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Wu DS, Na SH, Li YJ, Zhou XB, Wu W, Song YT, Zheng P, Li Z, Luo JL. Single-crystal growth, structure and thermal transport properties of the metallic antiferromagnet Zintl-phase β-EuIn 2As 2. Phys Chem Chem Phys 2024; 26:8695-8703. [PMID: 37947451 DOI: 10.1039/d3cp04524b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Zintl-phase materials have attracted significant research interest owing to the interplay of magnetism and strong spin-orbit coupling, providing a prominent material platform for axion electrodynamics. Here, we report the single-crystal growth, structure, magnetic and electrical/thermal transport properties of the antiferromagnet layer Zintl-phase compound β-EuIn2As2. Importantly, the new layered structure of β-EuIn2As2, in rhombohedral (R3̄m) symmetry, contains triangular layers of Eu2+ ions. The in-plane resistivity ρ(H, T) measurements reveal metal behavior with an antiferromagnetic (AFM) transition (TN ∼ 23.5 K), which is consistent with the heat capacity Cp(H, T) and magnetic susceptibility χ(H, T) measurements. Negative MR was observed in the temperature range from 2 K to 20 K with a maximum MR ratio of 0.06. Unique 4f7J = S = 7/2 Eu2+ spins were supposed magnetically order along the c-axis. The Seebeck coefficient shows a maximum thermopower |Smax| of about 40 μV K-1. The kink around 23 K in the Seebeck coefficient originates from the effect of the antiferromagnetic phase on the electron band structure, while the pronounced thermal conductivity peak at around 10 K is attributed to the phonon-phonon Umklapp scattering. The results suggest that the Eu2+ spin arrangement plays an important role in the magnetic, electrical, and thermal transport properties in β-EuIn2As2, which might be helpful for future potential technical applications.
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Affiliation(s)
- D S Wu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - S H Na
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Y J Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - X B Zhou
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - W Wu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Y T Song
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - P Zheng
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Z Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - J L Luo
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
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Lei ZY, Ding BH, Wu QY, Luo JL, Li Z, Wang T, Wang YS, Chen YX, Huang LF, He JF, Yang XS, Guan TP, Ruan Q, Wang JH, Tang HS, Wang J, Cui SZ. [Efficacy of cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy for pseudomyxoma peritonei]. Zhonghua Wei Chang Wai Ke Za Zhi 2023; 26:1179-1186. [PMID: 38110280 DOI: 10.3760/cma.j.cn441530-20231018-00139] [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] [Grants] [Subscribe] [Scholar Register] [Indexed: 12/20/2023]
Abstract
Objective: To evaluate the efficacy and safety of cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) in the treatment of pseudomyxoma peritonei (PMP). Methods: In this descriptive case series study, we retrospective analyzed the records of PMP patients treated with CRS and HIPEC between January 2013 and June 2023 at Affiliated Cancer Hospital and Institute of Guangzhou Medical University. The inclusion criteria were as follows: (1) Aged 18 to 75 years and nonpregnant women. (2) Histologically confirmed diagnosis of pseudomyxoma peritonei. (3) Karnofsky Performance Scale (KPS)>70. (4) The functions of major organs such as the heart, liver, lungs, and kidneys can tolerate major surgery for long periods of time. (5) No evidence of extra-abdominal metastasis. Patients with extensive intra-abdominal adhesions or severe infectious diseases were excluded. The main outcomes were overall survival (OS) and postoperative major complications. The postoperative major complications were graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events (version 5.0). We used the peritoneal cancer index (PCI) score to quantitatively assess the peritoneal metastases and the completeness of cytoreduction (CCR) score at the end of surgery (CCR-0 and CCR-1 considered to be complete CRS). Results: A total of the 186 PMP patients with a median age of 56 (interquartile range extremes (IQRE), 48-64) years were included, 65 (34.9%) males and 121 (65.1%) females. The median peritoneal cancer index (PCI) score was 28 (20-34). Appendiceal origin accounted for 91.4%. Histological types were low grade in 99 patients (53.2%), high grade in 57 patients (30.6%), and 55 patients (29.6%) received complete cytoreduction (CCR-0/1). The median operative duration was 300 (211-430) minutes for all patients. Treatment-related 30-day mortality was 2.7%; 90-day mortality 4.3%; reoperation 1.6%; and severe morbidity 43.0%. Within the entire series, anemia(27.4%), electrolyte disturbance(11.6%), and hypoalbuminemia(7.5%) were the most frequent major complications (grade 3-4). The incidences of gastrointestinal anastomotic leakage, abdominal bleeding, and abdominal infection were 2.2%, 2.2%, and 4.3%, respectively. After a median follow-up of 38.1 (95%CI:31.2-45.1) months, the 5-year OS was 50.3% (95%CI: 40.7%-59.9%) with a median survival time of 66.1 (95%CI: 43.1-89.1) months. The survival analysis showed that patients with pathological low grade, low PCI, and low CCR score had better survival with statistically significant differences (all P<0.05). Further stratified into complete and incomplete CRS subgroups, the 5-year OS of the CCR-0 and CCR-1 subgroups was 88.9% (95%CI: 68.3%-100.0%) and 77.6% (95%CI: 62.7%-92.5%), respectively; and 42.0% (95%CI: 29.5%-54.5%) in the CCR-2/3 subgroup. Conclusions: CRS and HIPEC may result in a long-term survival benefit for PMP patients with acceptable perioperative morbidity and mortality. This strategy, when complete CRS is possible, could significantly prolong survival for strictly selected patients at experienced centers.
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Affiliation(s)
- Z Y Lei
- Department of Gastrointestinal Surgery, Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou 510095, China
| | - B H Ding
- Department of Gastrointestinal Surgery, Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou 510095, China
| | - Q Y Wu
- Department of Gastrointestinal Surgery, Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou 510095, China
| | - J L Luo
- Department of Gastrointestinal Surgery, Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou 510095, China
| | - Z Li
- Department of Gastrointestinal Surgery, Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou 510095, China
| | - T Wang
- Department of Gastrointestinal Surgery, Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou 510095, China
| | - Y S Wang
- Department of Gastrointestinal Surgery, Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou 510095, China
| | - Y X Chen
- Department of Gastrointestinal Surgery, Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou 510095, China
| | - L F Huang
- Department of Gastrointestinal Surgery, Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou 510095, China
| | - J F He
- Department of Gastrointestinal Surgery, Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou 510095, China
| | - X S Yang
- Department of Gastrointestinal Surgery, Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou 510095, China
| | - T P Guan
- Department of Gastrointestinal Surgery, Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou 510095, China
| | - Q Ruan
- Department of Gastrointestinal Surgery, Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou 510095, China
| | - J H Wang
- Department of Gastrointestinal Surgery, Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou 510095, China
| | - H S Tang
- Department of Gastrointestinal Surgery, Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou 510095, China
| | - J Wang
- Department of Gastrointestinal Surgery, Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou 510095, China
| | - S Z Cui
- Department of Gastrointestinal Surgery, Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou 510095, China
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Lei ZY, Guan TP, Luo JL, Tang HS, Cui SZ. [Rationality of performing hyperthermic intraperitoneal chemotherapy 5-8 weeks after primary tumor resection for patients with locally advanced colorectal cancer-based on COLOPEC]. Zhonghua Wei Chang Wai Ke Za Zhi 2020; 22:1115-1117. [PMID: 31874525 DOI: 10.3760/cma.j.issn.1671-0274.2019.12.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Hyperthermic intraperitoneal chemotherapy (HIPEC) has a unique effect on the prevention and treatment of peritoneal metastasis from malignancies. Recently, the first prospective, multicenter, randomized controlled clinical trial of HIPEC to prevent the development of peritoneal metastasis after curative surgery for patients with locally advanced colon cancer was published in the "Lancet Gastroenterol Hepatol" (COLOPEC). Regrettably, no significant difference was observed in 18-month peritoneal metastasis-free survival between postoperative adjuvant HIPEC and standard systemic chemotherapy for patients with T4 stage or perforated colon cancer. However, we wonder whether we might achieve better outcomes by further optimizing the following issues: (1) We propose that the inclusion criteria for that trial may not be entirely reasonable, which included pT4N0-2M0 and perforation. Additionally, we found that 91% of patients underwent HIPEC 5-8 weeks after primary tumor resection. (2) The imbalance in starting time of postoperative systemic chemotherapy between the two groups may have a negative impact.(3) Nine patients with peritoneal metastasis preceding HIPEC might weaken the potential efficacy of HIPEC. (4) We wonder whether HIPEC using high-dese oxaliplatin (460 mg/m(2)) perfusing 30 minutes for one cycle is the optimal regimen. Therefore, we are planning to conduct a randomized controlled trial (HIPEC-06) in accordcance with the characteristics of Chinese patients, to explore the clinical efficacy of curative surgery combined with HIPEC in the treatment of cT4 colorectal cancer.
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Affiliation(s)
- Z Y Lei
- Department of Abdominal Surgery, Affiliated Cancer Hospital & Institute, Guangzhou Medical University, Guangzhou 510095, China
| | - T P Guan
- Department of Abdominal Surgery, Affiliated Cancer Hospital & Institute, Guangzhou Medical University, Guangzhou 510095, China
| | - J L Luo
- Department of Oncology, Guangzhou Medical University, Guangzhou 510095, China
| | - H S Tang
- Department of Abdominal Surgery, Affiliated Cancer Hospital & Institute, Guangzhou Medical University, Guangzhou 510095, China
| | - S Z Cui
- Department of Abdominal Surgery, Affiliated Cancer Hospital & Institute, Guangzhou Medical University, Guangzhou 510095, China
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Ban WJ, Wu DS, Xu B, Luo JL, Xiao H. Revealing 'plasmaron' feature in DySb by optical spectroscopy study. J Phys Condens Matter 2019; 31:405701. [PMID: 31242466 DOI: 10.1088/1361-648x/ab2d1a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We report magnetic susceptibility, resistivity and optical spectroscopy study on single crystal sample DySb. It exhibits extremely large magnetoresistance (XMR), and a magnetic phase transition from paramagnetic (PM) to antiferromagnetic (AFM) state at about 10 K. A 'screened' plasma edge at about 4000 cm-1 is revealed by optical measurement, which suggests that the material has a low carrier density. With decreasing temperature, the 'screened' plasma edge shows a blue shift, possibly due to a decrease of the effective mass of carriers. Notably, an anomalous temperature dependent midinfrared absorption feature is observed in the vicinity of the 'screened' plasma edge. In addition, it can be connected to the inflection point in the real part of the dielectric function [Formula: see text], the frequency of which exactly tracks the temperature dependent 'screened' plasma frequency. This phenomena can be explained by the appearance of a coupled electron-plasmon 'plasmaron' feature.
