81 results on '"Ebrahimi, Mohammad"'
Search Results
2. Participatory Plant Breeding in Relation to Genetic Diversity, Food Security, Plant Development and the Need to Pay Attention to Oilseed Crops.
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Kakaei, Mehdi and Ebrahimi, Mohammad Ali
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PLANT breeding , *GENETIC variation , *FOOD security , *PLANT development , *OILSEEDS - Abstract
Since the beginning of life on earth, mankind has always used animals and plants for its nutrition and has continuously trained and developed them for their benefits and social, cultural, and economic needs. In the past, livestock and crop breeding were done by traditional farmers and ranchers. It improves the performance of livestock and crops, they performed the selection, which is one of the principles of plant breeding and livestock breeding. They made this choice with the help of information that was passed down to them from successive generations. It is a participatory plant breeding and production of crops with the help of researchers alongside farmers. Farmers work with researchers, scientists, and other stakeholders -even consumers-to improve crops and develop resilient plant varieties. Farmers are aware of their needs and have a conscious understanding of their agricultural land in terms of soil type, seed type, weather conditions, surface water, underground water conditions, etc. Therefore, they can play an important role in making decisions about the implementation of plant breeding and the type of planting pattern in the cultivated microclimates. In other words, farmers determine their cultivation goals based on their environments, conditions, tastes, and local cultures. The seed that is obtained in this way by the breed researchers with the help of the leading farmers, actually contributes significantly to the food governance of the people of that region and that country. [ABSTRACT FROM AUTHOR]
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- 2023
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3. Lupus Anticoagulant Is Associated with Critical Cases and High Mortality in COVID-19: A Literature Review.
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Moafi, Maral, Ebrahimi, Mohammad Javad, Hatami, Firouze, Gharehbagh, Farid Javandoust, Ahmadzadeh, Arman, Emam, Mohammad Mehdi, Rajaei, Alireza, Mansouri, Davood, and Darazam, Ilad Alavi
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LITERATURE reviews , *COVID-19 , *COVID-19 pandemic , *OLDER women , *COMPUTED tomography - Abstract
Background: In severe COVID-19 cases, a hypercoagulable state may occur. Antiphospholipid syndrome-related auto-antibodies (APSRAs) contribute to coagulopathy, but their role in COVID-19 remains unclear. We aimed to investigate the prevalence of positive APSRAs and their effect on clinical outcomes in confirmed COVID-19 patients. Materials and Methods: In this cross-sectional study, severe hospitalized COVID-19 cases were enrolled. Demographic and clinical data were obtained from the day of admission. APSRAs including IgG and/or IgM anticardiolipin (aCL) and anti-ß2-glycoprotein1 (anti-ß2GP1) as well as lupus anticoagulant (LAC) were measured. Results: In this study, 54 severe COVID-19 cases with positive RT-PCR and chest CT scans were recruited. Positive APSRAs were found in 7 (12.9%) patients. Positive LAC was a more prevalent marker as compared to other tests (11.1%). The prevalence of positive aCL (IgM or IgG) and anti-ß2 GPI (IgM or IgG) w as 1.8% (in an elderly woman). Lower oxygen saturation was found in the positive APSRAs group as opposed to the negative APSRAs group (70.3±9 vs. 84.8±9.7%). The mortality rate in the positive APSRAs group was significantly higher relative to the negative APSRAs group (83.3% vs. 27.1%; Pvalue: 0.01). Likewise, the mechanical ventilation requirement in the positive group was also higher (50% vs. 27.1%, P-value: 0.28). Conclusion: This study indicated that LAC might be associated with critical cases and high mortality of COVID-19. Nonetheless, the mortality was not related to macrothrombotic incidence. [ABSTRACT FROM AUTHOR]
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- 2023
4. Authors and affiliations.
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Sadatpour, Omid, Ebrahimi, Mohammad Taha, Akhtari, Maryam, Ahmadzadeh, Nooshin, Vojdanian, Mahdi, Jamshidi, Ahmadreza, Farhadi, Elham, and Mahmoudi, Mahdi
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MATRIX metalloproteinases , *BONE morphogenetic proteins , *MACROPHAGE colony-stimulating factor , *ANKYLOSING spondylitis , *MACROPHAGES , *ADENOSINES - Abstract
Background: Ankylosing spondylitis (AS) is an inflammatory autoimmune disease that mostly affects different joints of the body. Macrophages are the predominant cells that mediate disease progression by secreting several pro-inflammatory mediators. Different receptors are involved in macrophages' function including the adenosine receptors (AR). Our main objective in this study was to assess the effect of applying A2A adenosine receptor agonist (CGS-21,680) on the gene expression of inflammatory mediators including bone morphogenetic proteins (BMP)-2, 4 and matrix metalloproteinases (MMP)-3, 8, 9, and 13 on the macrophages from AS patients compared to healthy macrophages.Methods: Monocytes were isolated from the whole blood of 28 individuals (AS patients and healthy controls in a 1:1 ratio). Macrophages were differentiated using macrophage colony-stimulating factor (M-CSF), and flow cytometry was performed to confirm surface markers. CGS-21,680 was used to treat cells that had been differentiated. Using SYBR green real-time PCR, relative gene expression was determined.Results: Activating A2AAR diminished MMP8 expression in healthy macrophages while it cannot reduce MMP8 expression in patients' macrophages. The effect of A2AAR activation on the expression of BMP2 and MMP9 reached statistical significance neither in healthy macrophages nor in the patients' group. We also discovered a significant positive connection between MMP8 expression and patient scores on the Bath ankylosing spondylitis functional index (BASFI).Conclusion: Due to the disability of A2AAR activation in the reduction of MMP8 expression in patients' macrophages and the correlation of MMP8 expression with BASFI index in patients, these results represent defects and dysregulations in the related signaling pathway in patients' macrophages. [ABSTRACT FROM AUTHOR]- Published
- 2022
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5. Fabrication of Polyamide-6 Membranes—The Effect of Gelation Time towards Their Morphological, Physical and Transport Properties.
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Ebrahimi, Mohammad, Kujawski, Wojciech, and Fatyeyeva, Kateryna
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- 2022
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6. New hydroxylammonium-based protic ionic liquids: Influence of cation and anion structure on thermal, viscosity and conductive properties.
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Ebrahimi, Mohammad, Kobzar, Yaroslav, Kujawski, Wojciech, and Fatyeyeva, Kateryna
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IONIC conductivity , *IONIC liquids , *FOURIER transform infrared spectroscopy , *ANIONS , *NUCLEAR magnetic resonance , *VISCOSITY - Abstract
• New hydroxylammonium - based ILs. • Structure confirmed by FTIR and 1D NMR spectroscopy. • Correlation between chemical structure and ion conductivity. In the research work, new protic ionic liquids (Pr - ILs) were synthesized by an acid - base neutralization reaction. The influence of IL chemical structure (i.e. anion and cation nature) on the thermal behavior, viscosity and ionic conductivity was evaluated. To confirm the chemical structure of synthesized Pr - ILs, nuclear magnetic resonance (1H and 19F) and Fourier transform infrared spectroscopy analyses were performed. Thermal analysis demonstrated that the influence of anion nature on the IL thermal stability was more pronounced than that of cation. The ionic liquids with trifluoromethanesulfonate anion showed the highest thermal stability (T deg ∼ 410–420 °C) as compared with other studied anions (i.e. phosphate and acetate anions). The trifluoromethanesulfonate - based Pr - ILs also demonstrated high ionic conductivity – between ∼58 and ∼64 mS·cm−1 at 150 °C and non - humid conditions. Despite the fact that phosphate - based Pr - ILs were more thermally stable (T deg ∼ 250–280 °C) than acetate - based ones (T deg ∼ 215 °C), acetate - based Pr - ILs revealed a higher ionic conductivity (∼15–19 mS·cm−1 at 80 °C) than phosphate - based Pr - ILs (∼0.2–1 and ∼0.4–2 mS·cm−1 at 80 and 120 °C, respectively). The obtained results confirm that the synthesized Pr - ILs are promising candidates for using them in electrochemical applications, namely, electrodialysis and fuel cells. [ABSTRACT FROM AUTHOR]
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- 2024
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7. Corporate social responsibility and organizational commitment in agricultural cooperatives: evidence from Iran.
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Ebrahimi, Mohammad Sadegh and Ghaediyan, Mojtaba
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COOPERATIVE agriculture , *SOCIAL responsibility of business , *ORGANIZATIONAL commitment , *ORGANIZATIONAL behavior , *LEGAL liability , *ORGANIZATIONAL citizenship behavior - Published
- 2021
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8. FACTORS AFFECTING FARMERS' DESIRE TO CHANGE THE CULTIVATION PATTERN (MEDICINAL PLANTS CULTIVATION).
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YAQUBI, Roqu, EBRAHIMI, Mohammad Sadegh, and YAQUBI, Fatme
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DESIRE , *POPULATION statistics , *ENVIRONMENTAL protection , *AGRICULTURAL resources , *PLANT products , *MEDICINAL plants , *WAFER level packaging - Abstract
Achieving sustainable development is one of the most important agricultural resources. Therefore, the overall purpose of this study is to investigate the factors affecting farmers' desire to change the cultivation pattern to cultivation of medicinal plants. The research method is allowed as a field-library. After determining the variables through questionnaires and software SPSS. The statistical population of this study is rural producers in Targabah district in Khorasan Razavi Province in Iran. The statistical sample for this study was 204 rural households. The sample was calculated using random sampling based on Cochran formula. The results show that the farmers' desire to change the cultivation pattern to cultivation of medicinal plants has a significant positive correlation with its level of economic, social, technical and environmental awareness. Also, it has a significant and positive relationship with his understanding of the production of medicinal plants which can enhance the protection of the environment. The results of the diagnostic analysis showed that the level of economic awareness and awareness of processing plants and product packaging can affect the farmers' desire to change the cultivation pattern to cultivation of medicinal plants. [ABSTRACT FROM AUTHOR]
- Published
- 2021
9. The Predominance of Newcastle Disease Virus Genotype VII: Genome Diversity or Poor Cross-Immunity of non-Matched Vaccines.
