The Effect of Y-Shaped Brace Configuration on Its Seismic Behavior

Saeed Najafi,Kaveh Saboohian,Shahin Borzoo 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.1

Incorporating bracing systems into seismic-resistant structures may induce some architectural limitations such as the impossibility of implementing openings. One of the considered solutions to solve the problem of opening in bracing systems without any architectural disruption is the Y-shaped bracing system. This research evaluates the behavior factor, stiff ness, ductility coeffi cient, and the rate of damping energy for the Y-shaped bracing systems. Finite element (FE) models are developed in Abaqus software, and the results are validated by comparing the results of FE analysis of a Y-shaped bracing frame and the results from an experimental model. Numerical evaluations show that fracture occurs in elements connected to the beamcolumn joints in the third member of a brace. A total of 5 models of bracing frames with diff erent middle node distances are used to investigate parameters such as behavior factor, stiff ness, ductility coeffi cient, and the rate of energy damping. The results suggest that geometrical modifi cation of the Y-shaped bracing frames can improve their seismic behavior, which can be evaluated using parameters such as behavior factor, plastic deformation of the structure, stiff ness, and other parameters in describing the seismic behavior of these structural systems.

Different strengthening designs and material properties on bending behavior of externally reinforced concrete slab

Najafi, Saeed,Borzoo, Shahin Techno-Press 2022 Structural monitoring and maintenance Vol.9 No.3

This study investigates the bending behavior of a composite concrete slab roof with different methods of externally strengthing using steel plates and carbon fiber reinforced polymer (CFRP) strips. First, the concrete slab model which was reinforced with CFRP strips on the bottom surface of it is validated using experimental data, and then, using numerical modeling, 7 different models of square-shaped composite slab roofs are developed in ABAQUS software using the finite element modeling. Developed models include steel rebar reinforced concrete slab with variable thickness of CFRP and steel plates. Considering the control sample which has no external reinforcement, a set of 8 different reinforcement states has been investigated. Each of these 8 states is examined with 6 different uncertainties in terms of the properties of the materials in the construction of concrete slabs, which make 48 numerical models. In all models loading process is continued until complete failure occurs. The results from numerical investigations showed using the steel plates as an executive method for strengthening, the bending capacity of reinforced concrete slabs is increased in the ultimate bearing capacity of the slab by about 1.69 to 2.48 times. Also using CFRP strips, the increases in ultimate bearing capacity of the slab were about 1.61 to 2.36 times in different models with different material uncertainties.

Reentrant Liquid-liquid Phase Separation Behaviors of Salmon Protamine Due to the Hydrophobicity of Arginine

Yuri HONG,Saeed NAJAFI,Thomas CASEY,Joan-Emma SHEA,Song-I HAN,Dong Soo HWANG 한국생물공학회 2023 한국생물공학회 학술대회 Vol.2023 No.4

Applicability of Radioguided Occult Lesion Localization for Non-Palpable Benign Breast Lesions, Comparison with Wire Localization, a Clinical Trial

Alikhassi, Afsaneh,Saeed, Farzanefar,Abbasi, Mehrshad,Omranipour, Ramesh,Mahmoodzadeh, Habibollah,Najafi, Massoome,Gity, Masoumeh,Kheradmand, Ali Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.7

Background: This study was designed to compare radioguided versus routine wire localization of nonpalpable non-malignant breast lesions in terms of efficacy for complete excision, ease of use, time saving, and cosmetic outcome. Materials and Methods: Patients with non-palpable breast masses and non-malignant core biopsy results who were candidates for complete surgical lumpectomy were enrolled and randomly assigned to radioguided or wire localization groups. Radiologic, surgical, and pathologic data were collected and analyzed to determine the difficulty and duration of each procedure, ease of use, accuracy, and cosmetic outcomes. Results: This prospective randomized study included 60 patients, randomly divided into wire guided localization (WGL) or radioguided occult lesion localization (ROLL) groups. The mean duration of localization under ultrasound guidance was shorter in the ROLL group (14.4 min) than in the WGL group (16.5 min) (p<0.001). The ROLL method was significantly easier for radiologists (p=0.0001). The mean duration of the surgical procedure was 22.6 min (${\pm}10.3min$) for ROLL and 23.6 min (${\pm}9.6min$) for WGL (p=0.6), a non-significant difference. Radiography of the surgical specimens showed 100% lesion excision with clear margins, as proved by pathologic examination, with both techniques. The surgical specimens were slightly heavier in the ROLL group, but the difference was not significant (p=0.06). Conclusions: The ROLL technique provides effective, fast, and simple localization and excision of non-palpable non-malignant breast lesions.

