Serum Level of Matrix Metalloproteinase-2 and -9 in Patients with Laryngeal Squamous Cell Carcinoma and Clinical Significance

Lotfi, Alireza,Mohammadi, Ghodrat,Saniee, Lale,Mousaviagdas, Mehrnoosh,Chavoshi, Hadi,Tavassoli, Atena Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.15

Background: Laryngeal cancer is an important malignancy in head and neck area and squamous cell carcinoma (SCC) is the most common type accounting for 95% of cases. Increase in matrix metalloproteinases (MMPs) in different tumors and their correlation with tumor invasiveness has been documented. However, most studies have evaluated MMP-2 and MMP-9 expression and few have evaluated serum levels. The aim of current study was to evaluate serum levels in patients with laryngeal SCC compared to normal subjects and assess any relation with tumor clinicopathological findings. Materials and Methods: In this case control study, 20 patients with oral SCC and 20 healthy subjects were included. Serum levels of MMP-2 and MMP-9 were compared between groups and correlations with findings including grade (T) and node involvement (N) were evaluated. Results: Patients with laryngeal SCC had significantly higher serum levels of MMP-2 (p=0.01) and MMP-9 (p=0.03) compared to healthy subjects. Patients with higher T stage (T3,4) had significantly higher MMP-2 (p=0.04) and MMP-9 (p=0.01). There was significant positive correlation between serum levels of MMP-2 with T stage (r=0.45, p=0.04) and lymph node involvement (r=0.563, p=0.01) and between levels of MMP-9 with T stage (r=0.527, p=0.01). Conclusions: Our results showed that compared to healthy subjects, both MMP-2 and MMP-9 are significantly increased in serum of laryngeal SCC cases. MMP-2 was correlated with lymph node involvement while MMP-9 has stronger correlation with T stage compared to MMP-2.

Application of Wavenumber-TD approach for time harmonic analysis of concrete arch dam-reservoir systems

Lotfi, Vahid,Zenz, Gerald Techno-Press 2018 Coupled systems mechanics Vol.7 No.3

The Wavenumber or more accurately Wavenumber-FD approach was initially introduced for two-dimensional dynamic analysis of concrete gravity dam-reservoir systems. The technique was formulated in the context of pure finite element programming in frequency domain. Later on, a variation of the method was proposed which was referred to as Wavenumber-TD approach suitable for time domain type of analysis. Recently, it is also shown that Wavenumber-FD approach may be applied for three-dimensional dynamic analysis of concrete arch dam-reservoir systems. In the present study, application of its variation (i.e., Wavenumber-TD approach) is investigated for three-dimensional problems. The method is initially described. Subsequently, the response of idealized Morrow Point arch dam-reservoir system is obtained by this method and its special cases (i.e., two other well-known absorbing conditions) for time harmonic excitation in stream direction. All results for various considered cases are compared against the exact response for models with different values of normalized reservoir length and reservoir base/sidewalls absorptive conditions.

An efficient three-dimensional fluid hyper-element for dynamic analysis of concrete arch dams

Lotfi, Vahid Techno-Press 2006 Structural Engineering and Mechanics, An Int'l Jou Vol.24 No.6

The accurate dynamic analysis of concrete arch dams relies heavily on employing a three-dimensional semi-infinite fluid element. The usual method for calculating the impedance matrix of this fluid hyper-element is dependent on the solution of a complex eigen-value problem for each frequency. In the present study, an efficient procedure is proposed which simplifies this procedure amazingly, and results in great computational time saving. Moreover, the accuracy of this technique is examined thoroughly and it is concluded that efficient procedure is incredibly accurate under all practical conditions.

