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abootorabi-zarchi--dawood
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Power System State Estimation Including PMUs and Traditional Measurement Instruments
, M.Sc. Thesis Sharif University of Technology ; Hosseini, Hamid (Supervisor)
Abstract
State estimation is a process in which values of unknown system state variables is obtained by considering measurements in such a system. State estimators’ output data are applied in control centers of power systems. Nowadays, using of phasor measurement unit (PMU) in WAMS (Wide Area Measurement Systems) and SCADA have significantly extended. PMUs increase the accuracy proportion compared with traditional measurement units, improve the power networks observability as well as detect and correct bad data. Since the possibility of removing the traditional measurement devices and replacing them with full PMU ones does not exist in the near future it is mandatory to find out an efficient and...
Prognostic Biomarker Selection for Breast Cancer using Bioinformatics and Deep Learning
, M.Sc. Thesis Sharif University of Technology ; Sharifi Zarchi, Ali (Supervisor)
Abstract
Triple Negative Breast Cancer (TNBC) is an invasive subtype of breast cancer. Finding prognostic biomarkers is helpful in choosing the appropriate treatment procedure for patients of this cancer. In recent years, the role of microRNAs in various biological processes, including cancer, has been identified, and their accessibility and stability have made these types of molecules an ideal biomarker. In the first phase of this study, with the aim of overcoming the limitations of previous studies, a new bioinformatics protocol has been proposed to investigate the prognostic miRNAs of triple negative breast cancer. First, using survival analysis, 56 prognostic miRNAs which had a significant...
Unsupervised Neuronal Spike Sorting by Deep Learning Methods
, M.Sc. Thesis Sharif University of Technology ; Sharifi Zarchi, Ali (Supervisor)
Abstract
Unsupervised neural spike sorting is a crucial tool in studying neural systems in the resolution of a neural cell. In extracellular recording from neural cells, the voltage of media is captured by the electrodes. The situation is possible that an electrode record activity of multiple neurons at the same time. The spike sorting goal is assigning each spike (extracellular recorded neural action potential) to a neural cell that generates it. Conventionally, more than one electrode is used to recording media voltages. The electrodes are placed in a small space as a single device called a multi-electrode array. After the spike sorting procedure, the occurrence time of activity of several cells is...
Cancer Detection Classification by cfDNA Methylation
, M.Sc. Thesis Sharif University of Technology ; Sharifi Zarchi, Ali (Supervisor)
Abstract
Traditional techniques use invasive histology techniques to diagnose cancer. Cancer tissue is sampled directly in this method, which is very painful for the patient. In recent years, scientists have discovered that the cell world is released into the blood plasma after cell death, obtaining useful cancer information. Since methylation changes in cancer cells are very significant and the death rate of cancer cells is high, the methylation of each tissue is different from the other. Furthermore, they were diagnosing the type of cancer.On the other hand, due to the different patterns in methylated DNA with normal DNA and the use of bisulfite treatment technique to detect the degree of...
Multi-omic Single-cell Data Integration Using Deep Neural Networks
, M.Sc. Thesis Sharif University of Technology ; Sharifi Zarchi, Ali (Supervisor)
Abstract
The advent and advance of single-cell technologies have enabled us to measure the cell function and identity by using different assays and viewing it by different technologies. Nowadays, we are able to measure multiple feature vectors from same- single cells from multiple abstract molecular levels (genome, transcriptome, proteome, ...) simultaneously. Hence, the analysts can view the cell from different yet correlated angles and study their behaviours. Such progress in joint single-cell assessments plus the development and spread of more common single-cell assays - that measure one feature vector per cell - caused the growing need for computational tools to integrate these datasets in order...
Developing Active Learning Methods to Improve Classification of Medical Images
, M.Sc. Thesis Sharif University of Technology ; Sharifi Zarchi, Ali (Supervisor)
Abstract
With the growing use of machine learning algorithms, especially in deep neural networks, the need for annotated data for supervised learning has also increased. In many cases, it is possible to collect data widely, but annotating all of these data is usually very time-consuming, expensive, and even impossible in some cases. The goal of active learning algorithms is to maximize the model’s performance with the least annotated data. Active learning algorithms are iterative algorithms that train the model in each iteration with the current annotated data. Then, using the results of the model on the remaining data without annotation, select some new data to annotate. This process usually...
