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Huang H, Lee SJ, Ikeda Y, Taniguchi T, Takahama M, Kao CC, Fujita M, Lee JS. Two-Dimensional Superconducting Fluctuations Associated with Charge-Density-Wave Stripes in La_{1.87}Sr_{0.13}Cu_{0.99}Fe_{0.01}O_{4}. Phys Rev Lett 2021; 126:167001. [PMID: 33961453 DOI: 10.1103/physrevlett.126.167001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 12/14/2020] [Accepted: 03/22/2021] [Indexed: 06/12/2023]
Abstract
The presence of a small concentration of in-plane Fe dopants in La_{1.87}Sr_{0.13}Cu_{0.99}Fe_{0.01}O_{4} is known to enhance stripelike spin and charge density wave (SDW and CDW) order and suppress the superconducting T_{c}. Here, we show that it also induces highly two-dimensional superconducting correlations that have been argued to be the signatures of a new form of superconducting order, the so-called pair density wave (PDW) order. In addition, using resonant soft x-ray scattering, we find that the two-dimensional superconducting fluctuation is strongly associated with the CDW stripe. In particular, the PDW signature first appears when the correlation length of the CDW stripe grows over eight times the lattice unit (∼8a). These results provide critical conditions for the formation of the PDW order.
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Affiliation(s)
- H Huang
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - S-J Lee
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Y Ikeda
- Institute for Materials Research, Tohoku University, Katahira 2-1-1, Sendai 980-8577, Japan
| | - T Taniguchi
- Institute for Materials Research, Tohoku University, Katahira 2-1-1, Sendai 980-8577, Japan
| | - M Takahama
- Institute for Materials Research, Tohoku University, Katahira 2-1-1, Sendai 980-8577, Japan
| | - C-C Kao
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - M Fujita
- Institute for Materials Research, Tohoku University, Katahira 2-1-1, Sendai 980-8577, Japan
| | - J-S Lee
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
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2
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Kao CC, Yang ZY, Cheng YW, Chen WL. Examining the association between serum free fatty acids and blood levels of testosterone. J Hum Nutr Diet 2020; 34:334-344. [PMID: 33089908 DOI: 10.1111/jhn.12828] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 07/08/2020] [Revised: 09/26/2020] [Accepted: 09/28/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND Multiple studies have uncovered the effects that ingested fat has on human blood levels of testosterone. Yet, few reports have discussed the effect of circulating serum free fatty acids (FFAs). The present study aimed to explore the relationship between serum free fatty acids and blood levels of testosterone. METHODS In total, 5719 adults were pooled from the database of the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2012. Based on multivariable-linear regression models, we employed a total of 30 FFAs to interpret the relationship of FFAs with blood levels of testosterone. Two models with covariate adjustments were designated for further evaluation and analysis. RESULTS Capric acid [β = -0.014, 95% confidence interval (CI) = -0.023, -0.004, P = 0.005], myristic acid (β = -0.001, 95% CI = -0.001, 0.000, P ≤ 0.001), pentadecanoic acid (β = -0.013, 95% CI = -0.018, -0.008, P ≤ 0.001), margaric acid (β = -0.011, 95% CI = -0.017, -0.005, P ≤ 0.001) and alpha-linolenic acid (β = -0.001, 95% CI = -0.002, 0.000, P = 0.004) in the fully adjusted model were significantly negatively correlated with the testosterone level inh obese men. In the fully adjusted model for the female analysis, myristic acid, pentadecanoic acid, palmitic acid, margaric acid, stearic acid, myristoleic acid, oleic acid, nervonic acid and alpha-linolenic acid were found significantly associated with the testosterone level. CONCLUSIONS Our findings indicate a significant negative correlation between serum FFAs and blood levels of testosterone. Furthermore, we reveal the essentiality of serum FFAs and their potential effects on the reduction of testosterone levels.
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Affiliation(s)
- C-C Kao
- Division of Family Medicine, Department of Family and Community Medicine, Tri-Service General Hospital, Taiwan, Republic of China.,School of Medicine, National Defense Medical Center, Taiwan, Republic of China
| | - Z-Y Yang
- Division of Family Medicine, Department of Family and Community Medicine, Tri-Service General Hospital, Taiwan, Republic of China.,School of Medicine, National Defense Medical Center, Taiwan, Republic of China
| | - Y-W Cheng
- Division of Family Medicine, Department of Family and Community Medicine, Tri-Service General Hospital, Taiwan, Republic of China.,School of Medicine, National Defense Medical Center, Taiwan, Republic of China
| | - W-L Chen
- Division of Family Medicine, Department of Family and Community Medicine, Tri-Service General Hospital, Taiwan, Republic of China.,School of Medicine, National Defense Medical Center, Taiwan, Republic of China.,Division of Geriatric Medicine, Department of Family and Community Medicine, Tri-Service General Hospital, Taiwan, Republic of China.,Department of Biochemistry, National Defense Medical Center, Taiwan, Republic of China
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3
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Parulekar AD, Wang T, Li GW, Hoang V, Kao CC. Pectoralis muscle area is associated with bone mineral density and lung function in lung transplant candidates. Osteoporos Int 2020; 31:1361-1367. [PMID: 32170395 DOI: 10.1007/s00198-020-05373-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 03/02/2020] [Indexed: 10/24/2022]
Abstract
UNLABELLED Loss of bone mineral density and skeletal muscle area are linked in lung transplant patients. This loss is greater in patients with restrictive compared with obstructive lung diseases. INTRODUCTION Sarcopenia and osteoporosis are associated with aging and chronic illnesses and may be linked in patients with advanced lung disease. Pectoralis muscle index (PMI) quantitated on computed tomography (CT) of the chest can be used to measure skeletal muscle mass. This study aimed to determine the relationship of PMI to clinical parameters including bone mineral density (BMD) in candidates for lung transplantation. METHODS A retrospective review of transplant candidates at a single center was performed. Demographic, anthropomorphic, and clinical data were recorded. Pectoralis muscle area (PMA) was determined on an axial slice from a chest CT. PMI was calculated as the PMA divided by height squared. BMD was obtained from routine dual-energy X-ray absorptiometry (DXA) scan. RESULTS In 226 included patients, mean PMI was 8.2 ± 3.0 cm2/m2 in males and 6.1 ± 2.1 cm2/m2 in females. Osteopenia was present in 44.4%, and 23.2% of patients had osteoporosis. Patients with obstructive lung disease had lower body mass index (22.0 ± 4.9 versus 27.9 ± 4.9 kg/m2, p < 0.001), PMI (6.0 ± 2.3 versus 8.2 ± 2.8 cm2/m2, p < 0.001), and BMD (- 2.3 ± 1.1 versus - 1.3 ± 1.1, p < 0.001) compared with patients with restrictive lung disease. PMI was a significant predictor of BMD (β = 0.16, p < 0.001). CONCLUSION The association between muscle area and BMD in lung transplant candidates suggests that similar mechanisms may underlie the development of both. Differences in PMI and BMD in patients with obstructive versus restrictive lung disease may result from differences in respiratory physiology or disease processes.
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Affiliation(s)
- A D Parulekar
- Section of Pulmonary, Critical Care, and Sleep, Department of Medicine, Baylor College of Medicine, 6620 Main Street, Houston, TX, 77030, USA
| | - T Wang
- Department of Medicine, Baylor College of Medicine, Houston, TX, USA
| | - G W Li
- Section of Pulmonary, Critical Care, and Sleep, Department of Medicine, Baylor College of Medicine, 6620 Main Street, Houston, TX, 77030, USA
| | - V Hoang
- Section of Pulmonary, Critical Care, and Sleep, Department of Medicine, Baylor College of Medicine, 6620 Main Street, Houston, TX, 77030, USA
| | - C C Kao
- Section of Pulmonary, Critical Care, and Sleep, Department of Medicine, Baylor College of Medicine, 6620 Main Street, Houston, TX, 77030, USA.
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Wen JJ, Huang H, Lee SJ, Jang H, Knight J, Lee YS, Fujita M, Suzuki KM, Asano S, Kivelson SA, Kao CC, Lee JS. Observation of two types of charge-density-wave orders in superconducting La 2-xSr xCuO 4. Nat Commun 2019; 10:3269. [PMID: 31332190 PMCID: PMC6646325 DOI: 10.1038/s41467-019-11167-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 06/13/2019] [Indexed: 11/26/2022] Open
Abstract
The discovery of charge- and spin-density-wave (CDW/SDW) orders in superconducting cuprates has altered our perspective on the nature of high-temperature superconductivity (SC). However, it has proven difficult to fully elucidate the relationship between the density wave orders and SC. Here, using resonant soft X-ray scattering, we study the archetypal cuprate La2-xSrxCuO4 (LSCO) over a broad doping range. We reveal the existence of two types of CDW orders in LSCO, namely CDW stripe order and CDW short-range order (SRO). While the CDW-SRO is suppressed by SC, it is partially transformed into the CDW stripe order with developing SDW stripe order near the superconducting Tc. These findings indicate that the stripe orders and SC are inhomogeneously distributed in the superconducting CuO2 planes of LSCO. This further suggests a new perspective on the putative pair-density-wave order that coexists with SC, SDW, and CDW orders. To fully elucidate the relationship between density wave orders and superconductivity in high-Tc cuprates remains difficult. Here, the authors reveal two types of charge-density-wave orders and their intertwined relationship with spin-density-wave order and superconductivity in La2-xSrxCuO4.
