Quarter Car Active Suspension System: Minimum Time Controller Design Using Singular Perturbation Method

Younes Mohammadi,Soheil Ganjefar 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.6

Suspension systems have been widely applied to vehicles. Every vehicle moving on the randomly profiledroad is exposed to vibration and shocks which is harmful both for the passengers in terms of comfort andfor the durability of the vehicle itself. From this point of view, it is important to reset to zero displacement, velocityand acceleration of car in minimum time. So, this paper proposes a new minimum time controller basedon bang-bang control for the quarter car active suspension systems. First by using singular perturbation methodthe original suspension system is decomposed into two fast and slow singular subsystems in theory, and then byPontryagain’s Minimum Principle (PMP) and switching functions, the controller is designed for each subsystemand finally the optimal final time is obtained as maximum optimal time concluded of two subsystems. By using adegree of stability technique with two parameters (instead of four parameters), the optimal time is more reducedand leads to great simplifications in practical implementation. The performance of the controller is compared withthe Sub optimal Linear Quadratic Regulator (SLQR) controller using two types of road profiles (step and bump)implemented in MATLAB/Simulink. Test results demonstrate the proposed controller is very more effective andsimpler in eliminating fluctuations in suspension systems that finally provide the passengers comfort.

Transformation of the L-Asparaginase II Gene to Potato Hairy Roots for Production of Recombinant Protein

Azadeh Mohammadi,Ali Niazi,Farzaneh Aram,Farshid Hassani,Younes Ghasemi 한국작물학회 2020 Journal of crop science and biotechnology Vol.23 No.1

Nowadays, transgenic plants are considered as an expression system for therapeutic recombinant proteins. One of the approaches to recombinant protein production is the introduction of the relevant genes to plant cells and produce hairy roots from these cells using the plant tissue culture methods. L-asparaginase II is one of the important therapeutic enzymes used in the treatment of cancer, especially in the treatment of acute lymphoblastic leukemia (ALL) in children. In this study, L-asparaginase II (ansB) gene was isolated from Escherichia coli YG001 and overexpressed in Solanum tuberosum. The sequence of L-asparaginase II gene was optimized according to the codon usage table of S. tuberosum and cloned into the plant expression vector pBI121. Protein, DNA, and RNA of transgenic hairy roots were investigated. It was demonstrated that the ansB gene was correctly integrated into the genomic DNA of transgenic plants. The whole protein of transgenic roots was used for the assay of L-asparaginase II activity, the higher activity of L-asparaginase II was observed in transgenic hairy roots when compared with non-transgenic ones, and the recombinant protein was detected using western blot.

Vibration analysis of sandwich truncated conical shells with porous FG face sheets in various thermal surroundings

Mohsen Rahmani,Younes Mohammadi,Farshad Kakavand 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.32 No.2

Since conical sandwich shells are important structures in the modern industries, in this paper, for the first time, vibration behavior of the truncated conical sandwich shells which include temperature dependent porous FG face sheets and temperature dependent homogeneous core in various thermal conditions are investigated. A high order theory of sandwich shells which modified by considering the flexibility of the core and nonlinear von Karman strains are utilized. Power law rule which modified by considering the two types of porosity volume fractions are applied to model the functionally graded materials. By utilizing the Hamilton’s energy principle, and considering the in-plane and thermal stresses in the face-sheets and the core, the governing equations are obtained. A Galerkin procedure is used to solve the equations in a simply supported boundary condition. Uniform, linear and nonlinear temperature distributions are used to model the effect of the temperature changing in the sandwich shell. To verify the results of this study, they are compared with FEM results obtained by Abaqus software and for special cases with the results in literatures. Eigen frequencies variations are surveyed versus the temperature changing, geometrical effects, porosity, and some others in the numerical examples.

