Dietary Antioxidant Intake in Relation to Semen Quality Parameters in Infertile Men: a Cross-Sectional Study

( Mehran Rahimlou ),( Sara Sohaei ),( Mohammadhossein Nasr-esfahani ),( Mehran Nouri ) 한국임상영양학회 2019 Clinical Nutrition Research Vol.8 No.3

The objective of this study was to assess the association between dietary antioxidant intake and semen quality parameters in infertile men. In this cross-sectional study, dietary antioxidant intake was evaluated in 175 infertile Iranian men by a validated dish-based 106-item semi-quantitative food frequency questionnaire. Men were asked to abstain from ejaculation for at least 72 hours before sample collection. Semen parameters were assessed by a sperm counting chamber and Terminal deoxynucleotidyl transferase dUTP nick end labeling assay methods. Linear quantile regression was used to determine the associations between antioxidant nutrient intake and semen quality parameters (including total sperm count, sperm density, total motility, DNA damage and DNA fragmentation). Mean age of study participants was 32.19 ± 2.34 years. Compared with the lowest quartile, men in the highest quartile of dietary β-carotene and vitamin C intake had lower sperm DNA fragmentation index (P_trend = 0.042 and P_trend = 0.03, respectively). Also, dietary intake of beta-cryptoxanthin had a positive association with sperm density (P_trend = 0.02), and dietary lutein was associated with total sperm count (P_trend = 0.045). Dietary intake of other antioxidants did not significantly correlate with the indicators related to the quantity and quality of sperm (p > 0.05). These data suggest that dietary intake of some of the antioxidants is associated with semen related parameters.

Nonlinear vibration of Euler-Bernoulli beams resting on linear elastic foundation

Mehran Javanmard,Mahdi Bayat,Alireza Ardakani 국제구조공학회 2013 Steel and Composite Structures, An International J Vol.15 No.4

In this study simply supported nonlinear Euler-Bernoulli beams resting on linear elasticfoundation and subjected to the axial loads is investigated. A new kind of analytical technique for anon-linear problem called He’s Energy Balance Method (EBM) is used to obtain the analytical solution fornon-linear vibration behavior of the problem. Analytical expressions for geometrically non-linear vibrationof Euler-Bernoulli beams resting on linear elastic foundation and subjected to the axial loads are provided. The effect of vibration amplitude on the non-linear frequency and buckling load is discussed. The variationof different parameter to the nonlinear frequency is considered completely in this study. The nonlinearvibration equation is analyzed numerically using Runge-Kutta 4th technique. Comparison of Energy BalanceMethod (EBM) with Runge-Kutta 4th leads to highly accurate solutions.

A new look at the restrictions on the speed and magnitude of train loads for bridge management

Mehran Aflatooni,Tommy H.T. Chan,David P. Thambiratnam 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.53 No.1

In current bridge management systems (BMSs), load and speed restrictions are applied onunhealthy bridges to keep the structure safe and serviceable for as long as possible. But the question is, whether applying these restrictions will always decrease the internal forces in critical components of thebridge and enhance the safety of the unhealthy bridges. To find the answer, this paper for the first time in literature, looks into the design aspects through studying the changes in demand by capacity ratios of the critical components of a bridge under the train loads. For this purpose, a structural model of a simply supported bridge, whose dynamic behaviour is similar to a group of real railway bridges, is developed. Demand by capacity ratios of the critical components of the bridge are calculated, to identify their sensitivity to increase of speed and magnitude of live load. The outcomes of this study are very significant as they show that, on the contrary to what is expected, by applying restriction on speed, the demand by capacity ratio of components may increase and make the bridge unsafe for carrying live load. Suggestions are made to solve the problem.

