The excitation energies and term energies of the excited states 1s2ns (n=3,4,5) and 1s2nf (n=4,5) of lithium-like systems of Z=11－20

In this paper, the full-core plus correlation (FCPC) and the Ritz method is extended to calculate the non-relativistic energies of 1s^2ns (n=3,4,5) and 1s^2nf (n=4,5) states and the wavefunctions of the lithium-like systems from Z=11－20. The mass-polarization and the relativistic correction including the kinetic-energy correction, the Darwin term, the electron－electron contact term, and the orbit－orbit interaction are evaluated perturbatively as the first-order correction. The contribution from quantum electrodynamic is also included by using the effective nuclear charge formula. The excited energies, the term-energy and fine structure, are given and compared with the other theoretical calculation and experimental results. It is shown that the correlative wave in the FCPC method embodies well the strong correlation between the 1s^2 core and the valence electron.     

Colorimetric enantiodiscrimination of mandelic acid by indicator displacement assay

The colorimetric enantiodiscrimination between mandelic acid and L-proline-Cu(II) is exploited to develop enantioselective indicator displacement assays. The sensitivity of the assay could be tuned by using a colorimetric indicator. The chromophoric ligand, pyrocatechol violet, effectively competes with the mandelic acid guest for open coordination sites on L-proline-Cu(II). The DA could be increased to 0.12 by changing the ratio of(+)- and(à)-mandelic acid concentrations that were found to be optimal from the displacement experiments. The resultant enantiomer excess versus DA relationship is linear. From the calibration curves, the absorbance values of the unknowns may be calculated for the enantiomeric excess value and the colorimetric enantiodiscrimination of mandelic acid can thus be obtained.     

化学双语教学微型课程“能量转化”的实践

化学双语教学微型课程"能量转化",在高中必修教材基础上对知识进行拓展,分析了化学反应中3种能量转化形式即化学能与光能、热能、电能的转化。内容包括介绍荧光棒的成分和作用原理;学习粗测饼干所含热量的方法,并分析误差原因;了解冷敷创可贴的应用,体会化学原理与实际生产、生活的联系;通过可乐电池的学生实验,进一步认识燃料电池。化学双语教学微型课程"能量转化"分2课时完成,教学实践包括教学目标的确定、教材的编写、2个阶段的教学过程以及实施教学评价等。     

Porous metal membranes for solid-phase extraction of polycyclic aromatic hydrocarbons

Solid-phase extraction (SPE) is one of the most important techniques for sample preparation, purification, concentration and cleanup. Membranes made from synthetic organic polymers, cellulose, or glass fibers are used for sample pretreatment. In this work, we report that a porous metal membrane, the metal filter in HPLC, was used as a novel kind of solid-phase extraction adsorbent material. To evaluate the performance of the porous metal membrane for the SPE, naphthalene, fluorene, anthracene, phenanthrene, fluoranthene, pyrene, chrysene, perylene and benzo(a)pyrene were selected as analytes. Several parameters that affected the extraction efficiency such as the extraction time, the concentration of NaCl, the extraction temperature and the agitation speed were optimized. The experimental result indicates that the porous metal membrane possesses high adsorption ability to the tested polycyclic aromatic hydrocarbons (PAHs). Under the optimum conditions, the detection limits of the developed method were in the range of 0.03-0.082 μg L(-1) (S/N = 5), and excellent linear correlations between peak area and concentration of PAHs were found over the range of 0.1-60 μg L(-1). The precisions (RSD) for five replicate extractions of the PAHs from sample solutions were in the range of 2.6-5.0%. The recoveries of the PAHs from tap water and river water samples spiked with 9 PAHs (20 μg L(-1) of each individual PAH) ranged from 83.0% to 112.5%. The porous metal membrane is durable, simple, inexpensive, reproducible and has a high adsorption ability for use in SPE of PAHs.     

A priori estimate for non-uniform elliptic equations

A priori estimate for non-uniform elliptic equations with periodic boundary conditions is concerned. The domain considered consists of two sub-regions, a connected high permeability region and a disconnected matrix block region with low permeability. Let ? denote the size ratio of one matrix block to the whole domain. It is shown that in the connected high permeability sub-region, the Hölder and the Lipschitz estimates of the non-uniform elliptic solutions are bounded uniformly in ?. But Hölder gradient estimate and Lp estimate of the second order derivatives of the solutions in general are not bounded uniformly in ?.     

多壁碳纳米管诱导A549细胞氧化应激与去极化线粒体膜电位

以人肺上皮细胞系A549为模型细胞, 探讨多壁碳纳米管的细胞毒性效应及其机制. A549细胞暴露于不同浓度(0~300 μg/mL)的多壁碳纳米管后, 用MTT比色法检测细胞活力和Hoechst 33342染色法观察细胞形态; 用活性氧(ROS)敏感探针2',7'-二氯荧光素二乙酸酯(DCFH-DA)结合流式细胞仪检测细胞内ROS水平; 用荧光探针JC-1结合激光共聚焦显微镜检测细胞线粒体膜电位ΔΨm的变化; 用免疫荧光和蛋白印迹法检测细胞氧化应激敏感蛋白血红素氧合酶-1(HO-1)的表达水平. 结果表明, 多壁碳纳米管可引起A549细胞活性降低、细胞内活性氧ROS过量产生以及谷胱甘肽GSH含量下降, 诱导细胞氧化应激效应; 抗氧化剂N-乙酰半胱氨酸(NAC)抑制多壁碳纳米管诱导的A549细胞内ROS的产生. 多壁碳纳米管处理A549细胞2 h后, 诱发细胞线粒体膜电位下降; 多壁碳纳米管诱导细胞氧化应激的同时伴有适应性应激蛋白HO-1的上调表达. 结果表明, 细胞氧化应激和线粒体膜电位去极化可能是多壁碳纳米管诱导A549细胞毒性效应的重要机制.     

