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1.
Zhonghua Gan Zang Bing Za Zhi ; 31(9): 961-968, 2023 Sep 20.
Artículo en Chino | MEDLINE | ID: mdl-37872092

RESUMEN

Objective: To compare the differences in the prevalence of mild micro-hepatic encephalopathy (MHE) among patients with cirrhosis by using the psychometric hepatic encephalopathy score (PHES) and the Stroop smartphone application (Encephal App) test. Methods: This prospective, multi-center, real-world study was initiated by the National Clinical Medical Research Center for Infectious Diseases and the Portal Hypertension Alliance and registered with International ClinicalTrials.gov (NCT05140837). 354 cases of cirrhosis were enrolled in 19 hospitals across the country. PHES (including digital connection tests A and B, digital symbol tests, trajectory drawing tests, and serial management tests) and the Stroop test were conducted in all of them. PHES was differentiated using standard diagnostic criteria established by the two studies in China and South Korea. The Stroop test was evaluated based on the criteria of the research and development team. The impact of different diagnostic standards or methods on the incidence of MHE in patients with cirrhosis was analyzed. Data between groups were differentiated using the t-test, Mann-Whitney U test, and χ (2) test. A kappa test was used to compare the consistency between groups. Results: After PHES, the prevalence of MHE among 354 cases of cirrhosis was 78.53% and 15.25%, respectively, based on Chinese research standards and Korean research normal value standards. However, the prevalence of MHE was 56.78% based on the Stroop test, and the differences in pairwise comparisons among the three groups were statistically significant (kappa = -0.064, P < 0.001). Stratified analysis revealed that the MHE prevalence in three groups of patients with Child-Pugh classes A, B, and C was 74.14%, 83.33%, and 88.24%, respectively, according to the normal value standards of Chinese researchers, while the MHE prevalence rates in three groups of patients with Child-Pugh classes A, B, and C were 8.29%, 23.53%, and 38.24%, respectively, according to the normal value standards of Korean researchers. Furthermore, the prevalence rates of MHE in the three groups of patients with Child-Pugh grades A, B, and C were 52.68%, 58.82%, and 73.53%, respectively, according to the Stroop test standard. However, among the results of each diagnostic standard, the prevalence of MHE showed an increasing trend with an increasing Child-Pugh grade. Further comparison demonstrated that the scores obtained by the number connection test A and the number symbol test were consistent according to the normal value standards of the two studies in China and South Korea (Z = -0.982, -1.702; P = 0.326, 0.089), while the other three sub-tests had significant differences (P < 0.001). Conclusion: The prevalence rate of MHE in the cirrhotic population is high, but the prevalence of MHE obtained by using different diagnostic criteria or methods varies greatly. Therefore, in line with the current changes in demographics and disease spectrum, it is necessary to enroll a larger sample size of a healthy population as a control. Moreover, the establishment of more reliable diagnostic scoring criteria will serve as a basis for obtaining accurate MHE incidence and formulating diagnosis and treatment strategies in cirrhotic populations.


Asunto(s)
Encefalopatía Hepática , Humanos , Encefalopatía Hepática/diagnóstico , Encefalopatía Hepática/epidemiología , Encefalopatía Hepática/etiología , Estudios Prospectivos , Índice de Severidad de la Enfermedad , Cirrosis Hepática/complicaciones , Cirrosis Hepática/diagnóstico , Psicometría/métodos
4.
Nat Commun ; 12(1): 3513, 2021 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-34112804

RESUMEN

The Kitaev quantum spin liquid epitomizes an entangled topological state, for which two flavors of fractionalized low-energy excitations are predicted: the itinerant Majorana fermion and the Z2 gauge flux. It was proposed recently that fingerprints of fractional excitations are encoded in the phonon spectra of Kitaev quantum spin liquids through a novel fractional-excitation-phonon coupling. Here, we detect anomalous phonon effects in α-RuCl3 using inelastic X-ray scattering with meV resolution. At high temperature, we discover interlaced optical phonons intercepting a transverse acoustic phonon between 3 and 7 meV. Upon decreasing temperature, the optical phonons display a large intensity enhancement near the Kitaev energy, JK~8 meV, that coincides with a giant acoustic phonon softening near the Z2 gauge flux energy scale. These phonon anomalies signify the coupling of phonon and Kitaev magnetic excitations in α-RuCl3 and demonstrates a proof-of-principle method to detect anomalous excitations in topological quantum materials.