Using the capture-recapture method to estimate the human immunodeficiency virus-positive population

Jalal Poorolajal,Younes Mohammadi,Farzad Farzinara 한국역학회 2017 Epidemiology and Health Vol.39 No.-

OBJECTIVES: The capture-recapture method was applied to estimate the number of human immunodeficiency virus (HIV)-positive individuals not registered with any data sources. METHODS: This cross-sectional study was conducted in Lorestan Province, in the west of Iran, in 2016. Three incomplete sources of HIV-positive individuals, with partially overlapping data, were used, including: (a) transfusion center, (b) volunteer counseling and testing centers (VCTCs), and (c) prison. The 3-source capture-recapture method, using a log-linear model, was applied for data analysis. The Akaike information criterion and the Bayesian information criterion were used for model selection. RESULTS: Of the 2,456 HIV-positive patients registered in these 3 data sources, 1,175 (47.8%) were identified in transfusion center, 867 (35.3%) in VCTCs, and 414 (16.8%) in prison. After the exclusion of duplicate entries, 2,281 HIV-positive patients remained. Based on the capture-recapture method, 14,868 (95% confidence interval, 9,923 to 23,427) HIV-positive individuals were not identified in any of the registries. Therefore, the real number of HIV-positive individuals was estimated to be 17,149, and the overall completeness of the 3 registries was estimated to be around 13.3%. CONCLUSIONS: Based on capture-recapture estimates, a huge number of HIV-positive individuals are not registered with any of the provincial data sources. This is an urgent message for policymakers who plan and provide health care services for HIV-positive patients. Although the capture-recapture method is a useful statistical approach for estimating unknown populations, due to the assumptions and limitations of the method, the population size may be overestimated as it seems possible in our results.

Vibration of two types of porous FG sandwich conical shell with different boundary conditions

Mohsen Rahmani,Younes Mohammadi 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.79 No.4

In this paper, in various boundary conditions, the vibration behavior of the two types of porous FG truncated conical sandwich shells is investigated based on the improved high order sandwich shells theory. Two types of porosity are considered in the power law rule to model the FGM properties. In the first type, FG face sheets cover a homogeneous core, and in the second one, the FG core is covered by the homogeneous face sheets. All materials are temperature dependent. By utilizing the Hamilton’s energy principle, using the nonlinear von Karman strains in the layers and considering the in-plane stresses and thermal stresses in the core and the face sheets, the governing equations are obtained. A Galerkin method is used to solve the equations with clamped-clamped, clamped-free, and free-free boundary conditions. To validate the results, a FEM software is used and some results are validated with the results in the literatures. Also, Some geometrical parameters, temperature variations and porosity effects are studied. By increasing the length to thickness ratio, temperature, the semi-vertex angle and the radius to thickness ratio, the fundamental frequency parameter decreases in all boundary conditions. In both types of sandwiches for both porosity distributions, by increasing the porosity volume fraction, the fundamental frequency parameters increase. Frequency variation of type-II is lower than type-I in the thermal conditions. And the fundamental frequencies of the clamped-clamped (CC) and clamped-free (C-F) boundary conditions have the highest and lowest values, respectively.

Life expectancy of HIV-positive patients after diagnosis in Iran from 1986 to 2016: a retrospective cohort study at national and sub-national levels

Mohammad Mirzaei,Younes Mohammadi 한국역학회 2018 Epidemiology and Health Vol.40 No.-

OBJECTIVES: Little is known about the life expectancy of individuals with human immunodeficiency virus (HIV) in Iran. This study therefore aimed to estimate the life expectancy of HIV-positive patients in Iran. METHODS: In this retrospective cohort study, we extracted data from the Center for Disease Control and Prevention of the Ministry of Health and Medical Education and the Death Registration System. We included patients aged 20 years and older who had a specified date of diagnosis. We estimated life expectancy and its 95% confidence intervals (CIs) using Chiang’s methodology. RESULTS: The overall life expectancy at the national level was 23.1 years (95% CI, 22.6 to 23.5). Life expectancy was 21.6 years (95% CI, 21.1 to 22.0) for men and 32.7 years (95% CI, 31.4 to 34.0) for women. The life expectancy of patients who did or did not receive antiretroviral therapy (ART) was 37.0 years (95% CI, 36.2 to 37.8) and 15.5 years (95% CI, 15.1 to 15.9), respectively. The life expectancy of patients with or without tuberculosis (TB) was 21.6 years (95% CI, 20.4 to 22.9) and 36.5 years (95% CI, 35.7 to 37.4), respectively. CONCLUSIONS: The life expectancy of Iranian HIV-positive patients was found to be very low. To improve their longevity, improvements in ART coverage and the control and treatment of TB are advised.

