Ecotoxicity assessment of dicationic versus monocationic ionic liquids as a more environmentally friendly alternative

One of the reasons why ionic liquids have received growing interest from researchers is their environmentally interesting characteristics, such as their negligible vapour pressure and their good chemical and thermal properties. In particular, dicationic ionic liquids whose thermal and electrochemical stability is higher than that of monocationic ionic liquids have begun to gain attention during recent years. In this work, monocationic and dicationic ionic liquids were synthesized, characterized and tested for their toxicity, which was assessed using the luminescent bacterium Vibrio fischeri. The results revealed that the toxicity of the ionic liquids mainly depends on the head groups and linkage chain length of their cationic structure. Introduction of a new cationic head decreased the EC50 (concentration which leads to 50% reduction in bioluminescence of the bacteria) of the ionic liquids. The results present a promising picture of dicationic ionic liquids as alternatives with lower environmental impact than their monocationic counterparts and underline the significance of designing particular structures for ionic liquids

Plant bioactive volatile products and their efficiency in aphid control

The “farm-to-fork strategy” of the European Union aims to reduce dependency on pesticides and towards increased use of low-risk products, such as those based on botanical extracts. A product based on the mixture of the five natural compounds selected for their repellent or insecticidal properties, namely citral, (E)-anethole, farnesol, cis-jasmone and lemon essential oil, was evaluated against Myzus persicae Sulzer (Hemiptera: Aphididae). Three formulations were prepared using various surfactants at different ratios: the first one with Tween80, the second one with soy (Glycine max (l.) Merr.) lecithin and the third one with soy lecithin and sunflower oil (Helianthus annuus L.). The oil-in-water nanoemulsions at 1% were tested in a laboratory study with Petri dishes using a computer-controlled spraying apparatus (equivalent application of 200 l/ha). The mean efficacy was 45%, 71% and 63%, respectively, with a least statistically significant difference (LSD) at 5% comparing the first two formulations. A field experiment (in two pepper, Capsicum anuum L., greenhouses) at Torreblanca Exp. Stat. in Murcia (Spain) followed in April 2020 in which a reduction in aphid populations only occurred by spraying the product formulated with soy lecithin. Phytotoxicity was also observed but was lower in the formulation that contained sunflower oil. Nanoemulsions were characterised using a Zetasizer, and a polydispersion of 2–3 populations of particles, ranging from 15 to 341 nm in size, was found with the Tween80 formulation and bigger sizes (250–438 nm) with the soy lecithin and sunflower oil formulation, which were more stable (Z potential = −28.15 mV). The application of ultrasounds reduces the Z-average to 100 nm in the mixture product with stability for at least 14 days. Another field experiment was repeated in February and April 2021. The plants were sprayed sequentially with the following: a) mixture product at 0.5% formulated with soy lecithin and sunflower oil, b) 3% cottonseed (Gopsyppium hirsutum L.) oil in 3% soap water (Feb.) or 1.5% cottonseed oil in 1.5% soap water (Apr.) and c) cis-jasmone at 0.25% formulated with Tween80. The treatment with the mixture of bioactive volatiles (a) was not more effective than that of the fixed seed oil (b). In February, the instantaneous population growth rate (ri) of aphid populations showed a significant reduction when the plants were sprayed with cottonseed oil. Further research is recommended for the formulation and application methods of the products being develope

Simulación de reactores autotérmicos. Parte I: Sin reacción en la zona de alimentación

Autothermic reactors are used normally in the industrial process but it is difficul to meet methods for their design. In this work is presented the methodology for that. It has been applied to two general casses with reaction, or no, in the feed zone. In both casses were planned the design equations, resolving their with computer programs that are the simulation digital models of the reactors on study.Siendo los reactores autotérmicos equipos habitualmente utilizados en procesos industriales es notoria la carencia de métodos que permitan afrontar su diseño. En el trabajo que aquí se presenta ha quedado resuelta la metodología de tal diseño que ha sido aplicada a los dos casos generales en los que alternativamente exista, o no, reacción en la zona de alimentación. En ambos casos se han planteado las ecuaciones de diseño, resuelto por medio de sendos programas de cálculo que, consiguientemente, configuran los correspondientes modelos digitales de simulación de los reactores en estudio

Simulación de un reactor-cambiador. Parte II

Como aplicación al tratamiento sobre simulación de un reactorcambiador expuesto en la PARTE I, se realiza a continuación un ejemplo de diseño para un sistema de reacciones simultáneas altamente exotérmicas, empleando agua como agente de enfriamiento. En base al tratamiento teórico expuesto en la PARTE I, como aplicación y comprobación de cuanto allí quedó discutido, se ha realizado el diseño de un reactor catalítico para la producción de óxido de etileno, diseño en el que han participado, durante el curso 1978-79, un grupo de alumnos (*) de la asignatura de Economía y Proyectos, cuya docencia imparte el Departamento de Química Técnica

Antibacterial effect of chitosan-gold nanoparticles and computational modeling of the interaction between chitosan and a lipid bilayer model