Thermosetting resins from a tetra-functional vinylbenzene compound possessing cyclic siloxane cores

Cyclic siloxane is an attractive building block for incorporation of silicon-containing units as well as their distinguished properties to polymer materials. This work reports the synthesis and characterization of a tetra-functional vinylbenzene compound possessing cyclic siloxane cores (cD₄-4VB). Synthesis of cD₄-4VB is carried out using cD₄-4SiH as the reactive precursor and multiple-step reactions, including hydrosilylation, deacetylation, and S_N2 substitution. cD₄-4VB is an effective monomer for preparation of the corresponding cyclic silicon-based thermosetting resins (CR-cD₄-4VB). CR-cD₄-4VB shows attractive film formability and good thermo-mechanical properties, including a storage modulus of 2.0 GPa, a glass transition temperature of 282°C, a thermal stability above 400°C, a high char yield (at 800°C in nitrogen) of 55 wt%, and a dielectric constant of 3.12 at 10 GHz. This kind of resins have potential of application for halogen-free flame retardants and high-performance polymer films.     

Simultaneous treatment with sorafenib and glucose restriction inhibits hepatocellular carcinoma in vitro and in vivo by impairing SIAH1-mediated mitophagy

Transarterial chemoembolization (TACE) is the first-line treatment for unresectable intermediate-stage hepatocellular carcinoma (HCC). It is of high clinical significance to explore the synergistic effect of TACE with antiangiogenic inhibitors and the molecular mechanisms involved. This study determined that glucose, but not other analyzed nutrients, offered significant protection against cell death induced by sorafenib, as indicated by glucose deprivation sensitizing cells to sorafenib-induced cell death. Next, this synergistic effect was found to be specific to sorafenib, not to lenvatinib or the chemotherapeutic drugs cisplatin and doxorubicin. Mechanistically, sorafenib-induced mitophagy, as indicated by PINK1 accumulation, increased the phospho-poly-ubiquitination modification, accelerated mitochondrial membrane protein and mitochondrial DNA degradation, and increased the amount of mitochondrion-localized mKeima-Red engulfed by lysosomes. Among several E3 ubiquitin ligases tested, SIAH1 was found to be essential for inducing mitophagy; that is, SIAH1 silencing markedly repressed mitophagy and sensitized cells to sorafenib-induced death. Notably, the combined treatment of glucose restriction and sorafenib abolished ATP generation and mitophagy, which led to a high cell death rate. Oligomycin and antimycin, inhibitors of electron transport chain complexes, mimicked the synergistic effect of sorafenib with glucose restriction to promote cell death mediated via mitophagy inhibition. Finally, inhibition of the glucose transporter by canagliflozin (a clinically available drug used for type-II diabetes) effectively synergized with sorafenib to induce HCC cell death in vitro and to inhibit xenograft tumor growth in vivo. This study demonstrates that simultaneous treatment with sorafenib and glucose restriction is an effective approach to treat HCC, suggesting a promising combination strategy such as transarterial sorafenib-embolization (TASE) for the treatment of unresectable HCC.Subject terms: Liver cancer, Mitophagy, Apoptosis     

基于椭圆型方程的扭叶片造型方法的研究

本文以偏微分方程造型为基础,提出了一种基于椭圆型方程的扭叶片三维型面直接设计方法,详细推导了叶型曲面函数,给出了型面方程的求解及其前后缘修正。该方法具有设计叶型曲面自然光顺,设计参数少且各参数具有明显的几何意义,叶型曲面调整方便,利于采用非数值优化算法对其进行气动优化等优点。文中给出了设计实例,并通过数值实验分析了所设计叶片型面的流动特性。分析结果表明设计叶片具有良好的气动性能,同时也证明了本文提出的基于椭圆型方程的扭叶片三维型面设计方法的可靠性和实用性。     

Studies on the Constituents of the Root-Bark of Hernandia Ovigera L. (III)

In the course of continuing search for the constituents of the root-bark of Hemandiu ovigera L., led to the isolation of eight compounds: desoxypodophyllotoxin(I), thalicarpine(III)) dehydrothalicarpine(IV), ovigerine(V), hernangerine(VI), hernandonine(VIII) and two unknown substances, mp. 219–220° and mp. 269–270°. Desoxypodophyllotoxin( I) and thalicarpine(III) exhibited a distinctively cytotoxic activity against nasopharynx carcinoma was reported by S. M. Kupchan et.al^3,9. Dehydrothalicarpine( IV) is merely a dehydro product of thalicarpine(III) at C–6a and C–7 of aporphine moiety. The isolation of dehydrothalicarpine(IV) made the first instance from Hernandia ovigera L. Comparison of their components distribution in each part of Hernandia ovigera was shown in Table I.