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Chu JH, Xiong J, Wong CTT, Wang S, Tam DY, García-Fernández A, Martínez-Máñez R, Ng DKP. Detection and Elimination of Senescent Cells with a Self-Assembled Senescence-Associated β-Galactosidase-Activatable Nanophotosensitizer. J Med Chem 2024; 67:234-244. [PMID: 38113190 PMCID: PMC10788907 DOI: 10.1021/acs.jmedchem.3c01306] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 11/28/2023] [Accepted: 11/29/2023] [Indexed: 12/21/2023]
Abstract
Senescent cells have become an important therapeutic target for many age-related dysfunctions and diseases. We report herein a novel nanophotosensitizing system that is responsive to the senescence-associated β-galactosidase (β-gal) for selective detection and elimination of these cells. It involves a dimeric zinc(II) phthalocyanine linked to a β-galactose unit via a self-immolative linker. This compound can self-assemble in aqueous media, forming stable nanoscale particles in which the phthalocyanine units are stacked and self-quenched for fluorescence emission and singlet oxygen production. Upon internalization into senescent HeLa cells, these nanoparticles interact with the overproduced senescence-associated β-gal inside the cells to trigger the disassembly process through enzymatic cleavage of the glycosidic bonds, followed by self-immolation to release the photoactive monomeric phthalocyanine units. These senescent cells can then be lit up with fluorescence and eliminated through the photodynamic action upon light irradiation with a half-maximal inhibitory concentration of 0.06 μM.
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Affiliation(s)
- Jacky
C. H. Chu
- Department
of Chemistry, The Chinese University of
Hong Kong, Shatin, N.T., Hong Kong, China
| | - Junlong Xiong
- Department
of Chemistry, The Chinese University of
Hong Kong, Shatin, N.T., Hong Kong, China
- Department
of Pharmacy, The Affiliated Luohu Hospital
of Shenzhen University, Shenzhen University, Shenzhen 518001, China
| | - Clarence T. T. Wong
- Department
of Chemistry, The Chinese University of
Hong Kong, Shatin, N.T., Hong Kong, China
- Department
of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
| | - Shuai Wang
- Department
of Chemistry, The Chinese University of
Hong Kong, Shatin, N.T., Hong Kong, China
| | - Dick Yan Tam
- Department
of Chemistry, The Chinese University of
Hong Kong, Shatin, N.T., Hong Kong, China
| | - Alba García-Fernández
- Instituto
Interuniversitario de Investigación de Reconocimiento, Molecular
y Desarrollo Tecnológico, Universitat
Politècnica de València, Universitat de València, Valencia46022, Spain
- CIBER
de Bioingeniería, Biomateriales y Nanomedicina, Instituto de Salud Carlos III, Madrid 28029, Spain
- Unidad Mixta
UPV-CIPF de Investigación en Mecanismos de Enfermedades y Nanomedicina,
Centro de Investigación Príncipe Felipe, Universitat Politècnica de València, Valencia46012, Spain
| | - Ramón Martínez-Máñez
- Instituto
Interuniversitario de Investigación de Reconocimiento, Molecular
y Desarrollo Tecnológico, Universitat
Politècnica de València, Universitat de València, Valencia46022, Spain
- CIBER
de Bioingeniería, Biomateriales y Nanomedicina, Instituto de Salud Carlos III, Madrid 28029, Spain
- Unidad Mixta
UPV-CIPF de Investigación en Mecanismos de Enfermedades y Nanomedicina,
Centro de Investigación Príncipe Felipe, Universitat Politècnica de València, Valencia46012, Spain
- Unidad
Mixta de Investigación en Nanomedicina y Sensores, Instituto
de Investigación Sanitaria La Fe (IIS La Fe), Universitat Politècnica e València, Valencia 46026, Spain
| | - Dennis K. P. Ng
- Department
of Chemistry, The Chinese University of
Hong Kong, Shatin, N.T., Hong Kong, China
