Synthesis and biological evaluation of new mono naphthalimide platinum(IV) derivatives as antitumor agents with dual DNA damage mechanism

Naphthalimide has emerged as an interesting DNA intercalator and possessed attracting antitumor properties. In this context, naphthalimide group was linked to platinum(IV) core to construct a series of new mono naphthalimide platinum(IV) derivatives. The title compounds exert effective antitumor activities to the tested tumor cells lines in vitro, especially the one with propionyl chain displays comparable or even better bioactivities than platinum(II) reference drugs cisplatin and oxaliplatin. Moreover, the mono naphthalimide platinum(IV) derivative displays comparable tumor growth inhibitory competence against CT26 xenograft tumors in BALB/c mice in vivo without severe toxic effects in contrast to oxaliplatin. A dual DNA damage mechanism was proven for the title complex. Both naphthalimide ligand and the liberated platinum(II) moiety could generate DNA lesions to tumor cells synergistically and active the apoptotic pathway by up-regulating the expression of caspase 9 and caspase 3. Meanwhile, the conversion of platinum(II) drug into tetravalent form by incorporating naphthalimide moiety increases the uptake of platinum in whole cells and DNA remarkably. All these facts might be the factors for the title platinum(IV) complexes to overcome platinum(II) drug resistance. Additionally, the mono naphthalimide platinum(IV) complex could interact with human serum albumin by hydrogen bond and van der Waals force which would further influence their storage, transport and bioactivities.     

A mesoporous non-precious metal boride system: synthesis of mesoporous cobalt boride by strictly controlled chemical reduction

Generating high surface area mesoporous transition metal boride is interesting because the incorporation of boron atoms generates lattice distortions that lead to the formation of amorphous metal boride with unique properties in catalysis. Here we report the first synthesis of mesoporous cobalt boron amorphous alloy colloidal particles using a soft template-directed assembly approach. Dual reducing agents are used to precisely control the chemical reduction process of mesoporous cobalt boron nanospheres. The Earth-abundance of cobalt boride combined with the high surface area and mesoporous nanoarchitecture enables solar-energy efficient photothermal conversion of CO₂ into CO compared to non-porous cobalt boron alloys and commercial cobalt catalysts.

Generating high surface area mesoporous transition metal boride is challenging but interesting because incorporation of boron atoms can generate lattice distortion to form amorphous metal boride which has unique properties in catalysis.     

二(三氟甲基磺酰)亚胺锂对磷酸铁锂正极高温行为的影响

系统研究了电解质锂盐对磷酸铁锂电极高温性能的影响, 并探讨了相关的作用机理. 差示扫描量热仪测试显示, 与LiPF₆相比, 二(三氟甲基磺酰)亚胺锂(LiTFSI)和LiBF₄具有对水份稳定且热稳定性好的优点, 更适合高温条件下使用. 应用等离子体发射光谱考察LiFePO₄在55 ℃和不同电解液体系中铁离子溶出程度, 结果表明, 在LiTFSI和无氟锂盐电解液中LiFePO₄的铁很少溶出, 而在LiPF₆电解液中却溶出严重, 且FePO₄的铁溶出量高于LiFePO₄. 循环伏安和光学显微镜测试结果显示少量LiBF₄的加入能有效抑制LiTFSI对集流体铝箔的腐蚀. 以LiTFSI和LiBF₄作为混合锂盐配成的电解液能显著改善LiFePO₄/Li电池的高温电化学性能, 在55 ℃和1 C倍率下循环40次后放电比容量达147.7 mAh/g.     

圆形重力式网箱锚碇系统的受力研究

依据Stokes二阶波浪理论和莫里森(Morison)方法,对圆形重力式网箱的浮架结构分别与工程上常用的两种锚碇系统(折线形与直线形)相结合情况下,锚碇系统的受力进行了数值计算及相应的物理模型试验。结果表明相同波况下折线形锚碇系统承受张力较小,在相同波浪周期条件下,波高越大锚碇点受力越大;相同波高下,锚碇点最大受力随周期变化不显著。将计算结果与模型试验对比,结果显示计算数值与试验数据较接近,表明了此计算方法的可行性,为进一步模拟浮架结构的运动变形打下基础。     

Structural responses of electrospun PVDF fibers induced by specific stretching and ensuing heating

