A mechanistic study on conversion of carbon dioxide into formic acid promoted by 1-ethyl-2, 3-dimethyl-imidazolium nitrite.

CONTEXT: The conversion of carbon dioxide (CO2) to formic acid (FA) through hydrogenation using 1-ethyl-2,3- dimethyl imidazolium nitrite (EDIN) ionic liquid was studied to understand the catalytic roles within EDIN. CO2 hydrogenation in various solvents has been explored, but achieving high efficiency and selectivity remains challenging due to the thermodynamic stability and kinetic inertness of CO2. This study explored two mechanistic pathways through theoretical calculations, revealing that the nitrite (NO2-) group is the most active site. The oxygen site on nitrite favorably activates H2, while the nitrogen site shows a minor activation barrier of 108.90 kJ/mol. The Gibbs energy variation indicates stable FA formation via EDIN, suggesting effective hydrogen (H2) activation and subsequent CO2 conversion. These insights are crucial for developing improved catalytic sites and processes in ionic liquid catalysts for CO2 hydrogenation. METHODS: Quantum chemical calculations were conducted using the ORCA software package at the Restricted Hartree-Fock (RHF) and density functional theory (DFT) levels. The RHF method, known for its predictive abilities in simpler systems, provided a baseline description of electronic structures. In contrast, DFT was employed for its effectiveness in complex interactions involving significant electron correlation. A valence triple-zeta polarization (def2-TZVPP) basis set was employed for both RHF and DFT, ensuring accurate and correlated calculations. The B3LYP functional was utilized for its rapid convergence and cost-efficiency in larger molecules. Dispersion corrected functionals (DFT-D) addressed significant dispersion forces in ionic liquids, incorporating Grimme's D2, D3, and D4 corrections. Geometry optimizations, kinetics, and thermodynamic calculations were performed in the gas phase. The Nudged Elastic Band Transition State (NEB-TS) approach, combining Climbing Image-NEB (CINEB) and Eigenvector-Following (EF) methods, was used to find the minimum energy path (MEP) between reactants and products. Thermochemical analyses based on vibrational frequency calculations evaluated properties such as Enthalpy, Entropy, and Gibbs energy using ideal gas statistical mechanics.

Primeiro registro de machos de Amblyomma rotundatum (Acari: Ixodidae) em jabuti-tinga (Chelonoidis denticulatus) no estado do Amazonas, Amazônia brasileira: relato de caso / First record of males of Amblyomma rotundatum (Acari: ixodidae) on yellow-footed tortoise (Chelonoidis denticulatus) in the Amazonas state, Brazilian Amazon: case report

O carrapato Amblyomma rotundatum é uma espécie partenogenética, encontrada principalmente em anfíbios e répteis silvestres em todos os biomas brasileiros. No presente relato, registra-se a ocorrência de dois machos dessa espécie de ixodídeo encontrados em um jabuti-tinga (Chelonoidis denticulatus) proveniente do município de Manaus, Amazonas, Brasil.(AU)

The Amblyomma rotundatum tick is a parthenogenetic species, found mainly in wild amphibians and reptiles in all Brazilian biomes. The present report records the occurrence of two males of this ixodid species found on yellow-footed tortoise (Chelonoidis denticulatus) from the municipality of Manaus, Amazonas, Brazil.(AU)

Desempenho produtivo e econômica de surubins (pseudoplatystoma sp) alimentados com níveis de proteína e estocados em tanque-rede / Growth performance and economic of pseudoplatystoma sp fed with protein levels reared in net cages

