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We analyze the axiomatic strength of the following theorem due to Rival and Sands [28] in the style of reverse mathematics. Every infinite partial order P of finite width contains an infinite chain C such that every element of P is either comparable with no element of C or with infinitely many elements of C. Our main results are the following. The Rival–Sands theorem for infinite partial orders of arbitrary finite width is equivalent to $\mathsf {I}\Sigma ^0_{2} + \mathsf {ADS}$ over $\mathsf {RCA}_0$ . For each fixed $k \geq 3$ , the Rival–Sands theorem for infinite partial orders of width $\leq \!k$ is equivalent to $\mathsf {ADS}$ over $\mathsf {RCA}_0$ . The Rival–Sands theorem for infinite partial orders that are decomposable into the union of two chains is equivalent to $\mathsf {SADS}$ over $\mathsf {RCA}_0$ . Here $\mathsf {RCA}_0$ denotes the recursive comprehension axiomatic system, $\mathsf {I}\Sigma ^0_{2}$ denotes the $\Sigma ^0_2$ induction scheme, $\mathsf {ADS}$ denotes the ascending/descending sequence principle, and $\mathsf {SADS}$ denotes the stable ascending/descending sequence principle. To the best of our knowledge, these versions of the Rival–Sands theorem for partial orders are the first examples of theorems from the general mathematics literature whose strength is exactly characterized by $\mathsf {I}\Sigma ^0_{2} + \mathsf {ADS}$ , by $\mathsf {ADS}$ , and by $\mathsf {SADS}$ . Furthermore, we give a new purely combinatorial result by extending the Rival–Sands theorem to infinite partial orders that do not have infinite antichains, and we show that this extension is equivalent to arithmetical comprehension over $\mathsf {RCA}_0$ .

Propranolol hydrochloride can be considered a persistent and bioaccumulative pharmaceutical in the environment. This drug and its by-products are potentially toxic and have adverse effects, since these compounds have been associated with endocrine-disrupting effects, reproductive deficiencies, embryo abnormalities and pericardial oedema. TiO2–La 0.05%–carboxymethyl-β-cyclodextrin (CMCD) nanoparticles were successfully prepared by a simple two-step method, which consists of sonification and functionalization. The characterization analyses reveal that lanthanum is dispersed on the semiconductor surface, probably forming Ti–O–La bonds, which can induce oxygen vacancies and surface defects that effectively restrain the recombination of photogenerated electron/holes pairs. The efficiency of TiO2–La 0.05%–CMCD samples in degradation of propranolol under UV-light irradiation is higher than that of pristine TiO2 within 20 min reaction, probably due to complex formation between the β-blocker and the oligosaccharide, which allows us to propose a photocatalytic mechanism based on the formation of intermediates and competition of these compounds to the radicals and CMCD cavities.

This work aims to synthesize neryl acetate from the nerol esterification reaction with acetic anhydride through heterogeneous catalysis using the ion exchange resin Lewatit® GF 101. The reaction was monitored by gas chromatography and the neryl acetate chemical structure was confirmed by mass spectrometry and nuclear magnetic resonance spectroscopy. The variables effect on the neryl acetate synthesis was evaluated from an experimental design analysis. The reaction showed the highest combined values for nerol conversion (98.11%) and neryl acetate selectivity (86.10%) at 30 min within optimal experimental conditions of temperature at 40 °C, catalyst content at 7% wt, molar ratio at 1:4 (nerol: acetic anhydride), agitation speed at 250 rpm and nerol content at 3 mmol. The complete nerol conversion was achieved at 40 min with 82.34% selectivity. The reaction rate was controlled only by the nerol decay, an expected behavior due to the excess of acetic anhydride used. In addition, the value obtained for the main reaction kinetic constant found by a pseudo-homogeneous model was 6 times greater than that of the parallel reaction. The catalyst reuse was investigated and after 3 cycles a high conversion (96.68%) and selectivity (83.78%) were observed indicating a low loss of the catalytic activity.

The demand for food has intensified production in agricultural areas and stimulated the use of nanotechnology to develop new inputs, especially nanoparticle materials. In this new context, predicting the impact of using nanoparticles on non-target organisms becomes a necessary measure. The aim of this study was to evaluate the ecotoxicological potential of magnesium (Mg

In this study, the influence of the synthesis parameters on the microstructural properties of nanoparticles of magnesium oxide coated with carbon was investigated. The nanostructures were produced in a one-step synthesis procedure, following a sol-gel method, and the effects of the molar ratio between magnesium nitrate and glucose, the temperature and the dripping time on the morphology of the nanostructures formed were analyzed. The results indicate that an increase in carbon concentration, synthesis temperature around 60 °C and 4 h of dripping time favor the formation of small agglomerates of nanoparticles with greater carbon coating homogeneity. In general, high synthesis temperatures favor the kinetic aspects of crystallization and produce nanostructures with a larger crystallite size. On the other hand, altering the dripping time was not efficient in changing the morphology of the nanostructures obtained. In addition, increasing the carbon concentration favors the formation of structures with small surface area and pore volume.

