Perfectly Wetting Mixtures of Surfactants from Renewable Resources: The Interaction and Synergistic Effects on Adsorption and Micellization

This paper presents a study of the surface properties of mixtures of surfactants originating from renewable sources, i.e., alkylpolyglucoside (APG), ethoxylated fatty alcohol (AE), and sodium soap (Na soap). The main objective was to optimize the surfactant ratio which produces the highest wetting properties during the analysis of the solution of the individual surfactants, two- and three-component mixtures, and at different pH values. The results showed the existence of a synergistic effect in lowering the interfacial tension, critical micelle concentration and the formation of mixed micelles in selected solutions. We found that best wetting properties were measured for the binary AE:APG mixtures. It has been demonstrated that slightly lower contact angles values were observed on Teflon and glass surfaces for the AE:APG:soap mixtures but the results were obtained for higher concentration of the components. In addition, all studied solutions have very good surface properties in acidic, basic and neural media. However, the AE:soap (molar ratio of 1:2), AE:APG (2:1) and AE:APG:soap (1:1:1) compositions improved their wetting power at pH 7 on the aluminium and glass surfaces, as compared to solutions at other pH values tested (selected Θ values close to zero—perfectly wetting liquids). All described effects detected would allow less surfactant to be used to achieve the maximum capacity of washing, wetting or solubilizing while minimizing costs and demonstrating environmental care.     

Modeling and Numerical Simulation of Clays Cracking During Drying

During drying or desiccation of clay-type materials, some stresses appear. Usually they are compressional inside of the material and tensional close to the surface. If the tensional stresses exceed the material strength, the clay cracks. This article is devoted to the modeling and numerical simulation of this phenomenon. The proposed model consists of two parts. The mass transfer is described by a simple diffusion equation together with convective boundary conditions. In the mechanical part it is assumed that the clay is composed of small particles linked together by cohesive forces. These forces are described with the use of mesh models. Two models are proposed: elastic (mesh consists of springs) and viscoelastic one (mesh consists of Maxwell elements). Four types of clays were tested experimentally to obtain the model parameters. The tested materials were selected with respect to different mineralogical compositions that determine the water-bonding ability. Simulations of the convective drying of bricks made of these clays were performed. It was shown that the degree of cracking depends on the quartz content of the clay. The obtained results were compared with experimental ones and good agreement between simulations and experiment was obtained. Additionally, the inner forces caused by drying are analyzed and discussed in this work.     

Novel conventional and chelating anion exchange resins with amino ligands for sorption of silver

ABSTRACT

The polymeric resins containing diethylenetriamine, tetraethylenepentamine, 2-(diethylamino)ethanol, 1-methylimidazole, and 1,2-dimethylimidazole ligands have been synthesized from vinylbenzyl chloride-divinylbenzene copolymers and used in the removal of Ag(I) from chloride solution. The best Ag(I) sorption was reached in the case of 1-methylimidazole resin. Resins retain their capacity towards Ag(I) in five consecutive sorption/desorption cycles. The resins with imidazole ligands were highly selective for Ag(I) from synthetic chloride solution and they did not sorb chloride complexes of Cu(II). Additionally, the recovery of Ag(I) was tested from real chloride solution coming from leaching of the copper concentrate from Lubin Concentrator (KGHM Polska Mied? S.A.).     

Specific cationic photoinitiators for near UV and visible LEDs: Iodonium versus ferrocenium structures

Two iodonium salts based on a coumarin chromophore are investigated for polymerization upon light emitting diode irradiations (LEDs). They work as one‐component photoinitiators. They initiate the cationic polymerization of epoxides (under air) and vinylethers (laminate) upon exposure to violet LEDs (385 and 405 nm). Excellent polymerization profiles are recorded. Their efficiency is quite similar to that of a ferrocenium salt. Interpenetrating polymer networks can also be obtained through a concomitant cationic/radical photopolymerization of an epoxy/acrylate blend monomer. The light absorption properties of these new salts as well as the involved photochemical mechanisms are investigated for the first time through electron spin resonance, laser flash photolysis, steady state photolysis experiments. Molecular orbital calculations are also used to shed some light on the initiation mechanisms. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42759.     

Properties of Light MMCs Modified with Cordierite Synthesized from Fly Ash

This paper presents novel opportunities for management of fly ash by synthesizing the material into cordierite ceramics and using it as a reinforcing phase for light metal alloys. Metal matrix composites (based on magnesium alloy and aluminum alloy) were produced by squeeze casting. The magnesium matrix composites with a suitably selected reinforcing phase content (2 wt.%) exhibited much better strength properties than the unmodified alloy (AM60). It was also demonstrated that the wettability (or the lack thereof) in the metal-ceramic system is critical to successful production of the composites based on the AK7 alloy with cordierite. Light alloy matrix composites reinforced with cordierite ceramics particles are innovative materials that combine high strength with low weight, which may be a key factor of merit for numerous applications of the composite in various branches of industries.     

