Magnetic graphene derivates for efficient herbicide removal from aqueous solution through adsorption.

2,4-Dichlorophenoxyacetic acid (2,4-D) is an herbicide and is among the most widely distributed pollutant in the environment and wastewater. Herein is presented a complete comparison of adsorption performance between two different magnetic carbon nanomaterials: graphene oxide (GO) and its reduced form (rGO). Magnetic functionalization was performed employing a coprecipitation method, using only one source of Fe2+, requiring low energy, and potentially allowing the control of the amount of incorporated magnetite. For the first time in literature, a green reduction approach for GO with and without Fe3O4, maintaining the magnetic behavior after the reaction, and an adsorption performance comparison between both carbon nanomaterials are demonstrated. The nanoadsorbents were characterized by FTIR, XRD, Raman, VSM, XPS, and SEM analyses, which demonstrates the successful synthesis of graphene derivate, with different amounts of incorporate magnetite, resulting in distinct magnetization values. The reduction was confirmed by XPS and FTIR techniques. The type of adsorbent reveals that the amount of magnetite on nanomaterial surfaces has significant influence on adsorption capacity and removal efficiency. The procedure demonstrated that the best performance, for magnetic nanocomposites, was obtained by GO∙Fe3O4 1:1 and rGO∙Fe3O4 1:1, presenting values of removal percentage of 70.49 and 91.19%, respectively. The highest adsorption capacity was reached at pH 2.0 for GO∙Fe3O4 1:1 (69.98 mg g-1) and rGO∙Fe3O4 1:1 (89.27 mg g-1), through different interactions: π-π, cation-π, and hydrogen bonds. The adsorption phenomenon exhibited a high dependence on pH, initial concentration of adsorbate, and coexisting ions. Sips and PSO models demonstrate the best adjustment for experimental data, suggesting a heterogeneous surface and different energy sites, respectively. The thermodynamic parameters showed that the process was spontaneous and exothermic. Finally, the nanoadsorbents demonstrated a high efficiency in 2,4-D adsorption even after five adsorption/desorption cycles.

Thick layer drying and storage of rice grain cultivars in silo-dryer-aerator: Quality evaluation at low drying temperature.

Drying rice in a single layer in a silo-dryer-aerator allows uniform drying. The objective of this study was to evaluate the physical, physicochemical, and morphological quality of rice grain cultivars (IRGA 424, BRS Pampeira, and Guri INTA) in the lower (initial time) and upper (final time) layers in a silo-dryer-aerator, employing single-layer loading at low temperatures, using the methods of near-infrared spectroscopy, X-ray diffraction analysis, scanning electron microscopy, and multivariate statistical analysis. Drying rice in silo-dryer-aerator attenuated the moisture diffusivity in the grains, minimizing its effects on the physical, physicochemical, and morphological properties of the grains. However, the physicochemical constituents and morphology of starch were preserved by the low drying temperatures, mainly in the lower layers throughout the 2-month drying. The rice grains of the Guri INTA and BRS Pampeira cultivars were the most resistant to drying and showed greater uniformity on the final quality.

Highly Efficient Adsorption of Tetracycline Using Chitosan-Based Magnetic Adsorbent.

Herein, tetracycline adsorption employing magnetic chitosan (CS·Fe3O4) as the adsorbent is reported. The magnetic adsorbent was synthesized by the co-precipitation method and characterized through FTIR, XRD, SEM, and VSM analyses. The experimental data showed that the highest maximum adsorption capacity was reached at pH 7.0 (211.21 mg g-1). The efficiency of the magnetic adsorbent in tetracycline removal was dependent on the pH, initial concentration of adsorbate, and the adsorbent dosage. Additionally, the ionic strength showed a significant effect on the process. The equilibrium and kinetics studies demonstrate that Sips and Elovich models showed the best adjustment for experimental data, suggesting that the adsorption occurs in a heterogeneous surface and predominantly by chemical mechanisms. The experimental results suggest that tetracycline adsorption is mainly governed by the hydrogen bonds and cation-π interactions due to its pH dependence as well as the enhancement in the removal efficiency with the magnetite incorporation on the chitosan surface, respectively. Thermodynamic parameters indicate a spontaneous and exothermic process. Finally, magnetic chitosan proves to be efficient in TC removal even after several adsorption/desorption cycles.

Low Food Consumption Interferes with the Nutritional Status of Surgical Patients with Neoplasia of the Gastrointestinal Tract.

