Divergence of Intracellular Trafficking of Sphingosine Kinase 1 and Sphingosine-1-Phosphate Receptor 3 in MCF-7 Breast Cancer Cells and MCF-7-Derived Stem Cell-Enriched Mammospheres

Breast cancer MCF-7 cell-line-derived mammospheres were shown to be enriched in cells with a CD44+/CD24– surface profile, consistent with breast cancer stem cells (BCSC). These BCSC were previously reported to express key sphingolipid signaling effectors, including pro-oncogenic sphingosine kinase 1 (SphK1) and sphingosine-1-phosphate receptor 3 (S1P3). In this study, we explored intracellular trafficking and localization of SphK1 and S1P3 in parental MCF-7 cells, and MCF-7 derived BCSC-enriched mammospheres treated with growth- or apoptosis-stimulating agents. Intracellular trafficking and localization were assessed using confocal microscopy and cell fractionation, while CD44+/CD24- marker status was confirmed by flow cytometry. Mammospheres expressed significantly higher levels of S1P3 compared to parental MCF-7 cells (p < 0.01). Growth-promoting agents (S1P and estrogen) induced SphK1 and S1P3 translocation from cytoplasm to nuclei, which may facilitate the involvement of SphK1 and S1P3 in gene regulation. In contrast, pro-apoptotic cytokine tumor necrosis factor α (TNFα)-treated MCF-7 cells demonstrated increased apoptosis and no nuclear localization of SphK1 and S1P3, suggesting that TNFα can inhibit nuclear translocation of SphK1 and S1P3. TNFα inhibited mammosphere formation and induced S1P3 internalization and degradation. No nuclear translocation of S1P3 was detected in TNFα-stimulated mammospheres. Notably, SphK1 and S1P3 expression and localization were highly heterogenous in mammospheres, suggesting the potential for a large variety of responses. The findings provide further insights into the understanding of sphingolipid signaling and intracellular trafficking in BCs. Our data indicates that the inhibition of SphK1 and S1P3 nuclear translocation represents a novel method to prevent BCSCs proliferation.     

A Strategy of Liquid-Grafted Slippery Sponges with Simultaneously Enhanced Absorption and Desorption Performances for Crude Oil Spill Remediation

Crude oil spill accidents pose a worldwide environmental threat. Oleophilic and hydrophobic absorbents that can selectively absorb oil from water have shown promising application potential in oil spill remediation. Simultaneous optimization of the absorption and desorption speed of absorbents towards oil is highly desirable for their recyclable usage, but remains a great challenge, because these two properties are generally conflicting. Here, a facile and ingenious strategy is proposed to tackle the above challenge via surface modification of porous sponges with highly flexible linear polydimethylsiloxane (LPDMS) brushes. The LPDMS brushes feature liquid-like properties at room temperature owing to its extremely low glass transition temperature, and act as a covalently-grafted lubrication layer throughout the 3D network channels of the sponge, which can minimize contact angle hysteresis and reduce friction between oil and sponge channel. Compared to the prevalent cross-linked polydimethylsiloxane (CPDMS) modification strategy, sponges modified with LPDMS brushes not only shows significantly enhanced absorption speed, but also exhibits superior desorption dynamics towards viscous crude oils. The design strategy of slippery sponges with liquid-like molecules may open a new avenue for developing advanced absorbents with simultaneously enhanced absorption and desorption performances for liquid separation and purification applications.     

地下环境中电子设备的腐蚀与防护

程环境中电子设备所承受的湿度、温度、腐蚀性气体、空气沉积物、微生物等环境应力因素及其腐蚀效应，概述总结了电子设备腐蚀机制及主要类型，并提出电子设备设计与使用中抑制腐蚀的措施.     

Defect classification using a new feature for pulsed eddy current sensors

The objective of this study is to identify defects such as surface cracks, subsurface defects and metal losses using feature based pulsed eddy current sensors. A new feature, termed as the rising point, related to the propagation time of electromagnetic waves in metallic targets is proposed for defect classification. Experimental studies of the validation, robustness of the new feature of rising time are reported. In addition to other features, defects can be detected and quantified robustly and lift-off can also be derived from the rising time. Conclusion and further work are derived on the basis of the findings.     

钛酸钡中的硼间隙及其对PTCR效应的影响

通过B2O3蒸汽掺杂，钛酸钡晶胞膨胀，表明硼离子可以进入钛酸钡晶格中形成硼间隙。B2O3蒸汽掺杂使含Y钛酸钡陶瓷室温电阻率下降，升阻比提高。同样的烧结条件下，钛酸钡陶瓷的PTCR效应随B2O3蒸汽掺杂源的浓度升高而升高。硼间隙和／或相关缺陷络合物可以形成电子捕获中心，从而提高PTCR效应。     

Experiment and simulation study of 3D magnetic field sensing for magnetic flux leakage defect characterisation