O surubim (Pseudoplatystoma sp.) é uma das espécie de peixe mais apreciadas para o consumo. Por ser uma espécie carnívora, exige atenção especial no que tange às suas exigências nutricionais. Até o momento, poucos estudos foram realizados para estabelecê-las na fase de engorda, em especial em sistema de cultivo intensivo. O objetivo do presente estudo foi avaliar os desempenhos zootécnico e econômico de surubins (Pseudoplatystoma sp.) na fase final de crescimento, estocados em tanque-rede e alimentados com dietas com diferentes níveis de proteína. Os peixes, com peso de 356,6±40,3g, foram acondicionados em 12 tanques-rede de 18m3, nos quais permaneceram por cinco meses até adquirirem o peso comercial para abate. O tratamento experimental foi constituído por três dietas extrusadas comerciais, com os níveis de proteína bruta (36, 38, 40%PB) sendo substituídos gradativamente por carboidratos. Foram avaliados os parâmetros de crescimento, rendimento de filé, enzimas metabólicas e desempenho econômico. O ganho de peso, o ganho de peso diário, o consumo de dieta, a taxa de eficiência proteica, a sobrevivência e o rendimento de filé não apresentaram diferença significativa. A conversão alimentar foi melhor para os peixes alimentados com a dieta com 38 e 40%PB. Não foram observadas diferenças significativas para os parâmetros de índice hepatossomático e de enzimas hepáticas. Apesar dos maiores gastos com a ração contendo 38%PB em comparação à dieta com 36%PB, esta foi a que apresentou o melhor índice de custo por kg de peixe produzido. Os melhores índices de crescimento e o menor custo de arraçoamento foram obtidos pelos peixes alimentados com a dieta 38%PB, sendo esta, portanto recomendada para o arraçoamento na fase final de surubins em tanque-rede.

The Pseudoplatystoma sp. is one of the most appreciated fish species for consumption. Being a carnivorous species, the painted requires special attention regarding their nutritional requirements. To date, few studies have been conducted to establish them in their stage of fattening especially in intensive cultivation systems. The aim of the present study was to evaluate the growth and economic performance of Pseudoplatystoma sp fed with protein levels reared in net cages. The fish weighing from 356.6 ± 40.3g were packed in twelve net cages in 18 m3 in which they remained for five months until acquiring the commercial weight for slaughter. The experimental treatment was constituted by three commercial extruded diets with different crude protein levels (36, 38, 40% CP) gradually being replaced with carbohydrate. Growth parameters, metabolic enzymes, fillet yield and economic performance were evaluated. The gain in weight, daily weight gain, diet consumption, protein efficiency rate, survival and fillet yield did not show significant difference. The feed conversion was best for fish fed a diet with 38 and 40% CP. No significant differences were observed for the hepatossomatic index parameters and liver enzymes. There were larger expenditures on rations containing 38% PB compared to the diet with 36% CP, this presented the best index of cost per kg of fish produced. The best growth rates and lower cost of feeding were obtained by fish fed with a 38% CP diet, which is, therefore, recommended for feeding in the final phase of surubins monitored via net cages.

Comparative study of different matrix/solvent systems for the analysis of crude lyophilized microalgal preparations using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

RATIONALE: Due to increases in greenhouse gas emissions, it is necessary to explore renewable sources of energy. Interesting alternatives are biofuels derived from microalgae. One challenge is the development of a detailed microalgae database compiling species identifications and characterizations that would facilitate microalgae selection for biomass production. Mass spectrometric (MS) analysis using a matrix-assisted laser desorption/ionization (MALDI) source is an advanced technique that enables advancement in this biological area. In this work a MALDI time-of-flight (TOF)MS method for the rapid identification of proteins in whole cells of selected microalgae species was studied. Furthermore, the efficiency of different matrix and solvent systems was tested. MS analyses were performed using an UltrafleXtreme MALDI-TOF mass spectrometer operating in linear positive ion mode. METHODS: Mass spectra were acquired in a mass range from 4000 to 20,000 Da with ions generated from Smartbeam laser irradiation using a frequency of 2000 Hz, a PIE 100 ns and a lens 7 kV. The voltage was 25 kV for the first ion source and 23 kV for the second. Each spectrum was generated by averaging of 10,000 laser shots and the laser irradiance was set at 95-100%. RESULTS: Similar mass spectra were obtained for all matrices (SA, HCCA, DHB and sDHB); however, the use of the sDHB matrix resulted in spectrum profiles with a greater amount number of proteins, a better signal/noise (S/N) ratio and higher intensities for the majority of microalgae analyzed. Trifluoroacetic acid (TFA) content was also studied and the best results in terms of S/N ratio, number of proteins and signal intensities were obtained with 0.1% TFA in the matrix solvent. The addition of isopropanol did not produce improvement in the quality of spectrum profiles. CONCLUSIONS: Therefore, the optimal matrix for the analysis of protein from intact microalgae cells is sDHB with TA50 as the matrix solvent and without isopropanol. These conditions allow the acquisition of high quality spectrum profiles.