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Affiliation(s)
- W J Ban
- Center for High Pressure Science and Technology Advanced Research, Beijing 100094, People's Republic of China
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Liu KL, Luo JL, Wu J, Wang YD, Fan HJ. A Preliminary Study of the Value of Plasma microRNA-193b and Soluble Urokinase-Type Plasminogen Activator Receptor in Identifying Patients with Early-Stage Colorectal Cancer and. Clin Lab 2019; 63:1949-1953. [PMID: 29226653 DOI: 10.7754/clin.lab.2017.170726] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND Early detection and management of colorectal cancer (CRC) and colorectal adenoma (CRA) reduces the mortality and morbidity of CRC, but there is a lack of ideal circulation biomarkers. METHODS A total of 80 patients with early-stage CRC and CRA and 30 healthy controls were included in this preliminary study. Plasma samples were collected before colonoscopy and prepared for measurement of microRNA193b and soluble uPAR. RESULTS Plasma level of miR-193b was decreased through the normal-adenoma-carcinoma sequence with no significant difference between patients with CRC and advanced CRA. The AUC of ROC curve evaluating the value of miR-193b in discriminating patients with early stage CRC or advanced CRA from patients with non-advanced CRA or normal control subjects was 0.849 (95% CI 0.773 - 0.923, p < 0.001). Significant alteration of plasma suPAR is only observed in CRC group (p < 0.001). CONCLUSIONS Plasma miR-193b may be a novel candidate biomarker for screening patients with early-stage CRC and advanced CRA.
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Li SY, Huang PT, Fang Y, Wu Y, Zhou L, Luo JL, Wang XC, Chen YC. Ultrasonic Cavitation Ameliorates Antitumor Efficacy of Residual Cancer After Incomplete Radiofrequency Ablation in Rabbit VX2 Liver Tumor Model. Transl Oncol 2019; 12:1113-1121. [PMID: 31176089 PMCID: PMC6556620 DOI: 10.1016/j.tranon.2019.05.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 05/08/2019] [Indexed: 02/07/2023] Open
Abstract
Residual cancer after incomplete ablation remains a major problem for radiofrequency ablation (RFA). We aimed to investigate the synergetic treatment efficacy of RFA combined with ultrasonic cavitation for liver tumor. Sixty rabbits with VX2 liver tumor were randomly divided into three groups. Group A was control group without any treatment. Combined ultrasonic cavitation with RFA was performed for group B1. Group B2 underwent RFA alone. The histopathological results were compared at the 5th, 11th, and 18th day of experiment, and the survival time and metastasis were assessed. The tumor volume growth rate, percentage of necrosis area, microvessel density, and apoptosis index showed significant differences among these groups at the 5th day, 11th day, and 18th day of experiment (P < .05). In contrast, the difference of metastatic score was not significant at the 5th and 11th day (P > .05). At the 18th day, the metastatic score of group A was significant higher than that of group B1 (P < .05), whereas the differences between group A and group B2, or group B1 and group B2 were not significant (P > .05). The median/range interquartile of survival time in groups A, B1, and B2 were 25/8 days, 50/19 days, and 48/20 days, respectively, and there was significant difference between groups A and B1 or B2 (P < .05). The difference between groups B1 and B2 was not significant (P > .05). Ultrasonic cavitation after incomplete RFA for liver tumor improved the antitumor effect, which could be considered as a potentially useful combined therapeutic strategy for liver malignancy.
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Affiliation(s)
- Shi-Yan Li
- Department of Ultrasound, Sir Run Run Shaw Hospital, Zhejiang University, School of Medicine, Hangzhou, Zhejiang Province, China
| | - Pin-Tong Huang
- Department of Ultrasound, The Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, Zhejiang Province, China.
| | - Yong Fang
- Department of Oncology, Sir Run Run Shaw Hospital, Zhejiang University, School of Medicine, Hangzhou, Zhejiang Province, China
| | - Yao Wu
- Department of Ultrasound, Sir Run Run Shaw Hospital, Zhejiang University, School of Medicine, Hangzhou, Zhejiang Province, China
| | - Ling Zhou
- Department of Ultrasound, Sir Run Run Shaw Hospital, Zhejiang University, School of Medicine, Hangzhou, Zhejiang Province, China
| | - Jie-Li Luo
- Department of Ultrasound, The Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, Zhejiang Province, China
| | - Xian-Chen Wang
- Department of Ultrasound, Sir Run Run Shaw Hospital, Zhejiang University, School of Medicine, Hangzhou, Zhejiang Province, China
| | - Yun-Chong Chen
- Department of Ultrasound, Sir Run Run Shaw Hospital, Zhejiang University, School of Medicine, Hangzhou, Zhejiang Province, China
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Wang YH, Zhang GH, Zhang LL, Luo JL, Gao L, Zhao MS. [Clinical characteristic of 74 cases of malignant tumor in rheumatoid arthritis]. Beijing Da Xue Xue Bao Yi Xue Ban 2018; 50:986-990. [PMID: 30562769] [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: 06/09/2023]
Abstract
OBJECTIVE To investigate the clinical characteristics of rheumatoid arthritis (RA) patients with malignant tumor. METHODS Retrospective summary was made of 1 562 in patients of RA from January 2011 to June 2017. In the study, 74 RA patients with malignant tumor were reviewed and analyzed, and the general conditions, tumor types, RA and tumor onset sequence, and the medication situation were analyzed. RESULTS The incidence of malignant tumor in the patients with rheumatoid arthritis in our center was 4.16%. The 74 patients were complicated with malignant tumor, of whom 53 were female, and 21 male. The age of RA at presentation was (52.6±17.8) years. The average disease duration of malignant tumor was (63.4 ± 12.7) years. The onset time of rheumatoid arthritis was earlier than that of malignant tumors in 51 cases (51/74), with an average of (17.2±14.2) years between 2 and 60 years. The incidence of malignant tumor was earlier than that of rheumatoid arthritis in 16 cases (16/74), with an average of (6.2±5.9) years between 1 and 21 years, of which 10 cases were sex hormone related tumors. Seven cases (7/74) were diagnosed with RA at the same time, and the time interval between the two diseases was within 1 year. All the patients were over 60 years old with digestive tract tumors. All the 7 patients showed polyarthritis, significantly increased erythrocyte sedimentation rate and C-reactive protein, including 4 rheumatoid factor positive cases and 2 anti-CCP antibody positive cases. The effect of non-steroidal anti-inflammatory drugs and traditional drugs to improve the condition of the disease was poor in the 7 patients, and the condition was relieved after using low-dose glucocorticoids. Gastrointestinal tumors, breast and reproductive system tumors were the most common, followed by respiratory, urological and blood system tumors. CONCLUSION The risk in patients of rheumatoid arthritis complicated with malignant tumor is higher than that of the general population. A variety of factors play an important role in cancer risk of RA, including disease activity, some estrogen metabolites, the use of drugs and so on. Therefore, all RA patients should be screened for malignant tumor during diagnosis, and malignant tumor surveillance is mandatory for all rheumatoid arthritis patients after diagnosis.
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Affiliation(s)
- Y H Wang
- Department of Rheumatology and Immunology, Beijing Shijitan Hospital, Capital Medical University, Beijing 100038, China
| | - G H Zhang
- Department of Rheumatology and Immunology, Beijing Shijitan Hospital, Capital Medical University, Beijing 100038, China
| | - L L Zhang
- Department of Rheumatology and Immunology, Beijing Shijitan Hospital, Capital Medical University, Beijing 100038, China
| | - J L Luo
- Department of Rheumatology and Immunology, Beijing Shijitan Hospital, Capital Medical University, Beijing 100038, China
| | - L Gao
- Department of Rheumatology and Immunology, Beijing Shijitan Hospital, Capital Medical University, Beijing 100038, China
| | - M S Zhao
- Department of Rheumatology and Immunology, Beijing Shijitan Hospital, Capital Medical University, Beijing 100038, China
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Sun JP, Jiao YY, Yang CL, Wu W, Yi CJ, Wang BS, Shi YG, Luo JL, Uwatoko Y, Cheng JG. Effect of hydrostatic pressure on the superconducting properties of quasi-1D superconductor K 2Cr 3As 3. J Phys Condens Matter 2017; 29:455603. [PMID: 29049031 DOI: 10.1088/1361-648x/aa8c94] [Citation(s) in RCA: 2] [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] [Indexed: 06/07/2023]
Abstract
K2Cr3As3 is a newly discovered quasi-1D superconductor with a T c = 6.1 K and an upper critical field µ 0 H c2(0) ≈ 40 T three times larger than the Pauli paramagnetic limit µ 0 H p that is suggestive of a spin-triplet Cooper pairing. In this paper, we have investigated the effects of hydrostatic pressure on its T c and µ 0 H c2 by measuring the ac magnetic susceptibility χ'(T) under magnetic fields at various hydrostatic pressures up to 7.5 GPa. The major findings include: (1) T c is suppressed gradually to below 2 K at 7.5 GPa; (2) the estimated µ 0 H c2(0) decreases dramatically to below µ 0 H p above ~2 GPa and becomes slight lower than the orbital limiting field [Formula: see text] estimated from the initial slope of upper critical field via [Formula: see text] = -0.73T cdH c2/[Formula: see text] in the clean limit; (3) the estimated Maki parameter α = √2[Formula: see text]/H p drops from 4 at ambient pressure to well below 1 at P > 2 GPa, suggesting the crossover from Pauli paramagnetic limiting to orbital limiting in the pair breaking process upon increasing pressure. These observations suggested that the application of hydrostatic pressure could drive K2Cr3As3 away from the ferromagnetic instability and lead to a breakdown of the spin-triplet pairing channel. We have also made a side-by-side comparison and discussed the distinct effects of chemical and physical pressures on the superconducting properties of K2Cr3As3.