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Shahsavandi, Shahla, Ebrahimi, Mohammad Majid, and Tebianian, Majid
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NEWCASTLE disease vaccines , *NEWCASTLE disease virus , *IMMUNE response , *BIOINFORMATICS , *GENOTYPES - Abstract
Introduction: The virulent Newcastle disease virus (NDV) strains cause an economically important infectious disease in poultry. The common vaccination program with genotype II NDV strains is routinely practiced to provide a better protection level against Newcastle disease (ND). Nevertheless, the emergence of new antigenic and genetic variants within the circulating NDVs raises the importance of improved control strategies. The genotype VII NDV is associated with many of the most recent outbreaks of the disease worldwide. Methods: We evaluated the impacts of genetic divergence between the genotypes II and VII on the immunity against NDV to choose a suitable vaccine virus candidate by focusing on the F and HN proteins. Comparative bioinformatics analyses based on B- and T-cell epitopes binding affinity, protein secondary structure and physicochemical properties predictions were applied for genotypes II and VII. Results: Although the results showed more differences in HN protein than F protein, there was no major difference between the predicted antigenicity values, epitope regions, affinity binding to MHC-I and MHC-II, secondary structures, surface accessibility, and stability of these immunogens between genotypes II and VII. Conclusion: The results suggest that genotype II-based live vaccines can induce immune responses against NDV; however, an inactivated vaccine formulated by genotype VII should be considered in combination with the traditional live vaccine to provide better protection in controlling programs against ND. [ABSTRACT FROM AUTHOR]
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- 2021
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10. The Relationship between the Metabolic Syndrome and the Risk of Obstructive Sleep Apnea Evaluated by STOP-Bang Questionnaire in Professional Drivers in Shahroud, Iran, in 2020: A Case-Control Study.
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Ebrahimi, Mohammad Hossein, Jahanfar, Shayesteh, and Shayestefar, Mina
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SLEEP apnea syndromes , *METABOLIC syndrome , *SNORING , *CASE-control method , *BODY mass index , *HYPERTENSION - Abstract
Background: The present study was conducted to investigate the relationship between metabolic syndrome and the risk of respiratory and sleep disorders in professional drivers. Methods: This case-control study was conducted on professional drivers in Shahroud, Iran. The snoring, tiredness during daytime, observed apnea, high blood pressure, body mass index, age, neck circumference, gender (STOP-Bang) questionnaire was first used to assess obstructive sleep apnea (OSA). Then, based on the questionnaire scores, the participants were divided into two groups: those with and those without OSA. The relationship between this disorder and metabolic syndrome was then studied. Data were analyzed using descriptive and analytical tests (P<0.05). Results: Based on the STOP-Bang questionnaire, 214 drivers with a high risk of OSA and 214 drivers with low risk were recruited for the study. According to the Adult Treatment Panel III criteria, 204 drivers (47.7%) had metabolic syndrome. There was a significant relationship between driver's license class and the risk of OSA. Metabolic syndrome components including fasting blood sugar, triglycerides, and hypertension, but not high-density lipoprotein cholesterol, were able to predict OSA in the professional drivers. Conclusion: Given the high prevalence of metabolic syndrome and OSA, especially in drivers of high risk who may spend long hours transporting good and operating passenger vehicles, screening and treating these disorders are crucial in this part of the population. The researchers recommend holding regular training sessions about these disorders for professional drivers. [ABSTRACT FROM AUTHOR]
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- 2021
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11. Fault-tolerant control of steer-by-wire systems under voltage and current sensors faults.
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Mortazavizadeh, Seyed Abolfazl, Ebrahimi, Mohammad, Ghaderi, Ahmad, and Hajian, Masood
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Steer-by-wire (SBW) systems benefit from several advantages including lower weight, volume, and cost compared to counterpart electric power steering systems. However, system reliability is impacted since SBW performance is highly dependent on correct operation of several voltage, current, speed, yaw rate, and position sensors. This paper presents a new method in SBW system reliability improvement by introducing a novel fault detection, isolation, and reconstruction (FDIR) control technique. The proposed FDIR method detects if any fault is observed on voltage or current sensors and identifies the faulty sensor location. Additionally the identified faulty sensor's output is replaced with an estimated value to allow system continuous fault-ride through operation. The SBW system equipped with proposed FDIR technique provides fault-tolerance property against up to 3 faulty voltage or current sensors. Therefore, enhanced overall reliability is obtained at no further hardware costs associated with additional sensors redundancy solutions. The proposed technique is studied using system modelling and hardware prototyping, and its effectiveness is demonstrated using simulation and experimental results. [ABSTRACT FROM AUTHOR]
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- 2021
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12. The Tween 80 Toxicity in Chicken Embryos and Effect on the Kinetics of Newcastle Disease Virus Replication.
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Shahsavandi, Shahla, Ebrahimi, Mohammad Majid, Ghadiri, Mohammad Bagher, and Samiee, Mohammad Reza
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NEWCASTLE disease virus , *CHICKEN embryos , *VIRAL replication , *NONIONIC surfactants , *MEMBRANE permeability (Biology) , *EGGS - Abstract
Background: Non-ionic surfactant, Tween-80 (TW80) is commonly used for drug delivery due to its effect on the cell membrane permeation. The change in permeability can also increase viral infectivity in cells. This study was undertaken to improve upon Newcastle disease virus (NDV) titer cultivated with embryonic chicken eggs. Methods: The toxicity of TW80 was investigated against chicken embryos at varying concentrations, and changes in the morphology and weights of the heart, liver, and spleen of 4-day old chicken embryos were analyzed. Also, the effect of non-toxic concentrations of TW80 was examined on the infectivity of NDV. The virus was titrated in the allantoic fluid, using a 50% embryo infectious dose (EID50). Results: At high concentrations of TW80, hemorrhage-induced mortality was observed in embryos at the early stages of incubation. The embryos' viability was not affected at low TW80 concentrations, indicating that its toxicity to the chicken embryos was dose-dependent. The infectivity titer of NDV was increased in the presence of TW80 compared to those inoculated with NDV only. Conclusion: The data suggest that TW80 is toxic to chicken embryos at high concentrations, but it enhances cell membrane permeability for NDV particles at low concentrations without affecting the embryos' viability. [ABSTRACT FROM AUTHOR]
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- 2020
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13. Selecting Representative Critical Paths for Sensor Placement Provides Early FPGA Aging Information.
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Ebrahimi, Mohammad and Navabi, Zainalabedin
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SENSOR placement , *GATE array circuits , *INFORMATION society , *FIELD programmable gate arrays - Abstract
This article proposes a methodology for critical path selection and delay sensor insertion for aging monitoring in field-programmable gate arrays (FPGAs). The aging information can be used to reconfigure FPGAs to achieve better performance or wear leveling. To filter out the paths aging less aggressively, our methodology decides based on both physical-level parameters [e.g., path delay, process variation, temperature, static stress (duty cycle), and dynamic stress (switching activity) as well as aging-relevant parameters (e.g., fan-out, and endpoint physical location)]. After selection of an optimal set of paths, age sensors, introduced in our earlier work, are placed in a distributed fashion throughout the FPGA area to provide aging information of its various parts as they are being used. Accurate aging models for FPGAs are required to determine the contribution of the above-mentioned parameters in aging. In this article, ASICs’ aging models are adapted for FPGAs through measurement-based fitting approach. The experimental results using various benchmarks reveal that our algorithm selects paths with a minimum error. [ABSTRACT FROM AUTHOR]
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- 2020
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14. LUT Input Reordering to Reduce Aging Impact on FPGA LUTs.
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Ebrahimi, Mohammad, Sadeghi, Rezgar, and Navabi, Zainalabedin
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HOT carriers , *FIELD programmable gate arrays , *BOOLEAN functions - Abstract
In this article, we propose a fine-grained FPGA aging mitigation method. Our method focuses on Look Up Tables (LUTs) on which Boolean functions are mapped. Based on our observations, for any configuration, even if it is carefully selected, a number of LUT transistors experience severe stress rates. Therefore, an algorithm is presented to select several alternative configurations for each LUT. Alternative configurations are obtained by LUT input reordering. These alternative configurations are rotationally loaded into the FPGA. Experimental results shows that our method achieves 263 and 14.1 percent Mean Time To Failure (MTTF) improvement for Hot Carrier Injection (HCI) and Bias Temperature Instability (BTI), respectively. Additionally, due to changing only local routings, our method imposes up to 1 percent performance overhead to the systems. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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15. ANALYSIS OF THE PADDY FARMERS' KNOWLEDGE ABOUT INTEGRATED WEED MANAGEMENT (IWM).