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Gao YQ, Xu CL, Fu HY, Zhu TT, Chu JH. [Clinical significance and pathogenesis analysis of Moesin in multiple myeloma]. Zhonghua Xue Ye Xue Za Zhi 2023; 44:672-675. [PMID: 37803842 PMCID: PMC10520239 DOI: 10.3760/cma.j.issn.0253-2727.2023.08.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Indexed: 10/08/2023]
Affiliation(s)
- Y Q Gao
- Institute of Blood and Marrow Transplantation, Medical College of Soochow University, National Clinical Research Center for Hematologic Diseases, The First Affiliated Hospital of Soochow University, Jiangsu Institute of Hematology, Collaborative Innovation Center of Hematology, Suzhou 215000, China Children's Hospital of Soochow University, Suzhou 215000, China
| | - C L Xu
- Department of Clinical Laboratory, Dongtai Municipal People's Hospital, Dongtai 224200, China
| | - H Y Fu
- Children's Hospital of Soochow University, Suzhou 215000, China
| | - T T Zhu
- Institute of Blood and Marrow Transplantation, Medical College of Soochow University, National Clinical Research Center for Hematologic Diseases, The First Affiliated Hospital of Soochow University, Jiangsu Institute of Hematology, Collaborative Innovation Center of Hematology, Suzhou 215000, China
| | - J H Chu
- Institute of Blood and Marrow Transplantation, Medical College of Soochow University, National Clinical Research Center for Hematologic Diseases, The First Affiliated Hospital of Soochow University, Jiangsu Institute of Hematology, Collaborative Innovation Center of Hematology, Suzhou 215000, China
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Zhang AA, Tang JY, Xu M, Fang YJ, Yan J, Gao J, Yuan XJ, Li F, Ju XL, Liu W, Wu XJ, Sun LR, Jiang L, Zhang WL, Chu JH, Lu XY. [Multicenter clinical study on the diagnosis and treatment of childhood renal tumor]. Zhonghua Er Ke Za Zhi 2021; 59:195-200. [PMID: 33657693 DOI: 10.3760/cma.j.cn112140-20200707-00698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Objective: To summarize the effect of Chinese Children's Cancer Group (CCCG) Wilms tumor (WT)-2015 protocol. Methods: This was a prospective study. CCCG-WT-2015 protocol was revised on the basis of the CCCG-WT-2009 protocol. Clinical data of 288 children diagnosed with newly diagnosed kidney neoplasms in fourteen pediatric centers between September 2015 to December 2018 were summarized. The age of onset, distribution of pathological subtypes, staging, curative effect and prognostic factors of these children were analyzed. Kaplan-Meier method was used for survival curve and Log-Rank method was used for univariate analysis. Results: Among 288 cases with kidney neoplasms, there were 261 cases of WT, including 254 cases (97.3%) with favorable histology (FH) WT and 7 cases (2.7%) with unfavorable histology WT (UFHWT). The 3 year events free survival (EFS) rate for FHWT and UFHWT were (88.9±2.1)% and (80.0±17.9)%, which were better than that in WT-2009 (81.2% and 71.7%). In the 96 cases of stage Ⅲ/Ⅳ FHWT with indications for radiotherapy, 76 cases received radiation, another 20 cases received M protocol chemotherapy (cyclophosphamide, etoposide, gentamycin, vincristine and adriamycin) instead of radiation. The 3 year EFS rate for these two groups were (84.7±4.3)% and (84.7±8.1)%(χ2=0.015, P=0.902). There were 22 renal clear cell sarcoma and 5 malignant rhabdoid tumor, 3 year EFS rate of them was (94.4±5.4)% and (20.0±17.9)%. Univariate analysis was performed for age, gender, pathological type, stage, whether rupture occurred during operation, whether complete remission (CR) occurred at the end of treatment and radiotherapy. Pathological types (χ2=44.329,P<0.01) and failure to achieve CR at the end of the treatment (χ2=49.459,P<0.01) were independent factor for predicting survival. Conclusion: Compared with CCCG-WT-2009, treatment of renal tumors in CCCG-WT-2015 study yielded good survival outcome, which can be further applied.
