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Dexmedetomidine (Dex), a highly selective α2-adrenergic receptor (α2AR) agonist, has an anti-inflammatory property and can alleviate pulmonary edema in lipopolysaccharide (LPS)-induced acute lung injury (ALI), but the mechanism is still unclear. In this study, we attempted to investigate the effect of Dex on alveolar epithelial sodium channel (ENaC) in the modulation of alveolar fluid clearance (AFC) and the underlying mechanism. Lipopolysaccharide (LPS) was used to induce acute lung injury (ALI) in rats and alveolar epithelial cell injury in A549 cells. In vivo, Dex markedly reduced pulmonary edema induced by LPS through promoting AFC, prevented LPS-induced downregulation of α-, β-, and γ-ENaC expression, attenuated inflammatory cell infiltration in lung tissue, reduced the concentrations of TNF-α, IL-1β, and IL-6, and increased concentrations of IL-10 in bronchoalveolar lavage fluid (BALF). In A549 cells stimulated with LPS, Dex attenuated LPS-mediated cell injury and the downregulation of α-, β-, and γ-ENaC expression. However, all of these effects were blocked by the PI3K inhibitor LY294002, suggesting that the protective role of Dex is PI3K-dependent. Additionally, Dex increased the expression of phosphorylated Akt and reduced the expression of Nedd4-2, while LY294002 reversed the effect of Dex in vivo and in vitro. Furthermore, insulin-like growth factor (IGF)-1, a PI3K agonists, promoted the expression of phosphorylated Akt and reduced the expression of Nedd4-2 in LPS-stimulated A549 cells, indicating that Dex worked through PI3K, and Akt and Nedd4-2 are downstream of PI3K. In conclusion, Dex alleviates pulmonary edema by suppressing inflammatory response in LPS-induced ALI, and the mechanism is partly related to the upregulation of ENaC expression via the PI3K/Akt/Nedd4-2 signaling pathway. [ABSTRACT FROM AUTHOR]

Previous researches investigated the adsorption properties and mechanism of clay minerals on antibiotic pharmaceuticals and personal care products (PPCPs) via batch adsorption experiments and X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) characterization, but many PPCPs exhibit different ionization states under different pH conditions; the research on the microscopic mechanism of different ionized PPCPs species adsorbed by clay minerals is very scarce. In this work, as a typical PPCPs contaminant, the common tetracycline (TC) was chosen as the study target; the adsorption micro mechanism of montmorillonite (MMT) on different TC species in aqueous solution was explored in details. Especially outstanding, for the first time, with the help of Multiwfn wavefunction program, quantitative analysis of molecular surface analysis and basin analysis were applied to quantitatively investigate the electrostatic interaction between MMT and different TC species, the possible positions of lone pair electrons. Independent gradient model (IGM) analysis and Hirshfeld surface analysis including local surface analysis were integrated to visualize the binding sites, interaction types, and relative strength between MMT and TC+/− or TC+/2− species, which can insight into the interaction essence from the microscopic perspective at the atomic level. [ABSTRACT FROM AUTHOR]

The novel nanocomposite Cu2O/MoS2-12 was synthesized by a simple two-step method. Cu2O nanospheres grow on the surface of MoS2 nanoflowers and have high photocatalytic activity. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) X-ray photoelectron spectroscopy (XPS), ultraviolet-visible light (UV-vis) photoluminescence (PL) spectroscopy, UV-vis diffuse reflection (UV-DRS), and electrochemical impedance (EIS) were used to study the structure and properties of the samples. The photocatalytic properties of the materials were evaluated by degrading methyl orange (MO) under visible light. The results show that CM-12 can completely degrade MO in 30 min, and the pseudo-first-order kinetic constant of degradation is 8.76 times that of pure Cu2O, which can be attributed to the composite material that can greatly reduce the recombination rate of photogenerated electrons and holes, and it has good stability. After repeated use for 5 times, the degradation rate can still reach 40%. Through experiments and theoretical results, a possible photocatalytic mechanism is proposed. To the best of our knowledge, this work was the first example of combining MoS2 with Cu2O and applying it to photocatalytic degradation of organic pollutants. It was beneficial for developing new photocatalysts and improving the catalytic performance of conventional photocatalysts. [ABSTRACT FROM AUTHOR]