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SAYADMANSOUR, Iman and EBRAHIMI, Mohammad Sadegh
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FARMERS' attitudes , *RICE farmers , *FARMERS , *CRONBACH'S alpha , *AGRICULTURAL productivity - Abstract
In the recent years chemical control of weeds has become a dominant method of weed control. The heavy use of these chemicals has had a negative impact on the environment and human health. So this study tries to investigate the analysis paddy farmers' knowledge about integrated weed management (IWM) in Iran. The study was done by a descriptive-surveying method that including field and documentary data. The population of the study consisted of selected Dooreh - CHegeni farmers that cultivation wheat and rice together. Sample population was selected by using the Cochran formula (n=198). The main instrument used in this study was a questionnaire. The validity of research tool was obtained by the idea of experts and for reliability of questionnaires a pilot test was conducted. The Cronbach' Alpha coefficient of higher than 0.7 showed that research tool was reliable (learning style (0.818), economic characteristic (0.700) and social characteristic (0.723) respectively). The result of correlation analysis showed that the variables such as: belief in discussion with other farmers about sustainable weed management, the importance of dialogue and implement the recommendations of experts, quality and quantity of extension programs, attitude towards the impact of SWM (Sustainable Weed Management) on healthy crop production and farmers 'attitude toward the effects of this type of management on increasing production has a significant effect on farmers' awareness of integrated weed management in the field The results also showed that farmers' use of appropriate seed (weed-free) and farmers' appropriate attitude toward discussion with other farmers about integrated weed management in the field is the most important variable could be predicted the rice farmers' knowledge of IWM(Integrated Weed Management) in the field. [ABSTRACT FROM AUTHOR]
- Published
- 2020
16. Revolutionizing Demand Response Management: Empowering Consumers through Power Aggregator and Right of Flexibility.
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Alhussein, Sadeq Neamah Bazoon, Barzamini, Roohollah, Ebrahimi, Mohammad Reza, Farahani, Shoorangiz Shams Shamsabad, Arabian, Mohammad, Aliyu, Aliyu M., and Sohani, Behnaz
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SELF-efficacy , *CONSUMERS , *CLEAN energy , *SUSTAINABILITY , *SMART power grids , *ENERGY consumption - Abstract
This paper introduces a groundbreaking approach to demand response management, aiming to empower consumers through innovative strategies. The key contribution is the concept of "acquiring flexibility rights", wherein consumers engage with power aggregators to curtail energy usage during peak-load periods, receiving incentives in return. A flexibility right coefficient is introduced, allowing consumers to tailor their participation in demand response programs, ensuring their well-being. Additionally, a lighting intensity control system is developed to enhance residential lighting network efficiency. The study demonstrates that high-energy consumers, adopting a satisfaction factor of 10, can achieve over 61% in electricity cost savings by combining the lighting control system and active participation in demand response programs. This not only reduces expenses but also generates income through the sale of flexibility rights. Conversely, low-energy consumers can fully offset their expenses and accumulate over USD 33 in earnings through the installation of solar panels. This paper formulates an optimization problem considering flexibility rights, lighting control, and time-of-use tariff rates. An algorithm is proposed for a distributed solution, and a sensitivity analysis is conducted for evaluation. The proposed method showcases significant benefits, including cost savings and income generation for consumers, while contributing to grid stability and reduced blackout occurrences. Real data from a residential district in Tehran validates the method's effectiveness. This study concludes that this approach holds promise for demand response management in smart grids, emphasizing the importance of consumer empowerment and sustainable energy practices. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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17. Revolutionary auxetic intravascular medical stents for angioplasty applications.
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Sadegh Ebrahimi, Mohammad, Noruzi, Mohammad, Hamzehei, Ramin, Etemadi, Ehsan, and Hashemi, Ramin
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RIB cage , *ANGIOPLASTY , *FINITE element method , *UNIT cell - Abstract
[Display omitted] • This study proposes novel auxetic medical stents. • Two-dimensional metamaterials were fabricated through additive manufacturing technique. • Finite element analysis was employed to investigate the mechanical behaviour. • An excellent correlation was observed between the FEA and experimental results. • The modifications made to the rib-unit cells had a significant effect on the stent's recoil behaviour. Due to the significant mortality rate associated with atherosclerosis-induced cardiovascular disease, the utilization of advanced intravascular stents with superior mechanical performance is imperative for the restoration of obstructed arteries. This study proposes novel auxetic medical stents that aim to enhance critical parameters of biomedical stents. This includes load-bearing capacity, expanded opening percentage, and reduced recoil percentage. On this matter, the missing rib auxetic unit cell has been considered and geometrically modified to achieve these objectives. Two-dimensional (2D) metamaterials were fabricated through additive manufacturing technique and subjected to experimental testing. Then, finite element analysis (FEA) was employed to gain comprehensive insights into the mechanical behaviour of the proposed medical stents. Remarkably, an excellent correlation was observed between the FEA and experimental results, validating the high precision of the analysis. The findings reveal that the stents classified as "E-category" exhibit the highest final opening percentage while concurrently demonstrating the lowest recoil percentage. The base stent exhibited a relatively high recoil percentage of 15.56%, indicating a significant amount of recoil or spring-back after deformation. In contrast, the modified "E-category" stent displayed a substantially lower recoil percentage of 1.62%. This notable reduction in recoil percentage indicates that the modifications made to the rib-unit cells had a significant and beneficial effect on the stent's recoil behaviour and minimizing potential damage to arterial tissue during stent deployment (angioplasty) and balloon pressure. The modified design likely enhances the stent's ability to maintain its shape and resist recoil, making it more effective and reliable in its intended application. Additionally, more aspects of biomedical stents such as foreshortening, and dog-boning of the modified missing rib stents were meticulously examined through FEA. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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18. Alternative Approach to Analysis and Design of Series Resonant Converter at Steady State.
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Daryaei, Mohammad, Ebrahimi, Mohammad, and Khajehoddin, Sayed Ali
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CONVERTERS (Electronics) , *NONLINEAR differential equations , *LAPLACE transformation , *ZERO voltage switching , *NONLINEAR theories , *OPTIMAL designs (Statistics) - Abstract
In this paper, new steady-state analysis is proposed for a series resonant converter (SRC) that provides closed-form expressions for converter waveforms. Using the proposed analysis, explicit equations are obtained to design the converter components. It is shown that an SRC can be modeled through a nonlinear differential equation with discontinuous inputs. A Laplace-based theorem (LBT) is provided to obtain the steady-state analytic solution of the resonant converter differential equations. Using the LBT, a flowchart is proposed to analyze the converter where the nonlinearity of differential equation is removed by defining intermediate variables. The variable duty ratio SRC is analyzed using the proposed flowchart. Accurate, closed-form, and explicit equations for converter waveforms, voltage gain, current phase lag, zero voltage switching, and discontinuous conduction mode boundaries are derived. The proposed analysis is compared with conventional methods and its accuracy is validated through simulations and experimental results. Moreover, using the proposed method, a novel procedure is provided for the optimal design of the converter and is compared with conventional design approaches. [ABSTRACT FROM AUTHOR]
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- 2019
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19. Optimal placement of sensors to enhance degrees of freedom in monostatic collocated MIMO radar.
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Ebrahimi, Mohammad, Modarres-Hashemi, Mahmoud, and Yazdian, Ehsan
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MIMO radar , *SENSOR placement , *MONOPULSE radar , *DEGREES of freedom , *ELECTRONIC information resource searching , *DATABASE searching - Abstract
Compared to the traditional monostatic MIMO radar which uses uniform linear arrays (ULAs) for transmitting and receiving signals, sparse linear arrays (SLAs) monostatic MIMO radars can achieve greater Degrees Of Freedom (DOF) and a higher resolution. The optimal placement of sensors in both transmit and receive arrays to attain the maximum DOF is, however, a basic problem in the collocated monostatic MIMO radar. Optimum solution of such a problem is restricted to an exhaustive computer search. Some popular arrays such as nested and coprime arrays have been previously proposed as alternative solutions that can achieve a good DOF, but they do not necessarily lead to the maximum one. In this paper at first, we formulate the optimal placement of sensors in the collocated monostatic MIMO radar to improve the sum coarray as well as the difference coarray of the sum coarray. After that, we present a mathematical framework to achieve the optimal solution for both problems. Finally, we demonstrate that the proposed method yields the optimal MR-MIMO array while demanding much less computational complexity as compared with the computer search. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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20. Performance of rural cooperatives' production in Iran: Implications for sustainable development.
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Akbari, Mohammad, Sadegh Ebrahimi, Mohammad, Amini, Amir Mozafar, Shahzad, Umer, Janečková, Kristina, Sklenička, Petr, Miceikienė, Astrida, and Azadi, Hossein
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SUSTAINABLE development , *COOPERATIVE societies , *INSURANCE companies , *SATISFACTION , *RURAL development - Abstract
One of the most important dimensions of cooperative systems, which have existed in Iran since 1974, is cooperative rural production enterprises. In this study, the performance of rural production cooperatives in Iran is examined in relation to the social capital components of the members. This study's statistical population consisted of 16,870 members from 41 cooperatives. 217 samples of cooperative members and 98 samples of the cooperative's management and board of directors were selected using the Cochran formula, and questionnaires were filled out for each group. The results showed that from the viewpoint of the members of rural cooperatives, the most important factor in improving the performance of cooperatives was the use of effective extension training (model-extension sites). The results also showed that members' satisfaction and training members of cooperatives can play an important role in improving the performance of cooperatives. The results of this research, while emphasizing the role of education (especially extension activities), can help rural development planners in improving the performance of rural cooperatives in their regions. [Display omitted] • The study identified the impacts of social capitals on the performance of rural production cooperatives. • The most important factor in improving the performance was the use the extension trainings. • Members' satisfaction and training play an important role in improving the performance. • The level of education in production cooperatives has a direct relationship with trust and satisfaction. • Cooperatives do not perform well in the fields of sales, marketing and insurance. [ABSTRACT FROM AUTHOR]
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- 2023
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21. Methods and applications of new technologies used for reducing of chemical usage and controlling of pests (a review).
