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Design and fabrication of an electrochemical aptasensor using Au nanoparticles/carbon nanoparticles/cellulose nanofibers nanocomposite for rapid and sensitive detection of Staphylococcus aureus
, Article Bioelectrochemistry ; Volume 123 , 2018 , Pages 70-76 ; 15675394 (ISSN) ; Shahrokhian, S ; Sharif University of Technology
Elsevier B.V
2018
Abstract
Since that pathogenic bacteria are major threats to human health, this paper describes the fabrication of an effective and durable sensing platform based on gold nanoparticles/carbon nanoparticles/cellulose nanofibers nanocomposite (AuNPs/CNPs/CNFs) at the surface of glassy carbon electrode for sensitive and selective detection of Staphylococcus aureus (S. aureus). The AuNPs/CNPs/CNFs nanocomposite with the high surface area, excellent conductivity, and good biocompatibility was used for self-assembled of the thiolated specific S. aureus aptamer as a sensing element. The surface morphology of AuNPs/CNPs/CNFs nanocomposite was characterized with field emission scanning electron microscopy...
Fabrication of modified TiO 2 nanoparticle carbon paste electrode for simultaneous determination of dopamine, uric acid, and l-cysteine
, Article Journal of Solid State Electrochemistry ; Volume 13, Issue 9 , 2009 , Pages 1433-1440 ; 14328488 (ISSN) ; Talebi, A ; Naeimi, H ; Nejati Barzoky, M ; Taghavinia, N ; Sharif University of Technology
2009
Abstract
A carbon paste electrode, modified with 2, 2″-[1,7- hepthandiylbis(nitriloethylidyne)]-bis-hydroquinone and TiO 2 nanoparticles, was used for the simultaneous determination of dopamine (DA), uric acid (UA), and l-cysteine. The study was carried out by using cyclic voltammetry, chronoamperometry, and square wave voltammetry (SWV) techniques. Some kinetic parameters such as the electron transfer coefficient (α) and heterogeneous rate constant (k s) were also determined for the DA oxidation. A dynamic range of 8.0-1400 μM, with the detection limit of 8.4∈×∈10 -7 M for DA, was obtained using SWV (pH∈=∈7.0). The prepared electrode was successfully applied for the determination of DA, UA, and...
Multi-walled carbon nanotubes with immobilised cobalt nanoparticle for modification of glassy carbon electrode: Application to sensitive voltammetric determination of thioridazine
, Article Biosensors and Bioelectronics ; Volume 24, Issue 11 , 2009 , Pages 3235-3241 ; 09565663 (ISSN) ; Ghalkhani, M ; Adeli, M ; Amini, M. K ; Sharif University of Technology
2009
Abstract
Multi-walled carbon nanotubes (MWCNTs) were immobilised with cobalt nanoparticles and analyzed by transmission electron microscopy. This modification procedure substantially improved colloidal dispersion of the immobilised MWCNTs in water and organic solvents, yielding uniform and stable thin films for modification of the glassy carbon electrode surface. The modified electrode showed an efficient catalytic role for the electrochemical oxidation of thioridazine (TR), leading to remarkable decrease in its oxidation overpotential of approximately 100 mV and enhancement of the kinetics of the electrode reaction, which can be confirmed by increasing in the peak current and sharpness of the peak....
Beamforming, null-steering, and simultaneous spatial and frequency domain filtering in integrated phased array systems
, Article AEU - International Journal of Electronics and Communications ; Volume 110 , 2019 ; 14348411 (ISSN) ; Atarodi, S. M ; Sharif University of Technology
Elsevier GmbH
2019
Abstract
In the case that phased array systems are not capable of attenuating interferences, Radio Frequency (RF) front-ends and Analog Digital Converters (ADCs) with a large dynamic range are required to avoid saturation of the receiver. This leads to a higher power consumption. In this paper, employing N-path circuits in Mixer-First receivers, a novel method is introduced in which spatial and frequency blockers are eliminated right before entering the system on the antennas input. In fact using this technique, adjustable spatial notch filter and band-pass frequency filter are implemented to suppress spatial and frequency interferences. The proposed method enhances the robustness and effectiveness...