Dental age estimation using cone-beam computed tomography: A systematic review and meta-analysis

Yousefi Faezeh,Mohammadi Younes,Ahmadvand Mehrnaz,Razaghi Parnian 대한영상치의학회 2023 Imaging Science in Dentistry Vol.53 No.2

Purpose: This systematic review aimed to investigate the correlation between chronological age and dental pulp volume in cone-beam computed tomography (CBCT). Materials and Methods: The literature was searched in 4 databases (PubMed, Scopus, Web of Science, and Google Scholar). Within each study, the outcome of interest was the correlation (r) between chronological age and pulp volume. A random-effect meta-analysis was conducted. Subgroup analysis was carried out according to sex and tooth type. Results: Of 5,693 identified studies, 27 fulfilled the inclusion criteria and were selected for meta-analysis. These articles focused on single-rooted teeth (n = 21), multi-rooted teeth (n = 6), maxillary teeth (n = 14), mandibular teeth (n = 6), and maxillary and mandibular teeth (n = 12). The relationship between chronological age and dental pulp volume was examined in the entire population (r = -0.67), men (r = -0.75), and women (r = -0.77) in single- and multi-rooted teeth. The results of the total population analysis showed a relatively strong negative relationship between age and pulp volume. Conclusion: This study suggested that CBCT is a reliable and repeatable tool for dental age estimation. A strong inverse relationship was observed between pulp chamber volume and age. Further studies on the correlation between chronological age and pulp volume of multi-rooted teeth may be beneficial.

Risk factors for stomach cancer: a systematic review and meta-analysis

Jalal Poorolajal,Leila Moradi,Younes Mohammadi,Zahra Cheraghi,Fatemeh Gohari-Ensaf 한국역학회 2020 Epidemiology and Health Vol.42 No.-

OBJECTIVES: This report provides information on 14 behavioral and nutritional factors that can be addressed in stomach cancer prevention programs. METHODS: PubMed, Web of Science, and Scopus were searched through December 2018. Reference lists were also screened. Observational studies addressing the associations between stomach cancer and behavioral factors were analyzed. Between-study heterogeneity was investigated using the χ2, τ2, and I2 statistics. The likelihood of publication bias was explored using the Begg and Egger tests and trim-and-fill analysis. Effect sizes were expressed as odds ratios (ORs) with 95% confidence intervals (CIs) using a random-effects model. RESULTS: Of 52,916 identified studies, 232 (including 33,831,063 participants) were eligible. The OR (95% CI) of factors associated with stomach cancer were as follows: Helicobacter pylori infection, 2.56 (95% CI, 2.18 to 3.00); current smoking, 1.61 (95% CI, 1.49 to 1.75); former smoking 1.43 (95% CI, 1.29 to 1.59); current drinking, 1.19 (95% CI, 1.10 to 1.29); former drinking, 1.73 (95% CI, 1.17 to 2.56); overweight/obesity, 0.89 (95% CI, 0.74 to 1.08); sufficient physical activity, 0.83 (95% CI, 0.68 to 1.02); consumption of fruits ≥3 times/wk, 0.48 (95% CI, 0.37 to 0.63); consumption of vegetables ≥3 times/wk, 0.62 (95% CI, 0.49 to 0.79); eating pickled vegetables, 1.28 (95% CI, 1.09 to 1.51); drinking black tea, 1.00 (95% CI, 0.84 to 1.20); drinking green tea, 0.88 (95% CI, 0.80 to 0.97); drinking coffee, 0.99 (95% CI, 0.88 to 1.11); eating fish ≥1 time/wk 0.79 (95% CI, 0.61 to 1.03); eating red meat ≥4 times/wk 1.31 (95% CI, 0.87 to 1.96), and high salt intake 3.78 (95% CI, 1.74 to 5.44) and 1.34 (95% CI, 0.88 to 2.03), based on two different studies. CONCLUSIONS: This meta-analysis provided a clear picture of the behavioral and nutritional factors associated with the development of stomach cancer. These results may be utilized for ranking and prioritizing preventable risk factors to implement effective prevention programs.

