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Chen L, Zhao W, Xing K, You M, Wang X, Zheng RK. Anomalous Hall effect in Nd-doped Bi 1.1Sb 0.9STe 2 topological insulator single crystals. Phys Chem Chem Phys 2024; 26:2638-2645. [PMID: 38174415 DOI: 10.1039/d3cp05850f] [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: 01/05/2024]
Abstract
Topological insulators are emerging materials with insulating bulk and symmetry protected nontrivial surface states. One of the most fascinating transport behaviors in a topological insulator is the quantum anomalous Hall effect, which has been observed in magnetic-topological-insulator-based devices. In this work, we report successful doping of rare-earth element Nd into Bi1.1Sb0.9STe2 bulk-insulating topological insulator single crystals, in which the Nd moments are ferromagnetically ordered at ∼100 K. Benefiting from the in-bulk-gap Fermi level, electronic transport behaviors dominated by the topological surface states are observed in the ferromagnetic region. At low temperatures, strong Shubnikov-de Haas oscillations with a nontrivial Berry phase are observed. The topological insulator with long range magnetic ordering in Nd-doped Bi1.1Sb0.9STe2 single crystals provides a good platform for quantum transport studies and spintronic applications.
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Affiliation(s)
- Lei Chen
- School of Physics and Materials Science, Guangzhou University, Guangzhou 510006, China.
| | - Weiyao Zhao
- Department of Materials Science & Engineering, and ARC Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Clayton, VIC 3800, Australia
| | - Kaijian Xing
- School of Physics & Astronomy, Monash University, Clayton, VIC 3800, Australia
| | - Mengyun You
- Institute for Superconducting and Electronic Materials, and ARC Centre of Excellence in Future Low-Energy Electronics Technologies, Innovation Campus, University of Wollongong, NSW 2500, Australia
| | - Xiaolin Wang
- Institute for Superconducting and Electronic Materials, and ARC Centre of Excellence in Future Low-Energy Electronics Technologies, Innovation Campus, University of Wollongong, NSW 2500, Australia
| | - Ren-Kui Zheng
- School of Physics and Materials Science, Guangzhou University, Guangzhou 510006, China.
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Li Y, Wang YY, Xing K, Li SS. [Current situation and the latest progress in the treatment of pyoderma gangrenosum]. Zhonghua Shao Shang Yu Chuang Mian Xiu Fu Za Zhi 2022; 38:574-579. [PMID: 35764585 DOI: 10.3760/cma.j.cn501225-20220330-00108] [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: 06/15/2023]
Abstract
Pyoderma gangrenosum (PG) is a rare chronic inflammatory non-infectious skin dermatosis, and there is no clear treatment guideline for this disease at home and abroad. There are a variety of clinical treatment methods for PG, including local therapy and systemic application of glucocorticoids, immunosuppressants, intravenous immuno- globulin, and biologics. Glucocorticoids are the first-line drugs commonly used in clinical practice, and immunosuppressants can be used alone or in combination with glucocorticoids. In recent years, more and more evidence has shown that biologics are a new trend in the treatment of PG, mainly including tumor necrosis factor α inhibitors, interleukin-1 (IL-1) inhibitors, IL-12/23 inhibitors, IL-17 inhibitors, rituximab, and small molecular inhibitors. This article summarizes the current status and latest progress in the treatment of PG, hoping to provide clinicians with ideas for the treatment of PG.
