Comparison of osteogenesis between two kinds of stem cells from goat combined calcium phosphate cement in tissue engineering

To explore the possible mechanism of osteogenesis for deciduous teeth stem cells (DTSCs) in vivo/ vitro, stem cells from goat deciduous teeth (SGDs) were firstly isolated, induced and transplanted into immunocompromised mice. The SGDs’s mineralization pattern and osteogenesis were compared with bone marrow messenchymal stem cells (BMMSCs) from goats. SGDs have similar osteogenic differentiation pattern in vitro and bone-like tissue formation mechanism in vivo to BMMSCs; moreover SGDs have stronger alkaline phosphatase (ALP) gene expression and osteopontin (OPN) gene expression levels than BMMSCs; also SGDs can form more bone-like tissues than BMMSCs when cell-scaffold compounds are transplanted into immunocompromised mice. This pre-clinical study in a large-animal model confirms that DTSCs may be an appropriate source of stem cells in repairing bone defects with tissue engineering.     

新农村建设视阈下红色旅游资源的保护与开发

我国广大农村有着丰富的红色旅游资源.在新农村建设中,红色旅游资源保护与开发的现状却令人堪忧.建议在新农村建设中,充分发挥政府的主导作用,在拆除农村老屋时应加大对红色旅游资源的保护力度,要正确处理好经济社会发展与红色旅游资源保护的关系,将红色旅游资源保护与开发与建设和谐新农村有机结合起来.     

不同温度下沥青混合料劈裂强度的影响因素

以常用的AC-25沥青混合料为研究对象,应用正交试验设计与统计分析方法,展开了2.36,4.75,2.36与0.075mm筛孔通过率、油石质量比5个影响因素的不同温度劈裂强度分析,结果表明:各影响因素对不同温度下劈裂强度值的影响没有随温度改变而发生排序变化,排序大小为2.36mm通过率>0.075mm通过率>13.2mm通过率>油石质量比>4.75mm通过率.其中,2.36mm通过率高度显著影响不同温度劈裂强度值,且随温度逐渐升高,影响程度越加明显,表明级配对不同温度下劈裂强度起控制作用,优化级配设计可显著提高不同温度的劈裂强度值.     

高速公路运营收入预测软件的开发

高速公路运营收入预测是高速公路企业进行财务评价的基础,根据交通量和收费标准相结合的预测方法,用V isual Basic编制的小程序实现高速公路基年和未来年运营收入的快速预测,从而结束了手工计算的估算方式,大大提高了工作效率。     

爆炸作用下钢绞线斜拉索破坏模式和剩余承载性能试验

为研究爆炸荷载作用下斜拉桥钢绞线斜拉索的破坏模式和剩余承载性能,开展了8根15.7-7钢绞线斜拉索试件的野外爆炸试验以及爆炸损伤钢绞线的静力轴向拉伸试验,得到了钢绞线斜拉索在接触爆炸及近距离爆炸作用下的破坏形态和损伤钢绞线的剩余承载力;并根据断丝数量和承载力损失定量比较了高密度聚乙烯护套(HDPE)、单层钢管护套(SST)、双层钢管护套(DST)以及泡沫铝夹层钢管护套(FAFST)4种不同防护措施的抗爆防护效果。研究结果表明：在接触/近距离爆炸作用下,钢绞线斜拉索的损伤破坏主要表现为正对爆炸作用区域部分钢丝断裂和局部横向变形;采用FAFST防护可以有效地改善钢绞线斜拉索的破坏程度,HDPE防护效果有限;相较于无防护的祼索,SST与DST防护反而加剧了斜拉索试件的损伤程度;爆炸损伤钢绞线的剩余承载力与剩余钢丝数量成正比。基于试验结果和回归分析方法,提出了爆炸损伤钢绞线斜拉索剩余承载力评估的实用公式,可以在爆炸灾害后根据钢绞线断丝破坏情况,快速评估斜拉索的剩余承载能力。     

提升沥青路面抗水损害能力措施综述

水损害是道路工程领域持续关注的问题。为了提升沥青路面抗水损害能力,缓解沥青路面水损害,该文综合梳理了国内外相关文献,在分析水损害机理的基础上,对提升沥青路面抗水损害能力措施进行了总结与评价。结果表明:合理选择原材料,添加抗剥落剂,优化路面结构、控制施工质量等措施均可以提高沥青路面抗水损害能力,但应根据具体的情况综合考虑加以选择,才能相得益彰。     

管道切入工程

在中港三航局承担的科威特国舒艾拜油码头修复工程中，由于不能影响油码头的正常生产，所以管道的切入工程是危险性最大的项目。在无施工经验可借鉴、不具备按常规工艺施工所需条件的情况下，工程技术人员设想了冷切割、封堵、区隔的施工方案，经细化后进行实施，取得了圆满的结果。     

Long-term tracking based on spatio-temporal context

Aiming at the problem that the fast tracking algorithm using spatio-temporal context (STC) will inevitably lead to drift and even lose the target in long-term tracking, a new algorithm based on spatio-temporal context that integrates long-term tracking with detecting is proposed in this paper. We track the target by the fast tracking algorithm, and the cascaded search strategy is introduced to the detecting part to relocate the target if the fast tracking fails. To a large extent, the proposed algorithm effectively improves the accuracy and stability of long-term tracking. Extensive experimental results on benchmark datasets show that the proposed algorithm can accurately track and relocate the target though the target is partially or completely occluded or reappears after being out of the scene.     

A programmable calculation procedure for number of traffic conflict points at highway intersections

Traffic movement conflict points at intersections are the points at which traffic movements intersect (including crossing, merging, and diverging). Numbers and distribution of different types of conflict points are used to evaluate intersection access management designs and safety performance. Traditionally, the determination of the numbers of conflict points for different traffic movements is based on manual methods, which causes the difficulty for computerized procedures to evaluate safety performance of different access management designs. Sometimes, a programmable calculation procedure may provide more effective solutions as compared with manual methods. This paper presents a programmable calculation procedure for the determination of the numbers of conflict points, which could be used as a basis for a computerized procedure. Concepts of virtual movement lanes and intersection quadrants are introduced to specify types of intersections, traffic lane configurations, and traffic movement regulations. Calculation models, based on such concepts, for traffic movement conflict points at signalized and unsignalized intersections can be obtained. In support of the procedure, case studies are presented in the paper. The procedure presented in the paper can be programmed into a computer program for the purpose of a computerized evaluation of intersection safety and design performance of different access management or control approaches. Copyright © 2012 John Wiley & Sons, Ltd.     

重庆市两江新区疏唐互通立交方案设计浅析

重庆市两江新区基础设施快速建设,港口、码头、铁路、公路、城市道路之间相互交叉影响,以疏唐互通立交为例,浅述如何解决各项基础设施建设之间的矛盾,确保项目的顺利实施。