Search

This work describes the use of the breath figure (BF) method for the fabrication of photoactive porous polymer films and the characterization of their responsive to photo stimulus. The films incorporate self-assembled photoactive polymers and ZnS nanoparticles (NPs). The effect of both components on the optical and morphological properties of the films were analyzed. Films with a hexagonally ordered pattern were obtained. The photoactive polymer was prepared by grafting the photochromic component 1-(2-hydroxyethyl)-3,3-dimethylindoline-6-nitrobenzopyran (SP) to polystyrene-block-polymethacrylic acid (PS-b-PMMA). ZnS NPs were incorporated into the polymer solution, and the films were prepared using spin-coating on glass substrates before subjecting them to the BF method. The hollow footprints were obtained before introducing the ZnS NPs in order to maintain the necessary conditions for hexagonal film growth. Accordingly, the SEM micrographs of the films prepared in the presence of ZnS NPs displayed a loss in the pore arrangement as a consequence of the interaction between SP moiety and NPs. The light-emitting properties of films were characterized by blue and violet colors when exposed to UV light under fluorescence. Progress in the field of breath-figure formation and its application, such as exemplified in this work, leads to functional structures with suitable applications in chemistry and materials science. It is expected that such microstructured polymeric films will have interesting applications in photonic and optoelectronic devices.

Nowadays, biomedical films containing drug carriers are preferred over conventional ones, since the protection of the injury and the therapy is joined within a single device. In the current work, we prepared polycaprolactone (PCL) composite films with β-cyclodextrin (βCD) or its epichlorohydrin crosslinked polymer (βCDP) as ibuprofen (Ibu) drug carrier. The composite films were prepared at different PCL/additive ratios (2, 5, 10 and 20 wt%). ATR-FTIR spectroscopy and water contact angle (WCA) measurements indicated a scarce presence of the additives on the surface. Cross-section scanning electron micrographs showed the presence of aggregates corresponding to βCD and βCDP in the inner regions of the films. The incorporation of βCD and βCDP into the PCL films did not affect their thermal properties as was determined from differential scanning calorimetry (DSC). PCL-films with 10 wt% of the inclusion complexes Ibu@βCD and Ibu@βCDP were prepared and the release studies were performed. At pH = 7.2, PCL-Ibu@βCDP composite film released 55% of Ibu within the first six hours; eight times the amount released by PCL-Ibu@βCD within the same time interval. A plausible mechanism for ibuprofen release is discussed based on the cross-section SEM micrographs of composite films.

Background Gamification is a promising field of research that can benefit education. In particular, it can benefit teaching programming to children. Emotional Learning Companions (ELCs) are interactive systems that dialogue with the students as well as provide them with emotional support. Intervention The design of ELCs was extended with gamification to teach programming to Primary Education children. Riddles, levels, badges, and a leader board with trophies among other traditional gamification elements were incorporated into the learning companion, as well as game mechanics, aesthetics and connection with the players (students) to increase their learning, motivation and satisfaction levels. Methods A pre-post test single group experimental research design was followed to test the proposal. In total, 137 students aged between 10 and 12 years used the gamified learning companion during an academic year in Ecuador. Results The results showed a significant increase in students’ learning scores as well as satisfaction and motivation levels above 90%. Conclusion Therefore, the conclusion is that gamifying ELCs to teach programming in Primary Education can improve students’ learning scores, satisfaction, and motivation levels.

