Regulation of external electric field on sensitivity of ICM energetic materials.

CONTEXT: [2,2'-Bi(1,3,4-oxadiazole)]-5,5'-dinitramide (ICM-101), 2,4,6-triamino-5-nitropyrimidine-1,3-dioxide (ICM-102), and 6-nitro-7-azido-pyrazol[3,4-d][1,2,3]triazine-2-oxide (ICM-103) are excellent China-made explosives, but their performance under external electric fields (EEF) has never been explored, especially sensitivity. To study the induction effect of EEF on it, the chemical reactivity, electron localization function (ELF), spectrum, and other parameters were calculated by density functional theory. The results show that the increasing EEF can weaken the △EHOMO-LUMO (△EHOMO-LUMO = EHOMO-ELUMO) materials, making the stability worse and the sensitivity higher. The proportion of the positive electrostatic surface potential area is also smaller under the increasing EEF, indicating that ICM molecules are becoming more and more unstable. The ELF and localized orbital locator (LOL) decrease with the increase of EEF strength, which suggests that the trigger bond length increases, the EBDE decreases, and the molecular sensitivity increases. When the intensity of EEF increases, the absorption peak of the molecular spectrum gradually redshifts, and even a weak new absorption peak appears, indicating that the color of the material may change. Finally, EEF strength affects electron density, nitro charge, and chemical reactivity parameters. METHODS: Gaussian 16 software was used for calculation. The calculation levels are B3LYP/6-311G+ (d, p) and B3LYP/Def2-TZVPP. The optimized structure has a local true minimum energy on the potential energy surface and no imaginary frequency. Multiwfn 3.8 and VMD 1.9.3 were used in this work to analyze the ICM series of energetic material wave functions. The strength range of EEF is 0.000-0.016 a.u., and the increasing gradient is 0.002 a.u.

Theoretical study on BTF-based cocrystals: effect of external electric field.

The external electric field plays an important role in the sensitivity of cocrystal energetic materials. To reveal the influence of external electric field on benzotrifuroxan/2,4,6-trinitroaniline (BTF/TNA), benzotrifuroxan/trinitroazetidine (BTF/TNAZ), benzotrifuroxan/1,3,5-trinitrobenzene (BTF/TNB), and benzotrifuroxan/trinitrotoluene (BTF/TNT) cocrystals' sensitivity, atoms in molecules (AIM), frontier molecular orbitals, nitro group charges (QNO2), electron density values (ρ), electrostatic surface potentials (ESPs), bond dissociation energy (EBDE), and interaction energy (Eint) of the C-NO2 bond were calculated by density functional theory at M062X-D3/ma-def2 TZVPP and B3LYP-D3/6-311 + G (d, p) levels in this article. The results indicate that both negative and positive electric fields reduce the energy gap of the BTF-based cocrystals, and BTF/TNAZ is the most sensitive cocrystal among the four cocrystals. For BTF/TNA and BTF/TNB, the EBDE and the negative charge of the nitro group decreases with increasing positive electric field strength, the Vs max increases with positive electric field strength, and the sensitivity of cocrystal eventually tends to increase under the positive electric field. For BTF/TNAZ and BTF/TNT, the EBDE and the negative charge of the nitro group decrease with increasing negative electric field strength, the Vs max increases with negative electric field strength, and the sensitivity of cocrystal eventually tends to increase under the negative electric field. Finally, the variation in bond length, nitro charge, and AIM electron density values are well correlated with the strengths of the external electric field.

Study on regulation effect of external electric field on energetic material 1-methyl-2,4,5-Trinitroimidazole.

In this work, in order to explore the regulation effect of external electric field (EEF) on various properties of 1-methyl-2,4,5-trinitroimidazole (MTNI), density functional theory (DFT) was used to investigate the molecular structure, electronic structure, frontier molecular orbital (FMO) and ultraviolet-visible (UV-Vis) spectroscopy of MTNI under EEF. The results show that: (1) EEF significantly affects the geometric and electronic structure of MTNI, which in turn affects the sensitivity of MTNI. (2) When the EEF in the positive direction increases, the energy gap of MTNI decreases significantly and the total density of states (TDOS) turns to be dominated by the nitro groups. (3) EEF makes MTNI appear new absorption peak in visible light region and thus makes the MTNI display color. The generation of new absorption peaks is also dominated by the nitro groups. We also carefully analyzed how EEF deforms structure of the MTNI from the perspective of atomic forces and decomposition of energy variation.

Structural transformation of methyl urotropine perchlorate under high pressure.

