一维链状镉(Ⅱ)配位聚合物{[Cd(PAc)2(4，4′-bipy)(H2O)]·4H2O}n的合成、晶体结构及热稳定性研究

A novel one-dimensional coordination polymer, {[Cd(PAc)₂(4,4-bipy)(H₂O)]·4H₂O}_n (HPAc=phenyl acetic acid, 4,4′-bipy=4,4′-bipyridine) was synthesized and characterized by element analysis, IR, TG and X-ray single diffraction crystal structure determination. It crystallizes in the monoclinic space group C2/c with a=2.088 5(4) nm, b=0.839 05(17) nm, c=1.683 5(3) nm, β=105.45(3)° and V=2.843 5(10) nm³, Z=4, M_r=628.94, F(000)=1 288, μ=0.820 mm^-1, R=0.019 9, wR=0.056 5. Each cadmium(Ⅱ) atom is seven-coordinated by four oxygen atoms from two different phenyl acetate groups and two nitrogen atoms from two 4,4′-pyridine ligands and one water molecule, forming a distorted pentagonal bipyramid coordination geometry. Adjacent cadmium(Ⅱ) atoms are bridged by 4,4′-pyridine ligand, constructing a infinite chain along the diagonal direction of ac plane. The Cd…Cd separation within the polymer is 1.164 6(4) nm. The three-dimensional supramolecular structures of the title complexes are constructed by hydrogen bonding interactions and π-π stacking interactions between the benzene rings of HPAc and 4,4′-bipy. CCDC: 616697.     

二维层状铜(Ⅱ)配位聚合物[Cu(PAc)2(μ-3-PyOH)2]n的合成、晶体结构及热稳定性研究

A two-dimensional coordination polymer, [Cu(PAc)₂(μ-3-PyOH)₂]_n(HPAc=phenyl acetic acid, 3-PyOH=3-hydroxypyridine) was synthesized and characterized by the element analysis, IR, TG and X-ray diffraction single crystal structure determination. The title complex crystallizes in the monoclinic system with space group P2₁/c, a=1.228 7(3) nm, b=0.967 05(19) nm, c=1.076 4(2) nm, β=109.93(3)° and V=1.202 4(5) nm³, Z=2, M_r=524.01, F(000)=542, μ=0.953 mm^-1, R=0.030 9, wR=0.080 7. Each copper(Ⅱ) ion displays an elongated octahedron with two nitrogen atoms from two different 3-PyOH ligands and two oxygen atoms from two different terminal phenyl acetate groups occupying the basal positions and two oxygen atoms of two different 3-PyOH ligands from the neighbouring molecules occupying the axial positions. Each four identical mononuclear Cu(Ⅱ) unit in the two-dimensional layer is joined by four 3-PyOH ligands, related by inversion centers with a Cu…Cu separation of 0.723 5(10) nm across the 3-PyOH-N,O bridge in bc plane. CCDC: 664483.     

医用钛表面TiO_2纳米管/HA复合膜层于Tyrode’s生理溶液中电化学腐蚀行为

钛及其合金具有良好的力学性能和生物相容性,被广泛地用作医用人工植入体.然而,钛植入体在人体内的生理环境中必然发生腐蚀,金属离子的溶出和积累可产生毒副作用.本文应用电化学方法对医用钛金属作表面改性,提高其生物活性,应用Tafel极化曲线和电化学阻抗(EIS)研究其耐蚀性能及腐蚀电化学行为.结果表明,在钛基TiO2纳米管阵列膜层上沉积构筑HA涂层之后,由于表面阻挡层的强化,TiO2涂层在Tyrode’s生理溶液中的耐蚀性有所提高.     

Fusarisetin A的合成研究进展

Fusarisetin A是一个结构新颖的tetramic acid类天然产物,它具有6-6-5-5-5并环骨架和10个手性中心.它对腺泡的形成以及细胞迁移和入侵有显著的抑制活性,表明此化合物具有选择性抑制肿瘤细胞转移的潜质.该综述总结了fusarisetin A自发现一年多时间来的合成进展情况.     

具有公共健康教育的随机潜蚤病模型动力学行为研究

潜蚤病是加勒比、拉丁美洲和撒哈拉以南的非洲等经济条件较差地区的一种常见的人畜共患病,其因发病率高,传染快受到人们的关注.而在这些经济贫困地区及时的公共健康教育是控制疾病的一种手段.基于此,本文研究了一类具有公共健康教育和饱和治疗率的随机潜蚤病模型的动力学行为.利用It?公式和构造Lyapunov函数等方法,首先证明了随机系统全局正解的存在唯一性;接着,分析了随机系统的正解围绕确定性系统的无病平衡点和地方病平衡点的渐近行为.最后,通过数值模拟验证了理论结果的正确性     

具有垂直传染和连续接种的甲肝传染病模型的研究

建立了具有垂直传染和两种时滞的甲肝传染病模型,通过构造Lyapunov函数分析了无病平衡点的全局吸引性和系统的持久性.最后,通过数值模拟验证比较了两种接种策略的优劣性.