Evaluation of the Analgesic Effect of Dextromethorphan and its Interaction With Nitric Oxide on Sciatic Nerve Ligated Rats

Gholamreza Karimi,Kaveh Tabrizian,Ramin Rezaee 사단법인약침학회 2010 Journal of Acupuncture & Meridian Studies Vol.3 No.1

The symptoms of neuropathic pain are often intractable because they are poorly relieved by conventional analgesics. This therapeutic area remains one of the least satisfactorily managed by current drugs. Effective therapy for this type of pain is lacking, and the underlying mechanisms are poorly understood. The present study was undertaken to determine the effect of sciatic nerve ligation on inducing neuropathic pain and to understand the mechanisms involved, and the effect of, an L-nitro-arginine methyl ester (L-NAME)/dextromethorphan combination therapy on reducing neuropathic pain. According to our results, L-NAME and dextromethorphan showed analgesic properties, but only 100 mg/kg L-NAME had an additive effect on the analgesic effects of dextromethorphan. Our observations support the idea that N-methyl-D-aspartate/nitric oxide pathways play an important role in the development of such sciatic nerve ligated-evoked pathological pain conditions, thus this combination therapy could be used instead of conventional treatment.

Response modification factor of suspended zipper braced frames

Gholamreza Abdollahzadeh,Mehdi Abbasi 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.18 No.1

The suspended zipper bracing system is suggested to reduce the flaws of ordinary zipper braced and concentric inverted V braced frames. In the design procedure of suspended zipper bracing systems, columns and top story truss elements are strengthened. This bracing system show different performances and characteristics compared with inverted V braced and ordinary zipper frames. As a result, a different response modification factor for suspend zipper frames is needed. In this research paper, the response modification factor of suspended zipper frames was obtained using the incremental dynamic analysis. Suspended zipper braced frames with different stories and bay lengths were selected to be representations of the design space. To analyze the frames, a number of models were constructed and calibrated using experimental data. These archetype models were subjected to 44 earthquake records of the FEMA-P695 project data set. The incremental dynamic analysis and elastic dynamic analysis were carried out to determine the yield base shear value and elastic base shear value of archetype models using the OpenSEES software. The seismic response modification factor for each frame was calculated separately and the values of 9.5 and 13.6 were recommended for ultimate limit state and allowable stress design methods, respectively.

Dynamic instability and free vibration behavior of three-layered soft-cored sandwich beams on nonlinear elastic foundations

Gholamreza Asgari,Gholamhassan Payganeh,Keramat Malekzadeh Fard 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.72 No.4

The purpose of the present work was to study the dynamic instability of a three-layered, symmetric sandwich beam subjected to a periodic axial load resting on nonlinear elastic foundation. A higher-order theory was used for analysis of sandwich beams with soft core on elastic foundations. In the higher-order theory, the Reddy's third-order theory was used for the face sheets and quadratic and cubic functions were assumed for transverse and in-plane displacements of the core, respectively. The elastic foundation was modeled as nonlinear’s type. The dynamic instability regions and free vibration were investigated for simply supported conditions by Bolotin’s method. The results showed that the responses of the dynamic instability of the system were influenced by the excitation frequency, the coefficients of foundation, the core thickness, the dynamic and static load factor. Comparison of the present results with the published results in the literature for the special case confirmed the accuracy of the proposed theory.

An Investigation into the Effects of Osteocytes Density and Mechanosensitivity on Trabecular Bone Loss in Aging and Osteoporotic Individuals

Gholamreza Rouhi,Ali Vahdati,Xianjie Li,Les Jozef Sudak 대한의용생체공학회 2015 Biomedical Engineering Letters (BMEL) Vol.5 No.4

