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Nikkhoo, Ali,Asili, Soheil,Sadigh, Shabnam,Hajirasouliha, Iman,Karegar, Hossein Techno-Press 2019 Advances in computational design Vol.4 No.3
A low computational cost semi-analytical method is developed, based on eigenfunction expansion, to study the vibration of rectangular plates subjected to a series of moving sprung masses, representing a bridge deck under multiple vehicle or train moving loads. The dynamic effects of the suspension system are taken into account by using flexible connections between the moving masses and the base structure. The accuracy of the proposed method in predicting the dynamic response of a rectangular plate subjected to a series of moving sprung masses is demonstrated compared to the conventional rigid moving mass models. It is shown that the proposed method can considerably improve the computational efficiency of the conventional methods by eliminating a large number of time-varying components in the coupled Ordinary Differential Equations (ODEs) matrices. The dynamic behaviour of the system is then investigated by performing a comprehensive parametric study on the Dynamic Amplification Factor (DAF) of the moving loads using different design parameters. The results indicate that ignoring the flexibility of the suspension system in both moving force and moving mass models may lead to substantially underestimated DAF predictions and therefore unsafe design solutions. This highlights the significance of taking into account the stiffness of the suspension system for accurate estimation of the plate maximum dynamic response in practical applications.
Mohsenian, Vahid,Nikkhoo, Ali Techno-Press 2019 Advances in concrete construction Vol.7 No.3
Irregular distribution of mass in elevation is regarded as a structural irregularity by which the modes with high energy levels are excited and in addition, it can lead the structure to withstanding concentration of nonlinear deformations and consequently, suffer from unpredictable local or global damages. Accordingly, with respect to the lack of knowledge and insight towards the performance of concrete buildings making use of tunnel-form structural system in seismic events, it is of utmost significance to assess seismic vulnerability of such structures involved in vertical mass irregularity. To resolve such a crucial drawback, this papers aims to seismically assess vulnerability of RC tunnel-form buildings considering effects of irregular mass distribution. The results indicate that modal responses are not affected by building's height and patterns of mass distribution in elevation. Moreover, there was no considerable effect observed on the performance levels under DBE and MCE hazard scenarios within different patterns of irregular mass distribution. In conclusion, it appears that necessarily of vertical regularity for tunnel-form buildings, is somehow drastic and conservative at least for the buildings and irregularity patterns studied herein.
Hypercalciuria and febrile convulsion in children under 5 years old
Vahid Seddighi Gorabi,Bahram Nikkhoo,Obeidollah Faraji,Mona Mohammadkhani,Sattar Mirzaee,Mohammad Aziz Rasouli,Abdorrahim Afkhamzadeh 대한소아청소년과학회 2018 Clinical and Experimental Pediatrics (CEP) Vol.61 No.4
Purpose: The association between hypercalciuria and febrile convulsion is controversial. The present study aimed to investigate the statistical association between hypercalciuria and childhood febrile convulsions. Methods: Overall, 160 children aged 6 months to 5 years, including 80 children with febrile convulsion and 80 febrile children without convulsion (comparison group), were recruited. All laboratory tests, including 24-hour urine calcium, were undertaken in an academic clinical laboratory. Results: Forty-five children of the febrile convulsion group (60%) and 30 of the comparison group (40%) had hypercalciuria. There was a significant difference between the 2 groups (P=0.02). Conclusion: Our results indicated that there is a statistical association between convulsion and hypercalciuria in children. Since we found this association with a cross-sectional assessment, further studies, especially prospective and controlled designs, are needed.
Vahid Mohsenian,Ali Nikkhoo 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.69 No.6
Investigations on seismic performance of eccentrically braced frames equipped with dual vertical links have received little attention. Therefore, the main goal of this paper is to describe design steps for such frames and evaluate nonlinear performance of this system according to the reliability analysis. In this study, four and eight story frame structures are analyzed and the response modification factors for different intensity and damage levels are derived in a matrix form based on a new approach. According to the obtained results, the system has high ductility and acceptable seismic performance. Moreover, it is concluded that using response modification factor equal to 8 in the design of system provides desirable seismic reliability under the design and maximum probable hazard levels. Due to desirable performance and significant advantages of the dual vertical links, this system can be used as a main lateral load bearing system, in addition to its application for rehabilitation of damaged structures.
No Significant Association between Human Papillomavirus and Breast Cancer, Sanandaj, Iran
Karimi, Maryam,Khodabandehloo, Mazaher,Nikkhoo, Bahram,Ghaderi, Ebrahim Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.10
Background and Objective: Any role of human papillomavirus (HPV) in the development of breast cancer is conjectural. The aim of this study was to investigate possible links between HPV and breast cancer in women, Sanandaj, Iran. Methods: In this case-control study, 70 formalin fixed and paraffin embedded blocks of breast malignant tumors as a case group and 70 blocks of lesions without malignancy were selected as controls. Sections about $10{\mu}m$ thick were prepared. After removing the paraffin, DNA was extracted. Samples were tested by PCR using general and high-risk specific HPV primers. Results: All 70 malignant breast tumors (cases) were invasive ductal carcinomas, and of the 70 controls, 17 (24.3%) were fibrocystic tumors and 53 (75.7%) fibroadenomas. The age range of women in the case group was 25-72 years old and in the control group It was13-66 years. Using HPV general primers two samples were positive in the case group, confirmed to be HPV-18 using high-risk specific primers. Conclusion: No statistically significant association was found between breast cancer and HPV. It is necessary to confirm this result by further investigations in other populations.
