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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Journal of Mechanical Research and Application
- نوع مقاله: Journal Article
- کلمات کلیدی: Severe Plastic Deformation,high-strength tubes,NANO structured materials
- چکیده:
- چکیده انگلیسی: Increasing material’s strength is of particular importance. Improving material’s mechanical properties such as strength could reduce the size and weight of the structure. The size and weight of the structure are among the effective parameters in design. Since the past a variety of methods have been developed to increase the strength of metals that are capable of increasing metals’ strength to a certain level. But most of these methods while increasing strength are associated with relatively high material formability properties. This is one of the most important limitations of the methods. Plastic deformation method is among the new methods that in addition to increasing the material’s strength will strengthen other desired mechanical properties of the material by micro structuring the crystal lattice of a metal. The mechanical properties of the products of this process are so better than the original metal properties that they are known as super metals. Various methods have been developed to make the materials in tubes NANO structured. Products produced during these processes despite being thinner are less capable to withstand pressure and have higher corrosion and wear resistance compared to the tube manufactured by the conventional methods. Moreover they have the potential to be used at higher temperatures and have longer lifetime. These advantages have increased the importance of plastic deformation methods for the tubs. In this research while a brief discussion on the effect of severe plastic deformation on the material structure the conventional methods for manufacturing the tube are reviewed.
- انتشار مقاله: 30-04-1396
- نویسندگان: Seyed Hassan Sajjadi,Hossein Pure-Akbari,Sedghi Siamak,Omid Mirjaberi
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Chemical Health Risks
- نوع مقاله: Journal Article
- کلمات کلیدی:
- چکیده:
- چکیده انگلیسی: Gabapentin (GBP) is one of the new antiepileptic drugs (AEDs) applied extensively in neurology and psychiatry. The advantage of new AEDs includes newer mechanism of action, broad spectrum of anti-seizure effects, lesser drug interactions and fewer side effects. GBP is a cyclized analogue of GABA but it does not interact with GABA receptors, nor does it inhibit GABA uptake or prevent the degeneration of GABA. Restricted studies have been performed on acute and chronic effects of GBP on passive avoidance (PA) learning and little is known about its chronic phase. Therefore, the aim of the present study was to evaluate acute and chronic effects of GBP on passive avoidance learning in 100 mice (w=30 gr). Ten mg/kg GBP were injected interaperitoneally for assessment of memory in three steps (acquisition, consolidation and retrieval). Shuttle box trial was used for PA task assessment. Retrieval memory was tested 24h after injection, and the results indicated increased Step Through Latency (STL), showing the enhancement of memory. Moreover, in acute phase of PA, GBP enhanced acquisition and retrieval of memory. In chronic phase of PA, GBP showed no effect on memory. The present study suggests that GBP exerted no destructive effects on cognition; however, it improved emotional cognitive performance in mice in PA tasks.
- انتشار مقاله: 01-06-1393
- نویسندگان: Hormoz Ayromlou,Nooshin Masoudian,Naser Ahmadi-Asl,Parisa Habibi,Nahid Masoudian,Sasan Andalib,Maria Yazdani,Hossein Akbari
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Neonatology
- نوع مقاله: Journal Article
- کلمات کلیدی: Infant,Premature,Very low birth weight,Rickets
- چکیده:
- چکیده انگلیسی: Background: Metabolic bone diseases (MBD), including rickets and osteopenia, are important neonatal complications among preterm infants. This study aimed to determine the prevalence and risk factors of MBD in neonates with very low birth weight (VLBW). Methods: This prospective study was conducted on VLBW infants from January 2012 to July 2013. Inclusion criteria were birth weight of ≤1500 g and age of ≤7 days, and the exclusion criteria were cholestatic disorders, skeletal anomalies and genetic syndromes. Serum calcium, phosphorus and alkaline phosphatase (ALP) concentrations were measured regularly until the 12th week of birth. In addition, wrist and chest radiographs were obtained from the neonates at 8-12 weeks of age. Results: In total, 58 neonates with the mean gestational age of 30.6±2.65 weeks, weight of 1265±262 g and height of 38.06±2.49 cm were enrolled in this study. The correlation between biochemical parameters in multiple analysis and radiological findings of rickets was examined, and a significant association was observed between serum phosphorus level at the first week of age and the incidence of rickets. Moreover, 14 infants had only one radiologic sign of rickets (e.g. fraying, cupping, widening or lack of provisional zone of calcification (PZC), and 8 subjects (13.7%) showed at least two radiologic signs. The prevalence of osteopenia and rickets among infants with birth weight of <1200 g was 32.7% and 81.8%, respectively. In addition, 72.2% of the neonates with birth weight of >1200 g had normal X-rays (P=0.036). Conclusion: Despite the remarkable advances in the management of VLBW infants, MBD is still a prevalent complication during the neonatal period. According to the results of this study, birth weight and gestational age are the most significant risk factors for MBD.
