephon and maintained the initial chlorophyll content during the 72 hour period.
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Affiliation(s)
- H T Choe
- Department of Biological Sciences, Mankato State University, Mankato, Minnesota 56001
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