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Affiliation(s)
- A A Zhang
- Department of Hematology and Oncology, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
| | - J Y Tang
- Department of Hematology and Oncology, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
| | - M Xu
- Department of Oncology Surgery, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
| | - Y J Fang
- Department of Hematology and Oncology, Children's Hospital of Nanjing Medical University,Nanjing 210008, China
| | - J Yan
- Department of Oncology, Tianjin Medical University Cancer Hospital,Tianjin 300020, China
| | - J Gao
- Department of Hematology and Oncology, West China Second University Hospital, Sichuan University, Chengdu 610041, China
| | - X J Yuan
- Department of Pediatric Hematology and Oncology, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - F Li
- Department of Hematology and Oncology, Qilu Children's Hospital of Shandong University, Jinan 250022, China
| | - X L Ju
- Department of Pediatrics, Qilu Hospital of Shandong University, Jinan 250012, China
| | - W Liu
- Department of Hematology and Oncology, Henan Children's Hospital,Zhengzhou 450018, China
| | - X J Wu
- Department of Pediatric Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430032, China
| | - L R Sun
- Department of Pediatrics, the Affiliated Hospital of Qingdao University, Qingdao 266555, China
| | - L Jiang
- Department of Pediatrics, the Fourth Hospital of Hebei Medical University,Shijiazhuang 050000, China
| | - W L Zhang
- Department of Pediatric Hematology and Oncology,the Affiliated Hospital of Zhengzhou University, Zhengzhou 450008, China
| | - J H Chu
- Department of Pediatrics, the Second Hospital of Anhui Medical University,Hefei 230601, China
| | - X Y Lu
- Department of Oncology Surgery, Children's Hospital of Anhui Medical University, Hefei 230022, China
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Cong WT, Tang Z, Zhao XG, Chu JH. Enhanced magnetic anisotropies of single transition-metal adatoms on a defective MoS2 monolayer. Sci Rep 2015; 5:9361. [PMID: 25797135 PMCID: PMC4369737 DOI: 10.1038/srep09361] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [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: 01/27/2014] [Accepted: 03/02/2015] [Indexed: 11/10/2022] Open
Abstract
Single magnetic atoms absorbed on an atomically thin layer represent the ultimate limit of bit miniaturization for data storage. To approach the limit, a critical step is to find an appropriate material system with high chemical stability and large magnetic anisotropic energy. Here, on the basis of first-principles calculations and the spin-orbit coupling theory, it is elucidated that the transition-metal Mn and Fe atoms absorbed on disulfur vacancies of MoS2 monolayers are very promising candidates. It is analysed that these absorption systems are of not only high chemical stabilities but also much enhanced magnetic anisotropies and particularly the easy magnetization axis is changed from the in-plane one for Mn to the out-of-plane one for Fe by a symmetry-lowering Jahn-Teller distortion. The results point out a promising direction to achieve the ultimate goal of single adatomic magnets with utilizing the defective atomically thin layers.
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Affiliation(s)
- W T Cong
- Key Laboratory of Polar Materials and Devices, Ministry of Education of China, East China Normal University, Shanghai 200241, People's Republic of China
| | - Z Tang
- Key Laboratory of Polar Materials and Devices, Ministry of Education of China, East China Normal University, Shanghai 200241, People's Republic of China
| | - X G Zhao
- Key Laboratory of Polar Materials and Devices, Ministry of Education of China, East China Normal University, Shanghai 200241, People's Republic of China
| | - J H Chu
- Key Laboratory of Polar Materials and Devices, Ministry of Education of China, East China Normal University, Shanghai 200241, People's Republic of China
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Fina I, Marti X, Yi D, Liu J, Chu JH, Rayan-Serrao C, Suresha S, Shick AB, Zelezný J, Jungwirth T, Fontcuberta J, Ramesh R. Anisotropic magnetoresistance in an antiferromagnetic semiconductor. Nat Commun 2014; 5:4671. [PMID: 25204755 DOI: 10.1038/ncomms5671] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 07/11/2014] [Indexed: 11/09/2022] Open
Abstract
Recent studies in devices comprising metal antiferromagnets have demonstrated the feasibility of a novel spintronic concept in which spin-dependent phenomena are governed by an antiferromagnet instead of a ferromagnet. Here we report experimental observation of the anisotropic magnetoresistance in an antiferromagnetic semiconductor Sr2IrO4. Based on ab initio calculations, we associate the origin of the phenomenon with large anisotropies in the relativistic electronic structure. The antiferromagnet film is exchange coupled to a ferromagnet, which allows us to reorient the antiferromagnet spin-axis in applied magnetic fields via the exchange spring effect. We demonstrate that the semiconducting nature of our AFM electrode allows us to perform anisotropic magnetoresistance measurements in the current-perpendicular-to-plane geometry without introducing a tunnel barrier into the stack. Temperature-dependent measurements of the resistance and anisotropic magnetoresistance highlight the large, entangled tunabilities of the ordinary charge and spin-dependent transport in a spintronic device utilizing the antiferromagnet semiconductor.
