Silver(I)-Based Molecular Perovskite Energetic Compounds with Exceptional Thermal Stability and Energetic Performance.

In recent years, molecular perovskite energetic materials have attracted more attention because of their simple synthesis processes, high thermal stabilities, excellent performances, and great significance as a design platform for energetic materials. To explore the possibility of the application of molecular perovskite energetic materials in heat-resistant explosives, four silver(I)-based molecular perovskite energetic compounds, (H2A)[Ag(ClO4)3], where H2A = piperazine-1,4-diium (H2pz2+) for PAP-5, 1-methyl-piperazine-1,4-diium (H2mpz2+) for PAP-M5, homopiperazine-1,4-diium (H2hpz2+) for PAP-H5, and 1,4-diazabicyclo[2.2.2]octane-1,4-diium (H2dabco2+) for DAP-5, were synthesized by a one-pot self-assembly strategy and structurally characterized. The single-crystal structures indicated that PAP-5, PAP-M5, and DAP-5 possess cubic perovskite structures while PAP-H5 possesses a hexagonal perovskite structure. Differential thermal analyses showed that their onset decomposition temperatures are >308.3 °C. For PAP-5 and DAP-5, they have not only exceptional calculated detonation parameters (D values of 8.961 and 8.534 km s-1 and P values of 42.4 and 37.9 GPa, respectively) but also the proper mechanical sensitivity (impact sensitivities of ≤10 J for PAP-5 and 3 J for DAP-5 and friction sensitivities of ≤5N for both PAP-5 and DAP-5) and thus are of interest as potential heat-resistant primary explosive components.

Exosomal CagA derived from Helicobacter pylori-infected gastric epithelial cells induces macrophage foam cell formation and promotes atherosclerosis.

BACKGROUND: Seroepidemiological studies have highlighted a positive relation between CagA-positive Helicobacter pylori (H. pylori), atherosclerosis and related clinic events. However, this link has not been well validated. The present study was designed to explore the role of H. pylori PMSS1 (a CagA-positive strain that can translocate CagA into host cells) and exosomal CagA in the progression of atherosclerosis. METHODS: To evaluate whether H. pylori accelerates or even induces atherosclerosis, H. pylori-infected C57/BL6 mice and ApoE-/- mice were maintained under different dietary conditions. To identify the role of H. pylori-infected gastric epithelial cells-derived exosomes (Hp-GES-EVs) and exosomal CagA in atherosclerosis, ApoE-/- mice were given intravenous or intraperitoneal injections of saline, GES-EVs, Hp-GES-EVs, and recombinant CagA protein (rCagA). FINDINGS: CagA-positive H. pylori PMSS1 infection does not induce but promotes macrophage-derived foam cell formation and augments atherosclerotic plaque growth and instability in two animal models. Meanwhile, circulating Hp-GES-EVs are taken up in aortic plaque, and CagA is secreted in Hp-GES-EVs. Furthermore, the CagA-containing EVs and rCagA exacerbates macrophage-derived foam cell formation and lesion development in vitro and in vivo, recapitulating the pro-atherogenic effects of CagA-positive H. pylori. Mechanistically, CagA suppresses the transcription of cholesterol efflux transporters by downregulating the expression of transcriptional factors PPARγ and LXRα and thus enhances foam cell formation. INTERPRETATION: These results may provide new insights into the role of exosomal CagA in the pathogenesis of CagA-positive H. pylori infection-related atherosclerosis. It is suggested that preventing and eradicating CagA-positive H. pylori infection could reduce the incidence of atherosclerosis and related events.

MicroRNA-23a-5p promotes atherosclerotic plaque progression and vulnerability by repressing ATP-binding cassette transporter A1/G1 in macrophages.

