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Lartey R, Nanavati A, Kim J, Li M, Xu K, Nakamura K, Shin W, Winalski CS, Obuchowski N, Bahroos E, Link TM, Hardy PA, Peng Q, Kim J, Liu K, Fung M, Wu C, Li X. Reproducibility of T 1ρ and T 2 quantification in a multi-vendor multi-site study. Osteoarthritis Cartilage 2023; 31:249-257. [PMID: 36370959 PMCID: PMC10016129 DOI: 10.1016/j.joca.2022.10.017] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 10/08/2022] [Accepted: 10/10/2022] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To evaluate the multi-vendor multi-site reproducibility of two-dimensional (2D) multi-echo spin-echo (MESE) T2 mapping (product sequences); and to evaluate the longitudinal reproducibility of three-dimensional (3D) magnetization-prepared angle-modulated partitioned k-space spoiled gradient echo snapshots (MAPSS) T1ρ and T2 mapping (research sequences), and 2D MESE T2 mapping, separated by 6 months, in a multi-vendor multi-site setting. METHODS Phantoms and volunteers (n = 5 from each site, n = 20 in total) were scanned on four 3 T magnetic resonance (MR) systems from four sites and three vendors (Siemens, General Electric, and Phillips). Two traveling volunteers (3 knees) scanned at all 4 sites at baseline and 6-month follow-up. Data was transferred to one site for centralized processing. Coefficients of variation (CVs) were calculated to evaluate reproducibility. RESULTS For baseline 2D MESE T2 measures, average CV were 0.37-2.45% (intra-site) and 5.96% (inter-site) for phantoms, and 3.15-8.49% (intra-site) and 14.16% (inter-site) for volunteers. For longitudinal phantom data, intra-site CVs were 1.42-3.48% for 3D MAPSS T1ρ, 1.77-3.56% for 3D MAPSS T2, and 1.02-2.54% for 2D MESE T2. For the longitudinal volunteer data, the intra-site CVs were 2.60-4.86% for 3D MAPSS T1ρ, 3.33-7.25% for 3D MAPSS T2, and 3.11-8.77% for 2D MESE T2. CONCLUSION This study demonstrated excellent intra-site reproducibility of 2D MESE T2 imaging, while its inter-site variation was slightly higher than 3D MAPSS T2 imaging (10.06% as previously reported). This study also showed excellent reproducibility of longitudinal T1ρ and T2 cartilage quantification, in a multi-vendor multi-site setting for both product 2D MESE T2 and 3D MAPSS T1p/T2 research sequences.
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Affiliation(s)
- R Lartey
- Program of Advanced Musculoskeletal Imaging (PAMI), Cleveland Clinic, OH, USA; Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, OH, USA
| | - A Nanavati
- Program of Advanced Musculoskeletal Imaging (PAMI), Cleveland Clinic, OH, USA; Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, OH, USA
| | - J Kim
- Program of Advanced Musculoskeletal Imaging (PAMI), Cleveland Clinic, OH, USA; Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, OH, USA
| | - M Li
- Program of Advanced Musculoskeletal Imaging (PAMI), Cleveland Clinic, OH, USA; Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, OH, USA
| | - K Xu
- Program of Advanced Musculoskeletal Imaging (PAMI), Cleveland Clinic, OH, USA; Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, OH, USA
| | - K Nakamura
- Program of Advanced Musculoskeletal Imaging (PAMI), Cleveland Clinic, OH, USA; Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, OH, USA
| | - W Shin
- Program of Advanced Musculoskeletal Imaging (PAMI), Cleveland Clinic, OH, USA; Department of Diagnostic Radiology, Imaging Institute, Cleveland Clinic, OH, USA
| | - C S Winalski
- Program of Advanced Musculoskeletal Imaging (PAMI), Cleveland Clinic, OH, USA; Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, OH, USA; Department of Diagnostic Radiology, Imaging Institute, Cleveland Clinic, OH, USA
| | - N Obuchowski
- Program of Advanced Musculoskeletal Imaging (PAMI), Cleveland Clinic, OH, USA; Quantitative Health Sciences, Lerner Research Institute, Cleveland Clinic, OH, USA
| | - E Bahroos
- Department of Radiology and Biomedical Imaging, University of California, San Francisco (UCSF), CA, USA
| | - T M Link
- Department of Radiology and Biomedical Imaging, University of California, San Francisco (UCSF), CA, USA
| | - P A Hardy
- Department of Radiology, University of Kentucky, Lexington KY, USA
| | - Q Peng
- Department of Radiology, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, NY, USA
| | - J Kim
- Arthritis Foundation, GA, USA
| | - K Liu
- Siemens Medical Solution Inc., USA
| | - M Fung
- GE Healthcare, Waukesha, WI, USA
| | - C Wu
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - X Li
- Program of Advanced Musculoskeletal Imaging (PAMI), Cleveland Clinic, OH, USA; Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, OH, USA; Department of Diagnostic Radiology, Imaging Institute, Cleveland Clinic, OH, USA.
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Labit E, Sinha S, Kutluberk E, Jaffer A, Arora R, Cao L, Shin W, Rosin N, Yipp B, Biernaskie J. 753 Preferential recruitment of immature neutrophils enables robust skin regeneration. J Invest Dermatol 2022. [DOI: 10.1016/j.jid.2022.05.766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Kim D, Shin JS, Moon YJ, Ryu G, Shin W, Lee J, Lim S, Jeon HA, Seo JY, Wang WH, Lee JH, Park KS, Lee YJ, Ha IH. Long-Term Follow-Up of Spinal Stenosis Inpatients Treated with Integrative Korean Medicine Treatment. J Clin Med 2020; 10:jcm10010074. [PMID: 33379221 PMCID: PMC7795491 DOI: 10.3390/jcm10010074] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 12/19/2020] [Accepted: 12/23/2020] [Indexed: 12/12/2022] Open
Abstract
The present prospective observational study aimed to analyze the outcomes of inpatients who received integrative Korean medicine treatment in order to provide evidence on its effects on lumbar spinal stenosis (LSS). Patients with LSS who received inpatient treatment at four Korean medicine hospitals from January 2015 to December 2018 were followed up. Outcomes measured included the numeric rating scale (NRS) scores for back and leg pain, and Oswestry Disability Index (ODI). Changes in outcomes at admission, discharge, and follow-up, as well as associated predictors that could account for the improvement in outcomes were analyzed. The NRS score for back pain, NRS score for leg pain, and ODI decreased by 2.20 points (95% confidence interval (CI), -2.41 to -1.99), 2.28 points (95% CI, -2.59 to -1.96), and 17.31 points (95% CI, -19.6 to -15.02), respectively, at long-term follow-up compared with at admission. Patients with LSS who received inpatient integrative Korean medicine treatment exhibited an improvement in pain and functional disability. Further studies are required to determine the effects of integrative Korean medicine treatment.