Microstructure of electrospun fibers is often invoked to explain their properties but that is challenging to quantify properly. The electrospun PVDF fibers being rich in the β-phase crystal due to excellent piezoelectric properties are promising energy-harvesting materials for wearable and implantable applications. In this work, structural responses of electrospun PVDF fibers were investigated under the conditions of specific stretching at 25°C and ensuing heating from 25 to 170°C at strains of 5%, 10%, 20%, respectively, using the in situ WAXD with a thermos-mechanical coupled equipment. In this process, the fiber morphology, and the crystal orientation, the crystal structure, the β-phase content, as well as mechanical property of elctrospun PVDF fibers were studied. It is found that the specific stretching affects the β-phase crystal more than ensuing heating when the heating temperature is lower than the melting temperature of the fibers. Moreover, after 20% stretching and ensuing heating to 150°C, the tensile strength of electrospun PVDF fibers membrane can rise to 12.8 MPa, which is more than three times that of the pristine fibers, which is attributed to the higher crystal orientation and β-phase content, along with the alignment of the fibers. Therefore, structural responses of electrospun PVDF fibers induced by specific stretching and ensuing heating are propitious to explain and tailor their properties in practical applications, which also gives potential insights into other fibers.     

Wronskian and Grammian solutions for the (2+1)-dimensional BKP equation

The (2 + 1)-dimensional BKP equation in the Hirota bilinear form is studied during this work. Wronskian and Grammian techniques are applied to the construction of Wronskian and Grammian solutions of this equation, respectively. It is shown that these solutions can be expressed as not only Pfaffians but also Wronskians and Grammians.     

多孔硅拉曼光谱随激发功率变化的研究

用阳极氧化法新制备了多孔硅样品,以457．5nm固体激光器为激发光源,在不同激发功率下,获得了拉曼谱图和一些谱峰参量随激光功率的变化关系。解释了520cm^-1和300cm^-1附近拉曼峰随功率变化的一系列可逆的实验现象：随激光功率升高出现的红移和非对称性展宽,主要是由于样品局域平均粒径变小而受量子限域效应的影响导致的;样品局域平均粒径在表面上的二维减小与随激光功率升高而导致的局域温升并不违背基本的热力学定律;高功率时520cm^-1附近双峰的出现是由于多孔硅样品局域平均粒径达到一定阈值而导致的纵模和横模双声子模的分裂。     

Molecular assemblies based on the template-directing effect of anionic polyoxometalate clusters and organic cationic flexibility

Molecular assembly processes by utilizing the template-directing effect of anionic polyoxometalate clusters and the flexible organic cation have achieved three hybrids: (H₂bpp)(Hbpp)[PMo₁₂O₄₀]·3DMF (1), (H₂bpp)(Hbpp)(bpp)₂ [PMo₉V₃O₄₀(VO)₂]₂ (2), and (H₂bpp)₂[β-Mo₈O₂₆] (3) (bpp = 1,3-bis(4-pyridyl)propane). Three compounds were characterized using single crystal X-ray crystallography, elemental analysis, IR, XPS, EPR, voltammetric behavior and TGA. Crystal structural analyses revealed that compounds 1–3 were all constructed from protonated organic bpp cations with different POM clusters: isolated α-Keggin P–Mo cluster in 1; dimer of bi-capped α-Keggin P–Mo–V anions linked through a {V₂O₂} unit in 2; β-octamolybdate isopolyanion in 3, respectively. All three assemblies demonstrated a higher thermal stability. The protonated bpp cations lost at temperature higher than 300 °C that the strong intermolecular interactions may account for the high initial temperature of weight loss. The electrochemistry property of compound 2 modified carbon paste electrode was also studied in 1 M H₂SO₄ aqueous.     

聚酯类食品包装材料中二氧化钛在食品模拟物中的迁移规律

采用电感耦合等离子体质谱法(ICP–MS),在不同的模拟迁移条件(模拟物、盛放温度、接触时间、乙酸浓度、使用次数等)下,研究聚酯类食品包装材料中二氧化钛在6种食品模拟物(水、4%乙酸、10%乙醇、65%乙醇、正己烷和异辛烷)中的迁移规律。结果显示:食品模拟物的属性对迁移行为有显著影响,迁移量随温度的升高及时间的延长而增加,食品的酸性越强,二氧化钛的迁移量越大。因此需适量控制聚酯类食品包装材料的反复使用次数、盛放食品时的温度和时间以降低二氧化钛迁出风险。