FAME: fast and memory efficient multiple sequences alignment tool through compatible chain of roots
, Article Bioinformatics ; Volume 36, Issue 12 , 15 June , 2020 , Pages 3662-3668 ; Parvinnia, E ; Sharifi Zarchi, A ; Sharif University of Technology
Oxford University Press
2020
Abstract
Motivation: Multiple sequence alignment (MSA) is important and challenging problem of computational biology. Most of the existing methods can only provide a short length multiple alignments in an acceptable time. Nevertheless, when the researchers confront the genome size in the multiple alignments, the process has required a huge processing space/time. Accordingly, using the method that can align genome size rapidly and precisely has a great effect, especially on the analysis of the very long alignments. Herein, we have proposed an efficient method, called FAME, which vertically divides sequences from the places that they have common areas; then they are arranged in consecutive order. Then...
A new multiple dna and protein sequences alignment method based on evolutionary algorithms
, Article Journal of Knowledge and Health in Basic Medical Sciences ; Volume 16, Issue 1 , 2021 , Pages 13-20 ; 1735577X (ISSN) ; Parvinnia, E ; Sharifi Zarchi, A ; Sharif University of Technology
Shahroud University of Medical Sciences
2021
Abstract
Introduction: The study of life and the detection of gene functions is an important issue in biological science. Multiple sequences alignment methods measure the similarity of DNA sequences. Nonetheless, when the size of genome sequences is increased, we encounter with the lack of memory and increasing the run time. Therefore, a fast method with a suitable accuracy for genome alignment has a significant impact on the analysis of long sequences. Methods: We introduce a new method in which, it first divides each sequence into short sequences. Then, it uses evolutionary algorithms to align the sequences. Results: The proposed method has been evaluated in seven datasets with different number of...
Dna-Rna hybrid (R-loop): From a unified picture of the mammalian telomere to the genome-wide profile
, Article Cells ; Volume 10, Issue 6 , 2021 ; 20734409 (ISSN) ; Sharifi Zarchi, A ; Kianmehr, L ; Sharif University of Technology
MDPI
2021
Abstract
Local three-stranded DNA/RNA hybrid regions of genomes (R-loops) have been detected either by binding of a monoclonal antibody (DRIP assay) or by enzymatic recognition by RNaseH. Such a structure has been postulated for mouse and human telomeres, clearly suggested by the identification of the complementary RNA Telomeric repeat-containing RNA “TERRA”. However, the tremendous disparity in the information obtained with antibody-based technology drove us to investigate a new strategy. Based on the observation that DNA/RNA hybrids in a triplex complex genome co-purify with the double-stranded chromosomal DNA fraction, we developed a direct preparative approach from total protein-free cellular...
InterOpt: improved gene expression quantification in qPCR experiments using weighted aggregation of reference genes
, Article iScience ; Volume 26, Issue 10 , 2023 ; 25890042 (ISSN) ; Rahmani, S ; Sharifi Zarchi, A ; Sharif University of Technology
Elsevier Inc
2023
Abstract
qPCR is still the gold standard for gene expression quantification. However, its accuracy is highly dependent on the normalization procedure. The conventional method involves using the geometric mean of multiple study-specific reference genes (RGs) expression for cross-sample normalization. While research on selecting stably expressed RGs is extensive, scant literature exists regarding the optimal approach for aggregating multiple RGs into a unified RG. In this paper, we introduce a family of scale-invariant functions as an alternative to the geometric mean aggregation. Our candidate method (weighted geometric mean minimizing standard deviation) demonstrated significantly better results...
