426
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Qiu Y, Bao W, Huang Q, Yildirim T, Simmons JM, Green MA, Lynn JW, Gasparovic YC, Li J, Wu T, Wu G, Chen XH. Crystal structure and antiferromagnetic order in NdFeAsO1-xFx (x=0.0 and 0.2) superconducting compounds from neutron diffraction measurements. PHYSICAL REVIEW LETTERS 2008; 101:257002. [PMID: 19113743 DOI: 10.1103/physrevlett.101.257002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2008] [Indexed: 05/27/2023]
Abstract
The transition temperature T{C} approximately 26 K of the recently discovered superconductor LaFeAsO1-xFx is extremely sensitive to the lanthanide ion, reaching 55 K for the Sm containing oxypnictides. Therefore, it is important to determine how the moment on the lanthanide affects the overall magnetism in these systems. Here we report a neutron diffraction study of the Nd oxypnictides. Long-ranged antiferromagnetic order is apparent in NdFeAsO below 1.96 K. Rietveld refinement shows that both Fe and Nd magnetic ordering are required to describe the observed data with the staggered moment 1.55(4)micro{B}/Nd and 0.9(1)micro{B}/Fe at 0.3 K. The other structural properties such as the tetragonal-orthorhombic distortion are found to be very similar to those in LaFeAsO. Neither the magnetic ordering nor the structural distortion occur in the superconducting sample NdFeAsO0.80F0.20 at any temperatures down to 1.5 K.
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427
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Liu G, Huang Q, Kaduk J, Yang Z, Lucas C, Wong-Ng W. X-ray and neutron powder diffraction studies of Ba(NdxY2−x)CuO5. J SOLID STATE CHEM 2008. [DOI: 10.1016/j.jssc.2008.08.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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428
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Huang Q, Yang C, Yu G, Mao ZS. Sensitivity Study on Modeling an Internal Airlift Loop Reactor Using a Steady 2D Two-Fluid Model. Chem Eng Technol 2008. [DOI: 10.1002/ceat.200700278] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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429
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Li R, Mock R, Huang Q, Abad J, Hartung J, Kinard G. A reliable and inexpensive method of nucleic acid extraction for the PCR-based detection of diverse plant pathogens. J Virol Methods 2008; 154:48-55. [DOI: 10.1016/j.jviromet.2008.09.008] [Citation(s) in RCA: 170] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Revised: 09/09/2008] [Accepted: 09/11/2008] [Indexed: 11/25/2022]
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430
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Zhao J, Huang Q, de la Cruz C, Li S, Lynn JW, Chen Y, Green MA, Chen GF, Li G, Li Z, Luo JL, Wang NL, Dai P. Structural and magnetic phase diagram of CeFeAsO(1- x)F(x) and its relation to high-temperature superconductivity. NATURE MATERIALS 2008; 7:953-959. [PMID: 18953342 DOI: 10.1038/nmat2315] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Accepted: 09/26/2008] [Indexed: 05/27/2023]
Abstract
Recently, high-transition-temperature (high-Tc) superconductivity was discovered in the iron pnictide RFeAsO(1-x)F(x) (R, rare-earth metal) family of materials. We use neutron scattering to study the structural and magnetic phase transitions in CeFeAsO(1-x)F(x) as the system is tuned from a semimetal to a high-Tc superconductor through fluorine (F) doping, x. In the undoped state, CeFeAsO develops a structural lattice distortion followed by a collinear antiferromagnetic order with decreasing temperature. With increasing fluorine doping, the structural phase transition decreases gradually and vanishes within the superconductivity dome near x=0.10, whereas the antiferromagnetic order is suppressed before the appearance of superconductivity for x>0.06, resulting in an electronic phase diagram remarkably similar to that of the high-Tc copper oxides. Comparison of the structural evolution of CeFeAsO(1-x)F(x) with other Fe-based superconductors suggests that the structural perfection of the Fe-As tetrahedron is important for the high-Tc superconductivity in these Fe pnictides.