The objective of this study was to obtain and characterize Nerol essential oil encapsulated in PCL. The miniemulsion and solvent evaporation method was used, resulting in PCL-Nerol capsules bonded by a physical interaction, with a dispersity index of 0.101, a particle size of 0.14 µm, and an encapsulation efficiency of 94.27%. In addition, the temperature at which the oil degraded could be observed to increase by 100 °C when it is encapsulated in PCL, revealing this polymer's capacity in working as an encapsulating agent. The PCL-Nerol capsules in suspension proved to be stable for 60 days regarding the pH of the suspensions, mean particle size, dispersity index, zeta potential and the encapsulation efficiency, not presenting clusters and flocculation. The results are considered satisfactory and important for the future industrial applications of the obtained microparticles.

Geraniol has been an attractive compound for food preservation due to its antibacterial and antifungal actions. The main objective of this study was to produce and characterize polycaprolactone (PCL) capsules for the protection of the encapsulated geraniol essential oil. The encapsulation was carried out using a miniemulsion polymerization technique with an efficiency of (95.44 ± 0.60%). The capsules were obtained with a mean size of 148 nm and with a polydispersity index of 0.12. Transmission electron microscopy results confirmed the formation of spherical capsules of PCL coating the geraniol. From the analysis of thermogravimetry, it was possible to prove the thermal protection of geraniol by PCL coating since the release of the encapsulated geraniol occurred with temperatures 100 °C higher than the volatilization temperature of the natural compound. An important observation was that the microcapsules of PCL-geraniol immersed in aqueous suspensions at 4 °C showed good stability over 60 days.

Propranolol (PRO) hydrochloride is one of the most commonly used β-blockers for cardiovascular diseases that is frequently detected in aquatic environment. Photocatalytic removal of propranolol using an efficient UV and visible light responsive neodymium (Nd)-modified photocatalyst has been investigated. Nd–TiO2 nanoparticles were synthesized by a simple ultrasonic method with Nd-modified in the range of 0–1.0 mol% to evaluate the effects of Nd3+ content in crystal structure and photocatalytic activity. The TiO2–Nd 0.10% sample was the most efficient photocatalyst to degrade PRO with 95% and 90% degradation after 60 min under UV and visible light radiation, respectively. The characterization analysis revealed that neodymium is dispersed on the surface semiconductor, where probably forming Ti–O–Nd bonds, which can induce oxygen vacancies and surface defects. The effective separation of the photogenerated electrons and holes was regarded as the main reason for the high photocatalytic activity. The effective separation of the photogenerated electrons and holes was regarded as the main reason for the high photocatalytic activity.

This manuscript presents an experimental and modeling approach in order to characterize the stiffness loss of bioabsorbable polymer filaments due to hydrolysis. In this regard, bioabsorbable suture yarns (poly(lactic-co-glycolic) acid—PLGA) were chosen as a representative material for the present investigation. The observed mechanical response was characterized by means of a thermodynamically consistent constitutive variational framework. Usually, two different damage variables are assumed to take place in this class of materials: a hydrolytic damage (long-term degradation) and a strain-driven damage (short-term degradation). This work concerns the proposition of a constitutive model that only considers the hydrolytic damage, in which a specific strain energy and a proper dissipation damage potential were tailored to model the tested material. A nonlinear curve fitting procedure based on Particle Swarm Optimization was performed to identify the constitutive parameters. A set of numerical simulations demonstrates the effectiveness of the proposed constitutive model to predict damage-induced creep and damage-induced stress relaxation, behaviors that can be used as design criteria in absorbable implants. The main achieved results show that the proposed constitutive approach leads to a simple but effective model capable to drive the first steps in the design of absorbable biomedical devices. The present variational framework can be extended to study the constitutive response of other bioabsorbable polymers, accounting for viscous and/or plastic behaviors.

The present work concerns to investigate the microbiological, thermal and mechanical behavior of cellulose acetate films obtained with addition of 0.5 % (v/v) and 1.0 % (v/v) of geranyl acetate by the casting technique. The antimicrobial activities of the polymeric films were assessed against Staphylococcus aureus and Escherichia coli bacteria and against Aspergillus flavus fungal. The achieved results show that the films presented antibacterial and antifungal activities. Moreover, the incorporation of the geranyl acetate in the polymeric films was confirmed by FTIR and TGA technique, while DSC analysis pointed out the compatibility between the geranyl acetate and cellulose acetate. The addition of the geranyl acetate did not modify the mechanical behavior of the cellulose acetate films concerning stiffness and tensile strength. These results suggest that this new material is promising for future applications in biomedical devices and food packaging.

