942 research outputs found
Visualizing the elongated vortices in -Ga nanostrips
We study the magnetic response of superconducting -Ga via low
temperature scanning tunneling microscopy and spectroscopy. The magnetic vortex
cores rely substantially on the Ga geometry, and exhibit an unexpectedly-large
axial elongation with aspect ratio up to 40 in rectangular Ga nano-strips
(width 100 nm). This is in stark contrast with the isotropic circular
vortex core in a larger round-shaped Ga island. We suggest that the unusual
elongated vortices in Ga nanostrips originate from geometric confinement effect
probably via the strong repulsive interaction between the vortices and Meissner
screening currents at the sample edge. Our finding provides novel conceptual
insights into the geometrical confinement effect on magnetic vortices and forms
the basis for the technological applications of superconductors.Comment: published in Phys. Rev. B as a Rapid Communicatio
Quantized octupole acoustic topological insulator
The Berry phase associated with energy bands in crystals can lead to
quantized quantities, such as the quantization of electric dipole polarization
in an insulator, known as a one-dimensional (1D) topological insulator (TI)
phase. Recent theories have generalized such quantization from dipole to higher
multipole moments, giving rise to the discovery of multipole TIs, which exhibit
a cascade hierarchy of multipole topology at boundaries of boundaries: A
quantized octupole moment in the three-dimensional (3D) bulk can induce
quantized quadrupole moments on its two-dimensional (2D) surfaces, which then
produce quantized dipole moments along 1D hinges. The model of 2D quadrupole TI
has been realized in various classical structures, exhibiting zero-dimensional
(0D) in-gap corner states. Here we report on the realization of a quantized
octupole TI on the platform of a 3D acoustic metamaterial. By direct acoustic
measurement, we observe 0D corner states, 1D hinge states, 2D surface states,
and 3D bulk states, as a consequence of the topological hierarchy from octupole
moment to quadrupole and dipole moment. The critical conditions of forming a
nontrivial octupole moment are further demonstrated by comparing with another
two samples possessing a trivial octupole moment. Our work thus establishes the
multipole topology and its full cascade hierarchy in 3D geometries
Two-stage association study to identify the genetic susceptibility of a novel common variant of rs2075290 in ZPR1 to type 2 diabetes
The SNP of rs964184 in ZPR1 has recently been associated with type 2 diabetes mellitus (T2DM) in Japanese individuals. To comprehensively investigate the association of common variants in ZPR1 with T2DM in Han Chinese individuals, we designed a two-stage case-control study of 3,505 T2DM patients and 6,911 unrelated healthy Han Chinese individuals. A total of 24 single nucleotide polymorphisms (SNPs) were genotyped, and single-SNP association, imputation and gender-specific association analyses were performed. To increase the coverage of genetic markers, we implemented imputation techniques to extend the number of tested makers to 280. A novel SNP, rs2075290, and the previously reported SNP, rs964184, were significantly associated with T2DM in the two independent datasets, and individuals harboring the CC genotype of rs2075290 and GG genotype of rs964184 exhibited higher levels of fasting plasma glucose (FPG) and blood hemoglobin A1c (HbA1c) than individuals of other genotypes. Additionally, haplotype analyses indicated that two haplotype blocks containing rs2075290 or rs964184 were also significantly associated with T2DM. In summary, these results suggest that ZPR1 plays an important role in the etiology of T2DM, and this gene might be involved in abnormal glucose metabolism
DNA damage strength modulates a bimodal switch of p53 dynamics for cell-fate control
Background: The p53 pathway is differentially activated in response to distinct DNA damage, leading to alternative phenotypic outcomes in mammalian cells. Recent evidence suggests that p53 expression dynamics play an important role in the differential regulation of cell fate, but questions remain as to how p53 dynamics and the subsequent cellular response are modulated by variable DNA damage. Results: We identified a novel, bimodal switch of p53 dynamics modulated by DNA-damage strength that is crucial for cell-fate control. After low DNA damage, p53 underwent periodic pulsing and cells entered cell-cycle arrest. After high DNA damage, p53 underwent a strong monotonic increase and cells activated apoptosis. We found that the damage dose-dependent bimodal switch was due to differential Mdm2 upregulation, which controlled the alternative cell fates mainly by modulating the induction level and pro-apoptotic activities of p53. Conclusions: Our findings not only uncover a new mode of regulation for p53 dynamics and cell fate, but also suggest that p53 oscillation may function as a suppressor, maintaining a low level of p53 induction and pro-apoptotic activities so as to render cell-cycle arrest that allows damage repair.BiologySCI(E)10ARTICLEnull1