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Affiliation(s)
- J P Sun
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China. School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
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Zheng P, Xu YJ, Wu W, Xu G, Lv JL, Lin FK, Wang P, Yang YF, Luo JL. Orbital-dependent charge dynamics in MnP revealed by optical study. Sci Rep 2017; 7:14178. [PMID: 29079790 PMCID: PMC5660257 DOI: 10.1038/s41598-017-14648-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 10/12/2017] [Indexed: 11/24/2022] Open
Abstract
Unconventional superconductivity often emerges at the border of long-range magnetic orders. Understanding the low-energy charge dynamics may provide crucial information on the formation of superconductivity. Here we report the unpolarized/polarized optical conductivity study of high quality MnP single crystals at ambient pressure. Our data reveal two types of charge carriers with very different lifetimes. In combination with the first-principles calculations, we show that the short-lifetime carriers have flat Fermi sheets which become gapped in the helimagnetic phase, causing a dramatic change in the low-frequency optical spectra, while the long-lifetime carriers are anisotropic three-dimensional like which are little affected by the magnetic transitions and provide major contributions to the transport properties. This orbital-dependent charge dynamics originates from the special crystal structure of MnP and may have an influence on the unconventional superconductivity and its interplay with helimagnetism at high pressures.
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Affiliation(s)
- P Zheng
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
| | - Y J Xu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - W Wu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - G Xu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - J L Lv
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - F K Lin
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - P Wang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Yi-Feng Yang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China. .,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China. .,Collaborative Innovation Center of Quantum Matter, Beijing, 100190, China.
| | - J L Luo
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China.,Collaborative Innovation Center of Quantum Matter, Beijing, 100190, China
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10
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Ban WJ, Luo JL, Wang NL. Revealing correlation effect of Co 3d electrons in La 3Co 4Sn 13 and Ce 3Co 4Sn 13 by infrared spectroscopy study. J Phys Condens Matter 2017; 29:405603. [PMID: 28695842 DOI: 10.1088/1361-648x/aa7ef8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We report resistivity, specific heat and optical spectroscopy measurements on single crystal samples of [Formula: see text] [Formula: see text] [Formula: see text] and [Formula: see text] [Formula: see text] [Formula: see text]. We observed clear temperature-induced spectral weight suppression below 4000 [Formula: see text] for both compounds in the conductivity spectra [Formula: see text], indicating the progressive formation of gap-like features with decreasing temperature. The suppressed spectral weight transfers mostly to the higher energy region. This observation reflects the presence of the correlation effect in the compounds. We attribute the correlation effect to the Co 3d electrons.
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Affiliation(s)
- W J Ban
- Institute of Physics, Chinese Academy of Sciences, Beijing, People's Republic of China
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11
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Wang Y, Feng Y, Cheng JG, Wu W, Luo JL, Rosenbaum TF. Spiral magnetic order and pressure-induced superconductivity in transition metal compounds. Nat Commun 2016; 7:13037. [PMID: 27708255 PMCID: PMC5059728 DOI: 10.1038/ncomms13037] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [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: 03/14/2016] [Accepted: 08/29/2016] [Indexed: 11/13/2022] Open
Abstract
Magnetic and superconducting ground states can compete, cooperate and coexist. MnP provides a compelling and potentially generalizable example of a material where superconductivity and magnetism may be intertwined. Using a synchrotron-based non-resonant X-ray magnetic diffraction technique, we reveal a spiral spin order in MnP and trace its pressure evolution towards superconducting order via measurements in a diamond anvil cell. Judging from the magnetostriction, ordered moments vanish at the quantum phase transition as pressure increases the electron kinetic energy. Spins remain local in the disordered phase, and the promotion of superconductivity is likely to emerge from an enhanced coupling to residual spiral spin fluctuations and their concomitant suppression of phonon-mediated superconductivity. As the pitch of the spiral order varies across the 3d transition metal compounds in the MnP family, the magnetic ground state switches between antiferromagnet and ferromagnet, providing an additional tuning parameter in probing spin-fluctuation-induced superconductivity. The relationship between magnetic order and superconductivity is one of the central issues in unconventional superconductors. Here, Wang et al. report a spiral spin order in MnP and trace its pressure evolution towards superconducting order, suggesting variable spiral pitch as a mechanism to tune spin-fluctuation-induced superconductivity.
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Affiliation(s)
- Yishu Wang
- Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, California 91125, USA
| | - Yejun Feng
- Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, California 91125, USA.,The Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - J-G Cheng
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - W Wu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - J L Luo
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.,Collaborative Innovation Center of Quantum Matter, Beijing 100190, China
| | - T F Rosenbaum
- Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, California 91125, USA
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12
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Luo JL, Zhao XM. [The significance and application of serum eosinophil cationic proteinand IgG4 antibody in patients with allergic rhinitistreated by allergic specific immunotherapy]. Lin Chung Er Bi Yan Hou Tou Jing Wai Ke Za Zhi 2016; 30:1047-1048. [PMID: 29798035 DOI: 10.13201/j.issn.1001-1781.2016.13.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Indexed: 11/12/2022]
Abstract
Objective:To study the significance and application of serum eosinophil cationic protein(ECP) and IgG4 antibody in patients with allergic rhinitis treated by allergic specific immunotherapy.Method:The level of IgG4 antibody and eosinophil cationic protein in serum was measured in 33 cases of allergic rhinitis before treatment and half a year and one year after treatment.The change of ECP level was observed in different age groups,and the relationship between serum IgG4 and ECP after treatment was analyzed.Result:IgG4 antibody in the serum significantly increased after treatment,and the difference was statistically significant(P<0.05).In the serum ECP content gradually reduced after treatment,and the difference was statistically significant(P<0.05).No obvious difference in ECP level was observed among dfferent age groups after treatment (P<0.05).The level of serum IgG4 was negatively correlated with serum ECP level despite statistical insignificance(r=-0.138,P>0.05).Conclusion:ECP is a sign of eosinophil activation,which is an important factor leading to the nasal inflammation.The content of serum ECP can be used as an indicator for patients with allergic rhinitis recieving nonspecific immune treatment .IgG4 antibody is a relatively reliable indicator to evaluate the treatment effect of specific immunotherapy,and may be negatively related to the serum ECP levels.
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Affiliation(s)
- J L Luo
- Department of Otorhinolaryngology,Zhuhai People's Hospital,Jinan University,Zhuhai,519000,China
| | - X M Zhao
- Department of Otorhinolaryngology,Zhuhai People's Hospital,Jinan University,Zhuhai,519000,China
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13
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Busacca S, Law EWP, Powley IR, Proia DA, Sequeira M, Le Quesne J, Klabatsa A, Edwards JM, Matchett KB, Luo JL, Pringle JH, El-Tanani M, MacFarlane M, Fennell DA. Resistance to HSP90 inhibition involving loss of MCL1 addiction. Oncogene 2015; 35:1483-92. [PMID: 26096930 PMCID: PMC4819782 DOI: 10.1038/onc.2015.213] [Citation(s) in RCA: 25] [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: 10/29/2014] [Revised: 03/02/2015] [Accepted: 03/14/2015] [Indexed: 12/21/2022]
Abstract
Inhibition of the chaperone heat-shock protein 90 (HSP90) induces apoptosis, and it is a promising anti-cancer strategy. The mechanisms underpinning apoptosis activation following HSP90 inhibition and how they are modified during acquired drug resistance are unknown. We show for the first time that, to induce apoptosis, HSP90 inhibition requires the cooperation of multi BH3-only proteins (BID, BIK, PUMA) and the reciprocal suppression of the pro-survival BCL-2 family member MCL1, which occurs via inhibition of STAT5A. A subset of tumour cell lines exhibit dependence on MCL1 expression for survival and this dependence is also associated with tumour response to HSP90 inhibition. In the acquired resistance setting, MCL1 suppression in response to HSP90 inhibitors is maintained; however, a switch in MCL1 dependence occurs. This can be exploited by the BH3 peptidomimetic ABT737, through non-BCL-2-dependent synthetic lethality.