Miniemulsion polymerization process is a very versatile technique used for the polymeric encapsulation of the many essential oils. In this process some surfactant compounds are used to define the capsules characteristics, as an example the Sodium Lauryl Sulphate (SLS) that is one of the most used surfactants. But, after the miniemulsion polymerization synthesis the residual amount of SLS can manifest an antimicrobial action that can improve or to prejudice the final properties of the encapsulated products, depending of its percentual concentrations. In this sense, the objective of this work was to evaluate the antimicrobial activity of polycaprolactone (PCL) capsules synthesized with different residual concentrations of the SLS surfactant after the miniemulsion polymerization processes. The antimicrobial evaluations demonstrated from solid media diffusion test that the PCL microcapsules are microbiologically inactive for the bacteria Staphylococcus aureus and Escherichia coli when are synthetized with residual concentrations of SLS below 0.0125%. The minimum inhibitory concentration (MIC) of residual SLS for the bacteria Staphylococcus aureus is 0.0146% and for the bacteria Escherichia coli the complete bacterial inhibition not was detected at the maximum residual concentration studied of 0.1167%.

The increase in researches related to nanomaterials has provided innovation and enhancement of the properties of innumerous materials. Among the materials frequently studied, magnesium oxide can be cited because of its many industrial applications, mainly in the chemical and electronics sectors. Magnesium oxide nanoparticles, as well as other nanomaterials, can be produced by several routes of synthesis, and the characteristics of the route chosen may change the microstructure and properties of the nanoparticles. However, despite the general consensus that the synthesis variables affect the characteristics and properties of the nanoparticles, much still needs to be studied. Among these variables, the reactive environment is one of the factors that influence considerably and about which there are still few studies. In this work, it was evaluated, using the sol-gel synthesis method, how the modification of the solvent, water or ethyl alcohol, affects the morphology and purity of the magnesium oxide nanoparticles, as well as the yield of the synthesis reactions. The nanoparticles were characterized by XRD, surface area analysis via BET, FEG-MEV and EDS. The results indicated that the nanoparticles obtained by route using ethyl alcohol as solvent have a larger crystallite and particle size, besides the synthesis reactions have a higher yield. In addition, by the analysis of surface area and pore volume, they present a lower surface area and lower pore volume, in relation to the route that uses water as solvent. Thus, it was possible to conclude that altering the solvent of the reaction, even if all other synthesis conditions are maintained, significant modifications are observed in the morphology of the magnesium oxide nanoparticles and also in the reaction yield.

The objective of this study was to evaluate the effect of treatment with simple or coated nanoparticle and concentrations on storage time and the germination parameters in corn seeds. The treatments composed of three magnesium sources, magnesium oxide nanoparticles and nanoparticles in the form of (MgO NPs), magnesium carbon oxide core-shell nanoparticles (MgO@C NPs) and magnesium nitrate [Mg(NO3)2]. Six concentrations 0 (control) 37.5, 75, 150, 300 and 600 mg.L-1 were applied. The treated seeds were submitted to germination tests, after different storage times: 0, 30, 60, 90 and 150 days and then the normal and abnormal seedlings were evaluated. The results indicate that the treatment process with simple or coated nanoparticles with optimal concentration value, between 75 and 150 mg.L-1 of Mg, can approximately increase 6% of normal seedlings in conjunction with the storage time (90-150 days). The exposure of the seeds to magnesium nitrate resulted in less normal plants, possibly due to the saline and toxic effect of this source. The best germination performance of seeds pretreated with simple or coated nanoparticles can be achieved at the concentration of 75 mg.L-1 and for the storage time of 150 days. There might be some negative effect for magnesium nitrate depending on concentration and storage time.

A silicon/polyaniline/horseradish peroxidase enzyme (n-Si/PANI/HRP) electrode was obtained by potentiostatic electrodeposition processes. PANI thin films were electropolymerized on a silicon substrate at different electric potentials, and an HRP enzyme was electrodeposited on the best PANI thin film. The best PANI thin film was obtained under electrodeposition conditions of + 1.00 V (vs. Ag/AgCl) and 900 s, and the immobilization of the HRP enzyme was performed at an electric potential of − 0.50 V (vs. Ag/AgCl). The n-Si/PANI- and n-Si/PANI/HRP electrodes were characterized using scanning electron microscopy and atomic force microscopy. The detection capacity of the glyphosate of the n-Si/PANI/HRP electrode with the best morphological characteristics was evaluated according to the electric current density responses from the oxidation of hydroquinone molecules in a solution containing different concentrations of glyphosate. The detection was performed because of the inhibition of the HRP enzyme activity by the glyphosate molecules in the solutions with a lower concentration limit of 5.44 μg L−1 over an electric potential range of + 0.65 to + 1.15 V (vs. Ag/AgCl).

