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Wang L.,Kunming University of Science and Technology | Wang L.,Wuxi Shunye Technology Co. | Yang J.,Wuxi Shunye Technology Co. | Yang J.,McGill University | And 7 more authors.
Colloids and Surfaces A: Physicochemical and Engineering Aspects | Year: 2016

Both mechanical and chemical durability of superhydrophobic (SH) surfaces are very important properties for industrial applications. In this paper, the durability of the Ultra-Ever Dry, as a commercial SH product, sprayed onto low carbon steel has been systematically studied by sand paper abrasion, waterfall/jet test and immersion in solution of different pH values as well as salt spray test. The results show that the degeneration of superhydrophobicity of the coating during the abrasion was mainly due to the loss of both the top layer of micro-scale bumps and their nanoparticles (NPs). Waterfall/jet impact could also cause the loss of NPs on the micro-scale bumps of the coating, which corresponds with the change of wettability. Different chemical processes elicit complex effects on the SH Surface. The coating is able to maintain its superhydrophobicity in solutions of pH 1-12, whereas a solution of pH 14 causes both chemical change and loss of NPs, and as a result, the loss of the water-repellent property. The salt spray test shows that the pitting corrosion on the surface and the degeneration of superhydrophobicity are mainly induced by morphological and surface chemical changes such as the formation of new Fe-O nanostructures that presented as pit-etching on the coating surface. The results also confirm that surperhydrophobictity degeneration of the SH coating surface by salt spray can be easily recovered through treatment with fluoroalkylsilane (FAS-17). © 2016 Elsevier B.V. Source

Li W.,Wuxi Shunye Technology Co. | Yang J.,Wuxi Shunye Technology Co. | Yang J.,McGill University | Yang J.,Rosalind and Morris Goodman Cancer Research Center | And 3 more authors.
Materials Research Express | Year: 2015

We report a simple route for the synthesis of several morphologies of self-assembling hierarchical Ni (OH)2 nanostructures, by the reaction of NiSO4 and NH4OH in aqueous solution, at a constant temperature, using neither surfactant nor template. Both morphology and microstructure depend on the concentrations of the reactants, the reaction temperature and the anions (Cl-, .., NO3 - and SO4 2-) present. The nanostructures have been characterized by scanning electron microscopy (SEM) and x-ray diffraction (XRD). When SO4 2-is used, irrespective of the presence of other anions, only microspheres of hierarchical Ni(OH)2 nanosheets are present, suggesting that this anion plays a critical role in microsphere formation. Electrochemical characterizations of Ni(OH)2 nanosheets show good supercapacitor performance, with relatively high capacity and excellent rate capability, indicating that these hierarchical Ni(OH)2 nanosheets are serious candidates for energy storage applications. The growth mechanism for nanosheet formation is discussed, based on SEM observations under different preparation conditions, detailing the transition from nanoparticles to nanowires to nanosheets. The specific surface area and the thickness of our Ni(OH)2 nanosheets have been determined to be 149.6 m2 g-1 and 20-30 nm, respectively. © 2015 IOP Publishing Ltd. Source

Archibald A.,Rosalind and Morris Goodman Cancer Research Center | Al-Masri M.,Rosalind and Morris Goodman Cancer Research Center | Liew-Spilger A.,Rosalind and Morris Goodman Cancer Research Center | McCaffrey L.,Rosalind and Morris Goodman Cancer Research Center | McCaffrey L.,McGill University
Molecular Biology of the Cell | Year: 2015