5.
Phys Rev B ; 103(17)2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-37588030

RESUMEN

We report the magnetic ordering and structural distortion in PrFeAsO crystals, the basis compound for one of the oxypnictide superconductors, using high-resolution x-ray diffraction, neutron diffraction, and x-ray resonant magnetic scattering (XRMS). We find the structural tetragonal-to-orthorhombic phase transition at TS=147K, the AFM phase transition of the Fe moments at TFe=72K, and the Pr AFM phase transition at TPr=21K. Combined high-resolution neutron diffraction and XRMS show unambiguously that the Pr moments point parallel to the longer orthorhombic a axis and order antiferromagnetically along the a axis but ferromagnetically along the b and c directions in the stripelike AFM order. The temperature-dependent magnetic order parameter of the Pr moments shows no evidence for a reorientation of moments.

6.
Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi ; 32(5): 531-533, 2020 Oct 26.
Artículo en Chino | MEDLINE | ID: mdl-33185069

RESUMEN

OBJECTIVE: To assess the schistosomiasis transmission risk in Nanjing County, so as to provide the scientific evidence for the development of the schistosomiasis control strategy and consolidation of the control achievements. METHODS: On May 2019, the Deqiu Village in Deqiu Town and Baiyun Village in Nanjing Town of Yunnan Province, where schistosomiasis were historically relatively highly endemic, were selected to assess the risk of transmission of schistosomiasis by means of a retrospective review of the data pertaining to the historical endemic situation and schistosomiasis control, combined with a cross-sectional survey of snail and wild feces distribution. RESULTS: During the period between 2017 and 2018, the mean sero-prevalence rates of Schistosoma japonicum infections were 6.76% (202/2 990) and 2.86% (142/4 971) in humans and 0 (0/1 160) and 10.65% (31/291) in bovines in Deqiu and Baiyun villages of Nanjian County, respectively; however, no egg-positives were identified; in addition, there were 21.06 hm2 snail habitats found, but no S. japonicum infections were detected in snails. In 2019, there was 6.17 hm2 snail habitats detected, with 2.17% (245/11 298) occurrence of frames with snails and a 0.06 snails/0.1 m2 density of living snails; however, no positives for nucleic acid detection were seen in snails; among the 136 wild fecal samples captures from 23 settings, no S. japonicum infections were identified. CONCLUSIONS: The risk of schistosomiasis transmission remains at a low level in Nanjian County; however, the factors affecting the transmission of schistosomiasis have not been completed eliminated. The integrated schistosomiasis control strategy with an emphasis on the control of the source of S. japonicum infections requires to be reinforced to consolidate the control achievements.


Asunto(s)
Medición de Riesgo , Esquistosomiasis/transmisión , Animales , Bovinos , China/epidemiología , Ciudades , Estudios Transversales , Heces/parasitología , Humanos , Recuento de Huevos de Parásitos , Estudios Retrospectivos , Caracoles/parasitología
7.
Phys Rev Lett ; 125(11): 117205, 2020 Sep 11.
Artículo en Inglés | MEDLINE | ID: mdl-32975987

RESUMEN

Surface magnetism and its correlation with the electronic structure are critical to understanding the topological surface state in the intrinsic magnetic topological insulator MnBi_{2}Te_{4}. Here, using static and time resolved angle-resolved photoemission spectroscopy (ARPES), we find a significant ARPES intensity change together with a gap opening on a Rashba-like conduction band. Comparison with a model simulation strongly indicates that the surface magnetism on cleaved MnBi_{2}Te_{4} is the same as its bulk state. The inability of surface ferromagnetism to open a gap in the topological surface state uncovers the novel complexity of MnBi_{2}Te_{4} that may be responsible for the low quantum anomalous Hall temperature of exfoliated MnBi_{2}Te_{4}.

