In this research, the active control of structures based on the critically damped condition was proposed for reducing displacements and drifts of structures under seismic loading. In this approach, the second-order dynamic equation is converted into a first-order dynamic equation and a first-order derivative operator with the same constants, which satisfy critically damped conditions of the system. Based on this concept and using the defined performance index, the feedback gain matrix of the structural velocity is obtained. In the method of active control of structures based on the critically damped condition, the control force, which is the linear definition of the feedback gain matrix and the structural velocity, is exerted on the structure in each time step. Four types of numerical examples are examined to the comparison verification of active control of structures based on the critically damped condition with the classical linear optimal control, standard model predictive control, and other methods proposed in several references. Programming and calculations are done by Mathcad prime mathematical software.

Background Endometriosis is a common benign but painful gynecologic condition. Studies suggest that the risk of some types of malignancies such as breast cancer is higher in women with endometriosis. Mammographic breast density (MBD) is known as an important predictor for breast cancer. The present study aimed to investigate the potential relationship between endometriosis and MBD. Methods This cross-sectional study was conducted on 370 women over 40 years of age. Laparoscopic surgery was carried out for the diagnosis of endometriosis. MBD was classified into four categories according to the ACR BI-RADS classification. Statistical analysis was performed using SPSS software to evaluate the potential association between variables. Results The mean age of all participants was 47.2±6.4 years, and most participants (76.8 %) were premenopausal. Multivariate analysis of the potential predictors of MBD, including age, body mass index, oral contraceptive consumption, progesterone consumption, family history of breast cancer and endometriosis showed that age (P-value=0.002), history of progesterone consumption (P-value=0.004) and endometriosis (P-value=0.006) were the independent factors for MBD. Conclusion This study indicated that endometriosis had an inverse association with MBD. Age and history of progesterone use were also independent influential factors for MBD. This finding shows that the positive association between breast cancer and endometriosis is not mediated through MBD.

Background: Tuberculosis (TB) is an infectious and communicable disease and one of the top ten causes of death throughout the world. Monitoring and evaluating TB treatment outcomes provides the required data for taking the necessary measures to control TB. Thus, this study was carried out to find determinants of treatment failure among patients with smear-positive pulmonary TB in Khuzestan province during 2006-2014 Material and Methods: This retrospective cohort study was conducted over a 9-year period in Khuzestan province. Predictors of treatment failure were analyzed using multivariate logistic regression Findings: Among 5342 patients, the cumulative incidence of unsuccessful TB treatment was 1.85%. More than half of TB patients (59.2%) enrolled in this study were male, and most of them were living in urban areas (79.8%). Significant predictors of treatment failure were age (p=•001), weight (p= •039), number of delayed days in diagnosis (p=•01), isoniazid resistance (p≤•001), and number of bacilli in patients` sputum at the beginning of treatment (p≤•001). Conclusion:In this study, the rate of successful treatment was quite high; nevertheless, new cases of treatment failure could be prevented with special efforts such as prompt diagnosis and precise follow-up under Direct Observation Treatment Short course (DOTS) strategy.