Monitoring of metals, organic compounds and coliforms in water catchment points from the Sinos River basin.

Unplanned use and occupation of the land without respecting its capacity of assimilation and environmental purification leads to the degradation of the environment and of water used for human consumption. Agricultural areas, industrial plants and urban centres developed without planning and the control of effluent discharges are the main causes of water pollution in river basins that receive all the liquid effluents produced in those places. Over the last decades, environmental management has become part of governmental agendas in search of solutions for the preservation of water quality and the restoration of already degraded resources. This study evaluated the conditions of the main watercourse of the Sinos River basin by monitoring the main physical, chemical and microbiological parameters described in the CONAMA Resolution no. 357/2005.The set of parameters evaluated at five catchment points of water human consumption revealed a river that has different characteristics in each reach, as the upper reach was class 1, whereas the middle and lower reaches of the basin were class 4. Monitoring pointed to households as the main sources of pollutants in those reaches, although metals used in the industrial production of the region were found in the samples analyzed.

Evaluation of genotoxicity and cytotoxicity of water samples from the Sinos River Basin, southern Brazil.

Some water bodies in the Sinos River Basin (SRB) have been suffering the effects of pollution by residential, industrial and agroindustrial wastewater. The presence of cytotoxic and genotoxic compounds could compromise the water quality and the balance of these ecosystems. In this context, the research aimed to evaluate the genotoxicity and cytotoxicity of the water at four sites along the SRB (in the cities of Santo Antônio da Patrulha, Parobé, Campo Bom and Esteio), using bioassays in fish and cell culture. Samples of surface water were collected and evaluated in vitro using the Astyanax jacuhiensis fish species (micronucleus test and comet assay) and the Vero lineage of cells (comet assay and cytotoxicity tests, neutral red - NR and tetrazolium MTT). The micronucleus test in fish showed no significant differences between the sampling sites, and neither did the comet assay and the MTT and NR tests in Vero cells. The comet assay showed an increase in genetic damage in the fish exposed to water samples collected in the middle and lower sections of the basin (Parobé, Campo Bom and Esteio) when compared to the upper section of the basin (Santo Antônio da Patrulha). The results indicate contamination by genotoxic substances starting in the middle section of the SRB.

Cytotoxicity assays as tools to assess water quality in the Sinos River basin.

Cytotoxicity assays using cell cultures may be an alternative to assess biological toxicity of surface waters and may help to improve the control of water quality. This study compared two methods to prepare culture media for the exposure of Hep-2 cells to water samples collected from the Rolante River, an important affluent of the Sinos River. The toxicity was evaluated using the MTT and neutral red assays. Two methods were used to prepare culture media. In method 1, the sample was diluted at 1:1, 1:10, 1:100, 1:1000, 1:10.000 (v/v, sample/medium) in a standard culture medium; in method 2, water samples were used as the solvent for the culture medium, which was prepared at concentrations of 100, 80, 60, 40 and 20%. Semi-confluent cultures were then exposed to the media test for 24 hours, and cytotoxicity was determined immediately using the MTT and NR assays. Mitochondrial activity (MTT) was significantly lower at all concentrations in both methods, except at 1:1000 in method 1. However, the lysosome viability (NR) results revealed cytotoxicity only in the 1:1 sample of method 1. Both culture preparation methods were efficient and sensitive to the MTT assay, but method 2 seemed to be more adequate for the NR assay. The Rolante River has cytotoxic contaminants to Hep-2 cells, which may be one of the explanations for the poor water quality of the Sinos River basin.

