Search

The limited application of garlic essential oil (GEO) is attributed to its pungent taste, poor water solubility and low bioavailability. Liposomes are nontoxic, biodegradable and biocompatible, and β-cyclodextrin can inhibit undesirable odors and improve the stability and bioavailability. Thus a promising dual-layer GEO β-cyclodextrin inclusion compound liposome (GEO-DCL) delivery system with both advantages was designed and prepared in this study. Experimental results indicated that the encapsulation efficiency of GEO-DCLs was 5% higher than that of GEO liposomes (GEO-CLs), reaching more than 88%. In vitro release experiment showed that the release rate of GEO in GEO-DCLs was 40% lower than that of GEO-CLs after incubation in gastric juice for 6-h, indicating that the stability of GEO-DCLs was better than GEO-CLs. Evaluation of the effects of GEO-DCLs on lowering blood lipid levels in hypercholesterolemia mice. GEO-DCLs could reduce the weight and fat deposition in hypercholesterolemia mice. Inhibiting the increase of TC, LDL-C, and decrease of HDL-C in mice. The degree of liver injury was decreased, the number of round lipid droplets in liver cytoplasm was reduced, and the growth of fat cells was inhibited. The lipid-lowering effects of GEO-DCLs were dose-dependent. GEO-DCL can improve the bioavailability of GEO and improve dyslipidemia. Based on GEO's efficacy in lowering blood lipids, this study developed a kind of GEO-DCL compound pomegranate juice beverage with good taste, miscibility and double effect of reducing blood lipids. This study lays a foundation for the application of GEO in the field of functional food. [Display omitted] • Cyclodextrin liposome encapsulation way was first use in garlic essential oil (GEO). • GEO β-cyclodextrin inclusion liposomes (GEO-DCLs) can release GEO slowly. • GEO-DCLs has better simulated gastric fluid stability. • GEO-DCLs could intervene dyslipidemia caused by high fat diet. • A compound GEO-DCLs beverage with double effect of lowering blood lipid was prepared. [ABSTRACT FROM AUTHOR]

Benzylpentazole ( B) and its derivatives ( B-NH ~ B-NF ) with electron-donating group (−NH, −NHMe, −NMe, and−OH) and electron-withdrawing group (−NO, −CN, −CF and −NF) were studied using density functional theory to assess their potentials for replacing phenylpentazole ( PhN ) as cyclo-N precursor. The pyrolysis mechanisms of the N ring and the C─N bond connecting pentazole and benzyl, bond lengths, and atomic charge have been investigated for revealing the effects of substituents on stability and assessing the possibilities of benzylpentazoles as cyclo-N precursor. Substituents especially electron-withdrawing groups lower the N ring stability and the C─N bond stability of B simultaneously. Compared to PhN , benzylpentazoles mostly possess higher activation energy for the N ring decomposition (81.2 ~ 101.7 kJ/mol), lower C─N bond dissociation energy (385.6 ~ 452.8 kJ/mol), and higher chemical stability (7.83 ~ 8.49 eV). B and B- NMe with the highest N ring stability, appropriate C─N bond stability, and chemical stability are the most potential candidates for replacing PhN as cyclo-N precursor. [ABSTRACT FROM AUTHOR]

High energetic materials tetranitroacetimidic acid (TNAA) and tetranitroacetamide (NTNAA) with positive oxygen balance (OB = 30%) are highly potential replacements for ammonium perchlorate (AP). Tautomerization from TNAA to NTNAA is feasible, reflected by the activation energy of 160.2∼170.0 kJ/mol. No transition state appears on the C-NO2 bond breaking, which triggers pyrolysis of two compounds. The C-NO2 bond dissociation energies are 116.1∼167.2 kJ/mol and 120.4∼174.6 kJ/mol for TNAA and NTNAA, respectively. The chemical stabilities of TNAA and NTNAA are higher than that of the insensitive explosive 1,1-diamino-2,2-dinitroethylene. TNAA and NTNAA possess lower impact sensitivities ( h50 ≥ 77.51 cm) than AP does. Detonation properties of the composite explosives containing TNAA or NTNAA are comparable with that of the composite explosives containing AP. The acceptable stabilities, highly positive OB, environmentally friendly decomposition products, and the comparable ability to improve detonation performance of composite explosives show that TNAA and NTNAA are potential replacements for AP as an oxidizer used in composite explosives. [ABSTRACT FROM AUTHOR]

