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Chen BJ, Xie XY, Ni LJ, Dai XL, Lu Y, Wu XQ, Li HY, Yao YD, Huang SY. Factors associated with Staphylococcus aureus nasal carriage and molecular characteristics among the general population at a Medical College Campus in Guangzhou, South China. Ann Clin Microbiol Antimicrob 2017; 16:28. [PMID: 28399856 PMCID: PMC5387264 DOI: 10.1186/s12941-017-0206-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [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: 01/28/2017] [Accepted: 04/06/2017] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND The nasal cavity is the main colonization site of Staphylococcus aureus (S. aureus) in human body. Nasal carriage may be a strong risk factor for some serious infection. There was still limited information about the nasal carriage for S. aureus in south China. METHODS Sought to determine the prevalence and molecular characteristics of S. aureus nasal carriage, 295 volunteers residing on a medicine campus were investigated and sampled the nasal cavity swab. Selected S. aureus isolates were carried through molecular analysis, including pulsed-field gel electrophoresis (PFGE), multilocus sequence analysis, staphylococcal cassette chromosome mec (SCCmec) and virulence gene detection. RESULTS A total of 73 S. aureus isolates were recovered from separate subjects (24.7%, 73/295), with one methicillin-resistant S. aureus (MRSA) isolate (0.3%, 1/295). Among the 73 isolates, 71 isolates were successfully grouped into 13 pulsotypes by PFGE analysis, with profiles A and L the most prevalent; 12 sequence types (STs) were found among the 23 isolates which had similar drug resistant spectrum. ST59, ST188 and ST1 were the most prevalent, accounting for 17.4, 13.0 and 13.0% of all isolates, respectively. The MRSA isolate presented ST8-SCCmec III. 56.5% of isolates carried both the staphylococcal enterotoxin A (sea) and enterotoxin B (seb) genes. 83.6% of the S. aureus isolates were resistant to penicillin, all isolates were susceptible to quinupristin/dalfopristin, levofloxacin, teicoplanin and vancomycin. The most common risk factors for S. aureus carriage were being male, age ≤30 years, and nasal cavity cleaning habits. CONCLUSIONS Colonization by S. aureus was greater among male and young age (20-30 years) students and those with irregularity nasal cleaning. The S. aureus isolates selected were revealed into various sequence types and pulsotypes, indicating molecular heterogeneity among S. aureus isolates from the populations in the medical college in Guangzhou.
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Affiliation(s)
- B J Chen
- Department of Laboratory, Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - X Y Xie
- Department of Laboratory, Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - L J Ni
- Department of Laboratory, Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - X L Dai
- Department of Laboratory, Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - Y Lu
- Cross Infection Control Office, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China
| | - X Q Wu
- Department of Laboratory, Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - H Y Li
- Department of Laboratory, Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - Y D Yao
- Breast Tumor Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China.
| | - S Y Huang
- Department of Laboratory, Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China.
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Ma Q, Yao YD, Hou XX, Wang MC, Wei ZG, Tian JH, Zhang YC, He XD. [The efficiency of different biliary cannulation in endoscopic retrograde cholangiopancreatography: a meta-analysis]. Zhonghua Nei Ke Za Zhi 2016; 55:863-868. [PMID: 27801342 DOI: 10.3760/cma.j.issn.0578-1426.2016.11.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Objective: To compare the success rates of wire-guided biliary cannulation (WGC) and conventional cannulation (CC) and their effect on the outcome of post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP). Methods: All randomized controlled trials (RCTs) were collected by searching CNKI, WanFang Data, CBM, PubMed, Embase and Cochrane Library.The assessment of methodological quality and data extraction of the included studies were performed independently by two reviewers. Meta-analysis was conducted with RevMan 5.2 software. Results: Ten RCTs, with a total of 3 262 patients enrolled, were retrieved.Meta-analysis demonstrated that WGC had a higher success rate(RR=1.04, 95%CI 1.01-1.06, P<0.01)and a lower risk of PEP after cannulation (RR=0.54, 95%CI 0.41-0.71, P<0.01). The main reason for the lower risk of PEP was due to lower proportion of mild PEP patients after WGC(RR=0.52, 95%CI 0.36-0.73, P<0.01), while the incidence of modest and severe PEP was comparable in the two groups(modest group: RR=0.84, 95%CI 0.43-1.64, P=0.61; severe group: RR=0.53, 95%CI 0.22-1.31, P=0.17). Conclusion: WGC may increase the success rate of cannulation and reduce the incidence of PEP because of less complications of mild PEP.