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Affiliation(s)
- Doori Kim
- Jaseng Spine and Joint Research Institute, Jaseng Medical Foundation, Seoul 06110, Korea; (D.K.); (K.S.P.); (Y.J.L.)
| | - Joon-Shik Shin
- Jaseng Hospital of Korean Medicine, Seoul 06110, Korea; (J.-S.S.); (J.-H.L.)
| | - Young-Joo Moon
- Bucheon Jaseng Hospital of Korean Medicine, Bucheon 14598, Korea; (Y.-J.M.); (G.R.); (W.S.); (J.L.); (S.L.); (H.A.J.); (J.-Y.S.); (W.H.W.)
| | - Gwanghyun Ryu
- Bucheon Jaseng Hospital of Korean Medicine, Bucheon 14598, Korea; (Y.-J.M.); (G.R.); (W.S.); (J.L.); (S.L.); (H.A.J.); (J.-Y.S.); (W.H.W.)
| | - Wonbin Shin
- Bucheon Jaseng Hospital of Korean Medicine, Bucheon 14598, Korea; (Y.-J.M.); (G.R.); (W.S.); (J.L.); (S.L.); (H.A.J.); (J.-Y.S.); (W.H.W.)
| | - Jiyun Lee
- Bucheon Jaseng Hospital of Korean Medicine, Bucheon 14598, Korea; (Y.-J.M.); (G.R.); (W.S.); (J.L.); (S.L.); (H.A.J.); (J.-Y.S.); (W.H.W.)
| | - Suyeon Lim
- Bucheon Jaseng Hospital of Korean Medicine, Bucheon 14598, Korea; (Y.-J.M.); (G.R.); (W.S.); (J.L.); (S.L.); (H.A.J.); (J.-Y.S.); (W.H.W.)
| | - Hyun A Jeon
- Bucheon Jaseng Hospital of Korean Medicine, Bucheon 14598, Korea; (Y.-J.M.); (G.R.); (W.S.); (J.L.); (S.L.); (H.A.J.); (J.-Y.S.); (W.H.W.)
| | - Ji-Yeon Seo
- Bucheon Jaseng Hospital of Korean Medicine, Bucheon 14598, Korea; (Y.-J.M.); (G.R.); (W.S.); (J.L.); (S.L.); (H.A.J.); (J.-Y.S.); (W.H.W.)
| | - Wu Hao Wang
- Bucheon Jaseng Hospital of Korean Medicine, Bucheon 14598, Korea; (Y.-J.M.); (G.R.); (W.S.); (J.L.); (S.L.); (H.A.J.); (J.-Y.S.); (W.H.W.)
| | - Jin-Ho Lee
- Jaseng Hospital of Korean Medicine, Seoul 06110, Korea; (J.-S.S.); (J.-H.L.)
| | - Kyoung Sun Park
- Jaseng Spine and Joint Research Institute, Jaseng Medical Foundation, Seoul 06110, Korea; (D.K.); (K.S.P.); (Y.J.L.)
- Jaseng Hospital of Korean Medicine, Seoul 06110, Korea; (J.-S.S.); (J.-H.L.)
| | - Yoon Jae Lee
- Jaseng Spine and Joint Research Institute, Jaseng Medical Foundation, Seoul 06110, Korea; (D.K.); (K.S.P.); (Y.J.L.)
| | - In-Hyuk Ha
- Jaseng Spine and Joint Research Institute, Jaseng Medical Foundation, Seoul 06110, Korea; (D.K.); (K.S.P.); (Y.J.L.)
- Correspondence: ; Tel.: +82-2-2222-2740
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Blacksburg S, Sheu R, Carpenter T, Repka M, Demircioglu G, Witten M, Mendez C, Auto H, Shin W, Zafar S, Ilyas A, Haas J. Obstructive Uropathy after Prostate SBRT is Rare: Characterizing Clinical and Dosimetric Predictors From a Large Patient Cohort. Int J Radiat Oncol Biol Phys 2020. [DOI: 10.1016/j.ijrobp.2020.07.452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Eum H, Lee Y, Shin W, Jung H, Kwon M, Shim J, KIM D. PDB28 A Real-World Effectiveness of Udca Added to Oha on Glycemic Control in Type 2 Diabetes Patients with LIVER Disease. Value Health Reg Issues 2020. [DOI: 10.1016/j.vhri.2020.07.187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Kim D, Shin W, Byun J. 1197 Utility of Fitbit Charge 2 for Sleep Monitoring in Patients With Obstructive Sleep Apnea. Sleep 2020. [DOI: 10.1093/sleep/zsaa056.1191] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Introduction
The wearable device may be useful in monitoring sleep. Many studies reported reliable data in detecting sleep-wake states and sleep stage proportion in healthy adults, However, only a few validation studies were performed evaluating sleep using the wearable devices in patients with obstructive sleep apnea(OSA), which showed insufficient accuracy. We aimed to evaluate the reliability of multi-sensory wristband (Fitbit Charge 2) in patients with OSA.