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431
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McQueen TM, Stephens PW, Huang Q, Klimczuk T, Ronning F, Cava RJ. Successive orbital ordering transitions in NaVO2. PHYSICAL REVIEW LETTERS 2008; 101:166402. [PMID: 18999690 DOI: 10.1103/physrevlett.101.166402] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2008] [Indexed: 05/27/2023]
Abstract
Physical property measurements on samples of triangular-lattice NaVO2 reveal two successive orbital ordering transitions. At 300 K, the structure is rhombohedral. At 98 K, the system undergoes a second-order transition to a monoclinic phase in which the in-plane V-V distances separate into four short and two long bonds, corresponding to orbital ordering of one electron per V3+. Below 93 K, there is a first-order transition to a second monoclinic phase with four long and two short V-V bonds, consistent with orbital ordering of two electrons per V3+. Long range magnetic ordering of 0.98(2)mu_(B) per V3+ (3d(2)) sets in at the 93 K structural transition. The orbital ordering relieves the geometric frustration and leads to a magnetically ordered ground state.
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432
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West D, Huang Q, Zandbergen H, McQueen T, Cava R. Structural disorder, octahedral coordination and two-dimensional ferromagnetism in anhydrous alums. J SOLID STATE CHEM 2008. [DOI: 10.1016/j.jssc.2008.07.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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433
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Lao T, Gu W, Huang Q. A meta-analysis on XRCC1 R399Q and R194W polymorphisms, smoking and bladder cancer risk. Mutagenesis 2008; 23:523-32. [DOI: 10.1093/mutage/gen046] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
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434
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West D, McQueen T, Huang Q, Cava R. Structural and magnetic properties of pyrochlore solid solutions (Y,Lu)2Ti2−x(Nb,Ta)xO7±y. J SOLID STATE CHEM 2008. [DOI: 10.1016/j.jssc.2008.03.030] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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435
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Wei MK, Wu QP, Huang Q, Wu JL, Zhang JM. Plasma membrane damage to Candida albicans caused by chlorine dioxide (ClO2). Lett Appl Microbiol 2008; 47:67-73. [PMID: 18624985 DOI: 10.1111/j.1472-765x.2008.02387.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIM To investigate the plasma membrane damage of chlorine dioxide (ClO(2)) to Candida albicans ATCC10231 at or below the minimal fungicidal concentration (MFC). METHODS AND RESULTS ClO(2) at MFC or below was adopted to treat the cell suspensions of C. albicans ATCC10231. Using transmission electron microscopy, no visible physiological alteration of cell shape and plasma membrane occurred. Potassium (K(+)) leakages were significant; likewise, it showed time- and dose-dependent increases. However, adenosine triphosphate (ATP) leakages were very slight. Research shows that when 99% of the cells were inactivated, the leakage was measured at 0.04% of total ATP. Compared with the mortality-specific fluorescent dye of DiBAC(4)(3), majority of the inactivated cells were poorly stained by propidium iodide, another mortality-specific fluorescent dye which can be traced by flow cytometry. CONCLUSION At or below MFC, ClO(2) damages the plasma membranes of C. albicans mainly by permeabilization, rather than by the disruption of their integrity. K(+) leakage and the concomitant depolarization of the cell membrane are some of the critical events. SIGNIFICANCE AND IMPACT OF THE STUDY These insights into membrane damages are helpful in understanding the action mode of ClO(2).
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436
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McQueen TM, West DV, Muegge B, Huang Q, Noble K, Zandbergen HW, Cava RJ. Frustrated ferroelectricity in niobate pyrochlores. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2008; 20:235210. [PMID: 21694301 DOI: 10.1088/0953-8984/20/23/235210] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The crystal structures of the A(2)B(2)O(7-x) niobium based pyrochlores Y(2)(Nb(0.86)Y(0.14))(2)O(6.91), CaYNb(2)O(7), and Y(2)NbTiO(7) are reported, determined by means of powder neutron diffraction. These compounds represent the first observation of B-site displacements in the pyrochlore structure: the B-site ions are found to be displaced from the ideal pyrochlore positions, creating electric dipoles. The orientations of these dipoles are fully analogous to orientations of the magnetic moments in Ising spin based magnetically frustrated pyrochlores. Diffuse scattering in electron diffraction patterns shows that the displacements are only short range ordered, indicative of geometric frustration of the collective dielectric state of the materials. Comparison to the crystal structure of the Nb(5+) (d(0)) pyrochlore La(2)ScNbO(7) supports the prediction that charge singlets, driven by the tendency of Nb to form metal-metal bonds, are present in these pyrochlores. The observed lack of long range order to these singlets suggests that Nb(4+) based pyrochlores represent the dielectric analogy to the geometric frustration of magnetic moments observed in rare earth pyrochlores.
