The performance of single‐atom electrocatalysts usually suffers from attenuation due to high energy states, especially in harsh environments. Therefore, as high‐efficiency electrocatalysts for ...hydrogen reduction reaction (HER), supported metal nanoclusters (NCs) with maximum metal atom efficiency are promising, yet the genuine mechanism involving rational orbital modulation is still arguable. Herein, the conjugating effect between electron‐donor boron (B)‐tethering engineering and iridium (Ir) that facilitates the electron capture of Ir atoms is explored, achieving highly dispersive Ir‐NCs confined in N, B co‐doped defective carbon (Ir@NBD‐C). The Ir@NBD‐C catalyst achieves displays remarkable high activity for HER in a pH‐universal range, in particular, with an ultralow overpotential of 7 mV (10 mA cm−2), high mass activity of 652.2 A gIr−1, and turnover frequency (TOF) of 1.90 H2 S−1 (100 mV) in 1.0 m KOH, outperforming almost all state‐of‐the‐art HER electrocatalysts. Operando characterizations and theoretical calculations unveil that the outstanding catalytic activity can attribute to the optimal binding to hydrogen intermediate species (H*) derived from the tunable and favorable electronic structure of the Ir site through the tethering of B heteroatoms. Undoubtedly, this work brings new insight into the design of catalysts with high intrinsic activity and thermodynamic stability.
Synergistic tethering of electron‐donor (B)/acceptor (N) heteroatoms regulates the electronic structure of Ir nanoclusters, resulting in high catalytic activity and optimal adsorption energy of hydrogen intermediate (H*) in HER.
The shell of Artemia resting egg, which is a delicate multilayered envelope surrounding the inside diapause embryo, plays an important role in the survival strategy of Artemia. To date, the ...ultrastructure of resting eggshell has been studied for only handful populations, and knowledge about the diversity of shell structure is still limited. In this paper, resting eggs from 13 Artemia populations were studied by transmission electron microscopy. Results show that the basic configuration of resting eggshell is quite conservative, but variations are not uncommon in the fine ultrastructure of each main layer of the shell (e.g., the shape and distribution of the radially oriented pores in the cortical layer; the size, number and arrangement of chambers in the alveolar layer; and the development state of outer cuticular membrane OCM). The ultrastructural variation of eggshell seems not to be linked with species and reproductive mode of Artemia. Resting eggs from very high habitats (4300+ m above sea level a.s.l.) on Qinghai–Tibet Plateau and certain tropical salterns have a hypoplastic OCM, which may be related to the adaptation to habitat conditions such as low oxygen concentration.
Research Highlights
Comparative study on resting eggs from 13 Artemia populations reveals high diversity in the fine structure of eggshell.
Resting eggs from very high (4300+ m a.s.l.) habitats commonly have a hypoplastic OCM.
This picture shows the variation in the ultrastructure of the shell of Artemia resting eggs.
MicroRNAs (miRNAs) are a class of small single-stranded and highly conserved non-coding RNAs, which are closely linked to cardiac disorders such as myocardial infarction (MI), cardiomyocyte ...hypertrophy, and heart failure. A growing number of studies have demonstrated that miRNAs determine the fate of the heart by regulating cardiac cell death and regeneration after MI. A deep understanding of the pathophysiology of miRNA dependent regulatory pathways in these processes is required. The role of miRNAs as diagnostic, prognostic, and therapeutic targets also needs to be explored in order to utilize them in clinical settings. This review summarizes the role of miRNAs in myocardial infarction and focuses mainly on their influence on cardiomyocyte regeneration and cell death including apoptosis, necrosis, and autophagy. In addition, the targets of pro- and anti-MI miRNAs are comparatively described. In particular, the possibilities of miRNA-based diagnostic and therapeutic strategies for myocardial infarction are discussed in this review.
Binary metal oxide stannate (M
SnO
; M = Zn, Mn, Co, etc.) structures, with their high theoretical capacity, superior lithium storage mechanism and suitable operating voltage, as well as their dual ...suitability for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs), are strong candidates for next-generation anode materials. However, the capacity deterioration caused by the severe volume expansion problem during the insertion/extraction of lithium or sodium ions during cycling of M
SnO
-based anode materials is difficult to avoid, which greatly affects their practical applications. Strategies often employed by researchers to address this problem include nanosizing the material size, designing suitable structures, doping with carbon materials and heteroatoms, metal-organic framework (MOF) derivation and constructing heterostructures. In this paper, the advantages and issues of M
SnO
-based materials are analyzed, and the strategies to solve the issues are discussed in order to promote the theoretical work and practical application of M
SnO
-based anode materials.
...developmental stages of B cells, that is B220+CD43+IgM−IgD− (pro‐B), B220+CD43−IgM−IgD− (pre‐B), B220+CD43−IgM+IgD− (immature B) and B220+CD43−IgM+IgD+ (mature B), were detected in mouse BM, ...intestinal lamina propria (LPL) and Peyer's patches (PPs) by flow cytometry. ...the expression levels of CD40, CD80 and MHC‐Ⅱ on B cells were detected in mouse SPL, MLN and PPs. ...we examined the Secretory Immunoglobulin A (SIgA) level in intestinal lavage fluid and serum IgM, IgA and Immunoglobulin G (IgG) by ELISA. ...LGG intervention can promote the development and maturation of B lymphocytes, enhance the activation and antigen‐presentation ability of B lymphocytes, and regulate the secretion of immunoglobulin by B lymphocytes. ...LGG can regulate the mucosal immunity and humoural immunity of mice.
