用加端PCR技术改造h－IGF－1cDNA

用ＤＮＡ合成仪合成了分别带有ＰｓｔＩ位点和ＳａｌＩ位点及终止密码子的２个用于扩增ｈＩＧＦ－１ｃＤＮＡ的ＰＣＲ引物．利用合成的引物，７００ｂｐ长的ｈＩＧＦ－１ｃＤＮＡ模板和Ｔａｑ聚合酶进行ＰＣＲ扩增．扩增产物经电泳鉴定后克隆进Ｍ１３ｍｐ１８载体，进行核苷酸序列分析．结果显示：ＰＣＲ产物含已发表的ｈＩＧＦ－１成熟蛋白的编码序列和５＇端的ＰＳｔＩ位点及３＇端的ＳａｉＩ位点及终止密码ＴＡＧ．用加端ＰＣＲ技术成功地扩增和改造了ｈＩＧＦ－１的编码序列．     

M序列报文的MIAC压缩编码算法

M序列报文是典型短波数据链报文。提出一种针对M序列报文的MIAC压缩编码算法,该算法根据M序列报文的统计特性,应用基于字段结构的半动态概率估计模型,量化低概率符号出现概率的取值且半动态更新,采用动态的编码区间长度更新机制,使乘法运算替换为预处理过程中的查表运算,最大造成10.04%的编码效率损失。测试结果表明,当M序列报文数目为2~9条时,MIAC压缩编码算法在损失最多20%的压缩率时,使压缩时间低于原算术编码至少50%。为今后研究提升数据链系统性能提供一种新的思路。     

Evidence for splicing of interrupted immunoglobulin variable and constant region sequences in nuclear RNA.

Evidence is presented that the mouse light-chain coding sequence is interrupted in a 27S nuclear RNA species, whereas the sequence is continuous in both a 13S nuclear RNA and in cytoplasmic mRNA. The discontinuity of coding regions in the 27S nuclear RNA parallels the situation found in myeloma DNA and indicates, therefore, that the removal of interruptions in the V and C regions occurs at the level of nuclear RNA.     

一种改进Logistic混沌序列安全网络编码设计

针对多源组播带宽利用率较低和构造算法收敛时间过长的不足,提出了确定线性逐层构造算法.该方案只需通过一次试播,即可逐层构造各个编码节点的编码系数,并对出现数据冗余的链路进行修剪枝操作,最终使信宿端接收到的全局编码矩阵满秩,从而顺利解码.针对网络编码中的全局窃听攻击和污染攻击,从密码学角度出发,提出了一种基于混沌序列的安全网络编码方案,通过改进Logistic混沌序列对原始消息的最后一维数据进行加密,并利用m序列扰动混沌序列构造全局编码矩阵,实现将加密的原始信息与全局编码矩阵线性组合进行传输并在信宿端点构造线性列表,对污染信息进行过滤.通过仿真与数据分析可得:该方案提高了多源组播的通信效率,在抵抗全局窃听攻击的同时,还可以滤除污染信息,使网络的安全性进一步得到提高.     

Retroviral gag and DNA endonuclease coding sequences in IgE-binding factor gene

Immunoglobulin-binding factors are known to regulate the synthesis of B-cell-derived immunoglobulin heavy-chain isotypes. Cloning and nucleotide sequence determination of complementary DNA encoding rodent IgE-binding factors (IgE-BF) revealed that messenger RNA encodes a glycoprotein of 557 amino acids which is expressed as a precursor of relative molecular mass (Mr) 60,000 (60K) in COS7 monkey cells. We report here that the 3' two-thirds of the IgE-BF coding sequence shows a surprising homology (72%) at the DNA level with coding sequences of the gag and pol (DNA endonuclease) genes of the Syrian hamster intracisternal A particle (IAP H18), an endogenous retrovirus. This marked homology demonstrates that the rodent gene encoding IgE-BF is a hybrid gene which evolved very recently by integrating genes of viral origin, and that the encoded polypeptide comprises three separate domains: an IgE-BF domain and retrovirus-derived gag and DNA endonuclease-like domains. This may represent the first report of a cellular gene containing a virus-derived coding sequence.     