A qualidade da água vem sendo uma preocupação crescente devido principalmente ao aparecimento de contaminantes emergentes nas águas de consumo, o que tem provocado pesquisas de diferentes tecnologias e processos para seu tratamento. Portanto o objetivo deste trabalho foi analisar a adsorção da tetraciclina utilizando uma matriz de poliuretano expandido com carvão ativado obtido a partir da casa de banana. O carvão ativado foi obtido pelo processo químico e físico e a matriz foi desenvolvida com diferentes frações do carvão. Com as matrizes, foi realizado um teste de adsorção com concentrações diferentes de Tetraciclina (10 mg/L e 30 mg/L). Através dos resultados obteve-se uma eficiência de remoção de tetraciclina de 22,9% para a concentração de 10 mg/L e 21,4% para a concentração de 30 mg/L para a matriz de 10% de carvão. Uma análise da eficiência do carvão ativado foi realizada, e obteve-se uma eficiência de aproximadamente de 98% para ambas as concentrações de tetraciclina estudas. Apesar da matriz não apresentar resultados satisfatórios na adsorção, a casca de banana provou ser um bom meio de obtenção de carvão ativado alternativo, utilizando-se de um resíduo industrial para adsorção de fármacos, como a tetraciclina.

In this work, the feasibility of obtaining Alite and Belite with possible applications in the cement industry from the primary sludge generated by a paper recycling industry in the State of Santa Catarina, Brazil was studied. The effect of the heat treatment on the physical and chemical properties of the primary sludge was studied, when treated at 800 °C, 875 °C and 950 °C, and defined by studies using the dilatometry technique. The treated sludge at these temperatures was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), thermal dilatometry (TD), X-ray fluorescence spectroscopy (XRF), surface analysis by the method of Brunauer, Emmett, Teller (BET), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The results showed the appearance of the Alite and Belite phases with different proportions, depending on the temperatures used during the heat treatment processes and with sufficient quality for application in the cement industry, since the optimal condition to obtain Alite is the heat treatment at 950 °C. In addition, the temperatures used were lower than those used in the conventional processes of Alite and Belite.

Sodium montmorillonite organically modified by octadecylammonium (Np-Clay) and zinc oxide nanoparticles (Np-ZnO) were incorporated into chitosan (C) matrix in different proportions to evaluate its mechanical properties and antimicrobial activities. The composites were obtained by polymer intercalation method in solution using acetic acid (1% v/v) as solvent. The functional groups, thermic behavior and surface morphology of the chitosan film and of the composites prepared with different percentages of Np-Clay and Np-ZnO were characterized through Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The results showed that a combined effect of clay and zinc oxide increases significantly the mechanical properties of pure chitosan. FTIR results confirmed good compatibility among functional groups of chitosan, montmorillonite/metallic oxides. The Np-ZnO distribution became more uniform in chitosan films when the Np-clay was incorporated, thus, the Np-Clay compatibilizes the Np-ZnO with the chitosan and the mechanical properties improved and without affecting the antimicrobial activity of the films. The thermal degradation temperature of the chitosan did not change significantly with the addition of Np-Clay, but changes significantly with Np-ZnO addition. In antimicrobial test was found that the chitosan and Np-ZnO showed a synergistic effect against to Escherichia coli and Staphylococcus aureus. The addition of Np-ZnO and C-Clay in chitosan resulted in enhancement of mechanical and antimicrobial properties, turning this material prospective for food packaging applications.