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Affiliation(s)
- Y Li
- Department of Dermatology, the First Hospital of Jilin University, Changchun 130021, China
| | - Y Y Wang
- Department of Dermatology, the First Hospital of Jilin University, Changchun 130021, China
| | - K Xing
- Department of Dermatology, the First Hospital of Jilin University, Changchun 130021, China
| | - S S Li
- Department of Dermatology, the First Hospital of Jilin University, Changchun 130021, China
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Li W, Shahbazi M, Xing K, Tesfamichael T, Motta N, Qi DC. Highly Sensitive NO2 Gas Sensors Based on MoS2@MoO3 Magnetic Heterostructure. Nanomaterials 2022; 12:nano12081303. [PMID: 35458010 PMCID: PMC9027905 DOI: 10.3390/nano12081303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 04/07/2022] [Accepted: 04/08/2022] [Indexed: 12/16/2022]
Abstract
Recently, two-dimensional (2D) materials and their heterostructures have attracted considerable attention in gas sensing applications. In this work, we synthesized 2D MoS2@MoO3 heterostructures through post-sulfurization of α-MoO3 nanoribbons grown via vapor phase transport (VPT) and demonstrated highly sensitive NO2 gas sensors based on the hybrid heterostructures. The morphological, structural, and compositional properties of the MoS2@MoO3 hybrids were studied by a combination of advanced characterization techniques revealing a core-shell structure with the coexistence of 2H-MoS2 multilayers and intermediate molybdenum oxysulfides on the surface of α-MoO3. The MoS2@MoO3 hybrids also exhibit room-temperature ferromagnetism, revealed by vibrating sample magnetometry (VSM), as a result of the sulfurization process. The MoS2@MoO3 gas sensors display a p-type-like response towards NO2 with a detection limit of 0.15 ppm at a working temperature of 125 °C, as well as superb selectivity and reversibility. This p-type-like sensing behavior is attributed to the heterointerface of MoS2-MoO3 where interfacial charge transfer leads to a p-type inversion layer in MoS2, and is enhanced by magnetic dipole interactions between the paramagnetic NO2 and the ferromagnetic sensing layer. Our study demonstrates the promising application of 2D molybdenum hybrid compounds in gas sensing applications with a unique combination of electronic and magnetic properties.
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Affiliation(s)
- Wei Li
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, QLD 4001, Australia; (W.L.); (M.S.)
- Centre for Materials Science, Queensland University of Technology, Brisbane, QLD 4001, Australia
| | - Mahboobeh Shahbazi
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, QLD 4001, Australia; (W.L.); (M.S.)
| | - Kaijian Xing
- School of Physics and Astronomy, Monash University, Clayton, VIC 3800, Australia;
| | - Tuquabo Tesfamichael
- Centre for Materials Science, Queensland University of Technology, Brisbane, QLD 4001, Australia
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD 4001, Australia
- Correspondence: (T.T.); (N.M.); (D.-C.Q.)
| | - Nunzio Motta
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, QLD 4001, Australia; (W.L.); (M.S.)
- Centre for Materials Science, Queensland University of Technology, Brisbane, QLD 4001, Australia
- Correspondence: (T.T.); (N.M.); (D.-C.Q.)
| | - Dong-Chen Qi
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, QLD 4001, Australia; (W.L.); (M.S.)
- Centre for Materials Science, Queensland University of Technology, Brisbane, QLD 4001, Australia
- Correspondence: (T.T.); (N.M.); (D.-C.Q.)
