27 research outputs found
Phase Transition Analysis of the Dynamic Instability of Microtubules
This paper provides the phase transition analysis of a reaction diffusion
equations system modeling dynamic instability of microtubules. For this purpose
we have generalized the macroscopic model studied by Mour\~ao et all [MSS].
This model investigates the interaction between the microtubule nucleation,
essential dynamics parameters and extinction and their impact on the stability
of the system. The considered framework encompasses a system of partial
differential equations for the elongation and shortening of microtubules, where
the rates of elongation as well as the lifetimes of the elongating shortening
phases are linear functions of GTP-tubulin concentration. In a novel way, this
paper investigates the stability analysis and provides a bifurcation analysis
for the dynamic instability of microtubules in the presence of diffusion and
all of the fundamental dynamics parameters. Our stability analysis introduces
the phase transition method as a new mathematical tool in the study of
microtubule dynamics. The mathematical tools introduced to handle the problem
should be of general use
Physics Informed Recurrent Neural Networks for Seismic Response Evaluation of Nonlinear Systems
Dynamic response evaluation in structural engineering is the process of
determining the response of a structure, such as member forces, node
displacements, etc when subjected to dynamic loads such as earthquakes, wind,
or impact. This is an important aspect of structural analysis, as it enables
engineers to assess structural performance under extreme loading conditions and
make informed decisions about the design and safety of the structure.
Conventional methods for dynamic response evaluation involve numerical
simulations using finite element analysis (FEA), where the structure is modeled
using finite elements, and the equations of motion are solved numerically.
Although effective, this approach can be computationally intensive and may not
be suitable for real-time applications. To address these limitations, recent
advancements in machine learning, specifically artificial neural networks, have
been applied to dynamic response evaluation in structural engineering. These
techniques leverage large data sets and sophisticated algorithms to learn the
complex relationship between inputs and outputs, making them ideal for such
problems. In this paper, a novel approach is proposed for evaluating the
dynamic response of multi-degree-of-freedom (MDOF) systems using
physics-informed recurrent neural networks. The focus of this paper is to
evaluate the seismic (earthquake) response of nonlinear structures. The
predicted response will be compared to state-of-the-art methods such as FEA to
assess the efficacy of the physics-informed RNN model
Drug Repurposing for Age-Related Macular Degeneration (AMD) Based on Gene Co-Expression Network Analysis
Background: Age-related macular degeneration (AMD) is a lesser-known eye disease in the world that gradually destroys a person’s vision by creating dark spots in the center of vision. Material and Methods: Samples of AMD-related genes were extracted from the NCBI, then the gene expression network (GCN) was extracted. In addition, pathway enrichment analysis was performed to investigate the role of co-expressed genes in AMD. Finally, the drug-gene interaction network was plotted.Results: The results of this work based on bioinformatics showed that many genes are involved in AMD disease, the most important of which are the genes of TYROBP, LILRB2, LCP2, PTPRC, CFH, SPARC, HTR5A.Overexpression of these genes can be considered as basic biomarkers for this disease, we separated some of which we had from the gene co-expression network and some from the results of genes ontology (genes that have a P value ≤ 0.05). The most important drugs were isolated from the drug-gene network based on degree, which included 5 drugs including ocriplasmin, collagenase clostridium histolyticum, topiramate, primidone, butalbital.Conclusion: Among the genes we found, three genes of CFH, TYROBP, SPARC seem to be more important than the others. Among drugs, ocriplasmin, topiramate, primidone can play a more important role based on the degree in the drug-gene network, because all steps are performed with different bioinformatics methods, clinical trials must confirm or reject the results.Keywords: Age-Related Macular Degeneration; AMD; Co-Expression Network; Drug Repurposing
Anti-Cancer Drugs Effective in Retinoblastoma: Based on a Protein-Protein Interaction Network
Background: This paper investigates the effects of potential drugs on differentially expressed genes (DEGs) associated with substantial alterations in retinoblastoma malignancy.Material and Methods: The GSE125903 dataset consisting of ten samples was used in this study (seven cancer patients and three control samples). The genes were ordered according to their adjusted p value, and 2000 top differential expressed genes with adj p values less than 0.01 were chosen as statistically significant. The STRING database version 11.0 was used to display the interaction among genes. The Cytoscape3.8.2 and the Clusterviz plugin software were used to construct the modules for the PPI network, and five clusters of genes were formed. The DGIdb v4.2.0 database was used to study drug-gene interactions and identify potentially beneficial medicines for retinoblastoma malignancy. The DAVID v.6.8 database was used to study gene ontology (GO) and important biological pathways.Results: CISPLATIN, TAMOXIFEN, and CYCLOPHOSPHAMIDE are the medicines that have been shown to be successful in treating retinoblastoma in our study. Additionally, we conducted a research on three other drugs: GEMCITABINE, OLAPARIB, and MITOXANTRONE. Although it is used to treat other diseases, it seems to have no apparent effects on retinoblastoma cancer treatment.Conclusion: CISPLATIN, a drug that causes apoptosis in tumors, has been proven to be the most effective therapy for retinoblastoma and should be included in treatment regimens for this illness. Of course, we obtained this information based on bioinformatics techniques, and more clinical trials are needed for more reliable results.Keywords: Protein-Protein Interaction Network; Retinoblastoma; Anti-Cancer
Skip-WaveNet: A Wavelet based Multi-scale Architecture to Trace Firn Layers in Radar Echograms
Echograms created from airborne radar sensors capture the profile of firn
layers present on top of an ice sheet. Accurate tracking of these layers is
essential to calculate the snow accumulation rates, which are required to
investigate the contribution of polar ice cap melt to sea level rise. However,
automatically processing the radar echograms to detect the underlying firn
layers is a challenging problem. In our work, we develop wavelet-based
multi-scale deep learning architectures for these radar echograms to improve
firn layer detection. We show that wavelet based architectures improve the
optimal dataset scale (ODS) and optimal image scale (OIS) F-scores by 3.99% and
3.7%, respectively, over the non-wavelet architecture. Further, our proposed
Skip-WaveNet architecture generates new wavelets in each iteration, achieves
higher generalizability as compared to state-of-the-art firn layer detection
networks, and estimates layer depths with a mean absolute error of 3.31 pixels
and 94.3% average precision. Such a network can be used by scientists to trace
firn layers, calculate the annual snow accumulation rates, estimate the
resulting surface mass balance of the ice sheet, and help project global sea
level rise