102 research outputs found

    Cerium, gallium and zinc containing mesoporous bioactive glasscoating deposited on titanium alloy

    Get PDF
    Surface modification is one of the methods for improving the performance of medical implants inbiological environment. In this study, cerium, gallium and zinc substituted 80%SiO2-15%CaO-5%P2O5mesoporous bioactive glass (MBG) in combination with polycaprolactone (PCL) were coated over Ti6Al4 Vsubstrates by dip-coating method in order to obtain an inorganic\u2014organic hybrid coating (MBG-PCL).Structural characterization was performed using XRD, nitrogen adsorption, SEM-EDXS, FTIR. The MBG-PCL coating uniformly covered the substrate with the thickness found to be more than 1 m. Glass andpolymer phases were detected in the coating along with the presence of biologically potent elementscerium, gallium and zinc. In addition, in vitro bioactivity was investigated by soaking the coated samplesin simulated body fluid (SBF) for up to 30 days at 37\u25e6C. The apatite-like layer was monitored by FTIR, SEM-EDXS and ICP measurements and it formed in all the samples within 15 days except zinc samples. In thisway, an attempt was made to develop a new biomaterial with improved in vitro bioactive response dueto bioactive glass coating and good mechanical strength of Ti6Al4 V alloy along with inherent biologicalproperties of cerium, gallium and zinc

    Exploitation of \u3ba-carrageenan aerogels as template for edible oleogel preparation.

    Get PDF
    In the current research, oleogels were prepared by using \u3ba-carrageenan aerogels as template. In particular, hydrogels containing increasing concentration (0.4, 1.0, and 2.0% w/w) of \u3ba-carrageenan were firstly converted into alcoholgel and subsequently dried by using supercritical CO2 to obtain aerogels. The latter were porous and structurally stable materials with high mechanical strength. The polymer content affected the aerogel structure: increasing the initial k-carrageenan concentration a coarser structure with larger polymer aggregates was obtained. However, the aerogel obtained at intermediate polymer concentration resulted the firmest one, probably due to the formation of a less aerated and more isotropic structure. Aerogels demonstrated a reduced capacity of water vapor sorption, remaining glassy and porous at room temperature at relative humidity lower than 60%. Aerogels showed a good capacity of oil absorption. The maximum oil loading capacity (about 80%) was obtained for aerogel containing the highest \u3ba-carrageenan content. Thus, it can be concluded that aerogels based on the structuring of water soluble polymers have potential as material for oil absorption and delivery. \ua9 2017 Elsevier Lt

    Application of Commercial Surface Pretreatments on the Formation of Cerium Conversion Coating (CeCC) over High-Strength Aluminum Alloys 2024-T3 and 7075-T6

    Get PDF
    The selection of appropriate surface pretreatments is one of the pending issues for the industrial application of cerium-based chemical conversion coatings (CeCC) as an alternative for toxic chromate conversion coating (CrCC). A two-step surface pretreatment based on commercial products has been successfully used here to obtain CeCC on AA2024-T3 and AA7075-T6. Specimens processed for 1 to 15 min in solutions containing CeCl3 and H2O2 have been studied by scanning electron microscopy coupled with energy-dispersive X-ray analysis (SEM-EDX), glow discharge optical emission spectroscopy (GDOES), potentiodynamic linear polarization (LP), electrochemical impedance spectroscopy (EIS), and neutral salt spray (NSS) tests. SEM-EDX showed that CeCC was firstly observed as deposits, followed by a general coverage of the surface with the formation of cracks where the coating was getting thicker. GDOES confirmed an increase of the CeCC thickness as the deposition proceed, the formation of CeCC over 7075 being faster than over 2024. There was a Ce-rich layer in both alloys and an aluminum oxide/hydroxide layer on 7075 between the upper Ce-rich layer and the aluminum matrix. According to LP and EIS, CeCC in all samples offered cathodic protection and comparable degradation in chloride-containing media. Finally, the NSS test corroborated the anti-corrosion properties of the CeCC obtained after the commercial pretreatments employed.This research was funded by the Ministry of Economy, Industry and Competitiveness of Spain/FEDER Program of the EU. Project: Optimizacion y viabilidad industrial del proceso de preparacion de capas de conversion basadas en cerio sobre aleaciones de aluminio. Reference MAT2014-60857-R. The APC was funded by Instituto Universitario de Investigacion Marina (INMAR) of the University of Cadiz and the Programa de Fomento e Impulso de la Actividad de Investigacion y Transferencia of the University of Cadiz