Nutritional support strongly influence the nutritional status of the surgical neoplastic patients. This study aimed to evaluate the influence of food consumption on the perioperative nutritional status of hospitalized patients with neoplasia of the upper (UGIT) and lower (LGIT) gastrointestinal tract. METHOD: Observational, longitudinal, and prospective study. Data collected: food consumption, Subjective Global Assessment, anthropometry, laboratory tests. RESULTS: Eighty patients were followed up: 43 (54%) in the UGIT and 37 (46%) in the LGIT. The consumption in the perioperative period was lower than the usual consumption in the UGIT and LGIT groups, respectively, of energy (14.2 ± 6.5; 22.8 ± 11.2 Kcal/kg/d, p < 0.001; 13.6 ± 1.2; 19.0 ± 2.0 Kcal/kg/d; p = 0.014), protein (1.1 ± 0.7; 0.6 ± 0.3 g/kg/d, p < 0.001; 0.8 ± 0.1; 0.5 ± 0.1 g/kg/d; p = 0.058), selenium, zinc and copper. Most patients presented in the UGIT and LGIT groups, respectively, worsening malnutrition and muscle depletion according to the Subjective Global Assessment (61.9%; 51.4%) and hypoalbuminemia, mainly in the UGIT in the postoperative. CONCLUSION: Low food consumption during the perioperative period associated with prolongation of the postoperative fasting period worsens the nutritional status of patients undergoing surgery of the gastrointestinal tract for neoplasia, especially in the UGIT group.

Development of an HPLC-UV Method to Assay Empagliflozin Tablets and Identification of the Major Photoproduct by Quadrupole Time-of-Flight Mass Spectrometry.

Diabetes is a set of metabolic disorders that affect >400 million individuals worldwide. Empagliflozin belongs to the gliflozin class and is used orally to treat type 2 diabetes. In this study, a simple stability-indicating HPLC-UV method was developed to assay empagliflozin tablets and its main photoproduct was identified by high-resolution mass spectrometry. The mobile phase, which was optimized by Central Composite Design, was composed of methanol, acetonitrile and purified water (60:5:35 v/v), at a flow rate of 1 mL min-1. The calibration curve was linear in the range of 5-150 µg mL-1. All the validation parameters were met and the method was specific, even in the presence of degradation products. In the forced degradation study, empagliflozin standard and empagliflozin tablets were submitted to several conditions (acidic, alkaline, neutral and oxidant media, thermal, photolytic and humidity), and empagliflozin showed instability under all these conditions. A degradation product generated after drug exposure to ultraviolet C radiation was isolated and analyzed by quadrupole time-of-flight mass spectrometry, and the results suggested that empagliflozin undergoes decomposition by a dechlorination pathway. In silico toxicity was predicted for the degradation product, which showed a high risk of genotoxicity and hepatotoxicity.

Rapid, Noninvasive, and Nondestructive Method for Biofilm Imaging on Metallic Surfaces Using Active Thermography.

A simple, rapid, low-cost method was proposed for the imaging of Pseudomonas aeruginosa biofilms on metallic surfaces using an infrared camera. Stainless steel coupons were cooled to generate a thermal gradient in relation to biofilm for active thermography (AT). Both cooling and image acquisition times were optimized and the images obtained with AT were compared with those from scanning electron microscopy. A free software (Thermofilm) was developed for image processing and the results were compared with the software ImageJ, with good agreement (from 87.7 to 103.8%). Images of coupons treated with sanitizer (peracetic acid) were obtained to show the applicability of the proposed method for biofilm studies. All analytical steps could be performed in 3 min in a noncontact, nondestructive, low-cost, portable, and easy-to-use way.

Use of prebiotic sources to increase probiotic viability in pectin microparticles obtained by emulsification/internal gelation followed by freeze-drying.

The aim of this study was to investigate the influence of hi-maize, inulin, and rice bran in the survival of Lactobacillus acidophilus LA-5 in pectin microparticles obtained by internal gelation and subjected to freeze-drying. For this, the development of a matrix capable of extending Lactobacillus acidophilus viability to develop new functional foods was emphasized. Microparticle size, encapsulation efficiency, probiotic survivability after gastrointestinal simulation, and storage stability were analyzed. The pectin + inulin encapsulation matrix presented the highest encapsulation efficiency (68.1%) compared to the other treatments. Microparticle sizes ranged from 166 ± 2 µm (pectin + hi-maize) to 345 ± 9 µm (pectin + inulin). The microparticles added from the different prebiotics showed better microorganism protection when compared to treatment without prebiotics, which presented greater viability in the gastrointestinal simulation. Under storage conditions of 25 °C and -18 °C, the microparticles containing hi-maize, inulin, and rice bran maintained the probiotic microorganisms viable for longer periods than the pectin microparticles. At 7 °C, the pectin + rice bran treatment stood out from the other treatments, as it was able to maintain probiotic stability during 120 days of storage.

