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Baik SM, Cynn HS, Shim JH, Lee JH, Shin AR, Lee KE. Effects of Log-Rolling Position on Hip-Abductor Muscle Activation During Side-Lying Hip-Abduction Exercise in Participants With Gluteus Medius Weakness. J Athl Train 2021; 56:945-951. [PMID: 33150402 DOI: 10.4085/306-20] [Citation(s) in RCA: 2] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Weakness of the gluteus medius and gluteus maximus is associated with a variety of musculoskeletal disorders. However, activation of synergistic muscles that are not targeted should be considered when prescribing side-lying hip-abduction (SHA) exercises. Log-rolling positions may affect hip-abductor activity during SHA. OBJECTIVE To determine the effects of log-rolling positions on gluteus medius, gluteus maximus, and tensor fasciae latae activity during SHA in participants with gluteus medius weakness. DESIGN Controlled laboratory study. SETTING University research laboratory. PATIENTS OR OTHER PARTICIPANTS Twenty-one participants with gluteus medius weakness. INTERVENTION(S) Three types of SHA were performed: frontal-plane SHA in neutral position (SHA-neutral), frontal-plane SHA in anterior log-rolling position (SHA-anterior rolling), and frontal-plane SHA in posterior log-rolling position (SHA-posterior rolling). MAIN OUTCOME MEASURE(S) Surface electromyography was used to measure hip-abductor activity. One-way repeated-measures analysis of variance was calculated to assess the statistical significance of the muscle activity. RESULTS The SHA-anterior rolling showed greater gluteus medius and gluteus maximus activation than the SHA-neutral (P = .003 and P < .001, respectively) and SHA-posterior rolling (P < .001 and P < .001, respectively). The SHA-neutral demonstrated greater gluteus medius and gluteus maximus activation than the SHA-posterior rolling (P < .001 and P = .001, respectively). The SHA-anterior rolling produced less tensor fasciae latae activation than the SHA-neutral (P < .001) and SHA-posterior rolling (P < .001). The SHA-neutral showed less tensor fasciae latae activation than the SHA-posterior rolling (P < .001). CONCLUSIONS The SHA-anterior rolling may be an effective exercise for increasing activation of the gluteus medius and gluteus maximus while decreasing activation of the tensor fasciae latae in participants with gluteus medius weakness.
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Affiliation(s)
- Seung-Min Baik
- Applied Kinesiology and Ergonomic Technology Laboratory, Department of Physical Therapy, The Graduate School, Yonsei University, Wonju-si, Republic of Korea.,Department of Physical Therapy, Baekseok University, Cheonan, Republic of Korea
| | - Heon-Seock Cynn
- Applied Kinesiology and Ergonomic Technology Laboratory, Department of Physical Therapy, The Graduate School, Yonsei University, Wonju-si, Republic of Korea
| | - Jae-Hun Shim
- Department of Physical Therapy, Baekseok University, Cheonan, Republic of Korea
| | - Ji-Hyun Lee
- Department of Physical Therapy, Baekseok University, Cheonan, Republic of Korea
| | - A-Reum Shin
- Applied Kinesiology and Ergonomic Technology Laboratory, Department of Physical Therapy, The Graduate School, Yonsei University, Wonju-si, Republic of Korea
| | - Kyung-Eun Lee
- Department of Physical Therapy, The Graduate School, Yonsei University, Wonju-si, Republic of Korea
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Kim H, Shim JH, Kim S, Park JH, Kim K, Min BI. Unusual Pressure-Induced Quantum Phase Transition from Superconducting to Charge-Density Wave State in Rare-Earth-Based Heusler LuPd_{2}In Compound. Phys Rev Lett 2020; 125:157001. [PMID: 33095605 DOI: 10.1103/physrevlett.125.157001] [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] [Received: 07/29/2019] [Revised: 03/10/2020] [Accepted: 09/10/2020] [Indexed: 06/11/2023]
Abstract
We investigate the pressure effects on the electronic structures and phonon properties of rare-earth-based cubic-Heusler compound LuPd_{2}In, on the basis of ab initio density functional theory. We find the occurrence of intriguing phase transition from the superconducting (SC) to charge-density wave (CDW) state under pressure (P), which is quite unusual in that the pressure is detrimental to the CDW state in usual systems. The SC transition temperature T_{C} of LuPd_{2}In increases first with increasing pressure, up to P_{C}≈28 GPa, above which a quantum phase transition into the CDW state takes place. This extraordinary transition originates from the occurrence of phonon softening instability at a special q=M in the Brillouin zone. We thus propose that LuPd_{2}In is a quite unique material, in which the CDW quantum critical point is realized under the SC dome by applying the pressure.
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Affiliation(s)
- Heejung Kim
- Department of Physics, POSTECH, Pohang 37673, Korea
- MPPHC-CPM, Max Planck POSTECH/Korea Research Initiative, Pohang 37673, Korea
| | - J H Shim
- Department of Physics, POSTECH, Pohang 37673, Korea
- Department of Chemistry, POSTECH, Pohang 37673, Korea
| | - Sooran Kim
- Department of Physics Education, Kyungpook National University, Daegu 41566, Korea
| | - Jae-Hoon Park
- Department of Physics, POSTECH, Pohang 37673, Korea
- MPPHC-CPM, Max Planck POSTECH/Korea Research Initiative, Pohang 37673, Korea
- Division of Advanced Materials Science, POSTECH, Pohang 37673, Korea
| | - Kyoo Kim
- Department of Physics, POSTECH, Pohang 37673, Korea
- MPPHC-CPM, Max Planck POSTECH/Korea Research Initiative, Pohang 37673, Korea
- Korea Atomic Energy Research Institute (KAERI), 111 Daedeok-daero, Daejeon 34057, Korea
| | - B I Min
- Department of Physics, POSTECH, Pohang 37673, Korea
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Park D, Cynn HS, Yi C, Choi WJ, Shim JH, Oh DW. Four-week training involving self-ankle mobilization with movement versus calf muscle stretching in patients with chronic stroke: a randomized controlled study. Top Stroke Rehabil 2019; 27:296-304. [PMID: 31742488 DOI: 10.1080/10749357.2019.1690831] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Background: In self-ankle mobilization with movement (S-MWM) therapy, a strap can be utilized to stabilize the posterior glide of the talus during ankle dorsiflexion movements.Objectives: Our objective was to compare the effects of 4-week self-mobilization with movement (S-MWM) with those of calf muscle stretching (CMS) on ankle dorsiflexion passive range of motion (DF-PROM), gait parameters, and fall risk in patients with chronic stroke with limited ankle dorsiflexion.Methods: Participants were randomized into the S-MWM (n = 19) and CMS groups (n = 19). Both groups received conventional physiotherapy for 30 minutes per session. In addition, S-MWM and CMS techniques were performed 3 times per week for 4 weeks and were performed by the participants themselves. Ankle DF-PROM, gait parameters, and fall risk were measured after 4 weeks of training.Results: After 4 weeks of training, both groups showed significant improvement in all outcome measures (p < .05). Furthermore, ankle DF-PROM, gait parameters (gait speed, cadence, and stride lengths on both sides), and fall risk showed greater improvement in the S-MWM group than in the CMS group (p < .05).Conclusions: This study shows that S-MWM training combined with conventional physiotherapy improved ankle DF-PROM, gait parameters, and fall risk in patients with chronic stroke.
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Affiliation(s)
- Donghwan Park
- Department of Physical Therapy, Graduate School, Yonsei University, Wonju, Kangwon-do, Republic of South Korea
| | - Heon-Seock Cynn
- Department of Physical Therapy, Graduate School, Yonsei University, Wonju, Kangwon-do, Republic of South Korea
| | - Chunghwi Yi
- Department of Physical Therapy, Graduate School, Yonsei University, Wonju, Kangwon-do, Republic of South Korea
| | - Woochol Joseph Choi
- Department of Physical Therapy, Graduate School, Yonsei University, Wonju, Kangwon-do, Republic of South Korea
| | - Jae-Hun Shim
- Department of Physical Therapy, Division of Health Science, Baekseok University, Cheonan-si, Chungcheongnam-do, Republic of South Korea
| | - Duck-Won Oh
- Department of Physical Therapy, College of Health and Medical Science, Cheongju University, Cheongju-si, Chungcheongbuk-do, Republic of South Korea
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Kim S, Yi S, Oh M, Jang BG, Nam W, Yoo YC, Lee M, Jeon H, Zoh I, Lee H, Zhang C, Kim KH, Seo J, Shim JH, Chae J, Kuk Y. Surface reconstruction and charge modulation in BaFe 2As 2 superconducting film. J Phys Condens Matter 2018; 30:315001. [PMID: 29916822 DOI: 10.1088/1361-648x/aacd85] [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: 06/08/2023]
Abstract
Whether or not epitaxially grown superconducting films have the same bulk-like superconducting properties is an important concern. We report the structure and the electronic properties of epitaxially grown Ba(Fe1-x Co x )2As2 films using scanning tunneling microscopy and scanning tunneling spectroscopy (STS). This film showed a different surface structure, [Formula: see text]R45° reconstruction, from those of as-cleaved surfaces from bulk crystals. The electronic structure of the grown film is different from that in bulk, and it is notable that the film exhibits the same superconducting transport properties. We found that the superconducting gap at the surface is screened at the Ba layer surface in STS measurements, and the charge density wave was observed at the surface in sample in the superconducting state.
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Affiliation(s)
- S Kim
- Department of Physics and Astronomy, Seoul National University, Seoul 08826, Republic of Korea
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Oikonomidou PR, Casu C, Yang Z, Crielaard B, Shim JH, Rivella S, Vogiatzi MG. Polycythemia is associated with bone loss and reduced osteoblast activity in mice. Osteoporos Int 2016; 27:1559-1568. [PMID: 26650379 PMCID: PMC5319412 DOI: 10.1007/s00198-015-3412-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [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: 09/22/2015] [Accepted: 11/05/2015] [Indexed: 01/19/2023]
Abstract
UNLABELLED Increased fragility has been described in humans with polycythemia vera (PV). Herein, we describe an osteoporotic phenotype associated with decreased osteoblast activity in a mouse model of PV and another mouse of polycythemia and elevated circulating erythropoietin (EPO). Our results are important for patients with PV or those treated with recombinant EPO (rEPO). INTRODUCTION PV and other myeloproliferative syndromes have been recently associated with an increased risk for fractures. However, the presence of osteoporosis in these patients has not been well documented. EPO, a hormone primarily known to stimulate erythropoiesis, has been shown recently to regulate bone homeostasis in mice. The aim of this study was to examine the bone phenotype of a mouse model of PV and compare it to that of animals with polycythemia caused by elevated circulating EPO. METHODS Bone mass and remodeling were evaluated by micro-computed tomography and histomorphometry. The JAK2(V617F) knock-in mouse, a model of human PV, manifests polycythemia and low circulating EPO levels. Results from this mouse were compared to wild type (wt) controls and the tg6 transgenic mouse that shows polycythemia caused by increased constitutive expression of EPO. RESULTS Compared to wt, both JAK2(V617F) and tg6 mice had a decrease in trabecular bone mass. Tg6 mice showed an additional modest decrease in cortical thickness and cortical bone volume per tissue volume (P < 0.01) suggesting a more severe bone phenotype than JAK2(V617F). Decreased osteoblast numbers and bone formation along with normal osteoclast numbers and activity were found in both mice. CONCLUSIONS This study indicates that PV is associated with low bone mass and decreased osteoblast activity in mice. Our results support future studies of osteoporosis in affected humans. Polycythemia caused by chronically elevated circulating EPO also results in bone loss, and implications on patients treated with rEPO should be evaluated.
