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Efficient geometry of surface plasmon resonance based fiber optic sensor
, Article 2018 IEEE 38th International Conference on Electronics and Nanotechnology, ELNANO 2018 - Proceedings, 24 April 2018 through 26 April 2018 ; 2018 , Pages 351-354 ; 9781538663837 (ISBN) ; Ahmadi, M ; Mohammadpour, R ; Sasanpour, P ; Sharif University of Technology
Abstract
The efficient structure for optical fiber based surface Plasmon resonance sensor has been investigated. The sensor structure is based on removing the cladding of a multimode optical fiber and replacing it with thin film of gold. The incident light inside the fiber will excite surface plasmons which will be resulted in the absorption in specific wavelengths. The absorption behavior is dependent on the dielectric constants at the vicinity of the metallic thin film. Based on the amount of removed cladding and deposition regions on the core structure of the fiber, different configurations can be considered. Based on the computational analysis, we have studied performance of sensor for three...
Gold-Decorated 3D 2,6-diaminopyridine network: a robust catalyst for the bromination of aromatic compounds
, Article Industrial and Engineering Chemistry Research ; Volume 57, Issue 37 , 2018 , Pages 12314-12322 ; 08885885 (ISSN) ; Keshavarzi, N ; Hosseini, S. H ; Matloubi Moghaddam, F ; Sharif University of Technology
American Chemical Society
2018
Abstract
This article reports the synthesis of a magnetic heterogeneous catalyst through the decoration of gold ions onto the cross-linked polymeric nanocomposite from 2,6-diaminopyridine. The activity of the resulting catalyst was then evaluated in the bromination of aromatic compounds. The nitrogen rich support showed a high affinity to gold ions, and the measured content of Au was 0.76 mmol g-1. The structure of the catalyst was fully characterized by using Fourier-transform infrared spectroscopy, thermogravimetric analysis, atomic absorption spectroscopy, transmission electron microscopy, scanning electron microscope, energy-dispersive X-ray spectroscopy, Brunauer-Emmett-Teller surface area...
Label-free detection of β-amyloid peptides (Aβ40 and Aβ42): a colorimetric sensor array for plasma monitoring of alzheimer's disease
, Article Nanoscale ; Volume 10, Issue 14 , 2018 , Pages 6361-6368 ; 20403364 (ISSN) ; Hormozi Nezhad, M. R ; Mahmoudi, M ; Sharif University of Technology
Royal Society of Chemistry
2018
Abstract
Monitoring the ratio of 40- and 42-residue amyloid β peptides (i.e., Aβ40 and Aβ42) in human plasma is considered one of the hallmarks of detection of the early stage of Alzheimer's disease (AD). Therefore, development of a specific, yet non-antibody-based method for simultaneous detection of Aβ40 and Aβ42 may have considerable clinical applications. Here, we developed a 'nanoparticle-based colorimetric sensor array' utilizing label-free gold and silver nanoparticles for visual detection of Aβ42 and Aβ40. Different aggregation behaviors of nanoparticles through their conjugation with Aβ42 and Aβ40 followed by the coordination of Aβ42 and Aβ40 with Cu(ii) led to diverse spectral and color...
A facile approach for reducing the working voltage of Au/TiO2/Au nanostructured memristors by enhancing the local electric field
, Article Nanotechnology ; Volume 29, Issue 1 , 2018 ; 09574484 (ISSN) ; Ebrahimi, M ; Bagheri Shouraki, S ; Moshfegh, A. Z ; Sharif University of Technology
Institute of Physics Publishing
2018
Abstract
Memristor devices have attracted tremendous interest due to different applications ranging from nonvolatile data storage to neuromorphic computing units. Exploring the role of surface roughness of the bottom electrode (BE)/active layer interface provides useful guidelines for the optimization of the memristor switching performance. This study focuses on the effect of surface roughness of the BE electrode on the switching characteristics of Au/TiO2/Au three-layer memristor devices. An optimized wet-etching treatment condition was found to modify the surface roughness of the Au BE where the measurement results indicate that the roughness of the Au BE is affected by both duration time and...