Caffeine as an indicator of human fecal contamination in the Sinos River: a preliminary study.

The preservation of hydric resources is directly related to fecal contamination monitoring, in order to allow the development of strategies for the management of polluting sources. In the present study, twenty-five water samples from six water public supply collection sites were used for the evaluation of the presence of caffeine, total and fecal coliforms. Caffeine was detected in all samples, with concentrations ranging from 0.15 ng mL-1 to 16.72 ng mL-1. Total coliforms were detected in all samples, with concentrations in the range of 52 NMP/100 mL to higher than 24196 NMP/100 mL, whether the concentration range for fecal coliforms was in the range of below 1 NMP/100 mL to 7800 NMP/100 mL. No significant correlation was found between total coliforms and caffeine concentrations (rs = 0.35, p = 0.09). However, a moderate correlation between fecal coliforms and caffeine concentrations was found (rs = 0.412, p <0.05), probably indicating a human source for these bacteria. Caffeine determination in water may be a useful strategy to evaluate water contamination by human fecal waste.

Corporate governance and proactive environmental management in Novo Hamburgo and neighbouring cities, Brazil.

This study compiled data on environmental auditing and voluntary certification of environment-friendly businesses of the Commercial and Industrial Association of Novo Hamburgo, Campo Bom and Estância Velha and analysed them according to classical environmental management principles: sustainable development and corporate governance. It assessed the level of application of the concepts of corporate governance to everyday business in companies and organisations and estimated how the interconnection and vertical permeability of these concepts might help to make bureaucratic environmental management systemic, proactive and evaluative, changes that may add great value to the operations evaluated. Results showed that, when analysing only audited items not directly defined in legislation, no significant changes were identified. The inclusion of more advanced indices may promote the transition from bureaucratic management, which meets regulated environmental standards only satisfactorily, into proactive and systemic environmental management, which adds value to companies and helps to perpetuate them. Audited and analysed data did not reveal actions that depend on the internal redistribution of power and the interconnection or verticality of attitudes that may materialize concepts of corporate governance.

Antibiofilm activity of irrigating solutions associated with cetrimide. Confocal laser scanning microscopy.

AIM: To evaluate the antibiofilm activity of sodium hypochlorite (NaOCl) and chlorhexidine (CHX) solutions associated with cetrimide (CTR), and QMiX using confocal laser scanning microscopy. METHODOLOGY: Enterococcus faecalis (ATCC- 29212) biofilms were induced on bovine dentine blocks for 14 days. The dentine blocks containing biofilm were immersed for 1 min in the following solutions: 2.5% NaOCl; 2.5% NaOCl + 0.2% CTR; 2% CHX; 2% CHX + 0.2% CTR; 0.2% CTR; QMiX. After contact with the solutions, the dentine blocks were stained with Live/Dead(®) BacLight for analysis of the remaining biofilm using confocal laser scanning microscope. Images were evaluated using the BioImage_L software to determine the total biovolume (µm(3) ), the green biovolume (live cells) (µm(3) ) and the percentage of substrate coverage (%). The data were subjected to nonparametric statistical test using Kruskal-Wallis and Dunn's tests at 5% significance level. RESULTS: After exposure to irrigants, the total biovolume observed for CHX, CHX+CTR, CTR, QMiX was similar to distilled water (P > 0.05). NaOCl and NaOCl+CTR had the lowest total and green biovolume. The CTR and QMiX had intermediate green biovolume, with greater antibacterial activity than CHX and CHX+CTR (P < 0.05). The NaOCl and NaOCl+CTR solutions were associated with microorganism removal and substrate cleaning ability. CONCLUSIONS: NaOCl and NaOCl+CTR solutions were effective on microorganism viability and were able to eliminate biofilm. The addition of cetrimide did not influence antibacterial activity.

Within-laboratory validation of a multiresidue method for the analysis of 98 pesticides in mango by liquid chromatography-tandem mass spectrometry.

