Search results for "Chemical engineering"
showing 10 items of 5892 documents
Response of human chondrocytes to a non-uniform distribution of hydrophilic domains on poly (ethyl acrylate-co-hydroxyethyl methacrylate) copolymers.
2005
A series of polymer and copolymer networks with varying hydrophilicity and distribution of the hydrophilic groups was synthesized and biologically tested with monolayer culture of human chondrocytes in vitro. Cell viability (MTT), proliferation (BrdU incorporation) and aggrecan expression (PG ELISA) were quantified at 7 and 14 days from seeding. Both assays (MTT and BrdU) showed complementary results that are consistent with positive cellular adhesion on the material. When human chondrocytes were cultured on polymer substrates in which the hydrophilic groups were homogeneously distributed, hydrophobic substrates showed higher values in all the biological parameters analysed. Adhesion, proli…
"Partial oxidation of methane and methanol on FeOx-, MoOx- and FeMoOx -SiO2 catalysts prepared by sol-gel method: a comparative study"
2020
[EN] FeOx-, MoOx and FeMoOx-SiO2 materials prepared by a sol-gel procedure have been evaluated as catalysts for the partial oxidation of methane and methanol. The effect of decreasing the pH of the synthesis gel on the chemical nature of FeOx and MoOx species has been investigated. Characterization results show that low pH improves the dispersion of metal oxide species present in SiO2 matrix. For FeOx/SiO2 materials, the presence of dispersed FeOx species (rather than bulk Fe2O3) improves the selectivity to formaldehyde in the partial oxidation of methane and methanol. For FeMoOx/SiOx catalysts, dispersed species favor the selectivity to formaldehyde only for methane oxidation. In contrast,…
Electrochemical treatment of aqueous solutions of catechol by various electrochemical advanced oxidation processes: Effect of the process and of oper…
2017
Abstract Catechol, one of the most abundant compounds in olive mills wastewaters, which is generated in the Fenton degradation of various aromatic compounds, is a toxic, possible carcinogen, persistent pollutant and it is not readily biodegradable. Hence, its degradation requires the utilization of advanced oxidation processes (AOPs). Here, the electrochemical treatment of aqueous solutions of catechol was investigated. The utilization of various electrochemical processes, such as electro-Fenton (EF), direct anodic oxidation (AO), indirect oxidation by electro-generated active chlorine and coupled processes was investigated. Furthermore, the effect of various operating conditions (including…
Mixed Ligand Shell Formation upon Catechol Ligand Adsorption on Hydrophobic TiO2 Nanoparticles
2019
Modifying the surfaces of metal oxide nanoparticles (NPs) with monolayers of ligands provides a simple and direct method to generate multifunctional coatings by altering their surface properties. T...
El capital psíquico. Aportes de la Psicología Positiva.
2006
The article presents a brief analysis of the central proposals of contemporary Positive Psychology. The notion of Psychologiocal Capital is presented and a proposal for categorization of its principal components in terms of cognitive, affective and psychosocial processes is explained.
Fabrication of polyelectrolyte multilayered vesicles as inhalable dry powder for lung administration of rifampicin
2014
A polyelectrolyte complex based on chitosan and carrageenan was used to coat rifampicin-loaded vesicles and obtain a dry powder for inhalation by spray-drying. The polymer complexation on vesicle surface stabilized them and improved their adhesion on airways and epithelia cells. Uncoated liposomes were small in size, negatively charged and able to incorporate large amounts of rifampicin (70%). Coated vesicles were still able to load adequate amounts of drug (∼70%) but the coating process produced larger particles (1 μm) that were positively charged and with a spherical shape. Aerosol performances, evaluated using the next-generation impactor, showed that coated vesicles reached the 50% of f…
Use of the Cultex® Radial Flow System as an in vitro exposure method to assess acute pulmonary toxicity of fine dusts and nanoparticles with special …
2013
Exposure of the respiratory tract to airborne particles (including metal-dusts and nano-particles) is considered as a serious health hazard. For a wide range of substances basic knowledge about the toxic properties and the underlying pathomechanisms is lacking or even completely missing. Legislation demands the toxicological characterization of all chemicals placed on the market until 2018 (REACH). As toxicological in vivo data are rare with regard to acute lung toxicity or exhibit distinct limitations (e.g. inter-species differences) and legislation claims the reduction of animal experiments in general ("3R" principle), profound in vitro models have to be established and characterized to m…
Toward minimal bacterial cells: evolution vs. design.
2008
Abstract Recent technical and conceptual advances in the biological sciences opened the possibility of the construction of newly designed cells. In this paper we review the state of the art of cell engineering in the context of genome research, paying particular attention to what we can learn on naturally reduced genomes from either symbiotic or free living bacteria. Different minimal hypothetically viable cells can be defined on the basis of several computational and experimental approaches. Projects aiming at simplifying living cells converge with efforts to make synthetic genomes for minimal cells. The panorama of this particular view of synthetic biology lead us to consider the use of d…
Utilization of metabolic energy in treatment of ocular surface disorders: polyphosphate as an energy source for corneal epithelial cell proliferation.
2019
Impaired regeneration of the corneal epithelium, as found in many ocular surface diseases, is a major clinical problem in ophthalmology. We hypothesized that corneal epithelial regeneration can be promoted by the physiological, energy-delivering as well as “morphogenetically active” polymer, inorganic polyphosphate (polyP). Corneal limbal explants (diameter, 4 mm) were cultivated on collagen-coated well plates in the absence or presence of polyP (chain length, ∼40 Pi units; 50 μg ml−1) or human platelet lysate (hp-lysate; 5% v/v). Cell outgrowth and differentiation were analyzed after staining with DRAQ5 (nuclei) and rhodamine phalloidin (cytoskeleton), as well as by environmental scanning …
Double In Utero Electroporation to Target Temporally and Spatially Separated Cell Populations.
2020
In utero electroporation is an in vivo DNA transfer technique extensively used to study the molecular and cellular mechanisms underlying mammalian corticogenesis. This procedure takes advantage of the brain ventricles to allow the introduction of DNA of interest and uses a pair of electrodes to direct the entrance of the genetic material into the cells lining the ventricle, the neural stem cells. This method allows researchers to label the desired cells and/or manipulate the expression of genes of interest in those cells. It has multiple applications, including assays targeting neuronal migration, lineage tracing, and axonal pathfinding. An important feature of this method is its temporal a…