Sharif Digital Repository

The graphene-based materials with unique, versatile, and tunable properties have brought new opportunities for the leading edge of advanced nanobiotechnology. In this regard, the use of graphene in gene delivery applications is still at early stages. In this study, we successfully designed a new complex of carboxylated-graphene (G-COOH) with ethidium bromide (EtBr) and used it as a nanovector for efficient gene delivery into the AGS cells. G-COOH, with carboxyl functions on its surface, in the presence of EtBr, formaldehyde, and cyclohexylisocyanide were participated in Ugi four component reaction to fabricate a stable amphiphilic graphene-EtBr (AG-EtBr) composite. The coupling reaction was... 

Graphene-based materials are revealing the leading edge of advanced technology for their exceptional physical and chemical properties. Chemical manipulation on graphene surface to tailor its unique properties and modify atomic structures is being actively pursued. Therefore, the discovery of robust and general protocols to anchor active functionality on graphene basal plane is still of great interest. Multicomponent reactions promise an enormous level of interest due to addressing both diversity and complexity in combinatorial synthesis, in which more than two starting compounds react to form a product derived from entire inputs. In this article, we present the first covalent... 

Additive manufacturing, artificial intelligence and cloud manufacturing are three pillars of the emerging digitized industrial revolution, considered in industry 4.0. The literature shows that in industry 4.0, intelligent cloud based additive manufacturing plays a crucial role. Considering this, few studies have accomplished an integration of the intelligent additive manufacturing and the service oriented manufacturing paradigms. This is due to the lack of prerequisite frameworks to enable this integration. These frameworks should create an autonomous platform for cloud based service composition for additive manufacturing based on customer demands. One of the most important requirements of... 

By intense growth in the field of 3D printing, new opportunities for manufacturing firms and individuals have been created to benefit from the flexibility in production and personalized products. However, the need for human agents for additive process planning and control results in more operating costs and less agility in 3D printing. So, it is necessary to have autonomous mechanisms for fulfilling the additive process planning. This paper has benefited from the recent advancements of artificial intelligence to create a basis for an autonomous system which decides upon the build orientation of the shape, based on the previously encountered occurrences of parts which were similar to its... 

In this paper a web based production system is proposed. This system consists of a web services agent to manage the receipt the order from the customer, a price agent to predict the price of the product for the customer, a decision agent to build up a virtual enterprise to manufacture and deliver of the product to the customer and make essential decisions of the system and a design and control agent to do the engineering tasks related to the production process of the product. This structure provides the production system with a high level of agility and flexibility. © 2019 IEEE  

Utilization of nanoparticles in oil and gas industry has attracted considerable attention of engineers and researchers. In this article, the feasibility of nanoemulsion flooding is investigated as a method for Enhanced Oil Recovery (EOR) through coreflooding experiments, using a packed bed and real reservoir fluids. Nine different mixtures of the solvent, surfactant, and nanoparticles in the form of a nanoemulsion phase are generated and used to recover the oil in the context of an EOR process. Various tests are conducted to determine the properties of porous medium and fluids. To study the production performance of this EOR technique, pressure drop across the packed bed are measured, along... 

In this paper, "Subspace" method is generalized to asymmetrical case. In the new algorithm described here, "Lanczos" method is used to find the first subspace and to solve the eigenvalue problem resulted in generalized subspace method. To solve the standard eigenvalue problem developed by "Lanczos" method "Jacoby" method is used. If eigenvalue problem includes damping matrix, that will be imported in new defined mass and stiffness matrices  

Chronic inflammatory demyelinating polyneuropathy (CIDP) is an acquired immunological disorder. Although the precise pathoetiology of CIDP has not been clarified yet, it is believed that both B and T cells of immune system contribute in this disorder. Based on the importance of human leukocyte antigen (HLA) cluster in the regulation of immune responses, this family of proteins is putative determinants of risk of CIDP. We conducted the current investigation to appraise association between HLA alleles/genotypes/haplotypes and risk of CIDP in Iranian patients. HLA-DQB1*02 allele was significantly more prevalent among cases compared with controls (OR [95% CI] = 4.82 [2.06, 11.3], P value =... 

Carbon-based quantum dots (CDs) are mainly divided into two sub-groups; carbon quantum dots (CQDs) and graphene quantum dots (GQDs), which exhibit outstanding photoluminescence (PL) properties, low toxicity, superior biocompatibility and facile functionalization. Regarding these features, they have been promising candidates for biomedical science and engineering applications. In this work, we reviewed the efforts made to modify these zero-dimensional nano-materials to obtain the best properties for bio-imaging, drug and gene delivery, cancer therapy, and bio-sensor applications. Five main surface modification techniques with outstanding results are investigated, including doping, surface... 

Carbon-based quantum dots (CDs) are mainly divided into two sub-groups; carbon quantum dots (CQDs) and graphene quantum dots (GQDs), which exhibit outstanding photoluminescence (PL) properties, low toxicity, superior biocompatibility and facile functionalization. Regarding these features, they have been promising candidates for biomedical science and engineering applications. In this work, we reviewed the efforts made to modify these zero-dimensional nano-materials to obtain the best properties for bio-imaging, drug and gene delivery, cancer therapy, and bio-sensor applications. Five main surface modification techniques with outstanding results are investigated, including doping, surface... 