8.
Phys Rev Lett ; 125(3): 037202, 2020 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-32745422

RESUMEN

We present comprehensive electron spin resonance (ESR) studies of in-plane oriented single crystals of α-RuCl_{3}, a quasi-two-dimensional material with honeycomb structure, focusing on its high-field spin dynamics. The measurements were performed in magnetic fields up to 16 T, applied along the [110] and [100] directions. Several ESR modes were detected. Combining our findings with recent inelastic neutron- and Raman-scattering data, we identified most of the observed excitations. Most importantly, we show that the low-temperature ESR response beyond the boundary of the magnetically ordered region is dominated by single- and two-particle processes with magnons as elementary excitations. The peculiarities of the excitation spectrum in the vicinity of the critical field are discussed.

9.
Phys Rev Lett ; 124(16): 167204, 2020 Apr 24.
Artículo en Inglés | MEDLINE | ID: mdl-32383954

RESUMEN

The antiferromagnetic (AFM) compound MnBi_{2}Te_{4} is suggested to be the first realization of an AFM topological insulator. We report on inelastic neutron scattering studies of the magnetic interactions in MnBi_{2}Te_{4} that possess ferromagnetic triangular layers with AFM interlayer coupling. The spin waves display a large spin gap and pairwise exchange interactions within the triangular layer are long ranged and frustrated by large next-nearest neighbor AFM exchange. The degree of frustration suggests proximity to a variety of magnetic phases, potentially including skyrmion phases, which could be accessed in chemically tuned compounds or upon the application of symmetry-breaking fields.

10.
Nat Commun ; 11(1): 216, 2020 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-31924787

RESUMEN

The phenomena of antisymmetric magnetoresistance and the planar Hall effect are deeply entwined with ferromagnetism. The intrinsic magnetization of the ordered state permits these unusual and rarely observed manifestations of Onsager's theorem when time reversal symmetry is broken at zero applied field. Here we study two classes of ferromagnetic materials, rare-earth magnets with high intrinsic coercivity and antiferromagnetic pyrochlores with strongly-pinned ferromagnetic domain walls, which both exhibit antisymmetric magnetoresistive behavior. By mapping out the peculiar angular variation of the antisymmetric galvanomagnetic response with respect to the relative alignments of the magnetization, magnetic field, and electrical current, we experimentally distinguish two distinct underlying microscopic mechanisms: namely, spin-dependent scattering of a Zeeman-shifted Fermi surface and anomalous electron velocities. Our work demonstrates that the anomalous electron velocity physics typically associated with the anomalous Hall effect is prevalent beyond the ρxy(Hz) channel, and should be understood as a part of the general galvanomagnetic behavior.

11.
Proc Natl Acad Sci U S A ; 116(23): 11201-11206, 2019 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-30975759

RESUMEN

The magnetoresistance (MR) of a material is typically insensitive to reversing the applied field direction and varies quadratically with magnetic field in the low-field limit. Quantum effects, unusual topological band structures, and inhomogeneities that lead to wandering current paths can induce a cross-over from quadratic to linear MR with increasing magnetic field. Here we explore a series of metallic charge- and spin-density-wave systems that exhibit extremely large positive linear MR. By contrast to other linear MR mechanisms, this effect remains robust down to miniscule magnetic fields of tens of Oersted at low temperature. We frame an explanation of this phenomenon in a semiclassical narrative for a broad category of materials with partially gapped Fermi surfaces due to density waves.

