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A survey was carried out in five provinces of Iran (Kerman, Sistan and Baluchestan, Hormozgan, Khorasan and Yazd) for the presence of Alfalfa mosaic virus (AMV) sero-types in alfalfa during 2002 to 2003. The number of samples collected was 250, represent-ing the diversity and geographical distribution of AMV in these areas. Diagnosis was car-ried out using polyclonal (PAbs) and monoclonal (MAbs) antibodies. A total of 110 symp-tomatic leaf samples gave a positive reaction in ELISA with polyclonal antibodies. Twelve out of 20 MAbs reacted with all samples tested and were considered as non-differentiating MAbs. Only the MAbs-12, 13, 15, 21, 22 and 24 gave a clear differential reaction and were used for identifying AMV serotypes. Two MAbs (1 and 2) did not react with AMV posi-tive samples. Serological relatedness among AMV samples was studied by indicating the existence of six serotypes of AMV strains in the surveyed areas.

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In recent years using steel plate shear wall system, because of its advantages in comparison with other earthquake resistant systems, has been a matter of attention. Some of its advantages relative to other systems include abundance advantage, high ductility, good hysteretic behavior and energy absorption capacity, high stiffness and economic advantages. Regarding that in Iran there is high seismicity risk and the need to strengthen old and unsafe urban textures and buildings, using this system as a lateral load resistant system seems appropriate and economical. In the present research strengthening of x-braced steel frames with steel plate shear walls is evaluated. Addition of bracing to unbraced frame spans, substituting braces with thin steel shear wall panels and adding thin steel shear wall panels to unbraced spans which do not have architectural requirements are considered as retrofitting strategies. The focus is on the methods in which retrofitting is only done by adding steel plate shear wall elements to braced frames. Some of these methods have many economic and practical advantages. Others are only proper for some special cases. In this study a number of x-braced steel frames designed by the first edition of Iranian code of practice for seismic resistant design of buildings (Iranian Standard No. 2800) are taken as basic frames which need to be retrofitted. These basic frames are retrofitted by adding steel panels with different methods. Then nonlinear static analysis (pushover analysis) with displacement control pattern has been done on both basic and retrofitted finite element frame models and the capacity curves (diagram of story displacements against base shear) of basic frames and retrofitted frames are compared. Considering the results of the pushover analysis of models in which seismic retrofitting is done by replacing x-bracing earthquake resistant system with steel plate shear walls and the results of other methods of strengthening, it is seen that seismic behavior of retrofitted frames is more desirable in terms of overstrength factor (Ω) and overall ductility of structure ( ). The failure and fracture mode in most of the medium-rise frames was ductile but in the short-rise frames the fracture was brittle. Thus, replacing the braces in short-rise structure with thin steel shear walls seems irrational and unjustified economically. But it is to be mentioned that strengthening and increasing the moment of inertia of the adjacent columns of steel shear wall panels in structures with brittle fracture mode could result the change from brittle to ductile fracture. The results of this research show that in the case of steel braced frames with regard to some scientific, technical and practical points; replacing concentric steel bracing earthquake resistant system by steel plate shear walls can be used as a suitable method for retrofitting a wide range of existing steel structures in Iran.

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Structural redundancy is a non-independent concept in structural engineering and has inherent dependence on structural parameters such as overstrength and ductility, so that both of overstrength and ductility capacities should change corresponding to any variation in structural redundancy. Nevertheless, most of researchers notified that taking any increase in structural redundancy should be a desirable property to deal with more effectively against earthquake loading. Furthermore, this issue can reduce structural sensitivity to abnormal loads. In this research to clarify the pure role of redundancy in earthquake resistant design and to distinguish the role of redundancy from total overstrength capacity, a number of 3D reinforced concrete special moment resistant frames (RC-SMRF) with equal ultimate base shear coefficient were designed. The dynamic behavior parameters of the designed structures under natural strong ground motion were evaluated, especially with regards to configuration of nonlinear deformations. The analytical outputs obtained from analyzed structures are illustrated ensembles of maximum acceleration, maximum velocity and maximum drift of each story. Furthermore, adequacy and accuracy of response modification factor which should be assigned as general indicator of quality of total seismic behavior has been studied conceptually. The results of this research indicate that: (i) Assigning an increase in structural redundancy would not always lead to efficient improvement in structural seismic behavior. Furthermore, notification to process of increased redundancy should not be consider as a criterion for any basic improvement in structural performance. This issue means that it is better to consider the effects of redundancy on important seismic parameters such as both the structural member ductility and the overstrength capacity. (ii) The calculated response modification factors as mentioned in this research, can consider as an index of quality of structural dynamic performance which is corresponding to a certain level of redundancy. Accordingly, the above statement should be notified in general cases of those earthquake loadings which would cause a certain level of story drift. This certain level of story drift would denote the structural behavior typically follows the calculated response modification factor. Oppositely, if an earthquake loading causes more story drift from that assigned certain level, structural behavior typically does not follow the calculated response modification factor. (iii) The codified procedure of calculation of response modification factor which were discussed and assessed in this study, cannot be realized subjected to those input strong ground motions that able to display high amplitude and long period pulse or pulses in their velocity time history. It is important to know that strong near-fault ground motions often have an impulsive feature and impose large amounts of sudden intense kinematic energy which must be dissipated by structural system during a short period of time. This issue causes amplified deformation demands in structures which are associated with very few cycles of cumulative plastic deformations. Hence, the earthquake damages due to these seismic load cases are effectively related to maximum deformation as well as maximum ductility. Yet, structures cannot accomplish based on the calculated response modification factor in the mentioned cases.

