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      • Preparation and characterization of a thermal responsive of poly(N-isopropylacrylamide)/chitosan/gelatin hydrogels

        Baghaei, Shaghayegh,Khorasani, Mohammad T. Techno-Press 2014 Biomaterials and Biomechanics in Bioengineering Vol.1 No.2

        Synthesis of interpenetrating polymer network (IPN) of chitosan-gelatin (Cs-Ge) (as a primary network) and N-isopropylacrylamide (NIPAAm) monomer (as the secondary network) was carried out with different ratio. Its structure was characterized by FT-IR, which indicated that the IPN was formed. The memberanes were studied by swelling, weight loss with time. The interior morphology of the IPN hydrogels was revealed by scanning electron microscopy (SEM); the IPN hydrogels showed a interpenetrated network of NIPAAm/chitosan has layers with more minute stoma and canals compared to interpenetrated network of NIPAAm/gelatin. Lower critical solution temperature (LCST), equilibrium swelling ratio (ESR) and deswelling kinetics were measured. The DSC results noticed that LCST of IPN hydrogels with different ratio of Cs/Ge/PNIPAAm are around $33{\pm}2^{\circ}C$. The ESR obtained results showed that with a ratio of Cs/Ge/NIPAAm: 1/1/6, the swelling ratio increased drastically from room temperature to $36^{\circ}C$ but with a ratio of Cs/Ge/PNIPAAm: 1/3/6, decrease significantly at the same condition. Therefore the hydrogels have been changed from a hydrophilic structure to a hydrophobic structure. Furthermore with an increase in temperature from room to the LCST, the ESR of IPN with higher concentration of (PNIPAAm) and (Ge) decreases but de-swelling kinetics of them are faster. Due to the suitable and different kinetics of de-swelling and the equilibrium swelling ratio (ESR) in various proportions, and because of the morphology inside the mass which confirms other tests, these hydrogels are very appropriate as a smart thermosensitive hydrogels with rapid response.

      • Preparation and characterization of a thermal responsive of poly(N-isopropylacrylamide)/chitosan/gelatin hydrogels

        Baghaei, Shaghayegh,Khorasani, Mohammad T. Techno-Press 2014 Biomaterials and biomedical engineering Vol.1 No.2

        Synthesis of interpenetrating polymer network (IPN) of chitosan-gelatin (Cs-Ge) (as a primary network) and N-isopropylacrylamide (NIPAAm) monomer (as the secondary network) was carried out with different ratio. Its structure was characterized by FT-IR, which indicated that the IPN was formed. The memberanes were studied by swelling, weight loss with time. The interior morphology of the IPN hydrogels was revealed by scanning electron microscopy (SEM); the IPN hydrogels showed a interpenetrated network of NIPAAm/chitosan has layers with more minute stoma and canals compared to interpenetrated network of NIPAAm/gelatin. Lower critical solution temperature (LCST), equilibrium swelling ratio (ESR) and deswelling kinetics were measured. The DSC results noticed that LCST of IPN hydrogels with different ratio of Cs/Ge/PNIPAAm are around $33{\pm}2^{\circ}C$. The ESR obtained results showed that with a ratio of Cs/Ge/NIPAAm: 1/1/6, the swelling ratio increased drastically from room temperature to $36^{\circ}C$ but with a ratio of Cs/Ge/PNIPAAm: 1/3/6, decrease significantly at the same condition. Therefore the hydrogels have been changed from a hydrophilic structure to a hydrophobic structure. Furthermore with an increase in temperature from room to the LCST, the ESR of IPN with higher concentration of (PNIPAAm) and (Ge) decreases but de-swelling kinetics of them are faster. Due to the suitable and different kinetics of de-swelling and the equilibrium swelling ratio (ESR) in various proportions, and because of the morphology inside the mass which confirms other tests, these hydrogels are very appropriate as a smart thermosensitive hydrogels with rapid response.

