节点干预对无尺度细胞信号转导网络的影响

在数学建模的基础上研究了无尺度细胞信号转导网络的拓扑结构属性及节点干预对信号网络的影响。结果表明不同类型节点干扰所导致的网络紊乱的范围和程度具有明显的差异。此研究不仅对于认识和理解细胞信号系统复杂性、结构与功能的关系具有重要意义,而且也为复杂系统的研究提供了一种新思路。     

Amelogenin gene splice products: potential signaling molecules

The amelogenins, the major proteins of the developing tooth enamel matrix, are highly conserved throughout most species studied. The gene structure is similar, with a set of seven exons and intervening introns, and remarkable conservation of particular exon sizes over divergent species. Studies of exon skipping and consequent alternative gene splicing suggest that, in vertebrates, exon definition is crucial. In this mechanism, exon size is important. If too small, an exon can be readily skipped, if too large, internal cryptic splice sites may be utilized. Other factors, such as intron length and specific nucleotide sequences at the splice boundaries also modulate splicing efficiency, but amelogenin gene splicing conforms well to the generalized exon length model. Exons 1, 2 and 7 are not subject to splicing that affects the secreted protein product, but exons 3, 4 and 5 are at the lower boundary of exon size, rendering them, 4 and 5 especially, subject to skipping. On the other hand, exon 6 is very long and has cryptic splicing sites that can be used. In the mouse, nine distinct splice product proteins have been detected. The question now is the functions of these products. The larger forms, those that contain the intact proline-rich, hydrophobic exon 6 domains, are important for enamel mineralization. Recent work suggests that the small proteins resulting from deletion of a major part of amelogenin gene exon 6 via utilization of a cryptic site may have signal transduction functions during tooth development. Furthermore, new work also suggests that odontoblasts transiently express the small amelogenins during the period that epithelial-mesenchymal signaling between preodontoblasts and preameloblasts determines the course of tooth development. The same peptides have been demonstrated to act on non-odontogenic cells and effect their phenotypic expression patterns in vitro, and to induce bone formation in implants in vivo. Received 20 March 2002; received after revision 2 July 2002; accepted 3 July 2002     

The odd couple: signal transduction and endocytosis

Cell surface receptors are used to transmit extracellular information. The activation of cell surface receptors initiates signal transduction and receptor endocytosis. Signal transduction and the endosomal transport of activated receptors require precise regulation. New concepts for the integration of endocytosis and signaling arise from recent findings that suggest bidirectional interplay of these two processes. This review discusses the following questions: (i) do activated cell surface receptors modify the endosomal system to promote internalization and endosomal traffic, and (ii) do internalized cell surface receptors use specifically localized signaling complexes to generate specific biological signals?     

LRC的非相干最大似然相位增量序列估值

非相干最大似然相位增量序列估值是一种利用连续相位调制信号的相位增量序列进行最大似然序列估值的方法,其误码性能通常远优于常规的非相干解调,有时甚至接近于相位解调。本文着重研究几种二进制LRC信号的最大似然相位增量序列估值。     

信令追踪在日常维护工作中的应用研究

信令追踪是通过对交换机内部、局间信令流进行跟踪和分析，发现局数据缺陷、信令负荷异常、话务不均衡等系统故障产生的原因，是交换机日常维护的重要手段之一。作者通过具体实例，以探讨信令追踪在日常维护工作中的应用。     

GSM移动信令网中移动应用部分（MAP）的监测

介绍了GSM移动信令网中移动应用部分(MAP)的监测问题，主要讨论了MAP分层结构，MAP信令协议分析及移动业务分析。针对MAP的分层格式，着重介绍了其由事务处理能力层(TCAP)向MAP层的解码过程，给出了流程图，并结合实例分析了解码结果。在建立在底层解码的基础上的移动分析中，给出了包括呼叫建立号码，统计及呼叫故障统计的实现过程实测情况。MAP信令监测系统的实现对更好地维护管理GSM信令网，优化GSM网络提高网络的运行质量都是不可缺少的。实测结果对MAP信令检测系统的实现有一定的参考价值。     

移动七号信令集中监测系统中消息过滤的实现

消息过滤的实现对获得完整的信令规程分析，实现网络故障精确定位，有重要意义。给出了移动七号信令集中监测系统中消息过滤的参数，介绍了消息过滤实现的设计思想，最后通过实例对消息过滤的功能进行了分析。     

智能光网络中的网元管理

由于在智能光网络中引入控制平面,网元管理需要同时支持控制平面和管理平面的接入。该文针对这种变化,参照Client-Server模型设计了将网络管理接口和连接控制接口整合在一起的网元管理服务器。据此提出了一个分布式、多接口、支持并发接入的智能光网络网元管理解决方案,并在中国第一个具有自动交换光网络功能的光网络实验床上得到了验证。其业务中断时间在保护模式下最短达到89ms,而在恢复模式下可达300ms以下。     

No.7信令系统及其在程控交换机中的应用

介绍了程控交换机中的No.7信令系统软硬件配置及维护，并结合科研实践分析了不同交换机之间开通No.7信令时遇到的问题及处理方法。