Dimethyltin(IV) complexes derived from hydroxamic acid and acylhydrazone ligands: Synthesis,DNA/bovine serum albumin interaction and cytotoxicity

Two novel dimethyltin(IV) complexes, Me₂SnL¹(PyCOO)(MeOH) ( 1 ) and Me₂SnL² ( 2 ) (HL¹ = 4‐pyridinehydroxamic acid and H₂L² = 2‐hydroxy‐N′‐[(2‐hydroxy‐5‐chlorophenyl)methylidene]benzoylhydrazone), were synthesized and characterized using elemental analyses, Fourier transform infrared and NMR (¹H, ¹³C) spectroscopies and single‐crystal X‐ray diffraction. In complex 1 the geometry around the tin atom is a six‐coordinated distorted octahedral configuration, while complex 2 exhibits five‐coordinated distorted trigonal bipyramid geometry. Preliminary in vitro cytotoxicity studies with two human cancer cell lines (HeLa and A549) using MTT assay show that complex 1 is more potent than complex 2 . The interactions of the two complexes with calf thymus DNA and bovine serum albumin were also investigated using UV–visible absorption spectral, thermal denaturation and viscosity measurements and docking analysis. Investigations indicate that the structures of the mixed ligands play an important role in the properties of the dimethyltin(IV) complexes, and, to some extent, the antitumor activities of the complexes are partly related to interactions with DNA and some proteins in cancer cells.     

A universal method to calculate the surface energy density of spherical surfaces in crystals

Surface energy plays an important role in the mechanical performance of nanomaterials;however, deter-mining the surface energy density of curved surfaces remains a challenge. In this paper, we conduct atomic simulations to calculate the surface energy density of spherical surfaces in various crystalline metals. It is found that the average sur-face energy density of spherical surfaces remains almost constant once its radius exceeds 5 nm. Then, using a geomet-rical analysis and the scaling law, we develop an analytical approach to estimate the surface energy density of spherical surfaces through that of planar surfaces. The theoretical pre-diction agrees well with the direct atomic simulations, and thus provides a simple and general method to calculate the surface energy density in crystals.     

Synthesis and Characterization of La‐Doped Fe3O4‐Polyaniline Magnetic Response Nanocomposites

Lanathum (La)‐doped Fe₃O₄ magnetic nanoparticles were prepared in aqueous solution at room temperature, then La‐doped Fe₃O₄‐polyaniline (PANI) nanocomposites containing a dispersion of La‐doped Fe₃O₄ nanoparticles were synthesized via in‐situ polymerization of aniline monomer. The structure and properties of the synthesized samples were characterized with X‐ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectrometry (FTIR), thermogravimetric analysis (TGA), inductively coupled plasma atomic emission spectrometry (ICPAES), and a vibrating sample magnetometer (VSM). The resulting particles of La‐doped Fe₃O₄ and La‐doped Fe₃O₄‐PANI were almost spherical with diameters ranging from 15 to 25 nm and 25 to 85 nm, respectively. The La‐doped Fe₃O₄‐PANI composite presented core‐shell structures; polyaniline covered the La‐doped Fe₃O₄ completely. The specific saturation magnetization of La‐doped Fe₃O₄‐PANI depended on the starting material of La‐doped Fe₃O_4. It increased with increasing amounts of La and Fe₃O₄ content.     

对某废弃铀矿山辐射环境的调查分析

通过对我国某废弃铀矿山地表贯穿辐射剂量率2、22Rn析出率、空气中氡及其子体浓度、土壤和水体中天然放射性核素含量的监测,调查和分析了矿山辐射环境现状.结果表明,该废弃铀矿山已受到放射性污染.其中,1#矿点和尾矿堆放射性水平较高,是矿区主要放射性污染源项,应采取整治措施.其他区域放射性较低,未超过国家基本限值.     

混凝土硬化过程中的早期收缩裂缝分析

本文通过理论分析和工程实例,简要阐述了混凝土硬化过程中的早期收缩裂缝的产生原因、裂缝形态,混凝土浇筑过程中的注意事项,该类混凝土裂缝的一般处理方法,以供同行互相学习探讨.     

Molecular dynamics simulations of temperature effect on tungsten sputtering yields under helium bombardment

正Tungsten is the most promising plasma-facing material(PFM)for future nuclear fusion reactors such as international thermonuclear experimental reactor(ITER)owing to its high melting temperature,high thermal conductivity and low hydrogen retention[1].Under ITER-relevant conditions,a large amount of helium from the fusion reactions will constantly bombard the PFM.Though the energies of helium atoms in different regions are different,the flux and energy     

Difluoroboron β-diketonate dye with intense red/near-infrared fluorescence in solutions and solid states

Difluoroboron β-diketonate(BF_2 bdk) complexes have attracted much attention due to their outstanding photophysical properties.However,BF_2 bdk with near-infrared fluorescence usually suffer from emission quenching in solid state due to the π-π stacking in aggregation.Herein,we report a BF_2 bdk dye exhibiting donor-acceptor(D-A) structure with the difluoroboron moiety acting as the electron acceptor and the aminonaphthalene as the electron donor.It processes intense molar extinction coefficient,large Stokes shift and strong fluorescence in red/NIR region in both solution and aggregations.It was used for NIR imaging in living cells.     

甘肃省沥青路面水损坏调查分析

沥青路面水损坏是一种较为普遍的路面病害型式,通过对甘肃境内的几条高速公路调查,发现部分路段路面出现松散、坑槽等水损坏现象。按照沥青路面的早期水损坏发生的原因,可以将水损坏分为两类:自上而下的表面层水损坏和自下而上的水损坏。