105 research outputs found
Spin Transport Properties in Heisenberg Antiferromagnetic Spin Chains: Spin Current induced by Twisted Boundary Magnetic Fields
Spin transport properties of the one-dimensional Heisenberg antiferromagnetic
spin systems for both and S=1 are studied by applying twisted boundary
magnetic field. The spin current displays significantly different behavior of
the spin transport properties between and S=1 cases. For the spin-half
case, a London equation for the current and the detection of an alternating
electric field are proposed for the linear response regime. The correlation
functions reveal the spiral nature of spin configuration for both ground state
and the spinon excitations. For the spin-one chain otherwise, a kink is
generated in the ground state for the size is larger than the correlation
length, leading to an exponential dependence of spin current with respect to
the chains length. The midgap state emerges from the degenerate ground state
even for small boundary fields.Comment: 4 pages, 5 figure
Linking servant leadership to followers' thriving at work: self-determination theory perspective
Previous studies have confirmed that servant leadership has a positive impact on thriving at work, however, the psychological mechanism in this process has not been fully understood. Based on Self-Determination Theory, this study examines the mediating effect of basic psychological needs and the moderating effect of power distance on the relationship between servant leadership and followers' thriving at work. The results from the between-subject experimental design (Study 1) indicate that servant leadership can satisfy followers' three basic psychological needs. And the results from a questionnaire survey of 455 civil servants at two-time points (Study 2) indicate: (1) Servant leadership has a significantly positive impact on followers' thriving at work; (2) All three basic psychological needs satisfaction serve as a mediator in the relationship between servant leadership and followers' thriving at work; (3) Power distance negatively moderates the relationship between servant leadership and the satisfaction of three basic psychological needs, meaning that the lower on the power distance, the stronger the positive relationship between servant leadership and the satisfaction of three basic psychological needs; (4) Power distance negatively moderates the mediating effects of competence needs satisfaction and relatedness needs satisfaction in the relationship between servant leadership and followers' thriving at work, indicating that the lower on the power distance, the stronger the mediating effects. Our findings highlight the important role of servant leadership in fostering followers' thriving at work and explore the critical role of basic psychological needs satisfaction. This provides empirical evidence to further refine theories regarding thriving at work, and suggests that in order to promote employee thriving, it is important to guide leaders to reevaluating and repositioning their roles
Kondo Signatures of a Quantum Magnetic Impurity in Topological Superconductors
We study the Kondo physics of a quantum magnetic impurity in two-dimensional topological superconductors (TSCs), either intrinsic or induced on the surface of a bulk topological insulator, using a numerical renormalization group technique. We show that, despite sharing the p+ip pairing symmetry, intrinsic and extrinsic TSCs host different physical processes that produce distinct Kondo signatures. Extrinsic TSCs harbor an unusual screening mechanism involving both electron and orbital degrees of freedom that produces rich and prominent Kondo phenomena, especially an intriguing pseudospin Kondo singlet state in the superconducting gap and a spatially anisotropic spin correlation. In sharp contrast, intrinsic TSCs support a robust impurity spin doublet ground state and an isotropic spin correlation. These findings advance fundamental knowledge of novel Kondo phenomena in TSCs and suggest experimental avenues for their detection and distinction
Density-matrix renormalization group algorithm for non-Hermitian systems
A biorthonormal-block density-matrix renormalization group algorithm is
proposed to compute properties of non-Hermitian many-body systems, in which a
structured low-rank approximation to a non-Hermitian reduced density matrix is
implemented to fulfill the prerequisite for the biorthonormality of the
renormalization transformation and to optimally construct a saved space as
