oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 142 )

2018 ( 287 )

2017 ( 289 )

2016 ( 285 )

Custom range...

Search Results: 1 - 10 of 149731 matches for " Abbastabar Ahangar H "
All listed articles are free for downloading (OA Articles)
Page 1 /149731
Display every page Item
The effect of laser repetition rate on the LASiS synthesis of biocompatible silver nanoparticles in aqueous starch solution
Zamiri R,Zakaria A,Abbastabar Ahangar H,Darroudi M
International Journal of Nanomedicine , 2013,
Abstract: Reza Zamiri,1 Azmi Zakaria,1,* Hossein Abbastabar Ahangar,2 Majid Darroudi,3 Golnoosh Zamiri,1 Zahid Rizwan,1 Gregor PC Drummen4,* 1Department of Physics, Faculty of Science, Universiti Putra Malaysia, Serdang, Selangor, Malaysia; 2Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, Selangor Darul Ehsan, Malaysia; 3Advanced Materials and Nanotechnology Laboratory, Institute of Advanced Technology (ITMA), Universiti Putra Malaysia, Serdang, Selangor, Malaysia; 4Bionanoscience and Bio-Imaging Program, Cellular Stress and Ageing Program, Bio&Nano-Solutions, Düsseldorf, Germany*These authors contributed to this work equallyAbstract: Laser ablation-based nanoparticle synthesis in solution is rapidly becoming popular, particularly for potential biomedical and life science applications. This method promises one pot synthesis and concomitant bio-functionalization, is devoid of toxic chemicals, does not require complicated apparatus, can be combined with natural stabilizers, is directly biocompatible, and has high particle size uniformity. Size control and reduction is generally determined by the laser settings; that the size and size distribution scales with laser fluence is well described. Conversely, the effect of the laser repetition rate on the final nanoparticle product in laser ablation is less well-documented, especially in the presence of stabilizers. Here, the influence of the laser repetition rate during laser ablation synthesis of silver nanoparticles in the presence of starch as a stabilizer was investigated. The increment of the repetition rate does not negatively influence the ablation efficiency, but rather shows increased productivity, causes a red-shift in the plasmon resonance peak of the silver–starch nanoparticles, an increase in mean particle size and size distribution, and a distinct lack of agglomerate formation. Optimal results were achieved at 10 Hz repetition rate, with a mean particle size of ~10 nm and a bandwidth of ~6 nm 'full width at half maximum' (FWHM). Stability measurements showed no significant changes in mean particle size or agglomeration or even flocculation. However, zeta potential measurements showed that optimal double layer charge is achieved at 30 Hz. Consequently, Ag–NP synthesis via the laser ablation synthesis in solution (LASiS) method in starch solution seems to be a trade-off between small size and narrow size distributions and inherent and long-term stability.Keywords: laser ablation, repetition rate, silver nanoparticle, starch, amylose, amylopectin
The effect of laser repetition rate on the LASiS synthesis of biocompatible silver nanoparticles in aqueous starch solution
Zamiri R, Zakaria A, Abbastabar Ahangar H, Darroudi M, Zamiri G, Rizwan Z, Drummen GPC
International Journal of Nanomedicine , 2013, DOI: http://dx.doi.org/10.2147/IJN.S36036
Abstract: t of laser repetition rate on the LASiS synthesis of biocompatible silver nanoparticles in aqueous starch solution Original Research (719) Total Article Views Authors: Zamiri R, Zakaria A, Abbastabar Ahangar H, Darroudi M, Zamiri G, Rizwan Z, Drummen GPC Published Date January 2013 Volume 2013:8 Pages 233 - 244 DOI: http://dx.doi.org/10.2147/IJN.S36036 Received: 17 July 2012 Accepted: 12 September 2012 Published: 11 January 2013 Reza Zamiri,1 Azmi Zakaria,1,* Hossein Abbastabar Ahangar,2 Majid Darroudi,3 Golnoosh Zamiri,1 Zahid Rizwan,1 Gregor PC Drummen4,* 1Department of Physics, Faculty of Science, Universiti Putra Malaysia, Serdang, Selangor, Malaysia; 2Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, Selangor Darul Ehsan, Malaysia; 3Advanced Materials and Nanotechnology Laboratory, Institute of Advanced Technology (ITMA), Universiti Putra Malaysia, Serdang, Selangor, Malaysia; 4Bionanoscience and Bio-Imaging Program, Cellular Stress and Ageing Program, Bio&Nano-Solutions, Düsseldorf, Germany *These authors contributed to this work equally Abstract: Laser ablation-based nanoparticle synthesis in solution is rapidly becoming popular, particularly for potential biomedical and life science applications. This method promises one pot synthesis and concomitant bio-functionalization, is devoid of toxic chemicals, does not require complicated apparatus, can be combined with natural stabilizers, is directly biocompatible, and has high particle size uniformity. Size control and reduction is generally determined by the laser settings; that the size and size distribution scales with laser fluence is well described. Conversely, the effect