A nanocomposite composed of organophilic bentonite (OB) with geranyl acetate (GA) was prepared on a shaker for 1 hours, 180 rpm and room temperature, being subsequently dried an oven at 90 ºC±2 ºC during 48 hours. This material was then characterized for its antibacterial against Staphylococcus aureus and Escherichia coli and antifungal activity against Aspergillus flavus and Aspergillus niger, respectively. Moreover, the adsorption capacity of OB and OB/GA was evaluated using Aflatoxin B1 in the concentration of 107 µg∙L-1. After 17 h, the composite removed a significant amount of mycotoxin, being below 20 µg∙L-1. The results showed that this composite has a good adsorption capacity, can be effective in the removal of mycotoxin in aqueous media and excellent antibacterial and antifungal activity. Se preparó un nanocompuesto a base de bentonita organófila (BO) y acetato de geranilo (AG) en agitador durante 1 hora, 180 rpm y temperatura ambiente, siendo posteriormente secado en estufa a 90 ºC±2 ºC durante 48 horas. Luego, este material se caracterizó por su actividad antibacteriana contra Staphylococcus aureus y Escherichia coli y antifúngica contra Aspergillus flavus y Aspergillus niger, respectivamente. Además, se evaluó la capacidad de adsorción de BO y BO/AG utilizando Aflatoxina B1 en la concentración de 107 µg∙L-1. Después de 17 h, el compuesto eliminó una cantidad significativa de micotoxinas, estando por debajo de 20 µg∙L-1. Los resultados mostraron que este compuesto tiene una buena capacidad de adsorción, puede ser eficaz en la eliminación de micotoxinas en medios acuosos y una excelente actividad antibacteriana y antifúngica. Um nanocompósito a base de bentonita organofílica (BO) e acetato de geranila (AG) foi preparado em shaker por 1 hora, 180 rpm e temperatura ambiente, sendo posteriormente seco em estufa a 90 ºC±2 ºC por 48 horas. Este material foi então caracterizado por sua atividade antibacteriana contra Staphylococcus aureus e Escherichia coli e atividade antifúngica contra Aspergillus flavus e Aspergillus niger, respectivamente. Além disso, a capacidade de adsorção de BO e BO/AG foi avaliada utilizando Aflatoxina B1 na concentração de 107 µg∙L-1. Após 17 h, o compósito removeu uma quantidade significativa de micotoxina, ficando abaixo de 20 µg∙L-1. Os resultados mostraram que este compósito possui boa capacidade de adsorção, pode ser eficaz na remoção de micotoxinas em meio aquoso e excelente atividade antibacteriana e antifúngica.

The development of new antimicrobial polymeric materials is in prominence due to its versatility of applications, especially for the manufacture of active packaging food. Cellulose acetate is an example of polymeric material used to this purpose, due to its characteristics of biodegradability and easy processing, in addition its natural origin and no toxicity. Geranyl acetate is an ester derived from geraniol, which has good antimicrobial properties and good thermal stability, which makes it interesting to be applied as an antimicrobial agent, avoiding the trivial and often problematic metallic nanoparticles and also volatile essential oils. In this work, antibacterial and antifungal cellulose acetate films were obtained through the incorporation of geranyl acetate ester (in concentrations of 0.5 and 1.0% v/v), by using the casting technique. This new material was tested against gram-positive and gram-negative bacteria and fungi. Results showed that it is possible to obtain antibacterial and antifungal cellulose acetate films with the incorporation of geranyl acetate ester, with excellent antibacterial activity against gram-positive and gram-negative bacteria and good antifungal activity. El desarrollo de nuevos materiales poliméricos antimicrobianos se destaca por la versatilidad de aplicaciones, especialmente para la fabricación de envases activos para alimentos. El acetato de celulosa es un ejemplo de material polimérico utilizado para este fin por sus características biodegradables y de fácil procesamiento, además de ser de origen natural y no tener toxicidad. El acetato de geranilo es un éster derivado del geraniol, que tiene una excelente actividad antimicrobiana y una buena estabilidad térmica, lo que lo hace interesante para su aplicación como agente antimicrobiano, evitando nanopartículas metálicas triviales y a menudo problemáticas y también aceites esenciales volátiles. En este trabajo se obtuvieron películas antibacterianas y antifúngicas de acetato de celulosa mediante la incorporación de éster de acetato de geranilo (a una concentración de 0,5% y 1,0% v/v), utilizando la técnica de casting. Este nuevo material ha sido probado contra bacterias gram positivas y gram negativas, así como contra hongos. Los resultados mostraron que es posible obtener películas antibacterianas y antifúngicas de acetato de celulosa con la incorporación de éster de acetato de geranilo, con excelente actividad antibacteriana frente a bacterias gram positivas y gram negativas y buena actividad antifúngica. O desenvolvimento de novos materiais poliméricos antimicrobianos está em destaque devido a versatilidade de aplicações, especialmente para a fabricação de embalagens ativas para alimentos. Acetato de celulose é um exemplo de material polimérico utilizado para este propósito em virtude de sua característica biodegradável e de fácil processamento, além de ser de origem natural e não apresentar toxicidade. Acetato de geranila é um éster derivado do geraniol, que possui excelente atividade antimicrobiana e boa estabilidade térmica, o que o torna interessante para ser aplicado como agente antimicrobiano, evitando as triviais e muitas vezes problemáticas nanopartículas metálicas e também os óleos essenciais voláteis. Neste trabalho, filmes antibacterianos e antifúngicos de acetato de celulose foram obtidos através da incorporação do éster acetato de geranila (na concentração de 0,5% e 1,0% v/v), utilizando a técnica de casting. Este novo material foi testado contra bactérias gram-positivas e gram-negativas e também fungos. Os resultados mostraram que é possível obter filmes antibacterianos e antifúngicos de acetato de celulose com a incorporação do éster acetato de geranila, com excelente atividade antibacteriana contra bactérias gram-positivas e gram-negativas e boa atividade antifúngica.

