Early Expression of Tet1 and Tet2 in Mouse Zygotes Altered DNA Methylation Status and Affected Embryonic Development

Ten-eleven translocation (Tet) dioxygenases can induce DNA demethylation by catalyzing 5-methylcytosine(5mC) to 5-hydroxymethylcytosine(5hmC), and play important roles during mammalian development. In mouse, Tet1 and Tet2 are not expressed in pronucleus-staged embryos and are not involved in the genomic demethylation of early zygotes. Here, we investigated the influence of Tet1 and Tet2 on methylation of parental genomes by ectopically expressing Tet1 and Tet2 in zygotes. Immunofluorescence staining showed a marked 5hmC increase in the maternal pronucleus after injection of Tet1 or Tet2 mRNA into zygotes. Whole-genome bisulfite sequencing further revealed that Tet2 greatly enhanced the global demethylation of both parental genomes, while Tet1 only promoted the paternal demethylation. Tet1 and Tet2 overexpression altered the DNA methylation across genomes, including various genic elements and germline-specific differently methylated regions. Tet2 exhibited overall stronger demethylation activity than Tet1. Either Tet1 or Tet2 overexpression impaired preimplantation embryonic development. These results demonstrated that early expression of Tet1 and Tet2 could substantially alter the zygotic methylation landscape and damage embryonic development. These findings provide new insights into understanding the function of Tet dioxygenases and the mechanism of DNA methylation in relation to embryogenesis.     

原料润磨对造球和焙烧过程的影响

通过生产试验,研究了原料润磨比对生球强度的影响,在实验室进行了不同温度的焙烧试验,测量了原料不同润磨比时球团矿的常温抗压强度,研究了球团矿氧化焙烧过程中热态强度的变化规律.     

含短纤维胎面胶的混炼工艺

介绍了含短纤维胎面胶的混炼工艺,分析了在混炼过程中短纤维在橡胶中的混合分散模型.指出当短纤维-橡胶复合材料处于最佳黏度状态时,混炼效果最佳.     

改进BP网络及其在传感器非线性校正中的应用

针对传统BP网络收敛速度慢、容易陷入局部最小点等问题,采用附加动量因子和自适应学习速率进行了改进,并将其用于对传感器的非线性误差进行补偿.用MATLAB语言编制相应的训练程序,仿真结果表明,在相同的条件下,改进后算法节省了大量的训练时间,同时提高了数据拟合的精度.     

基于自动检焦信号梯度信息的自适应平滑算法研究

近年来随着航空相机技术不断发展,高分辨率相机将成为未来航空相机的发展趋势;但环境的变化会使光学系统的性能发生显著的、随机的变化,因此,欲在恶劣的环境条件下获得最佳分辨率,必须使相机具有很高的检焦精度,然而由于测量元件及电源等的噪声的存在,大大影响了检焦信号精度;基于中值滤波和梯度信息的平滑滤波算法,介绍了一种新的自适应平滑算法,该算法有效地抑制扰动信号,更为真实的突现出峰值信号,从而大大提高了检焦精度;该方法大大减小了随机干扰对检焦结果的影响,提高了检焦精度,从而每次都能获得较为清晰的图像。     

图像扫描波动性定量标准及分形扫描矩阵的快速生成

在图像扫描技术中，首要的问题是如何尽量减小生成数据的波动性。本文在深入研究各种扫描技术的基础上，定义了一种描述扫描产生数据波动性的度量指标，基于图像存在局部连续性，证明了Hilbert分形曲线扫描优于其他传统扫描，表明在生成数据的最佳连续特性，并通过实验 分析了图像扫描方式对DCT变换编码效果的影响。最后，给出了一个构造Hilbert扫描矩阵的快速算法。     

ptp通讯在锌电解供电优化系统中的研究与应用

以提高锌电解供电系统的自动化程度、实现网络控制为目的,在分析了系统总体结构和控制原理的基础上,重点讨论了ptp通讯在系统中的研究与应用;ptp通讯网络以S7-300PLC为主站,以两台晶闸管数字触发器为从站,实现电流给定和触发角反馈等信号的传输,其通讯协议简单,开发成本低,与Profibus网一道组成的控制网抗干扰能力强,可靠性高,有力地保证了锌电解供电优化系统安全运行,为锌电解提高整流效率、节约电能提供了保障.     

Future home design: an emotional communication channel approach to smart space

Smart spaces use human–computer interfaces (HCIs) to improve how humans experience their surroundings. However, HCIs are sometimes less user-friendly and intuitive than their traditional counterparts. Our research aims to use every-day objects to create communication channels between spaces and people, which can then strengthen interpersonal emotional relationships through a natural and unobtrusive interface. This study explores how using simpler instruments such as a whiskey glass, a table, and an MP3 player to interact with a dwelling improves user experience in a HCI-equipped smart space. We implemented a real smart space—the Time Home Pub, which not only adjusts the environmental atmosphere (such as background lighting, music, and photos) in response to human activities but also encourages a better connection between humans, their memories, and physical space. Time Home Pub was exhibited at the Taipei Fine Arts Museum in 2007 for the topic of Architecture of Tomorrow. Preliminary evaluations by visitors demonstrate the satisfactory feasibility of the system and how a smart space could change and improve human experiences through the use of new technology and architectural design elements.     

舰船消磁可视化界面设计与实现

随着测磁和消磁硬件设备的快速发展,急切需要先进的测、消磁软件与之配合来高效地完成消磁任务,提出了基于虚拟仪器设计软件LabWindows/CVI和科学计算软件Matlab开发舰船消磁可视化界面的整体软件结构,推导了从实际测量深度到标准测量深度的磁场换算算法,通过Active技术实现两种软件接口调用,分析了舰船磁场的可视化描述和特征信息提取方法;在LabWindos/CVI平台下开发了舰船消磁可视化界面,调用Matlab完成磁场换算和数据预处理,充分利用了两种软件的优势;整体界面美观、操作方便、附加多种有用功能,实现了友好的人机交互。     

模糊知识粒度计算与应用

根据自反模糊关系,将知识粒度的概念推广为模糊知识粒度.考虑传统模糊粗糙集的粗糙性度量和相似性度量,忽略了模糊集的粗糙近似处于不同知识粒度背景中这样一个重要因素,结合模糊知识粒度的计算,提出了模糊粗糙集的粗糙性度量和相似性度量的新方法.最后,在一个实际的模糊信息系统中,给出了基于模糊知识粒度的知识约简算法.