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Affiliation(s)
- J-J Wen
- SLAC National Accelerator Laboratory, Menlo Park, California, 94025, USA
| | - H Huang
- SLAC National Accelerator Laboratory, Menlo Park, California, 94025, USA
| | - S-J Lee
- SLAC National Accelerator Laboratory, Menlo Park, California, 94025, USA
| | - H Jang
- SLAC National Accelerator Laboratory, Menlo Park, California, 94025, USA.,PAL-XFEL, Pohang Accelerator Laboratory, Gyeongbuk, 37673, South Korea
| | - J Knight
- SLAC National Accelerator Laboratory, Menlo Park, California, 94025, USA
| | - Y S Lee
- SLAC National Accelerator Laboratory, Menlo Park, California, 94025, USA.,Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA
| | - M Fujita
- Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan
| | - K M Suzuki
- Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan
| | - S Asano
- Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan
| | - S A Kivelson
- Departments of Physics, Stanford University, Stanford, CA, 94305, USA
| | - C-C Kao
- SLAC National Accelerator Laboratory, Menlo Park, California, 94025, USA
| | - J-S Lee
- SLAC National Accelerator Laboratory, Menlo Park, California, 94025, USA.
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5
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Kao CC, Liu JS, Lin MH, Hsu CY, Chang FC, Lin YC, Chen HH, Chen TW, Hsu CC, Wu MS. Impact of mTOR Inhibitors on Cancer Development in Kidney Transplantation Recipients: A Population-Based Study. Transplant Proc 2016; 48:900-4. [PMID: 27234763 DOI: 10.1016/j.transproceed.2016.01.017] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 01/07/2016] [Accepted: 01/21/2016] [Indexed: 10/21/2022]
Abstract
BACKGROUND The mammalian target of rapamycin (mTOR) inhibitor is an immunosuppressive drug used in kidney transplantation. Whether the mTOR inhibitor is associated with reduced risk of cancer development and mortality after kidney transplantation is controversial. METHODS We conducted a nationwide population-based study. Patients who did not have malignancy history and received kidney transplantation between 2010 and 2013 were enrolled. Recipients who had mTOR inhibitors (n = 430) for more than 30 days comprised the study group; 1720 recipients who did not have mTOR inhibitors comprised the control group. The primary outcome is the development of cancer after kidney transplantation. These patients were followed until the first-time admission with diagnosis of cancer, death, or the end of 2014. A Cox proportional-hazard model was used to determine the risk of cancer development and all-cause mortality. RESULTS During the 35-month median duration of observation, there were 16 and 61 patients with cancer development in the study group and the control group, respectively. The cancer incidence was 12.8 and 12.4 per 1000 person-years. There were 10 and 135 mortality cases, with the incidence rate of 7.8 and 26.9 per 1000 person-years. After multivariable adjustment, the mTOR inhibitors users were not associated with reduced risk of new cancer development as compared with control (hazard ratio [HR], 0.86; 95% confidence interval [CI], 0.46-1.60; P = .63), nor risk of all-cause mortality (HR, 0.70; 95% CI, 0.33-1.46; P = .34). CONCLUSIONS The use of mTOR inhibitors was not associated with a reduction in the risk of cancer development and all-cause mortality in kidney transplantation recipients.
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Affiliation(s)
- C-C Kao
- Division of Nephrology, Department of Internal Medicine, Taipei Medical University Hospital, Taipei, Taiwan; Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Division of Nephrology, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - J-S Liu
- Division of Geriatrics and Gerontology, Institute of Population Health Sciences, National Health Research Institutes, Zhunan, Taiwan
| | - M-H Lin
- Division of Geriatrics and Gerontology, Institute of Population Health Sciences, National Health Research Institutes, Zhunan, Taiwan
| | - C-Y Hsu
- Division of Nephrology, Department of Internal Medicine, Taipei Medical University Hospital, Taipei, Taiwan
| | - F-C Chang
- Division of Nephrology, Department of Internal Medicine, Taipei Medical University Hospital, Taipei, Taiwan; Division of Nephrology, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Y-C Lin
- Division of Nephrology, Department of Internal Medicine, Taipei Medical University Hospital, Taipei, Taiwan; Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Division of Nephrology, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - H-H Chen
- Division of Nephrology, Department of Internal Medicine, Taipei Medical University Hospital, Taipei, Taiwan; Division of Nephrology, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - T-W Chen
- Division of Nephrology, Department of Internal Medicine, Taipei Medical University Hospital, Taipei, Taiwan; Division of Nephrology, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - C-C Hsu
- Division of Geriatrics and Gerontology, Institute of Population Health Sciences, National Health Research Institutes, Zhunan, Taiwan; Department of Health Services Administration, China Medical University and Hospital, Taichung, Taiwan
| | - M-S Wu
- Division of Nephrology, Department of Internal Medicine, Taipei Medical University Hospital, Taipei, Taiwan; Division of Nephrology, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
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6
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Jang H, Kang BY, Cho BK, Hashimoto M, Lu D, Burns CA, Kao CC, Lee JS. Observation of Orbital Order in the Half-Filled 4f Gd Compound. Phys Rev Lett 2016; 117:216404. [PMID: 27911536 DOI: 10.1103/physrevlett.117.216404] [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: 05/03/2016] [Indexed: 06/06/2023]
Abstract
Half-filled electron systems, even with the maximized spin angular moment, have been given little attention because of their zero-orbital angular moment according to Hund's rule. Nevertheless, there are several measurements that show evidence of a nonzero orbital moment as well as spin-orbit coupling. Here we report for the first time the orbital order in a half-filled 4f-electron system GdB_{4}, using the resonant soft x-ray scattering at Gd M_{4,5}-edges. Furthermore, we discovered that the development of this orbital order is strongly coupled with the antiferromagnetic spin order. These results clearly demonstrate that even in half-filled electron systems the orbital angular moment can be an important parameter to describe material properties, and may provide significant opportunities for tailoring new correlated electron systems.
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Affiliation(s)
- H Jang
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - B Y Kang
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - B K Cho
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - M Hashimoto
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - D Lu
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - C A Burns
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Department of Physics, Western Michigan University, Kalamazoo, Michigan 49008, USA
| | - C-C Kao
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - J-S Lee
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
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7
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Gerber S, Jang H, Nojiri H, Matsuzawa S, Yasumura H, Bonn DA, Liang R, Hardy WN, Islam Z, Mehta A, Song S, Sikorski M, Stefanescu D, Feng Y, Kivelson SA, Devereaux TP, Shen ZX, Kao CC, Lee WS, Zhu D, Lee JS. Three-dimensional charge density wave order in YBa2Cu3O6.67 at high magnetic fields. Science 2015; 350:949-52. [PMID: 26541608 DOI: 10.1126/science.aac6257] [Citation(s) in RCA: 238] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 09/30/2015] [Indexed: 11/02/2022]
Abstract
Charge density wave (CDW) correlations have been shown to universally exist in cuprate superconductors. However, their nature at high fields inferred from nuclear magnetic resonance is distinct from that measured with x-ray scattering at zero and low fields. We combined a pulsed magnet with an x-ray free-electron laser to characterize the CDW in YBa2Cu3O6.67 via x-ray scattering in fields of up to 28 tesla. While the zero-field CDW order, which develops at temperatures below ~150 kelvin, is essentially two dimensional, at lower temperature and beyond 15 tesla, another three-dimensionally ordered CDW emerges. The field-induced CDW appears around the zero-field superconducting transition temperature; in contrast, the incommensurate in-plane ordering vector is field-independent. This implies that the two forms of CDW and high-temperature superconductivity are intimately linked.
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Affiliation(s)
- S Gerber
- Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, CA 94025, USA
| | - H Jang
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - H Nojiri
- Institute for Materials Research, Tohoku University, Katahira 2-1-1, Sendai, 980-8577, Japan
| | - S Matsuzawa
- Institute for Materials Research, Tohoku University, Katahira 2-1-1, Sendai, 980-8577, Japan
| | - H Yasumura
- Institute for Materials Research, Tohoku University, Katahira 2-1-1, Sendai, 980-8577, Japan
| | - D A Bonn
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada. Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada
| | - R Liang
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada. Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada
| | - W N Hardy
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada. Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada
| | - Z Islam
- The Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA
| | - A Mehta
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - S Song
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - M Sikorski
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - D Stefanescu
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Y Feng
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - S A Kivelson
- Geballe Laboratory for Advanced Materials, Departments of Physics and Applied Physics, Stanford University, Stanford, CA 94305, USA
| | - T P Devereaux
- Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, CA 94025, USA
| | - Z-X Shen
- Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, CA 94025, USA. Geballe Laboratory for Advanced Materials, Departments of Physics and Applied Physics, Stanford University, Stanford, CA 94305, USA
| | - C-C Kao
- SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - W-S Lee
- Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, CA 94025, USA.