The continuing evolution of insurance and banking regulation has raised interest in the calibration of different risk measures associated with suitable confidence levels. In particular, Li and Wang (2019) have introduced a probability equivalent level (called PELVE) for the replacement of Value at Risk (VaR) with Conditional Value at Risk (CVaR). Extending their work, we propose two generalizations of PELVE that combine useful theoretical properties with empirical benefits in risk analysis. The former, termed d-PELVE, establishes a correspondence between VaR and suitably parameterized distortion risk measures. The latter, termed g-PELVE, iterates the construction of CVaR starting from VaR to a general coherent risk measure. We state conditions for the existence and uniqueness of the proposed measures and derive additional properties for specific classes of underlying risk functionals. A study of Generalized Pareto Distributions reveals an interesting correspondence between PELVE and g-PELVE, and explores their relationship with the tail index. An empirical application illustrates the usefulness of (g-)PELVE in characterizing tail behavior not only for individual asset returns, but also for possible portfolio combinations.

In this paper, a method for evaluating systemic risk in different geographic areas is presented. The proposed methodology is based on the decomposition by subpopulations of the Gini index, largely used to assess the inequality of income and wealth. This decomposition procedure follows a two-step approach that goes beyond the “classical” decomposition Within and Between components, also allowing the assessment of the contribution to the total inequality for each subpopulation.

In this work we explain the size distribution of business firms using a stochastic growth process that reproduces the main stylized facts documented in empirical studies. The steady state solution of this process is a three-parameter Dagum distribution, which possibly combines strong unimodality with a Paretian upper tail. Thanks to its flexibility, the proposed distribution is able to fit the whole range of firm size data, in contrast with traditional models that typically focus on large businesses only. An empirical application to Italian firms illustrates the practical merits of the Dagum distribution. Our findings go beyond goodness-of-fit per se, and shed light on possible connections between stochastic elements that influence firm growth and the meaning of parameters that appear in the steady state distribution of firm size. These results are ultimately relevant for studies into industrial organization and for policy interventions aimed at promoting sustainable growth and monitoring industrial concentration phenomena.

This work describes the synthesis, characterization and antibacterial activities of a palladium(II) complex with ibuprofen (ibu). Elemental and mass spectrometric data (ESI-QTOF-MS) suggest a 1:2 metal/ligand composition with the minimal formula PdC26H34O4. Infrared (IR) and nuclear magnetic resonance (NMR) spectroscopic measurements indicate ligand coordination to palladium(II) by the carboxylate group in a bidentate mode. Thermal analysis shows that decomposition of the Pd-ibu complex starts at 130 °C and occurs in three exothermic stages. The steps are consistent with the loss of two ibuprofen molecules, with the formation of the final residue of the thermal treatment at 850 °C. DFT calculations (LANL2DZ basis set), supported by the spectroscopic data, led to an optimized dimeric structure for the complex, where two palladium(II) centers are interconnected by four carboxylates in a cage-like structure. The palladium(II) complex with ibuprofen (Pd-ibu) is soluble in dimethylsulfoxide (DMSO) and hexane and is slightly soluble in ethanol and acetonitrile. The complex exhibited antibacterial activities against Gram-positive (Staphylococcus aureus and Enterococcus faecalis) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacterial strains, which is noteworthy in the search of new antibacterial agents. Strong interactions were evidenced with biomolecules such as deoxyribonucleic acid (DNA) and bovine serum albumin (BSA) using agarose gel electrophoresis and fluorescence assays, respectively, which suggests that such molecules are possible targets for the complex in biological medium.

The goal of this paper was to synthesize and characterize core–shell iron-carbon nanoparticles. For this purpose, nanoparticles were synthetized via a hydrothermal co-precipitation route, applying a 22 factorial experimental design with a central point, and varying both the concentration of the iron precursor (iron nitrate) and the reaction temperature. The nanoparticles were characterized via the following analysis: vibrating sample magnometry (VSM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray spectroscopy (EDX), high resolution field emission gun scanning electron microscopy (SEM/FEG) and transmission electron microscopy (TEM) analysis. The results showed that the hydrothermal co-precipitation synthesis route enabled the production of Fe3O4–Fe2O3@C core–shell nanoparticles with dimensions between 4 and 8 nm. An increase in iron nitrate concentration and temperature during synthesis entailed a decrease in the remnant field and the magnetization of the nanoparticles.

