Metodología para estudios histológicos pulpares en ratas

La pulpotomía es uno de los tratamientos más frecuentes en odontopediatría, siendo hasta ahora el formocresol el fármaco más frecuentemente utilizado, pero su uso está siendo discutido debido a su potencial toxicidad. Existen distintas alternativas; agentes como el glutaraldehído y el sulfato férrico, materiales biocompatibles como el colágeno, hueso liofilizado y proteínas morfogenéticas formadoras de hueso, o técnicas como la electrocoagulación o la aplicación de láser. Por ello, son fundamentales, no sólo los estudios clínicos y radiológicos, sino también los estudios histológicos que nos muestran la respuesta del tejido pulpar ante la aplicación de los distintos materiales o técnicas. Estos estudios se realizan con diferentes especies animales y a su vez con distinta metodología. El objetivo de este trabajo ha sido describir una técnica para realizar estudios pulpares en molares de rata y estudiar la respuesta histológica que se observa en una exposición pulpar con la aplicación posterior de un agente como el hueso liofilizado. Nuestros resultados destacan que la técnica desarrollada para las exposiciones pulpares en ratas es adecuada y reproducible en otros estudios sobre el efecto de los distintos fármacos en el tejido pulpar

Estado actual de las pulpotomías con electrocoagulación

En la actualidad son varios los fármacos que se han utilizado para las pulpotornías,siendo el formocresol el más difundido. No obstante su uso está discutido por sus efectos tóxicos, su potencial mutagénico y carcinogénico y su respuesta inmunológica. Por este motivo la investigación se ha encaminado a la búsqueda de técnicas o fármacos menos tóxicos. Se pensó en la electrocoagulación como método alternativo a la aplicación de fármacos. Actualmente son varios los estudios que se han llevado a cabo para evaluar los resultados clínicos, radiológicos e histológicos de las pulpotomías con electrocoagulación

Comparative study on properties of starch films obtained from potato, corn and wheat using 1-ethyl-3-methylimidazolium acetate as plasticizer

Starch films are gaining attention as substitutes of synthetic polymers due to their biodegradability and low cost. Some ionic liquids have been postulated as alternatives to glycerol, one of the best starch plasticizers, due to their great capacity to form hydrogen bonds with starch and hence great ability of preventing starch retrogradation and increasing film stability. In this work, [emim+][Ac−]-plasticized starch films were prepared from potato, corn and wheat starch. The effect of starch molecular structure in terms of granular composition (amylose and phosphate monoester contents) and molecular weight (Mw) on film properties was evaluated. Potato starch films were the most amorphous because of the higher Mw and phosphate monoester content of potato starch, both contributing to a lower rearrangement of the starch chains making the crystallization process difficult. In contrast, corn and wheat starches lead to more crystalline films because of their lower Mw, which may imply higher mobility and crystal growth rate, and lower phosphate monoester content. This more crystalline structure could be the responsible of their better mechanical properties. [emim+][Ac−] can be considered suitable for manufacturing starch films showing corn and wheat starch films similar properties to synthetic low-density polyethylene, but involving a simple and environmentally-friendly process.This work was partially supported from the European Commission, European-Union and Ministerio de Economía y Competitividad (MINECO), Spain (Ref. CTQ2016-78246-R) and Generalitat Valenciana (Project PROMETEOII/2014/007). M.G. Montalbán acknowledges support from Ministerio de Economía y Competitividad (MINECO) (Juan de la Cierva-Formación contract, Ref. FJCI-2016-28081)

Custom-Made Chemically Modified Graphene Oxide to Improve the Anti-Scratch Resistance of Urethane-Acrylate Transparent Coatings

In this work, a thermoset ultraviolet (UV)-cured polyurethane-acrylate resin was doped with different chemically-modified graphene obtained from a commercial graphene oxide (GO): as-received GO, chemically reduced GO (rGO), GO functionalized with vinyltriethoxysilane (VTES) (GOvtes), and GO functionalized with VTES and subsequently reduced with a chemical agent (rGOvtes). Modified graphene was introduced in the oligomer component via solvent-assisted process using acetone, which was recovered after completion of the process. Results indicate that the GO-doped oligomers produce cured coatings with improved anti-scratch resistance (above the resistance of conventional coatings), without surface defects and high transparency. The anti-scratch resistance was measured with atomic force microscopy (AFM). Additionally, results are presented in terms of Wolf–Wilburn scale, a straightforward method widely accepted and employed in the coating industry.This research was funded by MINISTERIO DE ECONOMÍA Y COMPETITIVIDAD (MINECO) of Spain (CTQ2014-54772-P and CTQ2013-44213-R); and GENERALITAT VALENCIANA (ROMETEOII/2014/007)