Methods
This was a preliminary analysis of a prospective single-center observational study. Consecutive patients underwent standard Polysomnography (PSG) for evaluation of OSA with Fitbit Charge 2. Sleep data from PSG and Fitbit charge 2 were compared using paired t-tests and Bland-Altman plots.
Results
A total of eighty-six patients were analyzed. Four of them had poor data quality, 18 of them did not show sleep stages. Compared with the PSG, Fitbit Charge 2 showed higher total sleep time (419.1±194.0 vs 269.8±22.6, p<0.001) and sleep efficiency (95.8±2.5 vs 84.6±7.1, p<0.001). Those with sleep stage data showed higher sleep efficacy (87.7±5.5 vs 82.37.5, p=0.024) and a lower proportion of N1 sleep (33.7±19.9 vs 65.3±38.8, p=0.01).
Conclusion
Fitbit Charge 2 showed limited utility in monitoring sleep in patients with obstructive sleep apnea.
Support
none
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Affiliation(s)
- D Kim
- KyungHee University Hospital at Gangdong, Seoul, KOREA, REPUBLIC OF
| | - W Shin
- KyungHee University Hospital at Gangdong, Seoul, KOREA, REPUBLIC OF
| | - J Byun
- KyungHee University Hospital at Gangdong, Seoul, KOREA, REPUBLIC OF
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Shin W, Byun J. Efficacy of prolonged-release melatonin versus clonazepam for REM sleep without atonia in patients with newly diagnosed idiopathic REM sleep behavior disorder. J Neurol Sci 2019. [DOI: 10.1016/j.jns.2019.10.1806] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [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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Park J, Shin W. Posterior reversible encephalopathy syndrome after massive transfusion in a patient with postpartum vaginal hematoma. J Neurol Sci 2019. [DOI: 10.1016/j.jns.2019.10.1478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Chung S, Kim K, Shin W, Seong J. Determining and Incorporating the Optimal Predictive Biomarkers in Hepatocellular Carcinoma Patients Treated with Radiotherapy. Int J Radiat Oncol Biol Phys 2019. [DOI: 10.1016/j.ijrobp.2019.06.607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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10
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Shin W, Noh J, Lim M, Kang S, Seo S, Lee K, Kim B, Park S. The prognosis of epithelial ovarian cancer patients who are refractory after neoadjuvant chemotherapy. Gynecol Oncol 2019. [DOI: 10.1016/j.ygyno.2019.04.543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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11
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Shin W, Rosin N, Sparks H, Sinha S, Rahmani W, Workentine M, Abbasi S, Stratton J, Biernaskie J. 905 Dysfunction of hair follicle mesenchymal progenitors is associated with age-related hair loss. J Invest Dermatol 2019. [DOI: 10.1016/j.jid.2019.03.981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Shin Y, Byun J, Ahn S, Yang K, Cho Y, Shin W. 0554 Efficacy Of Dental Device For Treatment For Moderate To Severe Obstructive Sleep Apnea In Korean: Interim Result Of Prospective Multi-center Study. Sleep 2018. [DOI: 10.1093/sleep/zsy061.553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Y Shin
- Kyung-Hee University Hospital at Gangdong, Seoul, KOREA, REPUBLIC OF
| | - J Byun
- Kyung-Hee University Hospital at Gangdong, Seoul, KOREA, REPUBLIC OF
| | - S Ahn
- Kyung-Hee University Hospital at Gangdong, Seoul, KOREA, REPUBLIC OF
| | - K Yang
- SOON CHUN HYANG University Hospital Cheonan, Cheonan, KOREA, REPUBLIC OF
| | - Y Cho
- Keimyung University Dongsan Medical Center, Daegu, KOREA, REPUBLIC OF
| | - W Shin
- Kyung-Hee University Hospital at Gangdong, Seoul, KOREA, REPUBLIC OF
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Chung S, Byun J, Shin Y, Shin W. 0502 Alternative Stop-bang Questionnaire Scoring Criteria To Detect Obstructive Sleep Apnea In Korean Population. Sleep 2018. [DOI: 10.1093/sleep/zsy061.501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- S Chung
- Kyung-Hee University Hospital at Gangdong, Seoul, KOREA, REPUBLIC OF
| | - J Byun
- KyungHee University Hospital at Gangdong, Seoul, KOREA, REPUBLIC OF
| | - Y Shin
- KyungHee University Hospital at Gangdong, Seoul, KOREA, REPUBLIC OF
| | - W Shin
- KyungHee University Hospital at Gangdong, Seoul, KOREA, REPUBLIC OF
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Han K, Kim M, Lee D, Won J, Park S, Kim G, Joon Ho K, Shin W. Hybrid treatment expanding the armamentarium for infected infrarenal abdominal aortic and iliac aneurysms. J Vasc Interv Radiol 2017. [DOI: 10.1016/j.jvir.2016.12.1017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Hida T, Oya Y, Tanaka K, Yoshida T, Shimizu J, Horio Y, Yatabe Y, Itoh T, Shin W. 12P Volatolomic signatures of anaplastic lymphoma kinase gene rearrangement in adenocarcinoma. J Thorac Oncol 2016. [DOI: 10.1016/s1556-0864(16)30126-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Choi H, Shin W, Kim J, Testa M, Min C. SU-E-T-427: Feasibility Study for Evaluation of IMRT Dose Distribution Using Geant4-Based Automated Algorithms. Med Phys 2015. [DOI: 10.1118/1.4924788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Affiliation(s)
- E. Han
- Biopharmaceuticals and Herbal Medicines Evaluation Department; Korea Ministry of Food and Drug Safety; Cheongju-si Korea
| | - W. Shin
- Biopharmaceuticals and Herbal Medicines Evaluation Department; Korea Ministry of Food and Drug Safety; Cheongju-si Korea
