EDXRF中几何探测光路分析及其优化设计

能量色散X射线荧光分析因其分析速度快、准确度高、分析过程简单等优势已经广泛的应用到医疗、考古等诸多领域。探测光路的最优化设计可以减小仪器散射本底,降低检出限,提高仪器的分辨率及探测效率,增强特征X射线的全能峰的峰背比,改善仪器的工作性能。应用自制的一款低检出限、高分辨率的能量色散X射线荧光分析仪,通过对纯元素Cu特征X射线探测完成了光谱仪几何光路最优化设计。实验结果表明,X射线管与样品的夹角、样品与探测器的夹角均为45°,X射线管到样品、样品到探测器的距离均为10mm时,特征X射线的峰背比最佳。同时将Al-Pb准直加装在光路中进行本底测量,散射本底以及仪器的检出限大大降低,提高了仪器的分辨率及探测效率,为痕量和微量元素的分析提供了优化的光路解决方案。     

MATLAB应用于离散时间系统分析的教学探讨

在离散时间系统分析的课堂教学中，借助科学计算软件MATLAB能在阐述概念的同时。避免过多的手动运算，即时给出相关结果和函数图形，使得在有限的时间内展现整个系统分析的流程，节省了时间，改善了授课效果．     

Inhibition of phosphodiesterase activity of human spermatozoa by spermine.

Sperm motility and metabolism are dependent upon the levels of cyclic AMP. Our studies have demonstrated that spermine by inhibiting sperm phosphodiesterase activity could regulate sperm physiology.     

标准红外辐射源的设计和制做方法

本文提出了一种利用红外辐射与吸收匹配原理,设计与制做标准红外辐射源的方法。实验表明用本文方法设计和制做的红外辐射源能够满足使用要求。     

加工番茄灌溉制度动态模拟研究

通过分析和提炼加工番茄水分需求的研究资料,在综合考虑气候条件、土壤理化性质、产量目标、品种特性等影响因子的基础上,根据水分平衡原理和水分需求规律、分阶段定量灌溉与加工番茄和环境影响因子之间的关系,建立了具有系统性和时空适用性的加工番茄灌溉制度动态知识模型。该模型可用于精确定量不同环境条件和产量目标下的水分需求总量及其在不同生育时期的分配比例。利用不同生态点、不同品种、不同土壤类型资料和不同产量目标等资料对水分运筹知识模型进行了验证,结果表明模型具有较好的决策性和适用性。     

Effect of nerve stimulation on rat skeletal muscle. A study of plasma membrane

Summary The gastrocnemius muscle of the rat showed no morphological, histometric or plasma membrane changes, after sciatic nerve stimulation with a 5 mA current for 30 to 60 min, 10 mA for 30 min and 15 mA for 5 min. However, 10 mA for 60 and 200 min gave rise to mitochondrial and plasma membrane abnormalities. These changes were absent after a rest period. The results indicated the sciatic nerve stimulation at 10 mA for 60 and 200 min caused reversible changes in the rat skeletal muscle mitochondria and plasma membrane.     

Delineation of prognostic biomarkers in prostate cancer

Prostate cancer is the most frequently diagnosed cancer in American men. Screening for prostate-specific antigen (PSA) has led to earlier detection of prostate cancer, but elevated serum PSA levels may be present in non-malignant conditions such as benign prostatic hyperlasia (BPH). Characterization of gene-expression profiles that molecularly distinguish prostatic neoplasms may identify genes involved in prostate carcinogenesis, elucidate clinical biomarkers, and lead to an improved classification of prostate cancer. Using microarrays of complementary DNA, we examined gene-expression profiles of more than 50 normal and neoplastic prostate specimens and three common prostate-cancer cell lines. Signature expression profiles of normal adjacent prostate (NAP), BPH, localized prostate cancer, and metastatic, hormone-refractory prostate cancer were determined. Here we establish many associations between genes and prostate cancer. We assessed two of these genes-hepsin, a transmembrane serine protease, and pim-1, a serine/threonine kinase-at the protein level using tissue microarrays consisting of over 700 clinically stratified prostate-cancer specimens. Expression of hepsin and pim-1 proteins was significantly correlated with measures of clinical outcome. Thus, the integration of cDNA microarray, high-density tissue microarray, and linked clinical and pathology data is a powerful approach to molecular profiling of human cancer.     

Large-scale discovery and genotyping of single-nucleotide polymorphisms in the mouse

Single-nucleotide polymorphisms (SNPs) have been the focus of much attention in human genetics because they are extremely abundant and well-suited for automated large-scale genotyping. Human SNPs, however, are less informative than other types of genetic markers (such as simple-sequence length polymorphisms or microsatellites) and thus more loci are required for mapping traits. SNPs offer similar advantages for experimental genetic organisms such as the mouse, but they entail no loss of informativeness because bi-allelic markers are fully informative in analysing crosses between inbred strains. Here we report a large-scale analysis of SNPs in the mouse genome. We characterized the rate of nucleotide polymorphism in eight mouse strains and identified a collection of 2,848 SNPs located in 1,755 sequence-tagged sites (STSs) using high-density oligonucleotide arrays. Three-quarters of these SNPs have been mapped on the mouse genome, providing a first-generation SNP map of the mouse. We have also developed a multiplex genotyping procedure by which a genome scan can be performed with only six genotyping reactions per animal.