of the laser repetition rate on the final nanoparticle product in laser ablation is less well-documented, especially in the presence of stabilizers. Here, the influence of the laser repetition rate during laser ablation synthesis of silver nanoparticles in the presence of starch as a stabilizer was investigated. The increment of the repetition rate does not negatively influence the ablation efficiency, but rather shows increased productivity, causes a red-shift in the plasmon resonance peak of the silver–starch nanoparticles, an increase in mean particle size and size distribution, and a distinct lack of agglomerate formation. Optimal results were achieved at 10 Hz repetition rate, with a mean particle size of ~10 nm and a bandwidth of ~6 nm 'full width at half maximum' (FWHM). Stability measurements showed no significant changes in mean particle size or agglomeration or even flocculation. However, zeta potential measurements showed that optimal double layer charge is achieved at 30 Hz. Consequently, Ag–NP synthesis via the laser ablation synthesis in solution (LASiS) method in starch solution seems to be a trade-off between small size and narrow size distributions and inherent and long-term stability.
Simple Synthesis and Characterization of Cobalt Ferrite Nanoparticles by a Thermal Treatment Method
Mahmoud Goodarz Naseri,Elias B. Saion,Hossein Abbastabar Ahangar,Abdul Halim Shaari,Mansor Hashim
Journal of Nanomaterials , 2010, DOI: 10.1155/2010/907686
Abstract: Crystalline, magnetic, cobalt ferrite nanoparticles were synthesized from an aqueous solution containing metal nitrates and polyvinyl pyrrolidone (PVP) as a capping agent by a thermal treatment followed by calcination at various temperatures from 673 to 923?K. The structural characteristics of the calcined samples were determined by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and transmission electron microscopy (TEM). A completed crystallization occurred at 823 and 923?K, as shown by the absence of organic absorption bands in the FT-IR spectrum. Magnetization measurements were obtained at room temperature by using a vibrating sample magnetometer (VSM), which showed that the calcined samples exhibited typical magnetic behaviors. 1. Introduction The spinel ferrite structure with the formula of MFe2O4 (M = Co, Ni, Zn, or other metals) can be described as a cubic, closely packed arrangement of oxygen atoms, and M2+ and Fe3+ ions can occupy either tetrahedral (A) or octahedral (B) sites [1]. Spinel ferrite nanoparticles have attracted much attention because of their electronic, magnetic, and catalytic properties, all of which are different from those of their bulk counterparts. Among spinel ferrites, cobalt ferrite (CoFe2O4) has an inverse spinel structure in which, in the ideal state, all Co2+ ions are in B sites, and Fe3+ ions are equally distributed between A and B sites. Cobalt ferrite has been widely studied due to its high electromagnetic performance, excellent chemical stability, mechanical hardness, high coercivity, and moderate saturation magnetization, which make it a good candidate for the electronic components used in computers, recording devices, and magnetic cards [2–4]. These properties are dependent on chemical composition and microstructural characteristics, which can be controlled in the fabrication and synthesis processes. In order to acquire materials with the desired physical and chemical properties, the preparation of cobalt ferrite nanoparticles through different routes has become an important area of research and development. Various methods of synthesizing spinel cobalt ferrite nanoparticles have been reported, such as ball milling [5], a ceramic method by firing [5], coprecipitation [5–7], reverse micelles [8], hydrothermal methods [9, 10], a polymeric precursor [11], sol-gel [12], microemulsions [13], laser ablation [14], a polyol method [15], sonochemical approaches [16], and aerosol method [17]. Various precipitation agents have been used to prepare cobalt ferrite nanoparticles of a specific size
Fabrication of Silver Nanoparticles Dispersed in Palm Oil Using Laser Ablation
Reza Zamiri,Azmi Zakaria,Hossein Abbastabar Ahangar,Amir Reza Sadrolhosseini,Mohd Adzir Mahdi
International Journal of Molecular Sciences , 2010, DOI: 10.3390/ijms11114764
Abstract: In this study we used a laser ablation technique for preparation of silver nanoparticles. The fabrication process was carried out by ablation of a silver plate immersed in palm oil. A pulsed Nd:YAG laser at a wavelength of 1064 nm was used for ablation of the plate at different times. The palm oil allowed formation of nanoparticles with very small and uniform particle size, which are dispersed very homogeneously within the solution. The obtained particle sizes for 15 and 30 minute ablation times were 2.5 and 2?nm, respectively. Stability study shows that all of the samples remained stable for a reasonable period of time.
Complex Matter Space and Relativistic Quantum Mechanics  [PDF]
Reza Ahangar