Chromium (Cr) is used in many manufacturing processes, and its release into natural waters is a major environmental problem today. Low concentrations of Cr(VI) are toxic to human health and living organisms due to the carcinogenic and mutagenic nature of this mineral. This work examined the conversion of Cr(VI) to Cr(III) via electrochemical reduction using gold electrode in an acidic sodium alginate (SA) solution and subsequent removal of the produced Cr(III)-SA by the polymer-enhanced ultrafiltration (PEUF) technique. A solution of SA in nitric acid was used both as an electrolytic medium during the voltammetric measurements and bulk electrolysis and as an extracting agent during the PEUF technique. The electroanalysis of Cr(VI) was performed by linear sweep voltammetry in the presence of acidic SA solution to study its voltammetric behavior as a function of the Cr(VI) concentration, pH, presence of Cr(III), SA concentration and scan rate. In addition, the quantitative reduction of Cr(VI) to Cr(III) was studied through the bulk electrolysis technique. The results showed efficient reduction with well-defined peaks at approximately 0.3 V vs. Ag/AgCl, using a gold working electrode. As the pH increased, the reduction signal strongly decreased until its disappearance. The optimum SA concentration was 10 mmol/L, and it was observed that the presence of Cr(III) did not interfere in the Cr(VI) electroanalysis. Through the quantitative reduction by bulk electrolysis in the presence of acidic SA solution, it was possible to reduce all Cr(VI) to Cr(III) followed by its removal via PEUF.

The adulteration of extra virgin olive oils (EVOO) with virgin olive oils (VOO) previously subjected to a soft deodorization process (to eliminate organoleptic defects from these latter lower quality oils), in up to a 1:1 ratio, in order to be subsequently fraudulently distributed as genuine EVOO represent a serious problem of quality assurance for the olive sector still in force today [1]. The downward evolution of the comparative prices between VOO and EVOO, together with the difficulty of detecting the presence of deodorized oils in adulterated mixtures by means of the quality, purity and sensory analyses contemplated in the legislation, has awakened the ghost of this type of fraud among the main olive oil producing countries, with Spain at the head. To serve as a starting point for the development of a reliable methodology for the unequivocal detection of adulterations of EVOO with deodorized VOO, fraudulent mixtures are needed in order to characterize them in the search for differential quality markers. Likewise, generating fraudulent mixtures requires prior obtaining soft deodorized VOO to be used as adulterants. For obvious reasons, this type of oil is not directly available for purchase in the market so, in the present study, a lab-scale pilot plan was set up to carry out deodorization experiments. An experimental design methodology was used to optimize soft deodorization process conditions in the pilot plant throughout a two-stage procedure. In the first stage, optimization was tackled as a linear design problem considering temperature and deodorization time as the main process variables involved. The perceived intensities of the residual negative attributes that still retained the lampante olive oil used as raw material once deodorized under a certain set of operating conditions were evaluated by an expert sensory panel. A two-level full factorial design with two factors was selected for the analyzed sensory defects (vinegary, fusty/muddy sediment, metallic, mould/humidity and rancid). Design resolution provided a mathematical model that allowed to correlate the process variables with the response variable studied, i.e., to predicted the value of the response variable (degree of organoleptic defect removed) as a function of deodorization conditions. Then, in a second stage, the steepest ascent method was applied to establish optimal conditions for VOO deodorization processes. Optimal deodorization conditions were selected as those for which all undesirable organoleptic properties were entirely removed. For each experiment carried out during optimization, a double sensory evaluation was performed: the first one served to determine the percentage of defect removed immediately after deodorization was completed, and the second one to assess oil stability over time.The optimally deodorized lampante oil obtained was subsequently used to generate adulterated blends with both a recently harvested (fresh) EVOO (arbequina) and a two-year-old EVOO (oliberus) in the range 0-50%. All adulterated EVOO samples thus prepared were submitted to the regulatory analyses required: acidity, peroxide value, UV spectrophotometric measurements and organoleptic evaluation [2-3]. A detailed analysis of the values obtained for the various quality and purity parameters assessed in the set of EVOO adulterated with deodorized VOO allowed to verify that these fraudulent oils were able to evade their detection in all the adulteration range studied, although they were not able to preserve their stability over time. The results of this study confirmed the need for developing and validating new analytical methodologies capable of efficiently detecting and quantifying these adulterations in routine controls at any point of the complex food chain in order to avoid the sale and consumption of products of inferior quality to the one declared.