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Affiliation(s)
- P R Oikonomidou
- Division of Pediatric Endocrinology, Weill Cornell Medical College, New York, NY, USA.
- Division of Hematology, Children's Hospital of Philadelphia, Abramson Research Center, 3615 Civic Center Blvd., Room 309 F, Philadelphia, PA, 19104, USA.
| | - C Casu
- Division of Pediatric Hematology/Oncology, Weill Cornell Medical College, New York, NY, USA
- Division of Hematology, Children's Hospital of Philadelphia, Abramson Research Center, 3615 Civic Center Blvd., Room 309 F, Philadelphia, PA, 19104, USA
| | - Z Yang
- Department of Medicine, Cancer Center, Weill Cornell Medical College, Belfer Research Building, 413 East 69th Street, 13th Floor, New York, NY,, 10021, USA
| | - B Crielaard
- Division of Pediatric Hematology/Oncology, Weill Cornell Medical College, New York, NY, USA
- Department of Polymer Chemistry and Bioengineering, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, Netherlands
| | - J H Shim
- Department of Pathology and Laboratory medicine, Weill Cornell Medical College, 1300 York Avenue, E-904, New York, NY,, 10065, USA
| | - S Rivella
- Division of Pediatric Hematology/Oncology, Weill Cornell Medical College, New York, NY, USA
- Division of Hematology, Children's Hospital of Philadelphia, Abramson Research Center, 3615 Civic Center Blvd., Room 316 B, Philadelphia, PA, 19104, USA
| | - M G Vogiatzi
- Division of Pediatric Endocrinology, Weill Cornell Medical College, New York, NY, USA
- Division of Endocrinology, Children's Hospital of Philadelphia, 3401 Civic Center Bvld., Philadelphia, PA, 19104, USA
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Kang CJ, Denlinger JD, Allen JW, Min CH, Reinert F, Kang BY, Cho BK, Kang JS, Shim JH, Min BI. Electronic Structure of YbB_{6}: Is it a Topological Insulator or Not? Phys Rev Lett 2016; 116:116401. [PMID: 27035312 DOI: 10.1103/physrevlett.116.116401] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Indexed: 06/05/2023]
Abstract
To finally resolve the controversial issue of whether or not the electronic structure of YbB_{6} is nontrivially topological, we have made a combined study using angle-resolved photoemission spectroscopy (ARPES) of the nonpolar (110) surface and density functional theory (DFT). The flat-band conditions of the (110) ARPES avoid the strong band bending effects of the polar (001) surface and definitively show that YbB_{6} has a topologically trivial B 2p-Yb 5d semiconductor band gap of ∼0.3 eV. Accurate determination of the low energy band topology in DFT requires the use of a modified Becke-Johnson exchange potential incorporating spin-orbit coupling and an on-site Yb 4f Coulomb interaction U as large as 7 eV. The DFT result, confirmed by a more precise GW band calculation, is similar to that of a small gap non-Kondo nontopological semiconductor. Additionally, the pressure-dependent electronic structure of YbB_{6} is investigated theoretically and found to transform into a p-d overlap semimetal with small Yb mixed valency.
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Affiliation(s)
- Chang-Jong Kang
- Department of Physics, PCTP, Pohang University of Science and Technology, (POSTECH) Pohang 37673, Korea
| | - J D Denlinger
- Advanced Light Source, Lawrence Berkeley Laboratory, Berkeley, California 94720, USA
| | - J W Allen
- Department of Physics, Randall Laboratory, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Chul-Hee Min
- Universität Würzburg, Experimentelle Physik VII, 97074 Würzburg, Germany
| | - F Reinert
- Universität Würzburg, Experimentelle Physik VII, 97074 Würzburg, Germany
| | - B Y Kang
- School of Materials Science and Engineering, GIST, Gwangju 61005, Korea
| | - B K Cho
- School of Materials Science and Engineering, GIST, Gwangju 61005, Korea
| | - J-S Kang
- Department of Physics, The Catholic University of Korea, Bucheon 14662, Korea
| | - J H Shim
- Department of Physics, PCTP, Pohang University of Science and Technology, (POSTECH) Pohang 37673, Korea
- Department of Chemistry and Division of Advanced Nuclear Engineering, POSTECH, Pohang 37673, Korea
| | - B I Min
- Department of Physics, PCTP, Pohang University of Science and Technology, (POSTECH) Pohang 37673, Korea
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Kim GA, Shim JH, Kim MJ, Kim SY, Won HJ, Shin YM, Kim PN, Kim KH, Lee SG, Lee HC. Radiofrequency ablation as an alternative to hepatic resection for single small hepatocellular carcinomas. Br J Surg 2015; 103:126-35. [DOI: 10.1002/bjs.9960] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 08/06/2015] [Accepted: 09/04/2015] [Indexed: 12/21/2022]
Abstract
Abstract
Background
This study aimed to investigate whether radiofrequency ablation (RFA) is an alternative to surgical resection for hepatocellular carcinoma (HCC) within the context of current guidelines.
Methods
This retrospective study included patients with normal portal pressure and serum bilirubin level who initially underwent liver resection or RFA for a single HCC of maximum size 3 cm. Between-group differences in cumulative rates of survival and recurrence specific for HCC were analysed in the entire cohort and in a propensity score-matched cohort.
Results
A total of 604 patients were enrolled, 273 in the liver resection group and 331 in the RFA group. The 5- and 10-year HCC-specific survival rates for the resection and RFA groups were 87·6 versus 82·1 per cent and 59·0 versus 61·2 per cent respectively (P = 0·214), whereas overall 5- and 10-year recurrence-free survival rates for the corresponding groups were 60·6 versus 39·4 per cent and 37·5 versus 25·1 per cent respectively (P < 0·001). In the propensity score-matched cohort (152 pairs), there were no differences in HCC-specific survival (hazard ratio (HR) 1·03 for RFAversus resection; P = 0·899), whereas recurrence-free survival again differed between the treatment groups (HR 1·75; P < 0·001). RFA was independently associated with poorer outcomes in terms of treatment-site recurrence-free survival (adjusted HR 1·66; P = 0·026), but not non-treatment-site recurrence-free survival (adjusted HR 1·15; P = 0·354).
Conclusion
Although RFA carries a higher risk of treatment-site recurrence than hepatic resection, it provides comparable overall survival in patients with a single small HCC without portal hypertension or a raised bilirubin level.
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Affiliation(s)
- G-A Kim
- Department of Gastroenterology, Asan Liver Centre, Seoul, Korea
- Health Screening and Promotion Centre, Seoul, Korea
| | - J H Shim
- Department of Gastroenterology, Asan Liver Centre, Seoul, Korea
| | - M-J Kim
- Department of Clinical Epidemiology and Biostatistics, Asan Medical Centre, University of Ulsan College of Medicine, Seoul, Korea
| | - S Y Kim
- Department of Radiology, Asan Liver Centre, Seoul, Korea
| | - H J Won
- Department of Radiology, Asan Liver Centre, Seoul, Korea
| | - Y M Shin
- Department of Radiology, Asan Liver Centre, Seoul, Korea
| | - P N Kim
- Department of Radiology, Asan Liver Centre, Seoul, Korea
| | - K-H Kim
- Department of Surgery, Asan Liver Centre, Seoul, Korea
| | - S-G Lee
- Department of Surgery, Asan Liver Centre, Seoul, Korea
| | - H C Lee
- Department of Gastroenterology, Asan Liver Centre, Seoul, Korea
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Jeon JS, Kim BH, Lee SH, Kwon HJ, Bae HJ, Kim SK, Park JA, Shim JH, Abd El-Aty AM, Shin HC. Simultaneous determination of arbutin and its decomposed product hydroquinone in whitening creams using high-performance liquid chromatography with photodiode array detection: Effect of temperature and pH on decomposition. Int J Cosmet Sci 2015; 37:567-73. [PMID: 25857400 DOI: 10.1111/ics.12228] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [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: 03/02/2015] [Accepted: 03/31/2015] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Arbutin is an effective agent for the treatment of melanin disorders. Arbutin may be converted to hydroquinone under conditions of high temperature, ultraviolet (UV) radiation and dilute acid. The aim of the current study was to develop an analytical method to determine the levels of arbutin and hydroquinone in whitening cosmetic products using high-performance liquid chromatography with photodiode array detection (HPLC-DAD). In addition, we investigated the effects of high temperature and pH on the decomposition of arbutin. METHODS Samples extracted using two-step sonications were separated on a C18 column using a gradient mobile phase consisting of water and methanol. A 60-mm (40 μL) DAD cell was used to enhance the sensitivity of hydroquinone determination. Thermal decomposition of arbutin was evaluated at temperatures ranging from 60 to 120°C for 1-36 h. RESULTS The method showed good linearity (R(2) ≥ 0.9997), precision (relative standard deviation, RSD < 5%) and acceptable extraction recovery (90-102.6%). The limits of quantitation for arbutin and hydroquinone were 0.0085 and 0.0119 μg mL(-1) , respectively. One sample of 21 cosmetic products tested contained arbutin at a concentration 1.61 g 100 g(-1) cream and 0.12 g 100 g(-1) cream of hydroquinone. Arbutin (327.18 ppm) decomposed after 6 h at 120°C and produced 10.73 ppm of hydroquinone. CONCLUSION The developed method is simple to detect both arbutin and hydroquinone simultaneously in cosmetic products, at an adequate level of sensitivity. Notably, temperature and pH did not influence the decomposition of arbutin to hydroquinone in a 2% arbutin cream.