The effect of enzymatic crosslinking on the viability of probiotic bacteria (Lactobacillus acidophilus) encapsulated by complex coacervation.

Lactobacillus acidophilus were encapsulated by complex coacervation followed by transglutaminase crosslinking, aiming to improve the resistance of the microcapsules and improve the protection for probiotics. Subsequently, microcapsules were dried by freeze drying. The encapsulation efficiency, morphology, thermal resistance, gastrointestinal simulation and storage stability were analysed for wet and dry forms. The treatments offered high encapsulation efficiency (68.20-97.72%). Transglutaminase maintained the structure rounded, multinucleate and homogeneous distribution of probiotics in the microcapsules. In relation to the thermal resistance, in general, microencapsulation was effective in protecting and crosslinked microcapsules demonstrated greater protection for probiotics, obtaining viable cell counts of up to 10 log CFU g-1, approximately. On exposure to the simulated gastrointestinal tract, microencapsulation coupled to crosslinking demonstrated good results and the dry form was more efficient in the protection and the treatment with greater amount of transglutaminase was highlighted (9.07 log CFU g-1). As for storage, probiotic viability was maintained for up to 60 days in freezing temperature, with counts of up to 9.59 log CFU g-1. The results obtained in the present work are innovative and present a promising alternative for the protection of probiotics and their addition in food products.

Bioimaging Metallomics.

This chapter focuses on bioimaging in metallomics, which involves metal and metalloids distribution in animal tissues. It starts with laser ablation-inductively coupled plasma-mass spectrometry followed by secondary ion mass spectrometry, synchrotron-based X-ray fluorescence, and electron microscopy, including transmission electron microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The basic principles of these techniques and their application for qualitative and quantitative imaging of elements are presented. Sample preparation for bioimaging is briefly discussed. The usefulness of element bioimaging is demonstrated for cells and several animal tissues, including the brain, liver, hair, eye, teeth, and bone. As such, this chapter addresses the state of the art in bioimaging metallomics.

Encapsulation of Lactobacillus acidophilus La-5 and Bifidobacterium Bb-12 by spray drying and evaluation of its resistance in simulated gastrointestinal conditions, thermal treatments and storage conditions / Encapsulação de Lactobacillus acidophilus La-5 e Bifidobacterium Bb-12 por spray dryer e avaliação da sua resistência em condições gastrointestinais simuladas, tratamentos térmicos e em condições de armazenamento

ABSTRACT: Lactobacillus acidophillus La-5 (ML) and Bifidobacterium Bb-12 (MB) microparticles were produced at different temperatures by spray dryer. The influence of different temperatures on the viability, encapsulation efficiency, water activity and moisture were evaluated. Microparticles that presented more viability were submitted to thermal resistance, gastrointestinal simulation, storage stability, morphology and particle size analyses. Drying temperature of 130°C showed higher encapsulation efficiency, 84.61 and 79.73% for Lactobacillus acidophillus (ML) and Bifidobacterium Bb-12 (MB) microparticles, respectively. In the evaluation of thermal resistance and gastrointestinal simulation, the microparticles of Lactobacillus acidophillus La-5 (ML) presented higher survival than Bifidobacterium Bb-12 (MB) under these conditions. In storage viability only the Lactobacillus acidophillus La-5 (ML) microparticles remained viable at all evaluated temperatures during the 120 days. The particle sizes reported were 4.85 for Lactobacillus acidophillus La-5 (ML) and 8.75 for Bifidobacterium Bb-12 (MB), being in agreement with the desired values for products obtained by spray dryer. Finally, the Lactobacillus acidophilus La-5 (ML) microparticles were shown to be more resistant under the conditions evaluated in this study.

RESUMO: Micropartículas de Lactobacillus acidophillus La-5 (ML) e Bifidobacterium Bb-12 (MB) foram produzidas em diferentes temperaturas de secagem no spray dryer. A influência das diferentes temperaturas sobre a viabilidade, eficiência de encapsulação, atividade de água e umidade foram avaliadas. As micropartículas que apresentaram maior viabilidade foram submetidas a análises de resistência térmica, simulação gastrointestinal, estabilidade ao armazenamento, morfologia e tamanho de partícula. A temperatura de secagem de 130°C mostrou maior eficiência de encapsulação, 84.61 e 79.73% para micropartículas de Lactobacillus acidophillus (ML) e Bifidobacterium Bb-12 (MB), respectivamente. Na avaliação da resistência térmica e simulação gastrointestinal as micropartículas de Lactobacillus acidophillus La-5 (ML) apresentaram maior sobrevivência que Bifidobacterium Bb-12 (MB) nestas condições. Na viabilidade ao armazenamento somente as micropartículas Lactobacillus acidophillus La-5 (ML) mantiveram-se viáveis em todas as temperaturas avaliadas durante os 120 dias. Os tamanhos de partícula encontrados foram de 4.85 para Lactobacillus acidophillus La-5 (ML) e 8.75 para Bifidobacterium Bb-12 (MB), estando de acordo aos valores desejáveis para produtos obtidos por spray dryer. Por fim, as micropartículas de Lactobacillus acidophilus La-5 (ML) demostraram ser mais resistentes frente as condições avaliadas neste estudo.