Generation of beta-globin by sequence-specific proteolysis of a hybrid protein produced in Escherichia coli

High-level expression of many eukaryotic genes has proved difficult to achieve even when a strong promoter and the ribosome binding sequence from highly expressed Escherichia coli genes have been placed in front of the coding sequences. To overcome this problem, many eukaryotic proteins have been efficiently produced as hybrids after fusion of their genes with a coding sequence of E. coli genes. However, such hybrid proteins are not suitable for functional studies or clinical use unless the authentic protein sequence can be released by specific cleavage. Here, we have inserted the sequence Ile-Glu-Gly-Arg between the 31 amino-terminal residues of lambda cII protein and Val 1 of human beta-globin, and produced this hybrid in high yield in E. coli. We then cleaved the hybrid specifically at the single arginine, using blood coagulation factor Xa and thus liberated the authentic beta-globin chain. As factor Xa is specific for the tetrapeptide Ile-Glu-Gly-Arg, which is rare in protein sequences, our expression/cleavage system is applicable to the efficient production of many eukaryotic proteins.     

一种基于新仿射变换的修正分形序列图像的编码方法

分形编码技术应用于序列图像编码中 ,基于新仿射变换对分形序列图像的编码方法作了修正 ,并给出其有效性的证明 .     

基于Fibonacci-Lucas序列构造大围长QC-LDPC码的方法

基于斐波那契-卢卡斯序列并结合三角旋转法提出一种围长至少为8的斐波那契-卢卡斯准循环低密度奇偶校验(fibonacci-lucas quasi-cyclic low-density parity-check, F-L-QC-LDPC)码的构造方法。该方法所构造的F-L-QC-LDPC码不存在四环和六环,计算复杂度低,硬件实现简单且节省硬件存储空间,具有优秀的纠错性能。仿真结果表明,当误码率(bit error rate,BER)为10-6时,该方法所构造的码长为2 700且码率为0.5的码型,相较于基于Fibonacci数列并结合三角旋转法构造的同码长码率的QC-LDPC(2 700,1 352)码,净编码增益(net coding gain,NCG)提高了约1.0 dB,相较于基于卢卡斯数列大围长构造方法构造的QC-LDPC(2 700,1 353)码,NCG提高了约1.6 dB。且同样条件下,该方法构造的码长为2 580且码率为0.5的码型与基于等差数列构造的QC-LDPC(2 580,1 292)码相比,NCG提高了约1.0 dB。     

基于超基性机制的5G网络信道安全编码方案

为解决当前5G信道安全编码方案中存在的编码复杂、传输性能较差及数据冗余度高的不足,提出了一种基于超基性机制的5G网络信道安全编码方案。首先,利用5G信道编码过程中的极化序列具有的正交特性,通过模二运算和张量积运算来实现序列特征矢量的极化分割,有效降低5G信道编码过程中冗余比特数量,高效调度传输序列,提升网络信道安全编码效率。随后,考虑5G信道矫正比特序列具有的极化性质,通过正交权向量映射方法,设计二次编码极化方法,用于降低信道预发射过程中存在的冗余码元数量,改善码元拥塞现象,提高信道发射效率,具有较高的信道码元基性极化率。仿真实验表明:与当前常用的时间片分支累积算法(Time Slice Branching Accumulation,TSB算法)、信道最低分割度编码算法(Channel Minimum Segmentation Coding Algorithms,CMSC算法)相比,本文算法具有数据传输带宽高、时间片误比特数低、编码速率快、周期重传次数少等特性,具有很强的实践部署价值。     

一种新的快速H.263算法的研究

利用了桌面视频会议中人物图像序列的独有特点,提出了一个新的在图像序列中快速检测与跟踪面部的算法,通过对序列中人脸的快速跟踪与位移检测,动态地调节序列中不同运动幅度图像的矢量搜索范围．实验结果表明,对于类似于Ｍｉｓｓ这样的头肩部图像序列,在不明显影响主、客观图像质量和压缩比的情况下,该方法能够有效提高Ｈ．２６３的编码速度     

The genome sequence and structure of rice chromosome 1

The rice species Oryza sativa is considered to be a model plant because of its small genome size, extensive genetic map, relative ease of transformation and synteny with other cereal crops. Here we report the essentially complete sequence of chromosome 1, the longest chromosome in the rice genome. We summarize characteristics of the chromosome structure and the biological insight gained from the sequence. The analysis of 43.3 megabases (Mb) of non-overlapping sequence reveals 6,756 protein coding genes, of which 3,161 show homology to proteins of Arabidopsis thaliana, another model plant. About 30% (2,073) of the genes have been functionally categorized. Rice chromosome 1 is (G + C)-rich, especially in its coding regions, and is characterized by several gene families that are dispersed or arranged in tandem repeats. Comparison with a draft sequence indicates the importance of a high-quality finished sequence.     

