A truncated human chromosome 16 associated with alpha thalassaemia is stabilized by addition of telomeric repeat (TTAGGG)n

The instability of chromosomes with breaks induced by X-irradiation led to the proposal that the natural ends of chromosomes are capped by a specialized structure, the telomere. Telomeres prevent end-to-end fusions and exonucleolytic degradation, enable the end of the linear DNA molecule to replicate, and function in cell division. Human telomeric DNA comprises approximately 2-20 kilobases (kb) of the tandemly repeated sequence (TTAGGG)n oriented 5'----3' in towards the end of the chromosome, interspersed with variant repeats in the proximal region. Immediately subtelomeric lie families of unrelated repeat motifs (telomere-associated sequences) whose function, if any, is unknown. In lower eukaryotes the formation and maintenance of telomeres may be mediated enzymatically (by telomerase) or by recombination; in man the mechanisms are poorly understood, although telomerase has been identified in HeLa cells. Here we describe an alpha thalassaemia mutation associated with terminal truncation of the short arm of chromosome 16 (within band 16p13-3) to a site 50 kb distal to the alpha globin genes, and show that (TTAGGG)n has been added directly to the site of the break. The mutation is stably inherited, proving that telomeric DNA alone is sufficient to stabilize the broken chromosome end. This mechanism may occur in any genetic disease associated with chromosome truncation.     

(6,5)笼图(n,5)笼(n≤7)的统一

本文给出了(6,5)笼图,并且对它的正确性进行了间接地论证,同时又以同样的思想和方法给出了(5,5)笼,(7,5)笼的同构图,此时又意外地得到了(4,5)笼,于是,(3,5)笼,(4,5)笼,(5,5)笼,(6,5)笼,(7,5)笼便得到了完美地统一。     

广义第二类Stirling数S(n,n-tk,r)的一个公式

利用广义第二类Stirling数的定义,给出广义第二类Stirling数 的一个公式,更一般地给出 的一个公式．     

三路树P(m,n,n+5)是边幻图的证明

用演绎推理的方法,研究Ringel在1998年提出的树是边幻图的猜测问题,证明了三路树P(m,n,t)当t=n 5时是边幻图,部分解决了Ringel提出的猜测问题.     

关于K_（1，2，n）和K_（1，1，1，n）的优美性

分别给出了完全３部图Ｋ１，２，ｎ和完全４部图Ｋ１，１，１，ｎ的一种优美标号，从而证明了Ｋ１，２，ｎ和Ｋ１，１，１，ｎ是优美图．     

关于A(n,6)与A(n,7)的精确公式与简单显式

设A(n,k)为丢番图方程∑i=1^k ixi=n的非负整数解的个数,作者用初等方法给出A(n,6)与A(n,7)的精确公式与简单显式,从而实质上给出了整数n分为k个部分的无序分拆数P(n,6)与P(n,7)的精确公式与简单显式。     

完全三部图K（n,n,n＋k）的色性

设Ｇ为简单图,Ｐ（Ｇ,λ）为Ｇ的色多项式。若对任意简单图Ｈ满足Ｐ（Ｈ,λ）＝Ｐ（Ｇ,λ）,都有Ｈ与Ｇ同构,则称Ｇ是色唯一图,设Ｋ（ｍ,ｎ,ｒ）表示完全三部图。证明了（１）对任意非负整数ｋ,若ｎ≥ｋ＋ｋ＾２／３,则Ｋ（ｎ,ｎ,ｎ＋ｋ）是色唯;（２）若ｎ≥４,则Ｋ（ｎ,ｎ,ｎ＋４）是色唯一图。     

~（92）M_o（n，p）~（92m）Nb，~（98）M_o（n，p）~（98m）Nb和~（94）M_o（n，2n）~（93m）M_o反应截面测量

报告了Ｅｎ＝１３．４０～１４．７９ＭｅＶ中子能区用活化法以２７Ａｌ（ｎ，α）２４Ｎａ截面为中子注量标准测得的９２Ｍｏ（ｎ，ｐ）９２ｍＮｂ．９８Ｍｏ（ｎ，ｐ）９８ｍＮｂ和９４Ｍｏ（ｎ，２ｎ）９３ｍＭｏ的反应截面．还列举了尽可能收集到的数据，并将９２Ｍｏ（ｎ，ｐ）９２ｍＮｂ和９８Ｍｏ（ｎ，ｐ）９８ｍＮｂ两反应过的实验测量值与理论计算值进行了比较．中子能量是用铌锆截面比法测定的．     