      • KCI등재

        Study on aerodynamic shape optimization of tall buildings using architectural modifications in order to reduce wake region

        Abdollah Baghaei Daemei,Seyed Rahman Eghbali 한국풍공학회 2019 Wind and Structures, An International Journal (WAS Vol.29 No.2

        One of the most important factors in tall buildings design in urban spaces is wind. The present study aims to investigate the aerodynamic behavior in the square and triangular footprint forms through aerodynamic modifications including rounded corners, chamfered corners and recessed corners in order to reduce the length of tall buildings wake region. The method used was similar to wind tunnel numerical simulation conducted on 16 building models through Autodesk Flow Design 2014 software. The findings revealed that in order to design tall 50 story buildings with a height of about 150 meters, the model in triangular footprint with aerodynamic modification of chamfered corner facing wind direction came out to have the best aerodynamic behavior comparing the other models. In comparison to the related reference model (i.e., the triangular footprint with sharp corners and no aerodynamic modification), it could reduce the length of the wake region about 50% in general. Also, the model with square footprint and aerodynamic modification of chamfered corner with the corner facing the wind could present favorable aerodynamic behavior comparing the other models of the same cluster. In comparison to the related reference model (i.e., the square footprint with sharp corners and no aerodynamic modification), it could decrease the wake region up to 30% lengthwise.

      • KCI등재

        Chattering-free sliding mode control with a fuzzy model for structural applications

        Keyvan Aghabalaei Baghaei,Hosein Ghaffarzadeh,S. Ali Hadigheh,Daniel Dias-da-Costa 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.69 No.3

        This paper proposes a chattering-free sliding mode control (CFSMC) method for seismically excited structures. The method is based on a fuzzy logic (FL) model applied to smooth the control force and eliminate chattering, where the switching part of the control law is replaced by an FL output. The CFSMC is robust and keeps the advantages of the conventional sliding mode control (SMC), whilst removing the chattering and avoiding the time-consuming process of generating fuzzy rule basis. The proposed method is tested on an 8-story shear frame equipped with an active tendon system. Results indicate that the new method not only can effectively enhance the seismic performance of the structural system compared to the SMC, but also ensure system stability and high accuracy with less computational cost. The CFSMC also requires less amount of energy from the active tendon system to produce the desired structural dynamic response.

      • Risk Factors for Lung Cancer Mortality in a Referral Center

        Jamaati, H,Baghaei, P,Sharifianfard, M,Emami, H,Najmi, K,Seifi, S,Salimi, B,Pourabdollah, M,Kiani, A,Hashemian, M,Khosravi, A Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.6

        Background: Lung cancer is one of the most common causes of death that is rising in many countries including Iran. This study aimed to determine the impact of factors on survival of lung cancer patients at a referral center of lung diseases in Tehran, Iran. Materials and Methods: A retrospective study was conducted on adult lung cancer cases admitted to a referral center for lung diseases from 2011 to 2015. Multivariate analysis was performed to determine the risk factors for all-cause mortality. Results: Of a total 933 patients with lung cancer, 53.4% died, 49.3% of them at the hospital. Overall median follow-up time was 7 months. The most common histological type of cancer was adenocarcinoma with a 13 month median survival time. Age ${\geq}55$ and smoking remained significant for all-cause mortality on Cox analysis, whereas gender was not. Conclusions: The survival of lung cancer patients is poor and the patients with history of smoking and age${\geq}55$ are at increased risk of death. Having a large hospital-based registry provides a good measurement of prognostic statistics for lung cancer. Further investigations are necessary to establish reasons for mortality.

      • KCI등재

        Comparative evaluation of effects of different surface treatment methods on bond strength between fiber post and composite core

        Ramin Mosharraf,Najmeh Baghaei Yazdi 대한치과보철학회 2012 The Journal of Advanced Prosthodontics Vol.4 No.2

        PURPOSE Debonding of a composite resin core of the fiber post often occurs at the interface between these two materials. The aim of this study was to evaluate the effects of different surface treatment methods on bond strength between fiber posts and composite core. MATERIALS AND METHODS Sixty-four fiber posts were picked in two groups (Hetco and Exacto). Each group was further divided into four subgroups using different surface treatments: 1) silanization; 2) sandblasting; 3) Treatment with 24% H2O2, and 4) no treatment (control group). A cylindrical plexiglass matrix was placed around the post and filled with the core resin composite. Specimens were stored in 5000 thermal cycles between 5℃ and 55℃. Tensile bond strength (TBS) test and evaluation using stereomicroscope were performed on the specimen and the data were analyzed using two-way ANOVA, Post Hoc Scheffe tests and Fisher's Exact Test (α=.05). RESULTS There was a significant difference between the effect of different surface treatments on TBS (P<.001) but different brands of post (P=.743) and interaction between the brand of post and surface treatment (P=.922) had no significant effect on TBS. Both silanization and sandblasting improved the bonding strength of fiber posts to composite resin core, but there were not any significant differences between these groups and control group. CONCLUSION There was not any significant difference between two brands of fiber posts that had been used in this study. Although silanization and sandblasting can improve the TBS, there was not any significant differences between surface treatments used.

