ABSTRACT This work aimed at investigating the viability of near infrared spectrometry (NIR), associated with chemometric methods, in order to identify differences at the levels of vigor of naturally and artificially aged soybean seeds. Seeds of six soybean genotypes were analyzed when freshly harvested, after natural aging in storage for eight months, and after artificial aging at the temperature of 41 °C for 96 hours. The seed moisture content, germination potential and vigor were evaluated. Also, there were measured the content of protein, oil and of the fatty acids: palmitic, stearic, oleic, linoleic and linolenic. The NIR spectra were obtained from the freeze-dried and grinded seeds. The natural and artificial aging of the seeds promote deterioration at distinct levels, reflecting in differences in seed vigor. The regions of the electromagnetic spectrum between wavelengths of 1000-1200 nm, 1350-1450 nm, 1800-1900 nm and 2300-2400 nm are important to distinguish the levels of quality of the soybean seeds. The contents of oil and protein have a relationship with the physiological quality of the seeds. Also, the most relevant wavelengths for the classification of seed vigor present a relationship with these compounds. NIR spectroscopy, in combination with chemometric methods, presents potential to be used in the classification of soybean seeds regarding their physiological quality.

This work describes a green synthesis, the characterization, and biological evaluation of silver nanoparticles (AgNPs). The AgNPs suspension was synthesized using aqueous leaf extract of Eucalyptus grandis, which presented a characteristic band at 407 nm in the UV-Vis spectrum. The AgNPs presented a spherical shape and size of 9.7 ± 0.3 nm. The nanoparticles were stable over a month, indicating that E. grandis’ extract is suitable for their preparation and stabilization. The X-ray analysis showed that the crystallinity of AgNPs corresponded to the centered face phase of silver. The antibacterial and leishmanicidal activities of AgNPs were evaluated. The AgNPs presented antibacterial activity on the Gram-negative bacteria Escherichia coli at 53.9 µg mL-1. The leishmanicidal activity evaluation against promastigote forms of Leishmania infantum, Leishmania amazonensis, and Leishmania braziliensis showed that the biological response is dependent on the volume of AgNP suspension. It was demonstrated that L. infantum was more sensitive to the nanoparticle’s treatment than L. amazonensis and L. braziliensis. The treatment of L infantum promastigotes with 150 µL of AgNP suspension reduced parasite growth by 67.9%, a result which was similar to the treatment with 1 (66.7%) or 2 µL (70.6%) of amphotericin B used as a positive control.

Abstract The determination of hydroxymethylfurfural (HMF) in bee honey is performed by the spectrophotometric methods Winkler's and White's. The Winkler method reads the absorbances in the visible region of the spectrum, and the White method measures in the ultraviolet (UV) and visible regions of the spectrum. This study aims to compare the spectrophotometric methodologies of White and Winkler to the determination of HMF in bee honey. For the study, it was used a UV-visible spectrophotometer, 10 mm optical path quartz cuvettes, and ten bee honey samples of different flowering. Absorbances at 550 nm were analyzed by the Winkler method; absorbances at 284 nm and 336 nm in the White method; and a comparison of HMF concentration (mg/kg) was carried out between the methods. The results showed significant differences (p<0.05) in HMF concentration determined by both methods. The main conclusion is that the Winkler method presents higher HMF values than the White method.

The plasmonic properties of Au nanoparticles (AuNP), which allow the observation of enhanced spectroscopic effects, are strongly affected by the aggregation and precipitation caused by the strong interactions between nanoparticles. To avoid AuNP aggregation and precipitation, the present study proposes coating with MnO2, forming AuNP@MnO2 core-shell structures. The MnO2 layers presented 1-10 nm thickness so that highly surface-enhanced fluorescence was obtained with maximum intensity given by 5 nm thick MnO2. The decrease in Raman intensity could be controlled, despite the inherent reduction in surface-enhanced Raman scattering (SERS) intensity with increasing adsorbate-surface distance. The decrease in Raman intensity was compensated by increasing AuNP stability caused by the MnO2 shell.