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Affiliation(s)
| | | | | | | | | | | | | | - X D He
- Department of General Surgery, Second Hospital of Lanzhou University, Evidence-based Medicine Center of Lanzhou University, Lanzhou 730030, China
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Abstract
This work demonstrates the controllability of the physical characteristics of NiFe/ZnO heterostructures which provide valuable multifunctional behaviors for potential novel magnetoelectric applications.
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Affiliation(s)
- P. W. Chi
- Institute of Manufacturing Technology and Department of Mechanical Engineering
- National Taipei University of Technology (TAIPEI TECH)
- Taipei 10608
- Taiwan
| | - D. H. Wei
- Institute of Manufacturing Technology and Department of Mechanical Engineering
- National Taipei University of Technology (TAIPEI TECH)
- Taipei 10608
- Taiwan
| | - S. H. Wu
- Research Center for Applied Sciences
- Academia Sinica
- Taipei 11529
- Taiwan
| | - Y. Y. Chen
- Institute of Physics
- Academia Sinica
- Taipei 11529
- Taiwan
| | - Y. D. Yao
- Institute of Physics
- Academia Sinica
- Taipei 11529
- Taiwan
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Lin WS, Jian ZJ, Lin HM, Lai LC, Chiou WA, Hwu YK, Wu SH, Chen WC, Yao YD. Synthesis and Characterization of Iron Nanowires. J CHIN CHEM SOC-TAIP 2012. [DOI: 10.1002/jccs.201200263] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Chen SY, Chiang DP, Yao YD, Yu CC, Chen YY, Wu JM, Lin HM. Effects of Os inserted layers on the microstructures and magnetic properties of the FePt films. J Nanosci Nanotechnol 2011; 11:11133-11137. [PMID: 22409071 DOI: 10.1166/jnn.2011.3997] [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: 05/31/2023]
Abstract
The microstructure and magnetic properties of multilayer [Os(t)/FePt(x)]n films on a glass substrate with a 10 nm Os buffer layer by ion beam sputtering have been studied as a function of the annealing temperatures between 300 and 800 degrees C. Here, t = 0.2, 1 or 5 nm and x varied from 10, 20, 25, 50, to 100 nm with its associated n value of 10, 5, 4, 2, and 1, respectively. No diffusion evidence was found in samples with a thin Os layer and t > or = 1 nm. The average grain size of the multilayer films can be well controlled by both annealing temperature and thickness of the FePt layer by a very thin Os space layer with t > or = 1 nm. The enhancement of H(c) can be understood from the fact that for a FePt film with an Os spacer layers, the increasing number of Os layer will inhibit the grain growth of FePt grains and enriches the grain boundary. We have experimentally demonstrated that even with a very thin 1 nm Os spacer layers, the [Os(t)/FePt(x)]n multilayer films can exhibit good hard magnetic properties and are attractive candidates for ultrahigh density magnetic recording media.
