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1
Venegas-García, Deysi J., et Lee D. Wilson. « Kinetics and Thermodynamics of Adsorption for Aromatic Hydrocarbon Model Systems via a Coagulation Process with a Ferric Sulfate–Lime Softening System ». Materials 16, no 2 (10 janvier 2023) : 655. http://dx.doi.org/10.3390/ma16020655.
Texte intégralRésumé :
The adsorption mechanisms for model hydrocarbons, 4-nitrophenol (PNP), and naphthalene were studied in a coagulation-based process using a ferric sulfate–lime softening system. Kinetic and thermodynamic adsorption parameters for this system were obtained under variable ionic strength and temperature. An in situ method was used to investigate kinetic adsorption profiles for PNP and naphthalene, where a pseudo-first order kinetic model adequately described the process. Thermodynamic parameters for the coagulation of PNP and naphthalene reveal an endothermic and spontaneous process. River water was compared against lab water samples at optimized conditions, where the results reveal that ions in the river water decrease the removal efficiency (RE; %) for PNP (RE = 28 to 20.3%) and naphthalene (RE = 89.0 to 80.2%). An aluminum sulfate (alum) coagulant was compared against the ferric system. The removal of PNP with alum decreased from RE = 20.5% in lab water and to RE = 16.8% in river water. Naphthalene removal decreased from RE = 89.0% with ferric sulfate to RE = 83.2% with alum in lab water and from RE = 80.2% for the ferric system to RE = 75.1% for alum in river water. Optical microscopy and dynamic light scattering of isolated flocs corroborated the role of ions in river water, according to variable RE and floc size distribution.
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Arrieta, Alberto Albis, Ever Ortiz Muñoz, Ismael Piñeres Ariza, Juan Osorio Cardozo et Jennifer Monsalvo Morales. « Catalytic effect of ferric sulfate and zinc sulfate on lignin pyrolysis ». Applied Chemical Engineering 5, no 1 (26 avril 2022) : 59. http://dx.doi.org/10.24294/ace.v5i1.1449.
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The effect of zinc sulfate and ferric sulfate on the pyrolysis process of lignin was studied at three different heating rates by using the thermogravimetric analysis technique. It was found that the pyrolysis of pure lignin is barely affected with the change of heating rates between 10 to 100 °C/min, which is unexpected because of the kinetic nature of pyrolysis. The pyrolysis kinetics of this major component of biomass was studied by using three fitting methods: the differential method with reaction order model n, the isoconversional method, and the distribution of activation energies model, DAEM. The best fit, which allowed calculating acceptable kinetic parameters, was obtained using the last method. The results show the influence of the catalysts and the heating rate on the lignin pyrolysis processes in the presence of the sulfates under study, which is confirmed by obtaining different kinetic parameters. The results suggest that zinc sulfate and ferric sulfate change the kinetic mechanism of lignin pyrolysis.
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Nagano, Tetsushi, Hiroshi Isobe, Satoru Nakashima et Midori Ashizaki. « Characterization of Iron Hydroxides in a Weathered Rock Surface by Visible Microspectroscopy ». Applied Spectroscopy 56, no 5 (mai 2002) : 651–57. http://dx.doi.org/10.1366/0003702021955222.
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In order to nondestructively characterize chemical forms of ferric hydroxides in weathered rock, charge-coupled device type visible microspectroscopy was applied to brown stains produced in weathered granite surfaces. The combination of visible microspectra and color parameters ( a* and b*) was effective in examining chemical forms of ferric hydroxides in the analytical area. Color parameters in an a*– b* diagram of the brown stains, mostly lying between goethite and ferrihydrite trends, indicated that the brown stains contain ferrihydrite or hematite in addition to goethite. Similarity of the visible microspectra of the brown stains and their first derivatives to those of goethite or ferrihydrite suggests that goethite and/or ferrihydrite are the main weathering products of the granite. Occurrence of ferrihydrite as well as goethite in the brown stains implies that crystallization of ferrihydrite to goethite might be hindered during the granite weathering. This fact suggests the possibility of toxic metal retention in ferrihydrite by its long-term persistence during water–rock interactions at the earth's surface.
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Zhu, Weixiao, Jianduo Wang, Yili Wang et Hongjie Wang. « Study on sulfadimethoxine removal from aqueous solutions by hydrous ferric oxides ». Water Science and Technology 74, no 5 (21 juin 2016) : 1136–42. http://dx.doi.org/10.2166/wst.2016.246.
Texte intégralRésumé :
Significant concerns have been raised over the presence of antibiotics including sulfadimethoxine (SDMO) in aquatic environments. This study investigated the removal capability and mechanism involved in the removal of SDMO by hydrous ferric oxides (HFO). Results showed that SDMO removal was highly pH and ionic strength dependent. The pseudo-first-order model fitted well the kinetic results, and the value of the calculated activation energy for SDMO adsorption onto HFO was 8.6 kJ mol−1. Adsorption isotherms at varied temperatures were well described by the Langmuir model. Thermodynamic parameters (change in enthalpy > 0, change in entropy > 0, and change in Gibbs free energy < 0) calculated from the temperature-dependent sorption data revealed spontaneous and endothermic process. The exchange of the surface hydroxyl groups of HFO and the negative anions of SDMO− and the electrostatic interaction between the positively charged surface of HFO and the deprotonated imino (–N−–) accounted for the uptake of SDMO by HFO.
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Jafari, Shila, Benjamin Wilson, Minna Hakalahti, Tekla Tammelin, Eero Kontturi, Mari Lundström et Mika Sillanpää. « Recovery of Gold from Chloride Solution by TEMPO-Oxidized Cellulose Nanofiber Adsorbent ». Sustainability 11, no 5 (6 mars 2019) : 1406. http://dx.doi.org/10.3390/su11051406.
Texte intégralRésumé :
The goal of this study was to assess the sustainability of a modified cellulose nanofiber material for the recovery of precious gold from chloride solution, with a special focus on gold recovery from acidic solutions generated by cupric and ferric chloride leaching processes. TEMPO-oxidized cellulose nanofiber in hydrogel (TOCN), dry (H-TOCN, F-TOCN) and sheet form (S-TOCN) was examined for gold adsorptivity from chloride solution. Additionally, this work describes the optimum conditions and parameters for gold recovery. The data obtained in this investigation are also modeled using kinetic (pseudo first-order and pseudo second-order), isotherm best fit (Freundlich, Langmuir and Langmuir-Freundlich), and thermodynamic (endothermic process) parameters. Results demonstrate that high levels of gold removal can be achieved with TEMPO-oxidized cellulose nanofibers (98% by H-TOCNF) and the interaction characteristics of H-TOCN with gold suggests that other precious metals could also be efficiently recovered.
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Bhattarai, Pushpa, Khagendra Prasad Bohra et Megh Raj Pokhrel. « Adsorptive Removal of As(III) from Aqueous Solution ». Journal of Institute of Science and Technology 19, no 1 (8 novembre 2015) : 150–54. http://dx.doi.org/10.3126/jist.v19i1.13841.
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The iron-modified Dalbergia sissoo sawdust was synthesized by loading iron (III) onto phosphorylated Dalbergia sissoo sawdust via soaking in a ferric salt solution. Batch studies were performed at an initial concentration of 1 mg/l to evaluate the effect of parameters such as pH, equilibrium time, adsorbent dose and concentration of adsorbate. Kinetics and isotherm modeling studies demonstrated that the experimental data best fit a pseudo-first order and Langmuir isotherm model, respectively. The maximum adsorption capacity was found to be 1.33 mg/g for As(III) onto FePDSD suggesting the suitability of chemically modified Dalbergia sissoo sawdust for the adsorptive removal of As(III) from aqueous solution.Journal of Institute of Science and Technology, 2014, 19(1): 150-154
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Malki, Fatiha, Ali Alouache et Soumia Krimat. « Effects of Various Parameters on the Antioxidant Activities of the Synthesized Heterocyclic Pyrimidinium Betaines ». Indonesian Journal of Chemistry 23, no 1 (27 décembre 2022) : 90. http://dx.doi.org/10.22146/ijc.74803.
Texte intégralRésumé :
Betaine derivatives are widely used in cosmetic, industrial uses, biology and other scientific fields. Pyrimidinium betaine is a special class of bioactive heterocyclics. They have interesting antioxidant and free radical scavenging activities. This work aims to examine the influence of some parameters on the antioxidant activity of some synthesized betaines containing pyrimidine ring. Four pyrimidinium betaines: monocyclic, bicyclics, and one with a fatty alkyl chain were synthesized from condensation of 2-aminopyrimidine or amidine derivatives with malonic esters, and their antioxidant capacity was evaluated. The effects of concentration, reaction time and temperature on their antioxidant activities were investigated by three common methods: 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging, ferric reducing antioxidant power (FRAP) and β-carotene bleaching. The results showed that all pyrimidinium betaines exhibited antioxidant activities in different assays. In the DPPH and reducing power assays, antioxidant activity increased with concentration, whereas in the β-carotene/linoleic acid system, it increased with temperature. On the other hand, the DPPH assay showed an increase in antioxidant capacity over time, while the β-carotene bleaching assay showed a decrease. These results indicate that the antioxidant activity differs depending on the method used and that the various factors affect the antioxidant activity in a different order.
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Harrat, Zouaoui R., Mohammed Chatbi, Baghdad Krour, Marijana Hadzima-Nyarko, Dorin Radu, Sofiane Amziane et Mohamed Bachir Bouiadjra. « Modeling the Thermoelastic Bending of Ferric Oxide (Fe2O3) Nanoparticles-Enhanced RC Slabs ». Materials 16, no 8 (12 avril 2023) : 3043. http://dx.doi.org/10.3390/ma16083043.
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Nanoparticles, by virtue of their amorphous nature and high specific surface area, exhibit ideal pozzolanic activity which leads to the formation of additional C-S-H gel by reacting with calcium hydroxide, resulting in a denser matrix. The proportions of ferric oxide (Fe2O3), silicon dioxide (SiO2), and aluminum oxide (Al2O3) in the clay, which interact chemically with the calcium oxide (CaO) during the clinkering reactions, influence the final properties of the cement and, therefore, of the concrete. Through the phases of this article, a refined trigonometric shear deformation theory (RTSDT), taking into account transverse shear deformation effects, is presented for the thermoelastic bending analysis of concrete slabs reinforced with ferric oxide (Fe2O3) nanoparticles. Thermoelastic properties are generated using Eshelby’s model in order to determine the equivalent Young’s modulus and thermal expansion of the nano-reinforced concrete slab. For an extended use of this study, the concrete plate is subjected to various mechanical and thermal loads. The governing equations of equilibrium are obtained using the principle of virtual work and solved using Navier’s technique for simply supported plates. Numerical results are presented considering the effect of different variations such as volume percent of Fe2O3 nanoparticles, mechanical loads, thermal loads, and geometrical parameters on the thermoelastic bending of the plate. According to the results, the transverse displacement of concrete slabs subjected to mechanical loading and containing 30% nano-Fe2O3 was almost 45% lower than that of a slab without reinforcement, while the transverse displacement under thermal loadings increased by 10%.