Factors Affecting Breast Self-examination Behavior Among Female Healthcare Workers in Iran: The Role of Social Support Theory

Bashirian, Saeed,Barati, Majid,Shoar, Leila Moaddab,Mohammadi, Younes,Dogonchi, Mitra The Korean Society for Preventive Medicine 2019 Journal of Preventive Medicine and Public Health Vol.52 No.4

Objectives: In women, breast cancer is the most common cancer and the leading cause of cancer death. Screening tests are the basis for early diagnosis. In Iranian women, the mortality rate of breast cancer is high due to insufficient screening examinations and delayed visits for care. Therefore, this study aimed to determine the factors affecting breast self-examinations among Iranian women employed in medical careers. Methods: This cross-sectional study included 501 women working in the medical professions at Hamadan University of Medical Sciences in western Iran in 2018. The subjects were selected by stratified random sampling. Data were collected using a researcher-developed, self-report questionnaire that contained demographic information and questions based on protection motivation theory and social support theory. Descriptive data analysis was conducted using SPSS version 23 and model fitting with PLS version 2. Results: The mean age of the participants was $37.1{\pm}8.3years$, and most of the women (80.4%) were married. Most women had a bachelor's degree (67.5%). The findings of this study showed that the coping appraisal construct was a predictor of protection motivation (${\beta}=0.380$, p<0.05), and protection motivation (${\beta}=0.604$, p<0.05) was a predictor of breast self-examination behavior. Additionally, social support theory (${\beta}=0.202$, p<0.05) had a significant positive effect on breast self-examination behavior. Conclusions: The frequency of practicing self-examinations among women employees in the medical sector was low; considering the influence of social support as a factor promoting screening, it is necessary to pay attention to influential people in women's lives when designing educational interventions.

The Effect of Comfrey on Enoxaparin-Induced Bruise in Patients with Acute Coronary Syndrome: A Randomised Clinical Trial

Bagheri Zahra,Azizi Azim,Oshvandi Khodayar,Mohammadi Younes,Larki-Harchegani Amir 대한약침학회 2021 Journal of pharmacopuncture Vol.24 No.4

Objectives: Bruising is an important side effect of enoxaparin injection. Comfrey (Symphytum officinale) is used to treat different types of wounds, bone fractures, and bruising in traditional medicine in many countries for centuries. This study aimed to determine the effects of the Comfrey ointment on the bruise size and color following enoxaparin injection. Methods: This double-blind randomized clinical trial was conducted on 80 patients with acute coronary syndrome (ACS). The participants were randomly divided into two groups of 40, namely Comfrey and Placebo. Changes in bruise size and color in both groups were assessed daily before and after the intervention. Results: The Comfrey and Placebo groups were homogeneous in demographic and clinical variables. A downward trend was observed in the bruise size in both groups throughout the study. However, the bruise size was smaller in the Comfrey group than the Placebo group on day 2-5 of the intervention. Moreover, there was a significant difference in bruise color between the groups, with a shorter healing course in the Comfrey group. Conclusion: The Comfrey ointment accelerated the healing process of enoxaparin injection-induced bruising in patients with ACS. It is recommended as a safe and simple approach for these patients.