      • Assessment of Cellular Proliferation in Oral Verrucous Carcinoma and Well-Differentiated Oral Squamous Cell Carcinoma Using Ki67: A Non-Reliable Factor for Differential Diagnosis?

        Zargaran, Massoumeh,Eshghyar, Nosratollah,Baghaei, Fahimeh,Moghimbeigi, Abbas Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.11

        Background: Non-invasive oral verrucous carcinoma (OVC) and invasive well-differentiated oral squamous cell carcinoma (OSCC) have similar histopathologic findings but different biological behavior. These two malignancies must be correctly differentiated by pathologists. The aim of this study was to determine immunohistochemical (IHC) expression of Ki67 in OVC and well-differentiated OSCC. Methods: Expression of Ki67 was evaluated by IHC in 15 cases of epithelial hyperplasia with no dysplasia (A group), 15 cases of OVC (B group), 12 cases of microinvasive OSCC(C group) and 15 cases of well-differentiated OSCC (D group). Results: There was a significant difference in Ki67 expression based on pattern distribution of immunostaining positive cells, with quantitative and semi-quantitative analyses, among the four groups ; also, between A group and each of the other three groups (P=0.0001). But there was no significant difference between B and C, C and D, and B and D groups (P>0.05). Conclusions: The three evaluation methods of Ki67 expression showed Ki67 (Mib-1) is not a good immunohistochemical marker to assess invasion status and differentiate OVC from well-differentiated OSCC; also, it cannot be used as a diagnostic tool to distinguish between variants of OSCC with similar grade.

      • Gastric Precancerous Lesions in First Degree Relatives of Patients with Known Gastric Cancer: a Cross-Sectional Prospective Study in Guilan Province, North of Iran

        Mansour-Ghanaei, Fariborz,Joukar, Farahnaz,Baghaei, Seyed Mohammad,Yousefi-Mashhoor, Mahmood,Naghipour, Mohammad Reza,Sanaei, Omid,Naghdipour, Misa,Shafighnia, Shora,Atrkar-Roushan, Zahra Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.5

        Background & Objectives: In patients with gastric cancer, the most frequently reported family history of cancer also involves the stomach. The aim of this study was to assess the presence of gastric precancerous lesions in first-degree relatives of patients with gastric cancer and to compare the obtained results with those of individuals with no such family history. Methods: Between 2007 and 2009, 503 consecutive persons more than 30 years old were enrolled in the study covering siblings, parents or children of patients with confirmed adenocarcinoma of stomach. The control group was made up of 592 patients who were synchronously undergoing upper gastrointestinal endoscopy for evaluation of dyspepsia without gastric cancer or any family history. All subjects were endoscopically examined. Results: The overall prevalence of Helicobacter pylori was 77.7% in the cancer relatives and in 75.7% in the control group. Chronic gastritis was found in 90.4% vs. 81.1% (P<0.001). Regarding histological findings, 37(7.4%) of the study group had atrophy vs. 12(1.7%) in the control group (P<0.001), while no difference was observed for intestinal metaplasia (20.3%vs. 21.6%, P=0.58). Dysplasia were shown in 4% of cancer relatives but only 0.4% of the control group (P<0.001). There was no gender specificity. Conclusions: Findings of our study point to great importance of screening in relatives of gastric cancer patients in Iran.

      • KCI등재

        Modeling and simulation of tanks-in-series airlift bioreactors for production of lactic acid by fermentation

        Leila Vafajoo,Houman Savoji,Roozbeh Fayal,Ali Baghaei 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.8

        A tanks-in-series model was applied for mathematical modeling of the unsteady state performance of 70and 100 liters airlift bioreactor for the production of lactic acid by fermentation. A set of first-order differential equations for the material balances of micro-organism, substrate, product, and dissolved oxygen around hypothetically well mixed stages was solved simultaneously utilizing computer program in MATLAB. The kinetic model utilized considered the effect of two substrates (glucose and dissolved oxygen) on the growth rate. The effect of air velocity on the lactic acid production was investigated. Results of this model have been validated with experimental data.

      • KCI등재

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