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Affiliation(s)
- I Fina
- 1] Institut de Ciència de Materials de Barcelona, ICMAB-CSIC, Campus UAB, E-08193 Barcelona, Spain [2] Experimental Department II, Max Planck Institute of Microstructure Physics, Weinberg 2, D-06120 Halle, Germany
| | - X Marti
- 1] Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA [2] Centre d'Investigació en Nanociència i Nanotecnologia (CIN2), CSIC-ICN, 08193 Barcelona, Spain [3] Department of Spintronics and Nanoelectronics, Institute of Physics ASCR, v.v.i., Cukrovarnická 10, 162 53 Praha 6, Czech Republic
| | - D Yi
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
| | - J Liu
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - J H Chu
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - C Rayan-Serrao
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
| | - S Suresha
- National Center for Electron Microscopy, Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - A B Shick
- Department of Condensed Matter Theory, Institute of Physics ASCR, v.v.i., Na Slovance 2, 182 21 Praha 8, Czech Republic
| | - J Zelezný
- Department of Spintronics and Nanoelectronics, Institute of Physics ASCR, v.v.i., Cukrovarnická 10, 162 53 Praha 6, Czech Republic
| | - T Jungwirth
- 1] Department of Spintronics and Nanoelectronics, Institute of Physics ASCR, v.v.i., Cukrovarnická 10, 162 53 Praha 6, Czech Republic [2] School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
| | - J Fontcuberta
- Institut de Ciència de Materials de Barcelona, ICMAB-CSIC, Campus UAB, E-08193 Barcelona, Spain
| | - R Ramesh
- 1] Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA [2] Department of Physics, University of California, Berkeley, California 94720, USA [3] National Center for Electron Microscopy, Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA [4]
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6
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Zhang XL, Zhu JJ, Zhang JZ, Xu GS, Hu ZG, Chu JH. Photoluminescence study on polar nanoregions and structural variations in Pb(Mg₁/₃Nb₂/₃)O₃ ₋ PbTiO₃ single crystals. Opt Express 2014; 22:21903-21911. [PMID: 25321565 DOI: 10.1364/oe.22.021903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report polar nanostructure and electronic transitions in relaxor ferroelectric Pb(Mg₁/₃Nb₂/₃)O₃ ₋ PbTiO (PMN-PT) single crystals around morphotropic phase boundary (MPB) region by variable-temperature (80-800 K) photoluminescence (PL) spectra and low-wavenumber Raman scattering (LWRS). The discontinuous evolution from peak positions and intensity of luminescence emissions can be corresponding to formation of polar nanoclusters and phase transitions. Six emissions have been derived from PL spectra and show obvious characteristics near phase transition temperatures, which indicates that PL spectral measurement is promising in understanding the microcosmic mechanism. The Raman mode at 1145 cm(-1) indicates that temperature dependent luminescence phenomena can be modulated by thermal quenching.
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Tang Z, Sun F, Han B, Yu K, Zhu ZQ, Chu JH. Tuning interlayer exchange coupling of co-doped TiO2/VO2 multilayers via metal-insulator transition. Phys Rev Lett 2013; 111:107203. [PMID: 25166705 DOI: 10.1103/physrevlett.111.107203] [Citation(s) in RCA: 2] [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: 07/24/2013] [Indexed: 06/03/2023]
Abstract
Reversibly switching interlayer exchange coupling (IEC) of magnetic semiconductor multilayers between ferromagnetic (FM) and antiferromagnetic (AFM) modes is a difficult but key issue for fabricating semiconductor giant magnetoresistance devices. Here, we show that such tunable IEC is achievable around room temperature in Co-doped TiO2/VO2 diluted magnetic semiconductor multilayers. On the basis of first-principles calculations of electronic structure and fermiology, it is clarified that, associated with the metal-insulator transition (MIT) of nanosized VO2 spacers, exotic short-range magnetic orders are developed in the multilayers so that the IEC can be tuned reversibly from FM mode to AFM mode by varying temperature crossing the MIT (∼340 K).