Amine modified magnetic polystyrene for extraction of drugs from urine samples
, Article Journal of Chromatography A ; Volume 1602 , 2019 , Pages 107-116 ; 00219673 (ISSN) ; Maleki, M ; Bagheri, H ; Sharif University of Technology
Elsevier B.V
2019
Abstract
Polystyrene is one of the best candidates as the extracting medium due to its high stability in different media and acceptable extraction capability. However, the hydrophobic nature and low wettability of polystyrene limits its application to non–polar analytes. To resolve this limitation, in this project, amine groups were chemically attached to the surface of magnetic polystyrene. The resulting hydrophilic magnetic particles were expected to be capable of extracting both polar and non–polar analytes. Non–steroidal anti–inflammatory drugs (NSAIDs) were chosen for testing the applicability of modified magnetic polystyrene according to the importance of their analysis and also their wide...
The geometrical characteristics of nickel-based metal organic framework on its entrapment capability
, Article Journal of Chromatography A ; Volume 1610 , 2020 ; Abbasi, A ; Bagheri, H ; Sharif University of Technology
Elsevier B.V
2020
Abstract
Here, a three dimensional nickel–based metal organic framework (MOF) was synthesized via solvothermal and room temperature protocols. In order to study the effects of the synthesis conditions on the physical properties such as pore sizes and shapes of the prepared MOFs, their extraction capabilities were examined. Both MOFs were characterized by Fourier transform infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy, Brunauer–Emmett–Teller and thermogravimetric analyses. Brilliant properties such as porous structure, high surface area and considerable thermal stability make them reasonable candidates to be employed as efficient extractive phases. The efficiency of the...
Differential pulse voltammetric determination of N-acetylcysteine by the electrocatalytic oxidation at the surface of carbon nanotube-paste electrode modified with cobalt salophen complexes
, Article Sensors and Actuators, B: Chemical ; Volume 133, Issue 2 , 12 August , 2008 , Pages 599-606 ; 09254005 (ISSN) ; Kamalzadeh, Z ; Bezaatpour, A ; Boghaei, D. M ; Sharif University of Technology
2008
Abstract
The preparation and electrochemical performance of the carbon nanotube-paste electrode modified with salophen complexes of cobalt(III) perchlorate, with various substituents on the salophen ligand, as well as their electrocatalytic activity toward the oxidation of N-acetylcysteine (NAC) is investigated. Several Schiff base complexes containing various nucleophilic and electrophilic functional groups were prepared, and their electrochemical characteristics for the electro-oxidation of NAC were evaluated using cyclic and differential pulse voltammetry (CV and DPV). The results revealed, the modified electrodes show an efficient and selective electrocatalytic activity toward the anodic...
Electrocatalytic oxidation and nanomolar determination of guanine at the surface of a molybdenum (VI) complex-TiO2 nanoparticle modified carbon paste electrode
, Article Journal of Electroanalytical Chemistry ; Volume 624, Issue 1-2 , 2008 , Pages 73-78 ; 15726657 (ISSN) ; Taleat, Z ; Beitollahi, H ; Salavati Niasari, M ; Mirjalili, B. B. F ; Taghavinia, N ; Sharif University of Technology
Elsevier
2008
Abstract
A modified carbon paste electrode was prepared by incorporating TiO2 nanoparticles with bis[bis(salicylidene-1,4-phenylenediamine)molybdenum(VI)]. A mixture of fine graphite powder with 4 wt% of TiO2 nanoparticles was applied for the preparation of the carbon paste (by dispersing in paraffin) and finally modified with a molybdenum (VI) complex. The electrocatalytic oxidation of guanine (G) was investigated on the surface of the molybdenum (VI) complex-TiO2 nanoparticle modified carbon paste electrode (MCTNMCPE) using cyclic voltammetry (CV), differential pulse voltammetry (DPV), chronoamperometry (CHA) and chronocoloumetry (CHC). Using the modified electrode, the kinetics of G...
