加强螺旋胶管弯曲问题的研究

曲挠性能是橡胶软管的重要质量指标之一。本文从理论方面对多层钢丝缠绕螺旋胶管的弯曲问题进行了研究，建立了管轴曲率半径与材料性质及截面几何形状间的关系。根据材料的极限变形，导出管轴临界弯曲半径的计算方法。此法对橡胶制品的设计与制造具有一定的实用价值。     

聚合物挤出成型过程的实验应力分析

为了探明高聚物熔体在模腔内的应力分布状况，提出了实验应力分析法，实验表明，大多数聚合物在熔融状态下具有暂时双折射效应，从而可借助于偏光仪聚取应力干涉条纹图，实验所得的应力条纹图与理论推导所得的曲线族是一致的。文中也给出了在多种口模处的剪应力分布情况。     

广告摄影中常见题材的拍摄与布光

摄影是一门纪实的艺术,作为视觉传达的一种表现形式,在广告中应用广泛;广告摄影必须传播真实的信息,必须具有较强的视觉冲击力和吸引力。这两个专业特征的体现要靠精度的摄影技求。摄影是一门摄影师与光线合作的艺术。观察题材和表现题材都需要光,这里论述几种常见题材的拍摄方法及用光的规律。     

非匹配条件下滑动模的鲁棒性

本文研究结构系统在非匹配条件下滑动模的鲁棒性问题，首先提出了变结构系统部分不变性的概念，进而给出了变结构系统具有部分不变性的充分必要条件；最后举一个例子验证所提出的方法，本文结果解决了不确定系统在何种条件下可以直接设计出具有期望动态品质的滑动模的问题。     

制冷循环中的损失分析计算

本文由热力过程损失导出计算制冷循环的总损失ＥＬ的表达式；并证明ＥＬ≥０．用这种分析法计算了使用非共沸工质的劳伦兹循环的总损失ＥＬＺ，并与逆郎肯循环对比．结果表明两者的制冷系数都受到工质吸热过程的平均温度和放热过程平均温度的制约．     

SYCY-86型实时处理瞬变光源颜色测定仪

介绍了SYCY-86型实时处理瞬变光源颜色测定仪的设计思想和工作原理.     

Compensatory caspase activation in MPP+-induced cell death in dopaminergic neurons

Many have hypothesized that cell death in Parkinsons disease is via apoptosis and, specifically, by the mitochondrial-mediated apoptotic pathway. We tested this hypothesis using a mouse dopaminergic cell line of mesencephalic origin, MN9D, challenged with the Parkinsonism-causing neurotoxin MPP⁺ (1-methyl-4-phenylpyridinium ion). Apoptosis was the main mode of cell death when the cells were subjected to MPP⁺ treatment under serum-free conditions for 24 h. Caspase-3 and caspase-9, however, were not activated, thus indicating the existence of alternate or compensatory cell death pathway(s) in dopaminergic neuronal cells. Using caspase inhibitors, we demonstrated that these pathways involve caspase-2, –8, –6 and –7. A time-course study indicated that activation of caspase-2 and –8 occurred upstream of caspase-6 and caspase-7. Upon MPP⁺ challenge, the apoptosis-inducing factor was translocated from the mitochondria into the MN9D cytosol and nucleus. These results suggest the existence of alternative apoptotic pathways in dopaminergic neurons.Received 20 September 2004; received after revision 5 November 2004; accepted 22 November 2004     

Functional and physical communication between oncoproteins and tumor suppressors

The discovery of oncogenes (c-onc’s) and tumor suppressors (TS’s) has led to the concept that cancer arises from defects in each of these classes of genes or their products. More recently, it has been appreciated that c-onc and TS proteins often affect one another’s functions. Within this context, I review the two classical TS’s, p53 and the retinoblastoma protein, and the consequences of their inactivation. The various forms of genomic instability (GI) that underly the high mutation rates of transformed cells are then discussed. Particular emphasis is placed upon the concept that GI is not only an integral part of the transformed state but is a prerequisite. Increased oxidative DNA damage, and/or an inabiliy to repair it, can lead to GI. The review then discusses recent observations showing that loss of the TS protein peroxiredoxin 1 (prdx1) and increased expression of the c-onc protein c-Myc, each leads to increased oxidative DNA damage. The critical nature of the c-onc-TS interaction is underscored by that occurring between prdx1 and c-Myc, with the former protein regulating the production of DNA-damaging reactive oxygen species by the latter. The intimate association between these proteins and others serves as a paradigm for the exquisite balancing act that c-onc’s and TS’s must maintain in order to properly control normal DNA replication and cellular proliferation while simultaneously minimizing the acquisition of potentially neoplastic mutations. Received 10 May 2005; received after revision 3 July 2005; accepted 19 July 2005     

丝网印刷中的环境污染问题与对策

随着社会经济的发展和人们环保意识的提高,我国对各行各业的环境保护法规将会越来越规范、健全。面对这一挑战。本文就丝网印刷行业中的主要污染泺进行了分析．并提出了相应的对策。