Magnetic flux leakage (MFL) testing is widely used to detect and characterise defects in pipelines, rail tracks and other structures. The measurement of the two field components perpendicular to the test surface and parallel to the applied field in MFL systems is well established. However, it is rarely effective when the shapes of the specimens and defects with respect to the applied field are arbitrary. In order to overcome the pitfalls of traditional MFL measurement, measurement of the three-dimensional (3D) magnetic field is proposed. The study is undertaken using extensive finite element analysis (FEA) focussing on the 3D distribution of magnetic fields for defect characterisation and employing a high sensitivity 3-axis magnetic field sensor in experimental study. Several MFL tests were undertaken on steel samples, including a section of rail track. The experimental and FEA test results show that data from not only the x- and z-axes but also y-axis can give comprehensive positional information about defects in terms of shape and orientation, being especially advantageous where the defect is aligned close to parallel to the applied field. The work concludes that 3D magnetic field sensing could be used to improve the defect characterisation capabilities of existing MFL systems, especially where defects have irregular geometries.     

撞击流—旋转填料床反应器的微观混合性能研究

采用化学偶合法 ,对撞击流—旋转填料床反应器内微观混合进行了实验研究 ,得到了转速、喷嘴间距、射流速度及浓度等因素对离集指数Xs的影响规律 ,并对其进行了定性的分析。结果表明撞击流—旋转填料床反应器中微观混合能被极大地强化 ,可成为适合快速反应新型反应设备     

Spectroscopic studies of copper, silver and gold-metallothioneins

Metallothionein is a ubiquitous protein with a wide range of proposed physiological roles, including the transport, storage and detoxification of essential and nonessential trace metals. The amino acid sequence of isoform 2a of rabbit liver metallothionein, the isoform used in our spectroscopic studies, includes 20 cysteinyl groups out of 62 amino acids. Metallothioneins in general represent an impressive chelating agent for a wide range of metals. Structural studies carried out by a number of research groups (using (1)H and (113)Cd NMR, X-ray crystallography, more recently EXAFS, as well as optical spectroscopy) have established that there are three structural motifs for metal binding to mammalian metallothioneins. These three structures are defined by metal to protein stoichiometric ratios, which we believe specifically determine the coordination geometry adopted by the metal in the metal binding site at that metal to protein molar ratio. Tetrahedral geometry is associated with the thiolate coordination of the metals in the M(7)-MT species, for M = Zn(II), Cd(II), and possibly also Hg(II), trigonal coordination is proposed in the M(11-12)-MT species, for M = Ag(I), Cu(I), and possibly also Hg(II), and digonal coordination is proposed for the metal in the M(17-18)-MT species for M = Hg(II), and Ag(I). The M(7)-MT species has been completely characterized for M = Cd(II) and Zn(II). (113)Cd NMR spectroscopic and x-ray crystallographic data show that mammalian Cd(7)-MT and Zn(7)-MT have a two domain structure, with metal-thiolate clusters of the form M(4)(S(cys))(11) (the alpha domain) and M(3)(S(cys))(9) (the beta domain). A similar two domain structure involving Cu(6)(S(cys))(11) (alpha) and Cu(6)(S(cys))(9) (beta) copper-thiolate clusters has been proposed for the Cu(12)-MT species. Copper-, silver- and gold-containing metallothioneins luminesce in the 500-600 nm region from excited triplet, metal-based states that are populated by absorption into the 260-300 nm region of the metal-thiolate charge transfer states. The luminescence spectrum provides a very sensitive probe of the metal-thiolate cluster structures that form when Ag(I), Au(I), and Cu(I) are added to metallothionein. CD spectroscopy has been used in our laboratory to probe the formation of species that exhibit well-defined three-dimensional structures. Saturation of the optical signals during titrations of MT with Cu(I) or Ag(I) clearly show formation of unique metal-thiolate structures at specific metal:protein ratios. However, we have proposed that these M=7, 12 and 18 structures form within a continuum of stoichiometries. Compounds prepared at these specific molar ratios have been examined by X-ray Absorption Spectroscopy (XAS) and bond lengths have been determined for the metal-thiolate clusters through the EXAFS technique. The stoichiometric ratio data from the optical experiments and the bond lengths from the XAS experiments are used to propose structures for the metal-thiolate binding site with reference to known inorganic metal-thiolate compounds.     

混凝浑液面沉速与混凝剂投加量的关系研究

探讨了黄河高浊度水混凝沉淀浑液面沉速与自然沉速之间的相关性,经过对实验数据进行线性回归提出了混凝过程中浑液面沉速与自然沉速、含沙量、PAM投加量之间的经验公式。运用该经验公式得出的浑液面沉速计算值与实测相对误差在0.43%～12.27%之间。     

苯酚羟基化制邻苯二酚催化剂的活性评价

对苯酚羟基化反应铁复合氧化物类催化剂进行了活性评价的实验研究 ,实验表明 ,Cat980 5的选择性好 ,但邻对位比倒置 ,Cat980 8的选择性差 ,但邻对位比正常 ,其性能与国外催化剂的性能相近