Asphaltene aggregation mechanism is still a nebulous and controversial issue. Many authors argue that the aggregation of its components is due to π-stacking interactions, nonetheless, alkyl chains, heteroatoms, and even acidic groups are also constituents of asphaltenes and can play an important role in the chemistry of asphaltene. Excimers from pyrene are easily detected by fluorescence and were used in the current study to probe the effect of the side chain on the π-stacking capacity of pyrene. Pyrene was acylated with acyl chains varying from two to twelve carbon atoms, and the effect of the variation of the acyl chain length on excimer formation was followed by fluorescence emission spectroscopy. The results revealed that as the side chain grows from two to twelve carbon atoms the excimer/monomer ratio decreases and the excimer heat of formation drops from ΔH = -6.00 to -1.29 kcal mol-1. Further, the crystal structure of octanoyl pyrene (PC8) indicates that in the crystal structure, the aromatic moiety faces the acyl chain. This result was corroborated by density functional theory (DFT) calculations. Finally, the results were compared with two different asphaltenes and indicate that π-stacking cannot be assumed as the main driving force for asphaltene aggregation. issue πstacking π stacking interactions nonetheless heteroatoms spectroscopy excimermonomer monomer 6.00 600 6 00 -6.0 1.29 129 1 29 -1.2 mol1. mol1 mol 1. mol-1 Further PC8 PC (PC8 DFT (DFT calculations Finally 6.0 60 0 -6. 1.2 12 2 -1. mol- (PC 6. -6 -1 -

Biodiesel is obtained from the alcoholysis of triglycerides and has been used as a renewable alternative to diesel. Though the methanolysis of triglycerides in the presence of MeONa catalyst has been widely used, searching for alternatives that may improve the competitiveness of the production chain is still a challenge. The aim of this work was to evaluate sodium glyceroxide as a catalyst in the methanolysis of soy oil. Sodium glyceroxide was obtained from glycerol and NaOH in ethanol, and characterized by thermogravimetric analysis (TGA), X-ray powder diffraction (XRD) and, Fourier transform infrared (FTIR) spectroscopy. The transesterification reaction was optimized after two sets of experiments based on the Doehlert matrix experimental design. In the first one, the influence of the molar ratio of methanol/triglyceride, and the amount of catalyst (m/m with respect to the triglyceride) were studied. In the second set, the temperature, and the reaction time were studied. The best conditions were found as 12:1 molar ratio, 2% of catalyst, 50 ºC, and 60 min. The conditions were applied in the transesterification of canola and sunflower oils, and tallow. All the biodiesels were obtained with an ester content superior to 98%, free from methanol and triglycerides. Specific mass, viscosity, and pour point were determined and met the international specifications. diesel challenge oil ethanol TGA, TGA , (TGA) Xray X ray XRD (XRD FTIR (FTIR spectroscopy design one methanoltriglyceride triglyceride methanol/triglyceride m/m mm m studied set temperature 121 12 1 12: 2 5 ºC 6 min oils tallow 98 98% mass viscosity specifications (TGA 9

Herein, we report the synthesis and evaluation of four aminoguanidine hydrazone derivatives with different aromatic moieties. This class of compounds presents a series of biological applications. Derivative AGH-3 with an indole nucleus offered the highest antioxidant capacity with results comparable to Trolox in 2,2-diphenyl-2-picrylhydrazyl radical (DPPH•), 2,2-azinobis(3 ethylbenzothiazoline-6-sulfonic acid (ABTS•+), FeIII reduction assay (FRAP), and nitric oxide (•NO) radical scavenging assays. Furthermore, AGH-3 showed the highest antiproliferative activity against human kidney cancer cells (786-0) with concentration necessary to inhibit 50% cell growth (GI50) = 6.3 μM; additionally, in biophysical studies, AGH-3 interacted with ctDNA (biological target model) forming a fluorescent supramolecular complex with a binding constant (Kb) of 2.89 × 103 M-1 with preferentially an intercalator mechanism. The tested compounds revealed the potential of aminoguanidine hydrazones as a strategic class of compounds with multitarget biological activity. Herein moieties applications AGH3 AGH 3 AGH- 2,2diphenyl2picrylhydrazyl 22diphenyl2picrylhydrazyl diphenylpicrylhydrazyl 2,2 diphenyl 2 picrylhydrazyl DPPH•, DPPH DPPH• , (DPPH•) 2,2azinobis3 22azinobis3 azinobis 2,2-azinobis( ethylbenzothiazoline6sulfonic ethylbenzothiazolinesulfonic ethylbenzothiazoline 6 sulfonic ABTS•+, ABTS ABTS•+ (ABTS•+) FRAP, FRAP (FRAP) •NO NO (•NO assays Furthermore 7860 786 0 (786-0 50 GI50 GI (GI50 63 6. μM additionally studies model Kb (Kb 289 89 2.8 10 M1 M 1 M- mechanism 2diphenyl2picrylhydrazyl 22 2, (DPPH• 2azinobis3 2,2azinobis 22azinobis 2,2-azinobis ABTS• (ABTS•+ (FRAP 78 (786- 5 GI5 (GI5 28 8 2. (DPPH 2azinobis (ABTS• 7 (786 (GI (ABTS (78 (7 (