Applied Mathematics (AM) , 2014, DOI: 10.4236/am.2014.521317
Abstract: The Special Relativity Theory cannot recognize speed faster than light. New assumption will be imposed that matter has two intrinsic components, 1) mass, and 2) charge, that is M = m + iq. The mass will be measured by real number system and charged by an imaginary unit. This article presents a Complex Matter Space in Relativistic Quantum Mechanics. We are hoping that this approach will help us to present a general view of energy and momentum in Complex Matter Space. The conclusion of this article on Complex Matter Space (CMS) theory will lead help to a better understanding toward the conversion of mass and energy equation, unifying the forces, and unifying relativity and quantum mechanics.
The Relativistic Geometry of the Complex Matter Space  [PDF]
Reza Ahangar
Journal of Applied Mathematics and Physics (JAMP) , 2017, DOI: 10.4236/jamp.2017.52037
Abstract: Duality behavior of photons in wave-particle property has posed challenges and opportunities to discover other frontiers of fundamental particles leading to the relativistic and quantum description of matter. The speed of particles faster than the speed of light could not be recognized, and matter was always described as a real number. A new fundamental view on matter as a complex value has been introduced by many authors who present a paradigm that is shifted from real or pure imaginary particles to Complex Matter Space. A new assumption will be imposed that matter has two intrinsic components: i) mass, and ii) charge. The mass will be measured by real number systems and charged by an imaginary unit. The relativistic concept of Complex Matter Space on energy and momentum is investigated and we can conclude that the new Complex Matter Space (CMS) theory will help get one step closer to a better understanding toward: 1) Un-Euclidean description of Minkowski Geometry in the context of the Complex Matter Space, 2) transformation from Euclidean to Minkowski space and its relativistic interpretation. Finally, geometrical foundations are essential to have a real picture of space, matter, and the universe.
Variation of Parameters for Causal Operator Differential Equations  [PDF]
Reza R. Ahangar
Applied Mathematics (AM) , 2017, DOI: 10.4236/am.2017.812134
Abstract:
The operator T from a domain D into the space of measurable functions is called a nonanticipating (causal) operator if the past information is independent from the future outputs. We will study the solution x(t) of a nonlinear operator differential equation where its changes depends on the causal operator T, and semigroup of operator A(t), and all initial parameters (t0, x0) . The initial information is described x(t)=φ(t) for almost all tt0 and φ(t0) =φ0. We will study the nonlinear variation of parameters (NVP) for this type of nonanticipating operator differential equations and develop Alekseev type of NVP.
Comparison of the cytotoxic effects of Juniperus sabina and Zataria multiflora extracts with Taxus baccata extract and Cisplatin on normal and cancer cell lines
Shokrzadeh M,Azadbakht M,Ahangar N,Naderi H
Pharmacognosy Magazine , 2010,
Abstract: Isolation and identification of some potent anti-tumor compounds from medicinal plants has motivated researchers to screen different parts of plant species for the determination of anti-tumor effects. In this study, cytotoxic effects and IC 50 of specific concentrations of hydro-alcoholic extracts of fruits of Juniperus sabina and leaves of Zataria multiflora were compared with hydro-alcoholic extract of bark of Taxus baccata and Cisplatin, well-known anticancer compounds, on normal (CHO and rat fibroblast) and cancer (HepG2 and SKOV3) cell lines. The hydro-alcoholic extracts of the plants were prepared by percolation. The cytotoxic effects and IC 50 of the extracts on the cell lines were studied followed by colonogenic assay after 72 h incubation. The results showed that the extract of Juniperus sabina possesses lower IC 50 in comparison with Zataria multiflora extract on all 4 normal and cancer cell lines (P < 0.05); but, IC 50 of the Juniperus sabina extract was significantly higher than the Taxus baccata extract and Cisplatin on all 4 normal and cancer cell lines (P < 0.05). As a result, it is concluded that the extract of J. sabina has almost similar cytotoxicity with the extract of Taxus baccata on cancer cells.
Some extensions of Enestr?m-Kakeya Theorem
N. A. Rather,Suhail Gulzar,S. H. Ahangar
Mathematics , 2015,
Abstract: In this paper we obtain some refinements of a well-known result of Enestr\"o-Kakeya concerning the bounds for the moduli of the zeros of polynomials with complex coefficients which improve upon some results due to Aziz and Mohammad, Govil and Rahman and others.
On the polar derivative of a polynomial
N. A. Rather,S. H. Ahangar,Suhail Gulzar
Mathematics , 2014,
Abstract: Let $P(z)$ be a polynomial of degree $n$ having no zero in $|z|
Page 1 /149731
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.