A within-laboratory validation procedure for a selective and sensitive method for the simultaneous determination of 98 pesticide residues in mango is presented. QuEChERS extraction was adapted to laboratory conditions. Mango samples (10 g) mixed with sodium sulfate (4 g) and sodium acetate (1 g) were extracted with acetonitrile/acetic acid (99/1 v/v), cleaned using dispersive solids, and subsequently identified and quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Pesticides were separated on a reversed-phase column using a gradient elution in conjunction with positive-mode electrospray ionisation. The analytical performance of the method was demonstrated by analysis of spiked mango samples at three concentration levels (0.01, 0.05 and 0.1 mg kg(-1)) for 3 different days, and the analysis was performed by three analysts. Calibration curves were statistically acceptable by the ordinary last-square method (OLSM), with a regression coefficient above 0.98 for all analytes. The method accuracy (n = 18) was between 80% and 110%, and precisions were below 20% for 95% of the analytes. The method uncertainty at the LOQ was evaluated considering the uncertainty associated with the calibration curve and the uncertainty associated with the method precision. The validation data for all pesticides were in accordance with Brazilian and European guidelines for pesticide residue analysis.

Evaluation of the thermoplasticity of gutta-percha and Resilon® using the Obtura II System at different temperature settings.

AIM: To analyse the thermoplasticity of several endodontic filling materials using the Obtura II System at different temperature settings. METHODOLOGY: The following materials based on gutta-percha: Regular Obtura (OBT), Obtura Flow 150 (OBT F), Endo Flow (EDF), Odous (ODO) and the synthetic thermoplastic polymer material Resilon (RE) were heated using the Obtura II System at three temperature settings (140, 170 and 200 °C). Samples of the heated materials were placed on the sensor of a digital thermometer (THR-140; Instrutherm, São Paulo, Brazil) to determine their real temperature (RT) when the system was set at 140 °C (from 64.5 to 69 °C), 170 °C (from 73.8 to 77.5 °C) and 200 °C (from 83.6 °C for EDF and 100 °C for RE). Specimens (n = 30) were made by placing samples of each material in metallic ring moulds and compressing them between two glass slabs. After 24 h, specimens (n = 10) were heated at the different settings (RT) and submitted to compression under a 5-kg load. Plasticization was assessed by calculating the differences between the post-compression and initial diameters of each specimen. Data were submitted to anova and Tukey's test at 5% significance. RESULTS: At 140 °C, Obtura Flow presented the highest thermoplasticity values and Regular Obtura, the lowest. At 170 °C, Obtura Flow and Resilon demonstrated greater plasticization. Resilon had the highest mean thermoplasticity values at 200 °C. CONCLUSIONS: Thermoplasticity values were influenced both by the temperature settings on the Obtura II System and by the type of material analysed. Obtura Flow and Resilon had the highest mean thermoplasticity values.

Optimal experimental design and artificial neural networks applied to the photochemically enhanced Fenton reaction.

Among advanced oxidation processes (AOPs), the photochemically enhanced Fenton reaction may be considered as one of the most efficient for the degradation of contaminants in industrial wastewater. This process involves a series of complex reactions. Therefore, an empirical model based on artificial neural networks has been developed for fitting the experimental data obtained in a laboratory batch reactor for the degradation of 2,4-dimethyl aniline (2,4-xylidine), chosen as a model pollutant. The model describes the evolution of the pollutant concentration during irradiation time as a function of the process conditions. It has been used for simulating the behavior of the reaction system in sensitivity studies aimed at optimizing the amounts of reactants employed in the process, an iron(III) salt and hydrogen peroxide, as well as the temperature. The results show that the process is most sensitive to the concentration of iron(III) salt and temperature, whereas the concentration of hydrogen peroxide has a minor effect.

Effect of 17beta-estradiol in hypercholesterolemic rabbits with severe endothelial dysfunction.

