搜索结果: 16-30 共查到“理学 mutation”相关记录41条 . 查询时间(0.081 秒)
Huge progeny production during the transient of a quasi-species model of viral infection, reproduction and mutation
quasi-species model viral infection reproduction
2010/11/17
Eigen's quasi-species model describes viruses as ensembles of different mutants of a high fitness "master" genotype. Mutants are assumed to have lower fitness than the master type, yet they coexist wi...
The Birth-Death-Mutation process: a new paradigm for fat tailed distributions
The Birth-Death-Mutation process paradigm fat tailed distributions
2010/11/24
Fat tailed statistics and power-laws are ubiquitous in many complex systems. Usually the appear-ance of of a few anomalously successful individuals (bio-species, investors, websites) is interpreted as...
The statistical mechanics of a polygenic characterunder stabilizing selection, mutation and drift
statistical mechanics polygenic characterunder stabilizing selection mutation drift
2010/11/15
By exploiting an analogy between population genetics and statistical mechanics, we study the evolution of a polygenic trait under stabilizing selection, mutation, and genetic drift. This requires us ...
Species abundance distributions in neutral models with immigration or mutation and general lifetimes
Species abundance distribution Crump–Mode–Jagers process splitting tree branching process
2010/12/15
We consider a general, neutral, dynamical model of biodiversity. Individuals have i.i.d.
lifetime durations, which are not necessarily exponentially distributed, and each individual
gives birth inde...
Graded mutation in cluster categories coming from hereditary categories with a tilting object
Graded mutation cluster categories hereditary categories tilting object
2010/12/13
We present a graded mutation rule for quivers of clustertilted algebras. Furthermore, we give a technique to recover a clustertilting object from its graded quiver in the cluster category of cohX.
We define tilting mutations of symmetric algebras as the endomorphism algebras of Okuyama-Rickard complexes. For Brauer tree algebras, we give an explicit description of the change of
Brauer trees un...
Mutation-Periodic Quivers, Integrable Maps and Associated Poisson Algebras
Integrable Maps Associated Poisson Algebras
2010/4/2
We consider a class of map, recently derived in the context of cluster mutation. In this paper we start with a brief review of the quiver context, but then move onto a discussion of a related Poisson ...
Evolutionary Programming Based on Non-uniform Mutation
Evolutionary programming genetic algorithm non-uniform mutation global optimization probability convergence theoretical analysis
2013/9/9
A new evolutionary programming algorithm (NEP) using the non-uniform mutation operator instead of Gaussian or Cauchy mutation operators is proposed. NEP has the merits of \long jumps" of the Cauchy mu...
ENU诱导带LacZ靶基因的λgt11 DNA突变分子机理的初步研究①Mutation Study of λgt11 DNA with LacZ Induced by ENU
LacZ基因 突变 体外重包装 诱变剂 DNA测序
2008/1/21
摘要采用ENU(乙基亚硝基脲)作用于裸露的 λgt11 DNA，经体外重包装，转染宿主菌 E. coli Y1090，在含底物X-gal，诱导剂IPTG的选择性培养基上铺皿，发现被处理的 λgt11 DNA除了使噬菌体存活率下降外，还出现了靶基因“LacZ”较高频率的突变。其中以二甲基亚砜(DMSO)为溶剂，当存活率分别为3.5×10-3、1.6×10-3和5.5×10-4 时，相应的突变率依次为...
中国人扩张型心肌病与受磷蛋白基因关系的研究 Association between Mutation of Phospholamban Gene and Dilated Cardiomyopathy
扩张型心肌病 受磷蛋白基因 突变
2008/1/8
摘要
受磷蛋白（phospholamban）是心肌收缩的一个重要调节因子，可抑制心肌肌浆网钙ATPase的活性、降低其对钙的亲和力。正常情况下，受磷蛋白可被不同的蛋白激酶磷酸化从而解除其肌浆网钙ATPase的抑制作用。国外两个DCM家系研究发现受磷蛋白基因突变与DCM的发生有关，研究目的旨在探讨中国人群心肌特异性受磷蛋白基因突变与特发性扩张型心肌病发病的关系。收集60例确诊的特发性扩张型心肌病...