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Affiliation(s)
- J S Jeon
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Konkuk University, Nuengdong-ro, Gwangjin-gu, Seoul, 143-701, Korea.,Public Health Research Division, Gyeonggi Province Institute of Health and Environment, 95, Pajang cheon-ro, Jangan-gu, Suwonsi, Gyeonggi Province, 440-290, Korea
| | - B H Kim
- Public Health Research Division, Gyeonggi Province Institute of Health and Environment, 95, Pajang cheon-ro, Jangan-gu, Suwonsi, Gyeonggi Province, 440-290, Korea
| | - S H Lee
- Public Health Research Division, Gyeonggi Province Institute of Health and Environment, 95, Pajang cheon-ro, Jangan-gu, Suwonsi, Gyeonggi Province, 440-290, Korea
| | - H J Kwon
- Public Health Research Division, Gyeonggi Province Institute of Health and Environment, 95, Pajang cheon-ro, Jangan-gu, Suwonsi, Gyeonggi Province, 440-290, Korea
| | - H J Bae
- Public Health Research Division, Gyeonggi Province Institute of Health and Environment, 95, Pajang cheon-ro, Jangan-gu, Suwonsi, Gyeonggi Province, 440-290, Korea
| | - S K Kim
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Konkuk University, Nuengdong-ro, Gwangjin-gu, Seoul, 143-701, Korea
| | - J A Park
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Konkuk University, Nuengdong-ro, Gwangjin-gu, Seoul, 143-701, Korea
| | - J H Shim
- Biotechnology Research Institute, College of Agriculture and Life Sciences, Chonnam National University, 300 Yongbong-dong, Buk-gu, Gwangju, 500-757, Korea
| | - A M Abd El-Aty
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Konkuk University, Nuengdong-ro, Gwangjin-gu, Seoul, 143-701, Korea.,Department of Pharmacology, Faculty of Veterinary Medicine, Cairo University, Giza, 12211, Egypt
| | - H C Shin
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Konkuk University, Nuengdong-ro, Gwangjin-gu, Seoul, 143-701, Korea
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Park EJ, Lee GH, Shim JH, Cho MH, Lee BS, Kim YB, Kim JH, Kim Y, Kim DW. Comparison of the toxicity of aluminum oxide nanorods with different aspect ratio. Arch Toxicol 2014; 89:1771-82. [PMID: 25155191 DOI: 10.1007/s00204-014-1332-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [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: 07/02/2014] [Accepted: 08/12/2014] [Indexed: 11/30/2022]
Abstract
Aluminum oxide nanoparticles are listed among 14 high-priority nanomaterials published by the Organization for Economic Co-operation and Development, but limited information is available on their potential hazards. In this study, we compared the toxicity of two different aluminum oxide nanorods (AlNRs) commercially available in vivo and in vitro. Considering aspect ratio, one was 6.2 ± 0.6 (long-AlNRs) and the other was 2.1 ± 0.4 (short-AlNRs). In mice, long-AlNRs induced longer and stronger inflammatory responses than short-AlNRs, and the degree reached the maximum on day 7 for both types and decreased with time. In addition, in vitro tests were performed on six cell lines derived from potential target organs for AlNPs, HEK-293 (kidney), HACAT (skin), Chang (liver), BEAS-2B (lung), T98G (brain), and H9C2 (heart), using MTT assay, ATP assay, LDH release, and xCELLigence system. Long-AlNRs generally produced stronger toxicity than short-AlNRs, and HEK-293 cells were the most sensitive for both AlNRs, followed by BEAS-2B cells, although results from 4 kinds of toxicity tests conflicted among the cell lines. Based on these results, we suggest that toxicity of AlNRs may be related to aspect ratio (and resultant surface area). Furthermore, novel in vitro toxicity testing methods are needed to resolve questionable results caused by the unique properties of nanoparticles.
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Affiliation(s)
- Eun-Jung Park
- Department of Molecular Science and Technology, Ajou University, Suwon, 443-749, Korea.
| | - Gwang-Hee Lee
- School of Civil, Environmental and Architectural Engineering, Korea University, Seoul, 136-713, Korea
| | - Jae-Hun Shim
- Department of Chemical Engineering, Kwangwoon University, Seoul, 139-701, Korea
| | - Myung-Haing Cho
- College of Veterinary Medicine, Seoul National University, Seoul, 151-742, Korea
| | - Byoung-Seok Lee
- Toxicologic Pathology Center, Korea Institute of Toxicology, Daejeon, Korea
| | - Yong-Bum Kim
- Toxicologic Pathology Center, Korea Institute of Toxicology, Daejeon, Korea
| | - Jae-Ho Kim
- Department of Molecular Science and Technology, Ajou University, Suwon, 443-749, Korea
| | - Younghun Kim
- Department of Chemical Engineering, Kwangwoon University, Seoul, 139-701, Korea
| | - Dong-Wan Kim
- School of Civil, Environmental and Architectural Engineering, Korea University, Seoul, 136-713, Korea.
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Zhao LB, Shi HB, Park S, Lee DG, Shim JH, Lee DH, Suh DC. Acute bleeding in the head and neck: angiographic findings and endovascular management. AJNR Am J Neuroradiol 2013; 35:360-6. [PMID: 24136646 DOI: 10.3174/ajnr.a3761] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND AND PURPOSE Life-threatening bleeding in the head and neck requires urgent management. This study evaluated the angiographic findings related to head and neck bleeding and presents endovascular management techniques. MATERIAL AND METHODS Sixty-one consecutive patients who presented with acute bleeding in the head and neck areas and subsequently underwent endovascular therapy between January 2002 and October 2012 were included in our study. We evaluated the angiographic findings, techniques, and results of endovascular management. RESULTS Contrast leakage (n = 10), pseudoaneurysm (n = 20), or both (n = 10) were the most common life-threatening angiographic findings (66%) and were the foci of immediate embolization or endoluminal vessel reconstruction. Seventeen patients (28%) had hypervascular staining of the tumor or mucosa, and 4 patients (6%) did not have any abnormal findings. The acute bleeding was successfully controlled by endovascular management according to the bleeding foci. Carotid arterial lesions, so-called "carotid blowout," required reconstructive or deconstructive therapy. Bleeding of the external carotid artery required specific branch embolization by a combination of various embolic materials. No procedure-related complications occurred except in 1 patient who experienced acute infarction caused by thromboemboli from the covered stent. Seventeen patients (28%) were retreated due to rebleeding after the mean 20-month follow-up. CONCLUSIONS Contrast leakage or a pseudoaneurysm or both seen on angiography are active bleeding foci and targets for therapy in patients with acute bleeding in the head and neck area. Despite different bleeding-control strategies according to vessel involvement, endovascular treatment is safe and effective for controlling hemorrhage.
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Affiliation(s)
- L-B Zhao
- From the Departments of Radiology and Research Institute of Radiology (L.-B.Z., H.B.S., S.P., D.-g.L., J.H.S., D.H.L., D.C.S.), University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Korea
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11
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Kwak JH, Zhao L, Kim JK, Park S, Lee DG, Shim JH, Lee DH, Kim JS, Suh DC. The outcome and efficacy of recanalization in patients with acute internal carotid artery occlusion. AJNR Am J Neuroradiol 2013; 35:747-53. [PMID: 24091441 DOI: 10.3174/ajnr.a3747] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND AND PURPOSE Acute occlusion of the ICA is often associated with poor outcomes and severe neurologic deficits. This study was conducted to evaluate outcome of the occluded ICA and efficacy of recanalization under protective flow arrest. MATERIALS AND METHODS Fifty consecutive patients who underwent endovascular treatment for acute ICA occlusion were identified from the prospectively collected data base. We assessed NIHSSo, occlusion type (cardioembolism vs atherosclerosis), occlusion level (supraclinoid-terminal, petrocavernous, or bulb-cervical), recanalization degree (TICI), and efficacy of recanalization (protective flow arrest vs nonprotection) leading to better outcome. RESULTS Successful recanalization (TICI ≥ 2) was obtained in 90% of patients and good recovery (mRS ≤ 2) in 60% of patients. Good outcome was related to National Institutes of Health Stroke Scale score on admission (P < .001), TICI (P < .007), occlusion type (P = .022), and occlusion level (P = .038). Poor initial patient status, less recanalization, cardioembolism, and supraclinoid-terminal occlusion were associated with poor prognosis. Application of protective flow arrest led to better outcome in the distal ICA segment than in the bulb-cervical segment. CONCLUSIONS In addition to the initial patient status and successful recanalization, the occlusion level or type of the occluded ICA could affect clinical outcome. In this study, treatment benefits of protective flow arrest were accentuated in patients with ICA occlusion above the bulb-cervical segment.
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Affiliation(s)
- J H Kwak
- From the Department of Radiology and Research Institute of Radiology (J.H.K., L.Z., S.P., D.-g.L., J.H.S., D.H.L., D.C.S.)
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12
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Abstract
We retrospectively studied the radiological and clinical results of a simple hemiresection arthroplasty, a modification of previous oblique distal ulnar resections, in 62 patients with rheumatoid arthritis (68 wrists) over a mean follow-up of 103 (range 60-173) months. Fourteen wrists (20%) became fused at the radiocarpal joint and 28 wrists fused (41%) at the midcarpal joints during follow-up. Severe ulnar translocation of the carpus was observed in two wrists (3%), radio-ulnar convergence in five wrists (7%), as well as a significant decrease of carpal height ratio, without any radiological findings of stylocarpal impingement. Improvements in forearm pronation and supination, and reduction in pain were maintained at the last follow-up. Grip strength was not significantly improved. The Jebsen-Taylor hand function test showed improvements in writing, card turning, and simulated feeding. Fifty-two patients (58 wrists, 85%) were satisfied with the results at the last follow-up. Simple hemiresection arthroplasty showed good long-term results with few complications.
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Affiliation(s)
- C H Lee
- Department of Orthopaedic Surgery, Hanil General Hospital, Seoul, Korea
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13
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Lee NJ, Oh JH, Ban JO, Shim JH, Lee HP, Jung JK, Ahn BW, Yoon DY, Han SB, Ham YW, Hong JT. 4-O-methylhonokiol, a PPARγ agonist, inhibits prostate tumour growth: p21-mediated suppression of NF-κB activity. Br J Pharmacol 2013; 168:1133-45. [PMID: 23043610 DOI: 10.1111/j.1476-5381.2012.02235.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Revised: 08/22/2012] [Accepted: 09/05/2012] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND AND PURPOSE The effects of 4-O-methylhonokiol (MH), a constituent of Magnolia officinalis, were investigated on human prostate cancer cells and its mechanism of action elucidated. EXPERIMENTAL APPROACH The anti-cancer effects of MH were examined in prostate cancer and normal cells. The effects were validated in vivo using a mouse xenograft model. KEY RESULTS MH increased the expression of PPARγ in prostate PC-3 and LNCap cells. The pull-down assay and molecular docking study indicated that MH directly binds to PPARγ. MH also increased transcriptional activity of PPARγ but decreased NF-κB activity. MH inhibited the growth of human prostate cancer cells, an effect attenuated by the PPARγ antagonist GW9662. MH induced apoptotic cell death and this was related to G(0) -G(1) phase cell cycle arrest. MH increased the expression of the cell cycle regulator p21, and apoptotic proteins, whereas it decreased phosphorylation of Rb and anti-apoptotic proteins. Transfection of PC3 cells with p21 siRNA or a p21 mutant plasmid on the cyclin D1/ cycline-dependent kinase 4 binding site abolished the effects of MH on cell growth, cell viability and related protein expression. In the animal studies, MH inhibited tumour growth, NF-κB activity and expression of anti-apoptotic proteins, whereas it increased the transcriptional activity and expression of PPARγ, and the expression of apoptotic proteins and p21 in tumour tissues. CONCLUSIONS AND IMPLICATION MH inhibits growth of human prostate cancer cells through activation of PPARγ, suppression of NF-κB and arrest of the cell cycle. Thus, MH might be a useful tool for treatment of prostate cancer.