Photocatalyst modification with cationic ions has been proven as a versatile technology to enhance the photocatalytic activity. This improvement can be attributed to factors, such as (i) the introduction of new defect states into the band gap, which can reduce the electron–hole recombination and shift the absorption from UV to visible-light wavelengths, (ii) the plasmonic effect of noble metals, and (iii) the visible-light response due to the f–f transitions of rare earths. Different methods are currently used to include cationic ions on the photocatalysts’ surface, such as solvothermal, microemulsion, hydrothermal, microwave, chemical precipitation, photoreduction, and sol–gel. Besides, depending on the ionic radius of the dopant, the concentration, and the doping method, these dopants can be incorporated in substitutional or interstitial positions into photocatalyst lattice or can be found as highly dispersed metal oxide clusters.

Background Synthetic chemical preservatives in food can be harmful to human health. These problems have increasingly attracted concern and interest from researchers, which has led to the study and application of non-toxic essential oils with preservative ability in food products and food packaging. A great challenge in this sense is their facile degradation during processing of the food and manufacturing processes during food packing. Scope and approach Encapsulation is an interesting technique to improve the physical-chemical and microbiological stability of these essential oils, as well as to achieve controlled release. This review provides a detailed overview of encapsulation in the food industry, focusing on the application of procedures to encapsulate antimicrobial essential oils. Key findings and conclusions This review focuses on recent studies related to nanotechnology and the nano and microencapsulation of essential oils. This study provides valuable insight that may be useful for identifying trends in the commercialization of nanotechnological products or for identifying new research areas. The results published to date confirm that the encapsulation promotes the protection of active compounds, enabling industrial applications of active packaging.

The food contamination for pathogenic microorganisms is a serious problem for the food security. Many actions can be taken in order to reduce this pathogenic multiplication, highlighting the use of active packaging for the food conservation, which have antimicrobial agents dispersed in its surface. The metal oxides and its nanoparticles have been shown effective additives for this purpose. With the growing concern with the environmental and the use of less aggressive materials, biodegradable polymers emerge like a good alternative. This work has the goal to investigate the effect on antimicrobial activity against Gram negative (Escherichia coli) and Gram positive (Staphylococcus aureus) bacteria when added zinc oxide nanoparticles (ZnO NPs) in concentration of 1% (wt/wt) in the biodegrable polymer Ecoflex®. The system was homogenized and proccessed in industrial extruder single screw and the polymer’s antimicrobial activity was evaluated by the agar diffusion tests and counting surviving microorganisms with the time. The results showed that the biodegradable polymer Ecoflex®with ZnO NPs exhibit good antibacterial activity.

With the increasing demand of biomaterials, numerous studies have been developed seeking to improve its properties through new obtaining and manufacturing processes. This work aimed to aggregate antimicrobial property to a biocomposite constituted of a matrix of ultra-high molecular weight polyethylene (UHMWPEE) and hydroxyapatite, by the incorporation of zinc oxide nanoparticles. The samples were prepared based on a standard composition containing 95.0 wt% of UHMWPEE and 5.0 wt% of hydroxyapatite (blank). Three compositions were evaluated ranging the amount of zinc oxide nanoparticles incorporated in the standard sample. It was observed that the increase of zinc oxide concentration aggregate a good antibacterial property in the samples tested without cause significant changes in the mechanical properties of the composites.

The oligodynamic property is a lethal effect which some atoms exert over bacteria, fungi and other microorganisms. The oligodynamic property can be promoted by glass microparticles doped by zinc ionic specimens utilizing the ionic exchange processes. This study is aimed at modelling the behavior of adsorption mechanisms of the zinc ions on glass microparticles absorbent, with potential use as antimicrobial material. Aqueous solutions of zinc nitrate were used as the ionic supplying of zinc ions. The amount of zinc adsorbed on the glass was determined by spectroscopy of atomic absorption and with a mass balance analysis for each adsorption conditions. The experimental data were modeled by three Eq.s employed in adsorption kinetics studies: pseudo first order, pseudo second order and Elovich Eq.. The pseudo second order data model presented the better adjust condition. A sample of zinc glass microparticles, prepared at the finest conditions established by the kinetic model of pseudo second order, was submitted to microbiological analysis: agar diffusion test with Pseudomonas aeruginosa and Staphylococcus aureus and with Candida albicans. The glass doped with ionic zinc inhibited the growth of microorganisms in every conducted analysis.

This study evaluated the effects of temperature and speed screw rotation of rigid recycled PVC pipe extrusion process on mechanical properties and dimensional variation. In developing the experiments were used the factorial design method type 2k. Were studied the influence of process variables on the properties of impact resistance, dimensional change and tensile strength of PVC pipe. From this study, it was possible to define the best extrusion process conditions with a point of view on the best properties of PVC pipes. The results indicated that the screw rotation has a significant influence on the impact property. For the dimensional variation, the extrusion temperature had a significant influence. There is no significant statistical values for the tensile strength in the studied variables.

