CCL18通过N-Ras/c-myc/lin28下调乳腺癌细胞miR98的表达

目的探讨CCL18是否参与了乳腺癌miRNAs的表达调控。方法采用miRNAs芯片筛查CCL18处理前后乳腺癌细胞miRNAs的表达差异,QRT-PCR和Luciferase Reporter Assay对芯片结果进行验证。瞬时转染法分别改变乳腺癌细胞miR98和c-myc的表达,应用QRT-PCR和Western blot检测c-myc和lin28 mRNA和蛋白的表达。结果 miRNAs芯片结果显示CCL18处理后乳腺癌细胞共20种miRNAs发生变化,QRT-PCR和Luciferase Reporter Assay证实CCL18下调乳腺癌细胞miR98的表达。CCL18可上调乳腺癌细胞c-myc和lin28mRNA和蛋白的表达,转染c-myc siRNAs可逆转CCL18调控lin28和miR98表达的功能。CCL18通过miR98转录后调控乳腺癌细胞N-Ras蛋白的表达。结论CCL18通过N-Ras/c-myc/lin28通路下调miR98,下调的miR98通过转录后调控增加N-Ras蛋白的表达,从而进一步激活c-myc/lin28通路,维持miR98的持续降低,形成了一个正反馈环路。     

定制Win98优化系统性能

从存储管理、桌面和菜单、网络优化设置几方面，介绍几种优化Ｗｉｎ９８配置的常用方法。     

DIAGNOSTIC VALUE OF SERUM PROGRP31-98 IN PATIENTS WITH SMALL-CELL LUNG CANCER

Small celllungcancer (SCLC )isasubtyperepresentingapproximately 15 %to 2 0 %ofallpri marylungcarcinomaoccurringinChina .Ingener al,SCLCishighlysensitivetochemotherapyandhasafrequenttendencytometastasizeatanearlystage .Thus ,itisveryimportanttomakeanearlydiagnosisforthetreatmentofSCLC patients .NSEhaslongtermbeenusedasSCLCearlydiagnosismarkerinclinic[1] .However ,therelativelyhighfalse positiveratehasforcedthedoctorstolookforthemorespecificandsensitivemarker[2 ] .SincePro gastrin relea…     

基于Windows 98的脉直流牵引电动机试验自动测控系统

扼要叙述了脉直流牵引电动机试验自动测控系统的基本组成和原理，介绍了软件的主要功能，重点阐述了数据采集，开关控制，模拟量调节控制，数据库管理和报告处理等功能的软件设计思想，运行情况表明该系统完全满足电机试验要求。     

Web数据库建立和访问的实现

作者主要介绍如何利用VB、SQL数据库建立大中型企业的数据库,并利用Web的浏览技术在Web站点上进行动态查询及修改,并可根据所需可方便地建立各种管理子系统,用户界面也可做到很友好。     

船舶轴带发电机自动合闸及动力负荷自起动设计

在论述船舶轴带发电机DW98断路器的跳闸和合闸特性的基础上,设计了当因负载故障跳闸时通过PC控制选择性地自动合闸,及当船舶动力负荷恢复供电后又能自起动的综合系统,该设计具有很好的实用性．     

Experiences with Competitive Tendering of Bus Services in Germany

Abstract

After a long transition period with only a few isolated procedures for competitive tendering, the market for German public transport bus services has seen numerous such tenders in recent years. The results are complex. From the public transport authorities’ point of view, the main effects are a decrease in subsidy payments, with relatively low expenses relating to the tendering process (allocation, contract management). The overall level of competition is high, with five to seven bidders on average, although this has been declining in recent years. Entry barriers have been identified at significant levels for several parameters, especially with respect to the volume tendered and the revenue risk to be borne by the operator out of net‐cost contracts. Demonstrably small‐ and medium‐sized transport operators have been able to increase their market share in the starting phase of introducing tendering, with diminishing success rates in recent years. Due to the increased quality requirements in competitive tendering, the quality of public transport available has improved considerably, and environmental standards have been better implemented and sustained. As far as employees are concerned, a trend towards wages below the wage rate of private operators cannot be observed. However, their level is well below the level of public incumbent operators.