Long-term performance degradation study of solid oxide carbon fuel cells integrated with a steam gasifier

Mehran, M.T.,Lim, T.H.,Lee, S.B.,Lee, J.W.,Park, S.J.,Song, R.H. Pergamon Press 2016 ENERGY Vol.113 No.-

We investigated the long-term performance degradation in a solid oxide carbon fuel cell (SO-CFC) integrated with a steam gasifier that used activated carbon as a fuel. The steam gasifier-integrated SO-CFC was continuously operated for 2000 h at 750 <SUP>o</SUP>C under galvanostatic conditions. Fuel analysis, in-situ electrochemical tests, and post-mortem characterization were performed to determine the dominant degradation factors during the extended operation of the SO-CFC. During the 2000 h continuous operation, the overall degradation rate of the SO-CFC was 0.108 V per 1000 h. Electrochemical impedance spectroscopy analysis showed that the polarization and ohmic resistance of the SO-CFC increased gradually with the operation time. The post-mortem diagnosis via SEM, XRD, EDS, and XPS analyses revealed that the increased Ni particle coarsening and carbon deposition at the anode functional layer induced increased performance degradation in the SO-CFC. The long-term durability study of the SO-CFC with a steam gasifier confirmed that conventional anode materials result in rapid performance degradation during 2000 h continuous operation, and further development of anode materials will be necessary for the long and durable operation of SO-CFCs.

POSTERS / PT-074 : INVOLVEMENT OF PROTEIN COMPONENTS OF BRUSH BORDER MEMBRANE IN ITS ADSORPTIVE IMMOBILIZATION TO HYDROPHOBIC SUPPORTS

(Mehran Habibi Rezaei),(Mohsen Nemat Gorgani) 한국생화학분자생물학회 (구 한국생화학회) 1999 6th IUBMB SEOUL CONFERENCE Vol.- No.-

{$L_k$}-biharmonic hypersurfaces in space forms with three distinct principal curvatures

Mehran Aminian 대한수학회 2020 대한수학회논문집 Vol.35 No.4

In this paper we consider $ L_k $-conjecture introduced in \cite{AminianKashani, AminKashani} for hypersurface $ M^n $ in space form $ R^{n+1}(c) $ with three principal curvatures. When $ c=0, -1 $, we show that every $ L_1 $-biharmonic hypersurface with three principal curvatures and $ H_1 $ is constant, has $ H_2=0 $ and at least one of the multiplicities of principal curvatures is one, where $ H_1 $ and $ H_2 $ are first and second mean curvature of $ M $ and we show that there is not $ L_2 $-biharmonic hypersurface with three disjoint principal curvatures and, $ H_1 $ and $ H_2 $ is constant. For $ c=1 $, by considering having three principal curvatures, we classify $L_1$-biharmonic hypersurfaces with multiplicities greater than one, $ H_1 $ is constant and $ H_2=0 $, proper $L_1$-biharmonic hypersurfaces which $ H_1 $ is constant, and $ L_2 $-biharmonic hypersurfaces which $ H_1 $ and $ H_2 $ is constant.

Improving sulfur tolerance of Ni-YSZ anodes of solid oxide fuel cells by optimization of microstructure and operating conditions

Mehran, Muhammad Taqi,Khan, Muhammad Zubair,Lee, Seung-Bok,Lim, Tak-Hyoung,Park, Sam,Song, Rak-Hyun Elsevier 2018 International journal of hydrogen energy Vol.43 No.24