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Ahmed, S., et S. K. Saha. « Electrochemical study of the reaction between progressively alkylated thiazine leucodyes and Fe(III) on a glassy carbon electrode ». Canadian Journal of Chemistry 74, no 10 (1 octobre 1996) : 1896–902. http://dx.doi.org/10.1139/v96-213.
Texte intégralRésumé :
An electrochemical investigation on five progressively alkylated thiazine dyes in the presence of Fe(III) ions is reported. The theory of the catalytic regeneration mechanism involving an electrode reaction followed by a coupled chemical reaction is applied to derive kinetic parameters of homogeneous reaction. The second-order rate constant for the reaction of thiazine leucodyes with Fe(III) ions was found to increase from 0.25 × 104 to 1.6 × 104 dm3 mol−1 s−1 upon monomethylation and to vary from 0.7 × 104 for the dimethyl derivative to 1.4 × 104 dm3mol−1 s−1 for the tetramethyl one. The electron-donating nature as well as the hydrophobic characteristics of the methyl group influence the kinetics of the homogeneous reaction. Key words: cyclic voltammetry, thiazine dyes, ferric ion, catalytic regeneration, kinetics
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Aguirre, Paulina, Esvar Diaz et Juan C. Gentina. « Evaluation of Parameters in the Bio-Oxidation Process of Refractory Gold Minerals ». Advanced Materials Research 825 (octobre 2013) : 364–67. http://dx.doi.org/10.4028/www.scientific.net/amr.825.364.
Texte intégralRésumé :
The mining districts located in the western mountain range in the south of Ecuador have gold minerals with refractory characteristics, which do not allow gold recovery by traditional methods used in Ecuador. Therefore, it is necessary to apply some technology that permits to obtain greater metal recovery. Bio-oxidation, as treatment of refractory ores that contain low grade of gold, offers an economic and sustainable alternative for this purpose. The objective of this research was to evaluate the effect of particle size, pulp density and concentration of inoculum and inducer (Fe+2) on the bio-oxidation of refractory gold minerals in order to maximize gold recovery of the bioleached minerals by means of a cyanidation process. The microbial consortium used in this work was collected and isolated from the Portovelo mining district corresponding mostly toAcidithiobacillus ferrooxidansandLeptospirillum ferrooxidansspecies. The Eh, final concentration of ferric ion, total iron and sulfates were measured. Finally, the bio-oxidized material was tested using cyanidation to determine the gold recovery. The results after the cyanidation tests showed that the highest gold recovery was obtained when the bio-oxidation step was conducted with 68-91 µm particle size, 15% pulp density, 20% v/v inoculum and 2 g/L of Fe2+as inducer. At those conditions, gold recovery was 68% compared to 26% obtained when no bio-oxidation step was performed, demonstrating that this process was favorable compared with traditional gold recovery processes
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Jiang, Zhen Zhen, Yang Chen et Jun Ren Zhu. « Optimization of the Coagulation Process for Kaolin and Humic Acid Removal Using Polymeric Aluminum Ferric Sulfate ». Advanced Materials Research 1088 (février 2015) : 353–57. http://dx.doi.org/10.4028/www.scientific.net/amr.1088.353.
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In the paper, the optimization of the coagulation process for Kaolin and humic acid removal using polymeric aluminum ferric sulfate (PAFS) was studied. In order to obtain the maximum turbidity and humic acid removal efficiency of Kaolin and humic acid simulated wastewater, the optimum coagulation conditions was investigated with the factors of mixing speed and time. Furthermore, mixing speed and time including parameters affecting the coagulation performance such as rapid mixing speed, rapid mixing time, slow mixing speed and slow mixing time using single factor and orthogonal array L9 (34) analysis were examined. The results showed that the optimum single factor of mixing speed and time indicated rapid mixing speed of 350 rpm, rapid mixing time of 1.0 min, slow mixing speed of 60 rpm and slow mixing time of 20 min. Then the orthogonal optimization experiment of mixing speed and time indicated maximum HA removal efficiency was 97.5% at rapid mixing speed of 350 rpm, rapid mixing time of 1.25 min, slow mixing speed of 60 rpm, and slow mixing time of 20 min.
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Murtic, Senad, Rodoljub Oljaca, Ivana Koleska, Lutvija Karic et Vida Todorovic. « Response of cherry tomato seedlings to liquid fertiliser application under water stress ». Horticultural Science 45, No. 1 (21 février 2018) : 22–28. http://dx.doi.org/10.17221/17/2017-hortsci.
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The aim of this study was to examine the impact of different liquid fertilisers on selected physiological parameters in order to evaluate the drought tolerance of cherry tomato seedlings. The following physiological parameters were investigated: total phenolic and flavonoid content, total antioxidant capacity and proline content of leaf extracts. Total phenolic and flavonoid content were determined using the Folin-Ciocalteu and aluminium chloride colorimetric methods, respectively. The ferric-reducing/antioxidant power (FRAP assay) was used to measure the total antioxidant capacity, while proline content was evaluated according to the method of Bates. The contents of proline, total phenolics and flavonoids were significantly higher in the leaves of cherry tomato seedlings exposed to water stress, which suggests that the higher synthesis of these substances by plants represents an important defence mechanism of drought tolerance. The results also indicate that the application of all the used fertilisers in accordance with the manufacturer’s instructions can significantly increase the content of phenol compounds and total antioxidant capacity of plants under normal growth conditions, thus improving survival under subsequent stress.
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Revankar, Harish N., Prasanna S. Koujalagi, Vijayendra R. Gurjar et Raviraj M. Kulkarni. « Adsorption of Chromium(VI) from Aqueous Solution using Iron Oxide Loaded Strong Base Anion Exchange Resin ». Asian Journal of Chemistry 35, no 2 (2023) : 397–405. http://dx.doi.org/10.14233/ajchem.2023.26935.
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A hybrid adsorbent (FO-Tulsion) was prepared by altering Tulsion A-62(MP), a commercial strongly basic anion-exchanging resin, with hydrated ferric oxide (HFO) particles of average crystallite size 49.6 nm and the removal of Cr6+ from water on Tulsion A-62(MP) and HFO-Tulsion was observed under optimized parameters. This study examines the effectiveness of chromium(VI) removal from water utilizing Tulsion A-62(MP) and Fe-loaded Tulsion A-62(MP) as selective sorbent materials. As the resin and HFO-ion-exchange Tulsion’s mechanism was rather easy and after 210 min of Cr6+ solution interaction, the optimum equilibrium was reached. Almost all the chromium ions was removed by the sorption process when the pH was between 4.0 and 5.0. The Freundlich and Langmuir adsorption isotherms were used to compare the equilibrium data for Cr6+ adsorption and it was found that both are highly suitable for Cr6+ adsorption. Under the same conditions, evaluation of the adsorption attainment of the prepared HFO-Tulsion and the anion resin indicated that the HFO-Tulsion had an elevated adsorption capability with a value of 207.18 mg/g than the anion resin (181.55 mg/g). The resulting hybrid resin was studied using spectroscopic and solid-state methods. Adsorption is governed by first-order reversible kinetics. It is possible that modifying anion resin with hydrated ferric oxide can greatly pick up the adsorption performance in the elimination of Cr6+ from drinking water and polluted water.
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Carbajal-De la Torre, G., N. N. Zurita-Mendez, M. A. Espinosa-Medina, A. B. Martinez-Valencia et A. Sanchez-Castillo. « Synthesis of Synthetic Hematite with Substituted Aluminum by Sol-Gel Method ». Materials Science Forum 793 (mai 2014) : 119–25. http://dx.doi.org/10.4028/www.scientific.net/msf.793.119.
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In this work, synthetic hematite with isomorphically substituted aluminum contents were obtained by the sol-gel chemical synthesis. Nanomaterials with Fe and Al contains were obtained by the sol-gel method mixing stoichiometric mixtures of ferric chloride (FeCl3) and aluminum isopropoxide Al (OC3H7)3at 75°C. The obtained sol-gel was dried at 60 oC followed by calcinations at 400, 800 and 1100 oC. The resulting powders were characterized by X-Ray diffraction and Scanning Electron Microscopy (SEM). Preliminary results showed α-Fe2O3particles into amorphous Al-O-Fe structure, and the formation of alumina with sintering temperature. SEM characterization results, showed small size particle formation in the order of 100-200 nm, however nanosize particles could be improve by chemical parameters control and ultrasonic dispersion. Also SEM observation showed the formation and homogenous distribution of minority Fe-O phase particles between Al-O-Fe phase particles.
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Rodríguez Madrera, Roberto, Ana Campa Negrillo, Belén Suárez Valles et Juan José Ferreira Fernández. « Phenolic Content and Antioxidant Activity in Seeds of Common Bean (Phaseolus vulgaris L.) ». Foods 10, no 4 (15 avril 2021) : 864. http://dx.doi.org/10.3390/foods10040864.
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Dry bean (Phaseolus vulgaris L.) is one of the most important pulses consumed in the world. Total phenolic content, total flavonoid content, total monomeric anthocyanin content and antioxidant capacity were determined, using ferric reducing antioxidant power and free radical scavenging activity, in 255 lines grown under the same environmental conditions. For all parameters analysed, there was a wide range of variability, with differences always above one order of magnitude. Phenolic compounds in beans with coloured coats were found to be more efficient antioxidants than those with completely white coats, and samples with more strongly coloured coats (red, cream, black, pink and brown) showed the highest antioxidant capacities. Based on the strong correlation detected between the variables, total phenolic content can be considered an appropriate indicator of antioxidant activity. The results provide a robust database for selecting those lines of greater functional and nutritional interest in terms of cultivation for direct consumption, for inclusions in food formulations or for use in future breeding programs.
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Dhanasekaran, P., P. M. Satya Sai, C. Anandbabu et K. K. Rajan. « Defluoridation of water by chemical impregnated Artocarpus hirsutus sawdust ». Water Supply 16, no 5 (13 avril 2016) : 1297–312. http://dx.doi.org/10.2166/ws.2016.032.
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Sawdust of Artocarpus hirsutus impregnated with ferric hydroxide and activated alumina (SFAA) has been studied for defluoridation of water. This paper presents a detailed surface characterization of the adsorbent by studying pore size distribution and surface morphology. By combining the constituents in the right proportion, an adsorbent with a well-developed pore size distribution could be synthesized. The effects of various parameters on fluoride adsorption by SFAA are investigated. The adsorption capacity of SFAA is considerably higher than that of many adsorbents including activated alumina. More importantly, the adsorption capacity remains unchanged for the pH range of 1 to 9, which also makes it attractive for wastewater treatment. Besides a higher efficiency supported by the results of column studies, this adsorbent is economic as the sawdust constitutes 40% by weight of the total adsorbent. Kinetic studies indicate that fluoride adsorption on SFAA follows pseudo second-order model. Breakthrough adsorption capacity of SFAA is 1.21 mg/g, as compared with 0.41 mg/g for activated alumina.
