子母弹燃气抛放装置内弹道气动模型

本文介绍了燃气抛放装置的结构原理,根据气体动力学原理提出了该装置的物理数学模型,通过计算机仿真,得到的P—t曲线和子弹抛出速度。与实验比较,理论结果和实验结果基本相符。     

TSP系统全充满旋转减速伞运动特性的研究

末敏弹是新一代反坦克武器。该文对末敏弹系统全充满旋转减速伞的运动特性进行研究，首行从流体动能的概念引入降落伞的附加质量和附加惯性矩，从完整系统的广义欧拉运动方程建立降落伞的运动模型；然后与末敏弹系统完整的运动方程组联立求解。     

Drug carrying hydrogel base wound dressing

A special drug carrying hydrogel base wound dressing by radiation preparation is developed for hospital uses. The dressing possesses high water absorption property. Radiation preparation is carried out using a Van de Graaff Accelerator as an electron radiation source. The effect of absorbed dose and cmount of crosslinking agent on the gel fraction and swelling ratio of the hydrogel were determined respectively. As a bio-medical material, standard tests were made. Results showed properties conforming with requirements for clinical applications. Results obtained from clinical tests were good.     

一种整装式液体发射药燃烧控制技术

介绍了整装式条件下液体发射药（ＢＬＰ）的一种燃烧控制技术。采用多孔介质及其附着剂，改善并控制填充于其中的液体发射药燃烧性能。在不采用喷射雾化装置条件下，实现液体发射药稳定燃烧，控制燃烧速度，强化化学反应过程。     

Designing New Antibacterial Wound Dressings: Development of a Dual Layer Cotton Material Coated with Poly(Vinyl Alcohol)_Chitosan Nanofibers Incorporating Agrimonia eupatoria L. Extract

Wounds display particular vulnerability to microbial invasion and infections by pathogenic bacteria. Therefore, to reduce the risk of wound infections, researchers have expended considerable energy on developing advanced therapeutic dressings, such as electrospun membranes containing antimicrobial agents. Among the most used antimicrobial agents, medicinal plant extracts demonstrate considerable potential for clinical use, due primarily to their efficacy allied to relatively low incidence of adverse side-effects. In this context, the present work aimed to develop a unique dual-layer composite material with enhanced antibacterial activity derived from a coating layer of Poly(vinyl alcohol) (PVA) and Chitosan (CS) containing Agrimonia eupatoria L. (AG). This novel material has properties that facilitate it being electrospun above a conventional cotton gauze bandage pre-treated with 2,2,6,6-tetramethylpiperidinyl-1-oxy free radical (TEMPO). The produced dual-layer composite material demonstrated features attractive in production of wound dressings, specifically, wettability, porosity, and swelling capacity. Moreover, antibacterial assays showed that AG-incorporated into PVA_CS’s coating layer could effectively inhibit Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) growth. Equally important, the cytotoxic profile of the dual-layer material in normal human dermal fibroblast (NHDF) cells demonstrated biocompatibility. In summary, these data provide initial confidence that the TEMPO-oxidized cotton/PVA_CS dressing material containing AG extract demonstrates adequate mechanical attributes for use as a wound dressing and represents a promising approach to prevention of bacterial wound contamination.     

Pullulan hydrogels improve mesenchymal stem cell delivery into high-oxidative-stress wounds

Cell-based therapies for wound repair are limited by inefficient delivery systems that fail to protect cells from the acute inflammatory environment. Here, a biomimetic hydrogel system is described that is based on the polymer pullulan, a carbohydrate glucan known to exhibit potent antioxidant capabilities. It is shown that pullulan hydrogels are an effective cell delivery system and improve mesenchymal stem cell survival and engraftment in high-oxidative-stress environments. The results suggest that glucan hydrogel systems may prove beneficial for progenitor-cell-based approaches to skin regeneration.     

