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Asadi A, Daneshfar A, Maleki B, Aiken CA. Effects of attentional focus and gaze instruction during observational learning of a basketball free-throw. Hum Mov Sci 2023; 87:103038. [PMID: 36435171 DOI: 10.1016/j.humov.2022.103038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Revised: 11/08/2022] [Accepted: 11/10/2022] [Indexed: 11/24/2022]
Abstract
Observational learning has long been used to instruct individuals on how to perform a novice motor skill. Recently, research has shown a benefit to instructing learners to focus externally when viewing a video model (Asadi, Aiken, Heidari, & Kochackpour, 2021). Research has also highlighted the effectiveness of modeling correct gaze behaviors when learning a cognitive task (Jarodzka, van Gog, Dorr, Scheiter, & Gerjets, 2013). The purpose of the present study was to investigate the effectiveness of combining these two modalities. 40 individuals with a mean age of 21.77 ± 1.40 performed a novel motor task where they were asked to either focus internally or externally, and were provided with traditional instruction or were provided with an experienced performer's gaze behaviors while viewing a video demonstration. It was observed that both the external focus groups and the gaze instructed groups performed a basketball free-throw more accurately and had longer periods of quiet eye than an internal focus or traditional verbal instruction (p's < 0.05). Eye tracking also allowed for the assessment of attentional focus adherence. Participants focused on the instructed cues significantly more than irrelevant task aspects or a different focus types (p's < 0.05). These results highlight the effectiveness of cuing a learner to focus externally during observational learning. It also highlights the usefulness of providing correct gaze behaviors when observing a model.
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Affiliation(s)
- A Asadi
- Department of Motor Behavior, Faculty of Sport Sciences, Alzahra University, Tehran, Iran
| | - A Daneshfar
- Department of Motor Behavior, Faculty of Sport Sciences, Alzahra University, Tehran, Iran.
| | - B Maleki
- Department of Physical Education and Sport Science, Yadegar-e-Imam Khomeini (RAH) Shahre-rey Branch, Islamic Azad University, Tehran, Iran
| | - C A Aiken
- Department of Kinesiology, New Mexico State University, Las Cruces, NM, USA
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Ansari N, Shojaei M, Rostami R, Daneshfar A, Rothwell J. The Effect Of rTMS On Visual Short Term And Spatial Recognition Memory Of Female Elite Volleyball Players Of Iran. Brain Stimul 2015. [DOI: 10.1016/j.brs.2015.01.066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Khezeli T, Daneshfar A. Dispersive micro-solid-phase extraction of dopamine, epinephrine and norepinephrine from biological samples based on green deep eutectic solvents and Fe3O4@MIL-100 (Fe) core–shell nanoparticles grafted with pyrocatechol. RSC Adv 2015. [DOI: 10.1039/c5ra08058d] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
DA, EP and NE were determined without interference of ascorbic acid using grafted Fe3O4@MIL-100 (Fe) NPs and a green solvent.
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Affiliation(s)
- T. Khezeli
- Department of Chemistry
- Faculty of Science
- Ilam University
- Ilam
- Iran
| | - A. Daneshfar
- Department of Chemistry
- Faculty of Science
- Ilam University
- Ilam
- Iran
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Ghaedi M, Nasab AG, Khodadoust S, Sahraei R, Daneshfar A. Characterization of zinc oxide nanorods loaded on activated carbon as cheap and efficient adsorbent for removal of methylene blue. J IND ENG CHEM 2015. [DOI: 10.1016/j.jiec.2014.05.006] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Roosta M, Ghaedi M, Daneshfar A, Darafarin S, Sahraei R, Purkait MK. Simultaneous ultrasound-assisted removal of sunset yellow and erythrosine by ZnS:Ni nanoparticles loaded on activated carbon: optimization by central composite design. Ultrason Sonochem 2014; 21:1441-50. [PMID: 24486199 DOI: 10.1016/j.ultsonch.2014.01.018] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2013] [Revised: 01/12/2014] [Accepted: 01/13/2014] [Indexed: 05/22/2023]
Abstract
The present study focused on the simultaneous ultrasound-assisted removal of sunset yellow and erythrosine dyes from aqueous solutions using ZnS:Ni nanoparticles loaded on activated carbon (ZnS:Ni-NP-AC) as an adsorbent. ZnS:Ni nanoparticles were synthesized and characterized using different techniques such as FESEM, XRD and TEM. The effects of various parameters such as sonication time, pH, initial dye concentrations and adsorbent dose on the percentage of dye removal were investigated. Parameters were optimized by central composite design (CCD) combined with response surface methodology (RSM) and desirability function (DF). A good agreement between experimental and predicted values was observed. The ultrasound-assisted adsorbent (0.04 g) was capable of high percentage removal (98.7% and 99.6%) of sunset yellow and erythrosine in short time (3.8 min).
