Traditionally Nocardia asteroids was considered the predominant species of causing no-cardiosis. The improved identification of isolates using molecular techniques have shown that the genus exhibits considerable taxon...Traditionally Nocardia asteroids was considered the predominant species of causing no-cardiosis. The improved identification of isolates using molecular techniques have shown that the genus exhibits considerable taxonomic complexity and phenotypic base identification can be ambiguous. The aim of this study was to assess the species distribution of Nocardia strains mostly recovered from patients suspected of having tuberculosis, during three years period (2009-2012). The clinical isolates were identified to species level using conventional tests and genotypic methods using single and multi locus sequence analysis (MLSA) of 16S rRNA, gyrB and secA1 genes. Nocardiosis was diagnosed in 46 patients. The most frequent underlying condition were organ transplantation (6 patients;13%), cancer (6 patients;13%), human immunodeficiency virus (HIV) (6 patients;13%), non-infectious chronic lung disease (5 patients;10.8%) and tuberculosis (4 patients;8.7%). Nocardia species was recovered from 46 different clinical specimens, the most common of which was bronchoalveolar lavage (BAL) (43.5%). Eleven different Nocardia species were identified: N. asteroides (n = 12), N. cyriacigeorgica (n = 9), N. farcinica (n = 7), N. wallacei (n = 6), N. carnea (n = 3), N. otitidiscaviarum (n = 3), N. abscessus (n = 1), N. arthritidis (n = 1), N. kruczakiae (n = 1), N. nova (n = 2) and N. veterana (n = 1). In conclusion, infection caused by Nocardia species appears to be more common than generally appreciated. The current study provides further evidence that Nocardia species are capable of causing a wide range of human diseases in healthy and immunocompromised patients. MLSA is a reliable method for accurate species identification of Nocardia isolates and would be more feasible for routine use in clinical laboratories.展开更多
Smart materials have found numerous applications in many areas in civil engineering recently. One class of these materials is shape memory alloy (SMA) which exhibits several unique characteristics such as superelastic...Smart materials have found numerous applications in many areas in civil engineering recently. One class of these materials is shape memory alloy (SMA) which exhibits several unique characteristics such as superelasticity and shape memory effect. Due to these characteristics, research efforts have been extended to use SMA in controlling civil structures. This paper investigates the effectiveness of SMA reinforcements in enhancing the behavior of shear walls, especially when subjected to seismic excitations. Two ordinary and coupled shear walls were introduced as reference structures and were modeled by ABAQUS software. For improving the seismic response of the shear walls, vertical SMA reinforcing bars were proposed to be implemented like conventional steel reinforcements, throughout the height of the structures and in every connecting beam in the coupled shear wall system. The one dimensional superelastic model of SMA material was implemented in the computer software using FORTRAN code. The dynamic response of the shear walls subjected to seismic loading was investigated through time history analyses under El-centro and Koyna records. The results showed that using superelastic SMA material instead of steel bars caused remarkable reduction in residual displacement for both ordinary and coupled shear walls. In addition, SMA reinforcements could significantly decrease the maximum deflection of the coupled shear wall system.展开更多
文摘Traditionally Nocardia asteroids was considered the predominant species of causing no-cardiosis. The improved identification of isolates using molecular techniques have shown that the genus exhibits considerable taxonomic complexity and phenotypic base identification can be ambiguous. The aim of this study was to assess the species distribution of Nocardia strains mostly recovered from patients suspected of having tuberculosis, during three years period (2009-2012). The clinical isolates were identified to species level using conventional tests and genotypic methods using single and multi locus sequence analysis (MLSA) of 16S rRNA, gyrB and secA1 genes. Nocardiosis was diagnosed in 46 patients. The most frequent underlying condition were organ transplantation (6 patients;13%), cancer (6 patients;13%), human immunodeficiency virus (HIV) (6 patients;13%), non-infectious chronic lung disease (5 patients;10.8%) and tuberculosis (4 patients;8.7%). Nocardia species was recovered from 46 different clinical specimens, the most common of which was bronchoalveolar lavage (BAL) (43.5%). Eleven different Nocardia species were identified: N. asteroides (n = 12), N. cyriacigeorgica (n = 9), N. farcinica (n = 7), N. wallacei (n = 6), N. carnea (n = 3), N. otitidiscaviarum (n = 3), N. abscessus (n = 1), N. arthritidis (n = 1), N. kruczakiae (n = 1), N. nova (n = 2) and N. veterana (n = 1). In conclusion, infection caused by Nocardia species appears to be more common than generally appreciated. The current study provides further evidence that Nocardia species are capable of causing a wide range of human diseases in healthy and immunocompromised patients. MLSA is a reliable method for accurate species identification of Nocardia isolates and would be more feasible for routine use in clinical laboratories.
文摘Smart materials have found numerous applications in many areas in civil engineering recently. One class of these materials is shape memory alloy (SMA) which exhibits several unique characteristics such as superelasticity and shape memory effect. Due to these characteristics, research efforts have been extended to use SMA in controlling civil structures. This paper investigates the effectiveness of SMA reinforcements in enhancing the behavior of shear walls, especially when subjected to seismic excitations. Two ordinary and coupled shear walls were introduced as reference structures and were modeled by ABAQUS software. For improving the seismic response of the shear walls, vertical SMA reinforcing bars were proposed to be implemented like conventional steel reinforcements, throughout the height of the structures and in every connecting beam in the coupled shear wall system. The one dimensional superelastic model of SMA material was implemented in the computer software using FORTRAN code. The dynamic response of the shear walls subjected to seismic loading was investigated through time history analyses under El-centro and Koyna records. The results showed that using superelastic SMA material instead of steel bars caused remarkable reduction in residual displacement for both ordinary and coupled shear walls. In addition, SMA reinforcements could significantly decrease the maximum deflection of the coupled shear wall system.