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Affiliation(s)
- S Busacca
- Department of Cancer Studies, Cancer Research UK Leicester Centre, University of Leicester, Leicester, UK
| | - E W P Law
- Department of Cancer Studies, Cancer Research UK Leicester Centre, University of Leicester, Leicester, UK
| | | | - D A Proia
- Synta Pharmaceuticals Corp., Lexington, MA, USA
| | - M Sequeira
- Synta Pharmaceuticals Corp., Lexington, MA, USA
| | - J Le Quesne
- Department of Cancer Studies, Cancer Research UK Leicester Centre, University of Leicester, Leicester, UK.,MRC Toxicology Unit, Leicester, UK
| | - A Klabatsa
- Division of Cancer Studies, King's College London, London, UK
| | | | - K B Matchett
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, UK
| | - J L Luo
- Department of Cancer Studies, Cancer Research UK Leicester Centre, University of Leicester, Leicester, UK
| | - J H Pringle
- Department of Cancer Studies, Cancer Research UK Leicester Centre, University of Leicester, Leicester, UK
| | - M El-Tanani
- Institute of Cancer Therapeutics, School of Life Sciences, University of Bradford, Bradford, UK
| | | | - D A Fennell
- Department of Cancer Studies, Cancer Research UK Leicester Centre, University of Leicester, Leicester, UK
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14
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Cheng JG, Matsubayashi K, Wu W, Sun JP, Lin FK, Luo JL, Uwatoko Y. Pressure induced superconductivity on the border of magnetic order in MnP. Phys Rev Lett 2015; 114:117001. [PMID: 25839302 DOI: 10.1103/physrevlett.114.117001] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Indexed: 06/04/2023]
Abstract
We report the discovery of superconductivity on the border of long-range magnetic order in the itinerant-electron helimagnet MnP via the application of high pressure. Superconductivity with T(sc)≈1 K emerges and exists merely near the critical pressure P(c)≈8 GPa, where the long-range magnetic order just vanishes. The present finding makes MnP the first Mn-based superconductor. The close proximity of superconductivity to a magnetic instability suggests an unconventional pairing mechanism. Moreover, the detailed analysis of the normal-state transport properties evidenced non-Fermi-liquid behavior and the dramatic enhancement of the quasiparticle effective mass near P(c) associated with the magnetic quantum fluctuations.
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Affiliation(s)
- J-G Cheng
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - K Matsubayashi
- Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - W Wu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - J P Sun
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - F K Lin
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - J L Luo
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Collaborative Innovation Center of Quantum Matter, Beijing, China
| | - Y Uwatoko
- Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
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15
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Ge YQ, Luo JL, Li L, Jin XX, Tang DY, Shen DY, Zhang SM, Zhao LM. Initial conditions for dark soliton generation in normal-dispersion fiber lasers. Appl Opt 2015; 54:71-75. [PMID: 25967008 DOI: 10.1364/ao.54.000071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 11/17/2014] [Indexed: 06/04/2023]
Abstract
We report results of numerical simulations on the various initial conditions for dark soliton generation in an all-normal-dispersion fiber laser. All the dark solitons generated are odd dark solitons. Differently from the dark soliton generation in fibers, where an arbitrary dip could evolve into a dark soliton, it is found that the dark soliton can originate only from an initial dip with a certain parameter requirement. A bright pulse with either a hyperbolic secant square, Gaussian, or Lorentz profile can be developed into a dark soliton, provided that the parameters of the initial bright pulse are selected. Dark solitons can be generated in fiber lasers only if there is a phase jump, and this phase jump can be maintained and evolve to π during the pulse evolution.
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16
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Ding H, Nakayama K, Richard P, Souma S, Sato T, Takahashi T, Neupane M, Xu YM, Pan ZH, Fedorov AV, Wang Z, Dai X, Fang Z, Chen GF, Luo JL, Wang NL. Electronic structure of optimally doped pnictide Ba0.6K0.4Fe2As2: a comprehensive angle-resolved photoemission spectroscopy investigation. J Phys Condens Matter 2011; 23:135701. [PMID: 21415479 DOI: 10.1088/0953-8984/23/13/135701] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The electronic structure of the Fe-based superconductor Ba(0.6)K(0.4)Fe(2)As(2) is studied by means of angle-resolved photoemission. We identify dispersive bands crossing the Fermi level forming hole-like (electron-like) Fermi surfaces (FSs) around Γ (M) with nearly nested FS pockets connected by the antiferromagnetic wavevector. Compared to band structure calculation findings, the overall bandwidth is reduced by a factor of 2 and the low energy dispersions display even stronger mass renormalization. Using an effective tight banding model, we fitted the band structure and the FSs to obtain band parameters reliable for theoretical modeling and calculation of physical quantities.
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Affiliation(s)
- H Ding
- Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing, People's Republic of China.
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17
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Yuan HQ, Jiao L, Singleton J, Balakirev FF, Chen GF, Luo JL, Wang NL. The magnetoresistance and Hall effect in CeFeAsO: a high magnetic field study. ACTA ACUST UNITED AC 2011. [DOI: 10.1088/1742-6596/273/1/012110] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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18
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Nakayama K, Sato T, Richard P, Kawahara T, Sekiba Y, Qian T, Chen GF, Luo JL, Wang NL, Ding H, Takahashi T. Angle-resolved photoemission spectroscopy of the iron-chalcogenide superconductor Fe1.03Te0.7Se0.3: strong coupling behavior and the universality of interband scattering. Phys Rev Lett 2010; 105:197001. [PMID: 21231191 DOI: 10.1103/physrevlett.105.197001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2009] [Revised: 03/10/2010] [Indexed: 05/30/2023]
Abstract
We have performed angle-resolved photoemission spectroscopy of the iron-chalcogenide superconductor Fe1.03Te0.7Se0.3 to investigate the electronic structure relevant to superconductivity. We observed a holelike Fermi surface (FS) and an electronlike FS at the Brillouin zone center and corner, respectively, which are nearly nested by the Q∼(π,π) wave vector. We do not find evidence for the nesting instability with Q∼(π+δ,0) reminiscent of the antiferromagnetic order in the parent compound Fe1+yTe. We have observed an isotropic superconducting (SC) gap along the holelike FS with the gap size Δ of ∼4 meV (2Δ/kBTc ∼ 7), demonstrating the strong-coupling superconductivity. The observed similarity of low-energy electronic excitations between iron-chalcogenides and iron-arsenides strongly suggests that common interactions which involve Q∼(π,π) scattering are responsible for the SC pairing.
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Affiliation(s)
- K Nakayama
- Department of Physics, Tohoku University, Sendai 980-8578, Japan
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19
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Torchinsky DH, Chen GF, Luo JL, Wang NL, Gedik N. Band-dependent quasiparticle dynamics in single crystals of the Ba(0.6)K(0.4)Fe2As2 superconductor revealed by pump-probe spectroscopy. Phys Rev Lett 2010; 105:027005. [PMID: 20867732 DOI: 10.1103/physrevlett.105.027005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Revised: 02/15/2010] [Indexed: 05/29/2023]
Abstract
We report on band-dependent quasiparticle dynamics in Ba(0.6)K(0.4)Fe2As2 (Tc=37 K) measured using ultrafast pump-probe spectroscopy. In the superconducting state, we observe two distinct relaxation processes: a fast component whose decay rate increases linearly with excitation density and a slow component with an excitation density independent decay rate. We argue that these two components reflect the recombination of quasiparticles in the two hole bands through intraband and interband processes. We also find that the thermal recombination rate of quasiparticles increases quadratically with temperature. The temperature and excitation density dependence of the decays indicates fully gapped hole bands and nodal or very anisotropic electron bands.
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Affiliation(s)
- Darius H Torchinsky
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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20
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Richard P, Nakayama K, Sato T, Neupane M, Xu YM, Bowen JH, Chen GF, Luo JL, Wang NL, Dai X, Fang Z, Ding H, Takahashi T. Observation of Dirac cone electronic dispersion in BaFe2As2. Phys Rev Lett 2010; 104:137001. [PMID: 20481905 DOI: 10.1103/physrevlett.104.137001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Revised: 12/17/2009] [Indexed: 05/29/2023]
Abstract
We performed an angle-resolved photoemission spectroscopy study of BaFe2As2, which is the parent compound of the so-called 122 phase of the iron-pnictide high-temperature superconductors. We reveal the existence of a Dirac cone in the electronic structure of this material below the spin-density-wave temperature, which is responsible for small spots of high photoemission intensity at the Fermi level. Our analysis suggests that the cone is slightly anisotropic and its apex is located very near the Fermi level, leading to tiny Fermi surface pockets. The bands forming the cone show an anisotropic leading edge gap away from the cone that suggests a nodal spin-density-wave description.
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Affiliation(s)
- P Richard
- WPI Research Center, Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
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21
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Chia EEM, Talbayev D, Zhu JX, Yuan HQ, Park T, Thompson JD, Panagopoulos C, Chen GF, Luo JL, Wang NL, Taylor AJ. Ultrafast pump-probe study of phase separation and competing orders in the underdoped (Ba,K)Fe2As2 superconductor. Phys Rev Lett 2010; 104:027003. [PMID: 20366619 DOI: 10.1103/physrevlett.104.027003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2008] [Indexed: 05/29/2023]
Abstract
We report measurements of quasiparticle relaxation dynamics in the high-temperature superconductor (Ba,K)Fe2As2 in optimally doped, underdoped, and undoped regimes. In the underdoped sample, spin-density wave (SDW) order forms at approximately 85 K, followed by superconductivity at approximately 28 K. We find the emergence of a normal-state order that suppresses SDW at a temperature T{*} approximately 60 K and argue that this normal-state order is a precursor to superconductivity.
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Affiliation(s)
- Elbert E M Chia
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
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22
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Sato T, Nakayama K, Sekiba Y, Richard P, Xu YM, Souma S, Takahashi T, Chen GF, Luo JL, Wang NL, Ding H. Band structure and fermi surface of an extremely overdoped iron-based superconductor KFe2As2. Phys Rev Lett 2009; 103:047002. [PMID: 19659391 DOI: 10.1103/physrevlett.103.047002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2008] [Indexed: 05/28/2023]
Abstract
We have performed high-resolution angle-resolved photoemission spectroscopy on heavily overdoped KFe_{2}As_{2} (transition temperature T_{c} = 3 K). We observed several renormalized bands near the Fermi level with a renormalization factor of 2-4. While the Fermi surface around the Brillouin-zone center is qualitatively similar to that of optimally doped Ba_{1-x}K_{x}Fe_{2}As_{2} (x = 0.4; T_{c} = 37 K), the Fermi surface topology around the zone corner (M point) is markedly different: the two electron Fermi surface pockets are completely absent due to an excess of hole doping. This result indicates that the electronic states around the M point play an important role in the high-T_{c} superconductivity of Ba_{1-x}K_{x}Fe_{2}As_{2} and suggests that the interband scattering via the antiferromagnetic wave vector essentially controls the T_{c} value in the overdoped region.