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Banks SJ, Obuchowski N, Shin W, Lowe M, Phillips M, Modic M, Bernick C. The Protective Effect of Education on Cognition in Professional Fighters. Arch Clin Neuropsychol 2013; 29:54-9. [DOI: 10.1093/arclin/act079] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Shin W, Mahmoud SY, Sakaie K, Banks SJ, Lowe MJ, Phillips M, Modic MT, Bernick C. Diffusion measures indicate fight exposure-related damage to cerebral white matter in boxers and mixed martial arts fighters. AJNR Am J Neuroradiol 2013; 35:285-90. [PMID: 23928146 DOI: 10.3174/ajnr.a3676] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Traumatic brain injury is common in fighting athletes such as boxers, given the frequency of blows to the head. Because DTI is sensitive to microstructural changes in white matter, this technique is often used to investigate white matter integrity in patients with traumatic brain injury. We hypothesized that previous fight exposure would predict DTI abnormalities in fighting athletes after controlling for individual variation. MATERIALS AND METHODS A total of 74 boxers and 81 mixed martial arts fighters were included in the analysis and scanned by use of DTI. Individual information and data on fight exposures, including number of fights and knockouts, were collected. A multiple hierarchical linear regression model was used in region-of-interest analysis to test the hypothesis that fight-related exposure could predict DTI values separately in boxers and mixed martial arts fighters. Age, weight, and years of education were controlled to ensure that these factors would not account for the hypothesized effects. RESULTS We found that the number of knockouts among boxers predicted increased longitudinal diffusivity and transversal diffusivity in white matter and subcortical gray matter regions, including corpus callosum, isthmus cingulate, pericalcarine, precuneus, and amygdala, leading to increased mean diffusivity and decreased fractional anisotropy in the corresponding regions. The mixed martial arts fighters had increased transversal diffusivity in the posterior cingulate. The number of fights did not predict any DTI measures in either group. CONCLUSIONS These findings suggest that the history of fight exposure in a fighter population can be used to predict microstructural brain damage.
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Affiliation(s)
- W Shin
- From the Imaging Institute (W.S., S.Y.M., K.S., M.J.L., M.P.)
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Siver PA, Wolfe AP, Rohlf FJ, Shin W, Jo BY. Combining geometric morphometrics, molecular phylogeny, and micropaleontology to assess evolutionary patterns in Mallomonas (Synurophyceae: Heterokontophyta). Geobiology 2013; 11:127-138. [PMID: 23331313 DOI: 10.1111/gbi.12023] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Accepted: 11/21/2012] [Indexed: 06/01/2023]
Abstract
Synurophytes, also known as scaled chrysophytes, are ecologically important algae that produce an array of siliceous structures upon which their taxonomy is based. Despite occupying a key position within the photosynthetic heterokonts, the evolutionary history of synurophytes remains poorly constrained. Here, modern and Middle Eocene siliceous scales of the morphotaxon Mallomonas insignis are used as a model to investigate synurophyte evolutionary patterns. Structural details of scale morphology were examined comparatively with scanning electron microscopy and scored for geometric morphometric analyses to assess the stability of shape characters. Although consistent size differences exist (modern scales are larger than Eocene counterparts), the populations cannot be differentiated on the basis of shape or microstructural detail, implying considerable evolutionary stasis in scale morphology. A time-calibrated relaxed molecular clock analysis using a three-gene concatenated data set (27 strains) suggests that the M. insignis lineage predates the available fossil record, having diverged from closest congeneric taxa in the Cretaceous (≥94 Ma). However, the molecular analysis also implies that considerable genetic variability is present within several morphotaxa of Mallomonas, implying that substantial genetic variability has arisen despite the retention of uniform scale morphologies, and resulting in the widespread occurrence of cryptic taxa. Results from the synurophyte lineage are consistent with the notion of protracted ghost ranges (>10 Ma) implied by the molecular phylogenies of other algal groups, together pointing to the paucity of the fossil record of these organisms on these timescales.
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Affiliation(s)
- P A Siver
- Department of Botany, Connecticut College, New London, CT, USA
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Jung C, Shin W, Yu BA, Lee YL, Noh YC. Enhanced 355-nm generation using a simple method to compensate for walk-off loss. Opt Express 2012; 20:941-948. [PMID: 22274441 DOI: 10.1364/oe.20.000941] [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: 05/31/2023]
Abstract
We theoretically and experimentally investigated a novel walk-off-compensation method for efficient ultraviolet beam generation. Through theoretical investigation, we described in detail how the power of a generated UV beam can be enhanced by the method; thus, we obtained a brief expression for the output power which has a prediction error of about 30%. In addition, we found that the beam quality can also be enhanced using this method. Through experiments using an alpha barium borate crystal as a walk-off compensator, we found that the power of the generated ultraviolet beam increased 1.9 times.
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Affiliation(s)
- C Jung
- Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Buk-gu, Gwangju, South Korea
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Shin W, Nishibori M, Izu N, Itoh T, Matsubara I, Nose K, Shimouchi A. Monitoring Breath Hydrogen Using Thermoelectric Sensor. ACTA ACUST UNITED AC 2011. [DOI: 10.1166/sl.2011.1591] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Lee YL, Shin W, Yu BA, Jung C, Noh YC, Ko DK. Mode tailoring in a ridge-type periodically poled lithium niobate waveguide. Opt Express 2010; 18:7678-7684. [PMID: 20588608 DOI: 10.1364/oe.18.007678] [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: 05/29/2023]
Abstract
We present a simple and powerful method for mode generation and transformation in a ridge-type periodically poled lithium niobate (PPLN) waveguide by the use of second-order nonlinear effect and local-temperature-control technique. We show that a Hermite-Gaussian (HG) mode wave (among HG(00) to HG(22)) can be selectively generated via the quasi-phase-matching (QPM) nonlinear process in a PPLN waveguide by tuning the wavelength of fundamental wave or the temperature of the waveguide. As well, it is demonstrated that HG mode can be transformed into Laguerre-Gaussian (LG) one via combination of HG modes which are simultaneously generated in a single PPLN waveguide with local-temperature-control technique.