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Affiliation(s)
- S Y Chen
- Institute of Applied Science and Engineering, Fu Jen University, Taipei 242, Taiwan
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Chang HW, Tsay JS, Hung YC, Chan WY, Su WB, Chang CS, Yao YD. Investigation of magnetic properties and microstructure of ultrathin Co films grown on Si(111)- 7 x 7 surface. J Nanosci Nanotechnol 2011; 11:2696-2699. [PMID: 21449457 DOI: 10.1166/jnn.2011.2728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Magnetic properties and growth mechanism of ultrathin Co films on Si(111)-7 x 7 surface have been studied by using both surface magneto-optic Kerr effect (SMOKE) and scanning tunneling microscopy (STM), respectively. STM results show that the growth mechanism of ultrathin Co films on Si(111)-7 x 7 surface at room temperature belongs to Stranski-Krastanov (SK) growth mode. Due to formation of CoSi2 layer, no magnetic signal could be detected by SMOKE for 1-4 ML Co deposited on Si(111) surface. Because of rougher surface, both longitudinal and perpendicular magnetic anisotropy configuration appear for 4.2-10 ML Co/Si(111) films. When the Co thickness is increased to 10 ML, only longitudinal anisotropy configuration is found, resulting from the contribution to the volume anisotropy. Furthermore, in-plane coercivity increases with Co coverage because of enhancement of ferromagnetic coupling with Co thickness, out-of-plane coercivity increases with Co coverage due to the increment of demagnetized field, induced by the rougher Co surface and pinhole structures.
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Affiliation(s)
- H W Chang
- Department of Physics, Tunghai University, Taichung, 407 Taiwan, ROC
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Wei DH, Cheng KW, Yao YD, Hsu SY, Wei PK, Huang JH. Color variation in periodic Ag line arrays patterned by using electron-beam lithography. J Nanosci Nanotechnol 2010; 10:4581-4585. [PMID: 21128460 DOI: 10.1166/jnn.2010.1690] [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
Periodic Ag line arrays with different line pitches from 500 nm to 950 nm on ITO coated glass substrates have been fabricated by using electron-beam lithography (EBL) technique for studying the color light guide in a display system. The patterned Ag line array is used as a light outcoupling and color-selection component due to the emission wavelength changed by the Ag line arrays with different periodic distances that could achieve color variation. We have demonstrated that the ITO coated glass substrates containing periodic Ag line arrays with varied line pitches can be used as a color filter in a display device. This means that with a proper metallic nanostructure layer, the red, green, and blue colors in a display system can be obtained without a traditional color filter for modern multi-applications of optoelectronic display devices.
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Affiliation(s)
- D H Wei
- Department of Mechanical Engineering, National Taipei University of Technology, Taipei 106, Taiwan
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Chang HW, Wu BF, Yao YD, Su WB, Chang CS. Co nanoislands on Au(111) and Cu(111) surfaces studied by scanning tunneling microscopy and spectroscopy. J Nanosci Nanotechnol 2010; 10:4663-4666. [PMID: 21128475 DOI: 10.1166/jnn.2010.1686] [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] [Indexed: 05/30/2023]
Abstract
Co nanoislands on the Au(111) and Cu(111) surfaces have been studied by scanning tunneling microscopy and spectroscopy. The experimental results showed that Co nanoislands prefer to aggregate at the step edge and dislocation sites on the reconstructed Au(111) surface and at the step edge on the Cu(111) surface, respectively. In addition, based on dZ/dV-V spectra, in both the Co/Au(111) and the Co/Cu(111) systems, Gundlach oscillation was observed. From the peak shift of dZ/dV-V spectra between Co nanoisland and substrate surface, we can quantitatively obtain that the constant energy separation is -0.13 +/- 0.01 eV for the Co/Au(111) system, and 0.41 +/- 0.02 eV for the Co/Cu(111) system, respectively. These values indicate the work function difference between Co nanoisland and these surfaces.