Purpose Optimal bone remodeling is responsible for bonehealth and strength, and an imbalance in this process maycause diseases such as osteoporosis. Both osteocyte densityand mechanosensitivity are effective parameters in changingbone apparent density. This study aimed at investigating theeffects of osteocyte density in healthy adults, and osteocytemechanosensitivity in osteoporotic bones, on bone loss usinga semi-mechanistic bone remodeling theory. Methods A 2-D finite element model of trabecular bone wasdeveloped in order to simulate the process of boneremodeling. The structure was loaded by a sinusoidal stress,cycling between 0 and 2 MPa, and at frequency of 1 Hz. Itwas assumed that the stimulus sensed by osteocytes is themaximal strain energy density rate. By changing osteocytedensity and mechanosensitivity, the effects of alteringexternal load magnitude and/or direction were investigated. Results First, trabecular-like structures were obtained fromthe initial configuration, in which trabeculae were lined upwith the loading direction as verification of model’simplementation. Secondly, it was demonstrated that boneloss could occur in healthy older trabecular bone model,compared to healthy young bone model. Finally, this in silicostudy showed that by decreasing osteocyte mechanosensitivity,assuming a constant osteocyte density, a decrease in boneapparent density is predicted. Conclusions Results of this work indicated that the semimechanisticmodel used here may reasonably explain boneloss in healthy adults and in osteoporotic patients. Moreover,this study sheds more light on the possible effects that osteocytedensity in healthy adults, and osteocyte mechanosensitivityin osteoporotic individuals, may have on bone apparentdensity predictions.

Predicting PM2.5 Concentrations Using Artificial Neural Networks and Markov Chain, a Case Study Karaj City

Gholamreza Asadollahfardi,Hossein Zangooei,Shiva Homayoun Aria 한국대기환경학회 2016 Asian Journal of Atmospheric Environment (AJAE) Vol.10 No.2

The forecasting of air pollution is an important and popular topic in environmental engineering. Due to health impacts caused by unacceptable particulate matter (PM) levels, it has become one of the greatest concerns in metropolitan cities like Karaj City in Iran. In this study, the concentration of PM2.5 was predicted by applying a multilayer percepteron (MLP) neural network, a radial basis function (RBF) neural network and a Markov chain model. Two months of hourly data including temperature, NO, NO2, NOx, CO, SO2 and PM10 were used as inputs to the artificial neural networks. From 1,488 data, 1,300 of data was used to train the models and the rest of the data were applied to test the models. The results of using artificial neural networks indicated that the models performed well in predicting PM2.5 concentrations. The application of a Markov chain described the probable occurrences of unhealthy hours. The MLP neural network with two hidden layers including 19 neurons in the first layer and 16 neurons in the second layer provided the best results. The coefficient of determination (R2), Index of Agreement (IA) and Efficiency (E) between the observed and the predicted data using an MLP neural network were 0.92, 0.93 and 0.981, respectively. In the MLP neural network, the MBE was 0.0546 which indicates the adequacy of the model. In the RBF neural network, increasing the number of neurons to 1,488 caused the RMSE to decline from 7.88 to 0.00 and caused R2 to reach 0.93. In the Markov chain model the absolute error was 0.014 which indicated an acceptable accuracy and precision. We concluded the probability of occurrence state duration and transition of PM2.5 pollution is predictable using a Markov chain method.

Retrofitting of Steel Moment-Resisting Frames under Fire Loading against Progressive Collapse

Gholamreza Abdollahzadeh,Reza Shalikar 한국강구조학회 2017 International Journal of Steel Structures Vol.17 No.4

Generally, fire has been one of the most important threats which can lead to the collapse of structures. Due to the high temperature caused by fire, material strength decrease significantly and finally, could lead to failure of different members of a structure. When some parts of the structure are damaged, frames without sufficient resistance and ductility can progressively collapse. In this study, the retrofitting effect of a Steel Moment-Resisting Frame (MRFs) with X and inverted-V braces are investigated using dynamic explicit analysis for frames which had previously suffer progressive collapse under fire. Simultaneously, different bracing systems and fire conditions have been used. Furthermore, the effect of stiffness and strength of bracing systems were numerically analyzed. Studies show that the unbraced moment-resisting frame (MRF) lacks an effective mechanism for transferring loads from failed parts to the neighboring parts and the frame completely collapse due to the catenary actions under fire loading in central span. Systems braced with hat truss, due to their distance from the heated columns, have limited capacity to prevent the pull-in of columns in the heated floor. However, they can directly re-distribute vertical loads which are shed by buckled columns to the neighboring columns. But, their performance in central span fire scenario seems relatively better than edge span fire scenario. On the other hand, vertical bracing systems have a good effect and with restraining the columns, it can prevent them from pull-in. Also, they are able to effectively prevent the global collapse process. Furthermore, the stronger vertical bracing system can decrease the vertical movement of the heated columns and thus, enhance the re-distribution capacity of the frame. Accordingly, with combination of hat truss bracing system and vertical bracing system, new paths can be generated for redistribution of the forces which are shed by failed columns in the frame. At the end, comparing between X bracing systems and inverted-V bracing systems indicates that the frames with inverted-V bracing systems show more ductility.