- انتشار مقاله: 20-12-1393
- نویسندگان: Kobra Shiasi Arani,Asghar Lotfi,Mohammad Jahangiri,Hamid Reza Talari,Kamran Hami,Hossein Akbari
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Medical Sciences
- نوع مقاله: Journal Article
- کلمات کلیدی:
- چکیده:
- چکیده انگلیسی: Background: Goiter is thyroid enlargement, which is the most common visible symptom of iodine deficiency. Some studies have shown iodine deficiency in water, soil, and food in many places worldwide.We aimed to determine the prevalence of goiter and the association between urine iodine levels in children with severity and prevalence of goiter in mountainous villages of Kashan city (center of Iran). Methods: This descriptive-analytical study was performed on 263 children aged 6-12 years in villages of Kashan. In the present study, goiter and its grading was determined by WHO standard method. The patients’ urine iodine levels were measured by Pino method (ammonium oxidation) and compared with standard scales. Results: Of the children, 39.5% had goiter and the prevalence in girls was higher than boys (45.8% v 33.3%; P<0.03). All the patients with urine iodine level less than 25 µg/grcr (gram creatinine), 87.5% of patients with urine iodine level less than 100 µg/grcr and 24% of patients with urine iodine level more than 100 μg/grcr had goiter. Conclusion: The prevalence of goiter in mountainous places of Kashan is 39.5%. Although the people of these villages used iodized salt for years, these regions remain endemic parts of iodine deficiency. There was a significant association between urine iodine levels and the severity and prevalence of goiter (P< 0.001).
- انتشار مقاله: 23-02-1394
- نویسندگان: Ali Honarpisheh,Abbas Taghavi,Hossein Akbari
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Basic Medical Sciences
- نوع مقاله: Journal Article
- کلمات کلیدی: Regulatory T cells,Multiple Sclerosis,CD4+CD25+Foxp3+ -,CD8+CD28- Regulatory T cells
- چکیده:
- چکیده انگلیسی: Objective(s): Regulatory T cells, including CD4+CD25+Fox3+ and CD8+CD28- cells play an important role in regulating the balance between immunity and tolerance. Since multiple sclerosis is an inflammatory autoimmune disease, regulatory T cells are considered to be involved in its pathogenesis. In this study, we investigated the circulatory numbers of the two mentioned types of regulatory T cells and also their association with different clinical characteristics in 84 multiple sclerosis patients.
Materials and Methods: 84 patients with multiple sclerosis and 75 normal individuals were studied. Demographic and clinical information of all participants were collected via questionnaire and clinical examination as well as MRI. The peripheral blood frequency of two different subgroups of regulatory T cells (CD4+ CD25+Foxp3+ and CD8+CD28- cells) were analyzed by flow cytometry using anti-human antibodies conjugated with CD4-FITC / CD25-PE/Foxp3-PE-Cy5, CD3-PE/CD8a-PE-Cy5/CD28-FITC.
Results: The frequency of CD4+CD25+Foxp3+ cells in multiple sclerosis patients was significantly less than that in healthy controls (P=0.006) and in mild forms less than that in sever forms (P=0.003). There was not any correlation between the frequency of regulatory T cells and different clinical variables.
Conclusion: Our results showed that the number of CD4+CD25+Foxp3+ cells decreases significantly in multiple sclerosis patients, which probably shows the regulatory role of these cells in multiple sclerosis.- انتشار مقاله: 30-01-1393
- نویسندگان: Ebrahim Kouchaki,Mahdi Salehi,Mohammad Reza Sharif,Hassan Nikoueinejad,Hossein Akbari
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Engineering, Transactions A: Basics
- نوع مقاله: Journal Article
- کلمات کلیدی: Particle size,Cu,mechanical alloying,Cr Powder
- چکیده:
- چکیده انگلیسی: In the present work, the behavior of Cu-Cr powder mixtures during mechanical alloying has been studied. The powder mixtures with 1, 3 and 6 weight percents of Cr in Cu were treated. They were milled in a ball mill with two different speeds of 250 and 500 rpm using equal numbers of 1 and 2 centimeters balls. The weight ratio of balls to powders was 10 to 1 under argon atmosphere. Ethanol was used as the process control agent and milling times were 4, 12, 48 and 96 hours. After every hour of milling, a half–an–hour stop was applied to avoid temperature rise. The milled powder mixture was evaluated by a scanning electron microscope equipped with energy dispersive spectroscopy and an optical microscope equipped with image analyzer. Results have shown profound effects of milling conditions (the change in time, speed, etc.) on the behavior of milled powders.