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Ebrahimi, Mohammad Ali, Khoshtaghaza, Mohammad Hadi, Minaei, Saeid, and Jamshidi, Bahareh
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PESTICIDES , *AGRICULTURAL chemicals , *INTEGRATED pest control , *PLANT protection , *FOOD industry - Abstract
Initial low cost of pesticides and lack of knowledge on the part of agricultural producers has led to an overuse of pesticides, with dangerous consequences. On the other hand, today, pesticides have an important role in the increment of agriculture products. Therefore, in recent years, the major aims of agricultural, environmental and even the food industry researchers have been to reduce the usage of chemical materials in agricultural applications. To achieve this, variable rate application in sprayers using different technologies such as machine vision, ultrasonic sensors, spectrometry, laser scanning, as well as pest identification and classification, have been applied in recent studies. This paper reviews these works reported in the 21 century. In addition, the best result is suggested in the conclusion section for future studies. [ABSTRACT FROM AUTHOR]
- Published
- 2018
22. Work-Related Stress Dimensions Among A Subsidiary Company Workers of Iranian Oil Refining And Distribution Company.
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SHatti, Mahboobeh, Ebrahimi, Mohammad Hossein, Gharibi, Vahid, and Malakouti, Javad
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JOB stress , *PETROLEUM refineries , *PETROLEUM workers , *SUBSIDIARY corporations , *QUALITY of work life - Abstract
Introduction Work-related stress and its causes are among the most important issues which can seriously challenge organizational efficiency and employees' health. Different occupational environments and groups have different levels of job stress. The present study aimed to investigate relationships between job stress and its dimensions with three occupational groups (administrative, administrative-operational, and operational) among a subsidiary company workers of Iranian Oil Refining and Distribution Company. Methods The present study had descriptive-analytical and cross-sectional type and was conducted among 468 out of 503 employees (with entry condition of a year of work experience as well as an official and contractual membership) volunteered to participate in research. Data collection tools included demographic questions and job stress questionnaire as well as human resource department information to determine occupational group of employees. Descriptive statistics, statistical tests, Independent test, and oneway ANOVA in addition to SPSS 21 software were used for data analysis. Results There were significant relationships between age, education levels, work experience and smoking with mean score of job stress (P-value <0.05). Mean score of employees' job stress in operational occupation group was significantly higher than other two occupational groups (P-value=0.004), and there were significant relationships between employees' occupational group variables with five dimensions of job stress (demand, relationships and role, managerial support, and peer support) (P-value<0.05). There were not any significant relationships between other variables and job stress (Pvalue> 0.05). Conclusions Exposure to different occupational harmful agents, facing with different safety risks, being far from family, heavy workload, and uncertain employee roles have significantly increased job stress in both operational and executive occupation groups compared to other two occupational groups; hence, there is a positive correlation between high job stress and operational jobs. [ABSTRACT FROM AUTHOR]
- Published
- 2018
23. Instantaneous Torque Control Method With Rated Torque-Sharing Ratio for Cascaded DFIMs.
- Author
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Esfandiari, Ghasem, Ebrahimi, Mohammad, and Tabesh, Ahmadreza
- Subjects
- *
TORQUE control , *INDUCTION motors , *ELECTRIC power , *DIRECT currents , *SIMULATION methods & models - Abstract
This paper presents an instantaneous torque control method for cascaded doubly fed induction machines (CDFIMs) with a rated torque-sharing ratio feature under steady-state operation. A CDFIM includes two coupled main and auxiliary doubly fed induction machines, and the rated torque-sharing ratio herein means that the machine torques are proportional to the machine ratings. The proposed method is established based on transferring the torque equations of the two machines into the rotor-flux reference frame of the auxiliary machine. Then, the instantaneous torque and the rated torque-sharing ratio are controlled via the stator current components of the auxiliary machine, while machine fluxes are within allowable ranges. To verify the method and evaluate its capabilities, the suggested method is used for the speed control of a CDFIM experimental setup including two 4-kW doubly fed induction machines and a 4-kW dc machine to apply a sudden mechanical load change to the CDFIM. Further, a case study including 12-kW and 4-kW DFIMs is also simulated to evaluate the performance of the torque control method for a CDFIM with different machine ratings. The test results confirm that the proposed control schemes achieve the desired performances without exceeding the ratings of the machines under various test scenarios. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
24. Complex Delta–Sigma-Based Transmitter With Enhanced Linearity Performance Using Pulsed Load Modulation Power Amplifier.
- Author
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Jouzdani, Maryam, Ebrahimi, Mohammad Mojtaba, Helaoui, Mohamed, and Ghannouchi, Fadhel M.
- Subjects
- *
CODING theory , *DELTA-sigma modulation , *GSM communications , *LONG-Term Evolution (Telecommunications) , *SIGNAL quantization , *IEEE 802.16 (Standard) - Abstract
This paper proposes a linear and efficient transmitter prototype based on pulsed load modulation (PLM) power amplifier (PA). The proposed transmitter setup utilizes the complex delta–sigma (DS) modulation as a signal processing technique instead of the envelope DS modulation for higher linearity performance. Using the complex DS modulation technique reduces the in-band quantization noise significantly at the output of the modulator and consequently, enhances the linearity of the transmitter. To validate the proposed technique, the linearity and efficiency performance of the complex DS modulator (CDSM)-based transmitter are compared with the performance of its envelope DS modulator (EDSM) counterpart in measurement. For this paper, an efficient and linear PLM PA is designed and fabricated using GaAs E-pHEMT transistors. For a Long-Term Evolution (LTE) uplink standard signal with 3-MHz bandwidth and 7-dB peak-to-average power ratio, the CDSM-based transmitter achieves the drain efficiency and power added efficiency of 46% and 42%, respectively, at an average output power of 25.1 dBm. The comparison measurement study of EDSM-based transmitter and the CDSM-based transmitter with the LTE uplink signal shows about 11-dB improvement in the signal-to-noise and distortion ratio of the output signal. The measurement results for LTE signals were able to pass the spectral requirements defined by the standard without applying predistortion techniques. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
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25. Fixed Switching Frequency Generalized Peak Current Control (GPCC) of DC?AC Converters.
- Author
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Ebrahimi, Mohammad and Khajehoddin, S. Ali
- Subjects
- *
DC-AC converters , *ELECTRIC current converters , *ELECTRIC currents , *PULSE width modulation , *PULSE modulation - Abstract
A fast and robust fixed switching frequency peak current controller for DC–AC converters is presented. The proposed method tends to mimic the switching behavior of pulse width modulation (PWM) techniques, so it features all the advantages of peak current controllers (such as simplicity, fast transient, and optimum dynamic response), with the superiority of fixed switching frequency and harmonic free output. The proposed method is a generalized approach that can be applied to different PWM schemes. The method is specifically elaborated for single-phase distributed generation applications, using various inverter topologies and mimicking different PWM schemes. Moreover, adaptive bands are proposed to provide active damping for the controller, to extend use of the proposed method for inverters with LCL output filters. Feasibility and performance of the controller is shown by means of simulations and experiments. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
26. Using microsatellite markers to analyze genetic diversity in 14 sheep types in Iran.
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Ebrahimi, Mohammad Taghi Vajed, Mohammadabadi, Mohammadreza, and Esmailizadeh, Ali
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LIVESTOCK , *SHEEP , *ANIMAL genetics - Abstract
Investigation of genetic relationship among populations has been traditionally based on the analysis of allele frequencies at different loci. The prime objective of this research was to measure the genetic polymorphism of five microsatellite markers (McMA2, BM6444, McMA26, HSC, and OarHH35) and study genetic diversity of 14 sheep types in Iran. Genomic DNA was extracted from blood samples of 565 individuals using an optimized salting-out DNA extraction procedure. The polymerase chain reaction (PCR) was successfully performed with the specific primers. Some locus-population combinations were not at Hardy-Weinberg equilibrium (P < 0:05). The microsatellite analysis revealed high allelic and gene diversity in all 14 breeds. Pakistani and Arabi breeds showed the highest mean number of alleles (11.8 and 11 respectively), while the highest value for polymorphic information content was observed for the Arabi breed (0.88). A UPGMA (unweighted pair group method with arithmetic mean) dendrogram based on the Nei's standard genetic distance among studied breeds showed a separate cluster for Arabi and Pakistani breeds and another cluster for other breeds. The Shannon index (H0) for McMA2, BM6444, McMA26, HSC, and OarHH35 was 2.31, 2.17, 2.27, 2.04 and 2.18, respectively, and polymorphic information content (PIC) values were 0.88, 0.92, 0.87, 0.84, and 0.86 for McMA2, BM6444, McMA26, HSC, and OarHH35, respectively. The high degree of variability demonstrated within the studied sheep types implies that these populations are rich reservoirs of genetic diversity that must be preserved. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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27. Interfering With Lipid Raft Association: A Mechanism to Control Influenza Virus Infection By Sambucus Nigra.
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Shahsavandi, Shahla, Ebrahimi, Mohammad Majid, and Farahani, Ameneh Hasaninejad
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THERAPEUTIC use of European elder , *LIPID rafts , *INFLUENZA prevention , *INFLUENZA treatment , *DRUG efficacy , *REVERSE transcriptase polymerase chain reaction - Abstract
Sambucus nigra (elder) are broadly used species to treat microbial infections. The potential antiviral activity and mechanism action of elder fruit (EF) in human epithelium cell (A549) cultures infected with H9N2 influenza virus were determined. The effect of various concentrations of EF on influenza virus replication was examined by using virus titration, quantitative real time RT-PCR, fusion and lipid raft assays following two treatment procedures: A) pre-treated H9N2 virus with each concentration of EF extract and transfection of A549 cell cultures, and B) each concentrations of EF was added to H9N2 virus infected-cell cultures following virus adsorption. In both treatments with lower doses of EF increased viral titer as well as synthesized viral nucleoprotein as indicating the herb had no inhibitory effects on virus replication. In (B) trial with higher doses, 40 and 80 µg/mL of EF, a significant decrease in virus titer and viral protein synthesis were shown in EF treated cells indicating the herb affect either entry of viruses or inhibition virus particle release. The results suggest that EF treatment of the influenza virus infected-human epithelial cells may involve in lipid raft association which function as platform for formation of viral membrane fusion and budding. Differencesin treatment time and dose of EF extract in infected cells with influenza virus have a marked effect on the efficacy of the herb. [ABSTRACT FROM AUTHOR]
- Published
- 2017
28. SENSIBle: A Highly Scalable SENsor DeSIgn for Path-Based Age Monitoring in FPGAs.
- Author
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Ghaderi, Zana, Ebrahimi, Mohammad, Navabi, Zainalabedin, Bozorgzadeh, Eli, and Bagherzadeh, Nader
- Subjects
- *
DETECTORS , *FIELD programmable gate arrays - Abstract
This paper proposes a highly scalable sensor design for late transition detection in FPGA based platforms. Transition delays occur because of aging mechanisms such as Biased Temperature Instability (BTI) and Hot Carrier Injection (HCI). We propose a sensor clock (SCLK) that is a function of minimum slack time of a set of paths selected for age monitoring. There will be one such clock for many sensors as are needed in an entire FPGA. Our proposed sensor architecture makes it possible for a single SCLK to be shared by all sensors. Additionally, the proposed sensor occupies one slice (basic FPGA logic block), which leads to low area, power, and performance overhead. Using Artix-7-based board, experimental results demonstrate that the proposed aging sensor detects aging earlier than existing sensors and provides less power and performance overheads. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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- View/download PDF
29. The investigation of laser shock peening effects on corrosion and hardness properties of ANSI 316L stainless steel.
- Author
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Ebrahimi, Mohammad, Amini, Saeid, and Mahdavi, Seyed
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LASER peening , *MECHANICAL behavior of materials , *STAINLESS steel corrosion , *HARDNESS , *SHOCK waves - Abstract
Laser shock peening (LSP) is known as a post processing surface treatment which can improve the mechanical properties of some materials. Shock waves are generated by confining the laser-induced plasma to cause a large pressure shock wave over a significant surface area. In the present study, effects of LSP on the electrochemical corrosion and micro hardness properties of 316L stainless steel alloy were investigated by changing the laser parameters such as the laser spot size, the average number of impacts, and the laser intensity. Since laser parameters do not cover the desired region of LSP, we have to use the proper design of experiment method, in which the D-optimal design of MATLAB was selected. Results revealed that by increase in irradiance, number of impacts and spot size of laser beam, improvement in the surface micro hardness, and corrosion resistance is achieved. Also, due to unexpected drop into the outcome of our experiments, it was found that the contamination of the transparent overlay and reduction of the absorption coefficient of the absorbent layer play a key role to reduce the efficiency of the mechanical impacts. So, by changing the experimental conditions, even better results are expected. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
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30. Relationship between occupational stress and cardiovascular diseases risk factors in drivers.
