Selection of Viscous Damping Model for Evaluation of Seismic Responses of Buildings

Hamid Zand,Jalal Akbari 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.11

Users of structural analysis software commonly apply the Rayleigh damping model as a default option for analyzing of structures. When a distributed plasticity model is utilized in the numerical models, the structural responses are not found to be sensitive to the damping models; even the Rayleigh damping model leads to the reasonable seismic results. Moreover, the lower bounds and upper bounds of the demands are sensitive to the type of damping model. In this paper, the effects of viscous damping models in the seismic demands of moment and concentrically braced steel frames are carefully investigated. For this purpose, seven viscous damping models are considered using the different forms of the stiffness matrices in the finite-element modeling. The declared structural systems are modeled against several strong ground motion records in OpenSees environment. Then, the seismic responses such as drifts, accelerations and base shears are compared for the aforementioned damping models. The main result of this research is that applying Rayleigh damping model, as a default option for structural analyzing software will produce underestimated responses. In addition, it is shown that no matter which type of stiffness matrix is used in the stiffness proportional damping model. Therefore, using initial stiffness matrix is cost efficient, particularly in time-consuming nonlinear analyses.

Development of an electrochemical fentanyl nanosensor based on MWCNT-HA/ Cu-H3BTC nanocomposite

Maryam Akbari,Maryam Saleh Mohammadnia,Masoumeh Ghalkhani,Mohammad Aghaei,Esmail Sohouli,Mehdi Rahimi-Nasrabadi,Mohsen Arbabi,Hamid Reza Banafshe,Ali Sobhani-Nasab 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.114 No.-

Fentanyl is a potent narcotic drug with the same effects as morphine or heroin, but it’s significantly morepotent than these drugs. That means a tiny dose can have a dangerous impact and is also lethal, so it isessential to measure it. In this work, we have developed a new electrochemical sensor to measure thisdeadly drug utilizing a nanocomposite of multi-walled carbon nanotube, hydroxyapatite, and copperbasedmetal–organic framework (MWCNT-HA/Cu-H3BTC). The nanocomposite was first examined byX-ray diffraction, field emission scanning electron, Infrared, and Raman spectroscopic techniques. Theglassy carbon electrode (GCE) modified with MWCNT-HA/Cu-H3BTC was employed to determine fentanylin aqueous solutions. The highest oxidation current was generated for fentanyl at GCE/MWCNT-HA/Cu-H3BTC compared to the GCE, GCE/MWCNT, GCE/MWCNT/HA, and GCE/Cu-H3BTC. The GCE/MWCNT-HA/Cu-H3BTC showed a linear relationship between the concentration and the oxidation current of fentanylin the 0.01 to 100 lM with a detection limit of 3 nM. Finally, the fentanyl quantification in blood serumsamples was successfully performed. The GCE/MWCNT-HA/Cu-H3BTC’s reproducibility and stability wereindeed excellent.

Assessing the anion type effect on the hydro-mechanical properties of smectite from macro and micro-structure aspects

Goodarzi, Amir R.,Akbari, Hamid R. Techno-Press 2014 Geomechanics & engineering Vol.7 No.2

The expansivity of clayey soils is a complicated phenomenon which may affect the stability of geotechnical structures and geo-environmental projects. In all common factors for the monitoring of soil expansion, less attention is given to anion type of pore space solutions. Therefore, this paper is concerned with the impact of various concentrations of different inorganic salts including NaCl, $Na_2SO_4$, and $Na_2CO_3$ on the macro and microstructure behavior of the expandable smectite clay. Comparison of the responses of the smectite/NaCl and smectite/$Na_2SO_4$ mixtures indicates that the effect of anion valance on the soil engineering properties is not very pronounced, regardless of the electrolyte concentration. However, at presence of carbonate as potential determining ions (PDIs) the swelling power increases up to 1.5 times compared to sulfate or chloride ions. The samples with $Na_2CO_3$ are also more deformable and show lower osmotic compressibility than the other mixtures. This demonstrates that the barrier performance of smectite greatly decreases in case of anions with the non-specific adsorption (e.g., $Cl^-$ and $SO{_4}^{2-}$) as the salinity of solution increases. Based on the results of the X-ray diffraction and sedimentation tests, the high soil volumetric changes upon exposure to carbonate is attributed to an increase in the repulsive forces between smectite basic unit layers due to the PDI effect of $CO{_3}^{2-}$ and increasing the pH level which enhance the buffering capacity of smectite. The study concluded that the nature of anion through its influence on the re-arrangement of soil microstructure and osmotic phenomena governs the hydro-mechanical parameters of expansive clays. It seems not coinciding with the double layer theory of the Gouy-Chapman double layer model.

