ABSTRACT
Composite explosives with fast reaction rate, high energy release efficiency, and remarkable combustion performance can be obtained by the interaction between homogeneous energetic materials and heterogeneous energetic materials and have broad application prospects. However, ordinary physical mixtures can easily cause separation between the components in the preparation process, which is not conducive to reflecting the advantages of composite materials. In this study, high-energy composite structured explosives with RDX modified by polydopamine as the core and PTFE/Al as the shell were prepared using a simple ultrasonic method. The study of morphology, thermal decomposition, heat release, and combustion performance demonstrated that the quasi-core/shell structured samples have higher exothermic energy, faster combustion rate, more stable combustion characteristics, and lower mechanical sensitivity than the physical mixture.
ABSTRACT
Solid propellants with high safety, excellent thermal decomposition, and green performance are hot and difficult research areas in aerospace. In this paper, AP@HNS (hexanitrostilbene) composites with core-shell structure were designed and prepared by an ultrasound-assisted method using polyurethane for the interfacial modification of ammonium perchlorate (AP). The results show that the AP@HNS composites have a complete and dense shell structure when the nano-HNS content of the shell layer is 15% or more, the synergistic decomposition effect between HNS and AP can advance the high-temperature decomposition peak of AP by 102.4 °C and increase the apparent heat release 2.55 times to 1388 J g-1, and HNS improves the energy of AP while reducing environmental pollution. The safety performance test shows that the nano-HNS with 15% mass content can increase the composite characteristic drop height H 50 to 32 cm and reduce the frictional susceptibility explosion probability to 77% (the H 50 of AP is 27 cm and the frictional susceptibility explosion probability is 95%). The insensitive shell layer HNS significantly improves the safety performance of AP through barrier and buffering effects. This technology is expected to provide new ideas for designing and preparing solid propellants with high energy, low susceptibility, and excellent thermal decomposition performance.
ABSTRACT
Aim: To investigate the enhancement of bioavailability by the usage of drug nanoparticles for increasing the efficacy of antidepressant therapeutic value. Materials & methods: Nano-amitriptyline HCI (AMT·HCl) particles were successfully prepared via a simple spray freeze drying (SFD) method. Results: The as-prepared nanoparticles are amorphous instead of crystalline. The mean size of AMT·HCl nanoparticles is 90 nm. In in vitro evaluation, AMT·HCl nanoparticles have greatly improved the dissolution compared with pure bulk materials, which have potential for enhancing human bioavailability and diminishing toxic effect. A nanoparticle formation mechanism was also proposed. Conclusion: These findings promote the development of antidepressant therapeutic evaluation based on the usage of AMT·HCl nanoparticles by SFD method and indicate that SFD is an alternative for a range of nanoparticle preparation in industrial pharmacy.
Subject(s)
Amitriptyline/chemistry , Nanoparticles/chemistry , Drug Compounding/methods , Freeze Drying/methods , Particle SizeABSTRACT
Highly energetic materials have received significant attention, particularly 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20). However, the application of this material was limited due to its high sensitivity. It is well known that the shape, size, and structure of energetic materials (EMs) significantly influence their sensitivity. At present, there are several ways to reduce the sensitivity of CL-20, such as spheroidization, ultrafine processing, and composite technology. However, only one or two of the abovementioned methods have been reported in the literature, and the obtained sensitivity effect was unsatisfactory. Thus, we tried to further reduce the sensitivity of CL-20 by combining the above three methods. The as-prepared composite was precipitated from the interface between two solutions of water and ethyl acetate, and the composite was insensitive compared with other reported CL-20-based EMs. The H50 value for the composite ranged up to 63 cm. This approach opens new prospects for greatly reducing the sensitivity of high Ems.
ABSTRACT
PURPOSE: To evaluate the efficacy of intermittent percutaneous needle sacral nerve stimulation (IPN-SNS) in women with idiopathic overactive bladder (IOAB) treated with tolterodine. MATERIALS AND METHODS: A total of 240 female patients diagnosed with IOAB were randomized to receive tolterodine only treatment (group 1, n = 120) or tolterodine combined with IPN-SNS (group 2, n = 120). Each group included 120 participants, who were divided into subgroups depending on whether they had dry OAB (urinary frequency and urgency) or wet OAB (urinary frequency and urgency with urgency incontinence). In the treatment group, patients received percutaneous IPN-SNS plus tolterodine (2 mg once daily), while in the control group, only tolterodine (2 mg once daily) was administered for 3 months. The voiding diary and urodynamic parameters were monitored, and patients' psychological depression and anxiety scores were recorded before and after treatment. RESULTS: There were significantly greater improvements in the conditions of first desire to void (FDV), maximum cystometric capacity (MCC), and daily average volumes, as well as the daily single maximum voided volumes in group 2 (P = .001) than in group 1. In addition, there were significantly greater decreases in self-rating depression scale (SDS) and self-rating anxiety scale (SAS) scores in group 2 compared with group 1 (P < .001). CONCLUSION: Combined treatment with tolterodine plus IPN-SNS can not only improve the symptoms of voiding dysfunction but can also reduce the concomitant depression and anxiety in women with IOAB, thereby improving patients' quality of life.