彩色视频的四维MDCT及矩阵量化编码

对赵岩的彩色视频的四维矩阵模型理论及压缩编码研究中的量化方法进行了改进,提出了矩阵量化的方法。矩阵量化克服了矢量量化码书敏感的问题,而且该方法不需要训练码书,不需要预测和运动补偿,易于快速实现。四维矩阵量化之后,又给出了进行变长编码时所需要的扫描顺序。变长编码后进行Huffman编码,这与经典的压缩方法是一致的。     

Altered nucleotide sequences of a translocated c-myc gene in Burkitt lymphoma

The nucleotide sequence of a translocated c-myc gene in a Burkitt lymphoma reveals multiple base changes in the coding region. Twenty-five base changes, generating 16 codon alterations, were found in the first coding exon; no changes occur in the second coding exon. These changes are probably the result of somatic mutations that occurred during and after translocation, and may contribute to oncogenesis by allowing synthesis of an altered c-myc gene product.     

绿豆防御素基因的克隆、序列分析和植物表达载体的构建

从绿豆叶片提取总DNA中,通过PCR方法扩增出362bp的具有多种抗病、抗虫特性的绿豆防御素基因, 并将其克隆到pGM-T easy vector,酶切图谱及DNA 测序分析表明克隆的片段包含了完整的绿豆防御素基因的编码序列,与原序列同源性达到99.5%,蛋白质同源性达到100%.此基因编码的多肽由73个氨基酸组成,含有28个氨基酸的信号肽和8个半胱氨酸,可形成4个二硫键.我们用此基因构建了高效植物表达载体pBin438-LD.     

一种基于核苷酸二联体的DNA序列编码规则

序列比较的基本任务有:(1)对于两条长度相近的序列相似,找出序列的差别;(2)判断一条序列的前缀与另一条序列的后缀相似;(3)判断一条序列是否是另一条序列的子序列;(4)判断两条序列中是否有非常相似的子序列.对核苷酸二联体给出DNA序列一种编码规则,利用异或操作进行序列比较.     

基于块分割和上下文模型的视频编码算法

树结构的构造适合小波图像编码,但并不适合视频编码,利用熵编码原理,提出了视频图像编码算法,先将每帧的残差补偿到原始序列,并通过块分割编码和上下文模型进行视频编码.研究结果表明：该算法在视觉质量、算法性能和编码效率上要优于传统的视频编码算法.     

IEEE802.11b中补码键控技术

目的研究一种高速直接序列扩频方法———补码键控调制方式CCK(ComplementaryCode Keying)。方法首先介绍补码序列的定义、性质、产生方法以及使用多相补码的CCK调制解调的实现,然后以传输速率11 Mbps时的补码序列为例,使用Matlab软件对CCK调制的编码增益进行仿真分析。结果 CCK调制不仅能为系统带来处理增益,同时可以为系统带来一定编码增益,并且具有较高的频谱利用率。结论 CCK调制是一种理想的调制方式,已被广泛地应用于无线通信系统中。     

黄角苔叶绿体rbcL基因编码区的序列分析

测定了黄角苔（Ｐｈａｅｏｃｅｒｏｓｌａｅｖｉｓ（Ｌ．）Ｐｒｏｓｋ）叶绿体ｒｂｃＬ基因编码区的１３９８个核苷酸序列,并且由此推导出对应的氨基酸序列．此基因中密码子的第２和第３位上Ａ／Ｔ所占的比例较高,分别为５３６％和７７５％．黄角苔ｒｂｃＬ基因的编码区与花旗松、菠菜、玉米和雷氏衣藻间在核苷酸序列上的同源性分别为８４０％,８１５％,７９３％和７６３％;在氨基酸序列上的同源性分别为９１．０％,８９．９％,８８．５％和８９．３％．为研究角苔植物的系统发育提供了核苷酸序列方面的资料．     

基于动静背景下的视频对象自适应提取算法

在MPEG-4标准中提出了VOP(Video Object Planes)的概念,可以通过VOP实现基于内容的操作。这样,从场景中自动地分割出视频对象就成为基于对象视频编码的先决条件。为此,提出一种基于动静背景下的视频对象自适应提取算法。该算法可以自动提取动态背景、静态背景,也可以在视频序列中出现背景和对象都停止变化时实现视频对象的提取。同时,该算法引入了视频前景和背景预处理,克服了由于视频图像对比度低造成的提取出的部分视频对象轮廓不完整的问题。