A low-power, second-order Δ/∑ modulator using a single class-AB op-amp for voice-band applications
, Article Analog Integrated Circuits and Signal Processing ; Volume 49, Issue 2 , 2006 , Pages 199-211 ; 09251030 (ISSN) ; Sahandiesfanjani, F ; Heydari, P ; Atarodi, S. M ; Sharif University of Technology
2006
Abstract
The design of a power-efficient second-order Δ/∑ modulator for voice-band is presented. At system level, a new single-loop, single-stage modulator is proposed. The modulator employs only one class-AB op-amp to realize a second-order noise shaping for voice-band applications. The modulator is designed in a 0.25μm standard CMOS process, and exhibits 86 dB dynamic range (DR) for a 4 kHz voice-bandwidth. The proposed modulator consumes 125μW from a 2.5 V supply. © Springer Science + Business Media, LLC 2006
An enhanced dynamic range low-power delta-sigma modulator for portable voice band applications
, Article 2003 Southwest Symposium on Mixed-Signal Design, SSMSD 2003, 23 February 2003 through 25 February 2003 ; 2003 , Pages 263-268 ; 0780377788 (ISBN); 9780780377783 (ISBN) ; Aslanzadeh, H. A ; Mehrmanesh, S ; Vahidfar, M. B ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2003
Abstract
A new second order sigma delta modulator with the reduced number of op-amps, to decrease static power consumption and area, is presented for voice band applications such as codecs. This switched capacitor modulator uses reused capacitor technique to reduce the input thermal noise and circuit area. It improves the DR of modulator by almost 0.5 bit. The modulator shows 87 dB DR for voice band while consuming 125 μW from a 2.5 V supply. © 2003 IEEE
A 1.8V high dynamic range CMOS Gm-c filter for portable video systems
, Article 14th International Conference on Microelectronics, ICM 2002, 11 December 2002 through 13 December 2002 ; Volume 2002-January , 2002 , Pages 38-41 ; 0780375734 (ISBN) ; Aslanzadeh, H. A ; Vahidfar, M. B ; Atarodi, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2002
Abstract
A 4th order, 5 MHz, lowpass Butterworth Gm-c filter has been combined with a low noise low-voltage amplifier to form a lowpass filter for video applications. In this filter an improved transconductor and a powerful method is used to adjust the transconductance gain for tuning application. A continuous variable gain current-to-current converter is used to tune the transconductor value. The THD of the filter is -77 dB for 1 Vppd input signal. Input referred noise is 40 nV/√Hz in the worst case. All the circuits are designed based on a 0.25 μm CMOS process technology with a single 1.8 V supply. © 2002 IEEE
A high dynamic range CMOS variable gain filter for ADSL
, Article 2002 IEEE International Symposium on Circuits and Systems, Phoenix, AZ, 26 May 2002 through 29 May 2002 ; Volume 4 , 2002 , Pages IV/257-IV/260 ; 02714310 (ISSN) ; Atarodi, M ; IEEE ; Sharif University of Technology
2002
Abstract
A 3rd order, 1.1 MHz, lowpass butterworth Gm-c filter has been combined with a low noise Variable Gain Amplifier to form the Variable Gain Filter (VGF). In this VGF an improved transconductor is used and a new method is used to adjust the transconductance gain for tuning application. A continuous variable gain current-to-current converter is used to tune the transconductor value. The THD of the VGF is -85 dB for 1 Vppd input signal and -50 dB for 3 Vppd input signal. VGF gain can be varied from 0 to 31 dB with 1 dB variation steps. Input referred noise is 20 nV/√Hz for maximum gain. All the circuits are designed based on a 0.25 μm CMOS process technology
Direct decoration of carbon nanohorns with binary nickel-cobalt sulfide nanosheets towards non-enzymatic glucose sensing in human fluids
, Article Electrochimica Acta ; Volume 428 , 2022 ; 00134686 (ISSN) ; Hekmat, F ; Wang, H ; Amaratunga, G. A. J ; Unalan, H. E ; Shahrokhian, S ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
A highly controllable, green, and rapid strategy is demonstrated for fabricating of highly sensitive non-enzymatic glucose sensing platforms. Carbon nanohorns (CNHs) were decorated onto the screen-printed electrodes. Binary nickel-cobalt sulfide (NiCo-S) nanosheets (NSs) were then deposited on CNH-casted electrodes by a facile and scalable method. Following detailed structural characterization and the electrocatalytic activity of the fabricated NiCo-S/CNH electrodes towards electro-oxidation of glucose was examined in detail. The proposed electrodes operated within two distinct linear dynamic ranges of 0.001- 0.330 mM and 0.330 - 4.53 mM with sensitivities of 1842 µA.mM−1.cm−2 and 854...