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Gu H, He X, Wu Y, Deng S, Jiang Y, Yu J, Deng Z, Xing K, Wang Z. Examining differentiation of sympatric
Schizothorax
fishes reveals low differentiation in internal compared to external feeding traits. J Zool (1987) 2022. [DOI: 10.1111/jzo.12956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- H. Gu
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education) Key Laboratory of Aquatic Science of Chongqing School of Life Sciences Southwest University Chongqing China
| | - X. He
- Sichuan Lubei Biotechnology Company Limited Chengdu China
| | - Y. Wu
- Sichuan Lubei Biotechnology Company Limited Chengdu China
| | - S. Deng
- Liangshan Kehua Water Ecology Company Limited Xichang China
| | - Y. Jiang
- Butuo Agriculture and Rural Affairs Bureau Butuo China
| | - J. Yu
- Zhaojue Agriculture and Rural Affairs Bureau Zhaojue China
| | - Z. Deng
- Liangshan Kehua Water Ecology Company Limited Xichang China
| | - K. Xing
- Xichang Agriculture and Rural Affairs Bureau Xichang China
| | - Z. Wang
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education) Key Laboratory of Aquatic Science of Chongqing School of Life Sciences Southwest University Chongqing China
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Di Bernardo I, Blyth J, Watson L, Xing K, Chen YH, Chen SY, Edmonds MT, Fuhrer MS. Defects, band bending and ionization rings in MoS 2. J Phys Condens Matter 2022; 34:174002. [PMID: 35081526 DOI: 10.1088/1361-648x/ac4f1d] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 01/26/2022] [Indexed: 06/14/2023]
Abstract
Chalcogen vacancies in transition metal dichalcogenides are widely acknowledged as both donor dopants and as a source of disorder. The electronic structure of sulphur vacancies in MoS2however is still controversial, with discrepancies in the literature pertaining to the origin of the in-gap features observed via scanning tunneling spectroscopy (STS) on single sulphur vacancies. Here we use a combination of scanning tunnelling microscopy and STS to study embedded sulphur vacancies in bulk MoS2crystals. We observe spectroscopic features dispersing in real space and in energy, which we interpret as tip position- and bias-dependent ionization of the sulphur vacancy donor due to tip induced band bending. The observations indicate that care must be taken in interpreting defect spectra as reflecting in-gap density of states, and may explain discrepancies in the literature.
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Affiliation(s)
- Iolanda Di Bernardo
- Australian Research Council Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Clayton, 3800, VIC, Australia
- School of Physics and Astronomy, Monash University, Clayton, 3800, VIC, Australia
| | - James Blyth
- Australian Research Council Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Clayton, 3800, VIC, Australia
- School of Physics and Astronomy, Monash University, Clayton, 3800, VIC, Australia
| | - Liam Watson
- Australian Research Council Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Clayton, 3800, VIC, Australia
- School of Physics and Astronomy, Monash University, Clayton, 3800, VIC, Australia
| | - Kaijian Xing
- School of Physics and Astronomy, Monash University, Clayton, 3800, VIC, Australia
| | - Yi-Hsun Chen
- Australian Research Council Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Clayton, 3800, VIC, Australia
- School of Physics and Astronomy, Monash University, Clayton, 3800, VIC, Australia
| | - Shao-Yu Chen
- Australian Research Council Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Clayton, 3800, VIC, Australia
- School of Physics and Astronomy, Monash University, Clayton, 3800, VIC, Australia
| | - Mark T Edmonds
- Australian Research Council Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Clayton, 3800, VIC, Australia
- School of Physics and Astronomy, Monash University, Clayton, 3800, VIC, Australia
- Monash Centre for Atomically Thin Materials, Monash University, Clayton, 3800, VIC, Australia
| | - Michael S Fuhrer
- Australian Research Council Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Clayton, 3800, VIC, Australia
- School of Physics and Astronomy, Monash University, Clayton, 3800, VIC, Australia
- Monash Centre for Atomically Thin Materials, Monash University, Clayton, 3800, VIC, Australia
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Yin H, Xing K, Zhang Y, Dissanayake DMAS, Lu Z, Zhao H, Zeng Z, Yun JH, Qi DC, Yin Z. Periodic nanostructures: preparation, properties and applications. Chem Soc Rev 2021; 50:6423-6482. [PMID: 34100047 DOI: 10.1039/d0cs01146k] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Periodic nanostructures, a group of nanomaterials consisting of single or multiple nano units/components periodically arranged into ordered patterns (e.g., vertical and lateral superlattices), have attracted tremendous attention in recent years due to their extraordinary physical and chemical properties that offer a huge potential for a multitude of applications in energy conversion, electronic and optoelectronic applications. Recent advances in the preparation strategies of periodic nanostructures, including self-assembly, epitaxy, and exfoliation, have paved the way to rationally modulate their ferroelectricity, superconductivity, band gap and many other physical and chemical properties. For example, the recent discovery of superconductivity observed in "magic-angle" graphene superlattices has sparked intensive studies in new ways, creating superlattices in twisted 2D materials. Recent development in the various state-of-the-art preparations of periodic nanostructures has created many new ideas and findings, warranting a timely review. In this review, we discuss the current advances of periodic nanostructures, including their preparation strategies, property modulations and various applications.
