白藜芦醇磺酸酯的合成及抗氧化、抗肿瘤活性的研究

以白藜芦醇和2, 4-二硝基苯磺酰氯为原料,通过酯化法得到白藜芦醇磺酸酯,通过NMR和LC-MS确定了该化合物结构。以维生素C为阳性对照,研究白藜芦醇磺酸酯对2, 2-联苯基-1-苦基肼(DPPH)自由基和2, 2′-联氮-双-3-乙基苯并噻唑啉-6-磺酸(ABTS)自由基的清除活性和抗氧化活性;噻唑蓝(MTT)法研究其对人肺癌细胞A549的增殖活性。实验结果表明,目标产物收率为33.1%。同时,目标产物在浓度为1.0 mg/mL时,对DPPH自由基和ABTS自由基的清除率分别为31.6%和42.7%,抗氧化活性均高于白藜芦醇,但低于维生素C;目标产物对人肺癌细胞A549具有较好抑制作用,IC50值为(10.2±0.37)μg/mL。     

Methionine restriction up‐regulates the expression of the pi class of glutathione S‐transferase partially via the extracellular signal‐regulated kinase‐activator protein‐1 signaling pathway initiated by glutathione depletion

Understanding the molecular events underlying gene regulation by amino acids has attracted increasing attention. Here, we explored whether the mechanism by which methionine restriction affects the expression of the π class of glutathione S‐transferase (GSTP) is related to oxidative stress initiated by glutathione (GSH) depletion. Rat primary hepatocytes were cultured in an L‐15‐based medium in the absence or presence of 200 μM L ‐buthionine sulfoximine (BSO) or in a methionine‐restricted L‐15 medium supplemented with 20 μM L ‐methionine up to 72 h. BSO and methionine restriction time‐dependently induced GSTP mRNA and protein expression in a similar pattern accompanied by a decrease in the cellular GSH level. The phosphorylation of extracellular signal‐regulated kinase (ERK), but not of c‐Jun NH₂‐terminal kinase and p38, was stimulated by methionine restriction and BSO. Electromobility gel shift assay showed that the DNA‐binding activity of nuclear activator protein‐1 (AP‐1) increased in cells exposed to methionine restriction or BSO. With the ERK inhibitor FR180204, AP‐1 activation and GSTP expression were abolished. Moreover, the induction of GSTP by methionine restriction and BSO was reversed by GSH monoethyl ester and N‐acetylcysteine. Our results suggest that methionine restriction up‐regulates GSTP gene expression, which appears to be initiated by the ERK‐AP‐1 signaling pathway through GSH depletion in rat hepatocytes.     

A Novel Mixed-Valence Tetranuclear Iron-Oxygen Clusters in the Organically Templated Iron Phosphate [H3N(CH2)2NH3]2 Fe4O(PO4)4 ċH2O

A novel iron phosphate templated with ethylenediammonium cation, [H₃N(CH₂)₂NH₃]₂ Fe₄ O(PO₄)₄H₂O, has been synthesized hydrothermally and characterized by single-crystal X-ray diffraction, thermo-gravimetric analysis, magnetic susceptibility and Mossbauer spectroscopy. The compound crystallizes in the mono-clinic space group C2 with a= 30.3801(5),b= 10.1204(5),c= 10.0977(5) Å, = 107.712(1)°, V = 2957.5(4) ų and Z = 6. The structure contains 5 and 6-coordinated Fe atoms bridged by ₄-oxygen and PO₄ groups to form two types of mixed-valence Fe₄P₄ cubane-like clusters, which are connected via Fe- O- P bonds to give rise to intersecting channels that house the ethylenediammonium cations and water molecules. Room-temperature Mossbauer data confirm the presence of Fe^II and Fe^III.     