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Affiliation(s)
- T Sato
- Department of Physics, Tohoku University, Sendai 980-8578, Japan and TRiP, Japan Science and Technology Agency (JST), Kawaguchi 332-0012, Japan
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23
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Xia Y, Qian D, Wray L, Hsieh D, Chen GF, Luo JL, Wang NL, Hasan MZ. Fermi surface topology and low-lying quasiparticle dynamics of parent Fe1+xTe/Se superconductor. Phys Rev Lett 2009; 103:037002. [PMID: 19659308 DOI: 10.1103/physrevlett.103.037002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2009] [Indexed: 05/28/2023]
Abstract
We report the first photoemission study of Fe1+xTe-the host compound of the newly discovered iron-chalcogenide superconductors (maximum Tc approximately 27 K). Our results reveal a pair of nearly electron-hole compensated Fermi pockets, strong Fermi velocity renormalization, and an absence of a spin-density-wave gap. A shadow hole pocket is observed at the "X" point of the Brillouin zone which is consistent with a long-range ordered magnetostructural ground state. No signature of Fermi surface nesting instability associated with Q=(pi/2,pi/2) is observed. Our results collectively reveal that the Fe1+xTe series is different from the undoped phases of the high Tc pnictides and likely harbor an unusual mechanism for superconductivity and magnetic order.
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Affiliation(s)
- Y Xia
- Joseph Henry Laboratories of Physics, Department of Physics, Princeton Center for Complex Materials, Princeton University, Princeton, New Jersey 08544, USA
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24
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Wu G, Wu T, Li Z, Zhao L, Liu RH, Chen H, Fang DF, Luo JL, Chen XH. Transport properties and the large anisotropic magnetoresistance of Cu(x)NbS(2) single crystals. J Phys Condens Matter 2009; 21:275601. [PMID: 21828495 DOI: 10.1088/0953-8984/21/27/275601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The transport properties of Cu(x)NbS(2) (x = 0.09, 0.44 and 0.55) single crystals were systematically studied. The in-plane and out-of-plane resistivities decrease with increasing Cu content, and a transition with hysteresis shows up for the crystals with x = 0.44 and 0.55. The thermopower and Hall coefficient of Cu(x)NbS(2) show opposite signs, indicating that there are two kinds of carriers in this system. The angular dependences of the in-plane magnetoresistance (MR(ab) = (ρ(ab)(H)-ρ(ab)(0))/ρ(ab)(0) × 100%) at different temperatures were also studied. The single crystals with x = 0.44 and 0.55 show a strong anisotropic MR(ab). For the x = 0.55 sample, MR(ab) reaches 80% with a magnetic field of 14 T applied along the c-axis, while MR(ab) is less than 5% for the magnetic field applied within the ab-plane. These results can be well understood in the light of the anisotropic Fermi surface in the multiband system.
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Affiliation(s)
- G Wu
- Hefei National Laboratory for Physical Science at Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
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25
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Abstract
Specific heat, resistivity, susceptibility, and Hall coefficient measurements were performed on high-quality single-crystalline Na_{1-delta}FeAs. This compound is found to undergo three successive phase transitions at around 52, 41, and 23 K, which correspond to structural, magnetic, and superconducting transitions, respectively. The Hall effect result indicates the development of energy gap at low temperature due to the occurrence of spin-density-wave instability. Our results provide direct experimental evidence of the magnetic ordering in the nearly stoichiometric NaFeAs.
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Affiliation(s)
- G F Chen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
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26
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Carlo JP, Uemura YJ, Goko T, Macdougall GJ, Rodriguez JA, Yu W, Luke GM, Dai P, Shannon N, Miyasaka S, Suzuki S, Tajima S, Chen GF, Hu WZ, Luo JL, Wang NL. Static magnetic order and superfluid density of RFeAs(O,F) (R=La,Nd,Ce) and LaFePO studied by muon spin relaxation: unusual similarities with the behavior of cuprate superconductors. Phys Rev Lett 2009; 102:087001. [PMID: 19257776 DOI: 10.1103/physrevlett.102.087001] [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: 05/14/2008] [Indexed: 05/27/2023]
Abstract
Muon spin relaxation measurements in iron-oxypnictide systems have revealed: (1) commensurate long-range order in undoped LaFeAsO; (2) a Bessel function line shape in LaFeAs(O0.97F0.03) which indicates possible incommensurate or stripe magnetism; (3) anomalous weak magnetism existing in superconducting LaFePO, CeFeAs(O0.084F0.16), and NdFeAs(O0.88F0.12) but absent in superconducting LaFeAs(O0.92F0.08); and (4) scaling of the superfluid density with T_{c} in the Ce-, La-, and Nd-FeAs superconductors following a nearly linear relationship found in cuprates.
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Affiliation(s)
- J P Carlo
- Department of Physics, Columbia University, New York, New York 10027, USA
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27
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Richard P, Sato T, Nakayama K, Souma S, Takahashi T, Xu YM, Chen GF, Luo JL, Wang NL, Ding H. Angle-resolved photoemission spectroscopy of the Fe-Based Ba0.6K0.4Fe2As2 high temperature superconductor: evidence for an orbital selective electron-mode coupling. Phys Rev Lett 2009; 102:047003. [PMID: 19257465 DOI: 10.1103/physrevlett.102.047003] [Citation(s) in RCA: 7] [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: 08/14/2008] [Indexed: 05/27/2023]
Abstract
We have performed an angle-resolved photoemission spectroscopy study of the new superconductor Ba0.6K0.4Fe2As2 in the low energy range. We report the observation of an anomaly around 25 meV in the dispersion of superconducting Ba0.6K0.4Fe2As2 samples that nearly vanishes above T_{c}. The energy scale of the related mode (13+/-2 meV) and its strong dependence on orbital and temperature indicates that it is unlikely related to phonons. Moreover, the momentum locations of the kink can be connected by the antiferromagnetic wave vector. Our results point towards an unconventional electronic origin of the mode and the superconducting pairing in the Fe-based superconductors, and strongly support the antiphase s-wave pairing symmetry.
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Affiliation(s)
- P Richard
- WPI Research Center, Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
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28
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Hu WZ, Dong J, Li G, Li Z, Zheng P, Chen GF, Luo JL, Wang NL. Origin of the spin density wave instability in AFe2As2 (A=Ba,Sr) as revealed by optical spectroscopy. Phys Rev Lett 2008. [PMID: 19113746 DOI: 10.1088/0256-307x/25/9/083] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
We performed optical spectroscopy measurement on single crystals of BaFe2As2 and SrFe2As2, the parent compounds of FeAs-based superconductors. Both are found to be quite metallic with fairly large plasma frequencies at high temperature. Upon entering the spin-density-wave state, the formation of partial energy gaps was clearly observed with the surprising presence of two different energy scales. A large part of the Drude component was removed by the gapping of Fermi surfaces. Meanwhile, the carrier scattering rate was even more dramatically reduced. We elaborate that the spin-density-wave instability is more likely to be driven by the Fermi surface nesting of itinerant electrons than a local-exchange mechanism.
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Affiliation(s)
- W Z Hu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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29
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Hu WZ, Dong J, Li G, Li Z, Zheng P, Chen GF, Luo JL, Wang NL. Origin of the spin density wave instability in AFe2As2 (A=Ba,Sr) as revealed by optical spectroscopy. Phys Rev Lett 2008; 101:257005. [PMID: 19113746 DOI: 10.1103/physrevlett.101.257005] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2008] [Revised: 08/05/2008] [Indexed: 05/27/2023]
Abstract
We performed optical spectroscopy measurement on single crystals of BaFe2As2 and SrFe2As2, the parent compounds of FeAs-based superconductors. Both are found to be quite metallic with fairly large plasma frequencies at high temperature. Upon entering the spin-density-wave state, the formation of partial energy gaps was clearly observed with the surprising presence of two different energy scales. A large part of the Drude component was removed by the gapping of Fermi surfaces. Meanwhile, the carrier scattering rate was even more dramatically reduced. We elaborate that the spin-density-wave instability is more likely to be driven by the Fermi surface nesting of itinerant electrons than a local-exchange mechanism.
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Affiliation(s)
- W Z Hu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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30
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Zhao J, Huang Q, de la Cruz C, Li S, Lynn JW, Chen Y, Green MA, Chen GF, Li G, Li Z, Luo JL, Wang NL, Dai P. Structural and magnetic phase diagram of CeFeAsO(1- x)F(x) and its relation to high-temperature superconductivity. Nat Mater 2008; 7:953-959. [PMID: 18953342 DOI: 10.1038/nmat2315] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Accepted: 09/26/2008] [Indexed: 05/27/2023]
Abstract
Recently, high-transition-temperature (high-Tc) superconductivity was discovered in the iron pnictide RFeAsO(1-x)F(x) (R, rare-earth metal) family of materials. We use neutron scattering to study the structural and magnetic phase transitions in CeFeAsO(1-x)F(x) as the system is tuned from a semimetal to a high-Tc superconductor through fluorine (F) doping, x. In the undoped state, CeFeAsO develops a structural lattice distortion followed by a collinear antiferromagnetic order with decreasing temperature. With increasing fluorine doping, the structural phase transition decreases gradually and vanishes within the superconductivity dome near x=0.10, whereas the antiferromagnetic order is suppressed before the appearance of superconductivity for x>0.06, resulting in an electronic phase diagram remarkably similar to that of the high-Tc copper oxides. Comparison of the structural evolution of CeFeAsO(1-x)F(x) with other Fe-based superconductors suggests that the structural perfection of the Fe-As tetrahedron is important for the high-Tc superconductivity in these Fe pnictides.
