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دسترسی آزاد مقاله
1 - Fabrication of Au/ZnO/MWCNTs electrode and its characterization for electrochemical cholesterol biosensor
Davood Ghanei Agh Kaariz Elham Darabi Seyed Mohammad ElahiAbstractIn this work, a new sensitive enzyme-based electrode for electrochemical cholesterol biosensor was fabricated based on a nanocomposite of Au nanoparticles, ZnO nanoparticles and multi-wall carbon nanotubes (Au/ZnO/MWCNTs). The nanocomposite was prepared by sol–g چکیده کاملAbstractIn this work, a new sensitive enzyme-based electrode for electrochemical cholesterol biosensor was fabricated based on a nanocomposite of Au nanoparticles, ZnO nanoparticles and multi-wall carbon nanotubes (Au/ZnO/MWCNTs). The nanocomposite was prepared by sol–gel method and deposited on FTO substrate by dip coating, followed by cholesterol oxidase (ChOx) enzyme immobilized (ChOx/Au/ZnO/MWCNTs). Structural properties and morphology of the nanocomposite have been studied using X-ray diffraction (XRD) and Field emission scanning electron microscopy (FESEM). The sample was subjected to Fourier transform infrared spectroscopy (FTIR) to determine functional groups. Electrochemical behavior of the electrode was studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques as a function of cholesterol concentration. Electrochemical impedance spectroscopy (EIS) was also considered to study of surface modified electrodes. The ChOx/Au/ZnO/MWCNTs electrode has been found to have enhanced electron transfer and display excellent analytical linear performances. The fabricated electrode exhibited low detection limit (0.1 μM), high sensitivity (25.89 μA/μM) evaluated from DPV data in the detection range of 0.1–100 µM and high selectivity in the determination of cholesterol over glucose and uric acid. The application of the ChOx/Au/ZnO/MWCNTs electrode in detection of cholesterol in human serum was also confirmed. پرونده مقاله -
دسترسی آزاد مقاله
2 - Nickel Oxide/Carbon Nanotubes as Active Hybrid Material for Oxygen Evolution Reaction
Moein Mohseni Fereshteh Chekin Shahla FathiCarbon nanotubes are of great interest due to their high surface area and rich edge sites, which are favorable for wide applications. Here, a simple and efficient routine is presented by decoration of multi-wall carbon nanotube (MWCNT) with nickel oxide (NiO) nanopartic چکیده کاملCarbon nanotubes are of great interest due to their high surface area and rich edge sites, which are favorable for wide applications. Here, a simple and efficient routine is presented by decoration of multi-wall carbon nanotube (MWCNT) with nickel oxide (NiO) nanoparticles.The morphologies of NiO-MWCNT were investigated by using scanning electron microscope (SEM) and energydispersive X-ray spectroscopy (EDS). In alkaline media, the carbon paste electrode (CPE) modified with NiO-MWCNT catalyses oxygen evolution reaction (OER) with an onset potential of 0.61 V (vs. Ag|AgCl|KCl3M), showing a synergistic effect between MWCNT and NiO nanoparticles. After the long-termI-t measurement, high electrochemical stability confirms the improved electrocatalytic performance of NiO-MWCNT. This study affords us a NiO-MWCNT based electrocatalyst with high performance and strong durability under alkaline conditions, whichcan be applied to energy conversion and storage. پرونده مقاله -
دسترسی آزاد مقاله
3 - Study of the effects of solvent and temperature on the Connections of the MTX and L-FMTX with single-walled carbon nanotubes using QM and MM
Vahid Khodadadi neda hasanzadeh Hoorye Yahyaei Ayeh RaayatzadehIn this study, using the density functional theory (DFT) computational methods and Monte Carlo simulation, the interaction of methotrexate (MTX) and its derivative (L-FMTX) with Single-walled carbon nanotubes (SWCNTS) was investigated. Through the DFT method, the effect چکیده کاملIn this study, using the density functional theory (DFT) computational methods and Monte Carlo simulation, the interaction of methotrexate (MTX) and its derivative (L-FMTX) with Single-walled carbon nanotubes (SWCNTS) was investigated. Through the DFT method, the effects of different solvents (water, methanol, ethanol, dimethyl sulfoxide and dimethylformamide) on the interaction of methotrexate (MTX) and its derivative (L-FMTX) with Single-walled carbon nanotubes within the Onsager self-consistent reaction field (SCRF) model, as well as the effects of temperature on the stability of interactions between compounds in various solvents were studied. Using theoretical calculations, The effects of temperature on the stability of the bond between the compounds and total density of states (DOS) as well as boundary molecular orbitals (FMOS) related to the mentioned compounds were investigated. The molecular properties of compounds such as ionization potential (I), electron affinity (A), chemical hardness (η), electronic chemical potential (µ) and electronegativity (χ) were also used. The interaction resulting from the binding of methotrexate (MTX) to Single-walled carbon nanotubes as well as the interaction of the methotrexate derivative (L-FMTX) with Single-walled carbon nanotubes were studied through molecular mechanics using the Monte Carlo simulation method in the four AMBER, OPLS, CHARMM and MM+ force fields at different temperatures. The results showed that the MTX structure with the SWCNT single wall nanotube was more stable than the L-FMTX structure with SWCNT single wall nanotube. The results showed that the most stable solvent for the above-mentioned structures was water and that the most efficient force field was MM+. پرونده مقاله -