The use of conducting polymers as coating layers for the protection of surfaces against corrosion represents an important topic for investigation, as reported in the literature. In this work, polypyrrole/Fe3O4 nanoparticles (Fe3O4_NPs/PPy) hybrid nanocomposites (HN) were incorporated as anticorrosive additives in an epoxy paint to protect SAE 1010 carbon steel from corrosion. The HN particles were obtained by chemical polymerization of pyrrole in an aqueous solution in the presence of Fe3O4_NPs and were characterized by infrared absorption spectrophotometry, dynamic light scattering (DLS), X-ray diffraction (XRD), transmission electron microscopy (TEM). The electrochemical impedance spectroscopy (EIS) was used in the analysis of the electrochemical response of the coated surface with and without HN. DLS data showed that the Fe3O4_NPs and Fe3O4_NPs/PPy obtained in solution present average diameters of (19.7 ± 9.6) nm and (63.5 ± 27.7) nm, respectively. TEM images showed Fe3O4_NPs with smaller sizes (10 nm - 30 nm), and that the HN had diameters smaller than 100 nm, consisting of Fe3O4 cores coated with polypyrrole. EIS measurements have shown that the addition of HN to the epoxy paint could improve the efficiency of the anticorrosive coating when compared to the original epoxy paint prepared without any corrosion inhibitor.

ABSTRACT: This study applied spectroradiometry techniques with hyperspectral data to identify the correlations between sugarcane leaf reflectance and the contents of Nitrogen (N), phosphorus (P), Potassium (K), Sulfur (S), Calcium (Ca) and Magnesium (Mg). During the harvests 2019/20 and 2020/21, sugarcane was introduced to nutritional stress by the application of limestone doses. Liming was applied in a fractional way and, at the end of five years, the amounts corresponded to 0, 9, 15 and 21 t ha-1 of dolomitic limestone. The leaf hyperspectral reflectance data and the state of nutrients in the exponential growth phase of the culture were registered. The wavelengths correlated with N, P, K, S, Ca and Mg were identified using the Spearman’s correlation analysis. The test of similarity (ANOSIM) and the Principal Component Analysis (PCA) were applied to evaluate data variability, as well as the Partial Least Squares Regression (PLSR) for the prediction of the nutritional contents. The order of the degree of correlation in the region of visible was: P > K > N > Ca > S > Mg and for the region of the near infrared: P > K > Ca > N > S > Mg. P presented peaks with high correlations in the wavelengths 706-717 nm (-0.78) and 522-543 nm (-0.76). The values of the PLSR registered the best spectral responses in the region of VIS and red-edge, regions that are more sensitive to the deficiency of sulfur, potassium and phosphorus.

RESUMO: Este estudo aplicou técnicas de espectrorradiometria com dados hiperespectrais para identificar as relações da reflectância foliar da cana-de-açúcar com os teores de Nitrogênio (N), Fósforo (P), Potássio (K), Enxofre (S), Cálcio (Ca) e Magnésio (Mg). Durante as safras 2019/20 e 2020/21 a cana foi induzida ao estresse nutricional a partir da aplicação de doses de calcário. A calagem foi aplicada de forma fracionada e ao final de cinco anos as quantidades corresponderam a 0, 9, 15 e 21 t ha-1 de calcário do tipo dolomítico. Foram registrados os dados de reflectância hiperespectral da folha e o estado de nutrientes na fase de exponencial crescimento da cultura. Os comprimentos de onda correlacionados ao N, P, K, S, Ca e Mg foram identificados usando análise de correlação de Spearman. Aplicou-se o teste de similaridade (ANOSIM) e Análise de Componentes Principais (ACP) para avaliar a variabilidade dos dados, assim como, a Regressão por Mínimos Quadrados Parciais (PLRS) para a predição dos teores nutricionais. A ordem do grau de correlação na região do visível foi: P > K > N > Ca > S > Mg e para região do infravermelho próximo: P > K > Ca > N > S > Mg. O P teve picos com alta correlação nos comprimentos de onda 706-717 nm (-0,78) e 522-543 nm (-0,76). Os valores do PLRS registraram melhores respostas espectrais na região do VIS e red-edge, regiões mais sensíveis a deficiência do enxofre, potássio e fósforo.