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Affiliation(s)
- Jun Zhao
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996-1200, USA
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31
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Zhao J, Yao DX, Li S, Hong T, Chen Y, Chang S, Ratcliff W, Lynn JW, Mook HA, Chen GF, Luo JL, Wang NL, Carlson EW, Hu J, Dai P. Low energy spin waves and magnetic interactions in SrFe2As2. Phys Rev Lett 2008; 101:167203. [PMID: 18999708 DOI: 10.1103/physrevlett.101.167203] [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: 08/18/2008] [Indexed: 05/27/2023]
Abstract
We report inelastic neutron scattering studies of magnetic excitations in antiferromagnetically ordered SrFe2As2 (T_{N}=200-220 K), the parent compound of the FeAs-based superconductors. At low temperatures (T=7 K), the magnetic spectrum S(Q,Planck's omega) consists of a Bragg peak at the elastic position (Planck's omega=0 meV), a spin gap (Delta< or =6.5 meV), and sharp spin-wave excitations at higher energies. Based on the observed dispersion relation, we estimate the effective magnetic exchange coupling using a Heisenberg model. On warming across T_{N}, the low-temperature spin gap rapidly closes, with weak critical scattering and spin-spin correlations in the paramagnetic state. The antiferromagnetic order in SrFe2As2 is therefore consistent with a first order phase transition, similar to the structural lattice distortion.
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Affiliation(s)
- Jun Zhao
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, TN 37996-1200, USA
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32
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Li G, Hu WZ, Dong J, Li Z, Zheng P, Chen GF, Luo JL, Wang NL. Probing the superconducting energy gap from infrared spectroscopy on a Ba0.6K0.4Fe2As2 single crystal with Tc=37 K. Phys Rev Lett 2008; 101:107004. [PMID: 18851247 DOI: 10.1103/physrevlett.101.107004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2008] [Indexed: 05/26/2023]
Abstract
We performed optical spectroscopy measurement on a superconducting Ba0.6K0.4Fe2As2 single crystal with T{c}=37 K. Formation of the superconducting energy gaps in the far-infrared reflectance spectra below T{c} is clearly observed. A flat and close to unity reflectance is observed roughly below 150 cm;{-1} for T<<T{c}, following an s-wave pairing line shape. A more rapid decrease occurs near 200 cm;{-1}, leading to a peak in the ratio of the reflectance at T<<T{c} over that for T>or=T{c}. We determined the absolute value of the penetration depth at 10 K as lambda approximately 2000+/-80 A. A spectral weight analysis shows that the Ferrell-Glover-Tinkham sum rule is satisfied at low energy scale, less than 6Delta.
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Affiliation(s)
- G Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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33
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Xu XF, Xu ZA, Liu TJ, Fobes D, Mao ZQ, Luo JL, Liu Y. Band-dependent normal-state coherence in Sr2RuO4: evidence from Nernst effect and thermopower measurements. Phys Rev Lett 2008; 101:057002. [PMID: 18764419 DOI: 10.1103/physrevlett.101.057002] [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: 01/22/2008] [Indexed: 05/26/2023]
Abstract
We present the first measurement on the Nernst effect in the normal state of the odd-parity, spin-triplet superconductor Sr2RuO4. Below 100 K, the Nernst signal was found to be negative, large, and, as a function of magnetic field, nonlinear. Its magnitude increases with the decreasing temperature until reaching a maximum around T* approximately equal to 20-25 K, below which it starts to decrease linearly as a function of temperature. The large value of the Nernst signal appears to be related to the multiband nature of the normal state and the nonlinearity to band-dependent magnetic fluctuation in Sr2RuO4. We argue that the sharp decrease in the Nernst signal below T* is due to the suppression of quasiparticle scattering and the emergence of band-dependent coherence in the normal state.
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Affiliation(s)
- X F Xu
- Department of Physics, Zhejiang University, Hangzhou, China
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34
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Chen GF, Li Z, Li G, Zhou J, Wu D, Dong J, Hu WZ, Zheng P, Chen ZJ, Yuan HQ, Singleton J, Luo JL, Wang NL. Superconducting properties of the Fe-based layered superconductor LaFeAsO0.9F0.1-delta. Phys Rev Lett 2008; 101:057007. [PMID: 18764424 DOI: 10.1103/physrevlett.101.057007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2008] [Indexed: 05/15/2023]
Abstract
We have employed a new route to synthesize single phase F-doped LaOFeAs compound and confirmed the superconductivity above 20 K in this Fe-based system. We show that the new superconductor has a rather high upper critical field of over 50 T. A clear signature of superconducting gap opening below T(c) was observed in the far-infrared reflectance spectra, with 2Delta/kT(c) approximately 3.5-4.2. Furthermore, we show that the new superconductor has electron-type conducting carriers with a rather low-carrier density.
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Affiliation(s)
- G F Chen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
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35
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Wu T, Wang CH, Wu G, Fang DF, Luo JL, Liu GT, Chen XH. Giant anisotropy of the magnetoresistance and the 'spin valve' effect in antiferromagnetic Nd(2-x)Ce(x)CuO(4). J Phys Condens Matter 2008; 20:275226. [PMID: 21694387 DOI: 10.1088/0953-8984/20/27/275226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We have studied anisotropic magnetoresistance (MR) and magnetization with a rotating magnetic field (B) within the CuO(2) plane in lightly doped AF Nd(2-x)Ce(x)CuO(4). A giant anisotropy in the MR is observed at low temperature, below 5 K. The c-axis resistivity can be tuned over about one order of magnitude just by changing the B direction within the CuO(2) plane, and a scaling behavior for the out-of-plane and in-plane MR is found. A 'spin valve' effect is proposed for explaining the giant anisotropy of the out-of-plane MR and the evolution of the scaling parameters with the external field. It is found that the field-induced spin-flop transition of the Nd(3+) layer under high magnetic field is the key to understanding the giant anisotropy. These results suggest that a novel entanglement of charge and spin dominates the underlying physics.
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Affiliation(s)
- T Wu
- Hefei National Laboratory for Physical Science at Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
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36
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Chen GF, Li Z, Wu D, Li G, Hu WZ, Dong J, Zheng P, Luo JL, Wang NL. Superconductivity at 41 K and its competition with spin-density-wave instability in layered CeO1-xFxFeAs. Phys Rev Lett 2008; 100:247002. [PMID: 18643616 DOI: 10.1103/physrevlett.100.247002] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Revised: 05/14/2008] [Indexed: 05/15/2023]
Abstract
A series of layered CeO1-xFxFeAs compounds with x=0 to 0.20 are synthesized by the solid state reaction method. Similar to the LaOFeAs, the pure CeOFeAs shows a strong resistivity anomaly near 145 K, which was ascribed to the spin-density-wave instability. F doping suppresses this instability and leads to the superconducting ground state. Most surprisingly, the superconducting transition temperature could reach as high as 41 K. Such a high T_{c} strongly challenges the classic BCS theory based on the electron-phonon interaction. The closeness of the superconducting phase to the spin-density-wave instability suggests that the magnetic fluctuation plays a key role in the superconducting pairing mechanism. The study also reveals that the Ce 4f electrons form local moments and are ordered antiferromagnetically below 4 K, which could coexist with superconductivity.
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Affiliation(s)
- G F Chen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, People's Republic of China
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37
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Li Z, Li G, Wang NL, Luo JL. The metal-insulator-like and insulator-metal-like behaviors in antimony. J Phys Condens Matter 2008; 20:235232. [PMID: 21694323 DOI: 10.1088/0953-8984/20/23/235232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The resistivity and Hall resistivity of semimetallic antimony were measured from 2 to 300 K in magnetic fields up to 14 T. We found that in low field, the resistivity shows metallic behavior. In a modest field, the resistivity decreases to a minimum and then increases with decreasing temperature, showing a metal-insulator-like transition. In high field, the resistivity drops at low temperatures, showing an insulator-metal-like transition. The metal-insulator-like behavior can be explained by the competition of zero field resistivity and magneto-resistance, which is reciprocal to the zero field resistivity. The insulator-metal-like behavior can be explained by the imbalance of two carrier densities which changes the magneto-resistance from being reciprocal to proportional to the zero field resistivity.
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Affiliation(s)
- Z Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, People's Republic of China
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38
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Qian D, Wray L, Hsieh D, Viciu L, Cava RJ, Luo JL, Wu D, Wang NL, Hasan MZ. Complete d-band dispersion relation in sodium cobaltates. Phys Rev Lett 2006; 97:186405. [PMID: 17155565 DOI: 10.1103/physrevlett.97.186405] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2006] [Indexed: 05/12/2023]
Abstract
We utilize fine-tuned polarization selection coupled with excitation-energy variation of photoelectron signal to image the complete d-band dispersion relation in sodium cobaltates. A hybridization gap anticrossing is observed along the Brillouin zone corner and the full quasiparticle band is found to emerge as a many-body entity lacking a pure orbital polarization. At low dopings, the quasiparticle bandwidth (Fermion scale, many-body E(F) approximately 0.25 eV) is found to be smaller than most known oxide metals. The low-lying density of states is found to be in agreement with bulk-sensitive thermodynamic measurements for nonmagnetic dopings where the 2D Luttinger theorem is also observed to be satisfied.