12.
Zhonghua Bing Li Xue Za Zhi ; 47(12): 920-925, 2018 Dec 08.
Artículo en Chino | MEDLINE | ID: mdl-30522172

RESUMEN

Objective: To investigate the feasibility and value of interphase fluorescence in situ hybridization (FISH) in the pathological diagnosis, differential diagnosis and therapeutic assessment of B-cell lymphomas. Methods: The cohort included 604 cases of B-cell lymphoma which were collected at West China Hospital from May 2010 to December 2016.And all were subjected to interphase FISH using 11 break apart or fusion probes (MYC, bcl-2, bcl-6, IRF4, MYC/IgH, bcl-2/IgH, CCND1/IgH, IgH, API2/MALT1, p53/ATM, and D13S319/CEP12). Results: The median age of the 604 B-cell lymphoma patients was 47.7 (aged 2-90) years including 372 men and 232 women. All the cases was divided into 463 large B cell lymphomas(LBL) and 141 small B cell lymphomas, and the total interphase FISH positive rate was 59.8% (361/604). Among the 463 LBL, 12.5% (58/463), 9.5% (44/463) and 2.2% (10/463) of cases showed MYC, bcl-6 and bcl-2 gene rearrangements respectively; and 363 diffuse large B cell lymphoma (DLBCLs) were reclassified as germinal center B-cell (GCB) subtype (38.6%, 140/363) and non-GCB subtype (61.4%, 223/363) by Hans algorithm. The rearrangement rates in GCB and non-GCB DLBCL were 45.7%(64/140)and 21.5%(48/223; P=0.001), respectively. Compared to the non-GCB DLBCL, GCB DLBCL showed higher MYC and bcl-2 gene rearrangements (P=0.001). Eleven (2.4%, 11/463) cases had MYC and bcl-6 or bcl-2 gene rearrangement (double-hit lymphoma); one (0.2%, 1/463) case had MYC, bcl-6 and bcl-2 gene rearrangements (triple-hit lymphoma); two (0.4%, 2/463) cases had bcl-2 and bcl-6 gene rearrangements. MYC translocation and MYC/IgH fusion were detected in 94.2%(81/86) and 83.7%(72/86) cases of Burkitt lymphomas. IRF4 rearrangement was detected in two cases of IRF4+ LBCL. Genetic abnormalities were detected in 9/19, 100%(29/29), 30.8%(12/39) and 68.5%(37/54) cases of follicular lymphoma, mantle cell lymphoma, MALT lymphoma and chronic lymphocytic leukemia, respectively. Conclusions: Interphase FISH can rapidly and accurately detect the genetic changes in B-cell lymphomas. Different genetic changes are specifically valuable to the diagnosis, differential diagnosis, prognosis evaluation and treatment guidance of various B-cell lymphomas.


Asunto(s)
Genes bcl-2/genética , Genes myc/genética , Hibridación Fluorescente in Situ , Linfoma de Células B/genética , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Preescolar , China , Estudios de Factibilidad , Femenino , Reordenamiento Génico de Linfocito B , Humanos , Interfase , Linfoma de Células B/clasificación , Linfoma de Células B/patología , Linfoma de Células B Grandes Difuso/genética , Linfoma de Células B Grandes Difuso/patología , Masculino , Persona de Mediana Edad , Proteínas Proto-Oncogénicas c-bcl-6/genética , Translocación Genética , Adulto Joven
13.
J Phys Condens Matter ; 30(13): 135801, 2018 Apr 04.
Artículo en Inglés | MEDLINE | ID: mdl-29443004