Binary heterostructures Ag2ZrO3/TiO2 composites have been prepared by a facile calcination-hydrothermal, using ZrOCl2·8H2O, AgNO3, and TBOT as raw materials and PVP as a dispersant. X-ray diffraction (XRD), transmission electron microscope (TEM), Raman spectrometer, XPS, UV-vis DRS, and photoluminescence (PL) were employed to characterize the Ag2ZrO3/TiO2 composites. In an orthodox three-electrode system with RhB electrolyte solution, electrochemical measurements were carried out, and the results showed that it was a remarkable reversible reaction with reliable stabilization and favorable dynamics properties. The photocatalytic performances of Ag2ZrO3/TiO2 composites were estimated via the dilapidation of RhB under visible-light irradiation. In comparison to the pure TiO2, the photocatalytic presentation of Ag2ZrO3/TiO2 was enhanced. The presence of Ag2ZrO3 formed well-matched band level and constructed a heterogeneous interface to remarkably modify the bandgap energy with prolonged charge separation. The binary Ag2ZrO3/TiO2 composites can be regarded as a potential environmental material for applications in photocatalytic degradation of organic contaminants under visible-light irradiation. [ABSTRACT FROM AUTHOR]

A cetyltrimethylammonium bromide (CTAB) assisted bottom-up route to prepare Bi2WO6 fraction-let materials. WO3/Bi2WO6 binary hybrid with 2-D structure was designed by a facile hydrothermal process. Subsequently, RGO and g-C3N4 nanosheets were incorporated into WO3/Bi2WO6 via a cost-effective process. These nano-components of smart materials could simultaneously absorb and degrade contaminants in visible light. Nitroguanidine is an energetic material and harmful to the environment when released into the water. According to the data, NQ is more soluble in water than TNT or RDX, so NQ is more likely to cause water pollution. In this paper, the NQ in wastewater was degraded by using the RGO and g-C3N4 doped WO3/Bi2WO6. The results indicated that RGO-WO3/Bi2WO6(R-W-B) and g-C3N4-WO3/Bi2WO6 (G-W-B) showed greater degradation rate (0.02731 min− 1 and 0.02462 min− 1) as compare to WO3/Bi2WO6 (0.0084 min− 1). The improved photocatalytic performance of G-W-B or R-W-B accredited to the cascade structure of the synthesized materials. For G-W-B, the holes transferred from WO3 to Bi2WO6 and then to g-C3N4 which prolong the lifetime of photo-generated charges via the valence band potential gradient. The electrons transferred from Bi2WO6 to WO3 then to RGO for R-W-B. [ABSTRACT FROM AUTHOR]

A highly resourceful, eco-friendly, and recyclable magnetic adsorbent based on montmorillonite (CoFe2O4/MMT) was fabricated via a facile hydrothermal method to harvest tetracycline (TC) and ciprofloxacin (CIP) from pollutant water. The prepared adsorbent was characterized by XRD, FT-IR, SEM, and VSM methods to comprehend its structure, morphology, and magnetism. Effects of experimental parameters including solution pH, adsorption time, initial concentration, and ion strength were studied in details. The experimental adsorption data of TC and CIP fitted into pseudo-second-order kinetic model and Langmuir isotherm, respectively. The maximum adsorptions of TC and CIP could reach up to 240.91 and 224.00 mg/g. The thermodynamic study indicates that the adsorption process is spontaneous. In addition, the antibiotics can be further degraded under visible light environment and the magnetic sorbent can also be thermally regenerated.ᅟ [ABSTRACT FROM AUTHOR]

Density functional theory calculations using an SMD model were performed to investigate the effect of solvents (cyclohexanone, acetone, dimethyl formamide and dimethyl sulphoxide) on the crystal quality and sensitivity of RDX. The results indicate that the N-N bond length of the RDX molecule in solvents differs clearly from that in gas phase. The solvent effect on bond and dihedral angles of RDX molecule is small, however, the RDX molecule still maintains the AEE configuration. Natural population analysis shows that, due to solvation effects, RDX O atoms attract more electrons in solvents than in gas phase, while more positive charge distributes to the molecular skeleton. The calculations of N-NO bond BDE and nitro group charge as well as surface electrostatic potential parameters reveal that the solvent effect may be helpful to reduce the sensitivity of RDX, but this effect has an upper limit. Finally, it can be predicted qualitatively that the crystal quality of RDX crystallized from cyclohexanone and dimethyl sulphoxide will be higher than that from acetone and dimethyl formamide. Experimental results support these theoretical predictions. [ABSTRACT FROM AUTHOR]