Influence of Starch Composition and Molecular Weight on Physicochemical Properties of Biodegradable Films

Thermoplastic starch (TPS) films are considered one of the most promising alternatives for replacing synthetic polymers in the packaging field due to the starch biodegradability, low cost, and abundant availability. However, starch granule composition, expressed in terms of amylose content and phosphate monoesters, and molecular weight of starch clearly affects some film properties. In this contribution, biodegradable TPS films made from potato, corn, wheat, and rice starch were prepared using the casting technique. The effect of the grain structure of each starch on microstructure, transparency, hydration properties, crystallinity, and mechanical properties of the films, was evaluated. Potato starch films were the most transparent and corn starch films the most opaque. All the films had homogeneous internal structures—highly amorphous and with no pores, both of which point to a good starch gelatinization process. The maximum tensile strength (4.48–8.14 MPa), elongation at break (35.41–100.34%), and Young’s modulus (116.42–294.98 MPa) of the TPS films were clearly influenced by the amylose content, molecular weight, and crystallinity of the film. In this respect, wheat and corn starch films, are the most resistant and least stretchable, while rice starch films are the most extensible but least resistant. These findings show that all the studied starches can be considered suitable for manufacturing resistant and flexible films with similar properties to those of synthetic low-density polyethylene (LDPE), by a simple and environmentally-friendly process.This work was partially supported by the European Commission (FEDER/ERDF), the Spanish MINECO (Ref. CTQ2016-78246-R), and Generalitat Valenciana (Project PROMETEOII/2014/007). M.G.M. acknowledges support from MINECO (Juan de la Cierva-Formación contract, Ref. FJCI-2016-28081)

Catalytic Ozonation Using Edge-Hydroxylated Graphite-Based Materials

"This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Sustainable Chemistry & Engineering, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acssuschemeng.9b04646"[EN] This work reports the catalytic ozonation activity of high surface area graphite materials selectively functionalized at the edges with hydroxyl groups. The graphite-based catalyst shows higher activity than the parent graphite, commercial activated carbon, commercial multiwall carbon nanotubes, commercial diamond nanoparticles, graphene oxide, or reduced graphene oxide. Importantly, the catalytic activity of the graphite-based material is also higher than those of benchmark ozonation catalysts such as Co3O4 or Fe2O3. The graphite catalyst was reused up to 10 times with only a minor decrease in the catalytic activity. Catalytic activation of O-3 leads to the generation of hydroperoxide radicals and O-1(2). These results have been interpreted as derived from the combination of a suitable work function and the presence of phenolic/semiquinone-like redox pairs, as well as high dispersibility in water due to the presence of -OH groups. This work highlights the possibility of engineering active and stable carbocatalysts for reactions typically promoted by transition metals.Financial support by the Spanish Ministry of Science and Innovation (Severn Ochoa and RTI2018-098237-CO21) and Generalitat Valenciana (Prometeo 2017/083) is gratefully acknowledged. S.N. is thankful for financial support from the Fundacion Ramon Areces (XVIII Concurso Nacional para la Adjudication de Ayudas a la Investigacion en Ciencias de la Vida y de la Materia, 2016), Ministerio de Ciencia, Innovacion y Universidades RTI2018-099482-A-I00 project and Generalitat Valenciana grupos de investigacion consolidables 2019 (ref: AICO/2019/214) project.Bernat-Quesada, F.; Espinosa-López, JC.; Barbera, V.; Alvaro Rodríguez, MM.; Galimberti, M.; Navalón Oltra, S.; García Gómez, H. (2019). Catalytic Ozonation Using Edge-Hydroxylated Graphite-Based Materials. ACS Sustainable Chemistry & Engineering. 7(20):17443-17452. https://doi.org/10.1021/acssuschemeng.9b04646S174431745272

