We reveal the cooperative effect of coherent and dissipative magnon-photon couplings in an open cavity magnonic system, which leads to nonreciprocity with a considerably large isolation ratio and ...flexible controllability. Furthermore, we discover unidirectional invisibility for microwave propagation, which appears at the zero-damping condition for hybrid magnon-photon modes. A simple model is developed to capture the generic physics of the interference between coherent and dissipative couplings, which accurately reproduces the observations over a broad range of parameters. This general scheme could inspire methods to achieve nonreciprocity in other systems.
We report dissipative magnon-photon coupling caused by the cavity Lenz effect, where the magnons in a magnet induce a rf current in the cavity, leading to a cavity backaction that impedes the ...magnetization dynamics. This effect is revealed in our experiment as level attraction with a coalescence of hybridized magnon-photon modes, which is distinctly different from level repulsion with mode anticrossing caused by coherent magnon-photon coupling. We develop a method to control the interpolation of coherent and dissipative magnon-photon coupling, and observe a matching condition where the two effects cancel. Our work sheds light on the so-far hidden side of magnon-photon coupling, opening a new avenue for controlling and utilizing light-matter interactions.
By engineering an anti-parity-time (anti-PT ) symmetric cavity magnonics system with precise eigenspace controllability, we observe two different singularities in the same system. One type of ...singularity, the exceptional point (EP), is produced by tuning the magnon damping. Between two EPs, the maximal coherent superposition of photon and magnon states is robustly sustained by the preserved anti-PT symmetry. The other type of singularity, arising from the dissipative coupling of two antiresonances, is an unconventional bound state in the continuum (BIC). At the settings of BICs, the coupled system exhibits infinite discontinuities in the group delay. We find that both singularities coexist at the equator of the Bloch sphere, which reveals a unique hybrid state that simultaneously exhibits the maximal coherent superposition and slow light capability.
The outbreak of Corona Virus Disease-2019 (COVID-19) has posed unprecedented pressure and threats to healthcare workers in Wuhan and the entire country.
To assess the effect of the COVID-19 outbreak ...on the sleep quality of healthcare workers in a children's healthcare centre in Wuhan.
A cross-sectional, anonymized, self-reported questionnaire survey was conducted at the Children's Healthcare Centre of Renmin Hospital, Wuhan University, Wuhan, China. The questionnaire consisted of three parts, including socio-demographic characteristics and COVID-19 epidemic-related factors, the Pittsburgh sleep quality index (PSQI), and Zung's self-rating anxiety scale (SAS) and self-rating depression scale (SDS).
In total, 47 out of 123 (38%) participants with PSQI scores > 7 were identified as having sleep disturbance. A logistic regression analysis showed that sleep disturbance was independently associated with being an only child (adjusted odds ratio (OR) and 95% confidence interval (CI) 3.40 (1.21-9.57), P < 0.05), exposure to COVID-19 patients (adjusted OR and 95% CI 2.97 (1.08-8.18), P < 0.05) and depression (adjusted OR and 95% CI 2.83 (1.10-7.27), P < 0.05).
We observed that, during the outbreak of COVID-19, sleep disturbance was highly prevalent among paediatric healthcare workers, and sleep disturbance was independently associated with being an only child, exposure to COVID-19 patients and depression. Therefore, more mental health services are required for front-line paediatric healthcare workers in Wuhan.
Although the first-order liquid-liquid phase transition (LLT) has been reported to exist in various systems (i.e., phosphorus, silicon, water, triphenyl phosphite, etc.), it is still one of the most ...challenging problems in the field of physical science. Recently, we found that this phenomenon occurs in the family of trihexyl(tetradecyl)phosphonium P
based ionic liquids (ILs) with different anions (Wojnarowska et al in Nat Commun 13:1342, 2022). To understand the molecular structure-property relationships governing LLT, herein, we examine ion dynamics of two other quaternary phosphonium ILs containing long alkyl chains in cation and anion. We found that IL with the anion containing branched -O-(CH
)
-CH
side chains does not reveal any signs of LLT, while IL with shorter alkyl chains in the anion brings a hidden LLT, i.e., it overlaps with the liquid-glass transition. Ambient pressure dielectric and viscosity measurements revealed a peculiar behavior of ion dynamics near T
for IL with hidden LLT. Moreover, high-pressure studies have shown that IL with hidden LLT has relatively strong pressure sensitivity compared to the one without first-order phase transition. At the same time, the former exposes the inflection point indicating the concave-convex character of logτ
(P) dependences.
In this study, we describe a methodology to examine dislocation loops in irradiated steels based on a combination of crystallographic information and g⋅b invisibility criteria. Dislocation loops in ...transmission electron microscope (TEM) images can be conveniently analyzed using this method. Through this analysis approach, dislocation loops in reduced activation ferritic/martensitic (RAFM) steels irradiated at 400°C have been examined. The predominant types of loops found in irradiated RAFM steels were 〈100〉{200} and 1/2〈111〉{111}. The size, density, and density anisotropy of these two types of dislocation loops were quantified. It was observed that the 〈100〉{200} loop density is more than twice that of 1/2〈111〉{111} loops. A large density anisotropy of 〈100〉{200} loops was identified.
Highlights • The difference between glucose–BSA and glycoaldehyde–BSA: effects on PC12 cells. • The protective effect mediated by GLP-1 receptor on AGE-induced neurotoxicity. • GLP-1 can reduce cell ...tau phosphorylation induced by high glucose or glucose–BSA. • GLP-1 regulated tau phosphorylation through a signaling pathway involving GSK-3β.
In candidate gene era, dozens of single-nucleotide polymorphisms (SNPs) within renin-angiotensin-aldosterone system (RAAS) have been reported to be significantly associated with hypertension. ...However, the unbiased genome-wide association studies (GWAS) rarely identified the SNPs within RAAS were associated with hypertension or blood pressure (BP) traits. In order to figure out whether genetic polymorphisms of RAAS are really associated with hypertension, we systemically searched the GWAS Catalogue and identified all the known RAAS genes and relevant diseases/traits. After data processing, we found that polymorphisms within REN, AGT, ACE2, CYP11B2, ATP6AP2 and HSD11B2 were not associated with any disease or trait. SNPs within ACE, AGTR1, AGTR2, MAS1, RENBP and NR3C2 were associated with other diseases or traits, but showed no direct connection with hypertension. The only SNP associated with a BP trait, systolic BP was rs17367504. However, it is located in the intronic region of MTHFR near many plausible candidate genes, including CLCN6, NPPA, NPPB and AGTRAP. Therefore, the effect of RAAS polymorphisms may have been overestimated during the 'candidate gene era'. In the time of 'precision medicine', the power of RAAS variants needs to be reconsidered when evaluating one's susceptibility of hypertension.
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