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Xin Li,1 Xiaoqian Jia,2 Hu Niu2 1Department of Breast and Thyroid Surgery, Heze Municipal Hospital, Heze, Shandong, China; 2Department of General Surgery 2, The Fourth People’s Hospital of Jinan, Jinan, Shandong, China Background: Multidrug resistance is responsible for the poor outcome in breast cancer therapy. Lapa is a novel therapeutic agent that generates ROS through the catalysis of the NAD(P)H:quinone oxidoreductase-1 (NQO1) enzyme which significantly facilitate the intracellular accumulation of the co-delivered DOX to overcome MDR in cancer cells. Purpose: Herein, in our study, nanostructured lipid carrier (NLC) co-delivering β-lapachone (Lapa) and doxorubicin (DOX) was developed (LDNLC) with the aim to overcome the multidrug resistance (MDR) in breast cancer therapy. Patients and methods: Lapa and DOX were loaded into NLC to prepare LDNLC using melted ultrasonic dispersion method. Results: The well designed LDNLC was nanoscaled particles that exhibited preferable stability in physiological environment. In vitro cell experiments on MCF-7 ADR cells showed increased DOX retention as compared to DOX mono-delivery NLC (DNLC). In vivo anti-cancer assays on MCF-7 ADR tumor bearing mice model also revealed significantly enhanced efficacy of LDNLC than mono-delivery NLCs (DNLC and LNLC). Conclusion: LDNLC might be a promising platform for effective breast cancer therapy. Keywords: β-lapachone, doxorubicin, nanostructured lipid carriers, multidrug resistance, breast cancer

Several polymer binders based on 3,3-bis(azidomethyl)oxetane (BAMO) were studied to explore the compatibility and interaction of the energetic binders with three common energetic oxidants. The compatibilities were studied by differential scanning calorimetry (DSC) and the rating was obtained according to the evaluated standards. The results showed that all the binders based on BAMO had a good compatibility with cyclotrimethylenetrinitramine (RDX), cyclotetramethylenetetranitroamine (HMX), and hexanitrohexazaiso- wurtzitane (CL-20). The work of adhesion (Wa) between binders and explosives was tested via measurement of contact angle and the results present the same orders: chain-extended PBAMO by isophorone diisocyanate with diethyl bis(hydroxymethyl) malonate (IPDI-DBM-CE) > chain- extended PBAMO by isophorone diisocyanate (IPDI-CE) > poly(3,3-bis(azidomethyl)oxetane) (PBAMO). In addition, similar results were found in the binding energies reported by the molecular dynamics (MD), and the average values of Ebinding for IPDI-DBM-CE systems were larger than others due to the formation of hydrogen bonds between –COOEt and –NO2, which would improve the bonding abilities.

TKX-50-based PBX (PBX-T) is prepared by solution–water suspension method using dihydroxylammonium 5,5′-bistetrazole-1,1′-diolate (TKX-50) as the explosive. The thermal behavior of PBX-T is investigated under a nonisothermal condition by using TG-DTG and DSC method. The kinetic parameters (E a = 167.98 kJ mol−1 and A = 1016.05 s−1) for the main thermal decomposition reaction of PBX-T are calculated from the analysis of DSC curves by differential method and integral method, and the nonisothermal kinetic equation of the exothermic process is $${\text{d}}\alpha /{\text{d}}T = \left( {10^{16.05} /2\beta } \right)5\left( {1 - \alpha } \right)\left[ { - \ln \left( {1 - \alpha } \right)} \right]^{3/5} \exp ( - 2.0204 \times 10^{4} /T)$$ , suggesting that the main exothermic decomposition reaction mechanism of PBX-T is classified as Avrami–Erofeev equation. The specific heat capacity (C p) of PBX-T is measured using continuous C p mode of C80 micro-calorimeter. Depending on the thermal decomposition parameters and Chinese Military Standards GJB 772A-97 method, the adiabatic time, self-accelerating decomposition temperature, sensitivities, and 5-second flash point on of PBX-T are obtained.

The enthalpies of dissolution for dihydroxylammonium 5, 5′-bistetrazole-1,1′-diolate (TKX-50) in water were measured using a C-80 Calvet microcalorimeter at four different temperatures under atmospheric pressure. Differential enthalpies (Δdif H) and molar enthalpies (Δdiss H) of dissolution were calculated. The corresponding kinetic equations that describe the dissolution rate at the four experimental temperatures are dα/dt = 10−3.06(1 − α)0.59 (T = 298.15 K), dα/dt = 10−2.98(1 − α)0.37 (T = 303.15 K), dα/dt = 10−2.90(1 − α)0.37 (T = 308.15 K), dα/dt = 10−2.85(1 − α)0.43 (T = 313.15 K). In addition, the determined values of the activation energy E and pre-exponential factor A for the dissolution process are 25.08 kJ mol−1 and 21.98 s−1, respectively.

Electric coalescence is an effective way to achieve high performance of separating small dispersed water droplets from oils. We investigated the coalescence and break-up behaviors of double conducting droplets dissolved 0.4394 M NaCl in the presence of electric field using molecular dynamic simulations. Our results provide that the critical electric field (Ec) and the corresponding conical angle for coalescence are 0.52 V/nm and 42°. Two conducting droplets are driven to approach, contact, and eventually coalescence by the electric field when the applied electric field is weaker than Ec. Nevertheless, in the presence of the electric field stronger than Ec, the partial break-up that small daughter droplets break away from their mother droplet occurs due to the exchange and neutralization of positive and negative charged ions in the connecting liquid bridge. As the electric field increases further to 0.80 V/nm or stay above, the strong electric field leads to the entire break-up process, accompanied with ion jetting before droplets contacting.

Dihydroxylammonium 5,5′- bistetrazole-1,1′-diolate (TKX-50) was used to prepare TKX-50-based polymer bonded explosive (PBX) for the first time in this study. The thermal stabilities and the kinetic parameters of TKX-50 and TKX-50-based PBX were compared via Differential Scanning Calorimetry (DSC), Thermal Gravity-Differential Thermal Gravity (TG-DTG) and Accelerating Rate Calorimeter (ARC). Furthermore, in order to know about their thermal safeties comprehensively, an advanced thermal analysis program based on Friedman method was employed to calculate the thermal safety parameters for TKX-50 and its PBX. With its help, two important safety parameters (time to maximum rate under adiabatic conditions (TMRad) and self-accelerating decomposition temperature (SADT)) for the two energetic materials were calculated and discussed. Finally, based on the safety parameters, effects of storage conditions and ambient temperatures on the thermal explosions of TKX-50 and TKX-50-based PBX were further studied by using finite element analysis (FEA).