| | - D Zhu
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
| | - J-S Lee
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
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8
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Yeh YC, Hsu YC, Chao A, Wu VC, Sheng WH, Kao CC, Cheng YJ. The effect of endotoxin adsorber hemoperfusion on microcirculation in patients with severe sepsis and septic shock. Intensive Care Med Exp 2015. [PMCID: PMC4798303 DOI: 10.1186/2197-425x-3-s1-a810] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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9
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Gerber S, Kim KW, Zhang Y, Zhu D, Plonka N, Yi M, Dakovski GL, Leuenberger D, Kirchmann PS, Moore RG, Chollet M, Glownia JM, Feng Y, Lee JS, Mehta A, Kemper AF, Wolf T, Chuang YD, Hussain Z, Kao CC, Moritz B, Shen ZX, Devereaux TP, Lee WS. Direct characterization of photoinduced lattice dynamics in BaFe2As2. Nat Commun 2015; 6:7377. [PMID: 26051704 PMCID: PMC4468847 DOI: 10.1038/ncomms8377] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Accepted: 04/29/2015] [Indexed: 11/16/2022] Open
Abstract
Ultrafast light pulses can modify electronic properties of quantum materials by perturbing the underlying, intertwined degrees of freedom. In particular, iron-based superconductors exhibit a strong coupling among electronic nematic fluctuations, spins and the lattice, serving as a playground for ultrafast manipulation. Here we use time-resolved X-ray scattering to measure the lattice dynamics of photoexcited BaFe2As2. On optical excitation, no signature of an ultrafast change of the crystal symmetry is observed, but the lattice oscillates rapidly in time due to the coherent excitation of an A1g mode that modulates the Fe–As–Fe bond angle. We directly quantify the coherent lattice dynamics and show that even a small photoinduced lattice distortion can induce notable changes in the electronic and magnetic properties. Our analysis implies that transient structural modification can be an effective tool for manipulating the electronic properties of multi-orbital systems, where electronic instabilities are sensitive to the orbital character of bands. In BaFe2As2, the lattice couples strongly to the magnetic and electronic degrees of freedom, providing a way to control them. Here, by means of time-resolved X-ray scattering, the authors measure rapid lattice oscillations, which can induce changes in the material's electronic and magnetic properties.
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Affiliation(s)
- S Gerber
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - K W Kim
- Department of Physics, Chungbuk National University, 52 Naesudong-ro, Heungdeok-gu, Cheongju 361-763, Korea
| | - Y Zhang
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, 2575 Sand Hill Road, Menlo Park, California 94025, USA.,Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA
| | - D Zhu
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - N Plonka
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, 2575 Sand Hill Road, Menlo Park, California 94025, USA.,Departments of Physics and Applied Physics, Stanford University, 476 Lomita Mall, Stanford, California 94305, USA
| | - M Yi
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, 2575 Sand Hill Road, Menlo Park, California 94025, USA.,Departments of Physics and Applied Physics, Stanford University, 476 Lomita Mall, Stanford, California 94305, USA
| | - G L Dakovski
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - D Leuenberger
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - P S Kirchmann
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - R G Moore
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - M Chollet
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - J M Glownia
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - Y Feng
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - J-S Lee
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - A Mehta
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - A F Kemper
- Computational Research Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA
| | - T Wolf
- Institute for Solid State Physics, Karlsruhe Institute of Technology, Hermann-v.-Helmholtz-Platz 1, 76021 Karlsruhe, Germany
| | - Y-D Chuang
- Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA
| | - Z Hussain
- Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA
| | - C-C Kao
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - B Moritz
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - Z-X Shen
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, 2575 Sand Hill Road, Menlo Park, California 94025, USA.,Departments of Physics and Applied Physics, Stanford University, 476 Lomita Mall, Stanford, California 94305, USA
| | - T P Devereaux
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - W-S Lee
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, 2575 Sand Hill Road, Menlo Park, California 94025, USA
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10
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Wen Y, Lin X, Fan B, Ranjith-Kumar CT, Kao CC. The juxtamembrane sequence of the Hepatitis C virus polymerase can affect RNA synthesis and inhibition by allosteric polymerase inhibitors. Virus Genes 2015; 51:1-11. [PMID: 25895103 DOI: 10.1007/s11262-015-1199-4] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 04/09/2015] [Indexed: 12/21/2022]
Abstract
The Hepatitis C virus (HCV) RNA-dependent RNA polymerase (RdRp), nonstructural protein 5B (NS5B), is anchored in the membrane through a C-terminal helix. A sequence of ca. 12 residues that connects the catalytically competent portion of the RdRp and the C-terminal helix, the juxtamembrane sequence (JMS), has a poorly defined role in RdRp function in a large part since it is translated from a cis-acting RNA element (CRE) that is essential for HCV replication. Using a HCV replicon that transposed a second copy of CRE to the 3' UTR of the HCV replicon, we demonstrate that amino acid substitutions in the JMS were detrimental for HCV replicon replication. Substitutions in the JMS also resulted in a defect in de novo-initiated RNAs synthesis in vitro and in a cell-based reporter assay. A nonnucleoside inhibitor of the NS5B that binds to the catalytic pocket was less potent in inhibiting NS5B in the presence of JMS mutations. The JMS mutants exhibit reduced stability in thermodenaturation assays, suggesting that the JMS helps confer a more stable conformation to NS5B that could impact RNA synthesis.
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Affiliation(s)
- Y Wen
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, 47405, USA
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11
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12
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Lee JS, Xie YW, Sato HK, Bell C, Hikita Y, Hwang HY, Kao CC. Titanium dxy ferromagnetism at the LaAlO3/SrTiO3 interface. Nat Mater 2013; 12:703-706. [PMID: 23727948 DOI: 10.1038/nmat3674] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 04/29/2013] [Indexed: 06/02/2023]
Abstract
A number of recent transport and magnetization studies have shown signs of ferromagnetism in the LaAlO3/SrTiO3 heterostructure, an unexpected property with no bulk analogue in the constituent materials. However, no experiment thus far has provided direct information on the host of the magnetism. Here we report spectroscopic investigations of the magnetism using element-specific techniques, including X-ray magnetic circular dichroism and X-ray absorption spectroscopy, along with corresponding model calculations. We find direct evidence for in-plane ferromagnetic order at the interface, with Ti(3+) character in the dxy orbital of the anisotropic t2g band. These findings establish a striking example of emergent phenomena at oxide interfaces.
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Affiliation(s)
- J-S Lee
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
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13
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Running WE, Ni P, Kao CC, Reilly JP. Chemical reactivity of brome mosaic virus capsid protein. J Mol Biol 2012; 423:79-95. [PMID: 22750573 DOI: 10.1016/j.jmb.2012.06.031] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 06/01/2012] [Accepted: 06/20/2012] [Indexed: 12/12/2022]
Abstract
Viral particles are biological machines that have evolved to package, protect, and deliver the viral genome into the host via regulated conformational changes of virions. We have developed a procedure to modify lysine residues with S-methylthioacetimidate across the pH range from 5.5 to 8.5. Lysine residues that are not completely modified are involved in tertiary or quaternary structural interactions, and their extent of modification can be quantified as a function of pH. This procedure was applied to the pH-dependent structural transitions of brome mosaic virus (BMV). As the reaction pH increases from 5.5 to 8.5, the average number of modified lysine residues in the BMV capsid protein increases from 6 to 12, correlating well with the known pH-dependent swelling behavior of BMV virions. The extent of reaction of each of the capsid protein's lysine residues has been quantified at eight pH values using coupled liquid chromatography-tandem mass spectrometry. Each lysine can be assigned to one of three structural classes identified by inspection of the BMV virion crystal structure. Several lysine residues display reactivity that indicates their involvement in dynamic interactions that are not obvious in the crystal structure. The influence of several capsid protein mutants on the pH-dependent structural transition of BMV has also been investigated. Mutant H75Q exhibits an altered swelling transition accompanying solution pH increases. The H75Q capsids show increased reactivity at lysine residues 64 and 130, residues distal from the dimer interface occupied by H75, across the entire pH range.
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Affiliation(s)
- W E Running
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
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14
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Lee JS, Kao CC, Nelson CS, Jang H, Ko KT, Kim SB, Choi YJ, Cheong SW, Smadici S, Abbamonte P, Park JH. Fragile magnetic ground state in half-doped LaSr2Mn2O7. Phys Rev Lett 2011; 107:037206. [PMID: 21838401 DOI: 10.1103/physrevlett.107.037206] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Indexed: 05/31/2023]
Abstract
We investigated the orbital and antiferromagnetic ordering behaviors of the half-doped bilayer manganite La(2-2x)Sr(1+2x)Mn2O7 (x ≃ 0.5) by using Mn L(2,3)-edge resonant soft x-ray scattering. Resonant soft x-ray scattering reveals the CE-type orbital order below T(oo) ≃ 220 K, which shows partial melting behavior below T(m) ≃ 165 K. We also found coexistence CE- and A-type antiferromagnetic orders. Both orders involve the CE-type orbital order with nearly the same orbital character and are coupled with each other. These results manifest that the ground state with the CE-type antiferromagnetic order is easily susceptible to destabilization into the A-type one even with a small fluctuation of the doping level, as suggested by the extremely narrow magnetic phase boundaries at x ≃ 0.5±0.005.