In the present work, three hydrogels of poly(2-hydroxyethyl methacrylate-co-itaconic acid), p(HEMA-co-IA), poly(2-hydroxyethyl methacrylate-co-acrylic acid), p(HEMA-co-AA) and poly(2-hydroxyethyl methacrylate-co-(1-vinyl-2-pyrrolidone)), p(HEMA-co-NVP) were prepared by free radical polymerization in aqueous solution (1:1 monomer mole ratio) using ammonium persulfate as initiator and N,N′-methylenebisacrylamide as crosslinking agent at two different amount (0.3 and 0.9 mol%). The obtained hydrogels were characterized by Fourier transform infrared spectroscopy (FT-IR), which allowed to verify the structural composition. Thermal analysis of the hydrogels was carried out by thermogravimetric analysis (TGA). In addition, hydration capacity (U%) was studied at different experimental conditions such as: time, pH, concentrations of interfering salts (KCl, NaCl and LiCl). The results showed a good polymerization yield (95%). FTIR characterization shows the absorption bands of the functional groups of copolymers. TGA exhibited the characteristic thermal stability of this type of hydrogels. The presence of comonomer AI, AA or NVP in copolymer determine the thermal behavior. Hydration experiments revealed a higher U% in copolymer containing more carboxylic acid groups. The maximum U% values in water were 400% and 250% for p(HEMA-co-AI) and p(HEMA-co-AA), respectively. For P(HEMA-co-NVP) a maximum of U% value was only 74% in water. The effect of interferent salts affects the hydration capacity decreasing U% when the concentration of salts increase.

High-performance catalysts and photovoltaics form key components for various technological applications. Because catalytic and photovoltaic reactions occur at the interfaces between reactants and surfaces, the chemical, physical, and structural properties of interfaces have been the focus of many studies. One route towards the improvement and optimization of such interfaces is the preparation of microporous materials from amphiphilic copolymers, which can also be surface coated with inorganic nanoparticles to obtain different properties. In this work, we have prepared microporous hybrid films with fluorescent properties from amphiphilic block copolymers surface coated with ZnS (NPs) based on the breath figure (BF) mechanism, keeping constant the concentration of ZnS NPs, solvent, humidity and substrates. The morphological and optical properties were investigated by microscopic and optical characterization techniques. As a result, the fabrication method facilitates the preparation of fluorescent porous films with varying morphological properties (shapes and diameter pore). The hybrid porous films containing polystyrene-b-polyacrylic acid, polystyrene-b-polyitaconic acid and polystyrene-b-polydialylmalonic acid were obtained with an average pore size of 0.57 ± 0.04 μm, 0.78 ± 0.03 μm and 1.50 ± 0.04 μm, respectively. An increase in the water contact angle (WCA) was observed in the block copolymer porous films after functional process with ZnS (NPs).

Poly(ethylene glycol) diacrylate (PEGDA) of different molecular weights (Mn = 575 and 700) was used as crosslinking agent for the photopolymerization of 2-hydroxyethyl methacrylate (HEMA) in order to obtain HEMA/PEGDA-based hydrogels. Composites were synthesized in situ employing a new methodology that implies the addition of different quantities of silver nitrate aqueous solution to the monomer mixture with the finality to obtain hydrogels with different silver nanoparticles’ spatial density and distribution. Samples were characterized by thermal, optical, spectroscopic and structural/morphological methods. Thermal studies showed that the increase of PEGDA molecular weight and the AgNO3 concentration in the reaction mixture enhance the glass transition temperature and the thermal stability of the composites. This behavior could be related to the silver coordination with the polymer network. Infrared spectroscopy with Fourier transform and Raman analyses were realized in order to corroborate the sample chemical structure by the identification of specific functional groups. Surface hydrogel morphology was visualized with scanning electron microscopy analysis, detecting a homogeneous micro-porous surface for the samples obtained from high molecular weight PEGDA. Presence of silver nanoparticles was established by X-ray fluorescence spectroscopy and UV/Vis methods. In this last case, the characteristic silver nanoparticle plasmon was observed. Using Transmission Electron Microscopy it was possible to visualize a homogeneous spatial distribution of spherical silver nanoparticles with very narrow diameter distribution that rounds about 14–21 ± 5 nm. In general, the silver nanoparticle presence in the compounds enhances considerably their thermal/morphological characteristics. Keywords: Silver nanoparticles, HEMA/PEGDA hydrogel, Thermal properties, Crosslinking agent

