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In this work, is proposed an analytical method for the determination of nickel in natural water and sediment samples using solid-phase extraction with a mini-column of bamboo fibres modified with 5...

This study aims to develop of a method based on extraction induced by emulsion breaking (EIEB) to determine Mg, Ca, Zn, and Na in cocoa butter by flame atomic absorption and emission spectrometry. The method has been optimized using Box-Behnken design as a response surface methodology for the variables: nitric acid concentration, extraction time, and surfactant concentration. Optimal conditions were the following, for 1.00 g of sample: 1.0 mL of solution extractor containing 0.7% (w v−1) Triton X-114 surfactant in 1.8 mol L−1 nitric acid, and 7 min for extraction, being the emulsion breaking promoved by heating to 96 °C in a water bath followed of centrifugation. Under this conditions, quantitation limits were 0.33, 0.67, 0.05, and 0.33 mg kg−1 for Mg, Ca, Zn, and Na, respectively; precision, obtained by values of RSD%, was less than 9.6%; accuracy, evaluated by addition and recovery test on three different cocoa butter samples and comparison of extraction with a reference method established in the literature, was between 90 and 117%. The proposed method of EIEB has been applied to cocoa butter samples, and the found concentrations (mg kg−1) varied between 15.8 and 37.1 (Mg), 1.20 and 5.18 (Ca), 0.20 and 1.05 (Zn), and 0.60 and 1.93 (Na). Therefore, the EIEB method is simple, efficient, with low cost and reagent consumption, presents good precision and accuracy, and is an excellent alternative for the element determinations in cocoa butter.

This study evaluates the efficiency of acid extraction and total digestion to determine the presence of metals in geopropolis produced by the stingless bee Melipona scutellaris. Geopropolis samples were collected at five meliponaries in the city and in the metropolitan region of Salvador, Bahia State, Brazil. The sample treatment methods comprised acid extraction and total digestion. The Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES) technique was used to quantify Cd, Cu, Cr, Pb, and Zn. Geopropolis samples submitted to both digestion methods showed statistical differences. For both methods, Cr and Zn showed the highest concentrations, while those of Cd were the lowest. The Cr concentration for determination by total digestion was 37.53 mg/kg, while for acid extraction it was 32.90 mg/kg. For Zn, the concentration was 17.65 mg/kg and 8.85 mg/kg for total digestion and acid extraction, respectively. The total digestion method showed the highest concentrations of the metals evaluated; however, acid extraction (USEPA 3050b) is a more straightforward procedure for metal evaluation in geopropolis samples and presented values that support the use of geopropolis as a bioindicator. The acid extraction method USEPA 3050b, in combination with detection using ICP OES, showed efficiency in analyses carried out to determine metals in geopropolis.

The use of statistical tools in the optimization of bioactive extraction processes increases efficiency and reduces process costs, indicating the optimal conditions for obtaining the best results. The objective of this work was to optimize an ultrasound-assisted extraction procedure and to quantify phenolic compounds in Capsicum frutescens samples. In the optimization of the extraction solution, simplex-centroid mixture design for the proportions optimization of the extractor components (water, methanol, and ethanol) was used. A two-level factorial design (23) was used for the preliminary evaluation of the factors that influenced the extraction process; before this step, a Box-Behnken design was carried out to optimize the factors of solvent volume, sonication time, and temperature with the desirability function as a response. The best mixture composition was 95% methanol and 5% water and the best experimental conditions for the process variables were 16 mL, 15 min, and 55 °C. Applying the method to pepper samples, twelve compounds were determined by HPLC–DAD. The relative standard deviations (RSD) found for all analytes were lower than 3.0%. The accuracy was evaluated using addition/recovery test with recoveries between 81 and 95%. The Box-Behnken and mixture designs are efficient tools for optimizing the analytical method using ultrasound to extract phenolic compounds from C. frutescens. The procedure was applied for extraction phenolics compounds in three papers samples and the concentrations found were trans-cinnamic acid (

HIGHLIGHTS The salinity of the water reduces the number and diameter of the fruits and, the total weight of West Indian cherry fruits. Potassium-phosphorus fertilization attenuates the deleterious effects of salt stress on West Indian cherry production. The effect of water salinity on West Indian cherry fruit varies with salt stress intensity and expo-sure time to salinity. RESUMO Os recursos hídricos no Nordeste brasileiro comumente apresentam elevadas concentrações de sais, o que limita a produção das culturas. Assim, o fornecimento de nutrientes, como o K e P de forma combinada pode reduzir a absorção dos íons Na+ e Cl- nas plantas, tornando viável o uso de águas salinas. Nesse contexto, objetivou-se, avaliar a produção de aceroleira cv. BRS 366 Jaburu sob irrigação com águas salinas e adubação com potássio-fósforo em dois ciclos produtivos no segundo ano de cultivo. Os tratamentos foram distribuídos em blocos casualizados, em esquema fatorial 5 x 4 com três repetições, relativos a cinco valores de condutividade elétrica da água de irrigação (0,6; 1,4; 2,2; 3,0 e 3,8 dS m-1), e quatro combinações de potássio/fósforo (100/100, 85/85, 60/60 e 45/45% da recomendação para a cultura). No primeiro ciclo produtivo, as plantas irrigadas com águas de 1,4 e 1,9 dS m-1, obtiveram o maior peso médio e total de frutos, respectivamente, enquanto que no segundo a irrigação com águas a partir de 0,6 dS m-1 reduziu a produção. A adubação com 45/45% da recomendação de K2O/P2O5 resulta em maior número e peso de frutos de acerola no primeiro ciclo produtivo, independentemente do nível salino.

HIGHLIGHTS Electrical conductivity of water of 3.0 dS m-1 reduces the chlorophyll synthesis and production of custard-apple. NPK recommendation of 100-125-125, 125-125-100 and 125-125-125% cause more damage to the cell membrane. Reduction in the quantum efficiency of custard-apple under salt stress is indicative of photoinhi-bitory damage. RESUMO No semiárido do Nordeste brasileiro, a alta concentração de sais encontrada nas águas destaca-se como um fator limitante para agricultura irrigada. Assim, a adubação com nitrogênio (N), fosforo (P) e potássio (K) é uma estratégia capaz de amenizar o estresse salino sobre as plantas. Neste contexto, objetivou-se com esta pesquisa avaliar os teores de pigmentos cloroplastídicos, a fluorescência da clorofila, o dano na membrana celular e a produção de pinha irrigadas com água de diferentes condutividades elétricas e adubadas com nitrogênio, fósforo e potássio. Os tratamentos foram distribuidos em blocos ao acaso, em esquema fatorial 2 x 8, com três repetições, sendo dois níveis de condutividade elétrica da água de irrigação - CEa (0,8 e 3,0 dS m-1) e oito combinações de adubação NPK (100-100-100; 100-100-125; 100-125-100; 100-125-125; 125-100-100; 125-100-125; 125-125-100 e 125-125-125% das doses recomemdadas de N-P2O5-K2O). A CEa de 3,0 dS m-1 diminuiu os teores de clorofila a e total, o número de frutos por planta, e eficiência fotoquímica, e aumentou os teores de carotenoides e o dano na membrana celular de pinha. A adubação com 100-125-125; 125-125-100 e 125-125-125% das dose recomendada de N-P2O5-K2O resultou em maior dano na membrana celular de pinha.

