载三氧化二砷的PEG—PLGA隐性纳米粒的制备及体外研究

The aim of this study was to prepare arsenic trioxide （ATO）-loaded stealth PEGylated PLGA nanoparticles （PEG-PLGA-NPs） and to assess the merits of PEG-PLGA-NPs as drug carriers for ATO delivery. PEG-PLGA copolymer was synthesized with methoxypolyethyleneglycol （Mw=5000）, D, L-lactide, and glycolide by the ring-opening polymerization method. Amorphous ATO was transformed into cubic crystal form to increase its solu-bility in the organic solvent. ATO-loaded PEG-PLGA-NPs were prepared by the modified spontaneous emulsification solvent diffusion （SESD） method, and the main experimental factors influencing the characteristics of nanopar- ticles were investigated, to optimize the preparation. To confirm the escape of PEG-PLGA-NPs from phagocytosis by phagocytes, PEG-PLGA-NPs labeled rhodamine B uptake by murine peritoneal macrophages （MPM） were analyzed by flow cytometry. The results showed that the physicochemical characteristics of PEG-PLGA-NPs were affected by the type and concentration of the emulsifiers, polymer concentration, and drug concentration. ATO-loaded PEG-PLGA-NPs, with particle size of 120.8nm, zeta potential of-10.73mV, encapsulation efficiency of 73.6%, and drug loading of 1.36%, were prepared under optimal conditions. The images of transmission electron micros-copy （TEM） indicated that the optimized nanoparticles were near spherical and without aggregation or adhesion. The release experiments in vitro showed the ATO release from PEG-PLGA-NPs exhibited consequently sustained release for more than 26d, which was in accordance with Higuchi equation. The uptake of PEG-PLGA-NPs by MPM was found to decrease markedly compared to PLGA-NPs. The experimental results showed that PEG-PLGA-NPs were potential nano drug delivery carriers for ATO.     

小火电厂低压水力除灰设计

水力除灰是以水为介质输送灰渣的系统,按其所输送的灰渣不同,可分为灰渣混除和灰渣分除。它对输送不同的灰渣适应性强,运行安全可靠,卫生条件好,没有灰尘飞扬,有利环境保护,劳动强度小,操作维护简便,节省人力、较其它除灰方式有显著的优点,因而水力除灰系统在小火电厂得到了较广泛地采用。     

低位综放工作面无端头支架的配套技术

结合实际对低位综放工作面端头支架设计、配套及使用中存在的局限性进行了分析 ,重点阐述了对低位综放工作面无端头支架时 ,相关设备配套以及巷道支护、工艺控制等技术措施 ,为生产现场提供了借鉴     

水泥土挤密桩在尖山铁矿中的应用

介绍了水泥土挤密桩的应用、施工工艺及检测方法。     

安钢高炉矿渣利用途径探讨

介绍了高炉矿渣的产生及其基本性质,从技术、市场等方面进行了分析。提出了安钢矿渣利用的途径,为矿渣的综合利用提供了参考。     

热爆式脱离器性能及试验方法研究

国内外脱离器使用问题很多,有结构方面的,也有原理设计方面的问题,脱离器没有专用技术标准,依附在避雷器标准中的主要性能要求又不能完全满足使用要求,制约了脱离器的发展.通过分析脱离器的工作原理及工作状况,提出脱离器的试验程序、试验方法及制定脱离器标准时应考虑的几个问题:脱离器标准应规定试验程序;增加I脱c耐受试验;增加脱离...     

自燃采空区耗氧-升温的区域分布特征

联立求解采空区非线性渗流、多组分气体弥散和温度场,用表征温度(数值解）表达自燃程度和氧化区域分布特征,同时考虑垮落层位上氧化的非均匀性、工作面推进度和动态边界等各影响因素.在考虑升温情况下,采空区自燃“三带”划分方法与表征温度场方法具有一致性,温度场方法表达更具体.计算得到,虽然主自燃危险区处在上游进风侧,但因垮落层位的耗氧差异,在回风边界处(上、下双层流汇流）也可能形成局部高氧浓度区.在“定向漏风供氧-煤耗氧-工作面推进”三者综合作用下,激烈氧化升温带位于高温区的前沿,形成趋于平衡的升温分布区;最高升温点处在氧浓度分布低值区.随着高温区的强烈耗氧和工作面推进移动,高氧区与高温区的分离趋势加大.