Carbon nanotubes (CNTs)/La0.6Sr0.4Co0.8Fe0.2O3−δ (LSCF) composite films have been fabricated by electrophoretic codeposition on Ce0.9Gd0.1O1.95 (CGO) substrates. CNTs are used as a sacrificial phase to produce ordered porous LSCF cathodes for intermediate temperature solid oxide fuel cells. The synthesis of LSCF powder by a modified sol–gel route is presented. The possible mechanism of formation of CNT/LSCF composite nanoparticles in suspension is discussed. Moreover the optimal suspension composition and the conditions for achieving successful electrophoretic deposition (EPD) of CNTs/LSCF composite nanoparticles were evaluated. Experimental results showed that the CNTs were homogeneously distributed and mixed with LSCF nanoparticles forming a mesh‐like structure, which resulted in a highly porous LSCF film when the CNTs were burned out during heat treatment in air at 800°C for 2 h. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X‐ray diffraction (XRD) techniques were employed to characterize the microstructure of the precursors and of the composite films.
The electrophoretic deposition (EPD) technique was developed for depositing TiO2 films on stainless steel (SS) and titanium substrates. Titania coatings were obtained in conditions of optimal solution stability using acetylacetone suspensions of TiO2 nanoparticles and I2 at pH≈ 5. Deposition tests were carried out at 10V for varying times. The deposit thickness was seen to increase with EPD time, revealing that the deposits grew quickly for times <120 s, reaching a saturation value at longer times. The substrates were treated by physical and chemical methods before EPD in order to improve the adhesion of the films. The EPD coatings were sintered at 700, 800 and 900 °C under controlled argon atmosphere or in vacuum to study the influence of sintering atmosphere on crystalline phase transformation. The TiO2 coatings were characterized by XRD using Rietveld analysis. The results showed that TiO2 films on Ti substrates (chemically leached before deposition) had better adherence, homogeneity and density than those on SS. The coatings sintered al 700°C in vacuum resulted in a major proportion of anatasa phase. The porosity of the titania coatings sintered at 700°C (2 hr) in vacuum was calculated to be 19% .
The Vacuole Membrane Protein 1 -VMP1-is a pancreatitis-associated transmembrane protein whose expression triggers autophagy in several human diseases. In the current study, we unveil the mechanism through which this protein induces autophagosome formation in mammalian cells. We show that VMP1 autophagy-related function requires its 20-aminoacid C-terminus hydrophilic domain (VMP1-AtgD). This is achieved through its direct binding to the BH3 motif of Beclin 1 leading to the formation of a complex with the Class III phosphatidylinositol-3 kinase (PI3K) hVps34, a key positive regulator of autophagy, at the site where autophagosomes are generated. This interaction also concomitantly promotes the dissociation of Bcl-2, an autophagy inhibitor, from Beclin 1. Moreover, we show that the VMP1-Beclin 1-hVps34 complex favors the association of Atg16L1 and LC3 with the autophagosomal membranes. Collectively, these findings reveal that VMP1 expression recruits and activates the Class III PI3K complex at the site of autophagosome formation during mammalian autophagy.
Autophagy is an evolutionarily conserved transport pathway that involves the sequestration and delivery of cytoplasmic material into the lysosome, where it is degraded and recycled 1 . This catabolic process is involved in the turnover of long-lived proteins and other cellular macromolecules, and it might play a protective role in tumor development, aging, cell death, and intracellular pathogen invasions 2,3 .Macroautophagy (hereafter autophagy) involves the formation of double-membrane autophagosomes around the targeted cargoes, which include large structures such as organelles and protein aggregates. Autophagosomes then fuse with lysosomes exposing their cargoes to the hydrolytic content of this organelles 4 . This cellular process essential to maintain cellular homeostasis is regulated in an analogous manner to secretion and endocytosis, where related molecules on distinct organelle membranes mediate the flux of vesicular transport by proteinprotein interactions. Since the discovery of yeast autophagy-related (Atg) proteins 5 , autophagosome formation has been dissected at the molecular level but a lot of questions about the molecular mechanism underlying this process remain unanswered. Autophagosomes can be considered unique organelles because they do not contain marker proteins of other subcellular compartments 6 . In mammalian cells, the sequential association of at least a subset of the Atg proteins leads to the assembly of the pre-autophagosomal structures (PAS), which is believed to be the site where the precursor structure of the autophagosomes, the phagophores, are generated 7 . The PAS and phagophore formation also requires phosphatidylinositol 3-phosphate (PI3P) 8 and it is believed to be associated to specific subdomains of the endoplasmic reticulum (ER) termed omegasomes 9,10 . Among the key mediators initiating autophagosome formation, there is a set of evolutionarily conserved Atg. gene products; the kinasecontaining Ulk1/2 complex (Atg1 in yeast)...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.