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Affiliation(s)
- H W Chang
- Department of Physics, Tunghai University, Taichung, 407 Taiwan
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Lin CL, Lu SM, Su WB, Shih HT, Wu BF, Yao YD, Chang CS, Tsong TT. Manifestation of work function difference in high order Gundlach oscillation. Phys Rev Lett 2007; 99:216103. [PMID: 18233232 DOI: 10.1103/physrevlett.99.216103] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2007] [Indexed: 05/25/2023]
Abstract
Gundlach oscillation (or the standing-wave state) is a general phenomenon manifesting in the tunneling spectrum acquired from a metal surface using scanning tunneling spectroscopy. Previous studies relate the energy shift between peaks of the lowest-order Gundlach oscillation observed on the thin film and the metal substrate to the difference in their work functions. By observing Gundlach oscillations on Ag/Au(111), Ag/Cu(111), and Co/Cu(111) systems, we demonstrate that the work function difference is not the energy shift of the lowest order but the ones of higher order where a constant energy shift exhibits. Higher order Gundlach oscillations can thus be applied to determine the work function of thin metal films precisely.
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Affiliation(s)
- C L Lin
- Institute of Physics, Academia Sinica, Nankang, Taipei, Taiwan, Republic of China
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Chen YY, Huang PH, Ou MN, Wang CR, Yao YD, Lee TK, Ho MY, Lawrence JM, Booth CH. Kondo interactions and magnetic correlations in CePt2 nanocrystals. Phys Rev Lett 2007; 98:157206. [PMID: 17501380 DOI: 10.1103/physrevlett.98.157206] [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: 12/07/2006] [Indexed: 05/15/2023]
Abstract
The evolution of the Kondo effect and antiferromagnetic (AF) correlations with size reduction in CePt2 nanoparticles (3.1-26 nm) is studied by analysis of the temperature-dependent specific heat and magnetic susceptibility. The AF correlations diminish with size reduction. The Kondo effect predominates at small particle size with trivalent, small Kondo temperature (TK) magnetic regions coexisting with strongly mixed-valent, large TK nonmagnetic regions. We discuss the role of structural disorder, background density of states and the electronic quantum size effect on the results.
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Affiliation(s)
- Y Y Chen
- Institute of Physics, Academia Sinica, Taipei, Taiwan, Republic of China.
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Rao GN, Yao YD, Chen YL, Wu KT, Chen JW. Particle size and magnetic field-induced optical properties of magnetic fluid nanoparticles. Phys Rev E Stat Nonlin Soft Matter Phys 2005; 72:031408. [PMID: 16241436 DOI: 10.1103/physreve.72.031408] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2005] [Revised: 06/15/2005] [Indexed: 05/05/2023]
Abstract
Magnetite nanoparticles with diameters of 7, 9, and 12 nm have been prepared by a chemical coprecipitation method. The transmission of light through magnetic fluid containing these nanoparticles has been investigated as a function of film thickness with wavelength between 400 and 750 nm, and applied magnetic fields up to 275 Oe. The transmission threshold shifts to the lower wavelength side with decreasing magnetic fluid film thickness as well as the particle size. For a given film thickness, the transmittance increases with increasing magnetic field for films with a particle size of 7 and 9 nm, but decreases in the 12-nm film. This is attributed to the competition between the van der Waals and dipole-dipole interaction.
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Affiliation(s)
- G Narsinga Rao
- Institute of Physics, Academia Sinica, Taipei, Taiwan, Republic of China
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12
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Klik I, Yao YD. Resonant exit time in stochastic and deterministic systems. Phys Rev E Stat Nonlin Soft Matter Phys 2005; 71:067102. [PMID: 16089915 DOI: 10.1103/physreve.71.067102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2004] [Revised: 11/16/2004] [Indexed: 05/03/2023]
Abstract
The motion of a particle in the field of a time-dependent potential is studied here both at absolute zero and in the presence of thermal agitation. The potential executes either random fluctuations or deterministic harmonic oscillations. Assuming absorbing boundaries it is always possible to find an exit time tau(ex)(kappa) which has a local minimum as a function of the potential flip rate kappa. Thus resonant activation, usually associated with diffussive systems, exists in purely deterministic systems as well. Thermal agitation merely extends the range of admissible initial conditions and renders all exit times finite.