Hypercalciuria and febrile convulsion in children under 5 years old
Gorabi, Vahid Seddighi,Nikkhoo, Bahram,Faraji, Obeidollah,Mohammadkhani, Mona,Mirzaee, Sattar,Rasouli, Mohammad Aziz,Afkhamzadeh, Abdorrahim The Korean Pediatric Society 2018 Clinical and Experimental Pediatrics (CEP) Vol.61 No.4
Purpose: The association between hypercalciuria and febrile convulsion is controversial. The present study aimed to investigate the statistical association between hypercalciuria and childhood febrile convulsions. Methods: Overall, 160 children aged 6 months to 5 years, including 80 children with febrile convulsion and 80 febrile children without convulsion (comparison group), were recruited. All laboratory tests, including 24-hour urine calcium, were undertaken in an academic clinical laboratory. Results: Forty-five children of the febrile convulsion group (60%) and 30 of the comparison group (40%) had hypercalciuria. There was a significant difference between the 2 groups (P=0.02). Conclusion: Our results indicated that there is a statistical association between convulsion and hypercalciuria in children. Since we found this association with a cross-sectional assessment, further studies, especially prospective and controlled designs, are needed.
Lateral performance of CRCS connections with tube plate
Rahman Jafari,Nader K.A. Attari,Ali Nikkhoo,Saeid Alizadeh 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.32 No.1
This paper presents experimental and analytical studies to evaluate the cyclic behaviour of Circular Reinforced Concrete column Steel beam (CRCS) connections. Two 3/4-scale CRCS specimens are tested under quasi-static reversed cyclic loading. Specimens were strengthened with a tube plate (TP) and a steel doubler plate (SDP). Furthermore; nine interior beam-through type RCS connections are simulated using nonlinear three-dimensional finite element method using ABAQUS software and are verified with experimental results. The results revealed that using the TP improves the performance of the panel zone by providing better confinement to the concrete. Utilizing the TP at the panel zone may absorb and distribute stress in this region. Results demonstrate that TP can be used instead of SDP. Test records indicate that specimens with TP, with and without SDP maintained their maximum strength up to 4% drift angle, satisfying the recommendation given by AISC341-2016 for composite special moment-resisting frames.
Resonance of a rectangular plate influenced by sequential moving masses
Hassanabadi, Mohsen Ebrahimzadeh,Attari, Nader K.A.,Nikkhoo, Ali,Mariani, Stefano Techno-Press 2016 Coupled systems mechanics Vol.5 No.1
In this work, an improved semi-analytical technique is adopted to track the dynamic response of thin rectangular plates excited by sequential traveling masses. This technique exploits a so-called indirect definition of inertial interaction between the moving masses and the plate and leads to a reduction, in the equations of motion, of the number of time-varying coefficients linked to the changing position of the masses. By employing this optimized method, the resonance of the plate can be obtained according to a parametric study of relevant maximum dynamic amplification factor. For the case of evenly spaced, equal masses travelling along a straight line, the resonance velocity of the masses themselves is also approximately predicted via a fast methodology based on the fundamental frequency of the system only.
Khodabandehloo, Mazaher,Hosseini, Weria,Rahmani, Mohammad-Reza,Rezaee, Mohammad-Ali,Hakhamaneshi, Mohammad-Saied,Nikkhoo, Bahram,Jalili, Ali Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.11
Background: Multiple etiologies have been hypothesized for prostate cancer, including genetic defects and infectious agents. A recently reported gamaretrovirus, xenotropic murine leukemia virus-related virus (XMRV) has been reported to be detected in prostate cancer. However, this virus has not been detected in similar groups of patients in other studies. Herein, we sought to detect XMRV in prostate cancers and benign controls in Sanandaj, west of Iran. Materials and Methods: In a case-control study, genomic DNA was extracted from formalin fixed and paraffin embedded prostate tissues from a total of 163 Iranian patients. We developed a conventional and a nested PCR assay using primers targeting to an env specific sequence of XMRV. PCR assays were carried out on 63 prostate cancers and 100 benign prostate hyperplasias. Results: Beta-actin sequences were successfully detected in the DNA extracts from all prostate tissues, confirming DNA extraction integrity. We did not detect XMRV in samples either from prostate cancers or benign prostate hyperplasias using XMRV specific primers. Conclusions: We conclude that in our population XMRV does not play a role in genesis of prostate cancer.