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Affiliation(s)
- N J Lee
- College of Pharmacy, Chungbuk National University, Chungbuk, South Korea
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14
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Park S, Lee DG, Shim JH, Lee DH, Suh DC. Recanalization of symptomatic vertebral ostial occlusion in patients with acute or subacute stroke. AJNR Am J Neuroradiol 2013; 35:367-72. [PMID: 23907242 DOI: 10.3174/ajnr.a3681] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [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
SUMMARY Vertebral artery recanalization in symptomatic stenosis/occlusion remains controversial, as no definite evidence exists regarding this topic. There are only a few reports regarding the feasibility and safety of recanalization in the first segment of the vertebral artery with atherosclerotic vertebral ostial occlusion. We report our experience treating first segment occlusion in 8 patients and present a balloon protection technique used to reduce the thromboembolic burden during the stent placement procedure. The outcome at 3 months showed an mRS ≤2 except for a patient with a poor initial status with basilar artery occlusion. Revascularization of a rather long first segment occlusion is technically feasible and can be safely performed by use of embolic protection methods.
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Affiliation(s)
- S Park
- From the Department of Radiology and Research Institute of Radiology (S.P., D.-G.L., J.H.S., D.H.L., D.C.S.), University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Korea
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15
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Jeong DW, Choi HC, Kim CH, Chang SH, Sohn CH, Park HJ, Kang TD, Cho DY, Baek SH, Eom CB, Shim JH, Yu J, Kim KW, Moon SJ, Noh TW. Temperature evolution of itinerant ferromagnetism in SrRuO3 probed by optical spectroscopy. Phys Rev Lett 2013; 110:247202. [PMID: 25165956 DOI: 10.1103/physrevlett.110.247202] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Indexed: 06/03/2023]
Abstract
The temperature (T) dependence of the optical conductivity spectra σ(ω) of a single crystal SrRuO(3) thin film is studied over a T range from 5 to 450 K. We observed significant T dependence of the spectral weights of the charge transfer and interband d-d transitions across the ferromagnetic Curie temperature (T(c) ∼ 150 K). Such T dependence was attributed to the increase in the Ru spin moment, which is consistent with the results of density functional theory calculations. T scans of σ(Ω,T) at fixed frequencies Ω reveal a clear T(2) dependence below T(c), demonstrating that the Stoner mechanism is involved in the evolution of the electronic structure. In addition, σ(Ω,T) continues to evolve at temperatures above T(c), indicating that the local spin moment persists in the paramagnetic state. This suggests that SrRuO(3) is an intriguing oxide system with itinerant ferromagnetism.
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Affiliation(s)
- D W Jeong
- Center for Functional Interfaces of Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 151-747, Korea and Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea
| | - Hong Chul Choi
- Department of Chemistry, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Choong H Kim
- Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea
| | - Seo Hyoung Chang
- Center for Functional Interfaces of Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 151-747, Korea and Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea
| | - C H Sohn
- Center for Functional Interfaces of Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 151-747, Korea and Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea
| | - H J Park
- Center for Functional Interfaces of Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 151-747, Korea and Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea
| | - T D Kang
- Center for Functional Interfaces of Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 151-747, Korea and Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea
| | - Deok-Yong Cho
- Center for Functional Interfaces of Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 151-747, Korea and Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea
| | - S H Baek
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - C B Eom
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - J H Shim
- Department of Chemistry, Pohang University of Science and Technology, Pohang 790-784, Korea and Division of Advanced Nuclear Engineering, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - J Yu
- Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea
| | - K W Kim
- Department of Physics, Chungbuk National University, Cheongju 361-763, Korea
| | - S J Moon
- Department of Physics, Hanyang University, Seoul 133-791, Korea
| | - T W Noh
- Center for Functional Interfaces of Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 151-747, Korea and Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea
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16
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Neumann P, Jakobi I, Dolde F, Burk C, Reuter R, Waldherr G, Honert J, Wolf T, Brunner A, Shim JH. High-precision nanoscale temperature sensing using single defects in diamond. Nano Lett 2013; 13:2738-42. [PMID: 23721106 DOI: 10.1021/nl401216y] [Citation(s) in RCA: 216] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Measuring local temperature with a spatial resolution on the order of a few nanometers has a wide range of applications in the semiconductor industry and in material and life sciences. For example, probing temperature on the nanoscale with high precision can potentially be used to detect small, local temperature changes like those caused by chemical reactions or biochemical processes. However, precise nanoscale temperature measurements have not been realized so far owing to the lack of adequate probes. Here we experimentally demonstrate a novel nanoscale temperature sensing technique based on optically detected electron spin resonance in single atomic defects in diamonds. These diamond sensor sizes range from a micrometer down to a few tens of nanometers. We achieve a temperature noise floor of 5 mK/Hz(1/2) for single defects in bulk sensors. Using doped nanodiamonds as sensors the temperature noise floor is 130 mK/Hz(1/2) and accuracies down to 1 mK for nanocrystal sizes and therefore length scales of a few tens of nanometers. This combination of precision and position resolution, combined with the outstanding sensor photostability, should allow the measurement of the heat produced by chemical interactions involving a few or single molecules even in heterogeneous environments like cells.
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Affiliation(s)
- P Neumann
- 3rd Physikalisches Institut, Research Center Scope and IQST, University of Stuttgart, 70569 Stuttgart, Germany.
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17
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Shim JH, Bertaina S, Gambarelli S, Mitra T, Müller A, Baibekov EI, Malkin BZ, Tsukerblat B, Barbara B. Decoherence window and electron-nuclear cross relaxation in the molecular magnet V15. Phys Rev Lett 2012; 109:050401. [PMID: 23006148 DOI: 10.1103/physrevlett.109.050401] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Indexed: 06/01/2023]
Abstract
Rabi oscillations in the V(15) single molecule magnet embedded in the surfactant (CH(3))(2)[CH(3)(CH(2))(16)CH(2)](2)N(+) have been studied at different microwave powers. An intense damping peak is observed when the Rabi frequency Ω(R) falls in the vicinity of the Larmor frequency of protons ω(N). The experiments are interpreted by a model showing that the damping (or Rabi) time τ(R) is directly associated with decoherence caused by electron-nuclear cross relaxation in the rotating reference frame. This decoherence induces energy dissipation in the range ω(N) - σ(e) < Ω(R) < ω(N), where σ(e) is the mean superhyperfine field induced by protons at V(15). Weaker decoherence without dissipation takes place outside this window. Specific estimations suggest that this rapid cross relaxation in a resonant microwave field, observed for the first time in V(15), should also take place, e.g., in Fe(8) and Mn(12).
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Affiliation(s)
- J H Shim
- Laboratoire de Chimie Inorganique et Biologique, INAC, CEA, Grenoble, France
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18
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Choi HC, Min BI, Shim JH, Haule K, Kotliar G. Temperature-dependent Fermi surface evolution in heavy fermion CeIrIn5. Phys Rev Lett 2012; 108:016402. [PMID: 22304274 DOI: 10.1103/physrevlett.108.016402] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Indexed: 05/31/2023]
Abstract
We address theoretically the evolution of the heavy fermion Fermi surface (FS) as a function of temperature (T), using a first principles dynamical mean-field theory approach combined with density functional theory. We focus on the archetypical heavy electrons in CeIrIn{5}. Upon cooling, both the quantum oscillation frequencies and cyclotron masses show logarithmic scaling behavior [∼ln(T{0}/T)] with different characteristic temperatures T{0}=130 and 50 K, respectively. The enlargement of the electron FSs at low T is accompanied by topological changes around T=10-50 K. The resistivity coherence peak observed at T≃50 K is the result of the competition between the binding of incoherent 4f electrons to the spd conduction electrons at Fermi level (E{F}) and the formation of coherent 4f electrons.
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Affiliation(s)
- Hong Chul Choi
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
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19
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Park J, Lee G, Wolff-Fabris F, Koh YY, Eom MJ, Kim YK, Farhan MA, Jo YJ, Kim C, Shim JH, Kim JS. Anisotropic Dirac fermions in a Bi square net of SrMnBi2. Phys Rev Lett 2011; 107:126402. [PMID: 22026779 DOI: 10.1103/physrevlett.107.126402] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Indexed: 05/31/2023]
Abstract
We report the observation of highly anisotropic Dirac fermions in a Bi square net of SrMnBi(2), based on a first-principles calculation, angle-resolved photoemission spectroscopy, and quantum oscillations for high-quality single crystals. We found that the Dirac dispersion is generally induced in the (SrBi)(+) layer containing a double-sized Bi square net. In contrast to the commonly observed isotropic Dirac cone, the Dirac cone in SrMnBi(2) is highly anisotropic with a large momentum-dependent disparity of Fermi velocities of ~8. These findings demonstrate that a Bi square net, a common building block of various layered pnictides, provides a new platform that hosts highly anisotropic Dirac fermions.
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Affiliation(s)
- Joonbum Park
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
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20
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Shim JH, Oh DW. Case report: Physiotherapy strategies for a woman with symphysis pubis diastasis occurring during labour. Physiotherapy 2011; 98:89-91. [PMID: 22265390 DOI: 10.1016/j.physio.2011.01.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Accepted: 01/21/2011] [Indexed: 01/13/2023]
Abstract
This case report demonstrates a therapeutic exercise program as a noninvasive functional treatment for symphysis pubis diastasis (SPD) and reports its results. A 32-year-old primigravida with SPD during labour received a specific functional exercise program, which consisted of abdominal stabilization and strengthening of the pelvic floor muscles, hip adductors, and extensors; training for bed mobility; and walking training with suitable aids. The program was performed for 1-hour per session, twice a day, for 2 weeks. Before the intervention, the patient was totally dependent on others for performing her daily activities owing to severe pain in the pelvic region. After the 2-week intervention, however, the interpubic distance was reduced by 36% (from 22 mm to 14 mm), and pain and functional disability were remarkably improved. Moreover, the patient could walk independently for 30 m with a pelvic corset. Our results suggest that a systematically designed functional rehabilitation program may be beneficial in the functional recovery of patients suffering from SPD related to pregnancy.