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Affiliation(s)
- D Qian
- Department of Physics, Joseph Henry Laboratories, Princeton University, Princeton, New Jersey 08544, USA
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39
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Zhao SR, Xu ZA, Takeya H, Hirata K, Luo JL. Reentrant behaviour in Y-doped Ho(0.75)Y(0.25)Ni(2)B(2)C single crystal. J Phys Condens Matter 2006; 18:8533-8539. [PMID: 21690906 DOI: 10.1088/0953-8984/18/37/011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The transport and superconducting properties of Ho(0.75)Y(0.25)Ni(2)B(2)C single crystals were investigated to study the competing effects between superconductivity and magnetism. The superconducting transition temperature T(c) is 7.6 K, determined from the resistivity transition; meanwhile, the commensurate antiferromagnetic (AFM) transition occurs at T(N) of 3.9 K, which is lower than that of pure HoNi(2)B(2)C (T(N)≈5 K). Ho(0.75)Y(0.25)Ni(2)B(2)C reentered into the normal state at T(m) (T(N)<T(m)<T(c)) when small magnetic fields were applied along the crystallographic c-axis. In contrast to the case in HoNi(2)B(2)C, the reentrant behaviour for Ho(0.75)Y(0.25)Ni(2)B(2)C only appears when the applied field H is along the c-axis, and the reentrant peak position T(P)(H) shifts to lower temperature with increasing applied field. We suggest that the disorder of magnetic structure induced by Y doping may account for the significant difference in the reentrant behaviour between Ho(0.75)Y(0.25)Ni(2)B(2)C and HoNi(2)B(2)C. Moreover, there does not exist a deep minimum in the upper critical field H(c2)(T) line at T(N) of 3.9 K for either [Formula: see text] or [Formula: see text]. The H-T phase diagram is derived and discussed.
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Affiliation(s)
- S R Zhao
- Department of Physics, Zhejiang University, Hangzhou 310027, People's Republic of China
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40
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Wang CH, Chen XH, Wu T, Luo XG, Wang GY, Luo JL. In-plane ferromagnetism in charge-ordering Na0.55CoO2. Phys Rev Lett 2006; 96:216401. [PMID: 16803257 DOI: 10.1103/physrevlett.96.216401] [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: 12/20/2005] [Indexed: 05/10/2023]
Abstract
The magnetic and transport properties are systematically studied on the single crystal Na(0.55)CoO2 with the resistivity divergence below 50 K. A weak ferromagnetic ordering is observed in susceptibility below 20 K with the magnetic field parallel to the Co-O plane, while no such ferromagnetic ordering is observed with the field perpendicular to the Co-O plane. It gives evidence for the existence of in-plane ferromagnetism below 20 K. The observed magnetoresistance of 30% at the field of 6 T at low temperatures indicates an unexpectedly strong spin-charge coupling in the triangle lattice NaxCoO2 system.
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Affiliation(s)
- C H Wang
- Hefei National Laboratory for Physical Science at Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
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41
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Qian D, Hsieh D, Wray L, Chuang YD, Fedorov A, Wu D, Luo JL, Wang NL, Viciu L, Cava RJ, Hasan MZ. Low-lying quasiparticle states and hidden collective charge instabilities in parent cobaltate superconductors. Phys Rev Lett 2006; 96:216405. [PMID: 16803261 DOI: 10.1103/physrevlett.96.216405] [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: 12/27/2005] [Indexed: 05/10/2023]
Abstract
We report a state-of-the-art photoemission (angle-resolved photoemission spectroscopy) study of high quality single crystals of NaxCoO2 the series focusing on the fine details of the low-energy states. The Fermi velocity is found to be small (<0.5 eV A) and only weakly anisotropic over the Fermi surface at all dopings, setting the size of the pair wave function to be on the order of 10-20 nm. In the low-doping regime, the exchange interlayer splitting vanishes and two-dimensional collective instabilities such as 120 degrees -type fluctuations become kinematically allowed. Our results suggest that the unusually small Fermi velocity and the unique symmetry of kinematic instabilities distinguish cobaltates from most other oxide superconductors.
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Affiliation(s)
- D Qian
- Department of Physics, Joseph Henry Laboratories, Princeton University, Princeton, New Jersey 08544, USA
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42
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Abstract
A theoretical model was developed on basis of nonequilibrium thermodynamics, dislocation kinetics, and electrochemistry, which may lead to the quantitative assessment of material loss produced by the synergism of mechanical and electrochemical factors in an erosion-corrosion process, As predicted by this model, the synergistic effect results mainly from the interaction of two irreversible fluxes, namely, the anodic dissolution current density and the plastic flowing in the surface layer caused by dynamic plastic deformation. An enhanced anodic dissolution flux is induced by the dynamic surface plastic deformation resulting from the impingement of solid particles, which can be correlated to the wastage rate due to the mechanical erosion. Meanwhile, the anodic current present at the electrode surface, in turn, can increase the mobility of dislocation and reduce the resistance in the surface layer against plastic deformation. Such an effect is demonstrated by the hardness degradation of metals in corrosive media. Theoretical analysis indicates that the corrosion-induced hardness degradation is a linear function of the logarithm of anodic current density. The degradation of mechanical erosion resistance with decreasing hardness suggests that the corrosion-enhanced erosion may result from the degradation in hardness of target material induced by the anodic dissolution and the corresponding wastage is also a linear function of the logarithm of anodic current density. The theoretical predictions were compared with the experimental results of carbon steels obtained form the slurry-erosion tests and the micro-hardness measurements. The results indicate that the hardness degradation in corrosive media is mainly controlled by the anodic current density and is almost independent of the polarization behavior of steels.
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Affiliation(s)
- B T Lu
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, Canada T6G 2G6
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43
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Qian D, Wray L, Hsieh D, Wu D, Luo JL, Wang NL, Kuprin A, Fedorov A, Cava RJ, Viciu L, Hasan MZ. Quasiparticle dynamics in the vicinity of metal-insulator phase transition in NaxCoO2. Phys Rev Lett 2006; 96:046407. [PMID: 16486860 DOI: 10.1103/physrevlett.96.046407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2005] [Indexed: 05/06/2023]
Abstract
Layered cobaltates embody novel realizations of correlated matter on a spin-1/2 triangular lattice. We report a high-resolution systematic photoemission study of the insulating cobaltates. The observation of a single-particle gap opening and band folding provides direct evidence of anisotropic particle-hole instability on the Fermi surface due to its unique topology. Overlap of the measured Fermi surface is observed with the square root 3xsquare root 3 charge-order Brillouin zone near x=1/3 but not at x=1/2 where the insulating transition is actually observed. Unlike conventional density waves, charge stripes, or band insulators, the onset of the gap depends on the quasiparticle's quantum coherence which is found to occur well below the disorder-order symmetry breaking temperature of the crystal (the first known example of its kind).
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Affiliation(s)
- D Qian
- Department of Physics, Joseph Henry Laboratories of Physics, Princeton University, Princeton, New Jersey 08544, USA
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44
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Luo JL, Wang NL, Liu GT, Wu D, Jing XN, Hu F, Xiang T. Metamagnetic transition in Na 0.85 CoO2 single crystals. Phys Rev Lett 2004; 93:187203. [PMID: 15525203 DOI: 10.1103/physrevlett.93.187203] [Citation(s) in RCA: 5] [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: 04/20/2004] [Indexed: 05/24/2023]
Abstract
We report the magnetization, specific heat, and transport measurements of a high quality Na(0.85)CoO2 single crystal in applied magnetic fields up to 14 T. At high temperatures, the system is in a paramagnetic phase. It undergoes a magnetic phase transition below approximately 20 K. For the field H||c, the measurement data of magnetization, specific heat, and magnetoresistance reveal a metamagnetic transition from an antiferromagnetic state to a quasiferromagnetic state at about 8 T at low temperatures. However, no transition is observed in the magnetization measurements up to 14 T for H perpendicular c. The low temperature magnetic phase diagram of Na(0.85)CoO2 is determined.
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Affiliation(s)
- J L Luo
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
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45
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Njalsson R, Norgren S, Larsson A, Huang CS, Anderson ME, Luo JL. Cooperative binding of gamma-glutamyl substrate to human glutathione synthetase. Biochem Biophys Res Commun 2001; 289:80-4. [PMID: 11708780 DOI: 10.1006/bbrc.2001.5961] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Human glutathione synthetase is responsible for catalyzing the final step in glutathione biosynthesis. It is a homodimer with a monomer subunit MW of 52 kDa. Kinetic analysis reveals a departure from linearity of the Lineweaver-Burk double reciprocal plot for the binding of gamma-glutamyl substrate, indicating cooperative binding. The measured apparent K(m) values for gamma-glutamyl-alpha-aminobutyrate (an analog of gamma-glutamyl-alpha-aminobutyrate) are 63 and 164 microM, respectively. Neither ATP (K(m) of 248 microM) nor glycine (K(m) of 452 microM) exhibits such cooperative binding behavior. Although ATP is proposed to play a key role in the sequential binding of gamma-glutamyl substrate to the enzyme, the cooperative binding of the gamma-glutamyl substrate is not affected by alterations of ATP concentration. Quantitative analysis of the kinetic results for gamma-glutamyl substrate binding gives a Hill coefficient (h) of 0.75, indicating negative cooperativity. Our studies, for the first time, show that human glutathione synthetase is an allosteric enzyme with cooperative binding for gamma-glutamyl substrate.