Engineering of activated carbon surface to enhance the catalytic activity of supported cobalt oxide nanoparticles in peroxymonosulfate activation

[EN] Commercial activated carbon has been functionalized by chemical or thermal treatments to introduce surface oxygen functional groups able to anchor small cobalt nanoparticles with superior catalytic activity for peroxymonosulfate activation. The resulting activated carbon supports where characterized by combustion elemental analysis, Fourier-transformed infrared spectroscopy, Raman spectroscopy, isothermal N-2 adsorption, temperature programmed desorption/mass spectrometry, X-ray diffraction and scanning electron microscopy. Activated carbon functionalization by nitric acid resulted the most appropriated method to provide a higher population of oxygenated functional groups able to anchor small cobalt nanoparticles. The catalytic activity of supported oxidized metal nanoparticles (4.7 +/- 0.05 nm) was higher than analogous non-oxidized cobalt nanoparticles (2.9 +/- 0.14 nm). The use of analogous supported oxidized iron or copper nanoparticles resulted in lower catalytic activity. Importantly, the supported oxidized cobalt nanoparticles at 0.2 wt% loading exhibit higher activity than benchmark catalysts such as unsupported Co3O4 solid or even homogeneous Co2+ ions. This is a reflection of the relatively low estimated activation energy for both processes, peroxymonosulfate decomposition and phenol degradation. The estimated activation energy values are about 30 and 32 kJ mol(-1). The stability of the most active catalyst was assessed by performing eight consecutive uses without observing decrease of catalytic activity, neither metal leaching or metal nanoparticle aggregation. Turnover numbers/turnover frequencies values as high as 440(5)/8.10(5)h(-1) for peroxymonosulfate activation and 39.10(3)/68.10(3) h(-1) for phenol degradation at pH 7 and 20 degrees C have been estimated, respectively. Electron paramagnetic resonance measurements and selective quenching experiments revealed that the generated sulfate radicals from peroxymonosulfate rapidly are transformed in highly reactive hydroxyl radicals. In excellent agreement with previous reports, this work demonstrates the importance of an adequate activated carbon functionalization to obtain superior and stable catalysts for peroxymonosulfate activation.Financial support by the Spanish Ministry of Economy and Competitiveness (Severo Ochoa, CTQ2015-65963-CQ-R1) and CTQ2014-53292-R is gratefully acknowledged. Generalitat Valenciana is also thanked for funding (Prometeo 2017/083). S.N. thanks financial support by the Fundacion Ramon Areces (XVIII Concurso Nacional para la Adjudicacion de Ayudas a la Investigacion en Ciencias de la Vida y de la Materia, 2016).Espinosa-López, JC.; Manickam-Periyaraman, P.; Bernat-Quesada, F.; Sivanesan, S.; Alvaro Rodríguez, MM.; García Gómez, H.; Navalón Oltra, S. (2019). Engineering of activated carbon surface to enhance the catalytic activity of supported cobalt oxide nanoparticles in peroxymonosulfate activation. Applied Catalysis B Environmental. 249:42-53. https://doi.org/10.1016/j.apcatb.2019.02.043S425324

Assessment of Physico-Chemical and Toxicological Properties of Commercial 2D Boron Nitride Nanopowder and Nanoplatelets

Boron nitride (BN) nanomaterials have been increasingly explored for potential applications in chemistry and biology fields (e.g., biomedical, pharmaceutical, and energy industries) due to their unique physico-chemical properties. However, their safe utilization requires a profound knowledge on their potential toxicological and environmental impact. To date, BN nanoparticles have been considered to have a high biocompatibility degree, but in some cases, contradictory results on their potential toxicity have been reported. Therefore, in the present study, we assessed two commercial 2D BN samples, namely BN-nanopowder (BN-PW) and BN-nanoplatelet (BN-PL), with the objective to identify whether distinct physico-chemical features may have an influence on the biological responses of exposed cellular models. Morphological, structural, and composition analyses showed that the most remarkable difference between both commercial samples was the diameter of their disk-like shape, which was of 200–300 nm for BN-PL and 100–150 nm for BN-PW. Their potential toxicity was investigated using adenocarcinomic human alveolar basal epithelial cells (A549 cells) and the unicellular fungus Saccharomycescerevisiae, as human and environmental eukaryotic models respectively, employing in vitro assays. In both cases, cellular viability assays and reactive oxygen species (ROS) determinations where performed. The impact of the selected nanomaterials in the viability of both unicellular models was very low, with only a slight reduction of S. cerevisiae colony forming units being observed after a long exposure period (24 h) to high concentrations (800 mg/L) of both nanomaterials. Similarly, BN-PW and BN-PL showed a low capacity to induce the formation of reactive oxygen species in the studied conditions. Even at the highest concentration and exposure times, no major cytotoxicity indicators were observed in human cells and yeast. The results obtained in the present study provide novel insights into the safety of 2D BN nanomaterials, indicating no significant differences in the toxicological potential of similar commercial products with a distinct lateral size, which showed to be safe products in the concentrations and exposure conditions tested