<P><B>Abstract</B></P> <P>In this study, we propose an improvement in the sulfur tolerance of nickel-yttria stabilized zirconia (Ni-YSZ) anodes for solid oxide fuel cells (SOFCs) by simultaneously employing optimized operating conditions and microstructural modifications. An electrolyte supported SOFC is operated at 20 ppm H<SUB>2</SUB>S impurity at 750 °C for 20 h degradation and 10 h recovery test. The current cycles with a higher amplitude and small pulse time during the constant current operation are beneficial for the mitigation of sulfur poisoning. The effect of humidity on the sulfur degradation of Ni-YSZ anode is also studied. The synergetic effect of microstructure modification and current cycling conditions improves the sulfur tolerance of Ni-YSZ anode. It has been found that, when an anode with a modified microstructure by infiltrated CeO<SUB>2</SUB> and Yb<SUB>2</SUB>O<SUB>3</SUB> nanoparticles is operated on 20 ppm H<SUB>2</SUB>S poisoned gas at 10% relative humidity and the optimum pulsed current cycling conditions, about 7 times less degradation of the SOFC performance is observed. This study shows that at lower H<SUB>2</SUB>S concentration, a stable operation of a SOFC with minimum degradation can be achieved with the combination of optimization of operating conditions and modification of the anode microstructure.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Sulfur tolerance of Ni-YSZ anodes improved by a novel method. </LI> <LI> Pulsed current cycles at specific intervals regenerates sulfur poisoned Ni in anode. </LI> <LI> Uniform surface modification of anode by infiltration of CeO<SUB>2</SUB> Yb<SUB>2</SUB>O<SUB>3</SUB> nano-particles. </LI> <LI> Optimized conditions show 7 times improvement in sulfur tolerance of Ni-YSZ anodes. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

A new moving-mesh Finite Volume Method for the efficient solution of two-dimensional neutron diffusion equation using gradient variations of reactor power

Mehran Vagheian,Dariush Rezaei Ochbelagh,Morteza Gharib 한국원자력학회 2019 Nuclear Engineering and Technology Vol.51 No.5

A new moving-mesh Finite Volume Method (FVM) for the efficient solution of the two-dimensionalneutron diffusion equation is introduced. Many other moving-mesh methods developed to solve theneutron diffusion problems use a relatively large number of sophisticated mathematical equations, andso suffer from a significant complexity of mathematical calculations. In this study, the proposed methodis formulated based on simple mathematical algebraic equations that enable an efficient mesh movementand CV deformation for using in practical nuclear reactor applications. Accordingly, a computationalframework relying on a new moving-mesh FVM is introduced to efficiently distribute the meshesand deform the CVs in regions with high gradient variations of reactor power. These regions of interestare very important in the neutronic assessment of the nuclear reactors and accordingly, a higher accuracyof the power densities is required to be obtained. The accuracy, execution time and finally visual comparison of the proposed method comprehensivelyinvestigated and discussed for three different benchmark problems. The results all indicated a higheraccuracy of the proposed method in comparison with the conventional fixed-mesh FVM.

Automated segmentation of concrete images into microstructures: A comparative study

Mehran Yazdi,Katayoon Sarafrazi 사단법인 한국계산역학회 2014 Computers and Concrete, An International Journal Vol.14 No.3

Concrete is an important material in most of civil constructions. Many properties of concrete can be determined through analysis of concrete images. Image segmentation is the first step for the most of these analyses. An automated system for segmentation of concrete images into microstructures using texture analysis is proposed. The performance of five different classifiers has been evaluated and the results show that using an Artificial Neural Network classifier is the best choice for an automatic image segmentation of concrete.

Computational Lagrangian Multiplier Method by using for optimization and sensitivity analysis of rectangular reinforced concrete beams

Mehran Shariat,Mahdi Shariati,Amirhossein Madadi,Karzan Wakil 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.29 No.2

This study conducts an optimization and sensitivity analysis on rectangular reinforced concrete (RC) beam using Lagrangian Multiplier Method (LMM) as programming optimization computer soft ware. The analysis is conducted to obtain the minimum design cost for both singly and doubly RC beams according to the specifications of three regulations of American concrete institute (ACI), British regulation (BS), and Iranian concrete regulation (ICS). Moreover, a sensitivity analysis on cost is performed with respect to the effective parameters such as length, width, and depth of beam, and area of reinforcement. Accordingly, various curves are developed to be feasibly utilized in design of RC beams. Numerical examples are also represented to better illustrate the design steps. The results indicate that instead of complex optimization relationships, the LMM can be used to minimize the cost of singly and doubly reinforced beams with different boundary conditions. The results of the sensitivity analysis on LMM indicate that each regulation can provide the most optimal values at specific situations. Therefore, using the graphs proposed for different design conditions can effectively help the designer (without necessity of primary optimization knowledge) choose the best regulation and values of design parameters.