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Affiliation(s)
- Jae-Hun Shim
- Department of Physical therapy, Division of Health Science, Baekseok University, Cheonan City, Republic of Korea
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21
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Cha TH, Oh DW, Shim JH. Noninvasive Treatment Strategy for Swallowing Problems Related to Prolonged Nonoral Feeding in Spinal Muscular Atrophy Type II. Dysphagia 2010; 25:261-4. [DOI: 10.1007/s00455-009-9269-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2009] [Accepted: 12/21/2009] [Indexed: 11/29/2022]
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22
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Bertaina S, Shim JH, Gambarelli S, Malkin BZ, Barbara B. Spin-orbit qubits of rare-earth-metal ions in axially symmetric crystal fields. Phys Rev Lett 2009; 103:226402. [PMID: 20366115 DOI: 10.1103/physrevlett.103.226402] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Indexed: 05/29/2023]
Abstract
Contrary to the well-known spin qubits, rare-earth-metal qubits are characterized by a strong influence of crystal field due to large spin-orbit coupling. At low temperature and in the presence of resonance microwaves, it is the magnetic moment of the crystal-field ground state which nutates (for several micros) and the Rabi frequency Omega(R) is anisotropic. Here, we present a study of the variations of Omega(R)(H(0)) with the magnitude and direction of the static magnetic field H(0) for the odd 167Er isotope in a single crystal CaWO(4):Er(3+). The hyperfine interactions split the Omega(R)(H(0)) curve into eight different curves which are fitted numerically and described analytically. These "spin-orbit qubits" should allow detailed studies of decoherence mechanisms which become relevant at high temperature and open new ways for qubit addressing using properly oriented magnetic fields.
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Affiliation(s)
- S Bertaina
- IM2NP, CNRS and Université Paul Cézanne, Avenue Escadrille Normandie Niemen-Case 142-13397 Marseille Cedex 20, France
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23
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Yu JS, Shim JH, Chung JJ, Kim JH, Kim KW. Double contrast-enhanced MRI of viral hepatitis-induced cirrhosis: correlation of gross morphological signs with hepatic fibrosis. Br J Radiol 2009; 83:212-7. [PMID: 19505965 DOI: 10.1259/bjr/70974553] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The purpose of this study was to evaluate the diagnostic ability of the expanded gallbladder fossa and right posterior hepatic notch signs for hepatic fibrosis determined by double contrast-enhanced MRI. For patients with chronic viral hepatitis B (n = 96) or hepatitis C (n = 13) who underwent gadopentate dimeglumine-enhanced dynamic MRI followed by ferucarbotran-enhanced gradient-echo imaging, the degree of parenchymal fibrosis was categorised into three groups based on the extent of reticulation and nodularity: (1) pre-cirrhotic or minimal fibrosis; (2) mild to moderate fibrosis; (3) advanced cirrhosis. Each group was evaluated for the presence of a sharp notch in the posterior-medial surface of the right lobe of the liver and expanded gallbladder fossa. The expanded gallbladder fossa sign gradually increased with an increasing degree of fibrosis (Group 1, 50%; Group 2, 61%; Group 3, 78%), and there was no significant difference (p>0.5) between hepatitis B (67%) and C (73%). In the case of the right posterior hepatic notch sign, only 6% of Group 1 and Group 2 patients were positive; 27% of hepatitis B patients and 90% of hepatitis C patients in Group 3 exhibited the sign (p<0.05). Owing to its low prevalence, even in advanced cirrhosis, the right posterior hepatic notch sign is of little value in the diagnosis of cirrhosis due to chronic hepatitis B virus infection, whereas an expanded gallbladder fossa could be used as a non-specific indicator of early fibrosis before the gross appearance of advanced hepatic fibrosis.
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Affiliation(s)
- J S Yu
- Department of Radiology and the Research Institute of Radiological Science, Yonsei University College of Medicine, Gangnam Severance Hospital, Seoul, Republic of Korea.
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24
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Park SY, Yoo SS, Shim JH, Chin KB. Physicochemical properties, and antioxidant and antimicrobial effects of garlic and onion powder in fresh pork belly and loin during refrigerated storage. J Food Sci 2009; 73:C577-84. [PMID: 19019099 DOI: 10.1111/j.1750-3841.2008.00896.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Pork loin and belly cuts were pumped to 110% of their original weight with solutions containing 5% of various ingredients (sodium ascorbate, garlic, and onion powder), and evaluated the physicochemical properties, and antioxidant and antimicrobial activities during refrigerated storage at 8 degrees C. The addition of garlic and onion powder tended to increase redness (a) and yellowness (b) in both the belly lean and loin with the exception of a few cases. Free fatty acid values in both pork belly and loin cuts were reduced with the addition of these ingredients, as compared to the control. Significant differences in peroxide values were observed in sodium ascorbate and garlic-injected belly, and in sodium ascorbate and onion-injected loin, as compared to the control. Thiobarbituric acid reactive substance values in the pork belly with garlic or onion powder were significantly lower than in the belly without these ingredients or with sodium ascorbate (P < 0.05). Total plate counts were lower in both the belly and loin containing garlic and onion powder, as compared to the control. In both the belly and loin cuts, the content of oxidative products (volatile compounds) was reduced with the addition of garlic and onion powder, particularly the aldehydes (hexanal). Overall, garlic and onion in enhanced meats showed an antioxidant activity as effective as that of sodium ascorbate and also an antimicrobial effect to inhibit the growth of total bacteria and Enterobacteriaceae.
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Affiliation(s)
- S Y Park
- Dept. of Culinary and Foodservice Management, Sejong Univ., Seoul, Korea 506-714
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Chae JI, Ju SK, Lee MK, Park JH, Yoon JH, Shim JH, Lee DS. [cDNA cloning and analysis of tissue-specific gene expression of rat urocortin II]. Mol Biol (Mosk) 2009; 43:91-96. [PMID: 19334530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The corticotropin-releasing hormone (CRH) family of neuropeptides includes CRH (a 41 amino acid hypothalamic peptide) and urocortin. Corticotropin-releasing factor (CRF), a peptide first isolated from mammalian, plays an important role in the regulation of the pituitary-adrenal axis, and in endocrine, autonomic, immune and behavioral responses to stress. In this study we cloned rat urocortin II (UCNII) cDNA from rat mid-brain by RT-PCR. The rat UCNII clone contained an open reading frame (ORF) coding 109 amino acids which shared 90% and 63% homology with mouse and human homologues, respectively, The expression of UCN HII mRNA is mainly distributed in bone marrow, ovary, uterus, hypophysis, adrenal gland, and skin. In this study, rat recombinant UCN was expressed in E. coli and purified in active form. Furthermore, purified recombinant UCN II protein specifically binds to CRF receptor 2 in rat ROS 17/2.8 and GH3 cells by flow-cytometry analysis. UCN II cDNA clone obtained in this study will be useful for further investigation on behavioral responses to stress in rats.
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Kim A, Kwon OS, Kim SO, He L, Bae EY, Lee MS, Jeong SJ, Shim JH, Yoon DY, Kim CH, Moon A, Kim KE, Ahn JS, Kim BY. Caspase-3 activation as a key factor for HBx-transformed cell death. Cell Prolif 2008; 41:755-74. [PMID: 18700866 DOI: 10.1111/j.1365-2184.2008.00550.x] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVES Nuclear factor-kappa B (NF-kappaB) activation has been associated with the tumorigenic growth of hepatitis B virus X protein (HBx)-transformed cells. This study was aimed to find a key target for treatment of HBx-mediated cancers. MATERIALS AND METHODS NF-kappaB activation, endoplasmic reticulum-stress (ER-stress), caspase-3 activation, and cell proliferation were evaluated after Chang/HBx cells permanently expressing HBx viral protein were treated with inhibitors of NF-kappaB, proteasome and DNA topoisomerase. RESULTS Inhibition of NF-kappaB transcriptional activity by transient transfection with mutant plasmids encoding Akt1 and glycogen synthase kinase-3beta (GSK-3beta), or by treatment with chemical inhibitors, wortmannin and LY294002, showed little effect on the survival of Chang/HBx cells. Furthermore, IkappaBalpha (S32/36A) mutant plasmid or other NF-kappaB inhibitors, 1-pyrrolidinecarbonidithioic acid and sulphasalazine, were also shown to have little effect on the cell proliferation. By contrast, proteasome inhibitor-1 (Pro1) and MG132 enhanced the HBx-induced ER-stress response and the subsequent activation of caspase-12, -9 and -3 and reduced cell proliferation. Camptothecin (CPT), however, triggered activation of caspase-3 without induction of caspase-12, and reduced cell proliferation. In addition, CPT-induced cell death was reversed by pre-treatment with z-DEVD, a caspase-3-specific inhibitor. CONCLUSIONS Detailed exploitation of the regulators of caspase-3 activation could open the gate for finding an efficient target for development of anticancer therapeutics against HBx-transformed hepatocellular carcinoma.
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Affiliation(s)
- A Kim
- Functional Metabolomics Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Yuseong, South Korea
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Khay S, Choi JH, Abd El-Aty AM, Mamun MIR, Park BJ, Goudah A, Shin HC, Shim JH. Dissipation behavior of lufenuron, benzoylphenylurea insecticide, in/on Chinese cabbage applied by foliar spraying under greenhouse conditions. Bull Environ Contam Toxicol 2008; 81:369-372. [PMID: 18592122 DOI: 10.1007/s00128-008-9490-x] [Citation(s) in RCA: 17] [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] [Subscribe] [Scholar Register] [Received: 01/14/2008] [Accepted: 06/06/2008] [Indexed: 05/26/2023]
Abstract
Chinese cabbage has long been consumed as a staple food by the Koreans in various forms of fresh, salted, or fermented as kimchi. To fulfill the off-season demand for this crop, it has become a common practice to be cultivated under greenhouse conditions. Since pesticide residues in/on leafy vegetables have strongly concerned with food safety in the Korean society, the changes of lufenuron residues, in/on Chinese cabbage applied by foliar spraying under greenhouse conditions was investigated. Lufenuron 5% emulsifiable concentrate (EC) was sprayed with diluted solution of recommended and double doses to the crop. The shoots of the cabbage were harvested immediately after spraying, and sequentially the harvests were conveyed to analyze the residual amounts. The deposited level of the analyte in/on Chinese cabbage under greenhouse conditions seemed to be difficult to produce the crop with 0.2 ppm of maximum residue limit (MRL) of the Korea Food and Drug Administration (KFDA).
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Affiliation(s)
- S Khay
- Natural Products Chemistry Laboratory, Institute of Agricultural Science and Technology, Chonnam National University, 300 Yong-Bong Dong, Buk-gu, Gwangju 500-757, Republic of Korea
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Shim JH, Haule K, Savrasov S, Kotliar G. Screening of magnetic moments in PuAm alloy: local density approximation and dynamical mean field theory study. Phys Rev Lett 2008; 101:126403. [PMID: 18851396 DOI: 10.1103/physrevlett.101.126403] [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: 05/25/2008] [Indexed: 05/26/2023]
Abstract
The puzzling absence of Pu magnetic moments in a PuAm environment is explored using the self-consistent dynamical mean field theory calculations in combination with the local density approximation. We argue that delta-Pu-Am alloys provide an ideal testbed for investigating the screening of moments from the single impurity limit to the dense limit. Several important effects can be studied: volume expansion, shift of the bare Pu on-site f energy level, and the reduction of the hybridization cloud resulting from the collective character of the Kondo effect in the Anderson lattice. These effects compensate each other and result in a coherence scale, which is independent of alloy composition, and is around 800 K.