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Hoffmeister, D., M. Herbrecht, T. Kramm et P. Schulte. « EVALUATION OF RANDOM FOREST–BASED ANALYSIS FOR THE GYPSUM DISTRIBUTION IN THE ATACAMA DESERT ». ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences IV-3/W2-2020 (29 octobre 2020) : 25–28. http://dx.doi.org/10.5194/isprs-annals-iv-3-w2-2020-25-2020.
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Abstract. Gypsum-rich material covers the hillslopes above ∼ 1000 m of the Atacama and forms the particular landscape. In this contribution, we evaluate random forest-based analysis in order to predict the gypsum distribution in a specific area of ∼ 3000 km2, located in the hyperarid core of the Atacama. Therefore, three different sets of input variables were chosen. These variables reflect the different factors forming soil properties, according to digital soil mapping. The variables are derived from indices based on imagery of the ASTER and Landsat-8 satellite, geomorphometric parameters based on the Tandem-X World DEM™, as well as selected climate variables and geologic units. These three different models were used to evaluate the Ca-content derived from soil surface samples, reflecting gypsum content. All three different models derived high values of explained variation (r2 > 0.886), the RMSE is ∼ 4500 mg∙kg−1 and the NRMSE is ∼ 6%. Overall, this approach shows promising results in order to derive a gypsum content prediction for the whole Atacama. However, further investigation on the independent variables need to be conducted. In this case, the ferric oxides index (representing magnetite content), slope and a temperature gradient are the most important factors for predicting gypsum content.
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Xu, Rui, Xiaolong Nan, Feiyu Meng, Qian Li, Xuling Chen, Yongbin Yang, Bin Xu et Tao Jiang. « Analysis and Prediction of the Thiourea Gold Leaching Process Using Grey Relational Analysis and Artificial Neural Networks ». Minerals 10, no 9 (15 septembre 2020) : 811. http://dx.doi.org/10.3390/min10090811.
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The thiourea (TU) leaching of gold from refractory ores can be considered an alternative to cyanidation. However, the high reagent consumption causes an increase in cost, which seriously limits its use. In order to effectively reduce the TU consumption, it is necessary to analyze the influencing parameters of gold recovery and TU consumption and apply them to the prediction of the TU leaching process. This paper investigated six potential influencing parameters and used grey relational analysis (GRA) to analyze the relational degree between each parameter and gold recovery and TU consumption. Then, the artificial neural network (ANN) model was established to simultaneously predict the gold recovery and TU consumption in the TU gold leaching process. The results of the GRA indicated that the leaching time, initial pH, temperature, TU dosage, stirring speed, and ferric iron concentration were all well related to the gold recovery and TU consumption. Therefore, the incorporation of these parameters can significantly improve the ANN model validation. The predictive results noted that the prediction accuracy of gold recovery varied from 94.46% to 98.06%, and the TU consumption varied from 95.15% to 99.20%. Thus, the predicted values corresponded closely to the experimental results, which suggested that the ANN model can accurately reflect the relationship between the operational conditions and the gold recovery and TU consumption. This prediction method can be used as an auxiliary decision-making tool in the TU gold leaching process, and it has broad engineering application prospects in engineering.
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Čutović, Natalija, Petar Batinić, Tatjana Marković, Dragoja Radanović, Aleksandar Marinković, Branko Bugarski et Aleksandra Jovanović. « Physicochemical properties of winter savory extracts prepared using ultrasound-assisted extraction ». Lekovite sirovine, no 42 (2022) : 34–42. http://dx.doi.org/10.5937/leksir2242034c.
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This study aimed to assess the optimal extraction parameters, solvent-to-solid ratio, and extraction time, for ultrasound-assisted extraction of Satureja montana L. (winter savory) harvested from a 6-year-old experimental plantation. The optimization was performed in order to acquire extracts that are rich in the content of polyphenols (TPC), flavonoids (TFC), and proteins, and also exhibit strong antioxidant activity, while maintaining satisfactory physical characteristics. Besides this, the influence of UV irradiation on the physicochemical properties of the selected extracts was also analyzed. The TPC values increased with longer extraction time and higher ratio (ranging from 41.4 to 56.9 mg gallic acid equivalent (GAE)/g for the ratio 30:1, and 52.4-58.4 mg GAE/g for 40:1), and the TFC followed the same trend. Total protein content values increased with the increase in the solvent-to-solid ratio, while the extraction time had no significant influence. All used antioxidant assays showed better activities when a higher solvent-to-solid ratio has been performed. pH values ranged from 6.00 to 6.46. The extraction time and solvent-to-solid ratio did not significantly influence the conductivity, whereas the zeta potential was significantly affected. The highest density was detected in the extract acquired at a 40:1 ratio after 30 min (0.994 g/mL), and higher viscosity of the extracts attained at a 30:1 ratio compared to the parallels at a 40:1 ratio. According to the results of UV stability, UV light significantly affected the TPC, TFC, total proteins, ABTS radical scavenging, cupric, and ferric ion-reducing activities, with a positive effect on ferric ion-reducing potential, and the denisty. In conclusion, the extraction conditions that yielded the best phenolic-rich extract with good antioxidant potential and satisfactory physical properties were a 40:1 solvent-to-solid ratio and a 30 minute extraction time.
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Starowicz, Małgorzata, Anita Ostaszyk et Henryk Zieliński. « The Relationship between the Browning Index, Total Phenolics, Color, and Antioxidant Activity of Polish-Originated Honey Samples ». Foods 10, no 5 (28 avril 2021) : 967. http://dx.doi.org/10.3390/foods10050967.
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Honey is a source of sugars, amino acids/proteins, and polyphenols, which are the main substrates and reactants in the Maillard reaction. Several bioactive molecules are formed and sequestered to the brown polymeric melanoidins, resulting in a gain and loss of antioxidant function in honey. Therefore, the relationships between the browning index and total phenolic contents, color, and antioxidant activity of Polish-originated honeys, namely acacia, buckwheat, heather, linden, multiflorous, and rapeseed, obtained from three local beekeepers, were addressed in this study. The Total Phenolic Content data showed the following order: buckwheat > heather > acacia > multiflorous > linden > rapeseed. The buckwheat honey also had the highest ability to scavenge free radicals in the range of 207.1–289.3 and 40.9–52.3 µmol Trolox g−1, provided by Antioxidant Compounds Water-soluble and Ferric Reducing Antioxidant Power assays, respectively. Furthermore, a higher degree of browning was observed in dark-colored honey, such as buckwheat (3.1) and heather (1.35 mAU), than in light ones. Moreover, L* and b* parameters had a greater value in the honey of multiflorous, linden, and rapeseed, and a* was higher in buckwheat and heather. The variables of browning and TPC, ACW, and FRAP were positively correlated with each other. It can be concluded that the browning index strongly contributed to parameters of honey appearance, bioactive compound content, and antioxidant activity.
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Lee, Kang Hyun, Ye Won Jang, Hansol Kim, Jang-Seu Ki et Hah Young Yoo. « Optimization of Lutein Recovery from Tetraselmis suecica by Response Surface Methodology ». Biomolecules 11, no 2 (28 janvier 2021) : 182. http://dx.doi.org/10.3390/biom11020182.
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Microalgae have been attracting attention as feedstock for biorefinery because they have various advantages, such as carbon fixation, high growth rate and high energy yield. The bioactive compounds and lutein contained in microalgae are known to be beneficial for human health, especially eye and brain health. In this study, in order to improve the recovery of bioactive extracts including lutein from Tetraselmis suecica with higher efficiency, an effective solvent was selected, and the extraction parameters such as temperature, time and solid loading were optimized by response surface methodology. The most effective solvent for lutein recovery was identified as 100% methanol, and the optimum condition was determined (42.4 °C, 4.0 h and 125 g/L biomass loading) by calculation of the multiple regression model. The maximum content of recovered lutein was found to be 2.79 mg/mL, and the ABTS radical scavenging activity (IC50) and ferric reducing antioxidant power (FRAP) value were about 3.36 mg/mL and 561.9 μmol/L, respectively. Finally, the maximum lutein recovery from T. suecica through statistical optimization was estimated to be 22.3 mg/g biomass, which was 3.1-fold improved compared to the control group.
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Plastina, Pierluigi, Rosa Tundis, Chiara La Torre, Vincenzo Sicari, Angelo Maria Giuffré, Alessandro Neri, Marco Bonesi et al. « The addition of Capsicum baccatum to Calabrian monovarietal extra virgin olive oils leads to flavoured olive oils with enhanced oxidative stability ». Italian Journal of Food Science 33, no 1 (6 février 2021) : 61–72. http://dx.doi.org/10.15586/ijfs.v33i1.1937.
Texte intégralRésumé :
This study aimed to evaluate the influence of Capsicum baccatum L. Aji Angelo and Bishop crown cultivars to the quality parameters of flavoured olive oils (FOOs) obtained by the addition of both fresh and dried pepper powders (1%) to Dolce di Rossano and Roggianella monovarietal extra virgin olive oils (EVOOs). First, pepper extracts were investigated for their total phenolic, flavonoid, carotenoid content as well as phenolic acids, fatty acid profile, and vitamin C and E content. In order to evaluate the impact of both fresh and dried peppers on the oxidative stability of FOOs, the Rancimat test was applied. 2,2-Azinobis(3-ethylbenzothiazoline-6-sulfonic) acid (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), ?-carotene bleaching (B-CB) and ferric reducing antioxidant power (FRAP) assays were used to investigate the antioxidant potential. Bishop crown dried extracts showed the highest phenolic, carotenoid and vitamin content, whereas Aji Angelo had the highest amount of capsaicinoids. Among EVOOs, Roggianella EVOO showed the highest antioxidant activity as well as the highest induction time (39.6 h). Remarkably, FOO obtained by the addition of Bishop crown dried pepper extract to Roggianella EVOO showed a higher induction time (44.9 h) with respect to the corresponding EVOO.
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Krezhov, Kiril. « Effects of Substitution in Barium Hexaferrites BaFe12-xXxO19 (X=Co,Ti ; Sc) ». Solid State Phenomena 159 (janvier 2010) : 175–80. http://dx.doi.org/10.4028/www.scientific.net/ssp.159.175.