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Affiliation(s)
- J-S Lee
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
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15
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Kao CC, Lian JD, Chou MC, Chang HR, Yang SF. Tumor necrosis factor alpha promoter polymorphism in posttransplantation diabetes mellitus of renal transplant recipients. Transplant Proc 2011; 42:3559-61. [PMID: 21094815 DOI: 10.1016/j.transproceed.2010.06.032] [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] [Received: 10/18/2009] [Revised: 03/30/2010] [Accepted: 06/10/2010] [Indexed: 01/18/2023]
Abstract
Posttransplantation diabetes mellitus (PTDM) is a major complication in renal transplant recipients. Some studies have demonstrated that tumor necrosis factor alpha (TNF-α) expression and its genetic polymorphism are associated with diabetes mellitus. We investigated this association in Asian renal transplant recipients. Polymerase chain reaction-restriction-fragment length polymorphism was used to measure TNF-α G-238A and G-308A gene polymorphisms among 241 nonposttransplantation diabetic subjects and 73 PTDM patients. PTDM patients showed higher values of body weight and body mass index (BMI) than the non-PTDM group. However, no significant association was observed between TNF-α G-238A and TNF-α G-308A polymorphisms with PTDM incidence, gender, age at transplantation, follow-up duration, BMI, or type of immunosuppression.
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Affiliation(s)
- C-C Kao
- Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan
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16
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Lee JS, Arena DA, Yu P, Nelson CS, Fan R, Kinane CJ, Langridge S, Rossell MD, Ramesh R, Kao CC. Hidden magnetic configuration in epitaxial La(1-x) Sr(x) MnO3 films. Phys Rev Lett 2010; 105:257204. [PMID: 21231622 DOI: 10.1103/physrevlett.105.257204] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Indexed: 05/30/2023]
Abstract
We present an unreported magnetic configuration in epitaxial La(1-x) Sr(x) MnO3 (x ∼ 0.3) (LSMO) films grown on strontium titanate (STO). X-ray magnetic circular dichroism indicates that the remanent magnetic state of thick LSMO films is opposite to the direction of the applied magnetic field. Spectroscopic and scattering measurements reveal that the average Mn valence varies from mixed Mn(3+)/Mn(4+) to an enriched Mn3+ region near the STO interface, resulting in a compressive lattice along the a, b axis and a possible electronic reconstruction in the Mn e(g) orbital (d(3)z(2)-r(2). This reconstruction may provide a mechanism for coupling the Mn3+ moments antiferromagnetically along the surface normal direction, and in turn may lead to the observed reversed magnetic configuration.
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Affiliation(s)
- J-S Lee
- National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973, USA
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17
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Yu P, Lee JS, Okamoto S, Rossell MD, Huijben M, Yang CH, He Q, Zhang JX, Yang SY, Lee MJ, Ramasse QM, Erni R, Chu YH, Arena DA, Kao CC, Martin LW, Ramesh R. Interface ferromagnetism and orbital reconstruction in BiFeO3-La(0.7)Sr(0.3)MnO3 heterostructures. Phys Rev Lett 2010; 105:027201. [PMID: 20867733 DOI: 10.1103/physrevlett.105.027201] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2009] [Indexed: 05/12/2023]
Abstract
We report the formation of a novel ferromagnetic state in the antiferromagnet BiFeO3 at the interface with ferromagnet La(0.7)Sr(0.3)MnO3. Using x-ray magnetic circular dichroism at Mn and Fe L(2,3) edges, we discovered that the development of this ferromagnetic spin structure is strongly associated with the onset of a significant exchange bias. Our results demonstrate that the magnetic state is directly related to an electronic orbital reconstruction at the interface, which is supported by the linearly polarized x-ray absorption measurement at the oxygen K edge.
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Affiliation(s)
- P Yu
- Department of Physics, University of California, Berkeley, California 94720, USA.
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18
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Yang MH, Kao CC, Hsu KF. A series of images in localized fibrinolytic treatment for a patient with acute superior mesenteric artery thromboembolism. Acta Clin Belg 2008; 63:343-4. [PMID: 19186569 DOI: 10.1179/acb.2008.067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Affiliation(s)
- M-H Yang
- Department of Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, Republic of China
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19
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Huotari S, Hämäläinen K, Diamant R, Sharon R, Kao CC, Deutsch M. Intrashell electron-interaction-mediated photoformation of hollow atoms near threshold. Phys Rev Lett 2008; 101:043001. [PMID: 18764322 DOI: 10.1103/physrevlett.101.043001] [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: 11/26/2007] [Indexed: 05/26/2023]
Abstract
Double photoionization (DPI) of an atom by a single photon is a direct consequence of electron-electron interactions within the atom. We have measured the evolution of the K-shell DPI from threshold up in transition metals by high-resolution x-ray emission spectroscopy of the Kh alpha hypersatellites, photoexcited by monochromatized synchrotron radiation. The measured evolution of the single-to-double photoionization cross-section ratio with excitation energy was found to be universal. Theoretical fits suggest that near threshold DPI is predominantly a semiclassical knockout effect, rather than the purely quantum-mechanical shake-off observed at the infinite photon energy limit.
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Affiliation(s)
- S Huotari
- ESRF, 6 rue Jules Horowitz, B.P. 220, F-38043 Grenoble cedex, France
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20
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Shen Y, Watanabe T, Arena DA, Kao CC, Murphy JB, Tsang TY, Wang XJ, Carr GL. Nonlinear cross-phase modulation with intense single-cycle terahertz pulses. Phys Rev Lett 2007; 99:043901. [PMID: 17678365 DOI: 10.1103/physrevlett.99.043901] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2006] [Indexed: 05/16/2023]
Abstract
We have demonstrated nonlinear cross-phase modulation in electro-optic crystals using intense, single-cycle terahertz (THz) radiation. Individual THz pulses, generated by coherent transition radiation emitted by subpicosecond electron bunches, have peak energies of up to 100 microJ per pulse. The time-dependent electric field of the intense THz pulses induces cross-phase modulation in electro-optic crystals through the Pockels effect, leading to spectral shifting, broadening, and modulation of copropagating laser pulses. The observed THz-induced cross-phase modulation agrees well with a time-dependent phase-shift model.
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Affiliation(s)
- Y Shen
- National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973-5000, USA
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21
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Cai YQ, Chow PC, Restrepo OD, Takano Y, Togano K, Kito H, Ishii H, Chen CC, Liang KS, Chen CT, Tsuda S, Shin S, Kao CC, Ku W, Eguiluz AG. Low-energy charge-density excitations in MgB2: Striking interplay between single-particle and collective behavior for large momenta. Phys Rev Lett 2006; 97:176402. [PMID: 17155487 DOI: 10.1103/physrevlett.97.176402] [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: 05/07/2006] [Indexed: 05/12/2023]
Abstract
A sharp feature in the charge-density excitation spectra of single-crystal MgB2, displaying a remarkable cosinelike, periodic energy dispersion with momentum transfer (q) along the c* axis, has been observed for the first time by high-resolution nonresonant inelastic x-ray scattering (NIXS). Time-dependent density-functional theory calculations show that the physics underlying the NIXS data is strong coupling between single-particle and collective degrees of freedom, mediated by large crystal local-field effects. As a result, the small-q collective mode residing in the single-particle excitation gap of the B pi bands reappears periodically in higher Brillouin zones. The NIXS data thus embody a novel signature of the layered electronic structure of MgB2.
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Affiliation(s)
- Y Q Cai
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.
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Abstract
The crystal structure of the recombinant hepatitis C virus (HCV) RNA-dependent RNA polymerase (RdRp) revealed extensive interactions between the fingers and the thumb subdomains, resulting in a closed conformation with an established template channel that should specifically accept single-stranded templates. We made circularized RNA templates and found that they were efficiently used by the HCV RdRp to synthesize product RNAs that are significantly longer than the template, suggesting that RdRp could exist in an open conformation prior to template binding. RNA synthesis using circular RNA templates had properties similar to those previously documented for linear RNA, including a need for higher GTP concentration for initiation, usage of GTP analogs, sensitivity to salt, and involvement of active-site residues for product formation. Some products were resistant to challenge with the template competitor heparin, indicating that the elongation complexes remain bound to template and are competent for RNA synthesis. Other products were not elongated in the presence of heparin, indicating that the elongation complex was terminated. Lastly, recombinant RdRps from two other flaviviruses and from the Pseudomonas phage phi6 also could use circular RNA templates for RNA-dependent RNA synthesis, although the phi6 RdRp could only use circular RNAs made from the 3'-terminal sequence of the phi6 genome.
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Affiliation(s)
- C T Ranjith-Kumar
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128, USA.
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Gaffney KJ, Lindenberg AM, Larsson J, Sokolowski-Tinten K, Blome C, Synnergren O, Sheppard J, Caleman C, MacPhee AG, Weinstein D, Lowney DP, Allison T, Matthews T, Falcone RW, Cavalieri AL, Fritz DM, Lee SH, Bucksbaum PH, Reis DA, Rudati J, Macrander AT, Fuoss PH, Kao CC, Siddons DP, Pahl R, Moffat K, Als-Nielsen J, Duesterer S, Ischebeck R, Schlarb H, Schulte-Schrepping H, Schneider J, von der Linde D, Hignette O, Sette F, Chapman HN, Lee RW, Hansen TN, Wark JS, Bergh M, Huldt G, van der Spoel D, Timneanu N, Hajdu J, Akre RA, Bong E, Krejcik P, Arthur J, Brennan S, Luening K, Hastings JB. Observation of structural anisotropy and the onset of liquidlike motion during the nonthermal melting of InSb. Phys Rev Lett 2005; 95:125701. [PMID: 16197085 DOI: 10.1103/physrevlett.95.125701] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2005] [Indexed: 05/04/2023]
Abstract
The melting dynamics of laser excited InSb have been studied with femtosecond x-ray diffraction. These measurements observe the delayed onset of diffusive atomic motion, signaling the appearance of liquidlike dynamics. They also demonstrate that the root-mean-squared displacement in the [111] direction increases faster than in the [110] direction after the first 500 fs. This structural anisotropy indicates that the initially generated fluid differs significantly from the equilibrium liquid.