Image Super Resolution Based on Interpolation of Wavelet Domain High Frequency Subbands and the Spatial Domain Input Image

Gholamreza Anbarjafari,Hasan Demirel 한국전자통신연구원 2010 ETRI Journal Vol.32 No.3

In this paper, we propose a new super-resolution technique based on interpolation of the high-frequency subband images obtained by discrete wavelet transform (DWT) and the input image. The proposed technique uses DWT to decompose an image into different subband images. Then the high-frequency subband images and the input low-resolution image have been interpolated, followed by combining all these images to generate a new super-resolved image by using inverse DWT. The proposed technique has been tested on Lena, Elaine, Pepper, and Baboon. The quantitative peak signal-to-noise ratio (PSNR) and visual results show the superiority of the proposed technique over the conventional and state-of-art image resolution enhancement techniques. For Lena’s image, the PSNR is 7.93 dB higher than the bicubic interpolation.

Cyclic behavior of DCFP isolators with elliptical surfaces and different frictions

Gholamreza Abdollahzadeh,Reza Darvishi 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.64 No.6

Friction Pendulum isolators are tools developed in the past few decades. The simplest form of these isolators, are FPS whose main disadvantages are having a constant frequency independent of the frequency of the structure. For this reason, researchers have invented VFPI isolator whose frequency is variable and depends on displacement. Another friction pendulum isolator is DCFP isolator which is a combination of two FPS isolators. In this article, first by changing the geometry of DCFP isolator plates from spherical to elliptical, the motion and frequency equations of DVFPI isolators are defined, and then the seismic behavior of DVFPI isolators are analyzed in various geometric and plate friction settings using motion equations, and confirmed using ABAQUS software. The most important results of this study are that the hysteresis behavior of DVFPI isolators are severely nonlinear, its curve follows two distinct curvatures, and that the restoring force is faced with softening mechanism that limits the seismic force transmitted to the structure, whereas the restoring force in DCFP isolators increases linearly with increasing displacement.

Damage Evaluation of Reinforced Concrete and Steel Frames under Critical Successive Scenarios

Gholamreza Ghodrati Amiri,Elham Rajabi 한국강구조학회 2017 International Journal of Steel Structures Vol.17 No.4

This paper compares the vulnerability of initial shock-damage reinforced concrete (RC) with steel frames in successive scenarios, as an essential part of developing a framework to consider seismic sequence hazard into structural design. For this, two sets of regular RC and steel moment resisting frames with 3, 5, 7, 10, 12 and 15 stories, are designed and analyzed under two different databases with/without seismic sequences in OpenSees software.The damage states of the model frames were then measured by the Park and Ang’s damage index. From the results of this investigation, it is observed that only considering the mainshock will underestimate the seismic risk in both sets of RC and steel frames. The results of damage evaluation also reveal that RC frames have better performance than steel frames in seismic sequence phenomena. Furthermore, steel frames damage is about 53% more than the damage caused by RC frames under critical successive earthquakes

Isolation, Characterization, and Investigation of Surface andHemolytic Activities of a Lipopeptide Biosurfactant Producedby Bacillus subtilis ATCC 6633

Gholamreza Dehghan-Noudeh,Mohammadreza Housaindokht,Bibi Sedigeh Fazly Bazzaz 한국미생물학회 2005 The journal of microbiology Vol.43 No.3

Bacillus subtilis ATCC 6633 was grown in BHIB medium supplemented with Mn2+ for 96 h at 37oC in a shaker incubator. After removing the microbial biomass, a lipopeptide biosurfactant was extracted from the supernatant. Its structure was established by chemical and spectroscopy methods. The structure was confirmed by physical properties, such as Hydrophile-Lipophile Balance (HLB), surface activity and erythrocyte hemolytic capacity. The critical micelle concentration (cmc) and erythrocyte hemolytic capacity of the biosurfactant were compared to those of surfactants such as SDS, BC (benzalkonium chloride), TTAB tetradecyltrimethylammonium bromide) and HTAB(hexadecyltrimethylammonium bromide). The maximum hemolytic effect for all surfactants mentioned was observed at concentrations above cmc. The maximum hemolytic effect of synthetic surfactants was more than that of the biosurfactant produced by B. subtilis ATCC 6633. Therefore, biosurfactant would be considered a suitable surface-active agent due to low toxicity to the membrane.