Texte intégralRésumé :
The short and long-range atomic and magnetic order in BaFe12-xCoxTixO19 (x=0.4, 0.7, 0.8) and BaFe10.4Sc1.6O19 prepared by soft chemistry routes were studied and compared with parent BaFe12O19 prepared by solid-state reaction. For BaFe10.3Co0.85Ti0.85O19 neutron diffraction and magnetic measurements revealed that (Co2+, Ti4+) substitution causes significant distortions in the local oxygen surrounding of ferric cation sites, while the grain-size effect on the structural parameters is considerably smaller. The thermal expansion coefficient exhibits a strong anisotropy. The refined magnetic moments for x=0.45 and 0.7 based on the five-cation sublattice block-type collinear ferrimagnetic structure of uniaxial type known as Gorter type for BaFe12O19, are considerably lower than the theoretical spin only moments, especially for the 4e and 12k sites, indicating for x = 0.7 a local noncollinearity with short-range ordering. For x = 0.85, at 10 K a block-type conical magnetic structure sets in. For BaFe10.4Sc1.6O19, combined neutron diffraction, field-dependent 57Fe Mössbauer studies and magnetic measurements show that the collinear block-type structure remains effective at 300 K and below it down to about 190 K. In the 190 – 1.6 K range we observe a temperature dependent incommensurate complex block-type conical structure.
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Kolodziej, Barbara, Sugier Danuta et Luchowska Katarzyna. « Changes of antioxidant activity and active compounds content in selected teas ». Foods and Raw Materials 8, no 1 (26 février 2020) : 91–97. http://dx.doi.org/10.21603/2308-4057-2020-1-91-97.
Texte intégralRésumé :
Our study tested 45 tea infusions classified into five groups (white, green, red, black, and other teas) for the content of total polyphenols and flavonoids, as well as antioxidant properties, by the FRAP and DPPH methods. We examined these parameters after prolongation of the brewing time from 10 to 30 min and overnight storage. The results showed that the capacity of the teas to bind free radicals was differentiated and the amount of anti-oxidant compounds depended on their nature. In terms of antioxidant activity and total polyphenol content, the tested tea types were ranked in the following order: white > green > black > red > other teas (yerba mate > rooibos). Our experiment demonstrated a positive correlation between the polyphenol content and antioxidant activity of the analyzed teas. Also, the DPPH antiradical efficiency was comparable to their ability to reduce ferric ions. The extended brewing time had a significant effect on the antioxidant activity of the infusions and the polyphenolic compounds analyzed therein. In contrast, storage of the infusions for 24 h at room temperature changed their antioxidant activity and affected the total polyphenol content.
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Manzur-Valdespino, Salvador, Esther Ramírez-Moreno, José Arias-Rico, Osmar Antonio Jaramillo-Morales, Zuli Guadalupe Calderón-Ramos, Luis Delgado-Olivares, Manuel Córdoba-Díaz, Damián Córdoba-Díaz et Nelly del Socorro Cruz-Cansino. « Opuntia ficus-indica L. Mill Residues—Properties and Application Possibilities in Food Supplements ». Applied Sciences 10, no 9 (7 mai 2020) : 3260. http://dx.doi.org/10.3390/app10093260.
Texte intégralRésumé :
Recently, industry has been focusing on the development of new products made from food by-products in order to reduce and take advantage of food wastes. The objective of this study was to evaluate tablet formulations developed by mixing two commercial excipients, microcrystalline cellulose (M) and α-lactose-monohydrate (L), added with powder from residues (mesocarp and pericarp) of green and red (G and R) cactus pear fruit (Opuntia ficus-indica L. Mill), having the following formulations: green with microcrystalline cellulose (GM), green with lactose (GL), red with microcrystalline cellulose (RM), and red with lactose (RL). The results showed lower disintegration times for the tablets with microcrystalline cellulose. The fiber functional properties presented good values for lipid and water holding capacity. There was a higher total phenolic content (TPC) in formulations with green cactus pear residue powder with microcrystalline cellulose and lactose (GM and GL, respectively), but the DPPH and ferric reducing/antioxidant power (FRAP) values were higher in the formulations with red cactus pear residues (RM and RL), while ABTS values were similar among all formulations. In conclusion, tablets made from Opuntia residues are proposed as a product of interest for the food supplement industry because of the good quality parameters and the functional and antioxidant properties that they provide.
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Gul, Melek, et Serpil Eryılmaz. « Synthesis, Antioxidant Activity and Theoretical Investigation of Isoxazolines Derivatives of Monoterpenoids ». Letters in Organic Chemistry 16, no 6 (23 avril 2019) : 501–10. http://dx.doi.org/10.2174/1570178616666181226154540.
Texte intégralRésumé :
The 3+2 cycloaddition reactions are important to generate five-membered heterocyclic compounds as well as altering biological activity effects based on structure. In the study, we synthesized new isoxazoline derivatives of different monoterpenoids and examined the structure analysis using spectroscopical analysis methods, reveal changes in the theoretical analysis related to the biological activity. These new compounds exhibit antioxidant activities; DPPH radical scavenging, ferric reducing, metal chelating activities which are significantly higher than the related commercial monoterpenoids. Theoretical approaches on the compounds containing isoxazole moiety have been performed by the DFT/B3LYP/method, 6-31G(d,p) basis set in the ground state. The global and local chemical reactivity properties of the compounds were investigated by considering the values of electronegativity, global hardness-softness, electronic chemical potential, electrophilicity index and condensed Fukui functions, local softness and local electrophilicity index. Furthermore, total energy, FMOs energy values and the dipole moment (µ), mean polarizability (α), and first order hyperpolarizability (β) values were analysed at the theoretical level to examine the polarizability characteristics of the compounds. The antioxidant activity values of the newly synthesized compounds were compared with a finding of the computational study. The results obtained exhibited good correlation on some parameters.
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Lotito, V., G. Mininni et L. Spinosa. « Models of Sewage Sludge Conditioning ». Water Science and Technology 22, no 12 (1 décembre 1990) : 163–72. http://dx.doi.org/10.2166/wst.1990.0111.
Texte intégralRésumé :
Models of sewage sludge conditioning are needed in order to assess the type of chemicals to be preferred and the optimal dosages. Laboratory and pilot tests were carried out with organic and inorganic chemicals for determining their influence on sludge parameters and equipment performance. A new parameter, named “Specific Resistance to Centrifugation”, for evaluating sludge centrifugability was developed. The pilot tests confirmed that satisfactory solids recoveries can be obtained when the value of this parameter is of 20-30 s. A correlation was also found between the “Specific Resistance to Centrifugation” and dosage, molecular weight and charge density of polyelectrolytes. Other correlations were determined for Specific Resistance to Filtration and compressibility coefficient. In conditioning by inorganic chemicals it was found that ferric chloride mainly influences the specific resistance, while lime the compressibility coefficient. Due to some discrepancies between the classical theory of filtration and actual results of pilot tests, a new parameter called “Average Specific Resistance to Filtration” was proposed. As far as beltpress operation is concerned, a laboratory test was defined thus allowing the drainage phase and the compression one to be simulated. The final cake concentration can be also predicted and it was found a good agreement with the actual experimental values.
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BARRIUSO, E., J. M. PORTAL et F. ANDREUX. « CINÉTIQUE ET MÉCANISME DE L'HYDROLYSE ACIDE DE LA MATIÈRE ORGANIQUE D'UN SOL HUMIFÈRE DE MONTAGNE ». Canadian Journal of Soil Science 67, no 3 (1 août 1987) : 647–58. http://dx.doi.org/10.4141/cjss87-061.
Texte intégralRésumé :
From the surface horizon of an organic-rich mountain soil, humic and fulvic acids, and organo-mineral compounds including clay and hydroxy-metal colloids, were separated and purified. Each of these fractions was hydrolyzed in 3.0 M HCl under reflux, then the reaction parameters related to the solubilization of carbon and nitrogen and to the kinetics of hydrolysis were calculated. Acid hydrolysis was interpreted as the result of two successive steps: first a rapid electrophilic attack of heteroatomic C-O and C-N bonds by protons, then a slow nucleophilic hydration of the protonated bonds. Electron delocalization in these bonds, which increased with the polycondensation degree of organic compounds, and with their adsoprtion on mineral surfaces, resulted in an increase in their stability to hydrolysis. Fulvic acids were found to be the less stable material, and lead to predominantly anionic hydrolysis products. Clay-sized humin was the most stable material and yielded mainly cationic hydrolysates. The stability to hydrolysis and the humification degree of organic matter in the fractions generally coincided, and decreased in the following order: fine clay-sized humin > alkali dispersible organo-mineral colloids > > humic acids > hydroxy-ferric organic colloids > hydroxy-aluminium organic colloids = fulvic acids. Key words: Organo-mineral complex, humic substances, acid hydrolysis, carbon, nitrogen
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Opalić, M., Z. Domitran, D. Komes, A. Belščak, D. Horžić et D. Karlović. « The Effect of Ultrasound Pre-Treatment and Air-Drying on the Quality of Dried Apples ». Czech Journal of Food Sciences 27, Special Issue 1 (24 juin 2009) : S297—S300. http://dx.doi.org/10.17221/606-cjfs.
Texte intégralRésumé :
In order to develop environmentally sound, energy inexpensive and well scalable drying techniques that maintain high quality of dried fruit, optimisation of integrated process (ultrasound and air-drying) in the production of dried apples was conducted. Selected quality parameters of fresh and dried apples (variety Goldparmâne) resulting from different duration of ultrasonic pre-treatment and air-drying were compared. Sugars were determined spectrophotometrically using an enzymatic method. Content of total phenols and flavonoids was determined spectrophotometrically with the Folin-Ciocalteau assay, while the antioxidant capacity was evaluated by using ABTS (2,2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) and FRAP (Ferric Reducing/Antioxidant Power) assays. Sensory properties of dried apples were investigated according to the Quantitative Descriptive Analysis. In combination with the same air-drying conditions, prolonged ultrasound pre-treatment led to a decrease in total phenols and flavonoids, as well as in the antioxidant capacity of dried apples. Difference in drying time had no significant effect on the content of total phenols and flavonoids, as well as antioxidant capacity. The sample dried without the ultrasound pre-treatment was evaluated as the most sensory acceptable. The content of glucose and fructose correlated well with total phenols and flavonoids, as well as with antioxidant capacity of apple samples.
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Sarkar, Atreyi, et Uma Ghosh. « Optimization of the extraction of natural phenolic antioxidants from the seeds of Tamarindus indica L. - an undervalued by product of food processing - using response surface methodology ». Acta Biologica Szegediensis 62, no 1 (23 août 2018) : 67–74. http://dx.doi.org/10.14232/abs.2018.1.67-74.