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Affiliation(s)
- R Njalsson
- Department of Pediatrics, Karolinska Institute, Huddinge University Hospital, 141 86 Huddinge, Sweden
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46
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Luo JL, Tong WM, Yoon JH, Hergenhahn M, Koomagi R, Yang Q, Galendo D, Pfeifer GP, Wang ZQ, Hollstein M. UV-induced DNA damage and mutations in Hupki (human p53 knock-in) mice recapitulate p53 hotspot alterations in sun-exposed human skin. Cancer Res 2001; 61:8158-63. [PMID: 11719445] [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] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
The major etiological agent contributing to human nonmelanoma skin cancer is sunlight. The p53 tumor suppressor gene is usually mutated in these tumors, and the mutations are "UV signature" single or tandem transitions at dipyrimidine sequences in the DNA-binding domain (DBD). Cells that harbor these characteristic mutations are already present in sun-exposed skin areas of healthy individuals, and small epidermal patches that are immunoreactive to anti-p53 antibody accrue as exposure increases. To explore carcinogen-specific human p53 mutation patterns experimentally, we generated a knock-in (Hupki) mouse in which the murine DBD of the p53 gene has been replaced by the homologous human p53 DBD segment; thus, the precise base sequence context frequently targeted by mutagens or endogenous mutagenic processes in human carcinogenesis is present in this strain (J. L. Luo et al., Oncogene, 20: 320-328, 2001). Here we show that when epidermal cells of Hupki mice (p53(ki/ki)) are irradiated in vivo with a single acute dose of UVB light, they accumulate UV photoproducts at the same locations of the p53 gene as human cells. Chronic exposure of Hupki mice (4.5 kJ/m(2) 5x/week for 4 weeks) results in the appearance of cell patches that stain intensely with the anti-p53 antiserum CM1. DNA preparations from 2 cm(2) sections of chronically irradiated Hupki epidermis harbor C to T and CC to TT mutations at two mutation hotspots identified in human skin cancer, one at codons 278-279, and one at codons 247-248; the latter is the most frequent UVB-associated mutation site in humans but not in p53 wild-type mice. Thus, Hupki keratinocytes with these p53 mutations encode an aberrant DBD identical in amino acid sequence to the mutant p53 molecules in human UV-induced tumors. The Hupki mouse model offers a new experimental tool in molecular epidemiology and biomedical research.
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Affiliation(s)
- J L Luo
- German Cancer Research Center, Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany
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Ireson C, Orr S, Jones DJ, Verschoyle R, Lim CK, Luo JL, Howells L, Plummer S, Jukes R, Williams M, Steward WP, Gescher A. Characterization of metabolites of the chemopreventive agent curcumin in human and rat hepatocytes and in the rat in vivo, and evaluation of their ability to inhibit phorbol ester-induced prostaglandin E2 production. Cancer Res 2001; 61:1058-64. [PMID: 11221833] [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: 02/19/2023]
Abstract
Curcumin, the yellow pigment in turmeric, has been shown to prevent malignancies in a variety of tissues in rodents, especially in the intestinal tract. Pharmacological activities of curcumin in cells in situ germane to chemoprevention, such as inhibition of expression of cyclooxygenase-2 (COX-2), require drug concentrations in the 10(-5) - 10(-4) M range. The systemic bioavailability of curcumin is low, so that its pharmacological activity may be mediated, in part, by curcumin metabolites. To investigate this possibility, we compared curcumin metabolism in human and rat hepatocytes in suspension with that in rats in vivo. Analysis by high-performance liquid chromatography with detection at 420 and 280 nm permitted characterization of metabolites with both intact diferoylmethane structure and increased saturation of the heptatrienone chain. Chromatographic inferences were corroborated by mass spectrometry. The major metabolites in suspensions of human or rat hepatocytes were identified as hexahydrocurcumin and hexahydrocurcuminol. In rats, in vivo, curcumin administered i.v. (40 mg/kg) disappeared from the plasma within 1 h of dosing. After p.o. administration (500 mg/kg), parent drug was present in plasma at levels near the detection limit. The major products of curcumin biotransformation identified in rat plasma were curcumin glucuronide and curcumin sulfate whereas hexahydrocurcumin, hexahydrocurcuminol, and hexahydrocurcumin glucuronide were present in small amounts. To test the hypothesis that curcumin metabolites resemble their progenitor in that they can inhibit COX-2 expression, curcumin and four of its metabolites at a concentration of 20 microM were compared in terms of their ability to inhibit phorbol ester-induced prostaglandin E2 (PGE2) production in human colonic epithelial cells. Curcumin reduced PGE2 levels to preinduction levels, whereas tetrahydrocurcumin, previously shown to be a murine metabolite of curcumin, hexahydrocurcumin, and curcumin sulfate, had only weak PGE2 inhibitory activity, and hexahydrocurcuminol was inactive. The results suggest that (a) the major products of curcumin biotransformation by hepatocytes occur only at low abundance in rat plasma after curcumin administration; and (b) metabolism of curcumin by reduction or conjugation generates species with reduced ability to inhibit COX-2 expression. Because the gastrointestinal tract seems to be exposed more prominently to unmetabolized curcumin than any other tissue, the results support the clinical evaluation of curcumin as a colorectal cancer chemopreventive agent.
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Affiliation(s)
- C Ireson
- Medical Research Council Toxicology Unit, University of Leicester, United Kingdom
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Luo JL, Yang Q, Tong WM, Hergenhahn M, Wang ZQ, Hollstein M. Knock-in mice with a chimeric human/murine p53 gene develop normally and show wild-type p53 responses to DNA damaging agents: a new biomedical research tool. Oncogene 2001; 20:320-8. [PMID: 11313961 DOI: 10.1038/sj.onc.1204080] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2000] [Revised: 11/02/2000] [Accepted: 11/02/2000] [Indexed: 11/09/2022]
Abstract
The high prevalence and great diversity of p53 tumor suppressor gene mutations in human tumors call for development of therapeutic molecules that rescue function of aberrant p53 protein. P53 mutations also offer new approaches to the study of the origins of mutations in human cancer. An experimental mouse model with a genetically modified but normal functioning p53 gene harboring the human rather than the murine core domain, would be of considerable benefit to research on both cancer therapeutics and etiology; however, it is uncertain whether such mice would permit biological functions of p53 to be retained. Using a Cre/lox P gene-targeting approach, we have constructed a human p53 knock-in (hupki) mouse strain in which exons 4-9 of the endogenous mouse p53 allele were replaced with the homologous, normal human p53 gene sequence. The chimeric p53 allele (p53(KI)) is properly spliced, transcribed in various tissues at levels equivalent to wild-type mice, and yields cDNA with the anticipated sequence, that is, with a core domain matching that of humans. The hupki p53 protein binds to p53 consensus sequences in gel mobility shift assays and accumulates in the nucleus of hupki fibroblasts in response to UV irradiation, as is characteristic of wild-type p53. Induction of various p53-regulated genes in spleen of gamma-irradiated homozygous hupki mice (p53(KI/KI)), and the kinetics of p53-dependent apoptosis in thymocytes are similar to results with wild-type (p53(+/+)) mice, further indicating normal p53 pathway function in the hupki strain. The mice are phenotypically normal and do not develop spontaneous tumors at an early age, in contrast to knock-out (p53(-/-)) strains with a defective p53 gene. The chimeric (p53(KI)) allele thus appears to provide a biological equivalent to the endogenous murine (p53(+)) gene. This strain is a unique tool for examining in vivo spontaneous and induced mutations in human p53 gene sequences for comparison with published human tumor p53 mutation spectra. In addition, the hupki strain paves the way for mouse models in pre-clinical testing of pharmaceuticals designed to modulate DNA-binding activity of human p53.
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Affiliation(s)
- J L Luo
- Department of Genetic Alterations in Carcinogenesis (C0700), German Cancer Research Center (Deutsches Krebsforschungszentrum), Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany
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Luo JL, Xiao JY, Tian YQ, Zhao SP, Liu JW, Tao ZD. [MDM2 gene expression in nasopharyngeal carcinoma and its relationship with p53 protein expression and EB virus latent infection]. Lin Chuang Er Bi Yan Hou Ke Za Zhi 2000; 14:507-9. [PMID: 12563945] [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: 02/28/2023]
Abstract
OBJECTIVE To define the expression levels of MDM2 gene in nasopharyngeal carcinoma (NPC) and its relationship with p53 protein expression and EB virus latent infection. METHOD MDM2 gene expression at mRNA and protein levels, p53 protein and EB virus DNA were detected by nonradioactive in situ hybridization (ISH), immunohistochemistry(IHC) and polymerase chain reaction (PCR) separately in 46 cases of NPC tissues and 12 cases of chronic inflammation of nasopharyngeal epithelium (CINE). RESULT Fourteen cases of NPC showed MDM2 mRNA and protein overexpression, 38 cases were p53 protein positive, and 43 cases were EBV-DNA positive. Neither MDM2 nor p53 protein was expressed in any case of CINE. MDM2 expression was significantly related to p53 protein expression (P < 0.05), but not to EB virus latent infection in NPC. CONCLUSION MDM2 gene may play an important role in the pathogenesis of NPC through interacting with p53 protein.
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Affiliation(s)
- J L Luo
- Research Laboratory of Otolaryngology, Xiangya Hospital, Hunan Medical University, Changsha 410008
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Luo JL, Huang CS, Babaoglu K, Anderson ME. Novel kinetics of mammalian glutathione synthetase: characterization of gamma-glutamyl substrate cooperative binding. Biochem Biophys Res Commun 2000; 275:577-81. [PMID: 10964706 DOI: 10.1006/bbrc.2000.3337] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Glutathione (GSH) synthetase [L-gamma-glutamyl-L-cysteinyl:glycine ligase (ADP-forming), EC 6.3.2.3] catalyzes the final step in GSH biosynthesis. Mammalian glutathione synthetase is a homodimer with each subunit containing an active site. We report the detailed kinetic data for purified recombinant rat glutathione synthetase. It has the highest specific activity (11 micromol/min/mg) reported for any mammalian glutathione synthetase. The apparent K(m) values for ATP and glycine are 37 and 913 microM, respectively. The Lineweaver-Burk double reciprocal plot for gamma-glutamyl substrate binding revealed a departure from linearity indicating cooperative binding. Quantitative analysis of the kinetic results for gamma-glutamyl substrate binding gives a Hill coefficient (h) of 0. 576, which shows the negative cooperativity. Neither ATP, the other substrate involved in forming the enzyme-bound gamma-glutamyl phosphate intermediate, nor glycine, which attacks this intermediate to form GSH, exhibit any cooperativity. The cooperative binding of gamma-glutamyl substrate is not affected by ATP concentration. Thus, mammalian glutathione synthetase is an allosteric enzyme.
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Affiliation(s)
- J L Luo
- Department of Microbiology and Molecular Cell Sciences, University of Memphis, Memphis, Tennessee 38152, USA
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