Comparison of modified injection molding and conventional machining in biodegradable behavior of perforated cannulated magnesium hip stents

In this study,perforated cannulated magnesium(Mg)hip stents were fabricated via modified Mg injection molding and conventional machining,respectively.Additionally,the stent canal was filled with paraffin to simulate injection of biomaterials.The microstructure,mechanical performance,corrosion behavior,and biocompatibility were comparably studied.Scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS)showed higher affinity of interstitial element such as oxygen and carbon as consequences of routine molding process.After immersion in SBF,machining stents showed reduced degradation rate and increased deposition of calcium phosphate compared to molding stents.Corrosion resistance was improved via paraffin-filling.Consistently,the hemolysis and in vitro osteoblast cell culture models showed favourable biocompatibility in machining stents compared to molding ones,which was improved by paraffin-filling treatment as well.These results implied that the feasibility of the prepared machining stents as the potential in vivo orthopaedic application where slower degradation is required,which could be enhanced by designing canal-filling injection of biomaterials as well.     

基于GPRS的小型水文信息采集系统研究

水文资料在水利行业中起着非常重要的作用,在我国西部地区水文数据传输方面与发达国家相比还有较明显的差距。寻求一种经济、快速、稳定、可靠的水文信息传输系统是我国西部水文采集工作的当务之急。通过对基于51单片机的GPRS水文数据无线传输系统的软件和硬件设计,提出了硬件设计简单、投资经济、运行维护方便的小型GPRS水文信息采集系统方案．为西部地区积累丰富、详实的水文资料提供了有力保障。     

龙滩水电站砂石料系统工艺布置的经验与教训

龙滩水电站大坝混凝土工程砂石料系统由中南勘测设计研究院与葛洲坝砂石拌和研究所联合设计,葛洲坝集团公司与广西水电工程局组成的葛桂联营体承建并运行,为龙滩水电站大坝混凝土工程生产所需人工砂石骨料。对该系统与以往其他系统工艺布置相比的成功与不足进行了总结,以供今后类似工程建设借鉴。     

关于推进怒江流域水能资源开发的思考

从本世纪初开始,围绕开发水能资源促进怒江流域地区经济社会发展等问题曾引发了一场大讨论。通过讨论,大家一致认为：怒江流域地区的发展不能再继续等待下去,应以切实可行的步伐向前推进。结合工作实践,简要回顾了怒江水能资源开发前期工作情况,畅谈了从怒江开发讨论中得到的有益启发,对现阶段怒江中下游水能资源开发的相关工作提出了若干建议。     

临地铁全回转干成孔灌注桩承载力特性实例分析

本文依托工程实例北京市海淀区某紧邻地铁的全回转干成孔灌注桩项目,综合试验场地工程水文地质条件,对临近地铁的全回转干成孔灌注桩进行了研究.文中详细介绍了设计参数的选取及试验过程,通过对比泥浆护壁施工的灌注桩的试验数据,包括试桩承载力、变形以及摩阻力的分析,总结不同深度土层摩阻力曲线变化规律,进一步阐明了影响紧邻地铁的全回...     

Molecular Mechanisms of Parthanatos and Its Role in Diverse Diseases

Differential evolution of apoptosis, programmed necrosis, and autophagy, parthanatos is a form of cell death mediated by poly(ADP-ribose) polymerase 1 (PARP1), which is caused by DNA damage. PARP1 hyper-activation stimulates apoptosis-inducing factor (AIF) nucleus translocation, and accelerates nicotinamide adenine dinucleotide (NAD⁺) and adenosine triphosphate (ATP) depletion, leading to DNA fragmentation. The mechanisms of parthanatos mainly include DNA damage, PARP1 hyper-activation, PAR accumulation, NAD⁺ and ATP depletion, and AIF nucleus translocation. Now, it is reported that parthanatos widely exists in different diseases (tumors, retinal diseases, neurological diseases, diabetes, renal diseases, cardiovascular diseases, ischemia-reperfusion injury...). Excessive or defective parthanatos contributes to pathological cell damage; therefore, parthanatos is critical in the therapy and prevention of many diseases. In this work, the hallmarks and molecular mechanisms of parthanatos and its related disorders are summarized. The questions raised by the recent findings are also presented. Further understanding of parthanatos will provide a new treatment option for associated conditions.     

横向液货补给索道-软管的强迫振动数值分析

考虑索道倾斜角度、鞍座位置、索道跨距等因素影响,对舰船横向液货补给索道-软管动力学问题进行研究.基于静力学原理得到各鞍座位置索道及软管受力情况,进而将横向液货补给系统索道-软管动力学问题简化为具有多个集中质量索道系统的动力学问题.基于Galerkin原理,对偏微分动力学模型进行高阶模态截断,并对典型工况下系统动力学特性进行分析.研究表明,系统存在周期、混沌等典型复杂动力学特性.重点分析了索道跨距、阻尼等对系统动力学特性的影响.     

多源地理矢量数据要素解码方法研究

历史测绘地理信息数据格式繁杂,给数据共享与应用带来了困难,地理矢量数据要素解码过度依赖第三方平台,存在兼容性差、低可扩展性、特殊要素解码不完备等缺陷。为此,研究提出了基于Teigha及GDAL/OGR的多源地理矢量数据要素解码方法,实现了不依赖第三方平台的地理信息图件与数据解码,满足了多源矢量数据集成的数据访问、共享与格式转换需求。     

基于微机械惯导的管道多功能内检测系统研发

管道中心线测绘坐标是管道完整性管理的重要基础数据.针对小口径油气输送管道中心线测绘对小尺寸惯性导航系统的需求及现有管道内检测技术存在不足的问题,提出了一种基于微机械惯导的管道中心线测绘与基于永磁扰动检测的管道内检测技术,研发了小口径管道多功能内检测系统.该系统体积小、结构简单、能耗低、操作方便.现场工程应用中,测绘结果...