    Organoid models of fibrolamellar carcinoma mutations reveal hepatocyte transdifferentiation through cooperative BAP1 and PRKAR2A loss

    Get PDF
    Fibrolamellar carcinoma (FLC) is a lethal primary liver cancer, affecting young patients in absence of chronic liver disease. Molecular understanding of FLC tumorigenesis is limited, partly due to the scarcity of experimental models. Here, we CRISPR-engineer human hepatocyte organoids to recreate different FLC backgrounds, including the predominant genetic alteration, the DNAJB1-PRKACA fusion, as well as a recently reported background of FLC-like tumors, encompassing inactivating mutations of BAP1 and PRKAR2A. Phenotypic characterizations and comparisons with primary FLC tumor samples revealed mutant organoid-tumor similarities. All FLC mutations caused hepatocyte dedifferentiation, yet only combined loss of BAP1 and PRKAR2A resulted in hepatocyte transdifferentiation into liver ductal/progenitor-like cells that could exclusively grow in a ductal cell environment. BAP1-mutant hepatocytes represent primed cells attempting to proliferate in this cAMP-stimulating environment, but require concomitant PRKAR2A loss to overcome cell cycle arrest. In all analyses, DNAJB1-PRKACAfus organoids presented with milder phenotypes, suggesting differences between FLC genetic backgrounds, or for example the need for additional mutations, interactions with niche cells, or a different cell-of-origin. These engineered human organoid models facilitate the study of FLC

    Human fetal brain self-organizes into long-term expanding organoids

    Get PDF
    Human brain development involves an orchestrated, massive neural progenitor expansion while a multi-cellular tissue architecture is established. Continuously expanding organoids can be grown directly from multiple somatic tissues, yet to date, brain organoids can solely be established from pluripotent stem cells. Here, we show that healthy human fetal brain in vitro self-organizes into organoids (FeBOs), phenocopying aspects of in vivo cellular heterogeneity and complex organization. FeBOs can be expanded over long time periods. FeBO growth requires maintenance of tissue integrity, which ensures production of a tissue-like extracellular matrix (ECM) niche, ultimately endowing FeBO expansion. FeBO lines derived from different areas of the central nervous system (CNS), including dorsal and ventral forebrain, preserve their regional identity and allow to probe aspects of positional identity. Using CRISPR-Cas9, we showcase the generation of syngeneic mutant FeBO lines for the study of brain cancer. Taken together, FeBOs constitute a complementary CNS organoid platform.</p

    Notulae to the Italian alien vascular flora: 14

    Get PDF
    In this contribution, new data concerning the distribution of vascular flora alien to Italy are presented. It includes new records, confirmations, and status changes for Italy or for Italian administrative regions. Nomenclatural and distribution updates, published elsewhere, and corrections are provided as Suppl. materia

    Notulae to the Italian alien vascular flora: 14

    Get PDF
    In this contribution, new data concerning the distribution of vascular flora alien to Italy are presented. It includes new records, confirmations, and status changes for Italy or for Italian administrative regions. Nomenclatural and distribution updates, published elsewhere, and corrections are provided as Suppl. material

    Notulae to the Italian alien vascular flora: 11

    Get PDF
    In this contribution, new data concerning the distribution of vascular flora alien to Italy are presented. It includes new records, confirmations, exclusions, and status changes for Italy or for Italian administrative regions. Nomenclatural and distribution updates published elsewhere are provided as Suppl. material 1
    • …
    corecore