well. A redundancy assigned to the saved space of the reduced density matrix is
exploited to reduce a condition number resulting from the left and right
transformation matrices, thus ensuring the numerical stability of the
renormalization procedure. The algorithm is successfully applied to an
interacting fermionic Su-Schrieffer-Heeger model with both nonreciprocal
hoppings and staggered complex chemical potential, exhibiting novel many-body
phenomena in the ground-state phase diagram.Comment: 5+9 pages, 3+2 figure
Radiofrequency ablation can reverse the structural remodeling caused by frequent premature ventricular contractions originating from the right ventricular outflow tract even in a normal heart
OBJECTIVE: The aim of this study was to evaluate whether frequent premature ventricular contractions originating from the right ventricular outflow tract remodel the cardiac structure and function in patients with a âseemingly normal heartâ and whether radiofrequency ablation can reverse this remodeling. METHODS: Sixty-eight patients with idiopathic frequent premature ventricular contractions originating from the right ventricular outflow tract and normal heart structure and function were enrolled in this study. The patients were divided into three groups according to the therapeutic method: radiofrequency ablation group (24 cases), anti-arrhythmia drug group (26 cases), and control group (18 cases without any treatment). Clinical Registration number: ChiCTR-ONRC-12002834 RESULTS: The basic patient characteristics were comparable between the three groups, except for the premature ventricular contraction rate, which was significantly lower in the control group. After six months of follow up, the premature ventricular contraction rate was significantly reduced in the radiofrequency ablation group, which was accompanied by a significant decrease in the following cardiac cavity inner diameters, as determined by echocardiography: right atrium (33.33±3.78 vs. 30.05±2.60 mm, p = 0.001), right ventricle (23.24±2.40 vs. 21.05±2.16 mm, p = 0.020), and left ventricle (44.76±4.33 vs. 41.71±3.44 mm, p = 0.025). These results were similar in the anti-arrhythmia drug group, although this group exhibited a smaller extent of change (right atrium: 33.94±3.25 vs. 31.27±3.11 mm, p = 0.024; right ventricle: 22.97±3.09 vs. 21.64±2.33 mm, p = 0.049; left ventricle: 45.92±6.38 vs. 43.84±5.67 mm, p = 0.039), but not in the control group (p>;0.05). There was a tendency toward improvement in the cardiac functions in both the radiofrequency ablation and anti-arrhythmia drug groups. However, these differences were not statistically significant (p>;0.05). CONCLUSIONS: These results indicate that radiofrequency ablation can potentially reverse the cardiac remodeling caused by frequent premature ventricular contractions even in structurally normal hearts and that frequent premature ventricular contractions should be abated even in structurally normal hearts
A single nucleotide variant in HNF-1ÎČ is associated with maturity-onset diabetes of the young in a large Chinese family
Background:
Maturity-onset diabetes of the young (MODY) is a heterogeneous entity of monogenic disorders characterized by autosomal dominant inheritance. Eleven genes were related, including HNF4α, GCK, HNF1α, IPF1, and HNF-1ÎČ, and various mutations are being reported.
Methods:
To help the overall understanding of MODY-related pathologic mutations, we studied a large MODY family found in 2012, in Shandong, China, which contained 9 patients over 3 generations. DNA was extracted from the periphery blood samples of (i) 9 affected members, (ii) 17 unaffected members, and (iii) 1000 healthy controls. Three pooled samples were obtained by mixing equal quantity of DNA of each individual within the each group. Totally 400 microsatellite markers across the whole genome were genotyped by capillary electrophoresis. The known MODY-related gene near the identified marker was sequenced to look for putative risk variants.
Results:
Allelic frequency of marker D17S798 on chromosome 17q11.2 were significantly different (P<0.001) between the affected vs. unaffected members and the affected vs. healthy controls, but not between the unaffected members vs. healthy controls. MODY5-related gene, hepatocyte nuclear factor-1ÎČ (HNF-1ÎČ) on 17q12 near D17S798 became the candidate gene. A single nucleotide variant (SNV) of C77T in the non-coding area of exon 1 of HNF-1ÎČ was found to be related to MODY5.