Defining the threshold: triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio’s non-linear impact on tubular atrophy in primary membranous nephropathy
BackgroundHyperlipidemia is common in primary membranous nephropathy (PMN) patients, and tubular atrophy (TA) is an unfavorable prognostic factor. However, the correlation between the triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio and TA is controversial. Therefore, our study aimed to investigate the association between the TG/HDL-C ratio and TA in PMN patients.MethodsWe conducted a cross-sectional study and collected data from 363 PMN patients at Shenzhen Second People’s Hospital from January 2008 to April 2023. The primary objective was to evaluate the independent correlation between the TG/HDL-C ratio and TA using binary logistic regression model. We used a generalized additive model along with smooth curve fitting and multiple sensitivity analyses to explore the relationship between these variables. Additionally, subgroup analyses were conducted to delve deeper into the results.ResultsOf the 363 PMN patients, 75 had TA (20.66%). The study population had a mean age of 46.598 ± 14.462 years, with 217 (59.78%) being male. After adjusting for sex, age, BMI, hypertension, history of diabetes, smoking, alcohol consumption, UPRO, eGFR, HB, FPG, and ALB, we found that the TG/HDL-C ratio was an independent risk factor for TA in PMN patients (OR=1.29, 95% CI: 1.04, 1.61, P=0.0213). A non-linear correlation was observed between the TG/HDL-C ratio and TA, with an inflection point at 4.25. The odds ratios (OR) on the left and right sides of this inflection point were 1.56 (95% CI: 1.17, 2.07) and 0.25 (95% CI: 0.04, 1.54), respectively. Sensitivity analysis confirmed these results. Subgroup analysis showed a consistent association between the TG/HDL-C ratio and TA, implying that factors such as gender, BMI, age, UPRO, ALB, hypertension and severe nephrotic syndrome had negligible effects on the link between the TG/HDL-C ratio and TA.ConclusionOur study demonstrates a non-linear positive correlation between the TG/HDL-C ratio and the risk of TA in PMN patients, independent of other factors. Specifically, the association is more pronounced when the ratio falls below 4.25. Based on our findings, it would be advisable to decrease the TG/HDL-C ratio below the inflection point in PMN patients as part of treatment strategies
Establishment of a sensitive UPLC-MS/MS method to quantify safinamide in rat plasma
A fast, simple, and sensitive ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was established for the quantification of safinamide in rat plasma. Plasma samples were treated with acetonitrile for protein precipitation, and diazepam was used as an internal standard (IS). The analytes were separated on an Acquity UPLC C18 (2.1 mm × 50 mm, 1.7 μm) chromatographic column with gradient elution using a mobile phase (0.1% formic acid-acetonitrile). Then, the eluates were detected by electrospray ionization (ESI) in positive ion mode. The analytes were quantified by multiple reaction monitoring (MRM) using the transition m/z 303.3→215.0 of safinamide and m/z 285.0→154.0 of IS. Safinamide had good linearity in the concentration range of 1.0–2000 ng/mL, and the lower limit of quantitation (LLOQ) was 1.0 ng/mL. The intra- and inter-day precision and accuracy of safinamide were less than 7.63%, while the average recovery rate was 92.98%–100.29%. The method was validated to be stable and had low noise, short chromatographic run time, wide linear range, small sample volumes, low sample injection volumes, and high sensitivity. Therefore, it can be used in pharmacokinetics and preclinical and clinical studies
Observation of vortex-string chiral modes in metamaterials
As a hypothetical topological defect in the geometry of spacetime, vortex
strings play a crucial role in shaping the clusters of galaxies that exist
today, and their distinct features can provide observable clues about the early
universe's evolution. A key feature of vortex strings is that they can interact
with Weyl fermionic modes and support topological chiral-anomaly states with
massless dispersions at the core of strings. To date, despite many attempts to
detect vortex strings in astrophysics or to emulate them in artificially
created systems, observation of these topological vortex-string chiral modes
remains experimentally elusive. Here we report the experimental observation of
such vortex-string chiral modes using a metamaterial system. This is
implemented by inhomogeneous perturbation of a Yang-monopole phononic
metamaterial. The measured linear dispersion and modal profiles confirm the
existence of topological modes bound to and propagating along the vortex string
with the chiral anomaly. Our work not only provides a platform for studying
diverse cosmic topological defects in astrophysics but also offers intriguing
device applications as topological fibres in signal processing and
communication techniques.Comment: 3 Figure
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