Garlic mustard [Alliaria petiolata (M. Bieb.) Cavara & Grande] is a biennial invasive plant commonly found in the northeastern and midwestern United States. Although it is not recommended to apply herbicides after flowering, land managers frequently desire to conduct management during this timing. We applied glyphosate and triclopyr (3% v/v and 1% v/v using 31.8% and 39.8% acid equivalent formulations, respectively) POST to established, second-year A. petiolata populations at three locations when petals were dehiscing and evaluated control, seed production, and seed viability. POST glyphosate applications at this timing provided 100% control of A. petiolata by 4 wk after treatment at all locations, whereas triclopyr efficacy was variable, providing 38% to 62% control. Seed production was only reduced at one location, with similar results regardless of treatment. Percent seed viability was also reduced, and when combined with reductions in seed production, resulted in a 71% to 99% reduction in number of viable seeds produced per plant regardless of treatment. While applications did not eliminate viable seed production, our findings indicate that glyphosate and triclopyr applied while petals are dehiscing is a viable alternative to cutting or hand pulling at this timing, as it substantially decreased viable A. petiolata seed production.

Physalis angulata is a medicinal plant with potential to treat several diseases due to the presence of secondary metabolites, such as phenolic compounds. The influence of the application of different abscisic acid (ABA) concentrations on the composition of phenolic compounds and gas exchange was evaluated on the Physalis angulata leaves. The experiment was conducted in a greenhouse in Cruz das Almas, Bahia, Brazil, with potted plants. At 45 days after sowing, the plants were separated into groups and the following treatments were applied: 0, 25, 50, 100 and 150 μmol L−1 of ABA. Two days after the treatments application, the gas leaf exchange (liquid photosynthesis, stomatal conductance, transpiration rate, mesophilic CO2 concentration and the relationship between atmospheric CO2 concentration and mesophilic CO2 concentration) between 9:00 and 11:00 was measured using an infrared gas analizer (IRGA). Four days after ABA spraying, some plants showed senescence symptoms, and therefore they were collected and taken to the stove until reached a constant dry mass. The total phenolics, caffeic acid, rutin, and trans-cinnamic were evaluated in response to the ABA. The ABA application increased the synthesis of total phenolic compounds up to 50 μmol L−1 concentration. The ABA application did not interfere with the caffeic acid synthesis. However, the rutin concentration increased regardless of ABA concentration that was applied and for trans-cinnamic acid, there was an increase up to the concentration of 100 μmol L−1. The ABA application caused stomatal closure and, consequently, the leaf gas exchange of Physalis angulata reduced.

The present work aimed to analyze the mineral nutrition of Physalis angulata L. under stress by aluminum in the nutrient solution. The treatments consisted of five different concentrations of aluminum in the nutrient solution (0, 0.04, 0.08, 0.12, and 0.16 mmol L−1) in the AlCl3 form. The plants were exposed to Al for 30 days. Subsequently, nutritional and aluminum analyses were performed on plant tissue. The data were submitted to analysis of variance (p

Establishment of alfalfa by interseeding it with corn planted for silage can enhance crop productivity but weed management is a challenge to adoption of the practice. Although a simple and effective approach to weed management would be to apply a glyphosate-based herbicide, concerns about herbicide resistance and limitations in available alfalfa varieties exist. Field experiments were conducted to compare the efficacy and selectivity of PRE, POST, and PRE followed by POST herbicide programs to a glyphosate-only strategy when interseeding alfalfa with corn. Experiment 1 compared PRE applications of acetochlor, mesotrione, S-metalochlor, metribuzin, and flumetsulam. Results indicate that acetochlor and metribuzin, and S-metalochlor used at a rate of 1.1 kg ai ha−1 were the most effective and selective PRE herbicides 4 wk after treatment (WAT), but each resulted in greater overall weed cover than glyphosate by 8 WAT. Experiment 2 evaluated applications of bentazon, bromoxynil, 2,4-DB, and mesotrione at early and late POST times. Several herbicides used POST exhibited similar effectiveness and selectivity as glyphosate, including early applications of bromoxynil (0.14 kg ai ha−1) and 2,4-DB (0.84 or 1.68 kg ai ha−1), as well as late applications of bromoxynil (0.42 kg ai ha−1), 2,4-DB (0.84 kg ai ha−1), and mesotrione (0.05 or 0.11 kg ai ha−1). A third experiment compared applications of acetochlor PRE, bromoxynil POST, and a combination of acetochlor PRE with bromoxynil POST. All treatments were effective and safe for use in this interseeded system, although interseeded alfalfa provided 65% to 70% weed suppression in corn planted for silage without any herbicide. Herbicide treatments had no observable impacts on corn and alfalfa yields, so weed management was likely of limited economic importance. However, weed competitiveness can vary based on several different factors including weed species, density, and site-specific factors, and so further investigations under different environments and conditions are needed.

A method based on the dispersive liquid–liquid microextraction for the pre-concentration of zinc in samples of Brazilian cachaca and determination by flame atomic absorption spectrometry (FAAS) was developed. The procedure is based on the injection of a mixture composed of carbon tetrachloride (extractor) and 5-(4-dimethylaminobenzylidene) rhodamine (complexing) in cachaca samples. The composition of the components of microextraction was univariable optimized. Posteriorly, a two-level fractional factorial design (26−2) was performed to evaluate the significance of the variables, pH, buffer concentration, centrifugation time, sonication time, NaCl concentration and temperature. Analysis of the Pareto graph showed that the pH, NaCl concentration and sonication time are statistically significant. These variables were optimized using the Doehlert matrix, which was obtained as better experimental conditions: pH, 9.0; %NaCl, 4% (m v−1); sonication time, 5.5 min. The precision expressed as relative standard deviation (RSD) was 3.43% for 20 μg L−1, the limit of detection was 0.11 μg L−1, and the limit of quantification was 0.33 μg L−1. The pre-concentration factor of the method was 28. The method was applied for the analysis of Brazilian sugarcane spirit, and the concentration of zinc ranged from 1.35 to 12.5 μg L−1.

Nickel catalysts were synthesized by the wet impregnation of three different supports: γ-Al2O3 and alumina promoted with either 10 wt % of MgO or 10 wt% of CaO. The catalysts were evaluated in butanol steam reforming at 500 °C, atmospheric pressure, GHSV of 500,000 h−1 and 10% v/v butanol in the feed. Both promoters decreased catalyst acidity and increased basicity. The catalyst promoted with MgO exhibited the lowest acidity (1.1 μmolNH3 m−2), whereas that promoted with CaO, the highest basicity (870.7 μmolCO2 m−2). The promotion with MgO led to the highest hydrogen yield (66%) and stability, associated with its highest nickel dispersion (3.4%), lowest acidity and lowest coke formation normalized by carbon converted (3.0 mmol L mol−1). The catalyst promoted with CaO presented the most severe deactivation, associated with its lowest dispersion (1.0%) and the highest amount of encapsulated coke (3.5 mmol L mol−1).