Simulation and in vitro evaluations of microfluidically-fabricated clarithromycin-poly (e-caprolactone) nanoparticles

Beeta Tavana,Alireza Khatibi,Saeed Jafarkhani,Payam Zahedi,Mohammad Hossein Zamani,Seyed Hassan Jafari,Mohammad Najafi 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.124 No.-

Clarithromycin (CLR)-loaded poly (e-caprolactone) (PCL) nanoparticles (NPs) were synthesized usingmicrofluidics (MF) with square-shaped (MF1), and three-channel (MF2), geometries as well as conventionalbulk mixing (BM). Based on Comsol simulation results of MF chips, the flow rate ratio, nonsolventphase flow rate, and polymer solution concentration were optimized 0.05, 50 mL h1, and 0.2(%w/v), respectively; thereby, representing MF1 geometry with highest homogenous mixing. Characterization studies indicated that MF1-based NPs possessed smaller average diameter (91 nm),narrower polydispersity index (0.13) and higher zeta potential (-44 mV) compared to those NPs synthesizedby MF2 and BM methods. Moreover, MF1-aided synthesis of NPs exhibited the encapsulation efficiencyof approximately 81% and loading capacity of around 13%. Investigating CLR release behavior atdifferent pHs also demonstrated that the MF1-based NPs experienced the most controlled release, followedthe Fickian diffusion mechanism. The controlled release of MF1-based NPs was confirmed by evaluatingtheir inhibitory effect against specific cytokines on BEAS-2B as bronchitis cell line via a series ofin vitro experiments including real time-polymerase chain reaction and flow cytometry. Eventually, theantibacterial properties of the samples were studied on two prevalent bacterial strains and the obtainedobservations revealed that MF1-based NPs encompassed the best performance in controlled release ofCLR with respect to the other samples.

Physical and Mechanical Properties of Wood-Plastic Composites Made with Microfibrillar Blends of LDPE, HDPE and PET

Seyyedeh Tahereh Mosavi-Mirkolaei,Saeed Kazemi Najafi,Mehdi Tajvidi 한국섬유공학회 2019 Fibers and polymers Vol.20 No.10

The effect of microfibrillar blends of recycled plastics on selected physical and mechanical characteristics ofwood-plastic composites (WPCs) was investigated in this study. The production of wood plastic composites was carried outthrough a two-step extrusion technique. The plastic blends were drawn after extrusion to obtain microfibrillar morphology. The addition of polyethylene-co-glycidyl methacrylate (E-GMA) enhanced compatibility between the two phases and ahomogenous structure was seen in the fracture surfaces by scanning electron microscopy (SEM). The crystallinity of basepolymers increased with the addition of polyethylene terephthalate (PET) microfibrils, E-GMA and wood flour. The X-raydiffraction (XRD) patterns were also used to determine the crystallinity of all samples. According to the XRD results, thecrystallinity degree of recycled plastics was higher than that of virgin plastics. E-GMA improved the water resistance ofwood-plastic composites. The mechanical properties of samples were improved with the addition of PET microfibrils. Themicrofibrillar blending technique was found to be an effective approach for the production of high quality WPCs fromrecycled plastic blends.

Comparision of Competence Assessment from the Viewpoint of Nurses and Headnurses

Marzieh Momennasab,Marzieh Moattari,Saeed Najafi,Afsaneh Besharati,Parisa Janghorban 한국간호과학회 2009 한국간호과학회 학술대회 Vol.2009 No.10

Dietary patterns, nutrition, and risk of breast cancer: a case-control study in the west of Iran

Behjat Marzbani,Javad Nazari,Farid Najafi,Behnaz Marzbani,Sara Shahabadi,Mahin Amini,Mehdi Moradinazar,Yahya Pasdar,Ebrahim Shakiba,Saeed Amini 한국역학회 2019 Epidemiology and Health Vol.41 No.-