Chronic inflammatory demyelinating polyneuropathy (CIDP) is an acquired immunological disorder. Although the precise pathoetiology of CIDP has not been clarified yet, it is believed that both B and T cells of immune system contribute in this disorder. Based on the importance of human leukocyte antigen (HLA) cluster in the regulation of immune responses, this family of proteins is putative determinants of risk of CIDP. We conducted the current investigation to appraise association between HLA alleles/genotypes/haplotypes and risk of CIDP in Iranian patients. HLA-DQB1*02 allele was significantly more prevalent among cases compared with controls (OR [95% CI] = 4.82 [2.06, 11.3], P value =... 

Control of unstable non-minimum-phase delayed stochastic processes is a challenging problem. In this work based on the Diophantine equation and using pole-placement technique, a discrete control scheme for such processes has been proposed. Robust stability of the suggested control structure has been shown. Advantages of the proposed scheme over the existing algorithms have been shown through computer simulations. It has been shown that performance of the proposed scheme for handling model mismatch and colored noise is superior to the previous work proposed in the literature  

This article indicates the accurate method for load level calculation to solve the power flow problem when capacitor reactive power is involved. Using the correct method causes some changes in the results and conclusion stated in the discussed paper on optimal reconfiguration and capacitor placement in radial distribution systems  

Purpose - The purpose of this paper is to describe optical flow-based navigation of a very light fixed-wing aircraft in flight between obstacles. Design/methodology/approach - The optical flow information of two cameras mounted on the aircraft is used to detect the obstacle. It is assumed that the image processing has been completed and the optical flow vectors have been obtained beforehand. The optical flow is used to detect the obstacles and make a rapid turn manoeuvre for the aircraft. Findings - It is shown that using the optical flow feedback by itself is unable to give a rapid turn to the aircraft and its rate should be employed into the control law. Six degree-of-freedom flight... 

Capacitor placement/setting is one of the main means for loss reduction and voltage profile improvement in distribution systems. If capacitor placement is meant, the objective function will be the cost of energy losses besides the capacitors costs in a specified period of time. Here, reconfiguration can be used as a strategy to reform the base configuration of the distribution network in order to place the capacitors more efficiently with lower costs. On the other hand, if capacitors are already available in a network, optimum capacitors setting and network reconfiguration should be performed for power loss minimization. In this paper both power loss minimization and capacitor placement cost... 

This paper reports on the diversity of languages displayed in the linguistic landscape of Julfa district, a largely Armenian dominated area, in the city of Isfahan in Iran. The data included a corpus of 323 photographs taken from the top-down and bottom-up signage in this quarter of the city. Ethnographic fieldwork was also conducted to reach a deeper understanding of the linguistic landscape in Julfa. The results of the analyses indicated that Julfa, as home to Armenians in diaspora and also a luxurious neighborhood frequented by more modern strata of the Isfahani society, is occupied more noticeably with Persian and English language and to a lesser extent with Armenian language. The... 

Purpose: The purpose of this paper is to investigate the English for publication purpose practices of doctoral students in Iran. The overall objective was to explore their motives, hurdles and strategies in academic writing. Design/methodology/approach: This case study draws on a narrative inquiry to explore nine science and engineering doctoral students’ perceptions of academic publication. The data were analyzed through a hybrid process of inductive and deductive thematic analysis. Findings: The qualitative results showed three dominant themes, namely: motives for publication, hurdles to publication and strategies for dealing with these challenges were extracted. The main sources of... 

This survey investigated the cultural identity of Iranian English language teachers. Accordingly, a cultural identity model was proposed a priori, based on which a questionnaire was developed and piloted on 50 Iranian English language teachers (α = 0.87). The developed questionnaire was then administered to 636 male and female Iranian English language teachers. The results of confirmatory factor analysis showed that the model was fit and eight components namely 1) religious beliefs, 2) history, 3) customs, 4) manners and behaviors, 5) Persian language, 6) literature and art, 7) parents’ influence and 8) family relations were confirmed to form the core of Iranian cultural identity. The... 

The present mixed-methods research examined the identity and attitude of Iranian English language learners as a result of their participation in an online critical reflective course. The participants were 38 English language students who attended ten online sessions within a five-month English language course. Their online posts underwent inductive qualitative content analysis and subsequently five themes were extracted. In addition, the content of the first and last two sessions were analysed quantitatively. A validated questionnaire was also administered and 18 participants were interviewed. Qualitative and quantitative content analyses of the data revealed eight finalised codes. The... 

Cloud computing and web applications have further highlighted the need for powerful data centers with large bandwidth and low power consumption. In order to provide such a large bandwidth, today's electronic data centers require high power levels. Furthermore, communications and devices are not always used to their full potential. Optical networks can be a proper option for data centers, as they can offer large and variable bandwidth with lower power consumption compared to their electronic counterparts. In this regard, a dynamic all-optical network architecture is proposed in this paper, with bandwidth reconfiguration capability and low latency to reduce energy consumption. This proposed...