Urea is the most widely used nitrogen fertilizer worldwide. However, ammonia volatilization, resulting from applying urea to the soil surface, causes economic and environmental losses; thus, urease inhibitors have been developed to mitigate these losses. In this work, the anti-ureolytic activity of Schiff’s base 4-(3-hydroxybenzylideneamino) phenol (3B4) and its amine-derived (3B4a) was evaluated. The most promising urease inhibitor in soil was 3B4 (55.0 ± 3.9% inhibition), with comparable results to N-(butyl) thiophosphoric triamide (p = 0.659). In the in vitro analysis (Canavalia ensiformis), the results of anti-ureolytic activity were similar, 22.6 ± 6.9% for 3B4 and 24.2 ± 9.6% for 3B4a. Biophysical interaction studies were also carried out through molecular docking studies and molecular fluorescence spectroscopy. These studies showed that both substances are preferentially competitive inhibitors, with the interaction between 3B4a and urease forming a more stable complex. In the analysis by Fourier transform infrared spectroscopy, no interaction was observed when 3B4 or 3B4a was mixed with urea (1:1) for 48 h, providing evidence of compatibility. Thus, the Schiff base 3B4 and its corresponding amine 3B4a may represent potential additives for urea fertilization aiming to assist in the urease inhibition process. worldwide However volatilization surface losses thus work antiureolytic anti ureolytic Schiffs s 43hydroxybenzylideneamino hydroxybenzylideneamino 4 3 4-(3-hydroxybenzylideneamino B (3B4 aminederived derived Ba (3B4a evaluated 3B 55.0 550 55 0 (55. 39 9 3.9 inhibition, , inhibition) Nbutyl N butyl N-(butyl p 0.659. 0659 0.659 . 659 0.659) Canavalia ensiformis, ensiformis ensiformis) similar 226 22 6 22. 69 6.9 242 24 2 24. 96 9.6 spectroscopy complex 11 1 (1:1 h compatibility Thus process (3B 55. 5 (55 3. 065 0.65 65 6. 9. (1: (5 06 0.6 (1 ( 0.

Niobium pentoxide shows an interesting reactivity that allows the control of different aspects of its morphology and chemistry. In this study, Nb2O5 nanoparticles were modified with protoporphyrin IX (PPIX) and tris(ethynylphenyl) pyrene derivative (PyPh3) by using 3-aminopropyltriethoxysilane as linkage group and used as photosensitizers against lung cancer. The antitumor photoactivity against the A549 tumor cell line as a model of in vitro study showed half maximal inhibitory concentration (IC50) ca. 15 μmol L-1 for both materials and the absence of dark activity, indicating the viability of dye-modified Nb2O5 as a photodynamic therapy (PDT) agent. chemistry NbO Nb O Nb2O PPIX (PPIX trisethynylphenyl tris ethynylphenyl tris(ethynylphenyl PyPh3 PyPh (PyPh3 3aminopropyltriethoxysilane aminopropyltriethoxysilane 3 cancer A A54 IC50 IC (IC50 ca 1 L1 L L- activity dyemodified dye PDT (PDT agent (PyPh A5 IC5 (IC5 (IC