Existing Drugs Considered as Promising in COVID-19 Therapy

COVID-19 is a respiratory disease caused by newly discovered severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The disease at first was identified in the city of Wuhan, China in December 2019. Being a human infectious disease, it causes high fever, cough, breathing problems. In some cases it can be fatal, especially in people with comorbidities like heart or kidney problems and diabetes. The current COVID-19 treatment is based on symptomatic therapy, so finding an appropriate drug against COVID-19 remains an immediate and crucial target for the global scientific community. Two main processes are thought to be responsible for the COVID-19 pathogenesis. In the early stages of infection, disease is determined mainly by virus replication. In the later stages of infection, by an excessive immune/inflammatory response, leading to tissue damage. Therefore, the main treatment options are antiviral and immunomodulatory/anti-inflammatory agents. Many clinical trials have been conducted concerning the use of various drugs in COVID-19 therapy, and many are still ongoing. The majority of trials examine drug reposition (repurposing), which seems to be a good and effective option. Many drugs have been repurposed in COVID-19 therapy including remdesivir, favipiravir, tocilizumab and baricitinib. The aim of this review is to highlight (based on existing and accessible clinical evidence on ongoing trials) the current and available promising drugs for COVID-19 and outline their characteristics.     

Effects of SARS-CoV-2 Inflammation on Selected Organ Systems of the Human Body

Introduction and purpose of the study: SARS-CoV-2 virus does not only affect the respiratory system. It may cause damage to many organ systems with long-term effects. The latest scientific reports inform that this virus leaves a long-term trace in the nervous, circulatory, respiratory, urinary and reproductive systems. It manifests itself in disturbances in the functioning of the organs of these systems, causing serious health problems. The aim of the study was to review the latest research into the long-term effects of COVID-19 and determine how common these symptoms are and who is most at risk. Based on a literature review using the electronic scientific databases of PubMed and Web of Science on the long-term effects of SARS-CoV-2 infection, 88 studies were included in the analysis. The information contained in the analyzed literature shows that the SARS-CoV-2 virus can cause multi-organ damage, causing a number of long-term negative health complications. Conclusions: There is evidence that the virus can cause long-term complications lasting more than six months. They mainly concern disturbances in the functioning of the nervous, circulatory and respiratory systems. However, these studies are small or short-lasting, and many are speculative.     

The influence of protein–flavonoid interactions on protein digestibility in vitro and the antioxidant quality of breads enriched with onion skin

Different types of breads enriched with onion skin were studied. The objectives were twofold: to show and examine protein–phenolic interactions and to discuss results concerning phenolic content, antioxidant activity and protein digestibility in the light of in vitro bioaccessibility. Phenolic contents and antiradical abilities were linked with the level of onion skin supplement however, the amounts determined were significantly lower than expected. Fortification influenced protein digestibility (a reduction from 78.4% for control breads to 55% for breads with a 4% supplement). Electrophoretic and chromatographic studies showed the presence of indigestible protein–flavonoid complexes – with molecular weights about 25 kDa and 14.5 kDa; however, the reduction of free amino group levels and the increase in chromatogram areas suggest that flavonoids also bind to other bread proteins. The interaction of phenolics with proteins affects antioxidant efficacy and protein digestibility; thus, they have multiple effects on food quality and pro-health properties.     

The impact of glycated pea proteins on bacterial adhesion

Adhesion is one of the bacterial strategies indispensable for colonization of the small intestine. Food components reaching the small intestine, are not only digested and absorbed there, but may also influence the microorganisms colonizing the mentioned region. In this way, nutrients, particularly the ones the enzymatic degradation of which is hindered, acquire the ability to modify the adhesive potential of the autochthonic microorganisms. The glycated food proteins are noteworthy here for they often undergo relevant structural and functional alterations. Such proteins tend to display a lowered susceptibility to enzymatic degradation and thus may act as modulators of both metabolic activity and adhesive potential of bacteria adhered to the intestinal cells. For that reason, this study aimed at establishing the impact of the glycated pea proteins on adhesion of the bacteria from the genera: Lactobacillus, Enterococcus, and Escherichia, which are typical for the human small intestine.     

Study on the new bone cement based on calcium sulfate and Mg,CO3 doped hydroxyapatite

In order to improve some features of bone substitutes the new self-setting composite-type implant material based on Mg²⁺/CO₃^2? co-substituted hydroxyapatite (Mg-CHA) and calcium sulfate hemihydrate (CSH) was developed. Synthetic hydroxyapatites doped with small amounts of additives found in natural bone (e.g. Mg²⁺ and CO₃^2?) are regarded as promising components of calcium phosphate bone cements (CPCs). The CPCs, now available on the market, due to low resorption rate are too stable to permit material degradation and are slowly replaced by the newly formed bone. To improve cement resorption we used calcium sulfate which is a well-known biodegradable and biocompatible bone defect filler. Combining properties of Mg-CHA and CSH allowed developing a new, promising, easy shapeable implant material with high potential for bone regeneration.