Anysotropic relaxivity measurements of solubilized multiwall carbon nanotubes suspensions reveal molecular orientation

Trabajo presentado al 20th Annual Meeting & Exhibition International Society for Magnetic Resonance in Medicine, celebrado en Melbourne (Australia) del 5 al 11 de Mayo de 2012.Peer Reviewe

Synergistic Antifungal Study of PEGylated Graphene Oxides and Copper Nanoparticles against Candida albicans

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).The coupling reactions of polyethylene glycol (PEG) with two different nano-carbonaceous materials, graphene oxide (GO) and expanded graphene oxide (EGO), were achieved by amide bond formations. These reactions yielded PEGylated graphene oxides, GO-PEG and EGO-PEG. Whilst presence of the newly formed amide links (NH-CO) were confirmed by FTIR stretches observed at 1732 cm−1 and 1712 cm−1, the associated Raman D- and G-bands resonated at 1311/1318 cm−1 and 1584/1595 cm−1 had shown the carbonaceous structures in both PEGylated products remain unchanged. Whilst SEM images revealed the nano-sheet structures in all the GO derivatives (GO/EGO and GO-PEG/EGO-PEG), TEM images clearly showed the nano-structures of both GO-PEG and EGO-PEG had undergone significant morphological changes from their starting materials after the PEGylated processes. The successful PEGylations were also indicated by the change of pH values measured in the starting GO/EGO (pH 2.6–3.3) and the PEGylated GO-PEG/EGO-PEG (pH 6.6–6.9) products. Initial antifungal activities of selective metallic nanomaterials (ZnO and Cu) and the four GO derivatives were screened against Candida albicans using the in vitro cut-well method. Whilst the haemocytometer count indicated GO-PEG and copper nanoparticles (CuNPs) exhibited the best antifungal effects, the corresponding SEM images showed C. albicans had, respectively, undergone extensive shrinkage and porosity deformations. Synergistic antifungal effects all GO derivatives in various ratio of CuNPs combinations were determined by assessing C. albicans viabilities using broth dilution assays. The best synergistic effects were observed when a 30:70 ratio of GO/GO-PEG combined with CuNPs, where MIC50 185–225 μm/mL were recorded. Moreover, the decreased antifungal activities observed in EGO and EGO-PEG may be explained by their poor colloidal stability with increasing nanoparticle concentrations.Peer reviewe

Simultaneous obtention of multicomponent ferroalloy and slag from black sands for the development of electrical arc welding consumables

10 páginas, 3 figuras, 8 tablas.[ES] En este trabajo se expone una caracterización química y mineralógica de las arenas negras del placer Mejías de Sagua de Tánamo, el más importante placer litoral de playa del noroeste de Cuba Oriental. A partir de estas caracterizaciones se desarrolla una estrategia de cálculo para la confección de la carga metalúrgica, que permite obtener, simultáneamente, al ser procesada por reducción carbotérmica en un homo de arco eléctrico, una ferroaleación multicomponente y una escoria útil para la confección de consumibles de soldadura por arco eléctrico. El polvo de la escoria obtenida se aglomera con vidrio líquido. Los pelets resultantes y su comportamiento en la soldadura automática por arco sumergido (SAW), presentan propiedades metalúrgicas y tecnológicas que satisfacen los requisitos de una matriz de un fundente aglomerado. La composición química de la ferroaleación multicomponente está constituida por elementos metálicos: vanadio, cromo, molibdeno, titanio y niobio (V, Cr, Mo, Ti y Nb) de alto valor metalúrgico y aleante, apropiada para la formulación de cargas aleantes de consumibles tanto para la soldadura manual (SMAW) como para la SAW.[EN] In this paper, chemical and mineralogical characterizations of the black sands of the Mejias placer of Sagua de Tánamo (the most important beach littoral placer of the northwest of oriental Cuba) are exposed. Starting from these characterizations a calculation strategy is developed for the making of the metallurgical load that allows to obtain simultaneously, when processed by carbothermic reduction in an electrical arc furnace, a multicomponent ferroalloy and a useful slag for the making of electric arch welding consumables. The powder of the obtained slag is agglomerated with liquid glass. The resulting pellets, due to their behavior on the submerged arc welding (SAW) present technological and metallurgical properties that correspond with the requirements of an agglomerated flux matrix. The chemical composition of the multicomponent ferroalloy is constituted by metallic elements of high metallurgical and alloyed values (V, Cr, Mo, Ti, Nb). It is appropriate for the formulation of consumables for manual welding (SMAW) and SAW, as well.Peer reviewe

Propiedades de flujo de suspensiones lateríticas concentradas: influencia de la mineralogía y de las características coloidales