In this work a special electrode configuration with potential application in enzymatic biosensors for the detection of glyphosate was studied. The enzyme used was Horseradish Peroxidase (HRP), which was immobilized on a polyaniline film (PAni), electrodeposited on the surface of the n-type monocrystalline silicon electrode. PAni has the ability to bind to biomolecules and thereby potentiate their biocatalytic properties by favoring the transfer of electrons between enzyme and substrate. Monocrystalline silicon is one of the most used materials in electronic technology due to its semiconductor character. In this work, different parameters were investigated in the electrode preparation, including concentration of polyaniline in the electrodeposition solutions, as well as the electrodeposition times and potentials. The response of the electrode as biosensor was evaluated by the electric current density characteristic of hydroquinone oxidation in the presence of standardized glyphosate solutions. The peroxidase enzyme catalyzes the oxidation of hydroquinone to the o-quinone form in the presence of hydrogen peroxide. In turn, glyphosate inhibits the activity of HRP and causes a reduction of the electric current density in the biosensor electrode. The results obtained with glyphosate using the proposed method are in agreement with the literature and show that the n-Si/PAni/HRP biosensor maintains the catalytic activity and is of considerable interest due to the simple procedure in practical applications and a promising platform for the lack of environmental monitoring for these contaminants.

The industry of polymeric films has been seeking for practical and economical solutions to obtain high quality polymeric films, which comprises the evaluation of a multitude of parameters, such as mechanical and thermal properties and surface characteristics, among which the friction coefficient (FCO) is of great importance. In this work, LLDPE polymeric films were prepared with the addition of erucamide and commercial organophilic montmorillonite nanoclay Cloisite 20A nanocomposites in the concentrations of 5, 10 and 15%. The films were shaped in a single screw balloon tube extruder, then characterized via Transmission Electron Microscopy (TEM), Differential Scanning Calorimetry (DSC), Friction Coefficient (FCO), brightness, opacity and Atomic Force Microscopy (AFM). The results indicated a decrease in and stabilization of the friction coefficient, and allowed an evaluation of the effect of the nanocomposite on the surface of the polymeric films, which involved an increase in brightness and decrease in opacity and roughness.

Lanthanum doped titanium dioxide decorated with silver plasmonic nanoparticles (Ag-La/TiO2 NPs) materials were prepared using a simple ultrasound-assisted wet impregnation method followed by silver photodeposition. The obtained photocatalysts with different Ag contents were characterized by XRD, FE-SEM, EDX, TEM, BET, XPS, DRS and PL techniques. Moreover, the size distribution of the nanoparticles aggregates was assessed. The characterization analysis revealed that La doping slightly changed the crystalline phase of TiO2, increased the amount of surface hydroxyl groups and interacted with TiO2 nanoparticles via Ti–O–La bond, while Ag photodeposition enhanced the absorption of visible light due to the effects of localized surface plamon resonance and significantly decreased electronic recombination rate by the Schottky junction. Furthermore, the combination of Ag-La induced the formation of oxygen vacancies, which increased the amount of adsorbed surface hydroxyl groups in Ag-La/TiO2. In addition, Ag-La possibly decreased the semiconductor surface energy, which acted positively in the reduction of NPs aggregation. These features along with better textural properties (greater surface areas) played a fundamental role in the enhancement of the photocatalytic activity of Ag-La/TiO2 composites for the decolorization of methylene blue under UV-visible irradiation compared to the mono-metallic (La/TiO2 and Ag/TiO2) modified photocatalysts. Finally, a mechanism for the transfer of charge carriers in Ag-La/TiO2 photocatalyst under UV-visible irradiation was proposed.

This paper proposes the surface functionalization with carboxymethyl-β-cyclodextrin (CMCD) of lanthanum-doped TiO2 nanoparticles, to increase their photocatalytic activity for the degradation of organic molecules. CMCD has the capability to capture these compounds, so increasing their density on the catalyst surface and bringing them into close proximity to the hydroxyl radicals formed. Moreover, the doping with lanthanum can generate superficial defects that capture the formed electrons, so avoiding recombination, and can increase the density of –OH groups or water molecules attached to the surface of the catalyst, potentiating the formation of hydroxyl radicals. From the FT-IR, XPS, DTA and TGA characterizations, it is possible to verify the inclusion of the elements on the TiO2 surface and to propose a mechanism responsible for this lanthanum and CMCD inclusion. The kinetics evaluations show an increase in the degradation rate constants after the inclusion of the organic and inorganic molecules, with 99% degradation of a contaminant after 25 minutes.