51种昆虫足的爬行粘附结构研究

利用扫描电子显微镜(SEM)对7目51种昆虫足的粘附结构进行超微形态观察.根据形态和着生位置,共发现光滑型、刚毛型和吸盘3大类粘附结构.光滑型粘附结构可以进一步划分为光滑型中垫、光滑型爪垫和光滑型跗垫;刚毛型粘附结构可划分为跗节刚毛型粘附底面、刚毛型爪垫和爪间突、海绵窝,以及跗节棘特化的粘附结构等;吸盘是龙虱科昆虫特化的吸附结构.在目级阶元上,粘附结构的类型及形态具有显著差异,可作为分类鉴定及系统发育研究的重要特征.     

Effects of hydraulic pressure on cardiomyoblasts in a microfluidic device

We employed a microfluidic device to study the effects of hydraulic pressure on cardiomyoblast H9c2. The 170 mm Hg pressure increased the cellular area and the expression of atrial natriuretic peptide. With the same device, we demonstrated that the effects of hydraulic pressure on the cardiomyoblast could be reduced by the inhibitor of focal adhesion kinase. This mechanical–chemical antagonism could lead to a potential therapeutic strategy of hypertension-induced cardiac hypertrophy.     

Microwells support high-resolution time-lapse imaging and development of preimplanted mouse embryos

A vital aspect affecting the success rate of in vitro fertilization is the culture environment of the embryo. However, what is not yet comprehensively understood is the affect the biochemical, physical, and genetic requirements have over the dynamic development of human or mouse preimplantation embryos. The conventional microdrop technique often cultures embryos in groups, which limits the investigation of the microenvironment of embryos. We report an open microwell platform, which enables micropipette manipulation and culture of embryos in defined sub-microliter volumes without valves. The fluidic environment of each microwell is secluded from others by layering oil on top, allowing for non-invasive, high-resolution time-lapse microscopy, and data collection from each individual embryo without confounding factors. We have successfully cultured mouse embryos from the two-cell stage to completely hatched blastocysts inside microwells with an 89% success rate (n = 64), which is comparable to the success rate of the contemporary practice. Development timings of mouse embryos that developed into blastocysts are statistically different to those of embryos that failed to form blastocysts (p–value < 10⁻¹⁰, two-tailed Student''s t-test) and are robust indicators of the competence of the embryo to form a blastocyst in vitro with 94% sensitivity and 100% specificity. Embryos at the cleavage- or blastocyst-stage following the normal development timings were selected and transferred to the uteri of surrogate female mice. Fifteen of twenty-two (68%) blastocysts and four of ten (40%) embryos successfully developed into normal baby mice following embryo transfer. This microwell platform, which supports the development of preimplanted embryos and is low-cost, easy to fabricate and operate, we believe, opens opportunities for a wide range of applications in reproductive medicine and cell biology.     

智能化能否提升企业全要素生产率和技术创新

数字化、网络化和智能化是“中国制造业2025”提出的产业转型的重要方针,而智能化技术作为一种通用技术进步,是否能够真的缩短劳动时间,提高企业全要素生产率和技术创新还值得商榷。本文基于中国工信部、国家发改委和科技部的智能化试点政策,使用 2009-2018年上市公司面板数据,采用倾向得分匹配和双重差分方法（PSM-DID）,研究智能化政策能否促进企业的全要素生产率和创新效率,并分析要素密集度、所有权结构和研发密度产生的异质性。研究结果发现：（1）智能化能够提高当期的企业全要素生产率,但对企业创新效率的影响不明显;（2）智能化对企业全要素生产率和技术创新的影响均存在滞后性和动态性,对全要素生产率的影响呈“U”型趋势,而对企业创新效率的作用从第二年才开始,并呈倒“U”型趋势;（3）考虑要素密集度、所有权结构和研发密度后,智能化对不同类型企业影响不同。简单来说,智能化对劳动和资源密集型企业全要素生产率的作用大于资本密集型,而创新效率相反。国有企业智能化对全要素生产率的作用大于非国有企业,并且创新效率的作用都不显著。研发密度越低的企业智能化对全要素生产率作用最大,但对所有类型企业当期创新效率的影响都不显著。     

有关教育导航网站的思考

随着教育资源数据数量、内容和形式的几何级的速度增长,网络教育资源的组织和管理日益成为人们关注的焦点。导航网站的作用得到越来越多的网民肯定的同时,也为教育资源的组织和管理提供了参考。     

英语成语中色彩词汇的文化特征

英语中由色彩词汇构成的成语使用广泛，形象生动，语言洗炼，富于哲理。色彩词汇与民族特定的历史、文化、生活、风俗习惯、地理环境等有着密切的联系，不同的历史文化、地域文化、习俗文化产生出不同的文化特征的色彩词汇成语。了解和弄清这些成语的文化特征，是学习和研究色彩词汇的前提。     

“体质健康”思辨

通过比较和分析体质、健康等概念,并从中探讨体质与健康的关系,发现词语“体质”不适合与“健康”结合在一起使用.作为《国家学生体质健康标准》用语,“体质健康”一词对于健康的理解意义不大,不宜继续作为官方正式语言使用.     

不同海拨地域环境学生身体素质的差异研究

对海南省陵水黎族自治县黎族、西藏自治区拉萨市藏族学生进行了调查、测试,取得了大量学生体质健康数据资料.以调研取得的数据为基础,对海南黎族、西藏藏族7 ～18岁学生的身体素质进行统计分析,找出两个民族学生在身体素质方面的差异,进而以学校体育为媒介,采取有效的措施,改善学生身体素质方面的不足,全面增强学生体质.     

中华武学与中医经络体系

中华武学的理论根基是中医学经络学说,它们之间可以起到相互促进的作用,应加强研究中华武学与中医学经络学说的关系,促进中华武学和中医运动学的发展,以求培养高层次人才。