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关键词： adhesion   HDM2   migration   p53   SOX2   wound healing  

摘要： The altered expression of the SOX2 transcription factor is associated with oncogenic or tumor suppressor functions in human cancers. This factor regulates the migration and invasion of different cancer cells. In this study we investigated the effect of constitutive SOX2 overexpression on the migration and adhesion capacity of embryonal teratocarcinoma NT2/D1 cells derived from a metastasis of a human testicular germ cell tumor. We detected that increased SOX2 expression changed the speed, mode and path of cell migration, but not the adhesion ability of NT2/D1 cells. Additionally, we demonstrated that SOX2 overexpression increased the expression of the tumor suppressor protein p53 and the HDM2 oncogene. Our results contribute to the better understanding of the effect of SOX2 on the behavior of tumor cells originating from a human testicular germ cell tumor. Considering that NT2/D1 cells resemble cancer stem cells in many features, our results could contribute to the elucidation of the role of SOX2 in cancer stem cells behavior and the process of metastasis.

关键词： Cr (VI)   ion exchange   isotherms   kinetics   desorption  

摘要： The adsorption of Cr (VI) by an anion exchange resin of DEX-Cr, which contains tertiary and quaternary amine groups, was studied under varying experimental conditions that include pH, resin amount, contact time, and temperature. Batch-shaking experiments were conducted to evaluate the performance of DEX-Cr in removing Cr (VI). The ion-exchange process indicated that the maximum removal could be achieved at pH of 3 and an initial Cr (VI) concentration of 2200 mg/L. The results of adsorption equilibrium experiments fit well with Freundlich isotherm, showing that the adsorption was a multilayer process. Thermodynamic parameters indicated that the uptake of Cr (VI) by DEX-Cr was spontaneous and endothermic. Kinetic experimental data followed the pseudo first-order equation. The desorption study revealed that adding NaCl to NaOH solution helped to improve elution efficiency dramatically. The elution results had a relationship with the mass fraction of NaCl to NaOH, higher mass fraction contributed to higher elution efficiency. The elution efficiency improved slightly with the number of times of desorption increasing, which indicates that the resin had potential in cyclic utilization. (c) 2014 American Institute of Chemical Engineers Environ Prog, 34: 387-393, 2015

关键词： BP Deepwater Horizon Explosion & Oil Spill, 2010   ENVIRONMENTAL impact analysis   NONFICTION  

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关键词： techniques: interferometric   cosmological parameters   dark ages, reionization, first stars   large-scale structure of Universe  

摘要： The highly redshifted 21-cm line of neutral hydrogen has become recognized as a unique probe of cosmology from relatively low redshifts (z similar to 1) up through the Epoch of Reionization (EoR) (z similar to 8) and even beyond. To date, most work has focused on recovering the spherically averaged power spectrum of the 21-cm signal, since this approach maximizes the signal to noise in the initial measurement. However, like galaxy surveys, the 21-cm signal is affected by redshift space distortions, and is inherently anisotropic between the line of sight and transverse directions. A measurement of this anisotropy can yield unique cosmological information, potentially even isolating the matter power spectrum from astrophysical effects. However, in interferometric measurements, foregrounds also have an anisotropic footprint between the line of sight and transverse directions: the so-called foreground 'wedge'. Although foreground subtraction techniques are actively being developed, a 'foreground avoidance' approach of simply ignoring contaminated modes has arguably proven most successful to date. In this work, we analyse the effect of this foreground anisotropy in recovering the redshift space distortion signature in 21-cm measurements at both high and intermediate redshifts. We find the foreground wedge corrupts nearly all of the redshift space signal for even the largest proposed EoR experiments (Hydrogen Epoch of Reionization Array and the Square Kilometre Array), making cosmological information unrecoverable without foreground subtraction. The situation is somewhat improved at lower redshifts, where the redshift-dependent mapping from observed coordinates to cosmological coordinates significantly reduces the size of the wedge. Using only foreground avoidance, we find that a large experiment like Canadian Hydrogen Intensity Mapping Experiment can place non-trivial constraints on cosmological parameters.

