Ubiquitous coexisting electron-mode couplings in high-temperature cuprate superconductors.

In conventional superconductors, electron-phonon coupling plays a dominant role in generating superconductivity. In high-temperature cuprate superconductors, the existence of electron coupling with phonons and other boson modes and its role in producing high-temperature superconductivity remain unclear. The evidence of electron-boson coupling mainly comes from angle-resolved photoemission (ARPES) observations of [Formula: see text]70-meV nodal dispersion kink and [Formula: see text]40-meV antinodal kink. However, the reported results are sporadic and the nature of the involved bosons is still under debate. Here we report findings of ubiquitous two coexisting electron-mode couplings in cuprate superconductors. By taking ultrahigh-resolution laser-based ARPES measurements, we found that the electrons are coupled simultaneously with two sharp modes at [Formula: see text]70meV and [Formula: see text]40meV in different superconductors with different dopings, over the entire momentum space and at different temperatures above and below the superconducting transition temperature. These observations favor phonons as the origin of the modes coupled with electrons and the observed electron-mode couplings are unusual because the associated energy scales do not exhibit an obvious energy shift across the superconducting transition. We further find that the well-known "peak-dip-hump" structure, which has long been considered a hallmark of superconductivity, is also omnipresent and consists of "peak-double dip-double hump" finer structures that originate from electron coupling with two sharp modes. These results provide a unified picture for the [Formula: see text]70-meV and [Formula: see text]40-meV energy scales and their evolutions with momentum, doping and temperature. They provide key information to understand the origin of these energy scales and their role in generating anomalous normal state and high-temperature superconductivity.

The association between lower extremity function and cardiovascular diseases risk in older Chinese adults: Longitudinal evidence from a nationwide cohort.

BACKGROUND: Older adults in China are at a high risk of cardiovascular diseases (CVD), and impaired lower extremity function (LEF) is commonly observed in this demographic. This study aimed at assessing the association between LEF and CVD, thus providing valuable insights for clinical practice and public health policies. METHODS: A sample of 4,636 individuals was included from the China Health and Retirement Longitudinal Study (CHARLS) dataset. Logistic regression and cox proportional hazard regression model was utilized to study the association between LEF and CVD incidence. Cross-lagged panel models were utilized to investigate the potential causal association between LEF and CVD over time. RESULTS: Poor LEF was significantly associated with a higher risk of CVD in the total population [OR (95 % CI): 1.62 (1.27-2.05), P < 0.001]. Individuals with poor LEF demonstrated an increased risk of developing CVD [HR (95 % CI): 1.11 (1.02-1.23), P < 0.05], particularly stroke, compared to those with good LEF. And those with poor LEF had higher risks for heart disease [1.21 (1.00-1.45), P < 0.05] and stroke [1.98 (1.47-2.67), P < 0.001]. CONCLUSION: The results suggest the potential usefulness of the Short Physical Performance Battery (SPPB) for classifying stroke risk in older Chinese adults, which also suggested that preventing and/or improving LEF may be beneficial for reducing stroke incidence and promoting healthy aging for older adults.

Emergent normal fluid in the superconducting ground state of overdoped cuprates.

The microscopic mechanism for the disappearance of superconductivity in overdoped cuprates is still under heated debate. Here we use scanning tunneling spectroscopy to investigate the evolution of quasiparticle interference phenomenon in Bi2Sr2CuO6+δ over a wide range of hole densities. We find that when the system enters the overdoped regime, a peculiar quasiparticle interference wavevector with arc-like pattern starts to emerge even at zero bias, and its intensity grows with increasing doping level. Its energy dispersion is incompatible with the octet model for d-wave superconductivity, but is highly consistent with the scattering interference of gapless normal carriers. The gapless quasiparticles are mainly located near the antinodes and are independent of temperature, consistent with the disorder scattering mechanism. We propose that a branch of normal fluid emerges from the pair-breaking scattering between flat antinodal bands in the quantum ground state, which is the primary cause for the reduction of superfluid density and suppression of superconductivity in overdoped cuprates.

ARPES detection of superconducting gap sign in unconventional superconductors.