Texte intégralRésumé :
The seeds of Tamarindus indica are known to possess a wide range of phenolic compounds with high antioxidant activity as measured by the ferric reducing antioxidant power (FRAP). In the present study, the optimum conditions for the extraction of crude phenolic antioxidants from Tamarind seed were determined using response surface methodology (RSM). A central composite design (CCD) was used to investigate the effects of four independent variables, namely concentration of extractable solids in solvent (g/ml; X1), extraction time (h; X2), extraction temperature (°C; X3) and solvent concentration (%, v/v; X4) on the responses of total polyphenol content (TPC) and FRAP. The CCD consisted of 30 experimental runs. A second-order polynomial model was used for predicting the responses. Canonical analysis of the surface responses revealed that the predicted optimal conditions for the maximal yield of TPC and FRAP were concentration of extractable solids in solvent of 0.049 g/ml, extraction time of 3.24 h, extraction temperature of 45 °C and a solvent concentration of 50%. The experimental values in the optimised condition coincided with the predicted ones within a 95% confidence interval, hence indicating the suitability of the model and the success of RSM in optimizing the extraction parameters.
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Chiavola, Agostina, Emilio D’Amato et Camilla Di Marcantonio. « Comparison of Adsorptive Removal of Fluoride from Water by Different Adsorbents under Laboratory and Real Conditions ». Water 14, no 9 (29 avril 2022) : 1423. http://dx.doi.org/10.3390/w14091423.
Texte intégralRésumé :
The fluoride removal capability of six different adsorbents (four commercial, i.e., titanium dioxide-TiO2, ArsenXPnp-A33E, granular activated carbon (GAC) and granular ferric hydroxide (GFH), and two laboratory media, i.e., nano-fine media and nano-granular media) was determined under batch conditions using synthetic and real contaminated water containing arsenic and vanadium. The kinetic and equilibrium characteristics of the adsorption process under different operating conditions (pH value, initial fluoride concentration, adsorbent dosage, water composition) were obtained. Among the tested adsorbents, TiO2 showed the highest adsorption capacity; it was also capable of reducing fluoride concentration below the limit set for drinking water without pH control. TiO2 still remained the best adsorbent in the treatment of real contaminated groundwater, where it was also capable of efficiently removing both arsenic and vanadium. The other adsorbents were capable of achieving the same fluoride reduction, although only for acid pH. The nano-sized laboratory media showed an adsorption removal efficiency below that of TiO2 but superior to that of A33E, GAC and GFH. Among the investigated parameters, the removal efficiency was mainly affected by adsorbent dosage and pH. The pseudo-second order model best fitted the kinetic experimental data of all the media. The maximum adsorption capacity predicted by this model was in the following decreasing order: TiO2 > A33E > GAC > GFH. The removal capability of all the media drastically decreased due to the presence of competitive ions and unfavorable pH conditions. The best isotherm model changed depending on the type of adsorbent and pH conditions.
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Villota, Natalia, Luis Miguel Camarero, Jose Maria Lomas et Mikel Legaristi. « Kinetic Modelling of Photoconversion of Phenol by a Photo-Fenton Reagent and UV ». International Journal of Chemical Reactor Engineering 12, no 1 (1 janvier 2014) : 405–16. http://dx.doi.org/10.1515/ijcre-2013-0130.
Texte intégralRésumé :
Abstract This study analyses the oxidation of phenol using Fenton reagent in presence of ultraviolet light, enhancing the mineralization capacity of the treatment. Phenol oxidation generates reaction intermediates more toxic and refractory than phenol itself. Thus, the reaction must be carried out under harder conditions, leading these compounds to biodegradable acids that can be dumped into public sewages. Then, this paper considers a complete kinetic modelling of the phenol oxidation stages, differentiating the formation rate of species generated through ortho, meta and para pathways. The model is based on a mechanism of series reactions, wherein a first step degrades into dihydroxylated intermediates (catechol, resorcinol and hydroquinone). A second stage leads to tri-hydroxylated rings (pyrogallol) and benzoquinones (o-benzoquinone and p-benzoquinone), and both species may coexist in the reaction mixture. Next, if conditions are sufficiently oxidizing, they decompose into biodegradable organic acids (muconic, formic or acetic acids). In this mechanism, the parallel reactions, due to the presence of the metal catalyst, are considered. So, on one hand, there is a formation of metal complexes between species ortho-substituted and ferric ions from the catalyst. On the other hand, there is a precipitation of part of the initial catalyst as ferric hydroxide, due to the presence of ultraviolet light, which is determined by the operation pH. Studies have been performed on the selectivity of the oxidation in function of the reaction conditions. Then, when operating with pH = 3.0, oxidation was favoured via ortho-substituted compounds. Treatment is advisable within Pho = 100–300 mg/L, being necessary to apply molar ratios of oxidant above R = 6.0 mol H2O2/mol C6H5OH to degrade these intermediates. Moreover, kinetic constants of formation of generated species are estimated, supposing that follows an evolution comparable to first-order reactions. Analysis checks that these kinetic constants present some relation to the operating conditions. In this way, a mathematical estimation is presented, showing the dependence of the kinetics on the parameters controlling the process (pH, initial concentration of phenol, oxidant molar ratio, catalyst dosage and temperature). As a result, the behaviour of the system can be predicted within the considered range.
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Krouma, Abdelmajid. « Differential response of pea (Pisum sativum L.) genotypes to iron deficiency in relation to the growth, rhizosphere acidification and ferric chelate reductase activities ». June 2021, no 15(06):2021 (10 juin 2021) : 925–32. http://dx.doi.org/10.21475/ajcs.21.15.06.p3171.
Texte intégralRésumé :
Calcareous soils are known problematic lands for agricultural systems because of the low availability of nutrients, particularly iron (Fe). The so-called strategy I plant (e. g. Pea, Pisum sativum L.) which groups dicotyledons and monocots other than grasses, developed root membrane activities that contribute to the improvement of Fe availability. Among the functions considered to be a critical phase in iron absorption is rhizosphere acidification by H-ATPase and Fe(III) reduced by Fe(III) chelate reducctase (FeCR). In order to experimentally investigate the importance of root FeCR in Fe nutrition, its relationship with rhizosphere acidification and the genotypic differences in response to iron deficiency in pea (Pisum sativum L.), a glasshouse experiment was conducted hydroponically on four genotypes Merveille de Kelvedon (MK); Lincoln (Lin); Douce de Provence (DP) and Alexandra (Alex). Plants of each genotype were distributed into two plots, the first one received full nutrient solution (+ Fe), the second one received nutrient solution devoid of iron (- Fe). Plant growth, Fe distribution, SPAD index and root acidification and ferric chelate reductase activities were evaluated. Fe deficiency decreased plant growth and SPAD index along with the significant increase of H-ATPase and FeCR activities. Some genotypic differences were observed as follows; Alex showed high tolerance to Fe deprivation as compared to other genotypes. Important H-ATPase and FeCR activities, high Fe use efficiency and adequate membrane efficiency are the main reasons for this tolerance. These physiological parameters could be used as tools of tolerance for further breeding programs
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Mahmoud, Ahmed S., Mohamed K. Mostafa et Robert W. Peters. « A prototype of textile wastewater treatment using coagulation and adsorption by Fe/Cu nanoparticles : Techno-economic and scaling-up studies ». Nanomaterials and Nanotechnology 11 (janvier 2021) : 184798042110411. http://dx.doi.org/10.1177/18479804211041181.
Texte intégralRésumé :
This study aims to investigate the efficiency of a pilot prototype system comprising coagulation/flocculation, filtration, and nano-bimetallic iron/copper (Fe/Cu) degradation and adsorption units for the removal of chemical oxygen demand (COD), biological oxygen demand (BOD), color, total nitrogen (TN), total phosphorus (TP), and TSS from real textile wastewater. The total removal efficiencies of the system were 96, 98, 82, 69, 88, and 97%, respectively, using 0.5 g/L ferric chlorides as a coagulant under an optimum adsorption condition of pH 6.0, nano-dosage 1.4 g/L, contact time 80 min, and stirring rate 250 r/min at room temperature. Adsorption isotherms indicated that the removal of COD and TP obeys both Koble–Corrigan and Freundlich adsorption models, removal of color obeys both Koble–Corrigan and Hill adsorption models, and removal of TN and TSS obeys Koble–Corrigan and Khan models, respectively. Avrami kinetic models adequately describe the adsorption data for COD, BOD, TN, and TSS, while pseudo-second-order and intraparticle models described the removal mechanism of color and TSS, respectively. An artificial neural network (ANN) with r2-value exceeding 0.98 is accurate and can be used with confidence in predicting removal efficiencies of the targeted parameters. Sensitivity analysis results showed that the initial concentration was the most influential parameter for TSS removal with relative importance greater than 25%, while the bimetallic Fe/Cu dosage was the most influential factor for all other studied parameters with relative importance greater than 40%. The total treatment cost of the proposed system per m3 after scaling up was found to be US$4.5 for reuse of the treated water for the irrigation of forest trees.
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Koczka, Noémi, Éva Stefanovits-Bányai et Attila Ombódi. « Total Polyphenol Content and Antioxidant Capacity of Rosehips of Some Rosa Species ». Medicines 5, no 3 (4 août 2018) : 84. http://dx.doi.org/10.3390/medicines5030084.
Texte intégralRésumé :
Background: Rosehips, the fruits of Rosa species, are well known for their various health benefits like strengthening the immune system and treating digestive disorders. Antioxidant, anti-inflammatory, and cell regenerative effects are also among their health enhancing impacts. Rosehips are rich in compounds having antioxidant properties, like vitamin C, carotenoids, and phenolics. Methods: Total polyphenol content (Folin-Ciocalteu’s method), and in vitro total antioxidant capacity (ferric-reducing ability of plasma, FRAP) in rosehips of four Rosa species (R. canina, R. gallica, R. rugosa, R. spinosissima) were determined and compared. Ripe fruits were harvested at two locations. Water and ethanolic extracts of dried fruit flesh were analyzed. Results:R. spinosissima had the highest total phenolic content and antioxidant capacity, significantly higher than the other investigated Rosa species. Both parameters were reported in decreasing order for R. spinosissima > R. canina > R. rugosa > R. gallica. Ethanolic extracts of rosehips showed higher phenolic content and antioxidant activity than water extracts. Antioxidant properties were influenced by the growing site of Rosa species. Conclusions: This study indicates that R. spinosissima exhibited the greatest phenolic and antioxidant content, and therefore can be used as a reliable source of natural antioxidants, and serve as a suitable species for further plant breeding activities. Furthermore, investigations of various Rosa species for their antioxidant properties may draw more attention to their potential as functional foods.
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Roushdy, Mai Hassan. « Heterogeneous Biodiesel Catalyst from Steel Slag Resulting from an Electric Arc Furnace ». Processes 10, no 3 (25 février 2022) : 465. http://dx.doi.org/10.3390/pr10030465.