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Affiliation(s)
- Hang Yin
- Research School of Chemistry, Australian National University, ACT 2601, Australia.
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Zhang L, He X, Xing K, Zhang W, Tadich A, Wong PKJ, Qi DC, Wee ATS. Is Charge-Transfer Doping Possible at the Interfaces of Monolayer VSe 2 with MoO 3 and K? ACS Appl Mater Interfaces 2019; 11:43789-43795. [PMID: 31657202 DOI: 10.1021/acsami.9b16822] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Being a metallic transition-metal dichalcogenide, monolayer vanadium diselenide (VSe2) exhibits many novel properties, such as charge density waves and magnetism. Its interfaces with other materials can potentially be used in device applications as well as for manipulating its intrinsic properties. Here, we present a scanning tunneling microscopy and synchrotron-based X-ray photoemission spectroscopy study of the surface charge-transfer doping using efficient electron-withdrawing and electron-donating materials, that is, molybdenum trioxide (MoO3) and potassium (K), on the molecular beam epitaxy-grown monolayer VSe2 on highly oriented pyrolytic graphite (HOPG). We demonstrate that monolayer VSe2 is immune to MoO3- and K-doping effects. However, at the monolayer edges where the local chemical reactivity is higher because of Se deficiency, MoO3 is seen to react with VSe2 to form molybdenum dioxide (MoO2) and vanadium dioxide (VO2). Compared to the obvious charge-transfer doping effects of MoO3 and K on HOPG, the electronic structure of monolayer VSe2 is barely perturbed. This is attributed to the large density of states at the Fermi level of monolayer VSe2 carrying the metallic character. This work provides new insights into the chemical and electronic properties of monolayer VSe2, important for future VSe2-based electronic device design.
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Affiliation(s)
- Lei Zhang
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542 , Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre , National University of Singapore , 6 Science Drive 2 , Singapore 117546 , Singapore
| | - Xiaoyue He
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542 , Singapore
- Songshan Lake Materials Laboratory , Dongguan , Guangdong 523808 , China
| | - Kaijian Xing
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science , La Trobe University , Melbourne , Victoria 3086 , Australia
| | - Wen Zhang
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542 , Singapore
| | - Anton Tadich
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science , La Trobe University , Melbourne , Victoria 3086 , Australia
- Australian Synchrotron , 800 Blackburn Road , Clayton , Victoria 3168 , Australia
| | - Ping Kwan Johnny Wong
- Centre for Advanced 2D Materials and Graphene Research Centre , National University of Singapore , 6 Science Drive 2 , Singapore 117546 , Singapore
| | - Dong-Chen Qi
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science , La Trobe University , Melbourne , Victoria 3086 , Australia
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies, School of Chemistry, Physics and Mechanical Engineering , Queensland University of Technology , Brisbane , Queensland 4001 , Australia
| | - Andrew T S Wee
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542 , Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre , National University of Singapore , 6 Science Drive 2 , Singapore 117546 , Singapore
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8
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Xing K, Huang G, Hua S, Xu G, Li M. Systematic review of randomized controlled trials on antibiotic treatment for osteomyelitis in diabetes. Diabet Med 2019; 36:546-556. [PMID: 30785639 DOI: 10.1111/dme.13935] [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] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/18/2019] [Indexed: 12/28/2022]
Abstract
AIM To evaluate the efficacy of antibiotic therapy in osteomyelitis treatment among people with diabetes. METHODS A systematic search of PubMed, EMBASE, AMED, Web of Science, the WHO trial registry, Cochrane library databases, and ClinicalTrials.gov, in addition to hand-searching, was undertaken in July 2018. Two reviewers independently extracted data. The studies' methodological quality was assessed using the modified Jadad scale. Descriptive analysis was performed. RESULTS Seven randomized controlled trials, with 393 participants in total, were included. The antibiotic regimens, treatments and follow-up durations varied among the trials. The total scores showed that the overall methodological quality of the seven studies was high, despite two studies showing some flaws in double-blinding and withdrawals/drop-outs. Of four studies comparing different antibiotic regimens, three implied a similar remission effect, while one implied that ertapenem ± vancomycin treatment showed a higher remission rate than tigecycline treatment; this conclusion was not robust because of low power and small sample size. In the other three studies, which included two different doses of ciprofloxacin, an antibiotics group and a conservative surgical group, and two durations of the same antibiotic strategy, no significant differences in remission were reported between the groups. No difference was observed in the analyses of microbiological outcomes, superinfections and relapse, except adverse events. CONCLUSIONS There is no definitive evidence supporting the superiority of any particular antibiotic agent, dose, or administration duration in the treatment of osteomyelitis in diabetes. As the included studies had some flaws and limitations, further research is necessary.