دسترسی آزاد مقاله
4 - On-line Pre-Concentration and Separation of Inorganic Arsenic Based on Nano Platinum-Multiwall Carbon Nanotubes
Hamid Shirkhanloo Ali Akbar Miran Beigi Amir Vahid Nasrin Shirkhanloo Behzad Kalantri Hossein Ali GhadirianOn-line solid phase extraction (SPE) based on nano adsorbent for pre-concentration of inorganic arsenic in water and waste water samples was developed prior to determine by hydride generation atomic absorption spectrometry (HG-AAS). By hydride generation simulation syst چکیده کاملOn-line solid phase extraction (SPE) based on nano adsorbent for pre-concentration of inorganic arsenic in water and waste water samples was developed prior to determine by hydride generation atomic absorption spectrometry (HG-AAS). By hydride generation simulation system (HGSS), the inorganic arsenic in liquid samples changed to hydride form and pass through nano platinum multi wall carbon nanotube (3 wt % Pt, NPt-MWCNT,). The hydride form of arsenic (AsH3), pre-concentrated on NPt-MWCNTs and then completely desorption by electric heater accessory at 200oC for determining. The detection limit (LOD) and linear range of perposed method were obtained 0.4 ng L-1 and 6 –410 ng L-1 respectively(R2 = 0.9988). The relative standard deviations (%RSD) at 100 ng L-1 of analyte were found less than 5%. The capacity and efficiency of nano adsorbent were 75 mg g-1 and 96% at argon flow rate less than 100 ml min-1. The developed method was applied successfully to determination of ultra trace of inorganic arsenic in environmental samples by HG-AAS. پرونده مقاله -
دسترسی آزاد مقاله
5 - Determination of Acetaminophen Via TiO2/MWCNT Modified Electrode
Ali Asghar Pasban Elham Hossein Nia Masoumeh PiryaeiElectrochemical behaviour of acetaminophen at the multi wall carbon nanotubes/titanium dioxide (MWCNT/TiO2) composite film modified glassy carbon electrode (GCE) via solvent casting method was studied. It is shown that the MWCNT/TiO2/GCE exhibits remarkable improvement چکیده کاملElectrochemical behaviour of acetaminophen at the multi wall carbon nanotubes/titanium dioxide (MWCNT/TiO2) composite film modified glassy carbon electrode (GCE) via solvent casting method was studied. It is shown that the MWCNT/TiO2/GCE exhibits remarkable improvement in analytical response as compared to other electrodes. Comparing the responses of the MWCNT/TiO2/GCE with that obtained at the unmodified glassy carbon electrode, the peak currents were enhanced significantly by 8.5 folds (oxidation peak) and 11.0 folds (reduction peak), which showed stable response with enhanced selectivity and sensitivity. A linear calibration plot having a correlation coefficient of 0.991 was obtained in the concentration range of 0.01-0.12 mM acetaminophen. The detection limit for the detection of acetaminophen was calculated as 11.77 μM based on 3 σ/m. The method was applied in the determination of acetaminophen in commercial tablets. The recoveries of the composite modified electrode obtained were 95.2 and 96.2% for five determinations. پرونده مقاله -
دسترسی آزاد مقاله
6 - مطالعه نظری پایداری داروی دارای عامل آلکیلهکننده کلرامبوسیل با نانولولههای کربنی و نانولولههای بور نیتریدی : روشهای مکانیک کوانتومی/مکانیک مولکولی (QM/MM)
محمد حسن جمشیدی ندا حسن زاده حوریه یحیایی امیر بهرامینانولولهها بهعنوان وسیلهای برای کاهش عوارض جانبی داروهای شیمیدرمانی و تسهیل رساندن کارآمدتر دارو به بافتهای هدف عمل میکنند. این مطالعه بر دو نوع نانوحامل تمرکز دارد: نانولولههای کربنی تک جداره و نانولولههای نیترید بور، که هر کدام داروی دارای عامل آلکیلهکننده را چکیده کاملنانولولهها بهعنوان وسیلهای برای کاهش عوارض جانبی داروهای شیمیدرمانی و تسهیل رساندن کارآمدتر دارو به بافتهای هدف عمل میکنند. این مطالعه بر دو نوع نانوحامل تمرکز دارد: نانولولههای کربنی تک جداره و نانولولههای نیترید بور، که هر کدام داروی دارای عامل آلکیلهکننده را حمل میکنند: کلرامبوسیل) این تحقیق به بررسی پایداری این حامل¬ها در دماها و شرایط حلال مختلف می¬پردازد. با استفاده از روشهای محاسبه مکانیک کوانتومی، تعامل بین ترکیبات دارویی ضد سرطان کلرامبوسیل با دو نانو حامل در طیفی از دماها و محیطهای حلالی متفاوت مورد بررسی قرار گرفت. با بررسی پارامترهای ترمودینامیکی از طریق محاسبات مکانیک مولکولی مقادیر مربوط به پارامترهای سختی، قطبیت، انرژی آزاد گیبس و همچنین گپ هومو و لوموی ترکیبات محاسبه شد. همچنین با استفاده از محاسبات مکانیک مولکولی، میدان های نیروی بهینه و کمترین حالت انرژی در هر حلال تعیین شد. یافته¬های این تحقیق نویدبخش توسعه سیستم¬های دارورسانی هدفمند و حفظ این ترکیبات دارویی حیاتی است. پرونده مقاله
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