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Affiliation(s)
- K J Gaffney
- Stanford Synchrotron Radiation Laboratory/SLAC, Menlo Park, California 94025, USA
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24
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Lindenberg AM, Larsson J, Sokolowski-Tinten K, Gaffney KJ, Blome C, Synnergren O, Sheppard J, Caleman C, Macphee AG, Weinstein D, Lowney DP, Allison TK, Matthews T, Falcone RW, Cavalieri AL, Fritz DM, Lee SH, Bucksbaum PH, Reis DA, Rudati J, Fuoss PH, Kao CC, Siddons DP, Pahl R, Als-Nielsen J, Duesterer S, Ischebeck R, Schlarb H, Schulte-Schrepping H, Tschentscher T, Schneider J, von der Linde D, Hignette O, Sette F, Chapman HN, Lee RW, Hansen TN, Techert S, Wark JS, Bergh M, Huldt G, van der Spoel D, Timneanu N, Hajdu J, Akre RA, Bong E, Krejcik P, Arthur J, Brennan S, Luening K, Hastings JB. Atomic-Scale Visualization of Inertial Dynamics. Science 2005; 308:392-5. [PMID: 15831753 DOI: 10.1126/science.1107996] [Citation(s) in RCA: 292] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The motion of atoms on interatomic potential energy surfaces is fundamental to the dynamics of liquids and solids. An accelerator-based source of femtosecond x-ray pulses allowed us to follow directly atomic displacements on an optically modified energy landscape, leading eventually to the transition from crystalline solid to disordered liquid. We show that, to first order in time, the dynamics are inertial, and we place constraints on the shape and curvature of the transition-state potential energy surface. Our measurements point toward analogies between this nonequilibrium phase transition and the short-time dynamics intrinsic to equilibrium liquids.
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Affiliation(s)
- A M Lindenberg
- Stanford Synchrotron Radiation Laboratory/Stanford Linear Accelerator Center (SLAC), Menlo Park, CA 94025, USA
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25
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Cavalieri AL, Fritz DM, Lee SH, Bucksbaum PH, Reis DA, Rudati J, Mills DM, Fuoss PH, Stephenson GB, Kao CC, Siddons DP, Lowney DP, Macphee AG, Weinstein D, Falcone RW, Pahl R, Als-Nielsen J, Blome C, Düsterer S, Ischebeck R, Schlarb H, Schulte-Schrepping H, Tschentscher T, Schneider J, Hignette O, Sette F, Sokolowski-Tinten K, Chapman HN, Lee RW, Hansen TN, Synnergren O, Larsson J, Techert S, Sheppard J, Wark JS, Bergh M, Caleman C, Huldt G, van der Spoel D, Timneanu N, Hajdu J, Akre RA, Bong E, Emma P, Krejcik P, Arthur J, Brennan S, Gaffney KJ, Lindenberg AM, Luening K, Hastings JB. Clocking femtosecond X rays. Phys Rev Lett 2005; 94:114801. [PMID: 15903864 DOI: 10.1103/physrevlett.94.114801] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2004] [Indexed: 05/02/2023]
Abstract
Linear-accelerator-based sources will revolutionize ultrafast x-ray science due to their unprecedented brightness and short pulse duration. However, time-resolved studies at the resolution of the x-ray pulse duration are hampered by the inability to precisely synchronize an external laser to the accelerator. At the Sub-Picosecond Pulse Source at the Stanford Linear-Accelerator Center we solved this problem by measuring the arrival time of each high energy electron bunch with electro-optic sampling. This measurement indirectly determined the arrival time of each x-ray pulse relative to an external pump laser pulse with a time resolution of better than 60 fs rms.
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Affiliation(s)
- A L Cavalieri
- FOCUS Center, Departments of Physics and Applied Physics Program, University of Michigan, Ann Arbor, MI 48109, USA
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Cai YQ, Mao HK, Chow PC, Tse JS, Ma Y, Patchkovskii S, Shu JF, Struzhkin V, Hemley RJ, Ishii H, Chen CC, Jarrige I, Chen CT, Shieh SR, Huang EP, Kao CC. Ordering of hydrogen bonds in high-pressure low-temperature H2O. Phys Rev Lett 2005; 94:025502. [PMID: 15698189 DOI: 10.1103/physrevlett.94.025502] [Citation(s) in RCA: 34] [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: 08/11/2004] [Indexed: 05/24/2023]
Abstract
The near K-edge structure of oxygen in liquid water and ices III, II, and IX at 0.25 GPa and several low temperatures down to 4 K has been studied using inelastic x-ray scattering at 9884.7 eV with a total energy resolution of 305 and 175 meV. A marked decrease of the preedge intensity from the liquid phase and ice III to ices II and IX is attributed to ordering of the hydrogen bonds in the proton-ordered lattice of the latter phases. Density functional theory calculations including the influence of the Madelung potential of the ice IX crystal correctly account for the remaining preedge feature. Furthermore, we obtain spectroscopic evidence suggesting a possible new phase of ice at temperatures between 4 and 50 K.
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Affiliation(s)
- Y Q Cai
- National Synchrotron Radiation Research Center, Hsinchu 30077, Taiwan
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27
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Ranjith-Kumar CT, Sarisky RT, Gutshall L, Thomson M, Kao CC. De novo initiation pocket mutations have multiple effects on hepatitis C virus RNA-dependent RNA polymerase activities. J Virol 2004; 78:12207-17. [PMID: 15507607 PMCID: PMC525054 DOI: 10.1128/jvi.78.22.12207-12217.2004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The hepatitis C virus (HCV) RNA-dependent RNA polymerase (RdRp) has several distinct biochemical activities, including initiation of RNA synthesis by a de novo mechanism, extension from a primed template, nontemplated nucleotide addition, and synthesis of a recombinant RNA product from two or more noncovalently linked templates (template switch). All of these activities require specific interaction with nucleoside triphosphates (NTPs). Based on the structure of the HCV RdRp bound to NTP (S. Bressanelli, L. Tomei, F. A. Rey, and R. DeFrancesco, J. Virol. 76:3482-3492, 2002), we mutated the amino acid residues that contact the putative initiation GTP and examined the effects on the various activities. Although all mutations retained the ability for primer extension, alanine substitution at R48, R158, R386, R394, or D225 decreased de novo initiation, and two or more mutations abolished de novo initiation. While the prototype enzyme had a K(m) for GTP of 3.5 microM, all of the mutations except one had K(m)s that were three- to sevenfold higher. These results demonstrate that the affected residues are functionally required to interact with the initiation nucleotide. Unexpectedly, many of the mutations also affected the addition of nontemplated nucleotide, indicating that residues in the initiating NTP (NTPi)-binding pocket are required for nontemplated nucleotide additions. Interestingly, mutations in D225 are dramatically affected in template switch, indicating that this residue of the NTPi pocket also interacts with components in the elongation complex. We also examined the interaction of ribavirin triphosphate with the NTPi-binding site.
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Affiliation(s)
- C T Ranjith-Kumar
- Department of Biochemistry and Biophysics, Texas A&M University, Mail Stop 2128, College Station, TX 77843, USA
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28
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Ablett JM, Berman LE, Kao CC, Rakowsky G, Lynch D. Small-gap insertion-device development at the National Synchrotron Light Source--performance of the new X13 mini-gap undulator. J Synchrotron Radiat 2004; 11:129-131. [PMID: 14960776 DOI: 10.1107/s0909049503022921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2003] [Accepted: 10/10/2003] [Indexed: 05/24/2023]
Abstract
The National Synchrotron Light Source (NSLS) 2.8 GeV electron storage ring continues to set high standards in insertion-device research and development. The Chasman-Green NSLS lattice design provides for dispersion-free long straight sections in addition to a very small vertical beta function. As the electron beam size is proportional to the square root of this function, a program to exploit this feature was undertaken more than a decade ago by implementing short-period small-gap insertion devices in the NSLS storage ring. The possibility of utilizing existing moderate-energy synchrotron radiation electron storage rings to produce high-brightness photon beams into the harder X-ray region have been realised using in-vacuum undulators. In this article the operation of a 1.25 cm-period mini-gap undulator, operating down to a gap of 3.3 mm within the NSLS X13 straight section, is reported. It is the brightest source of hard X-rays in the energy range approximately 3.7-16 keV at the NSLS, and replaces an in-vacuum undulator which had a more limited tunability.
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Affiliation(s)
- J M Ablett
- National Synchrotron Light Source, Brookhaven National Laboratory, Upton, NY 11973, USA.