Recurrent poisson factorization for temporal recommendation
, Article IEEE Transactions on Knowledge and Data Engineering ; 2018 ; 10414347 (ISSN) ; Khodadadi, A ; Alizadeh, K ; Arabzadeh, A ; Farajtabar, M ; Zha, H ; Rabiee, H. R. R ; Sharif University of Technology
IEEE Computer Society
2018
Abstract
Poisson Factorization (PF) is the gold standard framework for recommendation systems with implicit feedback whose variants show state-of-the-art performance on real-world recommendation tasks. However, most of the previous work do not explicitly take into account the temporal behavior of users which is essential to recommend the right item to the right user at the right time. In this paper, we introduce a Recurrent Poisson Factorization (RPF) framework that generalizes the classical PF methods by utilizing a Poisson process for modeling the implicit feedback. RPF treats time as a natural constituent of the model, and takes important factors for recommendation into consideration to provide a...
An ultrasensitive label free human papilloma virus DNA biosensor using gold nanotubes based on nanoporous polycarbonate in electrical alignment
, Article Analytica Chimica Acta ; 2018 ; 00032670 (ISSN) ; Ghorbani, M ; Sasanpour, P ; Karimizefreh, A ; Sharif University of Technology
Elsevier B.V
2018
Abstract
An impedimetric human papilloma virus (HPV) DNA biosensor based on gold nanotubes (AuNTs) in label free detection was materialized. The AuNTs decorated nanoporous polycarbonate (AuNTs-PC) template as biosensor electrode was fabricated by electrodeposition method. The single strand DNA (ss-DNA) probe was covalently immobilized onto the AuNTs-PC electrode. The hybridization of target sequences with the ss-DNA probe was observed by the electrochemical impedance spectroscopy (EIS). The biosensor showed high selectivity and could differentiate between the complementary, mismatch and non-complementary DNA sequences. The EIS measurements were matched to Randle's equivalent circuit. The...
ZnO nanowires from nanopillars: influence of growth time
, Article Current Nanoscience ; Volume 5, Issue 4 , 2009 , Pages 479-484 ; 15734137 (ISSN) ; Roozbehi, M ; Akhavan, O ; Moshfegh, A. R ; Sharif University of Technology
2009
Abstract
A double-tube vapor phase transport system has been used to grow ZnO nanostructures. Nanopillars, nanorods and nanowires of zinc oxide were synthesized on Au nanoparticle catalyst depending on source-substrate distance and temperature gradient in the quartz tube. In addition, influence of growth time and substrate temperature on the morphology of the nanorods and nanowires were also investigated. The scanning electron microscope (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM) were employed to further understand the nanostructures growth mechanism on various temperatures and growth time steps. Longer length (>4μm) with hexagonal-cross-sectional nanowires, in [002]...
Stability and size-dependency of cauchy-born hypothesis in three-dimensional applications
, Article International Journal of Solids and Structures ; Volume 46, Issue 9 , 2009 , Pages 1925-1936 ; 00207683 (ISSN) ; Abdolhosseini Qomi, M. J ; Kazemi, M. T ; Khoei, A. R ; Sharif University of Technology
2009
Abstract
The Cauchy-Born hypothesis (CB) provides a hierarchical approach in the molecular theory of crystal elasticity to relate the continuum and atomic deformations. This kinematic theory has been extensively used as the constitutive law of continuum regions in multi-scale models. In these models, the fine scale is proposed to describe the real behavior of crystalline structure wherever the continuum description fails. The main objective of this article is to investigate the stability and size-dependency of CB hypothesis in three-dimensional applications by direct comparison of information between atomistic and continuous description of a medium. The Sutton-Chen many-body potential is used for the...