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Affiliation(s)
- J H Shim
- Department of Physics, Rutgers University, Piscataway, NJ 08854, USA
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Chae JI, Ju SK, Lee MK, Park JH, Shim JH, Lee KK, Lee DS. [Cloning of rat TARC cDNA and analysis of tissue-specific mRNA expression]. Mol Biol (Mosk) 2008; 42:639-644. [PMID: 18856064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Thymus and activation-regulated chemokine (TARC) is one that selectively controls the migration of type 2-helper T lymphocytes into inflammatory lesions. TARC is a CC chemokine, and plays an essential role in recruiting CC chemokine receptor 4-positive Th2 cells to allergic lesions. We cloned TARC cDNA from rat thymus using RT-PCR. The rat TARC clone contained a full-length open reading frame encoding 93 amino acids that showed 83% and 66% homology with mouse and human homologs, respectively. The expression of TARC mRNA was mainly in the lymphoid organs, for example, the thymus, spleen, and lymph node. The recombinant TARC was expressed in Escherichia coli and purified in an active form. In addition, the purified rat TARC with S-tagged specifically binds to human CCR4 in CD4.CCR4-transfected HOS cells by Cell-binding assay using flow-cytometry. The TARC cDNA clones obtained in this study will be valuable for future studies on allergic diseases in rats.
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Shim JH, Raman KV, Park YJ, Santos TS, Miao GX, Satpati B, Moodera JS. Large spin diffusion length in an amorphous organic semiconductor. Phys Rev Lett 2008; 100:226603. [PMID: 18643439 DOI: 10.1103/physrevlett.100.226603] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2008] [Indexed: 05/26/2023]
Abstract
We directly measured a spin diffusion length (lambdas) of 13.3 nm in amorphous organic semiconductor (OS) rubrene (C42H28) by spin polarized tunneling. In comparison, no spin-conserved transport has been reported in amorphous Si or Ge. Absence of dangling bond defects can explain the spin transport behavior in amorphous OS. Furthermore, when rubrene barriers were grown on a seed layer, the elastic tunneling characteristics were greatly enhanced. Based on our findings, lambdas in single-crystalline rubrene can be expected to reach even millimeters, showing the potential for organic spintronics development.
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Affiliation(s)
- J H Shim
- Francis Bitter Magnet Laboratory, MIT, Cambridge, Massachusetts 02139, USA
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Abstract
We compute the electronic structure, momentum resolved spectral function and optical conductivity of the new superconductor LaO1-xFxFeAs within the combination of the density functional theory and dynamical mean field theory. We find that the compound in the normal state is a strongly correlated metal and the parent compound is a bad metal at the verge of the metal insulator transition. We argue that the superconductivity is not phonon mediated.
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Affiliation(s)
- K Haule
- Department of Physics, Rutgers University, Piscataway, New Jersey 08854, USA
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Abstract
We address the fundamental question of crossover from the localized to the itinerant state of a paradigmatic heavy fermion material: CeIrIn5. The temperature evolution of the one-electron spectra and the optical conductivity are predicted from first-principles calculation. The buildup of coherence in the form of a dispersive many-body feature is followed in detail, and its effects on the conduction electrons of the material are revealed. We find multiple hybridization gaps and link them to the crystal structure of the material. Our theoretical approach explains the multiple peak structures observed in optical experiments and the sensitivity of CeIrIn5 to substitutions of the transition metal element and may provide a microscopic basis for the more phenomenological descriptions currently used to interpret experiments in heavy fermion systems.
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Affiliation(s)
- J H Shim
- Center for Materials Theory, Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854, USA.
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Cho SK, Abd El-Aty AM, Choi JH, Kim MR, Shim JH. Optimized conditions for the extraction of secondary volatile metabolites in Angelica roots by accelerated solvent extraction. J Pharm Biomed Anal 2007; 44:1154-8. [PMID: 17446029 DOI: 10.1016/j.jpba.2007.03.011] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [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: 01/02/2007] [Revised: 02/26/2007] [Accepted: 03/13/2007] [Indexed: 10/23/2022]
Abstract
Accelerated solvent extraction (ASE) of three common Angelica species found in Asia: Angelica sinensis (Oliv.) Diels from China, Angelica acutiloba (Sieb. et Zucc.) Kitagawa from Japan, and Angelica gigas Nakai from Korea was investigated. Preliminary experiments, including the selection of the solvent, extraction time, pressure, static cycle and time were investigated to optimize experimental parameters. Kováts indices and mass spectra were used to identify the components in the various fractions. These were then confirmed using gas chromatography-mass spectrometry (GC-MS). A total of 18 compounds were identified, with qualitative differences and similarities observed among the cultivars. From the 18 compounds found in the ASE extract of danggui cultivars, the major components were decursin, decursinol angelate (A. gigas); butylidene dihydrophthalide, 4-hydroxy-4-methyl-2-pentanone (A. sinensis); and 9,12-octadecanoic acid in Angelica acutiloba. The optimum ASE operating conditions were n-hexane as extraction solvent, extraction temperature and pressure of 80 degrees C and 1500 atm, respectively, static cycle of 2 min, and static time of 10 min. Under these conditions, the percentages of main analytes were increased.
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Affiliation(s)
- S-K Cho
- Natural Products Chemistry Laboratory, Institute of Agricultural Science and Technology, College of Agriculture and Life Science, Chonnam National University, 300 Yong-Bong Dong, Buk-Ku, Gwangju 500-757, Republic of Korea
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Shim JH, Kim SE, Woo DH, Kim SK, Oh CH, McKay R, Kim JH. Directed differentiation of human embryonic stem cells towards a pancreatic cell fate. Diabetologia 2007; 50:1228-38. [PMID: 17457565 DOI: 10.1007/s00125-007-0634-z] [Citation(s) in RCA: 168] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2006] [Accepted: 01/15/2007] [Indexed: 12/13/2022]
Abstract
AIMS/HYPOTHESIS The relative lack of successful pancreatic differentiation of human embryonic stem cells (hESCs) may suggest that directed differentiation of hESCs into definitive endoderm and subsequent commitment towards a pancreatic fate are not readily achieved. The aim of this study was to investigate whether sequential exposure of hESCs to epigenetic signals that mimic in vivo pancreatic development can efficiently generate pancreatic endodermal cells, and whether these cells can be further matured and reverse hyperglycaemia upon transplantation. MATERIALS AND METHODS The hESCs were sequentially treated with serum, activin and retinoic acid (RA) during embryoid body formation. The patterns of gene expression and protein production associated with embryonic germ layers and pancreatic endoderm were analysed by RT-PCR and immunostaining. The developmental competence and function of hESC-derived PDX1-positive cells were evaluated after in vivo transplantation. RESULTS Sequential treatment with serum, activin and RA highly upregulated the expression of the genes encoding forkhead box protein A2 (FOXA2), SRY-box containing gene 17 (SOX17), pancreatic and duodenal homeobox 1 (PDX1) and homeobox HB9 (HLXB9). The population of pancreatic endodermal cells that produced PDX1 was significantly increased at the expense of ectodermal differentiation, and a subset of the PDX1-positive cells also produced FOXA2, caudal-type homeobox transcription factor 2 (CDX2), and nestin (NES). After transplantation, the PDX1-positive cells further differentiated into mature cell types producing insulin and glucagon, resulting in amelioration of hyperglycaemia and weight loss in streptozotocin-treated diabetic mice. CONCLUSIONS/INTERPRETATION Our strategy allows the progressive differentiation of hESCs into pancreatic endoderm capable of generating mature pancreatic cell types that function in vivo. These findings may establish the basis of further investigations for the purification of transplantable islet progenitors derived from hESCs.
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Affiliation(s)
- J H Shim
- Division of Biotechnology, College of Life Sciences and Biotechnology, Korea University, West Building/Room 304, Science Campus, 1 Anam-dong 5-ga, Sungbuk-goo, Seoul 136-713, Republic of Korea
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35
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Shim JH, Haule K, Kotliar G. Fluctuating valence in a correlated solid and the anomalous properties of δ-plutonium. Nature 2007; 446:513-6. [PMID: 17392780 DOI: 10.1038/nature05647] [Citation(s) in RCA: 221] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2006] [Accepted: 01/26/2007] [Indexed: 11/09/2022]
Abstract
Although the nuclear properties of the late actinides (plutonium, americium and curium) are fully understood and widely applied to energy generation, their solid-state properties do not fit within standard models and are the subject of active research. Plutonium displays phases with enormous volume differences, and both its Pauli-like magnetic susceptibility and resistivity are an order of magnitude larger than those of simple metals. Curium is also highly resistive, but its susceptibility is Curie-like at high temperatures and orders antiferromagnetically at low temperatures. The anomalous properties of the late actinides stem from the competition between itinerancy and localization of their f-shell electrons, which makes these elements strongly correlated materials. A central problem in this field is to understand the mechanism by which these conflicting tendencies are resolved in such materials. Here we identify the electronic mechanisms responsible for the anomalous behaviour of late actinides, revisiting the concept of valence using a theoretical approach that treats magnetism, Kondo screening, atomic multiplet effects and crystal field splitting on the same footing. We find that the ground state in plutonium is a quantum superposition of two distinct atomic valences, whereas curium settles into a magnetically ordered single valence state at low temperatures. The f(7) configuration of curium is contrasted with the multiple valences of the plutonium ground state, which we characterize by a valence histogram. The balance between the Kondo screening and magnetism is controlled by the competition between spin-orbit coupling, the strength of atomic multiplets and the degree of itinerancy. Our approach highlights the electronic origin of the bonding anomalies in plutonium, and can be applied to predict generalized valences and the presence or absence of magnetism in other compounds starting from first principles.
