819 research outputs found
Developing a fuzzy expert system to predict the risk of neonatal death
No full textIntroduction: This study aims at developing a fuzzy expert system to predict the possibility of neonatal death. Materials and Methods: A questionnaire was given to Iranian neonatologists and the more important factors were identified based on their answers. Then, a computing model was designed considering the fuzziness of variables having the highest neonatal mortality risk. The inference engine used was Mamdani's method and the output was the risk of neonatal death given as a percentage. To validate the designed system, neonates' medical records real data at a Tehran hospital were used. MATLAB software was applied to build the model, and user interface was developed by C# programming in Visual Studio platform as bilingual (English and Farsi user interface). Results: According to the results, the accuracy, sensitivity, and specificity of the model were 90, 83 and 97, respectively. Conclusion: The designed fuzzy expert system for neonatal death prediction showed good accuracy as well as proper specificity, and could be utilized in general hospitals as a clinical decision support tool. ©2016 Reza Safdari, Maliheh Kadivar, Mostafa Langarizadeh, Ahmadreaza Farzaneh Nejad, Farzaneh Kermani
Comparison Between Hesperidin, Coumarin, and Deferoxamine Iron Chelation and Antioxidant Activity Against Excessive Iron in the Iron Overloaded Mice
No full textObjective: Iron accumulation in the brain leads to the development of Alzheimer�s and Parkinson�s diseases. Nowadays, iron chelation therapy is the best way to decrease the side effects of iron and amyloid plaques accumulation. Iron chelators are commonly used for the treatment of Alzheimer�s disease. Previous studies have shown that natural products such as phenol and flavonoid compounds could chelate heavy metals. In the current study, we examined the iron chelation activity of hesperidin and coumarin on the brain tissue of iron-overloaded mice. Methods: 48 NMRI male mice were divided into eight groups (n = 6). Six groups were treated with iron dextran (100 mg/kg/day) four times a week for 6 weeks. After stopping the injections for a month, five groups of iron-overloaded mice were treated with hesperidin, coumarin, and desferal four times a week subsequent for four subsequent weeks. Finally, the mice were anesthetized, and blood samples were collected from the ventricle of the heart for subsequent examination. The brain tissues were isolated and fixed in the 4 paraformaldehyde solution for Perl�s staining. Results: The results show that hesperidin and coumarin could strongly chelate excessive iron from the serum and deposit iron from the brain tissue compared to desferal group. Catalase and super oxidase activity were decreased in the iron-overloaded group, but in the treated group by hesperidin and coumarin, the enzyme�s activity was increased significantly. Conclusion: Hesperidin and coumarin, as natural products, are powerful options to chelate iron ions and increase the activity of antioxidant enzymes. Copyright © 2022 Aalikhani, Safdari, Jahanshahi, Alikhani and Khalili
Design a fuzzy rule-based expert system to aid earlier diagnosis of gastric cancer
No full textIntroduction: Screening and health check-up programs are most important sanitary priorities, that should be undertaken to control dangerous diseases such as gastric cancer that affected by different factors. More than 50 of gastric cancer diagnoses are made during the advanced stage. Currently, there is no systematic approach for early diagnosis of gastric cancer. Objective: to develop a fuzzy expert system that canidentify gastric cancer risk levels in individuals. Methods: This system was implemented in MATLAB software, Mamdani inference technique applied to simulate reasoning of experts in the field, a total of 67 fuzzy rules extracted as a rule-base based on medical expert's opinion. Results: 50 case scenarios were usedto evaluate the system, the information of case reports is given to the system to find risk level of each case report then obtained results were compared with expert's diagnosis. Results revealed that sensitivity was 92.1 and the specificity was 83.1. Conclusions: The results show that is possible to develop a system that can identify High risk individuals for gastric cancer. The system can lead to earlier diagnosis, this may facilitate early treatment and reduce gastric cancer mortality rate. © 2018 Reza Safdari, Hadi Kazemi Arpanahi, Mostafa Langarizadeh, Marjan Ghazisaiedi, Hossein Dargahi, Kazem Zendehdel
A modified continuum surface force (M-CSF) model for two-phase flow problems in smoothed particle hydrodynamics