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Affiliation(s)
- M Roosta
- Chemistry Department, Yasouj University, Yasouj 75918-74831, Iran
| | - M Ghaedi
- Chemistry Department, Yasouj University, Yasouj 75918-74831, Iran.
| | - A Daneshfar
- Department of Chemistry, University of Ilam, P.O. Box 65315-516, Ilam, Iran
| | - S Darafarin
- Department of Chemistry, University of Ilam, P.O. Box 65315-516, Ilam, Iran
| | - R Sahraei
- Department of Chemistry, University of Ilam, P.O. Box 65315-516, Ilam, Iran
| | - M K Purkait
- Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
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Ghaedi M, Ghaedi A, Abdi F, Roosta M, Sahraei R, Daneshfar A. Principal component analysis-artificial neural network and genetic algorithm optimization for removal of reactive orange 12 by copper sulfide nanoparticles-activated carbon. J IND ENG CHEM 2014. [DOI: 10.1016/j.jiec.2013.06.008] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Ghaedi M, Pakniat M, Mahmoudi Z, Hajati S, Sahraei R, Daneshfar A. Synthesis of nickel sulfide nanoparticles loaded on activated carbon as a novel adsorbent for the competitive removal of Methylene blue and Safranin-O. Spectrochim Acta A Mol Biomol Spectrosc 2014; 123:402-409. [PMID: 24412794 DOI: 10.1016/j.saa.2013.12.083] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 12/03/2013] [Accepted: 12/11/2013] [Indexed: 06/03/2023]
Abstract
Nickel sulfide nanoparticle-loaded activated carbon (NiS-NP-AC) were synthesized as a novel adsorbent for simultaneous and rapid adsorption of Methylene blue (MB) and Safranin-O (SO), as most together compounds in wastewater. NiS-NP-AC was characterized using different techniques such as UV-visible, Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and Brunauer-Emmett-Teller (BET). The surface area of the adsorbent was found to be very high (1018m(2)/g according BET). By using central composite design (CCD), the effects of variables such as pH, adsorbent dosage, MB concentration, SO concentration and contact time on binary dyes removal were examined and optimized values were found to be 8.1, 0.022g, 17.8mg/L, and 5mg/L and 5.46min, respectively. The very short time required for the dyes removal makes this novel adsorbent as a promising tool for wastewater treatment applications. Different models were applied to analyze experimental isotherm data. Modified-extended Langmuir model showed good fit to equilibrium data with maximum adsorption capacity at 0.022g of adsorbent. An empirical extension of competitive modified-extended Langmuir model was proposed to predict the simultaneous adsorption behavior of MB and SO. Kinetic models were applied to fit the experimental data at various adsorbent dosages and initial dyes concentrations. It was seen that pseudo-second-order equation is suitable to fit the experimental data. Individual removalof each dye was also studied.
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Affiliation(s)
- M Ghaedi
- Chemistry Department, Yasouj University, Yasouj 75918-74831, Iran.
| | - M Pakniat
- Chemistry Department, Faculty of Science, Persian Gulf University, Bushehr, Iran
| | - Z Mahmoudi
- Chemistry Department, Faculty of Science, Persian Gulf University, Bushehr, Iran
| | - S Hajati
- Department of Physics, Yasouj University, Yasouj 75918-74831, Iran.