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Química Agrícola, Geología y Geoquímica. Fecha de lectura: 25-4-199

Propiedades de flujo de suspensiones lateriticas concentradas Influencia de la mineralogia y de las caracteristicas coloidales

Centro de Informacion y Documentacion Cientifica (CINDOC). C/Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai

Impacto del sistema de evaluación de conocimientos y competencias en la enseñanza semipresencial en los Cursos de Adaptación a Grado en Ingeniería Mecánica y Eléctrica

SIN FINANCIACIÓNNo data 201

Coarse-Grained Molecular Dynamics of pH-Sensitive Lipids

pH-sensitive lipids represent a class of lipids that can be protonated and destabilized in acidic environments, as they become positively charged in response to low-pH conditions. They can be incorporated into lipidic nanoparticles such as liposomes, which are able to change their properties and allow specific drug delivery at the acidic conditions encountered in some pathological microenvironments. In this work, we used coarse-grained molecular-dynamic simulations to study the stability of neutral and charged lipid bilayers containing POPC (1-palmitoyl-2-oleoyl-sn-glycero-3- phosphocholine) and various kinds of ISUCA ((F)2-(imidazol-1-yl)succinic acid)-derived lipids, which can act as pH-sensitive molecules. In order to explore such systems, we used a MARTINIderived forcefield, previously parameterized using all-atom simulation results. We calculated the average area per lipid, the second-rank order parameter and the lipid diffusion coefficient of both lipid bilayers made of pure components and mixtures of lipids in different proportions, under neutral or acidic conditions. The results show that the use of ISUCA-derived lipids disturbs the lipid bilayer structure, with the effect being particularly marked under acidic conditions. Although morein depth studies on these systems must be carried out, these initial results are encouraging and the lipids designed in this research could be a good basis for developing new pH-sensitive liposomes.Sin financiación6.208 Q1 JCR 20211.176 Q1 SJR 2021No data IDR 2021UE

Technologies for the 21st century: Carbon nanotubes as adsorbents of metals

© 2014 CSIC. Nowadays and in the recent past when the word >nano> appeared in almost anything it attracted immediate attention and interest, this is why carbon nanotubes, since its discovery nearly twenty years ago, caught the interest of a wide scientific and industrial population to apply the somewhat amazing properties of these nanomaterials in a number of applications. Among them, the removal of toxic and sometimes profitable metals from aqueous streams appeared, due to its economical and social impact, as one of the targets for their uses. This paper reviews some recent advances (2009-2013 years) in the application of carbon nanotubes materials in the removal of a variety of metals from these aqueous streams.Peer Reviewe

Modelización molecular de la adsorción de proteínas y surfactantes iónicos sobre nanotubos de carbono

En este trabajo se estudian las interacciones que se establecen entre distintas moléculas de interés en aplicaciones biomédicas, en concreto la albúmina de suero fetal bovino (BSA) y los surfactantes dodecil sulfato de sodio (SDS) y dodecil bencen sulfonato de sodio (SDBS), con un nanotubo de carbono (CNT) mediante métodos computacionales de dinámica molecular. La adsorción de las dichas moléculas sobre la superficie del CNT se analiza siguiendo la evolución temporal de las distancias intermoleculares, así como calculando la energía de interacción molécula-CNT.UEM2014No data 2018UE

Nickel(II) removal by mixtures of Acorga M5640 and DP8R in pseudo-emulsion based hollow fiber with strip dispersion technology

This work presents the investigation of Ni(II) extraction from aqueous solution through pseudo-emulsion based hollow fiber strip dispersion (PSEHFSD) containing the mixture 2-hydroxy-5-nonylbenzaldehyde oxime+di(2-ethylhexyl) phosphoric acid/Exxsol D100 as extractant in the form of a pseudo-emulsion with H₂SO₄. The organic and aqueous strip phases are separated when the stirring device is stopped. The permeation of Ni(II) is investigated as a function of various experimental variables: hydrodynamic conditions, feed pH, extractants mixture concentration in the pseudo-emulsion, initial Ni(II) concentration in feed phase, H₂SO₄ concentration in the pseudo-emulsion as strippant. In PEHFSD, pseudo-emulsion is an emulsion that is formed temporarily between organic and stripping solutions. In this investigation, feed was circulated through the lumen side in counter-current mode. The selectivity of 2-hydroxy-5-nonylbenzaldehyde oxime+di(2-ethylhexyl) phosphoric acid/Exxsol D100 based PEHFSD toward different metals was also examined.3.155 JCR (2010) Q1, 28/193 Environmental sciencesUE