No full textThis work proposes a modified interfacial tension model based on the continuum surface force (M-CSF) in the context of smoothed particle hydrodynamics. This correction aims to enhance computational stability, improve force evaluation precision, and increase symmetry around the interface. Several two-phase flow benchmarks are solved using both the conventional and proposed CSF models, and the results are compared with each other and with the available literature. The results indicate that the modified model can efficiently increase the force evaluation accuracy in the pressure field at the interface. For instance, the relative error in pressure calculation using the proposed and conventional CSF models is 0.05% and 3.5%, respectively, when compared to the analytical solution, with both models having the same particle resolutions for the droplet deformation problem. In predicting the critical surface tension for hydrodynamic instabilities, such as the Rayleigh-Taylor instability, the M-CSF methodology exhibits much better alignment with existing theories, showing less than 5% deviation, while conventionally used CSF models can deviate up to 15% for the same problem. These findings confirm the superiority of the proposed methodology in evaluating interfacial forces, even in complex hydrodynamic instabilities.</p
Evaluación de eficiencia y transferencia de masa en un extractor pulsado con relleno
No full textO presente trabalho tem por objetivo investigar os parâmetros operacionais no desempenho de uma coluna de extração pulsada com recheio de anéis de Raschig. Para alcançar o objetivo proposto, foi utilizado o sistema água + ácido acético + 1-butanol a 25°C e 1 atm. Após os experimentos o desempenho da coluna foi avaliado a partir do cálculo da eficiência e do coeficiente global de transferência de massa. Os modelos de Murphree (1925) e Kawase (1990) foram utilizados para o cálculo da eficiência. Os modelos escolhidos apresentaram valores coerentes. Já para o cálculo do coeficiente global de transferência de massa utilizou-se seis modelos distintos: Plug Flow Model (PFM), Safari et al. (2012), Kister (1992), Torab-Mostaedi e Safdari (2009b), Modelo de difusão e GhaffariTooran et al. (2009). Sendo que os modelos de Torab-Mostaedi e Safdari (2009b) e GhaffariTooran et al. (2009) não apresentaram valores coerentes. Com a análise dos resultados, notou-se que tanto para eficiência quanto para o coeficiente global de transferência de massa houve uma influência positiva dos parâmetros operacionais analisados. Sendo a razão das vazões quem mais influenciou na eficiência da coluna, apresentando um aumento percentual de 33,57%. Por fim, um modelo empírico foi desenvolvido com o intuito de correlacionar a eficiência da coluna com os parâmetros operacionais. A equação mostrou boa concordância com a equação de Murphree, apresentando um desvio médio de 7,35%. Assim foi possível constatar a eficácia da inserção do recheio e da pulsação na extratora como uma forma de potencializar a transferência de massa.Liquid-liquid extraction, or solvent extraction, is a unitary operation designed to separate one or more components from the insertion of a liquid phase that has more affinity with the components of interest. It is a technique used in various industrial process including the food industry, petrochemical and biochemical. Thus, the present work aims to investigate the operational parameters in the performance of a pulsed packed extraction column. The packed used in the extractor ir Raschig’s rings. For this, 30 runs were performed with aqueous acetic acid solution (solute) and 1-butanol solution (solvent) in order to obtain concentration data in the extract and raffinate and with these data to calculate column efficiency and mass transfer coefficient. The Murphree (1925) and Kawase (1990) models were used to calculate the efficiency. The two models chosen for the efficiency calculation presented consistent values. For the calculation of the mass transfer coefficient, six different models were used: Plug Flow Model (PFM), Safari et al. (2012), Kister (1992), Torab-Mostaedi and Safdari (2009b), Diffusion Model and GhaffariTooran et al. (2009). Among these models, two did not present coherent values: Torab-Mostaedi and Safdari (2009b) and GhaffariTooran et al. (2009). With the analysis of the results it was noted that for both efficiency and mass transfer coefficient there was a positive influence. The flow ratio was the one that most influenced column efficiency, with a percentage increase of 33.57%. Finally, an empirical model was developed to correlate column efficiency with operational parameters. The equation showed good agreement with the Murphree equation, presenting an average deviation of 7.35% which is a relatively low deviation. Thus it was possible to verify the usefulness of the packed insertions and pulsation in the extractor as a way to improve the mass transfer.El presente trabajo tiene como objetivo investigar los parámetros operativos en el rendimiento de una columna de extracción pulsada de relleno, el relleno utilizado fue anillos de Raschig. Para lograr los objetivos propuestos, se usó el sistema de agua + ácido acético + 1-butanol a 25°C y 1 atm. Después de los experimentos, se evaluó el rendimiento de la columna a partir del cálculo de eficiencia y el coeficiente de transferencia de masa. Se utilizaron los modelos Murphree (1925) y Kawase (1990) para calcular la eficiencia. Los modelos elegidos presentaron valores coherentes. Para el cálculo del coeficiente