关键词： Chromatography   Organic acids   Green chemistry   Langmuir isotherm   Van Deemter equation  

摘要： Bio-based organic acids are identified as very promising sources of renewable carbon. Currently their production costs are a major obstacle to their development and particularly because of complex downstream processes, using distillation or crystallization. Preparative chromatography was studied as an alternative to those processes. Two different ion exchange resins (anionic and cationic) were tested on synthetic solutions, a first step before studying the purification of a real fermentation broth. Firstly, adsorption isotherms were determined for each organic acid in single solute solution. They all fitted with the Langmuir model. Moreover in a first approximation, they could be considered as linear on cationic resin. Affinity coefficients, obtained by fitting, were compared to affinity coefficients determined during pulse tests. They were generally in good agreement, confirming that both methods are accurate. However, wider is the peak tailing on the pulse test and greater are the differences between measured values. In a second phase, the effect of the liquid flow rate on the column efficiency was studied for salts, glucose and lactic acid. The results were consistent with Van Deemter equation for lactic acid and glucose;salts were not retained at all. The linear part of Van Deemter equation is observed for liquid velocities between 0.4 and 4 m/h. (C) 2014 Elsevier B.V. All rights reserved.

关键词： Potassium   Strong acid cation   Resin   Equilibrium   Bottle-point method  

摘要： This paper relates to the importance of impact of the chosen bottle-point method when conducting ion exchange equilibria experiments. As an illustration, potassium ion exchange with strong acid cation resin was investigated due to its relevance to the treatment of various industrial effluents and groundwater. The "constant mass" bottle-point method was shown to be problematic in that depending upon the resin mass used the equilibrium isotherm profiles were different. Indeed, application of common equilibrium isotherm models revealed that the optimal fit could be with either the Freundlich or Temkin equations, depending upon the conditions employed. It could be inferred that the resin surface was heterogeneous in character, but precise conclusions regarding the variation in the heat of sorption were not possible. Estimation of the maximum potassium loading was also inconsistent when employing the "constant mass" method. The "constant concentration" bottle-point method illustrated that the Freundlich model was a good representation of the exchange process. The isotherms recorded were relatively consistent when compared to the "constant mass" approach. Unification of all the equilibrium isotherm data acquired was achieved by use of the Langmuir Vageler expression. The maximum loading of potassium ions was predicted to be at least 116.5 g/kg resin. (C) 2014 Elsevier B.V. All rights reserved.

关键词： 架空绝缘线   端部处理   等温松弛电流   老化因子   雷击测试  

摘要： 工程运行经验表明，架空绝缘线端部极易发生雷击断线现象。对不同端部处理方式的架空绝缘导线进行了雷击试验模拟，并基于等温松弛电流法研究了不同端部处理方式对架空绝缘线雷击绝缘特性的影响。通过对老化因子的分析发现，雷击脉冲试验后架空绝缘线端部老化因子都有不同程度的上升，反映了线路端部绝缘的劣化。由于雷电电弧移动以及潮气侵袭的原因，实验结果显示剥离后使用3M胶带密封的处理方式，雷击测试后表现出更好的绝缘特性。

关键词： 钢管混凝土组合框架   抗震性能   纤维梁单元   分层壳单元   IDA方法   塑性铰  

摘要： 基于有限元软件ABAQUS用户材料模型子程序二次开发技术,建立了钢管混凝土组合框架体系的数值模拟模型,该模型得到了以往研究者完成的钢管混凝土构件及组合框架结构低周往复荷载试验结果的验证。分别基于非线性纤维梁单元及分层壳单元模拟梁柱构件及楼板,用增量动力分析(IDA)方法对某9层钢管混凝土空间框架结构的抗震性能进行了研究,对某一地震动下结构由弹性阶段到屈服再到塑性阶段过程中的性能点、层间位移角、结构顶层谱加速度时程响应、框架塑性铰出铰顺序及基底剪力时程曲线进行了判定,为进一步评估钢管混凝土空间框架结构的抗震性能提供参考。

关键词： 综合管线   线侧下式   间距  

摘要： 文章主要以建成的几条铁路站区综合管线图为研究基础,分析了影响线下式站房与站台之间合理间距确定时需考虑的因素,包括房屋基础、地道出口挡墙、综合管线布置、楼扶梯基础等;研究了如何调整以上各因素的空间位置及结构尺寸,使其布局合理,达到既能施工方便、又能满足日后使用及养护维修要求,同时还可最大限度减少空间浪费的目的;得出了线侧下式车站站房与设有楼扶梯挡墙间间距至少为10 m的结论,同时提出在设有外挂式楼扶梯的站台上,将路肩式挡土墙与路堤式挡土墙结合设计的思路,以期对今后的设计有所启迪和帮助。