Texte intégralRésumé :
Biodiesel is one of the most environmentally friendly and renewable fuels, as it is a non-polluting fuel and is made from living resources, such as vegetable oils. The steel industry generates a variety of solid wastes, including electric arc furnace slag (EAFS). The synthesis of biodiesel from waste sunflower cooking oil was examined in this study, utilizing EAFS as a catalyst, which mainly contains ferric and ferrous oxides, calcium oxide, and silica. To evaluate their impact on biodiesel production, four independent variables were chosen: temperature (50–70 °C), catalyst loading (1–5%), methanol-to-oil (M:O) molar ratio (5–20), and time (1–4 h). The response surface methodology (RSM) was used to examine the impact of independent variables on reaction response, which is the biodiesel yield. This process was carried out using a design expert program by central composite design (CCD). A model was constructed, and showed that the biodiesel yield was directly proportional to all independent reaction parameters. The predicted model’s adequacy was investigated using analysis of variance (ANOVA), which showed that it is an excellent representative of the results. The optimization of reaction conditions was investigated in order to maximize biodiesel yield at minimal reaction temperature and time, achieving a 94% biodiesel yield at a 20:1 M:O molar ratio, 5% catalyst loading, 55.5 °C reaction temperature, and 1 h reaction time.
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Garcia-Vaquero, Marco, Gaurav Rajauria, Brijesh Tiwari, Torres Sweeney et John O’Doherty. « Extraction and Yield Optimisation of Fucose, Glucans and Associated Antioxidant Activities from Laminaria digitata by Applying Response Surface Methodology to High Intensity Ultrasound-Assisted Extraction ». Marine Drugs 16, no 8 (30 juillet 2018) : 257. http://dx.doi.org/10.3390/md16080257.
Texte intégralRésumé :
The objectives of this study were to employ response surface methodology (RSM) to investigate and optimize the effect of ultrasound-assisted extraction (UAE) variables, temperature, time and amplitude on the yields of polysaccharides (fucose and total glucans) and antioxidant activities (ferric reducing antioxidant power (FRAP) and 1,1-diphenyl-2-picryl-hydrazyl radical scavenging activity (DPPH)) from Laminaria digitata, and to explore the suitability of applying the optimum UAE conditions for L. digitata to other brown macroalgae (L. hyperborea and Ascophyllum nodosum). The RSM with three-factor, four-level Box-Behnken Design (BBD) was used to study and optimize the extraction variables. A second order polynomial model fitted well to the experimental data with R2 values of 0.79, 0.66, 0.64, 0.73 for fucose, total glucans, FRAP and DPPH, respectively. The UAE parameters studied had a significant influence on the levels of fucose, FRAP and DPPH. The optimised UAE conditions (temperature = 76 °C, time = 10 min and amplitude = 100%) achieved yields of fucose (1060.7 ± 70.6 mg/100 g dried seaweed (ds)), total glucans (968.6 ± 13.3 mg/100 g ds), FRAP (8.7 ± 0.5 µM trolox/mg freeze-dried extract (fde)) and DPPH (11.0 ± 0.2%) in L. digitata. Polysaccharide rich extracts were also attained from L. hyperborea and A. nodosum with variable results when utilizing the optimum UAE conditions for L. digitata.
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Borrajo, Paula, Mirian Pateiro, Mohammed Gagaoua, Daniel Franco, Wangang Zhang et José Manuel Lorenzo. « Evaluation of the Antioxidant and Antimicrobial Activities of Porcine Liver Protein Hydrolysates Obtained Using Alcalase, Bromelain, and Papain ». Applied Sciences 10, no 7 (27 mars 2020) : 2290. http://dx.doi.org/10.3390/app10072290.
Texte intégralRésumé :
In order to make the by-products generated from the porcine industry more valuable, pig livers were used in this trial to obtain protein hydrolysates. Three proteases (alcalase, bromelain, and papain) were utilized for enzymatic hydrolysis with two different durations, 4 and 8 hours. Ultrafiltration process was used for the recovery of the extracts, employing three different membrane pore sizes (30, 10, and 5 kDa). The porcine livers contained considerable amounts of protein (19.0%), considering they are almost composed of water (74.1%). The antioxidant activity of the obtained hydrolysates was investigated using four antioxidant methods (2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, 2-2′-Azino-di-[3-ethylbenzthiazoline sulfonate] (ABTS) radical scavenging activity, ferric reducing antioxidant power assay (FRAP), and oxygen radical absorbance capacity assay (ORAC)). Antibacterial properties were also measured against Gram-negative and Gram-positive bacteria. Results indicated that the three studied factors (type of enzyme, membrane pore size, and time) significantly affected the parameters evaluated. Hydrolysates obtained at 8 hours with alcalase had the best antioxidant properties. The 30 kDa alcalase extracts exhibited the highest DPPH (562 µg Trolox/g), FRAP (82.9 µmol Fe2+/100 g), and ORAC (53.2 mg Trolox/g) activities, while for ABTS the 10 kDa alcalase showed the higher values (1068 mg ascorbic acid/100 g). Concerning the antibacterial activity, 30 kDa hydrolysates obtained with bromelain for 4 hours exhibited the highest antimicrobial capacity, providing an inhibition of 91.7%.
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Liang, Jianjun, Meiling Liu et Yufei Zhang. « Cd(II) removal on surface-modified activated carbon : equilibrium, kinetics and mechanism ». Water Science and Technology 74, no 8 (16 juillet 2016) : 1800–1808. http://dx.doi.org/10.2166/wst.2016.338.
Texte intégralRésumé :
Commercial pulverous activated carbon (AC-0) was modified through two steps: oxidize AC-0 acid firstly, impregnate it with iron using ferric chloride secondly. Orthogonal experiment was conducted then to prepare modified activated carbon with high Cd(II) adsorption capacity (ACNF). Batch adsorption experiments were undertaken to determine the adsorption characteristics of Cd(II) from aqueous solution onto AC-0 and ACNF and the effect of pH, contact time and initial Cd(II) concentration. The results indicate that: the adsorption behavior of Cd(II) on ACNF can be well fitted with Langmuir model, and the maximum adsorption capacity of ACNF was 2.3 times higher than that of AC-0, supporting a monolayer coverage of Cd(II) on the surface. The kinetics of the adsorption process can be described by pseudo-second-order rate equation very well, and the adsorption capacity increased from 0.810 mg/g to 0.960 mg/g after modification. Compared with AC-0, the kinetic parameters of ACNF showed a higher adsorption rate through the aqueous solution to the solid surface and a lower intraparticle diffusion rate. Surface modification resulted in a lower Brunauer–Emmett–Teller (BET) surface area and pore size because of the collapse and blockage of pores, according to the X-ray diffraction (XRD) analysis, while the total number of surface oxygen acid groups increased, and this was supposed to contribute to the enhanced adsorption capacity of modified activated carbon.
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Yeboah, Edward, Gideon Asamoah, Patrick Ofori, Ben Amoah et Kwaku Osei Adu Agyeman. « Method of biochar application affects growth, yield and nutrient uptake of cowpea ». Open Agriculture 5, no 1 (12 août 2020) : 352–60. http://dx.doi.org/10.1515/opag-2020-0040.
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AbstractBiochar produced from pyrolysis of organic materials has been found to improve plant growth by improving the physical and chemical characteristics of the soil as well as enhancing the sequestration of carbon dioxide that would release into the atmosphere through the decomposition of organic residues. However, there is scanty information on the methods used to apply biochar in order to optimize the benefits of biochar use for agricultural production. In view of this, a field study was carried out at the experimental field of CSIR – Soil Research Institute, Kumasi, to assess the effect of method of biochar application on the growth, yield and nutrient uptake of cowpea (Vigna unguiculata) in a moderately acidic sandy Ferric Acrisol. The experiment was set up using a Randomized Complete Block Design with three replications. The treatments imposed were as follows: control, broadcasting, spot and ring methods of application. The parameters assessed included growth and yield data as well as nitrogen and phosphorus uptake in shoots and grains. The data collected were subjected to analysis of variance using Genstat 12th edition. The results showed that the spot and ring methods of application significantly enhanced height, girth, nodule number and dry weight, shoot biomass and grain yield as well as nitrogen and phosphorus contents in shoots and grains when compared with the broadcasting method and control. This study therefore recommends the spot and ring methods of biochar application for adoption in cowpea production for enhanced growth, yield and nitrogen and phosphorus uptake.
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Acosta, Mauricio, Pedro A. Galleguillos, Sabrina Marín, Clement Chibwana, Hannes Strauss et Cecilia Demergasso. « Blue-Copper Proteins : Expression of Coding Genes from Sulfobacillus Spp. and Iron Oxidation in Column Bioleaching Tests ». Advanced Materials Research 1130 (novembre 2015) : 333–37. http://dx.doi.org/10.4028/www.scientific.net/amr.1130.333.
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In bioleaching, the chemiolithotrophic community plays an important role as oxidizers of sulfur compounds and ferrous iron. Ferrous iron oxiding microorganisms are key players in the process, as ferric iron is absolutely required to solubilize metal sulfide ores. Members of the Sulfobacillus genus (able to oxidize ferrous iron) were predominant (22 - 95%) in a chalcopyrite bioleaching columns test. In order to obtain new insight about the mechanism of iron oxidation in Sulfobacillus we investigated the presence and expression of genes potentially related to iron oxidation by Sulfobacillus, especially the group of the so-called blue-copper proteins rusticyanin (rus) and sulfocyanin (soxE) in the course of the experiment. The physicochemical parameters and the population dynamics were monitored periodically in the columns and the metatranscriptome was analyzed by using pyro-sequencing. The average temperature inside the column ranged from 22 to 57 °C and the Fe(II) oxidation rate at 45 °C varied between 8 and 42 mg L-1h-1 along 300 days of operation. The metatranscriptomic analysis reveals an over-expression of 9-13 folds of the putative rus and soxE genes in four strains of Sulfobacillus spp. when the Sulfobacillus proportion in the column was >80% and the Fe(II) oxidation rate measured at 45 °C reached 10 mg L-1h-1. Some cytochromes from the electron transport chain were also over-expressed, on a range of 7 - 10 folds under those operational conditions. These results support the hypothetical participation of blue-copper proteins in the iron oxidation pathway of Sulfobacilli. Culture assays and more specific expression analysis are necessary in order to confirm this hypothesis. In addition, we attempt to establish the relationship between rusticyanin and sulfocyanin genes and perform a protein sequence analysis that allows us to infer the actual function of these proteins in Sulfobacillus species.
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Soproni, Vasile Darie, Livia Bandici, Alin Cristian Teusdea, Francisc Ioan Hathazi, Mircea Nicolae Arion, Carmen Otilia Molnar, Teodor Leuca, Claudia Andrada Dalea et Simona Ioana Vicas. « Phenolic Content, Antioxidant Capacity, and Browning Impact of Apple Slices during Microwave Drying : A Chemometric Approach ». Processes 11, no 6 (23 mai 2023) : 1601. http://dx.doi.org/10.3390/pr11061601.
