针对混凝土板桩在干粗砂地基中的静压贯入问题,为了明确贯入过程中的挤土效应及贯入阻力的发展规律,利用离散元数值模拟软件EDEM(Engineering Discrete Element Method)对干粗砂中混凝土板桩静压贯入过程进行了三维数值模拟。为此,提出...针对混凝土板桩在干粗砂地基中的静压贯入问题,为了明确贯入过程中的挤土效应及贯入阻力的发展规律,利用离散元数值模拟软件EDEM(Engineering Discrete Element Method)对干粗砂中混凝土板桩静压贯入过程进行了三维数值模拟。为此,提出了适用于类似试验的参数标定方法,分析了贯入过程中颗粒的运动特征。针对板桩结构的特点,对长边和短边方向的挤土效应进行了对比,并以短边为例,分析了不同高度处的挤土效应。最后,根据颗粒与桩结构的接触力,提取了桩端阻力和桩侧摩阻力的值,分析了两者在贯入过程中的变化规律。结果显示:在贯入过程中,颗粒的运动呈现"涡流状",并随贯入过程演化;板桩沿短边方向的表面隆起量约为沿长边方向的隆起量的2倍;随着长宽比的增加,板桩结构在短边方向和长边方向的隆起值相应增加,且短边方向的隆起值与长边方向的隆起值的比值与相应板桩的长宽比近似相等;随着贯入的进行,桩侧摩阻力所占的比重逐渐增加,在完全贯入后,侧摩阻力值约占桩端阻力的1/25;不同长宽比的板桩结构,其桩端阻力和桩侧摩阻力的单位值近似相等,并与准二维计算结果相近。展开更多
目的探讨驻南沙某岛礁官兵的身体适应性的变化及特点。方法抽取650例驻南沙某岛礁的官兵进行调查,调查项目包括基本信息、既往患病史、各系统症状出现时间、症状严重程度、持续时间、是否寻求治疗、是否明确诊断及治疗的效果。结果回收...目的探讨驻南沙某岛礁官兵的身体适应性的变化及特点。方法抽取650例驻南沙某岛礁的官兵进行调查,调查项目包括基本信息、既往患病史、各系统症状出现时间、症状严重程度、持续时间、是否寻求治疗、是否明确诊断及治疗的效果。结果回收调查问卷650份,问卷回收率为100%,参加调查者男性649例,女性1例,年龄(24.31±4.29)岁,身高(173.03±5.47)cm,体质量(77.54±37.46)kg,体质量指数(body mass index,BMI)为25.85±1228,累计驻守岛礁天数(188.82±316.04)d。在既往病史中,患有不同程度肌肉关节系统疾病较为突出,占9.23%(60例);不适症状最多的是呼吸系统症状,占42.15%(274例);神经系统及心理症状占38.31%(249例),新发肌肉骨骼系统症状占34.35%(224例),消化系统症状占29.54%(192例),心血管系统症状占14.3%(93例)。结论驻守岛礁官兵主要不适症状以呼吸系统症状、神经系统、新发肌肉骨骼系统症状为主,提示岛礁气候及环境一定程度上影响了上岛礁官兵日常生活质量和身心健康。展开更多
Cytarabine(1-β-D-arabinofuranosylcytosine, Ara-C), isolated from a Caribbean sponge species Tethyacrypta, is the first antitumor drug from a marine resource. In 1980, the US Food and Drug Administration approved this...Cytarabine(1-β-D-arabinofuranosylcytosine, Ara-C), isolated from a Caribbean sponge species Tethyacrypta, is the first antitumor drug from a marine resource. In 1980, the US Food and Drug Administration approved this drug for the treatment of different types of leukemia. This drug has a short plasma half-life, low stability, limited bioavailability, and severe side effects. To improve stability and bioavailability, we synthesized nine novel derivatives by blocking the cytarabine metabolic sites and improving lipophilicity. The c Log P values of the newly synthesized compounds were calculated. All the synthesized compounds were more lipophilic than cytarabine, resulting in membrane permeability and bioavailability improvement. The antitumor activities against leukemia cell line HL-60 were evaluated by using the MTT assay. The bioassay results revealed that the IC_(50) values of compounds 5, 8 and 9 were 0.080, 0.090 and 0.057 μmol L^(-1), respectively, which was similar with that of cytarabine(0.056 μmol L^(-1),). In comparison, compound 4 with a phosphate group at O5' was inactive. Because phosphoester bonds are easily hydrolyzed by alkaline phosphatase and are commonly used in producing prodrug strategies, compound 4 might also be metabolized in vivo and generate compound 3 or even cytarabine through a multi-step reaction. Thus, compound 4 might be a promising compound to be developed as a prodrug.展开更多