Improving Peptide-MHC Class I Binding Prediction using Cross-Encoder Transformer Models
, M.Sc. Thesis Sharif University of Technology ; Sharifi Zarchi, Ali (Supervisor)
Abstract
The Major Histocompatibility Complex (MHC) Class I molecules play a crucial role in the immune system. These molecules present peptides derived from intracellular proteins on the cell surface to be recognized by T cells. This process is vital for identifying and eliminating cancerous or infected cells. In cancer therapy, particularly in the development of personalized vaccines, accurately selecting peptides that can effectively bind to MHC Class I and stimulate a strong immune response is a significant challenge. This research introduces an innovative neural network model that utilizes a cross-encoder architecture and leverages a pre-trained model to simultaneously process peptide and MHC...
Analysis of DNA Methylation in Single-cell Resolution Using Algorithmic Methods and Deep Neural Networks
, M.Sc. Thesis Sharif University of Technology ; Sharifi Zarchi, Ali (Supervisor)
Abstract
DNA methylation in one of the most important epigenetic variations, which causes significant variations in gene expressions of mammalians. Our current knowledge about DNA methylation is based on measurments from samples of bulk data which cause ambiguity in intracellular differences and analysis of rare cell samples. For this reason, the ability to measure DNA methylation in single-cells has the potential to play an important role in understanding many biological processes including embryonic developement, disease progression including cancer, aging, chromosome instability, X chromosome inactivation, cell differentiation and genes regulation. Recent technological advances have enabled...
Prediction of HLA-Peptide Binding using 3D Structural Features
, M.Sc. Thesis Sharif University of Technology ; Sharifi Zarchi, Ali (Supervisor)
Abstract
The human leukocyte antigen protein, commonly known as HLA, has the ability to present small protein fragments called peptides on the surface of cells, whether they originate from within the cell or externally. The binding of these peptides to HLA receptors is a crucial step that triggers an immune response. By estimating the affinity between peptides and HLA class I, we can identify novel antigens that have the potential to be targeted by cancer therapeutic vaccines. Computational methods that predict the binding affinity between peptides and HLA receptors have the potential to expedite the design process of cancer vaccines. Currently, most computational methods exclusively rely on...
DeePathology: Deep multi-task learning for inferring molecular pathology from cancer transcriptome
, Article Scientific Reports ; Volume 9, Issue 1 , 2019 ; 20452322 (ISSN) ; Saberi, A ; Chitsaz, H ; Sharifi Zarchi, A ; Sharif University of Technology
Nature Publishing Group
2019
Abstract
Despite great advances, molecular cancer pathology is often limited to the use of a small number of biomarkers rather than the whole transcriptome, partly due to computational challenges. Here, we introduce a novel architecture of Deep Neural Networks (DNNs) that is capable of simultaneous inference of various properties of biological samples, through multi-task and transfer learning. It encodes the whole transcription profile into a strikingly low-dimensional latent vector of size 8, and then recovers mRNA and miRNA expression profiles, tissue and disease type from this vector. This latent space is significantly better than the original gene expression profiles for discriminating samples...
Characterization of nitrocarburized surface layer on AISI 1020 steel by electrolytic plasma processing in an urea electrolyte
, Article Journal of Materials Research and Technology ; Volume 2, Issue 3 , 2013 , Pages 213-220 ; 22387854 (ISSN) ; Shariat, M.H ; Dehghan, S. A ; Solhjoo, S ; Sharif University of Technology
Elsevier Editora Ltda
2013
Abstract
In this study, electrolytic plasma processing (EPP) was employed for surface nitrocarburizing of AISI 1020 steel in a urea electrolyte, where the substrate samples were connected cathodically to a high-voltage DC current power supply. The structural, mechanical, wear and corrosion properties of the samples treated for 3-5 min were investigated. The results show that the surface layers formed on the samples by this treatment at 220 V have a ferritic nitrocarburizing characteristic which consists of a compound layer and diffusion zone. The surface layers of the treated samples at 240 V consisted of a compound layer, martensitic layer and diffusion zone, respectively, which is a marker of...