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Apples represent a category of products frequently consumed by people, owing both to their beneficial effects on human health and to their antioxidant effects. Microwave (MW) treatment is a simple and fast method that can be used successfully in the food industry to obtain dry apple slices, rich in bioactive compounds and with a pleasant aspect. This study presents the effect of applying microwave treating to apple slices from two cultivars (Golden Delicious and Idared), for three, four, and five minutes, respectively, at a power of 450 W, in order to reduce the browning effect. For this purpose, the browning index (BI), chromatic parameters (CIE L*a*b*), total phenolic content (Folin-Ciocâlteu method), and antioxidant capacity (by Ferric Reducing Antioxidant Power (FRAP assay) were evaluated in the case of apple slices before and after MW treatment. Based on the results obtained, it can be argued that the microwave treatment results in a significant increase in the total phenolic content and enhances antioxidant capacity in the case of both apple cultivars. Apples from the Idared cultivar have a higher total phenolic content than apples from the Golden cultivar, and this concentration increased by 56.14% and 48.9%, respectively, after MW treatment. In terms of antioxidant capacity, Idared apples also recorded a higher value compared to Golden cultivars. According to the results of the multivariate analysis, there are variations between the two apple categories with regard to the phenolic content and the browning process; browning was inhibited at the five-minute exposure to microwaves. The apple processing domain may use our findings in order to produce high-quality finished products, with a pleasant aspect, which retain the bioactive compounds of the fruit.
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Ratnasooriya, C. C., H. P. V. Rupasinghe et A. R. Jamieson. « Juice quality and polyphenol concentration of fresh fruits and pomace of selected Nova Scotia-grown grape cultivars ». Canadian Journal of Plant Science 90, no 2 (1 mars 2010) : 193–205. http://dx.doi.org/10.4141/cjps09137.
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Juice, fresh fruit and pomace of 10 selected Nova Scotia-grown grape cultivars (five table and five wine cultivars) were evaluated for their physicochemical parameters and major phenolic compounds to determine their suitability in use for developing functional beverages. Colour intensity, total soluble solids, total anthocyanin concentration and antioxidant capacity were significantly higher in juice of wine grape cultivars than in juice of table grape cultivars. Titratable acidity was not significantly different among the juice of the two categories. In juice, a high positive correlation was observed between total phenolic concentration measured using Folin-Ciocalteu assay and antioxidant capacity measured using oxygen radical absorbance capacity (ORAC) (r = 0.87) and ferric reducing antioxidant power (FRAP) (r = 0.95). Flavan-3-ols, stilbenes and anthocyanin concentrations were significantly higher in fruits of wine grape cultivars, while the distribution of flavonols was highly variable in two categories. The descending order of total phenol concentration in fruits was: Lucie Kuhlman > Baco Noir > Marechal Foch > Castel 19637 > Sovereign Coronation > Leon Millot > Van Buren > Swenson Red > Suffolk Red > Reliance. The average overall concentrations of flavan-3-ols, flavonols, stilbenes and anthocyanins in pomace were 40, 90, 60 and 50% higher than that of the fresh fruits. Among the cultivars evaluated, Castel 19637 and Lucie Kuhlman showed the greatest potential for the development of a functional beverage; however, further characterization on sensory quality attributes is required.Key words: Grape, juice, pomace, antioxidant capacity, anthocyanin, stilbenes, flavan-3-ols, flavonols
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Drakou, Athina, Christos Poziopoulos, Alexandra Margeli, Ioannis Papassotiriou et Demetrios Vlahakos. « Assessment of Serum Bioactive Hepcidin-25, Soluble Transferrin Receptor and Their Ratio in Predialysis Patients : Correlation with the Response to Intravenous Ferric Carboxymaltose Administration ». Blood 126, no 23 (3 décembre 2015) : 949. http://dx.doi.org/10.1182/blood.v126.23.949.949.
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Abstract Background: No reliable biomarker exists to predict responsiveness to intravenous (IV) iron (Fe) in iron deficient patients with chronic kidney disease (CKD). Our aim was to investigate if Hepcidin-25 (Hepc25) and soluble Transferrin Receptor (sTfR) and their Ratio sTfR/Hepc25 ratio prior to treatment can make a distinction between those predialysis patients with and those without adequate erythropoiesis after administration of IV ferric carboxymaltose (FCM). Patients and methods: In this prospective study we enrolled 78 stable stage III-IV CKD patients with iron deficiency (serum ferritin levels lower than 100µg/L) treated with IV FCM 1000mg/100ml NaCl-0.9% and infused over a period of 20min. Patients were divided in two groups according to hemoglobin (Hb) increase within a month after treatment. The responders (Group R, n=40), showed above 1g/dL increase in Hb concentration. The non-responders (Group NR, n=38) had no such a favorable reaction. Patient data, clinical information and blood samples were collected prior to IV iron administration. Hematologic analysis was performed using a hematogy analyzer. Blood chemistry, including measurements of renal, nutrition and inflammation markers along with measurements of Hepc25, IL-6 and sTfR were performed using appropriate techniques. Receiver Operating Curve (ROC) analysis was applied in order to evaluate the diagnostic potential of Hepc25 and sTfR/Hepc25 ratio and conclusions about the specificity and sensitivity were drawn. Results: As shown in Table 1, there were no significant differences at baseline between responders and non-responders in demographic and clinical parameters. No significant differences were revealed for serum creatinine, e-GFR, folic acid (FA), vitamin B12, hs-CRP and IL-6, with the notable exception of ferritin and Hepc25 levels that were lower and sTfR and sTfR/Hepc25 ratio that were higher in the responders as compared to non-responders (Table 1). Diagnostic efficacy was analyzed by ROC analysis. Cut off point of 1.49 for Hepc25 had sensitivity 84% and specificity 48%, and cut off point of 1.21 for sTfR/Hepc25 ratio had sensitivity 82% and specificity 52% to predict correctly response to Fe therapy (Table 2). Conclusions: These results suggest that lower Hepc25 and ferritin levels, as well as higher sTfR and sTfR/Hepc25 ratio were significant predictors of favorable hemoglobin response within a month after IV administration of FCM in CKD patients. Further in vitro and in vivo experiments and clinical studies in a larger population of patients are needed to better elucidate the role of Hepc25 and sTfR/Hepc25 ratio in iron deficiency anemia in CKD. Table 1. Demographic, clinical and biochemical parameters in responders vs non-responders. Group R (n=40 Group NR (n=38) Age (years) 72.7±11.2 74.5±10.3 NS Gender (M /F) 27:13 25:13 NS Medications -RAS inhibitors 21(27%) 19(24%) NS rh EPO 1(27%) 20(26%) NS CCB 10(13%) ) 11(14% NS BMI (Κg/m2) 25.5±3.3 25.1±3.4 NS Comorbidities -Cardiovascular Disease 17(22%) 15(19%) NS -Μechanical valve heart 2(2%) 2(2%) NS -Diabetes Mellitus 20(26%) 17(22%) NS -Polycystic Kidney Disease 2(1%) 1(1%) NS Hemoglobin (g/dL) 10.9±1.6 11.1±1.3 NS Creatinine (mg/dL) 2.4±1.1 2.5±1.1 NS eGFR(mL/min/1.73 m2) 35.2±16.9 30.0±13.4 NS B12 (pg/mL) 512.0±369.0 655.0±414.0 NS hs-CRP (mg/L) 3.9±5.9 3.7± 4.9 NS IL-6 (pg/mL) 6.2±5.3 5.78±4.5 NS sTfR (mg/L) 2.27±0.99 1.76±0.76 0.014 Log (1+Hepc25) 0.552±0.343 0.728±0.348 0.027 sTfR/Hepc25 1.91±1.53 0.80±0.72 0.002 Table 2. Sensitivity and specificity of Hepcidin and sTfR/H as predictors of responsiveness to IV FCM AUC 95%C.I. P-value Cut-off Point Sensitivity Specificity Hepc25 0.648 0.52-0.77 0.025 1.49 84% 48% sTfR/Hepc25 0.680 0.56-0.80 0.006 1.21 82% 52% Disclosures No relevant conflicts of interest to declare.
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Delarue, Richard, Herve Tilly, Gilles Andre Salles, Catherine Thieblemont, Serge Bologna, Herve Ghesquieres, Olivier Hermine, Corinne Haioun et Andre Bosly. « Iron Parameters and Relation To Prognosis In Elderly Patients With Aggressive Lymphoma Receiving First Line Immunochemotherapy : An Analysis Of The Lysa LNH 03-6B Study ». Blood 122, no 21 (15 novembre 2013) : 2202. http://dx.doi.org/10.1182/blood.v122.21.2202.2202.
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Abstract Introduction Anemia is a common feature at diagnosis of patients with lymphoid malignancies and has been previously described as an important prognostic factor (Moullet et al. Ann Oncol 1998). Recent guidelines recommend evaluating iron parameters as part of the initial assessment of cancer associated anemia in order to propose iron therapy for patients with functional or absolute iron deficiency. However, incidence of iron parameters abnormalities and impact on prognosis is largely unknown. Methods The phase III randomized LNH 03-6B protocol included elderly patients from 60 to 80-year with untreated diffuse large B-cell lymphoma and an age-adjusted International Prognostic Index (aaIPI) of 1 or more. Patients were randomized between 8 cycles of R-CHOP given every 2 or 3 weeks (Delarue et al. Lancet Oncol 2013) and between a prophylactic treatment with Darbepoetin alfa in order to maintain hemoglobin level between 13 and 14 g/dL versus an usual management of chemotherapy-induced anemia including ESAs and transfusions. Iron parameters including serum iron, transferrin and ferritin levels and transferrin saturation (TSAT) were measured at screening and at the end of study treatment. Iron deficiency was defined by TSAT below 20% and was considered either as true or functional if ferritin level was below or above normal or value, respectively. Results At diagnosis, median serum iron level was 9 µmol/L (n=358 patients, range: 0.14-62.6), median transferrin level was 2.1 g/L (n=262 patients, range: 0.3-29), median ferritin level was 325 ng/mL (n=321 patients, range: 6-6071) and median TSAT was 17% (n=258 patients, range: 2-57). Among patients with available TSAT data, 163/258 (63%) presented a coefficient lower than 20%. When comparing with the whole study population, patients with TSAT ≤ 20% had similar baseline characteristics including aaIPI. In univariate analysis, there is no difference of PFS (HR: 1.078, 95%CI: 0.734-1.584, p=0.7006) and OS (HR: 0.963, 95%CI: 0.622-1.491, p=0.8664) according to TSAT. By contrast, in univariate and multivariate analysis, patients with ferritin level lower than normal and patients with ferritin level higher than normal presented, compared with patients with normal ferritin level, worse PFS (respectively, HR: 4,973, 95%CI: 1.673-14.780, p=0.039; HR: 1,654, 95%CI: 1.094-2.499, p =0,017) and OS (respectively HR: 6.204, 95%CI: 1.713-22.475, p=0.0055; HR: 1.8, 95%CI: 1.108-2.923, p =0.0175). Conclusion Elderly patients with untreated aggressive lymphoma and iron deficiency as measured by TSAT showed similar characteristics compared to the whole population. TSAT level did not impact prognosis in contrast to ferritin level, whose variations could be independent of iron metabolism. The high frequency of iron deficiency at diagnosis raise the question of the use of IV iron as a frontline treatment of chemotherapy-associated anemia. A prospective, placebo-controlled, phase III trial is planned within our group, whose primary objective will be to demonstrate efficacy of ferric carboxymaltose alone compared to placebo as measured by the diminution of percentage of patients requiring red blood cell transfusion and/or ESA administration. Disclosures: No relevant conflicts of interest to declare.
