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Ebrahimi, Saeed,Salahshoor, Esmaeil,Moradi, Shapour Techno-Press 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.63 No.5
Clearances are essential for the assemblage of mechanisms to allow the relative motion between the joined bodies. This clearance exists due to machining tolerances, wear, material deformations, and imperfections, and it can worsen the mechanism performance when the precision and smoothly-working are intended. Energy is a subject which is less paid attention in the area of clearance. The effect of the clearance on the energy of a flexible slider-crank mechanism is investigated in this paper. A clearance exists in the joint between the slider and the coupler. The contact force model is based on the Lankarani and Nikravesh model and the friction force is calculated using the modified Coulomb's friction law. The hysteresis damping which has been included in the contact force model dissipates energy in clearance joints. The other source for the energy loss is the friction between the journal and the bearing. Initial configuration and crank angular velocity are changed to see their effects on the energy of the system. Energy diagrams are plotted for different coefficients of friction to see its influence. Finally, considering the coupler as a flexible body, the effect of flexibility on the energy of the system is investigated.
Saeed Ebrahimi,Esmaeil Salahshoor,Shapour Moradi 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.63 No.5
Clearances are essential for the assemblage of mechanisms to allow the relative motion between the joined bodies. This clearance exists due to machining tolerances, wear, material deformations, and imperfections, and it can worsen the mechanism performance when the precision and smoothly-working are intended. Energy is a subject which is less paid attention in the area of clearance. The effect of the clearance on the energy of a flexible slider-crank mechanism is investigated in this paper. A clearance exists in the joint between the slider and the coupler. The contact force model is based on the Lankarani and Nikravesh model and the friction force is calculated using the modified Coulomb\'s friction law. The hysteresis damping which has been included in the contact force model dissipates energy in clearance joints. The other source for the energy loss is the friction between the journal and the bearing. Initial configuration and crank angular velocity are changed to see their effects on the energy of the system. Energy diagrams are plotted for different coefficients of friction to see its influence. Finally, considering the coupler as a flexible body, the effect of flexibility on the energy of the system is investigated.
Amiri, Boshra,Ebrahimi-Far, Meysam,Saffari, Zahra,Akbarzadeh, Azim,Soleimani, Esmaeil,Chiani, Mohsen Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.8
Background: Breast cancer is one of the most frequent cancer types within female populations. Silibinin is a chemotherapeutic agent ative against cancer. Niosomes are biodegradable, biocompatible, safe and effective carriers for drug delivery. Objective:To prepare nanoniosomal silibinin and evaluate its cytotoxicity inthe T-47D breast cancer cell line. Materials and Methods: Niosomes were prepared by reverse phase evaporation of a mixture of span 20, silibinin, PEG-2000 and cholesterol in chloroform and methanol solvent (1:2 v/v). The solvent phase was evaporated using a rotary evaporator and the remaining gel phase was hydrated in phosphate buffer saline. Mean size, size distribution and zeta potential of niosomes were measured with a Zetasizer instrument and then nanoparticles underwent scanning electron microscopy. The drug releasing pattern was evaluated by dialysis and the cytotoxicity of nanoniosomes in T-47D cells was assessed by MTT assay. Results: Particle size, size variation and zeta potential of the niosomal nanoparticles were measured as $178.4{\pm}5.4nm$, $0.38{\pm}0.09$ and $-15.3{\pm}1.3mV$, respectively. The amount of encapsulated drug and the level of drug loading were determined $98.6{\pm}2.7%$ and $22.3{\pm}1.8%$, respectively; released drug was estimated about $18.6{\pm}2.5%$ after 37 hours. The cytotoxic effects of nanoniosome were significantly increased when compared with the free drug. Conclusions: This study finding suggests that silibinin nanoniosomes could serve as a new drug formulation for breast cancer therapy.
Transcriptional regulatory network analysis of the over-expressed genes in adipose tissue
Mohammad Reza Bakhtiarizadeh,Esmaeil Ebrahimie,Mohammad Moradi-Shahrbabak 한국유전학회 2014 Genes & Genomics Vol.36 No.1
Adipose tissue plays important roles in wholebody energy homeostasis and is now known to be a veryimportant and active endocrine organ. The transcriptionalregulatory network of adipose tissue metabolism is complexand much yet to be known. To identify transcriptionalprofile in adipose tissue, expressed sequence tag (EST)analysis using Digital Differential Display (DDD) wasemployed. The results of EST analysis were re-evaluatedby microarray data using COXPRESdb (an availableexpression data repository). To uncover transcriptionalregulatory mechanisms which play key roles in the adiposetissue metabolism, transcriptional regulatory network analysiswas applied, using the promoter analysis and interactionnetwork toolset. Sixty-five transcripts were found tobe more frequent in adipose tissue in comparison to theother tissues. COXPRESdb result showed that 62 % of the identified over-expressed genes in adipose tissue by DDDhad expression level greater than 1 (in base 2 logarithm). Based on coincidence of regulatory sites, candidate TFswere identified including TFs that previously known to beinvolved in adipose tissue metabolism (SP1, KROX,STAT1, LRF, VDR, LXR, SRF and HIF1) and TFs, such asCKROX, ZF5, ETF, AP-2, AP-2alpha, PAX-5, SPZ1,RBPJ and CACD, that had not been recognized previously. This work yielded several TF candidates activating inadipose tissue metabolism. These findings open a newavenue for future research on promoter occupancy and TFperturbation.