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437
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Dorfman R, Nalpathamkalam T, Taylor C, Gonska T, Yuan X, Huang Q, Lin F, Jiang B, Corey M, Tsui L, Durie P, Zielenski J. Do in silico tools predict the clinical consequences of CFTR missense mutations? J Cyst Fibros 2008. [DOI: 10.1016/s1569-1993(08)60014-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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438
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Zhang Y, Wang Z, Huang Q, Shu W. Phosphoenolpyruvate carboxylase activity in ear organs is related to protein concentration in grains of winter wheat. J Cereal Sci 2008. [DOI: 10.1016/j.jcs.2007.04.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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439
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Lei Z, Liu G, Huang Q, Lv M, Zu R, Zhang GM, Feng ZH, Huang B. SCF and IL-31 rather than IL-17 and BAFF are potential indicators in patients with allergic asthma. Allergy 2008; 63:327-32. [PMID: 18053009 DOI: 10.1111/j.1398-9995.2007.01566.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Although the prevalence of allergic asthma increased quickly in the past decade, the diagnostic criteria have not been well established. The aim of the present study was to explore whether stem cell factor (SCF), B cell-activating factor (BAFF), and cytokines interleukin (IL)-17 and IL-31 are usable parameters for the diagnosis of allergic asthmatics. METHODS Blood samples were collected from patients with allergic asthma, control patients, and healthy control subjects. The serum concentrations of SCF, BAFF, IL-17, and IL-31 were measured by enzyme-linked immunosorbent assay. The corresponding mRNA levels in peripheral blood mononuclear cells (PBMCs) were determined by real-time reverse-transcription polymerase chain reaction. RESULTS A good correlation existed between protein levels of SCF and IL-31 and their mRNA levels (SCF: r = 0.6162; IL-31: r = 0.5463). The serum concentrations of SCF and IL-31 in allergic asthmatic patients, but not control patients, were significantly higher than those in normal control subjects (SCF: median 1.83 vs 0.85 ng/ml, P < 0.01; IL-31: 50.15 vs 10.01 pg/ml, P < 0.001). Consistently, the levels of SCF and IL-31 mRNAs in allergic asthmatic patients' PBMCs were also significantly higher than those in normal control subjects (P = 0.002 and P < 0.001, respectively). CONCLUSIONS These findings suggest that allergic asthma is characterized by an elevation of cytokines SCF and IL-31 and the measurement of their expression at either protein level in serum or mRNA level in PBMCs will be a valuable parameter for the diagnosis of allergic asthma.
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440
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Huang Q, Zhai RY, Dai DK. Interventional treatment of hepatic artery stenosis after orthotopic liver transplantation with balloon-expandable coronary stent. Transplant Proc 2008; 39:3245-50. [PMID: 18089364 DOI: 10.1016/j.transproceed.2007.03.109] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2006] [Accepted: 03/26/2007] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The aim of this study was to evaluate the efficacy of hepatic artery stenting with a balloon-expandable coronary stent for the treatment of hepatic artery stenosis (HAS) after orthotopic liver transplantation (OLT). PATIENTS AND METHODS We performed retrospective review of all 11 patients who underwent hepatic artery stenting after a diagnosis of HAS. RESULTS A total of 13 balloon-expandable coronary stents were placed into 11 patients. The technical and immediate success rate was 100%; all stents remained patent during follow-up. One patient required 2 stents due to the length of the stenotic artery. Another underwent a second stenting after developing restenosis proximal to the original stenotic site. No procedure-related complications occurred, and no surgical revascularization or retransplantation was required during follow-up. CONCLUSIONS A balloon-expandable coronary stent can play a role in the management of HAS. It can be used with great safety, with immediate as well as longer-term success.
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441
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Garlea VO, Jin R, Mandrus D, Roessli B, Huang Q, Miller M, Schultz AJ, Nagler SE. Magnetic and orbital ordering in the spinel MnV2O4. PHYSICAL REVIEW LETTERS 2008; 100:066404. [PMID: 18352495 DOI: 10.1103/physrevlett.100.066404] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2007] [Indexed: 05/26/2023]
Abstract
Neutron inelastic scattering and diffraction techniques have been used to study the MnV2O4 spinel system. Our measurements show the existence of two transitions to long-range ordered ferrimagnetic states, the first collinear and the second noncollinear. The lower temperature transition, characterized by development of antiferromagnetic components in the basal plane, is accompanied by a tetragonal distortion and the appearance of a gap in the magnetic excitation spectrum. The low-temperature noncollinear magnetic structure has been definitively resolved. Taken together, the crystal and magnetic structures indicate a staggered ordering of the V d orbitals. The anisotropy gap is a consequence of unquenched V orbital angular momentum.