de transferencia de masa, se utilizaron seis modelos diferentes: Plug Flow Model (PFM), Safari et al. (2012), Kister (1992), Torab-Mostaedi e Safdari (2009b), Modelo de difusión y Ghaffari Toooran et al. (2009). Torab-Mostaedi y Safdari (2009b) y GhaffariTooran et al. (2009) no presentaron valores coherentes. Con el análisis de los resultados, se observó que tanto para la eficiencia como para el coeficiente de transferencia de masa había una influencia positiva de los parámetros operativos analizados. La relación de flujo fue la que más influyó en la eficiencia de la columna, con un aumento porcentual del 33,57%. Finalmente, se desarrolló un modelo empírico para correlacionar la eficiencia de la columna con los parámetros operativos. La ecuación mostró un buen acuerdo con la ecuación de Murphree, presentando una desviación promedio de 7,35%. Por lo tanto, fue posible verificar la eficiencia de la inserción de relleno y la pulsación en la columna de extracción como una forma de mejorar la transferencia de masa
FITC-conjugated single chain Nimotuzumab can specifically recognize and enter EGFR-overexpressing cells
No full textThe epidermal growth factor receptor (EGFR) is regarded as an ideal target for cancer therapy and imaging. EGFR-targeting antibodies or antibody fragments can be engaged to specifically deliver small molecules with therapeutic or diagnostic properties to EGFR-overexpressing cancer cells. Cell-penetrating peptides (CPPs) are short amino acid sequences that are added to drug carriers or recombinant proteins and are believed to increase cellular internalization. In the current study, we evaluated the ability of FITC-conjugated single-chain Nimotuzumab molecules (containing or lacking CPP) in recognizing and entering EGFR-overexpressing cancer cells. The molecules were found to enter the cancer cells in an efficient manner and emit signals. No obvious difference was found between CPP-containing and CPP-lacking molecules in entering cancer cells. © 2022, The Author(s), under exclusive licence to Springer Nature B.V
The translation inhibitors kasugamycin, edeine and GE81112 target distinct steps during 30S initiation complex formation
No full textDuring bacterial translation initiation, the 30S ribosomal subunit, initiation factors, and initiator tRNA define the reading frame of the mRNA. This process is inhibited by kasugamycin, edeine and GE81112, however, their mechanisms of action have not been fully elucidated. Here we present cryo-electron microscopy structures of 30S initiation intermediate complexes formed in the presence of kasugamycin, edeine and GE81112 at resolutions of 2.0-2.9 & Aring;. The structures reveal that all three antibiotics bind within the E-site of the 30S and preclude 30S initiation complex formation. While kasugamycin and edeine affect early steps of 30S pre-initiation complex formation, GE81112 stalls pre-initiation complex formation at a further step by allowing start codon recognition, but impeding IF3 departure. Collectively, our work highlights how chemically distinct compounds binding at a conserved site on the 30S can interfere with translation initiation in a unique manner
A NURBS-based interface-enriched generalized finite element scheme for the computational analysis and design of high temperature microvascular composites
No full textComputational studies on multifunctional microvascular composite materials for high temperature application have focused on simple microchannel geometries [1–2]. Motivated by recent advances in the manufacturing of microvascular composites based on a sacrificial fiber technique that allows a complex network of curved microchannels to be embedded in the material [3], we develop an Interface Enriched Generalized Finite Element Method (IGFEM) [4] with Non-Uniform Rational B-Splines (NURBS) to analyze the impact of the microchannel network on the thermal field in the composite component [5]. By capturing the gradient discontinuity present at the microchannels, the method is able to simulate efficiently and accurately the thermal response of the microvascular composite without the need for a mesh that conforms to the geometry of the microchannels. We show that near-optimal convergence rate can be achieved and that IGFEM is more accurate than standard finite element method for coarse meshes when the enrichment functions are constructed using the NURBS description of the curved microchannels. Verification studies conducted against a detailed multiphysics model based on the Navier–Stokes equation for the fluid shows that the much simpler line source/sink model is very accurate for problems involving microvascular plates and fins. Various application problems are presented to demonstrate the efficiency, flexibility and accuracy of the proposed method. REFERENCES [1] Soghrati, S., Thakre, P.R., White, S.R., Sottos, N.R., Geubelle, P.H. Computational modeling and design of actively-cooled microvascular materials. Int. J. Heat Mass Transfer. 2012, 55, 5309–5321 [2] Soghrati, S., Najafi, A.R., Hughes, K.M., Lin, J.H., White, S.R., Sottos, N.R., Geubelle, P.H. Computational analysis of actively-cooled 3D woven microvascular composites using a stabilized interface-enriched generalized finite element method. Int. J. Heat Mass Transfer. 