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Affiliation(s)
- Y L Lee
- Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, 1 Oryong-dong, Buk-gu, Gwangju 500-712, Republic of Korea.
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Shin W, Geng X, Gu H, Yang Y. A New Brain Tissue Segmentation Algorithm Using Quantitative T1. Neuroimage 2009. [DOI: 10.1016/s1053-8119(09)71148-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Lee YL, Eom TJ, Shin W, Yu BA, Ko DK, Kim WK, Lee HY. Characteristics of a multi-mode interference device based on Ti:LiNbO3 channel waveguide. Opt Express 2009; 17:10718-10724. [PMID: 19550468 DOI: 10.1364/oe.17.010718] [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] [Indexed: 05/28/2023]
Abstract
We have analyzed the multi-mode interference effect depending on the wavelength and the polarization states of input beam in a multi-mode Ti:LiNbO(3) waveguide at about 1300 nm region. The transmitted optical signal of a Ti:LiNbO(3) waveguide shows the periodic oscillation as a function of input wavelength. The measured average periodicity of the oscillation in TM and TE polarization beams were about 18 nm and 48 nm, respectively. Actually, the periodicity is determined by the refractive index difference between the two modes (fundamental and first modes). Therefore, we have explained the experimental results with the theoretical calculations which are derived from a quasi-analytical technique based on the effective-refractive- index method and the equation of coupling length determined by the mode phase factor in the multi-mode waveguide.
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Affiliation(s)
- Y L Lee
- Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Buk-gu, Gwangju, Republic of Korea.
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Lee YL, Yu NE, Kee CS, Ko DK, Lee J, Yu BA, Shin W, Eom TJ, Noh YC. Wavelength filtering characteristics of Solc filter based on Ti:PPLN channel waveguide. Opt Lett 2007; 32:2813-5. [PMID: 17909582 DOI: 10.1364/ol.32.002813] [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: 05/17/2023]
Abstract
We have analyzed the Solc filtering characteristics in a periodically poled Ti:LiNbO3 (Ti:PPLN) multimode waveguide. The single- and dual-wavelength filtering were achieved under the optimized guiding condition for the TEM(00)-like mode and two mode (TEM(00)- and TEM(01)-like mode), respectively. The full width at half-maximum of the filter was about 0.21 nm at both guiding conditions. We found that the origin of two peaks of the dual-wavelength Solc filter in the two-mode guiding condition is the different effective refractive index between the TEM(00)- and TEM(01)-like modes. The wavelength difference of two peaks is about 0.8 nm at room temperature.
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Affiliation(s)
- Y L Lee
- Nonlinear Optics Lab, Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Korea.
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Shaibani A, Khawar S, Shin W, Cashen TA, Schirf B, Rohany M, Kakodkar S, Carroll TJ. First results in an MR imaging--compatible canine model of acute stroke. AJNR Am J Neuroradiol 2006; 27:1788-93. [PMID: 16971637 PMCID: PMC8139778] [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: 05/11/2023]
Abstract
BACKGROUND AND PURPOSE The purpose of this work was to develop an MR imaging-compatible animal model of reversible embolic stroke. We hypothesize that real-time MR imaging of the brain can be performed during stroke thrombolysis and can provide real-time feedback and guidance on the success of thrombolysis. METHODS Embolic strokes were induced in 5 adult dogs by the use of autologous blood clots, with a sixth dog serving as an experimental control. Serial MR anatomic and physiologic imaging was performed to track the evolution of the stroke. The apparent diffusion coefficient (ADC) and quantitative cerebral blood flow (qCBF) were compared in the normal and stroke regions. During and after the administration of a chemical thrombolytic agent, MR imaging was performed to assess the outcome of the treatment. RESULTS Strokes were successfully created in 5 animals. No ADC or qCBF changes were observed in the control animal. Both ADC and qCBF values were found to be significantly different in the region affected by the stroke. Restoration of flow was observed in 1 case. CONCLUSION We have successfully implemented an MR imaging-compatible canine model of reversible embolic stroke.
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Affiliation(s)
- A Shaibani
- Department of Radiology, Northwestern University, Chicago, IL 60611, USA
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Cashen TA, Carr JC, Shin W, Walker MT, Futterer SF, Shaibani A, McCarthy RM, Carroll TJ. Intracranial time-resolved contrast-enhanced MR angiography at 3T. AJNR Am J Neuroradiol 2006; 27:822-9. [PMID: 16611772 PMCID: PMC8133971] [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: 05/08/2023]
Abstract
BACKGROUND AND PURPOSE A method is presented for high-temporal-resolution MR angiography (MRA) using a combination of undersampling strategies and a high-field (3T) scanner. Currently, the evaluation of cerebrovascular disorders involving arteriovenous shunting or retrograde flow is accomplished with conventional radiographic digital subtraction angiography, because of its high spatial and temporal resolutions. Multiphase MRA could potentially provide the same diagnostic information noninvasively, though this is technically challenging because of the inherent trade-off between signal intensity-to-noise ratio (S/N), spatial resolution, and temporal resolution in MR imaging. METHODS Numerical simulations addressed the choice of imaging parameters at 3T to maximize S/N and the data acquisition rate while staying within specific absorption rate limits. The increase in S/N at 3T was verified in vivo. An imaging protocol was developed with S/N, spatial resolution, and temporal resolution suitable for intracranial angiography. Partial Fourier imaging, parallel imaging, and the time-resolved echo-shared acquisition technique (TREAT) were all used to achieve sufficient undersampling. RESULTS In 40 volunteers and 10 patients exhibiting arteriovenous malformations or fistulas, intracranial time-resolved contrast-enhanced MRA with high acceleration at high field produced diagnostic-quality images suitable for assessment of pathologies involving arteriovenous shunting or retrograde flow. The technique provided spatial resolution of 1.1 x 1.1 x 2.5 mm and temporal resolution of 2.5 seconds/frame. The combination of several acceleration methods, each with modest acceleration, can provide a high overall acceleration without the artifacts of any one technique becoming too pronounced. CONCLUSION By taking advantage of the increased S/N provided by 3T magnets over conventional 1.5T magnets and converting this additional S/N into higher temporal resolution through acceleration strategies, intracranial time-resolved MRA becomes feasible.