A novel ratiometric fluorescent approach for the modulation of the dynamic range of lateral flow immunoassays
, Article Advanced Materials Technologies ; Volume 7, Issue 8 , 2022 ; 2365709X (ISSN) ; Torné Morató, H ; Parolo, C ; Ranjbar, S ; Farahmand Nejad, M. A ; Álvarez Diduk, R ; Idili, A ; Hormozi Nezhad, M. R ; Merkoçi, A ; Sharif University of Technology
John Wiley and Sons Inc
2022
Abstract
The majority of lateral flow assays (LFAs) use single-color optical labels to provide a qualitative naked-eye detection, however this detection method displays two important limitations. First, the use of a single-color label makes the LFA prone to results misinterpretation. Second, it does not allow the precise modulation of the sensitivity and dynamic range of the test. To overcome these limitations, a ratiometric approach is developed. In particular, using anti-HIgG functionalized red-fluorescent quantum dots on the conjugate pad (as target dependent labels) and blue-fluorescent nanoparticles fixed on the test line (as target independent reporters), it is possible to generate a wide color...
The Analysis of HDR Video Reconstruction Methods
, M.Sc. Thesis Sharif University of Technology ; Amini, Arash (Supervisor)
Abstract
The conventional cameras and displays do not have the ability to record and display the full brightness of the world around us. These deficiencies have led to the development of methods known as High Dynamic Range Imaging. Most of the work done in this field falls into two groups: compression of the light range and its expansion. In compression, the brightness range is intended to display content with a high dynamic range in simple displays. But the goal of expanding the brightness range is to reconstruct HDR content from a low dynamic range one. In addition to the above classification, this field is also categorized based on the type of content (image or video). In this study, the...
HDR Image Reconstruction from a Single-Exposure LDR Image
, M.Sc. Thesis Sharif University of Technology ; Amini, Arash (Supervisor) ; Mohammadzadeh, Nargesolhoda (Co-Supervisor)
Abstract
High dynamic range (HDR) images provide more realistic experience in displaying real-world scenes than conventional low dynamic range (LDR) images by providing much more detailed luminance information; However, most imaging content is still available in low dynamic range. Inverse tonemapping is known as the problem of inferring an HDR image from a single-exposure LDR image in which the lost data caused by saturation of bright parts and quantization must be reconstructed.To address this problem, in this thesis, two fully-automatic architectures based on convolutional neural networks, are proposed. Both these architectures utilize a number of convolutional auto-encoders as...
Design & Implementation of high dynamic range current measurement system for Iot applications
, Article IEEE Transactions on Instrumentation and Measurement ; Volume 71 , 2022 ; 00189456 (ISSN) ; Atarodi, S. M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
Internet-of-Things (IoT) devices have a strict necessity for power consumption to achieve the expected battery life. Therefore, measuring and optimizing the energy consumption of IoT nodes are essential. IoT nodes feature extreme current consumption range over 100 dB between their operating modes. The main focus of this article is to design and implement a low-power and low-cost current measurement circuit, which can be integrated into IoT nodes. A new pass element is introduced for measuring the current consumption. This element is placed in the current path to measure current over a high dynamic range with a constant voltage drop. The introduced pass element consists of a capacitor and...