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442
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Choi YJ, Yi HT, Lee S, Huang Q, Kiryukhin V, Cheong SW. Ferroelectricity in an ising chain magnet. PHYSICAL REVIEW LETTERS 2008; 100:047601. [PMID: 18352334 DOI: 10.1103/physrevlett.100.047601] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2007] [Indexed: 05/26/2023]
Abstract
We report discovery of collinear-magnetism-driven ferroelectricity in the Ising chain magnet Ca3Co2-xMn(x)O6 (x approximately 0.96). Neutron diffraction shows that Co2+ and Mn4+ ions alternating along the chains exhibit an up-up-down-down ( upward arrow upward arrow downward arrow downward arrow) magnetic order. The ferroelectricity results from the inversion symmetry breaking in the upward arrow upward arrow downward arrow downward arrow spin chain with an alternating charge order. Unlike in spiral magnetoelectrics where antisymmetric exchange coupling is active, the symmetry breaking in Ca3(Co,Mn)2O6 occurs through exchange striction associated with symmetric superexchange.
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443
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Kim JT, Weber N, Shin GH, Huang Q, Liu SX. The study of beta-lactoglobulin adsorption on polyethersulfone thin film surface using QCM-D and AFM. J Food Sci 2008; 72:E214-21. [PMID: 17995774 DOI: 10.1111/j.1750-3841.2007.00344.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The adsorption process of beta-lactoglobulin on the polyethersulfone-coated surface has been investigated using a quartz crystal microbalance with dissipation monitoring (QCM-D), which allowed simultaneous measurements of frequency and energy dissipation changes caused by the formation of a beta-lactoglobulin layer during the protein adsorption process. The results showed that the protein adsorption on the spin-coated polyethersulfone surface consisted of reversible and irreversible adsorption processes, and the irreversible adsorption was the principal factor to cause the permanent protein adsorption onto the polymer surface. The amount of irreversible adsorption of beta-lactoglobulin increased significantly, from 380.5 +/- 23.2 to 745.5 +/- 29.7 ng/cm2, when the concentration of beta-lactoglobulin solution varied from 0.1% to 2.0% (w/v). The pH also played an important role in the protein adsorption. When the pH of the solution varied from 7.0 to 3.0, the amount of irreversible adsorption of beta-lactoglobulin increased from 427.1 +/- 80.7 to 741.2 +/- 135.1 ng/cm2.
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444
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Zhi CY, Bando Y, Tang CC, Huang Q, Golberg D. Boron nitride nanotubes: functionalization and composites. ACTA ACUST UNITED AC 2008. [DOI: 10.1039/b804575e] [Citation(s) in RCA: 203] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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445
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Lau G, McQueen T, Huang Q, Zandbergen H, Cava R. Long- and short-range order in stuffed titanate pyrochlores. J SOLID STATE CHEM 2008. [DOI: 10.1016/j.jssc.2007.10.025] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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446
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Lee SH, Kikuchi H, Qiu Y, Lake B, Huang Q, Habicht K, Kiefer K. Quantum-spin-liquid states in the two-dimensional kagome antiferromagnets ZnxCu4-x(OD)6Cl2. NATURE MATERIALS 2007; 6:853-7. [PMID: 17721540 DOI: 10.1038/nmat1986] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2007] [Accepted: 07/18/2007] [Indexed: 05/16/2023]
Abstract
A three-dimensional system of interacting spins typically develops static long-range order when it is cooled. If the spins are quantum (S=1/2), however, novel quantum paramagnetic states may appear. The most highly sought state among them is the resonating-valence-bond state, in which every pair of neighbouring quantum spins forms an entangled spin singlet (valence bonds) and these singlets are quantum mechanically resonating among themselves. Here we provide an experimental indication for such quantum paramagnetic states existing in frustrated antiferromagnets, Zn(x)Cu(4-x)(OD)(6)Cl(2), where the S=1/2 magnetic Cu2+ moments form layers of a two-dimensional kagome lattice. We find that in Cu(4)(OD)(6)Cl(2), where distorted kagome planes are weakly coupled, a dispersionless excitation mode appears in the magnetic excitation spectrum below approximately 20 K, whose characteristics resemble those of quantum spin singlets in a solid state, known as a valence-bond solid, that breaks translational symmetry. Doping with non-magnetic Zn2+ ions reduces the distortion of the kagome lattice, and weakens the interplane coupling but also dilutes the magnetic occupancy of the kagome lattice. The valence-bond-solid state is suppressed, and for ZnCu(3)(OD)(6)Cl(2), where the kagome planes are undistorted and 90% occupied by the Cu2+ ions, the low-energy spin fluctuations become featureless.