Disruption of carotid vulnerable atherosclerotic plaque is responsible for acute ischemic stroke (AIS) and the early detection and intervention approach are greatly limited. Undertaking a microarray of microRNAs (miRNAs) in the plasma of AIS patients with carotid vulnerable plaques, miR-23a-5p was markedly elevated and was positively correlated with the plaque progression and vulnerability. Correspondingly, we found that miR-23a-5p expression was significantly increased in both plasma and macrophages from atherosclerosis mice. Bioinformatics analysis and in vitro knockdown experiments identified that ATP-binding cassette transporter A1/G1 as a novel target of miR-23a-5p. Luciferase reporter assays showed that miR-23a-5p repressed the 3' untranslated regions (UTR) activity of ABCA1/G1. Moreover, functional analyses demonstrated that transfection of miR-23a-5p inhibitor enhanced cholesterol efflux and decreased foam cell formation through upregulating ABCA1/G1 expression levels. Furthermore, long term in vivo systemically delivered miR-23a-5p antagomir significantly increased ABCA1/G1 expression in the aorta of ApoE-/- mice. Importantly, the miR-23a-5p antagomir therapy significantly reduced atherosclerosis progression and promoted plaque stability. Our observations indicate that miR-23a-5p promotes macrophage-derived foam cell formation and might be a key regulator contributing to atherosclerotic plaque progression and vulnerability.

Plastic Crystals with Polar Halochromate Anion: Thermosensitive Dielectrics Based upon Plastic Transition and Dipole Rotation.

Plastic crystals functioning with rotatable components offer new opportunities in areas such as modern optoelectronic materials. Here, by taking advantage of controllable rotation of the polar component within the ion-pair plastic-crystal system, we present two such crystals, namely, (Et4N)(CrO3X) (X = Cl or Br), which are unusual examples exhibiting two-staged thermosensitive dielectric responses above room temperature. The frequency-dependent response in the first stage is due to the structural phase transitions, whereas that in the second stage is induced by dynamic rotation of the polar halochromate anions in their NaCl-type plastic-crystal phases. The intrinsic mechanisms were also explicated by molecular dynamics simulations, providing a direct insight into the dynamic characteristics of these two compounds. These studies show that ionic plastic crystals functioning with polar groups are an attractive candidate as sensitive thermoresponsive dielectric materials.

Periodate-based molecular perovskites as promising energetic biocidal agents.

Epidemics caused by pathogens in recent years have created an urgent need for energetic biocidal agents with the capacity of detonation and releasing bactericides. Herein we present a new type of energetic biocidal agents based on a series of iodine-rich molecular perovskites, (H2dabco)M(IO4)3 (dabco = 1,4-diazabicyclo[2.2.2]octane, M = Na+/K+/Rb+/NH4 + for DAI-1/2/3/4) and (H2dabco)Na(H4IO6)3 (DAI-X1). These compounds possess a cubic perovskite structure, and notably have not only high iodine contents (49-54 wt%), but also high performance in detonation velocity (6.331-6.558 km s-1) and detonation pressure (30.69-30.88 GPa). In particular, DAI-4 has a very high iodine content of 54.0 wt% and simultaneously an exceptional detonation velocity up to 6.558 km s-1. As disclosed by laser scanning confocal microscopy observation and a standard micro-broth dilution method, the detonation products of DAI-4 exhibit a broad-spectrum bactericidal effect against bacteria (E. coli, S. aureus, and P. aeruginosa). The advantages of easy scale-up synthesis, low cost, high detonation performance, and high iodine contents enable these periodate-based molecular perovskites to be highly promising candidates for energetic biocidal agents. Electronic Supplementary Material: Supplementary material is available in the online version of this article at 10.1007/s40843-022-2257-6.

Facile synthesis and superior properties of a nitrogen-rich energetic Zn-MOF with a 2D azide-bridged bilayer structure.

Exploring the facile synthesis of Pb-free energetic metal-organic frameworks (EMOFs) with both high nitrogen content and high thermostability is a significant but challenging task in the field of MOF-based green energetic materials. Herein, a new EMOF, [Zn2(atz)3(N3)]n (atz = 5-amino-1H-tetrazole), has been synthesized by simply using a commercial ligand (atz) under mild conditions. A probable mechanism for the formation of azide groups in the product has been proposed, in which the fraction of C-N and N-N bonds in atz is the key. The X-ray single crystal structure analysis reveals the EMOF's unique graphene-like and azide-group-bridged 2D bilayer structure with gourd-type micropores. More impressively, the EMOF shows a high nitrogen content of 59.33% and superior thermostability of up to 362 °C, both among the best of existing EMOFs. In addition, detonation property calculations and sensitivity tests have been carried out, which demonstrate its high-energy and low-sensitivity features. Moreover, [Zn2(atz)3(N3)]n shows the ability to accelerate the thermal decomposition of ammonium perchlorate (AP) and hexanitrohexaazaisowurtzitane (CL-20), making it a potential combustion promoter for green and insensitive propellants.

