Sol–Gel Synthesis and Electrospraying of Biodegradable (P₂O₅)₅₅–(CaO)₃₀–(Na₂O)₁₅ Glass Nanospheres as a Transient Contrast Agent for Ultrasound Stem Cell Imaging

Foroutan, Farzad,Jokerst, Jesse V.,Gambhir, Sanjiv S.,Vermesh, Ophir,Kim, Hae-Won,Knowles, Jonathan C. American Chemical Society 2015 ACS NANO Vol.9 No.2

<P>Ultrasound imaging is a powerful tool in medicine because of the millisecond temporal resolution and submillimeter spatial resolution of acoustic imaging. However, the current generation of acoustic contrast agents is primarily limited to vascular targets due to their large size. Nanosize particles have the potential to be used as a contrast agent for ultrasound molecular imaging. Silica-based nanoparticles have shown promise here; however, their slow degradation rate may limit their applications as a contrast agent. Phosphate-based glasses are an attractive alternative with controllable degradation rate and easily metabolized degradation components in the body. In this study, biodegradable P2O5-CaO-Na2O phosphate-based glass nanospheres (PGNs) were synthesized and characterized as contrast agents for ultrasound imaging. The structure of the PGNs was characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), (31)P magic angle spinning nuclear magnetic resonance P-31 MAS NMR), and Fourier transform infrared (FTIR) spectroscopy. The SEM images indicated a spherical shape with a diameter size range of 200-500 nm. The XRD, P-31 NMR, and FTIR results revealed the amorphous and glassy nature of PGNs that consisted of mainly Q(1) and Q(2) phosphate units. We used this contrast to label mesenchymal stem cells and determined in vitro and in vivo detection limits of 5 and 9 mu g/mL, respectively. Cell counts down to 4000 could be measured with ultrasound imaging with no cytoxicity at doses needed for imaging. Importantly, ion-release studies confirmed these PGNs biodegrade into aqueous media with degradation products that can be easily metabolized in the body.</P>

Asian Migrant Women's Employment Participation : Patterns, Determinants and Differentials

FOROUTAN, Yaghoob,MCDONALD, Peter 이화여자대학교 아시아여성학센터 2008 Asian Journal of Women's Studies(AJWS) Vol.14 No.2

This paper is an empirical investigation into Asian migrant women’s employment participation in Australia. Using the customized tabulations from the 2001 Census of Population and Housing, it examines the patterns and determinants of employment status and occupational levels of Asian-born migrant women and compares their differentials with both non-Asian-born migrants and native-born women in the multiethnic and multicultural context of Australia. The status and success of migrant groups in the labor market has been observed to be a key indication of migrants’ settlement in the destination country, while acknowledging issues of selectivity of migration from Asia to Australia as a multicultural context. The multivariate findings of the study provide a basis for settlement assessment of Asian migrant women.

Effect of dynamic absorber on the nonlinear vibration of SFG cylindrical shell

Foroutan, Kamran,Ahmadi, Habib Techno-Press 2020 Advances in aircraft and spacecraft science Vol.7 No.4

In this paper, a numerical method is utilized to study the effect of a new vibration absorber on vibration response of the stiffened functionally graded (SFG) cylindrical shell under a couple of axial and transverse compressions. The material composition of the stiffeners and shell is continuously changed through the thickness. The vibration absorber consists of a mass-spring-damper system which is connected to the ground utilizing a linear local damper. To simplify, the spring element of the vibration absorber is called global potential. The von Kármán strain-displacement kinematic nonlinearity is employed in the constitutive laws of the shell and stiffeners. To consider the stiffeners in the model, the smeared stiffener technique is used. After obtaining the governing equations, the Galerkin method is applied to discretize the nonlinear dynamic equation of system. In order to find the nonlinear vibration responses, the fourth order Runge-Kutta method is utilized. The influence of the stiffeners, the dynamic absorber parameters on the vibration behavior of the SFG cylindrical shell is investigated. Also, the influences of material parameters of the system on the vibration response are examined.