- Author
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BIGLARI1, HAMED, EBRAHIMI, MOHAMMAD HOSSEIN, SALEHI, MARYAM, POURSADEGHIYAN, MOHSEN, AHMADNEZHAD, IMAN, ABBASI, MILAD, and Biglari, Hamed
- Subjects
- *
JOB stress , *CARDIOVASCULAR diseases , *DISEASES , *INDUSTRIAL psychology , *MOTOR vehicle drivers , *BLOOD sugar analysis , *AUTOMOBILE driving , *BLOOD pressure , *LIPIDS , *SMOKING , *PSYCHOLOGICAL stress , *OCCUPATIONAL hazards , *ENVIRONMENTAL exposure , *CROSS-sectional method , *PSYCHOLOGICAL factors - Abstract
Objectives: Of all work stressors, occupational stress is the leading cause of many disorders among workers. Drivers are classified as a high risk group for work related stress. This study set out to determine the relationship between risk factors of cardiovascular diseases and occupational stress among drivers.Material and Methods: Two hundred and twenty two Ilam's intercity drivers were selected for the study. For measuring work stress, the Osipow work stress questionnaire was used. After a 10-h fasting period, systolic and diastolic blood pressure was recorded. Intravenous blood samples were taken to determine cholesterol, triglyceride and blood glucose levels. The independent samples t-test and Pearson's correlation test were used to assess the relationship between variables and occupational stress.Results: Seventy-one percent of the intercity drivers suffered from average to acute stress, and 3.1% of them suffered from acute stress. There was no significant relationship between occupational stress and diastolic blood pressure (p = 0.254) among the drivers. Nevertheless, the Pearson's correlation test demonstrated a strong relationship between work stress and blood glucose (p < 0.01), while no strong correlation was found for blood triglycerides and cholesterol levels.Conclusions: Based on the results, high rates of occupational stress were observed in the Ilam's intercity drivers. Occupational stress may have effect on blood glucose levels but the results did not suggest a considerable relationship between risk factors of cardiovascular diseases and occupational stress among intercity drivers. Int J Occup Med Environ Health 2016;29(6):895-901. [ABSTRACT FROM AUTHOR]- Published
- 2016
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31. A novel approach to investigation of the pathogenesis of pterygium based on assessment of promoter hyper-methylation and expression profile of CTLA4 gene: A credible report of CTLA4 gene expression in human eye tissue.
- Author
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Ebrahimi, Mohammad Essmail, Kordi-Tamandani, Dor Mohammad, and Arish, Mohammed
- Subjects
- *
PTERYGIUM , *CYTOTOXIC T lymphocyte-associated molecule-4 , *METHYLATION , *GENE expression , *EYE physiology , *OCULAR injuries , *DISEASE prevalence - Abstract
Background Pterygium is the human eye lesion whose prevalence in the general population is estimated about 2%. The disease, in extreme phase, can lead to visual disturbance and eventually causes complete loss of vision due to the lesion growth over the papillary axis. Pterygium invasive tissue is a tumor-like tissue that is initially identified and then is attacked by cytotoxic T cells. Cytotoxic T lymphocyte associated antigen 4 (CTLA4), as a modulator molecule of the adaptive immune system, plays a critical role in maintaining peripheral T cell tolerance by diminishing its responsiveness and increasing its activation threshold. The aim of this study is to investigate the association between some epigenetic changes of the CTLA4 gene, such as promoter methylation and gene expression, and pathogenesis of pterygia. Materials and methods Genomic DNA was extracted from 75 formalin-fixed, paraffin-embedded tissues of pterygia and 70 specimens of normal conjunctiva from eyes without pterygium as the control group, collected from Sistan and Baluchestan population. CTLA4 gene promoter methylation was carried out by methylation-specific PCR technique. The gene expression analysis was done on extracted total RNA from 20 healthy and 23 pterygium tissue samples using Real-Time PCR technique. Results Promoter methylation changes of CTLA4 gene were not statistically different in patients with pterygium in comparison with healthy controls (OR = 1.614; 95% CI = 0.57–4.75; P value = 0.37). However, gene expression level of CTLA4 was remarkably different in patients and healthy controls (Mean ± SD: 1.343 ± 0.133 and 2.027 ± 0.219, respectively; P value = 0.009). Conclusion This is a credible evidence of CTLA4 gene expression in human eye tissue. This first hand attempt of investigating the association of epigenetic changes of the CTLA4 gene and pathogenesis of pterygia, indicated a significant intensification of the gene expression of CTLA4 in patients with pterygia. We suggest that increasing CTLA4 gene expression can be a trigger which promotes pterygium enlargement. However, further studies on more populations with larger sample sizes need to be done to verify this hypothesis in the future. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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32. Fast and Robust Single-Phase $DQ$ Current Controller for Smart Inverter Applications.
- Author
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Ebrahimi, Mohammad, Khajehoddin, Sayed Ali, and Karimi-Ghartemani, Masoud
- Subjects
- *
ELECTRIC inverters , *ROBUST control , *ELECTRIC currents , *VOLTAGE control , *LOW voltage systems - Abstract
This paper presents a fast and robust $DQ$ current controller to regulate the output power of single-phase grid-connected inverters. The proposed method generates the grid current orthogonal component without introducing any additional dynamics or distortions to the control loop. Moreover, its operation does not depend on the system parameters. The proposed method exhibits improved steady-state and dynamic performances in comparison with the inverters equipped with the conventional orthogonal signal generation techniques. Its improved characteristics make the proposed controller suitable for smart inverter applications, to provide advanced grid functionalities as demanded by recently revised standards. Simulation and experimental results show the feasibility and performance of this control structure. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
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33. Expression of Factor X in BHK-21 Cells Promotes Low Pathogenic Influenza Viruses Replication.
- Author
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Shahsavandi, Shahla, Ebrahimi, Mohammad Majid, Masoudi, Shahin, and Izadi, Hasan
- Subjects
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INFLUENZA viruses , *VIRAL replication , *GENE expression , *SERINE , *ANTISENSE DNA , *MOLECULAR cloning , *CHICKEN embryos - Abstract
A cDNA clone for factor 10 (FX) isolated from chicken embryo inserted into the mammalian cell expression vector pCDNA3.1 was transfected into the baby hamster kidney (BHK-21) cell line. The generated BHK-21 cells with inducible expression of FX were used to investigate the efficacy of the serine transmembrane protease to proteolytic activation of influenza virus hemagglutinin (HA) with monobasic cleavage site. Data showed that the BHK-21/FX stably expressed FX after ten serial passages. The cells could proteolytically cleave the HA of low pathogenic avian influenza virus at multiplicity of infection 0.01. Growth kinetics of the virus on BHK-21/FX, BHK-21, and MDCK cells were evaluated by titrations of virus particles in each culture supernatant. Efficient multicycle viral replication was markedly detected in the cell at subsequent passages. Virus titration demonstrated that BHK-21/FX cell supported high-titer growth of the virus in which the viral titer is comparable to the virus grown in BHK-21 or MDCK cells with TPCK-trypsin. The results indicate potential application for the BHK-21/FX in influenza virus replication procedure and related studies. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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- View/download PDF
34. Dynamic Modeling and Analysis of Cascaded DFIMs in an Arbitrary Reference Frame.
- Author
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Esfandiari, Ghasem, Ebrahimi, Mohammad, Tabesh, Ahmadreza, and Esmaeilzadeh, Mohammad
- Subjects
- *
DYNAMIC models , *INDUCTION machinery , *FRAMES of reference (Relativity) , *ELECTRIC circuits , *ELECTRIC machinery rotors - Abstract
This paper presents a comprehensive investigation of various reference frames and their relative speeds in cascaded doubly-fed induction machines (CDFIMs). Then, a compact space-phasor model of CDFIMs in the natural and arbitrary reference frames is presented that is useful for performance analysis of CDFIMs based on rotating phasors. The merits of the proposed model compared with existing models are using a common (single) reference frame for all machines and parts of CDFIMs, and the model formulation is independent of the rotor angle position. The reference frames in the suggested model can be fixed on the common rotor of the CDFIM machines for dynamic analysis or it can be fixed on the stator/rotor flux of each cascaded machines useful for CDFIMs controller design. A two-axes equivalent circuit for a CDFIM is also presented, which enables analysis of CDFIMs in commercially available power circuit simulation software tools. The validity of the model is verified via the investigation of an experimental setup and consists of two mechanically coupled 4-kW DFIMs and a 4-kW dc machine as a load. The setup is investigated under various test scenarios, including free acceleration, load (torque) change, and frequency step change conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