Simultaneous diffuse reflectance infrared determination of clavulanic acid and amoxicillin using multivariate calibration techniques.

A method for simultaneous determination of clavulanic acid (CA) and amoxicillin (AMO) in commercial tablets was developed using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and multivariate calibration. Twenty-five samples (10 commercial and 15 synthetic) were used as a calibration set and 15 samples (10 commercial and 5 synthetic) were used for a prediction set. Calibration models were developed using partial least squares (PLS), interval PLS (iPLS), and synergy interval PLS (siPLS) algorithms. The best algorithm for CA determination was siPLS model with spectra divided in 30 intervals and combinations of 2 intervals. This model showed a root mean square error of prediction (RMSEP) of 5.1 mg g(-1). For AMO determination, the best siPLS model was obtained with spectra divided in 10 intervals and combinations of 4 intervals. This model showed a RMSEP of 22.3 mg g(-1). The proposed method was considered as a suitable for the simultaneous determination of CA and AMO in commercial pharmaceuticals products.

Total sulfur determination in residues of crude oil distillation using FT-IR/ATR and variable selection methods.

Total sulfur concentration was determined in atmospheric residue (AR) and vacuum residue (VR) samples obtained from petroleum distillation process by Fourier transform infrared spectroscopy with attenuated total reflectance (FT-IR/ATR) in association with chemometric methods. Calibration and prediction set consisted of 40 and 20 samples, respectively. Calibration models were developed using two variable selection models: interval partial least squares (iPLS) and synergy interval partial least squares (siPLS). Different treatments and pre-processing steps were also evaluated for the development of models. The pre-treatment based on multiplicative scatter correction (MSC) and the mean centered data were selected for models construction. The use of siPLS as variable selection method provided a model with root mean square error of prediction (RMSEP) values significantly better than those obtained by PLS model using all variables. The best model was obtained using siPLS algorithm with spectra divided in 20 intervals and combinations of 3 intervals (911-824, 823-736 and 737-650 cm(-1)). This model produced a RMSECV of 400 mg kg(-1) S and RMSEP of 420 mg kg(-1) S, showing a correlation coefficient of 0.990.

Evaluation of oxygen pressurized microwave-assisted digestion of botanical materials using diluted nitric acid.

The feasibility of diluted nitric acid solutions for microwave-assisted decomposition of botanical samples in closed vessels was evaluated. Oxygen pressurized atmosphere was used to improve the digestion efficiency and Al, Ca, K, Fe, Mg and Na were determined in digests by inductively coupled plasma optical emission spectrometry (ICP OES). Efficiency of digestion was evaluated taking into account the residual carbon content (RCC) and residual acidity in digests. Samples were digested using nitric acid solutions (2, 3, 7, and 14 mol L(-1) HNO(3)) and the effect of gas phase composition inside the reaction vessels by purging the vessel with Ar (inert atmosphere, 1 bar), air (20% of oxygen, 1 bar) and pure O(2) (100% of oxygen, 1 bar) was evaluated. The influence of oxygen pressure was studied using pressures of 5, 10, 15 and 20 bar. It was demonstrated that a diluted nitric acid solution as low as 3 mol L(-1) was suitable for an efficient digestion of sample masses up to 500 mg of botanical samples using 5 bar of oxygen pressure. The residual acidities in final digests were lower than 45% in relation to the initial amount of acid used for digestion (equivalent to 1.3 mol L(-1) HNO(3)). The accuracy of the proposed procedure was evaluated using certified reference materials of olive leaves, apple leaves, peach leaves and pine needles. Using the optimized conditions for sample digestion, the results obtained were in agreement with certified values. The limit of quantification was improved up to a factor of 14.5 times for the analytes evaluated. In addition, the proposed procedure was in agreement with the recommendations of the green chemistry once it was possible to obtain relatively high digestion efficiency (RCC<5%) using only diluted HNO(3), which is important to minimize the generation of laboratory residues.