ABSTRACT Hyperspectral sensors and regression analysis have been used to analyze the most important spectral ranges for biophysical parameters of target crops, aiding in management decision-making. This study aimed to analyze the spectral response of Brachiaria brizantha cv. Marandú leaves to increasing rates of urea fertilization and predict leaf nitrogen content (LNC). Four rates of urea fertilization (0, 25, 50, and 75 kg of N ha-1) were applied. Eight leaves were collected per plot seven times at monthly intervals and subjected to hyperspectral analysis. Leaf spectral responses differed statistically within the visible region, particularly at 550 nm (green). The regression models achieved moderate to good R2 values (0.53 to 0.83) for predicting LNC and identified important wavelengths in the red edge region (715 to 720 nm). These findings demonstrate the potential of spectral analysis to detect changes and forecast leaf nitrogen content in B. brizantha cv. Marandú crops at different fertilization levels.

In this work, composite powders of aluminum alloy 7075 (AA7075) reinforced by 2 weight percent of nanosized particles of silicon carbide (SiC), titanium nitride (TiN), and zinc oxide (ZnO) were produced in a bath of isopropyl alcohol by high energy ball milling during 480 min at 25 ºC, 900 rpm, and Balls-to-Powder Weight Ratio (BPR) of 20:1. The techniques of X-Ray Diffraction (XRD), Laser Diffraction Method (LDM), Scanning Electron Microscopy (SEM), and microanalysis of Energy Dispersive Spectroscopy (EDS) were used to characterize the powders as received and processed. Then, the composites were hot extruded and characterized by XRD, SEM, and microhardness Vickers (HV). The milling process reduces the crystallite and particle size to around 30 nm and 10 µm, respectively. After extrusion, a fine microstructure and good consolidation were found for all bars, except for AA7075 as received. The ranging microhardness values were from 97 HV to 121 HV.

Abstract Polymersomes are nanometric vesicles that can encapsulate large and hydrophilic biomolecules, such as proteins, in the aqueous core. Data in literature show large variation in encapsulation efficiency (%EE) values depending on the method used for calculation. We investigated different approaches (direct and indirect) to quantify the %EE of different proteins (catalase, bovine serum albumin-BSA, L-asparaginase and lysozyme) in Pluronic L-121 polymersomes. Direct methods allow quantification of the actual payload of the polymersomes and indirect methods are based on the quantification of the remaining non-encapsulated protein. The protein-loaded polymersomes produced presented approximately 152 nm of diameter (PDI ~ 0.4). Higher %EE values were obtained with the indirect method (up to 25%), attributed to partial entanglement of free protein in the polymersomes poly(Ethylene Glycol) corona. For the direct methods, vesicles were disrupted with chloroform or proteins precipitated with solvents. Reasonable agreement was found between the two protocols, with values up to 8%, 6%, 17.6% and 0.9% for catalase, BSA, L-asparaginase and lysozyme, respectively. We believe direct determination is the best alternative to quantify the %EE and the combination of both protocols would make results more reliable. Finally, no clear correlation was observed between protein size and encapsulation efficiency.

RESUMO Selecionar novos genótipos de batata-doce, que sejam adaptados às condições edafoclimáticas e de cultivo das regiões produtoras, se faz necessário. Assim, objetivou-se avaliar o desempenho agronômico de genótipos experimentais de batata-doce de polpa branca em lavouras comerciais, buscando obter indicação do seu mérito como cultivares comerciais. Os experimentos foram conduzidos nos munícipios de Presidente Prudente-SP, Emilianópolis-SP, Tarabai-SP e Álvares Machado-SP. Foi adotado o delineamento experimental de blocos ao acaso, com cinco repetições, avaliando-se os genótipos UZBD-L1-04 e UZBD-L5-29, e utilizando as testemunhas Ligeirinha Paulista, Canadense e INIA Arapey. Foram avaliados a produtividade total de raízes tuberosas, número de raízes tuberosas comerciais, produção de raízes tuberosas comerciais, massa média de raízes tuberosas comerciais, porcentagem de massa seca de raízes tuberosas comerciais, sólidos solúveis, resistência a danos causados por pragas, comprimento, diâmetro e aparência das raízes. Concluiu-se que o genótipo UZBD-L1-04 obteve desempenho superior aos demais (média dos ambientes para produtividade total de raízes tuberosas de 31,76 t/ha), e possuindo potencial como cultivar para a região.