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Affiliation(s)
- J H Shim
- Department of Physics and Astronomy and Center for Condensed Matter Theory, Rutgers University, Piscataway, New Jersey 08854-8019, USA
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36
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Abd El-Aty AM, Goudah A, Mouneir SM, Sunwoo YE, Jang JH, Shin JG, Shim JH, Shimoda M. Acute-phase response alters the disposition kinetics of cefepime following intravenous administration to rabbits. Vet Res Commun 2006; 31:67-75. [PMID: 17186405 DOI: 10.1007/s11259-006-3405-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/07/2005] [Indexed: 11/24/2022]
Abstract
The effect of experimentally induced fever on the pharmacokinetics of cefepime administered intravenously at a dose of 75 mg/kg bw was studied in six healthy rabbits. The study was conducted in two consecutive phases, separated by a washout period of 2 weeks. Infection was induced by the intravenous inoculation of 5 x 10(8) cfu of Escherichia coli 24 h before the pharmacokinetic investigation was carried out. Serial blood samples for cefepime concentration determination were obtained for 48 h following drug administration. The concentrations of cefepime in the plasma were determined by a quantitative microbiological assay using an agar-gel diffusion method employing Bacillus subtilis ATCC 6633 as the test organism, with a level of detectability of approximately 0.10 microg/ml. Cefepime plasma concentrations versus time were evaluated by non-compartmental methods using WinNonLin. Cefepime was well tolerated and no serious adverse events were observed. Rectal temperature increased 1 degree C 24 h post injection in infected animals. Highly significant differences in the blood plasma concentrations of cefepime were observed between febrile and healthy animals at all the sampling times. This could explain the greater area under the plasma level-time curve of the drug in febrile compared with healthy animals. The results from pharmacokinetic calculations showed that both the distribution volume at steady state (V (dss)) and body clearance (CL(tot)) were affected in febrile as compared to healthy animals. The mean values of V (dss) and CL(tot) of cefepime in healthy rabbits were 1.168 L/kg and 0.303 L/kg/h, respectively. As compared with healthy animals, the mean estimates of V (dss) (0.917 L/kg) and CL(tot) (0.205 L/kg per h) of cefepime were significantly lower, whereas t (1/2lambda), MRT and AUMC were significantly higher in febrile rabbits. It is concluded that, although experimental infection had an effect on the disposition kinetics of cefepime in healthy and febrile rabbits, this was not sufficiently pronounced to require alteration of the dosage during disease.
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Affiliation(s)
- A M Abd El-Aty
- Department of Pharmacology, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt.
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37
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Kim HY, Kim IK, Shim JH, Kim YC, Han TH, Chung KC, Kim PI, Oh BT, Kim IS. Removal of alachlor and pretilachlor by laboratory-synthesized zerovalent iron in pesticide formulation solution. Bull Environ Contam Toxicol 2006; 77:826-33. [PMID: 17219301 DOI: 10.1007/s00128-006-1218-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2006] [Accepted: 11/16/2006] [Indexed: 05/13/2023]
Affiliation(s)
- H Y Kim
- Department of Agricultural Chemistry, BK21 Hazard Material Management Group, Institute of Agricultural Science and Technology, College of Agriculture and Life Sciences, Chonnam National University, Gwangju, Republic of Korea, 500-757
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Khay S, Abd El-Aty AM, Choi JH, Choi JT, Lim KT, Shim JH. Methomyl residue on Chinese cabbage grown under greenhouse conditions. Bull Environ Contam Toxicol 2006; 77:516-20. [PMID: 17123010 DOI: 10.1007/s00128-006-1094-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2006] [Accepted: 08/28/2006] [Indexed: 05/12/2023]
Affiliation(s)
- S Khay
- Natural Products Chemistry Laboratory, Institute of Agricultural Science and Technology, Chonnam National University, 300 Yong-Bong Dong, Buk-Ku, Gwangju 500-757, Republic of Korea
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Goudah A, Shin HC, Shim JH, Abd El-Aty AM. Characterization of the relationship between serum and milk residue disposition of ceftriaxone in lactating ewes. J Vet Pharmacol Ther 2006; 29:307-12. [PMID: 16846468 DOI: 10.1111/j.1365-2885.2006.00749.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [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: 11/25/2022]
Abstract
The present study was planned to investigate the serum disposition kinetics and the pattern of ceftriaxone elimination in milk and urine of lactating ewes (n = 6) following i.v. and i.m. administration. A crossover study was carried out in two phases separated by 15 days. Ceftriaxone was administered at a dosage of 10 mg/kg b.w. in all animals. Serum, milk and urine samples were collected between 0 and 72 h and a modified agar diffusion bioassay method was used to determine the percentage of protein binding and to measure serum, urine and milk concentrations of ceftriaxone. The drug was detected between 5 min and 48 h postdosing. Concentrations of 0.56 (10 h) and 0.52 (12 h), 0.22 (10 h) and 0.19 (12 h), and 2.18 (24 h) and 2.11 (48 h) mug/mL were measured in serum, milk and urine following i.v. and i.m. administration, respectively. Individual pharmacokinetic parameters were determined by fitting a two-compartment model to the serum and one-compartment open model to the milk concentration-time profiles. After i.v. dosing, the elimination rate constant and elimination half-life were 0.4 +/- 0.05/h and 1.75 +/- 0.02 h, respectively. The volume of distribution at steady state (V(dss)) of 0.28 +/- 0.15 L/kg reflected limited extracellular distribution of the drug with total body clearance (Cl(tot)) of 0.14 +/- 0.10 L/h/kg. Following i.m. administration, the mean T(max obs), C(max obs), t(1/2el) and AUC values for serum data were: 0.75 h, 23.16 +/- 2.94 microg/mL, 1.77 +/- 0.24 h and 67.55 +/- 6.51 microgxh/mL, respectively. For milk the data were: 1.0 h, 8.15 +/- 0.71 mug/mL, 2.2 +/- 0.34 h and 26.6 +/- 5.14 microgxh/mL, respectively. The i.m. bioavailability was 83.6% and the binding percentage of ceftriaxone to serum protein was 33%. Concentrations of ceftriaxone in milk produced by clinically normal mammary glands of ewes were consistently lower than in serum; the kinetic value AUC(milk)/AUC(serum) and C(max milk)/C(max serum) ratios was<0.4. These low values indicated poor distribution and penetration of ceftriaxone from the bloodstream to the mammary gland of lactating ewes following both routes.
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Affiliation(s)
- A Goudah
- Department of Pharmacology, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt
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40
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Kang CA, Kim MR, Shen JY, Cho IK, Park BJ, Kim IS, Shim JH. Supercritical fluid extraction for liquid chromatographic determination of pyrazosulfuron-ethyl in soils. Bull Environ Contam Toxicol 2006; 76:745-51. [PMID: 16786443 DOI: 10.1007/s00128-006-0983-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2005] [Accepted: 03/08/2006] [Indexed: 05/10/2023]
Affiliation(s)
- C A Kang
- Division of Applied Bioscience and Biotechnology, Institute of Agricultural Science and Technology, College of Agriculture and Life Science, Chonnam National University, Gwangju, South Korea
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Kim MR, Abd El-Aty AM, Kim IS, Shim JH. Determination of volatile flavor components in danggui cultivars by solvent free injection and hydrodistillation followed by gas chromatographic–mass spectrometric analysis. J Chromatogr A 2006; 1116:259-64. [PMID: 16620859 DOI: 10.1016/j.chroma.2006.03.060] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [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: 12/13/2005] [Revised: 02/20/2006] [Accepted: 03/14/2006] [Indexed: 11/23/2022]
Abstract
The rhizome of Angelica gigas Nakai, Angelica sinensis Diels and Angelica acutiloba Kitagawa (Umbelliferae) were chopped and extracted by hydrodistillation (HD) and solvent free solid injector (SFSI) methods to obtain the volatile compounds that were then characterized and identified by gas chromatography-mass spectrometry (GC/MS). SFSI extraction yielded a generally higher amount of volatile compounds than that produced by HD. A total of 48 components [including terpenes (8), aldehydes (4), alcohol (2), coumarins (9), Phthalide (3), acids (2) and sterols (2)] were identified by SFSI and gas chromatography-mass spectrometry from the three species of danggui cultivars, whereas, 24-essential oil was obtained by HD for Korean danggui only. According to these analyses, several coumarin derivatives such as decursinol angelate (16.83%) and decursin (29.34%) were found to be the dominant ones, followed by lomatin (10.25%) and marmesin (9.33%) in Korean danggui. Furfural and butylidene phthalide were the main components in Japanese in addition to butylidene dihydro-phthalide in Chinese danggui. Some parameters affecting the extraction efficiency such as injector temperature, injection time and pre-heating time were optimized. The results showed that the SFSI-method gave a higher yield of components with higher molecular mass than hydrodistillation. SFSI required little time to prepare the sample, little sample mass and a small quantity of organic solvent was needed. It can be concluded that analysis of volatile flavor compounds by SFSI in combination with gas chromatography/mass spectrometry is a suitable monitoring technique to differentiate danggui cultivars.
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Affiliation(s)
- M R Kim
- Natural Products Chemistry Laboratory, Institute of Agricultural Science and Technology, College of Agriculture and Life Science, Chonnam National University, 300 Yong-Bong Dong, Buk-Ku, Gwangju 500-757, South Korea
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Park BJ, Kyung KS, Choi JH, Im GJ, Kim IS, Shim JH. Environmental fate of the herbicide molinate in a rice-paddy-soil lysimeter. Bull Environ Contam Toxicol 2005; 75:937-44. [PMID: 16400582 DOI: 10.1007/s00128-005-0840-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2004] [Accepted: 08/26/2005] [Indexed: 05/06/2023]
Affiliation(s)
- B J Park
- Pesticide Safety Division, National Institute of Agricultural Science and Technology, Rural Development Administration, Suwon, South Korea
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Chen GX, Kim HS, Shim JH, Yoon JS. Role of Epoxy Groups on Clay Surface in the Improvement of Morphology of Poly(l-lactide)/Clay Composites. Macromolecules 2005. [DOI: 10.1021/ma0488515] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Guang-Xin Chen
- Department of Polymer Science and Engineering, Inha University, Incheon 402-751, Korea
| | - Hun-Sik Kim
- Department of Polymer Science and Engineering, Inha University, Incheon 402-751, Korea
| | - Jae-Hun Shim
- Department of Polymer Science and Engineering, Inha University, Incheon 402-751, Korea
| | - Jin-San Yoon
- Department of Polymer Science and Engineering, Inha University, Incheon 402-751, Korea
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Shim JH, Kang JS, Min BI. Electronic structures of RTe2 (R = La,Ce): a clue to the pressure-induced superconductivity in CeTe1.82. Phys Rev Lett 2004; 93:156406. [PMID: 15524914 DOI: 10.1103/physrevlett.93.156406] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2004] [Indexed: 05/24/2023]
Abstract
Electronic structures of RTe2 (R=La,Ce) have been investigated by using the local spin density approximation (LSDA) and the LSDA + U (U: on-site Coulomb interaction) band methods. Both LaTe2 and CeTe2 show the very similar Fermi surface nesting features along the [100] direction, which drive the charge-density wave (CDW) instability in the Te(1) sheets. The contribution near E(F) from Ce 4f states is negligible in agreement with the measured ARPES spectra. In the semimetallic CDW-distorted RTe2, both Te vacancy and pressure induce the charge transfer from Te(1) 5p to R 5d states, producing the enhanced density of states at E(F). We suggest that these increased self-doped Te(1) 5p hole carriers are responsible for the pressure-induced superconductivity in nonstoichiometric CeTe1.82.