Structures of the salts I-IV formed by 3,6-dihydrazido-1,2,4,5-tetrazine with HNO3, HN(NO2)2, HClO4, and HC(NO2)3, respectively, were studied using dispersion-corrected density functional theory. The intramolecular hydrogen bond energies of I-IV were estimated using the quantum theory of atoms in molecules. The total hydrogen bond energies ( EH,tot) have the order of I (65.60 kcal/mol) > II (46.24 kcal/mol) > III (39.13 kcal/mol) > IV (19.68 kcal/mol). In addition, the charge transfer ( q), binding energy ( Eb), lattice energy ( HL), dispersion energy ( Edis), and second-order perturbation energy ( E2) were evaluated for studying the intramolecular interactions between the cation and anion. Linear relationships exist between any two of EH,tot, qtot, Eb, and E2,tot. HLs have the same variation trend as h50s (characteristic height) and may be used as the indicator of impact sensitivity. The HOMOs and LUMOs of I-IV are derived from the HOMOs of the isolated anions and the LUMOs of the isolated cations, respectively. Ultraviolet spectra of I-IV have the strongest absorptions at around 442, 445, 427, and 587 nm, respectively. The excitations HOMO→LUMO to HOMO-7→LUMO play important roles in the first three excited states. [ABSTRACT FROM AUTHOR]

Three high nitrogen compounds, 1,2-di(5H-pyrazolo[1,5-d]tetrazol-5-yl)diazene (DPyTD), 1,2-di(6H-[1–3]triazolo[1,5-e]tetrazol-6-yl)diazene (DTrTD) and 1,2-di(3H-tetrazolo[1,5-e]tetrazol-3-yl)diazene (DTeTD) with N 12 , N 14 or N 16 chain produced by the internal 1,3-dipolar cycloadditions of bis(azidoazolyl)diazenes (1,2-bis(3-azido-1H-pyrazol-1-yl)diazene, 1,2-bis(4-azido-1H-1,2,3-triazol-1-yl)diazene and 1,2-bis(5-azido-1H-tetrazol-1-yl)diazene), were studied using the density functional theory (DFT). The energies ( E a,1 and E a,2 ) required for the two internal cycloadditions of bis(azidoazolyl)diazenes were predicted at the B3LYP/6-311++G∗∗ (128.8–138.5 and 130.2–144.7 kJ/mol), B3PW91/6-311++G∗∗ (124.9–133.0 and 125.5–138.1 kJ/mol) and B3LYP/Aug-cc-pvdz (119.0–128.0 and 120.5–133.0 kJ/mol) levels of DFT. The bend of the azido group starts the 1,3-dipolar cycloadditions. Two 1,3-dipolar cycloadditions are independent. The IR, UV, and NMR spectra were simulated for characterization. The frontier orbitals cover the whole structure leading to small energy gaps (2.99–4.02 eV). The predicted impact sensitivities (17.3–22.1 J) show the acceptable stability of title compounds. [ABSTRACT FROM AUTHOR]

The salts formed by N and metallic cations (Na, Fe and Ni) may be potential candidates for superior energetic materials and were studied with the density functional theory B3LYP method and ab initio molecular orbital theory MP2 method using the 6-31G* and LanL2DZ basis sets. Thermal dissociations of these salts are initiated by breaking of the N ring, and those of Fe(N) and Ni(N) proceed sequentially through two transition states. In gas phase, the activation barriers ( Es, in kJ/mol) of thermal dissociations decrease in the order of N > NaN > HN > Ni(N) > Fe(N). Products of initial pyrolysis of these salts are N and metallic azide. The frontier orbital energy gaps (in eV) are N (8.27) > HN (7.40) > NaN (5.10) > Fe(N) (4.92) > Ni(N) (3.43). The more stable salt has the smaller electron transfer between the cation and anion. [ABSTRACT FROM AUTHOR]