Epithelial cells are major sites of malignant transformation. Atypical protein kinase C (aPKC) isoforms are overexpressed and activated in many cancer types. Using normal, highly polarized epithelial cells (MDCK and NMuMG), we report that aPKC gain of function overcomes contact inhibited growth and is sufficient for a transformed epithelial phenotype. In 2D cultures, aPKC induced cells to grow as stratified epithelia, whereas cells grew as solid spheres of nonpolarized cells in 3D culture. aPKC associated with Mst1/2, which uncoupled Mst1/2 from Lats1/2 and promoted nuclear accumulation of Yap1. Of importance, Yap1 was necessary for aPKC-mediated overgrowth but did not restore cell polarity defects, indicating that the two are separable events. In MDCK cells, Yap1 was sequestered to cell-cell junctions by Amot, and aPKC overexpression resulted in loss of Amot expression and a spindle-like cell phenotype. Reexpression of Amot was sufficient to restore an epithelial cobblestone appearance, Yap1 localization, and growth control. In contrast, the effect of aPKC on Hippo/Yap signaling and overgrowth in NMuMG cells was independent of Amot. Finally, increased expression of aPKC in human cancers strongly correlated with increased nuclear accumulation of Yap1, indicating that the effect of aPKC on transformed growth by deregulating Hippo/ Yap1 signaling may be clinically relevant. © 2015 Mount and Wolin. Source

Li L.,Rosalind and Morris Goodman Cancer Research Center | Yang X.-J.,Rosalind and Morris Goodman Cancer Research Center | Yang X.-J.,McGill University
Cellular and Molecular Life Sciences | Year: 2015

Microtubules have important functions ranging from maintenance of cell morphology to subcellular transport, cellular signaling, cell migration, and formation of cell polarity. At the organismal level, microtubules are crucial for various biological processes, such as viral entry, inflammation, immunity, learning and memory in mammals. Microtubules are subject to various covalent modifications. One such modification is tubulin acetylation, which is associated with stable microtubules and conserved from protists to humans. In the past three decades, this reversible modification has been studied extensively. In mammals, its level is mainly governed by opposing actions of α-tubulin acetyltransferase 1 (ATAT1) and histone deacetylase 6 (HDAC6). Knockout studies of the mouse enzymes have yielded new insights into biological functions of tubulin acetylation. Abnormal levels of this modification are linked to neurological disorders, cancer, heart diseases and other pathological conditions, thereby yielding important therapeutic implications. This review summarizes related studies and concludes that tubulin acetylation is important for regulating microtubule architecture and maintaining microtubule integrity. Together with detyrosination, glutamylation and other modifications, tubulin acetylation may form a unique 'language' to regulate microtubule structure and function. © 2015 Springer Basel. Source

Tahmasebi S.,Rosalind and Morris Goodman Cancer Research Center | Ghorbani M.,Rosalind and Morris Goodman Cancer Research Center | Savage P.,Rosalind and Morris Goodman Cancer Research Center | Gocevski G.,Rosalind and Morris Goodman Cancer Research Center | And 2 more authors.
Stem Cells | Year: 2014

Sumoylation adds a small ubiquitin-like modifier (SUMO) polypeptide to the ε-amino group of a lysine residue. Reminiscent of ubiquitination, sumoylation is catalyzed by an enzymatic cascade composed of E1, E2, and E3. For sumoylation, this cascade uses Ubc9 (ubiquitin conjugating enzyme 9, now officially named ubiquitin conjugating enzyme E2I [UBE2I]) as the sole E2 enzyme. Here, we report that expression of endogenous Ubc9 increases during reprogramming of mouse embryonic fibroblasts (MEFs) into induced pluripotent stem (iPS) cells. In addition, this E2 enzyme is required for reprogramming as its suppression dramatically inhibits iPS cell induction. While Ubc9 knockdown does not affect survival of MEFs and immortalized fibroblasts, Ubc9 is essential for embryonic stem cell (ESC) survival. In addition, we have found that Ubc9 knockdown stimulates apoptosis in ESCs but not in MEFs. Furthermore, the knockdown decreases the expression of the well-known pluripotency marker Nanog and the classical reprogramming factors Klf4, Oct4, and Sox2 in ESCs. Together, these observations indicate that while dispensable for fibroblast survival, the sole SUMO E2 enzyme Ubc9 plays a critical role in reprogramming fibroblasts to iPS cells and maintaining ESC pluripotency. © AlphaMed Press 2013. Source

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