Improvement of planar perovskite solar cells by using solution processed SnO2/CdS as electron transport layer
, Article Solar Energy ; Volume 191 , 2019 , Pages 647-653 ; 0038092X (ISSN) ; Javadpour, S ; Taghavinia, N ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
The efficiency of planar perovskite solar cells (PSCs) with SnO2 as electron transport layer is already more than 19% achieved under controlled atmosphere. PSCs with solution processed SnO2 show high hysteresis and low fill factor. One way to improve the planar PSCs is using buffer layer between electron transport layer and perovskite to enhance the photo-electron extraction process. In this study, SnO2 and SnO2/CdS layers were fabricated by solution process using a suspension including CdS nanoparticles synthesized via a simple solution route. Then planar PSCs with the structure of Glass/FTO/ETL/Perovskite/Sprio-OMeTAD/Au were fabricated in ambient air condition using SnO2 and SnO2/CdS as...
Pt-M (M = Au and Tl) Dative Bonds Using Bis(cyclometalated)platinum(II) Complexes
, Article Organometallics ; Volume 38, Issue 8 , 2019 , Pages 1709-1720 ; 02767333 (ISSN) ; Jamali, S ; Naseri, S ; Jamjah, A ; Kia, R ; Samouei, H ; Mastrorilli, P ; Shahsavari, H. R ; Raithby, P. R ; Sharif University of Technology
American Chemical Society
2019
Abstract
Symmetrical and unsymmetrical biscyclometalated platinum(II) complexes [Pt(ptpy)2], 1, and [Pt(ptpy)(bppy)], 2, in which ptpy = deprotonated 2-(p-tolyl)pyridine and bppy = deprotonated 2-(3-bromophenyl)pyridine, have been prepared from the reaction between tris(pentafluorophenyl)borane, B(C6F5)3 and 1 equiv of monocyclometalated complexes [PtMe(ptpy)(ptpyH)], B, and [PtMe(ptpy)(bppyH)], C, respectively. The solid-state structures of 1 and 2 have been determined by X-ray crystallography. The reaction of 1 with 1 equiv of TlPF6 or [Au(PPh3)]OTF resulted in the production of heteronuclear complexes [Pt(ptpy)2Tl]PF6, 3 and {Pt(ptpy)2[Au(PPh3)]}OTF, 4, respectively. X-ray diffraction data showed...
Recurrent poisson factorization for temporal recommendation
, Article IEEE Transactions on Knowledge and Data Engineering ; Volume 32, Issue 1 , 2020 , Pages 121-134 ; Khodadadi, A ; Alizadeh, K ; Arabzadeh, A ; Farajtabar, M ; Zha, H ; Rabiee, H. R ; Sharif University of Technology
IEEE Computer Society
2020
Abstract
Poisson Factorization (PF) is the gold standard framework for recommendation systems with implicit feedback whose variants show state-of-the-art performance on real-world recommendation tasks. However, they do not explicitly take into account the temporal behavior of users which is essential to recommend the right item to the right user at the right time. In this paper, we introduce Recurrent Poisson Factorization (RPF) framework that generalizes the classical PF methods by utilizing a Poisson process for modeling the implicit feedback. RPF treats time as a natural constituent of the model, and takes important factors for recommendation into consideration to provide a rich family of...
Synthesis of micelles based on chitosan functionalized with gold nanorods as a light sensitive drug delivery vehicle
, Article International Journal of Biological Macromolecules ; Volume 149 , 2020 , Pages 809-818 ; Bagherifard, M ; Doroudian, M ; Sharif University of Technology
Elsevier B.V
2020
Abstract
This study aims to design photo-triggered micelles by using a natural base polymer. Chitosan was functionalized with thiourea, and in the next step, it was modified by grafting poly(L-lactide), poly(N-isopropylacrylamide), and poly(acrylamide) in determined ratio to form thermo-sensitive micelles. The sulfur content of chitosan@thiourea was measured about 2%. Grafting of polymers on chitosan was characterized by FT-IR and NMR techniques. The critical micellar concentration was measured by using photo luminescence spectroscopy. The size and surface morphology experiments revealed that average size of micelles is about 14 nm, and the length and width of GNRs are about 65 and 19 nm,...