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Affiliation(s)
- T A Cashen
- Department of Biomedical Engineering, Northwestern University, Feinberg School of Medicine of Northwestern University, Chicago, IL, USA
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Shin W, Han S, Park C, Oh K. All fiber optical inter-band router for broadband wavelength division multiplexing. Opt Express 2004; 12:1815-1822. [PMID: 19475011 DOI: 10.1364/opex.12.001815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We propose a new type of all-fiber device for inter-band router using a novel hybrid waveguide-MEMS technology. Both continuous and discrete band-routing functions are realized by precise twist control over the fused coupling region, which results in pi phase shift between the output ports. Experimentally we demonstrate inter-band routing functions between O and C-band as well as between E and L-band with a low insertion loss, wide bandwidth of operation, high channel isolation and fast response.
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Shin W, Choi S, Oh K. All-fiber wavelength- and mode-selective coupler for optical interconnections. Opt Lett 2002; 27:1884-1886. [PMID: 18033390 DOI: 10.1364/ol.27.001884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We experimentally demonstrate a new wavelength- and mode-selective coupler utilizing intermodal coupling between a standard single-mode fiber (SMF) and a hollow optical fiber (HOF). The fabricated device routes optical signals such that a 1.3-microm signal is directed to the HOF port, adiabatically converting the LP(01) mode into a ring-shaped mode, which can be further connected to a gigabit ethernet link, reducing the differential mode-dispersion penalty. Optical signals near 1.5microm , meanwhile, stay in the LP(01) mode of the SMF arm for further connection to conventional wavelength-division multiplexing links based on erbium-doped fiber amplifiers. The performance of the device is characterized in terms of insertion loss, channel isolation, and mode-conversion efficiency.
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Cho SW, Lee S, Shin W. The X-ray structure of Aspergillus aculeatus polygalacturonase and a modeled structure of the polygalacturonase-octagalacturonate complex. J Mol Biol 2001; 311:863-78. [PMID: 11518536 DOI: 10.1006/jmbi.2001.4919] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.3] [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: 11/22/2022]
Abstract
Polygalacturonases hydrolyze the alpha-(1-4) glycosidic bonds of de-esterified pectate in the smooth region of the plant cell wall. Crystal structures of polygalacturonase from Aspergillus aculeatus were determined at pH 4.5 and 8.5 both to 2.0 A resolution. A. aculeatus polygalacturonase is a glycoprotein with one N and ten O-glycosylation sites and folds into a right-handed parallel beta-helix. The structures of the three independent molecules are essentially the same, showing no dependency on pH or crystal packing, and are very similar to that of Aspergillus niger polygalacturonase. However, the structures of the long T1 loop containing a catalytic tyrosine residue are significantly different in the two proteins. A three-dimensional model showing the substrate binding mode for a family 28 hydrolase was obtained by a combined approach of flexible docking, molecular dynamics simulations, and energy minimization. The octagalacturonate substrate was modeled as an unbent irregular helix with the -1 ring in a half-chair ((4)H(3)) form that approaches the transition state conformation. A comparative modeling of the three polygalacturonases with known structure shows that six subsites ranging from -4 to +2 are clearly defined but subsites -5 and +3 may or may not be shaped depending on the nearby amino acid residues. Both distal subsites are mostly exposed to the solvent region and have weak binding affinity even if they exist. The complex model provides a clear explanation for the functions, either in catalysis or in substrate binding, of all conserved amino acid residues in the polygalacturonase family of proteins. Modeling suggests that the role of the conserved Asn157 and Tyr270, which had previously been unidentified, may be in transition state stabilization. In A. niger polygalacturonase, the long T1 loop may have to undergo conformational change upon binding of the substrate to bring the tyrosine residue close to subsite -1.
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Affiliation(s)
- S W Cho
- School of Chemistry and Molecular Engineering, and Center for Molecular Catalysis, Seoul National University, Seoul, 151-742, Korea
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Cho SW, Kim N, Choi MU, Shin W. Structure of aspergillopepsin I from Aspergillus phoenicis: variations of the S1'-S2 subsite in aspartic proteinases. Acta Crystallogr D Biol Crystallogr 2001; 57:948-56. [PMID: 11418762 DOI: 10.1107/s0907444901005972] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2000] [Accepted: 04/05/2001] [Indexed: 11/11/2022]
Abstract
The crystal structure of aspergillopepsin I (AP) from Aspergillus phoenicis has been determined at 2.18 A resolution and refined to R and R(free) factors of 21.5 and 26.0%, respectively. AP has the typical two beta-barrel domain structure of aspartic proteinases. The structures of the two independent molecules are partly different, exemplifying the flexible nature of the aspartic proteinase structure. Notably, the 'flap' in one molecule is closer, with a largest separation of 4.0 A, to the active site than in the other molecule. AP is most structurally homologous to penicillopepsin (PP) and then to endothiapepsin (EP), which share sequence identities of 68 and 56%, respectively. However, AP is similar to EP but differs from PP in the combined S1'-S2 subsite that is delineated by a flexible psi-loop in the C-terminal domain. The S1' and S2 subsites are well defined and small in AP, while there is no definite border between S1' and S2 and the open space for the S2 subsite is larger in PP. Comparison of the structures indicates that the two amino-acid residues equivalent to Leu295 and Leu297 of AP are the major determining factors in shaping the S1'-S2 subsite in the fungal aspartic proteinases.
