A protein‐sized (ca. 4.2×4.2×3.6 nm3) non‐biologically derived molecule {Nb288O768(OH)48(CO3)12} (Nb288) containing up to 288 niobium atoms has been obtained, which is by far the largest and the ...highest nuclearity polyoxoniobate (PONb). Particularly, in terms of metal nuclearity number, Nb288 is the second largest cluster so far reported in classic polyoxometalate chemistry (V, Mo, W, Nb, and Ta). Nb288 can be described as a giant windmill‐like cluster aggregate of six nanoscale high‐nuclearity PONb units {Nb47O128(OH)6(CO3)2} (Nb47) joined together by six additional Nb ions. Interestingly, the 47‐nuclearity Nb47 units generated in situ can be isolated and bridged by copper complexes to form an inorganic–organic hybrid three‐dimensional PONb framework, which exhibits effective catalytic activity for hydrolyzing nerve agent simulant of dimethyl methylphosphonate. The unique Nb47 cluster also provides a new type of topology to very limited family of Nb‐O clusters.
Friendly niobium giant: An unprecedentedly huge polyoxoniobate (PONb) with as many as 288 Nb centers has been made. This is by far the largest PONb and the second highest nuclearity polyoxometalate reported to date. It incorporates a unique 47‐nuclearity PONb building unit formed in situ, which can be stabilized by metal complexes to form an extended PONb framework with the capability of hydrolyzing dimethyl methylphosphonate.
Perivascular adipose tissue (PVAT), the adipose tissue that surrounds most of the vasculature, has emerged as an active component of the blood vessel wall regulating vascular homeostasis and ...affecting the pathogenesis of atherosclerosis. Although PVAT characteristics resemble both brown and white adipose tissues, recent evidence suggests that PVAT develops from its own distinct precursors implying a closer link between PVAT and vascular system. Under physiological conditions, PVAT has potent anti-atherogenic properties mediated by its ability to secrete various biologically active factors that induce non-shivering thermogenesis and metabolize fatty acids. In contrast, under pathological conditions (mainly obesity), PVAT becomes dysfunctional, loses its thermogenic capacity and secretes pro-inflammatory adipokines that induce endothelial dysfunction and infiltration of inflammatory cells, promoting atherosclerosis development. Since PVAT plays crucial roles in regulating key steps of atherosclerosis development, it may constitute a novel therapeutic target for the prevention and treatment of atherosclerosis. Here, we review the current literature regarding the roles of PVAT in the pathogenesis of atherosclerosis.
A series containing the highest nuclearity polyoxoniobate (PONb) nanoclusters, ranging from dimers to tetramers, has been obtained. They include one 114‐nuclear {Li8⊂Nb114O316}, one 81‐nuclear ...{Li3K⊂Nb81O225}, and one 52‐nuclear {H4Nb52O150}. The Nb nuclearity of these PONbs is remarkably larger than those of all known high‐nuclearity PONbs (≤32). Furthermore, the introduction of 3d Cu2+ ions can lead to the generation of extended inorganic–organic hybrid frameworks built from novel, high‐nuclearity, nanoscale heterometallic PONb building blocks {H3Cu3Nb78O222} or {H3Cu4(en)Nb78O222}. These building blocks also contain the largest number of Nb centers of any heterometallic PONbs reported to date. The synthesis of new‐type PONbs has long been a challenging subject in PONb chemistry.
Big, bigger, biggest: A series of record high‐nuclearity PONbs, ranging from 52‐nuclear {Nb52}, 81‐nuclear {Nb81} to 114‐nuclear {Nb114}, is made. The introduction of 3d Cu2+ ions allows the construction of extended inorganic–organic hybrid PONb frameworks based on giant heterometallic nanoclusters {Cu3Nb78} and {Cu4Nb78}.
The first series of niobium–tungsten–lanthanide (Nb‐W‐Ln) heterometallic polyoxometalates {Ln12W12O36(H2O)24(Nb6O19)12} (Ln=Y, La, Sm, Eu, Yb) have been obtained, which are comprised of giant ...cluster‐in‐cluster‐like ({Ln12W12}‐in‐{Nb72}) structures built from 12 hexaniobate {Nb6O19} clusters gathered together by a rare 24‐nuclearity sodalite‐type heterometal–oxide cage {Ln12W12O36(H2O)24}. The Nb‐W‐Ln clusters present the largest multi‐metal polyoxoniobates and a series of rare high‐nuclearity 4d‐5d‐4f multicomponent clusters. Furthermore, the giant Nb‐W‐Ln clusters may be isolated as discrete inorganic alkali salts and can be used as building blocks to form high‐dimensional inorganic–organic hybrid frameworks.
Giant heterometallic polyoxoniobates: A family of polyoxometalate‐based frameworks has been made by integrating s, 3d, 4d, 5d, and 4f metals. Multi‐component self‐assembly offers the first series of niobium–tungsten–lanthanide heterometallic polyoxometalates, which are the largest multi‐metal polyoxoniobates and contain rare nanosized hollow sodalite‐type tungsten–lanthanide–oxide cages.
Skin undergoes degenerative changes as it ages, which include the loss of elasticity, reductions in the epidermal thickness and collagen content, elastic fiber degeneration, and increased wrinkling ...and dryness. Skin aging can be significantly delayed by the administration of estrogen. Estrogen deficiency following menopause results in atrophic skin changes and the acceleration of skin aging. Estrogen administration has positive effects on human skin by delaying or preventing skin aging manifestations, but the use of estrogen replacement is a risk factor for breast and uterine cancer. Phytoestrogens are a large family of plant‐derived molecules possessing various degrees of estrogen‐like activity; they exhibit agonist or antagonist estrogenic properties depending on the tissue. These molecules could be ideal candidates to combat skin aging and other detrimental effects of hypoestrogenism. In this paper, we review the effects of phytoestrogens on human skin and the mechanisms by which phytoestrogens can alleviate the changes due to aging.
