Gene product expression of cyclin D<Subscript>2</Subscript> and p16 during the transition from cardiac myocyte hyperplasia to hypertrophy

The current study was to investigate mRNA expression of cyclin D₂ and p16 during the transition from cardiac myocyte hyperplasia to hypertrophy. Cultured cardiac myocytes (CM) and fibroblasts (FC) obtained from 1-day-old Sparague-Dawley rats were used in this study. We have determined (1) hyperplasia by cell growth curve and fluorescence activated cell sorting (FACS); and (2) ultrastructure by electron microscope observation; and (3) expresions of cyclin D₂ mRNA and p16 mRNA by using in situ hybridization and image analysis. The results were shown (1) Results of cell growth curve and FACS analysis showed CM could proliferate in the first 3 cultured days (4 days in postnatal development). But the ability decreased quickly, concomitant with the differentiation. (2) The ultrastructure of CM showed the large amount of myofilaments and mitochondrion and FC showed moderate amount of rough endoplasmic reticulum. (3) The expression of cyclin D₂ mRNA in 3−, 4−, 5−day CM group was 0.89 times (p<0.05), 0.80 times (p<0.05) and 0.56 times (p<0.01) of that in 1-day group respectively. P16 mRNA in 2−, 3−, 4−, 5−day CM group were 1.63 times (p<0.01), 1.72 times (p<0.01), 1.99 times (p<0.01) and 2.84 times (p<0.01) of that in 1−day group respectively. It can be concluded that cultured neonatal rat cardiac myocytes could proliferate during the first 3 cultured days, but the ability of proliferation decreased, from the fourth day, concomitant with differentiation. Cyclin D₂ and p16 have the key roles during the transition from myocyte hyperplasia to hypertrophy. Biography: Zhang Yu-xia (1974-), female, Master, research direction: cardiovascular pathology.     

论结构化范型到面向对象范型的转变

说明在计算机软件工程方法学研究和软件产业中正在实现由传统的结构化范型到面向对象范型的转变，分析这种转型的表现、内涵及意义，指出在学校教育和继续教育中应受到高度重视，采取相应对策。     

基于IPv4网络的IPv6过渡解决方案

在分析IPv6针对IPv4几个主要问题解决方案的基础上,详细论述了从IPv4到IPv6的两个过渡技术,即双协议栈技术和隧道技术。给出了在实际组网中运用这两种技术实现向IPv6过渡的具体方案。     

Study on precipitation and transition mechanisms from the magnetic properties of silicon steel during annealing

Precipitates play an important role in determining the mechanical and magnetic properties of silicon steel. This paper aims to investigate the growth kinetics of precipitates in commercial silicon steel by analyzing its magnetic properties during isothermal annealing at 200℃. The growth of precipitates was studied by optical microscopy, scanning electron microscopy, transmission electron microscopy, and magnetic measurements. In combination with the coercive field and initial susceptibility, this technique offers the advantage of being non-destructive and providing quantitative information about the number, mean radius of precipitates, and fraction of transformation. An observed decrease in the number of precipitated particles indicates that the transformation starts from particles of appreciable initial size.     

现场总线向工业以太网过渡的一种中间实现

将工业以太网和普通以太网进行了对比 ,分别说明了对目前工业控制中的几种工业控制网络的实现方式 ,提出了一种适合于工业控制的现场总线向工业以太网过渡的一种方式 ,介绍了这种方式的特点、适用情况和优缺点。     

IPv4向IPv6过渡技术

目前,IPv4在Internet上占统治地位,随着Internet的发展,IPv4中存在的问题日渐暴露,IPv6诞生了.但IPv4与IPv6并不兼容, 研究IPv4向IPv6过渡技术,解决IPv4与IPv6共存问题, 使IPv6最终代替IPv4.     

Hybrid fracture and the transition from extension fracture to shear fracture

Fracture is a fundamental mechanism of material failure. Two basic types of brittle fractures are commonly observed in rock deformation experiments--extension (opening mode) fractures and shear fractures. For nearly half a century it has been hypothesized that extension and shear fractures represent end-members of a continuous spectrum of brittle fracture types. However, observations of transitional fractures that display both opening and shear modes (hybrids) in naturally deformed rock have often remained ambiguous, and a clear demonstration of hybrid fracture formation has not been provided by experiments. Here we present the results of triaxial extension experiments on Carrara marble that show a continuous transition from extension fracture to shear fracture with an increase in compressive stress. Hybrid fractures form under mixed tensile and compressive stress states at acute angles to the maximum principal compressive stress. Fracture angles are greater than those observed for extension fractures and less than those observed for shear fractures. Fracture surfaces also display a progressive change from an extension to shear fracture morphology.     

