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．     

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     

有偿债基金机制的公司债定价模型

有偿债基金的公司债是发行公司专门提取偿债基金以保证本息偿还的公司债券,它具有提前偿还的性质.由于计提偿债基金会引起公司资产的跳跃,给出了公司在计提偿债基金前没有违约的概率以及在此条件下公司资产的条件分布,并利用首次通过模型得到债券定价公式,通过数值计算作图分析了债券价格随参数变化的金融意义.     

中立型抽象微分方程Sp-权伪概周期弱解的存在性

 利用中立型微分方程S^p-权伪概周期函数的一个新分解定理和Krasnoselskii’s不动点定理,得到了中立型抽象微分方程的S^p-权伪概周期弱解存在性条件.     

海南省汉族人头面部测量指标与指数值的年龄变化

 在海南琼海市和万宁市的城市和乡村调查了汉族643例(男为334例,女为309例)成人的22项头面部体质指标,计算了13项头面部体质指数,对海南汉族头面部形态特征的年龄变化进行了初步分析.结果显示:① 眼内角间宽、眼外角间宽、唇高、红唇厚度这4项指标值与年龄呈负相关.上唇皮肤部高度、容貌耳长、容貌耳宽、面颊皮褶这4项指标值与年龄呈正相关.并且上述指标值在不同年龄组中存在有统计学意义的差异.② 随年龄增长,口指数值下降,并且在不同年龄组中存在有统计学意义的差异.海南汉族人头面部测量指标与指数值随年龄增长呈现一定的变化规律.     

Banach空间中相对非扩张映射的强收敛定理

用修正后的Halpern's迭代方法在Banach空间建立了一个迭代序列,证明了这一迭代序列强收敛到2个相对非扩张映射的公共不动点.