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29
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Diamant R, Huotari S, Hämäläinen K, Sharon R, Kao CC, Deutsch M. Diagram X-ray emission spectra of a hollow atom: the Kh alpha1,2 and Kh beta1,3 hypersatellites of Fe. Phys Rev Lett 2003; 91:193001. [PMID: 14611577 DOI: 10.1103/physrevlett.91.193001] [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: 05/02/2003] [Indexed: 05/24/2023]
Abstract
High-resolution Fe K(h) beta(1,3) and K(h) alpha(1,2) hypersatellite spectra were measured, using monochromatized synchrotron radiation photoexcitation. The lines' energies, splitting, excitation thresholds, and the K(h) alpha(1)/K(h) alpha(2) intensity ratio were derived with high accuracy. Having both spectra, not hitherto available for any atom with high resolution, allows separating out the energy shifts of the outer levels caused by a K shell spectator vacancy. Comparison with ab initio relativistic multiconfigurational Dirac-Fock calculations reveals that while the influence of relativity and QED effects is mostly accounted for, discrepancies remain in the lines' intensity ratio, which sensitively measures the intermediacy of the coupling. Similar discrepancies, of unknown origin, are found in the energy shifts of the outer levels due to the final-state K shell spectator vacancy.
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Affiliation(s)
- R Diamant
- Physics Department, Bar-Ilan University, Ramat-Gan 52900, Israel
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30
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Zhong Z, Kao CC, Siddons DP, Zhong H, Hastings JB. A lamellar model for the X-ray rocking curves of sagittally bent Laue crystals. Acta Crystallogr A 2003; 59:1-6. [PMID: 12496454 DOI: 10.1107/s0108767302016835] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2002] [Accepted: 09/16/2002] [Indexed: 11/10/2022] Open
Abstract
The use of sagittally bent asymmetric Laue crystals in horizontally focusing monochromators for high-energy synchrotron X-rays necessitates simulation of the X-ray reflectivity by such crystals. Based on the theory of the lattice distortion in the diffraction plane of sagittally bent Laue crystals, a lamellar model was developed to predict their rocking curves. The model was experimentally verified by rocking-curve measurements from various reflections on silicon crystals of four representative orientations, sagittally bent to various radii, using X-rays of 67 keV energy.
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Affiliation(s)
- Z Zhong
- National Synchrotron Light Source, Brookhaven National Laboratory, Upton, NY 11973, USA.
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31
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Zhong Z, Kao CC, Siddons DP, Hastings JB. Rocking-curve width of sagittally bent Laue crystals. Acta Crystallogr A 2002; 58:487-93. [PMID: 12192122 DOI: 10.1107/s0108767302011261] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2001] [Accepted: 06/24/2002] [Indexed: 11/10/2022] Open
Abstract
The use of bent asymmetric Laue crystals to sagittally focus high-energy synchrotron X-rays calls for an understanding of the mechanisms affecting X-ray diffraction by such crystals. The rocking-curve width, a measurable quantity directly related to the distortion of the lattice planes, is the necessary first step towards such an understanding. A model is formulated for assessing the rocking-curve widths of sagittally bent Laue crystals, considering the elastic anisotropy. A method for depth-resolved measurement of the rocking curves was also developed to verify the model. The model successfully explains the wide range of rocking-curve widths of a large number of reflections from silicon crystals with two different orientations.
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Affiliation(s)
- Z Zhong
- National Synchrotron Light Source, Brookhaven National Laboratory, Upton, NY 11973, USA.
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32
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Menteş TO, Sánchez-Hanke C, Kao CC. Reconstruction of magnetization density in two-dimensional samples from soft X-ray speckle patterns using the multiple-wavelength anomalous diffraction method. J Synchrotron Radiat 2002; 9:90-95. [PMID: 11872929 DOI: 10.1107/s0909049502001310] [Citation(s) in RCA: 5] [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: 09/24/2001] [Accepted: 01/21/2002] [Indexed: 05/23/2023]
Abstract
A non-destructive technique for imaging magnetic domains in thin films and two-dimensional magnetic structures using coherent soft X-ray scattering and the multiple-wavelength anomalous diffraction method (MAD) is proposed. The method exploits the strong energy dependence in the magnetic scattering amplitude for 3d transition metals near the L(2,3) absorption edges and 4f elements near the M(4,5) absorption edges. The phase information required in the reconstruction algorithm is derived from the interference between the charge and magnetic scattering amplitudes. Magnetic speckle patterns from the magnetic domain distribution in an artificially defined Fe thin film are used to demonstrate this reconstruction algorithm. Circularly and linearly polarized incident light are examined separately to investigate the effect of polarization on the capability of the method.
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Affiliation(s)
- T O Menteş
- NSLS, Brookhaven National Laboratory, Upton, NY 11973, USA.
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33
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Ou LS, See LC, Wu CJ, Kao CC, Lin YL, Huang JL. Association between serum inflammatory cytokines and disease activity in juvenile idiopathic arthritis. Clin Rheumatol 2002; 21:52-6. [PMID: 11954886 DOI: 10.1007/s100670200012] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [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: 10/27/2022]
Abstract
Circulating interleukin-1beta (IL-1beta), IL-6, tumour necrosis factor-alpha (TNF-alpha), osteocalcin, and conventional parameters of inflammation were examined serially in 14 children with juvenile idiopathic arthritis (JIA) to determine any correlation with the disease activity. Serum IL-1beta was undetectable in all JIA patients. Serum IL-6, white blood cell counts, platelet counts, erythrocyte sedimentation rate and C-reactive protein levels were significantly elevated in the active phase of JIA, whereas hemoglobin levels were significantly lower. Osteocalcin levels were decreased and TNF-alpha increased in active JIA status, but these differences showed no statistical significance. We concluded that inflammatory cytokines play an important role in JIA. Monitoring IL-6 in children with JIA is useful in determining disease activity and response to therapy. These findings confirm earlier reports.
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Affiliation(s)
- L S Ou
- Department of Pediatrics, Chang Gung Children's Hospital and Chang Gung University, Taoyuan, Taiwan
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34
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Abstract
summary The core subgenomic promoter for the initiation of Cucumber mosaic virus (CMV) RNA4A was characterized in vitro using a template-dependent RNA synthesis assay and variants of the core promoter RNAs. The minimal sequence required for specific initiation from the cytidylate (T1) used in vivo consists of 31-nucleotides (nt) 3' of T1 and a 13 nt template sequence. This 44 nt RNA was found to provide three elements that contribute to efficient initiation of RNA4A synthesis by the CMV replicase: a stem-loop secondary structure 3' of T1, a template sequence that is rich in adenylates and uridylates, and T1 in an unbase-paired sequence.
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Affiliation(s)
- K Sivakumaran
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
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35
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Huang MC, Ho HO, Yeh GC, Ke WT, Lin LC, Hsu TM, Kao CC, Sheu MT. Development of a high-performance liquid chromatographic method for bioanalytical applications with sulpiride. J Chromatogr B Biomed Sci Appl 2001; 763:157-63. [PMID: 11710574 DOI: 10.1016/s0378-4347(01)00387-5] [Citation(s) in RCA: 25] [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] [Indexed: 10/27/2022]
Abstract
An improved HPLC method using a silica gel column with fluorescence detection (excitation at 300 nm and emission at 365 nm) was developed for the determination of sulpiride concentrations in plasma. Analysis of sulpiride in plasma samples was simplified by a one-step liquid-liquid extraction after alkaline treatment of only 1 ml of plasma. The low limit of quantitation was 20 ng/ml with a coefficient of variation of less than 20%. A linear range was found from 20 to 1500 ng/ml. This HPLC method was validated with the precision for inter-day and intra-day runs being 0.36-8.01% and 0.29-5.25%, respectively, and the accuracy (standard deviation of mean, SD) for inter-day and intra-day runs being -1.58 to 5.02% and -2.14 to 5.21%, respectively. Bioequivalence of the two products was evaluated in 12 normal healthy male volunteers in a single-dose, two-period, two-sequence, two-treatment cross-over study. Sulpiride plasma concentrations were analyzed with this validated HPLC method. Results demonstrated that the two tablet formulations of sulpiride appear to be bioequivalent.
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Affiliation(s)
- M C Huang
- Graduate Institute of Pharmaceutical Sciences, Taipei Medical University, Taiwan, ROC
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36
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Kim CH, Kao CC. A mutant viral RNA promoter with an altered conformation retains efficient recognition by a viral RNA replicase through a solution-exposed adenine. RNA 2001; 7:1476-1485. [PMID: 11680852 PMCID: PMC1370191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Brome mosaic virus (BMV) genomic minus-strand RNA synthesis requires an RNA motif named stem-loop C (SLC). An NMR-derived solution structure of SLC was reported by Kim et al. (Nature Struc Biol, 2000, 7:415-423) to contain three replicase-recognition elements, the most important of which is a stable stem with a terminal trinucleotide loop, 5'AUA3'. The 5'-most adenine of the triloop is rigidly fixed to the stem helix by interactions that require the 3'-most adenine, which is called a clamped adenine motif. However, a change of the 3' adenine to guanine (5'AUG3') unexpectedly directed RNA synthesis at 130% of wild type (Kim et al., Nature Struc Biol, 2000, 7:415-423). To understand how RNA with the AUG mutation maintains interaction with the BMV replicase, we used NMR and other biophysical techniques to elucidate the solution conformation of a 13-nt RNA containing the AUG triloop, called S-AUG. We found that S-AUG has a drastically different loop conformation in comparison to the wild type, as evidenced by an unusual C x G loop-closing base pair. Despite the conformational change, S-AUG maintains a solution-exposed adenine similar to the clamped adenine motif found in the wild type. Biochemical studies of the 5'AUG3' loop with various substitutions in the context of the whole SLC construct confirm that the clamped adenine motif exists in S-AUG remains a primary structural feature required for RNA synthesis by the BMV replicase.