The superconducting gap symmetry is crucial in understanding the underlying superconductivity mechanism. Angle-resolved photoemission spectroscopy (ARPES) has played a key role in determining the gap symmetry in unconventional superconductors. However, it has been considered so far that ARPES can only measure the magnitude of the superconducting gap but not its phase; the phase has to be detected by other phase-sensitive techniques. Here we propose a method to directly detect the superconducting gap sign by ARPES. This method is successfully validated in a cuprate superconductor Bi2Sr2CaCu2O8+δ with a well-known d-wave gap symmetry. When two bands have a strong interband interaction, the resulted electronic structures in the superconducting state are sensitive to the relative gap sign between the two bands. Our present work provides an approach to detect the gap sign and can be applied to various superconductors, particularly those with multiple orbitals like the iron-based superconductors.

Correlating the charge-transfer gap to the maximum transition temperature in Bi2Sr2Can-1CunO2n+4+δ.

As the number of CuO2 layers, n, in each unit cell of a cuprate family increases, the maximum transition temperature (Tc,max) exhibits a universal bell-shaped curve with a peak at n = 3. The microscopic mechanism of this trend remains elusive. In this study, we used advanced electron microscopy to image the atomic structure of cuprates in the Bi2Sr2Can-1CunO2n+4+δ family with 1 ≤ n ≤ 9; the evolution of the charge-transfer gap size (Δ) with n can be measured simultaneously. We determined that the n dependence of Δ follows an inverted bell-shaped curve with the minimum Δ value at n = 3. The correlation between Δ, n, and Tc,max may clarify the origin of superconductivity in cuprates.

Moderate selenium mitigates hand grip strength impairment associated with elevated blood cadmium and lead levels in middle-aged and elderly individuals: insights from NHANES 2011-2014.

Background: Selenium (Se) has been reported to have an antagonistic effect on heavy metals in animals. Nevertheless, there is a lack of epidemiological research examining whether Se can mitigate the adverse effects of cadmium (Cd) and lead (Pb) on hand grip strength (HGS) in middle-aged and elderly individuals. Methods: This study used data from the 2011-2014 National Health and Nutrition Examination Survey (NHANES). HGS measurements were conducted by trained examiners with a dynamometer. Concentrations of Se, Cd, and Pb in blood were determined via inductively coupled plasma mass spectrometry. We employed linear regression, restricted cubic splines, and quantile g-computation (qgcomp) to assess individual and combined associations between heavy metals and HGS. The study also explored the potential influence of Se on these associations. Results: In both individual metal and multi-metal models adjusted for confounders, general linear regression showed Se's positive association with HGS, while Cd and Pb inversely related to it. At varying Se-Cd and Se-Pb concentrations, high Se relative to low Se can attenuate Cd and Pb's HGS impact. An inverted U-shaped correlation exists between Se and both maximum and combined HGS, with Se's benefit plateauing beyond approximately 200 µg/L. Stratified analysis by Se quartiles reveals Cd and Pb's adverse HGS effects diminishing as Se levels increase. Qgcomp regression analysis detected Se alleviating HGS damage from combined Cd and Pb exposure. Subsequent subgroup analyses identified the sensitivity of women, the elderly, and those at risk of diabetes to HGS impairment caused by heavy metals, with moderate Se supplementation beneficial in mitigating this effect. In the population at risk for diabetes, the protective role of Se against heavy metal toxicity-induced HGS reduction is inhibited, suggesting that diabetic individuals should particularly avoid heavy metal-induced handgrip impairment. Conclusion: Blood Cd and Pb levels are negatively correlated with HGS. Se can mitigate this negative impact, but its effectiveness plateaus beyond 200 µg/L. Women, the elderly, and those at risk of diabetes are more vulnerable to HGS damage from heavy metals. While Se supplementation can help, its protective effect is limited in high diabetes risk groups.

The Removal of Cr(VI) from Aqueous Solutions with Corn Stalk Biochar.