Pintoi peanut is a warm-season perennial legume that shows promise as a forage crop for the southeastern United States, however, little is known about the proper methods of weed management during establishment for this species. The objective of this study was to determine the ability of pintoi peanut to tolerate applications of PRE and POST herbicides during the year of and year after planting. The effects of herbicide treatments on percentage of visual estimates of injury and stand counts of pintoi peanut were investigated at Ona and Marianna, FL, in 2015 and 2016. All PRE herbicides did not result in significant injury or stand reduction. Pintoi peanut’s tolerance to POST herbicides was higher when plants were emerged for at least 2 wk prior to herbicide application. Stands of pintoi peanut that were planted the previous year appear to tolerate all herbicides examined in this work, except sulfosulfuron. Results of this study indicate that at the year of planting pintoi peanut is tolerant to PRE applications of pendimethalin, imazethapyr, and imazapic. Pintoi peanut appears to tolerate applications of 2,4-D, carfentrazone, imazapic and imazethapyr the year after planting at the rates utilized in this study. Future research should evaluate the effects of multiple herbicide applications and tank-mixes to obtain satisfactory weed control and selectivity in pintoi peanut swards.

Worldwide, medicinal plants and herbal medicines are widely consumed. The aim of this study was to determine macro- (Ca, K, Mg, Na, and P) and microelements (Al, As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sb, Se, Si, Sn, Sr, V, and Zn) in medicinal plants and herbal medicines: “globe artichoke” - Cynara scolymus L., “devil’s claw” - Harpagophytum procumbens D.C., and “espinheira santa” - Maytenus ilifolia (Mart) ex Reiss. Concentrations of 24 (essential and toxic potentially) elements in samples from Brazil were determined using a sequential optical emission spectrometer with inductively coupled plasma optical emission spectrometry (ICP OES) after acid digestion, assisted by microwave radiation. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used to carry out an exploratory analysis of samples. The elements were quantified (in μg/g): Al (20.24–1261.64), Ba (18.90–63.18), Ca (2877.6–19,957.40), Cr (0.28–1.38), Cu (4.16–21.99), Fe (8.54–627.49), K (1786.12–32,297.19), Mg (505.82–6174.52), Mn (0.40–205.64), Na (1717.23–18,596.45), Ni (< LoQ–0.99), P (35.12–2899.91), Se (1.52–3.71), Sn (1.53–12.43), Sr (52.33–84.31), V (< LoQ–0.24), and Zn (2.60–30.56). As, Cd, Co, Mo, Pb, and Sb, in all the investigated samples, were found to be below the limit of detection (LoD) and quantification (LoQ) values of ICP OES. These medicinal plants and herbal medicines can be sources of Ca, K, Mg, Na, P, Cu, Fe, Mn, Se, and Zn. All samples showed considerable levels of Al. PCA and HCA showed that the samples separated into two large groups.

A novel highly efficient photocatalyst composite BiFeO3/Fe3O4 has been synthesized by mechanosynthesis and applied to the degradation of Methylene Blue under visible light. Structural, optical and photocatalytic properties of the proposed photocatalyst composites are carefully investigated. The nanointerfaces, associated to ferrous Fe2+ ions of the Fe3O4 nanoparticles, improve the photocatalytic efficiency when compared with pure BiFeO3 or Fe3O4. The time required to the complete degradation of Methylene Blue solution is 40 min for the sample with 20% of Fe3O4 which is more than 7 times faster than the time required using BiFeO3 alone. Moreover, with the addition of H2O2 a complete degradation is achieved just after 10 min, which is faster than any other photocatalytic reaction reported for BiFeO3-based materials. This enhancement is assumed to be related to an electron drain process due to the difference between energy levels of the conduction bands of BiFeO3 and Fe3O4 combined with the direct Fenton-like process associated with the Fe2+ ions of the composites.

In the present work, solidified floating organic drop microextraction assisted by ultrasound is proposed as the preconcentration system for the determination of trace amounts of nickel, cobalt and copper by FAAS. The main parameters such as pH, concentration of TAN, extraction time, sample and organic phase volume and the nature of the organic solvent were optimized. This system has allowed the determination of nickel, cobalt and copper with a limit of detection (LOD) of 0.03, 0.04 and 0.03 μg g−1 and a limit of quantification (LOQ) of 0.10, 0.13 and 0.10 μg g−1. The precision is expressed as relative standard deviations (R.S.Ds) of 3.2, 2.8 and 2.6 for nickel, copper and cobalt, respectively. Accuracy was confirmed by determination of analytes in the standard reference materials, NIST SRM tomato leaves 1573a and NIST 1577 bovine liver samples, and spike tests, with recoveries ranging from 96 to 104%. The procedure was applied for nickel, cobalt and copper determination in tin oyster and fish samples.

Piperine and capsaicin are important molecules with biological and pharmacological activities. This study aimed to evaluate the cytogenotoxic and protective effect of piperine and capsaicin on Allium cepa cells. A. cepa roots were exposed to negative (2% Dimethylsulfoxide) and positive (Methylmethanesulfonate, MMS, 10 µg/mL) controls, and four concentrations (25-200 µM) of piperine or capsaicin (alone) or associated before, simultaneously or after with the MMS. Only the lowest concentration of piperine (25 µM) showed a protective effect because it was not genotoxic. Piperine and capsaicin were cytotoxic (50, 100 and 200 µM). Piperine (50 to 200 µM) caused a significant increase in the total average of chromosomal alterations of in A. cepa cells. For capsaicin, the genotoxic effect was dose-dependent with a significant increase for all concentrations, highlighting the significant presence of micronuclei and nuclear buds for the two isolates. In general, bioactive compounds reduced the total average of chromosomal alterations against damage caused by MMS, mainly micronuclei and/or nuclear buds. Therefore, the two molecules were cytotoxic and genotoxic at the highest concentrations, and did not have cytoprotective action, and the lowest concentration of piperine demonstrated important chemopreventive activity.

The pyridine carboxylic acid (PCA) herbicide family can exhibit differential activity within and among plant species, despite molecular resemblances. Aminocyclopyrachlor (AMCP), a pyrimidine carboxylic acid, is a recently discovered compound with similar use patterns to those of the PCA family; however, relative activity among PCAs and AMCP is not well understood. Therefore, the objective of this study was to quantify relative activity among aminopyralid, picloram, clopyralid, triclopyr, and AMCP in canola, squash, and okra using dose-response whole-plant bioassays. Clopyralid was less active than all other herbicides in all species and did not fit dose-response models. Aminopyralid and picloram performed similarly in squash (ED50= 21.1 and 23.3 g ae ha−1, respectively). Aminopyralid was 3.8 times and 1.7 times more active than picloram in canola (ED50= 60.3 and 227.7 g ha−1, respectively) and okra (ED50= 10.3 and 17.3 g ha−1, respectively). Triclopyr (ED50= 37.3 g ha−1) was more active than AMCP (ED50= 112.9 g ha−1) and picloram in canola. Aminocyclopyrachlor (ED50= 6.6 g ha−1) and triclopyr (ED50= 7.8 g ha−1) were more active in squash than aminopyralid and picloram. In okra, AMCP (ED50= 14.6 g ha−1) and aminopyralid (ED50= 10.3 g ha−1) performed similarly but were more active than triclopyr (ED50= 88.2 g ha−1). Herbicidal activity among AMCP and PCAs was vastly different despite molecular similarities that could be due to variable target-site sensitivity among species.