Study on the Thermally-Induced Stress and Relaxation of Ceramic Breeder Pebble Beds

Lotfy, Mahmoud,Ying, Alice,Abdou, Mohamed,Park, Yi-Hyun,Cho, Seungyon AMERICAN NUCLEAR SOCIETY, INC. 2017 Fusion science and technology Vol.72 No.3

Understanding the possible underlying mechanisms for low fouling tendency of the forward osmosis and pressure assisted osmosis processes

Lotfi, Fezeh,Chekli, Laura,Phuntsho, Sherub,Hong, Seungkwan,Choi, Joon Young,Shon, Ho Kyong Elsevier Scientific Pub. Co 2017 Desalination Vol. No.

<P><B>Abstract</B></P> <P>We investigated the possible underlying mechanism of the low fouling potential in the forward osmosis (FO) process during the osmotic dilution of seawater as part of the simultaneous desalination and wastewater reuse by FO and reverse osmosis hybrid system. Long-term experiments revealed an interesting water flux pattern highly dependent on the different operating parameters. The most interesting observation made was the spontaneous increase in the FO permeate flux at regular time interval during the FO operation using synthetic wastewater as feed and seawater. This sinusoidal FO flux pattern related well with the build-up of loose fouling layer and their natural peel-off from the membrane surface upon reaching certain layer thickness due to crossflow velocity shear. This flux pattern was more prominent at higher cross-flow velocity rates, lower feed water pH, for a smoother membrane surface and at lower operating pressure during pressure assisted osmosis (PAO) mode. Based on these results, membrane cleaning strategies were proposed by targeting a higher cross-flow velocity shear at a time when the permeate flux started to just increase. The approach of physical membrane cleaning was observed efficient and was able to almost fully restore the initial flux even under the PAO operation at 4bar.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An interesting water flux pattern was observed during osmotic dilution of seawater. </LI> <LI> It was related to the build-up of loose fouling layer peeled-off from the surface. </LI> <LI> This sinusoidal flux pattern was highly dependent on the operating parameters. </LI> <LI> Intrinsic membrane cleaning strategies can be adopted; avoiding plant down time. </LI> <LI> Increasing the feed cross-flow velocity at specific time was found most efficient. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Preface to Festschrift in Wyllis Bandler's Honor

Lotfi Zadeh,Ladislav Kohout,Chris Trayner,Pratit Santiprabhob,Kyung Whan Oh 한국지능시스템학회 1993 한국지능시스템학회논문지 Vol.3 No.1

Serum Levels of MMP9 and MMP2 in Patients with Oral Squamous Cell Carcinoma

Lotfi, Alireza,Mohammadi, Ghodrat,Tavassoli, Atena,mousaviagdas, Mehrnoosh,Chavoshi, Hadi,Saniee, Lale Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.4

Background: Squamous cell carcinoma (SCC) is the most common cancer in the oral area. Matrix metalloproteinases (MMPs) and especially MMP-2 and MMP-9 are increased in malignancy and lymph node involvement in oral SCCs. We aimed to evaluate the serum levels of MMP-2 and MMP-9 in patients with oral SCC compared to normal subjects and their relation with clinicopathological findings. Materials and Methods: In this case control study, 20 patients with oral SCC and 20 healthy subjects were included and serum levels of MMP-2 and MMP-9 were compared between groups. Also, the correlation between these markers with clinicopathological findings including grade (T) and node (N) were evaluated. Results: Patients with oral SCC had significantly higher serum levels of MMP-2 (p=0.01) and MMP-9 (p<0.001) compared to healthy subjects. With increase in grade T, MMP-2 was significantly increased (p=0.001), but in the MMP-9 case this was not significant (p=0.27). The levels of MMP-2 (p=0.002) and MMP-9 (p=0.01) in cases with lymph node involvement and that of MMP-2 in subjects with smoking history (p=0.001) were significantly high. There was significantly positive correlation between MMP-2 with grade T tumor (r=0.598, p=0.005), lymph node involvement (r=0.737, p<0.001) and smoking (r=0.674, p=0.001) and also between MMP-9 and lymph node involvement (r=0.474, p=0.03). Conclusions: Both markers are significantly increased in oral SCC compared to healthy subjects. However, MMP-2 was better for evaluating lymph node involvement and tumor grade.