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Affiliation(s)
- C H Kim
- Department of Chemistry, University of California, Berkeley, 94720-1460, USA
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37
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Ranjith-Kumar CT, Gajewski J, Gutshall L, Maley D, Sarisky RT, Kao CC. Terminal nucleotidyl transferase activity of recombinant Flaviviridae RNA-dependent RNA polymerases: implication for viral RNA synthesis. J Virol 2001; 75:8615-23. [PMID: 11507207 PMCID: PMC115107 DOI: 10.1128/jvi.75.18.8615-8623.2001] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recombinant hepatitis C virus (HCV) RNA-dependent RNA polymerase (RdRp) was reported to possess terminal transferase (TNTase) activity, the ability to add nontemplated nucleotides to the 3' end of viral RNAs. However, this TNTase was later purported to be a cellular enzyme copurifying with the HCV RdRp. In this report, we present evidence that TNTase activity is an inherent function of HCV and bovine viral diarrhea virus RdRps highly purified from both prokaryotic and eukaryotic cells. A change of the highly conserved GDD catalytic motif in the HCV RdRp to GAA abolished both RNA synthesis and TNTase activity. Furthermore, the nucleotides added via this TNTase activity are strongly influenced by the sequence near the 3' terminus of the viral template RNA, perhaps accounting for the previous discrepant observations between RdRp preparations. Last, the RdRp TNTase activity was shown to restore the ability to direct initiation of RNA synthesis in vitro on an initiation-defective RNA substrate, thereby implicating this activity in maintaining the integrity of the viral genome termini.
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Affiliation(s)
- C T Ranjith-Kumar
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA
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38
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Abstract
How the 5'-terminus of the template affects RNA synthesis by viral RNA replicases is poorly understood. Using short DNA, RNA and RNA-DNA chimeric templates that can direct synthesis of replicase products, we found that DNA templates tend to direct the synthesis of RNA products that are shorter by 1 nt in comparison to RNA templates. Template-length RNA synthesis was also affected by the concentration of nucleoside triphosphates, the identity of the bases at specific positions close to the 5'-terminus and the C2'-hydroxyl of a ribose at the third nucleotide from the 5'-terminal nucleotide. Similar requirements are observed with two bromoviral replicases, but not with a recombinant RNA-dependent RNA polymerase. These results begin to define the interactions needed for the viral replicase to complete synthesis of viral RNA.
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Affiliation(s)
- R Tayon
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
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39
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Abstract
RNA viruses use several initiation strategies to ensure that their RNAs are synthesized in appropriate amounts, have correct termini, and can be translated efficiently. Many viruses with genomes of single-stranded positive-, negative-, and double-stranded RNA initiate RNA synthesis by a de novo (primer-independent) mechanism. This review summarizes biochemical features and variations of de novo initiation in viral RNA replication.
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Affiliation(s)
- C C Kao
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA.
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40
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Kao CC, See LC, Yan DC, Ou LS, Huang JL. Time trends and seasonal variations in hospital admissions for childhood asthma in Taiwan from 1990 to 1998. Asian Pac J Allergy Immunol 2001; 19:63-8. [PMID: 11699722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
The aim of the study was to determine the trends and seasonal variations in hospital admissions for childhood asthma in a tertiary medical center since 1990. Data were collected according to the age and sex of patients and obtained from hospital registries between 1990 and 1998. Children between 2 and 14 years of age admitted with the diagnosis of asthma, or asthmatic bronchitis (ICD-9 code 493) were included. Age-specific and sex-specific hospital admission rates for asthma were calculated for each calendar year. The asthma admission rates were defined as the number of asthma admissions divided by the total number of all pediatric admissions in a year. Seasonal admission rates were calculated in a similar fashion. In addition, the number of readmissions was also calculated during the study period with comparisons of sex and age differences. The asthma admission rates showed a significant upward trend throughout the period studied, particularly among the 2-4 years of age group (relative risk = 2.08; p = 0.0001). Seasonal admission rates revealed a statistically significant increase during the October-December period, peaking in November or December of each calendar year (relative risk = 1.84; p = 0.0001). There was a male predominance in both age categories during the 9-year period. Comparisons of readmissions for asthma (at least three admissions) disclosed that girls were far more likely to be readmitted than boys among the 5-14 years of age group (p = 0.01). Our results indicate 1) an increased prevalence and severity of childhood asthma in Taiwan; 2) boys and younger children aged 2-4 years with asthma had increased risks of admission for asthma (relative risks were 1.22 and 1.96, respectively) and 3) girls among the older children with asthma tend to present with greater severity than boys owing to higher relative risks of readmission for asthma.
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Affiliation(s)
- C C Kao
- Department of Pediatrics, Chang Gung Children's Hospital and Chang Gung University, Taoyuan, Taiwan
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41
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Dräger G, Kirchner T, Bocharov S, Kao CC. Spin-resolved NEXAFS from resonant X-ray scattering (RXS). J Synchrotron Radiat 2001; 8:398-400. [PMID: 11512793 DOI: 10.1107/s0909049500017234] [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: 07/31/2000] [Accepted: 11/13/2000] [Indexed: 05/23/2023]
Abstract
Resonantly excited metal K core line spectra of NiO, MnO, CoO and other compounds have been investigated at the beamlines X21 (NSLS/BNL), BW1 and W1.1 (HASYLAB/DESY). From analysis of spectral data we have drawn the following conclusions: -spin conservation is valid in the scattering process, for excitations below the absorption threshold as well as above it, -the absorption thresholds are different for spin-up and spin-down components of resonantly scattered spectra, -quadrupole transitions are very important or even crucial in the excitation process. Provided that these conclusions are true, a novel technique for quantitative resolution of NEXAFS spectra into spin-up and spin-down components has been developed. Since the method employs spin conservation and local spin references, it needs no circularly polarized radiation and no sample magnetization for taking both the RXS and NEXAFS spectra. Hence antiferromagnetic and paramagnetic materials can be investigated as well. Utilizing linear dichroism by angular-dependent measurements on single-crystal samples additional resolution of NEXAFS spectra is possible with respect to the orbital symmetry. Application of the method to paramagnetic MnO, for the first time, provides new and unambiguous experimental results confirming modern (LSDA+U) calculations: The metal K pre-edge XAS of MnO has predominantly 3d(t2g and eg) spin-down character. On the other hand, the delocalized p-like states, arising from the p-d band effect hybridization have spin-up character.
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Affiliation(s)
- G Dräger
- Fachbereich Physik, Martin-Luther-Universitaet Halle-Wittenberg, Germany.
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42
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Jaing TH, Hsueh C, Tain YL, Hung IJ, Hsia SH, Kao CC. Tumor lysis syndrome in an infant with Langerhans cell histiocytosis successfully treated using continuous arteriovenous hemofiltration. J Pediatr Hematol Oncol 2001; 23:142-4. [PMID: 11216709 DOI: 10.1097/00043426-200102000-00016] [Citation(s) in RCA: 11] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Langerhans cell histiocytosis (LCH) is an enigmatic disease usually occurring in children. Tumor lysis syndrome (TLS) is a clinical syndrome associated with severe metabolic derangement and oliguric acute renal failure. In this report, we present the clinical course of an infant with advanced LCH who had TLS develop after chemotherapy. Treatment with continuous arteriovenous hemofiltration resulted in effective control of serum uric acid, potassium, creatinine, phosphorus, and blood urea nitrogen levels in the blood.
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Affiliation(s)
- T H Jaing
- Department of Medicine, Chang Gung Children's Hospital, Taoyuan, Taiwan.
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Abstract
The RNA-dependent RNA polymerase (RdRp) from hepatitis C virus (HCV), nonstructural protein 5B (NS5B), has recently been shown to direct de novo initiation using a number of complex RNA templates. In this study, we analyzed the features in simple RNA templates that are required to direct de novo initiation of RNA synthesis by HCV NS5B. NS5B was found to protect RNA fragments of 8 to 10 nucleotides (nt) from RNase digestion. However, NS5B could not direct RNA synthesis unless the template contained a stable secondary structure and a single-stranded sequence that contained at least one 3' cytidylate. The structure of a 25-nt template, named SLD3, was determined by nuclear magnetic resonance spectroscopy to contain an 8-bp stem and a 6-nt single-stranded sequence. Systematic analysis of changes in SLD3 revealed which features in the stem, loop, and 3' single-stranded sequence were required for efficient RNA synthesis. Also, chimeric molecules composed of DNA and RNA demonstrated that a DNA molecule containing a 3'-terminal ribocytidylate was able to direct RNA synthesis as efficiently as a sequence composed entirely of RNA. These results define the template sequence and structure sufficient to direct the de novo initiation of RNA synthesis by HCV RdRp.
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Affiliation(s)
- C C Kao
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA
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44
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Chen MH, Roossinck MJ, Kao CC. Efficient and specific initiation of subgenomic RNA synthesis by cucumber mosaic virus replicase in vitro requires an upstream RNA stem-loop. J Virol 2000; 74:11201-9. [PMID: 11070017 PMCID: PMC113212 DOI: 10.1128/jvi.74.23.11201-11209.2000] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [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: 11/20/2022] Open
Abstract
We defined the minimal core promoter sequences responsible for efficient and accurate initiation of cucumber mosaic virus (CMV) subgenomic RNA4. The necessary sequence maps to positions -28 to +15 relative to the initiation cytidylate used to initiate RNA synthesis in vivo. Positions -28 to -5 contain a 9-bp stem and a 6-nucleotide purine-rich loop. Considerable changes in the stem and the loop are tolerated for RNA synthesis, including replacement with a different stem-loop. In a template competition assay, the stem-loop and the initiation cytidylate are sufficient to interact with the CMV replicase. Thus, the mechanism of core promoter recognition by the CMV replicase appears to be less specific in comparison to the minimal subgenomic core promoter of the closely related brome mosaic virus.