Protein corona impact on nanoparticle-cell interactions: Toward an energy-based model of endocytosis
, Article Journal of Physics Condensed Matter ; Volume 32, Issue 11 , 2020 ; Mehrafrooz, B ; Montazeri, A ; Naghdabadi, R ; Sharif University of Technology
Institute of Physics Publishing
2020
Abstract
Upon incubation of nanoparticles in biological fluids, a new layer called the protein corona is formed on their surface affecting the interactions between nanoparticles and targeted cells during the endocytosis process. In the present study, a mathematical model based on the diffusion of membrane mobile receptors is proposed. Opposing the endocytosis proceeding, membrane bending and tension energies are named as resistant energy. Also, the binding energy and free-energy associated with the configurational entropy are collectively termed promoter energy. Utilizing this model, endocytosis of gold nanoparticle (GNP) is simulated to explore the biological media effect. The results reveal that...
Surface plasmon resonance of two-segmented Au-Cu nanorods
, Article Nanotechnology ; Volume 19, Issue 41 , 2008 ; 09574484 (ISSN) ; Iraji Zad, A ; Dolati, A ; Ghorbani, M ; Sharif University of Technology
2008
Abstract
Two-segmented gold-copper nanorods were electrodeposited inside the pores of polycarbonate track-etched membranes from two separate solutions. The PCT membranes were dissolved in dichloromethane (CH2Cl2) and the solvent was replaced by methanol solution. Optical absorption spectra of two-segmented Au-Cu nanorods dispersed in methanol showed two peaks which were related to the transverse mode of copper and the longitudinal mode of gold. By increasing the length of the gold segment, when the total length of both metals was fixed at 1 μm, the copper and gold peaks shifted to the blue and red wavelengths, respectively. We observed that the wavelengths of the extinction peaks are not in good...
Nanotechnology-assisted microfluidic systems: From bench to bedside
, Article Nanomedicine ; Volume 16, Issue 3 , 2021 , Pages 237-258 ; 17435889 (ISSN) ; Ahmadi, S ; Fatahi, Y ; Rabiee, M ; Bagherzadeh, M ; Dinarvand, R ; Bagheri, B ; Zarrintaj, P ; Saeb, M. R ; Webster, T. J ; Sharif University of Technology
Future Medicine Ltd
2021
Abstract
With significant advancements in research technologies, and an increasing global population, microfluidic and nanofluidic systems (such as point-of-care, lab-on-a-chip, organ-on-a-chip, etc) have started to revolutionize medicine. Devices that combine micron and nanotechnologies have increased sensitivity, precision and versatility for numerous medical applications. However, while there has been extensive research on microfluidic and nanofluidic systems, very few have experienced wide-spread commercialization which is puzzling and deserves our collective attention. For the above reasons, in this article, we review research advances that combine micro and nanotechnologies to create the next...
Gold nanoparticles loaded into niosomes: A novel approach for enhanced antitumor activity against human ovarian cancer
, Article Advanced Powder Technology ; Volume 32, Issue 12 , 2021 , Pages 4711-4722 ; 09218831 (ISSN) ; Ferdowsian, S ; Hajrasouliha, S ; Kazempoor, R ; Mirzaie, A ; Sedigh Dakkali, M ; Akbarzadeh, I ; Mohammadmahdi Meybodi, S ; Mirghafouri, M ; Sharif University of Technology
Elsevier B.V
2021
Abstract
In the current study, gold nanoparticles (AuNPs) were prepared using the green synthesis method using Artemisia annua extract, loaded into niosomes, and investigated their cytotoxicity and apoptotic effects. To optimize the niosomal formulation containing AuNPs, the effects of surfactants: cholesterol molar ratio, Span 60: Tween 60 M ratio, and AuNP concentration (µg/mL) were investigated. After examining the drug release profile, mathematical models were assessed to predict release kinetic. The cytotoxicity of noisome encapsulated AuNPs and free AuNPs was evaluated against human ovarian cancer cell line (A2780) by MTT assay. The apoptotic/necrosis ratio was studied using flow cytometry as...