Based on the first-principles calculations of density functional theory (DFT), the crystal structure, molecular structure, electronic properties, and optical absorption properties of methyl urotropine perchlorate under hydrostatic compression in the range of 0 ~ 100 GPa were calculated. The results show that the crystal structure of methyl urotropine perchlorate undergoes two structural transformations under hydrostatic compression. The H1A-H1B bond breaks at 25 GPa, generating two new covalent bonds N3-H1A and O1-H1B. The covalent bonds of O2A-C1 and Cl1-H3A are formed at 85 GPa. The compression ratio of lattice constants (a, b, c) and unit cell volume change abruptly at 25 GPa and 85 GPa, respectively. The conclusion that new bonds are formed under high pressure is further demonstrated by analyzing the partial density of states (PDOS) of N3, H1A, O1, H1B, O2A, C1, Cl1, and H3A atoms. The absorption spectrum showed that the absorption peak of methyl urotropine perchlorate gradually enhanced with the increase of pressure and the highest absorption peak shifted to high frequency.

EGCG Alleviates Obesity-Induced Myocardial Fibrosis in Rats by Enhancing Expression of SCN5A.

Object: Obesity is an increase in body weight beyond the limitation of skeletal and physical requirement, as the result of an excessive accumulation of fat in the body. Obesity could increase the risk of myocardial fibrosis. (-)-Epigallocatechin-3-gallate (EGCG) is the most abundant substance in green tea and has been reported to have multiple pharmacological activities. However, there is not enough evidence to show that EGCG has a therapeutic effect on obesity-induced myocardial fibrosis. This study aims to investigate whether EGCG is a potential drug for obesity-induced myocardial fibrosis. Methods: Obesity-induced myocardial fibrosis rat model was established by HFD feeding for 36 weeks. EGCG was intragastrically administered at 160 mg/kg/d for the last 4 weeks. The pathological changes of myocardial fibrosis were evaluated by tissue pathological staining and collagen quantification. Furthermore, total RNA was extracted from the heart for RNA-seq to identify the changes in the transcript profile, and the relevant hub genes were verified by quantitative real-time PCR and western blot. Results: EGCG significantly relieved HFD diet-induced obesity and alleviated the pathology of myocardial fibrosis. Biochemical analysis showed that EGCG could relieve the burden of lipid metabolism and injury to the myocardium and transcript profile analysis showed that EGCG could alleviate obesity-induced myocardial fibrosis by increasing the level of Scn5a in the heart. Furthermore, quantitative real-time PCR and western blot analysis for SCN5A also confirmed this finding. Conclusion: Taken together, these results suggest that EGCG could protect against the obesity-induced myocardial fibrosis. EGCG plays an anti-myocardial fibrosis role by regulating the expression of SCN5A in the heart.

Theoretical studies of novel high energy density materials based on oxadiazoles.

In this study, 32 energetic compounds were designed using oxadiazoles (1,2,5-oxadiazole, 1,3,4-oxadiazole) as the parent by inserting different groups as well as changing the bridge between the parent. These compounds had high density and excellent detonation properties. The electrostatic potentials of the designed compounds were analyzed using density functional theory (DFT). The structure, heat of formation (HOF), density, detonation performances (detonation pressure P, detonation velocity D, detonation heat Q), and thermal stability of each compound were systematically studied based on molecular dynamics. The results showed that the -N3 group has the greatest improvement in HOF. For the detonation performances, the directly linked -N=N- and -NH-NH- were beneficial when used as a bridge between 1,2,5-oxadiazole and 1,3,4-oxadiazole, and it can also be found that bridge changing had little effect on the trend of detonation performance, while energetic groups changing influenced differently. In general, the introduction of nitro groups contributes to the improvement of the detonation performance of the compounds. In this study, the compounds containing the highest amount of nitro groups were found to have better detonation performance than their counterparts and were not significantly different from RDX and HMX.

[Effect of intermittent versus continuous exercise on obesity and fatty liver in rats fed with high-fat diet].

OBJECTIVE: To examine the effects of continuous and intermittent exercises on obesity and fatty liver in rats fed with high-fat diet. METHODS: Wistar rats were randomly assigned into routine diet (R) and high-fat diet (H) groups, and each group were subdivided into sedentary group (S), continuous exercise (CE) group, and intermittent exercise (IE) group (n=8). In the CE group, the rats were forced to swim continuously for 90 min once daily, and those in the IE group swam for 30 min for 3 times (at a 4-h interval) daily. Both the CE and IE groups exercised for 5 days a week for 8 consecutive weeks. After the experiment, the retroperitoneal, epididymal, and visceral white and brown adipose tissues, the liver, and the gastrocnemius muscle of the rats were weighed. The lipogenesis rate was determined by incorporation of (3)H(2)0 into saponified lipids, and the blood lipid profiles were analyzed. The body weight and food intake of the rats were recorded daily. RESULTS: IE appeared to be more efficient than CE in reducing the adverse effects of high-fat diet and sedentarism. Compared with CE, IE resulted in an improved lipid profile with reduced food intake, body weight gain, visceral and central adiposity, and fatty liver. The effect of high-fat diet and different exercises on weight gain, adiposity, fatty liver, and lipid profile in rats was associated to the manner of exercise, time of each session, age, gender, and length of observation period. CONCLUSION: Intermittent exercise is an important nonpharmacological strategy to control obesity and the related complications.