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Affiliation(s)
- S W Cho
- School of Chemistry and Molecular Engineering, Seoul National University, South Korea
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Nam W, Lim MH, Oh SY, Lee JH, Lee HJ, Woo SK, Kim C, Shin W. Remarkable Anionic Axial Ligand Effects of Iron(III) Porphyrin Complexes on the Catalytic Oxygenations of Hydrocarbons by H(2)O(2) and the Formation of Oxoiron(IV) Porphyrin Intermediates by m-Chloroperoxybenzoic Acid This work was supported by Center for Cell Signaling Research (1999-2-122-002-4), the Korean Research Foundation (KRF-99-042-D00068), and the MOST through the Women's University Research Fund (99-N6-01-01-A-07). Angew Chem Int Ed Engl 2000; 39:3646-3649. [PMID: 11091426 DOI: 10.1002/1521-3773(20001016)39:20<3646::aid-anie3646>3.0.co;2-q] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- W Nam
- Department of Chemistry and Division of Molecular Life Sciences Ewha Womans University, Seoul 120-750 (Korea)
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Oh YK, Moon J, Lee JY, Cho SW, Shin W, Suh SW. Overexpression, crystallization and preliminary X-ray crystallographic analysis of dihydrofolate reductase from bacteriophage T4. Acta Crystallogr D Biol Crystallogr 2000; 56:775-7. [PMID: 10818362 DOI: 10.1107/s0907444900005266] [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: 02/16/2023]
Abstract
Dihydrofolate reductase (DHFR) from bacteriophage T4 is a homodimer consisting of 193-residue subunits. It has been crystallized in the presence of the cofactor (NADPH) and an inhibitor (aminopterin) at 296 K using sodium chloride as precipitant. The crystals are tetragonal, belonging to the space group P4(1)22 (or P4(3)22), with unit-cell parameters a = b = 61.14, c = 123.23 A under cryogenic conditions. The asymmetric unit contains a single subunit, with a corresponding V(m) of 2.65 A(3) Da(-1) and a solvent content of 53. 6%. Native data have been collected from a crystal to 1.9 A resolution using synchrotron X-rays.
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Affiliation(s)
- Y K Oh
- Department of Chemistry, College of Natural Sciences, Seoul National University, South Korea
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Cho SW, Cho Y, Kim DK, Shin W. cis-[(4R,5R)-4,5-bis(aminomethyl)-2,2-dimethyl-1,3-dioxolane-N,N']- (malonato-O,O')platinum(II), an anticancer agent. Acta Crystallogr C 2000; 56:653-4. [PMID: 10902008 DOI: 10.1107/s0108270100003577] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2000] [Accepted: 03/07/2000] [Indexed: 11/11/2022] Open
Affiliation(s)
- S W Cho
- School of Chemistry & Molecular Engineering, Seoul National University, Korea
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Yoon JW, Yoon TS, Lee SW, Shin W. (1R,2R)-(–)-[Bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediamine]chloromanganese(III), an (R,R)-Jacobsen catalyst. Acta Crystallogr C 1999. [DOI: 10.1107/s0108270199009397] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Heo YS, Yi KY, Yoo SE, Shin W. A non-peptide angiotensin II receptor antagonist: 2-butyl-6-methyl-5-(1-oxopyrid-2-yl)-1-{[2'-(1 H-tetrazol-5-yl)biphenyl-4-yl]methyl}-1 H-imidazo[5,4- b]pyridine methanol solvate. Acta Crystallogr C 1999. [DOI: 10.1107/s0108270199004679] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Yoon TS, Yoo SE, Shin W. N-(2-Dimethoxymethyl-3-hydroxy-2-methyl-6-nitro-3,4-dihydro-2 H-1-benzopyran-4-yl)acetamide. Acta Crystallogr C 1998. [DOI: 10.1107/s0108270198000250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Yoon JW, Yoon TS, Shin W. (1R,2R)-(−)-N,N'-Bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediamine: a Salen Ligand of Jacobsen's Catalyst. Acta Crystallogr C 1997. [DOI: 10.1107/s0108270197006379] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Shin W, Chae CH, Yoo SE. Antihypertensive 2-(1,3-Dioxolan-2-yl)-2-methyl-6-nitro-4-(2-oxo-1-pyrrolidinyl)-2H-1-benzopyran. Acta Crystallogr C 1996. [DOI: 10.1107/s010827019600248x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Shin W, Yoon TS, Yoo SE. A non-peptide angiotensin II receptor antagonist: 2-butyl-6-dimethoxymethyl-5-phenyl-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4- yl]methyl]-1H-imidazo[5,4-b]pyridine. Acta Crystallogr C 1996; 52 ( Pt 4):1019-22. [PMID: 8624236 DOI: 10.1107/s0108270195011978] [Citation(s) in RCA: 7] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The title compound, C33H33N7O2, is one of a series of imidazo[4,5-b]pyridine-based angiotensin II receptor antagonists showing high antihypertensive activity. The biphenyltetrazole moiety assumes the same conformation as in related compounds, but its relative orientation with respect to the central fused ring is different to that in these compounds, indicating that there is considerable conformational flexibility about the methylene bridge joining the two ring systems.
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Affiliation(s)
- W Shin
- Department of Chemistry, Seoul National University, Korea
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Xu F, Shin W, Brown SH, Wahleithner JA, Sundaram UM, Solomon EI. A study of a series of recombinant fungal laccases and bilirubin oxidase that exhibit significant differences in redox potential, substrate specificity, and stability. Biochim Biophys Acta 1996; 1292:303-11. [PMID: 8597577 DOI: 10.1016/0167-4838(95)00210-3] [Citation(s) in RCA: 367] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A series of fungal laccases (Polyporus pinsitus, Rhizoctonia solani, Myceliophthora thermophila, Scytalidium thermophilum) and one bilirubin oxidase (Myrothecium verrucaria) have been studied to determine their redox potential, specificity, and stability. Polyporus and Rhizoctonia laccases possess potentials near 0.7-0.8 V (vs. NHE), while other oxidases have potentials near 0.5 V. It is observed that higher redox potential correlates with higher activity. By EPR, no significant change in the geometry of type 1 copper (II) site is observed over this series. At the optimal pH, the two substrates studied, 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulfonic acid) and syringaldazine, show Km values ranging form 10 to 120 and from 1 to 45 microM; and kcat values ranging from 50 to 16 000 and 200 to 3000 per min, respectively. The enzymes are more stable in the neutral-alkaline pH range. The thermal stability is in the order of bilirubin oxidase equivalent to Myceliophthora laccase equivalent to Scytalidium laccase > Polyporus laccase > Rhizoctonia laccase. Based on these results and the sequence alignments made against Zucchini ascorbate oxidase it is speculated that structural differences in the substrate-activation site (a 'blue', type 1 copper center) control the redox potential range as well as substrate specificity, and the cystine content contributes to stability.
