Spontaneous Cell Detachment and Reattachment in Cancer Cell Lines: An In Vitro Model of Metastasis and Malignancy

There is an unmet need for simplified in vitro models of malignancy and metastasis that facilitate fast, affordable and scalable gene and compound analysis. “Adherent” cancer cell lines frequently release “free-floating” cells into suspension that are viable and can reattach. This, in a simplistic way, mimics the metastatic process. We compared the gene expression profiles of naturally co-existing populations of floating and adherent cells in SW620 (colon), C33a (cervix) and HeLa (cervix) cancer cells. We found that 1227, 1367 and 1333 genes were at least 2-fold differentially expressed in the respective cell lines, of which 122 were shared among the three cell lines. As proof of principle, we focused on the anti-metastatic gene NM23-H1, which was downregulated both at the RNA and protein level in the floating cell populations of all three cell lines. Knockdown of NM23-H1 significantly increased the number of floating (and viable) cells, whereas overexpression of NM23-H1 significantly reduced the proportion of floating cells. Other potential regulators of these cellular states were identified through pathway analysis, including hypoxia, mTOR (mechanistic target of rapamycin), cell adhesion and cell polarity signal transduction pathways. Hypoxia, a condition linked to malignancy and metastasis, reduced NM23-H1 expression and significantly increased the number of free-floating cells. Inhibition of mTOR or Rho-associated protein kinase (ROCK) significantly increased cell death specifically in the floating and not the adherent cell population. In conclusion, our study suggests that dynamic subpopulations of free-floating and adherent cells is a useful model to screen and identify genes, drugs and pathways that regulate the process of cancer metastasis, such as cell detachment and anoikis.     

渣油催化临氢热转化钼铁双金属催化剂的研究

Replacement of precious single metal catalysts with cost-effective, highly-dispersed composite catalysts for catalytic hydrothermal conversion of residue holds tremendous promise for the residue upgrading technologies. Organic metals were added to the feed as the oil-soluble precursors, and transformed into the catalytic active phases in this work. Physical properties and structures of the composite catalysts had been investigated by X-ray fluorescence spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscope and transmission electron microscopy. The composite catalysts were found to be highly efficient in the catalytic hydrothermal conversion of both model compound and residue. Increased metal dispersion and synergistic effects of two metals played indispensable roles in such catalytic system. Results showed that under the test conditions in the article, the catalyst had the best catalytic performance when the mass ratio of molybdenum to iron was 1.5.     

Extrusion of highly filled flexible polymer sheet

Highly-filled polymer systems include color masterbatches, feedstocks for powder injection molding, and rigid sheets with high levels of flame retardants, but they have not been explored for flexible sheet. This work investigated the (a) selecting a polymer matrix with enough melt strength and flexibility to form a stable sheet with high filler loading, (b) the maximum achievable filler loading for the sheet, and (c) optimizing the process of extruding a highly-filled flexible polymer system. Extrusion grade low-density polyethylene (LDPE) provided sufficient flexibility and permitted a maximum filler loading of 36 vol% (~78 wt%). Good dispersion of the nanoparticle filler, however, required two passes through multiple screw extruders and a small reduction in the viscosity of the LDPE. Sheet with thickness of 415 μm, surface roughness of <1 μm, and sufficient flexibility was extruded continuously at a rate of 10 m/min., but it required a more traditional coat hanger manifold to prevent filler hang up in the sheet die. The filler particles were distributed uniformly through the core and skin of the sheet, giving the sheet good mechanical properties.     

分散式风电多点接入协调优化控制策略

针对分散式风电机组并网导致的配电网网损增加、电压稳定性降低等问题,文章提出一种分散式风电并网多点协调双层控制策略。首先,分析了分散式风电多点接入特性,研究分散式风电多点接入后的网损、电压分布和功率因数的关系,并提出最小网损和电压偏差为目标的双层优化控制策略。最后,基于IEEE-33节点进行仿真计算,结果表明,所提多点协调控制策略能够有效降低配电网网损和提升母线电压水平,增加系统的稳定性。与超前功率因数相比,滞后的功率因数能够增大风能消纳能力,提高供电可靠性,减少电压偏移水平。     