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Affiliation(s)
- K Xing
- Department of Orthopaedic Oncology, Honghui Hospital, Xi'an Jiaotong University, College of Medicine, Xi'an, Shaanxi, China
| | - G Huang
- Department of Orthopaedic Oncology, Honghui Hospital, Xi'an Jiaotong University, College of Medicine, Xi'an, Shaanxi, China
| | - S Hua
- Department of Rheumatism and Immunity Branch, Xi an No. 5 Hospital, Xi'an, Shaanxi, China
| | - G Xu
- Department of Neurosurgery, First Affiliated Hospital of Xi'an Medical University, Xi'an, Shaanxi, China
| | - M Li
- Department of Paediatric Orthopedics, Honghui Hospital, Xi'an Jiaotong University, College of Medicine, Xi'an, Shaanxi, China
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Wang Y, Ding X, Tan Z, Xing K, Yang T, Wang Y, Sun D, Wang C. Genome-wide association study for reproductive traits in a Large White pig population. Anim Genet 2018; 49:127-131. [PMID: 29411893 PMCID: PMC5873431 DOI: 10.1111/age.12638] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [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] [Accepted: 11/27/2017] [Indexed: 11/27/2022]
Abstract
Using the PorcineSNP80 BeadChip, we performed a genome‐wide association study for seven reproductive traits, including total number born, number born alive, litter birth weight, average birth weight, gestation length, age at first service and age at first farrowing, in a population of 1207 Large White pigs. In total, we detected 12 genome‐wide significant and 41 suggestive significant SNPs associated with six reproductive traits. The proportion of phenotypic variance explained by all significant SNPs for each trait ranged from 4.46% (number born alive) to 11.49% (gestation length). Among them, 29 significant SNPs were located within known QTL regions for swine reproductive traits, such as corpus luteum number, stillborn number and litter size, of which one QTL region associated with litter size contained the ALGA0098819 SNP for total number born. Subsequently, we found that 376 functional genes contained or were near these significant SNPs. Of these, 14 genes—BHLHA15, OCM2, IL1B2, GCK, SMAD2, HABP2, PAQR5, GRB10, PRELID2, DMKN, GPI, GPIHBP1, ADCY2 and ACVR2B—were considered important candidates for swine reproductive traits based on their critical roles in embryonic development, energy metabolism and growth development. Our findings contribute to the understanding of the genetic mechanisms for reproductive traits and could have a positive effect on pig breeding programs.