The derivatives of 1,2,3,4-tetrazine may be promising candidates for high-energy density compounds and are receiving more and more attentions. In this study, a new derivative 6-amino-7-nitropyrazino[2,3-e][1,2,3,4]tetrazine 1,3,5-trioxide (ANPTTO) has been designed. The geometrical structure and IR spectrum in the gas phase were studied at the B3LYP/6-31G* level of density functional theory (DFT). The crystal structure was predicted by molecular mechanics method and refined by the GGA/BOP function of periodic DFT with the basis set of TNP. The gas phase enthalpy of formation was calculated by the homodesmotic reaction method. The enthalpy of sublimation and solid phase enthalpy of formation were also predicted. The detonation properties were estimated with the Kamlet-Jacobs equations based on the predicted density and enthalpy of formation in solid state. The available free space in the lattice and resonance energy were calculated to evaluate its stability. ANPTTO has a high stability and is a promising high energetic component with the density >2 g · cm, detonation velocity >9000 m · s, and detonation pressure >40 GPa. A synthetic route was proposed to provide a consideration for further study. [ABSTRACT FROM AUTHOR]

Molecular dynamics simulations have been performed to investigate the effect of acetone solvent on the crystal morphology of RDX. The results show that the growth morphology of RDX crystal in vacuum is dominated by the (111), (020), (200), (002), and (210) faces using the BFDH laws, and (111) face is morphologically the most important. The analysis of surface structures of RDX crystal indicates that (020) face is non-polar, while (210), (111), (002), and (200) faces are polar among which (210) face has the strongest polarity. The interaction between acetone solvent and each RDX crystal face is different, and the order of binding energy on these surfaces is (210) > (111) > (002) > (200) > (020). The analysis of interactions among RDX and acetone molecules reveal that the system nonbond interactions are primary strong van der Waals and electrostatic interactions containing π-hole interactions, the weak hydrogen bond interactions are also existent. The effect of acetone on the growth of RDX crystal can be evaluated by comparing the binding energies of RDX crystalline faces. It can be predicted that compared to that in vacuum, in the process of RDX crystallization from acetone, the morphological importance of (210) face is increased more and (111) face is not the most important among RDX polar surfaces, while the non-polar (020) face probably disappears. The experimentally obtained RDX morphology grown from acetone is in agreement with the theoretical prediction. [ABSTRACT FROM AUTHOR]

The interaction of seven pamidronate bisphosphonate (Pami-BPs) and its analogs with the hydroxyapatite (HAP) (100) surface was studied using density functional theory (DFT) and molecular dynamic (MD) methods. Partial Mulliken oxygen atomic charges in protonated structures were calculated at the level of B3LYP/6-31G*. The MD simulation was performed using the Discover module of Material Studio by compass force field. The results indicate the abilities of donating electrons of the oxygen atoms of the phosphate groups that are closely associated with the antiresorptive potency. The binding energies, including vdw and electrostatic, are used to discuss the mechanism of antiresorption. The results of calculations show that the strength of interaction of the HAP (100) face with the bisphosphonates is N > N > N > N > N > N > N according to their experimental pIC values. [ABSTRACT FROM AUTHOR]

[Figure not available: see fulltext.] The high energy density compound 3-azido-4-[(4-nitrofurazan-3-yl)- ONN-azoxy]furazan was synthesized from 3-amino-4-[(4-azidofurazan-3-yl)- NNO-azoxy]furazan by a catalytic oxidation process. The structure of the compound was characterized by IR, NMR spectroscopy and elemental analysis. The detonation performance of this compound was estimated by using density functional theory and the Monte Carlo method. The calculations predicted the density of the compound was 1.88 g·cm, the heat of detonation 1780.65 J·g, the detonation velocity 9150 m·s, and the detonation pressure 37.46 GPa. [ABSTRACT FROM AUTHOR]

To continue our previous work, the structure and some properties of a new series of 1,2,3,4-tetrazine 1,3-dioxides annulated with an imidazole ring or oxazole ring were studied in this paper. Four imidazolo-v-tetrazine 1,3-dioxides (ITDOs) I1-I4 and eight oxazolo-v-tetrazine 1,3-dioxides (OTDOs) O1-O8 were designed. We employed the density functional theory (DFT) in B3LYP/6-311++G(d,p) to study their geometrical structures and the homodesmotic reaction method to calculate the enthalpies of formation. Detonation properties and stabilities were also studied. Generally speaking, ITDOs and OTDOs have more preferable stabilities than TTDOs or pyrazolo-TDOs. I3, I4, O1, and O2 were found to be comparable to the energy level of RDX; O5 and O6 are even as powerful as HMX. The stabilities analysis in this paper can also prove that the five-membered ring deformation and the steric hindrance change caused by the different substituents will affect the stabilities of the structures of 1,2,3,4-tetrazine 1,3-dioxides annulated with a five-membered nitrogen-rich heterocycle. Other factors, such as the position of the electron-withdrawing substituents or the position of coordinated oxygen atom, are worthwhile to investigate in future work. [ABSTRACT FROM AUTHOR]