| | - R Sahraei
- Chemistry Department, Ilam University, Ilam, Iran
| | - A Daneshfar
- Chemistry Department, Ilam University, Ilam, Iran
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Roosta M, Ghaedi M, Daneshfar A, Sahraei R. Experimental design based response surface methodology optimization of ultrasonic assisted adsorption of safaranin O by tin sulfide nanoparticle loaded on activated carbon. Spectrochim Acta A Mol Biomol Spectrosc 2014; 122:223-31. [PMID: 24326258 DOI: 10.1016/j.saa.2013.10.116] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2013] [Revised: 10/21/2013] [Accepted: 10/31/2013] [Indexed: 05/06/2023]
Abstract
In this research, the adsorption rate of safranine O (SO) onto tin sulfide nanoparticle loaded on activated carbon (SnS-NPAC) was accelerated by the ultrasound. SnS-NP-AC was characterized by different techniques such as SEM, XRD and UV-Vis measurements. The present results confirm that the ultrasound assisted adsorption method has remarkable ability to improve the adsorption efficiency. The influence of parameters such as the sonication time, adsorbent dosage, pH and initial SO concentration was examined and evaluated by central composite design (CCD) combined with response surface methodology (RSM) and desirability function (DF). Conducting adsorption experiments at optimal conditions set as 4 min of sonication time, 0.024 g of adsorbent, pH 7 and 18 mg L(-1) SO make admit to achieve high removal percentage (98%) and high adsorption capacity (50.25 mg g(-)(1)). A good agreement between experimental and predicted data in this study was observed. The experimental equilibrium data fitting to Langmuir, Freundlich, Tempkin and Dubinin-Radushkevich models show that the Langmuir model is a good and suitable model for evaluation and the actual behavior of adsorption. Kinetic evaluation of experimental data showed that the adsorption processes followed well pseudo-second-order and intraparticle diffusion models.
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Affiliation(s)
- M Roosta
- Chemistry Department, Yasouj University, Yasouj 75918-74831, Iran
| | - M Ghaedi
- Chemistry Department, Yasouj University, Yasouj 75918-74831, Iran.
| | - A Daneshfar
- Department of Chemistry, University of Ilam, P.O. Box 65315-516, Ilam, Iran
| | - R Sahraei
- Department of Chemistry, University of Ilam, P.O. Box 65315-516, Ilam, Iran
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Roosta M, Ghaedi M, Shokri N, Daneshfar A, Sahraei R, Asghari A. Optimization of the combined ultrasonic assisted/adsorption method for the removal of malachite green by gold nanoparticles loaded on activated carbon: experimental design. Spectrochim Acta A Mol Biomol Spectrosc 2014; 118:55-65. [PMID: 24041530 DOI: 10.1016/j.saa.2013.08.082] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2013] [Revised: 08/11/2013] [Accepted: 08/15/2013] [Indexed: 05/24/2023]
Abstract
The present study was aimed to experimental design optimization applied to removal of malachite green (MG) from aqueous solution by ultrasound-assisted removal onto the gold nanoparticles loaded on activated carbon (Au-NP-AC). This nanomaterial was characterized using different techniques such as FESEM, TEM, BET, and UV-vis measurements. The effects of variables such as pH, initial dye concentration, adsorbent dosage (g), temperature and sonication time on MG removal were studied using central composite design (CCD) and the optimum experimental conditions were found with desirability function (DF) combined response surface methodology (RSM). Fitting the experimental equilibrium data to various isotherm models such as Langmuir, Freundlich, Tempkin and Dubinin-Radushkevich models show the suitability and applicability of the Langmuir model. Kinetic models such as pseudo -first order, pseudo-second order, Elovich and intraparticle diffusion models applicability was tested for experimental data and the second-order equation and intraparticle diffusion models control the kinetic of the adsorption process. The small amount of proposed adsorbent (0.015 g) is applicable for successful removal of MG (RE>99%) in short time (4.4 min) with high adsorption capacity (140-172 mg g(-1)).
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Affiliation(s)
- M Roosta
- Chemistry Department, Yasouj University, Yasouj 75918-74831, Iran
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Roosta M, Ghaedi M, Daneshfar A, Sahraei R, Asghari A. Optimization of the ultrasonic assisted removal of methylene blue by gold nanoparticles loaded on activated carbon using experimental design methodology. Ultrason Sonochem 2014; 21:242-52. [PMID: 23856588 DOI: 10.1016/j.ultsonch.2013.05.014] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Revised: 05/07/2013] [Accepted: 05/23/2013] [Indexed: 05/07/2023]
Abstract
The present study was focused on the removal of methylene blue (MB) from aqueous solution by ultrasound-assisted adsorption onto the gold nanoparticles loaded on activated carbon (Au-NP-AC). This nanomaterial was characterized using different techniques such as SEM, XRD, and BET. The effects of variables such as pH, initial dye concentration, adsorbent dosage (g), temperature and sonication time (min) on MB removal were studied and using central composite design (CCD) and the optimum experimental conditions were found with desirability function (DF) combined response surface methodology (RSM). Fitting the experimental equilibrium data to various isotherm models such as Langmuir, Freundlich, Tempkin and Dubinin-Radushkevich models show the suitability and applicability of the Langmuir model. Analysis of experimental adsorption data to various kinetic models such as pseudo-first and second order, Elovich and intraparticle diffusion models show the applicability of the second-order equation model. The small amount of proposed adsorbent (0.01 g) is applicable for successful removal of MB (RE>95%) in short time (1.6 min) with high adsorption capacity (104-185 mg g(-1)).
