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61.
Juliana Mendes de Oliveira Iara Alves Anes Jorge Luís Coleti Denise Crocce Romano Espinosa Marcelo Siqueira de Carvalho Jorge Alberto Soares Tenório 《加拿大化工杂志》2023,101(4):1743-1761
Niobium (Nb) and Tantalum (Ta) are used to increase materials' mechanical resistance and produce lighter alloys. Worldwide Nb production reached 78 000 t in 2020. The reduced ore offer justifies the recycling of these metals from tin slag, contributing to the circular economy. Nb2O5 and Ta2O5 extraction either from the primary source or the tin slag is an industrial challenge. Nb and Ta dissolution processes already implemented are fluoride leaching, sulphuric leaching, alkaline leaching, and alkaline roasting. The fluoride process raises environmental concerns about waste control. The sulphuric method can be managed to have higher Nb and Ta extraction in a less aggressive process, if some changes are implemented, such as increasing the number of extraction steps, decreasing the pulp density, or increasing the temperature; however, the efficiency of this methodology must be tested for tin slag. The alkaline method seems to be more selective to Nb and Ta by reactants and temperature control. Despite those well-established Nb and Ta treatments, they must be adapted to recover Nb and Ta from slag. The slag has low Nb and Ta content, while high Si and Ca concentrations exist in the matrix. This paper brings the main methods used to extract the Nb and Ta from the primary resources and an overview of Nb and Ta recovery from the slag. This investigation comes as a tool to guide the development of new methods to recover Nb and Ta from low-grade sources such as tin slag. 相似文献
62.
Male-specific compounds, previously identified from Phyllotreta cruciferae and synthesized or isolated from natural sources, attracted both sexes of the beetle in field trials and therefore function as components of a male-produced aggregation pheromone. Six field experiments of 7 to 10 d duration each were conducted over 2 yr using modified boll weevil traps and two doses of pheromone. Treatments containing two doses of allyl isothiocyanate (AITC), a breakdown product of glucosinolates in Brassica napus L., a host plant of the beetles, were included in the study. A dose response was observed for both the pheromone components and AITC, and combinations of the pheromone and AITC generally attracted greater numbers of flea beetles than did either component itself. This increased attraction to a combination of beetle-produced compounds and host odors has not been previously demonstrated in halticine beetles and could help explain patterns of movement by P. cruciferae into field crops. 相似文献
63.
Yordanka Gluhcheva Irena Pashkunova-Martic Martin Schaier Ivelin Vladov Silviya Stoykova Emilia Petrova Ekaterina Pavlova Peter Dorkov Thomas H. Helbich Bernhard Keppler Juliana Ivanova 《International journal of molecular sciences》2022,23(8)
Lead (Pb) exposure induces severe nephrotoxic effects in humans and animals. Herein, we compare the effects of two chelating agents, salinomycin and deferiprone, on Pb-induced renal alterations in mice and in the homeostasis of essential elements. Adult male mice (Institute of Cancer Research (ICR)) were randomized into four groups: control (Ctrl)—untreated mice administered distilled water for 28 days; Pb-exposed group (Pb)—mice administered orally an average daily dose of 80 mg/kg body weight (BW) lead (II) nitrate (Pb(NO3)2) during the first two weeks of the experimental protocol followed by the administration of distilled water for another two weeks; salinomycin-treated (Pb + Sal) group—Pb-exposed mice, administered an average daily dose of 16 mg/kg BW salinomycin for two weeks; deferiprone-treated (Pb + Def) group—Pb-exposed mice, administered an average daily dose of 20 mg/kg BW deferiprone for 14 days. The exposure of mice to Pb induced significant accumulation of the toxic metal in the kidneys and elicited inflammation with leukocyte infiltrations near the glomerulus. Biochemical analysis of the sera revealed that Pb significantly altered the renal function markers. Pb-induced renal toxicity was accompanied by a significant decrease in the endogenous renal concentrations of phosphorous (P), calcium (Ca), copper (Cu) and selenium (Se). In contrast to deferiprone, salinomycin significantly improved renal morphology in Pb-treated mice and decreased the Pb content by 13.62% compared to the Pb-exposed group. There was also a mild decrease in the renal endogenous concentration of magnesium (Mg) and elevation of the renal concentration of iron (Fe) in the salinomycin-treated group compared to controls. Overall, the results demonstrated that salinomycin is a more effective chelating agent for the treatment of Pb-induced alterations in renal morphology compared to deferiprone. 相似文献
64.
Ledesma Brenda C. Jurez Juliana M. Domine Marcelo E. Beltramone Andrea R. 《Catalysis Letters》2022,152(5):1530-1544
Catalysis Letters - Monometallic and bimetallic supported catalysts were developed to produce 2,5-dimethylfuran (DMF) trough hydrogenolysis of 5-(hydroxymethyl)furfural (HMF). Detailed... 相似文献
65.
Juliana M. PradoGlaucia H.C. Prado M. Angela A. Meireles 《The Journal of Supercritical Fluids》2011,56(3):231-237
Many scale-up criteria for supercritical fluid extraction (SFE) can be found in literature. However, the studies are often divergent and inconclusive; therefore, more studies on this field are needed. The objective of the present work was to study the scale-up of SFE process focusing application to Brazilian raw materials. A laboratory scale equipment (290 mL extraction vessel) and a pilot scale equipment (5.15 L extraction vessel) were used to study scale-up of SFE for clove and sugarcane residue. The scale-up criterion adopted consisted in maintaining solvent mass to feed mass ratio constant. The criterion was successfully used for a 15-fold scale-up of overall extraction curves for both raw materials studied; yields in pilot scale were slightly higher than in laboratory scale. The criterion studied allows a rapid and simple scale-up procedure, which can be very useful for the purpose of developing SFE technology at industrial scale in developing countries where such technology is still not available at industrial level. 相似文献
66.