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Affiliation(s)
- I Klik
- Institute of Physics, Academia Sinica, Taipei 115, Taiwan, Republic of China
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Klik I, Yao YD. Resonant activation in a system with deterministic oscillations of barrier height. Phys Rev E Stat Nonlin Soft Matter Phys 2001; 64:012101. [PMID: 11461302 DOI: 10.1103/physreve.64.012101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2000] [Indexed: 05/23/2023]
Abstract
A thermally relaxing system with a harmonically oscillating barrier height is considered. The dynamics of the system are described by a Smoluchowski equation with a time dependent right hand side. For both absorbing and reflecting boundary conditions, the solutions of this equation show that the oscillating system has the same resonant properties, and the same dependence on initial conditions, respectively, on the phase of the harmonic oscillations, as a conventional resonant system in which the barrier executes dichotomic Markovian fluctuations.
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Affiliation(s)
- I Klik
- Institute of Physics, Academia Sinica, Nankang, Taiwan 115, Taiwan
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Klik I, Yao YD. Solution of a separable smoluchowski equation in one spatial dimension. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 2000; 62:4469-4472. [PMID: 11088991 DOI: 10.1103/physreve.62.4469] [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: 08/02/1999] [Revised: 04/20/2000] [Indexed: 05/23/2023]
Abstract
An approximate solution of a separable Smoluchowski equation in one spatial dimension is constructed here in the form of a finite eigenfunction expansion. The spectrum of the Smoluchowski operator, and the corresponding eigenfunctions, are computed using the so called shooting method of adjoints. Explicit numerical solutions are presented for static and fluctuating potentials, and it is shown that for any smooth initial probablity distribution the finite expansion holds on all time scales. The method is applicable to any linear eigenproblem on a finite one-dimensional interval; the solution of the Sturm-Liouville problem has a particularly convenient form.
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Affiliation(s)
- I Klik
- Institute of Physics, Academia Sinica, Taipei 115, Taiwan
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Chen YY, Yao YD, Wang CR, Li WH, Chang CL, Lee TK, Hong TM, Ho JC, Pan SF. Size-induced transition from magnetic ordering to kondo behavior in (Ce,Al) compounds. Phys Rev Lett 2000; 84:4990-4993. [PMID: 10990849 DOI: 10.1103/physrevlett.84.4990] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/1999] [Indexed: 05/23/2023]
Abstract
Magnetic ordering and Kondo behavior coexist in three (Ce,Al)-based compounds: CeAl2, Ce3Al, and Ce3Al11. A common feature apparently independent of crystal structures also prevails in terms of the size-induced transition between these two magnetic phenomena. As the particle size is reduced to nanoscale, the specific heat anomaly associated with the magnetic ordering diminishes. Although the Kondo temperature also decreases, the entropy associated with Kondo anomaly exhibits a large increase. This results in an enhancement of the Kondo behavior and an increased coefficient gamma of the linear term in specific heat. For example, in 80 A CeAl2 the extrapolated r(0) reaches 9000 mJ mol Ce-1 K-2.
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Affiliation(s)
- YY Chen
- Institute of Physics, Academia Sinica, Taipei, Taiwan, Republic of China
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Abstract
Single cortical auditory neurons sequentially isolated within orthogonal electrode penetrations in the mouse were studied using tonal stimulation. They had common functional properties, such as firing pattern, best frequency, minimum threshold, sharpness of frequency tuning and onset latency. The finding suggests that there is columnar organization in the cortex.
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Affiliation(s)
- J X Shen
- Laboratory of Visual Information Processing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing, China.