Application of a Non-Mixture Cure Rate Model for Analyzing Survival of Patients with Breast Cancer

Baghestani, Ahmad Reza,Moghaddam, Sahar Saeedi,Majd, Hamid Alavi,Akbari, Mohammad Esmaeil,Nafissi, Nahid,Gohari, Kimiya Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.16

Background: As a result of significant progress made in treatment of many types of cancers during the last few decades, there have been an increased number of patients who do not experience mortality. We refer to these observations as cure or immune and models for survival data which include cure fraction are known as cure rate models or long-term survival models. Materials and Methods: In this study we used the data collected from 438 female patients with breast cancer registered in the Cancer Research Center in Shahid Beheshti University of Medical Sciences, Tehran, Iran. The patients had been diagnosed from 1992 to 2012 and were followed up until October 2014. We had to exclude some because of incomplete information. Phone calls were made to confirm whether the patients were still alive or not. Deaths due to breast cancer were regarded as failure. To identify clinical, pathological, and biological characteristics of patients that might have had an effect on survival of the patients we used a non-mixture cure rate model; in addition, a Weibull distribution was proposed for the survival time. Analyses were performed using STATA version 14. The significance level was set at $P{\leq}0.05$. Results: A total of 75 patients (17.1%) died due to breast cancer during the study, up to the last follow-up. Numbers of metastatic lymph nodes and histologic grade were significant factors. The cure fraction was estimated to be 58%. Conclusions: When a cure fraction is not available, the analysis will be changed to standard approaches of survival analysis; however when the data indicate that the cure fraction is available, we suggest analysis of survival data via cure models.

Rate-based simulation and comparison of various promoters for CO2 capture in industrial DEA-promoted potassium carbonate absorption unit

Tohid Nejad Ghaffar Borhani,Vahid Akbari,Mohammad Kamaruddin Abdul Hamid,Zainuddin Abdul Manan 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.22 No.-

Diethanolamine (DEA)-promoted potassium carbonate process for CO2 removal is modelled using ratebasedapproach and Electrolyte NRTLmodel. Acceptable agreements between the simulation results andthe experimental data are achieved. The effectiveness of monoethanolamine (MEA), diglycolamine(DGA), diisopropanolamine (DIPA), and methyldiethanolamine (MDEA) as promoters are investigated. MEA shows promising performance for CO2 removal. The CO2 absorptions by DGA and DIPA are goodenough, but their prices are higher than MEA and DEA. The CO2 absorption byMDEA is not significant andit cannot be used as a promoter. A parametric study is performed to assess the effects of importantprocess parameters.

Survival Analysis of Patients with Breast Cancer using Weibull Parametric Model

Baghestani, Ahmad Reza,Moghaddam, Sahar Saeedi,Majd, Hamid Alavi,Akbari, Mohammad Esmaeil,Nafissi, Nahid,Gohari, Kimiya Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.18

Background: The Cox model is known as one of the most frequently-used methods for analyzing survival data. However, in some situations parametric methods may provide better estimates. In this study, a Weibull parametric model was employed to assess possible prognostic factors that may affect the survival of patients with breast cancer. Materials and Methods: We studied 438 patients with breast cancer who visited and were treated at the Cancer Research Center in Shahid Beheshti University of Medical Sciences during 1992 to 2012; the patients were followed up until October 2014. Patients or family members were contacted via telephone calls to confirm whether they were still alive. Clinical, pathological, and biological variables as potential prognostic factors were entered in univariate and multivariate analyses. The log-rank test and the Weibull parametric model with a forward approach, respectively, were used for univariate and multivariate analyses. All analyses were performed using STATA version 11. A P-value lower than 0.05 was defined as significant. Results: On univariate analysis, age at diagnosis, level of education, type of surgery, lymph node status, tumor size, stage, histologic grade, estrogen receptor, progesterone receptor, and lymphovascular invasion had a statistically significant effect on survival time. On multivariate analysis, lymph node status, stage, histologic grade, and lymphovascular invasion were statistically significant. The one-year overall survival rate was 98%. Conclusions: Based on these data and using Weibull parametric model with a forward approach, we found out that patients with lymphovascular invasion were at 2.13 times greater risk of death due to breast cancer.

