The DNA content of mouse two-cell embryos can be measured by microfluorimetric image analysis under conditions of cell viability

Video-enhanced fluorescence imaging was used to quantify the DNA content in live two-cell mouse embryos. DNA was stained with the vital fluorophore Hoechst 33342. Conditions of dye concentration and irradiation were such that two-cell embryos could be kept in the constant presence of the dye for about 24 h without a major effect on their furtherin vitro viability. Total nuclear fluorescence intensity of stained two-cell embryos was measured twice under these conditions, i.e., in G1 (1 h after cleavage) and in G2 (15–18 h after cleavage), by image analysis. After correcting for the fluctuations in excitation intensity and for the spatial nonhomogeneities of the optical system (lenses and sensor), the mean total nuclear fluorescence intensity was about twofold higher in G2 than in G1 (R=1.99 to 2.25), and this increase was abolished by the addition of aphidicolin, an inhibitor of replication. The fluorescence increase did not depend on the Hoechst concentration in the range of 10–40 ng/ml, i.e., in the range of embryo viability. The coefficient of variation of the total nuclear fluorescence intensity measured under these conditions was rather large (10 to 20%). Nevertheless, the mean value of fluorescence intensity in G1 of nuclei of a given pool represents an appropriate reference to measure the increase in fluorescence intensity between G1 and G2.     

建立北京市工业经济宏观监测预警评价体系

本文系统介绍了北京市统计应用研究所、北京市经济学院、中料院应用数学研究所于１９９２年协作研究并建立的北京市Ｌ业经济宏观监测预警评价体系,给出了总系统和三个子系统的设计思想、方法与结果,并对１９９２年下半年及１９９３年北京市工业经济形势提供了预测判断与政策模拟分析．     

安全性评估方法在通用飞机航电系统中的应用

目前国内通用飞机产业发展进入加速期,对于国内飞机厂商及供应商而言,如何研制出满足适航安全性要求的产品以取得适航许可成为最为迫切的问题之一。以自行研制的多发涡轮通用飞机航电系统为例,给出了一种在系统架构设计中运用安全性评估并利用评估结果对系统架构提出改进措施的方法。对灾难级失效状态的分析结果表明,合理利用安全性评估方法能够有效地找出设计过程中存在的缺陷和风险以满足适航安全性要求。     

EWR早期截获能力指标及其计算方法

针对弹道导弹远程预警雷达(EWR)的早期截获能力计算难题,从反导预警效能生成的视角论证选取了截获高度与探测资源占用率两个早期截获能力评估核心指标,提出了文中两个指标在有/无引导条件的计算模型和方法,并进行了实例演算。计算结果表明:文中提出的指标及计算方法能有效地表征EWR 在既定作战场景中的早期截获能力,可为EWR与反导预警系统的战前任务筹划和战中实施调整提供快速计算支持。     

Network security threat warning method based on qualitative differential game

Most current network security research based on game theory adopts the static game or multi-stage dynamic game model,which does not accord with the real-time change and continuity of the actual network attack-defense process.To make security threats warning more consistent with the attack-defense process,the threat propagation process was analyzed referring to the epidemic model.Then the network attack-defense game model was constructed based on the qualitative differential game theory,by which the evolution of the network security state could be predicted.Based on the model,the qualitative differential game solution method was designed to construct the attack-defense barrier and divide the capture area.Furthermore,the threat severity in different security states were evaluated by introducing multidimensional Euclidean distance.By designing the warning algorithm,the dynamic warning of the network security threat was realized,which had better accuracy and timeliness.Finally,simulation results verify the effectiveness of the proposed algorithm and model.     

基于机动特征辅助的MFR状态预测方法

针对多功能雷达（Multi-Function Radar,MFR）状态预测方法存在的鲁棒性、预测正确率不佳的问题,提出一种基于机动特征辅助的MFR状态预测方法.该方法将载机机动信息与常规侦收参数共同作为预测特征集,一方面利用支持向量回归（Support Vector Regression,SVR）和侦收信号特征集,得到常规预测模型,另一方面通过SVR和机动特征集,得到MFR各个状态间的转变概率模型;然后利用D-S证据理论得到最终预测状态.实验结果表明,与SVR和LSR方法相比,平均预测精度分别提高了6.97%和7.2%,同时具备更优异的鲁棒性.此外,提出的预测方法通过进一步的拓展,可应用于机械设备、道路交通等领域.     

Platelet–Leukocyte Hybrid Membrane‐Coated Immunomagnetic Beads for Highly Efficient and Highly Specific Isolation of Circulating Tumor Cells

Biomimetic cell‐membrane‐camouflaged nanoparticles with desirable features have been widely used for various biomedical applications. However, the current research focuses on single cell membrane coating and using multiple cell membranes for nanoparticle functionalization is still challenging. In this work, platelet (PLT) and leukocyte (WBC) membranes are fused, PLT–WBC hybrid membranes are coated onto magnetic beads, and then their surface is modified with specific antibodies. The resulting PLT–WBC hybrid membrane‐coated immunomagnetic beads (HM‐IMBs) inherit enhanced cancer cell binding ability from PLTs and reduce homologous WBC interaction from WBCs, and are further used for highly efficient and highly specific isolation of circulating tumor cells (CTCs). By using spiked blood samples, it is found that, compared with commercial IMBs, the cell separation efficiency of HM‐IMBs is improved to 91.77% from 66.68% and the cell purity is improved to 96.98% from 66.53%. Furthermore, by using the HM‐IMBs, highly pure CTCs are successfully identified in 19 out of 20 clinical blood samples collected from breast cancer patients. Finally, the robustness of HM‐IMBs is verified in downstream CTC analysis such as the detection of PIK3CA gene mutations. It is anticipated that this novel hybrid membrane coating strategy will open new possibilities for overcoming the limitations of current theranostic platforms.     

天空双基地预警雷达空间同步效果优化

天空双基地预警雷达空间同步效果评估与优化是其空间同步技术的重要一环。首先,提出了空间同步效果的评估指标,分析其三大影响因素;其次,针对每个波位需要的波束驻留时间不同的问题,提出了脉冲积累优化方案,对其工作流程和相关参数计算进行推导;然后,从对波位编排灵活控制的角度提出了波位编排优化方案;最后,设计仿真实验对两种同步效果优化方案进行验证。仿真结果表明：两种优化方案可以使得接收信噪比和空间覆盖率的空间分布更加均匀,提高了发射能量的利用效率,有助于空间同步效果的优化。