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Affiliation(s)
- F Xu
- Novo Nordisk Biotech, Davis, CA 95616 USA
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Shin W, Kim SJ, Shin JM, Kim SH. Structure-taste correlations in sweet dihydrochalcone, sweet dihydroisocoumarin, and bitter flavone compounds. J Med Chem 1995; 38:4325-31. [PMID: 7473560 DOI: 10.1021/jm00021a022] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [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: 01/25/2023]
Abstract
The dihydrochalcone derivatives of the bitter flavonoids naringin and neohesperedin are intensely sweet. Phyllodulcin is as sweet as the dihydrochalcones with similar taste properties although its structure apparently resembles that of bitter flavanone or flavone. Multifaceted approaches, including X-ray crystal structure analysis, energy calculation, and structure comparison, have been employed to clarify the structure-taste correlations in these classes of compounds. In the crystal, naringin dihydrochalcone assumes a 'J'-shaped conformation with a fully-extended dihydrochalcone moiety while neohesperidin dihydrochalcone assumes the same overall conformation but with a partially-extended moiety. A 2D conformational energy map of dihydrochalcone obtained using molecular mechanics revealed nine local minima. The pseudoequatorial and pseudoaxial forms of phyllodulcin have the same AM1 energies with a low energy barrier between them. The partially-extended form of dihydrochalcone and the pseudoequatorial form of phyllodulcin which are the maximally superposable conformers are proposed to be the active conformers. The major difference between the structures of flavone and phyllodulcin is not in the overall planarity but in the relative orientation of the pyrone and phenyl ring systems.
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Affiliation(s)
- W Shin
- Department of Chemistry, Seoul National University, Korea
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Shin W, Lim BC. Thiamin Thiothiazolone Acetone Solvate, C12H16N4OS2.0.5C3H6O. Acta Crystallogr C 1995. [DOI: 10.1107/s0108270194003811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Abstract
Composite restorative materials wear by a fatigue mechanism in the occlusal contact area. Here, tooth cusps and food debris cyclically indent the restoration. Modeling this phenomenon requires an understanding of material response to indentation. The question in this study was whether material response depends on indenter size and geometry, and also, whether polymers used in restorative materials should be considered elastic and brittle, or plastic and ductile for modeling purposes. Three resins used as matrices in proprietary restorative composites were the experimental materials. To ascertain the influence of glass transition temperature, liquid sorption, and small amounts of filler on indentation response, we prepared materials with various degrees of cure; some samples were soaked in a 50/50 water/ethanol solution, and 3 vol% silica was added in some cases. Indentation experiments revealed that no cracking occurred in any material after indentation by Vickers pyramid or spherical indenters with diameters equal to or smaller than 0.254 mm. Larger spherical indenters induced subsurface median and surface radial and/or ring cracks. Critical loads causing subsurface cracks were measured. Indentation with suitably large spherical indenters provoked an elastoplastic response in polymers, and degree of cure and Tg had less influence on critical load than soaking in solution. Crack morphology was correlated with yield strain. Commonly held assumptions regarding the brittle elastic behavior of composite matrix materials may be incorrect.
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Affiliation(s)
- G Baran
- Temple University, Philadelphia, Pennsylvania 19140
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Shin W, Lindahl PA. Low spin quantitation of NiFeC EPR signal from carbon monoxide dehydrogenase is not due to damage incurred during protein purification. Biochim Biophys Acta 1993; 1161:317-22. [PMID: 8381672 DOI: 10.1016/0167-4838(93)90231-f] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Evidence is presented that the O2-sensitive, nickel- and iron-containing enzyme carbon monoxide dehydrogenase from Clostridium thermoaceticum was purified without significantly inactivating either its CO oxidation or CO/acetyl-CoA exchange activities. All CO oxidation activity from the crude extract was recovered in the purified enzyme (and side fractions). The exchange activity could not be quantified similarly, because the crude extract and early purification step fractions exhibited little or no exchange activity. Later purification fractions exhibited much more exchange activity, suggesting that an inhibitor was present in the impure fractions. The NiFeC EPR signal intensity was used as an indicator of the enzyme's capacity to catalyze exchange. This signal was extremely sensitive to oxygen; exposure to as little as 0.5 equiv/mol enzyme dimer resulted in substantial loss of intensity. The NiFeC intensities at each step in the purification were virtually invariant, indicating that the enzyme had not been exposed to oxygen and had not been inactivated towards catalyzing exchange. The ability to purify carbon monoxide dehydrogenase (CODH) without inactivating nearly any of the molecules suggests that it is quite stable under anaerobic conditions. The purified enzyme, which could not have lost functional metal ions during purification, contained 1.9 Ni and 11.3 Fe, similar to previous reports. The NiFeC EPR signal intensity from each purification fraction (0.2 spins/mol enzyme dimer) was as low as from previous preparations, indicating that its low spin quantitation is not the result of damage incurred during purification. If the low intensity arises from heterogeneity as proposed earlier, the heterogeneity must originate prior to purification.
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Affiliation(s)
- W Shin
- Department of Chemistry, Texas A&M University, College Station 77843
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