Role of BCP layer on nonlinear properties of perovskite solar cell
, Article Solar Energy ; Volume 213 , 2021 , Pages 383-391 ; 0038092X (ISSN) ; Milani Moghaddam, H ; Bahari, A ; Mohammadpour, R ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Organic-inorganic hybrid halide perovskite materials have been most attractive for wide range of optoelectronic applications. Investigating the photo-response in these devices will be very useful to understanding cell performance in different conditions and applications. For understanding non-linearity photo-response we use the Bathocuproine (BCP) as blocking layer in two interfaces of inverted perovskite solar cell (FTO/NiO/BCP/Perovskite/PCBM/Au and FTO/NiO/Perovskite/PCBM/BCP/Au). Employing thick BCP layer (≈15 nm) caused s-shaped JV curve due to charge accumulation at interfaces. The nonlinearity effect was also explored for devices with s-shaped JV and established that device parameters...
A smart tri-layered nanofibrous hydrogel thin film with controlled release of dual drugs for chemo-thermal therapy of breast cancer
, Article Journal of Drug Delivery Science and Technology ; Volume 76 , 2022 ; 17732247 (ISSN) ; Mohammadi Ziarani, G ; Badiei, A ; Pourjavadi, A ; Kiani, M ; Sharif University of Technology
Editions de Sante
2022
Abstract
A tri-layered nanofibrous hydrogel thin film with temperature sensitivity is introduced as a new controlled drug release system to treat breast cancer. A simultaneous heat generation with the tunable release of dual drugs is observed in response to visible light radiation. A tri-layered nanofibrous sheet was fabricated through sequential electrospinning the blends of Au@Chit@DOX-loaded poly(N-isopropylacrylamide-co-N-methylol acrylamide) (poly (NIPAAm-co-NMA)) and Curcumin-loaded poly (vinyl alcohol) (Cu-loaded PVA), where the Cu-loaded PVA nanofibers (NFs) are sandwiched between two layers of Au@Chit@DOX-loaded poly (NIPAAm-co-NMA) NFs. After thermal crosslinking of the tri-layered...
Plasmon-induced near-infrared fluorescence enhancement of single-walled carbon nanotubes
, Article Carbon ; Volume 194 , 2022 , Pages 162-175 ; 00086223 (ISSN) ; Tsoulos, T. V ; Sajjadi, S. H ; Antonucci, A ; Wu, S. J ; Tagliabue, G ; Fatmehsari Haghshenas, D ; Boghossian, A. A ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Single-walled carbon nanotubes (SWCNTs) emit near-infrared (NIR) fluorescence that is ideal for optical sensing. However, the low quantum yields diminish the sensor's signal-to-noise ratio and limits the penetration depths for in vivo measurements. In this study, we perform a systematic investigation of the plasmonic effects of Ag and Au nanoparticles of various geometries to tune and even enhance the fluorescence intensity of single-stranded DNA-wrapped SWCNTs (ssDNA-SWCNTs). We observe a chirality-dependent NIR fluorescence enhancement that varies with both nanoparticle shape and material, with Au nanorods increasing (7, 5) and (7, 6) chirality emissions by 80% and 60% and Ag nanotriangles...
Catechin mediated green synthesis of Au nanoparticles: Experimental and theoretical approaches to the determination HOMO-LUMO energy gap and reactivity indexes for the (+)-epicatechin (2S, 3S)
, Article Arabian Journal of Chemistry ; Volume 15, Issue 5 , 2022 ; 18785352 (ISSN) ; Khayatkashani, M ; Soltani, N ; Yousif, Q. A ; Salavati Niasari, M ; Sharif University of Technology
Elsevier B.V
2022
Abstract
This work suggests a green method for synthesizing Au nanoparticles (AuNPs) using the aqueous extract of Salix aegyptiaca extract. The mechanism of green synthesized AuNPs was examined by molecular electrostatic potential (MEP) calculations. AuNPs were characterized with different techniques such as Ultraviolet–visible spectroscopy (UV–vis), Fourier-transform infrared spectroscopy (FT-IR) spectroscopy, X-ray diffraction (XRD), and Transmission electron microscopy (TEM). Electrochemical investigation of modified glassy carbon electrode using AuNPs (AuNPs/GCE) shows that the electronic transmission rate between the modified electrode and [Fe (CN)6]3−/4− increased. Process of oxidation, energy...