An evaluation of different elements (Be, Ga, In, Sc, and Y) as internal standards was performed to determine the content of Al, Ba, Co, Cr, Cu, Fe, Mn, Ni, Sr, Zn, Ca, Mg, Na, K in beer samples through microwave induced plasma optical emission spectrometry. The analytes were determined after simple dilutions of the samples with a 1.0 M nitric acid solution at a 1:4 ratio (sample: acid solution) with the addition of the IS. The analytical performance for each potential IS was established based on the limit of detection, limit of quantification, addition and recovery tests and accuracy obtained in the determination of each analyte. Each analyte responded differently when internal standardization was applied, and as such, the evaluation of each IS is important in the development of the method. In the presence of the recommended internal standard, the limit of detection varied, in μg L−1, from 0.23 to 4.6 for the microelements and between 10 and 620 for the macroelements. The limit of quantification, in μg L−1, was between 0.78 and 15.4 and between 30 and 970 for the microelements and macroelements, respectively. The precisions of the measurements, expressed as the relative standard deviation (n = 10; 0.50 and 3.0 mg L−1 of each analyte), were lower than 1.0% for all analytes. The proposed method was applied for the multi-element determination in commercial beer samples and the results were compared with those obtained by inductively coupled plasma optical emission spectrometry after sample digestion.

Background Antenatal hydronephrosis (ANH) affects ∼1–5% of pregnancies. The aim of this study was to develop a clinical prediction model of renal injury in a large cohort of infants with isolated ANH. Methods This is a longitudinal cohort study of 447 infants with ANH admitted since birth between 1989 and 2015 at a tertiary care center. The primary endpoint was time until the occurrence of a composite event of renal injury, which includes proteinuria, hypertension and chronic kidney disease (CKD). A predictive model was developed using a Cox proportional hazards model and evaluated by C-statistics. Results Renal pelvic dilatation (RPD) was classified into two groups [Grades 1–2 (n = 255) versus Grades 3–4 (n = 192)]. The median follow-up time was 6.4 years (interquartile range 2.8–12.5). Thirteen patients (2.9%) developed proteinuria, 6 (1.3%) hypertension and 14 (3.1%) CKD Stage 2. All events occurred in patients with RPD Grades 3–4. After adjustment, three covariables remained as predictors of the composite event: creatinine {hazard ratio [HR] 1.27, [95% confidence interval (CI) 1.05–1.56]}, renal parenchyma thickness at birth [HR 0.78(95% CI 0.625–0.991)] and recurrent urinary tract infections [HR 4.52 (95% CI 1.49–13.6)]. The probability of renal injury at 15 years of age was estimated as 0, 15 and 24% for patients assigned to the low-risk, medium-risk and high-risk groups, respectively (P Conclusion Our findings indicate an uneventful clinical course for patients with Society for Fetal Urology (SFU) Grades 1–2 ANH. Conversely, for infants with SFU Grades 3–4 ANH, our prediction model enabled the identification of a subgroup of patients with increased risk of renal injury over time.

In this paper, studies on the preparation and properties of barium sodium titanate niobate and poly(vinylidenefluoride) (PVDF) bulk composites are reported. SEM images show ceramic particles incorp...

In this work, we have studied the microscopic, ferroelectric, magnetic and microstructural characteristics of cobalt ferrite/barium titanate core–shell magnetoelectric nanocomposites. Magnetoelectr...

The combination of the extraction induced by microemulsion-breaking (EIMB) and preconcentration using the solid-phase extraction (SPE) using magnetic nanoparticles (MNP) for determination of Cd, Cr, Cu and Pb in gasoline samples by energy dispersive X-ray fluorescence spectrometry (EDXRF) is proposed. The procedure was based in the formation of a three components microemulsion: gasoline as organic phase, n-propyl alcohol as an emulsifier and 0.01 mol L−1 HNO3 as aqueous phase. After formation of the microemulsion, tris/nitric acid buffer (0.1 mol L−1, pH 8.5) was used for the microemulsion breaking and adjust the pH simultaneously. Subsequently, an amount of CoFe2O4 nanoferrite was added to the medium for the retention and preconcentration of the species of interest present in the aqueous phase of the broken emulsion. After a contact time between the nanoparticle and the mixture, the solid phase was separated from the supernatant with the aid of a magnet and, after drying, the determination of the analytes was performed directly on the solid support (nanoferrite) by EDXRF. To guarantee the better extraction conditions, some experimental variables were investigated. The recommended proportion for the microemulsion formation was 65% (v v−1) n-propyl alcohol, 20% (v v−1) gasoline, and 15% (v v−1) nitric acid solution. For the solid phase extraction, 100 mg of nanoferrite and a contact time of 10 min were recommended. Enrichment factors between 10 and 470 times were found for the analytes. The limits of detection obtained by the proposed method were 24, 2.8, 16 and 9.7 μg L−1 for Cd, Cr, Cu and Pb, respectively. The precisions for determination of each element were expressed as relative standard deviations (RSD) using standard solutions containing 0.2 and 0.4 mg L−1 of each analyte and were between 2.0 and 8.1%. The developed method was applied in the determination of Cd, Cr, Cu and Pb in gasoline samples.

This research was carried out aiming at evaluating the effects of nitrate and ammonium ions on nutrient accumulation, biochemical components and yield of Italian zucchini (cv. Caserta) grown in a hydroponic system under salt stress conditions. The experiment was carried out in a greenhouse utilizing an experimental design in randomized blocks, arranged in a 2 x 5 factorial scheme, with 4 replications. The treatments consisted of two forms of nitrogen (nitrate - NO3- and ammonium - NH4+) and 5 electrical conductivity levels of irrigation water (ECw) (0.5, 2.0, 3.5, 5.0 and 6.5 dS m-1). The analysis of the results indicated that supply of N exclusively in NH4+ form promotes greater damage to the leaf membrane and reduction in accumulation of macronutrients and higher Na+/K+, Na+/Ca++ and Na+/Mg++ ratios in the shoots of zucchini plants. Electrical conductivity of irrigation water above 2.0 dS m-1 reduces the accumulation of nutrients in shoot and yield of Italian zucchini plant. The toxicity of NH4+ under Italian zucchini plants overlap the toxicity of the salinity, since its fertilization exclusively with this form of nitrogen inhibits its production, being the NO3- form the most suitable for the cultivation of the species. Resumo Este trabalho foi desenvolvido com o objetivo de avaliar os efeitos dos íons nitrato e amônio sobre o acúmulo de nutrientes e produção da abobrinha italiana (cv. Caserta) cultivada em sistema hidropônico sob estrese salino. O experimento foi conduzido em casa de vegetação utilizando o delineamento experimental em blocos casualizados, arranjados em esquema fatorial 2 x 5, com 4 repetições. Os tratamentos foram constituídos de duas formas de nitrogênio (nitrato - NO3- e amônio - NH4+) e cinco níveis de condutividade elétrica da água de irrigação (CEa) (0,5; 2,0; 3,5; 5,0 e 6,5 dS m-1). As análises dos resultados indicaram que suprimento de N exclusivamente em forma de NH4+ promove maiores danos na membrana foliar e redução no acúmulo de macronutrientes e maiores relações Na+/K+, Na+/Ca++ e Na+/Mg++ na parte aérea das plantas de abobrinha. A irrigação com água a cima de 2,0 dS m-1 reduz o acúmulo de nutrientes na parte aérea das plantas e a produção de abobrinha. A toxicidade do NH4+ sob abobrinha italiana sobrepõe-se à toxicidade da salinidade, pois a fertilização exclusiva com esta forma de nitrogênio inibe sua produção, sendo a forma NO3- a mais adequada para o cultivo da espécie.

