Spin-glass ground state in a triangular-lattice compound YbZnGaO4_4

We report on comprehensive results identifying the ground state of a triangular-lattice structured YbZnGaO$_4$ to be spin glass, including no long-range magnetic order, prominent broad excitation continua, and absence of magnetic thermal conductivity. More crucially, from the ultralow-temperature a.c. susceptibility measurements, we unambiguously observe frequency-dependent peaks around 0.1 K, indicating the spin-glass ground state. We suggest this conclusion to hold also for its sister compound YbMgGaO$_4$, which is confirmed by the observation of spin freezing at low temperatures. We consider disorder and frustration to be the main driving force for the spin-glass phase.Comment: Version as accepted to PR

Tunable positions of Weyl nodes via magnetism and pressure in the ferromagnetic Weyl semimetal CeAlSi

The noncentrosymmetric ferromagnetic Weyl semimetal CeAlSi with simultaneous space-inversion and time-reversal symmetry breaking provides a unique platform for exploring novel topological states. Here, by employing multiple experimental techniques, we demonstrate that ferromagnetism and pressure can serve as efficient parameters to tune the positions of Weyl nodes in CeAlSi. At ambient pressure, a magnetism-facilitated anomalous Hall/Nernst effect (AHE/ANE) is uncovered. Angle-resolved photoemission spectroscopy (ARPES) measurements demonstrated that the Weyl nodes with opposite chirality are moving away from each other upon entering the ferromagnetic phase. Under pressure, by tracing the pressure evolution of AHE and band structure, we demonstrate that pressure could also serve as a pivotal knob to tune the positions of Weyl nodes. Moreover, multiple pressure-induced phase transitions are also revealed. These findings indicate that CeAlSi provides a unique and tunable platform for exploring exotic topological physics and electron correlations, as well as catering to potential applications, such as spintronics

Reduction in the exposure risk of farmer from e-waste recycling site following environmental policy adjustment: a regional scale view of PAHs in paddy fields

Farmland contamination by polycyclic aromatic hydrocarbons (PAHs) has drawn increasing attention across China with enhanced regulations and environmental policies proposed by government to protect soil environment safety. As the informal electronic waste (e-waste) dismantling activities were forbidden under recent environmental regulation, this study compared levels, compositions, spatial distributions, human health risks of PAHs in paddy soil within the vicinity of an e-waste recycling area in southeastern China, with 129 and 150 soil samples collected in 2011 and 2016, respectively. The soil contamination was dominated with high molecular weight PAHs. The mean concentration of EPA 16 PAHs decreased from 590.4 ± 337.2 μg kg in 2011 to 407.3 ± 232.2 μg kg in 2016. Distribution maps of soil PAHs concentration displayed the temporal change in spatial. Principal component analysis together with diagnostic ratios revealed the combustion of biomass and coal in industrial and unregulated e-waste dismantling were the main sources of PAHs in the study area. Both deterministic and probabilistic assessments demonstrated reduced exposure risk for farmers from 2011 to 2016. Sensitivity analysis revealed that exposure frequency (EF) is the most influential parameter for the total variance in the risk assessment model. This study implied that the more stringent environmental policy and regulation can lead reductions in soil contamination with PAHs. [Abstract copyright: Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.

Revealing Landscape of Competing Endogenous RNA Networks in Sepsis-Induced Cardiovascular Diseases

Cardiovascular dysfunction induced by sepsis is one of the most common phenotypes of cardiovascular diseases (CVDs), which is closely related to the high mortality of sepsis and is an urgent health problem to be solved worldwide. Unfortunately, the exact pathogenesis and pathophysiology of sepsis-induced cardiovascular dysfunction are not clear. As a research hotspot in recent years, competing endogenous RNA (ceRNA) networks are involved in the modulation of the pathophysiological progression of many diseases, including sepsis-related CVDs. Both long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs) can specifically bind to microRNAs (miRNAs) as ceRNAs to target messenger RNAs (mRNAs), forming a ceRNA network composed of lncRNA/circRNA-miRNA-mRNA. This review demonstrates the potential regulatory mechanism of the ceRNA networks in sepsis-induced cardiovascular toxicity, hoping to provide novel therapeutic strategies and monitoring targets for sepsis-related CVDs

Melt Memory Effect in Polyethylene Random Terpolymer with Small Amount of 1-Octene and 1-Hexene Co-Units: Non-Isothermal and Isothermal Investigations

Homo-polymers of reasonable molecular weight relax very fast in the molten state. Starting from a semi-crystalline structure, when the homo-polymer is heated up to a temperature higher than its nominal melting temperature, it relaxes quickly into a homogenous molten state. The following crystallization temperature during cooling remains constant irrespective of the melt temperature. However, the situation is evidently different in copolymers. A phenomenon named the crystallization melt memory effect denotes an increased crystallization rate during cooling after a polymer was melted at different temperatures, which is often observed. The melt temperature can be even higher than the equilibrium melting temperature of the corresponding polymer crystals. In this work, we investigated such memory effect in a polyethylene random terpolymer with a small fraction of 1-octene and 1-hexene co-units using differential scanning calorimetry techniques. Both non-isothermal and isothermal protocols were employed. In non-isothermal tests, a purposely prepared sample with well defined thermal history (the sample has been first conditioned at 200 °C for 5 min to eliminate the thermal history and then cooled down to −50 °C) was melted at different temperatures, followed by a continuous cooling at a constant rate of 20 °C/min. Peak crystallization temperature during cooling was taken to represent the crystallization rate. Whereas, in isothermal tests, the same prepared sample with well defined thermal history was cooled to a certain crystallization temperature after being melted at different temperatures. Here, time to complete the isothermal crystallization was recorded. It was found that the results of isothermal tests allowed us to divide the melt temperature into four zones where the features of the crystallization half time change