Nonlinear dynamic analysis of spiral stiffened functionally graded cylindrical shells with damping and nonlinear elastic foundation under axial compression

Foroutan, Kamran,Shaterzadeh, Alireza,Ahmadi, Habib Techno-Press 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.66 No.3

The semi-analytical method to study the nonlinear dynamic behavior of simply supported spiral stiffened functionally graded (FG) cylindrical shells subjected to an axial compression is presented. The FG shell is surrounded by damping and linear/nonlinear elastic foundation. The proposed linear model is based on the two-parameter elastic foundation (Winkler and Pasternak). A three-parameter elastic foundation with hardening/softening cubic nonlinearity is used for nonlinear model. The material properties of the shell and stiffeners are assumed to be FG. Based on the classical plate theory of shells and von $K{\acute{a}}rm{\acute{a}}n$ nonlinear equations, smeared stiffeners technique and Galerkin method, this paper solves the nonlinear vibration problem. The fourth order Runge-Kutta method is used to find the nonlinear dynamic responses. Results are given to consider effects of spiral stiffeners with various angles, elastic foundation and damping coefficients on the nonlinear dynamic response of spiral stiffened simply supported FG cylindrical shells.

Post-buckling analysis of sandwich FG porous cylindrical shells with a viscoelastic core

Kamran Foroutan,Liming Dai 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.45 No.3

In this research, an approach combining a semi-analytical method and an analytical method is presented to investigate the static and dynamic post-buckling behavior of the sandwich functionally graded (FG) porous cylindrical shells exposed to external pressure. The sandwich cylindrical shell considered is composed of a viscoelastic core and two FG porous (FGP) face layers. The viscoelastic core is made of Kelvin-Voigt-type material. The material properties of the FG porous face layer are considered continuous through each face thickness according to a porosity coefficient and a volume fraction index. Two types of sandwich FG porous viscoelastic cylindrical shells named Type A and Type B are considered in the research. Type A shell has the porosity evenly distributed across the thickness direction, and Type B has the porosity unevenly distributes across the thickness direction. The FG face layers are considered in two cases: outside metal surface, inside ceramic surface (OMSICS), and inside metal surface, outside ceramic surface (IMS-OCS). According to Donnell shell theory, von-Kármán equation, and Galerkin’s method, a discretized nonlinear governing equation is derived for analyzing the behavior of the shells. The explicit expressions for static and dynamic critical buckling loading are thus developed. To study the dynamic buckling of the shells, the governing equation is examined via a numerical approach implementing the fourth-order Runge-Kutta method. With a procedure presented by Budiansky-Roth, the critical load for dynamic post-buckling is obtained. The effects of various parameters, such as material and geometrical parameters, on the post-buckling behaviors are investigated.

Nonlinear dynamic analysis of spiral stiffened cylindrical shells rested on elastic foundation

Kamran Foroutan,Alireza Shaterzadeh,Habib Ahmadi 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.32 No.4

In this paper, an analytical approach for the free vibration analysis of spiral stiffened functionally graded (SSFG) cylindrical shells is investigated. The SSFG shell is resting on linear and non-linear elastic foundation with damping force. The elastic foundation for the linear model is according to Winkler and Pasternak parameters and for the non-linear model, one cubic term is added. The material constitutive of the stiffeners is continuously changed through the thickness. Using the Galerkin method based on the von Kármán equations and the smeared stiffeners technique, the non-linear vibration problem has been solved. The effects of different geometrical and material parameters on the free vibration response of SSFG cylindrical shells are adopted. The results show that the angles of stiffeners and elastic foundation parameters strongly effect on the natural frequencies of the SSFG cylindrical shell.