RESUMEN

We report millimeter-sized Nd5Pb3 single crystals grown out of a Nd-Co flux. We experimentally study the magnetic order of Nd5Pb3 single crystals by measuring the anisotropic magnetic properties, electrical resistivity under high pressure up to 8 GPa, specific heat, and neutron single crystal diffraction. Two successive magnetic orders are observed at T N1 = 44 K and T N2 = 8 K. The magnetic cells can be described with a propagation vector [Formula: see text]. Cooling below T N1, Nd1 and Nd3 order forming ferromagnetic stripes along the b-axis, and the ferromagnetic stripes are coupled antiferromagnetically along the a-axis for the [Formula: see text] magnetic domain. Cooling below T N2, Nd2 orders antiferromagnetically to nearby Nd3 ions. All ordered moments align along the crystallographic c-axis. The magnetic order at T N1 is accompanied by a quick drop of electrical resistivity upon cooling and a lambda-type anomaly in the temperature dependence of specific heat. At T N2, no anomaly was observed in electrical resistivity but there is a weak feature in specific heat. The resistivity measurements under hydrostatic pressures up to 8 GPa suggest a possible phase transition around 6 GPa. Our first-principles band structure calculations show that Nd5Pb3 has the same electronic structure as does Y5Si3 which has been reported to be a one-dimensional electride with anionic electrons that do not belong to any atom. Our study suggests that R 5Pb3 (R = rare earth) can be a materials playground for the study of magnetic electrides. This deserves further study after experimental confirmation of the presence of anionic electrons.

14.
Phys Rev Lett ; 120(4): 047601, 2018 Jan 26.
Artículo en Inglés | MEDLINE | ID: mdl-29437453

RESUMEN

We have used a combination of ultrafast coherent phonon spectroscopy, ultrafast thermometry, and time-dependent Landau theory to study the inversion symmetry breaking phase transition at T_{c}=200 K in the strongly spin-orbit coupled correlated metal Cd_{2}Re_{2}O_{7}. We establish that the structural distortion at T_{c} is a secondary effect through the absence of any softening of its associated phonon mode, which supports a purely electronically driven mechanism. However, the phonon lifetime exhibits an anomalously strong temperature dependence that decreases linearly to zero near T_{c}. We show that this behavior naturally explains the spurious appearance of phonon softening in previous Raman spectroscopy experiments and should be a prevalent feature of correlated electron systems with linearly coupled order parameters.

15.
Phys Rev Lett ; 119(23): 237203, 2017 Dec 08.
Artículo en Inglés | MEDLINE | ID: mdl-29286699

RESUMEN

The insulating honeycomb magnet α-RuCl_{3} exhibits fractionalized excitations that signal its proximity to a Kitaev quantum spin liquid state; however, at T=0, fragile long-range magnetic order arises from non-Kitaev terms in the Hamiltonian. Spin vacancies in the form of Ir^{3+} substituted for Ru are found to destabilize this long-range order. Neutron diffraction and bulk characterization of Ru_{1-x}Ir_{x}Cl_{3} show that the magnetic ordering temperature is suppressed with increasing x, and evidence of zizag magnetic order is absent for x>0.3. Inelastic neutron scattering demonstrates that the signature of fractionalized excitations is maintained over the full range of x investigated. The depleted lattice without magnetic order thus hosts a spin-liquid-like ground state that may indicate the relevance of Kitaev physics in the magnetically dilute limit of RuCl_{3}.

16.
Phys Rev Lett ; 119(22): 227201, 2017 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-29286790

RESUMEN

We report measurements of optical absorption in the zigzag antiferromagnet α-RuCl_{3} as a function of temperature T, magnetic field B, and photon energy ℏω in the range ∼0.3-8.3 meV, using time-domain terahertz spectroscopy. Polarized measurements show that threefold rotational symmetry is broken in the honeycomb plane from 2 to 300 K. We find a sharp absorption peak at 2.56 meV upon cooling below the Néel temperature of 7 K at B=0 that we identify as the magnetic-dipole excitation of a zero-wave-vector magnon, or antiferromagnetic resonance (AFMR). With the application of B, the AFMR broadens and shifts to a lower frequency as long-range magnetic order is lost in a manner consistent with transitioning to a spin-disordered phase. From a direct, internally calibrated measurement of the AFMR spectral weight, we place an upper bound on the contribution to the dc susceptibility from a magnetic excitation continuum.