Recently fluoropolymers are of great interest as an oxidative binder and modifier in Al-based metastable intermixed composites (MICs) due to the high heat of reaction between Al-F and gas production ...characteristics. In this paper, Polytetrafluoroethylene (PTFE) and Polyvinylidene Fluoride (PVDF) have been incorporated into three typical Al-based MICs independently using CuO, Fe2O3, and Bi2O3 as oxidizers, where the contents of Al to metal oxide are maintained optimum stoichiometric ratios. Heats of reaction have been measured by a bomb calorimeter for mechanically mixed MICs samples, from which the optimum fluoropolymer content has been determined using the maximum calorific values as the criteria. After that, the optimized formulations have been prepared by a spray drying method. The thermal behavior, combustion characteristics and pressurization features of the studied Al-based MICs were evaluated and compared with those without fluoropolymers. The experimental results showed that with a minor inclusion of fluoropolymers, the combustion heat was improved by 3.8% to 8.6% depending on the type of oxidizers, and the onset temperature of the exothermic reaction was observed to be decreased by 250 °C for Al/CuO, 200 °C for Al/Fe2O3 and 16 °C for Al/Bi2O3 with a higher reaction heat release, showing a higher reactivity. Besides, the maximum pressure and pressurization rate were both increased for the fluorine-containing MICs, whereas the burn rates under confinement were found to drop significantly by 72% to 91%. The AlF3, Cu-Al alloy, and Fe-Al alloy are found in the condensed combustion products (CCPs), and it tends to have smaller and more uniform particles. It probably results from the large difference in the energy and mass transfer process on the combustion surface when the gaseous phase products are generated.
Primary porcine tracheal epithelial cells (PTECs) are an appropriate model for studying the molecular mechanism of various porcine respiratory diseases, including swine-origin mycoplasmas, which are ...isolated from respiratory tract of pigs and mainly found on the mucosal surface surrounding swine trachea. However, the short proliferation ability of primary PTECs greatly limits their lifespan. In this study, primary PTECs were carefully isolated and cultured, and immortal PTECs were constructed by transfecting primary PTECs with the recombinant constructed plasmid pEGFP-hTERT containing human telomerase reverse transcriptase (hTERT). Immortal PTECs (hTERT-PTECs) maintained both the morphological and functional characteristics of primary PTECs, as indicated by the expression of cytokeratin 18, cell-cycle analysis, proliferation assay, Western blotting, telomerase activity assay, karyotype analysis and quantitative RT-PCR. Compared to primary PTECs, hTERT-PTECs had an extended replicative lifespan, higher telomerase activity, and enhanced proliferative activity. In addition, this cell line resulted in a lack of transformed and grown tumors in nude mice, suggesting that it could be safely applied in further studies. Moreover, hTERT-PTECs were vulnerable to all swine-origin mycoplasmas through quantitative analysis as indicated by 50% color changing unit (CCU50) calculation, and no significant differences of adhesion ability between primary and immortal PTECs were observed. For the representative swine mycoplasma Mycoplasma hyopneumoniae (Mhp), except for DNA copies quantitative real-time PCR assay, indirect immunofluorescence assay and Western blotting analysis also depicted that hTERT-PTECs was able to adhere to different Mhp strains of different virulence. In summary, like primary PTECs, hTERT-PTECs could be widely used as an adhesion cell model for swine-origin mycoplasmas and in infection studies of various porcine respiratory pathogens.
ABSTRACT
Fast Radio Bursts (FRBs) are energetic phenomena that have significant implications for understanding fundamental physics and the Universe. Recent observations of FRB 121102, FRB 20220912A, ...and FRB 20201124A by the Five-hundred-meter Aperture Spherical Telescope showed high-burst rates and distinctive energy distribution and temporal properties. In this study, we examine these observations to investigate the scale invariance of the waiting times between bursts for intervals longer than approximately 1 s. Our analysis revealed a unified scaling law for these longer intervals, which is similar to the behaviour of solar flares. This discovery inspires us to suggest a dual analogy of the FRB scenario across the entire time intervals: with earthquake dynamics at subsecond scales and with solar flare dynamics beyond the one-second threshold. This threshold potentially aligns with the dynamic time-scale of neutron star crusts, offering insight of the occurrence of FRBs into the internal processes of neutron stars.
In the current study, a typical Sb mine was selected to explore the microbial community composition and assembly driven by the cocontamination of As/Sb with geographic distance. Our results showed ...that environmental parameters, especially pH, TOC, nitrate, total and bioavailable As/Sb contents largely affected the microbial community diversity and composition. The total and bioavailable As/Sb levels were significantly positively correlated with the relative abundance of Zavarzinella, Thermosporothrix and Holophaga, while the pH presented a significant negative correlation with the three genera, potentially implying they are important taxonomic groups in acid-mining soils. The cooccurrence network analysis indicated the environmental stress dominated by pH and As/Sb co-contamination affected the microbial modularity and interaction. Meanwhile, Homogeneous selection (HoS, 26.4–49.3%), and drift and others (DR, 27.1∼40.2%) were the most important assembly processes for soil bacterial, and the importance of HoS decreased and the DR increased with geographic distance to the contamination source respectively. Soil pH, nutrient availability, total and bioavailable As/Sb contents significantly affected the HoS and DR processes. This study provides theoretical support for microbial remediation in metal(loid)-contaminated soils.
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•As/Sb levels and biogeography both affect microbial diversity and composition.•As/Sb levels and biogeography mediate microbial interaction and cooccurrence pattern.•As/Sb levels and biogeography regulate microbial assembly processes and functions.
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