Simultaneous resonances of SSMFG cylindrical shells resting on viscoelastic foundations

Kamran Foroutan,Habib Ahmadi 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.37 No.1

The present paper investigates the simultaneous resonance behavior of spiral stiffened multilayer functionally graded (SSMFG) cylindrical shells with internal and external functionally graded stiffeners under the two-term large amplitude excitations. The structure is embedded within a generalized nonlinear viscoelastic foundation which is composed of a two-parameter Winkler-Pasternak foundation augmented by a Kelvin-Voigt viscoelastic model with a nonlinear cubic stiffness. The cylindrical shell has three layers consist of ceramic, FGM, and metal. The exterior layer of the cylindrical shell is rich ceramic while the interior layer is rich metal and the functionally graded material layer is located between these layers. With regard to classical shells theory, von-Kármán equation, and Hook law, the relations of stress-strain are derived for shell and stiffeners. The spiral stiffeners of the cylindrical shell are modeled according to the smeared stiffener technique. According to the Galerkin method, the discretized motion equation is obtained. The simultaneous resonance is obtained using the multiple scales method. Finally, the influences of different material and geometrical parameters on the system resonances are investigated comprehensively.

Asian Migrant Women’s Employment Participation: Patterns, Determinants and Differentials

Yaghoob FOROUTAN,Peter MCDONALD 이화여자대학교 아시아여성학센터 2008 Asian Journal of Women's Studies(AJWS) Vol.14 No.2

This paper is an empirical investigation into Asian migrant women’s employment participation in Australia. Using the customized tabulations from the 2001 Census of Population and Housing, it examines the patterns and determinants of employment status and occupational levels of Asian-born migrant women and compares their differentials with both non-Asian-born migrants and native-born women in the multiethnic and multicultural context of Australia. The status and success of migrant groups in the labor market has been observed to be a key indication of migrants’ settlement in the destination country, while acknowledging issues of selectivity of migration from Asia to Australia as a multicultural context. The multivariate findings of the study provide a basis for settlement assessment of Asian migrant women.

Effects of intraperitoneal injection of magnetic graphene oxide on the improvement of acute liver injury induced by CCl4

Tahereh Foroutan,Fatemeh Ahmadi,Fariborze Moayer,Sahar Khalvati 한국생체재료학회 2020 생체재료학회지 Vol.24 No.3

Background: Liver failure is usually associated with the inflammation and oxidation of hepatocytes. Due to their unique properties, graphene and graphene-based nanostructures such as magnetic graphene oxide (MGO) are useful in biomedicine and engineering. In this study, synthesized MGO was used to improve the liver failure induced by carbon tetrachloride (CCl4). The hepatoprotective effects of intraperitoneal injection of MGO on the rat model of CCl4-induced acute liver failure were investigated. Materials and methods: In order to provide a rat model of acute liver failure, male rats were intraperitoneally injected with 2 ml/kg body weight CCl4. In the experimental groups, rats received 2 ml/kg CCl4 and 300 mg/kg MGO body weight simultaneously. Four days after injection, symptoms of acute liver failure appeared. The control, sham, CCl4, and CCl4 + MGO groups were compared and analyzed both histologically and biochemically. Results: The results indicated that the MGO injection reduced all CCl4-induced liver failure such as necrosis, fibrosis, inflammation, aspartate transaminase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP) in the experimental groups of the rat model of acute liver failure. Conclusion: The hepatoprotective effects of MGO might be due to histopathological suppression and inflammation inhibition in the liver.

Combination resonances of imperfect SSFG cylindrical shells rested on viscoelastic foundations

Kamran Foroutan,Habib Ahmadi 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.75 No.1

The present paper investigates the combination resonance behavior of imperfect spiral stiffened functionally graded (SSFG) cylindrical shells with internal and external functionally graded stiffeners under two-term large amplitude excitations. The structure is embedded within a generalized nonlinear viscoelastic foundation, which is composed of a two-parameter Winkler-Pasternak foundation augmented by a Kelvin-Voigt viscoelastic model with a nonlinear cubic stiffness, to account for the vibration hardening/softening phenomena and damping considerations. With regard to classical plate theory of shells, von-Kármán equation and Hook law, the relations of stress-strain are derived for shell and stiffeners. The spiral stiffeners of the cylindrical shell are modeled according to the smeared stiffener technique. According to the Galerkin method, the discretized motion equation is obtained. The combination resonance is obtained by using the multiple scales method. Finally, the influences of the stiffeners angles, foundation type, the nonlinear elastic foundation coefficients, material distribution, and excitation amplitude on the system resonances are investigated comprehensively.