17.
Science ; 356(6335): 295-299, 2017 04 21.
Artículo en Inglés | MEDLINE | ID: mdl-28428420

RESUMEN

Strong electron interactions can drive metallic systems toward a variety of well-known symmetry-broken phases, but the instabilities of correlated metals with strong spin-orbit coupling have only recently begun to be explored. We uncovered a multipolar nematic phase of matter in the metallic pyrochlore Cd2Re2O7 using spatially resolved second-harmonic optical anisotropy measurements. Like previously discovered electronic nematic phases, this multipolar phase spontaneously breaks rotational symmetry while preserving translational invariance. However, it has the distinguishing property of being odd under spatial inversion, which is allowed only in the presence of spin-orbit coupling. By examining the critical behavior of the multipolar nematic order parameter, we show that it drives the thermal phase transition near 200 kelvin in Cd2Re2O7 and induces a parity-breaking lattice distortion as a secondary order.

18.
Phys Rev Lett ; 118(14): 147004, 2017 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-28430492

RESUMEN

The importance of electron-hole interband interactions is widely acknowledged for iron-pnictide superconductors with high transition temperatures (T_{c}). However, the absence of hole pockets near the Fermi level of the iron-selenide (FeSe) derived high-T_{c} superconductors raises a fundamental question of whether iron pnictides and chalcogenides have different pairing mechanisms. Here, we study the properties of electronic structure in the high-T_{c} phase induced by pressure in bulk FeSe from magnetotransport measurements and first-principles calculations. With increasing pressure, the low-T_{c} superconducting phase transforms into the high-T_{c} phase, where we find the normal-state Hall resistivity changes sign from negative to positive, demonstrating dominant hole carriers in contrast to other FeSe-derived high-T_{c} systems. Moreover, the Hall coefficient is enlarged and the magnetoresistance exhibits anomalous scaling behaviors, evidencing strongly enhanced interband spin fluctuations in the high-T_{c} phase. These results in FeSe highlight similarities with high-T_{c} phases of iron pnictides, constituting a step toward a unified understanding of iron-based superconductivity.

19.
J Phys Condens Matter ; 29(23): 235801, 2017 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-28443827

RESUMEN

Millimeter-sized PdAs2O6 single crystals are grown using the vapor transport technique. The magnetic order at [Formula: see text] K is studied by measuring magnetic properties, specific heat, and neutron single crystal diffraction. The anisotropic magnetic susceptibility and a metamagnetic transition observed in magnetic fields above 20 kOe suggest that the magnetic moment lies in the ab plane, consistent with the magnetic structure determined by neutron single crystal diffraction. Below 140 K, Pd2+ ions order ferromagnetically in the ab plane but antiferromagnetically along the crystallographic c axis. The ordered moment is refined to be 2.09(2) [Formula: see text]/Pd2+ using the fitted magnetic form factor of Pd2+ . A weak λ-type anomaly around T N was observed in specific heat and the magnetic entropy change across T N is 1.72 J mol-1 K.This small entropy change and the temperature dependence of the magnetic susceptibility support the presence of short range correlations in a wide temperature range [Formula: see text] 250 K. The comparison with SrRu2O6 suggests that the magnetic interactions in PdAs2O6 are dominated by Pd-(O-[Formula: see text]-O)-Pd super-superexchange and three dimensional despite the quasi-two-dimensional arrangement of magnetic ions. The comparison with NiAs2O6 suggests that increasing covalency of isostructural compounds is an effective approach to design and to discover new materials with higher magnetic order temperatures in the localized regime.

20.
J Mater Chem B ; 5(17): 3107-3110, 2017 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-32263708

RESUMEN

Dynamic tracking of nanoparticles in cells faces a big challenge due to fluorescence quenching. Here, the pH-switchable probe spiropyran (SP) was introduced into poly(ethylene glycol) (PEG) via atom transfer radical polymerization (ATRP) to construct expected "off-on" fluorescent nanoparticles. Strong red fluorescence was emitted to efficiently track nanoparticles in cells due to the isomerization of spiropyran to merocyanine in the endosome or lysosome.

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