Three stable conformations of salts formed from 3,6-diguanidino-1,2,4,5-tetrazine-1,4-di-N-oxide (DTDO) and HNO and HN(NO) were studied using the density functional theory. For two salts, free energies ( Gs) and total energies ( Es) of the three conformations increase in the same order. Intramolecular interactions in the three conformations, such as the hydrogen bonding interaction ( E), the charge transfer ( q), the binding energy ( E), the dispersion energy ( E) and the second-order perturbation energy ( E), decrease in completely opposite order to that of Gs and Es. Different conformations have distinct effects on the chemical stabilities and UV stabilities of two salts. Aromaticities of tetrazine in different conformations are slightly different. Although stabilities of the three conformations are different, their values are comparable. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

We investigate a 3-dimensional system of the predator–prey dynamics with disease for the prey. This system is a reaction–diffusion model with ratio-dependent Michaelis–Menten functional response and diffusion in a bounded domain. By applying the comparison principle, Liapunov function and linearized method, we are able to achieve the sufficient conditions of the permanence, the global stability of the boundary equilibria and the positive equilibrium, and the local stability of the positive equilibrium. Numerical simulations are also given to illustrate the applications. [ABSTRACT FROM AUTHOR]

Nitrogen-rich 1,2,4-triazole ( 1) and 1,2,3-triazole ( 2) react as bases with the oxygen-rich acids HNO3 ( a), HN(NO2)2 ( b), and HClO4 ( c) to produce energetic salts ( 1a, 1b, and 1c and 2a, 2b, and 2c, respectively) potentially applicable to composite explosives and propellants. In this study, these salts were studied with the dispersion-corrected density functional theory. For the isomers such as 1a and 2a, the more negative Δr Gm of the formation reaction leads to a higher thermally stable salt. The ability to form intramolecular hydrogen bonds predicted with the quantum theory of atoms in molecules has the order of 2 > 1. Different hydrogen bonds result in different second-order perturbation energies, redshifts in IR, and electron density differences. The charge transfer, binding energy, dispersion energy, lattice energy, and energy gap between frontier orbits in the salts of 1 are larger than those of 2, which is helpful for stabilizing the former, and 1 is more obviously stabilized than 2 by formation of salts. Different conformations of 1 and 2 hardly affect the frontier orbital distributions. Base 1 is a more preferred base than 2 to form salts. [ABSTRACT FROM AUTHOR]

In recent years, there has been a considerable interest in developing high oxygen compounds as oxidizers for, for example, composite explosives. 2,2,3,3-Tetranitroaziridine (TNAD) is a new designed compound with high oxygen balance (25.11%) and is environmentally friendly. A synthesis route of TNAD was suggested in this study, and the thermodynamic possibilities of reactions were evaluated by the changes in the free energy obtained with the density functional theory (DFT). The strong strain energy ( Es = 292.28 kJ/mol) of TNAD leads the C-C bond in the ring more fragile than the C-NO2 bond, and the activation energy ( Ea) of of the C-C bond (119.14 kJ/mol at the B3LYP/6-31G* level of DFT) is higher than that of 2,4,6-trinitrotoluene (TNT) (113.00 kJ/mol). The topological analysis with the contour maps of electron density was used to show the changes of the electron density at the critical points (BCP) in the process of of the C-C bond. In addition, the energy gap between the frontier orbitals of TNAD (Δ Eg = 5.22 eV) is slightly higher than that of 1,3,3-trinitroazetidine (TNAZ, 5.06 eV). And the HOMO → LUMO transition plays important roles in the UV spectrum. The noncovalent interactions in the TNAD/RDX composite were estimated to be stronger than that in TNAZ/RDX, that is, the former may have better compatibility than the latter. TNAD/RDX with the weight ratio of wTNAD/ wRDX = 0.46/0.54 has the wonderful performance ( D = 9.14 km/s, P = 37.30 GPa, and Is = 285.47 s) which is better than that ( D = 8.85 km/s, P = 35.09 GPa, and Is = 272.33 s) of TNAZ/RDX with the same weight ratio. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]