In this study, we report a low cost, fast and unexplored electrochemical synthesis strategy of copper oxide nanoneedles films as well as their morphological and chemical characterization. The nanostructured films were prepared using electrochemical anodization in alkaline electrolyte solutions of ethylene glycol, water and fluoride ions. The film morphology shows nanoneedle-shaped structures, with lengths up to 1–2 μm, meanwhile, high-resolution X-ray photoelectron spectroscopy (HRXPS) and spectroscopy Raman analyses indicate that a mixture of Cu(II) and Cu(I) oxides, or only Cu(I) oxide, is obtained as the percentage of water in the electrolyte solution decreases. A preliminary study was also carried out for the photocatalytic degradation of the methylene blue (MB) dye under irradiation with simulated sunlight in the presence of the nanoneedles obtained, presenting a maximum degradation value of 88% of MB and, thus, demonstrating the potential characteristics of the material investigated in the degradation of organic dyes.

ECMO is an advanced technique of ventilatory and circulatory support. However, it can be associated with neurological complications. The proposal is to describe the clinical characteristics and neurological complications profile in patients under ECMO support.To descriptive a case series study. A descriptive and retrospective analysis and a bivariate analysis were performed in order to compare the main clinical variables of interest.136 adults undergoing ECMO with an average age of 51 years (17-78) were evaluated. Neurological complications were observed in 51 patients (37.5%), corresponding to stroke 22 (16.17%), hypoxic encephalopathy 13 (9.5 %), cerebral hemorrhage (HIC) in 12 (8.8%) and subarachnoid hemorrhage (HSA) in 4 patients (2.9%). Seven (13.7%) of patients with neurological complications had seizures. Neurological complications occurred in 23.53% in venovenous ECMO and in 76.47% with veno-arterial ECMO (p = 0.86). The overall mortality was 51.47% (70/136) for all patients in ECMO and 64.7% (33/51) for the population with neurological complications. The mortality in stroke was 54.5% (12/22), 91.6% (11/12) in HIC and 100% (4) in HSA (p = 0.03). Mortality was higher in veno-arterial ECMO (77.14%) versus venous-venous ECMO (22.86% of total), (p = 0.015).ECMO is a useful therapeutic tool in cases of high clinical severity. In our study, we identified a high rate of neurological complications that contribute to associated morbidity and mortality. Early neuroimaging studies in these cases could allow early detection of these complications.Complicaciones neurológicas asociadas al tratamiento con oxigenación por membrana extracorpórea (ECMO) en pacientes adultos. Estudio de una serie de casos.Introducción. La ECMO es una técnica avanzada de soporte ventilatorio y circulatorio. Sin embargo, puede asociarse a complicaciones neurológicas. Se propone describir las características clínicas y el perfil de las complicaciones neurológicas en pacientes sometidos a ECMO. Pacientes y métodos. Estudio descriptivo retrospectivo de una serie de casos. Se realizó un análisis descriptivo y un análisis bivariado con la finalidad de comparar las principales variables clínicas de interés. Resultados. Se evaluó a 136 adultos sometidos a ECMO con edad promedio de 51 años (17-78). Las complicaciones neurológicas se presentaron en 51 pacientes (37,5%), de los cuales correspondieron a ictus 22 (16,17%); a encefalopatía hipóxica, 13 (9,5%); a hemorragia intracerebral (HIC), 12 (8,8%), y a hemorragia subaracnoidea (HSA), cuatro (2,9%). Siete (13,7%) de los pacientes con complicaciones neurológicas presentaron crisis epilépticas. Las complicaciones neurológicas se presentaron en 12 pacientes (23,53%) con la ECMO venovenosa y en 39 (76,47%) con la ECMO venoarterial (p = 0,86). La mortalidad global fue del 51,47% (70/136 pacientes) y del 64,7% (33/51) para la población con complicaciones neurológicas. La mortalidad en el ictus fue del 54,5% (12/22), del 91,6% (11/12) en la HIC y del 100% (4/4) en la HSA (p = 0,03). La mortalidad en la ECMO venoarterial fue del 77,14%, frente al 22,86% de la de la ECMO venovenosa (p = 0,015). Conclusiones. La ECMO es una herramienta terapéutica útil en casos de elevada gravedad clínica. En nuestro estudio, identificamos una elevada tasa de complicaciones neurológicas que contribuyen a la morbimortalidad asociada. La realización temprana de estudios de neuroimagen en estos casos podría permitir una detección temprana de estas complicaciones.