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Alfalfa crops were surveyed for the incidence of alfalfa mosaic virus (AMV), cucumber mosaic virus (CMV), peanut stunt virus (PSV), bean leaf roll virus (BLRV), bean yellow mosaic virus (BYMV) and bean common mosaic virus (BCMV) in the major growing areas in the southeast and central regions of Iran. Samples were collected between May 2009 and March 2011 and analyzed for viral infection initially by enzyme-linked immunosorbent assay (ELISA) followed by RT-PCR using capsid protein gene specific primers. In total, 634 symptomatic leaf samples were collected in four southeastern and central provinces of Iran representing 20 regions. Our results revealed a high incidence of AMV over a wide geographical area. AMV and BLRV were identified in most regions, whereas BYMV was found only in Yazd Province. PSV was detected in three regions, but not in Sistan- Balouchestan and Hormozgan Provinces. The highest incidence of viral infection amongst the surveyed provinces was recorded in Kerman (66.8%), followed by Yazd (39%), Sistan and Balouchestan (20.8 %), and Hormozgan (4.5%). AMV, BLRV, PSV and BYMV were present in 23.3%, 12%, 0.70% and 0.28% of the samples, respectively. CMV and BCMV were not detected in any surveyed region. Multiple virus infections were recorded in 42 samples. This is the first report on the detected occurrence of BLRV, PSV and BYMV in alfalfa in the southeast and central regions of Iran.

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Objective: In this study we introduced an RGD-containing peptide of collagen IV origin that possesses potent cell adhesion and proliferation properties. This peptide was immobilized on a nanofibrous polycaprolactone/gelatin scaffold after which we analyzed human bone marrow-derived mesenchymal stem cells (hBMSCs) adhesion and proliferation on this peptide-modified scaffold. Methods: Nanofibrous scaffold was prepared by electrospinning. The peptide was synthesized by solid-phase peptide synthesis and immobilized on electrospun nanofibrous a polycaprolactone/gelatin scaffold by chemical bonding. Native and modified scaffolds were characterized with Scanning Electron Microscope (SEM) and Fourier-Transform Infra-red Spectroscopy (FTIR). Adhesion and proliferation of hBMSCs on native and modified scaffolds were analyzed by the Methylthiazol Tetrazolium (MTT) assay. Results: SEM images showed that electrospun scaffolds had homogenous morphology and were 312±89 nm in diameter. There was no significant difference in scaffold morphology before and after peptide immobilization. FTIR results showed that the peptide was successfully immobilized on the scaffold. Based on MTT assay, cell adhesion studies indicated that peptide immobilization improved cell adhesion on RGD-modified scaffolds at all corresponding time points (pConclusion: This novel peptide and modified nanofibrous scaffold, having improved cell adhesion and proliferation properties, can be used for tissue engineering and regenerative medicine by using hBMSCs.

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Deccan was under the control of six Muslim ruling dynasties, i.e. the Bahmanîds and their successors from the second half of the eight century to the end of the eleventh century (A.H.). Most of the ruling class, the aristocrats and courtiers in that period were Muslims. But the state particularly villages and small towns were dominated practicing Hindus and they still form the majority in Deccan. Consequently, the Muslims minority had no way but to employ the experienced and capable natives to rule over the Hindus and administer the military and governmental organizations of that vast territory. Moreover, they employed Hindus in large numbers for their military and governmental organizations. Giving Hindus more religious freedom, Muslim dynasties paved the way for their further effective cooperation. The main reliance of the Muslim kings in military affairs was on Maratha tribes and a number of big Maratha families with forces serving them. The financial organizations of these dynasties were mainly controlled by the Brahmans. In addition, the Hindus had a great influence on political issues and the court hence; some of them achieved the highest ranks such as ministerial position (pîshwâ). This article aims at reviewing the role and share of the Hindus in administrating the bodies of the Deccan Muslim governments in three areas of military, finance and politics.