Hematological problems are associated with Coronavirus disease 2019 (COVID-19). Respiratory impairment is the higher point studied, although without experimental studies related to the oxygen transport performed by erythrocytes. Therefore, we decided to investigate if erythrocytes from COVID-19 patients have their functionality changed. The case-control study included hospitalized patients with a positive real-time polymerase chain reaction (RT-PCR) result admitted to University Hospital. Volunteers (negative RT-PCR results) were recruited as a control group. Thus, we assessed different erythrocytes parameters, oxidative stress markers, and biophysical studies using whole blood and isolated hemoglobin. We found a decrease of 51% in oxygen uptake and reduced antioxidant enzyme activity in COVID-19 patients compared to controls. Raman spectrometry showed structural changes in the hemoglobin and lipids of the erythrocytes from COVID-19 patients; thus, these results were consolidated with an increase in Young’s modulus in erythrocytes followed by morphology changes. Besides, isolated hemoglobin from COVID-19 patients has a distinct interaction profile using a ligand model compared to the control. COVID-19 leads to structural, functional, and morphological damage to human erythrocytes. Our data showed structural and molecular changes and induction of oxidative stress in erythrocytes by COVID-19, a new perspective on the contribution of erythrocytes to a respiratory commitment in COVID-19. 201 COVID19. COVID19 COVID 19 . (COVID-19) studied Therefore COVID-1 changed casecontrol case realtime real time RTPCR RT PCR (RT-PCR Hospital negative group Thus parameters markers 51 controls thus Youngs Young s Besides functional COVID19, 19, 19. 20 COVID1 1 (COVID-19 COVID- 5 2 (COVID-1 (COVID- (COVID

In this study, the interaction between benzothiazole (BTA, concentration of a drug required for 50% inhibition in vitro (IC50) = 0.77 mM) and benzimidazole (BIA, IC50 = 2.14 mM) with urease was quantitatively assessed, using UV-Vis, molecular fluorescence, and circular dichroism. The results showed that both compounds interact with urease by a static fluorescence quenching mechanism with a non-fluorescent complex formation. The main forces responsible for stabilizing the supramolecular complex between BTA and urease were hydrophobic while, for BIA, van der Waals interactions and hydrogen bonds were the main ones. Urease conformation changes due to the interaction process were analyzed by circular dichroism and synchronous fluorescence. Besides, a competitive assay with substrate and inhibitors was used to evaluate the preferential urease site of interaction with BTA and BIA. Our experimental and theoretical studies supported that both, BTA and BIA, are mixed-inhibitors of ureases with a slight preference to the active site of such enzymes. Finally, both BTA and BIA showed to possess anti-Helicobacter pylori (one reference strain and six clinical isolates) activity, presenting minimal inhibitory concentration (MIC) values ranging from 38-150 and 20-164 µM, respectively. The urease inhibitors omeprazole and hydroxyurea showed MIC values in the range of 46-185 µM and 1683-> 3366 µM, respectively.

Various beneficial biological activities have been reported for passion fruit (Passiflora edulis), grown in tropical and subtropical regions. However, no study has yet demonstrated its action against the Zika virus (ZIKV) infection. The present study aimed to investigate the anti-ZIKV of the ethanolic passion fruit seed extract (PFSE), from which, liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis allowed to putatively annotate the occurrence of piceatannol, astringin, scirpusin A, scirpusin B, isookanin-7-O-glucoside and naringenin-7-O-glucoside, two quadranguloside derivatives, tyrosine, and phenylalanine. PFSE is well tolerated by cell lines (Vero E6 and HTR-8/SVneo) and tissue explants from the human placenta. With 1- and 24-h treatments, PFSE consistently reduced the viral load and NS1 protein expression of the two strains of ZIKV (MR766 and PE243) in placental explants and cell lines. Thus, PFSE has a promising potential for developing anti-ZIKV treatments, protecting the placenta against infection caused by ZIKV, along with relevant antioxidant potential, represented by ferric reducing antioxidant power (FRAP) of 390.5 Trolox eq per g dry extract and half maximal inhibitory concentration (IC50) for 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) of 12.1 µg mL-1, and more than 90% protection from lipid peroxidation. Although further studies need to be conducted, PFSE treatment was safe and effective in trophoblast cells and placental explants, thus representing a promising class of all-accessible products based on the reuse of industrial by-products.

Two different gold-silica-based nanomaterials were prepared: (i) silica-supported gold nanoparticles (AuNP/SiO2); and (ii) gold-silica core-shell nanoparticles (AuNP@SiO2). Three strategies for sample treatment (S), consisting in acid treatments, were employed: (S1) HNO3; (S2) HNO3 + HCl; and (S3) HF + HNO3 + HCl, applying microwave oven digestion for S2 and S3. From three calibration curves, slope, intercept, and linear correlation coefficient were obtained. The accuracy of the methods was evaluated by comparing the gold contents in a sample determined by flame atomic absorption spectrometry (FAAS) and by inductively coupled plasma atomic emission spectrometry (ICP-OES). Finally, the amount of gold for all samples was determined by FAAS. UV-Vis spectroscopy and transmission electron microscopy (TEM) were used to compare the material before and after sample treatment. By comparison, the application of S2 and S3 allowed the presence of gold on or in the silica matrix to be determined and the amount quantified.