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447
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Chen M, Huang Q, Zheng S. Activation analysis of tritium breeder materials in the FDS-II fusion power reactor. FUSION ENGINEERING AND DESIGN 2007. [DOI: 10.1016/j.fusengdes.2007.05.033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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448
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Ge C, Jia J, Gao S, Huang Q, Li F, Jois M. Feeding a natural plant extract affects growth
performance in beef cattle. JOURNAL OF ANIMAL AND FEED SCIENCES 2007. [DOI: 10.22358/jafs/74612/2007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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449
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Chen Y, Aguirre AD, Hsiung PL, Desai S, Herz PR, Pedrosa M, Huang Q, Figueiredo M, Huang SW, Koski A, Schmitt JM, Fujimoto JG, Mashimo H. Ultrahigh resolution optical coherence tomography of Barrett's esophagus: preliminary descriptive clinical study correlating images with histology. Endoscopy 2007; 39:599-605. [PMID: 17611914 DOI: 10.1055/s-2007-966648] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND STUDY AIMS Endoscopic ultrahigh resolution optical coherence tomography (UHR OCT) achieves an axial image resolution of approximately 5 microm, which is 2 - 3 times finer than standard endoscopic OCT imaging. This study investigated the capability of endoscopic UHR OCT for imaging patients with Barrett's esophagus. PATIENTS AND METHODS Fivty volunteers previously diagnosed with Barrett's esophagus underwent UHR OCT. Imaging was performed at 1.3 microm wavelengths with approximately 5 microm axial and approximately 15 microm transverse resolutions using a 1.8 mm/diameter linear-scanning catheter introduced through the accessory channel of a standard endoscope. OCT images were compared with endoscopic diagnosis and pinch biopsy histological appearances. RESULTS UHR OCT images of normal esophagus, Barrett's esophagus, high grade dysplasia and esophageal adenocarcinoma were evaluated. UHR OCT images of the normal esophagus exhibited characteristic layered architecture with uniform epithelium, while images of Barrett's esophagus corresponded to crypt-like glandular structures. High grade dysplasia and esophageal adenocarcinoma images exhibited more heterogeneous structures corresponding to irregular, heterogeneous tissue morphology from distorted and cribriform or villiform glandular architecture. Fine features can be discerned more clearly with endoscopic UHR OCT. CONCLUSIONS This study evaluated new endoscopic OCT technology and demonstrated the feasibility of carrying out UHR OCT imaging in conjunction with standard endoscopy for in vivo real-time imaging of Barrett's esophagus, dysplasia, and esophageal adenocarcinoma. A survey of normal and abnormal upper gastrointestinal tissues was performed using a research prototype OCT system with the highest axial resolution to date, and can serve as a baseline for future investigation.
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450
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Kenzelmann M, Lawes G, Harris AB, Gasparovic G, Broholm C, Ramirez AP, Jorge GA, Jaime M, Park S, Huang Q, Shapiro AY, Demianets LA. Direct transition from a disordered to a multiferroic phase on a triangular lattice. PHYSICAL REVIEW LETTERS 2007; 98:267205. [PMID: 17678126 DOI: 10.1103/physrevlett.98.267205] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2007] [Indexed: 05/16/2023]
Abstract
We report the first direct transition from a paramagnetic and paraelectric phase to an incommensurate multiferroic in the triangular lattice antiferromagnet RbFe(MoO4)(2). Ferroelectricity is observed only when the magnetic structure has chirality and breaks inversion symmetry. A Landau expansion of symmetry-allowed terms in the free energy demonstrates that chiral magnetic order can give rise to a pseudoelectric field, whose temperature dependence agrees with experiment.
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