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Affiliation(s)
- Y Wang
- Key Laboratory of Animal Genetics and Breeding of Ministry of Agriculture, National Engineering Laboratory of Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, 100094, China
| | - X Ding
- Key Laboratory of Animal Genetics and Breeding of Ministry of Agriculture, National Engineering Laboratory of Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, 100094, China
| | - Z Tan
- Key Laboratory of Animal Genetics and Breeding of Ministry of Agriculture, National Engineering Laboratory of Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, 100094, China
| | - K Xing
- Key Laboratory of Animal Genetics and Breeding of Ministry of Agriculture, National Engineering Laboratory of Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, 100094, China
| | - T Yang
- Key Laboratory of Animal Genetics and Breeding of Ministry of Agriculture, National Engineering Laboratory of Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, 100094, China
| | - Y Wang
- Beijing Shunxin Agriculture Co., Ltd., Beijing, 101300, China
| | - D Sun
- Key Laboratory of Animal Genetics and Breeding of Ministry of Agriculture, National Engineering Laboratory of Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, 100094, China
| | - C Wang
- Key Laboratory of Animal Genetics and Breeding of Ministry of Agriculture, National Engineering Laboratory of Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, 100094, China
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Xing K, Gao M, Li H. Genetic differentiation between natural and hatchery populations of Manila clam (Ruditapes philippinarum) based on microsatellite markers. Genet Mol Res 2014; 13:237-45. [DOI: 10.4238/2014.january.17.7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Abstract
Cladograms of iridoviruses were inferred from bootstrap analysis of molecular data sets comprising all published protein and DNA sequences of the major capsid protein, ATPase and DNA polymerase genes of members of the Iridoviridae family Iridovirus. All data sets yielded cladograms supporting the separation of the Iridovirus, Ranavirus and Lymphocystivirus genera, and the cladogram based on data derived from major capsid proteins further divided both the Iridovirus and Ranavirus genera into two groups. Tests of alternative hypotheses of topological constraints were also performed to further investigate relationships between infectious spleen and kidney necrosis virus (ISKNV), an unclassified fish iridovirus for which the complete genome sequence data is available, and other iridoviruses. Cladograms inferred and results of Shimodaira-Hasegawa tests indicated that ISKNV is more closely related to the Ranavirus genus than it is to the other genera of the family.
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Affiliation(s)
- J W Wang
- State Key Laboratory for Biocontrol, School of Life Science, Zhongshan University, Guangzhou, People's Republic of China
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12
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Ouyang J, Yang L, Long QX, Wang XZ, Xing K, Wei PH. [High level secretion expression of porcine somatoropin gene in Pichia pastoris and N-glycosylation analysis of products]. Sheng Wu Gong Cheng Xue Bao 2001; 17:520-5. [PMID: 11797213] [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: 02/23/2023]
Abstract
The porcine somatoropin gene was inserted into the Pichia pastoris expression vector of pPICZ alpha A which contains AOX I promoter and alpha-factor signal sequence. The recombinant plasmid of pPICZ alpha A-pST was linearnized by Sac I and transformed into X-33 by electroporation. The multi-copy insert transformants were selected and cultivated in flasks. SDS-PAGE and Western blot analysis showed that PST gene products were observed in the supernants with a little larger molecular weight size than the natural PST's, however, the molecular weight size of the PST gene products in the soluble cellular proteins were identical to the natural PST's. Retransformation of the linearnized pPICZ alpha-pST showed the expression level was improved greatly and rPST has the same antigenicity as natural one. The expressed rPST accumulated up to about 956 mg/L. The N-glycosylation analysis showed rPST had no N-glycosylation.