Interactions of glycan-specific epitopes to human lectin receptors represent novel immune checkpoints for investigating cancer and infection diseases. By employing a multidisciplinary approach that combines isothermal titration calorimetry, NMR spectroscopy, molecular dynamics simulations, and X-ray crystallography, we investigated the molecular determinants that govern the recognition of the tumour and pathogenic glycobiomarker LacdiNAc (GalNAcβ1-4GlcNAc, LDN), including their comparison with the ubiquitous LacNAc epitope (Galβ1-4GlcNAc, LN), by two human immune-related lectins, galectin-3 (hGal-3) and the macrophage galactose C-type lectin (hMGL). A different mechanism of binding and interactions was observed for the hGal-3/LDN and hMGL/LDN complexes, which explains the remarkable difference in the binding specificity of LDN and LN by these two lectins. The new structural clues reported herein are fundamental for the chemical design of mimetics targeting hGal-3/hMGL recognition process.

Basil is an edible, aromatic plant, which makes the study of the ecotoxicity of metals in plant metabolism relevant. Given the above, the objective of this study was to evaluate the effects of metals, aluminum, lead, and cadmium, in the synthesis of phenolic compounds and in the dry mass of basil plants (O. basilicum L.) grown in a hydroponic system. The plants were subjected to four different concentrations of cadmium (0.2, 0.6, 1.2, and 1.8 mmol L-1), lead and aluminum (0.04, 0.08, 0.12, and 0.16 mmol L-1), and compared with the control. After desiccation of the plant material, the total dry mass was obtained and then, hydroethanolic extracts (43% distilled water and 57% ethanol) were made for biochemical analyzes, which consisted of the determination of caffeic acid (CA) and rosmarinic acid (RA) by high performance liquid chromatography analysis with a diode detector (HPLC-DAD); total phenolics (TP) and total flavonoids (TF) by spectrophotometry. The data were submitted to analysis of variance and multivariate analysis (principal component analysis-PCA and hierarchical cluster analysis-HCA) was applied for data association. The phenolic compounds showed a high positive correlation with each other, and the total dry mass showed low and negative correlations with the analyzed variables. The results showed that the metals aluminum, lead, and cadmium promoted a stress condition in basil plants, which resulted in the reduction of the dry matter mass and an increase in the synthesis of phenolic compounds, according to the type and concentration of the metal.

Four cationic chiral amino acid-based surfactants, cis- and trans-1 and cis- and trans-2, have been studied as DNA-condensing agents with enhanced properties and the absence of cell toxicity. The polar head of the surfactant is made of a cyclobutane β-amino acid in which the amino group is a hydrochloride salt and the carboxyl group is involved in an amide bond, allowing the link with hydrophobic C12 (surfactant 1) or C16 (surfactant 2) chains. The ability of these surfactants to condense DNA was investigated using a dye exclusion assay, gel electrophoresis, and circular dichroism and compared with the well-studied dodecyltrimethylammonium bromide (DTAB) and cetyltrimethylammonium bromide (CTAB). The surfactant with the longest chain length and the trans stereochemistry (trans-2) was found to be the most efficient in condensing the DNA, including CTAB. Surfactant cis-2 was found to be less efficient, probably due to its poorer solubility. The β-amino acid surfactants with the shorter chain length behaved similarly, such that the cis/trans stereochemistry does not seem to play a role in this case. Interestingly, these were also found to induce DNA condensation for the same concentration as trans-2 and CTAB but showed a lower binding cooperativity. Therefore, a longer alkyl chain only slightly improved the effectiveness of these surfactants. Further, atomic force microscopy revealed that they compact DNA into small complexes of about 55-110 nm in diameter

This work describes the development of an HPLC-FLD methodology for the separation of five fluoroquinolones (ciprofloxacin, enrofloxacin, sarafloxacin, norfloxacin and levofloxacin) followed by optimization of the DLLME process for the clean-up and preconcentration of enrofloxacin in samples of seawater and river water. The mobile phase used for the chromatographic separation consisted of methanol: phosphate buffer (NaHPO4 H2O 0.04 M pH 3 with H3PO4 85 %), gradient eluted at a ratio of 20:80 (v:v). The mobile phase flow was maintained at 1.2 mL min-1. For the ultrasonic-assisted dispersive liquid liquid microextraction (UA-DLLME), the following conditions were used: 8 mL of sample with pH adjusted to 8, extraction solvent: 500 μL of chloroform, dispersive solvent: 500 μL of acetonitrile; samples were vortexed and sonicated for 2 minutes, each. The enrichment factor (EF) was 54.7 and the recovery was 70 %, achieving a limit of detection (LOD) of 0.11 μg L-1. Repeatability and intermediate reproducibility presented values of relative standard deviation (RSD) lower than 2 %. Finally, the optimized method was applied to the analysis of water and enrofloxacin was detected in both water samples with a concentration of 0.20 μg L-1 in the river and 0.12 μg L-1 in the seawater. However, recovery tests performed to evaluate the water matrices' effects on the extraction performance, presented recoveries of 72±6.1 for river water and 27±8.3 for seawater. These results demonstrate that hereby developed method is only suitable for water samples with a low salinity content. published

In this work we study the coupling between ionization and conformational properties of two IDPs, histatin-5 and β-amyloid 42, in the presence of neutral and charged crowders. The latter is modeled to resemble bovine serum albumin (BSA). With this aim, semi-grand canonical Monte Carlo simulations are performed, so that the IDP charge is a dynamic property, undergoing protonation/deprotonation processes. Both ionization properties (global and specific amino acid charge and binding capacitance) and radius of gyration are analyzed in a large range of pH values and salt concentrations. Without crowder agents, the titration curve of histatin-5, a polycation, is salt-dependent while that of β-amyloid 42, a polyampholyte, is almost unaffected. The salt concentration is found to be particularly relevant at pH values where the protein binding capacitance (directly linked with charge fluctuation) is larger. Upon addition of neutral crowders, charge regulation is observed in histatin-5, while for β-amyloid 42 this effect is very small. The main mechanism for charge regulation is found to be the effective increase in the ionic strength due to the excluded volume. In the presence of charged crowders, a significant increase in the charge of both IDPs is observed in almost all the pH range. In this case, the IDP charge is altered not only by the increase in the effective ionic strength but also by its direct electrostatic interaction with the charged crowders.

