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dna-damage
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Investigation of Ocular Tumor Dose Enhancement in Proton Therapy in the Presence of Nanoparticles of Different Materials
, M.Sc. Thesis Sharif University of Technology ; Hosseini, Abolfazl (Supervisor) ; Salimi, Ehsan (Supervisor)
Abstract
In recent years, the effect of the presence of nanoparticles in the tumor in order to increase the benefit of the treatment in radiation therapy has been the focus of many researchers. Although for photon irradiation, a significant dose increase due to the presence of nanoparticles has been observed, in the case of proton irradiation, due to the different nature of the beam and the lower cross-section of protons with metals compared to photons, scattered and in some cases contradictory findings have been published in the articles, and more studies are needed in this field. Due to laboratory limitations, Monte Carlo simulation is an appropriate tool for simulating difficult real-world...
Design of amino acid- and carbohydrate-based anticancer drugs to inhibit polymerase η
, Article Scientific Reports ; Volume 12, Issue 1 , 2022 ; 20452322 (ISSN) ; Fattahi, A ; Sharif University of Technology
Nature Research
2022
Abstract
DNA polymerase η (polη) is of significant value for designing new families of anticancer drugs. This protein takes a role in many stages of the cell cycle, including DNA replication, translesion DNA synthesis, and the repairing process of DNA. According to many studies, a high level of expression of polη in most cases has been associated with low rates of patients' survival, regardless of considering the stage of tumor cells. Thus, the design of new drugs with fewer side effects to inhibit polη in cancerous cells has attracted attention in recent years. This project aims to design and explore the alternative inhibitors for polη, which are based on carbohydrates and amino acids. In terms of...
Exact Simulation of Varian Clinac 2100C/D with Use of Phase Space file and Representation of Appropriate Source Model for Clinical Applications
, Ph.D. Dissertation Sharif University of Technology ; Sohrabpour, Mostafa (Supervisor) ; Rabi Mahdavi, Saeed (Co-Advisor)
Abstract
MC Simulation is considered to be one of the most accurate methods for transport of radiation in various media. Computational speed is the limiting factor to apply the MC method in clinical settings. One of the methods to increase the speed in MC simulations is the use of phase space file (PSF). PSF is generated by transporting the particles through the linear accelerator head. The characteristics of these particles crossing a reference plane are stored in the PSF file. The PSF can be used in subsequent simulations as a radiation source. The use of PSF is effective but has a drawback of having latent variance. Latent variance is a problem inherent in using phase space files. Latent variance...
Cytotoxicity and cell cycle effects of bare and poly(vinyl alcohol)-coated iron oxide nanoparticles in mouse fibroblasts
, Article Advanced Engineering Materials ; Volume 11, Issue 12 , 2009 , Pages B243-B250 ; 14381656 (ISSN) ; Simchi, A ; Vali, H ; Imani, M ; Shokrgozar, M. A ; Azadmanesh, K ; Azari, F ; Sharif University of Technology
Abstract
Super-paramagnetic iron oxide nanoparticles (SPIONs) are recognized as powerful biocompatible materials for use in various biomedical applications, such as drug delivery, magnetic-resonance imaging, cell/protein separation, hyperthermia and transfection. This study investigates the impact of high concentrations of SPIONs on cytotoxicity and cell-cycle effects. The interactions of surfacesaturated (via interactions with cell medium) bare SPIONs and those coated with poly(vinyl alcohol) (PVA) with adhesive mouse fibroblast cells (L929) are investigated using an MTT assay. The two SPION formulations are synthesized using a co-precipitation method. The bare and coated magnetic nanoparticles with...
Synthesis and cyto-genotoxicity evaluation of graphene on mice spermatogonial stem cells
, Article Colloids and Surfaces B: Biointerfaces ; Volume 146 , 2016 , Pages 770-776 ; 09277765 (ISSN) ; Akhavan, O ; Shamsara, M ; Daliri, M ; Dashtizad, M ; Farmany, A ; Sharif University of Technology
Elsevier
2016
Abstract
The present study analyzed the dose-dependent cyto- and genotoxicity of graphene oxide and reduced graphene oxide on spermatogonial stem cells (SSCs) for the first time. The results showed that graphene oxide significantly increased oxidative stress at concentrations of 100 and 400 μg/ml, while low concentrations did not have a significant effect. In addition, according to the MTT assay, the cell number decreased in high-concentration (100 and 400 μg/ml) graphene oxide-treated samples compared to untreated cells. However, a reduced graphene-treated sample demonstrated a significant increase in cell number. Moreover, microscopic analysis found high concentrations of graphene nanosheets in...
Cytotoxicity of uncoated and polyvinyl alcohol coated superparamagnetic iron oxide nanoparticles
, Article Journal of Physical Chemistry C ; Volume 113, Issue 22 , 2009 , Pages 9573-9580 ; 19327447 (ISSN) ; Simchi, A ; Imani, M ; Sharif University of Technology
2009
Abstract
Superparamagnetic iron oxide nanoparticles (SPION) are being increasingly used in various biomedical applications such as hyperthermia, cell and protein separation, enhancing resolution of magnetic resonance imaging, and drug delivery. However, the toxicity data for SPION are limited. In this study, uncoated and single polyvinyl alcohol coated SPION with high chemical reactivity (due to the bigger surface area) were synthesized using a coprecipitation method. Cytotoxicity of these magnetic nanoparticles and their ability to cause arrest in cell life-cycles was investigated. Interaction of these nanoparticles with adhesive mouse fibroblast cell line (L929) was probed using MTT assay. High...
The effect of energy spectrum change on DNA damage in and out of field in 10-MV clinical photon beams
, Article Medical and Biological Engineering and Computing ; Volume 53, Issue 1 , January , 2015 , Pages 67-75 ; 01400118 (ISSN) ; Xiao, Y ; Sohrabpour, M ; Studenski, M. T ; Sharif University of Technology
Springer Verlag
2015
Abstract
The aim of this study was to quantify the DNA damage induced in a clinical megavoltage photon beam at various depths in and out of the field. MCNPX was used to simulate 10 × 10 and 20 × 20 cm2 10-MV photon beams from a clinical linear accelerator. Photon and electron spectra were collected in a water phantom at depths of 2.5, 12.5 and 22.5 cm on the central axis and at off-axis points out to 10 cm. These spectra were used as an input to a validated microdosimetric Monte Carlo code, MCDS, to calculate the RBE of induced DSB in DNA at points in and out of the primary radiation field at three depths. There was an observable difference in the energy spectra for photons and electrons for points...