文摘针对混凝土板桩在干粗砂地基中的静压贯入问题,为了明确贯入过程中的挤土效应及贯入阻力的发展规律,利用离散元数值模拟软件EDEM(Engineering Discrete Element Method)对干粗砂中混凝土板桩静压贯入过程进行了三维数值模拟。为此,提出了适用于类似试验的参数标定方法,分析了贯入过程中颗粒的运动特征。针对板桩结构的特点,对长边和短边方向的挤土效应进行了对比,并以短边为例,分析了不同高度处的挤土效应。最后,根据颗粒与桩结构的接触力,提取了桩端阻力和桩侧摩阻力的值,分析了两者在贯入过程中的变化规律。结果显示:在贯入过程中,颗粒的运动呈现"涡流状",并随贯入过程演化;板桩沿短边方向的表面隆起量约为沿长边方向的隆起量的2倍;随着长宽比的增加,板桩结构在短边方向和长边方向的隆起值相应增加,且短边方向的隆起值与长边方向的隆起值的比值与相应板桩的长宽比近似相等;随着贯入的进行,桩侧摩阻力所占的比重逐渐增加,在完全贯入后,侧摩阻力值约占桩端阻力的1/25;不同长宽比的板桩结构,其桩端阻力和桩侧摩阻力的单位值近似相等,并与准二维计算结果相近。
文摘目的探讨驻南沙某岛礁官兵的身体适应性的变化及特点。方法抽取650例驻南沙某岛礁的官兵进行调查,调查项目包括基本信息、既往患病史、各系统症状出现时间、症状严重程度、持续时间、是否寻求治疗、是否明确诊断及治疗的效果。结果回收调查问卷650份,问卷回收率为100%,参加调查者男性649例,女性1例,年龄(24.31±4.29)岁,身高(173.03±5.47)cm,体质量(77.54±37.46)kg,体质量指数(body mass index,BMI)为25.85±1228,累计驻守岛礁天数(188.82±316.04)d。在既往病史中,患有不同程度肌肉关节系统疾病较为突出,占9.23%(60例);不适症状最多的是呼吸系统症状,占42.15%(274例);神经系统及心理症状占38.31%(249例),新发肌肉骨骼系统症状占34.35%(224例),消化系统症状占29.54%(192例),心血管系统症状占14.3%(93例)。结论驻守岛礁官兵主要不适症状以呼吸系统症状、神经系统、新发肌肉骨骼系统症状为主,提示岛礁气候及环境一定程度上影响了上岛礁官兵日常生活质量和身心健康。
基金supported by the‘Zhufeng Scholar Program’of Ocean University of China(No.841412016)the‘Outstanding Talents Plan’of Qingdao(No.15-10-3-15-(34)-zch)to Dr.Wenbao Liyouth special fund for PhD of Qingdao(No.16-5-1-61-jch)
文摘Cytarabine(1-β-D-arabinofuranosylcytosine, Ara-C), isolated from a Caribbean sponge species Tethyacrypta, is the first antitumor drug from a marine resource. In 1980, the US Food and Drug Administration approved this drug for the treatment of different types of leukemia. This drug has a short plasma half-life, low stability, limited bioavailability, and severe side effects. To improve stability and bioavailability, we synthesized nine novel derivatives by blocking the cytarabine metabolic sites and improving lipophilicity. The c Log P values of the newly synthesized compounds were calculated. All the synthesized compounds were more lipophilic than cytarabine, resulting in membrane permeability and bioavailability improvement. The antitumor activities against leukemia cell line HL-60 were evaluated by using the MTT assay. The bioassay results revealed that the IC_(50) values of compounds 5, 8 and 9 were 0.080, 0.090 and 0.057 μmol L^(-1), respectively, which was similar with that of cytarabine(0.056 μmol L^(-1),). In comparison, compound 4 with a phosphate group at O5' was inactive. Because phosphoester bonds are easily hydrolyzed by alkaline phosphatase and are commonly used in producing prodrug strategies, compound 4 might also be metabolized in vivo and generate compound 3 or even cytarabine through a multi-step reaction. Thus, compound 4 might be a promising compound to be developed as a prodrug.