The discharge of wastewater containing hexavalent chromium (Cr(VI)) into the environment is very harmful to living things. Therefore, before effluent that contains Cr(VI) can be discharged into the environment, this toxin should be removed from the contaminated water. In this study, corn stalk biochar was investigated to evaluate the Cr(VI) removal efficiency from an aqueous solution. The effects of pH (2-10), biochar concentration (0.5 to 10 g/L), Cr(VI) concentration (10-500 mg/L), and contact time (10-1440 min) were studied. The actual experimental value of the Cr(VI) removal efficiency was 28.67%, largely consistent with the predicted model value of 29.31%, under the optimal conditions of a Cr(VI) concentration of 60 g/L, pH 4, contact time of 270 min, and a biochar concentration of 4.5 g/L. A significant interaction between the Cr(VI) concentration and pH was observed, along with significance in the interaction between Cr(VI) concentration and biochar concentration, which had a greater impact on the removal of Cr(VI). Biosorption onto corn stalk biochar is an affordable and economical adsorption process to treat wastewater contaminated with Cr(VI). The aim of this study is to provide data to serve as a basis for future studies on the use of raw agricultural waste to remove Cr(VI).

Spectroscopic evidence of superconductivity pairing at 83 K in single-layer FeSe/SrTiO3 films.

Single-layer FeSe films grown on the SrTiO3 substrate (FeSe/STO) have attracted much attention because of their possible record-high superconducting critical temperature (Tc) and distinct electronic structures. However, it has been under debate on how high its Tc can really reach due to the inconsistency of the results from different measurements. Here we report spectroscopic evidence of superconductivity pairing at 83 K in single-layer FeSe/STO films. By preparing high-quality single-layer FeSe/STO films, we observe strong superconductivity-induced Bogoliubov back-bending bands that extend to rather high binding energy ~ 100 meV by high-resolution angle-resolved photoemission measurements. They provide a new definitive benchmark of superconductivity pairing that is directly observed up to 83 K. Moreover, we find that the pairing state can be further divided into two temperature regions. These results indicate that either Tc as high as 83 K is achievable, or there is a pseudogap formation from superconductivity fluctuation in single-layer FeSe/STO films.

Effects of urban form on the urban heat island effect based on spatial regression model.

The urban heat island (UHI) effect is becoming more of a concern with the accelerated process of urbanization. However, few studies have examined the effect of urban form on land surface temperature (LST) especially from an urban planning perspective. This paper used spatial regression model to investigate the effects of both land use composition and urban form on LST in Wuhan City, China, based on the regulatory planning management unit. Landsat ETM+ image data was used to estimate LST. Land use composition was calculated by impervious surface area proportion, vegetated area proportion, and water proportion, while urban form indicators included sky view factor (SVF), building density, and floor area ratio (FAR). We first tested for spatial autocorrelation of urban LST, which confirmed that a traditional regression method would be invalid. A spatial error model (SEM) was chosen because its parameters were better than a spatial lag model (SLM). The results showed that urban form metrics should be the focus for mitigation efforts of UHI effects. In addition, analysis of the relationship between urban form and UHI effect based on the regulatory planning management unit was helpful for promoting corresponding UHI effect mitigation rules in practice. Finally, the spatial regression model was recommended to be an appropriate method for dealing with problems related to the urban thermal environment. Results suggested that the impact of urbanization on the UHI effect can be mitigated not only by balancing various land use types, but also by optimizing urban form, which is even more effective. This research expands the scientific understanding of effects of urban form on UHI by explicitly analyzing indicators closely related to urban detailed planning at the level of regulatory planning management unit. In addition, it may provide important insights and effective regulation measures for urban planners to mitigate future UHI effects.

Blockade of the activation of T cells around ß-cell by the targeted CTLA-4 Ig at the surface of ß-cell.

Diabetes mellitus affects 347 million people worldwide, and over 80 % of diabetes deaths occur in low- and middle-income countries. Type 1 diabetes (T1D) is characterized by the attacks of the body's own immune system on the pancreatic ß-cells. In this work, we present a new CTLA-4 Ig targeting at the surface of ß-cell and prepare it from Escherichia coli aiming at clearing activated T cells around ß-cells and avoiding all-round decline in systematic immunity. This fusion protein is composed of CTLA-4-Ig part and ß-cell-targeting part, with properties of the therapeutic effect of CTLA-4-Ig and selective binding to ß-cells. In preliminary biological activity assay, our results verified the feasibility of ß-cell-targeting strategy and its activity of CTLA-4-Ig part. The fusion protein recognizes and binds specifically to CD80(+) and CD86(+) cells as well as ß-cell, but not to control cells, displaying the potential to be used as a feasible and effective treatment of T1D with lessened side effect.