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Affiliation(s)
- Z Tang
- Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai 200241, People's Republic of China
| | - F Sun
- Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai 200241, People's Republic of China
| | - B Han
- Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai 200241, People's Republic of China
| | - K Yu
- Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai 200241, People's Republic of China
| | - Z Q Zhu
- Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai 200241, People's Republic of China
| | - J H Chu
- Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai 200241, People's Republic of China
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Jiang K, Zhu JJ, Wu JD, Sun J, Hu ZG, Chu JH. Influences of oxygen pressure on optical properties and interband electronic transitions in multiferroic bismuth ferrite nanocrystalline films grown by pulsed laser deposition. ACS Appl Mater Interfaces 2011; 3:4844-4852. [PMID: 22103473 DOI: 10.1021/am201340d] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Bismuth ferrite (BiFeO(3)) nanocrystalline films with the crystalline size of 27-40 nm have been grown on c-sapphire substrates under various oxygen pressures of 1 × 10(-4) to 1 Pa by pulsed laser deposition. The X-ray diffraction spectra show that the films are polycrystalline and present the pure rhombohedral phase. It was found that the Raman-active phonon mode E(TO1) shifts towards a higher energy side from 74 to 76 cm(-1) with increasing oxygen pressure, indicating a larger tensile stress in the films deposited at higher oxygen pressure. The X-ray photoelectron spectroscopy analysis suggests that the concentrations of both Fe(2+) ions and oxygen vacancies in the BiFeO(3) films increase with decreasing oxygen pressure. Moreover, the dielectric functions in the photon energy range of 0.47-6.5 eV have been extracted by fitting the transmittance spectra with the Tauc-Lorentz dispersion model. From the transmittance spectra, the fundamental absorption edge is observed to present a redshift trend with increasing the temperature from 8 to 300 K. Note that the optical band gap (E(g)) decreases with increasing the temperature due to the electron-phonon interactions associated with the interatomic distance in the BiFeO(3) films. However, the E(g) decreases from 2.88 to 2.78 eV with decreasing oxygen pressure at 8 K, which can be attributed to the increment of oxygen vacancies leading to the formation of some impurity states between the valence and conduction band. It can be concluded that the oxygen pressure during the film fabrication has the significant effects on microstructure, optical properties, and electronic band structure modification of the BiFeO(3) films.
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Affiliation(s)
- K Jiang
- Key Laboratory of Polar Materials and Devices, Ministry of Education, Department of Electronic Engineering, East China Normal University, Shanghai 200241, People's Republic of China
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Gong SJ, Sheng W, Yang ZQ, Chu JH. First-principles investigation of bilayer graphene with intercalated C, N or O atoms. J Phys Condens Matter 2010; 22:245502. [PMID: 21393783 DOI: 10.1088/0953-8984/22/24/245502] [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] [Indexed: 05/30/2023]
Abstract
We apply first-principles calculations to investigate the structural, electronic and magnetic properties of the bilayer graphene, into which C, N or O atoms are intercalated. The inserted atoms initially set at the middle of the bilayer interval will finally be adsorbed to one graphene layer, resulting in the difference of electrostatic potential between the two graphene layers and then an opening of the energy gap filled with impurity states. Extended or quasilocalized states around the Fermi level introduced by the intercalated atoms induce the itinerant Stoner magnetism in C- and N-intercalated systems. The magnetic moment in the N-intercalated system is mainly contributed by the N atom, while in the C-intercalated system, besides the foreign intercalated C atom, host carbon atoms of the bilayer graphene also become magnetic, with the magnetization distribution showing threefold symmetry. Also, charge transfer from bilayer graphene to the intercalated N or O atoms results in the Fermi level shifting downward to the valence band and then the metallic behavior of the system.
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Affiliation(s)
- S J Gong
- National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, People's Republic of China.
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Li WW, Hu ZG, Li YW, Zhu M, Zhu ZQ, Chu JH. Growth, microstructure, and infrared-ultraviolet optical conductivity of La(0.5)Sr(0.5)CoO(3) nanocrystalline films on silicon substrates by pulsed laser deposition. ACS Appl Mater Interfaces 2010; 2:896-902. [PMID: 20356296 DOI: 10.1021/am900868a] [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: 05/29/2023]
Abstract
La(0.5)Sr(0.5)CoO(3) (LSCO) nanocrystalline (nc) films have been directly grown on silicon wafers under different substrate temperatures by pulsed laser deposition. The X-ray diffraction analysis indicate that the films are polycrystalline with the pure perovskite phase at higher substrate temperatures. The columnar growth formation with the nanocrystalline structure in the films has been confirmed by microscopy experiments. Infrared-ultraviolet optical properties of the LSCO films have been investigated with the aid of spectroscopic ellipsometry (SE). Dielectric function in the photon energy range of 1.1-3.1 eV (400-1100 nm) has been extracted by reproducing the experimental data with a Lorentz oscillator model. It is found that the real part is decreased from 4.7 to -0.7 at the near-infrared region with increasing substrate temperature. The optical conductivity shows a different variation trend for the lower and higher growth temperatures, respectively. Note that the films deposited above 650 degrees C exhibit the well-defined metallic phase behavior. The discrepancies could be mainly ascribed to different crystalline structure and surface morphology. The present results may be crucial for future applications of ferromagnetic-based optoelectronic and spin-electronic devices.