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Affiliation(s)
- J Ouyang
- State Key Laboratory for Biological Control, Biopharmaceutical Center, Zhongshan University, Guangzhou 510275, China
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13
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Raghavachari N, Krysan K, Xing K, Lou MF. Regulation of thioltransferase expression in human lens epithelial cells. Invest Ophthalmol Vis Sci 2001; 42:1002-8. [PMID: 11274078] [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: 02/19/2023] Open
Abstract
PURPOSE To study how the expression of thioltransferase (TTase), a critical thiol repair and dethiolating enzyme, is regulated in human lens epithelial cells under oxidative stress. Also to examine whether depleting the primary cellular antioxidant glutathione (GSH) in these cells has any influence on TTase expression under the same conditions. METHODS Human lens epithelial cells (B3) were grown to confluence (1.6 million) and gradually weaned from serum in the medium before exposing to 0.1 mM H2O2 for 2 hours. Cells were removed at the time intervals of 0, 5, 10, 15, 30, 60, and 120 minutes for protein measurements of GSH and TTase activity and for reverse transcription-polymerase chain reaction (RT-PCR) or Northern hybridization analysis to quantify TTase mRNA. The effect of GSH depletion on TTase mRNA expression was examined by treating the cells with buthionine S,R-sulfoximine (BSO); 1-chloro, 2,4-dinitrobenzene (CDNB); or 1,3-bis (2-chloroethyl)-1-nitrosourea (BCNU). Lens epithelial cells, depleted of cellular GSH by treatment with BCNU, were subjected to oxidative stress to examine the effect on TTase activity and mRNA level. RESULTS A transient increase was detected in TTase mRNA after 5 minutes of H2O2 treatment. The upregulation reached a maximum of 80% above the normal level by 10 minutes and gradually decreased as the oxidant was detoxified by the cells. Manipulation of cellular GSH level by treatment with BSO, CDNB, and BCNU resulted in a minimum change in TTase expression. It is noteworthy that when cells depleted of GSH were subjected to oxidative stress, TTase expression was also found to be strongly upregulated. CONCLUSIONS These observations suggest that the upregulation of TTase expression in the lens epithelial cells could be an adaptive response of the cells to combat oxidative stress to restore the vital functions of the lens proteins and enzymes. Such regulation is independent of cellular GSH concentration.
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Affiliation(s)
- N Raghavachari
- Department of Veterinary and Biomedical Sciences, University of Nebraska, Lincoln 68583-0905, USA
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Qiao F, Xing K, Liu A, Ehlers N, Raghavachari N, Lou MF. Human lens thioltransferase: cloning, purification, and function. Invest Ophthalmol Vis Sci 2001; 42:743-51. [PMID: 11222536] [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: 02/19/2023] Open
Abstract
PURPOSE To clone the human lens thioltransferase (TTase) gene and to purify, characterize and study the possible function of the recombinant human lens thioltransferase (RHLT). METHODS The human lens TTase gene was cloned by using RT-PCR and verified by sequence and RNase protection assay. TTase overexpressed in Escherichia coli was isolated and purified to homogeneity by column chromatography and identified by Western blot analysis. The activity was assayed with a synthetic substrate hydroxyethyl disulfide. Its function in dethiolating and reactivating other key metabolic enzymes was studied by using pure glutathione S:-transferase (GST) and glutathione peroxidase (GPx) from commercial source and also with the cell extract of rabbit lens epithelial cells preexposed to H2O2. RESULTS The cloned human lens TTase gene showed identical sequence to the TTase gene from other human tissues. The RNase protection assay displayed a single transcript from the total RNA of human lens epithelial cells. The purified RHLT had a molecular weight of 11.8 kDa and reacted positively with anti-pig liver TTase. It displayed similar structural, functional, and kinetic characteristics to those of TTases from other sources. It was shown that RHLT effectively regenerated the activities of GST and GPx, after each was inactivated by S-thiolation with cystine in vitro. Furthermore, RHLT was able to restore the activity of the oxidatively inactivated glyceraldehyde-3-phosphate dehydrogenase (G-3PD) in H2O2-exposed rabbit lens epithelial cells. CONCLUSIONS The human lens TTase gene has been cloned for the first time. Its gene product showed the characteristics which support our speculation that TTase may play a major role in maintaining the homeostasis of lens protein thiols thus protecting against oxidative stress.