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Affiliation(s)
- M Roosta
- Chemistry Department, Yasouj University, Yasouj 75918-74831, Iran
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Ghaedi M, Taghavimoghadam N, Naderi S, Sahraei R, Daneshfar A. Comparison of removal of bromothymol blue from aqueous solution by multiwalled carbon nanotube and Zn(OH)2 nanoparticles loaded on activated carbon: A thermodynamic study. J IND ENG CHEM 2013. [DOI: 10.1016/j.jiec.2013.01.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Ghaedi M, Pebdani AA, Sadeghian B, Sahraei R, Daneshfar A, Duran C. SYNTHESIS AND CHARACTERIZATION OF CADMIUM SULFIDE NANOPARTICLE–LOADED ACTIVATED CARBON AS A NOVEL ADSORBENT FOR EFFICIENT REMOVAL OF REACTIVE ORANGE 12. CHEM ENG COMMUN 2013. [DOI: 10.1080/00986445.2012.737875] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Ghaedi M, Hekmati Jah A, Khodadoust S, Sahraei R, Daneshfar A, Mihandoost A, Purkait MK. Cadmium telluride nanoparticles loaded on activated carbon as adsorbent for removal of sunset yellow. Spectrochim Acta A Mol Biomol Spectrosc 2012; 90:22-27. [PMID: 22306446 DOI: 10.1016/j.saa.2011.12.064] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2011] [Revised: 12/11/2011] [Accepted: 12/21/2011] [Indexed: 05/31/2023]
Abstract
Adsorption is a promising technique for decolorization of effluents of textile dyeing industries but its application is limited due to requirement of high amounts of adsorbent required. The objective of this study was to assess the potential of cadmium telluride nanoparticles loaded onto activated carbon (CdTN-AC) for the removal of sunset yellow (SY) dye from aqueous solution. Adsorption studies were conducted in a batch mode varying solution pH, contact time, initial dye concentration, CdTN-AC dose, and temperature. In order to investigate the efficiency of SY adsorption on CdTN-AC, pseudo-first-order, pseudo-second-order, Elovich, and intra-particle diffusion kinetic models were studied. It was observed that the pseudo-second-order kinetic model fits better than other kinetic models with good correlation coefficient. Equilibrium data were fitted to the Langmuir model. Thermodynamic parameters such as enthalpy, entropy, activation energy, and sticking probability were also calculated. It was found that the sorption of SY onto CdTN-AC was spontaneous and endothermic in nature. The proposed adsorbent is applicable for SY removal from waste of real effluents including pea-shooter, orange drink and jelly banana with efficiency more than 97%.
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Affiliation(s)
- M Ghaedi
- Chemistry Department, Yasouj University, Yasouj, Iran.
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Ghaedi M, Amirabad SZ, Marahel F, Nasiri Kokhdan S, Sahraei R, Nosrati M, Daneshfar A. Synthesis and characterization of cadmium selenide nanoparticles loaded on activated carbon and its efficient application for removal of muroxide from aqueous solution. Spectrochim Acta A Mol Biomol Spectrosc 2011; 83:46-51. [PMID: 21903452 DOI: 10.1016/j.saa.2011.07.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Revised: 06/21/2011] [Accepted: 07/03/2011] [Indexed: 05/31/2023]
Abstract
In the first, Cadmium selenide Nanoparticle loaded on activated carbon (CdSe-NP-AC) has been synthesized and characterized by different techniques including XRD and SEM. Then, this new adsorbent successfully has been applied for the removal of muroxide (MO) from aqueous solution in batch studies, while the effect of various experimental parameters like initial pH (pH(0)), contact time, amount of (CdSe-NP-AC) and initial MO concentration (C(0)) on its removal percentage was examined by one at a time optimization method. It was found following optimization of variable, the adsorption of MO onto (CdSe-NP-AC) followed pseudo-second-order kinetics and show Tempkin and Langmuir models for interpretation of experimental data. It was observed that by increasing the temperature the removal percentage was improved and the positive change in entropy (ΔS°) and heat of adsorption (ΔH°) show the endothermic nature of process, while the high negative value in Gibbs free energy change (ΔG°) indicates the feasible nature of adsorption process.
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Affiliation(s)
- M Ghaedi
- Chemistry Department Yasouj University, Yasouj, Iran.