Bird-mediated dispersal of resting eggs is the main mechanism for Artemia dispersal among catchments. The bisexual populations of Artemia urmiana species complex, which is here considered to be a ...collection of Artemia genetically close to the so-called "Western Asian Lineage", are mostly distributed in central and western Asia (i.e., in regions falling into the Central Asian Flyway of migratory birds) and live in diversified habitats. Little is known about the genetic relationships among these populations. Aiming to understand the population genetic characteristics and the roles of migratory birds on the dispersal and gene flow of this Artemia group, we evaluated the genetic diversity, genetic differentiation, and gene flow among 14 populations, with their altitudes ranging from 540 to 4870 m above sea level, using 13 microsatellite markers. Almost all populations exhibited high genetic diversity and heterozygote excess, which may be a consequence of combined effects of dispersal and hybridization. The global genetic differentiation (F
) value was 0.092, the pairwise F
values were 0.003-0.246. Discriminant analysis of principal components identified three genetic clusters, consisting of Urmia Lake (Iran), Zhundong (Xinjiang, China), and 12 Qinghai-Tibet Plateau populations, respectively. The among-population genetic differentiation seems to be a consequence of isolation by distance and adaptation to diversified habitats induced by altitudinal gradient. Historical gene flows are asymmetrical, and show an evolutionary source-sink dynamics, with Jingyu Lake (Xinjiang, China) population being the major source. These results support our hypothesis that in Qinghai-Tibet Plateau and surrounding areas the bird-mediated dispersal of Artemia may be biased towards from north to south and/or from higher altitude to lower altitude.
To determine the change in refractive error and the incidence of myopia among school-aged children in the Yongchuan District of Chongqing City, Western China.
A population-based cross-sectional ...survey was initially conducted in 2006 among 3070 children aged 6 to 15 years. A longitudinal follow-up study was then conducted 5 years later between November 2011 and March 2012. Refractive error was measured under cycloplegia with autorefraction. Age, sex, and baseline refractive error were evaluated as risk factors for progression of refractive error and incidence of myopia.
Longitudinal data were available for 1858 children (60.5%). The cumulative mean change in refractive error was -2.21 (standard deviation SD, 1.87) diopters (D) for the entire study population, with an annual progression of refraction in a myopic direction of -0.43 D. Myopic progression of refractive error was associated with younger age, female sex, and higher myopic or hyperopic refractive error at baseline. The cumulative incidence of myopia, defined as a spherical equivalent refractive error of -0.50 D or more, among initial emmetropes and hyperopes was 54.9% (95% confidence interval CI, 45.2%-63.5%), with an annual incidence of 10.6% (95% CI, 8.7%-13.1%). Myopia was found more likely to happen in female and older children.
In Western China, both myopic progression and incidence of myopia were higher than those of children from most other locations in China and from the European Caucasian population. Compared with a previous study in China, there was a relative increase in annual myopia progression and annual myopia incidence, a finding which is consistent with the increasing trend on prevalence of myopia in China.
Organic photovoltaics (OPVs) have recently achieved efficiencies of over 19% and are well underway toward practical applications. However, issues concerning operational stability remain a major ...challenge ahead of OPV commercialization. Here, when replacing the conventional hole‐transporting layer PEDOT:PSS with a self‐assembled monolayer of 2‐(3,6‐dichloro‐9H‐carbazol‐9‐yl)ethylphosphonic acid (3,6‐Cl‐2PACz) or 2‐(4,5‐dichloro‐9H‐carbazol‐9‐yl)ethylphosphonic acid (4,5‐Cl‐2PACz) it is found that the T80 lifetime of PM6:BTP‐eC9‐based devices can be improved from ~100 to ~470 and over 800 h, respectively. The power conversion efficiency is also improved from 17.29% to 18.17% and 18.67%, respectively. The improved performance and prolonged photostability in 4,5‐Cl‐2PACz‐based devices stem from the stabilized vertical distribution of donor and acceptor components, reducing the energetic disorder and thus alleviating non‐radiative recombination losses. It is further found that the surface energy of 4,5‐Cl‐2PACz‐modified substrates stays constant under prolonged illumination due to the improved intrinsic photostability of 4,5‐Cl‐2PACz, supporting the robust active layer morphology. Applying 4,5‐Cl‐2PACz in a ternary device of PM6:BTP‐eC9:L8‐BO‐F delivered an efficiency of 19.05% and a T80 lifetime over 1140 h.
The 4,5‐Cl‐2PACz self‐assembled monolayer has an improved intrinsic photostability compared to that of 3,6‐Cl‐2PACz, supporting the stabilized vertical distribution of donor and acceptor components, reducing the energetic disorder, alleviating non‐radiative recombination losses, and thus prolonging the T80 lifetime of devices from ~470 to over 760 h for binary and over 1140 h for ternary devices under continuous illumination.
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