Numerical Investigation of CuO-Water Nanofluid Flow and Heat Transfer across a Heated Square Cylinder

Lotfi Bouazizi,Said Turki 한국유체기계학회 2016 International journal of fluid machinery and syste Vol.9 No.4

Flow over a bluff body is an attractive research field in thermal engineering. In the present study, laminar flow over a confined heated square cylinder using CuO-Water nanofluid is considered. Unsteady two-dimensional Navier-Stokes and energy equations are solved numerically using finite volume method (FVM). Recent correlations for the thermal conductivity and viscosity of nanofluids, which are function of nanoparticle volume fraction, temperature and nanoparticle diameter, have been employed. The results of numerical solution are obtained for Richardson number, nanoparticle volume fractions and nanoparticle diameters ranges of 0-1, 1-5% and 30-100 nm respectively for a fixed Reynolds number of Re = 150. At a given volume concentration, the investigations reveal that the decreasing in size of nanoparticles produces an increase in heat transfer rates from the square cylinder and a decrease in amplitude of the lift coefficient. Also, the increment of Nusselt number is more pronounced at higher concentrations and higher Richardson numbers.

Blast behavior of steel infill panels with various thickness and stiffener arrangement

Lotfi, Saeid,Zahrai, Seyed Mehdi Techno-Press 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.65 No.5

Infill panel is the first element of a building subjected to blast loading activating its out-of-plane behavior. If the infill panel does not have enough ductility against the loading, it breaks and gets damaged before load transfer and energy dissipation. As steel infill panel has appropriate ductility before fracture, it can be used as an alternative to typical infill panels under blast loading. Also, it plays a pivotal role in maintaining sensitive main parts against blast loading. Concerning enough ductility of the infill panel out-of-plane behavior, the impact force enters the horizontal diaphragm and is distributed among the lateral elements. This article investigates the behavior of steel infill panels with different thicknesses and stiffeners. In order to precisely study steel infill panels, different ranges of blast loading are used and maximum displacement of steel infill under such various blast loading is studied. In this research, finite element analyses including geometric and material nonlinearities are used for optimization of the steel plate thickness and stiffener arrangement to obtain more efficient design for its better out-of-plane behavior. The results indicate that this type of infill with out-of-plane behavior shows a proper ductility especially in severe blast loadings. In the blasts with high intensity, maximum displacement of infill is more sensitive to change in the thickness of plate rather the change in number of stiffeners such that increasing the number of stiffeners and the plate thickness of infill panel would decrease energy dissipation by 20 and 77% respectively. The ductile behavior of steel infill panels shows that using infill panels with less thickness has more effect on energy dissipation. According to this study, the infill panel with 5 mm thickness works better if the criterion of steel infill panel design is the reduction of transmitted impulse to main structure. For example in steel infill panels with 5 stiffeners and blast loading with the reflected pressure of 375 kPa and duration of 50 milliseconds, the transmitted impulse has decreased from 41206 N.Sec in 20 mm infill to 37898 N.Sec in 5 mm infill panel.

Direct frequency domain analysis of concrete arch dams based on FE-BE procedure

Lotfi, Vahid Techno-Press 2007 Structural Engineering and Mechanics, An Int'l Jou Vol.26 No.4

A FE-BE procedure is presented for dynamic analysis of concrete arch dams. In this technique, dam body is discretized by finite elements, while foundation rock is handled by three dimensional boundary element formulation. This would allow a rigorous inclusion of dam-foundation rock interaction, with no limitations imposed on geometry of canyon shape. Based on this method, a previously developed program is modified, and the response of Morrow Point arch dam is studied for various ratios of foundation rock to dam concrete elastic moduli under an empty reservoir condition. Furthermore, the effects of canyon shape on response of dam, is also discussed.