Graduate University of Advanced Technology

About: Graduate University of Advanced Technology is a education organization based out in Kerman, Iran. It is known for research contribution in the topics: Carbon paste electrode & Electrochemical gas sensor. The organization has 890 authors who have published 2169 publications receiving 31027 citations.

Voltammetric determination of vitamin B 6 (pyridoxine) at a graphite screen-printed electrode modified with graphene oxide/Fe 3 O 4 @SiO 2 nanocomposite

Abstract: The preparation and study of electrochemical properties of a graphite screen-printed electrode (SPE) modified with the GO/Fe3O4@SiO2 (GO is graphene oxide) nanocomposites are described. The morphologies of the GO/Fe3O4@SiO2 nanocomposites were examined by scanning electron microscopy. The electrochemical oxidation of vitamin B6 (pyridoxine) on SPE modified with the GO/Fe3O4@SiO2 nanocomposite was investigated by cyclic voltammetry, differential pulse voltammetry, and chronoamperometry. Under optimum conditions (pH 7.0), the vitamin B6 oxidation at the surface of the modified SPE occurs at a potential about 190 mV less positive than that at the unmodified SPE. A linear voltammetric response for vitamin B6 was obtained in the concentration range 1.0•10 6—9.0•10 4 mol L–1 with a detection limit of 5.2•10 7 mol L–1 using differential pulse voltammetry. The developed sensor was also successfully applied for determination of trace level of vitamin B6 in both the standard vitamin B6 sample and biological samples (urine).

La3+-doped Co3O4 Nanoflowers Modified Graphite Screen Printed Electrode for Electrochemical Sensing of Vitamin B6

Abstract: In this study, we combined the advantages of good conductivity, small size, and large surface area and the catalytic property of La3+/Co3O4 nanoflowers to fabricate an electrochemical sensor sensitive to determination of vitamin B6 in real samples. La3+/Co3O4 nanoflowers were synthesized by a co-precipitation method which is a convenient, environment-friendly, inexpensive process. The synthesized nanoflowers were characterized by SEM. A simple and sensitive sensor based on graphite screen printed electrode (GSPE) modified by La3+/Co3O4 nanoflowers was developed for the electrochemical determination of vitamin B6. The electrochemical behavior of vitamin B6 was studied in 0.1 M phosphate buffer solution (PBS) using cyclic voltammetry (CV), chronoamperometry (CHA) and differential pulse voltammetry (DPV). The modified electrode (La3+/Co3O4NFs/GSPE) showed excellent electrocatalytic activity and remarkable sensitivity towards the oxidation of vitamin B6. The fabricated sensor displayed good operating characteristics including low detection limit, and a wide linear dynamic range for the detection of vitamin B6. Using La3+/Co3O4NFs/GSPE as the working electrode, a linear dynamic range between 1.0 to 600.0 μM and a limit of detection of 0.4 µM were obtained. Finally, reliability and accuracy of the proposed sensor were studied in real samples.

New SRAM design using body bias technique for low-power and high-speed applications

Abstract: In this paper, a new SRAM cell with body-bias actively controlled by a control circuit and word line is introduced to realize low-power and high-speed applications. The cell uses two word lines, which vary between positive and negative voltage levels to control the body bias of cell's transistors. In this design, using a peripheral control circuit with the least possible number of transistors, the access time is decreased and also a trade-off between static and dynamic power consumption is provided. Compared to a conventional SRAM cell, the proposed cell reduces the static power consumption by 82% and improves the read performance by 40% and the write performance by 27%. Copyright © 2013 John Wiley & Sons, Ltd.

Photocatalytic degradation of methylene blue from aqueous solution using Fe3O4@SiO2@CeO2 core-shell magnetic nanostructure as an effective catalyst

Abstract: In the present study, the core-shell magnetic nanostructure of Fe3O4@SiO2@CeO2 was synthesized to investigate its use as an effective photocatalyst for methylene blue removal. The prepared samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and a vibrating sample magnetometer (VSM). The photocatalytic activity for the Fe3O4@SiO2@CeO2 core-shell magnetic nanostructure was investigated under visible light by determining the degradation rate of methylene blue for 50 min. At the end of the photocatalytic degradation process, the magnetic catalyst was recovered by an external magnetic field. The performance of the proposed catalyst for the degradation of methylene blue was improved with the optimization of the effective parameters such as the amount of catalyst, pH, and reaction time. Under optimum conditions, the efficiency of methylene blue removal with the proposed photocatalyst remains higher than 92 % after five times of use. The second pseudo-model was selected as the kinetic model to calculate catalytic degradation. The present results show that the Fe3O4@SiO2@CeO2 can be an efficient nanocatalyst for the photodegradation of dye pollutants.

Calcium and L-histidine effects on ascorbate-glutathione cycle components under nickel-induced oxidative stress in tomato plants

Abstract: The effects of NiSO4, calcium, and L-histidine (His) on the components of ascorbate-glutathione cycle, antioxidant enzymes and lipid peroxidation in a tomato cultivar Early Urbana Y was investigated. The activities of enzymes including catalase (CAT), guaiacol peroxidase (GPX), ascorbate peroxidase (APX), superoxide dismutase (SOD), glutathione reductase (GR), lipoxygenase (LOX), and phenylalanine ammonia lyase (PAL) were measured. In addition, the content of H2O2, ascorbate (ASC), dehydroascorbate (DHA), reduced glutathione (GSH), chlorophyll (Chl) a+b, carotenoids, proteins, malondialdehyde (MDA), membrane aldehydes, and electrolyte leakage (EL) were determined. Results suggest that the excess of Ni increased the content of H2O2, MDA, membrane aldehydes and proteins in roots as well as GPX, LOX, APX activities, and EL in leaves, whereas Ca and His ameliorated these effects. Moreover, decreasing leaf GSH and DHA content and GR activity were observed under the Ni stress, but these parameters were raised by Ca plus His treatment. However, no improvement in leaf protein, ASC, root GSH content, and activities of PAL and CAT were observed by using Ca or His under Ni stress.