High activity of NiCo2O4 promoted Pt on three-dimensional graphene-like carbon for glycerol electrooxidation in an alkaline medium.

Spinel oxide NiCo2O4 supported on a three-dimensional hierarchically porous graphene-like carbon (3D HPG) material has been firstly used to enhance the activity of Pt for glycerol electrooxidation. The addition of NiCo2O4 into the Pt/HPG catalyst can significantly improve the catalytic performance for glycerol oxidation. When NiCo2O4 is added to the Pt/HPG catalyst, the onset potential is 25 mV more negative than that on the Pt/HPG catalyst without NiCo2O4. The current density at -0.3 V on the Pt-NiCo2O4 (wt 10 : 1)/HPG electrode is 1.3 times higher than that on the Pt (30 wt%)/HPG electrode. The Pt-NiCo2O4 electrode presented in this work shows great potential as an electrocatalyst for glycerol electrooxidation in an alkaline medium.

Buzhongyiqi Decoction Protects Against Loperamide-Induced Constipation by Regulating the Arachidonic Acid Pathway in Rats.

Constipation is a common gastrointestinal disorder without effective treatment approach. Buzhongyiqi decoction (BZYQD) is a classical formula that has been commonly used for gastrointestinal disorders for nearly 1,000 years. In this study, we aimed to investigate the protective effect of BZYQD against loperamide-induced constipation and its potential mechanism. Rats with loperamide-induced constipation were orally administered BZYQD. BZYQD treatment obviously increased the small intestinal transit rate and alleviated colon tissue pathological damage. Subsequently, serum metabolomics study was performed to identify the metabolites affected by BZYQD. Metabolomics identified that the levels of 17 serum metabolites, including prostaglandin E2 (PGE2), arachidonic acid (AA), and inositol, were significantly changed in BZYQD-treated group compared with those in the loperamide-induced group. Pathway analysis revealed that those metabolites were mainly associated with arachidonic acid metabolism, biosynthesis of unsaturated fatty acids, ascorbate and aldarate metabolism, inositol phosphate metabolism. Additionally, BZYQD treatment down-regulated the cyclooxygenase-2 expression and decrease production of the proinflammatory mediator PGE2. Further study revealed that BZYQD administration decreased serum levels of the inflammatory factors IL-1ß and TNF-α, inhibited phosphorylation of the nuclear transcription factor NF-κB, and down-regulated expression of the inflammatory factors IL-1ß and IL-6 in the constipated rat colon. Moreover, BZYQD treatment also increased serum levels of inositol, motilin and gastrin, and promoted gastrointestinal motility. In conclusion, the present study suggested that BZYQD exerted a protective effect against loperamide-induced constipation, which may be associated with its role in regulation of multiple metabolic pathways.

LncRNA MIAT sponges miR-149-5p to inhibit efferocytosis in advanced atherosclerosis through CD47 upregulation.

Atherosclerotic cardio-cerebrovascular disease and death remain the leading cause of morbidity and mortality worldwide. Defective efferocytosis, the clearance of apoptotic cells by macrophages, is thought to lead to increased inflammation and necrotic core formation in atherosclerotic lesions. However, very little is known about the role of long noncoding RNA (lncRNA) during this process. Here we show that lncRNA myocardial infarction associated transcript (MIAT) was markedly elevated in the serum of patients with symptoms of vulnerable atherosclerotic plaque and the macrophages of necrotic cores in an advanced atherosclerosis mouse model. MIAT knockdown attenuated atherosclerosis progression, reduced necrotic core size, and increased plaque stability in vivo. Furthermore, MIAT knockdown promoted clearance of apoptotic cells by macrophages in vivo and in vitro. Mechanistic studies revealed that MIAT acted as a micro RNA (miRNA) sponge to positively modulate the expression of anti-phagocytic molecule CD47 through sponging miR-149-5p. Together, these findings identified a macrophage MIAT/miR-149-5p /CD47 pathway as a key factor in the development of necrotic atherosclerotic plaques.

The cation-dependent structural phase transition and dielectric response in a family of cyano-bridged perovskite-like coordination polymers.