The Mundaú lagoon (Maceió, AL), besides being relevant socially, economically, and culturally, also in its surroundings, presents an intense anthropic occupation, characterized by a large population and the industrial activities presence. In this systematic environmental monitoring study (from 2017 to 2019), concentrations of Al, As, Bi, Cd, Cr, Cu, Fe, Hg, Li, Mn, Mo, Ni, Pb, Sb, Sn, V, and Zn in surface waters, and total Hg content in the bivalve Mytella charruana (sururu) were recorded, using cold vapor atomic fluorescence spectrometry (or hydride generation) (HG/CV AFS), inductively coupled plasma mass spectrometry (ICP-MS), and chronopotentiometry. In the water samples, the following elements presented concentrations above the values recommended by the National Council for the Environment (CONAMA), in µg L−1: Al (24.4−2008), Cu (1.88-13.03), Fe (84.9-4107), Hg (<0.0069-2.92), Mn (10.65-200), Pb (192-1443) and Zn (121-997), and therefore, the water was classified following the water pollution index (WPI), as highly impure and polluted. The Hg content in sururu, the main food in Mundaú lagoon, ranged from 0.036-0.63 mg kg−1 (dry weight). Further, the chemometric evaluation of the data based on the principal component and correlation analysis suggested a chemical-defined profile at the different sampling points.

CdTe quantum dots (QD-CdTe) functionalized with mercaptosuccinic acid (MSA) were synthesized in an aqueous medium, varying synthesis time from 0.5 to 4 h. The nanoprobe were characterized by a direct relationship between synthesis time and QD size (2.61-3.04 nm). The QD-CdTe-MSA interacted with protamine (PT), a cationic protein, forming a bioconjugate, thus quenching the photoluminescence intensity and generating an on-off system. The nanoprobe produced at a synthesis time of 1 h (QD-CdTe1) presented PT’s best sensitivity in a succinate buffer (pH = 5). Under the optimized conditions, the proposed method presented a linear range of 0.05-0.5 mg L-1 (10-100 nM), limit of detection (LOD) 0.01 mg L-1 (2 nM), and relative standard deviation (RSD) ≤ 2.01% (n = 10). The interaction of the nanoprobe and PT led to aggregation due to a bioconjugate formation. The systems’ hydrodynamic radius varied from 4.31 nm (QD-CdTe1) to 30.50 nm for the bioconjugate (QD-CdTe1-PT). The method was sensitive to variation in ionic strength and based on thermodynamic parameters; it was demonstrated that the interaction mechanism occurred preferentially through electrostatic forces. Finally, the method proved to be fast, sensitive, and viable for quantifying PT in drugs and synthetic urine samples with recoveries above 95%.

This work proposes a spectrofluorometric method for the determination of total antioxidant capacity (CAO) in beverage samples, based on inhibition of thiochrome formation (λex = 370 nm, λem = 440 nm); a product of thiamine (vitamin B1) oxidation from K3Fe(CN)6. In the development of the method, gallic acid (GA) was used as a reference, and inhibition of thiochrome formation (in percentage) was used as the analytical response. The selectivity of the method was evaluated using seven different compounds (gallic acid, ascorbic acid, quercetin, butylhydroxytoluene (BHT), 6-hydroxy-2,5,7,8-tetramethylchroman-2 (Trolox), cysteine, and glucose). As proof of concept, the proposed method was applied in the determination of CAO in different samples, such as teas and infusions, red wines, and white wines. The results were compared with the Folin-Ciocalteu (FC), 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS•+), and 2,2-diphenyl-1-picrylhydrazyl (DPPH•) methods using the linear correlation between the methods (at 95% confidence). We observed excellent agreement between the proposed method and FC (correlation coefficient (r) = 0.9768) and ABTS•+ (r = 0.9842), compared with DPPH• method (r = 0.8502). For the determination of total CAO in beverages, the proposed method developed proved to be fast, sensitive, simple, and the results were in agreement with established assays.