Qaisar Nawaz Araceli de Pablos-Martín Juliana Martins de Souza e Silva Katrin Hurle Altair T. Contreras Jaimes Delia S. Brauer Aldo R. Boccaccini 《Journal of the American Ceramic Society》2020,103(8):4234-4247
In this work the influence of thermal treatment conditions on crystallization of a sol-gel-derived 45S5 bioactive glass was evaluated using DSC, XRD, TEM, EDX, and X-ray nanocomputed tomography (nano-CT). Temperature and time of the thermal treatment strongly influence the composition of the crystalline phases. At the onset of the glass transition temperature (600°C), combeite crystallizes as the main phase along with a calcium silicate-phosphate phase, which decomposes into rhenanite from 2 hours of thermal treatment at this temperature. At the crystallization temperature (700°C), combeite remains as the main crystalline phase. Additionally, Na2Ca2Si2O7 crystalline phase is formed. Our results provide a basic platform for tailoring the crystalline phases by controlling the nucleation and growth of crystalline phases via thermal treatments. Different morphologies (round particles, stacked layers, toothpick-like, and long features) were discerned by TEM as a function of temperature and time of treatment. It is the first time that bioactive glass is investigated by nano-CT at laboratory scale. This novel technique enables the 3D visualization of features in the nanometer range, giving clear information about the volumetric distribution of phases in the sample. 相似文献
67.
Dr. André L. C. S. Nascimento Richard P. Fernandes Christian Quijia Victor H. S. Araujo Juliana Pereira Prof. Dr. Jerusa S. Garcia Prof. Dr. Marcello G. Trevisan Prof. Dr. Marlus Chorilli 《ChemMedChem》2020,15(12):1018-1029
Since the beginning of the HIV epidemic, research has been carried out to control the virus. Understanding the mechanisms of replication has given access to the various classes of drugs that over time have transformed AIDS into a manageable chronic disease. The class of protease inhibitors (PIs) gained notice in anti-retroviral therapy, once it was found that peptidomimetic molecules act by blocking the active catalytic center of the aspartic protease, which is directly related to HIV maturation. However, mutations in enzymatic internal residues are the biggest issue for these drugs, because a small change in biochemical interaction can generate resistance. Low plasma concentrations of PIs favor viral natural selection; high concentrations can inhibit even partially resistant enzymes. Food-drug/drug-drug interactions can decrease the bioavailability of PIs and are related to many side effects. Therefore, this review summarizes the pharmacokinetic properties of current PIs, the changes when pharmacological boosters are used and also lists the major mutations to help understanding of how long the continuous treatment can ensure a low viral load in patients. 相似文献
68.
Carlos Eduardo de Ara jo Padilha Juliana Chris Silva de Azevedo Francisco Canind de Sousa J nior S rgio Dantas de Oliveira J nior Domingos Fabiano de Santana Souza Jackson Ara jo de Oliveira Gorete Ribeiro de Macedo Everaldo Silvino dos Santos 《中国化学工程学报》2018,26(12):2471-2476
In this study the potential of cloud point extraction formed by a non-ionic surfactant was used in order to separate polyphenols from industrial residues of camu-camu. The effects of operational conditions of the cloud point extraction (CPE) on the polyphenol recovery and volumetric ratio were investigated. The results showed a maximum recovery of 95.71% that was obtained using 7.0 wt% Triton X-114, native pH (3.25), and 80 wt% polyphenol extract at 30 °C. The use of cloud point extraction was successful to recover the polyphenols from agroindustrial residue since it is a simple as well as of low-cost technique. 相似文献
69.
Tasnuva Sarwar Tunna Kashif Ghafoor Sahena Ferdosh Juliana Md Jaffri Fahad Y Al-Juhaimi 《分离科学与技术》2018,53(2):243-260
Supercritical fluid extraction (SFE) using carbon dioxide (CO2) and liquid CO2 using Soxhlet (CO2-Soxhlet) extraction were employed to extract three (3) antidiabetic compounds viz. stigmasterol, quercetin, and avicularin from Mimosa pudica. Various extraction parameters were studied. Extracts were analyzed pharmacologically, qualitatively and quantitatively to ascertain enrichment levels. All three antidiabetic compounds were effectively enriched under optimized conditions of temperature 60°C, pressure 40 MPa, co-solvent ratio 30%, and CO2 flow rate of 5 ml min?1. SFE was found to be the better method for enrichment of the antidiabetic compounds than the CO2-Soxhlet method. Extraction conditions were seen to affect the enrichment of desired compounds. 相似文献
70.
Juliana Coatrini SoaresAndré Brisolari Valquíria da Cruz RodriguesEdgar Aparecido Sanches Débora Gonçalves 《Reactive and Functional Polymers》2012,72(2):148-152
Urease (Urs) was immobilized in electrochemically prepared polypyrrole (PPy) and the resulting films were characterized by cyclic voltammetry, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and ultraviolet visible spectroscopy (UV-VIS). The enzymatic activity of Urs entrapped in the PPy matrix was confirmed by the catalytic conversion of urea into carbon dioxide and ammonia, when urea was detected amperometrically at different concentrations in standard samples and commercial fertilizers. The PPy/Urs biosensors exhibited selectivity, a relatively high efficiency at urea concentrations below 3.0 mmol L−1, and a sensitivity to urea of 2.41 μA cm−2 mmol−1 L. 相似文献