OBJECTIVES: Unhealthy dietary patterns are the most important changeable risk factors for breast cancer. The aim of this study was to assess the relationship between dietary patterns and the risk of breast cancer among under-50 year women in the west of Iran. METHODS: All women under 50 years old with pathologically confirmed breast cancer between 2013 and 2015 who were referred to oncology clinics in the west of Iran, and 408 under-50 women referred to other outpatient clinics who were without breast or other cancers at the time of the study and 2 years later were selected as the control group. The data were collected using the middle-aged periodical care form of the Iranian Ministry of Health and analyzed using univariate and multivariate logistic regression in Stata. RESULTS: The most powerful risk factor for breast cancer was fried foods; the odds ratio of consuming fried foods more than once a month for breast cancer was 4.5 (95% confidence interval, 2.1 to 9.4). A dose-response model indicated that increasing vegetable and fruit consumption up to 90 servings per month decreased the odds of breast cancer, but consuming more than 90 servings per month increased the risk. CONCLUSIONS: Inadequate consumption of vegetables and consumption of soft drinks, industrially produced juices, fried foods, and sweets were identified as risk factors for breast cancer. In response to these findings, it is necessary to raise awareness and to provide education about healthy diets and the need to change unhealthy dietary patterns.

Evaluation of Factors Impacting Cosmetic Outcome of Breast Conservative Surgery - a Study in Iran

Olfatbakhsh, Asiie,Mehrdad, Neda,Ebrahimi, Mandana,Alavi, Nasrin,Hashemi, Esmat,Kaviani, Ahmad,Najafi, Masoume,Haghighat, Shahpar,Arefanian, Saeed Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.6

Background: Breast conservative surgery (BCS) followed by radiotherapy is the standard approach in management of stage I-II breast cancer. Several factors can affect cosmetic outcomes. The aim of this study was to evaluate the cosmetic results of BCS and influencing factors in the Iranian Breast Cancer Research Center. Materials and Methods: Patients who had undergone BCS were included. Photographs were taken of both breasts of the patients in three aspects and were evaluated by three specialists. The cosmetic scores were calculated based on a standard questionnaire. The data were analyzed using univariate and multivariate regression for relationships between cosmetic scores and clinical data. Results: A total number of 103 patients were included in the study. Mean age and BMI of the patients were $46.8{\pm}8.9$ and $28.1{\pm}3.9$, respectively. Breast cup sizes C and D accounted for 74.7% of the study group. The mean cosmetic score obtained from three referees was 5.72+2.06, consisting of 35.9% excellent-good, 35% moderate, and 29.1% unsatisfactory results. Patient BMI, volume of the resected tissue and breast cup size (D) showed significant correlation with the cosmetic score. On multivariate regression analysis, cosmetic score and BMI (p=0.022,) as well as breast cup size (p=0.040), remained significant. Conclusions: Immediate or delayed symmetrization of the breasts is suggested during breast conservative surgery, meanwhile performing oncoplastic techniques to improve the results significantly. Also it is suggested to discuss anticipation of less satisfactory results with patients having higher BMI and large breast cup size.

Stem Cell Tracing Through MR Molecular Imaging

Rasoul Yahyapour,Bagher Farhood,Ghazale Graily,Abolhasan Rezaeyan,Saeed Rezapoor,Hamid Abdollahi,Mohsen Cheki,Peyman Amini,Hengameh Fallah,Masoud Najafi,Elahe Motevaseli 한국조직공학과 재생의학회 2018 조직공학과 재생의학 Vol.15 No.3

Stem cell therapy opens a new window in medicine to overcome several diseases that remain incurable. It appears such diseases as cardiovascular disorders, brain injury, multiple sclerosis, urinary system diseases, cartilage lesions and diabetes are curable with stem cell transplantation. However, some questions related to stem cell therapy have remained unanswered. Stem cell imaging allows approval of appropriated strategies such as selection of the type and dose of stem cell, and also mode of cell delivery before being tested in clinical trials. MRI as a non-invasive imaging modality provides proper conditions for this aim. So far, different contrast agents such as superparamagnetic or paramagnetic nanoparticles, ultrasmall superparamagnetic nanoparticles, fluorine, gadolinium and some types of reporter genes have been used for imaging of stem cells. The core subject of these studies is to investigate the survival and differentiation of stem cells, contrast agent’s toxicity and long term following of transplanted cells. The promising results of in vivo and some clinical trial studies may raise hope for clinical stem cells imaging with MRI.