ABSTRACT Background: Several studies have evaluated the effect of infectious diseases and vaccine protocols during pregnancy on maternal milk immunoglobulin (Ig) levels, to understand the protection conferred by lactation on newborns. Colostrum is the primary source of maternal IgA for the newborn. IgA participates in protection mechanisms in the neonate’s mucosa. In humans, IgA has two subclasses with differential anatomical distribution among mucosal compartments. Total IgA levels in maternal milk vary after antigen stimulation and have differential affinities in function of the chemical composition of the antigens. We studied the effect of antigenic stimulation during pregnancy on the concentrations of specific IgA1 and IgA2 subclasses in human colostrum. Methods: We analyzed data from 113 women in Mexico City and compared the amount of IgA subclasses in colostrum against three antigens: two from vaccine protocols (tetanus toxoid and pneumococcal polysaccharides) and lipopolysaccharide, a ubiquitous antigen in the gastrointestinal tract. Results: In agreement with the previous reports, we showed that IgA1 from colostrum mainly recognized protein antigens; in sharp contrast, IgA2 was mostly directed against polysaccharide antigens. These levels increased in women who had previous contacts through vaccination or infections during pregnancy. Conclusions: Antigen interaction during pregnancy increased the amount of specific IgA subclasses, depending on the chemical composition of the antigen.

Assessment of phosphorus in fruit juices is of great interest due to its essentiality and nutritional properties. This study applied sample treatment strategies to determine phosphorus in fractions of juices. Firstly, total phosphorus (Ptotal) was determined from digestion and sample suspension exploring direct analysis by inductively coupled plasma optical emission spectrometry, which presented no significant difference, for 95% of confidence level. Then, free phosphorus (Pfree) was determined by spectrophotometry and represented 30-90% of Ptotal with an inverse relationship respecting Ptotal concentration. Fractioning according to particle size evidenced highest fraction of Pfree in samples after filtration. Fractioning of phosphorus based on its charge was also performed and the high percentages of P in the anionic fraction (from 91.2 to 95.9%) are related to free inorganic phosphate in equilibrium with its protonated forms. Thus, it is more assailable after consumption, giving this food great functionality on human diet.

A população de plantas e a adubação com micronutrientes influenciam diretamente o comportamento do feijão-caupi(Vigna unguiculata (L.) Walp.), e dependem das condições de plantação, das características morfológicas e fisiológicas e da capacidade produtiva das cultivares, resultando, assim, na produção de sementes de alta qualidade. Nesse sentido, o objetivo deste trabalho foi verificar os efeitos de doses de molibdénio e densidades de plantas na produção e qualidade de sementes de feijão-caupi, cultivar BRS Novaera. O delineamento experimental foi em blocos casualizados, com quatro repetições, sendo os tratamentos dispostos em esquema fatorial 4 x 4, envolvendo quatro doses de molibdénio aplicadas via semente (0, 40, 80 e 120 g.ha-1) e quatro densidades populacionais (100, 160, 220 e 280 mil plantas.ha-1). Após a colheita, determinou-se a produtividade e as sementes foram submetidas às seguintes avaliações: teor de humidade, massa de mil sementes, germinação, emergência de plântulas, índice de velocidade de emergência, comprimento e massa seca da parte aérea de plântulas. A aplicação de doses de molibdénio via sementes não afetou a produção e a qualidade das sementes da cultivar. Entretanto, o aumento da densidade de plantas por hectare promoveu acréscimos significativos na produtividade e na massa de mil sementes.

The plant population density and fertilization with micronutrients directly influence the cowpea Vigna unguiculata (L.) Walp. performance, depending on the growing conditions, the morphological and physiological characteristics, and productive capacity of the cultivars thus affecting the quality of seeds. The aim of this study is to evaluate the effects of doses of molybdenum and plant density on the yield and quality of cowpea seeds, cultivar BRS Novaera. Randomized block design with four replications was used, with the treatments being 4 x 4 factorial, involving four molybdenum rates applied to seeds (0, 40, 80 and 120 g.ha-1) and four population densities (100, 160, 220 and 280 thousand plants.ha-1). After harvesting, productivity was determined, and the seeds were submitted to the following evaluations: moisture content, mass of one thousand seeds, germination, seedling emergence, emergence speed index, length and dry mass of shoot. The application of molybdenum to seeds did not affect production and the quality of the seeds. However, the increase in plant population density led to significant increases in productivity and mass of a thousand seeds.