ABSTRACT Selecting new sweet potato genotypes that are adapted to the soil, climate, and cultivation conditions of the producing regions is necessary. Thus, the objective of this work was to evaluate the agronomic performance of experimental genotypes of white-fleshed sweet potato in commercial fields, seeking to evaluate their potential as commercial cultivars. The experiments were carried out in the municipalities of Presidente Prudente, Emilianópolis, Tarabai, and Álvares Machado in São Paulo state. The randomized complete block design with five repetitions was used in the experiments, where the genotypes UZBD-L1-04 and UZBD-L5-29 were evaluated along with the controls Ligeirinha Paulista, Canadense, and INIA Arapey. The assessed traits were tuberous root total yield, number of commercial tuberous roots, commercial tuberous root yield, average mass of commercial tuberous roots, percentage of commercial tuberous root dry mass, soluble solids, resistance to pest-caused damage, root length, diameter, and appearance. UZBD-L1-04 performed better than the other genotypes (the average of environments for tuberous root total yield was 31.76 t/ha), showing great potential as a commercial cultivar for the studied region.

Abstract This work examines the prospects of a low-cost retroreflection optical sensor system for detection of the interface between two immiscible liquids, for applications in oil separation tanks. The sensor in its simplest configuration comprises a bare fiber optic tip, cleaved at an angle of 90º relative to the longitudinal fiber axis. The device tested experimentally is based on a 2x2 bidirectional coupler, which connects the sensor tip to a laser and two photodetectors, one used to measure the signal and the other as a reference. From experiments conducted in a laboratory wateroil system, the measured retro-reflected signal was very small, and of the same order as the differential signal due to low optical contrast liquids. To overcome this difficulty, the detection system was designed with an amplification stage, followed by filtering of the digitally converted signal. With this strategy, an accuracy of 99.7% was reached. On the light of the performance measured by the bare fiber tip configuration, an analysis on the potential improvement in performance obtained, by applying a thin layer of gold to the tip of the sensor, was made. Simulated results indicated that, for an optimized gold film, 13 nm thick, a 13fold improvement in the sensor detection limit is obtained.

RESUMO A deficiência de vitamina A é frequente nos países em desenvolvimento. Neste contexto, a batata-doce pode ser uma aliada na reversão desse quadro, uma vez que apresenta baixo custo de aquisição e elevada disponibilidade de mercado. Além disso, alguns genótipos apresentam polpa de coloração laranja, rica em betacaroteno, que é o precursor da vitamina A. Assim, objetivou-se com a presente pesquisa selecionar genótipos de batata-doce de polpa laranja por meio do emprego de dois índices de seleção (Smith e Hazel e Mulamba & Mock). Para tanto, foram avaliadas sete famílias de meio irmãos com raízes de polpa laranja (141 genótipos experimentais e a cultivar comercial Beauregard), verificando-se os parâmetros produtivos, aparência externa das raízes, a intensidade de cor da polpa e suscetibilidade à Euscepes postfasciatus. Dessa forma, os genótipos UZBD-C-14, UZBD-U1-25, UZBD-F-15, UZBD-C-30, UZBD-K-32, UZBD-U1-10, UZBD-L2-14 e UZBD-L5-67 apresentaram-se mais promissores, demonstrando maior equilíbrio para os caracteres avaliados. Ademais, esses genótipos estão aptos a novos estudos, com propósito de confirmar o desempenho produtivo e de qualidade de raízes, além dos parâmetros bioquímicos que comprovem a herança do caráter que regula a biofortificação mediada pelos carotenos.