The assessment of efficient representation of drug features using deep learning for drug repositioning
, Article BMC Bioinformatics ; Volume 20, Issue 1 , 2019 ; 14712105 (ISSN) ; Ghadirinia, M ; Sharifi Zarchi, A ; Zare Mirakabad, F ; Sharif University of Technology
BioMed Central Ltd
2019
Abstract
Background: De novo drug discovery is a time-consuming and expensive process. Nowadays, drug repositioning is utilized as a common strategy to discover a new drug indication for existing drugs. This strategy is mostly used in cases with a limited number of candidate pairs of drugs and diseases. In other words, they are not scalable to a large number of drugs and diseases. Most of the in-silico methods mainly focus on linear approaches while non-linear models are still scarce for new indication predictions. Therefore, applying non-linear computational approaches can offer an opportunity to predict possible drug repositioning candidates. Results: In this study, we present a non-linear method...
The metabolic network model of primed/naive human embryonic stem cells underlines the importance of oxidation-reduction potential and tryptophan metabolism in primed pluripotency
, Article Cell and Bioscience ; Volume 9, Issue 1 , 2019 ; 20453701 (ISSN) ; Marashi, S. A ; Sharifi Zarchi, A ; Taleahmad, S ; Sharif University of Technology
BioMed Central Ltd
2019
Abstract
Background: Pluripotency is proposed to exist in two different stages: Naive and Primed. Conventional human pluripotent cells are essentially in the primed stage. In recent years, several protocols have claimed to generate naive human embryonic stem cells (hESCs). To the best of our knowledge, none of these protocols is currently recognized as the gold standard method. Furthermore, the consistency of the resulting cells from these diverse protocols at the molecular level is yet to be shown. Additionally, little is known about the principles that govern the metabolic differences between naive and primed pluripotency. In this work, using a computational approach, we tried to shed light on...
Binding Affinity Prediction Between Antibody and Antigen using Self-Supervised Learning
, M.Sc. Thesis Sharif University of Technology ; Sharifi Zarchi, Ali (Supervisor)
Abstract
In recent years, monoclonal antibodies have gained attention as highly effective drugs for treating diseases, especially cancer. The high binding affinity between an antibody and its corresponding antigen is one of the key factors in triggering an effective immune response. Modeling binding affinity using machine learning is considered a promising and cost-effective computational approach; however, due to the lack of training data, the performance of these models is often poor and limited. In contrast, recent advances in geometric learning have demonstrated that incorporating the three-dimensional geometry of protein structures in the learning process can significantly impact 3D...
StrongestPath: a Cytoscape application for protein-protein interaction analysis
, Article BMC bioinformatics ; Volume 22, Issue 1 , 2021 , Pages 352- ; 14712105 (ISSN) ; Khodabandeh, M ; Sharifi Zarchi, A ; Nadafian, A ; Mahmoudi, A ; Sharif University of Technology
NLM (Medline)
2021
Abstract
BACKGROUND: StrongestPath is a Cytoscape 3 application that enables the analysis of interactions between two proteins or groups of proteins in a collection of protein-protein interaction (PPI) network or signaling network databases. When there are different levels of confidence over the interactions, the application is able to process them and identify the cascade of interactions with the highest total confidence score. Given a set of proteins, StrongestPath can extract a set of possible interactions between the input proteins, and expand the network by adding new proteins that have the most interactions with highest total confidence to the current network of proteins. The application can...
Machine Learning Approaches for the Prediction of Pathogenicity in Genome Variations
, M.Sc. Thesis Sharif University of Technology ; Sharifi Zarchi, Ali (Supervisor) ; Asgari, Ehsannedin (Supervisor)
Abstract
Genome mutations whose effects are not specified pose one of the challenges in identifying genetic diseases. Utilizing wet lab tests to detect the pathogenicity of variants can be time-consuming and fiscally expensive. A rapid and cost-effective solution to this problem is the use of machine learning-based variant effect predictors, which have the ability to determine whether a mutation is pathogenic or not. The objective of this research is to predict the pathogenicity of genome variations. The proposed model exclusively utilizes the protein sequence as its input feature and does not have access to other protein features. The data used to construct the model comprises mutations with...