2013, 65, 153–164. [3] Esser-Kahn, A.P., Thakre, P.R., Dong, H., Patrick, J.F., Vlasko-Vlasov, V.K., Sottos, N.R., Moore, J.S., White, S.R. Three-dimensional microvascular fiber-reinforced composites. Advanced Materials. 2011, 23, 3654–3658. [4] Soghrati, S., Aragón, A.M., Duarte, C.A., Geubelle, P.H. An interface-enriched generalized FEM for problems with discontinuous gradient fields. Int. J. Numer. Methods Eng. 2012, 89, 991–1008. [5] Tan, M.H.Y., Safdari, M., Najafi, A.R., Geubelle, P.H. A NURBS-based interface-enriched generalized finite element scheme for the thermal analysis and design of microvascular composites. 2014 (submitted)
Adopted mobile learning business model for Iran
No full textPresent research offers mobile learning business model in Iran context. In this regard, reference business models are studied and among them Business Model Ontology (Osterwalder, 2004)is selected as the reference model for this study which is applied for m-learning business for Iran during 3 months. The selected business model has been customized. Then in a subsequent stage, the exploratory qualitative study using case study method has been adopted. Iranian existing companies in this field have been selected as our prototype sample based on their connection or potentiality to the subject of the study. To make sense out of the data, it was organized according to a classificatory scheme developed on the basis of the interviews. Items were identified from the data and defined according to their general properties and dimensions. We could recognize main elements of business model and applied them to mobile learning in Iran. Furthermore,we could explain the internal relationships among modules of the adopted business model. According to mobile learning infrastructure as well as a fragile and new essence of mobile learning in Iran as a developing country, sub-elements of current business model modules are varied in comparison with other countries especially developed countries. Therefore we think it requires many relevant activities to support adopted sub-elements particularly in marketing that should be attained target customers, maintained and supported them. It is necessary firstly customers should accept mobile learning industry as a new phenomenon in Iran then they can trust it and became loyal customer.Validerat; 20101217 (root
Simulation of the microlevel damage evolution in polymer matrix composites
No full textA 3D Isogeometric Interface-Enriched Generalized Finite Element Method (IIGFEM) is developed to analyze problems with complex, discontinuous gradient fields commonly observed in the structural analysis of heterogeneous materials including polymer matrix composites [1]. In the proposed approach, the mesh generation process is significantly simplified by utilizing simple structured meshes that do not conform to the complex microstructure of the heterogeneous media. Non-Uniform Rational B-Splines, commonly used in computer-aided design, are adopted in the IIGFEM to augment the finite element approximation space and capture the weak discontinuity present along material interfaces. The IIGFEM offers many advantages, such as the simplicity and accuracy of numerical integration, the straightforward implementation of essential boundary conditions, and the flexibility in the choice of the local solution refinement The ability to model complex material interfaces and the mesh independence are two of key features of the IIGFEM that enable it to tackle problems with evolving material response, such as computational study of damage in solids. Here, we utilize the IIGFEM scheme to study the impact of microstructural details on the initiation and evolution of the damage in polymer matrix composites. For this purpose, in this study, we incorporate a three-parameter isotropic damage model [2] into our IIGFEM solver to capture the fracture response of the matrix in a unidirectional composite layer. To bypass numerical issues associated with mesh bias, we use a viscous regularization scheme proposed by Simo and Ju [3]. The numerical stability of the proposed approach is studied and its advantages and limitations are discussed in detail. Finally, a number of numerical examples are presented to demonstrate the effect of RVE size and filler volume fraction on the damage behavior of fiber-reinforced polymer matrix composites. REFERENCES [1] Safdari, M., Najafi, A.R., Sottos, N.R., Geubelle, P.H. An Isogeometric Interface-Enriched Generalized Finite Element Method (IGFEM) for problems with complex discontinuous gradient field. Submitted (2014). [2] Matous, K., Kulkarni, M.G., Geubelle, P.H. Multiscale cohesive failure modeling of heterogeneous adhesives. Journal of the Mechanics and Physics of Solids. 2008, 56, 1511–1533. [3] Simo, J.C., Ju, J.W. Strain- and stress-based continuum damage models—ii. computational aspects. International Journal of Solids and Structures. 1987, 23(7), 841–869
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