An(n≥5)的单性的一个新证明

给出了一个判断含单极大子群的群为单群的条件，并且通过对这个条件的验证给出了An（n≥5）是单群的一个新的证明．     

14.8 MeV中子引起的172Yb(n,p)172Tm,173Yb(n,p)173Tm,170Yb(n,2n)169Yb和176Yb(n,2n)175Yb的核反应截面测量

用活化法以93Nb(n,2n)92mN反应截面为中子注量标准,然后对172Yb(n,p)172Tm,173Yb(n,P)173Tm,170Yb(n,2n)160Yb,176Yb(n,2n)175Yb的反应截面进行了测量,测得由(14.84±03)MeV中子引起的173Yb(n,p)172Tm的反应截面为(9.4±L0.9)mb,173Yb(n,p)173Tm的反应截面为(3.64±0.2)mb,170Yb(n,2n)169Yb的反应截面为(2 130±81)mb,176Yb(n,2n)175Yb的反应截面分别为(2169±81)mb.把测量的数据和其他作者的数据进行了比较,且利用HFTT程序计算了中子能量在7～18 MeV范围内两个(n,2n)反应和中子能区在5～30 MeV内两个(n,p)反应的截面,给出了这4个核反应的激发函数曲线.     

Morphological evolution from aquatic to terrestrial in the genus Oreolalax （Amphibia, Anura, Megophryidae）

A phylogeny of 17 species in the genus Oreolalax is reconstructed based on 21 morphological characters from adult specimens, skeleton specimens, tadpoles and eggs. Four species groups are recognized, of which the O. rugosus species group is the most primitive, the O. weigoldi species group is the second, the O. omeimontis species group is the third and the O. pingii species group is the most recently diversified. Based on the evolutional tendency of the morphological characters on the phylogenetic tree, it is proposed that the evolution of tympanum, tympanic annulus, columella, spoon-like cartilage and the web between toes reflect the habit changes from aquatic to terrestrial. Thus, Oreolalax is regarded as one important representative genus to study further the evolution of morphological characters from aquatic to terrestrial.     

(n~2,(n+1)~2)中至少有一个素数的证明

证明(n~2,(n+1)~2)中至少有一个素数,是一个众所周知的数论难题(华罗庚1979,(美)阿尔伯特·H·贝勒1998)。本文用筛法先证明一个叫做筛不完原理的定理,使用筛不完原理证明了(n~2,(n+1)~2)中至少有一个素数。还给出素数在自然数中的概率为0的一个新的证法。     

几个（n，2n）核反应激发函数的评价

用活化法测量了(n,2n)核反应截面，并利用HFTT程序对该反应截面进行了评价，作出了核反应激发函数曲线图，分析了核反应截面随中于能量的变化关系。对比结果显示，激发函数曲线与文献中的实验结果一致。     

一类2-连通(n,n+2)-图的色等价与色惟一性

图的色等价与色惟一性是用代数方法研究图论中着色问题一个有着重要意义的研究方法．关于2-连通(n，n 2)有4长圈或两个三角形，或围长为5且不与K4同胚的图族的色等价与色惟一问题已有结果．本文基于图的同胚分类和色多项式系数的比较，给出2-连通(n，n 2)围长为6又不与K4同胚的图族的色等价子族和色惟一子族．     

几个(n,2n)核反应激发函数的评价

用活化法测量了 (n ,2n)核反应截面 ,并利用HFTT程序对该反应截面进行了评价 ,作出了核反应激发函数曲线图 ,分析了核反应截面随中子能量的变化关系。对比结果显示 ,激发函数曲线与文献中的实验结果一致。     

Determination of copy number for 5S rDNA and centromeric sequence RCS2 in rice by Fiber-FISH

The copy number of 5S rDNA and centromeric sequence RCS2 was determined by extended DNA fiber based fluorescence in situ hybridization (Fiber-FISH) in rice (Oryza sativa ssp. indica cv. Guangluai No. 4) genome. In order to determine the copy number, it is necessary to know the basepair number that a given length DNA fiber contains under a microscope. Therefore, the length of two DNA fragments, in which the basepair number had been already known, was measured. The insert sequence of the tested BAC 38D17 was 136 kb and its extended DNA was 56.4 μm long, 2.41 kb/μm on average, while that of the tested BAC 44B4 was 144.5 kb in total and 55.7 μm long, 2.60 kb/μm on average under the microscope. They were very close to the theoretical value of B-DNA in the Watson-Crick DNA model, which is 2.97 kb/μm. According to the average value of basepair number per μm of the two samples mentioned above, that is, 2.51 kb/μm, it could be estimated that the copy number was about 686 for 5S rDNA and 286-1121 for the centromere sequence RCS2.