- انتشار مقاله: 11-10-1348
- نویسندگان: Gholam Hossein Akbari,Majid Taghian
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Finance and Managerial Accounting
- نوع مقاله: Journal Article
- کلمات کلیدی: Portfolio optimization,Meta-Heuristic Algorithms,stock exchange market of Iran
- چکیده:
- چکیده انگلیسی: Portfolio selection process is a subject focused by many researchers. Various criteria involved in this process have undergone alterations over time, necessitating the use of appropriate investment decision support tools. An optimization approach used in different sciences is using meta-heuristic algorithms. In the present study, using Water Cycle Algorithm (WCA), a model was introduced for selecting the optimal portfolio, and then the obtained results were compared with those obtained from Harmony Search (HS) and Imperialist Competitive Algorithm (ICA). For this purpose, using the data of 10-month (April 2016 to January 2017) returns of 50 top companies in the Stock Exchange Market of Iran, the optimal portfolio was estimated using the above-mentioned algorithms with the aim of maximizing profit and minimizing risk, and then the optimal portfolios obtained from these algorithms were compared with each other. Results of implementing these algorithms indicated that despite the high capability of the studied algorithms to optimize the portfolios, WCA algorithm had higher capability of portfolio optimization than the other ones
- انتشار مقاله: 22-10-1397
- نویسندگان: Hossein Akbarifard,Reza Alaei
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Hospital Research
- نوع مقاله: Journal Article
- کلمات کلیدی: feasibility,Legal,Clinical nursing information systems,Nursing information system
- چکیده:
- چکیده انگلیسی: Background and Objectives: Legal considerations are essential to implement information system successfully. Therefore, the purpose of this study was to investigate the legal feasibility of clinical nursing information system (CNIS).
Methods: This research was a descriptive-cross sectional study. The instrument was developed through literature review. The psychometrics was confirmed by the CVR and CVI index based on comments of 15 experts. Reliability was approved by split method (α = 0.71). The evaluation was done on nursing administrators through a questionnaire with 5 options Likert scale and face to face interview. Scores less than 30 were considered as weak and poor, scores of 30-70 were treated as middle and relatively desirable, and scores more than 70 stood in high and desirable levels. The data was analyzed using chi-square tests, t test and two-way analysis of variance (ANOVA).
Results: Definition and develop of low, access to information, informing and implementation and revision should be included in the legal feasibility of CNIS. The percentage of supplied needs to implement the CNIS was 60%. The average score of legal feasibility was 66.46 %.
Conclusion: Appropriate and comprehensive legislation to allow the use of the previous system in case of system failure or high volume of work and the accurate determination of the level of user access is required.- انتشار مقاله: 20-11-1395
- نویسندگان: Fatemeh Rangraz Jeddi,Mohsen Adib Haj Bagheri,Hossein Akbari,Sohila Esmaili
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Advanced Biological and Biomedical Research
- نوع مقاله: Journal Article
- کلمات کلیدی: heavy metals,Phytoremediation,morphologic,Vigna Radiata,Cu
- چکیده:
- چکیده انگلیسی: Objective: To study plants purification capability of Cu on two cultivars of vetch plant (Vigna Radiata) in contaminated soils and their effects on morphological characteristics. Methods: we conducted a completely randomized trial as factorial. Different concentrations of Cu (0, 150, 300, and 400 mg/ Kg of dried soil) were used. After four weeks growth on contaminated soil, parameters such as aerial parts height, roots, fresh and dry weight, as well as intake and aggregation levels of Cu in aerial parts and roots were measured in both cultivars of Sistan and Gohar. Results: Analysis results indicated that increased levels of Copper to decreased height of aerial parts and roots, and dry and fresh weight of both cultivars. Measuring of metal content showed that with increase in metals concentration in soils, their aggregation into aerial parts will be increased. Metal aggregation within aerial parts and roots was not different significantly, indicating metals transferring from roots to aerial parts. Conclusions: Results show that the vetch plant is able to purify soils and intake heavy metals such as Cu from it.
- انتشار مقاله: 22-06-1393
- نویسندگان: Mehdi Keshtegar,Hossein Akbari Moghaddam,Alireza Akbari Moghaddam,Farzaneh Yaghobi Amirabadi,Omid Poudineh
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Advanced Studies in Humanities and Social Science
- نوع مقاله: Journal Article
- کلمات کلیدی: Company’s Value,Management Ownership,Ownership Adjustments
- چکیده:
- چکیده انگلیسی: In recent decades, the effect of management ownership on a company’s value has been a fundamental and noteworthy subject in companies’ organization and financial researches. In the current research, the effect of management ownership adjustments and its changes on a company’s value has been studied. In this regard, all the collected data were used from 52 companies that were accepted in Tehran Stock Exchange during the years 2006 to 2011. Management ownership and its transformations have been considered as independent variables in this research. The dependent variable that has been studied is the company’s value. Multiple regression and panel data methods have been used to test the hypothesis. Two hypotheses have been developed to accomplish this research: in the first one, the effect of management ownership adjustments on a company’s value has been studied. The first hypothesis result shows its acceptance in the significance level of 95%. In the second hypothesis, the changes of management ownership have been studied. The results of this hypothesis test showed that management ownership changes and transformations have a meaningful effect on a company’s value.
- انتشار مقاله: 09-01-1398
- نویسندگان: Najmeh Soleimani Dahaj,Mehdi Alinezhad Sarokolaei,Hossein Akbarifard
- مشاهده