Ehsan Tahrokh,Mansour Ebrahimi,Mahdi Ebrahimi,Fatemeh Zamansani,Narjes Rahpeyma Sarvestani,Manijeh Mohammadi-Dehcheshmeh,Mohammad Reza Ghaemi,Esmaeil Ebrahimie 한국유전학회 2011 Genes & Genomics Vol.33 No.5
Ammonium is an excellent nitrogen source, and ammonium transfer is a fundamental process in most organisms. Membrane transport of ammonium is the key component of nitrogen metabolism mediated by Ammonium Transporter/Methylamine Permease/Rhesus (AMT/MEP/Rh) protein family. Ammonium transporters play different physiological roles in various organisms. Here, we looked at the protein characteristics of ammonium transporters in different organisms to create a link between protein characteristics and the organism. In order to increase the accuracy and precision of the employed models,for the first time, an attempt was made to cover all structural aspects of ammonium transporters in animals, bacteria, fungi,plants, and human by extracting and calculating 874 protein attributes of primary, secondary, and tertiary structures for each ammonium transporter. Then, various weighting and modeling algorithms were applied to determine how structural protein features change between organisms. Considering a large number of protein attributes made it possible to detect key protein characteristics in the structure of ammonium transporters. The results, for the first time, indicated that His-based features including count/frequency of His and frequency/count of Ile-His were the most significant features generating different types of ammonium transporters within organisms. Within different tested models, the C5.0 model was the most efficient and precise model for discrimination of organism type, based on ammonium transporter sequence, with the precision of 94.85%. The determination of protein characteristics of ammonium transporters in different organisms provides a new vista for understanding the evolution of transporters based on the modulation of protein characteristics and facilitates engineering of new transporters. In our point of view, dissecting a large number of structural protein characteristics through data mining algorithms provides a novel functional strategy for studying evolution and phylogeny. This research will serve as a basis for future studies on engineering novel ammonium transporters.
Gadobutrol-dendrimer effects on metastatic and apoptotic gene expression
Kebriaezadeh, Abbas,Ashrafi, Sepehr,Rasouli, Rahimeh,Ebrahimi, Seyed Esmaeil Sadat,Hamedani, Morteza Pirali,Assadi, Artin,Saffari, Mostafa,Ardestani, Mehdi Shafiee Techno-Press 2016 Advances in nano research Vol.4 No.2
Dendrimers are one of the most appropriate nanocaries for imaging moieties in imaging applications.The purpose of this study was the evalution of cytotoxicity and inducing apoptosis of dendrimers. This study was conducted in order to investigate the metastasis suppression effect of dendrimer in human breast MCF-7 cell line and finding the nanoparticle protein corona in biological enviromental. Dendrimer cytotoxicity effect was assessed by MTT assay. The mRNA experession level of KAI1 as a metastasis suppressor gene, Bax as Pro- apoptotic gene, Bcl-2 as an anti-apoptotic gene and GAPDH as a housekepping gene were determined by real-time PCR assays.concentration-dependent nanoparticle cytotoxicity effect was proofed at range of 1-2 mg/mL in 24 hours, significant upregulation of mRNA expression of Bax, was observed whereas expression of anti-apoptotic Bcl-2 was down-regulated, also expression of metastasis suppressor gene KAI1 was up-regulated. So far a few studies confirmed apoptosis enhancement effect of dendrimers in MCF-7 cell line via bax/bcl-2 pathways. dendrimer nanoparticles was able to act as metastase inhibitor via upregulation of KAI1 gene.
New PLA/PEI-functionalized Fe3O4 nanocomposite: Preparation and characterization
Meisam Shabanian,Mehdi Khoobi,Farideh Hemati,Hossein Ali Khonakdar,Seyed esmaeil Sadat ebrahimi,Udo Wagenknecht,Abbas Shafiee 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.24 No.-
In this work, Fe3O4 nanoparticles were functionalized with hyperbranched polyethylenimine (PEI). The neat Fe3O4 nanoparticles (MNP) and functionalized Fe3O4 (MNP@PEI) were separately incorporated into a polylactic acid (PLA). Compared to the neat MNP, the functionalized nanoparticles (MNP@PEI) had better dispersion in the PLA matrix. The properties of the nanocomposites were strongly related to the dispersion and interaction between the nanoparticles and PLA matrix. The heat barrier effect and high nitrogen content of the MNP@PEI nanoparticles were found to be responsible for the improvement of the thermal and flame resistance properties.