Cytokine loaded biopolymers as a novel strategy to study stem cells during wound-healing processes

The biopolymer matrigel loaded with cytokine can be used for the recruitment in vivo of specific cell populations and as a vector for the preparation of cell cultures. Data demonstrate that the injection of the matrigel biopolymer supplemented with interleukin-8 (IL-8) in the leech Hirudo medicinalis can be used to purify cell populations showing the same morphofunctional and molecular mechanisms of specific populations of vertebrate hematopoietic precursor cells involved in tissue repair. These cells spontaneously differentiated into myofibroblasts. This approach highlights how the innovative use of a cytokine-loaded biopolymer for an in vivo cell sorting method, applied to a simple invertebrate model, can be a tool for studying myofibroblast cell biology and its regulation, step by step.     

Enhanced skin wound healing by a sustained release of growth factors contained in platelet-rich plasma

Platelet-rich plasma (PRP) contains growth factors that promote tissue regeneration. Previously, we showed that heparin-conjugated fibrin (HCF) exerts the sustained release of growth factors with affinity for heparin. Here, we hypothesize that treatment of skin wound with a mixture of PRP and HCF exerts sustained release of several growth factors contained in PRP and promotes skin wound healing. The release of fibroblast growth factor 2, platelet-derived growth factor-BB, and vascular endothelial growth factor contained in PRP from HCF was sustained for a longer period than those from PRP, calcium-activated PRP (C-PRP), or a mixture of fibrin and PRP (F-PRP). Treatment of full-thickness skin wounds in mice with HCF-PRP resulted in much faster wound closure as well as dermal and epidermal regeneration at day 12 compared to treatment with either C-PRP or F-PRP. Enhanced skin regeneration observed in HCF-PRP group may have been at least partially due to enhanced angiogenesis in the wound beds. Therefore, this method could be useful for skin wound treatment.     

Photopolymerized Cellulose Acetate/Poly(Acrylic Acid) Semi-IPN Films for Wound Dressing Applications

In this work, semi-IPN films, composed of cellulose acetate(CA) and crosslinked poly(acrylic acid), have been synthesized via benzophenone (BP) induced free radical photo-polymerization of acrylic acid (AAc) in the presence of dissolved cellulose acetate (CA) using N,N’ methylene bisacrylamise (MB) as the crosslinking agent. The mechanical properties were tested for the films having different compositions of MB, CA and AAc in the feed mixtures. The tensile strength (TS) and percent elongation (PE) were found to increase with a concentration of CA in the films, but showed decreasing trends with concentrations of CA in the films. However, with AAc content in the films, the TS increased and PE showed just the opposite trend. The film samples were also studied for water vapor and oxygen permeation studies. The water vapor transmission rate (WVTR) decreased with MB and CA contents, but showed an increasing trend with AAc contents in the films. Finally, a representative sample showed fair antibacterial and antifungal action against E. coli and Aspergillus flavus when studied using the ‘Zone of inhibition method’.     

Preparation and Application of Quaternized Chitosan- and AgNPs-Base Synergistic Antibacterial Hydrogel for Burn Wound Healing

Infection is the major reason that people die from burns; however, traditional medical dressings such as gauze cannot restrain bacterial growth and enhance the healing process. Herein, an organic- and inorganic-base hydrogel with antibacterial activities was designed and prepared to treat burn wounds. Oxidized dextran (ODex) and adipic dihydrazide grafted hyaluronic acid (HA-ADH) were prepared, mixed with quaternized chitosan (HACC) and silver nanoparticles to fabricate Ag@ODex/HA-ADH/HACC hydrogel. The hydrogel, composed of nature biomaterials, has a good cytocompatibility and biodegradability. Moreover, the hydrogel has an excellent antibacterial ability and presents fast healing for burn wounds compared with commercial Ag dressings. The Ag@ODex/HA-ADH/HACC hydrogel will be a promising wound dressing to repair burn wounds and will significantly decrease the possibility of bacterial infection.