我国萤石矿产资源可持续开发利用研究

我国的萤石矿产资源丰富，但由于萤石资源分布比较集中，矿床的品位低，加上缺乏统一的规划管理，资源浪费严重，且出口量过大。在分析我国萤石资源优势和开发利用中存在问题的基础上，提出了实施和完善战略性矿产资源储备制度以保护资源；加强地质勘察力度以增加储量；充分利用尾矿和贫矿资源；寻找和使用接替资源等措施。     

一体化智能抢修指挥系统在电网调度中的应用

介绍了一体化智能抢修指挥系统（TCM）的内涵,在分析TCM的技术亮点的基础上,解析了TCM在浦东电网调度工作中的应用案例,阐述了将TCM结合智能电表及用电信息采集系统、配电自动化系统建设的应用前景,用以优化电网故障处理流程,提高电网故障响应能力,提升对客户的服务水平.分析认为：TCM取得了创新性的实用化科研成果,对电网运行过程中出现的各种故障信息能够自动接入并提示,辅助热线支持组人员通过故障登记、工单合并,提高了工作效率和故障抢修速度,在优化抢修资源后进一步提高了供电可靠性,实现了电网与客户的互动服务,具有推广应用价值.     

Investigation of substrate bias effects on the reactively sputtered ZrN diffusion barrier films

ZrN diffusion barrier films were prepared by DC reactive magnetron sputtering under different negative substrate bias. The composition, microstructure, resistivity and diffusion barrier properties of ZrN films, with respect to substrate bias, were studied by means of X-ray diffraction, electron probe microanalyzer, Auger electron spectroscopy, and four point probe method. Results showed that the deposition rate and impurity oxygen content of ZrN films were substantially influenced by the resputtering effects due to the ion bombardment on the film surface. The competition between surface energy and strain energy made the preferred orientation of ZrN films change from (1 1 1) to (2 0 0) and then back to highly (1 1 1) preferred orientation as a function of substrate bias. The application of negative substrate bias could effectively decrease the electrical resistivity due to the decrease of impurity oxygen content and the densification of films, resulting from the moderate-energy ion irradiation. The biased ZrN films could successfully be used as a diffusion barrier layer, between Cu and SiO₂, even up to the high temperature of 800 °C for 30 min.     

Wide-band guided-wave acoustooptic Bragg cells in GaAs-GaAlAs waveguide

One of the key components in future GaAs-based monolithic integrated acoustooptic modules or circuits is an efficient and wide-band acoustooptic Bragg cell. In this paper, design, fabrication, and performance characteristics of compact miniaturized GaAs-GaAlAs waveguide acoustooptic Bragg cells that operate at the acoustic frequency from 190 to 625 MHz are reported. A 201 MHz bandwidth has been obtained with the Bragg cell that employs a single tilted-finger chirp transducer centering at 360 MHz. The acoustic propagation losses in the GaAs-GaAlAs waveguides that were measured using acoustooptic Bragg diffraction as a probe are also presented.     

利用L1范数求取道间时差技术进行地震道插值

本文采用L1范数求取道间时差技术求出剖面上每一样点的时间倾角，然后逐道进行倾角插值。当出现较多空道时，利用L1范数极小准则找出差值道集中绝对值最小点对应的移动时间，求出时间倾角进行插值。此法既能适应线性同相轴插值、非线性同相轴插值，又能适应等道距、非等道距插值。通过对合成记录及实际记录的处理表明，此法具有比常规道内插方法速度快、精度高、适应性强等优点。     

Experimental 0.1 μm p-channel MOSFET withp+-polysilicon gate on 35 Å gate oxide

Very-high-transconductance 0.1 μm surface-channel pMOSFET devices are fabricated with p⁺-poly gate on 35 Å-thick gate oxide. A 600 Å-deep p⁺ source-drain extension is used with self-aligned TiSi₂ to achieve low series resistance. The saturation transconductances, 400 mS/mm at 300 K and 500 mS/mm at 77 K, are the highest reported to date for pMOSFET devices     

Gelation Kinetics of Agars from Pterocladia capillacea Examined by Dynamic Rheometry

ABSTRACT: The changes in storage modulus (G') during isothermal gelation of agar fractions from Pterocladia capillacea were kinetically investigated with respect to the curing condition, agar concentration, and the molecular property of agar. Generally, the reciprocal of gelling time, the maximal increasing rate of G', and the rate constants of Avramipseudo-1st-order kinetics correlated with the curing conditions more significantly than with the molecular properties examined. This tendency was opposite to the result based on simple 2nd-order rate constant. And, the effects of molecular size on rheological and kinetic parameters were greater than those of the 3,6-anhydro-galac-tose content examined. After verification of the kinetic data obtained, potentially molecular changes during gelation process are illustrated.