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Accidental fire can be a catastrophe for engineering constructions, especially in building structures. Among structures made of various engineering materials exposed to fire, the reinforced concrete (RC) structures show better performance against fire, due to lower relative thermal conductivity, higher specific heat capacity of concrete, and slower reduction of concrete mechanical characteristics compared with other types of the structure materials. However, in case of severe fire exposure, the RC structures may experience serious structural damage due to the explosive concrete spalling resulting in a high-temperature rise in the reinforcing rebars and relatively large deformation with very limited residual bearing capacity. Although the explosive spalling and significant loss of the cross-sectional area of RC structural elements is a sign of severe damage to these elements, the reduction of mechanical properties of the materials and the performance level of the structure due to chemical reactions such as C-S-H gel dehydration caused by penetration of high temperature in the interior layers of the element cross-section may not be easily visible and evaluated.
A building that has experienced a fire, cannot be exploited for immediate reuse, even when the fire is completely extinguished until load bearing capacity of its members is determined. Therefore, it is necessary to determine the residual capacity of structural elements through logical engineering methods to facilitate the re-operation or development of strengthening methods in the fired RC structures.
Due to the importance of recognizing the behavior and residual seismic capacity of the structures exposed to fire, in this paper, a numerical study based on the nonlinear finite element method has been performed on RC frames. In the first step of the research, the process of heat distribution in the frames located in the furnace based on the previous experimental study is simulated by heat transfer analysis. All three modes of heat transfer including convection, radiation, and conduction were considered in this analysis and the effect of moisture content and emissivity coefficient was evaluated. In the second step, using the residual mechanical properties of materials (reinforcing steel rebar and concrete) based on the maximum heat experienced in the previous step, the seismic behavior of RC frames is evaluated using the pushover analysis. The experimental RC specimens used to validate the proposed numerical model consist of two frames with various beam/column bending capacity ratios in two cases, at room temperature and after being exposed to fire. Due to the different relationships available to determine the residual compressive strength of concrete, the seismic response of the frame was investigated based on three common relations Shi, Lie, and Schneider. The results showed that the proposed numerical analysis method has good accuracy in both steps of analysis and different models for estimating the residual compressive strength, despite some differences, have the ability to predict the post-fire performance of RC frames. It was also shown that for the RC frame specimen with the strong beam-weak column, the ratio of reduced post-fire load bearing capacity and energy absorption is higher.
 

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The evaluation of the fragility functions is an analytical approach that allows different ground motions to be used at varying intensity levels and represent various characteristics of low-intensity and high-intensity shakings. The fragility curves demonstrate the structure’s probability of collapse, or other limit states, as a function of some ground motion intensity measures (IM). The intensity measure is often quantified by spectral acceleration (Sa) or peak ground acceleration (PGA). Based on the statistical procedures, the parameters of the fragility functions are computed by assessing the results of nonlinear dynamic time history analyses. Therefore, the probability of failure associated with a prescribed criterion (e.g. the maximum inter-story drift) is estimated based on the probabilistic distribution relations.
This paper evaluates the effects of internal flexural frames on the seismic performance of diagrid structures based on fragility curves. This evaluation is achieved by designing a group of 24-story studied diagrid models with various diagonal angles of 49, 67, and 74 according to the Iranian Standard No. 2800 (4th edition) and the Iranian National Building Code (Steel Structures-Issue 10). Then, some specific interior gravity frames of the studied diagrid models are replaced with bending frames. The seismic vulnerability of the studied diagrid structures with and without internal bending frames is assessed using nonlinear time history and incremental dynamic analyses (IDA) under near-field earthquake records containing different directivity effects. Finally, the fragility curves for the studied structures were obtained based on the lognormal probabilistic distribution function for the seismic performance limit states including IO, LS, CP, and global instability (GI). Moreover, the seismic performance levels of the studied structures were determined based on the FEMA 356.
The results of performed nonlinear time history analyses indicate that the application of internal bending frames in diagrid structures would reduce the value of inter-story drift in upper floor levels, especially when the angles of exterior diagonal members are large. The results also show that the global instability of diagrid structures without internal bending frames can occur at a faster rate than the skeletal models with internal bents. Also, the contribution of the internal bending frames in improving the nonlinear behavior of diagrid structures depends on the perimeter triangular patterns. Due to this dependency, the increase in the angle of the inclined members in skeletal geometric configuration can increase the effectiveness of the internal bending frames in preventing the occurrence of global dynamic instability. The fragility curves of the studied diagrid structures illustrate that the internal bending frames reduce potentially excessive seismic performance levels. Furthermore, the internal bending frames amplify the seismic energy dissipation capability of the diagrid structures.