露天转地下最佳开采模式

建立露天转地下开采模式综合评判模型,运用层次分析法和模糊数学的基本原理对多种开采模式进行评判优选.评判优选过程中,综合考虑影响露天转地下开采模式的动态、静态、定量、非定量指标,如技术、经济指标及边坡稳定程度等:将待选择方案指标转换成隶属度矩阵,通过层次分析法得到各因素权重向量;从而建立模糊综合评判模型,利用模糊数学原理计算出各方案基于影响因素的综合优越度.以石人沟铁矿为例,4种开采模式的优越度分别为45.82％,84.32％,89.88％,80.75％,从而确定第3种方案最优.     

IPv4向IPv6过渡的机制

IPv4在Internet的高速发展中出现了许多急待解决的问题,如地址不足,路由表膨胀,安全性不高及移动性不够灵活等。新一代IPv6协议则提供了一些新的机制来解决这些问题。本文主要讨论了IPv6的特性以及IPv4向IPv6过渡的方法。     

转型中的中国食品安全问题研究

中国食品安全问题不仅与产品,更与消费者和政府有关。首先因为食品传输网络复杂性的增加,食品来源的可追溯性就降低了,消费者和生产者之间就产生了不对称信息。其次,食品工业发展不完善且严重依赖于高度不集中的传统小农生产。第三,因为食品生产的信息不对称,消费者普遍对生产工艺存在认知差距,因此消费者,特别是城市居民,一般不懂如何选择可靠安全的食品。在食品之间没有显著质量差别的情况下,他们往往倾向于选择更低价的食品。在这种体系下,三个要素显著影响食品质量:食品工业的分散性本质降低食品的可追溯性;政府执行的不成熟不完善的条例没能充分阻止不合格的产品进入市场;消费者对食品加工过程的无意识也使得他们依据食品的价格标签而做出错误的选择。食品问题的解决办法不能只靠政府或者有良知的企业,而是三种因素都应得到改善。     

三门峡王官与武威沙沟黄土记录中的末次间冰期向末次冰期转换期的暖性回返事件

河南三门峡王官剖面与甘肃武威沙沟剖面捕捉到了末次间冰期向末次冰期转换时期发生于72 ka前后持续时间约为2 ka的一暖性回返事件,两剖面的冬、夏季风替代指标对该暖性回返事件的反应在时间上大致同步(其时间段约为71～73 ka,在71.4～72.1 ka前后该暖性回返事件最强盛),暗示该暖性回返事件在东亚季风区可能是一普遍存在的气候突变事件.鉴于该暖性回返事件在全球其他地区的海洋、陆地、冰芯记录中也有较普遍的反映,我们认为该事件很可能是一次发生于气候转型期的全球普遍存在的暖性突变事件.     

资源枯竭型城市转型过程中的政府职能转变

资源枯竭型城市经济转型是一个世界性的难题,能否解决由于资源枯竭带来的经济、社会问题,是对资源枯竭型城市的政府能力提出的前所未有的挑战。根据资源产业与资源型城市的发展规律,资源枯竭型城市必然要经历建设—衰退—转型振兴或消亡的过程。因此,这些城市都面临着如何寻找新的出路问题,而如何转变资源枯竭型城市政府的经济职能与社会职能又是顺利进行经济转型工作的关键所在。     

资源枯竭型城市转型过程中的政府职能转变

资源枯竭型城市经济转型是一个世界性的难题, 能否解决由于资源枯竭带来的经济、社会问题, 是对资源枯竭型城市的政府能力提出的前所未有的挑战.根据资源产业与资源型城市的发展规律, 资源枯竭型城市必然要经历建设-衰退-转型振兴或消亡的过程.因此, 这些城市都面临着如何寻找新的出路问题, 而如何转变资源枯竭型城市政府的经济职能与社会职能又是顺利进行经济转型工作的关键所在.     