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Kandyliari, Aikaterini, Ioannis-Nektarios Elmaliklis, Olga Kontopoulou, Marianna Tsafkopoulou, Georgios Komninos, Christina Ntzatha, Andreas Petsas, Haralabos C. Karantonis et Antonios E. Koutelidakis. « An Epidemiological Study Report on the Antioxidant and Phenolic Content of Selected Mediterranean Functional Foods, Their Consumption Association with the Body Mass Index, and Consumers Purchasing Behavior in a Sample of Healthy Greek Adults ». Applied Sciences 11, no 17 (25 août 2021) : 7818. http://dx.doi.org/10.3390/app11177818.
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Functional food consumption is shown to have a positive effect on anthropometric parameters and human health promotion. In addition, consumers seem to be more interested in food choices, that may have a positive effect on their health. The current study aimed to identify the antioxidant and phenolic content of naturally functional foods from the Mediterranean diet and to investigate consumer behavior towards their consumption in terms of their weight control, as well as their purchasing behavior and knowledge of functional foods. For this purpose, blueberries, cranberries, pomegranate, grapefruit, red peppers, almonds and mountain tea were analyzed for their phenolic content and antioxidant capacity, using the Folin-Ciocalteau and Ferric Reducing Antioxidant Power assays, respectively. Furthermore, nine hundred forty-nine healthy Greek adults participated in an epidemiological study, by completing a validated food frequency questionnaire, for the consumption of the above investigated functional foods. Five hundred and fifty participants also completed an online questionnaire investigating factors that consumers evaluate when purchasing functional foods. Study results showed that the analyzed functional foods were high in antioxidants and phenolic compounds, especially the mountain tea. The increased consumption of cranberries, pomegranate, grapefruit, red peppers and mountain tea was significantly correlated with a decreased Body Mass Index, suggesting a possible positive role, in weight control. Participants seemed to be aware of the beneficial role of these specific investigated Mediterranean functional foods to human health. They evaluated the price, taste and nutritional value, as critical factors to buy these food products. A combination of factors seems to lead them to purchase and consume these functional foods. Future epidemiological and clinical studies should be conducted in order to further evaluate consumer preferences and bioactivity mechanisms related to Mediterranean functional food consumption.
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Parashar, Rahul, Lachhman Das Singla, Mayank Gupta et Suresh Kumar Sharma. « Evaluation and correlation of oxidative stress and haemato-biochemical observations in horses with natural patent and latent trypanosomosis in Punjab state of India ». Acta Parasitologica 63, no 4 (19 décembre 2018) : 733–43. http://dx.doi.org/10.1515/ap-2018-0087.
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Abstract The haemato-biochemical indices and oxidative stress markers in horses naturally infected with Trypanosoma evansi were evaluated by analyzing the level of these parameters between T. evansi infected (microscopically positive patent group and PCR positive latent group) and infection free horses. To compare the hemato-biochemical indices and oxidative stress indicators, horses were divided into three categories based on diagnostic test employed and positive results obtained. These included Romanowsky stained slide positive group (Group I; n = 6), PCR positive group (group II; n = 28) and negative control group (group III, n = 30), revealing parasitologically positive patent, molecular positive latent and disease free status of horses. A significant reductions in total erythrocytes count (TEC, P = 0.01), haemoglobin (Hb, P = 0.01) and packed cell volume (PCV, P = 0.04) was noticed both in group I and group II while significant neutrophilia and lymphocytopenia was observed in group I when compared to negative control group. Substantial increase in creatinine (CRTN, P = 0.032) and gamma glutamyl transferase (GGT, P = 0.012) in group I while significant decrease in glucose (GLU, P = 0.04) and iron (Fe, P = 0.01) were noticed in both group I and group II in comparison to group III. A significant difference in lipid peroxides (LPO, P = 0.01) with highest level in patent group I (15.33 ± 0.53) followed by PCR positive latent group (14.09 ± 1.66) indicates higher lipid peroxidation in erythrocytes and oxidative stress in decreasing order when compared with infection free control horses (9.83 ± 0.97). Catalase (CAT, P = 0.01) was significantly lower in parasitological (0.82 ± 0.14) and molecular positive cases (1.27 ± 0.35) in comparison to control group (3.43 ± 0.96). The levels of superoxide dismutase (SOD, P = 0.01), reduced glutathione (GSH, P = 0.01) and ferric reducing antioxidant power (FRAP, P = 0.01) were significantly lower in parasito-molecular positive cases as compared to infection free control horses. An inverse correlation of RBC count with LPO and GSH and a direct correlation with catalase, SOD and FRAP was revealed. Overall, the observed substantial decreases in the oxidative parameters like catalase CAT, SOD, GSH and FRAP activities with remarkably elevated levels of LPO indicate high exposure of erythrocytes to oxidative damage in T.evansi infected horses.
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Armstrong, Katherine, Nicki C. Siersch, Tiziana Boffa-Ballaran, Daniel J. Frost, Tony Yu et Yanbin Wang. « Equations of state, phase relations, and oxygen fugacity of the Ru-RuO2 buffer at high pressures and temperatures ». American Mineralogist 105, no 3 (1 mars 2020) : 333–43. http://dx.doi.org/10.2138/am-2020-7060.
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Abstract Experimental studies and measurements of inclusions in diamonds show that ferric iron components are increasingly stabilized with depth in the mantle. To determine the thermodynamic stability of such components, their concentration needs to be measured at known oxygen fugacities. The metal-oxide pair Ru and RuO2 are ideal as an internal oxygen fugacity buffer in high-pressure experiments. Both phases remain solid to high temperatures and react minimally with silicates, only exchanging oxygen. To calculate oxygen fugacities at high pressure and temperature, however, requires information on the phase relations and equation of state properties of the solid phases. We have made in situ synchrotron X-ray diffraction measurements in a multi-anvil press on mixtures of Ru and RuO2 to 19.4 GPa and 1473 K with which we have determined phase relations of the RuO2 phases and derived thermal equations of state (EoS) parameters for both Ru and RuO2. Rutile-structured RuO2 was found to undergo two phase transformations, first at ~7 GPa to an orthorhombic structure and then above 12 GPa to a cubic structure. The phase boundary of the cubic phase was constrained for the first time at high pressure and temperature. We have derived a continuous Gibbs free energy expression for the tetragonal and orthorhombic phases of RuO2 by fitting the second-order phase transition boundary and P-V-T data for both phases, using a model based on Landau theory. The transition between the orthorhombic and cubic phases was then used along with EoS terms derived for both phases to determine a Gibbs free energy expression for the cubic phase. We have used these data to calculate the oxygen fugacity of the Ru + O2 = RuO2 equilibrium, which we have parameterized as a single polynomial across the stability fields of all three phases of RuO2. The expression is log10fO2(Ru – RuO2) = (7.782 – 0.00996P + 0.001932P2 – 3.76 × 10–5P3) + (–13 763 + 592P – 3.955P2)/T + (–1.05 × 106 – 4622P)/T2, which should be valid from room pressure up to 25 GPa and 773–2500 K, with an estimated uncertainty of 0.2 log units. Our calculated fO2 is shown to be up to 1 log unit lower than estimates that use previous expressions or ignore EoS terms.
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Qin, Wei, Beibei Xu et Shenqiang Ren. « An organic approach for nanostructured multiferroics ». Nanoscale 7, no 20 (2015) : 9122–32. http://dx.doi.org/10.1039/c5nr01435b.
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Rajakovic-Ognjanovic, Vladana, et Branimir Grgur. « Corroded scale analysis from water distribution pipes ». Chemical Industry 65, no 5 (2011) : 507–15. http://dx.doi.org/10.2298/hemind110523049r.
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The subject of this study was the steel pipes that are part of Belgrade's drinking water supply network. In order to investigate the mutual effects of corrosion and water quality, the corrosion scales on the pipes were analyzed. The idea was to improve control of corrosion processes and prevent impact of corrosion on water quality degradation. The instrumental methods for corrosion scales characterization used were: scanning electron microscopy (SEM), for the investigation of corrosion scales of the analyzed samples surfaces, X-ray diffraction (XRD), for the analysis of the presence of solid forms inside scales, scanning electron microscopy (SEM), for the microstructural analysis of the corroded scales, and BET adsorption isotherm for the surface area determination. Depending on the composition of water next to the pipe surface, corrosion of iron results in the formation of different compounds and solid phases. The composition and structure of the iron scales in the drinking water distribution pipes depends on the type of the metal and the composition of the aqueous phase. Their formation is probably governed by several factors that include water quality parameters such as pH, alkalinity, buffer intensity, natural organic matter (NOM) concentration, and dissolved oxygen (DO) concentration. Factors such as water flow patterns, seasonal fluctuations in temperature, and microbiological activity as well as water treatment practices such as application of corrosion inhibitors can also influence corrosion scale formation and growth. Therefore, the corrosion scales found in iron and steel pipes are expected to have unique features for each site. Compounds that are found in iron corrosion scales often include goethite, lepidocrocite, magnetite, hematite, ferrous oxide, siderite, ferrous hydroxide, ferric hydroxide, ferrihydrite, calcium carbonate and green rusts. Iron scales have characteristic features that include: corroded floor, porous core that contains both fluid and solid, relatively dense shell-like layer that covers the porous core and provides structural integrity to the scale, and surface layer that is present on top of the shell-like layer at scale-water interface and loosely attached to the shell-like layer. Iron(II) deposits are formed under reducing conditions. The presence of relatively soluble Fe(II) deposits such as siderite and ferrous hydroxide was confirmed by XRD and SEM analysis. In the presence of carbonic species, siderite (FeCO3) is prevailing ferrous deposit. Further studies are needed for obtaining greater knowledge on the mechanism of iron release from corroded pipes and the influence of water quality to iron corrosion.