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Affiliation(s)
- W W Li
- Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai 200241, People's Republic of China
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Affiliation(s)
- M L Ng
- Department of Microbiology, 5 Science Drive 2, National University of Singapore, 11759 Singapore
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Yin XJ, Liu JZ, Kong XH, Chu JH, Wang H, Xiao ZX. Mutagenicity of urine from individuals exposed to LPG combustion products. Biomed Environ Sci 1998; 11:251-257. [PMID: 9861484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The mutagenicity of urine from individuals exposed to the combustion products of liquefied petroleum gas (LPG) was detected with Salmonella typhimurium TA98 and its newly developed derivatives YG1021 (nitroreductase overproducing) and YG1024 (O-acetyltransferase overproducing). The detection showed significantly increased mutagenicity for the two YG strains and increased positive rates for all three strains in the presence of both rat liver S9 and beta-glucuronidase. Further analysis demonstrated that urine samples taken from smoking and non-smoking exposed individuals exhibited significantly higher mutagenic potency (revertants/10 microliters urine concentrate) than their corresponding controls. These results indicate that the increased urine mutagenicity is caused by the exposure to LPG combustion products or smoking. The mutagenic potency of urine samples of all exposed individuals tested with YG1024 was found to be about 7 times higher than with TA98. The difference in mutagenic potency was smaller for the same samples when comparison was made between YG1021 and TA98. This suggests that the mutagenic compounds present in the urine samples contain mainly aromatic compounds as glucuronide conjugates. Our results demonstrate that YG1024 is more sensitive than TA98 in detecting the mutagenicity of these samples. In addition, no significant difference in the mutagenic potency between the 'pure' exposed (non-smokers') and the 'pure' smokers' (unexposed) samples was found in all three tester strains. This might mean that the exposure extent of mutagens/carcinogens in LPG combustion products for exposed individuals roughly corresponds to the smoking level of smokers who smoke 20-40 cigarettes per day. Furthermore, the results also suggest that synergism might exist in the mutagenic effects of exposure to LPG combustion products and cigarette smoking.
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Affiliation(s)
- X J Yin
- Institute of Occupational Medicine, Chinese Academy of Preventive Medicine, Beijing, China
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Abstract
The microscopic particle motions from the crystal to the disordered state of a dusty plasma with micrometer-sized silicon dioxide particle suspensions in a radio-frequency glow discharge system were studied through an optical microimaging system. Small-amplitude random motion around the lattice sites of the crystal state, relative domain motion with varying boundaries, cooperative hopping in the liquid state, and highly disordered motion with increasing radio-frequency power were observed. Chaotic states with different spatial scales under the coherent and stochastic coupling between dust particles and self-organized background plasma fluctuations were also demonstrated.
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Affiliation(s)
- L I
- Department of Physics, National Central University, Chungli, Taiwan 32054, Republic of China
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Affiliation(s)
- B T Kim
- Department of Chemistry, Seoul National University, Korea
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Chu JH, Mi ZY, Sizmann R, Koch F. Subband structure in the electric quantum limit for Hg1-xCdxTe. Phys Rev B Condens Matter 1991; 44:1717-1723. [PMID: 9999705 DOI: 10.1103/physrevb.44.1717] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Chu JH, I L. Quasiperiodic transition to spatiotemporal chaos in weakly ionized magnetoplasmas. Phys Rev A Gen Phys 1989; 39:233-238. [PMID: 9901007 DOI: 10.1103/physreva.39.233] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Abstract
A rapid urea-phenylalanine medium was effective for the identification of Proteus and, with one exception, Providencia. Most Klebsiella and a few Enterobacter were urease-positive with this method.
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Chu JH, Fang SD. The alkaloids of the Chinese drug, Aconitum spp. Alkaloids from xue-shang-yi-zhi-hao var. homotrichum W. T. Wang Aconitum bullatifolium Lévl. Sci Sin 1965; 14:1764-71. [PMID: 5881571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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