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Affiliation(s)
- F Qiao
- Department of Veterinary and Biomedical Sciences, University of Nebraska-Lincoln, 134 VBS, Lincoln, NE 68583-0905, USA
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Abstract
The observation that the level of S-thiolated proteins (protein-thiol mixed disulfides) was transiently increased in the lens epithelial cells correlation with the transient inactivation of glyceraldehyde-3-phosphate dehydrogenase (G-3PD), a key glycolytic enzyme, when the cells were treated with a bolus of hydrogen peroxide, prompted our speculation that G-3PD may have been transiently thiolated at the SH sensitive active center. In the meantime, thioltransferase (TTase), a thiol regulating enzyme, whose activity remained constant under the same condition, may be regulating G-3PD and other sulfhydryl-sensitive glycolytic enzymes through thiol-disulfide exchange reactions ( Lou et al., 1998 ). To prove this hypothesis, several purified glycolytic enzymes from a commercial source, including hexokinase (HK), G-3PD, pyruvate kinase (PK) and fructose 1,6-bisphosphatase (FBPase), an enzyme in gluconeogenesis, were made into protein-thiol mixed disulfide and used for this study. Glycolytic enzymes in cultured rabbit lens epithelial cells pre-exposed to H(2)O(2)(0.5 m M for 15 min) were also studied for this purpose. Recombinant human lens thioltransferase (RHLT), which was isolated and purified previously in this laboratory, reactivated these pure glycolytic enzymes inactivated by forming protein-S-S-gluthathione (PSSG), protein-S-S-cysteine (PSSC) or, protein-S-S-cysteamine after thiolating with oxidized glutathione, cystine or cystamine respectively. RHLT also reactivated these enzymes in the cell extract of cultured rabbit lens epithelial cells after being briefly exposed to 0.5 m M H(2)O(2). The S-thiolation and dethiolation of FBPase however, showed an opposite effect to that of glycolytic enzymes. These results suggest that TTase may participate in the repair process of glycolytic enzymes during oxidative stress and restore their activities in situ.
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Affiliation(s)
- F Qiao
- Center for Biotechnology and Department of Veterinary and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA
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Malmsten M, Xing K, Ljunglöf A. Confocal Microscopy Studies of Trypsin Immobilization on Porous Glycidyl Methacrylate Beads. J Colloid Interface Sci 1999; 220:436-442. [PMID: 10607463 DOI: 10.1006/jcis.1999.6540] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The immobilization of trypsin on porous glycidyl methacrylate (GMA-GDMA) beads has been investigated. In particular, the distribution within the beads of trypsin and of dextran used for hydrophilizing the bead surface prior to protein immobilization was investigated with confocal microscopy. For the system investigated, the fluorescence intensity profiles obtained when using borate buffer as an ambient solution displayed a distinct minimum at the center of the beads, irrespective of the observation depth. However, by reduction of the refractive index difference between the solution and the beads through the addition of glucose to the aqueous solution, artifacts relating to optical length differences could be reduced. For both low molecular weight fluorescein isothiocyanate (FITC), FITC-labeled trypsin, and FITC-labeled dextran, an essentially homogeneous distribution throughout the beads was observed. This simple "contrast matching" method seems therefore to be an interesting tool when investigating the distribution of immobilized protein in porous chromatography media. Copyright 1999 Academic Press.
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Affiliation(s)
- M Malmsten
- Institute for Surface Chemistry, Stockholm, SE-114 86, Sweden
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Wang Y, Xing K. X-ray diffraction of interfaces in nanocrystals. Acta Crystallogr A 1996. [DOI: 10.1107/s0108767396076234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Iucci G, Xing K, Lögdlund M, Fahlman M, Salaneck W. Polaron to bipolaron transition in a conjugated polymer. Rubidium-doped poly(p-phenylenevinylene). Chem Phys Lett 1995. [DOI: 10.1016/0009-2614(95)00921-p] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Fahlman M, Bröms P, dos Santos DA, Moratti SC, Johansson N, Xing K, Friend RH, Holmes AB, Brédas JL, Salaneck WR. Electronic structure of pristine and sodium‐doped cyano‐substituted poly(2,5‐dihexyloxy‐p‐phenylenevinylene): A combined experimental and theoretical study. J Chem Phys 1995. [DOI: 10.1063/1.469228] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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