带作用的群系的临界结构

在本文中，我们讨论了带作用群的群系的临界结构，给出了处理允许某些作用群的群的问题的一般方法，作为应用，我们特别给出了关于幂零群及ｐ－幂零群的一些结果。     

A myelin-specific contrast agent for magnetic resonance imaging of myelination

Myelination is one of the most fundamental biological processes in the development of vertebrate nervous systems. Abnormal or disrupted myelination occurs in many acquired or inherited neurodegenerative diseases, including multiple sclerosis (MS) and various leukodystrophies. To date, magnetic resonance imaging (MRI) has been the primary tool for diagnosing and monitoring the progression of MS and related diseases; however, any change in signal intensity of conventional MRI reflects a change only in tissue water content, which is a nonspecific measure of the overall changes in macroscopic tissue injury. Thus, the use of MRI as a primary measure of disease activity was shown to be disassociated from the clinical outcome due to the lack of specificity for myelination. In order to increase the MRI specificity for myelin pathologies, we designed and synthesized the first Gd-based T(1) MR contrast agent (MIC) that binds to myelin with high specificity. In this Communication, we demonstrate that MIC localizes in brain regions in proportion to the extent of myelination. In addition, MIC possesses promising MR contrast properties, which allow for direct detection of myelin distribution through T(1) mapping in the mouse brain.     

A generalization of Hall-Higman's reduction theorem

In this paper, we generalize the Hall-Higman's reduction theorem by dropping the restrictive hypothesis (|G|, |H|)=1 and determine the detailed structure ofG.Supported in part by NSCF and Guangdong STCF. The author deeply thanks Professor Chen Zhongmu for his kind advice and help.     

聚酰胺-胺型树枝状大分子及其衍生物在基因传递中的应用

基因治疗通过基因载体将治病基因导入病患的特异细胞以治疗心血管、神经系统疾病和癌症等。寻找安全高效的非病毒基因载体一直是基因治疗以及生物材料领域中的前沿课题。聚酰胺-胺型(PAMAM)树枝状高分子作为一类三维的、结构高度有序的新型载体,由于具有安全性好、易于修饰、携带外源基因容量大等特点,已经引起了广泛的关注。但是另一方面,合成步骤相对繁琐、后期产物纯化困难以及转染效率相对较低等问题限制了这类载体的进一步发展。本文结合本课题组的研究情况,针对如何提高PAMAM的转染效率以及增强其基因传递的靶向性等相关问题,对近几年在PAMAM树枝状分子修饰改性方面所做的一些有意义的工作进行了综述,并对前景进行了展望。     

结构力学教材中某教学内容的补充

 给出了一组平行荷载直接沿着纵梁移动时，主梁承受结点荷载作用下绝对 最大弯矩的计算方法. 从理论联系实际的角度，填补了现行结构力学教材中关于结点荷载作 用下，计算主梁绝对最大弯矩的空白. 该内容若能够写入结构力学教材，将会使现行教材中 影响线的内容安排上前后更能够良好地呼应，该问题的解决能更好地体现出影响线的工 具性地位.     

关于一些弱于仿紧性质在连续闭映射下的逆象(Ⅰ)

In this paper, we study with uniform results the preimage of which the properties will preserve the same property under the continuous closed mapping whicd possess certain quite weak condition, for σ-metacompctness, θ-refinability, weakly θ-refinability, paralindel?fness, metalindelofness,δθ-refinability, weakly δθ-refinability, mesocompactness and sequentially mesocompactness, and so on. A necessary and sufficient condition about preimage problem, with uniform results, has been given in this paper; and therefore the results in D.K.Burke′s survey paper [4] have been strengthened in ihis paper.     

On Frobenius' conjecture

By using the classification theorem of finite simple groups, we have shown that “IfG is a finite group,H is a coprime operator group ofG, C _G(H)≤S(G), thenG is solvable.” As a direct corollary, we have completely proved the long-standing conjecture on fixed-point-free automorphism group. The author is grateful to Professor Chen Zhongmu for his supervision.     

关于允许一个无不动点自同构群的有限群的可解性

关于允许一个无不动点自同构(群)的有限群的可解性的猜想是有限群研究中的一个重要问题。结果比较丰富的是限制该自同构群为一个p-群的情形。Thompson于1959年证明了p阶群的情形。Martineail于1971年证明了初等Abel p-群的情形。Rickman于1979年证明了p²阶群的情形。本文借助Glauberman的一个定理,对p=2或3的一般情形给出了肯定的回答。实际上是用较初等的方法证明了更为广泛一些的结论。     

正则轨道的存在性与有限群的幂零长

本文给出了一些正则轨道存在性的条件，结合Ａ．Ｔｕｒｕｌｌ的近期定理，得到了关于有限可解群的幂零长的一些结论．