A sample pretreatment based on an extraction process by emulsion breaking for multi-element determination in edible oils was developed. The determination of eight trace elements (Al, Ba, Cu, Cr, P, Ni, Ti, and Zn) was carried out by microwave-induced plasma optical emission spectrometry (MIP OES) after the extraction procedure. A D-optimal mixture experimental design was used to obtain the best experimental conditions for the extraction induced by emulsion breaking (EIEB). The proportion of HNO3 solution, Triton X-100 solution and sample was evaluated in a multivariate manner. The best recovery efficiency was obtained with 1.0 mL of 30% (v/v) HNO3, 1.0 mL of 30% (w/v) Triton-X 100 and 3.0 mL of the sample. The precisions, established as the relative standard deviation (RSD, %), were better than 2.5% for all analytes. The developed method was applied to the analysis of commercial vegetable oils with low limits of detection and good precision. Fil: Carneiro, Angélica Fagundes. Universidade Federal do Recôncavo da Bahia; Brasil Fil: Carneiro, Candice Nóbrega. Universidade Federal do Recôncavo da Bahia; Brasil Fil: Pires, Laís de N.. Universidade Federal da Bahia; Brasil Fil: Teixeira, Leonardo S. G.. Universidade Federal da Bahia; Brasil Fil: Azcarate, Silvana Mariela. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; Argentina Fil: Dias, Fabio de Sousa. Universidade Federal da Bahia; Brasil

Melipona quadrifasciata anthidioides is a species of stingless bee popularly known in Brazil as "mandacaia". Products derived from bees for food and therapeutic uses, have stimulated the evaluation of the chemical composition of geopropolis. Concentrations of 24 essential and potentially toxic elements were determined in geopropolis samples, using a sequential optical emission spectrometer with inductively coupled plasma (ICP OES) after microwave-assisted acid digestion. Principal component analysis (PCA) and Hierarchical cluster analysis (HCA) were used to carry out an exploratory analysis of the samples. The following elements were quantified (in mg Kg-1): Al (320,414.40-36,911.1), As (

SnO particles were synthesized by an alkali-assisted hydrothermal and microwave methods. The aqueous-based reactions were carried out at pH ~ 8, under inert atmosphere (Ar). The reactions were taken under different times, and a full XRD structural analysis was made to evaluate the conversion from the Sn6O4(OH)4 intermediate to SnO particles. Williamson-Hall analysis showed that the size and strain of the SnO particles were time and route treatment dependent. Microwave heating yielded a single tetragonal SnO phase after 1 h of thermal treatment, and TEM images revealed spherical-shaped SnO nanoparticles with an average size of 9(1) nm. While by the hydrothermal treatment single SnO phase was obtained only after 4 hours, yielding non-uniform and elongated particles with sub-micrometric size. A dissolution-recrystallization process was taken into account as the mechanism for SnO particles formation, in which hydroxylated complexes, Sn2(OH)6−2, then condense to form the oxide. The time-shorting reaction provided by the microwave-assisted synthesis may be attributed to better heat distribution.

This study proposes a method based on solid-phase extraction using a minicolumn with sugarcane bagasse for pre-concentration uranium in water samples. The first optimization step was used factorial design in two levels (25) for the preliminary assessment of factors: elution flow, sample flow, pH, buffer concentration, and eluent concentration. From this design, it was found that all variables showed significant influence. In the second stage, using the Doehlert design with 5 variables, the optimal conditions were determined: pH 8.3, flow elution 5.5 mL min−1, buffer concentration 0.045 mol L−1, sample flow 5.5 mL L−1, and eluent solution (ascorbic acid 0.6% w/v in medium of hydrochloric acid at a final concentration of 0.06 mol L−1). The method was applied to the determination of uranium with a detection limit (LD) of 0.41 μg L−1 and quantification (LOQ) of 1.40 μg L−1, Relative standard deviation (RSD) 2.5 and 1.3% uranium concentration of 20 and 60 μg L−1, respectively. The factor of pre-concentration for the system is 46 for a sample volume of 50 mL. The accuracy was confirmed by the spike test. The procedure was applied for the determination of uranium in tap water, well water, and human consumption; the samples were collected in the municipalities of Caetite, Cruz das Almas, Itabuna, Aramari-BA, and seawater samples from Todos os Santos Bay. Uranium concentrations were found in the analyzed samples varying from 7.0 to 16.5 μg L−1.

In this work the dispersive liquid-liquid microextraction technique (DLLME) is presented as an important alternative to the classical extraction methods and was used to extract and concentrate estrogens’ before its quantification by HPLC in environmental water samples. For the evaluation of the analytical methodology, the following conditions were used: sample volume 8 mL, extraction solvent 200 μL of chlorobenzene, and dispersive solvent 2000 μL of acetone. The enrichment factor (EF) was 140 for estrone, 202 for 17β-estradiol (E2), and 199 for 17α-ethinylestradiol (EE2). Limit of detection was 20 ng L−1 for E1, 3.1 ng L−1 for E2, and 2.7 ng L−1 for EE2. Repeatability and intermediate reproducibility presented values of relative standard deviation lower than 10%. Finally, recovery tests were performed to evaluate the water matrices’ effects on the extraction performance, resulting in recoveries between 76 and 110% in surface water and between 84 and 109% in wastewater.

This paper discusses 286 proposals and reports of Green Chemistry (GC) teaching experiences, in papers of the Journal of Chemical Education (JCEd) until 2019. The analysis was based on previous categories: source-problem, paper focus, subjects/area of knowledge, target groups, GC contents, type of approach and purpose(s) of the proposal. A list of possible characteristics of each category served as an example to compare with the information resulting from the analyses, and thus improve the discussions. In 127 papers, GC and its teaching were associated, albeit generally, with the theme of sustainability/sustainable development, which points to its potential to face environment-related aspects of chemistry in teaching. A systemic vision in the interconnection between GC and sustainability/sustainable development appeared more explicitly in 39 papers up to 2019. So far, the analysis highlights a certain reproduction of traditional chemistry teaching, and little evidence of the particularities of GC teaching. Despite the intention of inserting GC into chemistry teaching, proposals for its incorporation are often made superficially, more as an addendum or an extra quality than a specific goal. More methodological detail of the experiments carried out is needed to help in the dissemination of GC in the training curriculum of chemists. The discussions and reports on teaching approaches based on Systems Thinking showed the opening of a promising new methodological challenge within this theoretical paradigm.