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Qian ZM, Pu YM, Wang Q, Ke Y, Yao YD, Chen WF, Shen X, Feng YM, Tang PL. Cerebellar granule cells acquire transferrin-free iron by a carrier-mediated process. Neuroscience 1999; 92:577-82. [PMID: 10408606 DOI: 10.1016/s0306-4522(99)00008-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [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: 11/19/2022]
Abstract
In this study, the mechanism of transferrin-free iron uptake by brain neuronal cells was investigated using the cultured cerebellar granule cells. Effects of incubation time, iron concentration, temperature and other divalent metals on the cellular uptake were determined. After five days of plating, the cells were incubated with different concentrations of transferrin-free iron in isotonic sucrose solution at different temperatures for a certain time. The cellular transferrin-free iron uptake was analysed by measuring the cellular radioactivity with a gamma-counter. The result showed that the cultured cerebellar granule cells had the capacity to acquire transferrin-free iron at pH 6.5, at which it was demonstrated that transferrin binds iron very poorly and only very little transferrin can be internalized by reticulocytes and HeLa cells. The iron uptake by cells increased with incubation time in a linear manner at a rate of 0.1076 pmol/microg protein/min within the first 10 min. The uptake was time- and temperature-dependent, iron concentration saturable, and inhibited by several divalent metal ions, such as Co2+, Zn2+, Mn2+ and Ni2+. These characteristics of transferrin-free iron uptake by the cultured cerebellar granule cells observed in this study, similar to those obtained from cells outside of the brain, implied that a carrier-mediated iron transport system might be present on the membrane of this type of brain neuronal cells. In addition, no significant difference in malondialdehyde measurement was found when the cells were incubated without or with the lower concentrations of iron (< 4 microM) for 20 min at 37 degrees C, demonstrating that this system was valid for studying membrane iron transport in this type of brain neuronal cell.
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Affiliation(s)
- Z M Qian
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon
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Klik I, Yao YD. Semianalytic solution of the Kramers exit problem for a small ferromagnetic particle. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 1999; 59:6444-7. [PMID: 11969629 DOI: 10.1103/physreve.59.6444] [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: 01/12/1999] [Indexed: 04/18/2023]
Abstract
The distribution Q(t) of magnetization reversal times in a small uniaxial particle is computed here directly from Brown's Fokker-Planck equation. Constant applied field and axial symmetry are assumed. The Laplace transform of Q(t) has the form Q(z)=F(1)(z)/F(2)(z) where the regular functions F(i)(z) are defined by a solution of a Volterra integral equation. A separate integral equation is derived for the function dF(2)(z)/dz, and the poles and residues of Q(z) may then be found numerically with arbitary precision.
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Affiliation(s)
- I Klik
- Institute of Physics, Academia Sinica, Taipei 115, Taiwan
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Klik I, Yao YD, Chang CR. Non-Markovian thermal relaxation at elevated temperatures. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 1995; 52:6892-6895. [PMID: 9964208 DOI: 10.1103/physreve.52.6892] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [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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Huang JC, Liou Y, Yao YD, Yang WT, Chang CP, Liao SY, Hu YM. Large crystalline-induced magnetic anisotropy and field-direction-dependent magnetoresistance in Co(11-bar00)/Cr(211) superlattices. Phys Rev B Condens Matter 1995; 52:13110-13113. [PMID: 9980491 DOI: 10.1103/physrevb.52.r13110] [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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Chen YY, Yao YD, Hsiao SS, Jen SU, Lin BT, Lin HM, Tung CY. Specific-heat study of nanocrystalline palladium. Phys Rev B Condens Matter 1995; 52:9364-9369. [PMID: 9979981 DOI: 10.1103/physrevb.52.9364] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [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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Ho JC, Hamdeh HH, Chen YY, Lin SH, Yao YD, Willey RJ, Oliver SA. Low-temperature calorimetric properties of zinc ferrite nanoparticles. Phys Rev B Condens Matter 1995; 52:10122-10126. [PMID: 9980060 DOI: 10.1103/physrevb.52.10122] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [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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