Frequency of the mtDNA 9-bp deletion in Chinese ethnic groups

The 9-bp deletion in the COII/tRNA(Lys) intergenic region (region V) of human mitochondrial DNA was screened in 1521 Chinese from 16 ethnic groups and 9 Hen geographic groups. The highest frequency was found in populations of Miao (32.4%) and Bouyei (30.8

The Acquisition of an Inheritable 50-bp Deletion in the Human mtDNA Control Region Does Not Affect the mtDNA Copy Number in Peripheral Blood Cells

The mitochondrial DNA (mtDNA) control region is believed to play an important biological role in mtDNA replication. Large deletions in this region are rarely found, but when they do occur they might be expected to interfere with the replication of the molecule, thus leading to a reduction of mtDNA copy number. During a survey for mtDNA sequence variations in 5,559 individuals from the general Chinese population and 2,538 individuals with medical disorders, we identified a 50-bp deletion (m.298_347del50) in the mtDNA control region in a member of a healthy Han Chinese family belonging to haplogroup B4c1b2, as suggested by complete mtDNA genome sequencing. This deletion removes the conserved sequence block II (CSBII; region 299-315) and the replication primer location (region 317-321). However, quantification of the mtDNA copy number in this subject showed a value within a range that was observed in 20 healthy subjects without the deletion. The deletion was detected in the hair samples of the maternal relatives of the subject and exhibited variable heteroplasmy. Our current observation, together with a recent report for a benign 154-bp deletion in the mtDNA control region, suggests that the control of mtDNA replication may be more complex than we had thought. Hum Mutat 31:538-543, 2010. (C) 2010 Wiley-Liss, Inc.

基于ICA和BP网络的电流传感器相位差测量方法

提出了一种高精度在线测定电流传感器相位差的方法.在输入端加入测试信号,在输出端采用独立分量分析(ICA)将该测试信号与传感器正常工作的输出信号分离,通过比较该测试信号输出前后相位的变化确定传感器的相位差.但因ICA算法固有的局限性,同一混合信号每次分离结果误差不同,为了提高分离精度,利用BP网络学习分离结果中相位误差与最大似然指标和负熵的关系,提出了一个指示分离结果误差的评价量,以选取多次分离结果中的最优结果.实验结果证明该评价量的有效性.

基于BP神经网络的系统级电源管理算法

在深入研究目前国际上比较流行的几种系统级电源管理（PM）算法的基础上，利用BP神经网络的非线性映射能力，提出基于BP神经网络的、对任务之间相互间隔时间也就是系统空闲时段的长度进行自适应学习的BPPM算法，具有传统回归PM算法不可比拟的优点。仿真实验表明引入神经网络的电源管理算法较之传统PM算法大大降低了系统级功耗。实现了在不需要建立系统模型、无需预先获得负载统计特性的前提下，通过从系统正常工作产生的数据中不断学习，使系统具有自适应、高效的电源管理能力，以达到降低系统功耗、提高器件可靠性、延长工作寿命的目的。

An improved BP algorithm for pattern recognition

An improved BP algorithm for pattern recognition is proposed in this paper. By a function substitution for error measure, it resolves the inconsistency of BP algorithm for pattern recognition problems, i.e. the quadratic error is not sensitive to whether the training pattern is recognized correctly or not. Trained by this new method, the computer simulation result shows that the convergence speed is increased to treble and performance of the network is better than conventional BP algorithm with momentum and adaptive step size.

碳离子辐射引起Hela细胞线粒体DNA 4977 bp的缺失

背景:线粒体DNA4977bp缺失的累积对衰老的多细胞动物来说是一个显著的特征,同时也与各种肿瘤细胞的转移和凋亡有关。目前的研究已证明辐射可特异性地诱导此缺失的产生,有望将其作为新的DNA水平的辐射损伤生物剂量标记。目的:用聚合酶链反应方法检测碳离子辐射引起的Hela细胞线粒体DNA4977bp突变缺失,并观察碳离子辐射剂量及辐射时间与线粒体DNA4977bp缺失的相关性。设计、时间及地点:细胞DNA水平的对照实验,于2008-10/11在甘肃省兰州市近代物理研究所完成。材料:人宫颈癌细胞Hela细胞株。方法:Hela细胞经2～8Gy的碳离子辐射后,于2～24h各个时间点分别提取包含线粒体DNA的全基因组DNA,并用聚合酶链反应法扩增线粒体DNA4977bp缺失的特异片段,通过限制反应模板浓度和聚合酶链反应循环数的方法进行定性分析。主要观察指标:碳离子辐射剂量及辐射时间对线粒体DNA4977bp缺失的影响。结果:经2Gy辐照处理的Hela细胞在2,4,8,24h4个时间点的检测中均无聚合酶链反应阳性产物,8Gy辐照处理的Hela细胞在12,16,24h3个时间点可检测到线粒体DNA4977bp缺失,且随时间延长而累积。辐照后12hHela细胞在8Gy辐照处理后可检测到线粒体DNA4977bp缺失,辐照后16和24hHela细胞在6,8Gy辐照处理后可检测到线粒体DNA4977bp缺失。结论:碳离子辐射引起的Hela细胞线粒体DNA4977bp缺失存在剂量相关性,且其累计程度可能与辐射时间有关。