含三氟甲基和双希夫碱化合物的合成与表征

利用1,4-双(4-氨基-2-三氟甲基苯氧基)苯与苯甲醛或其衍生物的反应,合成了一系列含三氟甲基和双希夫碱的新化合物,其结构经UV,1HNMR,IR和元素分析表征。     

Dual mechanisms of Bcl-2 regulation in IP3-receptor-mediated Ca2+ release: A computational study

Inositol 1,4,5-trisphosphate receptors (IP₃R)-mediated calcium ion (Ca²⁺) release plays a central role in the regulation of cell survival and death. Bcl-2 limits the Ca²⁺ release function of the IP₃R through a direct or indirect mechanism. However, the two mechanisms are overwhelmingly complex and not completely understood. Here, we convert the mechanisms into a set of ordinary differential equations. We firstly simulate the time evolution of Ca²⁺ concentration under two different levels of Bcl-2 for the direct and indirect mechanism models and compare them with experimental results available in the literature. Secondly, we employ one- and two-parameter bifurcation analysis to demonstrate that Bcl-2 can suppress Ca²⁺ signal from a global point of view both in the direct and indirect mechanism models. We then use mathematical analysis to clarify that the indirect mechanism is more efficient than the direct mechanism in repressing Ca²⁺ signal. Lastly, we predict that the two mechanisms restrict Ca²⁺ signal synergistically. Together, our study provides theoretical insights into Bcl-2 regulation in IP₃R-mediated Ca²⁺ release, which may be instrumental for the successful development of therapies to target Bcl-2 for cancer treatment.     

基于改进迭代阈值的白细胞图像分割方法

人体外周血五类白细胞数量和所占比例反映了人体的健康状态,人工检查白细胞消耗医务人员的大量精力,如何用智能方法快速、准确进行白细胞智能分类是一个亟待解决的问题,其中白细胞分割的准确性是正确分类的关键。提出了一种改进的迭代阈值图像分割算法,对恢复有丝分裂连线的最小距离方法进行了基于数学和数模分析的预处理改良,提升了白细胞图像分割的精度和效率,解决了血小板粘连、白细胞边界不分明等问题。将白细胞从复杂的血液环境中分离出来,对有丝分裂细胞的多叶核进行最小距离判定并连线,然后定位到每个白细胞,制作数据集,最后用CNN分类。经测试,分割正确率达到了96%以上。实验结果验证了所提分割方法的准确性、高效性和实用性。     

微分求积法求解悬臂L梁固有振动特性研究北大核心CSCD

悬臂L梁结构由于具有柔性大、可设计性强、空间利用充分,振动过程中变形方式多样等独特优势而受到了广泛的关注与研究.该文提出了一种基于微分求积法求解末端附加质量块的矩形等截面均质悬臂细长L梁的各阶固有频率和模态的方法.在双坐标系下,基于Euler-Bernoulli梁理论建立了悬臂L梁的动力学方程,然后通过选取Chebyshev多项式的根作为节点坐标、选取Lagrange插值基函数、求解各阶权系数、处理边界条件等步骤,最终利用求解矩阵广义特征值问题的方法求得结构各阶固有频率及模态.在边界条件的处理上,直接将边界条件施加于边界点上,通过对比研究验证了该文固有频率理论解的正确性.最后分析了末端质量、内外梁的长度比、宽度、厚度对各阶固有振动特性的影响.该方法可以进一步应用推广到相关结构振动的研究中.