35. Sensorless anti-swing control for overhead crane using voltage and current measurements.
- Author
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Gholabi, Amin, Ebrahimi, Mohammad, Yousefi, Gholam Reza, Ghayour, Mostafa, Ebrahimi, Ali, and Jali, Hamed
- Subjects
- *
SENSORLESS control systems , *CRANES (Machinery) , *INCLINOMETER , *INDUSTRIAL noise , *INDUCTION motors , *PENDULUMS - Abstract
One of the most critical issues in overhead cranes is the swing of a suspended load while the crane starts to move and accelerates, changes the movement direction, breaks or stops. This can lead to severe damage, and therefore several methods have been applied to damp the load swings. Most of these methods are based on information about the swing angle of a suspended load. In traditional methods, camera vision, acceleration or inclinometers sensors, simple pendulums and other types of sensors have been used. Generally, a method is desired if it can estimate the swing angle with the least equipment costs, while using an uncomplicated calculation method and the minimum sensitivity to environmental situations and industrial noises. In this paper, a new algorithm is proposed to estimate the swing angle. To do so, the supplied voltage and current of the induction motor which drives the trolley are measured, and then using a new proposed method based on a dynamic analysis of the mathematical dynamic model, the swing angle is estimated and is used in the controller system to damp the swings. The proposed method is verified by means of computer simulations. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
36. Sleep habits and road traffic accident risk for Iranian occupational drivers.
- Author
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EBRAHIMI, MOHAMMAD HOSSEIN, SADEGHI, MASOUMEH, DEHGHANI, MOHSEN, and NIIAT, KHOSRO SADEGH
- Subjects
- *
HEALTH , *SLEEP , *TRAFFIC engineering , *QUESTIONNAIRES , *DEMOGRAPHIC change , *AUTOMOBILE driving , *COMPARATIVE studies , *WORK-related injuries , *RESEARCH methodology , *MEDICAL cooperation , *RESEARCH , *SLEEP apnea syndromes , *SMOKING , *SNORING , *TRAFFIC accidents , *EVALUATION research , *DISEASE prevalence - Abstract
Objectives: The aim of this study is to assess the sleep quality and sleep disorders (prevalence of obstructive sleep apnea and sleepiness) among occupational drivers in Iran and to determine which demographic factors and occupational habits are linked to road traffic accidents.Material and Methods: In this analytic cross-sectional study 556 occupational road drivers from Shahroud city (in the northeast of Iran) participated, upon a prior verbal informed consent, during 2013-2014. The Pittsburgh Sleep Quality Index (PSQI) standard questionnaire that scored on 7 point scale, the 8-item Epworth Sleepiness Scale (ESS) questionnaire and the 8-question STOP-Bang questionnaire along with demographic information and occupational data were used. To explore the independent factors associated with odds of poor sleep quality and road accident, multiple logistic regression models were used.Results: Prevalence of previous road accidents, sleepiness while driving, and obstructive sleep apnea scored ≥ 3 in the study, and drivers accounted for 23.8%, 29%, and 24.8%, respectively. The global mean score of sleep quality and excessive sleepiness score were 5.2 and 4.8, respectively. The main factors related to the odds of poor sleep quality were snoring (odds ratio (OR) = 2.34; 95% confidence interval (CI): 1.15-4.77), smoking (OR = 2.12; 95% CI: 1.15-3.97), and driving times in a day (OR = 1.12; 95% CI: 1.03-1.21). The Epworth Sleepiness Scale (OR = 1.13; 95% CI: 1.07-1.23) and suffering from apnea (OR = 4.89; 95% CI: 1.07-23.83) were the best predictors for odds (increased risk) of road accidents.Conclusions: A considerable proportion of Iranian drivers had records of road accidents; poor sleep quality, sleepiness while driving, and sleep disorder breathing (obstructive sleep apnea - OSA). Snoring, smoking, driving time in a day, excessive sleepiness, and presumably apnea increase the odds of poor sleep quality and road traffic accident for Iranian occupational drivers. [ABSTRACT FROM AUTHOR]- Published
- 2015
- Full Text
- View/download PDF
37. Reducing Quantization Noise to Boost Efficiency and Signal Bandwidth in Delta–Sigma-Based Transmitters.
- Author
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Ebrahimi, Mohammad Mojtaba and Helaoui, Mohamed
- Subjects
- *
BANDWIDTH allocation , *TRANSMITTERS (Communication) , *CODING standards (Coding theory) , *SIGNAL quantization , *ELECTRIC distortion , *NOISE generators (Electronics) , *EQUIPMENT & supplies - Abstract
This paper introduces two new techniques to enhance both efficiency and signal bandwidth in delta–sigma-based transmitters. At first step, a technique called quantization noise reduction (QNR), is introduced to enhance the coding efficiency. By filtering out part of the quantization noise in the whole band of the signal, while the signal envelope is maintained almost constant, the coding efficiency is improved without imposing any additional nonlinearity or distortion to the system. By utilizing this technique for an orthogonal frequency division multiplexing (OFDM) signal with 1.25-MHz bandwidth and 80 times oversampling, with 8.1-dB peak-to-average power ratio (PAPR), the coding efficiency is improved from 8.8% to 14.5% while the signal-to-noise distortion ratio (SNDR) of the system remains 43 dB. In the next step by using a controlled filtering on in-band quantization noise along with QNR technique, the bandwidth of the signal and efficiency are increased simultaneously without losing as much linearity. The second technique is called quantization noise reduction with in-band filtering or (QNRIF). QNRIF is applied on an OFDM signal with 1.25-MHz bandwidth, with the same PAPR and only 16 times oversampling. The result for the coding efficiency is improved from 7.7% to 18.7% with 41-dB SNDR. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
38. Envelope Tracked Pulse Gate Modulated GaN HEMT Power Amplifier for Wireless Transmitters.
- Author
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Jouzdani, Maryam, Ebrahimi, Mohammad Mojtaba, Rawat, Karun, Helaoui, Mohamed, and Ghannouchi, Fadhel M.
- Subjects
- *
TRANSMITTERS (Communication) , *POWER amplifiers , *MODULATION-doped field-effect transistors , *GALLIUM nitride , *IEEE 802.16 (Standard) , *DELTA-sigma modulation - Abstract
This paper proposes a complete transmitter prototype for wireless applications using envelope tracked pulsed gate modulated power amplifier (PA). The proposed transmitter architecture is developed using two high power 10 W gate modulated PAs combined in a fashion to operate as a switched voltage source for the range of duty cycles of pulses driving the gates of power amplifiers. These PAs are designed and implemented using packaged GaN HEMT transistors from CREE to operate at the carrier frequency of 2.35 GHz. For a 5 MHz bandwidth WiMAX 802.16e down-link signal with the PAPR of 7.9 dB and the oversampling ratio of 100, the average drain efficiency of 46.2% is achieved at the average output power of 35.8 dBm. Using a 5 MHz bandwidth LTE down-link signal with 11 dB PAPR and centered at 2.35 GHz, the power amplifier delivers the average output power of 33.2 dBm with the average drain efficiency of 46%. The adjacent channel leakage ratio (ACLR) measured for this signal is less than -36.85 dBc at 10 MHz offset from the center frequency of 2.35 GHz. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
39. Dose- and Time-Dependent Apoptosis Induced by Avian H9N2 Influenza Virus in Human Cells.
- Author
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Shahsavandi, Shahla, Ebrahimi, Mohammad Majid, Sadeghi, Kaveh, Mosavi, Seyedeh Zahra, and Mohammadi, Ashraf
- Abstract
To understand human response to avian H9N2 influenza, we investigated the effects of the viral infection on A549, HepG2, and HeLa cells at low and high MOIs. To identify virus-host interplay, expression of Mx and NP genes was measured in the cells supernatants. Cell viability and apoptosis were evaluated by MTT assay, DNA fragmentation, and florescent staining. The virus titration and NP gene transcript levels indicate lower susceptibility of HeLa cell to H9N2 replication than other cells. Although H9N2 did produce a faster CPE in HepG2, high dose of the virus induced apoptosis within early stage of A549 infection. The DNA laddering was enhanced in the cell correlated with increase in virus transcripts. The undetectable to different regulation levels of Mx gene were observed in response to H9N2 infection suggesting that an insufficient antiviral defense in the noncompetent-IFN HepG2 cell promotes efficient viral replication. These results showed that the permissivity of HepG2 for H9N2 is comparable with A549; however, liver cells are not target tissue respond to the infection. These data revealed that the H9N2 virus induced apoptosis signaling via mitochondrial pathway in human alveolar epithelial cells, indicating that the induction may be associated with a dose-dependent manner. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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- View/download PDF
40. Synthesis of High Aspect Ratio Platelet SrTiO3.
- Author
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Ebrahimi, Mohammad E., Allahverdi, Mehdi, and Safari, Ahmad
- Subjects
- *
TITANIUM dioxide , *CERAMICS , *RUTILE , *INDUSTRIAL chemistry , *MATERIALS science - Abstract
A method for synthesis of high aspect ratio platelet seeds by growth of SrTiO3 on Sr3Ti2O7 core particles is reported. The aim of this study was to identify and control the morphology and size of SrTiO3 particles via molten salt synthesis. Platelet and tabular morphologies with rectangular faces were obtained using rutile and anatase, respectively. Platelet SrTiO3 particles with an edge length of 10–40 μm and a thickness of 1–4 μm were obtained. High aspect ratios (edge length to thickness) of 7–10 were measured for platelet particles as opposed to lower aspect ratios of 2–4 for tabular particles. Highly anisotropic platelets are suitable template candidates to achieve textured ceramics. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
41. A Review on Ionic Liquids-Based Membranes for Middle and High Temperature Polymer Electrolyte Membrane Fuel Cells (PEM FCs).