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Daneshfar A, Lotfi HJ, Khezeli T. Determination of nalidixic acid using dispersive liquid-liquid microextraction followed by HPLC-UV. ACTA CHROMATOGR 2011. [DOI: 10.1556/achrom.23.2011.4.3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Daneshfar A, Ghaziaskar H, Shiri L, Manafi M, Nikorazm M, Abassi S. Synthesis of 2-ethylhexyl-2-ethylhexanoate catalyzed by immobilized lipase in n-hexane: A kinetic study. Biochem Eng J 2007. [DOI: 10.1016/j.bej.2007.05.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Ghaedi M, Daneshfar A, Shokrollahi A, Ghaedi H, Arvin Pili F. Highly Selective and Sensitive Spectrophotometric Determination of Trace Amounts of Silver Ion in Surfactant Media Using 2-Mercaptobenzoxazole. ACTA ACUST UNITED AC 2007; 97:971-82. [DOI: 10.1002/adic.200790081] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abbasi S, Esfandyarpour M, Taher MA, Daneshfar A. Catalytic-kinetic determination of trace amount of formaldehyde by the spectrophotometric method with a bromate-Janus green system. Spectrochim Acta A Mol Biomol Spectrosc 2007; 67:578-81. [PMID: 16987702 DOI: 10.1016/j.saa.2006.06.046] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2006] [Accepted: 06/24/2006] [Indexed: 05/11/2023]
Abstract
A new simple and rapid catalytic kinetic method for the determination of trace amount of formaldehyde is described. The method is based on the catalytic effect of formaldehyde on the oxidation of Janus green by bromate in the present of sulfuric acid. The reaction monitored spectrophotometrically by measuring the decrease in absorbance of the reaction mixture at 618 nm. The fixed-time method was used for the first 150 s. For initiation of the reaction, under the optimum conditions, in the concentration range of 0.003-2.5 microg ml(-1) formaldehyde can be determined with a limit of detection 0.0015 microg ml(-1). The relative standard deviation of five replicate measurements is 2.3% for 1.0 microg ml(-1) of formaldehyde. The method was used for the determination of formaldehyde in real samples with satisfactory results.
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Affiliation(s)
- S Abbasi
- Department of Chemistry, Ilam University, Ilam, Iran.
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Romero MD, Calvo L, Alba C, Daneshfar A. A kinetic study of isoamyl acetate synthesis by immobilized lipase-catalyzed acetylation in n-hexane. J Biotechnol 2007; 127:269-77. [PMID: 16959353 DOI: 10.1016/j.jbiotec.2006.07.009] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2005] [Revised: 03/30/2006] [Accepted: 07/04/2006] [Indexed: 11/22/2022]
Abstract
The objective of this work was to propose a reaction mechanism and to develop a rate equation for the synthesis of isoamyl acetate by acylation of the corresponding alcohol with acetic anhydride using the lipase Novozym 435 in n-hexane. The reaction between isoamyl alcohol and acetic anhydride occurred at high rate in first place. Then, if excess alcohol was used, produced acetic acid further reacted with remaining alcohol, leading to yields higher than 100% (based on initial acetic anhydride content). This reaction was much slower and took place only when acetic anhydride had been totally consumed. Optimal pH for Novozym 435 was 7.7. Acetic acid strongly inactivated the enzyme but it was partially caused by the pH drop in the biocatalyst aqueous microenvironment. Acetic anhydride also showed an important inhibition effect. On the contrary, isoamyl alcohol and isoamyl acetate had no negative effect on the lipase. The analysis of the initial rate data showed that reaction followed a Ping-Pong Bi-Bi mechanism with inhibition by acetic anhydride. The kinetic constants were obtained by multiple regression analysis of experimental findings. Equation predictions and experimental reaction rate values matched very well at conditions where acetic acid concentration in the medium was low.
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Affiliation(s)
- M D Romero
- Departamento de Ingeniería Química, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid, Spain
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Romero M, Calvo L, Alba C, Daneshfar A, Ghaziaskar H. Enzymatic synthesis of isoamyl acetate with immobilized Candida antarctica lipase in n-hexane. Enzyme Microb Technol 2005. [DOI: 10.1016/j.enzmictec.2004.12.033] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Ghaziaskar HS, Daneshfar A. Solubility of 2-ethyl-hexyl-2-ethyl hexanoate in binary and quaternary systems in supercritical carbon dioxide. J Supercrit Fluids 2003. [DOI: 10.1016/s0896-8446(02)00083-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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