枫杨、羊蹄水浸液对钉螺肝功能的影响

用酶学速率法测定并分析了不同浓度枫杨、羊蹄水浸液对钉螺肝脏谷丙转氨酶 (GPT)、谷草转氨酶 (GOT)活力的影响 ,同时比较了两种植物的作用效果及灭螺效果 .结果显示 ,随枫杨叶水浸液浓度的升高 ,GPT、GOT酶活力随之增高 ,0 .1 %、0 .5%浓度 (质量体积分数 )与水对照无明显差异 ,1 .0 %、2 .5%显著高于水对照 .羊蹄处理之钉螺肝GPT和GOT活性随浓度升高到 1 .0 %浓度达到峰值 ,2 .5%开始下降 ;除 0 .1 %与对照无明显差异外 ,其余浓度有明显差异 .两种植物相比 ,羊蹄对两种转氨酶的影响明显大于枫杨 ,灭螺效果也较之好 .     

Structural view of cadherin-mediated cell-cell adhesion

Following the multiplication of biochemical, biophysical and structural studies describing cadherin molecules and their interactions, several ideas have emerged to explain the mechanisms of cadherin-mediated cell adhesion. Although different models were proposed for cadherin interactions, a consensus has come forth considering lateral dimerization of cadherins as being a central component of the cell-cell adhesion process. This review summarizes the recent development in structural studies of cadherins. Received 14 September 1998; received after revision 14 November 1998; accepted 16 November 1998     

A dynamic probabilistic marking approach with multi-tag for tracing ICMP-based DoS attacks

This paper presents a dynamic probabilistic marking algorithm with multiple routing address tags, which allows the victim to traceback the origin of ICMP (Internet Control Message Protocol)-based direct and reflective DoS attacks. The proposed approach makes full use of scalable data space of ICMP packet to achieve multiple information tags. The difference between this proposal and previous proposals lies in two points. First, the number of packets needed by the victim to reconstruct the attack path is greatly reduced because of three key mechanisms: multi-tag, uniform leftover probability, and tag location choice based on the module of accommodated tag numbers within a packet. Second, the true origin of both direct and reflective ICMP-based DoS attacks can be traced.     

DNA sequence and analysis of human chromosome 8

The International Human Genome Sequencing Consortium (IHGSC) recently completed a sequence of the human genome. As part of this project, we have focused on chromosome 8. Although some chromosomes exhibit extreme characteristics in terms of length, gene content, repeat content and fraction segmentally duplicated, chromosome 8 is distinctly typical in character, being very close to the genome median in each of these aspects. This work describes a finished sequence and gene catalogue for the chromosome, which represents just over 5% of the euchromatic human genome. A unique feature of the chromosome is a vast region of approximately 15 megabases on distal 8p that appears to have a strikingly high mutation rate, which has accelerated in the hominids relative to other sequenced mammals. This fast-evolving region contains a number of genes related to innate immunity and the nervous system, including loci that appear to be under positive selection--these include the major defensin (DEF) gene cluster and MCPH1, a gene that may have contributed to the evolution of expanded brain size in the great apes. The data from chromosome 8 should allow a better understanding of both normal and disease biology and genome evolution.     

Molecular mechanism for distinct neurological phenotypes conveyed by allelic truncating mutations

The molecular mechanisms by which different mutations in the same gene can result in distinct disease phenotypes remain largely unknown. Truncating mutations of SOX10 cause either a complex neurocristopathy designated PCWH or a more restricted phenotype known as Waardenburg-Shah syndrome (WS4; OMIM 277580). Here we report that although all nonsense and frameshift mutations that cause premature termination of translation generate truncated SOX10 proteins with potent dominant-negative activity, the more severe disease phenotype, PCWH, is realized only when the mutant mRNAs escape the nonsense-mediated decay (NMD) pathway. We observe similar results for truncating mutations of MPZ that convey distinct myelinopathies. Our experiments show that triggering NMD and escaping NMD may cause distinct neurological phenotypes.     

Java字节码异常处理中信息流的分析

为提高Java移动代码动态安全验证的准确性和实用性,通过分析Java字节码中异常处理的方式与流程,提出了追踪、记录异常处理中信息流的方法.采用字节码改写技术,将异常处理中信息流的相关数据封装在异常类当中,从而保证了所采取的处理对Java虚拟机的透明性,并进一步提高了动态验证的精度.