Pathogenic bacteria have the ability to develop antibiotic resistance mechanisms. Their action consists mainly in the production of bacterial enzymes that inactivate antibiotics or the appearance of modifications that prevent the arrival of the drug at the target point or the alteration of the target point itself, becoming a growing problem for health systems. Chitosan–gold nanoparticles (Cs-AuNPs) have been shown as effective bactericidal materials avoiding damage to human cells. In this work, Cs-AuNPs were synthesized using chitosan as the reducing agent, and a systematic analysis of the influence of the synthesis parameters on the size and zeta potential of the Cs-AuNPs and their UV-vis spectra was carried out. We used a simulation model to characterize the interaction of chitosan with bacterial membranes, using a symmetric charged bilayer and two different chitosan models with different degrees of the chitosan amine protonation as a function of pH, with the aim to elucidate the antibacterial mechanism involving the cell wall disruption. The Cs-AuNP antibacterial activity was evaluated to check the simulation model.This work was partially supported by the European Commission (FEDER/ERDF) and the Spanish MINECO (Refs. CTQ2017-87708-R, CTQ2017-83961-R and CTQ2017-92264-EXP) and the Seneca Foundation of Science and Technology of Murcia, Spain (Ref. 20977/PI/18). J.J.G.-C. and Marta G. Fuster acknowledges support from Spanish MINECO: “Ramon y Cajal” contract (#RyC-2014-14956) and FPI grant (PRE2018-086441), respectively. M.C. thanks the “Plan Propio de Investigación” from the Universidad de Córdoba and the “Programa Operativo de fondos FEDER Andalucía” for its financial support through both postdoctoral contracts (Modality 5.2.A). PIO CONICET-SECITI N°022, and CICITCA-UNSJ, Argentina for the financial support

Complex Polysaccharide-Based Nanocomposites for Oral Insulin Delivery

Polyelectrolyte nanocomposites rarely reach a stable state and aggregation often occurs. Here, we report the synthesis of nanocomposites for the oral delivery of insulin composed of alginate, dextran sulfate, poly-(ethylene glycol) 4000, poloxamer 188, chitosan, and bovine serum albumin. The nanocomposites were obtained by Ca2+-induced gelation of alginate followed by an electrostatic-interaction process among the polyelectrolytes. Chitosan seemed to be essential for the final size of the nanocomposites and there was an optimal content that led to the synthesis of nanocomposites of 400-600 nm hydrodynamic size. The enhanced stability of the synthesized nanocomposites was assessed with LUMiSizer after synthesis. Nanocomposite stability over time and under variations of ionic strength and pH were assessed with dynamic light scattering. The rounded shapes of nanocomposites were confirmed by scanning electron microscopy. After loading with insulin, analysis by HPLC revealed complete drug release under physiologically simulated conditions.This work has been partially supported from the European Commission (FEDER/ERDF) and the Spanish Ministry of Economy and Competitiveness (MINECO) (ref CTQ2017-87708-R) and by the Fundación Séneca del Centro de Coordinación de la Investigación de la Región de Murcia under projects 20977/PI/18 and by the Nils Coordinated Mobility under grant 012-ABEL-CM-2014A. Mar Collado-González acknowledges the fellowship for postdoctoral training (20381/PD/17) funded by the Consejería de Empleo, Universidades y Empresa de la Comunidad Autónoma de la Región de Murcia (CARM), through the Fundación Séneca de la Región de Murcia and for the support from the University of Murcia for stays abroad of young researchers and doctoral students in the action lines of Campus Mare Nostrum (R273/2016). Alessandra R. Freitas acknowledges support from the Brazilian National Council for Scientific and Technological Development (BolsistaCNPq-Brasil). Ana Cláudia Santos acknowledges support from the Portuguese Foundation for Science and Technology (FCT; SFRH/BD/109261/2015). Joana A. D. Sequeira acknowledges support from the Portuguese Foundation for Science and Technology and Tecnimede-S.A. for the grant (PD/BDE/135148/2017)

Complex Polysaccharide-Based Nanocomposites for Oral Insulin Delivery

Polyelectrolyte nanocomposites rarely reach a stable state and aggregation often occurs. Here, we report the synthesis of nanocomposites for the oral delivery of insulin composed of alginate, dextran sulfate, poly-(ethylene glycol) 4000, poloxamer 188, chitosan, and bovine serum albumin. The nanocomposites were obtained by Ca2+-induced gelation of alginate followed by an electrostatic-interaction process among the polyelectrolytes. Chitosan seemed to be essential for the final size of the nanocomposites and there was an optimal content that led to the synthesis of nanocomposites of 400–600 nm hydrodynamic size. The enhanced stability of the synthesized nanocomposites was assessed with LUMiSizer after synthesis. Nanocomposite stability over time and under variations of ionic strength and pH were assessed with dynamic light scattering. The rounded shapes of nanocomposites were confirmed by scanning electron microscopy. After loading with insulin, analysis by HPLC revealed complete drug release under physiologically simulated conditions