Evaluation of the effect of Loigolactobacillus coryniformis K8 CECT 5711 consumption in health care workers exposed to COVID-19

Following the spread of the SARS-CoV-2 coronavirus, an unprecedented burden has been placed on health care systems, with health care workers (HCWs) being most at risk of COVID-19 infection. The effect of the probiotic Loigolactobacillus coryniformis K8 CECT 5711 on frontline HCWs exposed to the virus was studied in a randomized, double-blind, placebo controlled trial. Parameters related to the incidence and severity of COVID-19 as well as the immune response and the side effects of the COVID-19 vaccine were evaluated. For 2 months, a group of 250 front-line HCWs over the age of 20 was randomly allocated to receive either L. coryniformis K8 or a placebo daily. SARS-CoV-2 infection incidence was verified via PCR or antigen test. In those volunteers who were vaccinated during the intervention, serum levels of specific IgG were analyzed at the end of the study. The incidence of COVID-19 infection was very low [IR (SD) = 0.016 (0.011)], and no significant difference was found between the groups [IRR (95% CI): 1.008 (0.140–7.268), p = 0.994]. For immune response analysis, the total sample was divided according to the days between the first dose and the antibody analysis (cutoff points were set at 56, 57–80 and 81 days). The specific IgG level decreased over time (p > 0.001). However, in the subgroup of subjects for whom more than 81 days had passed since they received the first dose, the specific IgG levels were significantly higher in the those that took the L. coryniformis K8 [7.12 (0.21)] than in the control group [6.48 (0.19)] (P = 0.040). Interestingly, the subjects who started probiotic consumption before the first dose reported significantly fewer side effects (of any kind) at the 1st dose of the vaccine (OR: 0.524, p = 0.043), specifically less arm pain (OR: 0.467, p = 0.017). In conclusion, the administration of L. coryniformis K8 CECT 5711 to HCWs helps to extend the immune protection generated by the COVID-19 vaccine over time.Regional Ministry of Economic Transformation, Industry, Knowledge and Universities and FEDER Funds (Project CV20_075443), Junta de Andalucia, Spai

Study of the behavior of biodegradable starch/polyvinyl alcohol/rosin blends

Biodegradable potato starch/PVA samples containing different concentrations of rosin were prepared by melt-mixing in order to study the enhancement of the properties of native starch films. Glycerol and polyvinyl alcohol (PVA) are commonly used as plasticizers of starch. Their relatively low molecular weight (compared with starch) contributes to a good processability. Rosin is a renewable product whose incorporation in the starch/PVA matrix induces processing aid and reinforcing effects. Its relatively high molecular weight might prevent its migration to the surface of the final product. Water content, solubility in water, mechanical properties, microstructure and dynamic mechanical analysis of the samples were studied. The addition of 8% rosin to starch/PVA blends led to tensile strength values higher than 10 MPa and elongation at break values close to 2000%, values comparable to those offered by conventional polymers used in food packaging, for example LDPE. Furthermore, starch compounds have low cost and high biodegradability.This work was partially supported from the European Commission (FEDER/ERDF) and the Spanish MINECO (Ref. CTQ2016-78246-R) and Generalitat Valenciana (Project PROMETEOII/2014/007). M.G. Montalbán acknowledges support from MINECO (Juan de la Cierva-Formación contract, Ref. FJCI-2016-28081)