Chromosomal localization of a unique gene by non-autoradiographic in situ hybridization

During the past few years, several methods have been developed for the detection of specific nucleic acid sequences by in situ hybridization using non-radioactive labels such as fluorochromes, cytochemically detectable enzymes and electron-dense markers. These methods are preferable to autoradiography in terms of speed of performance and topological resolution. Their limited sensitivity, however, has so far restricted their use to the detection of repeated sequences. Here we report single gene detection with a procedure using 2-acetylaminofluorene (AAF)-modified probes, immunoperoxidase cytochemistry and reflection-contrast microscopy. We confirmed the autoradiographic data on the localization of the human thyroglobulin (Tg) gene to the distal end of the long arm of chromosome 8. A mixture of cosmid cHT2-derived subclones of the 3' part of the Tg gene, 22.3 kilobase pairs (kbp) in total, was used as a hybridization probe. This procedure can be used to map other unique sequences, if genomic clones are available from which clones with an appropriate amount of inserts can be isolated.     

抛物型方程初值问题的概率数值解法

Ｆｒｉｅｄｍａｎ在［１］中给出了一般抛物型方程Ｃａｕｃｈｙ问题解的概率表达式。在此基础上，给出了它的概率数值及其误差估计。     

Acquired immunity and epidemiology of Schistosoma haematobium

Human immune responses to schistosome infection have been characterized in detail. But there has been controversy over the relative importance of ecological factors (variation in exposure to infection) and immunological factors (acquired immunity) in determining the relationships between levels of infection and age typically found in areas where infection is endemic. Independent effects of exposure and age on the rates of reinfection with Schistosoma haematobium after chemotherapy have been demonstrated in the Gambia and Zimbabwe. This age effect could be the result of acquired immunity to infection. Indeed, allowing for variation in exposure and age, low rates of reinfection in the Gambia are correlated with high amounts of specific IgE antibodies--human IgE can kill S. mansoni schistosomulae in vitro. Further, animals can acquire immunologically mediated resistance to S. mansoni infection, although nonimmunological factors could also be involved. Acquisition of this immunity seems to be related to the cumulative effects of repeated infection and provides only partial protection. These characteristics are consistent with immuno-epidemiological data for both S. mansoni and S. haematobium infections of humans. We have now analysed age-prevalence data for human infection with S. haematobium, and find patterns of variation that are indeed consistent with the epidemiological effects of acquired immunity predicted by mathematical models.     

一个临界情形的奇摄动拟线性二阶方程组的狄利克雷问题

研究了临界情形的拟线性二阶方程组的狄利克雷问题，证明了狄利克雷问题解的存在唯一性，并给出解的渐近展开式及余项，估计式．     

矩形管道层流流动近似计算

本文利用变分方法推出了矩形管道中完全发展段层流流动的速度,继而讨论了矩形管道中的流量、沿程阻力系数和压力损失等。实验结果表明,本文的分析是可靠的。     

浅析高校科研管理

本文从分析管理的重要性入手,提出了扭转和改进高校科研管理落后状况的途径。     

活塞环表面碳化铌镀覆新工艺试验研究

用化学液相沉积方法，在高强度灰铸铁活塞环表面实现了Ｎｂｃ覆层，盘销磨擦磨损试验表明，无论在无润滑的情况时，Ｎｂｃ镀层表面要比镀Ｃｒ表面或铸铁原始表面具有更高的耐磨性，可以延长活塞环使用寿命，而Ｎｂｃ镀层与铸铁之间低的磨擦系数可使Ｓ１９５柴油机磨擦损失降低０．３５ｋＷ，降低比油耗９－５ｇ／（ｋＷ．ｈ）。     

试论经济责任审计风险的控制

经济责任审计有其特殊性，它的对象不是单位，而是人。针对经济责任审计风险成因的特殊性，提出了控制经济责任审计风险的防范措施。     

基于像素特征的路面裂缝图像自适应滤噪

分析了破损路面图像的像素点区域特征，针对不同区域提出加权邻域滤波和自适加权中值滤波算法。其权值是通过对图像中区域特征的推理得到的，所以算法中能根据图像的区域特征自适应的进行滤波。试验表明，本算法能够有效滤除噪声，并具有很好的细节保护能力。