17beta-Estradiol prevents early vascular lesion development and may also affect advanced atherosclerosis. To test the antiatherosclerotic effect of estrogen under conditions that resemble more advanced human atherosclerosis with severe endothelial dysfunction, we have investigated the effect of 17beta-estradiol in hypercholesterolemic rabbits treated with the nitric oxide synthase inhibitor Nomega-nitro-L-arginine methyl ester (L-NAME). Chronic L-NAME administration attenuated endothelial nitric oxide (EDNO)-mediated vascular responses leading to significantly accelerated atherosclerotic plaque development. 17beta-Estradiol treatment alone inhibited aortic lesion formation with concurrent increase in EDNO-mediated responses. The beneficial effect of estrogen persisted in the L-NAME-treated rabbits, suggesting that the antiatherogenic action of 17beta-estradiol involves NO-independent mechanisms as well. Serum cholesterol levels were not altered by any of the treatments. 17beta-Estradiol treatment significantly increased EDNO production under these conditions as well. The reduction in plaque size by 17beta-estradiol was always accompanied by increased EDNO production, suggesting a strong association between these two events. The results demonstrate that estrogen treatment may exert protection against atherosclerosis even in patients with severe endothelial dysfunction.

Study of atmospheric ozone formation by means of a neural network-based model.

The occurrence of high ozone levels in the atmosphere of urban areas has become a serious pollution problem in a number of large cities in the world. Although mathematical models have been proposed for predicting ozone concentrations as a function of a number of gas components, sometimes there are uncertainties due to lack of the combined effects of meteorological factors and the complex chemical reaction system involved. The application of neural network models, based on measured values of air pollutants and meteorological factors at different locations within the São Paulo Metropolitan Area, combine chemical and meteorological information. This has shown to be a promising tool for predicting ozone concentration. Simulations carried out with the model indicate the sensitivity of ozone in relation to different air pollution and weather conditions. Predictions using this model have shown good agreement with measured values of ozone concentrations.

Nitric oxide release from normal and dysfunctional endothelium.

The endothelium plays a critical role in maintaining vascular tone by releasing vasoconstrictor and vasodilator substances. Endothelium - derived nitric oxide (NO) is a vasodilator rapidly inactivated by superoxide (O2-) found in significant quantities. The porphyrinic sensor (0.5-8 microm diameter) and chemiluminescence methods were used to measure NO and (O2-) respectively. Effects of hypertension, low density lipoprotein (LDL), and heart preservation on the release of NO and O2- were delineated. In the single endothelial cell (rat aorta) NO concentration was the highest in the cell membrane decreasing exponentially with distance from cell, and becoming undetectable beyond 50 microm and 25 microm for normotensive (WKY) and hypertensive (SHR) rats respectively. The endothelium of SHR released 40% less NO (300+/-25 nmol L(-1)) than that of normotensive rats (500+20 nmol L(-1)), due to the higher production of O2- in SHR rats. An exponentially decreasing NO production (from 1.20 +/- 0.15 to 0.16 +/- 0.05 micromol (L-1)) and concomitant increase of O2- generation (from 10 +/- 0.3 to 300 +/- 25 nmol L(-1) were observed in left ventricle of stored (eight hours) rabbit heart. Native and oxidized low density lipoproteins (nLDL and oxLDL) inhibited NO generation and increased O2- production. The local depletion of the L-arginine substrate may disarrange the nitric oxide synthase, leading to production of O2- from oxygen.

[Multiple fistulae in coronary artery of left ventricle]. / Múltiplas fístulas das artérias coronárias ao ventrículo esquerdo.

A 51 year-old man was admitted to the coronary care unit due an episode of retroestenal pain with ischaemic alterations in electrocardiogram. It was made the diagnosis of unstable angina. Cinecoronariography showed dilated coronary arteries without obstructions and multiples coronary fistulas draining into left ventricular cavity. Transesophagic echocardiogram with microbubbles injection into coronary arteries showed an important coronary steal phenomena. It is discussed the diagnosis and the treatment. This is one of the rare cases of coronary fistulas draining into the left ventricular cavity and the first one with alterations in the rest ECG.