Comparison of sensible and latent heat fluxes during the transition season over the western Tibetan Plateau from reanalysis datasets

The sensible and latent heat fluxes during the transition season over the western Tibetan Plateau from the NCEP-1 (NCEP/NCAR Reanalysis 1), AR-II (NCEP-DOE Reanalysis 2) and ERA40 reanalysis datasets were compared and analyzed. The results show that the phase change in soil moisture has a significant effect on the sensible and latent heat fluxes over the western Tibetan Plateau (TP) due to the freezing–thawing processes during the transition from the dry to the wet period. The uncertainties in the sensible and latent heat fluxes over the western TP are quite high in the reanalysis data, and depend largely on the success of the soil moisture simulations in the models. Improving the hydrological process simulations in the land-surface models in seasonally frozen ground and in the active frozen soil layer may be an effective way of enhancing the reliability of the surface heat fluxes from the reanalysis data over the Tibetan Plateau.     

杜鹃红山茶花药愈伤组织的诱导

杜鹃红山茶花蕾经4℃低温预处理5～15 d后,用不同消毒剂进行表面消毒.以花药为外植体,MS为基本培养基,研究低温预处理下,花蕾表面消毒方法以及2,4-D与KT、NAA浓度组合对杜鹃红山茶花药愈伤组织诱导的影响.结果表明:4℃低温预处理花蕾的最佳时间为5 d,花蕾的最佳消毒方法为75%乙醇浸洗30 s后,用0.1%升汞消毒10 min;诱导花药愈伤组织的适宜培养基为MS+1.0 mg/L 2,4-D+0.5 mg/L KT和MS+0.5 mg/L2,4-D+0.4 mg/L NAA,于23～25℃暗培养30 d,愈伤组织诱导率分别达34.44%和35.33%.     

从IPV4向IPV6过渡的隧道技术

本文研究探讨了从IPV4向IPV6过渡的过程中，用于解决IPV6小岛之间通信的各种隧道技术，并对它们的实现机制和路由开销做了比较。     

IPv4与IPv6转换研究

针对IPv4面临的问题，阐述了IPv6的产生、相对于IPv4其巨大的优势和未来的发展趋势。并介绍了IPv4到IPv6的过渡的必要性、过渡技术方案，如：双协议栈、隧道和网络地址协议转换等，以及目前对IPv6的支持、可采用的策略与试验平台和研究方案。未来的工作方向是确认一种平滑的过渡策略，必须先在逐渐扩大的试验床上试用成功，不致于对现有的网络造成严重的后果。     

从形式化规范自动生成系统级状态机

形式化方法能精确、无二义地描述软件规范,但其可读性、可理解性差以及缺乏有效的自动测试工具.鉴于此,提出一种新的方法将支持面向对象开发的形式化语言所描述的软件规范自动地转化为系统级状态机,从而改善其可读性与可理解性.实际应用表明,这种方法可以提高形式化规范的可读性与可理解性.     

Induction of c-fos during myelomonocytic differentiation and macrophage proliferation

Previous studies have suggested a role for c-fos in cellular differentiation in fetal membranes, haematopoietic cells and teratocarcinoma stem cells. In other cell types, such as fibroblasts, c-fos expression is normally very low, but is rapidly induced by peptide growth factors, implicating c-fos in growth control mechanisms. Here, we show that the TPA (12-O-tetradecanoylphorbol-13-acetate)-induced macrophage-like differentiation of HL60 human promyelocytic precursor cells is accompanied by the induction of both c-fos mRNA and protein within 15 min after treatment, suggesting a functional role for c-fos in this differentiation system. In quiescent terminally differentiated macrophages, expression of c-fos is inducible by the macrophage-specific growth factor colony-stimulating factor-1 (CSF-1). The kinetics of c-fos induction, however, are entirely different from those in growth factor-stimulated fibroblasts, supporting the view that the c-fos gene product may serve different functions in different cell types.     

“楼市新政”下如何实现住宅地产向商业地产过渡

通过介绍当前的房地产市场背景,得出房企转型的必然性;然后通过对商业地产一系列开发程序论述转型的可行性;最后得出转型必要并且可行,以期为房地产企业提供一定的参考.