人类单纯性先天性心脏病中TBX5基因的突变及表达研究 Studies on the Mutation and Expression of TBX5 Gene in Human Simple Congenital Heart Disease
TBX5基因 心脏发育 突变 表达
2007/12/31
摘要应用PCR-DGGE方法在61个单纯性先天性心脏病核心家系共216位成员中检测TBX5基因8个外显子的突变情况；以β-actin作为内对照对单纯性先天性心脏病患者（房间隔缺损12例、室间隔缺损16例、法洛四联症6例）和3个非先天性心脏病患者（正常对照）心肌标本进行RT-PCR扩增和定量分析，观察TBX5基因在mRNA水平有无差异。研究了人类单纯性先天性心脏病患者中TBX5基因突变及表达情况。在...
大肠杆菌FC40系统静止期突变中的F因子转移The Occurrence of Actual F Factor Transfer during the Stationary-phase Mutation in Escherichia coli FC40
大肠杆菌FC40系统 适应性突变 F因子转移
2007/12/31
摘要本研究采用大肠杆菌GM133 rifr细胞和营养收集细胞HB214 strr进行适应性突变实验。在混合30min和2d 后添加链霉素杀死GM133基因型细胞，继续培养5d后，在选择平板上出现了一定数量的lac+strr基因型回复突变菌落。根据这些突变菌落的数量，估计在lac+突变产生之前，GM133和HB214细胞之间的接合频率分别为0.07%和7.47%。在培养了7d的选择平板上添加含链霉素...
人线粒体tRNALeu(UUR)基因A3243G点突变对其亮氨酰化活性的影响Effects of A3243G Point Mutation on Aminoacylation of Human Mitochondrial tRNALeu(UUR)
人线粒体tRNALeu(UUR) A3243G点突变 氨酰化 体外转录 人线粒体亮氨酰tRNA结合酶
2007/12/30
摘要化学法合成人线粒体野生型与A3243G点突变型tRNALeu(UUR)基因,体外转录生成相应的tRNALeu(UUR),表达并纯化人线粒体亮氨酰tRNA合成酶(mtLeuRS),用mtLeuRS催化野生型与突变型tRNALeu(UUR)与亮氨酸结合，分别检测两种类型tRNALeu(UUR)的氨酰化动力学常数。结果表明，野生型tRNALeu(UUR)的Km/Kcat仅为突变型tRNALeu(UU...
胃癌中APC基因I1307K突变及蛋白质表达The I1307K Mutation and Protein Expression of APC Gene in Gastric Cancer
APC基因 I1307K突变 蛋白质 胃癌
2007/12/30
摘要为探讨肿瘤抑制基因APC结构及表达异常与胃癌发生、发展的关系,采用ARMS PCR检测胃癌中APC基因I1307K突变存在与否，免疫组织化学方法分析胃癌中APC蛋白表达水平。结果表明，在 62例胃癌高发区易感人群血液标本及45例胃癌中未检测到I1307K突变；胃癌（早期、进展期）中APC蛋白表达阳性率显著低于正常黏膜，进展期胃癌中APC蛋白表达阳性率显著低于早期胃癌，淋巴结转移阳性的胃癌中AP...
拟南芥SUPERMAN基因表观突变的研究进展Progress of the SUPERMAN Epigenetic Mutation in Arabidopsis
拟南芥 SUPERMAN 甲基化 表观突变
2007/12/7
摘要本文综述了拟南芥SUPERMAN基因表观突变体clark kent（clk）的表型、基因型、DNA甲基化及表观突变机制等方面的研究进展。主要研究结果有：clk是SUPERMAN(SUP)的等位基因，能遗传但不稳定，其对称位点（CpG和CPXPG）和非对称位点的胞嘧啶高度甲基化，伴随着SUP转录水平的下降；CpG和CPXPG胞嘧啶甲基转移酶分别是METHYLTRANSFERASE1（MET1）和...