Anodic process on Cu−Al alloy in KF−AlF3−Al2O3 melts and suspensions

Anodic processes on Cu−10Al electrode in molten KF−AlF₃−Al₂O₃ (saturated) and suspensions were characterized using chronopotentiometric and cyclic voltammetric techniques. Effects of cryolite ratio (CR= x(KF)/x(AlF₃)), temperature and particle volume fraction (ϕ) on the electrochemical behaviour of the anode were demonstrated. Initially, the anode was polarised in the galvanostatic mode in melt and suspensions (ϕ=0.12, 0.15) at 750 °C with 0.4 A/cm² current density. The anode potential in melt varied between 2.5 and 3.2 V and in suspensions (ϕ= 0.12) between 3.3 and 3.4 V. XRD analysis was conducted to study the oxide phases on the anode surface. Anode limiting current densities and mass transfer coefficients drastically decreased with the increase of ϕ in the suspension. The results suggest that the Cu−10Al electrode works better in suspensions with CR of 1.4 and particle volume fraction of 0.09 at 800 °C.     

高温悬浮态下石灰石与菱镁矿热分解 特性比较及动力学研究

利用悬浮态高温炉,对比研究了菱镁矿及石灰石的热分解特性,探讨了其热解模型及动力学参数。结果表明:低温段(650~750℃)时,菱镁矿比石灰石易分解,达到一定高温后其分解速率相差不大;菱镁矿、石灰石在悬浮态下的热解机理均符合收缩核模型,其活化能分别为50 kJ/mol、79 kJ/mol;随着菱镁矿粒度的增大,其分解速率趋缓,分解表观活化能增大。     

Decreasing Filter Cake Resistance by Using Packing Structures

Packed beds used in absorption columns are evaluated to determine whether they can also be beneficial for cake‐forming filtrations. To assess this, model systems are characterized and separated by using a dead‐end filter cell. Filtrations are conducted with different packings; the filtrate amount over time and resulting turbidity are evaluated. Packings increase the filter cake resistance and the separation time of the cakes formed with approximately incompressible solids. However, they exhibit a positive effect on the filtration of a more complex, compressible substance; the process is not only accelerated, but also the quality of the obtained filtrate is not compromised. These results demonstrate potential in the use of packed beds for the filtration of complex biogenic suspensions.     

基于多参数特征保留的载荷谱加速耐久性编辑

为了得到时间更短加载效果相同的加速耐久性试验载荷谱,提出了基于多参数特征保留的载荷谱编辑方法。该方法同时考虑载荷谱的损伤、功率谱密度以及统计参数等信息,对零部件载荷谱的时间进行压缩。以汽车悬架螺旋弹簧的载荷谱为例,采用该方法进行缩减,同时从多个参数特征方面与传统的基于损伤保留的编辑方法所得到的载荷谱进行对比。为了进一步验证编辑效果,采用编辑谱和原始谱对弹簧进行疲劳仿真。结果表明,该方法能够有效缩短汽车零部件的载荷谱,可得到与原始载荷谱具有相同加载效果的编辑载荷谱。     

采用磁流变阻尼器的人体座椅悬架系统模糊ANFIS-PID复合控制技术研究

对座椅悬架用单出杆式磁流变阻尼器进行阻尼特性试验,并借助MATLAB多项式拟合工具箱对改进多项式模型中未知参数进行辨识。分析人体振动特性,建立五自由度人体座椅悬架模型。综合模糊控制器与自适应模糊神经推理系统(Adaptive Neuro-Fuzzy Inference System,ANFIS)整定PID控制器的优点,提出一种模糊ANFIS-PID复合控制策略。采用正弦信号作为外界激励,分别对被动悬架、传统模糊控制、ANFIS-PID控制及模糊ANFIS-PID复合控制人体座椅悬架系统进行仿真分析。结果表明,辨识得出的参数和建立的改进多项式模型均可满足后续仿真要求;采用模糊ANFIS-PID复合控制策略的隔振效果明显优于传统模糊控制及ANFIS-PID控制,能有效改善人体座椅悬架系统的行驶平顺性及驾乘人员乘坐舒适性。