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Affiliation(s)
- M H Chen
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA
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45
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Sivakumaran K, Kao CC. Genomic plus-strand RNA synthesis by the brome mosaic virus (BMV) RNA replicase requires a sequence that is complementary to the binding site of the BMV helicase-like protein. Mol Plant Pathol 2000; 1:337-346. [PMID: 20572981 DOI: 10.1046/j.1364-3703.2000.00037.x] [Citation(s) in RCA: 5] [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] [Indexed: 05/29/2023]
Abstract
Summary Initiation of genomic plus-strand RNA synthesis by the brome mosaic virus (BMV) replicase in vitro requires a 26-nucleotide (nt) RNA sequence at the 3' end of the minus-strand RNA and a nontemplated nucleotide 3' of the initiation cytidylate [Sivakumaran, K. and Kao, C.C. (1999)J. Virol.64, 6415-6423]. At the 5' end of this RNA is a 9-nt sequence called the cB box, the complement of the previously defined B box. The cB box can not be functionally replaced by the B box and has specific positional and sequence requirements. The portion of the cB box that is required for RNA synthesis in vitro is well-conserved in species in the Bromoviridae family. An equivalent RNA from Cucumber mosaic virus was unable to direct efficient RNA synthesis by the BMV replicase until the cB box was positioned at the same site relative to the BMV RNA and guanylates were present at positions +6 and +7 from the initiation cytidylate. These results further define the elements required for the recognition and initiation of viral genomic plus-strand RNA synthesis and suggest that a sequence important for minus-strand RNA synthesis is also required for plus-strand RNA synthesis.
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Affiliation(s)
- K Sivakumaran
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
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46
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Kim MJ, Zhong W, Hong Z, Kao CC. Template nucleotide moieties required for de novo initiation of RNA synthesis by a recombinant viral RNA-dependent RNA polymerase. J Virol 2000; 74:10312-22. [PMID: 11044075 PMCID: PMC110905 DOI: 10.1128/jvi.74.22.10312-10322.2000] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The recombinant RNA-dependent RNA polymerase of the bovine viral diarrhea virus specifically requires a cytidylate at the 3' end for the de novo initiation of RNA synthesis (C. C. Kao, A. M. Del Vecchio, and W. Zhong, Virology 253:1-7, 1999). Using RNAs containing nucleotide analogs, we found that the N3 and C4-amino group at the initiation cytidine were required for RNA synthesis. However, the ribose C2'-hydroxyl of the initiating cytidylate can accept several modifications and retain the ability to direct synthesis. The only unacceptable modification is a protonated C2'-amino group. Quite strikingly, the recognition of the functional groups for the initiation cytidylate and other template nucleotides are different. For example, a C5-methyl group in cytidine can direct RNA synthesis at all template positions except at the initiation cytidylate and C2'-amino modifications are tolerated better after the +11 position. When a 4-thiouracil (4sU) base analog that allows only imperfect base pairing with the nascent RNA is placed at different positions in the template, the efficiency of synthesis is correlated with the calculated stability of the template-nascent RNA duplex adjacent to the position of the 4sU. These results define the requirements for the specific interactions required for the initiation of RNA synthesis and will be compared to the mechanisms of initiation by other RNA-dependent and DNA-dependent RNA polymerases.
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Affiliation(s)
- M J Kim
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA
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47
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Sivakumaran K, Bao Y, Roossinck MJ, Kao CC. Recognition of the core RNA promoter for minus-strand RNA synthesis by the replicases of Brome mosaic virus and Cucumber mosaic virus. J Virol 2000; 74:10323-31. [PMID: 11044076 PMCID: PMC110906 DOI: 10.1128/jvi.74.22.10323-10331.2000] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [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: 07/07/2000] [Accepted: 08/21/2000] [Indexed: 11/20/2022] Open
Abstract
Replication of viral RNA genomes requires the specific interaction between the replicase and the RNA template. Members of the Bromovirus and Cucumovirus genera have a tRNA-like structure at the 3' end of their genomic RNAs that interacts with the replicase and is required for minus-strand synthesis. In Brome mosaic virus (BMV), a stem-loop structure named C (SLC) is present within the tRNA-like region and is required for replicase binding and initiation of RNA synthesis in vitro. We have prepared an enriched replicase fraction from tobacco plants infected with the Fny isolate of Cucumber mosaic virus (Fny-CMV) that will direct synthesis from exogenously added templates. Using this replicase, we demonstrate that the SLC-like structure in Fny-CMV plays a role similar to that of BMV SLC in interacting with the CMV replicase. While the majority of CMV isolates have SLC-like elements similar to that of Fny-CMV, a second group displays sequence or structural features that are distinct but nonetheless recognized by Fny-CMV replicase for RNA synthesis. Both motifs have a 5'CA3' dinucleotide that is invariant in the CMV isolates examined, and mutational analysis indicates that these are critical for interaction with the replicase. In the context of the entire tRNA-like element, both CMV SLC-like motifs are recognized by the BMV replicase. However, neither motif can direct synthesis by the BMV replicase in the absence of other tRNA-like elements, indicating that other features of the CMV tRNA can induce promoter recognition by a heterologous replicase.
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Affiliation(s)
- K Sivakumaran
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA
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48
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Abstract
We developed a convenient colorimetric assay for monitoring RNA synthesis from DNA-dependent RNA polymerases (DdRp) and viral RNA-dependent RNA polymerases (RdRp). ATP and GTP with a p-nitrophenyl moiety attached to the gamma-phosphate were synthesized (PNP-NTPs). These PNP-NTPs can be used for RNA synthesis by several RNA polymerases, including the RdRps from brome mosaic virus and bovine viral diarrhea virus and the DdRps from bacteriophage T7 and SP6. When the polymerase reactions were performed in the presence of alkaline phosphatase, which digests the p-nitrophenylpyrophosphate side-product of phosphoryl transfer to the chromogenic p-nitrophenylate, an increase in absorbence at 405 nm was observed. These nucleotide analogues were used in continuous colorimetric monitoring of polymerase activity. Furthermore, the PNP-NTPs were found to be stable and utilized by RNA polymerases in the presence of human plasma. This simple colorimetric polymerase assay can be performed in a standard laboratory spectrophotometer and will be useful in screens for inhibitors of viral RNA synthesis.
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Affiliation(s)
- W Vassiliou
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA
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49
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Tsai CL, Wang LH, Chang CF, Kao CC. Effects of gonadal steroids on brain serotonergic and aromatase activity during the critical period of sexual differentiation in tilapia, Oreochromis mossambicus. J Neuroendocrinol 2000; 12:894-8. [PMID: 10971814 DOI: 10.1046/j.1365-2826.2000.00536.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [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] [Indexed: 11/20/2022]
Abstract
The effects of gonadal steroids on brain serotonin (5-HT) and aromatase activity during the critical period of sexual differentiation were investigated in tilapia, Oreochromis mossambicus. Treatment of tilapia with 17beta-oestradiol (E2) between days 7 and 10 posthatching resulted in a significant increase in the female : male ratio as determined at day 90, and a significant reduction in brain 5-HT content. Treatment between days 10 and 20, or between days 20 and 30, had no significant effect. Since the 5-HT system may influence sexual differentiation, we examined the effects of para-chlorophenylalanine (p-CPA), a 5-HT synthesis inhibitor. As with E2, treatment of tilapia with p-CPA between days 7 and 10 posthatching resulted in a significant increase in the female : male ratio. Again, treatment between days 10 and 20, or between days 20 and 30, had no significant effect. Both p-CPA and E2 significantly depressed brain aromatase activity when administrated between days 7 and 10, but not subsequently. In tilapia treated between days 7 and 10, the brain 5-HT content was lowered by E2 to an extent similar to that seen with p-CPA, which is consistent with the suggestion that the effect of E2 on sexual differentiation may be mediated by the 5-HT system. Treatment of tilapia with 17alpha-methyltestosterone (MT), by contrast, resulted in a reduction in the female : male ratio, and treatment was most effective when given between days 10 and 20. The period of maximal effect of MT upon sex ratio appears to coincide with the ability of MT to induce an increase in brain aromatase activity.
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Affiliation(s)
- C L Tsai
- Department of Marine Resources, National Sun Yat-sen University, Kaohsiung, Taiwan, ROC.
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50
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Kao CC, Garner WL. Acute burns. Plast Reconstr Surg 2000; 105:2482-92; quiz 2493; discussion 2494. [PMID: 10845306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Burn injuries are complex cutaneous traumas cared for by many plastic surgeons. Care is stratified by burn size, depth, and associated injuries. Advances in surgical technique, wound care, and bioengineered skin have resulted in excellent outcomes for most burn survivors. Moderate burn injuries can be treated effectively by an interested and experienced plastic surgeon.
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Affiliation(s)
- C C Kao
- Division of Plastic and Reconstructive Surgery at the University of Southern California, Los Angeles 90033, USA
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