Conclusion:
This novel SNV of HNF-1ÎČ contributes to the diabetes development in the family through regulating gene expression most likely. The findings help presymptomatic diagnosis, and imply that mutations in the non-coding areas, as well as in the exons, play roles in the etiology of MODY
Immune Checkpoint Axes Are Dysregulated in Patients With Alcoholic Hepatitis
Alcoholic hepatitis (AH) is a severe inflammatory liver disease that develops in some heavy drinkers. The immune system in patients with AH is hyperactive and yet dysfunctional. Here, we investigated whether this immuneâdysregulated state is related to the alcoholic impact on immune checkpoints (ICPs). We used multiplex immunoassays and enzymeâlinked immunosorbent assay to quantify plasma levels of 18 soluble ICPs (sICPs) from 81 patients with AH, 65 heavy drinkers without liver diseases (HDCs), and 39 healthy controls (HCs) at baseline, 33 patients with AH and 32 HDCs at 6âmonth followâup, and 18 patients with AH and 29 HDCs at 12âmonth followâup. We demonstrated that baseline levels of 6 sICPs (soluble Tâcell immunoglobulin and mucin domain 3 [sTIMâ3], soluble cluster of differentiation [sCD]27, sCD40, soluble Tollâlike receptorâ2 [sTLRâ2], soluble herpesvirus entry mediator [sHVEM], and soluble lymphotoxinâlike inducible protein that competes with glycoprotein D for herpes virus entry on T cells [sLIGHT]) were upâregulated, while 11 sICPs (soluble Bâ and Tâlymphocyte attenuator [sBTLA], sCD160, soluble cytotoxic Tâlymphocyteâassociated protein 4 [sCTLAâ4], soluble lymphocyteâactivation gene 3 [sLAGâ3], soluble programmed death 1 [sPDâ1], sPD ligand 1 [sPDâL1], sCD28, soluble glucocorticoidâinduced tumor necrosis factor receptorârelated protein [sGITR], sGITR ligand [sGITRL], sCD80, and inducible Tâcell costimulator [sICOS]) were downâregulated in patients with AH compared to HDCs. The upâregulated sICPs except sLIGHT and downâregulated sCD80, sCD160, sCTLAâ4, and sLAGâ3 correlated positively or negatively with AH disease severity, bacterial translocation, and inflammatory factors. At followâup, abstinent patients with AH still had higher levels of several sICPs compared to HDCs. We also compared expression of 10 membraneâbound ICPs (mICPs) on peripheral blood mononuclear cells (PBMCs) from patients with AH and HCs by flow cytometry and found that several mICPs were dysregulated on blood cells from patients with AH. The function and regulation of sICPs and mICPs were studied using PBMCs from patients with AH and HCs. Recombinant sHVEM affected tumor necrosis factor (TNF)âα and interferonâÎł production by T cells from patients with AH and HCs. Conclusion: Both sICPs and mICPs were dysregulated in patients with AH, and alcohol abstinence did not fully reverse these abnormalities. The HVEM axis plays a role in regulating Tâcell function in patients with AH
SLIT2/ROBO1-miR-218-1-RET/PLAG1: a new disease pathway involved in Hirschsprung\u27s disease.
Hirschsprung\u27s disease (HSCR) is a rare congenital disease caused by impaired proliferation and migration of neural crest cells. We investigated changes in expression of microRNAs (miRNAs) and the genes they regulate in tissues of patients with HSCR. Quantitative real-time PCR and immunoblot analyses were used to measure levels of miRNA, mRNAs, and proteins in colon tissues from 69 patients with HSCR and 49 individuals without HSCR (controls). Direct interactions between miRNAs and specific mRNAs were indentified in vitro, while the function role of miR-218-1 was investigated by using miR-218 transgenic mice. An increased level of miR-218-1 correlated with increased levels of SLIT2 and decreased levels of RET and PLAG1 mRNA and protein. The reductions in RET and PLAG1 by miR-218-1 reduced proliferation and migration of SH-SY5Y cells. Overexpression of the secreted form of SLIT2 inhibited cell migration via binding to its receptor ROBO1. Bowel tissues from miR-218-1 transgenic mice had nerve fibre hyperplasia and reduced numbers of gangliocytes, compared with wild-type mice. Altered miR-218-1 regulation of SLIT2, RET and PLAG1 might be involved in the pathogenesis of HSCR
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