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Affiliation(s)
- J H Shim
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
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Abstract
Prior electromyographic (EMG) analyses of the tennis serve have focused on the muscles in the hitting arm and shoulder region. This preliminary study aimed to examine the muscle activation patterns of selected lower trunk muscles during three different types of tennis serve--flat, topspin, and slice. Five male highly skilled tennis players completed 10 trials for each type of serve. Surface EMG electrodes were used to monitor the rectus abdominis (RA), external oblique (EO), internal oblique (IO), and lumbar erector spinae (ES) muscles. For each subject, the two trials with the highest self-reported ratings were analysed. Average EMG levels during each phase of a tennis serve for each muscle were analysed using a non-parametric ANOVA design. No major differences in muscle activation pattern were found across different serve types, and bilateral differences in muscle activation were more pronounced in RA and EO than in IO and ES muscles. The abdominal muscles were more active in the topspin than in the other two types of serves during the upward swing of the racket. An appreciable amount of abdominal/low back and bilateral co-activation was observed during certain phases of the serve. The co-activation of lower trunk muscles may help to stabilise the lumbar spine during the arch back and forward swing phases of the serve. The results reinforce the importance of abdominal and low back exercises in the strength and rehabilitation programs designed for tennis players.
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Affiliation(s)
- J W Chow
- Department of Exercise and Sport Sciences, University of Florida, Gainesville, Florida, USA
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Moon WS, Chung KH, Seol DJ, Park ES, Shim JH, Kim MN, Yoon JS. Antimicrobial effect of monomers and polymers with azole moieties. J Appl Polym Sci 2003. [DOI: 10.1002/app.13019] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Shim JH, Lee YS, Kim MR, Lee CJ, Kim IS. Use of the Keele injector for sample introduction for gas chromatographic analysis of vinclozolin in lettuces. J Chromatogr A 2003; 1015:233-7. [PMID: 14570334 DOI: 10.1016/s0021-9673(03)01260-3] [Citation(s) in RCA: 10] [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: 11/30/2022]
Abstract
We examined a Keele injector for sample introduction for gas chromatographic analysis of vinclozolin treated in lettuces. Samples in milligram quantity were introduced into a glass tube in a Keele injector at a gas chromatograph injection port. The glass tube was then crushed to allow the sample to carry onto a capillary column in a normal manner. The standard calibration curve for quantitative detection of vinclozolin was obtained by determining vinclozolin spiked in samples at variable concentrations. The calibration curve showed a linear response to vinclozolin ranging from 0.05 to 1.0 microg/g, giving a slope value of 174.8, the y-intercept value of -2.8146 and the mean r2-value of 0.9994. Limit of quantification for vinclozolin was 0.05 microg/g by this method, comparable to 0.01 microg/g by a normal injector. When samples treated previously with vinclozolin were determined by the Keele injector, vinclozolin was found to be about 30% lower as compared to a normal method, suggesting about 70% recovery of the spiked vinclozolin by the Keele injector. From these results, the Keele injector was suggested to be potential for sample introduction in gas chromatographic analysis of vinclozolin in lettuce samples.
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Affiliation(s)
- J H Shim
- Division of Applied Bioscience and Biotechnology, Institute of Agricultural Science and Technology, College of Agriculture and Life Science, Chonnam National University, Gwangju 500-757, South Korea.
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Lee CY, Lee DE, Hong YK, Shim JH, Jeong CK, Joo J, Zang DS, Shim MG, Lee JJ, Cha JK, Yang HG. Matrix formalism of electromagnetic wave propagation through multiple layers in the near-field region: application to the flat panel display. Phys Rev E Stat Nonlin Soft Matter Phys 2003; 67:046605. [PMID: 12786507 DOI: 10.1103/physreve.67.046605] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2001] [Revised: 11/19/2002] [Indexed: 05/24/2023]
Abstract
We have developed an electromagnetic (EM) wave propagation theory through a single layer and multiple layers in the near-field and far-field regions, and have constructed a matrix formalism in terms of the boundary conditions of the EM waves. From the shielding efficiency (SE) against EM radiation in the near-field region calculated by using the matrix formalism, we propose that the effect of multiple layers yields enhanced shielding capability compared to a single layer with the same total thickness in conducting layers as the multiple layers. We compare the intensities of an EM wave propagating through glass coated with conducting indium tin oxide (ITO) on one side and on both sides, applying it to the electromagnetic interference (EMI) shielding filter in a flat panel display such as a plasma display panel (PDP). From the measured intensities of EMI noise generated by a PDP loaded with ITO coated glass samples, the two-side coated glass shows a lower intensity of EMI noise compared to the one-side coated glass. The result confirms the enhancement of the SE due to the effect of multiple layers, as expected in the matrix formalism of EM wave propagation in the near-field region. In the far-field region, the two-side coated glass with ITO in multiple layers has a higher SE than the one-side coated glass with ITO, when the total thickness of ITO in both cases is the same.
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Affiliation(s)
- C Y Lee
- Department of Physics, Korea University, Seoul 136-701, Korea
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Lee SJ, Cho YS, Cho MC, Shim JH, Lee KA, Ko KK, Choe YK, Park SN, Hoshino T, Kim S, Dinarello CA, Yoon DY. Both E6 and E7 oncoproteins of human papillomavirus 16 inhibit IL-18-induced IFN-gamma production in human peripheral blood mononuclear and NK cells. J Immunol 2001; 167:497-504. [PMID: 11418688 DOI: 10.4049/jimmunol.167.1.497] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Cervical carcinoma is the predominant cancer among malignancies in women throughout the world, and human papillomavirus (HPV) 16 is the most common agent linked to human cervical carcinoma. The present study was performed to investigate the mechanisms of immune escape in HPV-induced cervical cancer cells. The presence of HPV oncoproteins E6 and E7 in the extracellular fluids of HPV-containing cervical cancer cell lines SiHa and CaSki was demonstrated by ELISA. The effect of HPV 16 oncoproteins E6 and E7 on the production of IFN-gamma by IL-18 was assessed. E6 and E7 proteins reduced IL-18-induced IFN-gamma production in both primary PBMCs and the NK0 cell line. FACS analysis revealed that the viral oncoproteins reduced the binding of IL-18 to its cellular surface receptors on NK0 cells, whereas there was no effect of oncoproteins on IL-1 binding to its surface IL-1 receptors on D10S, a subclone of the murine Th cell D10.G4.1. In vitro pull-down assays also revealed that the viral oncoproteins and IL-18 bound to IL-18R alpha-chain competitively. These results suggest that the extracellular HPV 16 E6 and E7 proteins may inhibit IL-18-induced IFN-gamma production locally in HPV lesions through inhibition of IL-18 binding to its alpha-chain receptor. Down-modulation of IL-18-induced immune responses by HPV oncoproteins may contribute to viral pathogenesis or carcinogenesis.
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MESH Headings
- Adjuvants, Immunologic/metabolism
- Adjuvants, Immunologic/physiology
- Binding, Competitive/immunology
- Cell Line
- Cell-Free System/chemistry
- Cell-Free System/metabolism
- Cells, Cultured
- Humans
- Interferon-gamma/antagonists & inhibitors
- Interferon-gamma/biosynthesis
- Interleukin-1/metabolism
- Interleukin-18/antagonists & inhibitors
- Interleukin-18/metabolism
- Interleukin-18/physiology
- Interleukin-18 Receptor alpha Subunit
- Killer Cells, Natural/immunology
- Killer Cells, Natural/metabolism
- Leukocytes, Mononuclear/immunology
- Leukocytes, Mononuclear/metabolism
- Oncogene Proteins, Viral/metabolism
- Oncogene Proteins, Viral/physiology
- Papillomaviridae/immunology
- Papillomavirus E7 Proteins
- Protein Binding/immunology
- Receptors, Interleukin/antagonists & inhibitors
- Receptors, Interleukin/metabolism
- Receptors, Interleukin-1/metabolism
- Receptors, Interleukin-18
- Repressor Proteins
- Tumor Cells, Cultured
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Affiliation(s)
- S J Lee
- Laboratory of Cellular Biology, Korea Research Institute of Bioscience and Biotechnology, Taejon, Korea
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Shim JH, Wall M, Benkovic SJ, Díaz N, Suárez D, Merz KM. Evaluation of the catalytic mechanism of AICAR transformylase by pH-dependent kinetics, mutagenesis, and quantum chemical calculations. J Am Chem Soc 2001; 123:4687-96. [PMID: 11457277 DOI: 10.1021/ja010014k] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The catalytic mechanism of 5-aminoimidazole-4-carboxamide ribonucleotide transformylase (AICAR Tfase) is evaluated with pH dependent kinetics, site-directed mutagenesis, and quantum chemical calculations. The chemistry step, represented by the burst rates, was not pH-dependent, which is consistent with our proposed mechanism that the 4-carboxamide of AICAR assists proton shuttling. Quantum chemical calculations on a model system of 5-amino-4-carboxamide imidazole (AICA) and formamide using the B3LYP/6-31G level of theory confirmed that the 4-carboxamide participated in the proton-shuttling mechanism. The result also indicated that the amide-assisted mechanism is concerted such that the proton transfers from the 5-amino group to the formamide are simultaneous with nucleophilic attack by the 5-amino group. Because the process does not lead to a kinetically stable intermediate, the intramolecular proton transfer from the 5-amino group through the 4-carboxamide to the formamide proceeds in the same transition state. Interestingly, the calculations predicted that protonation of the N3 of the imidazole of AICA would reduce the energy barrier significantly. However, the pK(a) of the imidazole of AICAR was determined to be 3.23 +/- 0.01 by NMR titration, and AICAR is likely to bind to the enzyme with its imidazole in the free base form. An alternative pathway was suggested by modeling Lys266 to have a hydrogen-bonding interaction with the N3 of the imidazole of AICAR. Lys266 has been implicated in catalysis based on mutagenesis studies and the recent X-ray structure of AICAR Tfase. The quantum chemical calculations on a model system that contains AICA complexed with CH3NH3+ as a mimic of the Lys residue confirmed that such an interaction lowered the activation energy of the reaction and likewise implicated the 4-carboxamide. To experimentally verify this hypothesis, we prepared the K266R mutant and found that its kcat is reduced by 150-fold from that of the wild type without changes in substrate and cofactor Km values. The kcat-pH profile indicated virtually no pH-dependence in the pH range 6-10.5. The results suggest that the ammonium moiety of Lys or Arg is important in catalysis, most likely acting as a general acid catalyst with a pK(a) value greater than 10.5. The H267A mutant was also prepared since His267 has been found in the active site and implicated in catalysis. The mutant enzyme showed no detectable activity while retaining its binding affinity for substrate, indicating that it plays a critical role in catalysis. We propose that His267 interacts with Lys266 to aid in the precise positioning of the general acid catalyst to the N3 of the imidazole of AICAR.
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Affiliation(s)
- J H Shim
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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