A family of cyano-bridged perovskite-like coordination polymers (CPs), [(CH3)nNH(4-n)]2[KFe(CN)6] (n = 1 (1), 2 (2), 3 (3), and 4 (4)), were synthesized and characterized. The differential scanning calorimetry measurements and variable-temperature single-crystal X-ray structural analyses revealed that, owing to the deformation of the host framework as well as the dynamic transition of the guest cation between the static/ordered and dynamic/disordered states, the four CPs undergo structural phase transitions (at 429, 226, 316, and 350 K, respectively) with the symmetry breakings dependent on the symmetries of the encapsulated guest cations. The modulated differential scanning calorimetry measurement suggested that the phase transitions of 1 and 3 have more striking kinetic processes related to their drastic deformation of the host framework as well as a very significant alteration of the host-guest interaction during the phase transition. Moreover, accompanying the transitions between low- and high-temperature phases, the step-like transitions between low and high dielectric states were observed in 1-3, and the corresponding change in amplitude of the dielectric constant is dependent on the total dipole moment of each cage in the high-temperature phase. The investigation on these host-guest CPs deepens the understanding of the relationship between the dipole moment of guest cations and the dielectric behaviour of materials, shedding light on the search for new switchable molecular dielectrics.

Molecular Dynamics of Flexible Polar Cations in a Variable Confined Space: Toward Exceptional Two-Step Nonlinear Optical Switches.

The changeable molecular dynamics of flexible polar cations in the variable confined space between inorganic chains brings about a new type of two-step nonlinear optical (NLO) switch with genuine "off-on-off" second harmonic generation (SHG) conversion between one NLO-active state and two NLO-inactive states.

Insight into the molecular dynamics of guest cations confined in deformable azido coordination frameworks.

The molecular dynamics of encapsulated cations within perovskite-like coordination polymers [(CH3)3NH][M(N3)3] (M = Mn, Cd) are investigated, which are well controlled by the confined space of a deformable azido framework. The Mn-based compound provides a rare example that features an unvaried/varied rotational energy barrier during its two different structural phase transitions.

[Effects of cinnamic acid and vanillin on grafted eggplant root growth and physiological characteristics].

Choosing Solanum torvum as rootstock and cultivated Xi'anlü eggplant as scion, a pot culture experiment was conducted to study the effects of autotoxic substances (cinnamic acid and vanillin) on the root growth, antioxidase activity, and osmoregulation substances content of grafted eggplant, own-rooted eggplant, and rootstock eggplant. Cinnamic acid and vanillin had allelopathic effects on the root system of test eggplants, with low concentration promoting and higher concentration inhibiting the root growth and physiological metabolism. For own-rooted eggplant, the critical concentration of cinnamic acid and vanillin for promotion or inhibition was 0.1 mmol x kg(-1) and 0.5 mmol x kg(-1), respectively; whereas for grafted and rootstock eggplants, it was 0.5 mmol x kg(-1) and 1 mmol x kg(-1), respectively. The root resistance to autotoxic substances was in the order of root-stock eggplant > grafted eggplant > own-rooted eggplant. Higher concentration cinamic acid (0.5-4 mmol x kg(-1)) and vanillin (1-4 mmol x kg(-1)) enhanced the SOD enzyme activity and the proline and soluble sugar contents of grafted eggplant root by 8.50%-24.50%; 9.39%-27.64%, and 12.77%-81.81%, respectively, compared with own-rooted eggplant. The soluble protein content, fresh mass, dry mass, and root activity of grafted eggplant roots were significantly higher than those of own-rooted eggplant, suggesting that grafted eggplant had a strong resistance of rootstocks to autotoxic substances, which alleviated the negative effect of autotoxic substances on root growth.

[Regulation effects of grafting on cinnamic acid and vanillin in eggplant root exudates].

Cinnamic acid and vanillin are the allelochemicals commonly existed in eggplant root exudates. With pot culture experiment, the regulation effects of grafting on the cinnamic acid and vanillin in eggplant root exudates were studied, and the results showed that grafting decreased the amount of the two substances, especially of vanillin, in eggplants root system. The maximum reduction amount of cinnamic acid reached 68.96%, and that of vanillin reached 100%. Under the stress of exotic cinnamic acid and vanillin, especially of exotic cinnamic acid, grafting relieved the autotoxicity of the two substances on eggplants. Compared with own-rooted eggplant, grafted eggplant had a higher plant height and a larger stem diameter, its leaf chlorophyll content increased by 5.26%-13.12%, root electric conductivity and MDA content decreased, and root SOD activity enhanced.