ABSTRACT Vitamin A deficiency is common in developing countries. Sweet potato can be an ally in reversing this situation since it has a low acquisition cost and high market availability. In addition, some genotypes have orange-flesh roots, rich in beta-carotene, which is the precursor of vitamin A. Thus, the objective of this research was to select orange-fleshed sweet potato genotypes using two selection indices (Smith and Hazel and Mulamba & Mock). For this purpose, seven half-sibling families with orange flesh roots (141 experimental genotypes and the commercial cultivar Beauregard) were evaluated, assessing yield-related traits, external appearance of roots, pulp color intensity, and susceptibility to Euscepes postfasciatus. The genotypes UZBD-C-14, UZBD-U1-25, UZBD-F-15, UZBD-C-30, UZBD-K-32, UZBD-U1-10, UZBD-L2-14, and UZBD-L5-67 were the most promising, showing greater balance for the evaluated characters. Furthermore, these genotypes are suitable for new studies to confirm their productive performance and root quality and evaluate the biochemical parameters that prove the inheritance of the character regulating biofortification mediated by carotenes.

Abstract A novel pigment of β-LiAlSi2O6:Cr ceramic was developed by a partial proteic sol-gel process, using gelatin as a ligand. X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and visible and near-infrared diffuse reflectance spectroscopy (vis-NIR DRS) were performed. XRD results confirmed that the crystal structure of the lattice corresponded to β-LiAlSi2O6 (or β‑spodumene), and the addition Cr3+ ions by doping did not interfere in the formation of this crystalline phase. EDS confirmed the homogeneous existence of Cr3+ dopant in β‑LiAlSi2O6 particles. From the vis‑NIR DRS, selective absorption of visible light wavelengths was identified in the bands of 425 nm and 600 nm, resulting in the perception of a yellowish-green color when β-LiAlSi2O6 is doped with Cr3+. CIE-XYZ colorimetric coordinates were generated to characterize the resulting colors. The obtained results demonstrated the viability of β‑LiAlSi2O6:Cr synthesis by a proteic sol‑gel route and its great potential for obtaining a yellowish-green ceramic pigment.

ABSTRACT Manganese oxides were synthesized during 40 min at 140 ºC via Microwave-Assisted Hydrothermal (MAH) method and treated at different temperatures in order to evaluate the phase evolution using structure refinement (Rietveld method). The samples obtained were heat treated at temperatures defined by means of thermal analysis (160 ºC, 480 ºC, 715 ºC, 870 ºC, 920 ºC and 1150 ºC) and analyzed by X-Ray Diffractometry (XRD), X-Ray Fluorescence (XRF), Fourier Transform Infrared (FTIR) spectroscopy, Raman scattering, UV-Vis absorption and Scanning Electron Microscopy (SEM). Structural characterizations allowed to identify five distinct phases: α-MnO2, Mn3O4, Mn5O8, Na2Mn5O10 and Na4Mn9O18 with weight percentages dependent on the heat treatment. The hausmannite structure (average crystallite size ranging from 28.9 nm to 99.1 nm) is present in all samples and go through various oxidation and reduction processes from 160 ºC to 1150 ºC without any major variation in the lattice parameters. Chemical characterizations identifies the presence of Na+ ions in all samples, either as substitution defects or as components of specific crystalline structures (Na2Mn5O10 and Na4Mn9O18), showing that the synthesized manganese oxides works as Na+ intercalation compounds, important materials for energy storage devices optimization. The results presented enables a better interpretation of the thermal and structural characteristics of manganese oxides synthesized via MAH.

Our work presents a comparative study of morphological characteristics and the osteogenic potential of MC3T3-E1 cells on different modified surfaces of titanium: nanostructured TiO2 with 20 and 100 nm nanotube diameter, and sandblasting and acid etching, commercially known as SLA. Nanostructured TiO2surface was prepared by anodizing of titanium plates, while SLA surface was provided by commercial supplier. Surfaces were characterized by SEM, EDS, AFM, and water contact angle measurements. In order to evaluate cell response,in vitrotests of MTT, alkaline phosphatase and staining with alizarin red were performed. From the results ofin vitro tests, 100 nm nanotubular surface showed lower levels of cell mineralization, differentiation and adhesion. In general, 20 nm TiO2nanotubular and SLA surfaces promoted similar response from osteoblasts. As a result, 20 nm nanotubular surface proved to be a possible alternative to SLA surface with potential for use in oral implantology market.