131 research outputs found
Variational Monte Carlo study of gapless spin liquid in the spin- XXZ antiferromagnetic model on the kagome lattice
By using the variational Monte Carlo technique, we study the spin- XXZ
antiferromagnetic model (with easy-plane anisotropy) on the kagome lattice. A
class of Gutzwiller projected fermionic states with a spin Jastrow factor is
considered to describe either spin liquids (with or symmetry) or
magnetically ordered phases (with or ). We
find that the magnetic states are not stable in the thermodynamic limit.
Moreover, there is no energy gain to break the gauge symmetry from to
within the spin-liquid states, as previously found in the Heisenberg
model. The best variational wave function is therefore the Dirac state,
supplemented by the spin Jastrow factor. Furthermore, a vanishing spin
gap is obtained at the variational level, in the whole regime from the to
the Heisenberg model.Comment: 7 pages, 7 figure
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Arctigenin alleviates ER stress via activating AMPK
Aim: To investigate the protective effects of arctigenin (ATG), a phenylpropanoid dibenzylbutyrolactone lignan from Arctium lappa L (Compositae), against ER stress in vitro and the underlying mechanisms. Methods: A cell-based screening assay for ER stress regulators was established. Cell viability was measured using MTT assay. PCR and Western blotting were used to analyze gene and protein expression. Silencing of the CaMKKÎČ, LKB1, and AMPKα1 genes was achieved by RNA interference (RNAi). An ATP bioluminescent assay kit was employed to measure the intracellular ATP levels. Results: ATG (2.5, 5 and 10 ÎŒmol/L) inhibited cell death and unfolded protein response (UPR) in a concentration-dependent manner in cells treated with the ER stress inducer brefeldin A (100 nmol/L). ATG (1, 5 and 10 ÎŒmol/L) significantly attenuated protein synthesis in cells through inhibiting mTOR-p70S6K signaling and eEF2 activity, which were partially reversed by silencing AMPKα1 with RNAi. ATG (1-50 ÎŒmol/L) reduced intracellular ATP level and activated AMPK through inhibiting complex I-mediated respiration. Pretreatment of cells with the AMPK inhibitor compound C (25 ÎŒmol/L) rescued the inhibitory effects of ATG on ER stress. Furthermore, ATG (2.5 and 5 ÎŒmol/L) efficiently activated AMPK and reduced the ER stress and cell death induced by palmitate (2 mmol/L) in INS-1 ÎČ cells. Conclusion: ATG is an effective ER stress alleviator, which protects cells against ER stress through activating AMPK, thus attenuating protein translation and reducing ER load
Pulmonary and aortic root translocation in the management of transposition of the great arteries with ventricular septal defect and left ventricular outflow tract obstruction
The boundary force exerted on spatial solitons in cylindrical strongly nonlocal media
We investigate the propagation of the spatial soliton in cylindrical strongly
nonlocal media by a novel method of image beam of light. The effect of the
boundary on the soliton acting as the dynamic force for the soliton steering is
equivalent to the force between the soliton beam and the image beam. The
trajectory of the soliton is analytically studied which is in good agreement
with the experimental results.Comment: 3 Pages, 3 figure
Numerical Simulation of LVAD Inflow Cannulas with Different Tip
The tip structure of LVAD inflow cannula is one of major factors to lead adverse events such as thrombosis and suction leading to obstruction. In this research, four kinds of tips that had been used in inflow cannulas were selected and designed. The flow field of the four inflow cannulas inserted into the apex of left ventricle (LV) was numerically computed by computational fluid dynamics. The flow behavior was analyzed in order to compare the blood compatibility and suction in left ventricle and cannulas after the inflow cannulas with different tips were inserted to the apex of LV. The results showed that the cannula tip structure affected the LVAD performance. Among these four cannulas, the trumpet-tipped inflow cannula owned the best performance in smooth flow velocity distribution without backflow or low-velocity flow so that it was the best in blood compatibility. Nevertheless, the caged tipped cannula was the worst in blood compatibility. And the blunt-tipped and beveled tipped inflow cannulas may obstruct more easily than trumpet and caged tipped inflow cannulas because of their shape. The study indicated that the trumpet tip was the most preferable for the inflow cannula of long-term LVAD
Dissecting the Genetic Architecture of Melon Chilling Tolerance at the Seedling Stage by Association Mapping and Identification of the Elite Alleles
Low temperature is an important abiotic stress that negatively affects morphological growth and fruit development in melon (Cucumis melo L.). Chilling stress at the seedling stage causes seedling injury and poor stand establishment, prolonging vegetative growth and delaying fruit harvest. In this study, association mapping was performed for chilling tolerance at the seedling stage on an expanded melon core collection containing 212 diverse accessions by 272 SSRs and 27 CAPSs. Chilling tolerance of the melon seedlings was evaluated by calculating the chilling injury index (CII) in 2016 and 2017. Genetic diversity analysis of the whole accession panel presented two main groups, which corresponded to the two subspecies of C. melo, melo, and agrestis. Both the subspecies were sensitive to chilling but with agrestis being more tolerant. Genome-wide association study (GWAS) was conducted, respectively, on the whole panel and the two subspecies, totally detecting 51 loci that contributed to 74 marker-trait associations. Of these associations, 35 were detected in the whole panel, 21 in melo, and 18 in agrestis. About half of the associations identified in the two subspecies were also observed in the whole panel, and seven associations were shared by both the subspecies. CMCT505_Chr.1 was repeatedly detected in different populations with high phenotypic contribution and could be a key locus controlling chilling tolerance in C. melo. Nine loci were selected for evaluation of the phenotypic effects related to their alleles, which identified 11 elite alleles contributing to seedling chilling tolerance. Four such alleles existed in both the subspecies and six in either of the two subspecies. Analysis of 20 parental combinations for their allelic status and phenotypic values showed that the elite alleles collectively contributed to enhancement of the chilling tolerance. Tagging the loci responsible for chilling tolerance may simultaneously favor dissecting the complex adaptability traits and elevate the efficiency to improve chilling tolerance using marker-assisted selection in melon
Boosting Superior Lithium Storage Performance of AlloyâBased Anode Materials via Ultraconformal Sb CoatingâDerived Favorable SolidâElectrolyte Interphase
Alloy materials such as Si and Ge are attractive as highâcapacity anodes for rechargeable batteries, but such anodes undergo severe capacity degradation during dischargeâcharge processes. Compared to the overâemphasized efforts on the electrode structure design to mitigate the volume changes, understanding and engineering of the solidâelectrolyte interphase (SEI) are significantly lacking. This work demonstrates that modifying the surface of alloyâbased anode materials by building an ultraconformal layer of Sb can significantly enhance their structural and interfacial stability during cycling. Combined experimental and theoretical studies consistently reveal that the ultraconformal Sb layer is dynamically converted to Li3Sb during cycling, which can selectively adsorb and catalytically decompose electrolyte additives to form a robust, thin, and dense LiFâdominated SEI, and simultaneously restrain the decomposition of electrolyte solvents. Hence, the Sbâcoated porous Ge electrode delivers much higher initial Coulombic efficiency of 85% and higher reversible capacity of 1046 mAh gâ1 after 200 cycles at 500 mA gâ1, compared to only 72% and 170 mAh gâ1 for bare porous Ge. The present finding has indicated that tailoring surface structures of electrode materials is an appealing approach to construct a robust SEI and achieve longâterm cycling stability for alloyâbased anode materials
Mitogen-activated Protein Kinase Kinase Antagonized Fas-associated Death Domain Proteinâmediated Apoptosis by Induced FLICE-inhibitory Protein Expression
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