- Author
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Ebrahimi, Mohammad, Kujawski, Wojciech, Fatyeyeva, Kateryna, and Kujawa, Joanna
- Subjects
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PROTON exchange membrane fuel cells , *HIGH temperatures , *ION-permeable membranes , *THERMAL conductivity , *POLYELECTROLYTES , *POLYMERIC membranes , *SOLID state proton conductors - Abstract
Today, the use of polymer electrolyte membranes (PEMs) possessing ionic liquids (ILs) in middle and high temperature polymer electrolyte membrane fuel cells (MT-PEMFCs and HT-PEMFCs) have been increased. ILs are the organic salts, and they are typically liquid at the temperature lower than 100 °C with high conductivity and thermal stability. The membranes containing ILs can conduct protons through the PEMs at elevated temperatures (more than 80 °C), unlike the Nafion-based membranes. A wide range of ILs have been identified, including chiral ILs, bio-ILs, basic ILs, energetic ILs, metallic ILs, and neutral ILs, that, from among them, functionalized ionic liquids (FILs) include a lot of ion exchange groups in their structure that improve and accelerate proton conduction through the polymeric membrane. In spite of positive features of using ILs, the leaching of ILs from the membranes during the operation of fuel cell is the main downside of these organic salts, which leads to reducing the performance of the membranes; however, there are some ways to diminish leaching from the membranes. The aim of this review is to provide an overview of these issues by evaluating key studies that have been undertaken in the last years in order to present objective and comprehensive updated information that presents the progress that has been made in this field. Significant information regarding the utilization of ILs in MT-PEMFCs and HT-PEMFCs, ILs structure, properties, and synthesis is given. Moreover, leaching of ILs as a challenging demerit and the possible methods to tackle this problem are approached in this paper. The present review will be of interest to chemists, electrochemists, environmentalists, and any other researchers working on sustainable energy production field. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
42. Pregnancy outcomes in women with Celiac disease in Northeast Iran: a regional retrospective cohort study.
- Author
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Sahebdel, Saeed, Ganji, Azita, Nezhad Baei, Sajedeh Alijan, Amirian, Malihe, Farkhani, Ehsan Mousa, Ebrahimi, Mohammad, Nazar, Eisa, Khojastehnezhad, Mohammad Amin, and Valizadeh, Sadaf
- Subjects
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PREGNANCY outcomes , *CELIAC disease , *GESTATIONAL diabetes , *PREMATURE labor , *REPRODUCTIVE technology , *INDUCED labor (Obstetrics) - Abstract
Purpose: To investigate the odds and associations of pregnancy outcomes with exposure to biopsy-confirmed celiac disease (CD) in Northeast Iran. Methods: In this regional retrospective cohort study, pregnancy records of all women with celiac disease who visited Celiac Disease Clinic of Imam-Reza Hospital from 2017 to 2023 (exposed group) and a sample of women without CD (unexposed group) were extracted using the Electronic Health Record of Mashhad University of Medical Sciences called "Sina". The unexposed group was randomly selected of the database and matched to exposed group on age, location of residence, socioeconomic factors. Our exclusion criteria included age ≥ 45, presence of concomitant disorders, history of non-obstetric uterine surgery, induction of pregnancy through assisted reproductive technology, and any concurrently ongoing pregnancy at the time of study. Pregnancy outcomes evaluated in this study included normal delivery, miscarriage, preterm labor, preeclampsia, and stillbirth. Adjusted odds ratios were calculated using logistic regression adjusted for confounders. Results: Ninety pregnancy records of women with CD and 270 pregnancies of women without CD were included in this study. Low neonatal birthweight (i.e. under 2500 g) had no significant association with CD (aOR = 0.99, 95% CI = 0.92–1.06), as well as postpartum hemorrhage (aOR = 1.12, 95%CI = 0.91–1.38), fetal anomaly (aOR = 0.89, 95%CI = 0.69–1.15), miscarriage (aOR = 1.00, 95%CI = 0.91–1.10), ectopic pregnancy (aOR = 0.94, 95%CI = 0.73–1.20), preterm labor (aOR = 1.00, 95%CI = 0.92–1.10), gestational diabetes mellitus (aOR = 1.07, 95%CI = 0.98–1.16), gestational hypertension (aOR = 0.99, 95%CI = 0.89–1.11), and gestation hypothyroidism (aOR = 0.95, 95%CI = 0.82–1.11). However, we found significantly lower odds of preeclampsia in pregnancies affected by CD (aOR = 0.83, 95%CI = 0.69–0.99). Conclusion: Celiac disease was not associated with increased odds of low neonatal birthweight, postpartum hemorrhage, fetal anomaly, miscarriage, ectopic pregnancy, preterm labor, gestational diabetes mellitus, gestational hypertension and gestational hypothyroidism. Preeclampsia had significantly lower odds in pregnancies affected with CD. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
43. Determination of the most effective control methods of SO2 Pollution in Tehran based on adaptive neuro-fuzzy inference system.
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Ebrahimi, Mohammad and Qaderi, Farhad
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FUZZY systems , *VORONOI polygons , *GASOLINE , *AIR pollution control , *FUZZY neural networks , *STANDARD deviations , *SULFUR dioxide - Abstract
Air pollution in metropolises is one of the serious problems of human life. Tehran is one of the cities facing air pollution problem. Urban managers concern about choosing different management methods to control air pollution. In this study, a combination of fuzzy systems and neural networks has been used to select the most suitable scenario for controlling SO 2 pollution. According to the method presented in this paper, 8 input data categories such as wind speed, precipitation, temperature, pressure, humidity, gas oil consumption, gasoline consumption and urban green space levels have been used as independent parameters and SO 2 pollutant concentration has been considered as the dependent parameter. The contribution of each meteorological station to the meteorological data was determined by Thiessen Polygon Method. Then, using adaptive neural fuzzy inference systems, modeling was done in Sugeno Method and the least root mean square error (3.19) was determined for the model. Then, by changing each of the independent parameters, the effect of each of these independent parameters on SO 2 pollutant was measured. The results showed that the parameters of pressure, urban green space, gasoline consumption, gas oil consumption, temperature, wind speed and humidity, respectively, had the greatest effect on reducing the SO 2 concentration. Since the parameters of gasoline and gas oil consumption as well as the area of green space are changeable by different policies and by human decisions, the concentration of SO 2 pollutant can be controlled by reducing the consumption of gasoline and gas oil and increasing the green space in Tehran. • Finding the lowest error rate in any of the models predicting sulfur dioxide concentration. • Determine the effect of each of the independent parameters on the concentration of SO 2. • Determination of the best predictive model for sulfur dioxide emissions based on ANFIS model. • Providing solutions to improve air pollution. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
44. Peripheral nerve regeneration in rats by chitosan/alginate hydrogel composited with Berberine and Naringin nanoparticles: in vitro and in vivo study.
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Ebrahimi, Mohammad Hossein, Samadian, Hadi, Davani, Shiva Tavakol, Kolarijani, Nariman Rezaei, Mogharabian, Nasser, Salami, Mohammad Saeid, and Salehi, Majid
- Subjects
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BERBERINE , *NERVOUS system regeneration , *PERIPHERAL nervous system , *NANOPARTICLES , *IN vivo studies , *IN vitro studies , *ALGINATES , *NARINGIN - Abstract
In the current study, we prepared chitosan (Cs)/Alginate (Alg) hydrogel containing Berberine (Ber)-loaded Cs nanoparticles (NPs) and Naringin (Nar)-loaded Cs NPs as the promising biomaterials for peripheral nerve regeneration. The Ber- and Ner-loaded NPs were synthesized via the ion gelation method and incorporated into Cs/Alg hydrogel. The characterizations of NPs showed that Ber-loaded NPs have an average size of 594 nm with the encapsulation efficacy (EE) of 51.6 ± 7.4%, and Nar-loaded NPs have an average size of 636 nm with EE of 47.1 ± 5.8%. The pore size of Cs/Alg hydrogel and Cs/Alg/Ber/Nar hydrogel were 22 ± 11 and 32 ± 13 μm, respectively. It was observed that the swelling and weight loss value of the prepared hydrogels were suitable for nerve regeneration. The compression strength of Cs/Alg hydrogel and Cs/Alg/Ber/Nar hydrogel were 39.7 ± 4.7 kPa and 32.08 ± 6.8 kPa. The releasing measurement showed a burst release at the first days following a sustained release of up to about 90% for 24 days. The in vitro studies illustrated that the hydrogels were hemo- and biocompatible with the significant proliferative effect on PC12 cells. The animal studies showed that the treatment using the hydrogels significantly promoted nerve regeneration. Treatment of the damaged nerve using Cs/Alg/Ber/Nar hydrogel resulted in the sensory function recovery (hot plate latency of 4.66 ± 0.57 s), the motor function recovery (sciatic index function of −14.6 ± 3.7) and anatomical healing (the gastrocnemius muscle cross-sectional area of 2509 ± 142 μm2). In conclusion, the results indicate that the prepared hydrogels possess promising characteristics and significantly enhanced sensory and motor functional recovery, as well as anatomical healing. • Chitosan/Alginate hydrogel composited with Berberine and Naringin nanoparticles • The prepared hydrogels exhibited proper physicochemical properties. • The prepared hydrogels were hemo- and biocompatible. • The prepared hydrogel composite significantly promoted nerve regeneration. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
45. Native chicken-derived Lactobacillus spp. strains with high probiotic, cholesterol-assimilation and aflatoxin-degradation capabilities.