The chili pepper is highly valued for its pungency and nutritional value, in addition to being a good source of phenolic compounds. Several factors affect the production of phenolics in the plant, including plant regulators. In this context, the present work aims to evaluate the influence of ABA, GA3, and SA in the production of phenolic compounds in Capsicum frutescens. It was applied 10 mmol L−1 of ABA, 144 mmol L−1 of GA3, 2000 mmol L of SA−1 and the control (C) (solution without regulators) in fruits of C. frutescens. The results show that chili pepper presented a good variety of phenolics, ranging from phenolic acids (benzoic and cinnamic acids) to flavonoids (flavonols and flavan-3-ols) and that phenolic concentrations were significantly altered in fruits treated with GA3, ABA and SA compared to control fruits. In addition, the PCA and HCA separated the samples into three groups, C, ABA, and a group with GA3 and SA, with the ABA group having the highest phenolic content and the C group the lowest. Plant regulators (GA3, ABA and SA) influence the synthesis of phenolic compounds in C. frutescens fruits.

Macroporous silicon layer was passivated by chemical oxidation and then polyaniline was deposited chemically within the porous structure in order to fabricate a heterostructure to be used as chemical sensor. The structural characterization of this device by scanning electron microscopy reveals the effectiveness of the chemical method for polyaniline deposition in oxidized porous matrix. The analysis by AT-FTIR and Raman spectroscopy shows that polyaniline was deposited in its emeraldine state, which is the most conductive phase, forming a well-defined replica of the porous structure. However, according to the EDS analysis, this polymer layer is non-homogeneous in depth. This feature was also confirmed by electrical measurements of current-voltage and electrochemical impedance at different points between the polymer surface and silicon substrate. In spite of this fact, the immersion of this structure in an ethanolic solution containing low amounts of naphthalene shown that this structure is excellent to be used as chemical sensor for the detection of low concentrations of naphthalene in the order of 30 ppb.

Made available in DSpace on 2022-04-30T13:09:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-01-01 With the advent of new implantation technologies of sugarcane crop, the aim of this study was to evaluate the selectivity of herbicides in pre-budded cultivars of sugarcane seedlings. With the formation of seedlings from a gem of high sanity in tubes with substrates, seedlings, with an average height of 20 cm, were transplanted to 12 L pots filled with soil. The experimental design was a completely randomized factorial arranged in a (3x8), being the cultivars, CTC 7, CTC 14 and RB966928; and the herbicides (g ha-1): ametryn + trifloxysulfuron-sodium (1280 + 32.4); imazapic (150); halosulfuron (150); isoxaflutole (90); ametryn (5000); ametryn + clomazone (1500 + 1000) and amicarbazone (1500), applied 10 days after transplanting; and a control without application. The three cultivars of sugarcane visually studied responded differently to the application of herbicide treatments tested, being the herbicides ametryn + trifloxysulfuron, imazapic, halosulfuron and ametryn which caused less phytotoxicity. However, when confronting the other parameters analyzed, it was observed that ametryn + trifloxysulfuron, isoxaflutole, ametryn, ametryn + clomazone and amicarbazone for CTC7 cultivar, ametryn + clomazone and amicarbazone for CTC14 and amicarbazone for RB966928, caused loss to the initial development of the crop. São Paulo State University University of Florida São Paulo State University

In the present work the influence of milling process below 173 K (cryomilling) on the nanostructuration of BiFeO3 powders, synthesized by fast-firing thermal treatment allied to high-energy ball milling, is evaluated as function of milling time as well as balls size/mass ratio. The influence of the cryomilling process on the structural and magnetic properties of BiFeO3 powders is investigated and the key role of the crystallite size on the magnetic response is evidenced. The results show a strong nonlinear magnetic response, which is governed by the crystallite size while induced strain does not play an important role.

In this manuscript, an innovative and bioactive polyvinylidene fluoride-biphasic calcium phosphate (PVDF-BCP) ferroelectric composite was synthesized and characterized. FTIR investigations reveal t...

The present article describes the development of an ultrasonic assisted extraction of phenolic compounds in Physalis angulata and determination of caffeic acid, rutin, catechin and trans-cinnamic acid by HPLC DAD. The mixtures were composed of extractor solvent and its ratio optimized using a mixture design. Doehlert matrix was used to optimize the extractor solvent volume and sonication time while using total phenolics as analytical response. The optimized conditions for the extractor solvent were the ratio of: 57% water, 35% ethanol and 8% methanol. The best experimental conditions for ultrasound were a sonication time of 10 min and extractor volume of 15 mL. The limit of detection varied from 5.0 to 30 μg L−1. The methods precision was expressed as relative standard deviation (RSD) and presented values lower than 3.0% for all analytes. The accuracy was evaluated using spike test with recoveries between 91% and 107%. The method was applied for the determination of caffeic acid, rutin, catechin and trans-cinnamic in four samples of Physalis angulata aerial parts and the concentration varied from 15.5 to 22.5 μg g−1 for catechin, from 25.0 to 32.5 μg g−1 for caffeic acid, 75.6 to 88.2 μg g−1 for rutin and varied from 23.5 to 110.7 μg g−1 for trans-cinnamic acid.

A ceramic/polymer biocomposite with high potential for multifunctional practical applications in bone tissue engineering was synthesized by using a well-known piezoelectric polymer, polyvinylidene fluoride (PVDF), and a high bioactive biphasic calcium phosphate (BCP) ceramic obtained from recycled fish bones. High-bioactivity was observed for the PVDF-BCP composite when it was subjected to conditions that simulate the animal body once a very thick apatite layer (9 μm) was grown on its surface in an immersion experiment (7 days) in simulated body fluid. The structural characteristics of the PVDF-BCP composite showed similarities with highly bioactive young animal bones, overlapped with PVDF polymorphic phases. Mechanical tests revealed properties very similar to those of the human bone tissue with a resistance strength reaching 80 MPa. Together, all these factors indicated a very promising material for application in osseous implants/replacement with postoperative recovery controlled/accelerated by external stimuli. Resumo Um biocompósito cerâmico/polimérico com alto potencial para aplicações práticas multifuncionais em engenharia de tecidos ósseos foi sintetizado usando o conhecido polímero piezoelétrico, fluoreto de polivinilideno (PVDF), e a cerâmica altamente bioativa, fosfato de cálcio bifásica (BCP), obtida a partir de ossos de peixes reciclados. Uma alta bioatividade foi observada no compósito PVDF-BCP quando este foi submetido a condições que simulam um corpo animal. De fato, uma camada de apatita muito espessa (9 μm) cresceu em sua superfície no experimento de imersão (7 dias) em fluido corpóreo simulado (SBF). As características estruturais do compósito PVDF-BCP mostraram semelhanças com ossos de animais jovens, altamente bioativos, sobrepostos com fases polimórficas de PVDF. Ensaios mecânicos revelaram propriedades muito semelhantes às do tecido ósseo humano, com uma resistência à compressão atingindo 80 MPa. Juntos, todos esses fatores indicaram um material muito promissor para aplicação em implantes e/ou substituições ósseas com recuperação pós-operatória controlada/acelerada por estímulos externos.