Dopamine Receptor Gene (DRD1-DRD5) Expression Changes as Stress Factors Associated with Breast Cancer

Pornour, Majid,Ahangari, Ghasem,Hejazi, Seyed Hesam,Ahmadkhaniha, Hamid Reza,Akbari, Mohamad Esmail Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.23

Breast cancer is the most common cancer among females worldwide and a most prevalent malignancy in Iranian women. Chronic stress may make an important contribution to cancer, especially in the breast. Numerous studies showed roles of neurotransmitters in the occurrence and progression of cancers which are mediated by their various types of receptors. This study was conducted to evaluate alterations in the expression profile of dopamine receptor genes in peripheral blood mononuclear cells (PBMC) as stress factors in breast cancer patients and the human breast cancer cell line (MCF-7). Peripheral blood samples were obtained from 30 patients and 30 healthy individuals. Total mRNA was extracted from PBMC and MCF-7 cells and RT-PCR was performed to confirm the presence of five dopamine receptors (DRD1-DRD5). Expression changes of dopamine receptor genes were evaluated by real time PCR. We observed that DRD2-DRD4 in PBMCs of breast cancer patients were increased compared to healthy individuals. In addition, all dopamine receptor subtypes but DRD1 were expressed in MCF-7 cells. Therefore, alterations of these receptors as stress factors should be assessed for selecting appropriate drugs such as D2-like agonists for treatment of breast cancer after performing complimentary tests. Determining the expression profile of dopamine receptor genes thus seems promising.

Evaluation of Gene Expression Changes of Serotonin Receptors, 5-HT3AR and 5-HT2AR as Main Stress Factors in Breast Cancer Patients

Hejazi, Seyed Hesam,Ahangari, Ghasem,Pornour, Majid,Deezagi, Abdolkhaleagh,Aminzadeh, Saeed,Ahmadkhaniha, Hamid Reza,Akbari, Mohamad Esmail Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.11

Breast cancer is a serious and potentially lethal multi-factor disease among 40-50 aged women in both developed and developing countries. Also, various studies have pointed to roles of neurotransmitters like serotonin in development of cancers, through action on various types of receptors. This study was conducted to evaluate serotonin receptor (5HT2AR and 5HT3AR) genes expression in peripheral blood mononuclear cells (PBMCs) of breast cancer patients in comparison with the healthy people and in the MCF7 cell line. Peripheral blood samples were obtained from 30 patients and 30 healthy individuals. Total RNA was extracted from PBMCs and MCF-7 cells. and 5HT2AR and 5HT3AR were detected by RT-PCR techniques. Finally, serotonin receptor gene expression variation in breast cancer patients and MCF-7 cells were determined by real time-PCR. This latter indicated significant promotion in expression of 5HT3AR and 5HT2AR in PBMCs in breast cancer patients but expression of 5HT2AR in the MCF-7 cell line was significantly decreased. In conclusion, after performing complimentary tests, determine of gene expression changes in serotonin receptors (5HT2AR and 5HT3AR) may be useful as a new approach in treatment of breast cancer based on use of antagonists.

Determination of Buprenorphine in Raw Material and Pharmaceutical Products Using Ion-pair Formation

Amanlou, Massoud,Khosravian, Peghah,Souri, Effat,Dadrass, Orkideh Ghorban,Dinarvand, Rasoul,Alimorad, Mohammad Massoud,Akbari, Hamid Korean Chemical Society 2007 Bulletin of the Korean Chemical Society Vol.28 No.2

A simple and sensitive extractive spectrophotometric method has been described for the determination of buprenorphine either in raw material or in pharmaceutical formulations. The developed method is based on the formation of a colored ion-pair complex (1 : 1 drug/dye) of buprenorphine and bromocresol green (BCG) in buffer pH 3 and extracting in chloroform. The extracted complex shows absorbance maxima at 415 nm. Beer's law is obeyed in the concentration range of 1.32-100.81 μ g mL-1. The proposed method has been applied successfully for the determination of drug in commercial sublingual tablets and injectable dosage form. No significant interference was observed from the excipients commonly used as pharmaceutical aids with the assay procedure.

Determination of Buprenorphine in Raw Material and Pharmaceutical Products Using Ion-pair Formation

Massoud Amanlou*,Peghah Khosravian,Effat Souri,Orkideh Ghorban Dadrass,Rasoul Dinarvand,Mohammad Massoud Alimorad,Hamid Akbari 대한화학회 2007 Bulletin of the Korean Chemical Society Vol.28 No.2

A simple and sensitive extractive spectrophotometric method has been described for the determination of buprenorphine either in raw material or in pharmaceutical formulations. The developed method is based on the formation of a colored ion-pair complex (1 : 1 drug/dye) of buprenorphine and bromocresol green (BCG) in buffer pH 3 and extracting in chloroform. The extracted complex shows absorbance maxima at 415 nm. Beer's law is obeyed in the concentration range of 1.32-100.81 m g mL-1. The proposed method has been applied successfully for the determination of drug in commercial sublingual tablets and injectable dosage form. No significant interference was observed from the excipients commonly used as pharmaceutical aids with the assay procedure.