In the present research, nanocomposites based on copper (I) oxide poly(1-vinyl-2—pyrolidone-co-itaconic acid) nanostructures (Cu2O/p(NVP-co-AI)) were synthesized by the electrodeposition method using the copolymer p(NVP-co-AI) as a stabilizing agent in the reduction of Cu+2 to Cu+. The chemical and physical properties of the nanostructures were characterized by techniques such as scanning electron microscopy, infrared (IR) spectroscopy, Raman and ultraviolet-visible spectrophotometry. The obtained nanostructures are mainly a mixture of agglomerated nanospheres with a diameter of approximately 78 to 91 nm, with an alternation of nanolaminar structures, composed of copper (I) oxide species. In the case of the Cu2O/p(NVP-co-AI) nanocomposite, it was observed a decrease in the carbon-oxygen vibration links of the carbonyl groups in IR intensity for the polymer when it was dissolved in the electrolytic solution, which indicates that interactions are produced by the carbonyl groups with the Cu2O species. In addition, bandgap values of 1.80 and 1.63 eV were estimated by the Kubelka–Munk method for Cu2O and Cu2O/p(NVP-co-AI) samples, respectively.

Hallazgos preliminares del ensayo clínico multicéntrico de evaluación de la seguridad de la aspiración supraglótica continua

Electrospun meshes (EM) composed of natural and synthetic polymers with randomly or aligned fibers orientations containing 0.5% or 1% of thermally reduced graphene oxide (TrGO) were prepared by electrospinning (ES), and their hyperthermia properties were evaluated. EM loaded with and without TrGO were irradiated using near infrared radiation (NIR) at 808 nm by varying the distance and electric potential recorded at 30 s. Morphological, spectroscopic, and thermal aspects of EM samples were analyzed by using SEM-EDS, Raman and X-ray photoelectron (XPS) spectroscopies, X-ray diffraction (XRD), and NIR radiation response. We found that the composite EM made of polyvinyl alcohol (PVA), natural rubber (NR), and arabic gum (AG) containing TrGO showed improved hyperthermia properties compared to EM without TrGO, reaching an average temperature range of 42&ndash, 52 &deg, C. We also found that the distribution of TrGO in the EM depends on the orientation of the fibers. These results allow infering that EM loaded with TrGO as a NIR-active thermal inducer could be an excellent candidate for hyperthermia applications in photothermal therapy.

In the present work, new biocomposite hydrogels were prepared based on the vinyl monomer 2-methacroyloxyethyltrimethyl ammonium chloride (ClAETA) in the presence of nanofibrillated cellulose (CNF) for the removal of the emerging contaminant nafcillin sodium monohydrate (NFX). The hydrogels were synthesized via free radicals, with the amount of CNF varied, and characterized by fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA), and scanning electron microscope (SEM) techniques. The capacity to absorb water and to remove NFX was determined through batch studies. It was observed that the presence of CNF significantly promotes both properties, with a hydration capacity of 2100% and an NFX adsorption capacity of 45 mg g−1 in P(ClAETA)1-12-2%CNF (pH 6, 0.01 g of adsorbent, initial concentration of NFX 200 mg g−1). The conformational study showed that in the most stable conformation, CNF avoids direct interaction with the NFX molecule. Herein, the main interactions are predominantly dominated by weak interactions such as London dispersion and electrostatic interactions between charged groups. Molecular dynamics simulations distinguish the existence of π-π stacking interactions between aromatic rings from NFX in the polymer + NFX system. Contact interactions were qualitatively and quantitatively characterized by the NCI index and the IGM analysis.