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Ebrahimi, Niloufar Amir, Jouzani, Gholamreza Salehi, and Ebrahimi, Mohammad Ali
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PROBIOTICS , *LACTOBACILLUS reuteri , *STREPTOCOCCUS mutans , *LACTOBACILLUS , *ANIMAL health , *SALMONELLA enterica , *LACTOBACILLUS casei - Abstract
Background and Objectives: Probiotics are added into the food or feed systems and provide beneficial effects to the human or animal health. This study aimed to isolate the gastrointestinal native Lactobacillus strains with high probiotic, cholesterol-assimilation and aflatoxin-degradation capabilities from native chickens. Materials and Methods: About 70 Lactobacillus isolates were isolated from ileum of the Fars province native chickens and were investigated for their probiotic properties. Results: Of 70 Lactobacillus isolates, 10 showed high probiotic capabilities, including survival at acidic conditions (pH up to 2.5), tolerance of 0.5% bile and 6-10% NaCl salts, growth in a wide range of temperature from 15 to 45°C, antagonistic effects against different important bacterial pathogens (Pseudomonas aeruginosa, Escherichia coli, Streptococcus mutans, Clostridium defficile, Enterococcus hirae, Salmonella enterica and Staphylococcus aureus) and sensitivity to some important antibiotics. The selected strains had an aggregation time less than 120 min. The 16S-rDNA sequencing showed that the selected strains were highly related to Lactobacillus reuteri and L. casei. Finally, the selected strains in this study along with 10 other probiotic strains isolated and characterized in our pervious study were used to evaluate their cholesterol assimilation and aflatoxin B1 degradation capabilities. The potentials of cholesterol assimilation of the selected strains were significantly different (P<0.05) and ranged from 2.3% to 99%. The highest content of cholesterol assimilation was obtained in isolates M20 and M4 with more than 98% absorption. Moreover, four strains 43, OR7, M21 and OR9 were able to absorb AFB1 with 58.6%, 52.33%, 47% and 31.6% efficiency respectively. Conclusion: It could be concluded that the strains 43, M21 and OR7 showed high probiotic potentials for application in the poultry industry. [ABSTRACT FROM AUTHOR]
- Published
- 2022
46. Anatomical Variations of the Mandibular Symphysis in a Normal Occlusion Population Using Cone-Beam Computed Tomography.
- Author
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SALEMI, Fatemeh, FARHADIAN, Maryam, and EBRAHIMI, Mohammad
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LIPS , *CONE beam computed tomography , *ANATOMICAL variation , *MANDIBLE , *COMPACT bone , *CUSPIDS , *TOMOGRAPHY - Abstract
This study aimed to assess the anatomical variations of the mandibular symphysis in a normal occlusion population using cone-beam computed tomography (CBCT). This retrospective cross-sectional study evaluated 200 CBCT scans of patients aged =17 with class I occlusion, 1-3 mm overbite and overjet, and <3 mm crowding. The CBCT scans were obtained with NewTom 3G scanner with the exposure settings of 110 kVp, 1.2 mA, 5.4 s time, and six-inch field of view and saved in NNT Viewer. The anterior loop length, labial bone thickness, mandibular bone height at the symphysis, and cortical bone thickness at the right and left canine teeth and central and lateral incisors were measured and compared between males and females and different age groups using one-way ANOVA. The intra- and inter-observer agreements for all landmarks were ICC >0.9 (excellent). The mean length of the anterior loop in females was significantly greater than that in males (P=0.02). Different age groups had significant differences in cortical bone width at the site of the left canine (P=0.03) and vertical bone height at the site of the right central incisor (P=0.05). The majority of parameters related to the mandibular symphysis were greater in normal occlusion males than females. Preoperative CBCT assessment of the mandibular symphysis can greatly help in diagnosis and treatment planning as well as bone harvesting from this area. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
47. Stator Short-Circuit Fault Detection and Location Methods for Brushless DFIMs Using Nested-Loop Rotor Slot Harmonics.
- Author
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Afshar, Mojtaba, Tabesh, Ahmadreza, Ebrahimi, Mohammad, and Khajehoddin, Sayed Ali
- Subjects
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INDUCTION machinery , *FAULT location (Engineering) , *STATORS , *ROTORS , *SHORT circuits , *FINITE element method , *SYNCHRONOUS generators , *PERMANENT magnet generators - Abstract
This article proposes and demonstrates a fault-detection method to locate interturn short circuits (ITSCs) in the stator windings of a brushless doubly fed induction machine (BDFIM). The detection of ITSC is important in machine health prognostics as ITSC is an early stage fault that may lead to other faults such as coil-to-coil and coil-to-ground. BDFIM consists of power and control windings in the stator that are magnetically coupled through a nested-loop rotor winding. Existing ITSC detection algorithms use rotor slot harmonics in stator current spectra as fault indicators for only conventional doubly fed induction machines. However, these algorithms cannot be applied to BDFIM due to its different stator/rotor winding structure. This article primarily proposes a new analytical formulation for the nested-loop rotor slot harmonics (NRSHs) as ITSC fault indicators in BDFIMs. Using NRSHs, a detection algorithm is also proposed to detect and locate ITSC in power/control windings of BDFIMs. The proposed algorithm is verified based on numerical analysis of a BDFIM using the finite-element method. The accuracy of the proposed fault-detection algorithm is also experimentally investigated and demonstrated using a BDFIM test rig. Both numerical and experimental test results confirm effectiveness of the proposed ITSC fault-detection algorithm. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
48. Socioeconomic inequality in tobacco expenditure in Iran: a cross-sectional analysis at national and subnational levels.
- Author
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Rezaei, Satar, Pulok, Mohammad Habibullah, and Ebrahimi, Mohammad
- Subjects
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HOUSEHOLD budgets , *HUMAN Development Index , *TOBACCO smoke , *TOBACCO products , *METROPOLITAN areas , *EQUALITY , *SMOKING cessation , *SOCIOECONOMIC status - Abstract
Background: Tobacco expenditure has adverse impacts on expenditure on basic needs and resource allocation of the households. Using data from a nationally representative survey, we measured socioeconomic inequality in tobacco expenditure as the share of household budget (TEHB) and explained its main determinants among Iranian households at the national and sub-national levels. Methods: This cross-sectional study used data from the Iranian Household Income and Expenditure Survey (IHIES), 2018. We included a total of 7649 households with tobacco expenditure more than zero in the analysis. Province-level data on the Human Development Index (HDI) was obtained from the Institute for Management Research at Radbound University. The concentration curve (CC) and the concentration index (C) were used to measure socioeconomic inequality in TEHB at national and sub-national levels. The C was decomposed to identify the factors explaining the observed socioeconomic inequality in TEHB. Results: At the national level, households with at least one smoker spent more than 5% of their budget for tobacco consumption in the last month. Households from the urban areas allocated less of their budgets on tobacco products compared to rural households (4.6% vs. 5.8%). Overall, TEHB was more concentrated among the poorer households (C = 0.1423, 95% CI: − 0.1552 to − 0.1301). In other words, the distribution of TEHB was pro-poor in Iran. Pro-poor inequality in TEHB was also found in urban (C = − 0.1707, 95% CI: − 0.1998 to − 0.1516) and rural (C = − 0.1314, 95% CI: − 0.1474 to − 0.1152) areas. We also found that pro-poor inequalities were higher in Iranian provinces with low HDI. The decomposition results indicate that wealth and education were the main factors contributing to the concentration of TEHB among the poorer households. Conclusion: This study found that TEHB was disproportionality concentrated among poorer households in Iran. The extent of inequality in TEHB was higher in urban areas and less developed provinces. Designing and implementing tobacco control interventions to decrease the smoking prevalence and increase smoking cessation could protect worse-off households against the financial burden of tobacco spending. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
49. Socioeconomic inequality in tobacco expenditure in Iran: a cross-sectional analysis at national and subnational levels.
- Author
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Rezaei, Satar, Pulok, Mohammad Habibullah, and Ebrahimi, Mohammad
- Abstract
Background: Tobacco expenditure has adverse impacts on expenditure on basic needs and resource allocation of the households. Using data from a nationally representative survey, we measured socioeconomic inequality in tobacco expenditure as the share of household budget (TEHB) and explained its main determinants among Iranian households at the national and sub-national levels.Methods: This cross-sectional study used data from the Iranian Household Income and Expenditure Survey (IHIES), 2018. We included a total of 7649 households with tobacco expenditure more than zero in the analysis. Province-level data on the Human Development Index (HDI) was obtained from the Institute for Management Research at Radbound University. The concentration curve (CC) and the concentration index (C) were used to measure socioeconomic inequality in TEHB at national and sub-national levels. The C was decomposed to identify the factors explaining the observed socioeconomic inequality in TEHB.Results: At the national level, households with at least one smoker spent more than 5% of their budget for tobacco consumption in the last month. Households from the urban areas allocated less of their budgets on tobacco products compared to rural households (4.6% vs. 5.8%). Overall, TEHB was more concentrated among the poorer households (C = 0.1423, 95% CI: - 0.1552 to - 0.1301). In other words, the distribution of TEHB was pro-poor in Iran. Pro-poor inequality in TEHB was also found in urban (C = - 0.1707, 95% CI: - 0.1998 to - 0.1516) and rural (C = - 0.1314, 95% CI: - 0.1474 to - 0.1152) areas. We also found that pro-poor inequalities were higher in Iranian provinces with low HDI. The decomposition results indicate that wealth and education were the main factors contributing to the concentration of TEHB among the poorer households.Conclusion: This study found that TEHB was disproportionality concentrated among poorer households in Iran. The extent of inequality in TEHB was higher in urban areas and less developed provinces. Designing and implementing tobacco control interventions to decrease the smoking prevalence and increase smoking cessation could protect worse-off households against the financial burden of tobacco spending. [ABSTRACT FROM AUTHOR]- Published
- 2020
- Full Text
- View/download PDF
50. Grid-Supporting Inverters With Improved Dynamics.
- Author
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Khajehoddin, Sayed Ali, Karimi-Ghartemani, Masoud, and Ebrahimi, Mohammad
- Subjects
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ELECTRIC inverters , *ENERGY storage , *STORAGE batteries , *PHOTOVOLTAIC power systems , *ELECTRIC power distribution grids , *DISTRIBUTED power generation , *RENEWABLE energy sources - Abstract
A new inverter control approach, called enhanced virtual synchronous machine (eVSM), is proposed based on the VSM concept. Unlike existing VSM approaches, the eVSM does not emulate the rotating inertia based on an assumption of the unlimited energy storage, but it deploys the physically existing inertia of the dc-link element. The eVSM adopts an innovative way of enlarging the inertia utilization range, which obviates the need for having a large dc-link element or a dedicated battery storage system, while still providing the same inertia response of an equivalent synchronous machine. Theoretical developments and numerical results presented in this paper confirm that the proposed eVSM can present a stabilizing support to the grid similar to a synchronous machine despite the small size of its dc-link element. Moreover, its transient responses can be improved beyond those of conventional synchronous machines thanks to the possibility of more flexibly adjusting damping and governor functions. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
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