The title compound, C12H10N4O, comprises a central 1,2,3-triazole ring (r.m.s. deviation = 0.0030 Å) flanked by N-bound 4-cyanophenyl and C-bound acetyl groups, which make dihedral angles of 54.64 (5) and 6.8 (3)° with the five-membered ring, indicating a twisted molecule. In the crystal, the three-dimensional architecture is sustained by carbonyl-C=O...π(triazoyl), cyano-C[triple-bond]N...π(triazoyl) (these interactions are shown to be attractive based on non-covalent interaction plots) and π–π stacking interactions [intercentroid separation = 3.9242 (9) Å]. An analysis of the Hirshfeld surface shows the important contributions made by H...H (35.9%) and N...H (26.2%) contacts to the overall surface, as well as notable contributions by O...H (9.9%), C...H (8.7%), C...C (7.3%) and C...N (7.2%) contacts.

Evaluation of gadolinium enrichment in Gadolinia ( Gd 2 O 3 ) burnable poison fuel rods was performed for a model of PWR Angra-2 reactor fuel assembly. A parametric study of the effect of 155 Gd enrichment on neutronic performance was investigated during burn-up for a proposed very low gadolinium design (VLowGad-FA) having 1% of Gadolinia in weight fraction. Low fraction gadolinium designs enable the Angra-2 reactor to use its licensed limit of 235 U to its maximum potential, that is 4.25%, with better reactivity behavior for some cases. Thermal transport performance of irradiated fuel was followed through estimation of inter-assembly peak pin power during burn-up. Results showed that Gd enriched design would behave very similar to LowGad assembly in terms of controlling local core power. It was confirmed in the neutronic context that low gadolinium design provides fuel cycle economic benefits while supporting longer cycle operation. It was estimated savings of 18 effective full power days if LowGad (2.0% Gadolinia, 4.25% 235 U ) is used in place of refGad (7.0% Gadolinia, 2.90% 235 U ). Respect the proposed design, savings are up to 41 effective full power hours if the burnable poison fuel rod VLowGad (1% Gadolinia, 99% 155 Gd ) is used in place of the commercial LowGad. The break-even point for Gd-155 enrichment cost for VLow155Gd99 fuel assembly was calculated to be 371 US$/gram-Gd-155 based in year 2018 prices of MWe for Angra-2.

γ-Hydroxybutyric acid (GHB) is an endogenous compound with a historical use, both in licit and illicit terms. Importantly, the post-mortem behavior of GHB has been studied due to the possibility of using this compound as a biomarker for estimating the post-mortem interval (PMI). However, the post-mortem behavior of the recently discovered glucuronated GHB metabolite (GHB-GLUC) has not been studied. Nevertheless, GHB-GLUC may also have potential both to assist in PMI determination and also to increase the window of detection of GHB consumption. In this work, for the first time, a reliable method using GC–MS/MS for the quantification of GHB-GLUC in whole blood samples was developed and validated, with a simple, fast and cheap sample pretreatment. The method proved to be specific, precise, linear in a work range between 200 and 5000 ng/mL, with LOD and LOQ of 52.65 ng/mL and 200 ng/mL, respectively, and an extraction recovery of 51%. Furthermore, the method was applied to a set of real post-mortem blood samples non-related with GHB intoxication and the obtained results were also discussed.

In this study, a procedure for the pre-concentration and determination of cadmium in food samples by flame atomic absorption spectrometry (FAAS) was developed based on ultrasound-assisted emulsification microextraction with solidification of floating organic droplet (USAEME-SFO) using 1-(2-thiazolylazo)-p-cresol (TAC) as complexing reagent. The limits of detection and quantification were 0.60 μg L−1 and 2.0 μg L−1, respectively. The method's precision was expressed as relative standard deviation of 3.0% (10 μg L−1). Accuracy was evaluated through certified reference sample analysis of tomato leaves (SRM 1573a), rice flour (NIES 10b), and Drinking Water Standard 1071, and the recovery test results ranged from 90 to 100%. The procedure was applied for the determination of cadmium in corn flour, bean, cabbage, and mineral water samples in which the analyte concentration ranged from 0.30 to 2.1 μg g−1 for food samples and from 0.30 to 0.46 μg L−1 for water samples.

A Strain-related defects, such as dislocations, and their effects on physical properties are well known for metallic materials as well as for oxide thin films. However, little to no research regards these effects on oxide nanoparticles. Herein, we deeply explore the effects of dislocations on the magnetic properties of high-strained BiFeO3 nanoparticles obtained by high-energy cryo-milling. Several structural changes such as superexchange angle, Fe-O-Fe bond length and FeO6 octahedral distortions are confirmed. Besides, the introduction of high dislocation density and reduced crystallite size gives rise to an unusual magnetic behavior changing the magnetic hysteresis from an antiferromagnetic-like to a weak-ferromagnetic-like loop, suggesting that high concentration of dislocations in BiFeO3 nanoparticles can be used to directly control its magnetic properties.

In the present work, a method was developed, optimized, and validated for the determination of aluminum, manganese, lead, copper, cadmium, and zinc by microwave-induced plasma optical emission spectrometry of wine samples from the Sao Francisco Valley, northeastern Brazil. The samples were subjected to a sonochemical treatment aiming at the degradation of the sample matrix. To optimize the analytical procedure, initially, a two-level fractional factorial design was used to study five experimental variables and determine which ones significantly affected the analytical response. In a second step, the significant variables were optimized using the Doehlert matrix as the response surface methodology and the desirability function as a strategy to optimize multiple responses. The optimum conditions established were concentrations of nitric acid (2.3 mol L−1) and hydrogen peroxide (9%). The developed method is simple, fast, and precise, has a low operational cost and low limits of detection and quantification. The accuracy confirmed by spike tests with recoveries ranging from 104 to 118% and comparative analysis of the results obtained using the proposed method and digestion total procedure. The method was applied for multi-element determination in three wine samples.

Bacuri (Platonia insignis Mart) is a species from the Clusiaceae genus. Its fruit pulp is commonly used in South America in several food products, such as beverages, ice cream and candies. Only the pulp of the fruit is used, and the peels and seeds are considered waste from these industries. As a trioxygenated xanthone source, this species is of high interest for bioproduct development. This work evaluated the mesocarp and epicarp of bacuri fruits through different extraction methods and experimental conditions (pH, temperature and solvent) in order to determine the most effective method for converting this agro-industrial waste in a value-added bioproduct. Open-column procedures and HPLC and NMR experiments were performed to evaluate the chemical composition of the extracts, along with total phenols, total flavonoids and antioxidant activities (sequestration of the DPPH and ABTS radicals). A factorial design and response surface methodology were used. The best extraction conditions of substances with antioxidant properties were maceration at 50 °C with 100% ethanol as solvent for mesocarp extracts, and acidic sonication in 100% ethanol for epicarp extracts, with an excellent phenolic profile and antioxidant capacities. The main compounds isolated were the prenylated benzophenones garcinielliptone FC (epicarp) and 30-epi-cambogin (mesocarp). This is the first study analysing the performance of extraction methods within bacuri agro-industrial waste. Results demonstrated that shells and seeds of bacuri can be used as phenolic-rich bioproducts obtained by a simple extraction method, increasing the value chain of this fruit.